U.S. patent application number 14/772417 was filed with the patent office on 2016-01-14 for lubricating composition.
The applicant listed for this patent is SHELL OIL COMPANY. Invention is credited to Sarah Jane MATTHEWS, Mark Clift SOUTHBY, Zhou XU.
Application Number | 20160010023 14/772417 |
Document ID | / |
Family ID | 50277199 |
Filed Date | 2016-01-14 |
United States Patent
Application |
20160010023 |
Kind Code |
A1 |
MATTHEWS; Sarah Jane ; et
al. |
January 14, 2016 |
LUBRICATING COMPOSITION
Abstract
Use of a comb polymer for reducing the loss in viscosity of a
lubricating composition for the crankcase of an internal combustion
engine, wherein the internal combustion engine is fuelled by a fuel
composition comprising a fatty acid alkyl ester.
Inventors: |
MATTHEWS; Sarah Jane; (Ince,
Chester, GB) ; SOUTHBY; Mark Clift; (Ince, Chester,
GB) ; XU; Zhou; (Katy, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHELL OIL COMPANY |
Houston |
TX |
US |
|
|
Family ID: |
50277199 |
Appl. No.: |
14/772417 |
Filed: |
March 6, 2014 |
PCT Filed: |
March 6, 2014 |
PCT NO: |
PCT/EP2014/054327 |
371 Date: |
September 3, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61773413 |
Mar 6, 2013 |
|
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|
Current U.S.
Class: |
508/459 |
Current CPC
Class: |
C10N 2030/78 20200501;
C10M 2209/084 20130101; C10N 2030/02 20130101; C10L 2200/0476
20130101; C10N 2020/02 20130101; C10N 2040/253 20200501; C10M
129/68 20130101; C10M 2205/02 20130101; C10M 2205/028 20130101;
C10M 2209/086 20130101; C10L 1/026 20130101; C10N 2030/74 20200501;
C10M 171/02 20130101; C10M 2205/04 20130101; C10L 2270/026
20130101; C10M 2205/173 20130101 |
International
Class: |
C10M 129/68 20060101
C10M129/68; C10L 1/02 20060101 C10L001/02 |
Claims
1. A method of operating an internal combustion engine comprising:
lubricating a crankcase of the internal combustion engine with a
lubricating composition comprising a comb polymer, and using a fuel
composition comprising a fatty acid alkyl ester to fuel the
internal combustion engine.
2. The method according to claim 1 wherein the viscosity of the
lubricating composition is the kinematic viscosity at 100.degree.
C. measured using ASTM D445.
3. The method according to claim 1 wherein the fatty acid alkyl
ester is a fatty acid methyl ester.
4. The method according to claim 1 wherein the comb polymer
comprises, in the main chain, at least one repeat unit which is
obtained from at least one polyolefin-based macromonomer, and at
least one repeat unit which is obtained from at least one low
molecular weight monomer selected from the group consisting of
styrene monomers having 8 to 17 carbon atoms, alkyl (meth)acrylates
having 1 to 10 carbon atoms in the alcohol group, vinyl esters
having from 1 to 11 carbon atoms in the acyl group, vinyl ethers
having 1 to 10 carbon atoms in the alcohol group, (di)alkyl
fumurates having 1 to 10 carbon atoms in the alcohol group,
(di)alkyl maleates having 1 to 10 carbon atoms in the alcohol group
and mixtures thereof, where the molar degree of branching is in the
range of 0.1 to 10 mol % and the comb polymer comprises a total of
at least 80% by weight, based on the total weight of repeat units
of the comb polymer, of the at least one repeat unit which is
obtained from the at least one polyolefin-based macromonomer and
the at least one repeat unit which is obtained from the at least
one low molecular weight monomer.
5. The method according to claim 4 wherein the comb polymer has 11
to 26% by weight of the at least one repeat unit which is obtained
from the at least one polyolefin-based macromonomer.
6. The method according to claim 4 wherein the at least one repeat
unit which is obtained from the at least one polyolefin-based
macromonomer has a number-average molecular weight in the range of
700 to 10000 g/mol.
7. The method according to claim 4 wherein the comb polymer
comprises at least 90% by weight of repeat units which are obtained
from at least one polyolefin-based macromonomer and from at least
one low molecular weight monomer selected from the group consisting
of styrene monomers having 8 to 17 carbon atoms, alkyl
(meth)acrylates having 1 to 10 carbon atoms in the alcohol group,
vinyl esters having from 1 to 11 carbon atoms in the acyl group,
vinyl ethers having 1 to 10 carbon atoms in the alcohol group,
(di)alkyl fumurates having 1 to 10 carbon atoms in the alcohol
group, (di)alkyl maleates having 1 to 10 carbon atoms in the
alcohol group and mixtures thereof.
8. The method according to claim 4 wherein the polydispersity index
Mw/Mn is in the range of from 1 to 5.
9. The method according to claim 4 wherein the molar degree of
branching of the comb polymer is in the range of from 0.4% to
1.0%.
10. The method according to claim 4 wherein the at least one repeat
unit obtained from the at least one polyolefin-based macromonomer
comprises a group, preferably at a level of at least 80% by weight
of the at least one repeat unit obtained from the at least one
polyolefin-based macromonomer, which is obtained from monomers
selected from the group consisting of C2-C10 alkenes and C4-C10
alkadienes.
11. The method according to claim 4 wherein the melting point of
the at least one repeat unit obtained from the at least one
polyolefin-based macromonomers is less than or equal to 10.degree.
C.
12. The method according to claim 4 wherein no melting point of the
at least one repeat unit obtained from the at least one
polyolefin-based macromonomer is measured.
13. The method according to claim 4 wherein the comb polymer has
repeat units that are obtained from at least one or n butyl
methacrylate and n butyl acrylate.
14. The method according to claim 4 wherein the comb polymer has
repeat units which are obtained from styrene.
15. The method according to claim 4 wherein the comb polymer has a
weight-average molecular weight in the range of 100,000 to 500,000
g/mol.
16. The method according to claim 4 wherein the comb polymer has
repeat units which are obtained from alkyl (meth)acrylates having
11-30 carbon atoms in the alkyl radical.
17. The method according to claim 1 wherein the lubricating
composition comprises from 0.1 wt % to 10 wt % of the comb polymer,
by weight of the lubricating composition.
18. The method according to claim 1 wherein the lubricating
composition comprises a base oil and one or more additives.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a lubricating composition
for particular use in the crankcase of an internal combustion
engine, wherein the internal combustion engine is fuelled by
biodiesel.
BACKGROUND OF THE INVENTION
[0002] Government regulations and market demands continue to
emphasize conservation of fossil fuels in the transportation
industry. There is therefore an increasing demand for vehicles
which are fuelled with fuels from renewable or bio-derived
sources.
[0003] It is known to include fatty acid alkyl esters (FAMEs), in
particular fatty acid methyl esters (FAMEs), in diesel fuel
compositions. FAME is produced via a chemical process called
transesterification with methanol in the presence of a catalyst to
yield methyl esters. FAME can be produced from various oil-derived
feedstocks such as soybean, rapeseed, sunflower seed, coconut and
used vegetable oils. FAMEs may be added for a variety of reasons,
including to reduce the environmental impact of the fuel production
and consumption process or to improve lubricity.
[0004] However, it has been found that the lubricant compositions
used for lubricating an internal combustion engine can often become
diluted with the biofuel composition which is used to fuel the
engine. In particular, it has been found that dilution of a
lubricating composition with a FAAE, such as a FAME, can lead to an
undesirable loss in viscosity of the lubricating composition such
that the lubricating composition no longer meets a defined
viscosity grade and/or no longer provides the lubrication
protection for the engine.
[0005] US2010/0190671 relates to the use of comb polymers for
reducing fuel consumption. In particular, the comb polymer
disclosed therein comprises, in the main chain, at least one repeat
unit which is obtained from at least one polyolefin-based
macromonomer, and at least one repeat unit which is obtained from
at least one low molecular weight monomer selected from the group
consisting of styrene monomers having 8 to 17 carbon atoms,
alkyl(meth)acrylates having 1 to 10 carbon atoms in the alcohol
group, vinyl esters having from 1 to 11 carbon atoms in the acyl
group, vinyl ethers having 1 to 10 carbon atoms in the alcohol
group, (di)alkyl fumurates having 1 to 10 carbon atoms in the
alcohol group, (di)alkyl maleates having 1 to 10 carbon atoms in
the alcohol group and mixtures thereof, where the molar degree of
branching is in the range of 0.1 to 10 mol % and the comb polymer
comprises a total of at least 80% by weight, based on the total
weight of repeat units of the comb polymer, of the at least one
repeat unit which is obtained from the at least one
polyolefin-based macromonomer and the at least one repeat unit
which is obtained from the at least one low molecular weight
monomer. There is no disclosure in US2010/0190671, however, of the
use of such comb polymers for providing benefits in terms of
reducing viscosity loss of lubricant compositions which have been
diluted with FAAE's such as FAMEs.
SUMMARY OF THE INVENTION
[0006] According to the present invention there is provided the use
of a comb polymer for reducing the loss in viscosity at 100.degree.
C. of a lubricating composition for the crankcase of an internal
combustion engine, wherein the internal combustion engine is
fuelled with a fuel composition which comprises a fatty acid alkyl
ester.
DETAILED DESCRIPTION OF THE INVENTION
[0007] As mentioned above, it is known that a diesel fuel
composition used to fuel a compression ignition engine may
incorporate a fatty acid alkyl ester (FAAE) such as a fatty acid
methyl ester (FAME) as a fuel component. Unfortunately, however,
FAME is much less volatile than conventional diesel so has a much
higher tendency to accumulate in the lubricant relative to
fossil-derived diesel fuel. Consequently, higher levels of FAME in
diesel fuel can lead to higher level of fuel dilution in the
lubricant, which can lead in turn to an undesirable loss in
viscosity of the lubricant.
[0008] As used herein, the term "reducing the loss in viscosity"
means reducing the loss in viscosity which is experienced when a
lubricating composition is diluted with a fatty acid alkyl ester
(FAAE) such as a FAME. In a preferred embodiment, the reduction in
loss in viscosity is at least a 2% reduction in loss in viscosity,
more preferably at least a 5% reduction in loss in viscosity, even
more preferably at least a 10% reduction in loss in viscosity.
[0009] In a preferred embodiment of the present invention, the
viscosity of the lubricating composition is the kinematic viscosity
at 100.degree. C. as measured according to ASTM D445.
[0010] The FAAE will typically be added to the fuel composition as
a blend (i.e. a physical mixture), conveniently before the
composition is introduced into an internal combustion engine or
other system which is to be run on the composition. Other fuel
components and/or fuel additives may also be incorporated into the
composition, either before or after addition of the FAAE and either
before or during use of the composition in a combustion system.
[0011] The amount of FAAE added will depend on the nature of the
base fuel and FAAE in question and on the target cetane number. In
general, the volume fraction v of FAAE in the resultant base
fuel/FAAE mixture will be less than the volume fraction v' which
would be required if linear blending rules applied, wherein v'
would be defined by the equation:
X=A+v'(B-A).
[0012] The volume fractions v and v' must each have a value between
0 and 1. When carrying out the method of the present invention the
actual volume fraction of FAAE, v, is preferably at least 0.02
lower than the "linear" volume fraction v', more preferably at
least 0.05 or 0.08 or 0.1 lower, most preferably at least 0.2, 0.3
or 0.5 lower and in cases up to 0.6 or 0.8 lower than v'. In
absolute terms, the actual volume fraction v is preferably 0.25 or
less, more preferably 0.2 or less, yet more preferably 0.15 or 0.1
or 0.07 or less. It may for example be from 0.01 to 0.25,
preferably from 0.05 to 0.25, more preferably from 0.05 or 0.1 to
0.2.
[0013] The concentration of the FAAE in the overall fuel
composition (or at least in the base fuel/FAAE mixture) is
preferably 25% v/v or less, more preferably 20% v/v or less, yet
more preferably 15 or 10 or 7% v/v or less. As a minimum it may be
0.05% v/v or greater, preferably 1% v/v or greater, more preferably
2% or 5% v/v or greater, most preferably 7 or 10% v/v or
greater.
[0014] Fatty acid alkyl esters, of which the most commonly used in
the present context are the methyl esters, are already known as
renewable diesel fuels (so-called "biodiesel" fuels). They contain
long chain carboxylic acid molecules (generally from 10 to 22
carbon atoms long), each having an alcohol molecule attached to one
end. Organically derived oils such as vegetable oils (including
recycled vegetable oils) and animal fats can be subjected to a
transesterification process with an alcohol (typically a C.sub.1 to
C.sub.5 alcohol) to form the corresponding fatty esters, typically
mono-alkylated. This process, which is suitably either acid- or
base-catalysed, such as with the base KOH, converts the
triglycerides contained in the oils into fatty acid esters and free
glycerol, by separating the fatty acid components of the oils from
their glycerol backbone.
[0015] In the present invention, the FAAE may be any alkylated
fatty acid or mixture of fatty acids. Its fatty acid component(s)
are preferably derived from a biological source, more preferably a
vegetable source. They may be saturated or unsaturated; if the
latter, they may have one or more double bonds. They may be
branched or un-branched. Suitably they will have from 10 to 30,
more suitably from 10 to 22 or from 12 to 22, carbon atoms in
addition to the acid group(s) --CO.sub.2H. A FAAE will typically
comprise a mixture of different fatty acid esters of different
chain lengths, depending on its source. For instance the commonly
available rapeseed oil contains mixtures of palmitic acid
(C.sub.16), stearic acid (C.sub.18), oleic, linoleic and linolenic
acids (C.sub.18, with one, two and three unsaturated carbon-carbon
bonds respectively) and sometimes also erucic acid (C.sub.22)--of
these the oleic and linoleic acids form the major proportion.
Soybean oil contains a mixture of palmitic, stearic, oleic,
linoleic and linolenic acids. Palm oil usually contains a mixture
of palmitic, stearic and linoleic acid components.
[0016] The FAAE used in the present invention is preferably derived
from a natural fatty oil, for instance a vegetable oil such as
rapeseed oil, soybean oil, coconut oil, sunflower oil, palm oil,
peanut oil, linseed oil, camelina oil, safflower oil, babassu oil,
tallow oil or rice bran oil. It may in particular be an alkyl ester
(suitably the methyl ester) of rapeseed, soy, coconut or palm
oil.
[0017] The FAAE is preferably a C.sub.1 to C.sub.5 alkyl ester,
more preferably a methyl, ethyl or propyl (suitably isopropyl)
ester, yet more preferably a methyl or ethyl ester and in
particular a methyl ester.
[0018] It may for example be selected from the group consisting of
rapeseed methyl ester (RME, also known as rape oil methyl ester or
rape methyl ester), soy methyl ester (SME, also known as soybean
methyl ester), palm oil methyl ester (POME), coconut methyl ester
(CME) (in particular unrefined CME; the refined product is based on
the crude but with some of the higher and lower alkyl chains
(typically the C.sub.6, C.sub.8, C.sub.10, C.sub.16 and C.sub.18)
components removed) and mixtures thereof. In general it may be
either natural or synthetic, refined or unrefined ("crude").
[0019] The FAAE suitably complies with specifications applying to
the rest of the fuel composition, and/or to the base fuel to which
it is added, bearing in mind the intended use to which the
composition is to be put (for example, in which geographical area
and at what time of year). In particular, the FAAE preferably has a
flash point (IP 34) of greater than 101.degree. C.; a kinematic
viscosity at 40.degree. C. (IP 71) of 1.9 to 6.0 centistokes,
preferably 3.5 to 5.0 centistokes; a density from 845 to 910
kg/m.sup.3, preferably from 860 to 900 kg/m.sup.3, at 15.degree. C.
(IP 365, EN ISO 12185 or EN ISO 3675); a water content (IP 386) of
less than 500 ppm; a T95 (the temperature at which 95% of the fuel
has evaporated, measured according to IP 123) of less than
360.degree. C.; an acid number (IP 139) of less than 0.8 mgKOH/g,
preferably less than 0.5 mgKOH/g; and an iodine number (IP 84) of
less than 125, preferably less than 120 or less than 115, grams of
iodine (I.sub.2) per 100 g of fuel. It also preferably contains
(eg, by NMR) less than 0.2% w/w of free methanol, less than 0.02%
w/w of free glycerol and greater than 96.5% w/w esters. In general
it may be preferred for the FAAE to conform to the European
specification EN 14214 for fatty acid methyl esters for use as
diesel fuels.
[0020] The measured cetane number of the FAAE (ASTM D613) is
suitably 55 or greater, preferably 58 or 60 or 65 or even 70 or
greater.
[0021] Two or more FAAEs may be added to the base fuel in
accordance with the present invention, either separately or as a
pre-prepared blend, so long as their combined effect is to increase
the cetane number of the resultant composition to reach the target
number X. In this case the total amount x' of the two or more FAAEs
must be less than the amount of that same combination of FAAEs
which would need to be added to the base fuel in order to achieve
the target cetane number X if linear blending rules applied for
both or all of the FAAEs.
[0022] The FAAE preferably comprises (i.e. either is or includes)
RME or SME.
[0023] The FAAE may be added to the fuel composition for one or
more other purposes in addition to the desire to increase cetane
number, for instance to reduce life cycle greenhouse gas emissions,
to improve lubricity and/or to reduce costs.
[0024] The lubricating composition herein typically comprises a
base oil and one or more additives, in addition to one or more comb
polymers.
[0025] There are no particular limitations regarding the base oil
used in the lubricating compositions herein, and various
conventional mineral oils, synthetic oils as well as naturally
derived esters such as vegetable oils may be conveniently used.
[0026] The base oil used in the present invention may conveniently
comprise mixtures of one or more mineral oils and/or one or more
synthetic oils; thus, the term "base oil" herein may refer to a
blend containing more than one base oil.
[0027] Suitable base oils for use in the lubricating oil
composition of the present invention are Group I-III mineral base
oils (preferably Group III), Group IV poly-alpha olefins (PAOs),
Group II-III Fischer-Tropsch derived base oils (preferably Group
III), Group V base oils, and mixtures thereof.
[0028] By "Group I", "Group II" "Group III" and "Group IV" and
"Group V" base oils in the present invention are meant lubricating
oil base oils according to the definitions of American Petroleum
Institute (API) for categories I, II, III, IV and V. These API
categories are defined in API Publication 1509, 15th Edition,
Appendix E, April 2002.
[0029] Mineral oils include liquid petroleum oils and
solvent-treated or acid-treated mineral lubricating oil of the
paraffinic, naphthenic, or mixed paraffinic/naphthenic type which
may be further refined by hydrofinishing processes and/or
dewaxing.
[0030] A preferred base oil for use in the lubricating compositions
herein is a Fischer-Tropsch derived base oil. Fischer-Tropsch
derived base oils are known in the art. By the term
"Fischer-Tropsch derived" is meant that a base oil is, or is
derived from, a synthesis product of a Fischer-Tropsch process. A
Fischer-Tropsch derived base oil may also be referred to as a GTL
(Gas-To-Liquids) base oil. Suitable Fischer-Tropsch derived base
oils that may be conveniently used as the base oil in the
lubricating composition of the present invention are those as for
example disclosed in EP 0 776 959, EP 0 668 342, WO 97/21788, WO
00/15736, WO 00/14188, WO 00/14187, WO 00/14183, WO 00/14179, WO
00/08115, WO 99/41332, EP 1 029 029, WO 01/18156 and WO
01/57166.
[0031] Typically, the aromatics content of a Fischer-Tropsch
derived base oil, suitably determined by ASTM D 4629, will
typically be below 1 wt. %, preferably below 0.5 wt. % and more
preferably below 0.1 wt. %. Suitably, the base oil has a total
paraffin content of at least 80 wt. %, preferably at least 85, more
preferably at least 90, yet more preferably at least 95 and most
preferably at least 99 wt. %. It suitably has a saturates content
(as measured by IP-368) of greater than 98 wt. %. Preferably the
saturates content of the base oil is greater than 99 wt. %, more
preferably greater than 99.5 wt. %. It further preferably has a
maximum n-paraffin content of 0.5 wt. %. The base oil preferably
also has a content of naphthenic compounds of from 0 to less than
20 wt. %, more preferably of from 0.5 to 10 wt. %.
[0032] Typically, when present in the lubricating compositions
herein, the Fischer-Tropsch derived base oil or base oil blend has
a kinematic viscosity at 100.degree. C. (as measured by ASTM D
7042) in the range of from 1 to 30 mm.sup.2/s (cSt), preferably
from 1 to 25 mm.sup.2/s (cSt), and more preferably from 2
mm.sup.2/s to 12 mm.sup.2/s. Preferably, the Fischer-Tropsch
derived base oil has a kinematic viscosity at 100.degree. C. (as
measured by ASTM D 7042) of at least 2.5 mm.sup.2/s, more
preferably at least 3.0 mm.sup.2/s. In one embodiment of the
present invention, the Fischer-Tropsch derived base oil has a
kinematic viscosity at 100.degree. C. of at most 5.0 mm.sup.2/s,
preferably at most 4.5 mm.sup.2/s, more preferably at most 4.2
mm.sup.2/s (e.g. "GTL 4"). In another embodiment of the present
invention, the Fischer-Tropsch derived base oil has a kinematic
viscosity at 100.degree. C. of at most 8.5 mm.sup.2/s, preferably
at most 8 mm.sup.2/s (e.g. "GTL 8").
[0033] Further, the Fischer-Tropsch derived base oil when present
in the lubricating composition herein typically has a kinematic
viscosity at 40.degree. C. (as measured by ASTM D 7042) of from 10
to 100 mm.sup.2/s (cSt), preferably from 15 to 50 mm.sup.2/s.
[0034] Also, a preferred Fischer-Tropsch derived base oil for use
herein has a pour point (as measured according to ASTM D 5950) of
below -30.degree. C., more preferably below -40.degree. C., and
most preferably below -45.degree. C.
[0035] The flash point (as measured by ASTM D92) of the
Fischer-Tropsch derived base oil is preferably greater than
120.degree. C., more preferably even greater than 140.degree.
C.
[0036] A preferred Fischer-Tropsch derived base oil for use herein
has a viscosity index (according to ASTM D 2270) in the range of
from 100 to 200. Preferably, the Fischer-Tropsch derived base oil
has a viscosity index of at least 125, preferably 130. Also it is
preferred that the viscosity index is below 180, preferably below
150.
[0037] In the event the Fischer-Tropsch derived base oil contains a
blend of two or more Fischer-Tropsch derived base oils, the above
values apply to the blend of the two or more Fischer-Tropsch
derived base oils.
[0038] The lubricating oil composition herein preferably comprises
80 wt % or greater of Fischer-Tropsch derived base oil.
[0039] Synthetic oils include hydrocarbon oils such as olefin
oligomers (including polyalphaolefin base oils; PAOs), dibasic acid
esters, polyol esters, polyalkylene glycols (PAGs), alkyl
naphthalenes and dewaxed waxy isomerates. Synthetic hydrocarbon
base oils sold by the Shell Group under the designation "Shell
XHVI" (trade mark) may be conveniently used.
[0040] Poly-alpha olefin base oils (PAOs) and their manufacture are
well known in the art. Preferred poly-alpha olefin base oils that
may be used in the lubricating compositions of the present
invention may be derived from linear C.sub.2 to C.sub.32,
preferably C.sub.6 to C.sub.16, alpha olefins. Particularly
preferred feedstocks for said poly-alpha olefins are 1-octene,
1-decene, 1-dodecene and 1-tetradecene.
[0041] There is a strong preference for using a Fischer-Tropsch
derived base oil over a PAO base oil, in view of the high cost of
manufacture of the PAOs. Thus, preferably, the base oil contains
more than 50 wt. %, preferably more than 60 wt. %, more preferably
more than 70 wt. %, even more preferably more than 80 wt. %. most
preferably more than 90 wt. % Fischer-Tropsch derived base oil. In
an especially preferred embodiment not more than 5 wt. %,
preferably not more than 2 wt. %, of the base oil is not a
Fischer-Tropsch derived base oil. It is even more preferred that
100 wt % of the base oil is based on one or more Fischer-Tropsch
derived base oils.
[0042] The total amount of base oil incorporated in the lubricating
composition of the present invention is preferably in the range of
from 60 to 99 wt. %, more preferably in the range of from 65 to 90
wt. % and most preferably in the range of from 70 to 85 wt. %, with
respect to the total weight of the lubricating composition.
[0043] Typically the base oil (or base oil blend) as used according
to the present invention has a kinematic viscosity at 100.degree.
C. (according to ASTM D445) of above 2.5 cSt and up to 8 cSt.
According to a preferred embodiment of the present invention the
base oil has a kinematic viscosity at 100.degree. C. (according to
ASTM D445) of between 3.5 and 8 cSt. In the event the base oil
contains a blend of two or more base oils, it is preferred that the
blend has a kinematic viscosity at 100.degree. C. of between 3.5
and 7.5 cSt.
[0044] The lubricating composition herein preferably has a Noack
volatility (according to ASTM D 5800) of below 15 wt. %. Typically,
the Noack volatility (according to ASTM D 5800) of the composition
is between 1 and 15 wt. %, preferably below 14.6 wt. % and more
preferably below 14.0 wt. %.
[0045] The lubricating composition herein comprises one or more
comb polymers, preferably in a solid polymer amount of from 0.1 wt
% to 10 wt %, more preferably from 0.25 wt % to 7 wt %, and even
more preferably from 0.5 wt % to 4 wt %, and especially from 0.5 wt
% to 2 wt %, by weight of the total lubricating composition.
[0046] The comb polymer is used herein preferably as a VI
Improver.
[0047] Preferably for use herein the comb polymer comprises, in the
main chain, at least one repeat unit which is obtained from at
least one polyolefin-based macromonomer, and at least one repeat
unit which is obtained from at least one low molecular weight
monomer selected from the group consisting of styrene monomers
having 8 to 17 carbon atoms, alkyl(meth)acrylates having 1 to 10
carbon atoms in the alcohol group, vinyl esters having from 1 to 11
carbon atoms in the acyl group, vinyl ethers having 1 to 10 carbon
atoms in the alcohol group, (di)alkyl fumurates having 1 to 10
carbon atoms in the alcohol group, (di)alkyl maleates having 1 to
10 carbon atoms in the alcohol group and mixtures thereof, where
the molar degree of branching is in the range of 0.1 to 10 mol %
and the comb polymer comprises a total of at least 80% by weight,
based on the total weight of repeat units of the comb polymer, (or
in another aspect based on the total weight of the comb polymer),
of the at least one repeat unit which is obtained from the at least
one polyolefin-based macromonomer and the at least one repeat unit
which is obtained from the at least one low molecular weight
monomer.
[0048] Preferably, the comb polymer used herein has 8% to 30% by
weight of repeat units which are derived from polyolefin-based
macromonomers, and the molar degree of branching of the comb
polymer is in the range of 0.3% to 1.1%.
[0049] The term "comb polymer" as used herein means that relatively
long side chains are bonded to a polymeric main chain, frequently
also known as the backbone. The comb polymers used in the present
invention have at least one repeat unit which is derived from
polyolefin-based macromonomers. The term "main chain" as used
herein does not necessarily mean that the chain length of the main
chain is greater than that of the side chains. Instead, this term
relates to the composition of this chain. While the side chain has
very high proportions of olefinic repeat units, especially units
which are derived from alkenes or alkadienes, for example ethylene,
propylene, n-butene, isobutene, butadiene, isoprene, the main chain
comprises relatively large proportions of polar unsaturated
monomers which have been detailed above.
[0050] The term "repeat unit" is known to those skilled in the art.
The present comb polymers can be obtained by a process which
involves the free-radical polymerisation of macromonomers and low
molecular weight monomers, wherein double bonds are opened up to
form covalent bonds. Accordingly, the repeat unit arises from the
monomers used. However, the comb polymers can also be prepared by
polymer-analagous reactions and graft copolymerisation. In this
case, the converted repeat unit of the main chain is counted as a
repeat unit which is derived from a polyolefin-based
macromonomer.
[0051] Further details of preparation methods of the comb polymers
use herein can be found in US2010/0190671 and US2008/0194443, which
are incorporated herein by reference.
[0052] The comb polymers used in the present invention comprise
repeat units which are derived from polyolefin-based macromonomers.
These repeat units comprise are least one group which is derived
from polyolefins. Examples of suitable polyolefins include C2-C10
alkenes, such as ethylene, propylene, n-butene, isobutene,
norbornene, and/or C4-C10 alkadienes such as butadiene, isoprene,
norbornadiene, and the like.
[0053] The repeat units derived from polyolefin-based macromonomers
preferably comprise at least 70% by weight and more preferably at
least 80% by weight and most preferably at least 90% by weight of
groups which are derived from alkene and/or alkadienes, based on
the weight of the repeat units derived from polyolefin-based
macromonomers.
[0054] The polymeric groups may also be present in hydrogenated
form. In addition to the groups which are derived from alkenes
and/or alkadienes, the repeat units derived from polyolefin-based
macromonomers may comprise further groups. These include small
proportions of copolymerizable monomers, including among others,
alkyl (meth)acrylates, styrene monomers, fumurates, maleates, vinyl
esters and/or vinyl ethers. The proportion of these groups based on
copolymerizable monomers is preferably at most 30% by weight, more
preferably at most 15% by weight, based on the weight of the repeat
units derived from polyolefin-based macromonomers. The repeat units
derived from polyolefin-based macromonomers may comprise start
groups and/or end groups which serve from functionalization or are
caused by the preparation of the repeat units derived from
polyolefin-based macromonomers. The proportion of these start
groups and/or end groups is preferably at most 30% by weight, more
preferably at most 15% by weight, based on the weight of the repeat
units derived from polyolefin-based macromonomers.
[0055] The number-average molecular weight of the repeat units
which are derived from polyolefin-based macromonomers is preferably
in the range from 500 to 50000 g/mol, more preferably from 700 to
10000 g/mol, even more preferably from 1500 to 4900 g/mol and most
preferably from 2000 to 3000 g/mol.
[0056] The melting point of the repeat units derived from the
polyolefin-based macromonomers is preferably less than or equal to
-10.degree. C., more preferably less than or equal to -20.degree.
C., even more preferably less than or equal to -40.degree. C., as
measured by DSC. Most preferably, no DSC melting point can be
measured for the repeat units derived from the polyolefin-based
macromonomers.
[0057] In addition to the repeat units which are derived from the
polyolefin-based macromonomers, the comb polymers used in the
present invention comprise repeat units which are derived from low
molecular weight monomers selected from the group consisting of
styrene monomers having 8 to 17 carbon atoms, alkyl(meth)acrylates
having 1 to 10 carbon atoms in the alcohol group, vinyl esters
having 1 to 11 carbon atoms in the acyl group, vinyl ethers having
1 to 10 carbon atoms in the alcohol group, di(alkyl) fumurates
having 1 to 10 carbon atoms in the alcohol group, (di)alkyl
maleates having 1 to 10 carbon atoms in the alcohol group, and
mixtures of these monomers.
[0058] The molecular weight of the low molecular weight repeat
units or of the low molecular weight monomers is preferably at most
400 g/mol, more preferably at most 200 g/mol and most preferably at
most 150 g/mol.
[0059] Examples of styrene monomers having 8 to 17 carbon atoms are
styrene, substituted styrenes having an alkyl substituent in the
side chain, for example, alpha-methylstyrene and
alpha-ethyl-styrene, substituted styrenes having an alkyl
substituent on the ring, such as vinyltoluene p-methylstyrene,
halogenated styrenes, for example monochlorostyrenes,
dichlorostyrenes, tribromostyrenes, and tetrabromostyrenes.
[0060] The term "(meth)acrylates" encompasses acrylates and
methacrylates, and also mixtures of acrylates and methacrylates.
The alkyl (meth)acrylates having 1 to 10 carbon atoms in the
alcohol group include (meth)acrylates which derived from saturated
alcohols, such as methyl(meth)acrylate, ethyl(meth)acrylate,
n-propyl(meth)acrylate, isopropyl(meth)acrylate,
n-butyl(meth)acrylate, tert-butyl(meth)acrylate,
pentyl(meth)acrylate, hexyl(meth)acrylate,
2-ethyl-hexyl(meth)acrylate, heptyl(meth)acrylate,
2-tert-butylheptyl(meth)acrylate, octyl(meth)acrylate,
3-isopropylheptyl(meth)acrylate, nonyl(meth)acrylate,
decyl(meth)acrylate; (meth)acrylates which derive from unsaturated
alcohols, for example 2-propynyl (meth)acrylate,
allyl(meth)acrylate, vinyl(meth)acrylate, oleyl(meth(acrylate;
cycloalkyl(meth(acrylates such as cyclpentyl(meth)acrylate, and
3-vinylcyclohexyl(meth)acrylate.
[0061] Preferred alkyl(meth)acrylates include 1 to 8, more
preferably 1 to 4 carbon atoms in the alcohol group. The alcohol
group here may be linear or branched.
[0062] Examples of vinyl esters having 1 to 11 carbon atoms in the
acyl group include vinyl formate, vinyl acetate, vinyl propionate,
vinyl butyrate. Preferred vinyl esters include 2 to 9, more
preferably 2 to 5 carbon atoms in the acyl group. The acyl group
may be linear or branched.
[0063] Examples of vinyl ethers having 1 to 10 carbon atoms in the
alcohol group include vinyl methyl ether, vinyl ethyl ether, vinyl
propyl ether, vinyl butyl ether. Preferred vinyl ethers include 1
to 8, more preferably 1 to 4 carbon atoms in the alcohol group. The
alcohol group may be linear or branched.
[0064] The term "(di)ester" as used herein means that monoesters,
diesters and mixtures of esters, especially of fumaric acid and/or
of maleic acid may be used. The (di)alkyl fumurates having 1 to 10
carbon atoms in the alcohol group include monomethyl fumurate,
dimethyl fumurate, monoethyl fumurate, diethyl fumurate, methyl
ethyl fumurate, monobutyl fumurate, dibutyl fumurate, dipentyl
fumurate and dihexyl fumurate. Preferred (di)alkyl fumurates
comprise 1 to 8, more preferably 1 to 4, carbon atoms in the
alcohol group. The alcohol group may be linear or branched.
[0065] The di(alkyl) maleates having 1 to 10 carbon atoms in the
alcohol group include monomethyl maleate, dimethyl maleate,
monoethyl maleate, diethyl maleate, methyl ethyl maleate, monobutyl
maleate, dibutyl maleate. Preferred (di)alkyl maleates comprise 1
to 8, more preferably 1 to 4 carbon atoms in the alcohol group. The
alcohol group herein may be linear or branched.
[0066] In addition to the repeat units detailed above, the comb
polymers used herein may comprise further repeat units which are
derived from further comonomers, their proportion being at most 20%
by weight, preferably at most 10% by weight and more preferably at
most 5% by weight, based on the weight of the repeat units.
[0067] These also include repeat units which are derived from
alkyl(meth)acrylates having 11 to 30 carbon atoms in the alcohol
group, especially 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,
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)acrylate and/or
eicosyltetratriacontyl(meth)acrylate.
[0068] The comb polymers used herein preferably have a molar degree
of branching in the range of from 0.1 to 10 mol %, more preferably
from 0.3 to 6 mol %, even more preferably from 0.3 to 1.1 mol %,
especially from 0.4 to 1.0 mol % and most preferably from 0.4 to
0.6 mol %. Details of how the molar degree of branching is
calculated can be found in US2010/0190671 and US2008/0194443, which
are incorporated herein by reference.
[0069] The comb polymer used herein preferably has 8 to 30% by
weight, more preferably 10 to 26% by weight, of repeat units which
are derived from polyolefin-based macromonomers, based on the total
weight of the repeat units.
[0070] Preferred comb polymers for use herein include those which
have a weight average molecular weight Mw in the range of 500,000
to 1,000,000 g/mol, more preferably 100,000 to 500,000 g/mol and
most preferably 150,000 to 450,000 g/mol.
[0071] The number-average molecular weight Mn, may preferably be in
the range of 20,000 to 800,000 g/mol, more preferably 40,000 to
200,000 g/mol and most preferably 50,000 to 150,000 g/mol.
[0072] Preferably the comb polymers used herein have a
polydipersity index Mw/Mn in the range of 1 to 5, more preferably
in the range of from 2.5 to 4.5. The number average and the weight
average molecular weight can be determined by known processes such
as Gas Permeation Chromatography (GPC).
[0073] In a preferred embodiment herein the comb polymer has repeat
units which are derived from n-butyl methacrylate and/or from
n-butyl acrylate. Preferably, the proportion of repeat units which
are derived from n-butyl methacrylate and/or from n-butyl acrylate
is at least 50% by weight, more preferably at least 60% by weight,
based on the total weight of repeat units.
[0074] In a preferred embodiment herein the comb polymer has repeat
units which are derived from styrene. The proportion of repeat
units which are derived from styrene are preferably in the range of
0.1 to 30% by weight, more preferably 5 to 25% by weight.
[0075] In a preferred embodiment herein, the comb polymers have
repeat units which are derived from alkyl(meth)acrylate having
11-30 carbon atoms in the alkyl radical, preferably in an amount in
the range of 0.1% to 15% by weight, more preferably in the range of
1 to 10% by weight.
[0076] In a preferred embodiment herein the comb polymer has repeat
units which are derived from styrene and repeat units which are
derived from n-butyl methacrylate. The weight ratio of styrene
repeat units and n-butylmethacrylate repeat units is preferably in
the range of 1:1 to 1:9, more preferably 1:2 to 1:8.
[0077] In another preferred embodiment, the comb polymer has repeat
units which are derived from methyl methacrylate and repeat units
which are derived from n-butyl methacrylate in a weight ratio of
1:1 to 0:100, more preferably 3:7 to 0:100.
[0078] A commercially available comb polymer suitable for use
herein is available from Evonik under the tradename Viscoplex
3-201.
[0079] The lubricating composition herein further comprises one or
more additives such as anti-oxidants, anti-wear additives,
dispersants, detergents, overbased detergents, extreme pressure
additives, friction modifiers, viscosity index improvers, pour
point depressants, metal passivators, corrosion inhibitors,
demulsifiers, anti-foam agents, seal compatibility agents and
additive diluent base oils, etc.
[0080] As the person skilled in the art is familiar with the above
and other additives, these are not further discussed here in
detail. Specific examples of such additives are described in for
example Kirk-Othmer Encyclopedia of Chemical Technology, third
edition, volume 14, pages 477-526.
[0081] Anti-oxidants that may be conveniently used include
phenyl-naphthylamines (such as "IRGANOX L-06" available from Ciba
Specialty Chemicals) and diphenylamines (such as "IRGANOX L-57"
available from Ciba Specialty Chemicals) as e.g. disclosed in WO
2007/045629 and EP 1 058 720 B1, phenolic anti-oxidants, etc. The
teaching of WO 2007/045629 and EP 1 058 720 B1 is hereby
incorporated by reference.
[0082] Anti-wear additives that may be conveniently used include
zinc-containing compounds such as zinc dithiophosphate compounds
selected from zinc dialkyl-, diaryl- and/or
alkylaryl-dithiophosphates, molybdenum-containing compounds,
boron-containing compounds and ashless anti-wear additives such as
substituted or unsubstituted thiophosphoric acids, and salts
thereof.
[0083] Examples of such molybdenum-containing compounds may
conveniently include molybdenum dithiocarbamates, trinuclear
molybdenum compounds, for example as described in WO 98/26030,
sulphides of molybdenum and molybdenum dithiophosphate.
[0084] Boron-containing compounds that may be conveniently used
include borate esters, borated fatty amines, borated epoxides,
alkali metal (or mixed alkali metal or alkaline earth metal)
borates and borated overbased metal salts.
[0085] The dispersant used is preferably an ashless dispersant.
Suitable examples of ashless dispersants are polybutylene
succinimide polyamines and Mannich base type dispersants.
[0086] The detergent used is preferably an overbased detergent or
detergent mixture containing e.g. salicylate, sulphonate and/or
phenate-type detergents.
[0087] Examples of viscosity index improvers, in addition to the
one or more comb polymers, which may conveniently be used in the
lubricating composition of the present invention include the
styrene-butadiene stellate copolymers, styrene-isoprene stellate
copolymers and the polymethacrylate copolymer and
ethylene-propylene copolymers (also known as olefin copolymers) of
the crystalline and non-crystalline type. Dispersant-viscosity
index improvers may be used in the lubricating composition of the
present invention. However, preferably the composition according to
the present invention contains less than 1.0 wt. %, preferably less
than 0.5 wt. %, of a Viscosity Index improver concentrate (i.e. VI
improver plus "carrier oil" or "diluent"), based on the total
weight of the composition. Most preferably, the composition is free
of Viscosity Index improver concentrate. The term "Viscosity
Modifier" as used hereafter (such as in Table 2) is meant to be the
same as the above-mentioned term "Viscosity Index improver
concentrate".
[0088] Preferably, the composition contains at least 0.1 wt. % of a
pour point depressant. As an example, alkylated naphthalene and
phenolic polymers, polymethacrylates, maleate/fumarate copolymer
esters may be conveniently used as effective pour point
depressants. Preferably not more than 0.3 wt. % of the pour point
depressant is used.
[0089] Furthermore, compounds such as alkenyl succinic acid or
ester moieties thereof, benzotriazole-based compounds and
thiodiazole-based compounds may be conveniently used in the
lubricating composition herein as corrosion inhibitors.
[0090] Compounds such as polysiloxanes, dimethyl polycyclohexane
and polyacrylates may be conveniently used in the lubricating
composition herein as defoaming agents.
[0091] Compounds which may be conveniently used in the lubricating
composition herein as seal fix or seal compatibility agents
include, for example, commercially available aromatic esters.
[0092] The lubricating compositions herein may be conveniently
prepared by admixing the comb polymer with the base oil(s), and one
or more additives.
[0093] The above-mentioned additives are typically present in an
amount in the range of from 0.01 to 35.0 wt. %, based on the total
weight of the lubricating composition, preferably in an amount in
the range of from 0.05 to 25.0 wt. %, more preferably from 1.0 to
20.0 wt. %, based on the total weight of the lubricating
composition.
[0094] Preferably, the composition contains at least 8.0 wt. %,
preferably at least 10.0 wt. %, more preferably at least 11.0 wt %
of an additive package comprising an anti-wear additive, a metal
detergent, an ashless dispersant, an anti-oxidant, a friction
modifier and an anti-foaming agent.
[0095] The lubricating compositions herein may be so-called "low
SAPS" (SAPS=sulphated ash, phosphorus and sulphur), "mid SAPS" or
"regular SAPS" formulations.
[0096] For Passenger Car Motor Oil (PCMO) engine oils the above
ranges mean: [0097] a sulphated ash content (according to ASTM D
874) of up to 0.5 wt. %, up to 0.8 wt. % and up to 1.5 wt. %,
respectively; [0098] a phosphorus content (according to ASTM D
5185) of up to 0.05 wt. %, up to 0.08 wt. % and typically up to 0.1
wt. %, respectively; and [0099] a sulphur content (according to
ASTM D 5185) of up to 0.2 wt. %, up to 0.3 wt. % and typically up
to 0.5 wt. %, respectively.
[0100] For Heavy Duty Diesel Engine Oils the above ranges mean:
[0101] a sulphated ash content (according to ASTM D 874) of up to 1
wt. %, up to 1 wt. % and up to 2 wt. %, respectively; [0102] a
phosphorus content (according to ASTM D 5185) of up to 0.08 wt. %
(low SAPS) and up to 0.12 wt. % (mid SAPS), respectively; and
[0103] a sulphur content (according to ASTM D 5185) of up to 0.3
wt. % (low SAPS) and up to 0.4 wt. % (mid SAPS), respectively.
[0104] The present invention is described below with reference to
the following Examples, which are not intended to limit the scope
of the present invention in any way.
Examples
Lubricating Oil Compositions
[0105] Various engine oils for use in a crankcase engine were
formulated.
[0106] Table 1 indicates the properties for the base oils used.
Table 2 indicates the composition and properties of the fully
formulated engine oil formulations that were tested; the amounts of
the components are given in wt. %, based on the total weight of the
fully formulated formulations.
[0107] "Base oil 1" was a Fischer-Tropsch derived base oil ("GTL
4") having a kinematic viscosity at 100.degree. C. (ASTM D445) of
approx. 4 cSt (mm.sup.2 s.sup.-1). This GTL 4 base oil may be
conveniently manufactured by the process described in e.g. WO
02/070631, the teaching of which is hereby incorporated by
reference.
[0108] "Base oil 2" was a Fischer-Tropsch derived base oil ("GTL
8") having a kinematic viscosity at 100.degree. C. (ASTM D445) of
approx. 8 cSt (mm.sup.2 s.sup.-1). This GTL 8 base oil may be
conveniently manufactured by the process described in e.g. WO
02/070631, the teaching of which is hereby incorporated by
reference.
[0109] All tested engine oil formulations contained a combination
of a base oil, a comb polymer (or other Viscosity Modifier in the
case of the Comparative Examples) and an additive package. The
additive package was the same in all tested compositions.
[0110] The additive package contained a combination of additives
including anti-oxidants, a zinc-based anti-wear additive, an
ashless dispersant, an overbased detergent mixture and about 10 ppm
of an anti-foaming agent.
[0111] The comb polymer used in Examples 1, 2 and 3 was a
commercially available comb polymer available from Evonik under the
tradename "Viscoplex 3-201".
[0112] The viscosity modifier used in Comparative Examples 1, 4 and
7 was Viscoplex 8-200 which is a conventional PMA
(polymethacrylate) polymer commercially available from Evonik.
[0113] The viscosity modifier used in Comparative Example 2, 5 and
8 was a conventional olefin copolymer available from Lubrizol under
the tradename Lubrizol 7067C.
[0114] The viscosity modifier used in Comparative Example 3, 6 and
9 was a functionalised PMA (polymethacrylate) polymer available
from Evonik under the tradename Viscoplex 6-054.
[0115] The compositions of the Examples and the Comparative
Examples were obtained by mixing the base oils with the other
components, using conventional lubricant blending procedures.
[0116] The kinematic viscosity of 100.degree. C. of each of the
lubricating compositions of the Examples and Comparative Examples
was measured according to ASTM D445. The results of these
measurements are shown in Tables 2, 4 and 6.
[0117] In order to show the effect that each of the viscosity
modifiers have on product viscosity when the lubricating
composition is diluted with FAME, each of the compositions was
diluted with FAME (at a blending ratio of 80 wt % lubricating
composition:20 wt % FAME) and then the kinematic viscosity at
100.degree. C. of each of the diluted lubricating compositions was
measured according to ASTM D445. The results of these tests are
shown in Tables 3, 5 and 7.
TABLE-US-00001 TABLE 1 Base oil 1 Base oil 2 (GTL 4) (GTL 8)
Kinematic 4.0 8 viscosity at 100.degree. C..sup.1 [cSt] VI
Index.sup.2 120 120 Pour point.sup.3 [.degree. C.] -30 -30 Noack
14.0 5 volatility.sup.4 [wt. %] .sup.1According to ASTM D 445.
Average figures quoted .sup.2According to ASTM D 2270. Minimum
values quoted. .sup.3According to ASTM D 5950. Maximum values
quoted. .sup.4According to CEC L-40-A-93/ASTM D 5800. Maximum
values quoted
TABLE-US-00002 TABLE 2 Comp. Comp. Comp. Component [wt. %] Example
1 Example 2 Example 1 Example. 3 Base oil 1 (GTL 4) 10.48 73.5
10.09 16.41 Base oil 2 (GTL 8) 76.0 6.7 73.81 69.73 Viscoplex 8-200
1.42 -- -- -- (polymer treat rate = 1 wt %) Lubrizol 7067C -- 7.7
-- -- (polymer treat rate = 1 wt %) Viscoplex 3-201 -- -- 4.0 --
(polymer treat rate = 1 wt %) Viscoplex 6-054 -- -- -- 1.76
(polymer treat rate = 1 wt %) Additive Package 12.1 12.1 12.1 12.1
TOTAL 100 100 100 100 Properties of the total composition Kinematic
viscosity at 9.495 9.579 9.561 9.498 100.degree. C..sup.1 [cSt]
.sup.1According to ASTM D 445 .sup.2The compositions shown in Table
2 were formulated such that the polymer treat rates were the same
(1 wt %) and such that the kV100 of the compositions were
approximately the same.
TABLE-US-00003 TABLE 3 Comp. Comp. Comp. Component [wt. %] Example
1 Example 2 Example 1 Example. 3 Wt % finished lubricant 80 80 80
80 Wt % FAME 20 20 20 20 TOTAL 100 100 100 100 Properties of the
total composition Kinematic viscosity at 6.414 6.608 6.956 6.426
100.degree. C..sup.1 [cSt] Drop in kV100 after 3.081 2.971 2.605
3.072 adding FAME kV100 drop percentage 32.4% 31.0% 27.2% 32.3%
.sup.1According to ASTM D 445
TABLE-US-00004 TABLE 4 Comp. Comp. Comp. Component [wt. %] Example
4 Example 5 Example 2 Example. 6 Base oil 1 (GTL 4) 3.18 34.92 2.95
6.52 Base oil 2 (GTL 8) 84.01 49.13 82.95 80.5 Viscoplex 8-200 0.71
-- -- -- (polymer treat rate = 0.5 wt %) Lubrizol 7067C -- 3.85 --
-- (polymer treat rate = 0.5 wt %) Viscoplex 3-201 -- -- 2.0 --
(polymer treat rate = 0.5 wt %) Viscoplex 6-054 -- -- -- 0.88
(polymer treat rate = 0.5 wt %) Additive Package 12.1 12.1 12.1
12.1 TOTAL 100 100 100 100 Properties of the total composition
Kinematic viscosity at 9.623 9.608 9.625 9.599 100.degree. C..sup.1
[cSt] .sup.1According to ASTM D 445 .sup.2The compositions shown in
Table 4 were formulated such that the polymer treat rates were the
same (0.5 wt %) and such that the kV100 of the compositions were
approximately the same.
TABLE-US-00005 TABLE 5 Comp. Comp. Comp. Component [wt. %] Example
4 Example 5 Example 2 Example. 6 Wt % finished lubricant 80 80 80
80 Wt % FAME 20 20 20 20 TOTAL 100 100 100 100 Properties of the
total composition Kinematic viscosity at 6.426 6.485 6.678 6.419
100.degree. C..sup.1 [cSt] Drop in kV100 after 3.197 3.123 2.947
6.419 adding FAME kV100 drop percentage 33.2% 32.5% 30.6% 33.1%
.sup.1According to ASTM D 445
TABLE-US-00006 TABLE 6 Comp. Comp. Comp. Component [wt. %] Example
7 Example 8 Example 3 Example. 9 Base oil 1 (GTL 4) 17.42 75.79
16.83 26.32 Base oil 2 (GTL 8) 68.35 0.56 65.07 58.94 Viscoplex
8-200 2.13 -- -- -- (polymer treat rate = 1.5 wt %) Lubrizol 7067C
-- 11.55 -- -- (polymer treat rate = 1.5 wt %) Viscoplex 3-201 --
-- 6.0 -- (polymer treat rate = 1.5 wt %) Viscoplex 6-054 -- -- --
2.64 (polymer treat rate = 1.5 wt %) Additive package 12.1 12.1
12.1 12.1 TOTAL 100 100 100 100 Properties of the total composition
Kinematic viscosity at 9.346 11.81 9.615 9.359 100.degree. C..sup.1
[cSt] .sup.1According to ASTM D 445 .sup.2The compositions shown in
Table 6 were formulated such that the polymer treat rates were the
same (1.5 wt %) and such that the kV100 of the compositions were
approximately the same.
TABLE-US-00007 TABLE 7 Comp. Comp. Comp. Component [wt. %] Example
7 Example 8 Example 3 Example. 9 Wt % finished lubricant 80 80 80
80 Wt % FAME 20 20 20 20 TOTAL 100 100 100 100 Properties of the
total composition Kinematic viscosity at 6.371 7.896 7.422 6.393
100.degree. C..sup.1 [cSt] Drop in kV100 after 2.975 3.914 2.193
2.966 adding FAME kV100 drop percentage 31.8% 33.1% 22.8% 31.7%
.sup.1According to ASTM D 445
Discussion
[0118] The results in Tables 3, 5 and 7 demonstrate that the use of
a comb polymer (Viscoplex 3-201) at a treat rate of 1 wt %, 0.5 wt
% and 1.5 wt % in a lubricating composition reduces the % loss in
kinematic viscosity at 100.degree. C. when the lubricating
composition is diluted with 20 wt % FAME. The Viscoplex 3-201 comb
polymer reduces the % loss in kinematic viscosity at 100.degree. C.
to a greater extent than other (non-comb) viscosity modifier
polymers tested, namely Viscoplex 8-200, Lubrizol 7607C and
Viscoplex 6-054.
[0119] In particular, Example 1 (containing 1 wt % of the comb
polymer Viscoplex 3-201) exhibited a 27.2% loss in kinematic
viscosity at 100.degree. C. when diluted with 20 wt % of FAME. By
comparison, Comparative Example 1 (containing 1 wt % of a
conventional polymethacrylate polymer (Viscoplex 8-200)) exhibited
a 32.4% loss in kinematic viscosity at 100.degree. C. when diluted
with 20 wt % of FAME. Further, Comparative Example 2 (containing a
conventional olefin copolymer (Lubrizol 7067C) exhibits a 31% loss
in kinematic viscosity at 100.degree. C. when diluted with 20 wt %
of FAME. Yet further, Comparative Example 3 (containing a
functionalised polymethacrylate polymer (Viscoplex 6-054) exhibits
a 32.3% loss in kinematic viscosity at 100.degree. C. when diluted
with 20 wt % FAME.
[0120] Further, Example 2 (containing 0.5 wt % of the comb polymer
Viscoplex 3-201) exhibited a 30.6% loss in kinematic viscosity at
100.degree. C. when diluted with 20 wt % of FAME. By comparison,
Comparative Example 4 (containing 0.5 wt % of a conventional
polymethacrylate polymer (Viscoplex 8-200)) exhibited a 33.2% loss
in kinematic viscosity at 100.degree. C. when diluted with 20 wt %
of FAME. Further, Comparative Example 5 (containing a conventional
olefin copolymer (Lubrizol 7067C) exhibits a 32.5% loss in
kinematic viscosity at 100.degree. C. when diluted with 20 wt % of
FAME. Yet further, Comparative Example 6 (containing a
functionalised polymethacrylate polymer (Viscoplex 6-054) exhibits
a 33.1% loss in kinematic viscosity at 100.degree. C. when diluted
with 20 wt % FAME.
[0121] Further, Example 3 (containing 1.5 wt % of the comb polymer
Viscoplex 3-201) exhibited a 22.8% loss in kinematic viscosity at
100.degree. C. when diluted with 20 wt % of FAME. By comparison,
Comparative Example 7 (containing 1.5 wt % of a conventional
polymethacrylate polymer (Viscoplex 8-200)) exhibited a 31.8% loss
in kinematic viscosity at 100.degree. C. when diluted with 20 wt %
of FAME. Further, Comparative Example 8 (containing a conventional
olefin copolymer (Lubrizol 7067C) exhibits a 33.1% loss in
kinematic viscosity at 100.degree. C. when diluted with 20 wt % of
FAME. Yet further, Comparative Example 9 (containing a
functionalised polymethacrylate polymer (Viscoplex 6-054) exhibits
a 31.7% loss in kinematic viscosity at 100.degree. C. when diluted
with 20 wt % FAME.
* * * * *