U.S. patent application number 10/943375 was filed with the patent office on 2007-08-16 for viscosity modifiers for lubricant compositions.
Invention is credited to Akhilesh Duggal, Paul G. Griffin, Peter Growcott, Yoon Soo Song, Sanjay Srinivasan, Joseph Stephen Strukl.
Application Number | 20070191242 10/943375 |
Document ID | / |
Family ID | 35601807 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070191242 |
Kind Code |
A1 |
Srinivasan; Sanjay ; et
al. |
August 16, 2007 |
Viscosity modifiers for lubricant compositions
Abstract
A lubricant composition method of using the lubricant
composition. The lubricant composition contains a base oil of
lubricating viscosity and from about 5 to about 30 percent by
weight of an additive comprising a shear stable olefin copolymer
derived from a copolymer having a number average molecular weight
ranging from about 50,000 to about 250,000. The shear stable olefin
copolymer has a shear stability index of less than about 40, a
polydispersity of not more than about 1.5, and a thickening
efficiency of greater than about 1.8, and provides viscosity index
improving properties to the lubricant composition.
Inventors: |
Srinivasan; Sanjay;
(Midlothian, VA) ; Song; Yoon Soo; (Richmond,
VA) ; Strukl; Joseph Stephen; (Midlothian, VA)
; Growcott; Peter; (Hampshire, GB) ; Griffin; Paul
G.; (Glen Allen, VA) ; Duggal; Akhilesh;
(Midlothian, VA) |
Correspondence
Address: |
NEW MARKET SERVICES CORPORATION;(FORMERLY ETHYL CORPORATION)
330 SOUTH 4TH STREET
RICHMOND
VA
23219
US
|
Family ID: |
35601807 |
Appl. No.: |
10/943375 |
Filed: |
September 17, 2004 |
Current U.S.
Class: |
508/591 ; 585/10;
585/12 |
Current CPC
Class: |
C10M 2205/06 20130101;
C10M 2205/00 20130101; C10N 2020/019 20200501; C10M 2205/022
20130101; C10N 2020/04 20130101; C10N 2040/255 20200501; C10N
2040/252 20200501; C10M 2205/024 20130101; C10N 2070/02 20200501;
C10M 171/02 20130101; C10N 2030/68 20200501; C10N 2060/09 20200501;
C10N 2020/00 20130101; C10M 2205/028 20130101; C10M 2205/08
20130101; C10N 2020/073 20200501; C10N 2060/00 20130101; C10M
171/04 20130101; C10N 2040/042 20200501; C10M 2205/04 20130101 |
Class at
Publication: |
508/591 ;
585/010; 585/012 |
International
Class: |
C10M 143/00 20060101
C10M143/00 |
Claims
1. A lubricated surface comprising a thin film coating of a
lubricant composition containing a base oil of lubricating
viscosity and from about 5 to about 30 percent by weight of an
additive comprising a shear stable olefin copolymer derived from a
copolymer having a number average molecular weight ranging from
about 50,000 to about 250,000, wherein the shear stable olefin
copolymer has a shear stability index of less than about 40, a
polydispersity of not more than about 1.5, and a thickening
efficiency of greater than about 1.8, and wherein the amount of
additive in the lubricant composition is based on a total weight of
the lubricant composition.
2. The lubricated surface of claim 1, wherein the lubricated
surface comprises an engine drive train.
3. The lubricated surface of claim 1, wherein the lubricated
surface comprises an internal surface or component of an internal
combustion engine.
4. The lubricated surface of claim 1, wherein the lubricated
surface comprises an internal surface or component of a compression
ignition engine.
5. The lubricated surface of claim 1, wherein the shear stable
copolymer is derived from the group consisting of
ethylene-propylene monomers, ethylene-propylene-diene monomers,
styrene-isoprene, and styrene-neoprene monomers.
6. The lubricated surface of claim 1, wherein the shear stable
copolymer is derived from a relatively low temperature, homogenized
copolymer.
7. The lubricated surface of claim 1, wherein each monomeric unit
of the shear stable copolymer contains from about 2 to about 10
carbon atoms.
8. The lubricated surface of claim 1, wherein the shear stable
copolymer comprises an amorphous ethylene containing copolymer
having an ethylene content below about 70 percent by weight of the
copolymer.
9. A motor vehicle comprising the lubricated surface of claim
1.
10. A vehicle having moving parts and containing a lubricant for
lubricating the moving parts, the lubricant comprising an oil of
lubricating viscosity and from about 5 to about 30 percent by
weight of an additive comprising a shear stable olefin copolymer
derived from a copolymer having a number average molecular weight
ranging from about 50,000 to about 250,000, wherein the shear
stable olefin copolymer has a shear stability index of less than
about 40, a polydispersity of not more than about 1.5, and a
thickening efficiency of greater than about 1.8, and wherein the
amount of additive in the lubricant is based on a total weight of
the lubricant.
11. The vehicle of claim 10, wherein the shear stable copolymer is
derived from the group consisting of ethylene-propylene monomers,
ethylene-propylene-diene monomers, styrene-isoprene, and
styrene-neoprene monomers.
12. The vehicle of claim 10, wherein the shear stable copolymer
comprises an olefin copolymer mechanically sheared in a
homogenizer.
13. The vehicle of claim 10, wherein the moving parts comprise a
heavy duty diesel engine including exhaust gas recirculation and a
lubricating system for the engine.
14. The vehicle of claim 10, wherein each monomeric unit of the
shear stable copolymer contains from about 2 to about 10 carbon
atoms.
15. The vehicle of claim 10, wherein the shear stable copolymer
comprises an amorphous ethylene containing copolymer having an
ethylene content below about 70 percent by weight of the
copolymer.
16. A fully formulated lubricant composition comprising a base oil
component of lubricating viscosity and from about 5 to about 30
percent by weight of an additive comprising a shear stable olefin
copolymer derived from a copolymer having a number average
molecular weight ranging from about 50,000 to about 250,000,
wherein the shear stable olefin copolymer has a shear stability
index of less than about 40, a polydispersity of not more than
about 1.5, and a thickening efficiency of greater than about 1.8,
and wherein the amount of additive in the lubricant composition is
based on a total amount of lubricant composition.
17. The lubricant composition of claim 16, wherein the shear stable
copolymer is derived from the group consisting of
ethylene-propylene monomers, ethylene-propylene-diene monomers,
styrene-isoprene, and styrene-neoprene monomers.
18. The lubricant composition of claim 16, wherein the shear stable
copolymer comprises an olefin copolymer mechanically sheared in a
homogenizer.
19. The lubricant composition of claim 16, wherein each monomeric
unit of the shear stable copolymer contains from about 2 to about
10 carbon atoms.
20. The lubricant composition of claim 16, wherein the shear stable
copolymer comprises an amorphous ethylene containing copolymer
having an ethylene content below about 70 percent by weight.
21. A method for improving the viscosity index of a lubricant
composition comprising mixing with the lubricant composition from
about 5 to about 30 percent by weight of an additive comprising a
shear stable olefin copolymer derived from a copolymer having a
number average molecular weight ranging from about 50,000 to about
250,000, wherein the shear stable olefin copolymer has a shear
stability index of less than about 40, a polydispersity of not more
than about 1.5, and a thickening efficiency of greater than about
1.8, and wherein the amount of shear stable olefin copolymer in the
lubricant composition is based on a total weight of the lubricant
composition.
22. The method of claim 21, wherein the lubricant composition
comprises a multi-viscosity lubricating oil.
23. The method of claim 21, wherein the wherein the shear stable
copolymer is derived from the group consisting of
ethylene-propylene monomers, ethylene-propylene-diene monomers,
styrene-isoprene, and styrene-neoprene monomers.
24. The method of claim 21, wherein the shear stable copolymer
comprises an olefin copolymer mechanically sheared in a
homogenizer.
25. The method of claim 21, wherein each monomeric unit of the
shear stable copolymer contains from about 2 to about 10 carbon
atoms.
26. The method of claim 21, wherein the shear stable copolymer
comprises an amorphous ethylene containing copolymer having an
ethylene content below about 70 percent by weight of the
copolymer.
27. A lubricant additive concentrate comprising a diluent or
carrier oil and from about 5 to about 90 percent by weight of an
additive comprising a shear stable olefin copolymer derived from a
copolymer having a number average molecular weight ranging from
about 50,000 to about 250,000, wherein the shear stable olefin
copolymer has a shear stability index of less than about 40, a
polydispersity of not more than about 1.5, and a thickening
efficiency of greater than about 1.8, and wherein the amount of
shear stable olefin copolymer in the lubricant composition is based
on a total weight of the additive concentrate.
28. The additive concentrate of claim 27, wherein the wherein the
shear stable copolymer is derived from the group consisting of
ethylene-propylene monomers, ethylene-propylene-diene monomers,
styrene-isoprene, and styrene-neoprene monomers.
29. The additive concentrate of claim 27, wherein the shear stable
copolymer comprises an olefin copolymer mechanically sheared in a
homogenizer.
30. The additive concentrate of claim 27, wherein each monomeric
unit of the shear stable copolymer contains from about 2 to about
10 carbon atoms.
31. The additive concentrate of claim 27, wherein the shear stable
copolymer comprises an amorphous ethylene containing copolymer
having an ethylene content below about 70 percent by weight of the
copolymer.
32. A lubricant composition comprising a base oil and the additive
concentrate of claim 27.
33. A method of lubricating moving parts of a vehicle, the method
comprising using as a lubricating oil for one or more moving parts
of the vehicle a lubricant composition containing a base oil and a
lubricant additive, the lubricant additive comprising a diluent or
carrier oil and an amount of shear stable olefin copolymer derived
from a copolymer having a number average molecular weight ranging
from about 50,000 to about 250,000 sufficient to provide from about
5 to about 30 weight percent of the shear stable olefin copolymer
in the lubricant composition, wherein the shear stable olefin
copolymer has a shear stability index of less than about 40, a
polydispersity of not more than about 1.5, and a thickening
efficiency of greater than about 1.8, and wherein the amount of
shear stable olefin copolymer in the lubricant composition is based
on a total weight of the lubricant composition.
34. The method of claim 33, wherein the wherein the shear stable
copolymer is derived from the group consisting of
ethylene-propylene monomers, ethylene-propylene-diene monomers,
styrene-isoprene, and styrene-neoprene monomers.
35. The method of claim 33, wherein the shear stable copolymer
comprises an olefin copolymer mechanically sheared in a
homogenizer.
36. The method of claim 33, wherein each monomeric unit of the
shear stable copolymer contains from about 2 to about 10 carbon
atoms.
37. The method of claim 33, wherein the shear stable copolymer
comprises an amorphous ethylene containing copolymer having an
ethylene content below about 70 percent by weight of the
copolymer.
38. The method of claim 33 wherein the vehicle includes a diesel
engine and wherein the moving parts include moving parts of the
engine.
39. The method of claim 33 wherein the vehicle includes a marine
vehicle having an engine, and wherein the moving parts include
moving parts of the engine.
40. The method of claim 33, wherein the vehicle includes a spark
ignition engine, and wherein the moving parts include moving parts
of the engine.
41. The method of claim 33, wherein the vehicle includes a drive
train, and wherein the moving parts include moving parts of the
drive train.
42. The method of claim 33 wherein the vehicle includes an internal
combustion engine having a crankcase and wherein the lubricant
composition comprises a crankcase oil present in the crankcase of
the vehicle.
43. The method of claim 33 wherein the lubricant composition
comprises a drive train lubricant present in an automotive drive
train of the vehicle.
44. A method of lubricating moving parts comprising contacting the
moving parts with a lubricant composition containing a lubricant
additive, the lubricant additive comprising a diluent or carrier
oil and from about 5 to about 95 percent by weight of a shear
stable olefin copolymer derived from a copolymer having a number
average molecular weight ranging from about 50,000 to about
250,000, wherein the shear stable olefin copolymer has a shear
stability index of less than about 40, a polydispersity of not more
than about 1.5, and a thickening efficiency of greater than about
1.8, wherein the lubricant composition contains from about 5 to
about 30 percent by weight of the additive based on a total weight
of the lubricant composition.
45. The method of claim 44 wherein the moving parts comprise moving
parts of a vehicle.
46. The method of claim 44 wherein the vehicle includes a marine
vehicle having an engine, and wherein the moving parts include
moving parts of the engine.
47. The method of claim 44 wherein the moving parts include an
internal combustion engine having a crankcase and wherein the
lubricant composition comprises a crankcase oil present in the
crankcase of the vehicle.
48. The method of claim 44 wherein the lubricant composition
comprises a drive train lubricant present in an automotive drive
train of the vehicle.
Description
TECHNICAL FIELD
[0001] The following disclosure is directed to lubricants,
lubricant compositions and additives, lubricated parts and engines,
and methods for lubricating moving parts.
BACKGROUND
[0002] Lubricating oils used in gasoline and diesel crankcases
include a natural and/or synthetic basestock and one or more
additives to impart desired characteristics to the lubricant. Such
additives typically include ashless dispersant, metal detergent,
antioxidant and antiwear components, which may be combined in a
package, sometimes referred to as a detergent inhibitor (or DI)
package.
[0003] Multigrade oils usually also contain one or more viscosity
modifiers which are relatively long chain polymers. Such polymers
may be functionalized to provide other properties when they are
known as multifunctional viscosity modifiers, but primarily act to
improve the viscosity characteristics of the oil over a desired
operating temperature range. The viscosity modifier acts to
increase viscosity at high temperature to provide more protection
to the engine at high speeds, without unduly increasing viscosity
at low temperatures which would otherwise make starting a cold
engine difficult. High temperature performance is usually measured
in terms of the kinematic viscosity (kV) at 100.degree. C. (ASTM
D445), while low temperature performance is measured in terms of
cold cranking simulator (CCS) viscosity (ASTM D5293, which is a
revision of ASTM D2602)), mini-rotary viscometer (MRV; ASTM D4684),
or scanning brookfield or gel index (ASTM D5133).
[0004] Viscosity grades are defined by the SAE Classification
system (SAE J300) according to the foregoing temperature
measurements. Multigrade oils meet the requirements of both low
temperature and high temperature performance and are thus
referenced to both the relevant grades.
[0005] Shear stability is a measure of the ability of an oil to
resist permanent viscosity loss under high shear--the more shear
stable an oil the smaller the viscosity loss when subjected to
shear. Polymeric viscosity modifiers, which make a significant
contribution to kV 100.degree. C., are not entirely shear stable.
Such polymeric viscosity modifiers are characterized by a shear
stability index (SSI).
[0006] An oil or additive that exhibits relatively high shear
stability will have an SSI that is relatively low. Typically,
higher molecular weight polymers used in lubricating oil
applications have poor shear stability (i.e., high SSI). However,
viscosity modifiers with relatively low SSI require higher treat
rates due to their relatively lower molecular weights and therefore
lead to an increase in total formulation costs. Multigrade oils
often have poor shear stability unless they use expensive viscosity
modifiers having low SSI. Poor shear stability requires the oils to
be blended to a higher initial kV 100.degree. C. which may result
in poor fuel economy. Accordingly, there is a need for improved
viscosity modifiers which are relatively shear stable and more cost
effective to use in lubricant composition.
SUMMARY OF THE EMBODIMENTS
[0007] In one embodiment herein is presented a lubricated surface.
The lubricated surface includes a thin film coating of a lubricant
composition containing a base oil of lubricating viscosity and from
about 5 to about 30 percent by weight of an additive comprising a
shear stable olefin copolymer derived from a copolymer having a
number average molecular weight ranging from about 50,000 to about
250,000. The shear stable olefin copolymer has a shear stability
index of less than about 40, a polydispersity of not more than
about 1.5, and a thickening efficiency of greater than about
1.8.
[0008] In another embodiment, there is provided a vehicle having
moving parts and containing a lubricant for lubricating the moving
parts. The lubricant contains an oil of lubricating viscosity and
from about 5 to about 30 percent by weight of an additive
comprising a shear stable olefin copolymer derived from a copolymer
having a number average molecular weight ranging from about 50,000
to about 250,000. The shear stable olefin copolymer has a shear
stability index of less than about 40, a polydispersity of not more
than about 1.5, and a thickening efficiency of greater than about
1.8.
[0009] In yet another embodiment there is provided a method of
lubricating moving parts. The method includes contacting the moving
parts with a lubricant composition containing a lubricant additive.
The lubricant additive includes a diluent or carrier oil and from
about 5 to about 95 percent by weight of a shear stable olefin
copolymer derived from a copolymer having a number average
molecular weight ranging from about 50,000 to about 250,000. The
shear stable olefin copolymer has a shear stability index of less
than about 40, a polydispersity of not more than about 1.5, and a
thickening efficiency of greater than about 1.8. The lubricant
composition contains from about 5 to about 30 percent by weight of
the additive based on a total weight of the lubricant
composition.
[0010] A further embodiment of the disclosure provides a method for
improving the viscosity index of a lubricant composition. The
method includes mixing with the lubricant composition from about 5
to about 30 percent by weight of an additive comprising a shear
stable olefin copolymer derived from a copolymer having a number
average molecular weight ranging from about 50,000 to about
250,000. The shear stable olefin copolymer has a shear stability
index of less than about 40, a polydispersity of not more than
about 1.5, and a thickening efficiency of greater than about
1.8.
[0011] An advantage of the shear stable copolymer as described
herein is that the polymer exhibits improved thickening efficient
at a lower polymer loading. Another advantage of the shear stable
copolymer is that it may be made using an amorphous lower ethylene
containing copolymer, e.g., a copolymer having an ethylene content
in the range of from about 40% to about 55% by weight. In addition
to the shear stable olefin copolymers, the disclosure may also be
applicable to shear stable star polymers based on styrene-isoprene
chemistry.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Further features and advantages of the embodiments will
become apparent by reference to the detailed description of
preferred embodiments when considered in conjunction with the
following drawings, in which like reference numbers denote like
elements throughout the several views, and wherein:
[0013] FIG. 1 is a shear stability index profile of a mechanically
sheared olefin copolymer according to the disclosure;
[0014] FIG. 2 is a polydispersity profile for a mechanically
sheared olefin copolymer according to the disclosure;
[0015] FIG. 3 is a graphical representation of a viscosity profile
for a mechanically sheared olefin copolymer according to the
disclosure;
[0016] FIG. 4 is a graphical representation of an olefin copolymer
according to the disclosure in a process oil illustrating a change
in viscosity during mechanical shearing compared to conventional
olefin copolymers prepared under a high temperature extruder
shearing and direct finishing process; and
[0017] FIG. 5 is a thickening efficiency profile for a mechanically
sheared olefin copolymer according to the disclosure compared to a
thickening efficiency of conventional olefin copolymers prepared
under a high temperature extruder shearing and direct finishing
process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] As used herein, the term "hydrocarbyl substituent" or
"hydrocarbyl group" is used in its ordinary sense, which is
well-known to those skilled in the art. Specifically, it refers to
a group having a carbon atom directly attached to the remainder of
the molecule and having a predominantly hydrocarbon character.
Examples of hydrocarbyl groups include:
[0019] (1) hydrocarbon substituents, that is, aliphatic (e.g.,
alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl)
substituents, and aromatic-, aliphatic-, and alicyclic-substituted
aromatic substituents, as well as cyclic substituents wherein the
ring is completed through another portion of the molecule (e.g.,
two substituents together form an alicyclic radical);
[0020] (2) substituted hydrocarbon substituents, that is,
substituents containing non-hydrocarbon groups which, in the
context of the description herein, do not alter the predominantly
hydrocarbon substituent (e.g., halo (especially chloro and fluoro),
hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and
sulfoxy);
[0021] (3) hetero-substituents, that is, substituents which, while
having a predominantly hydrocarbon character, in the context of
this description, contain other than carbon in a ring or chain
otherwise composed of carbon atoms. Hetero-atoms include sulfur,
oxygen, nitrogen, and encompass substituents such as pyridyl,
furyl, thienyl and imidazolyl. In general, no more than two,
preferably no more than one, non-hydrocarbon substituent will be
present for every ten carbon atoms in the hydrocarbyl group;
typically, there will be no non-hydrocarbon substituents in the
hydrocarbyl group.
[0022] In all of the embodiments of the disclosure, a particular
lubricant component or additive is provided. The additive is
referred to generally as a multi-functional viscosity index
modifier. Specifically, the lubricant additive includes a shear
stable olefin copolymer derived from a copolymer having a number
average molecular weight ranging from about 15,000 to about 500,000
or more. The shear stable olefin copolymer may have a shear
stability index of less than about 40 and a polydispersity of less
than or equal to about 1.5. As described herein, shear stable
olefin copolymer is dissolved in a suitable solvent such as Solvent
Neutral 150 to provide the additive component.
[0023] A wide variety of copolymers and terpolymers may be used as
starting materials for making the shear stable copolymer. The
copolymers are referred to generally as olefin copolymers, however,
the disclosed embodiments may also be applicable to copolymers
derived from styrene-isoprene. The copolymers typically have number
average molecular weights of from about 15,000 to about 500,000;
preferably about 20,000 to about 300,000, and more preferably from
about 100,000 to about 200,000. The shear stable copolymers
generally have a narrow range of molecular weight, as determined by
the ratio of weight-average molecular weight (Mw) to number-average
molecular weight (Mn), referred to hereinafter as "polydispersity."
Suitable olefin copolymers have a polydispersity of less than 10,
preferably less than 7, and more preferably 4 or less. The (Mn) and
(Mw/Mn) of the copolymers are measured by the well known techniques
of vapor phase osmometry (VPO), membrane osmometry and gel
permeation chromatography. The shear stable copolymers derived from
the olefin copolymers may have a polydispersity of less than or
equal to about 1.5.
[0024] In general, shear stable copolymers having a narrow range of
molecular weight may be obtained by relatively low temperature
mechanical shearing. Conventional copolymer shearing is conducted
at temperatures above about 100.degree. C. (212.degree. F.) in an
extrusion shearing process. By contrast, shearing of the copolymers
according to the disclosure is conducted at a temperature below
about 100.degree. C. (212.degree. F.), typically from about
35.degree. C. (95.degree. F.) to about 85.degree. C. (135.degree.
F.) in a homogenizer. Accordingly, the term "relatively low
temperature" means a temperature below a temperature used in a
conventional extrusion shearing process for shearing
copolymers.
[0025] The homogenizer used in the process may be any type capable
of developing a pressure in excess of 500 pounds per square inch
wherein the product is subjected to high shearing action upon
release of said pressure. Typical of the homogenizers which may be
used are those of the type conventionally used in the
homogenization of dairy products and in the preparation of
emulsions utilized as polishing compounds, cosmetics,
pharmaceuticals and liquid soaps. The copolymers may be sheared
using multiple passes through the homogenizer, for example from
about 2 to about 10 passes through the homogenizer.
[0026] The olefin copolymer sheared in the homogenizer may be
prepared from ethylene and ethylenically unsaturated hydrocarbons
including cyclic, alicyclic and acyclic, compounds containing from
3 to 28 carbons, e.g. 2 to 18 carbons. The ethylene copolymers may
contain from about 15 to about 90 wt. % ethylene, preferably, from
about 30 to about 80 wt. % of ethylene, and most preferably less
than about 70 wt. % ethylene. The copolymers may also contain from
about 10 to about 85 wt. %, preferably 20 to 70 wt. % of one or
more C.sub.3 to C.sub.28, preferably C.sub.3 to C.sub.18 more
preferably C.sub.3 to C.sub.10, unsaturated hydrocarbons,
preferably alpha olefins.
[0027] Copolymers of ethylene and propylene are most preferred.
However, other alpha-olefins suitable in place of propylene to form
the copolymer, or to be used in combination with ethylene and
propylene, to form a terpolymer, tetrapolymer, etc., include, but
are not limited to, 1-pentene, 1-hexene, 1-heptene, 1-octene,
1-nonene, 1-decene, etc.; also branched chain alpha-olefins, such
as 4-methyl-1-pentene, 4-methyl-1-hexene, 5-methylpentene-1,
4,4-dimethyl-1-pentene, and 6-methylheptene-1, etc., and mixtures
thereof.
[0028] The term copolymer as used herein, unless otherwise
indicated, includes terpolymers, tetrapolymers, interpolymers,
etc., of ethylene and C.sub.3-28 alpha-olefin and/or a
non-conjugated diolefin or mixtures of such diolefins which may
also be used. Such materials may contain minor amounts of other
olefinic monomers so long as the basic characteristics of the
olefin copolymers are not materially changed. The amount of the
non-conjugated diolefin will generally range from about 0.5 to 20
mole percent, preferably about 1 to about 7 mole percent, based on
the total amount of ethylene and alpha-olefin present.
[0029] Representative examples of non-conjugated dienes that may be
included in a terpolymer include straight chain acyclic dienes such
as 1,4-hexadiene; 1,5-heptadiene; 1,6-octadiene; branched chain
acyclic dienes such as 5-methyl-1,4-hexadiene; 3,7-dimethyl
1,6-octadiene; 3,7-dimethyl-1,7-octadiene; and the mixed isomers of
dihydro-myrcene and dihydro-cymene; single ring alicyclic dienes
such as 1,4-cyclohexadiene; 1,5-cyclooctadiene;
1,5-cyclododecadiene; 4-vinylcyclohexene; 1-allyl-4-isopropylidene
cyclohexane; 3-allyl-cyclopentene; 4-allyl-cyclohexene and
1-isopropenyl-4-(4-butenyl) cyclohexane; multi-single ring
alicyclic dienes such as 4,4-dicyclopentenyl and 4,4-dicyclohexenyl
dienes; multi-ring alicyclic fused and bridged ring dienes such as
tetrahydroindene; methyl tetrahydroindene; dicyclopentadiene;
bicyclo (2.2.1) hepta-2,5-diene; alkyl, alkenyl, alkylidene,
cycloalkenyl and cycloalkylidene norbornenes such as: ethyl
norbornene; 5-methylene-6-methyl-2-norbornene;
5-methylene-6,6-dimethyl-2-norbornene; 5-propenyl-2-norbornene;
5-(3-cyclopentenyl)2-norbomene and 5-cyclohexylidene-2-norbornene;
norbornadiene; etc.
[0030] Specifically, the shear stable olefin copolymer may be
derived from the polymerization of ethylene-propylene monomers,
ethylene-propylene-diene monomers, styrene-neoprene monomers,
styrene-isoprene monomers, and the like.
[0031] Ethylene-propylene or higher alpha-olefin copolymers may
consist of from about 15 to about 80 weight percent ethylene and
from about 85 to about 20 weight percent C.sub.3 to C.sub.23
alpha-olefin with the preferred weight ratios being from about 35
to about 75 weight percent ethylene and from about 65 to about 25
weight percent of a C.sub.3 to C.sub.23 alpha-olefin, with the more
preferred proportions being from about 50 to less than about 70
weight percent ethylene and about 50 to about 30 weight percent
C.sub.3 to C.sub.23 alpha-olefin, and the most preferred
proportions being from about 55 to about 65 weight percent ethylene
and from about 45 to about 35 weight percent C.sub.3 to C.sub.23
alpha-olefin.
[0032] Also included among the olefin copolymers for making the
shear stable olefin copolymers as described herein are those olefin
copolymers which have been functionalized by means of a free
radical graft reaction or a graft polymerization reaction. Such
grafted copolymers are themselves well known to those skilled in
the art.
[0033] Graft monomers for functionalizing olefin copolymers are the
derivatives of olefinically unsaturated carboxylic monomers such
as, maleic anhydride, acrylic or methacrylic acid, or their esters,
graft monomers which are likewise known to those skilled in the
art. Typically, acrylic and methacrylic acid derivative contain 4
to 16 carbon atoms. Particularly preferred among the group of
acrylic or methacrylic graft monomers are glycidyl methacrylate,
methylacrylate, methylmethacrylate, ethylmethacrylate and
aminopropylmethacrylate, and acrylamide.
[0034] Another group of graft monomers which can be used to
functionalize the olefin copolymers are vinyl amines containing 2
to 25 carbon atoms, and preferably heterocyclic vinyl amines. Such
amines are themselves known as functionalizing graft monomers and
include allylamines, N-vinylpyridines, N-vinylpyrrolidones, vinyl
lactams, vinylcarbazoles, vinylimidazoles and vinylthiazoles as
represented by 2-vinylpyridine, N-vinylpyrrolidone, vinyl
caprolactam, 1-vinylimidazole, allylamine, 4-methyl-5-vinylthiazole
and 9-vinylcarbazole. Such graft monomers are described in detail
in U.S. Pat. No. 4,340,689, the disclosure of which is incorporated
herein by reference.
[0035] As it will be appreciated by those skilled in the art, other
vinyl monomers described in the prior art as suitable for
functionalizing olefin copolymers may likewise be used in the
practice of the present invention. Examples of such further vinyl
compounds are the vinyl silanes and vinyl-benzyl halides as
represented by vinyltrimethoxysilane, vinyldiethychlorosilane,
vinylbenzylchloride and the like. Further descriptions of suitable
silane graft monomers are described in U.S. Pat. No. 4,340,689, the
disclosure of which is incorporated herein by reference.
[0036] The shear stable olefin copolymer of the embodiments
described herein is advantageously incorporated into lubricating
compositions. The shear stable olefin copolymer may be added
directly to the lubricating oil composition. In one embodiment,
however, the copolymer is diluted with a substantially inert,
normally liquid organic diluent such as mineral oil, synthetic oil
(e.g., ester of dicarboxylic acid), naptha, alkylated (e.g.,
C.sub.10--C13 alkyl) benzene, toluene or xylene to form an additive
concentrate. The shear stable olefin copolymer concentrate usually
contain from about 0% to about 99% by weight diluent oil.
[0037] In the preparation of lubricating oil formulations it is
common practice to introduce the additives in the form of 1 to 99
wt. % active ingredient concentrates in hydrocarbon oil, e.g.
mineral lubricating oil, or other suitable solvent. Usually these
concentrates may be added with 0.05 to 10 parts by weight of
lubricating oil per part by weight of the additive package in
forming finished lubricants, e.g. crankcase motor oils. The purpose
of concentrates, of course, is to make the handling of the various
materials less difficult and awkward as well as to facilitate
solution or dispersion in the final blend.
[0038] Lubricant compositions made with the shear stable olefin
copolymers described above are used in a wide variety of
applications. For compression ignition engines and spark ignition
engines, it is preferred that the lubricant compositions meet or
exceed published GF-4 or API-CI-4 standards. Lubricant compositions
according to the foregoing GF-4 or API-CI-4 standards include a
base oil and an oil additive package to provide a fully formulated
lubricant. The base oil for lubricants according to the disclosure
is an oil of lubricating viscosity selected from natural
lubricating oils, synthetic lubricating oils and mixtures thereof.
Such base oils include those conventionally employed as crankcase
lubricating oils for spark-ignited and compression-ignited internal
combustion engines, such as automobile and truck engines, marine
and railroad diesel engines, and the like.
[0039] Natural oils include animal oils and vegetable oils (e.g.,
castor oil, lard oil), liquid petroleum oils and hydrorefined,
solvent-treated or acid-treated mineral lubricating oils of the
paraffinic, naphthenic and mixed paraffinic-naphthenic types. Oils
of lubricating viscosity derived from coal or shale are also useful
base oils. The synthetic lubricating oils used in this invention
include one of any number of commonly used synthetic hydrocarbon
oils, which include, but are not limited to, poly-alpha-olefins,
alkylated aromatics, alkylene oxide polymers, interpolymers,
copolymers and derivatives thereof here the terminal hydroxyl
groups have been modified by esterification, etherification etc,
esters of dicarboxylic acids and silicon-based oils.
[0040] Fully formulated lubricants conventionally contain an
additive package, referred to herein as a dispersant/inhibitor
package or DI package, that will supply the characteristics that
are required in the formulations. Suitable DI packages are
described for example in U.S. Pat. Nos. 5,204,012 and 6,034,040 for
example. Among the types of additives included in the additive
package are detergents, dispersants, friction modifiers, seal swell
agents, antioxidants, foam inhibitors, lubricity agents, rust
inhibitors, corrosion inhibitors, demulsifiers, viscosity index
improvers, and the like. Several of these components are well known
to those skilled in the art and are preferably used in conventional
amounts with the additives and compositions described herein.
[0041] For example, ashless dispersants include an oil soluble
polymeric hydrocarbon backbone having functional groups that are
capable of associating with particles to be dispersed. Typically,
the dispersants comprise amine, alcohol, amide, or ester polar
moieties attached to the polymer backbone often via a bridging
group. The ashless dispersants may be, for example, selected from
oil soluble salts, esters, amino-esters, amides, imides, and
oxazolines of long chain hydrocarbon substituted mono and
dicarboxylic acids or their anhydrides; thiocarboxylate derivatives
of long chain hydrocarbons; long chain aliphatic hydrocarbons
having a polyamine attached directly thereto; and Mannich
condensation products formed by condensing a long chain substituted
phenol with formaldehyde and a polyalkylene polyamine.
[0042] Oxidation inhibitors or antioxidants reduce the tendency of
base stocks to deteriorate in service which deterioration can be
evidenced by the products of oxidation such as sludge and
varnish-like deposits on the metal surfaces and by viscosity
growth. Such oxidation inhibitors include hindered phenols,
alkaline earth metal salts of alkylphenol thioesters having
preferably C.sub.5 to C.sub.12 alkyl side chains, calcium
nonylphenol sulfide, ashless oil soluble phenates and sulfurized
phenates, phosphosulfurized or sulfurized hydrocarbons, phosphorus
esters, metal thiocarbamates and oil soluble copper compounds as
described in U.S. Pat. No. 4,867,890.
[0043] Rust inhibitors selected from the group consisting of
nonionic polyoxyalkylene polyols and esters thereof,
polyoxyalkylene phenols, and anionic alkyl sulfonic acids may be
used.
[0044] A small amount of a demulsifying component may be used. A
preferred demulsifying component is described in EP 330,522. It is
obtained by reacting an alkylene oxide with an adduct obtained by
reacting a bis-epoxide with a polyhydric alcohol. The demulsifier
should be used at a level not exceeding 0.1 mass % active
ingredient. A treat rate of 0.001 to 0.05 mass % active ingredient
is convenient.
[0045] Pour point depressants, otherwise known as lube oil flow
improvers, lower the minimum temperature at which the fluid will
flow or can be poured. Such additives are well known. Typical of
those additives which improve the low temperature fluidity of the
fluid are C.sub.8 to C.sub.18 dialkyl fumarate/vinyl acetate
copolymers, polyalkylmethacrylates and the like.
[0046] Foam control can be provided by many compounds including an
antifoamant of the polysiloxane type, for example, silicone oil or
polydimethyl siloxane.
[0047] Seal swell agents, as described, for example, in U.S. Pat.
Nos. 3,974,081 and 4,029,587, may also be used.
[0048] Each of the foregoing additives, when used, is used at a
functionally effective amount to impart the desired properties to
the lubricant. Thus, for example, if an additive is a corrosion
inhibitor, a functionally effective amount of this corrosion
inhibitor would be an amount sufficient to impart the desired
corrosion inhibition characteristics to the lubricant. Generally,
the concentration of each of these additives, when used, ranges up
to about 20% by weight based on the weight of the lubricating oil
composition, and in one embodiment from about 0.001% to about 20%
by weight, and in one embodiment about 0.01% to about 10% by weight
based on the weight of the lubricating oil composition.
EXAMPLE
[0049] Four fully formulated lubricant compositions were made and
the viscometric and shear strength properties of the compositions
were compared. Each of the lubricant compositions contained a
conventional DI package providing 11 percent by weight of the
lubricant composition. The DI package contained conventional
amounts of detergents, dispersants, antiwear additives, friction
modifiers, antifoam agents, and antioxidants. The formulations also
contained about 0.1 percent by weight pour point depressant, about
58 to 64 percent by weight 150 solvent neutral oil, about 12 to 18
percent by weight 600 solvent neutral oil. Samples 1-3 provide the
characteristics of commercially available olefin copolymers as
viscosity modifiers. Sample 4 provides the characteristics of a
shear stable olefin copolymer made according to the disclosure.
[0050] In the tables, the following abbreviations are used:
[0051] VII--viscosity index improver
[0052] KV--kinematic viscosity
[0053] CCS--cold cranking simulator
[0054] MRV--mini rotary viscometer--tests conducted according to
ASTM D4684
[0055] HTHS--high temperature high shear--tests conducted according
to ASTM D-4683, D-4781, and D-5481. TABLE-US-00001 TABLE 1 Sample #
1 2 3 4 Viscosity Grade 15W50 15W50 15W50 15W50 Components Wt. %
Wt. % Wt. % Wt. % HiTEC .RTM. 9386.sup.1 11.00 11.00 11.00 11.00
HiTEC .RTM. 672.sup.2 0.10 0.10 0.10 0.10 ESSO 150 solvent neutral
63.60 63.00 58.20 63.50 ESSO 600 solvent neutral 12.40 13.50 17.30
12.00 Viscosity Index Modifier HiTEC .RTM. 5748.sup.3 12.90 0.00
0.00 0.00 LUBRIZOL 7077.sup.4 0.00 12.40 0.00 0.00 PARATONE
8006.sup.5 0.00 0.00 13.40 0.00 Shear Stable ethylene/propylene
0.00 0.00 0.00 13.40 Copolymer (50 wt. % ethylene) Total 100.00
100.00 100.00 100.00
[0056] TABLE-US-00002 TABLE 2 Sample # Lubricant Properties 1 2 3 4
Polymer content in, VII 13.12 12.61 10.27 9.88 (weight %) Polymer
loading in 1.69 1.56 1.38 1.32 blend (grams) KV at 100.degree. C.
(cSt) 18.98 19.06 19.02 18.96 KV at 40.degree. C. (cSt) 144.80
146.2 144.4 146.6 Viscosity index 149 149 150 147 CCS at
-20.degree. C. (cP) 6776 6897 6653 6840 (7000 cP max.) MRV
TP-1@-25.degree. C., cP 44900 47300 0 40800 MRV Yield Stress <35
<35 <140 <35 Noack Volatility, % 11.4 10.6 10.1 10.4 HTHS
at 150.degree. C. (cP) 4.89 4.95 4.63 4.79 KV at 100.degree. C.
after 30 16.29 16.55 16.03 16.16 cycle Bosch shear KV at
100.degree. C. % vis- 14.17 13.14 15.72 14.77 cosity loss (15%
max.) Shear stability Index 23.60 20.60 24.20 24.90 (SSI, %)
.sup.1HiTEC .RTM. 9386 is a commercially available DI package
available from Afton Chemical Corporation of Richmond, Virginia
.sup.2HiTEC .RTM. 672 is a commercially available pour point
depressant available from Afton Chemical Corporation .sup.3HiTEC
.RTM. 5748 is a olefin copolymer made by an extrusion shearing
process and is available from Afton Chemical Corporation
.sup.4LUBRIZOL 7077 is an olefin copolymer having an ethylene
content of about 50 weight percent and is available from Lubrizol
Corporation of Wickliffe, Ohio. (The table results are from an
average of two batches of LUBRIZOL 7077) .sup.5PARATONE 8006 is an
olefin copolymer having an ethylene content of about 70 weight
percent and is available from Chevron Oronite Company LLC of
Houston, Texas.
[0057] As seen in the foregoing Tables 1 and 2, sample 4 provides a
highly efficient viscosity modifier. Compared with samples 1-3,
sample 4 had the lowest polymer loading in the lubricant
composition (1.32 versus 1.38 to 1.69 for samples 1-3).
[0058] Sample 4 also had the highest shear stability index (SSI)
and passed the MRV tests and CCS test, whereas, sample 3 failed the
MRV test and viscosity loss test. Overall, sample 4 exhibited
improved viscometric and shear strength properties over
commercially available ethylene-based olefin copolymer
products.
[0059] In order to make shear stable olefin copolymers according to
the disclosure, 10 parts by weight ethylene/propylene copolymer
having a number average molecular weight as determined by gas phase
chromatography (GPC) of 179,192 and a weight average molecular
weight of 332,930 was mixed with 90 parts by weight of process oil.
The oil and copolymer mixture was cycled through a GAULIN
homogenizer from 1 to 10 times to provide a shear stable olefin
copolymer having a polydispersity of less than 1.5.
[0060] Properties of the olefin copolymer after zero to ten passes
through the homogenizer are provided in the following table and
FIGS. 1-3. FIGS. 4-5 provide a visual comparison of the thickening
efficiency and kinematic viscosity of the olefin copolymer after
zero to ten passes with the same properties of HiTECO.RTM. 5748 and
LUBRIZOL 7077 (LZ 7077) (Samples 6 and 7, respectively). The
comparisons were conducted with one percent olefin copolymer in a
reference oil having a viscosity as indicated in the table. The
kinematic viscosity at 100.degree. C. of the samples was estimated
by thermogravimetric analysis (TGA) by dissolving one weight
percent of each sample in about a five centistokes reference oil
(FIG. 4). TABLE-US-00003 TABLE 3 Sample No. 1 2 3 4 5 6 7 No. of
passes through 0 4 6 8 10 -- -- Homogenizer KV at 100.degree. C.
(cSt) 5422 1685 1299 1176 1048 1010 1212 KV at 40.degree. C. (cSt)
78489 21084 17234 14878 13109 13290 15153 VI 385.9 332.8 321.0
309.3 303.4 295.4 313.0 % Crystallinity 2.47 2.32 2.63 2.79 2.59
2.30 2.68 TGA/N2 (wt. % 9.635 9.638 9.668 9.568 9.627 12.97 12.80
Polymer) Wt. % process oil 89.77 89.77 89.59 89.38 89.43 86.49
86.59 Mn 179192 163277 152061 153749 139436 72972 93130 Mw 332930
231655 209057 202834 183335 147926 147853 Pd 1.86 1.42 1.37 1.32
1.31 2.03 1.59
[0061] TABLE-US-00004 TABLE 4 Sample No. 1 2 3 4 5 6 7 No. of
passes through 0 4 6 8 10 -- -- Homogenizer KV at 100.degree. C. in
Ref. 13.784 11.305 10.822 10.614 10.501 8.79 9.05 Oil (Est. by TGA)
Thickening Power (by 8.81 6.33 5.85 5.64 5.53 3.82 4.07 TGA)
Thickening Efficiency 2.941 2.369 2.243 2.187 2.156 1.717 1.713 (by
TGA) KV at 100.degree. C. in Ref. 11.06 10.92 10.47 10.31 10.11 --
10.86 oil before shearing KV at 100.degree. C. in Ref. 7.99 9.00
8.95 8.94 8.91 -- 9.72 oil after shearing KV at 100.degree. C. of
Ref. 4.89 4.95 4.95 4.95 4.95 -- 4.95 Oil % Viscosity Loss 26.76
17.58 14.52 13.29 11.87 -- 10.5 SSI % 49.76 32.16 27.54 25.56 23.26
24 19.29
[0062] As shown by the foregoing tables and FIGS. 1-5, a shear
stable copolymer made by passing the copolymer through ten or more
passes of a homogenizer can be tailored to provide a viscosity
modifier that meets the shear stability index (SSI) requirement of
about 23 (Sample 5), and has significantly higher thickening
efficiency (Sample 5) compared to conventional olefin copolymer
viscosity modifiers (Samples 6 and 7). Mechanical shearing of an
olefin copolymer has an added benefit of providing a shear stable
olefin copolymer having a polydispersity of less than 1.5 (Sample
5, Table 3).
[0063] At numerous places throughout this specification, reference
has been made to a number of U.S. Patents. All such cited documents
are expressly incorporated in full into this disclosure as if fully
set forth herein.
[0064] The foregoing embodiments are susceptible to considerable
variation in its practice. Accordingly, the embodiments are not
intended to be limited to the specific exemplifications set forth
hereinabove. Rather, the foregoing embodiments are within the
spirit and scope of the appended claims, including the equivalents
thereof available as a matter of law.
[0065] The patentees do not intend to dedicate any disclosed
embodiments to the public, and to the extent any disclosed
modifications or alterations may not literally fall within the
scope of the claims, they are considered to be part hereof under
the doctrine of equivalents.
* * * * *