U.S. patent application number 13/359945 was filed with the patent office on 2013-01-31 for lubricating oil composition and method for operating automatic transmission.
This patent application is currently assigned to Chevron Oronite Company LLC. The applicant listed for this patent is Masami Fuchi, Takahiro Nakagawa, Shrestha Kedar Shanker, Michio Shiga. Invention is credited to Masami Fuchi, Takahiro Nakagawa, Shrestha Kedar Shanker, Michio Shiga.
Application Number | 20130029890 13/359945 |
Document ID | / |
Family ID | 46839515 |
Filed Date | 2013-01-31 |
United States Patent
Application |
20130029890 |
Kind Code |
A1 |
Shanker; Shrestha Kedar ; et
al. |
January 31, 2013 |
Lubricating Oil Composition and Method for Operating Automatic
Transmission
Abstract
A lubricating oil composition containing a bis-type
alkenyl-substituted succinimide which is prepared by reaction of
succinic anhydride substituted with 2-alkenyl group having a
branched structure in .beta.-position with alkylenepolyamine or a
compound derived from the bis-type alkenyl-substituted succinimide
by post-treatment in combination with a mixture of an overbased
sulfonate having a C.sub.20-C.sub.24 alkyl group and an overbased
salicylate having a C.sub.14-C.sub.18 alkyl group shows a high
friction coefficient within a wide sliding velocity range and keeps
its high anti-shudder performance for a long period of time.
Inventors: |
Shanker; Shrestha Kedar;
(Kakegawa, JP) ; Shiga; Michio; (Hiratsuka,
JP) ; Fuchi; Masami; (Makinohara, JP) ;
Nakagawa; Takahiro; (Haibara, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shanker; Shrestha Kedar
Shiga; Michio
Fuchi; Masami
Nakagawa; Takahiro |
Kakegawa
Hiratsuka
Makinohara
Haibara |
|
JP
JP
JP
JP |
|
|
Assignee: |
Chevron Oronite Company LLC
San Ramon
CA
|
Family ID: |
46839515 |
Appl. No.: |
13/359945 |
Filed: |
January 27, 2012 |
Current U.S.
Class: |
508/192 |
Current CPC
Class: |
C10M 2215/223 20130101;
C10M 2207/262 20130101; C10N 2060/14 20130101; C10N 2030/06
20130101; C10N 2040/044 20200501; C10M 2215/08 20130101; C10M
2203/1025 20130101; C10M 2209/084 20130101; C10M 163/00 20130101;
C10M 2219/106 20130101; C10M 2219/044 20130101; C10M 2215/064
20130101; C10M 2219/046 20130101; C10N 2040/045 20200501; C10M
2207/026 20130101; C10M 2215/28 20130101; C10M 2229/02 20130101;
C10M 2223/049 20130101; C10N 2060/12 20130101; C10N 2030/76
20200501 |
Class at
Publication: |
508/192 |
International
Class: |
C10M 169/04 20060101
C10M169/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 2, 2011 |
JP |
JP2011-021118 |
Claims
1. A lubricating oil composition comprising a base oil having a
lubricating viscosity and the following additives: a friction
modifier in an amount of 0.1 to 10 wt. %, a nitrogen-containing
ashless dispersant in an amount of 0.05 to 10 wt. %, a phosphorus
compound in an amount of 0.1 to 10 wt. %, and a metal-containing
detergent in an amount of 0.005 to 4 wt. %, in which the amounts of
the additives are based on an amount of the lubricating oil
composition, the friction modifier is selected from the group
consisting of: a friction modifier (A) comprising an
alkenyl-substituted succinimide of the following formula (1) or a
post-treated derivative thereof: ##STR00006## in which each of
R.sub.1 and R.sub.1' independently is an alkenyl group having a
branched structure in .beta.-position which is represented by the
following formula (1), R.sub.2 is a hydrogen atom, an alkyl group
having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon
atoms, an aralkyl group having 7 to 13 carbon atoms, or a 5-8
membered heterocyclic group, x is an integer of 1 to 6, and y is an
integer of 0 to 20: ##STR00007## in which each of R.sub.3 and
R.sub.4 is an aliphatic hydrocarbyl group and a total carbon atom
number of R.sub.3 an R.sub.4 is in the range of 3 to 45, under the
condition that a carbon atom number of R.sub.3 is larger than a
carbon atom number of R.sub.4 by 3 or a carbon atom number of
R.sub.3 is smaller than a carbon atom number of R.sub.4 by 1; and,
a friction modifier (B) which comprises an alkenyl-substituted
succinimide of the following formula (II) or a post-treated
derivative thereof: ##STR00008## in which each of R.sub.1 and
R.sub.1' independently is an alkenyl group having a branched
structure in .beta.-position which is derived from a dimer of a
single linear .alpha.-olefin having 3 to 24 carbon atoms, and Q is
a residue of an alkylene-polyamine having a 1 to 20 carbon atoms
and containing an amino group at least at each terminal thereof,
and said metal-containing detergent is a mixture of an overbased
sulfonate having an alkyl group containing 20-24 carbon atoms and
an overbased salicylate having an alkyl group containing 14-18
carbon atoms in a weight ratio of 1:4 to 4:1.
2. The lubricating oil composition of claim 1, in which the
friction modifier is the friction modifier (A) in which each of
R.sub.3 and R.sub.4 in the formula (1) independently is a linear
alkyl group and the total carbon atom number contained in R.sub.3
and R.sub.4 is in the range of 13 to 21.
3. The lubricating oil composition of claim 1, in which x is 2 and
y is an integer of 1 to 3.
4. The lubricating oil composition of claim 1, in which x is 2 and
y is 1.
5. The lubricating oil composition of claim 1, in which the
post-treated derivative is an alkenyl-substituted succinimide of
formula (1) which is post-treated with boric acid, phosphoric acid,
a carboxylic acid, or ethylene carbonate.
6. The lubricating oil composition of claim 1, in which the
friction modifier is the friction modifier (B) wherein the dimer is
prepared by dimerization of a linear .alpha.-olefin having 8 to 12
carbon atoms.
7. The lubricating oil composition of claim 1, in which the
friction modifier is the friction modifier (B) wherein the dimer is
2-hexyl-1-decene, 2-octyl-1-dodecene or 2-decyl-1-tetradecene.
8. The lubricating oil composition of claim 1, in which the
friction modifier is the friction modifier (B) wherein the dimer is
2-octyl-1-dodecene.
9. The lubricating oil composition of claim 1, in which the
friction modifier is the friction modifier (B) wherein the
alkylene-polyamine is ethylenediamine, diethylenetriamine or
triethylenetetramine.
10. The lubricating oil composition of claim 1, in which the
friction modifier is the friction modifier (B) wherein the
alkylene-polyamine is diethylenetriamine.
11. The lubricating oil composition of claim 1, in which the
friction modifier is the friction modifier (B) wherein the
post-treated derivative is the alkenyl-substituted succinimide of
formula (II) which is post-treated with boric acid, phosphoric
acid, a carboxylic acid or ethylene carbonate.
12. The lubricating oil composition of claim 1, in which the
overbased sulfonate has a TBN in the range of 120 to 400 mg KOH/g
and the overbased salicylate has a TBN in the range of 60 to 330 mg
KOH/g.
13. The lubricating oil composition of claim 1, which is a
lubricating oil for automatic transmissions.
14. The lubricating oil composition of claim 13, in which the
automatic transmissions are selected from the group consisting of
automatic transmissions, continuously variable transmissions and
dual clutch transmissions.
15. A method for operating an automatic transmission in the
presence of the lubricating oil composition of claim 1.
16. The method of claim 15, in which the automatic transmission is
selected from the group consisting of automatic transmissions,
continuously variable transmissions and dual clutch transmissions.
Description
[0001] This application claims priority to Japanese Patent
Application number JP2011-021118 which was filed in Japan on
2-2-2011.
FIELD OF INVENTION
[0002] The present invention relates to a lubricating oil
composition that shows a high friction coefficient in a wide
sliding velocity range and keeps good anti-shudder performance for
a long time of period. In particular, the invention relates to a
lubricating oil composition valuable as a lubricating oil for
automatic transmissions. The invention further relates to a method
for operating an automatic transmission using the lubricating oil
composition.
BACKGROUND OF INVENTION
[0003] Heretofore, an automatic transmission oil, that is, a
lubricating oil for automatic transmissions, has been employed for
assisting smooth operation of automatic transmissions equipped with
a torque converter, gear mechanism, wet clutch and hydraulic
system, such as automatic transmissions, continuously variable
transmissions and dual clutch transmissions. For the recently
developed automobiles, it is required to improve fuel economy.
Therefore, the recently developed automobiles have been
manufactured to have a less volume and a less weight. The automatic
transmissions are also required to have a less volume and a less
weight for the improvement of fuel economy. Thus developed small
sized and light weight automatic transmissions require a
lubricating oil showing improved friction performance such as
higher friction coefficient. In addition, since automobiles
equipped with an automatic transmission sometimes encounter
vibration (that is referred to as "shudder") when the automatic
transmission operates, the lubricating oil is required to keep the
shudder caused in the operation of the automatic transmission under
a lower level for a sufficiently long period of time.
[0004] WO 97/14773 A1 discloses a lubricating fluid for power
transmissions which contains an additive comprising an
alkenyl-substituted succinimide that is prepared by reaction of a
succinic anhydride substituted with an alkenyl group having a
branch structure in a-position and polyamine. It is described that
the addition of the additive enables to maintain good anti-shudder
performance for a long period of time.
[0005] WO 97/14772 A1 discloses a lubricating oil composition
containing an alkenyl-substituted succinimide that is prepared by
reaction of a succinic anhydride substituted with an alkenyl group
having a branch structure in a-position and an amine compound.
[0006] WO 2008/157467 A2 discloses novel pyrrolidine compounds and
succinimide compound which are of value as friction modifiers for
imparting excellent friction modifying performance to lubricating
oil compositions without adverse effects on the viscosity
properties of the lubricating oil composition at low
temperatures.
[0007] Tribology online, 3, 6(2008), pp. 328-332 discloses results
of studies of low molecular weight alkenylsuccinimides on
anti-shudder performance. In the study, a number of low molecular
weight alkenylsuccinimides and aliphatic amide compounds are
tested. Examples of the low molecular weight alkenylsuccinimides
include a bis-type alkenyl-substituted succinimide obtained by
reaction of succinic anhydride which is substituted with
2-pentyl-2-tridecyl and an amine compound as well as a bis-type
alkenyl-substituted succinimide obtained by reaction of succinic
anhydride which is substituted with 2-hexyl-2-hexadecenyl and an
amine compound.
SUMMARY OF INVENTION
[0008] One embodiment of the present invention is to provide a
lubricating oil composition containing a novel friction modifier
which is capable of imparting excellent friction modifying
performances to the lubricating oil composition.
[0009] Another embodiment of the present invention is to provide a
method for operating automatic transmissions using the lubricating
oil composition.
[0010] In one aspect, the present invention provides a lubricating
oil composition comprising a base oil having a lubricating
viscosity and the following additives:
[0011] a friction modifier in an amount of 0.1 to 10 wt. %, a
nitrogen-containing ashless dispersant in an amount of 0.05 to 10
wt. %,
[0012] a phosphorus compound in an amount of 0.1 to 10 wt. %,
and
[0013] a metal-containing detergent in an amount of 0.005 to 4 wt.
%,
[0014] in which the amounts of the additives are based on an amount
of the lubricating oil composition,
[0015] the friction modifier is selected from the group consisting
of
[0016] a friction modifier (A) comprising an alkenyl-substituted
succinimide of the following formula (I) or a post-treated
derivative thereof:
##STR00001##
in which each of R.sub.1 and R.sub.1' independently is an alkenyl
group having a branched structure in .beta.-position which is
represented by the following formula (1), R.sub.2 is a hydrogen
atom, an alkyl group having 1 to 12 carbon atoms, an aryl group
having 6 to 12 carbon atoms, an aralkyl group having 7 to 13 carbon
atoms, or a 5-8 membered heterocyclic group, x is an integer of 1
to 6, and y is an integer of 0 to 20:
##STR00002##
in which each of R.sub.3 and R.sub.4 is an aliphatic hydrocarbyl
group and a total carbon atom number of R.sub.3 an R.sub.4 is in
the range of 3 to 45, under the condition that a carbon atom number
of R.sub.3 is larger than a carbon atom number of R.sub.4 by 3 or a
carbon atom number of R.sub.3 is smaller than a carbon atom number
of R.sub.4 by 1; and,
[0017] a friction modifier (B) which comprises an
alkenyl-substituted succinimide of the following formula (11) or a
post-treated derivative thereof:
##STR00003##
in which each of R.sub.1 and R.sub.1' independently is an alkenyl
group having a branched structure in .beta.-position which is
derived from a dimer of a single linear .alpha.-olefin having 3 to
24 carbon atoms, and Q is a residue of an alkylene-polyamine having
a 1 to 20 carbon atoms and containing an amino group at least at
each terminal thereof, and
[0018] said metal-containing detergent is a mixture of an overbased
sulfonate having an alkyl group containing 20-24 carbon atoms and
an overbased salicylate having an alkyl group containing 14-18
carbon atoms in a weight ratio of 1:4 to 4:1.
[0019] The lubricating oil composition can contain the friction
modifier (A) and friction modifier (B) in combination.
[0020] From another point, the present invention provides a method
for operating automatic transmissions (specifically, automatic
transmissions, continuously variable transmissions, and dual clutch
transmissions) in the presence of the above-mentioned lubricating
oil composition.
[0021] The lubricating oil composition provided by the invention is
effective to impart improved friction performances such as an
increased friction coefficient and a prolonged friction coefficient
stability. Therefore, a lubricating oil composition containing the
friction modifier of the invention can keep shuddering of an
automatic transmission under a satisfactorily low level for a
relatively long period of time.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Preferred embodiments of the lubricating oil composition of
the invention are described below.
[0023] (1) The friction modifier is the friction modifier (A), each
of R.sub.3 and R.sub.4 in the formula (1) independently is a linear
alkyl group, and the total carbon atom number contained in R.sub.3
and R.sub.4 is in the range of 13 to 21.
[0024] (2) In the formula (1), x is 2 and y is an integer of 1 to
3.
[0025] (3) In the formula (1), x is 2 and y is 1.
[0026] (4) The post-treated derivative is an alkenyl-substituted
succinimide of formula (I) which is post-treated with boric acid,
phosphoric acid, a carboxylic acid, or ethylene carbonate.
[0027] (5) The friction modifier is the friction modifier (B) and
the dimer is prepared by dimerization of a linear .alpha.-olefin
having 8 to 12 carbon atoms.
[0028] (6) The friction modifier is the friction modifier (B) and
the dimer is 2-hexyl-1-decene, 2-octyl-1-dodecene or
2-decyl-1-tetradecene.
[0029] (7) The friction modifier is the friction modifier (B) and
the dimer is 2-octyl-1-dodecene.
[0030] (8) The friction modifier is the friction modifier (B) and
the alkylene-polyamine is ethylenediamine, diethylenetriamine or
triethylenetetramine.
[0031] (9) The friction modifier is the friction modifier (B) and
the alkylene-polyamine is diethylenetriamine. (10) The friction
modifier is the friction modifier (B) and the post-treated
derivative is the alkenyl-substituted succinimide of formula (II)
which is post-treated with boric acid, phosphoric acid, a
carboxylic acid or ethylene carbonate.
[0032] (11) The overbased sulfonate has a TBN in the range of 120
to 400 mg KOH/g (particularly, 260 to 400 mg KOH/g), and the
overbased salicylate has a TBN in the range of 60 to 330 mg KOH/g
(particularly, 150 to 250 mg KOH/g).
[0033] (12). The lubricating oil composition is for automatic
transmissions.
[0034] (13) The lubricating oil composition is for automatic
transmissions such as automatic transmissions, continuously
variable transmissions, and dual clutch transmissions.
[0035] (14) The lubricating oil composition contains the friction
modifier in an amount of 0.5 to 5 wt. % (preferably 1 to 4 wt. %,
more preferably 1.5 to 3 wt. %) per the amount of the lubricating
oil composition.
[0036] (15) The nitrogen-containing ashless dispersant contained in
the lubricating oil composition is polyisobutenylsuccinimide or its
post-treated compound.
[0037] (16) The post-treated compound is a borated
polyisobutenylsuccinimide.
[0038] (17) The phosphorus compound contained in the lubricating
oil composition is phosphoric acid, a phosphoric acid ester,
phosphorous acid, a phosphorous acid ester, thiophosphoric acid, or
a thiophosphoric acid ester.
[0039] (18) The lubricating oil composition contains an
anti-oxidation agent.
[0040] (19) The lubricating oil composition contains a corrosion
inhibitor.
[0041] (20) The lubricating oil composition contains a viscosity
index improver.
[0042] (21) The base oil of the lubricating oil composition
contains a saturated component in an amount of at least 90 wt. %, a
viscosity index of 120 or more, and a sulfur content of 0.03 wt. %
or less.
[0043] The friction modifier of the invention as well as the base
oil and various additives comprised in the lubricating oil
composition are described in more detail.
Friction Modifier
[0044] The friction modifier of the invention is an
alkenyl-substituted succinimide represented by the aforementioned
formula (1) or ((1) or its post-treated compound.
[0045] The alkenyl-substituted succinimide of the formula (1) can
be prepared by reacting succinic anhydride substituted with a
2-alkenyl group having a branched structure in the the
.beta.-position with a polyamine.
[0046] The succinic anhydride substituted with a 2-alkenyl group
having a branched structure in the .beta.-position can be prepared
by the reaction between succinic anhydride with an alkene compound
having a vinylidene group at its terminal. The alkene compound
having a vinylidene group at its terminal can be represented by the
following formula (2):
##STR00004##
[0047] In the formula (2), each of R.sub.5 and R.sub.6 is an
aliphatic hydrocarbyl group (preferably a linear or branched alkyl
group, more preferably a linear alkyl group) under such condition
that a carbon atom number of R.sub.5 is larger than a carbon atom
number of R.sub.6 by 3 or a carbon atom number of R.sub.5 is
smaller than a carbon atom number of R.sub.6 by 1.
[0048] Examples of the alkene compound having a vinylidene group at
its terminal include 2-hexyl-1-decene, 2-octyl-1-dodecene and
2-decyl-1-tetradecene. Each of these alkene compounds can be
prepared by dimerizing 1-octene, 1-decene and 1-dodecene,
respectively.
[0049] The above-mentioned alkene compounds having a vinylidene
group at its terminal and their preparing methods are described in
JP2006-225348 A and JP2006-232672 A.
[0050] Examples of the polyamines employable for the preparation of
the alkenyl-substituted alkenylsuccinimide of the invention include
ethylenediamine, diethylenetriamine and triethylenetetramine. Most
preferred is diethylenetriamine.
[0051] The reaction between the succinic anhydride substituted with
a 2-alkenyl group having a branched structure in the
.beta.-position and polyamine can be performed in the manner
similar to the known manner for the reaction between succinic
anhydride and polyamine.
[0052] The friction Modifier employed for the lubricating oil
composition of the invention can be an alkenyl-substituted
succinimide represented by the aforementioned formula (I) or (II)
per se. Otherwise, the friction modifier can be a post-treated
alkenyl-substituted succinimide which is obtained by post-treatment
of the alkenyl-substituted succinimide with a known post-treating
agent such as borate, phosphate, carboxylate or ethylene
carbonate.
[0053] It should be noted that the reaction between the succinic
anhydride substituted with a 2-alkenyl group having a branched
structure in the .beta.-position and polyamine may give a
relatively small amount of a mono-type alkenyl-substituted
succinimide of the following formula (III) in addition of the
bis-type alkenyl-substituted succinimide of the formula (I) or
(II):
##STR00005##
[0054] In the formula (III), each of R.sub.1, R.sub.2, x and y has
the aforementioned meaning, and each of R.sub.3 and R.sub.4
independently represents a hydrogen atom, an alkyl group having
1-12 carbon atoms, an aryl group having 6-12 carbon atoms, an
aralkyl group having 7-13 carbon atoms, or a 5-8 membered
heterocyclic group.
[0055] Therefore, the friction modifier of the invention may
contain a small amount (20 wt. % or less) of the monotype
alkenyl-substituted succinimide of the formula (III) in addition to
the bis-type alkenyl-substituted succinimide of the formula (I) or
(II).
Base Oil
[0056] There are no specific limitations with respect to the base
oil to be employed for the preparation of the lubricating oil
composition of the invention. For instance, base oils having
various physical properties, for instance, base oils which are
known for the conventional transmission oils or conventional engine
oils for engines (particularly gasoline engines) of automobiles.
Examples of the base oil include mineral oils belonging to Groups 1
to 3, synthetic oils belonging to Group 4, and other oils belonging
to Group 5, which are described in API 1509. Preferred are mineral
oils and synthetic oils containing a saturated component in an
amount of at least 85 wt. % (more preferably, at least 90 wt. %) ,
a viscosity index of 100 or more (more preferably 120 or more), and
a sulfur content of 0.03 wt. % or less (more preferably 0.001 wt. %
or less).
[0057] The mineral-type base oil is preferably obtained by treating
a distillate having a lubricating viscosity with known methods such
as solvent refining and hydrogenation. Preferred are
hyper-hydrogenated oil (i.e., hydrocracked oil which typically has
a viscosity index of 120 or more, an evaporation loss (according to
ASTM D5800) of 15 wt. % or less, a sulfur content of 0.001 wt. % or
loss, and an aromatic content of 10 wt. % or less). A mixture of
oils containing 10 wt. % or more of the hydrocracked oil is also
employable. The hydrocracked oil can be an oil having a high
viscosity index (e.g., a viscosity index of 140 or more,
specifically a viscosity index in the range of 140 to 150) which is
produced by isomerization or hydrocracking of a mineral type slack
or natural gas, namely, gas-to-liquid (GTL) wax. The hydrocracked
oil is preferably employable as a base oil of the lubrication oil
composition of the invention due to its low sulfur content, low
evaporating property and low carbonaceous residue.
[0058] The synthetic oil (synthetic lubricating base oil) can be
poly-.alpha.-olefins produced by polymerization of .alpha.-olefin
having 3 to 12 carbon atoms, dialkyl diesters prepared by
esterification of di-basic acids (e.g., sebacic acid, azelaic acid,
and adipic acid) with an alcohol having 4-18 carbon atoms, such as
dioctyl sebacate, polyol esters prepared by esterification of
mono-basic acids having 3 to 18 carbon atoms with
1-trimethylolpropane or pentaerythritol, or alkylbenzenes having an
alkyl group of 9-14 carbon atoms. The synthetic oil is preferred as
a base oil of the lubricating oil composition of the invention
because not only it generally contains no sulfur-containing
components but also it shows good oxidation resistance and good
thermal resistance. Further, the synthetic oil gives less
carbonaceous residues and less soots when it is burnt. Most
preferred is poly-.alpha.-olefin.
[0059] The mineral base oil and synthetic base oil can be used
singly or in combination such as combinations of two or more
mineral base oils, combinations of two or more synthetic base oils,
and combinations of mineral base oils and synthetic base oils in
optional ratios.
Nitrogen-Containing Ashless Dispersant
[0060] Representative examples of the nitrogen-containing ashless
dispersants employable for the preparation of the lubricating oil
composition of the invention include alkenyl- or alkyl-succinimide
of which alkenyl group or alkyl group is derived from polyolefin
and its derivatives. A representative alkenyl- or alkyl-succinimide
can be obtained by the reaction of succinic anhydride substituted
with an alkenyl or alkyl group having a high molecular weight with
a polyalkylene polyamine having 3-10 (preferably 4-7) nitrogen
atoms per mole. The alkenyl or alkyl group having a high molecular
weight preferably is polyolefin having an average molecular weight
of approx. 900 to 5,000. Most preferred is polybutene.
[0061] In the process for preparing polybutenylsuccinic anhydride
by the reaction of polybutene and maleic anhydride, the
chlorination method employing chlorine can be employed. However,
although the chlorination method gives the succinimide in a good
yield, it generally results in the production of the succinimide
containing a relatively large chlorine content (e.g., approx. 2,000
ppm). In contrast, the thermal method employing no chlorine can
yields the succinimide containing an extremely small chlorine
content (e.g., approx. 40 ppm or less). In addition, if a highly
reactive polybutene (containing a methylvinylidene structure of
approx. 50% or more) is employed in the thermal method in place of
the conventional polybutene (mainly having .beta.-olefinic
structure), the reactivity of the thermal method increases. The
increase of the reactivity is advantageous results in reduction of
unreacted polybutene in the produced dispersant which favorably has
an active component (succinimide) of an high concentration.
Therefore, it is preferred that the polybutenylsuccinic anhydride
is obtained by employing the high reactive polybutene in the
thermal method, and that the resulting polybutenylsuccinic
anhydride is reacted with a polyalkylene polyamine having an
average nitrogen atoms of 3 to 10 (per one mole) to give a
succinimide. The succinimide can be further reacted (or treated)
with borate, an alcohol, an aldehyde, a ketone, an alkylphenol, a
cyclic carbonate, or an organic acid to give a modified
succinimide. Particularly, borated alkenyl(or alkyl)succinimide is
preferred because of its high thermal and oxidation resistance.
[0062] The succinimide can be of a mono-type, a bis-type or a
poly-type, which corresponds to number of the imide structure in
one molecule. In the lubricating oil composition of the invention,
succinimides of bis-type and poly-type are preferably employed.
[0063] The nitrogen-containing ashless dispersant can be a
polymer-containing succinimide which is prepared using an
ethylene-.alpha.-olefin copolymer having a molecular weight in the
range of 1,000 to 15,000, and an ashless dispersant of
alkenylbenzylamine type.
Metal-Containing Detergent
[0064] The metal-containing detergent used in the lubricating oil
composition of the invention preferably is a mixture of an
overbased sulfonate having an alkyl group containing 20-24 carbon
atoms and an overbased salicylate having an alkyl group containing
14-18 carbon atoms in a weight ratio of 1:4 to 4:1. The overbased
sulfonate preferably has a TBN (Total Base Number) in the range of
120 to 400 mg KOH/g (more preferably, 260 to 400 mg KOH/g), and the
over based salicylate preferably has a TBN in the range of 60 to
330 mg KOH/g (more preferably, 150 to 250 mg KOH/g).
[0065] The lubricating oil composition may further contain other
metal-containing detergents such as over-based phenates and/or
alkylcarboxylate having a variety of total base numbers, under such
conditions that the total amount of other metal-containing
detergents is less than the amount of the above-mentioned mixture
of the sulfonate and salicylate.
Phosphorus Compound
[0066] The phosphorus compounds can be those which are known as
anti-wear agents employable in the lubricating oil compositions.
Examples of the phosphorus compound include phosphoric acid, a
phosphoric acid ester, phosphorous acid, a phosphorous acid ester,
thiophosphoric acid and a thiophosphoric acid ester. Also
employable are amine salts of the phosphoric acid ester and
phosphorous acid ester.
Oxidation Inhibitor
[0067] The lubricating oil composition of the invention can contain
an oxidation inhibitor. The oxidation inhibitor preferably is a
known inhibitor such as a phenolic oxidation inhibitor or an amine
oxidation inhibitor. The oxidation inhibitor may be contained in
the lubricating oil composition in an amount of 0.1 to 5 wt. %,
preferably 0.5 to 3 wt. %.
[0068] The phenolic oxidation inhibitor can be a hindered phenol
compound. The amine oxidation inhibitor can be a diarylamine
compound.
[0069] Examples of the hindered phenol oxidation inhibitor include
2,6-di-t-butyl-p-cresol, 4,4'-methylenebis(2,6-di-t-butylphenol),
4,4'-methylenebis(6-t-butyl-o-cresol),
4,4'-isopropylidenebis(2,6-di-t-butylphenol),
4,4'-bis(2,6-di-t-butylphenol),
2,2'-methylenebis(4-methyl-6-t-butylphenol),
4,4'-thiobis(2-methyl-6-t-butylphenol),
2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
octyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, octadecyl
3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and octyl
3-(5-t-butyl-4-hydroxy-3-methylphenyl)propionate.
[0070] Examples of the diarylamine oxidation inhibitor include a
mixed alkyldiphenylamine having 4 to 9 carbon atoms,
p,p'-dioctyldiphenylamine, phenyl-.alpha.-naphthylamine,
phenyl-.beta.-naphthylamine, alkylated .alpha.-naphthylamine and
alkylated phenyl-.alpha.-naphthylamine.
[0071] The hindered phenol oxidation inhibitor and diarylamine
oxidation inhibitor can be employed singly or in combination. If
desired, other oil-soluble oxidation inhibitors can be employed in
combination.
[0072] The lubricating oil composition of the invention can further
contain other additives. Examples of other additives include a
viscosity index improver (e.g., dispersant type viscosity improver
or non-dispersant type viscosity improver), a corrosion inhibitor
(e.g., a copper corrosion inhibitor such as thiazol compound,
triazole compound, thiadiazole compound), a seal-swelling agent
(e.g., an oil-soluble dialkylester of a dibasic acid such as adipic
acid, azelaic acid, sebacic acid, or phthalic acid), a dye (e.g.,
red dye), a defoaming agent, and a pour-point depressant (e.g.,
polymethacrylic acid ester, polyacrylic acid ester, and
polyacrylamide).
EXAMPLES
[0073] The present invention is further described by the following
illustrative non-limiting working examples.
Synthesis Example 1
Synthesis of Friction Modifier According to the Invention (bis-type
.beta.-Branched Primary 2-alkenylsuccinimide)
[0074] 2-Octyl-1-dodecene (1 mol), maleic anhydride (1 mol) and
2,2-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)
propionate] (oxidation inhibitor, 0.003 mol) were mixed, and the
mixture was reacted at 200.degree. C. for 4 hours, to give a
primary alkenylsuccinic anhydride. To the alkenylsuccinic anhydride
(1 mol) was added diethylene triamine (0.5 mol). The mixture was
reacted at 160.degree. C. for 2 hours and subsequently dried under
reduced pressure for 30 minutes to yield a reaction product. By IR
spectroscopy, it was confirmed that the reaction product was the
desired bis-type .beta.-branched primary 2-alkenylsuccinimide
(product comprising two alkenylsuccinimide moieties bridged with a
diethylenetriamine residue, nitrogen content: 4.9 wt. %).
Synthesis Example 2
Synthesis of Friction Modifier According to the Invention (bis-type
.beta.-Branched Primary 2-alkenylsuccinimide)
[0075] The procedures of Synthesis Example 1 were repeated except
for replacing diethylenetriamine with triethylenetetramine, to
yield the desired bis-type .beta.-branched primary
2-alkenylsuccinimide (reaction product comprising two
alkenylsuceinimide moieties bridged with a triethylenetetramine
residue).
Synthesis Comparative Example 3
Synthesis of Friction Modifier for Comparison (bis-type
.alpha.-Branched Secondary 2-alkenylsuccinimide)
[0076] To isooctadecenylsuccinic anhydride (prepared by the
reaction of maleic anhydride with octadecene produced by
isomerization (internal olefination) of linear 1-octadecene, 1 mol)
was added diethylenetriamine (0.5 mol). The resulting mixture was
reacted at 160.degree. C. for 2 hours, and subsequently dried under
reduced pressure for 30 minutes, to give a reaction product. By IR
spectroscopy, it was confirmed that the reaction product was the
desired bis-type .alpha.-branched secondary 2-alkenylsuccinimide
(nitrogen content: 5.2 wt. %).
Examples, Reference Examples and Comparison Examples
--Preparation of Lubricating Oil Composition--
[0077] The lubricating oil composition was prepared by adding the
below-described nitrogen-containing ashless dispersant, friction
modifier, metal-containing detergent, oxidation inhibitor,
corrosion inhibitor, phosphorus compound, viscosity index improver,
pour point depressant, seal-swelling agent and defoaming agent in
the below-described amounts to the below-described base oil in the
below-described amount. [0078] (1) Base oil (79.50 wt. %)
[0079] Paraffinic hyper purified mineral oil [0080] (2)
Nitrogen-containing ashless dispersant (3.80 wt. %)
[0081] Borated polyisobutenylsuccinicimide [0082] (3) Friction
modifier 1 (2.50 wt. %)
[0083] Friction modifier prepared in the aforementioned Synthesis
Example 1 for Examples 1 and 2
[0084] Friction modifier prepared in the aforementioned Synthesis
Example 2 for Examples 3 and 4
[0085] Friction modifier prepared in the aforementioned Synthesis
Example 3 for Reference Example [0086] (4) Friction modifier 2
(0.20 wt. %)
[0087] A mixture of a conventional amine-type friction modifier and
a conventional ester-type friction modifier [0088] (5)
Metal-containing detergent (0.60 wt. %)
[0089] A mixture (1/1 by weight) of the following overbased
sulfonate and overbased salicylate
[0090] Overbased sulfonate having an alkyl group containing 20 to
24 carbon atoms and a TBN of approx. 300 mg KOH/g
[0091] Overbased salicylate having an alkyl group containing 14 to
18 carbon atoms and a TBN of approx. 200 mg KOH/g [0092] (6)
Oxidation inhibitor (1.20 wt. %)
[0093] A mixture of an amine-type oxidation inhibitor and a
phenol-type oxidation inhibitor [0094] (7) Corrosion inhibitor
(0.07 wt. %)
[0095] A mixture of a thiadiazol-type corrosion inhibitor and a
benzotriazole-type corrosion inhibitor [0096] (8) Phosphorus
compound (0.30 wt. %)
[0097] Alkyl Phosphite [0098] (9) Viscosity index improver (11.00
wt. %)
[0099] A dispersant-type polymethacrylate viscosity index improver
[0100] (10) Pour-point depressant (0.20 wt. %)
[0101] A polymethacrylate-type pour-point depressant [0102] (11)
Seal-swelling agent (0.60 wt. %)
[0103] A sulforane-type seal-swelling agent [0104] (12)
Defoamer
[0105] A silicon-type defoamer
--Lubricating Oil Composition for Comparison--
[0106] Two commercially available transmission oils (CVTF,
Comparison Oil A and Comparison Oil B) were purchased for
comparison.
--Evaluation Method for Lubricating Oil Composition--
(1) Determination of Friction Coefficient
[0107] The friction coefficient was determined in terms of a
metal-metal friction coefficient by means of a block-on-ring tester
according to "Standard test method for metal on metal friction
characteristics of belt CVT fluids" described in JASO M358:2005.
Details of the testing method are described below. [0108] Testing
conditions [0109] Ring: Falex S-10 Test Ring (SAE 4620 Steel)
[0110] Block: Falex H-60 TEst Block (SAE 01 Steel) [0111] Amount of
oil [0112] 150 mL [0113] Break-in Conditions [0114] Oil
temperature: 110.degree. C. [0115] Load: 5 min. under 890 N and 25
min. under 1112 N [0116] Sliding velocity: 5 min. at 0.5 m/s--25
min. at 1.0 m/s [0117] Testing Conditions [0118] Oil temperature:
110.degree. C. [0119] Load: 1112 N [0120] Sliding velocity: 5 min.
each at 1.0, 0:5, 0.25, 0.125, 0.075, 0.025 m/s [0121] Friction
coefficient: a friction coefficient for 30 sec. before the change
of the sliding velocity
(2) Determination of Anti-Shudder Performance Durability
[0122] The anti-shudder performance durability was determined by
means of a low velocity friction apparatus according to "Road
vehicles--Test method for anti-shudder performance of automatic
transmission fluids" described in JASO M-349:2001. Details of the
testing method are described below. [0123] Testing conditions
[0124] Friction material: cellulose disc/steel plate
[0125] 2Amount of oil: 150 mL [0126] Break-in conditions [0127]
Contact pressure: 1 MPa [0128] Oil temperature: 80.degree. C.
[0129] Sliding velocity: 0.6 m/s [0130] Sliding time: 30 minutes
[0131] .quadrature.V Performance test conditions [0132] Contact
pressure: 1 MPa
[0133] 2Oil temperature: 40, 80, 120.degree. C. [0134] Sliding
velocity: continuously increasing and decreasing between 0 m/s to
1.5 m/s [0135] Durability test conditions [0136] Contact pressure:
1 MPa [0137] Oil temperature: 120.degree. C. [0138] Sliding rate:
0.9 m/s [0139] Time: 30 minutes [0140] Rest time: 1 minute [0141]
Performance measurement time: .mu.-V characteristics was measured
every 24 hour from 0 hour
[0142] Note: The anti-shudder performance was evaluated by
determining a period of time until .mu.d/dV at 0.9 m/s reached 0.
The longer the determined period of time is, the better the
anti-shudder performance is.
--Results of Evaluation of Lubricating Oil Composition--
[0143] The friction coefficient and anti-shudder durability
determined for each lubricating oil arc set forth in Tables 1 and
2.
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4
Friction Syn. Ex. 1 Syn. Ex. 2 Modifier 2.5 wt. % 1.5 wt. % 2.5 wt.
% 1.5 wt. % Friction coefficient 1 m/s 0.084 0.097 0.096 0.103 0.5
m/s 0.114 0.114 0.116 0.117 0.25 m/s 0.128 0.129 0.127 0.129 0.125
m/s 0.137 0.135 0.134 0.134 0.075 m/s 0.140 0.139 0.137 0.138 0.025
m/s 0.144 0.141 0.140 0.141 Average friction 0.125 0.126 0.125
0.127 coefficient Anti-shudder durability 504 288 288 264
(hours)
TABLE-US-00002 TABLE 2 Ref. Example Com. Oil A Com. Oil B Friction
Syn. Ex. 3 Unknown Modifier 2.5 wt. % Unknown Friction coefficient
1 m/s 0.072 0.077 0.085 0.5 m/s 0.098 0.102 0.105 0.25 m/s 0.117
0.123 0.118 0.125 m/s 0.129 0.133 0.125 0.075 m/s 0.134 0.137 0.128
0.025 m/s 0.139 0.141 0.138 Average friction coefficient 0.115
0.119 0.117 Anti-shudder durability 456 192 96 (hours)
Evaluation
[0144] As is apparent from the friction coefficient at each sliding
rate, each of the lubricating oil compositions of Examples 1 to 4
containing the new friction modifier gives a high friction
coefficient at each sliding velocity which less varies in the range
of 1 m/s to 0.025 m/s, and gives a high average friction
coefficient. Moreover, the lubricating oil compositions of Examples
1 to 4 show sufficiently long anti-shudder duration.
[0145] In contrast, the commercially available CVTF (Corn. Oil A)
gives a relatively low friction coefficient and shows a relatively
short anti-shudder duration. The commercially available CVTF (Com.
Oil B) also gives a relatively low friction coefficient and shows a
further shorter anti-shudder duration.
[0146] The lubricating oil composition of Comparison Example which
contained the friction modifier prepared in Synthesis Example 3
shows a long anti-shudder duration but gives a relatively low
friction coefficient.
[0147] Accordingly, it is apparent that the lubricating oil
composition containing a friction modifier of the present invention
shows excellent performances, particularly as transmission oil.
* * * * *