U.S. patent application number 12/724449 was filed with the patent office on 2010-11-18 for lubricant formulations and methods.
This patent application is currently assigned to AFTON CHEMICAL CORPORATION. Invention is credited to Mark T. DEVLIN, Jeffrey M. GUEVREMONT, Jason A. LAGONA, Naresh C. MATHUR.
Application Number | 20100292113 12/724449 |
Document ID | / |
Family ID | 42727578 |
Filed Date | 2010-11-18 |
United States Patent
Application |
20100292113 |
Kind Code |
A1 |
GUEVREMONT; Jeffrey M. ; et
al. |
November 18, 2010 |
LUBRICANT FORMULATIONS AND METHODS
Abstract
The embodiments described herein relate to particular
formulations and methods that may provide improved fuel economy
characteristics for an engine lubricant. The compositions and
methods include a (a) a base oil; (b) a zinc dialkyldithiophosphate
compound; and (c) a hydrocarbon soluble metal compound. The
hydrocarbon soluble metal compound is devoid of phosphorus and
sulfur atoms and the metal is selected from the group consisting
essentially of selected from the group consisting essentially of
cobalt, nickel, zinc, zirconium, manganese, vanadium, scandium,
yttrium, tungsten, gold, platinum, and iron. A weight ratio of
total metal in the lubricant composition from the zinc
dialkyl-dithiophosphate compound and the hydrocarbon soluble metal
compound to phosphorus in the lubricant composition ranges from
greater than about 1.5 to 1 to about 15 to 1.
Inventors: |
GUEVREMONT; Jeffrey M.;
(Richmond, VA) ; DEVLIN; Mark T.; (Richmond,
VA) ; MATHUR; Naresh C.; (Midlothian, VA) ;
LAGONA; Jason A.; (Richmond, VA) |
Correspondence
Address: |
AFTON CHEMICAL CORPORATION;LUEDEKA, NEELY & GRAHAM, PC
P.O. BOX 1871
KNOXVILLE
TN
37901
US
|
Assignee: |
AFTON CHEMICAL CORPORATION
Richmond
VA
|
Family ID: |
42727578 |
Appl. No.: |
12/724449 |
Filed: |
March 16, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61178545 |
May 15, 2009 |
|
|
|
Current U.S.
Class: |
508/369 |
Current CPC
Class: |
C10M 2203/1006 20130101;
C10M 141/10 20130101; C10N 2070/02 20200501; C10M 2223/045
20130101; C10M 2227/09 20130101; C10N 2030/43 20200501; C10N
2030/42 20200501; C10N 2030/06 20130101; C10N 2030/56 20200501;
C10N 2030/70 20200501; C10M 2203/1025 20130101; C10N 2040/25
20130101; C10M 2207/08 20130101; C10M 2205/0285 20130101; C10M
163/00 20130101; C10N 2030/45 20200501; C10N 2030/54 20200501; C10M
2203/1025 20130101; C10N 2020/02 20130101; C10M 2223/045 20130101;
C10N 2010/04 20130101; C10M 2203/1025 20130101; C10N 2020/02
20130101; C10M 2223/045 20130101; C10N 2010/04 20130101 |
Class at
Publication: |
508/369 |
International
Class: |
C10M 137/10 20060101
C10M137/10 |
Claims
1. A lubricant composition for providing improved friction
characteristics: (a) a base oil; (b) a zinc dialkyldithiophosphate
compound; and (c) a hydrocarbon soluble metal compound, wherein the
hydrocarbon soluble metal compound is devoid of phosphorus and
sulfur atoms and the metal is selected from the group consisting
essentially of cobalt, nickel, zinc, zirconium, manganese,
vanadium, scandium, yttrium, tungsten, gold, platinum, and iron,
wherein a weight ratio of total metal in the lubricant composition
from the zinc dialkyl-dithiophosphate compound and the hydrocarbon
soluble metal compound to phosphorus in the lubricant composition
ranges from greater than about 1.5 to 1 to about 15 to 1.
2. The lubricant composition of claim 1, wherein the lubricant
composition is an engine oil.
3. The lubricant composition of claim 1, wherein the lubricant
composition is a heavy duty engine oil.
4. The lubricant composition of claim 1, wherein the base oil
comprises a mineral oil, a synthetic oil, or a mixture thereof.
5. The lubricant composition of claim 1, wherein the base oil
comprises on or more of a member selected from the group consisting
of: a group I base oil, a group II base oil, a group III base oil,
a group IV base oil, and a group V base oil.
6. The lubricant composition of claim 1, wherein a total amount of
metal in the lubricant composition from the zinc
dialkyldithiophosphate compound and the hydrocarbon soluble metal
compound ranges from about 300 to about 1500 ppm by weight based on
the total weight of the lubricant composition.
7. The lubricant composition of claim 1, wherein a total amount of
phosphorus in the lubricant composition from the zinc
dialkyldithiophosphate compound ranges from about 200 to about 1000
ppm by weight based on the total weight of the lubricant
composition.
8. The lubricant composition of claim 1, wherein a boundary
friction characteristic at 130.degree. C. is less than a boundary
friction characteristic at 130.degree. C. of a lubricant
composition comprising zinc dialkyldithiophosphate and having a
total metal to phosphorus weight ratio of less than about 1.5 to 1,
wherein the lubricant composition is devoid of the hydrocarbon
soluble metal compound.
9. The lubricant composition of claim 1, wherein a boundary
friction characteristic at 130.degree. C. is less than a boundary
friction characteristic at 130.degree. C. of a lubricant
composition comprising zinc dialkyldithiophosphate, wherein the
lubricant composition is devoid of the hydrocarbon soluble metal
compound.
10. The lubricant composition of claim 1, wherein the weight ratio
of total metal in the lubricant composition from the zinc
dialkyl-dithiophosphate compound and the hydrocarbon soluble metal
compound to phosphorus in the lubricant composition ranges from
greater than about 3.0 to 1 to about 10 to 1.
11. An additive concentrate for an engine crankcase lubricant
comprising: (a) a zinc dialkyldithiophosphate compound; and (b) a
hydrocarbon soluble metal compound other than a dispersant or a
detergent, wherein the hydrocarbon soluble metal compound is devoid
of phosphorus and sulfur atoms and the metal is selected from the
group consisting essentially of cobalt, nickel, zinc, zirconium,
manganese, vanadium, scandium, yttrium, tungsten, gold, platinum,
and iron, wherein a weight ratio of total metal in the concentrate
from the zinc dialkyl-dithiophosphate compound and the hydrocarbon
soluble metal compound to phosphorus in the concentrate ranges from
greater than about 1.5 to 1 to about 15 to 1.
12. The additive concentrate of claim 11, wherein the additive
concentrate provides a total amount of metal from the zinc
dialkyldithiophosphate compound and the hydrocarbon soluble metal
compound to a lubricant composition containing the concentrate
ranging from about 300 to about 1500 ppm by weight based on the
total weight of the lubricant composition.
13. The additive concentrate of claim 11, wherein the additive
concentrate provides a total amount of phosphorus from the zinc
dialkyldithiophosphate compound to a lubricant composition
containing the concentrate ranging from about 200 to about 1000 ppm
by weight based on the total weight of the lubricant
composition.
14. A method for improving a fuel economy of an internal combustion
engine, comprising lubricating the engine with a lubricant
composition comprising: (a) a base oil; (b) a zinc
dialkyldithiophosphate compound; and (b) a hydrocarbon soluble
metal compound other than a dispersant or a detergent, wherein the
hydrocarbon soluble metal compound is devoid of phosphorus and
sulfur atoms and the metal is selected from the group consisting
essentially of cobalt, nickel, zinc, zirconium, manganese,
vanadium, scandium, yttrium, tungsten, gold, platinum, and iron,
wherein a weight ratio of total metal in the concentrate from the
zinc dialkyl-dithiophosphate compound and the hydrocarbon soluble
metal compound to phosphorus in the lubricant composition ranges
from greater than about 1.5 to 1 to about 15 to 1.
15. The method of claim 14, wherein a total amount of metal in the
lubricant composition from the zinc dialkyldithiophosphate compound
and the hydrocarbon soluble metal compound ranges from about 300 to
about 1500 ppm by weight based on the total weight of the lubricant
composition.
16. The method of claim 14, wherein a total amount of phosphorus in
the lubricant composition from the zinc dialkyldithiophosphate
compound ranges from about 200 to about 1000 ppm by weight based on
the total weight of the lubricant composition.
17. The method of claim 14, wherein a boundary friction
characteristic at 130.degree. C. is less than a boundary friction
characteristic at 130.degree. C. of a lubricant composition
comprising zinc dialkyldithiophosphate and having a total metal to
phosphorus weight ratio of less than about 1.5 to 1, wherein the
lubricant composition is devoid of the hydrocarbon soluble metal
compound.
18. A method for improving a friction characteristic of a lubricant
for an internal combustion engine, comprising formulating a
lubricant composition with: (a) a base oil; (b) a zinc
dialkyldithiophosphate compound; and (b) a hydrocarbon soluble
metal compound other than a dispersant or a detergent, wherein the
hydrocarbon soluble metal compound is devoid of phosphorus and
sulfur atoms and the metal is selected from the group consisting
essentially of cobalt, nickel, zinc, zirconium, manganese,
vanadium, scandium, yttrium, tungsten, gold, platinum, and iron,
wherein a weight ratio of total metal in the concentrate from the
zinc dialkyl-dithiophosphate compound and the hydrocarbon soluble
metal compound to phosphorus in the lubricant composition ranges
from greater than about 1.5 to 1 to about 15 to 1.
19. The method of claim 18, wherein a total amount of metal in the
lubricant composition from the zinc dialkyldithiophosphate compound
and the hydrocarbon soluble metal compound ranges from about 300 to
about 1500 ppm by weight based on the total weight of the lubricant
composition.
20. The method of claim 18, wherein a total amount of phosphorus in
the lubricant composition from the zinc dialkyldithiophosphate
compound ranges from about 200 to about 1000 ppm by weight based on
the total weight of the lubricant composition.
21. The method of claim 18, wherein a boundary friction
characteristic at 130.degree. C. is less than a boundary friction
characteristic at 130.degree. C. of a lubricant composition
comprising zinc dialkyldithiophosphate and having a total metal to
phosphorus weight ratio of less than about 1.5 to 1, wherein the
lubricant composition is devoid of the hydrocarbon soluble metal
compound.
Description
TECHNICAL FIELD
[0001] The embodiments described herein relate to particular
formulations and methods that provide improved lubricant
performance for internal combustion engines.
BACKGROUND AND SUMMARY
[0002] For over fifty (50) years automotive engine oils have been
formulated with zinc dialkyldithiophosphate (ZDDP) resulting in low
levels of wear, oxidation, and corrosion. The additive is truly
ubiquitous and found in nearly every modern engine oil. ZDDP may
impart multifunctional performance in the areas of anti-wear,
anti-oxidation, and anti-corrosion and is considered one of the
most cost-effective additives in general use by engine oil
manufacturers and marketers. In general, ZDDP may form a thick
glassy polyphosphate film that is effective to prevent wear between
metal parts of an engine.
[0003] However, while ZDDP may reduce wear, the polyphosphate films
may cause friction to increase between the metal parts thereby
reducing a fuel economy performance of the lubricant in the engine.
In addition, increased levels of phosphorus may poison engine
emission catalyst. Accordingly, there is a need for additives
which, in combination with ZDDP, provide improved friction
properties without increasing the amount of phosphorus compound in
the lubricant that is required for suitable engine wear
performance.
[0004] In view of the above, an embodiments of the disclosure
relate to particular formulations and methods that may provide
improved fuel economy characteristics for an engine lubricant. The
compositions and methods include a (a) a base oil; (b) a zinc
dialkyldithiophosphate compound; and (c) a hydrocarbon soluble
metal compound. The hydrocarbon soluble metal compound is devoid of
phosphorus and sulfur atoms and the metal is selected from the
group consisting essentially of cobalt, nickel, zinc, zirconium,
manganese, vanadium, scandium, yttrium, tungsten, gold, platinum,
and iron. A weight ratio of total metal in the lubricant
composition from the zinc dialkyldithiophosphate compound and the
hydrocarbon soluble metal compound to phosphorus in the lubricant
composition ranges from greater than about 1.5 to 1 to about 15 to
1.
[0005] An embodiment of the disclosure may provide additive
concentrate for an engine crankcase lubricant. The additive
concentrate includes a zinc dialkyldithiophosphate compound, and a
hydrocarbon soluble metal compound other than a dispersant or a
detergent. The hydrocarbon soluble metal compound is devoid of
phosphorus and sulfur atoms and the metal is selected from the
group consisting essentially of cobalt, nickel, zinc, zirconium,
manganese, vanadium, scandium, yttrium, tungsten, gold, platinum,
and iron. A weight ratio of total metal in the concentrate from the
zinc dialkyldithiophosphate compound and the hydrocarbon soluble
metal compound to phosphorus in the concentrate ranges from greater
than about 1.5 to 1 to about 15 to 1.
[0006] Another embodiment of the disclosure provides a method for
improving a fuel economy of an internal combustion engine.
According to the disclosure, the engine is lubricated with a
lubricant composition that includes, (a) a base oil; (b) a zinc
dialkyldithiophosphate compound; and (b) a hydrocarbon soluble
metal compound other than a dispersant or a detergent. The
hydrocarbon soluble metal compound is devoid of phosphorus and
sulfur atoms and the metal is selected from the group consisting
essentially of zinc cobalt, nickel, zinc, zirconium, manganese,
vanadium, scandium, yttrium, tungsten, gold, platinum, and iron. A
weight ratio of total metal in the concentrate from the zinc
dialkyl-dithiophosphate compound and the hydrocarbon soluble metal
compound to phosphorus in the lubricant composition ranges from
greater than about 1.5 to 1 to about 15 to 1.
[0007] Another embodiment of the disclosure provides a method for
improving a friction characteristic of a lubricant for an internal
combustion engine. According to the disclosure, the engine is
lubricated with a lubricant composition that includes, (a) a base
oil; (b) a zinc dialkyldithiophosphate compound; and (b) a
hydrocarbon soluble metal compound other than a dispersant or a
detergent. The hydrocarbon soluble metal compound is devoid of
phosphorus and sulfur atoms and the metal is selected from the
group consisting essentially of cobalt, nickel, zinc, zirconium,
manganese, vanadium, scandium, yttrium, tungsten, gold, platinum,
and iron. A weight ratio of total metal in the concentrate from the
zinc dialkyl-dithiophosphate compound and the hydrocarbon soluble
metal compound to phosphorus in the lubricant composition ranges
from greater than about 1.5 to 1 to about 15 to 1.
[0008] The compositions and methods described may be particularly
suitable for improving boundary friction characteristics of
lubricant compositions containing from about 100 to about 1000 ppm
phosphorus from a zinc dialkyldithiophosphate compound without
adversely affecting thin film friction characteristics of the
lubricant composition. Other features and advantages of the
compositions and methods described herein may be evident by
reference to the following detailed description which is intended
to exemplify aspects of the embodiments without intending to limit
the embodiments described herein.
[0009] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are intended to provide further
explanation of the embodiments disclosed and claimed.
DETAILED DESCRIPTION
[0010] Lubricant compositions according to embodiments described
herein may comprise a base oil; a zinc dialkyldithiophosphate
(ZDDP) compound and a hydrocarbon soluble metal compound, wherein
the metal of the metal compound is a transition metal selected from
cobalt, nickel, zinc, zirconium, manganese, vanadium, scandium,
yttrium, tungsten, gold, platinum, and iron. It is particularly
desirable that the transition metal compound be substantially
devoid of phosphorus and sulfur atoms. The lubricant composition
may also include other hydrocarbon soluble metal compounds, such as
organomolybdenum compounds that are devoid of phosphorus and sulfur
atoms. However, for purposes of this disclosure, the metal to
phosphorus weight ratio is determined on the basis of the ZDDP and
the hydrocarbon soluble transition metal compounds described above.
Lubricant compositions of the disclosure are also substantially
devoid of non-metal containing phosphorus compounds.
[0011] The lubricant compositions may be suitable for use in a
variety of applications, including but not limited to engine oil
applications and/or heavy duty engine oil applications. Examples
may include the crankcase of spark-ignited and compression-ignited
internal combustion engines, automobile and truck engines, marine
and railroad diesel engines, and the like.
[0012] The lubricant compositions may comprise a base oil and one
or more suitable additive components. The additive components may
be combined to form an additive package which is combined with the
base oil. Or, alternatively, the additive components may be
combined directly with the base oil.
Base Oil
[0013] Base oils suitable for use with present embodiments may
comprise one or more oils of lubricating viscosity such as mineral
(or natural) oils, synthetic lubricating oils, vegetable oils, and
mixtures thereof. Such base oils include those conventionally
employed as crankcase lubricating oils for spark-ignited and
compression-ignited internal combustion engines, such as automobile
and truck engines, marine and railroad diesel engines, and the
like. Suitable base oils may have a NOACK volatility of from about
5 to about 15. As another example, suitable base oils may have a
NOACK volatility of from about 10 to about 15. As even further
example, suitable base oils may have a NOACK volatility of from
about 9 to about 13. Base oils are typically classified as Group I,
Group II, Group III, Group IV and Group V, as described in Table 1
below.
TABLE-US-00001 TABLE 1 Group I-V Base Oils Base Oil % Sulfur %
Saturates Viscosity Index Group I >0.03 and/or <90 80-120
Group II .ltoreq.0.03 and/or .gtoreq.90 80-120 Group III
.ltoreq.0.03 and/or .gtoreq.90 .gtoreq.120 Group IV * Group V ** *
Group IV base oils are defined as all polyalphaolefins ** Group V
base oils are defined as all other base oils not included in Groups
I, II, III and IV and may include gas to liquid base oils.
[0014] Lubricating base oils may also include oils made from a waxy
feed. The waxy feed may comprise at least 40 weight percent
n-paraffins, for example greater than 50 weight percent
n-paraffins, and more desirably greater than 75 weight percent
n-paraffins. The waxy feed may be a conventional petroleum derived
feed, such as, for example, slack wax, or it may be derived from a
synthetic feed, such as, for example, a feed prepared from a
Fischer-Tropsch synthesis.
[0015] Non-limiting examples of synthetic base oils include alkyl
esters of dicarboxylic acids, polyglycols and alcohols,
poly-alpha-olefins, including polybutenes, alkyl benzenes, organic
esters of phosphoric acids, polysilicone oils, and alkylene oxide
polymers, interpolymers, copolymers and derivatives thereof where
the terminal hydroxyl groups have been modified by esterification,
etherification, and the like.
[0016] Mineral base oils include, but are not limited to, animal
oils and vegetable oils (e.g., castor oil, lard oil), liquid
petroleum oils and hydrorefined, solvent-treated or acid-treated
mineral lubricating oils of the paraffinic, naphthenic and mixed
paraffinic-naphthenic types. Oils of lubricating viscosity derived
from coal or shale are also useful base oils.
ZDDP Compound
[0017] A primary component of the lubricant composition is a
phosphorus-containing metal compound such as ZDDP. Suitable ZDDPs
may be prepared from specific amounts of primary or secondary
alcohols, or mixtures thereof. For example, the alcohols may be
combined in a ratio of from about 100:0 to about 0:100
primary-to-secondary alcohols. As an even further example, the
alcohols may be combined in a ratio of about 60:40
primary-to-secondary alcohols. An example of a suitable ZDDP may
comprise the reaction product obtained by combining: (i) about 50
to about 100 mol % of about C.sub.1 to about C.sub.18 primary
alcohol; (ii) up to about 50 mol % of about C.sub.3 to C.sub.18
secondary alcohol; (iii) a phosphorus-containing component; and
(iv) a zinc-containing component. As a further example, the primary
alcohol may be a mixture of from about C.sub.1 to about C.sub.18
alcohols. As an even further example, the primary alcohol may be a
mixture of a C.sub.4 and a C.sub.8 alcohol. The secondary alcohol
may also be a mixture of alcohols. As an example, the secondary
alcohol may comprise a C.sub.3-C.sub.6 alcohol. The alcohols may
contain any of branched, cyclic, or straight chains. The ZDDP may
comprise the combination of about 60 mol % primary alcohol and
about 40 mol % secondary alcohol. In the alternative, the ZDDP may
comprise 100 mol % secondary alcohols, or 100 mol % primary
alcohols.
[0018] The phosphorus-containing component used to make the ZDDP
compound may comprise any suitable phosphorus-containing component
such as, but not limited to a phosphorus sulfide. Suitable
phosphorus sulfides may include phosphorus pentasulfide or
tetraphosphorus trisulfide.
[0019] The zinc-containing component used to make the ZDDP compound
may comprise any suitable zinc-containing component such as, but
not limited to zinc oxide, zinc hydroxide, zinc carbonate, zinc
propylate, zinc chloride, zinc propionate, or zinc acetate.
[0020] The reaction product may comprise a resulting mixture,
component, or mixture of components. The reaction product may or
may not include unreacted reactants, chemically bonded components,
products, or polar bonded components.
[0021] The ZDDP compound may be present in an amount sufficient to
contribute from about 0.03 wt % to about 0.15 wt % phosphorus in
the lubricant composition.
Hydrocarbon Soluble Metal Compound
[0022] The hydrocarbon soluble metal compounds that are used in
combination with the ZDDP compound to provide lubricants having
improved friction characteristics may include a wide variety of
transition metal compounds that are soluble in hydrocarbons such as
natural and synthetic lubricating oils. As described above,
suitable transition metals for the hydrocarbon soluble metal
compounds include, but are not limited to cobalt, nickel, zinc,
zirconium, manganese, vanadium, scandium, yttrium, tungsten, gold,
platinum, and iron.
[0023] The metal compounds may be selected from metal alkoxides,
carboxylates, acetylacetonates, amoinocarboxylates,
aminoacetylacetonates, naphthenates, and polymeric derivatives
thereof containing M-O-M linkages, wherein M is the metal of the
metal compound. Desirably, the transition metal compound is
substantially devoid of sulfur and phosphorus atoms. The metal
carboxylates may be derived from carboxylic acids. The carboxylic
acids may be mono-or polycarboxylic acids such as di- or
tricarboxylic acids.
[0024] Monocarboxylic acids include C.sub.1-7 lower acids (acetic,
proprionic, etc.) and higher C.sub.8+ acids (e.g., octanoic,
decanoic, etc.) as well as the fatty acids of about 12-30 carbon
atoms. The neo acids such as neooctanoic and neodecanoic and the
like are also useful.
[0025] Fatty acids are often mixtures of straight and branched
chain acids containing, for example, from 5% to about 30% straight
chain acids and about 70% to about 95% (mole) branched chain acids.
Other commercially available fatty acid mixtures containing much
higher proportions of straight chain acids are also useful.
Mixtures produced from dimerization of unsaturated fatty acids can
also be used.
[0026] Examples of aminocarboxylic acids that may be used to
provide the metal compound include, but not limited to,
ethylenediaminetetraacetic acid (EDTA),
trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA),
ethylenediaminedisuccinic acid (EDDS),
diethylenetriaminepentaacetic acid (DTPA),
triethylenetetraarninehexaacetic acid (TTHA) and ethylenebis
[2(hydroxyphenyl) glycine] (EDDHA).
[0027] Acetylacetonates, tert-butyl acetylacetonates may be used as
the metal compounds. A particularly suitable hydrocarbon soluble
metal compound is a metal chelate with
2,2,6,6-tetramethyl-3,5-heptanedionate ligands.
[0028] The amount of metal compound used in the lubricant
composition in combination with the ZDDP compound is that amount of
compound which is sufficient to provide a total metal content,
based on ZDDP and the metal compound of from about 300 to about
1500 ppm by weight based on the total weight of the lubricant
composition. Accordingly, the weight ratio of total metal to
phosphorus in the lubricant composition, based on the ZDDP and
hydrocarbon soluble transition metal compound may range from above
1.5 to 1 to about 15 to 1 or higher. In another embodiment, the
weight ratio of total metal to phosphorus may range from about 3 to
1 to about 10 to 1.
[0029] The ZDDP compound and transition metal compound mixture
disclosed herein is used in combination with other additives. The
additives are typically blended into the base oil in an amount that
enables that additive to provide its desired function.
Representative effective amounts of the phosphorus-containing and
transition metal compound mixtures and additives, when used in
crankcase lubricants, are listed in Table 2 below. All the values
listed are stated as weight percent active ingredient.
TABLE-US-00002 TABLE 2 Wt. % Wt. % Component (Broad) (Typical)
Dispersant 0.5-10.0 1.0-5.0 Oxidation Inhibitors 0-10.0 0.1-6.0
Metal Detergents 0.1-15.0 0.2-8.0 Corrosion Inhibitor 0-5.0 0-2.0
Antifoaming agent 0-5.0 0.001-0.15 Pour point depressant 0.01-5.0
0.01-1.5 Viscosity modifier 0.01-20.00 0.25-10.0 ZDDP compound
0.1-10.0 0.25-5.0 Transition metal compound 0.05-5.0 0.075-3.0 Base
oil Balance Balance Total 100 100
Dispersant Components
[0030] Dispersants that may be used in an additive package with the
ZDDP and metal compounds include, but are not limited to, ashless
dispersants that have an oil soluble polymeric hydrocarbon backbone
having functional groups that are capable of associating with
particles to be dispersed. Typically, the dispersants comprise
amine, alcohol, amide, or ester polar moieties attached to the
polymer backbone often via a bridging group. Dispersants may be
selected from Mannich dispersants as described in U.S. Pat. Nos.
3,697,574 and 3,736,357; ashless succcinimide dispersants as
described in U.S. Pat. Nos. 4,234,435 and 4,636,322; amine
dispersants as described in U.S. Pat. Nos. 3,219,666, 3,565,804,
and 5,633,326; Koch dispersants as described in U.S. Pat. Nos.
5,936,041, 5,643,859, and 5,627,259, and polyalkylene succinimide
dispersants as described in U.S. Pat. Nos. 5,851,965; 5,853,434;
and 5,792,729.
Oxidation Inhibitor Components
[0031] Oxidation inhibitor may also be used in combination with the
ZDDP and metal compounds in a lubricant additive package. Oxidation
inhibitors or antioxidants reduce the tendency of base stocks to
deteriorate in service which deterioration can be evidenced by the
products of oxidation such as sludge and varnish-like deposits that
deposit on metal surfaces and by viscosity growth of the finished
lubricant. Such oxidation inhibitors include hindered phenols,
sulfurized hindered phenols, alkaline earth metal salts of
alkylphenolthioesters having C.sub.5 to C.sub.12 alkyl side chains,
sulfurized alkylphenols, metal salts of either sulfurized or
nonsulfurized alkylphenols, for example calcium nonylphenol
sulfide, ashless oil soluble phenates and sulfurized phenates,
phosphosulfurized or sulfurized hydrocarbons, phosphorus esters,
metal thiocarbamates, and oil soluble copper compounds as described
in U.S. Pat. No. 4,867,890. Other antioxidants that may be used
include diarylamines, alkylated phenothiazines, sulfurized
compounds, and ashless dialkyldithiocarbamates. Sterically hindered
phenols and mixtures thereof as described in U.S Publication No.
2004/0266630.
[0032] Diarylamine antioxidants include, but are not limited to
diarylamines having the formula:
##STR00001##
wherein R' and R'' each independently represents a substituted or
unsubstituted aryl group having from 6 to 30 carbon atoms.
Illustrative of substituents for the aryl group include aliphatic
hydrocarbon groups such as alkyl having from 1 to 30 carbon atoms,
hydroxy groups, halogen radicals, carboxylic acid or ester groups,
or nitro groups.
[0033] Another class of aminic antioxidants includes phenothiazine
or alkylated phenothiazine having the chemical formula:
##STR00002##
wherein R.sub.1 is a linear or branched C.sub.1 to C.sub.24 alkyl,
aryl, heteroalkyl or alkylaryl group and R.sub.2 is hydrogen or a
linear or branched C.sub.1-C.sub.24 alkyl, heteroalkyl, or
alkylaryl group.
[0034] The sulfur containing antioxidants include, but are not
limited to, sulfurized olefins that are characterized by the type
of olefin used in their production and the final sulfur content of
the antioxidant. High molecular weight olefins, i.e. those olefins
having an average molecular weight of 168 to 351 g/mole, are
preferred. Examples of olefins that may be used include
alpha-olefins, isomerized alpha-olefins, branched olefins, cyclic
olefins, and combinations of these.
[0035] Sulfur sources that may be used in the sulfurization
reaction of olefins include: elemental sulfur, sulfur monochloride,
sulfur dichloride, sodium sulfide, sodium polysulfide, and mixtures
of these added together or at different stages of the sulfurization
process.
[0036] Unsaturated oils, because of their unsaturation, may also be
sulfurized and used as an antioxidant. Examples of oils or fats
that may be used include corn oil, canola oil, cottonseed oil,
grapeseed oil, olive oil, palm oil, peanut oil, coconut oil,
rapeseed oil, safflower seed oil, sesame seed oil, soyabean oil,
sunflower seed oil, tallow, and combinations of these. The
foregoing aminic, phenothiazine, and sulfur containing antioxidants
are described for example in U.S. Pat. No. 6,599,865.
[0037] The ashless dialkyldithiocarbamates which may be used as
antioxidant additives include compounds that are soluble or
dispersable in the additive package. It is also preferred that the
ashless dialkyldithiocarbamate be of low volatility, preferably
having a molecular weight greater than 250 daltons, most preferably
having a molecular weight greater than 400 daltons. Examples of
dialkyldithiocarbamates that may be used are disclosed in the
following patents: U.S. Pat Nos. 5,693,598; 4,876,375; 4,927,552;
4,957,643; 4,885,365; 5,789,357; 5,686,397; 5,902,776; 2,786,866;
2,710,872; 2,384,577; 2,897,152; 3,407,222; 3,867,359; and
4,758,362.
[0038] Organomolybdenum containing compounds used as friction
modifiers may also exhibit antioxidant functionality. U.S. Pat. No.
6,797,677 describes a combination of organomolybdenum compound,
alkylphenothiazine and alkyldiphenylamines for use in finished
lubricant formulations. Examples of suitable molybdenum containing
friction modifiers are described below under friction
modifiers.
[0039] Friction Modifier Components
[0040] A sulfur- and phosphorus-free organomolybdenum compound that
may be used as a friction modifier may be prepared by reacting a
sulfur- and phosphorus-free molybdenum source with an organic
compound containing amino and/or alcohol groups. Examples of
sulfur- and phosphorus-free molybdenum sources include molybdenum
trioxide, ammonium molybdate, sodium molybdate and potassium
molybdate. The amino groups may be monoamines, diamines, or
polyamines The alcohol groups may be mono-substituted alcohols,
diols or bis-alcohols, or polyalcohols. As an example, the reaction
of diamines with fatty oils produces a product containing both
amino and alcohol groups that can react with the sulfur- and
phosphorus-free molybdenum source.
[0041] Examples of sulfur- and phosphorus-free organomolybdenum
compounds include compounds described in the following patents:
U.S. Pat. Nos. 4,259,195; 4,261,843; 4,164,473; 4,266,945;
4,889,647; 5,137,647; 4,692,256; 5,412,130; 6,509,303; and
6,528,463.
[0042] Molybdenum compounds prepared by reacting a fatty oil,
diethanolamine, and a molybdenum source as described in U.S. Pat.
No. 4,889,647 are sometimes illustrated with the following
structure, where R is a fatty alkyl chain, although the exact
chemical composition of these materials is not fully known and may
in fact be multi-component mixtures of several organomolybdenum
compounds.
##STR00003##
[0043] Sulfur-containing organomolybdenum compounds may be used and
may be prepared by a variety of methods. One method involves
reacting a sulfur and phosphorus-free molybdenum source with an
amino group and one or more sulfur sources. Sulfur sources can
include for example, but are not limited to, carbon disulfide,
hydrogen sulfide, sodium sulfide and elemental sulfur.
Alternatively, the sulfur-containing molybdenum compound may be
prepared by reacting a sulfur-containing molybdenum source with an
amino group or thiuram group and optionally a second sulfur
source
[0044] Examples of sulfur-containing organomolybdenum compounds
include compounds described in the following patents: U.S. Pat.
Nos. 3,509,051; 3,356,702; 4,098,705; 4,178,258; 4,263,152;
4,265,773; 4,272,387; 4,285,822; 4,369,119; 4,395,343; 4,283,295;
4,362,633; 4,402,840; 4,466,901; 4,765,918; 4,966,719; 4,978,464;
4,990,271; 4,995,996; 6,232,276; 6,103,674; and 6,117,826.
[0045] Glycerides may also be used alone or in combination with
other friction modifiers. Suitable glycerides include glycerides of
the formula:
##STR00004##
wherein each R is independently selected from the group consisting
of H and C(O)R' where R' may be a saturated or an unsaturated alkyl
group having from 3 to 23 carbon atoms. Examples of glycerides that
may be used include glycerol monolaurate, glycerol monomyristate,
glycerol monopalmitate, glycerol monostearate, and mono-glycerides
derived from coconut acid, tallow acid, oleic acid, linoleic acid,
and linolenic acids. Typical commercial monoglycerides contain
substantial amounts of the corresponding diglycerides and
triglycerides. These materials are not detrimental to the
production of the molybdenum compounds, and may in fact be more
active. Any ratio of mono- to di-glyceride may be used, however, it
is preferred that from 30 to 70% of the available sites contain
free hydroxyl groups (i.e., 30 to 70% of the total R groups of the
glycerides represented by the above formula are hydrogen). A
preferred glyceride is glycerol monooleate, which is generally a
mixture of mono, di, and tri-glycerides derived from oleic acid,
and glycerol.
Other Additives
[0046] Rust inhibitors selected from the group consisting of
nonionic polyoxyalkylene polyols and esters thereof,
polyoxyalkylene phenols, and anionic alkyl sulfonic acids may be
used.
[0047] A small amount of a demulsifying component may be used. A
preferred demulsifying component is described in EP 330,522. Such
demulsifying component may be obtained by reacting an alkylene
oxide with an adduct obtained by reacting a bis-epoxide with a
polyhydric alcohol. The demulsifier should be used at a level not
exceeding 0.1 mass % active ingredient. A treat rate of 0.001 to
0.05 mass % active ingredient is convenient.
[0048] Pour point depressants, otherwise known as lube oil flow
improvers, lower the minimum temperature at which the fluid will
flow or can be poured. Such additives are well known. Typical of
those additives which improve the low temperature fluidity of the
fluid are C.sub.8 to C.sub.18 dialkyl fumarate/vinyl acetate
copolymers, polyalkylmethacrylates and the like.
[0049] Foam control can be provided by many compounds including an
antifoamant of the polysiloxane type, for example, silicone oil or
polydimethyl siloxane.
[0050] Seal swell agents, as described, for example, in U.S. Patent
Nos. 3,794,081 and 4,029,587, may also be used.
[0051] Viscosity modifiers (VM) function to impart high and low
temperature operability to a lubricating oil. The VM used may have
that sole function, or may be multifunctional.
[0052] Multifunctional viscosity modifiers that also function as
dispersants are also known. Suitable viscosity modifiers are
polyisobutylene, copolymers of ethylene and propylene and higher
alpha-olefins, polymethacrylates, polyalkylmethacrylates,
methacrylate copolymers, copolymers of an unsaturated dicarboxylic
acid and a vinyl compound, inter polymers of styrene and acrylic
esters, and partially hydrogenated copolymers of styrene/isoprene,
styrene/butadiene, and isoprene/butadiene, as well as the partially
hydrogenated homopolymers of butadiene and isoprene and
isoprene/divinylbenzene.
[0053] Functionalized olefin copolymers that may be used include
interpolymers of ethylene and propylene which are grafted with an
active monomer such as maleic anhydride and then derivatized with
an alcohol or amine. Other such copolymers are copolymers of
ethylene and propylene which are grafted with nitrogen
compounds.
[0054] Each of the foregoing additives, when used, is used at a
functionally effective amount to impart the desired properties to
the lubricant. Thus, for example, if an additive is a corrosion
inhibitor, a functionally effective amount of this corrosion
inhibitor would be an amount sufficient to impart the desired
corrosion inhibition characteristics to the lubricant. Generally,
the concentration of each of these additives, when used, ranges up
to about 20% by weight based on the weight of the lubricating oil
composition, and in one embodiment from about 0.001% to about 20%
by weight, and in one embodiment about 0.01% to about 10% by weight
based on the weight of the lubricating oil composition.
[0055] The ZDDP and hydrocarbon soluble metal compounds may be
added directly to the lubricating oil composition. In one
embodiment, however, they are diluted with a substantially inert,
normally liquid organic diluent such as mineral oil, synthetic oil,
naphtha, alkylated (e.g. C.sub.10 to C.sub.13 alkyl) benzene,
toluene or xylene to form an additive concentrate. These
concentrates usually contain from about 1% to about 100% by weight
and in one embodiment about 10% to about 90% by weight of the
additive mixture.
[0056] In order to illustrate an advantage of the disclosed
embodiments with respect to improving friction characteristics of
lubricating oils, the following non-limiting example is given.
EXAMPLE
[0057] The following example is not intended to limit the
embodiments in any way. Inventive and comparative lubricant
compositions containing the ZDDP compound and metal compound were
tested to provide boundary friction characteristics and thin film
friction characteristics. The friction characteristics of the
compositions were determined using a Mini Traction Machine with a
Spacer Layer Imaging System (MTM-SLIM). The metal compounds were
added to the mixture in the form of a chelate of
2,2,6,6,-tetramethyl-3,5-heptanedionate ligands. The results of
each mixture are given in the following table.
TABLE-US-00003 TABLE 3 ZDDP Metal Total Metal to Compound Compound
Total Metal Phosphorus Boundary Friction (ppm by wt. P) (ppm by
wt.) (ppm by wt.) Ratio at 130.degree. C. ZDDP, 400 ppm P -- 400 1
to 1 0.150 ZDDP, 600 ppm P -- 600 1 to 1 0.178 ZDDP, 400 ppm P 40
ppm Zn 440 1.1 to 1 0.152 ZDDP, 400 ppm P 200 ppm Zn 600 1.5 to 1
0.141 ZDDP, 400 ppm P 400 ppm Zn 800 2 to 1 0.134 ZDDP, 400 ppm P
4000 ppm Zn 4400 11 to 1 0.142 ZDDP, 400 ppm P 200 ppm Ti 600 1.5
to 1 0.133 ZDDP, 400 ppm P 200 ppm Fe 600 1.5 to 1 0.159 ZDDP, 400
ppm P 200 ppm Ca 600 1.5 to 1 0.152 ZDDP, 400 ppm P 200 ppm Zr 600
1.5 to 1 0.152
[0058] The foregoing table 3 illustrates that increasing an amount
of ZDDP compound to provide from 400 ppm total metal to 600 ppm
total metal significantly increase boundary friction from 0.150 at
400 ppm total metal to 0.178 at 600 ppm total metal. However, when
non-phosphorus-containing metal compounds are combined with ZDDP to
provide a total metal content of 600 ppm, the boundary friction is
about the same or lower than with 400 ppm total metal and only ZDDP
in the lubricant composition. Based on the foregoing analysis,
increasing the metal to phosphorus ratio to above about 1.5 to 1 in
a lubricant composition using a non-phosphorus metal compound may
be useful for increasing engine fuel economy.
[0059] In order to further illustrate the advantages of using
certain transition metal compounds in combination with the ZDDP
compound, the thin film friction characteristics of the forgoing
blends were determined and are listed in the following table.
TABLE-US-00004 TABLE 4 ZDDP Metal Total Metal to Compound Compound
Total Metal Phosphorus Thin Film Friction (ppm by wt. P) (ppm by
wt.) (ppm by wt.) Ratio at 100.degree. C. ZDDP, 400 ppm P -- 400 1
to 1 0.042 ZDDP, 600 ppm P -- 600 1 to 1 0.045 ZDDP, 400 ppm P 40
ppm Zn 440 1.1 to 1 0.040 ZDDP, 400 ppm P 200 ppm Zn 600 1.5 to 1
0.043 ZDDP, 400 ppm P 400 ppm Zn 800 2 to 1 0.041 ZDDP, 400 ppm P
4000 ppm Zn 4400 11 to 1 0.024 ZDDP, 400 ppm P 200 ppm Ti 600 1.5
to 1 0.045 ZDDP, 400 ppm P 200 ppm Fe 600 1.5 to 1 0.040 ZDDP, 400
ppm P 200 ppm Ca 600 1.5 to 1 0.056 ZDDP, 400 ppm P 200 ppm Zr 600
1.5 to 1 0.038
[0060] The foregoing table 4 illustrates that not all metals in the
lubricant composition have a beneficial effect on friction
characteristics. In particular, non-transition metals, such as
calcium, may significantly increase the thin film friction of a
lubricant composition compared to the same or greater total metal
content provided by ZDDP and a transition metal compound such as
Zn, Ti, Fe, or Zr.
[0061] At numerous places throughout this specification, reference
has been made to a number of U.S. Patents and publications. All
such cited documents are expressly incorporated in full into this
disclosure as if fully set forth herein.
[0062] The foregoing embodiments are susceptible to considerable
variation in its practice. Accordingly, the embodiments are not
intended to be limited to the specific exemplifications set forth
hereinabove. Rather, the foregoing embodiments are within the
spirit and scope of the appended claims, including the equivalents
thereof available as a matter of law.
[0063] The patentees do not intend to dedicate any disclosed
embodiments to the public, and to the extent any disclosed
modifications or alterations may not literally fall within the
scope of the claims, they are considered to be part hereof under
the doctrine of equivalents.
* * * * *