U.S. patent application number 12/297468 was filed with the patent office on 2009-12-03 for star polymer lubricating composition.
This patent application is currently assigned to The Lubrizol Corporation. Invention is credited to Marina Baum, Mark C. Davies, Brent R. Dohnar, David Price, Barton J. Schober, Michael R. Sutton, Daniel C. Visger, Mark F. Wilkes.
Application Number | 20090298729 12/297468 |
Document ID | / |
Family ID | 38537881 |
Filed Date | 2009-12-03 |
United States Patent
Application |
20090298729 |
Kind Code |
A1 |
Schober; Barton J. ; et
al. |
December 3, 2009 |
Star Polymer Lubricating Composition
Abstract
The invention provides a lubricating composition containing (a)
0.001 wt % to 15 wt % of a polymer with radial or star
architecture; (b) an overbased detergent; (c) a dispersant; and (d)
an oil of lubricating viscosity. The invention further provides a
method for lubricating a mechanical device with the lubricating
composition.
Inventors: |
Schober; Barton J.; (Perry,
OH) ; Davies; Mark C.; (Derby, GB) ; Sutton;
Michael R.; (Derbyshire, GB) ; Baum; Marina;
(Chagrin Falls, OH) ; Visger; Daniel C.; (Mentor,
OH) ; Price; David; (Derbyshire, GB) ; Dohnar;
Brent R.; (Concord, OH) ; Wilkes; Mark F.;
(Derby, GB) |
Correspondence
Address: |
THE LUBRIZOL CORPORATION;ATTN: DOCKET CLERK, PATENT DEPT.
29400 LAKELAND BLVD.
WICKLIFFE
OH
44092
US
|
Assignee: |
The Lubrizol Corporation
Wickliffe
CH
|
Family ID: |
38537881 |
Appl. No.: |
12/297468 |
Filed: |
April 19, 2007 |
PCT Filed: |
April 19, 2007 |
PCT NO: |
PCT/US07/66945 |
371 Date: |
January 26, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60745425 |
Apr 24, 2006 |
|
|
|
Current U.S.
Class: |
508/287 ;
508/370; 508/469; 508/470 |
Current CPC
Class: |
C10M 2217/00 20130101;
C10M 2215/064 20130101; C10M 2207/26 20130101; C10M 2217/043
20130101; C10N 2020/073 20200501; C10N 2040/08 20130101; C10N
2020/04 20130101; C10N 2040/04 20130101; C10N 2010/12 20130101;
C10M 2209/084 20130101; C10M 2207/028 20130101; C10M 2215/28
20130101; C10M 2219/022 20130101; C10N 2030/52 20200501; C10M
167/00 20130101; C10N 2040/25 20130101; C10M 2223/045 20130101;
C10M 2219/046 20130101; C10M 161/00 20130101 |
Class at
Publication: |
508/287 ;
508/469; 508/470; 508/370 |
International
Class: |
C10M 133/44 20060101
C10M133/44; C10M 145/14 20060101 C10M145/14; C10M 137/10 20060101
C10M137/10 |
Claims
1. A lubricating composition comprising: (a) 0.001 wt % to 15 wt %
of a polymer with radial or star architecture, wherein the polymer
is a polymethacrylate, or mixtures thereof; (b) an overbased
detergent; (c) a dispersant; and (d) an oil of lubricating
viscosity.
2. The lubricating composition of claim 1, wherein the polymer
contains 70 wt % or more of a mono-vinyl monomer.
3. The lubricating composition of claim 1, wherein the polymer has
a weight average molecular weight of 300,000 to 1,000,000.
4. The lubricating composition of claim 1, wherein the polymer is a
copolymer.
5. The lubricating composition of claim 1, wherein the lubricating
composition further comprises a portion of linear polymer
chains.
6. The lubricating composition of claim 1, wherein the polymer
comprises arms with random, tapered, di-block, tri-block, or
multi-block architecture.
7.-8. (canceled)
9. The lubricating composition of claim 1, wherein the polymer is
obtained from RAFT or ATRP polymerisation processes.
10.-12. (canceled)
13. The lubricating composition of claim 1, wherein the
polymethacrylate is derived from a monomer composition comprising:
(a) 50 wt % to 100 wt % of an alkyl methacrylate, wherein the alkyl
group of the methacrylate has 10 to 20 carbon atoms; (b) 0 wt % to
40 wt % of an alkyl methacrylate, wherein the alkyl group of the
methacrylate has 1 to 9 carbon atoms; and (c) 0 wt % to 10 wt % of
a nitrogen containing monomer.
14. The lubricating composition of claim 1, wherein the polymer is
present at 0.01 to 12 wt %, or 0.075 to 8 wt % of the lubricating
composition.
15. (canceled)
16. The lubricating composition of claim 1, wherein the overbased
detergent comprises one or more of salixarates, phenates,
sulphonates, or salicylates.
17.-18. (canceled)
19. The lubricating composition of claim 1, wherein the dispersant
comprises one or more of succinimide dispersants.
20. (canceled)
21. The lubricating composition of claim 1 further comprising an
antiwear agent.
22. The lubricating composition of claim 21, wherein the antiwear
agent comprises a metal dialkyldithiophosphate.
23. The lubricating composition of claim 1 further comprising an
anti-oxidant.
24. The lubricating composition of claim 23, wherein the
antioxidant is selected from the group consisting of sulphurised
olefins, alkylated diphenylamines, hindered phenols, molybdenum
compounds, and mixtures thereof.
25. The lubricating composition of claim 24, wherein the
antioxidant is a molybdenum compound, an alkylated diphenylamine or
a hindered phenol.
26.-29. (canceled)
30. The lubricating composition of claim 1, wherein the lubricating
composition has a (i) a sulphur content of 0.5 wt % or less, (ii) a
phosphorus content of 0.1 wt % or less, and (iii) a sulphated ash
content of 1.5 wt % or less.
31. The lubricating composition of claim 1, wherein the lubricating
composition has a SAE viscosity grade from XW-Y, where X is an
integer from 0 to 20 and Y is an integer from 20 to 50.
32. The lubricating composition of claim 1, wherein the lubricating
composition contains: (b) 0.1 wt % to 15 wt % of an overbased
detergent; (c) 0.1 wt % to 25 wt % of a dispersant; and (e) 45 wt %
to 99.7 wt % of an oil of lubricating viscosity.
33. A method for lubricating an internal combustion engine
comprising supplying to the internal combustion engine a
lubricating composition, wherein the lubricating composition
comprises: (a) 0.001 wt % to 15 wt % of a polymer with radial or
star architecture; (b) an overbased detergent; (c) a dispersant;
and (d) an oil of lubricating viscosity.
Description
FIELD OF INVENTION
[0001] The present invention relates to a lubricating composition
containing a polymer such as a star polymer, an overbased detergent
and a dispersant. The invention further provides a method for
lubricating a mechanical device using the lubricating
composition.
BACKGROUND OF THE INVENTION
[0002] The use of star polymers in lubricating compositions is
known. The star polymers known in lubricating compositions are
summarised in the prior art below.
[0003] International Application WO 04/087850 discloses lubricating
compositions containing block copolymers prepared from RAFT
(Reversible Addition Fragmentation Transfer) or ATRP (Atom Transfer
Radical Polymerisation) polymerisation processes. The polymers have
factional properties. The block copolymer may have di-block,
tri-block, multi-block, comb and/or star architecture. However, no
guidance is given on methods suitable to prepare star copolymers.
Also disclosed are polymers suitable for greases, motor oils,
gearbox oils, turbine oils, hydraulic fluids, pump oils, heat
transfer oils, insulation oils, cutting oils and cylinder oils.
[0004] U.S. patent application Ser. No. 05/038,146 discloses star
polymers derived from (i) a core portion comprising a polyvalent
(meth) acrylic monomer, oligomer or polymer thereof or a polyvalent
divinyl non-acrylic monomer, oligomer or polymer thereof; and (ii)
at least two arms of polymerized alkyl (meth)acrylate ester. The
polymers may be prepared by RAFT, ATRP or nitroxide mediated
techniques.
[0005] International Application WO 96/23012 discloses
star-branched polymers prepared from acrylic or methacrylic
monomers. The polymers have a core or nucleus derived from acrylate
or methacrylate esters of polyols. Further the polymers have
molecular weights and other physical characteristics that make them
useful for lubricating oil compositions. The star-branched polymers
disclosed are prepared by anionic polymerisation techniques.
[0006] The star polymers of EP 979 834 require from 5 to 10 weight
percent of a C16 to C30 alkyl(meth)acrylate and from 5 to 15 weight
percent of butyl methacrylate. A viscosity index improver with a
C16 to C30 alkyl (meth)acrylate monomer present at 5 weight percent
or more has reduced low temperature viscosity performance because
the polymer has a waxy texture.
[0007] U.S. Pat. No. 5,070,131 disclose gear oil compositions
having improved shear stability index essentially consisting of
gear oil, a viscosity index improver comprising a hydrogenated star
polymer comprising at least four arms, the arms comprising, before
hydrogenation, polymerized conjugated diolefin monomer units and
the arms having a number average molecular weight within the range
of 3,000 to 15,000.
[0008] None of the prior art references above disclose fully
formulated lubricating compositions that simultaneously achieve
acceptable viscosity index (VI), oil blend thickening capabilities,
improved fuel economy, good shear stability, crankcase performance,
good low temperature viscosity performance, and low viscosity
modifier treatment level whilst maintaining the appropriate
lubricating performance for a mechanical device, such as an
internal combustion engine.
[0009] In view of the prior art it would be advantageous to have a
lubricating composition containing a polymer that is capable of
providing acceptable viscosity index (VI), oil blend thickening
capabilities, shear stability, good low temperature viscosity
performance, and low viscosity modifier treatment level whilst
maintaining the appropriate lubricating performance for a
mechanical device.
[0010] The present invention provides a lubricating composition
capable of providing acceptable viscosity index (VI), oil blend
thickening capabilities, shear stability, good low temperature
viscosity performance, and low viscosity modifier treatment level
whilst maintaining the appropriate lubricating performance for a
mechanical device.
[0011] The prior art references, specifically WO 96/23012 and U.S.
Pat. No. 5,070,131 employ anionic polymerisation techniques to
prepare the polymer. Anionic polymerisation techniques are believed
to involve complex processes that require systems to be
substantially water-free, acid-free, oxygen-free, dry, clean, and
have non-contaminated vessels. In one particular embodiment it
would be advantageous to have a lubricating composition that does
not require a polymer prepared with complex processes that require
oxygen-free, dry, clean, non-contaminated vessels. In one
embodiment the lubricating composition contains a polymer that does
not require preparation by anionic polymerisation techniques.
[0012] It is also known that in internal combustion engines
polymethacrylate polymers are believed to form deposits and/or
sludge in various engine components for example in pistons.
Therefore it would be advantageous to employ a viscosity modifier
that reduces/prevents deposits and/or sludge in an internal
combustion engine. In one embodiment the present invention provides
a viscosity modifier that capable of at least one of improved fuel
economy, reduced/prevented deposit, soot or sludge formation, and
low temperature performance in an internal combustion engine.
SUMMARY OF THE INVENTION
[0013] In one embodiment the invention provides a lubricating
composition comprising:
[0014] (a) 0.001 wt % to 15 wt % of a polymer with radial or star
architecture;
[0015] (b) an overbased detergent;
[0016] (c) a dispersant; and
[0017] (d) an oil of lubricating viscosity.
[0018] In one embodiment the invention provides a lubricating
composition comprising:
[0019] (a) 0.001 wt % to 15 wt % of a polymer with radial or star
architecture;
[0020] (b) an overbased detergent;
[0021] (c) a dispersant;
[0022] (d) an antiwear agent, such as a metal
dialkyldithiophosphate; and
[0023] (e) an oil of lubricating viscosity.
[0024] In one embodiment the invention provides a lubricating
composition comprising:
[0025] (a) 0.001 wt % to 15 wt % of a polymer with radial or star
architecture;
[0026] (b) 0.1 wt % to 15 wt % of an overbased detergent;
[0027] (c) 0.1 wt % to 25 wt % of a dispersant; and
[0028] (d) 45 wt % to 99.7 wt % of an oil of lubricating
viscosity.
[0029] In one embodiment the invention provides a method for
lubricating a mechanical device comprising a supplying to the
mechanical device a lubricating composition, wherein the mechanical
device comprises at least one of an internal combustion engine, a
hydraulic system, a turbine system, a circulating oil system, or an
industrial oil system a gear, a gearbox or a transmission, and
wherein the lubricating composition comprises:
[0030] (a) 0.001 wt % to 15 wt % of a polymer with radial or star
architecture;
[0031] (b) an overbased detergent;
[0032] (c) a dispersant; and
[0033] (d) an oil of lubricating viscosity.
[0034] In one embodiment the invention provides a method for
lubricating an internal combustion engine comprising a supplying to
the internal combustion engine a lubricating composition, wherein
the lubricating composition comprises:
[0035] (a) 0.001 wt % to 15 wt % of a polymer with radial or star
architecture;
[0036] (b) an overbased detergent;
[0037] (c) a dispersant; and
[0038] (d) an oil of lubricating viscosity.
DETAILED DESCRIPTION OF THE INVENTION
[0039] The present invention provides a lubricating composition and
a method for lubricating a mechanical device as disclosed
above.
Overbased Detergent
[0040] The lubricating composition comprises an overbased
detergent, or mixtures thereof. The overbased detergent includes
phenales (including alkyl phenates and sulphur containing
phenates), sulphonates, salixarates, carboxylates (such as
salicylates), overbased phosphorus acids; alkyl phenols, overbased
sulphur coupled alkyl phenol compounds, or saligenin detergents. In
one embodiment the overbased detergent comprises one or more of
salixarates, phenates, sulphonates, or salicylates. In one
embodiment the overbased detergent is a salicylate. In one
embodiment the overbased detergent is a sulphonate. In one
embodiment the overbased detergent is a phenate. In one embodiment
the overbased detergent is a salixarate.
Acidic Overbasing Agent
[0041] The acidic overbasing agent used to prepare the overbased
detergent may be a liquid, such as formic acid, acetic acid or
nitric acid. Suitable inorganic acidic agents include SO.sub.2,
carbon dioxide, or mixtures thereof. In different embodiments the
acidic overbasing agent is carbon dioxide or acetic acid. In one
embodiment the acidic overbasing agent is a mixture of carbon
dioxide and acetic acid.
[0042] Various overbased detergents and their methods of
preparation are described in greater detail in numerous patent
publications, including WO2004/096957 and references cited therein.
Typically the overbased detergents may be prepared from the
reaction of a metal base, an acidic agent and an organic substrate
(e.g., an alkyl phenol, salicylic acid or alkyl-substituted benzene
sulphonic acid). The metal base typically includes calcium
hydroxide, calcium oxide, calcium carbonate, magnesium oxide,
magnesium hydroxide or magnesium carbonate.
[0043] When the overbased detergent comprises at least one of a
phenate, salixarate or salicylate detergent, the TBN may be 105 to
450, or from 110 to 400, or from 120 to 350.
[0044] When the overbased detergent comprises an overbased
sulphonate, the TBN may be 200 or more to 500, or 350 to 450.
[0045] The overbased detergent is typically salted with an alkali
or alkaline earth metal. The alkali metal includes lithium,
potassium or sodium; and the alkaline earth metal includes calcium
or magnesium. In one embodiment the alkali metal is sodium. In one
embodiment the alkaline earth metal is calcium. In one embodiment
the alkaline earth metal is magnesium.
[0046] In one embodiment the overbased detergent comprises a
salixarate. The salixarate typically has an organic substrate of a
salixarene. The salixarene may be represented by a substantially
linear compound comprising at least one unit of the formulae (I) or
(II):
##STR00001##
each end of the compound having a terminal group of formulae (III)
or (IV):
##STR00002##
such groups being linked by divalent bridging groups, which may be
the same or different for each linkage; wherein f is 1, 2 or 3, in
one aspect 1 or 2; R.sup.1 is a hydrocarbyl group containing 1 to 5
carbon atoms; R.sup.2 is hydroxyl or a hydrocarbyl group; j is 0,
1, or 2; R.sup.3 is hydrogen or a hydrocarbyl group; R.sup.4 is a
hydrocarbyl group or a substituted hydrocarbyl group; g is 1, 2 or
3, provided at least one R.sup.4 group contains 8 or more carbon
atoms; and wherein the compound on average contains at least one of
unit (I) or (III) and at least one of unit (II) or (IV) and the
ratio of the total number of units (I) and (III) to the total
number of units of (II) and (IV) in the composition is about 0.1:1
to about 2:1.
[0047] The U group in formulae (I) and (III) may be located in one
or more positions ortho, meta, or para to the --COOR.sup.3 group.
The U group may be located ortho to the --COOR.sup.3 group. The U
group may comprise an --OH group, in which case formulae (I) and
(III) are derived from 2-hydroxybenzoic acid (often called
salicylic acid), 3-hydroxybenzoic acid, 4-hydroxybenzoic acid or
mixtures thereof. The U group may comprise an --NTH group, in which
case formulae (I) and (III) are derived from 2-aminobenzoic acid
(often called anthranilic acid), 3-aminobenzoic acid,
4-aminobenzoic acid or mixtures thereof.
[0048] The divalent bridging group, which may be the same or
different in each occurrence, includes a methylene bridge such as
--CH.sub.2-- or --CH(R)-- and an ether bridge such as
--CH.sub.2OCH.sub.2-- or --CH(R)OCH(R)-- where R is an alkyl group
having 1 to 5 carbon atoms and where the methylene and ether
bridges are derived from formaldehyde or an aldehyde having 2 to 6
carbon atoms.
[0049] Often the terminal group of formulae (III) or (IV) contains
1 or 2 hydroxymethyl groups ortho to a hydroxy group. In one
embodiment of the invention hydroxymethyl groups are present. In
one embodiment of the invention hydroxymethyl groups are not
present. A more detailed description of salixarene and salixarate
chemistry is disclosed in EP 1 419 226 B1, including methods of
preparation as defined in Examples 1 to 23 (page 11, line 42 to
page 13, line 47).
[0050] In one embodiment the overbased detergent comprises an
overbased sulphonate. The overbased sulphonate typically includes a
hydrocarbyl substituted arene sulphonic acid of an alkali metal,
alkaline earth metal or mixtures thereof. The hydrocarbyl
substituted arene sulphonic acid may be synthetic or natural. The
arene group of the aryl sulphonic acid may be benzene, toluene or
naphthylene. In one embodiment the hydrocarbyl substituted arene
sulphonic acid comprises alkyl substituted benzene sulphonic acid.
In different embodiments the overbased sulphonate may be a sodium
salt of the hydrocarbyl substituted arene sulphonic acid, a calcium
salt of the hydrocarbyl substituted arene sulphonic acid, or a
magnesium salt of the hydrocarbyl substituted arene sulphonic
acid.
[0051] The hydrocarbyl group (typically an alkyl group) may contain
8 to 40or 10 to 36 carbon atoms. In different embodiments the
overbased detergent may be a polypropene benzenesulphonic acid, or
C.sub.16-C.sub.36 alkyl benzenesulphonic acid, or C.sub.16-C.sub.26
alkyl benzenesulphonic acid, or C.sub.10-C.sub.15 alkyl
benzenesulphonic acid.
[0052] In one embodiment the overbased detergent comprises mixtures
of at ieast two substrates. When two or more detergent substrates
are used, the overbased detergent formed may be described as a
complex/hybrid. Typically the complex/hybrid may be prepared by
reacting in the presence of the suspension and acidifying
overbasing agent, alkyl aromatic sulphonic acid at least one alkyl
phenol (such as, alkyl phenol, aldehyde-coupled alkyl phenol,
sulphurised alkyl phenol) and optionally alkyl salicylic acid. A
more detailed description of hybrid detergents is disclosed in
WO97046643.
[0053] The detergent may be present at 0.1 wt % to 10 wt %, or 0.1
wt % to 8 wt %, or 1 wt % to 4 wt %, or greater than 4 to 8 wt
%.
Polymer
[0054] As used herein terms such as "the polymer has (or contains)
monomers or composed of" means the polymer comprises units derived
from the particular monomer referred to.
[0055] In different embodiments the polymer may contain about 20 wt
% or more, or greater than 50 wt %, or about 55 wt % or more, or
about 70 wt % or more, or about 90 wt % or more, or about 95 wt %
or more, or about 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. Examples of a non-diene or mono-vinyl
monomer include styrene, methacrylates, or acrylates.
[0056] In one embodiment the polymer may be derived from 20 wt % or
more of a mono-vinyl monomer, wherein the polymer has a weight
average molecular weight of 100,000 to 1,000,000, or 200,000 to
1,000,000, or 300,000 to 1,000,000, or 350,000 to 1,000,000, or
400,000 to 800,000.
[0057] In one embodiment the polymer may have a shear stability as
measured by ASTM D6278 at 100.degree. C. (or CEC-L-14A-93, except
shear measurements are determined after 30 cycles at 100.degree.
C.). In different embodiments the shear stability is such that the
final lubricating composition (after testing) has a viscosity
decrease of less than 30%, or 20% or less, or 15% or less, or 10%
or less.
[0058] Typically the amount of mono-vinyl monomer as described
above refers only to the composition of the polymeric arms of the
polymer with radial or star architecture, i.e., the wt % values as
given are exclusive of any di-functional (or higher) monomer found
in a polymer core.
[0059] 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 Polymer
Chemistry", Cornell University Press 91953), Chapter VII, pp
266-315; or (ii) "Macromolecules, an Introduction to Polymer
Science", F. A. Bovey and F. II. 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 polymer of the invention, which is normally the major high
molecular weight peak, excluding peaks associated with diluents,
impurities, uncoupled polymer chains and other additives.
Typically, the polymer of the invention has radial or star
architecture.
[0060] The polymer may be a homopolymer or a copolymer. In one
embodiment the polymer is a copolymer. The polymer may be a polymer
having a random, tapered, di-block, tri-block or multi-block
architecture. Typically the polymer has random or tapered
architecture.
[0061] The polymer with radial or star architecture typically has
polymeric arms. For such materials, the polymeric arms may have
block architecture, or hetero architecture, or tapered
architecture. Tapercd-arm architecture has a variable composition
across the length of a 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.
[0062] The polymer derived from a block-arm typically contains one
or more 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.).
[0063] The hetero-arm, or "mikto-arm," polymeric arm architecture
typically contains arms which may vary from one another either in
molecular weight, composition, or both, as defined in Hsieh et ah,
cited above. For example, a portion of the arms of a given polymer
may be of one polymeric type and a portion of a second polymeric
type. More complex hetero-arm polymers may be formed by combining
portions of three or more polymeric arms with a coupling agent.
[0064] The polymer with radial or star architecture typically
contains polymeric arms that 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 is divinyl benzene. In one embodiment the polyvalent
(meth)acrylic monomer is 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 is (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.
[0065] The polyol which may be condensed with the acrylic or
methacrylic acid in different embodiments may contain 2 to 20, or 3
to 15, or 4 to 12 carbon atoms; and the number of hydroxyl groups
present may be 2 to 10, or 2 to 4, or 2. Examples of polyols
include ethylene glycol, poly (ethylene glycols), alkane diols such
as 1,6-hexanene 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, tetraethylene pentamine,
pentaethylenehexamine and mixtures thereof.
[0066] 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 to 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.
[0067] The amount of polyvalent coupling agent may be an amount
suitable to provide coupling of polymer previously prepared as arms
onto a core comprising the coupling agent in monomeric, oligomeric,
or polymeric form, to provide a star polymer. As described above,
suitable amounts may be determined readily by the person skilled in
the art with minimal experimentation, even though several variables
may be involved. For example, if an excessive amount of coupling
agent is employed, or if excessive unreacted monomer from the
formation of the polymeric arms remains in the system, crosslinking
rather than star formation may occur. Typically the mole ratio of
polymer arms to coupling agent may be 50:1 to 1.5:1 (or 1:1), or
30:1 to 2:1, or 10:1 to 3:1, or 7:1 to 4:1, or 4:1 to 1:1. In other
embodiments the mole ratio of polymer arms to coupling agent may be
50:1 to 0.5:1, or 30:1 to 1:1, or 7:1 to 2:1. The desired ratio may
also be adjusted to take into account the length of the arms,
longer arms sometimes tolerating or requiring more coupling agent
than shorter arms. Typically the material prepared is soluble in an
oil of lubricating viscosity.
[0068] In one embodiment the polymeric arms of the polymer have a
polydispersity of 2 or less, or 1.7 or less, or 1.5 or less, for
instance, 1 to 1.4 as measured before radial or star polymer
formation or on uncoupled units. In one embodiment the overall
polymer composition, which includes the polymer with radial or star
architecture, has polydispersity with a bimodal or higher modal
distribution. The bimodal or higher distribution in the overall
composition is believed to be partially due to the presence of
varying amounts of uncoupled polymer chains and/or uncoupled radial
or star-polymers or star-to-star coupling formed as the polymer is
prepared.
[0069] The overall composition containing polymers with the radial
or star architecture may thus also have uncoupled polymeric arms
present (also referred to as a polymer chain or linear polymer).
The percentage conversion of a polymer chain to radial or star
polymer may be at least 10%, or at least 20%, or at least 40%, or
at least 55%, for instance at least 70%, at least 75% or at least
80%. In one embodiment the conversion of polymer chain to radial or
star polymer may be 90%, 95% or 100%. In one embodiment a portion
of the polymer chains does not form a star polymer and remains as a
linear polymer. In one embodiment the polymer is a mixture of (i) a
polymer with radial or star architecture, and (ii) linear polymer
chains (also referred to as uncoupled polymeric arms). In different
embodiments the amount of radial or star architecture within the
polymer composition may be 10 wt % to 85 wt %, or 25 wt % to 70 wt
% of the amount of polymer. In different embodiments the linear
polymer chains may be present at 15 wt % to 90 wt %, or 30 wt % to
75 wt % of the amount of polymer.
[0070] The 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 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.
[0071] The 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 polymer may also be obtained/obtainable from anionic
polymerisation processes. In one embodiment the polymer may be
obtained/obtainable from RAFT, ATRP or anionic polymerisation
processes. In one embodiment the polymer may be obtained/obtainable
from RAFT or ATRP polymerisation processes. In one embodiment the
polymer may be obtained/obtainable from a RAFT polymerisation
process.
[0072] Methods of preparing polymers using ATRP, RAFT or
nitroxide-mediated techniques are disclosed in the example section
of U.S. patent application Ser. No. 05/038,146, examples 1 to
47.
[0073] More detailed descriptions of polymerisation mechanisms and
related chemistry is discussed for nilroxide-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
Malyjaszewski and Thomas P. Davis, 2002, published by John Wiley
and Sons Inc (hereinafter referred to as "Malyjaszewski et
al.").
[0074] The discussion of the 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 Malyjaszewski et al.
[0075] 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 U.S. patent application Ser. No.
05/038,146.
[0076] Examples of a halogen-containing compound that may be used
in ATRP polymerisation include benzyl halides such as
p-chloromethylstyrene, .alpha.-dichloroxylene,
.alpha.,.alpha.-dichloroxylene, .alpha.,.alpha.-dibromoxylene,
hexakis(.alpha.-bromomethyl)benzene, benzyl chloride, benzyl
bromide, 1-bromo-1-phenylethane and 1-chloro-1-phenylelhane;
carboxylic acid derivatives which are halogenated at the
.alpha.-position, such as propyl 2-bromopropionate, methyl
2-chloropropionate, ethyl 2-chloropropionate, methyl
2-bromopropionate, and ethyl 2-bromoisobulyrate; tosyl halides such
as p-toluenesulfonyl chloride; alkyl halides such as
tetrachloromethane, tribromomethane, 1-vinylethyl chloride, and
1-vinylethyl bromide; and halogen derivatives of phosphoric acid
esters, such as dimethylphosphoric acid.
[0077] In one embodiment when the halogen compound is employed, a
transition metal such as copper is also present. The transition
metal may be in the form of a salt. The transition metal is capable
of forming a metal-to-ligand bond and the ratio of ligand to metal
depends on the dentate number of the ligand and the co-ordination
number of the metal. The ligand may be a nitrogen or
phosphorus-containing ligand.
[0078] Examples of a suitable ligand include triphenylphosphine,
2,2-bipyridine, alkyl-2,2-bipyridine, such as
4,4-di-(5-heptyl)-2,2-bipyridine, tris(2-aminoethyl)amine (TREN),
N,N,N',N',N''-pentamelhyldiethylenetriamine,
4,4-di-(5-nonyl)-2,2-bipyridine, 1,1,4,7,10,10-hexamethyl tri ethyl
enetetramine and/or tetramethylethylenediamine. Further suitable
ligands are described in, for example, International Patent
application WO 97/47661. The ligands may be used individually or as
a mixture. In one embodiment the nitrogen containing ligand is
employed in the presence of copper. In one embodiment the ligand is
phosphorus-containing with triphenyl phosphine (PPh.sub.3) a common
ligand. A suitable transition metal for a triphenyl phosphine
ligand includes Rh, Ru, Fe, Re, Ni or Pd.
[0079] In RAFT polymerisation, chain transfer agents are important.
A more detailed review of suitable chain transfer agents is found
in paragraphs 66 to 71of U.S. patent application Ser. No.
05/038,146. Examples of a suitable RAFT chain transfer agent
include benzyl 1-(2-pyrrolidinonc)carbodithioate, benzyl
(1,2-benzenedicarboximido) carbodithioate, 2-cyanoprop-2-yl
1-pyrrolecarbodithioate, 2-cyanobut-2-yl 1-pyrrolecarbodithioate,
benzyl 1-imidazolecarbodithioate,
N,N-dimethyl-S-(2-cyanoprop-2-yl)dithiocarbamate,
N,N-diethyl-5-benzyl dithiocarbamate, cyanomethyl 1-(2-pyrrolidone)
carbodithoate, cumyl dithiobenzoate,
2-dodecylsulphanylthiocarbonylsulphanyl-2-methyl-propionic acid
butyl ester, O-phenyl-5-benzyl xanthate, N,N-diethyl
S-(2-ethoxy-carbonylprop-2-yl)dithiocarbamate, dithiobenzoic acid,
4-chlorodithiobenzoic acid, O-ethyl-S-(1-phenylethyl)xanthtate,
O-ethyl-S-(2-(ethoxycarbonyl)prop-2-yl)xanthate,
O-ethyl-S-(2-cyanoprop-2-yl)xanthate,
O-ethyl-S-(2-cyanoprop-2-yl)xanthate, O-ethyl-5-cyanomethyl
xanthate, O-pentafluorophenyl-5-benzyl xanthate,
3-benzylthio-5,5-dimethylcyclohex-2-ene-1-thione or benzyl
3,3-di(benzylthio)prop-2-enedithioate,
S,S'-bis-(.alpha.,.alpha.'disubstituted-.alpha.''-acetic
acid)-trithiocarbonate,
S,S'-bis-(.alpha.,.alpha.'-disubstituted-.alpha.''-acetic
acid)-trithiocarbonate or
S-alkyl-S'-(.alpha.,.alpha.'-disubstituted-.alpha.''-acetic
acid)-trithiocarbonates, benzyl dithiobenzoate, 1-phenylethyl
dithiobenzoate, 2-phenylprop-2-yl dithiobenzoate, 1-acetoxyethyl
dithiobenzoate, hexakis(thiobenzoylthiomethyl)benzene,
1,4-bis(thiobenzoylthiomethyl)benzene,
1,2,4,5-tetrakis(thiobenzoylthiomethyl)benzene,
1,4-bis-(2-(thiobenzoylthio)-prop-2-yl)benzene,
1-(4-methoxyphenyl)ethyl dithiobenzoate, benzyl dithioacetate,
ethoxycarbonylmethyl dithioacetate, 2-(ethoxycarbonyl)prop-2-yl
dithiobenzoate, 2,4,4-trimethylpent-2-yl dithiobenzoate,
2-(4-chlorophenyl)prop-2-yl dithiobenzoate, 3-vinylbenzyl
dithiobenzoate, 4-vinylbenzyl dithiobenzoate, S-benzyl
diethoxyphosphinyldithioformate, tert-butyl trithioperbenzoate,
2-phenylprop-2-yl 4-chlorodithiobenzoate, 2-phenylprop-2-yl
1-dithionaphthalate, 4-cyanopentanoic acid dithiobenzoate, di
benzyl tetrathioterephthalate, dibenzyl irithiocarbonate,
carboxymethyl dithiobenzoate or poly(ethylene oxide) with
dithiobenzoate end group or mixtures thereof.
[0080] In one embodiment a suitable RAFT chain transfer agent
includes 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl-propionic
acid butyl ester, cumyl dithiobenzoate or mixtures thereof.
[0081] A discussion of the polymer mechanism of RAFT polymerisation
is shown on page 664 to 665 in section 12.4.4 of Matyjaszewski et
al.
[0082] When the polymer is prepared from anionic polymerisation
techniques, initiators include, for example, hydrocarbyllithium
initiators such as alkyllithium compounds (e.g., methyl lithium,
n-butyl lithium, sec-butyl lithium), cycloalkyllithium 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-tetraphenyl butane,
diphenylmethyl potassium or diphenylmethyl sodium.
[0083] The polymerisation process may also be carried out in the
absence of moisture and oxygen and in the presence of at least one
inert solvent. In one embodiment anionic polymerisation is
conducted in the absence of any impurity which is detrimental to an
anionic catalyst system. The inert solvent includes a hydrocarbon,
an aromatic solvent or ether. Suitable solvents include isobutane,
pentane, cyclohexane, benzene, toluene, xylene, tetrahydrofuran,
diglyme, tetraglyme, orthoterphenyl, biphenyl, decalin or
tetralin.
[0084] The anionic polymerisation process may be carried out at a
temperature of 0.degree. C. to -78.degree. C.
[0085] A more detailed description of process to prepare the
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 Polymer Science,
edited by Fred W. Billmeyer Jr., Third Edition, 1984, Chapter 4,
pages 88-90.
[0086] The polymer may comprise at least one of (a) a 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
polymer with pendant groups comprises a polymethacrylate or
mixtures thereof.
[0087] When the polymer is a polymethacrylate, the polymer may be
derived from a monomer composition comprising:
[0088] (a) 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;
[0089] (b) 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
[0090] (c) 0 wt % to 10 wt % (or 0 wt % to 5 wt %) of a
nitrogen-containing monomer.
[0091] As used herein the term (meth)acrylate means acrylate or
methacrylate units. The alkyl(meth)acrylate includes for example
compounds derived from saturated alcohols, such as methyl
methacrylate, butyl methacrylate, 2-methylpentyl, 2-propylheptyl,
2-butyloctyl, 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)-acrylale,
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, 5-isopropylheptadecyl(meth)acrylate,
4-tert-butyloctadecyl(meth)acrylate,
5-ethyloctadecyl(meth)acrylate,
3-isopropyloctadecyl-(meth)acrylate, octadecyl(meth)acrylate,
nonadecyl (meth)acrylate, eicosyl(meth)acrylate,
cetyleicosyl(meth)acrylate, stearyleicosyl(meth)acrylate,
docosyl(meth)acrylale 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.
[0092] The alkyl(meth)acrylates with long-chain alcohol-derived
groups may be obtained, for example, by reaction of a (meth)acrylic
acid (by direct estcrification) or methyl methacrylate (by
transesterification) with long-chain fatty alcohols, in which
reaction a mixture of esters such as (meth)acrylate with alcohol
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 TCT;
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.
[0093] In one embodiment the star polymer is further functionalised
in the core or the polymeric arms with a nitrogen-containing
monomer. The nitrogen-containing monomer may include a
vinyl-substituted nitrogen heterocyclic monomer, a
dialkylaminoalkyl(meth)acrylate monomer, a dialkylaminoalkyl
methacrylamide monomer, a tertiary-methacrylamide, a
dialkylaminoalkyl acrylamide monomer, a tertiary-acrylamide monomer
or mixtures thereof.
[0094] In one embodiment the core or polymeric arms further
comprise a (meth)acrylamide or a nitrogen containing (meth)acrylate
monomer that may be represented by the formula:
##STR00003##
wherein [0095] Q is hydrogen or methyl and, in one embodiment, Q is
methyl; [0096] Z is an N--H group or O (oxygen); [0097] each
R.sup.ii is independently hydrogen or a hydrocarbyl group
containing 1 to 8, or 1 to 4 carbon atoms; [0098] each R.sup.i is
independently hydrogen or a hydrocarbyl group containing 1 to 2
carbon atoms and, in one embodiment, each R.sup.i is hydrogen; and
[0099] g is an integer from 1 to 6 and, in one embodiment, g is 1
to 3.
[0100] Examples of a suitable nitrogen-containing monomer include
N,N-dimethylacrylamide, N-vinyl carbonamides such as
N-vinyl-formamide, vinyl pyridine, N-vinylacetamide,
N-vinyl-n-propionamides, N-vinyl hydroxyacetamide, N-vinyl
imidazole, N-vinyl pyrrolidinone, N-vinyl caprolactam,
dimethylaminoethyl acrylate (DMAEA), dimethylaminoethylmethacrylate
(DMAEMA), dimethylaminobutylacrylamide, dimethyl
amine-propylmethacrylate (DMAPMA), dimethylamine-propyl-acryl
amide, dimethylaminopropylmethaerylamide,
dimethylaminoethyl-acrylamide or mixtures thereof.
[0101] The polymer may be present at 0.01 to 12 wt %, or 0.05 wt %
to 10 wt %, or 0.075 to 8 wt % of the lubricating composition.
Dispersant
[0102] The lubricating composition comprises a dispersant. The
dispersant may be a succinimide dispersant (for example
N-substituted long chain alkenyl succinimides), a Mannich
dispersant, an ester-containing dispersant, a condensation product
of a long chain hydrocarbyl (such as a fatty hydrocarbyl or
polyisobutylene) monocarboxylic acylating agent with an amine or
ammonia, an alkyl amino phenol dispersant, a hydrocarbyl-amine
dispersant, a polyether dispersant, or a polyetheramine
dispersant.
[0103] In different embodiments the dispersant may be a
succinimide, succinic acid ester, or Mannich dispersant.
[0104] In several embodiments the N-substituted long chain alkenyl
succinimides contain an average of at least 8, or 30, or 35 up to
350, or to 200, or to 100 carbon atoms. In one embodiment, the long
chain alkenyl group is derived from a polyalkene characterised by
an M.sub.n (number average molecular weight) of at least 500.
Generally, the polyalkene is characterised by an M.sub.n of 500, or
700, or 800, or even 900 up to 5000, or to 2500, or to 2000, or
even to 1500 or 1200. In one embodiment the long chain alkenyl
group is derived form polyolefins. The polyolefins may be derived
from monomers including monoolefins having 2 to 10 carbon atoms
such as ethylene, propylene, 1-butene, isobutylene, and 1-decene.
An especially useful monoolefin source is a C.sub.4 refinery stream
having a 35 to 75 weight percent butene content and a 30 to 60
weight percent isobutene content. Useful polyolefins include
polyisobutylenes having a number average molecular weight of 140 to
5000, in another instance of 400 to 2500, and in a further instance
of 140 or 500 to 1500. The polyisobutylenc may have a vinylidene
double bond content of 5 to 69%, in a second instance of 50 to 69%,
and in a third instance of 50 to 95%.
[0105] In one embodiment the succinimide dispersant comprises a
polyisobutylene succinimide, wherein the polyisobutylene has a
number average molecular weight of 140 to 5000, or 300 to 5000, or
500 to 3000.
[0106] Succinimide dispersants and their methods of preparation are
more fully described in U.S. Pat. Nos. 4,234,435 and 3,172,892.
[0107] Suitable ester-containing dispersants are typically high
molecular weight esters. These materials are described in more
detail in U.S. Pat. No. 3,381,022.
[0108] Mannich dispersants are the reaction product of a
hydrocarbyl-substituted phenol, an aldehyde, and an amine or
ammonia. The hydrocarbyl substituent of the hydrocarbyl-substituted
phenol may have 10 to 400 carbon atoms, in another instance 30 to
180 carbon atoms, and in a further instance 10or 40 to 110 carbon
atoms. This hydrocarbyl substituent may be derived from an olefin
or a polyolefin. Useful olefins include alpha-olefins, such as
1-decene, which are commercially available.
[0109] Hydrocarbyl-amine dispersants are hydrocarbyl-substituted
amines. The hydrocarbyl-substituted amine may be formed by heating
a mixture of a chlorinated olefin or polyolefin such as a
chlorinated polyisobutylene with an amine such as ethylenediamine
in the presence of a base such as sodium carbonate as described in
U.S. Pat. No. 5,407,453.
[0110] Polyether dispersants include polyetheramines, polyether
amides, polyether carbamates, and polyether alcohols.
Polyetheramines and their methods of preparation are described in
greater detail in U.S. Pat. No. 6,458,172, columns 4 and 5.
[0111] In one embodiment the invention further comprises at least
one dispersant derived from polyisobutylene succinic anhydride, an
amine and zinc oxide to form a polyisobutylene succinimide complex
with zinc. The polyisobutylene succinimide complex with zinc may be
used alone or in combination.
[0112] The dispersants may also be post-treated by conventional
methods by a reaction with any of a variety of agents. Among these
are boron, urea, thiourea, dimercaptothiadiazoles, carbon
disulphide, aldehydes, ketones, carboxylic acids,
hydrocarbon-substituted succinic anhydrides, maleic anhydride,
nitriles, epoxides, phosphorus compounds and/or metal compounds. In
one embodiment the dispersant is a borated dispersant. Typically
the borated dispersant comprises the succinimide dispersant
comprises a polyisobutylene succinimide, wherein the
polyisobutylene has a number average molecular weight of 140 to
5000, or 300 to 5000, or 500 to 3000.
[0113] In one embodiment the dispersant may be prepared by heating
(i) a dispersant material described above (for example
N-substituted long chain alkenyl succinimides), (ii)
2,5-dimercapto-1,3,4-thiadiazole or a hydrocarbyl-substituted
2,5-dimercapto-1,3,4-thiadiazole, or oligomers thereof, (iii) a
borating agent, and (iv) optionally a dicarboxylic acid of an
aromatic compound selected from the group consisting of 1,3 diacids
and 1,4 diacids; or (v) optionally a phosphorus acid compound, said
heating being sufficient to provide a product of (i), (ii), (iii)
and optionally (iv) or (v), which is soluble in an oil of
lubricating viscosity. The dispersant prepared by heating is
described in more detail in U.S. patent application Ser. Nos.
04/027,094 and 60/654,164.
[0114] The dispersant may be present at 0.1 wt % to 20 wt %, or
0.25 wt % to 15 wt %, or 0.5 wt % to 10 wt %, or 1 wt % to 6 wt %,
or 7 wt % to 12 wt % of the lubricating composition.
Oils of Lubricating Viscosity
[0115] 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 and re-refined oils and mixtures thereof.
[0116] Unrefined oils are those obtained directly from a natural or
synthetic source generally without (or with little) further
purification treatment.
[0117] Refined oils are similar to the unrefined oils except they
have been further treated in one or more purification steps to
improve one or more properties. Purification techniques are known
in the art and include solvent extraction, secondary distillation,
acid or base extraction, filtration, percolation and the like.
[0118] Re-refined oils are also known as reclaimed or reprocessed
oils, and are obtained by processes similar to those used to obtain
refined oils and often are additionally processed by techniques
directed to removal of spent additives and oil breakdown
products.
[0119] Natural oils useful in making the inventive lubricants
include animal oils, vegetable oils (e.g., castor oil, lard oil),
mineral lubricating oils such as liquid petroleum oils and
solvent-treated or acid-treated mineral lubricating oils of the
paraffinic, naphthenic or mixed paraffinic-naphthenic types and
oils derived from coal or shale or mixtures thereof.
[0120] Synthetic lubricating oils are useful and include
hydrocarbon oils such as polymerised and interpolymerised olefins
(e.g., poiybutylenes, polypropylenes, propyleneisobutylene
copolymers); poly(1-hexenes), poly(1-octenes), poly(1-decenes), and
mixtures thereof; alkyl-benzenes (e.g. dodecylbenzenes,
tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes);
polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls);
alkylated diphenyl ethers and alkylated diphenyl sulphides and the
derivatives, analogs and homologs thereof or mixtures thereof.
[0121] Other synthetic lubricating oils include polyol esters (such
as Prolube.RTM.3970), diesters, liquid esters of
phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl
phosphate, and the diethyl ester of decane phosphonic acid), or
polymeric tetrahydrofurans. Synthetic oils may be produced by
Fischer-Tropsch reactions and typically may be hydroisomerised
Fischer-Tropsch hydrocarbons or waxes. Tn one embodiment oils may
be prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure
as well as other gas-to-liquid oils.
[0122] Oils of lubricating viscosity may also be defined as
specified in the American Petroleum Institute (API) Base Oil
Interchangeability Guidelines. The five base oil groups are as
follows: Group I (sulphur content >0.03 wt %, and/or <90 wt %
saturates, viscosity index 80-120); Group II (sulphur content
.ltoreq.0.03 wt %, and .gtoreq.90 wt % saturates, viscosity index
80-120); Group III (sulphur content .ltoreq.0.03 wt %, and
.gtoreq.90 wt % saturates, viscosity index .gtoreq.120); Group IV
(all polyalphaolefins (PAOs)); and Group V (all others not included
in Groups I, II, III, or IV). The oil of lubricating viscosity
comprises an API Group I, Group II, Group III, Group IV, Group V
oil or mixtures thereof. Often the oil of lubricating viscosity is
an API Group I, Group II, Group III, Group IV oil or mixtures
thereof. Alternatively the oil of lubricating viscosity is often an
API Group II, Group III or Group IV oil or mixtures thereof. In one
embodiment the oil of lubricating viscosity is a API Group III
oil.
[0123] 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 polymer, the overbased detergent, the
dispersant and other performance additives.
[0124] The lubricating composition may be in the form of a
concentrate and/or a fully formulated lubricant. If the polymer,
the overbased detergent, the dispersant are 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
components (a), (b) and (c) (i.e. the polymer, the overbased
detergent, the dispersant 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
[0125] The composition optionally comprises other performance
additives. The other performance additives comprise at least one of
metal deactivators, viscosity modifiers, friction modifiers,
antiwear agents, corrosion inhibitors, dispersant viscosity
modifiers, extreme pressure 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.
Antioxidants
[0126] Antioxidant compounds are known and include for example,
sulphurised olefins, alkylated diphenylamines (typically di-nonyl
diphenylamine, octyl diphenylamine, di-octyl diphenylamine),
hindered phenols, molybdenum compounds (such as molybdenum
dithiocarbamates), or mixtures thereof. Antioxidant compounds may
be used alone or in combination. The antioxidant may be present in
ranges 0 wt % to 20 wt %, or 0.1 wt % to 10 wt %, or 1 wt % to 5 wt
%, of the lubricating composition.
[0127] In one embodiment the antioxidant is a molybdenum compound.
Typically the molybdenum compound provides 10 to 2000, or 20 to
1000, or 50 to 500 parts per million by weight molybdenum to the
lubricating composition.
[0128] 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-cli-tert-butylphenol, or
4-dodecyl-2,6-di-tert-butylphenol. In one embodiment the hindered
phenol antioxidant is an ester and may include, e.g., Irganox.TM.
L-135 from Ciba, or a condensation product derived from
2,6-di-tert-butylphenol and an alkyl acrylate, wherein the alkyl
group may contain 1 to 18, or 2 to 12, or 2 to 8, or 2 to 6, or 4
carbon atoms. A more detailed description of suitable
ester-containing hindered phenol antioxidant chemistry is found in
U.S. Pat. No. 6,559,105.
[0129] Suitable examples of molybdenum dithiocarbamates which may
be used as an antioxidant include commercial materials sold under
the trade names such as Molyvan 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.
Antiwear Agents
[0130] The lubricant composition optionally further comprises at
least one other antiwear agent. The antiwear agent may be present
in ranges including 0 wt % to 15 wt %, or 0.1 wt % to 10 wt % or 1
wt % to 8 wt % of the lubricating composition. Examples of suitable
antiwear agents include phosphate esters, sulphurised olefins,
sulphur-containing ashless anti-wear additives are metal
dihydrocarbyldithiophosphates (such as zinc dialkyldithiophosphates
or molybdenum dialkyldithiophosphates), thiocarbamate-containing
compounds, such as thiocarbamate esters, thiocarbamate amides,
thiocarbamic ethers, alkylene-coupled thiocarbamales, and
bis(S-alkyldithiocarbamyl) disulphides.
[0131] 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 of 25.degree. C. to 125.degree. C. U.S. Pat. Nos.
4,758,362 and 4,997,969 describe dithiocarbamate compounds and
methods of making them.
[0132] 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, penladecene, 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.
[0133] 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 such as alpha-olefins e.g., 1-hexadecene.
[0134] In an alternative embodiment, the ashless antiwear agent
(which may also be described as a friction modifier) 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
ashless antiwear agent mixture include 5 to 95, or in other
embodiments 10 to 90, or 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 14 to 20 carbon atoms. Examples of
carboxylic acids include dodecanoic acid, stearic acid, 1 auric
acid, behenic acid, and oleic acid.
[0135] 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
pentaerythritols, including di- and tripentaerythritol. Often the
polyol is diethyl-ene glycol, triethylene glycol, glycerol,
sorbitol, pentaerythritol or dipentaerythritol.
[0136] 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.
Viscosity Modifiers
[0137] Viscosity modifiers other than the polymer (a) of the
invention, including hydrogenated copolymers of styrene-butadiene,
ethylene-propylene copolymers, polyisobutenes, hydrogenated
styrene-isoprene polymers, hydrogenated isoprene polymers,
polymethacrylates, polyacrylates, polyalkyl styrenes, alkenyl aryl
conjugated diene copolymers, polyolefins, esters of maleic
anhydride-styrene copolymers. Conventional poly(meth)acrylate
polymers may be derived from monomers substantially the same as
those defined for the polymeric arms. However, the conventional
poly(meth)acrylate is generally free of a functional group selected
from a halogen, an --O--N.dbd. group and an --S--C(.dbd.S)-- group.
In one embodiment the polymer of the invention is mixed with a
conventional viscosity modifier.
[0138] The viscosity modifier other than polymer (a) of the
invention may be present at 0 wt % to 15 wt %, or 0.01 to 12 wt %,
or 0.05 to 10 wt %, or 0.075 to 8 wt % of the lubricating
composition.
Extreme Pressure Agents
[0139] 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; 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, clistearyl phosphite and
polypropylene substituted phenol phosphite; metal thiocarbamates
such as zinc dioctyldithiocarbamate and barium heptylphenol diacid;
amine salts of alkyl and dialkylphosphoric acids, including, for
example, the amine salt of the reaction product of a
dialkyldithiophosphoric acid with propylene oxide; and mixtures
thereof.
Other Additives
[0140] Other performance additives such as corrosion inhibitors
include those described in paragraphs 5 to 8 of U.S. application
Ser. No. 05/038319 (filed on Oct. 25, 2004 McAtee and Boyer as
named inventors), octylamine octanoate, condensation products of
dodecenyl succinic acid or anhydride and a fatty acid such as oleic
acid with a polyamine. In one embodiment the corrosion inhibitors
include the Synalox.RTM. corrosion inhibitor. The Synalox.RTM.
corrosion inhibitor is typically a homopolymer or copolymer of
propylene oxide. The Synalox.RTM. corrosion inhibitor is described
in more detail in a product brochure with Form No. 118-01453-0702
AMS, published by The Dow Chemical Company. The product brochure is
entitled "SYNALOX Lubricants, High-Performance Polyglycols for
Demanding Applications."
[0141] Metal deactivators including derivatives of benzotriazoles
(typically tolyltriazole), dimercaptothiadiazole 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 trialkyl phosphates, 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.
[0142] Friction modifiers including fatty acid derivatives such as
amines, esters, epoxides, fatty imidazolines, condensation products
of carboxylic acids and polyalkylene-polyamines and amine salts of
alkylphosphoric acids, fatty alkyl tartrates (typically fatty di
alkyl tartrates), fatty alkyl tartrimides, fatty alkyl lartramides
(typically fatty di alkyl tartramides) may also be used in the
lubricant composition. Friction modifiers may also encompass
materials such as sulphurised fatty compounds and olefins,
molybdenum dialkyldithiophosphates, molybdenum dithiocarbamates,
sunflower oil or monoester of a polyol and an aliphatic carboxylic
acid (several of these friction modifiers have been described above
as antioxidants or as antiwear agents). Friction modifiers may be
present in ranges including 0 wt % to 10 wt % or 0.1 wt % to 8 wt %
or 1 wt % to 5 wt % of the lubricating composition.
INDUSTRIAL APPLICATION
[0143] The method of the invention is useful for lubricating a
variety of mechanical devices. The mechanical device comprises at
least one of an internal combustion engine (for crankcase
lubrication), a hydraulic system, a turbine system, a circulating
oil system, an industrial oil system, a gear, a gearbox, an
automatic transmission or a manual transmission.
[0144] In different embodiments the mechanical device comprises an
internal combustion engine. The internal combustion engine may be a
2-stroke or a 4-stroke internal combustion engine and may or may
not be sump-lubricated.
[0145] In one embodiment the internal combustion engine may be a
diesel fuelled engine, a gasoline fuelled engine, a natural gas
fuelled engine or a mixed gasoline/alcohol fuelled engine. In one
embodiment the internal combustion engine is a diesel fuelled
engine and in another embodiment a gasoline fuelled engine.
Suitable internal combustion engines include marine diesel engines,
aviation piston engines, low-load diesel engines, and automobile
and truck engines.
[0146] In one embodiment the internal combustion engine 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.
[0147] 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).
[0148] 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.
[0149] In one embodiment the internal combustion engine is a
4-stroke engine. In one embodiment the internal combustion engine
is also referred to genetically as a small engine.
[0150] 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 or
chainsaws.
[0151] 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.
[0152] 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.
[0153] In one embodiment the internal combustion engine is suitable
for motorcycles for example motorcycles with a 4-stroke internal
combustion engine.
[0154] In different embodiments the lubricating composition
comprises a lubricant for an internal combustion engine with a SAE
viscosity grade from XW-Y, wherein X is an integer from 0 to 20 and
Y is an integer from 20 to 50.
[0155] In several embodiments X is an integer chosen from 0, 5, 10,
15 or 20; and Y is an integer chosen from 20, 25, 30, 35, 40, 45 or
50.
[0156] The lubricant composition for an internal combustion engine
may be suitable for any engine lubricant irrespective of the
sulphur, phosphorus or sulphated ash (ASTM D-874) content. The
sulphur content of the engine oil lubricant may be 1 wt % or less,
or 0.8 wt % or less, or 0.5 wt % or less, or 0.3 wt % or less. In
one embodiment the sulphur content may be 0.1 wt % to 0.5 wt %. The
phosphorus content may be 0.2 wt % or less, or 0.1 wt % or less, or
0.085 wt % or less, or even 0.06 wt % or less, 0.055 wt % or less,
or 0.05 wt % or less. In different embodiments the phosphorus
content may be 0.01 wt % 0.075 wt %, or 0.01 wt % 0.06 wt %. The
total sulphated ash content may be 2 wt % or less, or 1.5 wt % or
less, or 1.1 wt % or less, or 1 wt % or less, or 0.8 wt % or less,
or 0.5 wt % or less. In one embodiment the sulphated ash content
may be 0.1 wt % to 0.5 wt %.
[0157] In one embodiment the lubricating composition comprises an
engine oil, wherein the lubricating composition has a (i) a sulphur
content of 0.5 wt % or less, (ii) a phosphorus content of 0.1 wt %
or less, and (iii) a sulphated ash content of 1.5 wt % or less.
[0158] In one embodiment the lubricating composition is suitable
for a 2-stroke or a 4-stroke marine diesel internal combustion
engine. In one embodiment the marine diesel combustion engine is a
2-stroke engine. The polymer of the invention may be added to a
marine diesel lubricating composition at 0.01 to 15 wt %, or 0.05
to 10 wt %, or 0.1 to 5 wt %.
[0159] The following examples provide illustrations of the
invention. These examples are non exhaustive and are not intended
to limit the scope of the invention.
EXAMPLES
[0160] For each chemical component used in the following examples,
the amount presented exclusive of any solvent or diluent oil, which
may be customarily present in the commercial material (i.e. each
chemical component is presented on an actives basis).
Preparative Example 1 (Prep 1)
[0161] A vessel equipped with a nitrogen inlet flowing at 28.3
L/hr, medium speed mechanical stirrer, a thermocouple and a
water-cooled condenser is charged with 80 g of C.sub.12-15 alkyl
methacrylate, 20 g of methyl methacrylate, 0.55 g of
Trigonox.TM.-21 (initiator), 4.07 g of
2-dodecylsulphanylthiocarbonylsLilphanyl-2-melhyl-propionic acid
dodecyl ester (chain transfer agent) and 48.2 g of oil. The
contents of the vessel are stirred under a nitrogen blanket for 20
minutes to ensure sufficient mixing. The nitrogen flow is reduced
to 14.2 L/hr and the mixture is set to be heated to 90.degree. C.
for 3 hours. 6.05 g of ethylene glycol dimethacrylate is added to
the vessel and the mixture is stirred at 90.degree. C. for an
additional 3 hours. The resultant product is a mixture of polymers
and is then cooled to ambient temperature. The major product
fraction is characterised as having a weight average molecular
weight of 283,300 g/mol and having a number average molecular
weight of 215,900 g/mol. The polymer is believed to have at least 9
polymeric arms (containing 80 wt % of C.sub.12-15
alkylmethacrylate, 20 wt % of methyl methacrylate) and the
conversion to a star polymer is 72%, with 28% uncoupled linear
polymer chains.
Preparative Example 2 (Prep 2)
[0162] The process to prepare Prep 2 is similar to Prep 1 above,
except the amounts of reactants are as follows: 0.63 g of chain
transfer agent, 0.11 g of initiator, 68.8 g of C12-15 alkyl
methacrylate, 11.2 g of methyl methacrylate, 1.58 g of ethylene
glycol dimethacrylate. The resultant polymer has a weight average
molecular weight of 407,600, and a number average molecular weight
of 289,900. The star polymer is believed to have at least 5 arms,
and the conversion to star polymer is 70%, with 30% uncoupled
linear polymer chains.
Preparative Example 3 (Prep 3)
[0163] The process to prepare Prep 3 is similar to Prep 1 above,
except the amounts of reactants are as follows: 0.71 g of chain
transfer agent, 0.14 g of initiator, 80 g of C12-15 alkyl
methacrylate, 20 g of methyl methacrylate, 1.59 g of ethylene
glycol dimethacrylate. The resultant polymer has a weight average
molecular weight of 696,100, and a number average molecular weight
of 814,600. The star polymer is believed to have at least 6 arms,
and the conversion to star polymer is 40%, with 60% uncoupled
linear polymer chains.
[0164] Lubricating composition 1 (LC1) contains 6 wt % of the
polymer from Prep 1, 1.4 wt % of dispersant, 0.6 wt % of 300 TBN
sulphonate detergent, 1 wt % of 255 TBN phenate, 0.2 wt % of
polyacrylate pour point depressant, 2 wt % of other additives
(including antiwear agents and antifoam agents) and the balance to
100 wt % being base oil. LC1 has a viscosity grade of 10 W-40.
[0165] Comparative lubricating composition 1 (CLC1) is
substantially the same as LC1, except the polymer from Prep1 is
replaced with 12 wt % of a commercially available linear
polymethacrylate. The amount of base oil is modified accordingly in
view of the increased amounts of polymer. CLC1 has a viscosity
grade of 10 W-40.
[0166] The lubricating compositions LC1 and CLC1 are evaluated by
determining the kinematic viscosity at 100.degree. C. (using ASTM
method D445) before and after subjecting the lubricating
compositions to KRL tapered bearing shear test at 80.degree. C. for
4 hours. The lubricating compositions are also evaluated for cold
crank properties at -25.degree. C. (using ASTM D5293) and high
temperature high shear (HTHS) properties (using CEC-L-36-A-90). The
results obtained as follows:
TABLE-US-00001 Test LC1 CLC1 Kinematic Viscosity at 100.degree. C.
12.17 12.44 (before shear test) Kinematic Viscosity at 100.degree.
C. 11.02 11.49 (after shear test) Viscosity loss during test
(mm.sup.2/s) 1.15 0.95 Viscosity loss (%) 9.45 7.64 Cold crank
properties at -25.degree. C. 6320 4410 HTHS 3.51 4.1
[0167] Lubricating composition 2 (LC2) contains 2.9 wt % of the
polymer from Prep1, 0.9 wt % of 300 TBN overbased detergents, 3 wt
% of succinimide dispersants, 0.2 wt % of a polyacrylate pour point
depressant, and 1.8 wt % of other additives (including antiwear
agents and antioxidants). LC2 has a viscosity grade of 0 W-20. LC2
has kinematic viscosity at 100.degree. C. of 8.13 mm.sup.2/s, cold
crank properties at -35.degree. C. (using ASTM D5293) of 6180, and
high temperature high shear (HTHS) properties (using CEC-L-36-A-90)
of 2.60.
[0168] Lubricating composition 3 (LC3) contains 2.9 wt % of the
polymer from Prep2, 2.6 wt % dispersants, 0.9 wt % overbased
detergents 0.3 wt % of polyacrylate pour point depressant, 2.5 wt %
of other additives and balance is base oil. LC3 is then evaluated
in a number of tests. The tests include high temperature high shear
properties using ASTM method D4683 (result obtained: 3.19); and for
cold crank properties using ASTM method D5293 at -30.degree. C.
(result obtained: 6059 mm.sup.2/s). LC3 is also evaluated using
Orbahn shear test (ASTM D6278). The results obtained include a
final test viscosity is 10.09 mm.sup.2/s, a viscosity loss (%) of
8.69, and a shear stability of 16.0.
[0169] Lubricating composition 4 (LC4) is substantially the same as
LC3, except the polymer used is from Prep3 at 2.3 wt %, and the
amount of base oil is modified accordingly. LC4 is then evaluated
in a number of tests. The tests include high temperature high shear
properties using ASTM method D4683 (result obtained: 3.16); and for
cold crank properties using ASTM method D5293 at -25.degree. C.
(result obtained: 2751 min.sup.2/s). LC4 is also evaluated using
Orbahn shear test (ASTM D6278). The results obtained include a
final test viscosity is 9.13 mm.sup.2/s, a viscosity loss (%) of
12.21, and a shear stability of 23.7.
[0170] 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:
[0171] (i) hydrocarbon substituents, that is, aliphatic (e.g.,
alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl)
substituents, and aromatic-, aliphatic-, and alicyclic-substituted
aromatic substituents, as well as cyclic substituents wherein the
ring is completed through another portion of the molecule (e.g.,
two substituents together form a ring);
[0172] (ii) 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 (e.g., halo (especially
chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto,
nitro, nitroso, and sulphoxy);
[0173] (iii) hetero substituents, that is, substituents which,
while having a predominantly hydrocarbon character, in the context
of this invention, contain other than carbon in a ring or chain
otherwise composed of carbon atoms. Heleroatoms include sulphur,
oxygen, nitrogen, and encompass substituents as pyridyl, furyl,
thienyl and imidazolyl. In general, no more than two, preferably 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.
[0174] 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.
[0175] 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.
[0176] While the invention has been explained in relation to its
various 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.
* * * * *