U.S. patent application number 10/139378 was filed with the patent office on 2002-11-07 for lubricating oil composition for cellulose base wet friction material.
This patent application is currently assigned to Idemitsu Kosan Co., Ltd.. Invention is credited to Hata, Hitoshi, Machida, Hisashi.
Application Number | 20020165102 10/139378 |
Document ID | / |
Family ID | 15656369 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020165102 |
Kind Code |
A1 |
Hata, Hitoshi ; et
al. |
November 7, 2002 |
Lubricating oil composition for cellulose base wet friction
material
Abstract
There is disclosed a lubricating oil composition for cellulose
base wet friction material which comprises a base oil blended with
(A) a boron-containing imide base dispersant (e.g. boron treated
polyalkenyl succinimide) having a weight-average molecular weight
in the range of 500 to 3000 and having a ratio by weight of boron
to nitrogen (B/N) in the range of 0.1 to 1.5 in such a blending
amount that the boron content and the nitrogen content each derived
from the component (A) are made to be at least 60 ppm by weight and
at least 100 ppm by weight, respectively based on the base oil. The
above lubricating oil composition enhances peeling resistant
durability for a friction material, especially a cellulose base
friction material without impairing the wear resistance or scoring
resistance of a steel material element, and is well suited for use
in a cellulose base friction material for a starting and running
device and a transmission clutch that are used in an automatic
transmission of an automobile.
Inventors: |
Hata, Hitoshi;
(Ichihara-shi, JP) ; Machida, Hisashi;
(Fujisawa-shi, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
Idemitsu Kosan Co., Ltd.
Tokyo
JP
|
Family ID: |
15656369 |
Appl. No.: |
10/139378 |
Filed: |
May 7, 2002 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10139378 |
May 7, 2002 |
|
|
|
09585277 |
Jun 2, 2000 |
|
|
|
Current U.S.
Class: |
508/192 ;
508/429; 508/433; 508/434 |
Current CPC
Class: |
C10M 141/10 20130101;
C10M 2215/22 20130101; C10M 2215/086 20130101; C10M 2219/066
20130101; C10N 2040/044 20200501; C10M 2215/28 20130101; C10M
2219/068 20130101; C10M 135/18 20130101; C10M 2219/082 20130101;
C10M 2229/041 20130101; C10M 133/56 20130101; C10M 2215/26
20130101; C10M 135/04 20130101; C10M 2215/226 20130101; C10M
2223/10 20130101; C10M 2223/12 20130101; C10M 2207/024 20130101;
C10M 2223/042 20130101; C10M 2223/049 20130101; C10M 135/06
20130101; C10M 2219/085 20130101; C10M 2225/04 20130101; C10M
135/22 20130101; C10M 2217/06 20130101; C10M 2223/02 20130101; C10M
2227/061 20130101; C10M 2219/024 20130101; C10M 2219/083 20130101;
C10M 2219/084 20130101; C10M 135/24 20130101; C10M 2215/221
20130101; C10M 2219/022 20130101; C10M 2215/064 20130101; C10M
137/02 20130101; C10M 2223/04 20130101; C10M 2215/225 20130101;
C10M 2215/30 20130101; C10M 2215/04 20130101; C10M 2217/046
20130101; C10N 2040/046 20200501; C10N 2040/04 20130101; C10N
2040/042 20200501; C10M 2207/289 20130101 |
Class at
Publication: |
508/192 ;
508/429; 508/434; 508/433 |
International
Class: |
C10M 139/00; C10M
141/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 4, 1999 |
JP |
11-157742 |
Claims
What is claimed is:
1. A lubricating oil composition for cellulose base wet friction
material which comprises a base oil blended with (A) a
boron-containing imide base dispersant having a weight-average
molecular weight in the range of 500 to 3000 and having a ratio by
weight of boron to nitrogen (B/N) in the range of 0.1 to 1.5 in
such a blending amount that the boron content and the nitrogen
content each derived from the component (A) are made to be at least
60 ppm by weight and at least 100 ppm by weight, respectively based
on said base oil.
2. The lubricating oil composition according to claim 1, wherein
the boron-containing imide base dispersant as the component (A) has
a ratio by weight of boron to nitrogen (B/N) in the range of 0.2 to
1.0.
3. The lubricating oil composition according to claim 1, wherein
the boron-containing imide base dispersant as the component (A) is
produced by treating polyalkenyl succinimide with a boron
compound.
4. The lubricating oil composition according to claim 3, wherein
the polyalkenyl succinimide is polybutenyl succinimide.
5. The lubricating oil composition according to claim 1, wherein
the boron content derived from the component (A) is in the range of
60 to 300 ppm based on said base oil.
6. The lubricating oil composition according to claim 1, wherein
the nitrogen content derived from the component (A) is in the range
of 100 to 1200 ppm based on said bade oil.
7. The lubricating oil composition according to claim 1, which
further comprises (B) at least one member selected from the group
consisting of an active phosphorus base compound and an active
sulfur base compound.
8. The lubricating oil composition according to claim 7, wherein
the active phosphorus base compound is at least one member selected
from the group consisting of the acidic phosphate esters and
phosphite esters represented by the general formula (III): 6wherein
A is hydrogen atom or hydroxyl group; k is 0 or 1 with the proviso
that A is hydroxyl group when k is 0, and A is hydrogen atom or
hydroxyl group when k is 1; and R.sup.7 and R.sup.8 are each
hydrogen atom or a hydrocarbon group which has 1 to 18 carbon
atoms, and which may contain at least one member selected from the
group consisting of oxygen atom and sulfur atom with the proviso
that R.sup.7 and R.sup.8 may be the same as or different from each
other, but are not simultaneously hydrogen atom.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a lubricating oil
composition for a cellulose base wet friction material. More
particularly, the present invention is concerned with a lubricating
oil composition which enhances peeling resistant durability for a
friction material, especially a cellulose base wet friction
material without impairing the wear resistance or scoring
resistance of a steel material element, and which is well suited as
a lubricating oil composition for use in a cellulose base friction
material for a starting and running device and a transmission
clutch that are employed in an automatic transmission of an
automobile.
[0003] 2. Description of the Related Arts
[0004] It has become popular in recent years to employ as an
automobile transmission, a conventional automatic transmission, a
belt-drive continuously variable transmission, a traction drive
continuously variable transmission and the like.
[0005] Accompanying the aforesaid widened variety of automobile
transmissions, a transmission oil undergoes change in required
characteristics.
[0006] Said belt-drive continuously variable transmission and
traction drive continuously variable transmission are each equipped
with a starting/running device and a lock-up clutch, and besides
the belt-drive portion and traction drive portions each become a
new lubricating element. Accompanying the recent progress of
miniaturization, lightweightness and maximization of transmission
capacity, a lubricating oil is called upon to have lubricating
characteristics for lubricating portions of high surface pressure
such as gears, roller bearings, belt-drive portions and traction
drive portions in addition to the friction characteristics of a
friction material, for instance, to have wear resistance and
scoring (seizure) resistance therefor.
[0007] As mentioned before, a lubricating oil to be used in an
automobile transmission is called upon to be imparted with friction
characteristics for a friction material (wet clutch) and at the
same time, wear resistance and scoring (seizure) resistance, thus
bringing about a trend towards the use of an additive having high
reactivity with a metallic surface.
[0008] However, an additive having high reactivity with a metallic
surface, that is, an active additive is highly active also with
cellulose which is a principal component of a friction material.
Thus the aforesaid active additive suffers from such disadvantages
that brings about cutoff of cellulose structure (cutoff of
cellulose fibers in the form of rings and chains) and elution
thereof in oil or the like, and are more prone to cause damage such
as peeling to a friction material.
[0009] In such circumstances, there has eagerly been desired the
development of a lubrication technology capable of alleviating and
suppressing the attacking property (reactivity) for cellulose which
reaction is responsible for peeling and the like of a friction
material, without impairing the wear resistance and scoring
resistance thereof.
[0010] There has scarcely been any report on the technique for
alleviating and suppressing the peeling damage to a friction
material except the working effect of a metal base detergent
dispersant (calcium sulfonate having a total base number of 300)
{refer to preliminary prints for scientific lecture, Japan
Automotive Engineering Society, 952, 9535297, 1995-5}.
Nevertheless, in the case of blending the metal base detergent
dispersant, there is caused the problem of a fear of clogging the
pores on the surface of a friction material, thus deteriorating the
lubricating characteristics and the like.
SUMMARY OF THE INVENTION
[0011] Under such circumstances, a general object of the present
invention is to provide a lubricating oil composition which
enhances peeling resistant durability for a friction material,
especially a cellulose base wet friction material without impairing
the wear resistance or scoring resistance of a steel material
element, and which is well suited as a lubricating oil composition
for use in a cellulose base friction material for a starting and
running device and a transmission clutch that are employed in an
automatic transmission of an automobile.
[0012] Other objects of the present invention will be obvious from
the text of this specification hereinafter disclosed.
[0013] In view of the foregoing, intensive extensive research and
investigation were accumulated by the present inventors in order to
achieve the above-mentioned objects. As a result, it has been found
that the objects can effectively be attained by a lubricating oil
composition which comprises a base oil blended with a specific
boron-containing imide base dispersant so that the boron content
and the nitrogen content in the base oil are made to be at least a
prescribed value, respectively based on said base oil. The present
invention has been accomplished by the foregoing findings and
information.
[0014] Specifically, the present invention provides a lubricating
oil composition for a cellulose base wet friction material which
comprises a base oil blended with (A) a boron-containing imide base
dispersant having a weight-average molecular weight in the range of
500 to 3000 and a ratio by weight of boron to nitrogen (B/N) in the
range of 0.1 to 1.5 in such blending amounts that the boron content
and the nitrogen content each derived from the component (A) in the
base oil are made to be at least 60 ppm by weight and at least 100
ppm by weight, respectively based on said base oil.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The base oil to be used in the lubricating oil composition
according to the present invention is not specifically limited, but
may be properly and optionally selected for use from the base oils
which have heretofore been customarily used as a lubricating oil
composition in an automatic transmission of an automobile, and
which are exemplified by mineral oils and synthetic oil as
described hereunder.
[0016] Examples of the mineral oils include neutral oils that are
produced by solvent refining or hydrorefining such as 60 neutral
oil, 100 neutral oil, 150 neutral oil, 300 neutral oil and 500
neutral oil, and base oils having a low pour point and improved in
low temperature fluidity by removing wax component therefrom. Any
of the aforesaid mineral oils may be used alone or in combination
with at least one other species.
[0017] On the one hand, examples of the synthetic oils include
synthetic naphthene base oil, poly .alpha.-olefin oligomer and
ester base synthetic oils such as diester base, polyol ester base
and polyglycol ester base. Any of the aforesaid synthetic oils is
usually used alone, but may be used as a blend with the above
exemplified mineral oils.
[0018] In the present invention, the base oil is used usually in an
amount of at least 80% by weight based on the lubricating oil
composition.
[0019] In the lubricating oil composition according to the present
invention, there is used as the component(A), a boron-containing
imide base dispersant having a weight-average molecular weight in
the range of 500 to 3000 and a ratio by weight of boron to nitrogen
(B/N) in the range of 0.1 to 1.5. In the case where the
weight-average molecular weight departs from the aforesaid range,
or the ratio by weight of boron to nitrogen (B/N) deviates from
said range, it is made impossible to obtain the lubricating oil
composition imparted with the prescribed performances, thus failing
to achieve the objects of the present invention. In view of the
performances of the lubricating oil composition, the suitable
boron-containing imide base dispersant is that which has a
weight-average molecular weight in the range of 700 to 2500 and a
ratio by weight of boron to nitrogen (B/N) in the range of 0.2 to
1.0.
[0020] The aforesaid boron-containing imide base dispersant as the
component (A) is not specifically limited, provided that it is
imparted with the above-mentioned properties, and it may be
properly and optionally selected for use from among the additives
for a lubricating oil that have heretofore been customarily used
therefor. The foregoing boron-containing imide base dispersant is
exemplified by the compound obtained by treating, with a boron
compound, a monopolyalkenyl or polyalkyl succinimide represented by
the general formula (I): 1
[0021] or bispolyalkenyl or polyalkyl succinimide represented by
the general formula (II): 2
[0022] In the general formulae (I) and (II), R.sup.1, R.sup.3and
R.sup.4 are each independently an oligomer residue of an
.alpha.-olefin having approximately 2 to 8 carbon atoms or a
hydrate thereof, R.sup.3 and R.sup.4 may be the same or different,
R.sup.2, R.sup.5 and R.sup.6 are each independently an alkylene
group having 2 to 4 carbon atoms, R.sup.5 and R.sup.8 may be the
same or different, m is an integer from 1 to 10, and n is 0 or an
integer from 1 to 10.
[0023] In the present invention, the boron-containing imide base
dispersant as the component(A) may be any of the boron-treated
mono-compound represented by the general formula (I), the boron
treated bis-compound represented by the general formula (II) and a
mixture of the above two.
[0024] The aforesaid polyalkenyl or polyalkyl succinimide
represented by the general formula (I) or (II) can be produced
usually by allowing polyalkenyl succinimide anhydride which is
obtained by the reaction between a polyolefin and maleic anhydride
or the hydride thereof, namely polyalkyl succinimide anhydride to
react with a polyalkylene polyamine. The above-mentioned
mono-compound or bis-compound of the polyalkenyl or polyalkyl
succinimide can be produced usually by altering the reaction ratio
of the polyalkenyl or polyalkyl succinimide anhydride to the
polyalkylene polyamine.
[0025] The polyolefin which is used as a starting raw material in
the production of the aforesaid polyalkenyl or polyalkyl
succinimide, is properly and optionally selected for use from the
polyolefin which is obtained by polymerizing an .alpha.-olefin
having approximately 2 to 8 carbon atoms so that the boron
containing succinimide base dispersant as the final objective
product has a a weight-average molecular weight in the range of 500
to 3000. Moreover the .alpha.-olefin which constitutes the
polyolefin may be used alone or in combination with at least one
other species. As the polyolefin, polybutene is particularly
preferable.
[0026] On the one hand, the foregoing polyalkylene polyamine is
exemplified by polyethylene polyamine, polypropylene polyamine and
polybutylene polyamine, of which polyethylene polyamine is
preferable.
[0027] Of the aforesaid polyalkenyl or polyalkyl succinimide, there
is preferably usable polyalkenyl succinimide, especially
polybutenyl succinimide having a weight-average molecular weight of
approximately 500 to 3000.
[0028] In the lubricating oil composition according to the present
invention, it is necessary that the boron-containing imide base
dispersant as the components (A) be blended so that the boron
content and the nitrogen content that are derived from the
component (A) are made to be at least 60 ppm by weight and 100 ppm
by weight, respectively on the basis of the base oil. In the case
where the boron content is less than 60 ppm by weight or the
nitrogen content is less than 100 ppm by weight, it is made
impossible to alleviate or suppress the unfavorable attack by
active phosphate ester base compounds and active sulfur base
compound against the cellulose base friction material (acceleration
of cutoff and dissolution of cellulose chains due to the reaction
between the cellulose and the active phosphorus base compounds
and/or the active sulfur base compounds). Further, the friction
material is more liable to be early peeled or damaged on the
surface thereof. Taking into consideration the effective
suppression of damage to the surface of the friction material,
economical efficiency relating to the blending of the component,
the boron content is in the range of preferably 60 to 500 ppm by
weight, more preferably 60 to 300 ppm by weight and at the same
time, the nitrogen content is in the range of preferably 100 to
2000 ppm by weight, more preferably 100 to 1200 ppm by weight.
[0029] In the lubricating oil composition according to the present
invention, there is usually incorporated therein as the component
(B), at least one member selected from the group consisting of
active phosphorus base compounds and active sulfur base
compounds.
[0030] The above-mentioned active phosphorus base compound to be
used as the component (B) is not specifically limited, but may be
properly and optionally selected for use in accordance with the
situation from among the well known active phosphorus base
compounds that have heretofore been used as an extreme pressure
agent, an wear resistant agent, a friction modifying agent and the
like, for instance, acidic phosphate esters, phosphite esters,
acidic phosphite esters and hypophosphite esters.
[0031] As the active phosphate ester base compound to be used in
the lubricating oil composition according to the present invention,
there are preferably used the acidic phosphate esters and/or
phosphite esters represented by the general formula (III): 3
[0032] wherein A is hydrogen atom or hydroxyl group, k is 0 or 1
with the proviso that A is hydroxyl group when k is 0, and A is
hydrogen atom or hydroxyl group when k is 1, and R.sup.7 and
R.sup.8 are each hydrogen atom or a hydrocarbon group which has 1
to 18 carbon atoms and may contain at least one oxygen atom and/or
at least one sulfur atom.
[0033] Examples of the aforesaid hydrocarbon group which has 1 to
18 carbon atoms include a straight chain or branched alkyl group
having 1 to 18 carbon atoms; a cycloalkyl group having 3 to 18
carbon atoms; a straight chain or branched alkenyl group having 2
to 18 carbon atoms; an aryl group having 6 to 18 carbon atoms; and
an aralkyl group having 7 to 18 carbon atoms. Examples of the alkyl
group having 1 to 18 carbon atoms include methyl group, ethyl
group, n-propyl group, isopropyl group, n-butyl group, isobutyl
group, sec-butyl group, tert-butyl group, pentyl group, hexyl
group, octyl group, 2-ethyl-hexyl group, decyl group, dodecyl
group, tetradecyl group, hexadecyl group and, octadecyl group.
Examples of the cycloalkyl group having 3 to 18 carbon atoms group
include cyclopentyl group, cyclohexyl group, methylcyclohexyl group
and cyclooctyl group. Examples of alkenyl group having 2 to 18
carbon atoms include allyl group, propenyl group, butenyl group,
octenyl group, decenyl group and oleyl group. Examples of aryl
group having 6 to 18 carbon atoms include phenyl group, tolyl
group, xylyl group and naphthyl group. Examples of aralkyl group
having 7 to 18 carbon atoms include benzyl group, phenethyl group
and naphthylmethyl group.
[0034] In addition, the hydrocarbon group having 1 to 18 carbon
atoms may contain at-least one oxygen atom and/or at least one
sulfur atom. That is to say, the above-mentioned hydrocarbon group
may contain at least one ether group, or at least one thioether
group, or both said groups in its main chain. Examples of the
aforesaid hydrocarbon group include hexyloxymethyl group,
hexyloxyethyl group, octyloxymethyl group, octyloxyethyl group,
dodecyloxymethyl group, dodecyloxyethyl group, hexadecyloxymethyl
group, hexadecyloxyethyl group, hexylthiomethyl group,
hexylthioethyl group, octylthiomethyl group, octylthioethyl group,
dodecylthiomethyl group, dodecylthioethyl group,
hexadecylthiomethyl group and hexadecylthioethyl group.
[0035] The R.sup.7 and R.sup.8 may be the same as or different from
each other, but are not simultaneously hydrogen atom.
[0036] Examples of the acidic phosphate ester among the compound
represented by the general formula (III) include the compound
having the structure represented by the general formula (III-a)
4
[0037] wherein R.sup.7 and R.sup.8 are each as previously
defined.
[0038] Examples of the acidic phosphate ester represented by the
general formula (III-a) include mono- or di-hexylhydrogen
phosphate, mono- or di-octylhydrogen phosphate, mono- or
di-dodecylhydrogen phosphate, mono- or di-hexadecylhydrogen
phosphate, mono- or di-(hexylthioethyl)hydrogen phosphate, mono- or
di-(octylthioethyl)hydrogen phosphate, mono- or
di-(dodecylthioethyl)hydrogen phosphate, mono- or
di-(hexadecyl-thioethyl- )hydrogen phosphate, mono- or
di-octenylhydrogen phosphate, mono- or di-oleylhydrogen phosphate,
mono- or di-cyclohexylhydrogen phosphate, mono- or
di-phenylhydrogen phosphate, mono- or di-toluylhydrogen phosphate,
mono- or di-benzylhydrogen phosphate, mono- or di-phenetylhydrogen
phosphate and the like.
[0039] Examples of the phosphite ester among the compound
represented by the general formula (III) include the acidic
phosphite ester having the structure represented by the general
formula (III-b) or (III-c): 5
[0040] wherein R.sup.7 and R.sup.8 are each as previously
defined.
[0041] Examples of the acidic phosphite ester represented by the
general formula (III-b) or (III-c) include mono- or
di-hexyl-hydrogen phosphite, mono- or di-octylhydrogen phosphite,
mono- or di-dodecylhydrogen phosphite, mono- or
di-hexadecylhydrogen phosphate, mono- or
di-(hexylthioethyl)hydrogen phosphite, mono- or
di-(octylthioethyl)hydrog- en phosphite, mono- or
di-(dodecylthioethyl)hydrogen phosphite, mono- or
di-(hexadecyl-thioethyl)hydrogen phosphite, mono- or
di-octenylhydrogen phosphite, mono- or di-oleylhydrogen phosphite,
mono- or di-cyclohexylhydrogen phosphite, mono- or
di-phenylhydrogen phosphite, mono- or di-toluylhydrogen phosphite,
mono- or di-benzylhydrogen phosphite, mono- or di-phenetylhydrogen
phosphite and the like.
[0042] On the one hand, the above-mentioned active sulfur base
compound to be used as the component (B) is not specifically
limited, but may be properly and optionally selected for use from
among the well known active sulfur base compounds that have
heretofore been used as an extreme pressure agent, an anti-wear
agent, a friction modifier and the like, for instance, a sulfurized
fat and oil, that is, a sulfurized animal oil, vegetable oil or
synthetic oil; an olefin mono- or poly-sulfide; a dihydrocarbyl
mono- or poly-sulfide; a sulfurized mineral oil; a thiocarbamate;
thioterpene; and dialkylthiodipropionate.
[0043] Examples of the sulfurized fat and oil include sulfurized
lard, sulfurized rapeseed oil, sulfurized castor oil, sulfurized
soybean oil, sulfurized bran oil, disulfurized fatty acid such as
sulfurized oleic acid and sulfurized ester such as sulfurized
methyl oleate. Examples of the aforesaid olefin mono- or
poly-sulfide include a product which is produced by reacting an
olefin having 3 to 20 carbon atoms, preferably propylene, isobutene
or diisobutene or any of its dimer, trimer and tetramer with a
sulfurizing agent specifically exemplified by sulfur, sulfur
chloride and other sulfur halogenides.
[0044] The above-cited dihydrocarbyl mono- or poly-sulfide is a
compound represented by the general formula (IV):
R.sup.9-Sx-R.sup.10 (IV)
[0045] wherein R.sup.9 and R.sup.10 are each an alkyl group having
1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an
alkylaryl group having 7 to 20 carbon atoms, or an aralkyl group
having 7 to 20 carbon atoms, and may be the same as or different
from each other, and x is a real number from 1 to 8, more
specifically a rational number.
[0046] Specific examples of the R.sup.9 and R.sup.10 in the
foregoing general formula (IV) include methyl group, ethyl group,
n-propyl group, isopropyl group, n-butyl group, isobutyl group,
sec-butyl group, tert-butyl group, each pentyl group, each hexyl
group, each heptyl group, each octyl group, each nonyl group, each
decyl group, each dodecyl group, cyclohexyl group, cyclooctyl
group, phenyl group, naphthyl group, tolyl group, xylyl group,
benzyl group and phenethyl group.
[0047] The above-cited dihydrocarbyl mono- or poly-sulfide is
preferably exemplified by dibenzyl mono- or poly-sulfide,
di-tert-nonyl mono- or poly-sulfide and didodecyl mono- or
poly-sulfide.
[0048] Examples of the thiocarbamate are zinc dithiocarbamate,
etc., those of the thioterpene are a reaction product between
phosphorus pentasulfide and pinene, and the like, and those of the
dialkylthio-dipropionate are dilaurylthio-dipropionate,
distearylthio-dipropionate, and the like.
[0049] In the present invention, the active phosphorus base
compound or the active sulfur base compound as the component (B)
may be used alone or in combination with at least one other
species. The blending amount of the component (B) is not
specifically limited provided that said amount falls within the
scope of the amount usually employed in a transmission lubricating
oil for automobiles.
[0050] In the case where the active phosphorus base compound is
used as the component (B) in the present invention, the
above-mentioned boron-containing imide base dispersant as the
component (A) and the active phosphorus base compound as the
component (B) can be blended in the base oil after mixing in
advance both the components as desired, and then subjecting the
resultant mixture to heating treatment at a temperature in the
range of 120 to 150.degree. C. for at least 5 hours. It is
acceptable in this case to mix the component (A) in part and the
active phosphorus base compound as the component (B) in part that
are to be blended, subject the resultant mixture to heating
treatment, and subsequently mix into the base oil, the heated
mixture and the remainders of the component (A) and the component
(B). Alternatively, it is also acceptable in this case to mix the
component (A) in whole and the component (B) in whole that are to
be blended, subject the resultant mixture to heating treatment, and
subsequently mix the heated mixture into the base oil.
[0051] In more detail, the above-mentioned method for heating
treatment of both the components comprises the steps of mixing the
component (A) and the component (B) at a prescribed ratio,
agitating the resultant mixture at a temperature in the range of
approximately 40 to 70.degree. C. for approximately 10 minutes to 3
hours to carry out homogenization treatment, and subsequently
subjecting the resultant homogenizedly treated mixture to heating
treatment at a temperature in the range of 120 to 150.degree. C.
for at least 5 hours, preferably for 5 to 24 hours, wherein said
heating treatment may be put into practice under standing still or
under stirring.
[0052] The lubricating oil composition according to the present
invention may be properly and optionally incorporated at need with
any of other well known additives, which are exemplified by
antioxidants of phenol base, amine base and zinc dithiophosphate
base; detergents/dispersants of imide base, ester base, benzylamine
base, phenate base and salicylate base; friction modifiers of amide
base, ester base and fatty acid base;rust preventive agents of
metal sulfonate base, succinate ester base and sorbitan ester base;
metal deactivators of benzotriazole base and thiadiazole base; and
anti-foam agents of silicone base; and the like.
[0053] The lubricating oil composition according to the present
invention enhances peeling resistant durability for a friction
material, especially a cellulose base wet friction material without
impairing the wear resistance or scoring resistance of a steel
material element, and thus is well suited for use in a cellulose
base friction material for a starting and running device and a
transmission clutch that are employed in an automatic transmission
of an automobile.
[0054] In the following, the present invention will be described in
further detail with reference to comparative examples and working
examples, which however shall never limit the present invention
thereto.
[0055] The performances of the lubricating oil composition
according to the present invention were evaluated in accordance
with the procedures as described hereunder.
[0056] <weight loss of filter paper>
[0057] Filter paper immersion test was carried out by placing 75 ml
of a sample oil in a 100 ml wide mouthed vessel, immersing two
sheets of #51 B filter paper manufactured by ADVA NTEC Co. Ltd.
(measuring 20.times.80 mm, made of pure cellulose) in the sample
oil, covering the vessel with a lid made of aluminum foil, and
heating the vessel in a thermostat (air bath) at 175.degree. C. for
40 hours under standing still condition.
[0058] The filter paper was weighed before and after the test, and
the weight loss of the filter paper was calculated by the following
formula, in which the more the weight loss thereof, the severer the
attack to the cellulose as the filter paper material.
[0059] weight loss (%)={(weight before test-weight after
test)/weight before test}.times.100
[0060] In the following, some description will be given of the
various additives that were used in the above-mentioned tests.
Additive (1); boronated polybutenyl succinimide (manufactured by
Lubrizol Co., Ltd. under the trade name "Lz935") having a
weight-average molecular weight of 950, a B content of 1.98% by
weight, an N content of 2.05% by weight, a total acid number of 7.3
mg KOH/g, a base number of 65.8 mg KOH/g and a B/N ratio by weight
of 0.97
[0061] Additive (2); boronated polybutenyl succinimide
(manufactured by Exxon Chemical Co., Ltd. under the trade name "ECA
5025") having a weight-average molecular weight of 950, a B content
of 0.33% by weight, an N content of 1.35% by weight, a total acid
number of 6.5 mg KOH/g, a base number of 32.5 mg KOH/g and a B/N
ratio by weight of 0.24
[0062] Additive (3); boronated polybutenyl succinimide
(manufactured by Ethyl Japan Co., Ltd. under the trade name "EOA
8015") having a weight-average molecular weight of 950, a B content
of 1.15% by weight, an N content of 1.46% by weight, a total acid
number of 0.65 mg KOH/g, a base number of 45.2 mg KOH/g and a B/N
ratio by weight of 0.79
[0063] Additive (4); mono (2-ethylhexyl) hydrogenphosphate
(manufactured by Sakai Chemical Industry Co.,Ltd.) having a P
content of 12% by weight and a total acid number of 320 mg
KOH/g
[0064] Additive (5); phosphorus/sulfurized terpene (manufactured by
Ethyl Japan Co., Ltd.) having an S content of 13% by weight, a P
content of 4.8% by weight and a total acid number of 6.6 mg
KOH/g
[0065] Additive (6); polybutenyl succinimide (manufactured by
Lubrizol Co., Ltd. under the trade name "Lz6406") having an N
content of 1.76% by weight, a total acid number of 1.5 mg KOH/g and
a base number of 46.8 mg KOH/g
[0066] Additive (7); polybutenyl succinimide (manufactured by
Oronite Japan Ltd. under the trade name "OLOA 373") having an N
content of 1.05% by weight, a total acid number of 4.5 mg KOH/g and
a base number of 20.1 mg KOH/g
EXAMPLES 1 to 5 and COMPARATIAVE EXAMPLES 1 to 6
[0067] Various lubricating oil compositions were each prepared by
blending at least one of the additives 1 to 7, the blending amounts
of which are shown in Table 1 with a 150 neutral oil as a paraffin
base mineral oil (manufactured by Idemitsu Kosan Co., Ltd.) having
kinematic viscosity of 30.7 mm.sup.2/sec at 40.degree. C. and 5.25
mm.sup.2/sec at 100.degree. C. and a viscosity index of 104, and
further blending therewith, 0.5% by weight of 4, 4'-methylenebis(2,
6-di-tert-butylphenol) {manufactured by Ethyl Japan Co.,Ltd.}, 0.5%
by weight of 4, 4'-dioctylphenylamine {manufactured by Kawaguchi
Chemical Co., Ltd.}, 0.3% by weight of oleic acid monoglyceride
{manufactured by Kao Corporation}, 0.02% by weight of 1, 2,
3-benzotriazole {manufactured by Johoku Chemical Co., Ltd.} and
0.002% by weight of polydimethylsiloxane {manufactured by Shin-Etsu
Chemical Co., Ltd.} each based on the whole amount of the
lubricating oil composition in question. Thus, the above-described
tests were carried out, and evaluations were made of the
performances of each of the lubricating oil compositions thus
prepared.
[0068] The results of evaluating the performances of the various
lubricating oil compositions are given in Table 1.
1 TABLE 1-1 Example 1 2 3 4 5 Component (A) Additive 1 0.5 1.0 --
-- 0.5 (wt %) Additive 2 -- -- 2.0 -- -- Additive 3 -- -- -- 0.7 --
Component (B) Additive 4 0.2 0.2 0.2 0.2 -- (wt %) Additive 5 -- --
-- -- 1.0 Other compo- Additive 6 -- -- -- -- -- nent (wt %)
Additive 7 -- -- -- -- -- Boron content in oil 100 200 66 80 100
derived from component (A) in lubricating oil composition (wt ppm)
Nitrogen content in oil 103 205 270 102 103 derived from component
(A) or other components in lubricating oil composition (wt ppm)
Weight loss of filter 10.6 5.8 7.4 12.6 6.4 paper (wt %)
[0069]
2 TABLE 1-2 Comparative Example 1 2 3 4 5 6 Component (A) Additive
1 -- -- 0.3 -- -- -- (wt %) Additive 2 -- -- -- -- -- -- Additive 3
-- -- -- 0.5 -- -- Component (B) Additive 4 0.2 -- 0.2 0.2 0.2 0.2
(wt %) Additive 5 -- 1.0 -- -- -- -- Other compo- Additive 6 -- --
-- -- 2.0 -- nent (wt %) Additive 7 -- -- -- -- -- 2.0 Boron
content in oil 0 0 59 58 0 0 derived from component (A) in
lubricating oil composition (wt ppm) Nitrogen content in oil 0 0 62
73 350 210 derived from component (A) or other components in
lubricating oil composition (wt ppm) Weight loss of filter 45.6
24.6 29.5 24.7 17.8 28.6 paper (wt %)
* * * * *