U.S. patent application number 12/598104 was filed with the patent office on 2010-08-05 for lubricating composition containing ashfree antiwear agent based on hydroxypolycarboxylic acid derivative and a molybdenum compound.
Invention is credited to Mark Davies, Jody Kocsis, Patrick E. Mosier.
Application Number | 20100197536 12/598104 |
Document ID | / |
Family ID | 39591642 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100197536 |
Kind Code |
A1 |
Mosier; Patrick E. ; et
al. |
August 5, 2010 |
Lubricating Composition Containing Ashfree Antiwear Agent Based on
Hydroxypolycarboxylic Acid Derivative and a Molybdenum Compound
Abstract
The invention provides a lubricating composition containing an
oil of lubricating viscosity, an oil soluble molybdenum compound,
and an ashless antiwear agent. The invention further provides for a
new antioxidant. The lubricating composition is suitable for
lubricating an internal combustion engine.
Inventors: |
Mosier; Patrick E.; (Bay
Village, OH) ; Kocsis; Jody; (Chagrin Falls, OH)
; Davies; Mark; (Derbyshire, GB) |
Correspondence
Address: |
THE LUBRIZOL CORPORATION;ATTN: DOCKET CLERK, PATENT DEPT.
29400 LAKELAND BLVD.
WICKLIFFE
OH
44092
US
|
Family ID: |
39591642 |
Appl. No.: |
12/598104 |
Filed: |
May 15, 2008 |
PCT Filed: |
May 15, 2008 |
PCT NO: |
PCT/US08/63671 |
371 Date: |
February 16, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60939949 |
May 24, 2007 |
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Current U.S.
Class: |
508/167 ;
508/364; 508/370 |
Current CPC
Class: |
C10M 141/12 20130101;
C10N 2030/45 20200501; C10M 2207/289 20130101; C10M 2207/24
20130101; C10M 2207/028 20130101; C10M 2215/086 20130101; C10M
2219/062 20130101; C10M 2223/045 20130101; C10M 2219/068 20130101;
C10M 2215/224 20130101; C10M 2207/281 20130101; C10M 2207/10
20130101; C10M 2219/089 20130101; C10N 2030/06 20130101; C10M
2223/043 20130101; C10M 2219/046 20130101; C10M 2215/02 20130101;
C10M 2215/082 20130101; C10M 2215/08 20130101; C10N 2040/25
20130101; C10M 2207/262 20130101; C10N 2030/42 20200501; C10N
2030/43 20200501; C10M 2215/28 20130101; C10N 2030/10 20130101;
C10M 2207/10 20130101; C10N 2010/12 20130101; C10M 2215/02
20130101; C10N 2010/12 20130101; C10M 2219/068 20130101; C10N
2010/12 20130101; C10M 2223/045 20130101; C10N 2010/12 20130101;
C10M 2207/10 20130101; C10N 2010/12 20130101; C10M 2215/02
20130101; C10N 2010/12 20130101; C10M 2219/068 20130101; C10N
2010/12 20130101; C10M 2223/045 20130101; C10N 2010/12
20130101 |
Class at
Publication: |
508/167 ;
508/370; 508/364 |
International
Class: |
C10M 141/12 20060101
C10M141/12 |
Claims
1. A lubricating composition comprising an oil of lubricating
viscosity, an oil-soluble molybdenum compound, and an ashless
antiwear agent represented by Formula (1): ##STR00003## wherein Y
and Y' are independently --O--, >NH, >NR.sup.3, or an imide
group formed by taking together both Y and Y' groups and forming a
R.sup.1--N<group between two >C.dbd.O groups; X is
independently --Z--O--Z'--, >CHR.sup.4, >CR.sup.4R.sup.5,
>C(OH)(CO.sub.2R.sup.2), >C(CO.sub.2R.sup.2).sub.2,
>CCH.sub.2CO.sub.2R.sup.2 or >CHOR.sup.6; Z and Z' are
independently >CH.sub.2, >CHR.sup.4, >CR.sup.4R.sup.5,
>C(OH)(CO.sub.2R.sup.2), or >CHOR.sup.6; n is 0 to 10, with
the proviso that when n=1, X is not >CH.sub.2, and when n=2,
both X' s are not simultaneously >CH.sub.2; m is 0 or 1; R.sup.1
is independently hydrogen or a hydrocarbyl group, typically
containing 1 to 150 carbon atoms, with the proviso that when
R.sup.1 is hydrogen, m is 0, and n is more than or equal to 1;
R.sup.2 is a hydrocarbyl group, typically containing 1 to 150
carbon atoms; R.sup.3, R.sup.4 and R.sup.5 are independently
hydrocarbyl groups or hydroxy-containing hydrocarbyl groups or
carboxyl-containing hydrocarbyl groups; and R.sup.6 is hydrogen or
a hydrocarbyl group, typically containing 1 to 150 carbon
atoms.
2. The lubricating composition of claim 1, wherein the ashless
antiwear agent of Formula (1) is derived from at least one
hydroxy-polycarboxylic acid.
3. The lubricating composition of claim 1 wherein the ashless
anti-wear agent comprises a hydroxy-polycarboxylic acid di-ester, a
hydroxy-polycarboxylic acid di-amide, a hydroxyl-polycarboxylic
acid imide, a hydroxy-polycarboxylic acid di-imide, a
hydroxy-polycarboxylic acid ester-amide, a hydroxy-polycarboxylic
acid ester-imide, and a hydroxy-polycarboxylic acid
imide-amide.
4. The lubricating composition of claim 1, wherein the ashless
antiwear agent represented by Formula (1) is an imide, a di-ester,
or a di-amide.
5. The lubricating composition of claim 1, wherein Y and Y' of
Formula (1) are both --O--.
6. The lubricating composition of claim 1, wherein Formula (1)
defines m as 0 or 1, n as 1 to 2, X is >CHOR.sup.6, and R.sup.1,
R.sup.2 and R.sup.6 are independently hydrogen or hydrocarbyl
groups containing 4 to 30 carbon atoms.
7. The lubricating composition of claim 1 wherein the ashless
antiwear agent is derived from tartaric acid or citric acid.
8. The lubricating composition of claim 1, wherein the ashless
antiwear agent is present at 0.05 to 10 wt %, or 0.1 to 5 wt % of
the lubricating composition.
9. The lubricating composition of claim 1, wherein the oil-soluble
molybdenum compound is selected from at least one member of the
group consisting of molybdenum dithiocarbamates, molybdenum
dialkyldithiophosphates, amine salts of molybdenum compounds,
molybdenum xanthates, molybdenum sulphides, molybdenum
carboxylates, and molybdenum alkoxides.
10. The lubricating composition of claim 9, wherein the oil-soluble
molybdenum compound is selected from at least one member of the
group consisting of molybdenum dithiocarbamates, molybdenum
dialkyldithiophosphates, and amine salts of molybdenum
compounds.
11. The lubricating composition of claim 10, wherein the
oil-soluble molybdenum compound is a molybdenum
dithiocarbamate.
12. The lubricating composition of claim 1, wherein the oil-soluble
molybdenum compound is present in an amount to provide 0.5 ppm to
2000 ppm, 1 ppm to 700 ppm, or 20 ppm to 250 ppm of molybdenum.
13. The lubricating composition of claim 1, wherein the lubricating
composition is further characterised as having at least one of (i)
a sulphur content of 0.8 wt % or less, (ii) a phosphorus content of
0.2 wt % or less, or (iii) a sulphated ash content of 2 wt % or
less.
14. The lubricating composition of claim 1, wherein the lubricating
composition is characterised as having (i) a sulphur content of 0.5
wt % or less, (ii) a phosphorus content of 0.1 wt % or less, and
(iii) a sulphated ash content of 1.5 wt % or less.
15. The lubricating composition of claim 1 further comprises at
least one of a friction modifier (other than an oil-soluble
molybdenum compound or a compound of Formula (1)), a viscosity
modifier, an antioxidant (other than the oil-soluble molybdenum
compound), an overbased detergent, a succinimide dispersant, or
mixtures thereof.
16. The lubricating composition of claim 15, wherein the friction
modifier is selected from the group consisting of long chain fatty
amides, long chain fatty esters, long chain fatty epoxide
derivatives, long chain fatty imidazolines, and amine salts of
alkylphosphoric acids.
17. The lubricating composition of claim 1 further comprising a
phosphorus-containing antiwear agent.
18. The lubricating composition of claim 1 further comprising an
overbased detergent.
19. The lubricating composition of claim 18, wherein the overbased
detergent is selected from the group consisting of
non-sulphur-containing phenates, sulphur-containing phenates,
sulphonates, salixarates, salicylates, and mixtures thereof.
20. A method of lubricating an internal combustion engine
comprising, supplying to the internal combustion engine the
lubricating composition of claim 1.
21-22. (canceled)
Description
FIELD OF INVENTION
[0001] The invention provides a lubricating composition containing
an oil of lubricating viscosity, an oil soluble molybdenum
compound, and an ashless antiwear agent. The invention further
provides for a new antioxidant. The lubricating composition is
suitable for lubricating an internal combustion engine.
BACKGROUND OF THE INVENTION
[0002] Engine manufacturers have focused on improving engine design
in order to improve fuel economy and efficiency (typically, based
on Federal Corporate Average Fuel Economy (CAFE) standards). Whilst
improvements in engine design and operation have contributed,
improved formulation of engine oil lubricant may also improve fuel
economy and efficiency. Lubricants function to reduce and disperse
engine deposits which accumulate when the engines are running. They
also serve to reduce the friction between sliding moving parts
(typically metallic or ceramic) that are in contact.
[0003] It is well known for lubricating oils to contain a number of
additives (including antiwear agents, antioxidants, dispersants,
detergents etc.) used to protect the mechanical devices such as
internal combustion engines from wear, oxidation, soot deposits and
acidity build up. A common antiwear additive for engine lubricating
oils is zinc dialkyldithiophosphate (ZDDP). It is believed that
ZDDP antiwear additives protect the engine by forming a protective
film on metal surfaces. ZDDP is also believed to have a detrimental
impact on fuel economy and efficiency. Consequently, engine
lubricants also contain friction modifier to obviate the
detrimental impact of ZDDP on fuel economy and efficiency. Both
ZDDP and friction modifier function by adsorption on sliding
surfaces, and each may interfere with each other's respective
functions.
[0004] Further, engine lubricants containing phosphorus compounds
and sulphur have been shown to contribute in part to particulate
emissions, and emissions of other pollutants. In addition, sulphur
and phosphorus tend to poison the catalysts used in catalytic
converters, resulting in a reduction in performance of said
catalysts.
[0005] With increasing control of emissions (often associated with
contributing to NO.sub.x formation, SO.sub.x formation, formation
of sulphated ash and reducing the efficiency of after-treatment
catalytic converters) there is a desire towards reduced amounts of
sulphur, phosphorus and sulphated ash in engine oils. However,
reducing the levels of antiwear additives such as ZDDP, is likely
to increase wear and result in other detrimental performance of an
engine.
[0006] In addition, as technology develops, components of an engine
are exposed to more severe operating conditions. Operating
conditions may include higher power density engines, use of turbo
chargers, use of alternative fuels and the like. Under many severe
operating conditions, oxidation of lubricant and components occurs
more readily. Thus there is a need to reduce oxidation, that in
turn may also increase equipment longevity, or reliability.
[0007] International Publication WO 2005/087904 discloses a
lubricant composition containing at least one hydroxycarboxylic
acid ester or hydroxy polycarboxylic acid. The lubricant
composition disclosed may also contain zinc
dihydrocarbyldithiophosphates, or other phosphorous-containing
additives such as trilauryl phosphate or
triphenylphosphorothionate. The lubricant composition has anti-wear
or anti-fatigue properties.
[0008] International Publication WO 2006/044411 discloses a
low-sulphur, low-phosphorus, low-ash lubricant composition suitable
for lubricating an internal combustion engine, containing a
tartrate ester, or amide having 1 to 150 carbon atoms per ester of
amide group.
[0009] U.S. Pat. No. 5,338,470 discloses alkylated citric acid
derivatives obtained as a reaction product of citric acid and an
alkyl alcohol or amine. The alkylated citric acid derivative is
effective as an antiwear agent and friction modifier.
[0010] U.S. Pat. No. 4,237,022 discloses tartrimides useful as
additives in lubricants and fuels for effective reduction in squeal
and friction as well as improvement in fuel economy.
[0011] U.S. Pat. No. 4,952,328 discloses lubricating oil
compositions for internal combustion engines, comprising (A) oil of
lubricating viscosity, (B) a carboxylic derivative produced by
reacting a succinic acylating agent with certain amines, and (C) a
basic alkali metal salt of sulphonic or carboxylic acid.
[0012] U.S. Pat. No. 4,326,972 discloses lubricant compositions for
improving fuel economy of internal combustion engines. The
composition includes a specific sulphurised composition (based on
an ester of a carboxylic acid) and a basic alkali metal
sulphonate.
[0013] U.S. Patent Application 60/867,534 discloses malonate esters
suitable as antiwear agents.
[0014] Canadian Patent CA 1 183 125 discloses lubricants for
gasoline engines containing alkyl-ester tartrates, where the sum of
carbon atoms on the alkyl groups is at least 8.
[0015] Consequently, it would be desirable to provide a lubricating
composition capable of providing at least one of (i) reducing or
preventing phosphorus emissions, (ii) reducing or preventing
sulphur emissions, (ii) wholly or partially replacing ZDDP in
lubricating oils, (iii) improving fuel economy, (iv) fuel economy
retention/efficiency, and (v) oxidation control. The present
invention provides an antiwear agent capable of achieving at least
one of (i), (ii) (iii), (iv), and (v). In addition it may also be
desirable for the antiwear agent to not have a detrimental affect
on other components of a mechanical device. It may also be
desirable for the antiwear agent to have antioxidant
performance.
SUMMARY OF THE INVENTION
[0016] In one embodiment the invention provides a lubricating
composition comprising an oil of lubricating viscosity, an
oil-soluble molybdenum compound, and an ashless antiwear agent
represented by Formula (1):
##STR00001##
wherein
[0017] Y and Y' are independently --O--, >NH, >NR.sup.3, or
an imide group formed by taking together both Y and Y' groups and
forming a R.sup.1--N<group between two >C.dbd.O groups;
[0018] X is independently --Z--O--Z'--, >CH.sub.2,
>CHR.sup.4, >CR.sup.4R.sup.5, >C(OH)(CO.sub.2R.sup.2),
>C(CO.sub.2R.sup.2).sub.2, >CCH.sub.2CO.sub.3R.sup.2, or
>CHOR.sup.6;
[0019] Z and Z' are independently >CH.sub.2, >CHR.sup.4,
>CR.sup.4R.sup.5, >C(OH)(CO.sub.2R.sup.2), or
>CHOR.sup.6;
[0020] n is 0 to 10, or 1 to 8, or 1 to 6, or 2 to 6, or 2 to 4,
with the proviso that when n=1, X is not >CH.sub.2, and when
n=2, both X's are not simultaneously >CH.sub.2;
[0021] m is 0 or 1;
[0022] R.sup.1 is independently hydrogen or a hydrocarbyl group,
typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or
11 to 18, or 8 to 10 carbon atoms, with the proviso that when
R.sup.1 is hydrogen, m is 0, and n is more than or equal to 1;
[0023] R.sup.2 is a hydrocarbyl group, typically containing 1 to
150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10
carbon atoms;
[0024] R.sup.3, R.sup.4 and R.sup.5 are independently hydrocarbyl
groups or hydroxy-containing hydrocarbyl groups or
carboxyl-containing hydrocarbyl groups; and
[0025] R.sup.6 is hydrogen or a hydrocarbyl group, typically
containing 1 to 150, or 4 to 30 carbon atoms.
[0026] In one embodiment the lubricating composition is
characterised as having at least one of (i) a sulphur content of
0.8 wt % or less, (ii) a phosphorus content of 0.2 wt % or less, or
(iii) a sulphated ash content of 2 wt % or less.
[0027] In one embodiment the invention the lubricating composition
is characterised as having (i) a sulphur content of 0.5 wt % or
less, (ii) a phosphorus content of 0.1 wt % or less, and (iii) a
sulphated ash content of 1.5 wt % or less.
[0028] In one embodiment the invention provides a method of
lubricating an internal combustion engine comprising, supplying to
the internal combustion engine a lubricating compositions as
disclosed herein.
[0029] In one embodiment the invention provides for the use of a
lubricating composition as disclosed herein for providing at least
one of (i) reducing or preventing phosphorus emissions, (ii)
reducing or preventing sulphur emissions, (ii) wholly or partially
replacing ZDDP in lubricating oils, (iii) improving fuel economy,
and (iv) fuel economy retention/efficiency.
[0030] In one embodiment the invention provides for the use of a
compound of Formula (1) as an antioxidant in a lubricant, wherein
the compound of Formula (1) may be represented by:
##STR00002##
wherein
[0031] Y and Y' are independently --O--, >NH, >NR.sup.3, or
an imide group formed by taking together both Y and Y' groups and
forming a R.sup.1--N<group between two >C.dbd.O groups;
[0032] X is independently --Z--O--Z'--, >CH.sub.2,
>CHR.sup.4, >CR.sup.4R.sup.5, >C(OH)(CO.sub.2R.sup.2),
>C(CO.sub.2R.sup.2).sub.2, or >CHOR.sup.6;
[0033] Z and Z' are independently >CH.sub.2, >CHR.sup.4,
>CR.sup.4R.sup.5, >C(OH)(CO.sub.2R.sup.2), or
>CHOR.sup.6;
[0034] n is 0 to 10, or 1 to 8, or 1 to 6, or 2 to 6, or 2 to 4,
with the proviso that when n=1, X is not >CH.sub.2, and when
n=2, both X's are not >CH.sub.2;
[0035] m is 0 or 1;
[0036] R.sup.1 is independently hydrogen or a hydrocarbyl group,
typically containing 1 to 150, 4 to 30, or 6 to 20, or 10 to 20, or
11 to 18, or 8 to 10 carbon atoms, with the proviso that when
R.sup.1 is hydrogen, m is 0, and n is more than or equal to 1;
[0037] R.sup.2 is a hydrocarbyl group, typically containing 1 to
150, 4 to 30, or 6 to 20, or 10 to 20, or 11 to 18, or 8 to 10
carbon atoms;
[0038] R.sup.3, R.sup.4 and R.sup.5 are independently hydrocarbyl
groups; and
R.sup.6 is hydrogen or a hydrocarbyl group, typically containing 1
to 150, or 4 to 30 carbon atoms.
[0039] In one embodiment the invention provides for the use of the
compound of Formula (1) as an antioxidant in a lubricant, wherein
the compound of Formula (1) is an ester (such as a monoester, a
diester or a triester).
[0040] In one embodiment the invention provides for the use of the
compound of Formula (1) as an antioxidant in a lubricant, wherein
the compound of Formula (1) is not a citrate.
[0041] In one embodiment the invention provides for the use of a
tartaric acid derivative (typically a tartrate ester) as an
antioxidant in a lubricant.
[0042] In one embodiment the invention provides for the use of the
compound of Formula (1) (typically a tartaric acid derivative) as
an antioxidant in an internal combustion engine lubricant.
DETAILED DESCRIPTION OF THE INVENTION
[0043] The present invention provides a lubricating composition and
a method for lubricating an engine as disclosed above.
Oil-Soluble Molybdenum Compound)
[0044] The oil-soluble molybdenum compound may have the functional
performance of an antiwear agent, an antioxidant, a friction
modifier, or mixtures thereof. Typically, the oil-soluble
molybdenum compound includes molybdenum dithiocarbamates,
molybdenum dialkyldithiophosphates, amine salts of molybdenum
compounds, molybdenum xanthates, molybdenum sulphides, molybdenum
carboxylates, molybdenum alkoxides, or mixtures thereof. The
molybdenum sulphides include molybdenum disulphide. The molybdenum
disulphide may be in the form of stable dispersions. In one
embodiment the oil-soluble molybdenum compound may be selected from
the group consisting of molybdenum dithiocarbamates, molybdenum
dialkyldithiophosphates, amine salts of molybdenum compounds, and
mixtures thereof. In one embodiment the oil-soluble molybdenum
compound is a molybdenum dithiocarbamate.
[0045] Suitable examples of molybdenum dithiocarbamates which may
be used as an antioxidant include commercial materials sold under
the trade names such as Molyvan 822.TM. and Molyvan.TM. A from R.
T. Vanderbilt Co., Ltd., and Adeka Sakura-Lube.TM. S-100, S-165,
S-515, and S-600 from Asahi Denka Kogyo K.K and mixtures
thereof.
[0046] The oil-soluble molybdenum compound may be present in an
amount sufficient to provide 0.5 ppm to 2000 ppm, 1 ppm to 700 ppm,
1 ppm to 550 ppm, 5 ppm to 300 ppm, or 20 ppm to 250 ppm of
molybdenum.
Ashless Antiwear Agent
[0047] In one embodiment the compound of Formula (1) is an ashless
antiwear agent, and it may also act as an antioxidant.
[0048] In one embodiment the compound of Formula (1) contains an
imide group. The imide group is typically formed by taking together
the Y and Y' groups and forming a R.sup.1--N<group between two
>C.dbd.O groups.
[0049] In one embodiment the compound of Formula (1) has m, n, X,
and R.sup.1, R.sup.2 and R.sup.6 defined as follows: m is 0 or 1, n
is 1 to 2, X is >CHOR.sup.6, and R.sup.1, R.sup.2 and R.sup.6
are independently hydrocarbyl groups containing 4 to 30 carbon
atoms.
[0050] In one embodiment Y and Y' are both --O--.
[0051] In one embodiment the compound of Formula (1) has m, n, X,
Y, Y' and R.sup.1, R.sup.2 and R.sup.6 defined as follows: m is 0
or 1, n is 1 to 2, X is >CHOR.sup.6; Y and Y' are both --O--,
and R.sup.1, R.sup.2 and R.sup.6 are independently hydrogen or
hydrocarbyl groups containing 4 to 30 carbon atoms.
[0052] In one embodiment the ashless antiwear agent includes
imides, di-esters, di-amides, di-imides, ester-amides,
ester-imides, or imide-amides. In one embodiment the antiwear agent
includes imides, di-esters, di-amides, or ester-amides.
[0053] The di-esters, di-amides, ester-amide, ester-imide compounds
of Formula (1) may be prepared by reacting a dicarboxylic acid
(such as tartaric acid), with an amine or alcohol, optionally in
the presence of a known esterification catalyst. In the case of
ester-imide compounds it is necessary to have at least three
carboxylic acid groups (such as citric acid). In the case of a
di-imide, it is necessary to have at least four carboxylic acid
groups. The amine or alcohol typically has sufficient carbon atoms
to fulfill the requirements of R.sup.1 and/or R.sup.2 as defined in
Formula (1).
[0054] In one embodiment R.sup.1 and R.sup.2 are independently
linear or branched hydrocarbyl groups. In one embodiment the
hydrocarbyl groups are branched. In one embodiment the hydrocarbyl
groups are linear. The R.sup.1 and R.sup.2 may be incorporated into
Formula (1) by either an amine or an alcohol. The alcohol includes
both monohydric alcohol and polyhydric alcohol. The carbon atoms of
the alcohol may be linear chains, branched chains, or mixtures
thereof.
[0055] Examples of a suitable branched alcohol include
2-ethylhexanol, isotridecanol, Guerbet alcohols, or mixtures
thereof.
[0056] Examples of a monohydric alcohol include methanol, ethanol,
propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol,
decanol, undecanol, dodecanol, tridecanol, tetradecanol,
pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol,
eicosanol, or mixtures thereof. In one embodiment the monohydric
alcohol contains 5 to 20 carbon atoms.
[0057] The alcohol includes either a monohydric alcohol or a
polyhydric alcohol. Examples of a suitable polyhydric alcohol
include ethylene glycol, propylene glycol, 1,3-butylene glycol,
2,3-butylene glycol, 1,5-pentane diol, 1,6-hexane diol, glycerol,
sorbitol, pentaerythritol, trimethylolpropane, starch, glucose,
sucrose, methylglucoside, or mixtures thereof. In one embodiment
the polyhydric alcohol is used in a mixture along with a monohydric
alcohol. Typically, in such a combination the monohydric alcohol
constitutes at least 60 mole percent, or at least 90 mole percent
of the mixture.
[0058] In one embodiment ashless antiwear agent is derived from
tartaric acid. The tartaric acid used for preparing the tartrates
of the invention can be commercially available, and it is likely to
exist in one or more isomeric forms such as d-tartaric acid,
l-tartaric acid or mesotartaric acid, often depending on the source
(natural) or method of synthesis (from maleic acid). For example a
racemic mixture of d-tartaric acid and l-tartaric acid is obtained
from a catalysed oxidation of maleic acid with hydrogen peroxide
(with tungstic acid catalyst). These derivatives can also be
prepared from functional equivalents to the diacid readily apparent
to those skilled in the art, such as esters, acid chlorides, or
anhydrides.
[0059] When the compound of Formula (1) is derived from tartaric
acid, resultant tartrates may be solid, semi-solid, or oil
depending on the particular alcohol used in preparing the tartrate.
For use as additives in a lubricating composition the tartrates are
advantageously soluble and/or stably dispersible in such oleaginous
compositions. For example, compositions intended for use in oils
are typically oil-soluble and/or stably dispersible in an oil in
which they are to be used. The term "oil-soluble" as used in this
specification and appended claims does not necessarily mean that
all the compositions in question are miscible or soluble in all
proportions in all oils. Rather, it is intended to mean that the
composition is soluble in an oil (mineral, synthetic, etc.) in
which it is intended to function to an extent which permits the
solution to exhibit one or more of the desired properties.
Similarly, it is not necessary that such "solutions" be true
solutions in the strict physical or chemical sense. They may
instead be micro-emulsions or colloidal dispersions which, for the
purpose of this invention, exhibit properties sufficiently close to
those of true solutions to be, for practical purposes,
interchangeable with them within the context of this invention.
[0060] In one embodiment the ashless antiwear agent includes a
compound derived from a hydroxycarboxylic acid. In one embodiment
the ashless antiwear agent is derived from at least one of
hydroxy-polycarboxylic acid di-ester, a hydroxy-polycarboxylic acid
di-amide, a hydroxy-polycarboxylic acid di-imide, a
hydroxy-polycarboxylic acid ester-amide, a hydroxy-polycarboxylic
acid ester-imide, and a hydroxy-polycarboxylic acid imide-amide. In
one embodiment the ashless antiwear agent is derived from at least
one of the group consisting of a hydroxy-polycarboxylic acid
di-ester, a hydroxy-polycarboxylic acid di-amide, and a
hydroxy-polycarboxylic acid ester-amide.
[0061] Examples of a suitable a hydroxycarboxylic acid include
citric acid, tartaric acid, lactic acid, glycolic acid,
hydroxy-propionic acid, hydroxyglutaric acid, or mixtures thereof.
In one embodiment ashless antiwear agent is derived from tartaric
acid, citric acid, hydroxy-succinic acid, dihydroxy mono-acids,
mono-hydroxy diacids, or mixtures thereof. In one embodiment the
ashless antiwear agent includes a compound derived from tartaric
acid or citric acid. In one embodiment the ashless antiwear agent
includes a compound derived from tartaric acid. In one embodiment
the compound of Formula (1) is not a citrate.
[0062] US Patent Application 2005/198894 discloses suitable
hydroxycarboxylic acid compounds, and methods of preparing the
same.
[0063] Canadian Patent 1183125; US Patent Publication numbers
2006/0183647 and US-2006-0079413; U.S. Patent Application No.
60/867,402; and British Patent 2 105 743 A, all disclose examples
of suitable tartaric acid derivatives.
[0064] In one embodiment the di-esters, di-amides, di-imides,
ester-amide, ester-imide, imide-amide compounds are derived from a
compound of Formula (1). In one embodiment the di-esters,
di-amides, ester-amide, compounds are derived from a compound of
Formula (1).
[0065] A detailed description of methods for preparing suitable
tartrimides (by reacting tartaric acid with a primary amine) is
disclosed in U.S. Pat. No. 4,237,022.
[0066] In one embodiment the ashless antiwear agent includes imide,
di-esters, di-amides, ester-amide derivatives of tartaric acid.
[0067] Examples of a suitable citric acid derivative include
trialkyl citrates or borated trialkyl citrates. Suitable examples
include triethyl citrate, tripentyl citrate with ethyl dipentyl
citrate, borated triethyl citrate, tributyl citrate, triethyl
citrate transesterified with 1,2-propandiol, triethyl O-acetyl
citrate, triethyl citrate octadecyl succinate, or mixtures thereof.
A more detailed description of suitable citrates is disclosed in WO
2005/087904 and U.S. Pat. No. 5,338,470. Other suitable citrates
include 2-ethylhexyl citrate, dodecyl citrate, or mixtures
thereof.
[0068] The ashless antiwear agent of the invention, typically a
tartrate, may also function as rust and corrosion inhibitors,
friction modifiers, antiwear agents and demulsifiers.
[0069] In one embodiment the ashless antiwear agent is not
borated.
[0070] The ashless antiwear agent of the may be present at 0.01 wt
% to 20 wt %, or 0.05 to 10 wt %, or 0.1 to 5 wt % of the
lubricating composition.
Oils of Lubricating Viscosity
[0071] The lubricating composition comprises an oil of lubricating
viscosity. Such oils include natural and synthetic oils, oil
derived from hydrocracking, hydrogenation, and hydrofinishing,
unrefined, refined and re-refined oils and mixtures thereof.
[0072] Unrefined oils are those obtained directly from a natural or
synthetic source generally without (or with little) further
purification treatment.
[0073] Refined oils are similar to the unrefined oils except they
have been further treated in one or more purification steps to
improve one or more properties. Purification techniques are known
in the art and include solvent extraction, secondary distillation,
acid or base extraction, filtration, percolation and the like.
[0074] Re-refined oils are also known as reclaimed or reprocessed
oils, and are obtained by processes similar to those used to obtain
refined oils and often are additionally processed by techniques
directed to removal of spent additives and oil breakdown
products.
[0075] Natural oils useful in making the inventive lubricants
include animal oils, vegetable oils (e.g., castor oil,), mineral
lubricating oils such as liquid petroleum oils and solvent-treated
or acid-treated mineral lubricating oils of the paraffinic,
naphthenic or mixed paraffinic-naphthenic types and oils derived
from coal or shale or mixtures thereof.
[0076] Synthetic lubricating oils are useful and include
hydrocarbon oils such as polymerized, oligomerised, or
interpolymerised olefins (e.g., polybutylenes, polypropylenes,
propyleneisobutylene copolymers); poly(1-hexenes), poly(1-octenes),
timers or oligomers of 1-decene, e.g., poly(1-decenes), such
materials being often referred to as poly .alpha.-olefins, and
mixtures thereof; alkyl-benzenes (e.g. dodecylbenzenes,
tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes);
polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls);
diphenyl alkanes, alkylated diphenyl alkanes, alkylated diphenyl
ethers and alkylated diphenyl sulphides and the derivatives,
analogs and homologs thereof or mixtures thereof.
[0077] Other synthetic lubricating oils include polyol esters (such
as Prolube.RTM.3970), diesters, liquid esters of
phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl
phosphate, and the diethyl ester of decane phosphonic acid), or
polymeric tetrahydrofurans. Synthetic oils may be produced by
Fischer-Tropsch reactions and typically may be hydroisomerised
Fischer-Tropsch hydrocarbons or waxes. In one embodiment oils may
be prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure
as well as other gas-to-liquid oils.
[0078] Oils of lubricating viscosity may also be defined as
specified in the American Petroleum Institute (API) Base Oil
Interchangeability Guidelines. The five base oil groups are as
follows: Group I (sulphur content >0.03 wt %, and/or <90 wt %
saturates, viscosity index 80-120); Group II (sulphur content
.ltoreq.0.03 wt %, and .gtoreq.90 wt % saturates, viscosity index
80-120); Group III (sulphur content .ltoreq.0.03 wt %, and
.gtoreq.90 wt % saturates, viscosity index .gtoreq.120); Group IV
(all polyalphaolefins (PAOs)); and Group V (all others not included
in Groups I, II, III, or IV). The oil of lubricating viscosity
comprises an API Group I, Group II, Group III, Group IV, Group V
oil or mixtures thereof. Often the oil of lubricating viscosity is
an API Group I, Group II, Group III, Group IV oil or mixtures
thereof. Alternatively the oil of lubricating viscosity is often an
API Group II, Group III or Group IV oil or mixtures thereof.
[0079] The amount of the oil of lubricating viscosity present is
typically the balance remaining after subtracting from 100 wt % the
sum of the amount of the ashless antiwear agent, the oil-soluble
molybdenum compound and the other performance additives.
[0080] The lubricating composition may be in the form of a
concentrate and/or a fully formulated lubricant. If the lubricating
composition of the invention (comprising (i) the ashless antiwear
agent and (ii) the oil-soluble molybdenum compound) is in the form
of a concentrate (which may be combined with additional oil to
form, in whole or in part, a finished lubricant), the ratio of the
of components of the invention to the oil of lubricating viscosity
and/or to diluent oil include the ranges of 1:99 to 99:1 by weight,
or 80:20 to 10:90 by weight.
Other Performance Additives
[0081] The composition optionally comprises other performance
additives. The other performance additives comprise at least one of
metal deactivators, viscosity modifiers, detergents, friction
modifiers (other than an oil-soluble molybdenum compound or a
compound of Formula (1)), antiwear agents (other than the ashless
antiwear agent of the invention), corrosion inhibitors,
dispersants, dispersant viscosity modifiers, extreme pressure
agents, antioxidants (other than an oil-soluble molybdenum compound
of the invention), foam inhibitors, demulsifiers, pour point
depressants, seal swelling agents and mixtures thereof. Typically,
fully-formulated lubricating oil will contain one or more of these
performance additives.
[0082] In one embodiment the lubricating composition comprises the
ashless antiwear agent and further comprises at least one of a
viscosity modifier, an antioxidant, an overbased detergent, a
succinimide dispersant, or mixtures thereof.
[0083] In one embodiment the lubricating composition comprising the
ashless antiwear agent further comprises a phosphorus-containing
antiwear agent.
Detergents
[0084] The lubricant composition optionally further comprises other
known neutral or overbased detergents. Suitable detergent
substrates include phenates, sulphur containing phenates,
sulphonates, salixarates, salicylates, carboxylic acid, phosphorus
acid, mono- and/or di-thiophosphoric acid, alkyl phenol, sulphur
coupled alkyl phenol compounds, or saligenins. Various overbased
detergents and their methods of preparation are described in
greater detail in numerous patent publications, including
WO2004/096957 and references cited therein. The detergent substrate
is typically salted with a metal such as calcium, magnesium,
potassium, sodium, or mixtures thereof. In one embodiment the
lubricating composition further includes an overbased detergent.
Typically the overbased detergent includes phenates, sulphur
containing phenates, sulphonates, salixarates, salicylates, or
mixtures thereof.
[0085] The detergent may be present at 0 wt % to 10 wt %, or 0.1 wt
% to 8 wt %, or 1 wt % to 4 wt %, or greater than 4 to 8 wt %.
Dispersants
[0086] Dispersants are often known as ashless-type dispersants
because, prior to mixing in a lubricating oil composition, they do
not contain ash-forming metals and they do not normally contribute
any ash forming metals when added to a lubricant and polymeric
dispersants. Ashless type dispersants are characterised by a polar
group attached to a relatively high molecular weight hydrocarbon
chain. Typical ashless dispersants include N-substituted long chain
alkenyl succinimides. Examples of N-substituted long chain alkenyl
succinimides include polyisobutylene succinimide with number
average molecular weight of the polyisobutylene substituent in the
range 350 to 5000, or 500 to 3000. Succinimide dispersants and
their preparation are disclosed, for instance in U.S. Pat. No.
3,172,892 or U.S. Pat. No. 4,234,435 or in EP 0355895. Succinimide
dispersants are typically the imide formed from a polyamine,
typically a poly(ethyleneamine).
[0087] In one embodiment the invention further comprises at least
one polyisobutylene succinimide dispersant derived from
polyisobutylene with number average molecular weight in the range
350 to 5000, or 500 to 3000. The polyisobutylene succinimide may be
used alone or in combination with other dispersants.
[0088] In one embodiment the invention further comprises at least
one dispersant derived from polyisobutylene succinic anhydride, an
amine and zinc oxide to form a polyisobutylene succinimide complex
with zinc. The polyisobutylene succinimide complex with zinc may be
used alone or in combination.
[0089] Another class of ashless dispersant is Mannich bases.
Mannich dispersants are the reaction products of alkyl phenols with
aldehydes (especially formaldehyde) and amines (especially
polyalkylene polyamines). The alkyl group typically contains at
least 30 carbon atoms.
[0090] The dispersants may also be post-treated by conventional
methods by a reaction with any of a variety of agents. Among these
are boron, urea, thiourea, dimercaptothiadiazoles, carbon
disulphide, aldehydes, ketones, carboxylic acids,
hydrocarbon-substituted succinic anhydrides, maleic anhydride,
nitriles, epoxides, and phosphorus compounds.
[0091] The dispersant may be present at 0 wt % to 20 wt %, or 0.1
wt % to 15 wt %, or 0.1 wt % to 10 wt %, or 1 wt % to 6 wt %, or 7
wt % to 12 wt % of the lubricating composition.
Antioxidants
[0092] Antioxidant compounds are known and include for example,
sulphurised olefins (typically sulphurised 4-carbobutoxy
cyclohexane, or triphenylphosphite equivalents thereof, or olefin
sulphide), alkylated diphenylamines (e.g., nonyl diphenylamine,
typically di-nonyl diphenylamine, octyl diphenylamine, di-octyl
diphenylamine), hindered phenols, or mixtures thereof. Antioxidant
compounds may be used alone or in combination. The antioxidant may
be present in ranges 0 wt % to 20 wt %, or 0.1 wt % to 10 wt %, or
1 wt % to 5 wt %, of the lubricating composition.
[0093] The hindered phenol antioxidant often contains a secondary
butyl and/or a tertiary butyl group as a sterically hindering
group. The phenol group is often further substituted with a
hydrocarbyl group and/or a bridging group linking to a second
aromatic group. Examples of suitable hindered phenol antioxidants
include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol,
4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol
or 4-butyl-2,6-di-tert-butylphenol, or
4-dodecyl-2,6-di-tert-butylphenol. In one embodiment the hindered
phenol antioxidant is an ester and may include, e.g., Irganox.TM.
L-135 from Ciba or an addition product derived from
2,6-di-tert-butylphenol and an alkyl acrylate, wherein the alkyl
group may contain 1 to 18, or 2 to 12, or 2 to 8, or 2 to 6, or 4
carbon atoms. A more detailed description of suitable
ester-containing hindered phenol antioxidant chemistry is found in
U.S. Pat. No. 6,559,105.
[0094] In one embodiment the lubricant does not contain (or
contains reduced amounts of) phenolic antioxidant, when the
compound of Formula (1) is employed. This embodiment may be useful
because the compound of Formula (1) may be used as a partial or
whole replacement for phenolic antioxidants. It is believed that
during the preparation of tertiary butyl phenols trace amounts of
an impurity tris-tert-butyl phenol are formed and retained in the
final product. Tris-tert-butyl phenol is known to bioaccumulate and
builds up to high concentrations in sediment. Thus employing the
compound of Formula (1) as an antioxidant may allow for reduction
of bioaccumulants.
Viscosity Modifiers
[0095] Viscosity modifiers include hydrogenated copolymers of
styrene-butadiene, ethylene-propylene copolymers, polyisobutenes,
hydrogenated styrene-isoprene polymers, hydrogenated isoprene
polymers, polymethacrylates, polyacrylates, polyalkyl styrenes,
hydrogenated alkenyl aryl conjugated diene copolymers, polyolefins,
esters of maleic anhydride-styrene copolymers, or esters of
(alpha-olefin maleic anhydride) copolymers, or mixtures
thereof.
Dispersant Viscosity Modifiers
[0096] Dispersant viscosity modifiers (often referred to as DVM),
include functionalised polyolefins, for example, ethylene-propylene
copolymers that have been functionalised with the reaction product
of an acylating agent (such as maleic anhydride) and an amine;
polymethacrylates functionalised with an amine, or esterified
maleic anhydride-styrene copolymers reacted with an amine.
[0097] The total amount of viscosity modifier and/or dispersant
viscosity modifier may be 0 wt % to 20 wt %, 0.1 wt % to 15 wt %,
or 0.1 wt % to 10 wt %, of the lubricating composition.
Antiwear Agents
[0098] The lubricant composition optionally further comprises at
least one other antiwear agent other than the ashless antiwear
agent of the invention. Examples of suitable antiwear agents
include phosphate esters, sulphurised olefins, sulphur-containing
anti-wear additives including metal dihydrocarbyldithiophosphates
(such as zinc dialkyldithiophosphates), thiocarbamate-containing
compounds including, thiocarbamate esters, alkylene-coupled
thiocarbamates, and bis(S-alkyldithiocarbamyl) disulphides.
[0099] The dithiocarbamate-containing compounds may be prepared by
reacting a dithiocarbamate acid or salt with an unsaturated
compound. The dithiocarbamate containing compounds may also be
prepared by simultaneously reacting an amine, carbon disulphide and
an unsaturated compound. Generally, the reaction occurs at a
temperature of 25.degree. C. to 125.degree. C. U.S. Pat. Nos.
4,758,362 and 4,997,969 describe dithiocarbamate compounds and
methods of making them.
[0100] Examples of suitable olefins that may be sulphurised to form
an the sulphurised olefin include propylene, butylene, isobutylene,
pentene, hexane, heptene, octane, nonene, decene, undecene,
dodecene, undecyl, tridecene, tetradecene, pentadecene, hexadecene,
heptadecene, octadecene, octadecenene, nonodecene, eicosene or
mixtures thereof. In one embodiment, hexadecene, heptadecene,
octadecene, octadecenene, nonodecene, eicosene or mixtures thereof
and their dimers, trimers and tetramers are especially useful
olefins. Alternatively, the olefin may be a Diels-Alder adduct of a
diene such as 1,3-butadiene and an unsaturated ester, such as,
butylacrylate.
[0101] Another class of sulphurised olefin includes fatty acids and
their esters. The fatty acids are often obtained from vegetable oil
or animal oil and typically contain 4 to 22 carbon atoms. Examples
of suitable fatty acids and their esters include triglycerides,
oleic acid, linoleic acid, palmitoleic acid or mixtures thereof.
Often, the fatty acids are obtained from lard oil, tall oil, peanut
oil, soybean oil, cottonseed oil, sunflower seed oil or mixtures
thereof. In one embodiment fatty acids and/or ester are mixed with
olefins, such such as .alpha.-olefins.
[0102] In an alternative embodiment, the ashless antiwear agent
(which may also be described as a friction modifier) may be a
monoester of a polyol and an aliphatic carboxylic acid, often an
acid containing 12 to 24 carbon atoms. Often the monoester of a
polyol and an aliphatic carboxylic acid is in the form of a mixture
with a sunflower oil or the like, which may be present in the
ashless antiwear agent mixture include 5 to 95, or in other
embodiments 10 to 90, or 20 to 85, or 20 to 80 weight percent of
said mixture. The aliphatic carboxylic acids (especially a
monocarboxylic acid) which form the esters are those acids
typically containing 12 to 24 or 14 to 20 carbon atoms. Examples of
carboxylic acids include dodecanoic acid, stearic acid, lauric
acid, behenic acid, and oleic acid.
[0103] Polyols include diols, triols, and alcohols with higher
numbers of alcoholic OH groups. Polyhydric alcohols include
ethylene glycols, including di-, tri- and tetraethylene glycols;
propylene glycols, including di-, tri- and tetrapropylene glycols;
glycerol; butanediol; hexanediol; sorbitol; arabitol; mannitol;
sucrose; fructose; glucose; cyclohexane diol; erythritol; and
pentaerythritols, including di- and tripentaerythritol. Often the
polyol is diethyl-ene glycol, triethylene glycol, glycerol,
sorbitol, pentaerythritol or dipentaerythritol. The commercial
material known as glycerol monooleate is believed to include about
60.+-.5 percent by weight of the chemical species "glycerol
monooleate," along with 35.+-.5 percent glycerol dioleate, and less
than about 5 percent trioleate and oleic acid. The amounts of the
monoesters, described below, are the amounts of the commercial
grade material.
[0104] The antiwear agent may be present in ranges including 0 wt %
to 15 wt %, or 0 wt % to 10 wt %, or 0.05 wt % to 5 wt %, or 0.1 wt
% to 3 wt % of the lubricating composition.
[0105] In one embodiment the lubricating composition is free of
zinc dihydrocarbyl dithiophosphate. In one embodiment the
lubricating composition further includes zinc dihydrocarbyl
dithiophosphate.
Extreme Pressure Agents
[0106] Extreme Pressure (EP) agents that are soluble in the oil
include sulphur- and chlorosulphur-containing EP agents,
chlorinated hydrocarbon EP agents and phosphorus EP agents.
Examples of such EP agents include chlorinated wax; organic
sulphides and polysulphides such as dibenzyldisulphide,
bis-(chlorobenzyl) disulphide, dibutyl tetrasulphide, sulphurised
methyl ester of oleic acid, sulphurised alkylphenol, sulphurised
dipentene, sulphurised terpene, and sulphurised Diels-Alder
adducts; phosphosulphurised hydrocarbons such as the reaction
product of phosphorus sulphide with turpentine or methyl oleate;
phosphorus esters such as the dihydrocarbon and trihydrocarbon
phosphites, e.g., dibutyl phosphite, diheptyl phosphite,
dicyclohexyl phosphite, pentylphenyl phosphite; dipentylphenyl
phosphite, tridecyl phosphite, distearyl phosphite and
polypropylene substituted phenyl phosphite; metal thiocarbamates
such as zinc dioctyldithiocarbamate and barium heptylphenol diacid;
amine salts of alkyl and dialkylphosphoric acids, including, for
example, the amine salt of the reaction product of a
dialkyldithiophosphoric acid with propylene oxide; and mixtures
thereof.
Friction Modifiers
[0107] In one embodiment the further comprises a friction modifier,
or mixtures thereof. Typically the friction modifier may be present
in ranges including 0 wt % to 10 wt %, or 0.05 wt % to 8 wt %, or
0.1 wt % to 4 wt %.
[0108] Examples of suitable friction modifiers include long chain
fatty acid derivatives of long chain fatty acid derivatives of
amines, esters, or epoxides; fatty imidazolines (that is, long
chain fatty amides, long chain fatty esters, long chain fatty
epoxide derivatives, and long chain fatty imidazolines); and amine
salts of alkylphosphoric acids.
[0109] Friction modifiers may also encompass materials such as
sulphurised fatty compounds and olefins, triglycerides (e.g.
sunflower oil) or monoester of a polyol and an aliphatic carboxylic
acid (all these friction modifiers have been described as
antioxidants or antiwear agents).
[0110] In one embodiment the friction modifier is a long chain
fatty amide, a long chain fatty ester, a long chain fatty epoxide
derivatives, or a long chain fatty imidazoline.
[0111] In one embodiment the friction modifier is a long chain
fatty acid ester (previously described above as an ashless antiwear
agent). In another embodiment the long chain fatty acid ester is a
mono-ester and in another embodiment the long chain fatty acid
ester is a (tri)glyceride.
Other Additives
[0112] Other performance additives such as corrosion inhibitors
include those described in paragraphs 5 to 8 of US Application
US05/038319 (filed on Oct. 25, 2004 McAtee and Boyer as named
inventors), octylamine octanoate, and condensation products of
dodecenyl succinic acid or anhydride and a fatty acid such as oleic
acid with a polyamine. In one embodiment the corrosion inhibitors
include the Synalox.RTM. corrosion inhibitor. The Synalox.RTM.
corrosion inhibitor is typically a homopolymer or copolymer of
propylene oxide. The Synalox.RTM. corrosion inhibitor is described
in more detail in a product brochure with Form No. 118-01453-0702
AMS, published by The Dow Chemical Company. The product brochure is
entitled "SYNALOX Lubricants, High-Performance Polyglycols for
Demanding Applications."
[0113] Metal deactivators including derivatives of benzotriazoles
(typically tolyltriazole), dimercaptothiadiazole derivatives,
1,2,4-triazoles, benzimidazoles, 2-alkyldithiobenzimidazoles, or
2-alkyldithiobenzothiazoles; foam inhibitors including copolymers
of ethyl acrylate and 2-ethylhexylacrylate and optionally vinyl
acetate; demulsifiers including trialkyl phosphates, polyethylene
glycols, polyethylene oxides, polypropylene oxides and (ethylene
oxide-propylene oxide) polymers; pour point depressants including
esters of maleic anhydride-styrene, polymethacrylates,
polyacrylates or polyacrylamides.
INDUSTRIAL APPLICATION
[0114] The lubricating composition may be utilised in a range of
surfaces typically found in mechanical devices, including
aluminum-alloy surfaces. The mechanical devices include an internal
combustion engine, a gearbox, an automatic transmission, a
hydraulic or a turbine. Typically the lubricating composition may
be an engine oil, a gear oil, an automatic transmission oil, a
hydraulic fluid, a turbine oil, a metal working fluid or a
circulating oil. In one embodiment the mechanical device is an
internal combustion engine.
[0115] In one embodiment the internal combustion engine may be a
diesel fuelled engine, a gasoline fuelled engine, a natural gas
fuelled engine or a mixed gasoline/alcohol fuelled engine. In one
embodiment the internal combustion engine may be a diesel fuelled
engine and in another embodiment a gasoline fuelled engine.
[0116] The internal combustion engine may be a 2-stroke or 4-stroke
engine. Suitable internal combustion engines include marine diesel
engines, aviation piston engines, low-load diesel engines, and
automobile and truck engines.
[0117] In one embodiment the internal combustion engine contains
components of an aluminium-alloy. The aluminium-alloy includes
aluminium silicates, aluminium oxides, or other ceramic materials.
In one embodiment the aluminium-alloy is an aluminium-silicate
surface. As used herein, the term "aluminum alloy" is intended to
be synonymous with "aluminium composite" and to describe a
component or surface comprising aluminium and another component
intermixed or reacted on a microscopic or nearly microscopic level,
regardless of the detailed structure thereof. This would include
any conventional alloys with metals other than aluminium as well as
composite or alloy-like structures with non-metallic elements or
compounds such as with ceramic-like materials.
[0118] The lubricant composition for an internal combustion engine
may be suitable for any engine lubricant irrespective of the
sulphur, phosphorus or sulphated ash (ASTM D-874) content. The
sulphur content of the engine oil lubricant may be 1 wt % or less,
or 0.8 wt % or less, or 0.5 wt % or less, or 0.3 wt % or less. In
one embodiment the sulphur content may be in the range of 0.001 wt
% to 0.5 wt %, or 0.01 wt % to 0.3 wt %. The phosphorus content may
be 0.2 wt % or less, or 0.1 wt % or less, or 0.085 wt % or less, or
even 0.06 wt % or less, 0.055 wt % or less, or 0.05 wt % or less.
In one embodiment the phosphorus content may be 100 ppm to 1000
ppm, or 325 ppm to 700 ppm. The total sulphated ash content may be
2 wt % or less, or 1.5 wt % or less, or 1.1 wt % or less, or 1 wt %
or less, or 0.8 wt % or less, or 0.5 wt % or less. In one
embodiment the sulphated ash content may be 0.05 wt % to 0.9 wt %,
or 0.1 wt % or 0.2 wt % to 0.45 wt %. In another embodiment the
sulphur content is 0.4 wt % or less, the phosphorus content is 0.08
wt % or less, and the sulphated ash is 1 wt % or less. In yet
another embodiment the sulfur content is 0.3 wt % or less, the
phosphorus content is 0.05 wt % or less, and the sulphated ash is
0.8 wt % or less.
[0119] In one embodiment the lubricating composition is an engine
oil,
[0120] wherein the lubricating composition is characterised as
having (i) a sulphur content of 0.5 wt % or less, (ii) a phosphorus
content of 0.1 wt % or less, and (iii) a sulphated ash content of
1.5 wt % or less.
[0121] In one embodiment the lubricating composition is suitable
for a 2-stroke or a 4-stroke marine diesel internal combustion
engine. In one embodiment the marine diesel combustion engine is a
2-stroke engine. The ashless antiwear agent of the invention may be
added to a marine diesel lubricating composition at 0.01 to 20 wt
%, or 0.05 to 10 wt %, or 0.1 to 5 wt %.
[0122] The following examples provide illustrations of the
invention. These examples are non-exhaustive and are not intended
to limit the scope of the invention.
EXAMPLES
[0123] As used herein all of the quantities for dispersants,
detergents and viscosity modifiers shown below include conventional
amount of diluent oil Typically the diluent oil constitutes 20 wt %
to 90 wt % of each component. For antiwear agents, corrosion
inhibitors, antioxidants the amounts shown are on an actives basis
i.e. excluding diluent oil because the components are typically not
carried in diluent oil.
Example 1 (EX1)
[0124] A lubricating composition is prepared containing 1 wt % of
di-2-ethylhexyl tartrate, 0.6 wt % of other antiwear agents, 7.9 wt
% of dispersants, 1.5 wt % of detergents, 3.6 wt % of antioxidants
including an effective amount of molybdenum dithiocarbamate, 6.1 wt
% of viscosity modifier, 0.1 wt % of corrosion inhibitor, and 0.1
wt % of friction modifier. The lubricating composition has a
sulphated ash content of 0.6 wt %, a phosphorus content of about
570 ppm, and a sulphur content of 0.17 wt %.
Example 2 (EX2)
[0125] A lubricating composition is prepared containing 1 wt % of a
C.sub.12-14-alkyl tartrate, 4.1 wt % of dispersants, 1.4 wt % of
detergents, 2.5 wt % of antioxidants including 0.7 wt % of
molybdenum dithiocarbamate (commercially available as
Sakuralube.TM.515, manufactured by Asahi Denka), 0.56 wt % of
antiwear agents, 0.1 wt % of corrosion inhibitor, and 0.1 wt % of
friction modifier. The lubricating composition has a phosphorus
content of about 560 ppm.
Comparative Example 1 (CE1)
[0126] is similar to Example 2 except the composition does not
contain 0.7 wt % of molybdenum dithiocarbamate, nor 1 wt % of a
C.sub.12-14-alkyl tartrate.
Comparative Example 2 (CE2)
[0127] is similar to Example 2 except the composition does not
contain 0.7 wt % of molybdenum dithiocarbamate.
Comparative Example 3 (CE3)
[0128] is similar to Example 2 except the composition does not
contain 1 wt % of a C.sub.12-14-alkyl tartrate.
[0129] 10 g samples of the examples above are each treated with one
volume percent of cumene hydroperoxide. The samples (2 ml portions)
are then evaluated for wear performance in an isothermal
temperature high frequency reciprocating rig (HFRR) available from
PCS Instruments. HFRR conditions for the evaluations are 500 g
load, 75 minute duration, 1000 micrometer stroke, 20 hertz
frequency, and at 105.degree. C. Wear scar in micrometers and film
formation as percent film thickness are then measured with lower
wear scar values and higher film formation values indicating
improved wear performance. The results obtained are:
TABLE-US-00001 Tartrate Wear Scar Film Thickness Examples (.mu.m)
(%) EX2 169 95 CE1 358 1 CE2 188 88 CE3 189 57
[0130] Overall the results indicate that the lubricating
composition of the invention is capable of providing at least one
of (i) reducing or preventing phosphorus emissions, (ii) reducing
or preventing sulphur emissions, (ii) wholly or partially replacing
ZDDP in lubricating oils, (iii) improving fuel economy, and (iv)
fuel economy retention/efficiency.
Example 3 (EX3)
[0131] A lubricating composition is designed to meet Euro 4 and
Euro 5 emission standards and containing 1 wt % of C.sub.8-10 alkyl
tartrate. The lubricating composition has a phosphorus content of
900 ppm or less, 0.3 wt % or less of sulphur, and 0.9 wt % or less
of sulphated ash.
Example 4 (EX4)
[0132] A lubricating composition is designed to meet Euro 4 and
Euro 5 emission standards and containing 1 wt % of C.sub.8-10 alkyl
tartrate. The lubricating composition has a phosphorus content of
500 ppm or less, 0.2 wt % or less of sulphur, and 0.5 wt % or less
of sulphated ash.
Comparative Examples 4 (CE4) and 5 (CE5)
[0133] are lubricating composition similar to EX3 and EX4
respectively, except the C.sub.8-10 alkyl tartrate is not
included.
[0134] An iron-catalysed bulk oxidation test is carried out on EX3,
EX4, CE4 and CE5. The test is run at 170.degree. C., with an air
flow of 10 litres per hour, and in the presence of 360 ppm of iron
catalyst. Oxidation is measured by the monitoring the peak area
increase of the CO stretch from FT-IR. The results obtained for EX4
and CE5 indicate that the relative peak area increases by 383 units
for EX4. In contrast, the relative peak area increases by 428 units
for CE5. Thus using a compound within the definition of Formula (1)
of the present invention reduces oxidation of a lubricant
(especially an internal combustion engine).
[0135] It is known that some of the materials described above may
interact in the final formulation, so that the components of the
final formulation may be different from those that are initially
added. The products formed thereby, including the products formed
upon employing lubricant composition of the present invention in
its intended use, may not be susceptible of easy description.
Nevertheless, all such modifications and reaction products are
included within the scope of the present invention; the present
invention encompasses lubricant composition prepared by admixing
the components described above.
[0136] Each of the documents referred to above is incorporated
herein by reference. Except in the Examples, or where otherwise
explicitly indicated, all numerical quantities in this description
specifying amounts of materials, reaction conditions, molecular
weights, number of carbon atoms, and the like, are to be understood
as modified by the word "about." Unless otherwise indicated, each
chemical or composition referred to herein should be interpreted as
being a commercial grade material which may contain the isomers,
by-products, derivatives, and other such materials which are
normally understood to be present in the commercial grade. However,
the amount of each chemical component is presented exclusive of any
solvent or diluent oil, which may be customarily present in the
commercial material, unless otherwise indicated. It is to be
understood that the upper and lower amount, range, and ratio limits
set forth herein may be independently combined. Similarly, the
ranges and amounts for each element of the invention may be used
together with ranges or amounts for any of the other elements.
[0137] As used herein, the term "hydrocarbyl substituent" or
"hydrocarbyl group" is used in its ordinary sense, which is
well-known to those skilled in the art. Specifically, it refers to
a group having a carbon atom directly attached to the remainder of
the molecule and having predominantly hydrocarbon character.
Examples of hydrocarbyl groups include:
[0138] (i) hydrocarbon substituents, that is, aliphatic (e.g.,
alkyl or alkenyl), alicyclic (e.g., cyclo alkyl, cycloalkenyl)
substituents, and aromatic-, aliphatic-, and alicyclic-substituted
aromatic substituents, as well as cyclic substituents wherein the
ring is completed through another portion of the molecule (e.g.,
two substituents together form a ring);
[0139] (ii) substituted hydrocarbon substituents, that is,
substituents containing non-hydrocarbon groups which, in the
context of this invention, do not alter the predominantly
hydrocarbon nature of the substituent (e.g., halo (especially
chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto,
nitro, nitroso, and sulphoxy);
[0140] (iii) hetero substituents, that is, substituents which,
while having a predominantly hydrocarbon character, in the context
of this invention, contain other than carbon in a ring or chain
otherwise composed of carbon atoms.
[0141] Heteroatoms include sulphur, oxygen, nitrogen, and encompass
substituents as pyridyl, furyl, thienyl and imidazolyl. In general,
no more than two, preferably no more than one, non-hydrocarbon
substituent will be present for every ten carbon atoms in the
hydrocarbyl group; typically, there will be no non-hydrocarbon
substituents in the hydrocarbyl group.
[0142] While the invention has been explained in relation to its
preferred embodiments, it is to be understood that various
modifications thereof will become apparent to those skilled in the
art upon reading the specification. Therefore, it is to be
understood that the invention disclosed herein is intended to cover
such modifications as fall within the scope of the appended
claims.
[0143] The antiwear agent described herein may be an oil-soluble
derivative of a molecule containing a first carboxy group and at
least one additional --OH, --NHR, or .dbd.O moiety separated from
the carbon of said first carboxy group by a chain of 2 or 3 atoms,
where R is hydrogen or alkyl, e.g, C1-6 alkyl.
* * * * *