U.S. patent application number 16/693981 was filed with the patent office on 2020-06-25 for method for improving high temperature antifoaming performance of a lubricating oil.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Michael L. Blumenfeld, Joshua D. Catanach, Douglas E. Deckman, Benjamin D. Eirich, Dmitry Khuseynov.
Application Number | 20200199477 16/693981 |
Document ID | / |
Family ID | 68944408 |
Filed Date | 2020-06-25 |
United States Patent
Application |
20200199477 |
Kind Code |
A1 |
Blumenfeld; Michael L. ; et
al. |
June 25, 2020 |
METHOD FOR IMPROVING HIGH TEMPERATURE ANTIFOAMING PERFORMANCE OF A
LUBRICATING OIL
Abstract
This disclosure provides a method for improving high temperature
antifoaming performance of a lubricating oil in an engine or other
mechanical component lubricated with the lubricating oil by using
as the lubricating oil a formulated oil. The formulated oil has a
composition with a lubricating oil base stock as a major component,
and at least one silicone antifoaming agent, as a minor component.
The silicone antifoaming agent is delivered to the lubricating oil
by contacting the lubricating oil with a cured silicone (e.g., room
temperature vulcanized (RTV) silicone) at a temperature, and for a
period of time, sufficient to deliver silicone to the lubricating
oil. The delivered silicone is soluble in the lubricating oil. The
lubricating oils are useful as passenger vehicle engine oils (PVEO)
and commercial vehicle engine oils (CVEO).
Inventors: |
Blumenfeld; Michael L.;
(Annandale, NJ) ; Deckman; Douglas E.; (Easton,
PA) ; Eirich; Benjamin D.; (Frenchtown, NJ) ;
Catanach; Joshua D.; (Bridgewater, NJ) ; Khuseynov;
Dmitry; (Washington, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
68944408 |
Appl. No.: |
16/693981 |
Filed: |
November 25, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62781728 |
Dec 19, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2070/00 20130101;
C10M 2205/173 20130101; C10M 2229/041 20130101; C10N 2030/18
20130101; C10M 169/041 20130101; C10M 2203/003 20130101; C10M
2229/02 20130101; C10M 2229/04 20130101; C10N 2040/25 20130101;
C10M 155/02 20130101 |
International
Class: |
C10M 155/02 20060101
C10M155/02; C10M 169/04 20060101 C10M169/04 |
Claims
1. A method for delivering a silicone antifoaming agent to a
lubricating oil, said method comprising contacting the lubricating
oil with a cured silicone at a temperature, and for a period of
time, sufficient to deliver silicone to the lubricating oil;
wherein the delivered silicone is soluble in the lubricating
oil.
2. The method of claim 1 wherein, in an engine or other mechanical
component lubricated with the lubricating oil, high temperature
antifoaming performance is improved as compared to high temperature
antifoaming performance achieved using a lubricating oil containing
a silicone antifoaming agent delivered from uncured silicone, as
determined by ASTM D6082 or ASTM D892 Sequence II.
3. The method of claim 1 wherein the cured silicone comprises room
temperature vulcanized (RTV) silicone.
4. The method of claim 1 wherein the temperature is from 10.degree.
C. to 30.degree. C., and the period of time is from 1 hour to 240
hours.
5. The method of claim 1 wherein the room temperature vulcanized
(RTV) silicone comprises low molecular weight leachates.
6. The method of claim 5 wherein the low molecular weight leachates
exhibit a bimodal molecular weight distribution, as determined by
gel permeation chromatography (GPC).
7. The method of claim 1 wherein the lubricating oil comprises a
Group I, Group II, Group III, Group IV or Group V base oil.
8. The method of claim 1 wherein the at least one silicone
antifoaming agent is present in an amount greater than 5 parts per
million (ppm).
9. The method of claim 1 wherein the lubricating oil further
comprises one or more of an antiwear additive, viscosity modifier,
antioxidant, detergent, dispersant, pour point depressant, metal
deactivator, seal compatibility additive, inhibitor, and anti-rust
additive.
10. A method for improving high temperature antifoaming performance
of a lubricating oil in an engine or other mechanical component
lubricated with the lubricating oil by using as the lubricating oil
a formulated oil, said formulated oil having a composition
comprising a lubricating oil base stock as a major component; and
at least one silicone antifoaming agent, as a minor component;
wherein the silicone antifoaming agent is delivered to the
lubricating oil by contacting the lubricating oil with a cured
silicone at a temperature, and for a period of time, sufficient to
deliver silicone to the lubricating oil; wherein the delivered
silicone is soluble in the lubricating oil; and wherein high
temperature antifoaming performance is improved as compared to high
temperature antifoaming performance achieved using a lubricating
oil containing a silicone antifoaming agent delivered from uncured
silicone, as determined by ASTM D6082 or ASTM D892 Sequence II.
11. The method of claim 10 wherein the cured silicone comprises
room temperature vulcanized (RTV) silicone.
12. The method of claim 10 wherein the temperature is from
10.degree. C. to 30.degree. C., and the period of time is from 1
hour to 240 hours.
13. The method of claim 10 wherein the room temperature vulcanized
(RTV) silicone comprises low molecular weight leachates.
14. The method of claim 13 wherein the low molecular weight
leachates exhibit a bimodal molecular weight distribution, as
determined by gel permeation chromatography (GPC).
15. The method of claim 10 wherein the lubricating oil base stock
comprises a Group I, Group II, Group III, Group IV or Group V base
oil.
16. The method of claim 10 wherein the at least one silicone
antifoaming agent is present in an amount greater than 5 parts per
million (ppm).
17. The method of claim 10 wherein the lubricating oil base stock
is present in an amount of from 50 weight percent to 95 weight
percent, based on the total weight of the formulated oil.
18. The method of claim 10 wherein the formulated oil further
comprises one or more of an antiwear additive, viscosity modifier,
antioxidant, detergent, dispersant, pour point depressant, metal
deactivator, seal compatibility additive, inhibitor, and anti-rust
additive.
19. A process for preparing a lubricating oil having a silicone
antifoaming agent, said process comprising contacting the
lubricating oil with a cured silicone at a temperature, and for a
period of time, sufficient to deliver silicone in the lubricating
oil; wherein the delivered silicone is soluble in the lubricating
oil.
20. The process of claim 19 wherein the cured silicone comprises
room temperature vulcanized (RTV) silicone.
21. The process of claim 19 wherein the temperature is from
10.degree. C. to 30.degree. C., and the period of time is from 1
hour to 240 hours.
22. The process of claim 19 wherein the room temperature vulcanized
(RTV) silicone comprises low molecular weight leachates.
23. The process of claim 22 wherein the low molecular weight
leachates exhibit a bimodal molecular weight distribution, as
determined by gel permeation chromatography (GPC).
24. The process of claim 19 wherein, in an engine or other
mechanical component lubricated with the lubricating oil, high
temperature antifoaming performance is improved as compared to high
temperature antifoaming performance achieved using a lubricating
oil containing a silicone antifoaming agent delivered from uncured
silicone, as determined by ASTM D6082 or ASTM D892 Sequence II.
25. The process of claim 19 wherein the lubricating oil comprises a
Group I, Group II, Group III, Group IV or Group V base oil.
26. The process of claim 19 wherein the at least one silicone
antifoaming agent is present in an amount greater than 5 parts per
million (ppm).
27. The process of claim 19 wherein the lubricating oil further
comprises one or more of an antiwear additive, viscosity modifier,
antioxidant, detergent, dispersant, pour point depressant, metal
deactivator, seal compatibility additive, inhibitor, and anti-rust
additive.
28. A lubricating oil having a composition comprising a lubricating
oil base stock as a major component; and at least one silicone
antifoaming agent as a minor component; wherein the silicone
antifoaming agent is delivered to the lubricating oil by contacting
the lubricating oil with a cured silicone at a temperature, and for
a period of time, sufficient to deliver silicone to the lubricating
oil; and wherein the delivered silicone is soluble in the
lubricating oil.
29. The lubricating oil of claim 28 wherein, in an engine or other
mechanical component lubricated with the lubricating oil, high
temperature antifoaming performance is improved as compared to high
temperature antifoaming performance achieved using a lubricating
oil containing a silicone antifoaming agent delivered from uncured
silicone, as determined by ASTM D6082 or ASTM D892 Sequence II.
30. The lubricating oil of claim 28 wherein the cured silicone
comprises room temperature vulcanized (RTV) silicone.
31. The lubricating oil of claim 28 wherein the temperature is from
10.degree. C. to 30.degree. C., and the period of time is from 1
hour to 240 hours.
32. The lubricating oil of claim 28 wherein the room temperature
vulcanized (RTV) silicone comprises low molecular weight lea
33. The lubricating oil of claim 32 wherein the low molecular
weight leachates exhibit a bimodal molecular weight distribution,
as determined by gel permeation chromatography (GPC).
34. The lubricating oil of claim 28 wherein the lubricating oil
base stock comprises a Group I, Group II, Group III, Group IV or
Group V base oil.
35. The lubricating oil of claim 28 wherein the at least one
silicone antifoaming agent is present in an amount greater than 5
parts per million (ppm).
36. The lubricating oil of claim 28 wherein the lubricating oil
base stock is present in an amount of from 50 weight percent to 95
weight percent, based on the total weight of the formulated
oil.
37. The lubricating oil of claim 28 wherein the formulated oil
further comprises one or more of an antiwear additive, viscosity
modifier, antioxidant, detergent, dispersant, pour point
depressant, metal deactivator, seal compatibility additive,
inhibitor, and anti-rust additive.
38. The lubricating oil of claim 28 which is a passenger vehicle
engine oil (PVEO) or a commercial vehicle engine oil (CVEO).
39. A lubricating oil having a composition comprising a lubricating
oil base stock as a major component; and at least one silicone
antifoaming agent as a minor component; wherein said lubricating
oil is prepared by a process that comprises contacting the
lubricating oil with a cured silicone at a temperature, and for a
period of time, sufficient to deliver silicone in the lubricating
oil; wherein the delivered silicone is soluble in the lubricating
oil.
40. The lubricating oil of claim 39 wherein the cured silicone
comprises room temperature vulcanized (RTV) silicone.
41. The lubricating oil of claim 39 wherein the temperature is from
10.degree. C. to 30.degree. C., and the period of time is from 1
hour to 240 hours.
42. The lubricating oil of claim 39 wherein the room temperature
vulcanized (RTV) silicone comprises low molecular weight
leachates.
43. The lubricating oil of claim 42 wherein the low molecular
weight leachates exhibit a bimodal molecular weight distribution,
as
44. The lubricating oil of claim 39 wherein, in an engine or other
mechanical component lubricated with the lubricating oil, high
temperature antifoaming performance is improved as compared to high
temperature antifoaming performance achieved using a lubricating
oil containing a silicone antifoaming agent delivered from uncured
silicone, as determined by ASTM D6082 or ASTM D892 Sequence II.
45. The lubricating oil of claim 39 wherein the lubricating oil
base stock comprises a Group I, Group II, Group III, Group IV or
Group V base oil.
46. The lubricating oil of claim 39 wherein the at least one
silicone antifoaming agent is present in an amount greater than 5
parts per million (ppm).
47. The lubricating oil of claim 39 which further comprises one or
more of an antiwear additive, viscosity modifier, antioxidant,
detergent, dispersant, pour point depressant, metal deactivator,
seal compatibility additive, inhibitor, and anti-rust additive.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/781,728, filed on Dec. 18, 2018, the entire
contents of which is incorporated herein by reference.
FIELD
[0002] This disclosure relates to a method for improving high
temperature antifoaming performance of a lubricating oil in an
engine or other mechanical component lubricated with the
lubricating oil by contacting the lubricating oil with a cured
silicone (e.g., room temperature vulcanized (RTV) silicone) at room
temperature for a moderate duration. The lubricating oils of this
disclosure are useful in internal combustion engines.
BACKGROUND
[0003] Defoamants are added to lubricants to prevent foam
generation in service. Foam is a concern of lubricant end users due
to: interference with lubricant-level monitoring; concern over
entrained air interfering with lubricant film thickness; cosmetic
issues (foam is easily visible and can indicate contamination);
potential for spill-over (slippery spots); and the like. In
particular, foam is a significant concern in gear oils as it
prevents accurate measurement of the lubricant level.
[0004] The current state of the art is the use of methylated
silicones namely polydimethylsiloxanes (PDMSs). However, the PDMSs
have a low refractive index, high density, high Si content, and are
removed by common filter material (including cellulosic and glass
fiber media).
[0005] Lubricants often depend on small amounts of insoluble,
silicone-based defoamants to provide optimal foam performance in a
broad array of applications and environments. The insoluble
material forms a dispersed phase which prevents the formation of
stable foams.
[0006] Defoamants are typically the most difficult component to add
to a lubricant blend. Forming a stable emulsion is very challenging
and depends on addition rate and mixing energy. Improper blending
leads to drop out of the defoamant which causes foam performance
issues and cosmetic problems. It would be preferred to add
defoamants in manner that did not depend on addition rate.
[0007] For ease of manufacture, defoamant materials may be
dissolved in a carrier fluid to create a defoamant concentrate.
Defoamant concentrates are then used to promote emulsion formation
in-situ through the solvent displacement method during lubricant
blending. Although typical formulations contain 0.05-0.50 wt. % of
defoamant concentrate, the total insoluble defoamant is often less
than 100 ppm, making the defoamant one of the most potent and
complex performance additives within a lubricant formulation.
[0008] Despite advances in lubricant oil formulation technology,
there exists a need for a method of adding antifoam that is stable
and provides protection against foam at high temperatures.
SUMMARY
[0009] This disclosure relates in part to a method for delivering a
silicone antifoaming agent to a lubricating oil. The method
involves contacting the lubricating oil with a cured silicone
(e.g., room temperature vulcanized (RTV) silicone) at a
temperature, and for a period of time, sufficient to deliver
silicone to the lubricating oil. The delivered silicone is soluble
in the lubricating oil.
[0010] This disclosure also relates in part to a method for
improving high temperature antifoaming performance of a lubricating
oil in an engine or other mechanical component lubricated with the
lubricating oil by using as the lubricating oil a formulated oil.
The formulated oil has a composition comprising a lubricating oil
base stock as a major component, and at least one silicone
antifoaming agent, as a minor component. The silicone antifoaming
agent is delivered to the lubricating oil by contacting the
lubricating oil with a cured silicone at a temperature, and for a
period of time, sufficient to deliver silicone to the lubricating
oil. The delivered silicone is soluble in the lubricating oil. High
temperature antifoaming performance is improved as compared to high
temperature antifoaming performance achieved using a lubricating
oil containing a silicone antifoaming agent delivered from uncured
silicone, as determined by ASTM D6082 or ASTM D892 Sequence II.
[0011] This disclosure further relates in part to a process for
preparing a lubricating oil having a silicone antifoaming agent.
The process comprises contacting the lubricating oil with a cured
silicone at a temperature, and for a period of time, sufficient to
deliver silicone in the lubricating oil. The delivered silicone is
soluble in the lubricating oil.
[0012] This disclosure still further relates in part to a
lubricating oil having a composition comprising a lubricating oil
base stock as a major component, and at least one silicone
antifoaming agent as a minor component. The silicone antifoaming
agent is delivered to the lubricating oil by contacting the
lubricating oil with a cured silicone at a temperature, and for a
period of time, sufficient to deliver silicone to the lubricating
oil. The delivered silicone is soluble in the lubricating oil.
[0013] In an embodiment, in an engine or other mechanical component
lubricated with the lubricating oil, high temperature antifoaming
performance is improved as compared to high temperature antifoaming
performance achieved using a lubricating oil containing a silicone
antifoaming agent delivered from uncured silicone, as determined by
ASTM D6082 or ASTM D892 Sequence II.
[0014] This disclosure yet further relates in part to a lubricating
oil having a composition comprising a lubricating oil base stock as
a major component, and at least one silicone antifoaming agent as a
minor component. The lubricating oil is prepared by a process that
comprises contacting the lubricating oil with a cured silicone at a
temperature, and for a period of time, sufficient to deliver
silicone in the lubricating oil. The delivered silicone is soluble
in the lubricating oil.
[0015] It has been surprisingly found that, in accordance with this
disclosure, improvements in high temperature antifoaming
performance are obtained in an engine or other mechanical component
lubricated with a lubricating oil, by including at least one
silicone antifoaming agent delivered from cured silicone, in the
lubricating oil.
[0016] In particular, it has been surprisingly found that, in
accordance with this disclosure, in an engine or other mechanical
component lubricated with the lubricating oil, high temperature
antifoaming performance is improved as compared to high temperature
antifoaming performance achieved using a lubricating oil containing
a silicone antifoaming agent delivered from uncured silicone, as
determined by ASTM D6082 or ASTM D892 Sequence II.
[0017] Also, it has been surprisingly found that, in ASTM D892
testing with the lubricating oils of this disclosure containing the
silicone antifoaming agent, foaming characteristics are negatively
impacted with the low temperature Sequences (I and III), whereas
foaming characteristics are largely unchanged with the high
temperature Sequence II. This surprising result allows targeting of
high temperature foam performance in a manner that was not
previously available in applications, where low temperature foam
performance is not required. This insight can be used to
selectively improve the Sequence II foam performance in oils with
poor Sequence II performance by treating them with RTV
silicone.
[0018] Other objects and advantages of the present disclosure will
become apparent from the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 graphically shows that RTV silicone agent improves
foam performance (lower is better), as determined by ASTM D6082, in
accordance with the Examples.
[0020] FIG. 2 graphically shows ASTM D892 testing results in which
the low temperature Sequences (I and III) are impacted negatively,
and the Sequence II performance is largely unchanged. For the
treated oils that include fresh oil with different levels of
exposure to heat and RTV silicone, FIG. 2 graphically shows the
selectivity of the treatment towards Sequence II foam performance,
and Sequences I and III foam performance are impacted, in
accordance with the Examples.
[0021] FIG. 3 graphically shows ASTM D892 Sequence II testing
results for two pre-treatment poor performing lubricating oils that
were treated with RTV silicone. For the treated oils that include
fresh oil with different levels of exposure to heat and amounts
(ppm) of RTV silicone, FIG. 3 graphically shows improved foam
performance (lower is better), as determined by ASTM D892 Sequence
II, in accordance with the Examples.
[0022] FIG. 4 graphically shows ASTM D892 testing results for two
treated two treated lubricating oils with GTL 4 base stock and
differently sourced RTV silicone in which the low temperature
Sequences (I and III) are impacted negatively, and the Sequence II
performance is largely unchanged. These plots show impact on high
performing oils, and that the composition of the silicone (Dow or
AC Delco) can be used to fine tune the performance desired. In this
case, the Dow is superior for overall low foam protection, in
particular at 50 ppm of treatment. For the treated oils that
include fresh oil with GTL base stock and differently sourced RTV
silicone and with different levels of exposure to heat and amounts
(ppm) of RTV silicone, FIG. 4 shows improved foam performance
(lower is better), as determined by ASTM D892 Sequence II, in
accordance with the Examples.
[0023] FIG. 5 shows gel permeation chromatography (GPC) of extracts
or leachates from differently sourced RTV silicone. As shown in
FIG. 5, differently sourced RTV silicones have different extracts
or leachates having different molecular weight distributions. FIG.
5 shows a bimodal molecular weight distribution for the differently
sourced RTV silicones, in accordance with the Examples.
[0024] FIG. 6 graphically shows the impact of temperature and
contacting time on the amount of leachates as measured by silicone
content as determined by ASTM D5185, in accordance with the
Examples.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Definitions
[0025] "About" or "approximately." 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.
[0026] "Major amount" as it relates to components included within
the lubricating oils of the specification and the claims means
greater than or equal to 50 wt. %, or greater than or equal to 60
wt. %, or greater than or equal to 70 wt. %, or greater than or
equal to 80 wt. %, or greater than or equal to 90 wt. % based on
the total weight of the lubricating oil.
[0027] "Minor amount" as it relates to components included within
the lubricating oils of the specification and the claims means less
than 50 wt. %, or less than or equal to 40 wt. %, or less than or
equal to 30 wt. %, or greater than or equal to 20 wt. %, or less
than or equal to 10 wt. %, or less than or equal to 5 wt. %, or
less than or equal to 2 wt. %, or less than or equal to 1 wt. %,
based on the total weight of the lubricating oil.
[0028] "Essentially free" as it relates to components included
within the lubricating oils of the specification and the claims
means that the particular component is at 0 weight % within the
lubricating oil, or alternatively is at impurity type levels within
the lubricating oil (less than 100 ppm, or less than 20 ppm, or
less than 10 ppm, or less than 1 ppm).
[0029] "Other lubricating oil additives" as used in the
specification and the claims means other lubricating oil additives
that are not specifically recited in the particular section of the
specification or the claims. For example, other lubricating oil
additives may include, but are not limited to, antioxidants,
detergents, dispersants, antiwear additives, corrosion inhibitors,
viscosity modifiers, metal passivators, pour point depressants,
seal compatibility agents, antifoam agents, extreme pressure
agents, friction modifiers and combinations thereof.
[0030] "Other mechanical component" as used in the specification
and the claims means an electric vehicle component, a hybrid
vehicle component, a power train, a driveline, a transmission, a
gear, a gear train, a gear set, a compressor, a pump, a hydraulic
system, a bearing, a bushing, a turbine, a piston, a piston ring, a
cylinder liner, a cylinder, a cam, a tappet, a lifter, a gear, a
valve, or a bearing including a journal, a roller, a tapered, a
needle, and a ball bearing.
[0031] "Hydrocarbon" refers to a compound consisting of carbon
atoms and hydrogen atoms.
[0032] "Alkane" refers to a hydrocarbon that is completely
saturated. An alkane can be linear, branched, cyclic, or
substituted cyclic.
[0033] "Olefin" refers to a non-aromatic hydrocarbon comprising one
or more carbon-carbon double bond in the molecular structure
thereof.
[0034] "Mono-olefin" refers to an olefin comprising a single
carbon-carbon double bond.
[0035] "Cn" group or compound refers to a group or a compound
comprising carbon atoms at total number thereof of n. Thus, "Cm-Cn"
group or compound refers to a group or compound comprising carbon
atoms at a total number thereof in the range from m to n. Thus, a
C1-C50 alkyl group refers to an alkyl group comprising carbon atoms
at a total number thereof in the range from 1 to 50.
[0036] "Carbon backbone" refers to the longest straight carbon
chain in the molecule of the compound or the group in question.
"Branch" refer to any substituted or unsubstituted hydrocarbyl
group connected to the carbon backbone. A carbon atom on the carbon
backbone connected to a branch is called a "branched carbon."
[0037] "Epsilon-carbon" in a branched alkane refers to a carbon
atom in its carbon backbone that is (i) connected to two hydrogen
atoms and two carbon atoms and (ii) connected to a branched carbon
via at least four (4) methylene (CH.sub.2) groups. Quantity of
epsilon carbon atoms in terms of mole percentage thereof in a
alkane material based on the total moles of carbon atoms can be
determined by using, e.g., .sup.13C NMR.
[0038] "Alpha-carbon" in a branched alkane refers to a carbon atom
in its carbon backbone that is with a methyl end with no branch on
the first 4 carbons. It is also measured in mole percentage using
.sup.13C NMR.
[0039] "SAE" refers to SAE International, formerly known as Society
of Automotive Engineers, which is a professional organization that
sets standards for internal combustion engine lubricating oils.
[0040] "SAE J300" refers to the viscosity grade classification
system of engine lubricating oils established by SAE, which defines
the limits of the classifications in rheological terms only.
[0041] "Base stock" or "base oil" interchangeably refers to an oil
that can be used as a component of lubricating oils, heat transfer
oils, hydraulic oils, grease products, and the like.
[0042] "Lubricating oil" or "lubricant" interchangeably refers to a
substance that can be introduced between two or more surfaces to
reduce the level of friction between two adjacent surfaces moving
relative to each other. A lubricant base stock is a material,
typically a fluid at various levels of viscosity at the operating
temperature of the lubricant, used to formulate a lubricant by
admixing with other components. Non-limiting examples of base
stocks suitable in lubricants include API Group I, Group II, Group
III, Group IV, and Group V base stocks. PAOs, particularly
hydrogenated PAOs, have recently found wide use in lubricants as a
Group IV base stock, and are particularly preferred. If one base
stock is designated as a primary base stock in the lubricant,
additional base stocks may be called a co-base stock.
[0043] All kinematic viscosity values in this disclosure are as
determined pursuant to ASTM D445. Kinematic viscosity at
100.degree. C. is reported herein as KV100, and kinematic viscosity
at 40.degree. C. is reported herein as KV40. Unit of all KV100 and
KV40 values herein is cSt unless otherwise specified.
[0044] All viscosity index ("VI") values in this disclosure are as
determined pursuant to ASTM D2270.
[0045] All Noack volatility ("NV") values in this disclosure are as
determined pursuant to ASTM D5800 unless specified otherwise. Unit
of all NV values is wt %, unless otherwise specified.
[0046] All pour point values in this disclosure are as determined
pursuant to ASTM D5950 or D97.
[0047] All CCS viscosity ("CCSV") values in this disclosure are as
determined pursuant to ASTM 5293. Unit of all CCSV values herein is
millipascal second (mPa$), which is equivalent to centipoise),
unless specified otherwise. All CCSV values are measured at a
temperature of interest to the lubricating oil formulation or oil
composition in question. Thus, for the purpose of designing and
fabricating engine oil formulations, the temperature of interest is
the temperature at which the SAE J300 imposes a minimal CCSV.
[0048] All percentages in describing chemical compositions herein
are by weight unless specified otherwise. "Wt. %" means percent by
weight.
Methods and Lubricating Oil Compositions of this Disclosure
[0049] It has now been found that moderate-duration room
temperature contact between a lubricant and a room temperature
vulcanized (RTV) silicone leads to an unexpected change in the
interfacial properties of the lubricant. The addition of soluble
silicone to a lubricant was previously anticipated to produce a
worsening of foam performance due to a lowering of the lubricant
surface tension. However, in this disclosure, the combination of
RTV silicone and the lubricant leads to a foam performance
improvement as measured by ASTM D892 Sequence II and ASTM
D6082.
[0050] Moreover, this disclosure is particularly unique in that
provides a benefit to high temperature foam performance and not
room temperature foam performance. There are many instances where
only D892 Sequence II is required as high temperature foam
performance is considered the most severe case and it is assumed
that a high performing D892 Sequence II result implies a good D892
Sequence I and Sequence III results. This disclosure allows for a
selective targeting of D892 Sequence II, and provides a level of
performance control that was previously unavailable to formulators
based on present state of the art. It has also been determined that
this is unique to RTV silicones with low molecular weight
leachates.
[0051] In an embodiment, the RTV silicone comprises low molecular
weight leachates. The low molecular weight leachates preferably
exhibit a bimodal molecular weight distribution, as determined by
gel permeation chromatography (GPC).
[0052] This disclosure provides various benefits including:
improvement to high temperature foam performance in engine oils as
measured by ASTM D6082; the ability to improve foam performance as
measured by ASTM D892 Sequence II; the potential to improve foam
performance in a manner that is thermodynamically stable (e.g.
soluble); a unique method of antifoam delivery that has
manufacturability advantages; and a tool for formulators to provide
specificity in performance (e.g. if a formulation needs good high
temperature foam performance but not low temperature foam
performance).
[0053] In accordance with this disclosure, the silicone antifoam
agents are delivered to a lubricating oil by contacting the
lubricating oil with a cured silicone at a temperature, and for a
period of time, sufficient to deliver the silicone antifoam agent
to the lubricating oil. The delivered silicone antifoam agent is
soluble in the lubricating oil. The temperature is from about
10.degree. C. to about 30.degree. C., preferably room temperature,
and the period of time is from about 1 hour to about 240 hours,
preferably from about 1 hour to about 72 hours, and more preferably
from about 1 hour to about 24 hours. A preferred cured silicone for
use in this disclosure is room temperature vulcanized (RTV)
silicone.
[0054] In an embodiment, RTV silicone immersed in lubricant at room
temperature delivers the high temperature antifoam agent. It has
been found that the silicone must be cured to deliver the agent.
Uncured silicone is ineffective. The cured silicone agent delivery
method is less susceptible to blending error, as the delivered
silicone agent is soluble and the rate of addition is fixed by
diffusion.
[0055] The lubricating oils of this disclosure provide excellent
high temperature antifoaming performance. This benefit has been
demonstrated for the lubricating oils of this disclosure in the
high temperature test method for foaming characteristics of
lubricating oils in accordance with ASTM D892 and ASTM D6082.
[0056] The lubricant compositions of this disclosure provide
advantaged antifoaming performance in lubricant compositions, which
can include, for example, lubricating liquids, dispersions,
suspensions, material concentrates, additive concentrates, and the
like.
[0057] The lubricant compositions of this disclosure provide
advantaged antifoaming performance under diverse lubrication
regimes, that include, for example, hydrodynamic,
elastohydrodynamic, boundary, mixed lubrication, extreme pressure
regimes, and the like.
[0058] One of the benefits of the current disclosure is that it
allows the lubricating oil to be additized outside of a blend
plant, for example, by including the RTV silicone in the
lubricating oil outside of the
[0059] The lubricating oils of this disclosure are particularly
advantageous as passenger vehicle engine oil (PVEO) products and
commercial vehicle engine oil (CVEO) products.
Lubricating Oil Base Stocks
[0060] A wide range of lubricating base oils is known in the art.
Lubricating base oils that are useful in the present disclosure are
natural oils, mineral oils and synthetic oils, and unconventional
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 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.
[0061] Groups I, II, III, IV and V are broad base oil stock
categories 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 have a viscosity index
of between about 80 to 120 and contain greater than about 0.03%
sulfur and/or less than about 90% saturates. Group II base stocks
have a viscosity index of between about 80 to 120, and contain less
than or equal to about 0.03% sulfur and greater than or equal to
about 90% saturates. Group III stocks have a viscosity index
greater than about 120 and contain less than or equal to about
0.03% sulfur and greater than about 90% saturates. Group IV
includes polyalphaolefins (PAO). Group V base stock includes base
stocks not included in Groups I-IV. The table below summarizes
properties of each of these five groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity 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
polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III or IV
[0062] 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. 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.
[0063] Group II and/or Group III hydroprocessed or hydrocracked
base stocks, including synthetic oils such as alkyl aromatics and
synthetic esters are also well known base stock oils.
[0064] Synthetic oils include hydrocarbon oil. Hydrocarbon oils
include oils 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 are 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.
[0065] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron
Phillips Chemical Company, BP, and others, typically vary from
about 250 to about 3,000, although PAO's may be made in viscosities
up to about 150 cSt (100.degree. C.). The PAOs are typically
comprised of relatively low molecular weight hydrogenated polymers
or oligomers of alphaolefins which include, but are not limited to,
C.sub.2 to about C.sub.32 alphaolefins with the C.sub.8 to about
C.sub.16 alphaolefins, such as 1-octene, 1-decene, 1-dodecene and
the like, being preferred. The preferred polyalphaolefins are
poly-1-octene, poly-1-decene and poly-1-dodecene and mixtures
thereof and mixed olefin-derived polyolefins. However, the dimers
of higher olefins in the range of C.sub.14 to C.sub.18 may be used
to provide low viscosity base stocks of acceptably low volatility.
Depending on the viscosity grade and the starting oligomer, the
PAOs may be predominantly trimers and tetramers of the starting
olefins, with minor amounts of the higher oligomers, having a
viscosity range of 1.5 to 12 cSt. PAO fluids of particular use may
include 3.0 cSt, 3.4 cSt, and/or 3.6 cSt and combinations thereof.
Mixtures of PAO fluids having a viscosity range of 1.5 to
approximately 150 cSt or more may be used if desired.
[0066] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. Nos. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C.sub.14 to C.sub.18
olefins are described in U.S. Pat. No. 4,218,330.
[0067] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof. Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (LHDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269, the disclosure of which is incorporated
herein by reference in its entirety. Processes for making
hydrocracked/hydroisomerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Each of the aforementioned patents is incorporated
herein in their entirety. Particularly favorable processes are
described in European Patent Application Nos. 464546 and 464547,
also incorporated herein by reference. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. Nos. 4,594,172
and 4,943,672, the disclosures of which are incorporated herein by
reference in their entirety.
[0068] Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived
base oils, and other wax-derived hydroisomerized (wax isomerate)
base oils be advantageously used in the instant disclosure, and may
have useful kinematic viscosities at 100.degree. C. of about 3 cSt
to about 50 cSt, preferably about 3 cSt to about 30 cSt, more
preferably about 3.5 cSt to about 25 cSt, as exemplified by GTL 4
with kinematic viscosity of about 4.0 cSt at 100.degree. C. and a
viscosity index of about 141. These Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and other wax-derived
hydroisomerized base oils may have useful pour points of about
-20.degree. C. or lower, and under some conditions may have
advantageous pour points of about -25.degree. C. or lower, with
useful pour points of about -30.degree. C. to about -40.degree. C.
or lower. Useful compositions of Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and wax-derived
hydroisomerized base oils are recited in U.S. Pat. Nos. 6,080,301;
6,090,989, and 6,165,949 for example, and are incorporated herein
in their entirety by reference.
[0069] The hydrocarbyl aromatics can be used as a base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least about 5% of its weight derived from an aromatic moiety such
as a benzenoid moiety or naphthenoid moiety, or their derivatives.
These hydrocarbyl aromatics include alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and the like. The aromatic can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can also be comprised
of mixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl
groups, cycloalkenyl groups and other related hydrocarbyl groups.
The hydrocarbyl groups can range from about C.sub.6 up to about
C.sub.60 with a range of about C.sub.8 to about C.sub.20 often
being preferred. A mixture of hydrocarbyl groups is often
preferred, and up to about three such substituents may be present.
The hydrocarbyl group can optionally contain sulfur, oxygen, and/or
nitrogen containing substituents. The aromatic group can also be
derived from natural (petroleum) sources, provided at least about
5% of the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to about 50
cSt are preferred, with viscosities of approximately 3.4 cSt to
about 20 cSt often being more preferred for the hydrocarbyl
aromatic component. In one embodiment, an alkyl naphthalene where
the alkyl group is primarily comprised of 1-hexadecene is used.
Other alkylates of aromatics can be advantageously used.
Naphthalene or methyl naphthalene, for example, can be alkylated
with olefins such as octene, decene, dodecene, tetradecene or
higher, mixtures of similar olefins, and the like. Useful
concentrations of hydrocarbyl aromatic in a lubricant oil
composition can be about 2% to about 25%, preferably about 4% to
about 20%, and more preferably about 4% to about 15%, depending on
the application.
[0070] Alkylated aromatics such as the hydrocarbyl aromatics of the
present disclosure may be produced by well-known Friedel-Crafts
alkylation of aromatic compounds. See Friedel-Crafts and Related
Reactions, Olah, G. A. (ed.), Inter-science Publishers, New York,
1963. For example, an aromatic compound, such as benzene or
naphthalene, is alkylated by an olefin, alkyl halide or alcohol in
the presence of a Friedel-Crafts catalyst. See Friedel-Crafts and
Related Reactions, Vol. 2, part 1, chapters 14, 17, and 18, See
Olah, G. A. (ed.), Inter-science Publishers, New York, 1964. Many
homogeneous or heterogeneous, solid catalysts are known to one
skilled in the art. The choice of catalyst depends on the
reactivity of the starting materials and product quality
requirements. For example, strong acids such as AlCl.sub.3,
BF.sub.3, or HF may be used. In some cases, milder catalysts such
as FeCl.sub.3 or SnCl.sub.4 are preferred. Newer alkylation
technology uses zeolites or solid super acids.
[0071] Esters comprise a useful base stock. 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, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic 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.
[0072] 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 about 4 carbon atoms, preferably C.sub.5 to
C.sub.30 acids such as saturated straight chain fatty acids
including caprylic acid, capric acid, 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.
[0073] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
monocarboxylic acids containing from about 5 to about 10 carbon
atoms. These esters are widely available commercially, for example,
the Mobil P-41 and P-51 esters of ExxonMobil Chemical Company.
[0074] Also useful are esters derived from renewable material such
as coconut, palm, rapeseed, soy, sunflower and the like. These
esters may be monoesters, di-esters, polyol esters, complex esters,
or mixtures thereof. These esters are widely available
commercially, for example, the Esterex NP 343 ester of ExxonMobil
Chemical Company.
[0075] Engine oil formulations containing renewable esters are
included in this disclosure. For such formulations, the renewable
content of the ester is typically greater than about 70 weight
percent, preferably more than about 80 weight percent and most
preferably more than about 90 weight percent.
[0076] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0077] Non-conventional or unconventional base stocks/base oils
include one or more of a mixture of base stock(s) derived from one
or more Gas-to-Liquids (GTL) materials, as well as
isomerate/isodewaxate base stock(s) derived from natural wax or
waxy feeds, mineral and or non-mineral oil waxy feed stocks such as
slack waxes, natural waxes, and waxy stocks such as gas oils, waxy
fuels hydrocracker bottoms, waxy raffinate, hydrocrackate, thermal
crackates, or other mineral, mineral oil, or even non-petroleum oil
derived waxy materials such as waxy materials received from coal
liquefaction or shale oil, and mixtures of such base stocks.
[0078] 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.
[0079] 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 about 2 mm.sup.2/s to about 50 mm.sup.2/s
(ASTM D445). They are further characterized typically as having
pour points of -5.degree. C. to about -40.degree. C. or lower (ASTM
D97). They are also characterized typically as having viscosity
indices of about 80 to about 140 or greater (ASTM D2270).
[0080] 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 about 10 ppm, and
more typically less than about 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 phosphorus and aromatics make this
materially especially suitable for the formulation of low SAP
products.
[0081] 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.
[0082] 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).
[0083] 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 I, Group II, Group III, Group IV, and
Group V oils and mixtures thereof, preferably API Group II, Group
III, Group IV, and Group V oils and mixtures thereof, more
preferably the Group III to Group V 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.
[0084] The base oil constitutes the major component of the engine
oil lubricant composition of the present disclosure and typically
is present in an amount ranging from about 50 to about 99 weight
percent, preferably from about 70 to about 95 weight percent, and
more preferably from about 85 to about 95 weight percent, based on
the total weight of the composition. The base oil may be selected
from any of the synthetic or natural oils typically used as
crankcase lubricating oils for spark-ignited and
compression-ignited engines. The base oil conveniently has a
kinematic viscosity, according to ASTM standards, of about 2.5 cSt
to about 12 cSt (or mm.sup.2/s) at 100.degree. C. and preferably of
about 2.5 cSt to about 9 cSt (or mm.sup.2/s) at 100.degree. C.
Mixtures of synthetic and natural base oils may be used if desired.
Bi-modal mixtures of Group I, II, III, IV, and/or V base stocks may
be used if desired.
Silicone Antifoam Agents
[0085] The silicone antifoam agents of this disclosure are
delivered to a lubricating oil by contacting the lubricating oil
with a cured silicone at a temperature, and for a period of time,
sufficient to deliver the silicone antifoam agent to the
lubricating oil. The delivered silicone antifoam agent is soluble
in the lubricating oil. The temperature is from about 10.degree. C.
to about 30.degree. C., preferably from about 12.degree. C. to
about 28.degree. C., and more preferably from about 14.degree. C.
to about 26.degree. C. The period of time is from about 1 hour to
about 240 hours, preferably from about 1 hour to about 72 hours,
and more preferably from about 1 hour to about 24 hours.
[0086] A preferred cured silicone for use in this disclosure is
room temperature vulcanized (RTV) silicone.
[0087] In an embodiment, the silicone antifoam agents of this
disclosure can be used alone or in addition to conventiona
[0088] In an embodiment, RTV silicone immersed in lubricant at room
temperature delivers the high temperature antifoam agent. It has
been found that the silicone must be cured to deliver the agent.
Uncured silicone is ineffective. The cured silicone agent delivery
method is less susceptible to blending error, as the delivered
silicone agent is soluble and the rate of addition is fixed by
diffusion.
[0089] In an embodiment, the RTV silicone comprises low molecular
weight leachates. The low molecular weight leachates preferably
exhibit a bimodal molecular weight distribution, as determined by
gel permeation chromatography (GPC).
[0090] Illustrative low molecular leachates include, for example,
cyclic or linear polysiloxanes such as polydimethylsiloxanes and
other organo-modified polydimethyl siloxanes.
[0091] In an embodiment, in an engine or other mechanical component
lubricated with the lubricating oil, high temperature antifoaming
performance is improved as compared to high temperature antifoaming
performance achieved using a lubricating oil containing a silicone
antifoaming agent delivered from uncured silicone, as determined by
ASTM D6082 or ASTM D892 Sequence II.
[0092] The at least one silicone antifoaming agent is present in an
amount greater than about 5 parts per million (ppm), or greater
than about 10 parts per million (ppm), or greater than about 15
parts per million (ppm), or greater than about 20 parts per million
(ppm), or greater than about 25 parts per million (ppm), or greater
than about 30 parts per million (ppm), or greater than about 35
parts per million (ppm), or greater than about 40 parts per million
(ppm), or greater than about 45 parts per million (ppm), or greater
than about 50 parts per million (ppm), or greater than about 60
parts per million (ppm), or greater than about 70 parts per million
(ppm), or greater than about 80 parts per million (ppm), or greater
than about 90 parts per million (ppm), or greater than about 100
parts per million (ppm).
[0093] The silicone antifoam agents are advantageously delivered
from cured silicone to the lubricating oils of this disclosure.
These agents retard the formation of stable foams. The cured
silicone is commercially available and may be used in conventional
amounts, for example, usually an amount sufficient to provide a
concentration of silicone antifoam agent in the lubricating oil of
greater than about 5 ppm.
Other Lubricating Oil Additives
[0094] 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 antiwear additives, dispersants, detergents,
viscosity modifiers, corrosion inhibitors, rust inhibitors, metal
deactivators, extreme pressure additives, anti-seizure agents, wax
modifiers, viscosity modifiers, fluid-loss additives, seal
compatibility agents, lubricity agents, friction modifiers, other
antifoam 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); see also U.S. Pat. No. 7,704,930, the disclosure of which
is incorporated herein in its entirety. These additives are
commonly delivered with varying amounts of diluent oil, that may
range from 5 weight percent to 50 weight percent.
[0095] The additives useful in this disclosure do not have to be
soluble in the lubricating oils. Insoluble additives in oil can be
dispersed in the lubricating oils of this disclosure.
[0096] 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.
Antiwear Additives
[0097] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) can be a useful component of
the lubricating oils of this disclosure. ZDDP can be derived from
primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.2
where R.sup.1 and R.sup.2 are C.sub.1-C.sub.18 alkyl groups,
preferably C.sub.2-C.sub.12 alkyl groups. These alkyl groups may be
straight chain or branched. Alcohols used in the ZDDP can be
2-propanol, butanol, secondary butanol, pentanols, hexanols such as
4-methyl-2-pentanol, n-hexanol, n-octanol, 2-ethyl hexanol,
alkylated phenols, and the like. Mixtures of secondary alcohols or
of primary and secondary alcohol can be preferred. Alkyl aryl
groups may also be used.
[0098] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 677A", "LZ 1095" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "HITEC
7169".
[0099] The ZDDP is typically used in amounts of from about 0.4
weight percent to about 1.2 weight percent, preferably from about
0.5 weight percent to about 1.0 weight percent, and more preferably
from about 0.6 weight percent to about 0.8 weight percent, based on
the total weight of the lubricating oil, although more or less can
often be used advantageously. Preferably, the ZDDP is a secondary
ZDDP and present in an amount of from about 0.6 to 1.0 weight
percent of the total weight of the lubricating oil.
[0100] Low phosphorus engine oil formulations are included in this
disclosure. For such formulations, the phosphorus content is
typically less than about 0.12 weight percent preferably less than
about 0.10 weight percent and most preferably less than about 0.085
weight percent.
Dispersants
[0101] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
used in the formulation of the lubricating oil 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 herein form ash upon combustion.
[0102] 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.
[0103] A particularly useful class of dispersants are the
(poly)alkenylsuccinic derivatives, typically produced by the
reaction of a long chain hydrocarbyl substituted succinic compound,
usually a hydrocarbyl substituted succinic anhydride, with a
polyhydroxy or polyamino compound. The long chain hydrocarbyl 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.
[0104] Hydrocarbyl-substituted succinic acid and
hydrocarbyl-substituted succinic anhydride derivatives are useful
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.
[0105] Succinimides are formed by the condensation reaction between
hydrocarbyl substituted succinic anhydrides and amines. Molar
ratios can vary depending on the polyamine. For example, the molar
ratio of hydrocarbyl substituted succinic anhydride to TEPA can
vary from about 1:1 to about 5:1. Representative examples are shown
in U.S. Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746;
3,322,670; and 3,652,616, 3,948,800; and Canada Patent No.
1,094,044.
[0106] Succinate esters are formed by the condensation reaction
between hydrocarbyl substituted succinic anhydrides and alcohols or
polyols. Molar ratios can vary depending on the alcohol or polyol
used. For example, the condensation product of a hydrocarbyl
substituted succinic anhydride and pentaerythritol is a useful
dispersant.
[0107] Succinate ester amides are formed by condensation reaction
between hydrocarbyl substituted 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. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0108] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500 or more. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid. The above
products can also be post reacted with boron compounds such as
boric acid, borate esters or highly borated dispersants, to form
borated dispersants generally having from about 0.1 to about 5
moles of boron per mole of dispersant reaction product.
[0109] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, which is incorporated herein by reference. 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. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0110] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this disclosure can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HNR.sub.2 group-containing reactants.
[0111] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197.
[0112] 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
about 500 to about 5000, or from about 1000 to about 3000, or about
1000 to about 2000, or a mixture of such hydrocarbylene groups,
often with high terminal vinylic groups. Other preferred
dispersants include succinic acid-esters and amides,
alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components.
[0113] Polymethacrylate or polyacrylate derivatives are another
class of dispersants. These dispersants are typically prepared by
reacting a nitrogen containing monomer and a methacrylic or acrylic
acid esters containing 5-25 carbon atoms in the ester group.
Representative examples are shown in U.S. Pat. Nos. 2,100,993, and
6,323,164. Polymethacrylate and polyacrylate dispersants are
normally used as multifunctional viscosity modifiers. The lower
molecular weight versions can be used as lubricant dispersants or
fuel detergents.
[0114] Illustrative preferred dispersants useful in this disclosure
include those derived from polyalkenyl-substituted mono- or
dicarboxylic acid, anhydride or ester, which dispersant has a
polyalkenyl moiety with a number average molecular weight of at
least 900 and from greater than 1.3 to 1.7, preferably from greater
than 1.3 to 1.6, most preferably from greater than 1.3 to 1.5,
functional groups (mono- or dicarboxylic acid producing moieties)
per polyalkenyl moiety (a medium functionality dispersant).
Functionality (F) can be determined according to the following
formula:
F=(SAP.times.M.sub.n)/((112,200.times.A.I.)-(SAP.times.98))
wherein SAP is the saponification number (i.e., the number of
milligrams of KOH consumed in the complete neutralization of the
acid groups in one gram of the succinic-containing reaction
product, as determined according to ASTM D94); M.sub.n is the
number average molecular weight of the starting olefin polymer; and
A.I. is the percent active ingredient of the succinic-containing
reaction product (the remainder being unreacted olefin polymer,
succinic anhydride and diluent).
[0115] The polyalkenyl moiety of the dispersant may have a number
average molecular weight of at least 900, suitably at least 1500,
preferably between 1800 and 3000, such as between 2000 and 2800,
more preferably from about 2100 to 2500, and most preferably from
about 2200 to about 2400. The molecular weight of a dispersant is
generally expressed in terms of the molecular weight of the
polyalkenyl moiety. This is because the precise molecular weight
range of the dispersant depends on numerous parameters including
the type of polymer used to derive the dispersant, the number of
functional groups, and the type of nucleophilic group employed.
[0116] Polymer molecular weight, specifically M.sub.n, can be
determined by various known techniques. One convenient method is
gel permeation chromatography (GPC), which additionally provides
molecular weight distribution information (see W. W. Yau, J. J.
Kirkland and D. D. Bly, "Modern Size Exclusion Liquid
Chromatography", John Wiley and Sons, New York, 1979). Another
useful method for determining molecular weight, particularly for
lower molecular weight polymers, is vapor pressure osmometry (e.g.,
ASTM D3592).
[0117] The polyalkenyl moiety in a dispersant preferably has a
narrow molecular weight distribution (MWD), also referred to as
polydispersity, as determined by the ratio of weight average
molecular weight (M.sub.w) to number average molecular weight
(M.sub.n). Polymers having a M.sub.w/M.sub.n of less than 2.2,
preferably less than 2.0, are most desirable. Suitable polymers
have a polydispersity of from about 1.5 to 2.1, preferably from
about 1.6 to about 1.8.
[0118] Suitable polyalkenes employed in the formation of the
dispersants include homopolymers, interpolymers or lower molecular
weight hydrocarbons. One family of such polymers comprise polymers
of ethylene and/or at least one C.sub.3 to C.sub.2 alpha-olefin
having the formula H.sub.2C.dbd.CHR.sup.1 wherein R.sup.1 is a
straight or branched chain alkyl radical comprising 1 to 26 carbon
atoms and wherein the polymer contains carbon-to-carbon
unsaturation, and a high degree of terminal ethenylidene
unsaturation. Preferably, such polymers comprise interpolymers of
ethylene and at least one alpha-olefin of the above formula,
wherein R.sup.1 is alkyl of from 1 to 18 carbon atoms, and more
preferably is alkyl of from 1 to 8 carbon atoms, and more
preferably still of from 1 to 2 carbon atoms.
[0119] Another useful class of polymers is polymers prepared by
cationic polymerization of monomers such as isobutene and styrene.
Common polymers from this class include polyisobutenes obtained by
polymerization of a C.sub.4 refinery stream having a butene content
of 35 to 75% by wt., and an isobutene content of 30 to 60% by wt. A
preferred source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feedstocks are disclosed in
the art such as in U.S. Pat. No. 4,952,739. A preferred embodiment
utilizes polyisobutylene prepared from a pure isobutylene stream or
a Raffinate I stream to prepare reactive isobutylene polymers with
terminal vinylidene olefins. Polyisobutene polymers that may be
employed are generally based on a polymer chain of from 1500 to
3000.
[0120] The dispersant(s) are preferably non-polymeric (e.g., mono-
or bis-succinimides). Such dispersants can be prepared by
conventional processes such as disclosed in U.S. Patent Application
Publication No. 2008/0020950, the disclosure of which is
incorporated herein by reference.
[0121] The dispersant(s) can be borated by conventional means, as
generally disclosed in U.S. Pat. Nos. 3,087,936, 3,254,025 and
5,430,105.
[0122] Such dispersants may be used in an amount of about 0.01 to
20 weight percent or 0.01 to 10 weight percent, preferably about
0.5 to 8 weight percent, or more preferably 0.5 to 4 weight
percent. Or such dispersants may be used in an amount of about 2 to
12 weight percent, preferably about 4 to 10 weight percent, or more
preferably 6 to 9 weight percent. On an active ingredient basis,
such additives may be used in an amount of about 0.06 to 14 weight
percent, preferably about 0.3 to 6 weight percent. The hydrocarbon
portion of the dispersant atoms can range from C.sub.60 to
C.sub.1000, or from C.sub.70 to C.sub.300, or from C.sub.70 to
C.sub.200. These dispersants may contain both neutral and basic
nitrogen, and mixtures of both. Dispersants can be end-capped by
borates and/or cyclic carbonates. Nitrogen content in the finished
oil can vary from about 200 ppm by weight to about 2000 ppm by
weight, preferably from about 200 ppm by weight to about 1200 ppm
by weight. Basic nitrogen can vary from about 100 ppm by weight to
about 1000 ppm by weight, preferably from about 100 ppm by weight
to about 600 ppm by weight.
[0123] As used herein, the dispersant concentrations are given on
an "as delivered" basis. Typically, the active dispersant is
delivered with a process oil. The "as delivered" dispersant
typically contains from about 20 weight percent to about 80 weight
percent, or from about 40 weight percent to about 60 weight
percent, of active dispersant in the "as delivered" dispersant
product.
Detergents
[0124] Illustrative detergents useful in this disclosure include,
for example, alkali metal detergents, alkaline earth metal
detergents, or mixtures of one or more alkali metal detergents and
one or more alkaline earth metal detergents. A typical detergent is
an anionic material that contains a long chain hydrophobic portion
of the molecule and a smaller anionic or oleophobic hydrophilic
portion of the molecule. The anionic portion of the detergent is
typically derived from an organic acid such as a sulfur-containing
acid, carboxylic acid (e.g., salicylic acid), phosphorus-containing
acid, phenol, or mixtures thereof. The counterion is typically an
alkaline earth or alkali metal. The detergent can be overbased as
described herein.
[0125] The detergent is preferably a metal salt of an organic or
inorganic acid, a metal salt of a phenol, or mixtures thereof. The
metal is preferably selected from an alkali metal, an alkaline
earth metal, and mixtures thereof. The organic or inorganic acid is
selected from an aliphatic organic or inorganic acid, a
cycloaliphatic organic or inorganic acid, an aromatic organic or
inorganic acid, and mixtures thereof.
[0126] The metal is preferably selected from an alkali metal, an
alkaline earth metal, and mixtures thereof. More preferably, the
metal is selected from calcium (Ca), magnesium (Mg), and mixtures
thereof.
[0127] The organic acid or inorganic acid is preferably selected
from a sulfur-containing acid, a carboxylic acid, a
phosphorus-containing acid, and mixtures thereof.
[0128] Preferably, the metal salt of an organic or inorganic acid
or the metal salt of a phenol comprises calcium phenate, calcium
sulfonate, calcium salicylate, magnesium phenate, magnesium
sulfonate, magnesium salicylate, an overbased detergent, and
mixtures thereof.
[0129] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased. These detergents can be used in
mixtures of neutral, overbased, highly overbased calcium
salicylate, sulfonates, phenates and/or magnesium salicylate,
sulfonates, phenates. The TBN ranges can vary from low, medium to
high TBN products, including as low as 0 to as high as 600.
Preferably the TBN delivered by the detergent is between 1 and 20.
More preferably between 1 and 12. Mixtures of low, medium, high TBN
can be used, along with mixtures of calcium and magnesium metal
based detergents, and including sulfonates, phenates, salicylates,
and carboxylates. A detergent mixture with a metal ratio of 1, in
conjunction of a detergent with a metal ratio of 2, and as high as
a detergent with a metal ratio of 5, can be used. Borated
detergents can also be used.
[0130] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH).sub.2, BaO, Ba(OH).sub.2,
MgO, Mg(OH).sub.2, for example) with an alkyl phenol or sulfurized
alkylphenol. Useful alkyl groups include straight chain or branched
C.sub.1-C.sub.30 alkyl groups, preferably, C.sub.4-C.sub.20 or
mixtures thereof. Examples of suitable phenols include
isobutylphenol, 2-ethylhexylphenol, nonylphenol, dodecyl phenol,
and the like. It should be noted that starting alkylphenols may
contain more than one alkyl substituent that are each independently
straight chain or branched and can be used from 0.5 to 6 weight
percent. When a non-sulfurized alkylphenol is used, the sulfurized
product may be obtained by methods well known in the art. These
methods include heating a mixture of alkylphenol and sulfurizing
agent (including elemental sulfur, sulfur halides such as sulfur
dichloride, and the like) and then reacting the sulfurized phenol
with an alkaline earth metal base.
[0131] In accordance with this disclosure, metal salts of
carboxylic acids are preferred detergents. These carboxylic acid
detergents may be prepared by reacting a basic metal compound with
at least one carboxylic acid and removing free water from the
reaction product. These compounds may be overbased to produce the
desired TBN level. Detergents made from salicylic acid are one
preferred class of detergents derived from carboxylic acids. Useful
salicylates include long chain alkyl salicylates. One useful family
of compositions is of the formula
##STR00001##
where R is an alkyl group having 1 to about 30 carbon atoms, n is
an integer from 1 to 4, and M is an alkaline earth metal. Preferred
R groups are alkyl chains of at least C.sub.11, preferably C.sub.13
or greater. R may be optionally substituted with substituents that
do not interfere with the detergent's function. M is preferably,
calcium, magnesium, barium, or mixtures thereof. More preferably, M
is calcium.
[0132] Hydrocarbyl-substituted salicylic acids may be prepared from
phenols by the Kolbe reaction (see U.S. Pat. No. 3,595,791). The
metal salts of the hydrocarbyl-substituted salicylic acids may be
prepared by double decomposition of a metal salt in a polar solvent
such as water or alcohol.
[0133] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0134] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039.
[0135] Preferred detergents include calcium sulfonates, magnesium
sulfonates, calcium salicylates, magnesium salicylates, calcium
phenates, magnesium phenates, and other related components
(including borated detergents), and mixtures thereof. Preferred
mixtures of detergents include magnesium sulfonate and calcium
salicylate, magnesium sulfonate and calcium sulfonate, magnesium
sulfonate and calcium phenate, calcium phenate and calcium
salicylate, calcium phenate and calcium sulfonate, calcium phenate
and magnesium salicylate, calcium phenate and magnesium phenate.
Overbased detergents are also preferred.
[0136] The detergent concentration in the lubricating oils of this
disclosure can range from about 0.5 to about 6.0 weight percent,
preferably about 0.6 to 5.0 weight percent, and more preferably
from about 0.8 weight percent to about 4.0 weight percent, based on
the total weight of the lubricating oil.
[0137] As used herein, the detergent concentrations are given on an
"as delivered" basis. Typically, the active detergent is delivered
with a process oil. The "as delivered" detergent typically contains
from about 20 weight percent to about 100 weight percent, or from
about 40 weight percent to about 60 weight percent, of active
detergent in the "as delivered" detergent product.
Viscosity Modifiers
[0138] Viscosity modifiers (also known as viscosity index improvers
(VI improvers), and viscosity improvers) can be included in the
lubricant compositions of this disclosure.
[0139] Viscosity modifiers provide lubricants with high and low
temperature operability. These additives impart shear stability at
elevated temperatures and acceptable viscosity at low
temperatures.
[0140] Suitable viscosity modifiers include high molecular weight
hydrocarbons, polyesters and viscosity modifier dispersants that
function as both a viscosity modifier and a dispersant. Typical
molecular weights of these polymers are between about 10,000 to
1,500,000, more typically about 20,000 to 1,200,000, and even more
typically between about 50,000 and 1,000,000.
[0141] Examples of suitable viscosity modifiers are linear or
star-shaped polymers and copolymers of methacrylate, butadiene,
olefins, or alkylated styrenes. Polyisobutylene is a commonly used
viscosity modifier. Another suitable viscosity modifier is
polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity modifiers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
50,000 to 200,000 molecular weight.
[0142] Olefin copolymers are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921" and "PARATONE.RTM. 8941"); from Afton
Chemical Corporation under the trade designation "HiTEC.RTM." (such
as "HiTEC.RTM. 5850B"; and from The Lubrizol Corporation under the
trade designation "Lubrizol.RTM. 7067C". Hydrogenated polyisoprene
star polymers are commercially available from Infineum
International Limited, e.g., under the trade designation "SV200"
and "SV600". Hydrogenated diene-styrene block copolymers are
commercially available from Infineum International Limited, e.g.,
under the trade designation "SV 50".
[0143] The polymethacrylate or polyacrylate polymers can be linear
polymers which are available from Evnoik Industries under the trade
designation "Viscoplex.RTM." (e.g., Viscoplex 6-954) or star
polymers which are available from Lubrizol Corporation under the
trade designation Asteric.TM. (e.g., Lubrizol 87708 and Lubrizol
87725).
[0144] Illustrative vinyl aromatic-containing polymers useful in
this disclosure may be derived predominantly from vinyl aromatic
hydrocarbon monomer. Illustrative vinyl aromatic-containing
copolymers useful in this disclosure may be represented by the
following general formula:
A-B
wherein A is a polymeric block derived predominantly from vinyl
aromatic hydrocarbon monomer, and B is a polymeric block derived
predominantly from conjugated diene monomer.
[0145] In an embodiment of this disclosure, the viscosity modifiers
may be used in an amount of less than about 10 weight percent,
preferably less than about 7 weight percent, more preferably less
than about 4 weight percent, and in certain instances, may be used
at less than 2 weight percent, preferably less than about 1 weight
percent, and more preferably less than about 0.5 weight percent,
based on the total weight of the formulated oil or lubricating
engine oil. Viscosity modifiers are typically added as
concentrates, in large amounts of diluent oil.
[0146] As used herein, the viscosity modifier concentrations are
given on an "as delivered" basis. Typically, the active polymer is
delivered with a diluent oil. The "as delivered" viscosity modifier
typically contains from 20 weight percent to 75 weight percent of
an active polymer for polymethacrylate or polyacrylate polymers, or
from 8 weight percent to 20 weight percent of an active polymer for
olefin copolymers, hydrogenated polyisoprene star polymers, or
hydrogenated diene-styrene block copolymers, in the "as delivered"
polymer concentrate.
Antioxidants
[0147] Antioxidants retard the oxidative degradation of base oils
during service. Such degradation may result in deposits on metal
surfaces, the presence of sludge, or a viscosity increase in the
lubricant. One skilled in the art knows a wide variety of oxidation
inhibitors that are useful in lubricating oil compositions. See,
Klamann in Lubricants and Related Products, op cite, and U.S. Pat.
Nos. 4,798,684 and 5,084,197, for example.
[0148] Useful antioxidants include hindered phenols. These phenolic
antioxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones 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 antioxidants include the hindered phenols
substituted with C.sub.6+ 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; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant disclosure. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2'-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0149] Effective amounts of one or more catalytic antioxidants may
also be used. The catalytic antioxidants comprise an effective
amount of a) one or more oil soluble polymetal organic compounds;
and, effective amounts of b) one or more substituted
N,N'-diaryl-o-phenylenediamine compounds or c) one or more hindered
phenol compounds; or a combination of both b) and c). Catalytic
antioxidants are more fully described in U.S. Pat. No. 8,048,833,
herein incorporated by reference in its entirety.
[0150] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: 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)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 about
20 carbon atoms, and preferably contains from about 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.
[0151] Typical aromatic amines antioxidants have alkyl substituent
groups of at least about 6 carbon atoms. Examples of aliphatic
groups include hexyl, heptyl, octyl, nonyl, and decyl. Generally,
the aliphatic groups will not contain more than about 14 carbon
atoms. The general types of amine antioxidants useful in the
present compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present disclosure
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0152] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0153] Preferred antioxidants include hindered phenols, arylamines.
These antioxidants may be used individually by type or in
combination with one another. Such additives may be used in an
amount of about 0.01 to 5 weight percent, preferably about 0.01 to
1.5 weight percent, more preferably zero to less than 1.5 weight
percent, more preferably zero to less than 1 weight percent.
Pour Point Depressants (PPDs)
[0154] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
disclosure if desired. These pour point depressant may be added to
lubricating compositions of the present disclosure to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
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. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Such additives may be
used in an amount of about 0.01 to 5 weight percent, preferably
about 0.01 to 1.5 weight percent.
Seal Compatibility Agents
[0155] 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. Such additives may be used in an amount of
about 0.01
Other Antifoam Agents
[0156] Antifoam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical antifoam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Antifoam 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 weight
percent and often less than 0.1 weight percent.
Inhibitors and Antirust Additives
[0157] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. A wide variety of these are
commercially available.
[0158] 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 metal
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 about 0.01 to 5 weight percent, preferably
about 0.01 to 1.5 weight percent.
Antiwear Additives
[0159] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) can be a useful component of
the lubricating oils of this disclosure. ZDDP can be derived from
primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.2
where R.sup.1 and R.sup.2 are C.sub.1-C.sub.18 alkyl groups,
preferably C.sub.2-C.sub.12 alkyl groups. These alkyl groups may be
straight chain or branched. Alcohols used in the ZDDP can be
propanol, 2-propanol, butanol, secondary butanol, pentanols,
hexanols such as 4-methyl-2-pentanol, n-hexanol, n-octanol, 2-ethyl
hexanol, alkylated phenols, and the like. Mixtures of secondary
alcohols or of primary and secondary alcohol can be preferred.
Alkyl aryl groups may also be used.
[0160] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 677A", "LZ 1095" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "HITEC
7169".
[0161] The ZDDP is typically used in amounts of from about 0.3
weight percent to about 1.5 weight percent, preferably from about
0.4 weight percent to about 1.2 weight percent, more preferably
from about 0.5 weight percent to about 1.0 weight percent, and even
more preferably from about 0.6 weight percent to about 0.8 weight
percent, based on the total weight of the lubricating oil, although
more or less can often be used advantageously. Preferably, the ZDDP
is a secondary ZDDP and present in an amount of from about 0.6 to
1.0 weight percent of the total weight of the lubricating oil.
Friction Modifiers
[0162] A friction modifier is any material or materials that can
alter the coefficient of friction of a surface lubricated by any
lubricant or fluid containing such material(s). Friction modifiers,
also known as friction reducers, or lubricity agents or oiliness
agents, and other such agents that change the ability of base oils,
formulated lubricant compositions, or functional fluids, to modify
the coefficient of friction of a lubricated surface may be
effectively used in combination with the base oils or lubricant
compositions of the present disclosure if desired. Friction
modifiers that lower the coefficient of friction are particularly
advantageous in combination with the base oils and lube
compositions of this disclosure.
[0163] Illustrative friction modifiers may include, for example,
organometallic compounds or materials, or mixtures thereof.
Illustrative organometallic friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, molybdenum amine, molybdenum diamine, an
organotungstenate, a molybdenum dithiocarbamate, molybdenum
dithiophosphates, molybdenum amine complexes, molybdenum
carboxylates, and the like, and mixtures thereof. Similar tungsten
based compounds may be preferable.
[0164] Other illustrative friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, alkoxylated fatty acid esters, alkanolamides, polyol fatty
acid esters, borated glycerol fatty acid
[0165] Illustrative alkoxylated fatty acid esters include, for
example, polyoxyethylene stearate, fatty acid polyglycol ester, and
the like. These can include polyoxypropylene stearate,
polyoxybutylene stearate, polyoxyethylene isosterate,
polyoxypropylene isostearate, polyoxyethylene palmitate, and the
like.
[0166] Illustrative alkanolamides include, for example, lauric acid
diethylalkanolamide, palmic acid diethylalkanolamide, and the like.
These can include oleic acid diethyalkanolamide, stearic acid
diethylalkanolamide, oleic acid diethylalkanolamide,
polyethoxylated hydrocarbylamides, polypropoxylated
hydrocarbylamides, and the like.
[0167] Illustrative polyol fatty acid esters include, for example,
glycerol mono-oleate, saturated mono-, di-, and tri-glyceride
esters, glycerol mono-stearate, and the like. These can include
polyol esters, hydroxyl-containing polyol esters, and the like.
[0168] Illustrative borated glycerol fatty acid esters include, for
example, borated glycerol mono-oleate, borated saturated mono-,
di-, and tri-glyceride esters, borated glycerol mono-sterate, and
the like. In addition to glycerol polyols, these can include
trimethylolpropane, pentaerythritol, sorbitan, and the like. These
esters can be polyol monocarboxylate esters, polyol dicarboxylate
esters, and on occasion polyoltricarboxylate esters. Preferred can
be the glycerol mono-oleates, glycerol dioleates, glycerol
trioleates, glycerol monostearates, glycerol distearates, and
glycerol tristearates and the corresponding glycerol
monopalmitates, glycerol dipalmitates, and glycerol tripalmitates,
and the respective isostearates, linoleates, and the like. On
occasion the glycerol esters can be preferred as well as mixtures
containing any of these. Ethoxylated, propoxylated, butoxylated
fatty acid esters of polyols, especially using glycerol as
underlying polyol can be preferred.
[0169] Illustrative fatty alcohol ethers include, for example,
stearyl ether, myristyl ether, and the like. Alcohols, including
those that have carbon numbers from C.sub.3 to C.sub.50, can be
ethoxylated, propoxylated, or butoxylated to form the corresponding
fatty alkyl ethers. The underlying alcohol portion can preferably
be stearyl, myristyl, C.sub.11-C.sub.13 hydrocarbon, oleyl,
isosteryl, and the like.
[0170] The lubricating oils of this disclosure exhibit desired
properties, e.g., wear control, in the presence or absence of a
friction modifier.
[0171] Useful concentrations of friction modifiers may range from
0.01 weight percent to 5 weight percent, or about 0.1 weight
percent to about 2.5 weight percent, or about 0.1 weight percent to
about 1.5 weight percent, or about 0.1 weight percent to about 1
weight percent. Concentrations of molybdenum-containing materials
are often described in terms of Mo metal concentration.
Advantageous concentrations of Mo may range from 25 ppm to 700 ppm
or more, and often with a preferred range of 50-200 ppm. Friction
modifiers of all types may be used alone or in mixtures with the
materials of this disclosure. Often mixtures of two or more
friction modifiers, or mixtures of friction modifier(s) with
alternate surface active material(s), are also desirable.
[0172] 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.
[0173] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 1 below.
[0174] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating oil composition.
[0175] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 1 below.
[0176] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating oil composition.
TABLE-US-00002 TABLE 1 Typical Amounts of Other Lubricating Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Dispersant 0.1-20 0.1-8 Detergent 0.1-20 0.1-8 Friction
Modifier 0.01-5 0.01-1.5 Antioxidant 0.1-5 0.1-1.5 Pour Point
Depressant 0.0-5 0.01-1.5 (PPD) Antifoam Agent (inventive 0.001-3
0.001-0.15 and conventional) Viscosity Modifier (solid 0.1-2 0.1-1
polymer basis) Antiwear 0.2-3 0.5-1 Inhibitor and Antirust 0.01-5
0.01-1.5
[0177] The foregoing additives are all commercially available
materials. These additives may be added independently but are
usually precombined in packages which can be obtained from
suppliers of lubricant oil additives. Additive packages with a
variety of ingredients, proportions and characteristics are
available and selection of the appropriate package will take the
requisite use of the ultimate composition into account.
[0178] The following non-limiting examples are provided to
illustrate the disclosure.
EXAMPLES
[0179] Lubricating oils were prepared as described herein. All of
the ingredients used herein are commercially available.
[0180] The silicone antifoaming agents were delivered to the
lubricating oils at room temperature. This delivery method is
referred to in the Examples as the treatment procedure. Room
temperature vulcanized (RTV) silicone was used.
[0181] The additive package used in the lubricating oils included
conventional additives in conventional amounts. Conventional
additives used in the formulations were one or more of an
antioxidant, dispersant, pour point depressant, detergent,
corrosion inhibitor, metal deactivator, seal compatibility
additive, inhibitor, and anti-rust additive.
[0182] The lubricating oils were tested for high temperature
antifoaming performance in accordance with ASTM D6082 or ASTM D892
Sequence II. The temperature for ASTM D6082 was 150.degree. C., and
the temperature for ASTM D892 Sequence II was 93.5.degree. C.
[0183] RTV silicone immersed in lubricant at room temperature
delivered the high temperature antifoam agent. It has been found
that the silicone must be cured to deliver the agent. Uncured
silicone is ineffective. The cured silicone agent delivery method
is less susceptible to blending error, as the delivered silicone
agent is soluble and the rate of addition is fixed by
diffusion.
[0184] As graphically shown in FIG. 1, the silicone agent improves
foam performance (lower is better), as determined by ASTM D6082.
For the fresh oil, FIG. 1 shows the fully formulated engine (no
silicone agent) lubricant with poor antifoaming performance, as
determined by ASTM D6082. For the treated oils that include fresh
oil with different levels of exposure to heat and RTV silicone,
FIG. 1 shows improved foam performance (lower is better), as
determined by ASTM D6082.
[0185] FIG. 2 graphically shows ASTM D892 testing results in which
the low temperature Sequences (I and III) are impacted negatively.
However, the Sequence II performance is largely unchanged. This
allows targeting of high temperature foam performance in a manner
that was not previously available in applications where low
temperature foam performance is not required. This insight was used
to improve the Sequence II foam performance in oils with poor
Sequence II performance by treating them with RTV silicone. For the
treated oils that include fresh oil with different levels of
exposure to heat and RTV silicone, FIG. 2 shows improved foam
performance (lower is better), as determined by ASTM D892 Sequence
II.
[0186] FIG. 3 graphically shows ASTM D892 Sequence II testing
results for two treated lubricating oils with improved antifoaming
performance. For the treated oils that include fresh oil with
different levels of exposure to heat and amounts (ppm) of RTV
silicone, FIG. 3 shows improved foam performance (lower is better),
as determined by ASTM D892 Sequence II.
[0187] FIG. 4 graphically shows ASTM D892 testing results for two
treated lubricating oils with GTL 4 base stock and differently
sourced RTV silicone in which the low temperature Sequences (I and
III) are impacted negatively. However, the Sequence II performance
is largely unchanged. For the treated oils that include fresh oil
with GTL base stock and differently sourced RTV silicone and with
different levels of exposure to heat and amounts (ppm) of RTV
silicone, FIG. 4 shows improved foam performance (lower is better),
as determined by ASTM D892 Sequence II. As shown in FIG. 4,
differently sourced RTV silicones can affect the degree of improved
foam performance.
[0188] FIG. 5 shows gel permeation chromatography (GPC) of extracts
or leachates from differently sourced RTV silicone. As shown in
FIG. 5, differently sourced RTV silicone has different extracts or
leachates having different molecular weight distributions. FIG. 5
shows a bimodal molecular weight distribution for the differently
sourced RTV silicones.
[0189] FIG. 6 graphically shows the impact of temperature and
contacting time on the amount of leachates as measured by silicone
content as determined by ASTM D5185, in accordance with the
Examples.
[0190] 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.
[0191] 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.
[0192] 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