U.S. patent application number 14/488347 was filed with the patent office on 2015-03-26 for fuel economy engine oil composition.
This patent application is currently assigned to CHEVRON JAPAN LTD.. The applicant listed for this patent is Nobuo Ushioda. Invention is credited to Nobuo Ushioda.
Application Number | 20150087567 14/488347 |
Document ID | / |
Family ID | 51627946 |
Filed Date | 2015-03-26 |
United States Patent
Application |
20150087567 |
Kind Code |
A1 |
Ushioda; Nobuo |
March 26, 2015 |
FUEL ECONOMY ENGINE OIL COMPOSITION
Abstract
The present invention is directed to a lubricating oil additive
containing a vicinal diol and a particular detergent blend
typically is low viscosity base oils whereby exhibiting improved
fuel economy. In this respect, disclosed is a lubricating oil
composition comprising: a major amount of base oil of lubricating
viscosity; a friction modifier which is selected from the group
consisting of C.sub.10-C.sub.30 alkane 1,2-diols and
C.sub.10-C.sub.30 alkene 1,2-diols; an overbased alkyl alkaline
earth metal hydroxybenzoate detergent having a metal ratio less
than 3.0; and an overbased alkyl calcium sulfonate or an overbased
alkyl calcium hydroxybenzoate having a metal ratio of 3.5 or
greater.
Inventors: |
Ushioda; Nobuo; (Omaezaki
City, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ushioda; Nobuo |
Omaezaki City |
|
JP |
|
|
Assignee: |
CHEVRON JAPAN LTD.
Minato-ku
JP
|
Family ID: |
51627946 |
Appl. No.: |
14/488347 |
Filed: |
September 17, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61881249 |
Sep 23, 2013 |
|
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Current U.S.
Class: |
508/198 |
Current CPC
Class: |
C10M 133/12 20130101;
C10M 141/10 20130101; C10M 2219/046 20130101; C10M 2207/289
20130101; C10M 2203/1006 20130101; C10M 101/02 20130101; C10M
2215/28 20130101; C10N 2030/02 20130101; C10N 2020/019 20200501;
C10M 2203/1025 20130101; C10M 2215/223 20130101; C10M 2207/022
20130101; C10M 129/08 20130101; C10M 137/10 20130101; C10N 2020/02
20130101; C10M 135/10 20130101; C10N 2040/25 20130101; C10M
2209/084 20130101; C10M 2223/045 20130101; C10N 2030/68 20200501;
C10M 2215/064 20130101; C10M 133/44 20130101; C10M 2207/026
20130101; C10M 141/08 20130101; C10N 2030/54 20200501; C10N 2030/06
20130101; C10M 2207/262 20130101; C10N 2040/10 20130101; C10M
129/54 20130101; C10M 163/00 20130101; C10M 2215/08 20130101; C10N
2030/40 20200501; C10M 2207/262 20130101; C10N 2010/04 20130101;
C10M 2219/046 20130101; C10N 2010/04 20130101; C10M 2207/262
20130101; C10M 2207/262 20130101; C10M 2223/045 20130101; C10N
2010/04 20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101;
C10M 2207/289 20130101; C10N 2060/14 20130101; C10M 2215/08
20130101; C10M 2227/09 20130101; C10N 2010/12 20130101; C10M
2207/262 20130101; C10M 2215/08 20130101; C10M 2227/09 20130101;
C10N 2010/12 20130101; C10N 2010/12 20130101; C10M 2203/1025
20130101; C10M 2219/046 20130101; C10N 2010/12 20130101; C10N
2020/02 20130101; C10M 2223/045 20130101; C10M 2207/262 20130101;
C10N 2010/12 20130101; C10N 2010/04 20130101; C10M 2215/08
20130101; C10M 2219/046 20130101; C10M 2227/09 20130101; C10N
2010/04 20130101; C10N 2010/04 20130101; C10M 2223/045 20130101;
C10N 2010/04 20130101; C10M 2207/289 20130101; C10N 2060/14
20130101 |
Class at
Publication: |
508/198 |
International
Class: |
C10M 141/08 20060101
C10M141/08 |
Claims
1. A lubricating oil composition comprising: a. a major amount of
base oil of lubricating viscosity; b. a friction modifier which is
selected from the group consisting of C.sub.10-C.sub.30 alkane
1,2-diols and C.sub.10-C.sub.30 alkene 1,2-diols; c. an overbased
alkyl alkaline earth metal hydroxybenzoate detergent having a metal
ratio less than 3.0; and d. an overbased alkyl calcium sulfonate or
an overbased alkyl calcium hydroxybenzoate having a metal ratio of
3.5 or greater.
2. The lubricating oil composition according to claim 1, wherein
the friction modifier is selected from the formula
R.sub.1--CH(OH)CH.sub.2(OH) wherein R.sub.1 is alkyl containing
from 8 to 28.
3. The lubricating oil composition according to claim 2, wherein
the friction modifier is a C.sub.10-C.sub.30 alkane 1,2-diol
derived from a linear alkyl containing from 14 to 18 carbon
atoms.
4. The lubricating oil composition according to claim 3, wherein
the friction modifier is in amount from 0.02 to 5.0 wt. % based
upon the total weight of the lubricating oil composition.
5. The lubricating oil composition according to claim 1, wherein
the overbased alkyl alkaline earth metal hydroxybenzoate detergent
having a metal ratio less than 3.0 has an alkyl chain length of 14
to 18 carbon atoms.
6. The lubricating oil composition according to claim 1, wherein
the overbased alkyl calcium sulfonate or an overbased alkyl calcium
hydroxybenzoate having a metal ratio of 3.5 or greater has an alkyl
chain length of 20 to 28 carbon atoms.
7. The lubricating oil composition according to claim 1, wherein
the overbased alkyl calcium sulfonate is selected having a metal
ratio of 3.5 or greater has an alkyl chain length of 20 to 28
carbon atoms.
8. The lubricating oil composition according to claim 1, wherein
the overbased alkyl calcium hydroxybenzoate is selected having a
metal ratio of 3.5 or greater has an alkyl chain length of 20 to 28
carbon atoms.
9. The lubricating oil composition according to claim 1, wherein
the base oil of lubricating viscosity has a viscosity index of
greater than 110.
10. The lubricating oil composition according to claim 9, wherein
the base oil of lubricating oil has a HTHS viscosity of less than
2.9 mPs at 150.degree. C. as determined by ASTM D4683.
11. The lubricating oil composition according to claim 10, wherein
the lubricating oil composition is formulated to meet SAE viscosity
grade 0W20.
12. The lubricating oil composition according to claim 9, wherein
the lubricating oil composition has a HTHS viscosity of less than
2.6 mPs at 150.degree. C. as determined by ASTM D4683.
13. The lubricating oil composition according to claim 9, wherein
the lubricating oil composition has a HTHS viscosity of less than
2.3 mPs at 150.degree. C. as determined by ASTM D4683.
14. The lubricating oil composition according to claim 13, wherein
the lubricating oil composition contains less than 3 wt % of
viscosity index improver component.
15. A lubricating oil composition for internal combustion engines
comprising: a. a major amount of base oil of lubricating viscosity;
b. a C.sub.10-C.sub.30 hydrocarbyl 1,2-diol in an amount from about
0.1 to 3 mass %; c. an overbased alkyl (C.sub.14-C.sub.18) alkaline
earth metal hydroxybenzoate detergent having a metal ratio less
than 3.0 in an amount from about 0.01 to 0.4 mass % based on
alkaline earth metal content; d. an overbased alkyl
(C.sub.20-C.sub.28) calcium sulfonate or an overbased alkyl
(C.sub.20-C.sub.28) calcium hydroxybenzoate having a metal ratio of
3.5 or greater in an amount from 0.01 to 0.4 mass % based on
calcium content; e. a nitrogen containing dispersant in terms of
nitrogen content from about 0.01 to 0.3 mass %; f. a zinc
dialkydithiophosphate in the amount from 0.01 to 0.1% in terms of
phosphorous content; g. an oxidation inhibitor selected from the
group consisting of a phenolic antioxidant or a diphenyl amine type
antioxidant in the amount from 0.1 to 7 mass %; and wherein the
mass % is based upon the total amount of the lubricating oil
composition.
Description
FIELD OF THE INVENTION
[0001] Disclosed is lubricating oil composition having a particular
vicinal diol friction modifier and detergent mixture having at
least two types of metallic detergents. The lubricating oil
composition demonstrates improved friction characteristics and is
particularly suited for low-viscosity lubricating oil
compositions.
BACKGROUND
[0002] Due to the combination of global regulations promoting fuel
efficiency and market demand, fuel economy has driven engine
builders to adopt changes to design (engines with smaller
tolerances, smaller displacement, direct fuel injection,
turbochargers, boosted intakes, start/stops, etc.). Additionally,
hardware technology including fuel-electric hybrid and idling stop
with engine design modification has placed important new
performance requirements on motor oils for passenger cars. Not only
must the motor oil address these added design effects, the engine
oils are also viewed as an area where additional performance may be
achieved. Notably, fuel economy performance of a lubricant is
affected by both the viscosity of the oil and additive
interactions.
[0003] Of the two factors, viscosity has long been regarded as
resulting in greater friction reduction and fuel economy. Moving to
a lower viscosity engine oil has been a recognized strategy to
improve vehicle fuel economy. Recently it has been discovered that
this trend does not hold as oils are developed with viscosities
that are far lower than those considered previously and thus cannot
be read across. For example, moving from an SAE viscosity grade
10W-30 oil to a 5W-30 viscosity oil results in the expected
improvement in fuel economy when utilizing the same chemistry in
the formulation, but moving to 0W-20 or lower has not demonstrated
this trend. One explanation is that this is the result of increased
friction in what are known as boundary lubrication situations.
These boundary lubrication situations are found when an engine is
running at low speed and high temperature. The lower viscosity oils
may be less able to maintain separation between moving parts in the
engine resulting in increased friction and lowering fuel economy.
In addition, as lubricants become thinner, concerns about engine
wear increase.
[0004] The use of appropriate additive systems is becoming
increasingly important. Additives in lubricants often include polar
functional groups which will draw the additive to the metal
surfaces in an engine. As a result of this interaction, many
additives are known to modify the friction performance of a
lubricant. Some additives, like detergents, are known to have a
negative effect on fuel economy by increasing friction. Balancing
the interactions of the additives in the lubricant; and the
benefits/potential drawbacks of lowered viscosity is a challenge
for today's formulators.
[0005] Herein, it is has been shown that certain combinations of
detergents and vicinal diol friction modifiers have been discovered
which show increased fuel economy benefits in conventional oil and
more particularly low viscosity oils of lubricating viscosity.
These benefits have been demonstrated through both bench and engine
testing.
[0006] Vicinal diols are known in the art to be employed in
lubricating oils. U.S. Pat. No. 4,406,803 teaches the use of
C.sub.10-C.sub.30 alkane 1,2-diols as friction modifiers in
lubricants for internal combustion engines. U.S. Pat. No. 4,331,222
teaches the use of C.sub.8-C.sub.28 alkane 1,2-diols in functional
fluids, particularly those for tractors, to reduce brake noise. JP
2000-017283 teaches the use of greater than C.sub.5 alkane
1,2-diols as lubricity agents. JP 2000-273481 teaches the
combination of C.sub.14-C.sub.22 alkane 1,2-diols with a detergent
having total base number greater than 60 in a base oil with
viscosity index of 80-150 for lubrication. WO 2010/115864 teaches
the use of C.sub.10-C.sub.24 diols in functional fluids
particularly for wet brakes. WO 20111007643 teaches the combination
of alkane or alkene 1,2-diols and zinc dithiophosphates in
lubricants for improved fuel economy. The class of friction
modifiers that includes alkane/alkene 1,2-diols has been in use for
decades. However, none of the lubricants previously described
address the problem of friction modification in very low viscosity
engine oils.
SUMMARY
[0007] An aspect of the present invention is directed to a
lubricating oil additive containing a vicinal diol and a particular
detergent blend typically is low viscosity base oils whereby
exhibiting improved fuel economy. In this respect, disclosed is a
lubricating oil composition comprising: a major amount of base oil
of lubricating viscosity; a friction modifier which is selected
from the group consisting of C.sub.10-C.sub.30 alkane 1,2-diols and
C.sub.10-C.sub.30 alkene 1,2-diols; an overbased alkyl alkaline
earth metal hydroxybenzoate detergent having a metal ratio less
than 3.0; and an overbased alkyl calcium sulfonate or an overbased
alkyl calcium hydroxybenzoate having a metal ratio of 3.5 or
greater. In a further aspect, the alkaline earth metal is
calcium.
[0008] An aspect is directed to lubricating oil compositions
wherein the vicinal diol friction modifier is selected from the
formula R.sub.1--CH(OH)CH.sub.2(OH) wherein R.sub.1 is alkyl
containing from 10 to 28 carbon atoms. More particularly disclosed
are wherein the friction modifier is a C.sub.10-C.sub.30 alkane
1,2-diol derived from a linear alkyl containing from 14 to 18
carbon atoms. In this regard the friction modifier is typically
employed in an amount from about 0.02 to about 5.0 wt. % based upon
the total weight of the lubricating oil composition.
[0009] An aspect is directed to a lubricating oil composition
comprising: a major amount of base oil of lubricating viscosity; a
friction modifier which is selected from the group consisting of
C.sub.10-C.sub.30 alkane 1,2-diols and C.sub.10-C.sub.30 alkene
1,2-diols; an overbased alkyl alkaline earth metal hydroxybenzoate
detergent having a metal ratio less than 3.0 has an alkyl chain
length of 14 to 18 carbon atoms; and an overbased alkyl calcium
sulfonate or an overbased alkyl calcium hydroxybenzoate having a
metal ratio of 3.5 or greater. In a further aspect, the alkyl chain
is linear alkyl. In a further aspect the alkaline earth metal is
selected from calcium.
[0010] An aspect is directed to a lubricating oil composition
comprising: a major amount of base oil of lubricating viscosity; a
friction modifier which is selected from the group consisting of
C.sub.10-C.sub.30 alkane 1,2-diols and C.sub.10-C.sub.30 alkene
1,2-diols; an overbased alkyl alkaline earth metal hydroxybenzoate
detergent having a metal ratio less than 3.0; and an overbased
alkyl calcium sulfonate or an overbased alkyl calcium
hydroxybenzoate having a metal ratio of 3.5 or greater has an alkyl
chain length of 20 to 28 carbon atoms. In a further aspect the
detergent having a metal ratio of 3.5 or greater is an overbased
alkyl calcium hydroxybenzoate; in another aspect the detergent
having a metal ratio of 3.5 or greater is an overbased alkyl
calcium sulfonate.
[0011] An aspect of the present invention is directed to the
features of the base oil, thus in one regard the base oil of
lubricating viscosity has a viscosity index of greater than 110.
More particularly, the base oil of lubricating oil is selected to
have a HTHS viscosity of less than 2.9 mPs at 150.degree. C. as
determined by ASTM D4683. Such other features of the base oil and
additives may be so selected such that the lubricating oil
composition is formulated to meet SAE viscosity grade 0W20. Lower
viscometrics in the selection of suitable base oils has provided
improvement frictional characteristics of the lubricating
composition of the present invention, thus one aspect is directed
to wherein the lubricating oil composition may have a base oil of
lubricating oil having a HTHS viscosity of less than 2.6 mPs at
150.degree. C. as determined by ASTM D4683 and even wherein the
base oil of lubricating oil has a HTHS viscosity of less than 2.3
mPs at 150.degree. C. as determined by ASTM D4683. In this regard,
the lubricating oil composition may be formulated to contain less
than 3 wt % of viscosity index improver component. In a further
aspect, the lubricating composition contains substantially no
viscosity index improver component.
[0012] An aspect of the present invention is directed to a fuel
economical lubricating oil composition particularly suited for
lubricating internal combustion engines such as diesel engines,
gasoline engines, and gas engines mounted on land traveling
vehicles. In this regard, disclosed is a lubricating oil
composition for internal combustion engines comprising: a major
amount of base oil of lubricating viscosity; a C.sub.10-C.sub.30
hydrocarbyl 1,2-diol in an amount from about 0.1 to 3 mass %; an
overbased alkyl (C.sub.14-C.sub.18) alkaline earth metal
hydroxybenzoate detergent having a metal ratio less than 3.0 in an
amount from about 0.01 to 0.4 mass % based on alkaline earth metal;
an overbased alkyl (C.sub.20-C.sub.28) calcium sulfonate or an
overbased alkyl (C.sub.20-C.sub.28) calcium hydroxybenzoate having
a metal ratio of 3.5 or greater in an amount from 0.01 to 0.4 mass
% based on calcium; a nitrogen containing dispersant in terms of
nitrogen content from about 0.01 to 0.3 mass %; a zinc
dialkydithiophosphate in the amount from 0.01 to 0.1% in terms of
phosphorous content; an oxidation inhibitor selected from the group
consisting of a phenolic antioxidant or a diphenyl amine type
antioxidant (or mixtures thereof) in the amount from 0.1 to 7 mass
%; and wherein the mass % is based upon the total amount of the
lubricating oil composition.
DETAILED DESCRIPTION
[0013] The term "alkali metal" or "alkaline metal" refers to
lithium, sodium or potassium.
[0014] The term "alkaline earth metal" refers to calcium, barium,
magnesium and strontium.
[0015] The term "alkaline earth alkylaryl sulfonate" refers to an
alkaline earth metal salt of an alkylaryl sulfonic acid. In other
words, it is an alkaline earth metal salt of an aryl that is
substituted with (1) an alkyl group and (2) a sulfonic acid group
that is capable of forming a metal salt.
[0016] The term "alkyl" refers to both straight- and branched-chain
alkyl groups.
[0017] The term "alkylphenate" means a metal salt of an
alkylphenol.
[0018] The term "alkylphenol" means a phenol having one or more
alkyl substituents, wherein at least one of the alkyl substituents
has a sufficient number of carbon atoms to impart oil solubility to
the phenol.
[0019] The term "aryl group" is a substituted or non-substituted
aromatic group, such as the phenyl, tolyl, xylyl, ethylphenyl and
cumenyl groups.
[0020] The term "calcium base" refers to a calcium hydroxide,
calcium oxide, calcium alkoxides, and the like, and mixtures
thereof.
[0021] The term "hydrocarbyl" means a group or radical that
contains carbon and hydrogen atoms and that is bonded to the
remainder of the molecule via a carbon atom. It may contain hetero
atoms, i.e. atoms other than carbon and hydrogen, provided they do
not alter the essentially hydrocarbon nature and characteristics of
the group. As examples of hydrocarbyl, there may be mentioned alkyl
and alkenyl.
[0022] The term "hydrocarbyl phenol" refers to a phenol having one
or more hydrocarbyl substituent; at least one of which has
sufficient number of carbon atoms to impart oil solubility to the
phenol.
[0023] The term "lime" refers to calcium hydroxide, also known as
slaked lime or hydrated lime.
[0024] The term "metal" means alkali metals, alkaline earth metals,
or mixtures thereof.
[0025] The term "metal base" refers to a metal hydroxide, metal
oxide, metal alkoxides and the like and mixtures thereof, wherein
the metal is selected from the group consisting of lithium, sodium,
potassium, magnesium, calcium, strontium, barium or mixtures
thereof.
[0026] The term "overbased" refers to a class of metal salts or
complexes. These materials have also been referred to as "basic",
"superbased", "hyperbased", "complexes", "metal complexes",
"high-metal containing salts", and the like. Overbased products are
metal salts or complexes characterized by a metal content in excess
of that which would be present according to the stoichiometry of
the metal and the particular acidic organic compound reacted with
the metal, e.g., a carboxylic acid.
[0027] The term "phenate" means a metal salt of a phenol.
[0028] The term "Total Base Number" or "TBN" refers to the
equivalent number of milligrams of KOH needed to neutralize 1 gram
of a product. Therefore, a high TBN reflects strongly overbased
products and, as a result, a higher base reserve for neutralizing
acids. The TBN of a product can be determined by ASTM Standard No.
D2896 or equivalent procedure.
[0029] The term "SAE J300" refers to SAEJ300: "Engine Oil Viscosity
Classification" January 2009 version.
[0030] Hydrocarbyl Diol:
[0031] The hydrocarbyl diols contemplated for use in this invention
are hydrocarbyl diols having vicinal hydroxyls. They have the
formula: R--(OH).sub.2 wherein R is a hydrocarbyl group containing
10 to 30 carbon atoms, including mixtures thereof. R can be linear
or branched, saturated or unsaturated. Particularly, R is straight
chain alkyl or alkene group wherein the alkene group has two or
less unsaturated bonds, a single unsaturated bond. The two hydroxyl
groups are preferably near the end of the hydrocarbyl chain and are
on adjacent carbon atoms (vicinal).
[0032] As disclosed hereinabove, the preferred vicinal diols
contain 10 to 30 carbon atoms. This range is preferred because
diols having much less than 10 or 12 carbon atoms have
significantly less friction reducing properties, while in those
having more than 30 carbon atoms, solubility constraints become
significant. More preferred are the C.sub.14 to C.sub.18
hydrocarbyl groups and mixtures of such hydrocarbyl groups in which
solubility, frictional characteristics and other properties appear
to be maximized.
[0033] A more preferred vicinal diols are represented by
alkane-1,2-diols of the formula R.sub.1--CH(OH)CH.sub.2(OH) wherein
R.sub.1 is alkyl containing from 8 to 28 carbon atoms, or mixtures
thereof. Straight and branched chain alkyl groups may be employed.
Particularly useful are linear olefins or blends of linear olefins,
are terminal olefins, as contrasted to internal olefins. The
preferred linear olefins are alpha olefins fractions having a major
amount of n-alpha olefins. As used herein, major amount refers to
greater than about 50 wt % n-alpha olefin, and preferably greater
than about 80 wt %. Examples of the alpha-olefins include 1-decene,
1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,
1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene,
1-eicosene, 1-heneicosene, 1-docosene, 1-tetracosene, etc.
Commercially available alpha-olefin fractions that can be used
include the C15-18 alpha-olefins, C12-16 alpha-olefins, C14-16
alpha-olefins, C14-18 alpha-olefins, C16-18 alpha-olefins, C16-20
alpha-olefins, C18-24 alpha-olefins, C20-24 alpha-olefins, C22-28
alpha-olefins, C24-28 alpha-olefins, C26-28 alpha-olefins, etc.
Suitable n-alpha olefins can be derived from the ethylene chain
growth process. This process yields even numbered straight chain
1-olefins from a controlled Ziegler polymerization. Non-Ziegler
ethylene chain growth oligomerization routes are also known in the
art. Other methods for preparing the alpha olefins of this
invention include wax cracking as well as catalytic dehydrogenation
of normal paraffins. However, these latter processes typically
require further processing techniques to provide a suitable alpha
olefin carbon distribution.
[0034] Single carbon number species may be employed such as
decane-1,2-diol, octadecane-1,2-diol, eicosane-1,2-diol,
tricontane-1,2-diol, and the like, but a blend of several carbon
numbers is preferred. Typical blends include the 1,2-diols of 10 to
30 (incl.) carbon atom alkanes; the 1,2-diols of 12, 14, 16, 18 and
20 carbon atom alkanes; the 1,2-diols of 15 to 20 (incl.) carbon
atom alkanes; the 1,2-diols of 15 to 18 (incl.) carbon atom
alkanes; the 1,2-diols of 20 to 24 (incl.) carbon atom alkanes; the
1,2-diols of 24, 26 and 28 carbon atom alkanes; the 1,2-diols of 16
to 18 (incl.) carbon atom alkanes; and the like.
[0035] The diols useful for this invention are either commercially
available or are readily prepared from the corresponding 1-olefin
by methods well known in the art. For example, the olefin is first
reacted with peracid, such as peroxyacetic acid or hydrogen
peroxide plus formic acid to form an alkane-1,2-epoxide which is
readily hydrolyzed under acid or base catalysis to the
alkane-1,2-diol. In another process, the olefin is first
halogenated to a 1,2-dihalo-alkane and subsequently hydrolyzed to
an alkane-1,2-diol by reaction first with sodium acetate and then
with sodium hydroxide. Vicinal diols can also be prepared by the
peroxytrifluoroacetic acid method for the hydroxylation of other
procedures are well know and can be found in U.S. Pat. Nos.
2,411,762; 2,457,329 and 2,455,892. The diols can also be prepared
via catalytic epoxidation of an appropriate olefin, followed by
hydrolysis.
[0036] Particularly preferred diols contemplated are
1,2-decanediol, 1,2-dodecanediol, 1,2-tetradecanediol,
1,2-pentadecanediol, 1,2-hexadecanediol, 1,2-heptadecanediol,
1,2-octadecanediol, etc. mixed 1,2-C.sub.15-C.sub.18 alkanediols,
mixed 1,2-C.sub.13-C.sub.16 alkanediols, mixed
1,2-C.sub.16-C.sub.18 alkanediols, and mixtures of all such diols,
including mixtures of similar diols. Other suitable diol are
derived from the C12-16 alpha-olefins, C14-16 alpha-olefins, C14-18
alpha-olefins, and C16-20 alpha-olefins commercial fractions.
[0037] Detergent Mixture:
[0038] The detergent mixture comprising at least a first overbased
metal hydrocarbyl-substituted hydroxybenzoate having a metal ratio
of less than or equal to 3. Also included in the detergent mixture
is a second metal detergent which is different from the first
detergent, having a metal ratio of greater than or equal to 3.5.
The second detergent is either an overbased metal
hydrocarbyl-substituted hydroxybenzoate or an overbased metal alkyl
aryl sulfonate.
[0039] The overbased metal hydrocarbyl-substituted hydroxybenzoate
typically has the structure shown:
##STR00001##
wherein R.sub.a is a linear aliphatic group, branched aliphatic
group or a mixture of linear and branched aliphatic groups. There
may be more than on R.sub.a group attached to the benzene ring,
however dialkyl attachment is less than 5% and is not expected to
alter performance. Preferably, R.sub.a is an alkyl or alkenyl
group. More preferably, R.sub.a is an straight or branched chain
alkyl group from 9 to 40 carbon atoms. When R.sub.a is a linear
aliphatic group, the linear alkyl group typically comprises from
about 12 to 40 carbon atoms, more preferably from about 14 to 30
carbon atoms. When R.sub.a is a branched aliphatic group, the
branched alkyl group typically comprises at least 9 carbon atoms
preferably from about 9 to 24 carbon atoms and most preferably from
about 10 to 18 carbon atoms. Such branched aliphatic groups are
preferably derived from an oligomer of propylene or butene.
[0040] R.sub.a can also represent a mixture of linear or branched
aliphatic groups. When R.sub.a represents a mixture of aliphatic
groups, the alkaline-earth metal alkylhydroxybenzoic acid employed
in the present invention may contain a mixture of linear groups, a
mixture of branched groups, or a mixture of linear and branched
groups. Thus, R.sub.a can be a mixture of linear aliphatic groups,
preferably alkyl; for example, an alkyl group selected from the
group consisting of C.sub.14-C.sub.16, C.sub.14-C.sub.18,
C.sub.16-C.sub.18, C.sub.18-C.sub.20, C.sub.20-C.sub.22,
C.sub.20-C.sub.24 and C.sub.20-C.sub.28 alkyl and mixtures thereof
and derived from normal alpha olefins. Advantageously, these
mixtures include at least 95 mole %, preferably 98 mole % of alkyl
groups originating from the polymerization of ethylene.
[0041] M is an alkaline earth metal selected of the group
consisting of calcium, barium, magnesium, strontium. Calcium and
magnesium are the preferred alkaline earth metal. Calcium is more
preferred. Wherein y and z are independently whole or partial
integers.
[0042] The --COOM group of Formula can be in the ortho, meta or
para position with respect to the hydroxyl group, wherein the ortho
position is preferred in one aspect. The R.sub.a group can be in
the ortho, meta or para position with respect to the hydroxyl
group.
[0043] The alkaline earth metal alkylhydroxybenzoates of the
present invention can be any mixture of alkaline-earth metal
alkylhydroxybenzoic acid having the --COOM group in the ortho, meta
or para position.
[0044] The alkaline earth metal alkylhydroxybenzoates of the
present invention are generally soluble in oil as characterized by
the following test: A mixture of a 600 Neutral diluent oil and the
alkylhydroxybenzoate at a content of 10 wt % with respect to the
total weight of the mixture is centrifuged at a temperature of
60.degree. C. and for 30 minutes, the centrifugation being carried
out under the conditions stipulated by the standard ASTM D2273 (it
should be noted that centrifugation is carried out without
dilution, i.e. without adding solvent); immediately after
centrifugation, the volume of the deposit which forms is
determined; if the deposit is less than 0.05% v/v (volume of the
deposit with respect to the volume of the mixture), the product is
considered as soluble in oil.
[0045] Hydroxybenzoic acids are typically prepared by the
carboxylation, by the Kolbe-Schmitt process, from phenoxides, and
in that case, will generally be obtained (normally in a diluent) in
admixture with uncarboxylated phenol. Hydroxybenzoic acids may be
non-sulphurized or sulphurized, and may be chemically modified
and/or contain additional substituents. Processes for sulphurizing
a hydrocarbyl-substituted hydroxybenzoic acid are well known to
those skilled in the art, and are described, for example, in US
Patent Application No. 2007/0027057.
[0046] The term "overbased" is generally used to describe metal
detergents in which the metal ratio, the ratio of the number of
equivalents of the metal moiety to the number of equivalents of the
acid moiety, is greater than one. The term low-based' is used to
describe metal detergents in which the metal ratio is greater than
1, and up to about 2.5.
[0047] By an "overbased calcium salt of surfactants" is meant an
overbased detergent in which the metal cations of the oil-insoluble
metal salt are essentially calcium cations. Small amounts of other
cations may be present in the oil-insoluble metal salt, but
typically at least 80, more typically at least 90, for example at
least 95, mole % of the cations, in the oil-insoluble metal salt,
are calcium ions. Cations other than calcium may be derived, for
example, from the use in the manufacture of the overbased detergent
of a surfactant salt in which the cation is a metal other than
calcium. Preferably, the metal salt of the surfactant is also
calcium.
[0048] Carbonated overbased metal detergents typically comprise
amorphous nanoparticles. Additionally, there are disclosures of
nanoparticulate materials comprising carbonate in the crystalline
calcite and vaterite forms.
[0049] The basicity of the detergents may also be expressed as a
total base number (TBN). A total base number is a measure of the
alkalinity of the overbased material. It is expressed as mg of
KOH/g of material. The TBN may be measured using ASTM standard
D2896 or an equivalent procedure. The detergent may have a neutral
TBN (i.e. a TBN of less than 100), a medium TBN (i.e. a TBN of 100
to 250) or a high TBN (i.e. a TBN of greater than 250, such as
250-500).
[0050] Overbased metal hydrocarbyl-substituted hydroxybenzoates can
be prepared by any of the techniques employed in the art. A general
method is as follows: 1. Neutralization of hydrocarbyl-substituted
hydroxybenzoic acid with a molar excess of metallic base to produce
a slightly overbased metal hydrocarbyl-substituted hydroxybenzoate
complex, in a solvent mixture consisting of a volatile hydrocarbon,
an alcohol and water; 2. Carbonation to produce
colloidally-dispersed metal carbonate followed by a post-reaction
period; 3. Removal of residual solids that are not colloidally
dispersed; and 4. Stripping to remove process solvents.
[0051] Overbased metal hydrocarbyl-substituted hydroxybenzoates can
be made by either a batch or a continuous overbasing process.
[0052] Metal base (e.g. metal hydroxide, metal oxide or metal
alkoxide), preferably lime (calcium hydroxide), may be charged in
one or more stages. The charges may be equal or may differ, as may
the carbon dioxide charges which follow them. When adding a further
calcium hydroxide charge, the carbon dioxide treatment of the
previous stage need not be complete. As carbonation proceeds,
dissolved hydroxide is converted into colloidal carbonate particles
dispersed in the mixture of volatile hydrocarbon solvent and
non-volatile hydrocarbon oil.
[0053] Carbonation may be effected in one or more stages over a
range of temperatures up to the reflux temperature of the alcohol
promoters. Addition temperatures may be similar, or different, or
may vary during each addition stage. Phases in which temperatures
are raised, and optionally then reduced, may precede further
carbonation steps.
[0054] The volatile hydrocarbon solvent of the reaction mixture is
preferably a normally liquid aromatic hydrocarbon having a boiling
point not greater than about 150.degree. C. Aromatic hydrocarbons
have been found to offer certain benefits, e.g. improved filtration
rates, and examples of suitable solvents are toluene, xylene, and
ethyl benzene.
[0055] The alkanol is preferably methanol although other alcohols
such as ethanol can be used. Correct choice of the ratio of alkanol
to hydrocarbon solvents, and the water content of the initial
reaction mixture, are important to obtain the desired product.
[0056] Oil may be added to the reaction mixture; if so, suitable
oils include hydrocarbon oils, particularly those of mineral
origin. Oils which have viscosities of 15 to 30 mm2/sec at
38.degree. C. are very suitable.
[0057] After the final treatment with carbon dioxide, the reaction
mixture is typically heated to an elevated temperature, e.g. above
130.degree. C., to remove volatile materials (water and any
remaining alkanol and hydrocarbon solvent). When the synthesis is
complete, the raw product is hazy as a result of the presence of
suspended sediments. It is clarified by, for example, filtration or
centrifugation. These measures may be used before, or at an
intermediate point, or after solvent removal.
[0058] The products are generally used as an oil solution. If the
reaction mixture contains insufficient oil to retain an oil
solution after removal of the volatiles, further oil should be
added. This may occur before, or at an intermediate point, or after
solvent removal.
[0059] Advantageously, the TBN of the middle overbased alkaline
earth metal alkylhydroxybenzoate of the present invention, the TBN
is from about 100 to 250, preferably from about 140 to 230 and will
generally have less than 1 volume %, preferably less than 0.5
volume % crude sediment. In this regard, the middle overbased
alkaline earth metal alkylhydroxybenzoate of the present invention
may be a single detergent or a mixture. In one aspect, a lower TBN
from about (140-175) having a metal ratio of less than 3.0,
preferably less than 2.5 is employed; in this regard, preferred
alkyl chains are derived from linear alpha olefins having from 14
to 18 carbon atoms. In another aspect, a second middle overbased
alkaline earth metal alkylhydroxybenzoate may be employed (with or
in lieu of the lower TBN material) having a TBN from about
(200-240) having a metal ratio of greater than 4.0 is employed; in
this regard, preferred alkyl chains are derived from linear alpha
olefins having from 20 to 28 carbon atoms. For the high overbased
alkaline earth metal alkylhydroxybenzoate of the present invention
is greater than 250, preferably from about 250 to 450 and more
preferably from about 300 to 400 and will generally have less than
3 volume %, preferably less than 2 volume % and more preferably
less than 1 volume % crude sediment. This higher TBN material will
have a metal ratio greater than 6, preferable about 8; in this
regard, preferred alkyl chains are derived from linear alpha
olefins having from 20 to 28 carbon atoms.
[0060] In addition to the one or more overbased metal
hydrocarbyl-substituted hydroxybenzoates described herein above, an
addition suitable detergent may be selected from the slate of
typical lubricating oil detergents; and as used herein it is
distinct and different from the first detergent. Common examples of
metal detergents included: sulfonates, alkylphenates, sulfurized
alkyl phenates, carboxylates, salicylates, phosponates, and
phosphinates. Overbased metal sulfonates are generally produced by
carbonating a mixture of hydrocarbons, sulfonic acid, metal oxide
or hydroxides (for example calcium oxide or calcium hydroxide) and
promoters such as xylene, methanol and water. For example for
preparing an overbased calcium sulfonate; in carbonation, the
calcium oxide or hydroxide reacts with the gaseous carbon dioxide
to form calcium carbonate. The sulfonic acid is neutralized with an
excess of CaO or Ca(OH), to form the sulfonate. The prior art known
processes for overbasing calcium sulfonates generally produces high
alkaline reserves of TBN of 300 to 400 mg KOH/gm or higher.
Commercially available high TBN, up to approximately 400 TBN
sulfonates, have enabled the formulator to use lower amounts of
acid neutralizing additive while maintaining equivalent detergency,
thus protecting the engine adequately under conditions of high acid
formation in the combustion process. One aspect discloses that
employing high TBN sulfonates (greater that 400 TBN, metal ratio 16
or greater) with the lower metal ratio overbased alkaline earth
metal alkylhydroxybenzoate, in an automobile crankcase engine oil
formulation can lead to improvements in fuel economy.
[0061] Also included within the meaning of "sulfonate" are the
salts of sulfonic acids of synthetic alkyl aryl compounds, which
often are preferred. These acids also are prepared by treating an
alkyl aryl compound with sulfuric acid or sulfur trioxide. At least
one alkyl substituent of the aryl ring is an oil-solubilizing
group, as discussed above. The acids thus obtained are known as
synthetic alkyl aryl sulfonic acids and the salts as alkyl aryl
sulfonates. The sulfonates where the alkyl is straight-chain are
the well-known linear alkylaryl sulfonates. Typically these
obtained by the olio-polymerization of ethylene to C.sub.14 to
C.sub.40 hydrocarbons followed by alkylation via a Friedel and
Craft reaction of an aryl hydrocarbon. Branched olefins can be
obtained from the oligo-polymerization of for example, propylene to
C.sub.15 to C.sub.42 hydrocarbons and particularly the propylene
tetrapolymer dimerized to a C.sub.24 olefin, or alkylation of
aromatics using normal alpha olefins. Preferred aryl groups are
phenyl and substituted phenyl, preferably tolyl, xylyl,
particularly ortho xylyl, ethyl phenyl, cumenyl and the like.
[0062] The acids obtained by sulfonation are converted to the metal
salts by neutralizing with a basic reacting alkali or alkaline
earth metal compound to yield the Group I or Group II metal
sulfonates. Generally, the acids are neutralized with an alkali
metal base. Alkaline earth metal salts are obtained from the alkali
metal salt by metathesis. Alternatively, the sulfonic acids can be
neutralized directly with an alkaline earth metal base. The
sulfonates are then overbased and such overbased materials and
methods of preparing such materials are known to those skilled in
the art. See, for example, LeSuer U.S. Pat. No. 3,496,105, issued
Feb. 17, 1970, particularly Cols. 3 and 4.
[0063] The sulfonates are present in the lubricating oil
composition in the form of alkaline earth metal salts, or mixtures
thereof. The alkaline earth metals include magnesium, calcium and
barium, of which calcium is preferred. The sulfonates are
superalkalinized employing excess alkaline metal base carbon
dioxide or other suitable base source. Often this is added
sequentially or step wise addition with or without a promoter,
paying particular attention to the overbasing process since
improper overbasing will lead to highly viscous sulfonates or lower
overbased than desired.
[0064] Particularly preferred, however, because of their wide
availability, are salts of the petroleum sulfonic acids,
particularly the petroleum sulfonic acids which are obtained by
sulfonating various hydrocarbon fractions such as lubricating oil
fractions and extracts rich in aromatics which are obtained by
extracting a hydrocarbon oil with a selective solvent, which
extracts may, if desired, be alkylated before sulfonation by
reacting them with olefins or alkyl chlorides by means of an
alkylation catalyst; organic polysulfonic acids such as benzene
disulfonic acid which may or may not be alkylated; and the
like.
[0065] The preferred salts for use in the present invention are
those of alkylated aromatic sulfonic acids in which the alkyl
radical or radicals contain at least about 8 carbon atoms, for
example from about 8 to 40 carbon atoms. Another preferred group of
sulfonate starting materials are the aliphatic-substituted cyclic
sulfonic acids in which the aliphatic substituents or substituents
contain a total of at least 12 carbon atoms, such as the alkyl aryl
sulfonic acids, alkyl cycloaliphatic sulfonic acids, the alkyl
heterocyclic sulfonic acids and aliphatic sulfonic acids in which
the aliphatic radical or radicals contain a total of at least 12
carbon atoms. Specific examples of these oil-soluble sulfonic acids
include petroleum sulfonic acid, petrolatum sulfonic acids, mono-
and poly-wax-substituted naphthalene sulfonic acids, substituted
sulfonic acids, such as cetyl benzene sulfonic acids, cetyl phenyl
sulfonic acids, and the like, aliphatic sulfonic acid, such as
paraffin wax sulfonic acids, hydroxy-substituted paraffin wax
sulfonic acids, etc., cycloaliphatic sulfonic acids, petroleum
naphthalene sulfonic acids, cetyl cyclopentyl sulfonic acid, mono-
and poly-wax-substituted cyclohexyl sulfonic acids, and the like.
The term "petroleum sulfonic acids" is intended to cover all
natural sulfonic acids that are derived directly from petroleum
products. Typical Group II metal sulfonates suitable for use in
this composition include the metal sulfonates exemplified as
follows: calcium white oil benzene sulfonate, barium white oil
benzene sulfonate, magnesium white oil benzene sulfonate, calcium
dipolypropene benzene sulfonate, barium dipolypropene benzene
sulfonate, magnesium dipolypropene benzene sulfonate, calcium
mahogany petroleum sulfonate, barium mahogany petroleum sulfonate,
magnesium mahogany petroleum sulfonate, calcium triacontyl
sulfonate, magnesium triacontyl sulfonate, calcium lauryl
sulfonate, barium lauryl sulfonate, magnesium lauryl sulfonate,
etc.
[0066] Also preferred are synthetic alkylaryl sulfonates.
Particularly useful are synthetic alkylaryl sulfonates having the
aryl sulfonate attached at the 1 or 2 position of the alkyl group,
preferably greater than 5 mole %, more preferably greater than 13
mole % and more preferably greater than 20 mole %, as these have
shown good compatibility and solubility while not forming a skin at
these levels of overbasing. Preferred are linear monoalkyl
sulfonates. Preferably the alkyl chain contains between 14 and 40
carbons and more preferably the alkylaryl sulfonate is derived from
a C.sub.14-C.sub.40 normal alpha olefin and more particularly from
a C.sub.20-C.sub.28 or a C.sub.20-C.sub.24 normal alpha olefin. In
this regard, the alkyaryl sulfonate derived from a
C.sub.20-C.sub.28 or a C.sub.20-C.sub.24 normal alpha olefin and is
overbased to have a high TBN (i.e. a TBN of greater than 250, such
as 250-500), preferably with a metal ratio greater or equal to 8,
preferably 10-20, more preferably 16-18.
[0067] Mixtures of high TBN sulfonates can be employed including
mixtures of natural sulfonates and synthetic sulfonates, mixtures
of synthetic sulfonates such as mixtures of monoalkyl and dialkyl
sulfonates, mixtures of monoalkyl and polyalkyl sulfonates or
mixtures of dialkyl and polyalkyl sulfonates.
[0068] Lubricating Oil Composition
[0069] The present invention also relates to lubricating oil
compositions containing the hydrocarbyl diol and the overbased
alkylated hydroxyaromatic carboxylate detergent mixtures of the
present invention. Such lubricating oil compositions will comprise
a major amount of a base oil of lubricating viscosity and a minor
amount of the hydrocarbyl diol and overbased alkylated
hydroxyaromatic carboxylate detergent mixtures of the present
invention.
[0070] Base oil as used herein is defined as a base stock or blend
of base stocks which is a lubricant component that is produced by a
single manufacturer to the same specifications (independent of feed
source or manufacturer's location); that meets the same
manufacturer's specification; and that is identified by a unique
formula, product identification number, or both. Base stocks may be
manufactured using a variety of different processes including but
not limited to distillation, solvent refining, hydrogen processing,
oligomerization, esterification, and rerefining. Rerefined stock
shall be substantially free from materials introduced through
manufacturing, contamination, or previous use. The base oil of this
invention may be any natural or synthetic lubricating base oil
fraction particularly those having a kinematic viscosity at
100.degree. C. and about 4 centistokes (cSt) to about 20 cSt.
Hydrocarbon synthetic oils may include, for example, oils prepared
from the polymerization of ethylene, polyalphaolefin or PAO, or
from hydrocarbon synthesis procedures using carbon monoxide and
hydrogen gases such as in a Fisher-Tropsch process. A preferred
base oil is one that comprises little, if any, heavy fraction;
e.g., little, if any, lube oil fraction of viscosity about 20 cSt
or higher at about 100.degree. C. Oils used as the base oil will be
selected or blended depending on the desired end use and the
additives in the finished oil to give the desired grade of engine
oil, e.g. a lubricating oil composition having an SAE Viscosity
Grade of 0W-20, 0W-30, 0W-40, 0W-50, 0W-60, 5W, 5W-20, 5W-30,
5W-40, 5W-50, 5W-60, 10W, 10W-20, 10W-30, 10W-40, 10W-50, 15W,
15W-20, 15W-30, or 15W-40.
[0071] In one aspect, the present invention is directed to the use
of lower viscosity grades. Recent improvements in the engine
hardware and manufacturing have allowed for the opportunity to use
lower viscosity grades in vehicles while maintaining durability and
provided new and increased demand for fuel economy. Herein these
are referred to as to ultra-low viscosity passenger car engine oil
compositions.
[0072] The base oil may be derived from natural lubricating oils,
synthetic lubricating oils or mixtures thereof. Suitable base oil
includes base stocks obtained by isomerization of synthetic wax and
slack wax, as well as hydrocrackate base stocks produced by
hydrocracking (rather than solvent extracting) the aromatic and
polar components of the crude. Suitable base oils include those in
all API categories I, II, III, IV and V as defined in API
Publication 1509, 14th Edition, Addendum I, December 1998. Group IV
base oils are polyalphaolefins (PAO). Group V base oils include all
other base oils not included in Group I, II, III, or IV. Group III
base oils are preferred, also are mixtures of Group II/III and
mixtures of Group III/IV.
[0073] Commonly mixtures of base oils may be employed. Group II
base stocks contain greater than or equal to 90 percent saturates;
less than or equal to 0.03 percent sulfur; and a viscosity index
greater than or equal to 80 and less than 210. Manufacturing plants
that make Group II base stocks typically employ hydroprocessing
such as hydrocracking or severe hydrotreating to increase the VI of
the crude oil to the specifications value. The use of
hydroprocessing typically increases the saturate content above 90%
and reduces the sulfur below 300 ppm. Group II base stocks useful
in the current inventions have a kinematic viscosity at 100.degree.
C. of about 2 to 14 cSt.
[0074] Group III base stocks contain greater than or equal to 90
percent saturates; less than or equal to 0.03 percent sulfur; and a
viscosity index greater than or equal to 120. Group III base stocks
are usually produced using a three-stage process involving
hydrocracking an oil feed stock, such as vacuum gas oil, to remove
impurities and to saturate all aromatics which might be present to
produce highly paraffinic lube oil stock of very high viscosity
index, subjecting the hydrocracked stock to selective catalytic
hydrodewaxing which converts normal paraffins into branched
paraffins by isomerization followed by hydrofinishing to remove any
residual aromatics, sulfur, nitrogen or oxygenates. Group III base
stocks useful in the current inventions have a kinematic viscosity
at 100.degree. C. of about 3 to 9 cSt.
[0075] Group IV low viscosity base oils may be incorporated into
the formulations.
[0076] One aspect is directed to low viscosity passenger car engine
oil compositions with a kinematic viscosity at 100.degree. C. of
from 3 to 9.3 cSt, more preferably wherein the composition has a
kinematic viscosity at 100.degree. C. of from 3 to 8.2 cSt, a Noack
volatility of less than 15% as determined by ASTM D5800, a CCS
viscosity of less than 5120 cP at -35.degree. C. as determined by
ASTM D5293, and an HTHS viscosity of less than 2.9 mPs at
150.degree. C. as determined by ASTM D4683, more preferably an HTHS
viscosity of less than or equal to 2.6 mPs at 150.degree. C. as
determined by ASTM D4683. One aspect is directed to low viscosity
passenger car engine wherein the oil compositions has a kinematic
viscosity at 100.degree. C. of from 4 to 6.9 cSt, a Noack
volatility of less than 15% as determined by ASTM D5800, a CCS
viscosity of less than 4820 cP at -35.degree. C. as determined by
ASTM D5293, and an HTHS viscosity of less than 2.6 mPs at
150.degree. C. as determined by ASTM D4683.
[0077] Natural lubricating oils may include animal oils, vegetable
oils (e.g., rapeseed oils, castor oils and lard oil), petroleum
oils, mineral oils, and oils derived from coal or shale. Synthetic
oils may include hydrocarbon oils and halo-substituted hydrocarbon
oils such as polymerized and inter-polymerized olefins,
alkylbenzenes, polyphenyls, alkylated diphenyl ethers, alkylated
diphenyl sulfides, as well as their derivatives, analogues and
homologues thereof, and the like. Synthetic lubricating oils also
include alkylene oxide polymers, interpolymers, copolymers and
derivatives thereof wherein the terminal hydroxyl groups have been
modified by esterification, etherification, etc. Another suitable
class of synthetic lubricating oils comprises the esters of
dicarboxylic acids with a variety of alcohols. Esters useful as
synthetic oils also include those made from C.sub.5 to C.sub.12
monocarboxylic acids and polyols and polyol ethers. Tri-alkyl
phosphate ester oils such as those exemplified by tri-n-butyl
phosphate and tri-iso-butyl phosphate are also suitable for use as
base oils.
[0078] Silicon-based oils (such as the polyalkyl-, polyaryl-,
polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils)
comprise another useful class of synthetic lubricating oils. Other
synthetic lubricating oils include liquid esters of
phosphorus-containing acids, polymeric tetrahydrofurans,
polyalphaolefins, and the like.
[0079] The base oil may be derived from unrefined, refined,
rerefined oils, or mixtures thereof. Unrefined oils are obtained
directly from a natural source or synthetic source (e.g., coal,
shale, or tar sand bitumen) without further purification or
treatment. Examples of unrefined oils include a shale oil obtained
directly from a retorting operation, a petroleum oil obtained
directly from distillation, or an ester oil obtained directly from
an esterification process, each of which may then be used without
further treatment. Refined oils are similar to the unrefined oils
except that refined oils have been treated in one or more
purification steps to improve one or more properties. Suitable
purification techniques include distillation, hydrocracking,
hydrotreating, dewaxing, solvent extraction, acid or base
extraction, filtration, and percolation, all of which are known to
those skilled in the art. Rerefined oils are obtained by treating
used oils in processes similar to those used to obtain the refined
oils. These rerefined oils are also known as reclaimed or
reprocessed oils and often are additionally processed by techniques
for removal of spent additives and oil breakdown products.
[0080] Base oil derived from the hydroisomerization of wax may also
be used, either alone or in combination with the aforesaid natural
and/or synthetic base oil. Such wax isomerate oil is produced by
the hydroisomerization of natural or synthetic waxes or mixtures
thereof over a hydroisomerization catalyst.
[0081] It is preferred to use a major amount of base oil in the
lubricating oil composition of the present invention. A major
amount of base oil as defined herein comprises 50 wt or more.
Preferred amounts of base oil comprise from about greater than 50
wt % to 97 wt %, more preferably from about 60 wt % to 97 wt % and
most preferably from about 80 wt % to 95 wt % of the lubricating
oil composition. (When weight percent is used herein, it is
referring to weight percent of the lubricating oil unless otherwise
specified.)
[0082] The overbased alkylated hydroxyaromatic carboxylate (i.e.,
overbased alkali metal alkylhydroxybenzoate) and second detergent
mixture system will be present in the lubricating oil composition
will be in a minor amount compared to the base oil of lubricating
viscosity. Generally, it will be in an amount from about 1 wt % to
25 wt %, preferably from about 2 wt % to 12 wt % and more
preferably from about 3 wt % to 8 wt %, based on the total weight
of the lubricating oil composition.
[0083] The hydrocarbyl diol is preferably an oil soluble organic
friction modifier and typically is incorporated in the lubricating
oil composition in an amount of from about 0.02 to 10.0 wt. % of
the lubricating oil composition. Preferably, from 0.05 to 2.0, more
preferably from 0.05 to 1.0 wt, more preferably from 0.1 to 0.5 wt.
% of the friction modifier is used.
[0084] Other Additive Components
[0085] The following additive components are examples of components
that can be favorably employed in combination with the lubricating
additive of the present invention. These examples of additives are
provided to illustrate the present invention, but they are not
intended to limit it.
[0086] The Dispersant
[0087] The dispersant employed in the compositions of this
invention can be ashless dispersants such as an alkenyl
succinimide, an alkenyl succinic anhydride, an alkenyl succinate
ester, and the like, or mixtures of such dispersants.
[0088] Ashless dispersants are broadly divided into several groups.
One such group is directed to copolymers which contain a
carboxylate ester with one or more additional polar function,
including amine, amide, imine, imide, hydroxy carboxyl, and the
like. These products can be prepared by copolymerization of long
chain alkyl acrylates or methacrylates with monomers of the above
function. Such groups include alkyl methacrylate-vinyl
pyrrolidinone copolymers, alkyl methacrylate-dialkylaminoethy
methacrylate copolymers and the like. Additionally, high molecular
weight amides and polyamides or esters and polyesters such as
tetraethylene pentamine, polyvinyl polysterarates and other
polystearamides may be employed. Preferred dispersants are
N-substituted long chain alkenyl succinimides.
[0089] Mono and bis alkenyl succinimides are usually derived from
the reaction of alkenyl succinic acid or anhydride and alkylene
polyamines. The actual reaction product of alkylene or alkenylene
succinic acid or anhydride and alkylene polyamine will comprise the
mixture of compounds including succinamic acids and succinimides.
However, it is customary to designate this reaction product as a
succinimide of the described formula, since this will be a
principal component of the mixture. The mono alkenyl succinimide
and bis alkenyl succinimide produced may depend on the charge mole
ratio of polyamine to succinic groups and the particular polyamine
used. Charge mole ratios of polyamine to succinic groups of about
1:1 may produce predominately mono alkenyl succinimide. Charge mole
ratios of polyamine to succinic group of about 1:2 may produce
predominately bis alkenyl succinimide.
[0090] These N-substituted alkenyl succinimides can be prepared by
reacting maleic anhydride with an olefinic hydrocarbon followed by
reacting the resulting alkenyl succinic anhydride with the alkylene
polyamine. The alkenyl radical, is preferably derived from a
polymer prepared from an olefin monomer containing from 2 to 5
carbon atoms. Thus, the alkenyl radical is obtained by polymerizing
an olefin containing from 2 to 5 carbon atoms to form a hydrocarbon
having a molecular weight ranging from about 450 to 3000. Such
olefin monomers are exemplified by ethylene, propylene, 1-butene,
2-butene, isobutene, and mixtures thereof.
[0091] In a preferred aspect, the alkenyl succinimide may be
prepared by reacting a polyalkylene succinic anhydride with an
alkylene polyamine. The polyalkylene succinic anhydride is the
reaction product of a polyalkylene (preferably polyisobutene) with
maleic anhydride. One can use conventional polyisobutene, or high
methylvinylidene polyisobutene in the preparation of such
polyalkylene succinic anhydrides. One can use thermal,
chlorination, free radical, acid catalyzed, or any other process in
this preparation. Examples of suitable polyalkylene succinic
anhydrides are thermal PIBSA (polyisobutenyl succinic anhydride)
described in U.S. Pat. No. 3,361,673; chlorination PIBSA described
in U.S. Pat. No. 3,172,892; a mixture of thermal and chlorination
PIBSA described in U.S. Pat. No. 3,912,764; high succinic ratio
PIBSA described in U.S. Pat. No. 4,234,435; PolyPIBSA described in
U.S. Pat. Nos. 5,112,507 and 5,175,225; high succinic ratio
PolyPIBSA described in U.S. Pat. Nos. 5,565,528 and 5,616,668; free
radical PIBSA described in U.S. Pat. Nos. 5,286,799, 5,319,030, and
5,625,004; PIBSA made from high methylvinylidene polybutene
described in U.S. Pat. Nos. 4,152,499, 5,137,978, and 5,137,980;
high succinic ratio PIBSA made from high methylvinylidene
polybutene described in European Patent Application Publication No.
EP 355 895; terpolymer PIBSA described in U.S. Pat. No. 5,792,729;
sulfonic acid PIBSA described in U.S. Pat. No. 5,777,025 and
European Patent Application Publication No. EP 542 380; and
purified PIBSA described in U.S. Pat. No. 5,523,417 and European
Patent Application Publication No. EP 602 863. The disclosures of
each of these documents are incorporated herein by reference in
their entirety. The polyalkylene succinic anhydride is preferably a
polyisobutenyl succinic anhydride. In one preferred embodiment, the
polyalkylene succinic anhydride is a polyisobutenyl succinic
anhydride having a number average molecular weight of at least 450,
more preferably at least 900 to about 3000 and still more
preferably from at least about 900 to about 2300.
[0092] In another preferred embodiment, a mixture of polyalkylene
succinic anhydrides are employed. In this embodiment, the mixture
preferably comprises a low molecular weight polyalkylene succinic
anhydride component and a high molecular weight polyalkylene
succinic anhydride component. More preferably, the low molecular
weight component has a number average molecular weight of from
about 450 to below 1000 and the high molecular weight component has
a number average molecular weight of from 1000 to about 3000. Still
more preferably, both the low and high molecular weight components
are polyisobutenyl succinic anhydrides. Alternatively, various
molecular weights polyalkylene succinic anhydride components can be
combined as a dispersant as well as a mixture of the other above
referenced dispersants as identified above.
[0093] The polyalkylene succinic anhydride can also be incorporated
with the detergent which is anticipated to improve stability and
compatibility of the detergent mixture. When employed with the
detergent it can comprise from 0.5 to 5 percent by weight of the
detergent mixture and preferably from about 1.5 to 4 weight
percent.
[0094] The alkylene amines include principally methylene amines,
ethylene amines, butylene amines, propylene amines, pentylene
amines, hexylene amines, heptylene amines, octylene amines, other
polymethylene amines and also the cyclic and the higher homologs of
such amines as piperazine and amino alkyl-substituted piperazines.
They are exemplified specifically by ethylene diamine, triethylene
tetraamine, propylene diamine, decamethyl diamine, octamethylene
diamine, diheptamethylene triamine, tripropylene tetraamine,
tetraethylene pentamine, trimethylene diamine, pentaethylene
hexamine, ditrimethylene triamine,
2-heptyl-3-(2-aminopropyl)-imidazoline, 4-methyl imidazoline,
N,N-dimethyl-1,3-propane diamine, 1,3-bis(2-aminoethyl)imidazoline,
1-(2-aminopropyl)-piperazine, 1,4-bis(2-aminoethyl)piperazine and
2-methyl-1-(2-aminobutyl)piperazine. Higher homologs such as are
obtained by condensing two or more of the above-illustrated
alkylene amines likewise are useful.
[0095] The ethylene amines are especially useful. They are
described in some detail under the heading "Ethylene Amines" in
Encyclopedia of Chemical Technology, Kirk-Othmer, Vol. 5, pp.
898-905 (Interscience Publishers, New York, 1950). The term
"ethylene amine" is used in a generic sense to denote a class of
polyamines conforming for the most part to the structure
H.sub.2N(CH.sub.2CH.sub.2NH).sub.tH wherein t is an integer from 1
to 10. Thus, it includes, for example, ethylene diamine, diethylene
triamine, triethylene tetraamine, tetraethylene pentamine,
pentaethylene hexamine, and the like.
[0096] The individual alkenyl succinimides used in the alkenyl
succinimide composition of the present invention can be prepared by
conventional processes, such as disclosed in U.S. Pat. Nos.
2,992,708; 3,018,250; 3,018,291; 3,024,237; 3,100,673; 3,172,892;
3,202,678; 3,219,666; 3,272,746; 3,361,673; 3,381,022; 3,912,764;
4,234,435; 4,612,132; 4,747,965; 5,112,507; 5,241,003; 5,266,186;
5,286,799; 5,319,030; 5,334,321; 5,356,552; 5,716,912, the
disclosures of which are all hereby incorporated by reference in
their entirety for all purposes.
[0097] Also included within the term "alkenyl succinimides" are
post-treated succinimides such as post-treatment processes
involving borate or ethylene carbonate disclosed by Wollenberg, et
al., U.S. Pat. No. 4,612,132; Wollenberg, et al., U.S. Pat. No.
4,746,446; and the like as well as other post-treatment processes
each of which are incorporated herein by reference in its entirety.
Preferably, the carbonate-treated alkenyl succinimide is a
polybutene succinimide derived from polybutenes having a molecular
weight of 450 to 3000, preferably from 900 to 2500, more preferably
from 1300 to 2300, and preferably from 2000 to 2400, as well as
mixtures of these molecular weights. Preferably, it is prepared by
reacting, under reactive conditions, a mixture of a polybutene
succinic acid derivative, an unsaturated acidic reagent copolymer
of an unsaturated acidic reagent and an olefin, and a polyamine,
such as taught in U.S. Pat. No. 5,716,912 incorporated herein by
reference.
[0098] The alkenyl succinimide can be a modified alkenyl
succinimide which is obtained by after-treatment using a boric
acid, an alcohol, an aldehyde, a ketone, an alkylphenol, a cyclic
carbonate, an organic acid, or the like. Preferable modified
succinimides are borated alkenyl succinimides which are produced by
after-treatment using boric acid or a boron-containing compound.
The borated succinimides are preferred because of their high
thermal and oxidation stability.
[0099] Preferably, the alkenyl succinimide component comprises from
1 to 20 weight percent, preferably 2 to 12 weight percent, and more
preferably 4 to 8 weight percent of the weight of the lubricant
composition. Suitable nitrogen containing dispersants may be
employed in an amount within a range of 0.01 to 0.3 mass % in terms
of nitrogen content.
[0100] Lubricating Oil and Lubricating Compositions
[0101] The lubricating oil compositions of the present invention
can be conveniently prepared by simply blending or mixing
hydrocarbyl diol and the overbased detergent mixtures of the
present invention, with an oil of lubricating viscosity (base oil).
The compounds of the invention may also be preblended as a
concentrate or package with various other additives in the
appropriate ratios to facilitate blending of a lubricating
composition containing the desired concentration of additives. The
compounds of the present invention are blended with base oil a
concentration at which they provide improved fuel economy and are
both soluble in the oil and compatible with other additives in the
desired finished lubricating oil. Compatibility in this instance
generally means that the present compounds as well as being oil
soluble in the applicable treat rate also do not cause other
additives to precipitate under normal conditions. Suitable oil
solubility/compatibility ranges for a given compound of lubricating
oil formulation can be determined by those having ordinary skill in
the art using routine solubility testing procedures. For example,
precipitation from a formulated lubricating oil composition at
ambient conditions (about 20.degree. C.-25.degree. C.) can be
measured by either actual precipitation from the oil composition or
the formulation of a "cloudy" solution which evidences formation of
insoluble wax particles.
[0102] The lubricating oil, or base oil, used in the lubricating
oil compositions of the present invention are generally tailored to
the specific use e.g. engine oil, gear oil, industrial oil, cutting
oil, etc. For example, where desired as a crankcase engine oil, the
base oil typically will be a mineral oil or synthetic oil of
viscosity suitable for use in the crankcase of an internal
combustion engine such as gasoline engines and diesel engines which
include marine engines. Crankcase lubricating oils ordinarily have
a viscosity of about 1300 cSt at 0.degree. F. to 24 cSt at
210.degree. F. (99.degree. C.) the lubricating oils may be derived
from synthetic or natural sources. Natural oils include animal oils
and vegetable oils (e.g. castor oil, lard oil) as well as mineral
oil. Mineral oil for use as the base oil in this invention includes
paraffinic, naphthenic and other oils that are ordinarily used in
lubricating oil compositions, including solvent treated, hydro
treated or oils from Fisher-Tropsch processes. Preferred oils of
lubricating viscosity used in this invention should have a
viscosity index of at least 95, preferably at least 100. The
preferred are selected from API Category oils Group I through Group
IV and preferably from Group II, III and IV or mixtures thereof
optionally blended with Group I. Synthetic oils include both
hydrocarbon synthetic oils and synthetic esters. Useful synthetic
hydrocarbon oils include liquid polymers of alpha olefins having
the proper viscosity. Especially useful are the hydrogenerated
liquid oligomers of C.sub.6 to C.sub.12 alpha olefins such as
1-decene trimer. Likewise, alkyl benzenes of proper viscosity such
as didodecyl benzene can be used. Useful synthetic esters include
the esters of both monocarboxylic acid and polycarboxylic acids as
well as monohydroxy alkanols and polyols. Typical examples are
didodecyl adipate, pentaerythritol tetracaproate, di-2-ethylhexyl
adipate, dilaurylsebacate and the like. Complex esters prepared
from mixtures of mono and dicarboxylic acid and mono and dihydroxy
alkanols can also be used. Blends of various mineral oils,
synthetic oils and minerals and synthetic oils may also be
advantageous, for example to provide a given viscosity or viscosity
range. In general the base oils or base oil mixtures for engine oil
are preselected so that the final lubricating oil, containing the
various additives, including the present fuel economy additive
composition, has a viscosity at 100.degree. C. of 4 to 22
centistokes.
[0103] Typically the lubricating oil composition will contain a
variety of compatible additives desired to impart various
properties to the finished lubricating oil composition depending on
the particular end use and base oils used. Such additives include
supplemental neutral and basic detergents such as natural and
overbased organic sulfonates and normal and overbased phenates and
salicylates, dispersants, and/or ashless dispersants. Also other
additives such as antiwear agents, friction modifiers, rust
inhibitors, foam inhibitors, pour point dispersants, antioxidants,
including the so called viscosity index (VI) improvers, dispersant
VI improvers and, as noted above, other corrosion or wear
inhibitors.
[0104] Preferably a minor amount of antiwear agent, a metal
dihydrocarbyl dithiophosphate is added to the lubricant
composition. The metal is preferably zinc. The
dihydrocarbyldithiophosphate may be present in amount of 0.1 to 2.0
mass percent but typically low phosphorous compositions are desired
so the dihydrocarbyldithiophosphate is employed at a dosage of less
than 0.1 mass % measured as phosphorus level in the lubricating oil
composition. Preferably, zinc dialkylthiophosphate (ZDDP) is used.
This provides antioxidant and antiwear properties to the
lubricating composition. Such compounds may be prepared in
accordance with known techniques by first forming a
dithiophosphoric acid, usually by reaction of an alcohol or a
phenol with P2S5 and then neutralizing the dithiophosphoric acid
with a suitable zinc compound. Mixtures of alcohols may be used
including mixtures of primary and secondary alcohols. Examples of
such alcohols include, but are not restricted to the following
list: iso-propanol, iso-octanol, 2-butanol, methyl isobutyl
carbinol (4-methyl-1-pentane-2-ol), 1-pentanol, 2-methyl butanol,
and 2-methyl-1-propanol. The hydrocarbyl groups can be a primary,
secondary, or mixtures thereof, e.g. the compounds may contains
primary and/or secondary alkyl groups derived from primary or
secondary carbon atoms. Moreover, when employed, there is
preferably at least 50, more preferably 75 or more, most preferably
85 to 100, mass % secondary alkyl groups; an example is a ZDDP
having 85 mass % secondary alkyl groups and 15 mass % primary alkyl
groups, such as a ZDDP made from 85 mass % butan-2-ol and 15 mass %
iso-octanol. Even more preferred is a ZDDP derived from derived
from sec-butanol and methylisobutylcarbinol and most preferably
wherein the sec-butanol is 75 mole percent.
[0105] The metal dihydrocarbyldithiophosphate provides most if not
all, of the phosphorus content of the lubricating oil composition.
Amounts are present in the lubricating oil composition to provide a
phosphorus content, expressed as mass % elemental phosphorus, of
0.10 or less, preferably 0.08 or less, and more preferably 0.075 or
less, such as in the range of 0.025 to 0.07.
[0106] Oxidation inhibitors or antioxidants reduce the tendency of
base stocks to deteriorate in service, which deterioration can be
evidenced by the products of oxidation such as sludge and
varnish-like deposits on the metal surfaces and by viscosity
growth. The lubricating oil composition of the present invention
further contains, in an amount that is within a range of 0.1 to 7
mass %, at least one antioxidant selected from the group consisting
of phenol compounds (phenol antioxidants), amine compounds (amine
antioxidants), and molybdenum compounds (molybdenum
antioxidants).
[0107] A hindered phenol compound is generally used as the phenol
antioxidant, and a diaryl amine compound is generally used as the
amine antioxidant. Hindered phenol antioxidants and diaryl amine
antioxidants are both also effective in improving high-temperature
detergency. Diaryl amine antioxidants in particular have a base
value derived from nitrogen and are effective in improving
high-temperature detergency. On the other hand, hindered phenol
antioxidants are effective in preventing oxidative degradation.
[0108] Examples of hindered phenol antioxidants are
2,6-di-t-butyl-p-cresol, 4,4'-methylenebis(2,6-di-t-butylphenol),
4,4'-methylenebis(6-t-butyl-o-cresol),
4,4'-isoropylidenebis(2,6)\-di-t-butylphenol),
4,4'-bis(2,6-di-t-butylphenol),
2,2'-methylenebis(4-methyl-6-t-butylphenol),
4,4'-thiobis(2-methyl-6-t-butylphenol),
2,2-thiodiethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],
octyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, octadecyl
3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and octyl
3-(5-t-butyl-4-hydroxy-3-methylphenyl)propionate.
[0109] Examples of amine antioxidants are C4-9 mixed alkyl diphenyl
amines, p,p'-dioctyldiphenylamine, phenyl-.alpha.-naphthylamine,
phenyl-.beta.-naphthylamine, alkylated-.alpha.-naphthylamine, and
alkylated-phenyl-.alpha.-naphthylamine.
[0110] Examples of molybdenum antioxidants are oxymolybdenum
complexes of basic nitrogen compounds. Examples of preferred
oxymolybdenum complexes of basic nitrogen compounds are
oxymolybdenum complexes of succinimide and oxymolybdenum complexes
of carbonamide. Oxymolybdenum complexes of basic nitrogen compounds
can be produced using the following method, for instance. A
molybdenum complex is produced by reacting an acidic molybdenum
compound or salt thereof with a basic nitrogen compound, such as a
succinimide, carbonamide, hydrocarbon monoamine, hydrocarbon
polyamine, Mannich hydrochloric acid, phosphonamide,
thiophosphonamide, phosphoric amide, dispersion-type viscosity
index-improving agent (or a mixture thereof), while maintaining the
reaction temperature at 120.degree. C. or lower.
[0111] Moreover, it is also possible to use a molybdenum-containing
compound other than an oxymolybdenum complex of a basic nitrogen
compound in place of the oxymolybdenum complex of the basic
nitrogen compound, or in combination with the oxymolybdenum complex
of a basic nitrogen compound. Examples of the combined
molybdenum-containing compounds that can be used are sulfurized
oxymolybdenum dithiocarbamates and sulfurized oxymolybdenum
dithiophosphates.
[0112] The phenol antioxidant (particularly hindered phenol
antioxidant), amine antioxidant (particularly diaryl amine
antioxidant), and molybdenum antioxidant (particularly
oxymolybdenum complex of basic nitrogen compound) can be used
alone, or they can be used as an arbitrary combination with one
another as desired. It is also possible to use these in combination
with an oil-soluble antioxidant.
[0113] Additional friction modifiers optionally may be employed and
may include such compounds as aliphatic amines or ethoxylated
aliphatic amines, aliphatic fatty acid amides, aliphatic carboxylic
acids, aliphatic carboxylic esters of polyols such as glycerol
esters of fatty acid as exemplified by glycerol oleate, boric
esters of glycerol fatty acid monoesters, aliphatic carboxylic
ester-amides, aliphatic phosphonates, aliphatic phosphates,
aliphatic thiophosphonates, aliphatic thiophosphates, etc., wherein
the aliphatic group usually contains above about eight carbon atoms
so as to render the compound suitably oil soluble. Representative
examples of suitable friction modifiers are found in U.S. Pat. No.
3,933,659 which discloses fatty acid esters and amides; U.S. Pat.
No. 4,105,571 which discloses glycerol esters of dimerized fatty
acids; U.S. Pat. No. 4,702,859 which discloses esters of
carboxyclic acids and anhydrides with alkanols; U.S. Pat. No.
4,530,771 which is a preferred borated glycerol monooleate
comprising esters constituted with a glycerol, fatty acid and a
boric acid, said ester having a positive amount up to 2.0 moles of
a carboxylic acid residue comprising a saturated or unsaturated
alkyl group having 8 to 24 carbon atoms and 1.5 to 2.0 moles of a
glycerol residue, both per unit mole of a boric acid residue on
average of the boric esters used singly or in combination, molar
proportion between said carboxylic acid residue and said glycerol
residue being that the glycerol residue is 1.2 moles or more based
on 1 mole of the carboxylic acid residue; U.S. Pat. No. 3,779,928
which discloses alkane phosphonic acid salts; U.S. Pat. No.
3,778,375 which discloses reaction products of a phosphonate with
an oleamide; and U.S. Pat. No. 3,932,290 which discloses reaction
products of di-(lower alkyl) phosphites and epoxides. The
disclosures of the above references are herein incorporated by
reference. Examples of nitrogen containing friction modifiers,
include, but are not limited to, imidazolines, amides, amines,
alkoxylated amines, alkoxylated ether amines, amine oxides,
amidoamines, nitriles, betaines, quaternary amines, imines, amine
salts, amino guanadine, alkanolamides, and the like. Such friction
modifiers can contain hydrocarbyl groups that can be selected from
straight chain, branched chain or aromatic hydrocarbyl groups or
admixtures thereof, and may be saturated or unsaturated.
Hydrocarbyl groups are predominantly composed of carbon and
hydrogen but may contain one or more hetero atoms such as sulfur or
oxygen. Preferred hydrocarbyl groups range from 12 to 25 carbon
atoms and may be saturated or unsaturated. More preferred are those
with linear hydrocarbyl groups.
[0114] Such friction modifier is preferably an oil soluble organic
friction modifier incorporated in the lubricating oil composition
in an amount of from about 0.02 to 2.0 wt. % of the lubricating oil
composition. Preferably, from 0.05 to 1.0, more preferably from 0.1
to 0.5 wt. % of the friction modifier is used.
[0115] The lubricating composition of the present invention may
also contain a viscosity index improver or VII. Viscosity Index
Improver. Examples of the viscosity index improvers are poly-(alkyl
methacrylate), ethylene-propylene copolymer, styrene-butadiene
copolymer, and polyisoprene. Viscosity index improvers of
dispersant type (having increased dispersancy) or multifunction
type are also employed. These viscosity index improvers can be used
singly or in combination. The amount of viscosity index improver to
be incorporated into an engine oil varies with desired viscosity of
the compounded engine oil, and generally in the range of 0.5-20 wt.
% per total amount of the engine oil.
[0116] The engine oil compositions have outstanding Noack
volatilities, as determined by ASTM D5800. Preferably, the Noack
volatility of the engine oil composition is less than wt % loss,
less than 13 wt % loss, or less than 11 wt % loss.
[0117] The engine oil compositions have outstanding CCS viscosities
at -35.degree. C., as determined by ASTM D5293. Preferably, the CCS
viscosity of the engine oil composition is less than 5200 mPas,
less than 5000 mPas, less than 4000 mPas, less than 3800 mPas, less
than 3500 mPas, less than 3000 mPas, or less than 2500 mPas.
[0118] The engine oil compositions have outstanding
high-temperature, high-shear (HTHS) viscosities at 150.degree. C.,
as determined by ASTM D4683. Preferably, the HTHS viscosity of the
engine oil composition at 150.degree. C. is less than 2.9 mPas,
less than 2.6 mPas, less than 2.4 mPas, less than 2.3 mPas, less
than 2.0 less than mPas, 1.9 mPas, less than 1.8 mPas, or less than
1.5 mPas.
[0119] The following examples are presented to illustrate specific
embodiments of this invention and are not to be construed in any
way as limiting the scope of the invention.
EXAMPLES
[0120] The invention will be further illustrated by the following
examples, which set forth particularly advantageous embodiments.
The type and quantities of performance additives used in
combination with the instant invention in lubricating oil
compositions are not limited but the examples shown herein as
illustrations.
Examples 1-4 and Comparative Examples A-D
[0121] Lubricating oil compositions were prepared by adding the
below mentioned additive components to the base oil to give the
formulations set forth in Tables 1 and 2. The lubricating oil
compositions for Examples 1-4 are according to the invention, while
Comparative Examples A-D are offered as comparison and are not of
the invention. Examples 1-3 and Comparative Examples A-C were
formulated targeting an SAE viscosity grade of 0W-20 (as defined in
SAE J300, January 2009 version). They have a kinematic viscosity of
7.7-7.8 mm.sup.2/s at 100.degree. C. Example 4 and Comparative
Example D were formulated targeting an SAE viscosity grade of 0W-4.
They have a kinematic viscosity of 3.1 mm.sup.2/s at 100.degree.
C.
[0122] Base Oil-- [0123] a) Examples 1-3 and Comparative Examples
A-C: Mineral base oil (kinematic viscosity for 4.2 mm.sup.2/s at
100.degree. C., viscosity index of 130) prepared via vacuum
distillation, isodewaxing and hydrofinishing. [0124] b) Example 4
and Comparative Example D: Mineral base oil (kinematic viscosity
for 3.1 mm.sup.2/s at 100.degree. C., viscosity index of 112)
prepared via vacuum distillation, isodewaxing and
hydrofinishing.
[0125] Additives:
[0126] Dispersant--Ashless, nitrogen containing, succinimide
dispersant with nitrogen content of 1.0 wt %
[0127] Metal Containing Detergent-- [0128] a) Overbased alkaline
earth metal alkylhydroxybenzoate A: Calcium with TBN of 170 and
metal ratio of 2.3, C14-18 alkyl groups [0129] b) Overbased
alkaline earth metal alkylhydroxybenzoate B: Calcium with TBN of
230 and metal ratio of 4.0, C20-28 alkyl groups [0130] c) Overbased
alkaline earth metal alkylhydroxybenzoate C: Calcium with TBN of
320 and metal ratio of 8.0, C20-28 alkyl groups [0131] d) Overbased
Sulfonate A: Calcium sulfonate with TBN of 425 and metal ratio of
17.9, C20-28 alkyl groups [0132] e) Low Overbased Sulfonate B:
Calcium sulfonate with TBN of 17 and metal ratio of 1.5, C20-28
alkyl groups
[0133] Friction Modifier-- [0134] a) FM A: Vicinal diol friction
modifier made from a mixture of 16 and 18 carbon alpha olefins
[0135] b) FM B: Borated glycerol monooleate friction modifier
[0136] Zinc Wear Inhibitor--Mixture of zinc
dialkyldithiophosphates
[0137] Oxidation Inhibitor--Mixture of diphenylamine based aminic
antioxidant and a molybdenum succinimide complex with Mo=5.5 wt %,
S=0.2 wt %, N=1.6 wt %
[0138] Viscosity Index Improver--Polymethacrylate viscosity index
improver used in 0W-20 formulations. No VII was used in 0W-4
oils.
[0139] HFRR Friction Test
[0140] The friction performance of the lubricating oil compositions
of Examples 1-3 was evaluated using a High Frequency Reciprocating
Rig (HFRR), and compared to the friction performance of the
lubricating oil composition of Comparative Examples A-C.
[0141] The HFRR test rig is an industry recognized tribometer for
determining lubricant performance. The PCS instrument uses an
electromagnetic vibrator to oscillate a specimen (the ball) over a
small amplitude while pressing it against a fixed specimen (a flat
disk). The amplitude and frequency of the oscillation and the load
are variable. The frictional force between the ball and flat and
the electrical contact resistance (ECR) are measured. The flat,
stationary specimen is held in a bath, to which the lubricating oil
is added, and can be heated. In this method, a 2 mL sample is
placed in the test reservoir of an HFRR and adjusted to a standard
temperature. When the sample temperature has stabilized, a vibrator
arm holding a non-rotating steel ball is lowered until it contacts
a test disk completely submerged in the sample. The ball is caused
to rub against the disk. For this test, the tribometer was set up
to run at 20 Hz for 60 minutes, using 6 mm ball on flat specimens
of 52100 steel. The load was 1 kg and temperature was 120.degree.
C. In this test, a smaller coefficient of friction corresponds to
less friction between the ball and disk. The formulations for
Examples 1-3 and Comparative Examples A-C and their respective HFRR
friction performance data are presented in Table 1.
TABLE-US-00001 TABLE 1 HFRR Friction Performance Example 1 Example
2 Example 3 Comp. A Comp. B Comp. C Dispersant 300 ppm N 300 ppm N
300 ppm N 300 ppm N 300 ppm N 300 ppm N Overbased calcium 0.96 0.96
0.96 2.9 2.9 alkylhydroxybenzoate A MR = 2.3 Overbased calcium 0.49
alkylhydroxybenzoate B MR = 4.0 Overbased calcium 1.1 0.70
alkylhydroxybenzoate C MR = 8.0 Sulfonate A MR = 0.76 1.0 17.9
Sulfonate B 0.77 0.77 0.77 0.77 0.77 0.77 ZnDTP 770 ppm P 770 ppm P
770 ppm P 770 ppm P 770 ppm P 770 ppm P Oxidation Inhibitor 1.6 1.6
1.6 1.6 1.6 1.6 FM A 1.0 1.0 1.0 1.0 1.0 0 Friction 0.095 0.095
0.094 0.099 0.100 0.114
[0142] Unless otherwise indicated all additive values are given as
weight percent of the fully formulated oil. Dispersant values are
given as ppm of nitrogen supplied by the dispersant. ZnDTP levels
are indicated as ppm phosphorus from the ZnDTP.
[0143] The test results set forth in Table 1 indicate that the
lubricating compositions formulated according to the invention show
improved frictional performance over those of Comparative Examples
A-C.
[0144] Motored Friction Torque Test
[0145] A motored friction torque test was used to evaluate the
frictional performance under boundary lubrication conditions of
Example 4 and Comparative Example D.
[0146] The crank shaft of a gasoline engine (inline 4 cylinder
engine, 1.8 L, roller type valve system) was rotated by means of an
electric motor connected via a torque meter and the running torque
was monitored. The oil temperature was maintained at 100.degree. C.
The test was carried out at a rotational rate of 550 rpm for 150
seconds. The torques were continuously monitored during the period
from 30 seconds after start of test to 120 seconds. An average
torque value was calculated from the monitored torque values.
Independently, a reference oil (SAE viscosity grade 0W-20,
kinematic viscosity at 100.degree. C. of 8.9 mm.sup.2/s) was
prepared. Percentage of change in frictional torque, for Example 4
and Comparative Example D were calculated using the 0W-20 average
torque value as a reference. The formulations of Example 4 and
Comparative Example D as well as their percent change in frictional
torque with regards to the 0W-20 reference oil are presented in
Table 2.
TABLE-US-00002 TABLE 2 Motored Frictional Torque Test Example 4
Comp. D Dispersant 300 ppm N 300 ppm N Overbased calcium 0.96 0.96
alkylhydroxybenzoate A MR = 2.3 Overbased calcium 0.49 0.49
alkylhydroxybenzoate B MR = 4.0 Overbased calcium 0.70 0.70
alkylhydroxybenzoate C MR = 8.0 Sulfonate B 0.77 0.77 ZnDTP 770 ppm
P 770 ppm P Oxidation Inhibitor 1.6 1.6 FM A 1.0 0 FM B 0 1.0 %
Change -2.2 2.9
[0147] Unless otherwise indicated all additive values are given as
weight percent of the fully formulated oil. Dispersant values are
given as ppm of nitrogen supplied by the dispersant. ZnDTP levels
are indicated as ppm phosphorus from the ZnDTP.
[0148] The test results set forth in Table 2 indicate that the
lubricating composition formulated according to the invention shows
improved frictional performance under boundary conditions over that
of Comparative Example D. Comparative Example D, formulated with a
borated glycerol monooleate friction modifier shows increased
friction over the 0W-20 reference oil. Example 4 formulated with
the friction modifier and detergent system of the invention shows
decreased friction.
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