United States Patent 0 "
1
3,314,889
MULTIPURPOSE GREASE COMPOSITION
John B. Christian, Yellow Springs, Ohio, assignor t0 the
United States of America as represented by the Secre
tary of the Air Force
No Drawing. Filed Mar. 27, 1964, Ser. No. 355,511
6 Claims. (Cl. 252-49.6)
3,314,889
Patented Apr. 18, 1967
2
that a grease could not be found which would not pre
maturely become highly fugitive and lost.
By way of speci?c example, while the modi?cation
of various synthetic lubricating ?uids with ?uorine-con
taining compounds has been practiced in the prior art to
achieve high-temperature properties, it has been an un
fortunate related circumstances that the ?uids thus modi
?ed have been subject to a rapid decrease in their vis
The invention described herein may be manufactured
cosity as their temperature is elevated. While the prior
and used by or for the Government of the United States
of America for governmental purposes without the pay 10 art attempts to reverse this tendency, including certain
efforts to modify the base ?uid by the addition of small
ment of any royalties thereon or therefor.
amounts of halogen-containing materials, have met with
This invention relates to a new composition of matter
some degree of success, the direction of the research and
More par
ticularly this invention relates to a multipurpose grease 15 development prior to the teachings of this invention has
been primarily toward the modi?cation of the ?uid itself
which is operational under heavy-load and high-speed
and has not considered utilizing the various halogen
conditions over a broad temperature range.
suitable for use as a multipurpose grease.
Recent advancements in the technology of high-speed
engines such as those used in supersonic aircraft and the
containing organic materials as ?llers or thickencrs to
achieve a grease-like consistency or in quantities which
attendant encounters with high temperatures resulting 20 would render them operable as such. Conceivably, the
art has been led away from the use of organic grease thick
from the higher speeds of operation and the new environ
eners in general ‘and halogen-containing organic materials
ments into which the vehicles are traveling have long
in particular because of the known tendency of such ma~
demonstrated the inadequacies of petroleum-based lubri
terials
to promote a decrease in viscosity as temperature
cating ?uids and greases. As this has come about,
rises.
The art was perhaps further dissuaded from use
various synthetic lubricating compositions have been de 25
of ?uorine~containing or other organic: ?llers in quantities
veloped and utilized to meet speci?c lubricating needs.
sufficient to thicken the mixture for the reason that, as the
Organosilicon or siloxane lubricating ?uids for example
grease was subjected to high-speed operation under load
are well known for their ability to withstand extreme tem
conditions, such ?llers would tend to separate from the
perature conditions. To meet other speci?c demands, the
organosilicon ?uids have been modi?ed by admixtures 30 base ?uid and “ball up" thereupon either being thrown
from the mechanisim to be lubricated or building up to
therewith of such components as halogenated fatty acids,
interfere with the free movement of the parts. In either.
low molecular weight polymers of per?uorochloroole?ns
event, the separation of the ?ller from the ?uid destroyed
and the like. Of late, particular emphasis has been placed
the grease-like consistency, and lubrication was no longer
upon the incorporation with the organosilicon base ?uid
of various halogen-containing compounds to improve 35 available at the points desired.
The de?ciencies of the known greases are particularly
high-temperature properties; but it is noteworthy that the
apparent and limiting when they are used to provide
use of these compounds has been directed solely toward
lubrication for heavily loaded ball bearings operating
the modi?cation of the properties of the ?uid itself, con
at rotational speeds of from 10,000 to 20,000 revolutions
sidered either as an oil or as a ?uid base for a grease.
per minute. While some greases have been developed
The lubricating ?uids thus considered are to be distin
which will preserve their position and dimensional sta
guished from greases which have a shear strength at least
bility at such speeds and under such loadings, they have
greater than that normally ‘associated with liquids and,
unlike even the most viscous ?uids, are capable of
preserving their dimensional and positional stability.
not possessed su?icient temperature range to withstand
the heat generated by the high speeds or the broad tem
perature range encountered in space travel for example.
From a lubrication standpoint, such a material is of 45
Moreover, attempts to modify grease compositions to
course often desirable in that it can provide continuous
meet the necessary speed, temperature and load require
lubrication at a point at which a liquid ?uid could be
neither con?ned nor continuously supplied. To provide
this “grease-like” consistency, the prior art has long
ments have been further complicated by other limiting
requirements such as resistance to degradation upon ex
combined a variety of organic “?llers” or “thickeners” 50 posure to various petroleum-type fuels and to high-oxi
dation potential environments.
It is accordingly an object of this invention to provide
with the various lubricating base ?uids, from the earlier
petroleum-based ?uids on down through the organosilox
anes above-mentioned. It has become increasingly ap
parent, however, that, while rather substantial improve
an improved multipurpose grease composition.
Yet another object of the invention is to provide such
ments in the desired properties of the lubricating ?uids 55 a composition which will be operational over a broad
temperature range and will preserve its stability and
have been achieved, comparable advancements have not
grease-like characteristics even when the lubricated parts
been attained in compositions suitable for use as greases.
are operating at high speeds and under heavy loads.
Indeed, as the art has sought to utilize the improved base
Still another object of the present invention is to pro
?uids in greases for lubricating applications such as in
vide such a grease composition which will exhibit good
high-speed engines of aircraft or space vehicles where 60
resistance to petroleum-based fuels and oils and will resist
inertial and gravitational in?uences require a grease
operational over a broad temperature range under high
load and high—speed conditions, it has been frustrated in
oxidation or explosion in the presence of high-oxidation
environments such as that associated with the presence
of liquid oxygen.
3,814,889
4
and, on the Pope spindle bearing test under ?ve pound
load, the following results were achieved:
A more speci?c object of the present invention is to
rovide a grease composition wherein the thickener there
f will not separate prematurely from the lubricating base
uid.
To achieve these and other objects and advantages
‘hich will be apparent from a reading of the following
isclosure the present invention teaches the combination
f a high-temperature organosilicon lubricating base ?uid
'ith a novel high-temperature polymeric thickener in a
articular range of proportions. The speci?c base ?uid
mployed pursuant to this invention is a ?uorosilicone
Hours
‘10,000 r.p.m. at 450 degrees Fahrenheit _______ __ 1,000
10,000 r.p.m. at 500 degrees Fahrenheit _______ __
221
20,000 r.p.m. at 400 degrees Fahrenheit _______ __ 1,000
EXAMPLE II
20 parts by weight of polytetra?uoroethylene powder
of the 200 mesh screen size and 80 parts by weight of
the Dow Corning FS 1265 ?uid were admixed as above,
and the resulting compound showed an A.S.T.M. penetra
tion of from 350 to 364. On the Pope spindle bearing
test under the same ?ve pounds loading, the following
uid such as that known as Dow Corning FS 1265 manu
actured and distribute-d under that designation by Dow
Iorning Corporation, Midland, Mich. The speci?c ?uo
osilicone ?uid manufactured and sold under the FS 1265
results were achieved:
Hours
esignation is of a viscosity grade of from 250 to 1,000
10,000 r.p.m. at 450 degrees Fahrenheit _______ __ 300
entistokes at the lower limit and up to 10,000 centistokes
10,000 r.p.m. at 500 degrees Fahrenheit _______ __ 120
t the upper limit, a speci?c gravity within the range of
20,000 r.p.m. at 400 degrees Fahrenheit _______ __ 225
rom 1.24 to 1.30, a freezing point of from —60 degrees
fahrenheit to —25 degrees Fahrenheit, a ?ash point of 20
EXAMPLE III
rom 440 degrees Fahrenheit to 530 degrees Fahrenheit,
40 parts by weight of the polytetra?uoroethylene pow
nd a trace of acidity. More speci?cally FS 1265 can be
der of a 200 mesh screen size and 60 parts by weight of
.esignated as a polymeric tri?uoropropylmethylsiloxane
the Dow Corning FS 1265 ?uorosilicone ?uid were ad
f the composition and structure
25 mixed as set forth in Example I. The A.S.T.M. penetra
tion of this composition was 227 to 232 and the Pope
spindle bearing test under ?ve pound loading gave the
following results:
Hours
30 10,000 r.p.m. at 450 degrees Fahrenheit _______ __
10,000 r.p.m. at 500 degrees Fahrenheit _______ __
20,000 r.p.m. at 400 degrees Fahrenheit _______ __
214
100
140
LS listed on page 1 of Preprint No. 63LC-12, “Boundary
As a standard of comparison for the above, one of the
lubricating Properties of Fluoroalkyl Silicones in Bench
.nd Pump Tests” by H. M. Schiefer and J. Van Dyke, 35 more advanced high-temperature greases available today
is that con-forming to the published military speci?cation
iublished by American Society of Lubrication Engineers,
known as MIL-G-27343 which is designated as a “grease,
Ihicago, Illinois, 1963.
ball and roller bearing for temperatures from minus 100
The organic or polymeric thickener to be employed in
degrees
Fahrenheit to plus 400 degrees Fahrenheit.” The
combination with the ?uorosilicone base ?uid according
o the teachings of this invention is a ?uoroethylene poly 40 greases meeting this speci?cation are generally of the
class consisting of arylurea-thickened silicone type ?uids.
ner in the form of a powder, particularly that with a
The requirements of greases according to this speci?ca
)article size such that it will pass through from a 100
tion are that on the Pope spindle test under ?ve pound
o a 200‘ mesh- screen. The ?uoroethylene polymers thus
load, the grease should be operative for 500 hours at 400
nvolved are of the class consisting of tetra?uoroethylene
degrees Fahrenheit at 110,000 r.p.m.
1nd chlorotri?uoroethylene and are of the type often
A comparison of the above will disclose that the ?uo
iesignated by the trademark “Te?on” which is the prop
roethylene powder in the approximate weight ratio of 30
:rty of E. I. du Pont de Nemours & Company of Wil
parts to 70 parts of the base ?uid provides an operational
life considerably greater than that which could be expected
nington, Del. The ?uoroethylene powders of the sizes
.ndicated are admixed with the ?uorosilicone base ?uid by
:onventional mixing devices and techniques in the Weight
~atios of from 30 to 35 parts of the ?uoroethylene powder
from greases containing substantially different proportions
50 of this particular thickener and of course greater than has
been expected from the prior art greases.
While this invention has been described in considerable
detail in connection with certain preferred embodiments
percent ?uoroethylene powder by weight and from 65 to
and speci?c examples thereof, it is to be understood that
70 percent ?uorosilicone base ?uid by weight.
this particularization has been for the purposes of illus
The improvements in a multipurpose grease compound
tration only and does not limit the scope of the invention
according to this invention which render it particularly
as it is de?ned in the subjoined claims.
adaptable for use in a wide variety of applications, par
I claim:
ticularly involving high-speeds, high-temperatures, and
1. A multipurpose high-speed, heavy-load grease com
high-loads such as are encountered in high-speed aircraft, 60
pound operable over a broad temperature range compris
rocket-powered space vehicles and the like, are demon
ing 65 to 70 parts by weight of a ?uorosilicone base
strated by the following speci?c examples and relevant
?uid of the structure
test data. These examples also illustrate the criticality
:0 from 65 to 70 parts of the ?uorosilicone base ?uid, as
1 result of which the total grease will be from 30 to 35
of the preferred ratio of the ?uoroethylene powder to the
silicone base ?uid.
65
EXAMPLE I
30 parts by weight of a polytetra?uoroethylene powder
‘of a size which would pass through a 200 mesh screen
CH2
CFa
were thoroughly admixed with 70 parts by weight of the
above-described Dow Corning FS 1265 ?uorosilicone base 70
and 35 to 30 parts by weight of a powdered ?uoroethyl
?uid by ?rst stirring in a conventional internal mixer and
ene polymer as a ?ller.
then blending ‘by three passes through a 3-roll paint mill
2. The grease compound of claim 1 wherein the base
with the roller opening set at .002 inch, all at room tem
?uid is characterized by a viscosity grade of from 250 to
perature. Penetration of this grease, measured by means
of the standard A.S,T.M. method, was from 293 to 297; 75 1000 centistokes at the lower limit and up to 10,000 cen~
5
3,314,889
tistokes at the upper limit, a speci?c gravity within the
range of from 1.24 to 1.30, a freezing point of from --60
‘degrees Fahrenheit to -25 degrees Fahrenheit, a ?ash
point of from 440 degrees Fahrenheit to 530 degrees
Fahrenheit, and a trace of acidity.
3. The composition of claim 2 in which the ?ller is
powdered polymeric tetra?uoroethylene.
4. The composition of claim 2 in which the ?ller is
powdered polymeric chlorotri?uoroethylene.
5. A grease according to claim 2 wherein said powder
is of a particle size which will pass through from a 100
6
References Cited by the Examiner
UNITED STATES PATENTS
2,716,129
8/1955
Wilcock et al. ._____ 252—49.6 X
OTHER REFERENCES
Advances in Petroleum Chemistry and Re?ning, by
Kobe et al., vol. 9, Interscience Pub, New York, N.Y.,
1964, page 105.
Synthetic Lubricants, by Gunderson et al., Reinhold
ub. Corp., New York, N.Y., 1962, pages 259 and 317.
mesh to a 200 mesh screen.
6. The composition of claim 5 wherein 70 parts by
weight of ?uorosilicone base ?uid and 30 parts by weight
of polytetra?uoroethylene powder are employed.
DANIEL E. WYMAN, Primary Examiner.
I. VAUGHN, Assistant Examiner.