U.S. patent application number 11/443940 was filed with the patent office on 2006-12-07 for lubricating oil composition.
Invention is credited to Michael L. Alessi, Nancy Z. Diggs, Jose A. Gutierrez, Matthew D. Irving, Robin Scott.
Application Number | 20060276353 11/443940 |
Document ID | / |
Family ID | 35431264 |
Filed Date | 2006-12-07 |
United States Patent
Application |
20060276353 |
Kind Code |
A1 |
Irving; Matthew D. ; et
al. |
December 7, 2006 |
Lubricating oil composition
Abstract
A method of improving the seal compatibility and/or copper
corrosion performance of lubricating oil compositions for the
lubrication of the crankcases of an internal combustion engine,
which method includes the step of adding to the lubricating oil
compositions a minor amount of a non-hydrogenated (unsaturated)
olefin polymer. Also described are lubricating oil compositions for
engines and transmissions, which compositions contain sulphur
and/or a salicylate soap and a minor amount of a non-hydrogenated
(unsaturated) polymer, which compositions are compatible with
nitrile rubber engine and transmission seals and copper-containing
engine and transmission components.
Inventors: |
Irving; Matthew D.;
(Wantage, GB) ; Scott; Robin; (Abingdon, GB)
; Diggs; Nancy Z.; (Westfield, NJ) ; Gutierrez;
Jose A.; (Fanwood, NJ) ; Alessi; Michael L.;
(Bedminster, NJ) |
Correspondence
Address: |
INFINEUM USA L.P.
P.O. BOX 710
LINDEN
NJ
07036
US
|
Family ID: |
35431264 |
Appl. No.: |
11/443940 |
Filed: |
May 31, 2006 |
Current U.S.
Class: |
508/363 |
Current CPC
Class: |
C10M 161/00 20130101;
C10M 2219/046 20130101; C10N 2030/36 20200501; C10M 2205/026
20130101; C10M 2223/045 20130101; C10M 165/00 20130101; C10M
2219/068 20130101; C10N 2040/04 20130101; C10M 2219/088 20130101;
C10N 2040/252 20200501; C10M 167/00 20130101; C10N 2030/12
20130101; C10N 2010/04 20130101; C10N 2030/42 20200501; C10M
2219/066 20130101; C10M 2219/044 20130101; C10M 2219/089 20130101;
C10N 2010/02 20130101; C10N 2010/12 20130101; C10N 2020/067
20200501; C10M 2207/144 20130101; C10M 2207/262 20130101 |
Class at
Publication: |
508/363 |
International
Class: |
C10M 135/18 20060101
C10M135/18 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 1, 2005 |
EP |
05270020.0 |
Claims
1. A method of improving copper corrosion properties and/or nitrile
seal compatibility in or with a lubricating oil composition
comprising a major amount of oil of lubricating viscosity and a
minor amount of one or more additives, said composition having a
sulfur content of at least 0.1 mass %, based on the total mass of
lubricating oil composition, which method comprises adding to
and/or incorporating into the lubricating oil composition an
effective amount of at least one non-hydrogenated polymer,
preferably an olefin polymer or copolymer, such as polybutene
and/or polyisobutene.
2. The method of claim 1, wherein said effective amount is from 0.2
to 10.0 mass %, based on the total mass of said lubricating oil
composition.
3. The method of claim 2, wherein said effective amount from 1.0 to
2.5 mass %, based on the total mass of said lubricating oil
composition.
4. The method of claim 1 wherein the oil of lubricating viscosity
has a sulfur content of from 0.001 to 0.10 mass %, based on the
total mass of oil of lubricating viscosity, and optionally, at
least one of the said additives comprises a sulfur-containing
compound providing at least 0.005 mass % sulfur, based on the mass
of said composition.
5. The method of claim 4 wherein the oil of lubricating viscosity
has a sulfur content of from 0.005 to 0.05 mass %, based on the
total mass of oil of lubricating viscosity, and optionally, at
least one of the said additives comprises a sulfur-containing
compound providing at least 0.005 mass % sulfur, based on the mass
of said composition.
6. The method of claim 1, wherein at least one additive comprising
a sulfur-containing compound is selected from metal salts of
dihydrocarbyl dithiophosphates, sulfonate detergents, sulfurized
phenate detergents, sulfur-containing molybdenum compounds, ashless
dithiocarbamates, and combinations thereof.
7. The method of claim 1, wherein said lubricating oil composition
has at least one of (a) a sulphated ash (SASH) content of from 0.5
to 1.9 mass and (b) a phosphorus content of less than 1500 ppm,
based on the total mass of the composition.
8. The method of claim 1, wherein said lubricating oil composition
comprises a salicylate detergent in an amount providing said
composition with at least 9 mmoles of salicylate soap per kg of
said composition.
9. The method of claim 1, wherein said lubricating oil composition
comprises a nitrogen-containing dispersant and/or
dispersant-viscosity modifier in an amount providing in said
composition from 0.08 to 0.35 mass % of nitrogen.
10. The method of claim 1, wherein said lubricating oil composition
has a phosphorus content of less than 1500 ppm, based on the total
mass of said composition.
11. The method of claim 10, wherein said lubricating oil
composition has a phosphorus content of from 500 to 1500 ppm, based
on the total mass of said composition.
12. The method of claim 11, wherein said lubricating oil
composition has a phosphorus content of less than 1200 ppm, based
on the total mass of said composition.
13. The method of claim 12, wherein said lubricating oil
composition has a phosphorus content of from 500 to 1200 ppm, based
on the total mass of said composition.
14. The method of claim 13, wherein said lubricating oil
composition has a phosphorus content of from 500 to 850 ppm, based
on the total mass of said composition.
15. The method of claim 1, wherein said oil of lubricating
viscosity comprises at least 50 mass % of mineral oil, based on the
total mass of said composition.
16. The method of claim 1, wherein said composition is a power
transmission fluid or a crankcase lubricating oil composition for
an internal combustion engine.
17. The method of claim 16,wherein said composition is a crankcase
lubricating oil composition for an internal combustion heavy duty
diesel (HDD) engine and said composition meets the performance
requirements of at least ACEA E2-96#5.
18. The method of claim 16, wherein said composition is a crankcase
lubricating oil composition for an internal combustion heavy duty
diesel (HDD) engine and meets the performance requirements of at
least one of ACEA E7-04 and API CI-4.
19. The method of claim 16, wherein said composition is a crankcase
lubricating oil composition for an internal combustion heavy duty
diesel (HDD) engine and meets the performance requirements of at
least one of ACEA E6-04 and API CJ-4.
20. The method of claim 1, wherein the said non-hydrogenated (co-)
polymer has a number average molecular weight in the range of from
450 to 2300.
21. The method of claim 20, wherein the said non-hydrogenated (co-)
polymer has a number average molecular weight in the range of from
450 to 1300.
22. The method of claim 21, wherein the said non-hydrogenated (co-)
polymer has a number average molecular weight in the range of from
450 to 950.
23. A lubricating oil composition comprising a sulfur content of at
least 0.15 mass %, comprising a major amount of an oil of
lubricating viscosity, a minor amount of additive(s) including at
least one additive having sulfur content, and a minor amount of a
non-hydrogenated olefin polymer, and optionally, one or more of the
following: (i) a sulfur-containing additive selected from metal
salts of dihydrocarbyl dithiophosphates, sulfonate detergents,
sulfurized phenate detergents, sulfur-containing molybdenum
compounds, ashless dithiocarbamates, (ii) a sulfated ash (SASH)
content of from 0.5 to 1.9 mass % based on the mass of the
composition; (iii) a phosphorus content of less than 1500 ppm, (iv)
a nitrogen-containing dispersant and/or dispersant-viscosity
modifier providing from 0.08 to 0.35 mass % nitrogen in said
composition; and (v) a salicylate detergent providing at least 9
mmols of salicylate soap per kilogram of composition.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method of improving the
seal-compatibility performance of lubricating oil compositions used
in engine crankcases and transmissions, particularly lubricating
oil compositions having significant sulphur and/or salicylate soap
contents, and to lubricating oil compositions having significant
sulphur and/or salicylate soap contents that exhibit enhanced seals
compatibility performance in engines and transmissions containing
nitrile rubber seal materials. The invention further relates to a
method of improving copper corrosion performance of lubricating oil
compositions used in engine crankcases and transmissions,
particularly lubricating oil compositions having significant
sulphur contents, and to lubricating oil compositions having
significant sulphur contents that exhibit enhanced seals and copper
corrosion performance.
BACKGROUND OF THE INVENTION
[0002] Lubricating oil compositions used to lubricate internal
combustion engines and transmissions contain a major amount of a
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.
Many base oils contain sulfur, and a number of extremely effective
additives conventionally used in engine and transmission
lubricating oil compositions, including zinc dialkyl
dithiophosphates (ZDDP), certain molybdenum-sulfur compounds,
ashless dithiocarbamates and sulfonate and some phenate detergents,
also contain sulfur and contribute to the overall sulfur content of
such formulated lubricants.
[0003] Modern internal combustion engines and transmissions include
numerous gaskets and other seals formed of nitrile rubber
materials. Lubricant sulfur has been found to contribute to the
deterioration of materials. Before certifying a crankcase lubricant
for use in their engines, engine manufacturers (oftentimes referred
to as "original equipment manufacturers or "OEMs") require passage
of a number of performance tests, including tests for compatibility
with engine seal materials. It is also suspected that high levels
of salicylate soap from salicylate detergents may contribute to the
deterioration of nitrile rubber seal materials, particularly in
"low ash" lubricants. Therefore, it would be desirable to provide a
method of improving the seal compatibility of lubricating oil
compositions, particularly lubricating oil compositions having
significant sulfur contents and/or high levels of salicylate soap,
and lubricating oil compositions having significant sulfur contents
and/or high levels of salicylate soap, that provide improved
seal-compatibility performance.
[0004] Lubricant sulfur has been found to cause copper corrosion.
Prior to granting certification, OEMs also require lubricating oil
compositions to pass a copper corrosion test. Therefore, it would
be desirable to provide a method of improving the copper corrosion
performance of lubricating oil compositions, particularly
lubricating oil compositions having significant sulfur contents,
and lubricating oil compositions having significant sulfur contents
that provide improved copper corrosion performance.
SUMMARY OF THE INVENTION
[0005] It has now been found that the addition of a minor amount of
a non-hydrogenated olefin (co)polymer, for example a polyisobutene,
to a lubricating oil composition improves the compatibility between
the lubricating oil composition and nitrile rubber engine and
transmission seals, particularly in lubricating oil compositions
containing a significant amount of sulfur, such as a sulfur content
greater than about 0.10 mass %, such as greater than about 0.15
mass %, particularly greater than about 0.20 mass % and/or
significant amounts of salicylate soap from salicylate detergents,
such as 9 or more, particularly 18 or more, more particularly 24 or
more mmols of salicylate soap per kilogram of finished lubricant.
It has also been found that the addition of a minor amount of a
non-hydrogenated olefin (co)polymer, for example a polyisobutene,
to a lubricating oil composition improves the copper corrosion
performance of lubricating oil compositions, particularly
lubricating oil compositions containing a significant amount of
sulfur, such as a sulfur content greater than about 0.10 mass %,
such as greater than about 0.15 mass %, particularly greater than
about 0.20 mass %.
[0006] Therefore, in a first aspect, the invention is directed to a
method of improving the seal compatibility performance of
lubricating oil compositions for the lubrication of an internal
combustion engine or engine transmission, which method comprises
adding to such lubricating oil compositions a minor amount of a
non-hydrogenated (unsaturated) olefin (co)polymer.
[0007] In a second aspect, the invention is directed to the method
of the first aspect in which the lubricating oil composition
contains a significant sulfur content, such as a sulfur content
greater than about 0.10 mass %, particularly greater than about
0.15 mass %, such as greater than about 0.18 mass %, more
particularly greater than about 0.20 mass %, and comprises a major
amount of oil of lubricating viscosity; a minor amount of at least
one sulphur-containing additive, and from about 0.5 mass % to about
10.0 mass % of a non-hydrogenated olefin (co)polymer, wherein all
mass percentages are based on the total mass of the lubricating oil
composition.
[0008] In a third aspect, the invention is directed to the method
of the first aspect in which the lubricating oil composition
comprises a major amount of oil of lubricating viscosity; a minor
amount of at least one salicylate detergent in an amount
introducing into the lubricating oil composition 9 or more,
particularly 18 or more, more particularly 24 or more mmols of
salicylate soap per kilogram of lubricating oil composition, and
from about 0.5 mass % to about 10.0 mass % of a non-hydrogenated
olefin (co)polymer, wherein all mass percentages are based on the
total mass of the lubricating oil composition.
[0009] In a fourth aspect, the invention is directed to a
lubricating oil composition containing a significant sulfur
content, such as a sulfur content greater than about 0.10 mass %,
particularly greater than about 0.15 mass %, such as greater than
about 0.18 mass %, more particularly greater than about 0.20 mass
%, comprising a major amount of oil of lubricating viscosity; a
minor amount of at least one sulphur-containing additive, and from
about 0.5 mass % to about 10.0 mass % of a non-hydrogenated olefin
(co)polymer, wherein all mass percentages are based on the total
mass of the lubricating oil composition.
[0010] In a fifth aspect, the invention is directed to a
lubricating oil composition comprising a major amount of oil of
lubricating viscosity; a minor amount of at least one salicylate
detergent in an amount introducing into the lubricating oil
composition 9 or more, particularly 18 or more, more particularly
24 or more mmols of salicylate soap per kilogram of lubricating oil
composition (finished lubricant), and from about 0.5 mass % to
about 10.0 mass % of a non-hydrogenated olefin (co)polymer, wherein
all mass percentages are based on the total mass of the lubricating
oil composition.
[0011] In a sixth aspect, the invention is directed to a method of
the second aspect or a lubricating oil composition of the fourth
aspect, wherein the sulphur-containing additives are one or more of
a metal salt of a dihydrocarbyl dithiophosphate (e.g., ZDDP), a
sulfonate detergent, a sulfurized phenate detergent a
molybdenum-sulphur compound and an ashless dithiocarbamate.
[0012] In a seventh aspect, the invention is directed to a method
of the second aspect or a lubricating oil composition of the fourth
aspect, wherein the lubricating oil composition further contains a
salicylate detergent in an amount introducing into the lubricating
oil composition at least about 9 mmols of salicylate soap per
kilogram of finished lubricant and, preferably, has a sulfated ash
content of not greater than about 1.1 mass %, more preferably no
greater than 1.05 mass %.
[0013] In an eighth aspect, the invention is directed to a method
of the third aspect or a lubricating oil composition of the fifth
aspect, wherein the lubricating oil composition contains a
significant sulfur content, such as a sulfur content greater than
about 0.10 mass %, particularly greater than about 0.15 mass %,
such as greater than about 0.18 mass %, more particularly greater
than about 0.20 mass %
[0014] In a ninth aspect, the invention is directed to a method of
improving the copper corrosion performance of lubricating oil
compositions for the lubrication of an internal combustion engine
or engine transmission, which method comprises adding to such
lubricating oil compositions a minor amount of a non-hydrogenated
(unsaturated) olefin (co)polymer.
[0015] In a tenth aspect, the invention is directed to the method
of the ninth aspect in which the lubricating oil composition
contains a significant sulfur content, such as a sulfur content
greater than about 0.10 mass %, particularly greater than about
0.15 mass %, such as greater than about 0.18 mass %, more
particularly greater than about 0.20 mass %, and comprises a major
amount of oil of lubricating viscosity; a minor amount of at least
one sulphur-containing additive, and from about 0.5 mass % to about
10.0 mass % of a non-hydrogenated olefin (co)polymer, wherein all
mass percentages are based on the total mass of the lubricating oil
composition.
[0016] In an eleventh aspect, the invention is directed to the
method of the tenth aspect wherein the sulphur-containing additives
are one or more of a metal salt of a dihydrocarbyl dithiophosphate
(e.g., ZDDP), a sulfonate detergent, a sulfurized phenate detergent
a molybdenum-sulphur compound and an ashless dithiocarbamate.
[0017] In a twelfth aspect, the invention is directed to a
concentrate for preparing a lubricating oil composition of the
fourth aspect comprising an oleaginous carrier, a non-hydrogenated
olefin (co)polymer, and one or more sulfur-containing
additives.
[0018] In a thirteenth aspect, the invention is directed to a
concentrate for preparing a lubricating oil composition of the
fifth aspect comprising an oleaginous carrier, a non-hydrogenated
olefin (co)polymer, and one or more salicylate detergents.
[0019] Other and further objects, advantages and features of the
present invention will be understood by reference to the following
specification.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The lubricating oil compositions of the present invention
are for lubricating the crankcase of an internal combustion engine,
preferably a compression-ignited (diesel) engine, more preferably a
compression-ignited heavy duty diesel engine. Crankcase lubricating
oil compositions for a diesel application, in particular for heavy
duty diesel engines, have to be specifically formulated to meet the
performance requirements for such an application.
[0021] Oils of lubricating viscosity useful in the context of the
present invention may be selected from natural lubricating oils,
synthetic lubricating oils and mixtures thereof. The lubricating
oil may range in viscosity from light distillate mineral oils to
heavy lubricating oils such as gasoline engine oils, mineral
lubricating oils and heavy duty diesel oils. Generally, the
viscosity of the oil ranges from about 2 centistokes to about 40
centistokes, especially from about 4 centistokes to about 20
centistokes, as measured at 100.degree. C.
[0022] Natural oils include animal oils and vegetable oils (e.g.,
castor oil, lard oil); liquid petroleum oils and hydrorefined,
solvent-treated or acid-treated mineral oils of the paraffinic,
naphthenic and mixed paraffinic-naphthenic types. Oils of
lubricating viscosity derived from coal or shale also serve as
useful base oils.
[0023] Synthetic lubricating oils include hydrocarbon oils and
halo-substituted hydrocarbon oils such as polymerized and
interpolymerized olefins (e.g., polybutylenes, polypropylenes,
propylene-isobutylene copolymers, chlorinated polybutylenes,
poly(1-hexenes), poly(1-octenes), poly(1-decenes)); alkylbenzenes
(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,
di(2-ethylhexyl)benzenes); polyphenyls (e.g., biphenyls,
terphenyls, alkylated polyphenols); and alkylated diphenyl ethers
and alkylated diphenyl sulfides and derivative, analogs and
homologs thereof. Also useful are synthetic oils derived from a gas
to liquid process from Fischer-Tropsch synthesized hydrocarbons,
which are commonly referred to as gas to liquid, or "GTL" base
oils.
[0024] Alkylene oxide polymers and interpolymers and derivatives
thereof where the terminal hydroxyl groups have been modified by
esterification, etherification, etc., constitute another class of
known synthetic lubricating oils. These are exemplified by
polyoxyalkylene polymers prepared by polymerization of ethylene
oxide or propylene oxide, and the alkyl and aryl ethers of
polyoxyalkylene polymers (e.g., methyl-polyiso-propylene glycol
ether having a molecular weight of 1000 or diphenyl ether of
poly-ethylene glycol having a molecular weight of 1000 to 1500);
and mono- and polycarboxylic esters thereof, for example, the
acetic acid esters, mixed C.sub.3-C.sub.8 fatty acid esters and
C.sub.13 oxo acid diester of tetraethylene glycol.
[0025] Another suitable class of synthetic lubricating oils
comprises the esters of dicarboxylic acids (e.g., phthalic acid,
succinic acid, alkyl succinic acids and alkenyl succinic acids,
maleic acid, azelaic acid, suberic acid, sebasic acid, fumaric
acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic
acids, alkenyl malonic acids) with a variety of alcohols (e.g.,
butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl
alcohol, ethylene glycol, diethylene glycol monoether, propylene
glycol). Specific examples of such esters includes 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 complex ester formed by reacting one mole of
sebacic acid with two moles of tetraethylene glycol and two moles
of 2-ethylhexanoic acid.
[0026] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.12 monocarboxylic acids and polyols and polyol
esters such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
[0027] Silicon-based oils such as the polyalkyl-, polyaryl-,
polyalkoxy- or polyaryloxysilicone oils and silicate oils comprise
another useful class of synthetic lubricants; such oils include
tetraethyl silicate, tetraisopropyl silicate,
tetra-(2-ethylhexyl)silicate,
tetra-(4-methyl-2-ethylhexyl)silicate, tetra-(p-tert-butyl-phenyl)
silicate, hexa-(4-methyl-2-ethylhexyl)disiloxane,
poly(methyl)siloxanes and poly(methylphenyl)siloxanes. Other
synthetic lubricating oils include liquid esters of
phosphorous-containing acids (e.g., tricresyl phosphate, trioctyl
phosphate, diethyl ester of decylphosphonic acid) and polymeric
tetrahydrofurans.
[0028] Other examples of base oil are gas-to-liquid ("GTL") base
oils, i.e. the base oil may be oil derived from
Fischer-Tropsch-synthesized hydrocarbons made from synthesis gas
containing hydrogen and carbon monoxide using a Fischer-Tropsch
catalyst. These hydrocarbons typically require further processing
in order to be useful as base oil. For example, they may, by
methods known in the art, be hydroisomerized; hydrocracked and
hydroisomerized; dewaxed; or hydroisomerized and dewaxed.
[0029] The oil of lubricating viscosity may comprise a Group I,
Group II or Group III, base stock or base oil blends of the
aforementioned base stocks. Preferably, the oil of lubricating
viscosity is a Group II or Group III base stock, or a mixture
thereof, or a mixture of a Group I base stock and one or more a
Group II and Group III. Preferably, a major amount of the oil of
lubricating viscosity is a Group II, Group m, Group IV or Group V
base stock, or a mixture thereof. In one particular embodiment, it
is preferred that greater than 50 mass %, such as greater than 60
mass % of the oil of lubricating viscosity is mineral oil. The base
stock, or base stock blend preferably has a saturate content of at
least 65%, more preferably at least 75%, such as at least 85%. Most
preferably, the base stock, or base stock blend, has a saturate
content of greater than 90%. Preferably, the oil or oil blend will
have a sulfur content of no greater than 0.5 mass % (e.g., from
about 0.001 to about 0.5 mass %), such as no greater than 0.1 mass
% (e.g., from about 0.001 to about 0.1 mass %), preferably from
about 0.005 to about 0.05 mass %.
[0030] Preferably the volatility of the oil or oil blend, as
measured by the Noack volatility test (ASTM D5880), is less than or
equal to 30 mass %, preferably less than or equal to 25 mass %,
more preferably less than or equal to 20 mass %, most preferably
less than or equal to 16 mass %. Preferably, the viscosity index
(VI) of the oil or oil blend is at least 85, preferably at least
100, most preferably from about 105 to 140.
[0031] Definitions for the base stocks and base oils in this
invention are the same as those found in the American Petroleum
Institute (API) publication "Engine Oil Licensing and Certification
System", Industry Services Department, Fourteenth Edition, December
1996, Addendum 1, December 1998. Said publication categorizes base
stocks as follows: [0032] a) Group I base stocks contain less than
90 percent saturates and/or greater than 0.03 percent sulfur and
have a viscosity index greater than or equal to 80 and less than
120 using the test methods specified in Table I. [0033] b) Group II
base stocks contain greater than or equal to 90 percent saturates
and less than or equal to 0.03 percent sulfur and have a viscosity
index greater than or equal to 80 and less than 120 using the test
methods specified in Table I. [0034] c) Group II base stocks
contain greater than or equal to 90 percent saturates and less than
or equal to 0.03 percent sulfur and have a viscosity index greater
than or equal to 120 using the test methods specified in Table I.
[0035] d) Group IV base stocks are polyalphaolefins (PAO).
[0036] e) Group V base stocks include all other base stocks not
included in Group I, II, III, or IV. TABLE-US-00001 TABLE I
Analytical Methods for Base Stock Property Test Method Saturates
ASTM D 2007 Viscosity Index ASTM D 2270 Sulfur ASTM D 2622 ASTM D
4294 ASTM D 4927 ASTM D 3120
[0037] The non-hydrogenated olefm (co)polymer useful in the
practice of the present invention is preferably a polymer or
copolymer of one or more acyclic olefin monomers. Generally, the
non-hydrogenated olefin (co)polymers useful in the invention have,
or have on average, about one double bond per polymer chain.
[0038] The (co)polymer may be prepared by polymerizing alpha-olefin
monomer, or mixtures of alpha-olefin monomers, or mixtures
comprising ethylene and at least one C.sub.3 to C.sub.28
alpha-olefin monomer, in the presence of a catalyst system
comprising at least one metallocene (e.g., a
cyclopentadienyl-transition metal compound) and an alumoxane
compound. Using this process, a polymer in which 95% or more of the
polymer chains possess terminal ethenylidene-type unsaturation can
be provided. The percentage of polymer chains exhibiting terminal
ethenylidene unsaturation may be determined by FTIR spectroscopic
analysis, titration, or C.sup.13 NMR. Interpolymers of this latter
type may be characterized by the formula
POLY-C(R.sup.1).dbd.CH.sub.2 wherein R.sup.1 is C.sub.1 to C.sub.26
alkyl, preferably C.sub.1 to C.sub.18 alkyl, more preferably
C.sub.1 to C.sub.8 alkyl, and most preferably C.sub.1 to C.sub.2
alkyl, (e.g., methyl or ethyl) and wherein POLY represents the
polymer chain. The chain length of the R.sup.1 alkyl group will
vary depending on the comonomer(s) selected for use in the
polymerization. A minor amount of the polymer chains can contain
terminal ethenyl, i.e. vinyl, unsaturation, i.e.
POLY-CH.dbd.CH.sub.2, and a portion of the polymers can contain
internal monounsaturation, e.g., POLY-CH.dbd.CH(R.sup.1), wherein
R.sup.1 is as defined above. These terminally unsaturated
interpolymers may be prepared by known metallocene chemistry and
may also be prepared as described in U.S. Pat. Nos. 5,498,809;
5,663,130; 5,705,577; 5,814,715; 6,022,929 and 6,030,930.
[0039] Another useful class of (co)polymers is (co)polymers
prepared by cationic polymerization of isobutene, styrene, and the
like. Common (co)polymers from this class include polyisobutenes
obtained by polymerization of a C.sub.4 refinery stream having a
butene content of about 35 to about 75% by wt., and an isobutene
content of about 30 to about 60% by wt., in the presence of a Lewis
acid catalyst, such as aluminum trichloride or boron trifluoride,
with aluminium trichloride preferred. A preferred source of monomer
for making poly-n-butenes is petroleum feedstreams such as
Raffinate II. These feedstocks are disclosed in the art such as in
U.S. Pat. No. 4,952,739. Polyisobutylene is a most preferred
polymer of the present invention because it is readily available by
cationic polymerization from butene streams (e.g., using AlCl.sub.3
or BF.sub.3 catalysts). Such polyisobutylenes generally contain
residual unsaturation in amounts of about one ethylenic double bond
per polymer chain, positioned along the chain. A preferred
embodiment utilizes polyisobutylene prepared from a pure
isobutylene stream or a Raffinate I stream to prepare reactive
isobutylene polymers with terminal vinylidene olefins. Preferably,
these polymers, referred to as highly reactive polyisobutylene
(HR-PIB), have a terminal vinylidene content of at least 65%, e.g.,
70%, more preferably at least 80%, most preferably, at least 85%.
The preparation of such polymers is described, for example, in U.S.
Pat. No. 4,152,499. HR-PIB is known and HR-PIB is commercially
available under the tradenames Glissopal.TM. (from BASF) and
Ultravis.TM. (from BP-Amoco).
[0040] In another embodiment, the non-hydrogenated olefin
(co)polymer, for example, polyisobutylene, has at most 10, such as
5 to 10, %, of the polymer chains possessing a terminal double bond
(or terminal ethenylidene-type or terminal vinylidene
unsaturation). Such a polymer is considered not highly reactive, an
example of a commercially available polymer is under tradename
Napvis.TM. (from BP-Amoco), and usually obtained by polymerization
with aluminium trichloride as catalyst.
[0041] Preferably the (co)polymer is derived from polymerisation of
one or more olefins having 2 to 10, such as 3 to 8, carbon atoms.
An especially preferred olefin is butene, advantageously
isobutene.
[0042] The number average molecular weight of the non-hydrogenated
olefin (co)polymer useful in the present invention is preferably in
the range of from about 450 to about 2300, such as from about 450
to about 1300, preferably from about 450 to about 950. The
molecular weight can be determined by several known techniques. A
convenient method for such determination is by gel permeation
chromatography (GPC), which additionally provides molecular weight
distribution information (see W. W. Yau, J. J Kirkland and D. D
Bly, "Modern Size Exclusion Liquid Chromatography", John Wiley and
Sons, New York, 1979). Further, it is preferred that the kinematic
viscosity of the non-hydrogenated olefin polymer at 100.degree. C.
as measured according to ASTM D445, is at least 9 or 15, such as
100 or 150 to 3000, advantageously 200 to 2500 or 2700
mm.sup.2s.sup.-1. In one embodiment of the present invention, a
polyisobutylene polymer having a number average molecular weight of
450 to 2300, and a kinematic viscosity at 100.degree. C. of from
about 200 to 2400 mm.sup.2s.sup.-1 was found to provide
particularly beneficial properties. Lubricating oil compositions of
the present invention can contain the non-hydrogenated olefin
polymer in an amount of from about 0.2 to about 10.0 mass %, such
as from about 0.3 to about 5.0 mass %, particularly from about 0.5
to about 3.0 mass %, preferably from about 1.0 to about 2.5 mass
%.
[0043] Dispersants (or dispersant additives), such as ashless (i.e.
metal-free) dispersants hold solid and liquid contaminants,
resulting from oxidation during use, in suspension and thus
preventing sludge flocculation and precipitation or deposition on
metal parts; they comprise long-chain hydrocarbons, to confer
oil-solubility, with a polar head capable of associating with
particles to be dispersed. A noteworthy group is
hydrocarbon-substituted succinimides.
[0044] Generally, ashless dispersants form substantially no ash on
combustion, in contrast to metal-containing (and thus ash-forming)
detergents. Borated, metal-free dispersants are also regarded
herein as ashless dispersants. "Substantially no ash" means that
the dispersant may give trace amounts of ash on combustion, but
amounts which do not have practical or significant effect on the
performance of the dispersant. A dispersant additive composition
containing two or more dispersants may also be used.
[0045] Ashless, dispersants comprise an oil soluble polymeric long
chain backbone having functional groups capable of associating with
particles to be dispersed. Typically, such dispersants have amine,
amine-alcohol or amide polar moieties attached to the polymer
backbone, often via a bridging group. The ashless dispersant may
be, for example, selected from oil soluble salts, esters,
amino-esters, amides, imides and oxazolines of long chain
hydrocarbon-substituted mono- and polycarboxylic acids or
anhydrides thereof; thiocarboxylate derivatives of long chain
hydrocarbons; long chain aliphatic hydrocarbons having polyamine
moieties attached directly thereto; and Mannich condensation
products formed by condensing a long chain substituted phenol with
formaldehyde and polyalkylene polyamine. Suitable dispersants
include, for example, derivatives of long chain
hydrocarbyl-substituted carboxylic acids, in which the hydrocarbyl
group has a number average molecular weight tends of less than
15,000, such as less than 5,000; examples of such derivatives being
derivatives of high molecular weight hydrocarbyl-substituted
succinic acid. Such hydrocarbyl-substituted carboxylic acids may be
derivatized with, for example, a nitrogen-containing compound,
advantageously a polyalkylene polyamine or amine-alcohol or amide
or ester. Particularly preferred dispersants are the reaction
products of polyalkylene amines with alkenyl succinic anhydrides.
Examples of specifications disclosing dispersants of the
last-mentioned type are U.S. Pat. Nos. 3,202,678; 3,154,560;
3,172,892; 3,024,195; 3,024,237; 3,219,666; 3,216,936; and BE-A-662
875.
[0046] The dispersant(s) are preferably non-polymeric (e.g., are
mono- or bis-succinimides). The dispersant(s) of the present
invention may optionally be borated. Such dispersants can be
borated by conventional means, as generally taught in U.S. Pat.
Nos. 3,087,936, 3,254,025 and 5,430,105. Boration of the dispersant
is readily accomplished by treating an acyl nitrogen-containing
dispersant with a boron compound such as boron oxide, boron halide
boron acids, and esters of boron acids, in an amount sufficient to
provide from about 0.1 to about 20 atomic proportions of boron for
each mole of acylated nitrogen composition. Combinations of borated
and non-borated dispersants may also be employed.
[0047] An ashless succinimide or a derivative thereof, obtainable
from a polyisobutenylsuccinic anhydride produced from polybutene
and maleic anhydride by a thermal reaction method using neither
chlorine nor a chlorine atom-containing compound, is a preferred
dispersant.
[0048] Dispersancy may be provided by polymeric compounds capable
of providing viscosity index improving properties and dispersancy,
such compounds are known as a dispersant viscosity index improver
additive or a multifunctional viscosity index improver. Such
polymers differ from conventional viscosity index improvers in that
they provide performance properties, such as dispersancy and/or
antioxidancy, in addition to viscosity index improvement (see below
under viscosity modifiers for further detail on multifunctional
viscosity modifiers). In the event, a dispersant viscosity index
improver additive is used in the lubricating oil compositions of
the present invention, a dispersant additive is, preferably, also
present.
[0049] Typically, one or more dispersants and/or dispersant
viscosity index improvers, are used in heavy duty diesel (HDD)
engine lubricating oil composition in amounts that provide the
lubricating oil composition with a nitrogen content of from about
0.08 mass % to about 0.35 mass %, such as from about 0.09 mass % to
about 0.25 mass %, preferably from about 0.10 mass % to about 0.20
mass %. In a passenger car diesel engine lubricating oil
composition (PCDO), dispersant is generally added in amounts that
provide the lubricating oil composition with a nitrogen content of
from about 0.04 mass % to about 0.10 mass %, such as from about
0.05 mass % to about 0.09 mass %, preferably from about 0.065 mass
% to about 0.085 mass %. In a passenger car motor oil for a
spark-ignited engine (PCMO), dispersant is generally added in
amounts that provide the lubricating oil composition with a
nitrogen of from about 0.02 mass % to about 0.12 mass %, such as
from about 0.03 mass % to about 0.08 mass %, preferably from about
0.035 mass % to about 0.05 mass %. In manual transmission fluids
(MTF), dispersant is generally added in amounts that provide the
lubricating oil composition with a nitrogen content of from about
0.02 mass % to about 0.08 mass %, such as from about 0.025 mass %
to about 0.06 mass %, preferably from about 0.03 mass % to about
0.05 mass %. In an automatic transmission fluid (ATF), dispersant
is generally added in an amount providing the lubricating oil
composition with a nitrogen content of from about 0.02 mass % to
about 0.14 mass %, such as from about 0.05 mass % to about 0.11
mass %, preferably from about 0.06 mass % to about 0.08 mass %.
[0050] A detergent (or detergent additive) reduces formation of
piston deposits, for example high-temperature varnish and lacquer
deposits, by keeping finely divided solids in suspension in
engines; it may also have acid-neutralizing properties. A detergent
comprises metal salts of organic acids, which are referred herein
as soaps or surfactants. A detergent has a polar head, i.e. the
metal salt of the organic acid, with a long hydrophobic tail for
oil solubility. Therefore, the organic acids typically have one or
more functional groups, such as OH or COOH or SO.sub.3H, for
reacting with a metal, and a hydrocarbyl substituent. A detergent
may be overbased, in which case the detergent contains an excess of
metal in relation to the stoichiometric quantity needed for the
neutralization of the organic acid. This excess is in the form of a
colloidal dispersion, typically metal carbonate and/or hydroxide,
with the metal salts of organic acids in a micellar structure.
[0051] Examples of organic acids include sulfonic acids, phenols
and sulfurized derivatives thereof, and carboxylic acids including
aromatic carboxylic acids.
[0052] Phenols may be non-sulfurized or sulfurized. Further, the
term "phenol" as used herein includes phenols containing more than
one hydroxyl group (for example, alkyl catechols) or fused aromatic
rings (for example, alkyl naphthols) and phenols which have been
modified by chemical reaction, for example, alkylene-bridged
phenols and Mannich base-condensed phenols; and saligenin-type
phenols (produced by the reaction of a phenol and an aldehyde under
basic conditions). The phenols are frequently used in sulfurized
form. Details of sulfurization processes are known to those skilled
in the art, for example, see U.S. Pat. Nos.4,228,022 and
4,309,293.
[0053] As indicated above, the term "phenol" as used herein
includes phenols which have been modified by chemical reaction
with, for example, an aldehyde, and Mannich base-condensed phenols.
Aldehydes with which phenols may be modified include, for example,
formaldehyde, propionaldehyde and butyraldehyde. The preferred
aldehyde is formaldehyde. Aldehyde-modified phenols suitable for
use in accordance with, the present invention are described in, for
example, U.S. Pat. Nos. 5,259,967 and 6,310,009. Mannich
base-condensed phenols are prepared by the reaction of a phenol, an
aldehyde and an amine. Examples of suitable Mannich base-condensed
phenols are described in U.S. Pat. Nos. 4,708,809 and 4,740,321. In
general, the phenols may include substituents other than those
mentioned above. Examples of such substituents are methoxy groups
and halogen atoms.
[0054] Sulfonic acids are typically obtained by sulfonation of
hydrocarbyl-substituted, especially alkyl-substituted, aromatic
hydrocarbons, for example, those obtained from the fractionation of
petroleum by distillation and/or extraction, or by the alkylation
of aromatic hydrocarbons. The alkylaryl sulfonic acids usually
contain from about 22 to about 100 or more carbon atoms. The
sulfonic acids may be substituted by more than one alkyl group on
the aromatic moiety, for example they may be dialkylaryl sulfonic
acids. Preferably the sulfonic acid has a number average molecular
weight of 350 or greater, more preferably 400 or greater,
especially 500 or greater, such as 600 or greater. Number average
molecular weight may be determined by ASTM D3712. Another type of
sulfonic acid which may be used in accordance with the invention
comprises alkyl phenol sulfonic acids. Such sulfonic acids can be
sulfurized.
[0055] Carboxylic acids include mono and dicarboxylic acids.
Preferred monocarboxylic acids are those containing 8 to 30,
especially 8 to 24, carbon atoms. (Where this specification
indicates the number of carbon atoms in a carboxylic acid, the
carbon atom(s) in the carboxylic group(s) is/are included in that
number). Examples of monocarboxylic acids are iso-octanoic acid,
stearic acid, oleic acid, palmitic acid and behenic acid.
Iso-octanoic acid may, if desired, be used in the form of the
mixture of C8 acid isomers sold by Exxon Chemical under the trade
name "Cekanoic". Other suitable acids are those with tertiary
substitution at the .alpha.-carbon atom and dicarboxylic acids with
2 or more carbon atoms separating the carboxylic groups. Further,
dicarboxylic acids with more than 35 carbon atoms, for example, 36
to 100 carbon atoms, are also suitable. Unsaturated carboxylic
acids can be sulfurized.
[0056] A preferred type of carboxylic acid is an aromatic
carboxylic acid. The aromatic moiety of the aromatic carboxylic
acid can contain hetero atoms, such as nitrogen and oxygen.
Preferably, the moiety contains only carbon atoms; more preferably
the moiety contains six or more carbon atoms; for example benzene
is a preferred moiety. The aromatic carboxylic acid may contain one
or more aromatic moieties, such as one or more benzene rings,
either fused or connected via alkylene bridges.
[0057] The carboxylic moiety may be attached directly or indirectly
to the aromatic moiety. Preferably the carboxylic acid group is
attached directly to a carbon atom on the aromatic moiety, such as
a carbon atom on the benzene ring. The aromatic moiety may also
contain a second functional group, such as a hydroxyl group or a
sulfonate group, which can be attached directly or indirectly to a
carbon atom on the aromatic moiety. Preferred examples of aromatic
carboxylic acids are salicylic acids and sulfurized derivatives
thereof, such as hydrocarbyl substituted salicylic acid and
derivatives thereof. Processes for sulfurizing, for example a
hydrocarbyl-substituted salicylic acid, are known to those skilled
in the art.
[0058] Salicylic acids are typically prepared by carboxylation, for
example, by the Kolbe-Schmitt process, of phenoxides, and in that
case, will generally be obtained, normally in a diluent, in
admixture with uncarboxylated phenol.
[0059] Preferred substituents for oil-soluble salicylic acids are
alkyl substituents. In alkyl-substituted salicylic acids, the alkyl
groups advantageously contain 5 to 100, preferably 9 to 30,
especially 14 to 20, carbon atoms. Where there is more than one
alkyl group, the average number of carbon atoms in all of the alkyl
groups is preferably at least 9 to ensure adequate
oil-solubility.
[0060] The metal detergent may be neutral or overbased, such terms
are known in the art. A detergent additive composition may comprise
one or more detergent additives, which can be a neutral detergent,
an overbased detergent or a mixture of both. The Total Base Number
(TBN) of detergents will conventionally range from 15 to 600.
[0061] Detergents generally useful in the formulation of
lubricating oil compositions also include "hybrid" detergents
formed with mixed surfactant systems, e.g., phenate/salicylates
(sometimes referred to as "phenalates"), sulfonate/phenates,
sulfonate/salicylates, sulfonates/phenates/salicylates, as
described, for example, in U.S. Pat. Nos. 6,153,565; 6,281,179;
6,429,178; and 6,429,179.
[0062] A detergent additive composition may contain two or more
detergents, for example, an alkali metal, such as sodium,
detergent, and an alkaline earth metal, such as calcium and/or
magnesium, detergent. The detergent additive composition may also
comprise an ashless detergent, i.e. a non-metal containing
detergent, typically in the form of an organic salt of an organic
acid. The detergents are preferably metal containing and Group 1
and Group 2 metals are preferred as metals in the detergents, more
preferably calcium and magnesium, especially calcium.
[0063] Typically, one or more detergents are used in heavy duty
diesel (HDD) engine lubricating oil composition in amounts that
provide the lubricating oil composition with a TBN of from about
4.0 to about 11.5, such as from about 6.0 to about 9.5, preferably
from about 7.0 to about 8.25. In a passenger car diesel engine
lubricating oil composition (PCDO), detergent is generally added in
amounts that provide the lubricating oil composition with a TBN of
from about 5.0 to about 12.0, such as from about 6.0 to about 11.0,
preferably from about 7.0 to about 10.5. In a passenger car motor
oil for a spark-ignited engine (PCMO), detergent(s) is generally
added in amounts that provide the lubricating oil composition with
a TBN of from about 2.5 to about 9.9, such as from about 4.0 to
about 8.0, preferably from about 4.5 to about 7.25. In a power
transmission fluid (PTF), detergent(s) is generally added in
amounts that provide the lubricating oil composition with a TBN of
from about 0.0 to about 10.0, such as from about 0.5 to about 5.0,
preferably from about 1.0 to about 2.5. Where the detergent is a
sulfonate detergent, a sulfurized phenate detergent, or a hybrid
detergent containing a sulfurized phenate and/or sulfonate
component, the use of a conventional amount of such detergents can
introduce into the lubricating oil composition as much as 0.04 mass
%, even as much as 0.15 mass %, such as from about 0.06 to about
0.12 mass % of sulfur.
[0064] In one embodiment, the invention is directed specifically to
lubricating oil compositions containing salicylate detergent in an
amount introducing at least about 9 mmols (e.g, about 12 to about
50 mmols), such as at least about 18 mmols (e.g. about 18 to about
33 mmols) particularly at least about 24 mmols of salicylate soap
per kilogram of finished lubricant and from about 1.0 mass % to
about 2.5 mass % of the non-hydrogenated polymer described
supra.
[0065] In another embodiment, the invention is directed
specifically to low ash compositions having an ash (reported as
sulfated ash or SASH) content of less than 1.1 mass %, such as less
than 1.05 mass%, preferably less than 0.8 mass %; and a sulfur
content of from about 0.10 mass % to about 0.40 mass %, such as
from about 0.15 mass % to about 0.35 mass %, preferably from about
0.20 mass % to about 0.30 mass % of sulfur, which compositions
contain salicylate detergent in an amount introducing at least
about 9 mmols, such as at least about 18 mmols, preferably at least
about 24 mmols, of salicylate soap per kilogram of finished
lubricant and from about 1.0 mass % to about 2.5 mass % of the
non-hydrogenated polymer described supra.
[0066] Anti-wear agents reduce friction and excessive wear and are
usually based on compounds containing sulfur or phosphorus or both.
Dihydrocarbyl dithiophosphate metal salts are frequently used as
anti-wear and antioxidant agents. The metal may be an alkali or
alkaline earth metal, or aluminum, lead, tin, molybdenum,
manganese, nickel or copper. The zinc salts (ZDDP) are most
commonly used in lubricating oil in amounts of 0.1 to 10,
preferably 0.2 to 2 mass %, based upon the total weight of the
lubricating oil composition. They may 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 having 1 to 18, preferably 2 to 12, carbon atoms.
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 generally employed. Commercial additives
frequently contain an excess of zinc due to use of an excess of the
basic zinc compound in the neutralization reaction.
[0067] ZDDP provides excellent wear protection at a comparatively
low cost and also functions as an antioxidant. Preferably a zinc
dialkyl dithiophosphate composition comprising one or more zinc
dialkyl dithiophosphate, which composition especially contains a
mixture of primary and secondary alkyl groups, wherein the
secondary alkyl groups are in a major molar proportion, such as at
least 60, advantageously at least 75, more especially at least 85,
mole %, based on the amount of alkyl groups, is useful in the
present invention. Preferably a zinc dithiophosphate composition
has 90 mole % secondary alkyl groups and 10 mole % primary alkyl
groups.
[0068] When used in conventional amounts, sulfur-containing
antiwear agents can introduce into the lubricating oil composition
as much as 0.15 mass %, and even as much as 0.30 mass %, such as
from about 0.16 to about 0.25 mass % of sulfur.
[0069] Anti-oxidants increase the composition's resistance to
oxidation and may work by combining with and modifying peroxides to
render them harmless by decomposing peroxides or by rendering an
oxidation catalyst inert. They may be classified as radical
scavengers (e.g. sterically hindered phenols, secondary aromatic
amines, and organo-copper salts); hydroperoxide decomposers (e.g.
organo-sulfur and organophosphorus additives); and
multifunctionals. Such anti-oxidants (or oxidation inhibitors)
include hindered phenols, aromatic amine compounds, alkaline earth
metal and metal-free alkylphenolthioesters having preferably
C.sub.5 to C.sub.12 alkyl side chains, ashless alkylene bridged
phenols, phosphosulfurized and sulftrized hydrocarbons, phosphorous
esters, metal and metal-free thiocarbamates & derivatives
thereof, oil soluble copper compound as described in U.S. Pat. No.
4,867,890, and molybdenum containing compounds. In the practice of
the present invention, the use or otherwise of certain
anti-oxidants may confer certain benefits. For example, in one
embodiment it is preferred that an anti-oxidant composition
comprising a hindered phenol with an ester group is used. In
another embodiment, it is preferred to employ an anti-oxidant
composition comprising a secondary aromatic amine and said hindered
phenol. Preferably an antioxidant composition comprising an
aromatic amine, such as diphenylamine and/or a hindered phenol
compound, such as 3,5-bis(alkyl)4-hydroxyphenyl carboxylic acid
esters, e.g. IRGANOX.RTM. L135 as sold by Ciba Specialty Chemicals,
is useful.
[0070] Friction modifiers include boundary additives that lower
friction coefficients and hence improve fuel economy. Examples are
esters of polyhydric alcohols such as glycerol monoesters of higher
fatty acids, for example glycerol mono-oleate; esters of long chain
polycarboxylic acids with diols, for example the butane diol esters
of dimerized unsaturated fatty acids; oxazoline compounds; and
alkoxylated alkyl-substituted mono-amines, and alkyl ether amines,
for example, ethoxylated tallow amine and ethoxylated tallow ether
amine. Molybdenum-containing compounds and ashless dithiocarbamates
are also examples of known friction modifiers. Conventionally, one
or more organic friction modifiers are used in an amount of 0.1 to
0.5, such as 0.2 to 0.4, mass %, based on the mass of the oil
composition.
[0071] The molybdenum-containing compounds, preferably
molybdenum-sulfur compounds, useful in the present invention may be
mononuclear or polynuclear. In the event that the compound is
polynuclear, the compound contains a molybdenum core consisting of
non-metallic atoms, such as sulfur, oxygen and selenium, preferably
consisting essentially of sulfur.
[0072] To enable the molybdenum-sulfur compound to be oil-soluble
or oil-dispersible, one or more ligands are bonded to a molybdenum
atom in the compound. The bonding of the ligands includes bonding
by electrostatic interaction as in the case of a counter-ion and
forms of bonding intermediate between covalent and electrostatic
bonding. Ligands within the same compound may be differently
bonded. For example, a ligand may be covalently bonded and another
ligand may be electrostatically bonded.
[0073] Preferably, the or each ligand is monoanionic and examples
of such ligands are dithiophosphates, dithiocarbamates, xanthates,
carboxylates, thioxanthates, phosphates and hydrocarbyl, preferably
alkyl, derivatives thereof. Preferably, the ratio of the number of
molybdenum atoms, for example, in the core in the event that the
molybdenum-sulfur compound is a polynuclear compound, to the number
of monoanionic ligands, capable of rendering the compound
oil-soluble or oil-dispersible, is greater than 1 to 1, such as at
least 3 to 2.
[0074] The molybdenum-sulfur compound's oil-solubility or
oil-dispersibility may be influenced by the total number of carbon
atoms present among all of the compound's ligands. The total number
of carbon atoms present among all of the hydrocarbyl groups of the
compound's ligands typically will be at least 21, e.g., 21 to 800,
such as at least 25, at least 30 or at least 35. For example, the
number of carbon atoms in each alkyl group will generally range
between 1 and 100, preferably 1 and 40, and more preferably between
3 and 20. Examples of molybdenum-sulfur compounds include dinuclear
molybdenum-sulfur compounds and trinuclear molybdenum-sulfur
compounds.
[0075] An example of a dinuclear molybdenum-sulfur compound is
represented by the formula: ##STR1## where R.sub.1 to R.sub.4
independently denote a straight chain, branched chain or aromatic
hydrocarbyl group having 1 to 24 carbon atoms; and X.sub.1 to
X.sub.4 independently denote an oxygen atom or a sulfur atom. The
four hydrocarbyl groups, R.sub.1 to R.sub.4, may be identical or
different from one another.
[0076] In a preferred embodiment, the molybdenum-sulfur compound is
an oil-soluble or oil-dispersible trinuclear molybdenum-sulfur
compound. Examples of trinuclear molybdenum-sulfur compounds are
disclosed in U.S. Pat. Nos. 5,888,945; 5,906,968; 6,010,987;
6,110,878; 6,153,564; 6,232,276; 6,358,894; 6,541,429; 6,569,820;
and European patent application no. 02078011, each of which are
incorporated into the present description by reference,
particularly with respect to the characteristics of the molybdenum
compound or additive disclosed therein.
[0077] Preferably, the trinuclear molybdenum-sulfur compounds are
represented by the formula
Mo.sub.3S.sub.kE.sub.xL.sub.nA.sub.pQ.sub.z, wherein k is an
integer of at least 1; E represents a non-metallic atom selected
from oxygen and selenium; x can be 0 or an integer, and preferably
k+x is at least 4, more preferably in the range of 4 to 10, such as
4 to 7, most preferably 4 or 7; L represents a ligand that confers
oil-solubility or oil-dispersibility on the molybdenum-sulfur
compound, preferably L is a monoanionic ligand; n is an integer in
the range of 1 to 4; A represents an anion other than L, if L is an
anionic ligand; p can be 0 or an integer; Q represents a neutral
electron-donating compound; and z is in the range of 0 to 5 and
includes non-stoichiometric values.
[0078] Those skilled in the art will realize that formation of the
trinuclear molybdenum-sulfur compound will require selection of
appropriate ligands (L) and other anions (A), depending on, for
example, the number of sulfur and E atoms present in the core, i.e.
the total anionic charge contributed by sulfur atom(s), E atom(s),
if present, L and A, if present, must be -12. The trinuclear
molybdenum-sulfur compound may also have a cation other than
molybdenum, for example, (alkyl)ammonium, amine or sodium, if the
anionic charge exceeds -12.
[0079] Examples of Q include water, alcohol, amine, ether and
phosphine. It is believed that the electron-donating compound, Q,
is merely present to fill any vacant coordination sites on the
trinuclear molybdenum-sulfur compound. Examples of A can be of any
valence, for example, monovalent and divalent and include
disulfide, hydroxide, alkoxide, amide and thiocyanate or derivative
thereof; preferably A represents a disulfide ion. Preferably, L is
monoanionic ligand, such as dithiophosphates, dithiocarbamates,
xanthates, carboxylates, thioxanthates, phosphates and hydrocarbyl,
preferably alkyl, derivatives thereof. When n is 2 or more, the
ligands can be the same or different. In an embodiment,
independently of the other embodiments, k is 4 or 7, n is either 1
or 2, L is a monoanionic ligand, p is an integer to confer
electrical neutrality on the compound based on the anionic charge
on A and each of x and z is 0. In a further embodiment,
independently of the other embodiments, k is 4 or 7, L is a
monoanionic ligand, n is 4 and each of p, x and z is 0. Other
examples of molybdenum containing compounds include molybdenum
carboxylates and molybdenum nitrogen complexes, both of which may
be sulfurised.
[0080] Where a sulfur-containing molybdenum compound is employed as
a friction modifier and/or antioxidant, and used in a conventional
amount such as an amount providing from about 20 ppm to about 250
ppm, such as from about 50 ppm to about 125ppm of Mo, such
compounds can introduce into the lubricating oil composition about
0.004 mass % or more, or about 0.008 mass % or more, such as from
about 0.004 mass % to about 0.090 mass %, e.g., from about 0.008 to
about 0.025 mass % of sulfur.
[0081] Boron may also be present in the lubricating oil
compositions of the present invention. Boron-containing additives
may be prepared by reacting a boron compound with an oil-soluble or
oil-dispersible additive or compound. Boron compounds include boron
oxide, boron oxide hydrate, boron trioxide, boron trifluoride,
boron tribromide, boron trichloride, boron acid such as boronic
acid, boric acid, tetraboric acid and metaboric acid, boron
hydrides, boron amides and various esters of boron acids. Examples
of boron-containing additives include a borated dispersant; a
borated dispersant VI improver; an alkali metal or a mixed alkali
metal or an alkaline earth metal borate; a borated overbased metal
detergent; a borated epoxide; a borate ester; a sulfurized borate
ester; and a borate amide. A preferred boron-containing additive is
a borated dispersant.
[0082] Examples of other additives include rust inhibitors,
corrosion inhibitors, pour point depressants, anti-foaming agents
and viscosity modifiers.
[0083] Rust inhibitors selected from the group consisting of
nonionic polyoxyalkylene polyols and esters thereof,
polyoxyalkylene phenols, and anionic alkyl sulfonic acids may be
used.
[0084] Copper and lead bearing corrosion inhibitors may be used,
but are typically not required with the formulation of the present
invention. Typically such compounds are the thiadiazole
polysulfides containing from 5 to 50 carbon atoms, their
derivatives and polymers thereof. Derivatives of
1,3,4-thiadiazoles, such as those described in U.S. Pat. Nos.
2,719,125; 2,719,126; and 3,087,932; are typical. Other similar
materials are described in U.S. Pat. Nos. 3,821,236; 3,904,537;
4,097,387; 4,107,059; 4,136,043; 4,188,299; and 4,193,882. Other
additives are the thio and polythio sulfenamides of thiadiazoles
such as those described in U.K. Patent Specification No. 1,560,830.
Benzotriazoles derivatives also fall within this class of
additives. When these compounds are included in the lubricating
composition, they are preferably present in an amount not exceeding
0.2 mass % (A.I.).
[0085] A small amount of a demulsifying component may be used. A
preferred demulsifying component is described in EP 330,522. It is
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 % A.I. A treat
rate of 0.001 to 0.05 mass % (A.I.) is convenient.
[0086] Pour point depressants, otherwise known as lube oil
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 and C.sub.18 dialkyl fumarate/vinyl acetate
copolymers, polyalkylmethacrylates and the like.
[0087] Foam control can be provided by many compounds including an
antifoamant of the polysiloxane type, for example, silicone oil or
polydimethyl siloxane.
[0088] Viscosity index improvers (or viscosity modifiers) impart
high and low temperature operability to a lubricating oil and
permit it to remain shear stable at elevated temperatures and also
exhibit acceptable viscosity or fluidity at low temperatures.
Suitable compounds for use as viscosity modifiers are generally
high molecular weight hydrocarbon polymers, e.g. polyisobutylene,
copolymers of ethylene and propylene and higher alpha-olefins;
polyesters, such as polymethacrylates; hydrogenated
poly(styrene-co-butadiene or -isoprene) polymers and modifications
(e.g., star polymers); and esterified poly(styrene-co-maleic
anhydride) polymers . Oil-soluble viscosity modifying polymers
generally have number average molecular weights of at least 15,000
to 1,000,000, preferably 20,000 to 600,000, as determined by gel
permeation chromatography or light scattering methods. The
disclosure in Chapter 5 of "Chemistry & Technology of
Lubricants", edited by R. M. Mortier and S. T. Orzulik, First
edition, 1992. Blackie Academic & Professional, is incorporated
herein. The VM used may have that sole function, or may be
multifunctional, such as demonstrating viscosity index improving
properties as well as dispersant properties. Dispersant olefin
copolymers and dispersant polymethacrylates are examples of
dispersant viscosity index improver additives. Dispersant viscosity
index improver additives are prepared by chemically attaching
various functional moieties, for example amines, alcohols and
amides, onto polymers, which polymers preferably tend to have a
number average molecular weight of at least 15,000, such in the
range from 20,000 to 600,000, as determined by gel permeation
chromatography or light scattering methods. The polymers used may
be those described below with respect to viscosity modifiers.
Therefore, amine molecules may be incorporated to impart
dispersancy and/or antioxidancy characteristics, whereas phenolic
molecules may be incorporated to improve antioxidant properties. A
specific example, therefore, is an inter-polymer of
ethylene-propylene post grafted with an active monomer such as
maleic anhydride and then derivatized with, for example, an alcohol
or amine. In the event a dispersant viscosity modifier is used in
the present invention, the nitrogen content of the lubricating oil
composition also includes that derived from the dispersant
viscosity modifier. An example of a dispersant viscosity modifier
is Hitec.RTM. 5777, which is manufactured and sold by Afton Corp.
U.S. Pat. Nos.4,867,890 and 5,958,848 describe examples of
dispersant viscosity index improvers, which are accordingly
incorporated herein. Generally, viscosity modifiers, whether
multifunctional or not, are used in an amount depending on the
desired viscometric grade (e.g., SAE 10W-40) of the lubricating oil
composition, for example, an amount of 0.001 to 2, preferably 0.01
to 1.5, such as 0.1 to 1, mass % of the polymer, based on the mass
of the oil composition.
[0089] Representative effective amounts of such additives, when
used in lubricating oil compositions, are as follows:
TABLE-US-00002 Mass % a.i.* Mass % a.i.* Additive (Broad)
(Preferred) Viscosity Modifier 0.01-6 0.01-4 Corrosion Inhibitor
0.0-5 0.01-1.5 Oxidation Inhibitor 0.01-5 0.01-3 Friction Reducer
0.01-5 0.01-1.5 Dispersant 0.1-20 0.1-8 Multifunctional Viscosity
Modifier 0.0-5 0.05-5 Detergent 0.01-6 0.01-4 Anti-wear Agent
0.01-6 0.01-4 Pour Point Depressant 0.01-5 0.01-1.5 Rust Inhibitor
0.0-0.5 0.001-0.2 Anti-Foaming Agent 0.001-0.3 0.001-0.15
Demulsifier 0.0-0.5 0.001-0.2 *mass % active ingredient based on
the final lubricating oil composition.
[0090] An additive concentrate constitutes a convenient means of
handling two or more additives before their use, as well as
facilitating solution or dispersion of the additives in lubricant
compositions. When preparing a lubricant composition that contains
more than one type of additive (sometimes referred to as "additive
components"), each additive may be incorporated separately. In many
instances, however, it is convenient to incorporate the additives
as an additive concentrate (a so-called additive "package" (also
referred to as an "adpack")) comprising two or more additives).
[0091] In the preparation of the lubricant oil compositions, it is
common practice to introduce additives in the form of additive
concentrate(s) containing the additives. When a plurality of
additives are employed it may be desirable, although not essential,
to prepare one or more additive concentrates (also known as
additive packages) comprising the additives, whereby several
additives, with the exception of viscosity modifiers,
multifunctional viscosity modifiers and pour point depressants, can
be added simultaneously to the oil of lubricating viscosity to form
the lubricating oil composition. Dissolution of the additive
concentrate(s) into the lubricating oil may be facilitated by
diluent or solvents and by mixing accompanied with mild heating,
but this is not essential. The additive concentrate(s) will
typically be formulated to contain the additive(s) in proper
amounts to provide the desired concentration in the final
formulation when the additive concentrate(s) is/are combined with a
predetermined amount of oil of lubricating viscosity. If required,
the viscosity modifiers, or multifunctional viscosity modifiers,
and pour point depressants are then separately added to form a
lubricating oil composition.
[0092] An additive concentrate may contain 1 to 90, such as 10 to
80, preferably 20 to 80, more preferably 40 to 70, mass % based on
active ingredient, of the additives, the remainder being an
oleaginous carrier or diluent fluid (for example, an oil of
lubricating viscosity). The final lubricating oil composition may
typically contain 5 to 40 mass % of the additive
concentrate(s).
[0093] The amount of additives in the final lubricating oil
composition is generally dependent on the type of the oil
composition, for example, a heavy duty diesel engine lubricating
oil composition preferably has 7 to 25, more preferably 8 to 23,
such as 8 to 20, mass % of additives (including any diluent fluid),
based on the mass of the oil composition. A passenger car engine
lubricating oil composition, for example, a gasoline or a diesel
engine oil composition, tends to have a lower amount of additives,
for example 2 to 16, such as 3 or 4 to 14, preferably 5 to 12,
especially 6 to 10, mass % of additives, based on the mass of the
oil composition. The amounts expressed above exclude
non-hydrogenated olefin polymer, viscosity modifier and pour point
depressant additives.
[0094] Generally the viscosity of the additive concentrate is
higher than that of the lubricating oil composition. Typically, the
kinematic viscosity at 100.degree. C. of the additive concentrate
is at least 50, such as in the range 100 to 200, preferably 120 to
180, mm.sup.2s.sup.-1 (or cSt).
[0095] Thus, a method of preparing a lubricating oil composition
according to the present invention can involve admixing an oil of
lubricating viscosity and one or more of additives or additive
concentrates that comprises two or more of additives and then,
admixing other additive components, such as viscosity modifier, and
optionally a multifunctional viscosity modifier and pour point
depressant.
[0096] Lubricating oil compositions of the present invention may
also be prepared by admixing an oil of lubricating viscosity, an
additive concentrate containing two or more additive components, a
non-hydrogenated olefin polymer and a viscosity modifier, and
optionally a multifunctional viscosity modifier and pour point
depressant.
[0097] It is preferred that lubricating oil compositions of the
invention are multigrade oil compositions having a viscometric
grade of SAE 10W-X, SAE 5W-X and SAE 0W-X, where X represents 20,
30 and 40; the characteristics of the different grades can be found
in the SAE J300 classification.
[0098] Fully formulated lubricating oil compositions of the present
invention preferably have a sulfur content of from about 0.15 mass
% to about 1.0 mass %, such as from about 0.20 mass % to about 0.35
mass %. Preferably, the Noack volatility of the fully formulated
lubricating oil composition (oil of lubricating viscosity plus all
additives) will be no greater than 13, such as no greater than 12,
preferably no greater than 10. Fully formulated lubricating oil
compositions of the present invention preferably have a phosphorus
content of less than about 1500 ppm, such as from about 500 to 1500
ppm, preferably less than 1250 ppm, such as from about 500 to about
1250 ppm, more preferably less than about 1200 ppm, such as from
about 500 to about 1200 ppm, still more preferably less than about
850 ppm, such as from about 500 to 850 ppm, based on the total mass
of the lubricating oil composition.
[0099] Fully formulated lubricating oil compositions of the present
invention preferably have a sulfated ash (SASH) content of about
1.9 mass % or less, preferably about 1.1 mass % or less, such as
about 1.05 mass % or less.
[0100] The amount of phosphorus and sulfur are determined according
to method ASTM D5185; "TBN" is Total Base Number as measured by
ASTM D2896; the amount of nitrogen is determined according to
method ASTM D4629; and sulfated ash is measured according to method
ASTM D874.
[0101] Where the lubricating oil compositions of the present
invention are for HDD use, the lubricating oil compositions
preferably satisfy at least the performance requirements of the
ACEA E2-96#5, more preferably at least the ACEA E7-04 and/or API
CI-4, such as at least the ACEA E4-99#3, especially at least the
ACEA E6-04 and/or API CJ-4 specification. Where the lubricating oil
compositions of the present invention are for PCDO use, the
lubricating oil compositions preferably satisfy at least the
performance requirements of the ACEA B2-98#2, more preferably at
least the ACEA B3-04, such as at least the ACEA B4-04/ ACEA C3-04,
especially at least the ACEA B5-04/ ACEA C3-04/ ACEA C2-04
specification(s). Where the lubricating oil compositions of the
present invention are for PCMO use, the lubricating oil
compositions preferably satisfy at least the performance
requirements of the ACEA A2-96#3/ API SJ, more preferably at least
the ACEA A3-04/ ACEA C3-04, such as at least the API SL/ ILSAC
GF-3, especially at least the ACEA A5-04/ ACEA C2-04/ ACEA C3-04/
API SM/ ILSAC GF4 specification(s).
[0102] It should be appreciated that interaction may take place
between any two or more of the additives, including any two or more
detergents, after they have been incorporated into the oil
composition. The interaction may take place in either the process
of mixing or any subsequent condition to which the composition is
exposed, including the use of the composition in its working
environment. Interactions may also take place when further
auxiliary additives are added to the compositions of the invention
or with components of oil. Such interaction may include interaction
which alters the chemical constitution of the additives. Thus, the
compositions of the invention include compositions in which
interaction, for example, between any of the additives, has
occurred, as well as compositions in which no interaction has
occurred, for example, between the components mixed in the oil.
[0103] The lubricating oil compositions may be used to lubricate
mechanical engine components, particularly an internal combustion,
such as a compression-ignited (diesel) engine, or a spark-ignited
(gasoline) engine or a manual or automatic transmission unit, by
adding the lubricating oil thereto and operating the
engine/transmission.
[0104] In this specification the term "hydrocarbyl" as used herein
means that the group concerned is primarily composed of hydrogen
and carbon atoms and is bonded to the remainder of the molecule via
a carbon atom, but does not exclude the presence of other atoms or
groups in a proportion insufficient to detract from the
substantially hydrocarbon characteristics of the group. The term
"comprising" or "comprises" when used herein is taken to specify
the presence of stated features, integers, steps or components, but
does not preclude the presence or addition of one or more other
features, integers, steps, components or groups thereof. In the
instance the term "comprising" or comprises" is used herein, the
term "consisting essentially of" and its cognates are a preferred
embodiment, while the term "consisting of" and its cognates are a
preferred embodiment of the term "consisting essentially of". The
term "oil-soluble" or "oil-dispersible", as used herein, does not
mean that the additives are soluble, dissolvable, miscible or
capable of being suspended in the oil in all proportions. They do
mean, however, that the additives are, for instance, soluble or
stable dispersible in the oil to an extent sufficient to exert
their intended effect in the environment in which the oil
composition is employed. Moreover, the additional incorporation of
other additives such as those described above may affect the
solubility or dispersibility of the additives. "Major amount" means
in excess of 50, such as greater than 70, preferably 75 to 97,
especially 80 to 95 or 90, mass %, of the composition. "Minor
amount" means less than 50, such as less than 30, for example, 3 to
25, preferably 5 or 10 to 20, mass %, of the composition mass % of
the composition. All percentages reported are mass % on an active
ingredient basis, i.e. without regard to carrier or diluent oil,
unless otherwise stated. The abbreviation SAE stands for Society of
Automotive Engineers, an organization that classifies lubricants by
viscosity grades.
EXAMPLES
[0105] The invention will now be particularly described, by way of
example only, as follows:
[0106] Example 1
[0107] A lubricating oil composition representing a conventional
10W40 crankcase lubricant for a heavy duty diesel engine meeting
the requirements of the ACEA E4-99#3 specification was prepared by
blending a base stock oil of lubricating viscosity, a
detergent/inhibitor (DI) package including salicylate detergent,
dispersant, ZDDP and antifoamant; a viscosity modifier (VM) and
lubricating oil flow improver (LOFI). The resulting composition had
a nitrogen content of 0.1 mass %; a sulfur content of 0.3 mass %, a
sulfated ash (SASH) content of 1.9 mass %, 1250 ppm of phosphorus
and 43 mmols of salicylate soap per kilogram of finished
lubricant.
[0108] Four lubricating oil compositions were prepared based on the
above recipe. Example 1, a comparative example, contained no added
450 M.sub.n, polybutene (PIB). Examples 2, 3 and 4, which represent
the invention, contained 0.5, 1 and 2 mass % of 450 M.sub.n PIB,
respectively. The four samples were then tested for compatibility
with nitrile rubber using the bench tests 5 used by Mercedes Benz
(MB) or Daimler Chrysler (DC), specifically Test Method VDA6753014;
Maschinenfabrik Augsburg & Nurnberg (MAN), specifically Test
Method DIN53521 (nitrile seal); and Motoren und Turbinen Union
(MTU); specifically Test Method DIN53521 (for nitrile seals). The
results are shown below in Table II. Where the tests were repeated
a number of times, an average result is provided. TABLE-US-00003
TABLE II Ex. 1 Ex. 2 Ex. 3 Ex. 4 Bench Test Property Limit (0)
(0.5) (1) (2) MBSEAL NBR EAB* -35% max -45 -44 -37 TS** -20% max
-20 -19 -11 V*** 0 to 10% 0 0 0 H**** -8 to +2 pts. 0 0 0 # of
tests -- >5 2 3 0 MANSEAL EAB -30% max -43 -- -36 -32 NBR TS
-20% max -23 -- -12 -12 V 0 to +10% 2 -- 2 2 H -10 pts. max -1 --
-1 -1 # of tests -- >5 0 3 2 MTUSEAL EAB -35% max -40 -34 -36
-33 NBR TS -20% max -23 -11 -16 -17 V 0 to 10% 2 2 2 2 H 0 to -10
pts. -1 -1 -1 -2 # of tests -- >5 2 2 2 *elongation at break;
**tensile strength; ***volume; ****hardness
[0109] As shown, in each of the bench tests, the addition of PIB
resulted in improved performance, particularly in terms of EAB and
TS, sufficiently to provide a passing result, where the base
formulation failed.
Example 2
[0110] A lubricating oil composition representing a low SAPS
(sulfated ash, phosphorus, sulfur) 10W40 crankcase lubricant for a
heavy duty diesel engine meeting the requirements of the ACEA E6-04
specification was prepared by blending a base stock oil of
lubricating viscosity, a detergent/inhibitor (DI) package including
salicylate detergent, dispersant, ZDDP and antifoamant; a viscosity
modifier and LOFI (lube oil flow improver). The resulting
composition had a nitrogen content of 0.16 mass %; a sulfur content
of 0.25 mass %, a sulfated ash (SASH) content of 0.25 mass % and
800 ppm of phosphorus and 24 mmol of salicylate soap per kilogram
of finished lubricant.
[0111] Four lubricating oil compositions were prepared based on the
above recipe. Example 5, a comparative example, contained no added
450 M.sub.n polybutene (PIB). Examples 2, 3 and 4, which represent
the invention, contained 2.1, 2.5 and 3.0 mass % of 950 M.sub.n
PIB, respectively. The four samples were then tested for
compatibility with nitrile rubber the bench tests described in
Example 1. The results are shown below in Table III. TABLE-US-00004
TABLE III Ex. 5 Ex. 6 Ex. 7 Ex. 8 Bench Test Property Limit (0)
(2.1) (2.5) (3.0) MBSEAL NBR EAB* -35% max. -57 -31 -33 -27 TS**
-20% max. -35 -11 -12 -11 V*** 0 to +10% 2 2 2 2 H**** -8 to +2
pts. 1 -2 1 -1 MANSEAL NBR EAB -30% max. -55 -28 -- -27 TS -20%
max. -48 -10 -- -10 V 0 to +10% 5 5 -- 5 H -10 pts. max -2 -3 --
-4
[0112] As shown, the effects of the invention are particularly
apparent in low SAPS HDD lubricants formulated with salicylate
detergents. Again, in each of the bench tests, the addition of PIB
resulted in improved performance, particularly in terms of EAB and
TS, sufficiently to provide a passing result, where the base
formulation failed.
Example 3
[0113] A lubricating oil composition representing a 15W40 crankcase
lubricant for a heavy duty diesel engine meeting the requirements
of the PC-10 specification was prepared by blending a base stock
oil of lubricating viscosity, a detergent/inhibitor (DI) package
including sulfonate and sulfurized phenate detergent, dispersant,
ZDDP, a molybdenum-sulfur compound, and antifoamant; a
dispersant/viscosity modifier and LOFI (lube oil flow improver).
The resulting composition had a sulfur content of 0.31 mass %, a
nitrogen content of 0.14, a SASH content of 0.94; 50 ppm of
molybdenum and 1000 ppm of phosphorus.
[0114] Four lubricating oil compositions were prepared based on the
above recipe. Example 9, a comparative example, contained no added
950 M.sub.n polybutene (PIB). Examples 10, 11 and 12, which
represent the invention, contained 0.5, 1.0 and 2.0 mass % of 950
M.sub.n PIB, respectively. The four samples were then tested for
compatibility with nitrile rubber in the bench tests described in
Example 1. The results are shown below in Table IV. TABLE-US-00005
TABLE IV Bench Ex. 9 Ex. 10 Ex. 11 Ex. 12 Test Property Limit (0)
(0.5) (1.0) (2.0) MBSEAL EAB* -35% max. -37 -29 -23 -21 NBR TS**
-20% max. -18 -13 -9 -7 V*** 0 to +10% 2.1 2 2 2 H**** -8 to +2
pts. -2 -2 -2 -2
[0115] As shown, the effects of the invention are also apparent in
lubricants formulated with phenate and sulfonate detergents. The
addition of PIB resulted in improved performance, specifically in
terms of EAB, sufficient to provide a passing result, where the
base formulation failed.
Example 4
[0116] Five lubricating oil compositions were prepared based on the
recipe provided in Example 3. Example 13, a comparative example,
contained no added 950 M.sub.n polybutene (PIB). Examples 14, 15,
16 and 17, which represent the invention, contained 2, 3, 4 and 5
mass % of 950 M.sub.n PIB, respectively. The five samples were then
tested for corrosion, particularly copper corrosion, using the High
Temperature Corrosion Bench Test described in ASTM D6594. The
results are shown below in Table V. TABLE-US-00006 TABLE V Ex. 14
Ex. 15 Ex. 16 Ex. 12 Property Limit Ex. 13 (2) (3) (4) (5) Cu 20
max 111 24 13 12 9 Pb 120 max 44 36 37 38 42 Sn 50 max 0 2 2 2 2 Cu
Strip 3 4B 1A 1A 1A 1A
[0117] As demonstrated, the addition of PIB to a lubricating oil
composition containing a significant sulfur content further
improves copper corrosion performance and allows passage of the
HTCBT with a formulation that fails the test in the absence of the
PIB.
[0118] The disclosures of all patents, articles and other materials
described herein are hereby incorporated, in their entirety, into
this specification by reference. A description of a composition
comprising, consisting of, or consisting essentially of multiple
specified components, as presented herein and in the appended
claims, should be construed to also encompass compositions made by
admixing said multiple specified components. The principles,
preferred embodiments and modes of operation of the present
invention have been described in the foregoing specification. What
applicants submit is their invention, however, is not to be
construed as limited to the particular embodiments disclosed, since
the disclosed embodiments are regarded as illustrative rather than
limiting. Changes may be made by those skilled in the art without
departing from the spirit of the invention.
* * * * *