ORGANISATION AFRICAINE DE LA PROPRIETE INTELLECTUELLE
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Inter. CI. N° 16745
A41G 3/00; A41G 5/00;
C08L 67/02; D01F 6/92
C08L 63/00
FASCICULE DE BREVET D’INVENTION
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Numéro de dépôt : 1201400080
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Date de dépôt : 25/02/2014
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Priorité(s) :
JP n° JP2013-196848 du 24/09/2013
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Titulaire(s) :
KANEKA CORPORATION,
3-18, Nakanoshima 2-chome, Kita-ku,
OSAKA-SHI, Osaka 530-8288 (JP)
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Inventeur(s) :
HASHIMOTO, Tomomichi (JP)
YORIZANE, Mika (JP)
HIGAMI, Tomokazu (JP)
KAWAMURA, Kohei (JP)
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Mandataire :
Cabinet Spoor & Fisher Inc. Ngwafor
& Partners, Blvd. du 20 Mai,
Immeuble Centre Commercial de
l'Hôtel Hilton, 2è Etage, Porte 208A,
B.P. 8211, YAOUNDE (CM).
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Délivré le : 30/11/2014
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Publié le : 14.12.2015
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Titre : Polyester-based fiber for artificial hair, method for producing the same, and bundle for hair and
hair ornament product including the same.
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Abrégé :
The present invention provides a polyester-based fiber for
artificial hair having high flame retardance and also having
favorable heat resistance, a method for producing the
polyester-based fiber for artificial hair, and a fiber bundle for
hair and a hair ornament product including the polyesterbased fiber for artificial hair. A polyester-based fiber for
artificial hair of the present invention includes a polyester
resin and a brominated epoxy flame retardant. The
polyester resin is polyalkylene terephthalate and/or a
copolymerized
polyester
containing
polyalkylene
terephthalate as the main component. The polyester resin
has an intrinsic viscosity of 0.3 to 0.5. A method for
producing the polyester-based fiber for artificial hair
preferably includes a step of reducing the intrinsic viscosity
of the polyester resin using a sugar alcohol and/or a
bisphenol-based compound containing two or more
hydroxyl groups in the molecule and having a melting point
of 80°C or more and a boiling point of 260°C or more.
O.A.P.I. – B.P. 887, YAOUNDE (Cameroun) – Tel. (237) 22 20 57 00– Fax: (237) 22 20 57 27– Site web: http:/www.oapi.int – Email: oapi@oapi.int
16745
POLYESTER-BASED FIBER FOR ARTIFICIAL HAIR, METHOD FOR PRODUCING THE SAME, AND
FIBER BUNDLE FOR HAIR AND HAIR ORNAMENT PRODUCT INCLUDING THE SAME
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a polyester-based fiber for artificial hair capable of being used as an
alternative to human hair, a method for producing the polyester-based fiber for artificial hair, and a fiber bundle
for hair and a hair ornament product including the polyester-based fiber for artificial hair. Specifically, the
present invention relates to a polyester-based fiber for artificial hair having high flame retardance and also
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having favorable heat resistance, a method for producing the polyester-based fiber for artificial hair, and a fiber
bundle for hair and a hair ornament product induding the polyester-based fiber for artificial hair.
2. Description of Related Art
In hair ornament products such as a hairpiece, a hair wig, crepe hair, a hair band, and doll hair,
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human hair has been conventionally used. However, in recent years, it is becoming difficult to obtain human
hair, and the importance of fibers for artificial hair, instead of human hair, is increasing. Modacrylic fibers have
often been used as fiber materials for artificial hair because of their flame retardance, but the heat resistance of
the modacrylic fibers has been insufficient. Thus, it has been proposed to use polyester-based fibers
containing polyethylene terephthalate as the main component, which has excellent heat resistance, as fibers
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for artificial hair. In addition, since polyester-based fibers for use as fibers for artificial hair are also required to
have flame retardance for the sake of safety, various attempts have been made to impart flame retardance to
the polyester-based fibers. For example, JP 200542234A, JP 2005-264397A, WO 2005/056894, and JP
2007-131982A have proposed flame retardant polyester-based fibers obtained by incorporating a brominated
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epoxy flame retardant into a polyester-based fiber.
SUMMARY OF THE INVENTION
However, although the flame retardance of the flame retardant polyester-based fibers disdosed in JP
2005-42234A, JP 2005-264397A, WO 2005/056894, and JP 2007-131982A has been improved by
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incorporating a brominated epoxy flame retardant into the fibers, the heat resistance of the fibers has been
insufficient in some cases. Thus, the fibers were easily caused to shrink by heat, and there have been cases
where the fibers were softened or crimped during setting with a hair iron at a high temperature.
In order to solve the above-described conventional problems, the present invention provides a
polyester-based fiber for artificial hair having high flame retardance and also having favorable heat resistance,
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a method for producing the polyester-based fiber for artificial hair, and a fiber bundle for hair and a hair
ornament product induding the polyester-based fiber for artificial hair.
The present invention relates to a polyester-based fiber for artificial hair including a polyester resin
and a brominated epoxy flame retardant, wherein the polyester resin is at least one resin selected from the
group consisting of polyalkylene terephthalate and copolymerized polyesters containing polyalkylene
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terephthalate as the main component, and the polyester resin has an intrinsic viscosity of 0.3 to 0.5.
In the polyester-based fiber for artificial hair, it is preferable that the brominated epoxy flame retardant
has a number-average molecular weight of 1000 to 20000. Moreover, it is preferable that the polyester-based
fiber for artificial hair includes 0.1 parts by weight or more and less than 5 parts by weight of a
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viscosity-reducing agent with respect to 100 parts by weight of the polyester resin, the viscosity-reducing agent
being a sugar alcohol and/or a bisphenol-based compound containing two or more hydroxyl groups in the
molecule and having a melting point of 80°C or more and a boiling point of 260°C or more.
The present invention also relates to a method for producing the polyester-based fiber for artificial hair,
the method induding a step of reducing the intrinsic viscosity of a polyester resin using a viscosity-reducing
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agent, the viscosity-reducing agent being a sugar alcohol and/or a bisphenol-based compound containing two
or more hydroxyl groups in the molecule and having a melting point of 80°C or more and a boiling point of
260°C or more.
The present invention also relates to a fiber bundle for hair including the polyester-based fiber for
artificial hair and at least one fiber selected from the group consisting of human hair, animal hair, polyvinyl
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chloride-based fibers, modacrylic fibers, polyamide-based fibers, polyolefin-based fibers, regenerated protein
fibers, and other polyester-based fibers,
The present invention also relates to a hair ornament product including the polyester-based fiber for
artificial hair.
The hair ornament product may further include at least one fiber selected from the group consisting
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of human hair, animal hair, polyvinyl chloride-based fibers, modacrylic fibers, polyamide-based fibers,
polyolefin-based fibers, regenerated protein fibers, and other polyester-based fibers.
According to the present invention, in the polyester-based fiber for artificial hair including the polyester
resin and the brominated epoxy flame retardant, the intrinsic viscosity of the polyester resin is set to a range of
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0.3 to 0.5. Thus, the present invention provides a polyester-based fiber for artificial hair, a fiber bundle for hair,
and a hair ornament product that have high flame retardance and also have favorable heat resistance.
DETAILED DESCRIPTION OF THE INVENTION
The inventors of the present invention have conducted numerous studies to solve the above
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problems and found that when, in a polyester-based fiber for artificial hair including a polyester resin and a
bronninated epoxy flame retardant, the intrinsic viscosity (IV) of the polyester resin is set within a range of 0.3 to
0.5, heat resistance is improved while high flame retardance is maintained. Thus, the present invention was
accomplished. Moreover, the inventors of the present invention found that using a brominated epoxy flame
retardant having a low number-average molecular weight, in particular, a brominated epoxy flame retardant
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having a number-average molecular weight of 1000 to 20000, in addition to setting the intrinsic viscosity of the
polyester resin within a range of 0.3 to 0.5 improves color development while maintaining high flame
retardance and heat resistance. Furthermore, the inventors of the present invention found that a sugar
alcohol and/or a bisphenol-based compound containing two or more hydroxyl groups in the molecule and
having a melting point of 80°C or more and a boiling point of 260°C or more serves as a viscosity-reducing
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agent and has an effect of reducing the intrinsic viscosity of the polyester resin. When a polyester resin
having an intrinsic viscosity of more than 0.5 is used as a raw material polyester resin, and an adjustment is
made so that the intrinsic viscosity of the polyester resin after being processed into fiber is within a range of 0.3
to 0.5 by reducing the intrinsic viscosity of the raw material polyester resin by using a sugar alcohol and/or a
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bisphenol-based compound containing two or more hydroxyl groups in the molecule and having a melting
point of 80°C or more and a boiling point of 260°C or more, in particular, by incorporating 0.1 parts by weight or
more and less than 5 parts by weight of the sugar alcohol and/or the bisphenol-based compound containing
two or more hydroxyl groups in the molecule and having a melting point of 80°C or more and a boiling point of
260°C or more with respect to 100 parts by weight of the polyester resin, a polyester-based fiber for artificial
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hair having good spinning properties and excellent flame retardance, heat resistance, and color development
can be produced.
The polyester-based fiber for artificial hair of the present invention is composed of a polyester resin
composition including a polyester resin, a brominated epoxy flame retardant, and the like.
The polyester resin is at least one resin selected from the group consisting of polyalkylene
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terephthalate and copolymerized polyesters containing polyalkylene terephthalate as the main component.
The polyalkylene terephthalate is not particularly limited and may be, for example, polyethylene terephthalate,
polypropylene terephthalate, polybutyiene terephthalate, or polycyclohexane dimethylene terephthalate. The
copolymerized polyesters containing polyalkylene terephthalate as the main component are not particularly
limited and may be, for example, copolymerized polyesters containing polyalkylene terephthalate such as
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polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or polycyclohexane
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dimethylene terephthalate as the main component and other copolymerizable components. In the present
invention, the term "main component" means a component that is contained in an amount of 80 mol°/0 or more.
Thus, the "copolymerized polyesters containing polyalkylene terephthalate as the main component" refers to
the copolymerized polyesters containing 80 mol% or more of polyalkylene terephthalate.
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Examples of the other oopolymerizable components indude the following: polycarboxylic adds such
as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic add, paraphenylenedicarboxylic acid, trimellitic
acid, pyromellitic add, succinic add, glutaric add, adipic add, suberic add, azelaic acid, sebacic add, and
dodecanedioic add, and their derivatives; dicarboxylic adds including a sulfonic add salt such as
5-sodiumsulfoisophthalic add and dihydroxyethyl 5-sodiumsulfoisophthalate, and their derivatives;
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1,2-propanediol; 1,3-propanediol; 1,4-butanediol; 1,6-hexanediol; neopentyl glycol;
1,4-cyclohexanedimethanol; diethylene glycol; polyethylene glycol; trimethylolpropane; pentaerythritol;
4-hydroxybenzoic acid; and c-caprolactone.
Specific examples of the copolymerized polyesters containing polyalkylene terephthalate as the main
component include copolymerized polyesters obtained by copolymerization of polyethylene terephthalate as
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the main component with one compound selected from the group consisting of ethylene glycol ether of
bisphenol A, 1,4-cyclohexanedimethanol, isophthalic acid, and dihydroxyethyl 5-sodiumsulfoisophthalate.
The polyalkylene terephthalate and/or the copolymerized polyesters containing polyalkylene
terephthalate as the main component may be used alone or in a combination of two or more. In particular, it
is preferable that polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, a
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copolymerized polyester obtained by copolymerization of polyethylene terephthalate as the main component
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with ethylene glycol ether of bisphenol A, a copolymerized polyester obtained by copolymerization of
polyethylene terephthalate as the main component with 1,4-cyclohexanedimethanol, a copolymerized
polyester obtained by copolymerization of polyethylene terephthalate as the main component with isophthalic
add, and a copolymerized polyester obtained by copolymerization of polyethylene terephthalate as the main
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component with dihydroxyethyl 5-sodiumsulfoisophthalate are used alone or in a combination of two or more.
In the polyester-based fiber for artificial hair, the intrinsic viscosity of the polyester resin, that is, the
intrinsic viscosity of the polyester resin after being processed into fiber is 0.3 to 0.5, preferably 0.35 to 0.5, and
more preferably 0.4 to 0.5. When the polyester resin in the polyester-based fiber for artificial hair has an
intrinsic viscosity of 0.3 or more, the polyester-based fiber for artificial hair has excellent flame retardance and
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does not drip during a combustion test. In addition, the polyester-based fiber for artificial hair also has
excellent heat resistance and is not softened during setting with a hair iron at a high temperature. When the
polyester resin in the polyester-based fiber for artificial hair has an intrinsic viscosity of 0.5 or less, the
polyester-based fiber for artificial hair has excellent heat resistance and is not easily caused to shrink by heat.
Thus, the fiber is not likely to be crimped during setting with a hair iron at a high temperature.
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In the present invention, the intrinsic viscosity of the polyester resin that is used as the raw material
(before being processed into fiber) may be selected as appropriate so that the polyester resin in the fiber (after
being processed into fiber) has an intrinsic viscosity of 0.3 to 0.5, and is not particularly limited. As will be
described later, in the case where a viscosity-reducing agent is used to reduce the intrinsic viscosity of the
polyester resin, the intrinsic viscosity of the polyester resin before being processed into fiber is preferably 0.4 or
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more, more preferably 0.5 or more, and even more preferably 0.6 or more.
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Although there is no particular limitation to the brominated epoxy flame retardant, for example, it is
possible to use as a raw material a brominated epoxy flame retardant having an epoxy group, tribromophenol,
tetrabromobisphenol A, or the like at the end of the molecule.
Specifically, the brominated epoxy flame retardant may be a compound induding a structural formula
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represented by general formula (1) below in the molecule.
Chemical Formula 1
-
(1)
OCH 2CHCF1 2
01-1
rr
In general formula (1) above, m is 1 to 1000.
The brominated epoxy flame retardant preferably has a number-average molecular weight of 1000
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to 20000, more preferably 2000 to 15000, and even more preferably 2000 to 10000. When the brominated
epoxy flame retardant has a number-average molecular weight within the above-described range, the
brominated epoxy flame retardant is easily dispersed in the polyester resin, resulting in favorable color
development and also excellent spinning stability.
From the standpoint of preventing fiber fusion, it is preferable that the brominated epoxy flame
15 retardant has tribromophenol and/or tetrabromobisphenol A, more preferably tetrabromobisphenol A, at the
end of the molecule. When a brominated epoxy flame retardant having a low number-average molecular
weight has an epoxy group at the end of the molecule, the reactivity with the polyester resin is excessively high.
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Thus, a gel is generated during melt kneading and/or melt spinning, and there is a risk that fiber fusion may
occur. In contrast, when a brominated epoxy flame retardant having a low number-average molecular weight
has tribromophenol and/or tetrabromobisphenol A at the end of the molecule, the reactivity with the polyester
resin is not high. Thus, generation of the gel during melt kneading and/or melt spinning is suppressed, and
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fiber fusion is unlikely to occur.
In the present invention, a brominated epoxy flame retardant having the above-described structure at
the end of the molecule is used as the raw material. However, there is no particular limitation to the structure
of the brominated epoxy flame retardant after melt kneading and/or melt spinning. For example, the end of
the molecule of the brominated epoxy flame retardant may be replaced by an epoxy group, a hydroxyl group,
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a phosphoric acid group, or a phosphonic acid group. Alternatively, the end of the molecule of the bronninated
epoxy flame retardant may be bound to the polyester resin through an ester group.
The brominated epoxy flame retardants may be used alone or in a combination of two or more.
Preferably, the polyester-based fiber for artificial hair indudes 5 to 40 parts by weight of the
brominated epoxy flame retardant with respect to 100 parts by weight of the polyester resin. More preferably,
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the polyester-based fiber for artificial hair indudes 5 to 30 parts by weight and even more preferably 6 to 25
parts by weight of the brominated epoxy flame retardant with respect to 100 parts by weight of the polyester
resin. When the content of the brominated epoxy flame retardant is within the above-described range, the
polyester-based fiber for artificial hair has excellent flame retardance, color development, and spinning
properties.
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Preferably, the polyester-based fiber for artificial hair indudes 0.1 parts by weight or more and less
than 5 parts by weight of a viscosity-reducing agent with respect to 100 parts by weight of the polyester resin.
More preferably, the polyester-based fiber for artificial hair includes 0.2 to 4 parts by weight, even more
preferably 0.4 to 3 parts by weight, and particularly preferably 0.8 to 3 parts by weight of the viscosity-reducing
agent with respect to 100 parts by weight of the polyester resin.
The viscosity-reducing agent is a sugar alcohol and/or a bisphenol-based compound containing two
or more hydroxyl groups in the molecule and having a melting point of 80°C or more and a boiling point of
260°C or more. In the present invention, the sugar alcohol and/or the bisphenol-based compound containing
two or more hydroxyl groups in the molecule and having a melting point of 80°C or more and a boiling point of
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260°C or more has an effect of reducing the intrinsic viscosity of the polyester resin, and improves the heat
resistance and color development of the polyester-based fiber for artificial hair by reducing the intrinsic viscosity
of the polyester resin. When two or more hydroxyl groups are present in the molecule, the sugar alcohol
and/or the bisphenol-based compound has good reactivity with the polyester resin and easily reduces the
intrinsic viscosity of the polyester resin. Moreover, when the melting point is 80°C or more, the sugar alcohol
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and/or the bisphenol-based compound does not decompose during steps such as melt kneading or melt
spinning of the polyester resin composition, and can exert the function of a viscosity-reducing agent.
Furthermore, when the boiling point is 260°C or more, the sugar alcohol and/or the bisphenol-based
compound does not function as a plasticizer and functions as a viscosity-reducing agent, and thus the heat
resistance of the polyester-based fiber for artificial hair is not reduced.
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The sugar alcohol that is used as the viscosity-reducing agent may be any sugar alcohol containing
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two or more hydroxyl groups in the molecule and having a melting point of 80°C or more and a boiling point of
260°C or more, and is not particularly limited. Examples thereof include erythritol, pentaerythritol, and sorbitol.
More preferably, the sugar alcohol that is used as the viscosity-reducing agent has a melting point of 120°C or
more. Also, it is more preferable that the sugar alcohol that is used as the viscosity-reducing agent has a
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boiling point of 270°C or more.
The bisphenol-based compound that is used as the viscosity-reducing agent may be any
bisphenol-based compound containing two or more hydroxyl groups in the molecule and having a melting
point of 80°C or more and a boiling point of 260°C or more, and is not particularly limited. Examples thereof
include tetrabromobisphenol A and tetrabromobisphenol S. More preferably, the bisphenol-based compound
10 that is used as the viscosity-reducing agent has a melting point of 120°C or more. Also, it is more preferable
that the bisphenol-based compound that is used as the viscosity-reducing agent has a boiling point of 270°C or
more.
With regard to the viscosity-reducing agent, a single compound may be used alone, or two or more
compounds may be used in combination.
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The sugar alcohols and the bisphenol-based compounds that are used as the viscosity-reducing
agent may be present in a state in which they are bound to the polyester resin through an ester bond in the
polyester-based fiber for artificial hair.
The polyester-based fiber for artificial hair may contain various kinds of additives such as a flame
retardant other than the brominated epoxy flame retardant, a flame retardant auxiliary, a stabilizer, a fluorescent
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agent, an antioxidant, and an antistatic agent as needed without impeding the effects of the present invention.
The polyester-based fiber for artificial hair of the present invention can be obtained by, for example,
melt spinning a polyester resin composition containing a polyester resin and a brominated epoxy flame
retardant by an ordinary melt spinning method. The polyester resin composition can be obtained by dry
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blending each of the above-described components such as the polyester resin, the brominated epoxy flame
retardant, and the viscosity-reducing agent, and melt kneading the mixture using various general kneading
machines. Examples of the kneading machines include a single-screw extruder, a twin-screw extruder, a roll,
a Banbury mixer, and a kneader. In particular, the twin-screw extruder is preferred in terms of the adjustment
of the degree of kneading and the ease of operation. Melt kneading is preferably performed at a temperature
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of not lower than the melting point of the polyester resin, for example, at a temperature of 250 to 280°C,
although there is no limitation thereto.
Preferably, the polyester resin composition includes 5 to 40 parts by weight of the brominated epoxy
flame retardant with respect to 100 parts by weight of the polyester resin. More preferably, the polyester resin
composition includes 5 to 30 parts by weight and even more preferably 6 to 25 parts by weight of the
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brominated epoxy flame retardant with respect to 100 parts by weight of the polyester resin.
In addition, the
polyester resin composition preferably includes 0.1 parts by weight or more and less than 5 parts by weight,
more preferably 0.2 to 4 parts by weight, even more preferably 0.4 to 3 parts by weight, and particularly
preferably 0.8 to 3 parts by weight of the viscosity-reducing agent with respect to 100 parts by weight of the
polyester resin.
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The polyester-based fiber for artificial hair is preferably produced by melt kneading the polyester resin
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composition including the polyester resin, the brominated epoxy flame retardant, and the viscosity-reducing
agent and melt spinning the melt-kneaded polyester resin composition. When a polyester resin having an
intrinsic viscosity of more than 0.5 is used as a raw material polyester resin, and an adjustment is made by
reducing this intrinsic viscosity using a sugar alcohol and/or a bisphenol-based compound containing two or
0
more hydroxyl groups in the molecule and having a melting point of 80°C or more and a boiling point of 260°C
or more so that the polyester resin after being processed into fiber has an intrinsic viscosity within a range of
0.3 to 0.5, a polyester-based fiber for artificial hair having good spinning properties and exhibiting excellent
flame retardance, heat resistance, and color development can be produced. When the polyester resin
composition indudes the sugar alcohol and/or the bisphenol-based compound containing two or more
10 hydroxyl groups in the molecule and having a melting point of 80°C or more and a boiling point of 260°C or
more (viscosity-reducing agent), the viscosity-reducing agent reduces the intrinsic viscosity of the polyester
resin during melt kneading and/or melt spinning.
In the case where the polyester-based fiber for artificial hair of the present invention is produced by
melt spinning by performing an ordinary melt spinning method, for example, the polyester resin composition is
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melt spun into yams while the temperatures of an extruder, a gear pump, a spinneret, and the like are set to
250 to 310°C. Then, the obtained yams are cooled to a temperature of not more than the glass transition
point of the polyester resin, and wound up at a speed of 50 to 5000 m/min, and thus spun yams (undrawn
yams) are obtained. Moreover, the spun yams may also be cooled in a water bath containing cooling water
so as to control the fineness. The temperature and amount of the cooling air applied, the temperature of the
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cooling water bath, the cooling time, and the winding speed can be adjusted appropriately in accordance with
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the extrusion rate of the polymer and the number of holes of the spinneret.
In the present invention, it is preferable that the obtained spun yams (undrawn yams) are hot drawn.
The drawing may be performed by either a two-step method or a direct drawing method. In the two-step
method, the spun yams are once wound, and then drawn. In the direct drawing method, the spun yams are
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drawn continuously without winding. The hot drawing may be performed by a single-stage drawing method
or a multi-stage drawing method that includes two or more stages. The heating means for the hot drawing
may be a heating roller, a heat plate, a steam jet apparatus, or a hot water bath, and they can be used in
combination as desired.
It is preferable that the polyester-based fiber for artificial hair of the present invention is a fiber like
10 non-crimped raw silk. In addition, the polyester-based fiber for artificial hair preferably has a fineness of 10 to
100 dtex, more preferably 20 to 90 dtex, and even more preferably 35 to 80 dtex because the fineness within
the above-describe range is suitable for artificial hair.
The polyester-based fiber for artificial hair of the present invention has favorable flame retardance
and heat resistance.
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The flame retardance of the polyester-based fiber for artificial hair can be determined based on the
LOI value and whether or not dripping occurs during a combustion test. Measurement of the LOI value and
the combustion test can be performed in the manners that will be described later. In light of the excellent
flame retardance of the polyester-based fiber for artificial hair, it is preferable that the LOI value is 23 or more
and no dripping occurs in the combustion test, and it is more preferable that the LOI value is 25 or more and no
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dripping occurs in the combustion test.
The heat resistance of the polyester-based fiber for artificial hair can be determined based on the
heat shrinkage percentage at 220°C that is measured with a TMA (thermal strain and stress measuring
apparatus) and whether or not the fiber is softened and/or crimped by application of heat with a hair iron at
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220°C. Measurement of the heat shrinkage percentage at 220°C with a TMA and application of heat with a
hair iron at 220°C can be conducted in the manners that will be described later. It is preferable that the heat
shrinkage percentage at 220°C of the polyester-based fiber for artificial hair that is measured with a TMA is less
than 5% in light of excellent heat resistance. Moreover, it is preferable that the fiber is not crimped, more
preferably the fiber is not softened, by application of heat with a hair iron at 220°C. It is particularly preferable
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that the heat shrinkage percentage at 220°C that is measured with a TMA is less than 5%, and application of
heat with a hair iron at 220°C does not cause any change in the external appearance and texture of the fiber.
The excellent heat resistance enables curl setting and the like to be preferably performed wfth a heat
instrument for beauty treatment, such as a hair iron, at 180 to 240°C.
The polyester-based fiber for artificial hair (multifilament) has little fiber fusion. For example, in the
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case where fiber fusion is evaluated in the manner that will be described later, the number of fused fibers is
preferably less than 50 and more preferably less than 10.
In the case where the polyester-based fiber for artificial hair of the present invention is spun-dyed, the
fiber can be used as it is. However, in the case where the fiber is not spun-dyed, the fiber can be dyed under
the same condition as that of ordinary polyester-based fibers. As a pigment, a dye, an auxiliary, and the like
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to be used for dyeing, those having weather resistance and flame retardance are preferable.
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The polyester-based fiber for artificial hair of the present invention can be directly used alone as
artificial hair. Alternatively, the polyester-based fiber for artificial hair of the present invention can be used as a
fiber bundle for hair by mixing the polyester-based fiber for artificial hair with at least one fiber selected from the
group consisting of human hair, animal hair, polyvinyl chloride-based fibers, modacrylic fibers,
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polyamide-based fibers, polyolefin-based fibers, regenerated protein fibers, and other polyester-based fibers.
The above-described fibers can be mixed as long as the fiber bundle for hair can retain excellent flame
retardance and heat resistance.
A hair ornament product that is formed using the polyester-based fiber for artificial hair of the present
invention has excellent flame retardance and heat resistance. Examples of the hair ornament product include,
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but not limited to, hair wigs, hairpieces, weavings, hair extensions, braided hair, hair accessories, and doll hair.
The hair ornament product may be formed only of the polyester-based fiber for artificial hair of the
present invention. The hair ornament product may also be formed by combining the polyester-based fiber for
artificial hair with at least one fiber selected from the group consisting of human hair, animal hair, polyvinyl
chloride-based fibers, modacrylic fibers, polyamide-based fibers, polyolefin-based fibers, regenerated protein
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fibers, and other polyester-based fibers.
Examples
Hereinafter, the present invention will be described in more detail based on examples. However,
the present invention is not limited to the examples.
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The following compounds were used in the examples and comparative examples.
Polyethylene terephthalate 1 (hereinafter also referred to as "PET1"): product name "RT523"
manufactured by Nippon Unipet Co., Ltd., IV = 0.70
Polyethylene terephthalate 2 (hereinafter also referred to as "PET2"): product name "regenerated
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PET' manufactured by Nihon MTC Co., Ltd., IV = 0.47
Brominated epoxy flame retardant 1 (hereinafter also referred to as "flame retardant 1"): product
name "SRT-20000" manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., number-average molecular weight:
40000, an epoxy-terminated brominated epoxy flame retardant
Brominated epoxy flame retardant 2 (hereinafter also referred to as "flame retardant 2"): product
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name "SRT-2000" manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., number-average molecular weight:
4000, an epoxy-terminated brominated epoxy flame retardant
Brominated epoxy flame retardant 3 (hereinafter also referred to as "flame retardant 3"): product
name "SRI-1540" manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., number-average molecular weight:
3000, a tribromophenol end-capped brominated epoxy flame retardant
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Viscosity-reducing agent 1: pentaerythritol (manufactured by Wako Pure Chemical Industries, Ltd.,
number of hydroxyl groups: 4, melting point: 261°C, boiling point: 276°C)
Viscosity-reducing agent 2: tetrabromobisphenol S (product name "S-400" manufactured by Manac
Incorporated., number of hydroxyl groups: 2, melting point: 300°C, boiling point: 320°C)
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(Examples 1 to 6 and Comparative Examples 1 to 3)
The above described PET1 or PET2 was dried to a moisture content of 100 ppm or less, and then
was dry blended with the above described other compounds in blending ratios shown in Table 1 below. Each
5
of the obtained polyester resin compositions was supplied to a twin-screw extruder, melt kneaded at 280°C,
and pelletized. The pellets were dried to a moisture content of 100 ppm or less. Next, the dried pellets were
supplied to a melt spinning machine, and a molten polymer was extruded at 280°C through a spinneret with
nozzle holes having a nozzle diameter of 0.5 mm and a circular cross-section. The extruded polyrner was
cooled to a temperature of not more than the glass transition temperature of the polyester resin, and wound up
10
at a speed of 60 to 150 m/min to obtain spun yams. The obtained spun yams were drawn to 3 times the
original length at 80°C and heat-treated using a heat roller heated to 200°C. Thus, a polyester-based fiber
(multifilament) having a single fiber fineness of about 60 dtex was obtained. It should be noted that in
Examples 1 to 4, the intrinsic viscosity of the polyester resin was reduced by the viscosity-reducing agent
(sugar alcohol or tetrabromobisphenol S) during melt kneading and/or melt spinning of the polyester resin
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composition.
The intrinsic viscosity of the polyester resins (IV of the polyester resins after being processed into
fiber) of the polyester-based fibers obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was
measured in the following manner. The results are shown in Table 1 below. Also, the heat resistance, flame
retardance, color development, and fiber fusion of the polyester-based fibers obtained in Examples 1 to 6 and
90
Comparative Examples 1 to 3 were measured and evaluated in the following manners. The results are
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shown in Table 1.
(IV of Polyester Resin after Being Processed into Fiber)
A polyester-based fiber was dissolved in a mixed solvent of phenolitetrachloroethane with a weight
5
ratio of 1/1 so that the concentration was 0.25 g/dL, and the IV of the polyester resin in the fiber was measured
at 25°C.
(Heat Resistance)
Heat resistance was determined by the following four criteria based on the shrinkage percentages at
10 220°C of the fiber that was measured with a TMA and the texture and external appearance after an end
(length: 3 cm) of filaments (total fineness: 150000 dtex, length: 50 cm) was heated for 3 seconds with a hair
iron at 220°C.
A: The shrinkage percentage of the fiber is less than 5%, and both the external appearance and the
texture of the fiber remain unchanged after heating with the hair iron when compared with those before
15
heating.
B:The shrinkage percentage of the fiber is less than 5%, but the fiber is softened, and the texture is
slightly hard.
C: The shrinkage percentage of the fiber is 5% or more, a small amount of crimp is observed in the
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fiber, and the texture tends to be rough.
D: The shrinkage percentage of the fiber is 5% or more, distinct crimps are observed in the fiber, and
the texture is significantly rough.
5 <Measurement of Fiber Shrinkage Percentage at 220°C with TMA>
Filaments (length: 2 cm, ten single yams) were used. The shrinkage percentages at 220°C of the
fibers were measured with a TMA (thermal stress and strain measuring apparatus, trade name
'TMA/SS150C" manufactured by Seiko Instruments Inc., working gas: nitrogen, gas flow rate: 30 Um in, rate of
temperature increase: 20°C/min, load: 18 mN). The fiber shrinkage percentage is given by an equation
10 below
fiber shrinkage percentage (%) = 100-[(100xY)/X]
where X is an initial sample length, and Y is a sample length at 220°C.
(Flame Retardance)
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Flame retardance was determined by the following four criteria based on the LOI value and whether
or not dripping occurred in a combustion test.
A: Dripping does not occur, and the LOI value is 25 or more.
B: Dripping does not occur, and the LOI value is 23 or more and less than 25.
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C: Dripping occurs, and the LOI value is 23 or more.
D: Regardless of whether or not dripping occurs, the LOI value is less than 23.
<Measurement of LOI Value>
5
The LOI value was measured conforming to a method specified in JIS L 1091 E (oxygen index test).
Specifically, filaments (length: 16 cm, weight: 0.25 g) were lightly tied together at both ends with a double-sided
adhesive tape, inserted in a twisting device, and twisted. After the filaments were sufficiently twisted, the
filaments were folded in half at the middle and twisted together. The resultant filaments were fastened at both
ends with a Cellophane (registered trademark) tape so that the overall length became 7 cm. The thus
10
obtained sample was pre-dried at 105°C for 60 minutes and further dried in a desiccator for at least 30 minutes.
The dried sample was adjusted to a certain oxygen concentration. After 40 seconds, the top of the sample
was ignited by an igniter with the igniter flame restricted to 8 to 12 mm. The igniter was removed after the
sample ignited. The oxygen concentration at which 5 cm or more of the sample burned or the sample
continued burning for at least 3 minutes was obtained. The test was repeated three times under the same
15
conditions. Thus, the limiting oxygen index (L01) was obtained.
<Combustion Test>
First, 0.7 g of filaments that were cut to a length of 150 mm was tied into a bundle. One end of the
bundle was damped and fixed to a stand so that the effective length was 120 mm, and the bundle was
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suspended vertically. Aflame of 20 mm was applied to the fixed filaments bundle for 3 seconds to cause the
filaments bundle to bum, and whether or not dripping occurred was observed.
(Color Development)
A tow filament having a length of 30 cm and a total fineness of 100000 dtex was visually observed in
5
the sunlight, and color development was evaluated by the following four criteria by comparison with the
external appearance of human hair.
A: The hue of the fiber is dear and similar to that of human hair.
B: The fiber is somewhat cloudy, and its color is slightly less dear in comparison with the external
10 appearance of human hair.
C: The fiber is cloudy, and its color is less clear in comparison with the external appearance of human
hair.
D: The fiber is strongly cloudy, and its color is distinctly less dear in comparison with the external
appearance of human hair.
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(Fiber Fusion)
Twenty fiber bundles (length: 50 cm, weight: 136 g) were combed at least 30 times by running a
comb made of a polyacetal resin (trade name "NEW DELRIN COMB No. 826" manufactured by Uehara Cell)
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from a point 3 cm below the top of the fiber bundles down through it at a speed of 0.3 m/s. Fiber fusion was
determined as follows based on the number of fused fibers that were caught in the comb.
A: The number of fused fibers is less than 10.
B:The number of fused fibers is 10 or more and less than 50.
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C: The number of fused fibers is 50 or more and less than 100.
D: The number of fused fibers is 100 or more.
Table 1
Ex. 1
Ex. 2
Ex. 3
Ex. 4
100
100
100
100
Ex. 5
Ex. 6
Corn.
Corn.
Corn.
Ex. 1
Ex. 2
Ex. 3
100
100
100
20
20
PET1
(parts by weight)
PET 2
100
100
(parts by weight)
Flame retardant 1
20
20
(parts by weight)
Flame retardant 2
20
(parts by weight)
Flame retardant 3
20
20
20
(parts by weight)
Viscosity-reducing
agent 1
3
3
5
3
(parts by weight)
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Viscosity-reducing
agent 2
3
(parts by weight)
IV of polyester
0.40
0.45
0.40
0.40
0.38
0.47
0.62
0.28
0.65
2
2
2
2
2
3
9
1
11
Heat resistance
A
A
A
A
A
A
D
B
D
LOI value
26
26
26
26
26
26
27
24
21
Does
Does
Does
Does
Does
Does
Does
not
not
not
not
not
not
not
Occurs
Occurs
occur
occur
occur
OCCUr
OCCUr
OCCUr
OCCUr
Flame retardance
A
A
A
A
A
A
A
C
D
Color development
A
A
A
B
B
C
A
C
A
8
7
31
2
9
3
5
22
0
A
A
B
A
A
A
A
B
A
resin after being
processed into fiber
Fiber shrinkage
percentage (°/0)
Dripping
Number of fused
fibers
Fiber fusion
As can be seen from the results shown in Table 1 above, the polyester-based fibers of Examples 1 to
6, in each of which the polyester resin (after being processed into fiber) had an IV within a range of 0.3 to 0.5,
had favorable flame retardance and heat resistance. As can be seen from comparisons of Examples 1 to 3
5
with Example 4 and a comparison between Examples 5 and 6, in the cases where a brominated epoxy flame
retardant having a number-average molecular weight within a range of 1000 to 20000 was used, the color
development was improved. As can be seen from comparisons of Examples 1 to 3 with Example 5 and a
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comparison between Examples 4 and 6, the polyester-based fibers obtained by reducing the IV of the
polyester resin before being processed into fiber using a sugar alcohol and/or a bisphenol-based compound
containing two or more hydroxyl groups in the molecule and having a melting point of 80°C or more and a
boiling point of 260°C or more as the viscosity-reducing agent to adjust the IV of the polyester resin after being
5
processed into fiber to a range of 0.3 to 0.5 exhibited superior color development. As can be seen from
comparisons of Examples 1 and 2 with Example 3, in the cases where a brominated epoxy flame retardant
having a low number-average molecular weight of 1000 to 20000 was used, fiber fusion in the case where the
brominated epoxy flame retardant had tetrabromobisphenol A at the end of the molecule was less than that in
the case where the brominated epoxy flame retardant had an epoxy group at the end of the molecule.
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On the other hand, the polyester-based fibers of Comparative Examples 1 and 3, in each of which
the polyester resin after being processed into fiber had an IV of more than 0.5, had poor heat resistance.
Moreover, the polyester-based fiber of Comparative Example 3, which did not contain a brominated epoxy
flame retardant, also had poor flame retardance. The polyester-based fiber of Comparative Example 2, in
which the polyester resin after being processed into fiber had an IV of less than 0.3, was inferior to the
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polyester-based fibers of the examples in both the flame retardance and the heat resistance.
The invention may be embodied in other forms without departing from the spirit or essential
characteristics thereof, The embodiments disclosed in this application are to be considered in all respects as
illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the
foregoing description, and all changes which come within the meaning and range of equivalency of the claims
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are intended to be embraced therein.
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WHAT IS CLAIMED IS:
1.
A polyester-based fiber for artificial hair comprising a polyester resin and a brominated epoxy flame
retardant,
wherein the polyester resin is polyalkylene terephthalate and/or a copolymerized polyester containing
5
polyalkylene terephthalate as a main component, and
the polyester resin has an intrinsic viscosity of 0.3 to 0.5.
2.
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The polyester-based fiber for artificial hair according to claim 1, wherein the brominated epoxy flame
retardant has a number-average molecular weight of 1000 to 20000.
3.
The polyester-based fiber for artificial hair according to daim 1 or 2, comprising 0.1 parts by weight or
more and less than 5 parts by weight of a viscosity-reducing agent with respect to 100 parts by weight of the
polyester resin, the viscosity-reducing agent being a sugar alcohol and/or a bisphenol-based compound
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containing two or more hydroxyl groups in a molecule and having a melting point of 80°C or more and a boiling
point of 260°C or more.
A method for producing the polyester-based fiber for artificial hair according to any one of daims 1 to
26
_s7)
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3, the method comprising:
a step of reducing an intrinsic viscosity of a polyester resin using a viscosity-reducing agent, the
viscosity-reducing agent being a sugar alcohol and/or a bisphenol-based compound containing two or more
hydroxyl groups in a molecule and having a melting point of 80°C or more and a boiling point of 260°C or
Ti
more.
5.
A fiber bundle for hair comprising:
the polyester-based fiber for artificial hair according any one of daims 1 to 3, and at least one fiber
selected from the group consisting of human hair, animal hair, polyvinyl chloride-based fibers, modacrylic fibers,
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polyamide-based fibers, polyolefin-based fibers, regenerated protein fibers, and other polyester-based fibers.
6.
A hair ornament product comprising the polyester-based fiber for artificial hair according to any one of
claims 1 to 3.
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7.
The hair ornament product according to daim 6, further comprising at least one fiber selected from
the group consisting of human hair, animal hair, polyvinyl chloride-based fibers, modacrylic fibers,
polyamide-based fibers, polyolefin-based fibers, regenerated protein fibers, and other polyester-based fibers.
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