U.S. patent application number 11/386536 was filed with the patent office on 2006-10-05 for lubricating oil composition with reduced phosphorus levels.
Invention is credited to Vincent James Gatto, William Emil Moehle.
Application Number | 20060223724 11/386536 |
Document ID | / |
Family ID | 36012955 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060223724 |
Kind Code |
A1 |
Gatto; Vincent James ; et
al. |
October 5, 2006 |
Lubricating oil composition with reduced phosphorus levels
Abstract
This invention is generally related to a low phosphorus
lubricant for an internal combustion engine that provides superior
deposit control while still retaining excellent viscosity
control.
Inventors: |
Gatto; Vincent James; (Baton
Rouge, LA) ; Moehle; William Emil; (Baton Rouge,
LA) |
Correspondence
Address: |
EDGAR SPIELMAN;ALBEMARLE CORPORATION
451 FLORIDA BLVD.
BATON ROUGE
LA
70801
US
|
Family ID: |
36012955 |
Appl. No.: |
11/386536 |
Filed: |
March 21, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60665961 |
Mar 29, 2005 |
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Current U.S.
Class: |
508/545 |
Current CPC
Class: |
C10M 141/06 20130101;
C10M 169/04 20130101; C10N 2040/25 20130101; C10M 169/045 20130101;
C10M 2205/0285 20130101; C10N 2030/10 20130101; C10N 2030/38
20200501; C10N 2030/40 20200501; C10M 2219/068 20130101; C10N
2010/04 20130101; C10M 2219/022 20130101; C10N 2010/12 20130101;
C10M 2203/1006 20130101; C10M 169/048 20130101; C10M 2207/2845
20130101; C10N 2030/50 20200501; C10M 2207/024 20130101; C10N
2030/04 20130101; C10N 2030/74 20200501; C10M 2207/283 20130101;
C10M 2207/281 20130101; C10M 2207/2835 20130101; C10M 2207/2825
20130101; C10N 2030/42 20200501; C10M 141/10 20130101; C10M 169/044
20130101; C10M 2207/026 20130101; C10M 2215/064 20130101; C10M
2223/045 20130101; C10M 2207/026 20130101; C10M 2207/026
20130101 |
Class at
Publication: |
508/545 |
International
Class: |
C10M 133/06 20060101
C10M133/06 |
Claims
1. A low phosphorus engine oil comprising:
4,4'-methylenebis(2,6-di-tert-butylphenol) and an alkylated
diphenylamine; wherein the weight ratio of
4,4'-methylenebis(2,6-di-tert-butylphenol) to said alkylated
diphenylamine is greater than or equal to about 0.5; and said
engine oil produces less than or equal to 35 mg of total deposits
according to a ASTM D7097 measurement.
2. An engine oil according to claim 1, further comprising a zinc
dialkyldithiophosphate; wherein said engine oil comprises about 600
ppm or less of phosphorus derived from said zinc
dialkyldithiophosphate.
3. An engine oil according to claim 2, further comprising an oil
soluble organomolybdenum compound.
4. A composition comprising: (a) a major amount of oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks; (b)
4,4'-methylenebis(2,6-di-tert-butylphenol); (c) an alkylated
diphenylamine; (d) at least one component selected from the group
consisting of dispersants and detergents; and (e) a zinc
dialkyldithiophosphate; wherein said composition comprises about
600 ppm or less of phosphorus derived from said zinc
dialkyldithiophosphate; and the weight ratio of (b) to (c) is
greater than or equal to about 0.5.
5. A composition according to claim 4, further comprising (f) an
oil soluble organomolybdenum compound.
6. A composition according to claim 5, wherein said oil soluble
organomolybdenum compound comprises sulfur and is
phosphorus-free.
7. A composition according to claim 6, wherein the weight ratio of
phosphorus to molybdenum is greater than or equal to 1.0.
8. A composition according to claim 6, wherein the weight ratio of
phosphorus to molybdenum is greater than 0.0 and less than 1.0.
9. A composition according to claim 6, wherein the weight ratio of
phosphorus to molybdenum is less than or equal to 1.0.
10. A composition according to claim 4 further comprising: (g) a
hindered phenolic antioxidant with the proviso that said hindered
phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol).
11. A composition according to claim 10 wherein the sum of (b), (c)
and (g) is less than or equal to about 1.5 wt. % of said
composition.
12. A composition according to claim 6 further comprising (g) a
hindered phenolic antioxidant with the proviso that said hindered
phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol).
13. A composition according to claim 12 wherein the sum of (b), (c)
and (g) is less than or equal to about 1.5 wt. % of said
composition.
14. A composition according to claim 4 wherein said oil of
lubricating viscosity comprises up to about 15% by weight of a
Group I baseoil.
15. A composition comprising: (a) a major amount of oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks; (b)
4,4'-methylenebis(2,6-di-tert-butylphenol); (c) an alkylated
diphenylamine; (e) a zinc dialkyldithiophosphate; and (f) an oil
soluble organomolybdenum compound; wherein: the weight ratio of (b)
to (c) is greater than or equal to about 0.5; and said composition
produces less than or equal to about 35 mg of total deposits
according to a ASTM D7097 measurement.
16. A composition according to claim 15 wherein said oil soluble
organomolybdenum compound comprises sulfur and is
phosphorus-free.
17. A composition according to claim 15, wherein the weight ratio
of phosphorus to molybdenum is greater than or equal to 1.0.
18. A composition according to claim 15, wherein the weight ratio
of phosphorus to molybdenum is greater than 0.0 and less than
1.0.
19. A composition according to claim 15, wherein the weight ratio
of phosphorus to molybdenum is less than or equal to 1.0.
20. A composition according to claim 15 further comprising: (d) at
least one component selected from the group consisting of
dispersants and detergents.
21. A composition according to claim 15 further comprising: (g) a
hindered phenolic antioxidant with the proviso that said hindered
phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol).
22. A composition according to claim 21 wherein the sum of (b), (c)
and (g) is less than or equal to about 1.5 wt. % of said
composition.
23. A composition according to claim 21 wherein said composition
produces less than or equal to about 25 mg of total deposits
according to an ASTM D7097 measurement.
24. A composition according to claim 20 further comprising (g) a
hindered phenolic antioxidant with the proviso that said phenolic
antioxidant is not 4,4'-methylenebis(2,6-di-tert-butylphenol).
25. A composition according to claim 24 wherein the sum of (b), (c)
and (g) is less than or equal to about 1.5 wt. % of said
composition.
26. A composition according to claim 24 wherein said composition
produces less than or equal to about 25 mg of total deposits
according to an ASTM D7097 measurement.
27. A composition comprising: (a) a major amount of oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks; (b)
4,4'-methylenebis(2,6-di-tert-butylphenol); and (c) an alkylated
diphenylamine; (d) at least one component selected from the group
consisting of dispersants and detergents; (e) a zinc
dialkyldithiophosphate; (f) an oil soluble organomolybdenum
compound; and (g) a hindered phenolic antioxidant with the proviso
that said hindered phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol); wherein said
composition comprises: about 600 ppm or less of phosphorus derived
from said zinc dialkyldithiophosphate; and about 50-400 ppm of
molybdenum derived from said oil soluble organomolybdenum
compound.
28. A composition according to claim 27, wherein said oil soluble
organomolybdenum compound comprises sulfur and is
phosphorus-free.
29. A composition according to claim 27, wherein the weight ratio
of phosphorus to molybdenum is greater than or equal to 1.0.
30. A composition according to claim 27, wherein the weight ratio
of phosphorus to molybdenum is greater than 0.0 and less than
1.0.
31. A composition according to claim 27, wherein the weight ratio
of phosphorus to molybdenum is less than or equal to 1.0.
32. A composition according to claim 27 wherein said composition
comprises about 550 ppm or less of phosphorus derived from said
zinc dialkyldithiophosphate.
33. A composition according to claim 27 wherein said composition
comprises about 100-250 ppm of molybdenum derived from said oil
soluble organomolybdenum compound.
34. A composition according to claim 27 wherein said composition
comprises about 500 ppm or less of phosphorus derived from said
zinc dialkyldithiophosphate.
35. A composition according to claim 27 wherein said composition
comprises about 250-400 ppm of molybdenum derived from said oil
soluble organomolybdenum compound.
36. An engine oil comprising: (a) a major amount of oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks; (b)
4,4'-methylenebis(2,6-di-tert-butylphenol); (c) 0.2 to 1.0 wt % of
an alkylated diphenylamine; (d) 1.0 to 12.0 wt % of at least one
compound selected from the group consisting of dispersants and
detergents; (e) 200 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; and (f) 50 to 400 ppm of molybdenum derived
from an oil soluble organomolybdenum compound; wherein the weight
ratio of (b) to (c) is greater than or equal to 0.5.
37. An engine oil comprising: (a) a major amount of oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks; (b) 0.1 to
1.5 wt % 4,4'-methylenebis(2,6-di-tert-butylphenol); (c) an
alkylated diphenylamine; (d) 1.0 to 12.0 wt % of at least one
compound selected from the group consisting of dispersants and
detergents; (e) 200 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; and (f) 50 to 400 ppm of molybdenum derived
from an oil soluble organomolybdenum compound; wherein the weight
ratio of (b) to (c) is greater than or equal to 0.5.
38. An engine oil according to claim 37 further comprising: (g) 0.1
to 0.5 wt % of any ester derived from
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid.
39. An engine oil comprising: (a) a major amount of oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks; (b)
4,4'-methylenebis(2,6-di-tert-butylphenol); (c) 0.2 to 1.0 wt % of
an alkylated diphenylamine, and (d) 1.0 to 12.0 wt % of at least
one compound selected from the group consisting of dispersants and
detergents, and (e) 300 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; wherein the weight ratio of (b) to (c) is
greater than or equal to 0.5.
40. An engine oil according to claim 39 further comprising: (g) 0.1
to 0.5 wt % of any ester derived from
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid.
41. An engine oil comprising: (a) a major amount of oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks; (b) 0.1 to
1.5 wt % 4,4'-methylenebis(2,6-di-tert-butylphenol); (c) an
alkylated diphenylamine; (d) 1.0 to 12.0 wt % of at least one
compound selected from the group consisting of dispersants and
detergents, and (e) 300 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; wherein the weight ratio of (b) to (c) is
greater than or equal to 0.5.
42. A method of reducing the amount of total volatile organics
produced by an internal combustion engine upon heating and
oxidation of an engine oil comprising lubricating said engine with
a composition according to claim 1.
43. A method of reducing the amount of deposits in an internal
combustion engine, comprising lubricating said engine with a
composition according to claim 1.
44. A method of reducing the poisoning of the catalyst in an
internal combustion engine emission system comprising lubricating
said engine with a composition according to claim 1.
Description
REFERENCE OF RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent
Application No. 60/665,961 filed Mar. 29, 2005, the disclosure of
which is herein incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The invention generally relates to a low phosphorus
lubricant for an internal combustion engine that provides superior
deposit control while still retaining excellent viscosity
control.
BACKGROUND
[0003] Future engine oil lubricants will be required to have low
levels of phosphorus to protect the emission system, but will also
need to provide broad oxidation protection to the lubricant and
reduced wear and deposits in the engine. This is a difficult task
with existing lubricants because the most effective anti-wear and
antioxidant additives are the phosphorus-containing zinc
dialkyldithiophosphates (ZDDPs). In the past, high levels of ZDDP
were used because ZDDPs were low cost materials and provided
superior anti-wear and oxidation performance. However, in the
future, ZDDP will only be allowed at low levels. In 2004, some
commercial gasoline engine oil specifications allowed a maximum of
800 ppm phosphorus from ZDDP. In future engine oil specifications,
levels of phosphorus may drop below 500 ppm, and possibly lower. It
is well known that ashless antioxidants can replace some of the
oxidation performance lost when levels of ZDDP are reduced.
However, it is also known that higher levels of ashless
antioxidants do not always lead to improved oxidation control. In
fact, modern engine oils generally require the use of two or more
ashless antioxidant types in order to compensate for the oxidative
stability lost by using less ZDDP. In addition, specifications for
deposit control are becoming more demanding. In many cases, modern
and future lubricants will require much higher levels of these
various ashless antioxidants. Levels of conventional ashless
antioxidants in excess of 2.0 wt. % may not be adequate for proper
protection of the lubricant and engine. These high levels of
conventional ashless antioxidants become costly and may also lead
to lubricant deficiencies such as corrosion, rust, and seal
incompatibility. New low cost and low ash antioxidant systems are
needed that are effective at controlling lubricant oxidation and
minimizing engine deposits.
[0004] It has been found in this invention that particular
combinations and ratios of
4,4'-methylenebis(2,6-di-tert-butylphenol) and alkylated
diphenylamines provide unexpectedly superior levels of oxidation
and deposit control in low phosphorus engine oils. This allows for
the use of significantly lower treat levels of ashless
antioxidants. The antioxidant systems of this invention are also
effective at significantly reducing the formation of volatile
organic molecules that are produced upon heating and oxidation of
the lubricant. This effect has significant benefits for the
environment, since a reduction in volatile organic molecules should
contribute to a reduction in emissions.
SUMMARY OF THE INVENTION
[0005] One aspect of the present invention is directed toward a
novel lubricating oil composition for an internal combustion engine
that provides superior deposit control while still retaining
excellent viscosity control. Another aspect of the present
invention is directed to the use of the novel lubricating oil
composition to reduce the amount of deposits in an internal
combustion engine. Yet another aspect of the present invention is
directed to the use of the novel lubricating oil composition to
reduce the poisoning of the catalyst in an internal combustion
engine system.
[0006] One composition of the present invention, a low phosphorus
engine oil comprises 4,4'methylenebis(2,6-di-tert-butylphenol) and
an alkylated diphenylamine; wherein the weight ratio of
4,4'-methylenebis(2,6-di-tert-butylphenol) to the alkylated
diphenylamine is greater than or equal to about 0.5 and the engine
oil produces less than or equal to 35 mg of total deposits
according to a ASTM D7097 measurement.
[0007] Another composition of the present invention comprises:
[0008] (A) a major amount of oil of lubricating viscosity selected
from the group consisting of Group II, Group III, Group IV and
synthetic ester base stocks; [0009] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); [0010] (C) an alkylated
diphenylamine; [0011] (D) at least one component selected from the
group consisting of dispersants and detergents; [0012] (E) zinc
dialkyldithiophosphate;
[0013] optionally (F) an oil soluble organomolybdenum compound,
and
[0014] optionally (G) a hindered phenolic antioxidant, with the
proviso that the hindered phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol);
[0015] wherein the lubricating oil composition contains about 600
ppm or less of phosphorus derived from zinc dialkyldithiophosphate;
and
[0016] the weight ratio of (B) to (C) is greater than or equal to
about 0.5.
[0017] Another composition of the present invention comprises:
[0018] (A) a major amount of oil of lubricating viscosity selected
from the group consisting of Group II, Group III, Group IV and
synthetic ester base stocks; [0019] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); [0020] (C) an alkylated
diphenylamine; [0021] (E) a zinc dialkyldithiophosphate; and [0022]
(F) an oil soluble organomolybdenum compound; and
[0023] optionally (G) a hindered phenolic antioxidant, with the
proviso that the hindered phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol);
wherein:
[0024] the weight ratio of (B) to (C) is greater than or equal to
about 0.5; and
[0025] the composition produces less than or equal to about 35 mg
of total deposits according to an ASTM D7097 measurement.
[0026] Yet another composition of the present invention comprises:
[0027] (A) a major amount of oil of lubricating viscosity selected
from the group consisting of Group II, Group III, Group IV and
synthetic ester base stocks; [0028] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); [0029] (C) an alkylated
diphenylamine; [0030] (D) at least one component selected from the
group consisting of dispersants and detergents; [0031] (E) zinc
dialkyldithiophosphate; [0032] (F) an oil soluble organomolybdenum
compound, and [0033] (G) a hindered phenolic antioxidant, with the
proviso that the hindered phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol);
[0034] wherein the composition comprises:
[0035] about 600 ppm or less of phosphorus derived from zinc
dialkyldithiophosphate; and
[0036] about 50-400 ppm of molybdenum derived from the oil soluble
organomolybdenum compound.
[0037] Yet another composition of the present invention is an
engine oil lubricating composition comprising: [0038] (A) a major
amount of oil of lubricating viscosity selected from the group
consisting of Group II, Group III, Group IV and synthetic ester
base stocks; [0039] (B) 4,4'-methylenebis(2,6-di-tert-butylphenol);
[0040] (C) 0.2 to 1.0 wt % of an alkylated diphenylamine; [0041]
(E) 200 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; and [0042] (F) 50 to 400 ppm of molybdenum
derived from an oil soluble organomolybdenum compound; wherein the
weight ratio of (b) to (c) is greater than or equal to 0.5.
[0043] Yet another composition of the present invention is an
engine oil lubricating composition comprising: [0044] (A) a major
amount of oil of lubricating viscosity selected from the group
consisting of Group II, Group III, Group IV and synthetic ester
base stocks; [0045] (B) 0.1 to 1.5 wt %
4,4'-methylenebis(2,6-di-tert-butylphenol); [0046] (C) an alkylated
diphenylamine; [0047] (D) 1.0 to 12.0 wt % of at least one compound
selected from the group consisting of dispersants and detergents;
[0048] (E) 200 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; and [0049] (F) 50 to 400 ppm of molybdenum
derived from an oil soluble organomolybdenum compound; wherein the
weight ratio of (b) to (c) is greater than or equal to 0.5.
[0050] Another composition of the present invention is an engine
oil lubricating composition comprising: [0051] (A) a major amount
of oil of lubricating viscosity selected from the group consisting
of Group II, Group III, Group IV and synthetic ester base stocks;
[0052] (B) 4,4'-methylenebis(2,6-di-tert-butylphenol); [0053] (C)
0.2 to 1.0 wt % of an alkylated diphenylamine, and [0054] (D) 300
to 600 ppm of phosphorus derived from zinc dialkyldithiophosphate;
wherein the weight ratio of (b) to (c) is greater than or equal to
0.5.
[0055] Yet another composition of the present invention is an
engine oil lubricating composition comprising: [0056] (A) a major
amount of oil of lubricating viscosity selected from the group
consisting of Group II, Group III, Group IV and synthetic ester
base stocks; [0057] (B) 0.1 to 1.5 wt %
4,4'-methylenebis(2,6-di-tert-butylphenol); [0058] (C) an alkylated
diphenylamine; [0059] (D) 1.0 to 12.0 wt % of at least one compound
selected from the group consisting of dispersants and detergents,
and [0060] (E) 300 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; wherein the weight ratio of (b) to (c) is
greater than or equal to 0.5.
[0061] By "a major amount" it is meant an amount greater than 50 wt
% based on the total weight of the composition.
BRIEF DESCRIPTION OF THE FIGURES
[0062] FIG. 1 is a graph of the deposit results obtained from ASTM
D7097 (TEOST MHT-4) in the absence of MoDTC (molybdenum
bis(dialkyldithiocarbamate) containing 4.5 wt. % molybdenum).
[0063] FIG. 2 is a graph of the deposit results obtained from ASTM
D7097 (TEOST MHT-4) in the presence of MoDTC.
DETAILED DESCRIPTION OF THE INVENTION
I. Definitions
[0064] ASTM D7097 is the "Standard Test Method for Determination of
Moderately High Temperature Piston Deposits by Thermo-oxidation
Engine Oil Simulation Tests," approved December 2004, which is
incorporated by reference in its entirety for any purpose. ASTM
D7097 is a new standard lubricant industry test for the evaluation
of the oxidation and carbonaceous deposit-forming characteristics
of engine oils. The test is designed to simulate high temperature
deposit formation in the piston ring belt area of modern engines.
Details of the test operation and specific conditions for various
protocols are further reported in the following publications, all
of which are incorporated by reference in their entirety for any
purpose: [0065] Selby and Florkowski, "The Development of the TEOST
Protocol MHT as a Bench Test of Engine Oil Piston Deposit Tendency"
in Proceedings 12th International Colloquium Tribology, TAE,
Ostfildern, Germany, Jan. 11-13, 2000, Supplement, pp 55-62. [0066]
Selby, Richardson and Florkowski, "Engine Oil Deposits and the
TEOST--Protocol 33 and Beyond" SAE Technical Paper Series, 962039,
from International Fall Fuels & Lubricants Meeting and
Exposition, San Antonio, Tex., Oct. 14-17, 1996. [0067] Selby,
"Recent Developments in Testing Lubricants" 6th International LFE
Congress, Brussels, Belgium, Jun. 2-4, 1999.
[0068] The test is also a useful tool for studying the formation of
volatile organic molecules upon oxidation of an engine oil. It is
generally understood that the formation of volatile organic
molecules upon oxidation of a lubricant are detrimental because
they lead to an increase in emissions, and can also promote further
polymerization of the lubricant. Polymerization of the lubricant
leads to viscosity increase, which is also undesirable. The
additive combination of this invention is effective at controlling
both deposit formation and the formation of volatile organic
molecules. Typically, polar volatile organic molecules are formed
by decomposition of an organic peroxide in the lubricant. This
decomposition produces an organic alkoxy radical that can react
with another oil molecule to produce an alcohol, or that can
degrade to form aldehydes and ketones. The degradation to aldehydes
and ketones generally reduces molecular weight and thus produces
more volatile fragments, which are pollutants and are also active
precursors to oligomers and polymers that thicken the lubricant. It
is therefore highly desirable to prevent or eliminate the formation
of these polar volatile organic molecules.
[0069] A "low phosphorus engine oil," as used herein, refers to an
engine oil that contains less than about 600 ppm of phosphorus
derived from zinc dialkyldithiophosphate.
[0070] "Hydrocarbyl" as used herein refers to any alkyl, alkenyl,
or alkynyl group, which can be linear, cyclic or any combination
thereof, wherein each group is optionally substituted. Such
substituents may include reactive groups, including but not limited
to succinic groups.
[0071] The term "about" as used herein means including and
exceeding up to 20% the specific endpoint(s) designated. Thus the
range is broadened, for example "about 1" is intended to include
the range 0.8 to 1.2.
[0072] Organic friction modifiers are molecules containing long
non-polar hydrocarbon chains possessing a polar end-group that has
affinity for the metal engine surface. An "organic friction
modifier," as used herein includes but is not limited to long chain
organic fatty or carboxylic acids, esters, ethers, amines, imides,
amides, sulfurized fatty acids, metallo-organic compounds, high
molecular weight organic phosphorus and phosphoric acid esters.
Examples of other conventional organic friction modifiers are
described in R. Hoogendoorn and D. Kenbeek, "Friction Modifiers to
the Rescue" in Lubes-n-Greases (2003), Vol. 9, Issue 11, pp. 14-20,
which is incorporated by reference in its entirety for any purpose.
Organic friction modifiers are typically used between 0 and 1.0 wt.
% in fully formulated engine oils.
[0073] A "corrosion inhibitor" as used herein includes but is not
limited to thiadiazole polysulfides containing from 5 to 50 carbon
atoms, their derivatives and polymers thereof. Typical corrosion
inhibitors are disclosed in Hamblin, et al., "Ashless Antioxidants,
Copper Deactivators and Corrosion Inhibitors: their Use in
Lubricating Oils" Lubrication Science (1990), 2(4), pp. 287-318.
Suitable corrosion inhibitors include derivatives of 1,3,4
thiadiazoles such as polysulfide derivatives of
2,5-dimercapto-1,3,4-thiadiazole (1,3,4-thiadiazole polysulfide)
having the general formula: ##STR1## wherein R.sup.1 and R.sup.2
are the same or different hydrocarbon radicals and can be aliphatic
or aromatic, including alkyl, aralkyl, aryl and alkaryl radicals, x
and y are 0 to about 8, the sum of x and y is at least 1, and in
some embodiments between 2 and 16. Methods of preparing such
compounds are disclosed in U.S. Patent Nos. 2,719,125, 2,719,126,
and 3,087,932 which are each incorporated by reference in its
entirety for any purpose. Other similar materials are described in
U.S. Patent Nos. 3,821,236; 3,904,537; 4,097,387; 4,107,059;
4,136,043; 4,188,299; and 4,193,882. Other corrosion inhibitors are
the thio and polythio sulfenamides of thiadiazoles such as those of
the general formulae: ##STR2## wherein z is from 2 to 5 and R.sup.3
is hydrogen, a hydrocarbyl group, another sulphenamide or
thiosulphenamide group, R.sup.4 and R.sup.5 can be hydrogen or
hydrogen and carbon containing groups, provided R.sup.4 and R.sup.5
are not both hydrogen or R.sup.4 and R.sup.5 form a heterocyclic
ring with the nitrogen to which they are attached, as described in
UK Patent Specification No. 1,560,830. All of the cited references
are incorporated by reference herein in their entirety for any
purpose. Benzotriazoles derivatives also fall within this class of
additives. Other examples of corrosion inhibitors include dodecenyl
succinic acids, esters, amides, and mixed ester/amides, fatty
amines, linear alkyl amines, fatty acids, linear carboxylic acids,
some branched alkyl amines, some branched carboxylic acids, sulfur
and phosphorus compounds and some detergents. Corrosion inhibitors
are typically used between 0 and 0.5 wt. % in a fully formulated
engine oil.
[0074] A "viscosity modifier," as used herein includes those
modifiers which function to impart high and low temperature
operability to a lubricating oil. Such modifiers include, but are
not limited to polyisobutylene, copolymers of ethylene and
propylene and higher alpha-olefins, polymethacrylates,
polyalkylmethacrylates, methacrylate copolymers, copolymers of an
unsaturated dicarboxylic acid and a vinyl compound, inter polymers
of styrene and acrylic esters, and partially hydrogenated
copolymers of styrene/isoprene, styrene/butadiene, and
isoprene/butadiene, as well as the partially hydrogenated
homopolymers of butadiene and isoprene and isoprene/divinylbenzene.
Typical viscosity modifiers are polymers having a molecular weight
ranging from 20,000 to 1,000,000. Typical viscosity modifiers are
disclosed in M. K. Mishra and R. G. Saxton, "Polymer Additives For
Engine Oils" CHEMTECH, April 1995, pp. 35-41, which is incorporated
by reference herein for any purpose.
[0075] Pour point depressants are molecules that are added to an
oil that interfere with and alter wax crystal growth at low
temperatures. A "pour point depressant," as used herein includes
those depressants which function to lower the minimum temperature
at which the fluid will flow or can be poured. Such depressants
include, but are not limited to C.sub.8 to C.sub.18 dialkyl
fumarate/vinyl acetate copolymers, polyalkylmethacrylates and the
like. Typical pour point depressants are disclosed in Mishra and
Saxton, CHEMTECH, April 1995, pp. 35-41.
[0076] A "phosphorus-free anti-wear additive," as used herein
refers to any phosphorus-free compound that reduces wear in an
engine, an engine test, or a bench wear test, when added to a fully
formulated engine oil. Examples of phosphorus-free anti-wear
additives include sulfurized olefins, sulfurized fatty acids and
oils, sulfurized fatty esters, sulfurized mixed fatty acid/fatty
esters, sulfurized mixed fatty acid/olefins, sulfurized mixed fatty
esters/fatty acids, organic sulfides, disulfides, trisulfides and
polysulfides, thiocarbamates, thiuram sulfides, disulfides,
trisulfides and polysulfides, molybdenum dithiocarbamates, zinc
dithiocarbamates, molybdenum amine complexes, molybdenum alcohol
complexes, mixed molybdenum amine/molybdenum alcohol complexes, and
molybdenum carboxylates.
[0077] A "fully formulated engine oil" as used herein may contain
additional, typical additives known to those skilled in the
industry, and is used as an engine oil in an as-received basis.
II. Components of the Invention
Component (A)
[0078] Component (A) may be any combination of an oil of
lubricating viscosity selected from the group consisting of Group
II, Group III, Group IV and synthetic ester base stocks. Component
(A) may further include up to about 15% by weight of a Group I
basestock. The various basestock groups are identified chemically
and physically in the American Petroleum Institute (API)
publication Engine Oil Licensing and Certification System, Industry
Services Department, 14.sup.th Ed. (December 1996) Addendum 1
(December 1998), which is hereby incorporated by reference in its
entirety for any purpose. In one embodiment of the invention, the
base stock has a viscosity of 3-12 mm.sup.2/s (cSt) at 100.degree.
C.; in another embodiment, the base stock has a viscosity of 4-10
mm.sup.2/s (cSt) at 100.degree. C.; and in yet another embodiment,
the base stock has a viscosity of 4.5-8 mm.sup.2/s (cSt) at
100.degree. C.
[0079] Group II mineral oil base stocks contain greater than or
equal to 90 wt % saturates and less than or equal to 0.03 wt %
sulfur and have a viscosity index greater than or equal to 80 and
less than 120 using the test methods specified in Table 1 below. In
one embodiment, Group II basestocks contain greater than or equal
to 95 wt % saturates and less than or equal to 0.01 wt % sulfur and
have a viscosity index greater than or equal to 100 and less than
120 using the test methods specified in Table 1 below.
[0080] Group III mineral oil base stocks contain greater than or
equal to 90 wt % saturates and less than or equal to 0.03 wt %
sulfur and have a viscosity index greater than or equal to 120
using the test methods specified in Table 1 below. In one
embodiment, Group III basestocks contain greater than or equal to
98 wt % saturates and less than or equal to 0.01 wt % sulfur and
have a viscosity index greater than or equal to 130 using the test
methods specified in Table 1 below.
[0081] Group IV base stocks are poly-.alpha.-olefins.
[0082] Suitable ester base stocks that can be used include the
esters of dicarboxylic acids (e.g. phthalic acid, succinic acid,
alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic
acid, suberic acid, sebacic acid, fumaric acid, adipic acid,
linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl
malonic acids, etc.) with a variety of alcohols (e.g. butyl
alcohol, hexyl alcohol, dodecyl alcohol 2-ethylhexyl alcohol,
ethylene glycol, diethylene glycol monoether, propylene glycol,
etc.). Specific examples of these esters include dibutyl adipate,
bis(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate,
di-isooctyl azelate, di-isodecyl azelate, dioctyl phthalate,
didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of
linoleic acid dimer, the complex ester formed by reacting one mole
of sebacic acid with two moles of tetraethylene glycol and two
moles of 2-ethylhexanoic acid and the like.
[0083] Esters useful as base stock oils also include those made
from C.sub.5-C.sub.12 monocarboxylic acids and polyols and polyol
ethers, such as neopentyl glycol, trimethylol propane,
pentaerythritol, dipentaerythritol, tripentaerythritol, etc.
TABLE-US-00001 TABLE 1 Analytical Methods for Testing Base Stocks
Property Test Method Saturates ASTM D2007 Viscosity Index ASTM
D2270 Sulfur ASTM D2622, D4292, D4927 or D3120
[0084] Component A comprises from about 75 to 97 wt % of the
composition based on the total weight of the composition. Most
preferably Component A will comprise from about 80 to 95 wt %.
Component (B)
[0085] The chemical structure of
4,4'-methylenebis(2,6-di-tert-butylphenol), a hindered phenolic
antioxidant, is depicted below: ##STR3##
[0086] In one embodiment of the invention,
4,4'-methylenebis(2,6-di-tert-butylphenol) is used between about
0.1 and about 1.5 wt. % in a fully formulated engine oil.
Component (C)
[0087] Alkylated diphenylamine (component C) has the general
formula: R.sub.a--NH--R.sub.b, wherein R.sub.a and R.sub.b each
independently represents a substituted or unsubstituted phenyl
group. Substituents on the phenyl rings may include but are not
limited to alkyl groups having from 1 to 20 carbon atoms, alkylaryl
groups, hydroxy, carboxy and nitro groups. In one embodiment of the
invention, one or both of the phenyl groups are substituted with an
alkyl. In yet another embodiment of the invention, both phenyl
groups are alkyl substituted.
[0088] Examples of alkylated diphenylamines which can be used in
the present invention include 3-hydroxydiphenylamine,
N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine,
butyldiphenylamine, dibutyldiphenylamine, octyldiphenylamine,
dioctyldiphenylamine, nonyldiphenylamine, dinonyldiphenylamine,
heptyldiphenylamine, diheptyldiphenylamine,
methylstyryldiphenylamine, mixed butyl/octyl alkylated
diphenylamines, mixed butyl/styryl alkylated diphenylamines, mixed
ethyl/nonyl alkylated diphenylamines, mixed octyl/styryl alkylated
diphenylamines, mixed ethyl/methylstyryl alkylated diphenylamines,
and combinations of these of varying degrees of purity that are
commonly used in the petroleum industry.
[0089] In one embodiment of the invention, the nitrogen content of
the alkylated diphenylamines ranges from about 2 wt % to about 12
wt % of the alkylated diphenylamine. The concentration of the
alkylated diphenylamine in the fully formulated oil can vary
depending on customers' requirements and applications, and the
desired level of antioxidant protection required for the specific
composition of this invention. In one embodiment of the invention,
the alkylated diphenylamines are present in the compositions of
this invention in an amount from about 0.05 wt % to about 1.0 wt %
of the composition weight; in another embodiment in an amount from
about 0.1 wt % to about 0.75 wt %; in yet another embodiment, the
alkylated diphenylamines are present in an amount from about 0.2 wt
% to about 1.0 wt %.
Component (D)
[0090] The composition further comprises any dispersant and/or
detergent (component D) used in engine oils and known in the art.
In one embodiment of the invention either a detergent or dispersant
is present in the fully formulated engine oil formulation. In
another embodiment, both a detergent and a dispersant are present
in the fully formulated engine oil formulation. Either the
dispersant or the detergent may be boronated, or borated.
[0091] Dispersants are well known in the field of lubricants and
include primarily what are sometimes referred to as "ashless"
dispersants because (prior to mixing in a lubricating composition)
they do not contain ash-forming metals and they do not normally
contribute any ash-forming metals when added to a lubricant.
[0092] Dispersants typically are nonmetallic additives containing
nitrogen or oxygen polar groups attached to a high molecular weight
hydrocarbon chain. The hydrocarbon chain provides solubility in the
hydrocarbon base stocks. The dispersants function to keep oil
degradation products suspended in the oil. Examples of suitable
dispersants include but are not limited to polymethacrylates,
styrene-maleic ester copolymers, substituted succinimides (e.g.,
PIBSA (polyisobutylene succinic anhydride)), polyamine
succinimides, polyhydroxy succinic esters, substituted Mannich
bases, and substituted triazoles.
[0093] The dispersants may be borated. Borated dispersants are
well-known materials and can be prepared by treatment with a
borating agent such as boric acid. Typical conditions include
heating the dispersant with boric acid at about 100 to 150.degree.
C. The dispersants may also be treated by reaction with maleic
anhydride; for example, a succinimide dispersant can be prepared by
the reaction of an amount of an .alpha.,.beta.,-unsaturated acid or
equivalent thereof, such as maleic anhydride, with an amount of an
amine with a hydrocarbyl-substituted acylating agent characterized
by the presence of at least 1.3 succinic groups for each equivalent
weight of substituent group, wherein the reaction of the acid can
be simultaneous with or subsequent to the reaction of the amine and
the hydrocarbyl-substituted acylating agent, as described in WO
00/26327, filed Oct. 13, 1999, which is incorporated herein by
reference in its entirety for any purpose.
[0094] In one embodiment of the invention, the amount of dispersant
in the composition of this invention range from about 0.5 wt. % to
about 10 wt. % based on the total composition weight. In another
embodiment of the invention, the amount of dispersant in the
compositions of the invention range from about 1.0 wt. % to about
12.0 wt. %; in yet another embodiment the amount ranges from about
1.0 wt. % to about 8.0 wt. %. In another embodiment of the
invention, the amount of dispersant in the composition of this
invention range from about 3.0 wt. % to about 7.0 wt. %. Its
concentration in a concentrate will be correspondingly increased
to, e.g., from about 5 wt. % to about 90 wt. %.
[0095] Detergents are generally salts of organic acids, which are
often overbased. Metal overbased salts of organic acids are widely
known to those of skill in the art and generally include metal
salts wherein the amount of metal present exceeds the
stoichiometric amount. Detergents are typically metallic additives
containing metal ions and polar groups, such as sulfonates or
carboxylates, with aliphatic, cycloaliphatic or alkylaromatic
chains. The detergents function by lifting deposits from the
various surfaces of the engine. Suitable detergents include neutral
and overbased alkali and alkaline earth metal sulfonates, neutral
and overbased alkali and alkaline earth metal phenates, sulfuirized
phenates, and overbased alkaline earth salicylates. Patents
describing techniques for making detergents generally include U.S.
Pat. Nos. 2,501,731; 2,616,905; 2,616,911; 2,616,925; 2,777,874;
3,256,186; 3,384,585; 3,365,396; 3,320,162; 3,318,809; 3,488,284;
and 3,629,109, all of which are hereby incorporated by reference
for any purpose.
[0096] The detergents generally can be borated by treatment with a
borating agent such as boric acid. Typical conditions include
heating the detergent with boric acid at about 100 to 150.degree.
C., the number of equivalents of boric acid being roughly equal to
the number of equivalents of metal in the salt. U.S. Pat. No.
3,929,650 discloses borated complexes prepared by contacting boric
acid with an alkali metal carbonate overbased metal sulfonate
(prepared by overbasing a neutral alkali or alkaline earth metal
sulfonate with an alkali metal carbonate) in an oleophilic liquid
reaction medium and is incorporated herein by reference in its
entirety for any purpose.
[0097] In one embodiment of the invention, the amount of detergent
in a composition of this invention ranges from about 0.5 wt. % to
about 5 wt. % based on the total weight of the composition. In
another embodiment of the invention, the amount of detergent in a
composition of the invention ranges from about 1.0 wt. % to about
6.0 wt. %; in yet another embodiment, the amount ranges from about
1.0 wt. % to about 4.0 wt. %. In another embodiment of the
invention, the amount of detergent in a composition of this
invention ranges from about 1.0 wt. % to about 3.0 wt. %. Its
concentration in a concentrate will be correspondingly increased,
to, e.g., about 5 wt. % to about 70 wt. %.
Component (E)
[0098] The zinc dialkyldithiophosphate (ZDDP) (component E) in the
oil composition may be any ZDDP derived from the reaction of an
alcohol or phenol and phosphorus pentasulfide (P.sub.2S.sub.5) to
produce a dialkyldithiophosphoric acid derivative (DDPA) followed
by neutralization with a basic zinc compound.
[0099] Zinc salts (M=Zn) of the formula: ##STR4## wherein R.sup.8
and R.sup.9 are independently hydrocarbyl groups containing 3 to 30
carbon atoms are readily obtainable by the reaction of
(P.sub.2S.sub.5) and an alcohol or phenol to form an
O,O-dihydrocarbyl phosphorodithioic acid of the formula: ##STR5##
The reaction involves mixing at a temperature of 20.degree. C. to
200.degree. C., four moles of an alcohol or a phenol with one mole
of phosphorus pentasulfide. Hydrogen sulfide is liberated in this
reaction. The acid is then reacted with a basic zinc compound to
form the salt. In one embodiment of the invention, the basic zinc
compound is zinc oxide (ZnO) and the resulting zinc compound is
represented by the formula: ##STR6## The R.sup.8 and R.sup.9 groups
are independently hydrocarbyl groups that are, in one embodiment of
the invention, free from acetylenic unsaturation. In another
embodiment, R.sup.8 and R.sup.9 are free from ethylenic
unsaturation and in yet another embodiment, R.sup.8 and R.sup.9 are
free from both acetylenic and ethylenic unsaturation. In one
embodiment, R.sup.8 and R.sup.9 are alkyl, cycloalkyl, aralkyl or
alkaryl groups and have 3 to 20 carbon atoms; in another embodiment
they have 3 to 16 carbon atoms and in yet another embodiment up to
13 carbon atoms, e.g., 3 to 13 carbon atoms. The alcohols which
react to provide the R.sup.8 and R.sup.9 groups can be one or more
primary alcohols, one or more secondary alcohols, or a mixture of
secondary alcohol and primary alcohol. A mixture of two secondary
alcohols such as isopropanol and 4-methyl-2-pentanol also can be
used.
[0100] Such materials are often referred to as zinc
dialkyldithiophosphates or simply zinc dithiophosphates. They are
well known and readily available to those skilled in the art of
lubricant forrnulation.
[0101] In one embodiment of the invention, the level of ZDDP
delivers less than about 600 ppm of phosphorus to the compositions
of this invention; in one embodiment between about 200 and about
600 ppm of phosphorus is delivered; in yet another embodiment,
between about 300 and about 600 ppm is delivered. The "ppm" is
based on the total weight of the composition. In another
embodiment, the level of ZDDP delivers less than about 550 ppm of
phosphorus to the compositions of this invention. For example, a
ZDDP containing 8.5 wt. % phosphorus would be used at a level less
than 0.65 wt. % in the compositions of this invention. In yet
another embodiment, the level of ZDDP delivers less than about 500
ppm of phosphorus to the compositions of this invention.
Component (F)
[0102] Any oil soluble organomolybdenum compound (component F) may
be used as an optional component in the lubricating compositions of
the present invention. The quantity of molybdenum delivered to the
compositions of this invention will vary depending upon the
customers' requirements and applications, and the desired level of
antioxidant protection required for the specific composition of
this invention. Any concentration of oil soluble organomolybdenum
may be used, but in one embodiment, the level is less than about
600 ppm. In another embodiment, the level is less than about 500
ppm. In yet another embodiment, the level is about 50-400 ppm. In
another embodiment, the molybdenum level is about 100-250 ppm. In
yet another embodiment, the level of molybdenum metal is about
250-400 ppm. The "ppm" is based on the total weight of the
composition.
[0103] In general, molybdenum is an effective antioxidant in
lubricating oil compositions; however, the use of molybdenum in the
compositions of this invention need to be balanced against the cost
of oil soluble organomolybdenum compounds compared to other
antioxidants, such as ZDDP.
[0104] Examples of some oil soluble organomolybdenum compounds that
may be used in this invention include molybdenum dithiocarbamates,
oxymolybdenum sulfide dithiocarbamates, molybdenum
dithioxanthogenates, oxymolybdenum sulfide dithioxanthogenates,
molybdenum organophosphorodithioates, oxymolybdenum sulfide
organophosphorodithioates, molybdenum carboxylates, molybdenum
amine complexes, molybdenum alcohol complexes, molybdenum amide
complexes, mixed molybdenum amine/alcohol/amide complexes, and
combinations of these. In one embodiment of the invention the
molybdenum compound is a sulfur-containing and phosphorus-free
compound.
Component (G)
[0105] Component (G) may be any hindered phenolic antioxidant other
than 4,4'-methylenebis(2,6-di-tert-butylphenol). Component (G) may
be for example: 2,6-di-tert-butylphenol;
2,6-di-tert-butyl-4-methylphenol;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid, isooctyl ester;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid,
C.sub.7-C.sub.9-branched alkyl esters;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid, n-octadecyl ester;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid, n-butyl ester;
2,4,6-tri-tert-butylphenol; 2,4-di-tert-butylphenol;
4,4'-thiobis(2,6-di-tert-butylphenol);
4,4'-dithiobis(2,6-di-tert-butylphenol);
4,4'-polythiobis(2,6-di-tert-butylphenol);
2,2'-thiobis(4,6-di-tert-butylphenol);
2,2'-dithiobis(4,6-di-tert-butylphenol);
2,2'-polythiobis(4,6-di-tert-butylphenol);
4,4'-ethylidenebis(2,6-di-tert-butylphenol);
4,4'-butylidenebis(2,6-di-tert-butylphenol);
2,2'-methylenebis(4,6-di-tert-butylphenol);
2,2'-ethylidenebis(4,6-di-tert-butylphenol);
2,2'-butylidenebis(4,6-di-tert-butylphenol);
4,4'-thiobis(2-methyl-6-tert-butylphenol);
4,4'-dithiobis(2-methyl-6-tert-butylphenol);
4,4'-polythiobis(2-methyl-6-tert-butylphenol);
2,2'-thiobis(4-methyl-6-tert-butylphenol);
2,2'-dithiobis(4-methyl-6-tert-butylphenol);
2,2'-polythiobis(4-methyl-6-tert-butylphenol);
4,4'-ethylidenebis(2-methyl-6-tert-butylphenol);
4,4'-butylidenebis(2-methyl-6-tert-butylphenol);
2,2'-methylenebis(4-methyl-6-tert-butylphenol);
2,2'-ethylidenebis(4-methyl-6-tert-butylphenol);
2,2'-butylidenebis(4-methyl-6-tert-butylphenol);
4,4'-methylenebis(2-methyl-6-tert-butylphenol); octylphenol;
nonylphenol; dodecylphenol; thiobis(octylphenol);
thiobis(nonylphenol); thiobis(dodecylphenol);
dithiobis(octylphenol); dithiobis(nonylphenol);
dithiobis(dodecylphenol); polythiobis(octylphenol);
polythiobis(nonylphenol); polythiobis(dodecylphenol);
methylenebis(octylphenol); methylenebis(nonylphenol);
methylenebis(dodecylphenol); ethylidenebis(octylphenol);
ethylidenebis(nonylphenol); ethylidenebis(dodecylphenol);
butylidenebis(octylphenol); butylidenebis(nonylphenol);
butylidenebis(dodecylphenol);
.alpha.,.alpha.'-thiobis(2,6-di-tert-butyl-p-cresol);
.alpha.,.alpha.'-thiobis(2-methyl-6-tert-butyl-p-cresol);
2,6-di-tert-butyl-4-ethylphenol; 2,6-di-tert-butyl-4-butylphenol;
2,6-di-tert-butyl-4-octylphenol
2,6-di-tert-butyl-4-isoheptylphenol;
2,6-di-tert-butyl-4-isooctylphenol;
2,6-di-tert-butyl-4-(2-ethylhexyl)phenol;
2,6-di-tert-butyl-4-isononylphenol; 2,6-di-tert-butyl-4-nonylphenol
2,6-di-tert-butyl-4-isodecylphenol;
2,6-di-tert-butyl-4-isododecylphenol;
2,6-di-tert-butyl-4-dodecylphenol;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid, isoheptyl ester;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid, isononyl ester;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid, isodecyl ester;
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid, isododecyl ester; or
non-volatile multi-ring (or methylene bridged) tert-butylphenolics
as defined below: ##STR7## where X can vary from 1 to 5, and R is
hydrogen or tert-butyl, or as defined in any one of U.S. Pat. No.
3,211,652, wherein for example, R can be a hydrogen or an alkyl
group having from 4 to about 9 carbon atoms, U.S. Patent
Application 2002/0142923, and U.S. Pat. No. 2,807,653, wherein for
example, R can be hydrogen or a hydrocarbon radical containing up
to about 9 carbon atoms. Each of the cited references is hereby
incorporated by reference in its entirety for any purpose.
[0106] In one embodiment of the invention, the hindered phenolic
antioxidant contains sulfur. In another embodiment of the
invention, the hindered phenolic antioxidant is sulfur-free.
[0107] In one embodiment of the invention, the amount of hindered
phenolic antioxidant other than
4,4'-methylenebis(2,6-di-tert-butylphenol) is present in the
composition of this invention in an amount between about 0.1 wt. %
and about 0.75 wt. %; in another embodiment it is present in an
amount between about 0.1 wt. % and about 0.5 wt. %, all wt % being
based on the total weight of the composition.
III. OTHER EMBODIMENTS OF THE INVENTION
[0108] This invention provides a lubricating oil composition
capable of providing improved deposit control to an internal
combustion engine.
[0109] In one aspect of the invention, a low phosphorus engine oil
composition comprises: 4,4'-methylenebis(2,6-di-tert-butylphenol)
and an alkylated diphenylamine; wherein the weight ratio of
4,4'-methylenebis(2,6-di-tert-butylphenol) to the alkylated
diphenylamine is greater than or equal to about 0.5 and the engine
oil produces less than or equal to 35 mg of total deposits
according to a ASTM D7097 measurement. In one embodiment, the
composition further comprises a zinc dialkyldithiophosphate;
wherein the engine oil comprises about 600 ppm or less of
phosphorus derived from the zinc dialkyldithiophosphate. In another
embodiment, the composition further comprises an oil soluble
organomolybdenum compound. Engine oils include formulated oils used
in gasoline, diesel, natural gas and railroad engines.
[0110] In one aspect of the invention, the engine oil comprises:
[0111] (A) a major amount of oil of lubricating viscosity selected
from the group consisting of Group II, Group III, Group IV and
synthetic ester base stocks; [0112] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); [0113] (C) an alkylated
diphenylamine; [0114] (D) at least one component selected from the
group consisting of dispersants and detergents; and [0115] (E) a
zinc dialkyldithiophosphate (ZDDP); wherein the composition
comprises about 600 ppm or less of phosphorus derived from zinc
dialkyldithiophosphate (ZDDP); and the weight ratio of (B) to (C)
is greater than or equal to about 0.5.
[0116] In another embodiment of the invention the composition
further comprises an oil soluble organomolybdenum compound. In yet
another embodiment, the oil soluble organomolybdenum compound
comprises sulfur and is phosphorus-free. In one embodiment of the
invention, the weight ratio of phosphorus to molybdenum in the
composition is greater than or equal to 1.0. In another embodiment,
the weight ratio of phosphorus to molybdenum is greater than 0.0
and less than 1.0. In yet another embodiment of the invention, the
weight ratio of phosphorus to molybdenum is less than or equal to
1.0. In another embodiment of the invention, the compositions can
contain (G) a hindered phenolic antioxidant, with the proviso that
the hindered phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol). In another embodiment
of the invention, the sum of (B), (C) and (G) is less than or equal
to about 1.5 wt. % of the composition. In another embodiment of the
invention, the oil of lubricating viscosity (component (A))
comprises up to about 15% by weight (based on the weight of
component A) of a Group I baseoil. A further embodiment is a
lubricating oil composition described above, wherein the
composition produces less than or equal to about 35 mg of total
deposits according to an ASTM D7097 measurement; in another
embodiment, the composition produces less than or equal to about 25
mg of total deposits according to an ASTM D7097 measurement; and in
yet another embodiment, the composition produces less than or equal
to about 15 mg of total deposits.
[0117] In another aspect of the invention, the engine oil
comprises: [0118] (A) a major amount of oil of lubricating
viscosity selected from the group consisting of Group II, Group
III, Group IV and synthetic ester base stocks; [0119] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); and [0120] (C) an
alkylated diphenylamine; [0121] (E) a zinc dialkyldithiophosphate;
and [0122] (F) an oil soluble organomolybdenum compound; wherein
the weight ratio of (B) to (C) is greater than or equal to about
0.5; and the composition produces less than or equal to about 35 mg
of total deposits according to an ASTM D7097 measurement.
[0123] In one embodiment of the invention, the oil soluble
organomolybdenum compound comprises sulfur and is phosphorus-free.
In one embodiment, the weight ratio of phosphorus to molybdenum is
greater than or equal to 1.0; in another embodiment the weight
ratio is greater than 0.0 and less than 1.0. In yet another
embodiment of the invention, the weight ratio of phosphorus to
molybdenum is less than or equal to 1.0. In another embodiment of
the invention, the composition further comprises at least one
component selected from the group consisting of dispersants and
detergents. In another embodiment of the invention, the engine oil
further comprises (G) a hindered phenolic antioxidant, with the
proviso that the hindered phenolic antioxidant is not
4,4'-methylenebis(2,6-di-tert-butylphenol). In yet another
embodiment, the sum of (B), (C) and (G) is less than or equal to
about 1.5 wt. % of the composition. In a further embodiment of the
invention, such compositions produce less than or equal to about 25
mg of total deposits according to an ASTM D7097 measurement. In yet
another embodiment of the invention, the engine oil further
comprises (D) at least one component selected from the group
consisting of dispersants and detergents and (G) a hindered
phenolic antioxidant, with the proviso that the hindered phenolic
antioxidant is not 4,4'-methylenebis(2,6-di-tert-butylphenol). In
yet another embodiment, the sum of (B), (C) and (G) is less than or
equal to about 1.5 wt. % of the engine oil. In a further embodiment
of the invention, this engine oil produces less than or equal to
about 25 mg of total deposits according to an ASTM D7097
measurement. A further embodiment is an engine oil described above,
wherein the engine oil produces less than or equal to 15 mg of
total deposits according to an ASTM D7097 measurement.
[0124] In yet another aspect of the invention, the engine oil
comprises: [0125] (A) a major amount of oil of lubricating
viscosity selected from the group consisting of Group II, Group
III, Group IV and synthetic ester base stocks; [0126] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); and [0127] (C) an
alkylated diphenylamine; [0128] (D) a zinc dialkyldithiophosphate;
[0129] (E) an oil soluble organomolybdenum compound; [0130] (F) at
least one component selected from the group consisting of
dispersants and detergents; and [0131] (G) a hindered phenolic
antioxidant, with the proviso that the hindered phenolic
antioxidant is not 4,4'-methylenebis(2,6-di-tert-butylphenol);
wherein the composition comprises: about 600 ppm or less of
phosphorus derived from zinc dialkyldithiophosphate and about
50-400 ppm of molybdenum derived from the oil soluble
organomolybdenum compound.
[0132] In one embodiment of the invention, the oil soluble
organomolybdenum compound comprises sulfur and is phosphorus-free.
In one embodiment, the weight ratio of phosphorus to molybdenum is
greater than or equal to 1.0; in another embodiment the weight
ratio is greater than 0.0 and less than 1.0. In yet another
embodiment of the invention, the weight ratio of phosphorus to
molybdenum is less than or equal to 1.0. In another embodiment of
the invention, the engine oil comprises about 550 ppm or less of
phosphorus derived from the zinc dialkyldithiophosphate. In another
embodiment of the invention, the engine oil comprises about 500 ppm
or less of phosphorus derived from the zinc dialkyldithiophosphate.
In yet another embodiment of the invention, the composition
comprises about 400 ppm or less of phosphorus derived from the zinc
dialkyldithiophosphate. In yet another embodiment, the engine oil
comprises about 300 ppm or less of phosphorus derived from the zinc
dialkyldithiophosphate. In another embodiment of the invention, the
engine oil comprises about 100-250 ppm of molybdenum derived from
the oil soluble organomolybdenum compound. In yet another
embodiment of the invention, the engine oil comprises about 250-400
ppm of molybdenum derived from the oil soluble organomolybdenum
compound. In yet another embodiment of the invention, the engine
oil comprises about 300-400 ppm of molybdenum derived from the oil
soluble organomolybdenum compound. In yet another embodiment of the
invention, the composition comprises about 50-150 ppm of molybdenum
derived from the oil soluble organomolybdenum compound. All parts
per million (ppm) in this paragraph are based on the total weight
of the engine oil
[0133] Yet another aspect of the invention is an engine oil
comprising: [0134] (A) a major amount of oil of lubricating
viscosity selected from the group consisting of Group II, Group
III, Group IV and synthetic ester base stocks; [0135] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); [0136] (C) 0.2 to 1.0
wt % of an alkylated diphenylamine; [0137] (E) 200 to 600 ppm of
phosphorus derived from zinc dialkyldithiophosphate; and [0138] (F)
50 to 400 ppm of molybdenum derived from an oil soluble
organomolybdenum compound; wherein the weight ratio of (B) to (C)
is greater than or equal to 0.5.
[0139] Yet another aspect of the invention is an engine oil
lubricating composition comprising: [0140] (A) a major amount of
oil of lubricating viscosity selected from the group consisting of
Group II, Group III, Group IV and synthetic ester base stocks;
[0141] (B) 0.1 to 1.5 wt %
4,4'-methylenebis(2,6-di-tert-butylphenol); [0142] (C) an alkylated
diphenylamine; [0143] (D) 1.0 to 12.0 wt % of at least one compound
selected from the group consisting of dispersants and detergents;
[0144] (E) 200 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; and [0145] (F) 50 to 400 ppm of molybdenum
derived from an oil soluble organomolybdenum compound; wherein the
weight ratio of (B) to (C) is greater than or equal to 0.5.
[0146] In one embodiment of the invention the engine oil comprises
0.1 to 0.5 wt % of any ester derived from
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid.
[0147] Another aspect of the invention is an engine oil comprising:
[0148] (A) a major amount of oil of lubricating viscosity selected
from the group consisting of Group II, Group III, Group IV and
synthetic ester base stocks; [0149] (B)
4,4'-methylenebis(2,6-di-tert-butylphenol); [0150] (C) 0.2 to 1.0
wt % of an alkylated diphenylamine, and [0151] (E) 300 to 600 ppm
of phosphorus derived from zinc dialkyldithiophosphate; wherein the
weight ratio of (B) to (C) is greater than or equal to 0.5.
[0152] In one embodiment of the invention the engine oil further
comprises 0.1 to 0.5 wt % of any ester derived from
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid.
[0153] Another aspect of the invention is an engine oil comprising:
[0154] (A) a major amount of oil of lubricating viscosity selected
from the group consisting of Group II, Group III, Group IV and
synthetic ester base stocks; [0155] (B) 0.1 to 1.5 wt %
4,4'-methylenebis(2,6-di-tert-butylphenol); [0156] (C) an alkylated
diphenylamine; [0157] (D) 1.0 to 12.0 wt % of at least one compound
selected from the group consisting of dispersants and detergents,
and [0158] (E) 300 to 600 ppm of phosphorus derived from zinc
dialkyldithiophosphate; wherein the weight ratio of (B) to (C) is
greater than or equal to 0.5.
[0159] All weight percents (wt %) given above for the engine oils
of this invention are based on the total weight of the engine oil.
By "a major amount" it is meant an amount greater than 50 wt %
based on the total weight of the engine oil.
[0160] An additional embodiment of this invention is any
composition or engine oil described above further comprising one or
more components selected from the group consisting of an organic
friction modifier, a corrosion inhibitor, a viscosity modifier, a
pour point depressant, and a phosphorus-free anti-wear
additive.
[0161] A further aspect of this invention is a method of reducing
the amount of total volatile organics (both polar and non-polar in
nature) produced by an internal combustion engine upon heating and
oxidation of an engine oil, comprising lubricating the engine with
any composition or engine oil described herein.
[0162] Yet another aspect of this invention is a method of reducing
the amount of deposits in an internal combustion engine comprising
lubricating the engine with any composition or engine oil described
herein.
[0163] A further aspect of this invention is a method of reducing
the poisoning of the catalyst in an internal combustion engine
emission system, comprising lubricating the engine with any
composition or engine oil described herein.
[0164] The following combinations are examples of embodiments of
the invention, in which the sum of (B), (C) and (G) is less than or
equal to about 1.5 wt. % of the composition. TABLE-US-00002
Combination I. Component Wt. % B
4,4'-methylenebis(2,6-di-tert-butylphenol) 0.7 C nonylated
diphenylamine 0.4 G 2,6-di-tert-butylphenol 0.3
[0165] TABLE-US-00003 Combination II. Component Wt. % B
4,4'-methylenebis(2,6-di-tert-butylphenol) 0.6 C nonylated
diphenylamine 0.4 G 3,5-di-tert-butyl-4-hydroxyhydrocinnamic 0.4
acid, isooctyl ester
[0166] The TEOST MHT instrument should be run according to the ASTM
D7097 method and manufacturer specifications. The test involves
passing a thin film of test engine oil over a heated wire-wound
depositor rod with the aide of a precision pump. The test rod is
heated at 285.degree. C. and the test run for 24 hours. The thin
film of oil moves evenly down the rod and is collected at the flow
out point of the test assembly apparatus. Recovered oil is
circulated back to the depositor rod via the precision pump. During
the 24 hour test period volatiles are produced that flash off the
hot rod surface and condense on the glass mantle of the test
assembly apparatus. These volatiles are recovered at the volatiles
out port of the test assembly and are collected in a glass vial. At
the end of the test, deposits are determined by the increase in
depositor rod weight and reported in milligrams (mg). The collected
volatiles are accurately weighed and reported in grams (g).
[0167] The method requires a number of independent calibrations,
including for example, calibrating the air flow rate, the oil pump
rate, the temperature controller settings, and the control
thermocouple. The method also requires running certified reference
oils periodically to determine the severity of the test. For
example, a certified medium deposit reference oil should produce
approximately 40-60 mg of deposits, while a certified high deposit
reference oil should produce approximately 70-90 mg of deposits. It
is understood that a severe test condition will usually produce
heavier deposits and higher levels of volatiles. On the other hand,
a mild test condition will usually produce lighter deposits and
much lower levels of volatiles. Engine oils that perform well, i.e.
low deposits and low volatiles, under a severe test condition are
expected to perform even better under a mild test condition.
However, engine oils that perform well under a mild test condition
are expected to perform worse under a severe test condition. The
additive combination of this invention gives excellent deposit
control and reduced volatiles formation under both severe and mild
conditions. The robust performance of the new additive combination
under both severe and mild test conditions is another advantage of
this invention.
III. EXAMPLES
[0168] Measurement of Deposits and Volatiles in TEOST-MHT
[0169] The fully formulated oil (8.4 g) and an organometallic
catalyst (about 0.1 g) are added to a flask equipped with a Teflon
stirring bar and stirred for 20-60 minutes without heating. The
depositor rod, sample flask, oil inlet, air inlet, and volatiles
collection vial are fitted to the TEOST apparatus according to
manufacturers specifications. The pump is started at a high flow
rate and run until the test oil reaches the connection of the pump
and oil feed tube, at which point the pump flow is turned to zero.
The heater switch is turned on and when the depositor rod
temperature controller is between 200-210.degree. C., the pump
speed increased to achieve a sample delivery of 0.25.+-.0.02 g/min,
making sure that the oil is flowing down the depositor rod and is
not leaking. The temperature is allowed to stabilize at
285.+-.2.degree. C. and the test is run under these conditions for
24 hrs.
[0170] Three test tubes are prepared with cyclohexane or another
suitable hydrocarbon solvent for extraction of oil from the
depositor rod. The test instrument is disassembled as per
manufacturer's instructions and the depositor rod is transferred to
a weighing boat and kept under cover. The depositor rod is placed
successively for 10 minutes each in each of the three test tubes
prepared with a hydrocarbon solvent. The rod is placed in tared
weighing boat and allowed to sit for 10 minutes to insure
evaporation of the hydrocarbon solvent. The rod and the boat are
weighed, verifying that a constant mass has been achieved. The
contents of the three test tubes, along with the lower-end cap
deposits and glass mantle deposits, are washed into a common
container which is then filtered using a glass funnel equipped with
a filter cartridge. After completing the filtering, the filter
cartridge is dried under vacuum and weighed, until a constant mass
is achieved. The total mass of the deposits from the depositor rod
and filter deposits is then determined.
[0171] During the 24 hour duration of the test, the volatile
compounds in the formulated oil that are there originally or those
formed during the test, are flashed off the depositor rod. These
volatiles condense on the glass mantle and are collected on a
continuous basis in a small, weighed vial. The vial and volatiles
are measured at the end of the 24 hour test period and the amount
of volatiles is calculated by subtracting the original weight of
the vial.
Example A
[0172] A preblend was prepared by blending the following materials:
[0173] 150N Group II Baseoil, 92.1 wt. %; [0174] an ashless
dispersant concentrate, 4.92 wt. %; [0175] an overbased detergent
concentrate containing calcium, 1.85 wt. %; [0176] a neutral
detergent concentrate containing calcium, 0.51 wt. %; and [0177] a
secondary zinc dialkyldithiophosphate, 0.62 wt.
[0178] To this preblend was added the following components as
indicated in Table 2 in preparation of a variety of engine oils.
The finished engine oil contained the following (calculated):
calcium 2400 ppm; phosphorus 470 ppm; zinc 520 ppm; and had a total
base number of 7.5 mg KOH/g of oil.
[0179] The finished oils were tested in the TEOST MHT according to
ASTM D7097. The certified medium deposit reference oil produced
60.6 mg of deposits in a calibration experiment. The certified high
deposit reference oil produced 96.8 mg of deposits in a calibration
experiment; these results represent a severe condition for the
TEOST MHT instrument. The results of the analysis under severe
conditions are reported in Table 2. TABLE-US-00004 TABLE 2
Composition and Total Deposits for Examples A.1-A.17 from ASTM
D7097 Total Total Ex. MoDTC Mo SO NDPA HPE MBBP MBDTBP Volatiles
Deposits No. (g) (ppm) (g) (g) (g) (g) (g) (g)* (mg)* A.1
Comparative 1.00 1.00 44 A.2 Comparative 1.50 3.2 50 2.8 46 A.3
Comparative 0.75 2.7 55 A.4 Comparative 0.80 360 0.75 2.8 50 A.5
Comparative 0.80 360 1.50 3.1 25 2.5 31 A.6 Comparative 0.75 0.40
2.5 39 2.7 41 A.7 Comparative 0.75 0.75 3.0 41 A.8 Comparative 0.75
0.40 2.4 33 2.4 46 A.9 Comparative 0.75 0.75 2.7 29 A.10 Invention
0.75 0.40 3.2 44 A.11 Invention 0.75 0.75 2.3 14 A.12 Comparative
0.80 360 0.75 0.40 2.5 29 2.4 28 A.13 Comparative 0.80 360 0.75
0.75 2.2 26 2.6 28 A.14 Comparative 0.80 360 0.75 0.40 3.1 35 A.15
Comparative 0.80 360 0.75 0.75 2.6 19 A.16 Invention 0.80 360 0.75
0.40 2.2 32 A.17 Invention 0.80 360 0.75 0.75 2.2 12 1.9 10 MoDTC =
Molybdenum bis(dialkyldithiocarbamate) containing 4.5 wt. %
molybdenum SO = Sulfurized Olefin containing 12 wt. % sulfur NDPA =
Nonylated diphenylamine HPE =
3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid,
C.sub.7-C.sub.9-branched alkyl esters MBBP = Non-volatile
multi-ring (or methylene bridged) tert-butylphenolics MBDTBP =
4,4'-methylenebis(2,6-di-tert-butylphenol) *more than one result
indicates a duplicated run
[0180] Table 2 clearly shows that the combination of MBDTBP, NDPA
and MoDTC in the invention leads to low levels of deposits (12 and
10 mg) and volatiles (2.2 and 1.9 g) in the TEOST MHT using ASTM
D7097. It is also clear that the combination of MBDTBP and NDPA
without MoDTC in the invention leads to low levels of deposits (14
mg) and volatiles (2.3 g) in the TEOST MHT using ASTM D7097.
[0181] A graph of the deposit results in the presence of MoDTC is
shown in FIG. 1.
[0182] A graph of the deposit results in the absence of MoDTC is
shown in FIG. 2.
Example B
Oil Thickening and Oxidation at Elevated Temperatures
[0183] A preblend was prepared by blending the following materials:
[0184] 4.92 wt. % of an ashless dispersant concentrate; [0185] 1.85
wt. % of an overbased detergent concentrate containing calcium;
[0186] 0.51 wt. % of a neutral detergent concentrate containing
calcium; [0187] 0.62 wt. % of a secondary zinc
dialkyldithiophosphate; and [0188] 92.10 wt. % of a 150N Group II
baseoil.
[0189] To this engine oil preblehd was added the components
indicated in Table 3. TABLE-US-00005 TABLE 3 Components of Examples
B.1-B.6. Engine Oil Ex. Preblend HPE NDPA ZDDP MoN SO MBDTBP G2BO
Total No. Example Type (wt %) (wt %) (wt %) (wt %) (wt %) (wt %)
(wt %) (wt %) (wt %) B.1 Comparative 97.50 0.75 0.75 1.00 100.00
B.2 Comparative 97.50 0.75 0.75 0.29 0.71 100.00 B.3 Comparative
97.50 0.75 0.75 0.50 0.50 100.00 B.4 Comparative 97.50 0.75 0.75
1.00 100.00 B.5 Comparative 97.50 0.75 0.75 0.25 0.50 0.25 100.00
B.6 Invention 97.50 0.75 0.50 0.40 0.85 100.00 MoN = A
nitrogen-containing organomolybdenum compound containing 7.2 wt. %
molybdenum G2BO = 150 N Group II baseoil
[0190] These finished engine oils contained the following elements
and physical properties (calculated): For examples B.1, B.3, B.4,
B.5, and B.6: calcium 2400 ppm; phosphorus 470 ppm; zinc 520 ppm;
and a total base number (TBN) of 8.6 mg KOH/g of oil. For example
B.2: calcium 2400 ppm; phosphorus 690 ppm; zinc 765 ppm; and a
total base number of 8.6 mg KOH/g of oil.
[0191] The oxidative stability of these finished engine oils was
evaluated in a bulk oil oxidation test. Each oil (300 mL) was
treated with an iron naphthenate oxidation catalyst to deliver 110
ppm of iron to the finished oil. The oils were heated in a block
heater at 160.degree. C., while 10 liters/hour of dry oxygen was
bubbled through the oil. Samples of the oxidized oils were removed
at 24, 48, 72 and 96 hours. Kinematic viscosities of each sample
were determined at 40.degree. C. The percent viscosity increase of
the oxidized oil versus the fresh oil was calculated. The percent
viscosity increase results are shown in Table 4. TABLE-US-00006
TABLE 4 Percent viscosity increase of finished oils B.1-B.6 in bulk
oil oxidation test. Time Ex. B.1 Ex. B.2 Ex. B.3 Ex. B.4 Ex. B.5
Ex. B.6 (hrs) Comparative Comparative Comparative Comparative
Comparative Invention 24 75.6 35.6 3.8 31.6 3.7 2.3 48 328.3 165.2
6.0 116.2 26 4.2 72 TVTM 466.3 111.6 287.7 225.4 31.0 96 TVTM TVTM
952.7 338.7 TVTM 256.3 TVTM = too viscous to measure
[0192] A higher percent viscosity increase is a measure of
increased oxidation and degradation of the lubricant. The
designation TVTM is an indication of severe degradation of the
lubricant. These results clearly show that the inventive
antioxidant combination in Example B.6 provides superior oxidation
protection compared to the other Examples (B.1-B.5). Antioxidant
systems that do not contain the organomolybdenum component (B.1,
B.2 and B.4) show poor oxidation control, while the system
containing the hindered phenolic MBDTBP (B.6) is superior to the
system containing the hindered phenolic HPE (B.3).
Example C
Oil Thickening and Oxidation
[0193] Oils A.2, A.3, A.7, A.9, A.11, A.13, A.15, A.16, and A.17
(Table 2) were evaluated in the bulk oil oxidation test described
in Example B. In this study the oils were heated in a heating block
at 150.degree. C., while 10 liters/hour of dry oxygen was bubbled
through the oil. Samples of the oxidized oils were removed at 24,
48, 72 and 96 hours. Kinematic viscosities of each sample were
determined at 40.degree. C. The percent viscosity increase of the
oxidized oil versus the fresh oil was calculated. The percent
viscosity increase results are shown in Table 5. TABLE-US-00007
TABLE 5 Percent viscosity increase of oils A.2, A.3, A.7, A.9, and
A.11 in bulk oil oxidation test. Time Oil A.2 Oil A.3 Oil A.7 Oil
A.9 Oil A.11 Oil A.13 Oil A.15 Oil A.16 Oil A.17 (hrs) Compar.
Compar. Compar. Compar. Inventive Compar. Compar. Inventive
Inventive 24 2 0 10 0 1 n/a n/a n/a n/a 48 51 112 151 48 52 2.1 0.7
0 1.6 72 193 313 429 201 207 3.0 1.9 0.7 3.3 96 461 753 1129 535
526 2.8 2.0 1.5 -0.3 n/a = not measured
[0194] These results show that Oil A.11 is comparable to Oils A.2
and A.9, and significantly better than Oils A.3 and A.7. However,
Oil A.11 also shows a significant improvement in deposit control
and volatiles relative to all the oils, as was demonstrated in
Example A. Therefore, the Inventive Oil A.11 is an overall better
performing engine oil, providing excellent viscosity control,
deposit control, and control of volatile organic compounds. The
ability of the inventive Oil A.11 to show benefits in all these
parameters is of value. Antioxidant systems that contain the
organomolybdenum compound (A.13, A.15, A.16 and A.17) show superior
viscosity control.
[0195] The foregoing examples are not limiting and are merely
illustrative of various aspects and embodiments of the present
invention. All documents cited herein are indicative of the levels
of skill in the art to which the invention pertains and are
incorporated by reference herein in their entireties for any
purpose. None, however, is admitted to be prior art.
[0196] One skilled in the art will readily appreciate that the
present invention is well adapted to carry out the objects and
obtain the ends and advantages mentioned, as well as those inherent
therein. The methods and compositions described illustrate a
variety of embodiments, are exemplary, and are not intended as
limitations on the scope of the invention. Certain modifications
and other uses will occur to those skilled in the art and are
encompassed within the spirit of the invention, as defined by the
scope of the claims.
[0197] The invention illustratively described herein may be
suitably practiced in the absence of any element or elements,
limitation or limitations which is not specifically disclosed
herein. The terms and expressions which have been employed are used
as terms of description and not of limitation, and there is no
intention in of the use of such terms and expressions of excluding
any equivalents of the features shown and described, or portions
thereof. It is recognized that various modifications are possible
within the scope of the invention claimed. Thus, it should be
understood that although the present invention has been
specifically disclosed by described embodiments, optional features,
modification and variations of the concepts herein disclosed may be
resorted to by those skilled in the art and such modifications and
variations are considered to be within the scope of this invention
as defined by the description and the appended claims.
* * * * *