สิทธิบัตรเรื่ องเต็มจากฐาน EPO Worldwide (http://gb.espacenet.com) ปี 2001-2005
เกี่ยวกับ “Vulcanized
Rubber”
1. AU2003205769 - 04.09.2003
METHOD FOR MANUFACTURING A SOLE FOR SHOES, COMPOSED OF A TREAD SOLE MADE OF
VULCANIZED RUBBER COUPLED TO A POLYURETHANE MID-SOLE
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=AU2003205769
Inventor(s):
LORENZIN LORENZO [IT] (--)
Applicant(s):
MAIN GROUP SPA [IT] (--); LORENZIN LORENZO [IT] (--)
IP Class 4 Digits: B29D; A43B
IP Class:
B29D31/51; A43B13/04; B29D31/518
E Class: A43B13/04; B29D31/51C2; B29D31/518B
Application Number:
WO2003EP01510 (20030214)
Priority Number: IT2002PD00051 (20020227)
Family: AU2003205769
Equivalent:
EP1478252; ITPD20020051
Cited Document(s):
WO02052971; GB2184638; EP0311120; US4245406; DE3616874
Abstract:
A METHOD FOR MANUFACTURING A SOLE FOR SHOES COMPOSED OF A TREAD SOLE MADE
OF VULCANIZED RUBBER THAT IS COUPLED TO A POLYURETHANE MID-SOLE, THE METHOD
COMPRISING THE STEPS, PERFORMED CONTINUOUSLY IN A MOLD, OF MOLDING THE RUBBER
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TREAD APPLYING DIRECTLY TO THE RUBBER TREAD, DURING VULCANIZATION, AN ADHESIVE
CONSTITUTED BY AN AQUEOUS DISPERSION OF THERMOPLASTIC POLYURETHANE COMBINED
WITH AN ACTIVATOR THAT CAUSES THE CROSSLINKING OF THE POLYURETHANE CAUSING
THE EVAPORATION OF THE WATER DISPERSED IN THE ADHESIVE AND DEPOSITING THE
POLYURETHANE THAT CONSTITUTES THE MID-SOLE ON THE VULCANIZED RUBBER
TREAD.Description:
METHOD FOR MANUFACTURING A SOLE FOR SHOES, COMPOSED OF A TREAD SOLE MADE OF
VULCANIZED RUBBER COUPLED TO A POLYURETHANE MID-SOLE Technical Field
The present invention relates to the manufacture of a sole for shoes that is composed of a tread sole
made of vulcanized rubber coupled to a polyurethane mid-sole.
Background Art
The problems encountered in joining vulcanized rubber and polyurethane are known; these two
materials, at least the ones used up to now, are in fact substantially mutually incompatible and
particular techniques are necessary in order to associate them.
Rubber mixtures, developed specifically for coupling to polyurethane (free from oily substances
which, once the rubber has been vulcanized, migrate to the surface) are first vulcanized for times
and at temperatures required for currently commercially available mixtures (approximately 170 C).
The soles are then washed with solvents in order to remove the residues of release agent, dust and
contamination caused by handling by the operators (fatty substances of the skin).
The next step is drying, in order to eliminate the traces of solvent that can compromise the action of
the primer applied in the subsequent step.
Then a chlorine-based primer is applied (halogenation) by spraying onto the inner surface of the
tread, which will then make contact with the polyurethane.
The presence of the primer based on chlorinated substances is currently indispensable for the
subsequent steps and therefore to achieve coupling between the rubber tread and the polyurethane
mid-sole.
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The subsequent step consists in resting for 24 hours at a constant temperature in order to ensure
that the primer is completely absorbed by the
rubber (the action of the primer consists in modifying chemically the surface of the
rubber,"activating"it).
Once the above resting step has ended, a polyurethane-based adhesive is sprayed and the
adhesive is then left to dry for a period between a few hours and a day at ambient temperature
(depending on the vapor pressure of the solvent of the adhesive).
It is necessary to be certain that the adhesive is dry before the polyurethane can be poured onto it.
The tread sole is then ready to be positioned in the mold.
Inside the mold, the adhesive is activated by irradiation with an IR lamp (heat shock) and
polyurethane is finally injected or poured.
This manufacturing technique clearly has a number of problems: the need to prepare the tread soles
separately from the polyurethane molding apparatus and to store them due to production logistics
reasons; the need to let the tread soles cool at least until they reach a temperature that is compatible
with the polyurethane molding pressure; the need, due to storage, for washing with a solvent that is
expensive and employs toxic products; the need to allow elapsing of a relatively long time that is not
compatible with continuous production after application of the primer; the need to let the adhesive
dry after spraying; the need to allow the adhesive time (considerable time) to self-activate.
As an alternative to treatment with a primer, other solutions have been adopted which entail for
example positioning between the vulcanized rubber and the polyurethane a felt that must be
compatible with both materials.
In view of the problems mentioned above, it is evident that the tread sole made of vulcanized rubber
cannot be prepared in the same production cycle as the sole or shoe, but must be prepared first and
separately, allowed to cool and then subjected to surface treatment.
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In the other cases, an accessory component must be used.
The production of shoes with a vulcanized rubber tread and a
polyurethane mid-sole is therefore scarcely convenient and excessively expensive.
On the other hand, the advantages of a sole with a vulcanized rubber tread and a remaining part
(mid-sole) made of polyurethane would be considerable, since a vulcanized rubber tread is highly
resistant to wear and thermal abrasion and a polyurethane mid-sole is very light and comfortable.
Disclosure of the invention
The aim of the present invention is to provide, in a same operating cycle, a sole with a vulcanized
rubber tread that is coupled to a polyurethane mid- sole.
Within this aim, an object of the invention is to provide a method that does not require holding times
between the preparation of the vulcanized rubber sole and the subsequent coupling to a
polyurethane mid-sole formed within a mold.
A further object is to provide a method that does not require treatment of the vulcanized rubber sole
before injecting or pouring the polyurethane into the mold.
This aim and these and other objects that will become better apparent hereinafter are achieved by a
method for manufacturing a sole for shoes, composed of a tread sole made of vulcanized rubber that
is coupled to a polyurethane mid-sole, comprising the steps, performed continuously in a mold, of :
molding the rubber tread; - applying directly to said rubber tread, during vulcanization, an adhesive
constituted by an aqueous dispersion of thermoplastic polyurethane combined with an activator that
causes the crosslinking of the thermoplastic polyurethane; causing the evaporation of the water
dispersed in said adhesive; depositing the polyurethane that constitutes the mid-sole on said
vulcanized rubber tread.
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Advantageously, such activator that causes the crosslinking of the polyurethane is a compound
based on isocyanate treated so as to be less reactive with water.
Further characteristics and advantages of the invention will become better apparent from the
following detailed description of the steps of execution of the method, which is given hereafter by
way of non-limitative example.
Ways of carrying out the Invention
The method for manufacturing a sole for shoe composed of a vulcanized rubber tread sole coupled
to a polyurethane mid-sole comprises a first step, in which a rubber is vulcanized that has a mixture
as disclosed in WO 02/052971 in the name of the same Applicant and composed of : al) a
vulcanizable nitrile rubber (NBR); a2) at least one hydroxylated acrylic resin; a3) at least one
hydrocarbon resin; a4) at least one reinforcing filler; as) at least one vulcanization accelerator.
The nitrile rubber that is used is conveniently of the medium-high nitrile type with low Mooney value
(low viscosity).
A rubber of this type is a butadiene-acrylonitrile copolymer that is technically known by the acronym
NBR.
The mixture contains a hydroxylated acrylic resin, i. e. , a polyacrylic resin with an OH content of less
than 2.
Such resin is preferably employed in a solvent and its percentage by weight is between 4 and 6% of
the overall weight of the mixture.
The mixture further comprises a hydrocarbon resin of the family of aliphatic resins of petrochemical
origin.
Such hydrocarbon resin, preferably in the solid state, is present in a percentage by weight of 3 to
5% with respect to the overall weight of the mixture.
The hydrocarbon resin is a combination of C5 hydrocarbon chains.
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A siliceous reinforcing filler is also added to the mixture.
Such reinforcing filler is preferably precipitated amorphous silica, or is a mixture containing 85 to
90% SiO2 with a BET value of 150 to 200 m2/gr.
The reinforcing filler is present in a percentage by weight from 20 to 25% of the overall weight of the
mixture.
The vulcanization accelerator is of the class of mercaptans, with the addition of an ultra accelerator
of the thiuram class.
The accelerator is introduced in the mixture in a percentage by weight between 1 and 1.5% of the
overall weight of the mixture.
The mixture described above is deposited in the mold for example by means of an injection-pouring
unit (temperature: 60-70 C depending on environmental conditions) and then vulcanized preferably
at 130 C for 3 minutes.
Conveniently, the variations in thickness of the rubber tread sole must not be greater than 10%, in
order to avoid compromising the uniformity of the degree of vulcanization.
The subsequent step is the application of an adhesive according to the invention with a spray gun,
preferably depositing a quantity of 3-4 grams per sole.
It is necessary to ensure the constancy of the thickness of adhesive film along the entire surface to
be bonded by adhesive.
The adhesive is a bonding agent constituted by an aqueous dispersion of thermoplastic
polyurethane, combined with a compound based on isocyanate treated to be less reactive with water.
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The two components are mixed by the user before use, depending on the reactivity of the
isocyanate-based compound, which acts as an activator, causing the crosslinking of the
polyurethane component.
The dispersion is preferably 1 part of polyurethane adhesive and 0.5 parts of water.
Advantageously, the isocyanate-based compound is approximately 3-4%
by weight and comprises a quantity between 0.40 and 0.45% by weight of hexamethylene
diisocyanate and less than 95% by weight of aliphatic polyisocyanate.
Since the isocyanate-based compound reacts with water (and the adhesive is an aqueous
dispersion of polyurethane), as mentioned earlier it is convenient to treat it so as to reduce its
reactivity and therefore extend the time by which it must be used.
The ratios of dilution with water depend in any case on the layer of film of adhesive on the surface of
the rubber tread sole; if the adhesive is diluted excessively when it is sprayed, it atomizes
excessively and does not cling well to the surface of the tread sole, forming large drops.
If the product is instead excessively concentrated, uniform distribution on the surface does not
occur.
Conveniently, it is possible to use as an adhesive a polyurethane component known as 9620/DD, of
the company F. lli Zucchini of Ferrara, and as a treated isocyanate-based compound for example the
one commercially known as ATTIVATORE VKD, again of the company F. lli Zucchini of Ferrara, which
has a pot life of 8 hours (time for which the adhesive remains efficient) and requires complete
replenishment after 4 hours.
This adhesive is currently known in a technical field that is very different from the field of shoemaking machines, i. e. , for use in the joining of PVC claddings to MDF panels.
The water contained in the dispersion of adhesive evaporates due to the heat supplied by the freshly
vulcanized rubber (the head is supplied indirectly by the mold by means of the rubber tread) and by
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irradiation with an IR lamp (for example, with a 6000 W lamp the exposure time can be between 5
and 15 sec).
The step of forced drying of the adhesive is recommended in order to shorten the normal drying
times, which are between 30 and 40 minutes at
ambient temperature for the 9620/DD adhesive in the known use for joining PVC claddings to MDF
panels; such values are not suitable for the mass production of shoe soles.
The final step is the injection or pouring of the polyurethane that constitutes the mid-sole.
As clearly shown, the preparation of the rubber tread sole and the subsequent operation for
coupling with the polyurethane mid-sole occur in the same machine and with an operating cycle in
which the steps occur continuously one after the other, without idle times or pauses.
The step of storage and therefore of washing pretreatment, and the application of the chlorinebased primer (halogenation), which among other issues entails severe risks for the health of the
operator and problems of corrosion of mechanical components, are eliminated.
From what has been described and illustrated it is evident that the intended aim and all of the
objects have been achieved, and that in particular a tread sole made of vulcanized rubber coupled
to a polyurethane mid-sole has been provided and that all of the above occurs with a succession of
steps that can be performed in a single machine and sequentially.
Clearly, starting from the same inventive concept, equivalent components may be used.
The disclosures in Italian Patent Application No. PD2002A000051 from which this application claims
priority are incorporated herein by reference.Claims:
CLAIMS
1. A method for manufacturing a sole for shoes, composed of a tread sole made of vulcanized
rubber that is coupled to a polyurethane mid-sole, comprising the steps, performed continuously in a
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mold, of : --molding the rubber tread; - applying directly to said rubber tread, during vulcanization,
an adhesive constituted by an aqueous dispersion of thermoplastic polyurethane combined with an
activator that causes the crosslinking of the thermoplastic polyurethane ; causing the evaporation of
the water dispersed in said adhesive; depositing the polyurethane that constitutes said mid-sole on
said vulcanized rubber tread.
2. The method according to claim 1, wherein said aqueous dispersion of thermoplastic polyurethane
is 1 part of polyurethane and 0.5 parts of water.
3. The method according to claim 1, wherein said activator that causes the cross-linking of
polyurethane is a compound based on isocyanate treated to have less reactivity with water.
4. The method according to claim 3, wherein said isocyanate-based compound is approximately 34% by weight.
5. The method according to claim 4, wherein said isocyanate-based compound comprises an
amount substantially between 0.40 and 0.45% by weight of hexamethylene diisocyanate and less
than 95% by weight of aliphatic polyisocyanate.
6. The method according to claim 1, wherein said adhesive is applied in an amount of substantially
3-4 grams per sole.
7. The method according to claim 1, wherein the step of causing the evaporation of the water
dispersed in the adhesive comprises making said water evaporate by conduction and
irradiation/convection with an external device.
8. The method according to claim 7, wherein said irradiation is performed
with a lamp having a power of 6000 W for a time between 5 and 15 seconds.
9. The method according to claim 1, wherein said adhesive is applied with a spray gun.
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10. Use, as an adhesive in a method for manufacturing a sole for shoes composed of a tread sole
made of vulcanized rubber coupled to a polyurethane mid-sole, of a bonding agent composed of an
aqueous dispersion of thermoplastic polyurethane combined with an activator that causes the crosslinking of the polyurethane.
11. The use according to claim 10, wherein said aqueous dispersion of thermoplastic polyurethane
is 1 part of polyurethane and 0.5 parts of water.
12. The use according to claim 10, wherein said activator that causes the cross-linking of the
polyurethane is a compound based on isocyanate, treated so as to be less reactive with water.
13. The use according to claim 12, wherein said isocyanate-based compound is approximately 34% by weight.
14. The use according to claim 13, wherein said isocyanate-based compound comprises a quantity
substantially between 0.40 and 0.45% by weight of hexamethylene diisocyanate and less than 95%
by weight of aliphatic polyisocyanate.
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2. CA2462612 - 24.04.2003
ENVIRONMENTALLY FRIENDLY ADHESIVES FOR BONDING VULCANIZED RUBBER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=CA2462612
Inventor(s):
GREEN CHRISTIAN C (--); MOWREY DOUGLAS H (--)
Applicant(s):
LORD CORP [US] (--)
IP Class 4 Digits: C09J
IP Class:
C9J123/28; C9J115/02; C9J11/02
E Class: C08L15/02+B; C08L23/10+B5; C09J11/02; C09J123/28+B
Application Number:
WO2002US33362 (20021017)
Priority Number: US20010330033P (20011017); US20020222545 (20020816)
Family: CA2462612
Cited Document(s):
US4119587; US5268404; GB2155488; US3830784
Abstract:
ADHESIVE COMPOSITIONS EFFECTIVE FOR BONDING RUNNER TO METAL AND CONTAINING
NO MORE THAN ABOUT 1000 PPM OF LEAD ESPECIALLY ADAPTED TO BOND VULCANIZED
ELASTOMERS TO RIGID SUBSTRATES, LIKE METAL ARE DISCLOSED. THE ADHESIVES ARE
USEFUL IN COMBINATION WITH PRIMER COATS, AND AS ONE-COAT ADHESIVES AND PROVIDE
DURABLE, RUBBER TEARING PRIMARY ADHESIVE BONDS AFTER EXPOSURE TO HARSH
CONDITIONS. THE ADHESIVES EXHIBIT EXCELLENT BOND VERSATILITY, SWEEP RESISTANCE,
AND IN-CAN STORAGE STABILITY. IN ONE EMBODIMENT, THE ADHESIVE COMPOSITIONS OF
THE PRESENT INVENTION CONSIST ESSENTIALLY OF LESS THAN 1000 PPM OF LEAD, AT LEAST
ONE DILUENT AS WATER OR ORGANIC SOLVENT, A HALOGEN-CONTAINING FILM FORMER,
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OPTIONALLY A NITROSO COMPOUND, BROMINATED DICHLOROBUTADIENE, AND/OR
ADHESION PROMOTER, AND AN ACID SCAVENGER COMPRISING ZINC PHOSPHATE.Description:
ENVIRONMENTALLY FRIENDLY ADHESIVES FOR BONDING VULCANIZED
RUBBER
FIELD OF THE INVENTION [0001] The invention relates to formulated adhesives applied to bond
rubber to substrates like metal, during the vulcanization process which generally contain a
crosslinking agent and one or more halogenated polymers/film formers, characterized by low levels
of lead compounds.
BACKGROUND OF THE INVENTION [0002] Bonding of rubber vulcanizates to substrates,
especially metal is conventionally obtained by two-coat primer-overcoat adhesive systems or onecoat primerless systems. In order to provide acceptable bonding, adhesive compositions must
exhibit excellent bonding as retention of rubber on the substrate after bond destruction, adequate
sweep resistance i. e., ability of the uncured adhesive coating on the substrate to remain undisturbed
against the force of injected green rubber into the mold cavity, good storage stability of the wet
adhesive and durable adhesion under extreme environmental conditions, typically measured by the
hot tear test (ASTM D-429) boiling water and salt spray tests (ASTM B-117-97, for example).
[0003] The treatment of metals using zinc phosphate in conversion coating processes is well known,
for example as disclosed in 6,019, 858.
[0004] In the literature relating to adhesives for bonding rubber to metal (RTM), the following
additives such as organosilanes, dispersing agents, adhesion promoting resins such as phenol
formaldehyde, crosslinkers such as nitrosobenzenes, and maleimide compounds, carbon black,
silica, calcium carbonate, oxides of the metals Al, Ca, Zn, Mg, Pb, Zr, also zirconium salts, e. g.
zirconium aluminate, and lead salts of inorganic and/or organic acids, e. g. basic lead carbonate.
The use of lead compounds is widely practiced in RTM adhesives
because these materials impart essential heat and corrosion resistance of the bond between the
vulcanized elastomer and the metal.
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[0005] U. S. Pat. No. 3,640, 941 describes a one-coat rubber-to-metal adhesive containing four
essential ingredients: (a) a graft polymer of a polybutadiene and a substituted cyclopentadiene
monomer, (b) dibasic lead phosphite, (c) resorcinol and (d) a volatile solvent. In this adhesive system
between 25-150 parts by weight of dibasic lead phosphate per 100 parts of polymer is described as
necessary to achieve the desired performance.
[0006] U. S. Pat. No. 4,119, 587 discloses a one-coat adhesive composition comprised of the three
essential constituents: (a.) halogenated polyolefinic, (b) aromatic nitroso compound, and (c) lead
salts.
[0007] U. S. Pat. No 5,268, 404 discloses adhesives comprising a halogenated polyolefin, an
aromatic nitroso compound, metal oxide such as zinc oxide or magnesium oxide, and optionally a
vulcanizing agent such as sulfur or selenium, a. phenolic epoxy resin, or carbon black.
[0008] Lead compounds useful as additive in RTM adhesives provide either an acid scavenging
feature and/or corrosion resistance in conjunction with halogenated polymers.
Due to the increasing demand from both government and industry to use adhesive materials that do
not contain bio-accumulative ingredients. Conventional rubber-to-metal adhesives have required
effective amounts of lead compounds and selenium to provide essential resistance to heat and
corrosion. It would be desirable to provide adhesives for bonding of rubber to metal during the
vulcanization processes that contain less than 1000 ppm of undesirable ingredients such as lead
and selenium-containing compounds while at the same time providing comparable heat and
corrosion resistance.
[0009] The elimination of additives based on lead down to ppm levels presents a problem of finding
a suitable replacement that provides for versatile performance in respect to the variety of
vulcanizable elastomer types. In addition to the problem of versatility, especially in
respect to one-coat adhesive systems, is a general inability to afford optimum adhesion, particularly
at elevated temperatures, poor storage stability, poor resistance to pre-bake, poor corrosion
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resistance and poor resistance of the adhesive bond to environmental conditions such as solvents,
moisture and the like.
[0010] In view of the potential adverse environmental effects posed by the presence of lead, and in
light of the technical challenge for minimizing lead levels, it would be highly desirable if a. one-coat
rubber-to-metal bonding adhesive composition could be developed which possesses all the
aforementioned characteristics without the need of lead compounds.
SUMMARY OF THE INVENTION [0011] A general object of the invention is to provide adhesive
compositions containing no more than about 1000 ppm of lead that can bond vulcanized elastomers
to rigid substrates, especially metal that provide durable, rubber tearing primary adhesive bonds
after exposure to harsh conditions. The adhesives exhibit excellent bond versatility, sweep resistance,
and in-can storage stability.
[0012] In one embodiment, the adhesive compositions of the present invention consist essentially of
less than 1000 ppm of lead, at least one solvent, a halogenated polyolefin, a nitroso compound or
brominated dichlorobutadiene, zinc phosphate and optional maleimide compound.
[0013] In a specific aspect of the invention there is provided rubber-to-metal adhesive system
containing less than about 1000 ppm of lead and consisting essentially of chlorosulfonated
polyethylene and/or chlorinated natural rubber, a poly-C-nitroso compound or brominated
dichlorobutadiene polymer, carbon black, silica, zinc phosphate, and at least one component
selected from the group consisting of a. polyisocyanate, epoxy resin, and a maleimide compound.
[0014] In another specific aspect of the invention there is provided rubber-to-metal adhesive system
containing less than about 1000 ppm of lead and consisting essentially of chlorosulfonated
polyethylene and chlorinated natural rubber, a poly-C-nitroso compound, carbon black, silica, zinc
phosphate, and at least one component selected from the group consisting of a polyisocyanate,
epoxy resin and a maleimide compound.
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[0015] In another specific aspect of the invention there is provided rubber-to-metal adhesive system
containing less than about 1000 ppm of lead and consisting essentially of chlorosulfonated
polyethylene and chlorinated natural rubber, brominated dichlorobutadiene polymer, carbon black,
silica, zinc phosphate and at least one component selected from the group consisting of a
polyisocyanate, epoxy resin and/or a. maleimide compound.
[0016] In a preferred embodiment, the adhesive comprises (i) at least one halogen-containing
polyolefin, preferably selected from the group consisting of chlorinated natural rubber and
chlorosulfonated polyethylene; (ii) from about 1 to about 200 parts by weight, per 100 parts by weight
of said polyolefin, of an aromatic nitroso compound ; (iii) from about 10 to about 120 parts by weight
per 100 parts by weight of said halogen- containing polyolefin of zinc phosphate ; (iv) fiom zero to
about 25 parts by weight, per 100 parts by weight of said halogen- containing polyolefin, of at least
one maleimide compound, polyisocyanate, epoxy resin and/or chlorinated dichlorobutadiene
polymer ; (v) from zero to about 40 parts by weight, per 100 parts by weight of said halogencontaining polyolefin, of a vulcanizing agent selected from the group consisting of sulfur and
selenium; (vi) an inert water or organic solvent diluent, said diluent being present in an amount to
provide a liquid composition suitable for use as an adhesive, said liquid adhesive having a
total solids content in the range from about 5 to about 80 percent.
[0017] The adhesive compositions of the invention are characterized by the unexpected ability to
provide strong vulcanized rubber-to-substrate bonds with durability and environmental resistance
without the need for priming the substrate surface. However, they can be used with convention
substrate primer compositions if one so desires. The compositions provide excellent adhesion for
both unvulcanized and vulcanized elastomer compositions, without the need to chlorinate the rubber
surface. In addition to affording one- coat adhesive systems characterized by excellent primary
adhesion and environmental resistance, the compositions of the invention exhibit excellent shelf-life
stability, resistance to in-mold sweep, provide ample pre-bake resistance, good layover
characteristics, and are effective over a broad spectrum of bonding temperatures, e. g., from about
90 C. to over 180 C.
DETAILED DESCRIPTION [0018] The vulcanizable rubber substrates bonded by the invention are
comprised of vulcanizable rubbers. These rubbers are formulated in numerous recipes, widely
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available and beyond the scope of this disclosure. Examples of the synthetic rubber used as
vulcanizable rubber herein include the following.
(1) Homopolymers of conjugated diene compound such as isoprene, butadiene, and chloroprene.
Examples include polyisoprene rubber (IR), polybutadiene rubber (BR), and polychloroprene rubber.
(2) Copolymers of said conjugated diene compound with a vinyl compound such as styrene,
acrylonitrile, vinylpyridine, acrylic acid, methacrylic acid, alkyl acrylate, and alkyl methacrylate.
Examples include styrene-butadiene copolymer rubber (SBR), vinylpyridine butadiene styrene
copolymer rubber, acrylonitrile butadiene copolymer rubber, acrylic acid butadiene copolymer
rubber, methacrylic acid butadiene copolymer rubber, methyl acrylate butadiene copolymer rubber,
and methyl methacrylate butadiene copolymer rubber.
(3) Copolymers of olefin (such as ethylene, propylene, and isobutylene) with diene compound.
Examples include isobutylene-isoprene copolymer rubber (IIR).
(4) Copolymers (EPDM) of olefin with non-conjugated diene. Examples include ethylene- propylenecyclopentadiene terpolymer, ethylene-propylene-5-ethylidene-2-norbornene terpolymer, and
ethylene-propylene-1, 4-hexadiene terpolymer, (5) Polyalkenamer obtained by ring opening
polymerization of cycloolefin. Examples include polypentenamer.
(6) Rubber obtained by ring opening polymerization of oxirane. Examples include
polyepichlorohydrin rubber vulcanizable with sulfur.
(7) Polypropylene oxide rubber.
[0019] Additional examples include their halides, such as chlorinated isobutylene-isoprene
copolymer rubber (Cl-IIR) and brominated isobutylene-isoprene copolymer rubber (Br-IIR).
Other examples include polymers obtained by ring opening polymerization of norbornene.
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The above-mentioned rubber may be blended with a saturated elastomer such as epichlorohydrin
rubber, polypropylene oxide rubber, and chlorosulfonated polyethylene.
[0020] Essential in the adhesive is a halogenated film former, such as halogen-containing polyolefin
film formers. These include natural or synthetic elastomers. The halogens employed in the
halogenated polyolefinic elastomers will usually be chlorine or bromine, although fluorine can also be
used. A combination of halogen atoms can also be employed in which case the halogen-containing
polyolefinic elastomer will have more than one halogen substituted thereon. The amount of halogen
does not appear critical and can range from as low as about 3 weight percent to more than 70
weight percent, depending on the nature of the base polymer. Halogen-containing polyolefinic
elastomers and their preparation are well Imown in the art and no need is seen to elucidate in any
detail on these materials or their
manufacture. Representative halogen-containing polyolefinic elastomers include, without being
limited thereto, chlorinated natural rubber, chlorine-and bromine-containing synthetic rubbers
including polychloroprene, chlorinated polychloroprene, chlorinated polybutadiene, chlorinated
butadiene styrene copolymers, chlorinated ethylene propylene copolymers and
ethylene/propylene/non-conjugated diene terpolymers, chlorinated polyethylene, chlorosulfonated
polyethylene, copolymers of a-chloroacrylonitrile and 2, 3-dichloro-1, 3buta. diene, chlorinated poly
(vinyl chloride), and the like, including mixtures of such halogencontaining elastomers. Thus,
substantially any of the known halogen-containing derivatives of natural and synthetic elastomers can
be employed in the practice of this invention, including mixtures of such elastomers.
Chlorosulfonated polyethylene elastomers alone or in combination with chlorinated rubber are the
most preferred halogen-containing film former.
Chlorosulfonated polyethylene containing 35%, and 43% (wt. ) of chlorine are commercially available
from E. 1. DuPont de Nemours & Co. under the HYPALON ; mark. Chlorinated natural rubber is
commercially available from Bayer Aktiengesellschaft, under the PERCTUT; mark, and LFE, Inc.
under the Aquaprene0 mark. A combination of chlorinated natural rubber and chlorosulfonated
polyethylene is a particularly beneficial film former. If chlorinated polyolefin (CPE) is employed as a
primary film former, the chlorine content should be greater than about 60 percent and the CPE
molecular weight greater than about 500. Such chlorine contents can be obtained by a process
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involving the dispersion and chlorination of high surface area. polyolefinic particles in an aqueous
medium taught in U. S.
Patent No. 5,534, 991.
[0021] A supplemental film former is used in some of the embodiments according to the invention.
These are based on a brominated polymer of 2, 3-dichloro-1, 3-butadiene; 1,3- butadiene ; 2, 3dibromo-1, 3-butadiene; isoprene ; 2,3-dimethylbutadiene ; chloroprene ; bromoprene; 2, 3-dibromo1, 3-butadiene ; 1,1, 2-trichlorobutadiene ; cyanoprene ; hexachlorobutadiene and combinations
thereof. It is particularly preferred to use 2,3dichloro-1, 3-butadiene as the monomer as a
homopolymer or copolymer wherein a major portion of the co-polymer contains repeating units from
2, 3-dichloro-1, 3-butadiene, "Copolymerizable monomers"herein refers to monomers which are
capable of undergoing copolymerization with the butadiene monomers described above. Typical
copolymerizable
monomers useful in the supplemental film former include a-haloacrylonitriles such as abromoacrylonitrile and a-chloroacrylonitrile; a, -unsaturated carboxylic acids such as acrylic,
methacrylic, 2-ethylacrylic, 2-propylacrylic, 2-butylacrylic and itaconic acids; alkyl- 2-haloacrylates
such as ethyl-2-chloroacrylate and ethyl-2-bromoacrylate; styrene ; styrene sulfonic acid; ahalostyrenes ; chlorostyrene; a-methylstyrene ; a-bromovinylketone ; vinylidene chloride; vinyl
toluenes ; vinylnaphthalenes ; vinyl ethers, esters, and ketones such as methyl vinyl ether, vinyl
acetate, and methyl vinyl ketone; esters, amides, and nitriles of acrylic and methacrylic acids such as
ethyl acrylate, methyl methacrylate, glycidyl acrylate, methacrylamide, and acrylonitrile; and
combinations of such monomers.
[0022] Preparation of brominated polydichlorobutadiene is well known and taught in U. S.
Pat. No. 2, 725, 373. Rubber-like products are obtained by bromination of allylic sites on
polydichlorobutadiene polymers with free bromine or with brominating agents, such as
Nbromosuccinimide (NBS) for example, in organic, preferably chlorinated solvents optionally inert to
bromine, for example in chloroform, tetrachloromethane, chlorobenzene or even benzene. For a
bromine content of 16 to 27% by weight, these thermoplastic rubber-like products are readily soluble
in typical solvents. The brominated polydichlorobutadiene polymers are incorporated either as a
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solvent solution in organic diluent embodiments, or for water-based diluents, incorporated by forming
a latex according to methods known in the art. The brominated polymer can be dissolved in a solvent,
a surfactant can be added with water to the solution, and a phase-inversion under high shear is
carried out, followed by removal of the organic solvent to obtain a latex having a total solids content
of from about 10 to 60, preferably 25 to 50 percent by weight. Solutions of copolymers of brominated
dichlorobutadiene in chlorinated aliphatic or aromatic solvents are readily prepared.
[0023] Alternatively, a latex polymer can also be prepared by emulsion polymerization of chlorinated
ethylenically unsaturated monomers via conventional emulsion polymerization process and
brominated in the aqueous phase without the disperse particles coagulating or precipitating,
according to U. S. Patent No. 5, 306, 740. A preferred protective colloid for the latex is polyvinyl
alcohol as described in more detail in U. S. Patent No. 6, 268, 422, incorporated herein by reference.
A 2,3-dichlorobutadiene : a-bromoacrylonitrile copolymer
(55-80 wt. %: 45-20%, respectively) with polyvinyl alcohol protective colloid is a preferred aqueous
dispersion for supplemental film formers in aqueous adhesive embodiments.
[0024] In one adhesive embodiment an aromatic nitroso compound is included with halogencontaining polyolefin film former, zinc phosphte or Zn/Al/phos. Another adhesive embodiment
comprises halogen-containing polyolefin film former, zinc phosphte or Zn/Al/phos, a nitroso
compound and one or more than one adhesion promoter specified below. The nitroso compound
can be any aromatic hydrocarbon, such as benzenes, naphthalenes, anthracenes, biphenyls, and
the like, containing at least two nitroso groups attached directly to non-adjacent ring carbon atoms.
More particularly, such nitroso compounds are described as poly-C-nitroso aromatic compounds
having from 1 to 3 aromatic nuclei, including fused aromatic nuclei, having from 2 to 6 nitroso groups
attached directly to non-adjacent nuclear carbon atoms. The nuclear hydrogen atoms of the aromatic
nucleus can be replaced by alkyl, alkoxy, cycloalkyl, aryl, aralkyl, alkaryl, arylamine, arylnitroso,
amino, halogen, and like groups. The presence of such substituents on the aromatic nuclei has little
effect on the activity of the poly-C-nitroso compounds in the present invention. As far as is presently
known, there is no limitation as to the character of the substituent, and such substituents can be
organic or inorganic in nature. Thus, where reference is made to"DNB", this collectively refers to polyC-nitroso or di-C-nitroso aromatic compound, benzenes, or naphthalenes, and is understood to
include both substituted and unsubstituted nitroso compounds, unless otherwise specified.
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[0025] The preferred poly-C-nitroso materials are the di-nitroso aromatic compounds, especially the
dinitrosobenzenes and dinitrosonaphthalenes, such as the meta-or para- dinitrosobenzenes and the
meta-or para-dinitrosonaphthalenes. Particularly preferred poly- C-nitroso compounds are
characterized by the formula (R) m-Ar- (NO) 2 wherein Ar is selected from the group consisting of
phenylene and naphthalene; R is a monovalent organic radical selected from the group consisting of
alkyl, cycloalkyl, aryl, aralkyl, alkaryl, arylamine and alkoxy radicals having from 1 to 20 carbon atoms,
amino, or halogen, and is preferably an alkyl group having from 1 to 8 carbon atoms ; and m is zero,
1,2, 3, or 4.
Preferably m is zero. DNB is incorporated into the adhesive composition by addition as a
solvent dispersion. The nitroso compound may be replaced by the corresponding oxime or the
corresponding nitro compound with the appropriate oxidation/reduction agent.
[0026] Exemplary non-limiting embodiments of poly-C-nitroso compounds which are suitable for use
in the practice of the invention include m-dinitrosobenzene, p- dinitrosobenzene, mdinitrosonaphthalene, p-dinitrosonaphthalene, 2,5-dinitroso-p-cymeme, 2-methyl-1, 4dinitrosobenzene, 2-methyl-5-chloro-1,4-dinitrosobenzene, 2-fluoro-1,4- dinitrosobenzene, 2methoxy-1-3-dinitrosobenzene, 5-chloro-1, 3-dinitrosobenzene, 2-benzyl- 1,4-dinitrobenzene, and 2cyclohexyl-1, 4-dinitrosobenzene. Amount of aromatic dinitroso compound used in the adhesive may
be from 1 to 200 parts by weight per 100 parts of halogenated polyolefin and preferably from 50 to
150 parts. Nitroso compounds are typically provided as 20-45wt. % dispsersion in aromatic or
chlorinated aromatic solvent.
[0027] Adhesives according to the preferred embodiments further comprise at least one adhesion
promoter, such as phenolic resin solutions, or dispersions, diisocyanates, polyisocyanates, epoxy
resins, and/or epoxy-phenolic resins which are known and commercially available. Generally from 1200 wt. parts of adhesion promoter is preferably present, per 100 wt. parts of halogen-containing film
former (PHR). Polyisocyanates include blocked polyisocyanate and an unblocked polyisocyanates
as aliphatic or cycloaliphatic polyisocyanates or adducts thereof. In especially preferred
embodiments, a water-dispersible isocyanate as an isocyanurate group containing-polyisocyanate
based on 1, 6-hexamethylene diisocyanate is selected. IN non-aqueous embodiments,
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polymethylene phenylisocyanate is preffered, [0028] The polyisocyanate in the adhesive composition
of the invention can be used in an amount of about 5% to about 55%, preferably 20 to 40%, more
preferably about 25 to about 35 percent by weight, based on the total weight of the solid
components of the composition.
Adhesive in a total solids content of from 20-50 wt. % can contain of di-, or poly-isocyanate from 1%
to 25%, preferably from 4%-20% by wt. On a PHR basis, the amount can range from 1 to 200 PHR on
100 wt. parts halogen-containing film former.
[0029] In embodiments utilizing a diluent (carrier) primarily of water, polyisocyana. tes should be
rendered more hydrophilic by chemically modifying the polyisocyanate structure to add a hydrophilic
group thereto, or by mixing the polyisocyanate with an external emulsifier, or both. Preferably the
polyisocyanate is rendered hydrophilic by the addition of the polyisocyanate with a non-ionic
ethylene oxide unit-containing polyether alcohol. When an external emulsifier is used, the emulsifier
also preferably is the reaction product of the polyisocyanate with a non-ionic ethylene oxide unitcontaining polyether alcohol as taught in U. S. Pat. No. 5,717, 031, incorporated herein by reference.
Exemplary polyisocyanates are 1, 4-diisocyana. tobutane, 1, 5-diisocyanato-2, 2-dimethylpentane, 2,
2, 4- and 2, 4, 4-trimethyl- 1, 6-diisocyanatohexane, 1,10-diisocyanatodecane, 4,4'-diisocyanatodicyclohexylmethane, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane-l,
3-diisocyanate, cyclohexane-1, 3- and/or 1,4-diisocyanate, 1-isocyanato-3, 3, 5-tlimethyl-5isocyanatomethyl cyclohexane (isophorone or IPDI). An exemplary hydrophilically modified
polyisocyanate compound is available from Bayer Inc. of Pittsburgh, Pa. , under the trade
designation Desmodur; and from Mobay Chemical Corporation under the designation Mondur (S.
Representative Desmodur (S compounds are described as a water-dispersible, solvent free
polyisocyanate based on hexamethylene diisocyanate (HDI) having a NCO content of 18.5 to 20.5%.
[0030] Another adhesion promoter is the class of phenolic resins that are suitable for inclusion in the
adhesives of the invention. Phenolic resins are well known compositions, and include water insoluble,
or water-dispersible resoles or novolaks. The resoles employed are normally base catalyzed resins
having a formaldehyde factor (i. e. , parts, by weight, of 40 weight percent aqueous formaldehyde
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per 100 parts by weight of unsubstituted phenol) of the order of about 90 to about 180. A novolak is
used in conjunction with formaldehye or a formaldehyde source, such as those known, and
described in U. S. Pat. No. 5,268, 404.
[0031] Phenolic resins are condensates of phenol, substituted phenols, or mixtures thereof and
aldehyde. Example starting materials include cresol, bisphenol-A, para-substituted phenols such as
para-t-butylphenol, para-phenylphenol, and the like. Ordinarily, formaldehyde or a material that
generates formaldehyde in situ is the aldehyde that is
employed to make the phenolic resin. Phenolics are dissolved in organic carrier in solvent- based
adhesive embodiments herein, or dispersed in water with aqueous adhesive embodiments herein.
[0032] A suitable phenolic resin for use in the invention is a resole produced by reacting
formaldehyde with bisphenol-A in a mol ratio of from about 2 to about 3.75 moles of formaldehyde
per mole of bisphenol-A, in the presence of a catalytic amount of an alkali metal or barium oxide or
hydroxide condensation catalyst, the reaction being carried out at elevated temperatures. The
condensation reaction product is then neutralized to a pH of from about 3 to about 8. An exemplary
novolak resin is para-substituted phenol such as para-t- butylphenol or para-phenyl-phenol
condensate with formaldehyde. Another exemplary phenolic is a novalak of a mixture of 20 percent
by weight of phenol and 80 percent by weight of t-butylphenol condensed with formaldehyde at a
formaldehyde factor of 50, in the presence of an acid catalyst. Another suitable phenolic resin for use
in the invention is a resole produced by reacting formaldehyde with bisphenol-A in a mol ratio of from
about 2 to about 3.75 moles of formaldehyde per mole of bisphenol-A, in the presence of a catalytic
amount of an alkali metal or barium oxide or hydroxide condensation catalyst, the reaction being
carried out at elevated temperatures. The condensation reaction product is then neutralized to a pH
of from about 3 to about 8.
[0033 The phenolic resin that is employed need not be pulverized or ground to a very fine particle
size, and it need not be dissolved in an organic solvent, prior to utilization in the process of the
invention in the preparation of the aqueous dispersion. A coupling solvent is preferably used, as
taught in U. S Pat. No. 5,268, 404, incorporated by reference. An exemplary coupling solvent such as
alcohols having a boiling point above 100 C, glycol ethers, ethers, and esters. Specific examples of
useful coupling solvents include ethanol, n- propanol, isopropyl alcohol, ethylene glycol monobutyl
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ether, ethylene glycol monoisobutyl ether, ethylene glycol monomethyl ether acetate, diethylene
glycol monobutyl ether, diethylene glycol monoethyl ether acetate, propylene glycol monopropyl
ether, methoxy acetone, and the like.
[0034] Phenolic resins are conventionally dispersed in water using a conventional colloidal protective
material. A preferred colloidal protective material is hydrolysed polyvinyl acetate, having a hydrolysis
level of 85 to 95 percent and viscosity at 4% solids in water of 4 to 25 mPa at 25'C. Exemplary
polyvinyl alcohol-stabilized phenolic resin dispersions are described in U. S. Pat. No. 4,124, 554,
incorporated herein by reference.
[0035] A particularly preferred aqueous dispersion of phenolic resin comprises a hydrophilic
phenolic resole, etherified bis-phenol having a. methylol functionality of from 1 to about 3. 5, and low
level of water-miscible solvent. Water miscible co-solvents include diethylene glycol butyl ether, 2butoxyethanol in an amount within the range from about 0. 01 wt % to about 10 wt. % of theresin
components. The etherified bis-phenol can be suitably employed on a solids basis in an amount of
from 10 wt. parts to 55 wt. parts with 90 to 45 wt. parts of a hydrophilic phenolic resole, as is used in
Example 2 below (phenolic dispersion). More preferably 20 wt. parts to 40 wt. parts of etherified bisphenol is combined with 80 to 60 wt. parts of the hydrophilic phenolic resole, cosolvent, and colloidal
protective additive. In a more preferred adhesive embodiment, chlorosulfonated polyethylene latex,
phenol- formaldehyde resole, butylated Bis A-formaldehyde adduct PVOH, an Zn/Al phosphate are
combined as a stable aqueous dispersion. Methods for preparing preferred phenolic aqueous
dispersions are disclosed in U. S. Pat. No. 5,548, 015, incorporated herein by reference.
[0036] Another suitable adhesion promoter is a maleimide compound. Maleimide can be used alone
with halogenated film former and zinc phosphate, or Zn/Al phosphate, or preferably in combination
with halogenated film former, a nitroso compound, and zinc phosphate, or Zn/Al phosphate metal
scavenger. Maleimide adhesion promoters include any of the maleimide, bis-or poly-maleimide and
related compounds such as are described in U. S. Pat. Nos. 2, 444,536 and 2,462, 835, incorporated
by reference. The maleimide compound used herein may be an aliphatic or aromatic polymaleimide
and must contain at least two maleimide groups. Preferred maleimide compounds include the N,
N'linked bismaleimides which are either joined directly at the nitrogen atoms without any intervening
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structure or in which the nitrogen atoms are joined to and separated by an intervening divalent
radical such as alkylene, cycloalkylene, oxydimethylene, phenylene (all 3 isomers),
2,6-dimethylene-4-alkyphenol, or sulfonyl, m-phenylene-bis-maleimide is a presently preferred
compound, and is available as"HVA-2"from E. I. du Pont de Nemours and Co., (Inc. ). Alternatively a
polymaleimide can be used, such as BMI-M-20 polymaleimide supplied by Mitsui Toatsu Fine
Chemicals, Incorporated. The amount of maleimide compound used in some embodiment adhesives
may be from 1 to 100 parts by weight per 100 parts (PHR) of halogen-containing polyolefin,
preferably 5 to 100 PHR, and more preferably 10 to 60 PHR. Particularly preferred polymaleimide
compounds have the formula :
wherein x is fiom about 1 to 100. Such polymaleimides are common materials of commerce and are
sold under different trade names by different companies. Amounts of maleimide typically range from
0 to 100 PHR, preferably 5 to 100 PHR, more preferably from 5 to 50 PHR of halogen-containing film
former.
[0037] Another adhesion promoter, acting also as an acid acceptor is the class of epoxy resins.
Preferred epoxy resins are polyglycidyl polyethers of polyhydric phenols, These phenolic-epoxy
resins are complex polymeric reaction products of polyhydric phenols with polyfunctional halohydrins
and/or glycerol dichlorohydrin. The products thus obtained contain terminal epoxy groups. A large
number of epoxy resins of this type are disclosed in Greenlee U. S. Pat. Nos. 2, 585,115 and 2, 589,
245. Several of these resins are available commercially. Suitable polyhydric phenols useful in the
preparation of the phenolic epoxy resins used herein include resorcinol and novolac resins resulting
from condensation of phenol with formaldehyde, The phenol/formaldehyde molar ratio, coupled with
the type of catalyst, determines whether the resulting polymer is phenol terminated or methylol
terminated; phenol-terminated are referred to as novolacs. These are produced from a
reaction mixture having a formaldehyde/phenol molar ratio between 0.5 and 0.8 in the presence of
an acid catalyst. Resorcinol is a very reactive dihydric phenol with formaldehyde, allowing for the
preparation of resorcinol-formaldehyde novolacs.
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[0038] Phenolic epoxy resins may be further characterized by reference of their epoxy weight of pure
epoxy resins being the mean molecular weight of the resin divided by the mean number of epoxy
radicals per molecule or in any case the number of grams of epoxy resin equivalent to one mole of
the epoxy group or one gram equivalent of epoxide. The phenolic epoxy resins that may be used in
the present invention have an epoxy equivalent weight of about 400-1000. Amount of epoxy resin,
such as phenolic epoxy, used in the adhesive may be from 0 to about 80 parts by weight per 100
parts by weight of said halogen- containing polyolefin, preferably from about 2 to about 80 PHR,
more preferably from 2 to 50 PHR.
[0039] Optional vulcanizing agents that are suitable for use in one-coat embodiments not used in
conjunction with metal primers, are sulfur and selenium. The vulcanizing agents are well known and
commercially available. An amount of vulcanizing agent in the adhesive composition may be from 0
to about 40 parts by weight per 100 parts of halogen-containing polyolefin, preferably 2 to 30 PHR,
and more preferably from 5 to 30 PHR.
[0040] If desired, the adhesive compositions of the invention can include conventional additives such
as inert filer material, like barium sulfate, polymeric film-forming adjuncts, pigments, solvent and the
like, with the amounts of such additions being within the range customarily employed. A particularly
preferred filler is carbon black and when utilized is incorporated in amounts ranging from 0 to 20%
by weight on a dry solids basis. Silicates, such as fumed silica, or hydrated silica are preferably used
at levels of 0.2 to 2% to total weight of adhesive.
[0041] An amount of metal scavenger comprising zinc phosphate, effective as replacement for lead
compounds is from 10 to 120 PHR, preferably 12 to 80 PHR. The phosphates as
phosphoric acid salts usable in the preparation of metal phosphate component are, for example,
aluminum phosphate, zinc phosphate, and aluminum dihydrogentripolyphosphate.
Aluminum dihydrogentripolyphosphate is particularly preferably used in the present invention. The
aluminum phosphates can be treated with the Zn compounds in conventional methods such as
follows. The treatment with a Zn compound can be effected after obtaining aluminum
dihydrogentripolyphosphate. As a treatment method, particles of aluminum
dihydrogentripolyphosphate are dispersed in a solution containing a Zn ion and the Zn ion is
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deposited as the hydroxide on the surface of the particles of aluminum dihydrogentripolyphosphate
by changing the pH of the solution from a weak acidic side to an alkaline side by amines. Thereafter,
the zinc hydroxide on the surface is converted to zinc oxide by filtering, washing with water, drying
and heat-treating. The substances capable of delivering a Zn ion for preparing a solution containing
a Zn ion include zinc chloride, zinc hydroxide, zinc nitrate, zinc carbonate, zinc sulfate etc,,
phosphates treated with Zn compounds, particularly, aluminum dihydrogentripolyphosphate can
provide excellent durability of adhesive properties.
[0042] Zn components are included in or coated on the particles of aluminum phosphate by, for
example, adsorption or absorption. The phosphates treated with Zn compounds can be used alone
or preferably in mixtures with aluminum and/or zinc oxides. A more preferred acid scavenger is a.
mixture of 25-35 wt. % zinc oxide, 25-35 wt. % zinc phosphate and 25-35 wt. % aluminum phosphate
(Zn/Al phos. ). The most preferred acid scavenger comprises zinc phosphate in a 1 : 1: 1 mixture of
zinc oxide, zinc phosphate and aluminum phosphate. Such mixtures are sold by Heubach Company.
[0043] The preferred embodiment includes a 20-50 parts of metal oxide such as zinc oxide in
combination with 100 parts of zinc phosphate. The amount of acid scavenger comprising zinc
phosphate present in the adhesive composition ranges from about 5 to about 120 parts by weight
per 100 parts of halogen-containing polyolefin (PHR), preferably from 10 to about 120 PHR, and
more preferably from 12 to 80 PHR.
[0044] The adhesive compositions of this invention are prepared by conventional means. For ease of
application, as is conventional in this art, the components will be mixed and dispersed in an inert
liquid diluents which, once the composition has been applied to the substrate, can be readily
evaporated. Examples of suitable liquid diluents are water, aromatic and halogenated aromatic
hydrocarbons such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, and the like;
halogenated aliphatic hydrocarbons such as trichloroethylene, perchloroethylene, propylene
dichloride and the like; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and the like;
ethers, naphthas, etc. , including mixtures of such carriers. Preferred diluents are xylene and toluene,
ortho-and para-chlorotoluene, optionally in combination with tetrachloroethylene. The amount of the
diluent employed is that which provides a. composition suitable for use as an adhesive. Typical
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diluent amount, by weight to total adhesive weight ranges from 20 to 4000 parts per hundred weight
parts of all halogen- containing film former (PHR). This amount will ordinarily be such as to provide a
total solids content ranging from about 5% to 80%, preferably about 15% to about 40% percent by
weight. In terms of preferred wt. Parts of diluent per 100 wt. parts of halogen-containing polyolefin,
the diluent can be used in an amount ranging from 200 to 1000 PHR of halogenated film former.
[0045] When water is used as a diluent, the finely divided solid components should be predispersed
using dispersing agent such as lignosulfonates including as a basic lignin monomer unit a
substituted phenyl propane. These are commercially available under the trade designation as
Marasperse; from Ligno Tech U. S. A. and water, which can assist in achieving a desirable uniform
aqueous coating of the adhesive on the substrate surface.
[0046] The adhesives herein may be coated on a primer or directly applied to the substrate.
The metal surface to which the elastomeric substrate is ultimately bonded to may optionally have a
conventional water-based or solvent-based metal primer applied thereto. Typical conventional waterbased primers include phenolic resin-type primers such as CHEMLOK 802, CHEMLOK 805,
CHEMLOK 8006, and CHEMLOK 8401 produced by Lord Corporation. Typical solvent-based
primers include phenolic resin-type primers such as CHEMLOK 205 or CHEMLOK 207 produced by
Lord Corporation. The adhesive
composition is typically applied directly to a metal surface or directly to any primer which has been
applied to the metal so as to ensure contact between the adhesive composition and the elastomeric
substrate which is brought into contact with the coated metal surface.
[0047] The adhesive compositions of the present invention have been found to be particularly useful
for bonding a wide variety of elastomeric materials, including both vulcanized and vulcanizable
elastomeric materials, to themselves or to other substrates, particularly to metal substrates.
Elastomers which can be bonded include without limitation natural rubber, polychloroprene rubber,
styrene-butadiene rubber, nitrile rubber, ethylene/propylene copolymer rubber (EPM);
ethylene/propylene/diene terpolymer rubber (EPDM); butyl rubber, polyurethane rubber, PAREL type
elastomers, and the like. Other substrates which can be effectively bonded to themselves or to
elastomers include fabrics such as fiberglass, polyamides, polyester, aramides, e. g. , Kevlar, a
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trademark of E. I. du Pont de Nemours Co. , (Inc.), of Wilmington, Del. , glass, ceramics and the like.
Metals and their alloys to which the elastomers can be bonded include steel, stainless steel, lead,
aluminum, copper, brass, bronze, Monel metals, nickel, zinc, and the like, including treated metals
such as phosphatized steel, galvanized steel, and the like.
[0048] The adhesive compositions are applied to substrate surfaces in a conventional manner such
as by dipping, spraying, brushing, and the like. Preferably, the substrate surfaces are allowed to dry
after coating before being brought together. After the surfaces have been pressed together with the
adhesive layer in between, the assembly is heated in accordance with conventional practices. The
exact conditions selected will depend upon the particular elastomer being bonded and whether or
not it is cured. If the rubber is uncured, the curing is to be effected during bonding, the conditions
will be dictated by the rubber composition and will generally be at a temperature of from about 140
C. to about 200 C. for from about 5 to about 60 minutes. If the rubber is already cured, the bonding
temperature may range from about 90 C. to above 180 C. for from 15 to about 120 minutes.
Alternatively, in situations where applicable, the adhesives can be interspersed between the surfaces
to be joined as a solid film or tape (100% TSC adhesive system) with bonding being accomplished
as before.
EXAMPLES [0049] The following examples are provided for purposes of illustrating the invention, it
being understood that the invention is not limited to the examples nor to the specific details therein
enumerated. In the examples, amounts are parts by weight, unless otherwise specified.
Metal coupons were treated with commercial primers A and B.. They were spray applied to zinc
phosphatized steel coupons at 0.30 mil dry film thickness (DFT). Adhesive was sprayed over dried
each primer at 0. 70 mil DFT. Adhesive was also used as a one coat (Ex. 1C) at 1. 0 mil DFT. The
elastomer used was a conventional natural rubber compound and was injection molded at 350 F/176
C for 11 minutes. Some parts where pre-baked prior to molding to evaluate the resistance to time
delays in typical manufacturing processes.
[0050] Primary Adhesion (PA) was measured in accordance with ASTM D429 Method B.
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Parts were destroyed on the 3 station United Tester at ambient, speed was 20"/min ; a 45 degree
angle. The maximum force required to remove the rubber or have the rubber stock break is recorded
along with the percent of rubber remaining on the part. A part having 100% rubber retention is the
best attainable adhesion failure mode.
[0051] Hot Tear (HT) testing is performed by placing part in an oven at 300 F for 15 minutes and
immediately destroying the part on the 3 station United Tester at a speed of 20"/minute ; a. 45
degree angle.
[0052] The boiling water (BW) test is performed by fastening the part in a fixture where the angle
from the bond line to the rubber tail is 45 degrees. The tail is fastened to a cable where a 5-pound
free weight is attached. The parts are immersed in this environment for a 2-hour duration. Parts are
removed from the fixture and allowed to cool to ambient. The parts are destroyed manually by
peeling the rubber from the substrate with needle nose pliers and the bond area is evaluated for
rubber retention.
[0053] Salt spray (SS) testing is performed by applying a constant stress to the bond line by pulling
the rubber tail and fastening the tail while the part is stressed. The part is then placed in a 5% salt
fog at 95 F for a 1-week period. Parts are destroyed as in the above peeling and evaluated the same
as the boiling water specimens.
[0054] The propylene glycol (PG) test is carried out by immersing stressed parts in a container of
propylene glycol and the container is closed and placed in an oven at 250 F for 5 days. Bonded
parts are evaluated the same manner as salt spray and boiling water.
Example 1 Masterbatch Dry weight
Raw Materials
Nitroso compound 7.12
Carbon Black 14. 25
Chlorinated NR 3.08 Zn/Al phos. 6.01
Xylene 56.568 Adhesive
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Raw Materials Wet Dry
Chlorinated NR 8.791 27.23
Epoxy resin 0.402 1. 38
Chlorinated NR 8.758 30. 2
BrominatedDCD 6. 211 10.71
Toluene 7.484 0
TSC: 29.00% [0055] In the Tables: PA = Primary Adhesion, at 0', 3'time of pre-bake ; HT = Hot Tear,
at 0', 3'-time of pre-bake ; BW = Boiling Water, 0', 3'-time of pre-bake ; SS = salt spray; Std. Dev. =
standard deviation.
Av. % R = average % rubber retained after peeling from the substrate.
EXAMPLE 1A-adhesive over commercial primer A Test PA-0'PA-3'HT-0'HT-3'BW-0'BW-3'
Comparative 100 100 100 100 98 98 Example 1 100 100 100 100 99 98
Example 1-A cont.
Test SS-0'SS-3'PG-0'PG-3'Avg % R Std. Dev.
Comparative 94 96 55 81 92. 2 14.3 Example 1 95 98 85 71 94.6 9. 5 Example 1B-adhesive over
commercial primer B Test PA-0'PA-3'HT-0'HT-3'BW-0'BW-3' Comparative 100 100 100 100 100 98
Example 1 100 84 100 80 100 74 Test SS-0'SS-3'PG-0'PG-3'Avg% R Std. Dev.
Comparative 100 100 85 100 98.3 4.7 Example 1 100 95 100 100 93.3 10.0 Example 1C-adhesive as
a one-coat Test PA-0'PA-3'HT-0'HT-3'BW-0'BW-3' Comparative 100 95 100 100 73 18 Example 1
100 100 100 100 44 29 Test SS-0'SS-3'PG-0'PG-3'Avg % R Std. dev.
Comparative 83 83 58 16 72.6 32.3 Example 1 93 73 61 16 71.6 32.4 Summary Data Avg % R STD
CH 256 87.7 14.0 Example 1 86.5 13.1
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[0056] EXAMPLE 2-comparison of acid scavengers
DRY PARTS OF RAW MATERIALS
CONT. A B C D E F G H I J K L
Phenolic dispersion 75 75 75 75 75 75 75 75 75 75 75 75 75
Chlorosulfonated 25 25 25 25 25 25 2 5 25 2 5 25 25 25 25
polyethylene
ZINC OXIDE 0 5 10 15
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DIBASIC LEAD 0 5 10 15
PHOSPHITE
Zn/Al Phos. 0 5 10 15
HYDROTALCITE 0 15 1
[0057] Substrate: Grit-blasted copper coupons Rubber: Commercial peroxide cured EPDM, cured
7.5 minutes at 340 F (171 C).
Adhesives : The adhesives were spray applied to provide approximately a 1.0 mils dry film thickness
and the bonding area was 1"x 1" (2.54 cm. X 2.54 cm. ) [0058] Environmental test: The bonded parts
were subjected to autoclave steam heat environment for 100 hours at 50 psi. The bonded parts were
then removed from the autoclave and were hand peeled with pliers to determine how much rubber
was retained on the 1 inch bond area. A percentage of rubber retained is then assigned after visual
inspection.
The parts were also either not baked or baked in an oven 5';340 F (171 C) prior to the molding cycle.
NOT BAKED BAKED 5'340 F
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Control Adhesive 15% RUBBER 85% RUBBER
A 40% RUBBER 40% RUBBER
B 8% RUBBER 2% RUBBER
C 75% RUBBER 50% RUBBER
D 1% RUBBER 10% RUBBER
E 8% RUBBER 8% RUBBER
F 0% RUBBER 2% RUBBER
G (invention) 85% RUBBER 97% RUBBER
H (invention) 43% RUBBER 100% RUBBER
I (invention) 98% RUBBER 100% RUBBER
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J 5% RUBBER 0% RUBBER
K 2% RUBBER 0% RUBBER
L 0% RUBBER 0% RUBBER
[0059] The improvement in rubber retention using a mixture of Zn/Al phos. in Examples F, G and H,
providing compared to zinc oxide alone, as taught in U. S. Pat. No. 5, 268, 404, and dibasic lead was
unexpected. Dibasic lead phosphite is recognized as the industry standard.
Bonds between rubber and metal using the formulation in accordance with the invention examples G,
H and I demonstrate excellent resistance to harsh environments.
[0060] Primary adhesion was evaluated between metal and EPDM using adhesives comprising 75 wt.
parts phenolic dispersion and levels for Zn/Al phos. and chlorosulfonated polyethylene indicated in
the following table. Bonded parts were pulled apart at 2" (5. 08 cm) per minute at a 45 angle at room
temperature. Percent rubber retained on the metal substrate is indicated in the following table:
Wt. Parts. 10 parts 15 parts 20 parts 25 parts
Zn/Al Phos. H alon 4500 Hypalon 4500 Hypalon 4500 Hypalon 4500
20 parts 100% Rubber 98% Rubber 100% Rubber 100% Rubber
15 parts 60% Rubber 75% Rubber 90% Rubber 100% Rubber
10 parts 85% Rubber 78% Rubber 88% Rubber 80% Rubber
0 parts 70% Rubber 5% Rubber 5% Rubber 48% Rubber
[0061] Excellent results are shown above for an adhesive consisting essentially of, on a weight basis,
from 60%-80 % of a phenolic resin., 8%-25% of chlorinated polyolefin and from 9%-25% of a mixture
of aluminum phosphate, zinc phosphate and zinc oxide.Claims:
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What is claimed is: 1. An adhesive composition containing less than 1000 ppm of lead, and
comprising (a) at least one diluent comprising water or organic solvent, (b) a halogen-containing
polyolefin, (c) optional nitroso compound, (d) an acid scavenger comprising zinc phosphate, and
optionally (e) an adhesion promoter.
2. The adhesive of claim 1 wherein said halogen-containing polyolefin is chlorosulfonated
polyethylene, said nitroso compound (c) is present and is a poly-C-nitroso compound, and said
adhesive further comprises carbon black, and silica.
3. The adhesive of claim 1 containing the following: (a) from 20 to 4000 PHR of said diluent, (b) 100
weight parts of said halogen-containing polyolefin ; (c) from 1 to 200 wt. parts 100 wt. parts of said
halogenated polyolefin (PHR), of said nitroso compound; (d) from 5 to 120 PHR of said acid
scavenger comprising zinc phosphate; (e) from 0 to 25 PHR, of said adhesion promoter.
4. The adhesive composition according to claim 1, wherein the halogen-containing polyolefin is
selected from the group consisting of chlorinated natural rubber, chlorosulfonated polyethylene,
chlorinated ethylene/propylene/non-conjugated diene terpolymers and mixtures thereof.
5. The adhesive composition according to claim wherein (b) is chlorinated natural rubber (c) is an
aromatic nitroso compound and further comprising a second halogencontaining polyolefin which is
brominated polydichlorobutadiene, and (e) a maleimide compound.
6. The adhesive composition according to claim 1 wherein (b) is a combination of chlorinated natural
rubber and chlorosulfonated polyethylene, (c) is an aromatic nitroso compound and (e) is a
polyisocyanate compound.
7. The adhesive composition according to claim 1 wherein the nitroso compound is an aromatic
nitroso compound present in an amount from 1 to 200 PHR, the said adhesion promoter is a
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maleimide compound present in an amount from 5 to 100 PHR, and said acid scavenger comprising
zinc phosphate is present in an amount from 10 to 120 PHR.
8. An adhesive composition according to claim 7 wherein the aromatic nitroso compound is present
in an amount from 50 to 150 PHR, the maleimide compound is present in an amount from 12 to 80
PHR and zinc phosphate is present in an amount from 12 to 80 PHR.
9. An adhesive composition according to claim 1 further comprising a vulcanizing agent selected
from the group consisting of sulfur and selenium.
10. An adhesive composition according to claim 9 wherein the vulcanizing agent is present in an
amount from 5 to 30 parts by weight per 100 parts by weight of halogen-containing polyolefin.
11. An adhesive composition according to claim 1 wherein (e) is selected from a phenolic resin
solution, a phenolic resin dispersion, and a phenolic epoxy resin.
12. An adhesive composition according to claim 11 wherein (e) is a novolak epoxy resin.
13. An adhesive composition according to claim 11 wherein the phenolic epoxy resin is present in an
amount from about 2 to 50 parts by weight per 100 parts by weight of halogencontaining polyolefin.
14. An adhesive composition comprising (a) from 20 to 4000 parts per 100 parts of (b) (PHR) of a
diluent, (b) 100 weight parts of at least one chlorinated natural rubber; (c) from 1 to about PHR of a
nitroso compound and 1 to 200 PHR of a brominated polydichlorobutadiene ; (d) from about 5 to
about 120 PHR of an acid scavenger comprising zinc phosphate; (e) from 1 to about 200 PHR, of an
adhesion promoter selected from the group consisting of a maleimide compound, phenolic resin,
epoxy resin, and a polyisocyanate, including mixtures thereof.
15. An adhesive composition comprising (a) from 20 to 4000 parts per 100 parts of (b) (PHR) of a
diluent, (b) 100 weight parts of at least one chlorosulfonated polyethylene; (c) from about 1 to 200
PHR of a nitroso compound and 1 to 200 PHR of a brominated polydichlorobutadiene ; (d) from 5 to
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about 120 PHR of an acid scavenger comprising zinc phosphate; (e) from 1 to 200 PHR, of an
adhesion promoter selected fiom the group consisting of a maleimide compound, a phenolic resin,
and epoxy resin, a polyisocyanate, and mixtures thereof.
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3. CN1366002 - 28.08.2002
CONDUCTIVE RUBBER COMPOSITION, CONDUCTIVE POLYMER COMPOSITION, CONDUCTIVE
VULCANIZED RUBBER, CONDUCTIVE RUBBER ROLLER AND CONDUCTIVE RUBBER BAND
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=CN1366002
Inventor(s):
TAKAYUKI HATTORI [JP] (--); TETSUO MIZOYUCHI [JP] (--)
Applicant(s):
SUMITOMO RUBBER IND [JP] (--)
IP Class 4 Digits: C08L; H01B
IP Class:
C8L63/00; H1B1/00
Application Number:
CN20020102325 (20020116)
Priority Number: JP20010009102 (20010117); JP20010025898 (20010201)
Family: CN1366002
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4. CN1386620 - 25.12.2002
METHOD AND APPARATUS FOR SEPARATING AND RECOVERING RUBBER AND STEEL PIPE
FROM STEEL PIPE WITH INTERNAL VULCANIZED RUBBER LINER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=CN1386620
Inventor(s):
LI BU [CN] (--); LIU YAOXIANG [CN] (--); DING HAI [CN] (--)
Applicant(s):
LI BU [CN] (--)
IP Class 4 Digits: B29B
IP Class:
B29B17/00
Application Number:
CN20020124821 (20020620)
Priority Number: CN20020124821 (20020620)
Family: CN1386620
Abstract:
A METHOD FOR RECOVERING THE RUBBER AND STEEL PIPE FROM THE STEEL PIPE WITH THE
VULCANIZED RUBBER LINING INCLUDES INDUCTION HEATING AT INDUSTRIAL FREQUENCY,
MF, OR HF FOR SEPARATING RUBBER FROM STEEL PIPE, CUTTING THE RUBBER TO BECOME
MORE BLOCKS BY MEANS OF SPECIAL CUTTER, AND COLLECTING THE RUBBER.
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5. DE10140774 - 13.03.2003
SHAPED HOSE FOR THE COOLING OR HEATING CIRCUIT OF AN INTERNAL COMBUSTION
ENGINE COMPRISES A KNITTED TEXTILE REINFORCEMENT MADE FROM HIGH-STRENGTH
POLYETHYLENE NAPHTHALATE YARN BETWEEN LAYERS OF VULCANIZED RUBBER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=DE10140774
Inventor(s):
GRAEFEN MELANIE (DE); LEDERER LEOPOLD (DE); WOHLFARTH LUTZ (DE)
Applicant(s):
METZELER AUTOMOTIVE PROFILE (DE)
IP Class 4 Digits: F16L; F01P
IP Class:
F16L11/04; F16L11/14; F1P11/04
E Class: F01P11/04; F16L11/08D
Application Number:
DE20011040774 (20010820)
Priority Number: DE20011040774 (20010820)
Family: DE10140774
Abstract:
SHAPED HOSE FOR THE COOLING OR HEATING CIRCUIT OF AN INTERNAL COMBUSTION
ENGINE COMPRISES A KNITTED TEXTILE REINFORCEMENT (12) MADE FROM HIGH-STRENGTH
POLYETHYLENE NAPHTHALATE YARN BETWEEN AN INNER LAYER (11) AND OUTER LAYER (13)
OF VULCANIZED RUBBER.Description:
Die Erfindung betrifft einen Formschlauch fьr den Kьhl- oder Heizkreislauf eines
Verbrennungsmotors, mit einer Innenlage aus einem vulkanisierbaren gummielastischen Material,
einer hierauf aufgebrachten Verstдrkungslage aus einem Textilgestrick und einer Aussenlage aus
einem vulkanisierbaren gummielastischen Material.
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Derartige Formschlдuche sind bekannt. Bei der Herstellung wird zunдchst ein Schlauch mit
Verstдrkungslage hergestellt. Nachfolgend wird der extrudierte Schlauch auf einen Dorn aufgezogen,
um die gewьnschte Formgebung des Schlauches zu erzielen. Anschliessend wird der Schlauch
vulkanisiert.
Die in dem Formschlauch vorgesehene Verstдrkungslage soll die Temperaturbestдndigkeit
insbesondere in dynamischer Hinsicht verbessern. Bekannt ist hierbei die Verwendung von
Textilgestricken aus unterschiedlichen Garntypen. Fьr schwefelvernetzte EPDM-Mischungen werden
beispielsweise Rayon-Garne eingesetzt. Fьr peroxidisch vernetzte Formschlдuche Aramid und auch
Polyester. Alle diese Garntypen haben verschiedene Vor- und Nachteile. So handelt es sich bei
Rayon um ein Naturprodukt, welches durch Witterung, Mikrofungi, Hitze und chemische Substanzen
beeinflusst wird. Darьber hinaus weist Rayon einen relativ hohen Schrumpf auf. Aramid-Garne sind
fьr den Einsatz als gestrickte Textileinlage in Formschlдuchen nicht fьr eine verbesserte Haftung
prдpariert. Polyester-Garne sind fьr schwefelvernetzte EPDM-Schlauchmischungen nicht
empfehlenswert.
Der Erfindung liegt die Aufgabe zugrunde, einen Formschlauch vorzuschlagen, der sich durch eine
verbesserte dynamische Temperaturstabilitдt und somit durch ein verbessertes Langzeitverhalten
auszeichnet.
Zur Lцsung dieser Aufgabe wird bei einem Formschlauch der eingangs genannten Art
vorgeschlagen, dass das Textilgestrick der Verstдrkungslage aus einem hochfesten
Polyethylennaphthalat(PEN)-Garn besteht.
Das erfindungsgemдss eingesetzte PEN-Gestrick fьhrt zu einer besseren dynamischen
Temperaturstabilitдt des Formschlauches. Darьber hinaus zeichnet sich der Formschlauch durch
eine hohe Festigkeit und geringen Schrumpf aus. Von Vorteil ist weiterhin, dass das verwendete
PEN- Garn eine sehr gute Haftung zu dem fьr die Innen- und Aussenlage verwendeten
vulkanisierbaren gummielastischen Material aufweist. Des weiteren ist die Bestдndigkeit gegenьber
Mischungsbestandteilen sehr hoch.
Vorteilhafte Weiterbildungen der Erfindung gehen aus den Unteransprьchen hervor.
41/425
Vorteilhaft weist das PEN-Garn eine Fadenstдrke (Titer) von 550 bis 2200 dtex auf. Hierbei variiert
die Fadenstдrke (Titer) mit dem Durchmesser des Formschlauches, der zwischen 6 bis 60 mm liegt.
In vorteilhafter Ausgestaltung weist das PEN-Garn einen Twist von 60 bis 120 t/m und/oder ein Modul
von 16 bis 29 N/tex auf.
Um die dynamische Temperaturbestдndigkeit zu erhцhen und insbesondere den Schrumpf
mцglichst gering zu halten, ist das PEN-Garn vorteilhaft vorzugsweise in einer Fadenstreckanlage
wдrmebehandelt. Hierdurch wird erreicht, dass ein Heissluftschrumpf bei 180 DEG C/15 min. von
3.5 bis 0.8 erzielt wird.
Um die Haftung des PEN-Garnes an dem gummielastischen Material zu verbessern, wird vorteilhaft
eine Haftungsaktivierung des PEN-Garnes vorgesehen, wobei dieses insbesondere einer RFLBehandlung unterzogen wird.
Vorteilhaft weist das Textilgewebe 7 bis 12 Stiche pro Zoll auf, wobei vorzugsweise der
Maschinenkopf einer Strickmaschine 8 bis 32 Nadeln aufweist. Durch diese Strickparameter wird
eine gute Durchgangshaftung der Innen- und Aussenlage des Formschlauches erzielt.
Als gummielastisches Material wird fьr die Innen- und Aussenlage vorteilhaft ein EPDM verwendet.
Nachfolgend wird die Erfindung anhand eines Ausfьhrungsbeispieles nдher erlдutert, das in
schematischer Weise in der Zeichnung dargestellt ist. Hierbei zeigen:
Fig. 1 eine Seitenansicht eines erfindungsgemдssen Formschlauches mit teilweise entfernter
Aussenlage beziehungsweise Verstдrkungslage;
Fig. 2 den Schnitt lдngs der Linie II-II in Fig. 1 und
Fig. 3 einen Lдngsschnitt durch den auf einen Dorn aufgezogenen Formschlauch gemдss Fig. 1.
Fig. 1 zeigt einen Formschlauch 10, der als Kьhlwasserschlauch bei einem Kraftfahrzeug zum
Einsatz kommt. Der konstruktive Aufbau des Formschlauches 10 ist sowohl aus Fig. 1 als auch aus
Fig. 2, die einen Schnitt lдngs der Linie II-II in Fig. 1 zeigt, ersichtlich.
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Der Formschlauch 10 weist eine Innenlage 11 aus EPDM auf, deren Innenseite eine das Kьhlwasser
fьhrende Innenцffnung 14 begrenzt. Auf die Aussenseite der Innenlage ist eine Verstдrkungslage
12 aufgebracht, die aus einem Textilgestrick besteht. Die Verstдrkungslage 12 ist von einer
Aussenlage 13 aus EPDM umgeben.
Das Textilgestrick der Verstдrkungslage 12 besteht aus einem Polyethylennaphthalat(PEN)-Garn,
das als Multifilamentfaser vorliegt. Das PEN-Garn weist abhдngig von dem Durchmesser des
Formschlauches 10 eine Fadenstдrke (Titer) von 550 bis 2200 dtex auf. Weiterhin ist eine RFLBehandlung (Resorcin-Formaldehyd-Latex) vorgesehen, um die Adhдsion mit dem fьr die Innenlage
11 und die Aussenlage 13 verwendeten EPDM zu verbessern. Darьber hinaus ist das PEN-Garn der
Verstдrkungslage 12 wдrmevorbehandelt, um einen Heissluftschrumpf bei 180 DEG C/15 min. von
3.5 bis 0.8 zu erzielen.
Das PEN-Garn wird zu einem Textilgestrick verarbeitet, das 7 bis 12 Stiche pro Zoll aufweist.
Hierdurch wird eine gute Durchgangshaftung mit dem EPDM-Werkstoff der Innenlage 11 und der
Aussenlage 13 erzielt.
Zur Herstellung des Formschlauches 10 wird zunдchst ein Extrudat hergestellt, bei dem die
gestrickte Verstдrkungslage 12 online gefertigt ist. Unter einer Online-Fertigung im Sinne der
vorliegenden Erfindung wird verstanden, dass zunдchst die Seele des Formschlauches extrudiert,
sodann das Gestrick und abschliessend die Decke hinzugefьgt wird. Nachfolgend wird der
extrudierte Schlauch auf einen die Formgebung bewirkenden Dorn 15 gezogen, wie in Fig. 3 zu
erkennen ist. Anschliessend wird eine Vulkanisation durchgefьhrt, um den fertigen Formschlauch 10
zu erhalten.
Durch die Verwendung eines Textilgestrickes aus hochfestem PEN- Garn wird eine hцhere
dynamische Temperaturstabilitдt und damit ein sehr gutes Langzeitverhalten des Formschlauches
10 erreicht. Weiterhin zeichnet sich das PEN-Garn durch eine gute Haftung auf EPDM- Werkstoff
aus.Claims:
1. Formschlauch fьr den Kьhl- oder Heizkreislauf eines Verbrennungsmotors, mit einer Innenlage
(11) aus einem vulkanisierbaren gummielastischen Material, einer hierauf aufgebrachten
Verstдrkungslage (12) aus einem Textilgestrick und einer Aussenlage (13) aus einem
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vulkanisierbaren gummielastischen Material, dadurch gekennzeichnet, dass das Textilgestrick der
Verstдrkungslage (12) aus einem hochfesten Polyethylennaphthalat(PEN)-Garn besteht.
2. Formschlauch nach Anspruch 1, dadurch gekennzeichnet, dass das PEN-Garn eine Fadenstдrke
(Titer) von 550 bis 2200 dtex aufweist.
3. Formschlauch nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass das PEN-Garn einen Twist
von 60 bis 120 t/m und/oder ein Modul von 16 bis 29 N/tex aufweist.
4. Formschlauch nach einem der Ansprьche 1 bis 3, dadurch gekennzeichnet, dass das PEN-Garn
wдrmevorbehandelt ist, um einen Heissluftschrumpf bei 180 DEG C/15 min. von 3.5 bis 0.8 zu
erzielen.
5. Formschlauch nach einem der Ansprьche 1 bis 4, dadurch gekennzeichnet, dass das PEN-Garn
zur Verbesserung der Haftung auf dem gummielastischen Material einer Haftungsaktivierung,
insbesondere einer RFL-Behandlung, unterzogen ist.
6. Formschlauch nach einem der Ansprьche 1 bis 5, dadurch gekennzeichnet, dass das
Textilgestrick 7 bis 12 Stiche pro Zoll vorzugsweise bei 8 bis 32 Nadeln pro Maschinenkopf einer
Strickmaschine aufweist.
7. Formschlauch nach einem der Ansprьche 1 bis 6, dadurch gekennzeichnet, dass als
gummielastisches Material ein EPDM verwendet wird.
44/425
6. DE10219735 - 07.08.2003
VULCANIZED SOLID RUBBER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=DE10219735
Inventor(s):
KOSHIBA JUNICHI (JP); NAKANO SADAYUKI (JP)
Applicant(s):
SUMITOMO CHEMICAL CO (US)
IP Class 4 Digits: C08F
IP Class:
C8F136/00
E Class: C08K5/01+L23/16; C08L23/16+B
Application Number:
US20020112704 (20020402)
Priority Number: JP20010162064 (20010530)
Family: DE10219735
Equivalent:
US6716931
Abstract:
THERE IS PROVIDED VULCANIZED SOLID RUBBER, WHICH COMPRISES A VULCANIZED
PRODUCT OF AN OIL-EXTENDED COPOLYMER COMPRISING: (I) 100 PARTS BY WEIGHT OF AN
ETHYLENE-ALPHA-OLEFIN-NON-CONJUGATED DIENE COPOLYMER SATISFYING THE
FOLLOWING REQUIREMENTS (1) TO (4), AND (II) 10 TO 90 PARTS BY WEIGHT OF AN EXTENDER
OIL: (1) A WEIGHT RATIO OF AN ETHYLENE UNIT TO AN ALPHA-OLEFIN UNIT IN THE ETHYLENEALPHA-OLEFIN-NON-CONJUGATED DIENE COPOLYMER IS FROM 73/27 TO 40/60, (2) AN IODINE
VALUE OF THE ETHYLENE-ALPHA-OLEFIN-NON-CONJUGATED DIENE COPOLYMER IS FROM 20
TO 36, (3) MOONEY VISCOSITY (ML1+4 (121 DEG C.)) MEASURED ACCORDING TO JIS-K-6300
OF A BLEND CONTAINING 100 PARTS BY WEIGHT OF THE ETHYLENE-ALPHA-OLEFIN-NONCONJUGATED DIENE COPOLYMER AND 20 PARTS BY WEIGHT OF AN EXTENDER OIL IS FROM
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100 TO 180, AND (4) A RATIO OF WEIGHT AVERAGE MOLECULAR CHAIN LENGTH/NUMBER
AVERAGE MOLECULAR CHAIN LENGTH MEASURED BY GEL PERMEATION CHROMATOGRAPHY
OF THE ETHYLENE-ALPHA-OLEFIN-NON-CONJUGATED DIENE COPOLYMER IS FROM 3 TO
5.Description:
FIELD OF THE INVENTION
[0001] The present invention relates to vulcanized solid rubber, which is superior in its long-term
compressive permanent strain; sealing efficiency; low-temperature characteristics; fatigue durability;
processability such as kneadability, extrudability and shape-retaining property; and its appearance.
The "solid rubber" means rubber having substantially no cell, and it is different from cellular rubber or
sponge.
BACKGROUND OF THE INVENTION
[0002] Most of vulcanized solid rubber used for applications such as a car have been produced by
vulcanizing ethylene-[alpha]-olefin-non-conjugated diene copolymer rubber superior in its heat
resistance, weather resistance, processability and cost. However, such vulcanized solid rubber
cannot satisfy the following requirements recently required for vulcanized solid rubber.
[0003] A problem such that a sound such as engine sound, wind-cutting sound around doors and
creaking sound of tires comes into a room during high-speed run of a car, and a problem of rainleaking depend largely upon sealing performance of doors and windows. Therefore, vulcanized solid
rubber having much more superior sealing efficiency has been desired. Particularly, materials such
as a door-sealing material, a window-sealing material and an engine mount are used under
compressed conditions for a long period of time, and therefore, vulcanized solid rubber having little
compressive permanent strain has been desired.
[0004] The compressive permanent strain can be improved by using such an ethylene-[alpha]-olefinnon-conjugated diene copolymer rubber having a high Mooney viscosity as a blend of 100 parts by
weight of the ethylene-[alpha]-olefin-non-conjugated diene copolymer rubber and 20 parts by weight
of an extender oil exceeds 100 of Mooney viscosity (ML1+4 (121[deg.] C.)). However, vulcanized
solid rubber obtained using such an ethylene-[alpha]-olefin-non-conjugated diene copolymer rubber
has problems of poor kneadability, formation of carbon aggregation lumps, surface roughening and
edge cutting of extrusion molded products, and surface roughening of die molded products.
[0005] Further, it is important that car doors and car windows can be opened and shut smoothly in a
wide temperature range of from a low temperature to a high temperature. Therefore, vulcanized solid
rubber capable of maintaining sufficient flexibility in a wide temperature range has been desired.
SUMMARY OF THE INVENTION
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[0006] An object of the present invention is to provide vulcanized solid rubber. which is superior in its
long-term compressive permanent strain; sealing efficiency; low-temperature characteristics; fatigue
durability; processability such as kneadability, extrudability and shape-retaining property; and its
appearance.
[0007] The present inventors have undertaken extensive studies of vulcanized solid rubber. As a
result, it has been fond that the above-mentioned object can be accomplished by using a
combination of an ethylene-[alpha]-olefin-non-conjugated diene copolymer having a high Mooney
viscosity and an extender oil. Thereby, the present invention has been obtained.
[0008] The present invention provides vulcanized solid rubber, which comprises a vulcanized
product of an oil-extended copolymer comprising:
[0009] (i) 100 parts by weight of an ethylene-[alpha]-olefin-non-conjugated diene copolymer
satisfying the following requirements (1) to (4), and
[0010] (ii) 10 to 90 parts by weight of an extender oil:
[0011] (1) a weight ratio of an ethylene unit to an [alpha]-olefin unit in the ethylene-[alpha]-olefin-nonconjugated diene copolymer is from 73/27 to 40/60,
[0012] (2) an iodine value of the ethylene-[alpha]-olefin-non-conjugated diene copolymer is from 20
to 36,
[0013] (3) Mooney viscosity (ML1-4 (121[deg.] C.)) measured according to JIS-K-6300 of a blend
containing 100 parts by weight of the ethylene-[alpha]-olefin-non-conjugated diene copolymer and
20 parts by weight of an extender oil is from 100 to 180, and
[0014] (4) a ratio of weight average molecular chain length/number average molecular chain length
measured by gel permeation chromatography of the ethylene-[alpha]-olefin-non-conjugated diene
copolymer is from 3 to 5.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Examples of the [alpha]-olefin of the ethylene-[alpha]-olefin-non-conjugated diene copolymer
contained in the oil-extended copolymer used in the present invention are propylene, 1-butene, 1pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. Of these, propylene and 1-butene
are preferred.
[0016] A weight ratio of an ethylene unit and an [alpha]-olefin unit, namely, ethylene unit/[alpha]olefin unit, in said copolymer is from 73/27 to 40/60, and preferably from 67/33 to 45/55. Here, the
"unit" means a polymerized monomer unit. For example, the "ethylene unit" means a polymerized
ethylene unit. When the ethylene unit exceeds 73 parts by weight, the vulcanized solid rubber
obtained may extremely deteriorate its compressive permanent strain at a low temperature. When the
ethylene unit is less than 40, dispersion of a reinforcing agent such as carbon black and inorganic
47/425
fillers in the vulcanized solid rubber obtained may be insufficient, thereby roughening a surface of
the solid rubber.
[0017] In the present invention, the "non-conjugated diene" of said copolymer means not only a nonconjugated diene but also a non-conjugated polyene such as a non-conjugated triene. Examples of
such compounds are linear non-conjugated dienes such as 1,4-hexadiene, 1,6-octadiene, 2-methyl1,5-hexadiene, 6-methyl-1,5-heptadiene and 7-methyl-1,6-octadiene; cyclic non-conjugated dienes
such as cyclohexadiene, dicyclopentadiene, methyltetraindene, 5-vinylnorbornene, 5-ethylidene-2norbornene and 6-chloromethyl-5-isopropenyl-2-norbornene; trienes such as 2,3-diisopropylidene-5norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 1,3,7octatriene and 1,4,9-decatriene; 5-vinyl-2-norbornene; 5-(2-propenyl)-2-norbornene; 5-(3-butenyl)-2norbornene; 5-(4-pentenyl)-2-norbornene; 5-(5-hexenyl)-2-norbornene; 5-(5-heptenyl)-2-norbornene;
5-(7-octenyl)-2-norbornene; 5-methylene-2-norbornene; 6,10-dimethyl-1,5,9-undecatriene; 5,9dimethyl-1,4,8-decatriene; 4-ethylidene-8-methyl-1,7-nonadiene; 13-ethyl-9-methyl-1,9,12pentadecatriene; 5,9,13-trimethyl-1,4,8,12-tetradecadiene; 8,14,16-trimethyl-1,7,14-hexadecatriene
and 4-ethylidene-12-methyl-1,11-pentadecadiene. These compounds may be used singly or in
combination of two or more. A preferred compound is 5-ethylidene-2-norbornene or
dicyclopentadiene or a combination of both.
[0018] An iodine value of the ethylene- a -olefin-non-conjugated diene copolymer contained in the
oil-extended copolymer is from 20 to 36, and preferably from 22 to 32. When the iodine value is less
than 20, the vulcanized solid rubber obtained may deteriorate its compressive permanent strain, or
decrease its vulcanization speed. In this regard, when a large amount of a vulcanization accelerator
is used in order to increase the vulcanization speed, the vulcanized solid rubber obtained may have
blooming. When the iodine value exceeds 36, flexibility of the vulcanized solid rubber obtained may
be insufficient.
[0019] Mooney viscosity of the ethylene-[alpha]-olefin-non-conjugated diene copolymer contained in
the oil-extended copolymer satisfies a requirement that Mooney viscosity (ML1+4 (121[deg.] C.))
measured according to JIS-K-6300 of a blend containing 100 parts by weight of said copolymer and
20 parts by weight of an extender oil is from 100 to 180, and preferably from 110 to 170. Here, the
reason why the Mooney viscosity is expressed not by the Mooney viscosity of said copolymer itself
but by that of the above-mentioned blend is as follows. In measuring Mooney viscosity of a
copolymer having Mooney viscosity as high as 200 or more, an inconvenience such as a slip occurs
between a torque-detecting rotor and the copolymer. Occurrence of such an inconvenience is
unavoidable from a structural viewpoint of a Mooney viscosity measurement apparatus. As a result, it
may be difficult to measure an accurate Mooney viscosity. When the Mooney viscosity is less than
100, it may be difficult to obtain vulcanized solid rubber having little compressive permanent strain,
48/425
or vulcanized solid rubber having good fatigue durability. When the Mooney viscosity exceeds 180, it
may be difficult to obtain vulcanized solid rubber having little quality variations. Incidentally, it is
desirable that Mooney viscosity of the copolymer itself exceeds 200.
[0020] A Q value, namely, weight average molecular chain length/number average molecular chain
length, measured according to gel permeation chromatography of the ethylene-[alpha]-olefin-nonconjugated diene copolymer contained in the oil-extended copolymer is from 3 to 5, and preferably
from 3 to 4. It is generally said that the Q value increases with increase of a molecular weight
distribution, and as a result, kneadability and extrudability can be improved. Whereas, in the present
invention, when the Q value exceeds 5, the molecular weight in a high molecular weight portion
further increases to make insufficient dispersion of a reinforcing agent such as carbon black and
inorganic fillers contained in the vulcanized solid rubber obtained. As a result, physical properties of
the vulcanized solid rubber may deteriorate. When the Q value is less than 3, kneading workability in
the production of the vulcanized solid rubber may deteriorate.
[0021] A process for producing the ethylene-[alpha]-olefin-non-conjugated diene copolymer
contained in the oil-extended copolymer is not particularly limited. It can be produced by a
conventional process using a conventional catalyst such as a titanium catalyst, a vanadium catalyst
and a metallocene catalyst.
[0022] The "extender oil" used in the present invention means a petroleum softening agent
conventionally used in the production of oil-extended rubber. Examples of the extender oil are
paraffin, naphthene and aromatic extender oils obtained by purifying high boiling fractions of
petroleum. These extender oils generally show a dynamic viscosity of from 5 to 35 mm/s at 100[deg.]
C.
[0023] The oil-extended copolymer used in the present invention is produced by a process wherein
the extender oil is blended wit the ethylene-[alpha]-olefin-non-conjugated copolymer during the
production step thereof, not by a process wherein the ethylene-[alpha]-olefin-non-conjugated diene
copolymer is once produced, and thereafter blended with the extender oil. More specifically, it is
produced by a process wherein the extender oil is blended with the ethylene-[alpha]-olefin-nonconjugated diene copolymer dissolved in a solvent in the production step thereof. The reason
therefor is that according to the latter process, it may result in failure to sufficiently blend the
copolymer with the extender oil because of a high Mooney viscosity of the ethylene-[alpha]-olefinnon-conjugated diene copolymer used in the present invention.
[0024] With respect to a blending proportion of the ethylene-[alpha]-olefin-non-conjugated diene
copolymer and the extender oil in the present invention, the extender oil is from 10 to 90 parts by
weight, and preferably from 20 to 80 parts by weight, per 100 parts by weight of said copolymer.
When the extender oil is less than 10 parts by weight, the vulcanized solid rubber obtained easily
49/425
causes problems of poor kneadability, formation of carbon aggregation lumps, surface roughening
and edge cutting of extrusion molded products, and surface roughening of die molded products.
The present invention has solved these problems by combining the ethylene-[alpha]-olefin-nonconjugated diene copolymer having a high Mooney viscosity and the extender oil. When the
extender oil exceeds 90 parts by weight, a viscosity of the blend comprising said copolymer and the
extender oil is too low to obtain sufficient dispersion of a reinforcing agent such as carbon black and
inorganic fillers in the vulcanized solid rubber obtained. As a result, the vulcanized solid rubber may
deteriorate its characteristics.
[0025] A process for producing the vulcanized solid rubber in accordance with the present invention
comprises, for example, the steps of (i) kneading a blend comprising the oil-extended copolymer, a
vulcanizing agent and, if necessary, the below-mentioned ingredient, with a conventional kneading
machine such as an open roll mill, a Banbury mixer, a kneader and an extruder to obtain a kneaded
product, and (ii) vulcanizing (cross-linking) the resulting kneaded product under heating.
[0026] Examples of the vulcanizing agent are sulfur; sulfur chloride; sulfur dichloride; 4,4'dithiodimorpholine; morpholine disulfide: alkylphenol disulfide; tetramethylthiuram disulfide; selenium
dimethyldithiocarbamate; and organic peroxides such as dicumyl peroxide, 2,5-dimethyl-2,5-di(tbutylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-(tbutylperoxy)hexyne-3, di-t-butylperoxide, di-t-butylperoxide-3,3,5-trimethylcyclohexane and tbutylhydroperoxide. Of these, preferred are sulfur, dicumyl peroxide, di-t-butylperoxide and tbutylperoxide-3,3,5-trimethylcyclohexane.
[0027] Sulfur is used in an amount of usually from 0.1 to 10 parts by weight, and preferably from 0.5
to 5 parts by weight, per 100 parts by weight of the ethylene-[alpha]-olefin-non-conjugated diene
copolymer. The organic peroxide is used in an amount of usually from 0.1 to 15 parts by weight, and
preferably from 0.5 to 8 parts by weight, per 100 parts by weight of said copolymer.
[0028] The vulcanizing agent may be used, if necessary, in combination with a vulcanization
accelerator and a vulcanization coagent. Examples of the vulcanization accelerator are N-cyclohexyl2-benzothiazole-sufenamide, N-oxydiethylene-2-benzothiazole-sulfenamide, N,N-diisopropyl-2benzothiazole-sulfenamide, 2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole,
2-(2,6-diethyl-4-morpholinothio)benzothiazole, dibenzothiazyl-disulfide, diphenylguanidine,
triphenylguanidine, di-o-tolylguanidine, o-tolyl-bi-guanide, diphenylguanidine-phthalate, an
acetaldehyde-aniline reaction product, a butylaldehyde-aniline condensate, hexamethylenetetramine,
acetaldehyde ammonia, 2-mercaptoimidazoline, thiocarbaniride, diethylthiourea, dibutylthiourea,
trimethylthiourea, di-o-tolylthiourea, tetramethylthiuram monosulfide, teramethylthiuram disulfide,
teraethylthiuram disulfide, terabutylthiuram disulfide, dipentamethylenethiuram tetrasulfide, zinc
dimethyldithiocarbamate, zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, zinc
50/425
ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithlocarbamate,
selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, zinc dibutylxanthate and
ethylenethiourea. The vulcanization accelerator is used in an amount of from 0.1 to 20 parts by
weight, and preferably from 0.2 to 10 parts by weight, per 100 parts by weight of the ethylene[alpha]-olefin-non-conjugated diene copolymer.
[0029] Examples of the vulcanization coagent are metal oxides such as magnesium oxide and zinc
oxide. Of these, preferred is zinc oxide. The vulcanization coagent is used usually in an amount of
from 3 to 20 parts by weight per 100 parts by weight of the ethylene-[alpha]-olefin-non-conjugated
diene copolymer.
[0030] When peroxides are used as the vulcanizing agent, examples of cross-linking coagent are
sulfur, quinonedioxime compounds such as p-quinonedioxime, polyethylene glycol dimethacrylate,
diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, ethylene dimethacrylate and divinylbenzene.
[0031] In producing the vulcanized solid rubber using the oil-extended copolymer and the
vulcanizing agent, if necessary, an ingredient such as plasticizers; fillers; resins such as, for example,
polyethylene and polypropylene; and rubber such as ethylene-[alpha]-olefin-non-conjugated diene
copolymers other than that mentioned above and different rubber may be incorporated.
[0032] The plasticizers may be those conventionally used for rubber. Examples thereof are process
oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, vaseline, coal tar pitch, caster oil,
linseed oil, factice, beeswax, ricinolic acid, palmitic acid, barium stearate, calcium stearate, zinc
laurate, atactic polypropylene and cumarone indene resin. Of these, particularly preferred is process
oil. The plasticizer is used in an amount of usually from 10 to 150 parts by weight, preferably from 30
to 150 parts by weight, and more preferably from 50 to 150 parts by weight, per 100 parts by weight
of the ethylene-[alpha]-olefin-non-conjugated diene copolymer. The amount can be determined from
a viewpoint of flexibility of the vulcanized solid rubber obtained.
[0033] Examples of preferred fillers are carbon black such as SRF, GPF, FEF, HAF, ISAF, SAF, FT
and MT, and inorganic fillers such as pulverized silicic acid, calcium carbonate, talc and clay, which
are conventionally used for rubber.
[0034] The vulcanized solid rubber in accordance with the present invention can be used the most
suitably for rubber vibration insulator such as an engine mount and a muffler hunger.
EXAMPLE
[0035] The present invention is illustrated in detail with reference to the following Examples, which
are not intended to limit the scope of the present invention.
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Comparative Examples 1 to 3 and Examples 1 to 6
[0036] Extender oil-extended copolymers or non-extended copolymers A to I used in these
Comparative Examples and Examples are as shown in Table 1.
[0037] The oil-extended copolymers or non-extended copolymers, process oil, carbon black,
calcium carbonate, stearic acid and zinc oxide, which are some of ingredients shown in Table 2,
were kneaded in respective proportions (parts by weight) as shown in Table 2 with a Banbury mixer
having a 1.5 l inner volume.
[0038] Successively, the resulting kneaded products were kneaded with "Mixture of other
compounds 1", which is as shown in Table 2, using an 8-inch open roll, thereby obtaining respective
non-vulcanized compositions. Here, the proportion of the above-mentioned process oil was
controlled so as to make respective Mooney viscosities (Table 3) of the non-vulcanized compositions
almost the same, so that processing conditions such as an extrusion condition applied for the nonvulcanized compositions were made equal.
[0039] The non-vulcanized composition obtained was extrusion-molded using a 45 mm extruder
mounted with ribbon dies having 20 mm width and 2 mm thickness at a dies temperature of 80[deg.]
C. and a cylinder temperature of 60[deg.] C. to obtain a ribbon-like article, and thereafter,
appearance of the surface (evenness of the surface) of the ribbon-like article was visually judged.
The results are as shown in Table 3.
[0040] The above-mentioned non-vulcanized composition was vulcanized in a mold at 160[deg.] C.
for 25 minutes, thereby obtaining a sample for measuring its compressive permanent strain. Using a
test piece prepared from the sample, its compressive permanent strain was measured according to
JIS K 6262 under conditions of a compressive rate of the test piece=25%, a test
temperature=70[deg.] C., and a test time=200 hours. The results are as shown in Table 3.
[0041] Gel permeation chromatography (GPC) measurement conditions for measuring Q values were
as follows.
[0042] 1. GPC Apparatus: GPC apparatus, a trade name of Type 150C-PLUS, manufactured by
Waters Co.
[0043] 2. Column: two columns, a trade name of TSK-GEL GMHHR-H(S), manufactured by Tosoh
Corporation, were used.
[0044] 3. Amount of sample: 300 [mu]l (polymer concentration=0.1% by weight)
[0045] 4. Flow rate: 1 ml/min.
[0046] 5. Temperature: 140[deg.] C.
[0047] 6. Solvent: o-dichlorobenzene
[0048] 7. Calibration curve: prepared by a conventional method using standard polystyrenes
manufactured by Tosoh Corporation.
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[0049] Table 3 summarizes as follows.
[0050] 1. Each of Examples 1 to 6 demonstrates that appearance of the ribbon-like article obtained
by extruding the non-vulcanized composition is good.
[0051] 2. Each of Examples 1 to 6 demonstrates that compressive permanent strain of the vulcanized
solid rubber is little.
[0052] 3. Each of Comparative Examples 1 and 2 demonstrates that appearance is good, but
compressive permanent strain of the vulcanized solid rubber is large.
[0053] 4. Comparative Example 3 demonstrates that compressive permanent strain of the vulcanized
solid rubber is little, but appearance is bad.
Comparative Example 4 and Example 7
[0054] Extender oil-extended copolymer B used in Comparative Example 4, and extender oilextended copolymer J used in Example 7 are as shown in Table 1.
[0055] Respective non-vulcanized compositions were obtained by the same kneading method as
mentioned above, except that ingredients as shown in Table 2 were used in respective proportions
(parts by weight) as shown in Table 2.
[0056] The non-vulcanized composition was vulcanized in a mold at 160[deg.] C. for 25 minutes,
thereby obtaining a sample for measuring its compressive permanent strain and a sample for
measuring its fatigue durability.
[0057] The compressive permanent strain was measured according to JIS K 6262 under conditions
of a compressive rate of the test piece of 25%, a test temperature of 120[deg.] C., and a test time of
70 hours. The results are as shown in Table 3.
[0058] The fatigue durability was measured by a method consisting of the steps of:
[0059] (i) stretching repeatedly a dumbbell No. 3 test piece in compliance with JIS K 6251 with a
fixed load fatigue tester, a trade name of NRF-08S, manufactured by Yoshimidzu Co., under
conditions of an atmospheric temperature of 80[deg.] C., a load of 0.1 to 1.9 kg and a frequency of
300 cpm, until the test piece has been broken, and
[0060] (ii) measuring stretch-repeat numbers.
[0061] The results are as shown in Table 3. Table 3 summarizes as follows.
[0062] 1. Example 7 demonstrates that compressive permanent strain of the vulcanized solid rubber
is little, and fatigue durability thereof is good.
[0063] 2. Comparative Example 4 demonstrates that compressive permanent strain of the vulcanized
solid rubber is large, and fatigue durability thereof is insufficient.
TABLE 1
Extender oil-extended or non-extended ethylene-propylene-ethylidene
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norbornene copolymer used in Comparative Examples and Examples
ABCDEFGHIJ
Content of extender oil (part by weight)*020020304020404030
Ethylene unit/propylene unit (by weight)60/4060/4060/4060/4060/4060/4060/4060/4060/4060/40
Iodine value22222424242428242428
Q value3.53.53.43.43.43.43.33.94.83.3
Content of extender oil = 0 part by weight165165-------Content of extender oil = 20 part by weight8585103103103103123105102123
Content of extender oil = 30 part by weight--81818181---103
Content of extender oil = 40 part by weight--64646464-65 63 *Content per 100 parts by weight of ethylene-propylene-ethylidene norbornene copolymer.
*Content per 100 parts by weight of ethylene-propylene-ethylidene norbornene copolymer.
[0064]
TABLE 2
ExampleExample
12341234567
Copolymer used (see Table 1)ABCBDEFGHIJ
Ratio of component for making non-vulcanized composition (part by weight)
Above-mentioned copolymer100120100120120130140120140140130
Process oil*95751054085756590656530
Carbon black*7575756075757575757560
Calcium carbonate202020-202020202020Stearic acid11111111111
Zinc oxide55555555555
Mixture of other compounds 1*8.98.98.9-8.98.98.98.98.98.9Mixture of other compounds 2*---9------9
*Process oil produced by Idemitsu Kosan Co., Ltd. (trademark: PW90).
*Carbon black produced by Asahi Carbon Co., Ltd. (trademark: ASAHI 50HG).
*The mixture consisting of 2 parts by weight of calcium oxide, 1.2 parts by weight of sulfur, 5.1 parts
by weight of a vulcanization accelerator, which accelerator is a blend of 1.5 parts by weight of 2mercapto-benzothiazole, 1.0 part by weight of zinc di-n-butyl dithiocarbamate, 0.7 part by weight of
dipentamethylenethiuram tetrasulfide, 1.5 parts by weight of ethylene-thiourea and 0.4 part by weight
of zinc dimethyl
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# dithiocarbamate, and 0.6 part by weight of morpholine disulfide (trade-mark: VULNOC R)
produced by Ouchishinko Chemical Industrial Co., Ltd.
*The mixture consisting of 7 parts by weight of dicumyl peroxide (trademark: PERCUMYL D-40)
produced by NOF Co., 1.5 parts by weight of ethylene glycol dimethacrylate and 0.5 parts by weight
of sulfur.
[0065]
TABLE 3
Comparative ExampleExample
12341234567
Mooney viscosity (ML1+4100[deg.] C.) of non-vulcan-38 37 38 50 37 37 38 39 38 37 6
ized composition
Appearance of ribbon-like article obtainedgoodgoodbad-goodgoodgoodgoodgoodslightly
by extruding above non-vulcanized composi-good
tion
Compressive permanent strain (%) of vulcan-19.219.416.820.616.616.516.915.116.616.716
ized solid rubber obtained by vulcanizing
above non-vulcanized composition
Fatigue durability of vulcanized solid rubber---15 *------58
obtained by vulcanizing above non-vulcan-1010
izedcompositionClaims:
1. Vulcanized solid rubber, which comprises a vulcanized product of an oil-extended copolymer
comprising:
(i) 100 parts by weight of an ethylene-[alpha]-olefin-non-conjugated diene copolymer satisfying the
following requirements (1) to (4), and
(ii) 10 to 90 parts by weight of an extender oil:
(1) a weight ratio of an ethylene unit to an [alpha]-olefin unit in the ethylene-[alpha]-olefin-nonconjugated diene copolymer is from 73/27 to 40/60,
(2) an iodine value of the ethylene-[alpha]-olefin-non-conjugated diene copolymer is from 20 to 36,
(3) Mooney viscosity (ML1+4 (121[deg.] C.)) measured according to JIS-K-6300 of a blend
containing 100 parts by weight of the ethylene-[alpha]-olefin-non-conjugated diene copolymer and
20 parts by weight of an extender oil Is from 100 to 180, and
(4) a ratio of weight average molecular chain length/number average molecular chain length
measured by gel permeation chromatography of the ethylene-[alpha]-olefin-non-conjugated diene
copolymer is from 3 to 5.
55/425
2. The vulcanized solid rubber according to claim 1, wherein a weight ratio of an ethylene unit to an
[alpha]-olefin unit in the ethylene-[alpha]-olefin-non-conjugated diene copolymer is from 67/33 to
45/55.
3. The vulcanized solid rubber according to claim 1, wherein an iodine value of the ethylene-[alpha]olefin-non-conjugated diene copolymer is from 22 to 32.
4. The vulcanized solid rubber according to claim 1, wherein the [alpha]-olefin in the ethylene[alpha]-olefin-non-conjugated diene copolymer contains propylene.
5. The vulcanized solid rubber according to claim 1, wherein the non-conjugated diene in the
ethylene-[alpha]-olefin-non-conjugated diene copolymer contains 5-ethylidene-2-norbornene or
dicyclopentadiene or a combination thereof.
6. Rubber vibration insulator comprising the vulcanized solid rubber according to claim 1.
7. An engine mount comprising the vulcanized solid rubber according to claim 1.
8. A muffler hanger comprising the vulcanized solid rubber according to claim 1.
9. A process for producing vulcanized solid rubber, which comprises the step of vulcanizing under
heating a blend comprising:
(i) an oil-extended copolymer, and
(ii) a vulcanizing agent,
the oil-extended copolymer containing:
(a) 100 parts by weight of an ethylene-[alpha]-olefin-non-conjugated diene copolymer satisfying the
following requirements (1) to (4), and
(b) 10 to 90 parts by weight of an extender oil,
(1) a weight ratio of an ethylene unit to an a-olefin unit in the ethylene-[alpha]-olefin-non-conjugated
diene copolymer is from 73/27 to 40/60,
(2) an iodine value of the ethylene-[alpha]-olefin-non-conjugated diene copolymer is from 20 to 36,
(3) Mooney viscosity (ML1+4 (121[deg.] C.)) measured according to JIS-K-6300 of a blend
containing 100 parts by weight of the ethylene-[alpha]-olefin-non-conjugated diene copolymer and
20 parts by weight of an extender oil is from 100 to 180, and
56/425
(4) a ratio of weight average molecular chain length/number average molecular chain length
measured by gel permeation chromatography of the ethylene-[alpha]-olefin-non-conjugated diene
copolymer is from 3 to 5.
57/425
7. DE10220308 - 18.12.2003
BICYCLE EMERGENCY LIGHTING USES ELECTROLUMINESCENT CORD OR
ELECTROLUMINESCENT STRIP LIGHT SOURCES VULCANIZED IN SURFACE OF RUBBER
BICYCLE TIRE
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=DE10220308
Inventor(s):
PUKALLUS ANDRE [DE] (--)
Applicant(s):
PUKALLUS ANDRE [DE] (--)
IP Class 4 Digits: B29D; B62J; B60C; F21S; F21V; B60Q; F21Y
IP Class:
F21Y103/00
B62J6/00; B60C19/00; B29D30/00; F21S8/10; F21S9/04; F21V19/00; B60Q1/26;
E Class: B60C13/00B
Application Number:
DE20021020308 (20020507)
Priority Number: DE20021020308 (20020507)
Family: DE10220308
Abstract:
THE EMERGENCY LIGHTING USES LIGHT SOURCES (1,1.2) WHICH ARE VULCANIZED WITHIN
THE SURFACE (3) OF A RUBBER BICYCLE TIRE, IN THE FORM OF AN ELECTROLUMINESCENT
CORD OR AN ELECTROLUMINESCENT FOIL STRIP, SUPPLIED WITH CURRENT VIA INSULATED
BICYCLE SPOKES FROM A HUB DYNAMO, OR VIA COILS (11) VULCANIZED WITHIN THE TIRE
SIDEWALLS AND COOPERATING PERMANENT MAGNETS (9).Description:
58/425
Jahrelang ist zu beobachten, dass viele Jugendliche und Kinder aber auch Erwachsene keine oder
nur teilweise beleuchtete Fahrrдder benutzen. Entweder ist die Beleuchtung defekt oder der
Kraftaufwand des summenden Dynamos stцrt.
Laut statistisches Bundesamt waren durch fehlende oder unzureichende Fahrradbeleuchtung
Columns=2>
zu beklagen.
In der DE 200 15 506 U1 ist eine Beleuchtungsvorrichtung fьr Inline-Skates, Roller-Skates, Tretroller
und Fahrrдder offenbart.
Bei dieser Beleuchtungsvorrichtung sind im Laufrad Leuchtdioden und Spulen eingebettet bzw.
eingegossen. Die ausserhalb des Laufrades angebrachten Magneten erzeugen in den Spulen Strom,
der die Leuchtdioden zum leuchten bringt.
Der im Patentanspruch 1 angegebenen Erfindung liegt das Problem zugrunde, Verkehrsunfдlle auf
Grund unzureichender oder fehlender Beleuchtung zu verringern und die Bequemlichkeit vor allem
bei Jugendlichen zu umgehen.
Dieses Problem wird durch die im Patentanspruch 1 aufgefьhrten Merkmale gelцst.
Der Vorteil dieser Erfindung ist ein Fahrradnotlicht, das nicht abschaltbar ist, das keine Kabel
vorhanden sind, das nicht Stцranfдllig ist und das bei Dunkelheit von vorne, von hinten und beiden
Seiten sichtbar ist.
Im Fahrradreifen sind mehrere Leuchtstreifen in den Profilrillen einvulkanisiert, die durch drehen des
Rades leuchten. Diese rotierenden Leuchtstreifen sind bis 200 Meter sichtbar und sofort als Fahrrad
erkennbar. Bei der zunehmenden Haus- und Gartenbeleuchtung vor allem zur Weihnachtszeit, geht
das normale Fahrradrьcklicht fцrmlich unter.
Es handelt sich um ein Notlicht, der Sinn ist "gesehen werden". Es kann nicht die herkцmmliche
Fahrradbeleuchtung ersetzen, aber vielleicht zur Vorschrift werden.
59/425
Dieses Notlicht ist vor allem fьr Jugendliche gedacht, die etwas Neues nur gut finden, wenn es cool
aussieht. Diese drehenden Leuchtstreifen kцnnten diese Erwartungen erfьllen.
Ein Ausfьhrungsbeispiel der Erfindung ist in der Zeichnung 1 und 2 dargestellt und wird im
Folgenden nдher beschrieben.
Es zeigen
Zeichnung 1
Bild 1 Vorderrad mit 12 Leuchtstreifen
Zeichnung 2
Bild 2 Reifen Draufsicht mit 3 verschiedenen Ausfьhrungen der Leuchtstreifen
Bild 3 Rad Seitenansicht
Zeichnung 3
Bild 4 Rad Seitenansicht Stromerzeugerspulen
Bild 5 Reifen Draufsicht Stromerzeugerspulen
Bild 6 Reifen Schnitt Dauermagneten
Die in Bild 2 abgebildeten Leuchtstreifen (1-1.2) sind aus Elektrolumineszenz-Schnur, oder aus
Elektrolumineszenz-Folie. Die Leuchtstreifen sind in den Profilrillen in der Gummi-Oberflдche (3)
einvulkanisiert und kцnnen dem Profil (2) angepasst werden (siehe Bild 2).
Transparente Profiloberflдche (дhnliches Gummi wie Inlinerrollen) vereinfacht die Herstellung. Die
Elektrolumineszenz Leuchtstreifen sind eine Kaltlichtquelle, die durch ein sich дnderndes,
elektrisches Feld eine Phosphorschicht zum leuchten anregt.
Technische Daten
Betriebsspannungsbereich: 60-110 V tilde&
Stromaufnahme Folie 50 cm x 0.2 mm: 13 mA
Stromaufnahme Schnur 1 m x 2 mm: 6 mA
Arbeitsfrequenzbereich: 50 bis 3000 Hz
Arbeitstemperaturbereich: -50 bis + 65 DEG C
60/425
Leuchtdauer: 25000 Stunden
Die Spannungsversorgung erfolgt durch ein 60 V Narbendynamo, oder ein 6 V Narbendynamo mit
nachgeschaltetem Inverter, ьber isolierte Speichen (8) zur Felge (5). An der Felgeninnenwand
ьbertragen Kontaktstreifen die Spannung ьber die Kontaktpunkte (7) an den Reifen. Die
Verdrahtung (6) der Leuchtstreifen ist im Reifenunterbau (4) einvulkanisiert. Die Vorder- und
Hinterradbeleuchtung ist identisch aufgebaut.
Eine weitere Mцglichkeit der Spannungsversorgung ist in der Zeichnung 3 dargestellt. In den
Reifenseitenwдnden sind beidseitig Spulen (11) in der gesamten Seitenwand einvulkanisiert, die
durch dicht an der Reifenaussenwand angeordneten Dauermagneten (9) Spannung erzeugen. Die
Spulen (11) sind in Bild 4 und 5 nur teilweise abgebildet. In Bild 6 ist der Reifen (12) als Schnitt
dargestellt und die beidseitig dicht an der Reifenseitenwand angeordneten Dauermagneten (9). Die
Halterung (10) eines Dauermagneten (9) ist in Bild 4 dargestellt.
Die relativ hohe Arbeitsspannung von 60-80 V tilde& bei der minimalen Stromstдrke von 20 mA ist
unbedenklich, ausserdem sind die Leuchtstreifen in einem isolierten transparentem Gummischlauch
einvulkanisiert. Die Spannung ist nur vorhanden, wenn sich das Rad dreht, das dann schon auf
Grund der Rotation nicht berьhrt werden sollte.
Bezugszeichenliste
1 Leuchtstreifen Standard
1.1 Leuchtstreifen Profilangepasst
1.2 Leuchtstreifen Unterbrochen
2 Profil
3 Gummi-Oberflдche
4 Reifenunterbau
5 Felge
6 Verdrahtung
7 Kontaktpunkt
8 Speiche
9 Dauermagnet
10 Magnethalterung
11 Stromerzeugerspulen
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12 Schnitt Reifen
Claims:
1. Notbeleuchtung fьr ein Fahrrad, mit Leuchtmitteln (1, 1.1, 1.2), die im Fahrradreifen einvulkanisiert
sind, dadurch gekennzeichnet, dass als Leuchtmittel (1, 1.1, 1.2) Elektrolumineszenz-Schnьre oder
Elektrolumineszenz- Folienstreifen verwendet werden, die ьber isolierte Speichen (8) mit Strom
gespeist werden, der von einem Nabendynamo erzeugt wird.
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8. DE10236295 - 25.03.2004
SHAFT COUPLING WITH HIGH TORSIONAL ELASTICITY AND METHOD OF MAKING SAME
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=DE10236295
Inventor(s):
KIRSCHEY GERHARD [DE] (--)
Applicant(s):
KIRSCHEY CENTA ANTRIEBE [US] (--)
IP Class 4 Digits: F16D
IP Class:
F16D3/52
E Class: F16D3/74
Application Number:
US20030636969 (20030807)
Priority Number: DE20021036295 (20020808)
Family: DE10236295
Equivalent:
CN1485553
Abstract:
AN ELASTIC SHAFT COUPLING WITH HIGH TORSIONAL ELASTICITY HAVING SEGMENTS
FORMED BY STEEL SHEET SEGMENT PLATES VULCANIZED TO AN ELASTOMERIC BODY AND IN
WHICH BLOCKING ELEMENTS BRIDGE THE RADIAL GAPS OF THE SEGMENTS OF EACH
COUPLING HALF SO AS TO BRACE THE PLATE SEGMENTS AGAINST AXIAL DEFORMATION. ALL
OF THE ELASTOMERIC BODIES ARE VULCANIZED TO THE SEGMENTS OR TO RINGS FROM
WHICH SEGMENTS ARE DIVIDED IN A COMMON VULCANIZATION PROCEDURE.Description:
FIELD OF THE INVENTION
[0001] My present invention relates to a shaft coupling with high torsional elasticity and to a method
of making such a shaft coupling. More particularly, the invention deals with high elasticity shaft
couplings for connecting a driving unit, like a diesel engine and especially a diesel engine flywheel
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with a driven unit like a transmission or generator. In such cases, the diesel engine flywheel is
connected to one half of the shaft coupling while the transmission or generator is connected to the
other coupling half.
BACKGROUND OF THE INVENTION
[0002] Elastic shaft couplings for connecting a drive unit with a driven unit are of course known. The
generally annular shaft coupling may be subdivided into segments and each of the segments can
include a plate segment forming part of one of the two coupling halves and the plate segments can
be connected together by an elastic material which may be bonded to the axial surfaces of the plate
segments by vulcanization thereto. The term "axial surfaces" is here used to refer to the surfaces of
the segments which face in the axial direction.
[0003] Segmented shaft couplings are available in a variety of configurations and these include the
shaft couplings of German Patent Document DE 36 16 232 A1 (see especially the ring arrangement 3
thereof) and the segmented coupling of German Patent Document DE 34 34 722 A1.
[0004] Segmentation of the coupling enables the coupling to be made from smaller components and
can be used whenever one piece coupling half plates or elastomeric members cannot be fabricated
in an economical manner or where one piece couplings cannot be mounted in an economical or
convenient manner. They are also of advantage wherever replacement of the components are
necessary and have been found to be useful wherever the machine parts connected by the shaft
coupling cannot be moved apart to enable replacement.
[0005] In the past it has been necessary to fabricate the metal segment plates from relatively
expensive cast steel in the same manner as flanges were formed. Furthermore, it has been required
or desirable to support the coupling at a bearing at a hub, usually via a lateral ring to stabilize the
segments during rotation of the coupling against the centrifugal forces which tend to develop in them.
Both of these approaches are expensive and hence prior shaft couplings of such types (see
especially DE 36 16 232 A1 for such stabilization) have not been considered cost effective in many
applications.
OBJECTS OF THE INVENTION
[0006] It is, therefore, the principal object of the present invention to provide an improved segmented
coupling of high torsional elasticity which is constructed more simply and hence is more cost
effective or economical than shaft couplings.
[0007] It is another object of the invention to provide an improved shaft coupling which is free from
drawbacks of earlier shaft coupling systems.
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[0008] Yet another object of the present invention is to provide a shaft coupling which has high
torsional elasticity, can be manufactured simply and economically and can be used highly effectively
between a drive and a driven unit, especially between a flywheel of a diesel engine and a
transmission or electrical generator.
SUMMARY OF THE INVENTION
[0009] A shaft coupling with high torsional elasticity is provided in accordance with the invention for
connecting a drive with a driven unit, the shaft coupling having a first generally annular coupling half
connectable to the drive and a second generally annular coupling half connectable to the driven unit,
each of the coupling halves comprising a plurality of coplanar plate segments having radial gaps
between them, the shaft coupling comprising elastomeric bodies between corresponding plate
segments and vulcanized to juxtaposed surfaces of the plate segments, the plate segments being
composed of metal sheet having at least main surfaces of the sheet which constitute the axial
surfaces thereof formed as nonmachined faces; and blocking elements at the radial gaps coupling
the plate segments of each half together across the respective gap and bracing the plate segments
against axial deformation.
[0010] According to the invention, the segment plates are thin metal sheet, for example steel sheet
which can have a thickness preferably ranging from 1 mm to say 25 mm. At least the major surfaces
of the sheet which form the axial surfaces of the segment plates are not machined, i.e. are not
subjected to chip-removal machining.
[0011] The segment plates are coupled together by at least one blocking element and the segment
plates according to the invention are braced against one another to counteract axial deformation.
[0012] An important advantage of the present invention is that the shaft coupling can be fabricated in
a highly economical manner since its metallic parts can be cut from thin steel metal, e.g. by
stamping or in another non-machining approach (e.g. laser beam cutting). The expression "thin sheet
metal" or "thin sheet" is intended to mean that the metal segment plates have thicknesses which are
up to 50% of the wall thickness of conventional cast steel flanges or cast steel segment plates. Since
the main surfaces of the segment sheets which constitute the axial surfaces of the segment plates
are not machined by a chip removal method the fabrication cost on the one hand is minimized and
on the other hand the segment plates are completely free from distortion which can result from
heating effects and from internal stresses which cannot be excluded in machining operations. The
coupling of the invention utilizing the thin segment plates is therefore not only economical but has
technological advantages and eliminates the need for operation subsequent to the stamping or
punching operation with which the segment plates are formed.
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[0013] As far as the blocking elements are concerned, they preferably are connected to individual
segment plates and connect the segment plates of each coupling half together by overlapping the
other segment plate of the respective coupling half.
[0014] More particularly, each of the blocking elements, located at the edge with respect to the
peripheral direction of a segment can extend across the respective coupling gap to overlap the
neighboring segment plate and preferably can have a notch, recess or groove into which the other
segment plate extends so that each blocking element connected to one segment plate straddles the
segment plate on the other side of the gap.
[0015] Because of the blocking elements which themselves are very simple and economical, the
previously used more complex and thus expensive systems for stabilizing the segment plates can be
eliminated.
[0016] Coupling flanges of steel sheet are themselves already known in annular elastic couplings. An
example can be found in the CENTAX(R) couplings of the present patent application owner which
have been supplied in large number for at least a decade. These elastic couplings are comprised
substantially of two concentrically arranged annular flanges with elastic rubber ring coupling
elements vulcanized between the flanges and bonded to them. The transfer of torque between the
parts of the coupling is effected by screws or like connectors whereby one flange at the outer
diameter and the other flange at the inner diameter can be bolted to the drive unit and the driven unit,
usually a flywheel and hub. The flanges in the form of one piece steel rings enable a simple and
economical fabrication and guarantee, in addition high precision and good balance for low weight
and low inertial torque transfer.
[0017] According to a further feature of the invention, the blocking elements which are located in the
region of the edge of a segment and extend across the gap to straddle the neighboring segment
plate and brace each other against axial deformation are engageable with one another in the
peripheral direction to transfer angular force from one to the other.
[0018] By contrast with the lateral ring of a coupling of the type described in German patent
document DE 36 16 232 A1, supported via a rotary bearing on the hub and which stabilizes the
segments against the centrifugal forces which arise, the invention provides blocking elements which
in the peripheral direction of the coupling enable the segment plates to interlock but also prevent
axial deformation so that the plat s cannot bend or buckle, relative to one another. Such blocking
elements can have very simple constructions as will be developed below.
[0019] According to a further feature of the invention, the segment plates and the elastomeric or
rubber coupling bodies are vulcanized together.
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[0020] In conventional segmented couplings the individual segments, formed by two segment plates
and the elastomeric bodies between them, are vulcanized together. The vulcanizing tools can thus
be comparatively simple.
[0021] With the invention, however, the segments of a coupling were all formed under the same
fabrication conditions so that each elastomeric element has the same quality and the same elasticity
as each other element of the coupling and the coupling as a whole has significantly greater
homogeneity or a homogeneity which could not be achieved with earlier couplings with respect to
elastic and dynamic properties. In accordance with this aspect of the invention, all of the segmentshaped elastomeric bodies of the coupling are vulcanized in one common vulcanizing operation to
rings of metal which are later subdivided into segments or into segments subdivided from rings by
laser cutting.
[0022] Advantageously and in accordance with a feature of the invention, each blocking element has
at least two lugs forming a lug arrangement in which each lug is affixed to one segment plate and
partly engages over the neighboring segment plate in the peripheral direction. The blocking lugs
themselves can be simple plates or sheets and thus do not have to have any special requirements in
a structural sense. The blocking element that is comprised of two lugs may form one of a pair and
both can be affixed to one segment plate and can straddle both sides of the neighboring segment
plate in the axial direction.
[0023] However, in a preferred embodiment, the two blocking elements of a mating pair can each be
affixed to one of the two neighboring segment plates, can span the radial gap between them and, on
the opposite segment plate can straddle the opposite axial faces. The two blocking elements may
engage one another in the peripheral direction for torque transfer purposes as soon as there has
been a certain amount of yielding of the elastic elements.
[0024] The lugs of the blocking elements can be affixed to the same axial side of the respective
segment plates or on opposite axial sides thereof and in accordance with a further feature of the
invention, the blocking elements may be two plates affixed to one segment and straddling the other.
Any means of attachment of the blocking elements may be used and preferably such means can
include welding, riveting, bolting, or the like. When removable bolts and nuts are used, additional
means can be provided, for example, pins with a clearance fit can be used to prevent rotation of the
blocking elements at the edge of the respective segment.
[0025] The lugs or plates forming the blocking element may be circular arc segments and can have
inner or outer peripheries which are flush with the corresponding peripheries of the respective
segment plates.
[0026] Whether the lug is placed close to the inner periphery or the outer periphery will depend on
the space available, whether the surfaces of the segment plates in the region are planar or bent
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inwardly or outwardly or in an axial direction, depending on the coupling design. As a result, the
blocking elements will be provided on the side of the coupling half concerned which is opposite the
force application in the radial direction.
[0027] It has been found experimentally that a coupling in accordance with the invention is highly
advantageous when it consists of only two segments. However, this should be considered only the
minimum number of segments which can be provided in accordance with the invention. In practice,
the number of segments which can be provided in accordance with the invention will depend on the
load and the dimensions of the coupling as a whole.
[0028] In the method aspects of the invention, the metallic parts forming the segment plates are
initially formed in respective closed rings. The elastomeric coupling body in segment shapes are
then provided between the annular plates vulcanized to the metal rings, whereupon the segments
are subdivided from one another in the gaps between the coupling body segments.
[0029] In this case the vulcanization is effected in the intermediate assembly as an annular body.
[0030] Alternatively, the metal parts of the segments, namely the plates, are initially provided as
closed rings, subdivided into individual segment plates and all of the segment plates or the
couplings are vulcanized together to the respective elastomeric segments. In both of these methods,
the closed rings initially can be formed from steel sheet and can be subdivided by means of laser
beam cuttings so that at least the mean surfaces of the sheets which form the axial faces of the
segment plates need not be machined, i.e. processed by a chip-removal operation.
[0031] The fabrication processes are likewise relatively inexpensive and can provided a highly
uniform reproducible product at a minimum cost.
BRIEF DESCRIPTION OF THE DRAWING
[0032] The above and other objects, features, and advantages will become more readily apparent
from the following description, reference being made to the accompanying drawing in which:
[0033] FIG. 1 is an axial end view of an elastic sheet coupling in accordance with the invention;
[0034] FIG. 2 is a cross sectional view taken along the line II-II of FIG. 1;
[0035] FIG. 3 is a radial section taken along the line III-III of FIG. 2;
[0036] FIG. 4 is an enlarged detail view of a first blocking element for preventing relative axial
movement of two mutually neighboring segments;
[0037] FIG. 5 is a cross sectional view taken along the line V-V of FIG. 4;
[0038] FIG. 6 is a view similar to FIG. 4 but illustrating another configuration of a blocking element
according to the invention; and
[0039] FIG. 7 is a cross sectional view taken along the line VII-VII of FIG. 6.
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SPECIFIC DESCRIPTION
[0040] As can be seen from FIG. 2, a shaft coupling in accordance with the invention can comprise a
first planar coupling flange 11 and a second axially dished coupling flange 12 which can comprise a
planar ring 12c, a frustoconical intermediate portion 12d and a planar hub portion 12e, between
which elastomeric coupling bodies 13 are vulcanized.
[0041] The flanges 11 and 12, which can be seen to be segmented in FIGS. 1 and 3, are originally
formed as annular sheet steel members and are shaped by stamping or punching and subsequently
subdivided by laser cutting so that neither of these flanges nor the segment plates from which they
are fabricated, need to be machined, especially on their surfaces facing in the axial direction, i.e.
their respective axial faces.
[0042] In the shaft coupling itself, the coupling flanges 11 and 12, therefore, are not present in their
original circular or annular ring shapes but rather in the form of ring segments 11a, 11b or 12a, 12b.
[0043] In the embodiment shown in FIGS. 1-3, the coupling consists of only two somewhat
semicircular segments, each of which consists of two segment plates 11a, 12a or 11b, 12b, and a
respective and generally semicircular segmental elastomeric body vulcanized between the two
segment plates. While the illustrated coupling, therefore, has only two such segments, it is also
possible to provide a larger number of segments for each coupling.
[0044] The coupling shown in FIGS. 1-3, therefore, comprises a total of four metallic flange elements
which have been designated as segment plates and the reference numeral 14 has been used to
refer to segment plates generally. Each of the segment plates 14 is comprised of any sheet metal of
a quality steel, for example, a stainless steel. The term "thin" when referring to the thin sheet metal
from which the segment plates 14 are constituted is intended to mean a thickness significantly less
than the thickness of the flanges used heretofore in segmented couplings and preferably no greater
than 50% of the thickness of such flanges. Furthermore, differing from conventional flanges in shaft
couplings, these sheet metal flange plates are not machined or subjected to a chip removal
processing along their axial surfaces. Any cutting is confined to the inner and outer peripheral edges
and the edges of the segment plates defining the radial gaps between the segments.
[0045] Since the segment plates are not annular and are relatively thin, the invention provides that
blocking elements 15 or 16 are provided on opposite sides of the segment plates to brace the
segment plates relative to one another in the axial direction.
[0046] As can be seen from FIGS. 1-3, moreover, the blocking elements 15 which may be provided
between neighboring segment plates will generally take up more space than the blocking elements
16. The blocking elements 16, moreover, enable the coupling to be flatter in the axial direction and
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require a reduced degree of dishing of the segment plates 14 forming the flange 12. The flange
element 11 can be completely planar as has been noted to allow it to be bolted or otherwise affixed
directly to the flywheel of an engine.
[0047] Details of the blocking elements 15 and 16 can be seen in FIGS. 4 and 5 and FIGS. 6 and 7,
respectively.
[0048] The blocking elements 15 shown in FIGS. 4 and 5 are formed from two mirror-symmetrical and
otherwise identical flat lugs or plates 17, especially steel plates. The two lugs 17 forming one
blocking element 15 are coextensive and are connected by two bolts 18. The bolts 18 have heads
18a (FIG. 5) which can form hexagonal sockets for a hexagonal key and threaded shafts 18b to
which locking nuts 18c are affixed.
[0049] The lugs 17 have extensions beyond their bolted portions which cross the radial gap between
neighboring segment plates 14 and straddle the segment plate 14 to which the lugs are not bolted,
thereby bracing the two plates 14 against axial forces. The radial gap 19 is defined between rounded
edges 14a and 14b of the two neighboring flange plates 14. Thus the lugs project beyond the edge
14b of the flange plate 14 to which they are attached and overlap the axial faces of the flange plate
14 whose plate 14a defines the other side of the radial gap 19.
[0050] The lugs 14 are practically circular arc segments and have peripheral edges 21 which
conform and are flush with the inner peripheral edge of the segment plates 14. Of course, the lugs 17
can be provided along the outer periphery if desired, in which case the outer edges of the plates will
conform to the peripheral edge of the segment plates 14.
[0051] Since the coupling of this embodiment consists of two segments, two blocking elements 15
are provided across each of the radial gaps 19.
[0052] On the other side of the coupling, the segment plates 19 are also braced against one another
with corresponding blocking elements or the blocking elements 16 which are of flatter configuration
and which have been shown in greater detail in FIGS. 6 and 7.
[0053] The blocking device 16 also comprises two lugs 22. The lugs 22 however differ from those of
the blocking element 15 in that they are not both attached to the same segment plate 14 but rather
one is disposed on one of the segment plates while the other is affixed to the other segment plate 14.
Preferably, however, both are provided on the same axial side.
[0054] One part of each of the lugs 22 is affixed to the respective segment plate 14 by screws 23
and is held from pivoting by a pin 22 which has a clearance fit in a lined hole of the lug 22 and the
respective segment plate 14. The lugs have projecting portions 22 which reach across the radial gap
19 and overlie the other segment plate 14. Thus each projecting portion 22a extends across the gap
19 defined by the two radial edges 14a, 14b. This contrasts with the straddling arrangement of the
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projecting portion 17a of the lug 17 of FIGS. 4 and 5. The screws 23 are countersunk screws in this
embodiment to maintain the flat configuration.
[0055] As is also visible from FIGS. 6 and 7, the edge zones of the elastomeric bodies 13 are set
back by a short distance from the edges of respective segment plates 14 and in this setback region
the blocking element or device 16 is provided.
[0056] As noted, the lugs 22 can be provided along the outer or inner peripheries of the segment
plate and in the embodiment shown in FIGS. 6 and 7 are disposed along the inner periphery flush
with the edge 20. As also can be seen from FIGS. 6 and 7, the projecting portions 22a can be so
interfitted (FIG. 6) that the segment plates 14 not only brace each other against axial deformation but
the lugs 22 can engage one another in the peripheral direction to transfer torque once the gap 19
has narrowed sufficiently.
[0057] 7] As has been described, the metal elements of each coupling half are initially a single ring
and can be vulcanized as a ring to the elastomeric body 13 before the rings are cut through to form
the gaps 19 and separate the segment plates by the laser-cutting operation. lsqb;0057]
[0058] Alternatively, the ring is cut through and the elastomeric body is then vulcanized to the
segment. In either case the vulcanization can be effected simultaneously for all segments to ensure
an optimal uniformity of the elastomeric element and their bonds to the segment plates.
[0059] The lugs 22 need not be provided on the same axial side of the segment plates 14 as shown
in FIG. 7 but can be located on opposite sides thereof. The embodiment as shown in FIGS. 6 and 7
provide however the flattest configuration of the coupling. Furthermore, the blocking elements on the
two sides of the coupling need not be of different types. For example the blocking elements of type
15 may be provided on both coupling halves or, conversely, the coupling element of type 16 may be
used on both coupling halves.
[0060] In either case the coupling elements occupy space which is provided at the segment plates in
the setback region of the elastomeric body so that they do not contribute to an increased overall axial
thickness of the coupling.Claims:
I claim:
1. A shaft coupling with high torsional elasticity for connecting a drive with a driven unit, said shaft
coupling having a first generally annular coupling half connected to said drive and a second
generally annular coupling half connected to said driven unit, each of said coupling halves
comprising a plurality of coplanar plate segments having radial gaps between them, said shaft
coupling comprising elastomeric bodies between corresponding plate segments and vulcanized to
juxtaposed surfaces of said plate segments, the plate segments being composed of metal sheet
having at least main surfaces of the sheet which constitute the axial surfaces thereof formed as
71/425
nonmachined faces; and blocking elements at said radial gaps coupling the plate segments of each
half together across the respective gap and bracing the plate segments against axial deformation.
2. The shaft coupling defined in claim 1 wherein each of said blocking elements is connected to one
of said plate segments, is disposed at an edge of the respective plate segment, extends across the
respective gap and engages over a neighboring plate segment.
3. The shaft coupling defined in claim 1 wherein said blocking elements are disposed at respective
edges of the plate segments, extend across the respective gaps and engage a neighboring plate
segment whereby the blocking elements mutually brace the plate segments against axial
deformation.
4. The shaft coupling defined in claim 1 wherein said plate segments are composed of steel sheet.
5. The shaft coupling defined in claim 1 wherein all of said elastomeric bodies are vulcanized
between the respective plate segments together.
6. The shaft coupling defined in claim 1 wherein at least one of said blocking elements comprises a
pair of lugs, each of said lugs being affixed to one of said plate segments and reaches over a
neighboring plate segment in a peripheral direction.
7. The shaft coupling defined in claim 6 wherein at least one of said blocking elements comprises
two lugs which are affixed on opposite sides of one of said plate segments and has projecting
portions straddling the neighboring plate segment.
8. The shaft coupling defined in claim 6 wherein said lugs are affixed on the same side of a plate
segment and a neighboring plate segment to reach across a radial gap between said plate
segments and axially brace said segments against one another.
9. The shaft coupling defined in claim 6 wherein said lugs are lugs are provided on the same plate
segment.
10. The shaft coupling defined in claim 6 wherein said lugs are provided on plate segments on
opposite sides of a respective radial gap.
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11. The shaft coupling defined in claim 6 wherein said lugs are disposed so as to peripherally
engage one another.
12. The shaft coupling defined in claim 6 wherein at least one of said lugs is connected to a
respective plate segment by a fastener and is prevented from rotating by a pin transfixing said lug
and the respective plate segment.
13. The shaft coupling defined in claim 6 wherein said lugs are provided along a periphery of the
respective plate segments and are flush with said periphery.
14. The shaft coupling defined in claim 6 wherein said lugs conform to circular arc segments.
15. The shaft coupling defined in claim 6 wherein said lugs are coextensive with one another on
opposite sides of a plate segment and are connected together by fasteners passing through a
respective plate segment.
16. A method of making a shaft coupling comprising the steps of:
providing two metal rings having major surfaces adapted to form axial faces of the shaft coupling
without machining;
positioning elastomeric segmental bodies between said rings and vulcanizing said surfaces to said
body;
radially subdividing said rings between the bodies to form respective coupling segments; and
assembling said segments with blocking elements at radial gaps therebetween said blocking
elements bracing the plate segments formed by subdividing said rings against axial deformation.
17. The method defined in claim 16 wherein the rings are cut by laser beam cutting.
18. A method of making a shaft coupling comprising the steps of:
providing two metal rings having major surfaces adapted to form axial faces of the shaft coupling
without machining;
subdividing said rings into individual segment plates;
for all of the segment plates of a coupling, vulcanizing between pairs of said segment plates to form
respective segments, respective elastomeric coupling bodies in common; and
assembling said segments with blocking elements at radial gaps therebetween said blocking
elements bracing the plate segments formed by subdividing said rings against axial deformation.
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19. The method defined in claim 18 wherein the cutting is effected by laser beam cutting.
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9. DE10240446 - 05.08.2004
SENSOR MODULE
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=DE10240446
Inventor(s):
KANDLER MICHAEL [DE] (--)
IP Class 4 Digits: H01F
IP Class:
H1F21/02
E Class: B60C23/04C
Application Number:
US20030653653 (20030902)
Priority Number: DE20021040446 (20020902)
Family: DE10240446
Abstract:
THE INVENTION RELATES TO A SENSOR MODULE IN A FLEXIBLE HOUSING WITH INTEGRATED
TRANSMISSION MEANS. A POSSIBLE APPLICATION OF SUCH A FLEXIBLE SENSOR MODULE
WOULD BE THE USE AS TRANSPONDER-BASED TIRE PRESSURE MEASURING SYSTEM. HERE,
THE COMPLETE MODULE COULD BE VULCANIZED INTO THE TIRE, AND THE DATA COULD BE
TRANSMITTED BY MEANS OF A STANDARDIZED RECEIVER UNIT. THE TRANSMISSION MAY
HEREIN BE MADE BY RADIO OR INDUCTIVELY, FOR EXAMPLE.Description:
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a module made of one or more semiconductor sensors,
such as a temperature sensor, a tire pressure sensor, an acceleration sensor, a rotation speed
sensor, a steering angle sensor, etc., in a flexible housing as it can, among other things, be
vulcanized into rubber tires.
[0003] 2. Description of the Related Art
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[0004] In order to increase the operational safety of vehicles of all kinds, the development of
technical assemblies for monitoring most varied properties of the wheels and tires has been worked
on for a long time. In this context, properties to be monitored can be the temperature, the internal
pressure, the deformation, the acceleration, the tilt angle etc. of the wheels or tires. Changes on the
wheels and tires caused by the usage and wear are to be recognized to avoid accidents or at least
minimize the risk of accidents. Especially in the area of passenger transport, such as at aircraft tires,
bus tires, or railway wheels monitoring the tires and wheels could bring much more safety.
[0005] From Proc. IEEE 1998 MMT/AP International Workshop on Commercial Radio Sensor and
Communication Techniques, pages 83 to 96, the use of surface wave sensors for the detection of the
deformation of the tires is known. The cause of the deformation, however, such as temperature,
internal tire pressure, or outside influences, are not detected herewith. The detected signal may then
be transmitted to a vehicle mounted receiver unit in a wireless manner, for example inductively or by
radio.
[0006] Another solution for the detection of the tire deformation is described in EP 1 186 853 A2.
Here, the profile is impressed into the side wall of the rubber product, and the deformation of this
profile by influences, such as internal tire pressure or also outside influences, for example by the
road conditions, is measured in various ways. Possible principles for the detection of the profile
deformation are the capacitive measurement, the optical measurement, measurement by ultra-sound,
and also the measurement by eddy current.
[0007] Independent of the kind of the implementation of the sensor in the tire, the requirement
every system has to meet is the wireless transmission of the measurement data from the wheel or tire
to the vehicle. Suitable transmission methods hereof are the inductive transmission, the transmission
by means of electromagnetic waves in the infrared region, or also the transmission by radio.
[0008] Due to the high weight and rigidity of the housing, the sensors are in most cases currently
being mounted near the rim. The current supply, for example by means of batteries, or the
assemblies for the wireless data transmission, such as induction coils or antennas, currently also
have to be worked into the tire element separate from the sensor itself.
SUMMARY OF THE INVENTION
[0009] It is the object of the present invention to provide a sensor module in a flexible housing,
wherein the transmission means is integrated in the module. Furthermore, a method for the
production of such a sensor module is provided.
[0010] The present invention is a sensor module having at least one sensor element that is at least
partially surrounded by a housing, wherein the housing of the module is flexible, and a transmission
means for wireless data transmission is integrated in the module.
76/425
[0011] The present invention is a method for the production of a sensor module with at least one
sensor element, wherein the sensor elements are mounted on a flexible support material and are
contacted via a flexible cover.
[0012] In a sensor module of the aforementioned kind, this object is inventively achieved by
disposing one or more detector elements and at least one means for data transmission in a flexible
housing.
[0013] Depending on requirements of the application, due to the spatial conditions, it may be
required to adapt the flexible housing of the sensor module to the geometry. Accordingly, in an
advantageous embodiment of the invention, the shape of the housing is adapted to the geometry of
the tire or the tire profile.
[0014] In one embodiment of the invention, it is intended to strengthen the sensor module in the
area of the sensors, i.e. the semiconductor devices, to increase the mechanical stability of the
module.
[0015] In another embodiment of the invention, a memory element for storing specific data is
integrated in the flexible housing of the sensor module. A possible application of this memory
element in the sensor module could be the identification of tires. Data, such as date of purchase, tire
dealer, number of kilometers covered, vehicle owner, etc., may be stored on this memory element,
and thus be made available to garages or the user for technical inspection.
[0016] In an especially advantageous embodiment of the invention, the power for the operation of
the sensor module is inductively coupled in. This method has the advantage that no costly and
maintenance-intensive supply elements have to be accommodated on the module.
[0017] For the production of an inventive sensor module as well as advantageous embodiments, a
film serving as a stand-off with recesses for the semiconductor device(s) is glued onto a support foil
or film. Subsequently, the semiconductor devices are mounted in the so developed chip islands. By
means of known flip-chip technology the semiconductor devices are electronically contacted via a
metalized cover film. In this method, the transmission elements, such as antenna or coil, are also
integrated in the metalized cover foil, and are contacted via traces with the semiconductor devices.
[0018] In an embodiment of the inventive method, instead of the two-component support film with
stand-off, a support film with depressions for the semiconductor devices is used. The pressure
sensor chip(s) or, if necessary, further semiconductor devices may then be introduced into these
depressions, and again be contacted via a metalized and structured cover film.
[0019] In a further embodiment of the inventive production method, pressure sensors are
introduced into the module as semiconductor devices, and are provided with a drop of gel prior to
applying the metalized cover foil in order to enhance the pressure coupling to the pressure sensor(s).
77/425
BRIEF DESCRIPTION OF TEE DRAWINGS
[0020] These and other objects and features of the present invention will become clear from the
following description taken in conjunction with the accompanying drawing, in which:
[0021] FIG. 1 shows components of a sensor module with a flexible housing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] FIG. 1 shows an exemplary embodiment of a sensor module with a flexible housing. The
sensor module according to FIG. 1 consists of a support film 2, a stand-off 3, said stand-off 3 having
recesses that can accommodate the sensor element(s) 1, and a metalized cover film 5 with contact
element 7 and an integrated transmission element 6. Depending on the application of the sensor
module, one or more semiconductor devices and/or sensors may be integrated in the module.
Likewise, it is also possible to integrate signal processing integrated circuits apart from the sensors
in the module. Depending on the spatial condition, the operating voltage may be generated in the
module itself, e.g. by means of batteries, or inductively coupled in.
[0023] In an advantageous method for the production of the sensor module illustrated in FIG. 1,
the film 3 with its recesses for the accommodation of the sensor/semiconductor devices is applied
onto a support film 2. In these recesses, the sensor elements 1 are mounted. In order to establish the
mechanical and thermal contact, a fixing agent is required that adheres to both the semiconductor
body, e.g. silicon, and the support material, the film. For example, epoxy or silicon-based glues are
suitable, if necessary with an activator previously applied to the film. The so-far produced module is
then completed with a cover and contact film 5. Said cover and contact film 5 is coated with a
conductive and suitably structured layer, e.g. aluminum or copper, so that both the
sensor/semiconductor elements 1 may be contacted and the transmission means 6, e.g. the antenna,
is already realized by the conductive layer.
[0024] Instead of the film 3 utilized as stand-off, it is also possible to use a support film with
integrated depressions for the accommodation of the semiconductor devices.
[0025] A possible application of such a flexible semiconductor module would be the use as
transponder-based tire pressure measuring system. Here, the complete module could be vulcanized
into the tire, and the data could be transmitted by means of a standardized receiver unit. The
transmission may herein be made via radio or inductively, for example. Apart from sensor elements,
other semiconductor devices, such as signal processing integrated circuits, may also be integrated
in the sensor module. Such signal processing circuits then have the task to process the signals of
various sensors, for example temperature, pressure, or humidity sensors, or also calibration data of
the sensors, in order to have to transmit only one signal incorporating all the information to the
receiver unit. Likewise, it is possible to integrate, apart from the sensor elements, memory elements
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in the sensor module. In such storage modules, information, such as identification numbers, age
features, mileage readings, date of purchase, dealer, etc., could then be held.
[0026] Reference Numeral List
[0027] 1 sensor elements
[0028] 2 support material
[0029] 3 stand-off
[0030] 4 recess for the sensor elements
[0031] 5 metalized cover
[0032] 6 transmission means
[0033] 7 electrical contact for the sensor/semiconductor devicesClaims:
1. A sensor module comprising at least one sensor element that is at least partially surrounded by a
housing, wherein the housing of the module is flexible, and a transmission means for wireless data
transmission is integrated in the module.
2. The sensor module of claim 1, wherein the transmission means contains an antenna and/or an
induction coil.
3. The sensor module of claim 1, wherein an operational voltage for the sensor module is inductively
coupled in.
4. The sensor module of claim 1, wherein the operational voltage for the sensor module is
electromagnetically: coupled in.
5. The sensor module of claim 1, wherein the housing consists of one or more flexible foils.
6. The sensor module of claim 1, wherein the flexible housing is designed so that it may be
vulcanized into a rubber tire.
7. The sensor module of claim 1, wherein the flexible housing is adapted to the geometry of the
receiving unit.
8. The sensor module of claim 1, wherein the sensor module incorporates a memory element.
9. The sensor module of claim 1, wherein the sensor element is a pressure sensor and the entire
sensor module is inductively operated.
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10. The sensor module of claim 9, wherein a gel is introduced between the flexible cover and the
pressure sensor.
11. A method for the production of a sensor module with at least one sensor element, wherein the
sensor elements are mounted on a flexible support material and are contacted via a flexible cover.
12. The method of claim 11, wherein a flexible stand-off is introduced between the support material
and the cover.
80/425
10. DE10253262 - 27.05.2004
COMBINED RUBBER AND METAL WHEEL BEARING, COMPRISING CENTRAL ELEMENT
EXCEEDING AT FRONT AND PROVIDED WITH VULCANIZED RUBBER LAYER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=DE10253262
Inventor(s):
HINZE THILO [DE] (--)
Applicant(s):
VOLKSWAGENWERK AG [DE] (--)
IP Class 4 Digits: F16F; B60G
IP Class:
F16F1/38; B60G7/02
E Class: F16F1/38N
Application Number:
DE20021053262 (20021115)
Priority Number: DE20021053262 (20021115)
Family: DE10253262
Abstract:
THE BEARING (11) IS ASSEMBLED OF A RIGID OUTER ELEMENT (14) AND A RIGID INNER
ELEMENT (12) ACCOMMODATING A SOFT RUBBER ELEMENT (13) BETWEEN THEM AND AN
ADDITIONAL RIGID ELEMENT (15) EMBEDDED IN THE RUBBER. THE INNER ELEMENT (12) IS
DESIGNED AS A ROUND BAR WITH A CONICAL FRONT AREA (17) FOR BEING JOINED TO AN
ADJACENT COMPONENT (19). THE RUBBER ELEMENT (13) IS IDEALLY JOINED TO THE BAR (12)
BY VULCANIZATION.Description:
[0001] Die Erfindung bezieht sich auf ein Gummi-Metall-Lager fьr eine Radaufhдngung,
umfassend ein starres Aussenteil, ein starres Innenteil und ein weiches Gummielement, das
zwischen dem Aussenteil und dem Innenteil angeordnet ist.
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[0002] Derartige Gummi-Metall-Lager sind aus dem Stand der Technik allgemein bekannt und
werden beispielsweise in Radaufhдngungen von Personenkraftwagen aber auch anderen
Fahrzeugtypen eingesetzt.
[0003] Ein herkцmmliches Gummi-Metall-Lager ist in Fig. 2 beispielhaft dargestellt. Dieses Lager 1
besteht aus einem hьlsenfцrmigen Innenteil 2, einem Gummielement 3 sowie einem hьlsenfцrmigen
Aussenteil 4. Um bei einer hohen Radialsteifigkeit eine geringe Torsionssteifigkeit (Verdrehsteifigkeit)
zu gewдhrleisten, ist in dem Gummielement 3 eine starre Zwischenhьlse 5 angeordnet, die das
Gummielement 3 in ein дusseres Hьlsenelement und ein inneres Hьlsenelement unterteilt.
[0004] Die hohe Radialsteifigkeit ermцglicht ein direktes Anlenken des Fahrzeugs bei Kurvenfahrt.
Dies ist fьr die Fahrdynamik gьnstig. Eine geringe Torsionssteifigkeit gewдhrleistet zudem einen
guten Federungskomfort, weil dadurch der Anteil der nichtlinearen dynamischen Kennlinie des
Gummielements an der Gesamtfederrate gering bleibt.
[0005] Ьblicherweise wird das in Fig. 2 dargestellte, bekannte Lager 1 in einen Lenker 6 der
Radaufhдngung eingepresst und anschliessend mit Hilfe einer Schraube 7, die durch das
hьlsenfцrmige Innenteil gesteckt wird, sowie einer Mutter 8 an einem angrenzenden Bauteil 9
befestigt.
[0006] Die herkцmmliche Konstruktion ist in der Art und Weise ihrer Befestigung nachteilig. So
erfordert die reibschlьssige Schraubenverbindung zwischen dem Gummilager und beispielsweise
einem Radtrдger der Radaufhдngung aufgrund hoher Querkrдfte sehr hohe Vorspannkrдfte.
Hieraus resultiert wiederum die Notwendigkeit eines grossen Schraubendurchmessers, womit
zwangslдufig auch der Durchmesser des Lagers stark anwдchst.
Aufgabenstellung
[0007] Der Erfindung liegt die Aufgabe zugrunde, hier Abhilfe zu schaffen.
[0008] Zur Lцsung dieser Aufgabe wird ein Lager mit den Merkmalen des Oberbegriffs von
Anspruch 1 vorgeschlagen, bei dem das Innenteil als Zapfen ausgebildet ist. An dem Zapfen ist das
Gummielement befestigt, vorzugsweise anvulkanisiert. Zudem weist der Zapfen einen aus dem
Gummielement hinausragenden konischen Befestigungsabschnitt zur Anbindung an ein
benachbartes Bauteil auf.
[0009] Durch die Verwendung eines Zapfens mit konischem Befestigungsabschnitt als Lagerkern
anstelle einer zylindrischen Innenhьlse mit Durchgangsloch fьr die Anbindung eines benachbarten
Bauteils, beispielsweise eines Radtrдgers einer Radaufhдngung, lдsst sich die Lagerbefestigung
optimieren.
82/425
[0010] Der Konussitz ermцglicht eine sehr gute, formschlьssige Kraftьbertragung quer zur
Lagerachse, die geringere Vorspannkrдfte als eine Schraube erfordert. Dies ermцglicht wiederum
einen geringeren Materialeinsatz und eine kompaktere Bauform des Lagers.
[0011] Bei gleichbleibender Radialsteifigkeit kann darьber hinaus wegen des geringeren
Durchmessers die Torsionssteifigkeit vermindert werden, wodurch sich zusдtzlich der Fahrkomfort
verbessern lдsst.
[0012] Weiterhin besitzt die erfindungsgemдsse Lцsung gegenьber der Schraubenvariante ein
geringeres Gewicht.
[0013] Aufgrund der geringeren benцtigten Vorspannkrдfte wird ьberdies eine Erleichterung bei
der Montage erzielt.
[0014] Weitere, vorteilhafte Ausgestaltungen der Erfindung sind in den Patentansprьchen
angegeben.
Aufьhrungsbeispiel
[0015] Nachfolgend wird die Erfindung anhand eines in der Zeichnung dargestellten
Ausfьhrungsbeispiels nдher erlдutert. Die Zeichnung zeigt in:
[0016] Fig. 1 ein Gummi-Metall-Lager gemдss einem Ausfьhrungsbeispiel der Erfindung, und in
[0017] Fig. 2 ein Gummi-Metall-Lager herkцmmlicher Bauart.
[0018] Das Ausfьhrungsbeispiel zeigt ein Gummi-Metall-Lager 11 fьr eine Radaufhдngung eines
Kraftfahrzeugs, das beispielsweise zwischen einem Querlenker und einem Radtrдger, jedoch auch
an anderer Stelle eingebaut werden kann.
[0019] Das erfindungsgemдsse Gummi-Metall-Lager 11 umfasst ein starres, metallisches Innenteil
12 in Form eines massiven Zapfens, an dem ein Gummielement 13 befestigt, vorzugsweise
anvulkanisiert ist.
[0020] Das Gummielement 13 ist wiederum von einem starren Aussenteil 14 umgeben, das bei der
hier beispielhaft dargestellten Einbausituation in den Querlenker 16 eingepresst ist. Vorzugsweise ist
das Aussenteil 14 als metallische Hьlse ausgebildet, in der das Gummielement 13 befestigt ist. Dies
kann beispielsweise durch Anvulkanisieren erfolgen.
[0021] In das Gummielement 13 ist ein starres Zwischenteil 15 konzentrisch eingebettet, das das
Gummielement 13 in ein дusseres und ein inneres Hьlsenelement unterteilt. Durch die beiden
Gummischichten zwischen dem Aussenteil 14 und dem Zwischenteil 15 einerseits und dem Innenteil
12 und dem Zwischenteil 15 andererseits ergibt sich eine hohe Radialsteifigkeit, die ein direktes
Anlenken des Fahrzeugs bei Kurvenfahrt ermцglicht. Zudem bleibt die Torsionssteifigkeit gering und
damit fьr den Fahrkomfort gьnstig. Dabei ist die vorzugsweise aus Metall gefertigte Zwischenhьlse
83/425
15 in bezug auf das Aussenteil 14 und das Innenteil 12 berьhrungsfrei, beispielsweise konzentrisch,
angeordnet.
[0022] Das Innenteil 12, das wie bereits ausgefьhrt, als massiver Zapfen ausgebildet ist, weist
einen konischen Befestigungsabschnitt 17 auf, der aus dem eigentlichen Lager 11 bzw. aus dem
Gummielement 13 hinausragt. An diesem Befestigungsabschnitt 17 wird ein benachbartes Bauteil,
hier beispielhaft der Radtrдger 19 befestigt, der seinerseits eine Цffnung mit einer konischen
Anlageflдche 20 aufweist.
[0023] Bei der Montage wird der Zapfen des Lagers 11 durch die Цffnung des Radtrдgers 19
hindurchgefьhrt, bis sich der konische Befestigungsabschnitt 17 des Innenteils 12 an der konischen
Anlageflдche 20 formschlьssig abstьtzt. Hierbei erfolgt gleichzeitig eine Zentrierung zwischen dem
Lager 11 bzw. Innenteil 12 und dem benachbarten Teil bzw. Radtrдger 19 in bezug auf die
Lagerachse A.
[0024] Zur Verspannung der konischen Flдchen dient eine Befestigungsmutter 18, die
abschliessend auf einen Gewindeabschnitt 21 aufgeschraubt wird, der an das verjьngte Ende des
konischen Befestigungsabschnitts 17 anschliesst. Durch Anziehen der Mutter 18 wird der Radtrдger
19 gegen das Innenteil 12 des Lagers 11 verspannt. Zu diesem Zweck kann das
gegenьberliegende Ende 22 des Zapfens bzw. Innenteils 12 einen Werkzeugansatz aufweisen, ьber
den beim Spannen ein Gegenmoment aufbringbar ist.
[0025] Der Konussitz sorgt fьr eine sehr gute, formschlьssige Kraftьbertragung senkrecht zur
Lagerachse A.
[0026] Das Drehmoment an der Befestigungsmutter 18 fдllt gegenьber der Schraubenvariante
deutlich niedriger aus, da der Konus den Festsitz verstдrkt.
[0027] Aufgrund der geringeren benцtigten Vorspannkraft und dem Entfall der Schraube lдsst
sich das erfindungsgemдsse Lager 11 mit kleinerem Durchmesser ausbilden, als das in Fig. 2
dargestellte, herkцmmliche Lager 1.
[0028] Insbesondere ergeben sich ein kleinerer Aussendurchmesser des Innenteils 12 und des
Aussenteils 14, so dass das Lager 11 mit Zapfen in bezug auf seine Axiallдnge schlanker wird. In
den Fig. 1 und Fig. 2 ist dies durch das Verhдltnis des Durchmessers D des Aussenteils 14 zu
dessen Axiallдnge L ausgedrьckt. Dieses betrдgt bei dem herkцmmlichen Lager 1 in Fig. 2 etwa
1,40, bei dem Lager 11 nach dem Ausfьhrungsbeispiel in Fig. 1 hingegen lediglich etwa 1,23.
[0029] Ьberdies ergibt sich eine Gewichtsersparnis von etwa 17 %. Eine weitere Verminderung
des Gewichts kann durch eine hohle Ausbildung des Zapfens erzielt werden.
[0030] Eine weitere Verminderung von Lagerdurchmesser und Gewicht kann dadurch erzielt
werden, dass das Gewinde 21 und damit das Innenteil 12 im Durchmesser kleiner gewдhlt wird, da
die Vorspannkraft im Vergleich zur herkцmmlichen Variante kleiner ist.
84/425
Bezugszeichenliste
1 Gummi-Metall-Lager
2 Innenteil
3 Gummielement
4 Aussenteil
5 Zwischenteil
6 Querlenker
7 Schraube
8 Mutter
9 benachbartes Bauteil/Radtrдger
11 Gummi-Metall-Lager
12 Innenteil/Zapfen
13 Gummielement
14 Aussenteil
15 Zwischenteil
16 Querlenker
17 konischer Befestigungsabschnitt
18 Befestigungsmutter
19 benachbartes Bauteil/Radtrдger
20 konische Anlageflдche
21 Gewindeabschnitt
22 gegenьberliegendes Ende
A Lagerachse
D Durchmesser des Aussenteils 4 bzw. 14
L Axiallдnge des Aussenteils 4 bzw. 14Claims:
1. Gummi-Metall-Lager fьr eine Radaufhдngung, umfassend:
ein starres Aussenteil (14),
ein starres Innenteil (12), und
ein weiches Gummielement (13), das zwischen dem Aussenteil (14) und dem Innenteil (12)
angeordnet ist,
dadurch gekennzeichnet, dass das Innenteil (12) als Zapfen ausgebildet ist, an dem das
Gummielement (13) befestigt, vorzugsweise anvulkanisiert ist und der einen aus dem Gummielement
85/425
(13) hinausragenden, konischen Befestigungsabschnitt (17) zur Anbindung an ein benachbartes
Bauteil (19) aufweist.
2. Gummi-Metall-Lager nach Anspruch 1, dadurch gekennzeichnet, dass das Aussenteil (14) als
metallische Hьlse ausgebildet ist, in der das Gummielement (13) festgelegt, vorzugsweise
anvulkanisiert ist.
3. Gummi-Metall-Lager nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass in das
Gummielement (13) ein starres Zwischenteil (15) eingebettet ist.
4. Gummi-Metall-Lager nach Anspruch 3, dadurch gekennzeichnet, dass das Zwischenteil (15) als in
das Gummielement (13) eingebettete Hьlse ausgebildet und in bezug auf das Aussenteil (14) und
das Innenteil (12) berьhrungsfrei angeordnet ist.
5. Gummi-Metall-Lager nach einem der Ansprьche 1 bis 4, dadurch gekennzeichnet, dass das
Innenteil (12) bzw. der Zapfen an dem verjьngen Ende des konischen Befestigungsabschnitts (17)
einen Gewindeabschnitt (21) aufweist.
6. Gummi-Metall-Lager nach einem der Ansprьche 1 bis 5, dadurch gekennzeichnet, dass der
Zapfen massiv ausgebildet ist.
7. Gummi-Metall-Lager nach einem der Ansprьche 1 bis 5, dadurch gekennzeichnet, dass der
Zapfen hohl ausgebildet ist.
8. Gummi-Metall-Lager nach einem der Ansprьche 1 bis 7, dadurch gekennzeichnet, dass der
Befestigungsabschnitt eine andere, nicht-konische Form aufweist, die eine formschlьssige
Verbindung mit dem angrenzenden Bauteil gewдhrleistet.
Es folgt ein Blatt Zeichnungen
86/425
11. DE10354179 - 09.06.2004
MIXTURE FOR THE PRODUCTION OF AN OSCILLATING-DAMPING NORMAL CONCRETE, LIGHT
CONCRETE OR MORTAR COMPRISES VULCANIZED GROUND RUBBER MIXED WITH A BASE
MIXTURE OF CEMENT, ADDITIVES AND WATER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=DE10354179
Inventor(s):
VOLLENSCHAAR DIETER [DE] (--); THIELE KLAUS-DIETER [DE] (--)
Applicant(s):
VOLLENSCHAAR DIETER [DE] (--); THIELE KLAUS-DIETER [DE] (--)
IP Class 4 Digits: C04B
IP Class:
C4B16/04; C4B18/20; C4B20/00
E Class: C04B18/22; C04B28/02
Application Number:
DE20031054179 (20031119)
Priority Number: DE20021054353 (20021121); DE20031054179 (20031119)
Family: DE10354179
Abstract:
MIXTURE COMPRISES VULCANIZED GROUND RUBBER HAVING A GRAIN SIZE OF LESS THAN
0.8 MM AND A SPECIFIC SURFACE AREA OF MORE THAN 0.2 M/G MIXED WITH A BASE MIXTURE
OF CEMENT, ADDITIVES AND WATER.Description:
[0001] Die Erfindung betrifft eine Mischung fьr die Herstellung eines schwingungsdдmpfenden
Normalbetons, Leichtbetons oder Mцrtels nach dem Oberbegriff des Anspruchs 1.
[0002] In der DD 227 429 wird ein Fussbodenmцrtel beschrieben, der durch fьllstofffreie
Kautschukkrьmel modifiziert wird. Der Mцrtel enthдlt neben Zement, Wasser und mineralischen
Zuschlдgen, 5 - 10 M. -% Pulverkautschuk, Die Kautschukkrьmel werden durch ein aufwendiges
87/425
Fдllungsverfahren aus einem Kautschuklatex ausgefдllt. Da dieser Kautschuk unvernetzt und ohne
Fьllstoff ist, ist seine mechanische Belastbarkeit gering.
[0003] In der DE 20 012 088 wird eine Betonmischung beschrieben, die durch die Zugabe von
Gummigranulat modifiziert worden ist. Durch den Einbau von Gummigranulat mit Teilchengrцssen
von 1 mm bis 4 mm kann keine durchgehende Zementsteinschicht entstehen, so dass
Betonwerkstьcke mit nur geringen Druckfestigkeiten hergestellt werden kцnnen.
[0004] In der DE 19 941 527 wird eine Baustoffmischung aus zwei Komponenten beschrieben. Die
eine Komponente besteht aus Pulverkautschuk und einem anorganischen Fьllstoff. Die andere
Komponente besteht aus einer Dispersion eines Kunststoffes. In einer der beiden Komponenten wird
das Anmachwasser zugemischt. Die entstehende Mischung wird als Beschichtungsmaterial
verwendet. Das Beschichtungsmaterial hat elastischen Charakter durch die Kautschukpartikel. Da
aber auch dieser Kautschuk nicht vernetzt ist und nur zur Erhцhung seiner Standfestigkeit
anorganischen Fьllstoff enthдlt, kцnnen nur geringe Druckfestigkeiten erreicht werden.
[0005] Der Erfindung liegt die Aufgabe zugrunde, eine Mischung fьr die Herstellung eines
schwingungsdдmpfenden Normalbetons, Leichtbetons oder Mцrtels durch Zugabe von
ausvulkanisiertem Gummimehl zu einer Grundmischung aus Zement, Zuschlдgen und Wasser
anzugeben, die neben elastischen Eigenschaften auch eine hohe Druckfestigkeit besitzt.
[0006] Diese Aufgabe wird bei einer Mischung fьr die Herstellung eines schwingungsdдmpfenden
Normalbetons, Leichtbetons oder Mцrtels nach dem Oberbegriff des Anspruchs 1 durch die
Merkmale dieses Anspruchs gelцst.
[0007] Weiterbildungen und vorteilhafte Ausgestaltungen ergeben sich aus den Unteransprьchen.
[0008] Gegenьber der bekannten Mischung mit Gummigranulat einer Korngrцsse von 1 mm bis 4
mm und einer mittleren Oberflдche von 0,05 m/g bis 0,1 m/g weist das Gummimehl nach der
Erfindung eine geringere Korngrцsse und grцssere Oberflдche auf. Es hat sich gezeigt, dass ein
grosses Verhдltnis zwischen Oberflдche und Korngrцsse den Einbau der vernetzten
Kautschukpartikel des Gummimehls in die Zementsteinmatrix begьnstigt. Ein optimaler Einbau der
vernetzten Kautschukpartikel in die Zementsteinmatrix fьhrt zu einer Mischung fьr die Herstellung
eines schwingungsdдmpfenden Normalbetons, Leichtbetons oder Mцrtels, die nach Abbinden
einen reduzierten E-Modul bei erhцhter Druckfestigkeit aufweist.
[0009] Vorzugsweise besteht das Gummimehl aus geschredderten und anschliessend
gemahlenen Autoreifen, wobei die Korngrцsse ьber die Spaltgrцsse des Mahlwerks einstellbar ist.
[0010] Durch die Nutzung von Altreifen lдsst sich das Gummimehl kostengьnstig herstellen.
Zudem mindert sich das Entsorgungsproblem von Altreifen. Durch Mahlen geschredderter
Autoreifen wird das Ausgangsmaterial Schub- und Scherbeanspruchungen unterworfen. Diese
fьhren zu einer Erwдrmung und Bildung von Gasen sowie zu einer Zerteilung des
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Ausgangsmaterials. Nach dem Mahlvorgang kцnnen die noch warmen Partikel entspannen, wobei in
Hohlrдumen entstandene Gase deren Wдnde platzen lassen und plцtzlich entweichen. Dieser
Vorgang fьhrt zu einer Zerklьftung und damit Vergrцsserung der Oberflдche. Ьber die Spaltgrцsse
des Mahlwerks kann die Korngrцsse und in Verbindung mit weiteren Parametern mittelbar auch die
Oberflдche eingestellt werden.
[0011] Der Anteil an Gummimehl in der Mischung kann 0,5 - 30 M.-% bezogen auf die
Zementmenge betragen.
[0012] In diesem Bereich konnte eine besonders wirksame Beeinflussung des E-Moduls
nachgewiesen werden. In der Praxis ist ein Bereich zwischen 0,5 und 20 M.-% bevorzugt.
[0013] Das einzustellende Wasser/Zement-Verhдltnis betrдgt vorzugsweise < 0,4.
[0014] Da Zuschlagstoffe im vorliegenden Fall nicht in Form von Emulsionen bereitgestellt werden
mьssen, die das Wasser/Zement-Verhдltnis unkontrolliert beeinflussen kцnnen, ist hier eine genaue
Einstellung des Wasser/Zement-Verhдltnisses ьber die Dosierung von Zuschlagwasser mцglich.
Das fьr die Festigkeit mit verantwortliche Wasser/Zement-Verhдltnis kann dann im Interesse einer
hohen Druckfestigkeit eingestellt werden.
[0015] Weiterhin kann die Grundmischung einen hцheren Anteil an Zusatzstoffen, wie Microsilica,
Flugasche oder Trass und an Fliessmitteln umfassen, als eine Grundmischung fьr einen gummifreien
Normalbeton, Leichtbeton oder Mцrtel fьr etwa gleiche Festigkeitseigenschaften.
[0016] Durch den Einbau der inerten Gummipartikel in die Zementsteinmatrix wird die
Druckfestigkeit herabgesetzt. Dies wird durch einen hцheren Anteil an Zusatzstoffen fьr die
Grundmischung ausgeglichen. Die gummifreie Grundmischung hдtte dadurch eine hцhere
Druckfestigkeit. Da durch einen erhцhten Anteil an Feinstoffe umfassenden Zusatzstoffen die
Konsistenz der Mischung steifer wird, erfolgt ein Ausgleich durch erhцhte Fliessmittelzugabe, um
wieder eine ausreichen weiche Verarbeitungskonsistenz zu erhalten.
[0017] Nachfolgend wird die Erfindung anhand eines Ausfьhrungsbeispiels mit einer Zeichnung
nдher erlдutert. In der Zeichnung zeigen:
[0018] Fig. 1 eine Messanordnung mit einem Probekцrper und
[0019] Fig. 2 ein Messdiagramm mit Amplitudenangaben an Messorten von Probekцrpern.
[0020] Fьr eine gummifreie Grundmischung wurden folgende Komponenten und Anteile verwendet:
KomponenteTeile
Zement1,0
Zuschlag2,06
Wasser0,198
Verzцgerer0,006
Fliessmittel0,072
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Microsilica0,16
[0021] Der Anteil der vernetzten Kautschukpartikel in der Mischung kann 0,05 - 30 M.-% bezogen
auf den Zementanteil der Grundmischung betragen.
[0022] Beim Mischvorgang werden die Komponenten Zuschlag und Gummimehl und ggf.
Flugasche oder Trass mit ihren entsprechenden Massen vermischt und ebenso die Komponenten
Zement, Wasser, Fiiessmittel, Verzцgerer und ggf. Microsilica mit ihren entsprechenden Massen als
Zementleim ebenfalls vermischt. Danach werden die Gemische untereinander vermengt, indem zu
dem Trockengemisch aus Zuschlag und Gummimehl der Zementleim zugegeben wird, bis sich die
gewьnschte weiche Konsistenz eingestellt hat. Danach kann die Betonmischung aushдrten und
ergibt ein besonders gutes Verhдltnis zwischen Druckfestigkeit und E-Modul, deren Ausdruck sich in
einer sehr guten Duktilitдt widerspiegelt.
[0023] Nach diesem Verfahren wurden mehrere Mischungen mit unterschiedlichen Anteilen an
Gummimehl hergestellt und nach den entsprechenden DIN-Normen fьr die Druckfestigkeit und den
statischen E-Modul geprьft:
Mit Hilfe dieser Mischungsverhдltnisse und unter Variation der Menge an zugefьgtem Gummimehl
wurden die nachfolgenden mechanischen Kennwerte erhalten.
[0024] Das Eigenschaftsbild des aus dieser Betonmischung hergestellten Betons hat sich nicht nur
dahingehend verbessert, dass ein besonders gutes Verhдltnis von Druckfestigkeit und E-Modul
eingestellt werden konnte, sondern auch durch den Nachweis einer verbesserten Schalldдmmung
und Schwingungsdдmpfung. Ebenso konnten die Wasserundurchlдssigkeit, der Frostwiderstand,
der Tausalzwiderstand und die Wдrmedдmmung verbessert werden.
[0025] Dieser Beton kann bevorzugt im Schienenfahrzeugbereich, als Tunnelauskleidung, im
Hochbau und im Brьckenbau verwendet werden.
[0026] Zum Nachweis einer verbesserten Schalldдmmung und Schwingungsdдmpfung wurden
Probekцrper in Form von Balken hergestellt und auf einer Messanordnung vermessen.
[0027] Die entsprechende Messanordnung ist in Fig. 1 gezeigt. Sie besteht aus einem ortsfesten
Tisch 30 mit einer Spannvorrichtung 32, einem Oszillator 34 und einer Auswertevorrichtung mit
mehreren Messpunkten 1 bis 24.
[0028] Ein Probekцrper 36 ist einseitig auf dem ortsfesten Tisch 30 mit der Spannvorrichtung 32
eingespannt. Der freie Schenkel des Probekцrpers 36 wird etwa auf 1/3 seiner Lдnge vom freien
aus durch den Oszillator 34 zu Schwingungen angeregt, und zwar senkrecht zur Tischebene. An
Messpunkten 1 bis 4 werden die Auslenkungen des ortsfesten Tisches 30 und an Messpunkten 5 bis
24 Auslenkungen des Probekцrpers 36 erfasst.
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[0029] Die gemessenen Amplituden sind fьr jeden Messpunkt 1 bis 24 im Diagramm nach Fig. 2
dargestellt und die gemessenen Werte benachbarter Messpunkte untereinander verbunden. Die
Messungen wurden mit Probekцrpern nach den Betonmischungen 1 (gummifrei) und 5 (Gummimehl
20,5 M.-%) bei einer Frequenz von 60 Hz durchgefьhrt. Dabei ergeben sich fьr den Probekцrper
nach der Betonmischung 5 an allen Messpunkte deutlich niedrigere Amplituden als fьr den
Probekцrper nach der Betonmischung 1.
[0030] In weiteren Vergleichsmessungen konnten Dдmpfungen von 5 dB in einem
Frequenzbereich zwischen 120 Hz und 800 Hz nachgewiesen werden.Claims:
1. Mischung fьr die Herstellung eines schwingungsdдmpfenden Normalbetons, Leichtbetons oder
Mцrtels durch Zugabe von ausvulkanisiertem Gummimehl zu einer Grundmischung aus Zement,
Zuschlдgen und Wasser, dadurch gekennzeichnet, dass das Gummimehl eine Korngrцsse von 0,2
m/g besitzt.
2. Mischung nach Anspruch 1, dadurch gekennzeichnet, dass das Gummimehl aus geschredderten
und anschliessend gemahlenen Autoreifen besteht, wobei die Korngrцsse ьber die Spaltgrцsse
des Mahlwerks einstellbar ist.
3. Mischung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der Anteil an Gummimehl in
der Mischung 0,5 - 30 M.-% bezogen auf die Zementmenge betrдgt.
4. Mischung nach einem der Ansprьche 1 bis 3, dadurch gekennzeichnet, dass das einzustellende
Wasser/Zement-Verhдltnis < 0,4 betrдgt.
5. Mischung nach einem der Ansprьche 1 bis 4, dadurch gekennzeichnet, dass die Grundmischung
einen hцheren Anteil an Zusatzstoffen, wie Microsilica, Flugasche oder Trass und an Fliessmitteln
umfasst, als eine Grundmischung fьr einen gummifreien Normalbeton, Leichtbeton oder Mцrtel fьr
etwa gleiche Festigkeitseigenschaften.
Es folgt ein Blatt Zeichnungen
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12. EP1270661 - 02.01.2003
ARTICLE HAVING A COMPONENT OF A RUBBER COMPOSITION WHICH CONTAINS PARTICLES
OF PRE-VULCANIZED RUBBER AND HIGH PURITY TRITHIODIPROPONIC ACID
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=EP1270661
Inventor(s):
WIDEMAN LAWSON GIBSON (US); BALOGH GEORGE FRANK (US)
Applicant(s):
GOODYEAR TIRE and RUBBER (US)
IP Class 4 Digits: C08K; C08J; C08L; B60C
IP Class:
C8L21/00; C8J3/22; C8K5/372; B60C1/00
E Class: B60C1/00H; B60C1/00; C08J3/22L19+L21/00; C08J11/06+L21/00; C08K5/372+L21/00
Application Number:
EP20020013911 (20020624)
Priority Number: US20010896670 (20010629)
Family: EP1270661
Equivalent:
BR0203066; US2003032685; US6660791
Cited Document(s):
EP1031440; EP0488931; EP0780429
Abstract:
THE INVENTION RELATES TO ARTICLES OF MANUFACTURE, SUCH AS FOR EXAMPLE, TIRES
AND INDUSTRIAL PRODUCTS, WHICH HAVE AT LEAST ONE COMPONENT COMPRISED OF A
RUBBER COMPOSITION WHICH CONTAINS PARTICLES OF PRE-SULFUR VULCANIZED RUBBER
(E.G. GROUND RECYCLED RUBBER) AND HIGH PURITY TRITHIODIPROPIONIC ACID, WHEREIN
SAID TRITHIODIPROPIONIC ACID IS PREFERABLY PROVIDED AS PARTICLES OF A CARBON
BLACK COMPOSITE COMPRISED OF CARBON BLACK AND SAID HIGH PURITY
TRITHIODIPROPIONIC ACID. SAID HIGH PURITY TRITHIODIPROPIONIC ACID IS COMPRISED OF
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POLYTHIODIPROPIONIC ACIDS CONTAINING AT LEAST 80 WEIGHT PERCENT
TRITHIODIPROPIONIC ACID BASED UPON SAID POLYTHIODIPROPIONIC ACIDS.Description:
Field of the Invention
[0001] The invention relates to articles of manufacture, such as for example, tires and industrial
products, which have at least one component comprised of a rubber composition which contains
particles of pre-sulfur vulcanized rubber (e.g. ground recycled rubber) and high purity
trithiodipropionic acid, wherein said trithiodipropionic acid is preferably provided as particles of a
carbon black composite comprised of carbon black and said high purity trithiodipropionic acid. Said
high purity trithiodipropionic acid is comprised of polythiodipropionic acids containing at least 80
weight percent trithiodipropionic acid based upon said polythiodipropionic acids.
Background of the Invention
[0002] Various manufactured articles, including for example, various tires and industrial products,
have at least one component comprised of a sulfur vulcanized rubber. It is sometimes desired to
blend relatively small amounts of particles of pre-vulcanized rubber with a rubber composition for
one or more of such components followed by vulcanizing said rubber composition in a suitable mold.
Said pre-vulcanized rubber is in a form of ground, recycled pre-vulcanized rubber obtained from, for
example, various tires and industrial products. Scrap pneumatic tires may, for example, be used as a
source of such pre-vulcanized rubber.
[0003] In practice, scrap vulcanized rubber may be prepared for recycling, for example, by
depolymerizing it or otherwise changing its chemical character by various processes.
[0004] However, for the purposes of this invention, the scrap vulcanized rubber (the pre-vulcanized
rubber) may be reclaimed by grinding it down to extremely small particles and mixing it as a
compounding ingredient, usually as a filler, with other rubbers and rubber compounding ingredients
to form a rubber composition followed by sulfur vulcanizing the resultant rubber composition. In this
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case, the recycled pre-vulcanized rubber remains vulcanized but is in a form of a fine, particulate
pre-vulcanized rubber.
[0005] For the description of this invention, the terms "recycle" and "recycled rubber" are used
somewhat interchangeably and are intended to relate to sulfur pre-vulcanized rubber compositions
which have been ground into small particles unless otherwise designated.
[0006] Generally, such particulate recycled sulfur pre-vulcanized rubber is a complex mixture of
largely unknown diene-based elastomers and various rubber compounding ingredients, and may
contain a small quantity of textile fiber, and the like.
[0007] It has been observed that, after adding sulfur and accelerator to recycled sulfur prevulcanized rubber, followed by its revulcanization, the resulting physical properties, such as tensile
and elongation, are usually lower than the corresponding properties of the original vulcanized rubber
from which it was derived.
[0008] A process, for example, of improving properties of ground recycled sulfur vulcanized rubber
through use of a tris (2-aminoethyl) amine has been disclosed as U.S. Patent No. 6,077,874. U.S.
Patent No. 5,883,139 discloses the use of tetrathiodipropionic acid (which may be referred to herein
as S4) to improve properties of rubber compositions which contain particles of ground recycle, sulfur
cured diene-based rubber while the use of dithiodipropionic acid (S2) is not seen to improve the
properties of rubber compositions which contain particles of ground recycle, sulfur cured dienebased rubber. Therefore, it is considered herein that it would not be obvious to one having skill in
such art to successfully use a high purity trithiodipropionic acid (S3) to improve the properties of
rubber compositions which contain particles of ground recycle sulfur cured, diene-based rubber.
[0009] For the purposes of this invention, such high purity trithiodipropionic acid (S3) is a blend of
polythiodipropionic acids which contains at least 80, and preferably a range of from 80 to about 90,
weight percent 3,3'-trithiodipropionic acid weight of such acid, based upon said polythiodipropionic
acids, with the remainder comprised of other polythiodipropionic acids which are primarily said S4
and S2..
[0010] In the description of this invention, the term "phr" relates to parts by weight in a rubber
composition of an ingredient therein per 100 parts of elastomer. The terms "rubber" and "elastomer"
may be used interchangeably unless otherwise indicated. The terms "rubber composition" and
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"compound" may be use interchangeably unless otherwise indicated. The terms "vulcanize" and
"cure" may also be used interchangeably unless otherwise indicated.
Summary of the Invention
[0011] The present invention relates to a process for improving the properties of ground recycled
sulfur-vulcanized rubber and particularly improving sulfur curable diene-based rubber compositions
which contain particulate pre-sulfur vulcanized diene-based rubber.
Detailed Description of the Invention
[0012] In accordance with this invention, a process of preparing sulfur vulcanizable rubber
composition which comprises:
A. preparing a pre-blend by homogeneously blending
1. particles of a sulfur vulcanized, diene-based rubber composition, together with
2. high purity trithiodipropionic acid and particles of carbon black; or
3. particles of a carbon black composite comprised of carbon black and high purity
trithiodipropionic acid, having a weight ratio of said high purity trithiodipropionic acid to carbon black
in a range of from about 1/10 to about 10/1;
wherein said high purity trithiodipropionic acid having the general Formula (I): (I) HO2CCH2CH2 Sn - CH2CH2CO2H wherein n is a value of from 2 to about 5 and wherein at least 80 percent, and
preferably from about 80 to about 90 percent, of n is 3,
wherein about 0.18 to about 10, alternately from 1 to about 5, parts by weight of trithiodipropionic
acid is thereby provided per 100 parts by weight of diene-based rubber contained in said sulfur
vulcanizable rubber composition, and wherein said particles of sulfur vulcanized rubber composition
is of a particle size of less than 420 microns;
(B) mixing about one to about 40, alternately about 15 to about 20, parts by weight of said preblend with 100 parts by weight of at least one unvulcanized hydrocarbon diene-based, sulfur
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vulcanizable rubber to form a rubber composition comprised of said unvulcanized rubber and said
pre-blend.
[0013] Accordingly, in practice, the high purity trithiodipropionic acid may be added directly to the
particulate pre-vulcanized rubber or as said carbon black composite.
[0014] In further accordance with this invention, a rubber composition is provided which is
comprised of said pre-blend and said unvulcanized rubber.
[0015] In additional accordance with this invention, sulfur (referred to herein as free sulfur) is
blended with said rubber composition in an amount in a range of about 1 to about 5 parts by weight
thereof per 100 parts by weight of said unvulcanized diene-based rubber (usually together with
conventional sulfur cure accelerators and other conventional rubber compounding ingredients in
conventional amounts) to form a free sulfur-containing rubber composition.
[0016] In further accordance with this invention, said free sulfur-containing rubber composition is
sulfur vulcanized in a suitable mold under conditions of elevated temperature (e.g. in a range of
about 140 DEG C to about 180 DEG C) and pressure to form a sulfur vulcanized article of
manufacture.
[0017] In further accordance with this invention a sulfur vulcanized, pre-vulcanized rubbercontaining, rubber composition is provided.
[0018] In additional accordance with this invention, an article of manufacture is provided which
contains at least one component of a said sulfur vulcanized, pre-vulcanized rubber-containing,
rubber composition.
[0019] In further accordance with this invention, a tire is provided which contains at least one
component of a rubber composition comprised of said sulfur vulcanized, pre-vulcanized rubbercontaining, rubber composition.
[0020] In additional accordance with this invention, a tire is provided having a tread of a rubber
composition which is comprised of said sulfur vulcanized, pre-vulcanized rubber-containing, rubber
composition.
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[0021] It is considered herein to be significant that a high purity trithiodipropionic acid (S3) be used
for this invention in order to minimize the amount of dithiodipropionic acid (S2) which is considered
herein to be ineffective insofar as treating the pre-vulcanized rubber particles is concerning and
thereby in a nature as a diluent material in the trithiodipropionic acid (S3).
[0022] Such high purity trithiodipropionic acid may conveniently be prepared or obtained, for
example, by reacting sulfur dichloride (SCl2) of technical grade purity (ca at least 80 percent) to
react with 3-mercaptopropionic acid in toluene solution in a suitable container with coolant being
applied to the exterior of the container while the reaction proceeds.
[0023] In practice, the high purity trithiodipropionic acid, is in a form of a mixture of
polythiodipropionic acids which contains at least 80, preferably at least 85, and alternately in a range
of about 80 to about 90 weight percent of said trithiodipropionic acid, with a maximum of 20 weight
percent dithiopropionic acid and a maximum of 20, preferably a maximum of 10, weight percent
tetrathiopropionic acid in the polythiodipropionic acid mixture.
[0024] In practice, as hereinbefore related, said particulate, sulfur pre-vulcanized rubber
composition should have a maximum particle size of about 420 microns in diameter. It is considered
herein that particles greater than such size are of a size which is believed to be relatively impractical
for subsequent mixing with the treated vulcanized rubber/unvulcanized rubber because of an
expected rubber viscosity buildup in rubber processing equipment. In general, it is considered
herein that the sulfur pre-vulcanized rubber particles should more preferably have a maximum
particle size of about 250 microns (60 mesh) and even more preferably less than about 177 microns
(80 mesh). Preferably, such particles range from about 250 microns down to about 74 microns in
diameter.
[0025] The use of the high purity trithiodipropionic acid alone or particularly as a component of the
pre-formed carbon black composite is considered herein to be beneficial by providing the high purity
trithiodipropionic acid as being bound in a highly dispersed form on the carbon black and to thereby
enhance a relatively strong and efficient interaction with the particulate, sulfur-vulcanized rubber with
which it is blended.
[0026] Use of a composite blending procedure (forming a composite of carbon black and high
purity trithiodipropionic acid) with the recycle sulfur pre-vulcanized rubber is considered herein to be
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particularly advantageous as an alternative to use of a volatile organic solvent carrier for the high
purity trithiodipropionic acid for other various reasons, such as, for example, safety and
environmental considerations.
[0027] Representative of various particulate carbon blacks for preparation of said carbon black
composite are, for example, conventional rubber reinforcing carbon blacks with ASTM numbered
designations ranging from N110 to N991 which can be readily referenced, for example, in the 1990,
13th edition, of The Vanderbilt Rubber Handbook, Pages 417 and 418.
[0028] The composite of carbon black and high purity trithiodipropionic acid may be suitably
prepared, for example, by highly dispersing the high purity trithiodipropionic acid onto the surface of
the carbon black to thereby maximize the interaction of the trithiodipropionic with the surface of the
carbon black.
[0029] The dispersing of the high purity trithiodipropionic acid onto the carbon black surface may
be accomplished by, for example, by use of a volatile organic solvent which can readily be removed
by evaporation, or by spraying or atomizing the trithiodipropionic acid onto the surface of the carbon
black.
[0030] In the practice of this invention, the high purity trithiodipropionic acid alone or as a carbon
black composite is dispersed in the particulate sulfur pre-vulcanized rubber in a manner that the
trithiodipropionic acid itself is dispersed in the pre-vulcanized rubber in an amount ranging from 0.18
to 10.0 phr of the trithiodipropionic acid. Preferably, the level of trithiodipropionic acid that is
dispersed ranges from 0.36 to 5.0 phr, based upon the pre-vulcanized rubber.
[0031] For the purpose of the description of this invention, the particulate sulfur pre-vulcanized
rubber having been treated, or blended, with the composite of the dispersed trithiodipropionic acid
on carbon black may sometimes be referred to herein as "treated sulfur-vulcanized rubber" or
"treated recycled vulcanized rubber".
[0032] In the practice of this invention, the blend of particles of carbon black composite sulfur prevulcanized rubber may be mixed with unvulcanized rubber, particularly unvulcanized diene-based
elastomers. For such practice, as hereinbefore from about one to about 40 parts by weight of said
particulate blend may be mixed with 100 parts by weight of at least one unvulcanized rubber to form
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the resulting rubber composition. Preferably, from 2 to 30 parts by weight of said particulate blend is
mixed with 100 parts by weight of at least one unvulcanized rubber.
[0033] Representative examples of such unvulcanized rubber, or elastomer, are, for example,
diene-based elastomers as homopolymers and copolymers of conjugated diene hydrocarbons such
as, for example isoprene and 1,3-butadiene and copolymers of conjugated diene hydrocarbons with
an aromatic vinyl compound such as styrene and alphamethhyl styrene, preferably styrene.
[0034] Representative of such elastomers are, for example, cis 1,4-polyisoprene (natural and
synthetic), 1,4-cis-polybutadiene, butadiene/styrene copolymers, isoprene/butadiene copolymers,
styrene/isoprene/butadiene terpolymers, and mixtures thereof.
[0035] In one aspect at least two unvulcanized elastomers may be blended with said treated
recycled rubber. Such elastomers may be, for example, a combination of cis 1,4-polyisoprene rubber
(natural or synthetic, with natural rubber being preferred), 3,4-polyisoprene rubber,
styrene/isoprene/butadiene rubber, emulsion and solution polymerization derived styrene/butadiene
rubbers, cis 1,4-polybutadiene rubbers and emulsion polymerization prepared butadiene/acrylonitrile
copolymers.
[0036] In one aspect of this invention, an emulsion polymerization derived styrene/butadiene (ESBR) might be used having a relatively conventional styrene content of about 20 to about 28 percent
bound styrene or, for some applications, an E-SBR having a medium to relatively high bound styrene
content, namely, a bound styrene content of about 30 to about 45 percent.
[0037] The relatively high styrene content of about 30 to about 45 for the E-SBR can be considered
beneficial for a purpose of enhancing traction, or skid resistance, of the tire tread. The presence of
the E-SBR itself is considered beneficial for a purpose of enhancing processability of the uncured
elastomer composition mixture, especially in comparison to a utilization of a solution polymerization
prepared SBR (S-SBR).
[0038] By emulsion polymerization prepared E-SBR, it is meant that styrene and 1,3-butadiene are
copolymerized as an aqueous emulsion. Such are well known to those skilled in such art. The bound
styrene content can vary, for example, from about 5 to about 50 percent.
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[0039] The solution polymerization prepared SBR (S-SBR) typically has a bound styrene content in
a range of about 5 to about 50, preferably about 9 to about 36, percent. The S-SBR can be
conveniently prepared, for example, by organo lithium catalyzation in the presence of an organic
hydrocarbon solvent.
[0040] A purpose of using S-SBR is for improved tire rolling resistance as a result of lower
hysteresis when it is used in a tire tread composition.
[0041] The 3,4-polyisoprene rubber (3,4-PI) is considered beneficial for a purpose of enhancing
the tire's traction when it is used in a tire tread composition. The 3,4-PI and use thereof is more fully
described in U.S. Patent No. 5,087,668 which is incorporated herein by reference. The Tg refers to
the glass transition temperature which can conveniently be determined by a differential scanning
calorimeter at a heating rate of 10 DEG C per minute.
[0042] The cis 1,4-polybutadiene rubber (BR) is considered to be beneficial for a purpose of
enhancing the tire tread's wear, or treadwear. Such BR can be prepared, for example, by organic
solution polymerization of 1,3-butadiene. The BR may be conveniently characterized, for example, by
having at least a 90 percent cis 1,4-content.
[0043] The synthetic cis 1,4-polyisoprene and the natural cis 1,4-polyisoprene rubber are well
known to those having skill in the rubber art.
[0044] As can be appreciated by one skilled in the art, any of the above recited unvulcanized
rubbers may be the same kind or different kind of rubber that is found in the ground recycled rubber.
[0045] It is to be appreciated that, in order to cure the rubber composition of the present invention,
a sulfur vulcanizing agent is used. Examples of various sulfur vulcanizing agents include, for
example, elemental sulfur (free sulfur) or sulfur donating vulcanizing agents, for example, an amine
disulfide, polymeric polysulfide or sulfur olefin adducts. Preferably, the sulfur vulcanizing agent is
elemental sulfur. The amount of sulfur vulcanizing agent will vary depending on the type of rubber
and the particular type of sulfur vulcanizing agent that is used. Generally speaking, the amount of
sulfur vulcanizing agent ranges from about 0.1 to about 5 phr with a range of from about 0.5 to about
2 being preferred.
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[0046] Conventional rubber additives may be incorporated in the rubber stock of the present
invention. The additives commonly used in rubber stocks include fillers, plasticizers, waxes,
processing oils, peptizers, retarders, antiozonants, antioxidants and the like. The total amount of filler
that may be used may range from about 30 to about 150 phr, with a range of from about 45 to about
100 phr being preferred. Fillers include clays, calcium carbonate, calcium silicate, titanium dioxide
and carbon black. Representative carbon blacks that are commonly used in rubber stocks include,
for example, those with ASTM designations of N110, N121, N220, N231, N234, N242, N293, N299,
S315, N326, N330, M332, N339, N343, N347, N351, N358, N375, N472, N539, N582, N630, N642,
N660, N754, N762, N765, N774, N990 and N991. Plasticizers are conventionally used in amounts
ranging from about 2 to about 50 phr with a range of about 5 to about 30 phr being preferred. The
amount of plasticizer used will depend upon the softening effect desired. Examples of suitable
plasticizers include aromatic extract oils, petroleum softeners including asphaltenes,
pentachlorophenol, saturated and unsaturated hydrocarbons and nitrogen bases, coal tar products,
cumarone-indene resins and esters such as dibutyl phthalate and tricresol phosphate. Typical
peptizers may be, for example, pentachlorothiophenol and dibenzamidophenyl disulfide. Such
peptizers are used in amounts ranging from 0.1 to 1 phr. Common waxes which may be used include
paraffinic waxes and microcrystalline blends. Such waxes are used in amounts ranging from about
0.5 to 3 phr. Materials used in compounding which function as an accelerator-activator includes
metal oxides such as zinc oxide and magnesium oxide which are used in conjunction with acidic
materials such as fatty acid, for example, tall oil fatty acids, stearic acid, oleic acid and the like. The
amount of the metal oxide may range from about 1 to about 14 phr with a range of from about 2 to
about 8 phr being preferred. The amount of fatty acid which may be used may range from about 0
phr to about 5.0 phr with a range of from about 0 phr to about 2 phr being preferred.
[0047] Accelerators are used to control the time and/or temperature required for vulcanization and
to improve the properties of the vulcanizate. In one embodiment, a single accelerator system may be
used; i.e., primary accelerator. The primary accelerator(s) may be used in total amounts ranging from
about 0.5 to about 4, preferably about 0.8 to about 2.0, phr. In another embodiment, combinations of
a primary and a secondary accelerator might be used with the secondary accelerator being used in
a smaller, equal or greater amount to the primary accelerator. Combinations of these accelerators
might be expected to produce a synergistic effect on the final properties and are somewhat better
than those produced by use of either accelerator alone. In addition, delayed action accelerators may
be used which are not affected by normal processing temperatures but produce a satisfactory cure
at ordinary vulcanization temperatures. Vulcanization retarders might also be used. Suitable types of
accelerators that may be used in the present invention are amines, disulfides, guanidines, thioureas,
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thiazoles, thiurams, sulfenamides, dithiocarbamates and xanthates. Preferably, the primary
accelerator is a sulfenamide. If a second accelerator is used, the secondary accelerator is preferably
a guanidine, dithiocarbamate, disulfide or thiuram compound.
[0048] The rubber compounds of the present invention may also contain a cure activator. A
representative cure activator is methyl trialkyl (C8-C10) ammonium chloride commercially available
under the trademark Adogen TM 464 from Sherex Chemical Company of Dublin, Ohio. The amount
of activator may be used in a range of from 0.05 to 5 phr.
[0049] Siliceous pigments may be used in the rubber compound applications of the present
invention, including pyrogenic and precipitated siliceous pigments (silica), although precipitated
silicas are preferred. The siliceous pigments preferably employed in this invention are precipitated
silicas such as, for example, those obtained by the acidification of a soluble silicate, e.g., sodium
silicate. Such silicas might be characterized, for example, by having a BET surface area, as
measured using nitrogen gas, preferably in the range of about 40 to about 600, and more usually in a
range of about 50 to about 300 square meters per gram. The BET method of measuring surface area
is described in the Journal of the American Chemical Society, Volume 60, page 304 (1930). The
silica may also be typically characterized by having a dibutyl phthalate (DBP) absorption value in a
range of about 100 to about 400, and more usually about 150 to about 300 cm/100g.
[0050] Various commercially available silicas may be considered for use in this invention such as,
only for example herein, and without limitation, silicas commercially available from PPG Industries
under the Hi-Sil trademark with designations 210, 243, etc; silicas available from Rhodia, with, for
example, designations of Zeosil 1165MP and Zeosil 165GR and silicas available from Degussa AG
with, for example, designations VN2 and VN3, 3370 etc. Generally speaking, the amount of silica
may range from 5 to 120 phr. The amount of silica will generally range from about 5 to 120 phr.
Preferably, the amount of silica will range from 10 to 30 phr.
[0051] A class of compounding materials known as scorch retarders are commonly used. Phthalic
anhydride, salicylic acid, sodium acetate and N-cyclohexyl thiophthalimide are known retarders.
Retarders are generally used in an amount ranging from about 0.1 to 0.5 phr.
[0052] Conventionally, antioxidants and sometimes antiozonants, hereinafter referred to as
antidegradants, are added to rubber stocks. Representative antidegradants include monophenols,
bisphenols, thiobisphenols, polyphenols, hydroquinone derivatives, phosphites, thioesters, naphthyl
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amines, diphenyl-p-phenylenediamines, diphenylamines and other diaryl amine derivatives, paraphenylenediamines, polymerized trimethyldihydroquinoline and mixtures thereof Specific examples
of such antidegradants are disclosed in The Vanderbilt Rubber Handbook (1990), Pages 282
through 286. Antidegradants are generally used in amounts from about 0.25 to about 5.0 phr with a
range of from about 1.0 to about 3.0 phr being preferred.
[0053] The rubber compound of the present invention may be used as a wire coat or bead coat for
use in a tire. For such purposes, cobalt compounds known in the art to promote the adhesion of
rubber to metal may be blended with the rubber composition. Thus, suitable cobalt compounds
which may be employed include cobalt salts of fatty acids such as stearic, palmitic, oleic, linoleic
and the like; cobalt salts of aliphatic or alicyclic carboxylic acids having from 6 to 30 carbon atoms;
cobalt chloride, cobalt naphthenate, cobalt neodecanoate, cobalt carboxylate and an organo-cobaltboron complex commercially available under the designation Manobond C from Wyrough and Loser,
Inc, Trenton, New Jersey.
[0054] Amounts of cobalt compound which may be employed depend upon the specific nature of
the cobalt compound selected, particularly the amount of cobalt metal present in the compound.
Since the amount of cobalt metal varies considerably in cobalt compounds which are suitable for use,
it is most appropriate and convenient to base the amount of the cobalt compound utilized on the
amount of cobalt metal desired in the finished stock composition.
[0055] The amount of the cobalt compound may range from about 0.1 to 2.0 phr. Preferably, the
amount of cobalt compound may range from about 0.5 to 1.0 phr. When used, the amount of cobalt
compound present in the stock composition should be sufficient to provide from about 0.01 percent
to about 0.35 percent by weight of cobalt metal based upon total weight of the rubber stock
composition with the preferred amounts being from about 0.03 percent to about 0.2 percent by
weight of cobalt metal based on total weight of skim stock composition.
[0056] The sulfur vulcanizable rubber compound is conventionally cured at a temperature ranging,
for example, from about 140 DEG C to 180 DEG C.
[0057] The mixing of the rubber compound can be accomplished by methods known to those
having skill in the rubber mixing art. For example, the ingredients are typically mixed in at least two
stages, namely at least one non-productive stage followed by a productive mix stage. The final
curatives are typically mixed in the final stage which is conventionally called the "productive" mix
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stage in which the mixing typically occurs at a temperature, or ultimate temperature, lower than the
mix temperature(s) of the preceding non-productive mix stage(s). The terms "non-productive" and
"productive" mix stages are well known to those having skill in the rubber mixing art.
[0058] Various articles of manufacture, including tires and industrial products, may contain at least
one component comprised of a rubber composition of this invention. For example, the rubber
composition of this invention may be used in forming a composite with reinforcing material such as in
the manufacture of tires, belts or hoses. Preferably, the composition of the present invention is in the
form of a tire and more specially as a component of a tire, including, for example, one or more of the
tire's tread, wirecoat, beadcoat, sidewall, apex, chafer and plycoat.
[0059] The following Examples are presented to further illustrate, although they are not intended to
be limiting. The parts and percentages are by weight unless otherwise indicated.
EXAMPLE I
[0060] A particulate carbon black composite composed of carbon black and high purity
trithiodipropionic acid (S3) is prepared as follows:
[0061] To a one liter reactor was added 50 grams of a mixture of polythiodipropionic acids which
contained about 85 weight percent 3,3'-trithiodipropionic acid and 50 milliliters of reagent grade
acetone, followed by an addition of 50 grams of particulate N330 carbon black. The mixture was
stirred for several minutes and the acetone then removed from the reactor by evaporation under subatmospheric pressure at about 23 DEG C, or room temperature. The mixture was further dried in a
vacuum oven at about 50 DEG C under a vacuum of about 29 inches of mercury for about 4 hours to
yield a particulate carbon black composite of the high purity trithiodipropionic acid and carbon black
in a form of free-flowing, gray-black colored, granules.
[0062] The resulting particulate (granular) carbon composite contained about 43 weight percent of
trithiodipropionic acid itself based on the total weight of the carbon black composite.
EXAMPLE II
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[0063] Four rubber formulations were prepared to compare and contrast a significance of two
different levels of trithiodipropionic acid with ground recycled rubber and identified herein as
Samples C and D, with Samples A and B being Control Samples.
[0064] Each rubber formulation contained 70 parts by weight of cis 1,4-polybutadiene rubber and
30 parts by weight styrene/butadiene rubber. Each rubber formulation also contained the same
conventional amounts of processing oil, peptizer, fatty acids, antidegradants, waxes, zinc oxide,
primary and secondary accelerators and sulfur. Each formulation differed by the additional
ingredients listed in Table 1. The rubber formulations were prepared in a two-stage internal rubber
mixing procedure, namely, by mixing the ingredients in an internal rubber mixer to a temperature of
about 150 DEG C, removing and cooling the mixture to below 40 DEG C and then mixing the sulfur
and sulfur vulcanization accelerators therewith in an internal rubber mixture to a temperature of about
108 DEG C.
[0065] Control Sample A was comprised of a rubber composition without any particulate pre-sulfur
vulcanized rubber and without said particulate (granular) carbon black composite of carbon black
and high purity trithiodipropionic acid prepared in Example I.
[0066] Control Sample B was comprised of a rubber composition which contained a particulate
pre-sulfur vulcanized rubber composition (scrap rubber) but did not contain said particulate carbon
black composite of carbon black and high purity trithiodipropionic acid prepared in Example I.
[0067] Sample C and Sample D contained both the particulate pre-sulfur vulcanized rubber
composition (scrap rubber) and a sufficient amount of carbon black composite prepared by Example
I to provide 0.5 and 1.5 parts by weight of trithiodipropionic acid per 100 parts of the added cis 1,4polybutadiene rubber and styrene/butadiene rubber.
[0068] The additional ingredients for the rubber compositions are illustrated in the following Table 1.
Id=Table 1 Columns=5
Head Col 1:
Head Col 2 to 5: Parts
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SubHead Col 1: Material
SubHead Col 2: Sample A
Control
SubHead Col 3: Sample B
Control
SubHead Col 4: Sample C
SubHead Col 5: Sample D
SubHead Col 6: Non-Productive Mixing for about minutes to about 150 DEG C
Polybutadiene rubber
3030303
Styrene/butadiene rubber
70707070
Recycle rubber
0202020
Trithiodipropionic acid
000.51.5
Cis 1,4-polybutadiene rubber obtained as Budene 1254 from The Goodyear Tire & Rubber
Company as a rubber/oil mixture weight ratio of 30/7.5 and reported in Table 1 on a dry weight of
rubber basis.
Styrene/butadiene rubber having a styrene content of about 12 percent obtained as PLF 1712 from
The Goodyear Tire & Rubber Company as a rubber/oil mixture weight ratio of 70/26.25 and reported
in Table 1 on a dry weight of rubber basis.
Ground, sulfur pre-vulcanized rubber having a particle size of about 80 mesh (e.g. about 180
microns) obtained as GF80 from the Rouse Company. The GF80 recycle rubber (particulate, ground
sulfur vulcanized rubber) contained about 88 percent by weight of particles that pass through 100
mesh, 95 percent by weight of particles that pass through 80 mesh and 100 percent by weight of
particles that pass through a 60 mesh screen. A thermal gravimetric analysis (TGA) analysis for the
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GF80 recycle rubber is about 14 percent by weight volatiles, about 7 percent ash, about 30 percent
carbon black and 50 percent rubber.
Particulate (granular) carbon black composite of N330 carbon black and high purity
trithiodipropionic acid as prepared in Example I. The acid composition was composed of about 85
weight trithiodipropionic acid, about 10 weight percent dithiodipropionic acid and about 5 weight
percent of tetrathiodipropionic acid. The trithiodipropionic acid is reported in Table 1 in terms of parts
by weight of the composite provided per 100 parts by weight of the added polybutadiene and
styrene/butadiene rubbers reported in Table 1.
EXAMPLE III
[0069] The Samples A through D were cured at a temperature of about 150 DEG C and the
resulting cure properties of the Samples reported in the following Table 2 were determined using a
Monsanto oscillating disc rheometer which was operated at a temperature of 150 DEG C and 100
cycles per minute. A description of oscillating disc rheometers can be found in The Vanderbilt
Rubber Handbook, edited by Robert O. Ohm (Norwalk, Conn., R. T. Vanderbilt Company, Inc., 1990),
Pages 554 through 557. The use of this cure meter and standardized values read from the curve are
specified in ASTM D-2084. A typical cure curve obtained on an oscillating disc rheometer is shown
on Page 555 of the 1990 edition of The Vanderbilt Rubber Handbook.
[0070] In such an oscillating disc rheometer, compounded rubber samples are subjected to an
oscillating shearing action of constant amplitude. The torque of the oscillating disc embedded in the
stock that is being tested that is required to oscillate the rotor at the vulcanization temperature is
measured. The values obtained using this cure test are considered herein as being significant since
changes in the rubber by varying the ingredients are very readily observed. It is considered herein
that it is normally desirable and advantageous for the rubber composition to exhibit a relatively a fast
rate of vulcanization.
[0071] The following Table 2 reports cure properties there were determined from cure curves that
were obtained for the rubber stocks that were prepared as Samples A-D of Example II. These
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properties include a torque minimum, a torque maximum, the differences between maximum torque
and minimum torque (delta torque), final torque minutes to 1 percent of the torque increase (t1),
minutes to 25 percent of the torque increase (T25), minutes to 50 percent of the torque increase
(T50), minutes to 80 percent of the torque increase (T80) and minutes to 90 percent of the torque
increase (T90).
[0072] The term "ODR" relates to the test instrument used for obtaining the cure behavior date,
namely a commercially available Oscillating Disk Rheometer.
Id=Table 2 Columns=5
Head Col 1:
Head Col 2: Control Sample A
Head Col 3: Control Sample B
Head Col 4: Sample C With GF80
Head Col 5: Sample D With GF80
SubHead Col 1: ODR (Temp 150 DEG C)
SubHead Col 2: Without GF80
SubHead Col 3: With GF80
SubHead Col 4: 0.5 Parts S3
SubHead Col 5: 1.5 Parts S3
Minimum torque (MPa)10.2710.4111.4211.51
Maximum torque (MPa)36.5232.8637.0838.66
Delta torque26.2522.4525.6527.15
Final torque (MPa)36.0932.5536.9538.58
T (1)5.385.285.735.26
T 257.136.887.87.51
T 508.218.119.59.66
T 8010.9311.113.9315.3
T 9013.6813.9818.220.36
100% modulus (MPa)1.731.561.761.93
300% modulus (MPa)8.626.947.778.62
Tensile strength (MPa)15.7514.2714.2713.66
Elongation (%)488518491449
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SubHead Col 1 to 5 AL=L: Shore A Hardness
23 DEG C62.761.464.766.4
100 DEG C53.551.353.855.4
SubHead Col 1 to 5 AL=L: Rebound
23 DEG C4040.342.642.7
100 DEG C55.152.553.553.9
Peel adhesion (MPa?)67826959
Dispergrader white area4.27.39.69.9
DIN abrasion (cm loss)90939598
Mooney (ML 1+4)76828686
[0073] From Table 2, it can be seen from properties of Control Sample B that the addition of 20
parts of GF 80 recycle rubber to Sample A significantly degraded the stiffness, hardness, delta
torque and 100 percent and 300 percent modulus properties of the rubber composition. This
reduction in such properties is considered herein to be significant because various components of
tires, such as for example treads, normally upon one or more of such physical properties for
maintaining their durability, particularly under working conditions.
[0074] From Table 2, it can be seen from the properties of Sample C and Sample D that the
addition of from 0.5 to 1.5 parts of the thiodipropionic acid to the composition Sample B which
contained the GF 80 pre-vulcanized rubber additive (recycle rubber) resulted in the Samples
regaining, or substantially maintaining, the aforesaid physical properties of Control Sample A such as
stiffness, delta torque and 100 percent and 300 percent modulii. This is considered herein to be
important because of the aforesaid significance of such physical properties.
[0075] Accordingly, the rubber composition which contains a particulate sulfur pre-vulcanized
rubber additive (recycle rubber) in combination with the trithiodipropionic acid is therefore
considered herein to be novel and inventive because apparently a strong interaction between
recycle rubber and the carbon black composite of carbon black and trithiodipropionic acid resulted
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in a rubber composition with retained physical properties, such as delta torque for the state of cure,
as well as modulus and hardness.
[0076] While certain representative embodiments and details have been shown for the purpose of
illustrating the invention, it will be apparent to those skilled in this art that various changes and
modifications may be made therein without departing from the spirit or scope of the invention.Claims:
1. A process of preparing a sulfur vulcanizable rubber composition characterized by:
A. preparing a pre-blend by homogeneously blending
1. particles of a sulfur vulcanized, diene-based rubber composition, together with
2. high purity trithiodipropionic acid and particles of carbon black, or
3. particles of a carbon black composite comprised of carbon black and high purity
trithiodipropionic acid, having a weight ratio of said high purity trithiodipropionic acid to carbon black
in a range of from 1/10 to 10/1 and
wherein said high purity trithiodipropionic acid having the general Formula (I): (I) HO2CCH2CH2 Sn - CH2CH2CO2H wherein n is a value of from 2 to 5 and wherein at least 80 percent of n is 3,
wherein the amount of said carbon black composite is sufficient to provide from 0.18 to 10 parts
by weight of trithiodipropionic acid per 100 parts by weight of diene-based rubber contained in said
sulfur vulcanized rubber composition, and wherein said particles of sulfur vulcanized rubber
composition is of a particle size of less than 420 microns;
(B) mixing one to 40 parts by weight of said pre-blend with 100 parts by weight of at least one
unvulcanized hydrocarbon diene-based, sulfur vulcanizable rubber to form a rubber composition
comprised of said unvulcanized rubber and said pre-blend.
2. The process of claim 1 characterized in that said high purity trithiodipropionic acid is a blend of
polythiodipropionic acids comprised of from 80 to 90 weight percent of said trithiodipropionic acid, a
maximum of 20 weight percent dithiopropionic acid and a maximum of 10 weight percent
tetrathiopropionic acid, based on said polythiodipropionic acid blend.
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3. The process of either of the preceding claims wherein sulfur is mixed with said particulate preblend prior to said blending with said unvulcanized diene-based rubber.
4. The process of any of the preceding claims wherein one to 40 parts by weight of said particulate
pre-blend is mixed with sulfur and 100 parts by weight of said unvulcanized hydrocarbon dienebased rubber.
5. A rubber composition prepared by the process of any of the preceding claims wherein said rubber
composition is sulfur vulcanized in a suitable mold at a temperature in a range of 140 DEG C to 180
DEG C.
6. An article of manufacture characterized by containing at least one component as a rubber
composition prepared according to the process of any of the preceding claims 1 through 4.
7. An article of manufacture characterized by containing at least one component of a sulfur
vulcanized rubber composition of claim 5.
8. A tire characterized by containing at least one component which comprises a rubber composition
prepared by the process of any of the preceding claims 1 through 4.
9. A tire characterized by containing at least one component comprised of a sulfur vulcanized rubber
composition of claim 5.
10. A tire characterized by having a tread of a rubber composition comprised of the sulfur vulcanized
rubber composition of claim 5.
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13. EP1279698 - 29.01.2003
COATED RECYCLED VULCANIZED RUBBER PARTICLES AND PROCESS FOR PREPARING SAME
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=EP1279698
Inventor(s):
KEYEUX JEAN-CLAUDE [BE] (--)
Applicant(s):
KEYEUX JEAN-CLAUDE [BE] (--)
IP Class 4 Digits: C08J; C08L
IP Class:
C8L19/00; C8J11/06
E Class: C08J11/06; C08L19/00B+B2A
Application Number:
EP20020447144 (20020724)
Priority Number: BE20010000507 (20010725)
Family: EP1279698
Equivalent:
BE1014315
Cited Document(s):
WO9320132; DE4102237; DE19607281; US4795603
Abstract:
GRANULATED MATERIAL BASED ON PARTICLES OF USED VULCANIZED RUBBER (I) IS COATED
WITH PARTICLES BASED ON AT LEAST ONE THERMOPLASTIC MATERIAL (II) WHICH HAS BEEN
RECYCLED AT LEAST ONCE. AN INDEPENDENT CLAIM IS ALSO INCLUDED FOR A METHOD FOR
THE PRODUCTION OF THIS MATERIAL BY HEATING THE THERMOPLASTIC(S) (II) IN A MIXER,
ADDING THE RUBBER PARTICLES (I) AND GRANULATING THE COATED PRODUCT.Description:
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[0001] La prйsente invention est relative а un granulat а base de particules de caoutchouc
vulcanisй usagй.
[0002] Ces derniиres annйes, le recyclage s'est imposй comme une solution d'avenir. Il permet,
en effet, de reconditionner des produits possйdant un fort potentiel йnergйtique tout en йvitant de
les incinйrer, supprimant ainsi les rejets de CO2 qui dйcoulent de la combustion.
[0003] Nйanmoins, certaines matiиres produites, en trиs grande quantitй, comme les
caoutchoucs vulcanisйs des pneus, sont de par leur nature difficilement recyclables. Ces matiиres
subissent, en effet, d'importantes restructurations molйculaires lors de la vulcanisation qui
empкchent toute rйversibilitй de leur йtat.
[0004] D'autres matiиres, comme les thermoplastiques, bien qu'ayant un йtat rйversible, sont
produites en telle quantitй que les filiиres actuelles de recyclage ne sont pas suffisantes pour en
absorber et en reconditionner toute la production.
[0005] De plus, les techniques de recyclage, du fait de la diversitй des produits au sein d'un
mкme groupe de matiиres, sont extrкmement difficiles а maоtriser et а mettre en oeuvre.
[0006] L'invention a donc pour but de prйsenter une solution а ce problиme, en permettant le
recyclage de deux groupes de matiиres : les caoutchoucs vulcanisйs usagйs et les matiиres
thermoplastiques, de maniиre а proposer un nouveau produit composй de matйriaux issus d'une
maniиre prйpondйrante, de prйfйrence totalement, du recyclage. Dans ce but, elle prйvoit aussi
un procйdй de fabrication de ce nouveau produit.
[0007] Pour rйsoudre ces problиmes, il est prйvu, suivant l'invention, un granulat а base de
particules de caoutchouc vulcanisй, usagй, comprenant un enrobage des particules а base d'au
moins une matiиre thermoplastique, au moins une fois recyclйe. Ladite invention permet donc de
recycler а la fois des particules de caoutchouc vulcanisй usagй, issu des pneumatiques usagйs
des mйnages ou des dйchets de la production de pneus, et des matiиres thermoplastiques issues
par exemples des bouteilles alimentaires, flacons de dйtergent, pare-chocs de voiture, ...
[0008] Ce granulat, une fois produit, pourra servir par exemple de matiиre premiиre de moulage
d'objets tels que des tuiles ou de matiиre premiиre pour des objets laminйs tels que des panneaux
d'insonorisation.
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[0009] Suivant une forme de rйalisation de l'invention, le granulat comprend un composant
ajustant un indice de fluiditй de ladite au moins une matiиre thermoplastique servant а l'enrobage.
[0010] Lesdites matiиres thermoplastiques, issues du recyclage, ont des qualitйs et des
caractйristiques variables car elles proviennent de dйchets issus de diffйrentes productions et
produits. Cette hйtйrogйnйitй de produit, lorsqu'elle n'est pas contrфlйe et rйgulйe, introduit
inйvitablement des variations sur la qualitй de la fabrication de granulat. Ledit composant, ajustant
l'indice de fluiditй, permet de garantir au produit une qualitй constante malgrй les variations de
l'indice de fluiditй desdites matiиres thermoplastiques.
[0011] A titre de composant ajustant l'indice de fluiditй, on peut prйvoir un composй issu d'une
rйaction d'au moins un peroxyde, par exemple du peroxyde de basoyle, avec ladite au moins une
matiиre thermoplastique. Comme autre type de composant ajustant l'indice de fluiditй on peut
envisager par exemple une huile minйrale. Avantageusement cette huile minйrale sera
prйalablement йpongйe par un mйlange maоtre absorbant qui peut кtre saturй jusqu'а 25 %.
[0012] Les matiиres thermoplastiques recyclйes peuvent кtre par exemple des matiиres
thermoplastiques, en particulier des homopolymиres et copolymиres polyolйfiniques et leurs
mйlanges, les homopolymиres et copolymиres de propylиne et leurs mйlanges.
[0013] Le caoutchouc vulcanisй, recyclй, peut avantageusement кtre а base d'un mйlange de
gomme naturelle et de gomme synthйtique qui a йtй vulcanisй. Il est йvidemment important de
veiller а maintenir une proportion constante entre ces deux types de gommes en fonction de la
provenance du caoutchouc utilisй.
[0014] Les caoutchoucs sont prйalablement broyйs jusqu'а une taille de particules infйrieure а 2
mm, avantageusement de 0,5 а 1 mm.
[0015] Suivant une forme de rйalisation avantageuse de l'invention le granulat comprend 40 а
50 % en poids de particules de caoutchouc vulcanisй usagй et 55 а 45 % en poids de ladite au
moins une matiиre thermoplastique, le restant йtant formй d'un pourcentage d'adjuvant et produit
de dйgradation. Comme adjuvants, on peut par exemple envisager, outre un composant ajustant
l'indice de fluiditй, des stabilisants aux U.V., des colorants, des agents rendant le matйriau
rйsistant au feu, etc.
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[0016] Avantageusement la densitй du granulat obtenu varie entre 0,9 et 1,4 kg par dm.
[0017] Lesdits granulats pourront, suivant l'invention, кtre fabriquйs par un procйdй tel que
dйcrit ci-dessous. Ladite matiиre thermoplastique issue du recyclage, par exemple de bouteilles
alimentaires, est chauffйe et ramollie de maniиre а avoir une matiиre plus homogйnйisable. Le
chauffage permet, en effet, au moins а une partie des polymиres ou copolymиres de la matiиre
thermoplastique de retourner а l'йtat fluide, ce qui favorisera les contacts avec lesdites particules
de caoutchouc vulcanisй.
[0018] Ladite matiиre thermoplastique, une fois chauffйe est introduite dans un dispositif de
mйlange, par exemple une extrudeuse. Par aprиs, on y introduit lesdites particules de caoutchouc
vulcanisй usagй. Lesdites particules de caoutchouc usagй vont alors кtre enrobйes durant le
malaxage et vont subir ensuite, а la sortie du dispositif de mйlange, une granulation.
[0019] Suivant un mode perfectionnй de rйalisation de l'invention, le chauffage de ladite au moins
une matiиre thermoplastique est effectuй а une tempйrature supйrieure а sa fluidification et en ce
que le mйlange entre ladite au moins une matiиre thermoplastique et les particules de caoutchouc
a lieu а une tempйrature infйrieure а la tempйrature de carbonisation du caoutchouc.
[0020] D'autres formes de rйalisation de granulat et du procйdй de fabrication sont indiquйes
dans les revendications annexйes.
[0021] L'invention va а prйsent кtre dйcrite de maniиre plus dйtaillйe а l'aide d'un exemple de
rйalisation non limitatif.
Exemple
[0022] On utilise des particules de caoutchouc vulcanisй usagй issues de pneus de voiture
automobile dйchiquetйs, broyйs et tamisйs de maniиre а obtenir des particules ayant une taille
comprise entre 0,5 et 1 mm. Des pneus de voiture ayant une composition (dйterminйe...) permettant
la rйalisation de cet exemple.
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[0023] Comme matiиres thermoplastiques on utilise du polypropylиne issu de pare-chocs de
voiture dйchiquetйs, conditionnйs sous forme de paillettes.
[0024] Les paillettes а concurrence de 50 % en poids du futur mйlange sont chauffйes а une
tempйrature de 210 DEG C pendant un temps dйterminй suivant la puissance de chauffe utilisйe,
dans un fourreau muni de rйsistances chauffantes et d'une vis mйlangeuse. L'indice de fluiditй est
alors contrфlй а la sortie du fourreau. Dans le cas oщ cet indice de fluiditй est infйrieur а 10, une
addition d'huile minйrale, par exemple de 2 % en poids, est faite а la matiиre thermoplastique
chauffйe.
[0025] De mкme, les composants colorants et ignifugeants, dans ce cas-ci 1 % en poids de noir
de carbone, et des composants ignifugeants, dans ce cas-ci 2 % en poids de gamma-mйlamine,
sont additionnйs а la matiиre thermoplastique chauffйe.
[0026] Ensuite, les particules de caoutchouc vulcanisй usagй sont dйversйes а concurrence de
45 % en poids du mйlange dans la trйmie permettant l'accиs au fourreau, dont la tempйrature est
alors maintenue infйrieure а 210 DEG C de maniиre а ne pas risquer de carboniser les particules
de caoutchouc vulcanisй usagй.
[0027] Le mйlange est ensuite passй dans un granulateur. Le granulat ainsi obtenu aura une
densitй de 1 kg/dm et conviendra particuliиrement bien comme matйriau pour effectuer un
moulage, d'objets tels que des tuiles, des panneaux de recouvrement, etc.
[0028] Il doit кtre entendu que la prйsente invention n'est en aucune faзon limitйe а la forme de
rйalisation dйcrite ci-dessus et que bien des modifications peuvent y кtre apportйes sans sortir du
cadre des revendications annexйes.Claims:
1. Granulat а base de particules de caoutchouc vulcanisй usagй, caractйrisй en ce qu'il
comprend un enrobage des particules а base d'au moins une matiиre thermoplastique, recyclйe au
moins une fois.
2. Granulat suivant la revendication 1, caractйrisй en ce qu'il comprend un composant ajustant un
indice de fluiditй de ladite au moins une matiиre thermoplastique servant а l'enrobage.
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3. Granulat suivant la revendication 2, caractйrisй en ce qu'il comprend а titre de composant
ajustant l'indice de fluiditй un composй issu d'une rйaction d'au moins un peroxyde avec ladite au
moins une matiиre thermoplastique.
4. Granulat suivant la revendication 2, caractйrisй en ce que ledit composй ajustant un indice de
fluiditй de ladite au moins une matiиre thermoplastique est une huile minйrale.
5. Granulat suivant la revendication 2, caractйrisй en ce que ladite au moins une matiиre
thermoplastique est choisie parmi le groupe constituй des homopolymиres et copolymиres
polyolйfiniques et de leur mйlange.
6. Granulat suivant la revendication 5, caractйrisй en ce que ladite matiиre thermoplastique est
choisie parmi le groupe constituй des homopolymиres et copolymиres а base de propylиne et de
leur mйlange.
7. Granulat suivant l'une des revendications 1 а 6, caractйrisй en ce que lesdites particules de
caoutchouc vulcanisй usagй ont un diamиtre infйrieur а 2 mm.
8. Granulat suivant l'une des revendications 1 а 7, caractйrisй en ce que le granulat comprend 40
а 50 % en poids de particules de caoutchouc vulcanisй usagй et 55 а 45 % en poids de ladite au
moins une matiиre thermoplastique, le restant йtant formй d'un pourcentage d'adjuvant et de
produit de dйgradation.
9. Granulat suivant l'une des revendications 1 а 8, caractйrisй en ce qu'il comprend au moins un
adjuvant choisi parmi le groupe constituй des composйs stabilisateurs UV, des composйs
antioxydants, des composйs ignifugeants, des composйs plastifiants, des composйs colorants et
de leur mйlange.
10. Procйdй de fabrication de granulat а base de particules de caoutchouc vulcanisй usagй,
lequel comprend les йtapes suivantes :
chauffage d'au moins une matiиre thermoplastique, au moins une fois recyclйe,
introduction dans un dispositif de mйlange de ladite au moins une matiиre thermoplastique,
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introduction dans ledit dispositif de mйlange desdites particules de caoutchouc vulcanisй usagй,
avec enrobage de ces dites particules par ladite matiиre thermoplastique chauffйe, et
granulation des particules de caoutchouc vulcanisй usagй, enrobйes.
11. Procйdй de fabrication de granulat а base de particules de caoutchouc vulcanisй usagй
suivant la revendication 10, lequel comprend en outre :
une vйrification de la viscositй de ladite au moins une matiиre thermoplastique, au moins une fois
recyclйe, chauffйe, et
un ajout de composant ajustant l'indice de fluiditй destinй а maintenir une viscositй constante de
ladite matiиre thermoplastique, une fois chauffйe.
12. Procйdй de fabrication de granulat а base de particules de caoutchouc vulcanisй usagй
suivant l'une des revendications 10 et 11 comprenant une extrusion en granulй desdites particules
de caoutchouc vulcanisй usagй enrobйes de ladite au moins une matiиre thermoplastique.
13. Procйdй de fabrication de granulat а base de particules de caoutchouc vulcanisй usagй
suivant l'une des revendications 10 et 11, caractйrisй en ce qu'il comprend un passage desdites
particules de caoutchouc vulcanisй usagй enrobйes de ladite au moins une matiиre
thermoplastique au travers d'une filiиre.
14. Procйdй suivant l'une quelconque des revendications 10 а 13, caractйrisй en ce que le
chauffage de ladite au moins une matiиre thermoplastique est effectuй а une tempйrature
supйrieure а sa fluidification et en ce que le mйlange entre ladite au moins une matiиre
thermoplastique et les particules de caoutchouc a lieu а une tempйrature infйrieure а la
tempйrature de carbonisation du caoutchouc.
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14. EP1359183 - 02.10.2003
METHOD OF VULCANIZED BONDING OF HEAT-RESISTANT RUBBER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=EP1359183
Inventor(s):
KANBE SHINOBU [JP] (--)
Applicant(s):
TOKAI RUBBER IND LTD [JP] (--)
IP Class 4 Digits: C08F
IP Class:
C8F120/44
E Class: C08J5/12+L21/00
Application Number:
US20030393928 (20030320)
Priority Number: JP20020090717 (20020328)
Family: EP1359183
Equivalent:
JP2003286351
Abstract:
THE PRESENT INVENTION PROVIDES A METHOD OF VULCANIZED BONDING OF HEAT
RESISTANT RUBBER. VULCANIZED BONDING OF A HYDROGENATED ACRYLONITRILE
BUTADIENE RUBBER (H-NBR) AND AN ACRYLIC RUBBER (ACM) COMPRISES A STEP FOR
MIXING ZINC OXIDE (ZNO) AND MAGNESIUM OXIDE (MGO) AS ACID ACCEPTORS INTO NONVULCANIZED H-NBR; AND A STEP FOR THE PEROXIDE VULCANIZATION OF THE H-NBR AT THE
SAME TIME AS THE VULCANIZED BONDING OF THE ACM, WHICH IS OF AN EPOXY CROSSLINKING TYPE. THUS, HYDROGENATED ACRYLONITRILE BUTADIENE RUBBER (H-NBR) AND
ACRYLIC RUBBER (ACM) ARE VULCANIZED BONDED SECURELY WHILE ALSO PROVIDING HEAT
RESISTANCE.Description:
BACKGROUND OF THE INVENTION
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[0001] 1. Field of the Invention
[0002] The present invention provides a method of vulcanized bonding of heat-resistant rubber. More
specifically, the present invention provides a method of vulcanized bonding of heat-resistant rubber
to achieve strong vulcanized bonding of hydrogenated acrylonitrile butadiene rubber (H-NBR) and
acrylic rubber (ACM) while providing adequate heat resistance and wear resistance.
[0003] 2. Description of the Related Art
[0004] In recent years, there has been a demand for fuel hoses with heat resistance and fuel
resistance. For example, due to exhaust gas countermeasures, front wheel drive, and the like, the
temperature inside the engine housing of automobiles has become more severe. Due to the
advances of low fuel consumption, there has been a dramatic rise in the level of heat resistance
demanded by the peripheral parts of diesel engines. As a result, diesel fuel hoses, for example,
require high heat resistance at around 150[deg.] C. for 500 hours.
[0005] Methods of using acrylonitrile butadiene rubber (NBR) or acrylic rubber (ACM) in the inner
pipe of the fuel hose do not always adequately satisfy the heat resistance and fuel resistance
requirements. These methods are particularly inadequate for diesel fuel hoses. Adequate heat and
fuel resistance is achieved by using fluorine rubber (FKM). However, FKM is very expensive, and
there are problems with inadequate cold resistance and the inadequate workability of the nonvulcanized molded body.
[0006] On the other hand, of the nitrile rubbers, H-NBR has excellent heat resistance, fuel resistance,
and cold resistance. The butadiene units of NBR are completely or partially hydrogenated in H-NBR.
Although H-NBR is relatively expensive, the cost is more reasonable compared to FKM. By using the
relatively expensive H-NBR in the inner layer of the inner pipe of the hose and by using an
inexpensive rubber having some heat resistance and fuel resistance (such as ACM, preferably) for
the outer layer of the inner pipe of the hose, the inner layer of the inner pipe of the hose can be
thinner. The amount of H-NBR is reduced, and this construction is more practical.
[0007] References such as Japanese Laid-Open Patent Publication No. 9-124845, Japanese LaidOpen Patent Publication No. 9-112756, and Japanese Laid-Open Patent Publication No. 2001279021 disclose hoses using H-NBR mixtures and H-NBR mixtures for use in hoses, and the like. In
addition, Japanese Laid-Open Patent Publication No. 9-325332 discloses a hose having an
innermost layer of H-NBR and an outer layer of ACM which is vulcanized and molded to form a
unitary body.
[0008] When constructing a heat resistant fuel hose having a rubber inner pipe with an inner layer of
H-NBR and an outer layer of ACM in the inner pipe, the inner layer in the inner pipe needs to be
securely bonded with the outer layer in the inner pipe, preferably by vulcanized bonding. At the
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same time, there is also a need to improve the heat resistance of the rubber inner pipe as much as
possible.
[0009] Japanese Laid-Open Patent Publication No. 9-124845, Japanese Laid-Open Patent
Publication No. 9-112756, and Japanese Laid-Open Patent Publication No. 2001-279021 described
above disclose ways to improve the H-NBR mixtures according to each of their technical objectives.
Ways to improve heat resistance in general are also disclosed in these references. However, the
references do not disclose ways to improve bonding between H-NBR and ACM while simultaneously
improving the heat resistance of H-NBR.
[0010] Japanese Laid-Open Patent Publication No. 9-325332 described above discloses a hose
having vulcanized bonding between the H-NBR layer and the ACM layer by peroxide vulcanization of
H-NBR. The peroxide vulcanization is considered to be beneficial for improving the heat resistance of
H-NBR. However, according to the research of the present inventor, the carboxyl group cross-linking
type of ACM used in the disclosed invention does not always achieve strong vulcanized bonding with
H-NBR. In addition, the method of peroxide vulcanization of H-NBR does not particularly improve the
bonding of the two layers.
[0011] Furthermore, although the mixing of silica filler into H-NBR may improve the vulcanized
bonding with the adjacent ACM layer, the workability of the non-vulcanized molded body remains
inadequate.
SUMMARY OF THE INVENTION
[0012] The present invention provides a method of secure vulcanized bonding of H-NBR and ACM
while providing heat resistance and wear resistance.
[0013] An embodiment of the present invention provides a method of vulcanized bonding of heatresistant rubber. The method of vulcanized bonding of a hydrogenated acrylonitrile butadiene rubber
(H-NBR) and an acrylic rubber (ACM) comprises a step for mixing zinc oxide (ZnO) and magnesium
oxide (MgO) as acid acceptors into non-vulcanized H-NBR; and a step for simultaneously performing
peroxide vulcanization of H-NBR and vulcanized bonding of ACM of an epoxy cross-linking type.
[0014] The method of vulcanized bonding of heat resistant rubber according to the embodiment
described above involves the vulcanized bonding of H-NBR, which has excellent heat resistance,
fuel resistance, cold resistance, and the like, with ACM, which has a constant heat resistance and
fuel resistance and is relatively inexpensive. Thus, the present invention provides a layered heat
resistant rubber with excellent heat resistance, fuel resistance, and the like without too much added
expense. Furthermore, due to the peroxide vulcanization of the H-NBR, heat resistance is improved
even more.
121/425
[0015] Additionally, ZnO and MgO, which are acid acceptors, are mixed with the H-NBR, which is to
be peroxide vulcanized, and the ACM, which is to be vulcanized bonded with H-NBR, is an epoxy
cross-linking type of ACM. Thus, H-NBR and ACM are securely vulcanized bonded. Although the
reason for this is still not clear, the inventor suspects that the MgO, which is an acid acceptor, forms
a pseudo-cross link with the epoxy cross-link type ACM, thereby increasing the bonding strength. By
also using ZnO, which is also an acid acceptor, a good compression set resistance is achieved.
[0016] Japanese Laid-Open Patent Publication No. 9-124845 mentioned above discloses a step for
mixing ZnO or MgO into H-NBR. Additionally, Japanese Laid-Open Patent Publication No. 2001279021 discloses an embodiment in which ZnO and MgO are mixed into H-NBR. However, these
references disclose mixtures which are unrelated to the vulcanized bonding of H-NBR and ACM and
do not disclose the contribution of these acid acceptors to the vulcanized bonding of H-NBR and
ACM.
[0017] According to another embodiment of the present invention, the mixing amount of ZnO into HNBR as described above is 2 phr (weight parts per hundred weight parts of rubber) or greater and
the mixing amount of MgO is 4 phr or greater.
[0018] Although the mixing amount of ZnO and MgO in H-NBR is not restricted, the mixing amount of
ZnO is preferably 2 phr or greater and the mixing amount of MgO is preferably 4 phr or greater.
When the mixing amount of MgO is less than 4 phr, the strength of the vulcanized bond with ACM
may be inadequate from a practical standpoint. Additionally, when the mixing amount of ZnO is less
than 2 phr, the compression set resistance of H-NBR may be inadequate from a practical standpoint.
[0019] According to another embodiment of the present invention, the mixing amount of ZnO in HNBR as described above is 2-10 phr, and the mixing amount of MgO is 4-15 phr.
[0020] More preferably, the mixing amounts of ZnO and MgO in H-NBR are 2-10 phr for ZnO and 415 phr for MgO. If there is an amount of ZnO and MgO outside of this range, the workability or the
like of the non-vulcanized molding body may be unsatisfactory.
[0021] According to another embodiment of the present invention, a vulcanizing agent or
vulcanization accelerator such as ammonium salt is mixed into the ACM described above.
[0022] When ammonium salt is mixed into ACM as the vulcanizing agent or vulcanization accelerator
as described above, the vulcanized bond strength of the ACM and H-NBR is further improved. The
improvement is most likely the result of an increased speed of vulcanization.
[0023] According to another embodiment of the present invention, the vulcanizing agent or
vulcanization accelerator described above is a compound or compound group of one of the
following (1)-(3) or a combination of two or more of any of (1)-(3):
[0024] (1) ammonium benzoate;
[0025] (2) isocyanuric acid, quaternary ammonium salt, and diphenyl urea; and
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[0026] (3) imidazole, thiourea, and quaternary ammonium salt.
[0027] Although the type of vulcanizing agent or vulcanization accelerator used as described above
is not restricted, it is preferably a compound or compound group in one of (1)-(3) or a combination of
two or more of any of (1)-(3).
[0028] According to another embodiment of the present invention, H-NBR and ACM described
above are used in the inner pipe of a hose as a laminated body with an inner layer of H-NBR and an
outer layer of ACM.
[0029] When H-NBR and ACM are used in the inner pipe of a hose as a laminated body with an inner
layer of H-NBR and an outer layer of ACM, excellent heat resistance, oil resistance, fuel resistance,
and the like are provided, thereby resulting in an extremely good heat resistant hose having a rubber
inner pipe in which the inner layer and outer layer have a secure vulcanized bond.
[0030] According to another embodiment of the present invention, the hose described above is a fuel
hose, oil hose, or air hose.
[0031] The heat resistant hose described above has various uses and is not restricted to any
particular use. However, as described above, because the inside of the engine housing of an
automobile experiences extremely hot temperatures due to exhaust gas countermeasures, front
wheel drive, and the like, the hose is preferably a fuel hose. Because of its heat resistance and oil
resistance, the hose can also be an oil hose or an air hose.
[0032] According to another embodiment of the present invention, the fuel hose described above is a
diesel fuel hose.
[0033] The fuel hose described above is especially useful as a diesel fuel hose for use in diesel
engines. There has been a dramatic increase in the level of heat resistance demanded of the
peripheral parts of diesel engines due to designs for low fuel consumption and the like.
[0034] The above and other advantages of the invention will become more apparent in the following
description.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Method of Vulcanized Bonding of Heat Resistant Rubber
[0036] The present invention provides a method for vulcanized bonding of hydrogenated acrylonitrile
butadiene rubber (H-NBR) and acrylic rubber (ACM). Zinc oxide (ZnO) and magnesium oxide (MgO)
are mixed into H-NBR as acid acceptors, and H-NBR is peroxide vulcanized. At the same time, ACM
of an epoxy cross-linking type is vulcanized bonded to H-NBR. More preferably, H-NBR and ACM
are vulcanized bonded as a layered body which is flat, tube-shaped, or the like to construct a
vulcanized-bonded layered body of this shape. When constructing a tube-shaped vulcanizedbonded layered body, it is preferable to have H-NBR as the inner layer and ACM as the outer layer.
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[0037] H-NBR
[0038] H-NBR used in the present invention is an unsaturated nitrile-conjugated diene copolymer
rubber which is completely or partially hydrogenated. The H-NBR in the present invention comprises
(a) a unit portion of unsaturated nitrile, (b) a unit portion of conjugated diene, and (c) a unit portion in
which a unit portion of an ethylene unsaturated monomer other than unsaturated nitrile and/or the unit
portion of conjugated diene is hydrogenated. The composition ratio of H-NBR for (a) the unit portion
of unsaturated nitrile, (b) the unit portion of conjugated diene, and (c) the unit portion comprising the
hydrogenated unit portion of an ethylene unsaturated monomer other than unsaturated nitrile and/or
the unit portion of conjugated diene is not restricted. However, with respect to heat resistance, fuel
resistance, oil resistance, and cold resistance, a copolymer rubber with 25-45% by weight of the unit
portion of unsaturated nitrile, 5% by weight or less of the unit portion of conjugated diene, and 5075% by weight of the unit portion of the hydrogenated unit portion of an ethylene unsaturated
monomer other than unsaturated nitrile and/or the unit portion of conjugated diene is preferred.
[0039] ZnO and MgO are both mixed into H-NBR as acid acceptors. For the reasons stated above,
the mixing amount of ZnO is preferably 2 phr or greater, and the mixing amount of MgO is 4 phr or
greater. More preferably, the upper limit for the mixing amount of ZnO is 10 phr, and the upper limit
for the mixing amount of MgO is 15 phr. In addition, the total mixing amount for ZnO and MgO is
preferably in the range of 6-15 phr.
[0040] With respect to heat resistance, H-NBR is peroxide vulcanized and except for the acid
acceptors described above, the types of vulcanization compounding ingredients are not restricted.
Preferably, organic peroxide vulcanization is conducted. Any organic peroxide can be selected and
used. For example, various monoperoxy compounds or diperoxy compounds can be used
individually or two or more types can be used together.
[0041] Monoperoxy compounds include dicumyl peroxide, diacyl peroxide (for example benzoyl
peroxide), di-t-butyl peroxide, t-butyl peroxide acetate, t-butyl peroxy isopropyl carbonate, peroxy
ester (for example, t-butyl peroxy benzoate), and the like. Diperoxy compounds include 2,5-dimethyl2,5-di-(t-butyl peroxy)-hexyne-3, 2,5-dimethyl-2,5-di-(t-butyl peroxy)-hexane, [alpha],[alpha]'-bis(tbutyl peroxy)-p-diisopropyl benzene, 2,5-dimethyl-2,5-di-(benzoyl peroxy)-hexane, and the like.
[0042] The mixing amount of the organic peroxide will depend on the type of the organic peroxide.
For example, when dicumyl peroxide is used by itself, approximately 0.5-8 phr is preferred. The
mechanical strength of H-NBR may be inadequate when the mixing amount of dicumyl peroxide is
less than 0.5 phr. If the mixing amount of dicumyl peroxide exceeds 8 phr, the non-vulcanized
molded body may be easily scorched.
[0043] Furthermore, silica fillers, age resistors, carbon black, plasticizers, co-crosslinking agents (for
example, TAIC and TMPTMA), and the like can be mixed with H-NBR, as needed.
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[0044] ACM
[0045] Acrylic rubber (ACM) used in the present invention is an epoxy cross-linking type of ACM.
"Acrylic rubber" is a general term encompassing acryl rubber and blend rubbers of this and other
types of rubber.
[0046] Examples of epoxy cross-linking type ACM include various monomer compositions formed by
copolymerization of any monomer selected from the following monomer group 1 through monomer
group 11 and any monomer selected from the following epoxy cross-linking monomer groups:
[0047] Monomer group 1: Methyl acrylate, ethyl acrylate, n-propyl acrylate, isobutyl acrylate, n-butyl
acrylate, n-pentyl acrylate, n-hexyl acrylate, n-octyl acrylate, or 2-ethyl hexyl acrylate.
[0048] Monomer group 2: Alkoxy alkyl acrylate group. For example, 2-methoxy ethyl acrylate, 2ethoxy ethyl acrylate, 2-(n-propoxy) ethyl acrylate, 2-(n-butoxy) ethyl acrylate, 3-methoxy propyl
acrylate, 3-ethoxy propyl acrylate, 2-(n-propoxy) propyl acrylate, or 2-(n-butoxy) propyl acrylate.
[0049] Monomer group 3: Fluorine containing acrylate group. For example, 1,1-dihydro perfluoro
ethyl (meta) acrylate, 1,1-dihydro perfluoro propyl (meta) acrylate, 1,1,5-trihydro perfluoro hexyl
(meta) acrylate, 1,1,2,2-tetrahydro perfluoro propyl (meta) acrylate, 1,1,7-trihydro perfluoro heptyl
(meta) acrylate, 1,1-dihydro perfluoro octyl (meta) acrylate, or 1,1-dihydro perfluoro decyl (meta)
acrylate.
[0050] Monomer group 4: Hydroxyl group containing acrylate group. For example, 1-hydroxy propyl
(meta) acrylate, 2-hydroxy propyl (meta) acrylate, or hydroxy ethyl (meta) acrylate.
[0051] Monomer group 5: Tertiary amino group containing acrylate group. For example, diethyl
amino ethyl (meta) acrylate or dibutyl amino ethyl (meta) acrylate.
[0052] Monomer group 6: Methacrylate group. For example, methyl methacrylate or octyl
methacrylate.
[0053] Monomer group 7: Alkyl vinyl ketone group. For example, methyl vinyl ketone.
[0054] Monomer group 8: Vinyl and allyl ether group. For example, vinyl ethyl ether or allyl methyl
ether.
[0055] Monomer group 9: Vinyl aromatic compound group. For example, styrene, [alpha]-methyl
styrene, chlorostyrene, or vinyl toluene.
[0056] Monomer group 10: Vinyl nitryl group. For example, acrylonitrile or methacrylonitrile.
[0057] Monomer group 11: Ethylene unsaturated compound group. For example, ethylene,
propylene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, vinyl propionate, or
alkyl fumarate.
[0058] Epoxy cross-linking monomer group: For example, glycidyl acrylate, allyl glycidyl ether, or
methaallyl glycidyl ether.
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[0059] A vulcanizing agent or vulcanization accelerator such as an ammonium salt is preferably
mixed into the ACM. When ammonium salt is used as a vulcanizing agent or vulcanization
accelerator, a compound or compound group as related to one of the following (1)-(3) or a
combination of two or more of any of (1)-(3) is preferable:
[0060] (1) ammonium benzoate;
[0061] (2) isocyanuric acid, quaternary ammonium salt, and diphenyl urea; and
[0062] (3) imidazole, thiourea, and quaternary ammonium salt.
[0063] The mixing amount of ammonium salt with respect to ACM is not restricted. However, the
mixing amount of ammonium salt is preferably approximately 0.1-3 phr. When the amount of
ammonium salt is below this range, there may be slightly reduced bonding with ACM. When the
amount of ammonium salt exceeds this range, the workability of the non-vulcanized molded body
may be reduced and the non-vulcanized molded body may become easily scorched.
[0064] In addition, small amounts of silica fillers can be mixed into ACM. Age resistors, carbon black,
plasticizers, processing aids (paraffin, for example), and the like are added, as needed.
[0065] Vulcanized-Bonded Layered Body and Hose
[0066] The uses for the vulcanized-bonded layered body constructed by the method of vulcanized
bonding of a heat resistant rubber as described above are not restricted. However, the layered body,
which has an inner layer of H-NBR and an outer layer of ACM, is preferably used as the inner pipe of
a hose. The inner pipe is the innermost layer of the hose.
[0067] The construction of the entire hose is not restricted provided the inner pipe of the hose is
constructed with the layered body as described above. For example, a reinforcement thread layer (or
reinforcement wire layer) of any substance, a rubber layer, a resin layer, and the like can be included
in any sequence on the outer perimeter of the rubber inner pipe. More preferably, a reinforcement
thread layer and a rubber outer pipe are provided sequentially on the outer perimeter of the rubber
inner pipe. The rubber outer pipe can be constructed by any type of rubber. However, examples of
the type of rubber used in the rubber outer pipe include ACM, acrylonitrile butadiene rubber (NBR),
blend material of NBR and polyvinyl chloride (NBR-PVC), ethylene propylene diene rubber (EPDM),
ethylene propylene rubber (EPM), chlorinated polyethylene rubber (CM), chlorosulfonated
polyethylene rubber (CSM), chloroprene rubber (CR), or blend rubber of two or more types selected
from these types of rubber.
[0068] There are no restrictions on the use of the hose having the vulcanized-bonded layered body
described above as the inner pipe of the hose. However, the hose is preferably used when heat
resistance and a secure bond between the H-NBR layer and the ACM layer are required. The hose is
also suitable when oil resistance and fuel resistance are required. Suitable examples of these types
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of hoses include a fuel hose, a oil hose, an air hose, or the like. Diesel fuel hoses and oil hoses are
especially preferred.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0069] Preparation of H-NBR Non-Vulcanized Compositions, NBR Non-Vulcanized Compositions,
and ACM Non-Vulcanized Compositions
[0070] Table 1 shows H-NBR non-vulcanized compositions and NBR non-vulcanized compositions,
which were prepared using an open roll, according to the proportions shown in columns A-F. Table 2
shows ACM non-vulcanized compositions, which were prepared using an open roll, according to the
proportions shown in columns 1-6. The numerical values in Tables 1 and 2 indicate the number of
parts by weight.
TABLE 1
ABCDEF
Zetpol 2000100100100100100Nipol DN202-----100
Zinc oxide5525-5
Magnesium oxide5102-55
FEF Carbon505050505050
Plasticizer202020202020
TAIC222222
Dicumyl peroxide444444
[0071]
TABLE2
123456
Nipol AR53100100100100100Vamac G-----100
Stearic acid111111
HAF Carbon606060606060
Plasticizer101010101010
Ammonium benzoate1.5----Isocyanuric acid-0.6---Quaternary ammonium salt-1.80.5--Diphenyl urea-1.3---Imidazole--0.50.5--
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Trimethyl thio urea--0.3--Hexamethylene diamine carbamate----1.51.5
Diortho tolyl guanidine----44
[0072] In Table 1, Zetpol 2000 is an H-NBR manufactured by Nippon Zeon Company, and Nipol
DN202 is an NBR manufactured by Nippon Zeon Company. In Table 2, Nipol AR53 is an epoxy
cross-linking type ACM manufactured by Nippon Zeon Company, and Vamac G is a carboxyl crosslinking type ACM manufactured by the DuPont Company.
[0073] Creation of a Vulcanized-Bonded Layered Body
[0074] The H-NBR non-vulcanized compositions or NBR non-vulcanized compositions mixed
according to columns A-F of Table 1 and the ACM non-vulcanized compositions mixed according to
columns 1-6 of Table 2 are each molded into a sheet which is 2 mm thick. Table 3 compares the
method for producing the layered bodies of Embodiments 1-4 and Comparative Examples 1-7.
Embodiments 1-4 and Comparative Examples 1-7 are prepared as shown in the "H-NBR or NBR"
column and the "Acrylic Rubber" column. The H-NBR non-vulcanized composition sheet or NBR nonvulcanized composition sheet is layered with the ACM non-vulcanized composition sheet in order to
construct the layered bodies of Embodiments 1-4 and Comparative Examples 1-7.
TABLE 3
MaterialPropertiesHeatCompression
ConstructionBondingResistanceSet of HH-NBRAcrylicStrengthSurfaceof LayeredNBR or NBR
or NBRRubber(N/25 mm)ConditionsBody%
Embodiment 1A270rubber-36damage
Embodiment 2B290 < (tear)rubber-29damage
Embodiment 3B160rubber-29damage
Embodiment 4B385rubber-29damage
Comparative ExampleC230surface-301peeling
Comparative ExampleD224surface-312peeling
Comparative ExampleE263rubber-72X
3damage
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Comparative ExampleF290 < (tear)rubberX100X
4damage
Comparative ExampleB429surface-295peeling
Comparative ExampleB510surface-296peeling
Comparative ExampleB612surface-297peeling
[0075] The division between "Embodiment" and "Comparative Example" in Table 3 is only used for
relative convenience. There are comparative examples shown in Table 3 that can be embodiments of
the present invention.
[0076] After conducting press vulcanization at 160[deg.] C. for 45 minutes on the layered bodies, hot
air vulcanization at 160[deg.] C. for 8 hours is conducted. As a result, the H-NBR sheet or NBR sheet
and the ACM sheet were vulcanized bonded.
[0077] Evaluation of the Vulcanized-Bonded Layered Body
[0078] Peeling Test
[0079] The vulcanized-bonded layered bodies of each of the embodiments and comparative
examples described above were subjected to a peeling test according to JIS K6256. The bonding
strength (N/25 mm) between the H-NBR sheet or NBR sheet and the ACM sheet and the surface
conditions of both sheets were evaluated. These results are shown in Table 3. In the "Bonding
Strength" column of Table 3, "90<(tear)" indicates that the sheet was torn while peeling and the
measurements at 90 N/25 mm or greater could not be measured. In the "Surface Conditions" column
of Table 3, "surface peeling" indicates that there was peeling along the interface of the sheets without
any damage to either sheet. Additionally, "rubber damage" indicates that there was damage to the
sheet, i.e., a portion of the material remained on top of the companion sheet, during peeling.
[0080] Heat Resistance
[0081] The vulcanized-bonded layered body of each of the above embodiments and comparative
examples were subjected to dry air aging at 150[deg.] C. for 500 hours. Then, each layered body
was folded back 180[deg.]. In the "Heat Resistance of Layered Body" column of Table 3, the layered
bodies that broke or had abnormalities, such as cracks or the like, are indicated by an "X", and the
layered bodies that did not have any abnormalities are indicated by an "O".
[0082] Compression Set of a Vulcanized H-NBR Test Piece and a Vulcanized NBR Test Piece
[0083] H-NBR non-vulcanized composition test pieces and NBR non-vulcanized composition test
pieces corresponding to each of the above embodiments and comparative examples were
vulcanized individually, i.e., without being affixed to ACM non-vulcanized composition test pieces.
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Press vulcanization at 160[deg.] C. for 45 minutes and hot air vulcanization of 160[deg.] C. for 8
hours were performed to each of the individual test pieces. The H-NBR non-vulcanized composition
test pieces and NBR non-vulcanized composition test pieces were then evaluated for compression
set under heat aging conditions of 150[deg.] C. for 240 hours according to JIS K6262. Test pieces
that had a compression set of less than 60% are indicated by an "O", and test pieces that had a
compression set of 60% or greater are indicated by an "X", as shown in the "Compression Set of HNBR or NBR" column of Table 3.
[0084] While the preferred embodiment has been described, variations thereto will occur to those
skilled in the art within the scope of the present inventive concepts which are delineated by the
following claims.Claims:
What is claimed is:
1. A method of vulcanized bonding a hydrogenated acrylonitrile butadiene rubber (H-NBR) and an
epoxy cross-linking type acrylic rubber (ACM), said method comprising:
mixing zinc oxide (ZnO), magnesium oxide (MgO), and H-NBR; and
peroxide vulcanizing said H-NBR at the same time as vulcanized bonding said ACM.
2. A method as described in claim 1, wherein said H-NBR is a hydrogenated or a partially
hydrogenated unsaturated nitrile-conjugated diene copolymer rubber.
3. A method as described in claim 1, wherein:
said H-NBR comprises:
an unsaturated nitrile, and
a conjugated diene,
a hydrogenating agent selected from the group consisting of an ethylene unsaturated monomer other
than unsaturated nitrile, conjugated diene, or a combination thereof.
4. A method as described in claim 3, wherein:
said H-NBR comprises:
25-45% by weight based upon the total weight of said H-NBR of said unsaturated nitrile;
5% by weight or less based upon the total weight of said H-NBR of said conjugated diene; and
50-75% by weight based upon the total weight of said H-NBR of said hydrogenating agent.
5. A method as described in claim 1, wherein:
the amount of said ZnO in said mixture of H-NBR is 2 phr or greater; and
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the amount of said MgO in said mixture of H-NBR is 4 phr or greater.
6. A method as described in claim 1, wherein:
said amount of said ZnO in said mixture of H-NBR is 2-10 phr; and
said amount of said MgO in said mixture of H-NBR is 4-15 phr.
7. A method as described in claim 1, wherein said peroxide vulcanization of said H-NBR is organic
peroxide vulcanization.
8. A method as described in claim 7, wherein an organic peroxide used in said organic peroxide
vulcanization comprises one or more members selected from the group consisting of a monoperoxy
compound and a diperoxy compound.
9. A method as described in claim 8, wherein said monoperoxy compound is selected from the
group consisting of dicumyl peroxide, diacyl peroxide, di-t-butyl peroxide, t-butyl peroxide acetate, tbutyl peroxy isopropyl carbonate, and peroxy ester.
10. A method as described in claim 8, wherein said diperoxy compound is selected from the group
consisting of 2,5-dimethyl-2,5-di-(t-butyl peroxy)-hexyne-3, 2,5-dimethyl-2,5-di-(t-butyl peroxy)hexane, [alpha],[alpha]'-bis(t-butyl peroxy)-p-diisopropyl benzene, and 2,5-dimethyl-2,5-di-(benzoyl
peroxy)-hexane.
11. A method as described in claim 8, wherein said organic peroxide used in said organic peroxide
vulcanization is dicumyl peroxide in an amount of 0.5-8 phr.
12. A method as described in claim 1, wherein said H-NBR is a mixture further comprising a member
selected from the group consisting of silica filler, age resistor, carbon black, plasticizer, cocrosslinking agent, or any combination thereof.
13. A method as described in claim 1, wherein said ACM is a mixture which further comprises an
ammonium salt.
14. A method as described in claim 13, wherein:
said ammonium salt is selected from the group consisting of:
(1) ammonium benzoate;
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(2) isocyanuric acid, quaternary ammonium salt, and diphenyl urea;
(3) imidazole, thiourea, and quaternary ammonium salt; and
(4) a combination of any of (1), (2), and (3).
15. A method as described in claim 13, wherein the amount of said ammonium salt is 0.1-3 phr.
16. A method as described in claim 1, wherein said ACM is a mixture which further comprises a
member selected from the group consisting of silica filler, age resistor, carbon black, plasticizer,
processing aid, and any combination of any of the foregoing.
17. A method as described in claim 1, wherein said H-NBR and said ACM are vulcanized bonded as
a flat or tube-shaped layered body to construct a flat or tube-shaped vulcanized-bonded layered
body.
18. A method as described in claim 1, wherein said H-NBR and said ACM are used as a layered
body in an inner pipe of a hose with said H-NBR in an inner layer of said layered body and said ACM
as an outer layer of said layered body.
19. A method as described in claim 18, wherein said hose is a fuel hose, an oil hose, or an air hose.
20. A method as described in claim 19, wherein said fuel hose is a diesel fuel hose.
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15. EP1375119 - 02.01.2004
METHOD FOR MANUFACTURING A SOLE FOR SHOES COMPOSED OF A TREAD SOLE THAT
COMPRISES VULCANIZED RUBBER COUPLED TO A POLYURETHANE MID-SOLE, AND
COMPOUND USED FOR THE METHOD
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=EP1375119
Inventor(s):
LORENZIN LORENZO [IT] (--)
Applicant(s):
MAIN GROUP SPA [IT] (--)
IP Class 4 Digits: B29D; A43B
IP Class:
B29D31/51; A43B13/04
E Class: A43B13/04; B29D31/51C2
Application Number:
EP20030013352 (20030616)
Priority Number: IT2002PD00174 (20020626)
Family: EP1375119
Equivalent:
CN1470201; ITPD20020174; US2004204546
Cited Document(s):
WO02052971; US4854841; US4858337; US3447251; DE3616874
Abstract:
THE METHOD IS CHARACTERIZED IN THAT THE MIX PROVIDED FOR THE VULCANIZABLE
RUBBER, COMBINED WITH AT LEAST ONE REINFORCING FILLER AND AT LEAST ONE
VULCANIZATION ACCELERATOR, COMPRISES A COMPOUND THAT CONTAINS AT LEAST ONE
NITRILE-BASED VULCANIZABLE RUBBER AND AT LEAST ONE ACRYLIC RESIN. A METERED
QUANTITY OF THE MIX IS INTRODUCED WITHIN A FIRST CAVITY OF A MOLD, WHOSE BOTTOM
IS CONSTITUTED BY A PISTON THAT IS KEPT AT A TEMPERATURE BETWEEN 100 AND 200 DEG
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C, WHILE IN AN UPPER REGION THERE IS A DUMMY LAST, WHICH IS ALSO KEPT AT A
TEMPERATURE BETWEEN 100 AND 200 DEG C, THE TWO TEMPERATURES BEING ADJUSTABLE
INDEPENDENTLY. ONCE THE TREAD SOLE HAS BEEN PREPARED IN THIS REGARD, THE SOLE
BOTTOM CARRIED BY THE PISTON DESCENDS, FORMING AN ADDITIONAL CAVITY INTO WHICH
THE POLYURETHANE IS INJECTION-MOLDED. THE VULCANIZED RUBBER CAN REACT FURTHER
WITH THE COMPONENTS OF THE POLYURETHANE, PRODUCING GREAT MUTUAL ADHESION OF
THE TWO MATERIALS. Description:
[0001] The present invention relates to a method for manufacturing a sole for shoes having a tread
sole that comprises vulcanized rubber coupled to a polyurethane mid-sole.
[0002] The present invention also relates to a particular mix used for the vulcanizable rubber that is
suitable to adhere to the polyurethane very safely.
[0003] The problems encountered in coupling vulcanized rubber and polyurethane are known from
the background art.
[0004] The two materials, at least the ones used up to now, are substantially mutually incompatible,
and in order to associate them, the vulcanized rubber must be cold-treated with a primer that makes
it ready to receive the poured or injection-molded polyurethane.
[0005] This entails, in the manufacture of soles for shoes or of entire shoes, the need to provide
tread soles made of vulcanized rubber that have a prepared surface and must then be placed inside
the molds where the polyurethane will be injection-molded or poured.
[0006] Instead of treatment with a primer, other solutions have been adopted, which provide for the
arrangement of a felt between the vulcanized rubber and the polyurethane, the felt having to be
compatible with both materials.
[0007] With these problems, it is evident that the vulcanized rubber tread sole cannot be prepared
in the same treatment cycle as the sole or shoe but must be prepared beforehand and separately,
allowed to cool and then subjected to a surface treatment, or it is necessary to use an auxiliary
component.
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[0008] The manufacture of shoes with vulcanized rubber tread sole and polyurethane mid-sole is
therefore scarcely convenient and excessively expensive.
[0009] On the other hand, the advantages of a sole with a vulcanized rubber tread sole and a
remaining part (mid-sole) made of polyurethane would be considerable, because a vulcanized
rubber tread sole is highly resistant to wear and thermal abrasion and a polyurethane mid-sole is
very light and comfortable.
[0010] The aim of the present invention is to provide a method that allows to provide, in a same
operating cycle, a sole that has a tread sole that comprises vulcanized rubber coupled to a
polyurethane mid-sole.
[0011] Within this aim, an object of the invention is to provide a method that does not require idle
times between the preparation of the tread sole comprising vulcanized rubber and the subsequent
coupling to a polyurethane mid-sole formed within a mold.
[0012] Another object is to provide a method in which it is not necessary to treat the tread sole
comprising vulcanized rubber before the injection-molding or pouring of the polyurethane into the
mold.
[0013] Another object is to provide products that can be suitable for performing the method.
[0014] This aim and these and other objects that will become better apparent hereinafter are
achieved by a method for manufacturing a sole for shoes that has a tread sole that comprises
vulcanized rubber coupled to a polyurethane mid-sole, said method consisting in:
a) preparing, for the vulcanizable rubber, a mix which, combined with at least one reinforcing filler
and at least one vulcanization accelerator, is characterized in that it comprises a compound that
contains:
a1) at least one nitrile-based vulcanizable rubber;
a2) at least one acrylic resin.
135/425
b) introducing a metered quantity of said mix within a first cavity of a mold, which is formed by a
pseudocylindrical side wall in which a sole bottom piston can move and is closed in an upper region
by a first replaceable dummy last;
c) waiting for a vulcanization time, while keeping the sole bottom piston at a temperature of 100200 DEG C and the dummy last at a temperature of 100-200 DEG C, said temperatures being
adjustable independently;
d) moving the sole bottom with the tread sole in contact therewith, so as to generate a second
cavity, and replacing the dummy last with a second dummy last or with a last with a fitted upper,
closing it with the rings;
e) injecting or pouring into said second cavity a metered quantity of polyurethane;
f) waiting for the reaction time of the polyurethane, keeping the second dummy last and the rings at
a temperature lower than 120 DEG C;
g) removing the sole and allowing it to rest for the stabilization time.
[0015] Advantageously, by keeping the rubber at 100-110 DEG C, for example by means of air
jets provided with known means, before the injection or pouring of the polyurethane, the mutual
bonding of the materials is facilitated.
[0016] The present invention also relates to the use of a vulcanizable rubber that is obtained with a
mix which, combined with at least one reinforcing filler and at least one vulcanization accelerator, is
characterized in that it comprises a compound that contains at least one vulcanizable nitrile-based
rubber and at least one acrylic resin, in order to form a sole for shoes that is composed of a tread
sole that comprises vulcanized rubber coupled to a polyurethane mid-sole.
[0017] Further characteristics and advantages of the invention will become better apparent from
the following detailed description of a preferred embodiment of the method, illustrated also with the
aid of the accompanying drawings, wherein:
Figure 1 is a schematic sectional view of the mold used;
Figure 2 is a more detailed, partly sectional, view of the structure of the mold and of its movement
means, with the mold in the open position;
Figure 3 is a view of the assembly of Figure 2, with the mold closed in order to form the tread sole
comprising vulcanized rubber;
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Figure 4 is a view of the mold and of its closure means in the step of the method related to the
injection of the polyurethane.
[0018] The method according to the invention provides for a first step in which a vulcanizable
rubber is prepared which is obtained with a mix which, combined with at least one reinforcing filler
and at least one vulcanization accelerator, is characterized in that it comprises a compounds that
contains:
a1) at least one vulcanizable nitrile-based rubber;
a2) at least one acrylic resin.
[0019] The nitrile-based rubber that is used is conveniently of the medium-high nitrile type
(substantially 30-38% nitrile in the polymer) with a low Mooney value (indicatively, a viscosity of 40-42
Mooney).
[0020] A rubber of this kind comprises for example a butadiene-acrylonitrile copolymer technically
referenced as NBR.
[0021] The acrylic resin is hydroxylated, preferably with a hydroxyl lower than 2 in naphtha as
solvent.
[0022] This resin is preferably used in a solvent and its percentage by weight does not exceed 6%
of the overall weight of the mix.
[0023] A reinforcing filler of the siliceous type is also added to the mix in a per se known manner.
[0024] Said reinforcing filler is preferably precipitated amorphous silica or is a composition that
contains 85 to 90% SiO2 with a BET from 150 to 200 m/g.
[0025] The reinforcing filler is present in a percentage by weight that is between 20 and 25% of the
overall weight of the mix.
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[0026] The vulcanization accelerator is for example of the mercaptan class, with the addition of an
ultra-accelerator.
[0027] The accelerator is introduced in the mix in a per se known manner in a percentage by
weight that is between 1 and 1.5% of the overall weight of the mix.
[0028] While continuing the description of the method, it is convenient to describe also the
structure of the mold that is used, and this is done with reference to the accompanying drawings.
[0029] With reference to the drawings, Figure 1 illustrates schematically the mold that is used in the
method according to the present invention.
[0030] The mold is composed of a carriage plate 1, on which the part 2 of a mold that will form the
sole bottom or tread sole 17 of the vulcanized rubber sole is fixed.
[0031] The part 2 of the mold is fixed to the carriage plate 1 with the interposition of a heating plate
3.
[0032] A pivoted coupling arm 4 for rotating the last is visible in an upper region.
[0033] In the lower part of said arm there is an insulating plate 5, which with the interposition of a
heating plate 6 supports a dummy last 7, which has a first cavity 8 that corresponds to the upper part
of the tread sole that comprises vulcanized rubber.
[0034] Figure 1 again illustrates ring holders 9 and rings 10 of the mold that act on the dummy last
7 with the interposition of insulating means 11.
[0035] The combination of the heating plates and of the insulating means allows to adjust
independently the upper and lower temperatures of the mold.
[0036] Figures 2, 3 and 4 show in greater detail the structure of the mold and its fixtures.
[0037] Figure 2 illustrates the assembly in the condition in which the mold is open, the mold being
the one designed to produce the tread sole and being formed with a pseudocylindrical side wall 15
in which a sole bottom piston 12 may move.
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[0038] This figure clearly shows the presence of the piston 12 that allows to move the lower part 2
of the mold.
[0039] Figure 3 is a view of the same assembly of Figure 2 in the condition in which the mold is
closed, when a tread sole, designated by the reference numeral 13, is formed.
[0040] In Figure 4, the dummy last 7 is replaced with a second dummy last or a last with a fitted
upper 13 and the same figure also illustrates the step for injecting and molding a polyurethane midsole 14 in a second cavity 16 formed by moving the sole bottom piston 12 with the tread sole 17 in
contact therewith.
[0041] As can be noted, the preparation of the tread sole comprising vulcanized rubber and the
subsequent operation for coupling with the polyurethane mid-sole occur in the same machine and
with an operating cycle in which the two steps occur one after the other.
[0042] As regards the reasons for the coupling between the vulcanized rubber and the
polyurethane, they reside in the use of a compound that contains acrylic resin.
[0043] Said resin, at the end of the vulcanization step on the part of the sole where the
polyurethane will be deposited, can react with the components of the polyurethane, producing an
intimate and strong coupling.
[0044] It is important to leave the parts of the mold not perfectly or completely closed, so that, what
is known as engineered flash, is formed.
[0045] This allows the optimum manufacture of the tread sole comprising vulcanized rubber and of
the polyurethane mid-sole.
[0046] From what has been described and illustrated, it can be noted that the proposed aim and
objects have all been achieved and in particular that a method has been devised which allows to
provide a tread sole that comprises vulcanized rubber coupled to a polyurethane mid-sole, and that
the entire operation occurs with a succession of steps that can be performed in a single machine
and sequentially.
139/425
[0047] Equivalent components and equivalent mold structures can of course be used starting from
the same inventive concept as defined in the appended claims.
[0048] The disclosures in Italian Patent Application No. PD2002A000174 from which this
application claims priority are incorporated herein by reference.
[0049] Where technical features mentioned in any claim are followed by reference signs, those
reference signs have been included for the sole purpose of increasing the intelligibility of the claims
and accordingly, such reference signs do not have any limiting effect on the interpretation of each
element identified by way of example by such reference signs.Claims:
1. A method for manufacturing a sole for shoes having a tread sole that comprises vulcanized rubber
coupled to a polyurethane mid-sole, said method consisting in:
a) preparing, for the vulcanizable rubber, a mix which, combined with at least one reinforcing filler
and at least one vulcanization accelerator, is characterized in that it comprises a compound that
contains:
a1) at least one nitrile-based vulcanizable rubber;
a2) at least one acrylic resin.
b) introducing a metered quantity of said mix within a first cavity (8) of a mold (2), which is formed
by a pseudocylindrical side wall (15) in which a sole bottom piston (12) can move and is closed in an
upper region by a first replaceable dummy last (7);
c) waiting for a vulcanization time, while keeping the sole bottom piston (12) at a temperature of
100-200 DEG C and the dummy last (7) at a temperature of 100-200 DEG C, said temperatures
being adjustable independently;
d) moving the sole bottom piston (12) with the tread sole (17) in contact therewith, so as to
generate a second cavity (16), and replacing the dummy last (7) with a second dummy last or a last
(13) with a fitted upper, closing it with the mold rings (10);
e) injecting or pouring into said second cavity (16) a metered quantity of polyurethane;
f) waiting for the reaction time of the polyurethane, keeping the second dummy last (13) and the
rings (10) at a temperature lower than 120 DEG C;
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g) removing the sole and allowing it to rest for the stabilization time.
2. The method according to claim 1, characterized in that the rubber is kept at 100-110 DEG C
before injecting or pouring the polyurethane.
3. The method according to claim 2, characterized in that it keeps the rubber at 100-110 DEG C by
means of air jets.
4. The method according to claim 1, characterized in that said nitrile rubber is of the medium-high
nitrile type.
5. The method according to claims 1 and 4, characterized in that said nitrile rubber preferably has a
low Mooney value (low viscosity).
6. The method according to claim 4, characterized in that said nitrile rubber comprises a butadieneacrylonitrile copolymer commonly known as NBR.
7. The method according to claim 1, characterized in that said acrylic resin is hydroxylated.
8. The method according to claim 7, characterized in that the hydroxyl is less than 2.
9. The method according to claims 7 and 8, characterized in that said resin is provided in a naphtha
solvent.
10. The method according to claim 1, characterized in that said acrylic resin is present in a
percentage by weight of no more than 6% of the overall weight of the mix.
11. The use of a vulcanizable rubber obtained with a mix which, combined with at least one
reinforcing filler and at least one vulcanization accelerator, is characterized in that it comprises a
compound that contains at least one vulcanizable nitrile-based rubber and at least one acrylic resin
for providing a sole for shoes that is composed of a tread sole that comprises vulcanized rubber
coupled to a polyurethane mid-sole.
141/425
12. The use of a rubber according to claim 11, characterized in that it employs a vulcanizable nitrile
rubber (NBR) of the medium-high nitrile type.
13. The use of a rubber according to claim 11, characterized in that it uses, as a nitrile rubber, a
butadiene-acrylonitrile copolymer commonly known as NBR.
14. The use of a rubber according to claim 11, characterized in that said acrylic resin is hydroxylated.
15. The use of a rubber according to claim 14, characterized in that the hydroxyl is less than 2.
16. The use of a rubber according to claims 14 and 15, characterized in that said resin is provided in
a naphtha solvent.
142/425
16. ES2211247 - 01.07.2004
PROCEDURE IS FOR MANUFACTURING ARTICLES OF MOLDED VULCANIZED RUBBER OF LOW
DENSITY, PARTICULARLY FOR CONSTRUCTING FLOORS
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=ES2211247
Inventor(s):
CASADO BERGARA FERNANDO [ES] (--)
Applicant(s):
AITA CONSULTORES DE INNOVACION [ES] (--)
IP Class 4 Digits: B29C
IP Class:
B29C39/00
Application Number:
ES20010001162 (20010522)
Priority Number: ES20010001162 (20010522)
Family: ES2211247
Abstract:
THE PROCEDURE IS FOR MANUFACTURING ARTICLES OF MOLDED VULCANIZED RUBBER OF
LOW DENSITY, PARTICULARLY FOR CONSTRUCTING FLOORS. A MIXTURE OF RAW RUBBER
AND AT LEAST ONE VULCANIZATION AGENT IS PLACED IN A PRE-HEATED MOLD, THE
COMPONENTS THEMSELVES HAVING BEEN PRE-HEATED AND PLASTIFIED. TIME IS THEN
ALLOWED FOR THE VULCANIZATION REACTION TO OCCUR AFTER WHICH THE MOLD IS
OPENED AND THE MOLDED ARTICLE IS REMOVED.
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17. JP2002241541 - 10.10.2002
TERPOLYMER-CONTAINING RUBBER MIXTURES
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2002241541
Inventor(s):
ENGEHAUSEN RUDIGER [DE] (--); RAWLINSON ADRIAN [DE] (--); WENDLING
PETER [DE] (--)
IP Class 4 Digits: C08J
IP Class:
C8J3/00
E Class: C08L21/00+B2B; C08K5/00P1+L9/06; C08L9/06+B2B
Application Number:
US20020056862 (20020125)
Priority Number: DE20011004236 (20010131)
Family: JP2002241541
Equivalent:
BR0200249; CA2369421; CZ20020362; DE10104236; EP1229072; HU0200340;
MXPA02001067; SK1482002
Abstract:
THE PRESENT INVENTION PROVIDES RUBBER MIXTURES WHICH CONTAIN AT LEAST ONE NSBR
TERPOLYMER AND AT LEAST ONE POLAR SYNTHETIC PLASTICIZER, A PROCESS FOR THE
PREPARATION THEREOF AND THEIR USE TO PRODUCE RUBBER MOLDED ITEMS OF ALL
KINDS.Description:
FIELD OF THE INVENTION
[0001] The invention provides rubber mixtures which contain terpolymers based on an unsaturated
olefinic nitrile, a vinylaromatic compound and a conjugated diene and also at least one polar
synthetic plasticizer. Rubber mixtures according to the present invention may be used to prepare
rubber molded items, in particular tires.
144/425
[0002] It is known that resistance to wet-skidding and abrasive strength can be improved by using
terpolymers based on a conjugated diolefin, a vinylaromatic compound and an olefinically
unsaturated nitrile. In this connection, reference is made, for example, to EP-A 537 640, U.S. Pat. Nos.
5,310,815, 5,225,479, DE-A 3 837 047 and EP-A 0 736 399. In addition, it is mentioned in these
patents that the terpolymers disclosed therein may be admixed with other rubbers, wherein
conventional rubber auxiliary substances may be added to these mixtures. Included among the very
wide variety of rubber auxiliary substances, plasticizers are also described as auxiliary substances
that may be used in a conventional manner.
BACKGROUND OF THE INVENTION
[0003] The terpolymers and their mixtures with other rubbers described in the patents mentioned,
however, still require some improvement with regard to dynamic properties such as the dynamic
modulus at low temperatures and combination of the properties resistance to rolling, resistance to
wet-skidding and abrasion.
[0004] It is know that carbon black or silica-containing tire treads based on non-polar rubbers or
mixtures of the same which contain NSBR lead to an considerable increase in the tan [delta] value at
0[deg.] C., which indicates improved resistance to wet-skidding. Improved resistance to abrasion is
also found, depending on the particular rubber mixture used. However, the use of NSBR in such
mixtures also has negative effects, such as a greatly increased dynamic modulus at 0[deg.] C. and
an elevated tan [delta] value at 60[deg.] C. A tire tread mixture with a high dynamic modulus at
0[deg.] C., however, has disadvantages at low temperatures with respect to ABS braking
characteristics in the wet and also the driving characteristics. A high tan [delta] value at 60[deg.] C.
also indicates a higher rolling resistance.
SUMMARY OF THE INVENTION
[0005] Now, the object of the present invention is to provide rubber mixtures, based on terpolymers
of the composition mentioned above, which have improved dynamic properties, such as the dynamic
modulus at low temperatures, and also an improved combination of the properties rolling resistance,
wet-skidding characteristics and resistance to abrasion.
[0006] This object is achieved by adding polar synthetic plasticizers to rubber mixtures which
contain the terpolymers.
[0007] Therefore, the present invention provides rubber mixtures that contain
[0008] a) at least one terpolymer (NSBR) comprising an olefinically unsaturated nitrile, a
vinylaromatic compound and a conjugated diene and
[0009] b) at least one polar synthetic plasticizer,
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[0010] wherein component b) is present in amounts of 0.5 to 50 wt. %, with respect to the amount of
terpolymer (a).
DETAILED DESCRIPTION OF THE INVENTION
[0011] Rubber mixtures in which component b) is present in amounts of 5 to 40 wt. %, in particular
10 to 30 wt. %, each with respect to the amount of terpolymer (a), are preferred.
[0012] The terpolymer used as component a) in rubber mixtures according to the present invention is
based, as mentioned above, on unsaturated olefinic nitrites, vinylaromatic compounds and
conjugated dienes.
[0013] Suitable conjugated dienes are, in particular: 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2methyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3hexadiene, 2-phenyl-1,3-butadiene, 3,4-dimethyl-1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene, 4,5diethyl-1,3-octadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene or mixtures of the dienes
mentioned. The following are preferably used as conjugated dienes: 1,3-butadiene and 2-methyl-1,3butadiene, in particular 1,3-butadiene.
[0014] Vinylaromatic compounds which may be mentioned are those which contain 8 to 16 carbon
atoms in the molecule such as styrene, [alpha]-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4methylstyrene, 4-cyclohexylstyrene, 4-p-toluenestyrene, p-chlorostyrene, p-bromostyrene, 4-tertbutylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene or mixtures of the same, wherein styrene is
preferred.
[0015] Olefinically unsaturated nitrites, which may be used to build up the terpolymer are acrylonitrile,
methacrylonitrile, ethylacrylonitrile, crotononitrile, 2-pentenonitrile or mixtures of the same, wherein
acrylonitrile is preferred.
[0016] Terpolymers to be used according to the present invention contain the conjugated dienes in
amounts of about 40 to 89 wt. %, the vinylaromatic compounds in amounts of about 10 to 40 wt. %
and the olefinically unsaturated nitrites in amounts of about 1 to 50 wt. %, wherein the amounts of the
individual components add up to 100 wt. %.
[0017] The conjugated dienes are preferably used in amounts of 40 to 80 wt. %, the vinylaromatic
compounds in amounts of 10 to 35 wt. % and the olefinically unsaturated nitrites in amounts of 10 to
40 wt. %.
[0018] Depending on the amounts of the structural components being used, the glass transition
temperature of terpolymers used according to the present invention is about -60 to 0[deg.] C.,
preferably -45 to -15[deg.] C.
[0019] NSBR terpolymers used according to the present invention are known, for example from the
patent documents mentioned above, as well as the method of preparation.
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[0020] As mentioned above, it is of particular importance for the physical properties of rubber
mixtures according to the present invention, and the vulcanizates and molded items produced
therefrom, that polar synthetic plasticizers are added to the rubber mixtures. Suitable polar synthetic
plasticizers are those which contain e.g. ester or ether groups in the molecule, for example
phthalates such as dibutyl phthalate (DBP), dioctyl phthalate (DOP), diisononyl phthalate (DINP),
diisodecyl phthalate (DIDP), diisotridecyl phthalate (DTDP), diundecyl phthalate (DUP), sebacates
such as dioctyl sebacate (DOS), dibutyl sebacate (DBS), adipates such as dioctyl adipate (DOA),
diisodecyl adipate (DIDA), diisononyl adipate (DINA), di-(butoxyethoxyethyl) adipate, phosphates
such as tricresyl phosphate (TCP), trixylyl phosphate (TXP), trioctyl phosphate (TOP), diphenylcresyl
phosphate, diphenyloctyl phosphate, trichloroethyl phosphates, stearates such as butyl stearate,
azelates such as dioctyl azelate, oleates such as dibutyl oleate, trimellitates such as trioctyl mellitate,
tri-linear-C7-C9 trimellitates, glycolates such as dibutylmethylene-bis-thioglycolate, di-2-ethylhexylthiodigycolate ester, nylonates such as dioctyl nylonate, diisodecyl nylonate, phenylalkyl sulfonates,
butyl-carbitol-formal, and mixed esters of adipic, glutaric and succinic acids.
[0021] In addition, suitable polar plasticizers are: chlorinated paraffins with a chlorine content of 40 to
70 wt. % and also plasticizers based on epoxy esters, based on polyesters and polyethers, based on
ether-thioethers and also those based on phenolsulfonates.
[0022] The polar synthetic plasticizers may be used either separately or as a mixture with each other.
The most beneficial mixture is governed by the particular ultimate purpose of the rubber mixtures
according to the present invention.
[0023] Plasticizers based on phthalic acid, sebacic acid and adipic acid, of the type mentioned
above, are preferred.
[0024] Obviously, rubber mixtures according to the present invention may contain, in addition to the
polar synthetic plasticizers, known fillers and rubber auxiliary substances such as pigments, zinc
oxide, stearic acid, vulcanization accelerators, vulcanization agents, for example, those based on
sulfur and peroxide, stabilizers, antioxidants, resins, oils, waxes and inhibitors.
[0025] Suitable fillers for rubber mixtures according to the present invention are either the well-known
carbon blacks and silicas, or else silicates, titanium dioxide, chalk or clay or mixtures of the same.
Carbon black and silica are preferably used as fillers.
[0026] When using silicas in the rubber mixtures, so-called filler activators such as bis-3(triethoxysilylpropyl) tetrasulfite, may also be used in a well-known manner.
[0027] The additives and auxiliary substances mentioned are also known to a person skilled in the art
and are described, inter alia, in Kautschuk-Technology by Werner Hoffmann, post-doctoral thesis for
the faculty of engineering, T H Aachen, 1975; Handbuch fьr die Gummiindustrie from Bayer A G,
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Leverkusen, Hoffmann, W.: Kautschuktechnology Stuttgart (Genter 1980) and in Helle Fьllstoffe in
Polymeren, Gummi Faser Kunststoffe 42 (1989) no. 11.
[0028] The fillers and rubber auxiliary substances mentioned are used in conventional amounts. The
most beneficial amounts in any particular instance are governed, inter alia, by the intended ultimate
purpose of the rubber mixtures and may be readily determined by appropriate preliminary trials.
[0029] Obviously, natural (NR) and synthetic rubbers may also be added to rubber mixtures
according to the present invention, such as, for example, polybutadiene (BR), styrene/butadiene
copolymers (SBR), polyisoprene rubbers (IR), isoprene/butadiene rubbers,
isoprene/butadiene/styrene rubbers, ethylene/propylene rubbers. Polybutadiene, styrene/butadiene
copolymers and natural rubbers are preferably used. Oils based on aromatic compounds,
naphthenes or paraffins may obviously also be added to the additional rubbers mentioned for use in
rubber mixtures according to the present invention, as is conventional.
[0030] The additionally used rubbers are prepared in a conventional manner by radical emulsion
polymerization, radical solution polymerization, anionic or cationic polymerization or by Ziegler-Natta
polymerization in a well-known manner.
[0031] The amount of added additional rubber may vary over a wide range and is governed in
particular by the subsequent intended purpose of rubber mixtures according to the present invention
based on NSBR and synthetic plasticizers.
[0032] In general, the additional rubbers mentioned are used in amounts of 1 to 99, preferably 10 to
90, more preferably 20 to 80 wt. %, with respect to the entire amount of rubber.
[0033] Rubber mixtures according to the present invention may be prepared by intensive mixing of
the individual components with each other in suitable mixing units such as rollers or compounders.
[0034] Rubber mixtures according to the present invention are preferably prepared by mixing
component a), i.e. the terpolymer (NSBR) in latex form with the polar synthetic plasticizer(s)
(component b)) and working up the mixture obtained thereby in an appropriate manner by
coagulating and then drying.
[0035] Addition of the plasticizer to the NSBR latex may be performed by simple mixing of the two
components. It is also possible to add the plasticizer in the form of an aqueous emulsion to the latex,
wherein conventional, known emulsifiers are added. It is then possible to use those emulsifiers which
were also used during preparation of the latex. Obviously, the use of other emulsifiers is also
possible.
[0036] The NSBR latex/plasticizer mixture may be prepared at room temperature or at elevated
temperature, the latter in particular when the plasticizer being added has a high viscosity.
[0037] Coagulation of the latex/plasticizer mixture may be performed by known and conventional
methods. Examples of these are the introduction of mechanical energy, wherein coagulation is
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achieved by shearing, the use of a purely thermal process or by the addition of precipitating agents
such as alkali metal, alkaline earth metal or aluminium salts or inorganic or organic acids, wherein the
use of precipitation auxiliary agents such as gelatine and/or polyelectrolytes is also possible. The use
of precipitating agents of the type mentioned is preferred.
[0038] The coagulated mixture may be subjected to one or more wash steps, in a known manner,
wherein preliminary dewatering in equipment suitable for this purpose, for example in a dewatering
screw, is possible before drying the coagulated mixture.
[0039] The fillers and rubber auxiliary substances described above may then be admixed with the
coagulated and dried rubber mixtures obtained, in a known manner.
[0040] Rubber mixtures according to the present invention may be vulcanized in a conventional way,
wherein the most expedient vulcanization process to use is governed by the particular ultimate
purpose of the rubber mixtures.
[0041] Rubber mixtures according to the present invention may be used to produce vulcanizates of
all kinds, in particular to produce tire components and to produce industrial rubber goods such as
belts, seals and hoses.
[0042] Use of rubber mixtures according to the present invention in tire structures, in particular for
tire treads, is preferred.
[0043] In the following examples, the properties of rubber mixtures according to the present
invention of comparison rubber mixtures and of the resulting vulcanizates were measured as follows:
[0044] (1) The polymer composition was measured by means of IR spectroscopy.
[0045] (2) The Mooney viscosity of the rubber was determined according to DIN 53523.
[0046] (3) The tensile strength of the vulcanizates was determined according to DIN 53504.
[0047] (4) The extension at break of the vulcanizates was determined according to DIN 53504.
[0048] (5) The modulus of the vulcanizates at 100 and 300% extension was determined according to
DIN 53504.
[0049] (6) The hardness of the vulcanizates at 70[deg.] C. was determined according to DIN 53505.
[0050] (7) Abrasion of the vulcanizates was determined according to DIN 53516.
[0051] (8) Tan [delta] of the vulcanizates was determined according to DIN 53513.
EXAMPLES
[0052] The following components were used for comparison rubber mixtures 1 and 2 and also for
rubber mixtures 1, 2 and 3 according to the present invention:
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[0053] NSBR (rubber prepared by emulsion polymerization, 58.5% butadiene, 20.3% styrene and
21.1% acrylonitrile, Mooney viscosity 49), Krylene(R) 1500 (emulsion SBR, 23.5% styrene,
manufacturer Bayer Elastomers),
[0054] NR (natural rubber TSR 5, cis-1,3-polyisoprene),
[0055] Renopal(R) 450 (aromatic mineral oil/plasticizer, manufacturer Fuchs Chemie),
[0056] Corax(R) N339 (carbon black, manufacturer Degussa Hьls AG),
[0057] Stearic acid,
[0058] ZnO (zinc oxide),
[0059] Sulfur,
[0060] Vulkanox(R) 4010 (N-isopropyl-N'-phenyl-p-diphenylenediamine, manufacturer Bayer AG),
[0061] Vulkanox(R) 4020 (N-(1,3-dimethylbutyl)-N'phenyl-p-phenylenediamine, manufacturer Bayer
AG),
[0062] Vulkacit(R) D (diphenylguanidine, manufacturer Bayer AG),
[0063] Vulkacit(R) CZ/C (N-cyclohexyl-2-benzothiazyl-sulfenamide, manufacturer Bayer AG),
[0064] DOP: Vestinol AH, (dioctyl phthalate, Hьls AG),
[0065] DOS: Edenol 888, (dioctyl sebacate, Henkel KGaA),
[0066] The individual proportions by weight of the components are listed in Tables 1 and 2.
[0067] The components were mixed in a compounder (Werner & Pfleiderer GK 1.5) at 50 rpm. The
compounding temperature was 60[deg.] C. The vulcanization accelerator was admixed on a roller.
[0068] The results of the tests are given in Tables 1 and 2.
TABLE 1
Example 1Example 2Comp. Example 1
Krylene (R) 1500808080
NSBR 20% ACN202020
Corax (R) N339505050
Aromatic oil151530
DOP1500
DOS0150
Stearic acid222
Zinc oxide333
Vulkanox (R) 4010111
Vulkanox (R) 4020111
Sulfur222
Vulkacit (R) CZ/C1.51.51.5
Vulkacit (R) D0.20.20.2
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Tensile strength (MPa)21.120.621.1
Extension at break (%)635625640
Modulus 100% (MPa)1.51.51.6
Modulus 300% (MPa)6.66.76.5
Hardness 23[deg.] C. (Shore A)575557
Hardness 70[deg.] C. (Shore A)515151
DIN abrasion 60 (mm)130115140
tan [delta] 0[deg.] C.0.4770.4960.463
23[deg.] C.0.2780.2730.339
60[deg.] C.0.1930.1870.216
E* 0[deg.] C.19.48916.72362.777
23[deg.] C.8.5737.37610.555
60[deg.] C.5.4245.4385.727
E' 0[deg.] C.17.58914.98356.973
23[deg.] C.8.2617.1159.995
60[deg.] C.5.3265.3465.598
E'' 0[deg.] C.8.3947.42926.365
23[deg.] C.2.2941.9453.391
60[deg.] C.1.02511.209
[0069] The results in Table 1 show that rubber mixtures according to invention exhibit advantages
over those from the prior art in properties such as much lower dynamic moduli, higher tan [delta]
values at 0[deg.] C. (better resistance to wet-skidding), lower tan [delta] values at 60[deg.] C. (lower
resistance to rolling) and lower DIN abrasion (less wear), while they have comparable mechanical
properties.
TABLE 2
Example 3Comp. example 2
NR (masticated)8080
NSBR 20% ACN2020
Corax (R) N3395050
Aromatic oil1530
DOP150
Stearic acid22
Zinc oxide33
Vulkanox (R) 401011
Vulkanox (R) 402011
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Sulfur22
Vulkacit (R) CZ/C1.51.5
Vulkacit (R) D0.20.2
Tensile strength (MPa)23.823.5
Extension at break (%)615610
Modulus 100% (MPa)1.81.8
Modulus 300% (MPa)7.77.1
Hardness 23[deg.] C. (Shore A)5959
Hardness 70[deg.] C. (Shore A)5151
DIN abrasion 60 (mm)130130
tan [delta] 0[deg.] C.0.4240.452
23[deg.] C.0.2430.3
60[deg.] C.0.1550.178
E* 0[deg.] C.13.03937.024
23[deg.] C.6.7777.847
60[deg.] C.4.8084.911
E' 0[deg.] C.12.00633.738
23[deg.] C.6.5867.515
60[deg.] C.4.7514.835
E'' 0[deg.] C.5.08815.248
23[deg.] C.1.5992.257
60[deg.] C.0.7380.86
[0070] The results in table 2 show that rubber mixtures according to the present invention exhibit
advantages over those from the prior art in properties such as much lower dynamic moduli and lower
tan [delta] values at 60[deg.] C. (lower resistance to rolling) while they have comparable mechanical
properties.
Example 4
[0071] (Preparing Rubber Mixtures According to the Present Invention by the Latex Process)
[0072] Preparing the Terpolymers
[0073] 3] 1631.3 g styrene, 7.31 g tert.-dodecylmercaptan, 900 g acrylonitrile and a solution
consisting of 7537.4 g fully deionised water, 197.68 g disproportionated resin acid (sodium salt, 70%
strength), 2175 g partially hydrogenated tallow fatty acid (potassium salt, 9% strength), 14.06 g
potassium hydroxide (85% strength), 32.06 g condensed naphthalenesulfonic acid (Na salt) and
14.63 g potassium chloride were initially introduced into an evacuated stirrable 20 I steel reactor. All
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the components had previously been flushed out with nitrogen. Then 4162.50 g butadiene were
added and the emulsion was brought to a constant temperature of 10[deg.] C. with stirring.
Polymerization was initiated by adding 1.52 g p-menthane hydroperoxide (50% strength) and a
solution consisting of 167.91 g fully deionised water, 1.69 g EDTA, 1.35 g iron(II) sulfate
heptahydrate, 3.46 g sodium formaldehydesulfoxylate and 5.23 g sodium phosphate dodecahydrate
and allowed to proceed with stirring at 10[deg.] C. lsqb;0073]
[0074] Polymerization was terminated at a conversion of 80.2% by adding 22.5 g
diethylhydroxylamine (25% strength) and 1.13 g sodium dithionite. 13.50 g Vulkanox(R) BKF (2,2'methylene-bis-(4-methyl-6-tert.-butylphenol), product from Bayer AG, Leverkusen), added in the form
of a 46% strength dispersion (29.35 g), were added to the latex. Unreacted butadiene was degassed
and unreacted monomers were removed from the latex with steam. A small sample was coagulated
and the polymer was dried. The polymer had a Mooney viscosity (ML 1+4) of 151. The polymer
composition was determined by IR spectroscopy, giving 57.4% butadiene, 22.7% styrene and 19.9%
acrylonitrile. The gel content in toluene was 2.2%.
[0075] Preparing the Latex-plasticizer Mixture
[0076] 275 g DOP (25 phr) were added to 3200 g latex, corresponding to 1100 g polymer. For this
purpose, the DOP was emulsified in an aqueous solution consisting of 340.93 g water, 0.41 g
polynaphthalenesulfonic acid, 59.4 g disproportionated resin acid (sodium salt, 10% strength) and
11.62 g partially hydrogenated tallow fatty acid (potassium salt, 9% strength) with stirring. The latex
and DOP emulsion were heated to 60[deg.] C. and mixed with stirring. Stirring was continued for 30
min.
[0077] Coagulating the Latex-plasticizer Mixture
[0078] 10 kg of fully deionised water, heated to 65[deg.] C., 825 g sodium chloride and 2.25 g
polyamine (Superfloc(R) C567) were initially introduced into a stirred tank. The latex-plasticizer
mixture was added at 65[deg.] C. with stirring. The pH of the precipitation serum was adjusted to
and maintained at 4 by adding 10% strength sulfuric acid.
[0079] The precipitation serum was clear. The DOP-extended rubber was filtered off and washed
with fully deionised water, heated to 65[deg.]C., for 15 min with stirring. The water: rubber ratio was
10:1. The moist, DOP-extended rubber was dried at 70[deg.] C. in a vacuum drying cabinet. The
Mooney viscosity (ML 1+4) was 66 MU.
[0080] Examples 5 to 7 were prepared in the same way. Table 3 gives a summary of the
masterbatches prepared according to the present invention.
TABLE 3
PlasticizerExample 4Example 5Example 6Example 7
DOP25 phr
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DOP50 phr
DOS37.5 phr
TKP 37.5 phr
ML 1 + 4 of the663447 100
master batches
[0081] Testing Examples and Comparison Examples
[0082] The following components were used for the comparison rubber mixtures and rubber mixtures
according to the present invention. Masterbatches from examples 6 to 9
[0083] NSBR (rubber prepared by emulsion polymerization, 58.5% butadiene, 20.3% styrene and
21.1% acrylonitrile, Mooney viscosity 49),
[0084] SBR 1500 (Krylene(R) 1500, emulsion SBR, 23.5% styrene, manufacturer Bayer Elastomers),
[0085] Renopal(R) 450 (aromatic mineral oil/plasticizer, manufacturer Fuchs Chemie),
[0086] Corax(R) N339 (carbon black, manufacturer Degussa Hьls AG),
[0087] Stearic acid,
[0088] ZnO (zinc oxide),
[0089] Sulfur,
[0090] Vulkanox(R) 4010 (N-isopropyl-N'-phenyl-p-diphenylenediamine, manufacturer Bayer AG),
[0091] Vulkanox(R)4020 (N-(1,3-dimethylbutyl)-N'phenyl-p-phenylenediamine, manufacturer Bayer
AG),
[0092] Vulkacit(R) D (diphenylguanidine, manufacturer Bayer AG),
[0093] Vulkacit(R) CZ/C (N-cyclohexyl-2-benzothiazyl-sulfenamide, manufacturer Bayer AG),
[0094] DOP: Vestinol AH, (dioctyl phthalate, Hьls AG),
[0095] DOS: Edenol 888, (dioctyl sebacate, Henkel KGaA),
[0096] TKP: Disflamoll TKP (tricresyl phosphate, Bayer AG).
[0097] The individual proportions by weight of the components are given in tables 4 and 6.
[0098] The components were mixed in a compounder (Werner & Pfleiderer GK 1.5) at 50 rpm. The
compounder temperature was 60[deg.] C. The vulcanization accelerators were admixed later on a
roller.
[0099] The results of the tests are given in tables 5 and 7.
TABLE 4
Example 4Example 5
DOP-25DOP-50
5 DOP10 DOPComp. example 1
SBR 1500808080
NSBR 10020
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Masterbatch with 25 phr DOP2500
Masterbatch with 50 phr DOP0300
Arom. mineral oil252030
DOP000
Carbon black N339505050
Stearic acid222
Zinc oxide333
Vulkanox 4010 NA111
Vulkanox 4020111
Sulfur222
Vulkacit CZ1.51.51.5
Vulkacit D0.20.20.2
Ps. by wt. of synthetic5100
plasticizer in the mixture, with
respect to rubber
[0100]
TABLE 5
Comp.
Vulcanizate propertiesExample 4Example 5example 1
Tensile strength(MPa)22.623.621.1
Extension at break(%)622620640
Modulus 100%(MPa)1.671.661.6
Modulus 300%(MPa)7.327.996.5
Hardness 23[deg.] C.(Shore A)585757
Hardness 70[deg.] C.(Shore A)515151
DIN abrasion 60(mm)133104140
tan [delta] 0[deg.] C.0.5670.5560.463
23[deg.] C.0.2990.2910.339
60[deg.] C.0.1900.1870.216
E* 0[deg.] C.30.77022.06062.777
23[deg.] C.8.0968.14910.555
60[deg.] C.4.9345.1215.2727
E' 0[deg.] C.26.76219.28359.973
23[deg.] C.7.7577.8239.995
60[deg.] C.4.8475.0345.598
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E'' 0[deg.] C.15.18510.71626.635
23[deg.] C.2.3202.2793.391
60[deg.] C.0.9200.9411.209
[0101] The results in table 5 show that masterbatches according to the present invention, as
compared with the prior art (comparison example 1), exhibit advantages such as much lower
dynamic moduli, higher tan [delta] values at 0[deg.] C. (better resistance to wet-skidding), lower tan
[delta] value at 60[deg.] C. (lower resistance to rolling) and lower DIN abrasion (less wear), with
sometimes improved tensile strengths. This also applies at low concentrations of polar plasticizers.
TABLE 6
Example 6Example 7
DOS-37.5TKP-37.5
7.5 DOS7.5 TKPComp. example 1
SBR 1500808080
NSBR 10020
Masterbatch with 37.5 phr27.500
DOS
Masterbatch with 37.5 phr027.50
TPK
Arom. Mineral oil22.522.530
DOP000
Carbon black N339505050
Stearic acid222
Zinc oxide333
Vulkanox 4010 NA111
Vulkanox 4020111
Sulfur222
Vulkacit CZ1.51.51.5
Vulkacit D0.20.20.2
Pts. by wt. of synthetic7.57.50
plasticizer in the mixture,
with respect to rubber
[0102]
TABLE 7
Vulcanizate propertiesExample 6Example 7Comp. example 1
Tensile strength21.823.121.1
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Extension at break627656640
Modulus 100%1.551.591.6
Modulus 300%76.96.5
Hardness 23[deg.] C.565657
Hardness 70[deg.] C.505051
DIN abrasion 60125135140
tan [delta] 0[deg.] C.0.5520.5840.463
23[deg.] C.0.2900.3040.339
60[deg.] C.0.1850.1900.216
E* 0[deg.] C.23.03428.27862.777
23[deg.] C.7.6227.99810.555
60[deg.] C.4.9094.8065.2727
E' 0[deg.]C.20.16824.41759.973
23[deg.] C.7.3217.6519.995
60[deg.] C.4.8274.7225.598
E'' 0[deg.] C.11.12714.26226.635
23[deg.] C.2.1212.3293.391
60[deg.] C.0.8940.8971.209
[0103] The results in table 7 show that masterbatches according to the present invention (examples
6 and 7), containing different polar plasticizers from masterbatches according to the present
invention in examples 4 and 5 are superior to the prior art (comparison example 1).
[0104] Although the invention has been described in detail in the foregoing for the purpose of
illustration, it is to be understood that such detail is solely for that purpose and that variations can be
made therein by those skilled in the art without departing from the spirit and scope of the invention
except as it may be limited by the claims.Claims:
What is claimed is:
1. Rubber mixtures comprising
a) at least one terpolymer (NSBR) which comprises an olefinically unsaturated nitrile, a vinylaromatic
compound and a conjugated diene; and
b) at least one polar synthetic plasticizer,
wherein component b) is present in an amount of 0.5 to 50 wt. %, with respect to the amount of
terpolymer (a).
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2. Rubber mixtures according to claim 1, wherein said rubber mixtures comprise at least one other
synthetic or natural rubber or mixtures of the same, wherein the amount of added rubber is 1 to 99
wt. %, with respect to the total amount of rubber.
3. Vulcanizates comprising rubber mixtures, which contain
a) at least one terpolymer (NSBR) comprising an olefinically unsaturated nitrile, a vinylaromatic
compound and a conjugated diene; and
b) at least one polar synthetic plasticizer,
wherein component b) is present in an amount of 0.5 to 50 wt. %, with respect to the amount of
terpolymer (a).
4. Vulcanizates comprising rubber mixtures, which contain
a) at least one terpolymer (NSBR) comprising an olefinically unsaturated nitrile, a vinylaromatic
compound and a conjugated diene; and
b) at least one polar synthetic plasticizer, and
c) at least one other synthetic or natural rubber or mixtures of the same,
wherein component b) is present in an amount of 0.5 to 50 wt. %, with respect to the amount of
terpolymer (a). and wherein component c) is present in an amount of 1 to 99 wt. %, with respect to
the total amount of rubber.
5. The vulcanizates according to claim 3 and 4, wherein said vulcanizates are tire components or
industrial rubber goods.
6. A process for producing rubber mixtures having
a) at least one terpolymer (NSBR) which comprises an olefinically unsaturated nitrile, a vinylaromatic
compound and a conjugated diene; and
b) at least one polar synthetic plasticizer,
wherein component b) is present in an amount of 0.5 to 50 wt. %, with respect to the amount of
terpolymer (a), comprising the step of mixing NSBR terpolymers in latex form with polar synthetic
plasticizers to obtain a mixture, mutually coagulating the mixture and then drying the mixture.
158/425
18. JP2002309224 - 17.10.2002
ADHESIVES FOR INCREASING THE ADHESION BETWEEN RUBBERS AND REINFORCING
MATERIALS
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2002309224
Inventor(s):
JANSEN BERNHARD [DE] (--); SCHUBART RUDIGER [DE] (--); GRABOWSKI
STEFAN [DE] (--); WEIDENHAUPT HERMANN-JOSEF [DE] (--)
IP Class 4 Digits: C09J
IP Class:
C9J4/00
E Class: C08J5/10+L21/00
Application Number:
US20020061860 (20020201)
Priority Number: DE20011005402 (20010207)
Family: JP2002309224
Equivalent:
CA2370407; DE10105402; EP1233045
Abstract:
THE PRESENT INVENTION RELATES TO ADHESIVES FOR INCREASING THE ADHESION BETWEEN
RUBBERS AND REINFORCING MATERIALS BASED ON METALS, ORGANIC POLYMERS OR
CERAMIC MATERIALS AND THE USE OF ADHESIVES TO PRODUCE RUBBER MIXTURES OR
RUBBER VULCANIZATES CONTAINING REINFORCING MATERIALS. THE ADHESIVES
ACCORDING TO THE INVENTION ARE CHARACTERIZED BY SIMPLE AND ENVIRONMENTALLY
FRIENDLY PROCESSING COMBINED WITH A VERY GOOD ADHESIVE EFFECT.Description:
FIELD OF THE INVENTION
[0001] The subject of the present invention is adhesives for increasing the adhesion between
rubbers and reinforcing materials based on metals, organic polymers or ceramic materials and the
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use of the adhesives for producing rubber mixtures or rubber vulcanizates containing reinforcing
materials.
BACKGROUND OF THE INVENTION
[0002] Many industrial rubber articles, for example pneumatic tires, conveyor belts, drive belts,
rubberized fabrics or high pressure hoses are equipped with reinforcing inserts, called reinforcing
materials in this case, which contain metallic materials, organic polymer materials or ceramic
materials, preferably in the form of filaments, fibers, wires, cords, strips or combinations thereof.
[0003] To ensure that the aforementioned rubber articles are efficient and have a good useful life, a
strong and durable bond is required between the reinforcing materials and the rubber.
[0004] This may only be achieved, for example in the case of the insertion of steel cord as reinforcing
material, without a further adhesive if the filaments of the steel cord are plated with a thin layer of
brass or another alloy with the main components being copper and zinc or pure zinc.
[0005] The steel cord, which is equipped in this way, is vulcanized directly into the generally
particularly adhesion-promoting rubber mixture containing rubber mixture additives. In the case of
textile reinforcing materials, fibers surface-treated in a suitable form are conventionally used.
[0006] The most common additives for improving the adhesive force, hereinafter designated
adhesives, may be divided into two groups in accordance with their chemical structure.
[0007] The first group contains all adhesives, which are only effective as multi-component systems.
Common thereto is the fact that they contain highly reactive silicas.
[0008] The further components are resorcinol or resorcinol formaldehyde condensation products and
formaldehyde-splitting compounds such as hexamethylenetetramine, etherified esterified methylol
melamines with various degrees of etherification or esterification and the condensation products
thereof.
[0009] While these systems provide good adhesion, they sometimes cause vapors and bad odors
during vulcanization. The processability in the mixing machines, for example on the mixing mill, is
also considerably impaired as the resorcinol tends toward sublimation, particularly at temperatures
close to the melting point.
[0010] The second group primarily contains organometallic compounds, with the compounds of
cobalt predominating. Cobalt soaps, are also conventional as liquid dryers in the paint industry, have
primarily been used for a long time.
[0011] Therefore, in FR-A 1 323 934, various cobalt salts, for example cobalt stearate, cobalt linolate
or cobalt naphthenate are claimed. Boronorganic cobalt compounds, in accordance with U.S. Pat.
No. 3,296,242, are suitable. Copper, nickel, lead or zinc can also be considered as metals in
addition to cobalt (cf. DE-A 2,303,674, DE-A 2,447,853 or U.S. Pat. No. 4,154,911).
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[0012] Further compound classes are nickel and cobalt complexes of succincyl succinic acid esters
(EP-A 0 003 820) or transition metal salts of certain 1, 2 diols (EP-A 0 009 000).
[0013] Simple organic salts do not generally improve the adhesion of a rubber compound to metallic
carrier materials, but rather, in contrast, as a rubber poison, often reduce the stability of the
rubber/metal compounds.
[0014] The harmful effect of the adhesives used hitherto is also worth mentioning. Thus, resorcinol
and resorcinol polycondensates tend to form harmful vapors during processing due to the
sublimation of the resorcinol. Cobalt and bioavailable cobalt compounds are also carcinogenic.
SUMMARY OF THE INVENTION
[0015] Therefore, the object of the invention is to provide an adhesive system for improved rubber
adhesion to reinforcing materials which does not exhibit the aforementioned drawbacks or does not
exhibit them to the same extent and which, in particular, does not contain any heavy metals such as
cobalt or nickel either.
[0016] The invention, therefore, relates to adhesives for increasing the adhesion between rubbers
and reinforcing materials wherein compounds are contained which a) can be obtained by reacting
carboxylic acids with compounds which have one or more hydroxyl groups or one or more amino
groups or one or more hydroxyl and one or more amino groups and additionally one or more carboncarbon double or triple bonds in the molecule and optionally, with compounds which contain one or
more hydroxyl groups or one or more primary or secondary amino groups or one or more hydroxyl
and one or more primary or secondary amino groups and additionally, at least one tertiary amino
group in the molecule, or b) can be obtained by reacting polyisocyanates with compounds which
contain one or more hydroxyl groups or one or more amino groups or one or more hydroxyl and one
or more amino groups and additionally, one or more carbon-carbon double or triple bonds in the
molecule and optionally, with compounds which contain one or more hydroxyl groups or one or more
primary or secondary amino groups or one or more hydroxyl and one or more primary or secondary
amino groups and additionally at least one tertiary amino group in the molecule.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Practically, all known carboxylic acids, in particular those which contain at least two
carboxylic groups, preferably 2 to 4 carboxylic groups in the molecule and 2 to 40 carbon atoms,
preferably 4 to 36 carbon atoms in the molecule are considered as carboxylic acids.
[0018] The carboxylic acids which can be used according to the present invention can, of course, be
substituted by the most varied of groups, such as hydroxyl groups, halogens, nitro groups, alkyl
groups or aryl groups.
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[0019] The substituents can be present singly or multiply in the above-mentioned carboxylic acids. It
is also possible to use carboxylic acids of this type which are interrupted singly or multiply, by
heteroatoms, such as oxygen, sulfur or nitrogen and unsaturated structures such as double bonds.
[0020] Preferred examples of carboxylic acids are: maleic acid, fumaric acid, itaconic acid, oxalic
acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid,
dodecanedioic acid, malic acid, tartaric acid, butanetetracarboxylic acid, diglycol acid, thiodiglycol
acid, citric acid, mucic acid, camphoric acid, hexahydroterephthalic acid, HET acid, phthalic acid,
isophthalic acid, terephthalic acid, tetrachlorophthalic acid, 4-chloro-1,3-benzenedicarboxylic acid,
1,3,5-benzenetetracarboxylic acid, pyromellitic acid, 4-phenylphthalic acid, 1,4,5,8naphthalenetetracarboxylic acid and dimeric fatty acid as described in the monograph: "THE DIMER
ACIDS", edited by Erward C. Leonhard, Humko Sheffield Chemical, in particular maleic acid, fumaric
acid, itaconic acid, malonic acid, succinic acid, adipic acid, phthalic acid, isophthalic acid and the
dimeric fatty acids described in the monograph.
[0021] Maleic acid, fumaric acid, malonic acid, adipic acid and dimeric fatty acids are most
preferably used.
[0022] Of course, it is possible to use mixtures of the above-mentioned carboxylic acids.
[0023] Examples of compounds which exhibit one or more hydroxyl groups or one or more amino
groups or one or more hydroxyl and one or more amino groups and additionally one or more carboncarbon double or triple bonds in the molecule are: allyl alcohol, 2-methyl-3-buten-2-ol, olein alcohol,
propargyl alcohol, 3-butin-2-ol, 2-methyl-3-butin-2-ol, allylamine and diallylamine, preferably allyl
alcohol, olein alcohol and propargyl alcohol.
[0024] Allyl alcohol, olein alcohol, allylamine and diallylamine are preferably used for the reaction
with the polyisocyanates described hereinafter.
[0025] The amino and hydroxy compounds just mentioned can be used both individually and in a
mixture with one another.
[0026] Compounds which can be used in addition to the above-mentioned compounds containing
hydroxyl groups or amino groups are, as mentioned, those which contain one or more hydroxyl
groups or one or more primary or secondary amino groups or one or more hydroxyl and one or more
primary or secondary amino groups and additionally at least one tertiary amino group in the molecule,
examples thereof being: N,N-dimethyl- and N,N-diethylethanolamine, 2-(2-dimethyl-aminoethoxy)ethanol, 2-(2-diethyl-aminoethoxy)-ethanol, N,N-dibutylaminoethanol, N-methyidiethanolamine, Nbutyldiethanolamine, bis-(2-hydroxyethyl)oleylamine, triethanolamine, (3-hydroxypropyl)dimethylamine, (2-hydroxypropyl)-dimethylamine, 1-diethylamino-2-propanol, bis-(2-hydroxypropyl)methylamine, tris-(2-hydroxypropyl)-amine, N,N-diethyl-1,2-ethaneamine, N,N',N''-
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trimethyldiethylenetriamine, N,N-dimethyl-1,3-propanediamine, N,N-diethyl-1,3-propanediamine, bis(3-aminopropyl)-methylamine.
[0027] N,N-dimethyl- and N,N-diethylethanolamine, N,N-dibutylaminoethanol, 2-(2-dimethylaminoethoxy)-ethanol are preferred. These compounds can be used both individually and in a
mixture with one another.
[0028] The known modified or unmodified aliphatic, cycloaliphatic, araliphatic or aromatic
polyisocyanates, both individually and in a mixture with one another, can be used as polyisocyanates.
Aliphatic, cycloaliphatic, araliphatic and/or aromatic polyisocyanates which exhibit uretdione and/or
isocyanurate- and/or allophanate and/or biuret- and/or oxadiazine structures and which can be
produced in the known manner from the above-mentioned polyisocyanates are preferably used.
Examples of aliphatic or cycloaliphatic diisocyanates are: 1,4-diisocyanatobutane, 1,6diisocyanatohexane, 1,5-diisocyanato-2,2-dimethyl-pentane, 2,2,4- and 2,4,4-trimethyl-1,6diisocyanatohexane, 1,3- and 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5isocyanato-methyl-cyclohexane, 1-isocyanato-1-methyl-4-isocyanatomethyl-cyclohexane, 4,4diisocyanato-dicyclohexylmethane or any mixtures of the aforementioned diisocyanates. 1,6diisocyanatohexane, 1,4-diisocyanatocyclohexane and 1-isocyanato-3,3,5-trimethyl-5, isocyanatomethyl-cyclohexane are preferred.
[0029] Toluylene diisocyanate and its isomer mixtures, 1,5-diisocyanatonaphthalene and
diphenylmethane diisocyanates are examples of aromatic polyisocyanates.
[0030] As mentioned previously, the polyisocyanates mentioned by name can be modified with the
aforementioned structures.
[0031] Polyisocyanates which are modified by uretdione and/or isocyanurate structures and/or
allophanate and/or biuret structures are preferably used.
[0032] To produce the adhesives according to the present invention, the above-mentioned
carboxylic acids are reacted, individually or in a mixture with one another, with the above-mentioned
unsaturated compounds containing hydroxyl and/or amino groups in such a way that 0.1 to 1.0 mol
of the unsaturated compounds containing hydroxyl and/or amino groups and 0.1 to 0.9 mol of the
compounds containing tert.-amino groups are used on 1 mol carboxyl groups. 0.3 to 1.0 mol of the
compounds containing unsaturated hydroxyl and/or amino groups and 0.3 to 0.7 mol of the
compounds containing tert.-amino groups are preferably used on 1 mol carboxyl groups.
[0033] To produce the adhesives according to the present invention based on polyisocyanates, the
above-mentioned polyisocyanates are reacted with the unsaturated compounds containing hydroxyl
and/or amino groups in such a way that 0.1 to 1 mol of the unsaturated compounds containing
hydroxyl and/or amino groups and 0.3 to 0.7 mol of the compounds containing tert.-amino groups
are allotted to 1 mol isocyanate groups. 0.3 to 1 mol of the compounds containing unsaturated
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hydroxyl and/or amino groups and 0.3 to 0.7 mol of the compounds containing tert.-amino groups
are preferably used on 1 mol isocyanate groups.
[0034] Production of the adhesives according to the present invention from the above-mentioned
components is known and can, for example, be carried out in accordance with the melt ester
process in a solvent-free manner when using carboxylic acids or in the form of an azeotropic, an
extractive esterification using dehydrating means. The esterification reactions are described, for
example, in Organikum, 14th edition, VEB Deutscher Verlag der Wissenschaften, Berlin, 1965, page
440 to 443. Of course, a mode of operation for esterification purposes is also possible which
proceeds from the anhydrides of the above-mentioned carboxylic acids.
[0035] Reaction of the above-mentioned polyisocyanates with the compounds containing hydroxyl or
amino groups is also state of the art and is described, for example, in Houben-Weyl, Methoden der
Organischen Chemie, Makromolekulare Stoffe, volume E20, part 2, page 1587 to 1609.
[0036] The present invention also relates to the use of the adhesives according to the present
invention to produce rubber mixtures or rubber vulcanizates containing reinforcing materials which
can exist in the most varied of forms.
[0037] The known reinforcing materials as they are used to produce corresponding rubber articles
can be considered as reinforcing materials. Examples include steel cord, steel cord in galvanized or
brass-plated form, textile fibers, such as cellulose fibers, viscose fibers, polyester fibers, polyamide
fibers, aramide fibers and polyethylene fibers, carbon fibers or glass fibers and fibers based on
ceramic materials. The reinforcing materials can optionally be surface-modified by the current
processes.
[0038] Both natural rubber and the conventional synthetic rubbers can be considered as rubbers,
which can be used to produce the rubber mixtures or rubber vulcanizates containing reinforcing
materials. Rubbers based on butadiene, butadiene/acrylic acid C1 to C4 alkylesters, chloroprene,
isoprene or isoprene copolymers, styrene/butadiene copolymers, styrene/butadiene/acrylonitrile
copolymers, isobutylene/isoprene copolymers, butadiene/acrylonitrile copolymers, partially
hydrogenated or completely hydrogenated butadiene/acrylonitrile copolymers,
ethylene/propylene/diene copolymers are examples.
[0039] Of course, the above-mentioned rubbers can be used alone or in mixtures with one another.
The most preferred mixture ratio of the rubbers to be used is determined in accordance with the
subsequent application of the rubber mixtures or rubber vulcanizates.
[0040] Natural rubber and rubbers based on butadiene and styrene/butadiene copolymers are
preferably used.
[0041] The adhesives according to the present invention are conventionally used in quantities of 0.01
to 20 parts by weight, preferably in quantities of 0.05 to 5 parts by weight, most particularly
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preferably in quantities of 0.1 to 1.5 parts by weight, based on 100 parts by weight rubber (=phr) to
produce rubber mixtures or rubber vulcanizates.
[0042] Of course, it is possible to combine the adhesives according to the present invention with the
adhesive systems hitherto used in practice.
[0043] To produce the rubber mixtures or rubber vulcanizates containing reinforcing materials by
using the adhesives according to the present invention, the known rubber auxiliary aids and crosslinking agents or cross-linking systems can be admixed to the rubber mixtures in the quantities
known for this purpose.
[0044] Rubber auxiliary agents and cross-linking agents or cross-linking systems of this type are
described in more detail, for example, in Ullmann's Encyclopedia of Industrial Chemistry, fifth
completely revised edition, volume A23, page 365 to 420.
[0045] The adhesives according to the present invention and rubber mixtures containing reinforcing
materials are vulcanized in the conventional manner at temperatures in the range of 100 to 200[deg.]
C., preferably at 130 to 180[deg.] C., optionally under pressure of 10 to 200 bar.
[0046] Rubber articles of all kinds containing reinforcing materials can be produced with the
adhesives according to the invention, for example conveyor belts, driving belts, hoses, tire
components or rubberized fabrics.
EXAMPLES
[0047] The rubber polymers and chemicals are commercial products from Bayer AG Rubber Division,
unless otherwise stated. The rubber-mechanical tests were carried out to DIN 53523, 53504, 53505
53512, 53513 and ASTM D 2084.
[0048] The adhesion test was carried out to ASTM D 2229.
Example 1
[0049] Production of the a) and b) Type Adhesives
[0050] Adhesive a):
[0051] Maleic acid diallylester, which can be obtained from Fluka under Article No. 63230.
[0052] Adhesive b):
[0053] 100 parts by weight of an isocyanate with the NCO content of 22.5%, substantially containing
trimeric hexamethylene diisocyanate, were stirred at ambient temperature with 29.7 parts by weight
allyl alcohol. The reaction mixture was then heated to 60[deg.] C. and stirred until an isocyanate
absorption is no longer visible in the infrared spectrum. The resulting product was a highly viscous
honey yellow substance.
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Example 2
[0054] Production of Adhesive Mixtures
[0055] The components polymer, filler and additives including the a) and b) type adhesives
according to the invention were mixed in a 1.5 l closed mixer from Werner & Pfleiderer (GK 1.5 E
model):
[0056] Sulfur and accelerator at approximately 60 to 90[deg.] C. were subsequently admixed on a
roller.
[0057] Diverse specimens were produced in a manner conventional to the person skilled in the art in
a press vulcanization process at 150[deg.] C.
[0058] Specimens were subsequently punched out of these plates in a conventional manner in order
to carry out the rubber-mechanical tests mentioned in Table 1.
[0059] In addition, composite specimens of the rubber mixtures and brass-plated steel cord were
produced and vulcanized. This also took place in a manner conventional to the person skilled in the
art to ASTM D 2229.
Components used:
Vulkanox (R) HSdihydroquinoline (polymerized), Bayer AG
product
Vulkacit (R) DZsulfenamide, Bayer AG product
Koresin (R) Powdertackifier resin, BASE AG product
Rhenocure (R) IS 90-20insoluble sulfur 80%, Rhein Chemie Rheinau
product
TSR 5 Defo 700natural rubber
Corax (R) N326carbon black, Degussa-Hьls AG product
Stearic acidHenkel KGaA product
Zinkoxyd aktiv (R)Bayer AG product
Steel cordBekaert AG product
[0060] The individual mixture compositions are given in the following Table 1:
TABLE 1
ComparisonMixture AMixture B
mixture(invention)(invention)
TSR 5 Defo 700100100100
Corax N 326606060
Stearic acid222
Koresin owder444
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Vulkanox HS0.80.80.8
Zinkoxyd aktiv888
a) type adhesive (invention)0.63
b) type adhesive (invention)0.63
Vulkacit DZ111
Rhenocure IS 90-20555
[0061] The rubber-mechanical properties of the rubber mixtures and the vulcanizates and reinforced
rubber specimens produced therefrom are listed in the following tables 2 to 4:
TABLE 2
Mixture properties
ComparisonMixture AMixture B
mixture(invention)(invention)
Mooney Viscosity [ME]567654
Mooney Scorch (min)12.514.612.3
ts 01 [min]1.441.291.52
t 90 [min]17.3116.7517.96
[0062]
TABLE 3
Vulcanizate properties
ComparisonMixture AMixture B
mixture(invention)(invention)
Module 100 [MPa]3.74.23.8
Module 300 [MPa]16.218.216.0
Strength [MPa]27.225.527.1
Elongation at break [%]457408459
Tear propagation resistance50.347.052.8
23[deg.] C.
Tear propagation resistance34.7-35.2
70[deg.] C.
Shore A hardness, 23[deg.] C.727574
Shore A hardness, 70[deg.] C.707070
Elasticity 23[deg.] C. [%]41.642.741.0
Elasticity 70[deg.] C. [%]54.057.150.2
[0063] 3]lsqb;0063]
TABLE 4
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Adhesion properties
ComparisonMixture AMixture B
mixture(invention)(invention)
Peel force [N]670746722
Cord covering* 4- 3
*1 = base; 2 = partially covered; 3 = completely covered; 4 = structural fracture in the rubber
[0064] Generally, a high extraction force with a high degree of coverage with the precondition that
the remaining properties of rubber mixture and vulcanizate are comparable are valid criteria for
rubber mixtures which are suitable for producing by vulcanization composite materials with the
above-mentioned reinforcing materials. The examples show that the adhesives according to the
present invention and the adhesive mixtures produced therewith are eminently suitable for this
purpose.
[0065] Although the invention has been described in detail in the foregoing for the purpose of
illustration, it is to be understood that such detail is solely for that purpose and that variations can be
made therein by those skilled in the art without departing from the spirit and scope of the invention
except as it may be limited by the claims.Claims:
What is claimed is:
1. An adhesive composition for increasing the adhesion between rubbers and reinforcing materials,
wherein said adhesive composition comprises compounds which are obtained by reacting
carboxylic acids with compounds which have one or more hydroxyl groups or one or more amino
groups or one or more hydroxyl and one or more amino groups and additionally one or more carboncarbon double or triple bonds in the molecule and optionally with compounds which contain one or
more hydroxyl groups or one or more primary or secondary amino groups or one or more hydroxyl
and one or more primary or secondary amino groups and additionally at least one tertiary amino
group in the molecule.
2. An adhesive composition according to claim 1, wherein the carboxylic acids are reacted with the
unsaturated compounds containing hydroxyl and/or amino groups in such a way that 0.1 to 1.0 mol
of the compounds containing hydroxyl and/or amino groups and 0.1 to 0.9 mol of the compounds
containing tert-amino groups are used on 1 mol carboxylic groups.
3. Rubber mixtures or rubber vulcanizates containing reinforcing materials which comprise an
adhesive composition for increasing the adhesion between rubbers and reinforcing materials,
wherein said adhesive composition comprises compounds which are obtained by reacting
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carboxylic acids with compounds which have one or more hydroxyl groups or one or more amino
groups or one or more hydroxyl and one or more amino groups and additionally one or more carboncarbon double or triple bonds in the molecule and optionally with compounds which contain one or
more hydroxyl groups or one or more primary or secondary amino groups or one or more hydroxyl
and one or more primary or secondary amino groups and additionally at least one tertiary amino
group in the molecule.
4. An adhesive composition for increasing the adhesion between rubbers and reinforcing materials,
wherein said adhesive composition comprises compounds which are obtained by reacting
polyisocyanates with compounds which contain one or more hydroxyl groups or one or more amino
groups or one or more hydroxyl and one or more amino groups and additionally one or more carboncarbon double or triple bonds in the molecule and optionally with compounds which contain one or
more hydroxyl groups or one or more primary or secondary amino groups or one or more hydroxyl
and one or more primary or secondary amino groups and additionally at least one tertiary amino
group in the molecule.
5. An adhesive composition according to claim 4, wherein the polyisocyanates are reacted with the
unsaturated compounds containing hydroxyl and/or amino groups and with the compounds
containing tert.-amino groups in such a way that 0.1 to 1.0 mol of the unsaturated compounds
containing hydroxyl and/or amino groups and 0.3 to 0.7 of the compounds containing tert.-amino
groups are allocated to 1 mol isocyanate groups.
6. Rubber mixtures or rubber vulcanizates containing reinforcing materials which comprise an
adhesive composition for increasing the adhesion between rubbers and reinforcing materials,
wherein said adhesive composition comprises compounds which are obtained by reacting
polyisocyanates with compounds which contain one or more hydroxyl groups or one or more amino
groups or one or more hydroxyl and one or more amino groups and additionally one or more carboncarbon double or triple bonds in the molecule and optionally with compounds which contain one or
more hydroxyl groups or one or more primary or secondary amino groups or one or more hydroxyl
and one or more primary or secondary amino groups and additionally at least one tertiary amino
group in the molecule.
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19. JP2002356557 - 05.12.2002
BLOCK COPOLYMER BASED ON CONJUGATED DIOLEFINS AND POLAR MONOMERS
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2002356557
Inventor(s):
OBRECHT WERNER (DE); WINDISCH HEIKE (DE); STERE CRISTINA (DE);
SCHOLL THOMAS (DE); NUYKEN OSKAR (DE); FRIEBE LARS (DE); VIERLE MARIO (DE); SCHOLL
ULRIKE (DE); SCHOLL PHILIPP (DE); SCHOLL CHRISTINE (DE); SCHOLL JOHANNES (DE)
IP Class 4 Digits: C08F
IP Class:
C8F4/44
E Class: C08F297/06
Application Number:
US20020102761 (20020321)
Priority Number: DE20011015106 (20010327)
Family: JP2002356557
Equivalent:
CA2378498; DE10115106; EP1245600; US6734257
Abstract:
THE BLOCK COPOLYMERS ACCORDING TO THE INVENTION WHICH ARE BASED ON
CONJUGATED DIOLEFINS AND POLAR MONOMERS AND ARE PREPARED IN THE PRESENCE OF
CATALYSTS BASED ON THE RARE EARTH METALS HAVE A HIGH CIS-1,4 CONTENT IN THE
POLYDIENE BLOCK AND, BECAUSE OF THEIR POLAR POLYMER PART AND THEIR NON-POLAR
DIENE POLYMER PART, CAN BE USED AS AGENTS WHICH IMPART COMPATIBILITY IN THE
PREPARATION OF VULCANIZATES WITH A FILLER CONTENT FOR THE PRODUCTION OF TIRES
AND TIRE COMPONENTS, AS A FILLER IN THE PREPARATION OF SUCH VULCANIZATES, AND AS
A BLEND COMPONENT IN THE PREPARATION OF THERMOPLASTIC ELASTOMERS OR IN THE
MODIFICATION OF THERMOPLASTICS.Description:
FIELD OF THE INVENTION
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[0001] The present invention relates to a block copolymer based on conjugated diolefins and polar
monomers, and to a process for the preparation of the block copolymer in the presence of catalysts
of the rare earths.
BACKGROUND OF THE INVENTION
[0002] The polymerization of conjugated diolefins has been known for a long time and is described,
for example, by W. Hoffman, Rubber Technology Handbook, Hanser Publishers (Carl Hanser Verlag)
Munich, Vienna, N.Y., 1989. Thus, for example, polybutadiene is now predominantly prepared by
solution polymerization with the aid of coordination catalysts of the Ziegler-Natta type, for example
based on compounds of titanium, cobalt, nickel and neodymium, or in the presence of alkyllithium
compounds. The nature of the solvent used in each case depends greatly on the type of catalyst
employed. Benzene or toluene and aliphatic or cycloaliphatic hydrocarbons are preferably employed.
[0003] The polymerization of unsaturated organic compounds, in particular conjugated dienes, in the
presence of catalysts based on rare earth metals has been known for a long time (see e.g. DE-A 28
33 721, U.S. Pat. No. 4,429,089, EP-A 76 535, EP-A 92 270, EP-A 92 271, EP-A 207 558, WO-A
93/05083, U.S. Pat. No. 5,627,119, EP-A 667 357, U.S. Pat. No. 3,478,901, EP-A 637 589). Thus, for
example, EP-A 11 184 and EP-A 7027 disclose a catalyst system which is based on rare earth metals,
in particular based on neodymium compounds, and is particularly suitable for the polymerization of
conjugated dienes, in particular butadiene. In the polymerization of, for example, butadiene, these
catalysts give a polybutadiene in very good yields and with a high selectivity, which is distinguished,
in particular, by a high content of cis-1,4 units.
[0004] It is, furthermore, known to employ anionic initiators, such as butyllithium, for the
polymerization of butadiene in hexane. Anionic catalysts are also suitable for a block
copolymerization of butadiene with further non-polar monomers, such as styrene and isoprene, or
polar monomers, such as ethylene oxide, propylene oxide and acrylates [H. L. Hsieh, R. P. Quirk,
Marcel Dekker Inc., New York-Basel, 1996; R. K. Sadhir, R. M. Luck, Expanding Monomers, CRC
Press Boca Raton, 1992]. In this case, the butadiene is first polymerized in an inert solvent and, after
addition of a further-monomer to the live system, a second block is then formed from the further
monomer. The preparation of three-block copolymers is also possible with these anionic initiators.
[0005] The disadvantage is that it is not possible, with anionic initiators, to prepare a copolymer with
a high cis content, in which the cis-1,4 content of the butadiene block is above 50%, under
conditions which are relevant in use.
[0006] It is known that compounds for tire mixtures, in particular for treads, are made of several
rubbers and fillers in order to achieve an optimum in their properties, such as e.g. the rolling
resistance and the abrasion and wet skidding resistance. Polydienes with a high cis content, such as
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the two synthetic rubbers, polybutadiene and polyisoprene or natural rubber, are preferably
employed in these rubbers.
[0007] To reduce the rolling resistance, some of the filler carbon black in the "green tires" is replaced
by silica. One of the main problems of using silica as a filler in rubber is the great difference in
polarity between the two components. This results in a poor miscibility. Binding of polar silica to the
non-polar rubber matrix has hereto been achieved only by means of coupling reagents, such as e.g.
Si-69(R) (Degussa AG).
[0008] However, for use of the block copolymer as an agent which imparts compatibility of, for
example, high cis-BR and silica in vulcanizate mixtures, a low cis-1,4 content in the polydiene part of
the block copolymer has an adverse effect on the compatibility of the block copolymer with the high
cis-BR rubber matrix and therefore, an adverse effect on the product properties.
[0009] In the case of catalysts based on the rare earths, those catalyst systems which allow
homopolymerization of polar monomers are also described. Examples of these are the samarium
catalyst [(C5Me5)SmH]2 for the polymerization of acrylates [H. Yasuda et al., Macromolecules, 1993,
22,7134; J. Am. Chem. Soc., 1992, 114, 4908; E. Ihara et al., Macromolecules, 1995, 28, 7886] and
lactones [M. Yamashita et al., Macromolecules, 1996, 29, 1798] and for the block copolymerization of
ethylene with methacrylate or [epsilon]-caprolactone [H. Yasuda et al., Macromolecules, 1992,25,
5115], the samarium catalyst [(C5Me5)25 mMe] for the formation of tri-block copolymers from
variously substituted acrylates [E. Ihara et al., Macromolecules, 1995, 28, 7886] and for the
polymerization of cyclic carbonates [H. Yasuda, Prog. Polym. Sci., 2000, 25, 573], the ytterbium
catalyst Yb[C(SiMe3)3]2 for the polymerization of methacrylate [H. Yasuda et al., Prog. Polym. Sci.,
1993,18,1097; E. Ihara et al., J. Organomet. Chem., 1999, 574, 40] and neodymium catalysts based
on Nd(acac)3(H2O)3/AIR3 and Nd(naphthenate)3/AIR3 for the polymerization of lactones [Z. Shen et
al., J: Polym. Sci., Polym. Chem. Ed., 1994, 32, 597] and based on Nd(ethyl acetoacetate)2(OPr) for
the block copolymerization of cyclic carbonate with lactones [H. Yasuda, Prog. Poly. Sci., 2000, 25,
573].
[0010] The preparation of block copolymers with a high cis-1,4-polydiene part and therefore, a low
glass transition temperature has not so far been possible.
SUMMARY OF THE INVENTION
[0011] The object of the present invention was to provide a process for the block copolymerization of
conjugated diolefins and polar monomers with which copolymers in which the polymer composition
can be varied with respect to the content of conjugated dienes and of polar monomers, at an
unchanged high cis-1,4 content in the polydiene content of >=60%, are obtained.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows TEM photograph of a PB/PCL mixture (weight content of PCL=62%) after
dissolving in CHCl3 and precipitation. Contrasted by OsO4, ultra-thin section. Dark regions: PB, grey
regions: PCL, white regions: holes. Bar length: 10 [mu]m.
[0013] FIG. 2 shows a TEM photograph of the polymer at the phase boundary isolated by FEEF
(weight content of PCL=70%, contains PB-block-PCL). Contrasted by OsO4, ultra-thin section. Dark
regions: PB, light regions: PCL.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The present invention relates to a process for the block copolymerization of conjugated
diolefins and polar monomers with which copolymers in which the polymer composition can be
varied with respect to the content of conjugated dienes and of polar monomers, at an unchanged
high cis-1,4 content in the polydiene content of >=60%, preferably >=80%, more preferably >=90%,
are obtained.
[0015] With the catalyst systems according to the present invention described in more detail below,
there is the possibility of preparing a block copolymer in which the content of polymerized dienes
and polar monomers can be adjusted within a wide range at an unchanged high cis-1,4 content of
the polydiene. These block copolymers with a high cis content are not possible with the known
catalyst systems used in the art which are based on lithium-alkyls.
[0016] With the catalyst systems employed according to the present invention, it is, therefore,
possible to establish a high cis-1,4 content in the polydiene content, in order to achieve in this
manner, an optimum compatibility with the rubbers of high cis content employed, while also, via
establishing of a suitable ratio of polymerized dienes and of polymerized polar monomers, to ensure
optimum binding of the rubber mixture to polar components, which manifests itself in low abrasion
and a long life in the industrial use of the mixtures.
[0017] The present invention, therefore, provides a block copolymer based on conjugated dienes
and polar monomers, which is characterized in that it comprises the polymerized conjugated dienes
in amounts of 5 to 95 wt. % and the polymerized polar monomers in amounts of 95 to 5 wt. %, the
polydienes having a cis-1,4 content of >=60%.
[0018] Preferably, the amount of dienes is 20 to 90 wt. % and the amount of polar monomers is 10 to
80 wt. %, the polydienes having a cis-1,4 content of >=80%, preferably >=90%.
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[0019] The present invention also provides a process for the preparation of block copolymers based
on conjugated dienes and polar monomers, which is characterized in that conjugated dienes are
polymerized in the presence of catalysts comprising
[0020] A) at least one compound of the rare earth metals,
[0021] B) at least one organoaluminum compound and
[0022] C) at least one Lewis acid
[0023] and in the presence of inert organic solvents up to a conversion of >=50%, preferably >=70%,
polar monomers are then added to the polymerization mixture and polymerization is carried out up to
a conversion of >=30%, preferably >=50%, and the resulting block copolymer is then isolated, the
conjugated dienes being employed in the reaction mixture in amounts of 5 to 30 wt. %, preferably 1020 wt. %, and the polar monomers in amounts of 1 to 30 wt. %, preferably 5-20 wt. %.
[0024] The molar ratio in which catalyst components (A) to (C) are employed can be varied within
wide limits. The molar ratio of component (A) to component (B) is 1:1 to 1:1,000, preferably 1:3 to
1:200, more preferably 1:3 to 1:100. The molar ratio of component (A) to component (C) is 1:0.2 to
1:15, preferably 1:0.4 to 1:5, more preferably 1:0.5 to 1:3. If alumoxanes are used as component (B),
all or some of component (C) can be dispensed with.
[0025] Possible compounds of the rare earth metals (component (A)) are, in particular, those which
are chosen from:
[0026] an alcoholate of the rare earth metals,
[0027] a phosphonate, phosphinates and/or phosphates of the rare earth metals,
[0028] a carboxylate of the rare earth metals,
[0029] a complex compound of the rare earth metals with diketones
[0030] an addition compound of the halides of the rare earth meals with an oxygen or nitrogen donor
compound and/or
[0031] an allyl compound of the rare earth metals.
[0032] The above-mentioned compounds of the rare earth metals are described in more detail, for
example, in EP-B-01 1184 and WO 96/31544.
[0033] The compounds of the rare earth metals are based, in particular, on the elements with the
atomic numbers 21, 39 and 57 to 71. Rare earth metals which are preferably employed are
lanthanum, praseodymium or neodymium or a mixture of elements of the rare earth metals which
comprises at least one of the elements lanthanum, praseodymium or neodymium to the extent of at
least 10 wt. %. Lanthanum or neodymium are preferably employed as rare earth metals, and these, in
turn, can be mixed with other rare earth metals. The content of lanthanum and/or neodymium in such
a mixture is preferably at least 30 wt. %.
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[0034] Possible alcoholates, phosphonates, phosphinates, phosphates and carboxylates of the rare
earth metals or possible complex compounds of the rare earth metals with diketones are, in
particular, those in which the organic group contained in the compound contains, in particular,
straight-chain or branched alkyl radicals having 1 to 20 carbon atoms, preferably 1 to 15 carbon
atoms, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, isopropyl, isobutyl, tert-butyl, 2-ethylhexyl,
neo-pentyl, neo-octyl, neo-decyl or neo-dodecyl.
[0035] Alcoholates of the rare earths which are mentioned are e.g.: neodymium(III) n-propanolate,
neodymium(III) n-butanolate, neodymium(III) n-decanolate, neodymium(III) iso-propanolate,
neodymium(III) 2-ethyl-hexanolate, praseodymium(III) n-propanolate, praseodymium(III) n-butanolate,
praseodymium(III) n-decanolate, praseodymium(III) isopropanolate, praseodymium(III) 2-ethylhexanolate, lanthanum(III) n-propanolate, lanthanum(III) n-butanolate, lanthanum(III) n-decanolate,
lanthanum(III) iso-propanolate and lanthanum(III) 2-ethyl-hexanolate, preferably neodymium(III) nbutanolate, neodymium(III) n-decanolate and neodymium(III) 2-ethyl-hexanolate.
[0036] Phosphonates, phosphinate and phosphates of the rare earths which are mentioned are e.g.:
neodymium(III) dibutylphosphonate, neodymium(III) dipentylphosphonate, neodymium(III)
dihexylphosphonate, neodymium(III) diheptylphosphonate, neodymium(III) dioctylphosphonate,
neodymium(III) dinonylphosphonate, neodymium(III) didodecylphosphonate, neodymium(III)
dibutylphosphinate, neodymium(III) dipentylphosphinate, neodymium(III) dihexylphosphinate,
neodymium(III) diheptylphosphinate, neodymium(III) dioctylphosphinate, neodymium(III)
dinonylphosphinate and neodymium(III) didodecylphosphinate, preferably neodymium(III)
dioctylphosphonate and neodymium(III) dioctylphosphinate.
[0037] Carboxylates of the rare earth metals which are suitable are: lanthanum(III) propionate,
lanthanum(III) diethylacetate, lanthanum(III) 2-ethylhexanoate, lanthanum(III) stearate, lanthanum(III)
benzoate, lanthanum(III) cyclohexanecarboxylate, lanthanum(III) oleate, lanthanum(III) versatate,
lanthanum(III) naphthenate, praseodymium(III) propionate, praseodymium(III) diethylacetate,
praseodymium(III) 2-ethylhexanoate, praseodymium(III) stearate, praseodymium(III) benzoate,
praseodymium(III) cyclohexanecarboxylate, praseodymium(III) oleate, praseodymium(III) versatate,
praseodymium(III) naphthenate, neodymium(III) propionate, neodymium(III) diethylacetate,
neodymium(III) 2-ethylhexanoate, neodymium(III) stearate, neodymium(III) benzoate, neodymium(III)
cyclohexanecarboxylate, neodymium(III) oleate, neodymium(III) versatate and neodymium(III)
naphthenate, preferably neodymium(III) 2-ethylhexanoate, neodymium(III) versatate and
neodymium(III) naphthenate. Neodymium versatate is preferred.
[0038] Complex compounds of the rare earth metals with diketones which may be mentioned are:
[0039] lanthanum(III) acetylacetonate, praseodymium(III) acetylacetonate and neodymium(III)
acetylacetonate, preferably neodymium(III) acetylacetonate.
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[0040] Addition compounds of the halides of the rare earth metals with an oxygen or nitrogen donor
compound which are mentioned are, for example:
[0041] lanthanum(III) chloride with tributyl phosphate, lanthanum(III) chloride with tetrahydrofuran,
lanthanum(III) chloride with iso-propanol, lanthanum(III) chloride with pyridine, lanthanum(III) chloride
with 2-ethylhexanol, lanthanum(III) chloride with ethanol, praseodymium(III) chloride with tributyl
phosphate, praseodymium(III) chloride with tetrahydrofuran, praseodymium(III) chloride with isopropanol, praseodymium(III) chloride with pyridine, praseodymium(III) chloride with 2-ethylhexanol,
praseodymium(III) chloride with ethanol, neodymium(III) chloride with tributyl phosphate,
neodymium(III) chloride with tetrahydrofuran, neodymium(III) chloride with iso-propanol,
neodymium(III) chloride with pyridine, neodymium(III) chloride with 2-ethylhexanol, neodymium(III)
chloride with ethanol, lanthanum(III) bromide with tributyl phosphate, lanthanum(III) bromide with
tetrahydrofuran, lanthanum(III) bromide with isopropanol, lanthanum(III) bromide with pyridine,
lanthanum(III) bromide with 2-ethylhexanol, lanthanum(III) bromide with ethanol, praseodymium(III)
bromide with tributyl phosphate, praseodymium(III) bromide with tetrahydrofuran, praseodymium(III)
bromide with isopropanol, praseodymium(III) bromide with pyridine, praseodymium(III) bromide with
2-ethylhexanol, praseodymium(III) bromide with ethanol, neodymium(III) bromide with tributyl
phosphate, neodymium(III) bromide with tetrahydrofuran, neodymium(III) bromide with isopropanol,
neodymium(III) bromide with pyridine, neodymium(III) bromide with 2-ethylhexanol and
neodymium(III) bromide with ethanol, preferably lanthanum(III) chloride with tributyl phosphate,
lanthanum(III) chloride with pyridine, lanthanum(III) chloride with 2-ethylhexanol, praseodymium(III)
chloride with tributyl phosphate, praseodymium(III) chloride with 2-ethylhexanol, neodymium(III)
chloride with tributyl phosphate, neodymium(III) chloride with tetrahydrofuran, neodymium(III)
chloride with 2-ethylhexanol, neodymium(III) chloride with pyridine, neodymium(III) chloride with 2ethylhexanol and neodymium(III) chloride with ethanol.
[0042] Possible allyl compounds of the rare earth metals (component (A)) are, in particular, those
which are chosen from the
[0043] tetra(allyl) complexes of the rare earths of the formula (I) [M(D)n][Ln(C3R5)4],
[0044] tris(allyl) complexes of the rare earths of the formula (II) Ln(C3R5)3(D)n,
[0045] bis(allyl) complexes of the rare earths of the formula (III) Ln(C3R5)2(X)(D)n and
[0046] mono(allyl) complexes of the rare earths of the formula (IV) Ln(C3R5)(X)2(D)n,
[0047] wherein
[0048] Ln denotes a trivalent element of the rare earths with the atomic numbers 21, 39 and 57 to 71,
[0049] X is identical or different and denotes an anion,
[0050] D is identical or different and denotes a neutral ligand,
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[0051] M represents an element of group la of the periodic table of the elements (PTE) [F. A. Cotton,
G. Wilkinson, Anorganische Chemie [Inorganic Chemistry], 4th edition, VCH Verlagsgesellschaft
mbH, Weinheim, 1985],
[0052] R is identical or different and represents hydrogen, represents a linear or branched, saturated
or mono- or polyunsaturated C1-C30-alkyl radical or C5-C30-cycloalkyl radical, which can optionally
contain one or more heteroatoms, such as N, P, O or S, represents a C6-C30-aryl radical which
optionally contains one or more heteroatoms and is optionally mono- or polysubstituted by alkyl,
alkinyl or alkenyl radicals having 1 to 30 C atoms or phenyl groups having 6 to 30 carbon atoms and
can be fused with other aromatic radicals containing 6 to 30 carbon atoms, or represents a silyl
group substituted by alkyl, alkenyl or alkinyl groups having 1 to 30 C atoms or phenyl groups having
6 to 30 C atoms,
[0053] n represents any desired number from 0 to 10, preferably 0 to 5.
[0054] Examples of compounds of the formula (I) to (IV) are [pi]-allyl complexes of a trivalent element
of the rare earths, such as e.g. the allyl compounds already described in WO 96/31544.
[0055] The following allyl compounds are particularly suitable: Nd(C3H5)3(O2C4H8), Nd(C3H5)3,
La(C3H5)3, C5Me5*La(C3H5)2, C5H5La(C3H5)2, C5Me5Nd(C3H5)2, C5H5Nd(C3H5)2,
La(C3H5)2Cl(THF)2, Nd(C3H5)2Cl(THF)2, La(C3H5)2Br(THF)2, La(C3H5)2I(THF)2,
La(C3H5)Cl2(THF)2, Nd(C3H5)Cl2(THF)2, La(C3H5)Br2(THF)3and Nd(C3H5)Br2(THF)2.
[0056] Neodymium versatate, neodymium octanoate and/or neodymium naphthenate are preferably
employed as compounds of the rare earth metals.
[0057] The above-mentioned compounds of the rare earth metals can be employed both individually
and as a mixture with one another.
[0058] Organoaluminum components (B) which are employed are compounds chosen from an
aluminum-trialkyl, a dialkylaluminum hydride and/or an alumoxane of the formulae (I)-(IV):
[0059] In the formulae (I) to (IV) of component (B), R can be identical or different and can denote
straight-chain and branched alkyl radicals having 1 to 10 C atoms, preferably 1 to 4 C atoms,
cycloalkyl radicals having 3 to 20 C atoms and aryl radicals having 6 to 20 C atoms and n can
denote 1 to 50.
[0060] Examples of suitable aluminum-alkyls of the formulae (i) and (II) are:
[0061] trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum tri-nbutylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum,
trioctylaluminum, diethylaluminum hydride, di-n-butylaluminum hydride and di-iso-butylaluminum
hydride. Triethylaluminum, triisobutylaluminum and di-iso-butylaluminum hydride are preferred.
177/425
[0062] Examples of alumoxanes (III) and (IV), which are mentioned are:
[0063] methylalumoxane, ethylalumoxane and iso-butylalumoxane, preferably methylalumoxane and
iso-butylalumoxane.
[0064] The aluminum-alkyls can be employed individually or as a mixture with one another.
[0065] So-called Lewis acids are employed as component (C). Examples which may be mentioned
are the organometallic halides in which the metal atom belongs to group 3a) or 4a), and halides of
elements of group 3a), 4a) and 5a) of the periodic table as described in "Handbook of Chemistry and
Physics", 45th Edition 1964-65.
[0066] Compounds, which are mentioned in particular are: methylaluminum dibromide,
methylaluminum dichloride, ethylaluminum dibromide, ethylaluminum dichloride, butylaluminum
dibromide, butylaluminum dichloride, dimethylaluminum bromide, dimethylaluminum chloride,
diethylaluminum bromide, diethylaluminum chloride, dibutylaluminum bromide, dibutylaluminum
chloride, methylaluminum sesquibromide, methylaluminum sesquichloride, ethylaluminum
sesquibromide, ethylaluminum sesquichloride, aluminum tribromide, antimony trichloride, antimony
pentachloride, silicon tetrachloride, methyltrichlorosilane, dimethyidichlorosilane,
trimethylchlorosilane, ethyltrichlorosilane, diethyldichlorosilane, triethylchlorosilane,
vinyltrichlorosilane, divinyidichlorosilane, trivinylchlorosilane, phosphorus trichloride, phosphorus
pentachloride and tin tetrachloride.
[0067] Diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride,
diethylaluminum bromide, ethylaluminum sesquibromide and/or ethylaluminum dibromide are
preferably employed.
[0068] The reaction products of aluminum compounds such as are described as component (B) with
halogens or halogen compounds, e.g. triethylaluminum with bromine or triethylaluminum with butyl
chloride, can also be employed as component (C). In this case, the reaction can be carried out
separately, or the amount of alkylaluminum compound required for the reaction is added to the
amount required as component (B).
[0069] Ethylaluminum sesquichloride, butyl chloride and butyl bromide are preferred.
[0070] If the alumoxanes (III) and (IV) are used as component (B), all or some of component (C) can
be dispensed with, as already mentioned above.
[0071] It is also possible, additionally, to add a further component (D) to the proven catalyst
components (A) to (C). This component (D) can be a conjugated diene, which can be the same
diene as is to be polymerized later with the catalyst. Butadiene and/or isoprene are preferably used.
[0072] If component (D) is added to the catalyst, the amount of (D) is preferably 1 to 1,000 mol per 1
mol of component (A), more preferably 1 to 100 mol. 1 to 50 mol, per 1 mol of component (A), of (D)
are preferably employed.
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[0073] In the preparation of the rubber solutions, the catalysts are employed in amounts of 1 [mu]mol
to 10 mmol, preferably 10 [mu]mol to 5 mmol, of the compound of the rare earth metals per 100 g of
the monomers.
[0074] It is, of course, also possible to employ the catalysts as any desired mixture with one another.
[0075] Conjugated dienes (diolefins) which can be employed in the process according to the
invention are e.g. 1,3-butadiene, 1,3-isoprene, 2,3-dimethylbutadiene, 2,4-hexadiene, 1,3-pentadiene
and/or 2-methyl-1,3-pentadiene, preferably 1,3-butadiene and/or 1,3-isoprene.
[0076] Polar monomers which can be employed in the process according to the invention are e.g.
compounds of the formula (V) to (XI)
[0077] In the formulae (V) to (XI), R can be identical or different and can denote hydrogen, straightchain and branched alkyl radicals having 1 to 10 C atoms, preferably 1 to 4 C atoms, cycloalkyl
radicals having 3 to 20 C atoms and aryl radicals having 6 to 20 C atoms, where alkyl radicals,
cycloalkyl radicals and aryl radicals can also contain heteroatoms, such as halogen, oxygen, sulfur
or nitrogen, and n can denote 1 to 10.
[0078] Compounds of the formula (V) to (XI) are, for example, lactones, such as caprolactone,
valerolactone and butyrolactone, lactams, such as caprolactam, valerolactam and butyrolactam,
thiolactams, such as thiocaprolactam, thiovalerolactam and thiobutyrolactam, epoxides, such as
ethylene oxide, propylene oxide, butene oxide, cyclohexene oxide, styrene oxide and
epichlorohydrin, cyclic sulfides, such as ethylene sulfide, propylene sulfide and styrene sulfide,
and/or cyclic carbonates, such as ethylene carbonate, propylene carbonate and neo-pentyl
carbonate. The lactones are preferably employed, and [epsilon]-caprolactone, [gamma]valerolactone, [delta]-valerolactone, [gamma]-butyrolactone and [beta]-butyrolactone are to be
mentioned as preferred.
[0079] Solvents which are employed for the process according to the present invention are inert,
aromatic, aliphatic or cycloaliphatic solvents. Suitable solvents are, for example, benzene, toluene,
pentane, n-hexane, iso-hexane, heptane and cyclohexane, or halogenated hydrocarbons, such as
e.g. methylene chloride and chlorobenzene. The solvents can also be employed as a mixture with
one another.
[0080] The process according to the present invention is preferably carried out at temperatures from
-20 to 200[deg.] C., preferably at 0 to 180[deg.] C., more preferably at 20 to 160[deg.] C.
[0081] The process according to the present invention can be carried out under normal pressure or
under increased pressure (0.1 to 12 bar).
179/425
[0082] The process according to the present invention can be carried out discontinuously, semicontinuously and continuously. In the continuous embodiment, it is to be ensured that the
polymerization zone of the conjugated dienes is separate from the polymerization zone of the polar
monomers and back-mixing of the polar monomers into the polymerization zone of the conjugated
dienes is avoided.
[0083] In an advantageous embodiment of the block copolymerization, the conjugated dienes are
polymerized up to a conversion of >=50% in a mixture with inert solvent by addition of the catalyst of
the rare earth metals while mixing in one or more continuously operated stirred tanks in cascade or in
a grafting flow reactor which effects mixing and/or a combination of the two reactor types. The active,
non-terminated polymer solution is led to a further polymerization reactor. The block copolymerization
is carried out in at least one further stage after addition of the polar monomer to the polydiene
solution, with mixing in one or more further continuously operated stirred tanks in cascade or in a
grafting flow reactor which effects mixing and/or a combination of the two reactor types. When the
desired conversion of polar monomers of >=30% has been reached, the catalyst can be deactivated
by addition of small amounts of, for example, water, carboxylic acids and/or alcohols and the block
polymer can be isolated by evaporation of the polymer solution, by precipitation with a non-solvent,
such as e.g. methanol, ethanol and acetone, or by steam distillation of the solvent. Additives, such as
stabilizers, anti-ageing agents and/or fillers, can be added during the polymerization and during the
isolation of the polymer.
[0084] It is of course possible for the block copolymer formed to be separated off from
homopolymers of the dienes and/or homopolymers of the polar monomers which may have been
formed. A suitable process for this separation is e.g. the method of demixing liquids [R. Kuhn,
Macromol. Chem., 1976,177,1525; 1980,181, 725].
[0085] The block copolymers obtained have an average molecular weight of 5,000 to 10g/mol. The
Tg values are <-90[deg.] C., preferably <-100[deg.] C.
[0086] The particular feature of the block copolymers is that polymers or polymer blocks which are
not miscible are coupled to one another by the block copolymer formation. However, the block
copolymers obtained here still have the properties of the corresponding individual polymers, for
example the same or similar melting and/or glass transition temperatures as occur in the
corresponding individual polymers. Due to the use of a non-polar diene and a polar monomer, the
block copolymers have an amphiphilic character which can be utilized for dispersing, imparting
phases or for coating applications. As a result of the possibility of choosing the ratio between the
various monomers in the block copolymer as desired, the polar or non-polar character of the block
copolymer can be accurately adjusted as desired.
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[0087] There are diverse possibilities for the use of the block copolymers. One field of use lies e.g. in
the preparation of vulcanizate mixtures with silica for tires and tire components. The block
copolymers can be employed as a substitute for the conventional coupling reagents (e.g. Si-69(R)
from Degussa AG) for binding silica fillers to the rubber matrix, where the polydiene part is bound to
the rubber matrix and the polymer part of the polar polymer is bound to the silica filler. However, a
pure mixture homogenization effect of the block copolymer without vulcanization is also conceivable.
The polar polymer part of the block copolymer can, furthermore, itself serve as a filler in a vulcanizate
mixture and can be bound to the rubber matrix via the polydiene part, or can merely be admixed.
[0088] It is, furthermore, possible to employ the block copolymers as thermoplastic elastomers, the
elastomer part being formed by the polymerized polydienes and the thermoplastic part being formed
by the polymerized polar monomers.
[0089] The block copolymers can moreover be used as a blending material for modification of
thermoplastics, for example for improving the impact strength. All thermoplastic materials are in
principle possible here, such as, for example, polycarbonates, polyvinyl halides (e.g. PVC),
polyamides, polyesters (e.g. PET, PBT), polyethers (e.g. polypropylene oxide, polyethylene oxide),
polyacrylates and derivatives thereof (e.g PMMA), polyvinyl acetate or polyoxymethylene.
EXAMPLES
[0090] All the polymerization reactions were carried out with exclusion of air and moisture in an inert
gas atmosphere using the Schlenk technique. Argon was used as the inert gas.
[0091] The solvents n-hexane and cyclohexane are predried over aluminum oxide/silica gel.
[epsilon]-Caprolactone was obtained from Aldrich, distilled before the polymerization and stored over
a molecular sieve 4 . Neodymium(III) versatate was employed as a 0.1 M solution in n-hexane.
DIBAH was purchased from Aldrich as a 0.1 M solution in a hexane fraction and employed in this
form. EASC was obtained as a pure substance from Witco. A 1.0 M EASC solution in n-hexane was
prepared from this. The technical-grade methanol used for precipitation of the polymer originated
from Kraemer & Martin GmbH. Bayer AG provided the stabilizer 2,2'-methylene-bis-(4-methyl-6-tertbutylphenol) (Vulkanoxe BKF).
[0092] The IR measurements were carried out on an IR spectrometer: BOMEM-Arid Zone(TM). The
polymers were swollen in carbon disulfide and then applied as thin films between two potassium
bromide plates and measured. The microstructure of the polybutadiene samples was determined as
described in the literature [M. Kraft in Struktur und Absorptionsspektroskopie der Kunststoffe
[Structure and Absorption Spectroscopy of Plastics], VCH, Weinheim, 1973, p. 93, E. 0. Schmalz, W.
Kimmer, Z. Anal. Chem. 1961,181, 229.].
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[0093] The polymer samples for the GPC were employed for the measurement as tetrahydrofuran
solutions with a concentration of 1 mg.ml. Before the measurement, the THF solutions were filtered
through a 0.2 [mu]m syringe filter. Calibration of the GPC was carried out with 1,4-polybutadiene
standards from Fluka. The 1,4-polybutadiene standards of weights 2,000, 5,000, 20,000, 30,000,
66,000, 160,000, 200,000, 300,000 and 800,000 g.molwere used for the calibration. GPC unit:
Thermo Separation(R) Products. Column set: 3* PL gel 10 p Mixed-B. RI detector: Shodex RI 74.
Eluent: THF; flow rate: 1.0 ml/min.
[0094] The conversions were determined gravimetrically; for this, the polymer solutions were
weighed after sampling (still with solvent and monomer) and after drying (at 65[deg.] C. in a vacuum
drying cabinet).
[0095] The polymers were separated in accordance with the principle of demixing liquids [R. Kuhn,
Macromol. Chem., 1976,177,1525; 1980,181, 725]. In a 500 ml three-necked flask with a precision
glass stirrer and reflux condenser, 1.0 to 1.2 g of polymer were heated under reflux for two hours with
the addition of approx. 1 mg of stabilizer (2,2'-methylene-bis(4-methyl-6-cyclohexylphenol)) in a
solvent mixture of 120 ml DMF and 180 ml MCH. The solution was transferred to centrifuge glasses
and centrifuged at a speed of 3,000 minfor 18 hours. The centrifugation was carried out at 60[deg.]
C. for the first hour and then at 25[deg.] C. The upper phase was then sucked off with a pipette and
the lower phase was separated off from the middle phase via the bottom opening of the centrifuge
glass. All the phases were transferred to separate glass flasks and the solvent was distilled off in
vacuo. The polymers which remained were dried in flasks overnight in a vacuum drying cabinet at
125[deg.] C. The individual percentage contents by weight in the phases could be determined by
weighing.
[0096] The NMR measurements were carried out on a nuclear magnetic resonance spectrometer
from Bruker, carrier frequency (H-NMR): 400.13 MHz, solvent CDCl3, standard: tetramethylsilane
([delta]=0.00 ppm), measurement temperature: 298 K.
[0097] Polymerization experiments:
[0098] Autoclave bottles: In-house production of Bayer AG, 200 ml thick-walled glass bottle with
metal attachment, Teflon seal and safety spring. 2 l glass autoclave: Buchi laboratory autoclave BEP
280 with U-shaped stirrer.
Examples 1 to 4
[0099] Polymerization Procedure (Autoclave):
[0100] Before the experiment, the autoclave (2 liter glass autoclave, Buchi laboratory autoclave BEP
280) was heated thoroughly in vacuo at 90[deg.] C. and secured. By applying a reduced pressure, 1
l of solvent was sucked into the autoclave under argon via a cannula. The autoclave was
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temperature-controlled at 60[deg.] C. The addition of 1,3-butadiene was then carried out via a
septum. The catalyst reagents neodymium(III) versatate (0.1 molar solution in hexane),
diisobutylaluminium hydride (0.1 molar solution in hexane) and ethylaluminium sesquichloride (1
molar solution in hexane) were then added. For the conversion/time measurement series, samples of
the reaction mixture were taken via a globe stop-cock at certain intervals of time. The reaction of
these samples was stopped with MeOH (+Vulkanox(R) BKF). The butadiene polymerization ran up to
high conversions; the polar comonomer ([epsilon]-caprolactone, methyl acrylate or vinyl propyl ether)
was then added. Further samples were then taken for the conversion/time determination. At the end
of the experiment, the residual of the reaction mixture remaining in the autoclave was poured into
methanol/Vulkanox(R) BKF and the polymerization was stopped in this manner. The polymer samples
taken were dried overnight at 65[deg.] C. in a vacuum drying cabinet.
TABLE 1
Examples 1 to 4
Example1234
Solventcyclohexanen-hexanen-hexanen-hexane
Solvent1000 ml 419 ml 436 ml 428 ml
Butadiene 190 g 47.7 g 44.4 g 46.6 g
Nd (versatate)3 0.4 mmol 0.17 mmol 0.17 mmol 0.17 mmol
DIBAH 8 mmol 8.5 mmol 5.1 mmol 1.7 mmol
EASC0.27 mmol 0.17 mmol 0.17 mmol 0.17 mmol
Butadiene polymerization
Temperature 60[deg.] C. 60[deg.] C. 60[deg.] C. 60[deg.] C.
Time 67 min 90 min 115 min 123 min
Butadiene 95% 100% 100% 100%
conversion
Block copolymerization
Active BR1190 g280.1 g267.7 g270.6 g
solution
Comonomer[epsilon]-[epsilon]-[epsilon]-[epsilon]caprolactonecaprolactonecaprolactonecaprolactone
Comonomer 182 g 51.5 g 51.5 g 51.5 g
Temperature 60[deg.] C. 60[deg.] C. 60[deg.] C. 60[deg.] C.
Time 118 min 80 min 128 min 110 min
Comonomer59.9% 100% 100% 100%
conversion
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Polymer (total) 289 g 92.9 g 87.6 g 90.3 g
Example 1
Separation of the Copolymer+Analysis:
[0101] The copolymer was separated by the method of demixing liquids, it being possible for the
block copolymer to be isolated at the phase boundary with a total weight content of 10 wt. % of the
total polymer in the case of the experiment with the polar monomer [epsilon]-caprolactone.
[0102] In the IR and in the H-NMR, the block copolymer isolated showed the signals of the two
polymerized monomers:
[0103] Poly([epsilon]-Caprolactone) Content in the Block Copolymer
[0104] IR: {tilde over ([upsilon])}=713 (w), 732 (w), 754 (w), 842 (w), 934 (w), 962 (w), 1048 (m), 1067
(w), 1108 (m), 1191 (s), 1244 (s), 1295 (m), 1367 (m), 1397 (w), 1420 (w), 1437 (w), 1471 (w), 1634
(w), 1726 (s), 2866 (m), 2944 (s).
[0105] H-NMR (CDCl3): [delta]=1.37 (m, 2H, 4-CH2), 1.65 (m, 4H, 3.5-CH2), 2.31 (t, JHH=7.5 Hz, 2H,
O-COCH2), 4.06 (t, JHH=6.7 Hz, 2H, COOCH2).
[0106] cis-1,4-Poly(Butadiene) Content in the Block Copolymer
[0107] IR: {tilde over ([upsilon])}=737 (s), 778 (w), 911 (w), 965 (w), 993 (m), 1019 (w), 1093 (w),
1161 (w), 1238 (w), 1260 (w), 1308 (m), 1402 (m), 1432 (s), 1451 (s), 1656 (s), 1738 (w), 2852 (s),
2938 (s), 3006 (s).
[0108] H-NMR (CDCl3):[delta]=2.08 (m, 4H, CH2), 5.38 (m, 2H, CH).
[0109] To rule out the possibility that only two homopolymers (polybutadiene and poly-[epsilon]caprolactone) are formed in the polymerization, after the separation with demixing liquids a GPC
analysis of the fractions obtained was carried out, this showing that the GPC signal of the block
copolymer is in the highest molecular weight range.
[0110] The average molecular weight was approx. 300,000 g/mol, the Tg value was -103[deg.] C.
The diene content was 30 wt. %, the content of polar monomers was 70 wt. %. The cis-1,4 content in
the diene block was 96%.
[0111] Further evidence of the formation of block copolymers was obtained from the morphology of
the polymer. For this, the block copolymer was analysed by transmission electron microscopy (TEM)
(FIG. 2) and the morphology thereof was compared with a cis-1,4-polybutadiene/poly-[epsilon]caprolactone blend which was prepared (FIG. 1). For this, 0.90 g poly-[epsilon]-caprolactone and
0.55 g cis-1,4-polybutadiene were dissolved in 1 l CHCl3 by stirring in a 2 l round-bottomed flask.
The polymer mixture was precipitated in 500 ml MeOH (+0.1 g Vulkanox(R) BKF) and then dried in a
vacuum drying cabinet at 50[deg.] C.
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Comparative Examples 5 to 7
[0112] Polymerization Procedure (Autoclave):
[0113] The polymerization was carried out analogously to Examples 1 to 4. The reaction quantities
and the results are summarized in Table 2.
TABLE 2
Comparative examples 5 to 7
Example567
Solventn-hexanecyclohexanecyclohexane
Solvent 434 ml1000 ml1000 ml
Butadiene 46.5 g 120 g 120 g
Nd (versatate)3 0.17 mmol 0.2 mmol
DIBAH 8.5 mmol 4 mmol 4 mmol
EASC 0.17 mmol
Butadiene polymerization
Temperature 60[deg.] C. 60[deg.] C. 60[deg.] C.
Time 120 min 83 min 260 min
Butadiene 100% 93% 99%
conversion
Block copolymerization
Active BR275.0 g1200 g1200 g
solution
Comonomeroctamethyl cyclo-methyl acrylatevinyl propyl ether
tetrasiloxane
Comonomer 72.1 g 190 g 200 g
Temperature 60[deg.] C. 60[deg.] C. 60[deg.] C.
Time 168 min 252 min 200 min
Comonomernot detectablenot detectablenot detectable
conversion
Polymer (total) 37.5 g 112 g 119 gClaims:
What is claimed is:
1. Block copolymers based on conjugated dienes and polar monomers, wherein the block
copolymers comprise the polymerized conjugated dienes in amounts of 5 to 95 wt. % and the
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polymerized polar monomers in amounts of 95 to 5 wt. %, the polymerized dienes having a cis-1,4
content of >=60 wt. %.
2. Block copolymers according to claim 1, wherein said conjugated dienes are selected from the
group consisting of 1,3-butadiene, 1,3-isoprene, 2,3-dimethylbutadiene, 2,4-hexadiene, 1,3pentadiene and/or 2-methyl-1,3-pentadiene.
3. Block copolymers according to claim 1, wherein said polar monomers are selected from the group
consisting of lactones, lactams, thiolactams, epoxides, cyclic sulfides and cyclic carbonates.
4. Block copolymers according to claim 3, wherein said polar monomers are selected from the group
consisting of [epsilon]-caprolactone, [gamma]-valerolactone, [delta]-valerolactone, [gamma]butyrolactone and/or [beta]-butyrolactone.
5. A process for the preparation of block copolymers based on conjugated dienes and polar
monomers, wherein the block copolymers comprise the polymerized conjugated dienes in amounts
of 5 to 95 wt. % and the polymerized polar monomers in amounts of 95 to 5 wt. %, the polymerized
dienes having a cis-1,4 content of >=60 wt. %. comprising the steps of
(i) polymerizing the conjugated dienes in the presence of catalysts comprising
(A) at least one compound of the rare earth metals,
(B) at least one organoaluminum compound and
(C) at least one Lewis acid
and in the presence of inert organic solvents up to a conversion of >=50 wt. %;
(ii) adding the polar monomers to the polymerization mixture and polymerization is carried out up to a
conversion of >=30 wt. % and
(iii) isolating the resulting block copolymer, and
(iv) employing the conjugated dienes in the reaction mixture in amounts of 5 to 30 wt. % and the
polar monomers in amounts of 1 to 30 wt. %.
6. The process according to claim 5, wherein said conjugated dienes are selected from the group
consisting of 1,3-butadiene, 1,3-isoprene, 2,3-dimethylbutadiene, 2,4-hexadiene, 1,3-pentadiene and
2-methyl-1,3-pentadiene.
7. The process according to claim 5, wherein said polar monomers are selected from the group
consisting of lactones, lactams, thiolactams, epoxides, cyclic sulfides and cyclic carbonates.
186/425
8. The process according to claim 7, wherein polar monomers are selected from the group
consisting of [epsilon]-caprolactone, [gamma]-valerolactone, [delta]-valerolactone, [gamma]butyrolactone and/or [beta]-butyrolactone.
9. The process according to claim 5, wherein the compounds of the rare earth metals which are
employed are their alcoholates, phosphonates, phosphinates, phosphates and carboxylates and the
complex compounds of the rare earth metals with diketones, the addition compounds of the halides
of the rare earth metals with an oxygen or nitrogen donor compound and allyl compounds of the rare
earth metals.
10. The process according to claim 9, wherein said compounds of the rare earth metals are selected
from the group consisting of neodymium versatate, neodymium octanoate and neodymium
naphthenate.
11. The process according to claim 5, wherein said organoaluminum compound is selected from the
group consisting of aluminumtrialkyl, dialkylaluminum hydride and alumoxanes.
12. The process according to claim 5, wherein said Lewis acid is organometallic halides of group IIIA
and IVA and/or halides of elements of group IIIA, IVA and VA of the periodic table.
13. The process according to claim 5, wherein said inert solvents are aliphatic or aromatic solvents.
14. The process according to claim 13, wherein said aliphatic solvents are selected from the group
consisting of butane, pentane, hexane or heptane or said aromatic solvents are selected from the
group consisting of benzene, toluene, ethylbenzene or dimethylbenzene or mixtures.
15. Vulcanizates with a filler content for the production of tires and tire components comprising block
copolymers based on conjugated dienes and polar monomers, wherein the block copolymers
comprise the polymerized conjugated dienes in amounts of 5 to 95 wt. % and the polymerized polar
monomers in amounts of 95 to 5 wt. %, the polymerized dienes having a cis-1,4 content of >=60
wt. %.
16. A thermoplastic elastomer containing block copolymers based on conjugated dienes and polar
monomers which comprise the polymerized conjugated dienes in amounts of 5 to 95 wt. % and the
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polymerized polar monomers in amounts of 95 to 5 wt. %, the polymerized dienes having a cis-1,4
content of >=60 wt. %.
17. A blend material for the modification of thermoplastics comprising block copolymers based on
conjugated dienes and polar monomers which comprise the polymerized conjugated dienes in
amounts of 5 to 95 wt. % and the polymerized polar monomers in amounts of 95 to 5 wt. %, the
polymerized dienes having a cis-1,4 content of >=60 wt. %.
188/425
20. JP2003183017 - 01.05.2003
PRECIPITATED SILICA WITH A HIGH BET/CTAB RATIO
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2003183017
Inventor(s):
BLUME ANKE [DE] (--); UHRLANDT STEFAN [DE] (--); SCHMOLL RALF [DE] (--);
LUGINSLAND DETLEF [DE] (--); THOMA HERBERT [DE] (--)
Applicant(s):
DEGUSSA [DE] (--)
IP Class 4 Digits: C08K; C08J; C08L; C01B
IP Class:
C8K3/34; C8L1/00; C8J3/00; C1B33/12
E Class: B60C1/00H; B60C1/00; C01B33/193; C08K3/36+L21/00; C09C1/30D4F
Application Number:
US20020247330 (20020920)
Priority Number: DE20011046325 (20010920)
Family: JP2003183017
Equivalent:
BR0203785; CA2403954; CN1408640; CZ20023146; DE10146325; EP1295850;
PL356090; TW574141; ZA200207506
Abstract:
THE PRESENT INVENTION RELATES TO A PRECIPITATED SILICA HAVING A PARTICULARLY HIGH
BET/CTAB RATIO, TO A PROCESS FOR PREPARING IT, AND TO ITS USE IN CLASTOMER
BLENDS.Description:
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a precipitated silica having a particularly high BET/CTAB ratio,
to a process for preparing it, and to its use.
[0003] 2. Description
189/425
[0004] The use of precipitated silicas in elastomer blends such as tires has been known for a long
time. Silicas used in tires are subject to stringent requirements. They should be amenable to easy
and thorough dispersion in the rubber, should connect well with the polymer chains present in the
rubber and with the other fillers, and should have a high abrasion resistance akin to that of carbon
black. Besides the dispersibility of the silica, therefore, the specific surface areas (BET or CTAB) and
the oil absorption capacity (DBP) are important. The specific surface areas are a measure of the
internal and external structure of the silica. Since these two methods use adsorbate molecules of
different size, the ratio of these two surface characteristics (i.e., the BET/CTAB surface area quotient)
provides an indication of the pore size distribution of the silica and of its ratio of "external" to "internal"
surface area. The surface properties of silicas are critical determinants of their possible application:
certain applications of a silica (e.g., carrier systems or fillers for elastomer blends) demand certain
surface properties.
[0005] Thus U.S. Pat. No. 6,013,234 discloses the preparation of the precipitated silica having a BET
and CTAB surface area of in each case from 100 to 350 m/g. This silica is particularly suitable for
incorporation into elastomer blends, with the BET/CTAB ratios being between 1 and 1.5. EP 0 937
755 discloses various precipitated silicas which possess a BET surface area of from about 180 to
about 430 m/g and a CTAB surface area of from about 160 to 340 mg. These silicas are particularly
suitable as carrier material and have a BET to CTAB ratio of from 1.1 to 1.3. EP 0 647 591 discloses a
precipitated silica which has a ratio of BET to CTAB surface area of from 0.8 to 1.1, it being possible
for these surface characteristics to adopt absolute values of up to 350 m/g. EP 0 643 015 presents a
precipitated silica which can be used as an abrasive component and/or thickening component in
toothpastes and which has a BET surface area of from 10 to 130 m/g and a CTAB surface area of
from 10 to 70 m/g, i.e., a BET to CTAB ratio of from about 1 to 5.21.
SUMMARY OF THE INVENTION
[0006] It has now been found that a precipitated silica which has very different BET and CTAB
surface areas while remaining above minimum values for these parameters is especially suitable as a
filler in elastomer blends.
[0007] The present invention accordingly provides precipitated silicas whose BET surface area is
more than 135 m/g and whose CTAB surface area is more than 75 m /g, the ratio of the BET to the
CTAB surface areas being >=1.7, and a process for producing the same. In addition, the present
invention provides for a vulcanizable rubber mixture or vulcanizate, and a tire comprising the
precipitated silica described above.
190/425
[0008] A more complete appreciation of the invention and many of the attendant advantages thereof
will be readily obtained as the same becomes better understood by reference to the following
detailed description when considered with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows the RPA plots of the silica of the invention (KS) in comparison with the standard
silica Ultrasil VN2 GR.
[0010] FIG. 2 is a diagram of the values needed to calculate the wk coefficient.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] The precipitated silicas of the invention may have a maximum BET surface area of 600 m/g
and/or a maximum CTAB surface area of 350 m/g. Furthermore, the precipitated silicas may be
characterized by a DBP absorption of 100-350 g/100 g, by a wk coefficient of <=3.4 (ratio of the
peak height of the particles undegradable by ultrasound, in the size range 1.0-100 [mu]m, to the
peak height of the degraded particles in the size range <1.0 [mu]m), and/or by a Sears number of 525 ml.
[0012] The ratio of BET/CTAB surface area of the precipitated silica of the invention is preferably
situated within the following ranges:
BETCTABBET/CTAB
[m/g][m/g]ratio
140801.75
1801001.8
2151131.90
2501252
2921292.26
3001003
3361432.35
3441682.05
3502001.75
4001502.67
4502002.25
5002801.79
5502801.96
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6002003
[0013] The present invention further provides a process for preparing a precipitated silica having a
[0014] BET surface area>=135 m/g and a
[0015] CTAB surface area 24 75 m/g
[0016] with a BET/CTAB surface area ratio>=1.7, by
[0017] a) initially introducing an aqueous waterglass solution,
[0018] b) metering waterglass and sulfuric acid simultaneously into this initial charge at 55-95[deg.]
C. for 10-60 minutes with stirring,
[0019] c) halting the metered addition for 30-90 minutes while maintaining the temperature,
[0020] d) metering in waterglass and sulfuric acid simultaneously at the same temperature for 20-80
minutes with stirring,
[0021] e) acidifying to a pH of about 3.5 with sulfuric acid, and
[0022] f) filtering and drying the product.
[0023] The components supplied in steps b) and d) may each have identical or different
concentrations and/or flow rates. In one process variant, the concentration of the components used
is the same in both steps but the flow rate of the components in step d) is 125-140% of the flow rate
in step b).
[0024] Besides waterglass (sodium silicate solution) it is also possible to use other silicates such as
potassium silicate or calcium silicate. In place of sulfuric acid it is also possible to use other acidifiers
such as HCl, HNO3 or CO2.
[0025] The physicochemical data of the precipitated silicas of the invention are determined by the
following methods:
BET surface areaAreameter from Strцhlein, in accordance with
ISO 5794/Annex D
CTAB surface areaat pH 9, in accordance with Janzen and Kraus in
Rubber Chemistry and Technology 44(1971) 1287
DBP numberASTM 2414-88
[0026] The filtration and drying of the silicas of the invention are familiar to the skilled worker and may
be read about, for example, in the abovementioned patents. The precipitated silica is preferably
dried by spray drying (in a nozzle tower) or by means of a rack drier, a flash drier or a spin-flash drier.
Spray drying may be conducted in accordance, for example, with U.S. Pat. No. 4,097,771. Here, in a
nozzle tower drier, a precipitated silica is produced which is obtained in particle form with an
average diameter of more than 80 [mu]m, in particular more than 90 [mu]m, with particular
preference more than 200 [mu]m.
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[0027] The silicas of the invention may therefore be used as fillers in elastomer blends, in particular
for tires.
[0028] Moreover, the silicas of the invention may be used in all fields of application in which it is
common to use silicas, such as, for example, in battery separators, antiblocking agents, flatting
agents in paints, paper coatings or defoamers.
[0029] The invention further provides elastomer blends, vulcanizable rubber mixtures or other
vulcanizates, and also tires, which comprise the silica of the invention.
[0030] Optionally, the silica of the invention may be modified with silanes or organosilanes of the
formulae I to III.
[Rn-(RO)3-nSi-(Alk)m-(Ar)p]q[B] (I),
Rn-(RO)3-nSi-(Alkyl) (II),
[0031] or
Rn(RO)3-nSi-(Alkenyl) (III),
[0032] wherein
[0033] B is -SCN, -SH, -Cl, -NH2 (if q=1) or -Sx- (if q=2);
[0034] R and Rare an alkyl group having 1 to 4 carbon atoms or the phenyl radical, it being possible
for all radicals R and Rto have in each case the same meaning or a different meaning;
[0035] R is a C1-C4 alkyl or C1-C4 alkoxy group;
[0036] n is 0, 1 or 2;
[0037] Alk is a divalent unbranched or branched hydrocarbon radical having from 1 to 6 carbon
atoms,
[0038] m is 0 or 1,
[0039] Ar is an arylene radical having from 6 to 12 carbon atoms, preferably 6 carbon atoms,
[0040] p is 0 or 1 with the proviso that p and n are not both 0,
[0041] x is a number from 2 to 8,
[0042] Alkyl is a monovalent unbranched or branched saturated hydrocarbon radical having from 1
to 20 carbon atoms, preferably from 2 to 8 carbon atoms; and
[0043] Alkenyl is a monovalent unbranched or branched unsaturated hydrocarbon radical having
from 2 to 20 carbon atoms, preferably from 2 to 8 carbon atoms.
[0044] The modification of the precipitated silica with organosilanes may take place in mixtures of
from 0.5 to 50 parts, based on 100 parts of precipitated silica, in particular from 1 to 15 parts, based
on 100 parts of precipitated silica, with the reaction between precipitated silica and organosilane
being carried out during the preparation of the mixture (in situ) or externally by spray application and
subsequent thermal conditioning of the mixture or by mixing the silane and the silica suspension with
subsequent drying and thermal conditioning. This range for the modification of the precipitated silica
193/425
with organosilanes includes all specific values and subranges therebetween, such as 5, 10, 20, 25,
30, 35, 40 and 45 parts, based on 100 parts of precipitated silica.
[0045] In one preferred embodiment of the invention, bis(triethoxysilylpropyl)-tetrasulfane can be
used as silane.
[0046] The silica of the invention may be incorporated into elastomer blends, tires or vulcanizable
rubber mixtures as a reinforcing filler in amounts of from 5 to 200 parts, based on 100 parts of rubber,
in the form of powders, microbeads or granules, both with silane modification and without silane
modification. This range for the incorporation into elastomer blends, tires or vulcanizable rubber
mixtures as a reinforcing filler includes all specific values and subranges therebetween, such as 10,
20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, and 190 parts, based on
100 parts of rubber.
[0047] The addition of one or more of the abovementioned silanes may take place together with the
silicas of the invention to the elastomer, with the reaction between filler and silane taking place during
the mixing process at elevated temperatures (in situ modification) or in already pre-modified form (for
example, DE-C 40 04 781); that is, the two reactants are reacted outside of the actual preparation of
the mixture.
[0048] In addition to blends which include exclusively the silicas of the invention, with and without
organosilanes of formulae I to III as fillers, the elastomers may further be filled with one or more fillers
having a greater or lesser reinforcing action. Primarily it would be customary here to have a blend of
carbon black (for example, furnace blacks, gas blacks, lamp blacks, acetylene blacks) and the
silicas of the invention, with and without silane, but also between natural fillers, such as clay,
siliceous chalk, further commercial silicas, and the silicas of the invention.
[0049] Here too, as for the amount of the organosilanes, the blending ratio is guided by the target
profile of properties of the finished rubber mixture. A ratio of 5-95% between the silicas of the
invention and the other abovementioned fillers is conceivable and is also realized in this context.
[0050] Besides the silicas of the invention, the organosilanes, and the other fillers, the elastomers
constitute a further important constituent of the rubber mixture. The silicas of the invention may be
used in all types of rubber which can be crosslinked with accelerator/sulfur or else with peroxide.
Mention may be made in this context of elastomers, natural and synthetic, oil-extended or otherwise,
as individual polymers or as blends with other rubbers, such as natural rubbers, butadiene rubbers,
isoprene rubbers, butadiene-styrene rubbers, especially SBR, prepared by means of the solution
polymerization process, butadiene-acrylonitrile rubbers, butyl rubbers and terpolymers of ethylene,
propylene and nonconjugated dienes. For mixtures with the aforementioned rubbers, the following
additional rubbers are also suitable:
194/425
[0051] carboxyl rubbers, epoxy rubbers, trans-polypentenamers, halogenated butyl rubbers, 2chlorobutadiene rubbers, ethylene-vinyl acetate copolymers, ethylene-propylene copolymers, and,
where appropriate, chemical derivatives of natural rubber, and also modified natural rubbers.
[0052] Likewise known are the customary further constituents such as plasticizers, stabilizers,
activators, pigments, aging inhibitors, and processing auxiliaries, in the customary amounts.
[0053] The silicas of the invention, with and without silane, find application in all rubber applications,
such as tires, conveyor belts, seals, V-belts, hoses, soles, etc.
[0054] The invention additionally provides elastomer blends, particularly vulcanizable rubber
mixtures, which contain the silicas of the invention in amounts of from 5 to 200 parts, based on 100
parts of elastomer or rubber. The incorporation of this silica and the preparation of the mixtures
comprising this silica take place in the manner customary in the rubber industry, on an internal mixer
or roll unit. The presentation form or use form may be that of a powder, of microbeads or of granules.
In this respect too, the silicas of the invention do not differ from the known pale silicate fillers.
[0055] In order to obtain a good profile of values in a polymer mixture, the dispersion of the
precipitated silica in the matrix, the polymer, is of critical importance.
[0056] It has been found that the wk coefficient is a measure of the dispersibility of a precipitated
silica.
[0057] The wk coefficient is determined as follows:
[0058] The measurement is based on the principle of laser diffraction. Measurement is carried out
using a Coulter LS 230.
[0059] To determine the coefficient, 1.3 g of the precipitated silica are introduced into 25 ml of water
and the mixture is treated with ultrasound at 100 W (90% pulsed) for 4.5 minutes. The solution is then
transferred to the measuring cell and treated with ultrasound for a further minute.
[0060] Detection by means of two laser diodes situated at different angles to the sample is carried
out during the ultrasound treatment. According to the principle of the diffraction of light, the laser
beams are diffracted. The resulting diffraction pattern is analyzed with computer assistance. The
method allows the particle size distribution to be determined over a relatively wide measurement
range (approximately 40 nm-500 [mu]m).
[0061] An essential point here is that the introduction of energy by ultrasound represents a simulation
of the input of energy by mechanical forces in industrial mixing units in the tire industry.
[0062] FIG. 2 is a diagram of the values needed to calculate the wk coefficient.
[0063] The plots show a first maximum in the particle size distribution in the region of 1.0-100 [mu]m
and a further maximum in the region <1.0 [mu]m. The peak in the region 1.0-100 [mu]m indicates the
fraction of uncomminuted silica particles following the ultrasound treatment. These decidedly coarse
particles are poorly dispersed in the rubber mixtures. The second peak, with markedly smaller
195/425
particle sizes (<1.0 [mu]m), indicates the silica particle fraction which has been comminuted during
the ultrasound treatment. These very small particles are dispersed excellently in rubber mixtures.
[0064] The wk coefficient, then, is a ratio of the peak height of the undegradable particles (B) whose
maximum is situated in the range 1.0-100 [mu]m (B') to the peak height of the degraded particles (A)
whose maximum is situated in the range <1.0 [mu]m (A').
[0065] The wk coefficient is hence a measure of the "degradability" (i.e., dispersibility) of the
precipitated silica. It holds that the smaller the wk coefficient, the easier it is to disperse a
precipitated silica, i.e., the greater the number of particles degraded in the course of incorporation
into rubber.
[0066] The silicas of the invention have wk coefficients<3.4. The maximum in the particle size
distribution of the undegradable particles of the precipitated silica of the invention is situated in the
range 1.0-100 [mu]m. The maximum in the particle size distribution of the degraded particles of the
precipitated silica of the invention is situated in the range<1.0 [mu]m. Known precipitated silicas
have much higher wk coefficients and different maxima in the particle size distributions measured
with the Coulter LS 230, and are therefore more difficult to disperse.
[0067] The examples which follow are intended to illustrate the invention without restricting its scope.
[0068] Having generally described the invention, a further understanding can be obtained by
reference to certain specific examples which are provided herein for purposes of illustration only and
are not intended to be limiting unless otherwise specified.
EXAMPLES
Example 1
[0069] A reactor is charged with 40 l of water and with 4.3 liters of waterglass (density 1.348, 27.0%
SiO2, 8.05% Na2O). Thereafter, 8.6 l/h waterglass and 1.6 l/h sulfuric acid (96%, density 1.400) are
metered in at 75[deg.] C. for 35 minutes. After 35 minutes, the addition is interrupted for 60 minutes
and then recommenced, this time metering in 11.9 l/h waterglass and 2.3 l/h sulfuric acid of the
grade indicated above for 50 minutes. The addition of waterglass is then stopped and the sulfuric
acid is continued until a pH of about 3.5 has been reached. The resulting product is filtered as usual
and then subjected to quick drying. The product obtained has a BET surface area of 215 m/g and a
CTAB surface area of 113 m/g.
Example 2
[0070] The formulation used for the rubber mixtures is shown in Table 1 below. The unit phr denotes
parts by weight per 100 parts of the crude rubber used. The general process for preparing rubber
196/425
mixtures and their vulcanizates is described in the following text: "Rubber Technology Handbook", W.
Hofmann, Hanser Verlag 1994.
TABLE 1
ReferenceExample
Substance[phr][phr]
Stage 1
Buna VSL 5025-19696
Buna CB 243030
Ultrasil 7000 GR80Silica of the invention80
ZnO33
Stearic acid22
Naftolene ZD1010
Vulkanox 40201.51.5
Protector G35P11
X 50-S12.812.8
Stage 2
Batch Stage 1
Stage 3
Batch Stage 2
Vulkacit D22
Perkacit TBzTD0.20.2
Vulkacit CZ1.51.5
Sulfur1.51.5
[0071] The polymer VSL 5025-1 is a solution-polymerized SBR copolymer from Bayer AG having a
styrene content of 25% by weight and a butadiene content of 75% by weight. Of the butadiene, 73%
is 1,2, 10% is cis-1,4 and 17% is trans-1,4 linked. The copolymer contains 37.5 phr oil and has a
Mooney viscosity (ML 1+4/100[deg.] C.) of 50+-4.
[0072] The polymer Buna CB 24 is a cis-1,4 polybutadiene from Bayer AG having a cis-1,4 content of
97%, a trans-1,4 content of 2%, a 1,2 content of 1%, and a Mooney viscosity of 44+-5.
[0073] The aromatic oil used was Naftolen ZD from Chemetall; Vulkanox 4020 is 6PPD from Bayer
AG and Protektor G35P is an ozone protection wax from HB Fuller GmbH. Vulkacit D (DPG) and
Vulkacit CZ (CBS) are commercial products from Bayer AG. Perkacit TBzTD is available from Flexsys.
197/425
[0074] The coupling reagent X50-D is a {fraction (50/50)}blend of Si 69 from Degussa AG and carbon
black N 330. Ultrasil 7000 GR is an easily dispersible precipitated silica from Degussa AG having a
BET surface area of 170 m/g.
[0075] The rubber mixtures were prepared in accordance with the mixing instructions shown in Table
2.
TABLE 2
Settings
Mixing unitWerner & Pfleiderer N type
Rotary speed70 min
Ram pressure5.5 bar
Empty volume1.6 L
Fill level0.73
Flow temperature70[deg.] C.
Mixing operation
0 to 1 minBUNA VSL 5025-1 + Buna CB 24
1 to 3 min[1/2] silica, X50-S
3 to 5 min[1/2] silica, remainder of Stage 1 chemicals
4 minClean
4 to 5 minMix and discharge
Batch temperature145-150[deg.]
Storage24 h at room temperature
Stage 2
Settings
MixerAs in Stage 1 except for:
Rotary speed80 min
Flow temperature80[deg.] C.
Fill level0.70
Mixing operation
0 to 2 minBreak open Stage 1 batch
2 to 5 minMaintain batch temperature of 150[deg.] C. by speed
5 minvariation Discharge
150[deg.] C.
Batch temperature24 h at room temperature
Storage
Stage 3
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Settings
MixerAs in Stage 1 except for:
Rotary speed40 min
Fill level0.69
Flow temperature50[deg.] C.
Mixing operation
0 to 2 minBatch Stage 2, accelerator, sulfur
2 minDischarge and form sheet on laboratory mixing roll
unit (diameter 200 mm, length 450 mm, flow
temperature 50[deg.] C.)
Homogenizing:
cut in 3* left, 3* right and fold over, and tumble for
10* with a wide roll nip (3.5 mm)
Pull out sheet
Batch temperature85-95[deg.] C.
[0076] In Table 3, the methods for rubber testing are compiled.
TABLE 3
Physical TestingStandard/Conditions
ML 1 + 4, 100[deg.] C., Stage 3DIN 53523/3, ISO 667
Vulkameter testing, 165[deg.] C.DIN 53529/3, ISO 6502
Dmax - Dmin [dNm]
t10% and t90% [min]
Tensile test on ring, 23[deg.] C.DIN 53504, ISO 37
Strain values [MPa]
Elongation at break [%]
Shore A hardness, 23[deg.] C. [SH]DIN 53 505
Viscoelastic properties,DIN 53 513, ISO 2856
0 and 60[deg.] C., 16 Hz, 50 N initial force
and 25 N amplitude force
Storage modulus E* [MPa]
Loss factor tan [delta] []
Goodrich Flexometer, heat buildupDIN 53533, ASTM D 623 A
25 min, 0.25 inch stroke
Internal temperature [[deg.] C.]
Permanent Set [%]
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Ball rebound, 23[deg.] C., 60[deg.] C. [%]ASTM D 5308
DIN abrasion, 10 N force [mm]DIN 53516
[0077] The results of rubber industry testing of the reference mixture with Ultrasil 7000 GR and the
silica of the invention according to Example 1 are shown comparatively in Table 4.
TABLE 4
Results of rubber industry testing
Ref.Exp.
ML 1 + 4[ME]6367
Dmax-Dmin[dNm]18.417.5
t10%[min]1.32.2
t90%[min]6.25.6
t90%-t10%[min]4.93.4
Shore A hardness[SH]6766
Strain value 100%[MPa]2.12.9
Strain value 300%[MPa]10.311.8
Elongation at break[%]390320
DIN abrasion[mm]7785
Ball rebound 60[deg.] C.[%]54.964.8
Heat buildup[[deg.] C.]11190
Permanent set[%]5.91.9
E* (0[deg.] C.)[MPa]25.416.9
tan [delta] (0[deg.] C.)[]0.4710.396
E* (60[deg.] C.)[MPa]8.98.5
tan [delta] (60[deg.] C.)[]0.1280.095
[0078] As can be seen from the data in Table 1, the ML 1+4 viscosities of the two mixtures are at a
comparable level despite the highly different CTAB surface areas, which suggests good
processability of the silica of the invention.
[0079] The scorch time t 10% is advantageously extended for the mixture of the example, and the
crosslinking rate t 90%-t 10% is increased.
[0080] Furthermore, the mixture of the example features higher strain values at similar Shore A
hardness, despite the fact that the CTAB surface area of the silica of the invention is much lower than
that of Ultrasil 7000 GR. The skilled worker is aware that only an increase in the CTAB surface area of
the silica leads already to higher viscosities and Shore A hardnesses. Accordingly, the silica of the
invention with the high BET/CTAB surface area ratio possesses an excellent reinforcing behavior.
200/425
[0081] From the dynamic data, distinct advantages of the silica of the invention can be seen in terms
of the hysteresis loss. As compared with the reference mixture, the ball rebound at 60[deg.] C. is
increased in the mixture of the example, the heat buildup in the Goodrich flexometer is lowered, and
the tan [delta] at 60[deg.] C. as well is advantageously lowered, suggesting a reduced rolling
resistance in a tire tread mixture.
[0082] In Examples 3 and 4, the following substances were used:
Krynol 1712styrene-butadiene rubber based on emulsion
polymerization
Buna VSL 5025-0styrene-butadiene rubber based on solution
polymerization
Buna CB 10butadiene rubber
SMR 10natural rubber, ML(1 + 4) = 60-70
X 50 S50:50 blend of Si 69/bis(3triethoxysilylpropyl)tetrasulfane
Corax N 375standard carbon black
ZnO RSzinc oxide
Stearic acid
Naftolenaromatic oil
Protektor G35Pozone protection wax
Lipoxol 4000polyethylene glycol
Vulkanox 4020N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine
Vulkanox HS/LG2,2,4-trimethyl-1,2-dihydroquinoline, oligomerized
DPGdiphenylguanidine
CBSN-cyclohexyl-2-benzothiazylsulfenamide
ZBECzinc dibenzyldithiocarbamate
Sulfur
Example 3
[0083] Precipitated silica of the invention in comparison with the standard silica Ultrasil VN2 GR
(Degussa AG) in a straight E-SBR mixture (amounts in phr):
Silica of
VN2Example 1
Krynol 1712137.5137.5
Ultrasil VN2 GR50Silica of the invention-50
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X 50 S33
ZnO RS33
Stearic acid11
Vulkanox 402022
Lipoxol 40001.51.5
DPG1.51.5
CBS1.51.5
Sulfur2.22.2
Vulcanizate data: 160[deg.] C.4.74.4
t90-t10 [%]
100% modulus [MPa]1.11.5
300% modulus [MPa]4.85.8
E* 60[deg.] C.5.46.2
tan [delta] 60[deg.] C.0.0850.085
E* 0[deg.] C.7.98.9
Dispersion, peak area topography3.92.0
Dispersion, number of peaks 2-5 [mu]m3226
Wet slippage LAT 100 rating [%]100106
(mean values of the temperature evaluation)
[0084] FIG. 1 shows the RPA plots of the silica of the invention (KS) in comparison with the standard
silica Ultrasil VN2 GR.
[0085] As compared with the standard silica Ultrasil VN2 GR, the silica of the invention leads to
higher moduli values, higher E* values, and a markedly improved dispersion (corresponding to better
abrasion characteristics). In the RPA plots shown in FIG. 1, it is evident that the use of the silica of the
invention leads both to a higher filler-filler network and to a markedly higher filler-polymer interaction,
which means that the silica of the invention exhibits a considerably better reinforcing behavior.
Furthermore, the use of the silica of the invention displays greatly improved wet slippage as
compared with the standard silica Ultrasil VN2 GR.
Example 4
[0086] Precipitated silica of the invention as compared with the standard silica Ultrasil VN2 GR in a
winter tire mixture (amounts in phr):
12
Buna VSL 5025-04040
Buna CB 104545
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SMR 101515
Ultrasil VN2 GR70Silica of the invention-70
X 50 S66
Corax N 3752020
ZnO RS33
Stearic acid22
Vulkanox 402011
Naftolen ZD3535
Protektor G35P1.51.5
Vulkanox HS/LG11
DPG1.71.7
CBS1.71.7
ZBEC0.10.1
Sulfur1.41.4
Vulcanizate data: 160[deg.] C.6.56.9
t90 [%]
100% modulus [MPa]1.72.2
300% modulus [MPa]7.58.1
Shore hardness6464
E* 60[deg.] C.9.39.8
tan [delta] 60[deg.] C.0.2010.188
1/E* -20[deg.] C.1.52.3
tan [delta] -20[deg.] C.0.4260.474
Dispersion, peak area topography1.21.8
Permanent set [%]13.810.9
Heat buildup [[deg.] C.]154145
[0087] As compared with the standard silica Ultrasil VN2 GR, the silica of the invention leads to
higher moduli values, to a lower heat buildup (corresponding to a longer lifetime), to equally good
dispersion values, to higher E* values, to a lower tan[delta] 60[deg.] C. (corresponding to improved
rolling resistance), and to a higher 1/E* at -20[deg.] C. (compliance), corresponding to improved grip
on snow.
Example 5
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[0088] A reactor is charged with 40 l of water and with 4.6 l of waterglass (density 1.348, 27.0% SiO2,
8.05% Na2O). Thereafter, 8.7 l/h waterglass and 1.7 l/h sulfuric acid (96%, density 1.400) are
metered in at 70[deg.] C. for 35 minutes. After 35 minutes, the addition is interrupted for 60 minutes
and then recommenced, this time metering in 11.9 l/h waterglass and 2.4 l/h sulfuric acid of the
grade indicated above for 50 minutes. The addition of waterglass is then stopped and the sulfuric
acid is continued until a pH of about 3.5 has been reached. The resulting product is filtered as usual
and then subjected to quick drying. The product obtained has a BET surface area of 292 m/g and a
CTAB surface area of 129 m/g.
[0089] The BET/CTAB ratio is 2.26.
Example 6
[0090] As Example 5, with the temperature being 65[deg.] C. The product obtained has a BET
surface area of 336 m/g and a CTAB surface area of 143 m/g.
[0091] The BET/CTAB ratio is 2.35.
Example 7
[0092] As Example 5, with the temperature being 60[deg.] C. The product obtained has a BET
surface area of 344 m/g and a CTAB surface area of 168 m/g.
[0093] The BET/CTAB ratio is 2.05.
[0094] Obviously, numerous modifications and variations of the present invention are possible in light
of the above teachings. It is therefore to be understood that within the scope of the appended claims,
the invention may be practiced otherwise than as specifically described herein.
[0095] Each document, patent application or patent publication cited by or referred to in this
disclosure is incorporated by reference in its entirety. Specifically, priority application DE 10146325.1,
filed Sep. 20, 2001, is hereby incorporated by reference.Claims:
What is claimed is:
1. A precipitated silica having a
BET surface area>=135 m/g
CTAB surface area>=75 m/g
wherein the BET/CTAB surface area ratio is >=1.7.
2. The precipitated silica as claimed in claim 1, wherein said BET surface area is at most 600 m/g.
3. The precipitated silica as claimed in claim 1, wherein said CTAB surface area is at most 350 m/g.
204/425
4. The precipitated silica as claimed in claim 1, having a DBP absorption of 100-350 g/100 g.
5. The precipitated silica as claimed in claim 1, having a wk coefficient of <=3.4, wherein said wk
coefficient is a ratio of the peak height of the particles undegradable by ultrasound in the size range
1.0-100 [mu]m to the peak height of the degraded particles in the size range <1.0 [mu]m.
6. The precipitated silica as claimed in claim 1, having a surface which has been modified with at
least one organosilane of the formula I, II or III
[Rn-(RO)3-nSi-(Alk)m-(Ar)p]q[B] (I)Rn-(RO)3-nSi-(Alkyl) (II)Rn-(RO)3-nSi-(Alkenyl) (III)
Bis -SCN, -SH, -Cl, -NH2 (if q = 1) or -Sx- (if
q = 2);
R and Rare an alkyl group having 1 to 4 carbon atoms
or the phenyl radical, it being possible for all
radicals R and R to have in each case the
same meaning or a different meaning;
Ris a C1-C4 alkyl or C1-C4 alkoxy group;
nis 0, 1 or 2;
Alkis a divalent unbranched or branched
hydrocarbon radical having from 1 to 6
carbon atoms,
mis 0 or 1,
Aris an arylene radical having from 6 to 12
carbon atoms, preferably 6 carbon atoms,
pis 0 or 1 with the proviso that p and n are not
both 0,
xis a number from 2 to 8,
Alkylis a monovalent unbranched or branched
saturated hydrocarbon radical having from 1
to 20 carbon atoms, preferably from 2 to 8
carbon atoms;
Alkenylis a monovalent unbranched or branched
unsaturated hydrocarbon radical having from
2 to 20 carbon atoms, preferably from 2 to 8
carbon atoms; and
205/425
qis 1 or 2.
7. The precipitated silica as claimed in claim 1, having an average particle diameter of more than 80
[mu]m.
8. A process for preparing a precipitated silica, comprising:
a) forming an aqueous waterglass solution,
b) metering waterglass and sulfuric acid simultaneously into said aqueous waterglass solution at a
temperature of 55-95[deg.] C. for 10-60 minutes with stirring,
c) halting said metering for 30-90 minutes while maintaining said temperature of 55-95[deg.] C.,
d) metering in waterglass and sulfuric acid simultaneously into said aqueous waterglass solution at
said temperature of 55-95[deg.] C. for 20-80 minutes with stirring to form a silica suspension,
e) acidifying to a pH of about 3.5 with sulfuric acid, and
f) filtering and drying said precipitated silica,
wherein said precipitated silica has BET surface area >=135 m/g, CTAB surface area >=75 m/g, and
BET/CTAB surface area ratio >=1.7.
9. The process as claimed in claim 8, wherein said waterglass and sulfuric acid supplied in steps b)
and d) each have an identical or a different concentration.
10. The process as claimed in claim 8, wherein said waterglass and sulfuric acid supplied in steps b)
and d) each have an identical or a different feed rate.
11. The process as claimed in claim 10, wherein steps b) and d) have an equal concentration of said
waterglass and sulfuric acid in and step d) has a feed rate of 125-140% of the feed rate in step b).
12. The process as claimed in claim 8, wherein said drying is carried out using a spray drier, rack
drier, flash drier or spin-flash drier.
13. The process as claimed in claim 8, further comprising granulating said precipitated silica with a
roll compactor after said drying.
14. The process as claimed in claim 8, further comprising modifying said precipitated silica with from
0.5 to 50 parts, based on 100 parts of precipitated silica, of at least one organosilane of the formula I,
II or III
206/425
[Rn-(RO)3-nSi-(Alk)m-(Ar)p]q[B] (I)Rn-(RO)3-nSi-(Alkyl) (II)
or
Rn(RO)3-nSi-(Alkenyl) (III)
wherein
Bis -SCN, -SH, -Cl, -NH2 (if q = 1) or -Sx- (if
q = 2);
R and Rare an alkyl group having 1 to 4 carbon atoms
or the phenyl radical, it being possible for all
radicals R and R to have in each case the
same meaning or a different meaning;
Ris a C1-C4 alkyl or C1-C4 alkoxy group;
nis 0, 1 or 2;
Alkis a divalent unbranched or branched
hydrocarbon radical having from 1 to 6
carbon atoms,
mis 0 or 1,
Aris an arylene radical having from 6 to 12
carbon atoms, preferably 6 carbon atoms,
pis 0 or 1 with the proviso that p and n are not
both 0,
xis a number from 2 to 8,
Alkylis a monovalent unbranched or branched
saturated hydrocarbon radical having from 1
to 20 carbon atoms, preferably from 2 to 8
carbon atoms;
Alkenylis a monovalent unbranched or branched
unsaturated hydrocarbon radical having from
2 to 20 carbon atoms, preferably from 2 to 8
carbon atoms; and
qis 1 or 2,
wherein said modifying is carried out during said forming of said aqueous waterglass solution, by
spray application of said organosilicone to said aqueous waterglass solution and subsequent
thermal conditioning of the mixture or by mixing said organosilane and said silica suspension with
subsequent drying and thermal conditioning.
207/425
15. The process as claimed in claim 7, wherein said precipitated silica is modified with from 0.5 to 50
parts, based on 100 parts of precipitated silica, of at least one organosilane.
16. The process as claimed in claim 7, wherein said precipitated silica is modified with from 1 to 15
parts, based on 100 parts of precipitated silica, of at least one organosilane.
17. A vulcanizable rubber mixture or vulcanizate comprising the precipitated silica as claimed in
claim 1.
18. A tire comprising a precipitated silica as claimed in claim 1.
19. A tire comprising a precipitated silica as claimed in claim 1, wherein said precipitated silica is
incorporated as a reinforcing filler in amounts of from 5 to 200 parts, based on 100 parts of rubber.
20. A vulcanizable rubber mixture or vulcanizate comprising the precipitated silica as claimed in
claim 1, wherein said said precipitated silica is incorporated as a reinforcing filler in amounts of from
5 to 200 parts, based on 100 parts of rubber.
208/425
21. JP2003201371 - 08.05.2003
RUBBER COMPOSITION, VULCANIZED RUBBER AND TIRE
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2003201371
Inventor(s):
ISHIZAKI SUSUMU [JP] (--)
Applicant(s):
BRIDGESTONE CORP [JP] (--); ISHIZAKI SUSUMU [JP] (--)
IP Class 4 Digits: C08L
IP Class:
C8L7/00; C8L9/00
E Class: B60C1/00H; B60C11/00; B60C11/14; C08K7/02+L21/00
Application Number:
WO2002JP11117 (20021025)
Priority Number: JP20010338299 (20011102); JP20020144856 (20020520)
Family: JP2003201371
Cited Document(s):
JP2229215; JP2000319451; JP5179070; JP10025373
Abstract:
A RUBBER COMPOSITION CONTAINING FINE PARTICLE CONTAINING ORGANIC SHORT FIBERS
IS CHARACTERIZED IN THAT THE MOH'S HARDNESS OF THE FINE PARTICLES IS HIGHER THAN
THE MOH'S HARDNESS MOH'S HARDNESS 1-2 OF ICE. A VULCANIZED RUBBER FORMED BY
VULCANIZING SUCH A COMPOSITION WITH SPECIFIC LONG FOAMS IS USED FOR A TIRE. SUCH
A TIRE AND ITS TREAD ALWAYS CARRY EFFICIENT MICRO DRAIN GROOVES WHICH EXHIBIT A
RELIABLE PERFORMANCE OF WATER MEMBRANE REMOVAL PERFORMANCE AND ARE
EXCELLENT IN ON-ICE PERFORMANCE FACE BRAKE / DRIVE PERFORMANCE FOR
SUFFICIENTLY EXHIBITING AN EDGE EFFECT OR A SPIKE EFFECT.
209/425
22. JP2003211460 - 07.08.2003
PROCESS FOR PRODUCTION OF RECLAIMED FLUORORUBBER VULCANIZATES AND
COMPOSITIONS FOR THE DEVULCANIZED FLUORORUBBERS TO BE RECLAIMED
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2003211460
Inventor(s):
OHTANI MITSUHIRO [JP] (--); TOKUHIRA KATSUSADA [JP] (--); OKUMURA
TSUNAYUKI [JP] (--)
Applicant(s): DAIKIN IND LTD [JP] (--); OHTANI MITSUHIRO [JP] (--); TOKUHIRA KATSUSADA
[JP] (--); OKUMURA TSUNAYUKI [JP] (--)
IP Class 4 Digits: C08L; B29C; B29K
IP Class:
C8L27/12; B29C35/02; B29K27/12
E Class: C08J11/12+L27/12
Application Number:
WO2003JP00643 (20030124)
Priority Number: JP20020019052 (20020128)
Family: JP2003211460
Cited Document(s):
JP6210633; JP61069805; JP54122350; US4148982
Abstract:
THE INVENTION PROVIDES A PROCESS FOR PRODUCING A RECLAIMED FLUORORUBBER
FROM A WASTE FLUORORUBBER VULCANIZATE THROUGH REVULCANIZATION; A
COMPOSITION FOR THE ABOVE REVULCANIZATION; AND RECLAIMED FLUORORUBBER
VULCANIZATES. A PROCESS FOR PRODUCTION OF RECLAIMED FLUORORUBBER
VULCANIZATES WHICH COMPRISES CONVERTING A WASTE FLUORORUBBER VULCANIZATE (A)
INTO A DEVULCANIZED FLUORORUBBER (B) BY THERMAL TREATMENT AND THEN
SUBJECTING THE DEVULCANIZED FLUORORUBBER (B) TO VULCANIZATION (2) TO FORM A
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RECLAIMED FLUORORUBBER VULCANIZATE (C), CHARACTERIZED IN THAT THE WASTE
FLUORORUBBER VULCANIZATE (A) IS ONE OBTAINED BY VULCANIZATION (1).
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23. JP2003221468 - 24.11.2004
RUBBER COMPOSITION, VULCANIZABLE RUBBER COMPOSITION, AND VULCANIZATE
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2003221468
Inventor(s):
TSUKADA AKIRA [JP] (--); NOMOTO HIROFUMI [JP] (--)
Applicant(s):
ZEON CORP [JP] (--)
IP Class 4 Digits: C08K; C08L
IP Class:
C8K3/22; C8K5/09; C8L9/02
E Class: C08K3/22+L9/02; C08K5/098+L9/02; C08K5/14+L9/02
Application Number:
EP20030703095 (20030130)
Priority Number: WO2003JP00931 (20030130); JP20020021912 (20020130)
Family: JP2003221468
Equivalent:
WO03064517
Abstract:
A RUBBER COMPOSITION COMPRISING (A) 100 WEIGHT PARTS OF A NITRILE GROUPCONTAINING COPOLYMER RUBBER HAVING AN IODINE VALUE OF NOT LARGER THAN 100 AND
COMPRISING 10-60% BY WEIGHT OF ALPHA , BETA -ETHYLENICALLY UNSATURATED NITRILE
MONOMER UNITS, AND (B) 3-200 WEIGHT PARTS OF AN ACID-ACCEPTOR SELECTED FROM
ZEOLITE COMPOUNDS, HYDROTALCITE COMPOUNDS AND ALUMINUM HYDROXIDE GEL, AND
OPTIONALLY (C) 3-100 WEIGHT PARTS OF A METAL SALT OF ALPHA , BETA -ETHYLENICALLY
UNSATURATED CARBOXYLIC ACID. A VULCANIZABLE RUBBER COMPOSITION COMPRISING
THIS RUBBER COMPOSITION AND (D) 0.2-10 WEIGHT PARTS OF AN ORGANIC ACID
VULCANIZING AGENT GIVES A RUBBER VULCANIZATE HAVING GOOD RESISTANCE TO
DETERIORATED OIL.Description:
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Technical Field
[0001] This invention relates to a rubber composition and a vulcaizable rubber composition, which
are useful as a material for a rubber vulcanizate having good resistance to deteriorated oil, and a
rubber vulcanizate having good resistance to deteriorated oil.
Background Art
[0002] In recent years, thermal circumstances and conditions in an engine room of an automobile
are becoming severe because of power-enhancement of an engine, adoption of a front engine/front
drive mechanism, and exhaust gas purification. Further, prolongation of life of lubricating oil for
automobile and reduction of fuel consumption are in progress. Therefore, lubricating oil capable of
being used for a long period of time under high-temperature conditions without exchange thereof is
eagerly desired. However, undesirable oxidation of lubricating oil proceeds due to contact with air,
leading to deterioration of the oil.
[0003] It has been reported that rubber is hardened by the contact with deteriorated lubricating oil,
and further that a hydrogenation product of an acrylonitrile-butadiene copolymer rubber has good
resistance to deteriorated oil (Toyoda Gousei Technical Review, vol. 26, No. 2, P51-56, 1984). A
rubber vulcanizate having improved resistance to deteriorated oil is now being eagerly desired.
Disclosure of the Invention
[0004] An object of the present invention is to provide a rubber composition which is useful as
material for a rubber vulcanizate having good resistance to deteriorated oil.
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[0005] The present inventors conducted researches to achieve the above-mentioned object, and
found that a rubber vulcanizate made by vulcanizing a rubber composition comprising a nitrile
group-containing copolymer rubber having a low iodine value and a specific acid-acceptor is
characterized in that, even when the rubber vulcanizate is placed in contact with deteriorated oil, it is
not subject to volume change nor to hardness change. On the basis of this finding, the present
invention has been completed.
[0006] Thus, in a first aspect of the present invention, there is provided a rubber composition
comprising (A) 100 parts by weight of a nitrile group-containing copolymer rubber having an iodine
value of not larger than 100 and comprising 10 to 60% by weight of alpha , beta -ethylenically
unsaturated nitrile monomer units, and (B) 3 to 200 parts by weight of at least one kind of an acidacceptor selected from zeolite compounds, hydrotalcite compounds and aluminum hydroxide gel.
[0007] In a second aspect of the present invention, there is provided a vulcanizable rubber
composition comprising (A) 100 parts by weight of the above-mentioned nitrile group-containing
copolymer rubber, (B) 3 to 200 parts by weight of at least one kind of an acid-acoeptor selected from
zeolite compounds, hydrotalcite compounds and aluminum hydroxide gel, and (D) 0.2 to 10 parts by
weight of an organic peroxide vulcanizing agent.
[0008] In a third aspect of the present invention, there is provided a rubber vulcanizate made by
vulcanizing the above-mentioned vulcanizable rubber composition.
Best Mode for Carrying Out the Invention
[0009] The rubber composition of the present invention comprises (A) 100 parts by weight of a
nitrile group-containing copolymer rubber having an iodine value of not larger than 100 and
comprising 10 to 60% by weight of alpha , beta -ethylenically unsaturated nitrile monomer units, and
(B) 3 to 200 parts by weight of at least one kind of an acid-acceptor selected from zeolite
compounds, hydrotalcite compounds and aluminum hydroxide gel.
[0010] The nitrile group-containing copolymer rubber used in the present invention is a rubber
made by copolymerizing an alpha , beta -ethylenically unsaturated nitrile monomer with other
monomer, and the rubber comprises alpha , beta -ethylenically unsaturated nitrile monomer units in
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an amount of 10 to 60% by weight, preferably 25 to 55% by weight and more preferably 30 to 50%
by weight, based on the weight of the nitrile group-containing copolymer rubber. If the amount of
alpha , beta -ethylenically unsaturated nitrile monomer units is too small, a rubber vulcanizate has
poor resistance to deteriorated oil. In contrast, if the amount of alpha , beta -ethylenically unsaturated
nitrile monomer units is too large, a rubber vulcanizate has poor cold resistance. As specific
examples of the alpha , beta -ethylenically unsaturated nitrile monomer, there can be mentioned
acrylonitrile, methacrylonitrile and alpha -chloroacrylonitrile. Of these, aorylonitrile is preferable.
[0011] The monomer to be copolymerized with the alpha , beta -ethylenically unsaturated nitrile
monomer for the preparation of the nitrile group-containing copolymer rubber includes, for example,
conjugated diene monomers, non-conjugated diene monomers and alpha -olefin monomers. As
specific examples of the conjugated diene monomer, there can be mentioned 1,3-butadiene,
isoprene, 2,3-dimethyl-1,3-butadiene and 1,3-pentadiene. Of these, 1,3-butadiene is preferable. The
non-conjugated diene monomer preferably includes those which have 5 to 12 carbon atoms, and, as
specific examples thereof, there can be mentioned 1,4-pentadiene, 1,4-hexadiene, vinylnorbornene
and dicyclopentadiene. The alpha -olefin monomer preferably includes those which have 2 to 12
carbon atoms, and, as specific examples thereof, there can be mentioned ethylene, propylene, 1butene, 4-methyl-1-pentene, 1-hexene and 1-octene.
[0012] The content of units of the monomer copolymerized with the alpha , beta -ethylenically
unsaturated nitrile monomer in the nitrile group-containing copolymer rubber (A) is in the range of 40
to 90% by weight, preferably 45 to 75% by weight and more preferably 50 to 70% by weight, based
on the weight of the copolymer rubber (A).
[0013] In addition to the above-mentioned monomer, an aromatic vinyl monomer, a fluorinecontaining vinyl monomer, an alpha , beta -ethylenically unsaturated monocarboxylic acid, an alpha ,
beta -ethylenically unsaturated polycarboxylic aoid or its anhydride, or a copolymerizable antioxidant
may be copolymerized with the alpha , beta -ethylenically unsaturated nitrile monomer.
[0014] As specific examples of the optionally copolymerized monomer, there can be mentioned
aromatic vinyl monomers such as styrene, alpha -methylstyrene and vinylpyridine; fluorinecontaining vinyl monomers such as fluoroethyl vinyl ether, fluoropropyl vinyl ether, otrifluoromethylstyrene, vinyl pentafluorobenzoate, difluoroethylene and tetrafluorethylene; alpha ,
beta -ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid;
alpha , beta -ethylenically unsaturated polycarboxylic acids such as itaconic acid, fumaric acid and
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maleic acid; alpha , beta -ethylenically unsaturated polycarboxylic acid anhydrides such as itaconic
anhydride and maleic anhydride; and copolymerizable anitioxidants such as N-(4-anilinophenyl)acrylamide, N-(4-anilinophenyl)methacrylamide, N-(4-anilinophenyl)cinnmamide, N-(4anilinophenyl)orotonamide, N-phenyl-4-(3-vinylbenzyloxy)aniline and N-phenyl-4-(4vinylbenzyloxy)aniline.
[0015] The nitrile group-containing copolymer rubber (A) has an iodine value of not larger than 100,
preferably not larger than 50, and more preferably not larger than 25. If the iodine value of the rubber
(A) is larger than 100, a rubber vulcanizate has poor resistance to deteriorated oil. The nitrile groupcontaining copolymer rubber (A) can be produced by conducting a copolymerization in a
conventional manner, but, if the copolymer thus-prepared by copolymerization has too large iodine
value, the copolymer can be hydrogenated by a conventional hydrogenation procedure whereby
unsaturated bonds in the main chain of copolymer are saturated to lower the iodine value to the
desired degree.
[0016] The nitrile group-containing copolymer rubber (A) preferably has a Mooney viscosity
(ML1+4, 100 DEG C) in the range of 10 to 300, more preferably 20 to 250 and especially preferably
30 to 200. If the Mooney viscosity is too small, a rubber vulcanizate is liable to have poor mechanical
properties. In contrast, the Mooney viscosity is too large, a rubber composition is liable to have poor
processability.
[0017] The acid-acceptor (B) used in the present invention is selected from zeolite compounds,
hydrotalcite compounds and aluminum hydroxide gel.
[0018] The zeolite compound preferably includes those which are represented by the following
general formula (1):
"(1)" M2/nO.Al2O3.mSiO2.sH2O
wherein M is a cation such as, for example, Na, K, Ca, Mg, Ba and Fe. Preferable cations are Na, K,
Ca and Ba. "n" is a valency of M, "m" is a number in the range of 2 to 10, and "s" is a number in the
range of 2 to 7.
[0019] The zeolite compounds used are not particularly limited, provided that they are expressed
by the above formula (1). The zeolite compound may be either natural zeolite comprising aluminum
silicate as principal ingredient, obtained from tuffaceous zeolite, or synthetic zeolite produced by a
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chemical process from a pure raw material. As specific examples of the zeolite compound, there can
be mentioned:
Na2O.Al2O3.2SiO2.sH2O (2 </= s </= 7),
Na2O.Al2O3.3SiO2.sH2O (2 </= s </= 7),
and
CaO.Al2O3.3SiO2.sH2O (2 </= s </= 7).
[0020] The hydrotalcite compound used preferably includes those which are represented by the
following general formula (2):
"(2)" MgxZnyAlz(OH)2(x+y)+3z-2CO3.wH2O
wherein 0 < x < 10, 0 </= y < 10, 1 </= x+y <10, 1 </= z < 5, 0 </= w. The hydrotalcite compound
may be either natural talcite, or synthetic zeolite produced by a chemical process from a pure raw
material. As specific examples of the hydrotalcite compound, there can be mentioned:
Mg4.3Al2(OH)12.6CO3.wH2O (0 < W),
Mg4.5Al2(OH)13CO3.3.5H2O,
Mg4.5Al2(OH)13CO3,
Mg4Al2(OH)12CO3.3.5H2O,
Mg6Al2(OH)16CO3.4H2O.
Mg5Al2(OH)14CO3.4H2O.
Mg3Al2(OH)10CO3.1.7H2O,
and
Mg3ZnAl2(OH)12CO3.
[0021] The aluminum hydroxide gel used preferably includes those which are represented by the
following general formula (3):
"(3)" a[M].Al2O3.b(CO2).cH2O
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wherein [M] is at least one member selected from an oxide of a metal of group 1 of the periodic
table, an oxide of a metal of group 2 of the periodic table and an organic acid salt of a metal of group
1 or group 2 of the periodic table, "a" is 0 or a positive number, "b" is a positive number and "c" is a
positive number. "a" preferably satisfies 0 </= a < 2, more preferably 0 </= a < 1. 5, and especially
preferably 0 </= a < 1. "b" preferably satisfies 0.1 < b </= 1, more preferably 0.15 < b </= 1, and
especially preferably 0.2 < b </= 1. "c" preferably satisfies 2 </= c < 10, more preferably 2 </= c < 8,
and especially preferably 2 </= c </= 6.
[0022] The acid acceptor may be used either alone or as a combination of at least two thereof.
[0023] The content of acid-acceptor (B) is in the range of 3 to 200 parts by weight, preferably 5 to
100 parts by weight, based on 100 parts by weight of the nitrile group-containing copolymer rubber
(A). If the content of acid-acceptor (B) is too small, a rubber vulcanizate has poor resistance to
deteriorated oil. In contrast, if the content of acid-acceptor (B) is too large, a rubber vulcanizate is
liable to have poor mechanical properties.
[0024] Preferably, the rubber composition of the present invention further comprises a metal salt of
alpha , beta -ethylenically unsaturated carboxylic acid (C).
[0025] The alpha , beta -ethylenically unsaturated carboxylic acid constituting the metal salt
thereof has at least one free carboxyl group, and includes, for example, an alpha , beta ethylenically unsaturated monocarboxylic acid, an alpha , beta -ethylenically unsaturated
dicarboxylic acid, and a monoester of an alpha , beta -ethylenically unsaturated dicarboxylic acid.
As specific examples of the alpha , beta -ethylenically unsaturated carboxylic acid, there can be
mentioned alpha , beta -ethylenically unsaturated monocarboxylic acids such as acrylic acid,
methacrylic acid, crotonic acid and 3-butenoic acid; alpha , beta -ethylenically unsaturated
dioarboxylic acids such as maleic acid, fumaric acid and itaconic acid; and monoesters of alpha ,
beta -ethylenically unsaturated dicarboxylic acid such as monomethyl maleate, monoethyl maleate,
monomethyl itaconate and monoethyl itaconate. Of these, an alpha , beta -ethylenically unsaturated
carboxylic acid having no ester group is preferable because a rubber vulcanizate made from the
rubber composition has good mechanical properties. alpha , beta -Ethylenically unsaturated
monocarboxylic acid is more preferable. Methacrylio acid is especially preferable.
[0026] The metal constituting the metal salt of alpha , beta -ethylenically unsaturated carboxylic
acid (C) preferably includes zinc, magnesium, calcium, barium, titanium, chromium, iron, cobalt,
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nickel, aluminum, tin and lead. Of these, zinc, magnesium, calcium and aluminum are more
preferable. Zinc is especially preferable.
[0027] The content of the metal salt of alpha , beta -ethylenically unsaturated carboxylic acid (C) is
in the range of 3 to 100 parts by weight, preferably 10 to 80 parts by weight and more preferably 25
to 70 parts by weight, based on 100 parts by weight of the nitrile group-containing copolymer rubber
(A). A rubber vulcanizate made from a rubber composition comprising too small amount of the metal
salt of alpha , beta -ethylenically unsaturated carboxylic acid (C) has poor mechanical strength. In
contrast, a rubber composition comprising too large amount of the metal salt of alpha , beta ethylenically unsaturated carboxylic acid (C) is difficult to knead.
[0028] The metal salt of alpha , beta -ethylenically unsaturated carboxylic acid (C) in the rubber
composition may be formed by a procedure wherein an alpha , beta -ethylenically unsaturated
carboxylic acid and a metal or a metal compound are incorporated at a step of preparing the rubber
composition whereby the alpha , beta -ethylenically unsaturated carboxylic acid and the metal or
metal compound are allowed to react with each other within the rubber composition. The metal salt
(C) formed by this procedure is preferable because the metal salt (C) is finely divided and readily
dispersed in the rubber composition. As specific examples of the metal compound used for the
formation of the metal salt (C), there can be mentioned oxides, hydroxides and carbonic acid salts of
the above-mentioned metals. Zinc oxide and zinc carbonate are especially preferable.
[0029] In the case when an alpha , beta -ethylenically unsaturated carboxylic acid and a metal or
a metal compound are allowed to react with each other within the rubber composition, it is preferable
that 1 mole of an alpha , beta -ethylenically unsaturated carboxylic acid is allowed to react with 0.5
to 3.2 moles, preferably 0.7 to 2.5 moles, as amount of metal, of a metal or a metal compound. When
the relative amount of a metal or metal compound is too small or too large, the reactivity between an
alpha , beta -ethylenically unsaturated carboxylic acid and a metal or a metal compound is low.
However, in the case when zinc oxide, zinc carbonate or zinc hydroxide is incorporated as the metal
compound for the formation of the metal salt (C), even when the amount of the metal compound is
larger than the above-range, a problem would not arise because the excessive amount of metal
functions as a vulcanization accelerator.
[0030] The metal salt (C) is preferably in a finely divided form, provided that handling properties
are acceptable. More specifically the content of particles having a particle diameter of at least 20
mu m in the metal salt (C) is preferably not larger than 5% by weight. For this reason, in the case
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when the metal salt (C) is incorporated in a rubber composition, the metal salt (C) is preferably finely
divided previously by classifying the particles, for example, using an air-classification apparatus or a
sieve classification apparatus. In the case when a metal compound is incorporated in a rubber
composition to form the metal salt (C) therein, the metal compound is preferably finely divided
previously by classifying the particles similarly.
[0031] The rubber composition of the present invention may comprise auxiliary ingredients which
are generally used for rubbers. Such ingredients include, for example, reinforcing agents such as
carbon black, silica and staple fibers; fillers such as calcium carbonate, clay, talc and calcium
silicate; plasticizers; pigments; antioxidants; tackifiers; processing aids; and scorch retarders.
Rubbers other than the nitrile group-containing copolymer rubber (A), and resins may be
incorporated in the rubber composition, provided that the effect of the present invention can be
substantially obtained.
[0032] The method of preparing the rubber composition of the present invention is not particularly
limited. The ingredients may be mixed and kneaded together by conventional procedures generally
adopted for the preparation of rubber compositions.
[0033] A vulcanizable rubber composition of the present invention comprises (A) 100 parts by
weight of the above-mentioned nitrile group-containing copolymer rubber, (B) 3 to 200 parts by
weight of at least one kind of an acid-acceptor selected from zeolite compounds, hydrotalcite
compounds and aluminum hydroxide gel, and (D) 0.2 to 10 parts by weight of an organic peroxide
vulcanizing agent.
[0034] The organic peroxide vulcanizing agent (D) used in the present invention preferably
includes those which are used as vulcanizing agents in the rubber industry, such as, for example,
dialkyl peroxides, diacyl peroxides and peroxy-esters. Dialkyl peroxides are especially preferable. As
specific examples of the organic peroxide vulcanizing agent (D), there can be mentioned dialkyl
peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl-peroxy)-3hexyne, 2,5-dimethyl-2,5-dl(tert-butyl-peroxy)-3-hexane and 1,3-bis(tert-butyl-peroxyisopropyl)benzene; diacyl peroxides such as benzoyl peroxide and isobutyryl peroxide; and peroxyesters such as 2,5-dimethyl- 2,5-bis(benzoylperoxy)hexane and tert-butyl-peroxy-isopropyl
carbonate. The organic peroxide vulcanizing agent (D) may be used either alone or as a combination
of two or more thereof.
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[0035] The amount of organic peroxide vulcanizing agent (D) is in the range of 0.2 to 10 parts by
weight, preferably 0.3 to 7 parts by weight and especially preferably 0. 5 to 5 parts by weight, based
on 100 parts by weight of the nitrile group-containing copolymer rubber (A). If the amount of organic
peroxide vulcanizing agent (D) is too small, a rubber vulcanizate has low vulcanization density and
large permanent set. In contrast, if the amount of organic peroxide vulcanizing agent (D) is too large,
a rubber vulcanizate tends to have poor rubber elasticity.
[0036] A vulcanization aid may be used in combination with the organic peroxide vulcanizing agent
(D), and, as specific examples of the vulcanization aid, there can be mentioned, for example, zinc
oxide, magnesium oxide, triallyl oyanurate, trimethylolpropane trimethacrylate and N,N'-m-phenylene
bismaleimide. The vulcanization aid can be incorporated as a dispersion thereof in clay, calcium
carbonate or silica in the vulcanizable rubber composition to enhance the processability of the
composition. The kind and amount of vulcanization aid are not particularly limited, and can be
appropriately chosen depending upon the use of rubber vulcanizate, the properties required for
rubber vulcanizate, and the kind and amount of the organic peroxide vulcanizing agent (D).
[0037] The method for preparing the vulcanizable rubber composition of the present invention is
not particularly limited. The vulcanizable rubber composition can be prepared by the conventional
method widely adopted for the preparation of general vulcanizable rubber compositions. The rubber
ingredients may be kneaded together, for example, by roll mixing or Banbury mixing. However, when
and after an organic peroxide vulcanizing agent (D) and a vulcanization aid are incorporated, the
rubber composition must be kneaded at a temperature lower than the vulcanization-initiation
temperature so as to avoid the undesirable curing during kneading.
[0038] A rubber vulcanizate of the present invention is made by vulcanizing the above-mentioned
vulcanizable rubber composition. The vulcanization can be effected by heating the vulcanizable
rubber composition. Generally, the heating for vulcanization is carried out either after the
vulcanizable rubber composition is shaped, or simultaneously with the shaping of the composition.
[0039] The heating temperature is preferably in the range of 100 to 200 DEG C, more preferably
135 to 195 DEG C and especially preferably 140 to 190 DEG C. When the heating temperature is too
low, a long heating time is required for vulcanization or a rubber vulcanizate is liable to have reduced
vulcanization density. In contrast, when the heating temperature is too high, a defective shaped
article tends to be produced.
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[0040] The vulcanization time varies depending upon the vulcanization procedure, the
vulcanization temperature and the shape of rubber vulcanizate, but is preferably chosen from the
range of 1 minute to 4 hours in view of the vulcanization density and production efficiency. The
heating procedure may appropriately be chosen from those which are widely adopted for the
vulcanization of rubbers, such as press heating, steam heating, oven heating and hot-air heating.
[0041] The vulcanization conditions vary depending upon the shape and size of rubber vuloanizate.
In some cases, the surface portion of shaped article is completely vulcanized but the central part
thereof is not completely vulcanized. In these cases, after the vulcanization is carried out under the
above-mentioned conditions, a secondary vulcanization may be additionally carried out wherein the
rubber vulcanizate is maintained at a higher temperature.
[0042] The invention will now be specifically described by the following examples and comparative
examples. In these examples, parts and % relating to a composition of ingredients are by weight.
[0043] Characteristics of a rubber vulcanizate were evaluated by the following methods.
(1) Elongation
[0044] A vulcanizable rubber composition was press-vulcanized at a temperature of 170 DEG C
under a pressure of 10 MPa for 20 minutes to obtain a sheet having a thickness of 2 mm. The sheet
was punched to prepare a test specimen according to JIS K6251. Using the specimen, elongation
(%) was measured according to JIS K6251.
(2) Resistance to deteriorated oil
[0045] According to JIS K6258, a test specimen was immersed in a lubricating oil for 168 hours,
and the resistance to deteriorated oil was evaluated by the change (%) in volume as calculated from
the weights of specimen as measured before and after the immersion-in-oil. In this test, air was blown
gently at a rate of 50 ml/min into 1,200 ml of the lubricating oil maintained at 150 DEG C. Similarly,
the change (%) in elongation was calculated from the weights of specimen as measured before and
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after the immersion-in-oil. The measurement of elongation was carried out in the same manner as
mentioned above in (1).
[0046] As the lubricating oil, the following three kinds of oil were used.
Oil "a": IRM 902.
Oil "b": API.SJ/GF-second grade oil (Ultra-SUPER MILD SJ, available from Honda Motor Co., Ltd.,
engine oil for four-wheeled vehicle four-stroke engine).
Oil "c": mixed oil comprised of 99.6% by volume of said API.SJ/GF-second grade oil and 0.4% by
volume of nitric acid.
[0047] As the absolute values of the change in volume and the change in elongation are smaller,
the resistance to deteriorated oil is more excellent.
Reference Exemple 1 (Preparation of aluminum hydroxide gel)
[0048] An aqueous 0.9M aluminum sulfate solution and an aqueous 0.6M sodium carbonate
solution were mixed at a ratio of 4:3 by volume. To the mixed solution, 2M of sodium hydroxide was
added to adjust the pH value to 7.5, and the mixed solution was maintained at 30 DEG C. A one liter
reaction vessel was charged with 0.5 liter of water, and, while the water was vigorously stirred at 30
DEG C, the above-mentioned mixed solution was added thereto at a flow rate of 0.2 liter/min. A
reaction was conducted for one hour while the reaction liquid was allowed to overflow. The thuscollected overflowing aqueous suspension was dehydrated under a reduced pressure to give a solid.
The solid was thoroughly washed with an aqueous 0.05M calcium chloride solution, and ionexchange was effected. The ion-exchanged solid was further thoroughly washed with water, and
then, dried at about 70 DEG C for 20 hours.
[0049] Chemical analysis of the thus-obtained aluminum hydroxide gel revealed that it had a
chemical composition expressed by the formula: a(CaO).Al2O3.b(CO2).cH2O (0.05 < a < 0.15, 0.5 <
b < 0.6, 4.5
Example 1
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[0050] The following ingredients were kneaded together at 50 DEG C by a roll mill to prepare a
vulcanizable rubber composition.
(1) 100 parts of nitrile group-containing copolymer rubber A ("Zetpol 2010H", available from Zeon
Corporation, hydrogenation product of an acrylonitrile-butadiene copolymer rubber, iodine value: 11,
acrylonitrile unit content: 36% by weight, Mooney viscosity (ML1+4, 100 DEG C): 135),
(2) 20 parts of zeolite compound ("Mizukalizer-DS", available from Mizusawa Ind. Chemicals, Co.,
Na2O.Al2O3.2SiO2.sH2O, 2 </= s </= 7),
(3) 15 parts of zinc methacrylate,
(4) 10 parts of zinc oxide #1,
(5) 8 parts of tris(2-ethylhexyl) trimellitate (plasticizer),
(6) 1.5 parts of substituted diphenylamine ("Nauguard 445", available from Uniroyal Co.,
antioxidant),
(7) 1.5 parts of 2-mercaptobenzothiazole zinc salt ("Nocrac MBZ", available from Ouchishinko
Chem. Ind. Co., antioxidant),
(8) 6 parts of 1,3-bis(t-butyl-peroxyisopropyl)benzene, content 40% (organic peroxide content: 2.4
parts, "Vulcup 40KE", available from Hercules Co.).
[0051] The vulcanizable rubber composition was press-vulcanized at 170 DEG C under a pressure
of 10 MPa for 20 minutes to prepare a sheet having a thickness of 2 mm. The sheet was punched by
No. 3 dummbbell die to prepare a test specimen. Using the specimen, elongation and resistance to
deteriorated oil were evaluated. The results are shown in Table 1.
Example 2
[0052] A rubber vulcanizate was made and its characteristics were evaluated by the same
procedures as described in Example 1 wherein a hydrotalcite compound ("DHT-4A" available from
Kyouwa Chem. Ind. Co., Mg4.3Al2(OH)12.6CO3.wH2O, w: positive number) was used instead of the
zeolite compound with all other conditions remaining the same. The evaluation results are shown in
Table 2.
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Example 3
[0053] A rubber vulcanizate was made and its characteristics were evaluated by the same
procedures as described in Example 1 wherein the aluminum hydroxide gel prepared in Reference
Example 1 was used instead of the zeolite compound with all other conditions remaining the same.
The evaluation results are shown in Table 2.
Example 4
[0054] A rubber vulcanizate was made and its characteristics were evaluated by the same
procedures as described in Example 1 wherein nitrile group-containing copolymer rubber B ("Zetpol
1000L", available from Zeon Corporation, hydrogenation product of an acrylonitrile-butadiene
copolymer rubber, iodine value: below 7, acrylonitrile unit content: 44% by weight, Mooney viscosity
(ML1+4, 100 DEG C): 70) was used instead of the nitrile group- containing copolymer rubber B. All
other conditions remained the same. The evaluation results are shown in Table 2.
Comparative Example 1
[0055] A rubber vulcanizate was made and its characteristics were evaluated by the same
procedures as described in Example 1 wherein SRF carbon black ("Asahi #50", available from Asahi
Carbon Co.) was used instead of the zeolite compound with all other conditions remaining the same.
The evaluation results are shown in Table 2.
Comparative Example 2
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[0056] A rubber vulcanizate was made and its characteristics were evaluated by the same
procedures as described in Example 1 wherein calcium hydroxide was used instead of the zeolite
compound with all other conditions remaining the same. The evaluation results are shown in Table 2.
Comparative Example 1
[0057] A rubber vulcanizate was made and its characteristics were evaluated by the same
procedures as described in Example 1 wherein magnesium oxide was used instead of the zeolite
compound with all other conditions remaining the same. The evaluation results are shown in Table 2.
[0058] As seen from Table 1, the results for evaluation of resistance to deteriorated oil varied to
some extent depending upon the particular lubricating oil used. However, rubber compositions
which did not contain any of a zeolite compound, a hydrotalcite compound and aluminum hydroxide
gel gave rubber vulcanizates having poor resistance to deteriorated oil, that is, exhibiting undesirably
large change in absolute value of volume and in absolute value of elongation (Comparative
Examples 1 to 3).
[0059] In contrast, the rubber compositions of the present invention gave rubber vulcanizates
exhibiting good resistance to deteriorated oil (Examples 1 to 4).
Industrial Applicability
[0060] In the case when a rubber composition of the present invention comprising a nitrile groupcontaining copolymer rubber and a specific acid-acceptor is vulcanized with an organic acid
vulcanizing agent, the resulting rubber vulcanizate is characterized in that, when the vulcanizate is
brought into contact with deteriorated oil, the vulcanizate exhibits reduced change in volume and
hardness and cracks do not occur to any appreciable extent, while good properties of the nitrile
group-containing copolymer rubber are maintained.
226/425
[0061] In view of the beneficial characteristics, the rubber vulcanizate can be used as rubber parts,
which are placed in contact with lubricating oil for vehicles, such as, for example, hoses, packings
and seals, which are equipped in a driving device of a vehicle.Claims:
1. A rubber composition comprising:
(A) 100 parts by weight of a nitrile group-containing copolymer rubber having an iodine value of not
larger than 100 and comprising 10 to 60% byweight of alpha , beta -ethylenically unsaturated nitrile
monomer units, and
(B) 3 to 200 parts by weight of at least one kind of an acid-acceptor selected from zeolite
compounds, hydrotalcite compounds and aluminum hydroxide gel.
2. The rubber composition according to claim 1, wherein the nitrile group-containing copolymer
rubber (A) comprises 10 to 60% by weight of alpha , beta -ethylenically unsaturated nitrile monomer
units, and 40 to 90% by weight of units derived from at least one kind of monomer selected from
conjugated diene monomers, non-conjugated diene monomers and alpha -olefin monomers.
3. The rubber composition according to claim 1, wherein the nitrile group-containing copolymer
rubber (A) comprises 25 to 55% by weight of alpha , beta -ethylenically unsaturated nitrile monomer
units, and 45 to 75% by weight of units derived from at least one kind of monomer selected from
conjugated diene monomers, non-conjugated diene monomers and alpha -olefin monomers.
4. The rubber composition according to any one of claims 1 to 3, wherein the nitrile group-containing
copolymer rubber (A) has an iodine value of not larger than 50.
5. The rubber composition according to any one of claims 1 to 4, wherein the nitrile group-containing
copolymer rubber (A) has a Mooney viscosity (ML1+4, 100 DEG C) in the range of 10 to 300.
6. The rubber composition according to any one of claims 1 to 5, wherein the acid-acceptor (B) is at
least one compound selected from:
zeolite compounds represented by the following general formula (1):
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"(1)" M2/nO.Al2O3.mSiO2.sH2O
wherein M is a cation, "n" is a valency of M, "m" is a number in the range of 2 to 10, and "s" is a
number in the range of 2 to 7;
hydrotalcite compounds represented by the following general formula (2):
"(2)" MgxZnyAlz(OH)2(x+y)+3z-2CO3.wH2O
wherein 0 < x < 10, 0 </= y < 10, 1 </= x+y < 10, 1 </= z < 5, 0 </= w; and
aluminum hydroxide gel represented by the following general formula (3):
"(3)" a[M].Al2O3.b(CO2).cH2O
wherein [M] is at least one member selected from an oxide of a metal of group 1 of the periodic
table, an oxide of a metal of group 2 of the periodic table, and an organic acid salt of a metal of
group 1 or group 2 of the periodic table, "a" is 0 or a positive number, "b" is a positive number and "c"
is a positive number.
7. The rubber composition according to any one of claims 1 to 6, wherein the content of acidacceptor (B) is in the range of 5 to 100 parts by weight based on 100 parts by weight of the nitrile
group-containing copolymer rubber (A).
8. The rubber composition according to any one of claims 1 to 7, which further comprise (C) a metal
salt of alpha , beta -ethylenically unsaturated carboxylic acid in an amount of 3 to 100 parts by
weight based on 100 parts by weight of the nitrile group-containing copolymer rubber (A).
9. The rubber composition according to claim 8, wherein the content of the metal salt of alpha , beta
-ethylenically unsaturated carboxylic acid (C) is in the range of 10 to 80 parts by weight based on
100 parts by weight of the nitrile group-containing copolymer rubber (A).
10. The rubber composition according to claim 8 or 9, wherein the metal salt of alpha , beta ethylenically unsaturated carboxylic acid (C) in the rubber composition is formed by a procedure
wherein an alpha , beta -ethylenically unsaturated carboxylic acid and a metal or a metal compound
are incorporated at a step of preparing the rubber composition whereby the alpha , beta ethylenically unsaturated carboxylic acid and the metal or metal compound are allowed to react with
each other within the rubber composition.
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11. The rubber composition according to claim 10, wherein 1 mole of an alpha , beta -ethylenically
unsaturated carboxylic acid is allowed to react with 0.5 to 3.2 moles, as amount of metal, of the metal
or the metal compound.
12. The rubber composition according to any one of claims 8 to 11, wherein the (C) is a salt of an
alpha , beta -ethylenically unsaturated carboxylic acid having no ester group with a metal selected
from zinc, magnesium, calcium and aluminum.
13. A vulcanizable rubber composition comprising the rubber composition as claimed in any one of
claims 1 to 12, and (D) an organic peroxide vulcanizing agent in an amount in the range of 0.2 to 10
parts by weight based on 100 parts by weight of the nitrile group-containing copolymer rubber (A).
14. The vulcanizable rubber composition according to claim 13, wherein the amount of organic
peroxide vulcanizing agent (D) is in the range of 0.3 to 7 parts by weight based on 100 parts by
weight of the nitrile group-containing copolymer rubber (A).
15. The vulcanizable rubber composition according to claim 13 or 14, wherein the organic peroxide
vulcanizing agent (D) is at least one kind of a peroxide selected from dialkyl peroxides, dacyl
peroxides and peroxy-esters.
16. A rubber vulcanizate made by vulcanizing the vulcanizable rubber composition as claimed in any
of claims 13 to 15.
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24. JP2003221469 - 07.08.2003
RUBBER COMPOSITION, VULCANIZABLE RUBBER COMPOSITION, AND VULCANIZATE
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2003221469
Inventor(s):
TSUKADA AKIRA [JP] (--); NOMOTO HIROFUMI [JP] (--)
Applicant(s):
ZEON CORP [JP] (--); TSUKADA AKIRA [JP] (--); NOMOTO HIROFUMI [JP] (--)
IP Class 4 Digits: C08K; C08L
IP Class:
C8K5/09; C8L9/02
E Class: C08K5/098+L9/02; C08K5/14+L9/02
Application Number:
WO2003JP00933 (20030130)
Priority Number: JP20020021914 (20020130)
Family: JP2003221469
Cited Document(s):
JP3188138; JP1311142; JP1306445
Abstract:
A RUBBER COMPOSITION WHICH COMPRISES 100 PARTS BY WEIGHT OF A NITRILE
COPOLYMER RUBBER (A) HAVING AN IODINE VALUE OF 20 OR LOWER AND A CONTENT OF
ALPHA,SS-ETHYLENICALLY UNSATURATED NITRILE MONOMER UNITS OF 40 TO 60 WT.% AND 3
TO 100 PARTS BY WEIGHT OF A METAL SALT OF AN ALPHA,SS-ETHYLENICALLY UNSATURATED
CARBOXYLIC ACID (B). ALSO PROVIDED IS A VULCANIZABLE RUBBER COMPOSITION
COMPRISING THIS RUBBER COMPOSITION AND INCORPORATED THEREIN 0.2 TO 10 PARTS BY
WEIGHT OF AN ORGANIC-PEROXIDE VULCANIZING AGENT (C). THE VULCANIZABLE
COMPOSITION GIVES A RUBBER VULCANIZATE HAVING EXCELLENT RESISTANCE TO
DETERIORATING OILS.
230/425
25. JP2004250709 - 26.08.2004
HYDROGENATED NITRILE BUTADIENE RUBBER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=JP2004250709
Inventor(s):
ACHTEN DIRK [DE] (--)
IP Class 4 Digits: B32B
IP Class:
B32B11/00
E Class: C08K5/14+L15/00B; C08L15/00B+B4B
Application Number:
US20040778429 (20040213)
Priority Number: DE20031007137 (20030220)
Family: JP2004250709
Equivalent:
CA2458125; DE10307137; EP1449874
Abstract:
THE PRESENT INVENTION RELATES TO A COMPOSITION CONTAINING A HYDROGENATED
NITRILE-BUTADIENE RUBBER (HNBR), A PEROXIDE CROSSLINKING SYSTEM AND A
RESORCINOL-FORMALDEHYDE RESIN, TO A PROCESS FOR THE PREPARATION OF THE
COMPOSITION, TO THE USE OF THE COMPOSITION AS AN ADHESION PROMOTER, AND ALSO
TO A MULTILAYER PRODUCT CONTAINING THE COMPOSITION ACCORDING TO THE PRESENT
INVENTION.Description:
FIELD OF THE INVENTION
[0001] The present invention relates to a composition containing a hydrogenated nitrile-butadiene
rubber (HNBR), a peroxide crosslinking system and a resorcinol-formaldehyde resin, to a process for
the preparation of the HNBR composition, to the use of the HNBR composition as an adhesion
promoter, and also to a multilayer product containing the composition according to the present
invention.
231/425
BACKGROUND OF THE INVENTION
[0002] There is a great need for compositions which can be used as adhesive bases for untreated
fabrics and reinforcing materials. Untreated fabrics and reinforcing materials are understood in this
context as being fabrics and reinforcing materials that have not undergone special surface treatment
for adhesion purposes, e.g. by means of coating processes from solution (impregnation processes)
or using latex dips. The bond between the surface of the carrier material and the rubber must be
sufficiently strong that it does not constitute the weak point in the composite system.
[0003] The direct reaction of the rubber with unpretreated carrier material and subsequent
peroxide crosslinking is not known in the prior art. Analogous direct adhesion processes are only
systems vulcanizable with sulfur, such as polychloroprene and nitrile rubber, described in Handbuch
fьr die Gummiindustrie, 2nd Edition, 1991, p. 500, published by Bayer AG. The use of this process in
peroxide vulcanized systems based on HNBR is not disclosed in the prior art.
[0004] In order to ensure good bonding of the actual rubber that is to be peroxide crosslinked to
the carrier material, the latter must be pretreated. For the pretreatment, the carrier materials are
treated, for example, with a latex or a solution, for the application of a so-called finishing layer. Such
finishing layers contain several chemically different constituents. These generally consist of a rubber
selected from the group consisting of polychloroprene, polyvinylpyridine, polybutadiene or
polybutadiene copolymers, the copolymers being selected from the group consisting of acrylonitrile,
styrene, or mixtures of those polymers. Furthermore, it is often appropriate to mix with the latex
additional resins, such as resorcinol resins with hardeners such as formaldehyde (or formaldehyde
donors) and optionally silane compounds. Such latices are referred to as RFL latex (resorcinolformaldehyde latex).
[0005] The carrier material is immersed in the latex, dried and reacted fully, and then the actual
rubber is vulcanized onto the carrier material so pretreated. Vulcanization can be carried out both
with sulfur or sulfur systems and peroxide.
[0006] The fabrics impregnated with conventional latices based on polybutadiene or
polybutadiene copolymers, polychloroprene or polyvinylpyridine exhibit distinct weaknesses,
particularly after ageing, when peroxide crosslinked rubbers are used, which are employed in the
next step of manufacture.
[0007] In order to improve the ageing properties, EP-B1 0 252 264 and U.S. Pat. No. 5,176,781
therefore disclose the use of latices based on partially hydrogenated HNBR and/or in combination
with conventional latices with RFL systems.
232/425
[0008] For the production of the carrier materials so obtained and activated for adhesion to
peroxide vulcanizable rubber mixtures, several successive dip cycles or immersion cycles are often
necessary.
[0009] Accordingly, the present invention provides a composition which enables a HNBR rubber
to be vulcanized directly onto the carrier material in question without having to pretreat the
reinforcing material.
SUMMARY OF THE INVENTION
[0010] The present invention is directed to a composition containing
[0011] a) from 0.1 to 99.4 wt. % of a HNBR rubber,
[0012] b) from 0.1 to 20 wt. % of a peroxide crosslinking system and
[0013] c) from 0.5 to 40 wt. % of a resorcinol-formaldehyde resin.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The HNBR rubber of the composition according to the present invention can have a nitrile
group content of from 10 to 50 wt. %.
[0015] The composition according to the present invention can also contain further fillers and
additives.
[0016] The composition according to the present invention can contain, in addition to the further
fillers and additives, also from 0 to 40 wt. % of metal acrylates and/or methacrylates.
[0017] The present invention also provides a process for the preparation of the composition
according to the present invention, wherein components a), b) and c) are mixed.
[0018] There is also provided a process for the production of a composite, wherein the
composition according to the present invention is vulcanized with a carrier material.
[0019] In the process for the production of a composite, the carrier material can be in the form of a
fabric or cord selected from the group consisting of polyamide, polyester, polyaramid, rayon or glass.
[0020] The present invention also provides a composite obtainable by vulcanization of the
composition according to the present invention and the carrier material.
[0021] The composite obtainable by vulcanization of the composition according to the present
invention and the carrier material can be selected from the group consisting of toothed belts, V-belts,
conveyor belts, hoses, bags, membranes, tires, pneumatic springs and rubber muscles.
[0022] The composition according to the present invention contains from 0.1 to 99.4 wt. % of a
HNBR rubber. Preference is given to from 20 to 70 wt. %, more preferably from 30 to 60 wt. %. The
expression HNBR rubber is here to be understood as meaning simple HNBR rubbers as well as
carboxylated HNBR rubbers (HXNBR) and also hydrogenated HNBR copolymers of butadiene,
233/425
acrylonitrile and further acrylic or vinyl monomers. The HNBR rubbers are a highly hydrogenated
nitrile-butadiene or nitrile-butadiene copolymer rubber. Highly hydrogenated is understood as
meaning a content of double bonds in the HNBR rubber that is less than 40 double bonds per 1000
carbon atoms, preferably less than 15 per 1000 carbon atoms, more preferably in the range from 0.2
to 15 double bonds per 1000 carbon atoms. The HNBR rubber for the composition according to the
present invention preferably has a nitrile group content in the range of from 10 to 50 wt. %, preferably
in the range of from 15 to 39 wt. %, more preferably in the range of from 20 to 36 wt. %, based on the
total content of the HNBR rubber.
[0023] The partial and/or complete hydrogenation of a NBR rubber is described in DE-A 2 539 132,
DE-A 3 329 974, DE 3 056 008, DE-A 3 046 251, EP-A 111 412 and WO-A 01/77185. The HNBR
rubber is prepared in solution, which is later converted into solid rubber.
[0024] The nitrile-butadiene rubber used to produce the HNBR rubber preferably has a random
distribution of the monomer units. Suitable monomers for the production of the NBR rubber are all
unsaturated monomers known to the person skilled in the art that are copolymerizable in emulsion
with acrylonitrile and butadiene. Preference is given to copolymers based on acrylonitrile and
butadiene and on acrylonitrile, butadiene, vinyl monomers and acrylate or methacrylate esters and
their free acids.
[0025] Preferred unsaturated monomers for the copolymerization include vinylbenzenes such as
styrene, divinylbenzene, methylstyrene, methacrylonitrile, acrylates such as methyl acrylate, ethyl
acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methacrylates, such as methyl methacrylate, ethyl
methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and their free acids, acrylic acid,
methacrylic acid, maleic anhydride, fumaric acid and itaconic acid.
[0026] The composition according to the present invention contains from 0.1 to 20 wt. %,
preferably from 3 to 15 wt. %, of a peroxide crosslinking system. The peroxide crosslinking system
contains a free-radical generator, preferably in combination with an activator. The proportion of
activator in the crosslinking system as a whole is from 0 to 95 wt. %, preferably from 20 to 70 wt. %.
The proportion of free-radical generator in the crosslinking system as a whole is in the range from 5
to 100 wt. %, preferably in the range from 30 to 80 wt. %. There may be used as activators, for
example, triallyl isocyanurate and triallyl cyanurate, di- and tri-acrylates, cis-1,2-polybutadiene, mN',N-phenylenedimaleimide and others. Preference is given to triallyl isocyanurate, triallyl cyanurate
and trimethylol-propane trimethacrylate.
[0027] There are used as free-radical generators those compounds whose 10-hour half-life in
benzene is over 80[deg.] C. Preference is given to peroxide free-radical generators, such as, for
example, di-tert.-butyl peroxide, di-tert.-butylperoxyiso-propylbenzene, dibenzoyl peroxide, tert.butylcumyl peroxide and others.
234/425
[0028] The composition according to the invention also contains from 0.5 to 40 wt. %, preferably
from 3 to 15 wt. %, of a resorcinol-formaldehyde resin. The resorcinol-formaldehyde resin is a direct
adhesive agent which can be obtained as the condensation product of phenol derivatives with
formaldehyde and/or formaldehyde donors. Preferred resorcinol-formaldehyde resins include, for
example, products such as Bondingagent R6(R) from Uniroyal, products from the product family
Cohedur(R) and Vulkadur(R) from Bayer AG. Resorcinol is preferably used as the phenol or phenol
derivative component. Compounds such as hexamethoxymethylmelamine are frequently used as the
formaldehyde component. The resorcinol-formaldehyde system can be used either in the form of the
individual components (e.g. Cohedur RL(R) from Bayer AG) or in precondensed form (e.g. Vulkadur
T). The reactivity and the adhesion properties can be further influenced by the addition of suitable
catalysts (silica such as e.g. Vulkasil A1(R) (semi-active precipitated aluminum sodium silicate, pH
10-12, surface area 60 m /g), Vulkasil N1(R) (active precipitated silica, pH 7, surface area 130 m /g)
from Bayer AG). The composition according to the present invention can contain from 0 to 75 wt. %
of further fillers and additives. These are preferably used in an amount of from 5 to 75 wt. %, more
preferably in an amount of from 30 to 60 wt. %, based on the total composition of the composition
according to the present invention. Fillers and additives are understood as being any fillers and
additives known to the person skilled in the art which are used in the field of vulcanized rubber
composites and described in Handbuch fьr die Gummiindustrie, 2nd Edition, 1991, published by
Bayer AG. Preference is given to carbon black, silica, inorganic oxides, stabilizers, plasticizers,
processing aids, anti-ageing agents.
[0029] From 0 to 40 wt. %, preferably from 5 to 30 wt. %, based on the total composition of the
composition according to the present invention, of further metal acrylates and/or methacrylates are
preferably added to the composition according to the invention. Preferred metal (meth)acrylates are
zinc diacrylates and zinc dimethacrylates.
[0030] For the preparation of the composition according to the present invention, components a),
b) and c) are mixed together. Apparatuses known to the person skilled in the art, such as internal
mixers and rollers, are used for the mixing. The preparation of the mixture is carried out at
temperatures known to the person skilled in the art. A temperature range of from 40 to 140[deg.] C. is
preferred.
[0031] The present invention also provides a process for the production of a composite from a
carrier material and the composition according to the present invention.
[0032] The carrier material is understood as being any fabrics and cords that are composed of a
fiber material. The fiber material is selected from the group consisting of cotton, rayon, polyamide
fibers such as polycaprolactam, poly(decamethylenecarboxamide) poly(hexamethyleneadipamide
and others), polyaramid fibers (poly(m)-phenyleneisophthalamide), poly(p)-phenyleneisophthalamide
235/425
and others), polyester fibers such as polyethylene terephthalate, polybutylene terephthalate,
poly(cyclohexane 1,4-dimethylene terephthalate and others, glass fibers, steel cord. Preference is
given to fiber materials composed from the group consisting of polyamide, polyester, polyaramid,
rayon and glass.
[0033] For the production of such composites, the composition according to the present invention
is vulcanized with the carrier material at temperatures in the range of from 120 to 220[deg.] C.,
preferably from 150 to 200[deg.] C., and at a pressure of from 0.5 to 50 bar, preferably in the range
of from 2 to 20 bar. The vulcanization is carried out in presses known to the person skilled in the art,
which determine the shape of the composite that is obtained.
[0034] There can be produced a composite selected from the group consisting of tires, conveyor
belts, belts of all kinds, such as toothed belts, V-belts, reinforced hoses, such as fire-extinguishing
hoses, rubberized fabrics, pneumatic springs and rubber muscles.
[0035] The composites so obtained are distinguished by good adhesion between the carrier
material and the rubber even on ageing. The resulting composites have good resistance to heat and
oil and good mechanical properties, such as tensile strength and elongation at break. These
composites have the advantage over conventional composites that they are simple, more rapid and
more economical to produce, because an expensive dipping process for pretreating the carrier
material is unnecessary.
EXAMPLES
[0036] Comparison mixtures not in accordance with the invention and comparison examples
resulting therefrom are marked with #.
TABLE 1
Recipe for different formulations for use as an adhesive mixture for
reinforcing materials. The constituents of the mixture are given in parts
based on the total amount of HNBR rubber (Therban) used.
Constituents of the mixture12345678#9#
Therban VP KA 8889 100100-10101010-10
Therban C3446 --1009090909010090
Rhenofit DDA-70 222222222
Corax N 550 303030303030303030
Cohedur RL 151515510155-Sartomer SR 633 ------30-Struktol ZP1014 66------Aluminum stearate -4-------
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Stearic acid -1.51-----PERKADOX 14-40 B-gr --4555555
[0037] Therban VPKA 8889 from Bayer (hydrogenated acrylonitrile-butadiene-methacrylic acid
terpolymer (HXNBR))
[0038] Therban C3446 from Bayer (hydrogenated acrylonitrile-butadiene copolymer (HNBR))
[0039] Rhenofit DDA-70 from Rheinchemie (70% diphenylamine derivative (dry-liquid))
[0040] Corax N 550 carbon black, FEF fast extruding furnace from Degussa
[0041] Cohedur RL 45.5% resorcinol, 45.5% Cohedur A 700, 9% dibutyl phthalate from Bayer
[0042] Sartomer Saret S633 from Cray, metal diacrylate with added retarding agent
[0043] Struktol ZP 1014 from Schill+Seilacher, zinc peroxide approx. 55% dust-free zinc peroxide
provided with dispersant, accelerator for XNBR and HNBR vulcanization
[0044] Aluminum stearate from Riedel de Haen AG
[0045] Tefacid RG from Tefac (stearic acid)
[0046] Perkadox 14-40 B-gr DI-(TERT.-BUTYL-PEROXY-ISOPROPYL)-benzene 40% from AkzoNobel
[0047] For the preparation of the mixture, the constituents are mixed on a mixing roller in the
following sequence: rubber, carbon black, zinc diacrylate, stabilizers, peroxide and processing aids.
The roller has a temperature of 60[deg.] C.
TABLE 2
Results of physical tests of the properties
of the mixtures prior to vulcanization
Mixture
12345678#9#
Start of vulcanization47.68.8>50>50>50>50>50>50>50
According to DIN 53523
TS 5/120[deg.] C. (min)
[0048]
TABLE 3
Results of physical tests of the properties of the vulcanite's of the
composition without reinforcing materials at room temperature.
Vulcanization was carried out at 180[deg.] C. for 20 minutes at 30 bar.
Tensile test accordingMixture
to DIN 5350412345678#9#
Tensile strength (MPa)28.8322323.721.920.727.92827.2
Elongation at break (%)221265517489468461290507519
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Modulus at 50%5.35.01.41.21.31.44.81.21.2
elongation (MPa)
Modulus at 100%12.11121.92.12.110.11.81.9
elongation (MPa)
Modulus at 200%26.5265.45.86.56.221.85.65.7
elongation (MPa)
Modulus at 300%--10.812.212.812.3-12.111.9
elongation (MPa)
Tear strength according12.613.513.217.111.812.7
to DIN 53515 (N)
Hardness measurement828263606163845959
(3 * 2 mm rod)
according to DIN
53505 (Shore A)
[0049]
TABLE 4
Results of the tests of adhesion to various textile fabrics. The peel
strength was determined at 23[deg.] C. according to DIN 53530 at a take-off
speed of 100 mm/min. The peel strengths of mixtures 1 to 9 from a
polyamide fabric, from the same polyamide fabric coated with
commercial HNBR-RFL latex and from a rayon fabric were tested on
the peel test specimens described in DIN 53530. The specimens were
vulcanized at 180[deg.] C. for 30 minutes at 30 bar.
Mixture
12345678#9#
Peel strength
N/25 mmN/10 mm
Polyamide fabric157*220*384*125*126*110*61** 8** 5**
Untreated
Polyamide fabric 13.4** 17.8** 94**
coated with RFLHNBR
Rayon fabric 43** 49** 50**25**25**26**
Untreated
*breakage of the rubber
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**breakage at the point of transition between the fabric and the mixture
[0050] Although the invention has been described in detail in the foregoing for the purpose of
illustration, it is to be understood that such detail is solely for that purpose and that variations can be
made therein by those skilled in the art without departing from the spirit and scope of the invention
except as it may be limited by the claims.Claims:
1. Composition comprising
a) from 0.1 to 98.4 wt. % of a HNBR rubber,
b) from 0.1 to 20 wt. % of a peroxide crosslinking system and
c) from 0.5 to 40 wt. % of a resorcinol-formaldehyde resin.
2. The composition according to claim 1, wherein the HNBR rubber has a nitrile group content of
from 10 to 50 wt. %.
3. The composition according to claim 1, wherein the composition can also contain further fillers and
additives.
4. The composition according to claim 3, further comprising from 0 to 40 wt. % of metal acrylates
and/or methacrylates.
5. Process for the preparation of the composition according claim 1, comprising mixing components
a), b) and c).
6. Process for the production of a composite comprising vulcanizing the the composition according
to claim 1 with a carrier material.
7. The process according to claim 6, wherein the carrier material is selected from the group
consisting of polyamide, polyester, polyaramid, rayon and glass.
8. Composite prepared by vulcanizing the composition according to claim 1 and a carrier material.
9. The composite according to claim 8, wherein the composite is selected from the group consisting
of toothed belts, V-belts, conveyor belts, coated fabrics, hoses, bags, tires, pneumatic springs and
rubber muscles.
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26. KR2002023682 - 29.03.2002
COMPOSITE MATERIAL SHEET FOR PREVENTING ADHESION OF NON-VULCANIZED RUBBER
AND PROCESS FOR PRODUCING THE SAME
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=KR2002023682
Inventor(s):
HWANG SU DEOK [KR] (--); NA JONG BOK [KR] (--)
Applicant(s):
KM and E CO LTD [KR] (--)
IP Class 4 Digits: C08J
IP Class:
C8J5/18
Application Number:
KR20010074776 (20011128)
Priority Number: KR20010074776 (20011128)
Family: KR2002023682
240/425
27. KR2003034552 - 09.05.2003
METHOD FOR REPAIRING PIPELINE BY USING VISCOUS NON-VULCANIZED RUBBER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=KR2003034552
Inventor(s):
LEE DAE WOO [KR] (--)
Applicant(s):
LEE DAE WOO [KR] (--)
IP Class 4 Digits: F16L
IP Class:
F16L55/16
Application Number:
KR20010066177 (20011026)
Priority Number: KR20010066177 (20011026)
Family: KR2003034552
241/425
28. RU2193579 - 27.11.2002
VULCANIZED RUBBER STABILIZER BASED ON UNSATURATED RUBBERS (OPTIONS)
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=RU2193579
Inventor(s):
GOTLIB E M (--); GRINBERG L P (--); LIAKUMOVICH A G (--); ZHARIKOV L K (--);
KAVUN S M (--); LOGUTOV I JU (--); KHISMATULLIN S G (--)
Applicant(s):
BOTKE EHLASTOMEROV (--); O PROMY PRED TSENTRA RAZRA (--)
IP Class 4 Digits: C08K; C08L
IP Class:
C8K5/00; C8K5/13; C8L9/00; C8L79/00
Application Number:
RU20010104253 (20010213)
Priority Number: RU20010104253 (20010213)
Family: RU2193579
Abstract:
FIELD: RUBBER INDUSTRY. SUBSTANCE: STABILIZER CONTAINS 50-70% INTERACTION
PRODUCT OF BUTYLPHENOL MIXTURE (WT %: 2,6-DI-T- BUTYLPHENOL 0.5-2.0, 2,4-DI-TBUTYLPHENOL 22-75, 2,4,6-TRI-T-BUTYLPHENOL 14-61, MONO- AND DISUBSTITUTED
BUTYLPHENOLS 10.5-15.0) WITH HEXAMETHYLENETETRAMINE AT WEIGHT RATIO 100:(4-6) AND
30-50% MIXTURE OF 6-ETHOXYSUBSTITUTED QUINOLINES (WT %: 6-ETHOXY-2,2,4-TRIMETHYL1,2- DIHYDROQUINOLINE 5-20, 6-ETHOXY-2,4-DIMETHYLQUINOLINE 15-20, N-ACETYL-6ETHOXY- 2,2,4-TRIMETHYL-1,2-DIHYDROQUINOLINE 50-55, AND RESIN BASED ON 6ETHOXYSUBSTITUTED QUINOLINES 5-30). STABILIZER CAN FURTHER CONTAIN POLYMER OF
2,2,4- TRIMETHYL-1,2-DIHYDROQUINOLINE. IN THIS CASE STABILIZER CONTAINS 5-25% OF
THIS POLYMER, 50-70% OF ABOVE-INDICATED INTERACTION PRODUCT, AND 15-35% OF
QUINOLINE MIXTURE. EFFECT: INCREASED RESISTANCE TO SCORCHING OF RUBBER
COMPOUNDS, REDUCED VISCOSITY OF THE LATTER, AND INCREASED THEIR PLASTICITY. 2 CL,
4 TBL, 10 EX
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29. RU2203291 - 27.04.2003
COMPOSITE FOR SURFACE TREATMENT OF VULCANIZED RUBBER
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=RU2203291
Inventor(s):
ARTAMONOVA E A (--); GALINSKIJ S S (--); TIKHONOV V D (--); ROZOV N A (--);
KHINSKAJA O V (--); KHOROSHEVA V V (--)
Applicant(s):
TSENTRAL NYJ NII T SUDOSTROENI (--); FEDERAL NOE GUP (--)
IP Class 4 Digits: C08J; C08L
IP Class:
C8L9/00; C8J7/12
Application Number:
RU20010121447 (20010730)
Priority Number: RU20010121447 (20010730)
Family: RU2203291
Abstract:
FIELD: RUBBER INDUSTRY AND TECHNOLOGY. SUBSTANCE: INVENTION RELATES TO
COMPOSITES USED FOR SURFACE TREATMENT OF VULCANIZED RUBBER IN GLUING AND
SEALING RUBBER WITH POLYURETHANE SEALING AGENT. COMPOSITE COMPRISES THE
FOLLOWING COMPONENTS, MAS. P. P.: N-HALOGEN- SULFAMIDE OF THE STRUCTURE
FORMULA (I) WHERE R IS HYDROGEN ATOM, CH3, CHLORINE ATOM, 8-16; ETHYL ACETATE, 3090; BENZINE, 10-50; EPOXY DIANE NON-HARDENED RESIN ED-20, 4-16. FIRSTLY, ETHYL
ACETATE IS MIXED WITH BENZINE, THEN N-HALOGENSULFAMIDE IS ADDED AND DISSOLVED
ITS. THEN ED-20 IS ADDED, STIRRED UP TO DISSOLUTION, KEPT FOR 30 MIN AND APPLIED ON
PREPARED RUBBER. GLUING TREATED RUBBER IS CARRIED OUT WITH POLYURETHANE COLD
HARDENING SEALING AGENT. INVENTION PROVIDES ENHANCEMENT OF ADHESION
STRENGTH IN GLUING VULCANIZED RUBBER WITH POLYURETHANE SEALING AGENT BASED
ON SKU-DF-2. INVENTION CAN BE USED IN SHIP BUILDING, RUBBER INDUSTRY AND OTHER
BRANCHES. EFFECT: IMPROVED AND VALUABLE PROPERTIES OF COMPOSITE. 2 TBL
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30. WO03016028 - 02.06.2004
PROCESS FOR PRODUCTION OF VULCANIZED RUBBER-RESIN COMPOSITES
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO03016028
Inventor(s):
HAGA HIROAKI (JP)
Applicant(s):
NOK CORP (JP)
IP Class 4 Digits: B29C
IP Class:
B29C45/14; B29C65/70
E Class: B29C45/14Q; C08J5/12H6
Application Number:
EP20020755840 (20020806)
Priority Number: WO2002JP07994 (20020806); JP20010243184 (20010810)
Family: WO03016028
Equivalent:
US2004113313
Cited Document(s):
EP0627456; US3826772; US3258389
Abstract:
IN THE PRODUCTION OF A VULCANIZED RUBBER-RESIN COMPOSITE MATERIAL BY PROVIDING
A VULCANIZED RUBBER MOLDING IN A MOLD, FOLLOWED BY INJECTING A RESIN INTO THE
MOLD, A VULCANIZABLE ADHESIVE LAYER CONTAINING BROMINATED POLY(2,3DICHLOROBUTADIENE-1,3) AS THE MAIN COMPONENT IS FORMED ON THE SURFACE TO BE
BONDED OF THE VULCANIZED RUBBER MOLDING, AND THEN INJECTING THE RESIN WHILE
KEEPING THE VULCANIZABLE ADHESIVE LAYER TO STAY AS FORMED ON THE SURFACE TO BE
BONDED, THEREBY EFFECTING THE BONDING, WHERE A STRONG ADHESION IS ESTABLISHED
BETWEEN THE VULCANIZED RUBBER MOLDING AND THE RESIN LAYER WITHOUT ANY HEAT
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TREATMENT OF THE VULCANIZED RUBBER MOLDING BEFORE PROVISION OF THE
VULCANIZED RUBBER MOLDING IN THE MOLD OR WITHOUT ANY HEAT TREATMENT OF THE
COMPOSITE MATERIAL AFTER THE RESIN INJECTION.Description:
TECHNICAL FIELD
[0001] The present invention relates to a process for producing a vulcanized rubber-resin
composite material and more particularly to a process for producing a vulcanized rubber-resin
composite material with a considerably improved bonding strength.
BACKGROUND ART
[0002] Engineering plastics have distinguished characteristics such as a high mechanical strength,
a high creep resistance, etc. and thus are widely used in various fields as a substitute for metals.
Even in the fields of industrial rubber products and automobile vibration-absorbing rubber products,
formation of rubber-resin composite materials based on resins has been now in progress.
[0003] Conventional processes for producing rubber-resin composite materials such as rubberbushed plastic rods, bushes, engine mounts, etc. include a process, which comprises applying a
rubber-based adhesive to resin moldings, followed by vulcanization bonding to an unvulcanized
rubber, but the process suffers from such problems as occurrence of deformation or physical
property degradation of the resin moldings due to the mold-inside heat, a prolonged time for
elevating the temperature of resin moldings up to a necessary temperature for the vulcanization and
an inevitable production cost increase due to a longer time than that required for the vulcanization of
metal-rubber.
[0004] As one of the processes applicable to production of the aforementioned bushed plastic
rods, a process, which comprises providing a vulcanized rubber molding in a mold, followed by
injection molding a molten resin into the mold (JP-B-7-55510), where the desired surface of the
vulcanized rubber molding for bonding to the resin is subjected to a treatment according to a
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method (1) comprising a chlorination and application of a vulcanizable adhesive containing a resol
type phenol resin and an aldehyde-modified polyvinyl alcohol as the main components or according
to a method (2) comprising application of a vulcanizable adhesive containing chlorosulfonated
polyethylene as the main component.
[0005] The above-mentioned method (1) suffers not only from diffusion of an organic solvent used
in the chlorination into the atmosphere and an influence on workers or a cost increase in firepreventive facility, etc. due to the use of the organic solvent, but also from a fear of development of
crack generation-starting points when a shearing force is applied to the chlorinated vulcanized
rubber molding itself. The method (2) requires a heat treatment (prebaking) of the adhesive-applied
vulcanized rubber molding in advance to the injection of the molten resin into the mold and also
requires a heat treatment of the vulcanized-resin composite material after the injection. No stable
quality bonding can be obtained unless such a heat treatment is carried out fully.
DISCLOSURE OF THE INVENTION
[0006] An object of the present invention is to provide a process for producing a vulcanized
rubber-resin composite material by providing a vulcanized rubber molding in a mold, followed by
injecting a resin into the mold, the process being capable of establishing a strong adhesion between
the vulcanized rubber molding and the resin layer without any heat treatment before the provision of
the vulcanized rubber molding in the mold or without any heat treatment of the composite material
after the resin injection.
[0007] In the process for producing the aforementioned complex, the object of the present
invention can be attained by forming a vulcanizable adhesive layer containing brominated poly(2,3dichlorobutadiene-1,3) as the main component on the surface to be bonded of the vulcanized rubber
molding, and then injecting the resin into the mold while keeping the vulcanizable adhesive layer to
stay as formed on the surface to be bonded, thereby effecting the bonding.
[0008] The vulcanized rubber molding to be provided in the mold in advance is at least one of
vulcanized moldings of various synthetic rubbers and natural rubber, where the rubber components
are not particularly limited, but those with carbon-carbon double bonds in the molecules are
preferable. Synthetic rubbers include, for example, butadiene rubber, isoprene rubber, butyl rubber,
246/425
NBR, SBR, EPDM, etc. These rubber components are properly blended with a filler such as carbon
black, silica, calcium carbonate, graphite, etc., an antioxidant, a lubricant, a vulcanizing agent, a
vulcanization additive, a vulcanization accelerator, etc., followed by thorough kneading by the
ordinary kneading method and subsequently vulcanization molding in any vulcanization mold kept
ready in advance under appropriate vulcanization conditions depending on the kind of the rubber
components.
[0009] A vulcanizable adhesive containing brominated poly(2,3-dichlorobutadiene-1,3) as the main
component, as dissolved or dispersed in an organic solvent, is applied to the surface to be bonded
of the vulcanized rubber molding by any method such as brush coating, spraying, dipping, etc. to
form a vulcanizable adhesive layer thereon to a thickness of about 5-about 50 mu m.
[0010] Brominated poly(2,3-dichlorolbutadiene-1,3) is a well known substance obtained by
brominating poly(2,3-dichlorobutadiene-1,3). For example, Japanese Patent No. 2,927,369 (WO
95/18835) or US Patent No. 5,534,591 discloses use of poly(2,3-dichlorobutadiene-1,3) containing 23
wt.% Br as a film-formable component of a chlorinated polyolefin adhesive composition for bonding a
metal to an elastomer material. In the present invention, brominated poly(2,3-dichlorobutadiene-1,3)
containing about 10-about 27 wt.% Br is used, but practically commercially available organic solvent
types, for example, Chemlock 225, a product of LOAD Co., etc. can be used as such.
[0011] Resin is injected into the mold provided with the vulcanized rubber molding, on which a
vulcanizable adhesive layer is previously formed by aforementioned method, and bonded thereto
through the vulcanizable adhesive layer formed thereon. The resin to be injected includes, for
example, polyamide, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate,
etc., and preferable for use is a polyamide resin having amide bonds in the main chain. Furthermore,
to improve the mechanical strength characteristic of the resin itself, a reinforcing agent such as glass
fibers, carbon fibers, whiskers, etc., a filler such as carbon black, silica, calcium carbonate, etc. can
be added to the resin within such a range as not to deteriorate the processability, practically in a
proportion of not more than about 60 wt.%.
BEST MODE FOR CARRYING OUT THE INVENTION
[0012] The present invention will be described below, referring to Examples.
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EXAMPLE 1
Columns=2
Natural rubber100 parts by weight
FEF carbon black20 "
Zink white5 "
Stearic acid1 "
Plaslicizer (naphthene series oil)5 "
Antioxidant (Nocrac 3C, a product by Ouchi-Shinko Kagaku K.K.)2.5 "
" (Nocrac 224, ditto)2.5 "
Sulfur1.5 "
Vulcanization acceleralator (NOCCELER TS, a product by Ouchi-Shinko Kagaku K.K.)2 "
[0014] A test piece in the size of 17x80x7.5 mm was made from a natural rubber composition
comprising the aforementioned blend components by vulcanization molding. The test piece was in
such a shape that the upper right half portion (17x40x3 mm) was cut away.
[0015] A vulcanizable adhesive (Chemlock 225, a product by LOAD Co.) containing brominated
poly(2,3-dichlorobutadiene-1,3) was applied to the to-be-bonded test piece surface corresponding
to the cut-away portion, followed by providing the test piece in a mold without prebaking and
injection molding molten nylon-6,6 (filled with 50% glass fibers) therein, thereby bonding the test
piece surface corresponding to the cut-away portion to the molten nylon-6,6.
EXAMPLE 2
[0016] In Example 1, molten polyethylene terephthalate (filled with 30% glass fibers) was used in
place of the molten nylon-6,6 (filled with 50% glass fibers).
EXAMPLE 3
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[0017] In Example 1, natural rubber/butadiene rubber (in a weight ratio of 70/30) blend rubber was
used in the same amount in place of the natural rubber.
EXAMPLE 4
[0018] In Example 1, SBR was used in the same amount in place of the natural rubber.
COMPARATIVE EXAMPLE 1
[0019] In Example, a vulcanizable adhesive containing chlorosulfonated polyethylene as the main
component (Chemlock 252, a product by LOAD Co.) was used.
COMPARATIVE EXAMPLE 2
[0020] In Comparative Example 1, a vulcanized molding subjected to a prebaking treatment at 120
DEG C for 30 minutes was used.
COMPARATIVE EXAMPLE 3
[0021] In Comparative Example 2, the resulting composite material was subjected to a heat
treatment at 120 DEG C for 60 minutes.
[0022] The composite materials prepared in the foregoing Examples and Comparative Examples
were subjected to determination of bonding strength according to 90 DEG peeling test procedure
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of JIS K-6256, determination of rubber retention and observation of broken state. The results are
shown in the following Table.
Id=Table Columns=4
Head Col 1: Example
Head Col 2: Bonding strength
(KN/m)
Head Col 3: Rubber retention (%)
Head Col 4: Broken state
Example 114.5100Thick rubber layer was retained
Example 214.5100"
Example 313.0100"
Example 411.5100"
Comp.Ex.18.560Thin rubber layer was retained
Comp.Ex.212.385"
Comp.Ex.314.295"
INDUSTRIAL APPLICABILITY
[0023] According to the present process, vulcanized rubber-resin composite materials in firm and
stable bonding between vulcanized rubber moldings and resins can be easily produced at a low
cost without such a chlorination treatment or a heat treatment as in the conventional process. As to
the heat treatment, in the case of using a vulcanizable adhesive containing chlorosulfonated
polyethylene as the main component, no satisfactory adhesion is obtained without prebaking of
vulcanized rubber moldings prior to the resin injection or without heat treatment of the composite
materials after the injection, whereas in the present process vulcanized rubber-resin composite
materials with satisfactory adhesion and bonding strength can be obtained without prebaking prior to
the resin injection and without heat treatment after the resin injection.
[0024] The present process with such features can be effectively used in the production of
automobile bushes, engine mounts, etc.Claims:
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1. A process for producing a vulcanized rubber-resin composite material by providing a vulcanized
rubber molding in a mold, followed by injecting a resin into the mold, characterized by forming a
vulcanizable adhesive layer containing brominated poly(2,3-dichlorobutadiene-1,3) as the main
component on the surface to be bonded of the vulcanized rubber molding, and then injecting the
resin into the mold while keeping the vulcanizable adhesive layer to stay as formed on the surface to
be bonded, thereby effecting the bonding.
2. A process for producing a vulcanized rubber-resin composite material according to Claim 1,
wherein a vulcanized molding of rubber having carbon-carbon double bonds in the molecule is used
as the vulcanized rubber molding.
3. A process for producing a vulcanized rubber-resin composite material according to Claim 2,
wherein the rubber having carbon-carbon double bonds in the molecule is natural rubber.
4. A process for producing a vulcanized rubber-resin composite material according to Claim 2,
wherein the rubber having carbon-carbon double bonds in the molecule is butadiene rubber,
isoprene rubber, butyl rubber, NBR, SBR or EPDM.
5. A process for producing a vulcanized rubber-resin composite material according to Claim 1,
wherein the resin to be injected is polyamide, polyphenylene sulfide, polyethylene terephthalate or
polybutylene terephthalate.
6. A process for producing a vulcanized rubber-resin composite material according to Claim 5,
wherein the resin to be injected contains a filler.
7. A process for producing a vulcanized rubber-resin composite material according to Claim 1,
wherein neither heat treatment of the vulcanized rubber molding before provision in the mold nor
heat treatment of the composite material after the resin injection is carried out.
8. A process for producing a vulcanized rubber-resin composite material according to Claim 1,
wherein the vulcanized rubber-resin composite material is directed to an automobile bush or an
engine mount.
251/425
31. WO03050173 - 26.06.2003
COLORED ANTIMICROBIAL VULCANIZED RUBBER ARTICLES
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO03050173
Inventor(s):
PATEL BHAWAN (GB); MORRIS DAVID L (GB); HAAS GEOFFREY (US); BURKE
WILLIAM O (US)
IP Class 4 Digits: C08K; A61L
IP Class:
C8K3/08; A61L2/00; C8K3/34
E Class: C08K3/00P7+L21/00; C08K3/34+L21/00; C08K5/00P7+L23/16
Application Number:
US20010015878 (20011212)
Priority Number: US20010015878 (20011212)
Family: EP1453899
Equivalent:
AU2002337744; BR0214836; EP1453899; US6638993
Abstract:
CERTAIN NON-SILICONE VULCANIZED RUBBER ARTICLES MADE FROM AT LEAST A MAJORITY
BY WEIGHT OF ETHYLENE-PROPYLENE-DIENE MODIFIED (TERPOLYMER) RUBBER (SUCH AS,
WITHOUT LIMITATION, EPDM AND/OR NBR) THAT INCLUDE SILVER-BASED COMPOUNDS TO
PROVIDE HIGHLY DESIRABLE LONG-TERM ANTIMICROBIAL CHARACTERISTICS WITHIN THE
CURED RUBBER ARTICLES, AT LEAST A PORTION OF WHICH EXHIBITS A COLOR OTHER THAN
BLACK, ARE PROVIDED. SUCH ARTICLES ARE IN EITHER SOLID OR BLOWN (FOAM OR SPONGE)
STATE (OR COMBINATIONS OF BOTH IN MULTILAYERED FORMS, EITHER ALL COLORED OR
INDIVIDUAL LAYERS COLORED) THAT CAN BE UTILIZED IN A VARIETY OF DIFFERENT
APPLICATIONS. AS SILVER-BASED COMPOUNDS ARE DELETERIOUSLY AFFECTED BY
UTILIZATION OF STANDARD CURING AGENTS AND CURING ACCELERATORS, SUCH AS
SULFUR-BASED COMPOUNDS AND/OR SYSTEMS, THE ABILITY TO PROVIDE SUCH AN
252/425
EFFECTIVE ANTIMICROBIAL VULCANIZED RUBBER ARTICLE IS RATHER DIFFICULT. HOWEVER,
THIS INVENTION ENCOMPASSES THE PRESENCE OF DIFFERENT NON-SULFUR-BASED CURING
SYSTEMS AND AGENTS, SUCH AS PEROXIDES, AS ONE EXAMPLE, THAT PERMIT
VULCANIZATION AND DO NOT IRREVERSIBLY BIND SILVER IONS THERETO, THEREBY
RESULTING IN LONG-TERM ANTIMICROBIAL PERFORMANCE OF THE ULTIMATE RUBBER
ARTICLE ITSELF. THE RUBBER ARTICLES MUST ALSO COMPRISE FILLERS AND MAY ALSO
INCLUDE PLASTICIZERS TO PROVIDE DESIRED CHARACTERISTICS OF DIMENSIONAL STABILITY,
STIFFNESS, FLEXURAL MODULUS, TENSILE STRENGTH, ABRASION RESISTANCE, ELONGATION,
AND THE LIKE, FOR THE ULTIMATE RUBBER ARTICLE, WHILE SIMULTANEOUSLY AND
SURPRISINGLY BOTH ENHANCING THE CONTROL OF ANTIMICROBIAL EFFICACY OF THE
RUBBER ARTICLE AND NOT DELETERIOUSLY BINDING TO THE AVAILABLE SILVER TO PERMIT
COLORING OF THE TARGET RUBBER AS WELL.Description:
FIELD OF THE INVENTION
[0001] This invention relates to certain non-silicone vulcanized rubber articles made from at least a
majority by weight of rubber (such as, without limitation, ethylene-propylene diene modified rubber,
a.k.a., EPDM, and/or acrylonitrile butadiene rubber, aka, NBR) that include silver-based compounds
to provide highly desirable long-term antimicrobial characteristics within the cured rubber articles, at
least a portion of which exhibits a color other than black. Such articles are in either solid or blown
(foam or sponge) state (or combinations of both in multilayered forms, either all colored or individual
layers colored) that can be utilized in a variety of different applications. As silver-based compounds
are deleteriously affected by utilization of standard curing agents and curing accelerators, such as
sulfur-based compounds and/or systems, the ability to provide such an effective antimicrobial
vulcanized rubber article is rather difficult. However, this invention encompasses the presence of
different non-sulfur-based curing systems and agents, such as peroxides, as one example, that
permit vulcanization and do not irreversibly bind silver ions thereto, thereby resulting in long-term
antimicrobial performance of the ultimate rubber article itself. The rubber articles must also comprise
fillers and may also include plasticizers to provide desired characteristics of dimensional stability,
stiffness, flexural modulus, tensile strength, abrasion resistance, elongation, and the like, for the
ultimate rubber article, while simultaneously and surprisingly both enhancing the control of
antimicrobial efficacy of the rubber article and not deleteriously binding to the available silver to
permit coloring of the target rubber as well.
DISCUSSION OF THE PRIOR ART
[0002] All U.S. Patents listed below are herein entirely incorporated by reference.
253/425
[0003] There has been a great deal of attention in recent years given to the hazards of bacterial
contamination from potential everyday exposure. Noteworthy examples of such concerns include the
fatal consequences of food poisoning due to certain strains of Eschericia coli being found within
undercooked beef in fast food restaurants; Salmonella enteritidis contamination causing sicknesses
from undercooked and unwashed poultry food products; and illnesses and skin infections attributed
to Staphylococcus aureus, Klebsiella pneumoniae, yeast (Candida albicans), and other unicellular
organisms. With such an increased consumer interest in this area, manufacturers have begun
introducing antimicrobial agents within various everyday products and articles. For instance, certain
brands of cutting boards, shoe soles, shoe inserts, medical devices and implements, liquid soaps,
etc., all contain antimicrobial compounds. The most popular antimicrobial for such articles is triclosan.
Although the incorporation of such a compound within liquid or certain polymeric media has been
relatively simple, other substrates, specifically vulcanized rubber and surfaces thereof, have proven
less accessible. Furthermore, such triclosan additives have proven to be difficult in use or ineffective
for certain bacteria. For instance, triclosan itself migrates easily within and out of certain polymeric
substrates and/or matrices (and thus is not very durable), lacks thermal stability (and thus readily
leaches out of rubber and like materials at higher temperatures), and does not provide a wide range
of bacterial kill (for instance does not exhibit any kill for Pseudomonas aeruginosa).
[0004] Antimicrobial rubber formulations are certainly highly desired for the production of vulcanized
rubber articles and compositions to provide not only antibacterial benefits, but also antifungal,
antimildew, antistaining, and odor control properties. Rubber articles are utilized in many different
applications, from automobiles (hoses, tires, bumpers, etc.), to household items (toys, sink washers,
gaskets, appliances, floor mats, door mats, seals, carpeted rubber mats, gloves, and the like), and
other areas in which bacterial growth is a potential problem. There thus remains a long-felt need to
provide an effective, durable, reliable antimicrobial vulcanized rubber formulation which will provide
such long-term antimicrobial, etc., effects within the final vulcanized article. Unfortunately, such a
highly desired antimicrobial rubber formulation and/or vulcanized article containing silver-based
antimicrobial agents has heretofore not been provided by the pertinent prior art.
[0005] The closest art includes Japanese Patent Application 1997-342076 which discloses the
production of unvulcanized rubber formulations and articles exhibiting antibacterial properties due to
the presence of silver complexes. Such formulations are formed through high temperature kneading
in an oxygen-free atmosphere and are used as parts in a water disinfection system. Again, no
vulcanized rubber is taught or obtained within or through this disclosure. Antimicrobial rubber bands
have been taught in Japanese Patent Application 1997-140034 in vulcanized form with silver
antimicrobials therein. However, such compounds are rather limited in use and the vulcanization step
must include a sulfur curing agent to effectuate the final vulcanized arrangement of the subject
254/425
rubber. Such sulfur curing agents have a remarkably deleterious effect on certain silver-based
antimicrobials such that the sulfur reacts with the silver ion to from silver sulfide, thereby rendering it
ineffective as a bactericide. As such, the utilization of such specific rubber band formulations for and
within large-scale antimicrobial articles is basically unworkable.
[0006] Certain types of antimicrobial peroxide-catalyst vulcanized rubber formulations have been
produced in the past; however, such peroxide-cured rubbers are all silicone-based. It is well
understood and accepted that silicone rubbers cannot be vulcanized by typical sulfur-based
catalysts. Thus, the antimicrobial rubber formulations of Japanese Patent Applications 1997-026273
and 1995-065149 as well as U.S. Pat. No. 5,466,726 are standard vulcanized silicone rubber
formulations and articles which also include certain antimicrobial compounds.
[0007] Furthermore, rubber latexes (non-vulcanized) comprising antimicrobials have been disclosed
(U.S. Pat. No. 5,736,591, for example), as have floor mats having silver-based antimicrobials
incorporated within pile fiber components and which have non-antimicrobial rubber backings cured
through peroxide-catalyzed vulcanization to protect the pile fiber antimicrobial compounds from
attack by any sulfur compounds (as in Japanese Patent Applications 1993-3555168 and 199538991). Again, however, to date there have been no disclosures or suggestions of producing a
vulcanized non-silicone rubber formulation exhibiting excellent antimicrobial properties through the
long-term effective utilization of silver-based antibacterial compounds. This invention fills such a void.
OBJECT OF THE INVENTION
[0008] It is therefore an object of this invention to provide a colored (other than black) antimicrobial
vulcanized rubber-containing article exhibiting sufficient antimicrobial activity and structural integrity
to withstand repeated use without losing an appreciable level of either antimicrobial power or
modulus strength. Another object of the invention is to provide an antimicrobial colored vulcanized
rubber article comprising silver-based antimicrobial compounds which include curing agents which
do not deleteriously effect the antimicrobial activity of the finished vulcanized article (and thus is
essentially free from sulfur-based curing agents and accelerators). Yet another object of this
invention is to provide a colored vulcanized EPDM and/or NBR rubber-containing article that exhibits
log kill rates for Staphylococcus aureus and Klebsiella pneumoniae (and/or other types of bacteria as
well) of at least 1.0 after 24 hours exposure at room temperature as well as prevention of growth of
certain fungi after at least 15 days of exposure. Still another object of this invention is to provide a
vulcanized EPDM and/or NBR rubber-containing article comprising structural integrity filler
components and plasticizers (such as properly formulated silica, certain metal salts, certain organic
salts, calcium carbonate, certain metal oxides, clays, certain oils, and the like) that also provide
enhancements in the control of antimicrobial efficacy of the article itself through regulated silver ion
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release to the article surface (e.g., exhibits higher log kill rates for Staphylococcus aureus and
Klebsiella pneumoniae and prevention of growth of fungi such as Aspergillus niger). Still another
object of the invention is to provide a finished colored rubber article that exhibits increases in
antimicrobial activity after industrial washing and/or abrasion. Yet another object is to provide a
simple method of producing such an antimicrobial colored vulcanized EPDM and/or NBR rubbercontaining article.
[0009] Accordingly, this invention encompasses a dimensionally stable vulcanized rubber-containing
colored article exhibiting log kill rates for Staphylococcus aureus and Klebsiella pneumoniae of at
least 1.0 each after 24 hours exposure at room temperature. Also, this invention encompasses a
dimensionally stable vulcanized rubber-containing article exhibiting antifungal properties such that
said article exhibits at least 70% inhibition in accordance with Test Method ISO 486, of Aspergillus
niger ATCC 6275 for at least 15 days at 30[deg.] C. and at greater than 90% humidity. Furthermore
this invention encompasses such a colored vulcanized rubber-containing article comprising at least
one non-discoloring silver ion control release additive, such as those selected selected from the
group consisting of fillers (such as calcium carbonate, china or calcined clay, silane-coated or mixed
silica, bivalent metal silicates, aluminum trihydrate, and any mixtures thereof), at least one coloring
agent to provide a color to the article other than black, and, optionally, at least one plasticizer (e.g.,
oils such as phthalate oils and paraffinic oils). Additionally, this invention encompasses a method of
producing such a colored vulcanized EPDM and/or NBR rubber-containing article comprising the
steps of providing a rubber formulation comprising uncured rubber, at least one non-sulfur based
curing agent, and at least one silver-based antimicrobial compound, at least one non-discoloring
silver release additive (filler), at least one coloring agent to provide a non-black color to the finished
article, and vulcanizing said rubber formulation at a temperature of at least 150[deg.] C. and at least
at a pressure of 3 bars, wherein said rubber formulation is substantially free from sulfur curing agent
and accelerator.
[0010] The term "dimensionally stable" is intended to encompass a vulcanized rubber article that is
structurally able to be handled without disintegrating into smaller portions. Thus, the article must
exhibit some degree of structural integrity and, being a rubber, a certain degree of flexural modulus.
[0011] The term "colored" is intended, as implied above, to denote a color other than black for the
finished black article. Such an effect provides aesthetic improvements, as well as potential product
identification benefits, to the target rubber article. Without intending on being limited to any specific
scientific theory, the presence of certain fillers within the rubber formulation appears to result in
problematic complexing with the silver ions in the antimicrobial agent. Such a reaction binds the
silver and creates dark discolorations within the rubber itself. With a black pigment (or other colorant)
present, the rubber is not deleteriously discolored with such a resultant reaction between the silver
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ion and the filler (such as, silica, aluminum silicate, and others) since the color of the base rubber
does not dominate the desired black coloration. However, with lighter colors, such as white, red, blue,
yellow, green, orange, and the like, the presence of these fillers tends to create an undesirable
dominant discoloration within the target formulation such that the article would appear black or like
dark-colored; certainly not the same as desired in terms of the target lighter colorations. Thus, there
are important criteria to be met in order to provide the desired colored rubber articles of this
invention, primarily in terms of selection of filler component to not only provide dimensional stability
and substance therein, but also to permit proper coloring of the target rubber article, again, for
predominately aesthetic purposes. To date, again, the ability to provide a colored antimicrobial
rubber with antimicrobial durability and aesthetically pleasing appearance (in terms of color), has
been extremely limited due to the proper selection requirements of an antimicrobial agent, a curing
system, and a filler component, in tandem that will not deleteriously affect the final target rubber
article.
[0012] Thus, such a specific antimicrobial vulcanized rubber-containing article has not been taught
nor fairly suggested within the rubber industry or prior art. As noted above, the avoidance of sulfurbased curing agents and accelerators to any appreciable degree thus permits the retention of silver
antimicrobials within the final product in amounts sufficient to provide long-lasting log kill rates for
Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escheria coli, at the
very least. Furthermore, due primarily to high costs, non-sulfur curing agents have not been prevalent
within vulcanized rubber formulations and articles. As such, there has been no teaching or fair
suggestion of coupling non-sulfur curing agents (and most preferably peroxide curing agents) with
silver-based antimicrobial agents within pre-vulcanized rubber formulations to form effectively
antimicrobial vulcanized rubber articles.
[0013] Additionally, generally and preferably, certain fillers and, supplementally, oils, (such as
bivalent silicates, silane-coated or mixed silica, zinc oxide, clays, aluminum trihydrate salts, calcium
carbonate, and other types that do not discolor silver antimicrobial-containing EPDM and/or NBR, as
merely preferred examples, rubber formulations) are required to provide both flexural modulus and
structural integrity to vulcanized rubber articles. The rubber component alone generally does not
exhibit proper dimensional stability without such additives. Surprisingly, the presence of such
additives also provides the ability to control silver-ion release at the target article surface as well as
lack of deleterious reaction with the desired silver ions within the antimicrobial component present
therein. As such, not only does the target article exhibit acceptable, if not excellent, dimensional
stability subsequent to vulcanization, but also the ability to be colored in bright, pleasing shades
without unwanted complications (and thus darkening) through the aforementioned problematic
potential silver ion-filler reaction. Such an inventive colored durable antimicrobial rubber is thus
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unique and requires selectivity in terms of components therein to achieve. Such beneficial fillers, as
noted above, thus appear to provide a number of important characteristics to, for, and within the
target rubber formulation. Without intending to be bound to any specific scientific theory, it appears
that some such fillers, as noted above, and particularly those that are hydrophilic in nature (bivalent
silicates, silane-coated silica, zinc oxide, and the like), act in such a way as to draw moisture into the
article which then transports silver ions from within the article to the surface. In such a situation, then,
the rubber article may exhibit enhanced silver release resulting in higher log kill rates for certain
bacteria due to the presence of larger amounts of available surface silver ions. Other hydrophobic
fillers, such as some pigments, clays, and calcium carbonate (as some examples) appear to work in
the opposite manner by keeping water out of the target article and thus prevent silver-ion migration to
the article surface. Thus, the reduction of such silver-ion availability decreases the antibacterial
efficacy of the rubber article. In effect, then, the actual antibacterial efficacy of the entire rubber
article can be controlled through the presence of certain amounts of such generally required fillers
and oils (some hydrophilic antistatic agents also appear to act in the same manner as silica as well).
As a result, the necessary filler and/or oil constituents required to provide dimensional resiliency
and/or flexural modulus (and thus actual usefulness) of the finished article serve a dual purpose
heretofore unrecognized within the rubber industry. Rubber articles can be produced with specific
end-uses in mind depending upon the duration of antimicrobial activity desired through the addition
of specific amounts of such additives. Again, such a targeted duration antimicrobial vulcanized
article and the benefits thereof have heretofore been unknown and unrecognized within the rubber
industry. These rubber components are thus hereinafter referred to as "silver ion release control
additives".
[0014] The term EPDM rubber, as noted above, is intended to cover any standard rubber which
possesses at least a majority by weight of EPDM rubber and which must be vulcanized to provide a
dimensionally stable rubber article. It is intended that such vulcanization or other processing be
performed in an environment that is inexpensive to provide and thus should be undertaken in an
oxygen-rich atmosphere (as opposed to an anaerobic environment which is generally difficult to
provide). EPDM rubber has been utilized previously within the rubber industry for a variety of
applications and is generally well known and taught throughout the prior art. Such inventive rubber
articles should also possess a chemical plasticizer which aids in the breakdown period of the
elastomer during compounding and processing (and provides flexural modulus properties to the
finished article) as well as fillers required for reinforcement (e.g. calcium carbonate, carbon black,
silica, and clays). Optionally, to form a blown (foam or sponge) rubber type, a blowing agent may be
added to the inventive formulation.
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[0015] The non-silicone rubber component or components of the inventive rubber article is therefore
a majority of EPDM and other types of possible rubber (in order to provide different strengths,
flexibilities, or other properties) such as those, without limitation, selected from the group consisting
of nitrile rubber [such as acrylonitrile-butadiene (NBR)], styrene-butadiene rubber (SBR), natural
rubber, chloroprene, ethylene propylene rubber, natural rubber, polyurethane rubber, butyl rubbers,
isoprene, halobutyl rubbers, fluoroelastomers, epichlorohydrin rubber, polyacrylate rubber, and
chlorinated polyethylene rubber, hydrogenated SBR, hydrogenated NBR, and carboxylated NBR.
Although the presence of silicone-rubber is discouraged within the inventive formulation, there
remains the possibility of adding certain low amounts of such specific unvulcanized rubber
components without adversely affecting the overall antimicrobial rubber formulation itself. Thus, up to
25% by total weight of the formulation may be silicone-rubber; however, the vast majority of the
rubber formulation must be non-silicone rubber. Furthermore, the non-silicone rubber portion must
not possess an appreciable amount of sulfur-based curing agent or residue (in the finished article)
and thus must be vulcanized through curing with primarily non-sulfur-based compounds (such as
peroxides and metal oxides, for example). The rubber component is present in amount of from about
10 to about 1,000 parts of the entire composition, more preferably from about 50 to about 500 parts,
and most preferably from about 100 to about 200 parts. Thus, with a total number of parts between
about 300 and 2,000 parts throughout the target vulcanized rubber article, the rubber constitutes
from about 25 to about 70% of the percentage by parts of the entire article. The remainder comprises
additives such as fillers, oils, curing agents, the desired antimicrobial agents, optional blowing
agents, and the like (as discussed more thoroughly below).
[0016] Furthermore, the non-silicone rubber portion must not possess an appreciable amount of
sulfur-based curing agent or residue (in the finished article) and thus must be vulcanized through
curing with primarily non-sulfur-based compounds (such as peroxides and metal oxides, for
example). The rubber component is present in amount of from about 10 to about 1,000 parts of the
entire composition, more preferably from about 50 to about 500 parts, and most preferably from
about 100 to about 200 parts.
[0017] The antimicrobial agent of the inventive raw rubber formulation may be of any standard silverbased compounds. Such compounds, in contrast with organic types, such as triclosan, for example,
do not exhibit low thermal stability and thus remain within the target matrix or substrate at different
temperatures. Thus, such an antimicrobial is more easily controlled, as discussed above, for surface
release as desired. Such agents include, without limitation, silver salts, silver oxides, elemental silver,
and, most preferably ion exchange, glass, and/or zeolite compounds. Of even greater preference are
silver-based ion exchange compounds for this purpose due to the low levels of discoloration and
enhanced durability in the final product provided by such compounds, the efficacy provided to the
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final formulation with such a compound, and the ease of manufacture permitted with such specific
compounds. Thus, the antimicrobial agent of this invention may be any type which imparts the
desired log kill rates as previously discussed to Staphylococcus aureus, Klebsiella pneumoniae,
Escherichia coli, and Pseudomonas aeruginosa, as merely representative organisms. Furthermore,
such antimicrobial compounds must be able to withstand elevated processing temperatures for
successful incorporation within the target non-sulfur (peroxide, for example) cured EPDM rubbercontaining articles. Again, such antimicrobial agents comprise, preferably, silver-containing ion
exchange, glass, and/or zeolite compounds. Most preferably, such a compound is a silver-based
ion-exchange compound and particularly does not include any added organic bactericide
compounds (thereby not permitting a release of volatile organic compounds into the atmosphere
during processing at high temperatures, etc.). The preferred silver-based ion exchange material is
an antimicrobial silver zirconium phosphate available from Milliken & Company, under the trade
name ALPHASAN(R). Such compounds are available in different silver ion concentrations as well as
mixtures with zinc oxide. Thus, different compounds of from about 0.01 to 10% of silver ion
concentration, preferably from about 3 to about 8%, and most preferably amounts of about 3, 3.8,
and 10% by total amount of components (e.g. of the total amount of silver ions and zirconium
phosphate) are possible. Other potentially preferred silver-containing solid inorganic antimicrobials in
this invention are silver-substituted zeolite available from Sinanen under the tradename ZEOMIC(R),
or a silver-substituted glass available from Ishizuka Glass under the tradename IONPURE(R), which
may be utilized either in addition to or as a substitute for the preferred species. Other possible
compounds, again without limitation, are silver-based materials such as MICROFREE(R), available
from DuPont, as well as JMAC(R), available from Johnson Mathey.
[0018] Generally, such an antimicrobial compound is added to a rubber formulation in an amount of
from about 0.1 to 10% by total weight of the particular total rubber formulation; preferably from about
0.1 to about 5%; more preferably from about 0.1 to about 2%; and most preferably from about 0.2 to
about 2.0%.
[0019] Furthermore, with regard to silver-based inorganic antimicrobial materials, these particular
antimicrobial rubber articles are shown to be particularly suitable for the desired high levels of
efficacy and durability required of such articles. It has been found that certain silver-based ion
exchange compounds, such as ALPHASAN(R) brand antimicrobials available from Milliken &
Company, (U.S. Pat. Nos. 5,926,238, 5,441,717, 5,698,229 to Toagosei Chemical Industry Inc.),
exhibit impressive bio-efficacy. After a period of time, alternative antimicrobial compounds (e.g.
triclosan, microchek, OBPA, Zn-omadine) initially suffer from decomposition under the high
processing temperatures, followed by depletion of the biocide through leaching into the surrounding
environment and finally through depleted bactericidal activity. However, silver-containing ion
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exchange, glass, and/or zeolite compounds do not suffer from these shortcomings. Such
antimicrobial agents exhibit high temperature stability (>1000[deg.] C.), do not leach into the
environment and provide substantial amounts of the oligodynamic silver ion to provide for the desired
extensive durability.
[0020] The inventive antimicrobial articles should exhibit an acceptable log kill rate after 24 hours in
accordance with the AATCC Draft Test Method entitled "Assessment of Antimicrobial Properties on
hydrophobic Textiles and Solid Substrates" as well as in accordance with Japanese Test Method JIS
2 2801. Such an acceptable level log kill rate is tested for Staphylococcus aureus or Klebsiella
pneumoniae of at least 0.1 increase over baseline. Alternatively, an acceptable level will exist if the
log kill rate is greater than the log kill rate for non-treated (i.e., no solid inorganic antimicrobial added)
rubber articles (such as about 0.5 log kill rate increase over control, antimicrobial-free vulcanized
EPDM rubber). Preferably these log kill rate baseline increases are at least 0.3 and 0.3, respectively
for S. aureus and K. pneumoniae; more preferably these log kill rates are 0.5 and 0.5, respectively;
and most preferably these are 1.0 and 1.0, respectively. Of course, the high end of such log kill rates
are much higher than the baseline, on the magnitude of 5.0 (99.999% kill rate). Any rate in between is
thus, of course, acceptable as well. However, log kill rates which are negative in number are also
acceptable for this invention as long as such measurements are better than that recorded for
correlated non-treated rubber articles. In such an instance, the antimicrobial material present within
the rubber article at least exhibits a hindrance to microbe growth. Furthermore, such rubber articles
should exhibit log kill rates of the same degree for other types of bacteria, such as, Psedumonas
aeruginosa and Eschericia coli.
[0021] Such antimicrobial activity is noticed only in relation to a sufficient amount of surface available
silver ions on the target rubber article. A high number per surface area (such as above about 0.075
ppb/cm) is thus required for acceptable antimicrobial efficacy. Such a measurement is basically
taken through the immersion of individual samples of colored rubber articles within 15 mL buffer
solutions at elevated temperatures for an hour. This extraction test is described in greater detail
below with a sodium-potassium phosphate salt solution.
[0022] Of great surprise within this invention is the ability for the finished inventive articles to provide
antifungal benefits as well as antibacterial characteristics. Such versatility is rare among antibacterial
compounds; however, without intending to be limited to any particular scientific theory, it appears
that the silver ions, and particularly the silver ions present at the article surface in great abundance,
provide excellent antifungal properties. In order to provide a greater array of potential antifungal
benefits, other compounds may be incorporated within the target pre-vulcanized rubber formulation
(and subsequent article), such as the aforementioned potential filler component zinc oxide, as one
example.
261/425
[0023] Of great importance to the effectiveness of the inventive articles in terms of antimicrobial and
antifungal activity is the omission of deleterious amounts of sulfur-based curing agents and
accelerators from the rubber article. As noted above, it is believed, without intending to be bound to
any specific scientific theory, that sulfur reacts with the preferred silver-based antimicrobials and
irreversibly binds the silver ions (as silver sulfides, for example) within the rubber composition and/or
article itself. As such, the resultant silver sulfides, etc., are ineffective as antimicrobial agents and
their presence thus renders the final product antimicrobially inactive. Thus, it has been necessary to
produce a vulcanized rubber article lacking any appreciable amount of sulfur curing agents and
accelerators therein. It should be appreciated that the term "appreciable amount" permits a small
amount to be present. It has been found that, as a molar ratio, a 1:1 ratio (and above) between sulfur
molar presence and silver molar presence results in a clear loss of antimicrobial activity within the
desired ultimate vulcanized article. However, greater molar amounts of silver in relation to sulfur
provide at least some antimicrobial properties to the desired article. A molar ratio range of from
0.25:1 to about 0.000000001:1 of sulfur to silver ions is thus at least acceptable. The primary curing
agent, however, must be of non-sulfur nature (and is preferably, though not necessarily) a peroxidebased compound in order to provide the desired antimicrobial activity for the subject
[0024] Surprisingly, it has now been found that the inventive rubber articles listed above are available
without such sulfur-based curing agents in any appreciable amounts; most importantly, with the
introduction of certain additives, the structural integrity and/or flexural modulus of the rubber
formulation is improved to an acceptable level and the efficacy of the antimicrobial components are
can be controlled simultaneously.
[0025] Thus, the curing agent present within the raw rubber formulation to be vulcanized to form the
inventive article must be at least a majority, and preferably at least about 75% by weight of a nonsulfur-based curing agent. As discussed above, traditional sulfur and sulfur-based catalysts will not
work with the inventive antimicrobial formulations due to chemical reactions between the sulfur atoms
and and the biocidal Ag+ ion. However, non-sulfur-based catalysts, such as, for example, and
without intending to being limited to peroxides, certain compounds provide effective curing for the
inventive raw rubber formulations, such as organic peroxides, including dicumyl peroxide, 2,5-bis(tbutylperoxy)-2,5-dimethylhexane, di-(t-butyl-peroxy-isopropyl) benzene, di-(t-butyl-peroxy-trimethyl)cyclohexane, and the like, and inorganic peroxides and oxides, including zinc oxide, and the like.
Such a curing agent should be present in amount of from about 0.5 to about 100 parts per hundred
parts of rubber (pphr); more preferably from about 1 to about 50 pphr; and most preferably from
about 2 to about 10 pphr, all either as one curing agent alone, or as the combination of any number
of different types.
262/425
[0026] Other additives present within the inventive vulcanized rubber article include any of the
aforementioned silver ion release control additives, accelerators, accelerator activators,
antidegradants, softeners, abrasives, colorants, flame retardants, homogenizing agents, internal
lubricants, and deodorants. Such components should be present, if at all, in rather low amounts, of
from about 0.1 to about 10 pphr.
[0027] It has further been unexpectedly determined that a substantial increase in the antibacterial
and antifungal efficacy is provided upon washing the finished inventive article. Abrading the surface
of such an article also permits increases in such characteristics due to an increase in Ag+ release;
however, industrial laundering of certain rubber products (mats, and the like) can be improved in
antimicrobial, etc., efficacy through a simple washing. In fact, such an increase steadily improves
with greater numbers of consistent washes such that it has been found that a rubber article as first
vulcanized exhibits lower overall antibacterial and antifungal activity than one that has been washed
one, two, three, and up to at least 20 times (in a standard industrial rotary washing machine). Such a
surprising benefit thus permits utilization of such rubber articles as floor coverings (mats, as one
example, such as those with carpeted portions or those which are rubber alone; particularly foamed
rubber mats for antifatigue properties and reduced specific gravity so as to reduce the chances of
machinery damage during such industrial rotary launderings and dryings), and other articles which
can be easily washed within standard laundry machines.
[0028] Furthermore, as alluded to above, friction with the subject rubber article surface can remove
very slight layers of rubber from the article surface thereby permitting "fresh" silver-comprising
crystallites to the surface to act as desired in their antibacterial and/or antifungal capacities. Basically,
then, the inventive article produced from the inventive raw rubber formulation exhibits an even
dispersion of antimicrobial particles throughout the entire rubber article. Such an even dispersion of
the biocide throughout the rubber article thus provides a reservoir of fresh crystallites containing the
biocidal metallic ion. As layers of the rubber are worn and abraded away, antimicrobial particles
containing untapped silver ions become available.
[0029] The preferred peroxide-cured colored EPDM and/or NBR rubber-containing articles of this
invention containing the antimicrobial agent can be processed into rubber articles which exhibit
excellent antimicrobial qualities as well as antimicrobial efficiency throughout the rubber article's
lifetime. Examples of other such colored rubber articles encompassed within this invention include,
but are not limited to hard rubber mats, sponge or foam rubber mats, static dissipative rubber mats,
anti-fatigue rubber mats, rubber mats which include a face fiber, rubber link mats, rubber gaskets,
rubber medical goods, rubber gloves, rubber medical devices, rubber conveyor belts, rubber belts
and rubber wheels used in food processing, rubber clothing, rubber shoes, rubber boots, rubber
tubing, rubber seals, rubber plungers, rubber vehicle bumpers, rubber shoe soles, rubber
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components for containers, and rubber automotive fuel hoses. Such inventive formulations may also
be incorporated into a multilayered rubber article in which the antimicrobial agent can be
incorporated into any surface layer and still provide the desired antimicrobial efficiency.
[0030] Of particular interest is the formation of multilayered rubber articles wherein at least one of
such rubber layer exhibits the desired antimicrobial activity and thus is made from an inventive
EPDM rubber-containing article. Such layered articles may be adhered together through covulcanization, gluing, and the like. Furthermore, layers of other types of materials may be placed
being rubber layers as well to provide, as one non-limiting property, better structural stability to the
desired multilayered article. Furthermore, such articles may have at least antimicrobial layer colored
and at least one antimicrobial layer uncolored (black or white); or at least one antimicrobial layer
colored and at least one uncolored layer (non-antimicrobial); or at least one colored antimicrobial
layer, and any others either antimicrobial or not. Basically, any arrangement of such multilayered
articles will suffice for this invention as long as at least one layer is an inventive colored antimicrobial
rubber formulation as defined herein. Of course, such an inventive rubber formulation may also be a
layer (or layers) or component (such as a seal) within any other type of article (such as a metal article,
or between two metal articles, a plastic article, or between two or more plastic articles, and the like).
[0031] The non-limiting preferred embodiments of these rubber formulations and articles are
discussed in greater detail below.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Inventive Raw Rubber Formulations
[0033] Initially, raw rubber formulations without coloring agents were produced and vulcanized to
analyze the effects of the silver-containing antimicrobial (in this situation a silver ion-exchange
zirconium phosphate salts available from Milliken & Company under the tradename ALPHASAN(R)
conforming to the general formula of comprising about 10.0% by weight of silver ion concentration
within the ion-exchange compound of AgxNayHzZr2(PO4)3, where x+y+z=1. The formulations and
color determinations are as follows:
(Inventive) EPDM Base Formulation 1
[0034]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP100parts
from DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
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Zinc Oxide50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%by weight
(Inventive) EPDM Base Formulation 2
[0035]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
Calcium carbonate50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Inventive) EPDM Base Formulation 3
[0036]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
Calcined Clay50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
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(Inventive) EPDM Base Formulation 4
[0037]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
China Clay50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Inventive) EPDM Base Formulation 5
[0038]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
Magnesium Silicate50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Inventive) EPDM Base Formulation 6
[0039]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
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Silica/Silane Oil Combination (Aktisil (R) MAM, from50pphr
Hoffman Minerals)
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Inventive) EPDM Base Formulation 7
[0040]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
Aluminum trihydrate50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Inventive) NBR Base Formulation 8
[0041]
ComponentAmount
Acrylonitrile butadiene Rubber (from Zeon Chemicals)100parts
Stearic acid1pphr
Microcrystalline wax2pphr
Polyethylene glycol5pphr
Zinc oxide5pphr
Calcium carbonate20pphr
di-octyl-phthalate3pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
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Antimicrobial1.5%
(Comparative) EPDM Base Formulation 1
[0042]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
Silica50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Comparative) EPDM Base Formulation 2
[0043]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
Pentaerythritol tetrastearate (processing aid)2pphr
Aluminum silicate50pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Comparative) EPDM Base Formulation 3
[0044]
ComponentAmount
Ethylene-propylene diene modified Rubber (Nordel IP from100parts
DuPont-Dow)
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Pentaerythritol tetrastearate (processing aid)2pphr
Stearic acid0.5pphr
Paraffinic oil50pphr
Ethyleneglycol dimethacrylate2.5pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
(Comparative) NBR Base Formulation 4
[0045]
ComponentAmount
Acrylonitrile butadiene Rubber (from Zeon Chemicals)100parts
Stearic acid1pphr
Microcrystalline wax2pphr
Polyethylene glycol5pphr
Silica40pphr
Zinc oxide5pphr
Calcium carbonate20pphr
di-octyl-phthalate3pphr
di-(tert-butyl-peroxy-isopropyl)benzene4pphr
di-(tert-butyl-peroxy-trimethyl)-cyclohexane4pphr
Antimicrobial1.5%
[0046] The compounding of ingredients within each formulation can be carried out in an open mill, an
internal mixer, or an extruder where intensive mixing within the polymer matrix of each component
will take place. During the mixing operation, the control of temperature rise, due to high shear
incorporation of the ingredients, is crucial to ensure that pre-vulcanization (scorch) does not take
place during processing. Generally, a maximum temperature of 120[deg.] C. is reached on single
stage (pass) mixing through an internal mixer. The compounds can be further processed after mixing
into specific forms to allow adequate presentation for manufacturing into products. This could be
calendering, extrusion, granulation/pelletization, strip form, fabrication and preforming into specific
shaped blanks of 3 inches*2 inches in size through compression molding for 10 minutes at 180[deg.]
C. and subsequent cooling to room temperature.
[0047] The vulcanization of the compounds can be in the form of molding (compression, transfer,
injection), continuous extrusion (LCM, UHF[where permissible], autoclave and hot air), and coatings.
The vulcanization (cure) temperatures can range from 150[deg.] C. to 250[deg.] C. In this specific
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situation, the rubber articles were calendared into rough mat structures and then subjected to
vulcanization under high temperature and pressure.
[0048] Rubber itself does not exhibit dark colorations unless specific pigments (e.g., carbon black,
for example) are added, or unless other sources of colorations (dark or otherwise) are present. The
finished vulcanized structures thus should not exhibit any appreciable colorations except for
discolorations present due to filler-silver ion complexation. Low discolorations are thus acceptable for
the inclusion of other color sources to impart desired colorations to vulcanized rubber formulations
further comprising a coloring agent during vulcanization. High discolorations within such uncolored
base vulcanized formulations will not permit such coloring due to dominance of the dark
discolorations produced through the unwanted silver ion-filler complexation (or like reaction). Thus,
the above uncolored vulcanized samples were analyzed empirically for acceptable low discoloration
levels. In the table below, a +++ indicates extremely low colorations, a ++ indicates very low
discolorations, a + indicates at least acceptable low discolorations (all for coloring of intended
finished vulcanized rubber articles), and a - or -- indicates unacceptable high discolorations. The
results were as follows:
DISCOLORATION RESULTS TABLE
Base EPDM FormulationAppearance
(Inventive) 1+ + +
(Inventive) 2+ +
(Inventive) 3+ +
(Inventive) 4+ +
(Inventive) 5+ +
(Inventive) 6+ +
(Inventive) 7+
(Inventive) 8+ +
(Comparative) 1- (Comparative) 2- (Comparative) 3+ + +
(Comparative) 4- [0049] Of course, the third comparative example was the control rubber without any filler component.
Although it exhibited excellent low discoloration, the lack of a proper filler resulted in low dimensional
stability for the overall product, and thus it was unacceptable for further use.
[0050] Thus, selected formulations of the acceptable low discoloration base rubbers were then
prepared with certain colorants added thereto to provide the desired coloring effects. Thus, 5 php of
titanium dioxide (for white), 5 php of a phthalocyanine blue (RD Blue B609 from Prima Colour), 5 php
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of a di-arylide yellow (RD Yellow B581 from Prisma Colour), and 5 php of a phthalocyanine green (RD
Green B592 from Prisma Colour), were all individually mixed within inventive EPDM base formulation
2, above, to produce the desired antimicrobial colored EPDM rubber articles (calendared sheets).
[0051] Analyses for Surface-Available Silver
[0052] Each such colored article (small samples of about ?? dimensions) was then exposed to an
extract solution at room temperature for 24 hours (or more, as listed below). In each instance below,
the extract solution used was a sodium-potassium phosphate buffer solution, although any salt
solution (e.g., sodium chloride, calcium chloride, and the like) could also be utilized as the test
extract solution as long as proper silver extraction is permitted with such solutions. Controls with
silver antimicrobial but no carboxylic acid salt were tested as comparisons.
[0053] The extraction procedure and analyses involved first producing a standard plot of different
silver concentrations within a nitric acid solution. The silver preparations were prepared by first
weighing out 1000 ppm of silver into 100 mL volumetric flask and adding a sufficient amount of a 5%
nitric acid solution to the flask to the fill line (to produce a 1 ppm silver standard). A further dilution of
10 g of the 1 ppm preparation into a 100 mL volumetric flask and then adding the remainder of 5%
nitric acid solution (to produce a 100 ppb standard. A final 500 ppb standard was then prepared in
similar fashion with 5 g of the 100 ppb standard used. The concentrations were then measured by
utilization of inductively coupled plasma spectroscopy for such silver content. The results were then
plotted for comparison with the eventual silver content of the extract solutions below.
[0054] The extract solution a 1X strength solution of a sodium-potassium-phosphate solution (initially
about 145 g of sodium phosphate mixed with about 71 g of potassium phosphate diluted in a 1 liter
volumetric flask with deionized water, with a subsequent dilution of 100 mL of this first solution to
1000 mL with deionized water). The treated plaques were then individually placed within a sealed
plastic bag with a sufficient amount of the extract solution to fully immerse the sample. The bag was
then placed and placed on an orbital shaker at 140 rpm and kept at room temperature for 24 hours.
After that time, 9.5 mL of the resultant extract solution was then placed into a 15 mL vial with 0.5% of
70% nitric acid added. The resultant test extract solution was then subjected to ICP spectroscopy
and the resulting measurements of silver concentration were then plotted against the standards,
above. The measurements for the above plaque samples are as follows:
EXPERIMENTAL SILVER EXTRACTION TABLE
Example #Amount of Silver Detected ([mu]g/dm)
White0.344
Blue0.106
Yellow0.094
Green0.142
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[0055] Thus, since a target of 0.075 [mu]g/dmis necessary to theoretically impart the desired
antimicrobial activity to the target rubber article, these examples clearly provided sufficient surface
available silver while still retaining effective and pleasing colorations therein.
[0056] Having described the invention in detail it is obvious that one skilled in the art will be able to
make variations and modifications thereto without departing from the scope of the present invention.
Accordingly, the scope of the present invention should be determined only by the claims appended
hereto.Claims:
1. A dimensionally stable colored vulcanized rubber article comprising at least one silver-based
antimicrobial agent, wherein said colored rubber article exhibits a minimum of 0.075 [mu]g/dmof
surface available silver.
2. The rubber article of claim 1 wherein said silver-based antimicrobial compound is selected from
the group consisting of elemental silver, silver oxides, silver salts, silver ion exchange compounds,
silver zeolites, silver glasses, and any mixtures thereof.
3. The rubber article of claim 1 wherein said article further comprises at least one silver ion control
release additive.
4. The rubber article of claim 2 wherein said article further comprises at least one silver ion control
release additive.
5. The rubber article of claim 3 wherein said at least one silver ion control release additive is selected
from the group consisting of fillers, oils, and mixtures thereof.
6. The rubber article of claim 5 wherein said at least one silver ion control release additive is a
hydrophilic filler selected from the group consisting of metal silicates, metal stearates, metal oxides,
metal carbonates, clays, silica treated with silane oil, and any mixtures thereof.
7. The rubber article of claim 4 wherein said at least one silver ion control release additive is selected
from the group consisting of fillers, oils, and mixtures thereof.
8. The rubber article of claim 7 wherein said at least one silver ion control release additive is a
hydrophilic filler selected from the group consisting of metal silicates, metal stearates, metal oxides,
metal carbonates, clays, silica treated with silane oil, and any mixtures thereof.
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9. The rubber article of claim 1 wherein said rubber constituent is selected from the group consisting
of EPDM, NBR, and any mixtures thereof.
10. A method of producing a colored rubber article exhibiting a minimum surface availability of silver
ions of 0.075 [mu]g/dm, comprising the steps of
a) compounding together an unvulcanized rubber formulation comprising at least one rubber
constituent, the majority of which must be a non-silicone rubber, at least one silver-based
antimicrobial compound, at least coloring agent, at least one filler component, and at least one
curing compound, wherein no black coloring agents are present, and wherein said curing compound
present within said formulation does not include an appreciable amount of sulfur-based compounds,
b) molding said rubber formulation into a preselected shape, and
c) vulcanizing said rubber formulation under high pressure and exposure to high temperature.
11. The method of claim 10 wherein said silver-based antimicrobial compound is selected from the
group consisting of elemental silver, silver oxides, silver salts, silver ion exchange compounds, silver
zeolites, silver glasses, and any mixtures thereof.
12. The method of claim 11 wherein said at least one filler component simultaneously functions as a
silver ion control release additive.
13. The method of claim 12 wherein said at least one filler/silver ion control release additive is
selected from the group consisting of fillers, oils, and mixtures thereof.
14. The method of claim 13 wherein said at least one filler/silver ion control release additive is a
hydrophilic filler selected from the group consisting of metal silicates, metal stearates, metal oxides,
metal carbonates, clays, silica treated with silane oil, and any mixtures thereof.
15. The rubber article of claim 10 wherein said rubber constituent is selected from the group
consisting of EPDM, NBR, and any mixtures thereof.
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32. WO03055659 - 10.07.2003
METHOD FOR MOULDING UNDER PRESSURE NON-VULCANIZED RUBBER MATERIAL
PARTICLES
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO03055659
Inventor(s):
CALVAR DIDIER [FR] (--); GRIFFON MICHEL [FR] (--); LABAUZE GERARD [FR] (--)
Applicant(s): MICHELIN SOC TECH [FR] (--); MICHELIN RECH TECH [CH] (--); CALVAR DIDIER
[FR] (--); GRIFFON MICHEL [FR] (--); LABAUZE GERARD [FR] (--)
IP Class 4 Digits: B29C; B29B; B29D
IP Class:
B29B15/02; B29C43/00; B29D29/08; B29B9/00; B29C43/22
E Class: B29B13/10; B29C43/00B
Application Number:
WO2002EP14539 (20021219)
Priority Number: FR20010016971 (20011226); FR20010016967 (20011226)
Family: WO03055659
Equivalent:
AU2002367095
Cited Document(s):
US3381072; FR1419312; FR1597887; EP0002195; US3526688;
DE4212765; US4207218; US5075057; US2620320; US6177042
Abstract:
THE INVENTION CONCERNS A METHOD FOR SHAPING SEMI-FINISHED PRODUCTS FROM A
MIXTURE BASED ON SULPHUR-VULCANIZABLE DIENE ELASTOMERS COMPRISING A FIT STEP
WHICH CONSISTS IN DISSOCIATING SAID NON-VULCANIZED MIXTURE TO OBTAIN SMALL
SINGLE-UNIT ELEMENTS, A SECOND STEP WHICH CONSISTS IN DISTRIBUTING SAID ELEMENTS
IN A MOULD, A THIRD STEP WHICH CONSISTS IN COMPRESSING SAID ELEMENTS IN A MOULD
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AND A FOURTH STEP WHICH CONSISTS IN STRIPPING THE RESULTING NON-VULCANIZED
SEMI-FINISHED PRODUCT.Description:
PROCEDE DE MOULAGE SOUS PRESSION DE PARTICULES EN MATIERE CAOUTCHOUTEUX
NON VULCANISES
L'invention concerne un procйdй de mise en forme de semi-finis non vulcanisйs constituйs d'un ou
plusieurs mйlanges caoutchouteux, c'est-а-dire de mйlanges а base d'йlastomиres diйniques, et
pour lesquels, compte tenu soit de leur forme gйnйralement volumineuse ou soit de la nature du
mйlange utilisй, les techniques classiques sont inopйrantes.
Les techniques d'extrusion de mйlanges caoutchouteux sont aujourd'hui bien connues et
maоtrisйes par l'homme de l'art.
Cependant il s'avиre parfois nйcessaire de rйaliser des semi-finis en forme de plot ou de barrette
d'une taille pouvant varier de 0,5 а 2 dm3, et dont la fabrication ne peut pas tre directement
rйalisйe par extrusion. Cette technique gйnиre en effet des profilйs d'йpaisseur limitйe, qu'il est
nйcessaire de modeler par des opйrations de coupe d'autant plus complexes qu'elles sont souvent
multidirectionnelles et s'opиrent sur des йpaisseurs de produit importantes. La maоtrise du poids et
du profil extйrieur des objets reprйsente alors une difficultй supplйmentaire. De mme, dans le
cadre de l'amйlioration constante de la performance des pneumatiques, notamment dans le
domaine de l'adhйrence, il est parfois avantageux de pouvoir mettre en forme des matйriaux qui а
cru sont trиs йlastiques et manquent de cohйsion, afin de rйaliser par exemple des bandes
profilйes. Ces deux caractйristiques pйnalisent fortement l'extrusion de ces mйlanges voire mme
rendent certains mйlanges non extrudables.
Les techniques de mise en forme par compression, йgalement bien connues, qui consistent а partir
d'une masse de matiиre mise dans un moule а appliquer une trиs forte pression et tempйrature
afin que la masse adopte la forme du moule permettent de rйaliser des semi-finis de cette taille mais
sont limitйes en ce sens
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qu'il n'est pas possible de maоtriser la stabilitй dimensionnelle dans toutes les directions du produit
semi-fini aprиs le dйmoulage. En effet, pour les mйlanges de forte йlasticitй, les contraintes
internes imposйes au mйlange pendant l'opйration de compression, se libиrent, engendrant le
phйnomиne bien connu de foisonnement et de dйformation du semi-fini rйalisй.
Le problиme est identique pour les techniques d'injection.
De maniиre gйnйrale, toutes ces techniques reposent sur des transferts, donc des mouvements de
matйriaux plus ou moins importants. Et il est bien connu de l'homme de l'art que les mйlanges
caoutchouteux conservent la mйmoire des contraintes qu'ils accumulent pendant ces mouvements
et ont tendance а libйrer ces contraintes une fois revenus а l'йtat libre, entraоnant une йvolution
alйatoire de la gйomйtrie de l'objet rйalisй. C'est ce que l'on dйcrit couramment sous le
phйnomиne de foisonnement.
Il existe bien une solution qui consiste а ajouter des fibres а l'intйrieur du mйlange. Ces fibres,
telles que par exemple des fibres textiles aramides d'environ 6mm de longueur, permettent de
contenir l'expression de ces contraintes internes et de maоtriser la stabilitй dimensionnelle du semifini aprиs dйmoulage.
Cependant l'opйration d'injection avec des fibres reste trиs dйlicate et rend plus complexe le
procйdй et bien entendu, elle nйcessite une vйrification des propriйtйs des matйriaux ainsi
obtenus pour que ces derniиres ne soient pas dйtйriorйes.
On peut йgalement maintenir le produit en compression pendant plusieurs heures avant de
procйder а son dйmoulage, mais lа encore le procйdй а mettre en oeuvre reste limitй dans ses
applications industrielles.
L'invention vise а pallier ces inconvйnients.
La demanderesse a dйcouvert qu'il йtait possible d'agglomйrer par compression des йlйments de
mйlanges non vulcanisйs de petite taille pour obtenir des semi-
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finis d'une rigiditй suffisante et d'une bonne stabilitй dimensionnelle sans qu'il soit nйcessaire
d'ajouter des fibres ou d'autres matйriaux pour obtenir ces propriйtйs.
En effet il a йtй observй qu'il suffisait de rйduire les dйplacements de matiиre et de maоtriser la
direction et la valeur du foisonnement pour se libйrer des inconvйnients dйcrits prйcйdemment.
Le procйdй consiste а rйaliser des йlйments unitaires de mйlange non vulcanisй de faible
dimension et dont la taille aura йtй judicieusement choisie. Aprиs avoir si nйcessaire prйchauffй
ces йlйments unitaires а une tempйrature infйrieure а la tempйrature de vulcanisation, on dispose
une masse prйdйterminйe de ces йlйments unitaires dans un moule ouvert et ayant
approximativement la forme du semi-fini а rйaliser, en remplissant tout ou partie du volume de faзon
contrфlйe.
On s'assure ainsi que chacun des йlйments unitaires ne subira qu'une contrainte globalement
unidirectionnelle et homogиne au moment de la mise en compression. La pression de mise en forme
est ajustйe pour permettre l'йvacuation de l'air occlus et pour assurer la cohйsion finale des
йlйments unitaires.
Lorsque la forme du moule le permet, la mise en compression peut tre assurйe par la face mobile
d'un piston, venant fermer le moule, et que l'on maintient а une position prйdйterminйe. Mais il est
йgalement possible de venir injecter, par des techniques classiques, un faible volume
complйmentaire de mйlange de mme nature ou de nature diffйrente du mйlange prйcйdent, de
maniиre а assurer le remplissage complet de la cavitй а la pression dйsirйe.
Il suffit alors, de dйmouler le semi-fini ainsi rйalisй, et si cela s'avиre nйcessaire, de le maintenir
bloquй en extension dans la direction proche de celle dans laquelle s'est exercй le dйplacement
du piston ou de celle du sens d'йcoulement des buses d'injection, en l'insйrant pendant un temps
dйterminй dans des
cassettes prйvues а cet effet pour en assurer la stabilisation.
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Il est possible а cet йgard de faire une analogie avec le procйdй de mise en forme de poudres
mйtalliques et de cйramiques couramment appelй le frittage ainsi transposй а la mise en forme
de mйlanges caoutchouteux.
Selon l'invention, le procйdй de mise en forme de produits semi-finis а partir d'un mйlange а base
d'йlastomиres diйniques vulcanisable au soufre consistant а : - dissocier ledit mйlange pour
obtenir de petits йlйments unitaires, - peser une masse prйdйterminйe de petits йlйments
unitaires, а les rйchauffer si nйcessaire, puis а rйpartir lesdits йlйments dans un moule, comprimer lesdits йlйments, - dйmouler le semi-fini non vulcanisй ainsi rйalisй et, si cela s'avиre
nйcessaire, le maintenir dans des cassettes de maniиre а en assurer la stabilisation.
D'autres caractйristiques et avantages de l'invention apparaоtront а la lecture de la description du
procйdй et d'exemples de rйalisation par la mise en oeuvre du procйdй conforme а l'invention.
L'exemple 1 concerne la rйalisation de chenilles destinйes а des engins de gйnie civil ou а des
tracteurs agricoles. La fabrication de ces produits comprend gйnйralement une ou plusieurs
йtapes d'assemblage de produits crus suivies d'une йtape de cuisson. Pour rйaliser cet
assemblage, on fait appel au moins partiellement а des produits semi-finis non vulcanisйs
constituйs par des plots qui forment les dents d'engrenage des chenilles, et des barrettes qui
forment une partie de la bande de roulement. Ces deux semi-finis non vulcanisйs sont rйalisйs par
la mise en oeuvre du procйdй objet de l'invention puis sont assemblйs sur un procйdй non dйcrit
dans le prйsent document, avec le corps de la chenille rйalisй а
base de mйlanges caoutchouteux d'йpaisseur, de longueur, de largeur variables et qui possиdent
un profil dйfini. La mise en forme des produits caoutchouteux du corps de la chenille est rйalisйe
principalement par extrusion.
L'exemple 2 concerne la rйalisation d'une bande profilйe continue, formйe par la juxtaposition de
portions longitudinales rйalisйes par la mise en oeuvre du procйdй objet de l'invention. Il est ainsi
possible de confectionner une bande de roulement en utilisant un mйlange difficilement extrudable
par une technique classique. Aprиs mise а longueur, ce semi-fini est ensuite assemblй de maniиre
connue et non dйcrite dans le prйsent document sur un tambour de confection ou de finition avec
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les autres constituants du pneumatique, avant l'йtape de vulcanisation dans un moule oщ il
adoptera sa forme dйfinitive.
L'invention est dйcrite dans la suite en rйfйrence aux dessins dans lesquels : - la figure 1 est une
reprйsentation schйmatique d'un mode de rйalisation des miettes.
- La figure 2 est une reprйsentation schйmatique d'un mode de rйalisation des miettes par
extrusion de petits profilйs.
- La figure 3 est une reprйsentation perspective schйmatique d'une chenille dont les plots ou
barrettes sont rйalisйes selon le procйdй conforme а l'invention, - La figure 4 est une
reprйsentation schйmatique d'un mode de rйalisation d'un plot de chenille par injection d'un
volume complйmentaire par extrusion.
- La figure 5 est une reprйsentation schйmatique d'un mode de rйalisation d'un plot de chenille par
piston.
- La figure 6 est une reprйsentation schйmatique d'une cassette de stabilisation.
- La figure 7 est une reprйsentation longitudinale schйmatique d'un mode de rйalisation de bandes
profilйes.
- Les figures 8 а 13 sont des modes de reprйsentation transversales schйmatiques du cycle de
rйalisation des bandes profilйes.
Par mйlange, йlastomиre ou caoutchouc"diйnique", on entend de maniиre connue un йlastomиre
issu au moins en partie (i. e. un homopolymиre ou un copolymиre) de monomиres diиnes
(monomиres porteurs de deux doubles liaisons carbone- carbone, conjuguйes ou non).
Le procйdй de fabrication de produits semi-finis part d'un mйlange caoutchouteux. La composition
du mйlange prйsente des йlastomиres diйniques ainsi que les additifs gйnйralement utilisйs
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dans les compositions caoutchouteuses destinйes а la fabrication de pneumatique а savoir du
soufre, du zinc et autres constituants classiques connus de l'homme du mйtier.
De maniиre gйnйrale, on entend ici par йlastomиre diйnique"essentiellement insaturй"un
йlastomиre diйnique issu au moins en partie de monomиres diиnes conjuguйs, ayant un taux de
motifs ou unitйs d'origine diйnique (diиnes conjuguйs) qui est supйrieur а 15% (% en moles).
C'est ainsi, par exemple, que des йlastomиres diйniques tels que les caoutchoucs butyle ou les
copolymиres de diиnes et d'alpha-olйfines type EPDM (terpolymиre йthylиne-propylиne-diиne)
n'entrent pas dans la dйfinition prйcйdente et peuvent tre notamment qualifiйs d'йlastomиres
diйniques"essentiellement saturйs" (taux de motifs d'origine diйnique faible ou trиs faible, toujours
infйrieur а 15%).
Dans la catйgorie des йlastomиres diйniques"essentiellement insaturйs", on entend en particulier
par йlastomиre diйnique"fortement insaturй"un йlastomиre diйnique ayant un taux de motifs
d'origine diйnique (diиnes conjuguйs) qui est supйrieur а 50%.
Ces dйfinitions йtant donnйes, on entend en particulier par йlastomиre diйnique essentiellement
insaturй susceptible d'tre mis en oeuvre dans les compositions conformes а l'invention : - tout
homopolymиre obtenu par polymйrisation d'un monomиre diиne conjuguй ayant de 4 а 12
atomes de carbone ; - tout copolymиre obtenu par copolymйrisation d'un ou plusieurs diиnes
conjuguйs entre eux ou avec un ou plusieurs composйs vinyle aromatique ayant de 8 а 20 atomes
de carbone ; A titre de diиnes conjuguйs conviennent notamment le butadiиne-1,3, le 2- mйthyl-1,
3-butadiиne, les 2,3-di (alkyle en C1 а C5)-1, 3-butadiиnes tels que par exemple le 2, 3-dimйthyl-1,
3-butadiиne, le 2, 3-diйthyl-1, 3-butadiиne, le 2-mйthyl- 3-йthyl-1, 3-butadiиne, le 2-mйthyl-3isopropyl-1, 3-butadiиne, un aryl-1, 3- butadiиne, le 1,3-pentadiиne, le 2, 4-hexadiиne.
A titre de composйs vinyle-aromatiques conviennent par exemple le styrиne, l'ortho-, mйta-, paramйthylstyrиne, le mйlange commercial"vinyle-toluиne", le para-tertiobutylstyrиne, les
mйthoxystyrиnes, les chlorostyrиnes, le vinylmйsitylиne, le divinylbenzиne, le vinylnaphtalиne.
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Les copolymиres peuvent contenir entre 99% et 20% en poids d'unitйs diйniques et entre 1% et
80% en poids d'unitйs vinyle-aromatiques. Les йlastomиres peuvent avoir toute microstructure qui
est fonction des conditions de polymйrisation utilisйes, notamment de la prйsence ou non d'un
agent modifiant et/ou randomisant et des quantitйs d'agent modifiant et/ou randomisant employйes.
Les йlastomиres peuvent tre par exemple а blocs, statistiques, sйquencйs, microsйquencйs, et
tre prйparйs en dispersion ou en solution ; ils peuvent tre couplйs et/ou йtoilйs ou encore
fonctionnalisйs avec un agent de couplage et/ou d'йtoilage ou de fonctionnalisation.
De maniиre particuliиrement prйfйrentielle, l'йlastomиre diйnique de la
composition conforme а l'invention est choisi dans le groupe des йlastomиres diйniques fortement
insaturйs constituй par les polybutadiиnes (BR), les polyisoprиnes (IR) ou du caoutchouc naturel
(NR), les copolymиres de butadiиne-styrиne (SBR), les copolymиres de butadiиne-isoprиne (BIR),
les copolymиres d'isoprиne-styrиne (SIR), les copolymиres de butadiиne-acrylonitrile (NBR), les
copolymиres d'isoprиne-styrиne (SIR), les copolymиres de butadiиne- styrиne-isoprиne (SBIR),
les copolymиres de butadiиne-styrиne-acrylonitrile (NSBR) ou un mйlange de deux ou plus de ces
composйs.
Nйanmoins de tels polymиres diйniques peuvent tre utilisйs seuls ou en coupage avec d'autres
йlastomиres conventionnellement utilisйs dans les pneumatiques tels que des йlastomиres
diйniques constituйs par : - un copolymиre ternaire obtenu par copolymйrisation d'йthylиne,
d'une a-olйfine ayant 3 а 6 atomes de carbone avec un monomиre diиne non conjuguй ayant de 6
а 12 atomes de carbone, comme par exemple les йlastomиres obtenus а partir d'йthylиne, de
propylиne avec un monomиre diиne non conjuguй du type prйcitй tel que notamment
l'hexadiиne-1, 4, l'йthylidиne norbornиne, le dicyclopentadiиne ; - un copolymиre d'isobutиne et
d'isoprиne (caoutchouc butyle ou IIR), ainsi que les versions halogйnйes, en particulier chlorйes
ou bromйes (BIIR), de ce type de copolymиre, - ou un copolymиre d'isobutиne et de
paramйthylstyrиne, ainsi que les versions halogйnйes, en particulier chlorйes ou bromйes (BIMS),
de ce type de copolymиre.
Le premier exemple concerne la fabrication de plot ou de barrettes destinйs а la rйalisation de
chenilles de tracteur agricole.
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La figure 3 reprйsente une chenille 31 pour vйhicule agricole ou de gйnie civil, comportant des
plots 32 sur sa surface intйrieure permettant l'entraоnement de la
chenille en coopйrant avec des dents non reprйsentйes et comportant des barrettes 33 sur sa
surface extйrieure de contact avec le sol.
A partir d'un mйlange caoutchouteux crus vulcanisable au soufre, qui peut se prйsenter sous forme
de plaques ou de bandes continues empilйes, on rйalise dans une dissociation dudit mйlange afin
d'obtenir des miettes ou des granulйs G.
Cette opйration peut tre effectuйe sur une broyeuse, illustrйe schйmatiquement sur la figure 1,
pour l'obtention de miettes telle qu'une broyeuse du commerce utilisйe gйnйralement pour les
plastiques, par exemple, la broyeuse commercialisйe par la sociйtй PREVIERO sous la
dйnomination commerciale MU305N. On peut de cette maniиre obtenir des granulйs d'une taille
infйrieure а 1 Omm et, pour avoir une plus grande prйcision, on peut choisir des granulйs dont la
taille est infйrieure а 5 mm Pour la mise en forme d'objets nйcessitant une grande prйcision telles
que les barrettes de chenille on peut aussi utiliser des petits profilйs P de mйlange non vulcanisй,
et dont la section circulaire est de 1 а 10 mm2 Cette derniиre opйration peut tre rйalisйe а titre
d'exemple et tel que reprйsentй sur la figure 2, а l'aide d'une extrudeuse classique 21 dont la
filiиre de sortie 22 comporte plusieurs orifices d'un diamиtre dйterminй pour obtenir des petits
profilйs P de mйlange caoutchouteux et reprйsentйs en pointillйs.
Selon une autre variante de rйalisation du procйdй conforme а l'invention, on peut йgalement
rйaliser la dissociation du mйlange grвce а une coupeuse afin d'obtenir des cubes de faible
dimension.
On choisit la taille des granulйs ou des petits profilйs en fonction du mйlange caoutchouteux et du
produit semi-fini а rйaliser.
On constate qu'il n'est pas nйcessaire pour de nombreux mйlanges d'ajouter des produits anticollants particuliers lors de cette opйration et que les miettes ou granulйs froids n'ont pas tendance
а reprendre en masse. Cependant on peut
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nйanmoins utiliser le procйdй pour des mйlanges caoutchouteux trиs collants, tel que le
caoutchouc naturel, il peut tre alors intйressant de rajouter а l'issus de l'opйration de granulation un
agent anti-collant tel que le stйarate de zinc pour йviter la reprise en masse.
On dose ensuite une quantitй prйdйterminйe de granulйs ou de profilйs. On peut prйvoir, tel que
le montre la figure 2, de verser prйalablement les granulйs ou les profilйs dans une premiиre forme
23 permettant de rйaliser la pesйe et de prйformer par simple dйpфt en couches successives la
masse de profilйs B. Pour diminuer le temps de sйjour dans le moule de compression et avant leur
introduction dans ce dernier, il est йgalement possible de rйaliser un rйchauffage а une
tempйrature de 50 C а 120 C. des granulйs ou profilйs B prйalablement pesйs et dйposйs dans
la forme 23. Les granulйs ou les profilйs B sont alors transfйrйs de la forme 23 dans le moule 41 tel
que reprйsentй sur la figure 4. On veillera а disposer les granulйs ou les petits profilйs B dans le
moule 41 en rйpartissant les granulйs ou les profilйs de sorte а obtenir ensuite une compression
homogиne et sensiblement unidirectionnelle quelle que soit l'йpaisseur comprimйe.
Le moule reprйsentй sur cette figure correspond а un moule de plot mais ne saurait limiter
l'invention а cette forme de moule.
On ferme la porte 42 du moule de compression 41 et on passe alors а la phase de compression du
mйlange dans le moule en rйalisant une montйe en pression et si nйcessaire en tempйrature
L'opйration de compression est rйalisйe dans le cas de l'exemple choisi par l'injection d'un faible
volume complйmentaire de mйlange C. Le complйment de mйlange injectй peut tre de mme
nature ou de nature diffйrente du mйlange qui constitue la masse de granulйs ou de petits profilйs
et n'excиde gйnйralement pas plus de 70 %, et prйfйrentiellement 20%, de la masse totale du
semi-fini achevй.
Dans ces conditions, la masse de granulйs ou de petit profilй est lйgиrement
infйrieure а la masse du semi-fini achevй. Le moule comporte des points d'injection situйs sur une
plaque 44 placйe а la sortie d'un injecteur de mйlange classique 45 ou encore d'une machine
d'extrusion et disposйs judicieusement de maniиre а assurer une mise en compression homogиne
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des granulйs ou des petits profilйs. A titre d'exemple, et sans limiter la portйe de l'invention,
l'injection peut se faire au travers d'une plaque 44 dont la face interne est placйe а la sortie de la
tиte d'extrusion 46 et comportant un grand nombre d'orifices d'injection de diamиtre variables
compris entre 1 et 5 mm. La face externe de la plaque constitue une partie de la face interne du
moule. Ce dispositif permet tout а la foi de mieux rйpartir le complйment de gomme injectй et d'en
limiter le foisonnement au moment du dйmoulage, mais йgalement de faciliter l'opйration de
dйmoulage elle mme en rйduisant la taille individuelle des carottes d'injection.
Les conditions de moulage des miettes ou profilйs P sont les suivantes, pour une durйe sous
pression minimum de l'ordre 1 а 5 minutes, notamment infйrieure а 3mn, voire mme infйrieure а
lmn et de l'ordre de quelques secondes : - la pression hydraulique peut aller jusqu'а 250 bars,
cependant on peut se contenter de pressions trиs infйrieures suivant le rapport de section entre les
pistons hydraulique et de mйlange. Par exemple, l'hydraulique de 50 а 200 bars peut correspondre
а une pression du mйlange dans le moule de 10 а 100 bars, notamment d'environ 30 bars, - on
utilise le moule 41 а tempйrature ambiante ou а chaud, la tempйrature de ce dernier pouvant varier
de 20 C а 150 C, on peut notamment rester aux alentours de 50 C pour la porte 42 ; le rйglage en
tempйrature йtant dйpendant de l'йpaisseur du semi-fini а rйaliser, de la rйpartition de la
tempйrature du produit а comprimer et de ses caractйristiques rhйologiques а l'instant de la
compression.
On peut йgalement rйaliser la mise en compression en utilisant un piston 51 tel que schйmatisй
sur la figure 5.
Enfin, on procиde au dйmoulage. Pour faciliter cette йtape on peut faire appel aux techniques
classiques qui consistent а dйposer sur la surface intйrieure du moule un revtement anticollant, а
introduire de l'air sous pression entre le moule et le mйlange, ou encore а disposer judicieusement
des йjecteurs mйcaniques.
Cette opйration peut tre suivie, notamment en fonction de la nature du mйlange, d'un stockage des
plots ou barrettes 61 ainsi rйalisйs dans des cassettes dimensionnelles dans le but de terminer la
stabilisation de l'objet non vulcanisй 61 en dehors du moule, comme le montre la figure 6. Les
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cassettes sont constituйes par un empilement de plaques 63 sur lesquelles sont glissйes les plots
ou barrettes 61 dйs leur sortie du moule. La distance entre chaque plaque est rйglйe par des cales
ajustables 62, fixйes sur la plaque 63, et dont la hauteur est prйrйglйe de maniиre а obtenir une
cote gйomйtrique constante entre deux plaques. L'expansion du plot ou de la barrette est donc
bloquйe dans la direction perpendiculaire au plan formй par les plaques. Pour assurer une bonne
stabilisation du plot ou de la barrette il suffit de maintenir en position pendant une durйe d'environ
gйnйralement infйrieure а 60 minutes, prйfйrentiellement а 30 minutes.
Cette йtape s'avиre d'autant plus intйressante que l'on souhaite rйduire le temps de passage dans
le moule du mйlange.
L'exemple 2 d'application concerne la rйalisation d'une bande profilйe continue, formйe par la
juxtaposition de portions longitudinales rйalisйes par la mise en oeuvre du procйdй objet de
l'invention. L'usage du procйdй peut s'avйrer particuliиrement intйressant pour la mise en forme
de profilйs constituйs de matйriaux difficilement extrudables.
Selon la figure 1, а partir d'un mйlange caoutchouteux cru vulcanisable au
soufre, qui peut se prйsenter sous forme de plaques 11 ou de bandes continues empilйes, on
rйalise un йmiettage ou broyage dudit mйlange non vulcanisй afin d'obtenir des granulйs ou des
miettes G. On choisit la taille des granulйs en fonction du produit semi-fini а rйaliser. Ainsi on peut
utiliser des granulйs d'une taille infйrieure а 10mm et pour avoir une plus grande prйcision on peut
choisir des granulйs dont la taille est infйrieure а 5mm.
On constate qu'il n'est pas nйcessaire pour de nombreux mйlanges d'ajouter des produits anticollants particuliers lors de cette opйration et que les miettes ou granulйs froids n'ont pas tendance
а reprendre en masse. En effet, comme on l'a dit prйcйdemment, le procйdй est particuliиrement
intйressant pour des mйlanges qui ne sont pas collants.
Tel que reprйsentй sur la figure 7, on pиse sur une bascule 71 une quantitй prйdйterminйe de
granulйs M, dont la masse correspond а la rйalisation d'une portion de profilй. Les granulйs sont
alors acheminйs par une goulotte 72 dans une forme de remplissage 74 reprйsentйe en position
ouverte figure 8 et en position fermйe figure 9, et dont les parois sont constituйes par la face
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supйrieure d'un tapis mйtallique 75 dont l'avance est rйglйe pas а pas, par un couvercle 83
comportant une zone profilйe 81 permettant de disposer les miettes avec un profil transversal de la
surface supйrieure donnй, des parois 82, et par un piston de bourrage 76 dont la fonction est
d'assurer par des va-et-vient successifs un remplissage homogиne de la forme de remplissage. La
pression exercйe sur les miettes par le piston de bourrage 76 est comprise entre 0.2 bars et 1 bar.
Les miettes sont rйparties de sorte а obtenir par la suite une compression homogиne. On entend
par compression homogиne, un taux de compression dans le sens de la course de fermeture des
plateaux de la presse sensiblement йquivalent d'un granulй а l'autre. Ceci impose de disposer les
granulйs sur la surface infйrieure et gйnйralement plane du moule de compression, en faisant en
sorte que le profil dans le sens transversal de la surface supйrieure du dйpфt de granulйs а l'йtat
libre soit sensiblement une homothйtie du profil dans le sens
transversal de la surface supйrieure du dйpфt de granulйs une fois le moule de compression
fermй ; Le rapport d'homothйtie йtant йgal au taux de compression.
Le profil 81 est ajustй pour obtenir un profil transversal des miettes M а l'йtat libre proche du profil
dйsirй tel que schйmatisй sur la figure 10.
Une fois le remplissage de la forme rйalisй, le couvercle 83 est relevй, et le tapis avance d'un pas
correspondant а la longueur de la portion longitudinale. La masse de granulйs prйformйe vient
alors se positionner sous le moule de compression 77 figurй en position ouverte avant la
compression figure 11, en position fermйe figure 12 et en position ouverte aprиs la compression
figure 13.
Le moule de compression 77 est disposй sous une presse 78 comportant un plateau fixe 113 audessus duquel dйfile le tapis 75, un plateau supйrieur mobile 112 coopйrants avec un plateau
infйrieur mobile 115 et un piston hydraulique 114. Les parois du moule de compression sont
constituйes par la surface supйrieure du tapis mйtallique 75 et sur laquelle ont йtй dйposйes les
miettes M prйalablement prйformйes, par les parois 110, et par une zone profilйe 111 fixйe sur la
face infйrieure du plateau supйrieur mobile 112 de la presse 78. Le profil 111 est ajustй pour
obtenir le profil transversal final dйsirй.
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Avantageusement on utilise un moule dйjа chaud afin de ne pas perdre de temps dans les
montйes en tempйrature. On peut йgalement prйvoir un rйchauffage des granulйs avant leur
introduction dans le moule pour diminuer le temps de sйjour dans le moule.
Aprиs positionnement des miettes sous la presse, on abaisse le plateau supйrieur 112 de la presse,
et on passe а la phase de compression en rйalisant une montйe en pression et en tempйrature
(figure 12).
Les conditions de moulage des miettes sont les suivantes, pour une durйe sous pression minimum
de l'ordre de 3 а 5mn voire mme infйrieure а 3mn, notamment dans le cas oщ l'on rйaliserait un
prйchauffage des miettes а une
tempйrature infйrieure а la tempйrature de vulcanisation comprise entre 50 et 120 C, et dans le
cas de l'exemple proposй qui s'йtablit aux environs de 70 C : - la pression peut aller jusqu'а 160
bars cependant on peut se contenter de pressions bien infйrieures de l'ordre de 30 а 40 bars, - la
tempйrature du moule peut varier de 70 C а 150 C environ. On peut notamment rester entre 110 et
150 C. Et pour beaucoup de mйlanges peu collants, la tempйrature peut rester voisine de 130 а
140 C, le rйglage en tempйrature йtant dйpendant de l'йpaisseur du semi-fini а rйaliser.
Enfin, on procиde а la remontйe du plateau 111. Le tapis 75 peut alors tre avancй а nouveau de la
longueur d'un pas correspondant а la longueur d'une portion longitudinale.
La liaison de deux portions longitudinales successives M et M's'effectue de maniиre avantageuse
en faisant en sorte que les sections S et S'des deux extrйmitйs contiguлs de M et de M'soient
mises en contact pendant la phase de remplissage de la portion M et pendant la phase de
compression de la portion M'.
Lors du de la phase de compression de la portion M on s'arrange pour que la zone d'interface entre
M et M'demeure sous la presse de maniиre а assurer un aboutage rйsistant des deux extrйmitйs.
La juxtaposition successive dans le sens longitudinal de plusieurs portions semblables permet
d'obtenir une bande B continue qu'il est facile de mettre en oeuvre au cours une йtape de
confection ou de finition d'un pneumatique et non dйcrite dans le prйsent document.
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Compte tenu de la faible йpaisseur relative du profilй, il n'est gйnйralement pas nйcessaire de
procйder а une йtape de stabilisation du produit par blocage de l'expansion.Claims:
REVENDICATIONS 1. Procйdй de mise en forme d'au moins un produit semi-fini а partir d'un ou
plusieurs mйlanges а base d'йlastomиres diйniques vulcanisable au soufre qui associe les
йlйments suivants : - dissociation dudit mйlange non vulcanisй pour obtenir de petits йlйments
unitaires, - rйpartition d'une masse prйdйterminйe desdits йlйments unitaires а l'йtat non
vulcanisй dans un moule de mise en forme, - fermeture du moule et compression desdits йlйments
unitaires dans le moule de mise en forme, - dйmoulage du semi-fini non vulcanisй ainsi rйalisй.
2. Procйdй selon la revendication 1, dans lequel les йlйments unitaires de mйlange sont
rйchauffйs avant d'tre introduits а chaud dans le moule.
3. Procйdй selon la revendication 2, dans lequel le rйchauffage des йlйments unitaires de
mйlange s'effectue а une tempйrature comprise entre 50 et 120 C.
4. Procйdй selon l'une quelconque des revendications 1 а 3, dans lequel, а l'issue du dйmoulage,
les produits semi-finis rйalisйs sont stockйs dans des cassettes afin de terminer leur stabilisation.
5. Procйdй selon l'une quelconque des revendications 1 а 4, dans lequel la dissociation est
rйalisйe par broyage du mйlange jusqu'а ce que les йlйments unitaires de mйlange aient un
diamиtre moyen infйrieur ou йgal а 10 mm.
6. Procйdй selon la revendication 5, dans lequel on poursuit l'opйration de dissociation jusqu'а ce
que les йlйments unitaires de mйlange aient un diamиtre moyen infйrieur ou йgal а 5 mm.
7. Procйdй selon l'une quelconque des revendications 1 а 4, dans lequel la dissociation est
rйalisйe par extrusion du mйlange en profilйs, continus ou discontinus, de section comprise entre
1 et 10mm2.
288/425
8. Procйdй selon l'une quelconque des revendications 1 а 4, dans lequel la dissociation est
rйalisйe par une coupeuse du mйlange en cubes de faible dimension.
9. Procйdй selon l'une quelconque des revendications 1 а 8, dans lequel les йlйments unitaires de
mйlange sont versйs dans un moule avec une rйpartition contrфlйe des йlйments unitaires de
mйlange assurant lors de la fermeture du moule le respect dans ce dernier d'un taux de
compression sensiblement constant et unidirectionnel desdits йlйments.
10. Procйdй selon l'une quelconque des revendications 1 а 9, dans lequel les йlйments unitaires
de mйlange sont versйs dans un moule dйjа chaud.
11. Procйdй selon l'une quelconque des revendications 1 а 10, dans lequel la tempйrature du
moule pendant la compression est comprise entre 20 C et 150 C.
12. Procйdй selon l'une quelconque des revendications 1 а 11, dans lequel la pression dans le
moule lors de la compression est comprise entre 10 et 100 bars.
13. Procйdй selon la revendications 12, dans lequel la pression dans le moule lors de la
compression est comprise entre 20 et 40 bars 14. Procйdй selon l'une quelconque des
revendications 1 а 13, dans lequel la durйe de la compression est de l'ordre de quelques secondes
а quelques minutes.
15. Procйdй selon la revendication 14, dans lequel la durйe de la compression est comprise entre
1 а 5 minutes.
16. Procйdй selon l'une quelconque des revendications 1 а 15 caractйrisй en ce que la phase de
compression est assurйe par l'injection d'un volume complйmentaire de mйlange de mme nature
ou de nature diffйrente de celle du mйlange qui constitue la masse de granulйs ou de petits
profilйs.
289/425
17. Procйdй selon la revendication 16 caractйrisй en ce que la masse du volume complйmentaire
injectй est comprise entre 0 et 70% de la masse totale du semi- fini achevй.
18. Procйdй selon la revendication 17 caractйrisй en ce que la masse du volume complйmentaire
injectй est comprise entre 15 et 30% de la masse totale du semi- fini achevй.
19. Procйdй selon l'une quelconque des revendications 1 а 15 caractйrisй en ce que la phase de
compression est assurйe par un piston.
20. Procйdй selon l'une quelconque des revendications 1 а 15 caractйrisй en ce que la phase de
compression est assurйe par une presse coopйrant avec un moule.
21. Procйdй de rйalisation d'une bande profilйe а base de mйlange caoutchouteux continue,
caractйrisй en ce que la bande est constituйe d'une juxtaposition d'йlйments longitudinaux
rйalisйs selon l'une quelconque des revendications 1 а
15.
290/425
33. WO03064523 - 31.07.2003
PROCESS FOR THE PREPARATION OF A THERMOPLASTIC ELASTOMER COMPRISING A
PARTIALLY VULCANIZED RUBBER CONCENTRATE
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO03064523
Inventor(s):
WANG YUNDONG [US] (--); BRZOSKOWSKI RYSZARD [US] (--)
Applicant(s):
DSM NV [US] (--)
IP Class 4 Digits: C08K; C08L
IP Class:
C8L1/00; C8K3/00
E Class: C08L23/16+B2; C08L71/12B+B2; C08L79/08+B2A; C08L81/02+B2; C08L81/06+B2
Application Number:
US20020058058 (20020129)
Priority Number: US20020058058 (20020129)
Family: EP1470187
Equivalent:
EP1470187
Abstract:
PROCESS FOR THE PREPARATION OF A THERMOPLASTIC ELASTOMER BY MELT MIXING A
PARTIALLY VULCANIZED RUBBER CONCENTRATE, A THERMOPLASTIC POLYMER AND/OR
ADDITIVES, OPTIONALLY OIL AND A CURING AGENT. THE PARTIALLY VULCANIZED RUBBER
CONCENTRATE IS PREPARED BY MELT MIXING AT LEAST ONE ELASTOMER AND OPTIONALLY
OIL WITH A THERMOPLASTIC POLYMER AND A CURING AGENT. THE ELASTOMER MAY BE
EPDM OR EPM. THE THERMOPLASTIC POLYMER MAY BE CHOSEN FROM A THERMOPLASTIC
POLYOLEFINE. USEFULL CURING AGENTS ARE FOR EXAMPLE SULFUR, SULFUROUS
COMPOUNDS, METAL OXIDES, MALEIMIDES, PHENOL RESINS OR PEROXIDES.Description:
[0001] The invention relates to a process for the preparation of a thermoplastic elastomer.
291/425
[0002] A process for the preparation of thermoplastic elastomers is for example known from
"Compounding of rubber Concentrate Thermoplastic Vulcanizates" by Terry M. Finerman, Ph.D., Luc
Vandendriessche, Joseph E. Pfeiffer, presented at the Society of Plastics Engineers Topical
Conference TPEs 2000, Sep. 28-29, 1999. Described is the preparation of fully vulcanized rubber
concentrates and of thermoplastic elastomers by melt mixing the fully vulcanized rubber
concentrates with ingredients such as oil, filler, stabilizers, processing aids and thermoplastic
polymers for example polypropylene or polyethylene. The thus obtained thermoplastic elastomers
have the disadvantage that their mechanical properties are not sufficient for some applications for
example in automotive, building and construction, mechanical rubber goods or consumer products.
For example the tensile strength value of those thermoplastic elastomers is relatively low and
therefore not meeting the required automotive material specifications. Another disadvantage of the
above process is that the preparation of fully cured rubber concentrates with consistent properties
and good morphology is difficult because of the high concentration of elastomeric phase and the
minor concentration of thermoplastic phase.
[0003] The object of the present invention is to completely or largely eliminate the stated drawbacks.
[0004] This object is achieved in that the thermoplastic elastomer is prepared by melt mixing:
[0005] a. a partially vulcanized rubber concentrate
[0006] b. a thermoplastic polymer and/or additives
[0007] c. optionally oil and
[0008] d. a curing agent.
[0009] Surprisingly the process of the present invention provides the preparation of thermoplastic
elastomers with improved mechanical properties which meet the stringent material specifications
needed for some applications in automotive, building and construction, mechanical rubber goods or
consumer products. A further advantage is that the elastic properties of the thermoplastic elastomer
are improved. Moreover the thermoplastic elastomers show an improved fluid resistance. Yet another
advantage is that thermoplastic elastomers may be prepared with a better compression set.
[0010] The partially vulcanized rubber concentrate (a) is prepared by melt mixing:
[0011] e. at least one elastomer and optionally oil
[0012] f. at least one thermoplastic polymer
[0013] g. a curing agent.
[0014] The elastomer(s) and optionally oil and the thermoplastic polymer(s) are melt mixed and
kneaded above the melting point of the thermoplastic polymer whereby the elastomer is vulcanized
during mixing and kneading. This process is also known as a dynamic vulcanization process.
[0015] The elastomer (e) may be any elastomer capable of being vulcanized by the curing agent.
Examples of elastomer(s) are ethylene-propylene copolymers, hereinafter called EPM, ethylene-
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propylene-diene terpolymers, hereinafter called EPDM, acrylonitrile-butadiene rubber, styrenebutadiene rubber, isobutene-isoprene rubber, styrene-ethylene/styrene-butadiene block copolymers,
butyl rubber, isobutylene-p-methylstyrene copolymers or brominated isobutylene-p-methylstyrene
copolymers or natural rubber. Preferably, the elastomer in the partially vulcanized rubber concentrate
according to the invention is an olefinic elastomer. It is especially preferred to use EPM or EPDM as
elastomer. More preferably, EPDM is used as elastomer. The EPDM preferably contains 50-70 parts
by weight ethylene monomer units, 48-30 parts by weight alpha-olefin monomer units and 1-12 parts
by weight monomer units originating from a non-conjugated diene or combinations of more than one
non-conjugated diene. Preferably the alpha-olefin is propylene. As non-conjugated diene use is
preferably made of dicyclopentadiene (DCPD), 5-ethylidene-2- norbornene (ENB) or vinylnorbornene
(VNB). The elastomer(s) may be prepared for example with a Ziegler-Natta catalyst, a metallocene
catalyst or a single site catalyst.
[0016] The elastomer for example comprises between 0-250 parts of oil per 100 parts of elastomer.
Preferably comprises between 20-200 parts per 100 parts of elastomer. It is especially preferred to
comprise between 30-160 parts of oil per 100 parts of elastomer. Any known oil may be used,
examples of oils are processing oils for example paraffinic, naphtalenic or aromatic oil or
isoparaffinic oil which is also known as polyalfaolefinic oil. Preferably a highly hydrogenated oil
obtained by a hydrocracking and isodewaxing process is used, for example PennzUltra, 1199,
supplied by Pennzoil in the United States of America. The point in time at which the oil is metered is
not critical. In the process, the oil is for example added before, during or after the dynamic
vulcanisation of the elastomer. It is also possible that the oil is added partly before and partly during
and/or after the dynamic vulcanisation of the elastomer. It is also possible that the elastomer has
been pre-mixed with the desired quantity of oil or a proportion thereof. In fact a person skilled in the
art can adjust the ratio of elastomer(s)/thermoplastic polymer(s)/oil to achieve partially vulcanized
rubber concentrates with a low hardness. The partially vulcanized rubber concentrate for example
has a hardness of 70 shore A or lower measured according to ASTM D-2240. Preferably the
hardness is 60 shore A or lower. Most preferably the hardness is 50 shore A or lower.
[0017] Examples of suitable thermoplastic polymers (f) which may be used in the preparation of the
partially vulcanized rubber concentrates are thermoplastic polyolefin homo- and copolymers or
blends thereof. For example homopolymers of ethylene or propylene, copolymers of ethylene and
propylene, copolymers of ethylene and an alpha-olefin comonomer with 4-20 carbon atoms or
copolymers of propylene and an alpha-olefin comonomer with 4-20 carbon atoms. In case of a
copolymer, the content of propylene in said copolymer is preferably at least 75% by weight. The
thermoplastic polyolefin homo- and copolymers may be prepared with a Ziegler-Natta catalyst, a
metallocene catalyst or with another single site catalyst. Also suitable thermoplastic polymers are for
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example reactor thermoplastic polyolefine elastomers (TPO's), polyamides, polycarbonate,
polyesters, polysulfones, polylactones, polyacetals, acrylonitrile-butadiene-styrene (ABS) resins,
polyphenylene oxide (PPO), polyphenylene sulfide (PPS), styrene-acrylonitrile (SAN) resins,
polyimides, styrene maleic anhydride (SMA) and aromatic polyketones. It is possible to use more
than one thermoplastic polymer in the preparation of the partially vulcanized rubber concentrates.
[0018] Preferably, a polypropylene homopolymer is used as thermoplastic polymer. The
polypropylene may be atactic, isotactic, syndiotactic or a physical and chemical mixture thereof. The
term chemical mixture means that the polypropylene may have atactic, isotactic or syndiotactic
structures randomly or in blocks along the molecular chains. The polypropylene homopolymer may
be linear or branched. The Melt flow index (MFI) of the polypropylene preferably is between 0.3 and
50; more preferably below 20 (according to ISO norm 1133 (230[deg.] C.; 2.16 kg load)).
[0019] Examples of suitable curing agents (g) include sulfur, sulfurous compounds, metal oxides,
maleimides, phenol resins and peroxides. The curing agents may be used with or without
accelerators. Said curing agents are for example described in U.S. Pat. No. 5,100,947. It is also
possible to use siloxane compounds as curing agent, for example hydrosilane or vinylalkoxysilane.
The elastomer is preferably vulcanized with a phenol resin, a siloxane or a peroxide. Examples
suitable accelerators are sulphur, ethylene dimethylacrylate, polyethylene glycol dimethylacrylate,
trimethylol propane trimethacrylate, divinyl benzene, diallyl itaconate, triallyl cyanurate, diallylphtalate,
allyl methacrylate, cyclohexyl methacrylate and m-phenylene bismaleimide.
[0020] The amount of curing agent, the accelerator, the temperature and the time of vulcanisation are
selected in order to obtain the desired degree of vulcanization. Preferably the amount of curing agent
is between 0.1-10 parts by weight per 100 parts by weight of elastomer. More preferably the amount
of curing agent is between 0.1-5 parts by weight per 100 parts by weight of elastomer.
[0021] The degree of vulcanization of the elastomer can be expressed in terms of gel content or
conversely, extractable components. The gel content is the ratio of the amount of non-soluble
elastomer and the total amount of elastomer (in weight) of a specimen soaked in an organic solvent
for the elastomer. The method is described in U.S. Pat. No.4,311,628 and U.S. Pat. No.5,100,947. In
general terms a specimen is soaked for 48 hours in an organic solvent at temperatures suitable for
the thermoplastic polymer and the elastomer. The solvent should be capable of dissolving the
thermoplastic polymers completely at the temperature of gel test. After weighing of both the
specimen and the residue the amount of non-soluble elastomer and total elastomer are calculated,
based on knowledge of the relative amounts of all components in the composition. The elastomer in
the rubber concentrate is partially vulcanized. Partially vulcanized means that the elastomer may be
vulcanized to a relatively low degree as long as there is no problem with pellet stickiness. Preferably
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the elastomer in the partially vulcanized rubber concentrate has a gel content higher than 50%. More
preferably a gel content higher than 70%.
[0022] The partially vulcanized rubber concentrate is preferably prepared by melt mixing between
30-95 parts by weight of the elastomer(s), between 0-70 parts by weight of oil, between 5-50 parts by
weight of the thermoplastic polymer(s), between 0.1-10 parts by weight of the curing agent per 100
parts by weight of elastomer, whereby the sum of the parts by weight of the elastomer(s),
thermoplastic polymer(s), curing agent and oil is 100. More preferably the amount of elastomer(s)
varies between 35-90 parts by weight, the amount of oil varies between 5-60 parts by weight, the
amount of curing agent varies between 0.1-5 parts by weight per 100 parts by weight of elastomer
and the amount of thermoplastic polymer(s) varies between 5-40 parts by weight, whereby the sum
of the parts by weight of the elastomer(s), thermoplastic polymer(s), curing agent and oil is 100. Most
preferably the amount of elastomer(s) varies between 40-85 parts by weight, the amount of oil varies
between 10-50 parts by weight, the amount of curing agent is between 0.1-5 parts by weight per 100
parts by weight of elastomer and the amount of thermoplastic polymer(s) varies between 5-30 parts
by weight, whereby the sum of the parts by weight of the elastomer(s), thermoplastic polymer(s),
curing agent and oil is 100.
[0023] The process for the preparation of the thermoplastic elastomer according to present invention
comprises melt mixing
[0024] a. the partially vulcanized rubber concentrate
[0025] b. a thermoplastic polymer and/or additives
[0026] c. optionally oil and
[0027] d. a curing agent.
[0028] The melt mixing may be carried out in conventional mixing equipment for example roll mills,
Banbury mixers, Brabender mixers, continuous mixers for example a single screw extruder, a Buss
kneader, Ferro continuous mixer (FCM) and a twin screw extruder. Preferably melt mixing is carried
out in a twin screw extruder with sufficient mixing efficiency, good temperature control and residence
time control. By the use of a twin-screw extruder good tensile properties are achieved. More
preferably the melt mixing is carried out in a single screw extruder. By the use of a single screw
extruder better compression set values may be achieved. The use of a single or twin screw extruder
depends on the desired properties the thermoplastic elastomer should have.
[0029] The partially vulcanized rubber concentrate, the thermoplastic polymer and/or the additives,
the oil and the curing agent may be dry blended prior to the melt mixing. Alternatively the partially
vulcanized rubber concentrate, the thermoplastic polymer and/or the additives, the oil and the curing
agent may be directly fed by feeders to the continuous mixer.
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[0030] Examples of the thermoplastic polymers (b) which may be melt mixed with the partially
vulcanized rubber concentrate (a) are chosen from the above described thermoplastic polymers (f).
The choice of the thermoplastic polymer in terms of melt flow index or viscosity depends on the end
applications. A person skilled in the art may select the thermoplastic polymer with proper molecular
weight, molecular weight distribution or molecular structure to achieve the thermoplastic elastomer
with balanced properties.
[0031] Examples of oils (c) which may be used in the process of the present invention are
processing oils for example paraffinic, naphtalenic or aromatic oil or isoparaffinic oil which is also
known as polyalfaolefinic oil. Preferably a highly hydrogenated oil obtained by a hydrocracking and
isodewaxing process is used, for example PennzUltra, 1199, supplied by Pennzoil in the United
States of America. The point in time at which the oil is metered is not critical. In the process, the oil is
for example added before, during or after the dynamic vulcanisation of the thermoplastic elastomer.
It is also possible that the oil is added partly before and partly during and/or after the dynamic
vulcanisation of the thermoplastic elastomer.
[0032] Examples of the suitable curing agents (d) are described above as the curing agents (g). The
curing agent may be in powder form, in liquid form or may be soluble in a liquid. If the curing agent is
in powder form the partially vulcanized rubber concentrate pellets may first be coated with a
processing oil and then blended with the curing agent powder prior to melt mixing with the
thermoplastic polymers. If the curing agent is in liquid form, it may be dry mixed with the partially
vulcanized rubber concentrate prior to melt mixing with the thermoplastic polymer and/or the
additives. If the curing agent is soluble in a liquid for example in processing oil or a solvent it may
first be dissolved in the liquid and then coated onto the rubber concentrate pellets prior to melt
mixing with the thermoplastic polymers. Alternatively, liquid curing agent, curing agent solution in oil
or solvent, or curing agent melt can be dosed or injected directly to the mixer in the form of a liquid
or liquid solution.
[0033] Examples of additives which may be melt mixed are reinforcing and non-reinforcing fillers,
plasticizers, antioxidants, stabilizers, processing oil, antistatic agents, waxes, foaming agents,
pigments, flame retardants and other known agents described in for example the Rubber World
Magazine Blue Book. Examples of fillers that may be used are calcium carbonate, clay, silica, talc,
titanium dioxide, and carbon. Another additive that may optionally be used in the thermoplastic
elastomer is a Lewis base for example a metal oxide, a metal hydroxide, a metal carbonate or
hydrotalcite. The quantity of additive to be added is known to one skilled in the art.
[0034] In the process of the present invention it is also possible to prepare the thermoplastic
elastomer by melt mixing the partially vulcanized rubber concentrate, additives and curing agent
without the thermoplastic polymer. In this case suitable additives are viscosity modifiers, low friction
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coefficient additives such as silicon oil and fatty amide lubricants, tackifiers or the additives as
described above. The amount of additives is for example between 0.5-15 parts by weight relative to
the total quantity of the thermoplastic elastomer. Preferably the amount of additives is between 1-10
parts by weight relative to the total quantity of thermoplastic elastomer. More preferably the amount
of additives is between 2-8 parts by weight relative to the total quantity of the thermoplastic elastomer.
[0035] The gel content of the thermoplastic elastomer according to the present invention may vary
between 60 and 100%. Preferably, the gel content is in excess of 80%. More preferably, the gel
content is in excess of 90%. Most preferable the gel content is in excess of 97%.
[0036] The process of the present invention comprises the preparation of the thermoplastic
elastomer by melt mixing for example:
[0037] a. 10-90 parts by weight of the partially vulcanized rubber concentrate
[0038] b. 90-10 parts by weight of a the thermoplastic polymer and/or additives
[0039] c. 0-30 parts by weight of oil
[0040] d. 0.1-10 parts by weight of the curing agent
[0041] whereby the sum of the parts by weight of the partially vulcanized rubber concentrate, the
thermoplastic polymer and/or additives, the oil and the curing agent is 100.
[0042] Preferably the thermoplastic elastomer is prepared by melt mixing
[0043] a. 15-70 parts by weight of the partially vulcanized rubber concentrate
[0044] b. 30-85 parts by weight of a the thermoplastic polymer and/or additives
[0045] c. 0-30 parts by weight of oil
[0046] d. 0.1-5 parts by weight of the curing agent
[0047] whereby the sum of the parts by weight of the partially vulcanized rubber concentrate, the
thermoplastic polymer and/or additives, the oil and the curing agent is 100.
[0048] The process of the present invention may be carried out in two stages. In a first stage, the
partially vulcanized rubber concentrate may be prepared whereby at least one elastomer is partially
vulcanized in the presence of at least one thermoplastic polymer using appropriate curing agents. In
a second stage the partially vulcanized rubber concentrate, the appropriate thermoplastic polymer
and/or additives are melt-mixed in the presence of the curing agent to iniate a further dynamic
vulcanization. The curing agents used in the first and in the second stage may be the same or
different curing agents. Preferably the same curing agent is used in the two stages.
[0049] The two stages can be carried out independently in separate steps or sequentially in the
same processing equipment. After dynamic vulcanization the thermoplastic elastomer may be
pelletized. The thermoplastic elastomer may however also be directly fed in molten stage to next
processing equipment for example through a die. In such case the continuous mixer is attached with
the die or other necessary downstream equipment and acts not only as mixer but at the same time as
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a melting and a conveying equipment for processes as foaming, film and sheet extrusion, profile
extrusion, film and sheet calendering or co-extrusion.
[0050] The additives may be added during the preparation of the partially vulcanized rubber
concentrate or during the preparation of the thermoplastic elastomer or both.
[0051] The thermoplastic elastomer prepared by the process according to the present invention may
be used in automotive, building and construction, mechanical rubber goods or consumer products.
[0052] The present invention will be further explained by the following examples without being limited
thereto. The measurements in the examples were carried out using the following tests:
[0053] Hardness ASTM D-2240, 5 sec delay
[0054] Tensile strength, ASTM D-412, Die C
[0055] Ultimate Elongation, ASTM D-412, Die C
[0056] 100% modulus, ASTM D-412, Die C
[0057] Tear strength, ASTM D-624, Die C
[0058] Compression set, 22 hrs@ 70C % ASTM D-395, method B
[0059] Compression set, 70 hrs@125C % ASTM D-395, Method B
[0060] Oil swell, 70 hrs@125C, ASTM D-471
EXAMPLE 1
[0061] A partially vulcanized rubber concentrate (compound 1) was prepared in a 92 mm
WernerPfleiderer intermeshing co-rotating twin-screw extruder by melt mixing and kneading 67.1
parts by weight Keltan P597(TM) (50 wt % oil-extended EPDM) with 7.7 parts by weight
polypropylene homopolymer PP 1012(TM) (MFI=1.2) as thermoplastic polymer, 25.2 parts by weight
of Sunpar 150C(TM) processing oil, 0.3 wt % phenolic resin SP1045(TM) and 0.3 wt % stannous
chloride dihydrate activator. The properties of compound 1 are shown in table 1.
TABLE 1
PropertiesTest value
Hardness, Shore A 41
Tensile strength, Mpa 3,1
Elongation %424
100% Modulus, Mpa 1
Tear Strength, kN/m11,6
Compression set, 22 hrs@70 C., % 25
Compression set, 70 hrs@125 C., %35,5
Oil swell in IRM 903, 70 hrs@125 C., %125
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EXAMPLE 2
[0062] A thermoplastic elastomer (compound 2) was prepared of compound 1 pellets and a
polypropylene homopolymer 31S07A (MFI=0.7) without the addition of phenolic resin SP1045(TM) as
curing agent. Compound 2 was prepared on a 25 mm Berstorff intermeshing co-rotating twin screw
extruder.
EXAMPLE 3
[0063] A thermoplastic elastomer (compound 3) was prepared of compound 1 pellets and a
polypropylene homopolymer 31S07A (MFI=0.7) with the addition of phenolic resin SP1045(TM) as
curing agent.
[0064] To prepare compound 3, the compound 1 pellets were first coated with a small amount of
processing oil Sunpar 150C(TM) and then blended with SP1045 powder in a cement mixer before the
polypropylene homopolymer 31S07a was introduced. All ingredients were further dry blended using
a cement mixer prior to the melt mixing.
[0065] Compound 3 was prepared on a on a 25 mm Berstorff intermeshing co-rotating twin screw
extruder.
EXAMPLE 4
[0066] A thermoplastic elastomer (compound 4) was prepared according to example 3 except that a
1.5 inch Killion single screw extruder with l/d ratio of 24/1 was used.
[0067] After melt mixing, melt strands were cooled in a cold water bath before being pelletized. All
compounds were dried for at least three hours to remove any residual moisture prior to injection
molding.
[0068] 4*4 cm plaques with a thickness of 3 mm were used for testing the mechanical properties.
The results are shown in table 2
TABLE 2
Compound 2Compound 3Compound 4
Parts byParts byParts by
weightweightweight
compound 158,6 58 58
PP homopolymer 31S07A41,441,241,2
Sunpar 150C(TM) 0,2 0,2
phenolic resin 0,6 0,6
SP1045(TM)
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Hardness Shore D39,4 4139,1
Tensile strength, MPa14,818,213,3
Ultimate Elongation, %728580493
100% modulus, MPa 8,8 9,8 8,6
Tear strength, kN/m73,373,6 67
Compression set,57,552,345,3
22 hrs@ 70 C., %
Compression set,76,769,1 68
22 hrs@ 125 C., %
Oil swell in IRM 903,44,4 3236,7
70 hrs@ 125 C., %
[0069] Table 2 shows that the thermoplastic elastomers prepared by the process of the present
invention have good mechanical properties.
[0070] Moreover it is clear that the use of a twin-screw extruder leads to better mechanical properties
whereas the use of a single screw extruder leads to better compression set values. In addition, the
use of the curing agent in the preparation of compounds 3 and 4 shows improved fluid resistance as
indicated by the lower oil swell values in comparison to the control compound 2.Claims:
1. Process for the preparation of a thermoplastic elastomer by melt mixing
a. a partially vulcanized rubber concentrate
b. a thermoplastic polymer and/or additives
c. optionally oil and
d. a curing agent.
2. Process according to claim 1 characterized in that the melt mixing is carried out in a twin-screw
extruder.
3. Process according to claim 1 characterized in that the melt mixing is carried out in a single screw
extruder.
4. Process according to any one of the claims 1-3 characterized in that the partially vulcanized
rubber concentrate (a) is prepared by melt mixing:
e. at least one elastomer and optionally oil
f. at least one thermoplastic polymer
g. a curing agent.
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5. Process according to claim 4 characterized in that the partially vulcanized rubber concentrate is
prepared by melt mixing
e. 30 to 95 parts by weight of the elastomer(s) and 0-70 parts by weight of oil
f. 5 to 50 parts by weight of the thermoplastic polymer(s)
g. 0.1-10 parts by weight of the curing agent
whereby the sum of the parts by weight of the elastomer(s), the thermoplastic polymer(s), curing
agent and oil is 100.
6. Process according to any one of claims 4-5 characterized in that the elastomer is EPDM or EPM.
7. Process according to claim 1-6 characterized in that the thermoplastic polymer is chosen from
thermoplastic polyolefin homo- and copolymers, reactor TPO, polyamides, polycarbonate, polyesters,
polysulfones, polylactones, polyacetals, acrylonitrile-butadiene-styrene (ABS) resins, polyphenylene
oxide (PPO), polyphenylene sulfide (PPS), styrene-acrylonitrile (SAN) resins, polyimides, styrene
maleic anhydride (SMA) and aromatic polyketones.
8. Process according to claim 7 characterized in that the thermoplastic polymer is a thermoplastic
polyolefin homo- and copolymer.
9. Process according to claim 8 characterized in that the thermoplastic polymer is a polypropylene
homopolymer.
10. Process according to any one of claims 1-9 characterized in that the elastomer in the partially
vulcanized rubber concentrate has a gel content higher than 50%.
11. Process according to any one of claims 1-10 characterized in that the elastomer in the partially
vulcanized rubber concentrate has a gel content higher than 70%.
12. Process for the preparation of a thermoplastic elastomer according to claims 1-11 by melt mixing:
a. 10-90 parts by weight of the partially vulcanized rubber concentrate
b. 90-10 parts by weight of a the thermoplastic polymer and/or additives
c. 0-30 parts by weight of oil
d. 0.1-10 parts by weight of the curing agent
whereby the sum of the parts by weight of the partially vulcanized rubber concentrate, the
thermoplastic polymer and/or additives, the oil and the curing agent is 100.
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13. Process according to any one of claims 1-12 characterized in that the curing agent is chosen
from phenol resins, siloxanes or peroxides.
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34. WO03082939 - 22.12.2004
LATEX, FLUID TREATMENTS FOR BONDING, FIBROUS MEMBERS, AND COMPOSITE MEMBERS
CONSISTING OF FIBROUS MEMBERS AND VULCANIZED RUBBER MEMBERS
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO03082939
Inventor(s):
NAKAMURA MASAYUKI [JP] (--); KAWANAKA TAKAFUMI [JP] (--)
Applicant(s):
ZEON CORP [JP] (--)
IP Class 4 Digits: C08L; C08F
IP Class:
C8F236/12; C8L9/04
E Class: C08L9/04; C09D109/04+B4
Application Number:
EP20030715518 (20030327)
Priority Number: WO2003JP03841 (20030327); JP20020090921 (20020328)
Family: EP1489115
Equivalent:
JP2003286318
Abstract:
A LATEX OF A CYANO-BEARING COPOLYMER RUBBER WHICH CONTAINS UNITS DERIVED
FROM AN ALPHA , BETA -ETHYLENICALLY UNSATURATED NITRILE MONOMER IN AN AMOUNT
OF 10 TO 30 % BY MASS AND HAS AN IODINE NUMBER OF 250 OR BELOW, A MOONEY
VISCOSITY (ML1+4, 100 DEG C) OF 10 TO 120, AND A DIFFERENCE ( DELTA TG) BETWEEN
EXTRAPOLATED GLASS TRANSITION INITIATION TEMPERATURE (TIG) AND EXTRAPOLATED
GLASS TRANSITION ENDING TEMPERATURE (TEG) OF 15 DEG C OR BELOW AS DETERMINED
BY DIFFERENTIAL SCANNING CALORIMETRY; AND FLUID TREATMENTS FOR BONDING AND
ADHESIVE COMPOSITIONS, CONTAINING THE LATEX. THE ADHESIVE COMPOSITIONS ARE
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EXCELLENT IN HEAT RESISTANCE, OIL RESISTANCE, AND ADHESION TO VULCANIZED
RUBBERS, AND EXHIBIT TACKINESS.Description:
Technical Field
[0001] The present invention relates to a fluid treatment for bonding (an adhesive treatment solution)
forming an adhesive composition layer excellent in adhesion between a fibrous member(a fiber
member) and a vulcanized rubber member and having sufficient tackiness, a fiber member treated
with the adhesive treatment solution, and a composite member of the fiber member and a vulcanized
rubber member.
Background Art
[0002] In recent years, nitrile group-containing copolymer rubber having a low iodine value,
represented by hydrogenated acrylonitrile-butadiene copolymer rubber, attracts attention. This nitrile
group-containing copolymer rubber is superior in heat resistance and oil resistance to general nitrile
group-containing copolymer rubber having many carbon-carbon unsaturated bonds in a main chain
structure such as acrylonitrile-butadiene copolymer rubber.
[0003] An adhesive composition containing a latex of this nitrile group-containing copolymer
rubber is excellent in heat resistance, oil resistance and adhesion to the surface of vulcanized rubber.
Accordingly, it is proposed that by making a composite of a fiber member treated with this adhesive
composition and a vulcanized rubber member, a member excellent in mechanical strength is
obtained (Japanese Patent Application Laid-Open No. 8-100085). For example, when this adhesive
composition is used in producing a belt by combining a glass core wire produced by twisting glass
fibers with a belt substrate of vulcanized, nitrile group-containing copolymer rubber, a belt having the
glass core wire bonded strongly to the belt substrate can be formed.
[0004] However, this adhesive composition is poor in tackiness, and production of a belt by using
this adhesive composition is problematic. That is, the adhesive composition is poor in tackiness, and
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thus there is a possibility that glass fibers in the glass core wire are easily untied due to loading
applied in using the belt, and the untied brittle fibers are cut and the whole of the glass core wire is
cut.
Disclosure of the Invention
[0005] The object of the present invention is to provide an adhesive composition which is excellent
in heat resistance and oil resistance, is superior in adhesion to vulcanized rubber, and has tackiness.
[0006] The present inventors made extensive study to solve the problem, and as a result, they
found that an adhesive composition prepared from a latex of nitrile group-containing copolymer
rubber having a specific composition of the copolymer and showing a small temperature difference
between extrapolated glass transition initiation temperature (Tig) and extrapolated glass transition
end temperature (Teg) measured by differential scanning calorimetry is excellent in adhesiveness
and strongly bonds a fiber member to a vulcanized rubber member, and on the basis of this finding,
the present invention was completed.
[0007] According to a first aspect of the invention, there is provided a latex of nitrile groupcontaining copolymer rubber containing 10 to 30 mass% alpha , beta -ethylenically unsaturated
nitrile monomer unit, having an iodine value of 250 or less and a Mooney viscosity (ML1+4, 100 DEG
C) of 10 to 120, and showing a temperature difference of 15 DEG C or less between extrapolated
glass transition initiation temperature (Tig) and extrapolated glass transition end temperature (Teg)
measured by differential scanning calorimetry. According to a second aspect of the invention, there
is provided an adhesive treatment solution comprising the latex and a resorcinol/formaldehyde resin.
According to a third aspect of the invention, there is provided an adhesive composition comprising a
resorcinol/formaldehyde resin and nitrile group-containing copolymer rubber particles containing 10
to 30 mass% alpha , beta -ethylenically unsaturated nitrile monomer unit, having an iodine value of
250 or less and a Mooney viscosity (ML1+4, 100 DEG C) of 10 to 120, and showing a temperature
difference of 15 DEG C or less between extrapolated glass transition initiation temperature (Tig) and
extrapolated glass transition end temperature (Teg) measured by differential scanning calorimetry.
According to a fourth aspect of the invention, there is provided a fiber member comprising a layer of
the adhesive composition formed on at least a part of the surface of the fiber member. According to
a fifth aspect of the invention, there is provided a method of producing a fiber member, which
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comprises applying and drying the adhesive treatment solution on at least a part of the surface of a
fiber substrate. According to a sixth aspect of the invention, there is provided a composite member
comprising the fiber member bonded to a vulcanized rubber member. According to a seventh
aspect of the invention, there is provided a method of producing a fiber member/vulcanized rubber
composite member, which comprises bringing a vulcanizing rubber composition into contact with an
adhesive composition layer formed on the surface of a fiber member and then vulcanizing it.
Best Mode for Carrying Out the Invention
[0008] Hereinafter, the present invention is described in more detail.
[0009] The latex of the present invention is a latex of nitrile group-containing copolymer rubber
containing 10 to 30 mass% alpha , beta -ethylenically unsaturated nitrile monomer unit, having an
iodine value of 250 or less and a Mooney viscosity (ML1+4, 100 DEG C) of 10 to 120, and showing a
temperature difference of 25 DEG C or less between extrapolated glass transition initiation
temperature (Tig) and extrapolated glass transition end temperature (Teg) measured by differential
scanning calorimetry.
[0010] The nitrile group-containing copolymer rubber used in the present invention contains 10 to
30 mass% alpha , beta -ethylenically unsaturated nitrile monomer unit, has an iodine value of 250 or
less and a Mooney viscosity (ML1+4, 100 DEG C) of 10 to 120, and shows a temperature difference
of 15 DEG C or less between extrapolated glass transition initiation temperature (Tig) and
extrapolated glass transition end temperature (Teg) measured by differential scanning calorimetry.
[0011] The alpha , beta -ethylenically unsaturated nitrile monomer includes acrylonitrile, alpha halogenoacrylonitrile such as alpha -chloroacrylonitrile and alpha -bromoacrylonitrile, and alpha alkylacrylonitrile such as methacrylonitrile and ethacrylonitrile, among which acrylonitrile is preferable.
[0012] The content of the alpha , beta -ethylenically unsaturated nitrile monomer unit (referred to
hereinafter as monomer unit (a)) in the nitrile group-containing copolymer rubber is 10 to 30 mass%,
preferably 12 to 25 mass%, more preferably 17 to 23 mass%. When the content of the monomer unit
(a) is too low, the resulting adhesive composition is inferior in adhesiveness, while when the content
is too high, the composition is inferior in tackiness.
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[0013] In production of the nitrile group-containing copolymer rubber, a monomer copolymerizable
with the alpha , beta -ethylenically unsaturated nitrile monomer is exemplified by a conjugated diene
monomer, a non-conjugated diene monomer and alpha -olefin. The conjugated diene monomer
includes, for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene etc.,
among which 1,3-butadiene is preferable. The non-conjugated diene monomer is preferably the one
having 5 to 12 carbon atoms, and examples include 1,4-pentadiene, 1,4-hexadiene, vinylnorbornene,
dicyclopentadiene etc. The alpha -olefin is preferably the one having 2 to 12 carbon atoms, and
examples include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene etc. The
monomer unit (a) may also be copolymerized with an aromatic vinyl monomer, a fluorine-containing
vinyl monomer, an alpha , beta -ethylenically unsaturated monocarboxylic acid, an alpha , beta ethylenically unsaturated dicarboxylic acid or an anhydride thereof, a copolymerizable aging inhibitor
etc.
[0014] The aromatic vinyl monomer includes, for example, styrene, alpha -methylstyrene,
vinylpyridine etc. The fluorine-containing vinyl monomer includes, for example, fluoroethyl vinyl ether,
fluoropropyl vinyl ether, o-trifluoromethyl styrene, vinyl pentafluorobenzoate, difluoroethylene,
tetrafluoroethylene etc. The alpha , beta -ethylenically unsaturated monocarboxylic acid includes, for
example, acrylic acid, methacrylic acid etc. The alpha , beta -ethylenically unsaturated dicarboxylic
acid includes, for example, itaconic acid, fumaric acid, maleic acid etc. The alpha , beta ethylenically unsaturated dicarboxylic anhydride includes, for example, itaconic anhydride, maleic
anhydride etc. The copolymerizable aging inhibitor includes, for example, N-(4anilinophenyl)acrylamide, N-(4-anilinophenyl)methacrylamide, N-(4-anilinophenyl)cinnamamide, N(4-anilinophenyl)crotonamide, N-phenyl-4-(3-vinylbenzyloxy)aniline, N-phenyl-4-(4vinylbenzyloxy)aniline etc.
[0015] The iodine value of the nitrile group-containing copolymer rubber of the present invention is
250 or less, preferably 200 or less, more preferably 180 or less. When the iodine value is too high,
the adhesive composition is inferior in heat resistance.
[0016] The Mooney viscosity (ML1+4, 100 DEG C) of the nitrile group-containing copolymer rubber
of the present invention is 100 to 120, preferably 15 to 80, more preferably 20 to 60. When the
Mooney viscosity is too low, the adhesive composition may be inferior in mechanical strength, while
when the Mooney viscosity is too high, the composition may be inferior in tackiness.
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[0017] The temperature difference ( DELTA Tg) between the extrapolated glass transition initiation
temperature (Tig) and extrapolated glass transition end temperature (Teg) of the nitrile groupcontaining copolymer rubber of the present invention, as determined by differential scanning
calorimetry prescribed in JIS K7121 (Method of Measuring Transition Temperature of Plastics), is 15
DEG C or less, preferably 14 DEG C or less, more preferably 13 DEG C or less. When this
temperature difference ( DELTA Tg) is too great, the adhesive composition of the present invention is
inferior in tackiness.
[0018] To allow the temperature difference ( DELTA Tg) between the extrapolated glass transition
initiation temperature (Tig) and the extrapolated glass transition end temperature (Teg) to be in the
above range, the compositional distribution breadth of the monomer unit (a) in the nitrile groupcontaining copolymer rubber and the compositional distribution breadth of the monomer unit
(referred to hereinafter as monomer (b)) copolymerizable with the alpha , beta -ethylenically
unsaturated nitrile monomer is preferably 80 mass% or less, more preferably 70 mass% or less, still
more preferably 55 mass% or less. The compositional distribution breadth of each monomer refers to
the ratio of [difference between the maximum and minimum contents of each monomer in a minute
part of the polymer] to [content of each monomer in the whole polymer]. The minute part of the
polymer refers to a very small part of the polymer, and refers to a part accounting for preferably 1 to
5 mass%, more preferably 2 to 4 mass%, of the molecular weight of the polymer. The compositional
distribution breadth is determined usually based on measurements of a change with time in the
amount of the unreacted monomer in the polymerization reaction. When the compositional
distribution breadth is too broad, the temperature difference ( DELTA Tg) may be too great.
[0019] The structure of the monomer unit may be changed by treatment such as hydrogenation
after the completion of polymerization. In this case, the compositional distribution breadth shall be in
the above range, assuming that the monomer unit before and after change is the same monomer unit.
For example, when butadiene is copolymerized and hydrogenated after the completion of
copolymerization, at least a part of unsaturated bonds of butadiene units are hydrogenated to form
saturated butadiene units. In this case, it is assumed that the saturated butadiene unit is the same as
the butadiene unit, and the compositional distribution breadth of the two kinds of units in total shall
be in the above range.
[0020] When plural kinds of monomers are used as the monomer copolymerizable with the alpha ,
beta -ethylenically unsaturated nitrile monomer, the compositional distribution breadth of the
respective monomers is preferably in the above range. When plural kinds of monomers are used as
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the alpha , beta -ethylenically unsaturated nitrile monomer, the compositional distribution breadth of
the respective monomers is also preferably in the above range.
[0021] The content of the monomer unit (a) or (b) in the nitrile group-containing copolymer rubber
can be determined by a combination of a plurality of measurement methods such as nitrogen content
measurement by a semimicro-Kjeldahl method, measurement of the amount of unsaturated bonds by
analysis of IR absorption spectrum or measurement of iodine value, identification of a partial
structure by analysis of IR absorption spectrum, H-NMR, C-NMR, pyrolysis gas chromatography etc. ,
andmeasurement of amount ratio. Generally, the identification of a partial structure and measurement
of amount ratio by H-NMR are the most reliable, but there is the case where analysis is not feasible
because of overlapping of a plurality of peaks in H-NMR chart, and it is thus desired in analysis to
use H-NMR in combination with other methods.
[0022] In the latex of the present invention, the nitrile group-containing copolymer rubber exists as
particles, and the average diameter of the particles is preferably 50 to 150 mu m, more preferably 70
to 120 mu m, still more preferably 80 to 100 mu m. When the particle diameter is too small, the
particles are easily aggregated, while when the particle diameter is too large, the particles are
precipitated, thus making storage thereof or preparation of the adhesive treatment solution difficult.
[0023] The method of producing the latex according to the present invention is not particularly
limited, but usually emulsion polymerization is used. Polymerization assistants used generally in
emulsion polymerization, such as an emulsifying agent, a polymerization initiator and a molecularweight regulator, may be used. The type and amount of these additives are not particularly limited
insofar as the nitrile group-containing copolymer rubber latex can be obtained.
[0024] When the latex of the present invention is to be produced by emulsion polymerization, the
compositional distribution breadth of the monomer unit is regulated so as to be in the specific range
during polymerization as described above, to polymerize rubber whose extrapolated glass transition
initiation temperature (Tig) and extrapolated glass transition end temperature (Teg) show a
temperature difference ( DELTA Tg) in the above-defined range. The polymerization reaction
conditions for regulating the compositional distribution breadth may be previously determined by a
preliminary experiment. In the preliminary experiment, the amount of each monomer in the
polymerization reaction solution is measured as the polymerization proceeds, preferably every time
the degree of polymerization conversion is increased by 1 to 5 mass%, more preferably every time
the degree of polymerization conversion is increased by 2 to 4 mass%, whereby the content of each
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monomer in a minute part of the polymer is determined. The polymerization reaction conditions are
determined such that the compositional distribution breadth determined on the basis of the content
comes to be in the range described above. Generally, the compositional distribution breadth is
controlled by additionally adding a specific amount of each monomer at a predetermined point in
time. Examination of the polymerization reaction conditions can also be made by computer
simulation etc. , and its result may be confirmed in the experiment.
[0025] To allow the iodine value of the polymerized rubber to be 250 or less, hydrogenation
reaction is necessary. For this reaction, a hydrogenation catalyst may be added in a necessary
amount to an aqueous emulsifying agent solution having the rubber particles dispersed therein,
followed by bringing the rubber particles in the aqueous emulsifying agent solution into contact with
hydrogen. The hydrogenation catalyst is not particularly limited. The hydrogenation catalyst can be
used as a supported catalyst having a catalytic component supported on a carrier and introduced
into a reaction system. The hydrogenation catalyst can also be used as a non-supported catalyst
which without supporting a catalytic component on a carrier, is dissolved or dispersed directly in a
reaction system. Further, the supported and non-supported catalysts can be simultaneously used.
The hydrogenation temperature is preferably 20 to 150 DEG C, more preferably 30 to 100 DEG C.
When the hydrogenation temperature is too low, the reaction rate may be low, while when the
temperature is too high, side reactions such as hydrogenation of nitrile group may occur. A hydrogen
gas is used as the hydrogen source and may be brought into contact with the nitrile groupcontaining unsaturated copolymer rubber in latex form. The hydrogen pressure is preferably
atmospheric pressure to 150 kg/cm, more preferably 5 to 100 kg/cm. When the hydrogen pressure is
too low, the reaction rate may be low, while when the hydrogen pressure is too high, the safety of
facilities etc. may be problematic. After the hydrogenation reaction is finished, the hydrogenation
catalyst is preferably removed, but if its amount is in such a range as not to influence tackiness, the
catalyst may remain. The method of removing the hydrogenation catalyst is not particularly limited,
and for example, the hydrogenation catalyst may be removed by bringing the reaction mixture into
contact with ion-exchange resin to adsorb it onto the resin.
[0026] The solids content of the latex of the present invention is preferably 10 to 60 mass%, more
preferably 20 to 50 mass%, still more preferably 35 to 45 mass%. When the solids content is too low,
a uniform adhesive treatment solution may not be prepared, while when it is too high, the
composition may be inferior in shelf stability.
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[0027] The adhesive treatment solution of the present invention comprises the latex and a
resorcinol/formaldehyde resin. The adhesive treatment solution is the one wherein the components in
the adhesive composition for bonding a pair of substrates to each other in a composite material are
dispersed in an aqueous medium.
[0028] The resorcinol/formaldehyde resin used in the present invention is a resin obtained by
reacting resorcinol with formaldehyde. It may be a novolak type or resol type, and the amount of
formaldehyde reacting with 1 mole of resorcinol is preferably 0.1 to 3.5 moles, more preferably 0.2 to
3 moles. The reaction method is not particularly limited, and the reaction may be carried out by a
known method.
[0029] The amount of the resorcinol/formaldehyde resin blended with 100 parts by weight of the
nitrile group-containing copolymer rubber particles dispersed in the latex is preferably 3 to 60 parts
by weight, more preferably 5 to 40 parts by weight, still more preferably 10 to 30 parts by weight.
When the amount of the resorcinol/formaldehyde resin blended is too low, the adhesive composition
may be poor in adhesiveness, while when the amount is too high, the adhesive composition may be
poor in tackiness.
[0030] The adhesive composition of the present invention comprises a resorcinol/formaldehyde
resin and nitrile group-containing copolymer rubber particles containing 10 to 30 mass% alpha ,
beta -ethylenically unsaturated nitrile monomer unit, having an iodine value of 250 or less and a
Mooney viscosity of 10 to 120, and showing a temperature difference of 15 DEG C or less between
extrapolated glass transition initiation temperature (Tig) and extrapolated glass transition end
temperature (Teg) measured by differential scanning calorimetry.
[0031] The type of the nitrile group-containing copolymer rubber particles and the
resorcinol/formaldehyde resin and the ratio of the two are the same as in the latex and the adhesive
treatment solution described above.
[0032] The water content in the adhesive composition is preferably 1 mass% or less, more
preferably 0.5 mass% or less, more preferably 0.1 mass% or less. When the water content is too high,
the adhesiveness and tackiness may be lowered. After adhesion, the water may cause foaming and
release of the adhesive-bonded substrate.
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[0033] The method of producing the adhesive composition is not particularly limited, but generally
the adhesive composition is produced by removing water from the adhesive treatment solution:
specifically, a coating film formed by applying the adhesive treatment solution onto the surface of at
least one of a pair of substrates intended to be adhesive-bonded and then drying the solution is used
as an adhesive composition layer. The coating method is not particularly limited, and may be carried
out by brushing, spraying or dipping. The method of drying water is not particularly limited, and the
adhesive treatment solution may be treated by a combination of reduced pressure and heating.
[0034] The thickness of the adhesive composition layer is not particularly limited. For example,
when the adhesive composition is applied to a glass fiber strand of about 0.1 mm in thickness, the
thickness of the composition after drying is preferably 0.1 to 10 mu m, more preferably 0.2 to 5 mu
m, still more preferably 0.5 to 2 mu m. A too thick layer is not preferable because the strength of a
glass fiber cord obtained by twisting the strands is adversely influenced. On the other hand, when
the adhesive composition layer is to be formed by a method of spraying or dipping a woven or
nonwoven fabric, the thickness of the composition after drying is preferably 0.1 to 100 mu m, more
preferably 0.5 to 100 mu m, still more preferably 1 to 50 mu m.
[0035] Preferable examples of one substrate out of a pair of substrates to be adhesive-bonded to
each other include fiber substrates, and reinforcing fiber substrates such as a nonwoven fabric
formed from fibers, a thread having fibers twisted therein, a fabric having such threads woven therein,
and a cord having fibers twisted therein are preferable. Preferable fibers include glass fiber,
polyester fiber, polyamide fiber, polybenzobisoxazole fiber etc.
[0036] The fiber member of the present invention has a layer of the adhesive composition formed
on at least a part of the surface of a fiber substrate. When the fiber substrate is a thread or cord, the
adhesive composition layer may be formed on the surface of a thread or cord obtained by twisting
fibers to form the fiber member, or a fiber or a strand of bundled fibers may be coated thereon with
the adhesive treatment solution to form a layer of the adhesive composition and then twisted to give a
thread or cord used as the fiber member. A woven fabric using the threads obtained in this manner
may be used as the fiber member.
[0037] Particularly in the fiber member made of a thread or cord produced by twisting fibers having
the adhesive composition layer formed thereon, the twisted fibers are hardly frayed, and even if the
fibers in the twisted thread or cord are partially cut, such cutting hardly causes fray. This is
preferable in that the strength of the fiber member can be maintained by preventing fray.
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[0038] The surface of the formed layer of the adhesive composition is excellent in adhesion to a
vulcanized rubber member. In particular, the adhesive composition layer while being into contact
with a vulcanizable rubber composition is vulcanized, whereby the fiber member and the vulcanized
rubber member can be strongly bonded to each other.
[0039] The method of producing the fiber member is not particularly limited, but a method that
involves applying the adhesive treatment solution onto at least a part of the surface of a fiber member
and then drying it is generally used.
[0040] Preferable examples of the other substrate out of a pair of substrates intended to be
adhesive-bonded include vulcanized rubber members such as belt, tire and hose. Non-vulcanized
rubber serving as the starting material thereof is not particularly limited, but preferable rubber
includes nitrile group-containing copolymer rubber, and particularly preferable rubber includes nitrile
group-containing copolymer rubber having an iodine value of 100 or less. The non-vulcani zed
rubber may be compounded if necessary with general additives such as reinforcing materials such
as silica, carbon etc. , fillers such as talc, clay etc., stabilizers such as an antioxidant, a weathering
agent etc., and pigments. By compounding the non-vulcanized rubber with a vulcanizing agent
suitable for the characteristics of the rubber, a vulcanizable rubber composition is prepared and then
vulcanized to give a vulcanized rubber member. In the case of the nitrile group-containing copolymer
rubber, sulfur, a sulfur-based vulcanizing agent such as morpholine disulfide, or an organic peroxide
vulcanizing agent is generally used.
[0041] The composite member of the present invention comprises a fiber member adhesivebonded to a vulcanized rubber member. The method of producing the composite member is not
particularly limited, but a method that involves bringing an adhesive composition layer formed on the
surface of a fiber member into contact with a vulcanizable rubber composition and then vulcanizing
the vulcanizable rubber composition is preferably used. According to this method, a composite
member having the fiber member bonded strongly to the vulcanized rubber member can be
obtained.
[0042] The method of bringing the adhesive composition layer formed on the surface of a fiber
member into contact with a vulcanizable rubber composition is not particularly limited. Depending on
the object, a two-layer structure of the fiber member and the vulcanizable rubber composition may
be formed, or the fiber member may be buried in the vulcanizable rubber composition. Molding and
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vulcanization may besimultaneously conducted; molding may be followed by vulcanization; or after
vulcanization, the composite member may be cut and molded. For example, the fiber member and
the vulcanizable rubber composition can be fixed respectively in predetermined positions in a mold,
whereby the adhesive composition layer is brought into contact with the vulcanizable rubber
composition, and the mold can be heated to effect molding and vulcanization simultaneously.
Alternatively, the fiber member may be laminated on the vulcanizable rubber composition in plate
form previously subjected to extrusion molding, whereby the layer of the adhesive composition is
brought into contact with the vulcanizable rubber composition, followed by vulcanization by heating.
Examples
[0043] Hereinafter, the present invention is described in more detail by reference to the Examples.
Unless otherwise specified, "parts" refer to parts by weight.
[0044] The content of each monomer unit in the nitrile group-containing copolymer rubber is a
value determined on the basis of H-NMR, iodine content measurement, and nitrogen content
measurement by the semimicro-Kjeldahl method. It was confirmed that this value does not contradict
a difference between the amount of the monomer used in polymerization and the amount of the
remaining monomer.
[0045] The extrapolated glass transition initiation temperature (Tig) and extrapolated glass
transition end temperature (Teg)were measured by heatreflux differential scanning calorimetry
according to JIS K7121. However, the rate of heating was changed from 20 DEG C/min. to 10 DEG
C/min. in measurement in order to measurement accuracy.
[0046] The iodine value and Mooney viscosity (ML1+4, 100 DEG C) were measured according to
JIS K 6235 and JIS K 6300, respectively.
[0047] The adhesion of a glass fiber cord to a vulcanized rubber was measured by a method
described later according to JIS K 3256.
[0048] The tackiness between glass and the adhesive composition was measured by using a TelTack meter (model TT-1 manufactured by Monsanto, JP-B 47-12830) Reference Example 1
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[0049] Palladium nitrate (manufactured by NE Chemcat Corporation) was dissolved at a palladium
concentration of 10 mass% in distilled water to prepare 100 ml aqueous solution of palladium nitrate.
While the pH of this aqueous solution was monitored, the pH was adjusted to 12 by adding sodium
hydroxide (solid). 20 ml of this aqueous basic solution was mixed with 1L separately prepared carrier
slurry (carrier:magnesium silicate manufactured by Tomita Pharmaceutical Co., Ltd.; the amount of
the carrier in the slurry: 100 g). The pH of the slurry after being mixed was 12. The mixture was
stirred for 30 minutes, and then solids were separated by filtration and washed sufficiently with
distilled water. The recovered solids were vacuum-dried at 60 DEG C for 20 hours to give a
supported catalyst. The amount of palladium supported thereon, as determined by the atomicabsorption method, was 2 mass%.
Example 1
[0050] A reactor was charged with an emulsifying agent consisting of 205 parts of deionized water
and 3 parts of sodium dodecyl sulfate (emulsifying agent), and then 11 parts of acrylonitrile, 89 parts
of 1,3-butadiene, 0.54 part of t-dodecyl mercaptan (molecular-weight regulator), 0.015 part of ferrous
sulfate (activator) and 0.043 part of p-menthane hydroperoxide (polymerization initiator) were added
thereto, and while the degree of polymerization conversion was measured, the emulsion
polymerization of the mixture was initiated at 10 DEG C. When the degree of polymerization
conversion reached 26%, 4.3 parts of acrylonitrile were added. When the degree of polymerization
conversion reached 41% upon adding the added acrylonitrile to a criterion for calculating the degree
of polymerization conversion, 4.3 parts of acrylonitrile were further added. When the degree of
polymerization conversion reached 59% upon adding this additionally added acrylonitrile to a
criterion for calculating the degree of polymerization conversion, 4.3 parts of acrylonitrile were added
again. When the degree of polymerization conversion reached 80% upon adding this additionally
added acrylonitrile to a criterion for calculating the degree of polymerization conversion, 0.129 part of
hydroxylamine sulfate was added to terminate the polymerization. During the polymerization, a very
small amount of the polymerization reaction solution was collected and analyzed every time the
degree of polymerization conversion was increased by 3%, and the content of each monomer in a
minute part of the polymer was determined. The results are shown in Table 1. Following termination
of the polymerization, the reaction solution was heated, and the unreacted monomer was recovered
by steam distillation at 70 DEG C under reduced pressure, and then 2 parts of 2,6-di-tert-butyl-4-
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methyl phenol (aging inhibitor) were added to the reaction mixture, whereby a nitrile groupcontaining copolymer rubber latex was obtained. The content of acrylonitrile in the nitrile groupcontaining copolymer rubber contained in this latex was 22.5%, the iodine value was about 364, the
Mooney viscosity (ML1+4, 100 DEG C) was 30, and DELTA Tg was 13 DEG C.
[0051] The hydrogenation catalyst obtained in Reference Example 1 was added to the nitrile
group-containing copolymer rubber latex such that the amount of the palladium became 1600 ppm,
and the latex was hydrogenated at 50 DEG C by blowing a hydrogen gas at a hydrogen pressure of
5 MPa until the iodine value reached 160, to give a hydrogenated nitrile group-containing copolymer
rubber latex. The content of acrylonitrile in the nitrile group-containing copolymer rubber contained in
this latex was 22.5%, the Mooney viscosity (ML1+4, 100 DEG C) was 30, and DELTA Tg was 13
DEG C.
[0052] To the resulting hydrogenated nitrile group-containing copolymer rubber latex was added a
resorcinol/formaldehyde resin (reaction product of 1 mol resorcinol and 1 mol formaldehyde,
manufactured by Wako Pure Chemical Industries) in an amount of 20 parts relative to 100 parts of the
rubber particles, and the mixture was stirred slowly until it became uniform, whereby an adhesive
treatment solution was prepared.
[0053] This adhesive treatment solution was applied onto each of glass fiber strands (filament
diameter, 9 mu m; 101 Tex (number of filaments, 600)) having a non-alkali glass composition (SiO2,
64.4%; Al2O3, 25%; CaO, 0.3%; MgO 10.0%; B2O3, 0.1%; Na2O and K2O in total, 0.2%) such that
the thickness of the adhesive composition layer became about 1.5 mu m, and the strands were heattreated at 280 DEG C for 1 minute and then subjected to preliminary twisting 2.1 times per inch, and
11 strands were combined and subjected to final twisting 2.1 times per inch in the opposite direction
to the preliminary twisting, to give a glass fiber cord.
[0054] 60 parts of carbon black N550, 5 parts of zinc white No. 1, 1 part of stearic acid, 10 parts of
trioctyl trimellitate, 1.5 parts of 4,4-( alpha , alpha -dimethylbenzyl)diphenylamine, 1.5 parts of
mercaptobenzothiazole zinc salt, 1.5 parts of tetramethyl thiuram disulfide, 0.5 part of sulfur and 1
part of cyclohexyl benzothiazyl sulfonamide were incorporated into 100 parts of hydrogenated
acrylonitrile/butadiene copolymer rubber (Zet Pole 2020 manufactured by Nippon Zeon Co., Ltd.;
acrylonitrile unit content, 36.2%; iodine value 28; Mooney viscosity (ML1+4, 100 DEG C) 78), to
prepare a vulcanizable rubber composition. This vulcanizable rubber composition was molded into a
sheet of 5 mm in thickness by a press pressure of 5 MPa.
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[0055] The above glass fiber cords were arranged in a size of 12 cm in length and 25 mm in width
on the sheet molding of the vulcanizable rubber composition and then vulcanized at 150 DEG C for
30 minutes at a press pressure of 5 MPa to give an adhesion test specimen. The resulting test
specimen was measured for the initial adhesion between the glass fiber cord and the vulcanized
rubber in a peel test according to JIS K 6256. The content of the glass fiber cord in the test specimen
was about 30 mass%.
[0056] The resulting adhesive treatment solution was used to measure the tackiness between glass
and the adhesive composition. The results are shown in Table 1.
Comparative Example 1
[0057] A nitrile group-containing copolymer rubber latex was obtained by polymerization in the
same manner as in Example 1 except that upon initiation of polymerization, the amount of acrylonitrile
was changed from 11 parts to 20 parts, the amount of 1,3-butadiene was changed from 89 parts to
80 parts, and during the polymerization, no additional acrylonitrile was added. The content of
acrylonitrile in the nitrile group-containing copolymer rubber contained in this latex was 22.9%, the
iodine value was about 360, the Mooney viscosity (ML1+4, 100 DEG C) was 30, and DELTA Tg was
44 DEG C. This latex was hydrogenated in the same manner as in Example 1 to give hydrogenated
nitrile group-containing copolymer rubber latex. The content of acrylonitrile in the hydrogenated
nitrile group-containing copolymer rubber contained in this latex was 22.9%, the iodine value was
about 160, the Mooney viscosity (ML1+4, 100 DEG C) was 30, and DELTA Tg was 42 DEG C. Using
this hydrogenated nitrile group-containing copolymer rubber latex, an adhesive treatment solution
and an adhesion test specimen were obtained in the same manner as in Example 1, and the initial
adhesion between the glass fiber cord and the vulcanized rubber and the tackiness between glass
and the adhesive composition were measured. The results are shown in Table 1.
Comparative Example 2
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[0058] A nitrile group-containing copolymer rubber latex was obtained by polymerization in the
same manner as in Example 1 except that the amount of t-dodecylmercaptan was changed from
0.54 part to 0.05 part. The content of acrylonitrile in the nitrile group-containing copolymer rubber
contained in this latex was 22.5%, the iodine value was about 364, the Mooney viscosity (ML1+4, 100
DEG C) was 155, and DELTA Tg was 13 DEG C. This latex was hydrogenated in the same manner
as in Example 1 to give hydrogenated nitrile group-containing copolymer rubber latex. The content of
acrylonitrile in the hydrogenated nitrile group-containing copolymer rubber contained in this latex
was 22.5, the iodine value was 160, the Mooney viscosity (ML1+4, 100 DEG C) was 150, and DELTA
Tg was 13 DEG C. Using this hydrogenated nitrile group-containing copolymer rubber latex, an
adhesive treatment solution and an adhesion test specimen were obtained in the same manner as in
Example 1, and the initial adhesion between the glass fiber cord and the vulcanized rubber and the
tackiness between glass and the adhesive composition were measured. The results are shown in
Table 1.
Comparative Example 3
[0059] The same treatment as in Example 1 was carried out except that the nitrile group-containing
copolymer rubber latex before hydrogenation was used in place of the hydrogenated nitrile groupcontaining copolymer rubber latex. The results are shown in Table 1. The content of acrylonitrile in
the nitrile group-containing copolymer rubber contained in this latex was 22.5%, the iodine value was
about 364, the Mooney viscosity (ML1+4, 100 DEG C) was 30, and DELTA Tg was 13 DEG C.
Id=Table 1 Columns=5
Head Col 1:
Head Col 2: Example
Head Col 3 to 5: Comparative Example
SubHead Col 1:
SubHead Col 2: 1
SubHead Col 3: 1
SubHead Col 4: 2
SubHead Col 5: 3
Nitrile group-containing copolymer rubber
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Acrylonitrile unit (a)
Content (mass%)22.522.922.522.5
Maximum content in minute part (mass%)27.933.627.927.9
Minimum content in minute part (mass%)17.49.617.417.4
Compositional distribution breadth (mass%)471054747
Butadiene unit (b) (before hydrogenation)
Content (mass%)77.577.177.577.5
Maximum content in minute part (mass%)82.690.482.682.6
Minimum content in minute part (mass%)72.166.472.172.1
Compositional distribution breadth (mass%)13311313
Extrapolated glass transition initiation temperature (Tig) ( DEG C)-53-70-53-53
Extrapolated glass transition end temperature (Teg) ( DEG C)-40-28-40-40
Difference (Tg DELTA ) between Tig and Teg ( DEG C)13421313
Mooney viscosity303015030
Iodine value160160160400
Tackiness between glass and adhesive composition (x 10 Pa)6.783.342.224.47
Adhesion between glass fiber cord and vulcanized rubber (x10 N/m)8.667.878.279.45
[0060] Composite members prepared by using adhesive treatment solutions whose nitrilecontaining copolymer rubber latex had a too large difference between extrapolated glass transition
initiation temperature (Tig) and extrapolated glass transition end temperature (Teg) (Comparative
Example 1), too high Mooney viscosity (Comparative Example 2) or too high iodine value
(Comparative Example 3) were inferior in tackiness between the fiber member and the adhesive
composition layer.
[0061] On the other hand, when the latex of the present invention was used, the composite
member was excellent not only in adhesion between the glass fiber cord and the vulcanized rubber
but also in tackiness.
Industrial Applicability
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[0062] The adhesive composition of the present invention is excellent not only in adhesion to nitrile
group-containing copolymer rubber having a low iodine value but also in tackiness. Because of
excellent tackiness, the adhesive composition can bundle fibers strongly and prevents the
deterioration of a reinforcing fiber substrate caused by fraying and cutting of fibers. Accordingly, the
adhesive composition of the present invention can be used in production of fiber-reinforced belts,
tires and hoses.Claims:
1. A latex of nitrile group-containing copolymer rubber containing 10 to 30 mass% alpha , beta ethylenically unsaturated nitrile monomer unit, having an iodine value of 250 or less and a Mooney
viscosity (ML1+4, 100 DEG C) of 10 to 120, and showing a temperature difference ( DELTA Tg) of 15
DEG C or less between extrapolated glass transition initiation temperature (Tig) and extrapolated
glass transition end temperature (Teg) measured by differential scanning calorimetry.
2. The latex according to claim 1, wherein the temperature difference ( DELTA Tg) is 14 DEG C or
less.
3. The latex according to claim 1 or 2, wherein the compositional distribution breadth of each
monomer unit in the nitrile group-containing copolymer rubber is 80 mass% or less wherein the
compositional distribution breadth of each monomer is the ratio of a difference between the
maximum and minimum contents of each monomer in a minute part of the polymer to the content of
each monomer in the whole polymer.
4. The latex according to any one of claims 1 to 3,
wherein the compositional distribution breadth of a monomer unit copolymerizable with the alpha ,
beta -ethylenically unsaturated nitrile monomer is 80 mass% or less wherein the compositional
distribution breadth of each monomer is the ratio of a difference between the maximum and minimum
contents of each monomer in a minute part of the polymer to the content of each monomer in the
whole polymer.
5. The latex according to any one of claims 1 to 4, wherein the content of the alpha , beta ethylenically unsaturated nitrile monomer unit in the nitrile group-containing copolymer rubber is 12
to 25 mass%.
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6. The latex according to any one of claims 1 to 5, wherein the iodine value of the nitrile groupcontaining copolymer rubber is 200 or less.
7. The latex according to any one of claims 1 to 6, wherein the average particle diameter of the nitrile
group-containing copolymer rubber is 50 to 150 mu m.
8. An adhesive treatment solution comprising the latex according to any one of claims 1 to 7 and a
resorcinol/formaldehyde resin.
9. The treatment solution according to claim 8, wherein the amount of the resorcinol/formaldehyde
resin incorporated into 100 parts by weight of the nitrile group-containing copolymer rubber
dispersed in the latex is 3 to 60 parts by weight.
10. An adhesive composition comprising a resorcinol/formaldehyde resin and nitrile group-containing
copolymer rubber particles containing 10 to 30 mass% alpha , beta -ethylenically unsaturated nitrile
monomer unit, having an iodine value of 250 or less and a Mooney viscosity (ML1+4, 100 DEG C) of
10 to 120, and showing a temperature difference ( DELTA Tg) of 15 DEG C or less between
extrapolated glass transition initiation temperature (Tig) and extrapolated glass transition end
temperature (Teg) measured by differential scanning calorimetry.
11. The adhesive composition according to claim 10, wherein the amount of the
resorcinol/formaldehyde resin incorporated into 100 parts by weight of the nitrile group-containing
copolymer rubber particles is 3 to 60 parts by weight.
12. The adhesive composition according to claim 10 or 11, wherein the water content in the
composition is 1 mass% or less.
13. A fiber member comprising a layer of the adhesive composition according to any one of claims
10 to 12 formed on at least a part of the surface of a fiber member.
14. The fiber member according to claim 13, wherein the thickness of the adhesive composition layer
after drying is 0.1 to 10 mu m.
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15. The fiber member according to claim 13 or 14, wherein the fiber constituting the fiber substrate is
selected from the group consisting of glass fiber, polyester fiber, polyamide fiber and
polybenzobisoxazole.
16. A method of producing a fiber member, which comprises applying and drying the adhesive
treatment solution according to claim 8 or 9 on at least a part of the surface of a fiber substrate.
17. A composite member comprising the fiber member according to any one of claims 13 to 15
adhesive-bonded to a vulcanized rubber member.
18. A method of producing a fiber member/vulcanized rubber composite member, which comprises
bringing a vulcanizable rubber composition into contact with an adhesive composition layer formed
on the surface of the fiber member according to any one of claims 13 to 15 and then vulcanizing it.
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35. WO2004050320 - 17.06.2004
EXTRUSION PULVERIZATION PROCESS OF A VULCANIZED RUBBER MATERIAL
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO2004050320
Inventor(s):
TIRELLI DIEGO [IT] (--); GALBUSERA MICHELE [IT] (--); PERUZZOTTI FRANCO [IT]
(--); PUPPI CRISTIANO [IT] (--); TESTI STEFANO [IT] (--); MONTEROSSO ANTONIO [IT] (--); DI
BIASE MATTEO [IT] (--)
Applicant(s): PIRELLI and C SPA [IT] (--); TIRELLI DIEGO [IT] (--); GALBUSERA MICHELE [IT] (-); PERUZZOTTI FRANCO [IT] (--); PUPPI CRISTIANO [IT] (--); TESTI STEFANO [IT] (--);
MONTEROSSO ANTONIO [IT] (--); DI BIASE MATTEO [IT] (--)
IP Class 4 Digits: B29B
IP Class:
B29B17/00; B29B13/10
Application Number:
WO2002EP13614 (20021202)
Priority Number: WO2002EP13614 (20021202)
Family: WO2004050320
Equivalent:
WO2004050321
Cited Document(s):
DE4009902; EP1201389; US5704555; GB871923; GB1334718;
US2412586; US4041115
Abstract:
THE PRESENT INVENTION RELATES TO A PROCESS FOR PRODUCING A RUBBER POWDER
FROM A VULCANIZED RUBBER MATERIAL. THE PROCESS COMPRISES THE STEPS OF: A)
FEEDING AN EXTRUDER WITH THE VULCANIZED RUBBER MATERIAL, THE EXTRUDER
COMPRISING A BARREL AND AT LEAST ONE SCREW ROTATABLY MOUNTED INTO SAID BARREL;
B) CONTACTING THE VULCANIZED RUBBER MATERIAL WITH THE COOLANT; C) OPERATING
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THE EXTRUDER SO AS TO GRIND THE VULCANIZED RUBBER MATERIAL TO FORM A RUBBER
POWDER, AND D) DISCHARGING THE RUBBER POWDER FROM THE EXTRUDER. PREFERABLY,
THE PROCESS COMPRISES THE STEP OF INTRODUCING INTO THE EXTRUDER A GRINDING AID
ADDITIVE.Description:
EXTRUSION PULVERIZATION PROCESS OF A VULCANIZED RUBBER MATERIAL
The present invention relates to a process for producing a rubber powder from a vulcanized rubber
material.
In particular, the present invention relates to a process for pulverizing a vulcanized rubber material
by using an extruder.
More in particular, the present invention relates to a process for pulverizing a vulcanized rubber
material comprising a discarded rubber material.
Even more in particular, the present invention relates to a process for pulverizing a vulcanized
rubber material comprising a discarded rubber material including discarded tyres previously torn to
shreds.
The increased production of industrial rubber products has resulted in the accumulation of large
amounts of rubber wastes which per se do not find any practical applications and are generally
disposed in dedicated landfills with the main drawbacks of environment pollution as well as of the
need for large dedicated areas for storing said wastes.
Therefore, the reclaiming of vulcanized rubber material into a product, which can be advantageously
reused, is a widely discussed issue and a long-felt problem to be solved.
Used vulcanized rubber material, such as waste rubber, old tyres and industrial rubber products,
can be comminuted and added to rubber mixtures to be employed in a plurality of applications. This
is particularly advantageous since important amounts of used vulcanized rubber material can be
reused and, moreover, corresponding remarkable amounts of raw materials can be saved by
replacing them with said discarded material.
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The use in a rubber composition of a comminuted vulcanized rubber, whose particle size generally
does not exceed 500 m, does not remarkably impair the quality of the final product.
However, according to the known technologies available on the market, fine powders can be
obtained from rubber material at the expense of large amounts of energy.
Reclaiming processes of used rubber material which are currently employed include: chemical
reclaiming processes such as pyrolysis and devulcanization; thermal reclaiming processes such as
extrusion, injection moulding and pressure moulding; mechanical reclaiming processes such as
granulation, densification, agglomeration and pulverization.
Document US-4,090, 670 discloses the recovery of rubber from scrap vulcanized rubber tyres by
devulcanization of the rubber tyres and subsequent removal of the devulcanized material, e. g. by
rasping.
The devulcanization is obtained by raising the surface temperature of the vulcanized rubber material.
Document US-4,968, 463 discloses the reclamation of thermoplastic material including the steps of:
shredding to about one hundred millimiters, grinding to under about 40 millimeters, drying, preheating from 80 C to 160 C, kneading at 120 C to 250 C and injection moulding or extruding.
A method of pulverizing natural or synthetic rubber materials is known, for instance, from document
US- 3,190, 565 which discloses the comminution thereof in mills provided with knife blades in the
presence of antiagglomerating agents (in the form of polyolefin fines) that inhibit the sticking of the
comminuted material to the cutting blades.
A further method of making powders from industrial
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rubbers consists in comminuting thereof by means of shear forces. For instance, document GB1,424, 768 discloses a plunger-type device provided with a rotating member so that the rubber
material is crushed in the minimal gap between the rotating member and the inside wall of said
device.
A further method of producing finely dispersed powders from used rubber materials is the cryogenic
destruction (e. g. Chemical Technology, Cryopulverizing, T. Nazy, R. Davis, 1976,6, N 3, pages 200203).
According to said method the rubber material is cooled to very low temperatures by using liquid
nitrogen or solid carbon dioxide and then subjecting the cooled material to impact or cutting. This
method produces finely dispersed powders having particle dimensions less than 500 ssm, but it is
very expensive due to the presence of a plant dedicated to liquid nitrogen production.
A further method of making powders from rubber materials consists in using an extrusion device of
the single-screw or multiple-screw type.
For instance, document US-4,607, 797 discloses the pulverization of used polymers in an extrusion
apparatus wherein the used material is heated to above its melting temperature in a first zone of said
extrusion apparatus and cooled to below its solidification temperature with simultaneous precrushing and pulverizing of the solidified material in a second zone of said apparatus to form a
powdered material. The action of the screw of the extruder is used to convey the material through the
barrel of the extruder, while pulverizing disks mounted on the screw in the second cooling zone
perform the pre- crushing and pulverizing of said material.
Document US-5,743, 471 discloses an extruder for solid state shear extrusion pulverization of
polymeric materials comprising a feed zone, a heating zone adjacent
to the feed zone, a powder formation zone adjacent to the heating zone and a powder discharge
zone adjacent to the powder formation zone. Furthermore, the extruder is provided with temperature
adjustment means for heating the polymeric material to a temperature lower than the decomposition
temperature of the polymeric material in the heating zone and for maintaining the polymeric material
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below its melting point in the powder formation zone, but at a temperature above its glass transition
temperature in the powder formation zone to inhibit the formation of agglomerates.
Documents US-4,607, 796; US-5,395, 055; US-5,704, 555 and JP 6-179215 disclose further
processes according to which the extruder is provided with heating and cooling zones.
The Applicant has perceived that, in processes for producing powders from vulcanized rubber
materials by using an extrusion device, the control of the temperature is essential to obtain high
grinding yields in fine particles which do not negatively affect the mechanical properties-e. g. tensile
strength, elongation at break, abrasion resistance-of the rubber compositions they are added to.
In particular, in order to increase the grinding yield in fine particles, the Applicant has perceived that
the rubber material advancing into the barrel of the extrusion device has to be cooled so that during
the grinding step, which is carried out by the extruder screw, the rubber particles do not stick and
agglomerate.
Furthermore, the Applicant has perceived that a suitable control of the rubber material temperature, i.
e. a decrease thereof during the grinding step, is particularly advantageous also in terms of energy
to be transferred to the rubber material for the grinding thereof. In more details, the Applicant has
perceived
that, by controlling the temperature of the rubber material, the mechanical energy which is supplied
during the process can be used to give rise to shear stresses on the rubber particles so that an
efficient grinding thereof is achieved. This means that said energy is not spent for carrying out the
softening or melting of the rubber material and the devulcanizing thereof, but results in obtaining high
grinding yields in very fine particles of the rubber material.
Furthermore, the Applicant has perceived that, in order to perform a very efficient cooling of the
rubber material, it is not sufficient to provide the extruder barrel walls with a cooling circuit which can
remove a predetermined heat amount from the rubber material by contacting the latter with the
cooled barrel walls. In particular, the Applicant has perceived that part of the heat produced during
the grinding step has to be removed by directly acting on the rubber material, i. e. by carrying out a
cooling of the latter from the inside thereof.
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The Applicant has further found that it is possible to efficiently cool the rubber material, during its
advancing along the extruder, by contacting the rubber material with a coolant.
In more details, the Applicant has found that, by introducing at least a predetermined amount of a
coolant into the extruder barrel so as to contact the rubber material during the advancing thereof,
said coolant dissipates a part of the heat produced during the grinding step and thus efficiently cools
the rubber material while being grinded.
The present invention relates to an extrusion process for pulverizing a vulcanized rubber material to
fine particles.
In particular, the present invention relates to a
process for producing a rubber powder from a vulcanized rubber material comprising the steps of:
feeding an extruder with said vulcanized rubber material, said extruder comprising a barrel and at
least one screw rotatably mounted into said barrel; 'contacting said vulcanized rubber material with
at least one coolant; operating the extruder so as to grind said vulcanized rubber material to form
said rubber powder, and discharging said rubber powder from said extruder.
Preferably, the step of operating the extruder comprises at least one step of conveying the
vulcanized rubber material along the extruder and at least one step of grinding the vulcanized rubber
material within the extruder.
Preferably, the step of contacting the rubber is carried out by introducing the coolant into the
extruder barrel, said introduction being performed during at least one step of conveying the
vulcanized rubber material along the extruder.
More preferably, the step of introducing the coolant into the extruder barrel is performed in
association with at least one step of grinding the vulcanized rubber material within the extruder. More
specifically, the step of introducing is performed during the step of grinding; alternatively, the step of
introducing can be performed before the step of grinding, or both.
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According to the invention, when the coolant introduced into the extruder contacts the rubber
material during the grinding thereof, the coolant is able to remove the heat, or at least part of it, at the
very
beginning of its production so that a more efficient and effective control of the rubber material
temperature can be performed with respect to the case in which a single external cooling, i. e. a
cooling carried out by means of a cooling circuit provided within the extruder barrel walls, is
performed.
Preferably, the coolant is a liquid which at least partially evaporates so that at least part of the heat,
which is produced during the grinding action of the extruder screw on the rubber material, is
dissipated.
Preferably, the coolant is a non-cryogenic coolant.
Preferably, the coolant is water.
The process of the present invention is suitable for pulverizing any vulcanized rubber materials such
as synthetic or natural polymers, copolymers, homopolymers, natural or synthetic rubber and
mixtures thereof.
Preferably, the process of the present invention is suitable for pulverizing the vulcanized rubber
material deriving from discarded tyres. In case a discarded tyre is used, the latter is previously torn
to shreds and successively said shreds undergo dedicated working operations in order to remove
steel (e. g. magnetic separation) and textile material (e. g. pneumatic separation) therefrom.
Generally, the extruder is provided with at least one feeding inlet for the introduction thereinto of the
rubber material previously reduced into shreds.
Preferably, the extruder is provided with a main feeding hopper which is located in correspondence
of a first portion of the extruder screw.
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According to an embodiment of the present invention, the rubber material reduced into shreds is
introduced into the extruder barrel by means of said main feeding hopper.
Preferably, the extruder is further provided with at
least one further feeding inlet, which is located in correspondence of a further portion of the extruder
screw, at a predetermined distance from said main feeding hopper.
According to a further embodiment of the present invention, part of the rubber material reduced into
shreds is introduced into the extruder barrel by means of said at least one further feeding inlet.
According to said embodiment, said at least one further feeding inlet is a lateral feeding inlet.
Preferably, the rubber material is continuously introduced into the extruder.
According to a preferred embodiment of the present invention, the coolant is fed to the extruder
through said at least one further feeding inlet. Preferably, said at least one further feeding inlet is an
injection point of the coolant to be introduced into the extruder.
Alternatively, the coolant is fed to the extruder through said at least one lateral feeding inlet.
According to a further embodiment, the coolant and the rubber material can be introduced together
into said at least one lateral feeding inlet.
Alternatively, the coolant is fed to the extruder through the main feeding hopper.
Generally, the extruder screw comprises a plurality of conveying elements and kneading elements
which are assembled according to a predetermined sequence, the latter depending on the kind of
material to be grinded as well as on the grinding yield to be achieved. In more details, the conveying
elements have the function of moving the rubber material along the extruder barrel while the
kneading elements have the function of grinding the rubber material, i. e. of transferring to the rubber
material the mechanical energy necessary for carrying out the desired particle size reduction.
Furthermore, the
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kneading elements have the function of mixing the coolant with the rubber material.
According to an embodiment of the present invention, the coolant is preferably fed to the extruder
through a further feeding inlet positioned in correspondence of at least one kneading element. More
preferably, said further feeding inlet is an injection point.
According to a further embodiment of the present invention, the coolant is fed to the extruder
through a further feeding inlet positioned in correspondence of a conveying element which is located
immediately upstream of a kneading element. This solution is particularly preferred since the
kneading element can be suitably cooled.
Therefore, the introduction of the coolant in correspondence of at least one kneading element or
immediately upstream thereof is a very advantageous configuration since the coolant is directly
introduced into the extruder zones where the grinding step is performed and a heat amount is
inevitably produced.
Furthermore, according to the present invention, it is also possible to selectively cool down only the
kneading elements which, following to their position along the longitudinal extension of the screw as
well as to the specific rubber material to be pulverized, transfer to the rubber material the highest
mechanical shears and are the most effective in the grinding action thereof.
Preferably, the coolant is introduced into the extruder barrel by injection through said at least one
injection point.
Alternatively, the coolant is introduced into the extruder by dripping. In that case, the coolant is fed
to the barrel by means of the main feeding hopper and/or of at least one lateral feeding inlet.
Alternatively, the rubber material introduced into the extruder in the form of shreds of a
predetermined granulometry is previously wet or impregnated with the coolant. This means that the
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step of contacting the vulcanized rubber material with the coolant occurs before the introduction of
the rubber material into the extruder.
Preferably, the coolant is continuously fed to the extruder.
Preferably, the coolant introduced into the extruder is water. More preferably, said coolant is water at
a temperature not greater than 30 C, even more preferably comprised between 5 C and 20 C.
The use of the water as a coolant is particularly preferred not only from an economical and practical
point of view, but also for the fact that the cooling action is particularly efficient because of the water
evaporation.
In fact, following to the heat production due to the grinding action of the screw on the rubber material,
the water introduced into the extruder dissipates a part of the heat produced during said grinding
action and evaporates. Therefore, since the water evaporates, the rubber powder discharged from
the extruder is substantially dry.
According to the present invention, the coolant is preferably introduced into the extruder in an
amount not greater than 20% by weight with respect to the amount of the rubber material. More
preferably, the coolant amount is not greater than 10% by weight with respect to the amount of the
rubber material.
Furthermore, the vulcanized rubber material, which is reduced into a powder according to the
process of the present invention, before being introduced into the extruder, is previously broken into
pieces so as to obtain coarse particles-e. g. granules, flakes, pellets
or shreds. Preferably, said particles have dimensions not greater than 10 mm.
According to a further aspect of the present invention, the temperature of the rubber material
contained within the extruder has to be maintained below its melting or softening temperature so that
the rubber particles do not increase their tackiness during the grinding thereof and do not
agglomerate.
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In particular, the Applicant has perceived that the rubber material introduced into the extruder and
grinded by the screw thereof has to be suitably cooled by means of the coolant mentioned above so
that, at the exit of the extruder, the temperature of the rubber powder is preferably not greater than
100 C, more preferably not greater than 60 C.
Furthermore, in order to increase the grinding yield in fine particles of the rubber material, the
Applicant has found that at least one grinding aid additive can be advantageously introduced into
the extruder. In particular, the Applicant has found that a synergistic effect is obtained when at least
a coolant and a grinding aid additive are introduced into the extruder since said additive is able to
favourably support the grinding operation. As a consequence, the grinding yield in fine particles
advantageously increases.
The Applicant believes that said favourable result is connected to the fact that: a) the grinding aid
additives avoid the reagglomeration of the fine rubber particles produced during the process as well
as their sticking to the extruder barrel and screw, and b) the grinding aid additives contribute to the
grinding action thanks to their hardness and/or abrasiveness.
Preferably, said additives are introduced into the extruder by means of said at least one further
feeding inlet. More preferably, said additives are introduced
into the extruder by means of said at least one lateral feeding inlet.
Alternatively, said additives are introduced into the extruder by means of said main feeding hopper
together with the rubber material.
Preferably, said additives are introduced into the extruder by means of a gravimetric metering
device.
According to the present invention, the grinding aid additive is preferably introduced into the
extruder in an amount not greater than 20% by weight, more preferably from 0.5% to 10% by weight,
with respect to the amount of the rubber material.
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Preferably, said grinding aid additives may be selected from: silica, silicates (e. g. talc, mica, clay),
finely divided metal oxides or carbonates (e. g. calcium carbonate, zinc oxide, magnesium oxide,
alumina) and mixtures thereof.
The process of the present invention allows that high grinding yields in fine particles can be
achieved in only one pass-i. e. without recycling the obtained rubber powder-while maintaining the
process working temperature at a value remarkably higher than the working temperature of the liquid
nitrogen. In other words, in only one pass, the process of the present invention allows to obtain
grinding yields in fine particles which are comparable with those obtained with the cryogenic
techniques, but with the advantage that the process of the present invention allows important energy
and cost savings, also in terms of apparatuses to be employed.
Therefore, in only one pass, the process of the present invention allows to obtain a grinding yield
greater than 50% in particles having average diameter lower than 600 pm (i. e. 30 mesh) and a
grinding yield greater than 40% in particles having average diameter
lower than 425 pm (i. e. 40 mesh). Furthermore, a grinding yield greater than 20% in particles having
average diameter lower than 200 tm can be obtained.
According to a further embodiment of the present invention, the process comprises the step of
sieving the rubber powder exiting from the extruder. Preferably, the rubber particles having average
diameter greater than 1 mm are recycled into the extruder. Preferably, said particles are introduced
into the extruder by means of the main feeding hopper.
Therefore, according to said further embodiment, the process of the present invention further
comprises the step of recycling at least a part of the rubber powder exiting from the extruder.
The present invention is now further illustrated with reference to the attached figures, wherein: Figure 1 is a schematic diagram of a process according to the present invention; - Figure 2 is a
graphic showing the influence of water on the grinding yield of the vulcanized rubber powder
obtained from the process according to the present invention, and - Figure 3 is a graphic showing
the synergic effect of water and silica on the grinding yield of the vulcanized rubber powder.
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Figure 1 schematically shows a plant 100 for producing a rubber powder from a vulcanized rubber
material according to the present invention.
Plant 100 comprises an extruder 110 which is provided with at least one feeding inlet.
In more details, according to the embodiment shown in Figure 1, the extruder 110 comprises a main
feeding hopper llla for the introduction of the vulcanized rubber material (see arrow A) to be grinded
into powder.
According to said embodiment, the extruder 110 further comprises a lateral feeding inlet lllb and an
injection point lllc for the introduction into the extruder of at least one grinding aid additive (see arrow
B) and a coolant (see arrow C) respectively.
The extruder according to the'present invention can further comprise a cooling circuit within the
walls of the extruder barrel so that the rubber material can be cooled down also from the outside, i. e.
by contacting the cooled barrel walls.
At the extruder end opposite to the main feeding hopper, the vulcanized rubber powder is
discharged from the extruder 110 as indicated by arrow D.
According to an embodiment (not shown) of the invention, the discharged rubber powder is
conveyed to at least one sieve so that part of the powder can be recycled into the extruder,
preferably into the main feeding hopper. Preferably, the rubber particles having average diameter
greater than 1 mm are recycled.
Preferably, the extruder 110 is a co-rotating twin- screw extruder.
The vulcanized rubber material to be grinded into a powder according to the process of the present
invention may comprise at least a natural or synthetic diene elastomeric polymer, e. g. obtained by
solution polymerization, emulsion polymerization or gas-phase polymerization of one or more
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conjugated diolefins, optionally blended with at least one comonomer selected from monovinylarenes
and/or polar comonomers in an amount of not more than 60% by weight.
The conjugated diolefins generally contain from 4 to 12, preferably from 4 to 8 carbon atoms, and
may be selected, for example, from the group comprising: 1,3- butadiene, isoprene, 2, 3-dimethyl-1,
3-butadiene, 1,3- pentadiene, 1,3-hexadiene, 3-butyl-1, 3-octadiene,
2-phenyl-1, 3-butadiene, or mixtures thereof.
Monovinylarenes which may optionally be used as comonomers generally contain from 8 to 20,
preferably from 8 to 12 carbon atoms, and may be selected, for example, from: styrene; 1vinylnaphthalene ; 2- vinylnaphthalene; various alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl derivatives
of styrene such as, for example, a-methylstyrene, 3-methylstyrene, 4-propylstyrene, 4cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-p-tolylstyrene and 4- (4- phenylbutyl)
styrene, or mixtures thereof.
Polar comonomers which may optionally be used may be selected, for example, from: vinylpyridine,
vinylquinoline, acrylic and alkylacrylic acid esters, nitriles, or mixtures thereof, such as, for example,
methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, acrylonitrile, or mixtures
thereof.
Preferably, the diene elastomeric polymer may be selected, for example, from: cis-1, 4-polyisoprene
(natural or synthetic, preferably natural rubber), 3,4- polyisoprene, poly (1, 3-butadiene) (in particular
poly (1, 3-butadiene) with a high 1,4-cis content), optionally halogenated isoprene/isobutene
copolymers, 1,3-butadiene/acrylonitrile copolymers, styrene/1,3- butadiene copolymers,
styrene/isoprene/1, 3-butadiene copolymers, styrene/1, 3-butadiene/acrylonitrile copolymers, or
mixtures thereof.
Alternatively, the vulcanized rubber material to be grinded into a powder according to the process of
the present invention may comprise at least an elastomeric polymer which may be selected from
elastomeric polymers of one or more monoolefins with an olefinic comonomer or derivatives thereof.
The monoolefins may be selected from: ethylene and a-olefins generally containing from 3
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to 12 carbon atoms, such as, for example, propylene, 1- butene, 1-pentene, 1-hexene, 1-octene, or
mixtures thereof. The following are preferred: copolymers between ethylene and an a-olefin,
optionally with a diene; isobutene homopolymers or copolymers thereof with small amounts of a
diene, which are optionally at least partially halogenated. The diene optionally present generally
contains from 4 to 20 carbon atoms and is preferably selected from: 1,3-butadiene, isoprene, 1,4hexadiene, 1,4-cyclohexadiene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene,
vinylnorbornene, or mixtures thereof. Among these, the following are particularly preferred:
ethylene/propylene copolymers (EPR) or ethylene/propylene/diene copolymers (EPDM);
polyisobutene; butyl rubbers; halobutyl rubbers, in particular chlorobutyl or bromobutyl rubbers; or
mixtures thereof.
The present invention is now further illustrated by the following working examples.
*****
Example 1 (comparative)
The process was carried out by using a vulcanized rubber product produced by Graneco s. r. l.
(Ferrara- Italy). Said product was in the form of vulcanized rubber pellets having dimensions of
between 2 and 5 mm and was obained from the grinding of truck tyres.
The pellets were fed to the main feeding hopper of a co-rotating intermeshing twin-screw extruder
having a cylinder diameter of 40 mm and a L/D ratio of 48.
The feeding flow of the vulcanized rubber pellets was set to 20 kg/h and the screw rotation speed of
the extruder was set to 300 rpm.
The temperature of the vulcanized rubber powder discharged from the extruder was measured by
means of a thermocouple and a value of 56 C was obtained.
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Table 1 shows the grinding yield-expressed in percentage by weight with respect to a total amount
of 100 kg of rubber powder discharged from the extruder- with reference to different granulometric
ranges of said rubber powder.
In more details, the values of Table 1 have been obtained by sieving-for a period of time of about 6
minutes-the rubber powder discharged from the extruder by using a plurality of sieves of different
sizes. For example, the value of 69.82% corresponds to the amount by weight of rubber powder
which had a particle size greater than 1000 ssm and did not pass through the first sieve having size
of 1000 ssm, while, for example, the value of 6. 86% corresponds to the amount by weight of rubber
powder which had a particle size lower than 1000 um but higher than 800 ssm and remained on the
sieve having size of 800 Am.
From the data reported in Table 1 it can be calculated that an amount of only 4.67% of the rubber
powder discharged from the extruder had a dimension lower than 400 Am, while an amount of only
13.68% of the rubber powder had a dimension lower than 600 ssm.
The data of Example 1 are plotted in Figure 2 as indicated by curve"a"wherein in abscissa are
reported the dimensions of the rubber powder while in ordinates is indicated the grinding yield
expressed in percentage.
*****
Example 2 (invention)
The process was carried out by using the same vulcanized rubber product and the same twin-screw
extruder described in Example 1.
The twin-screw extruder was operated at the same working conditions (in terms of feeding flow and
screw rotation speed) as disclosed in Example 1.
The temperature of the vulcanized rubber powder
discharged from the extruder was of 31 C.
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4% of water-with respect to a total amount of 100 kg of rubber powder discharged from the extruderwas continuously injected into the extruder at a temperature of about 18 C. Said water was fed to the
extruder by means of an injection pump and the injection point was located at a distance of 14
diameters from the main hopper.
Table 1 shows the grinding yield-expressed in percentage by weight with respect to a total amount
of 100 kg of rubber powder discharged from the extruder- with reference to different granulometric
ranges of said rubber powder as described with reference to Example 1.
From the data reported in Table 1 it can be calculated that an amount of 10. 79% of the rubber
powder discharged from the extruder had a dimension lower than 400 m, while an amount of 24.21%
of the rubber powder had a dimension lower than 600 Am.
Therefore, by comparing the data of Example 1 with the data of Example 2, it can be observed that,
thanks to the introduction of the water into the extruder, the amount of rubber powder having
dimensions greater than 1000 jum decreased of about 16% (passing from 69.82% of Example 1 to
52.61% of Example 2) and in Example 2, with respect to the corresponding values of Example 1, the
amount of rubber powder having dimensions lower than 400 jj, m and lower than 600 pm was
increased of about 6% and 10% respectively.
The data of Example 2 are plotted in Figure 2 and indicated by curve"b".
Table 1
Grinding yield (%)
Example Example
1 2 > 1000 69. 82 52. 61
800-1000 6. 86 10. 43
600-800 9. 63 12. 75 3
400-600 9. 01 13. 42 04 r~i
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A. 4 H
300-400 3. 66 8. 35 q r,
200-300 0. 95 2. 40
100-200 0. 05 0. 05 < 100 0. 00 0. 00 *****
Example 3 (comparative)
The process was carried out by using the same vulcanized rubber product and the same twin-screw
extruder described in Example 1.
The feeding flow of the vulcanized rubber pellets was set to 40 kg/h and the screw rotation speed of
the extruder was set to 300 rpm.
The temperature of the vulcanized rubber powder discharged from the extruder was of 80 C.
Table 2 shows the grinding yield-expressed in percentage by weight with respect to a total amount
of 100 kg of rubber powder discharged from the extruder- with reference to different granulometric
ranges of said
rubber powder.
From the data reported in Table 2 it can be calculated that an amount of only 54.4% of the rubber
powder discharged from the extruder had a dimension lower than 1000 ssm, while an amount of 33.
0% had a dimension lower than 600 ym, an amount of 20.0% had a dimension lower than 420 m, an
amount of 14. 8% had a dimension lower than 350 ssm, an amount of 4.4% had a dimension lower
than 200 Am, and an amount of 1.4% had a dimension lower than 150 ssm.
The data of Example 3 are plotted in Figure 3 as indicated by curve"c"wherein in abscissa are
reported the dimensions of the rubber powder, while in ordinates is indicated the grinding yield
expressed in percentage.
*****
Example 4 (comparative)
The process was carried out by using the same vulcanized rubber product and the same twin-screw
extruder described in Example 1.
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The twin-screw extruder was operated at the same working conditions (in terms of feeding flow and
screw rotation speed) of Example 3.
The temperature of the vulcanized rubber powder discharged from the extruder was of 77 C.
A silica was used as a grinding aid additive and was introduced into the extruder through the main
feeding hopper by means of a gravimetric metering device. The silica amount was of 10% by weight
with respect to the amount of rubber material introduced into the extruder.
The silica used was Sipernato 320 which is produced by Degussa and has specific surface area of
175 m2/gr, mean particle size of 15 jj. m, Mohs hardness of 7 and density of 2. 65 g/cm3.
Table 2 shows the grinding yield-expressed in
percentage by weight with respect to a total amount of 100 kg of rubber powder discharged from
the extruder- with reference to different granulometric ranges of said rubber powder.
From the data reported in Table 2 it can be noted that, by comparing the data of Example 3 with the
data of Example 4, thanks to the introduction of the silica into the extruder, the amount of fine rubber
powder has increased. For example, it can be noted that the use of the silica has increased the
amount of the rubber powder of dimensions in the range from 200 to 350 jj. m (from 10. 40% of
Example 3 to 12,60% of Example 4, i. e. with an increment of about 21%), the amount of the rubber
powder of dimensions in the range from 150 to 200 pm (from 3. 00% of Example 3 to 5, 40% of
Example 4, i. e. with an increment of about 80%), and the amount of the rubber powder of
dimensions lower than 150 J. m (from 1. 40% of Example 3 to 11, 30% of Example 4, i. e. with an
increment of about 700%).
From the data reported in Table 2 it can be calculated that an amount of 63.5% of the rubber
powder discharged from the extruder had a dimension lower than 1000 Am, while an amount of 46.
5% had a dimension lower than 600 ssm, an amount of 34. 5% had a dimension lower than 420 Am,
an amount of 29. 3% had a dimension lower than 350 Am, an amount of 16. 7% had a dimension
lower than 200 ssm, and an amount of 11. 3% had a dimension lower than 150 ssm.
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The data of Example 4 are plotted in Figure 3 and indicated by curve"d".
*****
Example 5 (invention)
The process was carried out by using the same vulcanized rubber product and the same twin-screw
extruder described in Example 1.
The twin-screw extruder was operated at the same working conditions (in terms of feeding flow and
screw rotation speed) as disclosed in Example 3.
The temperature of the vulcanized rubber powder discharged from the extruder was of 44 C.
A silica amount of 5% by weight-with respect to the amount of rubber material introduced into the
extruder-was fed to the extruder through the main feeding hopper thereof by means of a gravimetric
metering device. The silica used was Sipernat 320 as described in Example 4.
Furthermore, a water amount of 5% by weight-with respect to the total amount of rubber materialwas continuously injected into the extruder through an injection point as described in Example 2. The
water was at a temperature of about 18 C.
Table 2 shows the grinding yield-expressed in percentage by weight with respect to a total amount
of 100 kg of rubber powder discharged from the extruder- with reference to different granulometric
ranges of said rubber powder.
From the data reported in Table 2 it can be noted that, by comparing the data of Example 4 with the
data of Example 5, thanks to the introduction into the extruder of 5% by weight of water in place of
5% by weight of silica (so that only 5% by weight of silica was used), the amount of fine rubber
powder has remarkably increased pointing out the synergic effect of silica and water. For example, it
can be noted that the amount of the rubber powder of dimensions in the range from 200 to 350 pm
has increased (from 12.6% of Example 4 to 13,4% of Example 5, i. e. with an increment of about 6%),
as well as the amount of the rubber powder of dimensions in the range
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from 150 to 200 p, m (from 5. 4% of Example 4 to 7,4% of Example 5, i. e. with an increment of about
37%), and the amount of the rubber powder of dimensions lower than 150 pm (from 11.3% of
Example 5 to 16, 2% of Example 5, i. e. with an increment of about 43%).
From the data reported in Table 2 it can be calculated that an amount of 64. 2% of the rubber
powder discharged from the extruder had a dimension lower than 1000 ssm, while an amount of
51.0% had a dimension lower than 600 ssm, an amount of 41.4% had a dimension lower than 420
Am, an amount of 37. 0% had a dimension lower than 350 ssm, an amount of 23. 6% had a
dimension lower than 200 ssm, and an amount of 16.2% had a dimension lower than 150 m.
Furthermore, by combining the data reported in Table 2, it can be noted that the addition of water
and silica to the rubber material allows to remarkably increase the grinding yield in fine particles, i. e.
in particles having dimensions lower than 350 ssm, preferably lower than 200 ism.
The data of Example 4 are plotted in Figure 3 and indicated by curve"e".
Table 2
Example Example Example
3 4 5 > 1000 45. 40 36. 40 35. 60
600-1000 21. 40 17. 00 13. 20
420-600 13. 00 12. 00 9. 60 0 Ozon
Q U 350-420 5. 20 5. 20 4. 40
200-350 10. 40 12. 60 13. 40 t
200-150 3. 00 5. 40 7. 40 < 150 1. 40 11. 30 16. 20Claims:
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CLAIMS 1. A process for producing a rubber powder from a vulcanized rubber material comprising
the steps of: feeding an extruder with said vulcanized rubber material, said extruder comprising a
barrel and at least one screw rotatably mounted into said barrel; contacting said vulcanized rubber
material with at least one coolant; operating the extruder so as to grind said vulcanized rubber
material to form said rubber powder, and discharging said rubber powder from said extruder.
2. Process according to Claim 1, wherein said step of operating the extruder comprises at least one
step of conveying the vulcanized rubber material along the extruder and at least one step of grinding
the vulcanized rubber material within the extruder.
3. Process according to Claim 1, wherein said step of contacting the rubber is carried out by
introducing said coolant into the extruder barrel.
4. Process according to Claims 3 and 2, wherein said step of introducing the coolant is performed
during said at least one step of conveying.
5. Process according to Claims 3 and 2, wherein said step of introducing the coolant is performed in
association with said at least one step of grinding.
6. Process according to Claim 5, wherein said step of introducing the coolant is performed during
said step of grinding.
7. Process according to Claim 5, wherein said step of introducing the coolant is performed before
said step of grinding.
8. Process according to Claim 3, wherein said coolant is introduced into said extruder through at
least one feeding inlet.
9. Process according to Claim 8, wherein said feeding inlet is a main feeding hopper.
10. Process according to Claim 8, wherein said feeding inlet is an injection point.
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11. Process according to Claim 8, wherein said feeding inlet is a lateral feeding inlet.
12. Process according to Claim 10 or 11, wherein said feeding inlet is positioned in correspondence
of at least one kneading element of said screw.
13. Process according to Claim 10 or 11, wherein said feeding inlet is positioned in correspondence
of a conveying element of said screw, said conveying element being positioned immediately
upstream of a kneading element of said screw.
14. Process according to Claim 10, wherein said coolant is introduced into the extruder by injection.
15. Process according to Claim 9 or 11, wherein said coolant is introduced into the extruder by
dripping.
16. Process according to Claim 1, wherein said step of contacting comprises wetting said vulcanized
rubber material with said coolant before said step of feeding.
17. Process according to Claim 1, wherein said step of contacting comprises impregnating said
vulcanized rubber material with said coolant before said step of feeding.
18. Process according to Claim 1, further comprising the step of reducing said vulcanized rubber
material into shreds before said step of feeding.
19. Process according to Claim 1, wherein said coolant is a liquid.
20. Process according to Claim 1, wherein said coolant is a non-cryogenic coolant.
21. Process according to Claim 19, wherein said coolant is water.
22. Process according to Claim 21, wherein said water is at a temperature not greater than 30 C.
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23. Process according to Claim 22, wherein said temperature is not greater than 20 C.
24. Process according to Claim 1, wherein said coolant is introduced into the extruder in an amount
not greater than 20% by weight with respect to the amount of said vulcanized rubber material.
25. Process according to Claim 24, wherein said amount is comprised between 0.5% and 10% by
weight with respect to the amount of the rubber material.
26. Process according to Claim 1, wherein the temperature of said rubber powder discharged from
the extruder is not greater than 100 C.
27. Process according to Claim 18, wherein said temperature is not greater than 60 C.
28. Process according to Claim 1, further comprising the step of introducing at least one grinding aid
additive into said extruder.
29. Process according to Claim 28, wherein said at least one grinding aid additive is selected from :
silica, silicates, metal oxides, metal carbonates, and mixtures thereof.
30. Process according to Claim 28, wherein said at least one grinding aid additive is introduced into
said extruder through at least one feeding inlet.
31. Process according to Claim 30, wherein said feeding inlet is a main feeding hopper.
32. Process according to Claim 30, wherein said feeding inlet is a lateral feeding inlet.
33. Process according to Claim 28, wherein said at least one grinding aid additive is introduced into
the extruder in an amount not greater than 20% by weight with respect to the amount of said
vulcanized rubber material.
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34. Process according to Claim 33, wherein said amount is comprised between 0. 5% and 10% by
weight with respect to the amount of the rubber material.
35. Process according to Claim 1, further comprising the step of sieving said rubber powder
discharged from said extruder.
36. Process according to Claim 35, further comprising the step of recycling at least part of said
rubber powder after said step of sieving.
37. Process according to Claim 1, wherein said extruder is a co-rotating twin-screw extruder.
38. Process according to Claim 1, wherein said vulcanized rubber material comprises at least one
synthetic or natural elastomeric polymer.
39. Process according to Claim 1, wherein said vulcanized rubber material derives from discarded
tyres.
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36. WO2004052981 - 24.06.2004
METHOD FOR VULCANIZING A RUBBER COMPOUND, AND RUBBER ARTICLES MANUFACTURED
FROM A VULCANIZED RUBBER COMPOUND AS OBTAINED WITH THE METHOD
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO2004052981
Inventor(s):
VAN BAARLE BERNARD [NL] (--); HEIDEMAN GEERT [NL] (--); NOORDERMEER
JACOBUS WILHELMUS [NL] (--)
Applicant(s): TNO [NL] (--); VAN BAARLE BERNARD [NL] (--); HEIDEMAN GEERT [NL] (--);
NOORDERMEER JACOBUS WILHELMUS [NL] (--)
IP Class 4 Digits: C08K; C08J; C08L
IP Class:
C8K9/02; C8K9/12; C8J3/24; C8L21/00
E Class: C08K9/02+L21/00; C08K9/12+L21/00
Application Number:
WO2003NL00880 (20031211)
Priority Number: NL20021022146 (20021211)
Family: WO2004052981
Equivalent:
NL1022146
Cited Document(s):
US4331706; US2399947; JP49130893
Abstract:
THE INVENTION RELATES TO A METHOD FOR VULCANIZING A RUBBER COMPOUND, WHEREIN
THE RUBBER COMPOUND, UNDER HEATING, IN THE PRESENCE OF SULFUR OR A SULFURCONTAINING COMPOUND, AND A VULCANIZATION ACCELERATOR, IS CONTACTED WITH AN
ACTIVATOR COMPRISING A SUPPORT MATERIAL LOADED WITH BA, PD, CD, CA, MG AND/OR
ZN IONS PROVIDED ON THE SUPPORT MATERIAL THROUGH AN ION EXCHANGE PROCESS
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WITH A METAL ION-CONTAINING SOLUTION. THE INVENTION ALSO RELATES TO RUBBER
ARTICLES MANUFACTURED FROM A VULCANIZED RUBBER COMPOUND AS OBTAINED WITH
THE METHOD ACCORDING TO THE INVENTION.Description:
Title: Method for vulcanizing a rubber compound, and rubber articles manufactured from a
vulcanized rubber compound as obtained with the method
The invention relates to a method for vulcanizing a rubber compound, and rubber articles
manufactured from a vulcanized compound as obtained with the method according to the invention.
Rubber compounds normally need to be vulcanized with sulfur or a sulfur-containing compound to
ensure that they have the proper physical properties that are needed for the various applications.
The vulcanization is usually carried out at elevated temperature and in the presence of a
vulcanization accelerator because the vulcanization as such proceeds slowly.
To further improve the physical properties of the rubber vulcanisates to be obtained, the
vulcanization is normally carried out in the presence of a vulcanization catalyst or activator. Typically,
zinc oxide is used as activator, often in combination with stearic acid in compounds containing sulfur.
As a most important application, zinc oxide is used in the preparation of rubber compounds that are
used in tires. In tire treads, zinc has the drawback that through wear of the car tires, tire grindings
end up in the surface water.
Given the fact that zinc is a heavy metal unfortunately having a harmful effect on microorganisms, it
will be clear that a reduction of the zinc concentration in tires for transport purposes, for instance car
tires, would be very favorable to the environment.
Surprisingly, it has now been found that rubber compounds can be vulcanized utilizing a specific
activator that contains no zinc or substantially less zinc, which is highly favorable to the environment.
Accordingly, the invention relates to a method for vulcanizing a rubber compound, wherein the
rubber compound, under heating, in the presence of sulfur or a sulfur-containing compound, and a
vulcanization accelerator, is contacted with an activator comprising a support material
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loaded with Ba, Pd, Cd, Ca, Mg and/or Zn ions provided on the support material through an ion
exchange process with a metal ion-containing solution. Preferably, the support material is loaded
with zinc ions.
The rubber compounds that can be used according to the invention are generally known and can be
selected from the group of polymers such as natural rubber, styrene butadiene rubber, polyisoprene
rubber, nitrile butadiene rubber and ethylene propylene diene rubber.
Preferably, the support material of the activator is a clay, though not limited to the groups mentioned.
Suitable clays can be selected from the group of the halloysite, illite, kaolinite, bentonite,
phyllosilicate, and/or palygorskite-like clays. Halloysite-like clays can be suitably selected from the
group of allophane, endellite, halloysite, indianite, metahalloysite and schrotterrite. Suitable illite-like
clays can be selected from the group of brammallite, bravaisite, glimmerton, hydromica and sercicite.
Suitable kaolinite-like clays can be selected from the group of anauxite or ionite, collyrite, dickite,
ferrikaolinite, nacrite, neokaolin, metakaolin, metanacrite and severite. Suitable montmorillonite-like
clays can be selected from the group of beidellite, bentonite, chloropal, erinite, ferrimontmorillonite,
hectorite, metabentonite, montmorillonite, nontronite, otaylite and saponite.
A suitable phyllosilicate-like clay is vermiculite. Palygorskite-like clays can be suitably chosen from
the group of attapulgite, calciopalygorskite, lassalite, palygorskite, paramontmorillonite, parasepiolite
and sepiolite.
Such support materials can be suitably used in the method according to the invention because they
contain (relatively) large amounts of exchangeable ions (Ca, Mg, Na).
Preferably, according to the invention, a clay is used from the group of bentonite and phyllosilicate.
Particularly suitable supports herein are bentonite, montmorillonite and vermiculite.
These support materials are further described in U. S. Patent
3,902, 886.
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The metal loading of the activator is generally 0.1-30 wt. %, calculated on the support material. In a
suitable embodiment, the metal loading is 1-15 wt. %, calculated on support material. Preferably, the
metal loading is 3-7wt. %, and more preferably 4-6 wt. %, calculated on support material.
In a suitable embodiment, the amount of activator is 0.1-20 wt. %, calculated on the rubber
compound. Preferably, the amount of activator is 1-7 wt. %, calculated on the rubber compound, and
more preferably the amount of activator is 2.5-5 wt. %, calculated on the rubber compound.
With respect to the conventional zinc oxide activator, the proposed activator allows the zinc content
to be reduced by a factor of 20 if the activator is loaded with zinc, or allows the zinc to be actually
replaced with other metals. The activator that is used according to the invention can be suitably
prepared by subjecting the support material to an ion exchange process with a metal ion-containing
solution. Preferably, a zinc ioncontaining solution is used. Suitable zinc ion-containing solutions can
be selected from the group of zinc chloride, zinc nitrate and zinc acetate.
Preferably, in the ion exchange process, use is made of a metal chloride solution and more
preferably of a zinc chloride solution.
In a suitable embodiment of the invention, the ion exchange process is carried out at a temperature
of 15-30 C for 10-24 hours at a pH of 6-8.
Preferably, the ion exchange process is carried out at a temperature of 20-25 C for 12-18 hours, and
at a pH of 6.5-7. 5. The support material can be contacted under movement, for instance with
shaking, with a metal ion- containing solution, preferably zinc chloride solution (for instance a 1M
zinc chloride solution) for 2-8 hours. Next, the slurry obtained can be suitably dialyzed with, for
instance, demineralized water until it is essentially anion- free. The thus obtained slurry can then be
dried for 8-16 hours at a temperature of 65-70 C. Next, the thus obtained support material can, if
desired, be ground and screened, whereby a particle size of less than 38 microns can be obtained.
351/425
Preferably, the support material is treated with an acid before being subjected to the ion exchange
process. Suitable acids can be selected from the group of hydrogen chloride and hydrogen sulfide
acid. More preferably, as an acid, hydrogen chloride is used, for instance a solution of 20%
hydrogen chloride.
The treatment with acid is suitably carried out at a temperature of 15-30 C for 2-8 hours, and at a pH
of 1-4. Preferably, the treatment with acid is carried out at a temperature of 20-25 C for 3-5 hours,
and at a pH of 1-2. Next, the obtained slurry can be neutralized with an alkaline solution, for instance
a NaOH solution, until it has acquired a pH of 6.5-7. Next, the neutralized slurry can be suitably
dialyzed, with, for instance, demineralized water, until the compound is substantially free of anions.
Then, the slurry can be dried, for 8-16 hours at a temperature of 65-70 C, after which the obtained
support material can be ground and screened, whereby a particle size of less than 38 microns can
be obtained.
In the method according to the invention, preferably sulfur is used as vulcanizing agent. The amount
of sulfur can be 0.5-3 wt. %, calculated on the rubber compound. Preferably, the amount of sulfur is
1-2 wt. %, calculated on the rubber compound.
In the method according to the invention, use can be made of generally known vulcanization
accelerators. Suitable vulcanization accelerators can be selected from the group of xanthates,
carbamates, thiazoles, sulfenamides, thiurams, and guanidines, as described in Dutch patent
specification 185670. Preferably, a vulcanization accelerator is selected from the group of
sulfenamides.
The vulcanization accelerator can be present in an amount of 1-5 wt. %, calculated on the rubber
compound. Preferably, the vulcanization accelerator is present in an amount of 2-4 wt. %, calculated
on the rubber compound.
It will be clear to the skilled person that the choice of the vulcanization accelerator will depend on
the conditions under which the vulcanization process will be carried out.
352/425
Depending on the type of accelerator and vulcanization temperature, the vulcanization can be
suitably carried out between 20-210 C, while for compression molding generally a temperature of
140-180 C is selected and for injection molding a temperature of 170-210 C. Continuous
vulcanization can be carried out in a salt bath or hot air tunnels, with and without UHF with
temperatures of 140 C to ca. 500 C.
The invention further relates to rubber articles manufactured with a vulcanized rubber compound as
obtained with the method according to the invention. Such rubber articles can be products such as
tires for transport purposes such as car tires, airplane tires and tires for motorcycles, conveyor belts,
(heating) hoses, driving belts, roller covering, electrical insulations, etc. In addition, the rubber
articles can be sealing profiles for automobiles, radiator hoses, roof foil and membranes. Preferably,
the invention furthermore relates to a tire for transport purposes, and more preferably a car tire, that
is manufactured from the vulcanized rubber compound as obtained with the method according to the
invention.
Further, customary additives may be added to the rubber compound, such as black, plasticizers,
clay, silica, pigments, antioxidants, antiozonants, delaying agents, and processing aids such as, for
instance, fatty acids and process oils.
Example 1 A master batch was prepared, consisting of 100 parts of s-SBR Buna VSL 2525-0 (a
solution SBR having a high content of polymer (98%); 50 parts N 375 (carbon black); and 5 parts of
Enerflex 75 (aromatic oil). Using a laboratory roll, a vulcanization system was added to the master
batch. The vulcanization system consisted of 2.5 parts of zinc clay; 2 parts of stearic
acid; 1.75 parts of sulfur ; and 1.50 parts of N-tert. butyl-benzothiazyl sulfenamide (accelerator), the
parts being calculated on 100 parts of polymer (see also Table 1). Twenty-five grams of
Montmorillonite were refluxed for 4 hours with an excess of HCl (20%), and neutralized with a solution
of 25% sodium hydroxide solution to pH 7. Next, the zinc clay was prepared by subjecting the acidtreated support material to an ion exchange process. The ion exchange was carried out with 12.5
grams of treated support material and 125 ml of a 1M zinc chloride solution, with shaking, at a
temperature of 20 C, for 16 hours. Next, the obtained slurry was dialyzed with demineralized water
until it was essentially anion-free. The thus obtained slurry was then dried for 12 hours at a
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temperature of 70 C. Next, the thus obtained zinc clay was ground and screened, whereby a particle
size of 63 microns at a maximum was obtained. The zinc clay comprised 4.5 wt. % of zinc,
calculated on. Montmorillonite. The obtained mixture of the master batch and the vulcanization
system was vulcanized for 30 minutes at a temperature of 160 C and a pressure of ca. 10 Bar. The
obtained vulcanisate was then stored for 16 hours at 23 C, after which mechanical and physical
properties of the vulcanisate were determined (see Table 2).
Example 2 A vulcanization process as described in Example 1 was carried out, except that in the
vulcanization system, instead of 2.5 parts of zinc clay, 5 parts of zinc oxide were used as zinc
activator. The composition of the obtained compound of the master batch and the vulcanization
system is shown in Table 1. The mechanical and physical properties of the obtained vulcanisate are
shown in Table 2.
Tables 1 and 2 clearly show that surprisingly good and comparable mechanical and physical
product properties can be obtained using the
vulcanization process according to the invention, while the zinc concentration used has been
reduced by as much as a factor of 20 (from 2.42% to 0.12%).
Table 1
Compound Example 2 Example 1
composition (parts) (parts)
s-SBR VSL 2525 100 100
Carbon Black N375 50 50
Enerflex 75 5 5
Sulfur 1. 75 1. 75
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TBBS* 1.5 1.5
Stearic acid 2 2
Zinc clay (activator)-2. 5
ZnO (activator) 5Zn-conc. (wt. %) 2. 42 0. 12
Table 2
Properties Example 2 Example 1
Tensile strength (MPa) 23. 1 21. 9
Elongation-at-break (%) 458 440
Modulus 100 (MPa) 2. 6 2. 7
Modulus 200 (MPa) 6. 7 6. 9
Modulus 300 (MPa) 12. 7 13. 0
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Tear strength (N) 36 36
Hardness (Shore A) 65 65
Compression Set 8 10
3 days 23 C (%)
Examples 3 and 4 (latex variants) Two aqueous dispersions were prepared in a small 0.25 liter-ball
mill with ceramic balls of a diameter of 8 mm. The grinding time in the ball mill was 24 hours. The
compositions of the prepared dispersions are shown in Table 3. The latex compounds were
prepared according to the formulations in Table 4. The latex compounds were subsequently stored
for five days at room temperature. Of the two qualities, small molded plates were manufactured in
metal frames on a glass plate. The drying time was 24 hours. The plates were subsequently dried
further for 1 hour at 70 C. Of each rubber quality, two plates were vulcanized at 100 C for 1 hour. Of
these plates, physicomechanical properties were determined, listed in Table 5.
Table 3: Dispersions of zinc oxide and Zinc clay
Latex dispersion Example 3 Example 4
composition Dispersion 1 Dispersion 2
(parts) (parts)
ZnO (red seal) 60
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Zinc clay 25
Demi water 37. 4 73. 2
Darvan Nol 2.0 0.8
28% ammonia 0.6 1.0
Total 100 100
Table 4: Latex compounds
Latex compound Example 3 Example 4
composition Compound 1 Compound 2
(parts) (parts)
NR latex LATZ 167 167
Dispersion 1 (ZnO) 6
Dispersion 2 (zinc clay) 14.4
Vulcanization 4 4
dispersion
28% ammonia 0.6 0.6
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Total 177. 6 186
Table 5 : Physicomechanical properties of vulcanized latex plates
Properties Mixture Mixture
12
Tensile properties
- tensile strength [MPa] 33.6 28.8
- modulus at 50% 0.6 0.6
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[MPa]
- modulus at 100% k 0.8 0.8
[MPa]
- modulus at 300% 1. 5 1.5
[MPa]
- elongation at break 820 810
[%]
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permanent deformation
- after 24 h at 70 C, [%] 36 34
- after 72 h at 23 C, [%] 11 10
The measured physicomechanical properties demonstrate that there are no great differences
between the latex qualities examined. The values for the tensile strengths are high, the moduli are
comparable. The permanent deformation after storage at 70 C of the compound with zinc clay is of
equal value as the compound with zinc oxide. This is an indication that the compound with zinc clay
has reached a good degree of vulcanization after 1 hour of vulcanization at 100 C.Claims:
CLAIMS 1. A method for vulcanizing a rubber compound, wherein the rubber compound, under
heating, in the presence of sulfur or a sulfur-containing compound, and a vulcanization accelerator,
is contacted with an activator comprising a support material loaded with Ba, Pd, Cd, Ca, Mg and/or
Zn ions provided on the support material through an ion exchange process with a metal ioncontaining solution.
2. A method according to claim 1, wherein the support material of the activator is a clay.
3. A method according to claim 1 or 2, wherein the support material is loaded with Zn ions.
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4. A method according to 2 or 3, wherein the clay is selected from the group of the halloysite-, illite-,
kaolinite-, montmorillonite-, bentonite-, phyllosilicate-and/or palygorskite-like clays.
5. A method according to claim 4, wherein the clay is selected from the group of montmorillonite,
vermiculite and/or bentonite.
6. A method according to any one of claims 1-5, wherein the metal content is 0. 1-30 wt. %,
calculated on the support material.
7. A method according to claim 6, wherein the metal content is 1-15 wt. %, calculated on the support
material.
8. A method according to any one of claims 1-7, wherein the support material is treated with an acid
before being subjected to the ion exchange process.
9. A method according to any one of claims 1-8, wherein the ion exchange process is carried out
with a metal chloride solution.
10. A method according to any one of claims 1-9, wherein the vulcanization accelerator is selected
from the group of sulfenamides.
11. A method according to any one of claims 1-10, wherein the vulcanization is carried out at a
temperature of 20-210 C.
12. A rubber article manufactured from a vulcanized rubber compound as obtained with the method
according to any one of claims 1-11.
13. A rubber article according to claim 12, which article is a tire for transportation purposes.
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37. WO2004087803 - 14.10.2004
THERMOPLASTIC MATERIAL COMPRISING A VULCANIZED RUBBER IN A SUBDIVIDED FORM
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO2004087803
Inventor(s):
TIRELLI DIEGO [IT] (--); GALBUSERA MICHELE [IT] (--); CASTELLANI LUCA [IT] (-); PERUZZOTTI FRANCO [IT] (--); ALBIZZATI ENRICO [IT] (--)
Applicant(s): PIRELLI and C SPA [IT] (--); TIRELLI DIEGO [IT] (--); GALBUSERA MICHELE [IT] (-); CASTELLANI LUCA [IT] (--); PERUZZOTTI FRANCO [IT] (--); ALBIZZATI ENRICO [IT] (--)
IP Class 4 Digits: C08L
IP Class:
C8L21/00; C8L23/16; C8L23/10; C8L23/12; C8L19/00
Application Number:
WO2003EP03336 (20030331)
Priority Number: WO2003EP03336 (20030331)
Family: WO2004087803
Cited Document(s):
US6031009; US5798413; US6262175
Abstract:
THE PRESENT INVENTION RELATES TO A THERMOPLASTIC MATERIAL COMPRISING; A) FROM
5% WEIGHT TO 95% BY WEIGHT, PREFERABLY FROM 10% BY WEIGHT TO 60% BY WEIGHT, OF
VULCANIZED RUBBER IN A SUBDIVIDED FORM; B) FROM 5% BY WEIGHT TO 95% BY WEIGHT,
PREFERABLY FROM 40% BY WEIGHT TO 90% BY WEIGHT, OF AT LEAST ONE HETEROPHASE
COPOLYMER COMPRISING A THERMOPLASTIC PHASE MADE FROM A PROPYLENE
HOMOPOLYMER OR COPOLYMER AND AN ELASTOMERIC PHASE MADE FROM A COPOLYMER
OF ETHYLENE WITH AN ALPHA-OLEFIN, PREFERABLY WITH PROPYLENE; C) FROM 0& BY
WEIGHT TO 90% BY WEIGHT, PREFERABLY FROM 0% BY WEIGHT TO 50% BY WEIGHT, OF AT
LEAST ONE ALPHA-OLEFIN HOMOPOLYMER OE COPOLYMER DIFFERENT FROM B); THE
AMOUNTS OF A), B), C) BEING EXPRESSED WITH RESPECT TO THE TOTAL WEIGHT OF A), B)
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AND C) BEING EXPRESSED WITH RESPECT TO THE TOTAL WEIGHT OF A) + B) + C). SAID
THERMOPLASTIC MATERIAL SHOWS IMPROVED MECHANICAL PROPERTIES, IN PARTICULAR,
IMPROVED ELONGATION AT BREAK.Description:
THERMOPLASTIC MATERIAL COMPRISING A VULCANIZED RUBBER IN A SUBDIVIDED FORM.
The present invention relates to a thermoplastic material comprising a vulcanized rubber in a
subdivided form.
In particular, the present invention relates to a thermoplastic material comprising a vulcanized
rubber in a subdivided form and at least one heterophase copolymer comprising a thermoplastic
phase made from a propylene homopolymer or copolymer and an elastomeric phase made from a
copolymer of ethylene with an a-olefin.
The present invention moreover relates to a manufactured product comprising said thermoplastic
material.
The increased production of industrial rubber products has resulted in the accumulation of large
amounts of rubber wastes which per se do not find any practical applications and are generally
disposed in dedicated landfills with the main drawbacks of environment pollution as well as of the
need for large dedicated areas for storing said wastes.
It is known in the art to depolymerize waste stream of rubber, such as tyres, in an effort to reduce the
volume of waste and obtain a useful byproduct. Likewise, rubber product may be devulcanized in an
attempt to recycle the waste rubber.
In addition to these techniques, it is common in the art to grind the waste streams of rubber and
utilize the ground particles so obtained. These ground particles are then typically compounded with
other polymeric materials in order to make final product which may be employed in a plurality of
applications.
However, it has been found that the addition of such ground rubber particles to the polymeric
material results in a significant deterioration of the mechanical
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properties of the resulting polymeric composites.
Many efforts have been made in the art in order to overcome the above reported problems.
For example, patent US 5,010, 122 relates to thermoplastic compositions comprising rubber
particulate having a size less than about 10 mesh, a thermoplastic material, and at least one
coupling agent. The thermoplastic material preferably comprises an olefin, a co-polymer of an olefin,
a homopolymer of an olefin, or blends thereof. The coupling agent preferably comprises a silane
coupling agent. The abovementioned thermoplastic compositions are said to have excellent physical
properties.
Patent US 5,157, 082 relates to thermoplastic compositions comprising mixtures of ground
vulcanized rubber, polyolefin resin, and at least one functionalized olefin polymer which may be
selected from a copolymer of at least one olefin and at least one ethylenically unsaturated organic
monomer. The polyolefin resin is a solid, high molecular weight polymeric material made by
polymerizing one or more olefinic monomers in a conventional manner. Preferred polyolefin resins
are polyethylene or polypropylene. Also suitable for the practice of the invention are copolymers of
two or more olefins with copolymers of ethylene and propylene being preferred. The abovementioned
thermoplastic compositions are said to have improved mechanical properties.
Patent US 5,889, 119 relates to a thermoplastic rubbery composition comprising (I) from about 10 to
about 40 parts by weight of a low-modulus binder including : (a) from about 75 to about 25 parts by
weight of a crystalline polyolefin resin, and (b) from about 25 to about 75 parts by weight of a binder
rubber in the form of particles having an average diameter of less than about 20 pm, said binder
rubber having been dynamically vulcanized; and (II)
from about 90 to greater than 50 parts by weight of ground vulcanized rubber particles having an
average diameter in the range of from about 50 ssm to about 1.2 mm. The polyolefin resins are
preferably high density polyethylene or polypropylene. The abovementioned thermoplastic rubbery
composition is said to have improved physical properties.
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Patent US 6,015, 861 relates to a method of preparing a rubber-blend thermoplastic composition,
comprising the steps of: (a) providing a ground crosslinked rubber having an average particle size of
about 80 mesh or smaller ; and (b) combining the ground crosslinked rubber with a thermoplastic
polyolefinic material and a compatibilizer based on a paraffinic oil to form a blend thermoplastic resin
composition. The preferred thermoplastic polyolefinic material are polyethylene, polypropylene,
ethylene copolymers, propylene copolymers, poly (ethylene propylene) copolymers, and mixtures
thereof. The composition prepared by the abovementioned method is said to include a surprisingly
high level of recycle rubber without adverse effect on its physical or aesthetic properties.
Patent US 6,031, 009 relates to thermoplastic compositions comprising a blend of ground
vulcanized rubber, at least one conventional olefin polymer and at least one metallocene single site
catalyzed a-olefin copolymer. The olefin polymer is a solid, high molecular weight polymeric material
made by polymerizing one or more olefinic monomers in a conventional manner. Preferred olefin
polymers are polyethylene or polypropylene. The abovementioned thermoplastic compositions are
said to have improved mechanical properties.
International Patent Application WO 00/78852 relates to a method for producing an elastomeric alloy
similar to thermoplastic elastomers using reclaimed or waste rubber.
To this end, a polypropylene copolymer or a mixture
thereof with at least one polypropylene type, is melted in a mixer. Subsequently, powdered rubber,
at least a part of which is pre-swollen in a radical donor, is added to the melt in a metered quantity,
the powdered rubber is dispersed in the plastic matrix by applying high shear forces whilst adding
radical-forming agents in accordance with defined mixing parameters to produce a phase coupling
between the powdered rubber and the polypropylene copolymer or a mixture thereof. The obtained
elastomeric alloy is said to have properties similar to thermoplastic elastomers.
Patent US 6,262, 175 relates to a thermoplastic composition containing, in percentages by weight
based on the total weight of the composition: about 5% to about 90% of vulcanized rubber crumb;
about 5% to about 60% polyolefin; about 2% to about 30% uncured rubber or styrene-based
thermoplastic elastomer; and about 2% to about 30% vinyl polymer selected from vinyl
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homopolymers, copolymers and mixtures thereof. The polyolefin is a solid, high molecular weight
polyolefin homopolymer or copolymer, or mixtures thereof. Preferred polyolefin are polyethylene,
polypropylene, or a copolymer of ethylene and propylene. The abovementioned thermoplastic
composition is said to have excellent physical properties, including excellent ultimate elongation and
tear strength.
International Patent Application WO 02/24795 relates to a method for recycling a thermoset rubber
material comprising subjecting a recycled thermoset rubber material to a phase compatibility
treatment with an oxidizing agent and blending the recycled thermoset rubber material with a
thermoplastic polymer to obtain a material selected from the group consisting of a thermoplastic
elastomer and an impact-strengthened thermoplastic. Polyolefins (e. g. polypropylene) are among
the more preferred thermoplastic polymers.
The Applicant noticed that compatibility problems between the vulcanized rubber in a subdivided
form and the thermoplastic polymers, in particular in the case of polypropylene and its copolymers,
still exhist notwithstanding the efforts of the prior art. Said compatibility problems negatively affect the
mechanical properties of the obtained thermoplastic material.
The Applicant has now found that it is possible to overcome the above mentioned problems utilizing,
as a thermoplastic polymer, a heterophase copolymer comprising a thermoplastic phase made from
a propylene homopolymer or copolymer and an elastomeric phase made from a copolymer of
ethylene with an a-olefin. Said heterophase copolymer shows an improved compatibility with the
ground vulcanized rubber and allows to obtain a thermoplastic material having good mechanical
properties, in particular elongation at break, stress at break and/or impact resistance. More in
particular, said thermoplastic material shows an improved elongation at break.
According to a first aspect, the present invention relates to a thermoplastic material comprising: (a)
from 5% by weight to 95% by weight, preferably from 10% by weight to 60% by weight, of a
vulcanized rubber in a subdivided form; (b) from 5% by weight to 95% by weight, preferably from
40% by weight to 90% by weight, of at least one heterophase copolymer comprising a thermoplastic
phase made from a propylene homopolymer or copolymer and an elastomeric phase made from a
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copolymer of ethylene with an a-olefin, preferably with propylene ; (c) from 0% by weight to 90% by
weight, preferably from 0% by weight to 50% by weight, of at least one a-olefin homopolymer or
copolymer different from (b); the amounts of (a), (b) and (c) being expressed with respect to the total
weight of (a) + (b) + (c).
For the aim of the present description and of the claims which follow, the expression"heterophase
copolymer comprising a thermoplastic phase made from a propylene homopolymer or copolymer
and an elastomeric phase made from a copolymer of ethylene with an a-olefin"means a thermoplastic
elastomer obtained by sequential copolymerization of: (i) propylene, optionally containing small
amounts of at least one olefinic comonomer selected from ethylene and a-olefins other than
propylene; and then of: (ii) a mixture of ethylene with an a-olefin, in particular propylene, and
optionally with small proportions of a polyene, in particular a diene. This class of products is also
commonly known as"thermoplastic reactor elastomers".
The vulcanized rubber in a subdivided form (a) which may be used in the present invention may be
obtained by grinding or otherwise comminuting any source of vulcanized rubber compound such as,
for example, tyres, roofing membranes, hoses, gaskets, and the like, and is preferably obtained from
reclaimed tyres using any conventional method. For example, the vulcanized rubber in a subdivided
form may be obtained by mechanical grinding at ambient temperature or in the presence of a
cryogenic coolant (i. e. liquid nitrogen). Any steel or other metallic inclusions should be removed
from the ground tyres before use. Since the thermoplastic material of the present invention is
preferably fiber-free, all fibrous material such as, for example, tyre cord fibers, is preferably removed
from the ground rubber using conventional separation methods.
According to one preferred embodiment, the vulcanized rubber in a subdivided form (a) which may
be used in the present invention, is in the form of powder or granules having a particle size not
higher than 10 mm, preferably not higher than 5 mm.
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According to a more preferred embodiment, the vulcanized rubber in a subdivided form (a) which
may be used in the present invention, has a particle size not higher than 0.6 mm, preferably not
higher than 0.5 mm, more preferably not higher than 0.2 mm.
According to one preferred embodiment, the vulcanized rubber in a subdivided form (a) may
comprises at least one diene elastomeric polymer or copolymer which may be of natural origin or
may be obtained by solution polymerization, emulsion polymerization or gas-phase polymerization of
one or more conjugated diolefins, optionally blended with at least one comonomer selected from
monovinylarenes and/or polar comonomers in an amount of not more than 60% by weight.
The conjugated diolefins generally contain from 4 to 12, preferably from 4 to 8 carbon atoms, and
may be selected, for example, from the group comprising: 1,3- butadiene, isoprene, 2, 3-dimethyl-1,
3-butadiene, 1,3- pentadiene, 1,3-hexadiene, 3-butyl-1, 3-octadiene, 2-phenyl-1, 3-butadiene, or
mixtures thereof.
Monovinylarenes which may optionally be used as comonomers generally contain from 8 to 20,
preferably from 8 to 12 carbon atoms, and may be selected, for example, from: styrene; 1vinylnaphthalene ; 2-vinylnaphthalene; various alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl derivatives
of styrene such as, for example, a- methylstyrene, 3-methylstyrene, 4-propylstyrene, 4cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4- benzylstyrene, 4-p-tolylstyrene, 4- (4-phenylbutyl)
styrene, or mixtures thereof.
Polar comonomers which may optionally be used may be selected, for example, from: vinylpyridine,
vinylquinoline, acrylic acid and alkylacrylic acid esters, nitriles, or mixtures thereof, such as, for
example, methyl acrylate, ethyl acrylate, methyl methacrylate,
ethyl methacrylate, acrylonitrile, or mixtures thereof.
Preferably, the diene elastomeric polymer or copolymer may be selected, for example, from: cis-1,
4-polyisoprene (natural or synthetic, preferably natural rubber), 3, 4- polyisoprene, polybutadiene (in
particular polybutadiene with a high 1, 4-cis content), optionally halogenated isoprene/isobutene
copolymers, 1, 3-butadiene/acrylonitrile copolymers, styrene/1,3-butadiene copolymers,
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styrene/isoprene/1,3-butadiene copolymers, styrene/1,3- butadiene/acrylonitrile copolymers, or
mixtures thereof.
Alternatively, the vulcanized rubber in a subdivided form (a) may comprise at least one elastomeric
polymer of one or more monoolefins with an olefinic comonomer or derivatives thereof. The
monoolefins may be selected from: ethylene and a-olefins generally containing from 3 to 12 carbon
atoms, such as, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, or mixtures
thereof. The following are preferred: copolymers between ethylene and an a-olefin, optionally with a
diene; isobutene homopolymers or copolymers thereof with small amounts of a diene, which are
optionally at least partially halogenated. The diene optionally present generally contains from 4 to 20
carbon atoms and is preferably selected from: 1, 3-butadiene, isoprene, 1,4-hexadiene, 1,4cyclohexadiene, 5-ethylidene-2-norbornene, 5- methylene-2-norbornene, vinylnorbornene, or
mixtures thereof. Among these, the following are particularly preferred: ethylene/propylene
copolymers (EPR) or ethylene/propylene/diene copolymers (EPDM); polyisobutene; butyl rubbers ;
halobutyl rubbers, in particular chlorobutyl or bromobutyl rubbers; or mixtures thereof.
For the aim of the present description and of the claims which follows, the term" (X-olefin" generally
means an aliphatic a-olefin of formula CH2=CH-R, wherein R represents a hydrogen atom, or a linear
or branched alkyl
group containing from 1 to 12 carbon atoms.
Preferably, the aliphatic a-olefin is selected from: ethylene, propylene, 1-butane, isobutylene, 1pentane, 1- hexene, 3-methyl-l-butene, 3-metlyl-1-pentene, 4-methyl-1- pentene, 4-methyl-l-hexene, 4,
4-dimethyl-l-hexene, 4, 4- dimethyl-l-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1- octene, 1decene, 1-dodecene, 1-tetradecene, 1-hexadecene, l-octadecene, 1-eicosene, or mixture thereof. Of
these, preferred are ethylene, propylene, 1-butene, 1-hexene, 1- octene, or mixtures thereof.
For the aim of the present description and of the claims which follows, the term"polyene"generally
means a conjugated or non-conjugated diene, triene or tetraene.
When a diene comonomer is present, this comonomer generally contains from 4 to 20 carbon atoms
and is preferably selected from: linear conjugated or non- conjugated diolefins such as, for example,
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1, 3-butadiene, 1,4-hexadiene, 1,6-octadiene, and the like; monocyclic or polycyclic dienes such as,
for example, 1,4- cyclohexadiene, 5-ethylidene-2-norbornene, 5-methylene-2- norbornene,
vinylnorbornene, or mixtures thereof. When a triene or tetraene comonomer is present, this
comonomer generally contains from 9 to 30 carbon atoms and is preferably selected from trienes or
tetraenes containing a vinyl group in the molecule or a 5-norbornen-2-yl group in the molecule.
Specific examples of triene or tetraene comonomers which may be used in the present invention are:
6, 10-dimethyl-1, 5,9-undecatriene, 5, 9-dimethyl-1, 4,8- decatriene, 6, 9-dimethyl-1, 5,8-decatriene,
6,8, 9- trimethyl-1, 6,8-decatriene, 6,10, 14-trimethyl-1, 5,9, 13- pentadecatetraene, or mixtures
thereof. Preferably, the polyene is a diene.
As disclosed above, the heterophase copolymer (b) is prepared by sequential copolymerization of:
(i) propylene, optionally containing at least one olefinic comonomer
chosen from ethylene and a-olefins other than propylene; and then of: (ii) a mixture of ethylene with
an a-olefin, in particular propylene, and optionally a polyene, in particular a diene. The
copolymerization is usually carried out in the presence of Ziegler-Natta catalysts based on
halogenated titanium compounds supported on magnesium chloride in admixture with an aluminium
trialkyl compound wherein the alkyl groups contains from 1 to 9 carbon atoms such as, for example,
aluminium triethyl or aluminium triisobutyl. More details regarding the preparation of the heterophase
copolymer (b) are given, for example, in European Patent Applications EP 400,333 and EP 373,660
and in patent US 5,286, 564.
The thermoplastic phase of the heterophase copolymer (b), mainly produced during the
abovementioned phase (i) of the process, consists of a propylene homopolymer or a copolymer of
propylene with an olefinic comonomer selected from ethylene and a-olefins other than propylene.
Preferably, the olefinic comonomer is ethylene. The amount of olefinic comonomer is preferably less
than 10 mol% relative to the total number of monomer moles in the thermoplastic phase.
The elastomeric phase of the heterophase copolymer (b), mainly produced during the
abovementioned phase (ii) of the process, is at least 10% by weight, preferably at least 40% by
weight, more preferably at least 60% by weight, relative to the total weight of the heterophase
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copolymer, and consists of an elastomeric copolymer of ethylene with an a-olefin and optionally with
a polyene.
Said a-olefin is preferably propylene ; said polyene is preferably a diene. The diene optionally
present as comonomer generally contains from 4 to 20 carbon atoms and is preferably selected from:
linear (non-) conjugated diolefins such as, for example, 1, 3-butadiene, 1,4- hexadiene, 1, 6octadiene, or mixtures thereof; monocyclic
or polycyclic dienes, for example 1, 4-cyclohexadiene, 5- ethylidene-2-norbornene, 5-methylene-2norbornene, or mixture thereof. The composition of the elastomeric phase is generally as follows :
from 15 mol% to 85 mol% of ethylene; from 85 mol% to 15 mol% of an a-olefin, preferably propylene;
from 0 mol% to 5 mol% of a polyene, preferably a diene.
Preferably, the elastomeric phase consists of an elastomeric copolymer of ethylene and propylene
having the following composition: from 15% by weight to 80% by weight, more preferably from 20%
by weight to 40% by weight, of ethylene; from 20% by weight to 85% by weight, more preferably from
60% by weight to 80% by weight, of propylene, with respect to the total weight of the elastomeric
phase.
The amount of elastomeric phase present in the heterophase copolymer (b) may be determined by
known techniques, for example by extracting the elastomeric (amorphous) phase with a suitable
organic solvent (in particular xylene at 135 C at reflux for 20 min): the amount of elastomeric phase is
calculated as the difference between the initial weight of the sample and the weight of the dried
residue.
The amount of propylene units in the elastomeric phase may be determined by extraction of the
elastomeric phase as described above (for example with xylene at 135 C at reflux for 20 min),
followed by analysis of the dried extract according to known techniques, for example by infrared (IR)
spectroscopy.
Examples of heterophase copolymers (b) which may be used in the present invention and which are
currently commercially available are the products Hifax; or Molen; EP from Basell.
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In the case of the homopolymer or copolymer (c), the "a-olefin" may also be, besides an aliphatic aolefin of
formula CH2=CH-R as defined above, an aromatic a-olefin of formula CH2=CH-R', wherein
R'represents an aryl group having from 6 to 14 carbon atoms. Preferably, the aromatic a-olefin is
selected from : styrene, a-methylstyrene, or mixtures thereof.
Preferably, the homopolymer or copolymer (c) which may be used in the present invention may be
selected from: -propylene homopolymers or copolymer of propylene with ethylene and/or an a-olefin
having from 4 to 12 carbon atoms with an overall content of ethylene and/or a- olefin lower than 10%
by mole; - ethylene homopolymers or copolymers of ethylene with at least one a-olefin having from 4
to 12 carbon atoms; - styrene polymers such as, for example, styrene homopolymers; styrene
homopolymers modified with a natural or synthetic elastomer such as, for example, polybutadiene,
polyisoprene, butyl rubber, ethylene/propylene/diene copolymer (EPDM), ethylene/propylene
copolymers (EPR) natural rubber, epichloridrin; styrene copolymers such as, for example, styrenemethylstyrene copolymer, styrene- isoprene copolymer or styrene-butadiene copolymer; copolymers of ethylene with at least one ethylenically unsaturated ester selected from: alkyl acrylates,
alkyl methacrylates and vinyl carboxylate, wherein the alkyl group, linear or branched, may have from
1 to 8, preferably from 1 to 4, carbon atoms, while the carboxylate group, linear or branched, may
have from 2 to 8, preferably from 2 to 5, carbon atoms ; and wherein the ethylenically unsaturated
ester is generally present in an amount of from 0. 1% to 80% by weight, preferably from 0. 5% to 50%
by weight, with respect to the total weight of the copolymer.
Examples of ethylene homopolymers or copolymers of
ethylene with at least one a-olefin having from 4 to 12 carbon atoms which may be used in the
present invention as homopolymer or copolymer (c) are : low density polyethylene (LDPE), medium
density polyethylene (SDPE), high density polyethylene (HDPE), linear low density polyethylene
(LLDPE), ultra-low density polyethylene (ULDPE), or mixtures thereof.
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Preferably, the copolymers of ethylene with at least one a-olefin having from 4 to 12 carbon atoms
may be selected from: - elastomeric copolymers having the following monomer composition: 35
mol%-90 mol% of ethylene; 10 mol%-65 mol% of an aliphatic a-olefin, preferably propylene; 0 mol%10 mol% of a polyene, preferably a diene, more preferably, 1, 4-hexadiene or 5-ethylene-2norbornene (for example, EPR and EPDM rubbers); - copolymers having the following monomer
composition:
75 mol%-97 mol%, preferably 90 mol%-95 mol%, of ethylene; 3 mol%-25 mol%, preferably 5 mol%10 mol%, of an aliphatic a-olefin ; 0 mol%-5 mol%, preferably 0 mol%-2 mol%, of a polyene,
preferably a diene (for example, ethylene/1-octene copolymers, such as the products Engage of
DuPont-Dow Elastomers).
Examples of styrene polymers which may be used in the present invention are: syndiotactic
polystyrene, atactic polystyrene, isotactic polystyrene, polybutadiene-modified styrene polymer,
styrene-butadiene copolymer, styrene- isoprene copolymer, or mixtures thereof.
With regard to the copolymers of ethylene with at least one ethylenically unsaturated ester, examples
of acrylates or methacrylates are: ethyl acrylate, methyl acrylate, methyl methacrylate, t-butyl acrylate,
n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, or mixtures thereof. Examples of vinyl
carboxylates are: vinyl acetate, vinyl propionate, vinyl butanoate, or
mixtures thereof.
Examples of copolymers of ethylene with at least one ethylenically unsaturated ester which may be
used in the present invention are : ethylene/vinylacetate copolymer (EVA), ethylene/ethylacrylate
copolymer (EEA), ethylene/butylacrylate copolymer (EBA), or mixtures thereof.
When present, the homopolymer or copolymer (c) may be added to the thermoplastic material
according to the present invention generally in an amount not lower than 5% by weight, preferably
not lower than 10% by weight, with respect to the total weight of (a) + (b) + (c).
In order to improve the compatibility between the vulcanized rubber in a subdivided form (a) and the
heterophase copolymer (b), the thermoplastic material according to the present invention further
comprises at least one coupling agent (d).
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It should to be noted that, in the case wherein the heterophase copolymer (b) has an elastomeric
phase made from a copolymer of ethylene with propylene and the amount of propylene in said
copolymer is at least 60% by weight, satisfactory mechanical properties are obtained even in the
absence of said coupling agent (d).
The coupling agent (d) may be selected from those known in the art such as, for example: silane
compounds containing at least one ethylenic unsaturation and at least one hydrolyzable group;
epoxides containing at least one ethylenic unsaturation; monocarboxylic acids or, preferably,
dicarboxylic acids having at least one ethylenic unsaturation, organic titanates, zirconates or
aluminates ; or derivatives thereof, in particular anhydrides or esters.
Examples of silane compounds which are suitable for this purpose are: ymethacryloxypropyltrimethoxysilane, methyltriethoxysilane, methyltris (2-methoxyethoxy) silane,
dimethyldiethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane,
octyltri- ethoxysilane, isobutyltriethoxysilane, isobutyltrimethoxy- silane, or mixtures thereof.
Examples of epoxides containing an ethylenic unsaturation are : glycidyl acrylate, glycidyl
methacrylate, monoglycidyl ester of itaconic acid, glycidyl ester of maleic acid, vinyl glycidyl ether,
allyl glycidyl ether, or mixtures thereof.
Monocarboxylic or dicarboxylic acids, having at least one ethylenic unsaturation, or derivatives
thereof, which may be used as coupling agents are, for example: maleic acid, maleic anhydride,
fumaric acid, citraconic acid, itaconic acid, acrylic acid, methacrylic acid and the like, and
anhydrides or esters derived therefrom, or mixtures thereof. Maleic anhydride is particularly preferred.
Preferably, the coupling agent (d) may be added to the thermoplastic material according to the
present invention in combination with at least one radical initiator (e) so as to graft the coupling agent
directly onto the thermoplastic polymer. An organic peroxide such as, for example, t-butyl
perbenzoate, dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, or mixtures thereof may, for
example, be used as a radical initiator (e).
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The amount of coupling agent (d) which may be added to the thermoplastic material is, generally, of
from 0. 01% by weight to 10% by weight, preferably from 0. 05% by weight to 5% by weight, with
respect to 100 parts by weight of (a) + (b) + (c).
The amount of radical initiator (e) which may be added to the thermoplastic material is, generally, of
from 0. 01% by weight to 1% by weigth, preferably from 0. 05% by weight to 0. 5% by weight, with
respect to 100 parts by weight of (a) + (b) + (c).
The thermoplastic material according to the present invention may further comprises conventional
additives such as lubricants, fillers, pigments, plasticizers, surface-modifying agents, UV absorbers,
antioxidants, hindered amine or amide light stabilizers, or mixtures thereof.
Said thermoplastic material may be prepared by mixing the rubber vulcanized in a subdivided form
(a) and the heterophase copolymer (b) with the other compound optionally present according to
techniques known in the art. The mixing may be carried out, for example, using an open-mill mixer or
an internal mixer of the type with tangential rotors (Banbury) or interlocking rotors (Intermix), or in
continuous mixers of the Ko-Kneader type (Buss) or co-rotating or counter-rotating twin-screw type.
The obtained thermoplastic material may then be extruded and pellettized according to usual
techniques. The pellets may be either packaged for future use or used immediately in a process of
forming a manufactured product. The pellets or blends of the present invention may be formed into
manufactured products according techniques known in the art for thermal processing of
thermoplastic resin compositions. For example, compression molding, vacuum molding, injection
molding, calendering, casting, extrusion, filament winding, laminating, rotational or slush molding,
transfer molding, lay-up or contact molding, stamping, or combinations of these methods, may be
used.
The thermoplastic material according to the present invention may be formed into different kinds of
manufactured products. In particular, the thermoplastic material according to the present invention
may be formed into flooring and footpaths for recreational area ; industrial, sport or safety surfaces;
flooring tiles; anti-static computer mats; rubber mats and sheetings;
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mounting pads; shock absorbers sheetings; sound barriers; membrane protections; airfield runways
or roadway surfaces; shoe soles; carpet underlay; automotive floor mats ; automotive bumpers ;
automotive locary ; automotive door or window seals ; seals ; o-rings ; gaskets ; watering systems ;
pipes or hoses materials ; flower pots ; building blocks; roofing materials; geomembranes; and the
like.
The present invention will be further illustrated below by means of a number of preparation examples,
which are given for purely indicative purposes and without any limitation of this invention.
EXAMPLES 1-8 Preparation of the thermoplastic materials
The thermoplastic materials given in Table 1 were prepared as follows.
All the ingredients were mixed together in an internal mixer (model Pomini PL 1.6) for about 5 min.
As soon as the temperature reached 190 C, a degassing step of 1 minutes was carried out, then the
mixture was discharged.
The obtained mixture was subsequently charged in an open roll mixer operating at a temperature of
150 C in order to obtain a sheet 1 mm thick.
TABLE 1
EXAMPLE 1 2 3 4 5 6 (*) 7(*) 8(*)
Hifax# 70 70 - 40 40 - - CA10A (1)
Hifax# - - 70 - - - - 7320 (1)
Moplen# - - - 30 30 - - YD50G
Moplen# - - - - - 80 60 80
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HP500N (1)
Orevac# - - - - - - - 20 CA100 (1)
Vulcanized 30 30 30 30 30 20 20 20
rubber (2)
Maleic - 2 2 - 2 - 4
anhydride (2)
Peroximon# - 0.2 0.2 - 0.2 - 0.5
DC/SC (2)
comparative ; by weight with respect to the total weight of (a) + (b) + (c) ; (2) : % by weight with
respect to 100 parts by weight of (a) + (b) + (c); HifaxO CA1OA : heterophase copolymer consisting
of: 35% by weight of thermoplastic phase made from a propylene homopolymer ; 65% by weight of
elastomeric phase made from 28% by weight of ethylene and 72% by weight of propylene (Basell) ;
Hifax# 7320: heterophase copolymer consisting of: 35% by weight of thermoplastic phase made
from a propylene homopolymer; 65% by weight elastomeric phase made from
50% by weight of ethylene and 50% by weight of propylene (Basell); Moplens YD50Gs1) :
polypropylene homopolymer (Basell); Moplen# HP500N(1): polypropylene homopolymer (Basell);
Orevac# CA100 (l) : maleic anhydride functionalized polypropylene (0. 9% maleic anhydride)
(Atofina).
Vulcanized rubber' : mechanically ground rubber ( < 0.425 mm (40 mesh) -Somir) ; Peroximon#
DC/SC(2) : dicumyl peroxide (Atofina).
Measurement of the mechanical characteristics
Plates 1 mm thick were formed from the thermoplastic material obtained as disclosed above. The
plates were prepared by moulding for 10 minutes at 180 C and subsequent cooling for 5 minutes to
room temperature.
The plates were used for determining the mechanical characteristics (i. e. stress at break and
elongation at break) according to ASTM standard D638-02a with the Instron instrument and at a
traction speed of 50 mm/min.
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The obtained results are given in Table 2.
TABLE 2
EXAMPLE 1 2 3 4 5 6 (*) 7(*) 8(*)
Elongation 245 396 109 162 238 21.3 20.4 20.9
at break
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(Mpa)
Stres at 9.44 10.15 7.60 10.1 11.4 11 10 7
break
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(MPa)
: comparative.
The data reported in Table 2 show that the thermoplastic material according to the present invention
(Examples 1-5) has improved mechanical properties, in particular improved elongation at break, with
respect to corresponding compositions devoid of the heterophase copolymer (b).Claims:
CLAIMS
1. Thermoplastic material comprising: (a) from 5% by weight to 95% by weight of a vulcanized
rubber in a subdivided form ; (b) from 5% by weight to 95% by weight of at least one heterophase
copolymer comprising a thermoplastic phase made from a propylene homopolymer or copolymer
and an elastomeric phase made from a copolymer of ethylene with an a-olefin ; (c) from 0% by
weight to 90% by weight of at least one a-olefin homopolymer or copolymer different from (b); the
amounts of (a), (b) and (c) being expressed with respect to the total weight of (a) + (b) + (c).
2. Thermoplastic material according to claim 1, wherein the vulcanized rubber in a subdivided form
(a) is present in an amount of from 10% by weight to 60% by weight with respect to the total weight of
(a) + (b) + (c).
3. Thermoplastic material according to claim 1 or 2, wherein the heterophase copolymer (b) is
present in an amount of from 40% by weight to 90% by weight with respect to the total weight of (a) +
(b) + (c).
4. Thermoplastic material according to any one of the preceding claims, wherein the a-olefin
homopolymer or copolymer (c), is present in an amount of from 0% by weight to 50% by weight with
respect to the total weight of (a) + (b) + (c).
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5. Thermoplastic material according to any one of the preceding claims, wherein, the vulcanized
rubber in a subdivided form (a) has a particle size not higher than 10 mm.
6. Thermoplastic material according to claim 5, wherein, the vulcanized rubber in a subdivided form
(a) has a particle size not higher than 5 mm.
7. Thermoplastic material according to any one of claims
1 to 4, wherein the vulcanized rubber in a subdivided form (a) has a particle size not higher than 0.6
mm.
8. Thermoplastic material according to claim 7, wherein the vulcanized rubber in a subdivided form
(a) has a particle size not higher than 0.5 mm.
9. Thermoplastic material according to claim 8, wherein the vulcanized rubber in a subdivided form
(a) has a particle size not higher than 0.2 mm.
10. Thermoplastic material according to any one of the preceding claims, wherein the vulcanized
rubber in a subdivided form (a) comprises at least one diene elastomeric polymer or copolymer of
natural origin or obtained by solution polymerization, emulsion polymerization or gas-phase
polymerization of one or more conjugated diolefins, optionally blended with at least one comonomer
selected from monovinylarenes and/or polar comonomers in an amount of not more than
60% by weight.
11. Thermoplastic material according to claim 10, wherein the diene elastomeric polymer or
copolymer is selected from: cis-1, 4-polyisoprene, 3,4-polyisoprene, polybutadiene, optionally
halogenated isoprene/isobutene copolymers, 1,3- butadiene/acrylonitrile copolymers, styrene/1,3butadiene copolymers, styrene/isoprene/1, 3-butadiene copolymers, styrene/1, 3butadiene/acrylonitrile copolymers, or mixtures thereof.
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12. Thermoplastic material according to any one of the predecing claims, wherein the vulcanized
rubber in a subdivided form (a) comprises at least one elastomeric polymer of one or more
monoolefins with an olefinic comonomer or derivatives thereof.
13. Thermoplastic material according to claim 12, wherein the elastomeric polymer is selected from:
ethylene/propylene copolymers (EPR) or ethylene/propylene/diene copolymers (EPDM);
polyisobutene ; butyl rubbers; halobutyl rubbers, in particular chlorobutyl or bromobutyl rubbers ; or
mixtures thereof.
14. Thermoplastic material according to any one of the preceding claims, wherein the thermoplastic
phase of the heterophase copolymer (b) consists of a propylene homopolymer or a copolymer of
propylene with an olefinic comonomer selected from ethylene and o- olefins other than propylene.
15. Thermoplastic material according to claim 14, wherein the olefinic comonomer is ethylene.
16. Thermoplastic material according to claim 14 or 15, wherein the olefinic comonomer is less than
10 mol% relative to the total number of monomer moles in the thermoplastic phase.
17. Thermoplastic material according to any one of the preceding claims, wherein the elastomeric
phase of the heterophase copolymer (b) is at least 10% by weight relative to the total weight of the
heterophase copolymer.
18. Thermoplastic material according to claim 17, wherein the elastomeric phase of the heterophase
copolymer (b) is at least 40% by weight relative to the total weight of the heterophase copolymer.
19. Thermoplastic material according to claim 18, wherein the elastomeric phase of the heterophase
copolymer (b) is at least 60% by weight relative to the total weight of the heterophase copolymer.
20. Thermoplastic material according to any one of the preceding claims, wherein the elastomeric
phase of the heterophase copolymer (b) consists of an elastomeric copolymer of ethylene with an aolefin and optionally with a polyene.
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21. Thermoplastic material according to claim 20, wherein the a-olefin is propylene.
22. Thermoplastic material according to claim 20 or
21, wherein the polyene is a diene selected from : linear (non-) conjugated diolefins; monocyclic or
polycyclic dienes.
23. Thermoplastic material according to any one of claims
17 to 22, wherein the elastomeric phase has the following composition : from 15 mol% to 85 mol% of
ethylene of an a-olefin ; from 0 mol% to 5 mol% of a diene.
24. Thermoplastic material according to any one of claims
17 to 23, wherein the elastomeric phase consists of an elastomeric copolymer of ethylene and
propylene having the following composition: from 15% by weight to 80% by weight of ethylene; from
20% by weight to 85% by weight of propylene, with respect to the total weight of the elastomeric
phase.
25. Thermoplastic material according to claim 24, wherein the elastomeric phase consists of an
elastomeric copolymer of ethylene and propylene having the following composition: from 20% by
weight to 40% by weight of ethylene; from 60% by weight to 80% by weight of propylene, with
respect to total the weight of the elastomeric phase.
26. Thermoplastic material according to any one of the preceding claims, wherein in the
homopolymer or copolymer (c) the a-olefin is an aliphatic a-olefin of formula CH2=CH-R, wherein R
represents a hydrogen atom, a linear or branched alkyl group containing from
1 to 12 carbon atoms; or an aromatic a-olefin of formula CH2=CH-R', wherein R'represents an aryl
group having from 6 to 14 carbon atoms.
27. Thermoplastic material according to claim 26, wherein the aliphatic a-olefin is selected from:
ethylene,
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propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 4methyl-1- pentene, 4-methyl-l-hexene, 4, 4-dimethyl-l-hexene,
4, 4-dimethyl-1-pentene,-ethyl-1-he : ene, 3-ethyl-1- hexene, 1-octene, 1-decene, 1-dodecene, 1tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, or mixture thereof.
28. Thermoplastic material according to claim 26, wherein the aromatic a-olefin is selected from :
styrene, (X- methylstyrene, or mixtures thereof.
29. Thermoplastic material according to any one of the preceding claims, wherein in the
homopolymer or copolymer (c), the polyene is a conjugated or non- conjugated diene, triene or
tetraene.
30. Thermoplastic material according to any one of the preceding claims, wherein the homopolymer
or copolymer (c) is selected from: -propylene homopolymers or copolymer of propylene with ethylene
and/or an a-olefin having from 4 to
12 carbon atoms with an overall content of ethylene and/or a-olefin lower than 10% by mole; ethylene homopolymers or copolymers of ethylene with at least one a-olefin having from 4 to 12
carbon atoms; - styrene polymers such as styrene homopolymers; styrene homopolymers modified
with a natural or synthetic elastomer such as polybutadiene, polyisoprene, butyl rubber,
ethylene/propylene/diene copolymer (EPDM), ethylene/propylene copolymers (EPR) natural rubber,
epichloridrin; styrene copolymers such as styrene-methylstyrene copolymer, styrene-isoprene
copolymers, or styrene-butadiene copolymer; - copolymers of ethylene with at least one ethylenically
unsaturated ester selected from:
alkyl acrylates, alkyl methacrylates and vinyl carboxylate, wherein the alkyl group, linear or branched,
has from 1 to 8 carbon atoms, while the carboxylate group, linear or branched, has from 2 to 8
carbon atoms; and wherein the ethylenically unsaturated ester is generally present in an amount of
from 0. 1% to 80% by weight with respect to the total weight of the copolymer.
31. Thermoplastic material according to claim 30, wherein the ethylene homopolymers or copolymers
of ethylene with at least one a-olefin having from 4 to 12 carbon atoms are selected from: low density
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polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear
low density polyethylene (LLDPE), ultra-low density polyethylene (ULDPE), or mixtures thereof.
32. Thermoplastic material according to claim 30, wherein the styrene polymers are: syndiotactic
polystyrene, atactic polystyrene, isotactic polystyrene, polybutadiene-modified styrene polymer,
styrene- butadiene copolymer, styrene-isoprene, or mixtures thereof.
33. Thermoplastic material according to claim 30, wherein the copolymers of ethylene with at least
one-olefin having from 4 to 12 carbon atoms are selected from: - elastomeric copolymers having the
following monomer composition: 35 mol%-90 mol% of ethylene;
10 mol%-65 mol% of an aliphatic a-olefin ; 0 mol%10 mol% of a polyene ; copolymers having the following monomer composition: 75 mol%-97 mol% of
ethylene; 3 mol%25 mol% of an aliphatic a-olefin ; 0 mol%-5 mol% of a polyene.
34. Thermoplastic material according to claim 30, wherein the copolymers of ethylene with at least
one
ethylenically unsaturated ester are selected from: ethylene/vinylacetate copolymer (EVA),
ethylene/ethylacrylate copolymer (EEA), ethylene/butylacrylate copolymer (EBA), or mixtures thereof.
35. Thermoplastic material according to any one of the preceding claims, wherein the homopolymer
or copolymer (c) is present in an amount not lower than 5% by weight with respect to the total weight
of (a) + (b) + (c).
36. Thermoplastic material according to claim 35, wherein the homopolymer or copolymer (c) is
present in an amount not lower than 10% by weight with respect to the total weight of (a) + (b) + (c).
37. Thermoplastic material according to any one of the preceding claims, further comprising at least
one coupling agent (d).
38. Thermoplastic material according to claim 37, wherein the coupling agent (d) is selected from:
silane compounds containing at least one ethylenic unsaturation and at least one hydrolyzable group;
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epoxides containing at least one ethylenic unsaturation; monocarboxylic acids or, preferably,
dicarboxylic acids having at least one ethylenic unsaturation, organic titanates, zirconates or
aluminates; or derivatives thereof.
39. Thermoplastic material according to claim 37 or 38, wherein the coupling agent (d) is added in
an amount of from 0. 01% by weight to 10% by weight with respect to 100 parts by weight of (a) + (b)
+ (c).
40. Thermoplastic material according to any one of claims
37 to 39, further comprising a radical initiator (e).
41. Thermoplastic material according to claim 40, wherein the radical initiator is an organic peroxide
selected from: t-butyl perbenzoate, dicumyl peroxide, benzoyl
peroxide, di-t-butyl peroxide, or mixtures thereof.
42. Thermoplastic material according to claim 40 or 41, wherein the radical initiator (e) is present in
an amount of from 0. 01% by weight and 1% by weight, with respect to 100 parts by weight of (a) +
(b) + (c).
43. Manufactured product comprising a thermoplastic material according to any one of the
preceding claims.
44. Manufactured product according to claim 43, said manufactured product being selected from:
industrial, sport or safety surfaces; flooring tiles ; sound barriers; shoe soles; automotive floor mats;
automotive bumpers; automotive locary ; pipes or hoses materials; roofing materials; geomembranes.
386/425
38. WO2004092255 - 28.10.2004
COMPOSITE FORMED ARTICLE COMPRISING VULCANIZED RUBBER AND THERMOPLASTIC
ELASTOMER AND USE THEREOF
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO2004092255
Inventor(s):
IMAI TADASHI [JP] (--)
Applicant(s):
MITSUI CHEMICALS INC [JP] (--); IMAI TADASHI [JP] (--)
IP Class 4 Digits: C08J; C08L; B32B; B60J; B60R; B29C
IP Class:
C8L21/00; C8J5/12; B32B25/04; B60J10/00; B60R13/06; B29C45/14
E Class: B32B25/04; B60J10/00C2; B60J10/00D3; C08J5/12D
Application Number:
WO2004JP04911 (20040405)
Priority Number: JP20030112630 (20030417)
Family: WO2004092255
Cited Document(s):
JP2001270042; JP8269259; WO0181462; JP2003003023; EP1288256;
JP2003155386; JP2003311886
Abstract:
A FORMED VULCANIZED RUBBER ARTICLE (1) WHICH COMPRISES 2 TO 10 WT % OF AN
OLEFINIC RESIN EXHIBITING A CRYSTALLINITY OF 10 % OR MORE AS MEASURED WITH A
DIFFERENTIAL SCANNING CALORIMETER (DSC); AND A COMPOSITE FORMED ARTICLE WHICH
COMPRISES SAID FORMED VULCANIZED RUBBER ARTICLE (1) AND, JOINED THERETO, A
FORMED ARTICLE (2) COMPRISING A THERMOPLASTIC ELASTOMER CONTAINING MORE THAN
10 % OF AN OLEFINIC RESIN EXHIBITING A CRYSTALLINITY OF 10 % OR MORE AS MEASURED
WITH A DIFFERENTIAL SCANNING CALORIMETER (DSC) AND HAVING A GEL CONTENT OF 30
WT % OR LESS. THE FORMED VULCANIZED RUBBER ARTICLE CAN FORM, THROUGH MELT
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ADHESION AND WITHOUT THE USE OF AN ADHESIVE LAYER, A COMPOSITE FORMED ARTICLE
WHICH EXHIBITS SATISFACTORY ADHESION STRENGTH AND CAUSES THE PARENT MATERIAL
FAILURE UPON PEALING. THE ABOVE COMPOSITE FORMED ARTICLE IS ADVANTAGEOUSLY
USED FOR AN INTERIOR OR EXTERIOR MATERIAL FOR AN AUTOMOBILE, IN PARTICULAR, FOR
A WEATHERSTRIP MATERIAL.
388/425
39. WO2004096902 - 11.11.2004
ANTIMICROBIAL PRE-VULCANIZED RUBBER COMPOSITIONS AND ANTIMICROBIAL
VUCLANIZED RUBBER ARTICLES
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO2004096902
Inventor(s):
PATEL BHAWAN [GB] (--); MORRIS DAVID L [GB] (--)
Applicant(s):
MILLIKEN and CO [US] (--); PATEL BHAWAN [GB] (--); MORRIS DAVID L [GB] (--)
IP Class 4 Digits: C08K
IP Class:
C8K
Application Number:
WO2004US09580 (20040326)
Priority Number: US20030423204 (20030425); US20030424024 (20030425); US20030424112
(20030425)
Family: WO2004096902
Abstract:
NON-SILICONE RUBBER ARTICLES THAT EXHIBIT HIGHLY DESIRABLE LONG-TERM EFFECTIVE
ANTIMICROBIAL CHARACTERISTICS ARE PROVIDED. SUCH ARTICLES ARE IN EITHER SOLID OR
BLOWN (FOAM OR SPONGE) STATE (OR COMBINATIONS OF BOTH IN MULTILAYERED FORMS)
AND CAN BE UTILIZED IN A VARIETY OF APPLICATIONS. THIS INVENTION UTILIZES THE
PRESENCE OF NON-SULFUR-BASED CURING SYSTEMS AND AGENTS, SUCH AS BISPHENOLS
AND PEROXIDES, THAT PERMIT VULCANIZATION AND DO NOT IRREVERSIBLY BIND SILVER
IONS THERETO, THEREBY RESULTING IN LONG-TERM ANTIMICROBIAL PERFORMANCE OF THE
RUBBER ARTICLE. THIS INVENTION FURTHER PROVIDES A SIMPLE METHOD OF PRODUCING
SUCH AN ANTIMICROBIAL VULCANIZED NON-SILICONE RUBBER ARTICLE. THIS INVENTION
ALSO ENCOMPASSES CERTAIN NON-SILICONE PRE-VULCANIZED RAW RUBBER
FORMULATIONS MADE FROM AT LEAST A MAJORITY BY WEIGHT OF NON-SILICONE RUBBER
THAT INCLUDES SILVER-BASED COMPONENTS TO PROVIDE HIGHLY DESIRABLE LONG-TERM
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ANTIMICROBIAL CHARACTERISTICS WITHIN THE ULTIMATE CURED RUBBER ARTICLES MADE
THEREFROM.Description:
ANTIMICROBIAL PRE-VULCANIZED RUBBER COMPOSITIONS AND ANTIMICROBIAL
VULCANIZED RUBBER ARTICLES
Field of the Invention
This invention relates to certain non-silicone vulcanized rubber articles made from at least a majority
by weight of non-silicone rubber that includes silver-based compounds to provide highly desirable
long-term antimicrobial characteristics within the cured rubber articles. Such articles are in either
solid or blown (foam or sponge) state (or combinations of both in multilayered forms) and can be
utilized in a variety of different applications.
As silver-based compounds are deleteriously affected by utilization of standard curing agents and
curing accelerators, such as sulfur-based compounds and/or systems, the ability to provide such an
effective antimicrobial vulcanized rubber article is rather difficult. However, this invention
encompasses the presence of different non-sulfur-based curing systems and agents, such as
bisphenol and peroxide, as examples, that permit vulcanization and do not irreversibly bind silver
ions thereto, thereby resulting in long-term antimicrobial performance of the ultimate rubber article
itself. The rubber articles may also comprise fillers and may also include plasticizers to provide
desired characteristics of dimensional stability, stiffness, flexural modulus, tensile strength, abrasion
resistance, elongation, and the like, for the ultimate rubber article, while simultaneously enhancing
the control of antimicrobial efficacy of the rubber article as well. This invention also encompasses a
simple method of producing such an antimicrobial non-silicone vulcanized rubber article.
Furthermore, this invention provides certain non-silicone pre-vulcanized raw rubber formulations
made from at least a majority by weight of non-silicone rubber that includes silver-based components
to provide highly desirable long-term antimicrobial characteristics within the ultimate cured nonsilicone rubber articles made therefrom.
Discussion of the Prior Art
All U. S. Patents listed below are herein entirely incorporated by reference.
There has been a great deal of attention in recent years given to the hazards of bacterial
contamination from potential everyday exposure. Noteworthy examples of such
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concerns include the fatal consequences of food poisoning due to certain strains of EschericEeia
coli being found within undercooked beef in fast food restaurants ; Salmonella enteritidis
contamination causing sicknesses from undercooked and unwashed poultry food products ; and
illnesses and skin infections attributed to Staplzylocoecus aureus, Klebsiellcz piieumoiiiae, yeast
(Candida albicans), and other unicellular organisms. With such an increased consumer interest in
this area, manufacturers have begun introducing antimicrobial agents within various everyday
products and articles. For instance, certain brands of cutting boards, shoe soles, shoe inserts,
medical devices and implements, liquid soaps, etc. , all contain antimicrobial compounds. The most
popular antimicrobial for such articles is triclosan. Although the incorporation of such a compound
within liquid or certain polymeric media has been relatively simple, other substrates, specifically
vulcanized rubber and surfaces thereof, have proven less accessible. Furthermore, such triclosan
additives have proven to be difficult in use or ineffective for certain bacteria. For instance, triclosan
itself migrates easily within and out of certain polymeric substrates and/or matrices (and thus is not
very durable), lacks thermal stability (and thus readily leaches out of rubber and like materials at
higher temperatures), and does not provide a wide range of bacterial kill (for instance, does not
exhibit any kill for Pseudomonas ae ^ugiraosa).
Antimicrobial rubber formulations are certainly highly desired for the production of vulcanized rubber
articles and compositions to provide not only antibacterial benefits, but also antifungal, antimildew,
antistaining, and odor control properties. Rubber articles are utilized in many different applications,
from automobiles (hoses, tires, bumpers, etc. ), to household items (toys, sink washers, gaskets,
appliances, floor mats, door mats, carpeted rubber mats, gloves, and the like), and other areas in
which bacterial growth is a potential problem. Thus, there remains a long-felt need to provide an
effective, durable, reliable antimicrobial pre-vulcanized rubber formulation which will provide such
long-tenn antimicrobial, antifungal, etc. , effects within the final vulcanized article. Unfortunately, such
a highly desired antimicrobial rubber formulation and/or vulcanized article containing silverbased
antimicrobial agents has heretofore not been provided by the pertinent prior art.
The closest art includes Japanese Patent Application 1997-342076 which discloses the production
of unvulcanized rubber formulations and articles exhibiting antibacterial
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properties due to the presence of silver complexes. Such formulations are formed through high
temperature kneading in an oxygen-free atmosphere and are used as parts in a water disinfection
system. Again, no vulcanized rubber is taught or obtained within or through this disclosure.
Antimicrobial rubber bands have been taught in Japanese Patent Application 1997- 140034 in
vulcanized form with silver antimicrobials therein. However, such compounds are rather limited in use
and the vulcanization step must include a sulfur curing agent to effectuate the final vulcanized
arrangement of the subject rubber. Such sulfur curing agents have a remarkably deleterious effect
on certain silver-based antimicrobials such that the sulfur reacts with the silver ion to from silver
sulfide, thereby rendering it ineffective as a bactericide. As such, the utilization of such specific
rubber band formulations for and within large-scale antimicrobial articles is basically unworkable.
Certain types of antimicrobial peroxide-catalyst vulcanized rubber formulations have been produced
in the past; however, such peroxide-cured rubbers are all silicone-based. It is well understood and
accepted that silicone rubbers cannot be vulcanized by typical sulfurbased catalysts. Thus, the
antimicrobial rubber formulations of Japanese Patent Applications 1997-026273 and 1995-065149 as
well as U. S. Pat. No. 5,466, 726 are standard vulcanized silicone rubber formulations and articles
which also include certain antimicrobial compounds.
Additionally, some types of rubber, such as butyl and its derivative chlorobutyl rubber, have a
tendency to de-polymerize when cured with peroxide based curing systems.
Furthermore, rubber latexes (non-vulcanized) comprising antimicrobials have been disclosed (U. S.
Pat. No. 5,736, 591, for example), as have floor mats having silver-based antimicrobials incorporated
within pile fiber components. These floor mats have nonantimicrobial rubber backings cured through
peroxide-catalyzed vulcanization to protect the pile fiber antimicrobial compounds from attack by
any sulfur compounds (as in Japanese Patent Applications 1993-3555168 and 1995-38991). Again,
however, to date there have been no disclosures or suggestions of producing a vulcanized nonsilicone rubber formulation or article exhibiting excellent antimicrobial properties through the longterm effective utilization of silver-based antibacterial compounds. This invention fills such a void.
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Object of the Invention
It is therefore an object of this invention to provide an antimicrobial vulcanized substantially nonsilicone rubber article exhibiting sufficient antimicrobial activity and structural integrity to withstand
repeated use without losing an appreciable level of either antimicrobial power or modulus strength.
Another object of the invention is to provide an antimicrobial vulcanized substantially non-silicone
rubber article comprising silver-based antimicrobial compounds which include curing agents that do
not deleteriously affect the antimicrobial activity of the finished vulcanized article (and thus is
essentially free from sulfur-based curing agents and accelerators).
A further object of this invention is to provide an antimicrobial substantially nonsilicone prevulcanized raw rubber formulation that ultimately provides a vulcanized nonsilicone rubber article of
sufficient antimicrobial activity and structural integrity to withstand repeated use without losing an
appreciable level of either antimicrobial efficiency or modulus strength. Another object of this
invention is to ultimately provide an antimicrobial nonsilicone pre-vulcanized rubber formulation
comprising silver-based antimicrobial compounds which include curing agents and curing
accelerators which do not deleteriously effect the antimicrobial activity of the ultimate vulcanized
non-silicone rubber article (and thus is essentially free from sulfur-based curing agents and
accelerators).
Detailed Description of the Invention
The term"dimensionally stable"is intended to encompass a vulcanized rubber article that is
structurally able to be handled without disintegrating into smaller portions. Thus, the article must
exhibit some degree of structural integrity and, being a rubber, a certain degree of flexural modulus.
Such a specific antimicrobial vulcanized non-silicone rubber article has not been taught nor fairly
suggested within the rubber industry or prior art. As noted above, the avoidance of sulfur-based
curing agents and accelerators to any appreciable degree thus permits the retention of silver
antimicrobials within the final product in amounts sufficient to provide long-lasting log kill rates for
Staphylococcus aureus, Klebsiella pneunioniae, Pseudomonas aeruginosa, and Escherichia coli, at
the very least. Furthermore, due primarily
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to high costs, non-sulfur curing agents have not been prevalent within vulcanized rubber
formulations and articles. As such, there has been no teaching or fair suggestion of coupling nonsulfur curing agents (and most preferably peroxide and/or bisphenol curing agents) with silver-based
antimicrobial agents within pre-vulcanized non-silicone rubber formulations to form effectively
antimicrobial vulcanized rubber articles.
Additionally, certain fillers and oils (such as silica, carbon black, magnesium oxide, calcium
hydroxide, stearates as fillers, and phthalate and paraffinic oils) are generally, although not
necessarily, required to provide both flexural modulus and structural integrity to vulcanized rubber
articles. The rubber component alone generally does not exhibit proper dimensional stability without
such additives. The presence of such additives may also provide the ability to control silver-ion
release at the target article surface. Without intending to be bound to any specific scientific theory, it
appears that such fillers as silica and such oils as paraffinic oil (as some examples), act in such a
way as to draw moisture into the article which then transports silver ions from within the article to the
surface. In such a situation, then, the rubber article may exhibit enhanced silver release resulting in
higher log kill rates for certain bacteria due to the presence of larger amounts of available surface
silver ions.
Other hydrophobic fillers, such as pigments (for example, carbon black) and calcium carbonate
appear to work in the opposite manner by keeping water out of the target article and prevent silverion migration to the article surface. Thus, the reduction of such silver-ion availability decreases the
antibacterial efficacy of the rubber article. In effect, then, the actual antibacterial efficacy of the entire
rubber article can be controlled through the presence of certain amounts of such generally required
fillers and oils (some hydrophilic antistatic agents also appear to act in the same manner as silica as
well).
As a result, the necessary filler and/or oil constituents required to provide dimensional resiliency
and/or flexural modulus (and thus actual usefulness) of the finished article serve a dual purpose
heretofore unrecognized within the rubber industry. Rubber articles can be produced with specific
end-uses in mind depending upon the duration of antimicrobial activity desired through the addition
of specific amounts of such additives. Again, such a targeted duration antimicrobial vulcanized
article and the benefits thereof have heretofore
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been unknown and unrecognized within the rubber industry. These rubber components are thus
hereinafter referred to as"silver ion release control additives".
The term rubber is intended to cover any standard rubber which must be vulcanized to provide a
dimensionally stable rubber article. The specific types of rubber are listed below and have been
utilized previously within the rubber industry for a variety of applications and are generally well known
and taught throughout the prior art. The inventive rubber formulations and cured articles may also
possess a chemical plasticizer which aids in the breakdown period of the elastomer during
compounding and processing (and provides flexural modulus properties to the finished article) as
well as fillers required for reinforcement (e. g. calcium carbonate, carbon black, silica, and clays).
Optionally, to form a blown (foam or sponge) rubber article, a blowing agent may be added to the
inventive formulation.
The rubber component or components of the inventive rubber formulation and cured article is
therefore selected from the group consisting of nitrile rubber [such as acrylonitrile- butadiene rubber
(NBR) ], styrene-butadiene rubber (SBR), natural rubber, chloroprene rubber, polychloroprene
rubber, ethylene propylene rubber, ethylene propylene diene monomer (EPDM) rubber,
fluoroelastomer rubber, polyurethane rubber, butyl rubber, halogenated butyl rubber [such as
chlorobutyl rubber and bromobutyl rubber], isoprene rubber, epichlorohydrin rubber, polyacrylate
rubber, chlorinated polyethylene rubber, hydrogenated NBR, carboxylated NBR, polybutadiene
rubber, and the like.
Other types of rubber may also be mixed with the base rubber type in order to provide different
strengths, flexibilities, or other properties. Such other components may then include, without
limitation, nitrile rubber [such as acrylonitrile-butadiene rubber (NBR)], styrene-butadiene rubber
(SBR), natural rubber, chloroprene rubber, polychloroprene rubber, ethylene propylene rubber,
ethylene propylene diene monomer (EPDM) rubber, fluoroelastomer rubber, polyurethane rubber,
butyl rubber, butyl rubber, halogenated butyl rubber [such as chlorobutyl rubber and bromobutyl
rubber], isoprene rubber, epichlorohydrin rubber, polyacrylate rubber, chlorinated polyethylene
rubber, hydrogenated NBR, carboxylated NBR, polybutadiene rubber, and the like.
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More specifically, the term fluoroelastomer rubber is intended to cover any standard rubber which
possesses at least a majority by weight of fluoroelastomer rubber and which must be vulcanized to
provide a dimensionally stable rubber article. Fluoroelastomer rubber is generically referred to as
FKM polymer according to the nomenclature noted in ASTM D1418 and is often classified by its
fluorine content. For example, many standard fluoroelastomer rubbers are available having a fluorine
content of 66%, 68%, and 70%, although many specialty grades are now available with fluorine
content in a range of between about 60% and about 75%.
Similarly, the term epichlorohydrin rubber is intended to cover any standard rubber which possesses
at least a majority by weight of epichlorohydrin rubber and which must be vulcanized to provide a
dimensionally stable rubber article. The term polybutadiene rubber is intended to cover any standard
rubber which possesses at least a majority by weight of polybutadiene rubber and which must be
vulcanized to provide a dimensionally stable rubber article. The term polychloroprene rubber is
intended to cover any standard rubber which possesses at least a majority by weight of
polychloroprene rubber and which must be vulcanized to provide a dimensionally stable rubber
article. The term styrene butadiene rubber is intended to cover any standard rubber which
possesses at least a majority by weight of styrene butadiene rubber and which must be vulcanized to
provide a dimensionally stable rubber article.
Although the presence of silicone rubber is discouraged within the inventive formulation, there
remains the possibility of adding certain low amounts of such specific unvulcanized rubber
components without adversely affecting the overall antimicrobial rubber formulation itself. Thus, up to
25% by total weight of the formulation may be silicone rubber; however, the vast majority of the
rubber formulation must be non-silicone rubber.
Furthermore, the non-silicone rubber portion must not possess an appreciable amount of sulfurbased curing agent or residue (in the finished article) and thus must be vulcanized through curing
with primarily non-sulfur-based compounds (such as resins, bisphenols, peroxides, and/or metal
oxides, for example). The rubber component is present in an amount of from about 10 to about 1,000
parts of the entire composition, more preferably from about 50 to about 500 parts, and most
preferably from about 70 to about 200 parts of the entire
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composition. Thus, with a total number of parts between about 100 and about 2,000 parts
throughout the target vulcanized rubber article, the rubber constitutes from about 25 to about 70% of
the percentage by parts of the entire article. The remainder comprises additives such as fillers, oils,
curing agents, the desired antimicrobial agents, optional blowing agents, and the like (as discussed
more thoroughly below).
It is intended that vulcanization or other processing of these non-silicone rubbers be performed in an
environment that is inexpensive to provide and should be undertaken in an oxygen-rich atmosphere
(as opposed to an anaerobic environment which is generally difficult to provide). As mentioned
previously, these non-silicone rubbers have been utilized previously within the rubber industry for a
variety of applications and are generally well known and taught throughout the prior art. Such
inventive rubber articles may also possess a chemical plasticizer which aids in the breakdown period
of the elastomer during compounding and processing (and provides flexural modulus properties to
the finished article) as well as fillers required for reinforcement (e. g. calcium carbonate, carbon
black, magnesium oxide, calcium hydroxide, silica, and clays). Optionally, to form a blown (foam or
sponge) rubber article, a blowing agent may be added to the inventive formulation.
The antimicrobial agent of the inventive raw rubber formulation may be of any standard silver-based
compounds. Such compounds, in contrast with organic types, such as triclosan, for example, do not
exhibit low thermal stability and remain within the target matrix or substrate at different temperatures.
Thus, such an antimicrobial is more easily controlled, as discussed above, for surface release as
desired. Such agents include, without limitation, silver salts, silver oxides, elemental silver, and, most
preferably, ion exchange, glass, and/or zeolite compounds. Of even greater preference are silverbased ion exchange compounds for this purpose due to the low levels of discoloration and
enhanced durability in the final product provided by such compounds, the efficacy provided to the
final formulation with such a compound, and the ease of manufacture permitted with such specific
compounds.
Thus, the antimicrobial agent of this invention may be any type which imparts the desired log kill
rates to Staplzylococcus aureus, Klebsiella pneurraofziae, Escherichia coli, and Pseudomonas
aeruginosa, as merely representative organisms. Furthermore, such antimicrobial compounds must
be able to withstand elevated processing temperatures for
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successful incorporation within the target non-sulfur (bisphenol and/or peroxide, for example) cured
rubber articles. Again, such antimicrobial agents comprise, preferably, silvercontaining ion exchange,
glass, and/or zeolite compounds. Most preferably, such a compound is a silver-based ion-exchange
compound and particularly does not include any added organic bactericide compounds (thereby not
permitting a release of volatile organic compounds into the atmosphere during processing at high
temperatures, etc.).
The preferred silver-based ion exchange material is an antimicrobial silver zirconium phosphate
available from Milliken & Company, under the trade name ALPHASANO. Such compounds are
available in different silver ion concentrations as well as mixtures with zinc oxide. Thus, different
compounds of from about 0.01 to 15% of silver ion concentration, more preferably from about 3 to
about 10%, and most preferably amounts of about 10% by total amount of components (e. g. of the
total amount of silver ions and zirconium phosphate) are possible. Other potentially preferred silvercontaining solid inorganic antimicrobials in this invention are silver-substituted zeolite available from
Sinanen under the tradename ZEOMICt, or a silver-substituted glass available from Ishizuka Glass
under the tradename IONPUREOO, which may be utilized either in addition to or as a substitute for
the preferred species. Other possible compounds, again without limitation, are silver-based materials
such as MICROFREEO, available from DuPont, as well as JMACO, available from Johnson Mathey.
Generally, such an antimicrobial compound is added to a rubber formulation in an amount of from
about 0.1 to 10% by total weight of the particular total rubber formulation, preferably from about 0.1
to about 5%, more preferably from about 0.1 to about 2%, and most preferably about 2%.
Furthermore, with regard to silver-based inorganic antimicrobial materials, these particular
antimicrobial rubber articles are shown to be particularly suitable for the desired high levels of
efficacy and durability required of such articles. It has been found that certain silver-based ion
exchange compounds, such as ALPHASAN RO brand antimicrobials available from Milliken &
Company, (U. S. Patent 5926238, U. S. Patent 5441717, U. S. Patent 5698229 to Toagosei Chemical
Industry Inc.), exhibit impressive bio-efficacy. After a period of time,
alternative antimicrobial compounds (e. g. triclosan, microchek, OBPA, Zn-omadine) initially suffer
from decomposition under the high processing temperatures, which is followed by depletion of the
biocide through leaching into the surrounding environment and finally through depleted bactericidal
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activity. However, silver-containing ion exchange, glass, and/or zeolite compounds do not suffer
from these shortcomings. Such antimicrobial agents exhibit high temperature stability ( > 1000 C), do
not leach into the environment and provide substantial amounts of the oligodynamic silver ion to
provide for the desired extensive durability.
In testing the antimicrobial rubber articles for effectiveness, it has been generally observed that a
relationship exists between silver elution values (quantity of silver ions released at the surface of the
article) and antimicrobial efficacy against certain organisms.
For example, silver elution values greater than about 1.5 ng/cm2 silver generally result in the
maximum log kill reduction against Klebsiella pneumoniae and Staphylococcus aureus.
Accordingly, it is generally desirable that the inventive antimicrobial articles should exhibit an
acceptable log kill rate after 24 hours for S. aureus when tested in accordance with the ATCC Test
Method 6538 and for K. pneumoniae when tested in accordance with ATCC Test Method 4352. Such
an acceptable level log kill rate is tested for S. aureus or K pneumoniae of at least 0.1 increase over
baseline. Alternatively, an acceptable level will exist if the log kill rate is greater than the log kill rate
for non-treated (i. e. , no solid inorganic antimicrobial added) rubber articles (such as about 0.5 log
kill rate increase over control, antimicrobial-free vulcanized rubber article). Prerferably, these log kill
rate baseline increases are at least 0.3 and 0.3, respectively for S. aureus and K. pneumoniae; more
preferably these log kill rates are 0.5 and 0.5, respectively; and most preferably these are 1.0 and 1.0,
respectively. Of course, the high end of such log kill rates are much higher than the baseline, on the
magnitude of 5.0 (99.999% kill rate). Any rate in between is thus, of course, acceptable as well.
However, log kill rates which are negative in number are also acceptable for this invention as long as
such measurements are better than that recorded for correlated nontreated rubber articles. In such
an instance, the antimicrobial material present within the rubber article at least exhibits a hindrance
to microbe growth. Furthermore, such rubber
articles should exhibit log kill rates of the same degree for other types of bacteria, such as,
Pseudofyaonas aeruginosa and Escherichia coli.
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It is also contemplated within this invention that the finished inventive articles will provide antifungal
benefits as well as antibacterial characteristics. Such versatility is rare among antibacterial
compounds; however, without intending to be limited to any particular scientific theory, it appears
that the silver ions, and particularly the silver ions present at the article surface in great abundance,
provide excellent antifungal properties. For example, it is believed that this inventive rubber
formulation should provide fungal kill durability of at least 15 sequential days for such organisms as
Aspergillus niger and possibly for mixtures of fungi including A. niger ATCC 6275, Paecilomyces
variotii ATCC 18502, and Trichoderma virens ATCC 9645, when tested according to Test Method
ISO 846. In order to provide a greater array of potential antifungal benefits, other compounds may be
incorporated within the target pre-vulcanized rubber formulation (and subsequent article), such as
zinc oxide, as one example.
Of great importance to the effectiveness of the inventive articles in terms of antimicrobial and
antifungal activity is the omission of deleterious amounts of sulfur-based curing agents, accelerators,
and additives which bind silver (such as barium sulfate filler which may be used in non-black FKM
rubber) from the rubber article. As noted above, it is believed, without intending to be bound to any
specific scientific theory, that sulfur reacts with the preferred silver-based antimicrobials and
irreversibly binds the silver ions (as silver sulfides, for example) within the rubber composition and/or
article itself. As such, the resultant silver sulfides, etc. , are ineffective as antimicrobial agents and
their presence renders the final product antimicrobially inactive. Thus, it has been necessary to
produce a vulcanized rubber article lacking any appreciable amount of sulfur curing agents,
accelerators, and additives therein. It should be appreciated that the term"appreciable
amount"permits a small amount to be present. It has been found that, as a molar ratio, a 1: 1 ratio
(and above) between sulfur molar presence and silver molar presence results in a clear loss of
antimicrobial activity within the desired ultimate vulcanized article. However, greater molar amounts
of silver in relation to sulfur provide at least some antimicrobial properties to the desired article. A
molar ratio range of from about 0.25 : 1 to about 0.000000001 : 1 of sulfur to
silver ions is thus at least acceptable. The primary curing agent, however, must be of non- sulfur
nature (such as a bisphenol or peroxide-based compound) in order to provide the desired
antimicrobial activity for the subject rubber.
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Although bisphenol and peroxide curing agents have been utilized for vulcanization of rubber
previously, such different types of curing agents are not widely utilized as suitable vulcanization
catalysts for rubber for a number of reasons. Foremost, such curing agents are much more costly
than standard sulfur-based agents and the utilization of such bisphenols and/or peroxides, and the
like, as a replacement for the sulfur-based compounds have been rather limited to mostly siliconebased rubbers or, at the very least, non-antibacterial rubber articles. However, due to the problems
associated with antimicrobial activity when such compounds are reacted with sulfur-based curing
agents, alternatives to such sulfur-based cured articles was to permit utilization of such effective
antimicrobial compounds within raw and vulcanized rubber for long-tenn high log kill rate effects.
Thus, although non-sulfurbased compounds are not readily utilized within the non-silicone industry as
vulcanization curing agents, utilization of such curing agents was necessary to provide an effective,
ultimate antimicrobial vulcanized rubber article.
Surprisingly, it has now been found that the inventive rubber articles listed above are available
without such sulfur-based curing agents in any appreciable amounts; most importantly, with the
introduction of certain additives, the structural integrity and/or flexural modulus of the rubber
formulation is improved to an acceptable level, and the efficacy of the antimicrobial components can
be controlled simultaneously.
Thus, the curing agent present within the raw rubber formulation to be vulcanized to form the
inventive article must be at least a majority, and preferably at least about 75% by weight of a nonsulfur-based curing agent. As discussed above, traditional sulfur and sulfurbased catalysts will not
work with the inventive antimicrobial formulations due to chemical reactions between the sulfur atoms
and the biocidal Ag+ ion. However, non-sulfur-based catalysts provide effective curing for the
inventive raw rubber formulations, such as, for example and without limitation, bisphenols, peroxides,
and other oxide curing systems.
Peroxides include, for example, organic peroxides such as dicumyl peroxide, 2,5-bis (t-
butylperoxy) -2, 5-dimethylhexane, di- (t-butyl-peroxy-isopropyl) benzene, di- (t-butyl-peroxytrimethyl) -cyclohexane, and the like, as well as inorganic peroxides. Oxides include, for example,
zinc oxide, and the like. Some curing agents, bisphenol for example, may already be incorporated in
the unvulcanized rubber during the manufacturing process. These curing agents should generally be
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present in amount of from about 0.5 to about 100 parts per hundred parts of rubber (pphr), more
preferably from about 1 to about 50 pphr, and most preferably from about 1 to about 10 pphr, all
either as one curing agent alone, or as the combination of any number of different types of curing
agents.
Other additives present within the inventive vulcanized rubber article may include any of the
aforementioned silver ion release control additives, accelerators, accelerator activators,
antidegradants, softeners, abrasives, colorants, flame retardants, homogenizing agents, internal
lubricants, and deodorants. Such components should be present, if at all, in rather low amounts, of
from about 0.1 to about 50 pphr.
It has further been contemplated that a substantial increase in the antibacterial and antifungal
efficacy may be provided upon washing the finished inventive article. Abrading the surface of such
an article may permit increases in such characteristics due to an increase in Ag+ release; however,
industrial laundering of certain rubber products (mats, and the like) may provide improved
antimicrobial, antifungal, etc. , efficacy through a simple washing. In fact, such an increase may
steadily improve with greater numbers of consistent washes such that a rubber article, as first
vulcanized, may exhibit lower overall antibacterial and antifungal activity than one that has been
washed one, two, three, and up to at least 20 times (in a standard industrial rotary washing machine).
Such a surprising benefit may permit utilization of such rubber articles as floor coverings (mats, as
one example, such'as those with carpeted portions or those which are rubber alone; particularly
foamed rubber mats for antifatigue properties and reduced specific gravity so as to reduce the
chances of machinery damage during such industrial rotary launderings and drings), and other
articles which can be easily washed within standard laundry machines.
Furthermore, as alluded to above, friction with the subject rubber article surface can remove very
slight layers of rubber from the article surface thereby permitting"fresh"silver-
comprising crystallites at the surface to act as desired in their antibacterial and/or antifungal
capacities. Basically, then, the inventive article produced from the inventive raw rubber formulation
exhibits an even dispersion of antimicrobial particles throughout the entire rubber article. Such an
even dispersion of the biocide throughout the rubber article thus provides a reservoir of fresh
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crystallites containing the biocidal metallic ion. As layers of the rubber are worn and abraded away,
antimicrobial particles containing untapped silver ions become available.
The preferred non-sulfur cured rubber articles of this invention containing the antimicrobial agent
can be processed into rubber articles which exhibit excellent antimicrobial qualities as well as
antimicrobial efficiency throughout the rubber article's lifetime. Examples of other such rubber
articles encompassed within this invention include, but are not limited to hard rubber mats, static
dissipative rubber mats, anti-fatigue rubber mats, rubber mats which include a face fiber, rubber link
mats, rubber seals and gaskets, rubber medical goods, rubber gloves, rubber medical devices,
rubber conveyor belts, rubber belts and rubber wheels used in food processing, rubber clothing,
rubber shoes, rubber boots, rubber tubing, and rubber automotive fuel hoses. Such inventive
formulations may also be incorporated into a multilayered rubber article in which the antimicrobial
agent can be incorporated into any surface layer and still provide the desired antimicrobial efficiency.
Of particular interest is the formation of multilayered rubber articles wherein at least one of such
rubber layers exhibit the desired antimicrobial activity and thus is made from an inventive non-sulfur
cured, non-silicone containing rubber article. Such layered articles may be adhered together through
co-vulcanization, gluing, and the like. Furthermore, layers of other types of materials may be placed
between the rubber layers as well to provide, as one non-limiting property, better structural stability
to the desired multilayered article.
The non-limiting, preferred embodiments of these rubber formulations and articles are discussed in
greater detail below.
Description of the Preferred Embodiments Inventive Raw Rubber Formulations
(INVENTIVE) BASE FORMULATION 1 Component Amount Fluoroelastomer Rubber (Dai-el G751
from Daikin Industries, Ltd.) * 100 parts N990 Black (CABOT carbon black filler) 20 pphr Magnesium
oxide 3 pphr Calcium hydroxide 6 pphr Antimicrobial (ALPHAS RC2000 from Milliken & Company)
2% by weight *Bisphenol added prior to compounding.
(INVENTIVE) BASE FORMULATION 2 Component Amount Fluoroelastomer Rubber (Dai-el G902
from Daikin Industries, Ltd. ) 100 parts N990 Black (CABOT carbon black filler) 20 pphr di- (tert-
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butyl-peroxy-isopropyl) benzene (14/40 from AKM) 2 pphr di- (tert-butyl-peroxy-trimethyl)
cyclohexane (29/40 from AKM) 2 pphr Antimicrobial (ALPHASANO RC2000 from Milliken & Company)
2% by weight (INVENTIVE) BASE FORMULATION 3 Component Amount Epichlorohydrin Rubber
(Hydrin T3000LL from Zeon Chemicals) 100 parts FEF N550 (CABOT carbon black filler) 50 pphr
Mistron Vapour (Magnesium silicate filler) 20 pphr Di-isodecyl phthalate (DIDP) (plasticizer oil from
AKM) 10 pphr Calcium Oxide 3 pphr Dicumyl Peroxide/40ke 3 pphr Aflux 54 (pentaerythritol
tetrastearate process aid from Rhein-chemie) 2 pphr Diphenyl Guanadiene (curative) 1 pphr TMQ
(antioxidant) 0.5 pphr Stearic Acid (available from AILS) 0.25 pphr Antimicrobial (ALPHASANO
RC2000 from Milliken & Company) 2% by weight (INVENTIVE) BASE FORMULATION 4 Component
Amount Polybutadiene Rubber (BR1220 from Enichem) 100 parts Mistron Vapour 20 pphr FEF N550
Black 20 pphr Paraffinic oil 10 pphr Zinc Oxide Active (available from Bayer) 5 pphr Aflux 54 2 pphr
di- (tert-butyl-peroxy-isopropyl) benzene (14/40 from AI (M) 1.5 pphr di-(tert-butyl-peroxy-trimethyl)
cyclohexane (29/40 from AKM) 1.5 pphr Stearic Acid 1 pphr CPL (antioxidant from AILS) 1 pphr
Antimicrobial (ALPHASAN RC2000 from Milliken & Company) 2% by weight
(INVENTIVE) BASE FORMULATION 5 Component Amount Polychloroprene Rubber (Neoprene WRT
from Dupont) 100 parts Mistron Vapour 30 pphr FEF N550 Black 30 pphr DIDP 15 pphr Magnesium
Oxide (available from AI (M) 4 pphr Aflux 54 2 pphr 14/40 2 pphr 29/40 2 pphr Stearic Acid 1 pphr
Antimicrobial (ALPHASAN RC2000 from Milliken & Company) 2% by weight (INVENTIVE) BASE
FORMULATION 6 Component Amount Styrene Butadiene Rubber (SBR 1502 from Enichem) 100
parts Mistron Vapour (magnesium silicate filler from Luzanac) 25 pphr FEF N550 (Cabot carbon
black filler) 25 pphr Brisol 300 (available from AKM) 20 pphr Zinc Oxide Active (available from Bayer)
5 pphr Aflux 54 (pentaerythritol tetrastearate process aid from Rhein-chemie) 2 pphr di- (tert-butylperoxy-isopropyl) benzene (14/40 from AKM) 2 pphr di-(tert-butyl-peroxy-trimethyl) cyclohexane
(29/40 from AI (M) 2 pphr CPL (antioxidant available from AI (M) 1 pphr Stearic Acid (available from
AI (M) 0.5 pphr Antimicrobial (ALPHASAN RC2000 from Milliken & Company) 5% by weight
These inventive raw rubber formulations were created using ALPHASAN RC2000 (available from
Milliken & Company), a silver ion-exchange zirconium phosphate salt, exhibiting 10% Ag+
concentration and including AgxNayHzZr2 (P04) 3, where x+y+z=l, as other components (% by
weight).
The compounding of ingredients within each formulation can be carried out in an open mill, an
internal mixer, or an extruder where intensive mixing within the polymer matrix of each component
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will take place. During the mixing operation, the control of temperature rise, due to high shear
incorporation of the ingredients, is crucial to ensure that pre- vulcanization (scorch) does not take
place during processing. Generally, a maximum temperature of 120 C is reached on single stage
(pass) mixing through an internal mixer. The compounds can be further processed after mixing into
specific forms to allow adequate
presentation for manufacturing into products. This could be calendering, extrusion,
granulation/pelletization, strip form, fabrication and preforming into specific shaped blanks.
The vulcanization of the compounds can be in the form of molding (compression, transfer, injection),
continuous extrusion (LCM, UHF [where pennissible], autoclave and hot air), and coatings. The
vulcanization (cure) temperatures can range from 150 C to 250 C. In this specific situation, the
rubber articles were calendared into rough mat structures and then subjected to vulcanization under
high temperature and pressure.
Testing of Vulcanized Rubber Articles-Base Formulation 1
Silver-ion extraction (or, silver elution) values were determined for the inventive rubber article. The
rubber article was immersed in an aqueous salt extraction solution (sodium phosphate) for 24 hours;
the extract was then analyzed by inductively coupled plasma measurements for a measurement of
available silver removed from the article surface.
Base Formulation 1 exhibited 1.049 ppb/cm2 and 16.570 ng/cm2 surface available Ag+ ions.
Thus, the inventive article exhibited controlled release of silver ions. As previously discussed, silver
elution at a rate of greater than 1.5 ng/cm2 is believed to provide maximum log kill reduction after 24
hours for S. aureus when tested in accordance with ATCC Test Method 6538 and for K. pneumoniae
when tested in accordance with ATCC Test Method 4352. Accordingly, it is believed that the silver
elution results shown above provide highly desirable long-term antimicrobial characteristics within
the cured rubber article.
Testing of Vulcanized Rubber Articles-Base Formulations 3,4 and 5
Experimental Tables 1 and 2 list the antibacterial activity of these inventive and comparative samples.
The antimicrobial tests followed were ATCC Test Method 6538 for Staphylococcus aureus and ATCC
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Test Method 4352 for Klebsiella pneumoniae. The internal control was created using a
polypropylene plaque.
EXPERIMENTAL TABLE 1
Antimicrobial Performance of Inventive Rubber Articles for
Staphvlococcus aureus and Klebsiella praeumoniae log kill reduction vs. internal control SampleID
RubberID S. aureus S. pneumoniae Rubber Formulation 3 Epichlorohydrin 2.98 3.52 Rubber
Formulation 4 Polybutadiene 2.98 3.04 Rubber Formulation 5 Polychloroprene 2.58 3.52 Max. Log Kill
2. 98 3.52
Thus, the inventive formulations provided inventive vulcanized rubber articles that exhibited
improved antimicrobial activity over the same formulations without any antimicrobial compounds
present. Specifically, the epichlorohydrin and polybutadiene rubber articles reached maximum log
kill reduction for S. aureus, while the epichlorohydrin and polychloroprene reached maximum log kill
reduction for K. pneumoniae.
The inventive articles with Formulations 3 and 4 above were also tested for silver ion elution at the
articles'surface both before and after exposure of the articles to repeated standard industrial wash
cycles (35 lb. loads). To measure eluted silver, the target articles were immersed in an aqueous salt
extraction solution (sodium phosphate) for 24 hours ; the extract was then analyzed by inductively
coupled plasma measurements for a measurement of available silver removed from the
articles'surface. The results are as follows:
EXPERIMENTAL TABLE 2
Available Surface Silver Ions of Inventive Rubber Articles Sample ID Rubber Type wash cycles ppb
of bio-available Ag+/cm2 Formulation 3 Epichlorohydrin 0 wash 0.126 Formulation 3
Epichlorohydrin 20 wash 0.155 Formulation 4 Polybutadiene 0 wash 0.887 Formulation 4
Polybutadiene 20 wash 2.836
Thus, surprisingly, the amount of available silver ions increased dramatically not just from the article's
finished state, but also up to (and beyond) twenty standard washes. Such an unexpected benefit
thus provides the user with an antimicrobial structure, such as a mat, that actually increases its
antimicrobial efficacy during use.
406/425
Testing of Vulcanized Rubber Articles-Base Formulation 6
The antimicrobial tests followed were ATCC Test Method 6538 for Staphylococcus aureus and ATCC
Test Method 4352 for Klebsiella praeumoraiae. The internal control was created using a
polypropylene plaque. Base Formulation 6 exhibited a log kill reduction of 2.98 for S. aureus and
3.52 for K. pneumoniae. The maximum log kill reduction values obtained were 2. 98 for S. aureus and
3.52 for K pneu7noniae.
Thus, the inventive formulation provided an inventive vulcanized rubber article that exhibited
improved antimicrobial activity over the same formulation without any antimicrobial compounds
present. Specifically, the SBR article achieved maximum log kill reduction for both S. aureus and K
pneumoniae.
The inventive article was also tested for silver ion elution at the article surface both before and after
exposure of the article to repeated standard industrial wash cycles (35 lb. loads). To measure eluted
silver, the target article was immersed in an aqueous salt extraction solution (sodium phosphate) for
24 hours; the extract was then analyzed by inductively coupled plasma measurements for a
measurement of available silver removed from the article surface. The results are as follows:
EXPERIMENTAL TABLE 3
Available Surface Silver Ions of Inventive Rubber Article Sample ID Rubber Type wash cycles ppb of
bio-available Ag+/cm2 Formulation 6 SBR 0 wash 0. 356 Formulation 6 SBR 20 wash 1.571
Thus, surprisingly, the amount of available silver ions increased dramatically not just from the article's
finished state, but also up to (and beyond) twenty standard washes. Such an unexpected benefit
thus provides the user with an antimicrobial structure, such as a mat, that actually increases its
antimicrobial efficacy during use.
Having described the invention in detail, it is obvious that one skilled in the art will be able to make
variations and modifications thereto without departing from the scope of the present invention.
Accordingly, the scope of the present invention should be determined only by the claims appended
hereto.Claims:
407/425
CLAIMS 1. A dimensionally stable vulcanized rubber article comprising at least a majority of
fluoroelastomer rubber and at least one silver-based antimicrobial compound, wherein said rubber
article exhibits silver elution at a rate of at least 1.5 ng/cm2 after 24 hours exposure at room
temperature, and wherein said article optionally comprises at least one silver ion release control
additive.
2. The rubber article of Claim 1 wherein said article exhibits silver elution at a rate of at least 2.5
ng/cm2 after 24 hours exposure at room temperature.
3. The rubber article of Claim 1 wherein said silver-based antimicrobial compound is selected from
the group consisting of elemental silver, silver oxides, silver salts, silver ion exchange compounds,
silver zeolites, silver glasses, and any mixtures thereof.
4. The rubber article of Claim 1 wherein said at least one silver ion control release additive is present.
5. The rubber article of Claim 4 wherein said at least one silver ion control release additive is
selected from the group consisting of fillers, oils, pigments, salts, antistatic agents, and any mixtures
thereof.
6. The rubber article of Claim 5 wherein said at least one silver ion control release additive is a filler
selected from the group consisting of carbon black, magnesium oxide, calcium hydroxide, and any
mixtures thereof.
7. A pre-vulcanized rubber formulation comprising at least one rubber constituent, the majority of
which must be fluoroelastomer rubber, at least one silver-based antimicrobial compound and at least
one curing compound, wherein all of said curing compound present within said formulation does not
include an appreciable amount of sulfur-based compounds,
and wherein said rubber formulation optionally comprises at least at least one silver ion release
control additive.
408/425
8. The rubber formulation of Claim 7 wherein said silver-based antimicrobial compound is selected
from the group consisting of elemental silver, silver oxides, silver salts, silver ion exchange
compounds, silver zeolites, silver glasses, and any mixtures thereof.
9. The rubber formulation of Claim 7 wherein said curing compound comprises a majority amount by
weight of at least one bisphenol.
10. The rubber formulation of Claim 7 wherein said curing compound comprises a majority amount
by weight of at least one peroxide.
11. The rubber formulation of Claim 7 wherein said at least one silver ion control release additive is
present.
12. The rubber formulation of Claim 11 where said at least one silver ion control release additive is
selected from the group consisting of fillers, oils, pigments, salts, antistatic agents, and any mixtures
thereof.
13. The rubber formulation of Claim 12 wherein said at least one silver ion control release additive is
a filler selected from the group consisting of carbon black, magnesium oxide, calcium hydroxide,
and any mixtures thereof.
14. A method of producing a rubber article exhibiting long-lasting, regenerable antimicrobial
characteristics, comprising the steps of compounding together the unvulcanized rubber formulation
of Claim 7, molding said rubber formulation into a preselected shape, and vulcanizing said rubber
formulation under high pressure and exposure to high temperature.
15. A rubber composition comprising at least one fluoroelastomer rubber component, at least one
bisphenol curing agent, and at least one silver-based antimicrobial agent, and optionally comprising
at least one silver ion release control additive.
409/425
16. A rubber composition comprising at least one fluoroelastomer rubber component, at least one
peroxide curing agent, at least one silver-based antimicrobial agent, and optionally comprising at
least one silver ion release control additive.
17. A dimensionally stable vulcanized rubber article comprising at least a majority of a rubber
constituent selected from the group consisting of epichlorohydrin rubber, polybutadiene rubber,
polychloroprene rubber, and any mixtures thereof, and at least one silver-based antimicrobial
compound, wherein said rubber article exhibits log kill rates in accordance with ATCC Test Method
6538 for Staphylococcus aureus and ATCC Test Method 43 52 for Klebsiella pneutnoniae of at least
1.0 each after 24 hours exposure at room temperature, and wherein said article optionally comprises
at least one silver ion release control additive, and at least one antifungal additive other than said
silver-based antimicrobial compound.
18. The rubber article of Claim 17 wherein said article exhibits log kill rates for Staphylococcus
aureus and Klebsiella p7 ? eumoniae of at least 2.0 each after 24 hours exposure at room
temperature.
19. The rubber article of Claim 17 wherein said silver-based antimicrobial compound is selected from
the group consisting of elemental silver, silver oxides, silver salts, silver ion exchange compounds,
silver zeolites, silver glasses, and any mixtures thereof.
20. The rubber article of Claim 17 wherein said at least one silver ion control release additive is
present.
21. The rubber article of Claim 17 wherein said antifungal additive other than said silver-based
antimicrobial compound is present.
22. The rubber article of Claim 20 wherein said at least one silver ion control release additive is
selected from the group consisting of fillers, oils, pigments, salts, antistatic agents, and any mixtures
thereof.
410/425
23. The rubber article of Claim 22 wherein said at least one silver ion control release additive is a
hydrophilic filler selected from the group consisting of silica, stearates, and any mixtures thereof.
24. The rubber article of Claim 22 further comprising at least one hydrophilic oil selected from the
group consisting of paraffinic oil, phthalate oil, and any mixtures thereof.
25. An antimicrobial vulcanized rubber article comprising at least a majority of a rubber constituent
selected from the group consisting of epichlorohydrin rubber, polybutadiene rubber, and any
mixtures thereof wherein said article exhibits an increase in silver elution when measured first for
silver elution after initial article production as compared with subsequent measurement for silver
elution after said article is exposed to twenty standard launderings within a standard industrial rotary
washing machine.
26. A pre-vulcanized rubber formulation comprising at least one rubber constituent, the majority of
which is selected from the group consisting of epichlorohydrin rubber, polybutadiene rubber,
polychloroprene rubber, and any mixture thereof; at least one silver- based antimicrobial compound;
and at least one curing compound, wherein all of said curing compound present within said
formulation does not include an appreciable amount of sulfur- based compounds, and wherein said
rubber formulation optionally comprises at least one blowing agent, at least one silver ion release
control additive, and at least one antifungal additive other than said silver-based antimicrobial
compound.
27. The rubber formulation of Claim 26 wherein said silver-based antimicrobial
compound is selected from the group consisting of elemental silver, silver oxides, silver salts, silver
ion exchange compounds, silver zeolites, silver glasses, and any mixtures thereof.
28. The rubber formulation of Claim 26 wherein said silver-based antimicrobial compound is selected
from the group consisting of elemental silver, silver oxides, silver salts, silver ion exchange
compounds, silver zeolites, silver glasses, and any mixtures thereof.
29. The rubber formulation of Claim 26, wherein said curing compound comprises a majority amount
by weight of at least one peroxide.
411/425
30. The rubber formulation of Claim 29, wherein said peroxide is an organic peroxide.
31. The rubber formulation of Claim 26 wherein said at least one blowing agent is present.
32. The rubber formulation of Claim 26 wherein said at least one silver ion control release additive is
present.
33. The rubber formulation of Claim 26 wherein said antifungal additive other than said silver-based
antimicrobial compound is present.
34. A method of producing a rubber article exhibiting long-lasting, regenerable antimicrobial
characteristics, comprising the steps of compounding together the unvulcanized rubber formulation
of Claim 26, molding said rubber formulation into a preselected shape, and vulcanizing said rubber
formulation under high pressure and exposure to high temperature.
35. A rubber composition comprising at least one rubber component, the majority of which is
selected from the group consisting of epichlorohydrin rubber, polybutadiene rubber polychloroprene
rubber, and any mixture thereof ; at least one
peroxide curing agent; at least one silver-based antimicrobial agent; and optionally comprising at
least one blowing agent, at least one silver ion release control additive, and at least one antifungal
additive other than said silver-based antimicrobial compound.
36. A dimensionally stable vulcanized rubber article comprising at least a majority of styrene
butadiene rubber and at least one silver-based antimicrobial compound, wherein said rubber article
exhibits log kill rates in accordance with ATCC Test Method 6538 for Staphylococcus aureus and
ATCC Test Method 4352 for lRlebsiella pneumoniae of at least 1.0 each after 24 hours exposure at
room temperature, and wherein said article optionally comprises at least one silver ion release
control additive, and at least one antifungal additive other than said silver-based antimicrobial
compound.
412/425
37. The rubber article of Claim 36 wherein said article exhibits log kill rates for Staplaylococcus
aureus and Klebsiella pneumoniae of at least 2.0 each after 24 hours exposure at room temperature.
38. The rubber article of Claim 36 wherein said silver-based antimicrobial compound is selected from
the group consisting of elemental silver, silver oxides, silver salts, silver ion exchange compounds,
silver zeolites, silver glasses, and any mixtures thereof.
39. The rubber article of Claim 36 wherein said at least one silver ion control release additive is
present.
40. The rubber article of Claim 36 wherein said antifungal additive other than said silver-based
antimicrobial compound is present.
41. The rubber article of Claim 39 wherein said at least one silver ion control release additive is
selected from the group consisting of fillers, oils, pigments, salts, antistatic agents, and any mixtures
thereof.
42. The rubber article of Claim 41 wherein said at least one silver ion control release additive is a
hydrophilic filler selected from the group consisting of silica, stearates, and any mixtures thereof.
43. The rubber article of Claim 41 further comprising at least one hydrophilic oil selected from the
group consisting of paraffinic oil, phthalate oil, and any mixtures thereof.
44. An antimicrobial vulcanized rubber article comprising at least a majority of styrene butadiene
rubber wherein said article exhibits an increase in silver elution when measured first for silver elution
after initial article production as compared with subsequent measurement for silver elution after said
article is exposed to twenty standard launderings within a standard industrial rotary washing machine.
45. A pre-vulcanized rubber formulation comprising at least one rubber constituent, the majority of
which is styrene butadiene rubber ; at least one silver-based antimicrobial compound; and at least
one curing compound, wherein all of said curing compound present within said formulation does not
413/425
include an appreciable amount of sulfur-based compounds, and wherein said rubber formulation
optionally comprises at least one blowing agent, at least one silver ion release control additive, and
at least one antifungal additive other than said silver-based antimicrobial compound.
46. The rubber formulation of Claim 45 wherein said silver-based antimicrobial compound is selected
from the group consisting of elemental silver, silver oxides, silver salts, silver ion exchange
compounds, silver zeolites, silver glasses, and any mixtures thereof.
47. The rubber formulation of Claim 45, wherein said curing compound comprises a majority amount
by weight of at least one peroxide.
48. The rubber formulation of Claim 47, wherein said peroxide is an organic peroxide.
49. The rubber formulation of Claim 45 wherein said at least one blowing agent is present.
50. The rubber formulation of Claim 45 wherein said at least one silver ion control release additive is
present.
51. The rubber formulation of Claim 45 wherein said antifungal additive other than said silver-based
antimicrobial compound is present.
52. A method of producing a rubber article exhibiting long-lasting, regenerable antimicrobial
characteristics, comprising the steps of compounding together the unvulcanized rubber formulation
of Claim 45, molding said rubber formulation into a preselected shape, and vulcanizing said rubber
formulation under high pressure and exposure to high temperature.
53. A rubber composition comprising at least one rubber component, wherein said rubber
constituent is styrene butadiene rubber; at least one peroxide curing agent; at least one silver-based
antimicrobial agent; and optionally comprising at least one blowing agent, at least one silver ion
release control additive, and at least one antifungal additive other than said silver-based
antimicrobial compound.
414/425
40. WO2004108819 - 16.12.2004
VULCANIZED FLUORINE RUBBER AND CUSHIONING MATERIAL FOR HEAT PRESS CONTAINING
SAME
URL EPO = http://v3.espacenet.com/textdoc?F=3&CY=ep&LG=en&IDX=WO2004108819
Inventor(s):
YOSHIDA AKIRA [JP] (--)
Applicant(s):
YAMAUCHI CORP [JP] (--); YOSHIDA AKIRA [JP] (--)
IP Class 4 Digits: C08K; C08L; B29C
IP Class:
C8L27/12; C8K3/22; C8K5/13; B29C43/02
E Class: C08L27/12+B2
Application Number:
WO2004JP06843 (20040520)
Priority Number: JP20030164179 (20030609)
Family: WO2004108819
Equivalent:
JP2005002148
Cited Document(s):
JP2000052369; JP2002144484; JP4268357; JP7053821; JP7026052
Abstract:
A VULCANIZED FLUORINE RUBBER IS DISCLOSED WHICH IS OBTAINED BY VULCANIZING 100
PARTS BY MASS OF A MIXTURE, WHEREIN A MATERIAL FLUORINE RUBBER (A) WHICH IS
BLENDED IN ADVANCE WITH AN APPROPRIATE AMOUNT OF A VULCANIZING AGENT AND A
MATERIAL FLUORINE RUBBER (B) WHICH IS NOT BLENDED WITH ANY VULCANIZING AGENT
ARE MIXED AT A RATIO FROM 8/2 TO 3/7, AND A COMPOSITION COMPOSED OF 1-10 PARTS BY
MASS OF AN ACID ACCEPTOR AND 0-5 PARTS BY MASS OF OTHER COMPOUNDING
INGREDIENTS WHICH ARE BLENDED IF NECESSARY. THE NUMBER-AVERAGE MOLECULAR
415/425
WEIGHT OF THE MATERIAL FLUORINE RUBBER (A) AND MATERIAL FLUORINE RUBBER (B) IS
FROM 3.5 X 10<4> TO 2.0 X 10<5>.
416/425
ผลการวิเคราะห์ ข้อมูลสิทธิบัตร
เกี่ยวกับ “Vulcanized
1. GENERAL
- Request Information
Name:
VulcanizedRubber
- Request Parameters
Search 0
Name: unknown
Title: Vulcanized Rubber
Result:
1302
- Request Results
Inventors: 1938
Applicants: 810
IP Class 4 digits:
IP Class Full: 704
E Class:
463
97
- Patent information repartition
Groups:
0
417/425
Rubber”
2. DETAILS
2.1. Inventors (Top 8)
2.2. Applicants (Top 8)
418/425
2.3. IP Class 4 Digits (Top 10)
B29C
SHAPING OR JOINING OF PLASTICS; SHAPING OF SUBSTANCES IN A
PLASTIC STATE, IN GENERAL; AFTER- TREATMENT OF THE SHAPED
PRODUCTS, e.g. REPAIRING (working in the manner of metal B23; grinding,
polishing B24; cutting B26D, B26F; making preforms B29B 11/00)
B29H
B32B
LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR
NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
B60C
VEHICLE TYRES (manufacture, repairing B29); TYRE INFLATION; TYRE
CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN
GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES (testing of
tyres G01M 17/02)
C08C
TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
419/425
C08F
MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY
INVOLVING CARBON-TO-CARBON UNSATURATED BONDS (production of
liquid hydrocarbon mixtures from lower carbon number hydrocarbons, e.g. by
oligomerisation, C10G 50/00)
C08J
WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTERTREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G
(mechanical aspects B29; layered products, manufacture thereof B32B;
treatment of macromolecular material specially adapted to enhance its filling
properties in mortars, concrete or artificial stone C04B 16/04, C04B 18/20, C04B
20/00; treatment of textiles D06)
C08K
USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES
AS COMPOUNDING INGREDIENTS (pesticides, herbicides A01N;
pharmaceuticals, cosmetics A61K; explosives C06B; paints, inks, varnishes,
dyes, polishes, adhesives C09; lubricants C10M; detergents C11D; artificial
filaments or fibres D01F; textile treating compositions D06)
C08L
COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (pesticides,
herbicides A01N; pharmaceuticals, cosmetics A61K; explosives C06B;
compositions based on polymerisable monomers C08F, C08G; paints, inks,
varnishes, dyes, polishes, adhesives C09; lubricants C10M; detergents C11D;
artificial filaments or fibres D01F; textile treating compositions D06)
C09J
ADHESIVES; ADHESIVE PROCESSES IN GENERAL (NON-MECHANICAL PART);
ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF
MATERIALS AS ADHESIVES (surgical adhesives A61L 24/00; processes for
applying liquids or other fluent materials to surfaces in general B05D; adhesives
on the basis of non specified organic macromolecular compounds used as
bonding agents in layered products B32B; organic macromolecular compounds
C08; production of multi-layer textile fabrics D06M 17/00)
2.4. IP Class 7 digits (Top 9)
420/425
C8J1
C8J3
C8J5
C8J7
C8K3
C8K5
C8L2
C8L9
2.5. IP Class Full (Top 8)
421/425
B29C
SHAPING OR JOINING OF PLASTICS; SHAPING OF SUBSTANCES IN A
PLASTIC STATE, IN GENERAL; AFTER- TREATMENT OF THE SHAPED
PRODUCTS, e.g. REPAIRING (working in the manner of metal B23; grinding,
polishing B24; cutting B26D, B26F; making preforms B29B 11/00)
C8J3
C8J5
C8K3
C8L2
C8L9
2.6. E Class (Top 5)
422/425
B60C
VEHICLE TYRES (manufacture, repairing B29); TYRE INFLATION; TYRE
CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN
GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES (testing of
tyres G01M 17/02)
C08K
USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES
AS COMPOUNDING INGREDIENTS (pesticides, herbicides A01N;
pharmaceuticals, cosmetics A61K; explosives C06B; paints, inks, varnishes,
dyes, polishes, adhesives C09; lubricants C10M; detergents C11D; artificial
filaments or fibres D01F; textile treating compositions D06)
C08L
COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (pesticides,
herbicides A01N; pharmaceuticals, cosmetics A61K; explosives C06B;
compositions based on polymerisable monomers C08F, C08G; paints, inks,
varnishes, dyes, polishes, adhesives C09; lubricants C10M; detergents C11D;
artificial filaments or fibres D01F; textile treating compositions D06)
423/425
3. STATISTICS
3.1. Inventors / Applicants (Top 4)
KAWASAKI MASAAKI ( -- )
ZAKHAROV NIKOLAJ D ( -- )
others: 02 ( -- )
DATTA RABINDRA NATH ( NL )
NIKITIN YURIJ N ( -- )
AOSHIMA MASASHI ( JP )
OGREL ADOLF M ( -- )
WATANABE KIYOSHI ( -- )
NAKAHAMA HIDENARI ( -- )
OREKHOV SERGEJ V ( -- )
DE HOOG ARIE JACOB ( NL )
HONDA TOSHIO ( -- )
others: 01 ( -- )
MITSUI CHEMICALS INC ( -- )
YAROSLAVSKIJ POLT INST [SU] ( -- )
SUMITOMO CHEM CO LTD ( -- )
AKZO NOBEL NV ( NL )
VNII TEKHN UGLERODA [SU] ( -- )
Sumitomo Chemical Company Limited ( JP )
VOLGOGRADSKY POLITEKH INST [SU] ( -- )
HITACHI CABLE ( -- )
MITSUI CHEMICALS INC ( -- )
VNII TEKHN UGLERODA [SU] ( -- )
AKZO NOBEL NV ( NL )
BRIDGESTONE CORP ( -- )
NOK CORP ( -- )
15
11
11
9
7
7
7
7
7
7
7
7
7
C08J
C08L
C08L
C08L
C08K
C08L
C08J
B29C
C08K
B29H
C08K
C08L
31
30
29
23
19
19
18
17
15
14
12
12
3.2. Inventors / IP Class 4 digits (Top 10)
others: 01 ( -- )
others: 02 ( -- )
others: 01 ( -- )
KAWASAKI MASAAKI ( -- )
others: 02 ( -- )
others: 03 ( -- )
KAWASAKI MASAAKI ( -- )
others: 01 ( -- )
others: 01 ( -- )
others: 01 ( -- )
KAWASAKI MASAAKI ( -- )
ZAKHAROV NIKOLAJ D ( -- )
424/425
3.3. Applicants / IP Class 4 digits (Top 9)
SUMITOMO CHEM CO LTD ( -- )
SUMITOMO CHEM CO LTD ( -- )
BRIDGESTONE CORP ( -- )
BRIDGESTONE CORP ( -- )
YAROSLAVSKIJ POLT INST [SU] ( -- )
MITSUI CHEMICALS INC ( -- )
NOK CORP ( -- )
BRIDGESTONE CORP ( -- )
MITSUI PETROCHEM IND LTD ( -- )
MITSUI CHEMICALS INC ( -- )
BRIDGESTONE CORP ( -- )
BRIDGESTONE CORP ( -- )
YAROSLAVSKIJ POLT INST [SU] ( -- )
MITSUI PETROCHEM IND LTD ( -- )
The Goodyear Tire and Rubber Company
( US )
C08L
C08K
C08J
C08L
C08L
C08L
C08J
B60C
C08L
C08J
B29C
C08K
C08K
C08J
C08K
35
30
19
18
15
14
14
12
12
12
11
11
10
10
10
.
จัดทำโดย ปรำโมทย์ ธรรมรัตน์ และ พรวิ สำข์ บุญยงค์
หน่วย สสวพ. สำนักงำนกองทุนสนับสนุนกำรวิ จยั
สถำบันค้นคว้ำและพัฒนำผลิ ตภัณฑ์อำหำร มหำวิ ทยำลัยเกษตรศำสตร์
วิ เครำะห์และรวบรวมข้อมูลด้วยโปรแกรม Matheo Patent
425/425