U.S. patent application number 13/947648 was filed with the patent office on 2014-02-06 for method for improving nitrile seal compatibility with lubricating oils.
This patent application is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. The applicant listed for this patent is David Joseph Baillargeon, Douglas Edward Deckman, Steven Michael Jetter, Anne M. Shough. Invention is credited to David Joseph Baillargeon, Douglas Edward Deckman, Steven Michael Jetter, Anne M. Shough.
Application Number | 20140038872 13/947648 |
Document ID | / |
Family ID | 48949271 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140038872 |
Kind Code |
A1 |
Deckman; Douglas Edward ; et
al. |
February 6, 2014 |
METHOD FOR IMPROVING NITRILE SEAL COMPATIBILITY WITH LUBRICATING
OILS
Abstract
Provided is a method of improving nitrile seal compatibility
with a lubricating oil in an engine lubricated with the lubricating
oil. The method includes using as the lubricating oil a formulated
oil comprising a lubricating oil base stock as a major component
and an alkylated aromatic base stock as a minor component. Nitrile
seal compatibility is improved as compared to nitrile seal
compatibility achieved using a lubricating oil containing a minor
component other than the alkylated aromatic base stock, e.g., an
ester. A lubricating engine oil comprising a lubricating oil base
stock as a major component and an alkylated aromatic base stock as
a minor component. The alkylated aromatic base stock is present in
an amount sufficient for the lubricating oil to exhibit improved
nitrile seal compatibility as compared to nitrile seal
compatibility achieved using a lubricating oil containing a minor
component other than the alkylated aromatic base stock.
Inventors: |
Deckman; Douglas Edward;
(Mullica Hill, NJ) ; Baillargeon; David Joseph;
(Cherry Hill, NJ) ; Shough; Anne M.; (New Castle,
DE) ; Jetter; Steven Michael; (East Windsor,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Deckman; Douglas Edward
Baillargeon; David Joseph
Shough; Anne M.
Jetter; Steven Michael |
Mullica Hill
Cherry Hill
New Castle
East Windsor |
NJ
NJ
DE
NJ |
US
US
US
US |
|
|
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
48949271 |
Appl. No.: |
13/947648 |
Filed: |
July 22, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61679915 |
Aug 6, 2012 |
|
|
|
Current U.S.
Class: |
508/572 ;
508/569; 508/581; 508/584; 508/585; 585/7 |
Current CPC
Class: |
C10M 2203/1025 20130101;
C10M 2205/223 20130101; C10M 2207/2805 20130101; C10M 2207/024
20130101; C10M 2205/173 20130101; C10M 2219/087 20130101; C10M
129/10 20130101; C10M 2207/2835 20130101; C10M 2223/045 20130101;
C10M 2205/0285 20130101; C10M 129/16 20130101; C10N 2030/36
20200501; C10M 2219/086 20130101; C10M 2207/025 20130101; C10N
2040/25 20130101; C10N 2020/011 20200501; C10M 107/02 20130101;
C10N 2030/45 20200501; C10M 135/04 20130101; C10N 2030/42 20200501;
C10M 2207/0406 20130101; C10M 129/12 20130101; C10M 2203/1006
20130101; C10M 2205/024 20130101; C10N 2020/02 20130101; C10N
2040/04 20130101; C10M 135/12 20130101; C10M 2223/045 20130101;
C10N 2010/04 20130101; C10M 2205/024 20130101; C10M 2205/028
20130101; C10N 2020/04 20130101; C10M 2205/024 20130101; C10N
2020/073 20200501; C10M 2203/1025 20130101; C10N 2020/02 20130101;
C10M 2205/024 20130101; C10M 2205/028 20130101; C10N 2020/04
20130101; C10M 2205/024 20130101; C10N 2020/073 20200501; C10M
2203/1025 20130101; C10N 2020/02 20130101; C10M 2223/045 20130101;
C10N 2010/04 20130101 |
Class at
Publication: |
508/572 ;
508/581; 508/585; 508/584; 508/569; 585/7 |
International
Class: |
C10M 135/12 20060101
C10M135/12; C10M 135/04 20060101 C10M135/04; C10M 129/10 20060101
C10M129/10; C10M 129/16 20060101 C10M129/16; C10M 129/12 20060101
C10M129/12 |
Claims
1. A method of improving nitrile seal compatibility with a
lubricating oil in an engine lubricated with the lubricating oil,
said method comprising using as the lubricating oil a formulated
oil comprising a lubricating oil base stock as a major component
and an alkylated aromatic base stock as a minor component; wherein
nitrile seal compatibility is improved as compared to nitrile seal
compatibility achieved using a lubricating oil containing a minor
component other than the alkylated aromatic base stock.
2. The method of claim 1 wherein the lubricating oil base stock
comprises a Group I, II, III, IV or V base oil stock, or mixtures
thereof.
3. The method of claim 1 wherein the lubricating oil base stock
comprises a poly alpha olefin (PAO) or gas-to-liquid (GTL) oil base
stock.
4. The method of claim 1 wherein the lubricating oil base stock is
present in an amount from 80 weight percent to 99 weight percent,
based on the total weight of the lubricating oil.
5. The method of claim 1 wherein the alkylated aromatic base stock
comprises an alkylated naphthalene, an alkylated benzene, or
mixtures thereof.
6. The method of claim 1 wherein the alkylated aromatic base stock
is selected from the group consisting of alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and mixtures thereof.
7. The method of claim 1 wherein the alkylated aromatic base stock
is mono-alkylated, dialkylated, or polyalkylated.
8. The method of claim 1 wherein the alkylated aromatic base stock
is an alkyl naphthalene selected from the group consisting of
mono-, di-, tri-, tetra-, or penta-C.sub.3 alkyl naphthalene,
C.sub.4 alkyl naphthalene, C.sub.5 alkylnaphthalene, C.sub.6 alkyl
naphthalene, C.sub.8 alkyl naphthalene, C.sub.10 alkyl naphthalene,
C.sub.1-2 alkyl naphthalene, C.sub.1-4 alkyl naphthalene, C.sub.1-6
alkyl naphthalene, C.sub.1-8 alkyl naphthalene, C.sub.10-C.sub.14
mixed alkyl naphthalene, C.sub.6-C.sub.18 mixed alkyl naphthalene,
or mono-, di-, tri-, tetra-, or penta C.sub.3, C.sub.4, C.sub.5,
C.sub.6, C.sub.8, C.sub.10, C.sub.12, C.sub.14, C.sub.16, C.sub.18
or mixture thereof alkyl monomethyl, dimethyl, ethyl, diethyl, or
methylethyl naphthalene, and mixtures thereof.
9. The method of claim 1 wherein the minor component other than the
alkylated aromatic base stock comprises an ester.
10. The method of claim 1 wherein the alkylated aromatic base stock
is present in an amount from 1 weight percent to 15 weight percent,
based on the total weight of the lubricating oil.
11. The method of claim 1 wherein the alkylated aromatic base stock
is present in an amount sufficient for the lubricating oil to
exhibit at least one of improved tensile strength (%) and
elongation at break (%) as determined by Nitrile-NBR34 (MB VDA
675301 Method).
12. The method of claim 1 wherein the lubricating oil further
comprises one or more of a viscosity index improver, antioxidant,
detergent, dispersant, pour point depressant, corrosion inhibitor,
metal deactivator, seal compatibility additive, antifoam agent,
inhibitor, anti-wear, friction modifier, and anti-rust
additive.
13. The method of claim 1 in which the lubricating oil is a
passenger vehicle engine oil.
14. A lubricating engine oil comprising a lubricating oil base
stock as a major component and an alkylated aromatic base stock as
a minor component; wherein the alkylated aromatic base stock is
present in an amount sufficient for the lubricating oil to exhibit
improved nitrile seal compatibility as compared to nitrile seal
compatibility achieved using a lubricating oil containing a minor
component other than the alkylated aromatic base stock.
15. The lubricating engine oil of claim 14 wherein the lubricating
oil base stock comprises a Group I, II, III, IV or V base oil
stock, or mixtures thereof.
16. The lubricating engine oil of claim 14 wherein the lubricating
oil base stock comprises a poly alpha olefin (PAO) or gas-to-liquid
(GTL) oil base stock.
17. The lubricating engine oil of claim 14 wherein the alkylated
aromatic base stock comprises an alkylated naphthalene, alkylated
benzene, or mixtures thereof.
18. The lubricating engine oil of claim 14 wherein the alkylated
aromatic base stock is selected from the group consisting of alkyl
benzenes, alkyl naphthalenes, alkyl diphenyl oxides, alkyl
naphthols, alkyl diphenyl sulfides, alkylated bis-phenol A,
alkylated thiodiphenol, and mixtures thereof.
19. The lubricating engine oil of claim 14 wherein the lubricating
oil base stock is present in an amount from 80 weight percent to 99
weight percent, based on the total weight of the lubricating oil,
and the alkylated aromatic base stock is present in an amount from
1 weight percent to 15 weight percent, based on the total weight of
the lubricating oil.
20. The lubricating engine oil of claim 14 wherein the alkylated
aromatic base stock is present in an amount sufficient for the
lubricating oil to exhibit at least one of improved change in
tensile strength (%) and elongation at break (%) as determined by
Nitrile-NBR34 (MB VDA 675301 Method).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/679,915, filed on Aug. 6, 2012; which is
incorporated herein in its entirety by reference.
FIELD
[0002] This disclosure relates to lubricating engines using
formulated lubricating oils that exhibit nitrile seal compatibility
in the engine. This disclosure relates to a method of improving the
seal compatibility performance of lubricating oil compositions used
in engine crankcases and transmissions, particularly lubricating
oil compositions having sulphur content, and to lubricating oils
having sulphur content that exhibit enhanced seal compatibility
performance in engines and transmissions containing nitrile rubber
seal materials.
BACKGROUND
[0003] Lubricants in commercial use today are prepared from a
variety of natural and synthetic base stocks admixed with various
additive packages and solvents depending upon their intended
application. The base stocks typically include mineral oils, poly
alpha olefins (PAO), gas-to-liquid base oils (GTL), silicone oils,
phosphate esters, diesters, polyol esters, and the like.
[0004] Lubricating oils used to lubricate internal combustion
engines and transmissions contain a major amount of a base oil of
lubricating viscosity, or a mixture of such oils, and additives
used to improve the performance characteristics of the oil. For
example, additives are used to improve detergency, to reduce engine
wear, to provide stability against heat and oxidation, to reduce
oil consumption, to inhibit corrosion, to act as a dispersant, and
to reduce friction loss. Some additives provide multiple benefits,
such as dispersant-viscosity modifiers. Many base oils contain
sulfur, and a number of extremely effective additives
conventionally used in engine and transmission lubricating oil
compositions, including zinc dialkyl dithiophosphates (ZDDP),
certain molybdenum-sulfur compounds, ashless dithiocarbamates and
sulfonate and some phenate detergents, also contain sulfur and
contribute to the overall sulfur content of such formulated
lubricants.
[0005] Modern internal combustion engines and transmissions include
numerous gaskets and other seals formed of nitrile rubber
materials. Lubricant sulfur has been found to contribute to the
deterioration of materials. Before certifying a crankcase lubricant
for use in their engines, engine manufacturers (oftentimes referred
to as "original equipment manufacturers" or "OEMs") require passage
of a number of performance tests, including tests for compatibility
with engine seal materials. Therefore, it would be desirable to
provide a method of improving the seal compatibility of lubricating
oils, particularly lubricating oils having significant sulfur
contents, and lubricating oils having significant sulfur contents
that provide improved seal-compatibility performance.
[0006] The present disclosure also provides many additional
advantages, which shall become apparent as described below.
SUMMARY
[0007] This disclosure relates to a method of improving the seal
compatibility performance of lubricating oil compositions used in
engine crankcases and transmissions, particularly lubricating oil
compositions having sulphur content, and to lubricating oils having
sulphur content that exhibit enhanced seal compatibility
performance in engines and transmissions containing nitrile rubber
seal materials.
[0008] This disclosure is directed in part to a method for
improving nitrile seal compatibility with a lubricating oil in an
engine lubricated with the lubricating oil. The method comprises
using as the lubricating oil a formulated oil comprising a
lubricating oil base stock as a major component and an alkylated
aromatic base stock as a minor component. Nitrile seal
compatibility is improved as compared to nitrile seal compatibility
achieved using a lubricating oil containing a minor component other
than the alkylated aromatic base stock, e.g., an ester.
[0009] This disclosure relates in part to a lubricating engine oil
comprising a lubricating oil base stock as a major component and an
alkylated aromatic base stock as a minor component. The alkylated
aromatic base stock is present in an amount sufficient for the
lubricating oil to exhibit improved nitrile seal compatibility as
compared to nitrile seal compatibility achieved using a lubricating
oil containing a minor component other than the alkylated aromatic
base stock, e.g., an ester.
[0010] In this disclosure, alkylated aromatic base stocks have been
found to improve nitrile seal compatibility with lubricating oils
when compared to alternate Group V base stocks such as esters.
[0011] Further objects, features and advantages of the present
disclosure will be understood by reference to the following
drawings and detailed description.
DETAILED DESCRIPTION
[0012] 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.
[0013] This disclosure provides lubricating oils useful as engine
oils and in other applications characterized by an excellent
nitrile seal compatibility characteristics. The lubricating oils
are based on high quality base stocks including a major portion of
a hydrocarbon base fluid such as a PAO or GTL with a secondary base
stock component which is preferably an alkylated aromatic fluid,
such as alkylated naphthalene. The Applicants have unexpectedly and
surprisingly discovered that certain engine oil compositions
including PAO or GTL base stocks with a secondary base stock
including one or more alkylated aromatic fluids yielded unexpected
improvements in nitrile seal compatibility characteristics. The
lubricating oil base stock can be any oil boiling in the lube oil
boiling range, typically between 100 to 600.degree. C. In the
present specification and claims, the terms base oil(s) and base
stock(s) are used interchangeably.
Lubricating Oil Base Stocks
[0014] A wide range of lubricating oils is known in the art.
Lubricating oils that are useful in the present disclosure are both
natural oils and synthetic oils. Natural and synthetic oils (or
mixtures thereof) can be used unrefined, refined, or rerefined (the
latter is also known as reclaimed or reprocessed oil). Unrefined
oils are those obtained directly from a natural or synthetic source
and used without added purification. These include shale oil
obtained directly from retorting operations, petroleum oil obtained
directly from primary distillation, and ester oil obtained directly
from an esterification process. Refined oils are similar to the
oils discussed for unrefined oils except refined oils are subjected
to one or more purification steps to improve the at least one
lubricating oil property. One skilled in the art is familiar with
many purification processes. These processes include solvent
extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as a feed stock.
[0015] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source; for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful in the present
disclosure. Natural oils vary also as to the method used for their
production and purification; for example, their distillation range
and whether they are straight run or cracked, hydrorefined, or
solvent extracted.
[0016] API Group I, II, III, IV and V base oil stocks are broad
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 generally have a
viscosity index of between 80 to 120 and contain greater than 0.03%
sulfur and less than 90% saturates. Group II base stocks generally
have a viscosity index of between 80 to 120, and contain less than
or equal to 0.03% sulfur and greater than or equal to 90%
saturates. Group III stock generally has a viscosity index greater
than 120 and contains less than or equal to 0.03% sulfur and
greater than 90% saturates. Group IV includes polyalphaolefins
(PAO). Group V base stocks include base stocks not included in
Groups I-IV. The table below summarizes properties of each of these
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 Includes
polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III or IV
[0017] Group II and/or Group III hydroprocessed or hydrocracked
base stocks, as well as synthetic oils such as polyalphaolefins,
alkyl aromatics and synthetic esters, i.e. Group IV and Group V
oils are also well known base stock oils.
[0018] Synthetic oils include hydrocarbon oil such as polymerized
and interpolymerized olefins (polybutylenes, polypropylenes,
propylene isobutylene copolymers, ethylene-olefin copolymers, and
ethylene-alphaolefin copolymers, for example). Polyalphaolefin
(PAO) oil base stocks, the Group IV API base stocks, are a commonly
used synthetic hydrocarbon oil. By way of example, PAOs derived
from C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or mixtures
thereof may be utilized. See U.S. Pat. Nos. 4,956,122; 4,827,064;
and 4,827,073, which are incorporated herein by reference in their
entirety. Group IV oils, that is, the PAO base stocks have
viscosity indices preferably greater than 130, more preferably
greater than 135, still more preferably greater than 140.
[0019] Esters in a minor amount may be useful in the lubricating
oils of this disclosure. Additive solvency and seal compatibility
characteristics may be secured by the use of esters such as the
esters of dibasic acids with monoalkanols and the polyol esters of
monocarboxylic acids. Esters of the former type include, for
example, the esters of dicarboxylic acids such as phthalic acid,
succinic acid, sebacic acid, fumaric acid, adipic acid, linoleic
acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic acid,
etc., with a variety of alcohols such as butyl alcohol, hexyl
alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, etc. Specific
examples of these types of esters include dibutyl adipate,
di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl
phthalate, dieicosyl sebacate, etc.
[0020] 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 (TMP), pentaerythritol and dipentaerythritol with alkanoic
acids containing at least 4 carbon atoms, preferably C.sub.5 to
C.sub.30 acids such as saturated straight chain fatty acids
including caprylic acid, capric acids, lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures of any of these materials.
[0021] Esters should be used in an amount such that the improved
nitrile seal compatibility provided by the lubricating oils of this
disclosure is not adversely affected. The esters preferably have a
D5293 viscosity of less than 10,000 cP at -35.degree. C.
[0022] Non-conventional or unconventional base stocks and/or base
oils include one or a mixture of base stock(s) and/or base oil(s)
derived from: (1) one or more gas-to-liquids (GTL) materials, as
well as (2) hydrodewaxed, or hydroisomerized/cat (and/or solvent)
dewaxed base stock(s) and/or base oils derived from synthetic wax,
natural wax or waxy feeds, mineral and/or non-mineral oil waxy feed
stocks such as gas oils, slack waxes (derived from the solvent
dewaxing of natural oils, mineral oils or synthetic oils; e.g.,
Fischer-Tropsch feed stocks), natural waxes, and waxy stocks such
as gas oils, waxy fuels hydrocracker bottoms, waxy raffinate,
hydrocrackate, thermal crackates, foots oil or other mineral,
mineral oil, or even non-petroleum oil derived waxy materials such
as waxy materials recovered from coal liquefaction or shale oil,
linear or branched hydrocarbyl compounds with carbon number of 20
or greater, preferably 30 or greater and mixtures of such base
stocks and/or base oils.
[0023] 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.
[0024] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from 2 mm.sup.2/s to 50 mm.sup.2/s (ASTM D445).
They are further characterized typically as having pour points of
-5.degree. C. to -40.degree. C. or lower (ASTM D97). They are also
characterized typically as having viscosity indices of 80 to 140 or
greater (ASTM D2270).
[0025] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) typically have very low sulfur and
nitrogen content, generally containing less than 10 ppm, and more
typically less than 5 ppm of each of these elements. The sulfur and
nitrogen content of GTL base stock(s) and/or base oil(s) obtained
from F-T material, especially F-T wax, is essentially nil. In
addition, the absence of phosphorous and aromatics make this
materially especially suitable for the formulation of low SAP
products.
[0026] 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.
[0027] 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).
[0028] 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, Group
V and Group VI oils and mixtures thereof, preferably API Group II,
Group III, Group IV, Group V and Group VI oils and mixtures
thereof, more preferably the Group III to Group VI base oils due to
their exceptional volatility, stability, viscometric and
cleanliness features. Minor quantities of Group I stock, such as
the amount used to dilute additives for blending into formulated
lube oil products, can be tolerated but should be kept to a
minimum, i.e. amounts only associated with their use as
diluent/carrier oil for additives used on an "as-received" basis.
Even in regard to the Group II stocks, it is preferred that the
Group II stock be in the higher quality range associated with that
stock, i.e. a Group II stock having a viscosity index in the range
100<VI<120.
[0029] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) and hydrodewaxed, or
hydroisomerized/cat (and/or solvent) dewaxed base stock(s) and/or
base oil(s) typically have very low sulfur and nitrogen content,
generally containing less than 10 ppm, and more typically less than
5 ppm of each of these elements. The sulfur and nitrogen content of
GTL base stock(s) and/or base oil(s) obtained from F-T material,
especially F-T wax, is essentially nil. In addition, the absence of
phosphorous and aromatics make this material especially suitable
for the formulation of low sulfur, sulfated ash, and phosphorus
(low SAP) products.
[0030] The base stock component can preferably be a mixture of one
or more of the API Group I, II, III, IV and V base oil stocks. The
base stock component of the present lubricating oils will typically
be from 80 to 99 weight percent of the total composition (all
proportions and percentages set out in this specification are by
weight unless the contrary is stated) and more usually in the range
of 90 to 99 weight percent.
Alkylated Aromatic Base Stock Components
[0031] Alkylated aromatic base stock components useful in this
disclosure include, for example, alkylated naphthalenes and
alkylated benzenes. The alkylated aromatic base stock can be any
hydrocarbyl molecule that contains at least 5% of its weight
derived from an aromatic moiety such as a benzenoid moiety or
naphthenoid moiety, or their derivatives. These alkylated aromatic
base stocks include alkyl benzenes, alkyl naphthalenes, alkyl
diphenyl oxides, alkyl naphthols, alkyl diphenyl sulfides,
alkylated bis-phenol A, alkylated thiodiphenol, and the like. The
alkylated aromatic base stock can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can range from C.sub.6
up to C.sub.60 with a range of C.sub.8 to C.sub.40 often being
preferred. A mixture of hydrocarbyl groups is often preferred. 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 5% of
the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to 50 cSt are
preferred, with viscosities of approximately 3.4 cSt to 20 cSt
often being more preferred for the alkylated aromatic base stock.
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.
[0032] Illustrative alkylated naphthalenes useful in the present
disclosure are described, for example, in U.S. Patent Publication
No. 2008/0300157.
[0033] Examples of typical alkyl naphthalenes are mono-, di-, tri-,
tetra-, or penta-C.sub.3 alkyl naphthalene, C.sub.4 alkyl
naphthalene, C.sub.5 alkylnaphthalene, C.sub.6 alkyl naphthalene,
C.sub.8 alkyl naphthalene, C.sub.10 alkyl naphthalene, C.sub.1-2
alkyl naphthalene, C.sub.1-4 alkyl naphthalene, C.sub.1-6 alkyl
naphthalene, C.sub.1-8 alkyl naphthalene, etc., C.sub.10-C.sub.14
mixed alkyl naphthalene, C.sub.6-C.sub.18 mixed alkyl naphthalene,
or the mono-, di-, tri-, tetra-, or penta-C.sub.3, C.sub.4,
C.sub.5, C.sub.6, C.sub.8, C.sub.10, C.sub.12, C.sub.14, C.sub.16,
C.sub.18 or mixture thereof alkyl monomethyl, dimethyl, ethyl,
diethyl, or methylethyl naphthalene, or mixtures thereof. The alkyl
group can also be branched alkyl group with C.sub.10 to C.sub.300,
e.g., C.sub.24-C.sub.56 branched alkyl naphthalene,
C.sub.24-C.sub.56 branched alkyl mono-, di-, tri-, tetra- or
penta-C.sub.1-C.sub.4 naphthalene. These branched alkyl group
substituted naphthalenes or branched alkyl group substituted mono-,
di-, tri-, tetra- or penta-C.sub.1-C.sub.4 naphthalene can also be
used as mixtures with the previously recited materials. These
branched alkyl group can be prepared from oligomerization of small
olefins, such as C.sub.5 to C.sub.24 alpha- or internal-olefins.
When the branched alkyl group is very large (that is 8 to 300
carbons), usually only one or two of such alkyl groups are attached
to the naphthalene core. The alkyl groups on the naphthalene ring
can also be mixtures of the above alkyl groups. Sometimes mixed
alkyl groups are advantageous because they provide more improvement
of pour points and low temperature fluid properties. The fully
hydrogenated fluid alkylnaphthalenes can also be used for blending
with GTL base stock/base oil, but the alkyl naphthalenes are
preferred.
[0034] Typically the alkyl naphthalenes are prepared by alkylation
of naphthalene or short chain alkyl naphthalene, such as methyl or
di-methyl naphthalene, with olefins, alcohols or alkylchlorides of
6 to 24 carbons over acidic catalyst inducing typical
Friedel-Crafts catalysts. Typical Friedel-Crafts catalysts are
AlCl.sub.3, BF.sub.3, HT, zeolites, amorphous aluminosilicates,
acid clays, acidic metal oxides or metal salts, USY, etc.
[0035] Methods for the production of alkylnaphthalenes suitable for
use in the present disclosure are described in U.S. Pat. Nos.
5,034,563, 5,516,954, and 6,436,882, as well as in references cited
in those patents as well as taught elsewhere in the literature.
Because alkylated naphthalene synthesis techniques are well known
to those skilled in the art as well as being well documented in the
literature such techniques will not be further addressed
herein.
[0036] The naphthalene or mono- or di-substituted short chain alkyl
naphthalenes can be derived from any conventional
naphthalene-producing process from petroleum, petrochemical process
or coal process or source stream. Naphthalene-containing feeds can
be made from aromaticization of suitable streams available from the
F-T process. For example, aromatization of olefins or paraffins can
produce naphthalene or naphthalene-containing component. Many
medium or light cycle oils from petroleum refining processes
contain significant amounts of naphthalene, substituted
naphthalenes or naphthalene derivatives. Indeed, substituted
naphthalenes recovered from whatever source, if possessing up to
three alkyl carbons can be used as raw material to produce
alkylnaphthalene for this disclosure. Furthermore, alkylated
naphthalenes recovered from whatever source or processing can be
used in the present method, provided they possess kinematic
viscosities, VI, pour point, etc.
[0037] Suitable alkylated naphthalenes are available commercially
from ExxonMobil under the tradename Synesstic AN or from King
Industries under the tradename NA-Lube naphthalene-containing
fluids.
[0038] Illustrative alkylated benzenes useful in this disclosure
include, for example, those described in U.S. Patent Publication
2008/0300157. Alkylated benzenes having a viscosity at 100.degree.
C. of 1.5 to 600 cS, VI of 0 to 200 and pour point of 0.degree. C.
or less, preferably -15.degree. C. or less, more preferably
-25.degree. C. or less, still more preferably -35.degree. C. or
less, most preferably -60.degree. C. or less are useful for this
disclosure.
[0039] Illustrative monoalkylated benzenes include, for example,
linear C.sub.10 to C.sub.30 alkyl benzene or a C.sub.10-C.sub.300
branched alkyl benzene, preferably C.sub.10-C.sub.100 branched
alkyl benzene, more preferably C.sub.15-C.sub.50 branched alkyl
group. Illustrative miltialkylated benzenes include, for example,
those in which one or two of the alkyl groups can be small alkyl
radical of C.sub.1 to C.sub.5 alkyl group, preferably
C.sub.1-C.sub.2 alkyl group. The other alkyl group or groups can be
any combination of linear C.sub.10-C.sub.30 alkyl group, or
branched C.sub.10 and higher up to C.sub.300 alkyl group,
preferably C.sub.15-C.sub.50 branched alkyl group. These branched
large alkyl radicals can be prepared from the oligomerization or
polymerization of C.sub.3 to C.sub.20, internal or alpha-olefins or
mixture of these olefins. The total number of carbons in the alkyl
substituents ranged from C.sub.10 to C.sub.300. Preferred alkyl
benzene fluids can be prepared according to U.S. Pat. Nos.
6,071,864 and 6,491,809.
[0040] Included in this class of base stock blend components are,
for example, long chain alkylbenzenes and long chain alkyl
naphthalenes which are preferred materials since they are
hydrolytically stable and may therefore be used in combination with
the PAO component of the base stock in wet applications. The
alkylnaphthalenes are known materials and are described, for
example, in U.S. Pat. No. 4,714,794. The use of a mixture of
monoalkylated and polyalkylated naphthalene as a base for synthetic
functional fluids is also described in U.S. Pat. No. 4,604,491. The
preferred alkylnaphthalenes are those having a relatively long
chain alkyl group typically from 10 to 40 carbon atoms although
longer chains may be used if desired. Alkylnaphthalenes produced by
alkylating naphthalene with an olefin of 14 to 20 carbon atoms has
particularly good properties, especially when zeolites such as the
large pore size zeolites are used as the alkylating catalyst, as
described in U.S. Pat. No. 5,602,086. These alkylnaphthalenes are
predominantly monosubstituted naphthalenes with attachment of the
alkyl group taking place predominantly at the 1- or 2-position of
the alkyl chain. The presence of the long chain alkyl groups
confers good viscometric properties on the alkyl naphthalenes,
especially when used in combination with the PAO components which
are themselves materials of high viscosity index, low pour point
and good fluidity.
[0041] An alternative secondary blending stock is an alkylbenzene
or mixture of alkylbenzenes. The alkyl substituents in these fluids
are typically alkyl groups of 8 to 25 carbon atoms, usually from 10
to 18 carbon atoms and up to three such substituents may be
present, as described in ACS Petroleum Chemistry Preprint
1053-1058, "Poly n-Alkylbenzene Compounds: A Class of Thermally
Stable and Wide Liquid Range Fluids", Eapen et al, Phila. 1984.
Tri-alkyl benzenes may also be produced by the cyclodimerization of
1-alkynes of 8 to 12 carbon atoms as described in U.S. Pat. No.
5,055,626. Other alkylbenzenes are described in U.S. Pat. No.
4,658,072. Alkylbenzenes have been used as lubricant base stocks,
especially for low temperature applications. They are commercially
available from producers of linear alkylbenzenes (LABs) such as
Vista Chemical Co, Huntsman Chemical Co. as well as ChevronTexaco
and Nippon Oil Co. The linear alkylbenzenes typically have good low
pour points and low temperature viscosities and VI values greater
than 100 together with good solvency for additives. Other alkylated
aromatics which may be used when desirable are described, for
example, in "Synthetic Lubricants and High Performance Functional
Fluids", Dressler, H., chap 5, (R. L. Shubkin (Ed.)), Marcel
Dekker, N.Y. 1993.
[0042] Also included in this class and with very desirable
lubricating characteristics are the alkylated aromatic compounds
including the alkylated diphenyl compounds such as the alkylated
diphenyl oxides, alkylated diphenyl sulfides and alkylated diphenyl
methanes and the alkylated phenoxathins as well as the
alkylthiophenes, alkyl benzofurans and the ethers of
sulfur-containing aromatics. Lubricant blend components of this
type are described, for example, in U.S. Pat. Nos. 5,552,071;
5,171,195; 5,395,538; 5,344,578; and 5,371,248.
[0043] The alkylated aromatic base stock component can be a mixture
of one or more alkylated aromatic base stocks. The alkylated
aromatic base stock component is typically used in an amount from
1% to 15%, preferably 2% to 10%, and more preferably 4% to 8%,
depending on the application.
[0044] The alkylated aromatic base stock component is preferably
present in an amount sufficient for the lubricating oil to exhibit
improved nitrile seal compatibility with a lubricating oil in an
engine lubricated with the lubricating oil, as compared to nitrile
seal compatibility achieved using a lubricating oil containing
other than the alkylated aromatic base stock, preferably improved
change in tensile strength (%) and elongation at break (%) as
determined by Nitrile-NBR34 (MB VDA 675301 Method).
Other Additives
[0045] The formulated lubricating oil useful in the present
disclosure may additionally contain one or more of the other
commonly used lubricating oil performance additives including but
not limited to dispersants, other detergents, corrosion inhibitors,
rust inhibitors, metal deactivators, other anti-wear agents and/or
extreme pressure additives, anti-seizure agents, wax modifiers,
viscosity index improvers, viscosity modifiers, fluid-loss
additives, seal compatibility agents, other friction modifiers,
lubricity agents, anti-staining agents, chromophoric agents,
defoamants, demulsifiers, emulsifiers, densifiers, wetting agents,
gelling agents, tackiness agents, colorants, and others. For a
review of many commonly used additives, see Klamann in Lubricants
and Related Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN
0-89573-177-0. Reference is also made to "Lubricant Additives" by
M. W. Ranney, published by Noyes Data Corporation of Parkridge,
N.J. (1973).
[0046] 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.
Viscosity Improvers
[0047] Viscosity improvers (also known as Viscosity Index
modifiers, and VI improvers) increase the viscosity of the oil
composition at elevated temperatures which increases film
thickness, while having limited effect on viscosity at low
temperatures.
[0048] Suitable viscosity improvers include high molecular weight
hydrocarbons, polyesters and viscosity index improver dispersants
that function as both a viscosity index improver and a dispersant.
Typical molecular weights of these polymers are between 10,000 to
1,000,000, more typically 20,000 to 500,000, and even more
typically between 50,000 and 200,000.
[0049] Examples of suitable viscosity improvers are polymers and
copolymers of methacrylate, butadiene, olefins, or alkylated
styrenes. Polyisobutylene is a commonly used viscosity index
improver. Another suitable viscosity index improver is
polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity index improvers
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.
[0050] The amount of viscosity modifier may range from zero to 8 wt
%, preferably zero to 4 wt %, more preferably zero to 2 wt % based
on active ingredient and depending on the specific viscosity
modifier used.
Antioxidants
[0051] Typical antioxidant include phenolic antioxidants, aminic
antioxidants and oil-soluble copper complexes.
[0052] The phenolic antioxidants include sulfurized and
non-sulfurized phenolic antioxidants. The terms "phenolic type" or
"phenolic antioxidant" used herein includes compounds having one or
more than one hydroxyl group bound to an aromatic ring which may
itself be mononuclear, e.g., benzyl, or poly-nuclear, e.g.,
naphthyl and spiro aromatic compounds. Thus "phenol type" includes
phenol per se, catechol, resorcinol, hydroquinone, naphthol, etc.,
as well as alkyl or alkenyl and sulfurized alkyl or alkenyl
derivatives thereof, and bisphenol type compounds including such
bi-phenol compounds linked by alkylene bridges sulfuric bridges or
oxygen bridges. Alkyl phenols include mono- and poly-alkyl or
alkenyl phenols, the alkyl or alkenyl group containing from 3-100
carbons, preferably 4 to 50 carbons and sulfurized derivatives
thereof, the number of alkyl or alkenyl groups present in the
aromatic ring ranging from 1 to up to the available unsatisfied
valences of the aromatic ring remaining after counting the number
of hydroxyl groups bound to the aromatic ring.
[0053] Generally, therefore, the phenolic antioxidant may be
represented by the general formula:
(R).sub.x--Ar--(OH).sub.y
where Ar is selected from the group consisting of:
##STR00001##
wherein R is a C.sub.3-C.sub.100 alkyl or alkenyl group, a sulfur
substituted alkyl or alkenyl group, preferably a C.sub.4-C.sub.50
alkyl or alkenyl group or sulfur substituted alkyl or alkenyl
group, more preferably C.sub.3-C.sub.100 alkyl or sulfur
substituted alkyl group, most preferably a C.sub.4-C.sub.50 alkyl
group, R.sup.g is a C.sub.1-C.sub.100 alkylene or sulfur
substituted alkylene group, preferably a C.sub.2-C.sub.50 alkylene
or sulfur substituted alkylene group, more preferably a
C.sub.2-C.sub.2 alkylene or sulfur substituted alkylene group, y is
at least 1 to up to the available valences of Ar, x ranges from 0
to up to the available valances of Ar-y, z ranges from 1 to 10, n
ranges from 0 to 20, and m is 0 to 4 and p is 0 or 1, preferably y
ranges from 1 to 3, x ranges from 0 to 3, z ranges from 1 to 4 and
n ranges from 0 to 5, and p is O.
[0054] Preferred phenolic antioxidant compounds are the hindered
phenolics and phenolic esters which contain a sterically hindered
hydroxyl group, and these include those derivatives of dihydroxy
aryl compounds in which the hydroxyl groups are in the o- or
p-position to each other. Typical phenolic antioxidants include the
hindered phenols substituted with C.sub.1+ alkyl groups and the
alkylene coupled derivatives of these hindered phenols. Examples of
phenolic materials of this type 2-t-butyl-4-heptyl phenol;
2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecyl phenol;
2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;
2-methyl-6-t-butyl-4-heptyl phenol; 2-methyl-6-t-butyl-4-dodecyl
phenol; 2,6-di-t-butyl-4 methyl phenol; 2,6-di-t-butyl-4-ethyl
phenol; and 2,6-di-t-butyl 4 alkoxy phenol; and
##STR00002##
[0055] Phenolic type antioxidants are well known in the lubricating
industry and commercial examples such as Ethanox.RTM. 4710,
Irganox.RTM. 1076, Irganox.RTM. L1035, Irganox.RTM. 1010,
Irganox.RTM. L109, Irganox.RTM. L118, Irganox.RTM. L135 and the
like are familiar to those skilled in the art. The above is
presented only by way of exemplification, not limitation on the
type of phenolic antioxidants which can be used.
[0056] The phenolic antioxidant can be employed in an amount in the
range of 0.1 to 3 wt %, preferably 0.25 to 2.5 wt %, more
preferably 0.5 to 2 wt % on an active ingredient basis.
[0057] Aromatic amine antioxidants include phenyl-.alpha.-naphthyl
amine which is described by the following molecular structure:
##STR00003##
wherein le is hydrogen or a C.sub.1 to C.sub.14 linear or C.sub.3
to C.sub.14 branched alkyl group, preferably C.sub.1 to C.sub.10
linear or C.sub.3 to C.sub.10 branched alkyl group, more preferably
linear or branched C.sub.6 to C.sub.8 and n is an integer ranging
from 1 to 5 preferably 1. A particular example is Irganox L06.
[0058] Other aromatic amine antioxidants include other alkylated
and non-alkylated aromatic amines such as aromatic monoamines of
the formula R.sup.8R.sup.9R.sup.10N where R.sup.8 is an aliphatic,
aromatic or substituted aromatic group, R.sup.9 is an aromatic or a
substituted aromatic group, and R.sup.10 is H, alkyl, aryl or
R.sup.11S(O).sub.xR.sup.12 where R.sup.11 is an alkylene,
alkenylene, or aralkylene group, R.sup.12 is a higher alkyl group,
or an alkenyl, aryl, or alkaryl group, and x is 0, 1 or 2. The
aliphatic group R.sup.8 may contain from 1 to 20 carbon atoms, and
preferably contains from 6 to 12 carbon atoms. The aliphatic group
is a saturated aliphatic group. Preferably, both R.sup.8 and
R.sup.9 are aromatic or substituted aromatic groups, and the
aromatic group may be a fused ring aromatic group such as naphthyl.
Aromatic groups R.sup.8 and R.sup.9 may be joined together with
other groups such as S.
[0059] Typical aromatic amines antioxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 14 carbon atoms. The
general types of such other additional amine antioxidants which may
be present include diphenylamines, phenothiazines, imidodibenzyls
and diphenyl phenylene diamines Mixtures of two or more of such
other additional aromatic amines may also be present. Polymeric
amine antioxidants can also be used.
[0060] Another class of antioxidant used in lubricating oil
compositions and which may also be present are oil-soluble copper
compounds. Any oil-soluble suitable copper compound may be blended
into the lubricating oil. Examples of suitable copper antioxidants
include copper dihydrocarbyl thio- or dithio-phosphates and copper
salts of carboxylic acid (naturally occurring or synthetic). Other
suitable copper salts include copper dithiacarbamates, sulphonates,
phenates, and acetylacetonates. Basic, neutral, or acidic copper
Cu(I) and or Cu(II) salts derived from alkenyl succinic acids or
anhydrides are known to be particularly useful.
[0061] Such antioxidants may be used individually or as mixtures of
one or more types of antioxidants, the total amount employed being
an amount of 0.50 to 5 wt %, preferably 0.75 to 3 wt % (on an
as-received basis).
Detergents
[0062] In addition to the alkali or alkaline earth metal salicylate
detergent which is an optional component in the present disclosure,
other detergents may also be present. While such other detergents
can be present, it is preferred that the amount employed be such as
to not interfere with the synergistic effect attributable to the
presence of the salicylate. Therefore, most preferably such other
detergents are not employed.
[0063] If such additional detergents are present, they can include
alkali and alkaline earth metal phenates, sulfonates, carboxylates,
phosphonates and mixtures thereof. These supplemental detergents
can have total base number (TBN) ranging from neutral to highly
overbased, i.e. TBN of 0 to over 500, preferably 2 to 400, more
preferably 5 to 300, and they can be present either individually or
in combination with each other in an amount in the range of from 0
to 10 wt %, preferably 0.5 to 5 wt % (active ingredient) based on
the total weight of the formulated lubricating oil. As previously
stated, however, it is preferred that such other detergent not be
present in the formulation.
[0064] Such additional other detergents include by way of example
and not limitation calcium phenates, calcium sulfonates, magnesium
phenates, magnesium sulfonates and other related components
(including borated detergents).
Dispersants
[0065] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
may be ashless or ash-forming in nature. Preferably, the dispersant
is ashless. So-called ashless dispersants are organic materials
that form substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0066] 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.
[0067] A particularly useful class of dispersants are the
alkenylsuccinic derivatives, typically produced by the reaction of
a long chain substituted alkenyl succinic compound, usually a
substituted succinic anhydride, with a polyhydroxy or polyamino
compound. The long chain group constituting the oleophilic portion
of the molecule which confers solubility in the oil is normally a
polyisobutylene group. Many examples of this type of dispersant are
well known commercially and in the literature. Exemplary U.S.
patents describing such dispersants are U.S. Pat. Nos. 3,172,892;
3,215,707; 3,219,666; 3,316,177; 3,341,542; 3,444,170; 3,454,607;
3,541,012; 3,630,904; 3,632,511; 3,787,374 and 4,234,435. Other
types of dispersant are described in U.S. Pat. Nos. 3,036,003;
3,200,107; 3,254,025; 3,275,554; 3,438,757; 3,454,555; 3,565,804;
3,413,347; 3,697,574; 3,725,277; 3,725,480; 3,726,882; 4,454,059;
3,329,658; 3,449,250; 3,519,565; 3,666,730; 3,687,849; 3,702,300;
4,100,082; 5,705,458. A further description of dispersants may be
found, for example, in European Patent Application No. 471 071, to
which reference is made for this purpose.
[0068] Hydrocarbyl-substituted succinic acid compounds are popular
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0069] Succinimides are formed by the condensation reaction between
alkenyl succinic anhydrides and amines Molar ratios can vary
depending on the amine or polyamine. For example, the molar ratio
of alkenyl succinic anhydride to TEPA can vary from 1:1 to 5:1.
[0070] Succinate esters are formed by the condensation reaction
between alkenyl succinic anhydrides and alcohols or polyols. Molar
ratios can vary depending on the alcohol or polyol used. For
example, the condensation product of an alkenyl succinic anhydride
and pentaerythritol is a useful dispersant.
[0071] Succinate ester amides are formed by condensation reaction
between alkenyl succinic anhydrides and alkanol amines. For
example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine.
[0072] The molecular weight of the alkenyl succinic anhydrides will
typically range between 800 and 2,500. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid, and boron
compounds such as borate esters or highly borated dispersants. The
dispersants can be borated with from 0.1 to 5 moles of boron per
mole of dispersant reaction product.
[0073] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines Process aids and catalysts,
such as oleic acid and sulfonic acids, can also be part of the
reaction mixture. Molecular weights of the alkylphenols range from
800 to 2,500 or more.
[0074] Typical high molecular weight aliphatic acid modified
Mannich condensation products can be prepared from high molecular
weight alkyl-substituted hydroxyaromatics or HN(R).sub.2
group-containing reactants.
[0075] Examples of high molecular weight alkyl-substituted
hydroxyaromatic compounds are polypropylphenol, polybutylphenol,
and other polyalkylphenols. These polyalkylphenols can be obtained
by the alkylation, in the presence of an alkylating catalyst, such
as BF.sub.3, of phenol with high molecular weight polypropylene,
polybutylene, and other polyalkylene compounds to give alkyl
substituents on the benzene ring of phenol having an average
600-100,000 molecular weight.
[0076] Examples of HN(R).sub.2 group-containing reactants are
alkylene polyamines, principally polyethylene polyamines. Other
representative organic compounds containing at least one
HN(R).sub.2 group suitable for use in the preparation of Mannich
condensation products are well known and include the mono- and
di-amino alkanes and their substituted analogs, e.g., ethylamine
and diethanol amine; aromatic diamines, e.g., phenylene diamine,
diamino naphthalenes; heterocyclic amines, e.g., morpholine,
pyrrole, pyrrolidine, imidazole, imidazolidine, and piperidine;
melamine and their substituted analogs.
[0077] Examples of alkylene polyamine reactants include
ethylenediamine, diethylene triamine, triethylene tetraamine,
tetraethylene pentaamine, pentaethylene hexamine, hexaethylene
heptaamine, heptaethylene octaamine, octaethylene nonaamine,
nonaethylene decamine, and decaethylene undecamine and mixture of
such amines having nitrogen contents corresponding to the alkylene
polyamines, in the formula H.sub.2N--(Z--NH--).sub.nH, mentioned
before, Z is a divalent ethylene and n is 1 to 10 of the foregoing
formula. Corresponding propylene polyamines such as propylene
diamine and di-, tri-, tetra-, pentapropylene tri-, tetra-, penta-
and hexaamines are also suitable reactants. The alkylene polyamines
are usually obtained by the reaction of ammonia and dihalo alkanes,
such as dichloro alkanes. Thus the alkylene polyamines obtained
from the reaction of 2 to 11 moles of ammonia with 1 to 10 moles of
dichloroalkanes having 2 to 6 carbon atoms and the chlorines on
different carbons are suitable alkylene polyamine reactants.
[0078] Aldehyde reactants useful in the preparation of the high
molecular products useful in this disclosure include the aliphatic
aldehydes such as formaldehyde (also as paraformaldehyde and
formalin), acetaldehyde and aldol (.beta.-hydroxybutyraldehyde).
Formaldehyde or a formaldehyde-yielding reactant is preferred.
[0079] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
500 to 5000 or more or a mixture of such hydrocarbylene groups.
Other preferred dispersants include succinic acid-esters and
amides, alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components. Such additives may be
used in an amount of 0.1 to 20 wt %, preferably 0.1 to 8 wt %, more
preferably 1 to 6 wt % (on an as-received basis) based on the
weight of the total lubricant.
Pour Point Depressants
[0080] Conventional pour point depressants (also known as lube oil
flow improvers) may also be present. Pour point depressant may be
added to lower the minimum temperature at which the fluid will flow
or can be poured. Examples of suitable pour point depressants
include alkylated naphthalenes polymethacrylates, polyacrylates,
polyarylamides, condensation products of haloparaffin waxes and
aromatic compounds, vinyl carboxylate polymers, and terpolymers of
dialkylfumarates, vinyl esters of fatty acids and allyl vinyl
ethers. Such additives may be used in amount of 0.0 to 0.5 wt %,
preferably 0 to 0.3 wt %, more preferably 0.001 to 0.1 wt % on an
as-received basis.
Corrosion Inhibitors/Metal Deactivators
[0081] Corrosion inhibitors are used to reduce the degradation of
metallic parts that are in contact with the lubricating oil
composition. Suitable corrosion inhibitors include aryl thiazines,
alkyl substituted dimercapto thiadiazoles thiadiazoles and mixtures
thereof. Such additives may be used in an amount of 0.01 to 5 wt %,
preferably 0.01 to 1.5 wt %, more preferably 0.01 to 0.2 wt %,
still more preferably 0.01 to 0.1 wt % (on an as-received basis)
based on the total weight of the lubricating oil composition.
Seal Compatibility Additives
[0082] Seal compatibility agents help to swell elastomeric seals by
causing a chemical reaction in the fluid or physical change in the
elastomer. Suitable seal compatibility agents for lubricating oils
include organic phosphates, aromatic esters, aromatic hydrocarbons,
esters (butylbenzyl phthalate, for example), and polybutenyl
succinic anhydride and sulfolane-type seal swell agents such as
Lubrizol 730-type seal swell additives. Such additives may be used
in an amount of 0.01 to 3 wt %, preferably 0.01 to 2 wt % on an
as-received basis.
AntiFoam Agents
[0083] 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 percent,
preferably 0.001 to 0.5 wt %, more preferably 0.001 to 0.2 wt %,
still more preferably 0.0001 to 0.15 wt % (on an as-received basis)
based on the total weight of the lubricating oil composition.
Inhibitors and Anti-Rust Additives
[0084] Anti-rust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. One type of anti-rust additive is a
polar compound that wets the metal surface preferentially,
protecting it with a film of oil. Another type of anti-rust
additive absorbs water by incorporating it in a water-in-oil
emulsion so that only the oil touches the surface. Yet another type
of anti-rust additive chemically adheres to the metal to produce a
non-reactive surface. Examples of suitable additives include zinc
dithiophosphates, metal phenolates, basic metal sulfonates, fatty
acids and amines. Such additives may be used in an amount of 0.01
to 5 wt %, preferably 0.01 to 1.5 wt % on an as-received basis.
[0085] In addition to the ZDDP anti-wear additives which are
essential components of the present disclosure, other anti-wear
additives can be present, including zinc dithiocarbamates,
molybdenum dialkyldithiophosphates, molybdenum dithiocarbamates,
other organo molybdenum-nitrogen complexes, sulfurized olefins,
etc.
[0086] The term "organo molybdenum-nitrogen complexes" embraces the
organo molybdenum-nitrogen complexes described in U.S. Pat. No.
4,889,647. The complexes are reaction products of a fatty oil,
dithanolamine and a molybdenum source. Specific chemical structures
have not been assigned to the complexes. U.S. Pat. No. 4,889,647
reports an infrared spectrum for a typical reaction product of that
disclosure; the spectrum identifies an ester carbonyl band at 1740
cm.sup.-1 and an amide carbonyl band at 1620 cm.sup.-1. The fatty
oils are glyceryl esters of higher fatty acids containing at least
12 carbon atoms up to 22 carbon atoms or more. The molybdenum
source is an oxygen-containing compound such as ammonium
molybdates, molybdenum oxides and mixtures.
[0087] Other organo molybdenum complexes which can be used in the
present disclosure are tri-nuclear molybdenum-sulfur compounds
described in EP 1 040 115 and WO 99/31113 and the molybdenum
complexes described in U.S. Pat. No. 4,978,464.
[0088] In the above detailed description, the specific embodiments
of this disclosure have been described in connection with its
preferred embodiments. However, to the extent that the above
description is specific to a particular embodiment or a particular
use of this disclosure, this is intended to be illustrative only
and merely provides a concise description of the exemplary
embodiments. Accordingly, the disclosure is not limited to the
specific embodiments described above, but rather, the disclosure
includes all alternatives, modifications, and equivalents falling
within the true scope of the appended claims. Various modifications
and variations of this disclosure will be obvious to a worker
skilled in the art and it is to be understood that such
modifications and variations are to be included within the purview
of this application and the spirit and scope of the claims.
EXAMPLES
[0089] In Example 1 and Comparative Example A, PCMO (passenger car
motor oil) formulations were prepared containing the base stocks
listed in Table 1. EHC.RTM. 45 is a Group II base stock
commercially available from ExxonMobil. Yubase.RTM. 4 Plus is a
Group III base stock commercially available from SK Lubricants.
Visom.RTM. 6 is a Group III base stock commercially available from
ExxonMobil. All of the base stocks listed in Table 1 are
commercially available. In Table 1, KV means kinematic viscosity,
VI means viscosity index, and CCS means cold cracking simulator
(ASTM D5293).
[0090] Table 2 provides formulation details in weight percent based
on the total weight percent of the formulation. DDI is a
detergent-dispersant-inhibitor package containing detergents,
dispersants, ZDDP, antioxidants, defoamant, pour point depressant,
and friction modifiers. The styrene isoprene block copolymer has a
weight average molecular weight of 150,000 as determined by light
scattering. All of the ingredients are commercially available. The
MB VDA 675301 NBR 34 Seal Test raw data is set forth in Table 3. A
comparison of MB seal performance benefit vs. comparative example
is set forth in Table 4.
TABLE-US-00002 TABLE 1 Typical Properties of Base Stocks EHC .RTM.
Yubase .RTM. Alkylated C.sub.8/C.sub.10 45 4 Plus Visom .RTM. 6
PAO4 PAO 6 Naphthalene TMP Ester API Group II III III IV IV V V
KV40, cSt 22.0 18.2 35.1 18.4 30.9 27.7 19.9 KV100, cSt 4.5 4.2 6.6
4.1 5.9 4.7 4.4 VI 115 134 146 126 140 77 130 Noack, % loss 15 11.9
6.3 12.7 7.4 11.4 4 Pour Point, .degree. C. -18 -18 -21 -54 -54 -41
-53 CCS-30, cP 2870 1155 3752 800 2280 5780 1300 CCS-35, cP 6190
1952 7066 1400 3820 12405 2252
TABLE-US-00003 TABLE 2 PCMO Formulations for Example 1 and
Comparative Example A Comp. Ingredients Ex. A Ex. 1 DDI 11.19 11.29
Styrene Isoprene Block 0.75 0.75 Copolymer Group II Base Stock
43.31 43.21 PAO 6 25 25 PAO 4 12.75 12.75 Alkylated Naphthalene 0 5
C.sub.8/C.sub.10 TMP Ester 7 2 Ash, % 1.0 1.0 Phosphorus, ppm 760
760
TABLE-US-00004 TABLE 3 MB VDA 675301 NBR 34 Seal Test Raw Data for
PCMO Formulations Comp. Method Description Ex. A Ex. 1 Change in
Tensile Strength (%) -18 -14 Elongation at Break (%) -39 -34
Shore-A Hardness (%) -1 -1 Change in Volume (%) 2.1 2.2
TABLE-US-00005 TABLE 4 MB Seal Performance Benefit vs. Comparative
Example % Change vs. Comparative Comp. Example Ex. A Ex. 1
Improvement in Tensile Strength 22 (%) Improvement in Elongation at
13 Break (%)
[0091] Tables 2, 3 and 4 show engine oil formulations where
C.sub.8/C.sub.10 trimethylol propane (TMP) ester has been partially
replaced by alkylated naphthalene. MB NBR 34 seal performance is
improved significantly in the areas of change as measured by
tensile strength (22%) and elongation at break (13%). These
improvements in NBR 34 seal performance as measured by tensile
strength and elongation at break are surprising and unexpected for
the inventive formulations with respect to the prior art
comparative example.
[0092] In Examples 2, 3, 4, 5 and 6 and Comparative Examples B, C,
D, E and F, PCMO formulations were prepared having the ingredients
and the amounts listed in Table 5. The amounts are given in weight
percent based on the total weight percent of the formulation. The
styrene isoprene block copolymer has a weight average molecular
weight of 150,000 as determined by light scattering. The isoprene
star polymer concentrate has a shear stability index (SSI) of 4.
The olefin copolymer viscosity modifier (OCP VM) has a 50 SSI. DDI
is a detergent-dispersant-inhibitor package containing detergents,
dispersants, ZDDP, antioxidants, defoamant, and friction modifier.
All of the ingredients are commercially available. The MB VDA
675301 NBR 34 Seal Test raw data for the formulations is set forth
in Table 6. A comparison of MB seal performance benefit vs.
comparative example is set forth in Table 7.
TABLE-US-00006 TABLE 5 PCMO Formulations for Examples 2, 3, 4, 5
and 6 and Comparative Examples B, C, D, E and F Comp. Comp.
Ingredients Ex. B Ex. 2 Ex. C Ex. 3 Group III Base Stock (4 cSt)
48.40 46.84 52.98 46.86 Group III Base Stock (6 cSt) 17.48 25.96
21.00 27.12 PAO 4 4.10 4.10 Styrene Isoprene Block 0.38 0.38
Copolymer Isoprene Star Polymer 5.20 5.20 4.70 4.70 Concentrate OCP
VM Concentrate 4.50 4.50 DDI 12.52 12.52 11.82 11.82 C8/C10 TMP
Ester 11.92 5.00 Alkylated Naphthalene 5.00 5.00 Ash, % 1.05 1.05
1.05 1.05 Phosphorus, ppm 750 750 750 750 Comp. Comp. Ingredients
Ex. D Ex. 4 Ex. E Ex. 5 Group III Base Stock (4 cSt) 52.73 45.36
49.28 43.34 Group III Base Stock (6 cSt) 18.25 25.62 17.78 23.72
PAO 4 Styrene Isoprene Block Copolymer Isoprene Star Polymer 4.70
4.70 4.70 4.70 Concentrate OCP VM Concentrate 4.50 4.50 4.50 4.50
DDI 11.82 11.82 11.82 11.82 C.sub.8/C.sub.10 TMP Ester 8.00 11.92
Alkylated Naphthalene 8.00 11.92 Ash, % 1.05 1.05 1.05 1.05
Phosphorus, ppm 750 750 750 750 Comp. Ingredients Ex. F Ex. 6 Group
III Base Stock (4 cSt) 46.57 41.86 Group III Base Stock (6 cSt)
17.41 22.12 PAO 4 Styrene Isoprene Block Copolymer Isoprene Star
Polymer 4.70 4.70 Concentrate OCP VM Concentrate 4.50 4.50 DDI
11.82 11.82 C.sub.8/C.sub.10 TMP Ester 15.00 Alkylated Naphthalene
15.00 Ash, % 1.05 1.05 Phosphorus, ppm 750 750
TABLE-US-00007 TABLE 6 MB VDA 675301 NBR 34 Seal Test Raw Data for
PCMO Formulations Comp. Comp. Method Description Ex. B Ex. 2 Ex. C
Ex. 3 Change in Tensile Strength (%) -15 -9.4 -29 -12 Elongation at
Break (%) -32 -25 -46 -32 Shore-A Hardness (%) -1 -1 -0.5 0 Change
in Volume (%) 3.2 2.2 1.95 1.8 Comp. Comp. Method Description Ex. D
Ex. 4 Ex. E Ex. 5 Change in Tensile Strength (%) -23 -10 -21 -7.1
Elongation at Break (%) -40 -23 -42 -26 Shore-A Hardness (%) 0 -1 0
-2 Change in Volume (%) 2.3 2.2 2.8 2.7 Comp. Method Description
Ex. F Ex. 6 Change in Tensile Strength (%) -17 -6.3 Elongation at
Break (%) -38 -22 Shore-A Hardness (%) -2 -2 Change in Volume (%)
3.1 3.1
TABLE-US-00008 TABLE 7 MB Seal Performance Benefit vs. Comparative
Examples % Change vs. Comparative Comp. Comp. Example Ex. B Ex. 2
Ex. C Ex. 3 Improvement in Tensile Strength 37 58 (%) Improvement
in Elongation at 22 31 Break (%) % Change vs. Comparative Comp.
Comp. Example Ex. D Ex. 4 Ex. E Ex. 5 Improvement in Tensile
Strength 57 66 (%) Improvement in Elongation at 43 38 Break (%) %
Change vs. Comparative Comp. Example Ex. F Ex. 6 Improvement in
Tensile Strength 63 (%) Improvement in Elongation at 42 Break
(%)
[0093] Tables 5, 6 and 7 show engine oil formulations where
C.sub.8/C.sub.10 TMP ester has been completely replaced by
alkylated naphthalene. MB NBR 34 seal performance is improved
significantly in the areas of change in tensile strength (37-66%)
and elongation at break (22-43%). Again, these improvements in NBR
34 seal performance as measured by tensile strength and elongation
at break are surprising and unexpected for the inventive
formulations with respect to the prior art comparative example.
PCT and EP Clauses:
[0094] 1. A method of improving nitrile seal compatibility with a
lubricating oil in an engine lubricated with the lubricating oil,
said method comprising using as the lubricating oil a formulated
oil comprising a lubricating oil base stock as a major component
and an alkylated aromatic base stock as a minor component; wherein
nitrile seal compatibility is improved as compared to nitrile seal
compatibility achieved using a lubricating oil containing a minor
component other than the alkylated aromatic base stock.
[0095] 2. The method of clause 1 wherein the lubricating oil base
stock comprises a Group I, II, III, IV or V base oil stock, or
mixtures thereof.
[0096] 3. The method of clauses 1 and 2 wherein the lubricating oil
base stock comprises a poly alpha olefin (PAO) or gas-to-liquid
(GTL) oil base stock.
[0097] 4. The method of clauses 1-3 wherein the lubricating oil
base stock is present in an amount from 80 weight percent to 99
weight percent, based on the total weight of the lubricating
oil.
[0098] 5. The method of clause 1 wherein the alkylated aromatic
base stock comprises an alkylated naphthalene, an alkylated
benzene, or mixtures thereof.
[0099] 6. The method of clauses 1 and 5 wherein the alkylated
aromatic base stock is selected from the group consisting of alkyl
benzenes, alkyl naphthalenes, alkyl diphenyl oxides, alkyl
naphthols, alkyl diphenyl sulfides, alkylated bis-phenol A,
alkylated thiodiphenol, and mixtures thereof.
[0100] 7. The method of clauses 1, 5 and 6 wherein the alkylated
aromatic base stock is mono-alkylated, dialkylated, or
polyalkylated.
[0101] 8. The method of clauses 1 and 5-7 wherein the alkylated
aromatic base stock is an alkyl naphthalene selected from the group
consisting of mono-, di-, tri-, tetra-, or penta-C.sub.3 alkyl
naphthalene, C.sub.4 alkyl naphthalene, C.sub.5 alkylnaphthalene,
C.sub.6 alkyl naphthalene, C.sub.8 alkyl naphthalene, C.sub.10
alkyl naphthalene, C.sub.1-2 alkyl naphthalene, C.sub.1-4 alkyl
naphthalene, C.sub.1-6 alkyl naphthalene, C.sub.1-8 alkyl
naphthalene, C.sub.10-C.sub.14 mixed alkyl naphthalene,
C.sub.6-C.sub.18 mixed alkyl naphthalene, or mono-, di-, tri-,
tetra-, or penta-C.sub.3, C.sub.4, C.sub.5, C.sub.6, C.sub.8,
C.sub.10, C.sub.12, C.sub.14, C.sub.16, C.sub.18 or mixture thereof
alkyl monomethyl, dimethyl, ethyl, diethyl, or methylethyl
naphthalene, and mixtures thereof.
[0102] 9. The method of clause 1 wherein the minor component other
than the alkylated aromatic base stock comprises an ester.
[0103] 10. The method of clauses 1 and 5-8 wherein the alkylated
aromatic base stock is present in an amount from 1 weight percent
to 15 weight percent, based on the total weight of the lubricating
oil.
[0104] 11. The method of clause 1 wherein the alkylated aromatic
base stock is present in an amount sufficient for the lubricating
oil to exhibit at least one of improved tensile strength (%) and
elongation at break (%) as determined by Nitrile-NBR34 (MB VDA
675301 Method).
[0105] 12. The method of clauses 1-11 wherein the lubricating oil
further comprises one or more of a viscosity index improver,
antioxidant, detergent, dispersant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, antifoam agent, inhibitor, anti-wear additive, friction
modifier, and anti-rust additive.
[0106] 13. The method of clauses 1-12 in which the lubricating oil
is a passenger vehicle engine oil.
[0107] 14. A lubricating engine oil comprising a lubricating oil
base stock as a major component and an alkylated aromatic base
stock as a minor component; wherein the alkylated aromatic base
stock is present in an amount sufficient for the lubricating oil to
exhibit improved nitrile seal compatibility as compared to nitrile
seal compatibility achieved using a lubricating oil containing a
minor component other than the alkylated aromatic base stock.
[0108] 15. The lubricating engine oil of clause 14 wherein the
alkylated aromatic base stock is present in an amount sufficient
for the lubricating oil to exhibit at least one of improved tensile
strength (%) and elongation at break (%) as determined by
Nitrile-NBR34 (MB VDA 675301 Method).
[0109] 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.
[0110] 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.
[0111] 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