U.S. patent application number 16/041285 was filed with the patent office on 2019-01-24 for lubricating compositions with enhanced deposit performance.
This patent application is currently assigned to ExxonMobil Research and Engineering Company. The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Charles L. BAKER, JR., Michael L. BLUMENFELD, James David BURRINGTON, Smruti A. DANCE, Douglas E. DECKMAN, Ewan E DELBRIDGE, David Paul PRISTIC.
Application Number | 20190024010 16/041285 |
Document ID | / |
Family ID | 65015826 |
Filed Date | 2019-01-24 |
United States Patent
Application |
20190024010 |
Kind Code |
A1 |
BLUMENFELD; Michael L. ; et
al. |
January 24, 2019 |
LUBRICATING COMPOSITIONS WITH ENHANCED DEPOSIT PERFORMANCE
Abstract
A lubricant composition includes a lubricating base oil, a
controlled release friction modifier, a dispersant, a viscosity
modifier and a cleanliness booster. The controlled release friction
modifier is an ashless, dispersant-stabilized, borated controlled
release friction modifier including an ionic tetrahedral borate
compound including a cation and a tetrahedral borate anion, wherein
the tetrahedral borate anion includes a boron atom having two
bidentate di-oxo ligands of C.sub.18 tartrimide.
Inventors: |
BLUMENFELD; Michael L.;
(Haddonfield, NJ) ; DECKMAN; Douglas E.; (Mullica
Hill, NJ) ; DANCE; Smruti A.; (Robbinsville, NJ)
; BAKER, JR.; Charles L.; (Thornton, PA) ;
BURRINGTON; James David; (Gates Mills, OH) ; PRISTIC;
David Paul; (Spring, TX) ; DELBRIDGE; Ewan E;
(Concord, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Assignee: |
ExxonMobil Research and Engineering
Company
Annandale
NJ
|
Family ID: |
65015826 |
Appl. No.: |
16/041285 |
Filed: |
July 20, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62535527 |
Jul 21, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2030/02 20130101;
C10N 2030/52 20200501; C10M 2219/046 20130101; C10N 2030/06
20130101; C10M 2215/086 20130101; C10M 2207/262 20130101; C10M
2215/28 20130101; C10M 2227/061 20130101; C10M 143/12 20130101;
C10N 2020/04 20130101; C10N 2060/14 20130101; C10M 2205/0285
20130101; C10M 143/06 20130101; C10M 2203/1025 20130101; C10N
2030/04 20130101; C10M 2205/08 20130101; C10M 101/025 20130101;
C10M 169/04 20130101; C10N 2020/02 20130101; C10N 2040/25
20130101 |
International
Class: |
C10M 143/12 20060101
C10M143/12; C10M 143/06 20060101 C10M143/06; C10M 101/02 20060101
C10M101/02 |
Claims
1. A lubricant composition, comprising: a lubricating base oil; a
controlled release friction modifier including: a tetrahedral
borate anion having a boron atom with two bidentate di-oxo ligands
both being a linear C.sub.18-tartrimide; a first dispersant
comprising a conventional ammonium substituted polyisobutenyl
succinimide compound having a polyisobutenyl number average
molecular weight of 750 to 2,500; a second dispersant comprising an
ammonium substituted polyisobutenyl succinimde compound having an
N:CO ratio of 1.8 and a polyisobutylenyl number average molecular
weight of 750 to 2,500; a third dispersant; a viscosity modifier;
and a cleanliness booster.
2. The lubricant composition according to claim 1, wherein the
viscosity modifier comprises a hydrogenated isoprene star
polymer.
3. The lubricant composition according to claim 1, wherein the
cleanliness booster comprises an alkyl phenol ether polymer or
polyisobutylene.
4. The lubricant composition according to claim 1, wherein the
third dispersant is selected from a group consisting of
succinimide, polyolefin amide alkeneamine, ethylene capped
succinimide and borated polyisobutylsuccinimide-polyamine.
5. The lubricant composition according to claim 1, wherein the
lubricating base oil comprises a highly paraffinic base oil.
6. The lubricant composition according to claim 5, wherein the
highly paraffinic base oil includes a polyalphaolefin base oil, a
Group III base oil or a combination of the polyalphaolefin base oil
and the Group III base oil.
7. The lubricant composition according to claim 5, wherein the
lubricating base oil further comprises a Group V base oil.
8. The lubricant composition according to claim 1, further
comprising a detergent.
9. The lubricant composition according to claim 8, wherein the
detergent is selected from a group consisting of highly overbased
calcium salicylate, low base calcium salicylate, overbased
magnesium sulfonate and neutral calcium sulfonate.
10. The lubricant composition according to claim 1, wherein the
lubricating base oil comprises between 75% to 90% of the lubricant
composition.
11. The lubricant composition according to claim 1, wherein the
dispersant comprises between 1% to 15% of the lubricant
composition.
12. The lubricant composition according to claim 1, wherein
viscosity modifier comprises between 1% to 15% of the lubricant
composition.
13. The lubricant composition according to claim 1, wherein the
controlled release friction modifier comprises between 2% to 8% of
the lubricant composition.
14. The lubricant composition according to claim 1, wherein the
cleanliness booster comprises between 0.5% to 3% of the lubricant
composition.
15. The lubricant composition according to claim 1, wherein the
lubricant composition is formulated using a mixture of the
controlled release friction modifier and the cleanliness booster,
combined into a single homogeneous premix.
16. A lubricant composition, comprising: 26-94% highly paraffinic
base oil; 2%-8% controlled release friction modifier including: a
tetrahedral borate anion having a boron atom with two bidentate
di-oxo ligands both being a linear C.sub.18-tartrimide; a first
dispersant comprising a conventional ammonium substituted
polyisobutenyl succinimide compound having a polyisobutenyl number
average molecular weight of 750 to 2,500; a second dispersant
comprising an ammonium substituted polyisobutenyl succinimde
compound having an N:CO ratio of 1.8 and a polyisobutylenyl number
average molecular weight of 750 to 2,500; 1%-15% of a third
dispersant; 1%-15% viscosity modifier; 1%-10% detergent; and
0.5%-3% cleanliness booster.
17. A lubricant composition, comprising: a highly paraffinic
lubricating base oil; an ashless, dispersant-stabilized, borated
controlled release friction modifier including: a tetrahedral
borate anion having a boron atom with two bidentate di-oxo ligands
both being a linear C.sub.18-tartrimide; a first dispersant
comprising a conventional ammonium substituted polyisobutenyl
succinimide compound having a polyisobutenyl number average
molecular weight of 750 to 2,500; a second dispersant comprising an
ammonium substituted polyisobutenyl succinimde compound having an
N:CO ratio of 1.8 and a polyisobutylenyl number average molecular
weight of 750 to 2,500; a third dispersant selected from a group
consisting of succinimide, polyolefin amide alkeneamine, ethylene
capped succinimide and borated polyisobutylsuccinimide-polyamine; a
viscosity modifier comprising a hydrogenated isoprene star polymer;
and a cleanliness booster comprising an alkyl phenol ether polymer
or polyisobutylene.
18. A lubricant composition, consisting of: 10% polyalphaolefin
base oil; 64.21% Group III base oil; 5% alkylated naphthalene
co-baseoil; 4.99% of supporting additives including antioxidants,
detergents, antiwear, antifoam, inorganic friction modifiers and
pour point depressants; 6.4% hydrogenated isoprene star polymer 7;
1% of a cleanliness booster; 0.74% borated PIBSA/PAM dispersant;
3.96% of an ashless, dispersant-stabilized borated friction
modifier Including: a tetrahedral borate anion having a boron atom
with two bidentate di-oxo ligands both being a linear
C.sub.18-tartrimide; a first dispersant comprising a conventional
ammonium substituted polyisobutenyl succinimide compound having a
polyisobutenyl number average molecular weight of 750 to 2,500; a
second dispersant comprising an ammonium substituted polyisobutenyl
succinimde compound having an N:CO ratio of 1.8 and a
polyisobutylenyl number average molecular weight of 750 to 2,500;
and 3.7% of a succinimide dispersant differing from either the
first dispersant and second dispersant.
Description
[0001] This nonprovisional application claims priority to U.S.
Provisional Application No. 62/535,527, which was filed on Jul. 21,
2017, and is herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a lubricant composition, in
particular, a lubricant composition, suitable for use in, for
example, internal combustion engines, which reduces deposit
formation and friction in an engine.
Description of the Background Art
[0003] Engine oils are formulated for the purpose of reducing
friction in the engine, engine cleanliness (e.g., deposit control),
control of wear, corrosion and rust in the engine. To accomplish
this goal, engine oils contain numerous and various additives
including friction modifiers, detergents, dispersants, viscosity
modifiers and antioxidants.
[0004] Of significant concern is the reduction of friction in
engines so as to improve fuel economy necessitating the use of
lower viscosity lubricating base stocks while also meeting the
competing requirements of maintaining sufficiently high lubricating
oil film thickness at high operating temperature to avoid
incidental breakdown of the oil film under boundary conditions
while still maintaining low wear over a wide range of
temperatures.
[0005] Traditionally, fuel economy favors lower viscosity engine
oils and the use of friction modifying additives. Fuel economy,
often measured in operating engine tests, is only one of many
performance needs of modern engine oil. Other performance needs
include, for example, oxidation stability of the lubricant over
time, deposit formation on internal engine surfaces and a variety
of physical and chemical tests needed to ensure the oil will be
suitable in an engine. Because there are many requirements, the
chemistry used to formulate engine oils is complex. Often a
particular additive that can improve one aspect of a lubricant's
performance works against the performance enabled by other
additives.
[0006] Current well known fuel economy additives include various
oil-soluble compounds of molybdenum as well as NOCH (nitrogen,
oxygen-containing chemistries). The highest performing lubricants
usually entail the use of base oils that are highly paraffinic.
Such base oils would include API Group IV polyalphaolefin (PAO)
base oils, API Group III base oils such as gas-to-liquid base oils
and potentially even highly saturated Group II base oils. Such oils
are highly non-polar and, as a result, have a limited amount of
solubility for polar additives. Additionally, the use of highly
paraffinic base oils can increase the amount of unwanted deposit
formation.
[0007] Friction modifiers, which are among the additives used in
lubricant compositions, are used to improve the composition's
ability to reduce friction. Among the friction modifiers that can
be used in a lubricant composition are borated friction modifiers.
Documents disclosing conventional borated friction modifiers
include U.S. Pat. No. 4,522,734A disclosing borated long-chain
(C10-20) epoxides, EP 0036708A1 disclosing borated fatty acid
esters of glycerol, U.S. Pat. No. 5,759,965A disclosing borated
alkoxylated fatty amines, US 2009/0005276A1 disclosing borated
polyalkene succinimides, WO 2007005423A2 disclosing a reaction
product of C8-20 fatty acids with dialkanolamines and boric acid,
CA 1336830C disclosing borated hydroxyl ether amines and U.S. Pat.
No. 4,522,629A disclosing borated phosphonates. While these
documents disclose borated friction modifiers, there still exists a
need for lubricant compositions including borated friction
modifiers, which better facilitate improvements in the necessary
benefits described above.
[0008] Specifically, most fuel economy additives, including the
friction modifiers detailed above, are highly polar and, as such,
are challenged to remain soluble in the lubricating oil. With
limited solubility and availability of the additives, improvements
in fuel economy are similarly limited. In addition, many of the
additives degrade or are consumed in service with the result that
fuel economy is more difficult to maintain for extended times.
Additionally, conventional friction modifiers typically cause
increased deposit formation as they have limited solubility and are
rapidly oxidized in-service.
[0009] Known lubricant compositions for use as motor oils are
described in documents such as U.S. Pat. No. 9,193,934B2, U.S. Pat.
No. 9,163,196B2, US 2014/0045734A1, U.S. Pat. No. 9,175,241B2, US
2012/0283158A1 and US 2014/0107000A1. These documents describe
compositions that have been formulated for clarity and stability.
These documents, however, do not describe compositions that have
been formulated to provide increased fuel economy while also
reducing deposit formation and friction in an engine. Accordingly,
there exists a need for improved lubricant compositions including
additives that highly soluble and mitigate unwanted deposit
formation, thus providing an increased cleanliness.
SUMMARY OF THE INVENTION
[0010] In view of the foregoing and other exemplary problems,
drawbacks, and disadvantages of the conventional methods and
compositions, an exemplary feature of the present invention is to
improve fuel economy by providing a lubricating oil composition
having an increased amount of friction modifier while also
mitigating deposit formation through a combination of additives
that include a synergistic use of dispersant, viscosity modifier
and cleanliness booster.
[0011] In accordance with a first exemplary, non-limiting aspect of
the present invention, a lubricant composition includes a
lubricating base oil, a controlled release friction modifier
(CRFM), a dispersant, a viscosity modifier and a cleanliness
booster.
[0012] In accordance with a second exemplary, non-limiting aspect
of the present invention, a lubricant composition includes 26-94%
highly paraffinic base oil, 2%-8% CRFM, 1%-15% dispersant, 1%-15%
viscosity modifier, 1%-10% detergent and 0.5%-3% cleanliness
booster.
[0013] In accordance with a third exemplary, non-limiting aspect of
the present invention, a lubricant composition includes a highly
paraffinic lubricating base oil, an ashless CRFM including a
dispersant-stabilized, borated CRFM comprising an ionic tetrahedral
borate compound including a tetrahedral borate anion having a boron
atom with two bidentate di-oxo ligands both being a linear
C18-tartrimide, a first dispersant comprising a conventional
ammonium substituted polyisobutenyl succinimide compound having a
polyisobutenyl number average molecular weight of 750 to 2,500, a
second dispersant comprising an ammonium substituted polyisobutenyl
succinimde compound having an N:CO ratio of 1.8 and a
polyisobutylenyl number average molecular weight of 750 to 2,500,
wherein one or more of the first dispersant and the second
dispersant are in cationic form (referred to herein as a
dispersant-stabilized borated CRFM) an additional dispersant
selected from a group consisting of succinimide, polyolefin amide
alkeneamine, ethylene capped succinimide and borated
polyisobutylsuccinimide-polyamine, a viscosity modifier comprising
a hydrogenated isoprene star polymer and a cleanliness booster
comprising an alkyl phenol ether polymer or polyisobutylene.
[0014] In accordance with a fourth exemplary, non-limiting aspect
of the present invention, a lubricant composition consists of, or
is formed only of, 10% polyalphaolefin base oil, 64.21% Group III
base oil, 5% alkylated naphthalene co-baseoil, 4.99% of a package
of supporting additives including antioxidants, detergents,
antiwear, antifoam, inorganic friction modifiers and pour point
depressants, 6.4% hydrogenated isoprene star polymer 7, 1% of a
cleanliness booster, 0.74% borated PIBSA/PAM dispersant, 3.7%
succinimide dispersant and 3.96% of an ashless,
dispersant-stabilized borated CRFM.
[0015] Accordingly, the claimed invention includes a
dispersant-stabilized, borated CRFM that provides a much larger
amount of friction modifier in the lubricating oil composition,
which results in improved overall fuel economy. Additionally, the
CRFM is a low-ash composition, which reduces potential damage from
ash to ash particulate filters.
[0016] Adding the above CRFM to a lubricating oil composition
offers a number of challenges, including CRFM deposit formation.
The composition of the present invention has surprisingly mitigated
the formation of deposits from the CRFM by also including a
combination of additives that include a synergistic use of
dispersant, viscosity modifier and cleanliness booster. Thus, the
present invention provides a lubricating oil composition that not
only improves overall fuel economy but does so while meeting other
performance specifications that require the VW TDi2 (CEC
L-78-99).
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The present invention will become more fully understood from
the detailed description given herein below and the accompanying
drawings which are given by way of illustration only, and thus, do
not limit the present invention, and wherein:
[0018] FIG. 1 is a graph illustrating effects of CRFM on deposit
merits; and
[0019] FIG. 2 is a graph illustrating deposit merits of lubricating
oil compositions according to certain exemplary embodiments of the
present invention.
DETAILED DESCRIPTION
[0020] Aspects of the invention are disclosed in the following
description and related drawings directed to specific embodiments
of the invention. Alternate embodiments may be devised without
departing from the scope of the invention. Additionally, well-known
elements of the invention will not be described in detail or will
be omitted so as not to obscure the relevant details of the
invention.
[0021] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any embodiment described
herein as "exemplary" is not necessarily to be construed as
preferred or advantageous over other embodiments. Likewise, the
term "embodiments of the invention" does not require that all
embodiments of the invention include the discussed feature,
advantage or mode of operation.
[0022] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
embodiments of the invention. As used herein, the singular forms
"a", "an" and "the" are intended to include the plural forms as
well, unless the context clearly indicates otherwise. It will be
further understood that the terms "comprises", "comprising,",
"includes" and/or "including", when used herein, specify the
presence of stated features, integers, steps, operations, elements,
and/or components, but do not preclude the presence or addition of
one or more other features, integers, steps, operations, elements,
components, and/or groups thereof.
[0023] The present invention is directed to a lubricant composition
suitable for use as an engine oil, the usage of which results in
improved fuel economy throughout the time that the composition is
used in an engine while also mitigating deposit formation through a
combination of additives that include a synergistic use of
dispersant, viscosity modifier and cleanliness booster. In some
embodiments, the lubricant composition comprises a CRFM.
Additionally, in some exemplary embodiments, the lubricant
composition further comprises an American Petroleum Institute (API)
Group III base stock, a polyalphaolefin (PAO) base stock, a
dispersant, a viscosity modifier and a cleanliness booster. In some
exemplary embodiments, the lubricant composition further comprises
at least one of, a Group V co-base stock, an inorganic friction
modifier, a dispersant, a detergent, as well as other lubricant
composition additives.
[0024] Basestocks
[0025] In certain exemplary embodiments of the present invention,
the lubricating composition includes API Group III base oils and/or
API Group IV polyalphaolefin (PAO) base oils as base stock. In
certain exemplary embodiments, the lubricant composition also
includes API Group V base oil as a co-base stock.
[0026] A wide range of lubricating base oils is known in the art.
Lubricating base oils 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 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 oil that has been
previously used as feed stock.
[0027] Groups I, II, III, IV and V are broad categories of base oil
stocks developed and defined by the American Petroleum Institute
(API Publication 1509) to create guidelines for lubricant base
oils. Group I base stocks have a viscosity index of between 80 to
less than 120 and contain greater than about 0.03% sulfur and less
than 90% saturates. Group II base stocks have a viscosity index of
between 80 to less than 120, and contain less than or equal to
about 0.03% sulfur and greater than or equal to about 90%
saturates. Group III stocks have a viscosity index greater than or
equal to 120 and contain less than or equal to 0.03% sulfur and
greater than 90% saturates. Group IV includes polyalphaolefins
(PAO). Group V base stock includes base stocks not included in
Groups I-IV. The table below summarizes properties of each of these
five groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I <90 and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV Includes
polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III or IV
[0028] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source; for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful. Natural oils vary also
as to the method used for their production and purification; for
example, their distillation range and whether they are straight run
or cracked, hydrorefined, or solvent extracted.
[0029] 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.
[0030] 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 125, more preferably
greater than 135, still more preferably greater than 140.
[0031] The hydrocarbyl aromatics can be used as base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least about 5% of its weight derived from an aromatic moiety such
as a benzenoid moiety or naphthenoid moiety, or their derivatives.
These hydrocarbyl aromatics include alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and the like. The aromatics can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can also be comprised
of mixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl
groups, cycloalkenyl groups and other related hydrocarbyl groups.
The hydrocarbyl groups can range from about C.sub.6 up to about
C.sub.60 with a range of about C.sub.8 to about C.sub.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 about 5% of the molecule is comprised of an above-type
aromatic moiety. Viscosities at 100.degree. C. of approximately 3
cSt to about 50 cSt are preferred, with viscosities of
approximately 3.4 cSt to about 20 cSt often being more preferred
for the hydrocarbyl aromatic component. Naphthalene or methyl
naphthalene, for example, can be alkylated with olefins such as
octene, decene, dodecene, tetradecene or higher, mixtures of
similar olefins, and the like. Useful concentrations of hydrocarbyl
aromatic in a lubricant oil composition can be about 2% to about
25%, preferably about 4% to about 20%, and more preferably about 4%
to about 15%, depending on the application.
[0032] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, 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.
[0033] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols such as the neopentyl polyols; e.g., neopentyl
glycol, trimethylol ethane, 2 methyl 2 propyl 1,3 propanediol,
trimethylol propane, pentaerythritol and dipentaerythritol with
alkanoic acids containing at least about 4 carbon atoms, preferably
C.sub.5 to C.sub.30 acids such as saturated straight chain fatty
acids including caprylic acid, capric 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.
[0034] 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
about 20 or greater, preferably about 30 or greater and mixtures of
such base stocks and/or base oils.
[0035] Base oils for use in the formulated lubricating oils useful
in the present invention are any of the variety of oils
corresponding to API Group I, Group II, Group III, Group IV, and
Group V oils and mixtures thereof, preferably API Group II, Group
III, Group IV, and Group V oils and mixtures thereof, more
preferably the Group III to Group V base oils due to their
exceptional volatility, stability, viscometric and cleanliness
features. Minor quantities of Group I stock, such as the amount
used to dilute additives for blending into formulated lube oil
products, can be tolerated but should be kept to a minimum, i.e.
amounts only associated with their use as diluent/carrier oil for
additives used on an "as-received" basis. Even in regard to the
Group II stocks, it is preferred that the Group II stock be in the
higher quality range associated with that stock, i.e. a Group II
stock having a viscosity index in the range 100<VI<120.
[0036] In accordance with certain exemplary embodiments of the
present invention, the lubricating oil includes base oils (base
stocks) of 75 wt % to 94 wt % of the total lubricating oil
composition. In accordance with certain exemplary embodiments, the
base oil includes a highly paraffinic base oil, chosen from a Group
III oil or a polyalphaolefin base oil. The highly paraffinic base
oil may include the Group III oil, the polyalphaolefin base oil or
a combination of both. Preferably, the highly paraffinic base oil
makes up 26 wt % to 94 wt %, and even more preferably, 47 wt % to
94 wt % of the total lubricating oil composition by weight.
Furthermore, in certain exemplary embodiments of the invention, the
base oil may also include a Group V base oil. The Group V base oil
is preferably selected from ester and alkylated naphthalene. The
Group V base oil may be present in an amount ranging from 0 wt % to
15 wt % of the total lubricating oil composition and, even more
preferably, in an amount ranging from 0 wt % to 10 wt %. In certain
preferable embodiments, the lubricating oil composition includes 5
wt % of Group V base oil.
[0037] Controlled Release Friction Modifier (CRFM)
[0038] In accordance with certain exemplary aspects of the present
invention, the lubricating composition includes a CRFM. The CRFM is
a dispersant-stabilized, borated CRFM comprising an ionic
tetrahedral borate compound including a tetrahedral borate anion
having a boron atom with two bidentate di-oxo ligands both being a
linear C18-tartrimide, a first dispersant comprising a conventional
ammonium substituted polyisobutenyl succinimide compound having a
polyisobutenyl number average molecular weight of 750 to 2,500, a
second dispersant comprising an ammonium substituted polyisobutenyl
succinimide compound having an N:CO ratio of 1.8 and a
polyisobutylenyl number average molecular weight of 750 to 2,500,
wherein one or more of the first dispersant and the second
dispersant are in cationic form. As used herein, the term
"conventional ammonium substituted polyisobutenyl succinimide,"
refers to an ammonium substituted polyisobutenyl succinimide made
by the chorine-assisted process. Such a process is well known in
the art. One such process includes grafting maleic anhydride to
polyisobutenyl in the presence of chorine followed by reaction with
a poly(amine) to form the imide.
[0039] In accordance with another aspect of the exemplary
embodiment, the CRFM includes a reaction product of a trivalent
boron compound, such as boric acid, with a tartaric acid and a
linear C18 amine under conditions suitable to form an ionic
tetrahedral borate compound. The ionic tetrahedral borate compound
is combined with a first dispersant comprising a conventional
ammonium substituted polyisobutenyl succinimide compound having a
polyisobutenyl number average molecular weight of 750 to 2,500, a
second dispersant comprising an ammonium substituted polyisobutenyl
succinimide compound having an N:CO ratio of 1.8 and a
polyisobutylenyl number average molecular weight of 750 to 2,500,
wherein one or more of the first dispersant and the second
dispersant are converted to a cationic form.
[0040] The above described ionic tetrahedral borate compound can
serve as a friction modifier, in a lubricating composition.
[0041] In one embodiment, the structure of the tetrahedral borate
ion of the tetrahedral borate compound may be represented by the
structure shown in Formula I:
##STR00001##
where R3, R4 form a 5 membered nitrogen-containing heterocyclic
ring substituted with a linear C18 group.
[0042] The cations in Formula I include one or more of a first
ammonium cation including a conventional polyisobutylene
succinimide with number average molecular weight of the
polyisobutylene substituent of at least 750, and can be up to 2500,
and a second ammonium cation is including a polyisobutylene
succinimide with number average molecular weight of the
polyisobutylene substituent of at least 750, and can be up to
2,500, having an N:CO ratio of 1.8. Such succinimides can be
formed, for example, from high vinylidene polyisobutylene and
maleic anhydride.
[0043] Total base number (TBN) is the quantity of acid, expressed
in terms of the equivalent number of milligrams of potassium
hydroxide (meq KOH), that is required to neutralize all basic
constituents present in 1 gram of a sample of the lubricating oil.
The TBN may be determined according to ASTM Standard D2896-11,
"Standard Test Method for Base Number of Petroleum Products by
Potentiometric Perchloric Acid Titration" (2011), ASTM
International, West Conshohocken, Pa., 2003 DOI: 10.1520/D2896-11
(hereinafter, "D2896").
[0044] Specific examples of such amine and ammonium compounds
include polyisobutylene derived succinimide dispersants wherein the
polyisobutylene may be 1000 Mn and the succinimide amine is a
polyethylenepolyamine (Mn 1700 g/mol).
[0045] A useful molar ratio of the tartaric acid, the trivalent
boron compound, and counter ion charge used in forming the
combination and/or reaction product is 2:1:1.
[0046] In an embodiment, the linear C.sub.18 tartrimide compound is
derived from tartaric acid. The tartaric acid used for preparing
the tartrates of the invention can be commercially available, and
it is likely to exist in one or more isomeric forms such as
d-tartaric acid, l-tartaric acid, d,l-tartaric acid, or
mesotartaric acid, often depending on the source (natural) or
method of synthesis (from maleic acid). For example a racemic
mixture of d-tartaric acid and l-tartaric acid is obtained from a
catalyzed oxidation of maleic acid with hydrogen peroxide (with
tungstic acid catalyst). These derivatives can also be prepared
from functional equivalents to the diacid readily apparent to those
skilled in the art, such as esters, acid chlorides, or anhydrides.
The suitable amines will have the formula RNH.sub.2 wherein R
represents a hydrocarbyl group, typically of 6 to 26. Exemplary
primary amines include n-hexylamine, n-octylamine (caprylylamine),
n-decylamine, n-dodecylamine (laurylamine), n-tetradecylamine
(myristylamine), n-pentadecylamine, n-hexadecylamine
(palmitylamine), n-octadecylamine (stearylamine), and
oleylamine.
[0047] Suitable trivalent boron compounds include borate esters of
the general form B(OR).sub.3 where each R is 2-propylheptyl. In an
embodiment, the counter ion is a basic component, such as a
dispersant. The source of the counter ion may be an aminic
dispersant. For solubilization in mineral oil, particular examples
include polyisobutenyl succinimide and polyamine dispersants with a
N:CO ratio of 1.8 and with a TBN of at least 50.
[0048] In an embodiment, the ionic borate compound is the reaction
product of a tartrimide, a borate ester, and at least one basic
component, such as two dispersants, to form a "boro-tartrimide"
friction modifier. The ionic boron compound described herein is
used to improve friction.
[0049] A problem with conventional friction modifiers, as noted
above, is that the friction modifier is not sufficiently soluble,
which leads to an insufficient amount of friction modifier being
available during consumption of the lubricating oil and sludge
(i.e., deposits) may form. The CRFM in accordance with certain
exemplary embodiments of the present invention maintains sufficient
friction modifier at the surface to provide lower friction
lubricating oils while improving overall fuel economy. That is, the
CRFM described herein raises the amount of friction modifier by
using a tetra-valent boron chemistry to complex the friction
modifier. This results in a much larger amount of friction modifier
in the lubricating oil with resulting improvements to fuel economy.
Also, it is know that ash can damage the particulate filter of an
engine. High ash compositions (i.e., compositions with high amounts
of detergent) are not desirable. The present CRFM is preferably a
low ash CRFM.
[0050] In accordance with certain exemplary embodiments of the
present invention, the CRFM is an ashless, dispersant-stabilized,
borated friction modifier. Additionally, the lubricating oil
composition may include an amount of CRFM in a range of 2 wt % to 8
wt %, and more preferably in a range of 3 wt % to 5 wt %, of the
total lubricating oil composition. In certain specific preferred
embodiments, the CRM is provided in an amount of 3.96 wt %.
[0051] Additives
[0052] As noted above, lubricating oils have several competing
concerns (e.g., fuel economy, cleanliness, performance, etc.) that
must be balanced. In order for the lubricating oil to meet all
performance and cleanliness standards while also improving fuel
economy with use of the above CRFM, the lubricating oil must also
include other additives. For example, creating engine oil
formulations incorporating the above CRFM can result in increased
engine deposits from the CRFM. The present inventors have
discovered that the deposits can be mitigated by providing a
combination of additives along with the CRFM. Thus, by using the
CRFM in addition to the combination of additives the lubricating
oil composition according to the exemplary embodiments of the
invention described herein is able to improve fuel economy without
engine sludge (i.e., improved cleanliness). In accordance with
certain exemplary embodiments of the invention, the combination of
additives includes a dispersant, a viscosity modifier and a
cleanliness booster, which together allow the lubricating oil to
meet performance specifications containing the VW TDi2 deposit
test.
[0053] The formulated lubricating oil useful in the present
invention 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).
[0054] Viscosity Modifier
[0055] Viscosity modifiers/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.
[0056] 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 about
10,000 to 1,000,000, more typically about 20,000 to 500,000, and
even more typically between about 50,000 and 200,000.
[0057] 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.
[0058] In accordance with certain preferred embodiments of the
present invention, the viscosity modifier includes hydrogenated
isoprene star polymer 7. Hydrogenated isoprene star polymer 7 is a
hydrogenated isoprene star polymer having a bimodal molecular
weight distribution as defined by dynamic light scattering of a
primary peak at 1004000 g/mol and a secondary peak at 143000 g/mol
The amount of viscosity modifier may range from 1 wt % to 15 wt %,
preferably 1 wt % to 8 wt %, and more preferably 1.8 wt % to 6.4 wt
% based on active ingredient and depending on the specific
viscosity modifier used.
[0059] Detergents
[0060] Detergents can include alkali and alkaline earth metal
phenates, sulfonates, carboxylates, phosphonates, calcium phenates,
calcium sulfonates, magnesium phenates, magnesium sulfonates, other
related components (including borated detergents) and mixtures
thereof. In accordance with certain exemplary embodiments of the
invention, the detergent may be selected from highly overbased
calcium salicylate, low base calcium salicylate, overbased
magnesium sulfonate and neutral calcium sulfonate, and they can be
present either individually or in combination with each other in an
amount in the range of from 1 wt % to 10 wt %, preferably 1 wt % to
5 wt %, and even more preferably from 2.03 wt % to 3.8 wt % (active
ingredient) based on the total weight of the formulated lubricating
oil.
[0061] Dispersant
[0062] 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.
[0063] 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.
[0064] 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;
3,2145,707; 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.
[0065] 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.
[0066] 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 about 1:1 to
about 5:1.
[0067] 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.
[0068] 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.
[0069] 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 about 0.1 to about 5 moles of
boron per mole of dispersant reaction product.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] 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.
[0074] 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.
[0075] Aldehyde reactants useful in the preparation of the high
molecular products useful in this invention 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.
[0076] Exemplary dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinim ides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
about 500 to about 5000 or 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.
[0077] In accordance with certain exemplary embodiments of the
invention, the dispersant may preferably include succinimide,
polyolefin amide alkeneamine, ethylene capped succinimide and
borated polyisobutylsuccinimide-polyamine. The dispersant may be
used in an amount of about 1 wt % to 15 wt %, preferably about 2 wt
% to 12 wt %, more preferably about 4.44 wt % to 9.8 wt % based on
the weight of the total lubricant composition.
[0078] Cleanliness Booster
[0079] The lubricating oil composition further includes a
cleanliness booster. Cleanliness boosters refer to a broad class of
commercially available components used to reduce hard carbonaceous
deposits that form on the piston land and groove surfaces of diesel
engines due to degradation of the base oil and oil additives under
extremely high temperatures. Keeping an engine free of deposits is
highly desirable as the deposits in an engine reduce effective heat
transfer, contribute to friction, and change the highly engineered
clearances of a modern engine which can result is wear. Cleanliness
is difficult to achieve in a modern engine oil formulation due to
limits placed on ash containing componentry (e.g., overbased
detergents) which are used to prevent formation of deposits. These
ash limits are in place to reduce blockage of diesel particulate
filters and limit the amount of an overbased detergent that may be
used in a given engine oil formulation. One method of overcoming
this limit is through the use of ashless cleanliness boosters. Some
of these materials which are commercially available include alkyl
phenol ether polymers, polyisobutylene polymers and ashless
detergent chemistries. These materials are typically used in a
formulation in a range from 0.5-2.0 wt. % and provide a modest but
consistent improvement in cleanliness, in particular in the VW
PV1452 TDi-2 Deposit Test (CEC L-078-99) which is used in multiple
ACEA and OEM claims. This cleanliness boost can range from 1-5
piston deposit merits in the VW PV1452 test depending on depending
on specific chemistry selected, formulation, and treat rate.
According to certain exemplary embodiments of the invention, the
cleanliness booster may include alkyl phenol ether polymer,
polyisobutylene or a combination thereof. The cleanliness booster
may be used in an amount of about 0.5 wt % to 3 wt %, preferably
about 0.5 wt % to 1.5 wt %, more preferably about 1 wt % based on
the weight of the total lubricant composition.
[0080] Other Additives
[0081] As noted above, lubricating oils have several competing
concerns (e.g., fuel economy, cleanliness, performance, etc.) that
must be balanced. In order for the lubricating oil to meet all
performance and cleanliness standards while also improving fuel
economy with use of the above CRFM, the lubricating oil must also
include other additives. In total, the amount of these other
additives may range from 1 wt % to 8 wt % and preferably 2 wt % to
5 wt %.
[0082] The following other additives may be chosen from
conventional friction modifiers, antiwear additives, pour point
depressants, antioxidants, antifoam agents and seal swell
additives.
[0083] Antioxidants
[0084] An anti-oxidant such as a phenolic, aminic, copper compound,
organic sulfide, disulfide or polysulfide can also be present and
is preferably present. Typical antioxidants include phenolic
antioxidants, aminic antioxidants and oil-soluble copper complexes.
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 about 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.
[0085] Generally, therefore, the phenolic anti-oxidant may be
represented by the general formula:
(R).sub.x--Ar--(OH).sub.y
[0086] where Ar is selected from the group consisting of:
##STR00002##
[0087] 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.
[0088] Preferred phenolic anti-oxidant compounds are the hindered
phenolics and phenolic esters which contain a sterically hindered
hydroxyl group, and these include those derivatives of dihydroxy
aryl compounds in which the hydroxyl groups are in the o- or
p-position to each other. Typical phenolic anti-oxidants include
the hindered phenols substituted with C.sub.1+ alkyl groups and the
alkylene coupled derivatives of these hindered phenols. Examples of
phenolic materials of this type 2-t-butyl-4-heptyl phenol;
2-t-butyl-4-octyl phenol; 2-t-butyl-4-dodecyl phenol;
2,6-di-t-butyl-4-heptyl phenol; 2,6-di-t-butyl-4-dodecyl phenol;
2-methyl-6-t-butyl-4-heptyl phenol; 2-methyl-6-t-butyl-4-dodecyl
phenol; 2,6-di-t-butyl-4 methyl phenol; 2,6-di-t-butyl-4-ethyl
phenol; and 2,6-di-t-butyl 4 alkoxy phenol; and
##STR00003##
[0089] Phenolic type anti-oxidants are well known in the
lubricating industry and commercial examples such as Ethanox.RTM.
4710, Irganox.RTM. 1076, Irganox.RTM. L1035, Irganox.RTM. 1010,
Irganox.RTM. L109, Irganox.RTM. L118, Irganox.RTM. L135 and the
like are familiar to those skilled in the art. The above is
presented only by way of exemplification, not limitation on the
type of phenolic anti-oxidants which can be used.
[0090] The phenolic anti-oxidant can be employed in an amount in
the range of about 0.1 to 3 wt %, preferably about 1 to 3 wt %,
more preferably 1.5 to 3 wt % on an active ingredient basis.
[0091] Aromatic amine anti-oxidants include phenyl-.alpha.-naphthyl
amine which is described by the following molecular structure:
##STR00004##
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.
[0092] Other aromatic amine anti-oxidants 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 about 20 carbon
atoms, and preferably contains from about 6 to 12 carbon atoms. The
aliphatic group is a saturated aliphatic group. Preferably, both
R.sup.8 and R.sup.9 are aromatic or substituted aromatic groups,
and the aromatic group may be a fused ring aromatic group such as
naphthyl. Aromatic groups R.sup.8 and R.sup.9 may be joined
together with other groups such as S.
[0093] Typical aromatic amines anti-oxidants have alkyl substituent
groups of at least about 6 carbon atoms. Examples of aliphatic
groups include hexyl, heptyl, octyl, nonyl, and decyl. Generally,
the aliphatic groups will not contain more than about 14 carbon
atoms. The general types of such other additional amine
anti-oxidants 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.
[0094] Another class of anti-oxidant 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.
[0095] Such anti-oxidants may be used individually or as mixtures
of one or more types of anti-oxidants.
[0096] Pour Point Depressants
[0097] 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.
[0098] Anti-Foam Agents
[0099] Anti-foam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical anti-foam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Anti-foam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers.
[0100] The types and quantities of performance additives used in
combination with the instant invention in lubricant compositions
are not limited by the examples shown herein as illustrations.
Examples
[0101] As noted above, creating engine oil compositions including a
CRFM presented certain challenges to the present inventors.
Particularly, the addition of a CRFM to the lubricating oil
composition can result in unmanageable deposit formation from the
CRFM.
[0102] FIG. 1 illustrates a graph of TDi2 piston deposit merits for
initial CRFM formulations. The piston deposit merit is a
cleanliness grade for an engine oil. A merit score of 65 indicates
a passing grade with 70 indicating an exceptionally clean
formulation. As is illustrated in FIG. 1, an initial lubricating
oil (comparative example 2A), which did not include any CRFM, had a
deposit merit score of 65. When CRFM was added to this initial oil,
the deposit merit score drop significantly to 54 (comparative
example 2B) and 50 (comparative example 2C), respectively. Thus,
with merely adding CRFM to an existing engine oil, the deposit
merit score dropped to well below passing. Similarly, another
initial lubricating oil (comparative example 1A), which also did
not include any CRFM, had a deposit score of 68, which is above
passing. When a CRFM was added to this oil (comparative example 1B)
the merit score dropped to approximately 65. In this case, while
the merit score for 1B was still passing, the sole addition of CRFM
to the existing engine oil had a detrimental effect on the deposit
merit score, despite the fact that this example is a high (1.20 wt.
%) sulfated ash formulation.
[0103] Table 1 below illustrates these two examples (Comparative
Example 1A and Comparative Example 1B) which represent early, high
ash formulations of engine oils. Comparative Example 1A did not
include a CRFM. Comparative example 1B, however, did include a
CRFM.
[0104] The comparative examples were tested for cleanliness. The
test used to measure cleanliness is the Volkswagen TDi2 Test. The
experimental result is compared against a reference test to
determine whether the result is a "pass" or a "fail." The
experimental oil must be better than the reference. The VW TDi2
(CEC L-78-99) is an engine dynamometer test used to measure piston
deposits and piston ring sticking of an engine oil. The VW TDi2
uses a Volkswagen 1.9 litre, inline, four-cylinder, turbocharged,
direct injection automotive diesel engine. The 54-hour, two-phase
test cycle alternates between idle (30 minutes with 40.degree. C.
oil sump) and 4150 rpm, full power (150 minutes with 145.degree. C.
oil sump). No oil top-ups are allowed during the test. At the
conclusion of the 54 hours test, the 4 pistons are removed from the
engine and rated for piston cleanliness using a merit scale (higher
result is better) and ring sticking. This same test is used for
later examples discussed throughout the specification.
[0105] In both of the high ash formulations below, the engine oils
exhibited a passing TDi2 deposit merit grade. Though it can be seen
that comparative example 1B had, even though passing, a lower
deposit merit score of 65 as compared with comparative example 1A,
which did not include CRFM and exhibited a score of 68.
TABLE-US-00002 TABLE 1 Comparative 1A 1B Basestocks Group III
Basestock A 37.84 36.36 Group III Basestock B 41 41 Other Includes
Antioxidants, 7.28 6.83 Additives Detergents, Antifoams, Pour Point
Depressant and Antiwear Viscosity Isoprene-based star polymer 6.55
6.55 Modifier Dispersant Borated Dispersant 3 3 Succinimide
Dispersant 4.33 4.33 CRFM Overbased Na Sulfonate Stabilized 1.93
borated friction modifier VW TDi2 Result 68 65 Reference 65 64
Outcome Pass Pass Summary Table CRFM None Detergent Stabilized
Dispersant Succinimide, Borated Succinimide, Borated Viscosity
Modifier Isoprene-Based Star Isoprene-Based Star Polymer Polymer
Cleanliness Booster None None Sulfated Ash 1.20% 1.20%
[0106] As noted above, the compositions in Table 1 are "high ash"
compositions. Ash, also called "sulfated ash," is measured by
standard test ASTM D874. High ash content leads to plugging of
diesel particulate filters which are used as an emission after
treatment device on passenger car diesel vehicles. The diesel
particulate filter removes particulate matter or soot from the
exhaust gas.
[0107] A key North American engine oil specification is the dexos1
specification, which specifically requires sulfated ash to be 1.0%
in a lubricant formulation. Neither of the formulations here could
meet that specification. That is, each of the above comparative
examples 1A and 1B have 1.20% sulfated ash. Ash is typically
delivered by the detergent system, which provides cleanliness, and
the additional ash is capable of cleaning up the deposits that are
caused by friction modifiers (especially high concentrations of
friction modifiers like CRFM). Comparative example 1A is a
formulation without CRFM and the formulation in Comparative example
1B has been balanced for total ash content but contains a CRFM,
which is a detergent stabilized CRFM. Detergent stabilized CRFMs
have some advantages in that they are typically less expensive and
more potent from an active ingredient perspective.
[0108] Table 2 below illustrates comparative examples 2A, 2B and
2C. Comparative example 2A is a low ash (i.e., 0.9 wt % sulfated
ash) composition that does not include a CRFM. The formulation in
comparative example 2A exhibits a passing TDi2 cleanliness score of
65. In each of comparative examples, 2B and 2C, a detergent
stabilized CRFM is added to the low ash formulation. As is
indicated in Table 2 below, once the CRFM is added to the low ash
formulation, the lubricating oil no longer exhibits a passing TDi2
cleanliness score. Indeed, in comparative example 2B the
cleanliness score dropped to 54 and in comparative example 2C the
cleanliness score dropped to 50.
TABLE-US-00003 TABLE 2 Comparative Comparative Comparative 2A 2B 2C
Basestocks polyalphaolefin 33.77 33.76 31.45 Group III Basestock A
10 10 10 Group III Basestock B 30 30 30 Ester Co-basestock 5 5 5
Other Additives Includes Antioxidants, Antiwear, 7.66 6.26 7.66
Detergents, Inorganic Friction Modifier and Antifoam Conventional
Organic Organic FM 0.52 Friction Modifier Dispersant Borated
Dispersant 1.3 1.3 1.3 Succinimide Dispersant 3.25 3.25 polyolefin
amide alkeneamine 4.91 dispersant Viscosity Modifier hydrogenated
isoprene star 8.5 8.5 7.75 polymer 7 CRFM Overbased Na Sulfonate
1.93 1.93 Stabilized borated friction modifier VW TDi2 Result 65 54
50 Reference 65 65 64 Outcome PASS FAIL FAIL Summary Table CRFM
None Detergent Detergent Stabilized Stabilized Dispersant
Succinimide, Succinimide, polyolefin amide Borated Borated
alkeneamine, Borated Viscosity Modifier Styrene Styrene Styrene
Isoprene Isoprene Star Isoprene Star Star Cleanliness Booster None
None None Sulfated Ash 0.9% 0.9% 0.9%
[0109] A difference between comparative examples 2B and 2C is the
dispersant used. In comparative example 2B, the dispersant is a
combination of borated and succinimide dispersants. In comparative
example 2C, a polyolefin amide alkeneamine dispersant was used
instead of the succinimide dispersant. This change in dispersant
resulted in further lowering the VW TDi2 score.
[0110] Thus, the above indicates that stabilized CRFM systems, like
the overbased Na sulfonate stabilized borated friction modifier,
are very detrimental to the cleanliness of low ash formulations
like comparative example 2A. Comparative examples 2B and 2C contain
this ingredient and these formulations resulted in extremely low
TDi2 results. These results would lead one skilled in the art to
conclude that CRFM could not be used in a low ash formulation that
has strong deposit performance.
[0111] Table 3 illustrates both comparative (examples 3A, 3F, and
3G) and inventive examples (3B-3E) for additional low ash
formulations.
TABLE-US-00004 TABLE 3 Comparative Inventive Inventive Inventive
Inventive Comparative Comparative Component 3A 3B 3C 3D 3E 3F 3G
Basestocks Polyalphaolefin 32.1 31.9 30.6 32.0 31.4 30.7 32.9 Group
III Basestock A 10.0 10.0 10.0 10.0 10.0 10.0 29.7 Group III
Basestock B 30.0 30.0 30.0 30.0 30.0 30.0 9.9 Ester Co-Basestock
5.0 5.0 5.0 5.0 5.0 5.0 5.0 Other Includes antioxidants, antifoams,
antiwear, 8.3 7.1 7.1 7.1 7.1 7.1 7.6 Additives inorganic friction
modifiers and detergents Viscosity hydrogenated isoprene star
polymer 6 7.6 Modifier hydrogenated isoperene star polymer 7 8.2
5.6 5.0 4.8 1.8 3.5 CRFM Overbased Na Sulfonate Stabilized 1.9
Borated Friction Modifier Ashless Dispersant-Stabilized Borated 3.5
Friction Modifier (Low Stabilizer) Ashless Dispersant-Stabilized
Borated 4.0 4.0 4.0 4.0 4.0 Friction Modifier (High Stabilizer)
Dispersants Succinimide Dispersant 2.6 6.1 3.2 Borated Dispersant
0.3 1.3 Borated Polyolefin Amide 8.8 Alkeneamine Dispersant
Ethylene Capped Succinimide Dispersant 7.4 Succinimide Dispersant
5.4 Polyolefin Amide Alkeneamine Dispersant 9.8 Cleanliness
Cleanliness Booster 0.0 1.0 1.0 1.0 1.0 1.0 1.0 Booster VW TDI2
Result 59 65 67 65 66 61 59 Reference 64 65 65 65 65 65 64 Outcome
Fail Pass Pass Pass Pass Fail Fail Summary Table Sulfated Ash 0.9%
0.9% 0.9% 0.9% 0.9% 0.9% 0.9%
[0112] Comparative example 3A is a low ash formulation including a
low stabilizer CRFM. Low stabilizer CRFM obtains the majority of
its nitrogen content from the friction modifier portion of the CRFM
system. As illustrated above in Table 3, comparative example 3A
exhibited a failing TDi2 score of 64. In an effort to improve the
TDi2 score, a cleanliness booster was added into comparative
examples 3F and 3G. Example 3F included a dispersant stabilized
CRFM while example 3G included a detergent stabilized CRFM. A
cleanliness booster is known to provide a small benefit on the
order of 1-5 merit point credit in the VW TDi2 test and is as
described above. Cleanliness boosters typically can provide an
incremental but positive benefit, but the effects of cleanliness
boosters saturate above approx. 1.5% in composition and are not
capable of mitigating significant deposit contributors such as
occurs within the broad class of CRFM. Even with the cleanliness
booster, comparative examples 3F and 3G each exhibited a failing
TDi2 score. Thus, from comparative examples 3F and 3G it can be
seen that merely adding a cleanliness booster on its own, whether
the formulation includes a CRFM or not, will not improve deposit
mitigation in the lubricating oil.
[0113] The formulations in inventive examples 3B-3E each include an
ashless, dispersant-stabilized, borated CRFM (high stabilizer).
Dispersant stabilized CRFM use a borated dispersant as the
controlled release agent of the friction modifier. A high
stabilizer CRFM is a sub-class of CRFM whereby <50% of the total
nitrogen content of the CRFM is derived from the tartrimide.
Additionally, the formulations in inventive examples 3B-3E each
also include a cleanliness booster. Finally, the formulations in
inventive examples 3B-3E each also include a hydrogenated isoprene
star polymer 7 viscosity modifier. As can be seen from Table 3
above, each of the inventive examples 3B-3E exhibit a passing TDi2
score in a low ash formulation.
[0114] From Table 3, comparative example 3G shows that even if a
cleanliness booster is added at 1% with the detergent stabilized
CRFM, the formulation still cannot pass the VW TDi2. Furthermore,
comparative example 3A shows that merely changing to a dispersant
stabilized CRFM alone will not provide a passing TDi2 score.
[0115] Instead, the inventive examples 3B-3E in Table 3 provide
evidence for the unexpected results that if one combines the
cleanliness booster and the dispersant stabilized CRFM with a
specific combination of viscosity modifier (hydrogenated isoprene
star polymer 7) and one or more of the group of borated
succinimide, capped succinimide, succinimide or polyalphaolefin
amide alkeneamine dispersant, then one can incorporate a CRFM into
a low ash formulation with passing TDi2 results. This result (from
inventive examples 3B-3E) was, prior to this application, not only
unexpected but also thought to be impossible. That is, conventional
thought, prior to the present application, was that a CRFM could
not be used in a low ash formulation to obtain a passing TDi2
result.
[0116] Table 4 illustrates a preferred example of the lubricating
oil composition. Comparative example 4A is a formulation without
CRFM and has a very strong TDi2 result of 69. Conventionally, a
TDi2 score of 70 is considered an outstanding score. The inventive
example in 4B shows that addition of the dispersant stabilized
CRFM, in combination with the specific formulation of additives
that includes borated succinimide and succinimide dispersants,
hydrogenated isoprene star polymer 7 and 1% of cleanliness booster
in the low ash formulation shows no impact to cleanliness by adding
the CRFM. This is a very surprising and unique result since it is
well known that high concentrations of friction modifiers lead to
deposits. Indeed, as is illustrated in FIG. 2 and Table 4 below,
the formulation in inventive example 4B, with the CRFM added,
exhibits the same TDi2 score of 69 as the comparative exampled 4A,
without the CRFM.
TABLE-US-00005 TABLE 4 Comparative Inventive 4A 4B Basestocks
Polyalphaolefin 10 10 Group III Basestock A 53.6 52.2 Group III
Basestock B 12 12 Aklylated Naphthalene Co-basestock 5 5 Other
Additives Includes antioxidants, antifoams, antiwear, 5.0 5.0
inorganic friction modifiers and detergents Viscosity Modifier
Hydrogenated isoprene star polymer 7 6.2 6.4 Cleanliness Booster
Cleanliness Booster 0.5 1 Dispersant Borated PIBSA/PAM dispersant
1.2 0.7 Succinimide Dispersant 6 3.7 Conventional Organic
Conventional Organic Friction Modifier 0.5 Friction Modifier CRFM
Ashless Dispersant-Stabilized Borated 4.0 Friction Modifier (High
Stabilizer) VW TDI2 Result 69 69 Reference 65 65 Outcome Pass Pass
Summary Table CRFM None Dispersant Stabilized Dispersant
Succinimide Borated Succinimide, Succinimide Viscosity Modifier
hydrogenated isoprene star hydrogenated isoprene star polymer 7
polymer 7 Cleanliness Booster 0.5% 1.0% Sulfated Ash 0.9% 0.9%
[0117] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are to be included within the scope of the following
claims.
* * * * *