U.S. patent application number 14/219284 was filed with the patent office on 2015-06-25 for method for improving engine fuel efficiency.
This patent application is currently assigned to ExxonMobil Research and Engineering Company. The applicant listed for this patent is Douglas Edward DECKMAN, Dennis A. GAAL, Erik HERZ, Mrugesh Nilesh PATEL. Invention is credited to Douglas Edward DECKMAN, Dennis A. GAAL, Erik HERZ, Mrugesh Nilesh PATEL.
Application Number | 20150175923 14/219284 |
Document ID | / |
Family ID | 53399346 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150175923 |
Kind Code |
A1 |
GAAL; Dennis A. ; et
al. |
June 25, 2015 |
METHOD FOR IMPROVING ENGINE FUEL EFFICIENCY
Abstract
A method for improving fuel efficiency and reducing frictional
properties while maintaining or improving deposit control, in an
engine lubricated with a lubricating oil by using as the
lubricating oil a formulated oil. The formulated oil has a
composition including a lubricating oil base stock as a major
component, and a friction modifier mixture as a minor component.
Fuel efficiency and frictional properties are improved and deposit
control is maintained or improved as compared to frictional
properties and deposit control achieved using a lubricating engine
oil containing a minor component other than the friction modifier
mixture. A lubricating engine oil having a composition including a
lubricating oil base stock as a major component, and a friction
modifier mixture as a minor component. The lubricating engine oils
are useful in internal combustion engines including direct
injection, gasoline and diesel engines.
Inventors: |
GAAL; Dennis A.; (Glassboro,
NJ) ; HERZ; Erik; (Brookhaven, PA) ; PATEL;
Mrugesh Nilesh; (Philadelphia, PA) ; DECKMAN; Douglas
Edward; (Mullica Hill, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GAAL; Dennis A.
HERZ; Erik
PATEL; Mrugesh Nilesh
DECKMAN; Douglas Edward |
Glassboro
Brookhaven
Philadelphia
Mullica Hill |
NJ
PA
PA
NJ |
US
US
US
US |
|
|
Assignee: |
ExxonMobil Research and Engineering
Company
Annandale
NJ
|
Family ID: |
53399346 |
Appl. No.: |
14/219284 |
Filed: |
March 19, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61920169 |
Dec 23, 2013 |
|
|
|
Current U.S.
Class: |
508/517 |
Current CPC
Class: |
C10M 2209/104 20130101;
C10M 2223/045 20130101; C10M 2209/103 20130101; C10M 2207/021
20130101; C10N 2030/04 20130101; C10M 2205/0285 20130101; C10M
141/06 20130101; C10M 2207/04 20130101; C10N 2030/42 20200501; C10N
2030/54 20200501; C10M 2209/084 20130101; C10M 2219/046 20130101;
C10N 2030/06 20130101; C10M 2215/28 20130101; C10M 2229/02
20130101; C10M 2219/044 20130101; C10M 2207/262 20130101; C10N
2010/04 20130101; C10M 2207/144 20130101; C10M 2207/26 20130101;
C10N 2040/25 20130101; C10M 2203/1006 20130101; C10M 2205/02
20130101; C10M 129/68 20130101; C10M 2215/082 20130101; C10M
2209/109 20130101; C10N 2060/14 20130101; C10M 161/00 20130101;
C10M 2207/026 20130101; C10M 2219/068 20130101; C10N 2010/12
20130101; C10M 2203/1025 20130101; C10M 2207/289 20130101; C10N
2030/45 20200501; C10M 141/12 20130101; C10M 2215/26 20130101; C10M
129/76 20130101; C10M 2209/062 20130101; C10M 2207/283 20130101;
C10M 2207/28 20130101; C10M 2215/064 20130101; C10M 2209/104
20130101; C10M 2209/109 20130101; C10M 2203/1025 20130101; C10N
2020/02 20130101; C10M 2215/28 20130101; C10N 2060/14 20130101;
C10M 2207/289 20130101; C10N 2060/14 20130101; C10M 2223/045
20130101; C10N 2010/04 20130101; C10M 2209/062 20130101; C10M
2209/086 20130101; C10M 2219/068 20130101; C10N 2010/12 20130101;
C10M 2207/26 20130101; C10N 2010/04 20130101; C10M 2219/044
20130101; C10N 2010/04 20130101; C10M 2219/046 20130101; C10N
2010/04 20130101; C10M 2207/144 20130101; C10N 2010/04 20130101;
C10M 2219/068 20130101; C10N 2010/12 20130101; C10M 2203/1025
20130101; C10N 2020/02 20130101; C10M 2223/045 20130101; C10N
2010/04 20130101; C10M 2207/26 20130101; C10N 2010/04 20130101;
C10M 2219/044 20130101; C10N 2010/04 20130101; C10M 2219/046
20130101; C10N 2010/04 20130101; C10M 2207/144 20130101; C10N
2010/04 20130101; C10M 2215/28 20130101; C10N 2060/14 20130101;
C10M 2207/289 20130101; C10N 2060/14 20130101 |
International
Class: |
C10M 129/68 20060101
C10M129/68 |
Claims
1. A method fur improving fuel efficiency and reducing frictional
properties, while maintaining or improving deposit control, in an
engine lubricated with a lubricating oil by using as the
lubricating oil a formulated oil, said formulated oil having a
composition comprising a lubricating oil base stock as a major
component; and a friction modifier mixture comprising a first
friction modifier, and at least one other friction modifier
different from said first friction modifier, as a minor component;
wherein said first friction modifier and said at least one other
friction modifier are selected from the group consisting of an
alkoxylated fatty acid ester, alkanolamide, glycerol fatty acid
ester, borated glycerol fatty acid ester, and fatty alcohol ether;
and wherein fuel efficiency and friction reduction properties are
improved and deposit control is maintained or improved as compared
to friction reduction properties and deposit control achieved using
a lubricating engine oil containing a minor component other than
the friction modifier mixture.
2. The method of claim 1 wherein the lubricating oil base stock
comprises a. Group I, Group II, Group III, Group IV or Group V base
oil.
3. The method of claim 1 wherein, in comparison with fuel
efficiency achieved using a lubricating engine oil containing a
minor component other than the friction modifier mixture, the
lubricating engine oil containing the friction modifier mixture
exhibits a fuel efficiency, FEI sum, greater than 1.1.times., as
determined by a Sequence VID Fuel Economy (ASTM D7589) engine
test.
4. The method of claim 4 wherein the alkoxylated fatty acid ester
is selected from polyoxyethylene stearate and fatty acid polyglycol
ester; the alkanolamide is selected from lauric acid
diethylalkanolamide and palmic acid diethylalkanolamide; the
glycerol fatty acid ester is selected from mixed glyceride ester
and glycerol mono-stearate; the borated glycerol fatty acid ester
is selected from borated mixed glyceride ester and borated glycerol
mono-sterate; and the fatty alcohol ether is selected from stearyl
ether and myristyl ether.
5. The method of claim 1 wherein the friction modifier mixture
comprises an ethoxylated fatty acid ester and a glycerol fatty acid
ester.
6. The method of claim 1 wherein the lubricating oil base stock
comprises a Group I, Group II, Group III, Group IV and/or Group V
base oil the friction modifier mixture comprises an ethoxylated
fatty acid ester and a glycerol fatty acid ester.
7. The method of claim 1 wherein the weight ratio of the first
friction modifier to the other friction modifier is from 0.1:1 to
1:0.1.
8. The method of claim 1 wherein the lubricating oil base stock is
present in an amount of from 70 weight percent to 95 weight
percent, and the friction modifier mixture is present in an amount
of from 0.01 weight percent to 2.5 weight percent, based on the
total, weight of the formulated oil.
9. The method of claim 1 wherein the lubricating oil base stock is
present in an amount of from 70 weight percent to 95 weight
percent, and the friction modifier mixture is present in an amount
of from 0.01 weight percent to 1.0 weight percent, based on the
total weight of the formulated oil.
10. The method of claim 1 wherein the lubricating oil further
comprises one or more of an anti-wear additive, viscosity index
improver, antioxidant, detergent, dispersant, pour point
depressant, corrosion inhibitor, metal deactivator, seal
compatibility additive, anti-foam agent, inhibitor, anti-rust
additive, and organic metallic friction modifier.
11. The method of claim 1 wherein, in friction measurements of the
lubricating oil by mini-traction machine (MTM) in Stribeck mode at
140.degree. C., the integrated Stribeck friction coefficient of the
lubricating oil in the MTM is reduced as compared to the integrated
Stribeck friction coefficient of a lubricating oil containing a
minor component other than the friction modifier mixture; and
wherein, in deposit measurements of the lubricating oil by
thermo-oxidation engine oil simulation TEOST 33C, the amount of
total deposits is reduced or maintained as compared to the amount
of total deposits in a lubricating oil containing a minor component
other than the friction modifier mixture.
12. A lubricating engine oil having a composition comprising a
lubricating oil base stock as a major component; and a friction
modifier mixture comprising a first friction modifier, and at least
one other friction modifier different from said first friction
modifier, as a minor component; wherein said first friction
modifier and said at least one other friction modifier are selected
from the group consisting of an alkoxylated fatty acid ester,
alkanolamide, glycerol fatty acid ester, borated glycerol fatty
acid ester, and fatty alcohol ether; and wherein fuel efficiency
and friction reduction properties are improved and deposit control
is maintained or improved as compared to friction reduction
properties and deposit control achieved using a lubricating engine
oil containing a minor component other than the friction modifier
mixture.
13. The lubricating engine oil of claim 12 wherein the lubricating
oil base stock comprises a Group I, Group II, Group III, Group IV
or Group V base oil.
14. The lubricating engine oil of claim 12 wherein, in comparison
with fuel efficiency achieved using a lubricating engine oil
containing a minor component other than the friction modifier
mixture, the lubricating engine oil containing the friction
modifier mixture exhibits a fuel efficiency, FEI sum, greater than
1.1.times., as determined by a Sequence VID Fuel Economy (ASTM
D7589) engine test.
15. The lubricating engine oil of claim 12 wherein the alkoxylated
fatty acid ester is selected from polyoxyethylene stearate and
fatty acid polyglycol ester; the alkanolamide is selected from
lauric acid diethylalkanolamide and palmic acid
diethylalkanolamide; the glycerol fatty acid ester is selected from
mixed glyceride ester and glycerol mono-stearate; the borated
glycerol fatty acid ester is selected from borated mixed glyceride
ester and borated glycerol mono-sterate; and the fatty alcohol
ether is selected from stearyl ether and myristyl ether.
16. The lubricating engine oil of claim 12 wherein the friction
modifier mixture comprises an ethoxylated fatty acid ester and a
glycerol fatty acid ester.
17. The lubricating engine oil of claim 12 wherein the lubricating
oil base stock comprises a Group I, Group II, Group III, Group IV
and/or Group V base oil the friction modifier mixture comprises an
ethoxylated fatty acid ester and a glycerol fatty acid ester.
18. The lubricating engine oil of claim 12 wherein the weight ratio
of the first friction modifier to the other friction modifier is
from 0.1:1 to 1:0.1.
19. The lubricating engine oil of claim 12 wherein the lubricating
oil base stock is present in an amount of from 70 weight percent to
95 weight percent, and the friction modifier mixture is present in
an amount of from 0.01 weight percent to 2.5 weight percent, based
on the total weight of the formulated oil.
20. The lubricating engine oil of claim 12 wherein the lubricating
oil base stock is present in an amount of from 70 weight percent to
95 weight percent, and the friction modifier mixture is present in
an amount of from 0.01 weight percent to 1.0 weight percent, based
on the total weight of the formulated oil.
21. The lubricating engine oil of claim 12 wherein the lubricating
oil further comprises one or more of an anti-wear additive,
viscosity index improver, antioxidant, detergent, dispersant, pour
point depressant, corrosion inhibitor, metal deactivator, seal
compatibility additive, anti-foam agent, inhibitor, anti-rust
additive, and organic metallic friction modifier.
22. The lubricating engine oil of claim 12 wherein the lubricating
oil is a passenger vehicle engine oil (PVEO).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/920,169 filed Dec. 23, 2013, herein incorporated
by reference.
FIELD
[0002] This disclosure relates to improving fuel efficiency and
friction reduction properties, while maintaining or improving
deposit control, in an engine lubricated with a lubricating oil by
including a friction modifier mixture, in the lubricating oil.
BACKGROUND
[0003] Fuel efficiency requirements for passenger vehicles are
becoming increasingly more stringent. New legislation in the United
States and European Union within the past few years has set fuel
economy and emissions targets not readily achievable with today's
vehicle and lubricant technology.
[0004] To address these increasing standards, automotive original
equipment manufacturers are demanding better fuel economy as a
lubricant-related performance characteristic, while maintaining
deposit control and oxidative stability requirements. One well
known way to increase fuel economy is to decrease the viscosity of
the lubricating oil. However, this approach is now reaching the
limits of current equipment capabilities and specifications. At a
given viscosity, it is well known that adding organic or organic
metallic friction modifiers reduces the surface friction of the
lubricating oil and allows for better fuel economy. However these
additives often bring with them detrimental effects such as
increased deposit formation, seals impacts, or they out-compete the
anti-wear components for limited surface sites, thereby not
allowing the formation of an anti-wear film, causing increased
wear.
[0005] Contemporary lubricants such as engine oils use mixtures of
additives such as dispersants, detergents, inhibitors, viscosity
index improvers and the like to provide engine cleanliness and
durability under a wide range of performance conditions of
temperature, pressure, and lubricant service life.
[0006] Lubricant-related performance characteristics such as high
temperature deposit control and fuel economy are extremely
advantageous attributes as measured by a variety of bench and
engine tests. As indicated above, it is known that adding organic
friction modifiers to a lubricant formulation imparts frictional
benefits at low temperatures, consequently improving the lubricant
fuel economy performance. At to high temperatures, however, adding
increased levels of organic friction modifier can invite high
temperature performance issues. For example, engine deposits are
undesirable consequences of high levels of friction modifier in an
engine oil formulation at high temperature engine operation.
[0007] A major challenge in engine oil formulation is
simultaneously achieving high temperature deposit control while
also achieving improved fuel economy.
[0008] Despite the advances in lubricant oil formulation
technology, there exists a need for an engine oil lubricant that
effectively improves fuel economy while maintaining or improving
friction reduction properties and deposit control.
SUMMARY
[0009] This disclosure relates in part to a method for improving
fuel efficiency and reducing frictional properties, while
maintaining or improving deposit control, in an engine lubricated
with a lubricating oil by including a friction modifier mixture in
the lubricating oil. The lubricating oils of this disclosure are
useful in internal combustion engines including direct injection,
gasoline and diesel engines.
[0010] This disclosure also relates in part to a method for
improving fuel efficiency and reducing frictional properties, while
maintaining or improving deposit control, in an engine lubricated
with a lubricating oil by using as the lubricating oil a formulated
oil. The formulated oil has a composition comprising a lubricating
oil base stock as a major component; and a friction modifier
mixture comprising a first friction modifier, and at least one
other friction modifier different from the first friction modifier,
as a minor component. The first friction modifier and the at least
one other friction modifier are selected from an alkoxylated fatty
acid ester, alkanolamide, polyol fatty acid ester, borated glycerol
fatty acid ester, and fatty alcohol ether. Fuel efficiency and
friction reduction properties are improved and deposit control is
maintained or improved as compared to friction reduction properties
and deposit control achieved using a lubricating engine oil
containing a minor component other than the friction modifier
mixture.
[0011] This disclosure further relates in part to a lubricating
engine oil having a composition comprising a lubricating oil base
stock as a major component; and a friction modifier mixture
comprising a first friction modifier, and at least one other
friction modifier different from the first friction modifier, as a
minor component. The first friction modifier and the at least one
other friction modifier are selected from an alkoxylated fatty acid
ester, alkanolamide, polyol fatty acid ester, borated glycerol
fatty acid ester, and fatty alcohol ether. Fuel efficiency and
friction reduction properties are improved and deposit control is
surprisingly maintained or improved as compared to friction
reduction properties and deposit control achieved using a
lubricating engine oil containing a minor component other than the
friction modifier mixture.
[0012] It has been surprisingly found that, in accordance with this
disclosure, improvements in fuel economy and friction reduction
properties are obtained without sacrificing engine cleanliness
(e.g., while maintaining or improving deposit control) in an engine
lubricated with a lubricating oil, by including a friction modifier
mixture in the lubricating oil.
[0013] Other objects and advantages of the present disclosure will
become apparent from the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows a comparison of testing results of three 0W-20
oils for cleanliness and friction in accordance with embodiments of
this disclosure.
[0015] FIG. 2 graphically shows average integrated Stribeck
friction coefficients from mini-traction machine (MTM) measurements
performed at 140.degree. C. as a function of ethoxylated fatty
ester treat rate and other friction modifier treat variations.
[0016] FIG. 3 graphically shows MTM Stribeck friction coefficient
plots showing 0W-20 baseline reference (in light blue at top) and
traces 1-10 of the same formulation containing only ethoxylated
fatty ester as a friction modifier.
[0017] FIG. 4 shows formulation embodiments of this disclosure
(e.g., organic friction modifier boost and combo boost).
Formulation details are shown in weight percent based on the total
weight percent of the formulation, of various formulations. FIG. 4
also shows the results of bench testing of the formulations using
thermo-oxidation engine oil simulation (TEOST 33C) measured by ASTM
D6335.
[0018] FIG. 5 shows formulation details in weight percent based on
the total weight percent of the formulation, of various
formulations. FIG. 5 also shows the results of bench testing of the
formulations using thermo-oxidation engine oil simulation TEOST 33C
and MTM friction.
[0019] FIG. 6 shows formulation details in weight percent based on
the total weight percent of the formulation, of various
formulations. FIG. 6 also shows the results of bench testing of the
formulations using thermo-oxidation engine oil simulation TEOST 33C
and MTM friction.
[0020] FIG. 7 depicts other exemplary lubricant formulations of the
present disclosure with individual contributions of components used
in such formulations.
[0021] FIG. 8 depicts still other exemplary formulations of the
present disclosure with individual contributions of components used
in such formulations.
[0022] FIG. 9 depicts still yet other exemplary formulations of the
present disclosure with individual contributions of components used
in such formulations.
DETAILED DESCRIPTION
[0023] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0024] it has now been found that improved fuel efficiency and
friction reduction properties can be attained, while deposit
control is unexpectedly maintained or improved, in an engine
lubricated with a lubricating oil by using as the lubricating oil a
formulated oil that has a friction modifier mixture. The formulated
oil preferably comprises a lubricating oil base stock as a major
component, and a friction modifier mixture, a metal dialkyl dithio
phosphate, and a viscosity index improver, as minor components. The
lubricating oils of this disclosure are particularly advantageous
as passenger vehicle engine oil (PVEO) products.
[0025] The lubricating oils of this disclosure provide excellent
engine protection including friction reduction and anti-wear
performance. This benefit has been demonstrated for the lubricating
oils of this disclosure in the Sequence VID (ASTM D7589) engine
tests. The lubricating oils of this disclosure provide improved
fuel efficiency. A lower HTHS viscosity engine oil generally
provides superior fuel economy to a higher HTHS viscosity product.
This benefit has been demonstrated for the lubricating oils of this
disclosure in the Sequence VID Fuel Economy (ASTM D7589) engine
test.
[0026] The lubricating engine oils of this disclosure have a
composition sufficient to pass wear protection requirements of one
or more engine tests selected from Sequence VID and others.
[0027] In comparison with fuel efficiency achieved using a
lubricating engine oil containing a minor component other than the
friction modifier mixture, the lubricating engine oils containing
the friction modifier mixture of this disclosure can exhibit a fuel
efficiency improvement preferably greater than 10%, as determined
by the Sequence VID Fuel Economy (ASTM D7589) engine test.
Lubricating Oil Base Stocks
[0028] A wide range of lubricating base oils is known in the art.
Lubricating base oils that are useful in the present disclosure are
both natural oils, and synthetic oils, and unconventional oils (or
mixtures thereof) can be used unrefined, refined, or rerefined (the
latter is also known as reclaimed or reprocessed oil). Unrefined
oils are those obtained directly from a natural or synthetic source
and used without added purification. These include shale oil
obtained directly from retorting operations, petroleum oil obtained
directly from primary distillation, and ester oil obtained directly
from an esterification process. Refined oils are similar to the
oils discussed for unrefined oils except refined oils are subjected
to one or more purification steps to improve at least one
lubricating oil property. One skilled in the art is familiar with
many purification processes. These processes include solvent
extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as a feed stock.
[0029] Groups I, II, III, IV and V are broad base oil stock
categories developed and defined by the American Petroleum
Institute (API Publication 1509; www.API.org) to create guidelines
for lubricant base oils. Group I base stocks have a viscosity index
of between 80 to 120 and contain greater than 0.03% sulfur and/or
less than 90% saturates. Group II base stocks have a viscosity
index of between 80 to 120, and contain less than or equal to 0.03%
sulfur and greater than or equal to 90% saturates. Group III stocks
have a viscosity index greater than 120 and contain less than or
equal to 0.03% sulfur and greater than 90% saturates. Group IV
includes polyalphaolefins (PAO). Group V base stock includes base
stocks not included in Groups I-IV. The table below summarizes
properties of each of these five groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I <90 and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV
Polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III or IV
[0030] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source, for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful. Natural oils vary also
as to the method used for their production and purification, for
example, their distillation range and whether they are straight run
or cracked, hydrorefined, or solvent extracted.
[0031] Group II and/or Group III hydroprocessed or hydrocracked
basestocks, including synthetic oils such as polyalphaolefins,
alkyl aromatics and synthetic esters are also well known basestock
oils.
[0032] Synthetic oils include hydrocarbon oil. Hydrocarbon oils
include oils such as polymerized and inter olefins (polybutylenes,
polypropylenes, propylene isobutylene copolymers, ethylene-olefin
copolymers, and ethylene-alphaolefin copolymers, for example).
Polyalphaolefin (PAO) oil base stocks are commonly used synthetic
hydrocarbon oil. By way of example, PAOs derived from C.sub.6,
C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or mixtures thereof
may be utilized. See U.S. Pat. Nos. 4,956,122; 4,827,064; and
4,827,073.
[0033] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron
Phillips Chemical Company, BP, and others, typically vary from 250
to 3,000, although PAO's may be made in viscosities up to 100 cSt
(100.degree. C.). The PAOs are typically comprised of relatively
low molecular weight hydrogenated polymers or oligomers of
alphaolefins which include, but are not limited to, C.sub.2 to
C.sub.32 alphaolefins with the C.sub.8 to C.sub.16 alphaolefins,
such as 1-hexene, 1-octene, 1-decene, 1-dodecene and the like,
being preferred. The preferred polyalphaolefins are poly-1-hexene,
poly-1-octene, poly-1-decene and poly-1-dodecene and mixtures
thereof and mixed olefin-derived polyolefins. However, the dimers
of higher olefins in the range of C.sub.14 to C.sub.18 may be used
to provide low viscosity base stocks of acceptably low volatility.
Depending on the viscosity grade and the starting oligomer, the
PAOs may be predominantly trimers and tetramers of the starting
olefins, with minor amounts of the higher oligomers, having a
viscosity range of 1.5 to 12 cSt. PAO fluids of particular use may
include 3.0 cSt, 3.4 cSt, and/or 3.6 cSt and combinations thereof.
Bi-modal mixtures of PAO fluids having a viscosity range of 1.5 to
100 cSt may be used if desired.
[0034] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. Nos. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C.sub.14 to C.sub.18
olefins are described in U.S. Pat. No. 4,218,330.
[0035] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof. Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (Li-IDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269, the disclosure of which is incorporated
herein by reference in its entirety. Processes for making
hydrocracked/hydroisomerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Each of the aforementioned patents is incorporated
herein in their entirety. Particularly favorable processes are
described in European Patent Application Nos. 46.4546 and 464547,
also incorporated herein by reference. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. Nos. 4,594,172
and 4,943,672, the disclosures of which are incorporated herein by
reference in their entirety.
[0036] Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived
base oils, and other wax-derived hydroisomerized (wax isomerate)
base oils be advantageously used in the instant disclosure, and may
have useful kinematic viscosities at 100.degree. C. of 3 cSt to 50
cSt, preferably 3 cSt to 30 cSt, more preferably 3.5 cSt to 25 cSt,
as exemplified by GTL 4 with kinematic viscosity of 4.0 cSt at
100.degree. C. and a viscosity index of 141. These Gas-to-Liquids
(GTL) base oils, Fischer-Tropsch wax derived base oils, and other
wax-derived hydroisomerized base oils may have useful pour points
of -20.degree. C. or lower, and under some conditions may have
advantageous pour points of -25.degree. C. or lower, with useful
pour points of -30.degree. C. to -40.degree. C. or lower. Useful
compositions of Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax
derived base oils, and wax-derived hydroisomerized base oils are
recited in U.S. Pat. Nos. 6,080,301; 6,090,989, and 6,165,949 for
example, and are incorporated herein in their entirety by
reference.
[0037] The hydrocarbyl aromatics can be used as base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least 5% of its weight derived from an aromatic moiety such as a
benzenoid moiety or naphthenoid moiety, or their derivatives. These
hydrocarbyl aromatics include alkyl benzenes, alkyl naphthalenes,
alkyl diphenyl oxides, alkyl naphthols, alkyl diphenyl sulfides,
alkylated bis-phenol A, alkylated thiodiphenol, and the like. The
aromatic can be mono-alkylated, dialkylated, polyalkylated, and the
like. The aromatic can be mono- or poly-functionalized. The
hydrocarbyl groups can also be comprised of mixtures of alkyl
groups, alkenyl groups, alkynyl, cycloalkyl groups, cycloalkenyl
groups and other related hydrocarbyl groups. The hydrocarbyl groups
can range from C.sub.6 up to C.sub.60 with a range of C.sub.8 to
C.sub.20 often being preferred. A mixture of hydrocarbyl groups is
often preferred, and up to three such substituents may be present.
The hydrocarbyl group can optionally contain sulfur, oxygen, and/or
nitrogen containing substituents. The aromatic group can also be
derived from natural (petroleum) sources, provided at least 5% of
the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to 50 cSt are
preferred, with viscosities of approximately 3.4 cSt to 20 cSt
often being more preferred for the hydrocarbyl aromatic component.
In one embodiment, an alkyl naphthalene where the alkyl group is
primarily comprised of 1-hexadecene is used. Other alkylates of
aromatics can be advantageously used. Naphthalene or methyl
naphthalene, for example, can be alkylated with olefins such as
octene, decene, dodecene, tetradecene or higher, mixtures of
similar olefins, and the like. Useful concentrations of hydrocarbyl
aromatic in a lubricant oil composition can be 2% to 25%,
preferably 4% to 20%, and more preferably 4% to 15%, depending on
the application.
[0038] Alkylated aromatics such as the hydrocarbyl aromatics of the
present disclosure may be produced by well-known Friedel-Crafts
alkylation of aromatic compounds. See Friedel-Crafts and Related
Reactions, Olah, G. A. (ed.), Inter-science Publishers, New York,
1963. For example, an aromatic compound, such as benzene or
naphthalene, is alkylated by an olefin, alkyl halide or alcohol in
the presence of a Friedel-Crafts catalyst. See Friedel-Crafts and
Related Reactions, Vol. 2, part 1, chapters 14, 17, and 18, See
Olah, G. A. (ed.), Inter-science Publishers, New York, 1964. Many
homogeneous or heterogeneous, solid catalysts are known to one
skilled in the art. The choice of catalyst depends on the
reactivity of the starting materials and product quality
requirements. For example, strong acids such as AlCl.sub.3,
BF.sub.3, or HF may be used. In some cases, milder catalysts such
as FeCl.sub.3 or SnCl.sub.4 are preferred. Newer alkylation
technology uses zeolites or solid super acids.
[0039] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl)sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0040] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols (such as the neopentyl polyols, neopentyl
glycol, trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol,
trimethylol propane, pentaerythritol and dipentaerythritol) with
alkanoic acids containing at least 4 carbon atoms, preferably
C.sub.5 to C.sub.30 acids such as saturated straight chain fatty
acids including caprylic acid, capric acid, tauric acid, myristic
acid, palmitic acid, stearic acid, arachic acid, and behenic acid,
or the corresponding branched chain fatty acids or unsaturated
fatty acids such as oleic acid, or mixtures of any of these
materials.
[0041] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
thiocarboxylic acids containing from 5 to 10 carbon atoms. These
esters are widely available commercially, for example, the Mobil
P-41 and P-51 esters of ExxonMobli Chemical Company.
[0042] Also useful are esters derived from renewable material such
as coconut, palm, rapeseed, soy, sunflower and the like. These
esters may be monoesters, di-esters, polyol esters, complex esters,
or mixtures thereof. These esters are widely available
commercially, for example, the Mobil P-51 ester of ExxonMobil
Chemical Company.
[0043] Engine oil formulations containing renewable esters are
included in this disclosure. For such formulations, the renewable
content of the ester is typically greater than 70 weight percent,
preferably more than 80 weight percent and most preferably more
than 90 weight percent. Renewable esters can be preferred in
combination with the friction modifier mixture.
[0044] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0045] Non-conventional or unconventional base stocks/base oils
include one or more of a mixture of base stock(s) derived from one
or more Gas-to-Liquids (GTL) materials, as well as
isomerate/isodewaxate base stock(s) derived from natural wax or
waxy feeds, mineral and or non-mineral oil waxy feed stocks such as
slack waxes, natural waxes, and waxy stocks such as gas oils, waxy
fuels hydrocracker bottoms, waxy raffinate, hydrocrackate, thermal
crackates, or other mineral, mineral oil, or even non-petroleum oil
derived waxy materials such as waxy materials received from coal
liquefaction or shale oil, and mixtures of such base stocks.
[0046] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds and/or elements as feed
stocks such as hydrogen, carbon dioxide, carbon monoxide, water,
methane, ethane, ethylene, acetylene, propane, propylene, propyne,
butane, butylenes, and butynes. GTL base stocks and/or base oils
are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons; for example, waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feed stocks. GTL base stock(s) and/or base oil(s)
include oils boiling in the lube oil boiling range (1)
separated/fractionated from synthesized GTL materials such as, for
example, by distillation and subsequently subjected to a final wax
processing step which involves either or both of a catalytic
dewaxing process, or a solvent dewaxing process, to produce lube
oils of reduced/low pour point; (2) synthesized wax isomerates,
comprising, for example, hydrodewaxed or hydroisomerized cat and/or
solvent dewaxed synthesized wax or waxy hydrocarbons; (3)
hydrodewaxed or hydroisomerized cat and/or solvent dewaxed
Fischer-Tropsch material (i.e., hydrocarbons, waxy hydrocarbons,
waxes and possible analogous oxygenates); preferably hydrodewaxed
or hydroisomerized/followed by cat and/or solvent dewaxing dewaxed
F-T waxy hydrocarbons, or hydrodewaxed or hydroisomerized/followed
by cat (or solvent) dewaxing dewaxed, F-T waxes, or mixtures
thereof.
[0047] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from 2 mm.sup.2/s to 50 mm.sup.2/s (ASTM D445).
They are further characterized typically as having pour points of
-5.degree. C. to -40.degree. C. or lower (ASTM D97), They are also
characterized typically as having viscosity indices of 80 to 140 or
greater (ASTM D2270).
[0048] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) typically have very low sulfur and
nitrogen content, generally containing less than 10 ppm, and more
typically less than 5 ppm of each of these elements. The sulfur and
nitrogen content of GTL base stock(s) and/or base oil(s) obtained
from material, especially F-T wax, is essentially nil. In addition,
the absence of phosphorous and aromatics make this materially
especially suitable for the formulation of low SAP products.
[0049] The term GTL base stock and/or base oil and/or wax isomerate
base stock and/or base oil is to be understood as embracing
individual fractions of such materials of wide viscosity range as
recovered in the production process, mixtures of two or more of
such fractions, as well as mixtures of one or two or more low
viscosity fractions with one, two or more higher viscosity
fractions to produce a blend wherein the blend exhibits a target
kinematic viscosity.
[0050] The GTL material, from which the GTL base stock(s) and/or
base oil(s) is/are derived is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0051] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) and hydrodewaxed, or
hydroisomerized/cat (and/or solvent) dewaxed base stock(s) and/or
base oil(s) typically have very low sulfur and nitrogen content,
generally containing less than 10 ppm, and more typically less than
5 ppm of each of these elements. The sulfur and nitrogen content of
GTL base stock(s) and/or base oil(s) obtained from F-T material,
especially F-T wax, is essentially nil. In addition, the absence of
phosphorous and aromatics make this material especially suitable
for the formulation of low sulfur, sulfated ash, and phosphorus
(low SAP) products.
[0052] Base oils for use in the formulated lubricating oils useful
in the present disclosure are any of the variety of oils
corresponding to API Group I, Group II, Group III, Group IV, and
Group V oils and mixtures thereof, preferably API Group II, Group
III, Group IV, and Group V oils and mixtures thereof, more
preferably the Group III to Group V base oils due to their
exceptional volatility, stability, viscometric and cleanliness
features. Minor quantities of Group I stock, such as the amount
used to dilute additives for blending into formulated lube oil
products, can be tolerated but should be kept to a minimum, i.e.
amounts only associated with their use as diluent/carrier oil for
additives used on an "as-received" basis. Even in regard to the
Group II stocks, it is preferred that the Group II stock be in the
higher quality range associated with that stock, i.e. a Group II
stock having a viscosity index in the range 100<VI<120.
[0053] The base oil constitutes the major component of the engine
oil lubricant composition of the present disclosure and typically
is present in an amount ranging from 50 to 99 weight percent,
preferably from 70 to 95 weight percent, and more preferably from
85 to 95 weight percent, based on the total weight of the
composition. The base oil may be selected from any of the synthetic
or natural oils typically used as crankcase lubricating oils for
spark-ignited and compression-ignited engines. The base oil
conveniently has a kinematic viscosity, according to ASTM
standards, of 2.5 cSt to 12 cSt (or mm.sup.2/s) at 100.degree. C.
and preferably of 2.5 cSt to 9 cSt (or mm.sup.2/s) at 100.degree.
C. Mixtures of synthetic and natural base oils may be used if
desired. Mixtures of Group III, IV, V may be preferable.
Friction Modifier Mixtures
[0054] Friction modifier mixtures useful in this disclosure are any
materials that can alter the coefficient of friction of a surface
lubricated by any lubricant or fluid containing such material(s).
Mixtures of friction modifiers, also known as friction reducers, or
lubricity agents or oiliness agents, and other such agents that
change the ability of base oils, formulated lubricant compositions,
or functional fluids, to modify the coefficient of friction of a
lubricated surface can be effectively used in combination with the
base oils or lubricant compositions of the present disclosure.
Friction modifier mixtures that lower the coefficient of friction
are particularly advantageous in combination with the base oils and
lube compositions of this disclosure.
[0055] Illustrative friction modifier mixtures useful in the
lubricating engine oil formulations of this disclosure include, for
example, a first friction modifier, and at least one other friction
modifier different from said first friction modifier. The first
friction modifier and the at least one other friction modifier are
selected from the group consisting of an alkoxylated fatty acid
ester, alkanolamide, polyol fatty acid ester, borated glycerol
fatty acid ester, and fatty alcohol ether.
[0056] Illustrative alkoxylated fatty acid esters include, for
example, polyoxyethylene stearate, fatty acid polyglycol ester, and
the like. These can include polyoxypropylene stearate,
polyoxybutylene stearate, polyoxyethylene isosterate,
polyoxypropylene isostearate, polyoxyethylene palmitate.
[0057] Illustrative alkanolamides include, for example, lauric acid
diethylalkanolamide, palmic acid diethylalkanolamide, and the like.
These can include oleic acid diethyalkanolamide, stearic acid
diethylalkanolamide, oleic acid diethylalkanolamide,
polyethoxylated hydrocarbylamides, polypropoxylated
hydrocarbylamides,
[0058] Illustrative polyol fatty acid esters include, for example,
glycerol mono-oleate, saturated mono-, di, and tri-glyceride
esters, glycerol mono-stearate, and the like. These can include
polyol esters and hydroxyl-containing polyol esters. In addition to
glycerol polyols, these can include trimethylolpropane,
pentaerythritol, to sorbitan, and the like. These esters can be
polyol monocarboxylate esters, polyol dicarboxylate esters, and on
occasion polyoltricarboxylate esters. Preferred can be the glycerol
mono-oleates, glycerol dioleates, glycerol trioleates, glycerol
monostearates, glycerol distearates, and glycerol tristearates and
the corresponding glycerol monopalmitates, glycerol dipalmitates,
and glycerol tripalmitates, and the respective isostearates,
linoleates, and the like. On occasion the glycerol esters can be
preferred as well as mixtures containing any of these. Ethoxylated,
propoxylated, butoxylated fatty acid esters of polyols, especially
using glycerol as underlying polyol can be preferred.
[0059] Illustrative borated glycerol fatty acid esters include, for
example, borated glycerol mono-oleate, borated saturated mono-, di,
and tri-glyceride esters, borated glycerol mono-sterate, and the
like.
[0060] Illustrative fatty alcohol ethers include, for example,
stearyl ether, myristyl ether, and the like. Alcohols, including
those that have carbon numbers from C.sub.3 to C.sub.50, can be
ethoxylated, propoxylate, or butoxylated to form the corresponding
fatty alkyl ethers. The underlying alcohol portion can preferably
be stearyl, myristyl, C.sub.11-C.sub.13 hydrocarbon, oleyl,
isosteryl, and the like.
[0061] A preferred friction modifier mixture of this disclosure
comprises an ethoxylated fatty acid ester and a glycerol fatty acid
ester. A preferred formulation of this disclosure comprises a
lubricating oil base stock that includes a Group I, Group II, Group
III, Group IV and/or Group V base oil and a friction modifier
mixture that includes an ethoxylated fatty acid ester and a
glycerol fatty acid ester.
[0062] Useful concentrations of friction modifier mixtures may
range from 0.01 weight percent to 10-15 weight percent or more,
often with a preferred range of 0.1 weight percent to 5 weight
percent, or 0.1 weight percent to 2.5 weight percent, or 0.1 weight
percent to 1.5 weight percent, or 0.1 weight percent to 1 weight
percent. The weight ratio of the first friction modifier to the
other friction modifier can range from 0.1:1 to 1:0.1.
Other Additives
[0063] The formulated lubricating oil useful in the present
disclosure may additionally contain one or more of the other
commonly used lubricating oil performance additives including but
not limited to antiwear agents, dispersants, other detergents,
corrosion inhibitors, rust inhibitors, metal deactivators, extreme
pressure additives, anti-seizure agents, wax modifiers, viscosity
index improvers, viscosity modifiers, fluid-loss additives, seal
compatibility agents, organic metallic friction modifiers,
lubricity agents, anti-staining agents, chromophoric agents,
defoamants, demulsifiers, emulsifiers, densifiers, wetting agents,
gelling agents, tackiness agents, colorants, and others. For a
review of many commonly used additives, see Klamann in Lubricants
and Related Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN
0-89573-177-0, Reference is also made to "Lubricant Additives" by
M. W. Ranney, published by Noyes Data Corporation of Parkridge,
N.J. (1973); see also U.S. Pat. No. 7,704,930, the disclosure of
which is incorporated herein in its entirety. These additives are
commonly delivered with varying amounts of diluent oil, that may
range from 5 weight percent to 50 weight percent.
[0064] The types and quantities of performance additives used in
combination with the instant disclosure in lubricant compositions
are not limited by the examples shown herein as illustrations.
Antiwear Additive
[0065] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) is a useful component of the
lubricating oils of this disclosure. ZDDP can be derived from
primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.2 where R.sup.1 and R.sup.2 are
C.sub.1-C.sub.18 alkyl groups, preferably C.sub.2-C.sub.12 alkyl
groups. These alkyl groups may be straight chain or branched.
Alcohols used in the ZDDP can be 2-propanol, butanol, secondary
butanol, pentanols, hexanols such as 4-methyl-2-pentanol,
n-hexanol, n-octanol, 2-ethyl hexanol, alkylated phenols, and the
like. Mixtures of secondary alcohols or of primary and secondary
alcohol can be preferred. Alkyl aryl groups may also be used.
[0066] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 677A", "LZ 1095" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "RITEC
7169".
[0067] The ZDDP is typically used in amounts of from 0.4 weight
percent to 1.2 weight percent, preferably from 0.5 weight percent
to 1.0 weight percent, and more preferably from 0.6 weight percent
to 0.8 weight percent, based on the total weight of the lubricating
oil, although more or less can often be used advantageously.
Preferably, the ZDDP is a secondary ZDDP and present in an amount
of from 0.6 to 1.0 weight percent of the total weight of the
lubricating oil.
[0068] Low phosphorus engine oil formulations are included in this
disclosure. For such formulations, the phosphorus content is
typically less than 0.12 weight percent preferably less than 0.10
weight percent and most preferably less than 0.085 weight percent.
Low phosphorus can be preferred in combination with the friction
modifier mixture.
Viscosity Index Improvers
[0069] Viscosity index improvers (also known as VI improvers,
viscosity modifiers, and viscosity improvers) can be included in
the lubricant compositions of this disclosure.
[0070] Viscosity index improvers provide lubricants with high and
low temperature operability. These additives impart shear stability
at elevated temperatures and acceptable viscosity at low
temperatures.
[0071] Suitable viscosity index improvers include high molecular
weight hydrocarbons, polyesters and viscosity index improver
dispersants that function as both a viscosity index improver and a
dispersant. Typical molecular weights of these polymers are between
10,000 to 1,500,000, more typically 20,000 to 1,200,000, and even
more typically between 50,000 and 1,000,000.
[0072] Examples of suitable viscosity index improvers are linear or
star-shaped polymers and copolymers of methacrylate, butadiene,
olefins, or alkylated styrenes. Polyisobutylene is a commonly used
viscosity index improver. Another suitable viscosity index improver
is polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity index improvers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
50,000 to 200,000 molecular weight.
[0073] Olefin copolymers, are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921" and "PARATONE.RTM. 8941"); from Afton
Chemical Corporation under the trade designation "HiTEC.RTM." (such
as "HiTEC.RTM. 5850B"; and from The Lubrizol Corporation under the
trade designation "Lubrizol.RTM. 7067C". Polyisoprene polymers are
commercially available from Infineum International Limited, e.g.
under the trade designation "SV200"; diene-styrene copolymers are
commercially available from Infineum International Limited, e.g.,
under the trade designation "SV 260".
[0074] In an embodiment of this disclosure, the viscosity index
improvers may be used in an amount of less than 2.0 weight percent,
preferably less than 1.0 weight percent, and more preferably less
than 0.5 weight percent, based on the total weight of the
formulated oil or lubricating engine oil. Viscosity improvers are
typically added as concentrates, in large amounts of diluent
oil.
[0075] In another embodiment of this disclosure, the viscosity
index improvers may be used in an amount of from 0.25 to 2,0 weight
percent, preferably 0.15 to 1.0 weight percent, and more preferably
0.05 to 0.5 weight percent, based on the total weight of the
formulated oil or lubricating engine oil.
Detergents
[0076] Illustrative detergents useful in this disclosure include,
for example, alkali metal detergents, alkaline earth metal
detergents, or mixtures of one or more alkali metal detergents and
one or more alkaline earth metal detergents. A typical detergent is
an anionic material that contains a long chain hydrophobic portion
of the molecule and a smaller anionic or oleophobic hydrophilic
portion of the molecule. The anionic portion of the detergent is
typically derived from an organic acid such as a sulfur acid,
carboxylic acid, phosphorous acid, phenol, or mixtures thereof. The
counterion is typically an alkaline earth or alkali metal.
[0077] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased. These detergents can be used in
mixtures of neutral, overbased, highly overbased calcium
salicylate, sulfonates, phenates and/or magnesium salicylate,
sulfonates, phenates. The TBN ranges can vary from low, medium to
high TBN products, including as low as 0 to as high as 600.
Mixtures of low, medium, high TBN can be used, along with mixtures
of calcium and magnesium metal based detergents, and including
sulfonates, phenates, salicylates, and carboxylates. A detergent
mixture with a metal ratio of 1, in conjunction of a detergent with
a metal ratio of 2, and as high as a detergent with a metal ratio
of 5, can be used. Borated detergents can also be used.
[0078] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH).sub.2, BaO, Ba(OH).sub.2,
MgO, Mg(OH).sub.2, for example) with an alkyl phenol or to
sulfurized alkylphenol. Useful alkyl groups include straight chain
or branched C.sub.1-C.sub.30 alkyl groups, preferably,
C.sub.4-C.sub.20 or mixtures thereof. Examples of suitable phenols
include isobutylphenol, 2-ethylhexylphenol, nonylphenol, dodecyl
phenol, and the like. It should be noted that starting alkylphenols
may contain more than one alkyl substituent that are each
independently straight chain or branched and can be used from 0.5
to 6 weight percent. When a non-sulfurized alkylphenol is used, the
sulfurized product may be obtained by methods well known in the
art. These methods include heating a mixture of alkylphenol and
sulfurizing agent (including elemental sulfur, sulfur halides such
as sulfur dichloride, and the like) and then reacting the
sulfurized phenol with an alkaline earth metal base.
[0079] Metal salts of carboxylic acids are also useful as
detergents. These carboxylic acid detergents may be prepared by
reacting a basic metal compound with at least one carboxylic acid
and removing free water from the reaction product. These compounds
may be overbased to produce the desired TBN level. Detergents made
from salicylic acid are one preferred class of detergents derived
from carboxylic acids. Useful salicylates include long chain alkyl
salicylates. One useful family of compositions is of the
formula
##STR00001##
where R is an alkyl group having 1 to 30 carbon atoms, n is an
integer from it to 4, and M is an alkaline earth metal. Preferred R
groups are alkyl chains of at least C.sub.11, preferably C .sub.13
or greater. R may be optionally substituted with substituents that
do not interfere with the detergent's function. M is preferably,
calcium, magnesium, or barium. More preferably, M is calcium.
[0080] Hydrocarbyl-substituted salicylic acids may be prepared from
phenols by the Kolbe reaction (see U.S. Pat. No. 3,595,791). The
metal salts of the hydrocarbyl-substituted salicylic acids may be
prepared by double decomposition of a metal salt in a polar solvent
such as water or alcohol.
[0081] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0082] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039.
[0083] Preferred detergents include calcium phenates, calcium
sulfonates, calcium salicylates, magnesium phenates, magnesium
sulfonates, magnesium salicylates and other related components
(including borated detergents), and mixtures thereof. Preferred
mixtures of detergents include magnesium sulfonate and calcium
salicylate, magnesium sulfonate and calcium sulfonate, magnesium
sulfonate and calcium phenate, calcium phenate and calcium
salicylate, calcium phenate and calcium sulfonate, calcium phenate
and magnesium salicylate, calcium phenate and magnesium
phenate.
[0084] The detergent concentration in the lubricating oils of this
disclosure can range from 1.0 to 6.0 weight percent, preferably 2.0
to 5.0 weight percent, and more preferably from 2.0 weight percent
to 4.0 weight percent, based on the total weight of the lubricating
oil.
[0085] As used herein, the detergent concentrations are given on an
"as delivered" basis. Typically, the active detergent is delivered
with a process oil. The "as delivered" detergent typically contains
from 20 weight percent to 80 weight percent, or from 40 weight
percent to 60 weight percent, of active detergent in the "as
delivered" detergent product.
Dispersants
[0086] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
used in the formulation of the lubricating oil may be ashless or
ash-forming in nature. Preferably, the dispersant is ashless.
So-called is ashless dispersants are organic materials that form
substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0087] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorus. Typical hydrocarbon chains contain
50 to 400 carbon atoms.
[0088] A particularly useful class of dispersants are the
alkenylsuccinic derivatives, typically produced by the reaction of
a long chain hydrocarbyl substituted succinic compound, usually a
hydrocarbyl substituted succinic anhydride, with a polyhydroxy or
polyamino compound. The long chain hydrocarbyl group constituting
the oleophitic portion of the molecule which confers solubility in
the oil, is normally a polyisobutylene group. Many examples of this
type of dispersant are well known commercially and in the
literature. Exemplary U.S. patents describing such dispersants are
U.S. Pat. Nos. 3,172,892; 3,215,707; 3,219,666; 3,316,177;
3,341,542; 3,444,170; 3,454,607; 3,541,012; 3,630,904; 3,632,511;
3,787,374 and 4,234,435. Other types of dispersant are described in
U.S. Pat. Nos. 3,036,003; 3,200,107; 3,254,025; 3,275,554;
3,438,757; 3,454,555; 3,565,804; 3,413,347; 3,697,574; 3,725,277;
3,725,480; 3,726,882; 4,454,059; 3,329,658; 3,449,250; 3,519,565;
3,666,730; 3,687,849; 3,702,300; 4,100,082; 5,705,458. A further
description of dispersants may be found, for example, in European
Patent Application No. 471 071 to which reference is made for this
purpose.
[0089] Hydrocarbyl-substituted succinic acid and
hydrocarbyl-substituted succinic anhydride derivatives are useful
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful,
although on occasion, having a hydrocarbon substituent between
20-50 carbon atoms can be useful.
[0090] Succinimides are formed by the condensation reaction between
hydrocarbyl substituted succinic anhydrides and amines. Molar
ratios can vary depending on the polyamine. For example, the molar
ratio of hydrocarbyl substituted succinic anhydride to TEPA can
vary from 1:1 to 5:1. Representative examples are shown in U.S.
Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746; 3,322,670;
and 3,652,616, 3,948,800; and Canada Patent No. 1,094,044.
[0091] Succinate esters are formed by the condensation reaction
between hydrocarbyl substituted succinic anhydrides and alcohols or
polyols. Molar ratios can vary depending on the alcohol or polyol
used. For example, the condensation product of a hydrocarbyl
substituted succinic anhydride and pentaerythritol is a useful
dispersant.
[0092] Succinate ester amides are formed by condensation reaction
between hydrocarbyl substituted succinic anhydrides and alkanol
amines. For example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0093] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500 or more. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid. The above
products can also be post reacted with boron compounds such as
boric acid, borate esters or highly borated to dispersants, to form
borated dispersants generally having from 0.1 to 5 moles of boron
per mole of dispersant reaction product.
[0094] Mannich base dispersants are made from the reaction of alkyl
phenols, formaldehyde, and amines. See U.S. Pat. No. 4,767,551,
which is incorporated herein by reference. Process aids and
catalysts, such as oleic acid and sulfonic acids, can also be part
of the reaction mixture. Molecular weights of the alkylphenols
range from 800 to 2,500. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0095] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this disclosure can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HNR.sub.2 group-containing reactants.
[0096] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197.
[0097] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
500 to 5000, or from 1000 to 3000, or 1000 to 2000, or a mixture of
such hydrocarbylene groups, often with high terminal vinylic
groups. Other preferred dispersants include succinic acid-esters
and amides, alkylphenol-polyamine-coupled Mannich adducts, their
capped derivatives, and other related components. Such additives
may be used in an amount of 0.1 to 20 weight percent, preferably
0.5 to 8 weight percent, or more preferably 0.5 to 4 weight
percent. On an active ingredient basis, such additives may be used
in an amount of 0.06 to 14 weight percent, preferably 0.3 to 6
weight percent. The hydrocarbon portion of the dispersant atoms can
range from C.sub.60 to C.sub.400, or from C.sub.70 to C.sub.300, or
from C.sub.70 to C.sub.200. These dispersants may contain both
neutral and basic nitrogen, and mixtures of both. Dispersants can
be end-capped by borates and/or cyclic carbonates.
[0098] As used herein, the dispersant concentrations are given on
an "as delivered" basis. Typically, the active dispersant is
delivered with a process oil. The "as delivered" dispersant
typically contains from 20 weight percent to 80 weight percent, or
from 40 weight percent to 60 weight percent, of active dispersant
in the "as delivered" dispersant product.
Antioxidants
[0099] Antioxidants retard the oxidative degradation of base oils
during service. Such degradation may result in deposits on metal
surfaces, the presence of sludge, or a viscosity increase in the
lubricant. One skilled in the art knows a wide variety of oxidation
inhibitors that are useful in lubricating oil compositions. See,
Klamann in Lubricants and Related Products, op cite, and U.S. Pat.
Nos. 4,798,684 and 5,084,197, for example.
[0100] Useful antioxidants include hindered phenols. These phenolic
antioxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones which contain a sterically hindered hydroxyl group, and
these include those derivatives of dihydroxy aryl compounds in
which the hydroxyl groups are in the o- or p-position to each
other. Typical phenolic antioxidants include the hindered phenols
substituted with C.sub.6+ alkyl groups and the alkylene coupled
derivatives of these hindered phenols. Examples of phenolic
materials of this type 2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl
phenol; 2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also he advantageously used in
combination with the instant disclosure. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0101] Effective amounts of one or more catalytic antioxidants may
also be used. The catalytic antioxidants comprise an effective
amount of a) one or more oil soluble polymetal organic compounds;
and, effective amounts of b) one or more substituted
N,N'-diaryl-o-phenylenediamine compounds or c) one or more hindered
phenol compounds; or a combination of both b) and c). Catalytic
antioxidants are more fully described in U.S. Pat. No. 8,048,833,
herein incorporated by reference in its entirety.
[0102] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R.sup.8R.sup.9R.sup.10N
where R.sup.8 is an aliphatic, aromatic or substituted aromatic
group, R.sup.9 is an aromatic or a substituted aromatic group, and
R.sup.10 is H, alkyl, aryl or R.sup.11S(O).sub.XR.sup.12 where
R.sup.11 is an alkylene, alkenylene, or aralkylene group, R.sup.12
is a higher alkyl group, or an alkenyl, aryl, or alkaryl group, and
x is 0, 1 or 2. The aliphatic group R.sup.8 may contain from 1 to
20 carbon atoms, and preferably contains from 6 to 12 carbon atoms.
The aliphatic group is a saturated aliphatic group. Preferably,
both R.sup.8 and R9 are aromatic or substituted aromatic groups,
and the aromatic group may be a fused ring aromatic group such as
naphthyl. Aromatic groups R.sup.8 and R.sup.9 may be joined
together with other groups such as S.
[0103] Typical aromatic amines antioxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 14 carbon atoms. The
general types of amine antioxidants useful in the present
compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present disclosure
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0104] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also to are useful antioxidants.
[0105] Preferred antioxidants include hindered phenols, arylamines.
These antioxidants may be used individually by type or in
combination with one another. Such additives may be used in an
amount of 0.01 to 5 weight percent, preferably 0.01 to 1.5 weight
percent, more preferably zero to less than 1.5 weight percent, more
preferably zero to less than 1 weight percent.
Pour Point Depressants (PPDs)
[0106] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
disclosure if desired. These pour point depressant may be added to
lubricating compositions of the present disclosure to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Such additives may be
used in an amount of 0.01 to 5 weight percent, preferably 0.01 to
1.5 weight percent.
Seal Compatibility Agents
[0107] Seal compatibility agents help to swell elastomeric seals by
causing a chemical reaction in the fluid or physical change in the
elastomer. Suitable seal compatibility agents for lubricating oils
include organic phosphates, alkoxysulfonlanes (C.sub.10 alcohol,
for example), aromatic esters, aromatic hydrocarbons, esters
(butylbenzyl phthalate, for example), and polybutenyl succinic
anhydride. Such additives may be used in an amount of 0.01 to 3
weight percent, preferably 0.01 to 2 weight percent.
Antifoam Agents
[0108] Antifoam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical antifoam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Antifoam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 weight
percent and often less than 0.1 weight percent.
Inhibitors and Antirust Additives
[0109] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. A wide variety of these are
commercially available.
[0110] One type of antirust additive is a polar compound that wets
the metal surface preferentially, protecting it with a film of oil.
Another type of antirust additive absorbs water by incorporating it
in a water-in-oil emulsion so that only the oil touches the metal
surface. Yet another type of antirust additive chemically adheres
to the metal to produce a non-reactive surface. Examples of
suitable additives include zinc dithiophosphates, metal phenolates,
basic metal sulfonates, fatty acids and amines. Such additives may
be used in an amount of 0.01 to 5 weight percent, preferably 0.01
to 1.5 weight percent.
Organic Metallic Friction Modifiers
[0111] In addition to the friction modifier mixtures used in the
lubricating engine oil formulations of this disclosure, organic
metallic friction modifiers may also be used. Organic metallic
friction modifiers useful in this disclosure are any materials that
can alter the coefficient of friction of a surface lubricated by
any lubricant or fluid containing such material(s). Organic
metallic friction modifiers, also known as friction reducers, or
lubricity agents or oiliness agents, and other such agents that
change the ability of base oils, formulated lubricant compositions,
or functional fluids, to modify the coefficient of friction of a
lubricated surface can be effectively used in combination with the
base oils or lubricant compositions of the present disclosure.
Organic metallic friction modifiers that lower the coefficient of
friction are particularly advantageous in combination with the base
oils and lube compositions of this disclosure.
[0112] Illustrative organic metallic friction modifiers useful in
the lubricating engine oil formulations of this disclosure include,
for example, molybdenum amine, is molybdenum diamine, an
organotungstenate, a molybdenum dithiocarbamate, molybdenum
dithiophosphates, molybdenum amine complexes, molybdenum
carboxylates, and the like. Similar tungsten based compounds may be
preferable. Useful concentrations of the organic metallic friction
modifiers may range from 0.01 weight percent to 5 weight percent,
or 0.1 weight percent to 2.5 weight percent. Useful concentration
of molybdenum can range from 25 to 700 ppm, or more preferably from
50 to 200 ppm.
[0113] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 1 below.
[0114] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating oil composition.
TABLE-US-00002 TABLE 1 Typical Amounts of Other Lubricating Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Dispersant 0.1-20 0.1-8 Detergent 0.1-20 0.1-8 Friction
Modifier 0.01-5 0.01-1.5 Antioxidant 0.1-5 0.1-1.5 Pour Point
Depressant 0.0-5 0.01-1.5 (PPD) Anti-foam Agent 0.001-3 0.001-0.15
Viscosity Index Improver 0.1-2 0.1-1 (solid polymer basis)
Anti-wear 0.1-2 0.5-1 Inhibitor and Antirust 0.01-5 0.01-1.5
[0115] The foregoing additives are all commercially available
materials. These additives may be added independently but are
usually precombined in packages which can be obtained from
suppliers of lubricant oil additives. Additive packages with a
variety of ingredients, proportions and characteristics are
available and selection of the appropriate package will take the
requisite use of the ultimate composition into account.
[0116] The following examples are provided to illustrate the
disclosure.
EXAMPLE
[0117] The detergents used in the formulations were a petroleum
derived calcium sulfonate, a synthetic calcium sulfonate, a neutral
calcium salicylate, an overbased calcium salicylate, a mixed
calcium salicylate, and a magnesium sulfonate.
[0118] The friction modifiers used in the formulations included
organic friction modifiers and organic metallic friction modifiers.
The organic friction modifiers were an ethoxylated fatty ester and
a mixed glyceride ester (mono, di and tri glyceride), mostly
C.sub.14, C.sub.16 and C.sub.18, saturated. The organic metallic
friction modifier was a molybdenum dithiocarbamate that was held
constant for a majority of the formulations.
[0119] The antioxidants used in the formulations were a methylene
bridged bis-hindered phenol and a alkylated diphenyl amine.
[0120] Bench testing was conducted for formulations of this
disclosure. The bench testing included the following: kinematic
viscosity (KY) at 100.degree. C. measured by ASTM D445; integrated
mini traction machine (MTM) friction at 140.degree. C. measured as
described below; and thermo-oxidation engine oil simulation (TEOST
33C) measured by ASTM D6335. For the formulations identified in
FIG. 1, the bench testing also included high temperature high shear
(HTHS) viscosity at 150.degree. C. measured by ASTM D4683.
[0121] The Mini Traction Machine (MTM) is a fully automated
instrument manufactured by PCS Instruments and identified as Model
MTM. The test specimens and apparatus configuration are such that
realistic pressure, temperature and speed can be attained without
requiring very large loads, motors or structures. A small sample of
fluid (50 milliliters) is placed in a test cell and the machine
automatically runs either through a range of speeds, slide-to-roll
ratios, temperatures and loads, or at specifically set temperature,
slide-to-roll ratio and speed range to generate information
regarding the friction performance of a test fluid without further
operator intervention. The working of the MTM is known and familiar
to those of skill in the art.
[0122] PCMO (passenger car motor oil) formulations were prepared.
FIG. 1 provides formulation details in weight percent based on the
total weight percent of the formulation. A synthetic oil was used
as baseline and contained both organic metallic and organic
friction modifiers to allow for comparison of the different
chemistries. Additional cleanliness and average integrated MTM
Stribeck friction data were also collected on oil containing only
organic metallic friction modifier. Comparative Example 3, as well
as no friction modifier. Comparative Example 2, to provide a
reference. All other components were the same across all three
blends with the differences being made up by base oil. FIG. 1
summarizes the three oils considered baseline comparison oils for
the 0W-20 oils of this disclosure and their respective TEOST 33C
and average integrated friction coefficient from MTM Stribeck
measurements at 140.degree. C.
[0123] In order to allow for numerical comparison of the MTM
Stribeck traces, an integration method (the trapezoidal rule) was
employed for each curve individually and an average integrated
Stribeck friction coefficient and standard deviation for all 4
traces, run back-to-back, was calculated. The average integrated
Stribeck friction coefficient provides a measure of the friction an
engine will see during operation (albeit at different ratios to
those calculated). The MTM integrated area value listed in this
disclosure has been calculated using this method.
Combination of Ethoxylated Fatty Ester and Mixed Glyceride
Ester
[0124] A MTM Stribeck friction treat rate study was undertaken and
the results are shown in FIG. 2, indicating that the lowest MTM
friction observed was achieved using only ethoxylated fatty ester
(red diamonds) in the formulation. Use of ethoxylated fatty ester
as a toptreat (blue diamonds) to the baseline formulation also
decreased MTM friction versus the baseline formulations, but not as
much as for the blends with only ethoxylated fatty ester. The total
deposits formed also increased.
[0125] Additionally, to highlight the reduction in friction
performance with ethoxylated fatty ester, FIG. 3 shows a comparison
of the MTM performance for the baseline oil with mixed glyceride
ester and an organic metallic friction modifier versus that of a
blend with a 1% treat of ethoxylated. fatty ester and no mixed
glyceride ester or an organic metallic friction modifier. Several
unexpected performance features are displayed in FIG. 3. First, the
average Stribeck friction coefficient for the first four traces is
1/6.sup.th of the 0W-20 baseline comparison (4.sup.th trace of
baseline oil shown in light blue). Second, the very low first trace
indicate that ethoxylated fatty ester is fast-acting. Third, over
10 MTM traces, the ethoxylated fatty ester containing oil continues
to build friction, whereas the baseline oil stabilizes after 4-6
traces (not shown), albeit at a significantly higher coefficient of
friction. Finally, the ethoxylated fatty ester traces have a
defined coefficient of friction structure as a function of speed,
confirming the unexpected friction benefits. The addition of
ethoxylated fatty ester is clearly shown to have significant
friction benefits compared to the baseline with mixed glyceride
ester and metal containing organic complex.
[0126] Building from the above bench scale work, an engine test oil
was developed with 1% ethoxylated fatty ester and an organic
metallic friction modifier, but no other friction modifier, and run
in the Sequence VID Fuel Economy (ASTM D7589) engine to test. The
FEI sum for the test oil was 2.9%, an increase over the Sequence
VID result for the baseline formulation of 2.6%, showing that the
reduced friction seen in the MTM can be translated in an engine
test.
[0127] While ethoxylated fatty ester has reduced the MTM friction
and increased the Sequence VID FEI sum, there is an increase in
deposits with ethoxylated fatty ester. FIG. 4 shows the TEOST 33C
performance for a number of blends with ethoxylated fatty ester,
mixed glyceride ester, or a combination of both. The formulation
with only ethoxylated fatty ester, Comparative Example 5, had 43 mg
of deposit, which is unacceptable versus the GF-5 limit of 30 mg
and versus the 28 mg result for oil with only mixed glyceride
ester, Comparative Example 4.
[0128] FIG. 4 shows multiple formulation changes which were made to
reduce the TEOST 33C deposits with minimal impact on the friction
reduction benefit for ethoxylated fatty ester. Mixing 0.2% mixed
glyceride ester with ethoxylated fatty ester at an unchanged treat,
Inventive Example 1, the friction surprising improves, while the
TEOST 33C result reduces to 30 mg, which is at the industry limit
and can be considered equivalent to Comparative Example 4. The MTM
results show that the friction is reduced with the combination of
ethoxylated fatty ester and mixed glyceride ester versus the
performance of the baseline formulation, Inventive Example 1 thus
shows that the use of mixed friction modifier chemistries is
unexpectedly used to improve deposits, while maintaining or
reducing friction.
[0129] Other modifications shown in FIG. 4, Inventive Example 2,
improve TEOST 33C performance compared to Comparative Example 4 and
Comparative Example 5. While these modifications, such as an
increase in overbased detergent or dispersant, are expected to have
a significant detrimental impact on MTM friction performance,
Inventive Example 2 shows that they surprisingly maintain the same
level of friction benefit obtained in Inventive Example 1.
[0130] The above results show that the combination of ethoxylated
fatty ester and mixed glyceride ester can provide improved fuel
economy performance by reducing friction with no debit in deposit
control.
[0131] FIG. 5 shows formulation details in weight percent based on
the total weight percent of the formulation, of various
formulations. FIG. 5 also shows the results of bench testing of the
formulations using then no-oxidation engine oil simulation TEOST
33C and MTM friction coefficient. As can be seen in FIG. 5, the
concentrations in weight percent of the friction modifiers
(ethoxylated fatty ester and mixed glyceride ester) vary from blend
to blend while the weight percent of the remaining ingredients
remains the same. The results show that formulations with
ethoxylated fatty ester and mixed glyceride ester concentrations
ranging from 0.1 wt % to 1.0 wt % (while the other is being held
constant), exhibit good friction reduction and deposit control
properties, as shown in Inventive Example 3 through Inventive
Example 18, Additionally, Inventive Examples 19 and Inventive
Example 20 highlight the impact of using Group I and Group II base
stocks, with Group I being more beneficial, instead of a mixture of
Group II, III, IV, V, on the friction and deposit bench test
results.
[0132] The components and base stocks used in the exemplary
formulations of FIG. 6 are set forth therein. All of the
ingredients are commercially available.
[0133] The detergent used in the formulations was an overbased
calcium salicylate.
[0134] The friction modifiers used in the formulations included
organic friction modifiers. The organic friction modifiers were an
ethoxylated fatty ester and a mixed glyceride ester. An organic
metallic friction modifier (i.e., molybdenum dithiocarbamate) was
also used in the formulations.
[0135] PIB dispersants, antioxidants, antiwear agents, and pour
point depressants were also used in the formulations.
[0136] FIG. 6 shows formulation details in weight percent based on
the total weight percent of the formulation, of various
formulations. FIG. 6 also shows the results of bench testing of the
formulations using thermo-oxidation engine oil simulation (TEOST
33C) measured by ASTM D6335 and MTM friction. As can be seen in
FIG. 6, the concentrations in weight percent of the PIB dispersant
and detergent vary from blend to blend while the weight percent of
the remaining ingredients remains the same. Inventive Examples 21
through Inventive Example 28 demonstrate that a treatment of
overbased calcium salicylate detergent of from 0.5 wt % to 2,5 wt
%, and a treatment of PIB dispersant of from 2.0 wt % to 5.0 wt %
may be used in combination with the mixed friction modifier
chemistries to achieve deposit and/or friction benefits.
[0137] The components and base stocks used in the exemplary
formulations of FIG. 6 are set forth therein and are the same as in
FIG. 5. All of the ingredients are commercially available.
Other Exemplary Formulations
[0138] The lubricating engine oil formulations in FIG. 7 are
combinations of additives and base stocks and are expected to have
kinematic viscosity at 100.degree. C. around 6 cSt and high
temperature high shear (10.sup.-6 s.sup.-1) viscosity at
150.degree. C. around 2.0 cP. The lubricating engine oil
formulations of Examples 1, 2, 3, 4, and 5 are expected to have
phosphorus levels around 650 ppm, while Example 6 will have around
350 ppm phosphorus and Example 7 will have around 1300 ppm
phosphorus. The lubricating engine oil formulations of Examples 1,
4, 5, 6, 7 are expected to have molybdenum levels around 800 ppm
while Example 2 will have around 0 ppm of molybdenum and Example 3
will have around 275 ppm of molybdenum. The lubricant formulations
of Examples 1, 2, 3, 6, 7 are expected to have TBN values around 9
while Example 4 will have a TBN value of around 6 and Example 5
will have a TBN value of around 15. The lubricant formulations of
Examples 1, 2, 3, 6, 7 are expected to have ash levels around 0.95%
while the formulations in example 5 will have around 0.6% ash and
example 6 will have around 1.6% ash.
[0139] The lubricating engine oil formulations in FIG. 8 are
combinations of additives and base stocks and are expected to have
kinematic viscosities at 100.degree. C. of around 8 cSt and high
temperature high shear (10.sup.6 s.sup.-1) viscosity at 150.degree.
C. of around 2.6 cP. The lubricating engine oil formulations of
Examples 8, 9, 10, 11, 12 are expected to have phosphorus levels of
around 650ppm while Example 13 will have around 350 ppm Phosphorus
and Example 14 will have around 1300 ppm Phosphorus. The
lubricating engine oil formulations of Examples 8, 11, 12, 13, 14
are expected to have molybdenum levels of around 800 ppm while
Example 9 will have around 0 ppm of molybdenum and Example 10 will
have around 275 ppm of molybdenum. The lubricant formulations of
Examples 8, 9, 10, 13, 14 are expected to have TBN values of is
around 9 while Example 11 will have a TBN value of around 6 and
Example 12 will have a TBN value of around 15. The lubricant
formulations of Examples 8, 9, 10, 13, 14 are expected to have ash
levels of around 0.95% while the formulations in example 11 will
have around 0.6% ash and example 12 will have around 1.6% ash.
[0140] The lubricating engine oil formulations in FIG. 9 are
combinations of additives and base stocks and are expected to have
kinematic viscosity at 100.degree. C. around 10 cSt and high
temperature high shear (10.sup.-6 s.sup.-1) viscosity at
150.degree. C. of around 3.0 cP. The lubricating engine oil
formulations of Examples 15, 16, 17, 18, 19 are expected to have
phosphorus levels of around 650 ppm while Example 20 will have
around 350 ppm phosphorus and Example 21 will have around 1300 ppm
phosphorus. The lubricating engine oil formulations of Examples 15,
18, 19, 20, 21 are expected to have molybdenum levels of around 800
ppm while Example 16 will have around 0 ppm of molybdenum and
Example 17 will have around 275 ppm of molybdenum. The lubricant
formulations of Examples 15, 16, 17, 20, 21 are expected to have
TBN values of around 9 while Example 18 will have a TBN value of
around 6 and Example 19 will have a TBN value of around 15. The
lubricant formulations of Examples 15, 16, 17, 20, 21 are expected
to have ash levels of around 0.95% while the formulations in
example 18 will have around 0% ash and example 19 will have around
1.6% ash.
[0141] All patents and patent applications, test procedures (such
as ASTM methods, UL methods, and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this disclosure and for all
jurisdictions in which such incorporation is permitted.
[0142] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present is disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0143] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *
References