U.S. patent application number 13/511469 was filed with the patent office on 2012-12-27 for lubricating composition containing viscosity modifier combination.
This patent application is currently assigned to THE LUBRIZOL CORPORATION. Invention is credited to Gareth Brown, Simon Evans, Andrew Gelder, David Price.
Application Number | 20120329694 13/511469 |
Document ID | / |
Family ID | 43513612 |
Filed Date | 2012-12-27 |
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United States Patent
Application |
20120329694 |
Kind Code |
A1 |
Gelder; Andrew ; et
al. |
December 27, 2012 |
Lubricating Composition Containing Viscosity Modifier
Combination
Abstract
The present invention relates to a lubricating composition
containing (a) an oil of lubricating viscosity, (b) a star polymer
and (c) a substantially linear polymer with a weight average
molecular weight of 45,000 or less. The invention further provides
a method of lubricating a mechanical device, typically a manual
transmission with the lubricating composition. The invention
further provides for the use of the lubricating composition to
provide a number of benefits including lower operating temperatures
and fuel economy
Inventors: |
Gelder; Andrew; (Belper,
GB) ; Price; David; (Littleover, GB) ; Brown;
Gareth; (Belper, GB) ; Evans; Simon; (Derby,
GB) |
Assignee: |
THE LUBRIZOL CORPORATION
Wickliffe
OH
|
Family ID: |
43513612 |
Appl. No.: |
13/511469 |
Filed: |
November 23, 2010 |
PCT Filed: |
November 23, 2010 |
PCT NO: |
PCT/US10/57709 |
371 Date: |
September 10, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61263937 |
Nov 24, 2009 |
|
|
|
Current U.S.
Class: |
508/468 |
Current CPC
Class: |
C10N 2040/04 20130101;
C10M 2205/028 20130101; C10N 2030/06 20130101; C10M 119/24
20130101; C10M 119/12 20130101; C10N 2040/042 20200501; C10M
159/005 20130101; C10N 2020/073 20200501; C10M 145/14 20130101;
C10M 2203/1006 20130101; C10N 2020/04 20130101; C10N 2030/68
20200501; C10M 2209/084 20130101; C10N 2030/02 20130101; C10M
2205/028 20130101; C10M 2209/084 20130101 |
Class at
Publication: |
508/468 |
International
Class: |
C10M 145/14 20060101
C10M145/14; C10M 145/16 20060101 C10M145/16 |
Claims
1-22. (canceled)
23. A lubricating composition comprising (a) an oil of lubricating
viscosity, (b) a star polymer, and (c) a substantially linear
polymer with a weight average molecular weight of 45,000 or less,
wherein the substantially linear polymer is a copolymer comprising
units derived from monomers (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
esterified with an alcohol.
24. The lubricating composition of claim 23, wherein the
substantially linear polymer has a weight average molecular weight
of 8000 to 25,000.
25. The lubricating composition of claim 23, wherein the
substantially linear polymer has a weight average molecular weight
of 12,000 to 20,000.
26. The lubricating composition of claim 23, wherein the
substantially linear polymer is a copolymer derived from monomers
(i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof, wherein 0.1 to 99.89
percent of the carboxylic acid units are esterified with a primary
alcohol branched at the .beta.- or higher position, wherein 0.1 to
99.89 percent of the carboxylic acid units are esterified with a
linear alcohol or an alpha-branched alcohol, wherein 0.01 to 10% of
the carboxylic acid units has at least one of an amino-, amido-
and/or imido-group, and wherein the copolymer has a reduced
specific viscosity of up to 0.08.
27. The lubricating composition of claim 23, wherein the
substantially linear polymer is a copolymer comprising units
derived from monomers (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
esterified with a primary alcohol branched at the .beta.- or higher
position, wherein the copolymer, prior to esterification has a
reduced specific viscosity of up to 0.15.
28. The lubricating composition of claim 27, wherein the
substantially linear polymer prior to esterification has a reduced
specific viscosity of 0.02 to 0.07.
29. The lubricating composition of claim 27, wherein the
substantially linear polymer prior to esterification has a reduced
specific viscosity of 0.04 to 0.06.
30. The lubricating composition of claim 23, wherein the
substantially linear polymer is present at 5 wt % to 30 wt % of the
lubricating composition.
31. The lubricating composition of claim 23, wherein the
substantially linear polymer is a copolymer comprising units
derived from monomers (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
esterified with a primary alcohol branched at the .beta.- or higher
position; and wherein the substantially linear polymer is present
at 5 wt % to 30 wt % of the lubricating composition.
32. The lubricating composition of claim 23, wherein the
ethylenically unsaturated carboxylic acid or derivatives thereof is
at least one of maleic anhydride or maleic acid.
33. The lubricating composition of claim 23, wherein the star
polymer is a poly(meth)acrylate, and wherein the star polymer is
derived from a monomer composition comprising: (a) 50 wt % to 100
wt % of an alkyl (meth)acrylate, wherein the alkyl group of the
(meth)acrylate has 10 to 20 carbon atoms, or mixtures thereof; (b)
0 wt % to 40 wt % of an alkyl (meth)acrylate, wherein the alkyl
group of the (meth)acrylate has 1 to 9 carbon atoms, or mixtures
thereof; and (c) 0 wt % to 10 wt % of a nitrogen-containing
monomer.
34. The lubricating composition of claim 23, wherein the star
polymer is a poly(meth)acrylate, and wherein the star polymer is
derived from a monomer composition comprising: (a) 65 wt % to 95 wt
% of an alkyl (meth)acrylate, wherein the alkyl group of the
(meth)acrylate has 12 to 18 carbon atoms, or mixtures thereof; (b)
5 wt % to 30 wt % of an alkyl (meth)acrylate, wherein the alkyl
group of the (meth)acrylate has 1 to 9, carbon atoms, or mixtures
thereof; and (c) 0 wt % to 5 wt % of a nitrogen-containing
monomer.
35. The lubricating composition of claim 23, wherein the star
polymer is a polymethacrylate and is present at 2 wt % to 30 wt %
of the lubricating composition
36. The lubricating composition of claim 23, wherein the star
polymer is a polymethacrylate and present at 5 wt % to 20 wt %, of
the lubricating composition.
37. The lubricating composition of claim 23, wherein the star
polymer is a polymethacrylate and is present at 0.5 to 10 wt % of
the lubricating composition.
38. The lubricating composition of claim 23, wherein the
lubricating composition contains 0.3 wt % to 15 wt % of star
polymer and 1 wt % to 35 wt % of the substantially linear
polymer.
39. The lubricating composition of claim 23, wherein the
lubricating composition contains 0.45 wt % to 5 wt % of star
polymer and 2 wt % to 25 wt % of the substantially linear
polymer.
40. A method of lubricating a mechanical device comprising
supplying to the device the lubricating composition of claim
23.
41. The method of claim 40, wherein the mechanical device is a
manual transmission.
42. The method of claim 40, wherein the mechanical device is an
automatic transmission.
Description
FIELD OF INVENTION
[0001] The present invention relates to a lubricating composition
containing (a) an oil of lubricating viscosity, (b) a star polymer
and (c) a substantially linear polymer with a weight average
molecular weight of 45,000 or less. The invention further provides
a method of lubricating a mechanical device, typically a manual
transmission with the lubricating composition. The invention
further provides for the use of the lubricating composition to
provide a number of benefits including lower operating temperatures
and fuel economy.
BACKGROUND OF THE INVENTION
[0002] Viscosity index improvers are known to be added to
lubricating oil compositions to improve the viscosity index of the
lubricant. Typical viscosity index improvers include polymers of
methacrylates, acrylates, olefins (such as copolymers of
alpha-olefins and maleic anhydride and esterified derivatives
thereof), or maleic anhydride-styrene copolymers, and esterified
derivatives thereof. The viscosity index improvers tend to
incorporate ester functional groups in pendant/grafted/branched
groups. The ester functional groups may be derived from linear
alkyl alcohols with 1 to 40 carbon atoms. Recent attempts have been
made to produce viscosity index improvers from copolymers of
alpha-olefins. However, such viscosity index improvers have poor
shear stability, too high a viscosity at low temperature, poor fuel
economy, and poor non-dispersant cleanliness.
[0003] In addition, lubricants capable of performing at lower
viscosity (m, for instance, driveline devices) typically provide
increased fuel economy (thus improving corporate average fuel
efficiency (CAFE), NEDC (European Driving Cycle), or FTP-75
(Federal Test Procedure), or Japanese test cycle (JC-08)).
Conversely, higher viscosity fluids contribute to elevated gear and
transmission operating temperatures, which are believed to reduce
fuel economy and diminish durability.
[0004] International publication WO 2007/127660 discloses a
lubricating composition containing a star polymer, a
phosphorus-containing compound and an extreme pressure agent.
[0005] International publications WO2006/047398 and WO2006/047393:
WO2006/047398 discloses that the star polymer may be derived from
atom transfer radical polymerisation (ATRP), nitroxide mediated
polymerisation, anionic polymerisation and reversible addition
fragmentation (RAFT). WO2006/047393 discloses lubricating
compositions having linear and star poly(meth)acrylates derived
from RAFT polymerisation.
[0006] International Patent Application PCT/US2009/052028 discloses
a lubricating composition containing a copolymer comprising units
derived from monomers (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
esterified with a primary alcohol branched at the .beta.- or higher
position, wherein the copolymer, prior to esterification has a
reduced specific viscosity of up to 0.08.
[0007] US Patent Application 2008/0085847 discloses a lubricating
oil composition comprising a major amount of oil of lubricating
viscosity, and a viscosity index (VI) improver composition
comprising a first polymer comprising an amorphous ethylene-.alpha.
olefin copolymer or ethylene-.alpha.-olefin-diene terpolymer having
a crystallinity of not greater than about 1.0%; and a second
polymer comprising a star polymer, the arms of which are derived
from diene, and optionally vinyl aromatic hydrocarbon monomer,
wherein the star polymer has a Shear Stability Index (SSI) of from
about 1% to about 35% (30 cycle).
SUMMARY OF THE INVENTION
[0008] The inventors of this invention have discovered that a
lubricating composition, method and use as disclosed herein is
capable of providing at least one of improved oxidative stability,
reduced mechanical device operating temperatures, increased
mechanical device durability, improved shear stability index,
improved viscosity index, improved low temperature viscometrics and
improved high temperature viscometrics.
[0009] In one embodiment the invention provides a lubricating
composition comprising (a) an oil of lubricating viscosity, (b) a
star polymer, and (c) a substantially linear polymer with a weight
average molecular weight of 45,000 or less, or 35,000 or less, or
25,000 or less, or 8000 to 25,000, or 12,000 to 20,000.
[0010] The substantially linear polymer may have a shear stability
index of less than 25 (or 15 or less, or 10 or less, or 0 to 10, or
0 to 5) as measured by procedure described in CEC test CEC-L-45-99
entitled "Viscosity Shear Stability of Transmission Lubricants
(Taper Roller Bearing Rig)" or test method DIN 51350-6-KRL/C.
[0011] In one embodiment the invention provides a lubricating
composition comprising (a) an oil of lubricating viscosity, (b) a
star polymer, and (c) a substantially linear polymethacrylate
polymer with a weight average molecular weight of 45,000 or less,
or 35,000 or less, or 25,000 or less, or 8000 to 25,000, or 12,000
to 20,000.
[0012] In one embodiment the invention provides a lubricating
composition comprising (a) an oil of lubricating viscosity, (b) a
star polymer, and (c) a copolymer comprising units derived from
monomers (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof esterified with
an alcohol.
[0013] In one embodiment the invention provides a lubricating
composition comprising (a) an oil of lubricating viscosity, (b) a
star polymer, and (c) a copolymer comprising units derived from
monomers (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof esterified with
a primary alcohol branched at the .beta.- or higher position,
wherein the copolymer, prior to esterification has a reduced
specific viscosity of up to 0.2, or up to 0.15, or up to 0.10, or
typically up to 0.08.
[0014] In one embodiment the invention provides a lubricating
composition comprising:
[0015] (a) an oil of lubricating viscosity,
[0016] (b) a star polymer, wherein the star polymer may be a
polymethacrylate or polyacrylate (typically a polymethacrylate),
the star polymer may be derived from a monomer composition
comprising: [0017] (i) 50 wt % to 100 wt % (or 65 wt % to 95 wt %)
of an alkyl methacrylate, wherein the alkyl group of the
methacrylate has 10 to 30, or 10 to 20, or 12 to 18, or 12 to 15
carbon atoms; [0018] (ii) 0 wt % to 40 wt % (or 5 wt % to 30 wt %)
of an alkyl methacrylate, wherein the alkyl group of the
methacrylate has 1 to 9, or 1 to 4 carbon atoms (for example
methyl, butyl, or 2-ethylhexyl); and [0019] (iii) 0 wt % to 10 wt %
(or 0 wt % to 5 wt %, or 0.1 to 2 wt %) of a dispersant monomer
(may be referred to as either oxygen-containing compound, or
nitrogen-containing monomer and typically nitrogen-containing
monomer); and
[0020] (c) copolymer comprising units derived from monomers (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with a primary alcohol
branched at the .beta.- or higher position, wherein the copolymer,
prior to esterification has a reduced specific viscosity of up to
0.2, or up to 0.15, or up to 0.10, typically up to 0.08.
[0021] In one embodiment the invention provides a lubricating
composition comprising an oil of lubricating viscosity, a star
polymer and a copolymer comprising units derived from monomers (i)
an .alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with a primary alcohol
branched at the .beta.- or higher position, wherein the copolymer
is an interpolymer, and wherein the interpolymer has a reduced
specific viscosity (prior to esterification) of up to 0.08, or 0.02
to 0.08 (or 0.02 to 0.07, 0.03 to 0.07 or 0.04 to 0.06).
[0022] The copolymer comprising units derived from monomers (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with a primary alcohol
branched at the .beta.- or higher position may be defined in terms
of weight average molecular weight or by RSV. Typically the weight
average molecular weight is measured on the final esterified
copolymer, optionally capped with an amine. The weight average
molecular weight may be 5000 to 35,000 (approximately 0.15 RSV), or
5000 to 20,000, or 13,000 to 18,000.
[0023] The copolymer reduced specific viscosity (RSV) is measured
by 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 1.6 g of the
copolymer in 100 cm.sup.3 of acetone and the viscosity of acetone
at 30.degree. C. A more detailed description of RSV is provided
below. The RSV is determined for the copolymer of an .alpha.-olefin
and (ii) an ethylenically unsaturated carboxylic acid or
derivatives thereof before esterification with the primary alcohol
branched at the .beta.- or higher position.
[0024] In different embodiments the primary alcohol branched at the
.beta.- or higher position may have at least 12 (or at least 16, or
at least 18 or at least 20) carbon atoms. The number of carbon
atoms may range from at least 12 to 60, or at least 16 to 30.
[0025] In one embodiment the invention provides a lubricating
composition comprising an oil of lubricating viscosity, a star
polymer and a copolymer comprising units derived from monomers (i)
an .alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with a primary alcohol
branched at the .beta.- or higher position, wherein the copolymer
may be an interpolymer, and wherein the interpolymer has a reduced
specific viscosity of up to 0.08, or 0.02 to 0.08 (or 0.02 to 0.07,
0.03 to 0.07 or 0.04 to 0.06).
[0026] In one embodiment the copolymer comprising units derived
from monomers (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof esterified with
a primary alcohol branched at the .beta.- or higher position
described above further comprises units from a monomer having at
least one of an ester group and a nitrogen containing group (such
as amino-, amido- and/or imido-group), typically sufficient to
provide 0.01 wt % to 1.5 wt % (or 0.02 wt % to 0.75 wt %, or 0.04
wt % to 0.25 wt %) nitrogen to the copolymer.
[0027] In one embodiment the invention provides for a method of
lubricating a mechanical device comprising supplying to said
mechanical device (typically a driveline device) a lubricating
composition as disclosed herein. In one embodiment the mechanical
device may be a manual transmission.
[0028] In one embodiment the invention provides for the use of a
lubricating composition as described herein to provide a lubricant
(typically a manual transmission lubricant) with at least one (or
at least two, or up to all) of acceptable or improved shear
stability, acceptable or improved viscosity index control,
acceptable or improved low temperature viscosity, acceptable or
improved fuel economy, and acceptable or improved device operating
temperatures. Typically the lubricant may be used in a driveline
device such as a manual transmission.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The present invention provides a lubricating composition,
method and use as disclosed herein.
Star Polymer
[0030] The lubricating composition of the invention contains a star
polymer (or the star polymer may also be referred to as a radial
polymer). The star polymer may be present in the compositions
described herein at 0.1 wt % to 30, or 0.1 wt % to 20 wt %, wt %,
or 2 wt % to 30 wt %, or 5 wt % to 20 wt %, or 8 wt % to 15 wt %.
The star polymer may also be present at 0.2 wt % to 15 wt %, or 0.5
wt % to 10 wt %, or 1 wt % to 8 wt % of the lubricating
composition.
[0031] A detailed description of the star polymer disclosed herein
may also be described in WO 2007/127660 (published on 8 Nov. 2007,
by Baker et al. and assigned to The Lubrizol Corporation),
paragraphs [0021] to [0061]. Baker discloses composition and
methods of preparation of a variety of star polymers.
[0032] In one embodiment the star polymer may be a polymer derived
from greater than 50 wt % or more of a non-diene monomer.
[0033] In different embodiments the star polymer may contain
greater than 50 wt %, or 55 wt % or more, or 70 wt % or more, or 90
wt % or more, or 95 wt % or more, or 100 wt % of a non-diene
monomer (that is to say, non-diene monomer units or units derived
from polymerisation of one of more non-diene monomers). Examples of
diene monomers include 1,3-butadiene or isoprene. In contrast,
examples of a non-diene of the present invention may include
styrene, methacrylates, acrylates, or mixtures thereof. In one
embodiment the star polymer may be a polymer derived from
methacrylates, or mixtures thereof.
[0034] As described hereinafter the molecular weight of the
viscosity modifier has been determined using known methods, such as
GPC analysis using polystyrene standards. Methods for determining
molecular weights of polymers are well known. The methods are
described for instance: (i) P. J. Flory, "Principles of star
polymer Chemistry", Cornell University Press 91953), Chapter VII,
pp 266-315; or (ii) "Macromolecules, an Introduction to star
polymer Science", F. A. Bovey and F. H. Winslow, Editors, Academic
Press (1979), pp 296-312. As used herein the weight average and
number average molecular weights of the polymers of the invention
are obtained by integrating the area under the peak corresponding
to the star polymer of the invention, which is normally the major
high molecular weight peak, excluding peaks associated with
diluents, impurities, uncoupled star polymer chains and other
additives.
[0035] The star polymer may have a weight average molecular weight
of 100,000 to 1,000,000, or 125,000 to 700,000, or 150,000 to
500,000, or 200,000 to 400,000. The weight average molecular weight
of an arm of the star polymer may be in the range of 8,000 to
150,000, or 10,000 to 100,000 or 15,000 to 75,000, or 25,000 to
70,000.
[0036] As used herein the shear stability index (SSI) of the star
polymer may be determined by a 20 hour KRL test (Volkswagen Tapered
Bearing Roller Test). The test procedure is set out in both
CEC-L-45-A-99 or equivalent test method DIN 51350-6-KRL/C.
[0037] The star polymer SSI may be in the range of 0 to 100, or 0
to 80, or 0 to 60, or 0 to 50, 0 to 20, or 0 to 15, or 0 to 10, or
0 to 5. An example of a suitable range for the SSI includes 1 to 5,
or 25 to 65.
[0038] The star polymer may be a homopolymer or a copolymer, that
is, its arms may be homopolymeric or copolymeric. In one embodiment
the star polymer may be a copolymer. The star polymer may be a star
polymer having a random, tapered, di-block, tri-block or
multi-block architecture. Typically the star polymer has random or
tapered architecture.
[0039] The star polymer may have arms that may have a block-arm
architecture, or hetero-arm architecture, or tapered-arm
architecture. Tapered-arm architecture has a variable composition
across the length of a star polymer arm. For example, the tapered
arm may be composed of, at one end, a relatively pure first monomer
and, at the other end, a relatively pure second monomer. The middle
of the arm is more of a gradient composition of the two
monomers.
[0040] The star polymer derived from a block-arm typically contains
one or more star polymer arms derived from two or more monomers in
block structure within the same arm. A more detailed description of
the block-arm is given in Chapter 13 (pp. 333-368) of "Anionic
Polymerization, Principles and Practical Applications" by Henry
Hsieh and Roderic Quirk (Marcel Dekker, Inc, New York, 1996)
(hereinafter referred to as Hsieh et al.).
[0041] The star polymer typically has architecture such that the
arms may be chemically bonded to a core portion. The core portion
may be a polyvalent (meth)acrylic monomer, oligomer, polymer, or
copolymer thereof, or a polyvalent divinyl non-acrylic monomer,
oligomer polymer, or copolymer thereof. In one embodiment the
polyvalent divinyl non-acrylic monomer may be divinyl benzene. In
one embodiment the polyvalent (meth)acrylic monomer may be an
acrylate or methacrylate ester of a polyol or a methacrylamide of a
polyamine, such as an amide of a polyamine, for instance a
methacrylamide or an acrylamide. In different embodiments the
polyvalent (meth)acrylic monomer may be (i) a condensation reaction
product of an acrylic or methacrylic acid with a polyol or (ii) a
condensation reaction product of an acrylic or methacrylic acid
with a polyamine.
[0042] The polyol which may be condensed with the acrylic or
methacrylic acid in one embodiment contains 2 to 20 carbon atoms,
in another embodiment 3 to 15 carbon atoms and in another
embodiment 4 to 12 carbon atoms; and the number of hydroxyl groups
present in one embodiment may be 2 to 10, in another embodiment 2
to 4 and in another embodiment 2. Examples of polyols include
ethylene glycol, poly (ethylene glycols), alkane diols such as
1,6-hexane diol or triols such as trimethylolpropane, oligomerised
trimethylolpropanes such as Boltorn.RTM. materials sold by Perstorp
Polyols. Examples of polyamines include polyalkylenepolyamines such
as ethylenediamine, diethylenetriamine, triethylenetetramine,
tetraethylenepentamine, pentaethylenehexamine, and mixtures
thereof.
[0043] Examples of the polyvalent unsaturated (meth)acrylic monomer
include ethylene glycol diacrylate, ethylene glycol dimethacrylate,
diethylene glycol diacrylate, diethylene glycol dimethacrylate,
glycerol diacrylate, glycerol triacrylate, mannitol hexaacrylate,
4-cyclohexanediol diacrylate, 1,4-benzenediol dimethacrylate,
pentaerythritol tetraacrylate, 1,3-propanediol diacrylate,
1,5-pentanediol dimethacrylate, bis-acrylates and methacrylates of
polyethylene glycols of molecular weight 200-4000,
polycaprolactonediol diacrylate, pentaerythritol triacrylate,
1,1,1-trimethylolpropane triacrylate, pentaerythritol diacrylate,
pentaerythritol triacrylate, pentaerythritol tetraacrylate,
triethylene glycol diacrylate, triethylene glycol dimethacrylate,
1,1,1-trimethylolpropane trimethacrylate, hexamethylenediol
diacrylate or hexamethylenediol dimethacrylate or an alkylene
bis-(meth)acrylamide.
[0044] The star polymer with branched, comb-like, radial or star
architecture may have 2 or more arms, or 5 or more arms, or 7 or
more arms, or 10 or more arms, for instance 12 to 100, or 14 to 50,
or 16 to 40 arms. The star polymer with branched, comb-like, radial
or star architecture may have 120 arms or less, or 80 arms or less,
or 60 arms or less.
[0045] The star polymer may be obtained/obtainable from a
controlled radical polymerisation technique. Examples of a
controlled radical polymerisation technique include RAFT, ATRP or
nitroxide mediated processes. The star polymer may also be
obtained/obtainable from anionic polymerisation processes. In one
embodiment the star polymer may be obtained/obtainable from RAFT,
ATRP or anionic polymerisation process. In one embodiment the star
polymer may be obtained/obtainable from RAFT or ATRP polymerisation
process. In one embodiment the star polymer may be
obtained/obtainable from a RAFT polymerisation process.
[0046] Methods of preparing polymers using ATRP, RAFT or
nitroxide-mediated techniques are disclosed in the example section
of International Publication WO 2006/047398, see examples 1 to
47.
[0047] More detailed descriptions of polymerisation mechanisms and
related chemistry is discussed for nitroxide-mediated
polymerisation (Chapter 10, pages 463 to 522), ATRP (Chapter 11,
pages 523 to 628) and RAFT (Chapter 12, pages 629 to 690) in the
Handbook of Radical Polymerization, edited by Krzysztof
Matyjaszewski and Thomas P. Davis, 2002, published by John Wiley
and Sons Inc (hereinafter referred to as "Matyjaszewski et
al.").
[0048] The discussion of the star polymer mechanism of ATRP
polymerisation is shown on page 524 in reaction scheme 11.1, page
566 reaction scheme 11.4, reaction scheme 11.7 on page 571,
reaction scheme 11.8 on page 572 and reaction scheme 11.9 on page
575 of Matyjaszewski et al. In ATRP polymerisation, groups that may
be transferred by a radical mechanism include halogens (from a
halogen-containing compound) or various ligands. A more detailed
review of groups that may be transferred is described in U.S. Pat.
No. 6,391,996, or paragraphs 61 to 65 of International Publication
WO 2006/047398.
[0049] In RAFT polymerisation, chain transfer agents are important.
A more detailed review of suitable chain transfer agents is found
in paragraphs [0066] to [0071] of International Publication WO
2006/047398. In one embodiment a suitable RAFT chain transfer agent
includes
2-dodecylsulphanylthiocarbonyl-sulphanyl-2-methyl-propionic acid
butyl ester, cumyl dithiobenzoate or mixtures thereof. A discussion
of the star polymer mechanism of RAFT polymerisation is shown on
page 664 to 665 in section 12.4.4 of Matyjaszewski et al.
[0050] When the star polymer is prepared from anionic
polymerisation techniques, initiators include, for example,
hydrocarbyl lithium initiators such as alkyl lithium compounds
(e.g., methyl lithium, n-butyl lithium, sec-butyl lithium),
cycloalkyl lithium compounds (e.g., cyclohexyl lithium and aryl
lithium compounds (e.g., phenyl lithium, 1-methylstyryl lithium,
p-tolyl lithium, naphyl lithium and 1,1-diphenyl-3-methylpentyl
lithium. Also, useful initiators include naphthalene sodium,
1,4-disodio-1,1,4,4-tetraphenylbutane, diphenylmethyl potassium or
diphenylmethyl sodium.
[0051] A more detailed description of process to prepare the star
polymer derived from anionic processes is discussed in
International Patent Application WO 96/23012, page 3, line 11 to
page 5, line 8. Page 7, line 25 to page 10, line 15 of WO 96/23012
further describes methods of preparing polymers by anionic
polymerisation techniques. A detailed description of anionic
polymerisation process is given in Textbook of Star Polymer
Science, edited by Fred W. Billmeyer Jr., Third Edition, 1984,
Chapter 4, pages 88-90.
[0052] The star polymer may comprise at least one of (a) a star
polymer derived from monomers comprising: (i) a vinyl aromatic
monomer; and (ii) a carboxylic monomer (typically maleic anhydride,
maleic acid, (meth)acrylic acid, itaconic anhydride or itaconic
acid) or derivatives thereof; (b) a poly(meth)acrylate; (c) a
functionalised polyolefin; (d) an ethylene vinyl acetate copolymer;
(e) a fumarate copolymer; (f) a copolymer derived from (i) an
.alpha.-olefin and (ii) a carboxylic monomer (typically maleic
anhydride, maleic acid, (meth)acrylic acid, itaconic anhydride or
itaconic acid) or derivatives thereof; or (g) mixtures thereof. In
one embodiment the star polymer with pendant groups comprises a
polymethacrylate or mixtures thereof.
[0053] In one embodiment the star polymer may be a
poly(meth)acrylate (typically a polymethacrylate). The star polymer
may be derived from a monomer composition comprising:
[0054] (a) 50 wt % to 100 wt % (or 65 wt % to 95 wt %) of an alkyl
(meth)acrylate, wherein the alkyl group of the (meth)acrylate has
10 to 30, or 10 to 20, or 12 to 18, or 12 to 15 carbon atoms, or
mixtures thereof;
[0055] (b) 0 wt % to 40 wt % (or 5 wt % to 30 wt %) of an alkyl
(meth)acrylate, wherein the alkyl group of the (meth)acrylate has 1
to 9, or 1 to 4 carbon atoms (for example methyl, butyl, or
2-ethylhexyl), or mixtures thereof; and
[0056] (c) 0 wt % to 10 wt % (or 0 wt % to 5 wt %, or 0.1 to 2 wt
%) of a nitrogen-containing monomer.
[0057] In one embodiment the star polymer may be a
poly(meth)acrylate (typically a polymethacrylate), the star polymer
may be derived from a monomer composition comprising:
[0058] (a) 65 wt % to 95 wt % (or 65 wt % to 94.9 wt %) of an alkyl
(meth)acrylate, wherein the alkyl group of the (meth)acrylate has
10 to 30, or 10 to 20, or 12 to 18, or 12 to 15 carbon atoms, or
mixtures thereof;
[0059] (b) 5 wt % to 30 wt % of an alkyl (meth)acrylate, wherein
the alkyl group of the (meth)acrylate has 1 to 9, or 1 to 4 carbon
atoms (for example methyl, butyl, or 2-ethylhexyl), or mixtures
thereof; and
[0060] (c) 0 wt % to 5 wt % (or 0.1 to 2 wt %) of a
nitrogen-containing monomer.
[0061] The alkyl (meth)acrylate includes, for example, compounds
derived from saturated alcohols, such as methyl(meth)acrylate,
butyl(meth)acrylate, 2-methylpentyl(meth)acrylate,
2-propylheptyl(meth)acrylate, 2-butyloctyl(meth)acrylate,
2-ethylhexyl(meth)acrylate, octyl(meth)acrylate,
nonyl(meth)acrylate, isooctyl(meth)acrylate,
isononyl(meth)acrylate, 2-tert-butylheptyl(meth)acrylate,
3-isopropylheptyl(meth)acrylate, decyl(meth)acrylate,
undecyl(meth)acrylate, 5-methylundecyl(meth)acrylate,
dodecyl(meth)acrylate, 2-methyldodecyl(meth)acrylate,
tridecyl(meth)acrylate, 5-methyltridecyl(meth)acrylate,
tetradecyl(meth)acrylate, pentadecyl(meth)acrylate,
hexadecyl(meth)acrylate, 2-methylhexadecyl(meth)acrylate,
heptadecyl(meth)acrylate, octadecyl(meth)acrylate,
nonadecyl(meth)acrylate, eicosyl(meth)acrylate,
cetyleicosyl(meth)acrylate, stearyleicosyl(meth)acrylate,
docosyl(meth)acrylate and/or eicosyltetratriacontyl(meth)acrylate;
(meth)acrylates derived from unsaturated alcohols, such as
oleyl(meth)acrylate; and cycloalkyl(meth)acrylates, such as
3-vinyl-2-butylcyclohexyl(meth)acrylate or
bornyl(meth)acrylate.
[0062] The alkyl (meth)acrylates with long-chain alcohol-derived
groups may be obtained, for example, by reaction of a (meth)acrylic
acid (by direct esterification) or methyl methacrylate (by
transesterification) with long-chain fatty alcohols, in which
reaction a mixture of esters such as (meth)acrylate with alkyl
groups of various chain lengths is generally obtained. These fatty
alcohols include Oxo Alcohol.RTM. 7911, Oxo Alcohol.RTM. 7900 and
Oxo Alcohol.RTM. 1100 of Monsanto; Alphanol.RTM. 79 of ICI;
Nafol.RTM. 1620, Alfol.RTM. 610 and Alfol.RTM. 810 of Condea (now
Sasol); Epal.RTM. 610 and Epal.RTM. 810 of Ethyl Corporation;
Linevol.RTM.79, Linevol.RTM. 911 and Dobanol.RTM. 25 L of Shell AG;
Lial.RTM. 125 of Condea Augusta, Milan; Dehydad.RTM. and Lorol.RTM.
of Henkel KGaA (now Cognis) as well as Linopol.RTM. 7-11 and
Acropol.RTM. 91 of Ugine Kuhlmann.
[0063] In one embodiment the star polymer may be further
functionalised in the core or the polymeric arms with a
nitrogen-containing monomer. The nitrogen-containing monomer may be
referred to as a dispersant monomer. The nitrogen-containing
monomer may include a vinyl-substituted nitrogen heterocyclic
monomer, a dialkylaminoalkyl (meth)acrylate monomer, a
dialkylaminoalkyl (meth)acrylamide monomer, a
tertiary-(meth)acrylamide monomer or mixtures thereof.
[0064] In one embodiment the core or polymeric arms further
comprise a (meth)acrylamide or a nitrogen containing (meth)acrylate
monomer. Examples of a suitable nitrogen-containing vinyl monomer
include N,N-dimethylacrylamide, N-vinyl carbonamides such as
N-vinyl-formamide, vinyl pyridine, N-vinylacetoamide,
N-vinyl-n-propionamides, N-vinyl hydroxyacetoamide, N-vinyl
imidazole, N-vinyl pyrrolidinone, N-vinyl caprolactam,
dimethylamino ethyl acrylate (DMAEA), dim ethyl amino
ethyl-methacrylate (DMAEMA), dimethyl aminobutylacrylamide,
dimethylamino-propylmethacrylate (DMAPMA),
dimethylamine-propyl-acrylamide,
dimethyl-aminopropylmethacrylamide, dimethylaminoethyl-acrylamide,
or mixtures thereof.
[0065] A dispersant monomer may also be oxygen-containing compound.
The oxygen-containing compound may include hydroxyalkyl
(meth)acrylates such as 3-hydroxypropyl(meth)acrylate,
3,4-dihydroxybutyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate,
2-hydroxypropyl(meth)acrylate,
2,5-dimethyl-1,6-hexanediol(meth)acrylate,
1,10-decanediol(meth)acrylate, carbonyl-containing (meth)acrylates
such as 2-carboxyethyl(meth)acrylate, carboxymethyl(meth)acrylate,
oxazolidinylethyl(meth)acrylate, N-(methacryloyl-oxy)formamide,
acetonyl(meth)acrylate, N-methacryloylmorpholine,
N-methacryloyl-2-pyrrolidinone,
N-(2-methacryloyloxyethyl)-2-pyrrolidinone,
N-(3-methacryloyloxypropyl)-2-pyrrolidinone,
N-(2-methacryloyloxypentadecyl)-2-pyrrolidinone,
N-(3-methacryloyloxyheptadecyl)-2-pyrrolidinone; glycol
di(meth)acrylates such as 1,4-butanediol(meth)acrylate,
2-butoxyethyl(meth)acrylate, 2-ethoxyethoxymethyl(meth)acrylate,
2-ethoxyethyl(meth)acrylate, or mixtures thereof.
[0066] Other examples of suitable non-carbonyl oxygen containing
compounds capable of being incorporated into the copolymer include
(meth)acrylates of ether alcohols, such as
tetrahydrofurfuryl(meth)acrylate,
vinyloxyethoxyethyl(meth)acrylate,
methoxyethoxyethyl(meth)acrylate, 1-butoxypropyl(meth)acrylate,
1-methyl-(2-vinyloxy)ethyl(meth)acrylate,
cyclo-hexyloxymethyl(meth)acrylate,
methoxymethoxyethyl(meth)acrylate, benzyloxymethyl(meth)acrylate,
furfuryl(meth)acrylate, 2-butoxyethyl(meth)acrylate,
2-ethoxyethoxymethyl(meth)acrylate, 2-ethoxyethyl(meth)acrylate,
allyloxymethyl(meth)acrylate, 1-ethoxybutyl(meth)acrylate,
methoxymethyl(meth)acrylate, 1-ethoxyethyl(meth)acrylate,
ethoxymethyl(meth)acrylate and ethoxylated(meth)acrylates which
typically have 1 to 20, or 2 to 8, ethoxy groups, or mixtures
thereof.
Substantially Linear Polymer
[0067] The composition of the invention includes a substantially
linear polymer with a weight average molecular weight of 45,000 or
less, or 35,000 or less, or 25,000 or less, or 8000 to 25,000, or
12,000 to 20,000.
[0068] The substantially linear polymer may be a copolymer
comprising units derived from monomers (i) an .alpha.-olefin and
(ii) an ethylenically unsaturated carboxylic acid or derivatives
thereof esterified with an alcohol. In one embodiment, the
substantially linear polymer may be a copolymer comprising units
derived from monomers (i) one or more alpha olefins and (ii) one or
more alkyl (meth)acrylate esters. The ethylenically unsaturated
carboxylic acid may be esterified with alcohol before or after
polymerisation with the .alpha.-olefin. In one embodiment the
ethylenically unsaturated carboxylic acid may be esterified with
alcohol before polymerisation with the .alpha.-olefin. In one
embodiment the ethylenically unsaturated carboxylic acid may be
esterified with alcohol after polymerisation with the
.alpha.-olefin.
[0069] A commercially available copolymer prepared by
esterification before polymerisation is available from Akzo Nobel
sold under the tradename Ketjenlube.RTM.3700. The alcohol may have
1 to 40, or 1 to 30, or 4 to 20, or 6 to 16 carbon atoms. Examples
of a suitable alcohol include 2-ethylhexanol, 2-butyloctanol,
2-hexyldecanol, 2-octyldodecanol, 2-decyltetradecanol, butanol,
pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol,
dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol,
heptadecanol, octadecanol, eicosanol, or mixtures thereof. A
copolymer of this type is described in more detail in U.S. Pat. No.
4,526,950, or 6,419,714, or 6,573,224, or 6,174,843.
[0070] The ethylenically unsaturated carboxylic acid may be
esterified with alcohol after polymerisation with the
.alpha.-olefin. A copolymer of this type may be a substantially
linear polymer that may in one embodiment be (a) a copolymer
comprising units derived from monomers (i) an .alpha.-olefin and
(ii) an ethylenically unsaturated carboxylic acid or derivatives
thereof esterified with a primary alcohol branched at the .beta.-
or higher position, wherein the copolymer typically has a reduced
specific viscosity of up to 0.2, (b) a poly(meth)acrylate, or
mixtures thereof.
[0071] The substantially linear polymer may be present in the
compositions described herein at 0.1 wt % to 50 wt %, or 2 wt % to
40 wt %, or 5 wt % to 30 wt %, or 8 wt % to 20 wt % of the
lubricating composition. In certain embodiments the lubricating
composition contains 0.3 to 15 wt % of star polymer and 1 to 35 wt
% of substantially linear polymer. In other embodiments, the
lubricating composition contains 0.45 to 5 wt % of star polymer and
2 to 25 wt % of substantially linear polymer.
Linear Poly(meth)acrylate
[0072] In one embodiment the substantially linear polymer includes
a poly(meth)acrylate, or mixtures thereof.
[0073] In one embodiment the substantially linear polymer includes
a poly(meth)acrylate (typically a polymethacrylate) with units
derived from a mixture of alkyl (meth)acrylate ester monomers
containing, (a) 8 to 24, or 12 to 18, or to 15 carbon atoms in the
alcohol-derived portion of the ester group and (b) 6 to 11, or 8 to
11, or 8 carbon atoms in the alcohol-derived portion of the ester
group, and which have 2-(C.sub.1-4 alkyl)-substituents, and
optionally, at least one monomer selected from the group consisting
of (meth)acrylic acid esters containing 1 to 7 carbon atoms in the
alcohol-derived portion of the ester group and which are different
from (meth)acrylic acid esters (a) and (b), vinyl aromatic
compounds (or vinyl aromatic monomers); and nitrogen-containing
vinyl monomers such as those disclosed above; provided that no more
than 60% by weight, or no more than 50% by weight, or no more than
35% by weight of the esters contain not more than 10 carbon atoms
in the alcohol-derived portion of the ester group. The linear
polymer of this type is described in more detail in U.S. Pat. No.
6,124,249, or EP 0 937 769 A1 paragraphs [0019] and [0031] to
[0067]. (The "alcohol-derived portion" refers to the "--OR" portion
of an ester, when written as R'C(.dbd.O)--OR, whether or not it is
actually prepared by reaction with an alcohol.) Optionally, the
linear polymer may further contain a third monomer. The third
monomer may be styrene, or mixtures thereof. The third monomer may
be present in an amount 0% to 25% of the polymer composition, or
from 1% to 15% of the composition, 2% to 10% of the composition, or
even from 1% to 3% of the composition.
[0074] Typically, the mole ratio of esters (a) to esters (b) in the
copolymer ranges from 95:5 to 35:65, or 90:10 to 60:40, or 80:20 to
50:50.
[0075] The esters are usually aliphatic esters, typically alkyl
esters. In one embodiment the ester of (a) may be a C.sub.12-15
alkyl methacrylate and the ester of (b) may be 2-ethylhexyl
methacrylate.
[0076] In one embodiment, the ester groups in ester (a) contain
branched alkyl groups. The ester groups may contain 2 to 65%, or 5
to 60% of the ester groups having branched alkyl groups.
[0077] The C.sub.1-4 alkyl substituents may be methyl, ethyl, and
any isomers of propyl and butyl.
[0078] The weight average molecular weight of the
poly(meth)acrylate may be 45,000 or less, or 35,000 or less, or
25,000 or less, or 8000 to 25,000, or 12,000 to 20,000.
Copolymer of (i) .alpha.-Olefin and (ii) an Ethylenically
Unsaturated Carboxylic Acid or Derivatives Thereof
[0079] In one embodiment the substantially linear polymer includes
a copolymer comprising units derived from monomers (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with a primary alcohol
branched at the .beta.- or higher position, wherein the copolymer
typically has a reduced specific viscosity of up to 0.2, or up to
0.15, or up to 0.10, or up to 0.08. In one embodiment the reduced
specific viscosity may be up to 0.08 (or 0.02 to 0.08 (or 0.02 to
0.07, 0.03 to 0.07 or 0.04 to 0.06).
[0080] A measurement correlating with molecular weight of the
copolymer (or interpolymer such as an alternating copolymer) may be
expressed in terms of the "reduced specific viscosity" of the
copolymer which is a recognised means of expressing the molecular
size of a polymeric substance. As used herein, the reduced specific
viscosity (abbreviated as RSV) is the value typically 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 1.6 g of the polymer in 100 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 1.6 g of the copolymer per 100 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 a copolymer, appears in Paul J. Flory,
Principles of Polymer Chemistry, (1953 Edition) pages 308 et
seq.
[0081] In one embodiment the copolymer may be derived from monomers
(i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof,
[0082] wherein 0.1 to 99.89 percent of the carboxylic acid units
are esterified with a primary alcohol branched at the .beta.- or
higher position,
[0083] wherein 0.1 to 99.89 percent of the carboxylic acid units
are esterified with a linear alcohol or an alpha-branched alcohol
(e.g, a secondary alcohol),
[0084] wherein 0.01 to 10% of the carboxylic acid units has at
least one of an amino-, amido- and/or imido-group, and
[0085] wherein the copolymer has a reduced specific viscosity
(prior to esterification) of up to 0.08.
[0086] In one embodiment the copolymer may be derived from monomers
(i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof,
[0087] wherein 0.1 to 99.89 percent of the carboxylic acid units
are esterified with a primary alcohol branched at the .beta.- or
higher position,
[0088] wherein 0.1 to 99.9 percent of the carboxylic acid units are
esterified with a linear alcohol or an alpha-branched alcohol,
[0089] wherein 0 to 10% of the carboxylic acid units has at least
one of an amino-, amido- and/or imido-group, and
[0090] wherein the copolymer has a reduced specific viscosity of up
to 0.08.
[0091] A linear alcohol may include methanol, ethanol, propanol,
butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol,
undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol,
hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, or
mixtures thereof. In one embodiment the linear alcohol contains 6
to 30, or 8 to 20, or 8 to 15 carbon atoms (typically 8 to 15
carbon atoms).
[0092] The linear alcohol may include commercially available
materials such as Oxo Alcohol.RTM. 7911, Oxo Alcohol.RTM. 7900 and
Oxo Alcohol.RTM. 1100 of Monsanto; Alphanol.RTM. 79 of ICI;
Nafol.RTM. 1620, Alfol.RTM. 610 and Alfol.RTM. 810 of Condea (now
Sasol); Epal.RTM. 610 and Epal.RTM. 810 of Ethyl Corporation (now
Afton); Linevol.RTM. 79, Linevol.RTM. 911 and Dobanol.RTM. 25 L of
Shell AG; Lial.RTM. 125 of Condea Augusta, Milan; Dehydad.RTM. and
Lorol.RTM. of Henkel KGaA (now Cognis) as well as Linopol.RTM. 7-11
and Acropol.RTM. 91 of Ugine Kuhlmann.
[0093] In one embodiment the copolymer may be derived from monomers
(i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof,
[0094] wherein 5 to 15 percent of the carboxylic acid units are
esterified with a primary alcohol branched at the .beta.- or higher
position,
[0095] wherein 0.1 to 95 percent of the carboxylic acid units are
esterified with a linear alcohol or an alpha-branched alcohol,
[0096] wherein 0 to less than 2% of the carboxylic acid units has
at least one of an amino-, amido- and/or imido-group, and
[0097] wherein the copolymer has a reduced specific viscosity of up
to 0.08.
[0098] In one embodiment the copolymer comprises units derived from
monomers (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof esterified with
a primary alcohol branched at the .beta.- or higher position. In
certain embodiments the copolymer may be represented by the formula
below. Ester or other groups with the primary alcohol-derived
moiety branched at the .beta.- or higher position may be
represented within the ( ).sub.w shown in the formula:
##STR00001##
[0099] wherein [0100] Formula (I) may comprise a copolymer backbone
(BB), and one or more pendant groups as shown, wherein BB may be
derived from a copolymer of (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
(typically fumaric acid, maleic anhydride, maleic acid,
(meth)acrylic acid, itaconic anhydride or itaconic acid); [0101] X
may be a functional group which either (i) contains a carbon and at
least one oxygen or nitrogen atom (such as an ester or amide, or
imide linkage), or (ii) is an alkylene group with 1 to 5 carbon
atoms (typically --CH.sub.2--), connecting the copolymer backbone
and a branched hydrocarbyl group contained within ( ).sub.y,
(typically X may be X may be a functional group which either (i)
contains a carbon and at least one oxygen or nitrogen atom); [0102]
w may be the number of pendant groups attached to the copolymer
backbone, which may be in the range of 2 to 2000, or 2 to 500, or 5
to 250; [0103] y may be 0, 1, 2 or 3, provided that in at least 1
mol % of the pendant groups, y is not zero; and with the proviso
that when y is 0, X is bonded to a terminal group in a manner
sufficient to satisfy the valence of X, wherein the terminal group
is selected from hydrogen, alkyl, aryl, a metal (typically
introduced during neutralisation of ester reactions. Suitable
metals include calcium, magnesium, barium, zinc, sodium, potassium
or lithium) or ammonium cation, and mixtures thereof; [0104] p may
be an integer in the range of 1 to 15 (or 1 to 8, or 1 to 4); and
[0105] R' and R'' may independently be linear or branched
hydrocarbyl groups, and the combined total number of carbon atoms
present in R' and R'' may be at least 12 (or at least 16, or at
least 18 or at least 20).
[0106] In different embodiments the copolymer with pendant groups
may contain 0.10% to 100%, or 0.5% to 20%, or 0.75% to 10%,
branched hydrocarbyl groups represented by a group within ( ).sub.y
of the formula above, expressed as a percentage of the total number
of pendant groups. (The pendant groups of formula (1) may also be
used to define the ester groups as defined above by the phrase
"esterified with a primary alcohol branched at the .beta.- or
higher position").
[0107] In different embodiments the functional groups defined by X
on the formula above, may comprise at least one of --CO.sub.2--,
--C(O)N.dbd. or --(CH.sub.2).sub.v--, wherein v is an integer in
the range of 1 to 20, or 1 to 10, or 1 to 2.
[0108] In one embodiment X may be derived from an ethylenically
unsaturated carboxylic acid or derivatives thereof. Examples of a
suitable carboxylic acid or derivatives thereof typically include
maleic anhydride, maleic acid, (meth)acrylic acid, itaconic
anhydride or itaconic acid. In one embodiment the ethylenically
unsaturated carboxylic acid or derivatives thereof may be at least
one of maleic anhydride or maleic acid.
[0109] In one embodiment X is other than an alkylene group,
connecting the copolymer backbone and the branched hydrocarbyl
groups.
[0110] In different embodiments the pendant groups may be
esterified, amidated or imidated functional groups.
[0111] In one embodiment the pendant groups may be derived from
esterified and/or amidated functional groups.
[0112] In one embodiment the copolymer includes esterified pendant
groups. The pendant groups may be derived from Guerbet alcohols.
The Guerbet alcohols may contain 10 to 60, or 12 to 60, or 16 to 40
carbon atoms. In one embodiment the primary alcohol branched at the
.beta.- or higher position described herein may be a Guerbet
alcohol. Methods to prepare Guerbet alcohols are disclosed in U.S.
Pat. No. 4,767,815 (see column 5, line 39 to column 6, line
32).
[0113] Examples of suitable groups for R' and R'' on the formula
defined above include the following:
[0114] 1) alkyl groups containing C.sub.15-16 polymethylene groups,
such as 2-C.sub.1-15 alkyl-hexadecyl groups (e.g. 2-octylhexadecyl)
and 2-alkyl-octadecyl groups (e.g. 2-ethyloctadecyl,
2-tetradecyl-octadecyl and 2-hexadecyloctadecyl);
[0115] 2) alkyl groups containing C.sub.13-14 polymethylene groups,
such as 1-C.sub.1-15 alkyl-tetradecyl groups (e.g.
2-hexyltetradecyl, 2-decyltetradecyl and 2-undecyltridecyl) and
2-C.sub.1-15 alkyl-hexadecyl groups (e.g. 2-ethyl-hexadecyl and
2-dodecylhexadecyl);
[0116] 3) alkyl groups containing C.sub.10-12polymethylene groups,
such as 2-C.sub.1-15 alkyl-dodecyl groups (e.g. 2-octyldodecyl) and
2-C.sub.1-15 alkyl-dodecyl groups (2-hexyldodecyl and
2-octyldodecyl), 2-C.sub.1-15 alkyl-tetradecyl groups (e.g.
2-hexyltetradecyl and 2-decyltetradecyl);
[0117] 4) alkyl groups containing C.sub.6-9polymethylene groups,
such as 2-C.sub.1-15 alkyl-decyl groups (e.g. 2-octyldecyl) and
2,4-di-C.sub.1-15 alkyl-decyl groups (e.g. 2-ethyl-4-butyl-decyl
group);
[0118] 5) alkyl groups containing C.sub.1-5 polymethylene groups,
such as 2-(3-methylhexyl)-7-methyl-decyl and
2-(1,4-dimethylbutyl)-5,7,7-trimethyl-octyl groups; and
[0119] 6) and mixtures of two or more branched alkyl groups, such
as alkyl residues of oxoalcohols corresponding to propylene
oligomers (from hexamer to undecamer), ethylene/propylene (molar
ratio 16:1-1:11) oligomers, iso-butene oligomers (from pentamer to
octamer), C.sub.5-17 .alpha.-olefin oligomers (from dimer to
hexamer).
[0120] The pendant groups may contain a total combined number of
carbon atoms on R' and R'' in the range of 12 to 60, or 14 to 50,
or 16 to 40, or 18 to 40, or 20 to 36.
[0121] Each of R' and R'' may individually contain 5 to 25, or 8 to
32, or 10 to 18 methylene carbon atoms. In one embodiment the
number of carbon atoms on each R' and R'' group may be 10 to
24.
[0122] Examples of suitable primary alcohol branched at the .beta.-
or higher position include 2-ethylhexanol, 2-propyl heptanol,
2-butyloctanol, 2-hexyldecanol, 2-octyldodecanol,
2-decyltetradecanol, or mixtures thereof.
[0123] The ethylenically unsaturated carboxylic acid or derivatives
thereof may be an acid or anhydride or derivatives thereof that may
be wholly esterified, partially esterified or mixtures thereof.
When partially esterified, other functional groups include acids,
salts or mixtures thereof. Suitable salts include alkali metals,
alkaline earth metals or mixtures thereof. The salts include
lithium, sodium, potassium, magnesium, calcium or mixtures thereof.
The unsaturated carboxylic acid or derivatives thereof includes
acrylic acid, methyl acrylate, methacrylic acid, maleic acid or
anhydride, fumaric acid, itaconic acid or anhydride or mixtures
thereof, or substituted equivalents thereof.
[0124] Suitable examples of the ethylenically unsaturated
carboxylic acid or derivatives thereof include itaconic anhydride,
maleic anhydride, methyl maleic anhydride, ethyl maleic anhydride,
dimethyl maleic anhydride or mixtures thereof.
[0125] In one embodiment the ethylenically unsaturated carboxylic
acid or derivatives thereof includes maleic anhydride or
derivatives thereof.
[0126] Examples of an alpha-olefin include 1-decene, 1-undecene,
1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-hepta-decene 1-octadecene, or mixtures thereof. An
example of a useful alpha-olefin is 1-dodecene. The alpha-olefin
may be a branched alpha-olefin, or mixtures thereof. If the
.alpha.-olefin is branched, the number of carbon atoms of the
.alpha.-olefin may range from 4 to 32, or 6 to 20, or 8 to 16.
[0127] In one embodiment the copolymer of the invention further
includes a nitrogen containing group such as those disclosed above.
The nitrogen containing group may be derived from a nitrogen
containing compound capable of being incorporated during
copolymerization. In one embodiment the copolymer of the invention
further includes a nitrogen containing group that may be capable of
reacting with the functionalised copolymer backbone, typically for
capping the copolymer backbone. The capping may result in the
copolymer having ester, amide, imide or amine groups. The nitrogen
group is described in more detail in paragraphs [0069] to [0087] of
PCT Patent Application Number PCT/US09/052,028, filed on Jul. 29,
2009 by Price, Barton, Visger, entitled "Novel Copolymers and
Lubricating Compositions Thereof".
[0128] In one embodiment the copolymer comprises units derived from
monomers (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof may be further
reacted with an amine to additionally provide oxidation control.
Typically, the copolymer with oxidation control contains an
incorporated residue of an amine-containing compound such as
morpholines, pyrrolidinones, imidazolidinones, acetamides,
.beta.-alanine alkyl esters, or mixtures thereof. Examples of
suitable nitrogen-containing compounds include
3-morpholin-4-yl-propylamine, 3-morpholin-4-yl-ethylamine,
.beta.-alanine alkyl esters (typically alkyl esters have 1 to 30,
or 6 to 20 carbon atoms), or mixtures thereof.
[0129] In one embodiment the compounds based on imidazolidinones,
cyclic carbamates or pyrrolidinones may be derived from a compound
of general
##STR00002##
wherein
X=--OH or NH.sub.2;
[0130] Hy'' may be hydrogen, or a hydrocarbyl group (typically
alkyl, or C.sub.1-4-, or C.sub.2-alkyl); Hy may be a hydrocarbylene
group (typically alkylene, or C.sub.1-4-, or C.sub.2-alkylene);
Q=>NH, >NR, >CH.sub.2, >CHR, >CR.sub.2, or --O--
(typically >NH, or >NR) and R may be C.sub.1-4 alkyl.
[0131] In one embodiment the imidazolidinone includes
1-(2-amino-ethyl)-imidazolidin-2-one (may also be called
aminoethylethyleneurea), 1-(3-amino-propyl)-imidazolidin-2-one,
1-(2-hydroxy-ethyl)-imidazolidin-2-one,
1-(3-amino-propyl)-pyrrolidin-2-one,
1-(3-amino-ethyl)-pyrrolidin-2-one, or mixtures thereof.
[0132] In one embodiment the copolymer may be reacted with an
amine-containing compound selected from morpholines,
imidazolidinones, and mixtures thereof.
Oils of Lubricating Viscosity
[0133] The lubricating composition comprises an oil of lubricating
viscosity. Such oils include natural and synthetic oils, oil
derived from hydrocracking, hydrogenation, and hydrofinishing,
unrefined, refined, re-refined oils or mixtures thereof. A more
detailed description of unrefined, refined and re-refined oils is
provided in International Publication WO2008/147704, paragraphs
[0054] to [0056] (a similar disclosure is provided in US Patent
Application 2010/197536, see [0072] to [0073]). A more detailed
description of natural and synthetic lubricating oils is described
in paragraphs [0058] to [0059] respectively of WO2008/147704 (a
similar disclosure is provided in US Patent Application
2010/197536, see [0075] to [0076]). Synthetic oils may also be
produced by Fischer-Tropsch reactions and typically may be
hydroisomerised Fischer-Tropsch hydrocarbons or waxes. In one
embodiment oils may be prepared by a Fischer-Tropsch gas-to-liquid
synthetic procedure as well as other gas-to-liquid oils.
[0134] Oils of lubricating viscosity may also be defined as
specified in April 2008 version of "Appendix E--API Base Oil
Interchangeability Guidelines for Passenger Car Motor Oils and
Diesel Engine Oils", section 1.3 Sub-heading 1.3. "Base Stock
Categories". In one embodiment the oil of lubricating viscosity may
be an API Group II or Group III oil. In one embodiment the oil of
lubricating viscosity may be an API Group III base oil (typically
including hydrocracked/hydroisomerized base oil).
[0135] The amount of the oil of lubricating viscosity present is
typically the balance remaining after subtracting from 100 wt % the
sum of the amount of the compound of the invention and the other
performance additives.
[0136] The lubricating composition may be in the form of a
concentrate and/or a fully formulated lubricant. If the lubricating
composition of the invention (comprising the additives disclosed
herein) 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 of these additives to the oil of lubricating
viscosity and/or to diluent oil include the ranges of 1:99 to 99:1
by weight, or 80:20 to 10:90 by weight.
Other Performance Additives
[0137] Compositions derived from the copolymer and/or lubricating
compositions described herein optionally further includes other
performance additives. The other performance additives comprise at
least one of metal deactivators, detergents, dispersants, viscosity
modifiers, friction modifiers, corrosion inhibitors, dispersant
viscosity modifiers, antiwear agents, extreme pressure agents,
antis cuffing agents, antioxidants, foam inhibitors, demulsifiers,
pour point depressants, seal swelling agents and mixtures thereof.
Typically, fully-formulated lubricating oil will contain one or
more of these performance additives.
Dispersants
[0138] Dispersants are known and include for example an
N-substituted long chain alkenyl succinimide, a Mannich base, or
mixtures thereof. Examples of N-substituted long chain alkenyl
succinimides include polyisobutylene succinimide, wherein the
polyisobutylene from which it is derived has a number average
molecular weight in the range 350 to 5000, or 500 to 3000, or 750
to 1150.
[0139] The dispersants may also be post-treated by conventional
methods by a reaction with any of a variety of agents. Among these
are boron compounds (such as boric acid), urea, thiourea,
dimercaptothiadiazoles, carbon disulphide, aldehydes, ketones,
carboxylic acids such as terephthalic acid, hydrocarbon-substituted
succinic anhydrides, maleic anhydride, nitriles, epoxides, and
phosphorus compounds. In one embodiment the post-treated dispersant
is borated. In one embodiment the post-treated dispersant is
reacted with dimercaptothiadiazoles.
Detergents
[0140] Detergents are known and include neutral or overbased
detergents, i.e., ones prepared by conventional processes known in
the art. Suitable detergent substrates include, phenates, sulphur
containing phenates, sulphonates, salixarates, salicylates,
carboxylic acid, phosphorus acid, alkyl phenol, sulphur coupled
alkyl phenol compounds, or saligenins. In one embodiment the
detergent includes a magnesium or calcium sulphonate, or mixtures
thereof.
Antioxidant
[0141] Antioxidant compounds are known and include sulphurised
olefins, diphenylamines (such as dinonyl diphenylamine), hindered
phenols, molybdenum dithiocarbamates, and mixtures thereof.
Antioxidant compounds may be used alone or in combination.
[0142] The hindered phenol antioxidant often contains a secondary
butyl and/or a tertiary butyl group as a sterically hindering
group. The phenol group is often further substituted with a
hydrocarbyl group and/or a bridging group linking to a second
aromatic group. Examples of suitable hindered phenol antioxidants
include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol,
4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol
or 4-butyl-2,6-di-tert-butylphenol, or
4-dodecyl-2,6-di-tert-butylphenol. In one embodiment the hindered
phenol antioxidant may be an ester and may include, e.g.,
Irganox.TM. L-135 from Ciba. Suitable examples of molybdenum
dithiocarbamates which may be used as an antioxidant include
commercial materials sold under the trade names such as Vanlube
822.TM. and Molyvan.TM. A from R. T. Vanderbilt Co., Ltd., and
Adeka Sakura-Lube.TM. S-100, S-165 and S-600 from Asahi Denka Kogyo
K. K and mixtures thereof.
Viscosity Modifiers
[0143] In addition to the polymers described herein as part of the
invention the lubricating composition may optionally further
contain other known viscosity modifiers. The viscosity modifiers
may be hydrogenated styrene-butadiene rubbers, ethylene-propylene
copolymers, hydrogenated styrene-isoprene polymers, hydrogenated
diene polymers, polyalkyl styrenes, polyolefins, esters of maleic
anhydride-styrene copolymers, or mixtures thereof.
Antiwear Agent
[0144] The lubricating composition optionally further includes at
least one antiwear agent. Examples of suitable antiwear agents
include oil soluble amine salts of phosphorus compounds,
sulphurised olefins, metal dihydrocarbyldithio-phosphates (such as
zinc dialkyldithiophosphates), thiocarbamate-containing compounds,
such as thiocarbamate esters, thiocarbamate amides, thiocarbamic
ethers, alkylene-coupled thiocarbamates, and
bis(S-alkyldithiocarbamyl) disulphides.
[0145] In one embodiment the oil soluble phosphorus amine salt
antiwear agent includes an amine salt of a phosphorus acid ester or
mixtures thereof. The amine salt of a phosphorus acid ester
includes phosphoric acid esters and amine salts thereof
dialkyldithiophosphoric acid esters and amine salts thereof; amine
salts of phosphites; and amine salts of phosphorus-containing
carboxylic esters, ethers, and amides; and mixtures thereof. The
amine salt of a phosphorus acid ester may be used alone or in
combination.
[0146] In one embodiment the oil soluble phosphorus amine salt
includes partial amine salt-partial metal salt compounds or
mixtures thereof. In one embodiment the phosphorus compound further
includes a sulphur atom in the molecule. In one embodiment the
amine salt of the phosphorus compound may be ashless, i.e.,
metal-free (prior to being mixed with other components).
[0147] The amines which may be suitable for use as the amine salt
include primary amines, secondary amines, tertiary amines, and
mixtures thereof. The amines include those with at least one
hydrocarbyl group, or, in certain embodiments, two or three
hydrocarbyl groups. The hydrocarbyl groups may contain 2 to 30
carbon atoms, or in other embodiments 8 to 26, or 10 to 20, or 13
to 19 carbon atoms.
[0148] Primary amines include ethylamine, propylamine, butylamine,
2-ethylhexylamine, octylamine, and dodecylamine, as well as such
fatty amines as n-octylamine, n-decylamine, n-dodecylamine,
n-tetradecylamine, n-hexadecylamine, n-octadecylamine and
oleyamine. Other useful fatty amines include commercially available
fatty amines such as "Armeen.RTM." amines (products available from
Akzo Chemicals, Chicago, Ill.), such as Armeen C, Armeen O, Armeen
O L, Armeen T, Armeen H T, Armeen S and Armeen S D, wherein the
letter designation relates to the fatty group, such as coco, oleyl,
tallow, or stearyl groups.
[0149] Examples of suitable secondary amines include dimethylamine,
diethylamine, dipropylamine, dibutylamine, diamylamine,
dihexylamine, diheptylamine, methylethylamine, ethylbutylamine and
ethylamylamine. The secondary amines may be cyclic amines such as
piperidine, piperazine and morpholine.
[0150] The amine may also be a tertiary-aliphatic primary amine.
The aliphatic group in this case may be an alkyl group containing 2
to 30, or 6 to 26, or 8 to 24 carbon atoms. Tertiary alkyl amines
include monoamines such as tert-butylamine, tert-hexylamine,
1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine,
tertdodecylamine, tert-tetradecylamine, tert-hexadecylamine,
tert-octadecylamine, tert-tetracosanylamine, and
tert-octacosanylamine.
[0151] In one embodiment the phosphorus acid amine salt includes an
amine with C11 to C14 tertiary alkyl primary groups or mixtures
thereof. In one embodiment the phosphorus acid amine salt includes
an amine with C14 to C18 tertiary alkyl primary amines or mixtures
thereof. In one embodiment the phosphorus acid amine salt includes
an amine with C18 to C22 tertiary alkyl primary amines or mixtures
thereof.
[0152] Mixtures of amines may also be used in the invention. In one
embodiment a useful mixture of amines is "Primene.RTM. 81R" and
"Primene.RTM.JMT." Primene.RTM. 81R and Primene.RTM. JMT (both
produced and sold by Rohm & Haas) are mixtures of C11 to C14
tertiary alkyl primary amines and C18 to C22 tertiary alkyl primary
amines respectively.
[0153] In one embodiment oil soluble amine salts of phosphorus
compounds include a sulphur-free amine salt of a
phosphorus-containing compound may be obtained/obtainable by a
process comprising: reacting an amine with either (i) a
hydroxy-substituted di-ester of phosphoric acid, or (ii) a
phosphorylated hydroxy-substituted di- or tri-ester of phosphoric
acid. A more detailed description of compounds of this type is
disclosed in International Application PCT/US08/051,126 (or
equivalent to U.S. application Ser. No. 11/627,405).
[0154] In one embodiment the hydrocarbyl amine salt of an
alkylphosphoric acid ester is the reaction product of a C14 to C18
alkylated phosphoric acid with Primene 81R.TM. (produced and sold
by Rohm & Haas) which is a mixture of C11 to C14 tertiary alkyl
primary amines.
[0155] Examples of hydrocarbyl amine salts of
dialkyldithiophosphoric acid esters include the reaction product(s)
of isopropyl, methyl-amyl (4-methyl-2-pentyl or mixtures thereof),
2-ethylhexyl, heptyl, octyl or nonyl dithiophosphoric acids with
ethylene diamine, morpholine, or Primene 81R.TM., and mixtures
thereof.
[0156] In one embodiment the dithiophosphoric acid may be reacted
with an epoxide or a glycol. This reaction product is further
reacted with a phosphorus acid, anhydride, or lower ester. The
epoxide includes an aliphatic epoxide or a styrene oxide. Examples
of useful epoxides include ethylene oxide, propylene oxide, butene
oxide, octene oxide, dodecene oxide, and styrene oxide. In one
embodiment the epoxide may be propylene oxide. The glycols may be
aliphatic glycols having from 1 to 12, or from 2 to 6, or 2 to 3
carbon atoms. The dithiophosphoric acids, glycols, epoxides,
inorganic phosphorus reagents and methods of reacting the same are
described in U.S. Pat. Nos. 3,197,405 and 3,544,465. The resulting
acids may then be salted with amines. An example of suitable
dithiophosphoric acid is prepared by adding phosphorus pentoxide
(about 64 grams) at 58.degree. C. over a period of 45 minutes to
514 grams of hydroxypropyl O,O-di(4-methyl-2-pentyl)phosphoro
dithioate (prepared by reacting
di(4-methyl-2-pentyl)-phosphorodithioic acid with 1.3 moles of
propylene oxide at 25.degree. C.). The mixture may be heated at
75.degree. C. for 2.5 hours, mixed with a diatomaceous earth and
filtered at 70.degree. C. The filtrate contains 11.8% by weight
phosphorus, 15.2% by weight sulphur, and an acid number of 87
(bromophenol blue).
[0157] The dithiocarbamate-containing compounds may be prepared by
reacting a dithiocarbamate acid or salt with an unsaturated
compound. The dithiocarbamate containing compounds may also be
prepared by simultaneously reacting an amine, carbon disulphide and
an unsaturated compound. Generally, the reaction occurs at a
temperature from 25.degree. C. to 125.degree. C.
[0158] Examples of suitable olefins that may be sulphurised to form
an the sulphurised olefin include propylene, butylene, isobutylene,
pentene, hexane, heptene, octane, nonene, decene, undecene,
dodecene, undecyl, tridecene, tetradecene, pentadecene, hexadecene,
heptadecene, octadecene, octadecenene, nonodecene, eicosene or
mixtures thereof. In one embodiment, hexadecene, heptadecene,
octadecene, octadecenene, nonodecene, eicosene or mixtures thereof
and their dimers, trimers and tetramers are especially useful
olefins. Alternatively, the olefin may be a Diels-Alder adduct of a
diene such as 1,3-butadiene and an unsaturated ester, such as,
butylacrylate.
[0159] Another class of sulphurised olefin includes fatty acids and
their esters. The fatty acids are often obtained from vegetable oil
or animal oil; and typically contain 4 to 22 carbon atoms. Examples
of suitable fatty acids and their esters include triglycerides,
oleic acid, linoleic acid, palmitoleic acid or mixtures thereof.
Often, the fatty acids are obtained from lard oil, tall oil, peanut
oil, soybean oil, cottonseed oil, sunflower seed oil or mixtures
thereof. In one embodiment fatty acids and/or ester are mixed with
olefins.
[0160] In an alternative embodiment, the ashless antiwear agent may
be a monoester of a polyol and an aliphatic carboxylic acid, often
an acid containing 12 to 24 carbon atoms. Often the monoester of a
polyol and an aliphatic carboxylic acid is in the form of a mixture
with a sunflower oil or the like, which may be present in the
friction modifier mixture from 5 to 95, in several embodiments from
10 to 90, or from 20 to 85, or 20 to 80 weight percent of said
mixture. The aliphatic carboxylic acids (especially a
monocarboxylic acid) which form the esters are those acids
typically containing 12 to 24, or from 14 to 20 carbon atoms.
Examples of carboxylic acids include dodecanoic acid, stearic acid,
lauric acid, behenic acid, and oleic acid.
[0161] Polyols include diols, triols, and alcohols with higher
numbers of alcoholic OH groups. Polyhydric alcohols include
ethylene glycols, including di-, tri- and tetraethylene glycols;
propylene glycols, including di-, tri- and tetrapropylene glycols;
glycerol; butane diol; hexane diol; sorbitol; arabitol; mannitol;
sucrose; fructose; glucose; cyclohexane diol; erythritol; and
penta-erythritols, including di- and tripentaerythritol. Often the
polyol is diethylene glycol, triethylene glycol, glycerol,
sorbitol, pentaerythritol or dipentaerythritol.
[0162] The commercially available monoester known as "glycerol
monooleate" is believed to include 60.+-.5 percent by weight of the
chemical species glycerol monooleate, along with 35.+-.5 percent
glycerol dioleate, and less than 5 percent trioleate and oleic
acid. The amounts of the monoesters, described above, are
calculated based on the actual, corrected, amount of polyol
monoester present in any such mixture.
Extreme Pressure Agents
[0163] Extreme Pressure (EP) agents that are soluble in the oil
include sulphur- and chlorosulphur-containing EP agents,
chlorinated hydrocarbon EP agents and phosphorus EP agents.
Examples of such EP agents include chlorinated wax; sulphurised
olefins (such as sulphurised isobutylene), organic sulphides and
polysulphides such as dibenzyldisulphide, bis-(chlorobenzyl)
disulphide, dibutyl tetrasulphide, sulphurised methyl ester of
oleic acid, sulphurised alkylphenol, sulphurised dipentene,
sulphurised terpene, and sulphurised Diels-Alder adducts;
phosphosulphurised hydrocarbons such as the reaction product of
phosphorus sulphide with turpentine or methyl oleate; phosphorus
esters such as the dihydrocarbon and trihydrocarbon phosphites,
e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexyl
phosphite, pentylphenyl phosphite; dipentylphenyl phosphite,
tridecyl phosphite, distearyl phosphite and polypropylene
substituted phenol phosphite; metal thiocarbamates such as zinc
dioctyldithiocarbamate and barium heptylphenol diacid; amine salts
of alkyl and dialkylphosphoric acids or derivatives including, for
example, the amine salt of a reaction product of a
dialkyldithiophosphoric acid with propylene oxide and subsequently
followed by a further reaction with P.sub.2O.sub.5; and mixtures
thereof (as described in U.S. Pat. No. 3,197,405).
[0164] Corrosion inhibitors that may be useful in the compositions
of the invention include fatty amines, octyl octanamide,
condensation products of dodecenyl succinic acid or anhydride and a
fatty acid such as oleic acid with a polyamine.
[0165] Foam inhibitors that may be useful in the compositions of
the invention include copolymers of ethyl acrylate and
2-ethylhexylacrylate and optionally vinyl acetate; demulsifiers
including trialkyl phosphates, polyethylene glycols, polyethylene
oxides, polypropylene oxides and (ethylene oxide-propylene oxide)
polymers.
[0166] Pour point depressants that may be useful in the
compositions of the invention include polyalphaolefins, esters of
maleic anhydride-styrene copolymers, poly(meth)acrylates,
polyacrylates or polyacrylamides.
[0167] Friction modifiers that may be useful in the compositions of
the invention include fatty acid or fatty alkyl derivatives such as
amines, esters, epoxides, fatty imidazolines, condensation products
of carboxylic acids and polyalkylene-polyamines and amine salts of
alkylphosphoric acids. Other friction modifiers include fatty
derivatives of hydroxyl carboxylic acids such as dialkyl tartrates,
alkyl tartrimides, or citrate esters.
INDUSTRIAL APPLICATION
[0168] The method and lubricating composition of the invention may
be suitable for refrigeration lubricants, greases, gear oils, axle
oils, drive shaft oils, traction oils, manual transmission oils,
automatic transmission oils, metal working fluids, hydraulic oils,
or internal combustion engine oils.
[0169] In one embodiment the method and lubricating composition of
the invention may be suitable for at least one of gear oils, axle
oils, drive shaft oils, traction oils, manual transmission oils or
automatic transmission oils. In one embodiment the invention
provides a method of lubricating a manual transmission.
[0170] An automatic transmission includes continuously variable
transmissions (CVT), infinitely variable transmissions (IVT),
toroidal transmissions, continuously slipping torque converter
clutches (CSTCC), stepped automatic transmissions or dual clutch
transmissions (DCT).
[0171] The use (may also be referred to as a method) and copolymer
composition described herein is capable of providing a lubricant
with at least one (or at least two, or all) of acceptable or
improved shear stability, acceptable or improved viscosity index
control, acceptable or improved oxidation control, and acceptable
or improved low temperature viscosity. The copolymer may be
employed as an oil of lubricating viscosity in the presence or
absence of other base oils.
[0172] When the copolymer with pendant groups further includes a
nitrogen containing compound, the copolymer may further have
acceptable/improved dispersancy properties (cleanliness) and
oxidation control.
[0173] The internal combustion engine may be a 2-stroke or 4-stroke
engine. Suitable internal combustion engines include marine diesel
engines, aviation piston engines, low-load diesel engines, and
automobile and truck engines.
[0174] In several embodiments a suitable lubricating composition
includes the copolymer present (on an actives basis) in ranges as
shown in the following table.
TABLE-US-00001 TABLE Embodiments (wt % of lubricant composition) A
B C D Star Polymer 0.1-30 2-30 5-20 8-15 Substantially Linear
0.1-50 2-40 5-30 8-20 Polymer Other Performance 0-15 0.01-15 0.5-10
0.5-10 Additives Oil of Lubricating Viscosity 5-99.8 15-95.99
40-89.5 55-85.5 Embodiments (wt % of lubricant composition) E F G H
Star Polymer 0.1-20 0.2-15 0.5-10 1-8 Substantially Linear 0.1-50
2-40 5-30 8-20 Polymer Other Performance 0-15 0.01-15 0.5-10 0.5-10
Additives Oil of Lubricating Viscosity 5-99.7 15-97.79 40-94
55-90.5
Footnote: The star polymer and the substantially linear polymer are
those described herein as part of the invention.
[0175] The weight percent of the star polymer and the substantially
linear polymer may also be in the following ranges 5 wt % to 20 wt
% of star polymer and 5 wt % to 15 wt % of the substantially linear
polymer of the lubricating composition disclosed herein. The weight
percent of the star polymer and the substantially linear polymer
may also be in the following ranges 8 wt % to 15 wt % of star
polymer and 5 wt % to 10 wt % of the substantially linear polymer
of the lubricating composition disclosed herein.
[0176] The weight ratio of the star polymer to the substantially
linear polymer may also vary from 6:1 to 1:1, or 4:1 to 1.1, or 3:1
to greater than 2:1. A ratio closer to 2:1 may begin to become less
shear stable than ratios greater than 2:1. In other embodiments,
the ratio may be 0.02:1 to 18:1, and in yet other embodiments, the
ratios may be 0.04:1 to 9:1 or 0.1:1 to 4:1 or 0.2:1 to 2:1. 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
[0177] Star Polymers 1 to 13 (SP1 to SP13): Polymers are the same
as those disclosed on page 32, paragraph [0100] of International
Publication WO 2006/047393 (equivalent to US Publication
2009-0118150) respectively, except monomer B (as is shown in Table
9 of WO 2006/047393) is methyl methacrylate.
[0178] Substantially linear polymers 1 to 8 (SLP1 to SLP8) with a
weight average molecular weight of 45,000 or less are disclosed in
International Application PCT/US09/052,028 (filed 29 Jul. 2009 by
Barton et al., now WO2010/014655) respectively; see examples Cpp1
to Cpp8 in paragraphs [0140] and [0141].
[0179] Comparative Example 1 (CE1) is a manual transmission
lubricant based on an API Group III base oil further containing
0.45 wt % of one or more corrosion inhibitors, 0.75 wt % of one or
more antioxidants, 0.68 wt % of one or more antiwear agents, 0.62
wt % of one or more detergents, 1.5 wt % of one or more
dispersants, 1 wt % of one or more pour point depressant, 0.02 wt %
of one or more antifoam agent and 20 wt % of the copolymer of
SLP1.
[0180] Comparative Example 2 (CE2) is manual transmission lubricant
similar to CE1, except it contains 16 wt % of the polymer of
SP11.
[0181] Invention lubricant 1 (INVL1) is a manual transmission
lubricant similar to CE1, except the copolymer of SLP1 is present
at 11 wt % and the polymer of SP13 is present at 10 wt %.
[0182] The manual transmission lubricants are evaluated using the
following test procedures: ASTM D445 (Kinematic Viscosity (KV) at
40.degree. C. and 100.degree. C., ASTM D2983 (Brookfield Viscosity
(BV) are determined at -40.degree. C.), D2270 (Viscosity Index
(VI)), KRL tapered bearing shear stability test (KRL Test), and an
Energy Loss test
[0183] The lubricating compositions are subjected to shear as
determined by KRL tapered bearing shear stability test employing a
4-ball wear test instrument as is used in CEC DIN 51350 Part 6 test
procedure. The instrument is run for 20 hours with a 5000 N load,
at 140.degree. C. and at 1450 rpm. The viscosity data obtained from
the test is described in ASTM method D445.
[0184] Energy loss data and maximum temperature of gearbox are
measured as is described below. A transverse 5-speed gearbox
modified by locking the gear differential in fourth gear. The
gearbox input is driven by an electric motor and the output load
applied by a dynamometer; the size of each should be suitable for
the test profile. The gear box is mounted in a temperature
controlled environment, capable of maintaining a temperature of
-7.degree. C. The gearbox is pre-soaked at -7.degree. C. for at
least 60 minutes. The low power NEDC test cycle is used throughout
the test. The input speed for the NEDC cycle is calculated to match
the correct output/road speed using available tyre diameters and
gear ratios. In a similar manner the applied load is calculated
from the NEDC test cycle using the assumptions of a medium sector
passenger car, tyre diameter, and gear ratios. The output from the
test is the sump temperature and energy absorbed at the end of each
stage. These are measure via a thermocouple in the gearbox sump and
input/output torque transducers. The test is performed in
triplicate. The results reported are the average based on the three
runs. Typically better results are obtained for samples with a
lower temperature at the end of stage 5, and for samples with lower
energy loss values.
[0185] The results obtained for viscometrics evaluations are:
TABLE-US-00002 CE1 CE2 INVL1 D445 at 9.03 8.37 8.48 100.degree. C.
(mm.sup.2/s) D445 at 40.degree. C. 46.2 28.4 33.0 (mm.sup.2/s)
D2983 at 43,400 12,020 14,640 -40.degree. C. (mm.sup.2/s) VI 181
196 251 KRL Test Kinematic Viscosity 8.64 6.08 6.89 at 100.degree.
C. after KRL Shear (mm.sup.2/s) Viscosity Loss After 4.42 27.36
18.94 Shear Test (%)
[0186] The results obtained for energy loss and maximum temperature
(.degree. C.) are:
TABLE-US-00003 CE1 CE2 INVL1 Stage 1 Loss (kJ) 86.3 58.1 54.8 Stage
2 Loss (kJ) 76.8 56.2 51.1 Stage 3 Loss (kJ) 69.8 53.3 48.3 Stage 4
Loss (kJ) 66.6 52.2 47.4 Stage 5 Loss (kJ) 283.7 242.5 221 Total
Energy Loss (kJ) 44.9 38.2 34.4 Stage 1 Maximum Temperature
(.degree. C.) -1.8 -3.9 -4.1 Stage 2 Maximum Temperature (.degree.
C.) 1.2 -2 -2.3 Stage 3 Maximum Temperature (.degree. C.) 3.2 -0.6
-1.1 Stage 4 Maximum Temperature (.degree. C.) 4.5 0.4 -0.1 Stage 5
Maximum Temperature (.degree. C.) 15.2 9.6 8.7
[0187] The results indicate that the example of the invention has
an improved shear stability, has lost less energy and has reduced
operating temperature compared to either of the comparative
examples.
[0188] It is known that some of the materials described above may
interact in the final formulation, so that the components of the
final formulation may be different from those that are initially
added. The products formed thereby, including the products formed
upon employing lubricant composition of the present invention in
its intended use, may not be susceptible of easy description.
Nevertheless, all such modifications and reaction products are
included within the scope of the present invention; the present
invention encompasses lubricant composition prepared by admixing
the components described above.
[0189] 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. However,
the amount of each chemical component is presented exclusive of any
solvent or diluent oil, which may be customarily present in the
commercial material, unless otherwise indicated. It is to be
understood that the upper and lower amount, range, and ratio limits
set forth herein may be independently combined. 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.
[0190] As used herein, the term "(meth)acrylic" and related terms
includes both acrylic and methacrylic groups.
[0191] As used herein, the term "a primary alcohol branched at the
.beta.- or higher position" relates to an alcohol with branching at
the 2-position or a higher position (e.g., 3-, or 4-, or 5-, or 6-,
or 7-position etc.)
[0192] As used herein the number of carbon atoms present in the
ester groups of the polymers of the invention is counted to include
only those carbon atoms of the alcohol-derived portion of the ester
group. Specifically, the number of carbon atoms excludes the
carbonyl carbon of the ester.
[0193] As used herein, the term "hydrocarbyl substituent" or
"hydrocarbyl group" is used in its ordinary sense, which is
well-known to those skilled in the art. Specifically, it refers to
a group having a carbon atom directly attached to the remainder of
the molecule and having predominantly hydrocarbon character.
Examples of hydrocarbyl groups include: hydrocarbon substituents,
including aliphatic, alicyclic, and aromatic substituents;
substituted hydrocarbon substituents, that is, substituents
containing non-hydrocarbon groups which, in the context of this
invention, do not alter the predominantly hydrocarbon nature of the
substituent; and hetero substituents, that is, substituents which
similarly have a predominantly hydrocarbon character but contain
other than carbon in a ring or chain. A more detailed definition of
the term "hydrocarbyl substituent" or "hydrocarbyl group" is
described in paragraphs [0118] to [0119] of International
Publication WO2008147704 (a similar description of hydrocarbyl is
also described in paragraphs [0137] to [0141] of published
application US 2010-0197536.
[0194] While the invention has been explained in relation to its
preferred embodiments, it is to be understood that various
modifications thereof will become apparent to those skilled in the
art upon reading the specification. Therefore, it is to be
understood that the invention disclosed herein is intended to cover
such modifications as fall within the scope of the appended
claims.
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