U.S. patent application number 10/816274 was filed with the patent office on 2004-09-30 for lubricating oil composition.
This patent application is currently assigned to Nippon Oil Corporation. Invention is credited to Morita, Eitaro.
Application Number | 20040192562 10/816274 |
Document ID | / |
Family ID | 19126522 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040192562 |
Kind Code |
A1 |
Morita, Eitaro |
September 30, 2004 |
Lubricating oil composition
Abstract
A lubricating oil composition which comprises (A) a base oil,
(B) calcium salicylate having a base number of 50 to 300 mgKOH/g in
an amount of 0.005 to 0.07 percent by mass in terms of calcium, (C)
an SP type extreme pressure additive in an amount of 0.005 to 0.07
percent by mass in terms of phosphorous, (D) a specific succinimide
compound in an amount of 0.1 to 6 percent by mass, and (E) a
boron-containing ashless dispersant in an amount of 0.001 to 0.05
percent by mass in terms of boron, based on the total mass of the
composition. The lubricating oil composition can prevent pitching
of a transmission, resulting in the extended fatigue life thereof,
and exhibits excellent and long-lasting anti-shudder
properties.
Inventors: |
Morita, Eitaro;
(Yokohama-shi, JP) |
Correspondence
Address: |
AKIN GUMP STRAUSS HAUER & FELD L.L.P.
ONE COMMERCE SQUARE
2005 MARKET STREET, SUITE 2200
PHILADELPHIA
PA
19103-7013
US
|
Assignee: |
Nippon Oil Corporation
|
Family ID: |
19126522 |
Appl. No.: |
10/816274 |
Filed: |
April 1, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10816274 |
Apr 1, 2004 |
|
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PCT/JP02/10279 |
Oct 2, 2002 |
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Current U.S.
Class: |
508/185 ;
508/291; 508/433; 508/441; 508/460 |
Current CPC
Class: |
C10M 2223/045 20130101;
C10M 2223/065 20130101; C10M 2215/08 20130101; C10M 2207/144
20130101; C10N 2040/042 20200501; C10N 2040/045 20200501; C10N
2030/06 20130101; C10N 2060/14 20130101; C10M 2207/262 20130101;
C10M 2223/047 20130101; C10M 2223/049 20130101; C10M 2215/28
20130101; C10M 163/00 20130101; C10M 2215/086 20130101; C10M
2215/28 20130101; C10M 2215/28 20130101 |
Class at
Publication: |
508/185 ;
508/291; 508/433; 508/441; 508/460 |
International
Class: |
C10M 163/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 2, 2001 |
JP |
2001-306979 |
Claims
1. A lubricating oil composition which comprises (A) a base oil,
(B) calcium salicylate having a base number of 50 to 300 mgKOH/g in
an amount of 0.005 to 0.07 percent by mass in terms of calcium, (C)
an SP type extreme pressure additive in an amount of 0.005 to 0.07
percent by mass in terms of phosphorous, (D) one or more compounds
selected from the group consisting of succinimide compounds
represented by formulas (3) and (4) below in an amount of 0.1 to 6
percent by mass, and (E) a boron-containing ashless dispersant in
an amount of 0.001 to 0. 05 percent by mass in terms of boron,
based on the total mass of the composition: 9wherein R.sup.11 is a
straight-chain or branched hydrocarbon group having 8 to 30 carbon
atoms, R.sup.12 is hydrogen or a hydrocarbon group having 1 to 30
carbon atoms, R.sup.13 is a hydrocarbon group having 1 to 4 carbon
atoms, and m is an integer of from 1 to 7; 10wherein R.sup.14 and
R.sup.15 are each independently a straight-chain or branched
hydrocarbon group having 8 to 30 carbon atoms, and R.sup.16 and
R.sup.17 are each independently a hydrocarbon group having 1 to 4
carbon atoms, and n is an integer of from 1 to 7.
2. The lubricating oil composition according to claim 1 wherein (C)
SP type extreme pressure additive is at least one compound selected
from the group consisting of phosphorus compounds represented by
formulas (1) and (2) and salts thereof: 11wherein at least one of
X.sup.1, X.sup.2, and X.sup.3 is sulfur and the remainder is
oxygen, and R.sup.1, R.sup.2, and R.sup.3 are each independently
hydrogen or a hydrocarbon group having 1 to 30 carbon atoms; and
12wherein X.sup.4, X.sup.5, and X.sup.6 are each independently
oxygen or sulfur, and R.sup.4, R.sup.5, and R.sup.6 are each
independently hydrogen or a hydrocarbon having 1 to 30 carbon
atoms.
3. The lubricating oil composition according to claim 1 wherein (A)
lubricating base oil comprises (A-1) a mineral and/or synthetic oil
having a kinematic viscosity at 100.degree. C. of 2 to 6 mm.sup.2/s
in an amount of 60 to 99.5 percent by mass and (A-2) a heavy
mineral oil having a kinematic viscosity at 100.degree. C. of 10 to
50 mm.sup.2/s in an amount of 0.5 to 40 percent by mass, based on
the total mass of the base oil.
4. The lubricating oil composition according to claim 1 which is
used for automatic transmission or continuously variable
transmissions.
5. The lubricating oil composition according to claim 1 which is
used for transmissions equipped with wet clutches and wet brakes.
Description
TECHNICAL FIELD
[0001] This invention relates to lubricating oil compositions and
more particularly to those which have excellent and long-lasting
anti-shudder properties and are capable of providing a long fatigue
life, suitable for automatic transmissions and/or continuously
variable transmissions.
BACKGROUND ART
[0002] Up to now, automatic transmissions have been required to
have thermal oxidation stability, anti-wear properties, and
friction characteristics for wet clutches. In order to enhance such
properties and characteristics, lubricants have been used which
contain a base oil suitably blended with various additives such as
anti-oxidants, detergent dispersants, anti-wear agents, friction
modifiers, seal swelling agents, viscosity index improvers,
antifoamers, dyes, and the like.
[0003] Recent automatic transmissions are desired to be light in
weight and compact in size and demanded to be enhanced in power
transmission capability, resulting from the increased output of
engines to be combined. Lubricants used in such automatic
transmissions are now demanded to possess properties capable of
preventing pitching (defects occurring when lubricated surfaces are
damaged) on surfaces of bearings and gears so as to prolong the
fatigue life thereof while maintaining high lubricating performance
properties.
[0004] In recent years, a control, so-called "slip lock-up control"
wherein the lock-up clutch equipped in a torque converter is given
a small degree of slip in a low speed range is employed in many of
automatic transmissions. The slip lock-up control can transmit
engine torque to a transmission mechanism efficiently while
improving the riding comfort by absorbing the torque fluctuation.
Some of continuously variable transmissions employ a so-called
"slip control" for effecting a smooth start from the stop state by
slipping and then engaging the wet starting clutch. In this
connection, lubricants are demanded to have excellent and
long-lasting anti-shudder properties for the slip control of such
lock-up clutches and starting clutches.
[0005] It is common knowledge that a lubricant containing
sulfur-based additives providing excellent extreme pressure
properties and anti-wear properties is effective in prolonging the
fatigue life of bearings, gears or the like. However, since the
sulfur-based additives are excellent in extreme pressure properties
but can not avoid wears caused by corrosion and abrasion due to
their strong activity to metal surfaces, the single use of such
additives may arise a problem.
[0006] In order to obtain anti-shudder properties and prolong the
duration thereof , it is necessary to add a suitable amount of a
friction modifier capable of maintaining the friction
characteristics of a lock-up clutch, to a lubricating oil. However,
the friction modifier is less effective in prolonging fatigue life
and will be decreased in anti-shudder maintaining effect at an
early stage due to a deterioration in oxidation stability of the
lubricating oil when the friction modifier is used in combination
with the above-described sulfur-based additive. That is, it has
been found difficult to achieve anti-pitching properties and
excellent and long-lasting anti-shudder properties with
conventional lubricating oils at the same time.
[0007] In view of the foregoing situations, the object of the
present invention is to provide a lubricating oil composition
having both anti-pitching properties capable of providing a
transmission with long fatigue life and sufficient and long-lasting
anti-shudder properties, particularly suitable for automatic
transmissions and/or continuously variable transmission.
DISCLOSURES OF THE INVENTION
[0008] According to the present invention, there is provided a
lubricating oil composition which comprises (A) a base oil, (B)
calcium salicylate having a base number of 50 to 300 mgKOH/g in an
amount of 0.005 to 0.07 percent by mass in terms of calcium, (C) an
SP type extreme pressure additive in an amount of 0.005 to 0.07
percent by mass in terms of phosphorous, (D) one or more compounds
selected from the group consisting of succinimide compounds
represented by formulas (3) and (4) below in an amount of 0.1 to 6
percent by mass, and (E) a boron-containing ashless dispersant in
an amount of 0.001 to 0.05 percent by mass in terms of boron, based
on the total mass of the composition: 1
[0009] wherein R.sup.1 is a straight-chain or branched hydrocarbon
group having 8 to 30 carbon atoms, R.sup.12 is hydrogen or a
hydrocarbon group having 1 to 30 carbon atoms, R.sup.13 is a
hydrocarbon group having 1 to 4 carbon atoms, and m is an integer
of from 1 to 7; 2
[0010] wherein R.sup.14 and R.sup.15 are each independently a
straight-chain or branched hydrocarbon group having 8 to 30 carbon
atoms, and R.sup.16 and R.sup.17 are each independently a
hydrocarbon group having 1 to 4 carbon atoms, and n is an integer
of from 1 to 7.
[0011] The present invention will be described in more details
below.
[0012] Lubricating base oils (A) used in the present invention may
be any mineral oils and/or synthetic oils which have conventionally
been used as base oils for lubricating oils.
[0013] Examples of such mineral base oil include paraffinic or
naphthenic oils which can be obtained by subjecting a lubricating
oil fraction produced by atmospheric- or vacuum-distilling a crude
oil, to any one or more refining processes selected from solvent
deasphalting, solvent extraction, hydrocracking, solvent dewaxing,
catalytic dewaxing, hydrorefining, washing with sulfuric acid, and
clay treatment; and n-paraffines.
[0014] Examples of synthetic base oils include poly-.alpha.-olefins
such as 1-octene oligomer, 1-decene oligomer, and
ethylene-propylene oligomer, and hydrides thereof; isobutene
oligomer and hydrides thereof; isoparaffines; alkylbenzenes;
alkylnaphthalenes; diesters such as ditridecyl glutarate,
di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate,
and di-2-ethylhexyl cebacate; polyol esters such as
trimethylolpropane caprylate, trimethylolpropane pelargonate,
pentaerythritol-2-ethyl hexanoate, and pentaerythritol pelargonate;
polyoxyalkylene glycols; dialkyldiphenyl ethers; and polyphenyl
ethers.
[0015] In order to further improve fatigue life, it is preferred to
use a mixture of two types of base oils having a different
kinematic viscosity, i.e., a mixture of (A-1) a mineral or
synthetic oil having a kinematic viscosity at 100.degree. C. of 2
to 6 mm.sup.2/s, or a mixture thereof and (A-2) a heavy mineral oil
having a kinematic viscosity at 100.degree. C. of 10 to 50
mm.sup.2/s, preferably 15 to 45 mm.sup.2/s. A base oil obtained by
mixing (A-1) and (A-2) oils has a kinematic viscosity at
100.degree. C. of 1 to 10 mm.sup.2/s, preferably 2 to 8
mm.sup.2/s.
[0016] The mix ratio of a base oil with a kinematic viscosity of
(A-1) to a base oil with a kinematic viscosity of (A-2) is
preferably 60 to 99.5:40 to 0.5 by mass, more preferably 65 to
95:35 to 5. A base oil of a kinematic viscosity of (A-2) in an
amount of less than 0.5 percent by mass would fail to obtain a
further improvement in fatigue life caused by addition of the heavy
base oil, while a base oil of a kinematic viscosity of (A-2) in an
amount of more than 40 percent by mass would deteriorate the
low-temperature fluidity of the resulting lubricating oil and thus
would adversely affect the low-temperature startability of a
transmission.
[0017] Examples of Component (B), i.e., calcium salicylate include
neutral calcium salicylates, basic calcium salicylates, carbonated
overbased calcium salicylates, borated overbased calcium
salicylates, and mixtures thereof.
[0018] No particular limitation is imposed on a method of producing
calcium salicylate. For example, a neutral calcium salicylate
mentioned above may be produced by reacting an alkyl salicylic acid
having one or two alkyl groups having 10 to 30, preferably 12 to
20, and more preferably 14 to 18 carbon atoms with a calcium base
such as an oxide or hydroxide of calcium, in the presence or
absence of sulfur. Examples of the alkyl group of the alkyl
salicylic acid include decyl, undecyl, dodecyl, tridecyl,
tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,
nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl,
pentacosyl, hexacosyl, heptacosyl, octacosyl, nonacosyl, and
triacontyl groups. Among these alkyl groups, preferred are
tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl
groups. A basic calcium salicylate as mentioned above may be
produced by heating a neutral calcium salicylate as mentioned above
and a calcium salt or base in an excess amount in the presence of
water. A carbonated overbased calcium salicylate as mentioned above
may be produced by reacting a neutral calcium salicylate as
mentioned above with a calcium base in the presence of carbon
dioxide gas. A borated overbased calcium salicylate may be produced
by reacting a neutral calcium salicylate as mentioned above with a
calcium base and a boric acid compound such as boric acid or
anhydrous boric acid or reacting a carbonated overbased calcium
salicylate as mentioned above with a boric acid compound such as
boric acid or anhydrous boric acid.
[0019] Component (B) is preferably a basic calcium salicylate
having a base number of 50 to 300 mgKOH/g, preferably 70 to 250
mgKOH/g. The term "base number" used herein denotes a base number
measured by the perchloric acid potentiometric titration method in
accordance with section 7 of JIS K2501 (1992) "Petroleum products
and lubricants-Determination of neutralization number". Component
(B) of a base number of less than 50 mgKOH/g would be less
effective in suppressing a wet clutch from being decreased in
strength against repeating compression applied thereto, while
Component (B) of a base number of more than 300 mgKOH/g would
deteriorate the storage stability of the resulting oil
composition.
[0020] The lower limit content of Component (B) is 0.005 percent by
mass, preferably 0.01 percent by mass while the upper limit content
of Component (B) is 0.07 percent by mass, preferably 0.06 percent
by mass. Component (B) of less than 0.005 percent by mass would be
less effective in friction modifying capability and shortened the
duration of anti-shudder properties. Component (B) of more than
0.07 percent by mass would cause a possibility that calcium salts
formed upon decomposition of Component (B), i.e., calcium
salicylate clog the hollow hole of a wet friction clutch and thus
change the friction coefficient.
[0021] Component (C) of the lubricating oil composition of the
present invention is an SP type extreme pressure additive. More
specifically, examples of Component (C) are phosphorus compounds
represented by formulas (1) and (2) and salts thereof: 3
[0022] wherein at least one of X.sup.1, X.sup.2, and X.sup.3 is
sulfur and the remainder is oxygen, and R.sup.1, R.sup.2, and
R.sup.3 are each independently hydrogen or a hydrocarbon group
having 1 to 30 carbon atoms; and 4
[0023] wherein X.sup.4, X.sup.5, and X.sup.6 are each independently
oxygen or sulfur, and R.sup.4, R.sup.5, and R.sup.6 are each
independently hydrogen or a hydrocarbon having 1 to 30 carbon
atoms.
[0024] Specific examples of hydrocarbons having 1 to 30 carbon
atoms for R.sup.1 to R.sup.6 include alkyl, cycloalkyl, alkenyl,
alkyl-substituted cycloalkyl, aryl, alkyl-substituted aryl, and
arylalkyl groups.
[0025] Examples of the alkyl group include straight-chain or
branched alkyl groups such as methyl, ethyl, propyl, butyl, pentyl,
hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl,
tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl
groups.
[0026] Examples of the cycloalkyl group include those having 5 to 7
carbon atoms, such as cyclopentyl, cyclohexyl, and cycloheptyl
groups. Examples of the alkylcycloalkyl groups include those having
6 to 11 carbon atoms, such as methylcyclopentyl,
dimethylcyclopentyl, methylethylcyclopentyl, diethylcyclopentyl,
methylcyclohexyl, dimethylcyclohexyl, methylethylcyclohexyl,
diethylcyclohexyl, methylcycloheptyl, dimethylcycloheptyl,
methylethylcycloheptyl, and diethylcycloheptyl groups, of which the
alkyl groups may bond to any position of the cycloalkyl groups.
[0027] Examples of the alkenyl group include butenyl, pentenyl,
hexenyl, heptenyl, octenyl, noneyl, decenyl, undecenyl, dodecenyl,
tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl,
and octadecenyl groups, all of which may be straight-chain or
branched and the position of which the double bonds may vary.
[0028] Examples of the aryl group include phenyl and naphtyl
groups. Examples of the alkylaryl group include those having 7 to
18 carbon atoms, such as tolyl, xylyl, ethylphenyl, propylphenyl,
butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl,
nonylphenyl, decylphenyl, undecylphenyl, and dodecylphenyl groups,
of which the alkyl groups may be straight-chain or branched and may
bond to any position of the aryl groups.
[0029] Examples of the arylalkyl groups include those having 7 to
12 carbon atoms, such as benzyl, phenylethyl, phenylpropyl,
phenylbutyl, phenylpentyl, and phenylhexyl groups, of which the
alkyl groups may be straight-chain or branched.
[0030] Hydrocarbon groups having 1 to 30 carbon atoms for R.sup.1
to R.sup.6 are preferably alkyl groups having 1 to 30 carbon atoms
and aryl groups having 6 to 24 carbon atoms, more preferably alkyl
groups having 4 to 20 carbon atoms, and further more preferably
alkyl groups having 6 to 18 carbon atoms.
[0031] Examples of SP type extreme pressure additives represented
by formula (1) include the following phosphorus compounds:
thiophosphite; monoalkylthiophosphites of which the alkyl group may
be straight-chain or branched, such as monopropylthiophosphite,
monobutylthiophosphite, monopentylthiophosphite,
monohexylthiophosphite, monoheptylthiophosphite,
monooctylthiophosphite, and monolaurylthiophosphite;
mono((alkyl)aryl)thiophosphites, such as monophenylthiophosphite
and monocresylthiophosphite; dialkylthiophosphites of which the
alkyl groups may be straight-chain or branched, such as
dipropylthiophosphite, dibutylthiophosphite, dipentylthiophosphite,
dihexylthiophosphite, diheptylthiophosphite, dioctylthiophosphite,
and dilaurylthiophosphite; di((alkyl)aryl)thiophosphite such as
diphenylthiophosphite and dicresylthiophosphite;
trialkylthiophosphites of which the alkyl groups may be
straight-chain or branched, such as tripropylthiophosphite,
tributylthiophosphite, tripentylthiophosphite,
trihexylthiophosphite, triheptylthiophosphite,
trioctylthiophosphite, and trilaurylthiophosphite;
tri((alkyl)aryl)thiophosphites such as triphenylthiophosphite and
tircresylthiophosphite; dithiophosphite; monoalkyldithiophosphites
of which the alkyl groups may be straight-chain or branched, such
as monopropyldithiophosphite, monobutyldithiophosphite,
monopentyldithiophosphite, monohexyldithiophosphite,
monoheptyldithiophosphite, monooctyldithiophosphite, and
monolauryldithiophosphite; mono((alkyl)aryl)dithiophosphites, such
as monophenyldithiophosphite and monocresyldithiophosphite;
dialkyldithiophosphites of which the alkyl groups may be
straight-chain or branched, such as dipropyldithiophosphite,
dibutyldithiophosphite, dipentyldithiophosphite,
dihexyldithiophosphite, diheptyldithiophosphite,
dioctyldithiophosphite, and dilauryldithiophosphite;
di((alkyl)aryl)dithiophosphite such as diphenyldithiophosphite and
dicresyldithiophosphite; trialkyldithiophosphites of which the
alkyl groups may be straight-chain or branched, such as
tripropyldithiophosphit- e, tributyldithiophosphite,
tripentyldithiophosphite, trihexyldithiophosphite,
triheptyldithiophosphite, trioctyldithiophosphite, and
trilauryldithiophosphite; tri((alkyl)aryl)dithiophosphites such as
triphenyldithiophosphite and tircresyldithiophosphite;
trithiophosphite; monoalkyltrithiophosphites of which the alkyl
groups may be straight-chain or branched, such as
monopropyltrithiophosphite, monobutyltrithiophosphite,
monopentyltrithiophosphite, monohexyltrithiophosphite,
monoheptyltrithiophosphite, monooctyltrithiophosphite, and
monolauryltrithiophosphite; mono((alkyl)aryl)trithiophosphites,
such as monophenyltrithiophosphite and monocresyltrithiophosphite;
dialkyltrithiophosphites of which the alkyl groups may be
straight-chain or branched, such as dipropyltrithiophosphite,
dibutyltrithiophosphite, dipentyltrithiophosphite,
dihexyltrithiophosphite, diheptyltrithiophosphite,
dioctyltrithiophosphite, and dilauryltrithiophosphite;
di((alkyl)aryl)trithiophosphite such as diphenyltrithiophosphite
and dicresyltrithiophosphite; trialkyltrithiophosphites of which
the alkyl groups may be straight-chain or branched, such as
tripropyltrithiophosphite, tributyltrithiophosphite,
tripentyltrithiophosphite, trihexyltrithiophosphite,
triheptyltrithiophosphite, trioctyltrithiophosphite, and
trilauryltrithiophosphite; tri((alkyl)aryl)trithiophosphites such
as triphenyltrithiophosphite and tircresyltrithiophosphite; and
mixtures thereof.
[0032] In the present invention, preferably two or more of X.sup.1
to X.sup.3 are sulfur, and more preferably all of X.sup.1 to X3 are
sulfur.
[0033] Examples of SP type extreme pressure additives represented
by formula (2) include the following phosphorus compounds:
thiophosphate; monoalkylthiophosphates of which the alkyl groups
may be straight-chain or branched, such as monopropylthiophosphate,
monobutylthiophosphate; monopentylthiophosphate,
monohexylthiophosphate, monoheptylthiophosphate,
monooctylthiophosphate, and monolaurylthiophosphate;
mono((alkyl)aryl)thiophosphates, such as monophenylthiophosphate
and monocresylthiophosphate; dialkylthiophosphates of which the
alkyl groups may be straight-chain or branched, such as
dipropylthiophosphate, dibutylthiophosphate, dipentylthiophosphate,
dihexylthiophosphate, diheptylthiophosphate, dioctylthiophosphate,
and dilaurylthiophosphate; di((alkyl)aryl)thiophosphate such as
diphenylthiophosphate and dicresylthiophosphate;
trialkylthiophosphates of which the alkyl groups may be
straight-chain or branched, such as tripropylthiophosphate,
tributylthiophosphate, tripentylthiophosphate,
trihexylthiophosphate, triheptylthiophosphate,
trioctylthiophosphate, and trilaurylthiophosphate;
tri((alkyl)aryl)thiophosphates such as triphenylthiophosphate and
tircresylthiophosphate; dithiophosphate; monoalkyldithiophosphates
of which the alkyl group may be straight-chain or branched, such as
monopropyldithiophosphate, monobutyldithiophosphate;
monopentyldithiophosphate, monohexyldit.hiophosphate,
monoheptyldithiophosphate, monooctyldithiophosphate, and
monolauryldithiophosphate; mono((alkyl)aryl)dithiophosphates, such
as monophenyldithiophosphate and monocresyldithiophosphate;
dialkyldithiophosphates of which the alkyl groups may be
straight-chain or branched, such as dipropyldithiophosphate,
dibutyldithiophosphate, dipentyldithiophosphate,
dihexyldithiophosphate, diheptyldithiophosphate,
dioctyldithiophosphate, and dilauryldithiophosphate;
di((alkyl)aryl)dithiophosphates such as diphenyldithiophosphate and
dicresyldithiophosphate; trialkyldithiophosphates of which the
alkyl groups may be straight-chain or branched, such as
tripropyldithiophosphat- e, tributyldithiophosphate,
tripentyldithiophosphate, trihexyldithiophosphate,
triheptyldithiophosphate, trioctyldithiophosphate, and
trilauryldithiophosphate; tri((alkyl)aryl)dithiophosphates such as
triphenyldithiophosphate and tircresyldithiophosphate;
trithiophosphate; monoalkyltrithiophosphates of which the alkyl
groups may be straight-chain or branched, such as
monopropyltrithiophosphate, monobutyltrithiophosphate;
monopentyltrithiophosphate, monohexyltrithiophosphate,
monoheptyltrithiophosphate, monooctyltrithiophosphate, and
monolauryltrithiophosphate; mono((alkyl)aryl)trithiophosphates,
such as monophenyltrithiophosphate and monocresyltrithiophosphate;
dialkyltrithiophosphates of which the alkyl groups may be
straight-chain or branched, such as dipropyltrithiophosphate,
dibutyltrithiophosphate, dipentyltrithiophosphate,
dihexyltrithiophosphate, diheptyltrithiophosphate,
dioctyltrithiophosphate, and dilauryltrithiophosphate;
di((alkyl)aryl)trithiophosphates such as diphenyltrithiophosphate
and dicresyltrithiophosphate; trialkyltrithiophosphates of which
the alkyl groups may be straight-chain or branched, such as
tripropyltrithiophosphate, tributyltrithiophosphate,
tripentyltrithiophosphate, trihexyltrithiophosphate,
triheptyltrithiophosphate, trioctyltrithiophosphate, and
trilauryltrithiophosphate; tri((alkyl)aryl)trithiophosphates such
as triphenyltrithiophosphate and tircresyltrithiophosphate;
tetrathiophosphate; monoalkyltetrathiophosphates of which the alkyl
groups may be straight-chain or branched, such as
monopropyltetrathiopho.- sphate, monobutyltetrathiophosphate;
monopentyltetrathiophosphate, monohexyltetrathiophosphate,
monoheptyltetrathiophosphate, monooctyltetrathiophosphate, and
monolauryltetrathiophosphate; mono((alkyl)aryl)tetrathiophosphates,
such as monophenyltetrathiophosphat- e and
monocresyltetrathiophosphate; dialkyltetrathiophosphates of which
the alkyl groups may be straight-chain or branched, such as
dipropyltetrathiophosphate, dibutyltetrathiophosphate,
dipentyltetrathiophosphate, dihexyltetrathiophosphate,
diheptyltetrathiophosphate, dioctyltetrathiophosphate, and
dilauryltetrathiophosphate; di((alkyl)aryl)tetrathiophosphates such
as diphenyltetrathiophosphate and dicresyltetrathiophosphate;
trialkyltetrathiophosphates of which the alkyl groups may be
straight-chain or branched, such as tripropyltetrathiophosphate,
tributyltetrathiophosphate, tripentyltetrathiophosphate,
trihexyltetrathiophosphate, triheptyltetrathiophosphate,
trioctyltetrathiophosphate, and trilauryltetrathiophosphate;
tri((alkyl)aryl)tetrathiophosphates such as
triphenyltetrathiophosphate and tircresyltetrathiophosphate; and
mixtures thereof.
[0034] In the present invention, preferably one to three of X.sup.4
to X.sup.6 are sulfur, and more preferably one or two of X.sup.4 to
X.sup.6 are sulfur.
[0035] Examples of salts of phosphorus compounds represented by
formula (1) or (2) are those obtained by allowing a phosphorus
compound to react with a nitrogen-containing compound such as
ammonia or an amine compound having in its molecules only
hydrocarbon or hydroxyl-containing hydrocarbon groups having 1 to 8
carbon atoms so as to neutralize the whole or part of the remaining
acid hydrogen.
[0036] Specific examples of the nitrogen-containing compound are
ammonia; alkylamines, of which the alkyl groups may be
straight-chain or branched, such as monomethylamine,
monoethylamine, monopropylamine, monobutylamine, monopentylamine,
monohexylamine, monoheptylamine, monooctylamine, dimethylamine,
methylethylamine, diethylamine, methylpropylamine,
ethylpropylamine, dipropylamine, methylbutylamine, ethylbutylamine,
propylbutylamine, dibutylamine, dipentylamine, dihexylamine,
diheptylamine and dioctylamine; alkanolamines, of which the alkanol
groups may be straight-chain or branched, such as
monomethanolamine, monoethanolamine, monopropanolamine,
monobutanolamine, monopentanolamine, monohexanolamine,
monoheptanolamine, monooctanolamine, monononanolamine,
dimethanolamine, methanolethanolamine, diethanolamine,
methanolpropanolamine, ethanolpropanolamine, dipropanolamine,
methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine,
dibutanolamine, dipentanolamine, dihexanolamine, diheptanolamine
and dioctanolamine; and mixtures thereof.
[0037] One or more of these Components (C) may be blended
arbitrarily.
[0038] The use of Component (C) makes it possible to provide not
only anti-wear properties but also optimized friction
characteristics for a wet clutch.
[0039] The lubricating oil composition of the present invention
contains Component (C) in an amount of 0.005 percent by mass or
more, preferably 0.008 percent by mass or more and 0.07 percent by
mass or less, preferably 0.06 percent by mass or less, in terms of
phosphorus based on the total mass of the composition. Component
(C) of less than 0.005 percent would be ineffective in anti-wear
properties, while Component (C) in excess of 0.07 percent by mass
would be prone to cause pitching.
[0040] Component (D) of the lubricating oil composition of the
present invention is a succinimide compound represented by formula
(3) or (4) below: 5
[0041] wherein R.sup.11 is a straight-chain or branched hydrocarbon
having 8 to 30 carbon atoms, R.sup.12 is hydrogen or a hydrocarbon
group having 1 to 30 carbon atoms, R.sup.13 is a hydrocarbon group
having 1 to 4 carbon atoms, and m is an integer of from 1 to 7; and
6
[0042] wherein R.sup.14 and R.sup.15 are each independently a
straight-chain or branched hydrocarbon group having 8 to 30 carbon
atoms, R.sup.16 and R.sup.17 are each independently a hydrocarbon
group having 1 to 4 carbon atoms, and n is an integer of from 1 to
7.
[0043] R.sup.11 in formula (3) and R.sup.14 and R.sup.15 in formula
(4) are each independently a straight-chain or branched hydrocarbon
group having 8 to 30, preferably 12 to 25 carbon atoms. Examples of
such a hydrocarbon group are include alkyl and alkenyl groups.
Preferred are alkyl groups. Examples of the alkyl groups are octyl,
octenyl, nonyl, nonenyl, decyl, decenyl, dodecyl, dodecenyl,
octadecyl, octadecenyl, and straight-chain or branched alkyl groups
having up to 30 carbon atoms. A hydrocarbon group having fewer than
8 carbon atoms or more than 30 carbon atoms would be ineffective in
anti-shudder vibration. Preferred are branched alkyl groups having
8 to 30 carbon atoms, and particularly preferred are branched alkyl
groups having 10 to 25 carbon atoms. A branched alkyl group having
8 to 30 carbon atoms results in a lubricating oil composition
exhibiting a higher torque capacity than a straight-chain alkyl
group.
[0044] R.sup.13 in formula (3) and R.sup.16 and R.sup.17 in formula
(4) are each independently a hydrocarbon group having 1 to 4 carbon
atoms. Examples of such a hydrocarbon include alkylene groups
having 1 to 4 carbon atoms, preferably alkylene groups having 2 or
3 carbon atoms (ethylene, propylene).
[0045] R.sup.12 in formula (3) is hydrogen or a straight-chain or
branched hydrocarbon group having 1 to 30 carbon atoms. Examples of
such a straight-chain or branched hydrocarbon group include
straight-chain or branched alkyl or alkenyl groups having 1 to 30
carbon atoms. Preferred are branched alkyl or alkenyl groups having
1 to 30 carbon atoms, more preferred are branched alkyl or alkenyl
groups having 8 to 30 carbon atoms, and further more preferred are
branched alkyl or alkenyl groups having 10 to 25 carbon atoms.
Particularly preferred are branched alkyl groups.
[0046] In formulas (3) and (4), m and n are each independently an
integer of from 1 to 7. In order to obtain a lubricating oil
composition exhibiting a higher torque capacity, m and n are each
independently preferably 1, 2, or 3, particularly preferably 1.
[0047] A succinimide compound represented by formula (3). or (4)
may be produced by a conventional method. For example, such a
succinimide compound may be produced by reacting an alkyl or
alkenyl succinic anhydride with a polyamine. More specifically, a
monosuccinimide of formula (3) wherein R.sup.12 is hydrogen may be
obtained by adding dropwise 1 mole of a succinic anhydride having a
straight-chain or branched alkyl or alkenyl group having 8 to 30
carbon atoms to 1 mole or more of a polyamine such as
diethylenetriamine, triethylenetetramine, and
tetraethylenepentamine under a nitrogen atmosphere at a temperature
of 130 to 180.degree. C., preferably 140 to 175.degree. C. for 1 to
10 hours, preferably 2 to 6 hours and by distilling out the
unreacted polyamine. A monosuccinimide of formula (3) wherein
R.sup.12 is a hydrocarbon group having 1 to 30 carbon atoms may be
obtained by reacting N-octadecyl-1,3-propanediamine with succinic
anhydride as described above by the same method as described above.
A bis succinimide represented by formula (4) may be obtained by
reacting 0.5 mol of a polyamine as mentioned above with 1 mol of
succinic anhydride as described above under the same reaction
conditions as described above and removing the water generated.
[0048] In the present invention, Component (D) is preferably a
bis-type succinimide represented by formula (4) because the use of
a bis-type succinimide is contributive to the production of a
lubricating oil composition with a higher torque transmission
capacity, compared with a mono-type succinimide represented by
formula (3).
[0049] The content of Component (D) in the lubricating oil
composition of the present invention is 0.1 percent by mass or
more, preferably 0.2 percent by mass or more, based on the total
mass of the composition. The content of Component (D) is 6 percent
by mass or less, preferably 4 percent by mass or less, based on the
total mass of the composition. Component (D) of less than 0.1
percent by mass would be ineffective in maintaining excellent
anti-shudder properties and shifting properties, while Component
(D) in excess of 6 percent by mass would fail to attain effects as
expected.
[0050] Component (E) of the lubricating oil composition of the
present invention is a boron-containing ashless dispersant.
Component (E) importantly contains boron. In the case where a
boron-free ashless dispersant is used as Component (E), it can not
achieve the purposes of the present invention because it not only
fails to inhibit fatigue caused by pitching or flaking and provide
anti-shudder properties but also becomes ineffective in anti-wear
properties and oxidation stability as a lubricating oil composition
even though it is used in combination with Components (B) and
(C)
[0051] Specific examples of Component (E) include modified products
obtained by modifying a nitrogen-containing compounds or derivative
thereof, having at least one alkyl or alkenyl group having 40 to
400 carbon atoms in the molecules, with a boron compound. Any one
or more kinds selected from these compounds may be blended.
[0052] The alkyl or alkenyl group may be straight-chain or branched
but is preferably a branched alkyl or alkenyl group derived from an
oligomer of an olefin such as propylene, 1-butene, and isobutylene
or a cooligomer of ethylene and propylene.
[0053] Although the carbon number of the alkyl or alkenyl group is
optional, it is preferably 40 to 400, more preferably 60 to 350
carbon atoms. An alkyl or alkenyl group having fewer than 40 carbon
atoms would deteriorate the solubility of the compound in a base
oil, while an alkyl or alkenyl group having more than 400 carbon
atoms would deteriorate the low-temperature fluidity of the
resulting lubricating oil composition.
[0054] Specific examples of the above-mentioned nitrogen-containing
compound or derivative include any one or more kinds of compounds
selected from:
[0055] (E-1) succinimides having at least one alkyl or alkenyl
group having 40 to 400 carbon atoms in the molecules or derivatives
thereof;
[0056] (E-2) benzylamines having at least one alkyl or alkenyl
group having 40 to 400 carbon atoms in the molecules or derivatives
thereof; and
[0057] (E-3) polyamines having at least one alkyl or alkenyl group
having 40 to 400 carbon atoms in the molecules or derivatives
thereof.
[0058] Specific examples of (E-1) succinimides are those
represented by the following formulas: 7
[0059] In formula (5), R.sup.21 is an alkyl or alkenyl group having
40 to 400, preferably 60 to 350 carbon atoms, and a is an integer
of from 1 to 5, preferably 2 to 4.
[0060] In formula (6), R.sup.22 and R.sup.23 are each independently
an alkyl or alkenyl group having 40 to 400, preferably 60 to 350
carbon atoms, and b is an integer of from 0 to 4, preferably 1 to
3.
[0061] Mono-type succinimides represented by formula (5) and
bis-type succinimides represented by formula (6) may be used
singlely or in combination.
[0062] Specific examples of (E-2) benzylamines are compounds
represented by the formula 8
[0063] In formula (7), R.sup.24 is an alkyl or alkenyl group having
40 to 400, preferably 60 to 350 carbon atoms, and c is an integer
of from 1 to 5, preferably 2 to 4.
[0064] No particular limitation is imposed on the method of
producing the benzylamines. However, for example, one of the
benzylamines may be produced by reacting a polyolefin such as
propylene oligomer, polybutene, or an ethylene-.alpha.-olefin
copolymer with a phenol so as to obtain an alkylphenol, followed by
a Mannich reaction thereof with formaldehyde and a polyamine such
as diethylenetriamine, triethylenetetramine,
tetraethylenepentamine, or pentaethylenehexamine.
[0065] Specific examples of (E-3) polyamines are compounds
represented by the formula
R.sup.25--NH--(CH.sub.2CH.sub.2NH).sub.d--H (8)
[0066] In formula (8), R.sup.25 is an alkyl or alkenyl group having
40 to 400, preferably 60 to 350 carbon atoms, and d is an integer
of from 1 to 5, preferably 2 to 4.
[0067] No particular limitation is imposed on the method of
producing the polyamines represented by formula (8). For example,
one of the polyamines may be produced by subjecting a polyolefin
such as propylene oligomer, polybutene, or an
ethylene-.alpha.-olefin copolymer to chloridization, followed by a
reaction thereof with ammonia or a polyamine such as
ethylenediamine, diethylenetriamine, triethylenetetramine,
tetraethylenepentamine, or pentaethylenehexamine.
[0068] Specific examples of the derivatives of the nitrogen
compounds (E-1) to (E-3) are carboxylic acid-modified compounds
obtained by allowing any one of the aforesaid nitrogen compounds to
react with a monocarboxylic acid (fatty acid) having 2 to 30 carbon
atoms or a polycarboxylic acid having 2 to 30 carbon atoms, such as
oxalic acid, phthalic acid, trimellitic acid, or pyromellitic acid
so as to neutralize or amidize the whole or part of the remaining
amino and/or imino groups; sulfur-modified compounds obtained by
allowing any one of the aforesaid nitrogen compounds to react with
a sulfuric compound; and mixtures thereof.
[0069] Component (E) used in the present invention is a compound
obtained by modifying any one of the aforesaid nitrogen-containing
compounds or a derivative thereof with a boron compound.
[0070] No particular limitation is imposed on the method of
modifying the nitrogen compounds or derivatives thereof with a
boron compound. Therefore, any suitable method may be employed. For
example, any one of the aforesaid nitrogen compounds or derivatives
thereof is reacted with a boron compound such as boric acid, a
borate, or a boric acid ester so as to neutralize or amidize the
whole or part of the amino and/or imino groups remaining in the
nitrogen compound or derivative thereof.
[0071] Specific examples of the boron compounds used herein include
orthoboric acid, methaboric acid, and tetraboric acid. Examples of
borates include alkali metal salts, alkaline earth metal salts, or
ammonium salts of boric acid. More specific examples include
lithium borate such as lithium methaborate, lithium tetraborate,
lithium pentaborate, and lithium perborate; sodium borate such as
sodium methaborate, sodium diborate, sodium tetraborate, sodium
pentaborate, sodium hexaborate, and sodium octaborate; potassium
borate such as potassium methaborate, potassium tetraborate,
potassium pentaborate, potassium hexaborate, and potassium
octaborate; calcium borate such as calcium methaborate, calcium
diborate, tricalcium tetraborate, pentacalcium tetraborate, and
calcium hexaborate; magnesium borate such as magnesium methaborate,
magnesium diborate, trimagnesium tetraborate, pentamagnesium
tetraborate, and magnesium hexaborate; and ammonium borate such as
ammonium methaborate, ammonium tetraborate, ammonium pentaborate,
and ammonium octaborate. Examples of the boric acid esters include
esters of boric acid and an alkyl alcohol having 1 to 6 carbon
atoms and more specifically monomethyl borate, dimethyl borate,
trimethyl borate, monoethyl borate, diethyl borate, triethyl
borate, monopropyl borate, dipropyl borate, tripropyl borate,
monobutyl borate, dibutyl borate, and tributyl borate.
[0072] No particular limitation is imposed on the boron content in
Component (E). However, the boron content is preferably 0.2 percent
by mass or more, more preferably 0.4 percent by mass or more and
preferably 4 percent by mass or less, more preferably 2.5 percent
by mass or less in order to obtain long fatigue life and excellent
anti-wear properties.
[0073] Preferred for Component (E) are those obtained by modifying
(E-1) succinimides having at least one alkyl or alkenyl group
having 40 to 400 carbon atoms per molecule or derivatives thereof
used as the aforesaid nitrogen-containing compounds with the
aforesaid boron compounds; and mixtures thereof with the objective
of improved fatigue life and anti-wear properties.
[0074] The content of Component (E) in the lubricating oil
composition of the present invention is 0.001 percent by mass or
more, preferably 0.002 percent by mass or more in terms of boron,
based on the total mass of the composition and 0.05 percent by mass
or less, preferably 0.03 percent bymass or less in terms of boron,
based on the total mass of the composition. Component (E) of less
than 0.001 percent would be ineffective in preventing pitching or
flaking, while Component (E) of more than 0.05 percent by mass
would deteriorate the oxidation stability of the resulting
composition.
[0075] The lubricating oil composition of the present invention may
be blended with known additives for the purpose of further
enhancing its functions as a lubricating oil. Examples of such
additives include (F) phosphorus extreme pressure additives, (G)
boron-free ashless dispersants, (H) metal detergents other than
Component (B), (I) friction modifiers, (J) anti-oxidants, (K)
viscosity index improvers, (L) antifoamers, (M) rust preventives,
(N) corrosion inhibitors, (O) pour-point depressants, and (P)
rubber swelling agents. These additives may be used singlely or in
combination.
[0076] Addition of Component (F), i.e., phosphorus extreme pressure
additives to the lubricating oil composition of the present
invention is preferable because it can favorably maintain anti-wear
properties for gears and friction characteristics for wet
clutches.
[0077] Examples of the phosphorus extreme pressure additives
include zinc alkyldithiophosphates, phosphoric acid, phosphorous
acid, monophosphates, diphosphates, triphosphates, monophosphites,
diphosphites, triphosphites, salts of phosphates and phosphites,
and mixtures thereof.
[0078] Among these phosphorus extreme pressure additives, those
other than phosphoric acid and phosphorus acid are compounds
containing a hydrocarbon group having 2 to 30, preferably 3 to 20
carbon atoms.
[0079] Examples of hydrocarbon groups having 2 to 30 carbon atoms
include alkyl groups such as ethyl, propyl, butyl, pentyl, hexyl,
heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl,
tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl
groups, all of which may be straight-chain or branched; alkenyl
groups such as butenyl, pentenyl, hexenyl, heptenyl, octenyl,
nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl,
pentadecenyl, hexadecenyl, heptadecenyl and octadecenyl groups, all
of which may be straight-chain or branched and the position of
which the double bonds may vary; cycloalkyl groups having 5 to 7
carbon atoms, such as cyclopentyl, cyclohexyl, and cycloheptyl
groups; alkylcycloalkyl groups having 6 to 11 carbon atoms, such as
methylcyclopentyl, dimethylcyclopentyl, methylethylcyclopentyl,
diethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl,
methylethylcyclohexyl, diethylcyclohexyl, methylcycloheptyl,
dimethylcycloheptyl, methylethylcycloheptyl and diethylcycloheptyl
groups, of which the cycloalkyl groups may possess an alkyl
substituent at any position; aryl groups such as phenyl and
naphthyl; alkylaryl groups having 7 to 18 carbon atoms, such as
tolyl, xylyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl,
hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl,
undecylphenyl, and dodecylphenyl groups, all of which the alkyl
groups may be straight-chain or branched and may bond to any
position of the aryl group; and arylalkyl groups having 7 to 12
carbon atoms, such as benzyl, phenylethyl, phenylpropyl,
phenylbutyl, phenylpentyl and phenylhexyl groups, all of which
alkyl groups may be straight-chain or branched.
[0080] Preferred compounds as Component (F) are phosphoric acid;
phosphorus acid; zinc alkyldithiophosphates, of which the alkyl
groups may be straight-chain or branched, such as zinc
dipropyldithiophosphate, zinc dibutyldithiophosphate, zinc
dipentyldithiophosphate, zinc dihexyldithiophosphate, zinc
diheptyldithiophosphate, and zinc dioctyldithiophosphate; monoalkyl
phosphates, of which the alkyl groups may be straight-chain or
branched, such as monopropyl phosphate, monobutyl phosphate,
monopentyl phosphate, monohexyl phosphate, monoheptyl phosphate,
and monooctyl phosphate; mono(alkyl)aryl phosphates such as
monophenyl phosphate and monocresyl phosphate; dialkyl phosphates,
of which the alkyl groups may be straight-chain or branched, such
as dipropyl phosphate, dibutyl phosphate, dipentyl phosphate,
dihexyl phosphate, diheptyl phosphate, and dioctyl phosphate;
di(alkyl)aryl phosphates such as diphenyl phosphate and dicresyl
phospahte; trialkyl phosphates, of which the alkyl groups may be
straight-chain or branched, such as tripropyl phosphate, tributyl
phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl
phosphate, and trioctyl phosphate; tri(alkyl)aryl phosphates such
as triphenyl phosphate and tricresyl phosphate; monoalkyl
phosphites, of which the alkyl groups may be straight-chain or
branched, such as monopropyl phosphite, monobutyl phosphite,
monopentyl phosphite, monohexyl phosphite, monoheptyl phosphite,
and monooctyl phosphite; mono(alkyl)aryl phosphites such as
monophenyl phosphite and monocresyl phosphite; dialkyl phosphites,
of which the alkyl groups may be straight-chain or branched, such
as dipropyl phosphite, dibutyl phosphite, dipentyl phosphite,
dihexyl phosphite, diheptyl phosphite, and dioctyl phosphite;
di(alkyl)aryl phosphites such as diphenyl phosphite and dicresyl
phosphite; trialkyl phosphites, of which the alkyl groups may be
straight-chain or branched, such as tripropyl phosphite, tributyl
phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl
phosphite, and trioctyl phosphite; tri(alkyl)aryl phosphites, such
as triphenyl phosphite and tricresyl phosphite; and mixtures
thereof.
[0081] Specific examples of salts of phosphates and phosphites
include those obtained by allowing monophosphate, diphosphate,
monophosphite, or diphosphite to react with a nitrogen compound
such as ammonia or an amine compound having in its molecules only a
hydrocarbon group or hydroxyl-containing hydrocarbon group having 1
to 8 carbon atoms so as to neutralize the whole or part of the
remaining acid hydrogen.
[0082] Specific examples of the nitrogen compound include ammonia;
alkylamines, of which the alkyl groups may be straight-chain or
branched, such as monomethylamine, monoethylamine, monopropylamine,
monobutylamine, monopentylamine, monohexylamine, monoheptylamine,
monooctylamine, dimethylamine, methylethylamine, diethylamine,
methylpropylamine, ethylpropylamine, dipropylamine,
methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine,
dipentylamine, dihexylamine, diheptylamine, and dioctylamine;
alkanolamines, of which the alkanol groups may be straight-chain or
branched, such as monomethanolamine, monoethanolamine,
monopropanolamine, monobutanolamine, monopentanolamine,
monohexanolamine, monoheptanolamine, monooctanolamine,
monononanolamine, dimethanolamine, methanolethanolamine,
diethanolamine, methanolpropanolamine, ethanolpropanolamine,
dipropanolamine, methanolbutanolamine, ethanolbutanolamine,
propanolbutanolamine, dibutanolamine, dipentanolamine,
dihexanolamine, diheptanolamine, and dioctanolamine; and mixtures
thereof.
[0083] One or more Components (F) may be arbitrarily added to the
lubricating oil composition of the present invention.
[0084] No particular limitation is imposed on the content of
Component (F). However, the lubricating oil composition preferably
contains Component (F) in an amount of 0.005 to 0.2 percent by mass
in terms of phosphorus, based on the total mass of the composition.
Component (F) in an amount of less than 0.005 percent by mass would
be ineffective in anti-wear properties, while Component (F) in an
amount of more than 0.2 percent by mass would deteriorate the
oxidation stability.
[0085] The lubricating oil composition of the present invention
preferably contains Component (G), i.e., boron-free ashless
dispersants with the objective of improving wet friction
characteristics, friction characteristics for wet clutches,
inhibition of deterioration by oxidation while a lubricating oil is
used, and dispersibility of insolubles.
[0086] Boron-free ashless dispersants which may be added are
ashless dispersants which are compounds before being modified with
a boron compound as described with respect to Component (E). In the
present invention, one or more kinds of compounds selected from
such ashless dispersants may be blended in an arbitrary amount. The
content of boron-free ashless dispersants is preferably from 0.1 to
10 percent by mass, based on the total mass of the lubricating oil
composition.
[0087] Component (H), i.e., metal detergents other than Component
(B), which may be used in combination with the lubricating oil
compositions of the present invention may be any compounds which
are usually used as metal detergents in a lubricating oil. For
example, there may be used alkali metal or alkaline earth metal
sulfonates, alkali metal or alkaline earth metal phenates, and
alkali metal or alkaline earth metal naphthenates. One or more
these compounds may be used in combination. Examples of alkali
metals include sodium and potassium, while examples of alkaline
earth metals include calcium and magnesium. Specific preferred
examples of the metal detergents are calcium sulfonate, magnesium
sulfonate, calcium phenate, and magnesium phenate. The base number
and blend amount of these metal detergents are arbitrarily selected
depending on the requisite performance characteristics of a
lubricating oil.
[0088] Component (I), i.e., friction modifiers which may be used in
combination with the lubricating oil compositions of the present
invention may be any compounds which are usually used as friction
modifiers in a lubricating oil. For example, there may be used
amine compounds, fatty acid esters, fatty acid amides, and fatty
acid metal salts, all having in the molecules at least one alkyl or
alkenyl group having 6 to 30 carbon atoms, preferably at least one
straight-chain alkyl or alkenyl group having 6 to 30 carbon
atoms.
[0089] Examples of amine compounds include straight-chain or
branched, preferably straight-chain aliphatic monoamines having 6
to 30 carbon atoms, straight-chain or branched, preferably
straight-chain aliphatic polyamines having 6 to 30 carbon atoms,
and alkyleneoxide adducts of these aliphatic amines. Examples of
fatty acid esters include esters of straight-chain or branched,
preferably straight-chain fatty acids having 7 to 31 carbon atoms
and aliphatic monohydric alcohols or aliphatic polyhydric alcohols.
Examples of fatty acid amides include amides of straight-chain or
branched, preferably straight-chain fatty acids having 7 to 31
carbon atoms and aliphatic monoamines or aliphatic polyamines.
Examples of fatty acid metal salts include alkaline earth metal
salts (magnesium salts and calcium salts) or zinc salts of
straight-chain or branched, preferably straight-chain fatty acids
having 7 to 31 carbon atoms.
[0090] Although in the present invention, one or more compounds
selected from the above-described friction modifiers may be blended
in an arbitrary ratio, the content of thereof is generally within
the range of 0.01 to 5.0 percent by mass, preferably 0.03 to 3.0
percent by mass, based on the total amount of the lubricating oil
composition.
[0091] Component (J), i.e., anti-oxidants which may be used in
combination with the lubricating oil compositions of the present
invention may be any conventional ones such as phenol-based
compounds or amine-based compounds which are usually used as
anti-oxidants for a lubricating oil.
[0092] Specific examples of oxidation inhibitors include
alkylphenols such as 2-6-di-tert-butyl-4-methylphenol; bisphenols
such as methylene-4,4-bisphenol(2,6-di-tert-butyl-4-methyl phenol);
naphtylamines such as phenyl-.alpha.-naphtylamine;
dialkyldiphenylamines; zinc dialkyldithiophosphates such as zinc
di-2-ethylhexyldithiophosphate; and esters of
(3,5-di-tert-butyl-4-hydroxyphenyl) fatty acid such as propionic
acid and monohydric or polyhydric alcohols such as methanol,
octadecanol, 1,6-hexanediol, neopentyl glycol, thiodiethylene
glycol, triethylene glycol, and pentaerythritol.
[0093] Although in the present invention, one or more compounds
selected from the above-described anti-oxidants may be blended in
an arbitrary ratio, the content of thereof is generally within the
range of 0.01 to 5.0 percent by mass, based on the total amount of
the lubricating oil composition.
[0094] Component (K), i.e., viscosity index improvers which may be
used in combination with the lubricating oil compositions of the
present invention may be non-dispersion type viscosity index
improvers such as polymers or copolymers of one or more monomers
selected from various methacrylates or hydrides thereof and
dispersion type viscosity index improvers such as copolymers of
various methacrylates further containing nitrogen compounds.
Another examples of viscosity index improvers are non-dispersion-
or dispersion-type ethylene-.alpha.-olefin copolymers of which the
.alpha.-olefin may be propylene, 1-butene, or 1-pentene, or the
hydrides thereof, polyisobutylenes or the hydrogenated products
thereof, styrene-diene hydrogenated copolymers, styrene-maleate
anhydride copolymers, and polyalkylstyrenes.
[0095] It is necessary to select the molecular weight of these
viscosity index improvers considering the shear stability thereof.
Specifically, the number-average molecular weight of non-dispersion
or dispersion type polymethacrylates is preferably from 5,000 to
150,000, and more preferably from 5,000 to 35,000. The
number-average molecular weight of polyisobutylenes or hydrides
thereof is from 800 to 5,000, preferably from 1,000 to 4,000. The
number-average molecular weight of ethylene-.alpha.-olefin
copolymers and hydrides thereof is from 800 to 150,000, preferably
from 3,000 to 12,000.
[0096] Among these viscosity index improvers, the use of
ethylene-.alpha.-olefin copolymers or hydrides thereof is
contributive to production of a lubricating oil composition which
is excellent particularly in shear stability.
[0097] Although in the present invention, one or more compounds
selected from the above-described viscosity index improvers may be
blended in an arbitrary ratio, the content of thereof is generally
within the range of 0.1 to 40 percent by mass, based on the total
amount of the lubricating oil composition.
[0098] Component (L), i.e., anti-foamers which may be used in
combination with the lubricating oil compositions of the present
invention may be any conventional ones which are usually used as
anti-foamers for a lubricating oil. Specific examples of
anti-foamers include silicones such as dimethylsilicone and
fluorosilicone. Although in the present invention, one or more
compounds selected from the above-described anti-foamers may be
blended in an arbitrary ratio, the content of thereof is generally
within the range of 0.001 to 0.05 percent by mass, based on the
total amount of the lubricating oil composition.
[0099] Examples of Component (M), i.e., rust preventives include
alkenyl succinic acids, alkenyl succinic acid esters, polyhydric
alcohol esters, petroleum sulfonates, and
dinonylnaphthalenesulfonate.
[0100] Examples of Component (N), i.e., corrosion inhibitors
include benzotriazole-, tolyltriazole-, and imidazole-based
compounds.
[0101] Examples of Component (0), i.e., pour-point depressants
include polymethacrylate-based polymers, which are adaptable to a
lubricating base oil to be used.
[0102] Examples of Component (P), i.e., rubber swelling agents
include aromatic compounds.
[0103] In the present invention, the contents of Components (M),
(N), (0), and (P) may be arbitrarily selected. However, in general,
the content of the corrosion inhibitors, is from 0.005 to 0.2
percent by mass, based on the total mass of the composition. The
content of the other additives is from 0.005 to 10 percent by mass,
based on the total mass of the composition.
[BEST MODE FOR CARRYING OUT THE INVENTION]
[0104] The present invention will be further described in more
detail with reference to the following examples and comparative
examples but are not limited thereto.
EXAMPLES 1 TO 8 AND COMPARATIVE EXAMPLES 1 to 8
[0105] There were prepared transmission lubricating oil
compositions (Examples 1 to 8) as shown in Tables 1-1 and 1-2 and
those for comparison (Comparative Examples 1 to 8) as shown in
Tables 2-1 and 2-2. Each of the compositions was evaluated by (1) a
duration test of anti-shudder properties and (2) a fatigue life
test described below. The results are also shown in Tables 1-1,
1-2, 2-1, and 2-2.
[0106] (1) Duration Test of Anti-Shudder Properties
[0107] On the basis of "Automatic transmission fluids-Anti-shudder
performance test" prescribed in JASO M349-98, the low velocity
sliding test wherein the fluid temperature during the duration test
was changed from 120.degree. C. to 140.degree. C. was conducted.
The duration of anti-shudder properties was evaluated with a ratio
of the duration of the reference oil used in the above test to that
of each of the compositions in Examples and Comparative
Examples.
[0108] The measurement was conducted for each composition every 24
hours after 0, 6, 12, and 24 hours.
[0109] If the duration of a composition was equal to or longer (72
hours or longer) than that of the reference oil, the composition
was judged to be excellent in duration of anti-shudder properties.
In the case where the duration was 4 times (288 hours) or longer
than that of the reference oil, the test was discontinued, the
evaluation was indicated by 4 or more.
[0110] (2) Fatigue Life Test
[0111] The fatigue life of each of the compositions was measured
using a two cylinder-type fatigue tester in the following
manner.
[0112] (Cylinder)
[0113] Material: SCM436
[0114] Shape: .PHI. 68 mm.times.10 mm
[0115] Hardness: SB3000 to 340
[0116] (Test Conditions)
[0117] Peripheral velocity: driving side: 12 m/s, driven side: 10
m/s
[0118] Oil temperature: 60.degree. C.
[0119] Surface pressure: 12 MPa
[0120] (Evaluation Criterion)
[0121] Time consumed until surface damages such as pitching appear
was evaluated as fatigue life. If the fatigue life of the
composition is 50 hours or longer, the composition was evaluated as
having a long fatigue life.
1 TABLE 1-1 Example 1 Example 2 Example 3 Example 4 (A) Base oil
Refined mineral oil (Base oil viscosity @100.degree. C. mass
%.sup.2) 100 100 100 100 4.0 mm.sup.2/s) Refined mineral oil (Base
oil viscosity @100.degree. C. mass %.sup.2) -- -- -- -- 2.6
mm.sup.2/s) Poly-.alpha.-olefin (Base oil viscosity @100.degree. C.
mass %.sup.2) -- -- -- -- 2.6 mm.sup.2/s).sup.1) Refined mineral
oil (Base oil viscosity @100.degree. C. mass %.sup.2) -- -- -- --
31 mm.sup.2/s) Adjusted base oil viscosity mm.sup.2/s 4 4 4 4 (B)
Calcium salicylate (BN = 170 mgKOH/g) mass % (Ca
concentration).sup.3) 0.007 0.03 0.06 0.03 (C) SP type extreme
Trilaulyltrithiophosphite mass % (P concentration).sup.3) 0.02 0.02
0.02 -- pressure additive Trilaulyldithiophosphite mass % (P
concentration).sup.3) -- -- -- 0.02 Di(2-ethylhexyl)
dithiophosphate mass % (P concentration).sup.3) -- -- -- --
Phosphorus-based additive Di(2-ethylhexyl) phosphite mass % (P
concentration).sup.3) 0.01 0.01 0.01 0.01 (D) Succinimide
Succinimide A.sup.4) mass %.sup.3) 2 2 2 2 Succinimide B.sup.5)
mass %.sup.3) -- -- -- -- (E) Ashless dispersant Boron-free ashless
dispersant.sup.6) 2 2 2 2 Boron-containing ashless
dispersant.sup.7) mass % (B concentration).sup.3) 0.005 0.005 0.005
0.005 Other additives.sup.8) mass %.sup.3) 8 8 8 8 (1) Fatigue life
hours 96 102 98 98 (2) Anti-shudder property durability ratio
between the composition and the reference oil (72 hours) 4<
4< 4< 4< .sup.1)prepared by mixing poly-.alpha.-olefin of
1.8 mm.sup.2/s @100.degree. C. and poly-.alpha.-olefin of 4
mm.sup.2/s @100.degree. C. .sup.2)based on the total mass of base
oil .sup.3)based on the total mass of composition
.sup.4)diethylenetriamine bis(iso-octadecenyl) succinimide
.sup.5)tetraethylenepentamine bis(iso-octadecenyl) succinimide
.sup.6)polybutenyl succinimide (bis type, weight-average molecular
weight of polybutenyl group: 1,000) .sup.7)boric acid-modified
polybutenyl succinimide (bis type, boron content: 0.5 mass %,
weight-average molecular weight of polybutenyl group: 1,300)
.sup.8)anti-oxidant (amine-based, phenol-based), seal swelling
agent (aroma-based), friction modifier (amine-based + ester-based),
viscosity index improver, and pour-point depressant
(polymethacrylate-based)
[0122]
2 TABLE 1-2 Example 5 Example 6 Example 7 Example 8 (A) Base oil
Refined mineral oil (Base oil viscosity @100.degree. C. mass
%.sup.2) 100 100 -- -- 4.0 mm.sup.2/s) Refined mineral oil (Base
oil viscosity @100.degree. C. mass %.sup.2) -- -- 75 -- 2.6
mm.sup.2/s) Poly-.alpha.-olefin (Base oil viscosity @100.degree. C.
2.6 mm.sup.2/s).sup.1) mass %.sup.2) -- -- -- 75 Refined mineral
oil (Base oil viscosity @100.degree. C. mass %.sup.2) -- -- 25 25
31 mm.sup.2/s) Adjusted base oil viscosity mm.sup.2/s 4 4 4 4 (B)
Calcium salicylate (BN = 170 mgKOH/g) mass % (Ca
concentration).sup.3) 0.03 0.03 0.03 0.03 (C) SP type extreme
Trilaulyltrithiophosphite mass % (P concentration).sup.3) -- 0.02
0.02 0.02 pressure additive Trilaulyldithiophosphite mass % (P
concentration).sup.3) -- -- -- -- Di(2-ethylhexyl) dithiophosphate
mass % (P concentration).sup.3) 0.02 -- -- -- Phosphorus-based
additive Di(2-ethylhexyl) phosphite mass % (P concentration).sup.3)
0.01 0.01 0.01 0.01 (D) Succinimide Succinimide A.sup.4) mass
%.sup.3) 2 -- 2 2 Succinimide B.sup.5) mass %.sup.3) -- 2 -- -- (E)
Ashless dispersant Boron-free ashless dispersant.sup.6) 2 2 2 2
Boron-containing ashless dispersant.sup.7) mass % (B
concentration).sup.3) 0.005 0.005 0.005 0.005 Other
additives.sup.8) mass %.sup.3) 8 8 8 8 (1) Fatigue life hours 102
108 120< 120< (2) Anti-shudder property durability ratio
between the composition and the reference oil (72 hours) 4<
4< 4< 4< .sup.1)prepared by mixing poly-.alpha.-olefin of
1.8 mm.sup.2/s @100.degree. C. and poly-.alpha.-olefin of 4
mm.sup.2/s @100.degree. C. .sup.2)based on the total mass of base
oil .sup.3)based on the total mass of composition
.sup.4)diethylenetriamine bis(iso-octadecenyl) succinimide
.sup.5)tetraethylenepentamine bis(iso-octadecenyl) succinimide
.sup.6)polybutenyl succinimide (bis type, weight-average molecular
weight of polybutenyl group: 1,000) .sup.7)boric acid-modified
polybutenyl succinimide (bis type, boron content: 0.5 mass %,
weight-average molecular weight of polybutenyl group: 1,300)
.sup.8)anti-oxidant (amine-based, phenol-based), seal swelling
agent (aroma-based), friction modifier (amine-based + ester-based),
viscosity index improver, and pour-point depressant
(polymethacrylate-based)
[0123]
3 TABLE 2-1 Com- Com- Com- Com- parative parative parative parative
Example 1 Example 2 Example 3 Example 4 (A) Base oil Refined
mineral oil (Base oil viscosity @100.degree. C. mass %.sup.1) 100
100 100 100 4.0 mm.sup.2/s) (B) Calcium salicylate (BN = 170
mgKOH/g) mass % (Ca concentration).sup.2) 0.09 -- 0.03 0.03 (C) SP
type extreme pressure additive Trilaulyltrithiophosphite mass % (P
concentration).sup.2) 0.02 0.02 0.1 -- Phosphorus-based additive
Di(2-ethylhexyl) phosphite mass % (P concentration).sup.2) 0.01
0.01 0.01 0.03 Sulfur-based additive Polyisobutylene sulfide (S
mass %.sup.2) -- -- -- -- content 45 mass %) Sulfated fat (Sulfated
lard, S mass %.sup.2) -- -- -- -- content 30 mass %) (D)
Succinimide Succinimide A.sup.3) mass %.sup.2) 2 2 2 2 (E) Ashless
dispersant Boron-free ashless mass %.sup.2) 2 2 2 2
dispersant.sup.4) Boron-containing ashless mass % (B
concentration).sup.2) 0.005 0.005 0.005 0.005 dispersant.sup.5)
Other additives.sup.6) mass %.sup.2) 8 8 8 8 (1) Fatigue life hours
52 18 26 32 (2) Anti-shudder property durability ratio between the
composition and the reference oil (72 hours) 0.33 0.67 0.33 4<
.sup.1)based on the total mass of base oil .sup.2)based on the
total mass of composition .sup.3)diethylenetriamine
bis(iso-octadecenyl) succinimide .sup.4)polybutenyl succinimide
(bis type, weight-average molecular weight of polybutenyl group:
1,000) .sup.5)boric acid-modified polybutenyl succinimide (bis
type, boron content: 0.5 mass %, weight-average molecular weight of
polybutenyl group: 1,300) .sup.6)anti-oxidant (amine-based,
phenol-based), seal swelling agent (aroma-based), friction modifier
(amine-based + ester-based), viscosity index improver, and
pour-point depressant (polymethacrylate-based)
[0124]
4 TABLE 2-2 Com- Com- Com- Com- parative parative parative parative
Example 5 Example 6 Example 7 Example 8 (A) Base oil Refined
mineral oil (Base oil viscosity @100.degree. C. mass %.sup.1) 100
100 100 100 4.0 mm.sup.2/s) (B) Calcium salicylate (BN = 170
mgKOH/g) mass % (Ca concentration).sup.2) 0.03 0.03 0.03 0.03 (C)
SP type extreme pressure additive Trilaulyltrithiophosphite mass %
(P concentration).sup.2) -- -- 0.03 0.03 Phosphorus-based additive
Di(2-ethylhexyl) phosphite mass % (P concentration).sup.2) 0.01
0.01 0.01 0.01 Sulfur-based additive Polyisobutylene sulfide (S
mass %.sup.2) 0.2 -- -- -- content 45 mass %) Sulfated fat
(Sulfated lard, S mass %.sup.2) -- 0.2 -- -- content 30 mass %) (D)
Succinimide Succinimide A.sup.3) mass %.sup.2) 2 2 -- 2 (E) Ashless
dispersant Boron-free ashless mass %.sup.2) 2 2 2 3
dispersant.sup.4) Boron-containing ashless mass % (B
concentration).sup.2) 0.005 0.005 0.005 -- dispersant.sup.5) Other
additives.sup.6) mass %.sup.2) 8 8 8 8 (1) Fatigue life hours
120< 120< 96 48 (2) Anti-shudder property durability ratio
between the composition and the reference oil (72 hours) 0.33 0.33
0.17 2 .sup.1)based on the total mass of base oil .sup.2)based on
the total mass of composition .sup.3)diethylenetriamine
bis(iso-octadecenyl) succinimide .sup.4)polybutenyl succinimide
(bis type, weight-average molecular weight of polybutenyl group:
1,000) .sup.5)boric acid-modified polybutenyl succinimide (bis
type, boron content: 0.5 mass %, weight-average molecular weight of
polybutenyl group: 1,300) .sup.6)anti-oxidant (amine-based,
phenol-based), seal swelling agent (aroma-based), friction modifier
(amine-based + ester-based), viscosity index improver, and
pour-point depressant (polymethacrylate-based)
[0125] As apparent from the results shown in Tables 1-1 and 1-2,
the lubricating oil compositions of Examples 1 to 8 had long
duration of both anti-shudder properties and anti-pitching
properties. As seen particularly from Examples 7 and 8 wherein a
heavy base oil with a high kinematic viscosity is blended, the
resulting lubricating oil compositions had further prolonged
duration of anti-pitching properties.
[0126] On the other hand, the composition containing too much
Component (B), i.e., calcium salicylate (Comparative Example 1) was
poor in duration of anti-shudder properties, and the composition
containing no Component (B) (Comparative Example 2) was poor in
duration of anti-pitching properties. The composition containing
too much Component (C), i.e., SP type extreme pressure additive
(Comparative Example 3) was satisfactory in duration of neither
anti-shudder properties nor anti-pitching properties. The
compositions containing no Component (C) (Comparative Examples 4 to
6) failed to achieve long-lasting anti-pitching properties and
anti-shudder properties at the same time. The composition
containing no Component (D), i.e., succinimide (Comparative Example
7) was poor in duration of anti-shudder properties, while the
composition containing no Component (E), i.e., boron-containing
ashless dispersant (Comparative Example 8) was poor in duration of
anti-pitching properties.
[0127] [Effects of the Invention]
[0128] The lubricating oil composition of the present invention has
excellent duration of anti-shudder properties and capable of
providing long fatigue life. Therefore, the lubricating oil
composition of the present invention can be used as a transmission
oil, particularly as a lubricating oil composition for automatic
transmissions and/or continuously variable transmission or
transmissions equipped with a wet clutch and/or wet brake as well
as a lubricating oil required to prevent pitching so as to improve
fatigue life, such as a gear oil, a lubricating oil for internal
combustion engines, a hydraulic oil for shock absorbers, and a
compressor oil.
* * * * *