U.S. patent application number 11/731880 was filed with the patent office on 2008-07-17 for low sap engine lubricant additive and composition containing non-corrosive sulfur and organic borates.
Invention is credited to William H. Buck, Douglas E. Deckman, L. Oscar Farng, Andrew G. Horodysky, Steven Kennedy.
Application Number | 20080171677 11/731880 |
Document ID | / |
Family ID | 38610149 |
Filed Date | 2008-07-17 |
United States Patent
Application |
20080171677 |
Kind Code |
A1 |
Buck; William H. ; et
al. |
July 17, 2008 |
Low SAP engine lubricant additive and composition containing
non-corrosive sulfur and organic borates
Abstract
The present invention is directed to a lubricating oil
composition comprising a lubricating oil basestock, a
boron-containing additive of at least 0.1 weight percent of the
composition and less than 8.0 weight percent, and ashless sulfur
additive of at least 0.1 weight percent of the composition and less
than 4.0 weight percent, a dispersant-detergent-inhibitor system of
less than 15 percent weight percent of the composition, a zinc
dithiophosphate additive of at least 0.2 weight percent of the
composition and less than 2.0 weight percent of the composition.
The elements in the formulated oil composition having at least 100
and less than 630 PPM phosphorus, at least 1,000 PPM and less than
3,000 PPM, at least 100 and less than 630 ppm Phosphorous, and at
least 105 PPM and less than 710 PPM zinc. In a second embodiment,
an additive composition for lubricating oils is disclosed. In a
third embodiment, a method to obtain favorable lubricating
properties is disclosed.
Inventors: |
Buck; William H.; (West
Chester, PA) ; Farng; L. Oscar; (Lawrenceville,
NJ) ; Deckman; Douglas E.; (Mullica Hill, NJ)
; Kennedy; Steven; (West Chester, PA) ; Horodysky;
Andrew G.; (Cherry Hill, NJ) |
Correspondence
Address: |
ExxonMobil Research and Engineering Company
P.O. Box 900
Annandale
NJ
08801-0900
US
|
Family ID: |
38610149 |
Appl. No.: |
11/731880 |
Filed: |
March 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60791775 |
Apr 13, 2006 |
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|
Current U.S.
Class: |
508/151 |
Current CPC
Class: |
C10M 2203/1025 20130101;
C10N 2030/10 20130101; C10M 2203/1006 20130101; C10M 2205/173
20130101; C10M 2219/024 20130101; C10N 2060/14 20130101; C10M
2219/06 20130101; C10M 2219/104 20130101; C10M 2219/106 20130101;
C10N 2030/45 20200501; C10M 141/12 20130101; C10M 2223/045
20130101; C10M 2215/064 20130101; C10M 2227/061 20130101; C10M
2227/062 20130101; C10N 2030/04 20130101; C10N 2030/42 20200501;
C10M 2215/086 20130101; C10M 2207/289 20130101; C10M 2219/083
20130101; C10M 2217/043 20130101; C10N 2010/04 20130101; C10M
2207/026 20130101; C10N 2040/25 20130101; C10M 2219/066 20130101;
C10M 2219/08 20130101; C10N 2030/43 20200501; C10N 2030/44
20200501; C10N 2030/06 20130101; C10N 2030/12 20130101; C10M
2205/0285 20130101; C10N 2010/12 20130101; C10M 2215/28
20130101 |
Class at
Publication: |
508/151 |
International
Class: |
C10M 169/04 20060101
C10M169/04 |
Claims
1. A composition, comprising: a. a lubricating oil basestock; b. an
organic boron containing additive present in an amount of at least
0.01 and less than 8.0 weight percent of the composition; c. a
dispersant-detergent-inhibitor system of less than 15 weight
percent of the composition; d. a non-corrosive ashless sulfur
additive present in an amount of at least 0.1 and less than 4.0
weight percent of the composition; e. a zinc dithiophosphate
additive present in an amount of at least 0.2 weight percent of the
composition and less than 2.0 weight percent of the composition;
and f. the composition having at least 100 PPM and less than 630
PPM phosphorus, at least 105 PPM and less than 710 PPM zinc, at
least 1,000 PPM and less than 3,000 PPM sulfur, at least 80 PPM and
less than 450 PPM Boron.
2. The composition of claim 1 further comprising at least one
performance additive wherein the additives are chosen form the
group comprising zinc dithiophosphates, borated or non-borated
dispersants, phenolic and aminic ashless anti-oxidants, metal
detergents, molybdenum or organic friction modifiers, defoamants,
seal swell additives, pour point depressants and others including
contemporary dispersant-detergent-inhibitor (DDI) additive
packages, and any combination thereof.
3. The composition of claim 1 wherein the base stock is chosen from
the group consisting of group II base stocks, group III base
stocks, group IV base stocks, and group V base stocks,
gas-to-liquids base stocks, and any combination thereof.
4. The composition of claim 1 wherein the dispersant systems
comprises additives chosen from the group consisting of borated and
non-borated succinimides, succinic acid-esters and amides,
alkylphenol-polyamine coupled Mannich adducts, and any combination
thereof.
5. The composition of claim 1 further comprising an ashless
antioxidant additive.
6. The composition of claim 1 further comprising a metallic
detergent or detergent system.
7. The composition of claim 6 wherein the detergent system provides
a total base number (TBN) less than 9, preferably less than 7 and
most preferably less than 5, to the formulated lubricant
composition.
8. The composition of claim 1 further comprising a viscosity
modifier additive.
9. The composition of claim 1 wherein the organic borate is a
borated hydroxyl esters chosen from the group consisting of borated
glycerol mono-oleate, borated glycerol di-oleate, borated glycerol
tri-oleate, borated glycerol mono-cocoate, borated mono-talloate,
borated glycerol mono-sorbitate, borated polyol esters and any
combination thereof
10. The composition of claim 1 wherein the non corrosive sulfur
additive is chosen from the group consisting of ashless derivatives
of thiadiazoles, ashless derivatives of benzothiazoles, ashless
alkyl, aryl sulfides/di-sulfides/tri-sulfide including thianthrene,
diphenyl disulfide, dinonyl disulfide, dipyridyl disulfide, and
their alkylates, ashless dithiocarbamates, thioesters/sulfurized
esters, thioglycolates, dialkyl thiodipropionates, dialkyl
dithiopropionates, and any combination thereof.
11. The composition of claim 10 wherein the non-corrosive, organic
sulfur additive is a sulfur/nitrogen containing, heterocyclic or
non-heterocyclic antiwear-antioxidant additive.
12. The composition of claim 11 wherein the non-corrosive, organic
sulfur additive is an ashless dithiocarbamate additive.
13. The composition of claim 11 wherein the non-corrosive, organic
sulfur additive is thiadiazole-derived antiwear additive.
14. A lubricant additive system for a lubricant composition,
comprising: a. an organic boron containing additive of at least 0.4
weight percent and less than 32 weight percent of the additive; b.
a detergent-dispersant system of less than 60 percent weight
percent of the additive; c. a zinc dithiophosphate additive of at
least 0.8 weight percent of the composition and less than 8.0
weight percent of the additive; and d. a non-corrosive ashless
sulfur additive of at least 0.4 and less than 16.0 weight percent
of the additive.
15. The lubricant additive of claim 14 wherein the total lubricant
additive treat is in the range of at least 0.1 weight percent to 25
weight percent of the lubricant composition.
16. The lubricant additive of claim 14 further comprising a
molybdenum additive.
17. The lubricant additive of claim 16 wherein the molybdenum
additive is an organic molybdenum additive.
18. The lubricant additive of claim 14 wherein the zinc
dithiophosphate additive comprises a primary alkyl alcohol derived,
or a secondary alkyl alcohol derived zinc dithiophosphate or a
combination thereof.
19. A method comprising a. obtaining a composition comprising a
lubricating oil basestock, an organic boron containing additive
present in the amount of at least 0.1 and less than 8 weight
percent of the composition, a dispersant-detergent-inhibitor system
of less than 15 percent weight percent of the composition, a zinc
dithiophosphate additive present in the amount of at least 0.2
weight percent of the composition and less than 2.0, weight percent
of the composition, a non corrosive ashless sulfur additive present
in the amount of at least 0.1 and less than 4.0 weight percent of
the composition wherein the composition has at least 100 PPM and
less than 630 PPM phosphorus, at least 105 PPM and less than 710
PPM zinc, at least 1,000 PPM and less than 30,000 PPM sulfur, at
least 80 PPM and less than 450 PPM Boron; and b. lubricating an
engine with the composition to achieve favorable anti-wear,
oxidation and cleanliness.
20. A method for reducing sulfur in exhaust gasses in an internal
combustion engine, comprising: a. obtaining a composition
comprising a lubricating oil basestock, an organic boron containing
additive present in the amount of at least 0.1 and less than 8
weight percent of the composition, a dispersant-detergent-inhibitor
system of less than 15 percent weight percent of the composition,
zinc dithiophosphate additive present in the amount of at least 0.2
weight percent of the composition and less than 2.0, weight percent
of the composition, a non corrosive ashless sulfur additive present
in the amount of at least 0.1 and less than 4.0 weight percent of
the composition wherein the composition has at least 100 PPM and
less than 630 PPM phosphorus, at least 105 PPM and less than 710
PPM zinc, at least 1,000 PPM and less than 30,000 PPM sulfur, at
least 80 PPM and less than 450 PPM Boron; b. lubricating the
internal combustion engine with the composition.
Description
This application claims benefit of Provisional Application
60/791,775 filed Apr. 13, 2006.
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to lubricating oil compositions
suitable for use in internal combustion engines. More particularly,
this invention relates to a low ash, sulfur, and phosphorous
lubricating oil composition.
[0003] 2. Background
[0004] Many means have been employed to reduce overall wear and
friction as well as to control oxidation/cleanliness in modern
engines, particularly automobile engines. The primary methods
include prolonging engine life by reducing engine wear and
increasing the resistance to oxidation by reducing the engine's
sludge/deposit build-up through oil degradation. Some of the
solutions to reducing wear have been strictly mechanical including
building engines with wear resistant alloy or ceramic parts,
modifying the contact geometry and adding special coating
materials. Solutions to improve cleanliness also involve
modification of oil, including the use of metal containing
detergents. Recently, considerable work has also been done with
lubricating oils to enhance their anti-wear/anti-oxidation
properties by modifying them with ashless antioxidants and
anti-wear components.
[0005] Contemporary lubricants such as engine oils use mixtures of
additive components to include numerous performances benefits.
Examples of additives components include, anti-wear and extreme
pressure components, fuel economy improving components, friction
reducers, dispersants, detergents, corrosion inhibitors and
viscosity index improving additive. These additives provide energy
conservation, engine cleanliness and durability and high
performance levels to the lubricating oil under a wide range of
engine operability conditions including temperature, pressure and
lubricant service life.
[0006] Throughout the world, legislation aimed at reducing
automotive emissions is forcing down the level of sulfur in fuels.
Recently, lubricants are coming under scrutiny as a source of air
pollution and emission catalyst deactivation. Phosphorus is known
to be poisonous to automotive three-way HC conversion
catalysts.
[0007] Conventional engine oil technology relies heavily on zinc
(dialkyl) dithiophosphate ("ZnDTP" or "ZDDP"). ZnDTP is a
versatile, anti-wear/anti-oxidant component that provides extremely
low cam and lifter wear and favorable oxidation protection under
severe conditions. ZnDTPs are disadvantageous, especially at high
treat rates because they carry the three disfavorable elements of
Zn, S, P and no reduction in phosphorus and zinc levels can be
realized until new additive technology permits replacing or
eliminating zinc dithiophosphates. Sulfur is known to be poisonous
to deNox catalysts and zinc phosphates cause plugging of the
exhaust particulate filters. The sulfur, ash and phosphorous
components in oil are commonly referred to as "SAP" or "SAPS" in
the art.
[0008] The major problem with ZnDTP is the poisoning effects to
after-treatment devices that may aggravate emission problems. In
addition, ZnDTP has strong interactions with dispersants,
detergents, other anti-wear components and MoDTC causing
antagonistic effects on friction, sludge and deposit, if
inappropriate concentrations are utilized. Replacing ZnDTP
additives is not a simple endeavor because the wear protection
demand for today's engine is extremely high and place extremely
rigorous chemical limits on any reductions in ZnDTP treat
levels.
[0009] Engine lubricating oils are often used in high temperature
applications, where extreme temperatures can significantly reduce
the useful life of the lubricant. Under high temperatures, the
lubricant can become oxidized prematurely unless a strong
antioxidant system can also be employed in the oil to prevent this
degradation process. Good piston, ring, cam and lifter wear
protection are also an important characteristic of today's engine
oil. Additionally, many engine oils are often required to perform
well in the presence of water, therefore, protecting against rust
formation. Traditionally, ZnDTPs are used to provide adequate
protection as described above. Engine designers are now requiring
even greater anti-wear protection and more demanding test protocols
are being put in place to insure that lubricants can meet these
more stringent specifications. However, stringent regulations in
emission control have forced lubricant formulators to move away
from ZnDTPs for the reasons discussed above.
[0010] Accordingly, there is a need for an additive or additive
system for engine oils that has the ability to improve both rust
and wear protection, and at the same time significantly enhance
oxidative stability, while meeting stringent emission requirements.
This invention satisfies that need.
SUMMARY OF THE INVENTION
[0011] In a first embodiment, a lubricating oil composition is
disclosed. This composition comprises a lubricating oil basestock,
a boron-containing additive present in the amount in the range of
at least 0.1 weight percent of the composition and less than 8.0
weight percent, a non-corrosive sulfur additive present in the
amount in the range of at least 0.1 weight percent of the
composition and less than 4.0 weight percent, a
dispersant-detergent-inhibitor system of less than 15 percent
weight percent of the composition, a zinc dithiophosphate additive
present in the amount in the range of at least 0.2 weight percent
of the composition and no more than 2.0 weight percent of the
composition wherein weight percent is active ingredient weight of
the composition. The formulated oil composition having at least 100
and less than 630 PPM phosphorus, at least 1,000 PPM and less than
3,000 PPM sulfur, and at least 105 PPM and less than 710 PPM zinc,
at least 80 PPM and less than 450 PPM boron.
[0012] In a second embodiment, an additive composition for
lubricating oils is disclosed. This composition comprises an
organic boron containing additive present in the amount in the
range of at least 0.4 weight percent and less than 32 weight
percent of the additive, a detergent-dispersant system of less than
60 percent weight percent of the additive, a zinc dithiophosphate
additive present in the amount in the range of at least 0.8 weight
percent and less than 8.0 weight percent of the additive, a
non-corrosive ashless sulfur additive present in the amount in the
range of at 0.4 and less than 16.0 weight percent of the
additive.
[0013] In a third embodiment, a method of obtain a favorable
lubricating properties is disclosed. This method, comprises
obtaining a composition comprising a lubricating oil basestock, an
organic boron containing additive of at least 0.1 and less than 8
weight percent of the composition, a dispersant-detergent-inhibitor
system of less than 15 percent weight percent of the composition,
zinc dithiophosphate additive of at least 0.2 weight percent of the
composition and no more than 2.0 weight percent of the composition,
a non corrosive ashless sulfur additive of at 0.1 and less than 4.0
weight percent of the composition. The formulated oil composition
having at least 100 and less than 630 PPM phosphorus, at least
1,000 PPM and less than 3,000 PPM sulfur, and at least 105 PPM and
less than 710 PPM zinc, at least 80 PPM and less than 450 PPM
boron.
DETAILED DESCRIPTION OF THE INVENTION
[0014] This invention relates to engine lubricants formulated with
unique functional fluids and/or additives to achieve performance
improvements. One embodiment is a low SAP engine lubricant
composition comprising combinations of organic borates,
non-corrosive sulfur compounds, optional high levels of ashless
antioxidants, and low levels of ZnDTP to achieve high level of
performance equal to or better than using high level of ZnDTP
alone. In one embodiment, component synergy is built upon a variety
of functionalities to achieve well balanced performance features.
In a preferred embodiment, these performance features favorably
exceed engine oils formulated with high levels of zinc
dithiophosphates and metallic detergents.
[0015] In a second embodiment, the lubricating oils maintain low
frictional properties of film under various operating conditions.
This embodiment favorably maintains sufficiently high film
thickness at high operating temperatures to provide a minimum
lubricant film to protect against wear at a variety of
temperatures.
[0016] In a third embodiment, the lubricating oil maintains
cleanliness over the entire range of operating conditions while
reducing wear to a minimum. In a fourth embodiment, the lubricating
oil provides favorable oxidation and corrosion control, under the
most severe operating conditions.
[0017] It has been discovered that non-corrosive, organic sulfur
compounds when blended with high levels of organic borates, and low
level of zinc dithiophosphates provide substantial property
benefits. In a preferred embodiment, high levels of ashless
antioxidants are added to the compounds to achieve even more
favorable-property benefits. These benefits include but are not
limited to reductions in wear, corrosion, and increases in oil
induction temperature or time (OIT) during oxidative conditions
that result in potentially significant improvements in engine oil
service life and durability with excellent overall performance
benefits. In an additional embodiment, these benefits can be
achieved without deleterious effects such as instability,
undesirable high viscosity, deposits and the like, when the
additives are added to lubricating oils. This new engine oil
technology is based on an advanced anti-wear, anti-friction and
antioxidant system, in combination of some typical, contemporary
dispersants, ashless antioxidants, detergents, defoamants and other
additives including contemporary DI additive packages. These
additives enhance anti-wear, anti-oxidation and anti-corrosion
performance.
[0018] Persons skilled in the art with the benefit of the
disclosure herein will recognize the ability to include additives
that favorably enhances lubricant performance including
anti-friction, anti-oxidation and anti-wear performance while
successfully meeting the stringent wear, oxidation and cleanliness
performance requirements in modern engines. Examples of suitable
additives include but are not limited to contemporary zinc
dithiophosphates in low levels, borated or non-borated dispersants,
phenolic and aminic ashless anti-oxidants, high and low levels of
metal detergents, molybdenum or organic friction modifiers,
defoamants, seal swell additives, pour point depressants including
contemporary DDI additive packages, and any combination
thereof.
[0019] The preferred organic borates are borated hydroxyl esters,
such as borated glycerol mono-oleate (GMO), borated glycerol
di-oleate (GDO), borated glycerol tri-oleate (GTO), borated
glycerol mono-cocoate (GMC), borated mono-talloate (GMT), borated
glycerol mono-sorbitate (GMS), borated polyol esters with pendant
hydroxyl groups, such as borated pentaerythritol di-C8 ester, and
any combination thereof. Short chain tri-hydroxyl orthoborates may
be used but are not desirable due to their relatively poor
thermal/oxidative stability properties when compared to borated
hydroxyl esters. Borated dispersants and borated detergents can be
used as a source of boron. However, in order to achieve best
overall performance, specific organic borates, such as borated
hydroxyl esters are more preferable.
[0020] The preferred non-corrosive sulfur compounds are chosen from
the group consisting of ashless derivatives of thiadiazoles,
ashless derivatives of benzothiazoles, ashless alkyl or aryl
sulfides and poly sulfides, for example, di-sulfides and
tri-sulfide including thianthrene and its alkylates, diphenyl
sulfide and disulfide, and their alkylates, dinonyl sulfide or
disulfide, dipyridyl sulfide or disulfide, and their alkylates,
ashless dithiocarbamates, and thioesters/sulfurized esters
including thioglycolates, dialkyl thiodipropionates, dialkyl
dithiopropionates. Examples of ashless thiadiazoles are Vanlube
871.TM., Cuvan 826.TM. and Cuvan 484.TM.. Examples of ashless
dithiocarbamates are Vanlube 7723.TM. and Vanlube 981. A
prerequisite to the selection of sulfur additives is that they all
need to meet copper corrosion requirements according to ASTM (D130)
and low temperature storage compatibility tests.
[0021] The anti-corrosion performance can be judged by the copper
corrosion test ASTDM D130 under normal conditions. For ASTDM test
D130-6 normal conditions are at 250 degrees Fahrenheit at 3 hours.
For ASTDM test D130-8, normal conditions are set at 210 degrees
Fahrenheit for 6 hours with percent water, as well as a more severe
condition at 250 degrees Fahrenheit for 24 hours. For purposes of
this invention, non-corrosive sulfur shall be defined as any sulfur
that provides a performance classification of 2B or better under
the ASTM D-130 Copper Corrosion Test.
[0022] Dibenzyl disulfide was deficient in a severe copper
corrosion test at degrees Fahrenheit for 24 hours and
2,2'-dipyridyl disulfide has poor low temperature compatibility in
engine oils. Therefore, both additives are deemed less favorable,
despite of their strong EP performance. Sulfur additives containing
a small portion of polysulfides (tri-sulfide/tetra-sulfide and
higher order of polysulfides) are still acceptable providing that
they could meet the copper corrosion requirements.
[0023] The preferred ashless antioxidants are hindered phenols and
arylamines. Typical examples are
butylated/octylated/styrenated/nonylated/dodecylated
diphenylamines, 4,4'-methylene bis-(2,6-di-tert-butylphenol),
2,6-di-tert-butyl-p-cresol, octylated phenyl-alpha-naphthylamine,
alkyl ester of 3,5-di-tert-butyl-4-hydroxy-phenyl propionic acid,
and many others. Sulfur-containing antioxidants, such as sulfur
linked hindered phenols and thiol esters can also be used.
[0024] Suitable dispersants include borated and non-borated
succinimides, succinic acid-esters and amides,
alkylphenol-polyamine coupled Mannich adducts, other related
components and any combination thereof. In some embodiments, it can
often be advantageous to use mixtures of such above described
dispersants and other related dispersants. Examples include
additives that are borated, those that are primarily of higher
molecular weight, those that consist of primarily mono-succinimide,
bis-succinimide, or mixtures of above, those made with different
amines, those that are end-capped, dispersants wherein the
back-bone is derived from polymerization of branched olefins such
as polyisobutylene or from polymers such as other polyolefins other
than polyisobutylene, such as ethylene, propylene, butene, similar
dispersants and any combination thereof. The averaged molecular
weight of the hydrocarbon backbone of most dispersants, including
polyisobutylene, is in the range from 1000 to 6000, preferably from
1500 to 3000 and most preferably around 2200.
[0025] Suitable detergents include but are not limited to calcium
phenates, calcium sulfonates, calcium salicylates, magnesium
phenates, magnesium sulfonates, magnesium salicylates, metal
carbonates, related components including borated detergents, and
any combination thereof. The detergents can be neutral, mildly
overbased, or highly overbased. The amount of detergents usually
contributes a total base number (TBN) in a range from 1 to 9 for
the formulated lubricant composition. Metal detergents have been
chosen from alkali or alkaline earth calcium or magnesium phenates,
sulfonates, salicylates, carbonates and similar components.
[0026] Antioxidants have been chosen from hindered phenols,
arylamines, dihydroquinolines, phosphates,
thiol/thiolester/disulfide/trisulfide, low sulfur peroxide
decomposers and other related components. These additives are rich
in sulfur, phosphorus and/or ash content as they form strong
chemical films to the metal surfaces and thus need to be used in
limited amount in reduced sulfur, ash and phosphorous lubricating
oils.
[0027] Inhibitors and antirust additives may be used as needed.
Seal swell control components and defoamants may be used with the
mixtures of this invention. Various friction modifiers may also be
utilized. Examples include but are not limited to amines, alcohols,
esters, diols, triols, polyols, fatty amides, various molybdenum
phosphorodithioates (MoDTP), molybdenum dithiocarbamates (MoDTC),
sulfur/phosphorus free organic molybdenum components, molybdenum
trinuclear components, and any combination thereof.
[0028] In a preferred embodiment, this new synergistic combination
has significantly improved these critical performance parameters
while maintaining excellent compatibility to exhaust
after-treatment devices. This embodiment comprises a novel
anti-wear, friction reduction and antioxidant system consisting of
organic borates, non-corrosive sulfur additives, high level of
ashless antioxidants and low levels of zinc dithiophosphates. More
specifically, this formulated engine oil embodiment comprises about
100 to 630 ppm phosphorus, and about 0.1 to 0.3 wt % sulfur and
from about 80 to 450 ppm boron, and about 0.5 to 3.0 wt % ashless
antioxidants such as total amounts of hindered phenols and
arylamines.
[0029] These components can be used with a variety of base stocks,
including group I, II, III, IV, and V, and gas-to-liquids ("GTL")
as well as a variety of mixtures thereof. However, due to other
performance requirements including volatility, stability,
viscometrics, and cleanliness feature, premium engine oils prefer
to use group II and higher ("Group II+") base oils to ensure that
they can achieve desirable overall performance levels as well as
maximizing the full potential of the unique synergies among
additives. Additional significant synergies were identified among
alkylated aromatics and Group II+high performance base stocks
including Group II, III, IV, V, VI or GTL base stocks.
[0030] Groups I, II, III, IV and V are broad categories of base oil
stocks developed and defined by the American Petroleum Institute
(API Publication 1509; www.API.org) to create guidelines for
lubricant base oils. Group I base stocks generally have a viscosity
index of between about 80 to 120 and contain greater than about
0.03% sulfur and/or less than about 90% saturates. Group II base
stocks generally have a viscosity index of between about 80 to 120,
and contain less than or equal to about 0.03% sulfur and greater
than or equal to about 90% saturates. Group III stock generally has
a viscosity index greater than about 120 and contains less than or
equal to about 0.03% sulfur and greater than about 90% saturates.
Group IV includes polyalphaolefins (PAO). Group V base stocks
include base stocks not included in Groups I-IV. Table 1 summarizes
properties of each of these five groups.
TABLE-US-00001 TABLE 1 Base Stock Properties Saturates Sulfur
Viscosity Index Group I <90% and/or >0.03% and .gtoreq.80 and
< 120 Group II .gtoreq.90% and .ltoreq.0.03% and .gtoreq.80 and
< 120 Group III .gtoreq.90% and .ltoreq.0.03% and .gtoreq.120
Group IV Polyalphaolefins (PAO) Group V All other base oil stocks
not included in Groups I, II, III, or IV
[0031] Base stocks having a high paraffinic/naphthenic and
saturation nature of greater than 90 weight percent can often be
used advantageously in certain embodiments. Such base stocks
include Group II and/or Group III hydroprocessed or hydrocracked
base stocks, or their synthetic counterparts such as
polyalphaolefin oils, GTL or similar base oils or mixtures of
similar base oils.
[0032] In a preferred embodiment, at least about 20 percent of the
total composition should consist of such Group II or Group III base
stocks or GTL, with at least about 30 percent being preferable, and
more than about 80 percent on being most preferable. Gas to liquid
base stocks can also be preferentially used with the components of
this invention as a portion or all of the base stocks used to
formulate the finished lubricant. We have discovered, favorable
improvement when the components of this invention are added to
lubricating systems comprising primarily Group II, Group III and/or
GTL base stocks compared to lesser quantities of alternate
fluids.
[0033] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds, and/or elements as
feedstocks such as hydrogen, carbon dioxide, carbon monoxide,
water, methane, ethane, ethylene, acetylene, propane, propylene,
propyne, butane, butylenes, and butynes. GTL base stocks and base
oils are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons, for example waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feedstocks. GTL base stock(s) include oils boiling in
the lube oil boiling range separated/fractionated from GTL
materials such as by, for example, distillation or thermal
diffusion, and subsequently subjected to well-known catalytic or
solvent dewaxing processes to produce lube oils of reduced/low pour
point; wax isomerates, comprising, for example, hydroisomerized or
isodewaxed synthesized hydrocarbons; hydroisomerized or isodewaxed
Fischer-Tropsch ("F-T") material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates); preferably
hydroisomerized or isodewaxed F-T hydrocarbons or hydroisomerized
or isodewaxed F-T waxes, hydroisomerized or isodewaxed synthesized
waxes, or mixtures thereof.
[0034] GTL base stock(s) derived from GTL materials, especially,
hydroisomerized/isodewaxed F-T material derived base stock(s), and
other hydroisomerized/isodewaxed wax derived base stock(s) are
characterized typically as having kinematic viscosities at
100.degree. C. of from about 2 mm.sup.2/s to about 50 mm.sup.2/s,
preferably from about 3 mm.sup.2/s to about 50 mm.sup.2/s, more
preferably from about 3.5 mm.sup.2/s to about 30 mm.sup.2/s, as
exemplified by a GTL base stock derived by the isodewaxing of F-T
wax, which has a kinematic viscosity of about 4 mm.sup.2/s at
100.degree. C. and a viscosity index of about 130 or greater. The
term GTL base oil/base stock and/or wax isomerate base oil/base
stock as used herein and in the claims is to be understood as
embracing individual fractions of GTL base stock/base oil or wax
isomerate base stock/base oil as recovered in the production
process, mixtures of two or more GTL base stocks/base oil fractions
and/or wax isomerate base stocks/base oil fractions, as well as
mixtures of one or two or more low viscosity GTL base stock(s)/base
oil fraction(s) and/or wax isomerate base stock(s)/base oil
fraction(s) with one, two or more high viscosity GTL base
stock(s)/base oil fraction(s) and/or wax isomerate base
stock(s)/base oil fraction(s) to produce a dumbbell blend wherein
the blend exhibits a viscosity within the aforesaid recited range.
Reference herein to Kinematic viscosity refers to a measurement
made by ASTM method D445.
[0035] GTL base stocks and base oils derived from GTL materials,
especially hydroisomerized/isodewaxed F-T material derived base
stock(s), and other hydroisomerized/isodewaxed wax-derived base
stock(s), such as wax hydroisomerates/isodewaxates, which can be
used as base stock components of this invention are further
characterized typically as having pour points of about -5.degree.
C. or lower, preferably about -10.degree. C. or lower, more
preferably about -15.degree. C. or lower, still more preferably
about -20.degree. C. or lower, and under some conditions may have
advantageous pour points of about -25.degree. C. or lower, with
useful pour points of about -30.degree. C. to about -40.degree. C.
or lower. If necessary, a separate dewaxing step may be practiced
to achieve the desired pour point. References herein to pour point
refer to measurement made by ASTM D97 and similar automated
versions.
[0036] The GTL base stock(s) derived from GTL materials, especially
hydroisomerized/isodewaxed F-T material derived base stock(s), and
other hydroisomerized/isodewaxed wax-derived base stock(s) which
are base stock components which can be used in this invention are
also characterized typically as having viscosity indices of 80 or
greater, preferably 100 or greater, and more preferably 120 or
greater. Additionally, in certain particular instances, viscosity
index of these base stocks may be preferably 130 or greater, more
preferably 135 or greater, and even more preferably 140 or greater.
For example, GTL base stock(s) that derive from GTL materials
preferably F-T materials especially F-T wax generally have a
viscosity index of 130 or greater. References herein to viscosity
index refer to ASTM method D2270.
[0037] In addition, the GTL base stock(s) are typically highly
paraffinic of greater than 90 percent saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stocks and base oils typically have very low sulfur and nitrogen
content, generally containing less than about 10 ppm, and more
typically less than about 5 ppm of each of these elements. The
sulfur and nitrogen content of GTL base stock and base oil obtained
by the hydroisomerization/isodewaxing of F-T material, especially
F-T wax is essentially nil.
[0038] In a preferred embodiment, the GTL base stock(s) comprises
paraffinic materials that consist predominantly of non-cyclic
isoparaffins and only minor amounts of cycloparaffins. These GTL
base stock(s) typically comprise paraffinic materials that consist
of greater than 60 wt % non-cyclic isoparaffins, preferably greater
than 80 wt % non-cyclic isoparaffins, more preferably greater than
85 wt % non-cyclic isoparaffins, and most preferably greater than
90 wt % non-cyclic isoparaffins.
[0039] Useful compositions of GTL base stock(s), hydroisomerized or
isodewaxed F-T material derived base stock(s), and wax-derived
hydroisomerized/isodewaxed base stock(s), such as wax
isomerates/isodewaxates, are recited in U.S. Pat. Nos. 6,080,301;
6,090,989, and 6,165,949 for example.
[0040] The principle advantage of one embodiment of this invention
is the unique synergistic combination of organic borates,
non-corrosive sulfur additives in the presence of low level zinc
dithiophosphates and high level of ashless antioxidants that
provides favorable oxidation, corrosion stability, and more
importantly, anti-wear performance. These favorable performance
levels can be achieved while reducing the levels of sulfur,
phosphorus and zinc in the engine oil formulations compared to the
typical engine oil used today.
[0041] In one embodiment, the general formulation of the low SAP
engine oil is summarized in Table 2. In this table and throughout
the application weight percent is intended to be active ingredient
weight percent of the entire composition unless otherwise
stated.
TABLE-US-00002 TABLE 2 Elements in Formulated Oils Component Type
Wt % (ppm) + Other Restrictions Organic-containing 0.1-8.0% 80 to
450 PPM boron boron additive Zinc dithiophosphate 0.2-2.0% 100 to
530 PPM phosophorous and additive 105 to 710 PPM zinc
Dispersant-detergent- <15.0% inhibitor system Non-corrosive
ashless 0.1-4.0% 1,000 to 3,000 PPM sulfur sulfur additive Ashless
antioxidants 0.5-3.0%
EXAMPLES
[0042] Table 3 illustrates low temperature stabilities for
different ashless antiwear additives for low phosphorous lubricant
oils with a phosphorous level of 0.05 weight percent of the
composition. Table 3 illustrates various embodiments for two
reference base oils formulations. Both base Reference oils A and B
are formulated with the premium Group III base oils.
TABLE-US-00003 TABLE 3 Entry 7 1 2 3 4 5 6 Comparative oil
Reference Comparative Comparative Comparative Comparative Reference
5 oil A oil 1 oil 2 oil 3 oil 4 oil B RN 4717 Ashless AW 0.2% Ald-4
0.3% Ald-4 0.2% Ald-2 0.3% Ald-2 .25% Dibenzyl additive
S.sub.2-pyridine S.sub.2-pyridine S.sub.2-pyridine S.sub.2-pyridine
Disulfide 0.05% P 0.05% P 0.05% P 0.05% P 0.05% P (0.05% P) (0.05%
P) Solubility C & B Dropout Dropout C & B C & B C &
B C & B Appearance at 5C At 5C Cu 3 1A 1A Corrosion
hrs/250.degree. F. (D130-6) Cu 3 2C 1B 1B 2B 2C 1B 1B Corrosion
hrs/210.degree. F./ (D130-8) H2O Cu 24 1A 2A 2A 3A 4A 1A 4A
Corrosion hrs/250.degree. F. (D130-9) PDSC Onset T 246.7 239.6 245
242.7 238.8 229.7 228.5 (Ramp (.degree. C.) 10.degree. C./min)
288.degree. C., 16 hrs Tube Rating 3 6 6.9 4.5 5.5 3.8 3.3 (1 =
Clean) 4 Ball Wear WSD 0.6 0.6 (D4172) (mm) 40 Kg/1800 K Factor 7
6.2 rpm/30 min./ 200.degree. F. Aldrithiol-4 4,4'- Disulfide
[2645-22-9] dipyridyl 4 Ball EP LNS (Kg) Aldrithiol-2 2,2'-
Disulfide [2127-03-9] 80 80 (D2783) dipyridyl 30.degree. C./10 Weld
Ld 200 200 sec./1760 rpm (Kg) LWI 34.5 35.2 HFRR Ave. 0.147 0.107
Friction 0.7 Kg/60 % Ave. 12.3 10.7 Hz/0.5 mm/ film 60
min./75.degree. Scar X/Y 0.3/0.77 0.30/0.73 C. (mm) Calc. Sc. 0.181
0.173 Area
[0043] Now referring to Table 3, comparative oils 1, 2, 3 and 4 are
variations of reference oil A. The formulation for reference oil A
is disclosed in Table 4.
TABLE-US-00004 TABLE 4 Low ash Descriptions engine oil Blend Code
4866XNP005-D Batch Number 1 Additive Sytem 1 Antioxidants 2
Additive System 2 Detergents/ 9.25 dispersants Additive System 3
Viscosity modifiers 14 Additive System 4 Other performance 0.3
additives Base oil System Group III Balance BASELINE D 130 8
Corrosion of Cu by 2C Petroleum D 130 9 250 F./24 Corrosion of Cu
by 1A hrs Petroleum D445 5 KV at 100 Kinematic Viscosity 9.868 C.,
CST @100 C. D5293 6 AppVis App. Viscosity 4400 CCS -30, CP @ Low
Temp D6443 MAGNESIUM, Add Metals in Lubes 0.0469 WT % D6443 SULFUR,
Add Metals in Lubes 0.1825 WT % D6443 PHOSPHORUS, Add Metals in
Lubes 0.0476 WT % D6443 CALCIUM, Add Metals in Lubes 0.0329 WT %
D6443 CHLORINE, Add Metals in Lubes 0.0095 WT % D6443 COPPER, Add
Metals in Lubes <0.0020000001 WT % D6443 ZINC, Add Metals in
Lubes 0.0554 WT %
[0044] Again referring to table 3, comparative oil 5 is a
variations of reference oil B. The formulation for reference oil B
is disclosed in Table 5.
TABLE-US-00005 TABLE 5 Blend Code OSCARLOWSPA-C Batch Number ZnDTP
tree base blend 1 Base oil System Group III Base Oi) Balance
Additive System 1 Antioxidants 1.5 Additive System 2
Dispersants/Detergents 9.5 Additive System 3 Viscosity Modifiers 7
Additive System 4 All other performance additives 0..05 Group III
Base Oil with a minimum VI of 120, a typical pour point of - 15C
and a typical sul- REFERENCE fur <10 ppm D 445 5 KV at 100 C.,
CST Kinematic Viscosity at 100 C. 12.1 D 874 Sulfated Ash, WT %
Sulfated Ash from Lubes, Addtv 0.32 D2896 TBN of Petroleum Products
4.12 D4683, CP HTHS Tapered Bearing Visc Test 3.53 D4684 6 Yield
Stress, PA Yield Stress, App. Viscosity >350 D4684 6 Appar
Viscos 1, CP Yield Stress, App. Viscosity >500000 D4684 6 Appar
Viscos 2, CP Yield Stress, App. Viscosity >500000 D4684 6 Appar
Viscos 3, CP Yield Stress, App. Viscosity >500000 D5293 6 AppVis
CCS -30, CP App. Viscosity @ Low Temp 5080 D6443 MAGNESIUM, WT %
Add Metals in Lubes 0.0494 D6443 SULFUR, WT % Add Metals in Lubes
0.072 D6443 PHOSPHORUS, WT % Add Metals in Lubes <0.0020000001
D6443 CALCIUM, WT % Add Metals in Lubes 0.0334 D6443 CHLORINE, WT %
Add Metals in Lubes 0.0047 D6443 COPPER, WT % Add Metals in Lubes
<0.0020000001 D6443 ZINC, WT % Add Metals in Lubes
<0.0020000001 D5185 Boron, PPM 170 D5185 Molybdenum, PPM
<0.5
[0045] Table 3 also illustrates copper corrosion test from the ASTM
D-130 method. Table 6 illustrates the various classifications from
the ASTDM Copper Corrosion test. As shown in table 6,
Classifications 1A, 1B, 2A, and 2B are the non-corrosive preferred
classifications with classifications 2C, 2D, 2,E, 3A, 3B, 4A, 4B,
and 4C being the non preferred classifications.
TABLE-US-00006 TABLE 6 ASTM D-130 Copper Corrosion Tests Classifi-
Corrosion cation Designation Description Comment Freshly -- --
Non-corrosive, polished preferred strip 1A Slightly tarnish Light
orange, Non-corrosive, almost the same preferred as freshly pol.
Strip 1B Slightly tarnish Dark orange Non-corrosive, preferred 2A
Moderate tarnish Claret red Non-corrosive, preferred 2B Moderate
tarnish Lavender Non-corrosive, preferred 2C Moderate tarnish
Multicolored with Not preferred lavender blue or silver 2D Moderate
tarnish Silvery Not preferred 2E Moderate tarnish Brassy or gold
Not preferred 3A Dark tarnish Magenta overcast Not preferred on
brassy strip 3B Dark tarnish Multicolored with Not preferred red
and green, but no gray 4A Corrosion Transparent black, Not
preferred dark gray or brown with green 4B Corrosion Green barely
showing Not preferred 4C Corrosion Graphite or luster- Not
preferred less black glassy or jet black
[0046] As shown in columns 2 and 3 of table 3, very poor low
temperature stability, labeled as solubility appearance is observed
when 0.2 to 0.3% of Aldrithiol-4 was respectively added to the low
phosphorous reference A base oil formulation in column 1. This poor
oil compatibility issue correlates well with the poor hot tube
deposit test results. As shown in columns 4 and 5 adding 0.2 and
0.3% of Aldrithiol-2 improves the oil compatibility but the copper
corrosion becomes unacceptable in columns 4 and 5.
[0047] A similar evaluation was conducted when 0.25% dibenzyl
disulfide described in comparative oil 5 is added to reference oil
B base formulation as described in table 3. In this example, the
4-Ball wear and EP performance improves slightly, and the average
friction and calculated wear scar area in High Frequency
Reciprocating Rig (HFRR) reduces significantly comparing reference
oil B with comparative oil 5. However, the copper corrosion at
250.degree. F. for the 24 hour test conditions remains poor as
shown by a 4A rating for comparative oil 5.
[0048] Now referring to table 6, any ratings in classification
categories 2C-2E, 3 and 4 are not preferred as they can cause
darkening and discoloration of the copper coupons that strongly
indicate corrosive or near corrosive behavior. To achieve the
additive synergy embodiment described in this invention, a very
stringent preferred range is established for defining non-corrosive
sulfur additives. Accordingly, dibenzyl disulfide and Aldrithiol-2
are not preferred due to their corrosive sulfur species and thus
not recommended for low SAP engine oils.
[0049] Reference oil B is a ZnDTP free blend developed so different
amounts of ZnDTP as well as other non-corrosive organic sulfur
additives can be added to show comparative performance results. The
base formulation is formulated with Group III base oils with a
minimum of 120 viscosity index, a typical pour point of -15.degree.
C., a typical Noack of 15 and a typical sulfur of 10 ppm with a
miximum sulfur content less than 30 ppm. Similarly, the base engine
oil formulated is also formulated with GTL oils with a minimum of
135 viscosity index, a typical pour point of -17.degree. C. and a
typical sulfur of less than 1 ppm.
[0050] Table 7, illustrates that very good oxidation/corrosion
control can be achieved with combinations of non-corrosive sulfur
additives, borated dispersants, high level of ashless antioxidants
and low level of zinc dithiophosphates in a low Phosphorus engine
oil. Columns one and two represent reference oils C and D and
Columns 3, 4 and 5 represent respectively comparative oils 6, 7,
and 8 which are variation of reference oil D. Reference oil C is a
low SAP group III base oil with 0.1 weight percent phosphorous.
Whereas, reference oil D and example comparative oils 6, 7, and 8
are Group III low SAP base oils with 0.05 weight percent
phosphorous. Slight variations in the formulations are also
documented in Table 7.
TABLE-US-00007 TABLE 7 Entry 3 4 5 1 2 Comparative Comparative
Comparative Reference Reference oil 6 oil 7 oil 8 oil C oil D
Ashless DTC Sulfur ester DTC/Sulfur ZnDTP 1% 0.50% 0.50% 0.50%
0.50% Ashless AW additive .25% VL981 .5% RC-2411 .25% VL981 Ashless
AW additive .25% RC-2515 Borated Dispersant and 9.5% 9.5% 9.5% 9.5%
9.5% Ashless Antioxidant Low ash/S/P Gp III Estimate by (0.10% P)
(0.05% P) (0.05% P) (0.05% P) (0.05% P) theory Solubility Clear and
Clear and Clear and Clear and Clear and Appearance bright bright
bright bright bright 4 Ball Wear (D4172) WSD (mm) 0.59 0.62 0.57
0.57 0.53 40 Kg/1800 rpm/.5 hr/200 F. K Factor 5.7 7.0 5.0 4.8 3.7
4 Ball EP (D2783) LNS (Kg) 80 80 80 100 100 30.degree. C./10
sec./1760 rpm Weld Ld (Kg) 200 200 200 200 200 LWI 35.1 34.5 41.5
41.5 41.8 Cu Corrosion (D130-6) 3 hrs/250 F. 1A 1A 1A 1A 1A Cu
Corrosion (D130-8) 3 hrs/210 F./H2O 1A 1B 1B 1B 1A Cu Corrosion
(D130-9) 24 hrs/250 F. 1A 1A 1B 1B 1B PDSC (Ramp 10.degree. C./min)
Onset T (.degree. C.) 232 229.7 233.6 237.6 237.7 Hot Tube Test 3.5
3.8 3 2.8 3.3 (288 C./16 hr) HFRR Ave. Friction 0.139 0.147 0.118
0.105 0.121 0.7 Kg/60 Hz/0.5 mm/ Calc. Sc. Area 0.174 0.181 0.173
0.173 0.154 60 min./75.degree. C. TBN D2896 4.27 4.23 4.14 4.04
4.23 Sulfated Ash (wt %) D874 0.53 0.38 0.38 0.32 0.38 Boron (wt %)
D5185 0.017 0.017 0.017 0.017 0.017 Phosphorus (wt %) D6443 0.1003
0.0507 0.0488 0.0482 0.0494 Zinc (wt %) D6443 0.1118 0.0577 0.0573
0.0564 0.0569 Calcium (wt %) D6443 0.0329 0.0332 0.0331 0.0328
0.0327 Magnesium (wt %) D6443 0.0595 0.0496 0.0507 0.0505 0.0479
Copper (wt %) D6443 <0.002 <0.002 <0.002 <0.002
<0.002 Chlorine (wt %) D6443 0.0047 0.0049 0.0052 0.0053 0.0049
Sulfur (wt %) D6443 0.2799 0.1783 0.2109 0.2198 0.2526 Pin-on-V
Block Pass Pass Pass 500 Lb, 210 minutes Ave Scar (mm) 0.432 0.418
0.387
[0051] The non-corrosive sulfur additives in comparative example
embodiment oil 6 is an ashless dithiocarbamates ("DTC") called
Vanlube.TM.981. Vanlube.TM.981 is an experimental additive
available from R.T. Vanderbilt Chemical Company. Comparative oils 7
and 8 are specific sulfurized ester/olefins with low sulfur content
with or without DTC as in comparative oils 7 and 8 and are
respectively labeled RC-2411 and RC-2515. RC-2411 and RC-2515 are
commercially available from Rhein Chemie Chemical Company] The good
corrosion control is evidenced by 1A to 2B copper corrosion ratings
under various conditions. The anti-oxidation performance of oils 6,
7, and 8 are slightly better than reference oil D. These properties
are evidenced by Pressurized Differential Scanning Calorimetry
("PDSC") by about 4 to 8 degrees higher onset temperature. In the
ramping method of PDSC of 10 degrees Celsius per minute, the higher
the onset temperature, the better the resistance to oxidation.
Generally, oxidation rates generally double with about 10 degrees
Celsius increase in temperature. Therefore, these results can be
translated into about 40 percent to 80 percent better in terms of
control of viscosity or acid number increases or any other
comparable measurements for control of oxidation.
[0052] When non-corrosive sulfur additives were added as in
comparative embodiment oils 6, 7 and 8, the 4-Ball wear and 4-Ball
EP results are all consistently better than the Reference oil D. A
slight reduction in wear scar diameter of between 8 to 14 percent
can be observed for the ASTDM D4172 4-Ball wear conditions which
translate into a 29 to 47 percent calculated reduction in wear
volume shown as the K-factor. The last non-seizure load ("LNS") and
load-wear index ("LWI") are 21 to 25 percent better for oils 6, 7,
and 8 when compared to the performance of reference 4 in the 4-Ball
EP tests.
[0053] The HFRR data showed that those non-corrosive sulfur
additives can help maintain excellent frictional properties as well
as wear reduction as evidenced by the lower average coefficients of
friction of between 18 to 29 and approximately 4 to 15 percent
smaller calculated scar area. Overall, example comparison oils 6,
7, and 8 formulated with 0.05% phosphorus plus non-corrosive sulfur
additives provide favorable performance when compared to a typical
engine oil, with full load of ZDDP as in the 1 weight percent
reference oil C. This demonstrates the strong synergistic effect
exists of the various embodiments of example oils 6, 7, and 8. All
the additive components of examples 6, 7, and 8 are fully
compatible with engine oils as evidenced by their clear and bright
appearance in storage over a period of several months. Table 7
demonstrates satisfactory stability for oils containing
non-corrosive sulfur additives. Lastly, the pin-on-. V block shown
as Falex wear test results correlate well with 4-Ball wear/EP
results indicating better wear control with comparative oils 6 and
7 versus Reference oil D.
[0054] In Table 8, another low SAP oil was also evaluated.
Comparative oil 9 is a low SAP Group III base with a final
composition of 0.025 weight percent phosphorous.
TABLE-US-00008 TABLE 8 Entry 4 1 2 3 Comparative oil 9 Base
Reference E Reference F DTC/S ester ZnDTP Secondary ZDDP 0% 0.25%
0.50% 0.25% Ashless AW additive .25% VL981 .25% RC-2411 Borated
Dispersant and 9.5% 9.5% 9.5% 9.5% Ashless Antioxidant Low ash/S/P
Gp III (0% P) (0.025% P) (0.05% P) (0.025% P) Solubility C & B
C & B C & B C & B Appearance 4 Ball EP (D2783) LNS (Kg)
50 63 80 80 30 C./10 sec./1760 rpm Weld Ld (Kg) 160 200 200 200 LWI
22.0 28.21 34.5 34.4 Cu Corrosion (D130-6) 3 hrs/250.degree. F. 1B
1B 1A 1B Cu Corrosion (D130-8) 3 hrs/210.degree. F./H2O 3A 1A 1B 1B
HFRR Ave. Friction 0.144 0.127 0.147 0.126 0.7 Kg/60 Hz/0.5 mm/
Calc. Sc. Area 0.211 0.173 0.181 0.173 60 min./75.degree. C. TBN
D2896 4.12 5.45 4.23 4.52 Sulfated Ash (wt %) D874 0.32 0.33 0.38
0.33 Boron (wt %) D5185 0.017 0.017 0.017 0.017 Phosphorus (wt %)
D6443 <0.002 0.0244 0.0507 0.0258 Zinc (wt %) D6443 <0.002
0.0287 0.0577 0.03 Calcium (wt %) D6443 0.4859 0.0331 0.0332 0.0323
Magnesium (wt %) D6443 0.0034 0.0501 0.0496 0.0508 Copper (wt %)
D6443 <0.002 <0.002 <0.002 <0.002 Chlorine (wt %) D6443
0.0055 0.0048 0.0049 0.0049 Sulfur (wt %) D6443 0.072 0.124 0.1783
0.1849
[0055] Equivalent average friction coefficients and calculated wear
scar area were observed in HFRR tests, but much improved last
non-seizure (LNS) load and load-wear index (LWI) were found in
4-Ball EP test when comparative oil 9 is compared to Reference oil
E. Actually, the 4-Ball EP performance of comparative oil D is
almost equivalent to that of Reference F where twice the amount of
ZDDP is used as shown by a final phosphorus weight percent of 0.05.
Although Reference oil E has strong 4-Ball EP performance, the HFRR
data are not as good as comparative oil 9 and Reference oil E. This
data clearly indicates that too much ZDDP can be antagonistic to
the frictional property. The base formulation, shown as base in
column of 1 of table 8 was also used to blend oils in Tables 6 and
7 and is fully described in Table 5 for reference.
[0056] Table 9 illustrates the evaluation of non-corrosive sulfur
additives in low SAP commercial vehicle lubricants ("CVL"). Table 9
is formulated with a low SAP base oil with no phosphorous.
TABLE-US-00009 TABLE 9 Entry 2 3 4 1 Comparative Comparative
Comparative oil Reference oil 10 oil 11 12 Commercial Engine Oil
Oil G Ashless DTC Borated GMO DTC + B-GMO ZnDTP Secondary 0.30%
0.30% 0.30% 0.30% ZDDP Ashless Antiwear 0.3% VL 981 0.3% VL 981
Ashless Friction Modifier 0.5% B-GMO 0.5% B-GMO Borated Dispersants
and 9.71% 9.71% 9.71% 9.71% Antioxidants Low ash/S/P (0.03% P)
(0.03% P) (0.03% P) (0.03% P) Solubility C&B C&B C&B
C&B Appearance 4 Ball Wear WSD (mm) 0.61 0.52 0.48 0.47 40
Kg/1200 rpm/60 min./200.degree. K Factor 4.86 2.36 1.71 1.44 F. 4
Ball Wear WSD (mm) 0.41 0.40 0.33 0.40 40 Kg/600 rpm/30
min./200.degree. F. K Factor 2.67 2.46 0.57 2.46 4 Ball EP (D2783)
LNS (Kg) 80 100 80 80 30 C./10 sec./1760 rpm Weld Ld (Kg) 200 200
200 200 LWI 33.6 41.2 34.0 34.2 Cu Corrosion (D130-6) 3
hrs/250.degree. F. 1A 1A 1A 1B Cu Corrosion (D130-8) 3
hrs/210.degree. F./H.sub.2O 1A 1A 1A 1A Cu Corrosion (D130-9) 24
hrs/250.degree. F. 1B 1B 1B 1B TBN D2896 7.88 8.04 8 7.98 Sulfated
Ash (wt %) D874 0.76 0.79 0.77 0.77 Phosphorus (wt %) D6443 0.0286
0.0287 0.0291 0.0285 Zinc (wt %) 0.0324 0.0326 0.0332 0.0325
Calcium (wt %) 0.1983 0.1986 0.1983 0.1967 Magnesium (wt %) 0.0038
0.0025 0.0024 0.0024 Copper (wt %) <0.002 <0.002 <0.002
<0.002 Chlorine (wt %) 0.008 0.008 0.0076 0.0077 Sulfur (wt %)
0.2237 0.2663 0.2233 0.2645
[0057] The composition of the base formulation of Table 9 is listed
in Table 10. As shown in Table 10 and column 3 of Table 9, this
base oil has no phosphorous. The base oil system consists of about
50% Group III and roughly about 20% Group I base oils. All oils
containing ZDDP and other sulfur/boron additives in Table 9 and 11
are formulated from the base formulation. Similarly, another base
formulation is formulated with GTL base oils. The base oil system
consists of more than 50% GTL and less than 20% Group I base
oils.
TABLE-US-00010 TABLE 10 Commercial Descriptions engine oil Blend
Code LSAP01-A Batch Number ZnDTP free base blend 1 Base oil system
Mixed Group I & III base oils Balanced Additive system 1
Antioxidants 0.5 Additive system 2 Detergent/dispersants 17.8
Additive system 3 Viscosity modifiers 9 Additive system 4 Other
performance additives 1.2
[0058] Now referring to table 9, in example oil 10, a 0.3 weight
percent of a non-corrosive sulfur additive, in this example an
ashless dithiocarbamate, is included in the engine oil formulated
with 0.03 weight percent phosphorus as shown by reference oil G.
The 4-Ball wear performance resulted in 2 to 15 percent improvement
in wear reduction or wear scar diameter ("WSD") and 8 to 51 percent
improvement in calculated wear volume or K-factor. Comparative oils
11 and 12 illustrate the synergists effect of combining borated GMO
with borated dispersants.
[0059] Similarly, Table 11 illustrates the 4-Ball EP and Hot Tube
performance of the combination of 0.3 percent ZDDP and 0.3 percent
of a non-corrosive sulfur additive for comparative oil 13 versus
the 0.6 percent ZDDP reference oil H. The total AW/EP additive
treat rate is the same 0.6 percent and the EP performance is about
the same, but the Hot Tube of Entry 4 is much better indicating a
cleaner environment. The 4-Ball EP performance of comparative oil
13 is stronger than reference oil I with reduced ZDDP at 0.3% and
the base oil in column 3 with 0% ZDDP.
TABLE-US-00011 TABLE 11 Entry 4 1 2 Comparative Reference Reference
3 oil 13 Commercial Engine Oil oil H oil I Base Ashless DTC ZnDTP
0.60% 0.30% 0% 0.30% Ashless Antiwear 0.3% VL 981 Ashless Friction
Modifier Borated Dispersants 9.71% 9.71% 9.71% 9.71% Antioxidants
Low ash/S/P (0.06% P) (0.03% P) 0% P (0.03% P) Solubility C&B
C&B C&B C&B Appearance 4 Ball EP (D2783) LNS (Kg) 100
80 63 100 30 C./10 sec./1760 rpm Weld Ld (Kg) 200 200 160 200 LWI
41.5 33.6 26.5 41.2 Cu Corrosion (D130-6) 3 hrs/250 F. 1A 1A 1B 1A
Cu Corrosion (D130-8) 3 hrs/210 F./H.sub.2O 1A 1A 1B 1A Cu
Corrosion (D130-9) 24 hrs/250 F. 1A 1B 2A 1B Hot Tube Test 4.0 1.5
(305 C./16 hr)
[0060] In summary, a new low SAP engine oil system has been
discovered based on very unique combinations of non-corrosive
sulfur additives, low level of ZDDP, borated components, with
preferably high level of ashless anti-oxidants. This formulation
exhibits outstanding and unexpected performance to modern engines.
One embodiment of this discovery provides an effective way to
reduce the amount of ZDDP for contemporary engine oils while
maintaining excellent wear, oxidation and corrosion protection.
This unique component synergism concept is believed to be
applicable to similar formulations containing low sulfur base oils
of less than 300 ppm, borated additives with borated hydroxyesters
such as borated GMO, and alternate organic borates such as borated
dispersants, non-corrosive sulfur additives, and preferably with
ashless antioxidants.
* * * * *
References