U.S. patent application number 14/034864 was filed with the patent office on 2014-04-24 for high viscosity index lubricating oil base stock and viscosity modifier combinations, and lubricating oils derived therefrom.
This patent application is currently assigned to ExxonMobil Research and Engineering Company. The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Willie Allan Givens, Percy Rohinton Kanga, Jared Michael Robillard.
Application Number | 20140113847 14/034864 |
Document ID | / |
Family ID | 49304430 |
Filed Date | 2014-04-24 |
United States Patent
Application |
20140113847 |
Kind Code |
A1 |
Givens; Willie Allan ; et
al. |
April 24, 2014 |
HIGH VISCOSITY INDEX LUBRICATING OIL BASE STOCK AND VISCOSITY
MODIFIER COMBINATIONS, AND LUBRICATING OILS DERIVED THEREFROM
Abstract
A lubricating composition including a first base stock component
including: one or more metallocene catalyzed polyalphaolefins
(mPAOs), each mPAO having a kinematic viscosity (Kv.sub.100) from
40 cSt to 155 cSt and a viscosity index (VI) from 150 to 207; a
second base stock including one or more polyalphaolefins (PAOs),
each PAO having a kinematic viscosity (Kv.sub.100) less than 10 cSt
and a VI from 130 to 145; and a viscosity modifier including a
copolymer having units derived from monomers of (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with an alcohol. A lubricant
including the above lubricating composition. A method for improving
fuel efficiency, while maintaining or improving wear control, load
carrying capacity and/or traction reduction in a driveline device,
e.g., gears and transmissions, lubricated with a lubricating oil,
by using as the lubricating oil the above lubricant.
Inventors: |
Givens; Willie Allan;
(Williamstown, NJ) ; Kanga; Percy Rohinton;
(Cherry Hill, NJ) ; Robillard; Jared Michael;
(Collingswood, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Assignee: |
ExxonMobil Research and Engineering
Company
Annandale
NJ
|
Family ID: |
49304430 |
Appl. No.: |
14/034864 |
Filed: |
September 24, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61717947 |
Oct 24, 2012 |
|
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|
Current U.S.
Class: |
508/468 ;
508/470; 508/471; 508/472 |
Current CPC
Class: |
C10M 2209/084 20130101;
C10M 169/041 20130101; C10M 145/16 20130101; C10N 2030/68 20200501;
C10N 2030/06 20130101; C10N 2030/04 20130101; C10N 2020/019
20200501; C10N 2030/10 20130101; C10N 2040/044 20200501; C10N
2030/08 20130101; C10N 2040/04 20130101; C10M 149/06 20130101; C10M
2217/06 20130101; C10M 149/04 20130101; C10M 2205/0285 20130101;
C10N 2030/02 20130101; C10M 145/12 20130101; C10M 2205/0285
20130101; C10N 2020/02 20130101; C10M 2209/084 20130101; C10N
2060/09 20200501; C10M 2205/0285 20130101; C10N 2020/02 20130101;
C10M 2209/084 20130101; C10N 2060/09 20200501 |
Class at
Publication: |
508/468 ;
508/472; 508/470; 508/471 |
International
Class: |
C10M 149/06 20060101
C10M149/06; C10M 149/04 20060101 C10M149/04; C10M 145/16 20060101
C10M145/16; C10M 145/12 20060101 C10M145/12 |
Claims
1. A lubricating composition comprising: a first base stock
component comprising one or more metallocene catalyzed
polyalphaolefins (mPAOs), each mPAO having a kinematic viscosity
(Kv.sub.100) from 40 cSt to 155 cSt and a viscosity index (VI) from
150 to 207; a second base stock comprising one or more
polyalphaolefins (PAOs), each PAO having a kinematic viscosity
(Kv.sub.100) less than 10 cSt and a VI from 130 to 145; and a
viscosity modifier comprising a copolymer having units derived from
monomers of (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof esterified with
an alcohol; wherein at least one of wear control (as determined by
ASTM D4172), load carrying capacity (as determined by ASTM D2783)
and traction reduction (as determined by Mini-Traction Machine
(MTM) Ball-on-Disc apparatus) is improved in a driveline device
lubricated with said lubricating composition as compared to at
least one of wear control, load carrying capacity and traction
reduction achieved with a lubricating composition containing a
viscosity modifier other than said viscosity modifier copolymer, at
an equal or lower kinematic viscosity (Kv@100.degree. C.).
2. The lubricating composition of claim 1 wherein the lubricating
oil base stock comprises a Group I, II, III, IV, V or VI base oil
stock, or mixtures thereof.
3. The lubricating composition of claim 1 wherein the lubricating
oil base stock comprises a synthetic polyalphaolefin (PAO) fluid,
said PAO comprising a polymer of one or more C.sub.8 to C.sub.12
alphaolefin monomers.
4. The lubricating composition of claim 1 wherein the lubricating
oil base stock has a kinematic viscosity (Kv.sub.100) from 4 to 65
cSt at 100.degree. C., and a VI from 140 to 200.
5. The lubricating composition of claim 1 wherein the viscosity
modifier is represented by the formula: ##STR00006## wherein
Formula (I) comprises a copolymer backbone (BB), and one or more
pendant groups, wherein BB is derived from a copolymer of (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof; 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, connecting the
copolymer backbone and a branched hydrocarbyl group contained
within ( ).sub.y; w is the number of pendant groups attached to the
copolymer backbone, which is in the range of 2 to 2000; y is 0, 1,
2 or 3, provided that in at least 1 mol % of the pendant 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 or ammonium cation, and mixtures thereof; p may be an
integer in the range of 1 to 15; and R' and R'' are independently
linear or branched hydrocarbyl groups, and the combined total
number of carbon atoms present in R' and R'' is at least 12.
6. The lubricating composition of claim 1 wherein the alphaolefin
is selected from the group consisting of 1-decene, 1-undecene,
1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-hepta-decene 1-octadecene, and mixtures
thereof.
7. The lubricating composition of claim 1 wherein the ethylenically
unsaturated carboxylic acid or derivative thereof is selected from
the group consisting of acrylic acid, methyl acrylate, methacrylic
acid, maleic acid or anhydride, fumaric acid, itaconic acid or
anhydride or mixtures thereof, and substituted equivalents
thereof.
8. The lubricating composition of claim 1 wherein the alcohol is
selected from the group consisting of 2-ethylhexanol,
2-butyloctanol, 2-hexyldecanol, 2-octyldodecanol,
2-decyltetradecanol, butanol, pentanol, hexanol, heptanol, octanol,
nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol,
pentadecanol, hexadecanol, heptadecanol, octadecanol, eicosanol,
and mixtures thereof.
9. The lubricating composition of claim 1 wherein the viscosity
modifier is a copolymer derived from monomers of (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof, wherein 0.1 to 99.89 percent of the
carboxylic acid units are esterified with a primary alcohol
branched at the .beta.- or higher position, wherein 0.1 to 99.89
percent of the carboxylic acid units are esterified with a linear
alcohol or an alpha-branched alcohol, and wherein 0.01 to 10
percent of the carboxylic acid units has at least one of an amino-,
amido- and/or imido-group.
10. The lubricating composition of claim 1 wherein the viscosity
modifier copolymer has a weight average molecular weight of 45,000
or less.
11. The lubricating composition of claim 1 wherein the first base
stock component is present in the amount from 10 weight percent to
60 weight percent, the second base stock component is present in an
amount from 30 weight percent to 60 weight percent, and the
viscosity modifier is present in an amount from 2 weight percent to
46 weight percent, based on the total weight of the lubricating
composition.
12. A process for producing the lubricating composition of claim 1,
said process comprising: providing a first base stock component
comprising one or more metallocene catalyzed polyalphaolefins
(mPAOs), each mPAO having a kinematic viscosity (Kv.sub.100) from
40 cSt to 155 cSt and a viscosity index (VI) from 150 to 207;
providing a second base stock comprising one or more
polyalphaolefins (PAOs), each PAO having a kinematic viscosity
(Kv.sub.100) less than 10 cSt and a VI from 130 to 145; providing a
viscosity modifier comprising a copolymer having units derived from
monomers of (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof esterified with
an alcohol; and blending the first base stock component, second
base stock component and viscosity modifier in amounts sufficient
to produce the lubricating composition.
13. A lubricant comprising the lubricating composition of claim
1.
14. The lubricant of claim 13 further comprising one or more of an
antioxidant, detergent, dispersant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, anti-foam agent, inhibitor, antiwear, extreme pressure
agent, friction modifier, and antirust additive.
15. A method of lubricating a mechanical device comprising
supplying to the device a lubricating composition of claim 1,
wherein the mechanical device comprises a driveline device.
16. The method of claim 15 wherein the driveline device comprises
gears or transmissions.
17. The lubricant of claim 13 which comprises an axle fluid or
manual transmission fluid (MTF).
18. A method for improving fuel efficiency or shear stability,
while maintaining or improving wear control, load carrying capacity
and/or traction reduction in a driveline device lubricated with a
lubricating oil, by using as the lubricating oil a lubricant of
claim 13.
19. The method of claim 18 wherein the driveline device comprises
gears or transmissions.
20. The method of claim 18 wherein the lubricant comprises an axle
fluid or manual transmission fluid (MTF).
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 61/717,947 filed Oct. 24, 2012, herein
incorporated by reference in its entirety.
FIELD
[0002] This disclosure relates to high viscosity index lubricating
oil base stock (e.g., metallocene catalyzed polyalphaolefin and
polyalphaolefin fluid) and viscosity modifier (e.g.,
ester-containing copolymer) combinations, lubricating oils derived
therefrom, processes for preparing same, and methods of use
thereof. This disclosure relates to lubricating driveline devices,
e.g., gears and transmissions, using the lubricating oils to
improve fuel efficiency without sacrificing driveline device
durability.
BACKGROUND
[0003] Environmental regulations are driving vehicle fuel economy
standards and there is increased emphasis on and market demand for
higher efficiency driveline fluids, particularly axle oils that can
deliver fuel economy and maintain hardware protection capability. A
proven approach to enhancing lubricant derived fuel efficiency is
lower fluid viscosity. Since equipment durability cannot be
compromised, equal or lower viscosity lubricants must deliver
improved efficiency while retaining the same level of protection
against various types of hardware damage (e.g., wear, micropitting,
scuffing, scoring, and the like). Improved durability and reduced
component wear increases equipment operating life and reduces
maintenance costs and downtime. Improved shear stability is
likewise desirable to provide enduring performance (i.e., oil film
stability) throughout the useful life of the lubricant.
Additionally, different transmission applications have specific
friction requirements, some of which benefit from higher
friction.
[0004] Lubricants in commercial use today are prepared from a
variety of natural and synthetic base stocks admixed with various
additive packages and solvents depending upon their intended
application. The base stocks typically include mineral oils,
polyalphaolefins (PAO), gas-to-liquid base oils (GTL), silicone
oils, phosphate esters, diesters, polyol esters, and the like.
[0005] Viscosity index improvers are known to be added to
lubricating oil compositions to reduce the change in viscosity of
the lubricant as a function of temperature. The most conventional
types of viscosity index improvers used in axle and transmission
oil applications include polyisobutylene and polymers of
methacrylates. More recent viscosity index improver technologies
consist of olefins (such as copolymers of alpha-olefins and maleic
anhydride and esterified derivatives thereof). These viscosity
index improvers tend to incorporate ester functional groups in
pendant/grafted/branched groups. The ester functional groups may be
derived from linear alkyl alcohols with 1 to 40 carbon atoms.
Recent attempts have been made to produce viscosity index improvers
from copolymers of alpha-olefins. However, such viscosity index
improvers remain susceptible to viscosity loss when subjected to
high shear conditions. Low temperature flow, oxidation stability,
deposit control, thickening efficiency, and shear stability are
performance attributes that can be controlled by design. Different
core chemical structures and evolving process technologies enable
design of molecules that deliver varying degrees of performance in
these areas.
[0006] Lubricants capable of performing at lower viscosity (m, for
instance, driveline devices) typically provide increased fuel
economy (thus improving corporate average fuel efficiency (CAFE),
NEDC (European Driving Cycle), or FTP-75 (Federal Test Procedure),
or Japanese test cycle (JC-08)). Conversely, higher viscosity
fluids contribute to elevated gear and transmission operating
temperatures, which are believed to reduce fuel economy and
diminish durability.
[0007] Driveline power transmitting devices such as axles and
transmissions-present highly complex technological challenges for
axle and manual transmission lubricants. These lubricants are
required to ensure hardware durability in the form wear protection
and high load-carrying capacity, while delivering enhanced fuel
efficiency benefits over extended periods. Additionally,
transmissions typically require specific frictional characteristics
of fluids that are compatible with synchronizer material or design.
One of the important parameters influencing performance is
lubricant viscosity. Lubricants capable of performing at lower
viscosity typically provide increased fuel economy. However
viscosity that is too low to maintain sufficient and stable oil
film between surface asperities results in elevated gear and
transmission operating temperatures, which are believed to reduce
fuel economy due to higher friction in contact zones. Therefore,
increasing lubricant viscosity is conventionally believed to
provide better wear protection and durability to gears and
transmissions.
[0008] Consequently, it would be desirable to provide a correctly
balanced lubricant composition to meet the needs of mechanical
devices such as gears and transmissions, especially axle fluids and
manual transmission fluids (MTFs). The discovery of new ways to
control or adjust frictional properties of a lube formulation would
be very beneficial.
[0009] The present disclosure provides solutions and advantages,
which shall become apparent as described below.
SUMMARY
[0010] This disclosure relates in part to a lubricating composition
comprising:
[0011] a first base stock component comprising one or more
metallocene catalyzed polyalphaolefins (mPAOs), each mPAO having a
kinematic viscosity (Kv.sub.100) from 40 cSt to 155 cSt and a
viscosity index (VI) from 150 to 207;
[0012] a second base stock comprising one or more polyalphaolefins
(PAOs), each PAO having a kinematic viscosity (Kv.sub.100) less
than 10 cSt and a VI from 130 to 145; and
[0013] a viscosity modifier comprising a copolymer having units
derived from monomers of (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
esterified with an alcohol;
[0014] wherein at least one of wear control (as determined by ASTM
D4172), load carrying capacity (as determined by ASTM D2783) and
traction reduction (as determined by Mini-Traction Machine (MTM)
Ball-on-Disc apparatus) is improved in a driveline device
lubricated with said lubricating composition as compared to at
least one of wear control, load carrying capacity and traction
reduction achieved with a lubricating composition containing a
viscosity modifier other than said viscosity modifier copolymer, at
an equal or lower kinematic viscosity (Kv@100.degree. C.).
[0015] This disclosure also relates in part to a process for
producing the above lubricating composition, said process
comprising:
[0016] providing a first base stock component comprising one or
more metallocene catalyzed polyalphaolefins (mPAOs), each mPAO
having a kinematic viscosity (Kv.sub.100) from 40 cSt to 155 cSt
and a viscosity index (VI) from 150 to 207;
[0017] providing a second base stock comprising one or more
polyalphaolefins (PAOs), each PAO having a kinematic viscosity
(Kv.sub.100) less than 10 cSt and a VI from 130 to 145;
[0018] providing a viscosity modifier comprising a copolymer having
units derived from monomers of (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
esterified with an alcohol; and
[0019] blending the first base stock component, second base stock
component and viscosity modifier in amounts sufficient to produce
the lubricating composition.
[0020] This disclosure further relates in part to a lubricant
comprising the above lubricating composition, e.g., axle fluids and
manual transmission fluids (MTFs).
[0021] This disclosure yet further relates in part to a method of
lubricating a mechanical device comprising supplying to the device
the above lubricating composition. The mechanical device comprises
a driveline device, e.g., gears or transmissions.
[0022] This disclosure further relates in part to a method for
improving fuel efficiency, while maintaining or improving wear
control, load carrying capacity and/or traction reduction in a
driveline device, e.g., gears or transmissions, lubricated with a
lubricating composition, by using a lubricating composition
comprising: a first base stock component comprising one or more
metallocene catalyzed polyalphaolefins (mPAOs), each mPAO having a
kinematic viscosity (Kv.sub.100) from 40 cSt to 155 cSt and a
viscosity index (VI) from 150 to 207; a second base stock
comprising one or more polyalphaolefins (PAOs), each PAO having a
kinematic viscosity (Kv.sub.100) less than 10 cSt and a VI from 130
to 145; and a viscosity modifier comprising a copolymer having
units derived from monomers of (i) an .alpha.-olefin and (ii) an
ethylenically unsaturated carboxylic acid or derivatives thereof
esterified with an alcohol. In driveline devices such as axles,
higher viscosity fluids can result in lower fuel efficiency due to
churning losses. The internal friction of the fluid measured by its
traction properties is an indicator of its efficiency benefits in
high pressure contact areas within axles. The method of blending of
this disclosure delivers lower traction and lower viscosity
fluids.
[0023] It has been surprisingly found that the lubricating
compositions of this disclosure exhibit improved wear control (as
determined by ASTM D4172), load carrying capacity (as determined by
ASTM D2783) and/or traction reduction (as determined by
Mini-Traction Machine (MTM) Ball-on-Disc apparatus) with said
lubricating composition as compared to wear control, load carrying
capacity and traction reduction achieved, at an equal or lower
kinematic viscosity (Kv@100.degree. C.), with a lubricating
composition containing a viscosity modifier other than a viscosity
modifier comprising a copolymer having units derived from monomers
of (i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof esterified with an
alcohol.
[0024] Further objects, features and advantages of the present
disclosure will be understood by reference to the following
drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 depicts Four-Ball Wear Scar (ASTM D4172) results for
lubricating compositions in Example 1. Consistently lower wear is
achieved by incorporating a viscosity modifier comprising a
copolymer having units derived from monomers of (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with an alcohol.
[0026] FIG. 2 depicts LWI results which are a measure of the
relative ability of a lubricant to prevent wear under applied
loads. LWI is calculated from data obtained from the Four Ball EP
Method (ASTM D2783) in Example 2. Across a broad range of finished
lubricant kinematic viscosity at 100.degree. C. (Kv.sub.100), the
combination of viscosity modifier and mPAO 65 showed surprisingly
higher LWI than either the Meridian VM or the mPAO 65 alone.
[0027] FIG. 3 depicts average friction coefficient measurements for
lubricating compositions in Example 2. The combination of mPAO 65
and Meridian show surprisingly higher friction than other base oil
and/or VM combinations indicating the possibility to control
friction of lubricants designed for automotive transmission
applications such at continuously variable transmissions (CVT) or
infinitely variable transmissions (IVT).
[0028] FIG. 4 depicts average traction coefficient for lubricating
compositions in Example 1. Improved traction coefficients are
observed over a range of finished lubricant kinematic viscosity at
100.degree. C. for these compositions compared to conventional
PIB-based viscosity modifier.
[0029] FIG. 5 is a tabular listing of tapered roller bearing 40-hr
shear stability test results for lubricating compositions in
Example 3.
[0030] FIG. 6 depicts 40-hr shear kinematic viscosity (Kv.sub.100)
loss (%) for lubricating compositions in Example 3. The reduction
in viscosity loss observed with the combination of Meridian and
mPAO 150 compared to either high viscosity component by itself is
unexpected.
[0031] FIG. 7 depicts FZG scuffing testing results for lubricating
compositions in Example 4. Results indicate unexpected directional
improvement in wear protection with higher concentration of
Meridian viscosity modifier even at lower finished fluid
viscosity.
[0032] FIG. 8 depicts thermal oxidation results for lubricating
compositions in Example 4. Oxidation and deposit control in severe
L60-1 test improves with incorporation of Meridian viscosity
modifier.
[0033] FIG. 9 depicts L-42 high speed shock testing results for
lubricating compositions in Example 4.
[0034] FIG. 10 shows the results of 4-Ball Wear Scar (ASTM D4172)
for the designated lubricant compositions (i.e., blends) of Example
1.
[0035] FIG. 11 shows the results of 4-Ball EP (ASTM D2783) load
wear index for the designated lubricant compositions (i.e., blends)
of Example 2.
[0036] FIG. 12 shows the results of High Frequency Reciprocating
Rig (HFRR) friction coefficient for the designated lubricant
compositions (i.e., blends) of Example 2.
DETAILED DESCRIPTION
[0037] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0038] For purposes of this disclosure and the claims thereto, a
polymer is referred to as comprising homopolymers and copolymers,
where copolymers include any polymer having two or more chemically
distinct monomers.
[0039] For the purposes of this disclosure and the claims thereto
the term "polyalphaolefin" or "PAO" includes homopolymers and
copolymers of C.sub.3 or greater alphaolefin monomers.
[0040] The lubricating compositions of this disclosure exhibit
improved wear control (as determined by ASTM D4172), improved load
carrying capacity (as determined by ASTM D2783) and/or improved
traction reduction (as determined by Mini-Traction Machine (MTM)
Ball-on-Disc apparatus) as compared to wear control, load carrying
capacity and traction reduction achieved, at an equal or lower
kinematic viscosity (Kv@100.degree. C.), with a lubricating
composition containing a viscosity modifier other than a viscosity
modifier comprising a copolymer having units derived from monomers
of (i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof esterified with an
alcohol.
[0041] The lubricating compositions of this disclosure are also
capable of providing at least one of improved oxidative stability,
reduced mechanical device operating temperatures, increased
mechanical device durability, improved shear stability, improved
viscosity index, improved low temperature viscometrics and improved
high temperature viscometrics.
[0042] In an embodiment, this disclosure relates to a combination
of a high viscosity synthetic base stock and an ester-containing
viscosity modifier that enables improvement in wear control, load
carrying capacity and traction and provides improved efficiency at
equal or lower kinematic viscosity (Kv @100.degree. C.). Current
high performance commercial axle fluids are blended with low
viscosity synthetic base stocks (such as <10 cSt PAO) in
combination with conventional viscosity modifiers. In axles, higher
viscosity fluids can result in lower fuel efficiency due to
churning losses. The internal friction of the fluid measured by its
traction properties provides an indicator of its efficiency
benefits in high pressure contact areas within axles. The method of
blending a high viscosity synthetic base stock and an
ester-containing viscosity modifier in accordance with this
disclosure provides lower traction and lower viscosity fluids.
[0043] This disclosure relates to lubricating driveline devices,
e.g., gears and transmissions, using the lubricating oils to
improve fuel efficiency without sacrificing driveline device
durability.
Lubricating Oil Base Stocks:
[0044] A wide range of lubricating oils is known in the art.
Lubricating oils that are useful in the present disclosure are both
natural oils and synthetic oils. Natural and synthetic oils (or
mixtures thereof) can be used unrefined, refined, or rerefined (the
latter is also known as reclaimed or reprocessed oil). Unrefined
oils are those obtained directly from a natural or synthetic source
and used without added purification. These include shale oil
obtained directly from retorting operations, petroleum oil obtained
directly from primary distillation, and ester oil obtained directly
from an esterification process. Refined oils are similar to the
oils discussed for unrefined oils except refined oils are subjected
to one or more purification steps to improve the at least one
lubricating oil property. One skilled in the art is familiar with
many purification processes. These processes include solvent
extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as a feed stock.
[0045] Groups I, II, III, IV, V and VI are broad categories of base
oil stocks developed and defined by the American Petroleum
Institute (API Publication 1509; www.API.org) to create guidelines
for lubricant base oils. Group I base stocks generally have a
viscosity index of between 80 to 120 and contain greater than 0.03%
sulfur and less than 90% saturates. Group II base stocks generally
have a viscosity index of between 80 to 120, and contain less than
or equal to 0.03% sulfur and greater than or equal to 90%
saturates. Group III stock generally has a viscosity index greater
than 120 and contains less than or equal to 0.03% sulfur and
greater than 90% saturates. Group IV includes polyalphaolefins
(PAO). Group V base stocks include base stocks not included in
Groups I-IV. The table below summarizes properties of each of these
six groups.
[0046] Group VI are polyinternal olefins ("PIO"). Polyinternal
olefins are long-chain hydrocarbons, typically a linear backbone
with some branching randomly attached; they are obtained by
oligomerization of internal n-olefins. The catalyst is usually a
BF3 complex with a proton source that leads to a cationic
polymerization, or promoted BF3 or AlCl3 catalyst system. The
process to produce polyinternal olefins (PIO) consists of four
steps: reaction, neutralization/washing, hydrogenation and
distillation. These steps are somewhat similar to PAO process. PIO
are typically available in low viscosity grades, 4 cSt, 6 cSt and 8
cSt. If necessary, low viscosity, 1.5 to 3.9 cSt can also be made
conveniently by the BF3 process or other cationic processes.
Typically, the n-olefins used as starting material are
n-C.sub.12-C.sub.18 internal olefins, more preferably,
n-C.sub.14-C.sub.16 olefins are used. PIO can be made with VI and
pour points very similar to PAO, only slightly inferior. They can
be used in engine and industrial lubricant formulations. For more
detailed discussion, see Chapter 2, Polyinternalolefins in the
book, "Synthetics, Mineral Oils, and Bio-Based Lubricants-Chemistry
and Technology" Edited by Leslie R. Rudnick, p. 37-46, published by
CRC Press, Taylor & Francis Group, 2006; or "Polyinternal
Olefins" by Corsico, G.; Mattei, L.; Roselli, A.; Gommellini,
Carlo. EURON, Milan. Italy. Chemical Industries (Dekker) (1999), 77
(Synthetic Lubricants and High-Performance Functional Fluids, (2nd
Edition)), 53-62. Publisher: Marcel Dekker, Inc. PIO was classified
by itself as Group VI fluid in API base stock classification
TABLE-US-00001 Base Stock Properties Viscosity Saturates Sulfur
Index Group I <90 and/or >0.03% and .gtoreq.80 and <120
Group II .gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120
Group III .gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV
Includes polyalphaolefins (PAO) Group V All other base oil stocks
not included in Groups I, II, III or IV Group VI Polyinternal
olefins (PIO)
[0047] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source, for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful in the present
disclosure. Natural oils vary also as to the method used for their
production and purification, for example, their distillation range
and whether they are straight run or cracked, hydrorefined, or
solvent extracted.
[0048] Group II and/or Group III hydroprocessed or hydrocracked
base stocks, as well as synthetic oils such as polyalphaolefins,
alkyl aromatics and synthetic esters, i.e., Group IV and Group V
oils are also well known base stock oils.
[0049] Synthetic oils include hydrocarbon oil such as polymerized
and interpolymerized olefins (polybutylenes, polypropylenes,
propylene isobutylene copolymers, ethylene-olefin copolymers, and
ethylene-alphaolefin copolymers, for example). Polyalphaolefin
(PAO) oil base stocks, the Group IV API base stocks, are a commonly
used synthetic hydrocarbon oil. By way of example, PAOs derived
from C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or mixtures
thereof may be utilized. See U.S. Pat. Nos. 4,956,122; 4,827,064;
and 4,827,073, which are incorporated herein by reference in their
entirety. Group IV oils, that is, the PAO base stocks have
viscosity indices preferably greater than 130, more preferably
greater than 135, still more preferably greater than 140.
[0050] Esters in a minor amount may be useful in the lubricating
oils of this disclosure. Additive solvency and seal compatibility
characteristics may be secured by the use of esters such as the
esters of dibasic acids with monoalkanols and the polyol esters of
monocarboxylic acids. Esters of the former type include, for
example, the esters of dicarboxylic acids such as phthalic acid,
succinic acid, sebacic acid, fumaric acid, adipic acid, linoleic
acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic acid,
etc., with a variety of alcohols such as butyl alcohol, hexyl
alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, etc. Specific
examples of these types of esters include dibutyl adipate,
di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl
phthalate, dieicosyl sebacate, etc.
[0051] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols such as the neopentyl polyols; e.g., neopentyl
glycol, trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol,
trimethylol propane, pentaerythritol and dipentaerythritol with
alkanoic acids containing at least 4 carbon atoms, preferably
C.sub.5 to C.sub.30 acids such as saturated straight chain fatty
acids including caprylic acid, capric acids, lauric acid, myristic
acid, palmitic acid, stearic acid, arachic acid, and behenic acid,
or the corresponding branched chain fatty acids or unsaturated
fatty acids such as oleic acid, or mixtures of any of these
materials.
[0052] Esters should be used in an amount such that the improved
wear and corrosion resistance provided by the lubricating oils of
this disclosure are not adversely affected. The esters preferably
have a D5293 viscosity of less than 10,000 cP at -35.degree. C.
[0053] Non-conventional or unconventional base stocks and/or base
oils include one or a mixture of base stock(s) and/or base oil(s)
derived from: (1) one or more Gas-to-Liquids (GTL) materials, as
well as (2) hydrodewaxed, or hydroisomerized/cat (and/or solvent)
dewaxed base stock(s) and/or base oils derived from synthetic wax,
natural wax or waxy feeds, mineral and/or non-mineral oil waxy feed
stocks such as gas oils, slack waxes (derived from the solvent
dewaxing of natural oils, mineral oils or synthetic oils; e.g.,
Fischer-Tropsch feed stocks), natural waxes, and waxy stocks such
as gas oils, waxy fuels hydrocracker bottoms, waxy raffinate,
hydrocrackate, thermal crackates, foots oil or other mineral,
mineral oil, or even non-petroleum oil derived waxy materials such
as waxy materials recovered from coal liquefaction or shale oil,
linear or branched hydrocarbyl compounds with carbon number of 20
or greater, preferably 30 or greater and mixtures of such base
stocks and/or base oils.
[0054] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds and/or elements as feed
stocks such as hydrogen, carbon dioxide, carbon monoxide, water,
methane, ethane, ethylene, acetylene, propane, propylene, propyne,
butane, butylenes, and butynes. GTL base stocks and/or base oils
are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons; for example, waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feed stocks. GTL base stock(s) and/or base oil(s)
include oils boiling in the lube oil boiling range (1)
separated/fractionated from synthesized GTL materials such as, for
example, by distillation and subsequently subjected to a final wax
processing step which involves either or both of a catalytic
dewaxing process, or a solvent dewaxing process, to produce lube
oils of reduced/low pour point; (2) synthesized wax isomerates,
comprising, for example, hydrodewaxed or hydroisomerized cat and/or
solvent dewaxed synthesized wax or waxy hydrocarbons; (3)
hydrodewaxed or hydroisomerized cat and/or solvent dewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates); preferably
hydrodewaxed or hydroisomerized/followed by cat and/or solvent
dewaxing dewaxed F-T waxy hydrocarbons, or hydrodewaxed or
hydroisomerized/followed by cat (or solvent) dewaxing dewaxed, F-T
waxes, or mixtures thereof.
[0055] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from 2 mm.sup.2/s to 50 mm.sup.2/s (ASTM D445).
They are further characterized typically as having pour points of
-5.degree. C. to -40.degree. C. or lower (ASTM D97). They are also
characterized typically as having viscosity indices of 80 to 140 or
greater (ASTM D2270).
[0056] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) typically have very low sulfur and
nitrogen content, generally containing less than 10 ppm, and more
typically less than 5 ppm of each of these elements. The sulfur and
nitrogen content of GTL base stock(s) and/or base oil(s) obtained
from F-T material, especially F-T wax, is essentially nil. In
addition, the absence of phosphorous and aromatics make this
materially especially suitable for the formulation of low SAP
products.
[0057] The term GTL base stock and/or base oil and/or wax isomerate
base stock and/or base oil is to be understood as embracing
individual fractions of such materials of wide viscosity range as
recovered in the production process, mixtures of two or more of
such fractions, as well as mixtures of one or two or more low
viscosity fractions with one, two or more higher viscosity
fractions to produce a blend wherein the blend exhibits a target
kinematic viscosity.
[0058] The GTL material, from which the GTL base stock(s) and/or
base oil(s) is/are derived is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0059] Base oils for use in the formulated lubricating oils useful
in the present disclosure are any of the variety of oils
corresponding to API Group 1, Group II, Group III, Group IV, Group
V and Group VI oils and mixtures thereof, preferably API Group II,
Group III, Group IV, Group V and Group VI oils and mixtures
thereof, more preferably the Group III to Group VI base oils due to
their exceptional volatility, stability, viscometric and
cleanliness features. Minor quantities of Group I stock, such as
the amount used to dilute additives for blending into formulated
lube oil products, can be tolerated but should be kept to a
minimum, i.e. amounts only associated with their use as
diluent/carrier oil for additives used on an "as-received" basis.
Even in regard to the Group II stocks, it is preferred that the
Group II stock be in the higher quality range associated with that
stock, i.e. a Group II stock having a viscosity index in the range
100<VI<120.
[0060] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) and hydrodewaxed, or
hydroisomerized/cat (and/or solvent) dewaxed base stock(s) and/or
base oil(s) typically have very low sulfur and nitrogen content,
generally containing less than 10 ppm, and more typically less than
5 ppm of each of these elements. The sulfur and nitrogen content of
GTL base stock(s) and/or base oil(s) obtained from F-T material,
especially F-T wax, is essentially nil. In addition, the absence of
phosphorous and aromatics make this material especially suitable
for the formulation of low sulfur, sulfated ash, and phosphorus
(low SAP) products.
[0061] Polyalphaolefins (PAOs) are preferred lubricating oil
basestocks of this disclosure. The PAOs can preferably comprise one
or more C.sub.8 to C.sub.12 monomers. The PAOs have a viscosity
(Kv.sub.100) from 2 to 700 cSt at 100.degree. C., preferably from 3
to 155 cSt at 100.degree. C., and more preferably from 4 to 150 cSt
at 100.degree. C.; and a viscosity index (VI) from 130 to 207,
preferably from 140 to 200, and more preferably from 150 to 197. As
used herein, viscosity (Kv.sub.100) is determined by ASTM D 445-01,
and viscosity index (VI) is determined by ASTM D 2270-93
(1998).
[0062] The PAOs useful in this disclosure can have a pour point
(PP) less than -25.degree. C.; a molecular weight distribution
(Mw/Mn) less than 2.0; and a glass transition temperature Tg less
than -60.degree. C.
[0063] In another embodiment according to the present disclosure,
any PAO described herein may have a kinematic viscosity (Kv) at
100.degree. C. in any of the following ranges: from 65 to 1,000
cSt, from 100 to 950 cSt, from 250 cSt to 900 cSt, from 400 cSt to
800 cSt, wherein all values are measured by ASTM D445-01.
[0064] The PAOs useful in this disclosure have a high viscosity
index and a Kv.sub.100 of 2 cSt or more, alternatively 3 cSt or
more, alternatively 4 cSt or more, up to 700 cSt, with a VI of 130
or more, alternatively 140 or more, alternatively 150 or more.
Usually base stock VI is a function of fluid viscosity. Usually,
the higher the VI, the better it is for lube application. Base
stock VI also depends on feed composition. Fluids made from single
1-octene, 1-nonene, 1-decene, or 1-dodecene have excellent VI and
good low pour point. Fluids made from two or more olefins selected
from C.sub.8 to C.sub.12 alphaolefins generally have excellent high
VI and superior low pour points if the average carbon chain length
of feed LAOs is kept within 8 to 12 carbons. A relatively much
lower average chain length in the feed (much below 6 carbons) of
the mixed LAO would result in lower VI. Too high of a average chain
length in the feed (much above 12 carbons) of the mixed LAO would
result in very high pour point, around room temperature.
[0065] The viscosity-temperature relationship of lubricating oil is
one of the critical criteria which must be considered when
selecting a lubricant for a particular application. Viscosity Index
(VI) is an empirical, unitless number which indicates the rate of
change in the viscosity of an oil within a given temperature range
and is related to kinematic viscosities measured at 40.degree. C.
and 100.degree. C. (typically using ASTM Method D 445). Fluids
exhibiting a relatively large change in viscosity with temperature
are said to have a low viscosity index. The low VI oil, for
example, will thin out at elevated temperatures faster than the
high VI oil. Usually, the high VI oil is more desirable because it
has higher viscosity at higher temperature, which translates into
better or thicker lubrication film and better protection of the
contacting machine elements. As the oil operating temperature
decreases, the viscosity of the high VI oil will not increase as
much as the viscosity of low VI oil. This is advantageous because
the excessive high viscosity of the low VI oil will decrease the
efficiency of the operating machine. Thus high VI oil has
performance advantages in both high and low temperature
operation.
[0066] The PAOs useful in this disclosure have low pour points (PP)
less than -25.degree. C. preferably less than -30.degree. C., and
more preferably less than -35.degree. C. As used herein, pour point
is determined by ASTM D97.
[0067] In an embodiment of this disclosure, any PAO described
herein may have a pour point of less than -25.degree. C. (as
measured by ASTM D97), preferably less than -35.degree. C.,
preferably less than -45.degree. C., preferably less than
-55.degree. C., preferably less than -65.degree. C., and preferably
between -25.degree. C. and -75.degree. C.
[0068] The PAOs useful in this disclosure have a narrow molecular
weight distribution (Mw/Mn) less than 2.0, preferably less than
1.95, and more preferably less than 1.9 as synthesized. As used
herein, molecular weight distribution (Mw/Mn) is determined by GPC
using a column for medium to low molecular weight polymers,
tetrahydrofuran as solvent and polystyrene as calibration
standard.
[0069] The PAOs useful in this disclosure have a Mw of 100,000
g/mol or less, or between 2000 and 80,000 g/mol, or between 2500
and 60,000 g/mol, or between 2800 and 50,000 g/mol, or between 3360
and 40,000 g/mol. Preferred Mw's include those from 840 to 55,100
g/mol, or from 900 to 45,000 g/mol, or 1000 to 40,000 g/mol, or
2,000 to 37,500 g/mol. Alternatively preferred Mw's include 2240 to
67900 g/mol and 2240 to 37200 g/mol.
[0070] The PAOs useful in this disclosure preferably have an Mn of
50,000 g/mol or less, or 40,000 g/mol or less, or between 2000 and
40,000 g/mol, or between 2500 and 30,000 g/mol, preferably between
5000 and 20,000 g/mol. Preferred Mn ranges include those from 2800
to 10,000 g/mol or from 2800 to 8.000 g/mol. Alternatively
preferred Mn ranges are from 2000 to 20,900 g/mol, or 2800 to
20,000 g/mol, or 2000 to 17000 g/mol, or 2000 to 12000 g/mol, or
2800 to 29000 g/mol, or 2800 to 17000 g/mol, or 2000 to 5000
g/mol.
[0071] The Mw and Mn are measured by GPC using a column for medium
to low molecular weight polymers, tetrahydrofuran as solvent and
polystyrene as calibration standard, correlated with the fluid
viscosity according to a power equation.
[0072] In another embodiment, the PAOs described herein have a
narrow molecular weight distribution of greater than 1 and less
than 2, alternatively less than 1.95, alternatively less than 1.90,
alternatively less than 1.85. The Mn and Mw are measured by gel
permeation chromatography (GPC) using a column for medium to low
molecular weight polymers, tetrahydrofuran as solvent and narrow
molecular weight distribution polystyrene as calibration standard,
correlated with the fluid viscosity according to a power equation.
The MWD of PAO is a function of fluid viscosity. Alternatively any
of the polyalphaolefins described herein preferably have an Mw/Mn
of between 1 and 2.0, alternatively between 1 and 1.95, depending
on fluid viscosity.
[0073] The PAOs useful in this disclosure have low glass transition
temperature T, less than -60.degree. C., preferably less than
-70.degree. C., and more preferably less than -80.degree. C. As
used herein, glass transition temperature T.sub.g is determined by
differential scanning calorimetry (DSC). The polyolefin products
produced in accordance with the process of this disclosure have no
crystallization peak as measured by differential scanning
calorimetry and high thermal stability.
[0074] The PAOs useful in this disclosure can comprise a single
alphaolefin monomer type, or may comprise two or more different
alphaolefin monomers. In one embodiment, this disclosure relates to
PAOs comprising a molar amount of C.sub.8 to C.sub.12 alphaolefin
monomers selected from the group consisting of 55 mol % or more, 60
mol % or more, 65 mol % or more, 70 mol % or more, 75 mol % or
more, 80 mol % or more, 85 mol % or more, 90 mol % or more, 95 mol
% or more, 100 mol %, all based on the total moles of monomers
present in the polyalphaolefin, as measured by .sup.13C NMR. When
two or more alphaolefin monomers are present, it is sometimes
desirable to add propylene, or butene (typically 1-butene) olefins
into the feed. Use of these smaller olefins in the feed offers the
advantage of lower feed cost and/or more abundant feed source. When
adding C.sub.3 or 1-C.sub.4 olefins as one of the feed components,
it is important to maintain the total average carbon chain length
of the feed LAO (linear alphaolefin) between 8 to 12 carbons.
[0075] In one or more embodiments, the PAOs comprise polymers of
one or more alphaolefins (also known as 1-olefins) with carbon
numbers of C.sub.8 to C.sub.12. Preferably, at least one of the
alphaolefins is a linear alphaolefin (LAO); more preferably, all
the alphaolefins are LAOS. Suitable LAOs include 1-octene,
1-nonene, 1-decene, 1-undecene, and 1-dodecene, and blends
thereof.
[0076] In one or more embodiments, the PAO comprises polymers of
two or more C.sub.8 to C.sub.12 LAOs to make `copolymer` or
`terpolymer` or higher-order copolymer combinations. Other
embodiments involve polymerization of a mixture of LAOs selected
from C.sub.8 to C.sub.12 LAOs with even carbon numbers, preferably
a mixture of two or three LAOs selected from 1-octene, 1-decene,
and 1-dodecene.
[0077] In one or more embodiments, the PAO comprises polymers of a
single alphaolefin species having a total carbon count of 8 to 12.
In other embodiments, the PAO comprises polymers of mixed (i.e.,
two or more) alphaolefin species, wherein each alphaolefin species
has a carbon number of 8 to 12. In other embodiments, the PAO
comprises polymers of mixed alphaolefin species wherein the
molar-average carbon number ("C.sub.LAO") is 8 to 12 or 9 to
11.
[0078] In another embodiment according to the present disclosure,
any PAO described herein may have a density of 0.75 to 0.96
g/cm.sup.3, preferably 0.80 to 0.94 g/cm.sup.3, alternatively from
0.76 to 0.855 g/cm.sup.3.
[0079] The high viscosity PAOs useful in this disclosure are
desirable for use as lubricating oil base stocks and also blend
stocks with API Groups I to V or gas-to-liquid (GTL) derived lube
base stocks for use in industrial and automotive engine or gear
oil, especially certain high Kv.sub.100 grades of 65 to 155 cSt
which are especially desirable for use as lubricating oil base
stocks or blend stocks with Groups I to V or GTL-derived lube base
stocks for use in industrial and automotive engine or gear oil.
[0080] These higher viscosity PAOs can be used as lubricating oil
base stocks and also superior blend stocks. They can be blend
stocks with any of the API Group I to V and GTL fluids to give the
optimum viscometrics, solvency, high and low temperature lubricity,
etc. The PAOs can be further blended with proper additives,
including antioxidants, antiwear additives, friction modifiers,
dispersants, detergents, corrosion inhibitors, defoamants, extreme
pressure additives, seal swell additives, and optionally viscosity
modifiers, etc. Description of typical additives can be found in
the book "Lubricant Additives: Chemistry and Applications," L. R.
Rudnick, ed. Marcel Dekker Inc., New York, 2001.
[0081] The PAOs can be produced by conventional methods known in
the art. The preferred high viscosity PAOs used in this disclosure
can be prepared from different feed olefins using metallocene
catalysts. The metallocene catalyst system, products, process and
feeds are described, for example, in U.S. Application Publication
No. 2011/0136714.
[0082] The basestock component of the present lubricating oils will
typically be from 80 to 99 weight percent of the total composition
(all proportions and percentages set out in this specification are
by weight unless the contrary is stated) and more usually in the
range of 90 to 99 weight percent.
Viscosity Modifiers:
[0083] The viscosity modifiers useful in the lubricating
compositions of the disclosure include substantially linear
polymers with a weight average molecular weight of 45,000 or less,
or 35,000 or less, or 25,000 or less, or 8000 to 25,000, or 12,000
to 20,000.
[0084] The substantially linear polymers may be copolymers
comprising units derived from monomers (i) an .alpha.-olefin and
(ii) an ethylenically unsaturated carboxylic acid or derivatives
thereof esterified with an alcohol. In one embodiment, the
substantially linear polymer may be a copolymer comprising units
derived from monomers (i) one or more alpha olefins and (ii) one or
more alkyl (meth)acrylate esters. The ethylenically unsaturated
carboxylic acid may be esterified with alcohol before or after
polymerization with the .alpha.-olefin. In one embodiment the
ethylenically unsaturated carboxylic acid may be esterified with
alcohol before polymerization with the .alpha.-olefin. In one
embodiment the ethylenically unsaturated carboxylic acid may be
esterified with alcohol after polymerization with the
.alpha.-olefin.
[0085] A commercially available copolymer prepared by
esterification before polymerization is available from Akzo Nobel
sold under the tradename Ketjenlube.RTM.3700. The alcohol may have
1 to 40, or 1 to 30, or 4 to 20, or 6 to 16 carbon atoms. Examples
of a suitable alcohol include 2-ethylhexanol, 2-butyloctanol,
2-hexyldecanol, 2-octyldodecanol, 2-decyltetradecanol, butanol,
pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol,
dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol,
heptadecanol, octadecanol, eicosanol, or mixtures thereof. A
copolymer of this type is described in more detail in U.S. Pat.
Nos. 4,526,950, 6,419,714, 6,573.224, or 6,174,843.
[0086] The ethylenically unsaturated carboxylic acid may be
esterified with alcohol after polymerization with the
.alpha.-olefin. A copolymer of this type may be a substantially
linear polymer that may in one embodiment be (a) a copolymer
comprising units derived from monomers (i) an .alpha.-olefin and
(ii) an ethylenically unsaturated carboxylic acid or derivatives
thereof esterified with a primary alcohol branched at the .beta.-
or higher position, wherein the copolymer typically has a reduced
specific viscosity of up to 0.2, (b) a poly(meth)acrylate, or
mixtures thereof.
[0087] The substantially linear polymer may be present in the
lubricating compositions described herein at 0.1 wt % to 50 wt %,
or 2 wt % to 40 wt %, or 5 wt % to 30 wt %, or 8 wt % to 20 wt % of
the lubricating composition. In certain embodiments the lubricating
composition contains 65 to 99 wt % of synthetic base stock and 1 to
35 wt % of substantially linear polymer. In other embodiments, the
lubricating composition contains 75 to 98 wt % of synthetic base
stock and 2 to 25 wt % of substantially linear polymer.
[0088] In one embodiment, the substantially linear polymer may be a
copolymer comprising units derived from monomers (i) one or more
alpha olefins and (ii) one or more alkyl (meth)acrylate esters. In
another embodiment the substantially linear polymer includes a
mixtures of (a) a copolymer comprising units derived from monomers
of (i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof esterified with a primary
alcohol, and (b) a poly(meth)acrylate.
[0089] The poly(meth)acrylate (typically a polymethacrylate) can
have units derived from a mixture of alkyl (meth)acrylate ester
monomers containing (a) 8 to 24, or 12 to 18, or to 15 carbon atoms
in the alcohol-derived portion of the ester group and (b) 6 to 11,
or 8 to 11, or 8 carbon atoms in the alcohol-derived portion of the
ester group, and which have 2-(C.sub.1-4 alkyl)-substituents, and
optionally, at least one monomer selected from the group consisting
of (meth)acrylic acid esters containing 1 to 7 carbon atoms in the
alcohol-derived portion of the ester group and which are different
from (meth)acrylic acid esters (a) and (b), vinyl aromatic
compounds (or vinyl aromatic monomers); and nitrogen-containing
vinyl monomers; provided that no more than 60% by weight, or no
more than 50% by weight, or no more than 35% by weight of the
esters contain not more than 10 carbon atoms in the alcohol-derived
portion of the ester group. The linear polymer of this type is
described in more detail in U.S. Pat. No. 6,124,249 or EP 0 937 769
A1. The "alcohol-derived portion" refers to the "--OR" portion of
an ester, when written as R'C(=0)-OR, whether or not it is actually
prepared by reaction with an alcohol. Optionally, the linear
polymer may further contain a third monomer. The third monomer may
be styrene, or mixtures thereof. The third monomer may be present
in an amount 0% to 25% of the polymer composition, or from 1% to
15% of the composition, 2% to 10% of the composition, or even from
1% to 3% of the composition.
[0090] Typically, the mole ratio of esters (a) to esters (b) in the
copolymer ranges from 95:5 to 35:65, or 90:10 to 60:40, or 80:20 to
50:50.
[0091] The esters are usually aliphatic esters, typically alkyl
esters. In one embodiment the ester of (a) may be a C.sub.12-15
alkyl methacrylate and the ester of (b) may be 2-ethylhexyl
methacrylate.
[0092] In one embodiment, the ester groups in ester (a) contain
branched alkyl groups. The ester groups may contain 2 to 65%, or 5
to 60% or greater of the ester groups having branched alkyl
groups.
[0093] The C.sub.1-4 alkyl substituents may be methyl, ethyl, and
any isomers of propyl and butyl.
[0094] The weight average molecular weight of the
poly(meth)acrylate may be 45,000 or less, or 35,000 or less, or
25,000 or less, or 8000 to 25,000, or 12,000 to 20,000.
[0095] In one embodiment the substantially linear polymer includes
a copolymer comprising units derived from monomers (i) an
.alpha.-olefin and (ii) an ethylenically unsaturated carboxylic
acid or derivatives thereof esterified with a primary alcohol
branched at the .beta.- or higher position, wherein the copolymer
typically has a reduced specific viscosity of up to 0.2, or up to
0.15, or up to 0.10, or up to 0.08. In one embodiment the reduced
specific viscosity may be up to 0.08 (or 0.02 to 0.08 (or 0.02 to
0.07, 0.03 to 0.07 or 0.04 to 0.06).
[0096] A measurement correlating with molecular weight of the
copolymer (or interpolymer such as an alternating copolymer) may be
expressed in terms of the "reduced specific viscosity" of the
copolymer which is a recognized means of expressing the molecular
size of a polymeric substance. As used herein, the reduced specific
viscosity (abbreviated as RSV) is the value typically obtained in
accordance with the formula RSV=(Relative
Viscosity-1)/Concentration, wherein the relative viscosity is
determined by measuring, by means of a dilution viscometer, the
viscosity of a solution of 1.6 g of the polymer in 100 cm.sup.3 of
acetone and the viscosity of acetone at 30.degree. C. For purpose
of computation by the above formula, the concentration is adjusted
to 1.6 g of the copolymer per 100 cm.sup.3 of acetone. A more
detailed discussion of the reduced specific viscosity, also known
as the specific viscosity, as well as its relationship to the
average molecular weight of a copolymer, appears in Paul J. Flory,
Principles of Polymer Chemistry, (1953 Edition) pages 308 et
seq.
[0097] In one embodiment the copolymer may be derived from monomers
(i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof,
[0098] wherein 0.1 to 99.89% of the carboxylic acid units are
esterified with a primary alcohol branched at the .beta.- or higher
position,
[0099] wherein 0.1 to 99.89% of the carboxylic acid units are
esterified with a linear alcohol or an alpha-branched alcohol
(e.g., a secondary alcohol),
[0100] wherein 0.01 to 10% of the carboxylic acid units has at
least one of an amino-, amido- and/or imido-group, and
[0101] wherein the copolymer has a reduced specific viscosity
(prior to esterification) of up to 0.08.
[0102] In one embodiment the copolymer may be derived from monomers
(i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof,
[0103] wherein 0.1 to 99.89% of the carboxylic acid units are
esterified with a primary alcohol branched at the .beta.- or higher
position,
[0104] wherein 0.1 to 99.9% of the carboxylic acid units are
esterified with a linear alcohol or an alpha-branched alcohol,
[0105] wherein 0 to 10% of the carboxylic acid units has at least
one of an amino-, amido- and/or imido-group, and
[0106] wherein the copolymer has a reduced specific viscosity of up
to 0.08.
[0107] A linear alcohol may include methanol, ethanol, propanol,
butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol,
undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol,
hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, or
mixtures thereof. In one embodiment the linear alcohol contains 6
to 30, or 8 to 20, or 8 to 15 carbon atoms (typically 8 to 15
carbon atoms).
[0108] The linear alcohol may include commercially available
materials such as Oxo Alcohol.RTM. 7911, Oxo Alcohol.RTM. 7900 and
Oxo Alcohol.RTM. 1 100 of Monsanto; Alphanol.RTM. 79 of ICI;
Nafol.RTM. 1620, Alfol.RTM. 610 and Alfol.RTM. 810 of Condea (now
Sasol); Epal.RTM. 610 and Epal.RTM. 810 of Ethyl Corporation (now
Afton); Linevol.RTM. 79, Linevol.RTM. 91 1 and Dobanol.RTM. 25 L of
Shell AG; Lial.RTM. 125 of Condea Augusta, Milan; Dehydad.RTM. and
Lorol.RTM. of Henkel KGaA (now Cognis) as well as Linopol.RTM. 7-1
1 and Acropol.RTM. 91 of Ugine Kuhlmann.
[0109] In one embodiment the copolymer may be derived from monomers
of (i) an .alpha.-olefin and (ii) an ethylenically unsaturated
carboxylic acid or derivatives thereof,
[0110] wherein 5 to 15% of the carboxylic acid units are esterified
with a primary alcohol branched at the .beta.- or higher
position,
[0111] wherein 0.1 to 95% of the carboxylic acid units are
esterified with a linear alcohol or an alpha-branched alcohol,
[0112] wherein 0 to less than 2% of the carboxylic acid units has
at least one of an amino-, amido- and/or imido-group, and
[0113] wherein the copolymer has a reduced specific viscosity of up
to 0.08.
[0114] In one embodiment the copolymer comprises units derived from
monomers (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof esterified with
a primary alcohol branched at the .beta.- or higher position. In
certain embodiments the copolymer may be represented by the formula
below. Ester or other groups with the primary alcohol-derived
moiety branched at the .beta.- or higher position may be
represented within the ( ).sub.w shown in the formula:
##STR00001##
wherein
[0115] Formula (I) may comprise a copolymer backbone (BB), and one
or more pendant groups as shown, wherein BB may be derived from a
copolymer of (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof (typically
fumaric acid, maleic anhydride, maleic acid, (meth)acrylic acid,
itaconic anhydride or itaconic acid);
[0116] X may be a functional group which either (i) contains a
carbon and at least one oxygen or nitrogen atom (such as an ester
or amide, or imide linkage), 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, (typically X may be a functional group which either (i)
contains a carbon and at least one oxygen or nitrogen atom);
[0117] w may be the number of pendant groups attached to the
copolymer backbone, which may be in the range of 2 to 2000, or 2 to
500, or 5 to 250;
[0118] y may be 0, 1, 2 or 3, provided that in at least 1 mol % of
the pendant 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;
[0119] p may be an integer in the range of 1 to 15 (or 1 to 8, or 1
to 4); and
[0120] R' and R'' may independently be linear or branched
hydrocarbyl groups, and the combined total number of carbon atoms
present in R' and R'' may be at least 12 (or at least 16, or at
least 18 or at least 20).
[0121] In different embodiments the copolymer with pendant groups
may contain 0.10% to 100%, or 0.5% to 20%, or 0.75% to 10%,
branched hydrocarbyl groups represented by a group within ( ).sub.y
of the formula (I) above, expressed as a percentage of the total
number of pendant groups. The pendant groups of formula (1) may
also be used to define the ester groups as defined above by the
phrase "esterified with a primary alcohol branched at the .beta.-
or higher position".
[0122] In different embodiments the functional groups defined by X
on the formula 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.
[0123] In one embodiment X may be derived from an ethylenically
unsaturated carboxylic 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 ethylenically
unsaturated carboxylic acid or derivatives thereof may be at least
one of maleic anhydride or maleic acid.
[0124] In one embodiment X is other than an alkylene group,
connecting the copolymer backbone and the branched hydrocarbyl
groups.
[0125] In different embodiments the pendant groups may be
esterified, amidated or imidated functional groups.
[0126] In one embodiment the pendant groups may be derived from
esterified and/or amidated functional groups.
[0127] In one embodiment the copolymer includes esterified pendant
groups. The pendant groups may be derived from Guerbet alcohols.
The Guerbet alcohols may contain 10 to 60, or 12 to 60, or 16 to 40
carbon atoms. In one embodiment the primary alcohol branched at the
.beta.- or higher position described herein may be a Guerbet
alcohol. Methods to prepare Guerbet alcohols are disclosed in U.S.
Pat. No. 4,767,815.
[0128] Examples of suitable groups for R' and R'' on the formula
defined above include the following:
[0129] 1) 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);
[0130] 2) 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);
[0131] 3) 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);
[0132] 4) 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
group);
[0133] 5) alkyl groups containing C.sub.1-5 polymethylene groups,
such as 2-(3-methylhexyl)-7-methyl-decyl and
2-(1,4-dimethylbutyl)-5,7,7-trimethyl-octyl groups; and
[0134] 6) 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, iso-butene oligomers (from pentamer to
octamer), C.sub.5-17 .alpha.-olefin oligomers (from dimer to
hexamer).
[0135] The pendant groups may contain a total combined number of
carbon atoms on R' and R'' in the range of 12 to 60, or 14 to 50,
or 16 to 40, or 18 to 40, or 20 to 36.
[0136] Each of R' and R'' 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' and R'' group may be 10 to
24.
[0137] Examples of suitable primary alcohol branched at the 3- or
higher position include 2-ethylhexanol, 2-propyl heptanol,
2-butyloctanol, 2-hexyldecanol, 2-octyldodecanol,
2-decyltetradecanol, or mixtures thereof.
[0138] The ethylenically unsaturated carboxylic acid or derivatives
thereof may be an acid or anhydride or derivatives thereof that may
be wholly esterified, partially esterified or mixtures thereof.
When partially esterified, other functional groups include acids,
salts or mixtures thereof. Suitable salts include alkali metals,
alkaline earth metals or mixtures thereof. The salts include
lithium, sodium, potassium, magnesium, calcium or mixtures thereof.
The unsaturated carboxylic acid or derivatives thereof includes
acrylic acid, methyl acrylate, methacrylic acid, maleic acid or
anhydride, fumaric acid, itaconic acid or anhydride or mixtures
thereof, or substituted equivalents thereof.
[0139] Suitable examples of the ethylenically unsaturated
carboxylic acid or derivatives thereof include itaconic anhydride,
maleic anhydride, methyl maleic anhydride, ethyl maleic anhydride,
dimethyl maleic anhydride or mixtures thereof.
[0140] In one embodiment the ethylenically unsaturated carboxylic
acid or derivatives thereof includes maleic anhydride or
derivatives thereof.
[0141] Examples of an alpha-olefin include 1-decene, 1-undecene,
1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-hepta-decene 1-octadecene, or mixtures thereof. An
example of a useful alpha-olefin is 1-dodecene. The alpha-olefin
may be a branched alpha-olefin, or mixtures thereof. If the
.alpha.-olefin is branched, the number of carbon atoms of the
.alpha.-olefin may range from 4 to 32, or 6 to 20, or 8 to 16.
[0142] In one embodiment the copolymer of the disclosure further
includes a nitrogen containing group such as those disclosed above.
The nitrogen containing group may be derived from a nitrogen
containing compound capable of being incorporated during
copolymerization. In one embodiment the copolymer of the disclosure
further includes a nitrogen containing group that may be capable of
reacting with the functionalized copolymer backbone, typically for
capping the copolymer backbone. The capping may result in the
copolymer having ester, amide, imide or amine groups. The nitrogen
group is described in more detail in PCT Patent Application No.
PCT/US09/052,028.
[0143] In one embodiment the copolymer comprises units derived from
monomers (i) an .alpha.-olefin and (ii) an ethylenically
unsaturated carboxylic acid or derivatives thereof may be further
reacted with an amine to additionally provide oxidation control.
Typically, the copolymer with oxidation control contains an
incorporated residue of an amine-containing compound such as
morpholines, pyrrolidinones, imidazolidinones, acetamides,
.beta.-alanine alkyl esters, or 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.
[0144] In one embodiment the compounds based on imidazolidinones,
cyclic carbamates or pyrrolidinones may be derived from a compound
of general structure:
##STR00002##
wherein:
X=--OH or NH.sub.2;
[0145] Hy'' may be hydrogen, or a hydrocarbyl group (typically
alkyl, or C.sub.1-4-, or C.sub.2- alkyl); Hy may be a
hydrocarbylene group (typically alkylene, or C.sub.1-4-, or
C.sub.2- alkylene); Q=>NH, >NR, >CH.sub.2, >CHR,
>CR.sub.2, or --O-- (typically >NH, or >NR) and R may be
C.sub.1-4 alkyl.
[0146] 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.
[0147] In one embodiment the copolymer may be reacted with an
amine-containing compound selected from morpholines,
imidazolidinones, and mixtures thereof.
[0148] Other illustrative copolymers and interpolymers useful as
viscosity modifiers of this disclosure are described, for example,
in U.S. Patent Application Publication Nos. 2010/0144566 and
2011/0190182, and also WO 2011/066242, the disclosures of which are
incorporated herein in their entirety.
Other Additives:
[0149] The formulated lubricating oil useful in the present
disclosure may additionally contain one or more of the other
commonly used lubricating oil performance additives including but
not limited to dispersants, other detergents, corrosion inhibitors,
rust inhibitors, metal deactivators, other antiwear agents and/or
extreme pressure additives, anti-seizure agents, wax modifiers,
viscosity index improvers, fluid-loss additives, seal compatibility
agents, other friction modifiers, lubricity agents, anti-staining
agents, chromophoric agents, defoamants, demulsifiers, emulsifiers,
densifiers, wetting agents, gelling agents, tackiness agents,
colorants, and others. For a review of many commonly used
additives, see Klamann in Lubricants and Related Products, Verlag
Chemie, Deerfield Beach, Fla.; ISBN 0-89573-177-0. Reference is
also made to "Lubricant Additives" by M. W. Ranney, published by
Noyes Data Corporation of Parkridge, N.J. (1973).
[0150] The types and quantities of performance additives used in
combination with the instant disclosure in lubricant compositions
are not limited by the examples shown herein as illustrations.
Antioxidants
[0151] Typical antioxidant include phenolic antioxidants, aminic
antioxidants and oil-soluble copper complexes.
[0152] The phenolic antioxidants include sulfurized and
non-sulfurized phenolic antioxidants. The terms "phenolic type" or
"phenolic antioxidant" used herein includes compounds having one or
more than one hydroxyl group bound to an aromatic ring which may
itself be mononuclear, e.g., benzyl, or poly-nuclear, e.g.,
naphthyl and spiro aromatic compounds. Thus "phenol type" includes
phenol per se, catechol, resorcinol, hydroquinone, naphthol, etc.,
as well as alkyl or alkenyl and sulfurized alkyl or alkenyl
derivatives thereof, and bisphenol type compounds including such
bi-phenol compounds linked by alkylene bridges sulfuric bridges or
oxygen bridges. Alkyl phenols include mono- and poly-alkyl or
alkenyl phenols, the alkyl or alkenyl group containing from 3-100
carbons, preferably 4 to 50 carbons and sulfurized derivatives
thereof, the number of alkyl or alkenyl groups present in the
aromatic ring ranging from 1 to up to the available unsatisfied
valences of the aromatic ring remaining after counting the number
of hydroxyl groups bound to the aromatic ring.
[0153] Generally, therefore, the phenolic anti-oxidant may be
represented by the general formula:
(R).sub.x--Ar--(OH).sub.y
where Ar is selected from the group consisting of:
##STR00003##
wherein R is a C.sub.3-C.sub.100 alkyl or alkenyl group, a sulfur
substituted alkyl or alkenyl group, preferably a C.sub.4-C.sub.50
alkyl or alkenyl group or sulfur substituted alkyl or alkenyl
group, more preferably C.sub.3-C.sub.100 too alkyl or sulfur
substituted alkyl group, most preferably a C.sub.4-C.sub.50 alkyl
group, R.sup.g is a C.sub.1-C.sub.100 alkylene or sulfur
substituted alkylene group, preferably a C.sub.2-C.sub.50 alkylene
or sulfur substituted alkylene group, more preferably a
C.sub.2-C.sub.2 alkylene sulfur substituted alkylene group, y is at
least 1 to up to the available valences of Ar, x ranges from 0 to
up to the available valances of Ar-y, z ranges from 1 to 10, n
ranges from 0 to 20, and m is 0 to 4 and p is 0 or 1, preferably y
ranges from 1 to 3, x ranges from 0 to 3, z ranges from 1 to 4 and
n ranges from 0 to 5, and p is 0.
[0154] Preferred phenolic antioxidant compounds are the hindered
phenolics and phenolic esters which contain a sterically hindered
hydroxyl group, and these include those derivatives of dihydroxy
aryl compounds in which the hydroxyl groups are in the o- or
p-position to each other. Typical phenolic anti-oxidants include
the hindered phenols substituted with C.sub.1+ alkyl groups and the
alkylene coupled derivatives of these hindered phenols. Examples of
phenolic materials of this type 2-t-butyl-4-heptyl phenol;
2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecyl phenol;
2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;
2-methyl-6-t-butyl-4-heptyl phenol; 2-methyl-6-t-butyl-4-dodecyl
phenol; 2,6-di-t-butyl-4 methyl phenol; 2,6-di-t-butyl-4-ethyl
phenol; and 2,6-di-t-butyl 4 alkoxy phenol; and
##STR00004##
[0155] Phenolic type antioxidants are well known in the lubricating
industry and commercial examples such as Ethanox.RTM. 4710,
Irganox.RTM. 1076, Irganox.RTM. L1035, Irganox.RTM. 1010,
Irganox.RTM. L109, Irganox.RTM. L118, Irganox.RTM. L135 and the
like are familiar to those skilled in the art. The above is
presented only by way of exemplification, not limitation on the
type of phenolic anti-oxidants which can be used.
[0156] The phenolic antioxidant can be employed in an amount in the
range of 0.1 to 3 wt %, preferably 0.25 to 2.5 wt %, more
preferably 0.5 to 2 wt % on an active ingredient basis.
[0157] Aromatic amine antioxidants include phenyl-.alpha.-naphthyl
amine which is described by the following molecular structure:
##STR00005##
wherein R.sup.z is hydrogen or a C.sub.1 to C.sub.14 linear or
C.sub.3 to C.sub.14 branched alkyl group, preferably C.sub.1 to
C.sub.10 linear or C.sub.3 to C.sub.10 branched alkyl group, more
preferably linear or branched C.sub.6 to C.sub.8 and n is an
integer ranging from 1 to 5 preferably 1. A particular example is
Irganox L06.
[0158] Other aromatic amine antioxidants include other alkylated
and non-alkylated aromatic amines such as aromatic monoamines of
the formula R.sup.8R.sup.9R.sup.10N where R.sup.8 is an aliphatic,
aromatic or substituted aromatic group, R.sup.9 is an aromatic or a
substituted aromatic group, and R.sup.10 is H, alkyl, aryl or
R.sup.11S(O).sub.XR.sup.12 where R.sup.11 is an alkylene,
alkenylene, or aralkylene group, R.sup.12 is a higher alkyl group,
or an alkenyl, aryl, or alkaryl group, and x is 0, 1 or 2. The
aliphatic group R.sup.8 may contain from 1 to 20 carbon atoms, and
preferably contains from 6 to 12 carbon atoms. The aliphatic group
is a saturated aliphatic group. Preferably, both R.sup.8 and
R.sup.9 are aromatic or substituted aromatic groups, and the
aromatic group may be a fused ring aromatic group such as naphthyl.
Aromatic groups R.sup.8 and R.sup.9 may be joined together with
other groups such as S.
[0159] Typical aromatic amines anti-oxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 14 carbon atoms. The
general types of such other additional amine antioxidants which may
be present include diphenylamines, phenothiazines, imidodibenzyls
and diphenyl phenylene diamines. Mixtures of two or more of such
other additional aromatic amines may also be present. Polymeric
amine antioxidants can also be used.
[0160] Another class of antioxidant used in lubricating oil
compositions and which may also be present are oil-soluble copper
compounds. Any oil-soluble suitable copper compound may be blended
into the lubricating oil. Examples of suitable copper antioxidants
include copper dihydrocarbyl thio- or dithio-phosphates and copper
salts of carboxylic acid (naturally occurring or synthetic). Other
suitable copper salts include copper dithiacarbamates, sulphonates,
phenates, and acetylacetonates. Basic, neutral, or acidic copper
Cu(I) and or Cu(II) salts derived from alkenyl succinic acids or
anhydrides are known to be particularly useful.
[0161] Such antioxidants may be used individually or as mixtures of
one or more types of antioxidants, the total amount employed being
an amount of 0.50 to 5 wt %, preferably 0.75 to 3 wt % (on an
as-received basis).
Detergents
[0162] In addition to the alkali or alkaline earth metal salicylate
detergent which is an optional component in the present disclosure,
other detergents may also be present. While such other detergents
can be present, it is preferred that the amount employed be such as
to not interfere with the synergistic effect attributable to the
presence of the salicylate. Therefore, most preferably such other
detergents are not employed.
[0163] If such additional detergents are present, they can include
alkali and alkaline earth metal phenates, sulfonates, carboxylates,
phosphonates and mixtures thereof. These supplemental detergents
can have total base number (TBN) ranging from neutral to highly
overbased, i.e. TBN of 0 to over 500, preferably 2 to 400, more
preferably 5 to 300, and they can be present either individually or
in combination with each other in an amount in the range of from 0
to 10 wt %, preferably 0.5 to 5 wt % (active ingredient) based on
the total weight of the formulated lubricating oil. As previously
stated, however, it is preferred that such other detergent not be
present in the formulation.
[0164] Such additional other detergents include by way of example
and not limitation calcium phenates, calcium sulfonates, magnesium
phenates, magnesium sulfonates and other related components
(including borated detergents).
Dispersants
[0165] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
may be ashless or ash-forming in nature. Preferably, the dispersant
is ashless. So called ashless dispersants are organic materials
that form substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0166] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorus. Typical hydrocarbon chains contain
50 to 400 carbon atoms.
[0167] A particularly useful class of dispersants are the
alkenylsuccinic derivatives, typically produced by the reaction of
a long chain substituted alkenyl succinic compound, usually a
substituted succinic anhydride, with a polyhydroxy or polyamino
compound. The long chain group constituting the oleophilic portion
of the molecule which confers solubility in the oil, is normally a
polyisobutylene group. Many examples of this type of dispersant are
well known commercially and in the literature. Exemplary U.S.
patents describing such dispersants are U.S. Pat. Nos. 3,172,892;
3,215,707; 3,219,666; 3,316,177; 3,341,542; 3,444,170; 3,454,607;
3,541,012; 3,630,904; 3,632,511; 3,787,374 and 4,234,435. Other
types of dispersant are described in U.S. Pat. Nos. 3,036,003;
3,200,107; 3,254,025; 3,275,554; 3,438,757; 3,454,555; 3,565,804;
3,413,347; 3,697,574; 3,725,277; 3,725,480; 3,726,882; 4,454,059;
3,329,658; 3,449,250; 3,519,565; 3,666,730; 3,687,849; 3,702,300;
4,100,082; 5,705,458. A further description of dispersants may be
found, for example, in European Patent Application No. 471 071, to
which reference is made for this purpose.
[0168] Hydrocarbyl-substituted succinic acid compounds are popular
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0169] Succinimides are formed by the condensation reaction between
alkenyl succinic anhydrides and amines. Molar ratios can vary
depending on the amine or polyamine. For example, the molar ratio
of alkenyl succinic anhydride to TEPA can vary from 1:1 to 5:1.
[0170] Succinate esters are formed by the condensation reaction
between alkenyl succinic anhydrides and alcohols or polyols. Molar
ratios can vary depending on the alcohol or polyol used. For
example, the condensation product of an alkenyl succinic anhydride
and pentaerythritol is a useful dispersant.
[0171] Succinate ester amides are formed by condensation reaction
between alkenyl succinic anhydrides and alkanol amines. For
example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine.
[0172] The molecular weight of the alkenyl succinic anhydrides will
typically range between 800 and 2,500. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid, and boron
compounds such as borate esters or highly borated dispersants. The
dispersants can be borated with from 0.1 to 5 moles of boron per
mole of dispersant reaction product.
[0173] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. Process aids and catalysts,
such as oleic acid and sulfonic acids, can also be part of the
reaction mixture. Molecular weights of the alkylphenols range from
800 to 2,500 or more.
[0174] Typical high molecular weight aliphatic acid modified
Mannich condensation products can be prepared from high molecular
weight alkyl-substituted hydroxyaromatics or HN(R).sub.2
group-containing reactants.
[0175] Examples of high molecular weight alkyl-substituted
hydroxyaromatic compounds are polypropylphenol, polybutylphenol,
and other polyalkylphenols. These polyalkylphenols can be obtained
by the alkylation, in the presence of an alkylating catalyst, such
as BF.sub.3, of phenol with high molecular weight polypropylene,
polybutylene, and other polyalkylene compounds to give alkyl
substituents on the benzene ring of phenol having an average
600-100,000 molecular weight.
[0176] Examples of HN(R).sub.2 group-containing reactants are
alkylene polyamines, principally polyethylene polyamines. Other
representative organic compounds containing at least one
HN(R).sub.2 group suitable for use in the preparation of Mannich
condensation products are well known and include the mono- and
di-amino alkanes and their substituted analogs, e.g., ethylamine
and diethanol amine; aromatic diamines, e.g., phenylene diamine,
diamino naphthalenes; heterocyclic amines, e.g., morpholine,
pyrrole, pyrrolidine, imidazole, imidazolidine, and piperidine;
melamine and their substituted analogs.
[0177] Examples of alkylene polyamine reactants include
ethylenediamine, diethylene triamine, triethylene tetraamine,
tetraethylene pentaamine, pentaethylene hexamine, hexaethylene
heptaamine, heptaethylene octaamine, octaethylene nonaamine,
nonaethylene decamine, and decaethylene undecamine and mixture of
such amines having nitrogen contents corresponding to the alkylene
polyamines, in the formula H.sub.2N--(Z--NH--)H, mentioned before,
Z is a divalent ethylene and n is 1 to 10 of the foregoing formula.
Corresponding propylene polyamines such as propylene diamine and
di-, tri-, tetra-, pentapropylene tri-, tetra-, penta- and
hexaamines are also suitable reactants. The alkylene polyamines are
usually obtained by the reaction of ammonia and dihalo alkanes,
such as dichloro alkanes. Thus the alkylene polyamines obtained
from the reaction of 2 to 11 moles of ammonia with 1 to 10 moles of
dichloroalkanes having 2 to 6 carbon atoms and the chlorines on
different carbons are suitable alkylene polyamine reactants.
[0178] Aldehyde reactants useful in the preparation of the high
molecular products useful in this disclosure include the aliphatic
aldehydes such as formaldehyde (also as paraformaldehyde and
formalin), acetaldehyde and aldol (.beta.-hydroxybutyraldehyde).
Formaldehyde or a formaldehyde-yielding reactant is preferred.
[0179] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
500 to 5000 or more or a mixture of such hydrocarbylene groups.
Other preferred dispersants include succinic acid-esters and
amides, alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components. Such additives may be
used in an amount of 0.1 to 20 wt %, preferably 0.1 to 8 wt %, more
preferably 1 to 6 wt % (on an as-received basis) based on the
weight of the total lubricant.
Pour Point Depressants
[0180] Conventional pour point depressants (also known as lube oil
flow improvers) may also be present. Pour point depressant may be
added to lower the minimum temperature at which the fluid will flow
or can be poured. Examples of suitable pour point depressants
include alkylated naphthalenes polymethacrylates, polyacrylates,
polyarylamides, condensation products of haloparaffin waxes and
aromatic compounds, vinyl carboxylate polymers, and terpolymers of
dialkylfumarates, vinyl esters of fatty acids and allyl vinyl
ethers. Such additives may be used in amount of 0.0 to 0.5 wt %,
preferably 0 to 0.3 wt %, more preferably 0.001 to 0.1 wt % on an
as-received basis.
Corrosion Inhibitors/Metal Deactivators
[0181] Corrosion inhibitors are used to reduce the degradation of
metallic parts that are in contact with the lubricating oil
composition. Suitable corrosion inhibitors include aryl thiazines,
alkyl substituted dimercapto thiodiazoles thiadiazoles and mixtures
thereof. Such additives may be used in an amount of 0.01 to 5 wt %,
preferably 0.01 to 1.5 wt %, more preferably 0.01 to 0.2 wt %,
still more preferably 0.01 to 0.1 wt % (on an as-received basis)
based on the total weight of the lubricating oil composition.
Seal Compatibility Additives
[0182] Seal compatibility agents help to swell elastomeric seals by
causing a chemical reaction in the fluid or physical change in the
elastomer. Suitable seal compatibility agents for lubricating oils
include organic phosphates, aromatic esters, aromatic hydrocarbons,
esters (butylbenzyl phthalate, for example), and polybutenyl
succinic anhydride and sulfolane-type seal swell agents such as
Lubrizol 730-type seal swell additives. Such additives may be used
in an amount of 0.01 to 3 wt %, preferably 0.01 to 2 wt % on an
as-received basis.
Anti-Foam Agents
[0183] Anti-foam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical anti-foam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Anti-foam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 percent,
preferably 0.001 to 0.5 wt %, more preferably 0.001 to 0.2 wt %,
still more preferably 0.0001 to 0.15 wt % (on an as-received basis)
based on the total weight of the lubricating oil composition.
Inhibitors and Antirust Additives
[0184] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. One type of antirust additive is a
polar compound that wets the metal surface preferentially,
protecting it with a film of oil. Another type of antirust additive
absorbs water by incorporating it in a water-in-oil emulsion so
that only the oil touches the surface. Yet another type of antirust
additive chemically adheres to the metal to produce a non-reactive
surface. Examples of suitable additives include zinc
dithiophosphates, metal phenolates, basic metal sulfonates, fatty
acids and amines. Such additives may be used in an amount of 0.01
to 5 wt %, preferably 0.01 to 1.5 wt % on an as-received basis.
[0185] The term "organo molybdenum-nitrogen complexes" embraces the
organo molybdenum-nitrogen complexes described in U.S. Pat. No.
4,889,647. The complexes are reaction products of a fatty oil,
dithanolamine and a molybdenum source. Specific chemical structures
have not been assigned to the complexes. U.S. Pat. No. 4,889,647
reports an infrared spectrum for a typical reaction product of that
disclosure; the spectrum identifies an ester carbonyl band at 1740
cm.sup.-1 and an amide carbonyl band at 1620 cm.sup.-1. The fatty
oils are glyceryl esters of higher fatty acids containing at least
12 carbon atoms up to 22 carbon atoms or more. The molybdenum
source is an oxygen-containing compound such as ammonium
molybdates, molybdenum oxides and mixtures.
[0186] Other organo molybdenum complexes which can be used in the
present disclosure are tri-nuclear molybdenum-sulfur compounds
described in EP 1 040 115 and WO 99/31113 and the molybdenum
complexes described in U.S. Pat. No. 4,978,464.
Viscosity Modifiers
[0187] In addition to the copolymers described herein as part of
the disclosure the lubricating composition may optionally further
contain other known viscosity modifiers. The viscosity modifiers
may be hydrogenated styrene-butadiene rubbers, ethylene-propylene
copolymers, hydrogenated styrene-isoprene polymers, hydrogenated
diene polymers, polyalkyl styrenes, polyolefins, esters of maleic
anhydride-styrene copolymers, or mixtures thereof.
Antiwear Agents
[0188] The lubricating compositions can include at least one
antiwear agent. Examples of suitable antiwear agents include oil
soluble amine salts of phosphorus compounds, sulphurised olefins,
metal dihydrocarbyldithio-phosphates (such as zinc
dialkyldithiophosphates), thiocarbamate-containing compounds, such
as thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers,
alkylene-coupled thiocarbamates, and bis(S-alkyldithiocarbamyl)
disulphides.
[0189] 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.
[0190] 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 sulphur atom in the molecule. In one embodiment the
amine salt of the phosphorus compound may be ashless, i.e.,
metal-free (prior to being mixed with other components).
[0191] 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.
[0192] 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
oleyamine. 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.
[0193] 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.
[0194] 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,
tertdodecylamine, tert-tetradecylamine, tert-hexadecylamine,
tert-octadecylamine, tert-tetracosanylamine, and
tert-octacosanylamine.
[0195] 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.
[0196] Mixtures of amines may also be used in the disclosure. 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.11 to
C.sub.14 tertiary alkyl primary amines and C.sub.18 to C.sub.22
tertiary alkyl primary amines, respectively.
[0197] In one embodiment oil soluble amine salts of phosphorus
compounds include a sulphur-free amine salt of a
phosphorus-containing compound may be 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 International Application PCT/US08/051,126.
[0198] 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 Primene 81R.TM. (produced
and sold by Rohm & Haas) which is a mixture of C.sub.11 to
C.sub.14 tertiary alkyl primary amines.
[0199] 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.
[0200] 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 may be 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 reacting 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
(64 grams) at 58.degree. C. over a period of 45 minutes to 514
grams of hydroxypropyl 0,0-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
may be 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 sulphur, and
an acid number of 87 (bromophenol blue).
[0201] The dithiocarbamate-containing compounds may be prepared by
reacting a dithiocarbamate acid or salt with an unsaturated
compound. The dithiocarbamate containing compounds may also be
prepared by simultaneously reacting an amine, carbon disulphide and
an unsaturated compound. Generally, the reaction occurs at a
temperature from 25.degree. C. to 125.degree. C.
[0202] Examples of suitable olefins that may be sulphurised to form
an the sulphurised olefin include propylene, butylene, isobutylene,
pentene, hexane, heptene, octane, nonene, decene, undecene,
dodecene, undecyl, tridecene, tetradecene, pentadecene, hexadecene,
heptadecene, octadecene, octadecenene, nonodecene, eicosene or
mixtures thereof. In one embodiment, hexadecene, heptadecene,
octadecene, octadecenene, nonodecene, eicosene or mixtures thereof
and their dimers, trimers and tetramers are especially useful
olefins. Alternatively, the olefin may be a Diels-Alder adduct of a
diene such as 1,3-butadiene and an unsaturated ester, such as,
butylacrylate.
[0203] Another class of sulphurised olefin includes fatty acids and
their esters. The fatty acids are often obtained from vegetable oil
or animal oil; and typically contain 4 to 22 carbon atoms. Examples
of suitable fatty acids and their esters include triglycerides,
oleic acid, linoleic acid, palmitoleic acid or mixtures thereof.
Often, the fatty acids are obtained from lard oil, tall oil, peanut
oil, soybean oil, cottonseed oil, sunflower seed oil or mixtures
thereof. In one embodiment fatty acids and/or ester are mixed with
olefins.
[0204] 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 said
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.
[0205] Polyols include diols, triols, and alcohols with higher
numbers of alcoholic OH groups. Polyhydric alcohols include
ethylene glycols, including di-, tri- and tetraethylene glycols;
propylene glycols, including di-, tri- and tetrapropylene glycols;
glycerol; butane diol; hexane diol; sorbitol; arabitol; mannitol;
sucrose; fructose; glucose; cyclohexane diol; erythritol; and
pentaerythritols, including di- and tripentaerythritol. Often the
polyol is diethylene glycol, triethylene glycol, glycerol,
sorbitol, penta erythritol or dipentaerythritol.
[0206] The commercially available monoester known as "glycerol
monooleate" is believed to include 60+5 percent by weight of the
chemical species glycerol monooleate, along with 35+5 percent
glycerol dioleate, and less than 5 percent trioleate and oleic
acid. The amounts of the monoesters, described above, are
calculated based on the actual, corrected, amount of polyol
monoester present in any such mixture.
Extreme Pressure Agents
[0207] Extreme Pressure (EP) agents that are soluble in the oil
include sulphur- and chlorosulphur-containing EP agents,
chlorinated hydrocarbon EP agents and phosphorus EP agents.
Examples of such EP agents include chlorinated wax; sulphurised
olefins (such as sulphurised isobutylene), organic sulphides and
polysulphides such as dibenzyldisulphide, bis-(chlorobenzyl)
disulphide, dibutyl tetrasulphide, sulphurised methyl ester of
oleic acid, sulphurised alkylphenol, sulphurised dipentene,
sulphurised terpene, and sulphurised Diels-Alder adducts;
phosphosulphurised hydrocarbons such as the reaction product of
phosphorus sulphide with turpentine or methyl oleate; phosphorus
esters such as the dihydrocarbon and trihydrocarbon phosphites,
e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexyl
phosphite, pentylphenyl phosphite; dipentylphenyl phosphite,
tridecyl phosphite, distearyl phosphite and polypropylene
substituted phenol phosphite; metal thiocarbamates such as zinc
dioctyldithio carbamate and barium heptylphenol diacid; amine salts
of alkyl and dialkylphosphoric acids or derivatives; and mixtures
thereof (as described in U.S. Pat. No. 3,197,405).
[0208] The method and lubricating compositions of this disclosure
may be suitable for 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.
[0209] In one embodiment the method and lubricating composition of
the disclosure may be suitable for at least one of gear oils, axle
oils, drive shaft oils, traction oils, manual transmission oils or
automatic transmission oils. In one embodiment the disclosure
provides a method of lubricating a manual transmission.
[0210] An automatic transmission includes continuously variable
transmissions (CVT), infinitely variable transmissions (IVT),
toroidal transmissions, continuously slipping torque converter
clutches (CSTCC), stepped automatic transmissions or dual clutch
transmissions (DCT).
[0211] The internal combustion engines may be 2-stroke or 4-stroke
engines. Suitable internal combustion engines include marine diesel
engines, aviation piston engines, low-load diesel engines, and
automobile and truck engines.
[0212] As used herein, the term "(meth) acrylic" and related terms
includes both acrylic and methacrylic groups.
[0213] 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.).
[0214] As used herein the number of carbon atoms present in the
ester groups of the polymers of the disclosure is counted to
include only those carbon atoms of the alcohol-derived portion of
the ester group. Specifically, the number of carbon atoms excludes
the carbonyl carbon of the ester.
[0215] 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: hydrocarbon substituents,
including aliphatic, alicyclic, and aromatic substituents;
substituted hydrocarbon substituents, that is, substituents
containing non-hydrocarbon groups which, in the context of this
disclosure, do not alter the predominantly hydrocarbon nature of
the substituent; and hetero substituents, that is, substituents
which similarly have a predominantly hydrocarbon character but
contain other than carbon in a ring or chain.
[0216] In the above detailed description, the specific embodiments
of this disclosure have been described in connection with its
preferred embodiments. However, to the extent that the above
description is specific to a particular embodiment or a particular
use of this disclosure, this is intended to be illustrative only
and merely provides a concise description of the exemplary
embodiments. Accordingly, the disclosure is not limited to the
specific embodiments described above, but rather, the disclosure
includes all alternatives, modifications, and equivalents falling
within the true scope of the appended claims. Various modifications
and variations of this disclosure will be obvious to a worker
skilled in the art and it is to be understood that such
modifications and variations are to be included within the purview
of this application and the spirit and scope of the claims.
[0217] The following examples are for purposes of illustration only
and are non-limiting examples.
EXAMPLES
[0218] Lubricant compositions (i.e., axle oil blends) were prepared
by blending a polyalphaolefin base stock (e.g., mPAO 700, mPAO 450,
mPAO 300, mPAO 150, mPAO 65, mPAO 14, PAO 70, PAO 4, and PAO 6), a
hybrid olefin ester polymer (HOEP) viscosity modifier
(Meridian.TM.), and an axle oil additive package. The Meridian.TM.
viscosity modifier is available from Lubrizol Corporation. The axle
oil additive package used in Examples 1 and 2 is available from
Lubrizol Corporation as Anglamol.TM. 6043M. The axle oil additive
package used in Examples 3 and 4 is available from Afton
Chemicals.
Example 1
[0219] Wear control and load carrying capacity were determined for
lubricant compositions prepared as described hereinabove. The
results in FIG. 1 show 4-Ball Wear Scar (ASTM D4172) is reduced
when using the Meridian.TM. viscosity modifier alone or in
combination with mPAO 150 or mPAO 65. A surprising aspect of this
disclosure is that base oil and viscosity modifiers are not
expected to have significant impact on wear or load-carrying
properties of the fluid. FIG. 10 shows the results of 4-Ball Wear
Scar (ASTM D4172) for the designated lubricant compositions (i.e.,
blends).
Example 2
[0220] Over a broad viscosity range, a synergy was observed where
mixtures of mPAO 65 and Meridian.TM. gave higher Load Wear Index
(LWI) than either high viscosity component alone (FIG. 2). The
average friction coefficient measurements for multiple blends over
a broad viscosity range (FIG. 3) show lower friction as the
relative concentration of high viscosity components increase.
Surprisingly, however, the combination of mPAO 65 and Meridian.TM.
showed higher friction than either component alone. This synergy
implies the possibility of adjusting friction in applications such
as transmissions, which require a specific balance of frictional
characteristics, i.e., higher friction in some cases. FIG. 4 shows
on average 25-30% lower traction coefficients for lubricating
compositions containing mPAO 150, mPAO 65, and/or Meridian.TM.
compared to a conventional viscosity modifier. Lower traction
indicates potential axle efficiency enhancement and therefore
improved fuel economy. FIG. 11 shows the results of 4-Ball EP (ASTM
D2783) load wear index for the designated lubricant compositions
(i.e., blends). FIG. 12 shows the results of High Frequency
Reciprocating Rig (HFRR) friction coefficient for the designated
lubricant compositions (i.e., blends).
Example 3
[0221] Similar to Example 1 using a lubricating composition
containing mPAO 150 and Meridian.TM. (except for a different axle
oil additive package), an unexpected synergy was observed as shown
in FIGS. 5 and 6. Keeping to total concentration of high viscosity
material constant at 25 wt %, less viscosity loss was observed for
combinations of mPAO and Meridian.TM. than for either component
alone. This synergy was obvious in terms of absolute viscosity loss
and percent loss and shown in FIG. 5. Results are illustrated
graphically in FIG. 6. Durability of oil film due to enhanced shear
stability results in consistent performance and protection of
hardware over an extended period time compared to less shear stable
fluids. For high dispersant treated systems such as the lubricating
composition of this Example 3, this disclosure provides a method
for improving shear stability of axle fluids.
Example 4
[0222] Similar to Examples 1 and 3 using a lubricating compositions
containing mPAO 150 and Meridian.TM. (except for different axle oil
additive packages), FIG. 7 indicates a potential
antiwear/antiscuffing advantage for a Meridian.TM. viscosity
modifier in the FZG scuffing test even in a lower SAE 75W-80
viscosity formulation containing all Meridian.TM. as the viscosity
modifier. A trend reflecting lower Total Gear weight loss with
increased concentration of Meridian.TM. was observed in the FZG
test. All formulations showed excellent performance by delivering
">Stage 12" passing results, a requirement for premium high
performance gear oils.
[0223] Additional performance testing of these lower viscosity axle
fluid formulations were conducted to assess the impact of the high
VI synthetic components in areas such as oxidation stability and
deposit control. FIG. 8 shows surprisingly excellent sludge and
varnish results for fluids evaluated in 100-hr L60-1 Thermal and
Oxidative Stability test, which is double the standard duration
(i.e., 50 hours) required for SAE J2360 high performance gear oil
specification. The results clearly demonstrate that incorporation
of the Meridian.TM. viscosity modifier in the lubricating
compositions of this disclosure provides improved stability and
cleanliness even for already high performing technology. This
further substantiates the potential to formulation even higher
performing lower viscosity finished products by incorporating new
synthetic base fluids and viscosity modifiers.
[0224] Referring to FIG. 9, additional durability testing in a high
speed shock test for axle/gear oils used to assess anti-scoring
performance of fluids showed that even at lower kinematic viscosity
@100.degree. C., these oils still retained passing performance
under severe operating conditions. In the L-42 test procedure,
which is part of the SAE J2360 gear oil specification, the ring and
pinion gears are evaluated for scoring after a series of high speed
accelerations and rapid decelerations at temperatures up to
280.degree. F. In order to pass, the candidate lubricant must show
less scoring than the established passing reference oil.
[0225] All patents and patent applications, test procedures (such
as ASTM methods, UL methods, and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this disclosure and for all
jurisdictions in which such incorporation is permitted.
[0226] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0227] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *
References