U.S. patent application number 15/029136 was filed with the patent office on 2016-09-08 for lubricating oil 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 Mona Ariyama, Noriko Ayame, Hitoshi Komatsubara.
Application Number | 20160257905 15/029136 |
Document ID | / |
Family ID | 52828222 |
Filed Date | 2016-09-08 |
United States Patent
Application |
20160257905 |
Kind Code |
A1 |
Komatsubara; Hitoshi ; et
al. |
September 8, 2016 |
Lubricating Oil Composition
Abstract
Disclosed is a lubricating oil composition comprising: a
lubricating base oil comprising 0.5% to 70% by mass of an ester
base oil based on the total amount of the lubricating base oil, and
having a kinematic viscosity at 40.degree. C. of 18 to 28
mm.sup.2/s; and an organic molybdenum compound in an amount of 100
to 1000 mass ppm in terms of the molybdenum element based on the
total amount of the lubricating oil composition, wherein the
lubricating oil composition has a kinematic viscosity at 40.degree.
C. of 50 mm.sup.2/s or less.
Inventors: |
Komatsubara; Hitoshi;
(Tokyo, JP) ; Ayame; Noriko; (Tokyo, JP) ;
Ariyama; Mona; (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: |
52828222 |
Appl. No.: |
15/029136 |
Filed: |
October 17, 2014 |
PCT Filed: |
October 17, 2014 |
PCT NO: |
PCT/JP2014/077707 |
371 Date: |
April 13, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2030/02 20130101;
C10M 2205/0206 20130101; C10N 2030/06 20130101; C10M 133/44
20130101; C10M 2219/068 20130101; C10M 169/04 20130101; C10N
2040/04 20130101; C10M 169/044 20130101; C10M 107/02 20130101; C10M
2215/28 20130101; C10M 135/18 20130101; C10N 2010/12 20130101; C10M
2209/086 20130101; C10M 2207/2805 20130101; C10M 2215/223 20130101;
C10M 105/32 20130101; C10M 2227/066 20130101; C10N 2020/02
20130101; C10M 101/02 20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04; C10M 133/44 20060101 C10M133/44; C10M 105/32 20060101
C10M105/32; C10M 135/18 20060101 C10M135/18; C10M 107/02 20060101
C10M107/02; C10M 101/02 20060101 C10M101/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 18, 2013 |
JP |
2013-217600 |
Claims
1. A lubricating oil composition comprising: a lubricating base oil
comprising 0.5% to 70% by mass of an ester base oil based on the
total amount of the lubricating base oil, and having a kinematic
viscosity at 40.degree. C. of 18 to 28 mm.sup.2/s; and an organic
molybdenum compound in an amount of 100 to 1000 mass ppm in terms
of molybdenum element based on the total amount of the lubricating
oil composition, wherein the lubricating oil composition has a
kinematic viscosity at 40.degree. C. 10 of 50 mm.sup.2/s or
less.
2. The lubricating oil composition according to claim 1, further
comprising 2% by mass or more of a copolymer consisting of an
.alpha.-olefin and an ester monomer having a polymerizable
unsaturated bond based on the total amount of the lubricating oil
composition, wherein the weight-average molecular weight of the
copolymer is 2000 to 20000.
3. The lubricating oil composition according to claim 1, further
comprising a boron-containing dispersant in an amount of 100 to 500
mass ppm in terms of boron element based on the total amount of the
lubricating oil composition.
4. The lubricating oil composition according to claim 1, wherein
the lubricating oil composition is used for a hypoid gear.
5. The lubricating oil composition according to claim 1, wherein
the lubricating base oil comprises a synthetic base oil comprising
a poly-.alpha.-olefin.
Description
TECHNICAL FIELD
[0001] The present invention relates to a lubricating oil
composition.
BACKGROUND ART
[0002] In recent years, in order to cope with environmental
problems such as reduction in carbon dioxide emission, the saving
of energy in automobiles, construction machineries, agricultural
machineries, etc., namely, fuel saving has become an urgent task,
and thus, it has been strongly desired that devices such as
engines, transmissions, final drive gears, compressors or hydraulic
systems contribute to such saving of energy. As such, lubricating
oil used in these devices has been required to reduce stirring
resistance and rotational resistance, in comparison to the
conventional oil.
[0003] As a means for fuel saving in transmissions and final drive
gears, reduction in the viscosity of lubricating oil is applied.
For example, among transmissions, automatic transmissions and
continuously variable transmissions for use in automobiles have a
torque converter, a wet clutch, a gear bearing mechanism, an oil
pump, a hydraulic control mechanism and the like, and also, manual
transmissions and final drive gears have a gear bearing mechanism,
and by reducing the viscosity of lubricating oil used in these
devices, the stirring resistance and rotational resistance of such
a torque converter, a wet clutch, a gear bearing mechanism, an oil
pump and the like can he reduced, and the power transmission
efficiency can be improved, so that the improvement of fuel
consumption in automobiles can be achieved.
[0004] However, in order to reduce the viscosity of lubricating oil
and to achieve a high viscosity index, if the viscosity of base oil
is decreased and a large amount of viscosity index improver is
blended into the oil, a reduction in the oil film thickness, which
is competing performance, causes a reduction in extreme pressure
properties and wear resistance, and as a result, seizure and the
like may occur, so that defects and the like would occur in
transmissions, etc. Moreover, if the amounts of a sulfur extreme
pressure agent and a phosphorus-sulfur extreme pressure agent are
increased to improve extreme pressure properties, oxidation
stability would be significantly deteriorated.
[0005] As conventional lubricating oil compositions, lubricating
oil compositions produced by blending various types of additives to
mineral oil- and/or synthetic oil-based lubricating base oil, which
have both fuel saving and the sufficient durability of gears,
bearings, etc. have been proposed (see, for example, Patent
Literatures 1 and 2). However, regarding fuel saving, there has
been still room for improvement even in these conventional
lubricating oil compositions.
CITATION LIST
Patent literature
[0006] Patent Literature 1: JP 2008-208212 A
[0007] Patent Literature 2: JP 2009-249496 A
SUMMARY OF INVENTION
Technical Problem
[0008] The present invention has been made under the aforementioned
circumstances, and it is an object of the present invention to
provide a lubricating oil composition, which has extreme pressure
properties and wear resistance enough to achieve fuel saving, and
reduces a metal-to-metal friction coefficient.
Solution to Problem
[0009] To solve the aforementioned object, the present invention
provides a lubricating oil composition according to [1] to [4]
below, use of the composition according to [5] below, and use of
the composition for the production according to [6] below.
[0010] [1] A lubricating oil composition comprising: a lubricating
base oil comprising 0.5% to 70% by mass of an ester base oil based
on the total amount of the lubricating base oil, and having a
kinematic viscosity at 40.degree. C. of 18 to 28 mm.sup.2/s; and an
organic molybdenum compound in an amount of 100 to 1000 mass ppm in
terms of molybdenum element based on the total amount of the
lubricating oil composition, wherein the lubricating oil
composition has a kinematic viscosity at 40.degree. C. of 50
mm.sup.2/s or less.
[0011] [2] The lubricating oil composition according to [1] above
further comprising 2% by mass or more of a copolymer consisting of
an .alpha.-olefin and an ester monomer having a polymerizable
unsaturated bond, wherein the weight-average molecular weight of
the copolymer is 2000 to 20000.
[0012] [3] The lubricating oil composition according to [1] or [2]
above further comprising a boron-containing dispersant in an amount
of 100 to 500 mass ppm in terms of boron element based on the total
amount of the lubricating oil composition.
[0013] [4] The lubricating oil composition according to any one of
[1] to [3] above, which is used for a hypoid gear.
[0014] [5] Use of the composition as a lubricating oil for a hypoid
gear, wherein the composition comprises: a lubricating base oil
comprising 0.5% to 70% by mass of an ester base oil based on the
total amount of the lubricating base oil, and having a kinematic
viscosity at 40.degree. C. of 18 to 28 mm.sup.2/s; and an organic
molybdenum compound in an amount of 100 to 1000 mass ppm in terms
of the molybdenum element based on the total amount of the
lubricating oil composition, wherein the lubricating oil
composition has a kinematic viscosity at 40.degree. C. of 50
mm.sup.2/s or less.
[0015] [6] Use of the composition for the production of a
lubricating oil for a hypoid gear, wherein the composition
comprises: a lubricating base oil comprising 0.5% to 70% by mass of
an ester base oil based on the total amount of the lubricating base
oil, and having a kinematic viscosity at 40.degree. C. of 18 to 28
mm.sup.2/s; and an organic molybdenum compound in an amount of 100
to 1000 mass ppm in terms of the molybdenum element based on the
total amount of the lubricating oil composition, wherein the
lubricating oil composition has a kinematic viscosity at 40.degree.
C. of 50 mm.sup.2/s or less.
[0016] The term "kinematic viscosity" used in the present invention
means a kinematic viscosity defined according to ASTM D-445. In
addition, the term "viscosity index" used in the present invention
means a viscosity index measured in accordance with JIS K
2283-1993.
Advantageous Effects of Invention
[0017] According to the present invention, there is provided a
lubricating oil composition, which has sufficient extreme pressure
properties and wear resistance, and further reduces a
metal-to-metal friction coefficient. Therefore, when the
lubricating oil composition of the present invention is applied to
an automotive manual transmission, an automatic transmission or a
continuously variable transmission, or to an industrial gear
system, it can achieve fuel saving, while maintaining properties
necessary as a gear oil, and particularly, as a hypoid gear
oil.
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter, preferred embodiments of the present invention
will be described.
[0019] The lubricating oil composition according to the present
embodiment comprises: (A) a lubricating base oil comprising 0.5% to
70% by mass of an ester base oil based on the total amount of the
lubricating base oil, and having a kinematic viscosity at
40.degree. C. of 18 to 28 mm.sup.2/s; and (B) an organic molybdenum
compound in an amount of 100 to 1000 mass ppm in terms of the
molybdenum element based on the total amount of the lubricating oil
composition, wherein the lubricating oil composition has a
kinematic viscosity at 40.degree. C. of 50 mm.sup.2/s or less.
[0020] [Component (A): Lubricating Base Oil]
[0021] The lubricating oil composition of the present embodiment
comprises (A) a lubricating base oil comprising 0.5% to 70% by mass
of an ester base oil based on the total amount of the lubricating
base oil, and having a kinematic viscosity at 40.degree. C. of 18
to 28 mm.sup.2/s.
[0022] The alcohol constituting the ester base oil may be either
monohydric alcohol or polyhydric alcohol (polyol), and the acid
constituting the ester base oil may be either monobasic acid or
polybasic acid. In addition, as long as the ester base oil is a
base oil containing an ester bond, it may also be a complex ester
compound.
[0023] As monohydric alcohols, the monohydric alcohol having
generally 1 to 24, preferably 1 to 12, and more preferably 1 to 8
carbon atoms is used, and such alcohol may be linear or branched,
and may also be saturated or unsaturated. Specific examples of the
alcohol having 1 to 24 carbon atoms include methanol, ethanol,
linear or branched propanol, linear or branched butanol, linear or
branched pentanol, linear or branched hexanol, linear or branched
heptanol, linear or branched octanol, linear or branched nonanol,
linear or branched decanol, linear or branched undecanol, linear or
branched dodecanol, linear or branched tridecanol, linear or
branched tetradecanol, linear or branched pentadecanol, linear or
branched hexadecanol, linear or branched heptadecanol, linear or
branched octadecanol, linear or branched nonadecanol, linear or
branched icosanol, linear or branched henicosanol, linear or
branched tricosanol, linear or branched tetracosanol, and the
mixtures thereof.
[0024] As polyhydric alcohols (polyol), generally a 2- to
10-valent, and preferably a 2- to 6-valent polyhydric alcohol is
used. Specific examples of the 2- to 10-valent polyhydric alcohol
include: divalent alcohols such as ethylene glycol, diethylene
glycol, polyethylene glycol (timer to 15-mer of ethylene glycol),
propylene glycol, dipropylene glycol, polypropylene glycol (trimer
to 15-mer of propylene glycol), 1,3-propanediol, 1,2-propanediol,
1,3-butanediol, 1,4-butanediol, 2-methyl -1,2-propanediol,
2-methyl-1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol,
1,4-pentanediol, 1,5-pentanediol, or neopentyl glycol; polyhydric
alcohols such as glycerin, polyglycerin (dimer to octamer of
glycerin, such as diglycerin, triglycerin, or tetraglycerin),
trimethylolalkane (trimethylolethane, trimethylolpropane,
trimethylolbutane, etc.) and the dimer to octamer thereof,
pentaerythritol and the dimer to tetramer thereof,
1,2,4-butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol,
1,2,3,4-butanetetrol, sorbitol, sorbitan, a sorbitol glycerin
condensate, adonitol, arabitol, xylitol, or mannitol; sugars such
as xylose, arabinose, ribose, rhamnose, glucose, fructose,
galactose, mannose, sorbose, cellobiose, maltose, isomaltose,
trehalose, or sucrose; and the mixtures thereof.
[0025] As monobasic acids, a fatty acid having 2 to 24 carbon atoms
is generally used, and the fatty acid may be linear or branched,
and may also be saturated or unsaturated. Specific examples
include: saturated fatty acids such as acetic acid, propionic acid,
linear or branched butanoic acid, linear or branched pentanoic
acid, linear or branched hexanoic acid, linear or branched
heptanoic acid, linear or branched octanoic acid, linear or
branched nonanoic acid, linear or branched decanoic acid, linear or
branched undecanoic acid, linear or branched dodecanoic acid,
linear or branched tridecanoic acid, linear or branched
tetradecanoic acid, linear or branched pentadecanoic acid, linear
or branched hexadecanoic acid, linear or branched heptadecanoic
acid, linear or branched octadecanoic acid, linear or branched
nonadecanoic acid, linear or branched icosanoic acid, linear or
branched henicosanoic acid, linear or branched docosanoic acid,
linear or branched tricosanoic acid, or linear or branched
tetracosanoic acid; unsaturated fatty acids such as acrylic acid,
linear or branched butenoic acid, linear or branched pentenoic
acid, linear or branched hexenoic acid, linear or branched
heptenoic acid, linear or branched octenoic acid, linear or
branched nonenic acid, linear or branched decenoic acid, linear or
branched undecenoic acid, linear or branched dodecenoic acid,
linear or branched tridecenoic acid, linear or branched
tetradecenoic acid, linear or branched pentadecenoic acid, linear
or branched hexadecenoic acid, linear or branched heptadecenoic
acid, linear or branched octadecenoic acid, linear or branched
nonadecenoic acid, linear or branched icosenoic acid, linear or
branched henicosenoic acid, linear or branched docosenoic acid,
linear or branched tricosenoic acid, or linear or branched
tetracosenoic acid; and the mixtures thereof.
[0026] Examples of the polybasic acid include dibasic acid having 2
to 16 carbon atoms and trimellitic acid. The dibasic acid having 2
to 16 carbon atoms may be linear or branched, and may also be
saturated or unsaturated. Specific examples include ethanedioic
acid, propanedioic acid, linear or branched butanedioic acid,
linear or branched pentanedioic acid, linear or branched
hexanedioic acid, linear or branched heptanedioic acid, linear or
branched octanedioic acid, linear or branched nonanedioic acid,
linear or branched decanedioic acid, linear or branched
undecanedioic acid, linear or branched dodecanedioic acid, linear
or branched tridecanedioic acid, linear or branched
tetradecanedioic acid, linear or branched heptadecanedioic acid,
linear or branched hexadecanedioic acid, linear or branched
hexenedioic acid, linear or branched heptenedioic acid, linear or
branched octenedioic acid, linear or branched nonenedioic acid,
linear or branched decenedioic acid, linear or branched
undecenedioic acid, linear or branched dodecenedioic acid, linear
or branched tridecenedioic acid, linear or branched
tetradecenedioic acid, linear or branched heptadecenedioic acid,
linear or branched hexadecenedioic acid, and the mixtures
thereof.
[0027] The combination of alcohol and acid that form an ester are
arbitrarily selected, and is not particularly limited, and examples
of the ester that can be used in the present invention include the
following esters, and these esters may be used singly or in
combinations of two or more:
[0028] (a) an ester formed from monohydric alcohol and monobasic
acid,
[0029] (b) an ester formed from polyhydric alcohol and monobasic
acid,
[0030] (c) an ester formed from monohydric alcohol and polybasic
acid,
[0031] (d) an ester formed from polyhydric alcohol and polybasic
acid,
[0032] (e) a mixed ester formed from a mixture of monohydric
alcohol and polyhydric alcohol, and polybasic acid,
[0033] (f) a mixed ester formed from polyhydric alcohol, and a
mixture of monobasic acid and polybasic acid, and
[0034] (g) a mixed ester formed from a mixture of monohydric
alcohol and polyhydric alcohol, monobasic acid, and polybasic
acid,
[0035] Among these esters, (c) the ester formed from monohydric
alcohol and polybasic acid is preferable because it is excellent in
abrasion resistance and oxidation stability, and a dibasic acid
ester that is an ester formed from monohydric alcohol and dibasic
acid is more preferable.
[0036] The content of the ester base oil is 0.5% to 70% by mass,
preferably 1% by mass or more, more preferably 2% by mass or more,
and even more preferably 3% by mass or more, based on the total
amount of the lubricating base oil. Also, it is preferably 60% by
mass or less, and more preferably 55% by mass or less. If the
content of the ester base oil is 0.5% by mass or more, the
lubricating base oil tends to be excellent in extreme pressure
properties, wear resistance, seizure resistance, and abrasion
resistance. In addition, if the content of the ester base oil is
70% by mass or less, the lubricating base oil tends to be excellent
in oxidation stability.
[0037] The kinematic viscosity of the ester base oil at 40.degree.
C. is not particularly limited, and it is preferably 5 mm.sup.2/s
or more, more preferably 6 mm.sup.2/s or more, and even more
preferably 7 mm.sup.2/s or more. Also, it is preferably 50
mm.sup.2/s or less, more preferably 30 mm.sup.2/s or less, and even
more preferably 20 mm.sup.2/s or less. If the kinematic viscosity
at 40.degree. C. is 5 mm.sup.2/s or more, or 50 mm.sup.2/s or less,
the lubricating base oil tends to be excellent in extreme pressure
properties, wear resistance, and seizure resistance.
[0038] The viscosity index of the ester base oil is not
particularly limited, and it is preferably 125 or more, more
preferably 130 or more, and even more preferably 135 or more. If
the viscosity index is 125 or more, the lubricating base oil tends
to be excellent in low temperature fluidity.
[0039] The pour point of the ester base oil is not particularly
limited, and it is preferably -30.degree. C. or lower, more
preferably -50.degree. C. or lower, even more preferably
-60.degree. C. or lower, and particularly preferably -70.degree. C.
or lower.
[0040] The flash point of the ester base oil is not particularly
limited, and it is preferably 200.degree. C. or higher, more
preferably 250.degree. C. or higher, and even more preferably
300.degree. C. or higher.
[0041] The lubricating base oil according to the present embodiment
may comprise base oil components other than the ester base oil, as
long as the content of the ester base oil is 0.5% to 70% by mass
based on the total amount of the lubricating base oil. The base oil
components other than the ester base oil are not particularly
limited, and base oil used in ordinary lubricating oil can be used.
Specific examples of the oil components other than the ester base
oil that can be used herein include mineral oil base oil, synthetic
base oil, and a mixture obtained by mixing two or more types of
base oils selected from the aforementioned base oils at any given
ratio.
[0042] Examples of the mineral oil base oil include: paraffinic and
naphthenic mineral oil base oils, which are obtained by purifying
a. lubricating oil fraction, which has been obtained by subjecting
crude oil to atmospheric distillation and vacuum distillation, by
applying purification treatments, such as solvent deasphalting,
solvent extraction, hydrogenolysis, solvent dewaxing, catalytic
dewaxing, hydrorefining, sulfuric acid washing, or clay treatment,
alone or appropriately in combinations of two or more; and base
oils produced by subjecting normal paraffin, isoparaffin and
petroleum wax to catalytic dewaxing. It is to be noted that these
base oils may be used singly or in combinations of two or more at
any given ratio.
[0043] From the viewpoint of reduction in viscosity and the content
of sulfur, the mineral oil base oil is preferably base oil
classified into Group II or Group III in Base Stock Categories of
API (American Petroleum Institute), and more preferably base oil
classified into Group III.
[0044] Examples of the synthetic base oil include a
poly-.alpha.-olefin or a hydride thereof, an isobutene oligomer or
a hydride thereof, isoparaffin, alkylbenzene, alkylnaphthalene,
polyoxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether,
and base oil produced by subjecting wax produced by the
Fischer-Tropsch process to catalytic dewaxing.
[0045] The synthetic base oil is preferably a poly-.alpha.-olefin,
or base oil produced by subjecting wax produced by the
Fischer-Tropsch process to catalytic dewaxing. Specific examples of
the poly-.alpha.-olefin include .alpha.-olefin oligomers or
cooligomers having 2 to 32, and preferably 6 to 16 carbon atoms
(e.g., a 1-octene oligomer, a 1-decene oligomer, a 1-dodecene
oligomer, an ethylene-propylene cooligomer, etc.), and the hydrides
thereof.
[0046] A method for producing a poly-.alpha.-olefin is not
particularly limited, and an example of the production method is
polymerization of an .alpha.-olefin in the presence of a
polymerization catalyst comprising a complex with aluminum
trichloride, boron trifluoride, or boron trifluoride and water,
alcohol (e.g., ethanol, propanol or butanol), carboxylic acid, or
ester (e.g., ethyl acetate or ethyl propionate), such as a
Friedel-Crafts catalyst.
[0047] The kinematic viscosity of the lubricating base oil at
40.degree. C. is 18 to 28 mm.sup.2/s, preferably 20 mm.sup.2/s or
more, and more preferably 22 mm.sup.2/s or more. Also, it is
preferably 27 mm.sup.2/s or less, and more preferably 26 mm.sup.2/s
or less. By setting the kinematic viscosity at 40.degree. C. to 18
mm.sup.2/s or more, an oil film is sufficiently formed, and thus,
it becomes possible to obtain a lubricating oil composition, which
is excellent in lubricity and has a smaller evaporation loss of the
base oil under high-temperature conditions. On the other hand, by
setting the kinematic viscosity at 40.degree. C. to 28 mm.sup.2/s
or less, a lubricating oil composition becomes excellent in low
temperature fluidity and fluid resistance thereof is decreased, and
thus, it becomes possible to obtain a lubricating oil composition
having smaller rotational resistance.
[0048] The kinematic viscosity of the lubricating base oil at
100.degree. C. is not particularly limited, and it is preferably 1
mm.sup.2/s or more, more preferably 3 mm.sup.2/s or more, and even
more preferably 4 mm.sup.2/s or more. Also, it is preferably 10
mm.sup.2/s or less, more preferably 8 mm.sup.2/s or less, and even
more preferably 6 mm.sup.2/s or less. By setting the kinematic
viscosity at 100.degree. C. to 1 mm.sup.2/s or more, an oil film is
sufficiently formed, and thus, it becomes possible to obtain a
lubricating oil composition, which is excellent in lubricity and
has a smaller evaporation loss of the base oil under
high-temperature conditions. On the other hand, by setting the
kinematic viscosity at 100.degree. C. to 10 mm.sup.2/s or less, it
becomes possible to obtain a lubricating oil composition, which is
excellent in low temperature fluidity.
[0049] The viscosity index of the lubricating base oil is not
particularly limited, and it is preferably 120 or more, more
preferably 125 or more, and even more preferably 130 or more. By
setting the viscosity index to 120 or more, a lubricating oil
composition, which exhibits good viscosity properties in a
temperature range from a low temperature to a high temperature, and
is excellent in oxidation stability.
[0050] [Component (B): Organic Molybdenum Compound]
[0051] The lubricating oil composition according to the present
embodiment comprises, as a friction modifier, an organic molybdenum
compound in an amount of 100 to 1000 mass ppm in terms of the
molybdenum element based on the total amount of the lubricating oil
composition. By combining the component (B) with the component (A),
a metal-to-metal friction coefficient can be reduced, and fuel
saving can be enhanced.
[0052] Examples of the organic molybdenum compound according to the
present embodiment include: organic molybdenum compound containing
sulfur, such as molybdenum dithiophosphate or molybdenum
dithiocarbamate (MoDTC); complexes formed from molybdenum compounds
(e.g., molybdenum oxides such as molybdenum dioxide or molybdenum
trioxide, molybdic acids such as orthomolybdic acid, paramolybdic
acid or polysulfurized molybdic acid, the metal salts of these
molybdic acids, molybdates such as ammonium salt, molybdenum
sulfides such as molybdenum disulfide, molybdenum trisulfide,
molybdenum pentasulfide or molybdenum polysulfide, sulfurized
molybdic acids, the metal salts or amine salts of the sulfurized
molybdic acids, halogenated molybdenums such as molybdenum
chloride, etc.), and sulfur-containing organic compounds (e.g.,
alkyl(thio)xanthate, thiaziazole, mercaptothiadiazole,
thiocarbonate, tetrahydrocarbylthiuramdisulfide,
bis(di(thio)hydrocarbyldithiophosphonate)disulfide, organic
(poly)sulfide, and sulfide ester, etc.) or other organic compounds;
and complexes formed from sulfur-containing molybdenum compounds
such as the above-mentioned molybdenum sulfides or sulfurized
molybdenum acids and alkenyl succinimides.
[0053] Moreover, as such an organic molybdenum compound, an organic
molybdenum compound, which does not contain sulfur as a
constitutional element, can be used. Specific examples of the
organic molybdenum compound, which does not contain sulfur as a
constitutional element, include a molybdenum-amine complex, a
molybdenum-succinimide complex, the molybdenum salt of organic
acid, and the molybdenum salt of alcohol, and among others, a
molybdenum-amine complex, the molybdenum salt of organic acid, and
the molybdenum salt of alcohol are preferable.
[0054] In the lubricating oil composition according to the present
embodiment, the content of the organic molybdenum compound is 100
to 1000 mass ppm, preferably 200 mass ppm or more, and more
preferably 300 mass ppm or more, in terms of the molybdenum element
based on the total amount of the lubricating oil composition. Also,
it is preferably 900 mass ppm or less, and more preferably 800 mass
ppm or less. If the content of the organic molybdenum compound is
100 mass ppm or more, the lubricating oil composition tends to be
excellent in wear resistance and abrasion resistance, and if the
content is 1000 mass ppm or less, the lubricating oil composition
tends to be excellent in seizure resistance. It is to be noted that
the amount of the organic molybdenum compound in terms of the
molybdenum element can be obtained, for example, by an ICP
elemental analysis method or the like.
[0055] The lubricating oil composition according to the present
embodiment may further comprise, as a viscosity modifier, a
copolymer consisting of an .alpha.-olefin and an ester monomer
having a polymerizable unsaturated bond, in an amount of 2% by mass
or more based on the total amount of the lubricating oil
composition. The weight-average molecular weight of the above
described copolymer is preferably 2000 to 20000. By allowing the
present lubricating oil composition to further comprise such a
copolymer, the oil film retentivity and extreme pressure properties
of the lubricating oil composition can be further improved.
[0056] The ester monomer having a polymerizable unsaturated bond is
not particularly limited, as long as it is a compound having a
polymerizable unsaturated bond and an ester bond, and the ester
monomer is preferably an .alpha.,.beta.-ethylenically unsaturated
dicarboxylic acid diester, which is a diester body of unsaturated
dicarboxylic acid, in which the .alpha. carbon and .beta. carbon of
at least one carboxy group form an ethylenically unsaturated bond
(namely, a C.dbd.C double bond). Herein, the
.alpha.,.beta.-ethylenically unsaturated dicarboxylic acid is not
limited to a compound in which an .alpha. carbon and a .beta.
carbon form an ethylenically unsaturated bond in both carboxy
groups and the .alpha.,.beta.-ethylenically unsaturated bond is
present in the main chain, such as maleic acid, fumaric acid,
citraconic acid or mesaconic acid, but the
.alpha.,.beta.-ethylenically unsaturated dicarboxylic acid used
herein means a concept including a compound in which an .alpha.
carbon and a .beta. carbon form an ethylenically unsaturated bond
in only one carboxy group, such as glutaconic acid, or a concept
including a compound in which the .alpha.,.beta.-ethylenically
unsaturated bond is found in the side chain, such as itaconic
acid.
[0057] The structure of the copolymer consisting of an
.alpha.-olefin and an ester monomer having a polymerizable
unsaturated bond is not particularly limited, as long as its
weight-average molecular weight is 2000 to 20000. In addition, a
method for producing the copolymer is not particularly limited,
either, and a copolymer produced by a known method can be used.
[0058] The weight-average molecular weight (Mw) of the copolymer
consisting of an .alpha.-olefin and an ester monomer having a
polymerizable unsaturated bond is 2000 to 20000, preferably 4000 or
more, and more preferably 6000 or more. Also, the weight-average
molecular weight is preferably 15000 or less, and more preferably
12000 or less. By setting the weight-average molecular weight at
2000 to 20000, it becomes possible to improve oil film retentivity
and extreme pressure properties.
[0059] It is to be noted that the term "weight-average molecular
weight" used herein means a weight-average molecular weight
relative to standard polystyrene, which is measured using, in
series, two columns of GMHHR-M (7.8 mm ID.times.30 cm) manufactured
by Tosoh Corporation in the 150-C ALC/GPC device manufactured by
Waters, using tetrahydrofuran as a solvent, and also using a
refractive index (RI) detector under conditions of a temperature of
23.degree. C., a flow rate of 1 mL/min., a sample concentration of
1% by mass, and a sample injection rate of 75 .mu.L.
[0060] In the lubricating oil composition according to the present
embodiment, the content of the copolymer is preferably 2% by mass
or more, more preferably 2.5% by mass or more, and even more
preferably 3.5% by mass or more, based on the total amount of the
lubricating oil composition. By setting the content of the
copolymer to 2% by mass or more, the present lubricating oil
composition tends to be excellent in extreme pressure properties
and wear resistance. On the other hand, the upper limit of the
content is not particularly limited, and it is preferably 25% by
mass or less, more preferably 24% by mass or less, and even more
preferably 22% by mass or less. By setting the content of a
component (D) to 25% by mass or less, the lubricating oil
composition tends to exhibit sufficient extreme pressure
properties, wear resistance, seizure resistance, abrasion
resistance and oxidation stability.
[0061] The lubricating oil composition according to the present
embodiment may further comprise a boron-containing dispersant in an
amount of 100 to 500 mass ppm in terms of the boron element based
on the total amount of the lubricating oil composition. Thereby,
the oil film retentivity and extreme pressure properties of the
present lubricating oil composition can be further improved.
[0062] The boron-containing dispersant is any given ashless
dispersant that has been borated. Examples of the ashless
dispersant include a nitrogen-containing compound having at least
one linear or branched alkyl group or alkenyl group having 40 to
400 carbon atoms in the molecule thereof, or a derivative thereof,
and a modified product of alkenyl succinimide. One or more types
arbitrarily selected from these products may be blended into the
lubricating oil composition.
[0063] It is to be noted that the succinimide includes, what is
called, a mono-type succinimide represented by the following
formula (3), in which succinic anhydride is added to one end of
polyamine, and what is called, a bis-type succinimide represented
by the following formula (4), in which succinic anhydride is added
to both ends of polyamine.
##STR00001##
[0064] In the above formula (3), R.sup.9 represents an alkyl group
or alkenyl group having 40 to 400 carbon atoms, and preferably an
alkyl group or alkenyl group having 60 to 350 carbon atoms; and p
represents an integer of 1 to 5, and preferably of 2 to 4.
[0065] In the above formula (4), R.sup.10 and R.sup.11 may be the
same or different, and each represent an alkyl group or alkenyl
group having 40 to 400 carbon atoms, preferably an alkyl group or
alkenyl group having 60 to 350 carbon atoms, and preferably, each
represent a polybutenyl group; and q represents an integer of 0 to
4, and preferably of 1 to 3.
[0066] The lubricating oil composition according to the present
embodiment may comprise either one of the mono-type and bis-type
succinimides, or may also comprise both of them.
[0067] A method for producing a succinimide is not particularly
limited, and the succinimide can be obtained, for example, by
allowing alkyl succinic acid or alkenyl succinic acid, which has
been obtained by reacting a compound having an alkyl group or
alkenyl group having 40 to 400 carbon atoms with maleic anhydride
at a temperature of 100.degree. C. to 200.degree. C., to react with
polyamine. Specific examples of the polyamine include
diethylenetriamine, triethylenetetramine, tetraethylenepentamine,
and pentaethylenehexamine.
[0068] In the lubricating oil composition according to the present
embodiment, the content of the boron-containing dispersant is
preferably 100 to 500 mass ppm, more preferably 150 mass ppm or
more, and even more preferably 200 mass ppm or more, in terms of
the boron element based on the total amount of the lubricating oil
composition. Also, it is more preferably 450 mass ppm or less, and
even more preferably 400 mass ppm or less. If the content of the
boron-containing dispersant in the lubricating oil composition is
100 mass ppm or more, the present lubricating oil composition tends
to be excellent in extreme pressure properties, wear resistance,
seizure resistance, and abrasion resistance. Also, if the content
of the boron-containing dispersant in the lubricating oil
composition is 500 mass ppm or less, the present lubricating oil
composition tends to be excellent in wear resistance. It is to be
noted that the amount of the boron-containing dispersant in terms
of the boron element can be obtained, for example, by an ICP
elemental analysis method or the like.
[0069] In order to improve performance, the lubricating oil
composition according to the present embodiment may further
comprise any given additives, which are commonly used in
lubricating oil, depending on purpose. Examples of such additives
include viscosity modifiers other than the above described
copolymer, metallic detergents, ashless dispersants other than
boron-containing dispersants, wear inhibitors (or extreme pressure
agents), antioxidants, corrosion inhibitors, rust inhibitors,
demulsifiers, metal deactivators, defoaming agents, and friction
modifiers other than the component (B).
[0070] Specific examples of the viscosity modifier other than the
above described copolymer include viscosity modifiers containing a
non-dispersed or dispersed ester group, such as a non-dispersed or
dispersed poly(meth)acrylate viscosity modifier, a non-dispersed or
dispersed olefin-(meth)acrylate copolymer viscosity modifier, a
styrene-maleic anhydride ester copolymer viscosity modifier, and
the mixtures thereof; and among others, a non-dispersed or
dispersed poly(meth)acrylate viscosity modifier is preferable. In
particular, a non-dispersed or dispersed polymethacrylate viscosity
modifier is preferable.
[0071] Other examples of the viscosity modifier other than the
above described copolymer include a non-dispersed or dispersed
ethylene-.alpha.-olefin copolymer or a hydride thereof,
polyisobutylene or a hydride thereof, a styrene-diene hydrogenated
copolymer, and polyalkylstyrene.
[0072] Examples of the metallic detergent include a sulfonate
detergent, a salicylate detergent and a phenate detergent, and any
one of normal salt, basic normal salt, and perbasic salt with
alkaline metal or alkaline earth metal can be blended. Upon the
use, one or two or more types, which are arbitrarily selected from
these substances, can be blended into the lubricating oil
composition.
[0073] As ashless dispersants other than the boron-containing
dispersant, any given non-boron ashless dispersants, which are used
in lubricating oil, can be used, and examples of such an ashless
dispersant include a mono- or bis-succinimide having at least one
linear or branched alkyl group or alkenyl group having 40 to 400
carbon atoms in the molecule thereof, a benzylamine having at least
one alkyl group or alkenyl group having 40 to 400 carbon atoms in
the molecule thereof, a polyamine having at least one alkyl group
or alkenyl group having 40 to 400 carbon atoms in the molecule
thereof, and the modified products thereof, which are prepared by
using carboxylic acid, phosphoric acid or the like. Upon the use,
one or two or more types, which are arbitrarily selected from these
substances, can be blended into lubricating oil composition.
[0074] As wear inhibitors (or extreme pressure agents), any given
wear inhibitors and/or extreme pressure agents, which are used in
lubricating oil, can be used. For example, sulfur-based,
phosphorus-based, and sulfur-phosphorus-based extreme pressure
agents and the like can be used, and specific examples of such an
extreme pressure agent include zinc dialkyldithiophosphate (ZnDTP),
phosphite esters, thiophosphite esters, dithiophosphite esters,
trithiophosphite esters, phosphoric acid esters, thiophosphoric
acid esters, dithiophosphoric acid esters, trithiophosphoric acid
esters, the amine salts thereof, the metal salts thereof, the
derivatives thereof, dithiocarbamate, zinc dithiocarbamate, MoDTC,
disulfides, polysulfides, sulfurized olefins, and sulfurized oils
and fats. Among these substances, addition of sulfur-based extreme
pressure agents is preferable, and sulfurized oils and fats are
particularly preferable.
[0075] Examples of the antioxidant include ashless antioxidants
such as phenolic ashless antioxidants or amine-based ashless
antioxidants, and metallic antioxidants such as copper-based or
molybdenum-based antioxidants. Specific examples of the phenolic
ashless antioxidant include
4,4'-methylenebis(2,6-di-tert-butylphenol) and
4,4'-bis(2,6-di-tert-butylphenol; and examples of the amine-based
ashless antioxidant include phenyl-.alpha.-naphthylamine,
alkylphenyl-.alpha.-naphthylamine, and dialkyldiphenylamine.
[0076] Examples of the corrosion inhibitor include
benzotriazole-based, tolyltriazole-based, thiadiazole-based, and
imidazole-based compounds.
[0077] Examples of the rust inhibitor include petroleum sulfonate,
alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl
succinic acid ester, and polyhydric alcohol ester.
[0078] Examples of the demulsifier include polyalkylene
glycol-based nonionic surfactants such as polyoxyethylene alkyl
ether, polyoxyethylene alkylphenyl ether, or polyoxyethylene
alkylnaphthyl ether.
[0079] Examples of the metal deactivator include imidazoline, a
pyrimidine derivative, alkylthiadiazole, mercaptobenzothiazole,
benzotriazole or a derivative thereof, 1,3,4-thiadiazole
polysulfide, 1,3,4-thiadiazolyl-2,5-bisdialkyldithiocarbamate,
2-(alkylthio)benzoimidazole, and
.beta.-(o-carboxybenzylthio)propionitrile.
[0080] Examples of the defoaming agent include silicone oil, an
alkenyl succinic acid derivative, an ester of polyhydroxy aliphatic
alcohol and a long chain fatty acid, and an ester of methyl
salicylate and o-hydroxybenzyl alcohol, of which kinematic
viscosity at 25.degree. C. is 1000 to 100000 mm.sup.2/s,
respectively.
[0081] Examples of the friction modifier other than the component
(B) include ashless friction modifiers, and any given compounds,
which are generally used as ashless friction modifiers for
lubricating oil, can be used, and examples of such an ashless
friction modifier include amine-based, imide-based, fatty acid
ester-based, fatty acid amide-based, fatty acid-based, aliphatic
alcohol-based, and aliphatic ether-based ashless friction
modifiers, each of which has at least one hydrocarbon group having
6 to 30 carbon atoms, preferably at least one alkyl group or
alkenyl group, and particularly preferably at least one linear
alkyl group or linear alkenyl group having 6 to 30 carbon atoms, in
the molecule thereof.
[0082] When these additives are contained in the lubricating oil
composition according to the present embodiment, the content of
each additive is preferably 0.01% to 20% by mass based on the total
amount of the lubricating oil composition.
[0083] The kinematic viscosity of the lubricating oil composition
according to the present embodiment at 40.degree. C. is 50
mm.sup.2/s or less, preferably 48 mm.sup.2/s or less, and more
preferably 45 mm.sup.2/s or less. By setting the kinematic
viscosity at 40.degree. C. to 50 mm.sup.2/s or less, necessary low
temperature fluidity and sufficient fuel savings tend to be
obtained. Moreover, the lower limit of the kinematic viscosity of
the lubricating oil composition according to the present embodiment
at 40.degree. C. is not particularly limited, and it is preferably
20 mm.sup.2/s or more, more preferably 30 mm.sup.2/s or more, and
even more preferably 35 mm.sup.2/s or more. By setting the
kinematic viscosity at 40.degree. C. to 20 mm.sup.2/s or more, the
present lubricating oil composition tends to be excellent in oil
film retentivity and evaporativity at lubrication sites.
[0084] Since the lubricating oil composition according to the
present embodiment has extreme pressure properties and wear
resistance, which are sufficient for achieving fuel saving, and is
further capable of reducing a metal-to-metal friction coefficient,
it can be preferably used as a gear oil for an automotive manual
transmission, an automatic transmission or a continuously variable
transmission, or for an industrial gear system, and in particular,
as a hypoid gear oil for the driving systems of automobiles and
railway vehicles.
EXAMPLES
[0085] Hereinafter, the present invention will be more specifically
described in the following examples. However, these examples are
not intended to limit the scope of the present invention.
Examples 1 to 18 and Comparative Examples 1 to 4
[0086] As shown in Table 1 and Table 2, the lubricating oil
compositions of Examples 1 to 18 and Comparative Examples 1 to 4
were prepared, respectively. With regard to the obtained
lubricating oil compositions, their extreme pressure properties,
wear resistance, seizure resistance, abrasion resistance, and
oxidation stability were measured, and the results are shown in
Table 1 and Table 2.
[0087] Details of individual components shown in Table 1 and Table
2 are as follows.
[0088] Base oil A-1: poly-.alpha.-olefin [Group IV, 40.degree. C.
kinematic viscosity: 19 mm.sup.2/s, 100.degree. C. kinematic
viscosity: 4.1 mm.sup.2/s, viscosity index: 126, pour point:
-66.degree. C., flash point: 220.degree. C.]
[0089] Base oil A-2: poly-.alpha.-olefin [Group IV, 40.degree. C.
kinematic viscosity: 30.3 mm.sup.2/s, 100.degree. C. kinematic
viscosity: 5.9 mm.sup.2/s, viscosity index: 142, pour point:
<-54.degree. C., flash point: 246.degree. C.]
[0090] Base oil A-3: poly-.alpha.-olefin [Group IV, 40.degree. C.
kinematic viscosity: 48 mm.sup.2/s, 100.degree. C. kinematic
viscosity: 8.0 mm.sup.2/s, viscosity index: 139, pour point:
-48.degree. C., flash point: 260.degree. C.]
[0091] Base oil A-4: poly-.alpha.-olefin [Group IV, 40.degree. C.
kinematic viscosity: 396 mm.sup.2/s, 100.degree. C. kinematic
viscosity: 39 mm.sup.2/s, viscosity index: 147, pour point:
-36.degree. C., flash point: 281.degree. C.]
[0092] Base oil A-5: hydrorefined mineral oil [Group III,
40.degree. C. kinematic viscosity: 33.97 mm.sup.2/s, 100.degree. C.
kinematic viscosity: 6.208 mm.sup.2/s, viscosity index: 133, sulfur
content: less than 10 mass ppm, % C.sub.P: 80.6, % C.sub.N: 19.4, %
C.sub.A: 0]
[0093] Base oil B-1: dibasic acid ester [Group V, azelaic
acid+2-ethylhexanol, 40.degree. C. kinematic viscosity: 10.3
mm.sup.2/s, 100.degree. C. kinematic viscosity: 2.9 mm.sup.2/s,
viscosity index: 138, pour point: -72.degree. C., flash point:
220.degree. C.]
[0094] Organic molybdenum compound F-1: molybdenum dithiocarbamate
(MoDTC) [amount in terms of the molybdenum element: 10% by
mass]
[0095] Boron-containing dispersant G-1: borated succinimide [amount
in terms of the boron element: 2.0% by mass, amount in terms of
nitrogen element: 2.3% by mass, weight-average molecular weight:
1000]
[0096] Non-boron dispersant H-1: succinimide [amount in terms of
nitrogen element: 2.3 by mass, weight-average molecular weight:
1000]
[0097] Performance additive C-1: an additive package comprising a
phosphorus wear inhibitor, a sulfur extreme pressure agent, a metal
deactivator, a friction modifier, a defoaming agent, etc., [amount
in terms of phosphorus element: 1.40% by mass, amount in terms of
sulfur element: 22.9% by mass]
[0098] Viscosity modifier J-1: a copolymer of an .alpha.-olefin and
an .alpha.,.beta.-ethylenically unsaturated dicarboxylic acid
diester [weight-average molecular weight: 10000]
[0099] Viscosity modifier J-2: a copolymer of an .alpha.-olefin and
an .alpha.,.beta.-ethylenically unsaturated dicarboxylic acid
diester [weight-average molecular weight: 7000]
[0100] Viscosity modifier J-3: an oligomer of ethylene and
.alpha.-olefin [number-average molecular weight: 3700]
[0101] The amount of the organic molybdenum compound in terms of
the molybdenum element, the amount of the boron-containing
dispersant in terms of the boron element, the amount of the
performance additive in terms of phosphorus element, and the amount
of the performance additive in terms of sulfur element were
obtained by an ICP elemental analysis method.
[0102] (1) Extreme Pressure Property Test
[0103] In accordance with ASTM D 2596, using a high speed four-ball
tester, the maximum non-seizure load (LNSL) at 1800 rotation of
each lubricating oil composition was measured. In the present test,
it means that the larger the maximum non-seizure load, the better
the extreme pressure properties that can be achieved.
[0104] (2) Wear Resistance Test
[0105] A four-ball test (ASTM D 4172) was carried out under the
below-mentioned conditions, and a wear scar diameter (mm) was then
measured, so that wear resistance was evaluated. In the present
test, it means that the smaller the wear scar diameter, the better
the wear resistance that can be achieved.
[0106] Load: 800 N
[0107] Number of rotations: 1800 rpm
[0108] Temperature: 80.degree. C.
[0109] Testing time: 30 minutes
[0110] (3) Seizure Resistance Test
[0111] Using a Falex Tester described in ASTM D 3233, a seizure
load was measured, and seizure resistance was evaluated. This
seizure resistance indicates an extreme pressure property between
steels. Conditions for the test are described below. In the present
test, it means that the larger the seizure load, the better the
seizure resistance that can be achieved.
[0112] Temperature: 110.degree. C.
[0113] Number of rotations: 290 rpm
[0114] (4) Abrasion Resistance Test
[0115] Using a Block on Ring Tester (LFW-1) described in ASTM D
2174, a friction coefficient was measured under the below-mentioned
test conditions. Moreover, in the present test, such a friction
coefficient was obtained from both a new oil of the lubricating oil
composition and a degraded oil thereof, which had been obtained by
subjecting the lubricating oil to the after-mentioned oxidation
stability test at 135.degree. C. for 48 hours. In the present test,
it means that the smaller the friction coefficient, the better the
abrasion resistance that can be achieved.
[0116] Ring: Falex S-10 Test Ring (SAE4620 Steel)
[0117] Block: Falex H-60 Test Block (SAE01 Steel)
[0118] Oil temperature: 90.degree. C.
[0119] Load: 222-3113 N
[0120] Slip velocity: 0.5 m/s
[0121] (5) Oxidation Stability Test
[0122] In accordance with JIS K 2514 4. (a method for testing the
oxidation stability of lubricating oil for internal combustion
engines), the test was carried out under the below-mentioned
conditions, and an acid value increase was measured. In the present
test, it means that the smaller the acid value increase, the better
the oxidation stability that can be achieved.
[0123] Temperature: 135.degree. C.
[0124] Testing time: 96 hours
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4
Example 5 Example 6 Example 7 Example 8 Example 9 Base oil A-1 % by
mass -- 40 32 -- -- -- -- -- -- Base oil A-2 % by mass 80 59 63 --
-- -- 80 80 80 Base oil A-3 % by mass -- -- -- 40 -- -- -- -- --
Base oil A-4 % by mass -- -- -- 10 30 -- -- -- -- Base oil A-5 % by
mass -- -- -- -- -- 80 -- -- -- Base oil B-1 % by mass 20 1 5 50 70
20 20 20 20 Base oil (mixture) kinematic viscosity (40.degree. C.)
mm.sup.2/s 23.72 24.66 24.41 23.45 22.65 25.83 23.72 23.72 23.72
(100.degree. C.) mm.sup.2/s 5.03 5.03 5.02 5.05 5.05 5.22 5.03 5.03
5.03 Base oil (mixture) viscosity index 144 134 136 149 158 138 144
144 144 Additive composition (based on total amount of composition)
Organic molybdenum compound F-1 % by mass 0.5 (500) 0.5 (500) 0.5
(500) 0.5 (500) 0.5 (500) 0.5 (500) 0.1 (100) 0.2 (200) 0.7 (700)
(amount in terms of the molybdenum element) mass ppm
Boron-containing dispersant G-1 % by mass 1.0 (200) 1.0 (200) 1.0
(200) 1.0 (200) 1.0 (200) 1.0 (200) 1.0 (200) 1.0 (200) 1.0 (200)
(amount in terms of boron element) mass ppm Non-boron dispersant
II-1 % by mass -- -- -- -- -- -- -- -- -- Performance additive C-1
% by mass 9.0 9.0 9.0 9.0 9.0 9.0 9.0 9.0 9.0 Viscosity modifier
J-1 % by mass 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 Viscosity
modifier J-2 % by mass -- -- -- -- -- -- -- -- -- Viscosity
modifier J-3 % by mass 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7 4.7
Kinematic viscosity (40.degree. C.) mm.sup.2/s 40.0 41.1 40.9 39.7
38.9 43.1 40.0 40.0 40.0 High speed four-ball test 1800 rpm LNSL N
981 981 981 1236 1236 981 981 981 981 Wear scar diameter mm 0.93
0,96 0.95 0.85 0.80 0.97 0.97 0.95 0.92 Falex seizure test N 4893
4671 4893 6895 7918 4715 5382 5249 4671 IFW-1 test (friction
coefficient) (New oil) 90.degree. C. 0.089 0.098 0.094 0.087 0.088
0.091 0.091 0.090 0.090 (Degraded oil) 90.degree. C. 0.030 0.045
0.040 0.031 0.035 0.033 0.046 0.041 0.031 Oxidation stability
(ISOT) (Acid value increase) mgKOH/g 2.44 2.04 2.11 2.72 2.89 2.81
2.41 2.41 2.51 Example Example Example Example Example 10 11
Example 12 13 Example 14 15 Example 16 17 Example 18 Base oil A-1 %
by mass -- -- -- -- -- -- -- -- -- Base oil A-2 % by mass 80 80 80
80 80 80 80 80 80 Base oil A-3 % by mass -- -- -- -- -- -- -- -- --
Base oil A-4 % by mass -- -- -- -- -- -- -- -- -- Base oil A-5 % by
mass -- -- -- -- -- -- -- -- -- Base oil B-1 % by mass 20 20 20 20
20 20 20 20 20 Base oil (mixture) kinematic viscosity (40.degree.
C.) mm.sup.2/s 23.72 23.72 23.72 23.72 23.72 23.72 23.72 23.72
23.72 (100.degree. C.) mm.sup.2/s 5.03 5.03 5.03 5.03 5.03 5.03
5.03 5.03 5.03 Base oil (mixture) viscosity index 144 144 144 144
144 144 144 144 144 Additive composition (based on total amount of
composition) Organic molybdenum compound F-1 % by mass 1.0 (1000)
0.5 (500) 0.5 (500) 0.5 (500) 0.5 (500) 0.5 (500) 0.5 (500) 0.5
(500) 0.5 (500) (amount in terms of the molybdenum element) mass
ppm Boron-containing dispersant G-1 % by mass 1.0 (200) 0.5 (100)
2.5 (500) 1.0 (200) 1.0 (200) 1.0 (200) 1.0 (200) 1.0 (200) 1.0
(200) (amount in terms of boron element) mass ppm Non-boron
dispersant H-1 % by mass -- -- -- -- -- -- -- -- -- Performance
additive C-1 % by mass 9.0 9.0 9.0 9.0 9.0 9.0 9.0 9.0 9.0
Viscosity modifier J-1 % by mass 3.5 3.5 3.5 2.5 7.0 10.0 15.0 5.0
-- Viscosity modifier J-2 % by mass -- -- -- -- -- -- -- 17.0 22.0
Viscosity modifier J-3 % by mass 4.7 4.7 4.7 5.3 3.0 1.0 -- -- --
Kinematic viscosity (40.degree. C.) mm.sup.2/s 40.0 39.9 41.0 39.8
39.4 38.7 39.9 40.8 40.8 High speed four-ball test 1800 rpm LNSL N
1236 981 1236 981 981 981 981 981 981 Wear scar diameter mm 0.94
0.97 0.85 0.90 0.95 0.96 0.94 0.92 0.91 Falex seizure test N 4359
4537 6672 4893 4493 4404 4359 5160 5382 IFW-1 test (friction
coefficient) (New oil) 90.degree. C. 0.091 0.087 0.093 0.090 0.096
0.095 0.093 0.094 0.095 (Degaded oil) 90.degree. C. 0.036 0.030
0.043 0.031 0.038 0.042 0.033 0.035 0.031 Oxidation stability
(ISOT) (Acid value increase) mgKOH/g 2.64 2.45 2.45 2.42 2.43 2.45
2.48 2.47 2.45
TABLE-US-00002 TABLE 2 Comparative Comparative Comparative
Comparative Example 1 Example 2 Example 3 Example 4 Base oil A-1 %
by mass 42 -- -- -- Base oil A-2 % by mass 58 -- 80 80 Base oil A-3
% by mass -- -- -- -- Base oil A-4 % by mass -- 20 -- -- Base oil
A-5 % by mass -- -- -- -- Base oil B-1 % by mass -- 80 20 20 Base
oil (mixture) kinematic viscosity (40.degree. C.) mm.sup.2/s 24.72
17.04 23.72 23.72 (100.degree. C.) mm.sup.2/s 5.03 4.13 5.03 5.03
Base oil (mixture) viscosity index 134 151 144 144 Additive
composition (based on total amount of composition) Organic
molybdenum compound F-1 % by mass 0.5 (500) 0.5 (500) -- 1.2 (1200)
(Amount in terms of the molybdenum element) mass ppm --
Boron-containing dispersant G-1 % by mass 1.0 (200) 1.0 (200) 1.0
(200) 1.0 (200) (Amount in terms of boron element) mass ppm
Non-boron dispersant H-1 % by mass -- -- -- -- Performance additive
C-1 % by mass 9.0 9.0 9.0 9.0 Viscosity modifier J-1 % by mass 3.5
3.5 3.5 3.5 Viscosity modifier J-2 % by mass -- -- -- -- Viscosity
modifier J-3 % by mass 4.7 4.7 4.7 4.7 Kinematic viscosity
(40.degree. C.) mm.sup.2/s 41.2 33.3 40.0 40.1 High speed four-ball
test 1800 rpm LNSL N 785 1236 981 1236 Wear scar diameter mm 1.23
0.95 1.11 0.96 Falex seizure test N 3870 8363 5338 4003 IFW-1 test
(friction coefficient) (New oil) 90.degree. C. 0.098 0.088 0.090
0.094 (Degraded oil) 90.degree. C. 0.095 0.036 0.091 0.048
Oxidation stability (ISOT) (Acid value mgKOH/g 2.1 3.11 2.23 2.83
increase)
[0125] As is apparent from Table 1 and Table 2, it was found that
the lubricating oil compositions of Examples 1 to 18 were better in
extreme pressure properties, wear resistance, seizure resistance,
abrasion resistance and oxidation stability, and had a smaller
metal-to-metal friction coefficient, than the lubricating oil
compositions of Comparative Examples 1 to 4.
* * * * *