U.S. patent application number 15/114139 was filed with the patent office on 2017-01-05 for silicone grease composition.
This patent application is currently assigned to KYODO YUSHI CO., LTD.. The applicant listed for this patent is KYODO YUSHI CO., LTD.. Invention is credited to Iwaki HIROOKA, Terasu YOSHINARI.
Application Number | 20170002285 15/114139 |
Document ID | / |
Family ID | 53878305 |
Filed Date | 2017-01-05 |
United States Patent
Application |
20170002285 |
Kind Code |
A1 |
HIROOKA; Iwaki ; et
al. |
January 5, 2017 |
SILICONE GREASE COMPOSITION
Abstract
The invention provides a silicone grease composition where the
high friction properties are improved, with no decrease of the wear
preventive characteristics. The silicone grease composition
contains a thickener, a base oil containing a silicone oil in an
amount of 50 mass % or more of the total mass of the base oil, and
a metallic oxide with a Mohs hardness of 6 or less as a friction
modifier.
Inventors: |
HIROOKA; Iwaki;
(Fujisawa-shi, Kanagawa, JP) ; YOSHINARI; Terasu;
(Chigasaki-shi, Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KYODO YUSHI CO., LTD. |
Fujisawa-shi, Kanagawa |
|
JP |
|
|
Assignee: |
KYODO YUSHI CO., LTD.
Fujisawa-shi, Kanagawa
JP
|
Family ID: |
53878305 |
Appl. No.: |
15/114139 |
Filed: |
February 18, 2015 |
PCT Filed: |
February 18, 2015 |
PCT NO: |
PCT/JP2015/054383 |
371 Date: |
July 26, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 2201/062 20130101;
C10N 2020/06 20130101; C10M 107/50 20130101; C10M 2201/1006
20130101; C10M 169/06 20130101; C10M 2229/0425 20130101; C10M
2201/061 20130101; C10N 2030/06 20130101; C10M 2215/1026 20130101;
C10N 2050/10 20130101; C10M 115/08 20130101; C10M 2227/045
20130101; C10N 2040/04 20130101; C10M 125/10 20130101; C10M 169/02
20130101; C10M 169/00 20130101; C10M 169/04 20130101; C10M
2229/0415 20130101; C10M 2201/062 20130101; C10N 2010/04 20130101;
C10M 2201/062 20130101; C10N 2010/12 20130101; C10M 2201/062
20130101; C10N 2010/08 20130101; C10M 2201/062 20130101; C10N
2010/08 20130101; C10M 2201/062 20130101; C10N 2010/12 20130101;
C10M 2201/062 20130101; C10N 2010/04 20130101 |
International
Class: |
C10M 107/50 20060101
C10M107/50; C10M 115/08 20060101 C10M115/08; C10M 169/06 20060101
C10M169/06; C10M 169/02 20060101 C10M169/02; C10M 125/10 20060101
C10M125/10; C10M 169/04 20060101 C10M169/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2014 |
JP |
2014-028681 |
Claims
1. A silicone grease composition comprising a thickener; a base oil
comprising a silicone oil in an amount of 50 mass % or more of the
total mass of the base oil; and a friction modifier comprising a
metallic oxide with a Mohs hardness of 6 or less.
2. The silicone grease composition of claim 1, wherein the metallic
oxide has a Mohs hardness of 2 to 6.
3. The silicone grease composition of claim 1, wherein the metallic
oxide is magnesium oxide, zinc oxide or molybdenum oxide.
4. The silicone grease composition of claim 1, wherein the metallic
oxide is contained in an amount of 0.1 to 10 mass % based on the
total mass of the composition.
5. The silicone grease composition of claim 1, wherein the silicone
oil is represented by the following formula (1):
(CH.sub.3).sub.3SiO-[-Si(R1)(R2)-O-]n-Si(CH.sub.3).sub.3 (1)
wherein R1 and R2 are each independently methyl group or phenyl
group, the ratio of group to the whole organic groups being 50 to
100 mol. %.
6. The silicone grease composition of claim 1, wherein the
thickener is a diurea compound represented by the following formula
(2): R3-NHCONH-R4-NHCONH-R5 (2) wherein R3 and R5, which may be the
same or different, each represent a monovalent hydrocarbon group
having 4 to 20 carbon atoms and R4 is a bivalent aromatic
hydrocarbon group having 6 to 15 carbon atoms.
7. The silicone grease composition of claim 1, wherein the
thickener is a mixture of the following three kinds of diurea
compounds represented by formula (2-1), (2-2) and (2-3):
##STR00002## wherein R is octadecyl group.
8. The silicone grease composition of claim 1, wherein the metallic
oxide has an average particle diameter of 2 .mu.m or less.
Description
TECHNICAL FIELD
[0001] The present invention relates to a silicone composition.
More particularly, the invention relates to a silicone grease
composition suitably used for the parts to be lubricated, to be
more specific, the lubrication parts of the clutch, the torque
limiter mechanism and the like where high coefficient of friction
and excellent wear preventive characteristics are needed.
BACKGROUND ART
[0002] In consideration of the global environmental problems,
weight reduction of the automobile has been advancing. In line with
this tendency, a variety of portions tend to use more clutches and
torque limiter mechanisms than ever. Of such a variety of clutches
and torque limiter mechanisms using the grease composition in the
automobile, the engine starter clutch is exposed to the highest
torque and the severest operating conditions.
[0003] The clutch of the engine starter is composed of a clutch
outer, a clutch inner, a roller disposed in a wedge-like space
formed between the clutch outer and the clutch inner to transmit
the rotation of the clutch outer to the clutch inner, and a spring
which works to urge the roller toward the narrower side of the
wedge-like space. When the clutch outer is rotated, the roller
moves toward the narrower side of the wedge-like space and is then
caught between the clutch outer and the clutch inner, thereby
transmitting the rotation to the clutch inner (torque-transmitted
state). Accordingly, the grease composition used for such portions
requires a high coefficient of friction to prevent the slippage of
the clutch outer, the clutch inner and the roller.
[0004] The following silicone grease compositions are
conventionally known: a grease for the overrunning clutch (JP (Hei)
7-35824 B) where a base oil comprising a silicone oil has a
coefficient of friction of 0.18 or more; grease compositions (JP
(Hei) 5-230486 A and JP (Hei) 6-279777 A) comprising as the base
oil organopolysiloxanes having a predetermined ratio of phenyl
group or methyl group; and a traction grease composition (JP
2003-176489 A) comprising finely-divided particles of metallic
oxide, a thickener, and a base oil containing a dimethyl silicone
oil with a predetermined kinematic viscosity in an amount of 1 to
40 mass %. Those grease compositions make use of the advantages of
the silicone oils that the coefficients of friction are high, and
in addition, the surface tensions of the silicone oils range from
20 to 25 dyn/cm2, which are lower than those of other oils, so that
a lubrication film may not readily be formed, thereby easily
attaining to boundary lubrication.
[0005] When the rotational speed of the clutch inner becomes higher
than that of the clutch outer, the roller automatically moves
toward a wider side of the wedge-like space as compressing the
spring, thereby stopping the transmission of the rotation (torque
non-transmitted state). Under such conditions, the clutch outer,
the clutch inner and the roller reach a state of slippage due to
generation of the relative rotation. In light of this, the grease
composition used for such portions is required to have wear
preventive characteristics.
SUMMARY OF INVENTION
[Technical Problem]
[0006] As previously explained, the clutch and the torque limiter
mechanism are required to be smaller in size and lighter in weight
in line with the recent tendency toward weight reduction in the
automobile, and on the other hand, they are exposed to severer
operating conditions. Especially, satisfactory torque transmission
properties are demanded even when the operating conditions become
more and more tough. For that reason, the grease composition is
required to have a higher coefficient of friction. At the same
time, the wear preventive characteristics are also needed when the
grease composition is used for the clutch and the torque limiter
mechanism.
[0007] Accordingly, an object of the invention is to provide a
silicone grease composition having improved frictional
characteristics, without deterioration of the wear preventive
characteristics.
[Solution to Problem]
[0008] To solve the above-mentioned problems, the inventors of the
present invention contrived a grease composition having an
increased coefficient of friction without decrease of the wear
preventive characteristics by adding as the friction modifier a
metallic oxide with a Mohs hardness of 6 or less.
[0009] Namely, the invention provides a grease composition as shown
below
[0010] 1. A silicone grease composition comprising a thickener, a
base oil comprising a silicone oil in an amount of 50 mass % or
more of the total mass of the base oil, and a friction modifier
comprising a metallic oxide with a Mohs hardness of 6 or less.
[0011] 2. The silicone grease composition described in the
above-mentioned item 1, wherein the metallic oxide has a Mohs
hardness of 2 to 6.
[0012] 3. The silicone grease composition described in the
above-mentioned item 1 or 2, wherein the metallic oxide is
magnesium oxide, zinc oxide or molybdenum oxide.
[0013] 4. The silicone grease composition described in any one of
the above-mentioned items 1 to 3, wherein the metallic oxide is
contained in an amount of 0.1 to 10 mass% based on the total mass
of the composition.
EFFECTS OF INVENTION
[0014] According to the invention, a silicone grease composition
where the frictional characteristics are improved without decrease
of the wear preventive characteristics can be provided.
DESCRIPTION OF EMBODIMENTS
<Base Oil>
[0015] A silicone oil is used for the base oil in the grease
composition according to the invention.
[0016] Specific examples of the silicone oil include dimethyl
silicone oil, methylphenyl silicone oil (phenyl-modified silicone
oil), methyl hydrogen silicone oil, polyether-modified silicone
oil, aralkyl-modified silicone oil, fluoroalkyl-modified silicone
oil, alkyl-modified silicone oil, fatty acid ester-modified
silicone oil, and the like. Of the above silicone oils, dimethyl
silicone oil and methylphenyl silicone oil are preferably used. The
silicone oil represented by the following general formula (1) is
particularly preferable:
(CH.sub.3).sub.3SiO-[-Si(R1)(R2)-O-]n Si(CH.sub.3).sub.3 (1)
wherein R1 and R2 are each independently methyl group or phenyl
group, the ratio of methyl group to the whole organic groups being
50 to 100 mol. %.
[0017] The kinematic viscosity of the silicone oil is not
particularly limited, but may preferably be in the range of 20 to
10,000 mm.sup.2/s, more preferably 50 to 2,000 mm.sup.2/s at
25.degree. C. When the kinematic viscosity of the silicone oil is
less than 20 mm.sup.2/s, the base oil may easily separate from the
grease. When the kinematic viscosity exceeds 10,000 mm.sup.2/s, the
torque will increase at low temperatures due to the viscosity
esistance. In any case, the results are practically
undesirable.
[0018] In the above-mentioned formula (1), R1 and R2 are each
independently methyl group or phenyl group, the ratio of the methyl
group to the whole organic groups being 50 to 100 mol. %. When the
molar ratio of the methyl group to the whole organic groups is less
than 50 mol. %, the viscosity greatly varies depending on the
temperature, and the pour point increases and the torque becomes
large at low temperatures. The ratio of the methyl group to the
whole organic groups may preferably be 60 to 100 mol. %, more
preferably 80 to 98 mol. %, and still more preferably 90 to 95 mol.
%.
[0019] The silicone oil may preferably be contained in an amount of
55 to 90 mass %, and more preferably 70 to 90 mass %, with respect
to the total mass of the composition. Such a content of the
silicone oil can favorably lead to high coefficient of
friction.
[0020] The silicone oil may be used in combination with other base
oil components so long as the performance of the silicone oil may
not be impaired. One or more base oil components selected from the
group consisting of mineral oils, poly .alpha.-olefins, polybutene,
alkylbenzene, animal and vegetable oils, organic acid esters,
diesters, polyol esters, polyalkylene glycols, polyvinyl ethers,
polyphenyl ethers, and alkylphenyl ethers can be used. The amount
of other base oil component(s) that can be used in combination with
the silicone oil may preferably be 0 to 50 mass % with respect to
the mass of the silicone oil used for the base oil. In order not to
decrease the high coefficient of friction, the amount of other base
oil component(s) may preferably be 0 to 20 mass %, more preferably
0 to 10 mass %, with respect to the mass of the lubricating base
oil used in the invention. It is most preferable to use no other
base oil component.
<Thickener>
[0021] The thickener used for the grease composition of the
invention is not particularly limited. Specific examples include
soap type thickeners such as lithium soaps and lithium complex
soaps, urea type thickeners such as diurea compounds, inorganic
thickeners such as organoclay and silica, organic thickeners such
as polytetratluoroethylene and melamine cyanurate, and the like. At
least one selected from the above-mentioned group may be used. It
is preferable to select from the group consisting of silica,
lithium soaps, lithium complex soaps and urea compounds. In
particular, the urea compounds are preferable. As the urea type
thickener, diurea compounds are preferable, and in particular the
diurea compounds represented by the following general formula (2)
are preferred:
R3 -NHCONH-R4-NHCONH-R5 (2)
wherein R3 and R5, which may be the same or different from each
other, each represent a residue of monovalent hydrocarbon groups
having 4 to 20 carbon atoms, for example, aliphatic hydrocarbon
groups; alicyclic hydrocarbon groups and aromatic hydrocarbon
groups; and R4 is a bivalent aromatic hydrocarbon group having 6 to
15 carbon atoms.
[0022] The above-mentioned diurea thickener can be obtained by
reacting a predetermined diisocyanate with a predetermined
monoamine in the base oil, for example. Specific examples of the
preferable diisocyanate include diphenylmethane-4,4'-diisocyanate
and tolylene diisocyanate. Examples of the monoamine include
aliphatic amines, aromatic amines and alicyclic amines, or the
mixtures thereof. Specific examples of the aliphatic amines include
octylamine, dodecylamine, hexadecylamine, octadecylamine, and
oleylamine. Specific examples of the aromatic amines include
aniline and p-toluidine. Specific examples of the alicyclic amines
include cyclohexylamine. Of the above-mentioned monoamines,
cyclohexylamine, octylamine, dodecylamine, hexadecylamine,
octadecylamine, or the mixture thereof may preferably be used for
preparation of the diurea thickener. in particular, alicyclic
aliphatic diurea compounds are preferred which can be obtained by
using cyclohexylamine together with octylamine, dodecylamine,
hexadecylamine, octadecylamine or the mixture thereof Further,
alicyclic aliphatic diurea compounds obtained from cyclohexylamine
and octadecylamine, or the mixtures thereof are particularly
preferable. A mixture of the following three kinds of diurea
compounds represented by formula (2-1), (2-2) and (2-3) (where R is
octadecyl group) is most preferable.
##STR00001##
[0023] The content of the thickener, which may appropriately be
adjusted in accordance with the desired consistency is generally 2
to 35 mass %, preferably 5 to 30 mass %, and more preferably 10 to
25 mass %.
[0024] When the content of the thickener is less than 2 mass %, the
resultant product becomes a liquid, which cannot be used as a
grease. When the content of the thickener exceeds 35 mass %, the
resultant grease is not practically desirable because the grease is
so hard that the torque will increase at low temperatures.
<Friction Modifier>
[0025] The grease composition of the invention comprises as the
friction modifier a metallic oxide with a Mohs hardness of 6 or
less.
[0026] The addition of the metallic oxide as the friction modifier
can increase the coefficient of friction because the oil film
becomes easy to break due to the metallic oxide entering into the
surfaces to be lubricated. Even when the lubrication member is made
of steel, use of the metallic oxide with a Mohs hardness of 6 or
less can increase the coefficient of friction, with damage to the
steel being minimized.
[0027] More specifically, magnesium oxide, potassium oxide, calcium
oxide, scandium oxide, titanium oxide, vanadium oxide, chromium
oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide,
copper oxide, zinc oxide, gallium oxide, germanium oxide, strontium
oxide, yttrium oxide, zirconium oxide, niobium oxide, molybdenum
oxide, technetium oxide, nithenium oxide, rhodium oxide, palladium
oxide, silver oxide, indium oxide, tin oxide, antimony oxide,
tellurium oxide, barium oxide, hafnium oxide, tantalum oxide,
tungsten oxide, rhenium oxide, lead oxide, and silicon oxide can be
used. Particularly, magnesium oxide, zinc oxide and molybdenum
oxide are preferable. The Mohs hardness of the metallic oxide is
preferably 6 or less, more preferably 2 to 6, and still more
preferably 4 to 6. The Mohs hardness of more than 6 is not
favorable because the abrasion will become harsh during the idling
operation in the torque non-transmitted state.
[0028] The metallic oxide may preferably have an average particle
diameter of 10 .mu.m or less, more preferably 5 .mu.m or less, and
still more preferably 2 .mu.m or less. When the average particle
diameter exceeds 10 .mu.m, it becomes difficult for the metallic
oxide particles to come between the surfaces to be lubricated, and
therefore a sufficient effect cannot be expected. The BET
conversion method by N.sub.2-adsorption may be used to determine
the average particle diameter herein used.
[0029] The metallic oxide may preferably he contained in an amount
of 0.1 to 10.0 mass %, more preferably 0.3 to 7.0 mass %, still
more preferably 0.5 to 5.0 mass %, and most preferably 1.0 to 3.0
mass %, based on the total mass of the composition. When the
content of the metallic oxide is less than 0.1 mass %, a sufficient
effect cannot be expected. When the content of the metallic oxide
exceeds 10.0 mass %, the cost will be disadvantageous because the
effect is saturated.
<Other Additives>
[0030] Other additives conventionally used for grease, such as an
antioxidant, rust inhibitor, metal deactivator, detergent
dispersant; extreme pressure agent, antifoaming agent, demulsifier,
oilness improver, solid lubricant and the like may be incorporated.
Those auxiliary additives may be used alone or in combination. The
auxiliary additives may be added if necessary, and in this case,
the contents may be 0.01 to 10 mass % generally. However, the
contents of those additives are not particularly limited as far as
the effects of the invention are not degraded.
<Consistency>The grease composition of the invention may
preferably have a worked penetration of 200 to 400, more preferably
230 to 380, and most preferably 250 to 350.
[0031] According to one preferable embodiment of the invention, the
silicone grease composition comprises; a mixture of three kinds of
diurea compounds represented by the above-mentioned formulas (2-1),
(2-2) and (2-3) a thickener, a base oil consisting of the silicone
oil represented by the above-mentioned formula (1), with no other
base oil component being added, and magnesium oxide, zinc oxide or
molybdenum oxide as a friction modifier.
[0032] In the above embodiment, it is more preferable that the
silicone grease composition comprise a mixture of three kinds of
diurea compounds represented by the above-mentioned formulas (2-1),
(2-2) and (2-3) as the thickener; the base oil consisting of the
silicone oil represented by the above-mentioned formula (1) where
R1 and R2 are each independently methyl group or phenyl group, with
the ratio of methyl group to the whole organic groups being 50 to
100 mol. %, with no other base oil component being added; and
magnesium oxide or zinc oxide or molybdenum oxide as the friction
modifier, with the amount of the friction modifier being 0.1 to 10
mass % based on the total mass of the composition.
[0033] In the above embodiment, it is most preferable that the
silicone grease composition comprise a mixture of three kinds of
diurea compounds represented by the above-mentioned formulas (2-1),
(2-2) and (2-3) as the thickener; the base oil consisting of the
silicone oil represented by the above-mentioned formula (1) where
R1 and R2 are each independently methyl group or phenyl group, with
the ratio of methyl group to the whole organic groups being 95 mol.
%, with no other base oil component being added; and magnesium
oxide as the friction modifier, with the amount of the friction
modifier being 1.0 to 3.0 mass % based on the total mass of the
composition.
[0034] The silicone grease composition of the invention can be
suitably used for the portions to be lubricated where a high
coefficient of friction and excellent wear preventive
characteristics are needed, to be more specific, the portions of
clutch and torque limiter mechanism. More specifically, the
silicone grease composition of the invention is usable for the
overrunning clutch of automobile starters, the one way clutch of
office equipment, a variety of traction driving mechanisms, and the
like. Desirably, the surface of the portions to be lubricated may
be a member made of steel.
EXAMPLES
<Preparation of Silicon Grease Compositions>
Base Oil
[0035] A silicone oil of formula (1) where R1 and R2 are each
independently methyl group or phenyl group, with the ratio of
methyl group to the whole organic groups being 95 mol. % was
used.
Thickener
[0036] An alicyclic aliphatic diurea prepared from
diphenylmethane-4,4'-diisocyanate, cyclohexylamine and
octadecylamine was used.
Friction Modifiers
[0037] Magnesium oxide (Mohs hardness: 5-6; Average particle
diameter: 0.5 .mu.m) [0038] Zinc oxide (Mohs hardness: 4-5; Average
particle diameter: 0.2 .mu.m) [0039] Molybdenum oxide (Mohs
hardness: 2-3; Average particle diameter: 2.1 .mu.m) [0040]
Titanium oxide (Mohs hardness: 7-8; Average particle diameter: 0.15
.mu.m) [0041] Boron nitride (Mohs hardness: 10; Average particle
diameter: 4 .mu.m)
[0042] Predetermined amounts of amines (i.e., cyclohexylamine and
octadecylamine) were reacted with diphenylmethane diisocyanate in
the base oil to prepare a base grease. By adding the base oil and
other additives to the base grease, the resultant mixture was
subjected to a milling treatment so as to have a worked penetration
of 300 (PS K2220), thereby obtaining a grease composition.
<Test Methods>
Low-Speed and High-Load Friction Test
[0043] In this test, the lubrication conditions of the clutch in
the torque-transmitted state were assumed.
[0044] The test was conducted using a Falex test machine as
prescribed in ASTM D2670.
[0045] A test grease was applied to the journal and the blocks. A
predetermined load was applied to both blocks against the journal
in advance, and the test machine rotated the journal for one
second. The generated frictional force was recorded, and then the
initial coefficient of friction was determined 0.001 sec after
starting. The test pieces and the test conditions are as shown
below. [0046] Journal: outer diameter 1/4n, SAE 3135 Steel, Rh
87-91 [0047] Blocks: AISI 1137 Steel, Rc 20-24 [0048] Contact
pressure: 200 kgf/mm.sup.2 [0049] Circumferential speed: 0.096
m/sec
High-Speed and Low-Load Abrasion Test
[0050] In this test, the lubrication conditions of the clutch in
the torque non-transmitted state were assumed.
[0051] The test was conducted using a LFW#1 test machine as
prescribed in ASTM D2714. A load was applied to a roller against a
ring. The test machine rotated the ring to determine the abrasion
occurring on the roller using a micrometer. The test pieces and the
test conditions are as shown below [0052] Ring: outer diameter 35
mm.times.width 8.7 mm, SAE 4620 Steel, Rc 58-63, RMS 6-12
[0053] Roller: Cylindrical roller for roller bearing, diameter 6
mm.times.6 mm, SUJ-2 [0054] Contact pressure: 10 kgf/mm.sup.2
[0055] Circumferential speed: 12.8 m/sec
<Evaluation Criteria>
Low-Speed and High-Load Friction Test
Coefficient of Friction:
[0055] [0056] oo: 0.030.ltoreq..mu. [0057] o:
0.025.ltoreq..mu.<0.030 [0058] .DELTA.:
0.020.ltoreq..mu..ltoreq.0.025 [0059] x:.mu.<0.020
High-Speed and Low-Load Abrasion Test
Depth of Abrasion
[0059] [0060] o:<6 mm [0061] x:.gtoreq.6 mm
[0062] The results are shown in Tables 1 and 2. In the Tables, the
amounts of the thickeners and the friction modifiers are expressed
by mass %, which is based on the total mass of each grease
composition. The balance is occupied by base oil.
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4
Thickener Alicyclic aliphatic Alicyclic aliphatic Alicyclic
aliphatic Alicyclic aliphatic Type diurea diurea diurea diurea
Ratio 15 mass % 14 mass % 15 mass % 15 mass % Type of base oil
Methylphenyl Methylphenyl Methylphenyl Methylphenyl silicone
silicone silicone silicone Friction Type Magnesium oxide, Magnesium
oxide, Zinc oxide, Molybdenum oxide, modifier 1 mass % 3 mass % 3
mass % 3 mass % Mohs 5-6 5-6 4-5 2-3 hardness Coefficient of 0.031
.smallcircle..smallcircle. 0.032 .smallcircle..smallcircle. 0.028
.smallcircle. 0.022 .DELTA. friction Depth of 4.0 .smallcircle. 4.1
.smallcircle. 5.5 .smallcircle. 3.5 .smallcircle. abrasion (mm)
TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Example
1 Example 2 Example 3 Thickener Alicyclic aliphatic Alicyclic
aliphatic Alicyclic aliphatic Type diurea diurea diurea Ratio 15
mass % 15 mass % 16 mass % Base oil Type Methylphenyl Methylphenyl
Methylphenyl silicone silicone silicone Friction Type Titanium
oxide Boron nitride -- modifier 3 mass % 3 mass % Mohs 7-8 10 --
hardness Coefficient of 0.020 .DELTA. 0.030
.smallcircle..smallcircle. 0.018 x friction Depth of 15.0 x 7.2 x
4.8 .smallcircle. abrasion (mm)
* * * * *