U.S. patent application number 10/755015 was filed with the patent office on 2005-07-14 for graft copolymers, method of making and compositions containing the same.
Invention is credited to Mishra, Munmaya K., Srinivasan, Sanjay.
Application Number | 20050153849 10/755015 |
Document ID | / |
Family ID | 34592612 |
Filed Date | 2005-07-14 |
United States Patent
Application |
20050153849 |
Kind Code |
A1 |
Mishra, Munmaya K. ; et
al. |
July 14, 2005 |
Graft copolymers, method of making and compositions containing the
same
Abstract
Graft copolymers, particularly useful as dispersant viscosity
index improvers in lubricating oil compositions have a polymer
backbone selected from is selected from the group consisting of
olefin polymers, diene polymers, vinyl polymers and vinylidene
polymers, is grafted with an amine selected from N-p-diphenylamine,
1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl methacrylamide;
4-anilinophenyl maleimide; 4-anilinophenyl itaconamide; acrylate
and methacrylate esters of 4-hydroxydiphenylamine; the reaction
product of p-aminodiphenylamine or p-alkylaminodiphenylamine with
glycidyl methacrylate; the reaction product of p-aminodiphenylamine
with isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; vinylogous derivatives of
diphenylamine; and mixtures thereof and may be prepared in a single
step process using solution or bulk grafting conditions.
Inventors: |
Mishra, Munmaya K.;
(Richmond, VA) ; Srinivasan, Sanjay; (Richmond,
VA) |
Correspondence
Address: |
DENNIS H. RAINEAR
CHIEF PATENT COUNSEL, ETHYL CORPORATION
330 SOUTH FOURTH STREET
RICHMOND
VA
23219
US
|
Family ID: |
34592612 |
Appl. No.: |
10/755015 |
Filed: |
January 9, 2004 |
Current U.S.
Class: |
508/221 ;
508/275; 508/291; 508/452; 508/477; 508/543; 508/548; 508/551;
508/557; 525/242 |
Current CPC
Class: |
C10N 2060/09 20200501;
C10M 149/04 20130101; C10M 2205/08 20130101; C10M 149/06 20130101;
C10N 2030/02 20130101; C10M 151/04 20130101; C08F 259/00 20130101;
C08F 8/32 20130101; C10M 2205/026 20130101; C08F 255/02 20130101;
C10M 151/00 20130101; C10M 2205/024 20130101; C10M 2205/06
20130101; C10M 2221/04 20130101; C08F 257/02 20130101; C08L 51/003
20130101; C10M 2217/06 20130101; C10N 2040/25 20130101; C10N
2030/041 20200501; C08F 255/00 20130101; C10M 2217/00 20130101;
C10M 149/00 20130101; C10N 2030/50 20200501; C10M 151/02 20130101;
C08F 8/34 20130101; C08F 279/02 20130101; C08L 51/003 20130101;
C08L 2666/02 20130101 |
Class at
Publication: |
508/221 ;
508/291; 508/275; 508/452; 508/477; 508/543; 508/548; 508/551;
508/557; 525/242 |
International
Class: |
C10M 149/00 |
Claims
What is claimed is:
1. A graft copolymer comprising an polymer backbone which has been
grafted by reacting the polymer backbone with a reactant selected
from the group consisting of N-p-diphenylamine,
1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl methacrylamide;
4-anilinophenyl maleimide; 4-anilinophenyl itaconamide; acrylate
and methacrylate esters of 4-hydroxydiphenylamine; the reaction
product of p-aminodiphenylamine or p-alkylaminodiphenylamine with
glycidyl methacrylate; the reaction product of p-aminodiphenylamine
with isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; vinylogous derivatives of
diphenylamine; and mixtures thereof.
2. The copolymer of claim 1, wherein the polymer backbone is
selected from the group consisting of olefin polymers; diene
polymers, vinyl polymers and vinylidene polymers.
3. The copolymer of claim 2, wherein the polymer backbone comprises
an olefin polymer.
4. The copolymer of claim 3, wherein the polymer backbone comprises
an ethylene-olefin copolymer.
5. The copolymer of claim 1, wherein the backbone comprises an
ethylene-propylene copolymer and wherein the reactant is selected
from the group consisting of N-p-diphenylamine,
1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl methacrylamide; and
mixtures thereof.
6. The copolymer of claim 1, wherein the polymer backbone comprises
a styrene-isoprene copolymer.
7. A lubricating oil composition comprising a base oil mixed with
the graft copolymer of claim 1.
8. The oil composition of claim 7, wherein the graft copolymer
comprises from 2 weight percent to about 18 weight percent of the
oil composition.
9. The oil composition of claim 7, wherein the base oil is selected
from the group consisting of natural lubricating oils, synthetic
lubricating oils, animal oils, vegetable oils, castor oil, lard
oil, liquid petroleum oils, hydrorefined, solvent-treated or
acid-treated mineral lubricating oils of the paraffinic, naphthenic
and mixed paraffinic-naphthenic types, oils of lubricating
viscosity derived from coal or shale, poly-alpha-olefins, alkylated
aromatics, alkylene oxide polymers, interpolymers, copolymers and
derivatives thereof where the terminal hydroxyl groups have been
modified by esterification or etherification, esters of
dicarboxylic acids, and silicon oils, and mixtures thereof.
10. The oil composition of claim 7, wherein the lubricating oil
composition further comprises an additive selected from the group
consisting of zinc dialkyl dithiophosphates, friction modifiers,
corrosion inhibitors, extreme pressure agents, antioxidants,
defoamants, surfactants, detergents, and pour point
depressants.
11. An engine lubricated with an oil composition comprising the
graft copolymer of claim 1.
12. The engine of claim 11, wherein the engine is selected from the
group consisting of automotive engines, heavy and light duty truck
engines, gasoline combustion engines, diesel engines, hybrid
Internal Combustion/electric engines.
13. The engine of claim 11, wherein the engine comprises an exhaust
gas recirculation system, whereby exhaust gases comprising soot
generated in the combustion in the engine of fuel contact a
lubricating oil used to lubricate said engine.
14. The engine of claim 11, wherein the graft copolymer comprises a
viscosity index improver and a soot dispersant.
15. The engine of claim 11, wherein the graft copolymer comprises
from 2 weight percent to about 18 weight percent of the oil
composition.
16. The engine of claim 11, wherein the engine is cooled by the
circulation of a material selected from the group consisting of
water, a water/hydrocarbon mix, water/glycol mix, air, and gas.
17. The engine of claim 11, wherein the lubricating oil passes the
Mack T-11 test at a viscosity increase of less than 8 cSt at
100.degree. C. at a soot level of up to 6.09% m in the Mack T-11
test.
18. The engine of claim 11, wherein the lubricating oil has a
viscosity increase of less than 10 cSt at 100.degree. C. and up to
6.0% m soot in the Mack T-11 test.
19. A method of reducing the soot-induced thickening of a
lubricating oil used to lubricate a cooled exhaust gas
recirculating engine in which soot accumulates in the oil, said
method comprising lubricating the engine with a lubricating oil
comprising a base oil and a sufficient amount of a dispersant
viscosity index improver comprising the graft copolymer of claim
1.
20. A method of improving fuel economy of a vehicle having a cooled
exhaust gas recirculation engine, wherein said method comprises
adding to and operating in the crankcase of said vehicle a
lubricating oil composition containing a sufficient amount of the
graft copolymer of claim 1.
21. A method of improving fuel economy durability of a vehicle
having a cooled exhaust gas recirculation engine, wherein said
method comprises adding to and operating in the crankcase of said
vehicle a lubricating oil composition containing a sufficient
amount of the graft copolymer of claim 1.
22. A method of simultaneously passing the M-11 EGR test, T-10 test
(ASTM D4485 classification for API C.sub.1-4 oils), and the Mack
T-11 in cooled EGR engine, said method comprising adding to and
operating in the crankcase of the engine a lubricating oil
composition containing a sufficient amount of the graft copolymer
of claim 1.
23. A method to give superior oil sludge performance in a vehicle
with a cooled EGR engine, said method comprising adding to and
operating in the crankcase of the vehicle a lubricating oil
composition containing a sufficient amount of the graft copolymer
of claim 1, whereby the oil sludge performance is superior to the
oil sludge performance in a cooled EGR engine of an oil without the
graft copolymer of claim 1.
24. A method to give superior wear protection from soot in a
vehicle equipped with a cooled EGR engine, said method comprising
adding to and operating in the crankcase of the engine a
lubricating oil composition containing a sufficient amount of a
dispersant viscosity index improver comprising the graft copolymer
of claim 1, whereby the wear protection from soot is superior to
the wear protection from soot in a cooled EGR engine lubricated
with an oil without the graft ethylene-olefin copolymer of claim
1.
25. A method to extend the service time between oil drains in a
vehicle equipped with an exhaust gas recirculation engine up to
about 60,000 miles by the addition to a lubricating oil in the
engine of a sufficient amount of the graft copolymer of claim
1.
26. A process of making a graft copolymer comprising grafting a
reactant selected from the group consisting of N-p-diphenylamine,
1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl methacrylamide;
4-anilinophenyl maleimide; 4-anilinophenyl itaconamide; acrylate
and methacrylate esters of 4-hydroxydiphenylamine; the reaction
product of p-aminodiphenylamine or p-alkylaminodiphenylamine with
glycidyl methacrylate; the reaction product of p-aminodiphenylamine
with isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; vinylogous derivatives of
diphenylamine; and mixtures thereof onto a polymer backbone.
27. The process of claim 26, wherein the grafting is carried out in
solution.
28. The process of claim 26, wherein the grafting is carried out in
the presence of a catalyst.
29. The process of claim 28, wherein the catalyst comprises a
peroxide catalyst.
30. The process of claim 26, wherein the grafting is carried out in
bulk in a device selected from the group consisting of an extruder
and an intensive mixing device.
31. The process of claim 26, wherein the polymer backbone is
selected from the group consisting of olefin polymers; diene
polymers, vinyl polymers and vinylidene polymers.
32. The process of claim 26, wherein the polymer backbone comprises
a copolymer of ethylene, at least one C.sub.3 to C.sub.23
alpha-olefin, and optionally a non-conjugated diene or triene.
Description
FIELD
[0001] The embodiments relate to graft copolymers, lubricating
compositions comprising the graft copolymers, and engines
lubricated with such compositions. Other embodiments relate to the
process of making the graft polymers and to the use of such graft
polymers to lubricate an engine.
BACKGROUND
[0002] Lubricating oils, and more particularly those used in the
crankcase of internal combustion engines, are known to contain
various additives for improving the performance of said oils during
their use. Some additives are used to increase the oil viscosity
index while others ensure, for instance, that the insoluble
deposits that will form in the oil are maintained in a suspended
state.
[0003] The additives used for improving the oil viscosity index
must have, on the one hand, a sufficient thickening effect on a
light lubricating oil at high temperatures to make the lubricating
properties of said oil similar to those of a heavier lubricating
oil and, on the other hand, a limited thickening effect on a light
lubricating oil at low temperatures to avoid impairing the
properties of said oil at said low temperatures. They are generally
long-chain polymer compounds such as, for example, polyisobutene,
polymethacrylates, polyalkylstyrenes, partially hydrogenated
copolymers of butadiene and styrene, and amorphous copolymers of
ethylene and propene.
[0004] Additives for lubricating oils have also been proposed to
provide simultaneously the improvement of the oil viscosity index
and the dispersion of the slurry they may contain. Such additives
are, for example, graft copolymers resulting from the grafting of
acrylonitrile or aminoalkyl methacrylates on amorphous copolymers
of ethylene and propene, or also statistic copolymers obtained by
radical polymerization of acrylates or alkyl methacrylates with
vinyllactames such as N-vinylpyrrolidone or aminoalkyl
methacrylates.
[0005] Improved graft copolymers and lubricating oil compositions,
particularly for EGR engines are needed, as is an improved process
of making same.
SUMMARY OF THE EMBODIMENTS
[0006] In an embodiment is provided a graft copolymer comprising a
polymer backbone which has been reacted with an amine selected from
the group consisting of N-p-diphenylamine,
1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl methacrylamide;
4-anilinophenyl maleimide; 4-anilinophenyl itaconamide; acrylate
and methacrylate esters of 4-hydroxydiphenylamine; the reaction
product of p-aminodiphenylamine or p-alkylaminodiphenylamine with
glycidyl methacrylate; the reaction product of p-aminodiphenylamine
with isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; vinylogous derivatives of
diphenylamine; and mixtures thereof.
[0007] In another embodiment is provided a process of making a
graft copolymer comprising the step of grafting a polymer backbone
with an amine reactant selected from the group consisting of
N-p-diphenylamine, 1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl
methacrylamide; 4-anilinophenyl maleimide; 4-anilinophenyl
itaconamide; acrylate and methacrylate esters of
4-hydroxydiphenylamine; the reaction product of
p-aminodiphenylamine or p-alkylaminodiphenylamine with glycidyl
methacrylate; the reaction product of p-aminodiphenylamine with
isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; vinylogous derivatives of
diphenylamine; and mixtures thereof.
[0008] A lubricating oil composition is provided in an embodiment,
comprising a base oil and a polymer backbone which has been grafted
with a reactant selected from the group consisting of
N-p-diphenylamine, 1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl
methacrylamide; 4-anilinophenyl maleimide; 4-anilinophenyl
itaconamide; acrylate and methacrylate esters of
4-hydroxydiphenylamine; the reaction product of
p-aminodiphenylamine or p-alkylaminodiphenylamine with glycidyl
methacrylate; the reaction product of p-aminodiphenylamine with
isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; vinylogous derivatives of
diphenylamine; and mixtures thereof. In an embodiment, the graft
copolymer is used as a viscosity index improver and is present in
the oil composition in an amount sufficient to reduce the amount of
oil thickening of the lubricating oil.
[0009] A further embodiment provides a lubricated engine comprising
an exhaust gas recirculation system, whereby exhaust gases
comprising soot generated in the combustion in the engine of fuel
contact a lubricating oil used to lubricate said engine, wherein
said lubricating oil comprises: a base oil and a graft copolymer
comprising a polymer backbone which has been grafted with a
reactant selected from the group consisting of N-p-diphenylamine,
1,2,3,6-tetrahydrophthalimide; 4-anilinophenyl methacrylamide;
4-anilinophenyl maleimide; 4-anilinophenyl itaconamide; acrylate
and methacrylate esters of 4-hydroxydiphenylamine; the reaction
product of p-aminodiphenylamine or p-alkylaminodiphenylamine with
glycidyl methacrylate; the reaction product of p-aminodiphenylamine
with isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; vinylogous derivatives of
diphenylamine; and mixtures thereof.
[0010] Another important embodiment provides a graft copolymer
dispersant viscosity index improver that is free of any maleic
anhydride moiety.
[0011] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are intended to provide further
explanation of the present invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWING FIGURE
[0012] FIG. 1 is a graph showing viscosity increase in test oils in
connection with the Mack T-11 Test procedure.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0013] The polymer backbone used for making the graft copolymers of
the embodiments may include polyisobutene, polyalkylstyrenes,
partially hydrogenated polyolefins of butadiene and styrene,
amorphous polyolefins of ethylene and propylene, and isoprene
copolymers. The polymers contemplated for use include olefin
polymers such as various forms of polyethylene, propylene,
isoprene, ethylene-propylene copolymers, and the like; polymers
from dienes including styrene butadiene rubber, polyisoprene,
ethylene-propylene diene terpolymers (EPDM), and the like; and
vinyl and vinylidene polymers including acrylic polymers such as
polymethylmethacrylate, polystyrene and its family of copolymers
such as butadiene-styrene, and the like.
[0014] As used herein, the term "polymer" is used broadly to
encompass any molecule that is comprised of one or more repeating
monomer units, and includes copolymers, terpolymers, interpolymers,
etc. The term "copolymer" is used broadly to mean any polymer that
is comprised of more than one monomer unit.
[0015] Copolymers of ethylene and one or more C.sub.3 to C.sub.23
alpha-olefins and polymers and copolymers of isoprene are useful.
Copolymers of ethylene and propylene are very effective. Other
alpha-olefins suitable in place of propylene to form the copolymer
or to be used in combination with ethylene and propylene to form a
terpolymer include 1-butene, 1-pentene, 1-hexene, 1-octene and
styrene; .alpha.,.omega.-diolefins such as 1,5-hexadiene,
1,6-heptadiene, 1,7-octadiene; branched chain alpha-olefins such as
4-methylbutene-1,5-methylpentene-1 and 6-methylheptene-1; and
mixtures thereof.
[0016] More complex polymer backbones, often designated as
interpolymers, may be prepared using a polyene monomer selected
from non-conjugated dienes and trienes. The non-conjugated diene
component is one having from 5 to 14 carbon atoms in the chain. In
one embodiment, the diene monomer is characterized by the presence
of a vinyl group in its structure and can include cyclic and
bicyclo compounds. Representative dienes include 1,4-hexadiene,
1,4-cyclohexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene,
5-methylene-2-norborene, 1,5-heptadiene, and 1,6-octadiene. A
mixture of more than one diene can be used in the preparation of
the interpolymer. In another embodiment, a non-conjugated diene for
preparing a terpolymer or interpolymer backbone is
1,4-hexadiene.
[0017] The triene component will have at least two non-conjugated
double bonds, and up to about 30 carbon atoms in the chain. Typical
trienes useful in preparing the interpolymer of the invention are
1-isopropylidene-3.alpha.,4,7,7.alpha.-tetrahydroindene,
1-isopropylidenedicyclopentadiene, dihydro-isodicyclopentadiene,
and
2-(2-methylene-4-methyl-3-pentenyl)[2.2.1]bicyclo-5-heptene.
[0018] Ethylene-propylene or higher alpha-olefin copolymers may
consist of from about 15 to 80 mole percent ethylene and from about
85 to 20 mole percent C.sub.3 to C.sub.23 alpha-olefin with the
mole ratios being from about 35 to 75 mole percent ethylene and
from about 65 to 25 mole percent of a C.sub.3 to C.sub.23
alpha-olefin. In another embodiment, the proportions are from 50 to
70 mole percent ethylene and 50 to 30 mole percent C.sub.3 to
C.sub.23 alpha-olefin. In yet another example, the proportions are
from 55 to 65 mole percent ethylene and 45 to 35 mole percent
C.sub.3 to C.sub.23 alpha-olefin. Terpolymer variations of the
foregoing polymers may contains from about 0.1 to 10 mole percent
of a non-conjugated diene or triene.
[0019] The polymer backbone can be an oil-soluble, linear or
branched polymer having a weight average molecular weight of from
about 20,000 to about 500,000 and polydispersities from about 1 to
about 15.
[0020] Saturated and partially unsaturated polymers are useful. The
polymer backbone may be crystalline, semi-crystalline, or amorphous
types of the aforementioned polymers and copolymers are also
contemplated for use in the methods of this invention. High Mooney
amorphous polymers are also suitable.
[0021] Specific materials which may be useful as the polymer
backbone include: Mitsui XLL-10, XLM-12, XLH-15 and XLH-17
amorphous ethylene/propylene rubbers sold by Mitsui Petrochemical
Industries, Ltd., Tokyo, Japan; VISTALON ethylene/propylene
polyolefins, sold by Exxon Chemical Americas, Houston, Tex.; Shell
Vis polymers, such as, SV-250 hydrogenated isoprene copolymer,
SV-200 and SV-300 styrene/isoprene polymers, and SV-40 and SV-50
styrene/butadiene polymers sold by Shell Chemical Co., Houston,
Tex.; Dutral CO and Dutral CT amorphous ethylene/propylene
elastomers, such as, CO-034 and C-043, Buna EPM copolymers sold by
Bayer Corporation, Akron, Ohio; and Lubrizol.RTM.-7441 and -7340
polymers sold by Lubrizol Corporation, Wickliffe, Ohio.
[0022] Combinations and mixtures of polymers of the types mentioned
above may also be used to advantage.
[0023] The polymerization reaction used to form the polymer
backbone is generally carried out in the presence of a catalyst.
Ziegler-Natta and metallocene catalysts are typical, particularly
for making ethylene-propylene copolymers. The polymerization medium
is not specific and can include solution, slurry, or gas phase
processes, as known to those skilled in the art. When solution
polymerization is employed, the solvent may be any suitable inert
hydrocarbon solvent that is liquid under reaction conditions for
polymerization; examples of satisfactory hydrocarbon solvents
include straight chain paraffins having from 5 to 8 carbon atoms.
Hexane is a particularly useful solvent for making
ethylene-propylene copolymers. Aromatic hydrocarbons, preferably
aromatic hydrocarbon having a single benzene nucleus, such as
benzene, toluene and the like; and saturated cyclic hydrocarbons
having boiling point ranges approximating those of the straight
chain paraffinic hydrocarbons and aromatic hydrocarbons described
above, are particularly suitable. The solvent selected may be a
mixture of one or more of the foregoing hydrocarbons. When slurry
polymerization is employed, the liquid phase for polymerization is
preferably liquid propylene. It is desirable that the
polymerization medium be free of substances that will interfere
with the catalyst components.
[0024] An amine reactant is grafted onto the prescribed polymer
backbone to form the resulting graft copolymer. The amine reactants
are selected from the group consisting of N-p-diphenylamine,
1,2,3,6-tetrahydrophthali- mide; 4-anilinophenyl methacrylamide;
4-anilinophenyl maleimide; 4-anilinophenyl itaconamide; acrylate
and methacrylate esters of 4-hydroxydiphenylamine; the reaction
product of p-aminodiphenylamine or p-alkylaminodiphenylamine with
glycidyl methacrylate; the reaction product of p-aminodiphenylamine
with isobutyraldehyde, derivatives of p-hydroxydiphenylamine;
derivatives of phenothiazine; and vinylogous derivatives of
diphenylamine. Mixtures of these reactants may also be used to
advantage.
[0025] The amine reactants have the following structures:
[0026] N-p-diphenylamine, 1,2,3,6-tetrahydrophthalimide: 1
[0027] 4-anilinophenyl methacrylamide: (available under the
tradename POLYSTAY.RTM. from Goodyear Tire & Rubber Co. in
Akron, Ohio) 2
[0028] N-(4-anilinophenyl) maleimide: 3
[0029] N-(4-anilinophenyl) itaconamide: 4
[0030] Acrylate and methacrylate esters of 4-hydroxydiphenylamine
5
[0031] wherein R is selected from the group consisting of H and an
alkyl having 1 to 4 carbon atoms.
[0032] The reaction product of p-aminodiphenylamine or
p-alkylaminodiphenylamine with glycidyl methacrylate: 6
[0033] wherein R is selected from the group consisting of H and an
alkyl having 1 to 4 carbon atoms.
[0034] Vinylogous diphenylamine derivatives: 7
[0035] wherein A is selected from:
[0036] --CH.sub.2SO.sub.2NH--; --SO.sub.2NH--; 8
[0037] The reaction product of p-aminodiphenylamine with
isobutyraldehyde: 9
[0038] p-Hydroxydiphenylamine derivatives: 10
[0039] wherein R.sub.1 and R.sub.2 may be the same or different and
are selected from the group of radicals consisting of hydrogen,
alkyls having 1 to 18 carbon atoms, aryls having 6 to 18 carbon
atoms, alkaryls having 7 to 18 carbon atoms and aralkyls having 7
to 18 carbon atoms;
[0040] wherein R.sub.3 and R.sub.4 may be the same or different and
are selected from the group of radicals consisting of hydrogen and
methyl; and
[0041] wherein R.sub.5 is a radical selected from the group
consisting of alkenyls having 2 to 18 carbon atoms.
[0042] Phenothiazine derivatives: 11
[0043] wherein R.sub.1 and R.sub.2 may be the same or different and
are selected from the group of radicals consisting of hydrogen,
alkyls having 1 to 18 carbon atoms, aryls having 6 to 18 carbon
atoms, alkaryls having 7 to 18 carbon atoms and aralkyls having 7
to 18 carbon atoms;
[0044] wherein R.sub.3 and R.sub.4 may be the same or different and
are selected from the group of radicals consisting of hydrogen and
methyl; and
[0045] wherein R.sub.5 is a radical selected from the group
consisting of alkenyls having 2 to 18 carbon atoms, and w 1.
[0046] In one embodiment, the amine reactant is grafted onto the
prescribed polymer backbone to provide a graft polymer having from
0.5 to 10 weight percent of the pendent groups. In another
embodiment, the pendent groups will comprise from 1 to about 8
weight percent of the graft copolymer. The amount of amine
reactants desired in the final polymer will depend on the desired
end properties and intended use of the graft polymer. For one
embodiment, the minimum level of functionality is the level needed
to achieve the minimum satisfactory dispersancy performance in the
lubricated cooled EGR engines.
[0047] Grafting of the amine-functional monomer onto the polymer
backbone can be accomplished either in solution using a solvent or
under reactive extrusion conditions in the presence or absence of
solvent. The amine-functional monomer may be grafted onto the
polymer backbone in multiple ways. In one embodiment, the grafting
takes place by a thermal process via an "ene" reaction. In another
embodiment the grafting is carried out in solution or solid form
through a free radical initiator. Solution grafting is a well known
method for producing grafted polymers. In such a process, reagents
are introduced either neat or as solutions in appropriate solvents.
The desired polymer product must sometimes then be separated form
the reaction solvents and/or impurities by appropriate purification
steps.
[0048] The free radical catalyzed grafting of the polymer with the
functional monomers can be carried out in solvents like benzene,
toluene, xylene, or hexane. The reaction is carried out at an
elevated temperature in the range of 100.degree. C. to 250.degree.
C., preferably 120.degree. C. to 230.degree. C., and more
preferably at 160.degree. C. to 200.degree. C., e.g. above
160.degree. C., in a solvent, preferably a mineral lubricating oil
solution containing, e.g. 1 to 50, preferably 5 to 40 wt. %, based
on the initial total oil solution of the said polymer and
preferably under an inert environment.
[0049] The free-radical initiators that may be used include
peroxides, hydroperoxides, and azo compounds. Particularly useful
are free-radical initiators that have a boiling point greater than
about 100.degree. C. and decompose thermally within the grafting
temperature range to provide free radicals. Examples of such
initiators include alkyl and dialkyl peroxides, aryl and diaryl
peroxides diacyl peroxides, ketone peroxides, peroxydicarbonates,
peroxyesters, peroxyketals, hydroperoxides and azo initiators.
Representative initiators are disclosed in U.S. Pat. No. 4,146,489,
which is incorporated herein by reference. Specific initiators
contemplated herein include, for example, di-t-butyl peroxide;
dicumyl peroxide; t-butyl-cumyl peroxide; t-butyl perbenzoate;
t-amyl perbenzoate; t-butyl peroxyacetate; t-butyl peroxy benzoate;
t-butyl peroctoate; benzoyl peroxide; di-t-butyl peroxy phthalate;
2,5,-dimethyl-2,5,-di(t-butyl peroxy)hexane;
2,5,-dimethyl-2,5,-di(t-buty- l peroxy)hexyne; butanenitrile,
2-methyl, 2,23-azobis; propanenitrile, 2-methyl, 2,23-azobis;
2,23-azobis(2,4-dimethylpentane nitrile);
1,13-azobis(cyclohexanecarbonitrile); azoisobutyronitrile (AIBN);
hydrogen peroxide; 2,5-dihydroperoxy-2,5-dimethyl hexane
(Luperox.RTM., Elf Atochem, Philadelphia, Pa.); cumene
hydroperoxide; t-butylhydroperoxide; t-amylhydroperoxide. Any of
the above classes of initiators or specifically listed initiators
may be used in combination to provide optimal radical initiation
throughout the entire reaction process. In one embodiment, the
grafting reaction is carried out in solution in the presence of a
peroxide catalyst.
[0050] Each such initiator commonly has a characteristic minimum
temperature, above which it will readily initiate a reaction and
below which initiation will proceed more slowly or not at all.
Consequently, the minimum reaction temperature is commonly dictated
by the effective characteristic minimum initiation temperature of
the initiator.
[0051] One category of solvents useful herein is that of volatile
solvents that are readily removable from the grafted polyolefin
after the reaction is complete. Any solvent may be used which can
disperse or dissolve the remaining components of the reaction
mixture and which will not participate appreciably in the reaction
or cause side reactions to a material degree. Exemplary solvents of
this type include straight chain or branched aliphatic or alicyclic
hydrocarbons, such as n-pentane, n-heptane, i-heptane, n-octane,
i-octane, nonane, decane, cyclohexane, dihydronaphthalene,
decahydronaphthalene and others. Aliphatic ketones (for example,
acetone), ethers, esters, etc., and mixtures thereof are also
contemplated as solvents herein. Nonreactive halogenated aromatic
hydrocarbons such as chlorobenzene, dichlorobenzene,
di-chlorotoluene and others are also useful as solvents.
[0052] Another category of solvents useful herein is a base oil
stock which has a low aromatic content and which will be suitable
for incorporation into a final lubricating oil product. Any base
oil may be used which can disperse or dissolve the remaining
components of the reaction mixture without materially participating
in the reaction or causing side reactions to an unacceptable
degree. Specifically, hydrocracked base oils, base oils naturally
containing low levels of aromatic constituents, and fluid
poly-.alpha.-olefins are contemplated for use herein. Aromatic
constituents should be kept to low levels (if present at all),
since aromatic materials may be reactive with each other or other
reaction components, particularly in the presence of initiators.
The other reaction components thus may either be wasted, or produce
unwanted by-products, unless the presence of aromatic constituents
is small. Use of base stocks having aromatic constituents, while
being less than optimum, is not excluded.
[0053] The level of aromatic constituents in a refined petroleum
oil is sometimes expressed as the weight percentage of molecular
species containing any proportion of aromatic carbon atoms, and
other times is expressed as the weight percentage of only the
aromatic carbon atoms. The former value can be much greater than
the latter value. In this specification, the "level of aromatic
constituents" is defined as the weight percentage of molecular
species containing any proportion of aromatic carbon atoms. The
petroleum oil solvents contemplated here are those containing less
than about 20% by weight of molecular aromatic impurities,
alternatively less than about 5% by weight of such impurities,
alternatively less than about 1% of such impurities, alternatively
about 0.2% or less of such impurities.
[0054] Also contemplated for use herein are oils prepared by
sulphonation technology like Witco LMW Co-oil R-211-0, for which
the aromatic content is about 0.1-5 wt %. Further contemplated for
use herein are the no aromatic content oils, which are synthetic
lubricant base stocks like PAO.
[0055] It is well known that solution grafting of polymers in
mineral oil can lead to cross-linking of the polymer and grafting
of the oil with the monomer. The resulting grafted polymer differs
significantly in its thickening efficiency and shear stability from
the starting polymer, which is not desirable. This can be a
disadvantage when the graft copolymers are to be used as
lubricating oil additives. To overcome this problem, it is
desirable to conducting the solution grafting reaction at elevated
temperatures (i.e., >190.degree. C.) in mineral oil using
t-butyl peroxide. By carrying out the polymer grafting reaction at
190.degree. C. or above, one can suppress or minimize
homopolymerization of the functional monomer as well as minimize
cross-linking of the polymer and undesired reactions such as
grafting the oil by the functional monomer. The high concentration
of free radicals generated at the high temperature greatly
facilitates the abstraction of hydrogen from the polymer backbone
and thereby increases the grafting efficiency with minimal side
reactions.
[0056] The present reaction can be carried out as follows. The
polymer to be grafted is provided in fluid form. For example, the
polymer may be ground and dissolved in a reaction solvent, which
may be a base oil for a lubricating composition or another suitable
solvent. When the polymerization is carried out in hexane solution,
it is economically convenient but not required herein to carry out
the grafting reaction in hexane as described in U.S. Pat. Nos.
4,670,515 and 4,948,842, incorporated herein by reference. This
step can be carried out under an inert gas blanket, or with an
inert gas purge, at a temperature lower than the reaction
temperature, typically from 60.degree. C. to about 120.degree. C.,
for example, about 100.degree. C. The mixing temperature will
normally be less than the reaction temperature. Holding the mixture
at a higher temperature may degrade the components while they are
still exposed to some degree to oxygen from the atmosphere. The
reaction mixture can also be prepared as a melt of the desired
polymer, with or without any added solvent or plasticizer.
[0057] The reaction mixture thus formed is placed in a suitable
reactor that is purged or blanketed with an inert gas (which may
be, for example, nitrogen, carbon dioxide, helium, or argon). A
tank reactor may be used or, particularly if the reaction is
carried out using a molten polymer, an extrusion reactor may be
used.
[0058] The polymer solution or melt is heated to the desired
reaction temperature. At a minimum, the reaction temperature should
be sufficient to consume substantially all of the selected
initiator during the time allotted for the reaction. Different
initiators work at different rates according to the reaction
temperature, and thus will require adjustments of the reaction
temperature. After the reaction solution has reached the selected
reaction temperature, the purge can be redirected to flow over the
surface of the reaction mixture. At this time the reactants are
ready to be added.
[0059] The contemplated proportions of the graft monomer to the
polymer and reaction conditions are selected so that an effective
percentage or most or all of the molecules of the monomer will
graft directly onto the polymer, rather than forming dimeric,
oligomeric, or homopolymeric graft moieties or entirely independent
homopolymers. At the same time, a high loading of the graft monomer
onto the polymeric backbone is contemplated. The minimum molar
proportions of the graft monomer to the starting polymer are in the
range of 15 to 100 moles of the graft monomer per mole of the
starting polymer, said range including all numbers encompassed
therein. The contemplated maximum molar proportions of the graft
monomer to the starting polymer are from 20 to 120 moles or more of
the graft monomer per mole of the starting polymer, said range
including all numbers encompassed therein. The graft monomer may be
introduced into the reactor all at once, in several discrete
charges, or at a steady rate over an extended period. The monomer
can be added at a substantially constant rate, or at a rate that
varies with time. The graft monomer may be added neat, in solid or
molten form, or cut back with a solvent.
[0060] The contemplated proportions of the initiator to the monomer
and the reaction conditions are selected so that at least many and
ideally all of the molecules of the monomer will graft directly
onto the polymer, rather than forming dimeric, oligomeric, or
homopolymeric graft moieties or entirely independent homopolymers.
The minimum molar proportions of the initiator to the graft monomer
are from about 0.05:1 to about 1:1. The initiator can be added
before, with or after the monomer, so the amount of unreacted
initiator that is present at any given time is much less than the
entire charge, and preferably a small fraction of the entire
charge. In one embodiment, the initiator may be added after all the
monomer has been added, so there is a large excess of both the
monomer and the polymer present during substantially the entire
reaction. In another embodiment, the initiator may be added along
with the monomer, either at the same rate (measured as a percentage
of the entire charge added per minute) or at a somewhat faster or
slower rate, so there is a large excess of the polymer to unreacted
initiator, but so the amount of the unreacted monomer is comparable
to the amount of unreacted initiator at any given time during the
addition.
[0061] The initiator may be introduced into the reactor in several
(or, alternatively, many) discrete charges, or at a steady rate
over an extended period. The initiator can be added at a
substantially constant rate, or at a rate that varies with time.
While the initiator can be added neat, it is preferably cut back
with a solvent to avoid high localized proportions of the initiator
as it enters the reactor. In one embodiment, it is substantially
diluted with the reaction solvent. The initiator can be diluted by
at least about 5 times, alternatively at least about 10 times,
alternatively at least about 20 times its weight or volume with a
suitable solvent or dispersing medium.
[0062] After the addition of reactants is completed, the reaction
mixture is preferably mixed with heating for an additional 2-120
minutes, to completion. The time required for completion of the
reaction can be determined by experiment, by determining when the
proportion of nitrogen, or the grafted monomer in solution reaches
a value at or approaching a minimum pre-established value, or when
the viscosity approaches a near constant value.
[0063] While solution grafting has the advantages of using a
relatively simplified process it does have some disadvantages in
terms of side reactions and impurities, cross-linking of the
polymer, grafting of the oil, availability and costs of solvent,
practicality and economics of purification procedures, lower yield,
insufficient degree of graft, product quality, as well as costs and
logistics of transporting and storing the end product.
[0064] Methods that describe of preparation of grafted polymer
products for application as dispersant viscosity index improvers in
lubrication oil compositions require that the reaction polymer
product be further processed in order to achieve the desired
physical characteristics. For instance, to achieve a desired shear
stability index (SSI), a measure of potential for in-service
viscosity loss, the polymer product must be subjected to
homogenization (i.e. mechanical shearing) in order to create a
polymer product with uniform and consistent viscosity
characteristics. The presence of undesirable reaction by-products
is responsible, in part, for the necessity of such further
processing. Thus, reducing the formation of reaction side products
may also reduce or eliminate the necessity for downstream
homogenization in order to achieve a polymer product with the
desired finished characteristics.
[0065] Reactive extrusion grafting is another method for
incorporating nitrogen, oxygen, and sulfur containing functionality
on the polymer backbone and this method has certain advantages over
the solution grafting method. Examples of extruders include single
screw extruder and a co-rotating, twin-screw extruder. When using
an extrusion polymerization process, devolatilization of the
grafted polymer preferably occurs in one or more decompression
sections of the extruder.
[0066] Also known are processes for carrying out multiple
sequential chemical reactions on polymeric feedstock carried out in
an extruder with multiple reaction zones. A key feature of the
process is the removal of impurities from one reaction zone before
a subsequent reaction occurs in a subsequent reaction zone in the
extruder. Feeding water upstream of the first reaction zone leads
to less colored products. Water may also be fed prior to the
grafting reaction zone. It is understood that the water is not
incorporated into the polymer when using the procedure outlined for
introduction of the water into the extruder. Such processes are
described in, for example, U.S. Pat. Nos. 5,424,367 and 5,552,096,
incorporated herein by reference.
[0067] It is apparent from the above discussion that a variety of
graft copolymers can be prepared according to the embodiments,
including copolymers that are substantially or completely free of
any maleic anhydride moieties. Maleic anhydride moiety free
copolymers can easily be prepared, for example, by using an
ethylene-propylene copolymer backbone and reacting it with, for
example, 4-anilinodiphenyl methacrylamide.
[0068] In one embodiment, the grafting process provides
amine-functional graft copolymers in a single step process. This is
a significant advantage over most prior art processes in which a
polymer backbone is reacted with, for example, a carboxylic acid
reactant to form a graft copolymer, which then needs to be reacted
again (i.e., neutralized) to obtain the anime-functional graft
copolymer.
[0069] The graft copolymers of the embodiments will exhibit
superior dispersant properties (as measured by the Sludge
Dispersancy Test (SDT)). This test measures the ability of the
dispersant to suspend and move sludge chromatographically along
blotter paper. When a dispersant candidate is used, oil movement
along the paper results in two rings. The inner ring constitutes
the sludge being transported by the dispersant, and the outer ring
comprises the base oil. The effectiveness of the dispersant is
defined by the ratio of the diameter of the inner ring to the
diameter of the outer ring. The higher the ratio for a particular
candidate, the better the performance of that candidate as a
dispersant. In each test, 6 wt. % of the additive will be mixed
with 94% of a severely used oil from a VE engine test. The used
oil, when stored overnight at 149.degree. C. has given a
dispersancy of 30 to 35% as defined by the ratio of the diameter of
the inner ring of undispersed sludge on blotter paper to the
diameter of the outer oil ring, times 100.
1TABLE I SLUDGE DISPERSANCY TEST Additive SDT Result Control <35
Comparative Example 1 >50 Comparative Example II >50
[0070] U.S. Pat. No. 5,523,008, the disclosure of which is
incorporated herein by reference, provides a test that can be used
to determine proportions of nitrogen on the grafted polymer product
and on any process fluids (assuming the reaction is carried out in
the presence of a solvent and that solvent is not "flashed" or
physically removed in some manner during the process). The results
of this test can be used to determine the degree of grafting. If
the grafted polymer products of the process of this invention
contain any residual solvent, the solvent can be separated form the
desired product by the methods described.
[0071] The level of grafted monomer can be determined using
Infrared spectroscopy; a typical unit being the Perkin-Elmer GX
2000 Custom FTIR spectrometer. A suitable method is as follows: The
polymer is dissolved in base oil, such as Excel 110N Gr.II oil and
is then precipitated from the homogeneous solution using heptane
followed by acetone or isopropyl alcohol. Sample of polymer in oil
is diluted .about.50% in pentane. While stirring, IPA is added
dropwise, until a consistent flock is observed. The sample is
stirred an additional 5 minutes and then allowed to settle for
several hours (typically overnight). The pentane/IPA is decanted or
pipetted out of the sample jar. The polymer is then redissolved in
pentane and the above procedure is repeated. Alternatively, the
sample may be dialyzed in pentane using a latex finger cot for a
dialysis membrane. After 16 hours reflux, the dialysis residue is
transferred to a jar and the pentane is sparged off using nitrogen
and a steam bath.
[0072] A thin film is then prepared by placing the precipitate
between Teflon.RTM. sheets, pressed for 30-60 sec at 20,000
lb-24,000 lb and 150.degree. C. in a hydraulic press. The film is
then mounted on the IR beam and the spectrum generated over the
range of frequencies from 600 cm.sup.-1 to 4000 cm.sup.-1. In the
case of 4-anilinophenyl methacrylamide as the grafted amine
containing monomer, the spectral regions of interest are those due
to the anilinophenyl methacrylamide moiety with peaks between
3310-3352 cm.sup.-1 due amide/amine stretch, 1658 cm.sup.-1 due to
amide carbonyl and 1598 cm.sup.-1 due to C--NH deformation (defined
as Region 1) and those due to the polymer methylene group which
ranges from about 685 cm.sup.-1 to about 790 cm.sup.-1 (defined as
Region 2). The areas under these spectral regions, 1 and 2, are
then determined by integration and the relative area of the product
and is compared to that of a grafted polymer sample of a known
dispersant functionality concentration. Based upon relative
responses of "known" sample to "unknown" sample, the concentration
of dispersant functionality may be established.
[0073] In one embodiment, the graft copolymers are is used as a
soot dispersant viscosity index improver (DVII) in exhaust gas
recirculation (EGR) engines, particularly cooled EGR engines. The
cooled EGR engines include automotive engines, heavy and light duty
diesel and gasoline truck engines, gasoline combustion engines,
diesel engines, and hybrid internal combustion/electric engines.
These can include EGR engines cooled by the circulation or heat
exchange of water, water/hydrocarbon blends or mixtures,
water/glycol mixtures, and/or air or gas. It is of course
understood that other embodiments provide for the use of the graft
copolymers in lubricating oil compositions for conventional, i.e.,
non-recirculating, engines as well.
[0074] The graft copolymer DVIIs used to lubricate the cooled EGR
engines can be incorporated into a lubricating oil in any
convenient way. Thus, the graft copolymers can be added directly to
the lubricating oil by dispersing or dissolving the same in the
lubricating oil at the desired level of concentration. Such
blending into the lubricating oil can occur at room temperature or
elevated temperatures. Alternatively, the graft copolymers can be
blended with a suitable oil-soluble solvent/diluent (such as
benzene, xylene, toluene, lubricating base oils and petroleum
distillates) to form a concentrate, and then blending the
concentrate with a lubricating oil to obtain the final formulation.
Such additive concentrates will typically contain (on an active
ingredient basis) from about 3 to about 45 wt. %, and often from
about 10 to about 35 wt. %, of graft copolymer additive, and more
often from about 40 to 60 wt %, base oil based on the concentrate
weight.
[0075] The graft copolymer products useful in lubricating oils to
lubricate engines find their primary utility in lubricating oil
compositions, which employ a base oil in which the additives are
dissolved or dispersed. Such base oils may be natural, synthetic or
mixtures thereof. Base oils suitable for use in preparing the
lubricating oil compositions of the present invention include those
conventionally employed as crankcase lubricating oils for
spark-ignited and compression-ignited internal combustion engines,
such as automobile and truck engines, marine and railroad diesel
engines, and the like.
[0076] In the preparation of lubricating oil formulations it is
common practice to introduce the additives in the form of 10 to 80
wt. % active ingredient concentrates in hydrocarbon oil, e.g.
mineral lubricating oil, or other suitable solvent. Usually these
concentrates may be diluted with 3 to 100, e.g., 5 to 40, parts by
weight of lubricating oil per part by weight of the additive
package in forming finished lubricants, e.g. crankcase motor oils.
The purpose of concentrates, of course, is to make the handling of
the various materials less difficult and awkward as well as to
facilitate solution or dispersion in the final blend. Thus, the
graft copolymer DVII would usually be employed in the form of a 10
to 50 wt. % concentrate, for example, in a lubricating oil
fraction.
[0077] The amount of dispersant viscosity index improver in the
lubricating oil in the cooled EGR engine can be from about 20 wt. %
to about 18 wt. %.
[0078] The graft copolymer DVIIs used in an oil to lubricate the
cooled EGR engines of the embodiments will generally be used in
admixture with a lube oil basestock, comprising an oil of
lubricating viscosity, including natural lubricating oils,
synthetic lubricating oils and mixtures thereof. Natural oils
include animal oils and vegetable oils (e.g., castor, lard oil),
liquid petroleum oils and hydrorefined, solvent-treated or
acid-treated mineral lubricating oils of the paraffinic, naphthenic
and mixed paraffinic-naphthenic types. Oils of lubricating
viscosity derived from coal or shale are also useful base oils. The
synthetic lubricating oils used in this invention include one of
any number of commonly used synthetic hydrocarbon oils, which
include, but are not limited to, poly-alpha-olefins, alkylated
aromatics, alkylene oxide polymers, interpolymers, copolymers and
derivatives thereof where the terminal hydroxyl groups have been
modified by esterification, etherification etc, esters of
dicarboxylic acids and silicon-based oils. The lubricating oils may
also contain additives selected from the group consisting of zinc
dialkyl dithiophosphates, friction modifiers, antioxidants,
defoamants, surfactants, corrosion inhibitors, extreme pressure
agents, detergents, and pour point depressants.
[0079] Other embodiments provide a method of improving fuel economy
and fuel economy durability of a vehicle having a cooled EGR
engine, wherein said method comprises adding to and operating in
the crankcase of the vehicle the lubricating oil composition
containing the graft copolymer DVII described herein. The improved
durability can extend the service time between oil drains in a
vehicle equipped with an exhaust gas recirculation engine up to
about 60,000 miles by the use a lubricating oil comprising the
graft copolymer described herein in the engine.
[0080] Also provided is a method of simultaneously passing the M-11
EGR and T-10 tests (ASTM D4485 classification for C1-4 oils D02.B0
C1-4 Ballot) and the Mack T-11 test, which are cooled EGR engines.
Said method comprises adding to and operating in the crankcase of
the vehicle the lubricating oil composition containing the graft
copolymer DVII described above.
[0081] The graft copolymers used in the oils to lubricate the
cooled EGR engines of the embodiments may be post-treated so as to
impart additional properties necessary or desired for a specific
lubricant application. Post-treatment techniques are well known in
the art and include boronation, phosphorylation, and
maleination.
[0082] Lubricating oils containing the graft copolymers of the
embodiments show superior engine performance. The Cummins M11 High
Soot Test (HST) is run in a heavy-duty diesel engine under high
soot conditions to evaluate oil performance with regard to valve
train wear, sludge deposits, and oil filter plugging. This test
method as described in the ASTM D 6838-02 document uses a Cummins
M11 330 E 11I in-line turbocharged six-cylinder heavy-duty diesel
engine. Test operation includes a 25-minute warm-up, a 2-hour
break-in, and 200-hour run in four stages at 50 hours each. During
stages A and C, the engine is operated with retarded fuel injection
timing and is overfueled to generate excess soot. During stages B
and D, the engine is operated at higher load conditions to induce
valve train wear. Oil performance is determined by assessing valve
cross-head wear, sludge deposits, and oil filter plugging.
2TABLE II CUMMINS M11 EGR PERFORMANCE IN 15W40 OILS Blend 1 Blend 2
Component Wt. % Wt. % Non-dispersant VII "A" 5.00 16.00 Example 1
5.00 0.00 PPD 0.20 0.20 Dispersant 7.53 8.03 Detergent 5.16 4.31
anti-wear + anti-oxidant + friction modifier + rust 2.65 3.51
inhibitor anti-foam agent 0.01 0.01 Base oil A 74.45 67.94 Total
100.00 100.00 Crosshead Avg. Wear, Wt mg (20 max.) <20 64.94
Average Sludge (7.8 min.) 8.7-9.0 8.95 Filter Delta P, kPa (275
max.) <30 157.20 Soot Wt. % 8.50-9.0 8.90 Test Hours 300 300
[0083]
3TABLE III CUMMINS M11 HIGH SOOT TEST PERFORMANCE IN 15W40 OILS
Blend 3 Blend 4 Component Wt. % Wt. % Non-dispersant VII "B" 0.00
7.20 Example 1 8.30 0.00 PPD 0.20 0.20 Dispersant 5.03 9.50
Detergent 3.95 3.95 anti-wear + anti-oxidant + friction modifier +
rust 2.45 2.47 inhibitor anti-foam agent 0.01 0.01 Base oil B 80.06
76.67 Total 100.00 100.00 Crosshead Avg. Wear, Wt mg (20 max.)
<6 3.2 Average Sludge (7.8 min.) 9.0 8.6 Filter Delta P, kPa
(275 max.) <40 112.0 Soot Wt. % 5.0-5.4 5.4 Test Hours 200
200
[0084] 15W40 Blend 1 containing graft copolymer according to the
embodiments provides significantly better filter delta pressure in
Cummins M11 EGR test in contrast to a 15W40 Blend 2 containing
essentially a non-dispersant VII, which gives poor filter delta
pressure performance in M11 EGR test (see Table I). Similarly a
15W40 Blend 3 containing a graft copolymer of the embodiments
provides passing filter delta pressure in the Cummins M11 High Soot
Test. A 15W40 blend prepared without the graft copolymer of the
embodiments and containing a different non-dispersant VII B gives
failing filter delta pressure performance. Tables II and III
illustrate the beneficial effects of the graft copolymers of the
embodiments with regard to significantly lowering filter delta
pressure in a heavy-duty diesel engine.
[0085] It is known that hard soot particles cause abrasive wear on
valve trains, rings, and liners. Thick lubricating oil films
containing the graft copolymers described herein can significantly
and surprisingly reduce this abrasive wear. Oils with good M-11
test performances form thick boundary films providing percent film
resistance values of 80 to about 95 after 2000 seconds in the High
Frequency Reciprocating Rig (HFRR) test.
[0086] EGR tests show soot thickening from the present embodiments
superior to that seen in the T-8E test. Lubricating oils containing
the graft copolymers described herein are successfully tested in
cooled EGR engines from Cat, Mack, Cummins, Volvo, and Detroit
Diesel. Lubricating oil films containing the graft copolymers of
the embodiments provide excellent performance in the Mack T-11
test, reduce both high and low temperature thickening, give
superior sludge performance, and give superior wear protection from
soot.
[0087] The oils containing the graft copolymers as taught herein
also have the following advantages when used in cooled EGR engines:
excellent for building film strength and reducing wear; low treat
rate of, for example, 8.5% wt. (.about.9.5% vol.) for 15W-40;
strong sludge suppression performance; provides superior
performance in EGR engines; good shear stability, permanent and
HTHS; excellent dispersancy for soot handling and improved wear
protection; allows for lower additive treat rate; and excellent
used-oil low temperature viscosity properties, relative to the low
temperature viscosity properties of oils not containing the graft
copolymers.
[0088] FIG. 1 illustrates that using a lubricating oil containing
the graft copolymer described herein in a cooled EGR engine, the
oil exhibits a kinematic viscosity at 100.degree. C. that does not
increase rapidly in high soot loading, whereas the kinematic
viscosity of the industry standard reference oil increases rapidly
beyond the 4% soot loading level. FIG. 1 shows viscosities for
lubricating oils using Group I and Group II base oils.
[0089] Other embodiments of the present invention will be apparent
to those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. It is intended that
the specification and examples be considered as exemplary only,
with a true scope and spirit of the invention being indicated by
the following claims. This invention is susceptible to considerable
variation in its practice. Accordingly, this invention is not
limited to the specific exemplifications set forth hereinabove.
Rather, this invention is within the spirit and scope of the
appended claims, including the equivalents thereof available as a
matter of law.
[0090] The patentee does not intend to dedicate any disclosed
embodiments to the public, and to the extent any disclosed
modifications or alterations may not literally fall within the
scope of the claims, they are considered to be part of the
invention under the doctrine of equivalents.
* * * * *