U.S. patent application number 12/773150 was filed with the patent office on 2010-08-26 for method of viscosity control.
Invention is credited to Lewis D. Breon, Michael P. Gahagan, Simon J. Griffiths, Jayram D. Patel, David Price, Roy Sambuchino, Mark F. Wilkes.
Application Number | 20100212624 12/773150 |
Document ID | / |
Family ID | 36121330 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100212624 |
Kind Code |
A1 |
Breon; Lewis D. ; et
al. |
August 26, 2010 |
Method of Viscosity Control
Abstract
This invention relates to a method of lubricating an internal
combustion engine comprising at least one of a crankcase, a gear
and a wet-clutch, said method comprising supplying to said
crankcase, gear and wet-clutch a lubricating composition
comprising: (a) an oil of lubricating viscosity; and (b) a
viscosity modifier with a number average molecular weight from 1000
to 75,000, wherein the lubricating composition has a SAE viscosity
grade from XW-Y, wherein X is from 0 to 20 and Y is from 20 to 50;
and wherein the lubricating composition has a phosphorus content
from a metal hydrocarbyl dithiophosphate of 0.12 wt % or less.
Inventors: |
Breon; Lewis D.; (Aurora,
OH) ; Patel; Jayram D.; (Eastlake, OH) ;
Sambuchino; Roy; (Erie, PA) ; Wilkes; Mark F.;
(Derby, GB) ; Griffiths; Simon J.; (Derby, GB)
; Price; David; (Littleover, GB) ; Gahagan;
Michael P.; (Derby, GB) |
Correspondence
Address: |
THE LUBRIZOL CORPORATION;ATTN: DOCKET CLERK, PATENT DEPT.
29400 LAKELAND BLVD.
WICKLIFFE
OH
44092
US
|
Family ID: |
36121330 |
Appl. No.: |
12/773150 |
Filed: |
May 4, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11722368 |
Jun 21, 2007 |
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12773150 |
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Current U.S.
Class: |
123/196R |
Current CPC
Class: |
C10N 2040/255 20200501;
F01M 9/02 20130101; C10M 2205/02 20130101; C10M 169/044 20130101;
C10N 2030/42 20200501; C10M 161/00 20130101; C10N 2020/02 20130101;
C10N 2030/68 20200501; C10M 2209/084 20130101; C10N 2040/04
20130101; C10M 149/02 20130101; C10M 145/14 20130101; C10M 2217/02
20130101; C10N 2030/02 20130101; C10M 2205/04 20130101; C10M 143/00
20130101 |
Class at
Publication: |
123/196.R |
International
Class: |
F01M 1/02 20060101
F01M001/02 |
Claims
1. A method of lubricating an internal combustion engine comprising
a crankcase and at least one of a gear and a wet-clutch, said
method comprising supplying to said crankcase and to at least one
of said gear and wet-clutch a lubricating composition comprising:
(a) an oil of lubricating viscosity; and (b) a viscosity modifier
with a number average molecular weight from about 1000 to about
75,000, wherein the lubricating composition has a SAE viscosity
grade from XW-Y, wherein X is from 0 to about 20 and Y is from
about 20 to about 50; and wherein the lubricating composition has a
phosphorus content from a metal hydrocarbyl dithiophosphate of 0.12
wt % or less, wherein the internal combustion engine is a 4-stroke
motorcycle engine.
2. The method of claim 1, wherein the internal combustion engine
has a common oil reservoir supplying the same lubricating
composition to the crankcase and at least one of a gear and a
wet-clutch.
3. The method of claim 1, wherein the lubricating composition is
supplied to the crankcase and to the gear (or multiplicity of
gears).
4. The method of claim 1, wherein the lubricating composition is
supplied to the crankcase and the wet clutch.
5. The method of claim 1, wherein the lubricating composition is
supplied to the crankcase and both the gear (or gears) and the wet
clutch.
6. The method of claim 1, wherein the viscosity modifier includes
at least one of: (a) polyalkenes or a derivative thereof; (b)
polyalphaolefins; (c) alpha-olefin-unsaturated carboxylic reagent
copolymers; (d) poly(meth)acrylates; (e) Esterified interpolymers
derived from the polymerisation of a vinyl aromatic monomer and an
unsaturated carboxylic acid; or (f) mixtures thereof.
7. The method of claim 1, wherein the viscosity modifier has a
number average molecular weight 2000 to 60,000, or 8000 to
40,000.
8. The method of claim 1, wherein the viscosity modifier has a
number average molecular weight from 1000 to 20,000, or from 25,000
to 40,000.
9. The method of claim 1, wherein the viscosity modifier is a
poly(meth)acrylate.
10. The method of claim 9, wherein the viscosity modifier is a
functionalized poly(meth)acrylate.
11. The method of claim 10, wherein the poly(meth)acrylate is
functionalized with a nitrogen containing monomer.
12. The method of claim 1, wherein the viscosity modifier is
present from 0.5 wt % to 95 wt %, or from 1 wt % to 40 wt % of the
lubricating composition.
13. The method of claim 1, wherein the viscosity modifier has a
Shear Stability Index (SSI) as determined by CEC L-45-A-99 of 22 or
less.
14. The method of claim 1, wherein the viscosity modifier has a
Shear Stability Index (SSI) as determined by CEC L-45-A-99 of 4 to
18.
15. A method of lubricating a 4-stroke motorcycle internal
combustion engine comprising a crankcase and at least one of a gear
and a wet-clutch, said method comprising supplying to said
crankcase and to at least one of said gear and wet-clutch a
lubricating composition comprising: (a) an oil of lubricating
viscosity; and (b) a poly(meth)acrylate viscosity modifier with a
number average molecular weight from about 1000 to about 75,000,
wherein the lubricating composition has an SAE viscosity grade from
XW-Y, wherein X is from 0 to about 20 and Y is from about 20 to
about 50; and wherein the lubricating composition has a phosphorus
content from a metal hydrocarbyl dithiophosphate of 0.12 wt % or
less.
Description
FIELD OF INVENTION
[0001] The present invention relates to a method of viscosity
control by lubricating an internal combustion engine comprising at
least one of a crankcase, a gear, and a wet-clutch with a
lubricating composition.
BACKGROUND OF THE INVENTION
[0002] It is well known for lubricating oils to contain a number of
additives used to protect the engine from wear and provide
viscosity control. Common additives for engine lubricating oils
include zinc dialkyldithiophosphate (ZDDP) an antiwear additive. It
is believed that ZDDP antiwear additives protect the engine by
forming a protective film on metal surfaces. Viscosity modifiers
with a number average molecular weight above 100,000 are known in
crankcase applications as viscosity modifiers because they help
control high temperature viscometrics in multi-grade lubricants.
Viscosity modifiers in various applications are known from, e.g.,
U.S. Pat. No. 5,112,509.
[0003] Current and future government legislation regulating exhaust
emissions from internal combustion engines that contain exhaust
treatment devices are requiring a reduction in the phosphorus and
metal content of engine oils used in these engines. This reduction
in the phosphorus and metal content of engine oils is being
implemented because it is thought that they can adversely affect
the performance of exhaust treatment devices.
[0004] However, any reduction in the performance of catalytic
converters caused by phosphorus poisoning tends to result in
increased amounts of greenhouse gases such as nitric oxide and/or
ash formation. Furthermore, reducing the amount of ZDDP will
increase the amount of wear in an engine crankcase.
[0005] In an internal combustion engine with a wet-clutch (e.g. a
4-stroke motorcycle engine) legislation regulating exhaust
emissions affects/restricts the amount of emissions. However, as
the internal combustion engine has a common oil reservoir, the oil
must be suitable for a crankcase application and a gear, a
transmission system or a clutch mechanism which all have higher
operating conditions resulting in a severe wear environment.
Therefore removing antiwear chemistry, such as, a phosphorus
containing compound will tend to increase the amount of wear in the
gear, transmission or clutch. If a conventional crankcase viscosity
modifier (with a number average molecular weight of 100,000 or
more) is employed in combination with reduced amounts of antiwear
chemistry, it is believed that surface film break down due to the
viscosity modifier shear will give rise to increased wear. The
surface film break down is believed to be due to reduction in high
temperature viscosity of a lubricating oil proportional to the rate
of shear of the viscosity modifier.
[0006] It would be advantageous to have a method of viscosity
control for an internal combustion engine with a wet-clutch capable
of imparting at least one of wear control, acceptable fuel economy,
acceptable high temperature viscometrics and increased lubricant
oil service drains. The present invention provides a method of
viscosity control for said internal combustion engine and capable
of imparting at least one of wear control, acceptable fuel economy,
acceptable high temperature viscometrics and increased lubricant
oil service drains.
SUMMARY OF THE INVENTION
[0007] This invention provides a method of lubricating an internal
combustion engine comprising a crankcase and at least one of a gear
and a wet-clutch, said method comprising supplying to said
crankcase and to at least one of the gear and wet-clutch a
lubricating composition comprising: (a) an oil of lubricating
viscosity; and (b) a viscosity modifier with a number average
molecular weight from 1000 to 75,000, wherein the lubricating
composition has a SAE viscosity grade from XW-Y, wherein X is from
0 to 20 and Y is from 20 to 50; and wherein the lubricating
composition has a phosphorus content from a metal hydrocarbyl
dithiophosphate of 0.12 wt % or less.
DETAILED DESCRIPTION OF THE INVENTION
[0008] This invention provides a method of lubricating an internal
combustion engine comprising a crankcase and at least one of a gear
and a wet-clutch, said method comprising supplying to said
crankcase and to at least one of the gear and wet-clutch a
lubricating composition comprising: (a) an oil of lubricating
viscosity; and (b) a viscosity modifier with a number average
molecular weight from 1000 to 75,000, wherein the lubricating
composition has a SAE viscosity grade from XW-Y, wherein X is from
0 to 20 and Y is from 20 to 50; and wherein the lubricating
composition has a phosphorus content from a metal hydrocarbyl
dithiophosphate of 0.12 wt % or less.
[0009] Internal Combustion Engine
[0010] The internal combustion engine of the invention typically
comprises a crankcase, a gear and a wet-clutch. Optionally the
internal combustion engine further comprises a manual or automatic
transmission. In one embodiment the gear is from a gearbox.
[0011] As used herein the term "wet-clutch" is known to a person
skilled in the art as meaning one that contains a clutch plate(s)
that is bathed or sprayed by a lubricant, e.g., that of the
transmission, and the lubricating oil gets between the
plate(s).
[0012] In one embodiment the internal combustion engine has a
common oil reservoir supplying the same lubricating composition to
the crankcase and at least one of a gear and a wet-clutch. In
certain embodiments the lubricating composition is supplied to the
crankcase and to the gear (or multiplicity of gears), or to the
crankcase and the wet clutch, or to the crankcase and both the gear
(or gears) and the wet clutch.
[0013] In one embodiment the internal combustion engine is a
4-stroke engine. In one embodiment the internal combustion engine
is also referred to generically as a small engine.
[0014] The small engine in one embodiment has a power output of
2.24 to 18.64 kW (3 to 25 horsepower (hp)), in another embodiment
2.98 to 4.53 kW (4 to 6 hp) and in another embodiment exhibits 100
or 200 cm.sup.3 displacement. Examples of small engines include
those in home/garden tools such as lawnmowers, hedge trimmers,
chainsaws, snow blowers or roto-tillers.
[0015] In one embodiment the internal combustion engine has a
capacity of up to 3500 cm.sup.3 displacement, in another embodiment
up to 2500 cm.sup.3 displacement and in another embodiment up to
2000 cm.sup.3 displacement. Examples of suitable internal
combustion engines with a capacity up to 2500 cm.sup.3 displacement
include motorcycles, snowmobiles, jet-skis, quad-bikes, or
all-terrain vehicles. In one embodiment the internal combustion
engine is a tractor or other agricultural vehicle such as a
combined harvester.
[0016] In one embodiment the internal combustion engine is not a
tractor or other agricultural vehicle. In another embodiment the
internal combustion engine does not contain a dry-clutch i.e. a
system that separates the engine from the transmission such as a
transmission on an automotive vehicle. In another embodiment the
internal combustion engine is not suitable for use with a diesel
fuel.
[0017] In one embodiment the internal combustion engine is suitable
for motorcycles for example motorcycles with a 4-stroke internal
combustion engine.
Oil of Lubricating Viscosity
[0018] The lubricating composition includes natural or synthetic
oils of lubricating viscosity; oil derived from hydrocracking,
hydrogenation or hydrofinishing; and unrefined, refined and
re-refined oils, and mixtures thereof.
[0019] Natural oils include animal oils, vegetable oils, mineral
oils and mixtures thereof. Synthetic oils include hydrocarbon oils,
silicon-based oils, and liquid esters of phosphorus-containing
acids. Synthetic oils may be produced by Fischer-Tropsch
gas-to-liquid synthetic procedure as well as other gas-to-liquid
oils. In one embodiment the polymer composition of the present
invention is useful when employed in a gas-to-liquid oil. Often
Fischer-Tropsch hydrocarbons or waxes may be hydroisomerised.
[0020] In one embodiment the base oil is a polyalphaolefin (PAO)
including a PAO-2, PAO-4, PAO-5, PAO-6, PAO-7 or PAO-8 (the
numerical value relating to Kinematic Viscosity at 100.degree. C.).
The polyalphaolefin in one embodiment is prepared from dodecene and
in another embodiment from decene. Generally, the polyalphaolefin
suitable as an oil of lubricating viscosity has a less than that of
a PAO-20 or PAO-30 oil, the reason being that a polyalphaolefin
with a viscosity higher than a PAO-30 is typically too viscous for
effective lubrication of an internal combustion engine.
[0021] Oils of lubricating viscosity may also be defined as
specified in the American Petroleum Institute (API) Base Oil
Interchangeability Guidelines. In one embodiment the oil of
lubricating viscosity comprises an API Group I, II, III, IV, V, VI
oil or mixtures thereof, and in another embodiment API Group II,
III, IV oil or mixtures thereof. In another embodiment the oil of
lubricating viscosity is a Group III or IV base oil and in another
embodiment a Group IV base oil. If the oil of lubricating viscosity
is an API Group II, III, IV, V or VI oil there may be up to 40 wt %
and in another embodiment up to a maximum of 5 wt % of the
lubricating oil an API Group I oil present.
[0022] In one embodiment the lubricating composition has a SAE
viscosity grade from XW-Y, wherein X is from 0 to 20 and Y is from
20 to 50.
[0023] In one embodiment X is chosen from 0, 5, 10, 15 or 20.
[0024] In one embodiment Y is chosen from 20, 25, 30, 35, 40, 45 or
50.
[0025] The oil of lubricating viscosity in one embodiment is
present from 2 wt % to 99.5 wt % of the lubricating composition, in
another embodiment from 29 wt % to 98.25 wt % of the lubricating
composition and in another embodiment from 40 wt % to 97 wt % of
the lubricating composition. Examples of suitable amounts of an oil
of lubricating viscosity include 55 wt %, 60 wt %, 65 wt %, 70 wt
%, 75 wt % or 80 wt %.
Viscosity Modifier
[0026] The viscosity modifier of the invention includes at least
one of the following polymers such as: [0027] (a) polyalkenes or
derivative thereof (such as polyisobutene, olefin copolymers such
as ethylene-alpha-olefin copolymers or ethylene-propylene
polymers); [0028] (b) polyalphaolefins (which can be a type of
polyalkene (a)); [0029] (c) alpha-olefin-unsaturated carboxylic
reagent copolymers; [0030] (d) poly(meth)acrylates; [0031] (e)
interpolymers derived from the polymerisation of a vinyl aromatic
monomer and an unsaturated carboxylic acid or derivatives thereof;
and [0032] (f) mixtures thereof.
[0033] The viscosity modifier in one embodiment is present from 0.5
wt % to 95 wt %, in another embodiment 0.75 wt % to 70 wt % and in
another embodiment 1 wt % to 40 wt % of the lubricating
composition. Examples of a suitable amount of viscosity modifier
include 8 wt %, 10 wt %, 12 wt %, 14 wt %, 16 wt %, 18 wt %, 20 wt
%, 22 wt %, 24 wt %, 30 wt %, 35 wt %, or 55 wt %.
[0034] The viscosity modifiers (which may also be dispersant
viscosity modifiers, as further described below) are known in the
art and commercially available from a number of corporations,
including The Lubrizol Corporation, Degussa AG and Rohmax GmbH.
[0035] In one embodiment the viscosity modifier has a Shear
Stability Index (SSI) as determined by CEC L-45-A-99 of 22 or less,
20 or less or 18 or less. In one embodiment the viscosity SSI is 2
or more or 4 or more. Examples of suitable ranges of SSI include 2
to 22 or 4 to 18.
[0036] In one embodiment the viscosity modifier has a number
average molecular weight from 1000 to 75,000, in another embodiment
2000 to 60,000, in another embodiment 6000 to 50,000 and in another
embodiment 8000 to 40,000. In one embodiment the viscosity modifier
has a number average molecular weight from 1000 to 20,000 and in
another embodiment from 25,000 to 40,000. In one embodiment the
dispersant viscosity modifier has a number average molecular weight
that is the same as the ranges given for the viscosity
modifier.
[0037] In one embodiment the viscosity modifier is a dispersant
viscosity modifier. The polymeric dispersant viscosity modifier may
be derived from a functionalised polyolefin, an esterified polymer
derived from: (i) a vinyl aromatic monomer; and (ii) an unsaturated
carboxylic acid or derivatives thereof; or mixtures thereof.
Poly(meth)acrylates
[0038] In one embodiment the viscosity modifier can be a
poly(meth)acrylate with a number average molecular weight of 10,000
to 35,000, 12,000 to 20,000 or 25,000 to 35,000.
[0039] In one embodiment the poly(meth)acrylate viscosity modifier
includes copolymers of (i) a methacrylic acid ester containing 9 to
30 carbons in the ester group, (ii) a methacrylic acid ester
containing 7 to 12 carbons in the ester group wherein the ester
group contains a 2-(C.sub.1-4 alkyl)-substituents and optionally
(iii) at least one monomer selected from the group consisting of a
methacrylic acid ester containing from 2 to 8 carbon atoms in the
ester group and which are different from methacrylic acid esters
used in (i) and (ii) above. A more detailed description of
polymethacrylate viscosity modifiers can be found in U.S. Pat. No.
6,124,249.
[0040] In one embodiment the viscosity modifier is a functionalized
poly(meth)acrylate. The poly(meth)acrylate is functionalized with a
nitrogen containing monomer thus forming a dispersant viscosity
modifier. In one embodiment the nitrogen containing monomer is
incorporated into the poly(meth)acrylate through standard
copolymerization techniques. The nitrogen containing monomer
includes a vinyl substituted nitrogen heterocyclic monomer, a
dialkylaminoalkyl (meth)acrylate monomer, a dialkylamino alkyl
(meth)acrylamide monomer, a tertiary-(meth)acrylamide monomer and
mixtures thereof. The alkyl groups can contain 1 to 8, or from 1 to
3 carbon atoms. In one embodiment, the dispersant viscosity
modifier is a poly(meth)acrylate.
[0041] Useful nitrogen containing monomers include vinyl pyridine,
N-vinyl imidazole, N-vinyl pyrrolidinone, and N-vinyl caprolactam,
dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate,
dimethylaminobutylacrylamide dimethylamine propyl methacrylate,
dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide,
dimethylaminoethylacrylamide, tertiary butyl acrylamide or mixtures
thereof.
[0042] The poly(meth)acrylate polymeric dispersant viscosity
modifier includes a copolymer derived from a (meth)acrylate monomer
containing an alkyl group with 1 to 30 carbon atoms, in another
embodiment 1 to 26 carbon atoms and in another embodiment 1 to 20
carbon atoms. The alkyl group includes mixtures derived from an
alcohol containing 1 to 4 carbon atoms, 8 to 10 carbon atoms, 12 to
14 carbon atoms, 12 to 15 carbon atoms, 16 to 18 carbon atoms or 16
to 20 carbon atoms. Examples of commercially available alcohol
mixtures include the following products sold under the brand names
of Dobanol.TM. 25, Neodol.TM. 25, Lial.TM.125, and Alchem.TM. 125.
In one embodiment the alcohol is a single alcohol, i.e., not a
mixture.
[0043] The (meth)acrylate monomer includes those derived from
natural or synthetic sources. When derived by synthetic sources the
(meth)acrylate monomer may be prepared using known direct
esterification and/or transesterification processes.
[0044] In one embodiment the poly(meth)acrylate polymeric
dispersant viscosity modifier is derived from a methyl
(meth)acrylate monomer and at least one other (meth)acrylate
monomer including an alkyl group with 8 to 20 carbon atoms, in
another embodiment 10 to 18 carbon atoms and in another embodiment
12 to 15 carbon atoms. The methyl (meth)acrylate monomer is in the
range from 1 wt % or more of the poly(meth)acrylate, in another
embodiment in the range from 8 wt % or more of the
poly(meth)acrylate and in another embodiment in the range from 10
wt % or more of the poly(meth)acrylate. Upper limits on the amount
of methyl (meth)acrylate include 40 wt % of the poly(meth)acrylate,
in another embodiment 30 wt % of the poly(meth)acrylate and in
another embodiment 20 wt % of the poly(meth)acrylate.
Polyalphaolefins
[0045] In one embodiment the viscosity modifier can be one or more
polyalphaolefins having a kinematic viscosity at 100.degree. C.
from 40 mm/s (cSt) to 100 mm/s (cSt). In one embodiment a
polyalphaolefin viscosity modifier is PAO-40, PAO-50, PAO-60 or
PAO-80. In one embodiment the polyalphaolefin's number average
molecular weight is from 1400 to 2000. Generally the
polyalphaolefin viscosity modifier is too viscous to be considered
as an oil of lubricating viscosity.
[0046] In one embodiment the olefin copolymers have a number
average molecular weight of 14,500 to 70,000.
Interpolymers
[0047] In one embodiment the viscosity modifier can be a polymeric
dispersant viscosity modifier such as an esterified polymer derived
from monomers comprising: (i) a vinyl aromatic monomer; and (ii) an
unsaturated carboxylic acid or derivatives thereof. The polymer
prior to esterification is generally referred to as an
interpolymer. In one embodiment the esterified polymer is
substantially free of to free of a (meth)acrylate ester. In one
embodiment the interpolymer is a styrene-maleic anhydride
copolymer. In one embodiment the esterified polymer contains a
nitrogen derived from a nitrogen containing compound capable of
reacting with a functionalised polymer backbone to form an amidated
polymer.
[0048] The molecular weight of the interpolymer may also be
expressed in terms of the "reduced specific viscosity" of the
polymer which is a recognized means of expressing the molecular
size of a polymeric substance. As used herein, the reduced specific
viscosity (abbreviated as RSV) is the value obtained in accordance
with the formula RSV=(Relative Viscosity-1)/Concentration, wherein
the relative viscosity is determined by measuring, by means of a
dilution viscometer, the viscosity of a solution of 1 g of the
polymer in 10 cm.sup.3 of acetone and the viscosity of acetone at
30.degree. C. For purpose of computation by the above formula, the
concentration is adjusted to 0.4 g of the interpolymer per 10
cm.sup.3 of acetone. A more detailed discussion of the reduced
specific viscosity, also known as the specific viscosity, as well
as its relationship to the average molecular weight of an
interpolymer, appears in Paul J. Flory, Principles of Polymer
Chemistry, (1953 Edition) pages 308 et seq. In one embodiment the
interpolymer polymer of the invention has a RSV in the range of
0.05 to 2 in another embodiment 0.06 to 1, in another embodiment
0.06 to 0.8 and in another embodiment 0.07 to 0.2. In another
embodiment the RSV is 0.12. In one embodiment the interpolymer
number average molecular weight is 10,000 to 40,000.
[0049] Examples of a vinyl aromatic monomer include styrene (often
referred to as ethenylbenzene), substituted styrene or mixtures
thereof. Substituted styrene monomers include functional groups
such as a hydrocarbyl group, halo-, amino-, alkoxy-, carboxy-,
hydroxy-, sulphonyl- or mixtures thereof. The functional groups
include those located at the ortho, meta or para positions relative
to the vinyl group on the aromatic monomer, the functional groups
are located at the ortho or para position being especially useful.
In one embodiment the functional groups are located at the para
position. Halo-functional groups include chlorine, bromine, iodine
or mixtures thereof. In one embodiment the halo functional group is
chlorine or mixtures thereof. Alkoxy functional groups may contain
1 to 10 carbon atoms, in another embodiment 1 to 8 carbon atoms, in
another embodiment 1 to 6 carbon atoms and in yet another
embodiment 1 to 4 carbon atoms. Alkoxy functional groups containing
1 to 4 carbon atoms is referred to as lower alkoxy styrene.
[0050] The hydrocarbyl group includes ranges from 1 to 30 carbon
atoms, in another embodiment 1 to 20 carbon atoms, in another
embodiment 1 to 15 carbon atoms and in yet another embodiment 1 to
10 carbon atoms. Examples of a suitable hydrocarbyl group on
styrene monomers include alpha-methylstyrene, para-methylstyrene
(often referred to as vinyl toluene), para-tert-butylstyrene,
alpha-ethylstyrene, para-lower alkoxy styrene or mixtures
thereof.
[0051] In one embodiment the alpha-olefin-unsaturated carboxylic
reagent copolymer has a number average molecular weight of 15,000
to 40,000.
Polyalkene or Derivatives Thereof
[0052] In one embodiment, the viscosity modifier is a polyalkene or
derivatives thereof. In one embodiment the polyalkene or derivative
thereof can have a number average molecular weight of 2300 to
25,000. The polyalkene includes homopolymers and interpolymers of
olefins having from 2 to 40, or from 3 to 24, or from 4 to 12
carbon atoms. The olefins may be monoolefins, such as ethylene,
propylene, 1-butene, isobutene, an alpha-olefin, or polyolefinic
monomers, including diolefinic monomers such 1,3-butadiene and
isoprene. The alpha-olefins generally have from 4 to 30, or from 8
to 18 carbon atoms. These olefins are sometimes referred to as
mono-1-olefins or terminal olefins. The alpha-olefins and
isomerized alpha-olefins include 1-octene, 1-nonene, 1-decene,
1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene,
1-eicosene, 1-heneicosene, 1-docosene, and 1-tetracosene.
Commercially available alpha-olefin fractions that can be used
include the C15-18 alpha-olefins, C12-16 alpha-olefins, C14-16
alpha-olefins, C14-18 alpha-olefins, C16-18 alpha-olefins, C16-20
alpha-olefins, C18-24 alpha-olefins, and C22-28 alpha-olefins. The
polyalkenes may be prepared by conventional procedures. The
polyalkenes are described in U.S. Pat. Nos. 3,219,666 and
4,234,435. Examples of polyalkenes include polypropylenes,
polybutylenes, polyisoprene and polybutadienes. In one embodiment,
the polyalkene is a homopolymer, such as a polyisobutene. One
example of a useful polybutene is a polymer where 50% of the
polymer is derived from isobutylene.
[0053] In another embodiment, the viscosity modifier is an
ethylene-alpha-olefin copolymer. Typically, the copolymer is a
random copolymer. The copolymer generally has from 30% to 80%, or
from 50% to 75% by mole of ethylene. The alpha-olefins include
butene, pentene, hexene or one more of the above-described
alpha-olefins. In one embodiment, the alpha-olefin contains from 3
to 20, or from 4 to 12 carbon atoms. In one embodiment, the
ethylene-alpha-olefin copolymers have a number average molecular
weight from 800 to 6000, or from 1500 to 5000, or from 2000 to
4500. Examples of ethylene alpha-olefins copolymers include
ethylene-butene copolymers and ethylene-octene copolymers. Examples
of commercially available copolymers include Lucant.TM. HC 600 and
Lucant.TM. HC 2000 (Mw=25,000), available from Mitsui Petrochemical
Co. Ltd.
[0054] In another embodiment, the viscosity modifier is an ethylene
propylene polymer. These polymers include ethylene propylene
copolymers and ethylene propylene terpolymers. When the ethylene
propylene polymer is an ethylene propylene copolymer (EPM, also
called EPR polymers), it may be formed by copolymerization of
ethylene and propylene under known conditions such as Ziegler-Natta
reaction conditions. In one embodiment the ethylene propylene
copolymer contains units derived from ethylene in an amount from 40
mol % to 70 mol %, or from 50 mol % to 60 mol %, or 55 mol %, the
remainder being derived from propylene.
[0055] In another embodiment, the ethylene propylene polymer is a
terpolymer of ethylene, propylene and a diene monomer. In one
embodiment, the diene is a conjugated diene. The dienes are
disclosed above. The terpolymers are produced under similar
conditions as those of the ethylene propylene copolymers. The
preferred terpolymers contain units derived form ethylene in amount
from 10% to 80%, or from 25% to 85%, or 35% to 60% by mole, and
units derived from propylene in amount from 15% to 70%, or from 30%
to 60% by mole, and units derived from diene third monomer in
amount from 0.5% to 20%, or from 1% to 10%, or 2% to 8% by
mole.
[0056] In one embodiment the polyalkene or derivatives thereof is a
dispersant viscosity modifier. Typically a dispersant viscosity
modifier from polyalkene or derivatives thereof is prepared by the
reaction of (a) a polyalkene; (b) an acylating agent such as maleic
anhydride; and (c) an amine.
[0057] The amine includes a monoamine, a polyamine or mixtures
thereof. The amine includes primary functionality, secondary
functionality or mixtures thereof. The amine includes cyclic,
linear or branched structures, and examples include an
alkylenemonoamine, a heterocyclic monoamine, an alkylenepolyamine,
a heterocyclic polyamine or mixtures thereof. In one embodiment the
amine contains not more than one primary or secondary amino group,
for example N,N-dimethylaminopropylamine.
[0058] In one embodiment the amine may be a hydroxy-substituted
hydrocarbyl amine such as a hydroxyalkyl amine. Examples of a
suitable hydroxy-substituted hydrocarbyl amine include aminoethyl
ethanolamine, aminopropyl ethanolamine, aminobutyl ethanolamine or
mixtures thereof.
[0059] In one embodiment the amine includes compounds that are
represented by the formula:
##STR00001##
wherein
[0060] w is the number of R.sup.1 atoms, including ranges from 4 to
16 atoms, in another embodiment 5 to 12 atoms, and in another
embodiment 5 to 8 atoms;
[0061] y is the number of carbon atoms associated with R.sup.2,
including ranges from 1 to 8, in another embodiment 1 to 6, and in
another embodiment 2 to 5 carbon atoms;
[0062] R.sup.1 is independently an atom including carbon, oxygen,
nitrogen, phosphorus or mixtures thereof;
[0063] R.sup.2 is an alkyl or an alkenyl group with containing y
carbon atoms, especially useful examples of R.sup.2 including
ethyl, propyl or mixtures thereof; and
[0064] R.sup.3 and R.sup.4 are independently hydrogen or a
hydrocarbyl group; in another embodiment at least one is hydrogen,
and in another embodiment both are hydrogen.
[0065] When R.sup.3 or R.sup.4 is a hydrocarbyl group, the number
of carbon atoms present therein is in the range from 1 to 8, in
another embodiment in the range from 1 to 5 and in another
embodiment in the range from 1 to 3. Examples of a hydrocarbyl
group include methyl, ethyl, propyl, butyl, pentyl or mixtures
thereof.
[0066] Formula (I) represents a compound that includes a
mononuclear cyclic structure, a polynuclear cyclic structure or
mixtures thereof. When formula (I) represents a mononuclear
structure, w in one embodiment ranges from 5 to 8 and in another
embodiment 6 to 7. When formula (I) represents a polynuclear cyclic
structure w in one embodiment ranges from 8 to 16 and in another
embodiment 10 to 12. The cyclic ring includes aromatic,
non-aromatic or mixtures thereof, although a non-aromatic ring is
especially useful.
[0067] Suitable cyclic amines include 4-amino diphenyl amine,
4-(3-aminopropyl)morpholine, 4-(2-aminoethyl)morpholine or mixtures
thereof. In one embodiment the cyclic amine is
4-(3-aminopropyl)morpholine or mixtures thereof.
Metal Hydrocarbyl Dithiophosphate
[0068] In one embodiment of the invention the composition further
contains a metal hydrocarbyl dithiophosphate. The amount of the
metal hydrocarbyl dithiophosphate present is enough to provide a
phosphorus content in the lubricating composition from said metal
hydrocarbyl dithiophosphate of 0.12 wt % or less.
[0069] In one embodiment the phosphorus content in the lubricating
composition from a metal hydrocarbyl dithiophosphate is below 0.1
wt %, in another embodiment below 0.085 wt %, in another embodiment
below 0.06 wt % or lower. In one embodiment the lower limit of the
phosphorus content in the lubricating composition from a metal
hydrocarbyl dithiophosphate is 0 ppm or higher, in another
embodiment 50 ppm or higher, in another embodiment 125 ppm or
higher and in another embodiment 200 ppm or higher. Examples of
suitable ranges include 50 ppm to 0.1 wt % or 125 ppm to 0.085 wt
%.
[0070] Examples of a metal hydrocarbyl dithiophosphate include zinc
dihydrocarbyl dithiophosphates (often referred to as ZDDP, ZDP or
ZDTP). In one embodiment the number of carbon atoms of each
hydrocarbyl group is 2 to 30, 3 to 14 or 4 to 10.
[0071] Examples of suitable zinc hydrocarbyl dithiophosphates
compounds may include those with a hydrocarbyl group of octyl,
2-ethylhexyl, methylpentyl-isopropyl. 2-ethylhexyl-isopropyl,
pentyl-isobutyl or mixtures thereof.
Additional Performance Additives
[0072] In one embodiment of the invention the composition
optionally includes at least one additional performance additive.
The additional performance additive includes at least one of metal
deactivators, detergents, dispersants, extreme pressure agents,
antiwear agents, antioxidants, corrosion inhibitors, foam
inhibitors, demulsifiers, pour point depressants, friction
modifiers, seal swelling agents and mixtures thereof. In one
embodiment the additional performance additives may be used alone
or in combination.
[0073] In one embodiment the total combined amount of the other
performance additive compounds present ranges from 0 wt % to 30 wt
%, in another embodiment from 1 wt % to 25 wt % and in another
embodiment 2 wt % to 20 wt % or from 3 wt % to 10 wt % of the
lubricating composition. Although one or more of the other
performance additives may be present, it is common for the other
additional performance additives to be present in different amounts
relative to each other.
[0074] If the present invention is in the form of a concentrate
(which may be combined with additional oil to form, in whole or in
part, a finished lubricant), the ratio of the various additives to
the oil of lubricating viscosity and/or to diluent oil include the
ranges of 80:20 to 10:90 by weight.
[0075] Friction modifiers include fatty amines, esters such as
borated glycerol esters, fatty phosphites, fatty acid amides, fatty
epoxides, borated fatty epoxides, alkoxylated fatty amines, borated
alkoxylated fatty amines, metal salts of fatty acids, fatty
imidazolines, condensation products of carboxylic acids and
polyalkylene-polyamines, amine salts of alkylphosphoric acids,
molybdenum dithiocarbamate or mixtures thereof. Antioxidants
include sulphurised olefins, hindered phenols, diphenylamines.
Detergents include neutral or overbased, Newtonian or
non-Newtonian, basic salts of alkali, alkaline earth and transition
metals with one or more of a phenate, a sulphurised phenate, a
sulphonate, a carboxylic acid, a phosphorus acid, a mono- and/or a
di-thiophosphoric acid, a saligenin, an alkylsalicylate, a
salixarate or mixtures thereof. Dispersants include N-substituted
long chain alkenyl succinimide as well as post-treated versions
thereof. Post-treated dispersants include those further treated by
reaction with materials such as urea, boron, thiourea,
dimercaptothiadiazoles, carbon disulphide, aldehydes, ketones,
carboxylic acids, hydrocarbon-substituted succinic anhydrides,
nitriles, epoxides and phosphorus compounds.
[0076] Antiwear agents include compounds such as metal
thiophosphates, especially zinc dialkyldithiophosphates; phosphoric
acid esters or salt thereof; phosphites; and phosphorus-containing
carboxylic esters, ethers, and amides; antiscuffing agents
including organic sulphides and polysulphides, such as
benzyldisulphide, bis-(chlorobenzyl)disulphide, dibutyl
tetrasulphide, di-tertiary butyl polysulphide,
di-tert-butylsulphide, sulphurised Diels-Alder adducts or alkyl
sulphenyl N'N-dialkyl dithiocarbamates. Extreme pressure (EP)
agents including chlorinated wax, organic sulphides and
polysulphides, such as benzyldisulphide,
bis-(chlorobenzyl)disulphide, dibutyl tetrasulphide, sulphurised
methyl ester of oleic acid, sulphurised alkylphenol, sulphurised
dipentene, sulphurised terpene, and sulphurised Diels-Alder
adducts; phosphosulphurised hydrocarbons, metal thiocarbamates,
such as zinc dioctyldithiocarbamate and barium heptylphenol diacid;
may also be used in the composition of the invention.
[0077] Additional performance additives such as corrosion
inhibitors include octylamine octanoate, condensation products of
dodecenyl succinic acid or anhydride and a fatty acid such as oleic
acid with a polyamine; metal deactivators including derivatives of
benzotriazoles, thiadiazoles such as dimercaptohtiadiazole and its
derivatives, 1,2,4-triazoles, benzimidazoles,
2-alkyldithiobenzimidazoles or 2-alkyldithiobenzothiazoles; foam
inhibitors including copolymers of ethyl acrylate and
2-ethylhexylacrylate and optionally vinyl acetate; demulsifiers
including polyethylene glycols, polyethylene oxides, polypropylene
oxides and (ethylene oxide-propylene oxide) polymers; pour point
depressants including esters of maleic anhydride-styrene,
polymethacrylates, polyacrylates or polyacrylamides; and seal swell
agents including Exxon Necton-37.TM. (FN 1380) and Exxon Mineral
Seal Oil (FN 3200); may also be used in the composition of the
invention.
[0078] The following examples provide an illustration of the
invention. These examples are non exhaustive and are not intended
to limit the scope of the invention.
EXAMPLES
Example 1 and Reference Examples 1-2
[0079] Lubricating compositions are prepared by blending additives
as shown in Table 1 into a 10W-40 lubricant. The lubricating
compositions have a phosphorus content in the lubricating
composition from a metal hydrocarbyl dithiophosphate of less than
0.12 wt %. The compositions prepared are:
TABLE-US-00001 TABLE 1 Number Average Example Polymer Type
Molecular Weight REF1 Commercially available Over 100,000 Olefin
copolymer REF2 Commercially available 84,000 Olefin copolymer EX1
Polymethacrylate 15,000
Viscosity Test
[0080] A viscosity test to determine Shear Stable Index (SSI) is
carried out employing (i) a KRL Rig at 80.degree. C. for 20 hours
and the methodology of CEC L-45-A-99; and (ii) separately an
Orbahn.TM. Rig and the methodology of CEC-14-A-93.sub.--30.
Generally, better results are obtained for examples with lower
percentage reductions in viscosity. Further acceptable results are
obtained when the percentage loss in viscosity is 12% or less. The
results obtained are shown in Table 2.
TABLE-US-00002 TABLE 2 SOT/ EOT % Loss SSI SSI Example ------ --
KRL Rig---- ----/ (Orbahn) REF1 KV.sub.100 14.96 7.94 46.93 76 25
KV.sub.40 98.2 48.50 50.61 -- -- REF2 KV.sub.100 11.86 10.30 13.15
26 0 KV.sub.40 77.39 65.52 15.34 -- -- EX1 KV.sub.100 12.72 11.68
8.18 14 0 KV.sub.40 83.60 75.35 9.87 -- -- Footnote to Table 2, SOT
is defined as Start of Test; and EOT is defined as End of Test and
"--" represents unmeasured values.
[0081] The results indicate that the presence of the viscosity
modifier with a number average molecular weight from 1000 to 75,000
has acceptable shear stability and is suitable for viscosity
control in an internal combustion engine comprising a crankcase and
at least one of a gear and a wet-clutch. Further, the viscosity
modifier is capable of imparting at least one of wear control,
acceptable fuel economy, acceptable high temperature viscometrics
and increased lubricant oil service drains. Furthermore, the
results indicate that a polymer with a low Shear Stability Index of
26 and a number average molecular weight of above 75,000 provides
poor a viscosity control performance.
[0082] In this specification the terms "hydrocarbyl substituent" or
"hydrocarbyl group," as used herein are used in its ordinary sense,
which is well-known to those skilled in the art. Specifically, it
refers to a group primarily composed of carbon and hydrogen atoms
and attached to the remainder of the molecule through a carbon atom
and which does not exclude the presence of other atoms or groups in
a proportion insufficient to detract from the molecule having a
predominantly hydrocarbon character. In general, no more than two,
in one aspect no more than one, non-hydrocarbon substituent will be
present for every ten carbon atoms in the hydrocarbyl group;
typically, there will be no non-hydrocarbon substituents in the
hydrocarbyl group. A more detailed definition of the terms
"hydrocarbyl substituent" or "hydrocarbyl group," is provided in
U.S. Pat. No. 6,583,092.
[0083] As used herein the term poly(meth)acrylate and other generic
stems with (meth)acryl means polymethacrylate, polyacrylate or
other acryl or methacryl moieties.
[0084] Each of the documents referred to above is incorporated
herein by reference. Except in the Examples, or where otherwise
explicitly indicated, all numerical quantities in this description
specifying amounts of materials, reaction conditions, molecular
weights, number of carbon atoms, and the like, are to be understood
as modified by the word "about." Unless otherwise indicated, each
chemical or composition referred to herein should be interpreted as
being a commercial grade material which may contain the isomers,
by-products, derivatives, and other such materials which are
normally understood to be present in the commercial grade. It is to
be understood that the upper and lower amount, range, and ratio
limits set forth herein may be independently combined.
[0085] Similarly, the ranges and amounts for each element of the
invention may be used together with ranges or amounts for any of
the other elements.
* * * * *