U.S. patent application number 16/470242 was filed with the patent office on 2019-10-10 for ether-based lubricant compositions, methods and uses.
The applicant listed for this patent is CASTROL LIMITED. Invention is credited to David Gordon LAMB, John Michael REDSHAW, Kevin Richard WEST, Rebecca YATES.
Application Number | 20190309237 16/470242 |
Document ID | / |
Family ID | 60702781 |
Filed Date | 2019-10-10 |
View All Diagrams
United States Patent
Application |
20190309237 |
Kind Code |
A1 |
LAMB; David Gordon ; et
al. |
October 10, 2019 |
Ether-Based Lubricant Compositions, Methods and Uses
Abstract
##STR00001## The present invention provides a lubricant
composition for an internal combustion engine comprising a base oil
of lubricating viscosity, wherein the base oil comprises an ether
base stock of formula (A): where: R.sub.a and R.sub.b are aliphatic
hydrocarbyl groups and may be the same or different; wherein at
least one of R.sub.a and R.sub.b is branched-chain alkyl,
alkoxy-substituted-alkyl or cycloalkyl-substituted-alkyl; the
lubricant composition further comprising: i) at least one
molybdenum compound as a lubricant additive which is present, on a
molybdenum element basis, in an amount of at least 0.06% by weight
of the lubricant composition; or ii) at least one polymethacrylate
compound as a lubricant additive which is present in an amount of
from 0.1 to 7.5% by weight of the lubricant composition. The
lubricant composition may be used for lubricating a surface in an
internal combustion engine as well as for improving the fuel
economy performance and/or piston cleanliness performance and/or
turbocharger cleanliness performance of an engine and/or a vehicle,
such as an automotive vehicle associated with an internal
combustion engine.
Inventors: |
LAMB; David Gordon; (Reading
Berkshire, GB) ; REDSHAW; John Michael; (Reading,
Berkshire, GB) ; WEST; Kevin Richard; (Reading,
Berkshire, GB) ; YATES; Rebecca; (Reading, Berkshire,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CASTROL LIMITED |
Reading |
|
GB |
|
|
Family ID: |
60702781 |
Appl. No.: |
16/470242 |
Filed: |
December 14, 2017 |
PCT Filed: |
December 14, 2017 |
PCT NO: |
PCT/EP2017/082926 |
371 Date: |
June 16, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 2205/0285 20130101;
C10M 2227/066 20130101; C10M 2203/1025 20130101; C10N 2030/10
20130101; C10N 2030/02 20130101; C10N 2030/08 20130101; C10M
2207/04 20130101; C10N 2030/74 20200501; C10N 2030/54 20200501;
C10M 2223/045 20130101; C10N 2030/52 20200501; C10M 2215/065
20130101; C10M 169/044 20130101; C10M 2207/028 20130101; C10M
2207/026 20130101; C10N 2030/04 20130101; C10N 2010/12 20130101;
C10M 2215/066 20130101; C10M 2219/046 20130101; C10M 2209/084
20130101; C10M 2201/066 20130101; C10N 2040/25 20130101; C10M
2207/0406 20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101;
C10M 2203/1025 20130101; C10N 2020/02 20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 2016 |
CN |
PCT/CN2016/110333 |
Claims
1. A lubricant composition for an internal combustion engine
comprising a base oil of lubricating viscosity, wherein the base
oil comprises an ether base stock of formula (A): ##STR00071##
where: R.sub.a and R.sub.b are aliphatic hydrocarbyl groups and may
be the same or different; wherein at least one of R.sub.a and
R.sub.b is branched-chain alkyl, alkoxy-substituted-alkyl or
cycloalkyl-substituted-alkyl; the lubricant composition further
comprising: i) at least one molybdenum compound as a lubricant
additive which is present, on a molybdenum element basis, in an
amount of at least 0.06% by weight of the lubricant composition; or
ii) at least one polymethacrylate compound as a lubricant additive
which is present in an amount of from 0.1 to 7.5% by weight of the
lubricant composition.
2. The lubricant composition of claim 1, wherein R.sub.a and
R.sub.b are independently selected from alkyl,
alkoxy-substituted-alkyl or cycloalkyl-substituted-alkyl, provided
that when R.sub.a and R.sub.b are both alkyl at least one of
R.sub.a and R.sub.b is/are branched-chain alkyl.
3. The lubricant composition of claim 1, wherein R.sub.a contains
more carbon atoms than R.sub.b.
4. The lubricant composition of claim 1, wherein R.sub.a contains
from 12 to 30 carbon atoms, and/or R.sub.b contains from 2 to 20
carbon atoms.
5. The lubricant composition of claim 1, wherein the ether base
stock is of formula (1): ##STR00072## where: R.sub.1 and R.sub.2
are alkyl or, together with the carbon atom to which they are
attached, cycloalkyl; R.sub.3, R.sub.4 and R.sub.5 are H or alkyl;
R.sub.6 is alkyl or ##STR00073## where: R.sub.7 and R.sub.8 are H,
alkyl or, together with the carbon atom to which they are attached,
cycloalkyl; R.sub.9 is H or alkyl; X is alkylene or is absent; and
p is 0, 1, 2 or 3; and m and n are 0, 1, 2 or 3, wherein m is 0
when R.sub.4 and R.sub.5 are H.
6. The lubricant composition of claim 5, wherein R.sub.1 and
R.sub.2 are C.sub.1-15 alkyl or, together with the carbon atom to
which they are attached, C.sub.5-30 cycloalkyl; and/or wherein
R.sub.3, R.sub.4 and R.sub.5 are H or C.sub.1-15 alkyl.
7. The lubricant composition of claim 5, wherein m and n are 0, 1
or 2.
8. The lubricant composition of claim 5, wherein the ether base
stock has the formula (4): ##STR00074## where: R.sub.1 and R.sub.4
are alkyl; R.sub.3 and R.sub.5 are H or alkyl.
9. The lubricant composition of claim 5, wherein the ether base
stock has the formula (7): ##STR00075## where: R.sub.1 and R.sub.2
are alkyl or, together with the carbon to which they are attached,
cycloalkyl; R.sub.3, R.sub.4 and R.sub.5 are H or alkyl; and
R.sub.6 is alkyl.
10. The lubricant composition of claim 1, wherein the ether base
stock contains a total number of carbons atoms of from 20 to
50.
11. The lubricant composition of claim 1, wherein the ether base
stock is prepared from bio-derived feedstock containing greater
than 50% by weight of biobased carbon.
12. The lubricant composition of claim 1, wherein the at least one
molybdenum compound is present, on a molybdenum element basis, in
an amount from 0.06% to 0.25% by weight of the lubricant
composition.
13. The lubricant composition of claim 1, wherein the at least one
polymethacrylate compound is present in an amount of from 0.25 to
7% by weight of the lubricant composition.
14. The lubricant composition of claim 1, wherein the at least one
polymethacrylate compound is a comb-type polymer.
15. The lubricant composition of claim 1, wherein the base oil of
the lubricant composition comprises greater than 10% by weight of
the ether base stock and/or wherein the lubricant composition
comprises greater than 50% by weight of the base oil.
16. The lubricant composition of claim 15, wherein the base oil of
the lubricant composition further comprises a base stock selected
from Group I, Group II, Group III, Group IV and Group V base stocks
and mixtures thereof.
17. The lubricant composition of claim 1, wherein the lubricant
composition has at least one of: a kinematic viscosity at
40.degree. C. of less than 60 cSt; a kinematic viscosity at
100.degree. C. of less than 12 cSt; a viscosity index of greater
than 100; a viscosity at 150.degree. C. and a shear rate of
10.sup.6 s.sup.-1 of no greater than 3 cP; and a Noack volatility
of less than 25% by weight.
18. The lubricant composition of claim 1, wherein the lubricant
composition has at least one of: an oxidative stability performance
on a CEC-L-088-02 test indicated by an absolute viscosity increase
at 40.degree. C. of no more than 45 cSt; an oxidative stability
performance on a CEC-L-109-14 test indicated by an increase in
kinematic viscosity at 100.degree. C. of less than 200%; a fuel
economy performance on a CEC-L-054-96 test of at least 2.5%; a
piston cleanliness performance on a CEC-L-088-02 test indicated by
an overall piston merit of at least 8.5; and a high temperature
stability performance on a KHT test at 280.degree. C. in accordance
with JPI-5S-55-99 indicated by an overall deposit merit of at least
7.0.
19. The lubricant composition of claim 1, wherein the composition
further comprises a phenate detergent in an amount of 0.1 to 5% by
weight actives of the lubricant composition.
20. The lubricant composition of claim 1, wherein the composition
further comprises a neutral sulphonate detergent in an amount of
0.01 to 5% by weight of the lubricant composition.
21. A method of preparing a lubricant composition, said method
comprising providing a base oil as defined in claim 1 and blending
the base oil with: i) at least one molybdenum compound suitable for
use as a lubricant additive such that the molybdenum compound is
present, on a molybdenum element basis, in an amount of at least
0.06% by weight of the lubricant composition; or ii) at least one
polymethacrylate compound suitable for use as a lubricant additive
such that the polymethacrylate compound is present in an amount of
from 0.1 to 7.5% by weight of the lubricant composition, and
optionally also blending one or more additional lubricant
additives, in order to prepare the lubricant composition.
22. A method of lubricating a surface, said method comprising
supplying a lubricant composition as defined in claim 1 to said
surface, such as wherein the lubricant composition is supplied to a
surface in an internal combustion engine.
23-26. (canceled)
27. A method of reducing or preventing i) scuffing in the piston
system of an engine and/or ii) deposits in the turbochargers of an
engine, comprising the step of providing to the engine a lubricant
composition according to claim 1.
28. A method of improving the fuel economy performance and/or
piston cleanliness performance and/or turbocharger cleanliness
performance of an engine and/or a vehicle, comprising the step of
providing to the engine a lubricant composition according to claim
1.
Description
[0001] The present invention relates to lubricant compositions
containing base oils comprising certain ether base stocks which are
suitable for use in a lubricant composition intended for use in an
internal combustion engine. Also provided are methods and uses of
the lubricant compositions and of the ether base stocks.
BACKGROUND
[0002] Lubricating compositions generally comprise a base oil of
lubricating viscosity together with one or more additives to
deliver properties including for example, reduced friction and
wear, improved viscosity index, improved dispersancy, detergency,
and resistance to oxidation and corrosion. A lubricant base oil may
comprise one or more lubricating base stocks.
[0003] Lubricant base stocks used in automotive engine lubricants
are generally obtained from petrochemical sources, for example they
may be obtained as the higher boiling fractions isolated during the
refining of crude oil or as the products of chemical reactions of
feedstocks from petrochemical sources. Lubricant base stocks can
also be made from Fischer-Tropsch wax.
[0004] Lubricant base stocks may be classified as Group I, II, III,
IV and V base stocks according to API standard 1509, "ENGINE OIL
LICENSING AND CERTIFICATION SYSTEM", 17.sup.th Edition, Annex E
(October 2013 with Errata March 2015), as set out in Table 1.
TABLE-US-00001 TABLE 1 Saturated Sulphur content hydrocarbon
content (% by weight) (% by weight) ASTM D2622, D4294, Viscosity
Index Group ASTM D2007 D4927, D3120 or D1552 ASTM D2270 I <90
and/or >0.03 and .gtoreq.80 and <120 II .gtoreq.90 and
.ltoreq.0.03 and .gtoreq.80 and <120 III .gtoreq.90 and
.ltoreq.0.03 and .gtoreq.120 IV Polyalphaolefins V all base stocks
not in Groups I, II, III or IV
[0005] Group I base stocks are typically manufactured by known
processes including, for example, solvent extraction and solvent
dewaxing, or solvent extraction and catalytic dewaxing. Group II
and Group III base stocks are typically manufactured by known
processes including, for example, catalytic hydrogenation and/or
catalytic hydrocracking, and catalytic hydroisomerisation. Group IV
base stocks include for example, hydrogenated oligomers of alpha
olefins.
[0006] A combination of properties is desirable in a base stock for
conferring to a lubricant composition comprising it. In some
instances, for example in passenger car engine oils, it may be
desirable for a base stock to confer a low viscosity profile on the
lubricant composition, since this leads to improved fuel economy,
for instance, as a result of a thinner oil film. In particular, it
is desirable for base stocks to have a low kinematic viscosity as
well as good low-temperature viscosity characteristics, for example
a low pour point or low viscosity as measured using a mini-rotary
viscometer (MRV). However, the general trend is for an improvement
in the viscosity profile (i.e. a reduction in viscosity parameters)
of a base oil to be accompanied by an undesirable increase in
volatility. A lower viscosity can also give rise to excess wear
resulting in shorter engine life as a result of a thinner oil film
for lubricating surfaces of the engine.
[0007] To meet new tougher fuel economy regulations, there has been
a move toward building smaller engines equipped with turbochargers.
However, it is known that turbochargers, which operate at high
temperatures, promote coking related deposit formation which can,
amongst other things, lead to scuffing related engine failure.
Thus, it is also desirable for lubricant compositions to exhibit
good high temperature stability performance so as to reduce high
temperature induced deposit formation.
[0008] Accordingly, there is a need for a lubricant composition
having low volatility for a given viscosity profile, but which is
also suitable for use in an internal combustion engine. There is
also a need for a lubricant composition which offers good fuel
economy performance together with high temperature stability.
SUMMARY
[0009] Accordingly, in a first aspect the present invention
provides a lubricant composition for an internal combustion engine
comprising a base oil of lubricating viscosity, wherein the base
oil comprises an ether base stock of formula (A):
##STR00002##
[0010] where: R.sub.a and R.sub.b are aliphatic hydrocarbyl groups
and may be the same or different; wherein at least one of R.sub.a
and R.sub.b is branched-chain alkyl, alkoxy-substituted-alkyl or
cycloalkyl-substituted-alkyl; [0011] the lubricant composition
further comprising: [0012] i) at least one molybdenum compound as a
lubricant additive which is present, on a molybdenum element basis,
in an amount of at least 0.06% by weight of the lubricant
composition; or [0013] ii) at least one polymethacrylate compound
as a lubricant additive which is present in an amount of from 0.1
to 7.5% by weight of the lubricant composition.
[0014] In a particularly preferred embodiment, the ether base stock
of the lubricant composition is selected from a subset of the
compounds of formula (A), namely a compound of formula (1):
##STR00003##
[0015] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon atom to which they are attached, cycloalkyl; [0016] R.sub.3,
R.sub.4 and R.sub.5 are H or alkyl; [0017] R.sub.6 is alkyl or
##STR00004##
[0018] where: R.sub.7 and R.sub.8 are H, alkyl or, together with
the carbon atom to which they are attached, cycloalkyl; [0019]
R.sub.9 is H or alkyl; [0020] X is alkylene or is absent; and
[0021] p is 0, 1, 2 or 3; and
[0022] m and n are 0, 1, 2 or 3 provided that m is 0 when R.sub.4
and R.sub.5 are H.
[0023] Also provided are methods of preparing lubricant
compositions.
[0024] Also provided is a method for lubricating a surface using a
lubricant composition, as well as the use of a lubricant
composition for lubricating a surface.
[0025] Also provided are methods and uses of improving the high
temperature stability of a lubricant composition, reducing or
preventing turbocharger deposits or piston scuffing in an engine as
well as improving the fuel economy performance and/or turbocharger
cleanliness performance of an engine and/or a vehicle, such as an
automotive vehicle associated with an internal combustion
engine.
DETAILED DESCRIPTION
[0026] A lubricant composition for an internal combustion engine is
provided comprising a base oil of lubricating viscosity, wherein
the base oil comprises an ether base stock of formula (A):
##STR00005##
[0027] where: R.sub.a and R.sub.b are aliphatic hydrocarbyl groups
and may be the same or different; wherein at least one of R.sub.a
and R.sub.b is branched-chain alkyl, alkoxy-substituted-alkyl or
cycloalkyl-substituted-alkyl; [0028] the lubricant composition
further comprising: [0029] i) at least one molybdenum compound as a
lubricant additive which is present, on a molybdenum element basis,
in an amount of at least 0.06% by weight of the lubricant
composition; or [0030] ii) at least one polymethacrylate compound
as a lubricant additive which is present in an amount of from 0.1
to 7.5% by weight of the lubricant composition.
[0031] For the purposes of the present invention, the following
terms as used herein shall, unless otherwise indicated, be
understood to have the following meanings.
[0032] The term "aliphatic hydrocarbyl" as used herein refers to a
group comprising hydrogen and carbon atoms, where one or more
carbon atoms may optionally be replaced with --O--, which group may
be saturated or unsaturated, preferably saturated, and contains
from 1 to 40 carbon atoms. Examples of hydrocarbyl groups include
hydrocarbyl groups containing from 2 to 28 carbon atoms, such as
from 3 to 26 carbon atoms or from 4 to 24 carbon atoms. Where one
or more of the carbon atoms is replaced with --O--, from 2% to 35%
of the carbon atoms are preferably replaced with --O--, or from 5%
to 25%. In other examples, the aliphatic hydrocarbyl group has 1 to
3 carbon atoms replaced with --O--, for example 2 carbon atoms
replaced with --O--. In other examples, none of the carbon atoms
are replaced with --O--.
[0033] Examples of aliphatic hydrocarbyl groups include acyclic
groups, non-aromatic cyclic groups and groups comprising both an
acyclic portion and a non-aromatic cyclic portion. The aliphatic
hydrocarbyl group may be straight chain or branched chain. The
aliphatic hydrocarbyl group includes monovalent groups and
polyvalent groups as specified. Examples of monovalent hydrocarbyl
groups include alkyl, alkenyl, alkynyl and carbocyclyl (e.g.
cycloalkyl or cycloalkenyl).
[0034] The term "alkyl" as used herein refers to a monovalent
straight or branched chain alkyl moiety containing from 1 to 40
carbon atoms. Examples of alkyl groups include alkyl groups
containing from 1 to 30 carbon atoms, e.g. from 2, 3 or 4 carbon
atoms to 24, 25, or 26 carbon atoms, e.g. from 1 to 20 carbon
atoms, from 1 to 14 carbon atoms, from 2 to 26 carbon atoms and
from 3 to 24 carbon atoms. Particular examples include alkyl groups
containing 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 and 30 carbon
atoms. Examples of alkyl groups include methyl, ethyl, n-propyl,
isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl and the
like. Unless specifically indicated otherwise, the term "alkyl"
does not include optional substituents.
[0035] The term "cycloalkyl" as used herein refers to a monovalent
saturated aliphatic hydrocarbyl moiety containing from 3 to 40
carbon atoms and containing at least one ring, wherein said ring
has at least 3 ring carbon atoms. The cycloalkyl groups mentioned
herein may optionally have alkyl groups attached thereto. Examples
of cycloalkyl groups include cycloalkyl groups containing from 3 to
16 carbon atoms, e.g. from 3 to 10 carbon atoms. Particular
examples include cycloalkyl groups containing 3, 4, 5 or 6 ring
carbon atoms. Examples of cycloalkyl groups include groups that are
monocyclic, polycyclic (e.g. bicyclic) or bridged ring system.
Examples of cycloalkyl groups include cyclopropyl, cyclobutyl,
cyclopentyl, cyclohexyl and the like.
[0036] The term "alkenyl" as used herein refers to a monovalent
straight or branched chain alkyl group containing from 2 to 40
carbon atoms and containing, in addition, at least one
carbon-carbon double bond, of either E or Z configuration unless
specified. Examples of alkenyl groups include alkenyl groups
containing from 2 to 28 carbon atoms, e.g. from 3 to 26 carbon
atoms, e.g. from 4 to 24 carbon atoms. Particular examples include
alkenyl groups containing 2, 3, 4, 5 or 6 carbon atoms. Examples of
alkenyl groups include ethenyl, 2-propenyl, 1-butenyl, 2-butenyl,
3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 1-hexenyl,
2-hexenyl, 3-hexenyl and the like.
[0037] The term "alkylene" refers to a divalent straight or
branched chain saturated hydrocarbyl group consisting of hydrogen
and carbon atoms and containing from 1 to 30 carbon atoms. Examples
of alkylene groups include alkylene groups that contain from 1 to
20 carbon atoms, e.g. from 1 to 12 carbon atoms, e.g. from 1 to 10
carbon atoms. Particular examples include alkylene groups that
contain 1, 2, 3, 4, 5 or 6 carbon atoms.
[0038] The term "alkoxy" as used herein refers to --O-alkyl,
wherein alkyl is as defined herein. In some examples an alkoxy
group contains from 1 to 40 carbon atoms, e.g. from 1 to 28 carbon
atoms, or from 1 to 26 carbon atoms, or from 1 to 24 carbon atoms
e.g. from 1 to 10 carbon atoms. Particular examples include alkoxy
groups that contain 1, 2, 3, 4, 5 or 6 carbon atoms. Examples of
alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy,
tert-butoxy, pentoxy, hexoxy and the like.
[0039] The terms "alkoxy-substituted-alkyl" and
"cycloalkyl-substituted-alkyl" refer to a straight or branched
chain alkyl group in which one of the hydrogens of the alkyl chain
is replaced with an alkoxy or cycloalkyl group as described herein,
respectively.
[0040] In some embodiments, R.sub.a and R.sub.b of formula (A) are
independently selected from alkyl, alkoxy-substituted-alkyl and
cycloalkyl-substituted-alkyl, provided that where R.sub.a and
R.sub.b are both alkyl at least one of R.sub.a and R.sub.b is
branched-chain alkyl. In preferred embodiments, when R.sub.a and
R.sub.b are both alkyl, both R.sub.a and R.sub.b are branched-chain
alkyl.
[0041] In some embodiments, R.sub.a and R.sub.b of formula (A) are
independently selected from C.sub.1-30 alkyl, such as C.sub.2-20
alkyl, C.sub.5-30 cycloalkyl-substituted-alkyl, such as C.sub.5-25
cycloalkyl-substituted-alkyl, or C.sub.2-30
alkoxy-substituted-alkyl, such as C.sub.2-20
alkoxy-substituted-alkyl.
[0042] In some embodiments, R.sub.a of formula (A) contains more
carbon atoms than R.sub.b.
[0043] In some embodiments, R.sub.a of formula (A) contains from 12
to 30 carbon atoms, preferably from 12 to 26 carbon atoms, and/or
R.sub.b contains from 2 to 20 carbon atoms, preferably from 2 to 12
carbon atoms.
[0044] In particularly preferred embodiments, the ether base stock
of the lubricant composition is a compound of formula (1):
##STR00006##
[0045] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon atom to which they are attached, cycloalkyl;
[0046] R.sub.3, R.sub.4 and R.sub.5 are H or alkyl;
[0047] R.sub.6 is alkyl or
##STR00007##
[0048] where: R.sub.7 and R.sub.8 are H, alkyl or, together with
the carbon atom to which they are attached, cycloalkyl; [0049]
R.sub.9 is H or alkyl; [0050] X is alkylene or is absent; and
[0051] p is 0, 1, 2 or 3; and
[0052] m and n are 0, 1, 2 or 3 provided that m is 0 when R.sub.4
and R.sub.5 are H.
[0053] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as C.sub.2-12 alkyl or, together with
the carbon atom to which they are attached, C.sub.5-25
cycloalkyl.
[0054] In some embodiments, R.sub.3, R.sub.4 and R.sub.5 are H or
C.sub.1-15 alkyl, such as H or C.sub.2-12 alkyl. Preferably,
R.sub.5 is H.
[0055] In some embodiments, R.sub.6 is C.sub.1-20 alkyl or
##STR00008##
such as C.sub.1-16 alkyl or
##STR00009##
[0056] In some embodiments, R.sub.7 and R.sub.8 are H, C.sub.1-20
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as H, C.sub.2-12 alkyl or, together
with the carbon atom to which they are attached, C.sub.5-25
cycloalkyl. Preferably, R.sub.7 and R.sub.8 are C.sub.1-20 alkyl,
such as C.sub.2-12 alkyl.
[0057] In some embodiments, R.sub.9 is H or C.sub.1-20 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.9 is H.
[0058] In some embodiments, X is C.sub.1-20 alkylene, such as
C.sub.3-15 alkylene.
[0059] In some embodiments, p is 0, 1 or 2, such as 0 or 1.
[0060] In some embodiments, m and n are 0, 1 or 2, such as 0 or
1.
[0061] R.sub.1 and R.sub.2 are as described as alkyl or, together
with the carbon atom to which they are attached, cycloalkyl. It
will be understood that, where R.sub.1 and R.sub.2 are both alkyl
groups, they may be the same as or different from one another.
Similar considerations apply to other substituents which are
defined as part of a group of substituents. Thus, the
considerations apply, for example, to R.sub.3, R.sub.4 and R.sub.5;
to R.sub.7 and R.sub.8; and to the values taken by m and n. For
instance, where R.sub.3, R.sub.4 and R.sub.5 are described as being
H or alkyl, it will be understood that each of R.sub.3, R.sub.4 and
R.sub.5 may be H, each of R.sub.3, R.sub.4 and R.sub.5 may be
alkyl, or a subset of R.sub.3, R.sub.4 and R.sub.5 may be H and
another subset of R.sub.3, R.sub.4 and R.sub.5 may be alkyl. Where
R.sub.3, R.sub.4 and R.sub.5, or a subset thereof, are alkyl, each
of R.sub.3, R.sub.4 and R.sub.5 may be the same alkyl group or they
may be different alkyl groups. In contrast, where R.sub.1 (or any
other notation) is used at a number of locations in a formula, it
is used to denote the presence of the same group at each of these
locations.
[0062] In each of the embodiments disclosed herein, the ether
compounds of the lubricant compositions may contain a total number
of carbons atoms of from about 20 to about 50. For instance, the
total number of carbons in the ether compounds may be from about 25
to about 45, such as from about 28 to about 40 or from about 28 to
about 36.
[0063] As indicated previously, the alkyl and alkylene groups
mentioned herein, i.e. those that may be represented by R.sub.a,
R.sub.b, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6,
R.sub.7, R.sub.8, R.sub.9 and X, may be straight chain alkyl or
alkylene groups, though they may also be branched. In some
embodiments, each alkyl group and each alkylene group contains a
single branch point or is a straight chain alkyl or alkylene group.
For example, when R.sub.a and R.sub.b are both alkyl groups, at
least one of these alkyl groups is branched, preferably both. In
some embodiments, for instance with respect to R.sub.1, R.sub.2,
R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9 and X
groups, the alkyl and alkylene groups are straight chain alkyl or
alkylene groups. It will be understood that, aside from alkyl
branching (if present), the alkyl and alkylene groups are
unsubstituted unless otherwise indicated and so may not contain any
atoms other than carbon or hydrogen.
[0064] The ether compounds described herein may be used for
improving the high temperature stability of a lubricant
composition, for reducing or preventing scuffing in the piston
system of an engine or for reducing or preventing deposits in the
turbochargers or other hot surfaces, for example piston
undercrowns, of an engine. The presence of a molybdenum compound or
polymethacrylate compound as defined herein, as well as phenate
and/or neutral sulphonate detergents, in the lubricant compositions
of the invention have also been found to enhance high temperature
stability in the ether based lubricant compositions and/or be
better tolerated in terms of high temperature stability in ether
based compositions as defined herein in comparison with
conventional non-ether based lubricant compositions.
[0065] Accordingly, the lubricant compositions of the invention may
also be used for reducing or preventing scuffing in the pistons of
an engine or for reducing or preventing deposits in the
turbochargers or other hot surfaces of an engine. There is also
provided the use of the lubricant compositions of the invention for
improving the fuel economy performance and/or piston cleanliness
performance and/or turbocharger cleanliness performance of an
engine and/or a vehicle, such as an automotive vehicle associated
with an internal combustion engine.
[0066] Accordingly, there is also provided a method of reducing or
preventing i) scuffing in the pistons of an engine and/or ii)
deposits in the turbochargers of an engine, comprising the step of
providing to the engine a lubricant composition as described
herein. There is also provided a method of improving the fuel
economy performance and/or piston cleanliness performance and/or
turbocharger cleanliness performance of an engine and/or a vehicle,
such as an automotive vehicle associated with an internal
combustion engine comprising the step of providing the engine
and/or the vehicle with a lubricant composition as described
herein.
[0067] The compounds of formula (A) and/or formula (1) may have a
kinematic viscosity at 40.degree. C. of less than about 25 cSt,
such as less than about 20 cSt, or less than about 17 cSt.
[0068] The compounds may have a kinematic viscosity at 100.degree.
C. of less than about 7 cSt, such as less than about 5 cSt, or less
than about 4 cSt. The compounds may have a viscosity index of
greater than about 100, such as greater than about 110, or greater
than about 120. The kinematic viscosity at 40.degree. C. and the
kinematic viscosity at 100.degree. C. may be measured according to
ASTM D7279. The viscosity index may be measured according to ASTM
D2270.
[0069] The compounds may have a Noack volatility of less than about
26%, such as less than about 20%, less than about 16%, or less than
about 12% by weight. Noack volatility may be measured according to
CEC-L-40-A-93.
[0070] The compounds may have a viscosity at 150.degree. C. and a
shear rate of 10.sup.6 s.sup.-1 of no greater than 1.7 cP, such as
no greater than 1.5 cP. This high temperature high shear viscosity
may be measured according to CEC-L-36-A-90.
[0071] The ether compounds described herein may have a pour point
of less than -10.degree. C., such as less than about -25.degree.
C., or less than about -35.degree. C. Pour point may be measured
according to ASTM D5950.
[0072] The ether compounds may have a cold-crankcase simulator
viscosity at -35.degree. C. of less than about 1800 cP, such as
less than about 1500 cP, or less than about 1200 cP, for example as
measured according to ASTM D5293.
[0073] The ether compounds may have a DSC oxidation onset
temperature of greater than about 165.degree. C., such as greater
than about 175.degree. C., or greater than about 185.degree. C.,
for example as measured according to ASTM E2009 (method B).
[0074] In particular embodiments, the ether compounds of formula
(A) or formula (1) may have a kinematic viscosity at 100.degree. C.
of about 3 to about 4 cSt and a Noack volatility of less than about
20%, such as less than about 16%, or less than about 12%, by
weight; or a kinematic viscosity at 100.degree. C. of about 2 to
about 3 cSt, and a Noack volatility of less than about 40%, such as
less than about 30%, by weight.
[0075] The ether compounds of formula (A) or formula (1) are
particularly suited for blending into a lubricant composition. In
particular, the compounds are miscible with conventional base
stocks, including hydrocarbon base stocks, as well as with
conventional lubricant additives. Moreover, the compounds may be
used in a lubricant composition in a relatively high amount (for
example, in an amount of greater than about 10% by weight, such as
greater than about 20% by weight or greater than about 30% by
weight) whilst meeting elastomer compatibility requirements for
lubricant compositions.
[0076] The compounds of formula (A) and formula (1) may be prepared
from a wide range of commercially available feedstocks.
[0077] In some embodiments, the compounds are prepared from
bio-derived feedstocks. For instance, the compounds may contain
greater than about 50%, such as greater than about 70%, or greater
than about 80% by weight of biobased carbon. The biobased carbon
content of the compounds may be measured according to ASTM
D6866.
Guerbet-Derived Base Stocks
[0078] In preferred embodiments, the compounds of formula (1) are
derived from .beta.-alkylated alcohols. In these embodiments, the
compound may have the formula (2):
##STR00010##
[0079] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon atom to which they are attached, cycloalkyl; [0080] R.sub.3
and R.sub.5 are H or alkyl; [0081] R.sub.4 is alkyl; [0082] R.sub.6
is alkyl or
##STR00011##
[0083] where: R.sub.7 and R.sub.8 are H, alkyl or, together with
the carbon atom to which they are attached, cycloalkyl; [0084]
R.sub.9 is H or alkyl; [0085] X is alkylene or is absent; and
[0086] p is 0, 1, 2 or 3; and
[0087] n is 0, 1, 2 or 3.
[0088] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as C.sub.2-12 alkyl or, together with
the carbon atom to which they are attached, C.sub.5-25 cycloalkyl.
Preferably, R.sub.1 and R.sub.2 are C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0089] In some embodiments, R.sub.3 and R.sub.5 are H or C.sub.1-15
alkyl, such as H or C.sub.2-12 alkyl. Preferably, R.sub.3 and
R.sub.5 are H.
[0090] In some embodiments, R.sub.4 is C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0091] In some embodiments, R.sub.6 is C.sub.1-15 alkyl or
##STR00012##
such as
[0092] C.sub.1-12 alkyl or
##STR00013##
[0093] In some embodiments, R.sub.7 and R.sub.8 are H, C.sub.1-20
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as H, C.sub.2-12 alkyl or, together
with the carbon atom to which they are attached, C.sub.5-25
cycloalkyl. Preferably, R.sub.7 and R.sub.8 are C.sub.1-20 alkyl,
such as C.sub.2-12 alkyl.
[0094] In some embodiments, R.sub.9 is H or C.sub.1-20 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.9 is H.
[0095] In some embodiments, X is C.sub.1-20 alkylene, such as
C.sub.3-15 alkylene.
[0096] In some embodiments, p is 0, 1 or 2, such as 0 or 1.
[0097] In some embodiments, n is 0, 1 or 2, such as 0 or 1.
[0098] Where the compound is derived from a .beta.-alkylated
alcohol, it is preferably derived, at least in part, from a Guerbet
alcohol. Compounds which are derived, at least in part, from
Guerbet alcohols may have the formula (3):
##STR00014##
[0099] where: R.sub.1 is alkyl;
[0100] R.sub.3 and R.sub.5 are H or alkyl;
[0101] R.sub.4 is alkyl;
[0102] R.sub.6 is alkyl or
##STR00015##
[0103] where: R.sub.7 and R.sub.8 are H, alkyl or, together with
the carbon atom to which they are attached, cycloalkyl; [0104]
R.sub.9 is H or alkyl; [0105] X is alkylene or is absent; and
[0106] p is 0, 1, 2 or 3; and
[0107] n is 0, 1, 2 or 3.
[0108] In some embodiments, R.sub.1 is C.sub.1-12 alkyl, such as
C.sub.2-10 alkyl.
[0109] In some embodiments, R.sub.3 is H or C.sub.1-12 alkyl, such
as H or C.sub.2-10 alkyl. Preferably, R.sub.3 is H.
[0110] In some embodiments, R.sub.4 is C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0111] In some embodiments, R.sub.5 is H or C.sub.1-15 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.5 is H.
[0112] In some embodiments, R.sub.6 is C.sub.1-15 alkyl or
##STR00016##
such as C.sub.1-12 alkyl or
##STR00017##
Preferably, R.sub.6 is C.sub.1-15 alkyl, such as C.sub.1-12
alkyl.
[0113] In some embodiments, R.sub.7 and R.sub.8 are H, C.sub.1-20
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as H, C.sub.2-12 alkyl or, together
with the carbon atom to which they are attached, C.sub.5-25
cycloalkyl. Preferably, R.sub.7 and R.sub.8 are C.sub.1-20 alkyl,
such as C.sub.2-12 alkyl.
[0114] In some embodiments, R.sub.9 is H or C.sub.1-20 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.9 is H.
[0115] In some embodiments, X is C.sub.1-20 alkylene, such as
C.sub.3-15 alkylene.
[0116] In some embodiments, p is 0, 1 or 2, such as 0 or 1.
[0117] In some embodiments, n is 0, 1 or 2, such as 0 or 1.
[0118] One portion of the compound of formula (3) has a structure
which may be derived from a Guerbet alcohol (i.e. the portion
containing R.sub.1 and R.sub.3), whereas the other portion need not
be derived from a Guerbet alcohol (i.e. the portion containing
R.sub.4, R.sub.5 and R.sub.6). However, in preferred embodiments,
the compound may be derived from a combination of two Guerbet
alcohols. A compound prepared in this way may have the formula
(4):
##STR00018##
[0119] where: R.sub.1 and R.sub.4 are alkyl; [0120] R.sub.3 and
R.sub.5 are H or alkyl.
[0121] In some embodiments, R.sub.1 and R.sub.4 are C.sub.1-12
alkyl, such as C.sub.2-10 alkyl.
[0122] In some embodiments, R.sub.3 and R.sub.5 are H or C.sub.1-12
alkyl, such as H or C.sub.2-10 alkyl. Preferably, R.sub.3 and
R.sub.5 are H.
[0123] In particular embodiments: R.sub.1 is C.sub.4-12 alkyl, such
as C.sub.6-10 alkyl; [0124] R.sub.3 is H; [0125] R.sub.4 is
C.sub.1-10 alkyl, such as C.sub.2-8 alkyl; and [0126] R.sub.5 is
H.
[0127] Two different Guerbet alcohols may be combined to form
compounds of formula (4), in which case R.sub.1 and R.sub.4 may be
different. Alternatively, R.sub.3 and R.sub.5 may be different. In
some embodiments, R.sub.1 and R.sub.4 are different and R.sub.3 and
R.sub.5 are also different.
[0128] However, in some embodiments, the compound may be derived
from a reaction in which the same Guerbet alcohols are combined. A
compound prepared in this way may have the formula (5):
##STR00019##
[0129] where: R.sub.1 is alkyl; and [0130] R.sub.3 is H or
alkyl.
[0131] In some embodiments, R.sub.1 is C.sub.1-10 alkyl, such as
C.sub.2-9 alkyl.
[0132] In some embodiments, R.sub.3 is H or C.sub.1-0 alkyl, such
as H or C.sub.2-8 alkyl. Preferably, R.sub.3 is H.
[0133] In particular embodiments: R.sub.1 is C.sub.3-10 alkyl, such
as C.sub.4-8 alkyl; and R.sub.3 is H.
[0134] Compounds that are derived from Guerbet alcohols include
compounds GE1-GE3, GES, GE7-GE9, SE1, SE2 and TE1 as shown in Table
2.
[0135] Guerbet alcohols may be prepared, for example, by dimerising
primary alcohols to form a .beta.-alkylated alcohol product in a
Guerbet reaction:
##STR00020##
[0136] where R.sub.1 and R.sub.3 are as defined previously;
[0137] and/or:
##STR00021##
[0138] where R.sub.4 and R.sub.5 are as defined previously.
[0139] Guerbet reactions are well-known to the skilled person. The
reactions are typically carried out at elevated temperatures in the
presence of a catalyst.
[0140] The compound may be prepared from the Guerbet alcohol, for
example, according to the following reaction:
##STR00022##
[0141] where: Y is a leaving group; and
[0142] R.sub.1, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and n are as
defined previously for the compound of formula (3).
[0143] Where two Guerbet alcohols are combined to form a compound,
one of the Guerbet alcohols may first be modified so that it
contains a leaving group, Y, and the compound then prepared:
##STR00023##
then:
##STR00024##
or
##STR00025##
then:
##STR00026##
[0144] where: Y is a leaving group; and
[0145] R.sub.1, R.sub.3, R.sub.4 and R.sub.5 are as defined
previously for the compound of formula (4).
[0146] Where the same Guerbet alcohols are combined to form a
compound, they may be combined, for example, according to the
following reactions:
##STR00027##
then:
##STR00028##
[0147] where: Y is a leaving group; and [0148] R.sub.1 and R.sub.3
are as defined previously for the compound of formula (5).
[0149] Methods and reaction conditions for modifying a Guerbet
alcohol so that it contains a leaving group, Y, are known to the
skilled person. For instance, a mesylate group may be introduced by
reacting the Guerbet alcohol with mesyl chloride in the presence of
triethylamine. A bromide group may be introduced by reacting the
Guerbet alcohol with N-bromosuccinimide and triphenyl
phosphine.
[0150] Methods and reaction conditions for carrying out
etherification reactions are known to the skilled person. A base
(for example potassium hydroxide or potassium tert-butoxide), a
catalyst (for example Starks' catalyst:
N-Methyl-N,N,N-trioctyloctan-1-ammonium chloride) or both may be
used in the abovementioned compound forming reactions, i.e. the
etherification reactions.
[0151] In the abovementioned compound forming reactions, Y may be
any suitable leaving group, such as a halogen (for example bromine,
chlorine or iodine) or a sulfonate ester (for example mesylate or
tosylate).
Secondary and Tertiary Ether Base Stocks
[0152] In some preferred embodiments, the compounds of formula (1)
are secondary or tertiary ether compounds. In these embodiments,
the compound may have the formula (6):
##STR00029##
[0153] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon to which they are attached, cycloalkyl; [0154] R.sub.3,
R.sub.4 and R.sub.5 are H or alkyl;
[0155] R.sub.6 is alkyl or
##STR00030##
[0156] where: R.sub.7 and R.sub.8 are H, alkyl or, together with
the carbon atom to which they are attached, cycloalkyl; [0157]
R.sub.9 is H or alkyl; [0158] X is alkylene or is absent; and
[0159] p is 0, 1, 2 or 3; and
[0160] n is 0, 1, 2 or 3.
[0161] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as C.sub.2-12 alkyl or, together with
the carbon atom to which they are attached, C.sub.5-25 cycloalkyl.
Preferably, R.sub.1 and R.sub.2 are C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0162] In some embodiments, R.sub.3, R.sub.4 and R.sub.5 are H or
C.sub.1-15 alkyl, such as H or C.sub.2-12 alkyl. Preferably,
R.sub.5 is H.
[0163] In some embodiments, R.sub.6 is C.sub.1-20 alkyl or
##STR00031##
such as C.sub.1-16 alkyl or
##STR00032##
[0164] In some embodiments, R.sub.7 and R.sub.8 are H, C.sub.1-20
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as H, C.sub.2-12 alkyl or, together
with the carbon atom to which they are attached, C.sub.5-25
cycloalkyl. Preferably, R.sub.7 and R.sub.8 are C.sub.1-20 alkyl,
such as C.sub.2-12 alkyl.
[0165] In some embodiments, R.sub.9 is H or C.sub.1-20 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.9 is H.
[0166] In some embodiments, X is C.sub.1-20 alkylene, such as
C.sub.3-15 alkylene.
[0167] In some embodiments, p is 0, 1 or 2, such as 0 or 1.
[0168] In some embodiments, n is 0, 1 or 2, such as 0 or 1.
[0169] Secondary and tertiary ether compounds may have the formula
(7):
##STR00033##
[0170] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon to which they are attached, cycloalkyl; [0171] R.sub.3,
R.sub.4 and R.sub.5 are H or alkyl; and [0172] R.sub.6 is
alkyl.
[0173] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl or, together with the carbon to which they are attached,
C.sub.5-30 cycloalkyl, such as C.sub.2-12 alkyl or, together with
the carbon to which they are attached, C.sub.5-25 cycloalkyl.
[0174] In some embodiments, R.sub.3, R.sub.4 and R.sub.5 are H or
C.sub.1-15 alkyl, such as H or C.sub.2-12 alkyl. Preferably,
R.sub.5 is H.
[0175] In some embodiments, R.sub.6 is C.sub.1-20 alkyl, such as
C.sub.1-16 alkyl.
[0176] The compounds may be secondary ether compounds of formula
(8):
##STR00034##
[0177] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon to which they are attached, cycloalkyl; [0178] R.sub.4 and
R.sub.5 are H or alkyl; and [0179] R.sub.6 is alkyl.
[0180] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl, such as C.sub.2-12 alkyl.
[0181] In other embodiments, the secondary ether may be obtained
from a cyclic compound. In this case, R.sub.1 and R.sub.2, together
with the carbon to which they are attached, form a cycloalkyl
group, such as a C.sub.5-30 cycloalkyl or a C.sub.5-25 cycloalkyl.
The cycloalkyl group may contain a cyclopentyl, cyclohexyl or
cycloheptyl group optionally having one or more alkyl groups, such
as C.sub.1-12 alkyl or C.sub.1-8 alkyl, attached thereto.
[0182] In some embodiments, R.sub.4 and R.sub.5 are H or C.sub.1-15
alkyl, such as H or C.sub.2-12 alkyl. Preferably, R.sub.5 is H.
[0183] In some embodiments, R.sub.6 is C.sub.1-20 alkyl, such as
C.sub.1-16 alkyl.
[0184] In particular embodiments: R.sub.1 and R.sub.2 are
C.sub.3-12 alkyl, such as C.sub.5-10 alkyl; [0185] R.sub.4 and
R.sub.5 are H; and [0186] R.sub.6 is C.sub.4-20 alkyl, such as
C.sub.6-15 alkyl.
[0187] In other particular embodiments: R.sub.1 and R.sub.2 are
C.sub.3-12 alkyl, such as C.sub.5-10 alkyl; [0188] R.sub.4 is
C.sub.3-12 alkyl, such as C.sub.5-10 alkyl; [0189] R.sub.5 is H;
and [0190] R.sub.6 is C.sub.3-12 alkyl, such as C.sub.5-10
alkyl.
[0191] The compounds may be tertiary ether compounds of formula
(9):
##STR00035##
[0192] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon to which they are attached, cycloalkyl; [0193] R.sub.3 is
alkyl; [0194] R.sub.4 and R.sub.5 are H or alkyl; and [0195]
R.sub.6 is alkyl.
[0196] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl or, together with the carbon to which they are attached,
C.sub.5-30 cycloalkyl, such as C.sub.2-12 alkyl or, together with
the carbon to which they are attached, C.sub.5-25 cycloalkyl.
Preferably, R.sub.1 and R.sub.2 are C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0197] In some embodiments, R.sub.3 is C.sub.1-12 alkyl, such as
C.sub.1-10 alkyl.
[0198] In some embodiments, R.sub.4 and R.sub.5 are H or C.sub.1-15
alkyl, such as H or C.sub.2-12 alkyl.
[0199] In some embodiments, R.sub.6 is C.sub.1-20 alkyl, such as
C.sub.1-16 alkyl.
[0200] In particular embodiments: R.sub.1 and R.sub.2 are
C.sub.2-12 alkyl, such as C.sub.4-10 alkyl; [0201] R.sub.3 is
C.sub.1-10 alkyl, such as C.sub.1-8 alkyl; [0202] R.sub.4 and
R.sub.5 are H; and [0203] R.sub.6 is C.sub.4-20 alkyl, such as
C.sub.6-15 alkyl.
[0204] In other particular embodiments: R.sub.1, R.sub.2 and
R.sub.3 are C.sub.2-12 alkyl, such as C.sub.4-10 alkyl; [0205]
R.sub.3 is C.sub.1-10 alkyl, such as C.sub.1-8 alkyl; [0206]
R.sub.4 is C.sub.3-12 alkyl, such as C.sub.5-10 alkyl; [0207]
R.sub.5 is H; and [0208] R.sub.6 is C.sub.3-12 alkyl, such as
C.sub.5-10 alkyl.
[0209] Examples of secondary and tertiary ether compounds include
SE1, SE2 and TE1 as shown in Table 2.
[0210] The secondary and tertiary ether compounds may be prepared
according to the following reactions:
##STR00036##
or:
##STR00037##
[0211] where: Y is a leaving group; and [0212] R.sub.1, R.sub.2,
R.sub.3, R.sub.4, R.sub.5, R.sub.6 and n are as defined previously
for the compound of formula (6).
[0213] Similarly:
##STR00038##
or:
##STR00039##
[0214] where: Y is a leaving group; and [0215] R.sub.1, R.sub.2,
R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are as defined previously for
the compound of formula (7).
[0216] The skilled person will be aware of methods and reaction
conditions for carrying out these etherification reactions. For
instance, the reaction may be carried out in the presence of
magnesium sulfate, sulfuric acid and dichloromethane.
[0217] Secondary and tertiary alcohol starting materials for use in
etherification reactions will generally be commercially available,
or they may be obtained from commercially available ketones.
[0218] The groups
##STR00040##
may be prepared by introducing a leaving group, Y, into the alcohol
starting materials. Methods and reaction conditions for introducing
the leaving group into alcohol are known to the skilled person.
[0219] In the abovementioned secondary and tertiary ether compound
forming reactions, Y may be any suitable leaving group, such as a
halogen (for example bromine, chlorine or iodine) or a sulfonate
ester (for example mesylate or tosylate).
Secondary or Tertiary Ethers Derived from a Guerbet Alcohol
[0220] In some embodiments, the compound may comprise an ether
which is derived on one side from a secondary or tertiary alcohol
and is derived on the other side from a Guerbet alcohol. In these
embodiments, the compound may have the formula (10):
##STR00041##
[0221] where: R.sub.1 and R.sub.4 are alkyl; [0222] R.sub.3 and
R.sub.5 are H or alkyl;
[0223] R.sub.6 is alkyl or
##STR00042##
[0224] where: R.sub.7 and R.sub.8 are H, alkyl or, together with
the carbon atom to which they are attached, cycloalkyl; [0225]
R.sub.9 is H or alkyl; [0226] X is alkylene or is absent; and
[0227] and p is 0, 1, 2 or 3.
[0228] In some embodiments, R.sub.1 is C.sub.1-12 alkyl, such as
C.sub.2-10 alkyl.
[0229] In some embodiments, R.sub.3 is H or C.sub.1-12 alkyl, such
as H or C.sub.2-10 alkyl. Preferably, R.sub.3 is H.
[0230] In some embodiments, R.sub.4 is C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0231] In some embodiments, R.sub.5 is H or C.sub.1-15 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.5 is H.
[0232] In some embodiments, R.sub.6 is C.sub.1-15 alkyl or
##STR00043##
such as C.sub.1-12 alkyl or
##STR00044##
[0233] In some embodiments, R.sub.7 and R.sub.8 are H, C.sub.1-20
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as H, C.sub.2-12 alkyl or, together
with the carbon atom to which they are attached, C.sub.5-25
cycloalkyl. Preferably, R.sub.7 and R.sub.8 are C.sub.1-20 alkyl,
such as C.sub.2-12 alkyl.
[0234] In some embodiments, R.sub.9 is H or C.sub.1-20 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.9 is H.
[0235] In some embodiments, X is C.sub.1-20 alkylene, such as
C.sub.3-15 alkylene.
[0236] In some embodiments, p is 0, 1 or 2, such as 0 or 1.
[0237] Examples of secondary and tertiary ether compounds derived
from a Guerbet-alcohol include compounds SE1, SE2 and TE1 as shown
in Table 2.
Di-Ether Base Stocks
[0238] It is generally preferred that the compounds of formula (1)
are monoethers. However, in some embodiments, the compound is a
diether compound. Such compounds may have the formula (11):
##STR00045##
[0239] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon atom to which they are attached, cycloalkyl; [0240] R.sub.3,
R.sub.4 and R.sub.5 are H or alkyl; [0241] R.sub.7 and R.sub.8 are
H, alkyl or, together with the carbon atom to which they are
attached, cycloalkyl; [0242] R.sub.9 is H or alkyl; [0243] X is
alkylene or is absent; [0244] p is 0, 1, 2 or 3; and [0245] m and n
are 0, 1, 2 or 3.
[0246] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl or, together with the carbon to which they are attached,
C.sub.5-30 cycloalkyl, such as C.sub.2-12 alkyl or, together with
the carbon to which they are attached, C.sub.5-25 cycloalkyl.
Preferably, R.sub.1 and R.sub.2 are C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0247] In some embodiments, R.sub.3, R.sub.4 and R.sub.5 are H or
C.sub.1-15 alkyl, such as H or C.sub.2-12 alkyl. Preferably,
R.sub.3 and R.sub.5 are H.
[0248] In some embodiments, R.sub.7 and R.sub.8 are H, C.sub.1-20
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as H, C.sub.2-12 alkyl or, together
with the carbon atom to which they are attached, C.sub.5-25
cycloalkyl. Preferably, R.sub.7 and R.sub.8 are C.sub.1-20 alkyl,
such as C.sub.2-12 alkyl.
[0249] In some embodiments, R.sub.9 is H or C.sub.1-20 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.9 is H.
[0250] In some embodiments, X is C.sub.1-20 alkylene, such as
C.sub.3-15 alkylene.
[0251] In some embodiments, p is 0, 1 or 2, such as 0 or 1.
[0252] In some embodiments, m and n are 0, 1 or 2, such as 0 or
1.
[0253] In some embodiments, the diether compound may contain two
ether groups, at least one of which is derived from a
.beta.-alkylated alcohol. In such embodiments, the compound may
have the formula (12):
##STR00046##
[0254] where: R.sub.1 and R.sub.2 are alkyl or, together with the
carbon atom to which they are attached, cycloalkyl; [0255] R.sub.3,
R.sub.4 and R.sub.5 are H or alkyl; [0256] R.sub.7 and R.sub.8 are
H, alkyl or, together with the carbon atom to which they are
attached, cycloalkyl; [0257] R.sub.9 is H or alkyl; [0258] X is
alkylene or is absent; [0259] p is 0, 1, 2 or 3; and [0260] n is 0,
1, 2 or 3.
[0261] In some embodiments, R.sub.1 and R.sub.2 are C.sub.1-15
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as C.sub.2-12 alkyl or, together with
the carbon atom to which they are attached, C.sub.5-25 cycloalkyl.
Preferably, R.sub.1 and R.sub.2 are C.sub.1-15 alkyl, such as
C.sub.2-12 alkyl.
[0262] In some embodiments, R.sub.3, R.sub.4 and R.sub.5 are H or
C.sub.1-15 alkyl, such as H or C.sub.2-12 alkyl. Preferably,
R.sub.3 and R.sub.5 are H. Preferably, R.sub.4 is C.sub.1-15 alkyl,
such as C.sub.2-12 alkyl
[0263] In some embodiments, R.sub.7 and R.sub.8 are H, C.sub.1-20
alkyl or, together with the carbon atom to which they are attached,
C.sub.5-30 cycloalkyl, such as H, C.sub.2-12 alkyl or, together
with the carbon atom to which they are attached, C.sub.5-25
cycloalkyl. Preferably, R.sub.7 and R.sub.8 are C.sub.1-20 alkyl,
such as C.sub.2-12 alkyl.
[0264] In some embodiments, R.sub.9 is H or C.sub.1-20 alkyl, such
as H or C.sub.2-12 alkyl. Preferably, R.sub.9 is H.
[0265] In some embodiments, X is C.sub.1-20 alkylene, such as
C.sub.3-15 alkylene.
[0266] In some embodiments, p is 0, 1 or 2, such as 0 or 1.
[0267] In some embodiments, n is 0, 1 or 2, such as 0 or 1.
[0268] Examples of Guerbet-derived base stocks GE1-GE9, secondary
ether base stocks SE1 and SE2, and tertiary ether base stock TE1 of
formula (1), which may preferably be used in connection with the
present application, are shown in Table 2.
TABLE-US-00002 TABLE 2 Molecular Chemical Weight Formula Structure
GE1 466.87 C.sub.32H.sub.66O ##STR00047## GE2 466.87
C.sub.32H.sub.66O ##STR00048## GE3 522.97 C.sub.36H.sub.74O
##STR00049## GE4 466.87 C.sub.32H.sub.66O ##STR00050## GE5 410.76
C.sub.28H.sub.58O ##STR00051## GE6 466.87 C.sub.32H.sub.66O
##STR00052## GE7 522.57 C.sub.36H.sub.74O ##STR00053## GE8 382.42
C.sub.26H.sub.54O ##STR00054## GE9 466.51 C.sub.32H.sub.66O
##STR00055## GE10 410.76 C.sub.28H.sub.58O ##STR00056## GE12 382.71
C.sub.26H.sub.54O ##STR00057## GE14 410.76 C.sub.28H.sub.58O
##STR00058## GEIS 354.65 C.sub.24H.sub.50O ##STR00059## GE16 424.79
C.sub.29H.sub.60O ##STR00060## GE18 438.81 C.sub.30H.sub.62O
##STR00061## GE20 354.65 C.sub.24H.sub.50O ##STR00062## GE21 382.71
C.sub.26H.sub.54O ##STR00063## GE22 410.76 C.sub.28H.sub.58O
##STR00064## GE23 382.71 C.sub.26H.sub.54O ##STR00065## SE1 452.84
C.sub.31H.sub.64O ##STR00066## SE2 396.43 C.sub.27H.sub.56O
##STR00067## TE1 466.87 C.sub.32H.sub.66O ##STR00068##
Base Oils and Lubricant Compositions
[0269] The ether compounds of formula (A), or the subset thereof of
formula (1), are used as part of a base oil in accordance with the
present invention.
[0270] The base oils may contain an amount of compound of formula
(A), or a compound of the subset thereof of formula (1), which is
sufficient to impart beneficial properties of the compound onto the
base oil.
[0271] In some embodiments, the base oil comprises greater than
about 5%, such as greater than about 25%, greater than about 40%,
or greater than 50% by weight of ether compound of formula (A), or
the subset thereof of formula (1). The base oil may comprise up to
about 100%, such as up to about 90% of compound of formula (A), or
of the subset thereof of formula (1). The compound of formula (A),
or of the subset thereof of formula (1), in the base oil may be
composed of a single compound or a combination of compounds of
formula (A), or of the subset thereof of formula (1).
[0272] The remainder of the base oil may be made up with base
stocks which are not compounds of formula (A) and formula (1). Base
stocks other than those of formula (A) and formula (1) which are
suitable for use in the base oil include non-aqueous base stocks,
such as Group I, Group II, Group III, Group IV and Group V base
stocks. The remainder of the base oil may comprise a single base
stock or a combination of base stocks other than those of formula
(A) and formula (1).
The Base Oils are Used as Part of the Lubricant Composition in
Accordance with the Present Invention.
[0273] The lubricant compositions may contain an amount of base oil
which is sufficient to impart beneficial properties of the compound
of formula (A), or a compound of the subset thereof of formula (1),
onto the lubricating composition.
[0274] In some embodiments, the lubricant composition comprises
greater than about 50%, such as greater than about 65%, or greater
than about 80% by weight of base oil. The base oil may be composed
of a single base oil or a combination of base oils comprising
compound of formula (A), or of the subset thereof of formula
(1).
[0275] A particular advantage of the present invention relates to
the high temperature stability conferred to the lubricant
composition by the presence of ether compounds of formula (A), or
of the subset thereof of formula (1). The presence of at least one
molybdenum compound or at least one polymethacrylate compound is
better tolerated in the ether based compositions of the invention
compared to conventional non-ether compositions from a high
temperature stability perspective. Thus, the at least one
molybdenum compound or at least one polymethacrylate compound may
be used to enhance high temperature stability in the lubricant
compositions defined herein, or provide desirable properties to the
composition without impacting the high temperature stability of the
lubricant composition. For instance, molybdenum compounds are well
known to those skilled in the art of oil formulation to function as
friction modifiers to lower engine friction and promote fuel
economy. However, too high a level of molybdenum in conventional
non-ether compositions can contribute to deposits which can lead to
excess wear and shorten engine life. Similarly, polymethacrylates
are known for use as viscosity index improvers as well as pour
point depressants, but their use beyond a certain amount can lead
to unwanted deposit formation on hot surfaces of the engine, for
example turbochargers. The present invention allows the benefits of
molybdenum or polymethacrylate compounds to be taken advantage of
without lessening high temperature stability of the lubricant
composition to the same extent as in conventional non-ether based
compositions and the presence of molybdenum or polymethacrylate
compounds has been found to enhance high temperature stability in
some cases.
[0276] Particular problems associated with a lack of high
temperature stability is engine scuffing, in particular, piston
scuffing and deposits in high temperature regions of the engine,
particularly in the turbochargers. ASTM Terminology standard G40
defines scuffing as a form of wear occurring in
inadequately-lubricated tribosystems that is characterized by
macroscopically observable changes in texture, with features
related to the direction of motion. Engine scuffing is
intrinsically linked with the presence of deposits in high
temperature regions of the engine and therefore scuffing can be
impacted by the choice of lubricant oil that is used for
lubricating the engine. Where reference is made herein to piston
scuffing or piston system scuffing, it will be appreciated that
this refers to scuffing on the piston ring, skirt or cylinder
liner.
[0277] Whether or not an engine oil is likely to give rise to
engine scuffing may be determined by means of the Komatsu hot-tube
test (KHT), which corresponds to standard method, JPI-5S-55-99. The
KHT test evaluates the high temperature stability of a lubricant
and is described in detail in: Ohkawa, S., Seto, K., Nakashima, T.,
and Takase, K., ""Hot Tube Test"-Analysis of Lubricant Effect on
Diesel Engine Scuffing," SAE Technical Paper 840262, 1984,
doi:10.4271/840262. In the KHT test, droplets of a candidate oil
are forced by air up inside a heated narrow glass capillary tube
and the thin film oxidative stability of the lubricant is measured
by the degree of lacquer formation on the glass tube, the resulting
colour of the tube being rated on a scale of 0 to 10.
[0278] The results of the KHT test correspond to deposit merit
ratings which can be related to engine scuffing as described in the
above paper. A deposit merit rating of 0 refers to heavy deposit
formation whilst a deposit merit rating of 10 means a clean glass
tube at the end of the test. The level of lacquer formation in the
tube reflects the high temperature stability of the oil and its
tendency during service to form deposits in high temperature
regions of the engine, thereby causing scuffing. Engine oils which
pass the KHT test will have lower propensity to cause scuffing
engine failure in Heavy Duty applications from scuffing as a result
of deposits.
[0279] The KHT test also evaluates the `hot surface deposit
control`, which includes surfaces associated with turbochargers,
for JASO engine oil specifications (DH-1-05, DH-2-08, DH-1-08,
available in document JASO M 355:2008). `Engine Failure Analysis:
Internal Combustion Engine Failures and Their Causes` by Ernst
Greuter and Stefan Zima, published by SAE International, 2012, page
493, ISBN 978-0-7860-0885-2, also describes carbon deposit
formation on turbochargers as a result of hot surface deposit
formation and supports the connection between hot surface deposits
and engine scuffing which underlies the KHT test.
[0280] The Thermo-oxidation Engine oil Simulation Test (TEOST) 33C,
which corresponds to standard method ASTM D6335, is a bench test
which simulates the oxidation and carbonaceous deposit-forming
characteristics of engine oils in the turbochargers of modern
high-performance engines. The TEOST 33C test generates physical
measurements of deposits and represents another test through which
to determine an oil's susceptibility to deposit formation in the
turbochargers specifically. Hot Liquid Process Simulator (HLPS)
testing may also be used as a means for characterising the
propensity of an oil to create deposits in an engine by running oil
over a hot surface.
[0281] Lubricant compositions according to the present invention
have been found to outperform corresponding conventional non-ether
based compositions in KHT and HLPS testing without adversely
affecting the TEOST 33C, indicating that the ether compositions of
the invention have greater high temperature stability than
conventional lubricant compositions differing only in the absence
of ether base stock. Moreover, the presence of at least one
molybdenum compound or at least one polymethacrylate compound in
accordance with the present invention is better tolerated in the
ether compositions of the present invention than in corresponding
conventional non-ether based compositions.
[0282] The lubricant composition according to the invention
comprises the at least one molybdenum compound, on a molybdenum
element basis, in an amount of at least 0.06% by weight of the
lubricant composition, when present. Alternatively, the lubricant
composition according to the invention comprises the at least one
polymethacrylate compound in an amount of from 0.1 to 7.5% by
weight of the lubricant composition, when present.
[0283] In preferred embodiments, when the lubricant composition
comprises at least one molybdenum compound as a lubricant additive,
the at least one molybdenum compound is present, on a molybdenum
element basis, in an amount from 0.06% to 0.25%, from 0.075% to
0.175%, or from 0.075% to 0.125%, by weight of the lubricant
composition. The amount of molybdenum element present in the
lubricant compositions of the invention may, for example, be
determined according to method ASTM D5185.
[0284] In preferred embodiments, when the lubricant composition
comprises at least one polymethacrylate compound as a lubricant
additive, the at least one polymethacrylate compound is present in
an amount of from 0.25 to 7%, from 1 to 6%, from 2 to 4% by weight
of the lubricant composition.
[0285] In some embodiments, the lubricant composition comprises at
least one molybdenum compound. Any molybdenum compound may be used
which is suitable for use as an additive for a lubricant
composition intended for use in an internal combustion engine. As
will be appreciated, the term "molybdenum compound" used herein
refers to a molybdenum-containing compound or complex, which has
oil-solubility or oil-dispersibility properties. Molybdenum
compounds for use in the lubricant compositions of the present
invention include organo molybdenum compounds, molybdenum
dialkyldithiocarbamates, molybdenum dialkylthiophosphates,
molybdenum disulphide, tri-molybdenum cluster
dialkyldithiocarbamates, non-sulphur molybdenum compounds and the
like. Suitable molybdenum-containing compounds are described for
example, in EP 1533362 A1, for example, in paragraphs [0101] to
[0117]. Certain molybdenum compounds of these classes are well
known to have friction modifier properties in lubricant
compositions.
[0286] Particularly preferred molybdenum compounds for use in the
present invention are molybdenum-sulfur compounds, particularly
tri-nuclear molybdenum-sulfur cluster compounds as, for instance,
described in EP 1 040 115 and WO 99/31113. Further, examples of
trinuclear molybdenum-sulfur compounds are also disclosed in
WO98/26030, WO99/31113, WO99/66013, EP 1 138 752 and EP 1 138 686.
As the skilled person will be aware, such compounds may be added to
a base oil fully formed or such compounds may be formed in situ as
a result of the presence of sulfur-containing compounds or
complexes (e.g. ZDDP), for example by means of ligand exchange.
[0287] In some embodiments, the lubricant composition comprises a
polymethacrylate compound. The term "polymethacrylate compound"
used herein refers to poly(methylacrylate) homopolymers of various
chain lengths as well as homo- and co-polymers of various chain
length alkyl methacrylates. Such compounds are in some cases known
for their viscosity index improver and/or pour point depressant
properties. Suitable number average molecular weights for the at
least one polymethacrylate compound are from about 15,000 to about
1,000,000, for example about 20,000 to about 600,000, as determined
by gel permeation chromatography or light scattering methods. As
the skilled person will appreciate, polymethacrylate compounds may
be added to a base oil composition in preparation of the lubricant
composition in the form of a solid or as a solution with the
polymethacyrlate dissolved in suitable solvent. Reference herein to
an amount of at least one polymethacrylate compound included in the
lubricant composition is to be understood as referring to the
weight of polymethacrylate compound employed itself, without any
dilution.
[0288] In some embodiments, the at least one polymethacrlyate
compound may be a comb-type polymer. As the skilled person is
aware, a comb-type polymer refers to a polymer having a linear main
chain (back bone) with a number of branches along the chain.
[0289] In some embodiments, the at least one polymethacrylate
compound may be functionalized. As the skilled person is aware,
"functionalized" in this context refers to a polymethacrylate
compound with modified side chains for the purpose of imparting
dispersancy to the polymer or for conferring properties of a pour
point depressant. For example, preferred functionalized
polymethacrylate compounds contain amine functionality (e.g.
N,N-dialkylaminoalkyl(meth)acrylamide units).
[0290] Hot Liquid Process Simulator (HLPS) testing has also
indicated that particular detergents, specifically phenate and
neutral sulphonate detergents, can also enhance the high
temperature stability of the ether compositions to a far greater
degree than the enhancement which is observed in conventional
non-ether based compositions. Thus, in a further aspect, the
present invention also provides a lubricant composition for an
internal combustion engine comprising a base oil of lubricating
viscosity, wherein the base oil comprises an ether base stock of
formula (A):
##STR00069##
[0291] where: R.sub.a and R.sub.b are aliphatic hydrocarbyl groups
and may be the same or different; wherein at least one of R.sub.a
and R.sub.b is branched-chain alkyl, alkoxy-substituted-alkyl or
cycloalkyl-substituted-alkyl;
[0292] the lubricant composition further comprising: [0293] a) at
least one phenate detergent; and/or [0294] b) at least one neutral
sulphonate detergent.
[0295] As the skilled person will appreciate, preferred embodiments
relating to components of the lubricant compositions according to
the first aspect of the invention apply equally to the lubricant
compositions according to this further aspect of the invention.
[0296] Metallic and non-metallic phenate and neutral sulphonate
detergents may be used in accordance with this aspect of the
invention.
[0297] Neutral and overbased metal phenate detergents are
well-known for their use as lubricant additives (overbased
compounds containing more than the stoichiometric amount of metal
required to react with the phenol in order to prepare the metal
phenate). Metal phenates include alkali or alkaline earth metal
phenates, preferably wherein the metal is selected from barium,
sodium, potassium, lithium, calcium, and magnesium, most preferably
calcium and magnesium. Phenols employed in the preparation of
phenate detergents include hydrocarbyl substituted phenols, such as
para-substituted phenols, phenols with more than one hydroxyl
group, phenols with fused aromatic rings and/or alkylene bridged
biphenols, any of which may be sulphurised (for example, mono- and
di-sulphide bridged biphenols). Suitable phenate detergents for use
in the present invention include those described, for example, in
U.S. Pat. Nos. 4,221,673, 4,104,180 and 4,973,411.
[0298] The phenate detergent may have a base number (BN) of from
0.1 to 400 mg KOH/g, or from 50 to 200 mg KOH/g, for example 150 mg
KOH/g, as measured in accordance with ASTM D2896. In preferred
embodiments, an overbased phenate detergent is employed having a
base number (BN) of from 150 to 400 mg KOH/g, preferably 200 to 300
mg KOH/g, for example from 240 to 260 mg KOH/g, as measured in
accordance with ASTM D2896.
[0299] Neutral metal sulphonate detergents are well-known for their
use as lubricant additives and include alkali or alkaline earth
metal sulphonates, preferably wherein the metal is selected from
barium, sodium, potassium, lithium, calcium, and magnesium, most
preferably calcium and magnesium. Neutral sulphonates for use in
the present invention may have a TBN of less than 60 mg KOH/g,
preferably less than 40 mg KOH/g, as measured in accordance with
ASTM D2896. Suitably sulphonates may be prepared from sulfonic
acids which are typically obtained by the sulphonation of alkyl
substituted aromatic hydrocarbons, such as those obtained by
alkylating benzene, toluene, xylene, naphthalene, diphenyl or their
halogen derivatives such as chlorobenzene, chlorotoluene and
chloronaphthalene. The alkyl substituted aryl sulphonates typically
contain from about 9 to about 80 or more carbon atoms, preferably
from about 16 to about 60 carbon atoms.
[0300] Where the lubricant composition according to the different
aspects of the invention comprises a phenate detergent, preferably
the phenate detergent is present in an amount of from 0.1 to 5%,
more preferably in an amount of from 0.25 to 2.5%, most preferably
in an amount of from 0.5 to 1.5%, by weight of the lubricant
composition.
[0301] Where the lubricant composition according to the different
aspects of the invention comprises a neutral sulphonate detergent,
preferably the neutral sulphonate detergent is present in an amount
of from 0.01 to 5%, more preferably in an amount of from 0.1 to
2.5%, most preferably in an amount of from 0.25 to 1.5%, by weight
of the lubricant composition.
[0302] The lubricant compositions according to the present
invention may also comprise additional lubricant additives, in
addition to those referred to herein (i.e. the at least one
molybdenum compound/polymethacrylate compound or neutral
sulphonate/phenate detergent). The additional lubricant additives
will typically be present in the lubricant composition in an amount
of from about 2% to about 40% by weight, such as about 5% to about
30% by weight.
[0303] Suitable additional lubricant additives include detergents
(including metallic and non-metallic detergents), friction
modifiers, viscosity modifiers, dispersants (including metallic and
non-metallic dispersants), dispersant viscosity modifiers,
viscosity index improvers, pour point depressants, anti-wear
additives, rust inhibitors, corrosion inhibitors, antioxidants
(sometimes also called oxidation inhibitors), anti-foams (sometimes
also called anti-foaming agents), seal swell agents (sometimes also
called seal compatibility agents), extreme pressure additives
(including metallic, non-metallic, phosphorus containing,
non-phosphorus containing, sulphur containing and non-sulphur
containing extreme pressure additives), surfactants, demulsifiers,
anti-seizure agents, wax modifiers, lubricity agents, anti-staining
agents, chromophoric agents, metal deactivators, and mixtures of
two or more thereof.
[0304] In some embodiments, the lubricant composition comprises a
detergent. Examples of detergents include ashless detergents (that
is, non-metal containing detergents) and metal-containing
detergents. Suitable non-metallic detergents are described for
example in U.S. Pat. No. 7,622,431. Metal-containing detergents
comprise at least one metal salt of at least one organic acid,
which is called soap or surfactant. Suitable organic acids include
for example, sulphonic acids, phenols (suitably sulphurised and
including for example, phenols with more than one hydroxyl group,
phenols with fused aromatic rings, phenols which have been modified
for example, alkylene bridged phenols, and Mannich base-condensed
phenols and saligenin-type phenols, produced for example by
reaction of phenol and an aldehyde under basic conditions) and
sulphurised derivatives thereof, and carboxylic acids including for
example, aromatic carboxylic acids (for example
hydrocarbyl-substituted salicylic acids and derivatives thereof,
for example hydrocarbyl substituted salicylic acids and sulphurised
derivatives thereof).
[0305] In some embodiments, the lubricant composition comprises a
friction modifier. Suitable friction modifiers include for example,
ash-producing additives and ashless additives. Examples of suitable
friction modifiers include fatty acid derivatives including for
example, fatty acid esters, amides, amines, and ethoxylated amines.
Examples of suitable ester friction modifiers include esters of
glycerol for example, mono-, di-, and tri-oleates, mono-palmitates
and mono-myristates. A particularly suitable fatty acid ester
friction modifier is glycerol monooleate. Examples of suitable
friction modifiers also include molybdenum compounds for example,
organo molybdenum compounds, molybdenum dialkyldithiocarbamates,
molybdenum dialkylthiophosphates, molybdenum disulphide,
tri-molybdenum cluster dialkyldithiocarbamates, non-sulphur
molybdenum compounds and the like. Suitable molybdenum-containing
compounds are described for example, in EP 1533362 A1 for example
in paragraphs [0101] to [0117]. As the skilled person will
appreciate, where the lubricant composition comprises the at least
one molybdenum compound, additional molybdenum-containing compounds
may be present which are added, in particular, for their friction
modifier properties. Alternatively, the presence of additional
molybdenum compounds may be unnecessary.
[0306] In some embodiments, the lubricant composition comprises a
dispersant. Examples of suitable ashless dispersants include oil
soluble salts, esters, amino-esters, amides, imides and oxazolines
of long chain hydrocarbon-substituted mono- and polycarboxylic
acids or anhydrides thereof; thiocarboxylate derivatives of long
chain hydrocarbons; long chain aliphatic hydrocarbons containing
polyamine moieties attached directly thereto; Mannich condensation
products formed by condensing a long chain substituted phenol with
formaldehyde and polyalkylene polyamine; Koch reaction products and
the like. Particularly preferred dispersants for use in the present
invention are long chain aliphatic hydrocarbons containing
polyamine moieties attached directly thereto such as
polyisobutylene succinyl anhydride-polyamines (PIBSA-PAM).
[0307] Advantageously, borated dispersants may also be used in the
lubricant compositions of the present invention without negatively
impacting oxidative stability. In some embodiments, the lubricant
composition may contain boron in an amount from 0.005 wt. % to 0.05
wt. %, preferably from 0.015 wt. % to 0.035 wt. %. This level of
elemental boron may be derived from the use of a borated
dispersants and/or boron-containing anti-wear additives or
otherwise.
[0308] In some embodiments, the lubricant composition comprises a
dispersant viscosity modifier. Examples of suitable dispersant
viscosity modifiers and methods of making them are described in WO
99/21902, WO 2003/099890 and WO 2006/099250.
[0309] In some embodiments, the lubricant composition comprises a
viscosity index improver. Examples of suitable viscosity modifiers
include high molecular weight hydrocarbon polymers (for example
polyisobutylene, copolymers of ethylene and propylene and higher
alpha-olefins); polyesters (for example polymethacrylates);
hydrogenated poly(styrene-co-butadiene or isoprene) polymers and
modifications (for example star polymers); and esterified
poly(styrene-co-maleic anhydride) polymers. Oil-soluble viscosity
modifying polymers generally exhibit number average molecular
weights of at least about 15,000 to about 1,000,000, such as about
20,000 to about 600,000 as determined by gel permeation
chromatography or light scattering methods. As the skilled person
will appreciate, where the lubricant composition comprises the at
least one polymethacrylate compound, additional methacrylate
polymers may be present which are added, in particular, for their
viscosity index improver properties. Alternatively, the presence of
additional methacrylate polymers may be unnecessary.
[0310] In some embodiments, the lubricant composition comprises a
pour point depressant. Examples of suitable pour point depressants
include C.sub.8 to C.sub.18 dialkyl fumarate/vinyl acetate
copolymers, methacrylates, polyacrylates, polyarylamides,
polymethacrylates, polyalkyl methacrylates, vinyl fumarates,
styrene esters, condensation products of haloparaffin waxes and
aromatic compounds, vinyl carboxylate polymers, terpolymers of
dialkyfumarates, vinyl esters of fatty acids and allyl vinyl
ethers, wax naphthalene and the like. As the skilled person will
appreciate, where the lubricant composition comprises the at least
one polymethacrylate compound, additional methacrylate polymers may
be present which are added, in particular, for their pour point
depressant properties. Alternatively, the presence of additional
methacrylate polymers may be unnecessary.
[0311] In some embodiments, the lubricant composition comprises at
least one anti-wear additive. Examples of suitable anti-wear
additives include non-phosphorus containing additives for example,
sulphurised olefins. Examples of suitable anti-wear additives also
include phosphorus-containing anti-wear additives. Examples of
suitable ashless phosphorus-containing anti-wear additives include
trilauryl phosphite and triphenylphosphorothionate and those
disclosed in paragraph [0036] of US 2005/0198894. Examples of
suitable ash-forming, phosphorus-containing anti-wear additives
include dihydrocarbyl dithiophosphate metal salts. Examples of
suitable metals of the dihydrocarbyl dithiophosphate metal salts
include alkali and alkaline earth metals, aluminium, lead, tin,
molybdenum, manganese, nickel, copper and zinc. Particularly
suitable dihydrocarbyl dithiophosphate metal salts are zinc
dihydrocarbyl dithiophosphates (ZDDP). As the skilled person will
appreciate, where the lubricant composition comprises the at least
one molybdenum compound, additional molybdenum-containing compounds
may be present which are added, in particular, for their anti-wear
properties. Alternatively, the presence of additional molybdenum
compounds may be unnecessary.
[0312] In some embodiments, the amount of phosphorus contained in
the lubricant composition is less than 0.5 wt. %, preferably from
0.001 to 0.3 wt. %, more preferably from 0.025 to 0.2 wt. %, based
on the total weight of the lubricant composition.
[0313] In some embodiments, the lubricant composition comprises a
rust inhibitor. Examples of suitable rust inhibitors include
non-ionic polyoxyalkylene polyols and esters thereof,
polyoxyalkylene phenols, polyoxyalkylene polyols, anionic alky
sulphonic acids, zinc dithiophosphates, metal phenolates, basic
metal sulphonates, fatty acids and amines.
[0314] In some embodiments, the lubricant composition comprises a
corrosion inhibitor. Examples of suitable corrosion inhibitors
include phosphosulphurised hydrocarbons and the products obtained
by the reaction of phosphosulphurised hydrocarbon with an alkaline
earth metal oxide or hydroxide, non-ionic polyoxyalkylene polyols
and esters thereof, polyoxyalkylene phenols, thiadiazoles,
triazoles and anionic alkyl sulphonic acids. Examples of suitable
epoxidised ester corrosion inhibitors are described in US
2006/0090393.
[0315] In some embodiments, the lubricant composition comprises an
antioxidant. Examples of suitable antioxidants include alkylated
diphenylamines, N-alkylated phenylenediamines,
phenyl-a-naphthylamine, alkylated phenyl-a-naphthylamines,
dimethylquinolines, trimethyldihydroquinolines and oligomeric
compositions derived therefrom, hindered phenolics (including
ashless (metal-free) phenolic compounds and neutral and basic metal
salts of certain phenolic compounds), aromatic amines (including
alkylated and non-alkylated aromatic amines), sulphurised alkyl
phenols and alkali and alkaline earth metal salts thereof,
alkylated hydroquinones, hydroxylated thiodiphenyl ethers,
alkylidenebisphenols, thiopropionates, metallic dithiocarbamates,
1,3,4-dimercaptothiadiazole and derivatives, oil soluble copper
compounds (for example, copper dihydrocarbyl thio- or
thio-phosphate, copper salts of a synthetic or natural carboxylic
acids, for example a C.sub.8 to C.sub.18 fatty acid, an unsaturated
acid or a branched carboxylic acid, for example basic, neutral or
acidic Cu(I) and/or Cu(II) salts derived from alkenyl succinic
acids or anhydrides), alkaline earth metal salts of
alkylphenolthioesters, suitably containing C.sub.5 to C.sub.12
alkyl side chains, calcium nonylphenol sulphide, barium
t-octylphenyl sulphide, dioctylphenylamine, phosphosulphised or
sulphurised hydrocarbons, oil soluble phenates, oil soluble
sulphurised phenates, calcium dodecylphenol sulphide,
phosphosulphurised hydrocarbons, sulphurised hydrocarbons,
phosphorus esters, low sulphur peroxide decomposers and the
like.
[0316] In some embodiments, the lubricant composition comprises an
antifoam agent. Examples of suitable anti-foam agents include
silicones, organic polymers, siloxanes (including poly siloxanes
and (poly) dimethyl siloxanes, phenyl methyl siloxanes), acrylates
and the like.
[0317] In some embodiments, the lubricant composition comprises a
seal swell agent. Examples of suitable seal swell agents include
long chain organic acids, organic phosphates, aromatic esters,
aromatic hydrocarbons, esters (for example butylbenzyl phthalate)
and polybutenyl succinic anhydride.
[0318] The lubricant composition may comprise lubricant additives
in the amounts shown in Table 3.
TABLE-US-00003 TABLE 3 Lubricant composition Suitable amount
(actives) if Preferred amount (actives) if Additive type present by
weight present by weight Phosphorus-containing Corresponding to
about 10 to Corresponding to about 10 to anti-wear additives about
6000 ppm P about 1000 ppm P Molybdenum-containing Corresponding to
about 10 to Corresponding to about 40 to anti-wear additives about
1000 ppm Mo about 600 ppm Mo Boron-containing anti- Corresponding
to about 10 to Corresponding to about 50 to wear additives about
500 ppm B about 100 ppm B Friction modifiers About 0.01 to about 5%
About 0.01 to about 1.5% Molybdenum-containing Corresponding to
about 10 to Corresponding to about 400 friction modifiers about
1000 ppm Mo to about 600 ppm Mo Molybdenum-containing Corresponding
to about 10 to Corresponding to about 40 to additives (e.g. both
anti- about 2000 ppm Mo about 1200 ppm Mo wear additives and
friction modifiers) Dispersants About 0.1 to about 20% About 0.1 to
about 8% Detergents About 0.01 to about 6% About 0.01 to about 4%
Viscosity index improvers About 0.01 to about 20% About 0.01 to
about 15% Pour point depressants About 0.01 to about 5% About 0.01
to about 1.5% Corrosion and/or rust About 0.01 to about 5% About
0.01 to about 1.5% inhibitors Anti-oxidants About 0.01 to about 10%
About 0.5 to 5 about % Antifoams containing Corresponding to about
1 to Corresponding to about 1 to silicon about 20 ppm Si about 10
ppm Si
[0319] The lubricant compositions may have a kinematic viscosity at
40.degree. C. of less than about 60 cSt, such as less than about 55
cSt, or less than about 50 cSt. The lubricant compositions may have
a kinematic viscosity at 100.degree. C. of less than about 12 cSt,
such as less than about 10 cSt, or less than about 9.5 cSt. The
lubricant compositions may have a viscosity index of greater than
about 100, such as greater than about 110, or greater than about
120. The kinematic viscosity at 40.degree. C. and the kinematic
viscosity at 100.degree. C. may be measured according to ASTM D445.
The viscosity index may be calculated according to ASTM D2270.
[0320] The lubricant compositions may have a Noack volatility of
less than about 25%, such as less than about 15%, or less than
about 10% by weight. Noack volatility may be measured according to
CEC-L-40-A-93.
[0321] The lubricant compositions may have a viscosity at
150.degree. C. and a shear rate of 10.sup.6 s.sup.-1 of no greater
than 3 cP, such as no greater than 2.8 cP. This high temperature
high shear viscosity may be measured according to
CEC-L-36-A-90.
[0322] The lubricant composition may have at least one of: [0323]
an oxidative stability performance on a CEC-L-088-02 test indicated
by an absolute viscosity increase at 40.degree. C. of no more than
45 cSt, such as no more than 35 cSt or no more than 25 cSt; an
oxidative stability performance on a CEC-L-109-14 test indicated by
an increase in kinematic viscosity at 100.degree. C. of less than
200%, preferably less than 150%; a fuel economy performance on a
CEC-L-054-96 test of at least 2.5%, such as at least 3%; a piston
cleanliness performance on a CEC-L-088-02 test indicated by an
overall piston merit of at least 8.5, such as 9; and a high
temperature stability performance on a KHT test at 280.degree. C.
in accordance with JPI-5S-55-99 indicated by an overall deposit
merit of at least 7.0
[0324] The lubricant compositions may have a cold-crankcase
simulator performance at -30.degree. C. of less than about 3000,
such as less than about 2800, or less than about 2750, for example
as measured according to ASTM D5293.
[0325] Preferred lubricant compositions meet the requirements set
out in SAE J300.
[0326] The lubricant compositions may be used in a method of
lubricating a surface.
[0327] Suitable surfaces include those in power transmission
systems for example drive lines and gear boxes for example for
vehicles including for example passenger vehicles and heavy duty
vehicles; and those in internal combustion engines, for example the
crankcases of internal combustion engines. Suitable surfaces also
include those in turbine bearings for example in water turbine
bearings.
[0328] Suitable internal combustion engines include, for example,
engines used in automotive applications, engines used in marine
applications and engines used in land-based power generation
plants. The lubricant compositions are particularly suited to use
in an automotive internal combustion engine.
[0329] The lubricant compositions may be used to improve the fuel
economy and/or piston cleanliness performance and/or turbocharger
cleanliness performance of an internal combustion engine and/or a
vehicle, such as an automotive vehicle associated with an internal
combustion engine. Accordingly, there are provided methods of
improving the fuel economy and/or piston cleanliness performance
and/or turbocharger cleanliness performance of an internal
combustion engine and/or a vehicle, such as an automotive vehicle
associated with an internal combustion engine, comprising the step
of providing or supplying to the engine and/or vehicle at least one
of the lubricant compositions.
[0330] The invention will now be described with reference to the
accompanying figures and examples, which are not limiting in
nature, in which:
[0331] FIG. 1 is a graph of Maximum Deposit Thickness (MDT)
observed in HLPS analysis of blended compositions containing
Guerbet-derived base stock (GE3) and/or a Group III base stock
(Yubase 4) together with different detergents; and
[0332] FIG. 2 is a graph of deposit volume
(cm.sup.3.times.10.sup.-17) observed in HLPS analysis of blended
compositions containing Guerbet-derived base stock (GE3) and/or a
Group III base stock (Yubase 4) together with different
detergents.
EXAMPLES
Example 1
Properties of Ether Base Stocks
[0333] Guerbet-derived base stock GE3 of formula (1) was prepared,
the structure of which is shown in Table 4.
TABLE-US-00004 TABLE 4 Molecular Chemical Weight Formula Structure
GE3 522.97 C.sub.36H.sub.74O ##STR00070##
The Following Properties of the Base Stock were Tested:
[0334] Kinematic viscosity at 100.degree. C. (KV100) and kinematic
viscosity at 40.degree. C. (KV40) were tested according to ASTM
D7279.
[0335] Viscosity index (VI) was calculated according to ASTM
D2270.
[0336] Pour point was determined according to ASTM D7346.
[0337] Differential scanning calorimetry (DSC) oxidation onset
temperature was tested using a method which was based on ASTM E2009
(method B). According to the method, the base stocks were heated
from 50.degree. C. to 300.degree. C., at a rate of 50.degree.
C./minute, under a pressure of 500 psi in an aluminium SFI pan. The
temperature at which an exotherm was observed was recorded.
[0338] Noack volatility was measured using a method which was based
on IP 393 and was considered similar to CEC-L-40-A-93. According to
the method, reference oils of known Noack volatility were heated
from 40.degree. C. to 550.degree. C. to determine the temperature
at which the Noack volatility weight loss of each of the reference
oils was reached. The base stocks were subjected to the same
process as the reference oils. The Noack weight of the base stocks
could be determined based on the results obtained from the
reference oils.
[0339] The results of the tests are summarized in Table 5, together
with results obtained from a conventional base stock (Yubase 4, a
Group III base stock).
TABLE-US-00005 TABLE 5 DSC Noack Pour Oxidation volatility KV100
KV40 Point Onset T (% by (cSt) (cSt) VI (.degree. C.) (.degree. C.)
weight) GE3 3.9 16.0 143 -42 202.89 2.4 Yubase 4 4.2 19.2 126 -12
220.00 11.7
[0340] It can be seen that the Guerbet-derived base stock ether has
a lower volatility, lower pour point and lower kinematic viscosity
as compared to the conventional base oil, although the DSC
oxidation onset temperature is lower in Guerbet-derived base stock
than the conventional based oil.
Example 2
Properties of Lubricant Compositions Containing Ether Base
Stocks
[0341] Guerbet-derived ether base stock GE3 was blended with
conventional base oil additives (additive A, a commercially
available additive package providing a dispersant level
representative of high performance engine oil between 7 and 10 wt %
based on the total weight of the lubricant composition; additive B,
a cold-flow improver; additive C, an oxidation inhibitor; and
additive D, a viscosity index improver) and conventional base oils
(Yubase 4, a Group III base oil; and Yubase 6, a Group III base
oil) to form a lubricant blend. A Baseline blend was also prepared.
Yubase 4 was chosen as the main component of the Baseline blend,
since it exhibits a similar KV100 to Guerbet-derived ether base
stock, GE3. The Baseline blend was believed to be a stringent
baseline for comparison, since it is a 5W-30 formulation which
meets certain specifications (ACEA A5/B5, API-SN/GF-4). The details
of the blended compositions are shown in Table 6 in % by
weight.
TABLE-US-00006 TABLE 6 Baseline blend GE3 blend Additive A 16.4
16.4 Additive B 0.15 0.15 Additive C 0.1 0.1 Additive D 4 4 Yubase
4 67.45 17.45 Yubase 6 11.9 11.9 GE3 0 50
[0342] No problems with miscibility were encountered during
preparation of the blended compositions.
[0343] The blended compositions were tested to see whether the
advantageous properties of the base stocks would be reflected in a
fully formulated lubricant composition. The following properties
were tested:
[0344] Kinematic viscosity at 100.degree. C. (KV100) and kinematic
viscosity at 40.degree. C. (KV40) were tested according to ASTM
D445 (part of SAE J300).
[0345] Viscosity index (VI) was calculated according to ASTM
D2270.
[0346] Cold-cranking simulator (CCS) analysis was carried out at
-30.degree. C. according to ASTM D5293 (part of SAE J300).
[0347] High temperature high shear (HTHS) analysis was carried out
according to CEC-L-36-A-90.
[0348] Total base number (TBN) was determined according to ASTM
D2896.
[0349] Noack volatility was tested according to CEC-L-40-A-93.
[0350] Sulphated ash content was measured according to IP 163.
[0351] The results of the tests are summarized in Table 7.
TABLE-US-00007 TABLE 7 Baseline blend GE3 blend KV40 (cSt) 53.59
44.63 KV100 (cSt) 9.542 8.688 VI 164 177 CCS -30.degree. C. (cP)
4656 2702 HTHS (cP) 2.98 2.75 TBN (mg KOH/g) 11.66 11.44 NOACK (%
by weight) 11.2 9.7 Sulphated ash (%) 1.22 1.27
[0352] It can be seen that the properties of the Guerbet-derived
base stock are also exhibited in the blended composition. In
particular, beneficial viscosity, volatility and cold-flow
properties are observed. The Guerbet-derived base stock also
exhibited similar HTHS measurements, TBNs and sulphated ash
contents to the Baseline blend.
Example 3
Komatsu Hot-Tube (KHT) Test
[0353] Fully formulated compositions comprising Guerbet-derived
base stock (GE3) and/or a Group III base stock (Yubase 4) together
with varying amounts of a molybdenum-sulfur compound and/or a
polymethacrylate compound (a comb-type copolymer of alkyl
methacrylates in solution--approximately 1:1 dilution ratio) as
well as additional lubricant additives including (non-borated)
dispersant, ZDDP, detergents, antioxidants and viscosity modifier
(VM) were subjected to the KHT test in accordance with JPI-5S-55-99
and SAE Technical Paper 840262. Results obtained from the KHT
testing in the form of deposit merits are shown in Table 8
(compositional data shown in % by weight).
TABLE-US-00008 TABLE 8 Lubricant Composition 1 2 3 4 5 6 Yubase 4
83.683 33.683 81.925 31.925 83.685 33.685 GE3 ether 50 50 50
Phenolic AO 0.5 0.5 0.5 0.5 0.5 0.5 Aminic AO 0.1 0.1 0.1 0.1 0.1
0.1 Detergents 2.18 2.18 2.18 2.18 2.18 2.18 Dispersant 6 6 6 6 6 6
ZDDP 0.535 0.535 0.535 0.535 0.535 0.535 VM 7 7 7 7 Antifoam 0.002
0.002 PMA 7 7 Mo--S 1.76 1.76 compound Mo (elemental, 0.08 0.08 wt.
%) KHT 3 7.5 6.5 6.5 6.5 7.5 rating
[0354] According to the results of the KHT testing, the ether
containing lubricant composition 2 exhibits a significantly higher
KHT merit rating (7.5) compared to that of the non-ether containing
lubricant composition 1. These results indicate that the presence
of the ether confers a benefit in reducing high temperature induced
deposit formation which would otherwise lead to scuffing. In
addition, the ether-containing lubricant composition 4, containing
an amount of 0.08 wt. % of molybdenum, exhibits the same KHT
deposit merit rating (6.5) as the corresponding non-ether
containing composition 3. This is particularly advantageous since
the ether composition exhibits a lower viscosity profile than the
non-ether composition and yet exhibits equivalent high temperature
stability. This means that a benefit may be seen in terms of fuel
economy through the use of the ether composition of the invention
over a conventional non-ether containing composition without any
accompanying increase in turbocharger deposits and piston scuffing.
As discussed in more detail below, the results in the TEOST 33C
testing also demonstrate that the presence of molybdenum impacts
deposit formation in ether-containing compositions to no more of a
degree than the non-ether containing compositions despite the DSC
oxidation onset temperature of the ether base stock being lower
than that of the conventional Group III base stock as demonstrated
in Example 1.
[0355] The results of the KHT testing also demonstrate a
significant advantage in the presence of the at least one
polymethacrylate compound, particular in the case of the
ether-containing compositions. For instance, the ether-containing
lubricant composition 6 also containing a polymethacrylate compound
exhibits a substantially higher deposit merit rating (7.5) in the
KHT test compared to the non-ether containing composition 5. Thus,
when the at least one polymethacrylate compound is present, the
ether composition is able to out-perform the corresponding
non-ether composition in terms of high temperature stability. This
is of particular benefit since the ether composition exhibits a
lower viscosity profile than the non-ether composition and so the
present invention is able to benefit from increased fuel economy
without increasing deposits in hot regions of the engine, such as
in turbochargers, or causing piston scuffing which would otherwise
shorten engine lifetime.
Example 4
TEOST 33C Test
[0356] Fully formulated compositions comprising Guerbet-derived
base stock (GE3) and/or a Group III base stock (Yubase 4) together
with varying amounts of a molybdenum-sulfur compound and/or a
polymethacrylate (a comb-type copolymer of alkyl methacrylates in
solution--approximately 1:1 dilution ratio) as well as additional
lubricant additives including (non-borated) dispersant, ZDDP,
detergents, antioxidants and viscosity index modifier (VIM) were
subjected to the TEOST 33C test in accordance with standard method
ASTM D6335. Results obtained from the TEOST 33C testing in the form
of total deposits (in turbochargers) are shown in Table 9
(compositional data shown in % by weight).
TABLE-US-00009 TABLE 9 Lubricant Composition A B C D E F G H I J K
Yubase 4 83.593 89.273 87.793 84.193 84.873 86.533 85.823 83.783
82.993 33.87 32.99 GE3 ether 50 50 Phenolic AO 0.5 0 0 0 0 0 0 0.5
0.5 0.5 0.5 Aminic AO 0.2 0.1 0.5 0.1 0.5 0.3 1 1 1 1 1 Sulphonate
(400BN) 0.86 0.43 0.86 0.86 0.43 0.64 0.65 0.43 0.43 0.43 0.43
Sulphonate (neutral) 0.34 0.17 0.34 0.34 0.17 0.26 0.26 0.17 0.17
0.17 0.17 Phenate (150BN) 0.97 0.49 0.97 0.97 0.49 0.73 0.73 0.49
0.49 0.49 0.49 Dispersant 6 2 2 6 6 4 4 6 6 6 6 ZDDP 0.535 0.535
0.535 0.535 0.535 0.535 0.535 0.535 0.535 0.535 0.535 VIM 7 7 7 7 7
7 7 Antifoam 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002
0.002 0.002 PMA 7 7 7 7 Mo--S compound 0.88 0.88 Mo (elemental, wt.
%) 0.04 0.04 Total deposits (mg) 17.3 14.2 15.5 7.4 18.2 12.9 15.7
36.6 49.3 33.8 47.4 TEOST 33C
The results of the TEOST 33C generally demonstrate the benefit of
increasing dispersant and detergent levels while decreasing
antioxidant levels, particularly aminic antioxidant, for reducing
deposit formation in turbochargers in non-ether containing
compositions, in line with expectations (for instance, compare
results for compositions F and G or compare composition D with A-C
and E to G). In addition, the results demonstrate that the presence
of the at least one polymethacrylate compound, alone or also in
combination with the at least one molybdenum compound, is tolerated
better by the ether composition than the corresponding non-ether
composition (compare results of compositions H and J as well as I
and K) in the TEOST 33C test. This is surprising when the DSC
oxidation onset stability of the ether base stock is lower than
that of the conventional Group III base stock as demonstrated in
Example 1 (on the basis of which poorer TEOST 33C performance would
be expected). This is particularly advantageous since the ether
composition exhibits a lower viscosity profile than the
corresponding non-ether composition whilst exhibiting greater high
temperature stability in the TEOST 33C test than the corresponding
non-ether composition. This means that a benefit may be seen in
terms of fuel economy through the use of the ether composition of
the invention in comparison to a conventional Group III base oil
composition containing no ether base stock, yet without any
accompanying increase in turbocharger deposits and piston
scuffing.
Example 5
Hot Liquid Process Simulator (HLPS) Testing
[0357] Blended compositions comprising Guerbet-derived base stock
(GE3) and/or a
[0358] Group III base stock (Yubase 4) together with varying
amounts of sulphonate (400BN), neutral sulphonate, and phenate
(150BN) detergents were subjected to HLPS testing. The HLPS testing
corresponds to a hot-tube test in which all oil compositions were
subjected to the same heating stress, for the same period of time.
HLPS testing is used as a means for characterising the propensity
of an oil to create deposits in a hotregion of the engine by
simulating pressurized oil lines. Results of the HLPS testing in
the form of Maximum Deposit Thickness ("MDT") (nm), which
corresponds to the maximum thickness of deposit measured along the
HLPS tube, and total deposit volume (cm.sup.3.times.10.sup.-17) are
provided in Table 10 (compositional data shown in % by weight).
TABLE-US-00010 TABLE 10 Lubricant Composition a b c d e f g h i j k
l Yubase 4 100 99.35 97.9 98.57 99.14 99.403 50 49.35 47.9 48.57
49.14 49.403 GE3 ether 50 50 50 50 50 50 Sulphonate (400BN) 0.65
1.43 0.65 1.43 Sulphonate (neutral) 0.86 0.86 Phenate 2.1 0.597 2.1
0.597 HLPS deposit vol. 4.08 5.97 6.76 No result 5.13 2.95 4.28
3.90 2.73 3.98 3.86 3.42 (cm.sup.3, .times. 10.sup.-17) MDT nm 252
178 249 232 98 192 249 110 250 199 75
[0359] The results of the HLPS tests demonstrate that, for a given
TBN value, the ether based compositions comprising a phenate
detergent exhibit significantly lower deposit levels than the
corresponding non-ether based compositions. The ether compositions
comprising a typical level of neutral sulphonate also perform
markedly better than the corresponding non-ether based
compositions. The results shown in Table 10 are also shown in the
graphs of FIGS. 1 and 2 which show Maximum Deposit Thickness and
deposit volume for each of the compositions tested respectively.
These data show the advantages that may be derived by employing
particular detergents, for instance phenate or neutral sulphonate,
in an ether-based lubricant composition for reducing the propensity
for deposit formation. This means that other lubricant additives
that are known to increase deposits, for example antioxidants, may
be used at higher levels without resulting in unacceptable level of
deposit formation.
[0360] The dimensions and values disclosed herein are not to be
understood as being strictly limited to the exact numerical values
recited. Instead, unless otherwise specified, each such dimension
is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension
disclosed as "40 mm" is intended to mean "about 40 mm."
[0361] Every document cited herein, including any cross referenced
or related patent or application, is hereby incorporated herein by
reference in its entirety unless expressly excluded or otherwise
limited. The citation of any document is not an admission that it
is prior art with respect to any invention disclosed or claimed
herein or that it alone, or in any combination with any other
reference or references, teaches, suggests or discloses any such
invention. Further, to the extent that any meaning or definition of
a term in this document conflicts with any meaning or definition of
the same term in a document incorporated by reference, the meaning
or definition assigned to that term in this document shall
govern.
[0362] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope and
spirit of this invention.
* * * * *