U.S. patent application number 15/452804 was filed with the patent office on 2018-09-13 for low viscosity lubricating oil composition.
The applicant listed for this patent is Chevron Japan Ltd., Chevron Oronite Company LLC. Invention is credited to Koichi Kubo, John Robert Miller, Hitoshi Ohkubo, Isao Tanaka.
Application Number | 20180258365 15/452804 |
Document ID | / |
Family ID | 63446386 |
Filed Date | 2018-09-13 |
United States Patent
Application |
20180258365 |
Kind Code |
A1 |
Ohkubo; Hitoshi ; et
al. |
September 13, 2018 |
LOW VISCOSITY LUBRICATING OIL COMPOSITION
Abstract
A lubricating oil composition having a high temperature high
shear (HTHS) viscosity at 150.degree. C. in a range of about 1.3 to
about 2.3 cP is disclosed. The composition comprises (a) a major
amount of an oil of lubricating viscosity having a kinematic
viscosity at 100.degree. C. in a range of 1.5 to 6.0 mm.sup.2/s;
(b) an organomolybdenum compound providing 200 to 1500 ppm by
weight of molybdenum to the lubricating oil composition; (c) a
calcium-containing detergent providing 750 to 3000 ppm by weight of
calcium to the lubricating oil composition; (d) a
magnesium-containing detergent providing 200 to 1500 ppm by weight
of magnesium to the lubricating oil composition; and (e) a
viscosity modifier having a PSSI of 30 or less.
Inventors: |
Ohkubo; Hitoshi;
(Makinohara, JP) ; Kubo; Koichi; (Yokohama,
JP) ; Tanaka; Isao; (Makinohara, JP) ; Miller;
John Robert; (San Rafael, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chevron Japan Ltd.
Chevron Oronite Company LLC |
San Ramon
San Ramon |
CA
CA |
US
US |
|
|
Family ID: |
63446386 |
Appl. No.: |
15/452804 |
Filed: |
March 8, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2030/42 20200501;
C10M 2215/28 20130101; C10N 2040/255 20200501; C10N 2030/43
20200501; C10N 2030/52 20200501; C10N 2030/02 20130101; C10N
2030/06 20130101; C10N 2020/02 20130101; C10N 2030/04 20130101;
C10M 2207/262 20130101; C10N 2030/10 20130101; C10M 2219/068
20130101; C10M 2203/1025 20130101; C10M 2227/09 20130101; C10M
2207/28 20130101; C10M 2215/02 20130101; C10M 2219/044 20130101;
C10M 169/048 20130101; C10N 2040/25 20130101; C10M 2207/10
20130101; C10M 2223/045 20130101; C10M 2205/0285 20130101; C10M
2215/064 20130101; C10N 2010/04 20130101; C10M 2209/084 20130101;
C10N 2030/74 20200501; C10M 2227/066 20130101; C10M 2219/046
20130101; C10M 2207/144 20130101; C10M 2215/08 20130101; C10M
2223/042 20130101; C10M 2215/28 20130101; C10N 2060/06 20130101;
C10M 2215/28 20130101; C10N 2060/14 20130101; C10M 2219/044
20130101; C10N 2010/04 20130101; C10M 2207/262 20130101; C10N
2010/04 20130101; C10M 2219/046 20130101; C10N 2010/04 20130101;
C10M 2223/045 20130101; C10N 2010/04 20130101; C10M 2227/09
20130101; C10N 2010/12 20130101; C10M 2219/068 20130101; C10N
2010/12 20130101; C10M 2223/042 20130101; C10N 2010/12 20130101;
C10M 2207/10 20130101; C10N 2010/12 20130101; C10M 2207/28
20130101; C10N 2010/12 20130101; C10M 2215/02 20130101; C10N
2010/12 20130101; C10M 2215/08 20130101; C10N 2010/12 20130101;
C10M 2227/09 20130101; C10N 2010/12 20130101; C10M 2219/068
20130101; C10N 2010/12 20130101; C10M 2223/042 20130101; C10N
2010/12 20130101; C10M 2207/10 20130101; C10N 2010/12 20130101;
C10M 2207/28 20130101; C10N 2010/12 20130101; C10M 2215/02
20130101; C10N 2010/12 20130101; C10M 2215/08 20130101; C10N
2010/12 20130101; C10M 2219/044 20130101; C10N 2010/04 20130101;
C10M 2207/262 20130101; C10N 2010/04 20130101; C10M 2219/046
20130101; C10N 2010/04 20130101; C10M 2223/045 20130101; C10N
2010/04 20130101; C10M 2215/28 20130101; C10N 2060/06 20130101;
C10M 2215/28 20130101; C10N 2060/14 20130101 |
International
Class: |
C10M 141/08 20060101
C10M141/08; C10M 133/44 20060101 C10M133/44; C10M 135/10 20060101
C10M135/10; C10M 129/54 20060101 C10M129/54; C10M 145/14 20060101
C10M145/14; C10M 139/00 20060101 C10M139/00; C10M 135/18 20060101
C10M135/18 |
Claims
1. A lubricating oil composition having a HTHS viscosity at
150.degree. C. in a range of about 1.3 to about 2.3 cP, comprising:
(a) a major amount of an oil of lubricating viscosity having a
kinematic viscosity at 100.degree. C. in a range of 1.5 to 6.0
mm.sup.2/s; (b) an organomolybdenum compound providing 200 to 1500
ppm by weight of molybdenum to the lubricating oil composition; (c)
one or more calcium-containing detergents providing 750 to 3000 ppm
by weight of calcium to the lubricating oil composition, wherein at
least one of the one or more calcium-containing detergents has a
total base number (TBN) of from 0 to 80 mg KOH/g; (d) a
magnesium-containing detergent providing 200 to 1000 ppm by weight
of magnesium to the lubricating oil composition; and (e) a
viscosity modifier having a PSSI of 30 or less; wherein the
lubricating oil composition is a 0W-8, 0W-12 or 0W-16 SAE viscosity
grade.
2. (canceled)
3. The lubricating oil composition of claim 1, wherein the oil of
lubricating viscosity is a base oil selected from one or more of
API Group II, Group III, Group IV, and Group V.
4. The lubricating oil composition of claim 1, wherein the
organomolybdenum compound is a sulfur-containing organomolybdenum
compound or a non-sulfur-containing organomolybdenum compound.
5. The lubricating oil composition of claim 1, wherein the
organomolybdenum compound is selected from one the group consisting
of molybdenum dithiocarbamates, molybdenum dithiophosphates,
molybdenum carboxylates, molybdenum esters, molybdenum amines,
molybdenum amides, and combinations thereof.
6. The lubricating oil composition of claim 1, wherein the
molybdenum amine is a molybdenum-succinimide complex.
7. The lubricating oil composition of claim 6, wherein the
succinimide is a C.sub.24 to C.sub.350 alkyl or alkenyl
succinimide.
8. The lubricating oil composition of claim 6, wherein the
succinimide is a polyisobutenyl succinimide is a reaction product
of a C.sub.70 to C.sub.128 polyisobutenyl succinic anhydride and a
polyalkylene polyamine selected from triethylenetetramine,
tetraethylenepentamine, and combinations thereof.
9. The lubricating oil composition of claim 1, wherein the
calcium-containing detergent comprises a calcium sulfonate, a
calcium salicylate, and mixtures thereof.
10. The lubricating oil composition of claim 1, wherein the
calcium-containing detergent provides 1200 to 1800 ppm by weight of
calcium to the lubricating oil composition
11. The lubricating oil composition of claim 1, wherein the
magnesium-containing detergent comprises a magnesium sulfonate.
12. The lubricating oil composition of claim 1, wherein the
magnesium-containing detergent provides 200 to 800 ppm by weight of
magnesium to the lubricating oil composition
13. The lubricating oil composition of claim 1, wherein the mass
ratio of calcium metal to magnesium metal is in a range of 1.5 to
3.5.
14. The lubricating oil composition of claim 1, wherein the
viscosity modifier is a polyalkylmethacrylate.
15. The lubricating oil composition of claim 1, which is for an
internal combustion engine selected from a direct injection spark
ignition engine and a port fuel injection spark ignition engine
coupled to an electric motor/battery system in a hybrid
vehicle.
16. The lubricating oil composition of claim 1, wherein the one or
more calcium-containing detergents further includes one or more
overbased calcium salicylate detergents.
17. The lubricating oil composition of claim 16, wherein the
calcium-containing detergent having a TBN of from 0 to 80 mg KOH/g
is a calcium sulfonate detergent.
18. The lubricating oil composition of claim 16, wherein the one or
more calcium-containing detergents further includes a first
overbased calcium salicylate detergent having a TBN of 150 mg KOH/g
or higher and a second overbased calcium salicylate detergent
having a TBN of 250 to 450 mg KOH/g.
19. A lubricating oil composition having a HTHS viscosity at
150.degree. C. in a range of about 1.3 to about 2.3 cP, comprising:
(a) a major amount of an oil of lubricating viscosity having a
kinematic viscosity at 100.degree. C. in a range of 1.5 to 6.0
mm.sup.2/s; (b) an organomolybdenum compound providing 200 to 1500
ppm by weight of molybdenum to the lubricating oil composition; (c)
a calcium-containing detergent providing 750 to 3000 ppm by weight
of calcium to the lubricating oil composition; (d) a
magnesium-containing detergent providing 200 to 1000 ppm by weight
of magnesium to the lubricating oil composition; and (e) a
viscosity modifier having a PSSI of 30 or less; wherein the
lubricating oil composition is a 0W-8, 0W-12 or 0W-16 SAE viscosity
grade; wherein the lubricating oil composition is devoid of any
overbased calcium sulfonate detergent and overbased calcium phenate
detergent.
20. The lubricating oil composition of claim 19, wherein the
calcium-containing detergent comprises a mixture comprising a
neutral calcium sulfonate detergent, a first overbased calcium
salicylate detergent and a second overbased calcium salicylate
detergent.
Description
TECHNICAL FIELD
[0001] The disclosed technology relates to lubricants for internal
combustion engines, particularly those for spark ignition
engines.
BACKGROUND
[0002] Modern engine designs are being developed to improve fuel
economy without sacrificing performance or durability.
Historically, gasoline was port fuel injected (PFI), that is,
injected through the air intake and entering the combustion chamber
via the air intake valve. Gasoline direct injection (GDI) involves
direct injection of gasoline into the combustion chamber.
[0003] Hybrid vehicles and boosted, direct injection engines are
continuing to be introduced in order to improve fuel consumption of
gasoline engines. The introduction of boosted, direct fuel-injected
engines makes it possible to increase torque at low rpm and lower
displacement while maintaining the same output. Consequently, fuel
consumption can be improved and the proportion of mechanical loss
can be reduced. On the other hand, in boosted, direct fuel-injected
engines, the problem of sudden abnormal combustion in the form of
low speed pre-ignition (LSPI) occurs when torque at low rpm is
increased. The occurrence of LSPI places limitations on improvement
of fuel consumption while also causing an increase in mechanical
loss.
[0004] Engine oil is blended with various additives in order to
satisfy various performance requirements. One well known way to
increase fuel economy is to decrease the viscosity of the
lubricating oil. However, this approach is now reaching the limits
of current equipment capabilities and specifications. At a given
viscosity, it is well known that adding organic or organometallic
friction modifiers reduces the surface friction of the lubricating
oil and allows for better fuel economy. However, these additives
often bring with them detrimental effects such as increased deposit
formation, seals impacts, or they out-compete the anti-wear
components for limited surface sites, thereby not allowing the
formation of an anti-wear film, causing increased wear.
[0005] A major challenge in engine oil formulation is
simultaneously achieving high temperature wear, deposit, and
varnish control while also achieving improved fuel economy.
[0006] Despite the advances in lubricant oil formulation
technology, there exists a need for a low viscosity engine oil
lubricant suitable for both hybrid vehicles and direct injection
engines that effectively improves fuel economy while maintaining or
improving friction reduction properties and deposit control.
SUMMARY
[0007] In one aspect, there is provided a lubricating oil
composition having a HTHS viscosity at 150.degree. C. in a range of
about 1.3 to about 2.3 cP, comprising: (a) a major amount of an oil
of lubricating viscosity having a kinematic viscosity at
100.degree. C. in a range of 1.5 to 6.0 mm.sup.2/s; (b) an
organomolybdenum compound providing 200 to 1500 ppm by weight of
molybdenum to the lubricating oil composition; (c) a
calcium-containing detergent providing 750 to 3000 ppm by weight of
calcium to the lubricating oil composition; (d) a
magnesium-containing detergent providing 200 to 1000 ppm by weight
of magnesium to the lubricating oil composition; and (e) a
viscosity modifier having a PSSI of 30 or less.
DETAILED DESCRIPTION
[0008] Various embodiments of the present disclosure provide
lubricating oil compositions suitable for reducing friction in an
engine, particularly spark-ignited, direct injection and/or port
fuel injection engines. The engine may be coupled to an electric
motor/battery system in a hybrid vehicle (e.g., a port fuel
injection spark ignition engine coupled to an electric
motor/battery system in a hybrid vehicle).
Definitions
[0009] In this specification, the following words and expressions,
if and when used, have the meanings given below.
[0010] A "major amount" means in excess of 50 weight % of a
composition.
[0011] A "minor amount" means less than 50 weight % of a
composition, expressed in respect of the stated additive and in
respect of the total mass of all the additives present in the
composition, reckoned as active ingredient of the additive or
additives.
[0012] "Active ingredients" or "actives" refers to additive
material that is not diluent or solvent.
[0013] All percentages reported are weight % on an active
ingredient basis (i.e., without regard to carrier or diluent oil)
unless otherwise stated.
[0014] The abbreviation "ppm" means parts per million by weight,
based on the total weight of the lubricating oil composition.
[0015] Total base number (TBN) was determined in accordance with
ASTM D2896.
[0016] High temperature high shear (HTHS) viscosity at 150.degree.
C. was determined in accordance with ASTM D4863.
[0017] Kinematic viscosity at 100.degree. C. (KV.sub.100) was
determined in accordance with ASTM D445.
[0018] Cold Cranking Simulator (CCS) viscosity at -35.degree. C.
was determined in accordance with ASTM D5293.
[0019] Noack volatility was determined in accordance with ASTM
D5800.
[0020] Boron, calcium, magnesium, molybdenum, phosphorus, sulfur,
and zinc contents were determined in accordance with ASTM
D5185.
[0021] Nitrogen content was determined in accordance with ASTM
D4629.
[0022] All ASTM standards referred to herein are the most current
versions as of the filing date of the present application.
[0023] Oil of Lubricating Viscosity
[0024] The oil of lubricating viscosity (sometimes referred to as
"base stock" or "base oil") is the primary liquid constituent of a
lubricant, into which additives and possibly other oils are
blended, for example to produce a final lubricant (or lubricant
composition). A base oil is useful for making concentrates as well
as for making lubricating oil compositions therefrom, and may be
selected from natural and synthetic lubricating oils and
combinations thereof.
[0025] Natural oils include animal and vegetable oils, liquid
petroleum oils and hydrorefined, solvent-treated mineral
lubricating oils of the paraffinic, naphthenic and mixed
paraffinic-naphthenic types. Oils of lubricating viscosity derived
from coal or shale are also useful base oils.
[0026] Synthetic lubricating oils include hydrocarbon oils such as
polymerized and interpolymerized olefins (e.g., polybutylenes,
polypropylenes, propylene-isobutylene copolymers, chlorinated
polybutylenes, poly(1-hexenes), poly(1-octenes), poly(1-decenes);
alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes,
dinonylbenzenes, di(2-ethylhexyl)benzenes; polyphenols (e.g.,
biphenyls, terphenyls, alkylated polyphenols); and alkylated
diphenyl ethers and alkylated diphenyl sulfides and the
derivatives, analogues and homologues thereof.
[0027] Another suitable class of synthetic lubricating oils
comprises the esters of dicarboxylic acids (e.g., malonic acid,
alkyl malonic acids, alkenyl malonic acids, succinic acid, alkyl
succinic acids and alkenyl succinic acids, maleic acid, fumaric
acid, azelaic acid, suberic acid, sebacic acid, adipic acid,
linoleic acid dimer, phthalic acid) with a variety of alcohols
(e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl
alcohol, ethylene glycol, diethylene glycol monoether, propylene
glycol). Specific examples of these esters include dibutyl adipate,
di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl
phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic
acid dimer, and the complex ester formed by reacting one mole of
sebacic acid with two moles of tetraethylene glycol and two moles
of 2-ethylhexanoic acid.
[0028] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.12 monocarboxylic acids and polyols, and polyol
ethers such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
[0029] The base oil may be derived from Fischer-Tropsch synthesized
hydrocarbons. Fischer-Tropsch synthesized hydrocarbons are made
from synthesis gas containing H.sub.2 and CO using a
Fischer-Tropsch catalyst. Such hydrocarbons typically require
further processing in order to be useful as the base oil. For
example, the hydrocarbons may be hydroisomerized; hydrocracked and
hydroisomerized; dewaxed; or hydroisomerized and dewaxed; using
processes known to those skilled in the art.
[0030] Unrefined, refined and re-refined oils can be used in the
present lubricating oil composition. Unrefined oils are those
obtained directly from a natural or synthetic source without
further purification treatment. For example, a shale oil obtained
directly from retorting operations, a petroleum oil obtained
directly from distillation or ester oil obtained directly from an
esterification process and used without further treatment would be
unrefined oil. Refined oils are similar to the unrefined oils
except they have been further treated in one or more purification
steps to improve one or more properties. Many such purification
techniques, such as distillation, solvent extraction, acid or base
extraction, filtration and percolation are known to those skilled
in the art. Re-refined oils are obtained by processes similar to
those used to obtain refined oils applied to refined oils which
have been already used in service. Such re-refined oils are also
known as reclaimed or reprocessed oils and often are additionally
processed by techniques for approval of spent additive and oil
breakdown products.
[0031] Hence, the base oil which may be used to make the present
lubricating oil composition may be selected from any of the base
oils in Groups I-V as specified in the American Petroleum Institute
(API) Base Oil Interchangeability Guidelines (API Publication
1509). Such base oil groups are summarized in Table 1 below:
TABLE-US-00001 TABLE 1 Base Oil Properties Group.sup.(a)
Saturates.sup.(b), wt. % Sulfur.sup.(c), wt. % Viscosity
Index.sup.(d) Group I <90 and/or >0.03 80 to <120 Group II
.gtoreq.90 .ltoreq.0.03 80 to <120 Group III .gtoreq.90
.ltoreq.0.03 .gtoreq.120 Group IV Polyalphaolefins (PAOs) Group V
All other base stocks not included in Groups I, II, III or IV
.sup.(a)Groups I-III are mineral oil base stocks.
.sup.(b)Determined in accordance with ASTM D2007.
.sup.(c)Determined in accordance with ASTM D2622, ASTM D3120, ASTM
D4294 or ASTM D4927. .sup.(d)Determined in accordance with ASTM
D2270.
[0032] Base oils suitable for use herein are any of the variety
corresponding to API Group II, Group III, Group IV, and Group V
oils and combinations thereof, preferably the Group III to Group V
oils due to their exceptional volatility, stability, viscometric
and cleanliness features.
[0033] The base oil constitutes the major component of the present
lubricating oil composition and is present is an amount ranging
from greater than 50 to 99 wt. % (e.g., 70 to 95 wt. %, or 85 to 95
wt. %).
[0034] The base oil may be selected from any of the synthetic or
natural oils typically used as crankcase lubricating oils for
spark-ignited internal combustion engines. The base oil typically
has a kinematic viscosity at 100.degree. C. in a range of 1.5 to 6
mm.sup.2/s. In the case where the kinematic viscosity at
100.degree. C. of the lubricating base oil exceeds 6 mm.sup.2/s,
low temperature viscosity properties may be reduced, and sufficient
fuel efficiency may not be obtained. At a kinematic viscosity of
1.5 mm.sup.2/s or less, formation of an oil film in a lubrication
place is insufficient; for this reason, lubrication is inferior,
and the evaporation loss of the lubricating oil composition may be
increased.
[0035] Preferably, the base oil has a viscosity index of at least
90 (e.g., at least 95, at least 105, at least 110, at least 115, or
at least 120). If the viscosity index is less than 90, not only
viscosity-temperature properties, heat and oxidation stability, and
anti-volatilization are reduced, but also the coefficient of
friction tends to be increased; and resistance against wear tends
to be reduced.
[0036] Organomolybdenum Compound
[0037] The organomolybdenum compound contains at least molybdenum,
carbon and hydrogen atoms, but may also contain sulfur, phosphorus,
nitrogen and/or oxygen atoms. Suitable organomolybdenum compounds
include molybdenum dithiocarbamates, molybdenum dithiophosphates,
and various organic molybdenum complexes such as molybdenum
carboxylates, molybdenum esters, molybdenum amines, molybdenum
amides, which can be obtained by reacting molybdenum oxide or
ammonium molybdates with fats, glycerides or fatty acids, or fatty
acid derivatives (e.g., esters, amines, amides). The term "fatty"
means a carbon chain having 10 to 22 carbon atoms, typically a
straight carbon chain.
[0038] Molybdenum dithiocarbamate (MoDTC) is an organomolybdenum
compound represented by the following structure (1):
##STR00001##
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently of
each other, linear or branched alkyl groups having from 4 to 18
carbon atoms (e.g., 8 to 13 carbon atoms).
[0039] Molybdenum dithiophosphate (MoDTP) is an organomolybdenum
compound represented by the following structure (2):
##STR00002##
wherein R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are independently of
each other, linear or branched alkyl groups having from 4 to 18
carbon atoms (e.g., 8 to 13 carbon atoms).
[0040] In one embodiment, the molybdenum amine is a
molybdenum-succinimide complex. Suitable molybdenum-succinimide
complexes are described, for example, in U.S. Pat. No. 8,076,275.
These complexes are prepared by a process comprising reacting an
acidic molybdenum compound with an alkyl or alkenyl succinimide of
a polyamine of structure (3) or (4) or mixtures thereof:
##STR00003##
wherein R is a C.sub.24 to C.sub.350 (e.g., C.sub.70 to C.sub.128)
alkyl or alkenyl group; R' is a straight or branched-chain alkylene
group having 2 to 3 carbon atoms; x is 1 to 11; and y is 1 to
10.
[0041] The molybdenum compounds used to prepare the
molybdenum-succinimide complex are acidic molybdenum compounds or
salts of acidic molybdenum compounds. By "acidic" is meant that the
molybdenum compounds will react with a basic nitrogen compound as
measured by ASTM D664 or D2896. Generally, the acidic molybdenum
compounds are hexavalent. Representative examples of suitable
molybdenum compounds include molybdenum trioxide, molybdic acid,
ammonium molybdate, sodium molybdate, potassium molybdate and other
alkaline metal molybdates and other molybdenum salts such as
hydrogen salts, (e.g., hydrogen sodium molybdate), MoOCl.sub.4,
MoO.sub.2Br.sub.2, Mo.sub.2O.sub.3Cl.sub.6, and the like.
[0042] The succinimides that can be used to prepare the
molybdenum-succinimide complex are disclosed in numerous references
and are well known in the art. Certain fundamental types of
succinimides and the related materials encompassed by the term of
art "succinimide" are taught in U.S. Pat. Nos. 3,172,892;
3,219,666; and 3,272,746. The term "succinimide" is understood in
the art to include many of the amide, imide, and amidine species
which may also be formed. The predominant product however is a
succinimide and this term has been generally accepted as meaning
the product of a reaction of an alkyl or alkenyl substituted
succinic acid or anhydride with a nitrogen-containing compound.
Preferred succinimides are those prepared by reacting a
polyisobutenyl succinic anhydride of about 70 to 128 carbon atoms
with a polyalkylene polyamine selected from triethylenetetramine,
tetraethylenepentamine, and mixtures thereof.
[0043] The molybdenum-succinimide complex may be post-treated with
a sulfur source at a suitable pressure and a temperature not to
exceed 120.degree. C. to provide a sulfurized
molybdenum-succinimide complex. The sulfurization step may be
carried out for a period of from about 0.5 to 5 hours (e.g., 0.5 to
2 hours). Suitable sources of sulfur include elemental sulfur,
hydrogen sulfide, phosphorus pentasulfide, organic polysulfides of
formula R.sub.2S.sub.x where R is hydrocarbyl (e.g., C.sub.1 to
C.sub.10 alkyl) and x is at least 3, C.sub.1 to C.sub.10
mercaptans, inorganic sulfides and polysulfides, thioacetamide, and
thiourea.
[0044] The molybdenum-succinimide complex is used in an amount that
provides at least 200 ppm (e.g., 200 to 1500 ppm, 200 to 1100 ppm,
250 to 1500 ppm, 250 to 1100 ppm, or 300 to 1000 ppm) by weight of
molybdenum to the lubricating oil composition.
[0045] Detergent Mixture
[0046] The detergent mixture comprises at least one
calcium-containing detergent and at least one magnesium-containing
detergent.
[0047] 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, phosphorous
acid, phenol, or mixtures thereof. The counterion is typically an
alkaline earth or alkali metal.
[0048] Salts that contain a substantially stoichiometric amount of
the metal are described as neutral salts and have a total base
number (TBN) of from 0 to 80 mg KOH/g. Many compositions are
overbased, containing large amounts of a metal base that is
achieved by reacting an excess of a metal compound (e.g., a metal
hydroxide or oxide) rich an acidic gas (e.g., carbon dioxide).
Useful detergents can be neutral, mildly overbased, or highly
overbased.
[0049] It is desirable for at least some detergent used in the
detergent mixture to be overbased. Overbased detergents help
neutralize acidic impurities produced by the combustion process and
become entrapped in the oil. Typically, the overbased material has
a ratio of metallic ion to anionic portion of the detergent of
1.05:1 to 50:1 (e.g., 4:1 to 25:1) on an equivalent basis. The
resulting detergent is an overbased detergent that will typically
have a TBN of 150 mg KOH/g or higher (e.g., 250 to 450 mg KOH/g or
more). A mixture of detergents of differing TBN can be used.
[0050] Suitable detergents include metal salts of sulfonates,
phenates, carboxylates, phosphates, and salicylates.
[0051] Sulfonates may be prepared from sulfonic acids which are
typically obtained by the sulfonation of alkyl-substituted aromatic
hydrocarbons such as those obtained from the fractionation of
petroleum or by the alkylation of aromatic hydrocarbons. Examples
included those obtained by alkylating benzene, toluene, xylene,
naphthalene, diphenyl or their halogen derivatives. The alkylation
may be carried out in the presence of a catalyst with alkylating
agents having from about 3 to more than 70 carbon atoms. The
alkaryl sulfonates usually contain from about 9 to 80 or more
carbon atoms (e.g., about 16 to 60 carbon atoms) per alkyl
substituted aromatic moiety.
[0052] Phenates can be prepared by reacting an alkaline earth metal
hydroxide or oxide (e.g., CaO, Ca(OH).sub.2, MgO, or Mg(OH).sub.2)
with an alkyl phenol or sulfurized alkylphenol. Useful alkyl groups
include straight or branched chain C.sub.1 to C.sub.30 (e.g.,
C.sub.4 to C.sub.20) alkyl groups, 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 chain. 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 (e.g.,
elemental sulfur, sulfur halides such as sulfur dichloride, and the
like) and then reacting the sulfurized phenol with an alkaline
earth metal base.
[0053] Salicylates may be prepared by reacting a basic metal
compound with at least one carboxylic acid and removing water from
the reaction product. Detergents made from salicylic acid are one
class of detergents prepared from carboxylic acids. Useful
salicylates include long chain alkyl salicylates. One useful family
of compositions is of the following structure (5):
##STR00004##
wherein R'' is a C.sub.1 to C.sub.30 (e.g., C.sub.13 to C.sub.30)
alkyl group; n is an integer from 1 to 4; and M is an alkaline
earth metal (e.g., Ca or Mg).
[0054] 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.
[0055] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0056] Preferred calcium-containing detergents include calcium
sulfonates, calcium phenates, and calcium salicylates, especially
calcium sulfonates, calcium salicylates, and mixtures thereof.
[0057] The calcium-containing detergent may be used in an amount
that provides at least 750 ppm (e.g., 750 to 3000 ppm, 750 to 2000
ppm, 750 to 1800 ppm, 1000 to 3000 ppm, 1000 to 2000 ppm, 1000 to
1800 ppm, 1200 to 3000 ppm, 1200 to 2000 ppm, or 1200 to 1800 ppm)
by weight of calcium to the lubricating oil composition.
[0058] Preferred magnesium-containing detergents include magnesium
sulfonates, magnesium phenates, and magnesium salicylates,
especially magnesium sulfonates.
[0059] The magnesium-containing detergent may be used in an amount
that provides at least 200 ppm (e.g., 200 to 1000 ppm, 200 to 800
ppm, 300 to 1000 ppm, 300 to 800 ppm, 400 to 1000 ppm, or 400 to
800 ppm) by weight of magnesium to the lubricating oil
composition.
[0060] The mass ratio of calcium to magnesium in the lubricating
oil composition is greater than 1 (e.g., 1.5 to 3.5, or 2 to
3).
[0061] Viscosity Modifier
[0062] Viscosity modifiers function to impart high and low
temperature operability to a lubricating oil. The viscosity
modifier used may have that sole function, or may be
multifunctional. Multifunctional viscosity modifiers that also
function as dispersants are also known. Suitable viscosity
modifiers include polyisobutylene, copolymers of ethylene and
propylene and higher alpha-olefins, polymethacrylates,
polyalkylmethacrylates, methacrylate copolymers, copolymers of an
unsaturated dicarboxylic acid and a vinyl compound, interpolymers
of styrene and acrylic esters, and partially hydrogenated
copolymers of styrene/isoprene, styrene/butadiene, and
isoprene/butadiene, as well as the partially hydrogenated
homopolymers of butadiene and isoprene and isoprene/divinylbenzene.
In one embodiment, the viscosity modifier is a
polyalkylmethacrylate. The topology of the viscosity modifier could
include, but is not limited to, linear, branched, hyperbranched,
star, or comb topology.
[0063] Suitable viscosity modifiers have a Permanent Shear
Stability Index (PSSI) of 30 or less (e.g., 10 or less, 5 or less,
or even 2 or less). PSSI is a measure of the irreversible decrease,
resulting from shear, in an oil's viscosity contributed by an
additive. PSSI is determined according to ASTM D6022. The
lubricating oil compositions of the present disclosure display
stay-in-grade capability. Retention of kinematic viscosity at
100.degree. C. within a single SAE viscosity grade classification
by a fresh oil and its sheared version is evidence of an oil's
stay-in-grade capability.
[0064] The viscosity modifier may be used in an amount of from 0.5
to 15.0 wt. % (e.g., 0.5 to 10 wt. %, 0.5 to 5 wt. %, 1.0 to 15 wt.
%, 1.0 to 10 wt. %, or 1.0 to 5 wt. %), based on the total weight
of the lubricating oil composition.
[0065] Lubricating Oil Composition
[0066] The lubricating oil composition may be a multi-grade oil
identified by the viscosity grade descriptor SAE 0W-X, wherein X
represents any one of 8, 12, and 16.
[0067] The lubricating oil composition has a high temperature shear
(HTHS) viscosity at 150.degree. C. of 2.3 cP or less (e.g., 1.0 to
2.6 cP, or 1.3 to 2.3 cP), such as 2.0 cP or less (e.g., 1.0 to 2.0
cP, or 1.3 to 2.3 cP), or even 1.7 cP or less (e.g., 1.0 to 1.7 cP,
or 1.3 to 1.7 cP).
[0068] The lubricating oil composition has a viscosity index of at
least 135 (e.g., 135 to 400, or 135 to 250), at least 150 (e.g.,
150 to 400, 150 to 250), at least 165 (e.g., 165 to 400, or 165 to
250), at least 190 (e.g., 190 to 400, or 190 to 250), or at least
200 (e.g., 200 to 400, or 200 to 250). If the viscosity index of
the lubricating oil composition is less than 135, it may be
difficult to improve fuel efficiency while maintaining the HTHS
viscosity at 150.degree. C. If the viscosity index of the
lubricating oil composition exceeds 400, evaporation properties may
be reduced, and deficits due to insufficient solubility of the
additive and matching properties with a seal material may be
caused.
[0069] The lubricating oil composition has a kinematic viscosity at
100.degree. C. in a range of 3 to 12 mm.sup.2/s (e.g., 3 to 6.9
mm.sup.2/s, 3.5 to 6.9 mm.sup.2/s, or 4 to 6.9 mm.sup.2/s).
[0070] The lubricating oil composition may contain low levels of
phosphorus. The lubricating oil composition may have a phosphorus
content of 0.12 wt. % or less (e.g., 0.10 wt. % or less, 0.04 to
0.12 wt. %, or 0.04 to 0.10 wt. %), expressed as atoms of
phosphorus, based on the total weight of the composition.
[0071] The lubricating oil composition may contain low levels of
sulfur. The lubricating oil composition may have a sulfur content
of 0.5 wt. % or less (e.g., 0.4 wt. % or less, 0.3 wt. % or less,
or 0.2 wt. % or less), expressed as atoms of sulfur, based on the
total weight of the composition.
[0072] Suitably, the present lubricating oil composition may have a
total base number (TBN) of 4 to 15 mg KOH/g (e.g., 5 to 12 mg
KOH/g, 6 to 12 mg KOH/g, or 8 to 12 mg KOH/g).
[0073] Additional Co-Additives
[0074] The present lubricating oil composition may additionally
contain one or more of the other commonly used lubricating oil
performance co-additives including dispersants, antiwear agents,
antioxidants, friction modifiers, corrosion inhibitors, foam
inhibitors, pour point depressants, and others.
[0075] Dispersants
[0076] Dispersants maintain in suspension materials resulting from
oxidation during engine operation that are insoluble in oil, thus
preventing sludge flocculation and precipitation or deposition on
metal parts. Dispersants useful herein include nitrogen-containing,
ashless (metal-free) dispersants known to effective to reduce
formation of deposits upon use in gasoline and diesel engines.
[0077] Suitable dispersants include hydrocarbyl succinimides,
hydrocarbyl succinamides, mixed ester/amides of
hydrocarbyl-substituted succinic acid, hydroxyesters of
hydrocarbyl-substituted succinic acid, and Mannich condensation
products of hydrocarbyl-substituted phenols, formaldehyde and
polyamines. Also suitable are condensation products of polyamines
and hydrocarbyl-substituted phenyl acids. Mixtures of these
dispersants can also be used.
[0078] Basic nitrogen-containing ashless dispersants are well-known
lubricating oil additives and methods for their preparation are
extensively described in the patent literature. Preferred
dispersants are the alkenyl succinimides and succinamides where the
alkenyl-substituent is a long-chain of preferably greater than 40
carbon atoms. These materials are readily made by reacting a
hydrocarbyl-substituted dicarboxylic acid material with a molecule
containing amine functionality. Examples of suitable amines are
polyamines such as polyalkylene polyamines, hydroxy-substituted
polyamines and polyoxyalkylene polyamines.
[0079] Particularly preferred ashless dispersants are the
polyisobutenyl succinimides formed from polyisobutenyl succinic
anhydride and a polyalkylene polyamine such as a polyethylene
polyamine of formula:
NH.sub.2(CH.sub.2CH.sub.2NH).sub.zH
wherein z is 1 to 11. The polyisobutenyl group is derived from
polyisobutene and preferably has a number average molecular weight
(M.sub.n) in a range of 700 to 3000 Daltons (e.g., 900 to 2500
Daltons). For example, the polyisobutenyl succinimide may be a
bis-succinimide derived from a polyisobutenyl group having a
M.sub.n of 900 to 2500 Daltons.
[0080] As is known in the art, the dispersants may be post-treated
(e.g., with a boronating agent or a cyclic carbonate).
[0081] Nitrogen-containing ashless (metal-free) dispersants are
basic, and contribute to the TBN of a lubricating oil composition
to which they are added, without introducing additional sulfated
ash.
[0082] Dispersants may be present at 0.1 to 10 wt. % (e.g., 2 to 5
wt. %) of the lubricating oil composition.
[0083] Antiwear Agents
[0084] Antiwear agents reduce wear of metal parts. Suitable
anti-wear agents include dihydrocarbyl dithiophosphate metal salts
such as zinc dihydrocarbyl dithiophosphates (ZDDP) of formula:
Zn[S--P(.dbd.S)(OR.sup.1)(OR.sup.2)].sub.2
wherein R.sup.1 and R.sup.2 may be the same of different
hydrocarbyl radicals having from 1 to 18 (e.g., 2 to 12) carbon
atoms and including radicals such as alkyl, alkenyl, aryl,
arylalkyl, alkaryl and cycloaliphatic radicals. Particularly
preferred as R.sup.1 and R.sup.2 groups are alkyl groups having
from 2 to 8 carbon atoms (e.g., the alkyl radicals may be ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl,
isopentyl, n-hexyl, isohexyl, 2-ethylhexyl). In order to obtain oil
solubility, the total number of carbon atoms (i.e.,
R.sup.1+R.sup.2) will be at least 5. The zinc dihydrocarbyl
dithiophosphate can therefore comprise zinc dialkyl
dithiophosphates. Preferably, the zinc dialkyl dithiophosphate is a
secondary zinc dialkyl dithiophosphate.
[0085] ZDDP may be present at 3 wt. % or less (e.g., 0.1 to 1.5 wt.
%, or 0.5 to 1.0 wt %) of the lubricating oil composition.
[0086] Antioxidants
[0087] Antioxidants reduce the tendency of mineral oils during to
deteriorate during service. Oxidative deterioration can be
evidenced by sludge in the lubricant, varnish-like deposits on the
metal surfaces, and by viscosity growth. Suitable antioxidants
include hindered phenols, aromatic amines, and sulfurized
alkylphenols and alkali and alkaline earth metals salts
thereof.
[0088] The hindered phenol antioxidant often contains a secondary
butyl and/or a tertiary butyl group as a sterically hindering
group. The phenol group may be further substituted with a
hydrocarbyl group (typically linear or branched alkyl) and/or a
bridging group linking to a second aromatic group. Examples of
suitable hindered phenol antioxidants include
2,6-di-tert-butylphenol; 4-methyl-2,6-di-tert-butylphenol;
4-ethyl-2,6-di-tert-butylphenol; 4-propyl-2,6-di-tert-butylphenol;
4-butyl-2,6-di-tert-butylphenol; and
4-dodecyl-2,6-di-tert-butylphenol. Other useful hindered phenol
antioxidants include 2,6-di-alkyl-phenolic propionic ester
derivatives such as IRGANOX.RTM. L-135 from Ciba and bis-phenolic
antioxidants such as 4,4'-bis(2,6-di-tert-butylphenol) and
4,4'-methylenebis(2,6-di-tert-butylphenol).
[0089] Typical aromatic amine antioxidants have at least two
aromatic groups attached directly to one amine nitrogen. Typical
aromatic amine antioxidants have alkyl substituent groups of at
least 6 carbon atoms. Particular examples of aromatic amine
antioxidants useful herein include 4,4'-dioctyldiphenylamine,
4,4'-dinonyldiphenylamine, N-phenyl-1-naphthylamine,
N-(4-tert-octyphenyl)-1-naphthylamine, and
N-(4-octylphenyl)-1-naphthylamine.
[0090] Antioxidants may be present at 0.01 to 5 wt. % (e.g., 0.1 to
2 wt. %) of the lubricating oil composition.
[0091] Friction Modifiers
[0092] A friction modifier is any material that can alter the
coefficient of friction of a surface lubricated by any lubricant or
fluid containing such material. Suitable friction modifiers long
chain fatty acid derivatives of amines, long chain fatty esters, or
derivatives of a long chain fatty epoxides; fatty imidazolines; and
amine salts of alkylphosphoric acids. As used herein, the term
"fatty" means a carbon chain having 10 to 22 carbon atoms,
typically a straight carbon chain.
[0093] Friction modifiers may be present at 0.01 to 5 wt. % (e.g.,
0.1 to 1.5 wt. %) of the lubricating oil composition.
[0094] Corrosion Inhibitors
[0095] Corrosion inhibitors protect lubricated metal surfaces
against chemical attack by water or other contaminants. Suitable
corrosion inhibitors include polyoxyalkylene polyols and esters
thereof, polyoxyalkylene phenols, thiadiazoles and anionic alkyl
sulfonic acids. Such additives may be present at 0.01 to 5 wt. %
(e.g., 0.1 to 1.5 wt. %) of the lubricating oil composition.
[0096] Foam Inhibitors
[0097] Foam control can be provided by many compounds including a
foam inhibitor of the polysiloxane type (e.g., silicone oil or
polydimethyl siloxane). Foam inhibitors may be present at less than
0.1 wt. % (e.g., 0.0001 to 0.01 wt. %) of the lubricating oil
composition.
[0098] Pour Point Depressants
[0099] Pour point depressants lower the minimum temperature at
which a fluid will flow or can be poured. Suitable pour point
depressants include C.sub.8 to C.sub.18 dialkyl fumarate/vinyl
acetate copolymers, polyalkylmethacrylates and the like. Such
additives may be present at 0.01 to 5 wt. % (e.g., 0.1 to 1.5 wt.
%) of the lubricating oil composition.
EXAMPLES
[0100] The following illustrative examples are intended to be
non-limiting.
Example 1
[0101] A lubricating oil composition was prepared that contained a
major amount of a base oil of lubricating viscosity and the
following additives, to provide a finished oil having a HTHS
viscosity at 150.degree. C. of 1.5 cP: [0102] (1) 2.4 wt. % of an
ethylene carbonate post-treated bis-succinimide; [0103] (2) 1 wt. %
of a borated bis-succinimide dispersant; [0104] (3) 0.14 wt. % in
terms of calcium content, of a mixture of a 17 TBN calcium
sulfonate detergent, a 168 TBN calcium salicylate detergent, and a
323 TBN calcium salicylate detergent; [0105] (4) 510 ppm in terms
of magnesium content, of a 400 TBN magnesium sulfonate detergent;
[0106] (5) 740 ppm in terms of phosphorus content, of a mixture of
a primary zinc dialkyldithiophosphate and a secondary zinc
dialkyldithiophosphate; [0107] (6) 1.4 wt. % of an alkylated
diphenylamine; [0108] (7) 5 ppm in terms of silicon content, of a
foam inhibitor; [0109] (8) 3.0 wt. % of a polyalkylmethacrylate
viscosity modifier having a PSSI of 1; and [0110] (9) the
remainder, a Group II base oil (YUBASE.RTM. 2).
Example 2
[0111] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that a molybdenum-succinimide
complex was added to provide 300 ppm by weight of molybdenum to the
lubricating oil composition.
[0112] The succinimide of the molybdenum-succinimide complex was
prepared from polyisobutenyl (1000 MW) succinic anhydride and a
mixture of polyethylene polyamine oligomers.
Example 3
[0113] A lubricating oil was prepared in accordance with the
formulation of Example 2 except that the molybdenum-succinimide
complex was added was added to provide 1000 ppm by weight of
molybdenum to the lubricating oil composition.
Example 4
[0114] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that a molybdenum dithiocarbamate
(SAKURA-LUBE.RTM. 151; ADEKA Corporation) was added to provide 300
ppm by weight of molybdenum to the lubricating oil composition.
Example 5
[0115] A lubricating oil was prepared in accordance with the
formulation of Example 4 except that the molybdenum dithiocarbamate
was added to provide 1000 ppm by weight of molybdenum to the
lubricating oil composition.
Example 6
[0116] A lubricating oil was prepared in accordance with the
formulation of Example 1 except that a molybdenum ester/amide
(MOLYVAN.RTM. 855; Vanderbilt Chemicals) was added to provide 300
ppm by weight of molybdenum to the lubricating oil composition.
Example 7
[0117] A lubricating oil was prepared in accordance with the
formulation of Example 6 except that the molybdenum ester/amide was
added to provide 1000 ppm by weight of molybdenum to the
lubricating oil composition.
Example 8
[0118] A lubricating oil composition was prepared that contained a
major amount of a base oil of lubricating viscosity and the
following additives, to provide an SAE 0W-8 finished oil: [0119]
(1) 2.4 wt. % of an ethylene carbonate post-treated
bis-succinimide; [0120] (2) 1 wt. % of a borated bis-succinimide
dispersant; [0121] (3) 0.14 wt. % in terms of calcium content, of a
mixture of a 17 TBN calcium sulfonate detergent, a 168 TBN calcium
salicylate detergent, and a 323 TBN calcium salicylate detergent;
[0122] (4) 510 ppm in terms of magnesium content, of a 400 TBN
magnesium sulfonate detergent; [0123] (5) 740 ppm in terms of
phosphorus content, of a mixture of a primary zinc
dialkyldithiophosphate and a secondary zinc dialkyldithiophosphate;
[0124] (6) 1.4 wt. % of an alkylated diphenylamine; [0125] (7) 5
ppm in terms of silicon content, of a foam inhibitor; [0126] (8)
3.5 wt. % of a polyalkylmethacrylate viscosity modifier having a
PSSI of 1; and [0127] (9) the remainder, a Group II base oil
(YUBASE.RTM. 3).
Example 9
[0128] A lubricating oil was prepared in accordance with the
formulation of Example 8 except that a molybdenum-succinimide
complex was added to provide 300 ppm by weight of molybdenum to the
lubricating oil composition.
[0129] The succinimide of the molybdenum-succinimide complex was
prepared from polyisobutenyl (1000 MW) succinic anhydride and a
mixture of polyethylene polyamine oligomers.
Example 10
[0130] A lubricating oil was prepared in accordance with the
formulation of Example 9 except that a molybdenum-succinimide
complex was added to provide 1000 ppm by weight of molybdenum to
the lubricating oil composition.
Example 11
[0131] A lubricating oil was prepared in accordance with the
formulation of Example 8 except that a molybdenum dithiocarbamate
(SAKURA-LUBE.RTM. 151; ADEKA Corporation) was added to provide 300
ppm by weight of molybdenum to the lubricating oil composition.
Example 12
[0132] A lubricating oil was prepared in accordance with the
formulation of Example 11 except that the molybdenum
dithiocarbamate was added to provide 1000 ppm by weight of
molybdenum to the lubricating oil composition.
Example 13
[0133] A lubricating oil was prepared in accordance with the
formulation of Example 8 except that a molybdenum ester/amide
(MOLYVAN.RTM. 855; Vanderbilt Chemicals) was added to provide 300
ppm by weight of molybdenum to the lubricating oil composition.
Example 14
[0134] A lubricating oil was prepared in accordance with the
formulation of Example 13 except that the molybdenum ester/amide
was added to provide 1000 ppm by weight of molybdenum to the
lubricating oil composition.
Example 15
[0135] A lubricating oil composition was prepared that contained a
major amount of a base oil of lubricating viscosity and the
following additives, to provide an SAE 0W-12 finished oil: [0136]
(1) 2.4 wt. % of an ethylene carbonate post-treated
bis-succinimide; [0137] (2) 1 wt. % of a borated bis-succinimide
dispersant; [0138] (3) 0.14 wt. % in terms of calcium content, of a
mixture of a 17 TBN calcium sulfonate detergent, a 168 TBN calcium
salicylate detergent, and a 323 TBN calcium salicylate detergent;
[0139] (4) 510 ppm in terms of magnesium content, of a 400 TBN
magnesium sulfonate detergent; [0140] (5) 740 ppm in terms of
phosphorus content, of a mixture of a primary zinc
dialkyldithiophosphate and a secondary zinc dialkyldithiophosphate;
[0141] (6) 1.4 wt. % of an alkylated diphenylamine; [0142] (7) 5
ppm in terms of silicon content, of a foam inhibitor; [0143] (8)
2.0 wt. % of a polyalkylmethacrylate viscosity modifier having a
PSSI of 1; and [0144] (9) the remainder, a Group III base oil
(YUBASE.RTM. 4).
Example 16
[0145] A lubricating oil was prepared in accordance with the
formulation of Example 15 except that a molybdenum-succinimide
complex was added to provide 300 ppm by weight of molybdenum to the
lubricating oil composition.
[0146] The succinimide of the molybdenum-succinimide complex was
prepared from polyisobutenyl (1000 MW) succinic anhydride and a
mixture of polyethylene polyamine oligomers.
Example 17
[0147] A lubricating oil was prepared in accordance with the
formulation of Example 16 except that the molybdenum-succinimide
complex was added to provide 1000 ppm by weight of molybdenum to
the lubricating oil composition.
Example 18
[0148] A lubricating oil was prepared in accordance with the
formulation of Example 15 except that a molybdenum dithiocarbamate
(SAKURA-LUBE.RTM. 151; ADEKA Corporation) was added to provide 300
ppm by weight of molybdenum to the lubricating oil composition.
Example 19
[0149] A lubricating oil was prepared in accordance with the
formulation of Example 18 except that the molybdenum
dithiocarbamate was added to provide 1000 ppm by weight of
molybdenum to the lubricating oil composition.
Example 20
[0150] A lubricating oil was prepared in accordance with the
formulation of Example 15 except that a molybdenum ester/amide
(MOLYVAN.RTM. 855; Vanderbilt Chemicals) was added. The composition
contained 300 ppm molybdenum based on the total weight of the
lubricating oil composition.
Example 21
[0151] A lubricating oil was prepared in accordance with the
formulation of Example 20 except that the molybdenum ester/amide
was added to provide 1000 ppm by weight of molybdenum to the
lubricating oil composition.
Testing
[0152] The lubricating oil compositions were evaluated in the
Komatsu Hot Tube Test, the SRV Friction Test and the Shell Four
Ball Wear Test to assess their performance.
[0153] Detergency and thermal and oxidative stability are
performance areas that are generally accepted in the industry as
being essential to satisfactory overall performance of a
lubricating oil. The Komatsu Hot Tube test is a lubrication
industry bench test (JPI 5S-55-99) that measures the detergency and
thermal and oxidative stability of a lubricating oil. During the
test, a specified amount of test oil is pumped upwards through a
glass tube that is placed inside an oven set at a certain
temperature. Air is introduced in the oil stream before the oil
enters the glass tube, and flows upward with the oil. Evaluations
of the lubricating oils were conducted at a temperature of
280.degree. C. The test result is determined by comparing the
amount of lacquer deposited on the glass test tube to a rating
scale ranging from 1.0 (very black) to 10.0 (perfectly clean).
[0154] The friction reducing performance of each lubricating oil
composition was evaluated by means of a cylinder-on-desk
reciprocating sliding tester (SRV manufactured by Optimol) under
conditions of 400 N of load, 0.4 GPa of surface pressure (maximum
Hertz stress), 10 Hz of frequency, 1.50 mm of amplitude,
100.degree. C. of temperature, 60 minutes of testing time. The
friction characteristic was evaluated by calculating the average
friction coefficient which is an averaged friction coefficient for
the time of 30 to 60 minutes after beginning of the test. This
measurement conditions correspond to the conditions of boundary
lubrication.
[0155] The wear preventative performance of each lubricating oil
composition was determined in accordance with ASTM D4172 under
conditions of 1200 rpm, oil temperature of 80.degree. C. and load
of 30 kgf for periods of 30 minutes. After testing, the test balls
were removed, the wear scars were measured and the diameter shown
as the result.
[0156] The properties and performance results of the lubricating
oil compositions having a HTHS viscosity at 150.degree. C. of 1.5
cP (Examples 1-7) are summarized in Table 2 below.
[0157] The properties and performance results of the SAE 0W-8
viscosity grade lubricating oil compositions (Examples 8-14) are
summarized in Table 3 below.
[0158] The properties and performance results of the SAE 0W-12
viscosity grade lubricating oil compositions (Examples 15-21) are
summarized in Table 4 below.
[0159] As shown in Tables 2-4, lubricating oil compositions
containing a Mo-succinimide complex (Examples 2-3, 9-10, and 16-17)
provide comparable or superior friction reducing properties to
lubricating oil compositions containing conventional
organomolybdenum friction modifiers at very low viscosity grades
while maintaining wear and detergency performance. Lubricating oils
containing the molybdenum ester/amide exhibited the poorest
friction reducing properties.
TABLE-US-00002 TABLE 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7
Mo, Mo ester/amide -- -- -- -- -- 300 1000 ppm MoDTC -- -- -- 300
1000 -- -- Mo-succinimide -- 300 1000 -- -- -- -- Kinematic
Viscosity (100.degree. C.), mm.sup.2/s 3.9 4.0 4.2 3.9 4.0 3.9 4.0
Viscosity Index 208 209 210 207 206 206 207 CCS Viscosity
(-35.degree. C.), cP 1002 1035 1125 985 1024 1026 1076 HTHS
Viscosity (150.degree. C.), cP 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Noack
Volatility, % 60 60 60 60 60 60 60 P, wt. % 0.074 0.074 0.074 0.074
0.074 0.074 0.074 S, wt. % 0.18 0.18 0.19 0.21 0.29 0.18 0.18 Zn,
wt. % 0.088 0.088 0.088 0.088 0.088 0.088 0.088 Ca, wt. % 0.14 0.14
0.14 0.14 0.14 0.14 0.14 Mg, wt. % 0.051 0.051 0.051 0.051 0.051
0.051 0.051 B, wt. % 0.006 0.006 0.006 0.006 0.006 0.006 0.006 Mo,
wt. % -- 0.030 0.10 0.030 0.10 0.030 0.10 N, wt. % 0.09 0.11 0.14
0.10 0.11 0.10 0.13 Ca/Mg mass ratio 2.8 2.8 2.8 2.8 2.8 2.8 2.8
Komatsu Hot Tube Test Merit Rating.sup.(a) 8.5 8.0 6.0 8.5 6.5 8.5
6.5 SRV Friction Test Coefficient of Friction 0.17 0.073 0.043
0.067 0.050 0.086 0.068 Shell 4 Ball Wear Test Wear Scar Diameter,
mm 0.39 0.39 0.38 0.44 0.39 0.45 0.39 .sup.(a)Merit rating > 7
(Good); Merit Rating = 6-7 (Marginally Acceptable); and Merit
Rating < 6 (Poor)
TABLE-US-00003 TABLE 3 Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Ex.
14 SAE Viscosity Grade 0W-8 0W-8 0W-8 0W-8 0W-8 0W-8 0W-8 Mo, Mo
ester/amide -- -- -- -- -- 300 1000 ppm MoDTC -- -- -- 300 1000 --
-- Mo-succinimide -- 300 1000 -- -- -- -- Kinematic Viscosity
(100.degree. C.), mm.sup.2/s 4.8 4.9 5.2 4.8 4.9 4.8 4.9 Viscosity
Index 205 207 209 205 206 206 206 CCS Viscosity (-35.degree. C.),
cP 1898 1954 2106 1907 1923 1957 2012 HTHS Viscosity (150.degree.
C.), cP 1.8 1.8 1.9 1.8 1.8 1.7 1.8 Noack Volatility, % 37 37 37 37
37 37 37 P, wt. % 0.074 0.074 0.074 0.074 0.074 0.074 0.074 S, wt.
% 0.18 0.18 0.19 0.21 0.29 0.18 0.18 Zn, wt. % 0.088 0.088 0.088
0.088 0.088 0.088 0.088 Ca, wt. % 0.14 0.14 0.14 0.14 0.14 0.14
0.14 Mg, wt. % 0.051 0.051 0.051 0.051 0.051 0.051 0.051 B, wt. %
0.006 0.006 0.006 0.006 0.006 0.006 0.006 Mo, wt. % -- 0.030 0.10
0.030 0.10 0.030 0.10 N, wt. % 0.09 0.11 0.14 0.10 0.11 0.10 0.13
Ca/Mg mass ratio 2.8 2.8 2.8 2.8 2.8 2.8 2.8 Komatsu Hot Tube Test
Merit Rating.sup.(a) 8.5 8.5 7.0 8.5 7.0 8.5 6.5 SRV Friction Test
Coefficient of Friction 0.17 0.071 0.042 0.058 0.053 0.11 0.069
Shell 4 Ball Wear Test Wear Scar Diameter, mm 0.39 0.44 0.42 0.38
0.41 0.40 0.39 .sup.(a)Merit rating > 7 (Good); Merit Rating =
6-7 (Marginally Acceptable); and Merit Rating < 6 (Poor)
TABLE-US-00004 TABLE 4 Ex. 15 Ex. 16 Ex. 17 Ex. 18 Ex. 19 Ex. 20
Ex. 21 SAE Viscosity Grade 0W-12 0W-12 0W-12 0W-12 0W-12 0W-12
0W-12 Mo, Mo ester/amide -- -- -- -- -- 300 1000 ppm MoDTC -- -- --
300 1000 -- -- Mo-succinimide -- 300 1000 -- -- -- -- Kinematic
Viscosity (100.degree. C.), mm.sup.2/s 5.6 5.7 6.0 5.6 5.7 5.6 5.7
Viscosity Index 166 167 168 166 166 164 168 CCS Viscosity
(-35.degree. C.), cP 4478 4621 4960 4506 4549 4561 4737 HTHS
Viscosity (150.degree. C.), cP 2.1 2.1 2.1 2.1 2.1 2.0 2.0 Noack
Volatility, % <15 <15 <15 <15 <15 <15 <15 P,
wt. % 0.074 0.074 0.074 0.074 0.074 0.074 0.074 S, wt. % 0.18 0.18
0.19 0.21 0.29 0.18 0.18 Zn, wt. % 0.088 0.088 0.088 0.088 0.088
0.088 0.088 Ca, wt. % 0.14 0.14 0.14 0.14 0.14 0.14 0.14 Mg, wt. %
0.051 0.051 0.051 0.051 0.051 0.051 0.051 B, wt. % 0.006 0.006
0.006 0.006 0.006 0.006 0.006 Mo, wt. % -- 0.030 0.10 0.030 0.10
0.030 0.10 N, wt. % 0.09 0.11 0.14 0.10 0.11 0.10 0.13 Ca/Mg mass
ratio 2.8 2.8 2.8 2.8 2.8 2.8 2.8 Komatsu Hot Tube Test Merit
Rating.sup.(a) 8.5 8.5 6.5 8.5 7.0 8.5 6.0 SRV Friction Test
Coefficient of Friction 0.17 0.062 0.048 0.057 0.052 0.079 0.059
Shell 4 Ball Wear Test Wear Scar Diameter, mm 0.41 0.39 0.39 0.42
0.39 0.44 0.30 .sup.(a)Merit rating > 7 (Good); Merit Rating =
6-7 (Marginally Acceptable); and Merit Rating < 6 (Poor)
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