U.S. patent application number 12/004194 was filed with the patent office on 2009-06-25 for lubricating oil compositions comprising a molybdenum compound and a zinc dialkyldithiophosphate.
Invention is credited to Alexander B. Boffa, Kenji Takeoka.
Application Number | 20090163392 12/004194 |
Document ID | / |
Family ID | 40577937 |
Filed Date | 2009-06-25 |
United States Patent
Application |
20090163392 |
Kind Code |
A1 |
Boffa; Alexander B. ; et
al. |
June 25, 2009 |
Lubricating oil compositions comprising a molybdenum compound and a
zinc dialkyldithiophosphate
Abstract
Provided herein are lubricating oil compositions comprising a
major amount of a base oil, at least one oil-soluble molybdenum
compound and a zinc dialkyldithiophosphate compound, wherein the
molybdenum content derived from the molybdenum compound is at least
10 ppm based on the total weight of the lubricating oil composition
and the phosphorus content derived from the zinc
dialkyldithiophosphate compound is about 200 to 500 ppm based on
the total weight of the lubricating oil composition. The
lubricating oil composition can further comprise at least one
additive. Methods of making and using the lubricating oil
compositions are also described.
Inventors: |
Boffa; Alexander B.;
(Oakland, CA) ; Takeoka; Kenji; (San Rafael,
CA) |
Correspondence
Address: |
JONES DAY
222 EAST 41ST ST
NEW YORK
NY
10017
US
|
Family ID: |
40577937 |
Appl. No.: |
12/004194 |
Filed: |
December 20, 2007 |
Current U.S.
Class: |
508/161 ;
508/165 |
Current CPC
Class: |
C10N 2040/255 20200501;
C10N 2030/54 20200501; C10N 2030/42 20200501; C10M 2219/068
20130101; C10N 2040/253 20200501; C10N 2040/25 20130101; C10M
2223/045 20130101; C10M 2227/066 20130101; C10M 2219/062 20130101;
C10M 141/10 20130101; C10N 2030/06 20130101; C10M 2219/082
20130101; C10M 2219/062 20130101; C10N 2010/12 20130101; C10M
2219/068 20130101; C10N 2010/12 20130101; C10M 2219/082 20130101;
C10N 2010/12 20130101; C10M 2223/045 20130101; C10M 2223/045
20130101; C10M 2223/045 20130101; C10N 2010/12 20130101; C10M
2223/045 20130101; C10N 2010/04 20130101; C10M 2219/062 20130101;
C10N 2010/12 20130101; C10M 2219/068 20130101; C10N 2010/12
20130101; C10M 2219/082 20130101; C10N 2010/12 20130101; C10M
2223/045 20130101; C10N 2010/12 20130101; C10M 2223/045 20130101;
C10N 2010/04 20130101 |
Class at
Publication: |
508/161 ;
508/165 |
International
Class: |
C10M 125/24 20060101
C10M125/24; C10M 125/10 20060101 C10M125/10 |
Claims
1. A lubricating oil composition comprising: i) a major amount of a
base oil, ii) at least one oil-soluble molybdenum compound and iii)
a zinc dialkyldithiophosphate compound, wherein the molybdenum
content derived from the molybdenum compound is at least 10 ppm
Molybdenum based on the total weight of the lubricating oil
composition and the phosphorus content derived from the zinc
dialkyldithiophosphate compound is about 200 ppm to 500 ppm based
on the total weight of the lubricating oil composition.
2. The lubricating oil composition of claim 1, wherein the
oil-soluble molybdenum compound is selected from molybdenum
dithiocarbamate, molybdenum dithiophosphate, molybdenum
dithiophosphinate, molybdenum xanthate, molybdenum thioxanthate,
molybdenum sulfide and a mixture thereof.
3. The lubricating oil composition of claim 1, wherein the
oil-soluble molybdenum compound is selected from molybdenum
dithiocarbamate, molybdenum-succinimide complex and a mixture
thereof.
4. The lubricating oil composition of claim 1, wherein the
molybdenum content derived from the molybdenum compound is from
about 10 to 10,000 ppm molybdenum based on the total weight of the
lubricating oil composition.
5. The lubricating oil composition of claim 1, wherein the
molybdenum content derived from the molybdenum compound is from
about 50 to 1500 ppm molybdenum based on the total weight of the
lubricating oil composition.
6. The lubricating oil composition of claim 1, wherein the
molybdenum content derived from the molybdenum compound is from
about 250 to 1200 ppm molybdenum based on the total weight of the
lubricating oil composition
7. The lubricating oil composition of claim 1, wherein the zinc
dialkyldithiophosphate comprises a straight or branched alkyl group
having 3 to 30 carbon atoms.
8. The lubricating oil composition of claim 1, wherein the zinc
dialkyldithiophosphate comprises an alkyl selected from ethyl,
propyl, butyl, pentyl, methylpentyl, hexyl, heptyl, octyl, nonyl,
decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,
hexadecyl, heptadecyl, and octadecyl.
9. The lubricating oil composition of claim 1, wherein the
phosphorus content derived from the zinc dialkyldithiophosphate
compound is about 200, 250, 300, 350, 400, 450 or 500 ppm based on
the total weight of the lubricating oil composition.
10. The lubricating oil composition of claim 1, wherein the
phosphorus content derived from the zinc dialkyldithiophosphate
compound is about 250 ppm based on the total weight of the
lubricating oil composition.
11. The lubricating oil composition of claim 1 further comprising
at least one additive selected from the group consisting of
antioxidants, antiwear agents, detergents, rust inhibitors,
demulsifiers, friction modifiers, multi-functional additives,
viscosity index improvers, pour point depressants, foam inhibitors,
metal deactivators, dispersants, corrosion inhibitors, lubricity
improvers and combinations thereof.
12. A method of making a lubricating oil composition comprising the
step of mixing: i) a major amount of a base oil, ii) at least one
oil-soluble molybdenum compound and iii) a zinc
dialkyldithiophosphate compound, wherein the molybdenum content
derived from the molybdenum compound is at least 10 ppm based on
the total weight of the lubricating oil composition and the
phosphorus content derived from the zinc dialkyldithiophosphate
compound is about 200 to 500 ppm based on the total weight of the
lubricating oil composition.
13. A method of lubricating a motor engine comprising the step of
operating the engine with the lubricating oil composition of claim
1.
14. The method of claim 15, wherein the molybdenum content derived
from the molybdenum compound is from 10 to 10,000 ppm based on the
total weight of the lubricating oil composition.
15. The method of claim 15, wherein the phosphorus content derived
from the zinc dialkyldithiophosphate compound is about 200, 250,
300, 350, 400, 450 or 500 ppm based on the total weight of the
lubricating oil composition.
16. The method of claim 15, wherein the phosphorus content derived
from the zinc dialkyldithiophosphate compound is about 250 ppm
based on the total weight of the lubricating oil composition.
Description
FIELD
[0001] Provided herein are lubricating oil compositions comprising
a base oil, an oil soluble molybdenum compound and a zinc
dithiophosphate compound. Methods of making and using the
lubricating oil compositions are also described.
BACKGROUND
[0002] Lubricating oil compositions used to lubricate internal
combustion engines contain base oil of lubricating viscosity, or a
mixture of such oils, and additives used to improve the performance
characteristics of the oil. For example, additives are used to
improve detergency, to reduce engine wear, to provide stability
against heat and oxidation, to reduce oil consumption, to inhibit
corrosion, to act as a dispersant, and to reduce friction loss.
Some additives provide multiple benefits, such as
dispersant-viscosity modifiers. Other additives, while improving
one characteristic of the lubricating oil, have an adverse effect
on other characteristics. Thus, to provide lubricating oil having
optimal overall performance, it is necessary to characterize and
understand all the effects of the various additives available, and
carefully balance the additive content of the lubricant.
[0003] It has been proposed in many patents and articles (for
example, U.S. Pat. Nos. 4,164,473; 4,176,073; 4,176,074; 4,192,757;
4,248,720; 4,201,683; 4,289,635; and 4,479,883) that oil-soluble
molybdenum compounds are useful as lubricant additives. In
particular, the addition of molybdenum compounds to oil,
particularly molybdenum dithiocarbamate compounds, provides the oil
with improved boundary friction characteristics and bench tests
demonstrate that the coefficient of friction of oil containing such
molybdenum compounds is generally lower than that of oil containing
organic friction modifiers. This reduction in coefficient of
friction results in improved antiwear properties and may contribute
to enhanced fuel economy in gasoline or diesel fired engines,
including both short- and long-term fuel economy properties (i.e.,
fuel economy retention properties). To provide antiwear effects,
molybdenum compounds are generally added in amounts introducing
from about 350 ppm up to 2,000 ppm of molybdenum into the oil.
molybdenum compounds are effective antiwear agents and may further
provide fuel economy benefits, such molybdenum compounds are
expensive relative to more conventional, metal-free (ashless)
organic friction modifiers
[0004] Therefore, it is desirable to find a lubricating oil
composition that provides improved fuel economy benefit;
demonstrates excellent wear protection characteristics, is
relatively low in cost.
SUMMARY
[0005] Provided herein are lubricating oil compositions that
provide an improved friction reduction. The lubricating oil
compositions comprising
[0006] i) a major amount of a base oil,
[0007] ii) at least one oil-soluble molybdenum compound and
[0008] iii) a zinc dialkyldithiophosphate compound,
wherein the molybdenum content derived from the molybdenum compound
is at least about 10 ppm based on the total weight of the
lubricating oil composition and the phosphorus content derived from
the zinc dialkyldithiophosphate compound is about 200 to 500 ppm
based on the total weight of the lubricating oil composition.
[0009] In certain aspects, the base oil is present in an amount
greater than about 40%, 50%, 60% or about 70% by weight of the
lubricating oil compositions.
[0010] In certain embodiments, the lubricating oil composition
disclosed herein further comprises at least one additive selected
from the group consisting of antioxidants, antiwear agents,
detergents, rust inhibitors, demulsifiers, friction modifiers,
multi-functional additives, viscosity index improvers, pour point
depressants, foam inhibitors, metal deactivators, dispersants,
corrosion inhibitors, lubricity improvers, thermal stability
improvers, anti-haze additives, dyes, markers, and combinations
thereof.
[0011] Also provided herein are methods of making lubricating oil
compositions. In one aspect, the methods comprise the step of
mixing
[0012] i) a major amount of a base oil,
[0013] ii) at least one oil-soluble molybdenum compound and
[0014] iii) a zinc dialkyldithiophosphate compound,
wherein the molybdenum content derived from the molybdenum compound
is at least about 10 ppm based on the total weight of the
lubricating oil composition and the phosphorus content derived from
the zinc dialkyldithiophosphate compound is about 200 to 500 ppm
based on the total weight of the lubricating oil composition. In
certain embodiments, the molybdenum compound and the zinc
dialkyldithiophosphate compound used as described herein show
synergy and resulting low friction coefficient in prototype GF-5
lubricating compositions.
[0015] Also provided herein are methods of lubricating a motor
engine with a lubricating oil compositions provided herein. In one
aspect, the methods comprise the step of operating the engine with
the lubricating oil composition of provided herein.
[0016] Other embodiments will be in part apparent and in part
pointed out hereinafter.
DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 depicts a plot of friction by High Frequency
Reciprocating Rig test (HFRR) versus phosphorus content of the
lubricant oil compositions described herein.
DEFINITIONS
[0018] To facilitate the understanding of the subject matter
disclosed herein, a number of terms, abbreviations or other
shorthand as used herein are defined below. Any term, abbreviation
or shorthand not defined is understood to have the ordinary meaning
used by a skilled artisan contemporaneous with the submission of
this application.
[0019] "A major amount" of a base oil refers to the amount of the
base oil is at least 40 wt. % of the lubricating oil composition.
In some embodiments, "a major amount" of a base oil refers to an
amount of the base oil more than 50 wt. %, more than 60 wt. %, more
than 70 wt. %, more than 80 wt. %, or more than 90 wt. % of the
lubricating oil composition.
[0020] "Sulfated ash content" refers to the amount of
metal-containing additives (e.g., calcium, magnesium, molybdenum,
zinc, etc.) in a lubricating oil and is typically measured
according to ASTM D874, which is incorporated herein by
reference.
[0021] A composition that is "substantially free" of a compound
refers to a composition which contains less than 20 wt. %, less
than 10 wt. %, less than 5 wt. %, less than 4 wt. %, less than 3
wt. %, less than 2 wt. %, less than 1 wt. %, less than 0.5 wt. %,
less than 0.1 wt. %, or less than 0.01 wt. % of the compound, based
on the total weight of the composition.
[0022] A composition that is "free" of a compound refers to a
composition which contains from 0.001 wt. % to 0 wt. % of the
compound, based on the total weight of the composition.
[0023] In the following description, all numbers disclosed herein
are approximate values, regardless whether the word "about" or
"approximate" is used in connection therewith. They may vary by 1
percent, 2 percent, 5 percent, or, sometimes, 10 to 20 percent.
Whenever a numerical range with a lower limit, R.sup.L, and an
upper limit, R.sup.U, is disclosed, any number falling within the
range is specifically disclosed. In particular, the following
numbers within the range are specifically disclosed:
R=R.sup.L+k*(R.sup.U-R.sup.L), wherein k is a variable ranging from
1 percent to 100 percent with a 1 percent increment, i.e., k is 1
percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50
percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97
percent, 98 percent, 99 percent, or 100 percent. Moreover, any
numerical range defined by two R numbers as defined in the above is
also specifically disclosed.
DESCRIPTION OF EMBODIMENTS
[0024] Provided herein are lubricating oil compositions
comprising:
[0025] i) a major amount of a base oil,
[0026] ii) at least one oil-soluble molybdenum compound and
[0027] iii) a zinc dialkyldithiophosphate compound,
wherein the molybdenum content derived from the molybdenum compound
is at least about 10 ppm based on the total weight of the
lubricating oil composition and the phosphorus content derived from
the zinc dialkyldithiophosphate compound is 200 to 500 ppm based on
the total weight of the lubricating oil composition.
[0028] In certain embodiments, the phosphorus content of the
composition is about 200 to 500 ppm. In other embodiments, the
phosphorus content of the composition is about 250 to 400 ppm,
about 300 to 400 ppm. In certain embodiments, the SAE viscosity of
the composition is 5W-20.
[0029] i). The Base Oil of Lubricating Viscosity
[0030] The lubricating oil compositions disclosed herein generally
comprise at least one oil of lubricating viscosity. Any base oil
known to a skilled artisan can be used as the oil of lubricating
viscosity disclosed herein. Some base oils suitable for preparing
the lubricating oil compositions have been described in Mortier et
al., "Chemistry and Technology of Lubricants," 2nd Edition, London,
Springer, Chapters 1 and 2 (1996); and A. Sequeria, Jr., "Lubricant
Base Oil and Wax Processing," New York, Marcel Decker, Chapter 6,
(1994); and D. V. Brock, Lubrication Engineering, Vol. 43, pages
184-5, (1987), all of which are incorporated herein by reference.
Generally, the amount of the base oil in the lubricating oil
composition may be from about 50 to about 99.5 wt. %, based on the
total weight of the lubricating oil composition. In some
embodiments, the amount of the base oil in the lubricating oil
composition is from about 75 to about 99 wt. %, from about 80 to
about 98.5 wt. %, or from about 80 to about 98 wt. %, based on the
total weight of the lubricating oil composition. In certain
embodiments, the amount of base oil in the lubricant oil
compositions provided herein is about 45%, 50%, 52%, 54%, 56%, 58%,
60%, 62%, 64%, 66%, 68%, 70%, 75%, 80%, 85% or about 90% by total
weight of the composition.
[0031] In certain embodiments, the base oil is or comprises any
natural or synthetic lubricating base oil fraction. Some
non-limiting examples of synthetic oils include oils, such as
polyalphaolefins or PAOs, prepared from the polymerization of at
least one alpha-olefin, such as ethylene, or from hydrocarbon
synthesis procedures using carbon monoxide and hydrogen gases, such
as the Fisher-Tropsch process. In certain embodiments, the base oil
comprises less than about 10 wt. % of one or more heavy fractions,
based on the total weight of the base oil. A heavy fraction refers
to a lube oil fraction having a viscosity of at least about 20 cSt
at 100.degree. C. In certain embodiments, the heavy fraction has a
viscosity of at least about 25 cSt or at least about 30 cSt at
100.degree. C. In further embodiments, the amount of the one or
more heavy fractions in the base oil is less than about 10 wt. %,
less than about 5 wt. %, less than about 2.5 wt. %, less than about
1 wt. %, or less than about 0.1 wt. %, based on the total weight of
the base oil. In still further embodiments, the base oil comprises
no heavy fraction.
[0032] In certain embodiments, the lubricating oil compositions
comprise a major amount of a base oil of lubricating viscosity. In
some embodiments, the base oil has a kinematic viscosity at
100.degree. C. from about 2 centistokes (cSt) to about 20 cSt, from
about 4 centistokes (cSt) to about 16 cSt, or from about 5 cSt to
about 13 cSt. The kinematic viscosity of the base oils or the
lubricating oil compositions disclosed herein can be measured
according to ASTM D 445, which is incorporated herein by
reference.
[0033] In other embodiments, the base oil is or comprises a base
stock or blend of base stocks. In further embodiments, the base
stocks are manufactured using a variety of different processes
including, but not limited to, distillation, solvent refining,
hydrogen processing, oligomerization, esterification, and
rerefining. In some embodiments, the base stocks comprise a
rerefined stock. In further embodiments, the rerefined stock shall
be substantially free from materials introduced through
manufacturing, contamination, or previous use.
[0034] In some embodiments, the base oil comprises one or more of
the base stocks in one or more of Groups I-V as specified in the
American Petroleum Institute (API) Publication 1509, Fourteen
Edition, December 1996 (i.e., API Base Oil Interchangeability
Guidelines for Passenger Car Motor Oils and Diesel Engine Oils),
which is incorporated herein by reference. The API guideline
defines a base stock as a lubricant component that may be
manufactured using a variety of different processes. Groups I, II
and III base stocks are mineral oils, each with specific ranges of
the amount of saturates, sulfur content and viscosity index. Group
IV base stocks are polyalphaolefins (PAO). Group V base stocks
include all other base stocks not included in Group I, II, III, or
IV.
[0035] The saturates levels, sulfur levels and viscosity indices
for Group I, II, III, IV and V base stocks are listed in Table 1
below.
TABLE-US-00001 TABLE 1 Sulfur (As Viscosity Index (As determined
Saturates (As determined determined by by ASTM D 4294, ASTM D Group
by ASTM D 2007) ASTM D 2270) 4297 or ASTM D 3120) I Less than 90%
saturates. Greater than or Greater than or equal to 80 and equal to
0.03% less than 120. sulfur. II Greater than or equal to Less than
or equal Greater than or equal to 80 and 90% saturates. to 0.03%
sulfur. less than 120. III Greater than or equal to Less than or
equal Greater than or equal to 120. 90% saturates. to 0.03% sulfur.
IV Defined as polyalphaolefins (PAO) V All other base stocks not
included in Groups I, II, III or IV
[0036] In some embodiments, the base oil comprises one or more of
the base stocks in Group I, II, III, IV, V or a combination
thereof. In other embodiments, the base oil comprises one or more
of the base stocks in Group II, III, IV or a combination thereof.
In further embodiments, the base oil comprises one or more of the
base stocks in Group II, III, IV or a combination thereof wherein
the base oil has a kinematic viscosity from about 2.5 centistokes
(cSt) to about 20 cSt, from about 4 cSt to about 20 cSt, or from
about 5 cSt to about 16 cSt at 100.degree. C.
[0037] The base oil may be selected from the group consisting of
natural oils of lubricating viscosity, synthetic oils of
lubricating viscosity and mixtures thereof. In some embodiments,
the base oil includes base stocks obtained by isomerization of
synthetic wax and slack wax, as well as hydrocrackate base stocks
produced by hydrocracking (rather than solvent extracting) the
aromatic and polar components of the crude. In other embodiments,
the base oil of lubricating viscosity includes natural oils, such
as animal oils, vegetable oils, mineral oils (e.g., liquid
petroleum oils and solvent treated or acid-treated mineral oils of
the paraffinic, naphthenic or mixed paraffinic-naphthenic types),
oils derived from coal or shale, and combinations thereof. Some
non-limiting examples of animal oils include bone oil, lanolin,
fish oil, lard oil, dolphin oil, seal oil, shark oil, tallow oil,
and whale oil. Some non-limiting examples of vegetable oils include
castor oil, olive oil, peanut oil, rapeseed oil, corn oil, sesame
oil, cottonseed oil, soybean oil, sunflower oil, safflower oil,
hemp oil, linseed oil, tung oil, oiticica oil, jojoba oil, and
meadow foam oil. Such oils may be partially or fully
hydrogenated.
[0038] In some embodiments, the synthetic oils of lubricating
viscosity include hydrocarbon oils and halo-substituted hydrocarbon
oils such as polymerized and inter-polymerized olefins,
alkylbenzenes, polyphenyls, alkylated diphenyl ethers, alkylated
diphenyl sulfides, as well as their derivatives, analogues and
homologues thereof, and the like. In other embodiments, the
synthetic oils include alkylene oxide polymers, interpolymers,
copolymers and derivatives thereof wherein the terminal hydroxyl
groups can be modified by esterification, etherification, and the
like. In further embodiments, the synthetic oils include the esters
of dicarboxylic acids with a variety of alcohols. In certain
embodiments, the synthetic oils include esters made from C.sub.5 to
C.sub.12 monocarboxylic acids and polyols and polyol ethers. In
further embodiments, the synthetic oils include tri-alkyl phosphate
ester oils, such as tri-n-butyl phosphate and tri-iso-butyl
phosphate.
[0039] In some embodiments, the synthetic oils of lubricating
viscosity include silicon-based oils (such as the polyakyl-,
polyaryl-, polyalkoxy-, polyaryloxy-siloxane oils and silicate
oils). In other embodiments, the synthetic oils include liquid
esters of phosphorus-containing acids, polymeric tetrahydrofurans,
polyalphaolefins, and the like.
[0040] Base oil derived from the hydroisomerization of wax may also
be used, either alone or in combination with the aforesaid natural
and/or synthetic base oil. Such wax isomerate oil is produced by
the hydroisomerization of natural or synthetic waxes or mixtures
thereof over a hydroisomerization catalyst.
[0041] In further embodiments, the base oil comprises a
poly-alpha-olefin (PAO). In general, the poly-alpha-olefins may be
derived from an alpha-olefin having from about 2 to about 30, from
about 4 to about 20, or from about 6 to about 16 carbon atoms.
Non-limiting examples of suitable poly-alpha-olefins include those
derived from octene, decene, mixtures thereof, and the like. These
poly-alpha-olefins may have a viscosity from about 2 to about 15,
from about 3 to about 12, or from about 4 to about 8 centistokes at
100.degree. C. In some instances, the poly-alpha-olefins may be
used together with other base oils such as mineral oils.
[0042] In further embodiments, the base oil comprises a
polyalkylene glycol or a polyalkylene glycol derivative, where the
terminal hydroxyl groups of the polyalkylene glycol may be modified
by esterification, etherification, acetylation and the like.
Non-limiting examples of suitable polyalkylene glycols include
polyethylene glycol, polypropylene glycol, polyisopropylene glycol,
and combinations thereof. Non-limiting examples of suitable
polyalkylene glycol derivatives include ethers of polyalkylene
glycols (e.g., methyl ether of polyisopropylene glycol, diphenyl
ether of polyethylene glycol, diethyl ether of polypropylene
glycol, etc.), mono- and polycarboxylic esters of polyalkylene
glycols, and combinations thereof. In some instances, the
polyalkylene glycol or polyalkylene glycol derivative may be used
together with other base oils such as poly-alpha-olefins and
mineral oils.
[0043] In further embodiments, the base oil comprises any of the
esters of dicarboxylic acids (e.g., phthalic acid, succinic acid,
alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic
acid, suberic acid, sebacic acid, fumiaric acid, adipic acid,
linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl
malonic acids, and the like) with a variety of alcohols (e.g.,
butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl
alcohol, ethylene glycol, diethylene glycol monoether, propylene
glycol, and the like). Non-limiting examples of these esters
include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl
fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate,
dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the
2-ethylhexyl diester of linoleic acid dimer, and the like.
[0044] In further embodiments, the base oil comprises a hydrocarbon
prepared by the Fischer-Tropsch process. The Fischer-Tropsch
process prepares hydrocarbons from gases containing hydrogen and
carbon monoxide using a Fischer-Tropsch catalyst. These
hydrocarbons may require further processing in order to be useful
as base oils. For example, the hydrocarbons may be dewaxed,
hydroisomerized, and/or hydrocracked using processes known to a
person of ordinary skill in the art.
[0045] In further embodiments, the base oil comprises an unrefined
oil, a refined oil, a rerefined oil, or a mixture thereof.
Unrefined oils are those obtained directly from a natural or
synthetic source without further purification treatment.
Non-limiting examples of unrefined oils include shale oils obtained
directly from retorting operations, petroleum oils obtained
directly from primary distillation, and ester oils obtained
directly from an esterification process and used without further
treatment. Refined oils are similar to the unrefined oils except
the former have been further treated by one or more purification
processes to improve one or more properties. Many such purification
processes are known to those skilled in the art such as solvent
extraction, secondary distillation, acid or base extraction,
filtration, percolation, and the like. Rerefined oils are obtained
by applying to refined oils processes similar to those used to
obtain refined oils. Such rerefined oils are also known as
reclaimed or reprocessed oils and often are additionally treated by
processes directed to removal of spent additives and oil breakdown
products.
[0046] ii). Oil Soluble Molybdenum Compounds
[0047] For the lubricating oil compositions provided herein, any
suitable oil-soluble molybdenum compound can be employed. Exemplary
of such oil-soluble molybdenum compounds include, but are not
limited to dithiocarbamates, dithiophosphates, dithiophosphinates,
xanthates, thioxanthates, sulfides, and the like, and mixtures
thereof. In certain embodiments, the molybdenum compounds are
molybdenum dithiocarbamates, dialkyldithiophosphates, alkyl
xanthates and alkylthioxanthates.
[0048] The molybdenum compound may be mono-, di-, tri- or
tetra-nuclear. In certain embodiments, the compound is a dinuclear
or trinuclear molybdenum compound. In one embodiment, the
molybdenum compound is an organo-molybdenum compound. In another
embodiment, the molybdenum compound is selected from the group
consisting of molybdenum dithiocarbamates (MoDTC), molybdenum
dithiophosphates, molybdenum dithiophosphinates, molybdenum
xanthates, molybdenum thioxanthates, molybdenum sulfides and
mixtures thereof. In another embodiment, the molybdenum compound is
present as a molybdenum dithiocarbamate or a trinuclear
organo-molybdenum compound. In one embodiment, the oil-soluble
molybdenum compound is selected from molybdenum dithiocarbamate,
molybdenum-succinimide complex and a mixture thereof.
[0049] In certain aspects, the molybdenum compound may be an acidic
molybdenum compound. These compounds will react with a basic
nitrogen compound as measured by ASTM test D-664 or D-2896
titration procedure and are typically hexavalent. Examples of such
compounds include molybdic acid, ammonium molybdate, sodium
molybdate, potassium molybdate, and other alkaline metal molybdates
and other molybdenum salts, e.g., hydrogen sodium molybdate,
MoOCl.sub.4, MoO.sub.2Br.sub.2, Mo.sub.2O.sub.3Cl.sub.6, molybdenum
trioxide or similar acidic molybdenum compounds. Alternatively, the
compositions herein comprise molybdenum/sulfur complexes of basic
nitrogen compounds as described, for example, in U.S. Pat. Nos.
4,263,152; 4,285,822; 4,283,295; 4,272,387; 4,265,773; 4,261,843;
4,259,195; 4,259,194 and 6,562,765; and WO 94/06897.
[0050] The basic nitrogen compound used to prepare the
oxymolybdenum compounds for use herein have at least one basic
nitrogen and are, in certain embodiments, oil-soluble. Typical
examples of such compositions are succinimides, carboxylic acid
amides, hydrocarbyl monoamines, hydrocarbon polyamines, Mannich
bases, phosphoramides, thiophosphoramides, phosphonamides,
dispersant viscosity index improvers, and mixtures thereof. Any of
the nitrogen-containing compositions may be after-treated with,
e.g., boron, using procedures well known in the art so long as the
compositions continue to contain basic nitrogen. These
after-treatments are particularly applicable to succinimides and
Mannich base compositions.
[0051] The mono and polysuccinimides that can be used to prepare
the molybdenum complexes described herein are disclosed in numerous
references and are well known in the art. Certain exemplary
succinimides and the related materials are described in U.S. Pat.
Nos. 3,219,666; 3,172,892; and 3,272,746, the disclosures of which
are hereby incorporated by reference. The term "succinimide" is
understood in the art to include many of the amide, imide, and
amidine species which may also be formed. The predominant product
however is a succinimide and this term has been generally accepted
as meaning the product of a reaction of an alkenyl substituted
succinic acid or anhydride with a nitrogen-containing compound. In
certain embodiments, succinimides for use herein are commercial
available succinimides, such as those prepared from a hydrocarbyl
succinic anhydride, wherein the hydrocarbyl group contains from
about 24 to about 350 carbon atoms, and an ethylene amine, said
ethylene amines being characterized by ethylene diamine, diethylene
triamine, triethylene tetramine, and tetraethylene pentamine. In
one embodiment, the succinimides include succinimides prepared from
polyisobutenyl succinic anhydride of 70 to 128 carbon atoms and
tetraethylene pentamine or triethylene tetramine or mixtures
thereof.
[0052] Also included in the succinimides are the cooligomers of a
hydrocarbyl succinic acid or anhydride and a poly secondary amine
containing at least one tertiary amino nitrogen in addition to two
or more secondary amino groups. In certain embodiments, the
cooligomers have an average molecular weight between 1,500 and
50,000. In one embodiment, the molybdenum compound for use in the
compositions herein is prepared by reacting polyisobutenyl succinic
anhydride and ethylene dipiperazine.
[0053] In certain embodiment, carboxylic acid amide compositions
are also suitable starting materials for preparing the
oxymolybdenum compounds used herein. Typical of such compounds are
those disclosed in U.S. Pat. No. 3,405,064, the disclosure of which
is hereby incorporated by reference. These compositions can be
prepared by reacting a carboxylic acid or anhydride or ester
thereof, having at least 12 to about 350 aliphatic carbon atoms in
the principal aliphatic chain and, if desired, having sufficient
pendant aliphatic groups to render the molecule oil soluble with an
amine or a hydrocarbyl polyamine, such as an ethylene amine, to
give a mono or polycarboxylic acid amide. In one embodiment, the
amides are prepared from (1) a carboxylic acid of the formula
R'COOH, where R' is C.sub.12-20 alkyl or a mixture of this acid
with a polyisobutenyl carboxylic acid in which the polyisobutenyl
group contains from 72 to 128 carbon atoms and (2) an ethylene
amine, especially triethylene tetramine or tetraethylene pentamine
or mixtures thereof.
[0054] Another class of compounds which can be used to prepare
molybdenum compounds are hydrocarbyl monoamines and hydrocarbyl
polyamines, such as those disclosed in U.S. Pat. No. 3,574,576, the
disclosure of which is hereby incorporated by reference. The
hydrocarbyl group, for example alkyl, or olefinic having one or two
sites of unsaturation, usually contains from 9 to 350, preferably
from 20 to 200 carbon atoms. Exemplary of such hydrocarbyl
polyamines are those which are derived, e.g., by reacting
polyisobutenyl chloride and a polyalkylene polyamine, such as an
ethylene amine, e.g., ethylene diamine, diethylene triamine,
tetraethylene pentamine, 2-aminoethylpiperazine, 1,3-propylene
diamine, 1,2-propylenediamine, and the like.
[0055] Another class of compounds useful for supplying basic
nitrogen are the Mannich base compositions. These compositions are
prepared from a phenol or C.sub.9-200 alkylphenol, an aldehyde,
such as formaldehyde or formaldehyde precursor such as
paraformaldehyde, and an amine compound. The amine may be a mono or
polyamine and typical compositions are prepared from an alkylamine,
such as methylamine or an ethylene amine, such as, diethylene
triamine, or tetraethylene pentamine, and the like. The phenolic
material may be sulfurized and preferably is dodecylphenol or a
C.sub.80-100 alkylphenol. Typical Mannich bases which can be used
are disclosed in U.S. Pat. Nos. 4,157,309 and 3,649,229; 3,368,972;
and 3,539,663, the disclosures of which are hereby incorporated by
reference.
[0056] Another class of composition useful for preparing the
oxymolybdenum complexes employed in the lubricating oil
compositions provided herein are the phosphoramides and
phosphonamides such as those disclosed in U.S. Pat. Nos. 3,909,430
and 3,968,157, the disclosures of which are hereby incorporated by
reference. These compositions may be prepared by forming a
phosphorus compound having at least one P--N bond. They can be
prepared, for example, by reacting phosphorus oxychloride with a
hydrocarbyl diol in the presence of a monoamine or by reacting
phosphorus oxychloride with a difunctional secondary amine and a
mono-functional amine. Thiophosphoramides can be prepared by
reacting an unsaturated hydrocarbon compound containing from 2 to
450 or more carbon atoms, such as polyethylene, polyisobutylene,
polypropylene, ethylene, 1-hexene, 1,3-hexadiene, isobutylene,
4-methyl-1-pentene, and the like, with phosphorus pentasulfide and
a nitrogen-containing compound as defined above, particularly an
alkylamine, alkyldiamine, alkylpolyamine, or an alkyleneamine, such
as ethylene diamine, diethylenetriamine, triethylenetetramine,
tetraethylenepentamine, and the like.
[0057] Further molybdenum compounds useful in the compositions
provided herein are organo-molybdenum compounds of the formulae
Mo(ROCS.sub.2).sub.4 and
Mo(RSCS.sub.2).sub.4
[0058] wherein R is an organic group selected from the group
consisting of alkyl, aryl, aralkyl and alkoxyalkyl, generally of
from 1 to 30 carbon atoms, and in one embodiment, from 2 to 12
carbon atoms and in another embodiment, alkyl of 2 to 12 carbon
atoms.
[0059] In one embodiment, the molybdenum compounds are
dithiocarbamates of molybdenum represented by the formula:
##STR00001##
[0060] wherein, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each
independently a straight-chain or branched-chain alkyl group or a
straight-chain or branched-chain alkenyl group having four to
eighteen carbons; and X.sub.1, X.sub.2, X.sub.3 and X.sub.4 are
each independently an oxygen atom or a sulfur atom, the ratio
between the number of the oxygen atom or atoms and that of the
sulfur atom or atoms with respect to X.sub.1 through X.sub.4 being
1/3 to 3/1. In one embodiment, R.sub.1, R.sub.2, R.sub.3 and
R.sub.4, are each alkyl. In one embodiment, the alkyl is butyl,
2-ethylhexyl, isotridecyl or stearyl. The R.sub.1, R.sub.2, R.sub.3
and R.sub.4 groups in one molybdenum dithiocarbamate may be
identical with or different from each other. Further, two or more
molybdenum dithiocarbamates having different R.sub.1, R.sub.2,
R.sub.3 and R.sub.4 groups may be used in a mixed state.
[0061] In one embodiment, organo-molybdenum compounds useful in the
lubricating compositions herein are trinuclear molybdenum
compounds, including those of the formula
Mo.sub.3S.sub.kL.sub.nQ.sub.z and mixtures thereof, wherein L are
independently selected ligands having organic groups with a
sufficient number of carbon atoms to render the compound soluble or
dispersible in the oil, n is from 1 to 4, k varies from 4 through
7, Q is selected from the group of neutral electron donating
compounds such as water, amines, alcohols, phosphines, and ethers,
and z ranges from 0 to 5 and includes non-stoichiometric values. In
certain embodiments, at least 21 total carbon atoms are present
among all the ligands' organic groups, such as at least 25, at
least 30, or at least 35 carbon atoms.
[0062] The ligands are independently selected from the group
of:
##STR00002##
[0063] and mixtures thereof, wherein X, X.sub.1, X.sub.2, and Y are
independently selected from the group of oxygen and sulfur, and
wherein R.sub.1, R.sub.2, and R are each independently selected
from hydrogen and organic groups that may be the same or different.
In one embodiment, the organic groups are hydrocarbyl groups such
as alkyl (e.g., in which the carbon atom attached to the remainder
of the ligand is primary or secondary), aryl, substituted aryl and
ether groups. In one embodiment, each ligand has the same
hydrocarbyl group.
[0064] The term "hydrocarbyl" denotes a substituent having carbon
atoms directly attached to the remainder of the ligand and is
predominantly hydrocarbyl in character, exemplary substituents
include the following:
[0065] 1. Hydrocarbon substituents, that is, aliphatic (for example
alkyl or alkenyl), alicyclic (for example cycloalkyl or
cycloalkenyl) substituents, aromatic-, aliphatic- and
alicyclic-substituted aromatic nuclei and the like, as well as
cyclic substituents wherein the ring is completed through another
portion of the ligand (that is, any two indicated substituents may
together form an alicyclic group).
[0066] 2. Substituted hydrocarbon substituents, that is, those
containing non-hydrocarbon groups which do not alter the
predominantly hydrocarbyl character of the substituent. Those
skilled in the art are aware of suitable groups (e.g., halo,
especially chloro and fluoro, amino, alkoxyl, mercapto,
alkylmercapto, nitro, nitroso, sulfoxy, and the like).
[0067] 3. Hetero substituents, that is, substituents which, while
predominantly hydrocarbon in character, contain atoms other than
carbon present in a chain or ring otherwise composed of carbon
atoms.
[0068] In certain embodiments, the organic groups of the ligands
have a sufficient number of carbon atoms to render the compound
soluble or dispersible in the oil. For example, the number of
carbon atoms in each group will generally range between about 1 to
about 100, from about 1 to about 30 or between about 4 to about 20.
In certain embodiments, the ligands include dialkyldithiophosphate,
alkylxanthate, and dialkyldithiocarbamate. In one embodiment, the
ligand is dialkyldithiocarbamate. Organic ligands containing two or
more of the above flnctionalities can also serve as ligands by
binding to one or more of the cores. Those skilled in the art will
realize that formation of the compounds provided herein requires
selection of ligands having the appropriate charge to balance the
core's charge.
[0069] Compounds having the formula Mo.sub.3S.sub.kL.sub.nQ.sub.z
to have cationic cores surrounded by anionic ligands and are
represented by structures such as
##STR00003##
[0070] and have net charges of +4. Consequently, in order to
solubilize these cores the total charge among all the ligands must
be -4. In one embodiment, four monoanionic ligands are present.
Without wishing to be bound by any theory, it is believed that two
or more trinuclear cores may be bound or interconnected by means of
one or more ligands and the ligands may be multidentate. This
includes the case of a multidentate ligand having multiple
connections to a single core. It is believed that oxygen and/or
selenium may be substituted for sulfur in the core(s).
[0071] Oil-soluble or dispersible trinuclear molybdenum compounds
can be prepared by reacting in the appropriate liquid(s)/solvent(s)
a molybdenum source such as
(NH.sub.4).sub.2Mo.sub.3S.sub.13.n(H.sub.2O), where n varies
between 0 and 2 and includes non-stoichiometric values, with a
suitable ligand source such as a tetralkylthiuram disulfide. Other
oil-soluble or dispersible trinuclear molybdenum compounds can be
formed during a reaction in the appropriate solvent(s) of a
molybdenum source such as of
(NH.sub.4).sub.2Mo.sub.3S.sub.13.n(H.sub.2O), a ligand source such
as tetralkylthiuram disulfide, dialkyldithiocarbamate, or
dialkyldithiophosphate, and a sulfur abstracting agent such as
cyanide ions, sulfite ions, or substituted phosphines.
Alternatively, a trinuclear molybdenum-sulfur halide salt such as
[M']2 [Mo.sub.3S.sub.7A6], where M' is a counter ion, and A is a
halogen such as Cl, Br, or I, may be reacted with a ligand source
such as a dialkyldithiocarbamate or dialkyldithiophosphate in the
appropriate liquid(s)/solvent(s) to form an oil-soluble or
dispersible trinuclear molybdenum compound. The appropriate
liquid/solvent may be, for example, aqueous or organic.
[0072] A compound's oil solubility or dispersibility may be
influenced by the number of carbon atoms in the ligand's organic
groups. In the compounds herein, at least 21 total carbon atoms
should be present among all the ligands' organic groups. In certain
embodiments, the ligand source chosen has a sufficient number of
carbon atoms in its organic groups to render the compound soluble
or dispersible in the lubricating composition.
[0073] The terms "oil-soluble" or "dispersible" used herein do not
necessarily indicate that the compounds or additives are soluble,
dissolvable, miscible, or capable of being suspended in the oil in
all proportions. These do mean, however, that they are, for
instance, soluble or stably dispersible in oil to an extent
sufficient to exert their intended effect in the environment in
which the oil is employed. Moreover, the additional incorporation
of other additives may also permit incorporation of higher levels
of a particular additive, if desired.
[0074] The lubricating compositions provided herein contain the
molybdenum compound at a concentration of at least about 10 ppm in
terms of molybdenum content. In certain embodiments, the molybdenum
compound is at a concentration from about 10 ppm to about 10,000
ppm in terms of molybdenum content. In certain embodiments, the
molybdenum compound at a concentration from about 50 to 1500 ppm,
or about 250 to 1200 ppm in terms of molybdenum content. In one
embodiment, the molybdenum compound is at a concentration of about
10 ppm, 50 ppm, 100 ppm, 250 ppm, 500 ppm, 750 ppm, or 1000 ppm in
terms of molybdenum content.
[0075] The amount of molybdenum may be determined by Inductively
Coupled Plasma (ICP) emission spectroscopy using the method
described in ASTM D5185.
[0076] iii). Zinc Dialkyldithiophosphate Compounds
[0077] The lubricating oil compositions provided herein
additionally contain a zinc dialkyldithiophosphate compound. The
alkyl group in the zinc dialkyldithiophosphate compound is, for
example, branched or non-branched alkyl containing 3 to 30 carbon
atoms. In another embodiment, the alkyl group has 3 to 8 carbon
atoms. Examples of alkyl groups include a straight or branched
ethyl, propyl, butyl, pentyl, methylpentyl, hexyl, heptyl, octyl,
nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,
hexadecyl, heptadecyl, and octadecyl groups.
[0078] These zinc dialkyldithiophosphate salts can be prepared in
accordance with known techniques by first forming a dihydrocarbyl
dithiophosphoric acid (DDPA), usually by reaction of one or more
alcohol or a phenol with P.sub.2S.sub.5 and then neutralizing the
formed DDPA with a zinc compound. For example, a dithiophosphoric
acid may be made by reacting mixtures of primary and secondary
alcohols. Alternatively, multiple dithiophosphoric acids can be
prepared where the hydrocarbyl groups on one are entirely secondary
in character and the hydrocarbyl groups on the others are entirely
primary in character. To make the zinc salt, any basic or neutral
zinc compound could be used but the oxides, hydroxides and
carbonates are most often employed. Commercial additives frequently
contain an excess of zinc due to the use of an excess of the basic
zinc compound in the neutralization reaction.
[0079] In one embodiment, the oil soluble zinc
dialkyldithiophosphates may be produced from
dialkykyldithiophosphoric acids (DDPA) of the formula:
##STR00004##
[0080] The hydroxyl alkyl compounds from which the
dialkyldithiophosphoric acids are derived can be represented
generically by the formula ROH or R'OH, wherein R or R' is alkyl or
substituted alkyl, in one embodiment, branched or non-branched
alkyl containing 3 to 30 carbon atoms. In another embodiment, R or
R' is a branched or non-branched alkyl containing 3 to 8 carbon
atoms. Examples of alkyl groups include a straight or branched
ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl,
undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,
heptadecyl, and octadecyl groups.
[0081] In certain embodiments, the dialkyldithiophosphoric acids
are prepared from mono-, di-, tri-, tetra-, and other polyhydroxy
alkyl compounds, or mixtures of two or more of the foregoing. In
one embodiment, the zinc dialkyldithiophosphate is derived from a
single primary alcohol. In one embodiment, the single primary
alcohol is 2-ethylhexanol. In one embodiment, the zinc
dialkyldithiophosphate is derived from one or more secondary alkyl
alcohols. In one embodiment, the mixture of secondary alcohols is a
mixture of 2-butanol and 4-methyl-2-pentanol.
[0082] The zinc salts can be prepare from the dihydrocarbyl
dithiophosphoric acids by reacting with a zinc compound. In some
embodiments, a basic or a neutral zinc compound is used. In other
embodiments, an oxide, hydroxide or carbonate of zinc is used.
[0083] The phosphorus pentasulfide reactant used in the
dialkyldithiophosphoric acid formation step may contain certain
amounts of one or more of P.sub.2S.sub.3, P.sub.4S.sub.3,
P.sub.4S.sub.7, or P.sub.4S.sub.9. Compositions as such may also
contain minor amounts of free sulfur. In certain embodiments, the
phosphorus pentasulfide reactant is substantially free of any of
P.sub.2S.sub.3, P.sub.4S.sub.3, P.sub.4S.sub.7, and P.sub.4S.sub.9.
In certain embodiments, the phosphorus pentasulfide reactant is
substantially free of free sulfur.
[0084] The phosphorus content derived from the zinc
dialkyldithiophosphate compound is about 200 to 500 ppm based on
the total weight of the lubricating oil composition. In certain
embodiments, the phosphorus content derived from the zinc
dialkyldithiophosphate compound is about 200 to 400 ppm. In one
embodiment, the phosphorus content derived from the zinc
dialkyldithiophosphate compound is about 200, 250, 300, 350, 400,
450, 500 ppm. In one embodiment, phosphorus content derived from
the zinc dialkyldithiophosphate compound is about 250 ppm.
[0085] The following additive components are examples of some of
the components that can be favorably employed in the present
invention. These examples of additives are provided to illustrate
the present invention, but they are not intended to limit it:
[0086] 1) Metal Detergents
[0087] In some embodiments, the lubricating oil composition
provided herein comprises at least a neutral or overbased metal
detergent as an additive, or additive components. In certain
embodiments, the metal detergents in lubricating oil compositions
acts as a neutralizer of acidic products within the oil. In certain
embodiments, the metal detergent prevents the formation of deposits
on the surface of an engine. Depending on the nature of the acid
used, the detergent may have additional functions, for example,
antioxidant properties. In certain aspects, lubricating oil
compositions contain metal detergents comprising either overbased
detergents or mixtures of neutral and overbased detergents. The
term "overbased" is intended to define additives which contain a
metal content in excess of that required by the stoichiometry of
the particular metal and the particular organic acid used. The
excess metal exists in the form of particles of inorganic base,
e.g. a hydroxide or carbonate, surrounded by a sheath of metal
salt. The sheath serves to maintain the particles in dispersion in
a liquid oleaginous vehicle. The amount of excess metal is commonly
expressed as the ratio of total equivalence of excess metal to
equivalence of organic acid and is typically 0.1 to 30.
[0088] Some non-limiting examples of suitable metal detergents
include sulfurized or unsulfurized alkyl or alkenyl phenates, alkyl
or alkenyl aromatic sulfonates, borated sulfonates, sulfurized or
unsulfurized metal salts of multi-hydroxy alkyl or alkenyl aromatic
compounds, alkyl or alkenyl hydroxy aromatic sulfonates, sulfurized
or unsulfurized alkyl or alkenyl naphthenates, metal salts of
alkanoic acids, metal salts of an alkyl or alkenyl multiacid, and
chemical and physical mixtures thereof. Other non-limiting examples
of suitable metal detergents include metal sulfonates, phenates,
salicylates, phosphonates, thiophosphonates and combinations
thereof. The metal can be any metal suitable for making sulfonate,
phenate, salicylate or phosphonate detergents. Non-limiting
examples of suitable metals include alkali metals, alkaline metals
and transition metals. In some embodiments, the metal is Ca, Mg,
Ba, K, Na, Li or the like. An exemplary metal detergent which may
be employed in the lubricating oil compositions includes overbased
calcium phenate.
[0089] Generally, the amount of the metal detergent additive can be
less than 10000 ppm, less than 1000 ppm, less than 100 ppm, or less
than 10 ppm, based on the total weight of the lubricating oil
composition. In some embodiments, the amount of the metal detergent
is from about 0.001 wt. % to about 5 wt. %, from about 0.05 wt. %
to about 3 wt. %, or from about 0.1 wt. % to about 1 wt. %, based
on the total weight of the lubricating oil composition. Some
suitable detergents have been described in Mortier et al.,
"Chemistry and Technology of Lubricants," 2nd Edition, London,
Springer, Chapter 3, pages 75-85 (1996); and Leslie R. Rudnick,
"Lubricant Additives: Chemistry and Applications," New York, Marcel
Dekker, Chapter 4, pages 113-136 (2003), both of which are
incorporated herein by reference.
[0090] 2) Anti Wear and/or Extreme Pressure Agents
[0091] In certain embodiments, the lubricating oil compositions
disclosed herein can additionally comprise anti wear or extreme
pressure agents. Wear occurs in all equipment that has moving parts
in contact. Specifically, three conditions commonly lead to wear in
engines: (1) surface-to-surface contact; (2) surface contact with
foreign matter; and (3) erosion due to corrosive materials. Wear
resulting from surface-to-surface contact is friction or adhesive
wear, from contact with foreign matter is abrasive wear, and from
contact with corrosive materials is corrosive wear. Fatigue wear is
an additional type of wear that is common in equipment where
surfaces are not only in contact but also experience repeated
stresses for prolonged periods. Abrasive wear can be prevented by
installing an efficient filtration mechanism to remove the
offending debris. Corrosive wear can be addressed by using
additives which neutralize the reactive species that would
otherwise attack the metal surfaces. The control of adhesive wear
requires the use of additives called antiwear and extreme-pressure
(EP) agents.
[0092] Under optimal conditions of speed and load, the metal
surfaces of the equipment should be effectively separated by a
lubricant film. Increasing load, decreasing speed, or otherwise
deviating from such optimal conditions promote metal-to-metal
contact. This contact typically causes a temperature increase in
the contact zone due to frictional heat, which in turn leads to the
loss of lubricant viscosity and hence its film-forming ability. In
certain embodiments, antiwear additive and EP agents offer
protection by a similar mechanism. In certain embodiments, EP
additives require higher activation temperatures and load than
antiwear additives.
[0093] Without being bound to any particular theory, it is believed
that antiwear and/or EP additives function by thermal decomposition
and by forming products that react with the metal surface to form a
solid protective layer. This solid metal film fills the surface
asperities and facilitates effective film formation, thereby
reducing friction and preventing welding and surface wear.
[0094] Most antiwear and extreme pressure agents contain sulfur,
chlorine, phosphorus, boron, or combinations thereof. The classes
of compounds that inhibit adhesive wear include, for example, alkyl
and aryl disulfides and polysulfides; dithiocarbamates; chlorinated
hydrocarbons; and phosphorus compounds such as alkyl phosphites,
phosphates, dithiophosphates, and alkenylphosphonates.
[0095] Exemplary antiwear agents that can be included in the
lubricant oil compositions provided herein include metal (e.g., Pb,
Sb, and the like) salts of dithiophosphate, metal (e.g., Pb, Sb,
and the like) salts of dithiocarbamate, metal (e.g., Pb, Sb and the
like) salts of fatty acids, boron compounds, phosphate esters,
phosphite esters, amine salts of phosphoric acid esters or
thiophosphoric acid esters, reaction products of dicyclopentadiene
and thiophosphoric acids and combinations thereof. The amount of
the anti-wear agent may vary from about 0.01 wt. % to about 5 wt.
%, from about 0.05 wt. % to about 3 wt. %, or from about 0.1 wt. %
to about 1 wt. %, based on the total weight of the lubricating oil
composition. Some suitable anti-wear agents have been described in
Leslie R. Rudnick, "Lubricant Additives: Chemistry and
Applications," New York, Marcel Dekker, Chapter 8, pages 223-258
(2003), which is incorporated herein by reference.
[0096] In one embodiment, the sulfated ash content of the total
lubricating oil composition is less than 5 wt. %, less than 4 wt.
%, less than 3 wt. %, less than 2 wt. %, or less than 1 wt. %, as
measured according to ASTM D874.
[0097] In one embodiment, the EP agents for use in the lubricant
oil compositions include alkyl and aryl disulfides and
polysulfides, dithiocarbamates, chlorinated hydrocarbons, dialkyl
hydrogen phosphites, and salts of alkyl phosphoric acids. Methods
of making these EP agents are known in the art. For example,
polysulfides are synthesized from olefins either by reacting with
sulfur or sulfur halides, followed by dehydrohalogenation.
Dialkydithiocarbamates are prepared either by neutralizing
dithiocarbamic acid (which can be prepared by reacting a
diakylamine and carbon disulfide at low temperature) with bases,
such as antimony oxided, or by its addition to activated olefins,
such as alkyl acrylates.
[0098] In certain embodiments, the lubricating oil compositions
comprise one or more EP agents. In one embodiment, use of more that
one EP agent leads to synergism. For example, synergism may be
observed between sulfur and chlorine-containing EP agents. An
exemplary lubricating oil composition provided herein includes one
or more EP agents selected from: zinc dialkyldithiophosphate
(primary alkyl type & secondary alkyl type), sulfurized oils,
diphenyl sulfide, methyl trichlorostearate, chlorinated
naphthalene, fluoroalkylpolysiloxane, and lead naphthenate.
[0099] 3. Rust Inhibitors (Anti Rust Agents)
[0100] Protection against rust is an important consideration in
formulating lubricants. Without protection, rust ultimately causes
a loss of metal, thereby lowering the integrity of the equipment,
and resulting in engine mal-function. In addition, corrosion
exposes fresh metal that can wear at an accelerated rate,
perpetuated by the metal ions that might be released into the fluid
and act as oxidation promoters.
[0101] The lubricating oil composition disclosed herein can
optionally comprise a rust inhibitor that can inhibit the corrosion
of metal surfaces. Any rust inhibitor known by a person of ordinary
skill in the art may be used in the lubricating oil composition.
The rust inhibitors attach themselves to metal surfaces to form an
impenetrable protective film, which can be physically or chemically
adsorbed to the surface. Specifically, film formation occurs when
the additives interact with the metal surface via their polar ends
and associate with the lubricant via their nonpolar ends. Suitable
rust inhibitors may include, for example, various nonionic
polyoxyethylene surface active agents such as polyoxyethylene
lauryl ether, polyoxyethylene higher alcohol ether, polyoxyethylene
nonylphenyl ether, polyoxyethylene octylphenyl ether,
polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl ether,
polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol
mono-oleate, and polyethylene glycol monooleate. Suitable rust
inhibitors may further include other compounds such as, for
example, monocarboxylic acids (e.g., 2-ethylhexanoic acid, lauric
acid, myristic acid, palmitic acid, oleic acid, linoleic acid,
linolenic acid, behenic acid, cerotic acid and the like),
oil-soluble polycarboxylic acids (e.g., those produced from tall
oil fatty acids, oleic acid, linoleic acid and the like),
alkenylsuccinic acids in which the alkenyl group contains 10 or
more carbon atoms (e.g., tetrapropenylsuccinic acid,
tetradecenylsuccinic acid, hexadecenylsuccinic acid, and the like);
long-chain alpha,omega-dicarboxylic acids having a molecular weight
in the range of 600 to 3000 daltons and combinations thereof.
Further examples of rust agents include metal soaps, fatty acid
amine salts, metal salts of heavy sulfonic acid, partial carboxylic
acid ester of polyhydric alcohol, and phosphoric ester.
[0102] 4. Demulsifiers
[0103] The lubricating oil composition disclosed herein can
optionally comprise a demulsifier that can promote oil-water
separation in lubricating oil compositions that are exposed to
water or steam. Any demulsifier known by a person of ordinary skill
in the art may be used in the lubricating oil composition.
Non-limiting examples of suitable demulsifiers include anionic
surfactants (e.g., alkyl-naphthalene sulfonates, alkyl benzene
sulfonates and the like), nonionic alkoxylated alkylphenol resins,
polymers of alkylene oxides (e.g., polyethylene oxide,
polypropylene oxide, block copolymers of ethylene oxide, propylene
oxide and the like), esters of oil soluble acids, polyoxyethylene
sorbitan ester and combinations thereof In certain embodiments, the
demulsifiers for use herein include block copolymers of propylene
oxide or ethylene oxide and initiators, such as, for example,
glycerol, phenol, formaldehyde resins, soloxanes, polyamines, and
polyols. In certain embodiments, the polymers contain about 20 to
about 50% ethylene oxide. These materials concentrate at the
water-oil interface and create low viscosity zones, thereby
promoting droplet coalescence and gravity-driven phase separation.
Low molecular weight materials, such as, for example, alkali metal
or alkaline earth metal salts of dialkylnaphthalene sulfonic acids,
are also useful in certain applications. The amount of the
demulsifier may vary from about 0.01 wt. % to about 10 wt. %, from
about 0.05 wt. % to about 5 wt. %, or from about 0.1 wt. % to about
3 wt. %, based on the total weight of the lubricating oil
composition. Some suitable demulsifiers have been described in
Mortier et al., "Chemistry and Technology of Lubricants," 2nd
Edition, London, Springer, Chapter 6, pages 190-193 (1996), which
is incorporated herein by reference.
[0104] 5. Friction Modifiers
[0105] The lubricating oil composition disclosed herein can
optionally comprise a friction modifier that can lower the friction
between moving parts. Any friction modifier known by a person of
ordinary skill in the art may be used in the lubricating oil
composition. They are typically long-chain molecules with a polar
end group and a nonpolar linear hydrocarbon chain. The polar end
groups either physically adsorb onto the metal surface or
chemically react with it, while the hydrocarbon chain extend into
the lubricant. The chains associated with one another and the
lubricant to form a strong lubricant film.
[0106] Non-limiting examples of suitable friction modifiers include
fatty carboxylic acids; derivatives (e.g., alcohol, esters, borated
esters, amides, metal salts and the like) of fatty carboxylic acid;
mono-, di- or tri-alkyl substituted phosphoric acids or phosphonic
acids; derivatives (e.g., esters, amides, metal salts and the like)
of mono-, di- or tri-alkyl substituted phosphoric acids or
phosphonic acids; mono-, di- or tri-alkyl substituted amines; mono-
or di-alkyl substituted amides and combinations thereof.
[0107] In one embodiment, the friction modifier is a saturated
fatty acid containing a 13 to 18 carbon chains. The amount of the
friction modifier may vary from about 0.01 wt. % to about 10 wt. %,
from about 0.05 wt. % to about 5 wt. %, or from about 0.1 wt. % to
about 3 wt. %, based on the total weight of the lubricating oil
composition. Some suitable friction modifiers have been described
in Mortier et al., "Chemistry and Technology of Lubricants," 2nd
Edition, London, Springer, Chapter 6, pages 183-187 (1996); and
Leslie R. Rudnick, "Lubricant Additives: Chemistry and
Applications," New York, Marcel Dekker, Chapters 6 and 7, pages
171-222 (2003), both of which are incorporated herein by
reference.
[0108] 6. Pour Point Depressants
[0109] The lubricating oil composition disclosed herein can
optionally comprise a pour point depressant that can lower the pour
point of the lubricating oil composition. Any pour point depressant
known by a person of ordinary skill in the art may be used in the
lubricating oil composition. In certain embodiments, pour point
depressants possess one or more structural features selected from:
(1) polymeric structure; (2) waxy and non-waxy components; (3) comb
structure comprising a short backbone with long pendant groups; and
(4) broad molecular weight distribution. Non-limiting examples of
suitable pour point depressants include polymethacrylates, alkyl
acrylate polymers, alkyl methacrylate polymers, alkyl fumarate
polymers, di(tetra-paraffin phenol)phthalate, condensates of
tetra-paraffin phenol, condensates of a chlorinated paraffin with
naphthalene, alkylated naphthalenes, styrene esters, oligomerized
alkyl phenols, phthalic acid esters, ethylene-vinyl acetate
copolymers and combinations thereof. In one embodiment, the pour
point depressant is selected from tetra (long-chain) alkyl
silicates, phenyltrstearyloxysilane, and pentaerythritol
tetrastearate. In some embodiments, the pour point depressant
comprises an ethylene-vinyl acetate copolymer, a condensate of
chlorinated paraffin and phenol, polyalkyl styrene or the like. The
amount of the pour point depressant may vary from about 0.01 wt. %
to about 10 wt. %, from about 0.05 wt. % to about 5 wt. %, or from
about 0.1 wt. % to about 3 wt. %, based on the total weight of the
lubricating oil composition. Some suitable pour point depressants
have been described in Mortier et al., "Chemistry and Technology of
Lubricants," 2nd Edition, London, Springer, Chapter 6, pages
187-189 (1996); and Leslie R. Rudnick, "Lubricant Additives:
Chemistry and Applications," New York, Marcel Dekker, Chapter 11,
pages 329-354 (2003), both of which are incorporated herein by
reference.
[0110] 7. Foam Inhibitors
[0111] The lubricating oil composition disclosed herein can
optionally comprise a foam inhibitor or an anti-foam that can break
up foams in oils. Any foam inhibitor or anti-foam known by a person
of ordinary skill in the art may be used in the lubricating oil
composition. Non-limiting examples of suitable anti-foams include
silicone oils or polydimethylsiloxanes, fluorosilicones,
alkoxylated aliphatic acids, polyethers (e.g., polyethylene
glycols), branched polyvinyl ethers, alkyl acrylate polymers, alkyl
methacrylate polymers, polyalkoxyamines and combinations thereof.
In some embodiments, the anti-foam comprises glycerol monostearate,
polyglycol palmitate, a trialkyl monothiophosphate, an ester of
sulfonated ricinoleic acid, benzoylacetone, methyl salicylate,
glycerol monooleate, or glycerol dioleate. The amount of the
anti-foam may vary from about 0.01 wt. % to about 5 wt. %, from
about 0.05 wt. % to about 3 wt. %, or from about 0.1 wt. % to about
1 wt. %, based on the total weight of the lubricating oil
composition. Some suitable anti-foams have been described in
Mortier et al., "Chemistry and Technology of Lubricants," 2nd
Edition, London, Springer, Chapter 6, pages 190-193 (1996), which
is incorporated herein by reference.
[0112] 8. Metal Deactivators
[0113] In some embodiments, the lubricating oil composition
comprises at least a metal deactivator. Some non-limiting examples
of suitable metal deactivators include disalicylidene
propylenediamine, triazole derivatives, thiadiazole derivatives,
and mercaptobenzimidazoles.
[0114] 9. Dispersants
[0115] The lubricating oil composition disclosed herein can
optionally comprise a dispersant that can prevent sludge, varnish,
and other deposits by keeping particles suspended in a colloidal
state. In certain embodiments, dispersants perform these functions
via one or more means selected from: (1) solubilizing polar
contaminants in their micelles; (2) stabilizing colloidal
dispersions in order to prevent aggregation of their particles and
their separation out of oil; (3) suspending such products, if they
form, in the bulk lubricant; (4) modifying soot to minimize its
aggregation and oil thickening; and (5) lowering
surface/interfacial energy of undesirable materials to decrease
their tendency to adhere to surfaces. The undesirable materials are
typically formed as a result of oxidative degradation of the
lubricant, the reaction of chemically reactive species such as
carboxylic acids with the metal surfaces in the engine, or the
decomposition of thermally unstable lubricant additives such as,
for example, extreme pressure agents.
[0116] In certain aspects, a dispersant molecule comprises three
distinct structural features: (1) a hydrocarbyl group; (2) a polar
group; and (3) a connecting group or a link. In certain
embodiments, the hydrocarbyl group is polymeric in nature, and has
a molecular weight of at or above about 2000 Daltons, in one
embodiment, at or above about 3000 Daltons, in another embodiment,
at or above about 5000 Daltons, and in yet another embodiment, at
or above about 8000 Daltons. A variety of olefins, such as
polyisobutylene, polypropylene, polyalphaolefins, and mixtures
thereof, can be used to make suitable polymeric dispersants. In
certain embodiments, the polymeric dispersant is a
polyisobutylene-derived dispersant. Typically the number average
molecular weight of polyisobutylene in those dispersants ranges
between about 500 and about 3000 Daltons, or, in some embodiments,
between about 800 to about 2000 Daltons, or in further embodiments,
between about 1000 to about 2000 Daltons. In certain embodiments,
the polar group in the dispersant is nitrogen- or oxygen-derived.
Nitrogen-based dispersants are typically derived from amines. The
amines from which the nitrogen-based dispersants are derived are
often polyalkylenepolyamines, such as, for example,
diethylenetriamine and trethylenetetramine. Amine-derived
dispersants are also called nitrogen- or amine-dispersants, while
those derived from alcohol are also called oxygen or ester
dispersants. Oxygen-based dispersants are typically neutral while
the amine-based dispersants are typically basic.
[0117] Non-limiting examples of suitable dispersants include
alkenyl succinimides, alkenyl succinimides modified with other
organic compounds, alkenyl succinimides modified by post-treatment
with ethylene carbonate or boric acid, succiamides, succinate
esters, succinate ester-amides, pentaerythritols,
phenate-salicylates and their post-treated analogs, alkali metal or
mixed alkali metal, alkaline earth metal borates, dispersions of
hydrated alkali metal borates, dispersions of alkaline-earth metal
borates, polyamide ashless dispersants, benzylamines, Mannich type
dispersants, phosphorus-containing dispersants, and combinations
thereof. The amount of the dispersant may vary from about 0.01 wt.
% to about 10 wt. %, from about 0.05 wt. % to about 7 wt. %, or
from about 0.1 wt. % to about 4 wt. %, based on the total weight of
the lubricating oil composition. Some suitable dispersants have
been described in Mortier et al., "Chemistry and Technology of
Lubricants," 2nd Edition, London, Springer, Chapter 3, pages 86-90
(1996); and Leslie R. Rudnick, "Lubricant Additives: Chemistry and
Applications," New York, Marcel Dekker, Chapter 5, pages 137-170
(2003), both of which are incorporated herein by reference.
[0118] 10. Anti-Oxidants
[0119] Optionally, the lubricating oil composition disclosed herein
can further comprise an additional antioxidant that can reduce or
prevent the oxidation of the base oil. Any antioxidant known by a
person of ordinary skill in the art may be used in the lubricating
oil composition. Examples of anti oxidants useful in the
compositions include, but are not limited to, phenol type
(phenolic) oxidation inhibitors, such as 4,4' methylene bis(2,6 di
tert butylphenol), 4,4' bis(2,6 di tert-butylphenol), 4,4' bis(2
methyl 6 tert butylphenol), 2,2' methylene bis(4-methyl 6 tert
butylphenol), 4,4' butylidene bis(3 methyl 6 tert butylphenol),
4,4' isopropylidene bis(2,6 di tert butylphenol), 2,2' methylene
bis(4-methyl 6 nonylphenol), 2,2' isobutylidene bis(4,6
dimethylphenol), 2,2' 5 methylene bis(4 methyl 6 cyclohexylphenol),
2,6 di tert butyl 4-methylphenol, 2,6 di tert butyl 4 ethylphenol,
2,4 dimethyl 6 tert butyl-phenol, 2,6 di tert 1 dimethylamino p
cresol, 2,6 di tert 4 (N,N'-dimethylaminomethylphenol), 4,4'
thiobis(2 methyl 6 tert butylphenol), 2,2'-thiobis(4 methyl 6 tert
butylphenol), bis(3 methyl 4 hydroxy 5 tert-10 butylbenzyl)sulfide,
and bis(3,5 di tert butyl 4 hydroxybenzyl). Diphenylamine type
oxidation inhibitors include, but are not limited to, alkylated
diphenylamine, phenyl alpha naphthylamine, and alkylated alpha
naphthylamine, sulfur-based antioxidants (e.g.,
dilauryl-3,3'-thiodipropionate, sulfurized phenolic antioxidants
and the like), phosphorous-based antioxidants (e.g., phosphites and
the like), zinc dithiophosphate, oil-soluble copper compounds and
combinations thereof. Other types of oxidation inhibitors include
metal dithiocarbamate (e.g., zinc dithiocarbamate), and 15
methylenebis(dibutyldithiocarbamate). The amount of the antioxidant
may vary from about 0.01 wt. % to about 10 wt. %, from about 0.05
wt. % to about 5 wt. %, or from about 0.1 wt. % to about 3 wt. %,
based on the total weight of the lubricating oil composition. Some
suitable antioxidants have been described in Leslie R. Rudnick,
"Lubricant Additives: Chemistry and Applications," New York, Marcel
Dekker, Chapter 1, pages 1-28 (2003), which is incorporated herein
by reference.
[0120] 11. Multifunctional Additives
[0121] Various additives mentioned or not mentioned herein can
provide a multiplicity of effects to the lubricant oil composition
provided herein. Thus, for example, a single additive may act as a
dispersant as well as an oxidative inhibitor. Multi-functional
additives are well known in the art. Other suitable
multi-functional additives may include, for example, sulfurized
oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum organo
pohosphoro dithioate, oxymolybdenum monoglyceride, amine-molybdenum
complex compound, and sulfur-containing molybdenym complex
compounds.
[0122] 12. Viscosity Index Improvers
[0123] In certain embodiments, the lubricating oil composition
comprises at least a viscosity index improver. Some non-limiting
examples of suitable viscosity index improvers include
polymethacrylate type polymers, ethylene-propylene copolymers,
styrene-isoprene copolymers, hydrated styrene-isoprene copolymers,
polyisobutylene, and dispersant type viscosity index improvers.
[0124] Processes of Preparing Lubricating Oil Compositions
[0125] The lubricating oil compositions disclosed herein can be
prepared by any method known to a person of ordinary skill in the
art for making lubricating oils. In some embodiments, the base oil
is blended or mixed with an oil-soluble molybdenum compound; a zinc
dialkyldithiophosphate and optionally an additive. In certain
embodiments, the oil-soluble molybdenum compound; a zinc
dialkyldithiophosphate are premixed followed by addition of the
base oil. In other embodiments, the oil-soluble molybdenum compound
and zinc dialkyldithiophosphate can be added to the base oil
individually or simultaneously. In some embodiments, the
oil-soluble molybdenum compound, zinc dialkyldithiophosphate and
the optional additives are added to the base oil individually in
one or more additions and the additions may be in any order. In
other embodiments, the ester base stocks and the additives are
added to the base oil simultaneously. In some embodiments, the
oil-soluble molybdenum compound, zinc dialkyldithiophosphate and
the optional additives are premixed and the premix is added to the
base oil along with a viscosity index improver.
[0126] Any mixing or dispersing equipment known to a person of
ordinary skill in the art may be used for blending, mixing or
solubilizing the ingredients. The blending, mixing or solubilizing
may be carried out with a blender, an agitator, a disperser, a
mixer (e.g., planetary mixers and double planetary mixers), a
homogenizer (e.g., Gaulin homogenizers and Rannie homogenizers), a
mill (e.g., colloid mill, ball mill and sand mill) or any other
mixing or dispersing equipment known in the art.
[0127] Applications of the Lubricating Oil Compositions
[0128] In certain embodiments, the lubricating oil compositions
provided herein is suitable for use as motor oils (that is, engine
oils or crankcase oils), in a gasoline or diesel engine.
[0129] In one embodiment, the lubricating oil composition provided
herein is used to cool hot engine parts, keep the engine free of
rust and deposits, and seal the rings and valves against leakage of
combustion gases. The motor oil composition comprises a base oil,
oil-soluble molybdenum compound and a zinc dialkyldithiophosphate.
Optionally, the motor oil composition may further comprises one or
more other additives. In some embodiments, the motor oil
composition further comprises a pour point depressant, a detergent,
a dispersant, an anti-wear, an antioxidant, a friction modifier, a
rust inhibitor, or a combination thereof.
[0130] The following examples are presented to exemplify
embodiments of the lubricant oil compositions provided herein but
are not intended to limit the subject matter to the specific
embodiments set forth. Unless indicated to the contrary, all parts
and percentages are by weight. All numerical values are
approximate. When numerical ranges are given, it should be
understood that embodiments outside the stated ranges may still
fall within the scope of the claimed subject matter. Specific
details described in each example should not be construed as
necessary features of the claimed subject matter.
EXAMPLES
Example 1
[0131] A lubricating oil composition was prepared and used for
assessing boundary lubrication properties in the High Frequency
Reciprocating Rig (HFRR) test (ASTM D 6079). The composition
contained a major amount of a base oil of lubricating viscosity and
the following additives, to provide an SAE 5W-20 finished oil;
[0132] (1) 700 ppm in terms of molybdenum content, of a molybdenum
dithiocarbamate
[0133] (2) 1 wt % of a borated bis-succinimide dispersant
[0134] (3) 4 wt % of an ethylene carbonate post-treated
bis-succinimide
[0135] (4) 164 ppm in terms of calcium content, of a 17 TBN calcium
sulfonate detergent
[0136] (5) 2220 ppm in terms of calcium content, of a 148 TBN
calcium salicylate
[0137] (6) 1 wt % of an alkylated diphenylamine
[0138] (7) 0.2 wt % of hindered phenol
[0139] (8) 0.2 wt % of a pour point depressant
[0140] (9) 4.8 wt % of a non-dispersant ethylene-propylene
copolymer concentrate
[0141] (10) 5 ppm in terms of Silicon content, of a foam
inhibitor
[0142] (11) The remainder was diluent oil. Diluent oil can be a Gp
1 or Gp 2 base oil. However, any diluent oil known to one of skill
in the art could be used.
Example 2
[0143] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that 250 ppm in terms of phosphorus
content of a zinc dialkyldithiophosphate was added. The composition
contained 250 ppm phosphorus based on the total weight of the
lubricating oil composition.
[0144] The zinc dialkyldithiophosphate is synthesized using a
mixture of C4 and C6 secondary alcohols. The resulting zinc
dialkyldithiophosphate is a zinc
bis(O,O'-di-(2-butyl/4-methyl-2-pentyl)dithiophosphate.
Example 3
[0145] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that 500 ppm in terms of phosphorus
content of the zinc dialkyldithiophosphate was added. The
composition contained 500 ppm phosphorus based on the total weight
of the lubricating oil composition.
Example 4
[0146] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that 750 ppm in terms of phosphorus
content of the zinc dialkyldithiophosphate was added. The
composition contained 750 ppm phosphorus based on the total weight
of the lubricating oil composition.
Example 5
[0147] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that 1000 ppm in terms of
phosphorus content of the zinc dialkyldithiophosphate was added.
The composition contained 1000 ppm phosphorus based on the total
weight of the lubricating oil composition.
Example 6
[0148] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that 700 ppm inter ms of molybdenum
content of an oxymolybdenum-succinimide complex was used in place
of the molybdenum dithiocarbamate.
Example 7
[0149] A lubricating oil was prepared in accordance with the
formulation of Example 6 except that 250 ppm in terms of phosphorus
content of the zinc dialkyldithiophosphate was added. The
composition contained 250 ppm phosphorus based on the total weight
of the lubricating oil composition.
Example 8
[0150] A lubricating oil was prepared in accordance with the
formulation of Example 6 except that 500 ppm in terms of phosphorus
content of the zinc dialkyldithiophosphate was added. The
composition contained 500 ppm phosphorus based on the total weight
of the lubricating oil composition.
Example 9
[0151] A lubricating oil was prepared in accordance with the
formulation of Example 6 except that 750 ppm in terms of phosphorus
content of the zinc dialkyldithiophosphate was added. The
composition contained 750 ppm phosphorus based on the total weight
of the lubricating oil composition.
Example 10
[0152] A lubricating oil was prepared in accordance with the
formulation of Example 6 except that 1000 ppm in terms of
phosphorus content of the zinc dialkyldithiophosphate was added.
The composition contained 1000 ppm phosphorus based on the total
weight of the lubricating oil composition.
Example 11
[0153] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that the amount of molybdenum
dithiocarbamate was reduced to 150 ppm in terms of molybdenum
content, and 550 ppm in terms of molybdenum content of the
oxymolybdenum-succinimide complex was added.
Example 12
[0154] A lubricating oil was prepared in accordance with the
formulation of Example 11 except that 250 ppm in terms of
phosphorus content of the zinc dialkyldithiophosphate was added.
The composition contained 250 ppm phosphorus based on the total
weight of the lubricating oil composition.
Example 13
[0155] A lubricating oil was prepared in accordance with the
formulation of Example 11 except that 500 ppm in terms of
phosphorus content of the zinc dialkyldithiophosphate was added.
The composition contained 500 ppm phosphorus based on the total
weight of the lubricating oil composition.
Example 14
[0156] A lubricating oil was prepared in accordance with the
formulation of Example 11 except that 750 ppm in terms of
phosphorus content of the zinc dialkyldithiophosphate was added.
The composition contained 750 ppm phosphorus based on the total
weight of the lubricating oil composition.
Example 15
[0157] A lubricating oil was prepared in accordance with the
formulation of Example 10 except that 1000 ppm in terms of
phosphorus content of the zinc dialkyldithiophosphate was added.
The composition contained 1000 ppm phosphorus based on the total
weight of the lubricating oil composition.
Test Procedure
[0158] The High Frequency Reciprocating Rig (HFRR) test (ASTM D
6079) is designed to evaluate boundary lubrication properties. In
this method, a 2 mL sample is placed in the test reservoir of an
HFRR and adjusted to a standard temperature. When the sample
temperature has stabilized, a vibrator arm holding a non-rotating
steel ball is lowered until it contacts a test disk completely
submerged in the sample. The ball is caused to rub against the
disk.
[0159] The compositions of Examples 1-15 were tested using a
120.degree. C. oil reservoir temperature and were subjected to a
1000 g load. The ball was caused to rub against the disk with a 1
mm stroke at a frequency of 20 Hz for 60 min.
[0160] This test was run using samples from Examples 1-15 and the
results are shown in Table 2. A graphic description of these
results is found in FIG. 1.
TABLE-US-00002 TABLE 2 Last 10 Min P.sup.4 Overall Average content
Average Friction Example Mo Source (ppm) Friction Coefficient
Coefficient 1 MoDTC.sup.1 0 0.10 0.068 2 MoDTC.sup.1 250 0.079
0.053 3 MoDTC.sup.1 500 0.083 0.069 4 MoDTC.sup.1 750 0.077 0.071 5
MoDTC.sup.1 1000 0.078 0.076 6 Mo-succ.sup.2 0 0.16 0.16 7
Mo-succ.sup.2 250 0.065 0.050 8 Mo-succ.sup.2 500 0.080 0.058 9
Mo-succ.sup.2 750 0.080 0.064 10 Mo-succ.sup.2 1000 0.086 0.073 11
Mixed.sup.3 0 0.17 0.16 12 Mixed.sup.3 250 0.052 0.052 13
Mixed.sup.3 500 0.083 0.065 14 Mixed.sup.3 750 0.074 0.060 15
Mixed.sup.3 1000 0.076 0.066 .sup.1Lubricating oil compositions
with molybdenum dithiocarbamate had a total molybdenum content of
700 ppm. .sup.2Lubricating oil compositions with
molybdenum-succinimide complex had a total molybdenum content of
700 ppm. .sup.3Lubricating oil composition contained a mixture of
150 ppm Mo of MoDTC and of 550 ppm Mo of molybdenum-succinimide
complex. The lubricating oil composition had a total molybdenum
content of 700 ppm (150 ppm Mo from MoDTC and 550 ppm Mo from
Mo-succinimide complex). .sup.4Phosphorous content in ppm of the
zinc dialkyldithiophosphate employed in Examples 1-15.
[0161] In addition to measurement of the overall average friction
coefficient, the last 10 minute average friction coefficient was
determined. This coefficient is useful because it takes
approximately 15 minutes from the start of the test until there is
a low friction film on the metal surface. Both sets of data show
friction coefficient minima at phosphorus levels of 250 ppm.
[0162] While the lubricant oil compositions provided herein have
been described with respect to a limited number of embodiments, the
specific features of one embodiment should not be attributed to
other embodiments of the subject matter claimed herein. No single
embodiment is representative of all aspects of the claimed subject
matter. In some embodiments, the methods may include numerous steps
not mentioned herein. In other embodiments, the methods do not
include, or are substantially free of, steps not enumerated herein.
Variations and modifications from the described embodiments exist.
It is noted that the methods for producing the compositions
disclosed herein are described with reference to a number of steps.
These steps can be practiced in any sequence. One or more steps may
be omitted or combined but still achieve substantially the same
results. The appended claims intend to cover all such variations
and modifications as falling within the scope of the claims.
[0163] All publications and patent applications mentioned in this
specification are herein incorporated by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by
reference. Although the foregoing has been described in some detail
by way of illustration and example for purposes of clarity of
understanding, it will be readily apparent to those of ordinary
skill in the art in light of the teachings herein that certain
changes and modifications may be made thereto without departing
from the spirit or scope of the appended claims.
* * * * *