U.S. patent application number 13/947513 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 | 20140038864 13/947513 |
Document ID | / |
Family ID | 48901196 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140038864 |
Kind Code |
A1 |
Shough; Anne M. ; et
al. |
February 6, 2014 |
METHOD FOR IMPROVING NITRILE SEAL COMPATIBILITY WITH LUBRICATING
OILS
Abstract
Provided are a lubricating engine oil and a method of improving
nitrile seal compatibility with a lubricating oil in an engine
lubricated with such lubricating oil. The method includes using as
the lubricating oil a formulated oil comprising a lubricating oil
base stock as a major component and one or more additives selected
from the group consisting of (i) a sulfone, sulfolane, or
derivative thereof; (ii) a borate ester, boron amide, or mixtures
thereof; (iii) a sulfurized olefin; (iv) a thiadiazole or
derivative thereof; and (v) a succinic anhydride or derivative
thereof, 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 one or
more additives.
Inventors: |
Shough; Anne M.; (New
Castle, DE) ; Baillargeon; David Joseph; (Cherry
Hill, NJ) ; Jetter; Steven Michael; (East Windsor,
NJ) ; Deckman; Douglas Edward; (Mullica Hill,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shough; Anne M.
Baillargeon; David Joseph
Jetter; Steven Michael
Deckman; Douglas Edward |
New Castle
Cherry Hill
East Windsor
Mullica Hill |
DE
NJ
NJ
NJ |
US
US
US
US |
|
|
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
48901196 |
Appl. No.: |
13/947513 |
Filed: |
July 22, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61679894 |
Aug 6, 2012 |
|
|
|
Current U.S.
Class: |
508/194 ;
508/198; 508/272; 508/302; 508/306; 508/567; 508/568 |
Current CPC
Class: |
C10M 2205/028 20130101;
C10M 135/34 20130101; C10N 2030/36 20200501; C10M 135/04 20130101;
C10M 2219/106 20130101; C10M 2219/04 20130101; C10M 2223/045
20130101; C10M 2227/061 20130101; C10M 2205/02 20130101; C10N
2040/255 20200501; C10M 139/02 20130101; C10M 2207/283 20130101;
C10M 129/68 20130101; C10M 2207/129 20130101; C10M 135/36 20130101;
C10M 2203/1025 20130101; C10M 133/16 20130101; C10M 2219/022
20130101; C10M 129/42 20130101; C10M 135/08 20130101; C10M
2203/1025 20130101; C10N 2020/02 20130101; C10M 2205/028 20130101;
C10N 2020/073 20200501; C10M 2205/028 20130101; C10N 2020/073
20200501; C10M 2203/1025 20130101; C10N 2020/02 20130101 |
Class at
Publication: |
508/194 ;
508/198; 508/302; 508/568; 508/567; 508/272; 508/306 |
International
Class: |
C10M 135/36 20060101
C10M135/36; C10M 135/04 20060101 C10M135/04; C10M 135/34 20060101
C10M135/34; C10M 135/08 20060101 C10M135/08; C10M 129/68 20060101
C10M129/68; C10M 133/16 20060101 C10M133/16 |
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 one or more additives selected from the group consisting of (i)
a sulfone, sulfolane, or derivative thereof; (ii) a borate ester,
boron amide, or mixtures thereof; (iii) a sulfurized olefin; (iv) a
thiadiazole or derivative thereof; and (v) a succinic anhydride or
derivative thereof, 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 one or more additives.
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 (i) the sulfone, sulfolane, or
derivative thereof comprises an alkyl sulfone or alkyl sulfolane;
(ii) the borate ester, boron amide, or mixtures thereof comprises a
mixture of borated alkyl diethanol amides and borated mono
glycerides; (iii) the sulfurized olefin comprises sulfurized
alpha-olefin, sulfurized isomerized alpha-olefin, sulfurized
branched olefin, sulfurized cyclic olefin, or combinations of
these; (iv) the thiadiazole or derivative thereof comprises an
alkyl thiadiazole; and (v) the succinic anhydride or derivative
thereof comprises polyisobutylene (PIB) succinic anhydride.
6. The method of claim 1 wherein the one or more additives are
present in an amount from 0.01 weight percent to 2.0 weight
percent, based on the total weight of the lubricating oil.
7. The method of claim 1 wherein the one or more additives are
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) or
CEC L-39-96 elastomer test using RE-4 nitrile elastomer.
8. The method of claim 1 wherein the lubricating oil further
comprises one or more of a viscosity improver, antioxidant,
detergent, dispersant, pour point depressant, corrosion inhibitor,
metal deactivator, seal compatibility additive, anti-foam agent,
inhibitor, and anti-rust additive.
9. The method of claim 1 in which the lubricating oil is a
passenger vehicle engine oil.
10. A lubricating engine oil comprising a lubricating oil base
stock as a major component and one or more additives selected from
the group consisting of (i) a sulfone, sulfolane, or derivative
thereof; (ii) a borate ester, boron amide, or mixtures thereof;
(iii) a sulfurized olefin; (iv) a thiadiazole or derivative
thereof; and (v) a succinic anhydride or derivative thereof, as a
minor component; wherein the one or more additives are 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 one or more additives.
11. The lubricating engine oil of claim 10 wherein the lubricating
oil base stock comprises a Group I, II, III, IV, or V base oil
stock, or mixtures thereof
12. The lubricating engine oil of claim 10 wherein the lubricating
oil base stock comprises a poly alpha olefin (PAO) or gas-to-liquid
(GTL) oil base stock.
13. The lubricating engine oil of claim 10 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.
14. The lubricating engine oil of claim 10 wherein (i) the sulfone,
sulfolane, or derivative thereof comprises an alkyl sulfone or
alkyl sulfolane; (ii) the borate ester, boron amide, or mixtures
thereof comprises a mixture of borated alkyl diethanol amides and
borated mono glycerides; (iii) the sulfurized olefin comprises
sulfurized alpha-olefin, sulfurized isomerized alpha-olefin,
sulfurized branched olefin, sulfurized cyclic olefin, or
combinations of these; (iv) the thiadiazole or derivative thereof
comprises an alkyl thiadiazole; and (v) the succinic anhydride or
derivative thereof comprises polyisobutylene (PIB) succinic
anhydride.
15. The lubricating engine oil of claim 10 wherein the one or more
additives are present in an amount from 0.01 weight percent to 2.0
weight percent, based on the total weight of the lubricating
oil.
16. The lubricating engine oil of claim 10 wherein the one or more
additives are 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) or CEC L-39-96 elastomer test using RE-4 nitrile
elastomer.
17. The lubricating engine oil of claim 10 wherein the lubricating
oil further comprises one or more of a viscosity improver,
antioxidant, detergent, dispersant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, antifoam agent, inhibitor, and anti-rust additive.
18. The lubricating engine oil of claim 10 in which the lubricating
oil is a passenger vehicle engine oil.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/679,894, 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] Elastomer compatibility is a critical parameter for many
lubrication specifications. Currently, the detailed chemistry of
elastomer compatibility is relatively unknown, thus adjusting
formulations for suitable elastomer compatibility is not
straightforward and can lead to significant costs. In particular,
nitrile-based elastomers tend to be very challenging materials for
lubricant-elastomer compatibility. It is therefore valuable and
essential to identifying lubricant base stocks that are capable of
improving elastomer compatibility. This will allow not only for
improved lubricant formulations but also a greater understanding of
elastomer compatibility chemistry.
[0006] 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.
[0007] The present disclosure also provides many additional
advantages, which shall become apparent as described below.
SUMMARY
[0008] 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.
[0009] This disclosure is directed in part to a method of 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 one or more additives selected
from the group consisting of (i) a sulfone, sulfolane, or
derivative thereof; (ii) a borate ester, boron amide, or mixtures
thereof; (iii) a sulfurized olefin; (iv) a thiadiazole or
derivative thereof; and (v) a succinic anhydride or derivative
thereof, 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 one or
more additives.
[0010] This disclosure relates in part to a lubricating engine oil
comprising a lubricating oil base stock as a major component and
one or more additives selected from the group consisting of (i) a
sulfone, sulfolane, or derivative thereof;
[0011] (ii) a borate ester, boron amide, or mixtures thereof; (iii)
a sulfurized olefin; (iv) a thiadiazole or derivative thereof; and
(v) a succinic anhydride or derivative thereof, as a minor
component. The one or more additives are 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
one or more additives.
[0012] In this disclosure, certain additives including (i) a
sulfone, sulfolane, or derivative thereof; (ii) a borate ester,
boron amide, or mixtures thereof; (iii) a sulfurized olefin; (iv) a
thiadiazole or derivative thereof; and (v) a succinic anhydride or
derivative thereof, have been found to improve nitrile seal
compatibility with lubricating oils when compared to nitrile seal
compatibility achieved using a lubricating oil containing an
additive other than these additives.
[0013] Further objects, features and advantages of the present
disclosure will be understood by reference to the following
drawings and detailed description.
DETAILED DESCRIPTION
[0014] 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.
[0015] 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. The lubricating oils
also include one or more additives selected from the group
consisting of (i) a sulfone, sulfolane, or derivative thereof; (ii)
a borate ester, boron amide, or mixtures thereof; (iii) a
sulfurized olefin; (iv) a thiadiazole or derivative thereof; and
(v) a succinic anhydride or derivative thereof, as a minor
component. The Applicants have unexpectedly and surprisingly
discovered that certain engine oil compositions including PAO or
GTL base stocks with one or more additive indicated in the
preceding sentence have 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
[0016] 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.
[0017] 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.
[0018] API Group I, II, III, IV and V are broad categories of base
oil stocks developed and defined by the American Petroleum
Institute (API Publication 1509; www.API.org) to create guidelines
for lubricant base oils. Group I base stocks 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 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 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
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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 (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.
[0023] 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.
[0024] Other useful API Group V base stocks include alkylated
aromatic base stocks, for example, alkylated naphthalenes and
alkylated benzenes. The alkylated aromatic co-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
co-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 co-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 co-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.
[0025] Illustrative alkylated naphthalenes useful in the present
disclosure are described, for example, in U.S. Patent Publication
No. 2008/0300157.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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 .sup.0.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.
[0030] 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.
[0031] 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
[0032] 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).
[0033] 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.
[0034] 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.
[0035] 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).
[0036] 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.
[0037] 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.
[0038] 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.
Nitrile Seal Compatibility Additives
Sulfones, Sulfolanes, and Derivatives Thereof
[0039] A sulfone, sulfolane, or derivative thereof can be used as a
nitrile seal compatibility additive in the formulations of this
disclosure. A sulfone, sulfolane, or derivative thereof such as a
substituted sulfolane from Lubrizol, Inc., Afton Corp., for example
Lubrizol.RTM. 730, can be used in an effective amount up to 1.0
volume percent, and more preferably from 0.03 to 1.0 percent by
weight of the complete motor oil formula and up to 5 times that
amount in the concentrate. Other sulfone, sulfolane, or derivative
thereof include 3-alkoxysulfolane or the like, in which the alkoxy
group contains at least 4 and preferably 4 to 25 carbon atoms. See
U.S. Pat. Nos. 4,029,587 and 4,116,877, the disclosures of which
are incorporated herein by reference.
[0040] The sulfone and sulfolane compounds and particularly the
substituted sulfones and sulfolanes, are a preferred additives in
the formulations of this disclosure. The sulfone and sulfolane
compounds are also useful as seal swell additives.
[0041] More particularly, nitrile seal compatibility additives
suitable in the present disclosure include 3-isodecoxysulfolane,
and other substituted sulfolanes including those having: i) a
hydrocarbon-based radical having at least 4 carbon atoms such as
aliphatic, (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl or
cycloalkenyl), aromatic, aliphatic- and alicyclic-substituted
aromatic, aromatic-substituted aliphatic and alicyclic radicals,
and the like; examples include butyl, pentyl, hexyl, octyl, decyl,
dodecyl, eicosyl, decenyl, cyclohexyl, phenyl, tolyl, heptylphenyl,
isopropenylphenyl and naphthyl; ii) substituted hydrocarbon
radicals containing non-hydrocarbon substituents which, do not
alter the predominantly hydrocarbon character of the radical such
as halo, nitro, and cyano compounds; and iii) hetero radicals which
are hydrocarbons which contain atoms other than carbon present in a
chain or ring otherwise composed of carbon atoms such as oxygen,
nitrogen and sulfur.
[0042] Other preferred substituted sulfolanes are those in which a
hydrocarbon radical is selected free from acetylenic unsaturation
and which contains 4-100 carbon atoms. Examples (all isomers being
included) are butyl, amyl, hexyl, octyl, decyl, dodecyl, eicosyl,
triacontanyl, butenyl, dodecenyl, phenyl, naphthyl, tolyl,
dodecylphenyl, tetrapropene-alkylated phenyl, phenethyl, cyclohexyl
and methylcyclohexyl. Each of substituted hydrocarbon radicals and
hetero radicals are hydrogen or a lower alkylbased (and usually a
lower alkyl) radical, the word "lower" denoting radicals containing
up to 7 carbon atoms. Examples of lower alkyl radicals (all isomers
being included, but especially the straight chain radicals) are
methyl, ethyl, propyl, butyl and hexyl, with methyl being
preferred.
[0043] The above-described substituted sulfolanes comprise a class
of compounds which may be prepared by the reaction of 3-sulfolene
or a substituted derivative thereof with an organic hydroxy
compound, ordinarily an alcohol. This method for their preparation
is described, for example, in U.S. Pat. No. 2,393,925. The
3-sulfolenes may be prepared by reaction of sulfur dioxide with a
conjugated diene such as butadiene or isoprene.
[0044] Moreover, aliphatic alcohols of 8 to 13 carbon atoms, e.g.,
tridecyl alcohol in combination with an oil-soluble, saturated
hydrocarbyl ester of 10 to 60 carbon atoms and 2 to 3 ester
linkages, e.g., dihexyl phthalate are useful.
[0045] Furthermore, C.sub.1-C.sub.8 alkyl substituted phosphites,
C.sub.1 to C.sub.4 alkyl substituted phenols or aromatic secondary
amine and a dispersant copolymer containing N-vinyl-2-pyrrolidone,
an organophosphite, such as tris(nonylphenyl) phosphite and
mixtures of organic phosphite ester and methylene bisphenol are
useful for oxidation inhibitors for lubricating oils and for
elastomers, including nitrile rubbers.
Borate Esters, Boron Amides, and Mixtures Thereof
[0046] Illustrative borate esters and boron amides useful in this
disclosure include, for example, borate esters and boronate esters
derived from boric acids or boronic acids, amides and glycerides,
and mixtures thereof In addition to providing nitrile seal
compatibility, the borate esters and boronate esters can provide
ashless, almost phosphorus-free and sulfur-free antiwear, extreme
pressure friction modifying additives for lubricating oils and
fuels. Useful borate esters and boron amides are disclosed, for
example, in EP 1 625 193, U.S. Pat. Nos. 4,389,322, 4,406,802,
4,478,732, 4,722,894, 4,975,211, 5,006,272 and 7,291,581, U.S.
Patent Application Publication No. 2003/0234105, the disclosures of
which are incorporated herein by reference.
[0047] Borate esters and boron amides may include borated alkyl
diethanol amides, borated mono glycerides, and Vanlube.RTM. 289
available from R.T. Vanderbilt Company. Preferred borate esters and
boron amides include mixtures of borated alkyl diethanol amides and
borated mono glycerides. The borate esters are also useful as
antiwear additives and dispersants.
Sulfurized Olefins
[0048] The sulfurized olefins useful in the present disclosure can
be prepared by a number of known methods. They are characterized by
the type of olefin used in their production and their final sulfur
content. High molecular weight olefins, i.e., those olefins having
an average molecular weight of 168 to 351 g/mole, are preferred.
Examples of olefins that may be used include alpha-olefins,
isomerized alpha-olefins, branched olefins, cyclic olefins, and
combinations of these.
[0049] Suitable alpha-olefins include any C.sub.4-C.sub.25
alpha-olefins. Alpha-olefins may be isomerized before the
sulfurization reaction or during the sulfurization reaction.
Structural and/or conformational isomers of the alpha olefin that
contain internal double bonds and/or branching may also be used.
For example, isobutylene is the branched olefin counterpart of the
alphaolefin 1-butene.
[0050] Sulfur sources that may be used in the sulfurization
reaction include: elemental sulfur, sulfur monochloride, sulfur
dichloride, sodium sulfide, sodium hydrosulfide, sodium
polysulfide, and mixtures of these added together or at different
stages of the sulfurization process.
[0051] Unsaturated fatty acids and oils, because of their
unsaturation, may also be sulfurized and used in this disclosure.
Examples of fatty acids that may be used include lauroleic acid,
myristoleic acid, palmitoleic acid, oleic acid, elaidic acid,
vaccenic acid, linoleic acid, linolenic acid, gadoleic acid,
arachidonic acid, erucic acid, and mixtures of these. Examples of
oils or fats that may be used include corn oil, cottonseed oil,
grapeseed oil, olive oil, palm oil, peanut oil, rapeseed oil,
safflower seed oil, sesame seed oil, soyabean oil, sunflower seed
oil, and combinations of these. Unsaturated oils include oleyl
oleate, jojoba oil, and the like. Unsaturated fats include lard,
and the like.
[0052] The concentration of sulfurized olefin in the formulated
lubricant oil can vary depending upon the applications, and the
desired level of nitrile seal compatibility required for the
specific formulated oil. An important criteria for selecting the
concentration of the sulfurized olefin used in the formulated oil
is the sulfur concentration of the sulfurized olefin itself The
sulfurized olefin should deliver between 0.05 wt % and 0.30 wt % of
sulfur to the finished lubricant formulation. For example, a
sulfurized olefin containing 20 wt % sulfur content should be used
at levels between 0.25 wt % and 1.5 wt % to deliver between 0.05 wt
% and 0.30 wt % sulfur to the finished oil. A sulfurized olefin
containing 10 wt % sulfur content should be used between 0.5 wt %
and 3.0 wt % to deliver between 0.05 wt % and 0.30 wt % sulfur to
the finished oil.
[0053] Examples of commercial sulfurized olefins which may be used
in the present disclosure include Hitec.RTM. 7084 which contains
approximately 20 wt % sulfur content, Hitec.RTM. 7188 which
contains approximately 12 wt % sulfur content, Hitec.RTM. 312 which
contains approximately 47.5 wt % sulfur content, and Hitec.RTM. 313
which contains approximately 47.5 wt % sulfur content, all from
Afton Corporation, and Additin.RTM. RC 2540-A which contains
approximately 38 wt % sulfur content, from Rhein Chemie
Corporation. Commercially available sulfurized fatty oils, or
mixtures of sulfurized fatty oils and olefins, that may be used in
the present disclosure include Additin.RTM. R 4410 which contains
approximately 9.5 wt % sulfur content, Additin.RTM. R 4412-F which
contains approximately 12.5 wt % sulfur content, Additin.RTM. R
4417 which contains approximately 17.5 wt % sulfur content,
Additin.RTM. RC 2515 which contains approximately 15 wt % sulfur
content, Additin.RTM. RC 2526 which contains approximately 26 wt %
sulfur content, Additin.RTM. RC 2810-A which contains approximately
10 wt % sulfur content, Additin.RTM. RC 2814-A which contains
approximately 14 wt % sulfur content, and Additin.RTM. RC 2818-A
which contains approximately 16 wt % sulfur content, all from Rhein
Chemie Corporation. It is preferred that the sulfurized olefin
and/or fatty oil be a liquid of low corrosivity and low active
sulfur content as determined by ASTM D1662.
[0054] Sulfurized olefins, which may also be employed in the
present disclosure, are typically prepared by the reaction of a
C.sub.3-C.sub.6 olefin, including sulfurized isobutylene, or a
low-molecular-weight polyolefin derived therefrom with a
sulfur-containing compound such as sulfur, sulfur monochloride,
and/or sulfur dichloride. Sulfurized olefins are also useful as
antioxidants.
Thiadiazoles
[0055] The thiadiazole component of the present additive
composition is a non-polycarboxylate moiety-containing thiadiazole.
Preferably, the thiadiazole comprises at least one of
2,5-dimercapto-1,3,4-thiadiazole;
2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazoles;
2-mercapto-5-hydrocarbyl-dithio-1,3,4-thiadiazoles;
2,5-bis(hydrocarbylthio and
2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazoles. The more preferred
compounds are the 1,3,4-thiadiazoles, especially the
2-hydrocarbyidithio-5-mercapto-1,3,4-dithiadiazoles and the
2,5-bis(hydrocarbyidithio)-1,3,4-thiadiazoles, a number of which
are available as articles of commerce. Most preferably, a
non-polycarboxylate-containing thiadiazole containing 4.0 wt %
2,5-dimercapto-1,3,4-thiadiazole, which may be either Afton
Corporation's Hitec.RTM. 4313 or Lubrizol Corporation's
Lubrizol.RTM. 5955A, is used. Hitec.RTM. 4313 may be obtained from
Afton Corporation, Richmond, Va. and Lubrizol.RTM. 5955A may be
obtained from Lubrizol Corporation, Wycliiffe, Ohio. Thiadiazoles
are also useful as antioxidants and sulfur scavengers.
Succinic Anhydrides
[0056] The succinic anhydride component of the present gear oil
additive composition is an alkyl or alkenyl succinic anhydride,
wherein the alkyl or alkenyl group has a number average molecular
weight of 160 to 700. Preferably, the succinic anhydride is an
alkenyl succinic anhydride. Preferred alkenyl succinic anhydrides
include tetrapropenyl succinic anhydride and polyisobutenyl
succinic anhydride. When the alkenyl succinic anhydride is a
polyisobutenyl succinic anhydride, the polyisobutenyl group will
preferably have a molecular weight of 250 to 700, more preferably
450 to 650, and most preferably 500 to 600. A particularly
preferred polyisobutenyl group will have a molecular weight of 550.
If polyisobutenyl succinic anhydride (PIBSA) is used, then the
PIBSA can be prepared by a number of methods. One example of
preparing PIBSA by a thermal reaction is disclosed in U.S. Pat. No.
6,156,850. Other methods of PIBSA preparation include using a
chlorinated polyisobutene as disclosed in U.S. Pat. No. 4,234,435.
The succinic anhydrides are also useful as dispersants.
[0057] The nitrile seal compatibility additives are typically used
in an amount from 0.01 wt % to 2 wt %, preferably 0.025 wt % to 1.5
wt %, and more preferably 0.5 wt % to 1.25 wt %, depending on the
particular formulation.
[0058] The nitrile seal compatibility additive 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 nitrile seal compatibility additive, preferably
improved change in tensile strength (%) and elongation at break (%)
as determined by Nitrile-NBR34 (MB VDA 675301 Method).
Other Additives
[0059] 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).
[0060] 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
[0061] 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.
[0062] 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.
[0063] 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.
[0064] 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
[0065] Typical antioxidant include phenolic antioxidants, aminic
antioxidants and oil-soluble copper complexes.
[0066] 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.
[0067] Generally, therefore, the phenolic anti-oxidant may be
represented by the general formula:
(R).sub.x--Ar--(OH).sub.y
where Ar is selected from the group consisting of:
##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 0.
[0068] 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##
[0069] 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.
[0070] 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.
[0071] Aromatic amine antioxidants include phenyl-a-naphthyl amine
which is described by the following molecular structure:
##STR00003##
wherein R.sup.z is hydrogen or a C.sub.1 to C.sub.14 linear or
C.sub.3 to C.sub.14 branched alkyl group, preferably C.sub.1 to
C.sub.10 linear or C.sub.3 to C.sub.10 branched alkyl group, more
preferably linear or branched C.sub.6 to C.sub.8 and n is an
integer ranging from 1 to 5 preferably 1. A particular example is
Irganox L06.
[0072] 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.19 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.
[0073] Typical aromatic amines anti-oxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 14 carbon atoms. The
general types of such other additional amine antioxidants which may
be present include diphenylamines, phenothiazines, imidodibenzyls
and diphenyl phenylene diamines. Mixtures of two or more of such
other additional aromatic amines may also be present. Polymeric
amine antioxidants can also be used.
[0074] 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.
[0075] 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
[0076] 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.
[0077] 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.
[0078] 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
[0079] 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.
[0080] 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, and/or phosphorus. Typical hydrocarbon chains
contain 50 to 400 carbon atoms.
[0081] 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.
[0082] 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.
[0083] 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.
[0084] 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.
[0085] 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
[0086] 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.
[0087] 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.
[0088] 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.
[0089] 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.
[0090] 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.
[0091] 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.1H, 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.
[0092] 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.
[0093] 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
[0094] 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
[0095] Corrosion inhibitors are used to reduce the degradation of
metallic parts that are in contact with the lubricating oil
composition. Suitable corrosion inhibitors include aryl thiazines,
alkyl substituted dimercapto thiodiazoles thiadiazoles and mixtures
thereof Such additives may be used in an amount of 0.01 to 5 wt %,
preferably 0.01 to 1.5 wt %, more preferably 0.01 to 0.2 wt %,
still more preferably 0.01 to 0.1 wt % (on an as-received basis)
based on the total weight of the lubricating oil composition.
Seal Compatibility Additives
[0096] 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
[0097] 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 Antirust Additives
[0098] 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.
[0099] 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.
[0100] 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.
[0101] 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.
[0102] 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
[0103] PCMO (passenger car motor oil) formulations (1.1% ash) were
prepared having the ingredients and the amounts listed in Table 1.
The amounts are given 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, and friction modifiers. The isoprene star copolymer
concentrate has a shear stability index (SSI) of 4. The Group III
base stock has a viscosity of 4 cSt and a viscosity index of 133.
The second Group III base stock has a viscosity of 6 cSt and a
viscosity index of 146. C.sub.8/C.sub.10 TMP ester is a polyol
ester API Group V base stock with a KV at 100.degree. C. of 4.4
cSt. The olefin copolymer viscosity modifier (OCP VM) has a 50 SSI.
Lubrizol.RTM. 730 is an alkyl sulfone and sulfolane available from
Lubrizol Corporation. Vanlube.RTM. 289 is a mixture of borated
alkyl diethanol amides and borated mono glycerides available from
R.T. Vanderbilt Company. Hitec.RTM. 7188 is a sulfurized olefin
available from Afton Corporation. Hitec.RTM. 4313 is a thiadiazole
derivative available from Afton Corporation. All of the ingredients
are commercially available. The MB Seal Test raw data for PCMO
formulations (1.1% ash) is set forth in Table 2. A comparison of MB
seal performance benefit vs. comparative example is set forth in
Table 3. The sulfated ash (%) was determined by D874 test method.
The data set forth in Tables 2 and 3 was generated by the
Nitrile-NBR34 (MB VDA 675301 Method).
TABLE-US-00002 TABLE 1 PCMO Formulations (1.1% Ash) Comp.
Ingredients Ex. A Ex. 1 Ex. 2 Group III Base Stock (4 cSt) 52.98
52.63 52.76 C.sub.8/C.sub.10 TMP Ester 5.00 5.00 5.00 Group III
Base Stock (6 cSt) 21.00 20.85 20.92 Isoprene Star Polymer 4.70
4.70 4.70 Concentrate OCP VM Concentrate 4.50 4.50 4.50 DDI 11.82
11.82 11.82 Lubrizol .RTM. 730 0.50 Vanlube .RTM. 289 0.30 Hitec
.RTM. 7188 Hitec .RTM. 4313 PIB Succinic Anhydride Ingredients Ex.
3 Ex. 4 Ex. 5 Group III Base Stock (4 cSt) 52.88 52.92 52.63
C.sub.8/C.sub.10 TMP Ester 5.00 5.00 5.00 Group III Base Stock (6
cSt) 21.00 21.01 20.85 Isoprene Star Polymer 4.70 4.70 4.70
Concentrate OCP VM Concentrate 4.50 4.50 4.50 DDI 11.82 11.82 11.82
Lubrizol .RTM. 730 Vanlube .RTM. 289 Hitec .RTM. 7188 0.10 Hitec
.RTM. 4313 0.05 PIB Succinic Anhydride 0.50
TABLE-US-00003 TABLE 2 MB Seal Test Raw Data for PCMO Formulations
(1.1% Ash) Comp. Method Description Ex. A Ex. 1 Ex. 2 Change in
Tensile Strength (%) -29 -16 -16 Elongation at Break (%) -46 -36
-31 Shore-A Hardness (%) -0.5 -2 0 Change in Volume (%) 2 3.7 2.2
Method Description Ex. 3 Ex. 4 Ex. 5 Change in Tensile Strength (%)
-14 -4.8 -15 Elongation at Break (%) -33 -25 -40 Shore-A Hardness
(%) -1 -1 0 Change in Volume (%) 1.9 1.9 2
TABLE-US-00004 TABLE 3 MB Seal Performance Benefit vs. Comparative
Example for PCMO Formulations (1.1% Ash) % Change vs. Comparative
Comp. Example Ex. A Ex. 1 Ex. 2 Improvement in Tensile Strength 44
44 (%) Improvement in Elongation at 22 33 Break (%) % Change vs.
Comparative Example Ex. 3 Ex. 4 Ex. 5 Improvement in Tensile
Strength 51 83 48 (%) Improvement in Elongation at 29 46 14 Break
(%)
[0104] Tables 1, 2 and 3 show engine oil formulations where a 1.1%
ash reference formulation is treated with different additives at
relatively low concentrations. Different additive chemistries are
shown which provide a significant improvement in MB NBR 34 nitrile
seal performance in the areas of change in tensile strength
(44-83%) and elongation at break (14-46%). 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.
[0105] PCMO formulations (0.8% ash) were prepared having the
ingredients and the amounts listed in Table 4. The amounts are
given 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 isoprene star
copolymer concentrate has a shear stability index (SSI) of 4. The
Group III base stock has a viscosity of 4 cSt and a viscosity index
of 133. The second Group III base stock has a viscosity of 6 cSt
and a viscosity index of 146. C.sub.8/C.sub.10 TMP ester is a
polyol ester API Group V base stock with a KV at 100.degree. C. of
4.4 cSt. The olefin copolymer viscosity modifier (OCP VM) has a 50
SSI. Vanlube.RTM. 289 is a mixture of borated alkyl diethanol
amides and borated mono glycerides available from R.T. Vanderbilt
Company. Hitec.RTM. 7188 is a sulfurized olefin available from
Afton Corporation. All of the ingredients are commercially
available. The MB Seal Test raw data for PCMO formulations (0.8%
ash) is set forth in Table 5. A comparison of MB seal performance
benefit vs. comparative example is set forth in Table 6. The
sulfated ash (%) was determined by D874 test method. The data set
forth in Tables 5 and 6 was generated by the Nitrile-NBR34 (MB VDA
675301 Method).
TABLE-US-00005 TABLE 4 PCMO Formulations (0.8% Ash) Comp.
Ingredients Ex. B Ex. 6 Ex. 7 Ex. 8 Group III Base Stock (4 cSt)
54.38 53.58 53.38 53.78 C.sub.8/C.sub.10 TMP Ester 5 5 5 5 Group
III Base Stock (6 cSt) 21 21 21 21 Isoprene Star Polymer 6.5 6.6
6.6 6.6 Concentrate OCP VM Concentrate 2.3 2.35 2.35 2.35 DDI 10.82
11.47 11.67 11.27 Vanlube .RTM. 289 0.30 0.50 Hitec .RTM. 7188
0.10
TABLE-US-00006 TABLE 5 MB Seal Test Raw Data for PCMO Formulations
(0.8% Ash) Comp. Method Description Ex. B Ex. 6 Ex. 7 Ex. 8 Change
in Tensile Strength (%) -30 -16 -14 -12 Elongation at Break (%) -48
-41 -33 -37 Shore-A Hardness (%) -1 -2 -2 -1 Change in Volume (%)
2.1 2.3 2.5 2
TABLE-US-00007 TABLE 6 MB Seal Performance Benefit vs. Comparative
Example for PCMO Formulations (0.8% Ash) % Change vs. Comparative
Comp. Example Ex. B Ex. 6 Ex. 7 Ex. 8 Improvement in Tensile
Strength 47 53 60 (%) Improvement in Elongation at 15 31 23 Break
(%)
[0106] Tables 4, 5 and 6 show engine formulations where a 0.8% ash
reference formulation is treated with different additives at
relatively low concentrations. Different additive chemistries are
shown which provide a significant improvement in MB nitrile seal
performance in the areas of change in tensile strength (47-60%) and
elongation at break (15-23%). 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.
[0107] PCMO formulations (1.4% ash) were prepared having the
ingredients and the amounts listed in Table 7. The amounts are
given 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,
and friction modifier. The isoprene star copolymer concentrate has
a shear stability index (SSI) of 4. The Group III base stock has a
viscosity of 4 cSt and a viscosity index of 133. The Group IV base
stock has a viscosity of 5.8 cSt at 100.degree. C. and a viscosity
index of 137. C.sub.8/C.sub.10 TMP ester is polyol ester API Group
V base stock with a KV at 100.degree. C. of 4.4 cSt. Hitec.RTM.
4313 is a thiadiazole derivative available from Afton Corporation.
All of the ingredients are commercially available. The ACEA RE-4
Seal Test raw data for PCMO formulations (1.4% ash) is set forth in
Table 8. A comparison of ACEA RE-4 seal performance benefit vs.
comparative example is set forth in Table 9. The sulfated ash (%)
was determined by D874 test method. The data set forth in Tables 8
and 9 was generated by the CEC L-39-96 elastomer test using the
RE-4 nitrile elastomer.
TABLE-US-00008 TABLE 7 PCMO Formulations (1.4% Ash) Comp.
Ingredients Ex. C Ex. 9 Group III Base Stock (4 cSt) 30 30
C.sub.8/C.sub.10 TMP Ester 10 10 Group IV Base Stock 36.72 36.62
Alkylated Naphthalene 0.75 0.75 Isoprene Star Polymer 4 4
Concentrate DDI 18.525 18.525 Hitec .RTM. 4313 0.10
TABLE-US-00009 TABLE 8 ACEA RE-4 Nitrile Seal Test Raw Data for
PCMO Formulations (1.4% Ash) Comp. Method Description Ex. C Ex. 9
Change in Tensile Strength (%) -12 0.4 Elongation at Break (%) -38
-21 Shore-A Hardness (%) -2 -2 Change in Volume (%) 3.4 3.6
TABLE-US-00010 TABLE 9 ACEA RE-4 Nitrile Seal Performance Benefit
vs. Comparative Example for PCMO Formulations (1.4% Ash) % Change
vs. Comparative Comp. Example Ex. C Ex. 9 Improvement in Tensile
Strength 103 (%) Improvement in Elongation at 45 Break (%)
TABLE-US-00011 TABLE 10 MB Nitrile Seal Test Raw Data for PCMO
Formulations (1.4% Ash) Comp. Method Description Ex. C Ex. 9 Change
in Tensile Strength (%) -11 -0.4 Elongation at Break (%) -30 -19
Shore-A Hardness (%) -3 -4 Change in Volume (%) 4.1 4.2
TABLE-US-00012 TABLE 11 MB Nitrile Seal Performance Benefit vs.
Comparative Example for PCMO Formulations (1.4% Ash) % Change vs.
Comparative Comp. Example Ex. C Ex. 9 Improvement in Tensile
Strength 96 (%) Improvement in Elongation at 37 Break (%)
[0108] Tables 7-11 show engine formulations where a 1.4% ash
reference formulation is treated with a thiadiazole additive at a
relatively low concentration (0.1%). Table 9 shows a significant
improvement in MB nitrile seal performance in the areas of change
in tensile strength (103%) and elongation at break (45%). Table 11
shows a significant improvement in MB NBR 34 nitrile seal
performance in the areas of change in tensile strength (96%) and
elongation at break (37%). 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:
[0109] 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 one or more additives selected from the group consisting of (i)
a sulfone, sulfolane, or derivative thereof; (ii) a borate ester,
boron amide, or mixtures thereof; (iii) a sulfurized olefin; (iv) a
thiadiazole or derivative thereof; and (v) a succinic anhydride or
derivative thereof, 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 one or more additives.
[0110] 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
[0111] 3. The method of clauses 1 and 2 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.
[0112] 4. The method of clauses 1-3 wherein (i) the sulfone,
sulfolane, or derivative thereof comprises an alkyl sulfone or
alkyl sulfolane; (ii) the borate ester, boron amide, or mixtures
thereof comprises a mixture of borated alkyl diethanol amides and
borated mono glycerides; (iii) the sulfurized olefin comprises
sulfurized alpha-olefin, sulfurized isomerized alpha-olefin,
sulfurized branched olefin, sulfurized cyclic olefin, or
combinations of these; (iv) the thiadiazole or derivative thereof
comprises an alkyl thiadiazole; and (v) the succinic anhydride or
derivative thereof comprises polyisobutylene (PIB) succinic
anhydride.
[0113] 5. The method of clauses 1-4 wherein the one or more
additives are present in an amount from 0.01 weight percent to 2.0
weight percent, based on the total weight of the lubricating
oil.
[0114] 6. The method of clauses 1-5 wherein the one or more
additives are 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) or CEC L-39-96 elastomer test using RE-4 nitrile
elastomer.
[0115] 7. A lubricating engine oil comprising a lubricating oil
base stock as a major component and one or more additives selected
from the group consisting of (i) a sulfone, sulfolane, or
derivative thereof; (ii) a borate ester, boron amide, or mixtures
thereof; (iii) a sulfurized olefin; (iv) a thiadiazole or
derivative thereof; and (v) a succinic anhydride or derivative
thereof, as a minor component; wherein the one or more additives
are 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 one or more additives.
[0116] 8. The lubricating engine oil of clause 7 wherein the
lubricating oil base stock comprises a Group I, II, III, IV, or V
base oil stock, or mixtures thereof
[0117] 9. The lubricating engine oil of clauses 7 and 8 wherein the
lubricating oil base stock comprises a poly alpha olefin (PAO) or
gas-to-liquid (GTL) oil base stock.
[0118] 10. The lubricating engine oil of clauses 7-9 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.
[0119] 11. The lubricating engine oil of clauses 7-10 wherein (i)
the sulfone, sulfolane, or derivative thereof comprises an alkyl
sulfone or alkyl sulfolane; (ii) the borate ester, boron amide, or
mixtures thereof comprises a mixture of borated alkyl diethanol
amides and borated mono glycerides; (iii) the sulfurized olefin
comprises sulfurized alpha-olefin, sulfurized isomerized
alpha-olefin, sulfurized branched olefin, sulfurized cyclic olefin,
or combinations of these; (iv) the thiadiazole or derivative
thereof comprises an alkyl thiadiazole; and (v) the succinic
anhydride or derivative thereof comprises polyisobutylene (PIB)
succinic anhydride.
[0120] 12. The lubricating engine oil of clauses 7-11 wherein the
one or more additives are present in an amount from 0.01 weight
percent to 2.0 weight percent, based on the total weight of the
lubricating oil.
[0121] 13. The lubricating engine oil of clauses 7-12 wherein the
one or more additives are 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) or CEC L-39-96 elastomer test
using RE-4 nitrile elastomer.
[0122] 14. The lubricating engine oil of clauses 7-13 wherein the
lubricating oil further comprises one or more of a viscosity
improver, antioxidant, detergent, dispersant, pour point
depressant, corrosion inhibitor, metal deactivator, seal
compatibility additive, anti-foam agent, inhibitor, and anti-rust
additive.
[0123] 15. The lubricating engine oil of clauses 7-14 in which the
lubricating oil is a passenger vehicle engine oil.
[0124] 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.
[0125] 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.
[0126] 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