U.S. patent application number 14/405330 was filed with the patent office on 2015-05-14 for grease composition.
This patent application is currently assigned to JX NIPPON OIL & ENERGY CORPORATION. The applicant listed for this patent is JX NIPPON OIL & ENERGY CORPORATION. Invention is credited to Takashi Arai, Yusuke Ayame, Yuji Shitara.
Application Number | 20150133353 14/405330 |
Document ID | / |
Family ID | 49712065 |
Filed Date | 2015-05-14 |
United States Patent
Application |
20150133353 |
Kind Code |
A1 |
Arai; Takashi ; et
al. |
May 14, 2015 |
GREASE COMPOSITION
Abstract
The grease composition of the present invention comprises at
least one base oil selected from a mineral oil and a synthetic oil,
and based on the total amount of the grease composition, 2 to 35%
by mass of a thickener, 0.05 to 5% by mass of an epoxy compound and
0.1 to 20% by mass of an antiwear additive. The grease of the
present invention is good in stability, lubricity and friction
characteristics and excellent in long-term reliability even under
severe use conditions as compared with conventional grease.
Inventors: |
Arai; Takashi; (Tokyo,
JP) ; Ayame; Yusuke; (Tokyo, JP) ; Shitara;
Yuji; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JX NIPPON OIL & ENERGY CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
JX NIPPON OIL & ENERGY
CORPORATION
Tokyo
JP
|
Family ID: |
49712065 |
Appl. No.: |
14/405330 |
Filed: |
June 5, 2013 |
PCT Filed: |
June 5, 2013 |
PCT NO: |
PCT/JP2013/065600 |
371 Date: |
December 3, 2014 |
Current U.S.
Class: |
508/304 |
Current CPC
Class: |
C10M 2207/289 20130101;
C10N 2020/06 20130101; C10M 2223/045 20130101; C10M 2209/1055
20130101; C10N 2030/52 20200501; C10M 2207/042 20130101; C10M
2219/083 20130101; C10M 2215/1026 20130101; C10M 2223/041 20130101;
C10N 2050/10 20130101; C10N 2020/011 20200501; C10M 2219/046
20130101; C10M 2205/0285 20130101; C10N 2040/02 20130101; C10M
2203/1006 20130101; C10N 2040/04 20130101; C10M 2219/082 20130101;
C10M 169/02 20130101; C10N 2030/10 20130101; C10N 2030/06 20130101;
C10M 2219/068 20130101; C10M 169/06 20130101; C10M 2201/041
20130101; C10M 2207/1285 20130101; C10M 2207/2835 20130101; C10M
2215/04 20130101; C10N 2020/02 20130101; C10M 2209/1055 20130101;
C10M 2209/1085 20130101; C10M 2207/1285 20130101; C10N 2010/02
20130101; C10M 2223/045 20130101; C10N 2010/12 20130101; C10M
2219/046 20130101; C10N 2010/04 20130101; C10M 2223/045 20130101;
C10N 2010/04 20130101; C10M 2219/068 20130101; C10N 2010/12
20130101; C10M 2223/045 20130101; C10N 2010/12 20130101; C10M
2219/068 20130101; C10N 2010/12 20130101; C10M 2207/1285 20130101;
C10N 2010/02 20130101; C10M 2219/046 20130101; C10N 2010/04
20130101; C10M 2223/045 20130101; C10N 2010/04 20130101 |
Class at
Publication: |
508/304 |
International
Class: |
C10M 169/06 20060101
C10M169/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 2012 |
JP |
2012-128206 |
Claims
1. A grease composition comprising: at least one base oil selected
from a mineral oil and a synthetic oil; and based on the total
amount of the grease composition, 2 to 35% by mass of a thickener;
0.05 to 5% by mass of an epoxy compound; and 0.1 to 20% by mass of
an antiwear additive.
2. The grease composition according to claim 1, wherein the epoxy
compound is at least one selected from a phenyl glycidyl ether type
epoxy compound, an alkyl glycidyl ether type epoxy compound, a
glycidyl ester type epoxy compound, an alicyclic epoxy compound, an
epoxidized aliphatic monoester and an epoxidized vegetable oil.
3. The grease composition according to claim 2, wherein the epoxy
compound is an alkyl glycidyl ether represented by the following
formula (1): ##STR00003## wherein R represents a linear or branched
alkyl group having 6 to 20 carbon atoms.
4. The grease composition according to claim 3, wherein the epoxy
compound is at least one selected from octyl glycidyl ether,
2-ethylhexyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl
ether, undecyl glycidyl ether and dodecyl glycidyl ether.
5. The grease composition according to claim 2, wherein the
antiwear additive is at least one selected from an
oxygen-containing compound, a nitrogen-containing compound, an
organophosphorus compound, an organosulfur compound, an
organomolybdenum compound, an alkaline earth metal compound and an
organozinc compound.
6. The grease composition according to claim 5, wherein the
oxygen-containing compound is at least one selected from an ester,
an alcohol, an ether and a carboxylic acid, the nitrogen-containing
compound is at least one selected from an aliphatic amine, an
aliphatic amide and an aliphatic imide, the organophosphorus
compound is at least one selected from a phosphoric acid ester, a
phosphorous acid ester and an acidic phosphoric acid ester amine
salt, the organosulfur compound is at least one selected from a
sulfide compound, and sulfurized fat and oil, the organomolybdenum
compound is at least one selected from molybdenum dithiocarbamate
and molybdenum dithiophosphate, the alkaline earth metal compound
is at least one selected from alkaline earth metal sulfonate salt,
phenate salt and salicylate salt, and the organozinc compound is at
least one selected from a zinc dialkyl, a zinc
dialkyldithiophosphate and a zinc dialkyldithiocarbamate.
7. The grease composition according to claim 2, wherein the
antiwear additive is a solid lubricant.
8. The grease composition according to claim 7, wherein the solid
lubricant is at least one selected from molybdenum disulfide,
graphite, a tetrafluoroethylene resin powder and boron nitride.
9. The grease composition according to claim 2, wherein the
synthetic oil type is at least one selected from a hydrocarbon oil,
a diester, a polyol ester and a polyalkylene glycol compound.
10. The grease composition according to claim 2, wherein the
thickener is at least one selected from lithium soaps, calcium
soaps, aluminum soaps and a urea compound.
11. The grease composition according to claim 5, containing, as the
antiwear additive, an organomolybdenum compound and an organozinc
compound.
12. The grease composition according to claim 5, containing, as the
antiwear additive, an organomolybdenum compound, an organozinc
compound and an organosulfur compound.
13. A grease composition comprising: at least one base oil selected
from a mineral oil and a synthetic oil; and based on the total
amount of the grease composition, 2 to 35% by mass of a thickener;
0.05 to 5% by mass of an epoxy compound; and 0.1 to 20% by mass of
an antiwear additive, wherein the synthetic oil is at least one
selected from a hydrocarbon oil, a diester, a polyol ester and a
polyalkylene glycol compound; the thickener is at least one
selected from lithium soaps, calcium soaps, aluminum soaps and a
urea compound; and the epoxy compound is at least one selected from
an alkyl glycidyl ether type epoxy compound, a glycidyl ester type
epoxy compound and an alicyclic epoxy compound.
14. The grease composition according to claim 13, wherein the
antiwear additive is at least one selected from an
oxygen-containing compound, a nitrogen-containing compound, an
organophosphorus compound, an organosulfur compound, an
organomolybdenum compound, an alkaline earth metal compound and an
organozinc compound.
15. The grease composition according to claim 14, wherein the
oxygen-containing compound is at least one selected from an ester,
an alcohol, an ether and a carboxylic acid, the nitrogen-containing
compound is at least one selected from an aliphatic amine, an
aliphatic amide and an aliphatic imide, the organophosphorus
compound is at least one selected from a phosphoric acid ester, a
phosphorous acid ester and an acidic phosphoric acid ester amine
salt, the organosulfur compound is at least one selected from a
sulfide compound, and sulfurized fat and oil, the organomolybdenum
compound is at least one selected from molybdenum dithiocarbamate
and molybdenum dithiophosphate, the alkaline earth metal compound
is at least one selected from alkaline earth metal sulfonate salt,
phenate salt and salicylate salt, and the organozinc compound is at
least one selected from a zinc dialkyl, a zinc
dialkyldithiophosphate and a zinc dialkyldithiocarbamate.
16. The grease composition according to claim 15, containing, as
the antiwear additive, an organomolybdenum compound and an
organozinc compound.
17. The grease composition according to claim 15, containing, as
the antiwear additive, an organomolybdenum compound, an organozinc
compound and an organosulfur compound.
Description
TECHNICAL FIELD
[0001] The present invention relates to a grease composition.
BACKGROUND ART
[0002] Conventionally, a grease has been used as a lubricant in a
bearing, a constant velocity joint and the like with which an
apparatus such as a driving force transmission mechanism is
provided.
[0003] In recent years, the apparatus such as a driving force
transmission mechanism has tended to be increasingly advanced,
higher in performance, higher in speed, smaller in size and longer
in lifetime, and a bearing, a constant velocity joint and the like
have been used under a high load condition. Therefore, in order to
maintain stable lubrication characteristics for a long period of
time, levels required for characteristics of a grease, in
particular, stability and lubricity as basic performances have been
further higher.
[0004] In addition, in an apparatus with a large number of bearing
systems rotated at a relatively low speed and bearing positions,
the energy saving effect due to a reduction in friction is high.
Then, a measure by a reduction in viscosity of a base oil for use
in a grease is studied. The reduction in viscosity, however,
deteriorates oil film formability in a lubrication part, and thus
has limitations with the occurrence of a lubrication failure in
mind.
[0005] From the above, a grease that is superior in stability and
lubricity and exhibits low friction characteristics is
demanded.
[0006] With respect to the enhancement in stability of a grease,
Patent Literature 1 discloses a grease in which a thickener, (A) a
dialkyldithiocarbamate and (B) an aromatic amine compound are added
to a base oil with a polyol ester and an alkyl phenyl ether mixed,
Patent Literature 2 discloses a grease composition in which a base
oil includes a polyoxyalkylene glycol ether and an additive
includes a quinoline type compound and a benzotriazole type
compound, Patent Literature 3 discloses a grease in which a base
oil is a specific condensed phosphoric acid ester and a specific
thickener such as organic bentonite is blended therewith, Patent
Literature 4 discloses a lubricant containing in a base oil,
fluorinated calcium phosphate also having a thickening effect,
Patent Literature 5 discloses a lubricant composition containing a
thickener and trimagnesium phosphate in a base oil, Patent
Literature 6 discloses a grease containing a thickener and a base
oil including a specific poly-.alpha.-olefin and a specific
ethylene-.alpha.-olefin copolymer, and Patent Literature 7
discloses a grease in which a base oil is a specific
perfluoropolyether, respectively.
[0007] With respect to the enhancement in lubricity of a grease,
Patent Literature 8 discloses a grease containing a powdery
oxymolybdenum dithiocarbamate sulfide composition of a specific
structure, Patent Literature 9 discloses a conductive grease
composition having good lubricity, including an ionic liquid, an
alkaline earth metal salt of a higher fatty acid, and a dispersant,
Patent Literature 10 discloses a grease mixed with a particulate
thickening substance whose rate of increase in viscosity can
satisfy the condition expressed by a specific expression, Patent
Literature 11 discloses a grease containing a thickener, a specific
polytetrafluoroethylene resin powder and a specific zinc
dialkyldithiophosphate in a synthetic base oil, Patent Literature
12 discloses a grease in which a base oil is a perfluoropolyether
and a thickener is a specific fluororesin, and Patent Literature 13
discloses a grease composition containing a silicone oil, a
polyurethane powder and synthetic mica, respectively.
CITATION LIST
Patent Literature
[0008] [Patent Literature 1] Japanese Patent Application Laid-Open
No. 9-3468
[0009] [Patent Literature 2] Japanese Patent Application Laid-Open
No. 2006-249376
[0010] [Patent Literature 3] Japanese Patent Application Laid-Open
No. 2010-174209
[0011] [Patent Literature 4] Japanese Patent Application Laid-Open
No. 2011-21149
[0012] [Patent Literature 5] Japanese Patent Application Laid-Open
No. 2011-57762
[0013] [Patent Literature 6] Japanese Patent Application Laid-Open
No. 2011-148908
[0014] [Patent Literature 7] Japanese Patent Application Laid-Open
No. 2011-256397
[0015] [Patent Literature 8] Japanese Patent Application Laid-Open
No. 2004-2872
[0016] [Patent Literature 9] Japanese Patent Application Laid-Open
No. 2007-99826
[0017] [Patent Literature 10] Japanese Patent Application Laid-Open
No. 2007-231207
[0018] [Patent Literature 11] Japanese Patent Application Laid-Open
No. 2008-101122
[0019] [Patent Literature 12] Japanese Patent Application Laid-Open
No. 2010-65171
[0020] [Patent Literature 13] Japanese Patent Application Laid-Open
No. 2010-138320
SUMMARY OF INVENTION
Technical Problem
[0021] According to studies by the present inventor, however, the
greases described in Patent Literatures 1 to 13 above cannot be
said to be necessarily sufficient in terms of stability and
lubricity under severe use conditions, and have room for
improvement in simultaneously satisfying these characteristics and
friction characteristics.
[0022] The present invention has been made in view of the problems
of the prior art above, and an object thereof is to provide a
grease composition that is good in stability, lubricity and
friction characteristics and excellent in long-term reliability
even under severe use conditions as compared with a conventional
grease.
Solution to Problem
[0023] The present inventors have found that the above problems are
solved by blending a thickener, an epoxy compound and an antiwear
additive with a specific base oil in respective specific
proportions to thereby result in improvements in stability,
lubricity and friction characteristics of a grease, leading to
completion of the present invention.
[0024] That is, the present invention provides grease compositions
according to the following [1] to [10].
[1] A grease composition comprising at least one base oil selected
from a mineral oil and a synthetic oil, and, based on the total
amount of the grease composition, 2 to 35% by mass of a thickener,
0.05 to 5% by mass of an epoxy compound and 0.1 to 20% by mass of
an antiwear additive. [2] The grease composition according to [1],
wherein the epoxy compound is at least one selected from a phenyl
glycidyl ether type epoxy compound, an alkyl glycidyl ether type
epoxy compound, a glycidyl ester type epoxy compound, an alicyclic
epoxy compound, an epoxidized aliphatic monoester and an epoxidized
vegetable oil. [3] The grease composition according to [2], wherein
the epoxy compound is an alkyl glycidyl ether represented by the
following formula (1):
##STR00001##
wherein R represents a linear or branched alkyl group having 6 to
20 carbon atoms. [4] The grease composition according to [3],
wherein the epoxy compound is at least one selected from octyl
glycidyl ether, 2-ethylhexyl glycidyl ether, nonyl glycidyl ether,
decyl glycidyl ether, undecyl glycidyl ether and dodecyl glycidyl
ether. [5] The grease composition according to any one of [1] to
[3], wherein the antiwear additive is at least one selected from an
oxygen-containing compound, a nitrogen-containing compound, an
organophosphorus compound, an organosulfur compound, an
organomolybdenum compound, an alkaline earth metal compound and an
organozinc compound. [6] The grease composition according to [5],
wherein the oxygen-containing compound is at least one selected
from an ester, an alcohol, an ether and a carboxylic acid; the
nitrogen-containing compound is at least one selected from an
aliphatic amine, an aliphatic amide and an aliphatic imide; the
organophosphorus compound is at least one selected from a
phosphoric acid ester, a phosphorous acid ester and an acidic
phosphoric acid ester amine salt; the organosulfur compound is at
least one selected from a sulfide compound, and sulfurized fat and
oil; the organomolybdenum compound is at least one selected from
molybdenum dithiocarbamate and molybdenum dithiophosphate; the
alkaline earth metal compound is at least one selected from
alkaline earth metal sulfonate salt, phenate salt and salicylate
salt; and the organozinc compound is at least one selected from a
zinc dialkyl, a zinc dialkyldithiophosphate and a zinc
dialkyldithiocarbamate. [7] The grease composition according to any
one of [1] to [3], wherein the antiwear additive is a solid
lubricant. [8] The grease composition according to [7], wherein the
solid lubricant is at least one selected from molybdenum disulfide,
graphite, a tetrafluoroethylene resin powder and boron nitride. [9]
The grease composition according to any one of [1] to [8], wherein
the synthetic oil is at least one selected from a hydrocarbon oil,
a diester, a polyol ester and a polyalkylene glycol compound. [10]
The grease composition according to any one of [1] to [8], wherein
the thickener is at least one selected from lithium soaps, calcium
soaps, aluminum soaps and a urea compound. [11] The grease
composition according to [5], containing, as the antiwear additive,
an organomolybdenum compound and an organozinc compound. [12] The
grease composition according to [5], containing, as the antiwear
additive, an organomolybdenum compound, an organozinc compound and
an organosulfur compound.
Advantageous Effects of Invention
[0025] According to the present invention, it is possible to
provide a grease composition that is good in stability, lubricity
and friction characteristics and excellent in long-term reliability
even under severe use conditions as compared with a conventional
grease.
DESCRIPTION OF EMBODIMENTS
[0026] Hereinafter, a preferred embodiment of the present invention
is described in detail.
[0027] A grease composition according to an embodiment of the
present invention comprises at least one base oil selected from a
mineral oil and a synthetic oil, and based on the total amount of
the grease composition, 2 to 35% by mass of a thickener, 0.05 to 5%
by mass of an epoxy compound and 0.1 to 20% by mass of an antiwear
additive.
[0028] [Base Oil]
[0029] As the base oil in the present embodiment, a mineral oil
and/or a synthetic oil for use in a lubricating oil may be
used.
[0030] The mineral oil includes a paraffinic base oil, a naphthenic
base oil and a mixed base oil. These are each a refined lubricating
oil fraction obtained by subjecting a crude oil to distillation at
ordinary pressure and further distillation at reduced pressure and
treating the resulting lubricating oil fraction by an appropriate
combination of lubricating oil-refining procedures such as solvent
deasphalting, solvent extraction, hydrorefining, hydrocracking,
solvent dewaxing, hydrodewaxing and a clay treatment, and may be
suitably used. In particular, a step of controlling the composition
corresponds to solvent extraction, hydrorefining and hydrocracking,
a step of controlling low temperature characteristics such as a
pour point corresponds to solvent dewaxing and hydrodewaxing for
removal of the wax content, and a clay treatment is a step of
removing the nitrogen content mainly to enhance the stability of
the base oil.
[0031] In addition, examples include a lubricating base oil such as
a wax-cracked/isomerized mineral oil obtained by hydrocracking
and/or isomerizing a raw material containing a wax mainly including
n-paraffins, such as a slack wax or GTL WAX (gas to liquid wax)
produced by a Fischer-Tropsch process or the like. A refined
lubricating oil fraction having a different property, obtained from
a combination of various raw materials and various refining
procedures, may be used singly or in combinations of two or more,
and is a suitable base oil.
[0032] In addition, the synthetic oil includes esters such as
monoesters, diesters and polyol esters, ethers such as
polyoxyalkylene glycols, polyvinyl ethers, dialkyl diphenyl ethers
and polyphenylethers, and hydrocarbon oils such as
poly-.alpha.-olefins (PAO), an ethylene-.alpha.-olefin oligomer,
alkylbenzenes and alkylnaphthalenes.
[0033] Esters are compounds having various molecular structures,
and each of them has particular viscosity characteristics and low
temperature characteristics and is a base oil that is characterized
by being high in flash point as compared with a hydrocarbon type
base oil whose viscosity is the same. Esters may be each obtainable
by a dehydration condensation reaction of an alcohol with a
carboxylic acid such as a fatty acid, but, in the present
invention, a suitable base oil component includes diesters of
dibasic acids and monohydric alcohols, polyol esters of polyols (in
particular, neopentyl polyol) and monovalent fatty acids, or
complex esters of polyols, polyvalent basic acids and monohydric
alcohols (or monovalent fatty acids) in terms of chemical
stability.
[0034] Dibasic acids include adipic acid, azelaic acid, sebacic
acid and dodecanedioic acid, and monohydric alcohols include, as
linear monohydric alcohols, butanol, pentanol, hexanol, octanol and
decanol, and, as branched monohydric alcohols, 2-ethylhexanol,
3,5,5-trimethylhexanol and isodecanol.
[0035] Among monovalent fatty acids, specifically, linear fatty
acids include butanoic acid, pentanoic acid, hexanoic acid,
heptanoic acid, octanoic acid, nonanoic acid and oleic acid, and
branched fatty acids include branched butanoic acid, branched
pentanoic acid, branched hexanoic acid, branched heptanoic acid,
branched octanoic acid and branched nonanoic acid. Specifically,
.alpha.- and/or .beta.-branched fatty acids include isobutanoic
acid, 2-methylbutanoic acid, 2-methylpentanoic acid,
2-methylhexanoic acid, 2-ethylpentanoic acid, 2-methylheptanoic
acid, 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid. As
monovalent fatty acids, saturated fatty acids having 4 to 18 carbon
atoms, preferably 6 to 12 carbon atoms, can be used.
[0036] As polyhydric alcohols, polyhydric alcohols having 2 to 6
hydroxyl groups, polyhydric alcohols having 4 to 12 carbon atoms,
are preferably used. Specifically, polyhydric alcohols include
hindered alcohols such as neopentyl glycol, trimethylolethane,
trimethylolpropane, trimethylolbutane, di-(trimethylolpropane),
pentaerythritol and di-(pentaerythritol).
[0037] Ethers include polyalkylene glycols, polyvinyl ethers and
dialkyl diphenyl ethers. Polyalkylene glycols include polypropylene
glycol, polyethylene glycol, and a copolymer of propylene oxide and
ethylene oxide. A compound, in which the hydroxyl group at one end
is etherified and the hydroxyl group at the remaining end remains
as it is, is commonly used, but a compound in which the hydroxyl
groups at both ends are etherified is preferable because of being
low in hygroscopicity, and the backbone thereof is more preferably
an oxypropylene type than an oxyethylene type high in
hygroscopicity. In the present embodiment, a polyalkylene glycol
compound may be suitably used.
[0038] Among hydrocarbon oils, poly-.alpha.-olefins (PAOs) are
widely used, and are polymers of .alpha.-olefins and thus are
characterized by the degree of polymerization. While alkylbenzenes
and alkylnaphthalenes are used in the field of a specific
lubricating oil, they are classified to a linear type and a
branched type depending on the structure of the alkyl group and are
different in terms of characteristics, and thus are used depending
on the purpose.
[0039] Among these base oils, a mineral oil, diesters, polyol
esters, a polyalkylene glycol compound or poly-.alpha.-olefins may
be preferably used.
[0040] In the present embodiment, one of the mineral oil or one of
the synthetic oil may be used singly. In addition, two or more
selected from the group consisting of the mineral oil and the
synthetic oil may be appropriately combined and blended in
appropriate proportions so as to satisfy various performances
required depending on the application. Herein, a plurality of the
mineral oil type base oils and a plurality of the synthetic oil
type base oils may be each used.
[0041] The kinematic viscosity of the base oil at 40.degree. C. is
preferably 3 to 2000 mm.sup.2/s, more preferably 5 to 1000
mm.sup.2/s and further preferably 8 to 500 mm.sup.2/s in order that
the grease composition maintains an appropriate viscous
property.
[0042] The content of the base oil is preferably 60% by mass or
more and more preferably 70% by mass or more based on the total
amount of the grease composition. In addition, the content of the
base oil is preferably 95% by mass or less and more preferably 90%
by mass or less based on the total amount of the composition. If
the content is within this range, lubricity is excellent and it is
possible to stably provide a grease.
[0043] [Thickener]
[0044] The thickener for use in the grease composition according to
the present embodiment is not particularly limited, and all
thickeners usually used for a grease composition may be used.
Examples of the thickener include metal soaps including lithium,
calcium, sodium or aluminum, a urea compound, an imide compound,
Bentone, silica gel, a non-soap thickener such as a fluorinated
thickener typified by polytetrafluoroethylene, and furthermore an
amide compound that is liquid at a temperature equal to or higher
than the melting point of the compound and is a gel-like grease at
room temperature. Among them, metal soaps and a urea compound are
preferable. In addition, among metal soaps, lithium soaps are
particularly preferable.
[0045] Lithium soaps include lithium soaps and lithium complex
soaps. Lithium soaps include lithium metal soaps such as lithium
12-hydroxystearate and lithium stearate, and lithium complex soaps
include lithium soaps with a mixture of a monovalent carboxylic
acid and a polyvalent carboxylic acid (preferably, divalent
carboxylic acid), specifically, a mixture of a reaction product of
12-hydroxystearic acid and lithium hydroxide and a reaction product
of azelaic acid and lithium hydroxide, and the like.
[0046] The urea compound includes a diurea compound, and in
particular, examples of the diurea compound include a diurea
compound obtained by reacting an aromatic amine, an aliphatic
amine, an alicyclic amine or a mixture of two or more of them with
an aromatic diisocyanate. Examples of the aromatic diisocyanate
include tolylene diisocyanate, diphenylmethane diisocyanate and
naphthalene diisocyanate, examples of the aromatic amine include
p-toluidine, aniline and naphthylamine, examples of the aliphatic
amine include octylamine, nonylamine, decylamine, undecylamine,
dodecylamine, tridecylamine and tetradecylamine, and examples of
the alicyclic amine include cyclohexylamine and
methylcyclohexylamine.
[0047] These thickeners are thickeners that are balanced in terms
of characteristics and suitable for practical use in terms of
availability and cost. In the present embodiment, the thickener may
be used singly or in combinations of two or more. The content of
the thickener can be appropriately selected so as to be necessary
for achieving required consistency, but is preferably 2 to 35% by
mass, preferably 5 to 30% by mass and further preferably 5 to 25%
by mass based on the total amount of the grease composition.
[0048] [Epoxy Compound]
[0049] The grease composition according to the present embodiment
comprises an epoxy compound. In the present embodiment, the epoxy
compound and an antiwear additive are used in combination while the
base oil and the thickener are combined, thereby enabling to
enhance stability and wear resistance, and also to simultaneously
satisfy these characteristics and friction characteristics. Herein,
the epoxy compound itself does not usually exhibit the effect of
enhancing wear resistance. In addition, the present inventor has
confirmed that the grease composition according to the present
embodiment is excellent in wear resistance as compared with the
case where no epoxy compound is used and the antiwear additive is
used singly. It is thus found that the above effect by the grease
composition according to the present embodiment is a synergetic
effect by use of the epoxy compound and the antiwear additive in
respective specific contents in combination, and a special effect
that is not exerted by a conventional grease composition.
[0050] The type of the epoxy compound includes an alkyl glycidyl
ether type epoxy compound, a phenyl glycidyl ether type epoxy
compound, a glycidyl ester type epoxy compound, an alicyclic epoxy
compound, an epoxidized fatty acid monoester and an epoxidized
vegetable oil.
[0051] The alkyl glycidyl ether type epoxy compound specifically
includes hexyl glycidyl ether, octyl glycidyl ether, 2-ethylhexyl
glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, undecyl
glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether,
tetradecyl glycidyl ether, oleyl glycidyl ether, neopentyl glycol
diglycidyl ether, trimethylolpropane triglycidyl ether,
pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl
ether, sorbitol polyglycidyl ether, polyalkylene glycol
monoglycidyl ether and polyalkylene glycol diglycidyl ether.
[0052] The phenyl glycidyl ether type epoxy compound includes
phenyl glycidyl ether, methylphenyl glycidyl ether, ethylphenyl
glycidyl ether, propylphenyl glycidyl ether and butylphenyl
glycidyl ether.
[0053] The glycidyl ester type epoxy compound specifically includes
phenyl glycidyl esters, alkyl glycidyl esters and alkenyl glycidyl
esters, and examples include glycidyl-2,2-dimethyl octanoate,
glycidyl benzoate, glycidyl acrylate and glycidyl methacrylate.
Examples include alkyl glycidyl esters in which the number of
carbon atoms in the alkyl group is 4 to 18, in particular, 6 to
12.
[0054] The alicyclic epoxy compound specifically includes
1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3,4-epoxycyclohexyl
methyl-3',4'-epoxycyclohexane carboxylate,
bis(3,4-epoxy-6-methylcyclohexyl methyl)adipate,
2-(7-oxabicyclo[4,1,0]hept-3-yl)-spiro(1,3-dioxane-5,3'-[7]oxabicyclo[4,1-
,0]heptane, 4-(1'-methylepoxyethyl)-1,2-epoxy-2-methylcyclohexane
and 4-epoxyethyl-1,2-epoxycyclohexane. Examples include derivatives
of epoxycycloalkanes having 5 to 7 carbon atoms.
[0055] Epoxidized fatty acid monoesters include esters of
epoxidized fatty acids having 12 to 20 carbon atoms and alcohols
having 1 to 8 carbon atoms, or phenols or alkyl phenols, and
examples include butyl, hexyl, benzyl, cyclohexyl, methoxyethyl,
octyl, phenyl and butyl phenyl esters of epoxy stearic acid.
[0056] The epoxidized vegetable oil includes an epoxy compound of a
vegetable oil such as a soybean oil, a flaxseed oil or a cotton
seed oil.
[0057] In the present embodiment, the epoxy compound incorporates a
carboxylic acid or the like produced along with degradation of the
grease into the molecule to stabilize the carboxylic acid or the
like, and thus suppresses production of a component that causes
corrosion wear and suppresses degradation of the additive to
thereby contribute to an enhancement in lubricity.
[0058] Furthermore, the present inventor has found that alkyl
glycidyl ethers among the epoxy compounds exhibit a different
behavior from other types of epoxy compounds, and result in not
only an enhancement in lubricity by stabilization but also a
significant increase in the effect of the antiwear additive. In
particular, an alkyl glycidyl ether represented by the following
formula (1) is preferable because of resulting in not only an
enhancement in stability but also a large effect of increasing wear
resistance, and furthermore an alkyl glycidyl ether in which R in
the formula (1) represents an alkyl group having 8 to 12 carbon
atoms is more preferable.
##STR00002##
[0059] [wherein R represents a linear or branched alkyl group
having 6 to 20 carbon atoms.]
[0060] Preferred alkyl glycidyl ethers include octyl glycidyl
ether, 2-ethylhexyl glycidyl ether, nonyl glycidyl ether, decyl
glycidyl ether, undecyl glycidyl ether and dodecyl glycidyl
ether.
[0061] In the present embodiment, the epoxy compound may be used
singly or may be used in combinations of two or more.
[0062] The content of the epoxy compound is 0.05 to 5% by mass,
preferably 0.1 to 3% by mass and more preferably 0.1 to 2% by mass
based on the total amount of the grease composition. If the content
is low, no effect of enhancing stability and wear resistance is
exerted, and if the content is too high, characteristics as the
grease are not balanced, for example, an organic material in a
mechanical system is swollen.
[0063] [Antiwear Additive]
[0064] The grease composition according to the present embodiment
comprises an antiwear additive. A preferred antiwear additive
includes an oxygen-containing compound, a nitrogen-containing
compound, an organophosphorus compound, an organosulfur compound,
an organomolybdenum compound, a calcium compound and an organozinc
compound. In addition, a solid lubricant may also be preferably
used. Herein, the antiwear additive may be classified to an
oiliness agent, an antiwear agent and an extreme pressure agent,
but such classification is not necessarily critical. In addition,
one antiwear additive may correspond to two or three of an oiliness
agent, an antiwear agent and an extreme pressure agent. The epoxy
compound for use in the present invention is excluded from the
antiwear additive in the present invention.
[0065] Among the antiwear additives, the oxygen-containing compound
includes higher fatty acids such as oleic acid and stearic acid,
higher alcohols such as oleyl alcohol, esters such as glycerol
monooleate, and ethers such as glycerol monooleyl ether. These
oxygen-containing compounds are typically configured from an
oxygen-containing polar group such as a hydroxyl group, a
carboxylic acid group, an ether group or an ester group and a
saturated or unsaturated hydrocarbon group having 12 to 24 carbon
atoms. It is expected in these oxygen-containing compounds that the
polar group adsorbs to the surface of a metal sliding portion and
the hydrocarbon group forms an oil film to enhance wear resistance.
Examples include partial esters in which a hydroxyl group remains,
in particular, glycerol partial esters with fatty acids having 12
to 24 carbon atoms.
[0066] In addition, the nitrogen-containing compound includes
aliphatic amines such as oleylamine and dodecylamine, aliphatic
amides and aliphatic imides. These nitrogen-containing compounds
are typically configured from a nitrogen-containing polar group
such as an amine group, an amide group or an imide group and a
hydrocarbon group having a saturated or unsaturated bond and having
12 to 24 carbon atoms. It is expected in these nitrogen-containing
compounds that the polar group adsorbs to the surface of a metal
sliding portion and the hydrocarbon group forms an oil film to
enhance wear resistance. In particular, examples include aliphatic
amines having 12 to 24 carbon atoms.
[0067] In addition, the organophosphorus compound includes
phosphoric acid esters, phosphorous acid esters and an acidic
phosphoric acid ester amine salt. In the present invention, it is
to be noted that a compound containing nitrogen or the like, in
addition to phosphorus, as a constituent element, is included in
the organophosphorus compound. The organophosphorus compound is
typically one having one or more hydrocarbon groups having 6 to 24
carbon atoms. Such a hydrocarbon group includes a linear
hydrocarbon group, a branched hydrocarbon group and an aromatic
group. The salt compound in the organophosphorus compound includes
a compound completely neutralized or a compound partially
neutralized. It is expected in such an organophosphorus compound
that a lubricant film of iron phosphate or the like is formed on
the surface of a metal sliding portion to enhance wear resistance.
Examples of phosphoric acid esters include those having an aromatic
group, and typically include triaryl phosphates.
[0068] The organosulfur compound includes a monosulfide compound, a
disulfide compound, a polysulfide compound, sulfurized fat and oil
and sulfurized olefins. It is expected in such an organosulfur
compound that a lubricant film of iron sulfide or the like is
formed on the surface of a metal sliding portion to enhance wear
resistance. Examples include diaryl sulfides, dialkyl sulfides and
dialkenyl sulfides. The sulfur element content in the organosulfur
compound can be, for example, 2 to 70% by mass, in particular, 5 to
60% by mass.
[0069] The organomolybdenum compound includes molybdenum
dithiocarbamate and molybdenum dithiophosphate. In the present
invention, it is to be noted that a compound containing sulfur or
the like, in addition to molybdenum, as a constituent element, is
included in the organomolybdenum compound. It is expected in such
an organomolybdenum compound that a lubricant film made of
molybdenum disulfide is formed on the surface of a metal sliding
portion to enhance wear resistance. Examples include molybdenum
dialkyldithiocarbamates and molybdenum dialkyldithiophosphates in
which the number of carbon atoms in an alkyl group is 4 to 12.
[0070] The alkaline earth metal compound includes alkaline earth
metal sulfonate salt, phenate salt and salicylate salt. The
alkaline earth metal may be selected from calcium, magnesium and
barium. In the present invention, it is to be noted that a compound
containing sulfur or the like, in addition to the alkaline earth
metal, as a constituent element is included in the alkaline earth
metal compound. In addition, the calcium compound may include a
basic component such as calcium carbonate.
[0071] The organozinc compound includes organozinc compounds such
as zinc dialkyls, zinc dialkyldithiophosphates and zinc
dialkyldithiocarbamates. In the present invention, it is to be
noted that a compound containing sulfur, phosphorus or the like, in
addition to zinc, as a constituent element is included in the
organozinc compound. The organozinc compound typically has one or
more linear, branched or aromatic hydrocarbon groups having 6 to 24
carbon atoms. Examples include zinc dialkyldithiophosphates in
which the number of carbon atoms in an alkyl group is 4 to 12.
[0072] In addition, a solid lubricant may also be applied to the
grease being a semi-solid lubricant. The solid lubricant is an
additive that is used in the form of a powder or thin film in order
to prevent the surface of a sliding material from being damaged or
in order to reduce friction/wear, and includes molybdenum
disulfide, tungsten disulfide, graphite, graphite fluoride,
melamine cyanurate, a tetrafluoroethylene (PTFE) resin powder, a
polyimide resin powder, a high-density polyethylene resin powder,
boron nitride, a copper powder, a nickel powder, a tin powder and a
silver powder.
[0073] In particular, molybdenum disulfide, graphite, a
tetrafluoroethylene resin powder and boron nitride may be suitably
used in the present invention.
[0074] In the present embodiment, the antiwear additive may be used
singly or may be used in combinations of two or more. The content
of the antiwear additive is 0.1 to 20% by mass, preferably 0.2 to
20% by mass, more preferably 0.2 to 7% by mass and further
preferably 0.3 to 5% by mass based on the total amount of the
grease composition. If the content is too low, no effect of
wear-resistance is exerted, and if the content is too high, the
stability of the lubricating oil is deteriorated.
[0075] It is preferable to contain the organomolybdenum compound
and the organozinc compound as the antiwear additive. The mass
ratio of the content of the organomolybdenum compound to the
content of the organozinc compound may be, for example, 0.2 to
10:1, in particular, 1 to 5:1. In this case, it is possible to use
a lithium complex soap as the thickener.
[0076] It is preferable to contain the organomolybdenum compound,
the organozinc compound and the organosulfur compound as the
antiwear additive. The mass ratio of the content of the
organomolybdenum compound to the content of the organozinc compound
may be, for example, 1 to 10:1, in particular, 1 to 5:1, and the
mass ratio of the content of the organozinc compound to the content
of the organosulfur compound may be, for example, 0.2 to 2:1, in
particular, 0.5 to 2:1. In this case, it is possible to use a
lithium soap as the thickener. It is possible to use a dialkyl
sulfide having alkyl having 4 to 18, in particular, 6 to 10 carbon
atoms as the organosulfur compound.
[0077] [Other Additives]
[0078] The grease composition according to the present embodiment
may contain, in order to improve its performance, additives such as
an antioxidant, an antirust agent, a metal deactivator, a corrosion
inhibitor, a viscosity index improver, a pour point depressant, a
detergent dispersant, an emulsifier and an antifoamer that have
been conventionally used for a lubricating oil, as long as the
object of the present invention is not impaired.
[0079] The antioxidant includes a phenol type compound like
di-tert-butyl-p-cresol, and an amine type compound like alkyl
diphenyl amines, the antirust agent includes alkenyl succinic acid
esters or partial esters thereof, the metal deactivator includes
benzotriazole and gallic acid esters, the corrosion inhibitor
includes thiadiazole, the viscosity index improver includes
polymethacrylate and polyisobutylene, the pour point depressant
includes polyalkylacrylate and polyalkylstyrene, the detergent
dispersant includes succinic imide and phosphonates, the emulsifier
includes a fatty acid soap and a long-chain alcohol sulfate ester
salt, and the antifoamer includes a silicone compound and a
polyester compound, respectively.
EXAMPLES
[0080] Hereinafter, the present invention is described in more
detail based on Examples and Comparative Examples, but the present
invention is not limited to such Examples.
Examples 1 to 28, Comparative Examples 1 to 17
[0081] In Examples 1 to 28 and Comparative Examples 1 to 17,
respective base oils, thickeners and additives shown below were
used to prepare respective grease compositions having composition
shown in Tables 1 to 6.
[0082] (A) Base Oil
[0083] (A-1) Mineral oil: paraffinic refined mineral oil (kinematic
viscosity at 40.degree. C.: 93.3 mm.sup.2/s; viscosity index: 95;
pour point: -15.degree. C.; flash point: 260.degree. C.)
[0084] (A-2) Polyol ester (POE): ester of pentaerythritol and a
mixed acid of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid
in a mass ratio of 5:5 (kinematic viscosity at 40.degree. C.: 66.7
mm.sup.2/s; viscosity index: 92; pour point: -40.degree. C.; flash
point: 248.degree. C.)
[0085] (A-3) Polyalkylene glycol (PAG): polyoxypropylene in which
both ends were blocked by a methyl group (weight average molecular
weight: 1000; kinematic viscosity at 40.degree. C.: 46.0
mm.sup.2/s; viscosity index: 190; pour point: -45.degree. C.; flash
point: 218.degree. C.)
[0086] (A-4) Poly-.alpha.-olefin (PAO): polymer of 1-dodecene
(kinematic viscosity at 40.degree. C.: 100 mm.sup.2/s; viscosity
index: 140; pour point: -40.degree. C.; flash point: 260.degree.
C.)
Herein, the kinematic viscosity and the viscosity index of each of
the base oils were measured according to JIS K2283, the pour point
thereof was measured according to JIS K2269, and the flash point
thereof was measured according to JIS K2265.
[0087] (B) Thickener
[0088] (B-1) Lithium soap grease: lithium 12-hydroxystearate (10%
by mass) was blended and stirred with any of the base oils,
uniformly dissolved therein at about 200.degree. C. and then
cooled, and additive (C or D) was added thereto at about 80.degree.
C. to provide a grease. This lithium soap grease was allowed to
pass through a roll mill and tested as the grease composition.
[0089] (B-2) Urea grease: one in which
diphenylmethane-4,4'-diisocyanate was dissolved in any of the base
oils (about 80.degree. C.) and one in which cyclohexylamine and
octadecylamine were dissolved in any of the base oils (about
80.degree. C.) were prepared (mass ratio of
diphenylmethane-4,4'-diisocyanate/cyclohexylamine/octadecylamine:
9/6/4), both of them were mixed and stirred for reaction
(160.degree. C., 30 minutes) and cooled, and thereafter an additive
(C or D) was added thereto at about 80.degree. C. to provide a urea
grease (5% by mass as diurea). This urea grease was allowed to pass
through a roll mill and tested as the grease composition.
[0090] (B-3) Lithium complex soap grease: 12-hydroxystearic acid
and azelaic acid, and lithium hydroxide were blended and stirred
with any of the base oils in 10% by mass relative to the total
amount of the grease composition, uniformly dissolved therein at
about 200.degree. C. and then cooled, and additive (C or D) was
added thereto at about 80.degree. C. to provide a grease. This
lithium complex soap grease was allowed to pass through a roll mill
and tested as the grease composition.
[0091] (C) Epoxy Compound
[0092] (C-1) 2-Ethylhexyl glycidyl ether
[0093] (C-2) Dodecyl glycidyl ether
[0094] (C-3) Glycidyl-2,2-dimethyl octanoate
[0095] (C-4) 3,4-Epoxycyclohexylmethyl-3',4'-epoxycyclohexane
carboxylate
[0096] (D) Antiwear Additive
[0097] (D-1) Oxygen-containing compound: glycerol monooleate
[0098] (D-2) Nitrogen-containing compound: oleylamine
[0099] (D-3) Organophosphorus compound: tricresyl phosphate
[0100] (D-4) Organosulfur compound A: dibenzyl disulfide
[0101] (D-5) Organomolybdenum compound A: molybdenum
dialkyldithiophosphate [Mo element content: 8.0% by mass]
[0102] (D-6) Alkaline earth metal compound: overbasic Ca sulfonate,
[TMN (ASTM D2895): 325 mgKOH/g; Ca: 12.7% by mass; S: 2% by
mass]
[0103] (D-7) Organozinc compound: zinc dioctyl dithiophosphate
[0104] (D-8) Solid lubricant: graphite (average particle size: 10
.mu.m)
[0105] (D-9) Organomolybdenum compound B: molybdenum
dialkyldithiocarbamate [Mo element content: 10.0% by mass]
[0106] (D-10) Organosulfur compound B: dioctyl polysulfide [sulfur
element content: 39% by mass]
[0107] With respect to each of the grease compositions in Examples
1 to 28 and Comparative Examples 1 to 17, the following tests were
performed.
[0108] [SRV Test]
[0109] A ball/disc reciprocating kinematic friction/wear test
machine,
[0110] SRV test machine (Optimol Instruments, Instrument SRV), was
used to perform seizure load and wear coefficient measurements
according to ASTM D5706.
[0111] SUJ2 was used for materials of the ball and disc of the SRV
test. The test was started at a temperature of 80.degree. C., an
amplitude of 1 mm, a frequency of 50 Hz and a load of 50 N, and the
load was increased by 100 N every 2 minutes to perform the
operation until seizure occurred (the maximum load set was 2000
N).
[0112] In this test, the seizure load, and the friction coefficient
at each load before the seizure can be measured. Tables 1 to 6 show
the seizure load, and the friction coefficient at a load lower than
the seizure load by 200 N in the test in which each of the grease
compositions was used. Herein, "Unstable" in the column "Friction
coefficient" in Tables means that the friction coefficient varied
between 0.08 and 0.18 and the value could not be read.
[0113] [Oxidation Stability Test]
[0114] A sample pressurized to 755 KPa by an oxygen tank was heated
to 99.degree. C. and the pressure drop after a lapse of 100 hours
was measured according to the grease oxidation stability test
method of JIS K2220. The results obtained are shown in Tables 1 to
3. JIS K2220 defines Class 3 grease for rolling bearing (oxidation
stability is good over a wide temperature range) as having a
reduction in oxygen pressure of 49 KPa or less, and the oxidation
stability of each of the grease compositions can be rated based on
the definition.
TABLE-US-00001 TABLE 1 Comparative Comparative Comparative
Comparative Comparative Example 1 Example 1 Example 2 Example 3
Example 2 Example 4 Example 3 Example 5 Base oil Type A-1 A-1 A-1
A-1 A-1 A-1 A-1 A-1 Content Balance Balance Balance Balance Balance
Balance Balance Balance (% by mass) Thickener (% by mass) B-1 10.0
10.0 10.0 10.0 10.0 10.0 -- -- B-2 -- -- -- -- -- -- 5.0 5.0 Epoxy
compound (% by mass) C-1 0.5 -- 0.5 -- 0.2 -- -- -- C-2 -- -- -- --
-- -- 0.3 -- C-3 -- -- -- -- -- -- -- -- C-4 -- -- -- -- -- -- --
-- Antiwear additive (% by mass) D-1 1.0 -- -- 1.0 -- -- -- -- D-2
-- -- -- -- 0.5 0.5 -- -- D-3 -- -- -- -- -- -- 1.5 1.5 D-4 -- --
-- -- -- -- -- -- D-5 -- -- -- -- -- -- -- -- D-6 -- -- -- -- -- --
-- -- D-7 -- -- -- -- -- -- -- -- D-8 -- -- -- -- -- -- -- -- SRV
test Seizure load (N) 700 200 200 400 700 400 800 500 Friction 0.07
Unstable Unstable 0.10 0.08 0.11 0.10 0.13 coefficient Oxidation
stability test Amount of 35 85 38 75 39 70 25 73 reduction in
oxygen pressure (KPa)
TABLE-US-00002 TABLE 2 Comparative Comparative Comparative
Comparative Example 4 Example 6 Example 5 Example 7 Example 6
Example 8 Example 7 Example 9 Base oil Type A-1 A-1 A-1 A-1 A-1 A-1
A-1 A-1 Content Balance Balance Balance Balance Balance Balance
Balance Balance (% by mass) Thickener (% by mass) B-1 10.0 10.0 --
-- 10.0 10.0 10.0 10.0 B-2 -- -- 5.0 5.0 -- -- -- -- Epoxy compound
(% by mass) C-1 -- -- -- -- 2.0 -- 0.2 -- C-2 -- -- -- -- -- -- --
-- C-3 1.0 -- -- -- -- -- -- -- C-4 -- -- 0.5 -- -- -- -- --
Antiwear additive (% by mass) D-1 -- -- -- -- -- -- -- -- D-2 -- --
-- -- -- -- -- -- D-3 -- -- -- -- -- -- -- -- D-4 1.0 1.0 -- -- --
-- -- -- D-5 -- -- 1.0 1.0 -- -- -- -- D-6 -- -- -- -- 3.0 3.0 --
-- D-7 -- -- -- -- -- -- 0.5 0.5 D-8 -- -- -- -- -- -- -- -- SRV
test Seizure load (N) 700 500 700 500 1100 700 900 500 Friction
0.11 0.13 0.07 0.09 0.08 0.11 0.08 0.11 coefficient Oxidation
stability test Amount of 32 76 35 80 28 92 22 68 reduction in
oxygen pressure (KPa)
TABLE-US-00003 TABLE 3 Comparative Comparative Comparative
Comparative Example 8 Example 10 Example 9 Example 11 Example 10
Example 12 Example 11 Example 13 Base oil Type A-1 A-1 A-2 A-2 A-3
A-3 A-1 A-1 Content Balance Balance Balance Balance Balance Balance
Balance Balance (% by mass) Thickener (% by mass) B-1 10.0 10.0
10.0 10.0 10.0 10.0 10.0 10.0 B-2 -- -- -- -- -- -- -- -- Epoxy
compound (% by mass) C-1 -- -- 0.15 -- 0.1 -- 0.3 -- C-2 0.3 -- --
-- -- -- -- -- C-3 -- -- -- -- -- -- -- -- C-4 -- -- -- -- -- -- --
-- Antiwear additive (% by mass) D-1 -- -- 0.2 0.2 -- -- -- -- D-2
-- -- -- -- -- -- -- -- D-3 -- -- 1.0 1.0 -- -- -- -- D-4 -- -- --
-- 0.5 0.5 -- -- D-5 -- -- -- -- 0.1 0.1 1.0 1.0 D-6 2.0 2.0 -- --
-- -- 2.0 2.0 D-7 1.5 1.5 -- -- -- -- 1.5 1.5 D-8 1.0 1.0 -- -- --
-- -- -- SRV test Seizure load (N) 1500 1100 1100 700 1000 700 1500
1200 Friction 0.07 0.10 0.07 0.10 0.07 0.10 0.06 0.09 coefficient
Oxidation stability test Amount of 20 60 38 75 39 70 21 65
reduction in oxygen pressure (KPa)
TABLE-US-00004 TABLE 4 Example 12 Example 13 Example 14 Example 15
Example 16 Example 17 Example 18 Example 19 Base oil Type A-1 A-1
A-1 A-1 A-1 A-4 A-1 A-1 Content Balance Balance Balance Balance
Balance Balance Balance Balance (% by mass) Thickener (% by mass)
B-1 -- 10.0 -- -- -- -- -- -- B-3 10.0 -- 10.0 10.0 10.0 10.0 10.0
10.0 Epoxy compound (% by mass) C-1 0.5 0.5 -- -- -- 0.5 1.0 0.5
C-2 -- -- 0.5 -- -- -- -- -- C-3 -- -- -- 0.5 -- -- -- -- C-4 -- --
-- -- 0.5 -- -- -- Antiwear additive (% by mass) D-5 1.0 1.0 1.0
1.0 1.0 1.0 5.0 1.0 D-7 1.0 1.0 1.0 1.0 1.0 1.0 5.0 -- D-9 1.0 1.0
1.0 1.0 1.0 1.0 5.0 -- SRV test Seizure load (N) 1500 1400 1400
1400 1400 1500 1700 1200
TABLE-US-00005 TABLE 5 Compar- Compar- Compar- Compar- ative ative
ative ative Exam- Exam- Exam- Exam- Exam- ple 20 ple 14 ple 15 ple
16 ple 17 Base oil Type A-1 A-1 A-1 A-1 A-1 Content Bal- Bal- Bal-
Bal- Bal- (% by mass) ance ance ance ance ance Thickener (% by
mass) B-1 -- -- -- -- 10.0 B-3 10.0 10.0 10.0 10.0 -- Epoxy
compound (% by mass) C-1 0.5 -- 0.5 -- -- C-2 -- -- -- -- -- C-3 --
-- -- -- -- C-4 -- -- -- -- Antiwear additive (% by mass) D-5 --
1.0 -- -- 0.5 D-7 1.0 1.0 -- -- 1.0 D-9 -- 1.0 -- -- 3.0 D-10 --
---- -- -- 1.0 SRV test Seizure 1100 800 400 400 800 load (N)
Friction -- -- -- -- 0.07 coefficient
TABLE-US-00006 TABLE 6 Example 21 Example 22 Example 23 Example 24
Example 25 Example 26 Example 27 Example 28 Base oil Type A-1 A-1
A-1 A-1 A-1 A-2 A-1 A-1 Content Balance Balance Balance Balance
Balance Balance Balance Balance (% by mass) Thickener (% by mass)
B-1 10.0 -- 10.0 10.0 10.0 10.0 10.0 10.0 B-2 -- 10.0 -- -- -- --
-- -- Epoxy compound (% by mass) C-1 0.5 0.5 -- -- -- 0.5 1.0 0.5
C-2 -- -- 0.5 -- -- -- -- -- C-3 -- -- -- 0.5 -- -- -- -- C-4 -- --
-- -- 0.5 -- -- -- Antiwear additive (% by mass) D-5 0.5 0.5 0.5
0.5 0.5 0.5 2.0 -- D-7 1.0 1.0 1.0 1.0 1.0 1.0 3.0 1.0 D-9 3.0 3.0
3.0 3.0 3.0 3.0 5.0 3.0 D-10 1.0 1.0 1.0 1.0 1.0 1.0 3.0 1.0 SRV
test Seizure load (N) 1600 1500 1500 1500 1500 1600 1700 1400
Friction 0.04 0.05 0.05 0.05 0.05 0.04 0.04 0.04 coefficient
INDUSTRIAL APPLICABILITY
[0115] The grease composition of the present invention is a grease
that is significantly improved in terms of stability, lubricity and
friction characteristics and that is excellent in reliability so
that the initial characteristics may be maintained and the effect
of wear-resistance may be kept even under severe lubrication
conditions, as compared with a conventional grease. Accordingly,
the grease composition of the present invention may be suitably
used as a lubricant for various machines, vehicles, driving force
transmission mechanisms and the like that are required to have
anti-wear performance and energy saving performance.
* * * * *