U.S. patent application number 16/041300 was filed with the patent office on 2019-01-24 for lubricant composition promoting sustained fuel economy.
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.
Application Number | 20190024015 16/041300 |
Document ID | / |
Family ID | 65015299 |
Filed Date | 2019-01-24 |
United States Patent
Application |
20190024015 |
Kind Code |
A1 |
BLUMENFELD; Michael L. ; et
al. |
January 24, 2019 |
LUBRICANT COMPOSITION PROMOTING SUSTAINED FUEL ECONOMY
Abstract
A lubricant composition includes a controlled release friction
modifier (CRFM), a highly paraffinic base stock, a dispersant and a
detergent. The CRFM includes an ionic tetrahedral borate compound
including a cation and a tetrahedral borate anion, wherein the
tetrahedral borate anion comprises a boron atom having two
bidentate di-oxo ligands of C.sub.18 tartrimide. The lubricant
composition can also include at least one of a Group V co-base
stock, an inorganic friction modifier, a viscosity modifier, and a
cleanliness booster.
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) ;
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: |
65015299 |
Appl. No.: |
16/041300 |
Filed: |
July 20, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62535509 |
Jul 21, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 2205/0206 20130101;
C10M 107/02 20130101; C10N 2030/04 20130101; C10M 2219/046
20130101; C10M 161/00 20130101; C10M 169/044 20130101; C10M 105/32
20130101; C10N 2020/04 20130101; C10M 2215/30 20130101; C10M 105/04
20130101; C10M 2203/1025 20130101; C10M 139/00 20130101; C10M
143/14 20130101; C10M 2203/065 20130101; C10N 2040/255 20200501;
C10M 2205/22 20130101; C10M 2215/28 20130101; C10M 2207/2805
20130101; C10M 105/06 20130101; C10M 133/44 20130101; C10N 2030/54
20200501; C10M 135/10 20130101; C10M 2217/046 20130101; C10M 111/04
20130101; C10M 2219/044 20130101; C10N 2030/02 20130101; C10N
2030/06 20130101; C10M 2207/262 20130101; C10M 2205/08 20130101;
C10M 2227/062 20130101; C10M 2205/024 20130101; C10M 2207/144
20130101; C10M 129/54 20130101; C10M 149/22 20130101; C10M 2205/028
20130101; C10M 2227/061 20130101; C10M 2203/1025 20130101; C10N
2020/02 20130101; C10M 2207/262 20130101; C10N 2010/04 20130101;
C10M 2219/046 20130101; C10N 2010/04 20130101; C10M 2205/024
20130101; C10N 2020/073 20200501; C10N 2060/02 20130101; C10M
2215/28 20130101; C10N 2060/14 20130101; C10M 2207/144 20130101;
C10N 2010/04 20130101; C10M 2219/044 20130101; C10N 2010/04
20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101; C10M
2207/262 20130101; C10N 2010/04 20130101; C10M 2219/046 20130101;
C10N 2010/04 20130101; C10M 2207/144 20130101; C10N 2010/04
20130101; C10M 2219/044 20130101; C10N 2010/04 20130101; C10M
2205/024 20130101; C10N 2020/073 20200501; C10N 2060/02 20130101;
C10M 2215/28 20130101; C10N 2060/14 20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04; C10M 105/04 20060101 C10M105/04; C10M 107/02 20060101
C10M107/02; C10M 105/32 20060101 C10M105/32; C10M 105/06 20060101
C10M105/06; C10M 111/04 20060101 C10M111/04; C10M 139/00 20060101
C10M139/00; C10M 129/54 20060101 C10M129/54; C10M 135/10 20060101
C10M135/10; C10M 143/14 20060101 C10M143/14; C10M 133/44 20060101
C10M133/44; C10M 149/22 20060101 C10M149/22; C10M 161/00 20060101
C10M161/00 |
Claims
1. A lubricant composition, comprising: a controlled release
friction modifier (CRFM); 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 succinimide compound having an N:CO
ratio of 1.8 and a polyisobutylenyl number average molecular weight
of 750 to 2,500; a highly paraffinic base stock selected from the
group consisting of at least one Group III base stock, at least one
Group IV polyalphaolefin (PAO) base stock and combinations thereof;
a third dispersant; and a detergent.
2. The lubricant composition of claim 1, further comprising at
least one of a Group V co-base stock, an inorganic friction
modifier, a viscosity modifier, and a cleanliness booster.
3. The lubricant composition of claim 1, wherein the third
dispersant is selected from the group consisting of succinimide,
polyolefin amide alkeneamine, ethylene capped succinimide, borated
polyisobutylsuccinimide-polyamine, and mixtures thereof.
4. The lubricant composition of claim 1, wherein the detergent is
selected from the group consisting of highly overbased calcium
salicylate, low base calcium salicylate and overbased magnesium
sulfonate, neutral calcium sulfonate and mixtures thereof.
5. The lubricant composition of claim 3, wherein the Group V
co-base stock is selected from the group consisting of esters,
alkylated naphthalenes and mixtures thereof.
6. The lubricant composition of claim 1, wherein the PAO base stock
comprises up to 60 wt % of the composition.
7. The lubricant composition of claim 1, wherein the Group III base
stock comprises 10-90 wt % of the composition.
8. The lubricant composition of claim 1, wherein the third
dispersant comprises 1-12 wt % of the composition.
9. The lubricant composition of claim 1, wherein the detergent
comprises 1-8 wt % of the composition.
10. The lubricant composition of claim 1, wherein the CRFM
comprises 2-8 wt % of the composition.
11. A lubricant composition, comprising: a controlled release
friction modifier (CRFM) 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 succinimide compound having an N:CO
ratio of 1.8 and a polyisobutylenyl number average molecular weight
of 750 to 2,500; a highly paraffinic base stock selected from the
group consisting of at least one Group III base stock, at least one
Group IV polyalphaolefin (PAO) base stock or combinations thereof;
a third dispersant selected from the group consisting of
succinimide, polyolefin amide alkeneamine, ethylene capped
succinimide, borated polyisobutylsuccinimide-polyamine and mixtures
thereof; and a detergent selected from the group consisting of
highly overbased calcium salicylate, low base calcium salicylate
and overbased magnesium sulfonate, neutral calcium sulfonate and
mixtures thereof.
12. The lubricant composition of claim 11, further comprising at
least one of a Group V co-base stock, an inorganic friction
modifier, a viscosity modifier, and a cleanliness booster.
13. The lubricant composition of claim 12, wherein the Group V
co-base stock is selected from the group consisting of esters,
alkylated naphthalenes and mixtures thereof.
14. The lubricant composition of claim 11, wherein the PAO base
stock comprises up to 60 wt % of the composition.
15. The lubricant composition of claim 11, wherein the Group III
base stock comprises 10-90 wt % of the composition.
16. The lubricant composition of claim 11, wherein the third
dispersant comprises 1-12 wt % of the composition.
17. The lubricant composition of claim 11, wherein the detergent
comprises 1-8 wt % of the composition.
18. The lubricant composition of claim 11, wherein the CRFM
comprises 2-8 wt % of the composition.
19. A lubricant composition, comprising: a controlled release
friction modifier (CRFM) comprising 3.96 wt % of the composition,
the CRFM 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
succinimide compound having an N:CO ratio of 1.8 and a
polyisobutylenyl number average molecular weight of 750 to 2,500; a
highly paraffinic base stock comprising at least one Group III base
stock, at least one Group IV polyalphaolefin (PAO) base stock,
wherein the PAO base stock comprises 10-31.92 wt % of the
composition and the Group III base stock comprises 40-64.21 wt % of
the composition; a third dispersant, wherein the dispersant
comprises 4.44-5.4 wt % of the composition; and a detergent,
wherein the detergent comprises 2.03-3.83 wt % of the composition.
Description
[0001] This nonprovisional application claims priority to U.S.
Provisional Application No. 62/535,509, which was filed on Jul. 21,
2017, and is herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Disclosure
[0002] The present invention relates to a lubricant composition, in
particular to a lubricant composition suitable for use in internal
combustion engines, which promotes sustained improved fuel
economy.
Description of the Background Art
[0003] Lubricant compositions must provide crucial lubrication to
engines, but these compositions must also provide additional
benefits to the engines in which they are used. Such additional
benefits include fuel economy, oxidation stability of the
composition over time, control of deposit formation on internal
engine surfaces and maintenance of the filterability of the
composition. In addition, lubricant compositions must be formulated
to meet stringent government testing standards before it may be
used as a motor oil. Because of all of these requirements,
formulating a lubricant composition that meets these requirements
is quite difficult.
[0004] Various additives are included in a lubricant composition to
achieve the above benefits. Improving any of these benefits while
maintaining the others is challenging because a particular additive
that may improve one benefit will often negatively affect at least
one of the other required benefits of a lubricant composition. In
view of the chemical interactions both among the additives and
between the additives and the base stock used, developing a
formulation for a lubricant composition that provides the above
benefits is a difficult and complex task.
[0005] 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.
[0006] 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;
however, they do not describe compositions that have been
formulated to provide increased fuel economy that is sustained
while the lubricant composition ages. Accordingly, there exists a
need for improved lubricant compositions capable of providing
increased fuel economy that is sustained over the period during
which the composition is used, while meeting all of the
requirements for the use of a lubricant composition in an
engine.
[0007] A major source of energy loss within internal combustion
engines is the friction that occurs between lubricated parts that
are in sliding contact with each-other during the combustion cycle.
Critical engine parts that often contribute to these losses include
piston ring on liner contact, cam lobe contacts and journal
bearings. Friction modifiers are capable of changing the surface
properties of the materials commonly used in engines. Although both
inorganic (metal ash-containing) and organic (ash-free) friction
modifiers exist, organic friction modifiers are preferred as they
do not contribute to ash in the exhaust stream. It is well known
that friction modifiers (especially organic friction modifiers) are
quickly destroyed in high temperatures and oxidative environments
such as those that are present in a combustion engine. It is
therefore advantageous to develop formulations with Controlled
Release Friction Modifiers that allow for low friction benefits to
be retained hours, days, weeks and even months after the lubricant
has been added to the engine. The use of a controlled release
friction modifier can enable a vehicle to have better aged-oil fuel
economy than fresh oil fuel economy. This is important for
minimizing the carbon intensity of the lubricant over the entire
lubricant drain interval. However, controlled release friction
modifiers often are accompanied by solubility limitations of the
friction modifier, poor deposit performance and poor filterability
of the finished lubricant. Until now, this has prohibited the
development of high-performing controlled release friction modified
formulations.
[0008] Fuel economy, enabled by an engine oil lubricant, is a key
specification for automotive lubricants. 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 a modern
engine oil. Others include 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 lubricants
performance works against the performance enabled by other
additives. Current well known fuel economy additives include
various oil-soluble compounds of molybdenum as well as NOCH
(nitrogen, oxygen-containing chemistries). The highest performance
lubricants usually entail the use of base oils that are highly
paraffinic. Such base oils would include API Group IV PAO's, API
Group III's such as gas-to-liquids base oils and potentially even
highly saturated Group II base oils. Such oils are highly
non-polar, and as a result have a limited solubility for polar
additives. Most of the fuel economy additives are highly polar and
as such are challenged to remain soluble in the lube 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 used up in service, with the result that
fuel economy is more difficult to maintain for extended times. A
key indicator of this would be tests such as the API/ILSAC Seq. VID
or VIE, which measures the fuel economy of both fresh and aged oils
against a reference.
SUMMARY OF THE INVENTION
[0009] 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 engine fuel economy by providing a controlled release
friction modified lubricant formulation with sustained fuel
economy.
[0010] Exemplary embodiments of the invention are directed to a
lubricant composition that includes a controlled release friction
modifier (CRFM), a highly paraffinic base stock selected from at
least one Group III base stock, at least one Group IV
polyalphaolefin (PAO) base stock, or combinations thereof, a
dispersant, and a detergent. In certain embodiments, the CRFM
comprises an ionic tetrahedral borate compound including a cation
and a tetrahedral borate anion, wherein the tetrahedral borate
anion comprises a boron atom having two bidentate di-oxo ligands of
C.sub.18 tartrimide.
[0011] In certain embodiments, the lubricant composition also
includes at least one of a Group V co-base stock, an inorganic
friction modifier, a viscosity modifier, and a cleanliness
booster.
[0012] Exemplary lubricant compositions of the present invention
can be used as engine lubricants that promote fuel economy in
internal combustion engines. This fuel economy is not only
sustained, but actually increases over the time the composition is
utilized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] 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:
[0014] FIG. 1 illustrates comparative aging profile results from
engine test stand testing of a composition consistent with
embodiments of the present invention.
[0015] FIG. 2 illustrates comparative fuel economy change
calculated from results of full chassis dynamometer testing of a
composition consistent with embodiments of the present
invention.
DETAILED DESCRIPTION
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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. In some embodiments, the lubricant composition
comprises a controlled release friction modifier (CRFM).
Additionally, in some embodiments, the lubricant composition
further comprises a highly paraffinic base stock selected from at
least one an American Petroleum Institute (API) Group III base
stock, at least one API Group IV polyalphaolefin (PAO) base stock,
or combinations thereof, a dispersant and a detergent. In some
embodiments, the lubricant composition further comprises at least
one of, a Group V co-base stock, an inorganic friction modifier, a
viscosity modifier, a cleanliness booster, as well as other
lubricant composition additives.
[0020] Controlled Release Friction Modifier (CRFM)
[0021] 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.
[0022] 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.
[0023] The above described ionic tetrahedral borate compound can
serve as a friction modifier, in a lubricating composition.
[0024] 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##
[0025] where R3 and R4 form a 5 membered nitrogen-containing
heterocyclic ring substituted with a linear C18 group.
[0026] 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.
[0027] 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").
[0028] 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).
[0029] 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.
[0030] In an embodiment the linear C18 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, I-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 RNH2 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.
[0031] Suitable trivalent boron compounds include borate esters of
the general form B(OR)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.
[0032] In an embodiment, the ionic borate compound is the reaction
product of a tartrimide, a borate ester, and a basic component,
such as two dispersants, to form a "boro-tartrimide" friction
modifier. The ionic boron compound described herein is used to
improve friction.
[0033] 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 known 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.
[0034] 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 %.
[0035] Base Stocks
[0036] 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.
[0037] 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 an oil that has been
previously used as feed stock.
[0038] Diverse groups of lubricant base stocks are known in the
art. 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 about
80 to 120 and contain greater than about 0.03% sulfur and less than
about 90% saturates. Group II base stocks have a viscosity index of
between about 80 to 120, and contain less than or equal to about
0.03% sulfur and greater than or equal to about 90% saturates.
Group III stocks have a viscosity index greater than or equal to
120 and contain less than or equal to about 0.03% sulfur and
greater than about 90% saturates. Group IV includes
polyalphaolefins (PAO). Group V base stock includes base stocks not
included in Groups I-IV. Table 1 below summarizes properties of
each of these five groups.
TABLE-US-00001 TABLE 1 Base Oil Properties Saturates Sulfur
Viscosity Index Group I <90 and/or >0.03% and .gtoreq.80 and
<120 Group II .gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and
<120 Group III .gtoreq.90 and .ltoreq.0.03% and .gtoreq.120
Group IV polyalphaolefins (PAO) Group V All other base oil stocks
not included in Groups I, II, III, or IV
[0039] 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.
[0040] 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.
[0041] 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 C8, C10, C12, C14 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.
[0042] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron
Phillips Chemical Company, BP, and others, typically vary from
about 250 to about 3,000, although PAO's may be made in viscosities
up to about 150 cSt (100.degree. C.). The PAOs are typically
comprised of relatively low molecular weight hydrogenated polymers
or oligomers of alphaolefins which include, but are not limited to,
C2 to about C32 alphaolefins with the C8 to about C16 alphaolefins,
such as 1-octene, 1-decene, 1-dodecene and the like, being
preferred. The preferred polyalphaolefins are poly-1-octene,
poly-1-decene and poly-1-dodecene and mixtures thereof and mixed
olefin-derived polyolefins. However, the dimers of higher olefins
in the range of C14 to C18 may be used to provide low viscosity
base stocks of acceptably low volatility. Depending on the
viscosity grade and the starting oligomer, the PAOs may be
predominantly trimers and tetramers of the starting olefins, with
minor amounts of the higher oligomers, having a viscosity range of
1.5 to 12 cSt. PAO fluids of particular use may include 3.0 cSt,
3.4 cSt, and/or 3.6 cSt and combinations thereof. Mixtures of PAO
fluids having a viscosity range of 1.5 to approximately 150 cSt or
more may be used if desired.
[0043] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. No. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C14 to C18 olefins are
described in U.S. Pat. No. 4,218,330.
[0044] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof. Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (LHDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269, the disclosure of which is incorporated
herein by reference in its entirety. Processes for making
hydrocracked/hydroisomerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Each of the aforementioned patents is incorporated
herein in their entirety. Particularly favorable processes are
described in European Patent Application Nos. 464546 and 464547,
also incorporated herein by reference. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. Nos. 4,594,172
and 4,943,672, the disclosures of which are incorporated herein by
reference in their entirety.
[0045] Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived
base oils, and other wax-derived hydroisomerized (wax isomerate)
base oils be advantageously used in the instant disclosure, and may
have useful kinematic viscosities at 100.degree. C. of about 3 cSt
to about 50 cSt, preferably about 3 cSt to about 30 cSt, more
preferably about 3.5 cSt to about 25 cSt, as exemplified by GTL 4
with kinematic viscosity of about 4.0 cSt at 100.degree. C. and a
viscosity index of about 141. These Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and other wax-derived
hydroisomerized base oils may have useful pour points of about
-20.degree. C. or lower, and under some conditions may have
advantageous pour points of about -25.degree. C. or lower, with
useful pour points of about -30.degree. C. to about -40.degree. C.
or lower. Useful compositions of Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and wax-derived
hydroisomerized base oils are recited in U.S. Pat. Nos. 6,080,301;
6,090,989, and 6,165,949 for example, and are incorporated herein
in their entirety by reference.
[0046] The hydrocarbyl aromatics can be used as a base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least about 5% of its weight derived from an aromatic moiety such
as a benzenoid moiety or naphthenoid moiety, or their derivatives.
These hydrocarbyl aromatics include alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and the like. The aromatic can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can also be comprised
of mixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl
groups, cycloalkenyl groups and other related hydrocarbyl groups.
The hydrocarbyl groups can range from about C6 up to about C60 with
a range of about C8 to about C20 often being preferred. A mixture
of hydrocarbyl groups is often preferred, and up to about three
such substituents may be present. The hydrocarbyl group can
optionally contain sulfur, oxygen, and/or nitrogen containing
substituents. The aromatic group can also be derived from natural
(petroleum) sources, provided at least about 5% of the molecule is
comprised of an above-type aromatic moiety. Viscosities at
100.degree. C. of approximately 3 cSt to about 50 cSt are
preferred, with viscosities of approximately 3.4 cSt to about 20
cSt often being more preferred for the hydrocarbyl aromatic
component. In an embodiment, an alkyl naphthalene where the alkyl
group is primarily comprised of 1-hexadecene is used. Other
alkylates of aromatics can be advantageously used. Naphthalene or
methyl naphthalene, for example, can be alkylated with olefins such
as octene, decene, dodecene, tetradecene or higher, mixtures of
similar olefins, and the like. Useful concentrations of hydrocarbyl
aromatic in a lubricant oil composition can be about 2% to about
25%, preferably about 4% to about 20%, and more preferably about 4%
to about 15%, depending on the application.
[0047] Alkylated aromatics such as the hydrocarbyl aromatics of the
present disclosure may be produced by well-known Friedel-Crafts
alkylation of aromatic compounds. See Friedel-Crafts and Related
Reactions, Olah, G. A. (ed.), Inter-science Publishers, New York,
1963. For example, an aromatic compound, such as benzene or
naphthalene, is alkylated by an olefin, alkyl halide or alcohol in
the presence of a Friedel-Crafts catalyst. See Friedel-Crafts and
Related Reactions, Vol. 2, part 1, chapters 14, 17, and 18, See
Olah, G. A. (ed.), Inter-science Publishers, New York, 1964. Many
homogeneous or heterogeneous, solid catalysts are known to one
skilled in the art. The choice of catalyst depends on the
reactivity of the starting materials and product quality
requirements. For example, strong acids such as AlCl3, BF3, or HF
may be used. In some cases, milder catalysts such as FeCl3 or SnCl4
are preferred. Newer alkylation technology uses zeolites or solid
super acids.
[0048] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0049] 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 C5 to C30
acids such as saturated straight chain fatty acids including
caprylic acid, capric acid, lauric acid, myristic acid, palmitic
acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures of any of these materials.
[0050] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
monocarboxylic acids containing from about 5 to about 10 carbon
atoms. These esters are widely available commercially, for example,
the Mobil P-41 and P-51 esters of ExxonMobil Chemical Company.
[0051] Also useful are esters derived from renewable material such
as coconut, palm, rapeseed, soy, sunflower and the like. These
esters may be monoesters, di-esters, polyol esters, complex esters,
or mixtures thereof. These esters are widely available
commercially, for example, the Mobil P-51 ester of ExxonMobil
Chemical Company.
[0052] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0053] Non-conventional or unconventional base stocks/base oils
include one or more of a mixture of base stock(s) derived from one
or more Gas-to-Liquids (GTL) materials, as well as
isomerate/isodewaxate base stock(s) derived from natural wax or
waxy feeds, mineral and or non-mineral oil waxy feed stocks such as
slack waxes, natural waxes, and waxy stocks such as gas oils, waxy
fuels hydrocracker bottoms, waxy raffinate, hydrocrackate, thermal
crackates, or other mineral, mineral oil, or even non-petroleum oil
derived waxy materials such as waxy materials received from coal
liquefaction or shale oil, and mixtures of such base stocks.
[0054] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds and/or elements as feed
stocks such as hydrogen, carbon dioxide, carbon monoxide, water,
methane, ethane, ethylene, acetylene, propane, propylene, propyne,
butane, butylenes, and butynes. GTL base stocks and/or base oils
are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons; for example, waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feed stocks. GTL base stock(s) and/or base oil(s)
include oils boiling in the lube oil boiling range (1)
separated/fractionated from synthesized GTL materials such as, for
example, by distillation and subsequently subjected to a final wax
processing step which involves either or both of a catalytic
dewaxing process, or a solvent dewaxing process, to produce lube
oils of reduced/low pour point; (2) synthesized wax isomerates,
comprising, for example, hydrodewaxed or hydroisomerized cat and/or
solvent dewaxed synthesized wax or waxy hydrocarbons; (3)
hydrodewaxed or hydroisomerized cat and/or solvent dewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates); preferably
hydrodewaxed or hydroisomerized/followed by cat and/or solvent
dewaxing dewaxed F-T waxy hydrocarbons, or hydrodewaxed or
hydroisomerized/followed by cat (or solvent) dewaxing dewaxed, F-T
waxes, or mixtures thereof.
[0055] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from about 2 mm2/s to about 50 mm2/s (ASTM D445).
They are further characterized typically as having pour points of
-5.degree. C. to about -40.degree. C. or lower (ASTM D97). They are
also characterized typically as having viscosity indices of about
80 to about 140 or greater (ASTM D2270).
[0056] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) typically have very low sulfur and
nitrogen content, generally containing less than about 10 ppm, and
more typically less than about 5 ppm of each of these elements. The
sulfur and nitrogen content of GTL base stock(s) and/or base oil(s)
obtained from F-T material, especially F-T wax, is essentially nil.
In addition, the absence of phosphorous and aromatics make this
materially especially suitable for the formulation of low SAP
products.
[0057] The term GTL base stock and/or base oil and/or wax isomerate
base stock and/or base oil is to be understood as embracing
individual fractions of such materials of wide viscosity range as
recovered in the production process, mixtures of two or more of
such fractions, as well as mixtures of one or two or more low
viscosity fractions with one, two or more higher viscosity
fractions to produce a blend wherein the blend exhibits a target
kinematic viscosity.
[0058] The GTL material, from which the GTL base stock(s) and/or
base oil(s) is/are derived is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0059] Base oils for use in the formulated lubricating oils useful
in the present disclosure are any of the variety of oils
corresponding to API Group 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.
[0060] In certain embodiments of the present invention, the
lubricant composition includes Group III base stocks. The utilized
Group III base stocks are not particularly limited. Any base stocks
which corresponds to API Group III can be used. Additionally, a
single Group III base stock can be used, or multiple Group III base
stocks can be used in combination.
[0061] In certain embodiments of the present invention, the Group
III base stock is present as 10-90 wt % of the total weight of the
lubricant composition. The Group III base stock is preferably
present as 30-70 wt % of the total weight of the lubricant
composition, and more preferably, the Group III base stock is
present as 10-64.21 wt % of the total weight of the lubricant
composition.
[0062] In certain embodiments of the present invention, the
lubricating composition includes Polyalphaolefin (PAO) oil base
stocks. PAOs, which are Group IV API base stocks, are a commonly
used synthetic hydrocarbon oil. The PAOs of the present invention
are not particularly limited. Any PAOs can be used. A single PAO
can be used, or multiple PAOs can be used in combination.
[0063] In certain embodiments of the present invention, the PAOs
are present as up to 60 wt % of the total weight of the lubricant
composition. The PAOs are preferably present as 5-50 wt % of the
total weight of the lubricant composition, and more preferably, the
PAOs are present as 10-31.92 wt % of the total weight of the
lubricant composition.
[0064] In certain embodiments of the present invention, a Group V
co-base stock is included in the lubricant composition. For
example, utilized Group V co-base stocks may include esters,
alkylated naphthalenes or mixtures thereof.
[0065] In certain embodiments of the present invention, the Group V
co-base stock is present as 0-15 wt % of the total weight of the
lubricant composition. The Group V co-base stock is preferably
present as 0-10 wt % of the total weight of the lubricant
composition, and more preferably, the Group V co-base stock is
present as 5 wt % of the total weight of the lubricant
composition.
[0066] Additives
[0067] In addition to the CRFM and any utilized base stocks,
certain embodiments of the present invention may additionally
contain one or more of commonly used lubricating oil performance
additives, which include but are not limited to detergents,
antiwear additives, dispersants, viscosity modifiers, corrosion
inhibitors, rust inhibitors, metal deactivators, extreme pressure
additives, anti-seizure agents, wax modifiers, viscosity modifiers,
fluid-loss additives, seal compatibility agents, lubricity agents,
anti-staining agents, chromophoric agents, defoamants,
demulsifiers, emulsifiers, densifiers, wetting agents, gelling
agents, tackiness agents, colorants, cleanliness boosters and
others. For a review of many commonly used additives, see Klamann
in Lubricants and Related Products, Verlag Chemie, Deerfield Beach,
Fla.; ISBN 0-89573-177-0. Reference is also made to "Lubricant
Additives" by M. W. Ranney, published by Noyes Data Corporation of
Parkridge, N.J. (1973); see also U.S. Pat. No. 7,704,930, the
disclosure of which is incorporated herein in its entirety. These
additives are commonly delivered with varying amounts of diluent
oil, that may range from 5 wt % to 50 wt %.
[0068] The additives useful in this disclosure do not have to be
soluble in the lubricant composition. Insoluble additives such as
zinc stearate in oil can be dispersed in the lubricant composition
of this disclosure.
[0069] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
[0070] 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.
[0071] Dispersants
[0072] In some embodiments of the present invention, one or more
dispersants may be included in the lubricant composition. 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.
[0073] 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.
[0074] A particularly useful class of dispersants are the
(poly)alkenylsuccinic derivatives, typically produced by the
reaction of a long chain hydrocarbyl substituted succinic compound,
usually a hydrocarbyl substituted succinic anhydride, with a
polyhydroxy or polyamino compound. The long chain hydrocarbyl group
constituting the oleophilic portion of the molecule which confers
solubility in the oil, is normally a polyisobutylene group. Many
examples of this type of dispersant are well known commercially and
in the literature. Exemplary U.S. patents describing such
dispersants are U.S. Pat. Nos. 3,172,892; 3,2145,707; 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.
[0075] Hydrocarbyl-substituted succinic acid and
hydrocarbyl-substituted succinic anhydride derivatives are useful
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0076] Succinimides are formed by the condensation reaction between
hydrocarbyl substituted succinic anhydrides and amines. Molar
ratios can vary depending on the polyamine. For example, the molar
ratio of hydrocarbyl substituted succinic anhydride to TEPA can
vary from about 1:1 to about 5:1. Representative examples are shown
in U.S. Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746;
3,322,670; and U.S. Pat. Nos. 3,652,616, 3,948,800; and Canada
Patent No. 1,094,044.
[0077] Succinate esters are formed by the condensation reaction
between hydrocarbyl substituted succinic anhydrides and alcohols or
polyols. Molar ratios can vary depending on the alcohol or polyol
used. For example, the condensation product of a hydrocarbyl
substituted succinic anhydride and pentaerythritol is a useful
dispersant.
[0078] Succinate ester amides are formed by condensation reaction
between hydrocarbyl substituted succinic anhydrides and alkanol
amines. For example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0079] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500 or more. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid. The above
products can also be post reacted with boron compounds such as
boric acid, borate esters or highly borated dispersants, to form
borated dispersants generally having from about 0.1 to about 5
moles of boron per mole of dispersant reaction product.
[0080] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, which is incorporated herein by reference. Process aids
and catalysts, such as oleic acid and sulfonic acids, can also be
part of the reaction mixture. Molecular weights of the alkylphenols
range from 800 to 2,500. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0081] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this disclosure can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HNR2 group-containing reactants.
[0082] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197.
[0083] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
about 500 to about 5000, or from about 1000 to about 3000, or about
1000 to about 2000, or a mixture of such hydrocarbylene groups,
often with high terminal vinylic groups. Other preferred
dispersants include succinic acid-esters and amides,
alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components.
[0084] Polymethacrylate or polyacrylate derivatives are another
class of dispersants. These dispersants are typically prepared by
reacting a nitrogen containing monomer and a methacrylic or acrylic
acid esters containing 5-25 carbon atoms in the ester group.
Representative examples are shown in U.S. Pat. Nos. 2,100,993, and
6,323,164. Polymethacrylate and polyacrylate dispersants are
normally used as multifunctional viscosity modifiers. The lower
molecular weight versions can be used as lubricant dispersants or
fuel detergents.
[0085] Illustrative preferred dispersants useful in this disclosure
include those derived from polyalkenyl-substituted mono- or
dicarboxylic acid, anhydride or ester, which dispersant has a
polyalkenyl moiety with a number average molecular weight of at
least 900 and from greater than 1.3 to 1.7, preferably from greater
than 1.3 to 1.6, most preferably from greater than 1.3 to 1.5,
functional groups (mono- or dicarboxylic acid producing moieties)
per polyalkenyl moiety (a medium functionality dispersant).
Functionality (F) can be determined according to the following
formula:
F=(SAP.times.Mn)/((112,200.times.A.I.)-(SAP.times.98))
[0086] wherein SAP is the saponification number (i.e., the number
of milligrams of KOH consumed in the complete neutralization of the
acid groups in one gram of the succinic-containing reaction
product, as determined according to ASTM D94); Mn is the number
average molecular weight of the starting olefin polymer; and A.I.
is the percent active ingredient of the succinic-containing
reaction product (the remainder being unreacted olefin polymer,
succinic anhydride and diluent).
[0087] The polyalkenyl moiety of the dispersant may have a number
average molecular weight of at least 900, suitably at least 1500,
preferably between 1800 and 3000, such as between 2000 and 2800,
more preferably from about 2100 to 2500, and most preferably from
about 2200 to about 2400. The molecular weight of a dispersant is
generally expressed in terms of the molecular weight of the
polyalkenyl moiety. This is because the precise molecular weight
range of the dispersant depends on numerous parameters including
the type of polymer used to derive the dispersant, the number of
functional groups, and the type of nucleophilic group employed.
[0088] Polymer molecular weight, specifically Mn, can be determined
by various known techniques. One convenient method is gel
permeation chromatography (GPC), which additionally provides
molecular weight distribution information (see W. W. Yau, J. J.
Kirkland and D. D. Bly, "Modern Size Exclusion Liquid
Chromatography", John Wiley and Sons, New York, 1979). Another
useful method for determining molecular weight, particularly for
lower molecular weight polymers, is vapor pressure osmometry (e.g.,
ASTM D3592).
[0089] The polyalkenyl moiety in a dispersant preferably has a
narrow molecular weight distribution (MWD), also referred to as
polydispersity, as determined by the ratio of weight average
molecular weight (Mw) to number average molecular weight (Mn).
Polymers having a Mw/Mn of less than 2.2, preferably less than 2.0,
are most desirable. Suitable polymers have a polydispersity of from
about 1.5 to 2.1, preferably from about 1.6 to about 1.8.
[0090] Suitable polyalkenes employed in the formation of the
dispersants include homopolymers, interpolymers or lower molecular
weight hydrocarbons. One family of such polymers comprise polymers
of ethylene and/or at least one C3 to C2 alpha-olefin having the
formula H2C=CHR1 wherein R1 is a straight or branched chain alkyl
radical comprising 1 to 26 carbon atoms and wherein the polymer
contains carbon-to-carbon unsaturation, and a high degree of
terminal ethenylidene unsaturation. Preferably, such polymers
comprise interpolymers of ethylene and at least one alpha-olefin of
the above formula, wherein R1 is alkyl of from 1 to 18 carbon
atoms, and more preferably is alkyl of from 1 to 8 carbon atoms,
and more preferably still of from 1 to 2 carbon atoms.
[0091] Another useful class of polymers is polymers prepared by
cationic polymerization of monomers such as isobutene and styrene.
Common polymers from this class include polyisobutenes obtained by
polymerization of a C4 refinery stream having a butene content of
35 to 75% by wt., and an isobutene content of 30 to 60% by wt. A
preferred source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feedstocks are disclosed in
the art such as in U.S. Pat. No. 4,952,739. A preferred embodiment
utilizes polyisobutylene prepared from a pure isobutylene stream or
a Raffinate I stream to prepare reactive isobutylene polymers with
terminal vinylidene olefins. Polyisobutene polymers that may be
employed are generally based on a polymer chain of from 1500 to
3000.
[0092] The dispersant(s) are preferably non-polymeric (e.g., mono-
or bis-succinimides). Such dispersants can be prepared by
conventional processes such as disclosed in U.S. Patent Application
Publication No. 2008/0020950, the disclosure of which is
incorporated herein by reference.
[0093] The dispersant(s) can be borated by conventional means, as
generally disclosed in U.S. Pat. Nos. 3,087,936, 3,254,025 and
5,430,105.
[0094] In some embodiments of the present invention, utilized
dispersants may include, for example, succinimide, polyolefin amide
alkeneamine, ethylene capped succinimide, borated
polyisobutylsuccinimide-polyamine or mixtures thereof.
[0095] In certain embodiments of the present invention, the
dispersants are present as 1-12 wt % of the total weight of the
lubricant composition. The dispersants are preferably present as
2-8 wt % of the total weight of the lubricant composition, and more
preferably, the dispersants are present as 4.44-5.4 wt % of total
weight of the lubricant composition.
[0096] As used herein, the dispersant concentrations are given on
an "as delivered" basis. Typically, the active dispersant is
delivered with a process oil. The "as delivered" dispersant
typically contains from about 20 weight percent to about 80 weight
percent, or from about 40 weight percent to about 60 weight
percent, of active dispersant in the "as delivered" dispersant
product.
[0097] Detergents
[0098] In certain embodiments of the present invention, detergents
may be included in the lubricant composition. Illustrative
detergents useful in this disclosure include, for example, alkali
metal detergents, alkaline earth metal detergents, or mixtures of
one or more alkali metal detergents and one or more alkaline earth
metal detergents. A typical detergent is an anionic material that
contains a long chain hydrophobic portion of the molecule and a
smaller anionic or oleophobic hydrophilic portion of the molecule.
The anionic portion of the detergent is typically derived from an
organic acid such as a sulfur acid, carboxylic acid (e.g.,
salicylic acid), phosphorous acid, phenol, or mixtures thereof. The
counterion is typically an alkaline earth or alkali metal. The
detergent can be overbased as described herein.
[0099] The detergent is preferably a metal salt of an organic or
inorganic acid, a metal salt of a phenol, or mixtures thereof. The
metal is preferably selected from an alkali metal, an alkaline
earth metal, and mixtures thereof. The organic or inorganic acid is
selected from an aliphatic organic or inorganic acid, a
cycloaliphatic organic or inorganic acid, an aromatic organic or
inorganic acid, and mixtures thereof.
[0100] The metal is preferably selected from an alkali metal, an
alkaline earth metal, and mixtures thereof. More preferably, the
metal is selected from calcium (Ca), magnesium (Mg), and mixtures
thereof.
[0101] The organic acid or inorganic acid is preferably selected
from a sulfur acid, a carboxylic acid, a phosphorus acid, and
mixtures thereof.
[0102] Preferably, the metal salt of an organic or inorganic acid
or the metal salt of a phenol comprises calcium phenate, calcium
sulfonate, calcium salicylate, magnesium phenate, magnesium
sulfonate, magnesium salicylate, an overbased detergent, and
mixtures thereof.
[0103] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased. These detergents can be used in
mixtures of neutral, overbased, highly overbased calcium
salicylate, sulfonates, phenates and/or magnesium salicylate,
sulfonates, phenates. The TBN ranges can vary from low, medium to
high TBN products, including as low as 0 to as high as 600.
Mixtures of low, medium, high TBN can be used, along with mixtures
of calcium and magnesium metal based detergents, and including
sulfonates, phenates, salicylates, and carboxylates. A detergent
mixture with a metal ratio of 1, in conjunction of a detergent with
a metal ratio of 2, and as high as a detergent with a metal ratio
of 5, can be used. Borated detergents can also be used.
[0104] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH)2, BaO, Ba(OH)2, MgO, Mg(OH)2,
for example) with an alkyl phenol or sulfurized alkylphenol. Useful
alkyl groups include straight chain or branched C1-C30 alkyl
groups, preferably, C4-C20 or mixtures thereof. Examples of
suitable phenols include isobutylphenol, 2-ethylhexylphenol,
nonylphenol, dodecyl phenol, and the like. It should be noted that
starting alkylphenols may contain more than one alkyl substituent
that are each independently straight chain or branched and can be
used from 0.5 to 6 weight percent. When a non-sulfurized
alkylphenol is used, the sulfurized product may be obtained by
methods well known in the art. These methods include heating a
mixture of alkylphenol and sulfurizing agent (including elemental
sulfur, sulfur halides such as sulfur dichloride, and the like) and
then reacting the sulfurized phenol with an alkaline earth metal
base.
[0105] In accordance with this disclosure, metal salts of
carboxylic acids are preferred detergents. These carboxylic acid
detergents may be prepared by reacting a basic metal compound with
at least one carboxylic acid and removing free water from the
reaction product. These compounds may be overbased to produce the
desired TBN level. Detergents made from salicylic acid are one
preferred class of detergents derived from carboxylic acids. Useful
salicylates include long chain alkyl salicylates. One useful family
of compositions is of the formula
##STR00002##
[0106] where R is an alkyl group having 1 to about 30 carbon atoms,
n is an integer from 1 to 4, and M is an alkaline earth metal.
Preferred R groups are alkyl chains of at least C11, preferably C13
or greater. R may be optionally substituted with substituents that
do not interfere with the detergent's function. M is preferably,
calcium, magnesium, or barium. More preferably, M is calcium.
[0107] Hydrocarbyl-substituted salicylic acids may be prepared from
phenols by the Kolbe reaction (see U.S. Pat. No. 3,595,791). The
metal salts of the hydrocarbyl-substituted salicylic acids may be
prepared by double decomposition of a metal salt in a polar solvent
such as water or alcohol.
[0108] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0109] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039.
[0110] In some embodiments of the present invention, utilized
detergents may include, for example, highly overbased calcium
salicylate, low base calcium salicylate, overbased magnesium
sulfonate, neutral calcium sulfonate or mixtures thereof.
[0111] In certain embodiments of the present invention, the
detergents are present as 1-8 wt % of the total weight of the
lubricant composition. The detergents are preferably present as 1-5
wt % of the total weight of the lubricant composition, and more
preferably, the detergents are present as 2.03-3.83 wt % of total
weight of the lubricant composition.
[0112] As used herein, the detergent concentrations are given on an
"as delivered" basis. Typically, the active detergent is delivered
with a process oil. The "as delivered" detergent typically contains
from about 20 weight percent to about 100 weight percent, or from
about 40 weight percent to about 60 weight percent, of active
detergent in the "as delivered" detergent product.
[0113] Friction Modifiers
[0114] In certain embodiments of the present invention, the
lubricant composition may include additional friction modifiers.
Illustrative friction modifiers may include, for example,
organometallic compounds or materials, or mixtures thereof.
Illustrative organometallic friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, molybdenum amine, molybdenum diamine, an
organotungstenate, a molybdenum dithiocarbamate, molybdenum
dithiophosphates, molybdenum amine complexes, molybdenum
carboxylates, and the like, and mixtures thereof. Similar tungsten
based compounds may be preferable.
[0115] Other illustrative friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, alkoxylated fatty acid esters, alkanolamides, polyol fatty
acid esters, borated glycerol fatty acid esters, fatty alcohol
ethers, and mixtures thereof.
[0116] Illustrative alkoxylated fatty acid esters include, for
example, polyoxyethylene stearate, fatty acid polyglycol ester, and
the like. These can include polyoxypropylene stearate,
polyoxybutylene stearate, polyoxyethylene isosterate,
polyoxypropylene isostearate, polyoxyethylene palmitate, and the
like.
[0117] Illustrative alkanolamides include, for example, lauric acid
diethylalkanolamide, palmic acid diethylalkanolamide, and the like.
These can include oleic acid diethyalkanolamide, stearic acid
diethylalkanolamide, oleic acid diethylalkanolamide,
polyethoxylated hydrocarbylamides, polypropoxylated
hydrocarbylamides, and the like.
[0118] Illustrative polyol fatty acid esters include, for example,
glycerol mono-oleate, saturated mono-, di-, and tri-glyceride
esters, glycerol mono-stearate, and the like. These can include
polyol esters, hydroxyl-containing polyol esters, and the like.
[0119] Illustrative borated glycerol fatty acid esters include, for
example, borated glycerol mono-oleate, borated saturated mono-,
di-, and tri-glyceride esters, borated glycerol mono-sterate, and
the like. In addition to glycerol polyols, these can include
trimethylolpropane, pentaerythritol, sorbitan, and the like. These
esters can be polyol monocarboxylate esters, polyol dicarboxylate
esters, and on occasion polyoltricarboxylate esters. Preferred can
be the glycerol mono-oleates, glycerol dioleates, glycerol
trioleates, glycerol monostearates, glycerol distearates, and
glycerol tristearates and the corresponding glycerol
monopalmitates, glycerol dipalmitates, and glycerol tripalmitates,
and the respective isostearates, linoleates, and the like. On
occasion the glycerol esters can be preferred as well as mixtures
containing any of these. Ethoxylated, propoxylated, butoxylated
fatty acid esters of polyols, especially using glycerol as
underlying polyol can be preferred.
[0120] Illustrative fatty alcohol ethers include, for example,
stearyl ether, myristyl ether, and the like. Alcohols, including
those that have carbon numbers from C3 to C50, can be ethoxylated,
propoxylated, or butoxylated to form the corresponding fatty alkyl
ethers. The underlying alcohol portion can preferably be stearyl,
myristyl, C11-C13 hydrocarbon, oleyl, isosteryl, and the like.
[0121] The lubricating oils of this disclosure exhibit desired
properties, e.g., wear control, in the presence or absence of a
friction modifier.
[0122] Concentrations of molybdenum-containing materials are often
described in terms of Mo metal concentration. Advantageous
concentrations of Mo may range from 25 ppm to 700 ppm or more, and
often with a preferred range of 50-200 ppm. Friction modifiers of
all types may be used alone or in mixtures with the materials of
this disclosure. Often mixtures of two or more friction modifiers,
or mixtures of friction modifier(s) with alternate surface active
material(s), are also desirable.
[0123] In certain embodiments of the present invention, friction
modifiers, in addition to the amount of CRFM, may be present as 0-1
wt % of the total weight of the lubricant composition. The friction
modifiers, in addition to the amount of CRFM, are preferably
present as 0-0.6 wt % of the total weight of the lubricant
composition, and more preferably, the friction modifiers, in
addition to the amount of CRFM, are present as 0.2-0.4 wt % of
total weight of the lubricant composition.
[0124] Viscosity Modifiers
[0125] In some embodiments of the present invention, viscosity
modifiers, also known as viscosity index improvers (VI improvers),
and viscosity improvers, can be included in the lubricant
composition.
[0126] Viscosity modifiers provide lubricants with high and low
temperature operability. These additives impart shear stability at
elevated temperatures and acceptable viscosity at low
temperatures.
[0127] Suitable viscosity modifiers include high molecular weight
hydrocarbons, polyesters and viscosity modifier dispersants that
function as both a viscosity modifier and a dispersant. Typical
molecular weights of these polymers are between about 10,000 to
1,500,000, more typically about 20,000 to 1,200,000, and even more
typically between about 50,000 and 1,000,000.
[0128] Examples of suitable viscosity modifiers are linear or
star-shaped polymers and copolymers of methacrylate, butadiene,
olefins, or alkylated styrenes. Polyisobutylene is a commonly used
viscosity modifier. Another suitable viscosity modifier is
polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity modifiers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
50,000 to 200,000 molecular weight.
[0129] Olefin copolymers are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921" and "PARATONE.RTM. 8941"); from Afton
Chemical Corporation under the trade designation "HiTEC.RTM." (such
as "HiTEC.RTM. 5850B"; and from The Lubrizol Corporation under the
trade designation "Lubrizol.RTM. 7067C". Hydrogenated polyisoprene
star polymers are commercially available from Infineum
International Limited, e.g., under the trade designation "SV200"
and "SV600". Hydrogenated diene-styrene block copolymers are
commercially available from Infineum International Limited, e.g.,
under the trade designation "SV 50".
[0130] The polymethacrylate or polyacrylate polymers can be linear
polymers which are available from Evnoik Industries under the trade
designation "Viscoplex.RTM." (e.g., Viscoplex 6-954) or star
polymers which are available from Lubrizol Corporation under the
trade designation Asteric.TM. (e.g., Lubrizol 87708 and Lubrizol
87725).
[0131] Illustrative vinyl aromatic-containing polymers useful in
this disclosure may be derived predominantly from vinyl aromatic
hydrocarbon monomer. Illustrative vinyl aromatic-containing
copolymers useful in this disclosure may be represented by the
following general formula:
A-B
[0132] wherein A is a polymeric block derived predominantly from
vinyl aromatic hydrocarbon monomer, and B is a polymeric block
derived predominantly from conjugated diene monomer.
[0133] In certain embodiments of the present invention, viscosity
modifiers may be present as 1-12 wt % of the total weight of the
lubricant composition. The viscosity modifiers are preferably
present as 3-8 wt % of the total weight of the lubricant
composition, and more preferably, the viscosity modifiers are
present as 5.6-6.4 wt % of total weight of the lubricant
composition. Viscosity modifiers are typically added as
concentrates, in large amounts of diluent oil.
[0134] As used herein, the viscosity modifier concentrations are
given on an "as delivered" basis. Typically, the active polymer is
delivered with a diluent oil. The "as delivered" viscosity modifier
typically contains from 20 weight percent to 75 weight percent of
an active polymer for polymethacrylate or polyacrylate polymers, or
from 8 weight percent to 20 weight percent of an active polymer for
olefin copolymers, hydrogenated polyisoprene star polymers, or
hydrogenated diene-styrene block copolymers, in the "as delivered"
polymer concentrate.
[0135] Cleanliness Boosters
[0136] In certain embodiments of the present invention, the
lubricant composition includes cleanliness boosters. The
cleanliness boosters of the present invention are not particularly
limited. Any cleanliness boosters can be used. A single cleanliness
booster can be used, or multiple cleanliness boosters can be used
in combination. 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 (DB2),
polyisobutylene or a combination thereof.
[0137] In certain embodiments of the present invention, cleanliness
boosters may be present as 0.5-3 wt % of the total weight of the
lubricant composition. The cleanliness boosters are preferably
present as 0.5-1.5 wt % of the total weight of the lubricant
composition, and more preferably, the cleanliness boosters are
present as 1 wt % of total weight of the lubricant composition.
[0138] Antiwear
[0139] In some embodiments of the present invention, antiwear
additives may be included in the lubricant composition.
Illustrative antiwear additives useful in this disclosure include,
for example, metal salts of a carboxylic acid. The metal is
selected from a transition metal and mixtures thereof. The
carboxylic acid is selected from an aliphatic carboxylic acid, a
cycloaliphatic carboxylic acid, an aromatic carboxylic acid, and
mixtures thereof.
[0140] The metal is preferably selected from a Group 10, 11 and 12
metal, and mixtures thereof. The carboxylic acid is preferably an
aliphatic, saturated, unbranched carboxylic acid having from about
8 to about 26 carbon atoms, and mixtures thereof.
[0141] The metal is preferably selected from nickel (Ni), palladium
(Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc
(Zn), cadium (Cd), mercury (Hg), and mixtures thereof.
[0142] The carboxylic acid is preferably selected from caprylic
acid (C8), pelargonic acid (C9), capric acid (C10), undecylic acid
(C11), lauric acid (C12), tridecylic acid (C13), myristic acid
(C14), pentadecylic acid (C15), palmitic acid (C16), margaric acid
(C17), stearic acid (C18), nonadecylic acid (C19), arachidic acid
(C20), heneicosylic acid (C21), behenic acid (C22), tricosylic acid
(C23), lignoceric acid (C24), pentacosylic acid (C25), cerotic acid
(C26), and mixtures thereof.
[0143] Preferably, the metal salt of a carboxylic acid comprises
zinc stearate, silver stearate, palladium stearate, zinc palmitate,
silver palmitate, palladium palmitate, and mixtures thereof.
[0144] The metal salt of a carboxylic acid is present in the engine
oil formulations of this disclosure in an amount of from about 0.01
weight percent to about 5 weight percent, based on the total weight
of the formulated oil.
[0145] Low phosphorus engine oil formulations are included in this
disclosure. For such formulations, the phosphorus content is
typically less than about 0.12 weight percent preferably less than
about 0.10 weight percent and most preferably less than about 0.085
weight percent.
[0146] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) can be a useful component of
the lubricating oils of this disclosure. ZDDP can be derived from
primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR1)(OR2)]2
[0147] where R1 and R2 are C1-C18 alkyl groups, preferably C2-C12
alkyl groups. These alkyl groups may be straight chain or branched.
Alcohols used in the ZDDP can be 2-propanol, butanol, secondary
butanol, pentanols, hexanols such as 4-methyl-2-pentanol,
n-hexanol, n-octanol, 2-ethyl hexanol, alkylated phenols, and the
like. Mixtures of secondary alcohols or of primary and secondary
alcohol can be preferred. Alkyl aryl groups may also be used.
[0148] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 677A", "LZ 1095" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "HITEC
7169".
[0149] Low phosphorus engine oil formulations are included in this
disclosure. For such formulations, the phosphorus content is
typically less than about 0.12 weight percent preferably less than
about 0.10 weight percent and most preferably less than about 0.085
weight percent.
[0150] Antioxidants
[0151] In some embodiments of the present invention, antioxidants
may be included in the lubricant composition. Antioxidants retard
the oxidative degradation of base oils during service. Such
degradation may result in deposits on metal surfaces, the presence
of sludge, or a viscosity increase in the lubricant. One skilled in
the art knows a wide variety of oxidation inhibitors that are
useful in lubricating oil compositions. See, Klamann in Lubricants
and Related Products, op cite, and U.S. Pat. Nos. 4,798,684 and
5,084,197, for example.
[0152] Useful antioxidants include hindered phenols. These phenolic
antioxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones which contain a sterically hindered hydroxyl group, and
these include those derivatives of dihydroxy aryl compounds in
which the hydroxyl groups are in the o- or p-position to each
other. Typical phenolic antioxidants include the hindered phenols
substituted with C6+ alkyl groups and the alkylene coupled
derivatives of these hindered phenols. Examples of phenolic
materials of this type 2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl
phenol; 2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant disclosure. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2'-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0153] Effective amounts of one or more catalytic antioxidants may
also be used. The catalytic antioxidants comprise an effective
amount of a) one or more oil soluble polymetal organic compounds;
and, effective amounts of b) one or more substituted
N,N'-diaryl-o-phenylenediamine compounds or c) one or more hindered
phenol compounds; or a combination of both b) and c). Catalytic
antioxidants are more fully described in U.S. Pat. No. 8,048,833,
herein incorporated by reference in its entirety.
[0154] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R8R9R10N where R8 is an
aliphatic, aromatic or substituted aromatic group, R9 is an
aromatic or a substituted aromatic group, and R10 is H, alkyl, aryl
or R11S(O)XR12 where R11 is an alkylene, alkenylene, or aralkylene
group, R12 is a higher alkyl group, or an alkenyl, aryl, or alkaryl
group, and x is 0, 1 or 2. The aliphatic group R8 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 R8 and R9 are aromatic or substituted
aromatic groups, and the aromatic group may be a fused ring
aromatic group such as naphthyl. Aromatic groups R8 and R9 may be
joined together with other groups such as S.
[0155] Typical aromatic amines antioxidants have alkyl substituent
groups of at least about 6 carbon atoms. Examples of aliphatic
groups include hexyl, heptyl, octyl, nonyl, and decyl. Generally,
the aliphatic groups will not contain more than about 14 carbon
atoms. The general types of amine antioxidants useful in the
present compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present disclosure
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0156] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0157] Pour Point Depressants (PPDs)
[0158] In some embodiments of the present invention, conventional
pour point depressants, also known as lube oil flow improvers, may
be included in the lubricant composition. These pour point
depressants may be added to lubricating compositions of the present
disclosure to lower the minimum temperature at which the fluid will
flow or can be poured. Examples of suitable pour point depressants
include polymethacrylates, polyacrylates, polyarylamides,
condensation products of haloparaffin waxes and aromatic compounds,
vinyl carboxylate polymers, and terpolymers of dialkylfumarates,
vinyl esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof.
[0159] Seal Compatibility Agents
[0160] In certain embodiments of the present invention, seal
compatibility agents may be included in the lubricant composition.
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.
[0161] Antifoam Agents
[0162] In certain embodiments of the present invention, antifoam
agents may be included in the lubricant composition. 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.
[0163] Inhibitors and Antirust Additives
[0164] In certain embodiments of the present invention, antirust
additives may be included in the lubricant composition. Antirust
additives (or corrosion inhibitors) are additives that protect
lubricated metal surfaces against chemical attack by water or other
contaminants. A wide variety of these are commercially
available.
[0165] One type of antirust additive is a polar compound that wets
the metal surface preferentially, protecting it with a film of oil.
Another type of antirust additive absorbs water by incorporating it
in a water-in-oil emulsion so that only the oil touches the metal
surface. Yet another type of antirust additive chemically adheres
to the metal to produce a non-reactive surface. Examples of
suitable additives include zinc dithiophosphates, metal phenolates,
basic metal sulfonates, fatty acids and amines.
EXAMPLES
[0166] The following non-limiting examples are provided to
illustrate the disclosure.
Example I
[0167] A lubricant composition consistent with an embodiment of the
present invention was prepared and labeled as composition 1B. See
Table 2 below for a listing of the components of composition 1B.
For comparison, composition 1A was prepared, and a listing of the
components for composition 1A is also listed in Table 2 below.
Composition 1A is a similar composition that lacks a CRFM.
Accordingly, composition 1A lacks the complex chemical interactions
between the blend of additives and the CRFM which support the
sustained fuel economy of the lubricant composition of the present
invention.
TABLE-US-00002 TABLE 2 1A 1B wt % wt % Base stocks polyalphaolefin
33.34 31.92 Group III Base stock A 30 30 Group III Base stock B 10
10 Ester Co-base stock 5 5 Other Includes antioxidants, antiwear,
3.29 3.29 Additives pour point depressents, inorganic friction
modifiers, antifoams and seal swell agents Cleanliness Cleanliness
Booster 0 1 Booster Conventional Conventional Organic Friction 0.52
0 Organic Modifier Friction Modifier Detergents Calcium Salicylate
Detergent 3 3 Magnesium Sulfonate 0.83 0.83 Detergent Viscosity
Hydrogenated isoprene star 6.1 5.6 Modifier polymer Dispersant
Borated PIBSA/PAM dispersant 1.3 0 Succinimide Dispersant 6.62 5.4
CRFM Low-ash dispersant-stabilized 0 3.96 borated friction modifier
(high stabilizer) Summary Table CRFM None 3.96% Co-Base stock Ester
Ester Base stocks Highly Highly Paraffinic Paraffinic
[0168] Composition 1A and 1B were tested on a highly instrumented
Ford EcoBoost.RTM. GTDI 2.0 L 4-cylinder engine mounted on an
engine test stand. This test engine was a 4 valve-per-cylinder,
dual overhead camshaft engine with continuous dual variable valve
timing. The lubrication system of the engine was altered by adding
an external oil cooler at the oil filter outlet. The oil cooler was
externally fed with conditioned and temperature controlled water
that was used to maintain the oil temperature. An external coolant
conditioner was used in place of a water pump to maintain constant
consistent operating conditions. An inline torque meter was used to
calculate brake specific fuel consumption (BSFC). Fuel temperature
and pressure were strictly controlled, and a coriolis fuel flow
meter was used to measure fuel flow into the engine.
[0169] The BSFC of the engine was measured using an inline torque
meter as a function of time at five steady state operating points
spanning different engine speeds and break mean effective pressures
(BMEP). These steady state operating points corresponded to 1500
RPM and 3.0 bar BMEP, 2000 RPM and 2.0 bar BMEP, 2000 RPM and 5.0
bar BMEP, 3000 RPM and 3.0 Bar BMEP, and 4000 RPM and 5.0 bar BMEP.
Each measurement of BSFC was repeated independently at least three
times to establish statistical confidence.
[0170] Mileage accumulation was performed on the engine by
continually repeating the following one hour test cycle: 3 minutes
at 2000 RPM and 2 bar (45 mph in 4th gear), 1 minute ramp time, 20
minutes at 1700 RPM and 7.5 bar (65 mph in 6th gear), 1 minute ramp
time, 20 minutes at 1900 RPM and 8.5 bar (75 mph in 6th gear), 1
minute ramp time, 10 minutes at 1800 RPM and 8.1 bar (70 mph in 6th
gear), 1 minute ramp time, and 3 minutes at 2000 RPM and 2 bar (45
mph in 4th gear). BSFC was measured on fresh oil and after every
2500 miles of oil aging through 10,000 miles. The testing was
preformed on both composition 1A and composition 1B. The obtained
results for these tests were analyzed and compared.
[0171] Table 3 below lists the calculated percent reduction in BMEP
after 10,000 miles for composition 1A and composition 1B at the
various steady state operating points.
TABLE-US-00003 TABLE 3 % Reduction in BMEP After 10000 Miles 1A 1B
1500 rpm & 3 bar BMEP 0.37 1.09 2000 rpm & 2 bar BMEP 0.19
1.81 2000 rpm & 5 bar BMEP 0.05 0.74 3000 rpm & 3 bar BMEP
0.24 0.65 4000 rpm & 5 bar BMEP 0.71 0.62
[0172] Both compositions 1A and 1B show improved fuel consumption
after 10,000 miles at the high speed steady state operating point
of 4000 RPM and 5.0 bar BMEP. This is due to a drop in viscosity of
the oil due to fuel dilution and shear of the viscosity modifier.
Such a result would be expected, since engines at high speed
operate in the hydrodynamic regime of lubrication where surface
contact is minimal and friction modifiers are ineffective. However,
only composition 1B shows significant improvement at low speed,
where boundary and mixed regimes of lubrication occur. In these
lubrication regimes, friction modifiers can be very effective at
reducing energy loss and therefore reducing the amount of fuel
consumed for a given engine output. This effect is particularly
evident at the steady state load condition of 2000 RPM and 2.0 bar
BMEP.
[0173] The following discussion is made with reference to FIG. 1,
which illustrates the aging profile of compositions 1A and 1B for
the 2000 RPM and 2.0 bar BMEP steady state operating point from 0
through 10,000 miles. The results in FIG. 1 demonstrate the fuel
efficiency changes that result from the activation of the CRFM in
an exemplary composition of the present invention, the composition
containing a low-ash dispersant-stabilized borated controlled
release friction modifier. At the steady state load condition of
2000 RPM and 2.0 bar BMEP after 10,000 miles of aging, composition
1B shows a reduction of fuel consumption of 1.81% compared to its
fresh oil value. At this same load condition, comparative
composition 1A showed only a reduction of fuel consumption of 0.19%
compared to its fresh oil value. In other words, composition 1B,
which is consistent which an embodiment of the present invention,
under the conditions described above, demonstrated a reduction of
fuel consumption that was over nine times the amount of reduction
seen in the comparative composition. Accordingly, a composition of
an embodiment of the present invention shows significant and
sustained fuel efficiency improvements over a comparative
composition.
Example II
[0174] A lubricant composition consistent with an embodiment of the
present invention was prepared and labeled as composition 2B. See
Table 4 below for a listing of the components of composition 2B.
For comparison, composition 2A was prepared, and a listing of the
components for composition 2A also listed in Table 4. Composition
2A is a similar composition that lacks a CRFM. Accordingly,
composition 2A lacks the complex chemical interactions between the
blend of additives and the CRFM, which support the sustained fuel
economy of the lubricant composition of the present invention.
TABLE-US-00004 TABLE 4 2A 2B wt % wt % Base stocks polyalphaolefin
10 10 Group III Base stock A 53.61 52.21 Group III Base stock B 12
12 Alkylated Naphthalene 5 5 Other Additives Includes antioxidants,
antiwear, 2.96 2.96 pour point depressents, inorganic friction
modifiers, antifoams and seal swell agents Conventional
Conventional Organic Friction 0.5 0 Organic Friction Modifier
Modifier Detergents Calcium Sulfonate 1.15 1.15 Magnesium Sulfonate
0.88 0.88 Viscosity Modifier Hydrogenated isoprene star 6.2 6.4
polymer Cleanliness Cleanliness Booster 0.5 1 Booster Dispersant
Borated PIBSA/PAM dispersant 1.2 0.74 Succinimide Dispersant 6 3.7
CRFM Low-ash dispersant-stabilized 0 3.96 borated friction modifier
(high stabilizer) Summary Table CRFM None 3.96% Co-Base stock
Alkylated Alkylated Naphthalene Naphthalene Base stocks Highly
Highly Paraffinic Paraffinic
[0175] This testing was performed to demonstrate that the fuel
economy benefits shown in the instrumented engine test stand
running steady state operating points could be observed in a full
chassis dynamometer running the EPA FTP-75 test and the EPA Highway
Fuel Economy Test. Compositions 2A and 2B were tested by making
aged oil fuel economy measurements on two equivalent 2016 model
year Toyota Camrys with 3.5 L V-6 port fuel injected engines and
automatic transmissions. These two cars were purchased new and were
run for 200 miles before their use in the testing procedure. Each
car received triplicate checkout emissions measurements over the
requirements of EPA Federal Test Procedure 75 (FTP-75) and EPA
Highway Fuel Economy Test (HwFET) using 87 octane regular unleaded
gasoline to ensure the cars chosen were matched with similar
performance. All fuel economy measurements were performed on the
same Horiba 48-inch single roll chassis dynamometer. The tested
compositions were aged by removing the cars from the measurement
dynamometer and placing them on a mileage accumulation dynamometer,
where the HwFET drive cycle was run continuously with an average
speed of approximately 48 miles per hour. Then, the cars were put
back on the measurement dynamometer after every 5000 mile aging
cycle, were FTP-75 and HwFET measurements were performed to
establish vehicle fuel economy. Each set of FTP-75 and HwFET
measurements was repeated at least 3 times to establish confidence.
Minimal lubricant sampling was performed for oil analysis and no
oil top-up was conducted to maintain a steady volume. The results
of this testing were then collected and analyzed.
[0176] The following discussion is made with reference to FIG. 2,
which illustrates the fuel economy change calculated for
compositions 2A and 2B over the course of a 15,000 mile aging
cycle. Comparative composition 2B shows a decrease in fuel economy
of approximately 0.2 mpg over 15000 miles. On the other hand,
composition 2B, which is consistent with an embodiment of the
present invention, surprisingly shows an increase in fuel economy
of approximately 0.2 mpg over 15000 miles, as measured by these
test protocols. This result is unexpected because an aged oil
composition is generally expected to be less able to deliver fuel
economy than a new oil composition, which contains a full load of
friction modifier. Friction modifier is well known to be consumed
early on in oil aging. However, the dispersant stabilized borated
controlled release friction modifier of the present invention is
capable of maintaining a stable supply of friction modifier while
the oil is aging. As both oils have equivalent viscosity and are in
equivalent cars, the 0.4 mpg improvement of composition 2B over
comparative composition 2A is caused by the low-ash dispersant
stabilized borated controlled release friction modifier and its
complex chemical interaction with the components of the
composition.
[0177] 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.
* * * * *