U.S. patent application number 11/630463 was filed with the patent office on 2007-09-13 for lubricating grease composition.
Invention is credited to Tatsuya Hashimoto, Tetsuhiro Kitahara, Akihiko Shimura.
Application Number | 20070213240 11/630463 |
Document ID | / |
Family ID | 43124944 |
Filed Date | 2007-09-13 |
United States Patent
Application |
20070213240 |
Kind Code |
A1 |
Shimura; Akihiko ; et
al. |
September 13, 2007 |
Lubricating Grease Composition
Abstract
A lubricating grease composition, which comprises a base oil
consisting of a mixture of 100 parts by weight of at least one of a
perfluoropolyether oil (A), represented by
RfO[CF(CF.sub.3)CF.sub.2O].sub.p(CF.sub.2CF.sub.2O).sub.qRf (where
Rf is a perfluoroalkyl group having 1-5 carbon atoms, p+q=2-200,
q/p=0-2, and q may be 0), and a perfluoropolyether oil (B),
represented by F(CF.sub.2CF.sub.2CF.sub.2O).sub.sC.sub.2F.sub.5
(where s=2-100), and 0-100 parts by weight of at least one of a
perfluoropolyether oil (C), represented by
RfO(CF.sub.2CF.sub.2O).sub.m(CF.sub.2O).sub.nRf (where m+n=3-200
and m:n=10-90:90-10), and a perfluoropolyether oil (D), represented
by
RfO[CF(CF.sub.3)CF.sub.2O].sub.a(CF.sub.2CF.sub.3O).sub.b(CF.sub.2O).sub.-
cRf (where a+b+c=3-200, b is 0 or an integer of 1 or more, and c is
an integer of 1 or more), preferably further admixed with a
thickening agent, can suppress corrosion of metallic materials by
corrosive gases and also has a good heat resistance.
Inventors: |
Shimura; Akihiko; (Ibaraki,
JP) ; Kitahara; Tetsuhiro; (Ibaraki, JP) ;
Hashimoto; Tatsuya; (Ibaraki, JP) |
Correspondence
Address: |
BUTZEL LONG
350 SOUTH MAIN STREET
SUITE 300
ANN ARBOR
MI
48104
US
|
Family ID: |
43124944 |
Appl. No.: |
11/630463 |
Filed: |
June 20, 2005 |
PCT Filed: |
June 20, 2005 |
PCT NO: |
PCT/JP05/11257 |
371 Date: |
December 21, 2006 |
Current U.S.
Class: |
508/588 |
Current CPC
Class: |
C10M 169/06 20130101;
C10N 2030/12 20130101; C10M 2213/0626 20130101; C10M 2211/042
20130101; C10M 119/22 20130101; C10M 2205/0285 20130101; C10M
107/38 20130101; C10M 2215/1026 20130101; C10M 105/54 20130101;
C10N 2030/10 20130101; C10N 2030/08 20130101; C10M 2213/0606
20130101; C10M 2229/0515 20130101; C10N 2050/10 20130101; C10M
2207/1236 20130101; C10M 2213/043 20130101; C10M 2207/1236
20130101; C10N 2010/02 20130101; C10M 2207/1236 20130101; C10N
2010/02 20130101 |
Class at
Publication: |
508/588 |
International
Class: |
C10M 143/00 20060101
C10M143/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 25, 2004 |
JP |
2004-187354 |
Claims
1: A lubricating grease composition, which comprises a base oil
consisting of a mixture of 100 parts by weight of at least one of a
perfluoropolyether oil (A), represented by the following general
formula: RfO
[CF(CF.sub.3)CF.sub.2O].sub.p(CF.sub.2CF.sub.2O).sub.qRf where Rf
is a perfluoroalkyl group having 1-5 carbon atoms, p+q=2-200,
q/p=0-2, q can be 0, and CF(CF.sub.3)CF.sub.2O group and
CF.sub.2CF.sub.2O group are bonded at random in the main chain and
a perfluoropolyether oil (B), represented by the following general
formula: F(CF.sub.2CF.sub.2CF.sub.2O).sub.sC.sub.2F.sub.5 where
s=2-100, and 0-100 parts by weight of at least one of a
perfluoropolyether oil (C), represented by the following general
formula: RfO(CF.sub.2CF.sub.2O).sub.m(CF.sub.2O).sub.nRf where Rf
has the same meaning as defined above, m+n=3-200, m:n=10-90:90-10,
and CF.sub.2CF.sub.2O group and CF.sub.2O group are bonded at
random in the main chain and a perfluoropolyether oil (D),
represented by the following general formula: RfO
[CF(CF.sub.3)CF.sub.2O].sub.3(CF.sub.2CF.sub.2O).sub.b(CF.sub.2O).sub.cRf
where Rf has the same meaning as defined above, a+b+c=3-200, b is 0
or an integer of 1 or more, c is an integer of 1 or more, and
FC(CF.sub.3)CF.sub.2O group, CF.sub.2CF.sub.2O group, and CF.sub.2O
group are bonded at random in the main chain.
2: A lubricating grease composition according to claim 1, wherein
viscosity of the perfluoropolyether oils (A), (B), (C), and (D) as
the base oil are each 5-2,000 mm.sup.2/sec. in terms of dynamic
viscosity at 40.degree. C.
3: A lubricating grease composition according to claim 1, wherein a
thickening agent is further contained in a proportion of 0.1-50% by
weight on the basis of the total of the composition.
4: A lubricating grease composition according to claim 1, further
comprising at least one of an antioxidant, an antirust agent, a
corrosion inhibitor, an extreme agent, an oiliness agent, and a
solid lubricant.
5: A lubricating grease composition according to claim 3, further
comprising at least one of an antioxidant, an antirust agent, a
corrosion inhibitor, an extreme agent, an oiliness agent, and a
solid lubricant.
6: A metal surface that is protected by the lubricating grease
composition according to claim 1 against corrosive gases.
7: A metal surface that is protected by the lubricating grease
composition according to claim 3 against corrosive gases.
8: A metal surface that is protected by the lubricating grease
composition according to claim 6 against sulfide gases.
9: A metal surface that is protected by the lubricating grease
composition according to claim 7 against sulfide gases.
Description
TECHNICAL FIELD
[0001] The present invention relates to a lubricating grease
composition, and more particularly to a lubricating grease
composition having a metal surface protective action against
corrosive gases such as a sulfide gas, etc.
BACKGROUND ART
[0002] Greases are widely used in various machines and tools such
as automobiles, electric electronic machines and instruments,
construction machinery, industrial machinery, machine tools,
information-systems, and also parts as their structural components.
Recent trend towards making these machines and tools work faster
together with more size reduction, higher performance, and lighter
weight, etc., inevitably makes the temperatures of the peripheral
machines and tools higher and higher. To meet the requirements for
lighter weight, lower cost, tighter sealing, etc., molding products
of resins or rubber have been much more used, and also to meet the
requirement for further quietness improvement, much tighter sealing
is desired.
[0003] The metallic parts are often to be exposed to the atmosphere
of corrosive gases generated from components, etc. contained in
resins or rubber, for example, a sulfide gas, a hydrogen chloride
gas, a sulfer dioxide gas, ammonia, oxygen, etc., due to such use
conditions as higher temperatures and tighter sealing and are also
often to be exposed to such corrosive gases permeated from the
outside due to severe use conditions.
[0004] To solve such problems, it has been proposed to use a grease
comprising a fluorosilicone oil and a fluoro resin to suppress
hydrogen sulfide permeation and prevent corrosion of contact
materials. Besides the fluorosilicone oil, it is said that such
fluorine-containing compounds as fluorocarbon, fluoro ester,
fluorine-modified paraffin oil, fluorine-modified ester oil, etc.
also have the similar effect. However, not all of these
fluorine-containing compounds have the effect on the suppression of
hydrogen sulfide permeation at the same degree. In this connection,
it should be noted that the fluorosilicone oil can suppress the
hydrogen sulfide permeation, but has a poor abrasion resistance,
resulting in abrasion of contact materials. The fluoro ester,
fluorine-modified paraffin oil, and fluorine-modified ester oil
have a poor heat resistance, and thus cannot be used in a higher
temperature atmosphere as a problem.
Patent Literature 1: JP-A-59-189511
[0005] As to the fluorine-based grease, it has been proposed to use
a fluorine-based grease comprising a perfluoropolyether oil having
repeating units, represented by (CF.sub.2CF.sub.2CF.sub.2O).sub.n,
as a base oil to improve the heat resistance and chemical
resistance, where no reference is made to the permeation resistance
to the corrosive gases.
Patent Literature 2: JP-B-2-32314
[0006] Another fluorine-based grease having distinguished
wash-ability, abrasion resistance, leakage resistance, etc. has
been also proposed, where no reference is also made to the
corrosion resistance to corrosive gases, in this case.
Patent Literature 3: JP-A-2001-354986
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0007] An object of the present invention is to provide a
lubricating grease composition capable of suppressing corrosion of
metallic materials, caused by corrosive gases, and also having a
heat resistance.
Means for Solving the Problem
[0008] The object of the present invention can be attained by a
lubricating grease composition, which comprises a base oil
consisting of a mixture of 100 parts by weight of at least one of a
perfluoropolyether oil (A), represented by the following general
formula: RfO
[CF(CF.sub.3)CF.sub.2O].sub.p(CF.sub.2CF.sub.2O).sub.qRf (where Rf
is a perfluoroalkyl group having 1-5 carbon atoms, p+q=2-200,
q/p=0-2, q can be 0, and CF(CF.sub.3)CF.sub.2O group and
CF.sub.2CF.sub.2O group are bonded at random in the main chain),
and a perfluoropolyether oil (B), represented by the following
general formula: F(CF.sub.2CF.sub.2CF.sub.2O).sub.sC.sub.2F.sub.5
(where s=2-100), and 0-100 parts by weight of at least one of a
perfluoropolyether oil (C), represented by the following general
formula: RfO(CF.sub.2CF.sub.2O).sub.m(CF.sub.2O).sub.nRf (where Rf
has the same meaning as defined above, m+n=3-200, m:n=10-90:90-10,
and CF.sub.2CF.sub.2O group and CF.sub.2O group are bonded at
random in the main chain), and a perfluoropolyether oil (D),
represented by the following general formula: RfO
[CF(CF.sub.3)CF.sub.2O].sub.a(CF.sub.2CF.sub.2O).sub.b(CF.sub.2O).sub.cRf
(where Rf has the same meaning as defined above, a+b+c=3-200, b is
0 or an integer of 1 or more, c is an integer of 1 or more, and
CF(CF.sub.3)CF.sub.2O group, CF.sub.2CF.sub.2O group, and CF.sub.2O
group are bonded at random in the main chain). The present
lubricating grease composition can generally further contain a
thickening agent in a proportion of 0.1-50% by weight on the basis
of the total of the composition.
Effect of the Invention
[0009] The present lubricating grease composition can be
effectively used as a metal surface protecting agent for metallic
materials to be exposed to the atmosphere of corrosive gases
including a sulfide gas (sulfur-containing gases such as a hydrogen
sulfide gas, a carbon disulfide gas, etc.), a hydrogen chloride
gas, a sulfur dioxide gas, ammonia, etc., together with a
satisfactory heat resistance, when used in the fields, to which the
perfluoropolyether oil has been so far applied.
[0010] Specifically, the present lubricating grease composition can
be used to lubricate and protect sliding parts and contact parts
between the individual members of ball-and-roller bearings, plain
bearings, sintered bearings, gears, valves, cocks, oil seals,
electric contacts, etc. For example, the present lubricating grease
composition can be used to effectively protect metal surfaces used
in the bearings requiring a heat resistance, a low-temperature
durability, a load resistance, etc. as in automobile hub units,
traction motors, fuel injection units, alternators, etc.; the gears
requiring a high abrasion resistance, low friction characteristics
and a high torque efficiency as in automobile power transmission
units, power window motors, wipers, etc.; the bearings requiring a
low torque and low outgassing properties as in hard discs, flexible
disc memory divices, compact disc drives, optomagnetic disc drives,
etc. in the information systems; sliding parts of bearings or gears
as used in vacuum pumps, resin manufacturing apparatuses,
conveyers, lumber industry machines and tools, chromium coating
apparatuses, etc.; and electric contacts of electric machines and
instruments as used in breakers, relays, switches, etc.
BEST MODES FOR CARRYING OUT THE INVENTION
[0011] Perfluoropolyether oils (A)-(D) cab be obtained in the
following manner, where the perfluoroalkyl group Rf for use herein
generally includes a perfluoromethyl group, a perfluoroethyl group,
a perfluoropropyl group, etc.
[0012] Perfluoropolyether oil (A): obtainable by complete
fluorination of precursor, obtained by photo-oxidation
polymerization of hexafluoropropylene, or both of
hexafluoropropylene and tetrafluoroethylene, or by fluorine gas
treatment of a acid fluoride compound having a terminal
CF(CF.sub.3)COF group resulting from anionic polymerization of
hexafluoropropylene oxide or both of hexafluoropropylene oxide and
tetrafluoroethylene oxide in the presence of a cesium fluoride
catalyst. The resulting products having a dynamic viscosity of
5-2,000 mm.sup.2/sec. at 40.degree. C. are available and can
satisfy the conditions of p+q=2-200 and q/p=0-2:1 in the general
formula for perfluoropolyether oil (A).
[0013] Perfluoropolyether oil (B): obtainable by anionic
polymerization of 2,2,3,3-tetrafluorooxetane in the presence of a
cesium fluoride catalyst, followed by a fluorine gas treatment of
the resulting fluorine-containing polyether
(CH.sub.2CF.sub.2CF.sub.2O).sub.n under ultraviolet irradiation at
160.degree.-300.degree. C. The resulting products having a dynamic
viscosity of 5-2,000-mm.sup.2/sec. at 40.degree. C. are available,
and can satisfy the condition of s=2-100 in the general formula for
perfluoropolyether oil (B).
[0014] Perfluoropolyether oil (C): obtainable by photo-oxidation
polymerization of tetrafluoroethylene. The resulting products
having a dynamic viscosity of 5-2,000 mm.sup.2/sec. at 40.degree.
C. are available and can satisfy the conditions of m+n=3-200 and
m:n=10-90:90-10 in the general formula for perfluoropolyether oil
(C).
[0015] Perfluoropolyether oil (D): obtainable by photo-oxidation of
hexafluoropropene and tetrafluoroethylene. The resulting products
having a dynamic viscosity of 5-2,000 mm.sup.2/sec. at 40.degree.
C. are available, and can satisfy the condition of a+b+c=3-200 in
the general formula for perfluoropolyether oil (D).
[0016] The perfluoropolyether oils (A) and (B) can prevent
permeation of corrosive gases (a sulfide gas, a hydrogen chloride
gas, a sulfur dioxide gas, ammonia, etc.), compared with
perfluoropolyether oils of other structures. The suppression effect
on corrosive gases is due to the C--F bonds in the molecule.
Perfluoropolyether oil (C) of other structure having random bonds
of CF.sub.2O groups has the highest viscosity index, a low
volatility, and a low friction coefficient among the
perfluoropolyether oils, but the presence of CF.sub.2O groups in
the molecule weakens the permeation effect of C--F bonds on
corrosive gases, resulting in corrosion of metallic pieces.
Likewise, perfluoropolyether oil (D) containing CF.sub.2O groups
has a distinguished abrasion resistance, but permits permeation of
corrosive gases, resulting in corrosion of metals.
[0017] At least one of perfluoropolyether oils (A) and (B) is mixed
with perfluoropolyether oils of other structures containing random
bonds CF.sub.2O groups to make a base oil, thereby providing the
base oil with properties having both advantages. For example, a
mixture of 100 parts by weight of at least one of
perfluoropolyether oils (A) and (B) with 0-100 parts by weight,
preferably 2-100 parts by weight, more preferably 5-75 parts by
weight, of at least one of perfluoropolyether oils (C) and (D) of
other structures having a random bond of CF.sub.2O groups can
prevent permeation of corrosive gases and also can show a low
friction property. Particularly, component (C) has such
characteristics as a high viscosity index, a low volatility, a low
friction coefficient, etc., and these advantages can be given to
the lubricating grease composition by using component (C) together
with components (A) and (B). Under more severe conditions, a
proportion of perfluoropolyether oils (C) and (D) of other
structures having a random bond of CF.sub.2O groups can be
reduced.
[0018] On the other hand, fluoro oils having no ether bonds have
poor viscosity index, abrasion resistance and friction resistance,
giving rise to poor conduction due to abrasion of contact
materials, an increase in the friction coefficient at low
temperatures, etc. Thus, perfluoropolyether oils (A) and (B)
property containing ether bonds in the molecule and having a random
bond of CF(CF.sub.3)CF.sub.2O groups and CF.sub.2CF.sub.2O groups
in the main chain can have such characteristics as good viscosity
index, abrasion resistance and friction resistance together, while
maintaining a distinguished suppression effect on the permeation of
corrosive gases, whereby a reduction effect on the corrosion or
abrasion at contact parts can be brought about. These two
perfluoropolyether oils (A) and (B) can be used as a base oil upon
mixing in any desired proportion thereof.
[0019] Base oil consisting of these perfluoropolyether oils (A),
(B), (C), and (D) having a dynamic viscosity of 5-2,000
mm.sup.2/sec., preferably 5-1,500 mm.sup.2/sec. at 40.degree. C.
(as determined according to JIS K2283) can be used. When the
dynamic viscosity is less than 5 mm.sup.2/sec., there are high
risks of increasing the evaporation loss, lowering the oil film
strength, etc. and giving rise to such inconveniences as lowering
of the life, and causing abrasion and seizure. Above 2,000
mm.sup.2/sec., on the other hand, there are high risks of
increasing a viscous drag, etc. and giving rise to such
inconveniences as increased power consumption or torque. A portion
of the perfluoropolyether oils (A) and (B) can be replaced with
poly(.alpha.-olefin) oil, etc. having such a dynamic viscosity as
in the above-mentioned range.
[0020] The base oil can further contain a thickening agent, and the
preferable thickening agent is fluoro resin. The fluoro resin for
use herein includes polytetrafluoroethylene,
tetrafluoroethylene-hexafluropropene copolymer, perfluoroalkylene
resin, etc., which have been so far used as a lubricant.
Polytetrafluoroethylene for use herein is those having a number
average molecular weight Mn of about 1,000 to about 500,000,
prepared by emulsion polymerization, suspension polymerization,
solution polymerization, or the like of tetrafluoroethylene,
thereby forming polytetrafluoroethylene having a number average
molecular weight Mn of about 1,000 to about 1,000,000, followed by
a thermal decomposition treatment, a decomposition treatment by
electron beam irradiation, a physical pulverizing treatment or the
like. Copolymerization reaction of tetrafluoroethylene and
hexafluoropropene, and successive treatment of making the molecular
weight lower can be carried out in the same manner as in the case
of polytetrafluoroethylene, and the copolymers having a number
average molecular weight Mn of about 1,000 to about 600,000 can be
used. Control of the molecular weight can be also made by use of a
chain transfer agent at copolymerization reaction. The resulting
powdery fluoro resin has an average primary particle size of
generally about 500 .mu.m or less, preferably about 0.1-30
.mu.m.
[0021] Other thickening agents for use herein than the fluoro resin
include metal soap such as Li soap, etc., urea resin, minerals such
as bentonite, etc., organic pigments, polyethylene, polypropylene,
polyamide, etc., and it is preferable from the viewpoint of heat
resistance and lubricability to use aliphatic dicarboxylic acid
metal salts, monoamide monocarboxylic acid metal salts, monoester
carboxylic acid metal salts, diurea , triurea, tetraurea, etc.
[0022] These powdery fluoro resin, metal soap, urea, and other
thickening agents can be admixed in a proportion of 0.1-50% by
weight, preferably 10-40% by weight, on the basis of the total of
the composition consisting of the base oil of perfluoropolyether
oils and the thickening agents. Above 50% by weight, the
composition will be too hard, whereas below 0.1% by weight the
thickening effect of the fluoro resin is not brought about,
resulting in deterioration of base oil such as separation of oil,
and any increase in the scattering and leakage prevention is no
more expectable.
[0023] The lubricating grease composition can further contain such
additives so far added to the lubricant as an antioxidant, an
antirust agent, a corrosion inhibitor, an extreme pressure agent,
an oiliness agent, a solid lubricant, etc. The antioxidant
includes, for example, a phenol-based antioxidant such as
2,6-di-t-butyl-4-methylphenol, 4,4'
-methylenebis(2,6-di-t-butylphenol), etc., and an amine-based
antioxidant such as alkyldi-phenylamine, triphenylamine,
phenyl-.alpha.-naphthylamine, phenothiazine,
alkylated-.alpha.-naphthylamine, phenithiazine, alkylated
phenithiazine, etc.
[0024] The antirust agent includes, for example, fatty acid, fatty
acid amine, alkylsulfonic acid metal salts, alkylsulfonic acid
amine salts, oxidized paraffin, polyoxyethylene alkyl ethers, etc.,
and the corrosion inhibitor includes, for example, benzotriazole,
benzimidazole, thiadiazole, etc.
[0025] The extreme pressure agent includes, for example, a
phosphorus-based compound such as phosphoric acid esters,
phosphorous acid esters, phosphoric acid amine salts, etc., a
sulfur-based compound such as sulfides, disulfides, etc.,
dialkyldithiophosphoric acid metal salts, dialkyldithiocarbamic
acid metal salts, etc.
[0026] The oiliness agent includes, for example, fatty acids or
their esters, higher alcohols, polyhydric alcohols or their esters,
aliphatic amines, aliphatic acid monoglycerides, etc.
[0027] The solid lubricant includes, for example, molybdenum
disulfide, graphite, boron nitride, silane nitride, etc.
[0028] The composition can be prepared in the following manner (a)
by admixing a predetermined amount of perfluoropolyether base oil
with a predetermined amount of a thickening agent, followed by
thorough kneading through three rolls or by a high pressure
homogenizer, (b) by adding perfluoropolyether oils and aliphatic
carboxylic acid to a heatable, stirrable reactor vessel, thereby
heating and melting the mixture, and adding a predetermined amount
of a metal hydroxide (and an amide compound or an alcohol compound)
thereto, thereby conducting a metal salt-forming reaction (and
amidation reaction or esterification reaction), followed by cooling
and thorough kneading through three rolls or by a high pressure
homogenizer, or (c) by adding perfluoropolyether oils and an
isocyanate to a heatable, stirrable reactor vessel, heating the
mixture, and adding a predetermined amount of an amine thereto,
thereby conducting reaction, followed by cooling and thorough
kneading through three rolls, or by a high pressure
homogenizer.
EXAMPLES
[0029] The present invention will be described in detail below,
referring to Examples, which are not restrictive of the present
invention. In the following Examples and Comparative Examples,
"parts" and "%" are by weight, unless otherwise specifically
mentioned.
Examples 1 to 10, and Comparative Examples 1 to 4
[0030] [Base Oil] TABLE-US-00001 Dynamic Viscosity (40.degree. C.)
A-1: RfO[CF(CF.sub.3)CF.sub.2O].sub.pRf (component A) 100
mm.sup.2/sec. A-2: RfO[CF(CF.sub.3)CF.sub.2O].sub.pRf (component A)
400 mm.sup.2/sec. A-3:
RfO[CF(CF.sub.3)CF.sub.2O].sub.a(CF.sub.2O).sub.cRf (component D)
400 mm.sup.2/sec. A-4:
RfO(CF.sub.2CF.sub.2O).sub.m(CF.sub.2O).sub.nRf (component C) 85
mm.sup.2/sec. A-5: F(CF.sub.2CF.sub.2CF.sub.2O).sub.sC.sub.2F.sub.5
(component B) 65 mm.sup.2/sec. A-6: poly(.alpha.-olefin) oil 30
mm.sup.2/sec. A-7: fluorosilicone oil 300 mm.sup.2/sec.
[Thickening Agent] [0031] B-1: Emulsion polymerization
polytetrafluoroethylene (Mn: about 100.times.10.sup.3 to about
200.times.10.sup.3; average primary particle size: 0.2 .mu.m)
[0032] B-2: Suspension polymerization polytetrafluoroethylene (Mn:
about 10.times.10.sup.3 to about 100.times.10.sup.3; average
primary particle size: 5 .mu.m) [0033] B-3: Solution polymerization
tetrafluoroethylene-hexafluoropropene copolymer (Mn: about
50.times.10.sup.3 to 150.times.10.sup.3; average primary particle
size: 0.2 .mu.m) [0034] B-4: Lithium azelate [0035] B-5: Reaction
product of hexamethylene diisocyanate and octyl-amine
[0036] Lubricating grease composition were prepared from
combinations of the foregoing base oils and thickening agents, and
subjected to evaluation of properties of the compositions according
to the following test procedures
<Sulfide Gas Test>
[0037] Testing apparatus: constant flow rate flow type, gas
corrosion test apparatus [0038] H.sub.2S concentration: 3% [0039]
Temperature: 40.degree. C. [0040] Humidity: 90% [0041] Time: 96
hours [0042] Test piece : copper plate and silver plate, each 40
mm.times.40 mm.times.5 mm in size [0043] Evaluation method:
silver-plated copper plate surface wiped off the grease after the
test were subjected to EDS (energy dispersion type X-ray
spectrometry) analysis to make evaluation as to whether sulfur was
detected or not on the surfaces <Abrasion Test> [0044] Test
apparatus: Shell four-ball test machine [0045] Test piece: SUJ2
(1/2 inch), grade 20 [0046] Revolution rate : 20 revolutions/sec.
[0047] Load: 392.3N (40 kgf) [0048] Temperature: room temperature
[0049] Time: 60 minutes
[0050] The results are shown in the following Table. TABLE-US-00002
TABLE Abrasion Sulfide gas test test Copper Silver Abrasion Base
oil Thickening agent Plate Plate trace size Ex. 1 (A-1) 70% (B-1)
30% ND ND 1.0 mm Ex. 2 (A-2) 60% (B-2) 40% '' '' 0.9 mm Ex. 3 (A-5)
70% (B-1) 30% '' '' 1.2 mm Ex. 4 (A-1) 42% (A-3) 28% (B-3) 30% ''
'' 1.1 mm Ex. 5 (A-1) 35% (A-4) 35% (B-1) 30% '' '' 0.9 mm Ex. 6
(A-1) 64% (A-6) 18% (B-5) 16% (B-1) 2% '' '' 0.7 mm Ex. 7 (A-1) 64%
(A-6) 18% (B-5) 8% (B-1) 10% '' '' 0.9 mm Ex. 8 (A-2) 42% (A-3) 28%
(B-1) 30% '' '' 0.9 mm Ex. 9 (A-5) 35% (A-3) 35% (B-1) 30% '' ''
1.1 mm Ex. 10 (A-5) 42% (A-4) 28% (B-1) 30% '' '' 1.0 mm Comp.
(A-3) 70% (B-1) 30% D D 1.1 mm Ex. 1 Comp. (A-4) 70% (B-1) 30% ''
'' 1.0 mm Ex. 2 Comp. (A-6) 70% (B-4) 30% '' '' 0.5 mm Ex. 3 Comp.
(A-6) 91% (B-5) 9% '' '' 0.7 mm Ex. 4 Comp. (A-6) 70% (B-1) 30% ND
ND 2.4 mm Ex. 5 Note) ND: no detection of sulfur D detection of
sulfur
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