U.S. patent application number 14/378373 was filed with the patent office on 2016-02-11 for lubricating composition including esterified copolymer and low dispersant levels suitable for driveline applications.
The applicant listed for this patent is Mark R. Baker, William R.S. Barton, Marina Baum, Lynsey Hickman, Daniel C. Visger. Invention is credited to Mark R. Baker, William R.S. Barton, Marina Baum, Lynsey Hickman, Daniel C. Visger.
Application Number | 20160040089 14/378373 |
Document ID | / |
Family ID | 47747860 |
Filed Date | 2016-02-11 |
United States Patent
Application |
20160040089 |
Kind Code |
A1 |
Baker; Mark R. ; et
al. |
February 11, 2016 |
Lubricating Composition Including Esterified Copolymer And Low
Dispersant Levels Suitable For Driveline Applications
Abstract
A lubricating composition, method of making, and method of use
are disclosed. The lubricant includes an esterified copolymer
including a backbone that includes units derived from a vinyl
aliphatic monomer and units derived from a carboxylic acid monomer,
the carboxylic acid monomer comprising an
.alpha.,.beta.-ethylenically unsaturated dicarboxylic acid or
derivative thereof. The lubricating composition also includes an
oil of lubricating viscosity. The lubricating composition includes
no more than 2.5 wt. % of dispersant for dispersing oxidation
products, other than the esterified copolymer.
Inventors: |
Baker; Mark R.; (Midland,
MI) ; Baum; Marina; (Chagrin Falls, OH) ;
Hickman; Lynsey; (Chesterfield, GB) ; Visger; Daniel
C.; (Mentor, OH) ; Barton; William R.S.;
(Belper, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Baker; Mark R.
Baum; Marina
Hickman; Lynsey
Visger; Daniel C.
Barton; William R.S. |
Midland
Chagrin Falls
Chesterfield
Mentor
Belper |
MI
OH
OH |
US
US
GB
US
GB |
|
|
Family ID: |
47747860 |
Appl. No.: |
14/378373 |
Filed: |
August 22, 2013 |
PCT Filed: |
August 22, 2013 |
PCT NO: |
PCT/US2013/026009 |
371 Date: |
August 13, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61599992 |
Feb 17, 2012 |
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|
Current U.S.
Class: |
508/192 ;
508/306 |
Current CPC
Class: |
C10M 2203/02 20130101;
C10M 157/04 20130101; C10N 2040/30 20130101; C10M 2203/1025
20130101; C10M 145/16 20130101; C10N 2040/045 20200501; C10M
2223/043 20130101; C10M 2219/022 20130101; C10N 2040/042 20200501;
C10M 2217/06 20130101; C10N 2040/04 20130101; C10M 2215/28
20130101; C10M 2205/0285 20130101; C10N 2040/08 20130101; C10N
2040/20 20130101; C10N 2060/06 20130101; C10M 2209/084 20130101;
C10N 2020/02 20130101; C10M 149/00 20130101; C10N 2020/04 20130101;
C10N 2030/10 20130101; C10N 2040/044 20200501; C10N 2040/25
20130101; C10N 2060/09 20200501; C10N 2040/046 20200501; C10M
2215/08 20130101; C10N 2030/04 20130101; C10M 2205/028 20130101;
C10M 2205/028 20130101; C10M 2209/086 20130101; C10M 2215/28
20130101; C10N 2060/14 20130101; C10M 2203/1025 20130101; C10N
2020/02 20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101;
C10M 2215/28 20130101; C10N 2060/14 20130101 |
International
Class: |
C10M 157/04 20060101
C10M157/04 |
Claims
1. A lubricating composition comprising: a) an esterified copolymer
with a backbone comprising units derived from a vinyl aliphatic
monomer and units derived from a carboxylic acid monomer, the
carboxylic acid monomer comprising an .alpha.,.beta.-ethylenically
unsaturated dicarboxylic acid or derivative thereof; b) an oil of
lubricating viscosity; and wherein the lubricating composition
comprises no more than 2.5 wt. % of dispersant for dispersing
oxidation products, other than the esterified copolymer.
2. The lubricating composition of claim 1, wherein the lubricating
composition comprises no more than 2 wt. %, or no more than 1.75
wt. %, or no more than 1.5 wt. %, or no more than 1 wt. %, or no
more than 0.5 wt. %, or no more than 0.2 wt. % or no more than 0.1
wt. % dispersant, other than the exemplary copolymer.
3. The lubricating composition of claim 1, wherein the lubricating
composition comprises dispersant, other than the exemplary
copolymer, at 0.01-2.5 wt. %, or at 0.01-2 wt. %, or at 0.01-1.75
wt. %, or at 0.01-1.5 wt. %, or at 0.5-2.5 wt. %, or at 0.5-1.75
wt. %, or at 0.5-1.5 wt. %.
4. The lubricating composition of claim 1, wherein the dispersant
is present and consists essentially of a nitrogen-containing
dispersant derived from an acylated C3-C6 polyalkylene
compound.
5. The lubricating composition of claim 1, wherein the esterified
copolymer comprises a nitrogen-containing group.
6. The lubricating composition of claim 1, wherein at least some of
the units derived from the carboxylic acid monomer are at least one
of aminated, amidated, and imidated with a nitrogen-containing
compound.
7. The lubricating composition of claim 6, wherein the
nitrogen-containing compound is an amine-containing compound
selected from the group consisting of morpholines,
imidazolidinones, amino amides, .beta.-alanine alkyl esters,
aliphatic amines, aromatic amines, aliphatic polyamines, aromatic
polyamines, and mixtures thereof.
8. The lubricating composition of claim 6, wherein 0.1 to 25% of
carboxylic acid functionalities of the units derived from the
carboxylic acid monomer are at least one of aminated, amidated, and
imidated with a nitrogen-containing compound.
9. The lubricating composition of claim 8, wherein at least 1% of
carboxylic acid functionalities on the units derived from the
carboxylic acid monomer are reacted with a nitrogen-containing
compound to provide a nitrogen-containing group.
10. The lubricating composition of claim 1, wherein the esterified
copolymer is substantially free of a nitrogen-containing group.
11. The lubricating composition of claim 10, wherein the
lubricating composition comprises no more than 2 wt. % dispersant,
other than the exemplary copolymer.
12. The lubricating composition of claim 1, wherein the esterified
copolymer has a weight average molecular weight of
5,000-25,000.
13. The lubricating composition of claim 12, wherein the esterified
copolymer has a weight average molecular weight of 5000 to 10,000,
or 15,000-25,000, or 10,000 to 17,000.
14. The lubricating composition of claim 1, wherein the esterified
copolymer is at least 5 wt. % of the lubricating composition.
15. The lubricating composition of claim 1, wherein the esterified
copolymer is at least 10 wt. %, or at least 40 wt. %, or at least
60 wt. % of the lubricating composition.
16. The lubricating composition of claim 1, wherein the esterified
copolymer is 30-60 wt. %, or 40-50 wt. % of the lubricating
composition.
17. The lubricating composition of claim 1, wherein the oil of
lubricating viscosity is at least 20 wt. %, or at least 30 wt. % of
the lubricating composition.
18. The lubricating composition of claim 1, wherein the copolymer
is esterified with a primary alcohol.
19. The lubricating composition of claim 18, wherein the primary
alcohol comprises a primary alcohol which is branched at the
.beta.- or higher position.
20. The lubricating composition of claim 18, wherein the primary
alcohol further comprises a linear primary alcohol.
21. The lubricating composition of claim 18, wherein the primary
alcohol comprises at least 6 carbon atoms.
22. The lubricating composition of claim 1, wherein the carboxylic
acid monomer comprises maleic anhydride.
23. The lubricating composition of claim 1, wherein the vinyl
aliphatic monomer comprises an alpha-olefin.
24. The lubricating composition of claim 23, wherein the
alpha-olefin comprises at least 6 carbon atoms.
25. The lubricating composition of claim 1, wherein a molar ratio
of the vinyl aliphatic monomer units to the carboxylic acid monomer
units in the copolymer is from 1:3 to 3:1, or from 0.6:1 to 1.2:1,
or from 0.7:1 to 1:1.1.
26. The lubricating composition of claim 1, wherein the esterified
copolymer backbone further comprises units derived from a vinyl
aromatic monomer.
27. The lubricating composition of claim 26, wherein a molar ratio
of the units derived from the vinyl aromatic monomer to the units
derived from the vinyl aliphatic monomer is from 0:100 to 25:75, or
up to 10:90.
28. The lubricating composition of claim 1, wherein the copolymer
backbone comprises at least 20 of the units, or at least 100 of the
units.
29. The lubricating composition of claim 1, wherein the copolymer
backbone comprises up to 1000 of the units, or up to 500 of the
units, or up to 250 of the units derived from the vinyl aliphatic
monomer and the carboxylic acid monomer.
30. The lubricating composition of claim 1, further comprising at
least one performance additive, other than the esterified
copolymer.
31. The lubricating composition of claim 30, wherein the at least
one other performance additive comprises at least one of the group
consisting of metal deactivators, detergents, viscosity index
improvers, friction modifiers, corrosion inhibitors, antiwear
agents, extreme pressure agents, antiscuffing agents, antioxidants,
foam inhibitors, demulsifiers, pour point depressants, seal
swelling agents, and mixtures thereof.
32. The lubricating composition of claim 31, wherein the at least
one other performance additive comprises an extreme pressure agent
selected from the group consisting of dimercapto-1,3,4-thiadiazole,
derivatives of dimercapto-1,3,4-thiadiazole, sulfurized olefins,
and mixtures thereof.
33. The lubricating composition of claim 1, wherein the lubricating
composition comprises, in total, less than 2 wt. %, or less than
1.75 wt. %, or less than 1.5 wt. %, or less than 1 wt. %, or less
than 0.5 wt. %, or less than 0.2 wt. % of dispersants selected from
the group consisting of N-substituted long chain alkenyl
succinimides, polyisobutylene succinimide complexed with zinc,
Mannich bases, and post-treated dispersants formed by borating
these compounds.
34. The lubricating composition of claim 1, wherein the 20 hr KRL
SSI of the lubricating composition is from 0-30, or from 0-10, or
from 10-30.
35. A process for preparing a lubricating composition comprising:
(A) forming an esterified copolymer comprising: (1) reacting (i) a
vinyl aliphatic monomer and (ii) a carboxylic acid monomer
comprising an .alpha.,.beta.-ethylenically unsaturated dicarboxylic
acid or derivative thereof, to form a copolymer, wherein the
carboxylic acid monomer optionally has ester groups, (2)
optionally, esterifying the copolymer of step (1) to form an
esterified copolymer, and (3) optionally, reacting the copolymer of
step (1) or (2) with an nitrogen-containing compound in an amount
to provide an esterified copolymer with at least 0.01 wt. %
nitrogen; and wherein the resulting copolymer is esterified in at
least one of (1), (2), and (3); and (B) mixing the esterified
copolymer formed in (A) with at least one of an oil of lubricating
viscosity and a performance additive other than the esterified
copolymer, to provide a lubricating composition comprising no more
than 2.5 wt. % of dispersant, other than the esterified copolymer,
for dispersing oxidation products.
36. The process of claim 35, comprising step (3).
37. The process of claim 35, wherein the reacting of the esterified
copolymer of step (1) or (2) with an nitrogen-containing compound
provides the esterified copolymer with 0.01 wt. % to 1.5 wt. %, or
0.02 wt. % to 0.75 wt. %, or 0.04 wt. % to 0.25 wt. % nitrogen.
38. The process of claim 35, comprising step (2).
39. The process of claim 35, wherein the carboxylic acid monomer
has ester groups derived from a primary alcohol to provide an
esterified copolymer in step (1).
40. A lubricating composition formed by the method of claim 35.
41. (canceled)
42. A method for lubricating a component of a driveline system of a
vehicle comprising supplying the lubricating composition of claim 1
to the component.
Description
FIELD OF INVENTION
[0001] The present embodiment relates to a lubricating composition
comprising an esterified copolymer formed from a vinyl aliphatic
monomer and an .alpha.,.beta.-ethylenically unsaturated
dicarboxylic acid or derivative thereof. The lubricating
composition may further include an oil of lubricating viscosity.
The copolymer serves as a dispersant in the lubricating composition
for dispersing oxidation products generated during operation of the
mechanical device, obviating the need for any other dispersants of
the type conventionally used in driveline applications. The
lubricating composition finds application in vehicle driveline
systems, such as for an automotive gear oil. The invention further
provides a method and use of the lubricating composition by
supplying it to a driveline component of a vehicle, such as a gear
box.
BACKGROUND
[0002] Lubricants for driveline power transmitting devices (such as
gears or transmissions), especially automatic transmission fluids
(ATFs), and manual transmission fluids (MTFs), and axle fluids,
present challenges in satisfying lubricating requirements, whilst
providing durability and cleanliness.
[0003] Lubricants have conventionally been prepared with
polyalphaolefins, or bright stock (lubricating oils of high
viscosity, obtained from the residues of petroleum distillation).
To impart the desired viscometric properties in lubricants,
viscosity index improvers, sometimes referred to as viscosity
modifiers, have been added to lubricating oil compositions to
change the viscosity index. Typical viscosity index improvers for
gear oils include oil soluble polyisobutylenes, low molecular
weight polymers of methacrylates and acrylates, olefin copolymers,
and polyalphaolefins, such as PAO 100. When subject to high shear
and high temperature, such lubricating oils can undergo oxidation.
The byproducts of the oxidation can be harmful to driveline
components, particularly since the lubricating oils are seldom, if
ever replaced. Thus, a dispersant is commonly added to the
lubricant. Dispersants attach themselves to contaminant particles
and hold them in suspension, thereby reducing deposition of the
oxidation products. Conventional dispersants include ashless-type
dispersants such as N-substituted long chain alkenyl succinimides,
polyisobutylene succinimide complexed with zinc, Mannich bases, and
post-treated dispersants formed by borating these compounds.
[0004] International Application WO2007/133999 discloses a polymer
with pendent groups which may be a copolymer of an .alpha.-olefin
and an unsaturated diacid or an anhydride thereof. The polymers may
incorporate ester functionality in pendent groups. The ester
functional groups may be derived from linear or branched alkyl
alcohols. The polymers of WO 2007/133999 are said to be useful in a
lubricant to provide at least one of acceptable dispersancy
properties, acceptable shear stability, acceptable viscosity index
control, and acceptable low temperature viscosity.
[0005] Examples of other polymers are disclosed in U.S. Pat. Nos.
5,435,928; 6,174,843; 6,419,714; 6,544,935; and 7,254,249; and in
International Application No. WO 2010/014655.
[0006] U.S. Pat. No. 5,188,745 discloses a lubricating oil
composition which includes an additive composition comprising a
graft and derivatized copolymer prepared by reacting ethylene and
at least one C.sub.3-C.sub.10 alpha-monoolefin and, optionally, a
polyene selected from non-conjugated dienes and trienes, which has
been reacted with at least one olefinic carboxylic acid acylating
agent to form one or more acylating reaction intermediates having a
carboxylic acid acylating function within their structure and by
reacting the reaction intermediate with a
N-(2-aminoalkyl)imidizolidone to form the graft derivatized
copolymer.
[0007] The exemplary embodiment provides a lubricating composition
with oxidative stability and improved cleanliness which can be
achieved with only low amounts of a dispersant or without the use
of a dispersant, other than an esterified copolymer as disclosed
herein.
BRIEF DESCRIPTION
[0008] In accordance with one aspect of the exemplary embodiment, a
lubricating composition includes an esterified copolymer including
a backbone comprising units derived from a vinyl aliphatic monomer
and units derived from a carboxylic acid monomer, the carboxylic
acid monomer comprising an .alpha.,.beta.-ethylenically unsaturated
dicarboxylic acid or derivative thereof. The lubricating
composition also includes an oil of lubricating viscosity. The
lubricating composition comprises no more than 2.5 wt. % of
dispersant for dispersing oxidation products, other than the
esterified copolymer.
[0009] In another aspect, a process for preparing a lubricating
composition includes forming an esterified copolymer, including (1)
reacting (i) a vinyl aliphatic monomer and (ii) a carboxylic acid
monomer comprising an .alpha.,.beta.-ethylenically unsaturated
dicarboxylic acid or derivative thereof, to form a copolymer,
wherein the carboxylic acid monomer optionally has ester groups,
(2) optionally, esterifying the copolymer of step (1) to form an
esterified copolymer, and (3) optionally, reacting the copolymer of
step (1) or (2) with an nitrogen-containing compound in an amount
to provide an esterified copolymer with at least 0.01 wt. %
nitrogen; and whereby the resulting copolymer is esterified in at
least one of (1), (2), and (3) and mixing the esterified copolymer
thus formed with at least one of an oil of lubricating viscosity
and a performance additive other than the esterified copolymer, to
provide a lubricating composition comprising no more than 2.5 wt. %
of dispersant, other than the esterified copolymer, for dispersing
oxidation products.
DETAILED DESCRIPTION
[0010] The present embodiment relates to a lubricating composition
comprising an esterified copolymer as disclosed herein
("copolymer") which includes units derived from a polymerizable
vinyl aliphatic monomer and units derived from an
.alpha.,.beta.-ethylenically unsaturated dicarboxylic acid or
derivative thereof (referred to herein collectively as a carboxylic
acid monomer). In one embodiment, the exemplary copolymer is
capable of reducing the effects of oxidation of the lubricating
composition, when used in a mechanical device. In one embodiment,
the copolymer is useful as a base oil replacement in the
lubricating composition. Other aspects relate to a method for
lubricating a mechanical device with the lubricating composition.
The exemplary mechanical device is a vehicle driveline device
including a gear or transmission system.
[0011] The lubricating composition is substantially free of
dispersants. By "substantially free" it is meant that the
lubricating composition, as formulated for use in a driveline
system, includes no more than a total of 2.5 wt. % of all
dispersants, other than the exemplary esterified copolymer, which
provide for dispersion of oxidation products generated during use
of the lubricating composition in a mechanical device. For example,
the lubricating composition may include from 0-2.5 wt. % of such
dispersant(s), other than the exemplary copolymer, or no more than
2 wt. %, or no more than 1.75 wt. %, or no more than 1.5 wt. %, or
no more than 1 wt. %, or no more than 0.5 wt. %, or no more than
0.25 wt. %, or no more than 0.2 wt. %, or no more than 0.1 wt. %,
or no more than 0.01 wt. % of such dispersant(s). The amount of
dispersant excludes any oil or other diluent with which it may be
mixed prior to incorporation of the dispersant into the
composition. In one embodiment, the lubricating composition is
dispersant free, by which it is meant that the lubrication
composition contains no added dispersant, although a dispersant may
be present in trace amounts of up to 0.001 wt. % or up to 0.0001
wt. % of the lubricating composition.
[0012] By "dispersant," it is meant any of the performance
additives commonly added to lubricating oils for their dispersancy
characteristics, in particular, for dispersing oxidation products
generated in the lubricating composition during operation of a
mechanical device, such as a gear or transmission system. Such
dispersants include ashless-type dispersants such as N-substituted
long chain alkenyl succinimides, polyisobutylene succinimide
complexed with zinc, Mannich bases, acylated polyalkylene
polyamines, and post-treated dispersants formed by borating these
compounds. By "long chain" it is meant a chain of at least 6, or at
least 12, or 24, or 30 carbon atoms. Examples of such dispersants
are given below, with the understanding that the total of all such
dispersants is limited to the amounts provided herein, and in one
embodiment, that they are entirely absent from the exemplary
lubricating composition (other than as trace amounts).
[0013] The term "copolymer," as used herein, generally refers to a
polymer derived from two or more different monomers. The exemplary
copolymer has a backbone which is derived from two (or more)
different monomers.
[0014] The exemplary esterified copolymer disclosed herein includes
a polymeric backbone which includes units derived from the vinyl
aliphatic monomer and units derived from the carboxylic acid
monomer. The backbone can be a chain comprising units derived from
the selected monomers that are linked together such that the
backbone comprises a chain of at least 10 such units, or at least
20 or at least 50 such monomer units. In one embodiment, the
backbone chain of monomer units derived from the selected monomers
is of no more than 1000 such monomer units, or no more than 500
such monomer units, or no more than 200 such monomer units. In the
exemplary copolymer, a majority of the backbone, (such as at least
60%, or at least 70%, or at least 80%, or at least 90%, or at least
95%, such as 70%-95%, and up to 100% of the units in the backbone),
is derived from the vinyl aliphatic monomer and the carboxylic acid
monomer. Pendent groups may be grafted to the backbone, such as by
esterification and/or amidization/imidization of the units of the
backbone that are derived from the carboxylic acid monomer.
[0015] The polymeric backbone of the copolymer may be a generally
alternating structure whereby each carboxylic acid unit (or at
least a majority thereof) is spaced from the next carboxylic acid
unit by at least one vinyl aliphatic monomer unit, each carboxylic
acid unit being derived from a carboxylic acid monomer which can be
the same or different, and wherein each vinyl aliphatic monomer
unit can be derived from the same or a different vinyl aliphatic
monomer. A molar ratio of the vinyl aliphatic monomer units to
carboxylic acid monomer units in the copolymer can be for example,
from 1:3 to 3:1 or from 0.6:1 to 1.2:1. In one embodiment, the
molar ratio is about 0.7:1 to 1:1.1 in the copolymer. It is to be
appreciated, however, that the molar ratios used in the preparation
of the copolymer may differ from those in the copolymer.
Additionally, when units of a third monomer are present in the
copolymer, the ratio of the vinyl aliphatic monomer units to
carboxylic acid monomer units may be modified slightly to
accommodate these units.
[0016] In one embodiment, the backbone chain comprising units
derived from the selected monomers may further comprise units
derived from a vinyl aromatic monomer, such that, for example, no
more than 25%, or no more than 15%, or no more than 10% or no more
than 5% of the monomer units of the backbone chain are derived from
the vinyl aromatic monomer.
[0017] The exemplary copolymer further includes an ester group
formed, for example, by esterification of at least some of the
carboxylic acid units of the copolymer with a primary alcohol, such
as one or more of a linear alcohol and a branched alcohol.
[0018] The exemplary esterified copolymer further includes a
nitrogen containing group (such as amino-, amido- and/or
imido-group) formed, for example, from a nitrogen containing
compound capable of being incorporated during copolymerization. In
one embodiment, the nitrogen containing group forms a salt of the
carboxylic acid unit, for example, by reaction of the carboxylic
acid unit with an amine without driving off water.
[0019] A process for forming the exemplary lubricating composition
can comprise the steps of: (A) forming an esterified copolymer with
nitrogen-containing groups and (B), mixing the esterified copolymer
formed in (A) with at least one of (i) an oil of lubricating
viscosity and (ii) a performance additive, other than the exemplary
copolymer. Step (A) may include: [0020] (1) reacting (i) a vinyl
aliphatic monomer, such as an .alpha.-olefin (and optionally, a
vinyl aromatic monomer, such as styrene), and (ii) a carboxylic
acid monomer, such as maleic acid or a derivative thereof, such as
maleic anhydride, to form a copolymer; wherein the carboxylic acid
monomer optionally has ester groups, e.g., derived from a primary
alcohol; [0021] (2) optionally, esterifying the copolymer of step
(1), e.g., with a primary alcohol, to form an esterified copolymer;
and [0022] (3) optionally, reacting the copolymer of step (2) with
an nitrogen-containing compound, such as amine, in an amount to
provide the esterified copolymer with, for example, 0.01 wt. % to
1.5 wt. % (or 0.05 wt. % to 0.75 wt. %, or 0.075 wt. % to 0.25 wt.
%) nitrogen; and [0023] wherein the copolymer is esterified, e.g.,
in one or more of steps (1), (2), and (3).
[0024] In one embodiment, each of steps (1), (2), and (3) is
performed. In this embodiment, the carboxylic acid monomer used in
step (1) need not have ester groups.
[0025] In another embodiment, the carboxylic acid monomer may be
esterified, e.g., with a primary alcohol prior to step (1), and
step (2) may be omitted.
[0026] In another embodiment, steps (1) and (3) are performed and
the nitrogen-containing compound provides the ester groups, in
which case, step (2) may be omitted.
[0027] In another embodiment, the esterified copolymer is
substantially free of a nitrogen-containing group, i.e., contains
no more than 0.01 wt. % nitrogen.
[0028] By way of example, the exemplary copolymer can include a
polymeric backbone of poly(alpha-olefin maleic anhydride), derived
from 1-dodecene, as the vinyl aliphatic monomer, and maleic
anhydride, as the carboxylic acid monomer, which is esterified with
one or more primary alcohols by which pendent groups are grafted to
the backbone to provide an esterified copolymer (poly(alpha-olefin
maleic anhydride diester)) and which has been reacted with a
nitrogen-containing compound (such as 4-(3-aminopropyl)morpholine
or 1-(2-aminoethyl)imidazolidinone) to provide the esterified
copolymer with from 0.01-1.5 wt. %, such as 0.05-0.2 wt. %
nitrogen.
[0029] A lubricating composition ("oil") can be formed by admixing
the exemplary copolymer with (i) an oil of lubricating viscosity
(which may be referred to herein as a base oil), and optionally
(ii) one or more other performance additives (other than
dispersants at more than the amounts specified herein).
[0030] A lubricating composition can also be formed by admixing the
exemplary copolymer with one or more other performance additives
(other than dispersants at more than the amounts specified herein),
in the absence of an oil of lubricating viscosity.
[0031] The lubricating composition can include 5-75 wt. % of the
exemplary copolymer, or 10-60 wt. %, or 30-60 wt. %, or 40-50 wt.
%. Example lubricating compositions include 5-30 wt. %, or 5-20 wt.
%, or 5-15 wt. %, or 5-10 wt. %, or 20-40 wt. % of the exemplary
copolymer.
[0032] Weight average molecular weight (M.sub.w) as used herein, is
measured by gel permeation chromatography (GPC), also known as
size-exclusion chromatography, employing a polystyrene standard.
Typically the weight average molecular weight is measured on the
final esterified copolymer, optionally reacted with a
nitrogen-containing compound. The M.sub.w of the exemplary polymer,
before esterification, can range from 3000 to 50,000, and in one
embodiment, may be 3000 to 20,000, such as at least 10,000.
[0033] The M.sub.w of the exemplary polymer, after esterification
and optional reaction with the nitrogen-containing compound, can
range from 5000 to 50,000, and in one embodiment, may be 5000 to
25,000, or 10,000 to 17,000, or 5000 to 10,000, or 12,000 to
18,000, or 9,000 to 15,000, or 15,000 to 20,000.
[0034] The viscosity of the copolymer (e.g., in a lubricating
composition) can be determined under ambient conditions, at low
temperature (Brookfield viscosity), or under shear conditions. The
viscosity shear stability index (SSI) of transmission lubricants,
which measures the stability of the copolymer in a lubricating
composition under shear conditions, can be measured by a 20 hour
KRL test (Volkswagen Tapered Bearing Roller Test), as set out in
standard CEC L-45-99 and DIN 51350-6-KRL/C. The 20 hr KRL SSI of
the exemplary lubricating composition may be from 0-30 SSI, or 0-10
SSI, or 10-30 SSI (i.e., low permanent shear loss) under the CEC
L-45-99 method, when subjected to tapered roller bearing shear
(5000N, 1475 RPM, 60.degree. C.).
[0035] One method for assessing the ability of the exemplary
copolymer to improve the dispersing of oxidized material is to
evaluate the lubricating composition for oxidative stability. This
may be performed by DKA oxidation testing using the method
described in CEC L-48-00, Oxidation Stability of Lubricating Oils
used in Automotive Transmissions by Artificial Ageing (Laboratory
Test) available from the Coordinating European Council for the
development of performance tests for fuels, lubricants, and other
fluids (CEC). In the exemplary method, the tests are run using the
oxidation procedure as described in CEC L-48-00 procedure B whereby
air is passed through 100 ml of oil at a rate of 5 liters/hour for
192 hours at 160.degree. C. The results are expressed as the
percentage increase in kinematic viscosity at 40.degree. C. (%
KV40) and at 100.degree. C. (% KV100). Typically, lower values
recorded for the % increase in KV100 indicate improved
performance.
[0036] Additionally, a test which has been used to determine the
dispersive condition of a lubricating composition, either a test
oil which has been subjected to oxidation testing or one which has
been used in field service, is to assess the relative undispersed
sludge spot size of the oil which has been placed on an absorbent
material. This method involves placing a measured drop of the
oxidized oil (at room temperature), onto the center of a filter
paper using a disposable pipette and allowing the spot to develop.
The filter paper is placed in a drying oven at 80.degree. C.
(.+-.10.degree. C.) for one hour (.+-.15 minutes). The dispersed
oil sample appears as a circular spot on the absorbent material
whilst any undispersed sludge may appear as a darker inner circular
spot. The dispersancy rating is calculated as:
Dispersancy rating = diameter of the inner ( non - dispersing
sludge ) spot Diameter of the outer dispersed spot ##EQU00001##
[0037] The Copolymer
[0038] A. The Vinyl Aliphatic Monomer Units
[0039] The copolymer includes vinyl aliphatic monomer units derived
from a vinyl aliphatic monomer. An exemplary vinyl aliphatic
monomer is a polymerizable aliphatic monomer, specifically, an
aliphatic compound substituted with a vinyl group
(--CH.dbd.CH.sub.2). Examples of vinyl aliphatic monomers include
alpha-olefins selected from C.sub.6-C.sub.30 alpha-olefins such
C.sub.8-C.sub.20 alpha-olefins, or C.sub.10-C.sub.18 alpha-olefins,
or C.sub.10-C.sub.14 alpha-olefins. The alpha-olefin can be linear
or branched. Examples of suitable linear alpha-olefins include
1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene,
1-pentadecene, 1-hexadecene, 1-heptadecene 1-octadecene, and
mixtures thereof. An example of a useful vinyl aliphatic monomer is
1-dodecene.
[0040] B. The Carboxylic Acid Monomer Units
[0041] The .alpha.,.beta.-ethylenically unsaturated carboxylic acid
or derivative thereof used in forming the carboxylic acid units of
the copolymer may be a dicarboxylic acid or an anhydride or other
derivative thereof that may be wholly esterified, partially
esterified, or a mixture thereof. When partially esterified, other
functional groups may include acids, salts or mixtures thereof.
Suitable salts include alkali metals, alkaline earth metals, and
mixtures thereof. The salts may include lithium, sodium, potassium,
magnesium, calcium or mixtures thereof.
[0042] Exemplary unsaturated carboxylic acids or derivatives
thereof which may be used in forming the carboxylic acid units of
the copolymer include acrylic acid, methyl acrylate, methacrylic
acid, maleic acid, fumaric acid, itaconic acid, alpha-methylene
glutaric acid, and anhydrides and mixtures thereof, and substituted
equivalents thereof. Suitable examples of monomers for forming the
carboxylic acid unit include itaconic anhydride, maleic anhydride,
methyl maleic anhydride, ethyl maleic anhydride, dimethyl maleic
anhydride, and mixtures thereof. In one embodiment, the carboxylic
acid unit, includes units derived from maleic anhydride or
derivatives thereof.
[0043] In the exemplary unsaturated carboxylic acids or derivatives
thereof, a carbon-to-carbon double bond is typically in an alpha,
beta-position relative to at least one of the carboxy functions
(e.g., in the case of itaconic acid, anhydride or esters thereof)
and may be in an alpha, beta-position to both of the carboxy
functions of an alpha, beta-dicarboxylic acid, anhydride or the
ester thereof (e.g., in the case of maleic acid or anhydride,
fumaric acid, or ester thereof). In one embodiment, the carboxy
functions of these compounds will be separated by up to 4 carbon
atoms, such as 2 carbon atoms.
[0044] Other suitable monomers for forming the carboxylic acid
monomer unit of the exemplary copolymer are described in U.S. Pub.
No. 20090305923.
[0045] C. Optional Units
[0046] In one embodiment, the backbone chain, in addition to the
vinyl aliphatic monomer units and carboxylic monomer units, may
further include other monomer-derived units capable of polymerizing
with one or both of the vinyl aliphatic monomer units and
carboxylic monomer units. These additional units may be randomly
incorporated throughout the copolymer backbone or may be in the
form of a block or blocks. The copolymer may comprise in total, up
to 30 mole %, or up to 20 mole %, or up to 10 mole % of such
optional units. As an example of such optional units are derived
from a vinyl aromatic monomer or (meth)acrylate. An exemplary vinyl
aromatic monomer, where present, is a polymerizable aromatic
monomer, specifically, an aromatic compound substituted with a
vinyl group (--CH.dbd.CH.sub.2).
[0047] Suitable vinyl aromatic monomers are those corresponding to
Formula I:
##STR00001##
[0048] wherein R.sup.1 and R.sup.2 independently represent a
hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a
halogen containing group. The vinyl aromatic monomer may be
selected from styrene, alpha-alkylstyrenes, nuclear alkylstyrenes,
chlorostyrenes, dichlorostyrenes, vinylnaphthalene, and mixtures of
these. Specific examples include styrene, alpha-methylstyrene,
alpha-ethylstyrene, alpha-isopropylstyrene,
alpha-tert-butylstyrene, nuclear alkylstyrenes such as
o-methylstyrene, m-methylstyrene, p-methylstyrene,
o-methyl-alpha-methylstyrene, m-methyl-alpha-methylstyrene,
p-methyl-alpha-methylstyrene, m-isopropyl-alpha-methylstyrene,
p-isopropyl-alpha-methylstyrene, m-isopropylstyrene,
p-isopropylstyrene, vinylnaphthalene, and mixtures thereof.
[0049] D. Alcohols for Esterification of the Carboxylic Acid
Unit
[0050] The carboxylic acid unit of the copolymer may be wholly or
partially esterified with a primary alcohol. The ester groups are
usually formed by reacting the carboxy-containing copolymer with
alcohols, although in some embodiments, especially for lower alkyl
esters, the ester group may be incorporated from one of the
monomers used to prepare the copolymer.
[0051] Suitable primary alcohols for use herein may contain 8 to
60, or 8 to 40, or 8 to 24, or 8-16 carbon atoms, such as 8-10
carbon atoms. The primary alcohol may be linear or may be branched
at the .alpha.- or .beta.- or higher position. In one embodiment, a
mixture of linear and branched alcohols is employed in forming the
esterified copolymer described herein. In one exemplary embodiment,
at least 0.1% of the carboxylic acid units in the copolymer are
esterified with an alcohol branched at .beta.- or higher
position.
[0052] In one embodiment, 20 to 100 mole %, or 30 to 100 mole %, or
30 to 70 mole %, based on the total number of moles of carboxyl
groups in the copolymer contain ester groups having 12 to 19 carbon
atoms in the alcohol group (that is, in the alcohol-derived or
alkoxy portion of the ester) and 70 or 80 to 100 mole %,
alternatively 80 to 30 mole %, based on the total number of moles
of carboxyl groups in the copolymer, contain ester groups having 8
to 10 carbon atoms in the alcohol portion. In one embodiment, the
esterified copolymer contains at least 45 mole %, based on moles of
carboxyl groups in the esterified copolymer, of ester groups
containing from 12 to 18 carbon atoms in the alcohol portion. In an
optional embodiment, the esterified copolymer has up to 20 mole %
or 0 to 5% or 1 to 2%, based on the total number of moles of
carboxyl groups in the copolymer, of ester groups having from 1 to
6 carbon atoms in the alcohol portion. In one embodiment, the
compositions are substantially free of ester groups containing from
3 to 7 carbon atoms.
[0053] In one embodiment, 0.1 to 99.89 (or 1 to 50, or 2.5 to 20,
or 5 to 15) percent of the carboxylic acid units esterified are
esterified with a primary alcohol branched at the .beta.- or higher
position, 0.1 to 99.89 (or 1 to 50, or 2.5 to 20, or 5 to 15)
percent of the carboxylic acid units esterified are esterified with
a linear alcohol or an alpha-branched alcohol, and 0.01 to 10% (or
0.1% to 20%, or 0.02% to 7.5%, or 0.1 to 5%, or 0.1 to less than
2%) of the carboxylic acid units has at least one
nitrogen-containing group, such as an amino-, amido- and/or
imido-group, and/or a salt formed between the amine and the
carboxylic acid, as described below. As an example, 5 to 15 percent
of the carboxylic acid units of the copolymer are esterified with a
primary alcohol branched at the 0- or higher position, 0.1 to 95
percent of the carboxylic acid units are esterified with a linear
alcohol or an alpha-branched alcohol, and 0.1 to less than 2% of
the carboxylic acid units has at least one nitrogen-containing
group.
[0054] Examples of useful primary alcohols include butanol,
heptanol, octanol, 2-ethylhexanol, decanol, dodecanol, tridecanol,
tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol,
and combinations thereof.
[0055] Other exemplary primary alcohols include commercially
available mixtures of alcohols. These include oxoalcohols which may
comprise, for example, various mixtures of alcohols having from
8-24 carbon atoms. Of the various commercial alcohols useful
herein, one contains 8 to 10 carbon atoms, and another 12 to 18
aliphatic carbon atoms. The alcohols in the mixture may include one
or more of, for example, octyl alcohol, decyl alcohol, dodecyl
alcohol, tetradecyl alcohol, pentadecyl alcohol, and octadecyl
alcohol. Several suitable sources of these alcohol mixtures are the
technical grade alcohols sold under the name NEODOL.RTM. alcohols
(Shell Oil Company, Houston, Tex.) and under the name ALFOL.RTM.
alcohols (Sasol, Westlake, La.), and fatty alcohols derived from
animal and vegetable fats and sold commercially by, for example,
Henkel, Sasol, and Emery.
[0056] Tertiary alkanolamines, i.e., N,N-di-(lower alkyl)amino
alkanolamines, are other alcohols that may be used to prepare the
esterified copolymers. Examples include N,N-dimethylethanolamine,
N,N-diethylethanolamine, 5-diethylamino-2-pentanol, and
combinations thereof.
[0057] Exemplary primary alcohols branched at the f3- or higher
position may include Guerbet alcohols. Methods to prepare Guerbet
alcohols are disclosed in U.S. Pat. No. 4,767,815 (see column 5,
line 39 to column 6, line 32).
[0058] The primary alcohol branched at the .beta.- or higher
position may be used to provide pendent groups as represented
within ( ).sub.w of the Formula II:
##STR00002##
[0059] wherein [0060] (BB) is a copolymer backbone comprising the
carboxylic acid monomer units and vinyl aliphatic monomer units.
[0061] X is a functional group which either (i) contains a carbon
and at least one oxygen or nitrogen atom or (ii) is an alkylene
group with 1 to 5 carbon atoms (typically --CH.sub.2--), connecting
the copolymer backbone and a branched hydrocarbyl group contained
within ( ).sub.y; [0062] w is the number of pendent groups attached
to the copolymer backbone, which may be in the range of 2 to 2000,
or 2 to 500, or 5 to 250; [0063] y is 0, 1, 2 or 3, provided that
in at least 1 mol. % of the pendent groups, y is not zero; and with
the proviso that when y is 0, X is bonded to a terminal group in a
manner sufficient to satisfy the valence of X, wherein the terminal
group is selected from hydrogen, alkyl, aryl, a metal (typically
introduced during neutralization of ester reactions. Suitable
metals include calcium, magnesium, barium, zinc, sodium, potassium
or lithium) or ammonium cation, and mixtures thereof; [0064] p is
an integer in the range of 1 to 15 (or 1 to 8, or 1 to 4); [0065]
R.sup.3 and R.sup.4 are independently linear or branched
hydrocarbyl groups, and the combined total number of carbon atoms
present in R.sup.3 and R.sup.4 is at least 12 (or at least 16, or
at least 18 or at least 20).
[0066] In different embodiments, the copolymer with pendent groups
may contain 0.10% to 100%, or 2% to 20%, such as 5% to 20%, or 10%
to 18%, branched hydrocarbyl groups represented by a group within (
).sub.y of the Formula II, expressed as a percentage of the total
number of pendent groups. The pendent groups of Formula II may also
be used to define the ester groups as defined above by the phrase
"a primary alcohol branched at the .beta.- or higher position".
[0067] In different embodiments the functional groups defined by X
in Formula II above, may comprise at least one of --CO.sub.2--,
--C(O)N.dbd. or --(CH.sub.2).sub.v--, wherein v is an integer in
the range of 1 to 20, or 1 to 10, or 1 to 2.
[0068] In one embodiment, X is derived from an
.alpha.,.beta.-ethylenically unsaturated dicarboxylic acid or
derivatives thereof. Examples of a suitable carboxylic acid or
derivatives thereof typically include maleic anhydride, maleic
acid, (meth)acrylic acid, itaconic anhydride or itaconic acid. In
one embodiment, the .alpha.,.beta.-ethylenically unsaturated
dicarboxylic acid or derivative(s) thereof may be at least one of
maleic anhydride or maleic acid.
[0069] In one embodiment X is other than an alkylene group,
connecting the copolymer backbone and the branched hydrocarbyl
groups.
[0070] In different embodiments the pendent groups may be
esterified, amidated or imidated functional groups.
[0071] Examples of suitable groups for R.sup.3 and R.sup.4 in
Formula II include: alkyl groups containing C.sub.15-16
polymethylene groups, such as 2-C.sub.1-15 alkyl-hexadecyl groups
(e.g., 2-octylhexadecyl) and 2-alkyl-octadecyl groups (e.g.,
2-ethyloctadecyl, 2-tetradecyl-octadecyl and 2-hexadecyloctadecyl);
alkyl groups containing C.sub.13-14 polymethylene groups, such as
1-C.sub.1-15 alkyl-tetradecyl groups (e.g., 2-hexyltetradecyl,
2-decyltetradecyl and 2-undecyltridecyl) and 2-C.sub.1-15
alkyl-hexadecyl groups (e.g., 2-ethyl-hexadecyl and
2-dodecylhexadecyl); alkyl groups containing C.sub.10-12
polymethylene groups, such as 2-C.sub.1-15 alkyl-dodecyl groups
(e.g., 2-octyldodecyl) and 2-C.sub.1-15 alkyl-dodecyl groups
(2-hexyldodecyl and 2-octyldodecyl), 2-C.sub.1-15 alkyl-tetradecyl
groups (e.g., 2-hexyltetradecyl and 2-decyltetradecyl); alkyl
groups containing C.sub.6-9 polymethylene groups, such as
2-C.sub.1-15 alkyl-decyl groups (e.g., 2-octyldecyl) and
2,4-di-C.sub.1-15 alkyl-decyl groups (e.g., 2-ethyl-4-butyl-decyl);
alkyl groups containing C.sub.1-5 polymethylene groups, such as
2-(3-methylhexyl)-7-methyl-decyl and
2-(1,4,4-trimethylbutyl)-5,7,7-trimethyl-octyl groups; and mixtures
of two or more branched alkyl groups, such as alkyl residues of
oxoalcohols corresponding to propylene oligomers (from hexamer to
undecamer), ethylene/propylene (molar ratio 16:1-1:11) oligomers,
isobutene oligomers (from pentamer to octamer), and C.sub.5-17
.alpha.-olefin oligomers (from dimer to hexamer).
[0072] The pendent groups may contain a total combined number of
carbon atoms on R.sup.3 and R.sup.4 in the range of 12 to 60, or 14
to 50, or 16 to 40, or 18 to 40, or 20 to 36.
[0073] Each of R.sup.3 and R.sup.4 may individually contain 5 to
25, or 8 to 32, or 10 to 18 methylene carbon atoms. In one
embodiment, the number of carbon atoms on each R.sup.3 and R.sup.4
group may be 10 to 24.
[0074] In different embodiments, the primary alcohol branched at
the .beta.- or higher position may have at least 12 (or at least
16, or at least 18 or at least 20) carbon atoms. The number of
carbon atoms may range from at least 12 to 60, or at least 16 to
30.
[0075] Examples of suitable primary alcohols branched at the
.beta.- or higher position include 2-ethylhexanol, 2-butyloctanol,
2-hexyldecanol, 2-octyldodecanol, 2-decyltetradecanol, and mixtures
thereof.
[0076] E. Nitrogen-Containing Group
[0077] The exemplary esterified copolymer includes a nitrogen
containing group, such as an amino-, amido- and/or imido-group. The
nitrogen containing group may be derived from a nitrogen-containing
compound capable of being incorporated during copolymerization (or
through reaction with the carboxylic acid units to form a salt),
such as an amine, amide, imide, or mixture thereof, e.g., through
being aminated (which as used herein includes forming salts of the
carboxylic acid units), amidated, and/or imidated with a
nitrogen-containing compound.
[0078] Examples of suitable nitrogen-containing compounds capable
of being incorporated into the copolymer include
N,N-dimethylacrylamide, N-vinyl carbonamides, such as
N-vinyl-formamide, N-vinylacetamide, N-vinyl propionamides, N-vinyl
hydroxyacetamide, vinyl pyridine, N-vinyl imidazole, N-vinyl
pyrrolidinone, N-vinyl caprolactam, dimethylaminoethyl acrylate,
dimethylaminoethyl methacrylate, dimethylaminobutyl acrylamide,
dimethylaminopropyl methacrylate, dimethylaminopropyl acrylamide,
dimethylaminopropyl methacrylamide, dimethylaminoethyl acrylamide,
and mixtures thereof.
[0079] The copolymer may include a nitrogen containing group that
may be capable of reacting with the esterified copolymer backbone,
typically for capping the copolymer backbone. The capping may
result in the copolymer having ester, amide, imide and/or amine
groups.
[0080] The nitrogen-containing group may be derived from a primary
or secondary amine, such as an aliphatic amine, aromatic amine,
aliphatic polyamine, aromatic polyamine, polyaromatic polyamine, or
combination thereof.
[0081] In one embodiment, the nitrogen containing group may be
derived from an aliphatic amine, such as a C.sub.1-C.sub.30 or
C.sub.1-C.sub.24 aliphatic amine. Examples of suitable aliphatic
amines include aliphatic monoamines and diamines, which may be
linear or cyclic. Examples of suitable primary amines include
methylamine, ethylamine, propylamine, butylamine, pentylamine,
hexylamine, heptylamine, octylamine, decylamine, dodecylamine,
tetradecylamine, hexadecylamine octadecylamine, oleylamine,
dimethylaminopropylamine, diethylaminopropylamine,
dibutylaminopropylamine, dimethylaminoethylamine,
diethylaminoethylamine, and dibutylaminoethylamine. Examples of
suitable secondary amines include dimethylamine, diethylamine,
dipropylamine, dibutylamine, diamylamine, dihexylamine,
diheptylamine, methylethylamine, ethylbutylamine,
diethylhexylamine, and ethylamylamine. The secondary amines may be
cyclic amines such as aminoethylmorpholine, aminopropylmorpholine,
1-(2-aminoethyl)pyrrolidone, piperidine,
1-(2-aminoethyl)piperidine, piperazine and morpholine. Examples of
suitable aliphatic polyamines include tetraethylene pentamine,
pentaethylenehexamine, diethylenetriamine, triethylenetetramine,
and polyethyleneimine.
[0082] In another embodiment, the nitrogen containing group may be
derived from an aromatic amine. Aromatic amines include those which
can be represented by the general structure NH.sub.2--Ar or
T-NH--Ar, where T may be alkyl or aromatic, Ar is an aromatic
group, including nitrogen-containing aromatic groups and Ar groups
including any of the following structures:
##STR00003##
[0083] as well as multiple non-condensed or linked aromatic rings.
In these and related structures, R.sup.5, R.sup.6, and R.sup.7 can
be independently selected from, among other groups disclosed
herein, --H, --C.sub.1-18 alkyl groups, nitro groups, --NH--Ar,
--N.dbd.N--Ar, --NH--CO--Ar, --OOC--Ar, --OOC--C.sub.1-18 alkyl,
--COO--C.sub.1-18 alkyl, --OH,
--O--(CH.sub.2CH.sub.2--O).sub.nC.sub.1-18 alkyl groups, and
--O--(CH.sub.2CH.sub.2O).sub.nAr (where n is 0 to 10).
[0084] Exemplary aromatic amines include those amines wherein a
carbon atom of the aromatic ring structure is attached directly to
the amino nitrogen. The aromatic amines may be monoamines or
polyamines. The aromatic ring may be a mononuclear aromatic ring
(i.e., one derived from benzene) but can include fused aromatic
rings, especially those derived from naphthalene. Examples of
aromatic amines include aniline, N-alkylanilines such as
N-methylaniline and N-butylaniline, di-(para-methylphenyl)amine,
4-am inodiphenylamine, N,N-dimethylphenylenediamine, naphthylamine,
4-(4-nitrophenyl-azo)aniline (disperse orange 3), sulfamethazine,
4-phenoxyaniline, 3-nitroaniline, 4-aminoacetanilide
(N-(4-aminophenyl)acetamide)), 4-amino-2-hydroxy-benzoic acid
phenyl ester (phenyl amino salicylate),
N-(4-amino-phenyl)-benzamide, various benzylamines, such as
2,5-dimethoxybenzylamine, 4-phenylazoaniline, and combinations and
substituted versions of these. Other examples include
para-ethoxyaniline, para-dodecylaniline, cyclohexyl-substituted
naphthylamine, and thienyl-substituted aniline. Examples of other
suitable aromatic amines include amino-substituted aromatic
compounds and amines in which the amine nitrogen is a part of an
aromatic ring, such as 3-aminoquinoline, 5-aminoquinoline, and
8-aminoquinoline. Also included are aromatic amines, such as
2-aminobenzimidazole, which contains one secondary amino group
attached directly to the aromatic ring and a primary amino group
attached to the imidazole ring. Other amines include
N-(4-anilinophenyl)-3-aminobutanamide, and 3-amino propyl
imidazole, and 2,5-dimethoxybenzylamine.
[0085] Additional aromatic amines and related compounds are
disclosed in U.S. Pat. Nos. 6,107,257 and 6,107,258. Examples of
these include aminocarbazoles, benzoimidazoles, aminoindoles,
aminopyrroles, amino-indazolinones, am inoperimidines,
mercaptotriazoles, am inophenothiazines, aminopyridines,
aminopyrazines, aminopyrimidines, pyridines, pyrazines,
pyrimidines, aminothiadiazoles, aminothiothiadiazoles, and
aminobenzotriazoles. Other suitable amines include
3-amino-N-(4-anilinophenyl)-N-isopropyl butanamide, and
N-(4-anilinophenyl)-3-{(3-aminopropyl)-(cocoalkyl)amino}
butanamide. Other aromatic amines which can be used include various
aromatic amine dye intermediates containing multiple aromatic rings
linked by, for example, amide structures. Examples include
materials of the general structure:
##STR00004##
[0086] and isomeric variations thereof, where R.sup.8 and R.sup.9
are independently alkyl or alkoxy groups such as methyl, methoxy,
or ethoxy.
[0087] In one instance, R.sup.8 and R.sup.9 are both --OCH.sub.3
and the material is known as Fast Blue RR [CAS#6268-05-9]. In
another instance, R.sup.9 is --OCH.sub.3 and R.sup.8 is --CH.sub.3,
and the material is known as Fast Violet B [99-21-8]. When both
R.sup.8 and R.sup.9 are ethoxy, the material is known as Fast Blue
BB [120-00-3]. U.S. Pat. No. 5,744,429 discloses other aromatic
amine compounds useful herein, particularly
aminoalkylphenothiazines. N-aromatic substituted acid amide
compounds, such as those disclosed in U.S. Pub. No. 2003/0030033,
may also be used herein. Suitable aromatic amines include those in
which the amine nitrogen is a substituent on an aromatic carboxylic
compound, that is, the nitrogen is not sp.sup.2 hybridized within
an aromatic ring.
[0088] The aromatic amine may have an N--H group capable of
condensing with the pendent carbonyl-containing group. Certain
aromatic amines are commonly used as antioxidants. Examples of
these are alkylated diphenylamines, such as nonyldiphenylamine and
dinonyldiphenylamine. To the extent that these materials will
condense with the carboxylic functionality of the polymer chain,
they are also suitable for use herein. However, it is believed that
the two aromatic groups attached to the amine nitrogen reduce its
reactivity. Thus, suitable amines include those having a primary
nitrogen atom (--NH.sub.2) or a secondary nitrogen atom in which
one of the hydrocarbyl substituents is a relatively short chain
alkyl group, e.g., methyl. Among such aromatic amines are
4-phenylazoaniline, 4-aminodiphenylamine, 2-aminobenzimidazole, and
N,N-dimethylphenylenediamine. Some of these and other aromatic
amines may also impart antioxidant performance to the copolymers,
in addition to dispersancy and other properties.
[0089] In one embodiment, the amine component of the copolymer
further includes an amine having at least two N--H groups capable
of condensing with the carboxylic functionality of the copolymer.
This material is referred to hereinafter as a "linking amine" as it
can be employed to link together two of the copolymers containing
the carboxylic acid functionality. It has been observed that higher
molecular weight materials may provide improved performance, and
this is one method to increase the material's molecular weight. The
linking amine can be either an aliphatic amine or an aromatic
amine; if it is an aromatic amine, it is considered to be in
addition to and a distinct element from the aromatic amine
described above, which typically will have only one condensable or
reactive NH group, in order to avoid excessive crosslinking of the
copolymer chains. Examples of such linking amines include
ethylenediamine, phenylenediamine, and 2,4-diaminotoluene; others
include propylenediamine, hexamethylenediamine, and other,
.omega.-polymethylenediamines. The amount of reactive functionality
on such a linking amine can be reduced, if desired, by reaction
with less than a stoichiometric amount of a blocking material such
as a hydrocarbyl-substituted succinic anhydride.
[0090] In one embodiment, the exemplary copolymer provides for
oxidation control. Typically, the copolymer with oxidation control
contains an incorporated residue of an amine-containing compound
such as morpholines, pyrrolidinones, imidazolidinones, amino amides
(such as acetamides), .beta.-alanine alkyl esters, and mixtures
thereof. Examples of suitable nitrogen-containing compounds include
3-morpholin-4-yl-propylamine, 3-morpholin-4-yl-ethylamine,
.beta.-alanine alkyl esters (typically alkyl esters have 1 to 30,
or 6 to 20 carbon atoms), or mixtures thereof.
[0091] In one embodiment, the compounds based on imidazolidinones,
cyclic carbamates or pyrrolidinones may be derived from a compound
of general structure:
##STR00005##
wherein
[0092] X=--OH or NH.sub.2;
[0093] Hy'' is hydrogen, or a hydrocarbyl group (typically alkyl,
or C.sub.1-4--, or C.sub.2-- alkyl);
[0094] Hy is a hydrocarbylene group (typically alkylene, or
C.sub.1-4--, or C.sub.2-- alkylene);
[0095] Q=>NH, >NR, >CH.sub.2, >CHR, >CR.sub.2, or
--O-- (typically >NH, or >NR) and R is C.sub.1 alkyl.
[0096] In one embodiment, the imidazolidinone includes
1-(2-amino-ethyl)-imidazolidin-2-one (may also be called
aminoethylethyleneurea), 1-(3-amino-propyl)-imidazolidin-2-one,
1-(2-hydroxy-ethyl)-imidazolidin-2-one,
1-(3-amino-propyl)-pyrrolidin-2-one,
1-(3-amino-ethyl)-pyrrolidin-2-one, or mixtures thereof.
[0097] In one embodiment, the amino amide includes an acetamide,
which may be represented by the general structure:
##STR00006##
[0098] wherein:
[0099] Hy is a hydrocarbylene group (typically alkylene, or
C.sub.1-4--, or C.sub.2-- alkylene); and
[0100] Hy' is a hydrocarbyl group (typically alkyl, or C.sub.1-4--,
or methyl).
[0101] Examples of a suitable acetamide include
N-(2-amino-ethyl)-acetamide, or N-(2-amino-propyl)-acetamide.
[0102] In one embodiment, the .beta.-alanine alkyl esters may be
represented by the general structure:
##STR00007##
[0103] wherein:
[0104] R.sup.10 is an alkyl group having 1 to 30, or 6 to 20 carbon
atoms.
[0105] Examples of suitable .beta.-alanine alkyl esters include
.beta.-alanine octyl ester, .beta.-alanine decyl ester,
.beta.-alanine 2-ethylhexyl ester, .beta.-alanine dodecyl ester,
.beta.-alanine tetradecyl ester, or .beta.-alanine hexadecyl
ester.
[0106] In one embodiment, the copolymer may be reacted with an
amine selected from the group consisting of
1-(2-amino-ethyl)-imidazolidin-2-one, 4-(3-aminopropyl)morpholine,
3-(dimethylamino)-1-propylamine, N-phenyl-p-phenylenediamine,
N-(3-aminopropyl)-2-pyrrolidinone, aminoethyl acetamide,
.beta.-alanine methyl ester, 1-(3-aminopropyl) imidazole, and
mixtures thereof.
[0107] In one embodiment, the copolymer may be reacted with an
amine-containing compound selected from morpholines,
imidazolidinones, and mixtures thereof.
[0108] In one embodiment, the nitrogen-containing compound is
selected from 1-(2-aminoethyl)imidazolidinone,
4-(3-aminopropyl)morpholine, 3-(dimethylamino)-1-propylamine,
N-phenyl-p-phenylenediamine, N-(3-aminopropyl)-2-pyrrolidinone,
aminoethyl acetamide, .beta.-alanine methyl ester,
1-(3-aminopropyl) imidazole, and combinations thereof.
[0109] In one embodiment, the nitrogen-containing compound is a
non-dispersing nitrogen compound having only a single reactive
nitrogen group. Reactive nitrogen groups are primary or secondary
nitrogen groups, i.e., nitrogen groups having at least one hydrogen
atom on the nitrogen. For example, the nitrogen-containing compound
is substantially free (i.e., no more than 2.5 mol %, or up to 0.1
mol %, or 0 mol %) of dispersing nitrogen-containing compounds,
i.e., those having at least a second reactive nitrogen group, i.e.,
more reactive nitrogen group(s) than take part in the reaction with
the esterified copolymer, which leaves reactive nitrogen groups on
the resulting copolymer.
[0110] The ester group and/or nitrogen containing group may be
sufficient to provide 0.01 wt. % to 1.5 wt. % (or 0.02 wt. % to
0.75 wt. %, or 0.04 wt. % to 0.25 wt. %, or 0.2 wt. % to 0.8 wt. %)
nitrogen to the copolymer.
[0111] I. Preparation of the Copolymer
[0112] A. Formation of the Copolymer Backbone
[0113] The copolymer may optionally be prepared in the presence of
a free radical initiator, solvent, or mixtures thereof. It will be
appreciated that altering the amount of initiator can alter the
number average molecular weight of the exemplary copolymer.
[0114] The copolymer backbone may be prepared by reacting the
carboxylic acid monomer with the vinyl aliphatic monomer.
[0115] The solvent can be a liquid organic diluent. Generally, the
solvent has a boiling point that is high enough to provide the
required reaction temperature. Illustrative diluents include
toluene, t-butyl benzene, benzene, xylene, chlorobenzene, various
petroleum fractions boiling above 125.degree. C., and mixtures
thereof.
[0116] The free radical initiator can include one or more peroxy
compounds, such as peroxides, hydroperoxides, and azo compounds
which decompose thermally to provide free radicals. Other suitable
examples are described in J. Brandrup and E. H. Immergut, Editor,
"Polymer Handbook", 2nd edition, John Wiley and Sons, New York
(1975), pages II-1 to II-40. Examples of a free radical initiator
include those derived from a free radical-generating reagent, and
examples include benzoyl peroxide, t-butyl perbenzoate, t-butyl
metachloroperbenzoate, t-butyl peroxide,
sec-butylperoxydicarbonate, azobisisobutyronitrile, t-butyl
peroxide, t-butyl hydroperoxide, t-amyl peroxide, cumyl peroxide,
t-butyl peroctoate, t-butyl-m-chloroperbenzoate,
azobisisovaleronitrile, and mixtures thereof. In one embodiment,
the free radical generating reagent is t-butyl peroxide, t-butyl
hydroperoxide, t-amyl peroxide, cumyl peroxide, t-butyl peroctoate,
t-butyl-m-chloroperbenzoate, azobisisovaleronitrile, or mixtures
thereof. Commercially available free radical initiators include
classes of compound sold under the trademark Trigonox.RTM.-21 from
Akzo Nobel.
[0117] An exemplary backbone polymer can be formed as follows:
alpha-olefin is reacted with maleic anhydride in the presence of
radical initiator and optionally in the presence of solvent. A
solvent such as toluene can be used to lower backbone length by
diluting the monomer concentration and through chain transfer to
the benzylic protons. Scheme 1 shows an example where the
alpha-olefin is 1-dodecene, the initiator is tert-butyl
peroxy-2-ethylhexanoate (sold under the tradename Trigonox 21S by
Akzo Nobel), and the solvent is toluene.
##STR00008##
[0118] where n and m are independently at least 1, such as an
integer from 1 to 10, or from 1 to 5, or from 1 to 3 in each
segment of the copolymer (denoted by the two asterisks). As will be
appreciated, the resulting backbone copolymer can have random
variation of n and m.
[0119] B. Esterification
[0120] Esterification (or transesterification, when the copolymer
already contains ester groups and those of a different type are
desired) of the exemplary backbone copolymer can be accomplished by
heating any of the copolymers described above and one or more
desired alcohols and/or alkoxylates under conditions typical for
effecting esterification. Such conditions include, for example, a
temperature of at least 80.degree. C., such as up to 150.degree. C.
or higher, provided that the temperature is maintained below the
lowest decomposition temperature of any .degree. component of the
reaction mixture or products thereof. Water or lower alcohol is
normally removed as the esterification proceeds. These conditions
may optionally include the use of a substantially inert, normally
liquid, organic solvent or diluent such as mineral oil, toluene,
benzene, xylene, or the like, and an esterification catalyst such
as one or more of toluene sulfonic acid, sulfuric acid, aluminum
chloride, boron trifluoride-triethylamine, methane sulfonic acid,
trifluoro-methanesulfonic acid, hydrochloric acid, ammonium
sulfate, and phosphoric acid. Further details of conducting the
esterification can be found in U.S. Pat. No. 6,544,935, at column
11.
[0121] In one embodiment, at least 75% of, or in certain
embodiments at least 80%, or at least 90%, or 95% to 98% of the
carboxy functions of the copolymer are esterified. Most or all of
the remaining carboxy functions, which are un-converted to ester
groups, will subsequently be converted to nitrogen-containing
groups. An excess of alcohols and/or alkoxylates over the
stoichiometric requirement for complete esterification of the
carboxy functions may be used in the esterification process
provided the ester content of the polymer remains in an appropriate
range, e.g., within the 80 to 85% range. The excess of alcohols and
alkoxylates or unreacted alcohols and alkoxylates need not be
removed as such alcohols and alkoxylates can serve, for example, as
diluent or solvent in the exemplary lubricating composition.
Similarly, optional reaction media, e.g., toluene, need not be
removed as they can similarly serve as diluent or solvent in the
lubricating composition. In other embodiments, unreacted alcohols,
alkoxylates and diluents are removed by well-known techniques, such
as distillation.
[0122] Scheme 2 illustrates the case when the backbone copolymer of
Scheme 1 is esterified. Esterification solubilizes the copolymer in
oil and also improves the low temperature viscosity and improves
the viscosity index of the lubricating composition including the
esterified copolymer. The example shown uses a linear, primary
C.sub.8-10 alcohol mixture (available from Sasol under the trade
name Alfol 810.TM.) and 2-hexyl decan-1-ol (available from Sasol
under the trade name Isofol 16.TM.), in methanesulfonic acid. R and
R' are independently selected from linear C.sub.8-10 alkyl and
2-hexyl decyl.
##STR00009##
[0123] C. Formation of Nitrogen-Containing Groups on the Copolymer
Backbone
[0124] The nitrogen-containing compound may be directly reacted
onto the copolymer backbone by grafting of the amine, or other
nitrogen-containing functional group, onto the copolymer backbone
either (i) in a solution using a solvent, or (ii) under reactive
extrusion conditions in the presence or absence of solvent. The
amine-functional monomer may be grafted onto the copolymer backbone
in multiple ways. In one embodiment, the grafting takes place by a
thermal process via an "ene" reaction. In one embodiment, the
grafting takes place by a Friedel-Crafts acylating reaction. In
another embodiment, the grafting is carried out in solution or
solid form through a free radical initiator. Solution grafting is a
well-known method for producing grafted copolymers. In such a
process, reagents are introduced either neat or as solutions in
appropriate solvents. The desired copolymer product may then be
separated from the reaction solvents and/or impurities by
appropriate purification steps.
[0125] In one embodiment, the nitrogen-containing compound may be
directly reacted onto the copolymer backbone by free radical
catalyzed grafting of the copolymer in a solvent, such as an
organic solvent such as benzene, t-butyl benzene, toluene, xylene,
hexane, or a combination thereof. The reaction may be carried out
at an elevated temperature in the range of 100.degree. C. to
250.degree. C. or 120.degree. C. to 230.degree. C., or 160.degree.
C. to 200.degree. C., e.g., above 160.degree. C., in a solvent,
such as a mineral lubricating oil solution containing, e.g., 1 to
50, or 5 to 40 wt. %, based on the initial total oil solution of
the copolymer and optionally under an inert environment.
[0126] By way of example, Scheme 3 exemplifies the consumption of
residual anhydride groups in the backbone copolymer produced by
Scheme 1, following the esterification in Scheme 2, using a primary
amine(s). The functional group R in Scheme 3 can be selected to
improve dispersancy.
##STR00010##
[0127] In one embodiment, the amine can have more than one nitrogen
and can be selected from aliphatic amines and aromatic amines such
that the R group attached to the amine that reacts with the
carboxylic acid monomer contains at least one nitrogen atom,
optionally substituted with hydrocarbyl groups. The hydrocarbyl
groups can be selected from aliphatic, aromatic, cyclic, and
acyclic hydrocarbyl groups. As the amine, one or more of the
following may be used: 1-(2-amino-ethyl)-imidazolidin-2-one,
4-(3-aminopropyl)morpholine, 3-(dimethylamino)-1-propylamine,
N-phenyl-p-phenylenediamine, N-(3-aminopropyl)-2-pyrrolidinone,
aminoethyl acetamide, .beta.-alanine methyl ester, and
1-(3-aminopropyl) imidazole.
[0128] In another embodiment, the nitrogen-containing compound may
be a monomer that can polymerize with both the vinyl aliphatic
monomer and the carboxylic acid monomer such that the
nitrogen-containing monomer is incorporated into the backbone. For
example, a free radical catalyzed reaction is employed.
[0129] II. Lubricating Composition
[0130] In one embodiment, a lubricating composition includes an oil
of lubricating viscosity and the exemplary copolymer comprising
units derived from a vinyl aliphatic monomer and a carboxylic acid
monomer as described above, which may have been esterified with a
primary alcohol and may have been reacted with a
nitrogen-containing compound, as described above. The lubricating
composition may include no more than 2.5 wt. % of dispersants,
other than the exemplary copolymer, for dispersing oxidation
products generated during use of the lubricating composition in a
mechanical device.
[0131] The lubricating composition may include the oil of
lubricating viscosity as a minor or major component thereof, such
as at least 5 wt. %, or at least 20 wt. %, or at least 30 wt. %, or
at least 40 wt. % of the lubricating composition. The lubricating
composition suitable for use in a driveline system may include the
oil of lubricating viscosity in an amount of at least 5 wt. % or at
least 20 wt. % or at least 30 wt. % of the lubricating composition.
In one embodiment, the oil of lubricating viscosity is no more than
60 wt % of the lubricating composition.
[0132] In one embodiment, the esterified copolymer is 5-95 wt. %,
or 10-60 wt. %, or 30-60 wt. %, or 40-50 wt. % of the lubricating
composition. Example lubricating compositions include 5-30 wt. %,
or 5-20 wt. %, or 5-15 wt. %, or 5-10 wt. %, or 20-40 wt. % of the
exemplary copolymer.
[0133] A ratio of the weight of the oil of lubricating viscosity to
the weight of the exemplary copolymer in the lubricating
composition may be from 5:95 to 95:5, or from 40:60 to 80:20. A
ratio of the weight of the exemplary copolymer to the weight of the
dispersants in the lubricating composition may be from 98:2 to
100:0, or from 99:1 to 100:0, or from 99.5:0.5 to 100:0.
[0134] In some embodiments, a lubricant concentrate may be admixed
with a base oil to form the lubricating composition. The lubricant
concentrate may be formulated as for the lubricating composition
but may include the oil of lubricating viscosity in a lesser amount
than in the fully formulated lubricating composition or may contain
no oil of lubricating viscosity. The lubricant concentrate may be
combined with additional oil to form, in whole or in part, a
finished lubricant, and thus the ratio of the copolymer to the oil
of lubricating viscosity and/or to diluent oil include the ranges
of 1:99 to 99:1 by weight, or from 80:20 to 10:90 by weight.
[0135] The lubricating composition may include one or more
additives in addition to the exemplary copolymer and oil of
lubricating viscosity, such as one or more performance additives,
such as other viscosity index improvers, extreme pressure agents,
antiwear agents, antiscuffing agents, corrosion inhibitors, and the
like.
[0136] A. Oil of Lubricating Viscosity
[0137] Suitable oils of lubricating viscosity include natural and
synthetic oils, oils derived from hydrocracking, hydrogenation, and
hydrofinishing, unrefined, refined and re-refined oils, and
mixtures thereof.
[0138] Unrefined oils are those obtained directly from a natural or
synthetic source generally without (or with little) further
purification treatment.
[0139] Refined oils are similar to the unrefined oils except they
have been further treated in one or more purification steps to
improve one or more properties. Purification techniques are known
in the art and include solvent extraction, secondary distillation,
acid or base extraction, filtration, percolation and the like.
[0140] Re-refined oils are also known as reclaimed or reprocessed
oils, and are obtained by processes similar to those used to obtain
refined oils and often are additionally processed by techniques
directed to removal of spent additives and oil breakdown
products.
[0141] Natural oils useful as oils of lubricating viscosity include
animal oils or vegetable oils (e.g., castor oil or lard oil),
mineral lubricating oils, such as liquid petroleum oils and
solvent-treated or acid-treated mineral lubricating oils of the
paraffinic, naphthenic or mixed paraffinic-naphthenic types, and
oils derived from coal or shale or mixtures thereof.
[0142] Synthetic lubricating oils useful as oils of lubricating
viscosity include hydrocarbon oils, such as polymerized and
copolymerized olefins (e.g., polybutylenes, polypropylenes,
propyleneisobutylene copolymers); poly(l-hexenes), poly(1-octenes),
poly(1-decenes), and mixtures thereof; alkyl-benzenes (e.g.,
dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,
di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls,
terphenyls, alkylated polyphenyls); alkylated diphenyl ethers and
alkylated diphenyl sulfides and the derivatives, analogs and
homologs thereof, and mixtures thereof.
[0143] Other synthetic lubricating oils include polyol esters (such
as Priolube.RTM. 3970), diesters, liquid esters of
phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl
phosphate, and the diethyl ester of decane phosphonic acid), or
polymeric tetrahydrofurans. Synthetic oils may be produced by
Fischer-Tropsch reactions and typically may be hydroisomerized
Fischer-Tropsch hydrocarbons or waxes. In one embodiment, oils may
be prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure
as well as other gas-to-liquid (GTL) oils.
[0144] Oils of lubricating viscosity may also be defined as
specified in the American Petroleum Institute (API) Base Oil
Interchangeability Guidelines. The five base oil groups are as
follows: Group I (sulfur content >0.03 wt. %, and/or <90 wt.
% saturates, viscosity index 80-120); Group II (sulfur content
.ltoreq.0.03 wt. %, and .gtoreq.90 wt. % saturates, viscosity index
80-120); Group III (sulfur content .ltoreq.0.03 wt. %, and
.gtoreq.90 wt. % saturates, viscosity index .gtoreq.120); Group IV
(all polyalphaolefins (PAOs)); and Group V (all others not included
in Groups I, II, III, or IV). The exemplary oil of lubricating
viscosity includes an API Group Group II, Group III, Group IV,
Group V oil, or mixtures thereof. In some embodiments, the oil of
lubricating viscosity is an API Group I, Group II, Group III, or
Group IV oil, or mixtures thereof. In some embodiments, the oil of
lubricating viscosity is an API Group I, Group II, or Group III
oil, or mixtures thereof.
[0145] B. Performance Additives
[0146] The lubricating composition described herein optionally
further includes one or more performance additives. The performance
additives, other than the exemplary copolymer, may include at least
one of metal deactivators, detergents, dispersants (but only in
minor amounts), viscosity index improvers, friction modifiers,
corrosion inhibitors, antiwear agents, extreme pressure agents,
antiscuffing agents, antioxidants, foam inhibitors, demulsifiers,
pour point depressants, seal swelling agents, and mixtures thereof.
Typically, the fully-formulated lubricating composition (or "oil")
will contain one or more of these performance additives. Suitable
amounts of these additives in the exemplary lubricating composition
are given below. These amounts are all expressed on an oil-free
basis, i.e., exclusive of any diluent.
[0147] 1. Dispersants
[0148] As noted above, the exemplary fully-formulated lubricating
composition is free or substantially free of dispersants for
dispersing oxidation products, other than the exemplary esterified
copolymer. Examples of dispersants which may be totally absent from
the lubricating composition, or present in only limited amounts, as
specified above, are given below.
[0149] Exemplary dispersants are often known as ashless-type
dispersants because, prior to mixing in a lubricating oil
composition, they do not contain ash-forming metals and they do not
normally contribute any ash forming metals when added to a
lubricant and polymeric dispersants. Ashless type dispersants are
characterized by a polar group attached to a relatively high
molecular weight hydrocarbon chain. Typical ashless dispersants
include succinimides, phosphonates, and combinations thereof.
[0150] Exemplary succinimides include N-substituted long chain
alkenyl succinimides. Examples of N-substituted long chain alkenyl
succinimides include poly(C3-C6 alkylene) succinimides, such as
polyisobutylene succinimides, with a number average molecular
weight of the polyisobutylene substituent in the range of 350 to
5000, or 500 to 3000, or 1000-2500, or from 1300 to 2500.
[0151] Exemplary conventional and high vinylidine polyisobutylenes
which may be used in forming the succinimide dispersant are
disclosed, for example, in U.S. Pat. Nos. 3,215,707; 3,231,587;
3,515,669; 3,579,450; 3,912,764; 4,605,808; 4,152,499; 5,071,919;
5,137,980; 5,286,823; 5,254,649
[0152] Ethylene/alpha olefin copolymers which may be used in
forming the succinimide dispersant are disclosed, for example, in
U.S. Pat. Nos. 5,498,809; 5,663,130; 5,705,577; 5,814,715;
6,022,929; and 6,030,930.
[0153] Other exemplary dispersants can be derived from
polyisobutylene, an amine and zinc oxide to form a polyisobutylene
succinimide complex with zinc.
[0154] Another class of ashless dispersant is acylated polyalkylene
polyamines of the type described in U.S. Pat. No. 5,330,667.
[0155] Another class of ashless dispersants is Mannich bases.
Mannich dispersants are the reaction products of alkyl phenols with
aldehydes (especially formaldehyde) and amines (especially
polyalkylene polyamines). The alkyl group typically contains at
least 30 carbon atoms.
[0156] Various methods for the preparation of succinimide
dispersants are known. For example the exemplary dispersant can be
produced by reaction of a C3-C6 polyalkylene (e.g., polypropylene,
polyisobutylene, polypentylene, polyheptylene) or derivative
thereof (e.g., a chlorinated derivative) with a mono- or
.alpha.,.beta. unsaturated-dicarboxylic acid or anhydride thereof
(such as maleic anhydride or succinic anhydride) to produce an
acylated C3-C6 polyalkylene compound, which is reacted with an
amine, such as a primary amine or a polyamine, such as a
polyethylene amine, to produce the dispersant.
[0157] Some of the following references are directed toward making
an acylated C3-C6 polyalkylene compound suited to use in forming
succinimide dispersants while others disclose the making of a
succinimide dispersant itself. Two step methods are described, for
example, in U.S. Pat. Nos. 3,087,936; 3,172,892; and 3,272,746; one
step methods are described in U.S. Pat. Nos. 3,215,707, 3,231,587;
3,912,764; 4,110,349; and 4,234,435; thermal methods for forming
succinimides of tetraethylene pentamine are described in U.S. Pat.
Nos. 3,361,673 and 3,401,118; methods for forming succinimides of
halogenated alpha-olefin polymers are described in U.S. Pat. No.
5,266,223; free radical methods are described in U.S. Pat. Nos.
4,505,834; 4,749,505, and 4,863,623; grafting methods are described
in U.S. Pat. Nos. 4,340,689; 4,670,515; 4,948,842 and
5,075,383.
[0158] The dispersants may also be post-treated by conventional
methods by a reaction with any of a variety of agents. Among these
are boron compounds (such as boric acid), urea, thiourea,
dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones,
carboxylic acids such as terephthalic acid, hydrocarbon-substituted
succinic anhydrides, maleic anhydride, nitriles, epoxides, and
phosphorus compounds. In one embodiment, the post-treated
dispersant is borated.
[0159] While the exemplary lubricating composition may be
dispersant-free, in one embodiment, to the extent that a dispersant
is in fact present, only nitrogen-containing C3-C6 acylated
polyalkylene compounds are used. In particular, succinimide
dispersants derived from the reaction of an acylated C3-C6
polyalkylene compound with an amine to form a succinic acid
anhydride, are employed. It has been found that small amounts of
such succinimide dispersants can be used without impacting the spot
rating unduly. The exemplary copolymer, however, allows the amount
of such dispersants to be minimized or avoided altogether, due to
the advantageous effect of the copolymer on dispersion of oxidation
products.
[0160] In one embodiment, the dispersant is present in the
lubricating composition, e.g., at 0.01-2.5 wt. %, or at 0.01-2 wt.
%, or at 0.01-1.75 wt. %, or at 0.01-1.5 wt. %), or at 0.5-2.5 wt.
%, or at 0.5-1.75 wt. %, or at 0.5-1.5 wt. %, and consists
essentially of a nitrogen-containing dispersant or dispersants
derived from an acylated C3-C6 polyalkylene compound. By consists
essentially of, it is meant that no more than 0.2 wt. %, or no more
than 0.1 wt. %, no more than 0.01 wt. % of the lubricating
composition is dispersants other than these. A gear oil produced
with such low levels of dispersant is still highly effective due to
the presence of the exemplary esterified copolymer.
[0161] In one embodiment, the exemplary copolymer is substantially
free of nitrogen, as defined above, and the lubricating composition
contains no more than 1.75 wt. % dispersant, other than the
exemplary copolymer.
[0162] 2. Detergents
[0163] The lubricating composition optionally further includes
known neutral or overbased detergents, i.e., ones prepared by
conventional processes known in the art. Suitable detergents
include phenates, sulfur containing phenates, sulfonates,
salixarates, salicylates, carboxylic acid, phosphorus acids, alkyl
phenols, sulfur coupled alkyl phenol compounds, and saligenins. The
detergent may be present at 0 wt. % to 1 wt. %, or 0.01 wt. % to 1
wt. %, or 0.05 wt. % to 0.75 wt. %, or 0.1 wt. % to 0.75 wt. % of
the lubricating composition.
[0164] 3. Antioxidants
[0165] Antioxidant compounds useful herein as oxidation inhibitors
include sulfurized olefins, diphenylamines,
phenyl-alpha-naphthylamines, hindered phenols, molybdenum
dithiocarbamates, and mixtures and derivatives thereof. Antioxidant
compounds may be used alone or in combination.
[0166] Exemplary diphenylamines include diarylamines, such as
alkylated diphenylamines.
[0167] Exemplary hindered phenol antioxidants may contain a
secondary butyl and/or a tertiary butyl group as a sterically
hindering group. The phenol group is often further substituted with
a hydrocarbyl group and/or a bridging group linking to a second
aromatic group. Examples of suitable hindered phenol antioxidants
include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol,
4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol,
4-butyl-2,6-di-tert-butylphenol, 4-dodecyl-2,6-di-tert-butylphenol,
and mixtures thereof. In one embodiment, the hindered phenol
antioxidant is an ester and may include, e.g., Irganox.TM. L-135
from Ciba. Suitable examples of molybdenum dithiocarbamates which
may be used as an antioxidant include commercial materials sold
under the trade names Vanlube 822.TM. and Molyvan.TM. A from R. T.
Vanderbilt Co., Ltd., and Adeka Sakura-Lube.TM. S-100, S-165 and
S-600 from Asahi Denka Kogyo K. K, and mixtures thereof.
[0168] The antioxidant(s) may be present at up to 2 wt. %, or up to
1.5 wt. %, or up to 1.0 wt. %, or up to 0.7 wt. % of the
lubricating composition, such as at least 0.001 wt. .degree. A), or
at least 0.01 wt. %, or at least 0.1 wt. % of the lubricating
composition.
[0169] 4. Viscosity Index Improvers
[0170] Viscosity index improvers, other than the exemplary
copolymer, may include hydrogenated styrene-butadiene rubbers,
ethylene-propylene copolymers, hydrogenated styrene-isoprene
polymers, hydrogenated diene polymers, polyalkyl styrenes,
polyolefins, polyalkyl (meth)acrylates, and mixtures thereof. In
one embodiment, the viscosity index improver (polymeric thickener)
is a poly(meth)acrylate.
[0171] 5. Antiwear Agents
[0172] The lubricating composition optionally further includes at
least one antiwear agent.
[0173] Examples of suitable antiwear agents include oil soluble
amine salts of phosphorus compounds, sulfurized olefins, metal
dihydrocarbyldithiophosphates (such as zinc
dialkyldithiophosphates), thiocarbamate-containing compounds, such
as thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers,
alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl)
disulfides.
[0174] In one embodiment, the oil soluble phosphorus amine salt
antiwear agent includes an amine salt of a phosphorus acid ester or
mixtures thereof. The amine salt of a phosphorus acid ester
includes phosphoric acid esters and amine salts thereof;
dialkyldithiophosphoric acid esters and amine salts thereof; amine
salts of phosphites; and amine salts of phosphorus-containing
carboxylic esters, ethers, and amides; and mixtures thereof. The
amine salt of a phosphorus acid ester may be used alone or in
combination.
[0175] In one embodiment, the oil soluble phosphorus amine salt
includes partial amine salt-partial metal salt compounds or
mixtures thereof. In one embodiment, the phosphorus compound
further includes a sulfur atom in the molecule. In one embodiment,
the amine salt of the phosphorus compound is ashless, i.e.,
metal-free (prior to being mixed with other components).
[0176] The amines which may be suitable for use as the amine salt
include primary amines, secondary amines, tertiary amines, and
mixtures thereof. The amines include those with at least one
hydrocarbyl group, or, in certain embodiments, two or three
hydrocarbyl groups. The hydrocarbyl groups may contain 2 to 30
carbon atoms, or in other embodiments 8 to 26, or 10 to 20, or 13
to 19 carbon atoms.
[0177] Primary amines include ethylamine, propylamine, butylamine,
2-ethylhexylamine, octylamine, and dodecylamine, as well as such
fatty amines as n-octylamine, n-decylamine, n-dodecylamine,
n-tetradecylamine, n-hexadecylamine, n-octadecylamine and
oleylamine. Other useful fatty amines include commercially
available fatty amines such as "Armeen.RTM." amines (products
available from Akzo Chemicals, Chicago, Ill.), such as Armeen C,
Armeen O, Armeen OL, Armeen T, Armeen HT, Armeen S and Armeen SD,
wherein the letter designation relates to the fatty group, such as
coco, oleyl, tallow, or stearyl groups.
[0178] Examples of suitable secondary amines include dimethylamine,
diethylamine, dipropylamine, dibutylamine, diamylamine,
dihexylamine, diheptylamine, methylethylamine, ethylbutylamine and
ethylamylamine. The secondary amines may be cyclic amines such as
piperidine, piperazine and morpholine.
[0179] The amine may also be a tertiary-aliphatic primary amine.
The aliphatic group in this case may be an alkyl group containing 2
to 30, or 6 to 26, or 8 to 24 carbon atoms. Tertiary alkyl amines
include monoamines such as tert-butylamine, tert-hexylamine,
1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine,
tert-dodecylamine, tert-tetradecylamine, tert-hexadecylamine,
tert-octadecylamine, tert-tetracosanyiamine, and
tert-octacosanylamine.
[0180] In one embodiment, the phosphorus acid amine salt includes
an amine with C.sub.11 to C.sub.14 tertiary alkyl primary groups or
mixtures thereof. In one embodiment, the phosphorus acid amine salt
includes an amine with C.sub.14 to C.sub.18 tertiary alkyl primary
amines or mixtures thereof. In one embodiment, the phosphorus acid
amine salt includes an amine with C.sub.18 to C.sub.22 tertiary
alkyl primary amines or mixtures thereof.
[0181] Mixtures of amines may also be used herein. In one
embodiment a useful mixture of amines is "Primene.RTM. 81R" and
"Primene.RTM. JMT." Primene.RTM. 81R and Primene.RTM. JMT (both
produced and sold by Rohm & Haas) are mixtures of C.sub.ii to
C.sub.14 tertiary alkyl primary amines and C.sub.18 to C.sub.22
tertiary alkyl primary amines respectively.
[0182] In one embodiment, oil soluble amine salts of phosphorus
compounds include a sulfur-free amine salt of a
phosphorus-containing compound which is obtained/obtainable by a
process comprising: reacting an amine with either (i) a
hydroxy-substituted di-ester of phosphoric acid, or (ii) a
phosphorylated hydroxy-substituted di- or tri-ester of phosphoric
acid. A more detailed description of compounds of this type is
disclosed in US Pub. No. 2008/0182770.
[0183] In one embodiment, the hydrocarbyl amine salt of an
alkylphosphoric acid ester is the reaction product of a C.sub.14 to
C.sub.18 alkylated phosphoric acid with the Primene 81R.TM. product
(produced and sold by Rohm & Haas) which is a mixture of
C.sub.11 to C.sub.14 tertiary alkyl primary amines.
[0184] Examples of hydrocarbyl amine salts of
dialkyldithiophosphoric acid esters include the reaction product(s)
of isopropyl, methyl-amyl (4-methyl-2-pentyl or mixtures thereof),
2-ethylhexyl, heptyl, octyl or nonyl dithiophosphoric acids with
ethylene diamine, morpholine, or Primene 81R.TM., and mixtures
thereof.
[0185] In one embodiment, the dithiophosphoric acid may be reacted
with an epoxide or a glycol. This reaction product is further
reacted with a phosphorus acid, anhydride, or lower ester. The
epoxide includes an aliphatic epoxide or a styrene oxide. Examples
of useful epoxides include ethylene oxide, propylene oxide, butene
oxide, octene oxide, dodecene oxide, and styrene oxide. In one
embodiment, the epoxide is propylene oxide. The glycols may be
aliphatic glycols having from 1 to 12, or from 2 to 6, or 2 to 3
carbon atoms. The dithiophosphoric acids, glycols, epoxides,
inorganic phosphorus reagents and methods of forming the same are
described in U.S. Pat. Nos. 3,197,405 and 3,544,465. The resulting
acids may then be salted with amines. An example of suitable
dithiophosphoric acid is prepared by adding phosphorus pentoxide
(about 64 grams) at 58.degree. C. over a period of 45 minutes to
514 grams of hydroxypropyl
O,O-di(4-methyl-2-pentyl)phosphorodithioate (prepared by reacting
di(4-methyl-2-pentyl)-phosphorodithioic acid with 1.3 moles of
propylene oxide at 25.degree. C.). The mixture is heated at
75.degree. C. for 2.5 hours, mixed with a diatomaceous earth and
filtered at 70.degree. C. The filtrate contains 11.8% by weight
phosphorus, 15.2% by weight sulfur, and an acid number of 87
(bromophenol blue).
[0186] The dithiocarbamate-containing compounds may be prepared by
reacting a dithiocarbamate acid or salt with an unsaturated
compound. The dithiocarbamate containing compounds may also be
prepared by simultaneously reacting an amine, carbon disulfide and
an unsaturated compound. Generally, the reaction occurs at a
temperature from 25.degree. C. to 125.degree. C.
[0187] Examples of suitable olefins that may be sulfurized to form
the sulfurized olefin include propylene, butylene, isobutylene,
pentene, hexane, heptene, octane, nonene, decene, undecene,
dodecene, undecyl, tridecene, tetradecene, pentadecene, hexadecene,
heptadecene, octadecene, nonodecene, eicosene, and mixtures
thereof. Hexadecene, heptadecene, octadecene, nonodecene, eicosene,
and mixtures thereof, and their dimers, trimers and tetramers are
especially useful olefins. Alternatively, the olefin may be a
Diels-Alder adduct of a diene such as 1,3-butadiene and an
unsaturated ester, such as butyl acrylate.
[0188] Another class of sulfurized olefin includes fatty acids and
their esters. The fatty acids are often obtained from vegetable oil
or animal oil; and typically contain 4 to 22 carbon atoms. Examples
of suitable fatty acids and their esters include triglycerides,
oleic acid, linoleic acid, palmitoleic acid, and mixtures thereof.
The fatty acids may be obtained from lard oil, tail oil, peanut
oil, soybean oil, cottonseed oil, sunflower seed oil, and mixtures
thereof. In one embodiment fatty acids and/or ester are mixed with
olefins.
[0189] In an alternative embodiment, the ashless antiwear agent may
be a monoester of a polyol and an aliphatic carboxylic acid, often
an acid containing 12 to 24 carbon atoms. Often the monoester of a
polyol and an aliphatic carboxylic acid is in the form of a mixture
with a sunflower oil or the like, which may be present in the
friction modifier mixture from 5 to 95, in several embodiments from
10 to 90, or from 20 to 85, or 20 to 80 weight percent of the
mixture. The aliphatic carboxylic acids (especially a
monocarboxylic acid) which form the esters are those acids
typically containing 12 to 24, or from 14 to 20 carbon atoms.
Examples of carboxylic acids include dodecanoic acid, stearic acid,
lauric acid, behenic acid, and oleic acid.
[0190] Polyols include diols, triols, and alcohols with higher
numbers of alcoholic OH groups. Polyhydric alcohols include
ethylene glycols, including di-, tri- and tetraethylene glycols;
propylene glycols, including di-, tri- and tetrapropylene glycols;
glycerol; butane diol; hexane diol; sorbitol; arabitol; mannitol;
sucrose; fructose; glucose; cyclohexane diol; erythritol; and
pentaerythritols, including di- and tripentaerythritol. The polyol
can be diethylene glycol, triethylene glycol, glycerol, sorbitol,
pentaerythritol, dipentaerythritol, or mixtures thereof.
[0191] The commercially available monoester known as "glycerol
monooleate" is believed to include 60.+-.5 percent by weight of
glycerol monooleate, 35.+-.5 percent glycerol dioleate, and less
than 5 percent trioleate and oleic acid. The amounts of the
monoesters, described above, are calculated based on the actual,
corrected, amount of polyol monoester present in any such
mixture.
[0192] The antiwear agent(s) may be present at from 0.0% wt. to 5
wt. %, or 0.5% wt. to 5 wt. %, or 0.5 wt. % to 3 wt. %, or 1 wt. %
to 2 wt. % of the lubricating composition.
[0193] 6. Antiscuffing Agents
[0194] The lubricating composition may also contain an antiscuffing
agent. Antiscuffing agent compounds are believed to decrease
adhesive wear and are often sulfur containing compounds. Typically,
the sulfur containing compounds include sulfurized olefins, organic
sulfides and polysulfides, such as dibenzyldisulfide,
bis-(chlorobenzyl) disulfide, dibutyl tetrasulfide, di-tertiary
butyl polysulfide, sulfurized methyl ester of oleic acid,
sulfurized alkylphenol, sulfurized dipentene, sulfurized terpene,
sulfurized Diels-Alder adducts, alkyl sulphenyl N'N-dialkyl
dithiocarbamates, the reaction product of polyamines with polybasic
acid esters, chlorobutyl esters of 2,3-dibromopropoxyisobutyric
acid, acetoxymethyl esters of dialkyl dithiocarbamic acid and
acyloxyalkyl ethers of xanthogenic acids, and mixtures thereof.
[0195] The antiscuffing agent(s) may be present at from 0% wt. to 6
wt. %, or 1 wt. % to 6 wt. %, or 3 wt. % to 6 wt. % of the
lubricating composition.
[0196] 7. Extreme Pressure Agents
[0197] Extreme Pressure (EP) agents that are soluble in the oil
include sulfur- and chlorosulfur-containing EP agents, chlorinated
hydrocarbon EP agents and phosphorus EP agents. Examples of such EP
agents include chlorinated wax; sulfurized olefins (such as
sulfurized isobutylene), organic sulfides and polysulfides such as
dibenzyldisulfide, bis-(chlorobenzyl) disulfide, dibutyl
tetrasulfide, sulfurized methyl ester of oleic acid, sulfurized
alkylphenol, dimercaptothiadiazoles, sulfurized dipentene,
sulfurized terpene, and sulfurized Diels-Alder adducts;
phosphosulfurized hydrocarbons such as the reaction product of
phosphorus sulfide with turpentine or methyl oleate; phosphorus
esters such as the dihydrocarbon and trihydrocarbon phosphites,
e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexyl
phosphite, pentylphenyl phosphite; dipentylphenyl phosphite,
tridecyl phosphite, distearyl phosphite and polypropylene
substituted phenol phosphite; metal thiocarbamates such as zinc
dioctyldithiocarbamate and barium heptyiphenol diacid; amine salts
of alkyl and dialkylphosphoric acids or derivatives including, for
example, the amine salt of a reaction product of a
dialkyldithiophosphoric acid with propylene oxide and subsequently
followed by a further reaction with P.sub.2O.sub.5; and mixtures
thereof (as described, for example, in U.S. Pat. No.
3,197,405).
[0198] Suitable dimercaptothiadiazoles include
hydrocarbyl-substituted 2,5-dimercapto-1,3,4-thiadiazole and
unsubstituted equivalents thereof that are substantially soluble at
25.degree. C. in non-polar media such as an oil of lubricating
viscosity. The total number of carbon atoms in the
hydrocarbyl-substituents, which tend to promote solubility, will
generally be 8 or more, or 10 or more, or at least 12. If the
thiadiazole has two or more hydrocarbyl groups, the number of
carbon atoms per group may be below 8 provided the total number of
carbons is 8 or more.
[0199] Examples of dimercaptothiadiazoles include
2,5-(tert-octyldithio)-1,3,4-thiadiazole
2,5-(tert-nonyldithio)-1,3,4-thiadiazole,
2,5-(tert-decyldithio)-1,3,4-thiadiazole,
2,5-(tert-undecyldithio)-1,3,4-thiadiazole,
2,5-(tert-dodecyldithio)-1,3,4-thiadiazole,
2,5-(tert-tridecyldithio)-1,3,4-thiadiazole,
2,5-(tert-tetradecyldithio)-1,3,4-thiadiazole,
2,5-(tert-pentadecyldithio)-1,3,4-thiadiazole,
2,5-(tert-hexadecyldithio)-1,3,4-thiadiazole,
2,5-(tert-heptadecyldithio)-1,3,4-thiadiazole,
2,5-(tert-octadecyldithio)-1,3,4-thiadiazole,
2,5-(tert-nonadecyldithio)-1,3,4-thiadiazole or
2,5-(tert-eicosyldithio)-1,3,4-thiadiazole, and oligomers and
mixtures thereof. In one embodiment, the dimercaptothiadiazole
includes 2,5-dimercapto-1,3,4-thiadiazole.
[0200] Dimercaptothiadiazoles may be derived from
2,5-dimercapto-1,3,4-thiadiazole, or a hydrocarbyl-substituted
2,5-dimercapto-1,3,4-thiadiazole, or an oligomer thereof. The
oligomers of hydrocarbyl-substituted
2,5-dimercapto-1,3,4-thiadiazole typically form by forming a
sulfur-sulfur bond between 2,5-dimercapto-1,3,4-thiadiazole units
to form oligomers of two or more of the thiadiazole units. In one
embodiment the dimercaptothiadiazole (typically a
2,5-dimercapto-1,3,4-thiadiazole) may be formed by reacting a
dimercaptothiadiazole with an ethylenically unsaturated amide or
ester. The amide or ester may include hydrocarbyl-(meth)acrylate or
hydrocarbyl-(meth)acrylamide, a hydrocarbyl-substituted maleate, a
hydrocarbyl-substituted crotonate, a hydrocarbyl-substituted
cinnamate, or mixtures thereof.
[0201] In one embodiment, the dimercaptothiadiazole (typically a
2,5-dimercapto-1,3,4-thiadiazole) may be a compound represented by
the formula:
##STR00011##
[0202] where:
[0203] R.sub.1 may be an alkylene group containing 1 to 5, or 1 to
3, or 2 carbon atoms;
[0204] R.sub.2 may be a hydrocarbyl group containing 1 to 16, or 2
to 8, or 4 carbon atoms;
[0205] Y may be --O-- or >NR.sub.3 (typically Y may be --O--);
and
[0206] R.sub.3 may be hydrogen or R.sub.2.
[0207] The dimercaptothiadiazole of the formula above may be
prepared by reacting the appropriate hydrocarbyl-(meth)acrylate or
hydrocarbyl-(meth)acrylamide with 2,5-dimercapto-1,3,4-thiadiazole.
The reaction of hydrocarbyl-(meth)acrylate or
hydrocarbyl-(meth)acrylamide with 2,5-dimercapto-1,3,4-thiadiazole
may be carried out at a temperature in the range of 50.degree. C.
to 150.degree. C., or 70.degree. C. to 120.degree. C., or
80.degree. C. to 100.degree. C.
[0208] In one embodiment, the dimercaptothiadiazole salt (typically
a 2,5-dimercapto-1,3,4-thiadiazole salt) may be prepared by
reacting a dimercaptothiadiazole with an epoxide.
[0209] The EP agents may be present at from 0% wt. to 6 wt. %, or
1% wt. to 6 wt. %, or 2 wt. % to 6 wt. %, or 3 wt. % to 6 wt. % of
the lubricating composition.
[0210] 8. Corrosion Inhibitors, Foam Inhibitors, Pour Point
Depressants, Friction Modifiers
[0211] Corrosion inhibitors that may be useful include fatty
amines, octylamine octanoate, and condensation products of
dodecenyl succinic acid or anhydride and a fatty acid such as oleic
acid with a polyamine.
[0212] The corrosion inhibitor(s) may be present at 0 wt. % to 3
wt. %, or 0.01% wt. to 3 wt. %, or 0.01 to 1 wt. %, or 0.05 to 0.5
wt. % of the lubricating composition.
[0213] Foam inhibitors that may be useful in the exemplary
compositions include silicones; copolymers of ethyl acrylate and
2-ethylhexylacrylate, which can optionally further include vinyl
acetate; and demulsifiers including trialkyl phosphates,
polyethylene glycols, polyethylene oxides, polypropylene oxides and
(ethylene oxide-propylene oxide) polymers.
[0214] Pour point depressants that may be useful in the exemplary
compositions include polyalphaolefins, esters of maleic
anhydride-styrene copolymers, and poly(meth)acrylates,
polyacrylates, and polyacrylamides, such as
polyalkylmethacrylates.
[0215] Friction modifiers that may be useful in the exemplary
compositions include fatty acid derivatives such as amines, esters,
epoxides, fatty imidazolines, condensation products of carboxylic
acids and polyalkylene-polyamines and amine salts of
alkylphosphoric acids.
[0216] Examples of suitable friction modifiers include long chain
fatty acid derivatives of amines, long chain fatty esters, or
derivatives of long chain fatty epoxides; fatty imidazolines such
as condensation products of carboxylic acids and
polyalkylene-polyamines; amine salts of alkylphosphoric acids;
fatty alkyl tartrates; fatty alkyl tartrimides; fatty alkyl
tartramides; fatty glycolates; fatty glycolamides fatty
phosphonates; fatty phosphites; borated phospholipids, borated
fatty epoxides; glycerol esters; borated glycerol esters; fatty
amines; alkoxylated fatty amines; borated alkoxylated fatty amines;
hydroxyl and polyhydroxy fatty amines including tertiary hydroxy
fatty amines; hydroxy alkyl amides; metal salts of fatty acids;
metal salts of alkyl salicylates; fatty oxazolines; fatty
ethoxylated alcohols; condensation products of carboxylic acids and
polyalkylene polyamines; or reaction products from fatty carboxylic
acids with guanidine, aminoguanidine, urea, or thiourea and salts
thereof. As used herein the term "fatty alkyl or fatty" in relation
to friction modifiers means a carbon chain having 10 to 22 carbon
atoms, typically a straight carbon chain. Friction modifiers may
also encompass materials such as sulfurized fatty compounds and
olefins, molybdenum dialkyldithiophosphates, molybdenum
dithiocarbamates, and monoesters of a polyol and an aliphatic
carboxylic acid derived or derivable from sunflower oil or soybean
oil.
[0217] In one embodiment, the friction modifier may be a long chain
fatty acid ester. In another embodiment, the long chain fatty acid
ester may be a monoester and in another embodiment the long chain
fatty acid ester may be a (tri)glyceride.
[0218] The friction modifier may be present at 0 wt. % to 7 wt. %,
or 0.1 wt. % to 6 wt. %, or 0.25 wt. % to 3.5 wt. %, or 0.5 wt. %
to 2.5 wt. %, or 1 wt. % to 2.5 wt. %, or 0.05 wt. % to 0.5 wt. %,
or 5 to 7 wt. % of the lubricating composition.
[0219] To the extent that any of the performance additives, other
than dispersants, employed in the lubricating composition also act
as dispersants of the products of oxidation, they may be avoided or
minimized, as discussed for the dispersants above, such that the
total of all dispersants is no more than 2 wt. %, or no more than
1.5 wt. %, or no more than 1 wt. %, or no more than 0.5 wt. %, or
no more than 0.2 wt. %.
[0220] III. Industrial Application
[0221] The method and exemplary lubricating composition may be
suitable for refrigeration lubricants, greases, gear oils, axle
oils, drive shaft oils, traction oils, manual transmission oils,
automatic transmission oils, metal working fluids, hydraulic oils,
or internal combustion engine oils. The exemplary lubricating
composition may be supplied to a mechanical device, such as a gear
or transmission system, without addition of any further
dispersants, and used for lubrication during normal operation of
the mechanical device.
[0222] In one embodiment, the method and exemplary lubricating
composition may be suitable for at least one of gear oils, axle
oils, drive shaft oils, traction oils, manual transmission oils and
automatic transmission oils.
[0223] As an example, the exemplary lubricating composition finds
application as a gear oil.
[0224] The exemplary copolymer may also find application in
automatic transmission systems, such as continuously variable
transmissions (CVT), infinitely variable transmissions (IVT),
toroidal transmissions, continuously slipping torque converter
clutches (CSTCC), stepped automatic transmissions or dual clutch
transmissions (DCT).
[0225] The use (may also be referred to as a method) and
lubricating composition described herein are capable of providing a
lubricant with acceptable/improved dispersancy properties
(cleanliness) and oxidation control, and may also provide one (or
at least two, or all) of acceptable or improved shear stability,
acceptable or improved viscosity index control, and acceptable or
improved low temperature viscosity.
[0226] In several embodiments, a suitable lubricating composition
includes the copolymer present (on an actives basis) in ranges as
shown Table I.
TABLE-US-00001 TABLE 1 Embodiments (wt. % of lubricating
composition) A B C Exemplary copolymer 5-95 30-60 40-50 Other
Performance Additives 0-20 0.5-20 0.5-15 Oil of Lubricating
Viscosity 0.01-95 .sup. 20-69.5 .sup. 35-59.5 Total of three
components 100 100 100
[0227] Unexpectedly, the exemplary copolymer-containing fluids were
found to disperse the byproducts of oxidation without the use of
additional dispersant. The lubricating composition was shown to
improve in this respect as dispersant is reduced or removed.
[0228] The following examples provide an illustration of the
invention. These examples are non-exhaustive and are not intended
to limit the scope of the invention.
EXAMPLES
Example 1
Preparation of an Amine-Capped Esterified Copolymer (Copolymer
1)
[0229] A 5 L reaction flask was charged with 407.8 g of maleic
anhydride (MAA), 700 g of 1-dodecene and 1108 g of toluene. A molar
ratio of the 1-dodecene:maleic anhydride was 1:1. The flask was
fitted with a PTFE gasket and a 5-port flange lid equipped with an
overhead stirrer, stirrer guide, thermocouple, nitrogen inlet (250
cm.sup.3/min nitrogen), silicon septa with peristaltic pump
attached via cannula and a water condenser. The reaction flask and
its contents were heated to 108.degree. C.
[0230] A mixture of 35.98 grams of Trigonox.RTM.21S (a commercially
available tert-butyl peroxy-2-ethylhexanoate initiator from Akzo
Nobel), 26.94 g of n-dodecylmercaptan, and 485 g of toluene were
mixed together and added to the reaction flask over 240 min. via
the peristaltic pump. The reaction mixture was stirred at
108.degree. C. for several hours. The reaction flask was fitted
with a Dean-Stark trap and the reaction mixture heated to
120.degree. C. with stirring. Using the peristaltic pump, 618.1 g
of Alfol 810.TM. was added over 45 min. and the resulting reaction
mixture stirred for 1 hr. An additional 618 g of Alfol 810.TM. and
28.55 g of a 70% aqueous solution of methane sulfonic acid were
added to the reaction flask over 3 to 4 hrs while gradually
increasing the reaction temperature to 135.degree. C. The reaction
mixture was then heated to 145.degree. C. and 70 g of n-butanol and
14.27 g of 70% aqueous solution of methane sulfonic acid were added
and stirred for 1 hour. An additional 70 g of n-butanol was added
and the reaction stirred for 2 hours. The addition of n-butanol was
continued until the 1-dodecene:maleic anhydride copolymer was
esterified to at least 97%. Sufficient sodium hydroxide (50%
aqueous sodium hydroxide solution) was added to quench the methane
sulfonic acid and the mixture was stirred for 1 hour followed by
the addition of 47.98 g of 4-(3-aminopropyl)morpholine and stirred
for an additional 2 hours. The reaction flask was fitted for vacuum
stripping and the resultant product vacuum-stripped (-28 in Hg) at
150.degree. C. and held for 2.5 hours. The vacuum was removed and
the flask was cooled to 120.degree. C. The resulting reaction
mixture was filtered using fax-5 and filter cloth.
[0231] Product analysis showed a 0.103 wt. % nitrogen content, a
kinematic viscosity at 100.degree. C. (KV100), determined employing
ASTM method D445, was 288 cSt., and TAN was 4.5 mg KOH/g. TAN is
the total acid number, determined by 0.1M KOH titration with
phenolphthalein indicator in toluene/isopropanol/water (500:495:5
parts), measured in mg KOH/g.
[0232] GPC run in tetrahydrofuran against polystyrene standards
showed a M.sub.w of 16,400, M.sub.n of 7900, and a PDI (Mw/Mn) of
2.06 for the esterified, amine-capped copolymer.
Example 2
Preparation of an Amine-Capped Esterified Copolymer (Copolymer
2)
[0233] The same procedure used in Example 1 was followed except
that the copolymer of 1-dodecene:maleic anhydride made in Example 1
was esterified with a mixture of 84.4 weight % Alfol 810.TM. and
15.6 weight % Isofol 16.TM. and amine end capping of the esterified
copolymer was performed with n-butylamine.
[0234] Product analysis showed a 0.23 wt. % nitrogen content, a
kinematic viscosity at 100.degree. C. (KV100), determined employing
ASTM method D445, of 390 cSt., and TAN was 3.3 mg KOH/g.
[0235] GPC run in tetrahydrofuran against polystyrene standards
showed a M.sub.w of 16,448, M.sub.n of 7,300, and a PDI of 2.25 for
the esterified, amine-capped copolymer.
Example 3
Preparation of an Esterified Copolymer without Amine Cap (Copolymer
3)
[0236] A similar procedure to that used in Example 1 was followed
except that the copolymer of 1-dodecene:maleic anhydride made in
Example 1 was esterified with a mixture of Alfol 810.TM. and Isofol
16.TM. in a 9:1 weight % ratio. Following the esterification with
Alfol 810.TM. and Isofol 16.TM., the esterification of the
copolymer was finished with n-butanol, as described in Example 1.
No amine end capping of the esterified copolymer was performed.
[0237] Product analysis showed a 100.degree. C. (KV100), determined
with ASTM method D445, was 248 cSt. and TAN was 6.3 mg KOH/g.
[0238] GPC run in tetrahydrofuran against polystyrene standards
showed a M.sub.w of 13,177, M.sub.n of 6549, and a PDI of 2.01 for
the esterified copolymer.
Example 4
Preparation of an Amine-Capped Esterified Copolymer (Copolymer
4)
[0239] A similar procedure to that used in Example 1 was followed
except that the copolymer of 1-dodecene:maleic anhydride made in
Example 1 was esterified with a mixture of Alfol 810.TM. and Isofol
16.TM. in a 9:1 weight % ratio. Following the esterification with
Alfol 810.TM. and Isofol 16.TM., the esterification of the
copolymer was finished with n-butanol as described in Example 1,
and amine end capping of the esterified copolymer was performed
with aminoethylethyleneurea.
[0240] Product analysis showed a 0.14 wt. % nitrogen content, a
kinematic viscosity at 100.degree. C. (KV100), determined with ASTM
method D445, of 211.3 cSt., and TAN was 3.3 mg KOH/g.
Example 5
Preparation of Lubricating Compositions
[0241] The amine-capped esterified copolymer (Copolymer 2) prepared
according to Example 2 was used to prepare lubricating compositions
A, B, and C (COMP. A, COMP. B, and COMP. C) as shown in TABLE 2.
All amounts are in wt. %. The components of the performance package
(dispersant-free) are given in TABLE 3 and are expressed on an oil
free basis. Compositions D, E, and F (COMP. D, COMP. E and COMP. F
respectively) were prepared with esterified only copolymer
(Copolymer 3) prepared according to Example 3. All amounts are in
wt. %.
[0242] It is to be noted that the actual amounts of dispersant in
the composition are only 67% of those shown in TABLE 2 since the
dispersant is diluted with 33 wt. % mineral oil. Thus, the maximum
amount of dispersant used in these experiments was approximately
1.5 wt. %
TABLE-US-00002 TABLE 2 COMP D COMP A COMP B COMP C Run 1 Run 2 COMP
E COMP F Example 2 copolymer 40.48 41.43 41.43 Example 3 copolymer
45.0 46.5 46.5 46.5 Dispersant (borated 2.25 1.125 0.225 2.25 2.25
1.125 0 polyisobutylene succinimide) 33% mineral oil Base Oil
1-Group III 36.99 37.121 37.796 38.17 32.47 33.32 34.16 Base oil,
Visc. @100.degree. C. ~4 cSt) Synthetic aliphatic 12.33 12.374
12.599 11.2 10.825 11.106 11.387 hydrocarbon Pour point depressant
0.2 0.2 0.2 0.2 0.2 0.2 0.2 (polyalkylmethacrylate) 50% mineral oil
Performance Package 7.75 7.75 7.75 7.75 7.75 7.75 7.75
TABLE-US-00003 TABLE 3 wt. % present Description Function 22.7
Phosphoric acid esters/amine Antiwear salt 41.0 Olefin sulfide
Extreme pressure agent 19.6 Sulfurized isobutylene Extreme pressure
agent 0.12 Alkenyl amide Friction modifier 5.07 Antifoam agents and
Antifoam agents and Corrosion inhibitors Corrosion inhibitors
Balance Diluent Oil (Group III, 4 cSt)
Oxidative Stability Testing
[0243] Compositions A, B, C, and D were oxidized using the CEC
L-48-00 procedure B (whereby air is passed through 100 ml of oil at
a rate of 5 liters/hour for 192 hours at 160.degree. C.). The
results are shown in TABLE 4, expressed as the percentage increase
in kinematic viscosity at 40.degree. C. (% KV40), and at
100.degree. C. (% KV100). The test procedure also measures a tube
rating, and the dispersancy rating was calculated (as described
above). For the spot rating, higher values indicate better
results.
[0244] The kinematic viscosity is determined according to ASTM
method D445 at 100.degree. C. (KV100) and at 40.degree. C.
(KV40).
[0245] The viscosity index (VI) is determined according to ASTM
method D2270.
TABLE-US-00004 TABLE 4 COMP. D COMP. A COMP. B COMP. C Run 1 Run 2
COMP. E COMP. F CEC_TUBE 3 3 3 2 2 3 3 RATING SPOT RATING 30 46 79
66 74 25 38 % KV40 % 109.7 115.6 105 212.5 173 77 54 % KV100 % 91
95.2 85 181.3 149 64 43.8 TAN_CHANGE 2.4 3.1 2.4 7.7 mg KOH/g
.sup.1KV40, cSt 103.28 101.79 97.52 114.8 125.4 118.2 111.3
.sup.1KV100, cSt 18.14 18.02 17.53 18.75 20.39 19.51 18.69 .sup.1VI
195 196 198 184 187 188 188 .sup.1Viscosity at start of test.
[0246] The DKA results of COMP. A, COMP. B and COMP. C show that as
the dispersant concentration is decreased, a higher dispersant spot
rating at equal tube rating at approximately equal viscosity
increase is achieved. While the DKA results of COMP. D indicate
higher oxidation of the oil (i.e., higher TAN change and higher
KV100), the spot rating indicates that the oxidation products are
still dispersed by the exemplary copolymer, Copolymer 3 (Example 3)
despite the copolymer not having been amine capped.
Example 6
Comparison with Lubricating Compositions Containing Other Viscosity
Index Improvers
[0247] Lubricating compositions containing other viscosity index
improvers were investigated to determine whether they would also
show this unexpected result. The compositions tested are shown in
TABLE 5. The Exemplary copolymers, Copolymer 1 (Example 1) and
Copolymer 4 (Example 4), were used to form Compositions G, H, and J
(Example 1) and Compositions K, L and M (Example 4).
Polyalphaolefin (PAO 100), a Group IV base oil, was used to form
Comparative Compositions N, O, and P, and poly(alkyl methacrylate)
(PMA) was used in the preparation of Comparative Compositions Q,
and R. The dispersant, where used, was a borated polyisobutylene
succinimide dispersant. The same performance package disclosed in
TABLE 3 was used. The results are shown in TABLE 6.
TABLE-US-00005 TABLE 5 Lubricating Compositions Lubricating
Composition G H J K L M Dispersant (33% mineral 2.25 1.125 0 2.25
1.125 0 oil) Base Oil 3-Group III 33.3 33.17 32.97 32.47 33.32
34.16 Base oil, Visc. @100.degree. C.~4 cSt Synthetic aliphatic
11.1 11.05 10.98 10.82 11.11 11.39 hydrocarbon PMA 22% mineral oil
PAO 100 Copolymer 1 45.4 46.7 48.1 Copolymer 4 45.6 45.6 45.6 Pour
point depressant 0.2 0.2 0.2 0.2 0.2 0.2 (polyalkylmethacrylate)
50% mineral oil Performance package 7.75 7.75 7.75 7.75 7.75 7.75
Lubricating Composition N O P Q R N Dispersant (33% mineral 2.25
1.125 0 2.25 0 2.25 oil) Base Oil 3-Group III 35.7 35.57 35.44
36.98 36.87 35.7 Base oil, Visc. @100.degree. C.~4 cSt Synthetic
aliphatic 11.9 11.85 11.81 12.32 12.28 11.9 hydrocarbon PMA 22%
mineral oil 40.5 42.9 PAO 100 42.2 43.5 44.8 42.2 Copolymer 1
Copolymer 4 Pour point depressant 0.2 0.2 0.2 0.2 0.2 0.2
(polyalkylmethacrylate) 50% mineral oil Performance package 7.75
7.75 7.75 7.75 7.75 7.75
TABLE-US-00006 TABLE 6 DKA Performance of Lubricating Compositions
Lubricating Composition G H J K L M OXIDATION, DKA CEC_TUBE 3 3 3 2
2 3 RATING SPOT 91 93 100 100 100 41 RATING % KV40 176.3 108.3
109.4 206 118.4 109.1 % KV100 142.4 87.4 87.3 163.4 97.5 87.5 TAN
12 3.7 5.1 CHANGE mg KOH/g KV40, cSt 109.2 106.4 106.9 122.3 115.9
108.9 KV100, cSt 18.19 17.96 18.12 19.68 18.95 18.05 VI 186 187 189
184 184 184 Lubricating Composition N O P Q R OXIDATION, DKA
CEC_TUBE RATING 3 3 3 3 3 SPOT RATING 23 35 49 91 92 % KV40 166.1
28.7 29.1 214.9 198.3 % KV100 128.2 24 23.9 145.4 145.3 TAN CHANGE
mg 7 0 -0.1 9.2 6.1 KOH/g KV40, cSt 129.9 131 132.6 121.8 123.9
KV100, cSt 18.78 18.91 19.14 18.72 19.02 VI 163 163 164 173 174
[0248] The results show that a change in dispersant level provides
no change in dispersancy for the PMA bulk fluid, as demonstrated by
the spot rating. PAO100 shows a modest improvement in spot rating
but the results are still significantly lower (i.e., not acceptable
for some applications) than spot ratings achieved using the
exemplary copolymers. The exemplary Copolymer 1 shows an
improvement in spot rating and viscosity increase at equivalent CEC
tube rating (3). The results suggest that the exemplary copolymer
is capable of fully dispersing the products of oxidation without
the addition of further dispersants. The results also indicate that
PAO100 cannot achieve this, with or without dispersant, and that
PMA has a more substantial viscosity increase, tube rating and
incomplete dispersancy under the same conditions.
[0249] Each of the documents referred to above is incorporated
herein by reference. Except in the Examples, or where otherwise
explicitly indicated, all numerical quantities in this description
specifying amounts of materials, reaction conditions, molecular
weights, number of carbon atoms, and the like, are to be understood
as modified by the word "about." Unless otherwise indicated, each
chemical or composition referred to herein should be interpreted as
being a commercial grade material which may contain the isomers,
by-products, derivatives, and other such materials which are
normally understood to be present in the commercial grade. However,
the amount of each chemical component is presented exclusive of any
solvent or diluent oil, which may be customarily present in the
commercial material, unless otherwise indicated. It is to be
understood that the upper and lower amount, range, and ratio limits
set forth herein may be independently combined. Similarly, the
ranges and amounts for each element of the invention may be used
together with ranges or amounts for any of the other elements.
[0250] As used herein, the expression "consisting essentially of"
permits the inclusion of substances that do not materially affect
the basic and novel characteristics of the composition under
consideration. As used herein any member of a genus (or list) may
be excluded from the claims.
[0251] As used herein, the term "(meth) acrylic" and related terms
includes both acrylic and methacrylic groups.
[0252] As used herein, the term "a primary alcohol branched at the
.beta.- or higher position" relates to an alcohol with branching at
the 2-position or a higher position (e.g., 3-, or 4-, or 5-, or 6-,
or 7-position, etc.).
[0253] As used herein, the term "hydrocarbyl substituent" or
"hydrocarbyl group" is used in its ordinary sense, which is
well-known to those skilled in the art. Specifically, it refers to
a group having a carbon atom directly attached to the remainder of
the molecule and having predominantly hydrocarbon character.
Examples of hydrocarbyl groups include:
[0254] a. hydrocarbon substituents, that is, aliphatic (e.g., alkyl
or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl)
substituents, and aromatic-, aliphatic-, and alicyclic-substituted
aromatic substituents, as well as cyclic substituents wherein the
ring is completed through another portion of the molecule (e.g.,
two substituents together form a ring);
[0255] b. substituted hydrocarbon substituents, that is,
substituents containing non-hydrocarbon groups which, in the
context of this invention, do not alter the predominantly
hydrocarbon nature of the substituent (e.g., halo (especially
chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto,
nitro, nitroso, and sulfoxy);
[0256] c. hetero substituents, that is, substituents which, while
having a predominantly hydrocarbon character, in the context of
this invention, contain other than carbon in a ring or chain
otherwise composed of carbon atoms; and
[0257] d. heteroatoms include sulfur, oxygen, nitrogen, and
encompass substituents as pyridyl, furyl, thienyl and imidazolyl.
In general, no more than two, in one aspect 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.
[0258] While the invention has been explained in relation to its
preferred embodiments, it is to be understood that various
modifications thereof will become apparent to those skilled in the
art upon reading the specification. Therefore, it is to be
understood that the invention disclosed herein is intended to cover
such modifications as fall within the scope of the appended
claims.
[0259] It will be appreciated that variants of the above-disclosed
and other features and functions, or alternatives thereof, may be
combined into many other different systems or applications. Various
presently unforeseen or unanticipated alternatives, modifications,
variations or improvements therein may be subsequently made by
those skilled in the art which are also intended to be encompassed
by the following claims.
* * * * *