U.S. patent application number 14/916353 was filed with the patent office on 2016-07-14 for lubricating oil composition for traction drive transmission.
This patent application is currently assigned to IDEMITSU KOSAN CO., LTD.. The applicant listed for this patent is IDEMITSU KOSAN CO., LTD.. Invention is credited to Hidetoshi KOGA.
Application Number | 20160201002 14/916353 |
Document ID | / |
Family ID | 52742963 |
Filed Date | 2016-07-14 |
United States Patent
Application |
20160201002 |
Kind Code |
A1 |
KOGA; Hidetoshi |
July 14, 2016 |
LUBRICATING OIL COMPOSITION FOR TRACTION DRIVE TRANSMISSION
Abstract
An object of the present invention is to provide a lubricating
oil composition capable of improving oxidation stability by
allowing a base number to remain, preserving seizure resistance,
preventing generation of precipitation to be caused due to addition
of a base, and inhibiting a lowering of traction coefficient. The
lubricating oil composition for traction drive transmission
includes (A) a base oil, (B) a phosphate ester-based compound, (C)
an antioxidant, and (D) an amine represented by the following
general formula (I) and/or an amine oxide of the amine.
##STR00001## In the general formula (I), each of R.sup.1 and
R.sup.2 independently represents a linear, branched, or cyclic
alkyl group having 1 to 26 carbon atoms, a linear, branched, or
cyclic alkenyl group having 1 to 26 carbon atoms,
(R.sup.4--O).sub.m--H, or
(R.sup.5--O).sub.n1--(R.sup.6--O).sub.n2--H, and R.sup.1 and
R.sup.2 may be the same as or different from each other; each of
R.sup.4 to R.sup.6 independently represents an alkylene group
having 2 to 3 carbon atoms; each of m, n1, and n2 independently
represents a number of 2 to 25; and R.sup.3 represents a
substituted or unsubstituted, linear, branched, or cyclic alkyl
group having 1 to 26 carbon atoms, or a substituted or
unsubstituted, linear, branched, or cyclic alkenyl group having 1
to 26 carbon atoms.
Inventors: |
KOGA; Hidetoshi;
(US) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IDEMITSU KOSAN CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
; IDEMITSU KOSAN CO., LTD.
Chiyoda-ku, Tokyo
JP
|
Family ID: |
52742963 |
Appl. No.: |
14/916353 |
Filed: |
September 5, 2014 |
PCT Filed: |
September 5, 2014 |
PCT NO: |
PCT/JP2014/073568 |
371 Date: |
March 3, 2016 |
Current U.S.
Class: |
508/439 |
Current CPC
Class: |
C10M 133/10 20130101;
C10M 2219/044 20130101; C10M 2215/064 20130101; C10N 2030/06
20130101; C10M 2207/2815 20130101; C10M 129/76 20130101; C10M
2215/065 20130101; C10N 2030/10 20130101; C10M 2203/045 20130101;
C10M 141/10 20130101; C10M 2223/04 20130101; C10N 2030/52 20200501;
C10M 2215/04 20130101; C10M 2207/262 20130101; C10M 2215/28
20130101; C10M 2207/289 20130101; C10M 2219/024 20130101; C10M
105/34 20130101; C10M 2215/223 20130101; C10M 137/04 20130101; C10M
169/04 20130101; C10M 2219/06 20130101; C10M 133/06 20130101; C10M
2207/026 20130101; C10M 105/04 20130101; C10M 2229/02 20130101;
C10N 2040/045 20200501; C10M 2215/08 20130101; C10M 133/12
20130101; C10M 2203/045 20130101; C10N 2060/02 20130101; C10M
2219/044 20130101; C10N 2010/04 20130101; C10M 2229/02 20130101;
C10N 2060/08 20130101; C10M 2207/262 20130101; C10N 2010/04
20130101; C10M 2219/044 20130101; C10N 2010/04 20130101; C10M
2207/262 20130101; C10N 2010/04 20130101; C10M 2229/02 20130101;
C10N 2060/08 20130101; C10M 2203/045 20130101; C10N 2060/02
20130101 |
International
Class: |
C10M 141/10 20060101
C10M141/10; C10M 105/04 20060101 C10M105/04; C10M 105/34 20060101
C10M105/34; C10M 133/10 20060101 C10M133/10; C10M 133/12 20060101
C10M133/12; C10M 129/76 20060101 C10M129/76; C10M 133/06 20060101
C10M133/06; C10M 169/04 20060101 C10M169/04; C10M 137/04 20060101
C10M137/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2013 |
JP |
2013-198825 |
Claims
1. A lubricating oil composition for traction drive transmission
preparing by blending (A) a base oil, (B) a phosphate ester-based
compound, (C) an antioxidant, and (D) an amine represented by the
following general formula (I) and/or an amine oxide of the amine:
##STR00007## wherein each of R.sup.1 and R.sup.2 independently
represents a linear, branched, or cyclic alkyl group having 1 to 26
carbon atoms, a linear, branched, or cyclic alkenyl group having 1
to 26 carbon atoms, (R.sup.4--O).sub.m--H, or
(R.sup.5--O).sub.n1--(R.sup.6--O).sub.n2--H, and R.sup.1 and
R.sup.2 may be the same as or different from each other; each of
R.sup.4 to R.sup.6 independently represents an alkylene group
having 2 to 3 carbon atoms; each of m, n1, and n2 independently
represents a number of 2 to 25; and R.sup.3 represents a
substituted or unsubstituted, linear, branched, or cyclic alkyl
group having 1 to 26 carbon atoms, or a substituted or
unsubstituted, linear, branched, or cyclic alkenyl group having 1
to 26 carbon atoms.
2. The lubricating oil composition for traction drive transmission
according to claim 1, wherein the base oil as the (A) component is
a naphthene-based synthetic oil.
3. The lubricating oil composition for traction drive transmission
according to claim 1, wherein in the amine represented by the
general formula (I), the sum total of carbon number of R.sup.1 to
R.sup.3 is 10 to 40.
4. The lubricating oil composition for traction drive transmission
according to claim 1, wherein in the amine represented by the
general formula (I), R.sup.1 and/or R.sup.2 is a methyl group, and
R.sup.3 is an unsubstituted alkyl group having 8 to 22 carbon
atoms.
5. The lubricating oil composition for traction drive transmission
according to claim 1, wherein the phosphate ester-based compound as
the (B) component and the amine represented by the general formula
(I) and/or the amine oxide of the amine as the (D) component are
blended in a mass ratio of 35/1 to 2/1.
6. The lubricating oil composition for traction drive transmission
according to claim 1, wherein 80 to 99% by mass of the base oil as
the (A) component, 0.05 to 10% by mass of the phosphate ester-based
ester compound as the (B) component, 0.1 to 1.6% by mass of the
antioxidant as the (C) component, and 0.05 to 4% by mass of the
amine represented by the general formula (I) and/or the amine oxide
of the amine as the (D) component are blended.
Description
TECHNICAL FIELD
[0001] The present invention relates to a lubricating oil
composition for traction drive transmission.
BACKGROUND ART
[0002] In recent years, with respect to transmissions for
automobile, such as a traction drive transmission (T-CVT), etc.,
not only there are trends toward capacity enlargement of
transmission power and miniaturization, but also there are
tendencies to demand fuel-saving properties and extension of no
change interval for fats and oils to be used therefor. In
consequence, lubricating oil compositions to be used for
transmissions for automobile are required to have oxidation
stability or extreme-pressure properties (seizure resistance) at
higher levels.
[0003] In relation to the foregoing issues, PTL 1 proposes a
lubricating oil composition containing an antioxidant composed of a
specified hindered phenol compound. In addition, PTL 2 proposes a
lubricating oil composition containing an acidic phosphate
ester.
CITATION LIST
Patent Literature
[0004] PTL 1: JP 6-293892 A
[0005] PTL 2: JP 2010-202680 A
SUMMARY OF INVENTION
Technical Problem
[0006] The lubricating oil composition of PTL 1 may exhibit a good
oxidation stability of the lubricating oil composition by the
hindered phenol compound; however, the seizure resistance is not
studied.
[0007] The lubricating oil composition of PTL 2 may exhibit a good
wear resistance of the lubricating oil composition by the acidic
phosphate ester; however, the seizure resistance and the oxidation
stability are not studied. In addition, in the case of adding the
acidic phosphate ester to the lubricating oil composition, for the
purpose of suppressing corrosion to be caused due to an increase of
acidity, it is required to take balance by adding a base to the
lubricating oil composition. However, in the case of adding a base
(monoamine compound) disclosed in PTL 2 to the lubricating oil
composition, there was a concern that the acidic phosphate ester
reacts with the instant amine to generate precipitation. In
addition, the lubricating oil composition of PTL 2 is used for
machine tools, but any lubricating oil composition for automobile
transmission is not described at all.
[0008] Furthermore, in order to appropriately transmit a power, the
lubricating oil compositions for traction drive transmission are
demanded to have a high traction coefficient. However, with respect
to the lubricating oil compositions of PTLs 1 and 2, a balance
between the traction coefficient and other performances is not
studied at all.
[0009] In the light of the above, any lubricating oil composition
for traction drive transmission capable of satisfying improvement
of oxidation stability, preservation of seizure resistance,
prevention of generation of precipitation to be caused due to
addition of a base, and inhibition of a lowering of traction
coefficient has not been proposed yet.
[0010] In view of the foregoing circumstances, the present
invention has been made, and an object thereof is to provide a
lubricating oil composition for traction drive transmission capable
of improving oxidation stability by allowing a base number to
remain, preserving seizure resistance, preventing generation of
precipitation to be caused due to addition of a base, and
inhibiting a lowering of traction coefficient.
Solution to Problem
[0011] In order to solve the aforementioned problem, the present
invention is to provide the following lubricating oil composition
for traction drive transmission. 1. A lubricating oil composition
for traction drive transmission preparing by blending (A) a base
oil, (B) a phosphate ester-based compound, (C) an antioxidant, and
(D) an amine represented by the following general formula (I)
and/or an amine oxide of the amine:
##STR00002##
[0012] wherein each of R.sup.1 and R.sup.2 independently represents
a linear, branched, or cyclic alkyl group having 1 to 26 carbon
atoms, a linear, branched, or cyclic alkenyl group having 1 to 26
carbon atoms, (R.sup.4--O).sub.n1--H, or
(R.sup.5--O).sub.n1--(R.sup.6--O).sub.n2--H, and R.sup.1 and
R.sup.2 may be the same as or different from each other; each of
R.sup.4 to R.sup.6 independently represents an alkylene group
having 2 to 3 carbon atoms; each of m, n1, and n2 independently
represents a number of 2 to 25; and
[0013] R.sup.3 represents a substituted or unsubstituted, linear,
branched, or cyclic alkyl group having 1 to 26 carbon atoms, or a
substituted or unsubstituted, linear, branched, or cyclic alkenyl
group having 1 to 26 carbon atoms.
Advantageous Effects of Invention
[0014] The lubricating oil composition for traction drive
transmission of the present invention is capable of preserving
seizure resistance while improving oxidation stability by allowing
a base number to remain, preventing generation of precipitation to
be caused due to addition of a base, and inhibiting a lowering of
traction coefficient.
DESCRIPTION OF EMBODIMENTS
[0015] The lubricating oil composition for traction drive
transmission of the present invention preparing by blending (A) a
base oil, (B) a phosphate ester-based compound, (C) an antioxidant,
and (D) an amine represented by the general formula (I) and/or an
amine oxide of the amine.
[0016] In the present invention, for example, the composition
prescribed as "the lubricating oil composition preparing by
blending (A) a base oil, (B) a phosphate ester-based compound, (C)
an antioxidant, and (D) an amine represented by the general formula
(I) and/or an amine oxide of the amine" includes not only a
"composition comprising the (A) to (D) components" but also a
"composition comprising, in place of at least one of the (A) to (D)
components, a modified material resulting from modification of the
at least one of the (A) to (D) components" and a "composition
comprising a reaction product resulting from reaction of at least a
part of the (A) to (D) components with each other".
[0017] It is to be noted that the "lubricating oil composition for
traction drive transmission of the present invention" will be
sometimes referred to as "lubricating oil composition".
[A Component: Base Oil]
[0018] As the base oil in the lubricating oil composition, a
mineral oil and/or a synthetic oil is used.
[0019] Examples of the mineral oil include paraffin-based mineral
oils, intermediate-based mineral oils, and naphthene-based mineral
oils, all of which are obtained by usual purification methods, such
as solvent purification, hydrogenation purification, etc., and the
like; and those prepared by isomerizing wax produced through
Fischer-Tropsch process (gas-to-liquid waxes) or mineral oil-based
wax; and the like.
[0020] Examples of the synthetic oil include hydrocarbon-based
synthetic oils, ether-based synthetic oils, and the like.
[0021] Examples of the hydrocarbon-based synthetic oil include
.alpha.-olefin oligomers or hydrides thereof, such as polybutene,
polyisobutylene, a 1-octene oligomer, a 1-decene oligomer, an
ethylene-propylene copolymer, etc.; aromatic compounds, such as an
alkylbenzene, an alkylnaphthalene, etc.; naphthene ring-containing
compounds, such as compounds having one naphthene ring, e.g.,
cyclopentane, cyclohexane, etc., compounds having two or more
naphthene rings, e.g., phychtelite, oleanane,
2,4-dicyclohexyl-2-methylpentane, bicyclo[2.2.1]heptane, a hydride
of a dimer of bicyclo[2.2.1]heptane ring compound,
octahydrometanonaphthalene, octahydrometanoindane,
decahydrometanoazulene, etc., etc.; and compounds resulting from
substitution of the aforementioned compounds having one naphthene
ring or compounds having two or more naphthene rings with one or
more alkyl groups or alkylene groups having 1 to 3 carbon atoms. It
is to be noted that with respect to crosslinked cyclic
hydrocarbons, in the case of bicyclic hydrocarbons, the number of
naphthene rings is defined as 2, and in the case of tricyclic
hydrocarbons, the number of naphthene rings is defined as 3.
[0022] Examples of the ether-based synthetic oil include
polyoxyalkylene glycols, polyphenyl ethers, and the like.
[0023] As for the base oil, only one of the aforementioned mineral
oils and/or the aforementioned synthetic oils may be used, or two
or more thereof may also be used. Furthermore, at least one mineral
oil and at least one synthetic oil may be used in combination.
[0024] Among the aforementioned base oils, naphthene-based mineral
oils or naphthene ring-containing compounds (naphthene-based
synthetic oils) are preferred from the viewpoint of increasing the
traction coefficient. Above all, naphthene-based synthetic oils are
more preferred, and especially, naphthene-based synthetic oils
having two or more naphthene rings are still more preferred.
[0025] Among the naphthene-based synthetic oils having two or more
naphthene rings, bicyclo[2.2.1]heptane and a hydride of a dimer or
trimer of bicyclo[2.2.1]heptane ring compound are suitable, with a
dimer being especially preferred.
[0026] Examples of the bicyclo[2.2.1]heptane ring compound include
compounds having a bicyclo[2.2.1]heptane ring, on which at least
one alkyl group having 1 to 3 carbon atoms may be substituted, and
having a molecular weight of 200 to 500. Examples of the dimer of
the instant compound include
endo-2-methyl-exo-3-methyl-exo-2-[(exo-3-methylbicyclo[2.2.1]hept-exo-2-y-
l)methyl]bicyclo[2.2.1]heptane,
endo-2-methyl-exo-3-methyl-exo-2-[(exo-2-methylbicyclo[2.2.1]hept-exo-3-y-
l)methyl]bicyclo[2.2.1]heptane,
endo-2-methyl-exo-3-methyl-exo-2-[(endo-3-methylbicyclo[2.2.1]hept-endo-2-
-yl)methyl]bicyclo[2.2.1]heptane,
endo-2-methyl-exo-3-methyl-exo-2-[(endo-2-methylbicyclo[2.2.1]hept-endo-3-
-yl)methyl]bicyclo[2.2.1]heptane, and the like. Examples of the
trimer of the instant compound include
3-methyl-2-[(3-methylbicyclo[2.2.1]hept-2-yl)methyl]-2-[(2,3-dimethylbicy-
clo[2.2.1]hept-2-yl)methyl]bicyclo[2.2.1]heptane,
2-[(bicyclo[2.2.1]hept-2-yl)methyl]-2-[(2-methylbicyclo[2.2.1]hept-2-yl)m-
ethyl]bicyclo[2.2.1]heptane,
2-[(bicyclo[2.2.1]hept-2-yl)ethyl]-2-[(2-ethylbicyclo[2.2.1]hept-2-yl)eth-
yl]bicyclo[2.2.1]heptane, and the like.
[0027] A blending amount of the base oil that is the (A) component
is preferably 80 to 99% by mass, and more preferably 90 to 95% by
mass relative to the total amount of the lubricating oil
composition from the viewpoint of keeping a high traction
coefficient while ensuring the blending proportions of other
components.
[B Component: Phosphate Ester-Based Compound]
[0028] In the present invention, a phosphate ester-based compound
is used as the B component. The phosphate ester-based compound has
a role of preserving the seizure resistance.
[0029] Examples of the phosphate ester-based compound include
phosphate esters, such as orthophosphate esters, acidic phosphate
esters, phosphite esters, etc. At least one of these phosphate
esters may be used. Among these phosphate esters, phosphite esters
are suitable, but they may be properly selected according to the
purpose.
[0030] As the orthophosphate ester, for example, those represented
by the following general formula (II) are useful.
##STR00003##
[0031] In the general formula (II), each of R.sup.7 to R.sup.9
represents an alkyl group having 4 to 24 carbon atoms, an alkenyl
group having 4 to 24 carbon atoms, or a hetero atom-containing
group having 4 to 24 carbon atoms which contains an atom selected
from an oxygen atom, a nitrogen atom, and a sulfur atom in the
aforementioned alkyl group or alkenyl group.
[0032] Though the alkyl group and the alkenyl group represented by
R.sup.7 to R.sup.9 may be linear, branched, or cyclic, they are
preferably linear. Furthermore, the alkyl group and the alkenyl
group represented by R.sup.7 to R.sup.9 have preferably 6 to 20
carbon atoms, and more preferably 7 carbon atoms.
[0033] In the case where R.sup.7 to R.sup.9 are each a hetero
atom-containing group, the number of hetero atoms is preferably 1
to 4, and the hetero atom is preferably a sulfur atom.
[0034] Examples of the alkyl group represented by R.sup.7 to
R.sup.9 include an octyl group, a nonyl group, a decyl group, an
undecyl group, a dodecyl group, a tridecyl group, a tetradecyl
group, a pentadecyl group, a hexadecyl group, a heptadecyl group,
an octadecyl group, a nonadecyl group, an eicosyl group, a
heneicosyl group, a docosyl group, a tricosyl group, and a
tetracosyl group. These may be linear, branched, or cyclic.
Examples of the alkenyl group include an octenyl group, a nonenyl
group, a decenyl group, an undecenyl group, a dodecenyl group, a
tridecenyl group, a tetradecenyl group, a pentadecenyl group, a
hexadecenyl group, a heptadecenyl group, an octadecenyl group, a
nonadecenyl group, an eicosenyl group, a heneicosenyl group, a
docosenyl group, a tricosenyl group, and a tetracosenyl group.
These may be linear, branched, or cyclic, and a position of the
double bond is arbitrary.
[0035] As the acidic phosphate ester, for example, those
represented by the following general formula (III) are useful.
##STR00004##
[0036] In the general formula (III), R.sup.10 represents a hydrogen
atom, an alkyl group having 4 to 24 carbon atoms, an alkenyl group
having 4 to 24 carbon atoms, or a hetero atom-containing group
having 4 to 24 carbon atoms which contains an atom selected from an
oxygen atom, a nitrogen atom, and a sulfur atom in the
aforementioned alkyl group or alkenyl group. Among those, an alkyl
group, an alkenyl group, or a hetero atom-containing group is
preferable. R.sup.11 represents an alkyl group having 4 to 24
carbon atoms, an alkenyl group having 4 to 24 carbon atoms, or a
hetero atom-containing group having 4 to 24 carbon atoms and
containing an atom selected from an oxygen atom, a nitrogen atom,
and a sulfur atom in the aforementioned alkyl group or alkenyl
group.
[0037] Though the alkyl group and the alkenyl group represented by
R.sup.10 and R.sup.11 may be linear, branched, or cyclic, they are
preferably linear. Furthermore, the alkyl group and the alkenyl
group represented by R.sup.10 and R.sup.11 have preferably 6 to 20
carbon atoms.
[0038] Specific examples of the alkyl group and the alkenyl group
represented by R.sup.10 and R.sup.11 are the same as those in
R.sup.7 to R.sup.9.
[0039] With respect to the hetero atom-containing group as R.sup.10
or R.sup.11, the number of hetero atoms is preferably 1 to 4, and
the hetero atom is preferably a sulfur atom.
[0040] As the phosphite ester, for example, those represented by
the following general formula (IV) are useful.
##STR00005##
[0041] In the general formula (Iv), R.sup.12 represents a hydrogen
atom, an alkyl group having 4 to 24 carbon atoms, an alkenyl group
having 4 to 24 carbon atoms, or a hetero atom-containing group
having 4 to 24 carbon atoms and containing an atom selected from an
oxygen atom, a nitrogen atom, and a sulfur atom in the
aforementioned alkyl group or alkenyl group. Among those, an alkyl
group, an alkenyl group, or a hetero atom-containing group is
preferable. R.sup.13 represents an alkyl group having 4 to 24
carbon atoms, an alkenyl group having 4 to 24 carbon atoms, or a
hetero atom-containing group having 4 to 24 carbon atoms and
containing an atom selected from an oxygen atom, a nitrogen atom,
and a sulfur atom in the aforementioned alkyl group or alkenyl
group.
[0042] Though the alkyl group and the alkenyl group represented by
R.sup.12 and R.sup.13 may be linear, branched, or cyclic, they are
preferably linear. Furthermore, the alkyl group and the alkenyl
group represented by R.sup.12 and R.sup.13 have preferably 6 to 20
carbon atoms, and more preferably 6 to 12 carbon atoms.
[0043] With respect to the hetero atom-containing group as R.sup.12
or R.sup.13, the number of hetero atoms is preferably 1 to 4, and
the hetero atom is preferably a sulfur atom.
[0044] Specific examples of the alkyl group and the alkenyl group
represented by R.sup.12 and R.sup.13 are the same as those in
R.sup.7 to R.sup.9.
[0045] A blending amount of the phosphate ester-based compound as
the B component is preferably 0.05 to 10% by mass, and more
preferably 0.5 to 8% by mass relative to the total amount of the
lubricating oil composition from the viewpoints of improving the
seizure resistance and inhibiting a lowering of the traction
coefficient.
[C Component: Antioxidant]
[0046] In the present invention, an antioxidant is used as the C
component. Examples of the antioxidant include amine-based
antioxidants, phenol-based antioxidants, and sulfur-based
antioxidants.
[0047] Examples of the amine-based antioxidant include
dialkyldiphenylamines (the carbon number of the alkyl group is 1 to
20), such as 4,4'-dibutyldiphenylamine, 4,4'-dioctyldiphenylamine,
4,4'-dinonyldiphenylamine, etc.; and naphthylamines, such as
phenyl-.alpha.-naphthylamine, octylphenyl-.alpha.-naphthylamine,
nonylphenyl-.alpha.-naphthylamine, etc.
[0048] Examples of the phenol-based antioxidant include
monophenol-based antioxidants, such as
2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol,
etc.; and diphenol-based antioxidants, such as
4,4'-methylenebis(2,6-di-tert-butylphenol),
2,2'-methylenebis(4-ethyl-6-tert-butylphenol), etc.
[0049] Examples of the sulfur-based antioxidant include
phenothiazine, pentaerythritol-tetrakis-(3-laurylthiopropionate),
bis(3-tert-butyl-4-hydroxybenzyl)sulfide, thiodiethylenebis
(3-(3,5-di-tert-butyl-4-hydroxyphenyl))propionate,
2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine-2-methylamino)phen-
ol, and the like.
[0050] The aforementioned antioxidants may be used alone, or may be
used in combination of two or more thereof. In the present
invention, a combination of the phenol-based antioxidant with the
amine-based antioxidant or sulfur-based antioxidant is preferably
used, and a combination of the phenol-based antioxidant with the
amine-based antioxidant is optimum.
[0051] A blending amount of the antioxidant as the C component is
preferably 0.1 to 1.6% by mass, and more preferably 0.5 to 1% by
mass relative to the total amount of the lubricating oil
composition from the viewpoints of improving the oxidation
stability and inhibiting a lowering of the traction
coefficient.
[D Component: Amine]
[0052] In the present invention, an amine represented by the
general formula (I) and/or an amine oxide of the instant amine
(hereinafter sometimes referred to as "amine of the D component")
is used as the D component. Either of the amine represented by the
general formula (I) and the amine oxide of the instant amine may
bring the effects of the present invention, but the amine
represented by the general formula (I) is preferable from the
viewpoints that it is likely to allow the base number to remain and
that it is excellent in maintenance of the oxidation stability.
##STR00006##
[0053] In the general formula (I),
[0054] each of R.sup.1 and R.sup.2 independently represents a
linear, branched, or cyclic alkyl group having 1 to 26 carbon
atoms, a linear, branched, or cyclic alkenyl group having 1 to 26
carbon atoms, (R.sup.4--O).sub.m--H, or
(R.sup.5--O).sub.n1--(R.sup.6--O).sub.n2--H, and R.sup.1 and
R.sup.2 may be the same as or different from each other; each of
R.sup.4 to R.sup.6 independently represents an alkylene group
having 2 to 3 carbon atoms; each of m, n1, and n2 independently
represents a number of 2 to 25; and
[0055] R.sup.3 represents a substituted or unsubstituted, linear,
branched, or cyclic alkyl group having 1 to 26 carbon atoms, or a
substituted or unsubstituted, linear, branched, or cyclic alkenyl
group having 1 to 26 carbon atoms.
[0056] The amine as the D component plays a role of not only
neutralizing the acidity which has been increased by the addition
of the phosphate ester-based compound as the B component, to
inhibit corrosion of the metal but also inhibiting oxidation of the
lubricating oil composition, to improve the oxidation stability. As
other basic substances, a metal-based detergent, a primary amine,
and a second amine might be thought. However, the metal-based
detergent is excessively high in reactivity, so that the effect for
preserving the seizure resistance of the phosphate ester-based
compound as the B component is impaired. With respect to the
primary amine and the secondary amine, there is a concern that such
an amine reacts with the phosphate ester-based compound to generate
precipitation.
[0057] In the general formula (I), each of R.sup.1 to R.sup.3 is
preferably an alkyl group, and more preferably an unsubstituted
linear alkyl group from the viewpoint of improving the
stability.
[0058] In the general formula (I), the sum total of carbon number
of R.sup.1 to R.sup.3 is preferably 10 to 40, more preferably 11 to
23, and still more preferably 12 to 22. When the sum total of
carbon number is 10 or more, the amine as the D component may be
allowed to remain as an effective component for a long period of
time, and when the sum total of carbon number is 40 or less, the
addition amount of the amine as the D component may be suppressed
while ensuring the basic effective component in a certain
proportion.
[0059] In the general formula (I), it is preferred that one or two
of R.sup.1 and R.sup.2 are a methyl group, and it is more preferred
that both of R.sup.1 and R.sup.2 are a methyl group. From the
viewpoint of improving the stability, R.sup.3 is preferably an
unsubstituted linear alkyl group having 8 to 22 carbon atoms, and
more preferably an unsubstituted linear alkyl group having 10 to 20
carbon atoms.
[0060] The amine as the D component may be used alone, or may be
used in admixture of two or more thereof.
[0061] With respect to the amine as the D component, from the
viewpoint of inhibiting a lowering of the traction coefficient, its
base number is preferably one at which the blending amount of the D
component becomes small, and the base number is preferably 50
mgKOH/g or more, and more preferably 100 mgKOH/g or more. It is to
be noted that the base number as referred to in the present
invention refers to a value measured by the hydrochloric acid
method in conformity with JIS K2501.
[0062] A blending amount of the amine as the D component is
preferably 0.05 to 4% by mass, more preferably 0.1 to 0.8% by mass,
and still more preferably 0.15 to 0.5% by mass relative to the
total amount of the lubricating oil composition from the viewpoints
of appropriate neutralization and inhibition of a lowering of the
traction coefficient.
[0063] In the lubricating oil composition, the phosphate
ester-based compound as the B component and the amine as the D
component are preferably blended in a mass ratio of 35/1 to 2/1,
and more preferably blended in a mass ratio of 20/1 to 3/1. By
blending these components in such a mass ratio, it is possible to
improve a balance between the seizure resistance and the inhibition
of corrosion favorable.
[E Component: Lubricating Oil Additive]
[0064] In the lubricating oil composition of the present invention,
a lubricating oil additive may be further blended as an E component
in the composition of the A to D components.
[0065] Examples of the lubricating oil additive as the E component
include a viscosity index improver, a friction modifier, other
lubricating oil additives, and the like. It is preferred to blend
one or two or more lubricating oil additives selected from the
foregoing additives.
[0066] Examples of the friction modifier include partial ester
compounds obtained through reaction between a fatty acid and an
aliphatic polyhydric alcohol. In the partial ester compound, the
fatty acid is preferably a fatty acid having a linear or branched
hydrocarbon group having 6 to 30 carbon atoms, and the carbon
number of the hydrocarbon group is more preferably 8 to 24, and
especially preferably 10 to 20. Examples of the fatty acid include
saturated fatty acids, such as caproic acid, caprylic acid, capric
acid, lauric acid, myristic acid, palmitic acid, stearic acid,
arachidic acid, behenic acid, lignoceric acid, etc.; and
unsaturated fatty acids, such as myristoleic acid, palmitoleic
acid, oleic acid, linoleic acid, etc., with oleic acid being
preferred. The aforementioned aliphatic polyhydric alcohol is an
alcohol having a valence of 2 to 6, and examples thereof include
ethylene glycol, glycerin, trimethylolpropane, pentaerythritol,
sorbitol, sorbitan, and the like, with sorbitan being preferred.
These partial ester compounds may be used alone, or may be used in
combination of two thereof.
[0067] A fatty acid saturated monoamine and an unsaturated
monoamine each having about 10 to 20 carbon atoms, such as
stearylamine, oleylamine, etc., may also be suitably used as the
friction modifier.
[0068] Examples of other lubricating oil additives include an
antifoaming agent, a metal deactivator, an ultraviolet absorber, a
rust-preventive agent, a pour-point depressant, and the like.
Examples of the antifoaming agent include a silicone oil, a
fluorinated silicone oil, and the like, and examples of the metal
deactivator include copper deactivators, such as an
N--[N,N'-dialkylaminomethyl] triazole (the carbon number of the
alkyl group is 3 to 12), etc., and the like.
[0069] A blending amount of the lubricating oil additive varies
with a performance to be added, and hence, it may not be
unequivocally defined. However, it is preferably 3% by mass or
less, and more preferably 0.1 to 1% by mass relative to the total
amount of the lubricating oil composition.
[0070] It is preferred that the lubricating oil composition does
not substantially contain a primary or secondary aliphatic amine.
What the lubricating oil composition does not substantially contain
a primary or secondary aliphatic amine means that the amount of the
primary or secondary aliphatic amine is 0.1% by mass or less,
preferably 0.01% by mass or less, and more preferably 0% by mass on
the basis of the total amount of the lubricating oil composition.
It is to be noted that even a primary or secondary amine may be
added within the range where the effects of the present invention
are not impaired. For example, so long as a primary or secondary
amine having more than 20 carbon atoms is concerned, it tends to
hardly generate a precipitate while it depends on a kind of the
base oil.
[Traction Drive Transmission]
[0071] The traction drive transmission of the present invention is
one using the aforementioned lubricating oil composition for
traction drive transmission of the present invention as a
lubricating oil composition contained in a traction drive
transmission.
[0072] As a main body of the traction drive transmission, those
which are conventionally known may be used. As the lubricating oil
composition contained in the traction drive transmission, the
aforementioned lubricating oil composition for traction drive
transmission of the present invention is used.
[0073] The traction drive transmission of the present invention is
excellent in remaining properties of the base number, and hence, it
has thorough oxidation stability, preserves seizure resistance, and
is free from an obstruction by a precipitate, high in a traction
coefficient, and excellent in power transmission.
EXAMPLES
[0074] Next, the present invention is hereunder described in more
detail by reference to Examples, but it should be construed that
the present invention is in no way limited by these Examples. It is
to be noted that in the Examples, the lubricating oil compositions
were evaluated and measured in the following manners. The results
are shown in Tables 1 and 2.
<Evaluation Method and Measurement Method of Lubricating Oil
Composition>
(1) Base Number
[0075] A base number of a lubricating oil composition (new oil) was
measured the hydrochloric acid method in conformity with JIS
K2501.
(2) Seizure Resistance
[0076] In the Falex test (rotation rate: 290 rpm, oil temperature:
100.degree. C.) in conformity with ASTM D3233 (A method), a load
(N) at which a test piece caused seizure was measured. It is meant
that the larger the load, the more excellent the seizure resistance
performance is. A test piece which did not cause the seizure even
at a load of 13,340 N is designated as ">13340".
(3) Remaining Base Number Amount
[0077] A base number of a lubricating oil composition which had
been subjected to an oxidation stability test under conditions at
150.degree. C. for 240 hours in conformity with CEC L-48-A-00[B]
was measured by the hydrochloric acid method in conformity with JIS
K2501.
(4) Appearance
[0078] An appearance of a lubricating oil composition (new oil)
immediately after blending was observed through visual inspection.
The case where any change of the appearance was not observed is
designated as "A", the case where the appearance was cloudy is
designated as "B", and the case where precipitation was generated
is designated as "C".
(5) Traction Coefficient
[0079] The measurement of the traction coefficient at 100.degree.
C. was performed by using a two-cylinder friction tester. That is,
the traction coefficient was determined with two cylinders each
having the same size and coming into contact with each other (which
had a diameter of 40 mm and a thickness of 20 mm and which were
composed of a drum-shaped driven cylinder with a curvature radius
of 20 mm and a flat driving cylinder without crowning) by rotating
either one of the cylinders at a constant velocity while
continuously varying a rotational velocity of the other, applying a
load of 147.1 N to the contact portion of the both cylinders by a
weight, and measuring a tangent force generating between the both
cylinders, that is, the objective traction force. The cylinders
were made of chromium molybdenum steel SCM420 and mirror-finished,
an average circumferential velocity was 6.8 m/s, and a maximum
hertz contact pressure was 1.24 GPa. The traction coefficient was
measured under conditions at a slip ratio of 5%.
(6) .mu. Decrease Rate
[0080] A decrease ratio of the traction coefficient of each of the
Examples and Comparative Examples relative to the traction
coefficient of Comparative Example 1 was calculated based on the
traction coefficients thus obtained above.
Examples 1 to 18 and Comparative Examples 1 to 15
[0081] Materials shown in Tables 1 and 2 were blended and stirred
at 80.degree. C. for 30 minutes to prepare lubricating oil
compositions, followed by undergoing the aforementioned evaluations
and measurements.
[0082] It is to be noted that the symbols of the raw materials used
in Tables 1 and 2 express as follows.
(A Component)
[0083] A-1: Naphthene-based synthetic oil (hydride of dimer of
bicyclo[2.2.1]heptane ring compound) (mixture of
endo-2-methyl-exo-3-methyl-exo-2-[(exo-3-methylbicyclo[2.2.1]hept-exo-2-y-
l)methyl]bicyclo[2.2.1]heptane and
endo-2-methyl-exo-3-methyl-exo-2-[(exo-2-methylbicyclo[2.2.1]hept-exo-3-y-
l)methyl]bicyclo[2.2.1]heptane) (number of naphthene rings: 4) A-2:
Naphthene-based synthetic oil (2,4-clicyclohexyl-2-methylpentane)
(number of naphthene rings: 2) A-3: Naphthene-based synthetic oil
((1S,3aR,4S,8aS)-4,8,8-trimethyl-9-methylene-decahydro-1,4-metanoazulene)
A-4: Ester-based synthetic oil (3,5,5-trimethylhexanoic acid
3,5,5-trimethylhexyl ester)
(B Component)
[0084] Phosphate ester-based compound (phosphorus content: 920 ppm,
total acid number: 1.95 mgKOH/g)
(C Component)
[0085] C-1: Monobutylphenyl monooctylphenylamine C-2:
Pentaerythritol
tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] C-3:
Benzenepropanoic acid,
3,5-bis(1,1-dimethyl-ethyl)-4-hydroxy-C7-C9-alkyl ester (side
chain) C-4: 2,6-Di-tert-butyl-4-methylphenol C-5:
Phenyl-1-naphthylamine C-6: Bis(tridecyl) thiodipropionate
(D Component)
[0086] D-1: N-Methyldioleylamine (total carbon number of R.sup.1 to
R.sup.3 in the general formula (I): 37, base number: 107 mgKOH/g)
D-2: N-Methyldidecylamine (total carbon number of R.sup.1 to
R.sup.3 in the general formula (I): 21, base number: 184 mgKOH/g)
D-3: Dimethyldodecylamine (total carbon number of R.sup.1 to
R.sup.3 in the general formula (I): 14, base number: 261 mgKOH/g)
D-4: Trioctylamine (total carbon number of R.sup.1 to R.sup.3 in
the general formula (I): 24, base number: 154 mgKOH/g) D-5:
Dicyclohexylmethylamine (total carbon number of R.sup.1 to R.sup.3
in the general formula (I): 13, base number: 297 mgKOH/g) D-6:
N,N-Dimethyloctylamine (total carbon number of R.sup.1 to R.sup.3
in the general formula (I): 10, base number: 327 mgKOH/g)
(E Component)
[0087] E-1: Detergent dispersant (calcium long chain alkyl
sulfonate) E-2: Detergent dispersant (polyolefin polyamine
succinimide.polyol) E-3: Detergent dispersant (calcium long chain
alkyl salicylate) E-4: Friction modifier (mixture of long chain
alkyl polyamide, thio alkyl long chain alkyl ester, and oleic acid
monoglyceride (mixture ratio:8/2/1)) E-5: Antifoaming agent
(fluorinated silicone) E-6: Benzotriazole-based ultraviolet
absorber (aliphatic primary amine or secondary amine) F-1:
Oleylamine (aliphatic primary amine) F-2: Di-hardened tallow
alkylamine (carbon number of individual alkyl group: 12 to 20, C16:
30%, C18: 64%) (aliphatic secondary amine)
TABLE-US-00001 TABLE 1 Example Raw material 1 2 3 4 5 6 7 8 9 A-1
63.00 62.55 62.05 61.56 63.05 62.35 63.23 63.03 62.68 A-2 -- -- --
-- -- -- -- -- -- A-3 28.50 28.50 28.50 28.50 28.50 28.50 28.50
28.50 28.50 A-4 -- -- -- -- -- -- -- -- -- B 6.65 6.65 6.65 6.65
6.65 6.65 6.65 6.65 6.65 C-1 0.40 0.40 0.40 0.40 0.40 0.40 0.40
0.40 0.40 C-2 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 C-3 --
-- -- -- -- -- -- -- -- C-4 -- -- -- -- -- -- -- -- -- C-5 -- -- --
-- -- -- -- -- -- C-6 -- -- -- -- -- -- -- -- -- D-1 0.45 0.90 1.40
1.89 -- -- -- -- -- D-2 -- -- -- -- 0.40 1.10 -- -- -- D-3 -- -- --
-- -- -- 0.20 0.40 0.77 D-4 -- -- -- -- -- -- -- -- -- D-5 -- -- --
-- -- -- -- -- -- D-6 -- -- -- -- -- -- -- -- -- E-1 -- -- -- -- --
-- -- -- -- E-2 -- -- -- -- -- -- -- -- -- E-3 -- -- -- -- -- -- --
-- -- E-4 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.55 E-5 0.02
0.02 0.02 0.02 0.02 0.02 0.04 0.04 0.02 E-6 0.03 0.03 0.03 0.03
0.03 0.03 0.03 0.03 0.03 F-1 -- -- -- -- -- -- -- -- -- F-2 -- --
-- -- -- -- -- -- -- Total 100.00 100.00 100.00 100.00 100.00
100.00 100.00 100.00 100.00 Base number 1.73 2.20 2.74 3.22 1.93
3.17 1.63 2.2 3.18 (mgKOH/g) Seizure resistance >13340 >13340
>13340 >13340 >13340 >13340 >13340 >13340
>13340 (N) Remaining base 0.24 0.39 0.48 0.69 0.47 1.12 0.53
0.52 1.07 number Appearance A A A A A A A A A Traction coefficient
0.0845 0.0844 0.0831 0.0829 0.0842 0.0833 0.0847 0.0845 0.0845 .mu.
Decrease ratio 0.6 0.7 2.2 2.5 0.9 2.0 0.4 0.6 0.6 (%) Example Raw
material 10 11 12 13 14 15 16 17 18 A-1 61.95 60.45 62.15 62.78
62.99 91.25 41.25 -- -- A-2 -- -- -- -- -- -- -- 91.25 -- A-3 28.50
28.50 28.50 28.50 28.50 0.50 50.50 0.50 0.50 A-4 -- -- -- -- -- --
-- -- 91.25 B 6.65 6.65 6.65 6.65 6.65 6.65 6.65 6.65 6.65 C-1 0.40
0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 C-2 0.40 0.40 0.40 0.40
0.40 0.40 0.40 0.40 0.40 C-3 -- -- -- -- -- -- -- -- -- C-4 -- --
-- -- -- -- -- -- -- C-5 -- -- -- -- -- -- -- -- -- C-6 -- -- -- --
-- -- -- -- -- D-1 -- -- -- -- -- -- -- -- -- D-2 -- -- -- -- -- --
-- -- -- D-3 1.50 3.00 -- -- -- 0.20 0.20 0.20 0.20 D-4 -- -- 1.30
-- -- -- -- -- -- D-5 -- -- -- 0.67 -- -- -- -- -- D-6 -- -- -- --
0.46 -- -- -- -- E-1 -- -- -- -- -- -- -- -- -- E-2 -- -- -- -- --
-- -- -- -- E-3 -- -- -- -- -- -- -- -- -- E-4 0.55 0.55 0.55 0.55
0.55 0.55 0.55 0.55 0.55 E-5 0.02 0.02 0.02 0.02 0.02 0.02 0.02
0.02 0.02 E-6 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 F-1 --
-- -- -- -- -- -- -- -- F-2 -- -- -- -- -- -- -- -- -- Total 100.00
100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 Base number
5.76 9.7 3.27 3.13 3.28 1.75 1.75 1.74 1.77 (mgKOH/g) Seizure
resistance >13340 >13340 >13340 >13340 >13340
>13340 >13340 >13340 >13340 (N) Remaining base 1.99
3.75 0.35 0.53 0.07 0.38 0.34 0.41 0.12 number Appearance A A A B A
A A A A Traction coefficient 0.0833 0.0813 0.0836 0.0842 0.0844
0.0847 0.0800 0.0847 0.0740 .mu. Decrease ratio 2.0 4.4 1.6 0.9 0.7
0.4 5.9 0.4 12.9 (%)
TABLE-US-00002 TABLE 2 Comparative Example Raw material 1 2 3 4 5 6
7 8 A-1 63.45 62.65 61.85 62.39 61.46 62.25 62.10 61.74 A-2 -- --
-- -- -- -- -- -- A-3 28.50 28.50 28.50 28.50 28.50 28.50 28.50
28.50 A-4 -- -- -- -- -- -- -- -- B 6.65 6.65 6.65 6.65 6.65 6.65
6.65 6.65 C-1 0.40 0.80 1.20 0.80 1.20 1.00 0.40 0.40 C-2 0.40 0.80
1.20 -- -- -- 0.40 0.40 C-3 -- -- -- 1.06 1.59 -- -- -- C-4 -- --
-- -- -- 0.30 -- -- C-5 -- -- -- -- -- 0.20 -- -- C-6 -- -- -- --
-- 0.50 -- -- D-1 -- -- -- -- -- -- -- -- D-2 -- -- -- -- -- -- --
-- D-3 -- -- -- -- -- -- -- -- D-4 -- -- -- -- -- -- -- -- D-5 --
-- -- -- -- -- -- -- D-6 -- -- -- -- -- -- -- -- E-1 -- -- -- -- --
-- -- -- E-2 -- -- -- -- -- -- -- -- E-3 -- -- -- -- -- -- -- --
E-4 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.55 E-5 0.02 0.02 0.02 0.02
0.02 0.02 0.02 0.02 E-6 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 F-1
-- -- -- -- -- -- 1.35 -- F-2 -- -- -- -- -- -- -- 1.71 Total
100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 Base number
1.17 1.29 1.26 1.25 1.26 1.26 4.49 3.13 (mgKOH/g) Seizure
resistance >13340 >13340 >13340 >13340 >13340
>13340 >13340 >13340 (N) Remaining base 0.00 0.00 0.00
0.00 0.00 0.00 0.03 0.20 number Appearance A A A A A A C C Traction
coefficient 0.0850 0.0841 0.0830 0.0838 0.0826 0.0836 0.834 0.0830
.mu. Decrease ratio -- 1.1 2.4 1.4 2.8 1.6 1.9 2.4 (%) Comparative
Example Raw material 9 10 11 12 13 14 15 A-1 62.83 62.67 62.56
91.45 41.45 -- -- A-2 -- -- -- -- -- 91.45 -- A-3 28.50 28.50 28.50
0.50 50.50 0.50 0.50 A-4 -- -- -- -- -- -- 91.45 B 6.65 6.65 6.65
6.65 6.65 6.65 6.65 C-1 0.40 0.40 0.40 0.40 0.40 0.40 0.40 C-2 0.40
0.40 0.40 0.40 0.40 0.40 0.40 C-3 -- -- -- -- -- -- -- C-4 -- -- --
-- -- -- -- C-5 -- -- -- -- -- -- -- C-6 -- -- -- -- -- -- -- D-1
-- -- -- -- -- -- -- D-2 -- -- -- -- -- -- -- D-3 -- -- -- -- -- --
-- D-4 -- -- -- -- -- -- -- D-5 -- -- -- -- -- -- -- D-6 -- -- --
-- -- -- -- E-1 0.62 -- -- -- -- -- -- E-2 -- 0.78 -- -- -- -- --
E-3 -- -- 0.89 -- -- -- -- E-4 0.55 0.55 0.55 0.55 0.55 0.55 0.55
E-5 0.02 0.02 0.02 0.02 0.02 0.02 0.02 E-6 0.03 0.03 0.03 0.03 0.03
0.03 0.03 F-1 -- -- -- -- -- -- -- F-2 -- -- -- -- -- -- -- Total
100.00 100.00 100.00 100.00 100.00 100.00 100.00 Base number 1.04
1.22 1.31 1.25 1.22 1.22 1.25 (mgKOH/g) Seizure resistance 4220
3420 2280 >13340 >13340 >13340 >13340 (N) Remaining
base 0.03 0.02 0.08 0.02 0.01 0.03 0.00 number Appearance A A A A A
A A Traction coefficient 0.0843 0.0841 0.0840 0.0849 0.0800 0.0849
0.0740 .mu. Decrease ratio 0.8 1.1 1.2 0.1 5.9 0.1 12.9 (%)
[0088] The following are understood from Tables 1 and 2. The
lubricating oil compositions of the Examples could allow the base
number to thoroughly remain even after the long-term use under
high-temperature circumstances. This matter means that the base
always exists even in the use under severe conditions, and the
oxidation stability is favorable. In addition, the lubricating oil
compositions of the Examples could preserve the seizure resistance
without causing seizure even at a load of 13,340 N and did not
generate precipitation by the addition of the base. In addition,
the lubricating oil compositions of the Examples were less in a
lowering of the traction coefficient relative to Comparative
Example 1 as a reference and could inhibit a lowering of the
traction coefficient.
[0089] In contrast, the lubricating oil compositions of Comparative
Examples 1 to 7, 9 to 10, and 12 to 15 could not allow the base
number to thoroughly remain after the long-term use under
high-temperature circumstances. This matter means that the amount
of the base is not sufficient in the use under severe conditions,
and the oxidation stability is not satisfactory. In addition, in
Comparative Examples 7 and 8, in view of the fact that the primary
amine or secondary amine was used, the precipitation was generated.
In addition, in Comparative Examples 9 to 11, in view of the fact
that the metal-based detergent dispersant was used, the effect for
preserving the seizure resistance of the phosphate ester-based
compound as the B component was impaired.
INDUSTRIAL APPLICABILITY
[0090] According to the present invention, it is possible to
provide a lubricating oil composition capable of improving
oxidation stability by allowing a base number to remain, preserving
seizure resistance, preventing generation of precipitation to be
caused due to addition of a base, and inhibiting a lowering of
traction coefficient. In consequence, the lubricating oil
composition of the present invention is able to be effectively
utilized as a lubricating oil composition for traction drive
transmission (T-CVT).
* * * * *