U.S. patent application number 16/041320 was filed with the patent office on 2019-01-24 for lubricating composition with enhanced filterability.
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 | 20190024014 16/041320 |
Document ID | / |
Family ID | 65015625 |
Filed Date | 2019-01-24 |
United States Patent
Application |
20190024014 |
Kind Code |
A1 |
BLUMENFELD; Michael L. ; et
al. |
January 24, 2019 |
LUBRICATING COMPOSITION WITH ENHANCED FILTERABILITY
Abstract
A lubricating oil composition that includes a highly paraffinic
base oil, a controlled release friction modifier (CRFM) and an
effective amount of detergent. The CRFM includes an ionic
tetrahedral borate compound comprising a cation and a tetrahedral
borate anion which includes a boron atom, the boron atom having two
bidentate di-oxo ligands of C.sub.18 tartrimide. The CRFM is a high
stabilizer CRFM. The detergent includes a mixed magnesium and
calcium detergent system having a calcium to magnesium ratio of
less than 2:1.
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: |
65015625 |
Appl. No.: |
16/041320 |
Filed: |
July 20, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62535547 |
Jul 21, 2017 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 169/04 20130101;
C10M 159/18 20130101; C10N 2020/02 20130101; C10M 2201/084
20130101; C10M 2203/1025 20130101; C10M 2207/09 20130101; C10M
2227/061 20130101; C10N 2060/14 20130101; C10N 2020/04 20130101;
C10M 2205/163 20130101; C10N 2010/04 20130101; C10M 2205/08
20130101; C10N 2030/06 20130101; C10N 2040/25 20130101; C10M
2207/028 20130101; C10M 2217/06 20130101; C10N 2030/04 20130101;
C10M 2215/28 20130101; C10M 2219/046 20130101; C10N 2030/52
20200501; C10M 2205/0285 20130101; C10M 159/24 20130101; C10M
2217/024 20130101; C10M 2215/086 20130101; C10M 2207/262
20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04; C10M 159/18 20060101 C10M159/18; C10M 159/24 20060101
C10M159/24 |
Claims
1. A lubricating oil composition, comprising: a base oil comprising
a highly paraffinic base oil; 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
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, and
a second dispersant comprising an ammonium substituted
polyisobutenyl succinimde compound having an N:CO ratio of 1.8 and
a polyisobutylenyl number average molecular weight of 750 to 2,500;
and an effective amount of a detergent.
2. The lubricating oil composition of claim 1, wherein the
detergent comprises a mixed magnesium and calcium detergent
system.
3. The lubricating oil composition of claim 2, wherein the mixed
magnesium and calcium detergent system has a ratio of calcium to
magnesium of less than 2:1.
4. The lubricating oil composition of claim 2, wherein the mixed
magnesium and calcium detergent system has a calcium:magnesium
ratio of 1.44:1.
5. The lubricating oil composition of claim 1, wherein the CRFM is
a high stabilizer CRFM.
6. The lubricating oil composition of claim 2, wherein the CRFM is
a high stabilizer CRFM.
7. The lubricating oil composition of claim 1, wherein the CRFM is
present in a range of about 2 to 8 wt %, based on the total weight
of the composition.
8. The lubricating oil composition of claim 1, wherein nitrogen in
the CRFM derived from the tartrimide is present in the range of
about 35% to 55 wt %, based on the total nitrogen content of the
CRFM.
9. The lubricating oil composition of claim 1, wherein the
detergent is selected from the group consisting of: overbased
calcium salicylate detergent, low base calcium salicylate
detergent, neutral calcium sulfonate detergent, overbased calcium
sulfonate detergent and overbased magnesium sulfonate
detergent.
10. The lubricating oil composition of claim 1, wherein the
detergent is present in the range of about 1 to 10 wt %, based on
the total weight of the composition.
11. The lubricating oil composition of claim 1, wherein the base
oil comprises a Group III basestock and a polyalphaolefin (PAO)
basestock.
12. The lubricating oil composition of claim 11, wherein the Group
III basestock is present in a range of about 10 to about 90 wt %
and the polyalphaolefin (PAO) basestock is present in a range of
about 0 to about 60 wt %, based on the total weight of the
composition.
13. A lubricating oil composition, comprising: a base oil
comprising a highly paraffinic base oil; a high stabilizer
controlled release friction modifier (CRFM), 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, and a second dispersant
comprising an ammonium substituted polyisobutenyl succinimde
compound having an N:CO ratio of 1.8 and a polyisobutylenyl number
average molecular weight of 750 to 2,500; and an effective amount
of a mixed magnesium and calcium detergent system.
14. The lubricating oil composition of claim 13, wherein the mixed
magnesium and calcium detergent system has a ratio of calcium to
magnesium of less than 2:1.
15. The lubricating oil composition of claim 13, wherein the mixed
magnesium and calcium detergent system has a calcium:magnesium
ratio of 1.44:1.
16. A lubricating oil composition, comprising: a highly paraffinic
base oil; 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 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, and a second dispersant
comprising an ammonium substituted polyisobutenyl succinimde
compound having an N:CO ratio of 1.8 and a polyisobutylenyl number
average molecular weight of 750 to 2,500; and an effective amount
of a mixed magnesium and calcium detergent system having a
calcium:magnesium ratio of less than 2:1.
Description
[0001] This nonprovisional application claims priority to U.S.
Provisional Application No. 62/535,547, which was filed on Jul. 21,
2017, and is herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to lubricating compositions,
in particular to a lubricating composition having a highly
paraffinic basestock with improved filterability performance.
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 a challenging endeavor.
[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 enhanced filterability.
[0007] Further, in the case of some lubricant compositions, the
additives used in lubricant compositions may participate in the
formation of needle crystals which may cause clogging of oil
filters. The influences of various conditions and combinations of
lubricant additives have been studied. It has been shown that
needle crystals form when the lubricant composition includes a
magnesium-based detergent. When a magnesium-based detergent comes
into contact with water and carbonic acid gas the needle crystals
form.
[0008] Furthermore, 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 the 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.
[0009] It is therefore advantageous to develop formulations with
controlled release friction modifiers (CRFM) 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 CRFM
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.
[0010] However, CRFM 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
[0011] Moreover, the highest performance lubricants usually entail
the use of base oils that are highly paraffinic. Such base oils
would include API Group IV polyalphaolefins (PAO), API Group III's
such as gas-to-liquids (GTL) base oils and potentially even highly
saturated Group II base oils. Such oils are highly non-polar and as
a result have a limited amount of solubility for polar
additives.
[0012] 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.
[0013] Accordingly, there exists a need for improved lubricant
compositions capable of providing enhanced filterability while
meeting all of the requirements for the use of a lubricant
composition in an engine.
SUMMARY OF THE INVENTION
[0014] In view of the forgoing of other exemplary problems,
drawbacks and disadvantages of the conventional methods and
compositions, an exemplary feature of the present invention is to
provide a lubricating composition containing a CRFM in a highly
paraffinic basestock while maintaining strong filterability
performance.
[0015] Exemplary embodiments of the invention are directed to a
lubricating oil composition that includes a highly paraffinic base
oil. In an embodiment of the invention, the base oil is a blend of
a Group III base oil and a polyalphaolefin base oil.
[0016] The composition further includes a CRFM and an effective
amount of at least one additive. According to an embodiment of the
invention, the CRFM is an ashless CRFM including a
dispersant-stabilized, borated CRFM comprising an ionic tetrahedral
borate compound including a tetrahedral borate anion having a boron
atom with two bidentate di-oxo ligands both being a linear
C18-tartrimide, a first dispersant comprising a conventional
ammonium substituted polyisobutenyl succinimide compound having a
polyisobutenyl number average molecular weight of 750 to 2,500, a
second dispersant comprising an ammonium substituted polyisobutenyl
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 (referred to herein as a
"dispersant-stabilized borated CRFM")
[0017] Further, the lubricating oil composition includes an
effective amount of a detergent that provides for improved levels
of filterability as compared to the levels achieved when the
lubricating oil composition does not include the CRFM.
Specifically, in accordance with certain exemplary aspects of the
invention, the detergent is a mixed calcium and magnesium detergent
system, preferably with a ratio of calcium to magnesium of less
than 2.
DETAILED DESCRIPTION
[0018] 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.
[0019] 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.
[0020] 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.
[0021] The present invention is directed to a lubricating oil
composition that includes a base oil. The composition further
includes a CRFM and an effective amount of at least one additive.
The effective amount of an additive is the sufficient amount to
provide for improved levels of filterability as compares to the
levels achieved when the lubricating oil composition does not
include the CRFM. The additive may be selected from the group of
inorganic friction modifiers, dispersants, detergents, viscosity
modifiers and cleanliness boosters.
[0022] CRFMs are highly advantageous due to their ability to reduce
friction over long oil drain intervals. Friction reduction is
important in improving fuel economy. However, it is well known that
CRFMs often pose filterability issues. In order to be efficacious,
friction modifiers generally have limited oil solubility in order
to provide a high affinity for metallic surfaces in the engine.
This low solubility poses filtration problems, particularly when an
oil is at low temperatures or mixed with water and other
contaminants. In controlled release friction modifiers, friction
modifier molecules are used above their solubility limit, creating
even greater potential for filterability issues.
[0023] Acceptable filterability is particularly challenging to
achieve in highly paraffinic basestocks such as those used here.
The present disclosure shows a surprising improvement of the
compatibility of CRFMs by using a combination of high dispersant
stabilizer and magnesium based detergents. This is particularly
surprising as it is well known in the industry that magnesium based
detergents are detrimental to filterability, and therefore would
not be anticipated as a solution to a filterability issue.
[0024] In order to measure filterability of a composition the
standardized ASTM D6795 is generally used. ASTM D6795 standard
method measures the effects on filterability of engine oils after
treatment with water and dry ice and a short (30 min) heating time.
This standardized test is part of ILSAC (International Lubricants
Specification Advisory Committee) and the American Petroleum
Institute (API) S engine oil specifications.
[0025] The key rating of the ASTM D6795 involves the change in flow
rate of a lubricating oil as it is passed through a filter. A
lubricant that does not flow through the filter is reported as
"clogged." This is a failing result.
[0026] Controlled Release Friction Modifier (CRFM)
[0027] 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.
[0028] 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
succinimde compound having an N:CO ratio of 1.8 and a
polyisobutylenyl number average molecular weight of 750 to 2,500,
wherein one or more of the first dispersant and the second
dispersant are converted to a cationic form.
[0029] The above described ionic tetrahedral borate compound can
serve as a friction modifier, in a lubricating composition.
[0030] In one embodiment, the structure of the tetrahedral borate
ion of the tetrahedral borate compound may be represented by the
structure shown in Formula I:
##STR00001##
where R3, R4 form a 5 membered nitrogen-containing heterocyclic
ring substituted with a linear C18 group.
[0031] 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.
[0032] 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").
[0033] 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).
[0034] 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.
[0035] 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 I-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.
[0036] 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.
[0037] In an embodiment, the ionic borate compound is the reaction
product of a tartrimide, a borate ester, and at least one basic
component, such as two dispersants, to form a "boro-tartrimide"
friction modifier. The ionic boron compound described herein is
used to improve friction.
[0038] A problem with conventional friction modifiers, as noted
above, is that the friction modifier is not sufficiently soluble,
which leads to an insufficient amount of friction modifier being
available during consumption of the lubricating oil and sludge
(i.e., deposits) may form. The CRFM in accordance with certain
exemplary embodiments of the present invention maintains sufficient
friction modifier at the surface to provide lower friction
lubricating oils while improving overall fuel economy. That is, the
CRFM described herein raises the amount of friction modifier by
using a tetra-valent boron chemistry to complex the friction
modifier. This results in a much larger amount of friction modifier
in the lubricating oil with resulting improvements to fuel economy.
Also, it is know that ash can damage the particulate filter of an
engine. High ash compositions (i.e., compositions with high amounts
of detergent) are not desirable. The present CRFM is preferably a
low ash CRFM.
[0039] 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 CRFM is provided in an amount of 3.96 wt %.
[0040] Further, in an embodiment, the CRFM comprises an amount of
nitrogen contributed from the tartrimide from about 35 to about 55
weight percent, based on the total weight percent of the CRFM.
Nitrogen from the tartrimide is preferably present in the CRFM in
amount from about 40 to about 50 weight percent, based on the total
weight percent of the CRFM. Even more preferably, nitrogen from the
tartrimide is present in the CRFM in an amount from about 43 to
about 47 weight percent, based on the total weight percent of the
CRFM.
[0041] Base Oil Stocks
[0042] 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.
[0043] 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 0.03% sulfur and greater than
90% saturates. Group IV includes polyalphaolefins (PAO). Group V
base stock includes base stocks not included in Groups I-IV. The
table below summarizes properties of each of these five groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I <90 and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV
polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III or IV
[0044] 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.
[0045] 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.
[0046] 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.
[0047] The hydrocarbyl aromatics can be used as base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least about 5% of its weight derived from an aromatic moiety such
as a benzenoid moiety or naphthenoid moiety, or their derivatives.
These hydrocarbyl aromatics include alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and the like. The aromatics can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can also be comprised
of mixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl
groups, cycloalkenyl groups and other related hydrocarbyl groups.
The hydrocarbyl groups can range from about C6 up to about C60 with
a range of about C8 to about C40 often being preferred. A mixture
of hydrocarbyl groups is often preferred. The hydrocarbyl group can
optionally contain sulfur, oxygen, and/or nitrogen containing
substituents. The aromatic group can also be derived from natural
(petroleum) sources, provided at least about 5% of the molecule is
comprised of an above-type aromatic moiety. Viscosities at
100.degree. C. of approximately 3 cSt to about 50 cSt are
preferred, with viscosities of approximately 3.4 cSt to about 20
cSt often being more preferred for the hydrocarbyl aromatic
component. Naphthalene or methyl naphthalene, for example, can be
alkylated with olefins such as octene, decene, dodecene,
tetradecene or higher, mixtures of similar olefins, and the like.
Useful concentrations of hydrocarbyl aromatic in a lubricant oil
composition can be about 2% to about 25%, preferably about 4% to
about 20%, and more preferably about 4% to about 15%, depending on
the application.
[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, 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 acids, lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures of any of these materials.
[0050] Non-conventional or unconventional base stocks and/or base
oils include one or a mixture of base stock(s) and/or base oil(s)
derived from: (1) one or more Gas-to-Liquids (GTL) materials, as
well as (2) hydrodewaxed, or hydroisomerized/cat (and/or solvent)
dewaxed base stock(s) and/or base oils derived from synthetic wax,
natural wax or waxy feeds, mineral and/or non-mineral oil waxy feed
stocks such as gas oils, slack waxes (derived from the solvent
dewaxing of natural oils, mineral oils or synthetic oils; e.g.,
Fischer-Tropsch feed stocks), natural waxes, and waxy stocks such
as gas oils, waxy fuels hydrocracker bottoms, waxy raffinate,
hydrocrackate, thermal crackates, foots oil or other mineral,
mineral oil, or even non-petroleum oil derived waxy materials such
as waxy materials recovered from coal liquefaction or shale oil,
linear or branched hydrocarbyl compounds with carbon number of
about 20 or greater, preferably about 30 or greater and mixtures of
such base stocks and/or base oils.
[0051] 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.
[0052] 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).
[0053] 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.
[0054] 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.
[0055] The GTL material, from which the GTL base stock and/or base
oil is/are derived, is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0056] Base oils for use in the formulated lubricating oils useful
in the present invention are any of the variety of oils
corresponding to API Group I, Group II, Group III, Group IV, Group
V and Group VI oils and mixtures thereof, preferably API Group III,
Group IV, and Group V oils and mixtures thereof, more preferably
the Group III to Group VI base oils due to their exceptional
volatility, stability, viscometric and cleanliness features. Minor
quantities of Group I stock, such as the amount used to dilute
additives for blending into formulated lube oil products, can be
tolerated but should be kept to a minimum, i.e. amounts only
associated with their use as diluent/carrier oil for additives used
on an "as-received" basis. Even in regard to the Group II stocks,
it is preferred that the Group II stock be in the higher quality
range associated with that stock, i.e. a Group II stock having a
viscosity index in the range 100<VI<120.
[0057] In an embodiment, the lubricating oil composition includes
the base oil comprising the Group III oil from about 10 to about 90
weight percent, based on the total weight percent of the
composition. The Group III oil is preferably present in the base
oil in an amount from about 30 to about 70 weight percent, based on
the total weight percent of the composition. Even more preferably,
the Group III oil is present in an amount from about 40 to 64.21
weight percent, based on the total weight percent of the
composition.
[0058] Additionally, the base oil also may contain polyalphaolefin
oil basestocks (the Group IV oil) up to about 60 weight percent,
based on the total weight percent of the composition. The Group IV
oil is preferably present in an amount from about 5 to about 50
weight percent, based on the total weight percent of the
composition. Even more preferably, the Group IV oil is present in
an amount from about 10 to about 31.99 weight percent, based on the
total weight percent of the composition.
[0059] Even further, the base oil may also comprise a Group V oil
chosen from ester and alkylated naphthalene in an amount up to
about 15 weight percent, based on the total weight percent of the
composition. The Group V oil is preferably present in an amount up
to about 10 weight percent, based on the total weight percent of
the composition. Even more preferably, the Group V oil is present
in an amount about 5 weight percent, based on the total weight
percent of the composition.
[0060] Additives
[0061] The lubricating oil composition according to the present
disclosure additionally contains one or more of commonly used
lubricating oil performance additives including but 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, and others. For a
review of many commonly used additives, see Klamann in Lubricants
and Related Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN
0-89573-177-0. Reference is also made to "Lubricant Additives" by
M. W. Ranney, published by Noyes Data Corporation of Parkridge, N J
(1973); see also U.S. Pat. No. 7,704,930, the disclosure of which
is incorporated herein in its entirety. These additives are
commonly delivered with varying amounts of diluent oil that may
range from 5 weight percent to 50 weight percent.
[0062] The types and quantities of performance additives used in
combination with the instant disclosure in the lubricating oil
composition are not limited by the examples shown herein as
illustrations.
[0063] Detergents
[0064] 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.
[0065] 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.
[0066] The metal is selected from, for example, an alkali metal, an
alkaline earth metal, and mixtures thereof. More preferably, the
metal is selected from calcium (Ca), magnesium (Mg), and mixtures
thereof.
[0067] The organic acid or inorganic acid is preferably selected
from a sulfur acid, a carboxylic acid, a phosphorus acid, and
mixtures thereof.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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##
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.
[0072] 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.
[0073] Alkaline earth metal phosphates can also be used as
detergents.
[0074] 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.
[0075] Preferred detergents include calcium sulfonates, magnesium
sulfonates, calcium salicylates, magnesium salicylates, calcium
phenates, magnesium phenates, and other related components
(including borated detergents), and mixtures thereof. Preferred
mixtures of detergents include magnesium sulfonate and calcium
salicylate, magnesium sulfonate and calcium sulfonate, magnesium
sulfonate and calcium phenate, calcium phenate and calcium
salicylate, calcium phenate and calcium sulfonate, calcium phenate
and magnesium salicylate, calcium phenate and magnesium phenate.
Overbased detergents are also preferred.
[0076] Even more preferred detergents include overbased calcium
salicylate detergent, low base calcium salicylate detergent,
neutral calcium sulfonate detergent, overbased calcium sulfonate
detergent and overbased magnesium sulfonate detergent.
[0077] The detergent concentration in the lubricating oil
composition of this disclosure can range from about 1 to about 10
weight percent, preferably about 1 to 5 weight percent, and more
preferably from about 2.03 weight percent to about 3.83 weight
percent, based on the total weight of the lubricating oil
composition.
[0078] More specifically, the lubricating oil composition of this
disclosure preferably contains about 3.0 weight percent of calcium
salicylate detergent and about 0.83 percent of magnesium sulfonate
detergent, based on the total weight of the composition.
[0079] Alternatively, the lubricating oil composition of this
disclosure may contain 1.15 weight percent of calcium sulfonate
detergent and about 0.88 weight percent of magnesium sulfonate
detergent.
[0080] Further, the detergent of the lubricating oil composition of
this disclosure can have calcium (Ca) to magnesium (Mg) ration from
about 0.25 to about 10, preferably about 0.5 to 3, and more
preferably from about 1.2-1.58.
[0081] 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.
[0082] Dispersants
[0083] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
used in the formulation of the lubricating oil may be ashless or
ash-forming in nature. Preferably, the dispersant is ashless. So
called ashless dispersants are organic materials that form
substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0084] 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.
[0085] 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.
[0086] 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.
[0087] 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.
[0088] 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.
[0089] 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.
[0090] 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.
[0091] 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.
[0092] 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.
[0093] 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.
[0094] 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.
[0095] 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.
[0096] 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))
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).
[0097] 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.
[0098] 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).
[0099] 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.
[0100] 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.dbd.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.
[0101] 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.
[0102] 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.
[0103] 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.
[0104] Such dispersants may be used in accordance with the present
disclosure in an amount of about 1 to 15 weight percent, preferably
about 2 to 12 weight percent, or more preferably 5.4 to 9.8 weight
percent, based on the total weight of the composition. These
dispersants may contain both neutral and basic nitrogen, and
mixtures of both. Dispersants can be end-capped by borates and/or
cyclic carbonates.
[0105] More specifically, in accordance with the present
disclosure, Borated Succinimide Dispersant B may be used in an
amount about 0.74 weight percent, in combination with Succinimide
Dispersant B in an amount about 3.7 weight percent, based on the
total weight of the composition.
[0106] Ethylene Capped Succinimide Dispersant may be present in an
amount about 7.35 weight percent, based on the total weight of the
composition.
[0107] Succinimide Dispersant B may be present in an amount about
5.4 weight percent, based on the total weight of the
composition.
[0108] Borated polyaolefin amide alkeneamine dispersant may be
present in an amount about 8.75 weight percent, based on the total
weight of the composition.
[0109] Succinimide Dispersant A may be present in an amount about
6.13 weight percent, based on the total weight of the
composition.
[0110] Viscosity Modifiers
[0111] Viscosity modifiers (also known as viscosity index improvers
(VI improvers), and viscosity improvers) can be included in the
lubricant compositions of this disclosure.
[0112] Viscosity modifiers provide lubricants with high and low
temperature operability. These additives impart shear stability at
elevated temperatures and acceptable viscosity at low
temperatures.
[0113] 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.
[0114] 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.
[0115] 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. 58506"; 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 150".
[0116] 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).
[0117] Illustrative vinyl aromatic-containing polymers useful in
this disclosure may be derived predominantly from vinyl aromatic
hydrocarbon monomer. Illustrative vinyl aromatic-containing
copolymers useful in this disclosure may be represented by the
following general formula:
A-B
wherein A is a polymeric block derived predominantly from vinyl
aromatic hydrocarbon monomer, and B is a polymeric block derived
predominantly from conjugated diene monomer.
[0118] In certain preferred embodiments of the present invention,
the viscosity modifier is a hydrogenated star polymer. In an
embodiment of this disclosure, the viscosity modifiers may be used
in an amount from about 1 to about 15 weight percent, preferably in
an amount from about 1 to about 8 weight percent weight percent,
and more preferably in an amount from about 1.8 to about 6.4 weight
percent, based on the total weight of the composition. Viscosity
modifiers are typically added as concentrates, in large amounts of
diluent oil.
[0119] Antioxidants
[0120] 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.
[0121] 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).
[0122] 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.
[0123] 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.
[0124] 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.
[0125] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0126] Preferred antioxidants include hindered phenols, arylamines.
These antioxidants may be used individually by type or in
combination with one another.
[0127] Pour Point Depressants (PPDs)
[0128] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
disclosure if desired. These pour point depressant may be added to
lubricating compositions of the present disclosure to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof.
[0129] Antifoam Agents
[0130] Anti-foam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical anti-foam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Anti-foam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers.
[0131] Additional Friction Modifiers
[0132] A friction modifier is any material or materials that can
alter the coefficient of friction of a surface lubricated by any
lubricant or fluid containing such material(s). Friction modifiers,
also known as friction reducers, or lubricity agents or oiliness
agents, and other such agents that change the ability of base oils,
formulated lubricant compositions, or functional fluids, to modify
the coefficient of friction of a lubricated surface may be
effectively used in combination with the base oils or lubricant
compositions of the present disclosure if desired. Friction
modifiers that lower the coefficient of friction are particularly
advantageous in combination with the base oils and lube
compositions of this disclosure.
[0133] Illustrative additional 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.
[0134] 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.
[0135] 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.
[0136] 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.
[0137] 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.
[0138] 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.
[0139] 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.
[0140] The lubricating oils of this disclosure exhibit desired
properties, e.g., wear control, in the presence or absence of a
friction modifier.
[0141] Antiwear Additives
[0142] 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.
[0143] 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.
[0144] 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.
[0145] 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.
[0146] Preferably, the metal salt of a carboxylic acid comprises
zinc stearate, silver stearate, palladium stearate, zinc palmitate,
silver palmitate, palladium palmitate, and mixtures thereof.
[0147] 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.
[0148] 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.
[0149] 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
[0150] 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.
[0151] 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".
[0152] Cleanliness Booster
[0153] 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 and gasoline
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.
[0154] 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.
[0155] 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 specifications.
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.
[0156] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 1 below.
[0157] 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. The
weight percent (wt %) indicated below is based on the total weight
of the lubricating oil composition.
Examples and Comparative Examples
[0158] The following examples are non-limiting in nature and are
provided to more particularly illustrate the disclosure.
[0159] ASTM D6795 Test
[0160] An ASTM D6795 test was performed. ASTM D6795 is a standard
method for measuring the effect on filterability of engine oils
after treatment with water and dry ice and a short (30 min) heating
time. Specifically, the test oil is treated with 0.6% deionized
water and dry ice. The sample is heated to 70.degree. C. for 30
min, followed by storage at room temperature for 48 hours. The
sample is filtered and the flow rate is calculated and compared to
the flow rate of a sample of the engine oil that was not treated
with water and dry ice. The change in flow rate provides a measure
of the engine oil filterability characteristics. This standard is
part of the ILSAC GF-x (x=1, 2, 3, 4, or 5) and API S engine oil
specifications.
Example I
[0161] A comparative lubricant composition labeled 1A is a typical
all-calcium detergent package that shows no challenges in
filterability but contains only a standard friction modifier,
rather than the CRFM.
[0162] Compositions 1B, 1C and 1D contain additionally the low
stabilizer CRFM consisting of about 43 percent weight of nitrogen
from a dispersant and about 57 percent weight of nitrogen from the
tartrimide. The filterability as measured by ASTM D6795 has failed
in all three compositions.
[0163] The low stabilizer CRFM of the compositions 1B, 1C and 1D
has been subsisted by high stabilizer CRFM in composition 1 E in
order to improve the performance of this formulation. High
stabilizer CRFM consists of about 55 percent weight of nitrogen
from stabilizing dispersants and about 45 percent weight of
nitrogen from the tartrimide as illustrated below in Table 2. While
minor improvement through the use of a high stabilizer CRFM is
evident, composition 1 E also failed the ASTM D6795 test as set
forth below in Table 2. High stabilizer and low stabilizer CRFM are
distinguished by the amount of nitrogen provided by the active
friction modifier portion of the CRFM system and the amount of
nitrogen contributed by e.g. the succinimide-derived conjugate. In
a high stabilizer version of the CRFM the tartrimide provides lower
nitrogen content than the nitrogen content provided by the friction
modifier. In a low stabilizer CRFM the nitrogen content provided by
the tartrimide is greater than the nitrogen provided by the e.g.
succinimide-derived conjugate.
TABLE-US-00002 TABLE 1 Low-ash dispersant-stabilized borated
friction modifier Description Low Stabilizer High Stabilizer
Percent (%) Nitrogen from 43 55 Dispersant Percent (%) Nitrogen
from 57 45 Tartrimide
TABLE-US-00003 TABLE 2 1A 1B 1C 1D 1E (wt %) (wt %) (wt %) (wt %)
(wt %) Basestocks Polyalphaolefin 33.14 32.58 31.6 32.08 32.41
Group III Basestock A 10 10 9.85 10 9.95 Group III Basestock B 30
30 29.55 30 29.85 Ester Co-basestock 5 5 4.92 5 4.97 Alkylated
Naphthalene Co-basestock Other Additives Inorganic Friction
Modifiers, Pour 3.29 3.29 4.74 3.29 3.28 Point Depressants,
Cleanliness Boosters, antifoams, Antiwear and antioxidants
Detergents Calcium Salicylate Detergent 5 5 4.92 5 4.97 Calcium
Sulfonate Detergent Magnesium Sulfonate Detergent Viscosity
Modifier hydrogenated isoprene star polymer 8.5 7.75 8.13 8.25 7.71
Dispersant Borated Succinimide Dispersant A 1.3 0.26 0.26 0.26 0.26
Borated Succinimide Dispersant B Succinimide Dispersant A 3.25 2.65
2.61 2.65 2.64 Borated Polyolefin Amide Alkeneamine Dispersant
Succinimide Dispersant B Ethylene Capped Succinimide Dispersant
Polyolefin Amide Alkeneamine Dispersant Conventional Friction
Conventional Organic Friction 0.52 Modifier Modifier CRFM Low-ash
dispersant-stabilized 3.47 3.42 3.47 borated friction modifier (low
stabilizer) Low-ash dispersant-stabilized 3.96 borated friction
modifier (high stabilizer) ASTM D6795 Filterability Test Result
-8.12 Plugged Plugged Plugged Plugged Pass Fail Fail Fail Fail,
-21.09 Borderline Pass Summary Table CRFM None Low- Low- Low- Low-
Stabilizer Stabilizer Stabilizer Stabilizer Detergent System
Calcium Calcium Calcium Calcium Calcium Calcium Concentration by
ASTM 2130 2270 2240 2160 2270 D5185 (ppm) Magnesium Concentration
by ASTM 6 7 6 10 7 D5185 (ppm) Calcium:Magnesium Ratio 355 324 373
216 324
Example II
[0164] Surprisingly, in example compositions 1F, 1G, 1H, 1I and 1J
by moving to a mixed magnesium and calcium detergent system with a
ratio of calcium to magnesium of less than 2:1, these compositions
have been shown to pass the ASTM D6795 test as evidenced by the
results set forth in Table 3. This test has been shown to be
insensitive to the dispersant as demonstrated. More specifically,
the exemplary composition 1K provide both controlled release
friction modification and exceptional filterability as shown in
Table 3 set forth below. Specifically, in accordance with an
exemplary preferred embodiment of the invention, example 1K is a
formulation that contains a mixed magnesium and calcium detergent
system with a calcium:magnesium ratio of 1.44:1 in addition to a
high stabilizer CRFM. This formulation provides both controlled
release friction modification and exceptional filterability.
TABLE-US-00004 TABLE 3 1F 1G 1H 1I 1J 1K (wt %) (wt %) (wt %) (wt
%) (wt %) (wt %) Basestocks Polyalphaolefin 30.57 31.92 30.72 31.99
31.37 10 Group III Basestock A 10 10 10 10 10 52.21 Group III
Basestock B 30 30 30 30 30 12 Ester Co-basestock 5 5 5 5 5
Alkylated Naphthalene Co-basestock 5 Other Inorganic Friction
Modifiers, Pour Point 4.29 4.29 4.29 4.29 4.29 3.96 Additives
Depressants, Cleanliness Boosters, antifoams, Antiwear and
antioxidants Detergents Calcium Salicylate Detergent 3 3 3 3 3
Calcium Sulfonate Detergent 1.15 Magnesium Sulfonate Detergent 0.83
0.83 0.83 0.83 0.83 0.88 Viscosity hydrogenated isoprene star
polymer 5 5.6 3.45 4.8 1.75 6.4 Modifier Dispersant Borated
Succinimide Dispersant A Borated Succinimide Dispersant B 0.74
Succinimide Dispersant A 6.13 Borated Polyolefin Amide Alkeneamine
8.75 Dispersant Succinimide Dispersant B 5.4 3.7 Ethylene Capped
Succinimide Dispersant 7.35 Polyolefin Amide Alkeneamine Dispersant
9.8 Conventional Conventional Organic Friction Modifier Friction
Modifier CRFM Low-ash dispersant-stabilized borated friction
modifier (low stabilizer) Low-ash dispersant-stabilized borated
3.96 3.96 3.96 3.96 3.96 3.96 friction modifier (high stabilizer)
ASTM D6795 Filterability Test Result -3.6 Pass -2.6 Pass -2.9 -3.2
-20.9 -4.4 Pass Pass Borderline Pass Pass Summary Table CRFM High-
High- High- High- High- High- Stabilizer Stabilizer Stabilizer
Stabilizer Stabilizer Stabilizer Detergent System Mg/Ca Mg/Ca Mg/Ca
Mg/Ca Mg/Ca Mg/Ca Calcium Concentration by ASTM D5185 (ppm) 1240
1220 1210 1220 1210 1220 Magnesium Concentration by ATSM D5185 1020
1020 1000 975 975 975 (ppm) Calcium:Magnesium Ratio 1.22 1.2 1.21
1.25 1.58 1.44
[0165] While the foregoing disclosure shows illustrative
embodiments of the invention, it should be noted that various
changes and modifications could be made herein without departing
from the scope of the invention as defined by the appended claims.
The functions, steps and/or actions of the method claims in
accordance with the embodiments of the invention described herein
need not be performed in any particular order. Furthermore,
although elements of the invention may be described or claimed in
the singular, the plural is contemplated unless limitation to the
singular is explicitly stated.
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