U.S. patent application number 16/010661 was filed with the patent office on 2018-10-18 for lubricating oil compositions with engine wear protection.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Douglas E. DECKMAN, Michael R. DOUGLASS, Beatrice M. GOODING, Andrew R. KONICEK, Alan M. SCHILOWITZ.
Application Number | 20180298302 16/010661 |
Document ID | / |
Family ID | 63791576 |
Filed Date | 2018-10-18 |
United States Patent
Application |
20180298302 |
Kind Code |
A1 |
GOODING; Beatrice M. ; et
al. |
October 18, 2018 |
LUBRICATING OIL COMPOSITIONS WITH ENGINE WEAR PROTECTION
Abstract
A method for improving wear control, while maintaining or
improving fuel efficiency, in an engine or other mechanical
component lubricated with a lubricating oil by using as the
lubricating oil a formulated oil. The formulated oil has a
composition including a lubricating oil base stock as a major
component, and a mixture as a minor component of (i) at least one
metal salt of a straight chain carboxylic acid, wherein the metal
is selected from the group consisting of palladium (Pd), silver
(Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at
least one metal salicylate salt, wherein the metal is calcium (Ca),
magnesium (Mg) or combinations thereof, wherein the molar ratio of
the total metal concentration from the salicylate salt divided by
the total metal concentration from the straight chain carboxylic
acid ranges from 0.1 to 40. The lubricating oils are useful in
internal combustion engines.
Inventors: |
GOODING; Beatrice M.;
(Hopewell, NJ) ; SCHILOWITZ; Alan M.; (Highland
Park, NJ) ; KONICEK; Andrew R.; (Whitehouse Station,
NJ) ; DECKMAN; Douglas E.; (Easton, PA) ;
DOUGLASS; Michael R.; (Cherry Hill, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
63791576 |
Appl. No.: |
16/010661 |
Filed: |
June 18, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14979719 |
Dec 28, 2015 |
10000721 |
|
|
16010661 |
|
|
|
|
62097661 |
Dec 30, 2014 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 129/40 20130101;
C10M 2223/045 20130101; C10M 137/10 20130101; C10M 2205/0206
20130101; C10N 2040/25 20130101; C10M 2207/141 20130101; C10M
129/46 20130101; C10M 169/04 20130101; C10M 2207/144 20130101; C10M
107/02 20130101; C10M 2219/044 20130101; C10N 2030/04 20130101;
C10N 2030/06 20130101; C10M 135/10 20130101; C10N 2030/54 20200501;
C10M 2207/16 20130101; C10M 129/54 20130101 |
International
Class: |
C10M 169/04 20060101
C10M169/04; C10M 107/02 20060101 C10M107/02; C10M 129/40 20060101
C10M129/40; C10M 129/46 20060101 C10M129/46; C10M 129/54 20060101
C10M129/54; C10M 135/10 20060101 C10M135/10; C10M 137/10 20060101
C10M137/10 |
Claims
1. A method for improving wear control, while maintaining or
improving fuel efficiency, in an engine or other mechanical
component lubricated with a lubricating oil by using as the
lubricating oil a formulated oil, said formulated oil having a
composition comprising a lubricating oil base stock as a major
component; and a mixture as a minor component of (i) at least one
metal salt of a straight chain carboxylic acid, wherein the metal
is selected from the group consisting of palladium (Pd), silver
(Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at
least one metal salicylate salt, wherein the metal is calcium (Ca),
magnesium (Mg) or combinations thereof, wherein the molar ratio of
the total metal concentration from the salicylate salt divided by
the total metal concentration from the straight chain carboxylic
acid ranges from 0.1 to 40; and wherein wear control is improved
and fuel efficiency is maintained or improved as compared to wear
control and fuel efficiency achieved using a lubricating oil
containing a minor component other than the mixture of the at least
one metal salt of a straight chain carboxylic acid and the at least
one metal salicylate salt.
2. The method of claim 1 wherein the lubricating oil base stock
comprises a Group I, Group II, Group III, Group IV or Group V base
oil.
3. The method of claim 1 wherein the straight chain carboxylic acid
is an aliphatic, saturated, unbranched carboxylic acid having from
8 to 26 carbon atoms, and mixtures thereof.
4. The method of claim 1 wherein the straight chain carboxylic acid
is palmitic acid (C16), stearic acid (C18), or combinations
thereof.
5. The method of claim 1 wherein the at least one metal salt of the
straight chain carboxylic acid comprises zinc stearate, silver
stearate, palladium stearate, zinc palmitate, silver palmitate,
palladium palmitate, or mixtures thereof.
6. The method of claim 1 wherein the at least one metal salt of the
straight chain carboxylic acid is present in an amount of from 0.01
weight percent to 5 weight percent, based on the total weight of
the formulated oil.
7. The method of claim 1 wherein the at least one metal salicylate
salt is present in an amount of from 0.01 weight percent to 5
weight percent, based on the total weight of the formulated
oil.
8. The method of claim 1 wherein the lubricating oil base stock is
present in an amount of from 70 weight percent to 95 weight
percent, based on the total weight of the formulated oil.
9. The method of claim 1 wherein the formulated oil further
comprises one or more of an antiwear additive, viscosity modifier,
antioxidant, detergent, other dispersant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, anti-foam agent, inhibitor, and anti-rust additive.
10. The method of claim 1, wherein the at least one metal salt of
the straight chain carboxylic acid comprises zinc stearate.
11. The method of claim 10, wherein the at least one metal
salicylate salt is calcium salicylate.
12. The method of claim 11, wherein the molar ratio of the total
metal concentration from the salicylate salt divided by the total
metal concentration from the straight chain carboxylic acid ranges
from 0.4 to 10.
13. A lubricating oil having a composition comprising a lubricating
oil base stock as a major component; and a mixture as a minor
component of (i) at least one metal salt of a straight chain
carboxylic acid, wherein the metal is selected from the group
consisting of palladium (Pd), silver (Ag), gold (Au), zinc (Zn),
and combinations thereof, and (ii) at least one metal salicylate
salt, wherein the metal is calcium (Ca), magnesium (Mg) or
combinations thereof; wherein the molar ratio of the total metal
concentration from the salicylate salt divided by the total metal
concentration from the straight chain carboxylic acid ranges from
0.1 to 40; and wherein wear control is improved and fuel efficiency
is maintained or improved as compared to wear control and fuel
efficiency achieved using a lubricating oil containing a minor
component other than the mixture of the at least one metal salt of
a straight chain carboxylic acid and the at least one metal
salicylate salt.
14. The lubricating oil of claim 13 wherein the lubricating oil
base stock comprises a Group I, Group II, Group III, Group IV or
Group V base oil.
15. The lubricating oil of claim 13 wherein the straight chain
carboxylic acid is an aliphatic, saturated, unbranched carboxylic
acid having from 8 to 26 carbon atoms, and mixtures thereof.
16. The lubricating oil of claim 13 wherein the straight chain
carboxylic acid is palmitic acid (C16), stearic acid (C18), or
combinations thereof.
17. The lubricating oil of claim 13 wherein the at least one metal
salt of the straight chain carboxylic acid comprises zinc stearate,
silver stearate, palladium stearate, zinc palmitate, silver
palmitate, palladium palmitate, and mixtures thereof.
18. The lubricating oil of claim 13 wherein the at least one metal
salt of the straight chain carboxylic acid is present in an amount
of from 0.01 weight percent to 5 weight percent, based on the total
weight of the formulated oil.
19. The lubricating oil of claim 13 wherein the at least one metal
salicylate salt is present in an amount of from 0.01 weight percent
to 5 weight percent, based on the total weight of the formulated
oil.
20. The lubricating oil of claim 13 wherein the lubricating oil
base stock is present in an amount of from 70 weight percent to 95
weight percent, based on the total weight of the formulated
oil.
21. The lubricating oil of claim 13 further comprising one or more
of an antiwear additive, other viscosity modifiers, antioxidant,
detergent, other dispersant, pour point depressant, corrosion
inhibitor, metal deactivator, seal compatibility additive,
anti-foam agent, inhibitor, and anti-rust additive.
22. The lubricating oil of claim 13, wherein the at least one metal
salt of the straight chain carboxylic acid comprises zinc
stearate.
23. The lubricating oil of claim 22, wherein the at least one metal
salicylate salt is calcium salicylate.
24. The lubricating oil of claim 23, wherein the molar ratio of the
total metal concentration from the salicylate salt divided by the
total metal concentration from the straight chain carboxylic acid
ranges from 0.4 to 10.
25. The lubricating oil of claim 13 which is a passenger vehicle
engine oil (PVEO).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation-in-Part application and
claims priority to pending U.S. application Ser. No. 14/979,719
filed on Dec. 28, 2015, the entirety of which is incorporated
herein by reference, which claims priority to U.S. Provisional
Application Ser. No. 62/097,661 filed Dec. 30, 2014, which is
herein incorporated by reference in its entirety. This application
is also related to co-pending U.S. application Ser. No. 14/979,773
filed on Dec. 28, 2015 and identified by the following Attorney
Docket number and title: 2015EM245-US2 also entitled "Lubricating
Oil Compositions with Engine Wear Protection." This application is
also related to co-pending U.S. application filed on the same date
and identified by the following Attorney Docket number and title:
2015EM391-US3 also entitled "Lubricating Oil Compositions with
Engine Wear Protection."
FIELD
[0002] This disclosure relates to a method for improving wear
control, while maintaining or improving fuel efficiency, in an
engine or other mechanical component lubricated with a lubricating
oil by including a mixture of at least one transition metal salt of
a carboxylic acid (e.g., zinc stearate) and at least one detergent
(i.e., an alkali metal or alkaline earth metal salt of an organic
acid (e.g., calcium salicylate), in the lubricating oil. The
lubricating oils of this disclosure are useful in internal
combustion engines.
BACKGROUND
[0003] A major challenge in engine oil formulation is
simultaneously achieving wear and deposit control, and oxidation
stability, while also maintaining fuel economy performance, over a
broad temperature range.
[0004] Lubricant-related wear control is highly desirable due to
increasing use of low viscosity engine oils for improved fuel
efficiency. As governmental regulations for vehicle fuel
consumption and carbon emissions become more stringent, use of low
viscosity engine oils to meet the regulatory standards is becoming
more prevalent. At the same time, lubricants need to provide a
substantial level of durability and wear protection due to the
formation of thinner lubricant films during engine operation. As
such, use of antiwear additives and friction modifiers in a
lubricant formulation is the typical method for achieving low
friction, wear control and durability. Due to limitations of using
high levels of some antiwears due to catalyst poisoning and deposit
formation, it is highly desirable to find alternative methods for
achieving excellent wear control and durability without poisoning
the catalyst.
[0005] Most current antiwear additives contain phosphorus and/or
sulfur. Zinc dialkyl dithiophosphate (ZDDP) is a common antiwear
additive used in engine lubricants. However, these elements are
known to harm catalysts used to treat exhaust gases from internal
combustion engines, and thus antiwear additives which are free of
sulfur and phosphorus will be advantaged in the marketplace.
[0006] Despite advances in lubricant oil formulation technology,
there exists a need for an engine oil lubricant that effectively
improves wear control while maintaining or improving fuel
efficiency. In addition, there exists a need for an engine oil
lubricant that effectively improves wear control while maintaining
or improving deposit control, oxidation stability and fuel
efficiency.
SUMMARY
[0007] This disclosure relates in part to a method for improving
wear control, while maintaining or improving fuel efficiency, in an
engine or other mechanical component lubricated with a lubricating
oil by including a mixture of at least one transition metal salt of
a carboxylic acid (e.g., zinc stearate) and at least one detergent
(i.e., an alkali metal or alkaline earth metal salt of an organic
acid (e.g., calcium salicylate), in the lubricating oil. The
lubricating oils of this disclosure are useful in internal
combustion engines.
[0008] In an embodiment, wear control is improved and deposit
control, oxidation stability and fuel efficiency are maintained or
improved as compared to wear control, deposit control, oxidation
stability and fuel efficiency achieved using a lubricating oil
containing a minor component other than the (i) at least one
transition metal salt of a carboxylic acid or (ii) the mixture of
at least one transition metal salt of a carboxylic acid and at
least one alkali metal or alkaline earth metal salt of an organic
acid, or at least one alkali metal or alkaline earth metal salt of
an inorganic acid, or at least one alkali metal or alkaline earth
metal salt of a phenol, or mixtures thereof.
[0009] This disclosure also relates in part to a method for
improving wear control, while maintaining or improving fuel
efficiency, in an engine or other mechanical component lubricated
with a lubricating oil by using as the lubricating oil a formulated
oil. The formulated oil has a composition comprising a lubricating
oil base stock as a major component; and at least one metal salt of
a carboxylic acid, as a minor component. The metal salt of the
carboxylic acid contains no sulfur or phosphorus. The metal is
selected from a transition metal and mixtures thereof. The
carboxylic acid is selected from an aliphatic carboxylic acid, a
cycloaliphatic carboxylic acid, an aromatic carboxylic acid, and
mixtures thereof. Wear control is improved and fuel efficiency is
maintained or improved as compared to wear control and fuel
efficiency achieved using a lubricating oil containing a minor
component other than the at least one metal salt of a carboxylic
acid.
[0010] In an embodiment, wear control is improved and deposit
control, oxidation stability and fuel efficiency are maintained or
improved as compared to wear control, deposit control, oxidation
stability and fuel efficiency achieved using a lubricating oil
containing a minor component other than the at least one metal salt
of a carboxylic acid.
[0011] This disclosure further relates in part to a method for
improving wear control, while maintaining or improving fuel
efficiency, in an engine or other mechanical component lubricated
with a lubricating oil by using as the lubricating oil a formulated
oil. The formulated oil has a composition comprising a lubricating
oil base stock as a major component; and a mixture of (i) at least
one metal salt of a carboxylic acid, and (ii) at least one metal
salt of an organic acid, or at least one metal salt of an inorganic
acid, or at least one metal salt of a phenol, or mixtures thereof,
as minor components. For the at least one metal salt of a
carboxylic acid, the metal is selected from a transition metal and
mixtures thereof, and the carboxylic acid is selected from an
aliphatic carboxylic acid, a cycloaliphatic carboxylic acid, an
aromatic carboxylic acid, and mixtures thereof. For the at least
one metal salt of an organic acid, the at least one metal salt of
an inorganic acid, the at least one metal salt of a phenol, or
mixtures thereof, the metal is selected from an alkali metal, an
alkaline earth metal, and mixtures thereof, and the organic or
inorganic acid is selected from an aliphatic organic or inorganic
acid, a cycloaliphatic organic or inorganic acid, an aromatic
organic or inorganic acid, and mixtures thereof. Wear control is
improved and fuel efficiency is maintained or improved as compared
to wear control and fuel efficiency achieved using a lubricating
oil containing minor components other than the mixture of (i) the
at least one metal salt of a carboxylic acid, and (ii) the at least
one metal salt of an organic acid, or the at least one metal salt
of an inorganic acid, or the at least one metal salt of a phenol,
or mixtures thereof.
[0012] In an embodiment, wear control is improved and deposit
control, oxidation stability and fuel efficiency are maintained or
improved as compared to wear control, deposit control, oxidation
stability and fuel efficiency achieved using a lubricating oil
containing minor components other than the mixture of (i) the at
least one metal salt of a carboxylic acid, and (ii) the at least
one metal salt of an organic acid, or the at least one metal salt
of an inorganic acid, or the at least one metal salt of a phenol,
or mixtures thereof.
[0013] This disclosure yet further relates in part to a lubricating
oil (e.g., lubricating engine oil) having a composition comprising
a lubricating oil base stock as a major component, and at least one
metal salt of a carboxylic acid, as a minor component. The metal
salt of the carboxylic acid contains no sulfur or phosphorus. The
metal is selected from a transition metal and mixtures thereof. The
carboxylic acid is selected from an aliphatic carboxylic acid, a
cycloaliphatic carboxylic acid, an aromatic carboxylic acid, and
mixtures thereof. Wear control is improved and fuel efficiency is
maintained or improved as compared to wear control and fuel
efficiency achieved using a lubricating oil containing a minor
component other than the at least one metal salt of a carboxylic
acid.
[0014] In an embodiment, wear control is improved and deposit
control, oxidation stability and fuel efficiency are maintained or
improved as compared to wear control, deposit control, oxidation
stability and fuel efficiency achieved using a lubricating oil
containing a minor component other than the at least one metal salt
of a carboxylic acid.
[0015] This disclosure also relates in part to a lubricating oil
(e.g., lubricating engine oil) having a composition comprising a
lubricating oil base stock as a major component, and a mixture of
(i) at least one metal salt of a carboxylic acid, and (ii) at least
one metal salt of an organic acid, or at least one metal salt of an
inorganic acid, or at least one metal salt of a phenol, or mixtures
thereof, as minor components. For the metal salt of a carboxylic
acid, the metal is selected from a transition metal and mixtures
thereof, and the carboxylic acid is selected from an aliphatic
carboxylic acid, a cycloaliphatic carboxylic acid, an aromatic
carboxylic acid, and mixtures thereof. For the at least one metal
salt of an organic acid, the at least one metal salt of an
inorganic acid, the at least one metal salt of a phenol, or
mixtures thereof, the metal is selected from an alkali metal, an
alkaline earth metal, and mixtures thereof, and the organic or
inorganic acid is selected from a sulfur-containing acid, a
carboxylic acid, a phosphorus-containing acid, and mixtures
thereof. Wear control is improved and fuel efficiency is maintained
or improved as compared to wear control and fuel efficiency
achieved using a lubricating oil containing minor components other
than the mixture of (i) the at least one metal salt of a carboxylic
acid, and (ii) the at least one metal salt of an organic acid, or
the at least one metal salt of an inorganic acid, or the at least
one metal salt of a phenol, or mixtures thereof.
[0016] In an embodiment, wear control is improved and deposit
control, oxidation stability and fuel efficiency are maintained or
improved as compared to wear control, deposit control, oxidation
stability and fuel efficiency achieved using a lubricating oil
containing minor components other than the mixture of (i) the at
least one metal salt of a carboxylic acid, and (ii) the at least
one metal salt of an organic acid, or the at least one metal salt
of an inorganic acid, or the at least one metal salt of a phenol,
or mixtures thereof.
[0017] This disclosure further relates in part to a method for
reducing sulfur and phosphorus and their harmful side effects of
exhaust catalyst poisoning and increased corrosivity in an engine
or other mechanical component lubricated with a lubricating oil by
including (i) at least one transition metal salt of a carboxylic
acid (e.g., zinc stearate) or (ii) a mixture of at least one
transition metal salt of a carboxylic acid (e.g., zinc stearate)
and at least one detergent (i.e., an alkali metal or alkaline earth
metal salt of an organic acid (e.g., calcium salicylate), or an
alkali metal or alkaline earth metal salt of an inorganic acid
(e.g., magnesium sulfonate), or an alkali metal or alkaline earth
metal salt of a phenol, or mixtures thereof), in the lubricating
oil.
[0018] This disclosure yet further relates in part to a low sulfur,
low phosphorus lubricating oil (e.g., lubricating engine oil)
having a composition comprising a lubricating oil base stock as a
major component, and (i) at least one transition metal salt of a
carboxylic acid (e.g., zinc stearate) or (ii) a mixture of at least
one transition metal salt of a carboxylic acid (e.g., zinc
stearate) and at least one detergent (i.e., an alkali metal or
alkaline earth metal salt of an organic acid (e.g., calcium
salicylate), or an alkali metal or alkaline earth metal salt of an
inorganic acid (e.g., magnesium sulfonate), or an alkali metal or
alkaline earth metal salt of a phenol, or mixtures thereof), as a
minor component.
[0019] This disclosure further relates to a method for improving
wear control, while maintaining or improving fuel efficiency, in an
engine or other mechanical component lubricated with a lubricating
oil by using as the lubricating oil a formulated oil, said
formulated oil having a composition comprising a lubricating oil
base stock as a major component; and a mixture as a minor component
of (i) at least one metal salt of a straight chain carboxylic acid,
wherein the metal is selected from the group consisting of
palladium (Pd), silver (Ag), gold (Au), zinc (Zn), and combinations
thereof, and (ii) at least one metal salicylate salt, wherein the
metal is calcium (Ca), magnesium (Mg) or combinations thereof. The
molar ratio of the total metal concentration from the salicylate
salt divided by the total metal concentration from the straight
chain carboxylic acid in the formulated oil ranges from 0.1 to 40,
which improves wear control while maintaining or improving fuel
efficiency as compared to wear control and fuel efficiency achieved
using a lubricating oil containing a minor component other than the
mixture of the at least one metal salt of a straight chain
carboxylic acid and the at least one metal salicylate salt.
[0020] This disclosure further relates to a lubricating oil having
a composition comprising a lubricating oil base stock as a major
component; and a mixture as a minor component of (i) at least one
metal salt of a straight chain carboxylic acid, wherein the metal
is selected from the group consisting of palladium (Pd), silver
(Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at
least one metal salicylate salt, wherein the metal is calcium (Ca),
magnesium (Mg) or combinations thereof. The molar ratio of the
total metal concentration from the salicylate salt divided by the
total metal concentration from the straight chain carboxylic acid
in the formulated oil ranges from 0.1 to 40, which improves wear
control while maintaining or improving fuel efficiency as compared
to wear control and fuel efficiency achieved using a lubricating
oil containing a minor component other than the mixture of the at
least one metal salt of a straight chain carboxylic acid and the at
least one metal salicylate salt.
[0021] It has been surprisingly found that, in accordance with this
disclosure, improvements in wear control are obtained while
maintaining or improving fuel efficiency in an engine or other
mechanical component lubricated with a lubricating oil, by
including a mixture of at least one transition metal salt of a
carboxylic acid and at least one alkali metal or alkaline earth
metal salt of an organic acid, in the lubricating oil. The mixture
of at least one transition metal salt of a carboxylic acid and at
least one alkali metal or alkaline earth metal salt of an organic
acid affords greater improvements in wear control, while
maintaining or improving fuel efficiency, even over the at least
one transition metal salt of a carboxylic acid.
[0022] Further, it has been surprisingly found that, in accordance
with this disclosure, improvements in wear control are obtained
while maintaining or improving deposit control, oxidation stability
and fuel efficiency in an engine or other mechanical component
lubricated with a lubricating oil, by including a mixture of at
least one transition metal salt of a carboxylic acid and at least
one alkali metal or alkaline earth metal salt of an organic acid in
the lubricating oil. The mixture of at least one transition metal
salt of a carboxylic acid and at least one alkali metal or alkaline
earth metal salt of an organic acid affords greater improvements in
wear control, while maintaining or improving deposit control,
oxidation stability and fuel efficiency, even over the at least one
metal salt of a carboxylic acid.
[0023] Furthermore, it has been surprisingly found that in
accordance with this disclosure, improvements in wear control are
obtained while maintaining or improving fuel efficiency in an
engine or other mechanical component lubricated with a lubricating
oil, by including a lubricating oil base stock as a major
component; and a mixture as a minor component of (i) at least one
metal salt of a straight chain carboxylic acid, wherein the metal
is selected from the group consisting of palladium (Pd), silver
(Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at
least one metal salicylate salt, wherein the metal is calcium (Ca),
magnesium (Mg) or combinations thereof. The molar ratio of the
total metal concentration from the salicylate salt divided by the
total metal concentration from the straight chain carboxylic acid
in the formulated oil ranges from 0.1 to 40.
[0024] Other objects and advantages of the present disclosure will
become apparent from the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 (top) shows High Frequency Reciprocating Rig (HFRR)
testing results of a partial formulation in which ZDDP and friction
modifiers were removed ("Partial Formulation"). FIG. 1 (bottom)
shows HFRR testing results for a "Full Formulation" which contains
ZDDP and friction modifiers. FIG. 1 (top and bottom) contain three
lines. Each line is a depth profile of the final wear scar across
the center, right and left of the oval shaped scar.
[0026] FIG. 2 shows the HFRR wear scar data generated when zinc
stearate was added to the "Partial Formulation". The three lines
represent depth profiles of the final wear scar in the center,
right and left of the scar.
[0027] FIG. 3 shows the results of HFRR testing for other metal
carboxylate salts added to the "Partial Formulation" in addition to
zinc stearate in FIG. 2. Results for the "Full Formulation" are
also shown for reference. Some results are averages over several
experiments.
[0028] FIG. 4 shows average friction results versus the ratio of
moles of detergent metal (Ca, Mg) divided by the total moles of
zinc from zinc stearate for both salicylate (inventive) and
sulfonate detergents (comparative).
[0029] FIG. 5 shows average wear results versus the ratio of moles
of detergent metal (Ca, Mg) divided by the total moles of zinc from
zinc stearate for both salicylate detergents (inventive) and
sulfonate detergents (comparative). The wear is measured as the
average of the maximum depth of three profiles taken on the final
wear scar in the center, right and left of the scar.
DETAILED DESCRIPTION
[0030] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art. The phrase "major amount" or "major component" as it
relates to components included within the lubricating oils of the
specification and the claims means greater than or equal to 50 wt.
%, or greater than or equal to 60 wt. %, or greater than or equal
to 70 wt. %, or greater than or equal to 80 wt. %, or greater than
or equal to 90 wt. % based on the total weight of the lubricating
oil. The phrase "minor amount" or "minor component" as it relates
to components included within the lubricating oils of the
specification and the claims means less than 50 wt. %, or less than
or equal to 40 wt. %, or less than or equal to 30 wt. %, or greater
than or equal to 20 wt. %, or less than or equal to 10 wt. %, or
less than or equal to 5 wt. %, or less than or equal to 2 wt. %, or
less than or equal to 1 wt. %, based on the total weight of the
lubricating oil. The phrase "essentially free" as it relates to
components included within the lubricating oils of the
specification and the claims means that the particular component is
at 0 weight % within the lubricating oil, or alternatively is at
impurity type levels within the lubricating oil (less than 100 ppm,
or less than 20 ppm, or less than 10 ppm, or less than 1 ppm). The
phrase "other lubricating oil additives" as used in the
specification and the claims means other lubricating oil additives
that are not specifically recited in the particular section of the
specification or the claims. For example, other lubricating oil
additives may include, but are not limited to, an anti-wear
additive, antioxidant, detergents, dispersant, pour point
depressant, corrosion inhibitor, metal deactivator, seal
compatibility additive, anti-foam agent, inhibitor, anti-rust
additive, friction modifier and combinations thereof.
[0031] It has now been found that improved wear control can be
attained, while fuel efficiency is unexpectedly maintained or
improved, in an engine or other mechanical component lubricated
with a lubricating oil by using as the lubricating oil a formulated
oil that has a mixture of at least one transition metal salt of a
carboxylic acid and at least one alkali metal or alkaline earth
metal salt of an organic acid, in the lubricating oil. The
formulated oil preferably comprises a lubricating oil base stock as
a major component, and a mixture of (i) at least one transition
metal salt of a carboxylic acid and (ii) at least one alkali metal
or alkaline earth metal salt of an organic acid, as minor
components. The lubricating oils of this disclosure are
particularly advantageous as passenger vehicle engine oil (PVEO)
products.
[0032] In an embodiment, wear control is improved and deposit
control, oxidation stability and fuel efficiency are maintained or
improved as compared to wear control, deposit control, oxidation
stability and fuel efficiency achieved using a lubricating oil
containing minor components other than the mixture of at least one
transition metal salt of a carboxylic acid and the at least one
alkali metal or alkaline earth metal salt of an organic acid, as
minor components.
[0033] In one form, the inventive lubricating oils include a
lubricating oil base stock as a major component; and a mixture as a
minor component of (i) at least one metal salt of a straight chain
carboxylic acid, wherein the metal is selected from the group
consisting of palladium (Pd), silver (Ag), gold (Au), zinc (Zn),
and combinations thereof, and the straight chain carboxylic acid is
stearic acid, palmitic acid or combinations thereof, and (ii) at
least one metal salicylate salt, wherein the metal is calcium (Ca),
magnesium (Mg) or combinations thereof. The molar ratio of the
total metal concentration from the salicylate salt divided by the
total metal concentration from the straight chain carboxylic acid
ranges from 0.1 to 40. The inventive lubricating oils provide
improved wear control and fuel efficiency is improved or maintained
as compared to wear control and fuel efficiency achieved using a
lubricating oil containing a minor component other than the mixture
of the at least one metal salt of a straight chain carboxylic acid
and the at least one metal salicylate salt.
[0034] For the inventive lubricating oils of this disclosure, the
molar ratio of the total metal concentration from the salicylate
salt divided by the total metal concentration from the straight
chain carboxylic acid may alternatively range from 0.2 to 30, or
from 0.3 to 20, or from 0.4 to 10, or from 0.5 to 5. The method to
measure the elements included in the table for low phosphorus
content uses an inductively coupled plasma (ICP) technique
according to ASTM D5185. The results are obtained in ppm by weight.
The molar Zn/P ratios were calculated using the atomic weight of
zinc and phosphorus of 65.38 and 30.97 g/mole respectively.
[0035] The instant disclosure also provides a method for improving
wear control, while maintaining or improving fuel efficiency, in an
engine or other mechanical component lubricated with a lubricating
oil by using as the lubricating oil a formulated oil, said
formulated oil having a composition comprising a lubricating oil
base stock as a major component; and a mixture as a minor component
of (i) at least one metal salt of a straight chain carboxylic acid,
wherein the metal is selected from the group consisting of
palladium (Pd), silver (Ag), gold (Au), zinc (Zn), and combinations
thereof, and the straight chain carboxylic acid is stearic acid,
palmitic acid or combinations thereof, and (ii) at least one metal
salicylate salt, wherein the metal is calcium (Ca), magnesium (Mg)
or combinations thereof. The molar ratio of the total metal
concentration from the salicylate salt divided by the total metal
concentration from the straight chain carboxylic acid ranges from
0.1 to 40, or 0.2 to 30, or 0.3 to 20, or 0.4 to 10, or 0.5 to 5.
Using the method, the wear control is improved and fuel efficiency
is maintained or improved as compared to wear control and fuel
efficiency achieved using a lubricating oil containing a minor
component other than the mixture of the at least one metal salt of
a straight chain carboxylic acid and the at least one metal
salicylate salt.
[0036] The lubricating oils of this disclosure including a metal
salt of a carboxylic acid that contains no sulfur or phosphorus
means that the metal salt of a carboxylic acid is essentially free
of sulfur and phosphorus. Essentially free for the purpose of the
sulfur and phosphorus level in the metal salt of a carboxylic acid
means that the sulfur and phosphorus is at 0 weight % within the
metal salt of the carboxylic acid, or alternatively are at impurity
type levels within the metal salt of the carboxylic acid (less than
100 ppm, or less than 20 ppm, or less than 10 ppm, or less than 1
ppm).
[0037] In addition, the lubricating oils of this disclosure can be
useful as commercial vehicle engine oil products (e.g., heavy duty
lubricants). In particular, the lubricating oils of this disclosure
can be useful for reducing wear in high soot content lubricants and
diesel oils.
[0038] The lubricating oils of this disclosure provide excellent
engine protection including antiwear performance. This benefit has
been demonstrated for the lubricating oils of this disclosure in
the Sequence IIIG engine tests. The low viscosity lubricating oils
of this disclosure provide improved fuel efficiency.
[0039] The lubricating engine oils of this disclosure have a
composition sufficient to pass wear protection requirements of one
or more engine tests selected from Sequence IIIG and others.
[0040] The present disclosure provides lubricant compositions with
excellent antiwear properties. Antiwear additives are generally
required for reducing wear in operating equipment where two solid
surfaces engage in contact. In the absence of antiwear chemistry,
the surfaces can rub together causing material loss on one or both
surfaces which can eventually lead to equipment malfunction and
failure. Antiwear additives can produce a protective surface layer
which reduces wear and material loss. Most commonly the materials
of interest are metals such as steel. However, other material such
as ceramics, polymer coatings, diamond-like carbon, and the like
can also be used to produce durable surfaces in modern equipment.
The lubricant compositions of this disclosure can provide antiwear
properties to such surfaces.
[0041] As used herein, an inorganic acid refers to a sulfonic acid,
a phosphoric acid, a phosphonic acid, and other
heteroatom-containing acids. Also, as used herein, inorganic acid
refers to hydrocarbon-containing derivatives of the inorganic
acids.
[0042] The lubricant compositions of this disclosure provide
advantaged wear, including advantaged wear and friction,
performance in the lubrication of internal combustion engines,
power trains, drivelines, transmissions, gears, gear trains, gear
sets, compressors, pumps, hydraulic systems, bearings, bushings,
turbines, and the like.
[0043] Also, the lubricant compositions of this disclosure provide
advantaged wear, including advantaged wear and friction,
performance in the lubrication of mechanical components, which can
include, for example, pistons, piston rings, cylinder liners,
cylinders, cams, tappets, lifters, bearings (journal, roller,
tapered, needle, ball, and the like), gears, valves, and the
like.
[0044] Further, the lubricant compositions of this disclosure
provide advantaged wear, including advantaged wear and friction,
performance as a component in lubricant compositions, which can
include, for example, lubricating liquids, semi-solids, solids,
greases, dispersions, suspensions, material concentrates, additive
concentrates, and the like.
[0045] The lubricant compositions of this disclosure are useful in
additive concentrates that include the combination of the minor
component of this disclosure with at least one other additive
component, having combined weight % concentrations in the range of
1% to 80%, preferably 2% to 60%, more preferably 3% to 50%, even
more preferably 4% to 40%, and in some instances preferably 5% to
30%.
[0046] Yet further, the lubricant compositions of this disclosure
provide advantaged wear, including advantaged wear and friction,
performance under diverse lubrication regimes, that include, for
example, hydrodynamic, elastohydrodynamic, boundary, mixed
lubrication, extreme pressure regimes, and the like.
[0047] The lubricant compositions of this disclosure provide
advantaged wear, including advantaged wear and friction,
performance under a range of lubrication contact pressures, from 1
MPas to greater than 10 GPas, preferably greater than 10 MPas, more
preferably greater that 100 MPas, even more preferably greater than
300 MPas. Under certain circumstances, the lubricant compositions
of this disclosure provide advantaged wear, including advantaged
wear and friction, performance at greater than 0.5 GPas, often at
greater than 1 GPas, sometimes greater than 2 GPas, under selected
circumstances greater than 5 GPas.
[0048] Also, the lubricant compositions of this disclosure provide
advantaged wear, including advantaged wear and friction,
performance in spark-ignition internal combustion engines,
compression-ignition internal combustion engines, mixed-ignition
(spark-assisted and compression) internal combustion engines, jet-
or plasma-ignition internal combustion engines, and the like.
[0049] Further, the lubricant compositions of this disclosure
provide advantaged wear, including advantaged wear and friction,
performance in diverse engine types, which can include, for
example, the following: 2-stroke engines; 4-stroke engine; engines
with alternate stroke designs greater than 2-stroke, such as
5-stroke, or 7-stroke, and the like; rotary engines; dedicated EGR
(exhaust gas recirculation) fueled engines; free-piston engine;
engines that function in hybrid propulsion systems, that can
further include electrical-based power systems, hydraulic-based
power systems, diverse system designs such as parallel, series,
non-parallel, and the like.
[0050] Yet further, the lubricant compositions of this disclosure
provide advantaged wear, including advantaged wear and friction,
performance in, for example, the following: naturally aspirated
engines; turbocharged and supercharged, port-fueled injection
engines; turbocharged and supercharged, direct injection engines
(for gasoline, diesel, natural gas, and other fuel types);
turbocharged engines designed to operate with in-cylinder
combustion pressures of greater than 12 bar, preferably greater
than 18 bar, more preferably greater than 20 bar, even more
preferably greater than 22 bar, and in certain instances combustion
pressures greater than 24 bar, even greater than 26 bar, and even
more so greater than 28 bar, and with particular designs greater
than 30 bar; engines having low-temperature burn combustion,
lean-burn combustion, and high thermal efficiency designs.
[0051] Also, the lubricant compositions of this disclosure provide
advantaged wear, including advantaged wear and friction,
performance in engines that are fueled with fuel compositions that
include, for example, the following: gasoline; distillate fuel,
diesel fuel, jet fuel, gas-to-liquid and Fischer-Tropsch-derived
high-cetane fuels; compressed natural gas, liquefied natural gas,
methane, ethane, propane, other natural gas components, other
natural gas liquids; ethanol, methanol, other higher MW alcohols;
FAMEs, vegetable-derived esters and polyesters; biodiesel,
bio-derived and bio-based fuels; hydrogen; dimethyl ether; other
alternate fuels; fuels diluted with EGR (exhaust gas recirculation)
gases, with EGR gases enriched in hydrogen or carbon monoxide or
combinations of H.sub.2/CO, in both dilute and high concentration
(in concentrations of >0.1%, preferably >0.5%, more
preferably >1%, even more preferably >2%, and even more so
preferably >3%), and blends or combinations of these in
proportions that enhance combustion efficiency, power, cleanliness,
anti-knock, and anti-LSPI (low speed pre-ignition).
[0052] Further, the lubricant compositions of this disclosure
provide advantaged wear, including advantaged wear and friction,
performance on lubricated surfaces that include, for example, the
following: metals, metal alloys, non-metals, non-metal alloys,
mixed carbon-metal composites and alloys, mixed carbon-nonmetal
composites and alloys, ferrous metals, ferrous composites and
alloys, non-ferrous metals, non-ferrous composites and alloys,
titanium, titanium composites and alloys, aluminum, aluminum
composites and alloys, magnesium, magnesium composites and alloys,
ion-implanted metals and alloys, plasma modified surfaces; surface
modified materials; coatings; mono-layer, multi-layer, and gradient
layered coatings; honed surfaces; polished surfaces; etched
surfaces; textured surfaces; mircro and nano structures on textured
surfaces; super-finished surfaces; diamond-like carbon (DLC), DLC
with high-hydrogen content, DLC with moderate hydrogen content, DLC
with low-hydrogen content, DLC with near-zero hydrogen content, DLC
composites, DLC-metal compositions and composites, DLC-nonmetal
compositions and composites; ceramics, ceramic oxides, ceramic
nitrides, FeN, CrN, ceramic carbides, mixed ceramic compositions,
and the like; polymers, thermoplastic polymers, engineered
polymers, polymer blends, polymer alloys, polymer composites;
materials compositions and composites containing dry lubricants,
that include, for example, graphite, carbon, molybdenum, molybdenum
disulfide, polytetrafluoroethylene, polyperfluoropropylene,
polyperfluoroalkylethers, and the like.
[0053] Yet further, the lubricant compositions of this disclosure
provide advantaged wear, including advantaged wear and friction,
performance on lubricated surfaces of 3-D printed materials, with
or without post-printing surface finishing; surfaces of 3-D printed
materials that have been post-printing treated with coatings, which
may include plasma spray coatings, ion beam-generated coatings,
electrolytically- or galvanically-generated coatings,
electro-deposition coatings, vapor-deposition coatings,
liquid-deposition coatings, thermal coatings, laser-based coatings;
surfaces of 3-D printed materials, where the surfaces may be
as-printed, finished, or coated, that include: metals, metal
alloys, non-metals, non-metal alloys, mixed carbon-metal composites
and alloys, mixed carbon-nonmetal composites and alloys, ferrous
metals, ferrous composites and alloys, non-ferrous metals,
non-ferrous composites and alloys, titanium, titanium composites
and alloys, aluminum, aluminum composites and alloys, magnesium,
magnesium composites and alloys, ion-implanted metals and alloys;
plasma modified surfaces; surface modified materials; mono-layer,
multi-layer, and gradient layered coatings; honed surfaces;
polished surfaces; etched surfaces; textured surfaces; mircro and
nano structures on textured surfaces; super-finished surfaces;
diamond-like carbon (DLC), DLC with high-hydrogen content, DLC with
moderate hydrogen content, DLC with low-hydrogen content, DLC with
near-zero hydrogen content, DLC composites, DLC-metal compositions
and composites, DLC-nonmetal compositions and composites; ceramics,
ceramic oxides, ceramic nitrides, FeN, CrN, ceramic carbides, mixed
ceramic compositions, and the like; polymers, thermoplastic
polymers, engineered polymers, polymer blends, polymer alloys,
polymer composites; materials compositions and composites
containing dry lubricants, that include, for example, graphite,
carbon, molybdenum, molybdenum disulfide, polytetrafluoroethylene,
polyperfluoropropylene, polyperfluoroalkylethers, and the like.
[0054] Still further, the lubricant compositions of this disclosure
provide advantaged synergistic wear, including advantaged
synergistic wear and friction, performance in combination with one
or more performance additives, with performance additives at
effective concentration ranges, and with performance additives at
effective ratios with the minor component of this disclosure.
Lubricating Oil Base Stocks
[0055] A wide range of lubricating base oils is known in the art.
Lubricating base oils that are useful in the present disclosure are
natural oils, mineral oils and synthetic oils, and unconventional
oils (or mixtures thereof) can be used unrefined, refined, or
rerefined (the latter is also known as reclaimed or reprocessed
oil). Unrefined oils are those obtained directly from a natural or
synthetic source and used without added purification. These include
shale oil obtained directly from retorting operations, petroleum
oil obtained directly from primary distillation, and ester oil
obtained directly from an esterification process. Refined oils are
similar to the oils discussed for unrefined oils except refined
oils are subjected to one or more purification steps to improve at
least one lubricating oil property. One skilled in the art is
familiar with many purification processes. These processes include
solvent extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as a feed stock.
[0056] Groups I, II, III, IV and V are broad base oil stock
categories 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 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
have a viscosity index of between about 80 to 120, and contain less
than or equal to about 0.03% sulfur and greater than or equal to
about 90% saturates. Group III stocks have a viscosity index
greater than about 120 and contain less than or equal to about
0.03% sulfur and greater than about 90% saturates. Group IV
includes polyalphaolefins (PAO). Group V base stock includes base
stocks not included in Groups I-IV. The table below summarizes
properties of each of these five groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I .sup. <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
[0057] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source, for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful. Natural oils vary also
as to the method used for their production and purification, for
example, their distillation range and whether they are straight run
or cracked, hydrorefined, or solvent extracted.
[0058] Group II and/or Group III hydroprocessed or hydrocracked
base stocks, including synthetic oils such as alkyl aromatics and
synthetic esters are also well known base stock oils.
[0059] Synthetic oils include hydrocarbon oil. Hydrocarbon oils
include oils such as polymerized and interpolymerized olefins
(polybutylenes, polypropylenes, propylene isobutylene copolymers,
ethylene-olefin copolymers, and ethylene-alphaolefin copolymers,
for example). Polyalphaolefin (PAO) oil base stocks are commonly
used synthetic hydrocarbon oil. By way of example, PAOs derived
from C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or mixtures
thereof may be utilized. See U.S. Pat. Nos. 4,956,122; 4,827,064;
and 4,827,073.
[0060] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron
Phillips Chemical Company, BP, and others, typically vary from
about 250 to about 3,000, although PAO's may be made in viscosities
up to about 150 cSt (100.degree. C.). The PAOs are typically
comprised of relatively low molecular weight hydrogenated polymers
or oligomers of alphaolefins which include, but are not limited to,
C.sub.2 to about C.sub.32 alphaolefins with the C.sub.8 to about
C.sub.16 alphaolefins, such as 1-octene, 1-decene, 1-dodecene and
the like, being preferred. The preferred polyalphaolefins are
poly-1-octene, poly-1-decene and poly-1-dodecene and mixtures
thereof and mixed olefin-derived polyolefins. However, the dimers
of higher olefins in the range of C.sub.14 to Cis may be used to
provide low viscosity base stocks of acceptably low volatility.
Depending on the viscosity grade and the starting oligomer, the
PAOs may be predominantly trimers and tetramers of the starting
olefins, with minor amounts of the higher oligomers, having a
viscosity range of 1.5 to 12 cSt. PAO fluids of particular use may
include 3.0 cSt, 3.4 cSt, and/or 3.6 cSt and combinations thereof.
Mixtures of PAO fluids having a viscosity range of 1.5 to
approximately 150 cSt or more may be used if desired.
[0061] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. No. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C.sub.14 to C.sub.18
olefins are described in U.S. Pat. No. 4,218,330.
[0062] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof. Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (LHDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269, the disclosure of which is incorporated
herein by reference in its entirety. Processes for making
hydrocracked/hydroi somerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Each of the aforementioned patents is incorporated
herein in their entirety. Particularly favorable processes are
described in European Patent Application Nos. 464546 and 464547,
also incorporated herein by reference. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. Nos. 4,594,172
and 4,943,672, the disclosures of which are incorporated herein by
reference in their entirety.
[0063] Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived
base oils, and other wax-derived hydroisomerized (wax isomerate)
base oils be advantageously used in the instant disclosure, and may
have useful kinematic viscosities at 100.degree. C. of about 3 cSt
to about 50 cSt, preferably about 3 cSt to about 30 cSt, more
preferably about 3.5 cSt to about 25 cSt, as exemplified by GTL 4
with kinematic viscosity of about 4.0 cSt at 100.degree. C. and a
viscosity index of about 141. These Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and other wax-derived
hydroisomerized base oils may have useful pour points of about
-20.degree. C. or lower, and under some conditions may have
advantageous pour points of about -25.degree. C. or lower, with
useful pour points of about -30.degree. C. to about -40.degree. C.
or lower. Useful compositions of Gas-to-Liquids (GTL) base oils,
Fischer-Tropsch wax derived base oils, and wax-derived
hydroisomerized base oils are recited in U.S. Pat. Nos. 6,080,301;
6,090,989, and 6,165,949 for example, and are incorporated herein
in their entirety by reference.
[0064] The hydrocarbyl aromatics can be used as a base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least about 5% of its weight derived from an aromatic moiety such
as a benzenoid moiety or naphthenoid moiety, or their derivatives.
These hydrocarbyl aromatics include alkyl benzenes, alkyl
naphthalenes, alkyl diphenyl oxides, alkyl naphthols, alkyl
diphenyl sulfides, alkylated bis-phenol A, alkylated thiodiphenol,
and the like. The aromatic can be mono-alkylated, dialkylated,
polyalkylated, and the like. The aromatic can be mono- or
poly-functionalized. The hydrocarbyl groups can also be comprised
of mixtures of alkyl groups, alkenyl groups, alkynyl, cycloalkyl
groups, cycloalkenyl groups and other related hydrocarbyl groups.
The hydrocarbyl groups can range from about C.sub.6 up to about
C.sub.60 with a range of about C.sub.8 to about C.sub.20 often
being preferred. A mixture of hydrocarbyl groups is often
preferred, and up to about three such substituents may be present.
The hydrocarbyl group can optionally contain sulfur, oxygen, and/or
nitrogen containing substituents. The aromatic group can also be
derived from natural (petroleum) sources, provided at least about
5% of the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to about 50
cSt are preferred, with viscosities of approximately 3.4 cSt to
about 20 cSt often being more preferred for the hydrocarbyl
aromatic component. In one embodiment, an alkyl naphthalene where
the alkyl group is primarily comprised of 1-hexadecene is used.
Other alkylates of aromatics can be advantageously used.
Naphthalene or methyl naphthalene, for example, can be alkylated
with olefins such as octene, decene, dodecene, tetradecene or
higher, mixtures of similar olefins, and the like. Useful
concentrations of hydrocarbyl aromatic in a lubricant oil
composition can be about 2% to about 25%, preferably about 4% to
about 20%, and more preferably about 4% to about 15%, depending on
the application.
[0065] Alkylated aromatics such as the hydrocarbyl aromatics of the
present disclosure may be produced by well-known Friedel-Crafts
alkylation of aromatic compounds. See Friedel-Crafts and Related
Reactions, Olah, G. A. (ed.), Inter-science Publishers, New York,
1963. For example, an aromatic compound, such as benzene or
naphthalene, is alkylated by an olefin, alkyl halide or alcohol in
the presence of a Friedel-Crafts catalyst. See Friedel-Crafts and
Related Reactions, Vol. 2, part 1, chapters 14, 17, and 18, See
Olah, G. A. (ed.), Inter-science Publishers, New York, 1964. Many
homogeneous or heterogeneous, solid catalysts are known to one
skilled in the art. The choice of catalyst depends on the
reactivity of the starting materials and product quality
requirements. For example, strong acids such as AlCl.sub.3,
BF.sub.3, or HF may be used. In some cases, milder catalysts such
as FeCl.sub.3 or SnCl.sub.4 are preferred. Newer alkylation
technology uses zeolites or solid super acids.
[0066] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0067] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols (such as the neopentyl polyols, e.g.,
neopentyl glycol, trimethylol ethane,
2-methyl-2-propyl-1,3-propanediol, trimethylol propane,
pentaerythritol and dipentaerythritol) with alkanoic acids
containing at least about 4 carbon atoms, preferably C.sub.5 to
C.sub.30 acids such as saturated straight chain fatty acids
including caprylic acid, capric acid, lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures of any of these materials.
[0068] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
monocarboxylic acids containing from about 5 to about 10 carbon
atoms. These esters are widely available commercially, for example,
the Mobil P-41 and P-51 esters of ExxonMobil Chemical Company.
[0069] Also useful are esters derived from renewable material such
as coconut, palm, rapeseed, soy, sunflower and the like. These
esters may be monoesters, di-esters, polyol esters, complex esters,
or mixtures thereof. These esters are widely available
commercially, for example, the Esterex NP 343 ester of ExxonMobil
Chemical Company.
[0070] Engine oil formulations containing renewable esters are
included in this disclosure. For such formulations, the renewable
content of the ester is typically greater than about 70 weight
percent, preferably more than about 80 weight percent and most
preferably more than about 90 weight percent.
[0071] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0072] Non-conventional or unconventional base stocks/base oils
include one or more of a mixture of base stock(s) derived from one
or more Gas-to-Liquids (GTL) materials, as well as
isomerate/isodewaxate base stock(s) derived from natural wax or
waxy feeds, mineral and or non-mineral oil waxy feed stocks such as
slack waxes, natural waxes, and waxy stocks such as gas oils, waxy
fuels hydrocracker bottoms, waxy raffinate, hydrocrackate, thermal
crackates, or other mineral, mineral oil, or even non-petroleum oil
derived waxy materials such as waxy materials received from coal
liquefaction or shale oil, and mixtures of such base stocks.
[0073] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds and/or elements as feed
stocks such as hydrogen, carbon dioxide, carbon monoxide, water,
methane, ethane, ethylene, acetylene, propane, propylene, propyne,
butane, butylenes, and butynes. GTL base stocks and/or base oils
are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons; for example, waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feed stocks. GTL base stock(s) and/or base oil(s)
include oils boiling in the lube oil boiling range (1)
separated/fractionated from synthesized GTL materials such as, for
example, by distillation and subsequently subjected to a final wax
processing step which involves either or both of a catalytic
dewaxing process, or a solvent dewaxing process, to produce lube
oils of reduced/low pour point; (2) synthesized wax isomerates,
comprising, for example, hydrodewaxed or hydroisomerized cat and/or
solvent dewaxed synthesized wax or waxy hydrocarbons; (3)
hydrodewaxed or hydroisomerized cat and/or solvent dewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates); preferably
hydrodewaxed or hydroisomerized/followed by cat and/or solvent
dewaxing dewaxed F-T waxy hydrocarbons, or hydrodewaxed or
hydroisomerized/followed by cat (or solvent) dewaxing dewaxed, F-T
waxes, or mixtures thereof.
[0074] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from about 2 mm.sup.2/s to about 50 mm.sup.2/s
(ASTM D445). They are further characterized typically as having
pour points of -5.degree. C. to about -40.degree. C. or lower (ASTM
D97). They are also characterized typically as having viscosity
indices of about 80 to about 140 or greater (ASTM D2270).
[0075] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) typically have very low sulfur and
nitrogen content, generally containing less than about 10 ppm, and
more typically less than about 5 ppm of each of these elements. The
sulfur and nitrogen content of GTL base stock(s) and/or base oil(s)
obtained from F-T material, especially F-T wax, is essentially nil.
In addition, the absence of phosphorus and aromatics make this
materially especially suitable for the formulation of low SAP
products.
[0076] The term GTL base stock and/or base oil and/or wax isomerate
base stock and/or base oil is to be understood as embracing
individual fractions of such materials of wide viscosity range as
recovered in the production process, mixtures of two or more of
such fractions, as well as mixtures of one or two or more low
viscosity fractions with one, two or more higher viscosity
fractions to produce a blend wherein the blend exhibits a target
kinematic viscosity.
[0077] The GTL material, from which the GTL base stock(s) and/or
base oil(s) is/are derived is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0078] Base oils for use in the formulated lubricating oils useful
in the present disclosure are any of the variety of oils
corresponding to API Group I, Group II, Group III, Group IV, and
Group V oils and mixtures thereof, preferably API Group II, Group
III, Group IV, and Group V oils and mixtures thereof, more
preferably the Group III to Group V base oils due to their
exceptional volatility, stability, viscometric and cleanliness
features. Minor quantities of Group I stock, such as the amount
used to dilute additives for blending into formulated lube oil
products, can be tolerated but should be kept to a minimum, i.e.
amounts only associated with their use as diluent/carrier oil for
additives used on an "as-received" basis. Even in regard to the
Group II stocks, it is preferred that the Group II stock be in the
higher quality range associated with that stock, i.e. a Group II
stock having a viscosity index in the range 100<VI<120.
[0079] The base oil constitutes the major component of the engine
oil lubricant composition of the present disclosure and typically
is present in an amount ranging from about 50 to about 99 weight
percent, preferably from about 70 to about 95 weight percent, and
more preferably from about 85 to about 95 weight percent, based on
the total weight of the composition. The base oil may be selected
from any of the synthetic or natural oils typically used as
crankcase lubricating oils for spark-ignited and
compression-ignited engines. The base oil conveniently has a
kinematic viscosity, according to ASTM standards, of about 2.5 cSt
to about 12 cSt (or mm.sup.2/s) at 100.degree. C. and preferably of
about 2.5 cSt to about 9 cSt (or mm.sup.2/s) at 100.degree. C.
Mixtures of synthetic and natural base oils may be used if desired.
Bi-modal mixtures of Group I, II, III, IV, and/or V base stocks may
be used if desired.
Antiwear Additive
[0080] Illustrative antiwear additives useful in this disclosure
include, for example, metal salts of a carboxylic acid. The metal
is selected from a transition metal and mixtures thereof. The
carboxylic acid is selected from an aliphatic carboxylic acid, a
cycloaliphatic carboxylic acid, an aromatic carboxylic acid, and
mixtures thereof.
[0081] The metal is preferably selected from a Group 10, 11 and 12
metal, and mixtures thereof. The carboxylic acid is preferably an
aliphatic, saturated, unbranched carboxylic acid having from about
8 to about 26 carbon atoms, and mixtures thereof.
[0082] The metal is preferably selected from nickel (Ni), palladium
(Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc
(Zn), and mixtures thereof.
[0083] The carboxylic acid is preferably selected from caprylic
acid (C8), pelargonic acid (C9), capric acid (C10), undecylic acid
(C11), lauric acid (C12), tridecylic acid (C13), myristic acid
(C14), pentadecylic acid (C15), palmitic acid (C16), margaric acid
(C17), isostearic acid (C18), stearic acid (C18), nonadecylic acid
(C19), arachidic acid (C20), heneicosylic acid (C21), behenic acid
(C22), tricosylic acid (C23), lignoceric acid (C24), pentacosylic
acid (C25), cerotic acid (C26), and mixtures thereof.
[0084] Preferably, the metal salt of a carboxylic acid comprises
zinc stearate, silver stearate, palladium stearate, zinc palmitate,
silver palmitate, palladium palmitate, and mixtures thereof.
[0085] The metal salt of a carboxylic acid is present in the engine
oil formulations of this disclosure in an amount of from about 0.01
weight percent to about 5 weight percent, based on the total weight
of the formulated oil.
[0086] Low phosphorus engine oil formulations are included in this
disclosure. For such formulations, the phosphorus content is
typically less than about 0.12 weight percent, preferably less than
about 0.10 weight percent, more preferably less than about 0.085
weight percent, and most preferably less than about 0.04 weight
percent.
Detergents
[0087] Illustrative detergents useful in this disclosure include,
for example, alkali metal detergents, alkaline earth metal
detergents, or mixtures of one or more alkali metal detergents and
one or more alkaline earth metal detergents. A typical detergent is
an anionic material that contains a long chain hydrophobic portion
of the molecule and a smaller anionic or oleophobic hydrophilic
portion of the molecule. The anionic portion of the detergent is
typically derived from an organic acid such as a sulfur-containing
acid, carboxylic acid (e.g., salicylic acid), phosphorus-containing
acid, phenol, or mixtures thereof. The counterion is typically an
alkaline earth or alkali metal. The detergent can be overbased as
described herein.
[0088] The detergent is preferably a metal salt of an organic or
inorganic acid, a metal salt of a phenol, or mixtures thereof. The
metal is preferably selected from an alkali metal, an alkaline
earth metal, and mixtures thereof. The organic or inorganic acid is
selected from an aliphatic organic or inorganic acid, a
cycloaliphatic organic or inorganic acid, an aromatic organic or
inorganic acid, and mixtures thereof.
[0089] The metal is preferably selected from an alkali metal, an
alkaline earth metal, and mixtures thereof. More preferably, the
metal is selected from calcium (Ca), magnesium (Mg), and mixtures
thereof.
[0090] The organic acid or inorganic acid is preferably selected
from a sulfur-containing acid, a carboxylic acid, a
phosphorus-containing acid, and mixtures thereof.
[0091] Preferably, the metal salt of an organic or inorganic acid
or the metal salt of a phenol comprises calcium phenate, calcium
sulfonate, calcium salicylate, magnesium phenate, magnesium
sulfonate, magnesium salicylate, an overbased detergent, and
mixtures thereof. Preferably the metal salt of the organic acid or
the inorganic acid or the phenol is overbased. Most preferably the
salts are overbased with carbonate.
[0092] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased. These detergents can be used in
mixtures of neutral, overbased, highly overbased calcium
salicylate, sulfonates, phenates and/or magnesium salicylate,
sulfonates, phenates. The TBN ranges can vary from low, medium to
high TBN products, including as low as 0 to as high as 600, or 50
to 500, or 100 to 400, or 200 to 400. Preferably the TBN delivered
by the detergent is between 1 and 20. More preferably between 1 and
12. Mixtures of low, medium, high TBN can be used, along with
mixtures of calcium and magnesium metal based detergents, and
including sulfonates, phenates, salicylates, and carboxylates. A
detergent mixture with a metal ratio of 1, in conjunction of a
detergent with a metal ratio of 2, and as high as a detergent with
a metal ratio of 5, can be used. Borated detergents can also be
used.
[0093] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH).sub.2, BaO, Ba(OH).sub.2,
MgO, Mg(OH).sub.2, for example) with an alkyl phenol or sulfurized
alkylphenol. Useful alkyl groups 15 include straight chain or
branched C.sub.1-C.sub.30 alkyl groups, preferably,
C.sub.4-C.sub.20 or mixtures thereof. Examples of suitable phenols
include isobutylphenol, 2-ethylhexylphenol, nonylphenol, dodecyl
phenol, and the like. It should be noted that starting alkylphenols
may contain more than one alkyl substituent that are each
independently straight chain or branched and can be used from 0.5
to 6 weight percent. When a non-sulfurized alkylphenol is used, the
sulfurized product may be obtained by methods well known in the
art. These methods include heating a mixture of alkylphenol and
sulfurizing agent (including elemental sulfur, sulfur halides such
as sulfur dichloride, and the like) and then reacting the
sulfurized phenol with an alkaline earth metal base.
[0094] In accordance with this disclosure, metal salts of
carboxylic acids are preferred detergents. These carboxylic acid
detergents may be prepared by reacting a basic metal compound with
at least one carboxylic acid and removing free water from the
reaction product. These compounds may be overbased to produce the
desired TBN level. Detergents made from salicylic acid are one
preferred class of detergents derived from carboxylic acids. Useful
salicylates include long chain alkyl salicylates. One useful family
of compositions is of the formula
##STR00001##
where R is an alkyl group having 1 to about 30 carbon atoms, n is
an integer from 1 to 4, and M is an alkaline earth metal. Preferred
R groups are alkyl chains of at least C.sub.11, preferably C.sub.13
or greater. R may be optionally substituted with substituents that
do not interfere with the detergent's function. M is preferably,
calcium, magnesium, or barium. More preferably, M is calcium.
[0095] 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.
[0096] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0097] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039.
[0098] Preferred detergents include calcium sulfonates, magnesium
sulfonates, calcium salicylates, magnesium salicylates, calcium
phenates, magnesium phenates, and other related components
(including borated detergents), and mixtures thereof. Preferred
mixtures of detergents include magnesium sulfonate and calcium
salicylate, magnesium sulfonate and calcium sulfonate, magnesium
sulfonate and calcium phenate, calcium phenate and calcium
salicylate, calcium phenate and calcium sulfonate, calcium phenate
and magnesium salicylate, calcium phenate and magnesium phenate.
Overbased detergents are also preferred.
[0099] The detergent concentration in the lubricating oils of this
disclosure can range from about 0.5 to about 6.0 weight percent,
preferably about 0.6 to 5.0 weight percent, and more preferably
from about 0.8 weight percent to about 4.0 weight percent, based on
the total weight of the lubricating oil.
[0100] As used herein, the detergent concentrations are given on an
"as delivered" basis. Typically, the active detergent is delivered
with a process oil. The "as delivered" detergent typically contains
from about 20 weight percent to about 100 weight percent, or from
about 40 weight percent to about 60 weight percent, of active
detergent in the "as delivered" detergent product.
Other Additives
[0101] The formulated lubricating oil useful in the present
disclosure may additionally contain one or more of the other
commonly used lubricating oil performance additives including but
not limited to other antiwear additives, dispersants, viscosity
modifiers, corrosion inhibitors, rust inhibitors, metal
deactivators, extreme pressure additives, anti-seizure agents, wax
modifiers, other viscosity modifiers, fluid-loss additives, seal
compatibility agents, lubricity agents, anti-staining agents,
chromophoric agents, defoamants, demulsifiers, emulsifiers,
densifiers, wetting agents, gelling agents, tackiness agents,
colorants, and others. For a review of many commonly used
additives, see Klamann in Lubricants and Related Products, Verlag
Chemie, Deerfield Beach, Fla.; ISBN 0-89573-177-0. Reference is
also made to "Lubricant Additives" by M. W. Ranney, published by
Noyes Data Corporation of Parkridge, N J (1973); see also U.S. Pat.
No. 7,704,930, the disclosure of which is incorporated herein in
its entirety. These additives are commonly delivered with varying
amounts of diluent oil, that may range from 5 weight percent to 50
weight percent.
[0102] The additives useful in this disclosure do not have to be
soluble in the lubricating oils. Insoluble additives such as zinc
stearate in oil can be dispersed in the lubricating oils of this
disclosure.
[0103] The types and quantities of performance additives used in
combination with the instant disclosure in lubricant compositions
are not limited by the examples shown herein as illustrations.
Other Antiwear Additives
[0104] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) can be a useful component of
the lubricating oils of this disclosure. ZDDP can be derived from
primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.2
where R.sup.1 and R.sup.2 are C.sub.1-C.sub.18 alkyl groups,
preferably C.sub.2-C.sub.12 alkyl groups. These alkyl groups may be
straight chain or branched. Alcohols used in the ZDDP can be
2-propanol, butanol, secondary butanol, pentanols, hexanols such as
4-methyl-2-pentanol, n-hexanol, n-octanol, 2-ethyl hexanol,
alkylated phenols, and the like. Mixtures of secondary alcohols or
of primary and secondary alcohol can be preferred. Alkyl aryl
groups may also be used.
[0105] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 677A", "LZ 1095" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "HITEC
7169".
[0106] The ZDDP is typically used in amounts of from about 0.4
weight percent to about 1.2 weight percent, preferably from about
0.5 weight percent to about 1.0 weight percent, and more preferably
from about 0.6 weight percent to about 0.8 weight percent, based on
the total weight of the lubricating oil, although more or less can
often be used advantageously. Preferably, the ZDDP is a secondary
ZDDP and present in an amount of from about 0.6 to 1.0 weight
percent of the total weight of the lubricating oil.
[0107] Low phosphorus engine oil formulations are included in this
disclosure. For such formulations, the phosphorus content is
typically less than about 0.12 weight percent preferably less than
about 0.10 weight percent and most preferably less than about 0.085
weight percent.
Dispersants
[0108] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
used in the formulation of the lubricating oil may be ashless or
ash-forming in nature. Preferably, the dispersant is ashless. So
called ashless dispersants are organic materials that form
substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0109] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorus. Typical hydrocarbon chains contain
50 to 400 carbon atoms.
[0110] A particularly useful class of dispersants are the
(poly)alkenylsuccinic derivatives, typically produced by the
reaction of a long chain hydrocarbyl substituted succinic compound,
usually a hydrocarbyl substituted succinic anhydride, with a
polyhydroxy or polyamino compound. The long chain hydrocarbyl group
constituting the oleophilic portion of the molecule which confers
solubility in the oil, is normally a polyisobutylene group. Many
examples of this type of dispersant are well known commercially and
in the literature. Exemplary U.S. patents describing such
dispersants are U.S. Pat. Nos. 3,172,892; 3,2145,707; 3,219,666;
3,316,177; 3,341,542; 3,444,170; 3,454,607; 3,541,012; 3,630,904;
3,632,511; 3,787,374 and 4,234,435. Other types of dispersant are
described in U.S. Pat. Nos. 3,036,003; 3,200,107; 3,254,025;
3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,413,347; 3,697,574;
3,725,277; 3,725,480; 3,726,882; 4,454,059; 3,329,658; 3,449,250;
3,519,565; 3,666,730; 3,687,849; 3,702,300; 4,100,082; 5,705,458. A
further description of dispersants may be found, for example, in
European Patent Application No. 471 071, to which reference is made
for this purpose.
[0111] Hydrocarbyl-substituted succinic acid and
hydrocarbyl-substituted succinic anhydride derivatives are useful
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0112] Succinimides are formed by the condensation reaction between
hydrocarbyl substituted succinic anhydrides and amines. Molar
ratios can vary depending on the polyamine. For example, the molar
ratio of hydrocarbyl substituted succinic anhydride to TEPA can
vary from about 1:1 to about 5:1. Representative examples are shown
in U.S. Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746;
3,322,670; and U.S. Pat. Nos. 3,652,616, 3,948,800; and Canada
Patent No. 1,094,044.
[0113] Succinate esters are formed by the condensation reaction
between hydrocarbyl substituted succinic anhydrides and alcohols or
polyols. Molar ratios can vary depending on the alcohol or polyol
used. For example, the condensation product of a hydrocarbyl
substituted succinic anhydride and pentaerythritol is a useful
dispersant.
[0114] Succinate ester amides are formed by condensation reaction
between hydrocarbyl substituted succinic anhydrides and alkanol
amines. For example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0115] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500 or more. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid. The above
products can also be post reacted with boron compounds such as
boric acid, borate esters or highly borated dispersants, to form
borated dispersants generally having from about 0.1 to about 5
moles of boron per mole of dispersant reaction product.
[0116] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, which is incorporated herein by reference. Process aids
and catalysts, such as oleic acid and sulfonic acids, can also be
part of the reaction mixture. Molecular weights of the alkylphenols
range from 800 to 2,500. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0117] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this disclosure can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HNR.sub.2 group-containing reactants.
[0118] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197.
[0119] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
about 500 to about 5000, or from about 1000 to about 3000, or about
1000 to about 2000, or a mixture of such hydrocarbylene groups,
often with high terminal vinylic groups. Other preferred
dispersants include succinic acid-esters and amides,
alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components.
[0120] Polymethacrylate or polyacrylate derivatives are another
class of dispersants. These dispersants are typically prepared by
reacting a nitrogen containing monomer and a methacrylic or acrylic
acid esters containing 5-25 carbon atoms in the ester group.
Representative examples are shown in U.S. Pat. Nos. 2,100,993, and
6,323,164. Polymethacrylate and polyacrylate dispersants are
normally used as multifunctional viscosity modifiers. The lower
molecular weight versions can be used as lubricant dispersants or
fuel detergents.
[0121] Illustrative preferred dispersants useful in this disclosure
include those derived from polyalkenyl-substituted mono- or
dicarboxylic acid, anhydride or ester, which dispersant has a
polyalkenyl moiety with a number average molecular weight of at
least 900 and from greater than 1.3 to 1.7, preferably from greater
than 1.3 to 1.6, most preferably from greater than 1.3 to 1.5,
functional groups (mono- or dicarboxylic acid producing moieties)
per polyalkenyl moiety (a medium functionality dispersant).
Functionality (F) can be determined according to the following
formula:
F=(SAP.times.M.sub.n)/((112,200.times.A.I.)-(SAP.times.98))
wherein SAP is the saponification number (i.e., the number of
milligrams of KOH consumed in the complete neutralization of the
acid groups in one gram of the succinic-containing reaction
product, as determined according to ASTM D94); M.sub.n is the
number average molecular weight of the starting olefin polymer; and
A.I. is the percent active ingredient of the succinic-containing
reaction product (the remainder being unreacted olefin polymer,
succinic anhydride and diluent).
[0122] The polyalkenyl moiety of the dispersant may have a number
average molecular weight of at least 900, suitably at least 1500,
preferably between 1800 and 3000, such as between 2000 and 2800,
more preferably from about 2100 to 2500, and most preferably from
about 2200 to about 2400. The molecular weight of a dispersant is
generally expressed in terms of the molecular weight of the
polyalkenyl moiety. This is because the precise molecular weight
range of the dispersant depends on numerous parameters including
the type of polymer used to derive the dispersant, the number of
functional groups, and the type of nucleophilic group employed.
[0123] Polymer molecular weight, specifically M.sub.n, can be
determined by various known techniques. One convenient method is
gel permeation chromatography (GPC), which additionally provides
molecular weight distribution information (see W. W. Yau, J. J.
Kirkland and D. D. Bly, "Modern Size Exclusion Liquid
Chromatography", John Wiley and Sons, New York, 1979). Another
useful method for determining molecular weight, particularly for
lower molecular weight polymers, is vapor pressure osmometry (e.g.,
ASTM D3592).
[0124] The polyalkenyl moiety in a dispersant preferably has a
narrow molecular weight distribution (MWD), also referred to as
polydispersity, as determined by the ratio of weight average
molecular weight (M.sub.w) to number average molecular weight
(M.sub.n). Polymers having a M.sub.w/M.sub.n of less than 2.2,
preferably less than 2.0, are most desirable. Suitable polymers
have a polydispersity of from about 1.5 to 2.1, preferably from
about 1.6 to about 1.8.
[0125] Suitable polyalkenes employed in the formation of the
dispersants include homopolymers, interpolymers or lower molecular
weight hydrocarbons. One family of such polymers comprise polymers
of ethylene and/or at least one C.sub.3 to C.sub.2 alpha-olefin
having the formula H.sub.2C.dbd.CHR.sup.1 wherein R.sup.1 is a
straight or branched chain alkyl radical comprising 1 to 26 carbon
atoms and wherein the polymer contains carbon-to-carbon
unsaturation, and a high degree of terminal ethenylidene
unsaturation. Preferably, such polymers comprise interpolymers of
ethylene and at least one alpha-olefin of the above formula,
wherein R.sup.1 is alkyl of from 1 to 18 carbon atoms, and more
preferably is alkyl of from 1 to 8 carbon atoms, and more
preferably still of from 1 to 2 carbon atoms.
[0126] Another useful class of polymers is polymers prepared by
cationic polymerization of monomers such as isobutene and styrene.
Common polymers from this class include polyisobutenes obtained by
polymerization of a C.sub.4 refinery stream having a butene content
of 35 to 75% by wt., and an isobutene content of 30 to 60% by wt. A
preferred source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feedstocks are disclosed in
the art such as in U.S. Pat. No. 4,952,739. A preferred embodiment
utilizes polyisobutylene prepared from a pure isobutylene stream or
a Raffinate I stream to prepare reactive isobutylene polymers with
terminal vinylidene olefins. Polyisobutene polymers that may be
employed are generally based on a polymer chain of from 1500 to
3000.
[0127] The dispersant(s) are preferably non-polymeric (e.g., mono-
or bis-succinimides). Such dispersants can be prepared by
conventional processes such as disclosed in U.S. Patent Application
Publication No. 2008/0020950, the disclosure of which is
incorporated herein by reference.
[0128] The dispersant(s) can be borated by conventional means, as
generally disclosed in U.S. Pat. Nos. 3,087,936, 3,254,025 and
5,430,105.
[0129] Such dispersants may be used in an amount of about 0.01 to
20 weight percent or 0.01 to 10 weight percent, preferably about
0.5 to 8 weight percent, or more preferably 0.5 to 4 weight
percent. Or such dispersants may be used in an amount of about 2 to
12 weight percent, preferably about 4 to 10 weight percent, or more
preferably 6 to 9 weight percent. On an active ingredient basis,
such additives may be used in an amount of about 0.06 to 14 weight
percent, preferably about 0.3 to 6 weight percent. The hydrocarbon
portion of the dispersant atoms can range from C.sub.60 to
C.sub.1000, or from C.sub.70 to C.sub.300, or from C.sub.70 to
C.sub.200. These dispersants may contain both neutral and basic
nitrogen, and mixtures of both. Dispersants can be end-capped by
borates and/or cyclic carbonates. Nitrogen content in the finished
oil can vary from about 200 ppm by weight to about 2000 ppm by
weight, preferably from about 200 ppm by weight to about 1200 ppm
by weight. Basic nitrogen can vary from about 100 ppm by weight to
about 1000 ppm by weight, preferably from about 100 ppm by weight
to about 600 ppm by weight.
[0130] As used herein, the dispersant concentrations are given on
an "as delivered" basis. Typically, the active dispersant is
delivered with a process oil. The "as delivered" dispersant
typically contains from about 20 weight percent to about 80 weight
percent, or from about 40 weight percent to about 60 weight
percent, of active dispersant in the "as delivered" dispersant
product.
Viscosity Modifiers
[0131] Viscosity modifiers (also known as viscosity index improvers
(VI improvers), and viscosity improvers) can be included in the
lubricant compositions of this disclosure.
[0132] Viscosity modifiers provide lubricants with high and low
temperature operability. These additives impart shear stability at
elevated temperatures and acceptable viscosity at low
temperatures.
[0133] Suitable viscosity modifiers include high molecular weight
hydrocarbons, polyesters and viscosity modifier dispersants that
function as both a viscosity modifier and a dispersant. Typical
molecular weights of these polymers are between about 10,000 to
1,500,000, more typically about 20,000 to 1,200,000, and even more
typically between about 50,000 and 1,000,000.
[0134] Examples of suitable viscosity modifiers are linear or
star-shaped polymers and copolymers of methacrylate, butadiene,
olefins, or alkylated styrenes. Polyisobutylene is a commonly used
viscosity modifier. Another suitable viscosity modifier is
polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity modifiers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
50,000 to 200,000 molecular weight.
[0135] Olefin copolymers are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921" and "PARATONE.RTM. 8941"); from Afton
Chemical Corporation under the trade designation "HiTEC.RTM." (such
as "HiTEC.RTM. 5850B"; and from The Lubrizol Corporation under the
trade designation "Lubrizol.RTM. 7067C". Hydrogenated polyisoprene
star polymers are commercially available from Infineum
International Limited, e.g., under the trade designation "SV200"
and "SV600". Hydrogenated diene-styrene block copolymers are
commercially available from Infineum International Limited, e.g.,
under the trade designation "SV 50".
[0136] The polymethacrylate or polyacrylate polymers can be linear
polymers which are available from Evnoik Industries under the trade
designation "Viscoplex.RTM." (e.g., Viscoplex 6-954) or star
polymers which are available from Lubrizol Corporation under the
trade designation Asteric.TM. (e.g., Lubrizol 87708 and Lubrizol
87725).
[0137] Illustrative vinyl aromatic-containing polymers useful in
this disclosure may be derived predominantly from vinyl aromatic
hydrocarbon monomer. Illustrative vinyl aromatic-containing
copolymers useful in this disclosure may be represented by the
following general formula:
A-B
wherein A is a polymeric block derived predominantly from vinyl
aromatic hydrocarbon monomer, and B is a polymeric block derived
predominantly from conjugated diene monomer.
[0138] In an embodiment of this disclosure, the viscosity modifiers
may be used in an amount of less than about 10 weight percent,
preferably less than about 7 weight percent, more preferably less
than about 4 weight percent, and in certain instances, may be used
at less than 2 weight percent, preferably less than about 1 weight
percent, and more preferably less than about 0.5 weight percent,
based on the total weight of the formulated oil or lubricating
engine oil. Viscosity modifiers are typically added as
concentrates, in large amounts of diluent oil.
[0139] As used herein, the viscosity modifier concentrations are
given on an "as delivered" basis. Typically, the active polymer is
delivered with a diluent oil. The "as delivered" viscosity modifier
typically contains from 20 weight percent to 75 weight percent of
an active polymer for polymethacrylate or polyacrylate polymers, or
from 8 weight percent to 20 weight percent of an active polymer for
olefin copolymers, hydrogenated polyisoprene star polymers, or
hydrogenated diene-styrene block copolymers, in the "as delivered"
polymer concentrate.
Antioxidants
[0140] Antioxidants retard the oxidative degradation of base oils
during service. Such degradation may result in deposits on metal
surfaces, the presence of sludge, or a viscosity increase in the
lubricant. One skilled in the art knows a wide variety of oxidation
inhibitors that are useful in lubricating oil compositions. See,
Klamann in Lubricants and Related Products, op cite, and U.S. Pat.
Nos. 4,798,684 and 5,084,197, for example.
[0141] Useful antioxidants include hindered phenols. These phenolic
antioxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones which contain a sterically hindered hydroxyl group, and
these include those derivatives of dihydroxy aryl compounds in
which the hydroxyl groups are in the o- or p-position to each
other. Typical phenolic antioxidants include the hindered phenols
substituted with C.sub.6+ alkyl groups and the alkylene coupled
derivatives of these hindered phenols. Examples of phenolic
materials of this type 2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl
phenol; 2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant disclosure. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2'-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0142] Effective amounts of one or more catalytic antioxidants may
also be used. The catalytic antioxidants comprise an effective
amount of a) one or more oil soluble polymetal organic compounds;
and, effective amounts of b) one or more substituted
N,N'-diaryl-o-phenylenediamine compounds or c) one or more hindered
phenol compounds; or a combination of both b) and c). Catalytic
antioxidants are more fully described in U.S. Pat. No. 8,048,833,
herein incorporated by reference in its entirety.
[0143] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R.sup.8R.sup.9R.sup.10N
where R.sup.8 is an aliphatic, aromatic or substituted aromatic
group, R.sup.9 is an aromatic or a substituted aromatic group, and
R.sup.10 is H, alkyl, aryl or R.sup.11S(O).sub.XR.sup.12 where
R.sup.11 is an alkylene, alkenylene, or aralkylene group, R.sup.12
is a higher alkyl group, or an alkenyl, aryl, or alkaryl group, and
x is 0, 1 or 2. The aliphatic group R.sup.8 may contain from 1 to
about 20 carbon atoms, and preferably contains from about 6 to 12
carbon atoms. The aliphatic group is a saturated aliphatic group.
Preferably, both R.sup.8 and R.sup.9 are aromatic or substituted
aromatic groups, and the aromatic group may be a fused ring
aromatic group such as naphthyl. Aromatic groups R.sup.8 and
R.sup.9 may be joined together with other groups such as S.
[0144] Typical aromatic amines antioxidants have alkyl substituent
groups of at least about 6 carbon atoms. Examples of aliphatic
groups include hexyl, heptyl, octyl, nonyl, and decyl. Generally,
the aliphatic groups will not contain more than about 14 carbon
atoms. The general types of amine antioxidants useful in the
present compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present disclosure
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0145] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0146] Preferred antioxidants include hindered phenols, arylamines.
These antioxidants may be used individually by type or in
combination with one another. Such additives may be used in an
amount of about 0.01 to 5 weight percent, preferably about 0.01 to
1.5 weight percent, more preferably zero to less than 1.5 weight
percent, more preferably zero to less than 1 weight percent.
Pour Point Depressants (PPDs)
[0147] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
disclosure if desired. These pour point depressant may be added to
lubricating compositions of the present disclosure to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Such additives may be
used in an amount of about 0.01 to 5 weight percent, preferably
about 0.01 to 1.5 weight percent.
Seal Compatibility Agents
[0148] Seal compatibility agents help to swell elastomeric seals by
causing a chemical reaction in the fluid or physical change in the
elastomer. Suitable seal compatibility agents for lubricating oils
include organic phosphates, aromatic esters, aromatic hydrocarbons,
esters (butylbenzyl phthalate, for example), and polybutenyl
succinic anhydride. Such additives may be used in an amount of
about 0.01 to 3 weight percent, preferably about 0.01 to 2 weight
percent.
Antifoam Agents
[0149] Anti-foam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical anti-foam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Anti-foam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 weight
percent and often less than 0.1 weight percent.
Inhibitors and Antirust Additives
[0150] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. A wide variety of these are
commercially available.
[0151] One type of antirust additive is a polar compound that wets
the metal surface preferentially, protecting it with a film of oil.
Another type of antirust additive absorbs water by incorporating it
in a water-in-oil emulsion so that only the oil touches the metal
surface. Yet another type of antirust additive chemically adheres
to the metal to produce a non-reactive surface. Examples of
suitable additives include zinc dithiophosphates, metal phenolates,
basic metal sulfonates, fatty acids and amines. Such additives may
be used in an amount of about 0.01 to 5 weight percent, preferably
about 0.01 to 1.5 weight percent.
Friction Modifiers
[0152] A friction modifier is any material or materials that can
alter the coefficient of friction of a surface lubricated by any
lubricant or fluid containing such material(s). Friction modifiers,
also known as friction reducers, or lubricity agents or oiliness
agents, and other such agents that change the ability of base oils,
formulated lubricant compositions, or functional fluids, to modify
the coefficient of friction of a lubricated surface may be
effectively used in combination with the base oils or lubricant
compositions of the present disclosure if desired. Friction
modifiers that lower the coefficient of friction are particularly
advantageous in combination with the base oils and lube
compositions of this disclosure.
[0153] Illustrative friction modifiers may include, for example,
organometallic compounds or materials, or mixtures thereof.
Illustrative organometallic friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, molybdenum amine, molybdenum diamine, an
organotungstenate, a molybdenum dithiocarbamate, molybdenum
dithiophosphates, molybdenum amine complexes, molybdenum
carboxylates, and the like, and mixtures thereof. Similar tungsten
based compounds may be preferable.
[0154] Other illustrative friction modifiers useful in the
lubricating engine oil formulations of this disclosure include, for
example, alkoxylated fatty acid esters, alkanolamides, polyol fatty
acid esters, borated glycerol fatty acid esters, fatty alcohol
ethers, and mixtures thereof.
[0155] Illustrative alkoxylated fatty acid esters include, for
example, polyoxyethylene stearate, fatty acid polyglycol ester, and
the like. These can include polyoxypropylene stearate,
polyoxybutylene stearate, polyoxyethylene isosterate,
polyoxypropylene isostearate, polyoxyethylene palmitate, and the
like.
[0156] Illustrative alkanolamides include, for example, lauric acid
diethylalkanolamide, palmic acid diethylalkanolamide, and the like.
These can include oleic acid diethyalkanolamide, stearic acid
diethylalkanolamide, oleic acid diethylalkanolamide,
polyethoxylated hydrocarbylamides, polypropoxylated
hydrocarbylamides, and the like.
[0157] Illustrative polyol fatty acid esters include, for example,
glycerol mono-oleate, saturated mono-, di-, and tri-glyceride
esters, glycerol mono-stearate, and the like. These can include
polyol esters, hydroxyl-containing polyol esters, and the like.
[0158] Illustrative borated glycerol fatty acid esters include, for
example, borated glycerol mono-oleate, borated saturated mono-,
di-, and tri-glyceride esters, borated glycerol mono-sterate, and
the like. In addition to glycerol polyols, these can include
trimethylolpropane, pentaerythritol, sorbitan, and the like. These
esters can be polyol monocarboxylate esters, polyol dicarboxylate
esters, and on occasion polyoltricarboxylate esters. Preferred can
be the glycerol mono-oleates, glycerol dioleates, glycerol
trioleates, glycerol monostearates, glycerol distearates, and
glycerol tristearates and the corresponding glycerol
monopalmitates, glycerol dipalmitates, and glycerol tripalmitates,
and the respective isostearates, linoleates, and the like. On
occasion the glycerol esters can be preferred as well as mixtures
containing any of these. Ethoxylated, propoxylated, butoxylated
fatty acid esters of polyols, especially using glycerol as
underlying polyol can be preferred.
[0159] Illustrative fatty alcohol ethers include, for example,
stearyl ether, myristyl ether, and the like. Alcohols, including
those that have carbon numbers from C.sub.3 to C.sub.50, can be
ethoxylated, propoxylated, or butoxylated to form the corresponding
fatty alkyl ethers. The underlying alcohol portion can preferably
be stearyl, myristyl, C.sub.11-C.sub.13 hydrocarbon, oleyl,
isosteryl, and the like.
[0160] The lubricating oils of this disclosure exhibit desired
properties, e.g., wear control, in the presence or absence of a
friction modifier.
[0161] Useful concentrations of friction modifiers may range from
0.01 weight percent to 5 weight percent, or about 0.1 weight
percent to about 2.5 weight percent, or about 0.1 weight percent to
about 1.5 weight percent, or about 0.1 weight percent to about 1
weight percent. Concentrations of molybdenum-containing materials
are often described in terms of Mo metal concentration.
Advantageous concentrations of Mo may range from 25 ppm to 700 ppm
or more, and often with a preferred range of 50-200 ppm. Friction
modifiers of all types may be used alone or in mixtures with the
materials of this disclosure. Often mixtures of two or more
friction modifiers, or mixtures of friction modifier(s) with
alternate surface active material(s), are also desirable.
[0162] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 1 below.
[0163] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating oil composition.
TABLE-US-00002 TABLE 1 Typical Amounts of Other Lubricating Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Dispersant 0.1-20 0.1-8 Detergent 0.1-20 0.1-8 Friction
Modifier 0.01-5 0.01-1.5 Antioxidant 0.1-5 0.1-1.5 Pour Point
Depressant (PPD) 0.0-5 0.01-1.5 Anti-foam Agent 0.001-3 0.001-0.15
Viscosity Modifier 0.1-2 0.1-1 (solid polymer basis) Antiwear 0.2-3
0.5-1 Inhibitor and Antirust 0.01-5 0.01-1.5
[0164] The foregoing additives are all commercially available
materials. These additives may be added independently but are
usually precombined in packages which can be obtained from
suppliers of lubricant oil additives. Additive packages with a
variety of ingredients, proportions and characteristics are
available and selection of the appropriate package will take the
requisite use of the ultimate composition into account.
[0165] The following non-limiting examples are provided to
illustrate the disclosure.
EXAMPLES
[0166] Formulations were prepared as described herein. All of the
ingredients used herein are commercially available. Passenger
vehicle engine oil (PVEO) formulations were prepared as described
herein.
[0167] The antiwear additives used in the formulations were zinc
stearate, tin stearate, sodium stearate, aluminum stearate,
magnesium stearate, calcium stearate, silver stearate, palladium
stearate, zinc undecylenate, zinc oleate, and zinc napthenate.
[0168] The detergents used in the formulations were calcium
salicylate and magnesium sulfonate.
[0169] The additive package used in the formulations included
conventional additives in conventional amounts. Conventional
additives used in the formulations were one or more of an
antioxidant, dispersant, pour point depressant, detergent,
corrosion inhibitor, metal deactivator, seal compatibility
additive, anti-foam agent, inhibitor, anti-rust additive, and
friction modifier.
[0170] A tribometer was used for measuring wear. A ball was held in
a reciprocating arm so that it was brought into contact with a flat
disk. The flat disk and the ball were positioned inside a lubricant
reservoir and sufficient lubricant is placed in the reservoir to
cover the contact point between ball and disk. The reciprocating
arm was reciprocated back and forth while maintaining contact
between the ball and disk. A variable weight was hung over the
reciprocating arm thus allowing wear to be measured under different
load conditions. In addition, the stroke length of the
reciprocating arm can be varied as was the oil reservoir
temperature. Friction was measured with a load cell attached to the
reciprocating arm.
[0171] Wear performance was evaluated as described above using a
High Frequency Reciprocating Rig (HFRR) test. The HFRR is
commercially available from PCS Industries. The test equipment and
procedure are similar to the ASTM D6079 method. The HFRR test
conditions were as follows: temperature 100.degree. C.; test
duration 2 hours; stroke length 1 mm; frequency 10 Hz; and load 400
grams. Wear was measured only on the disc. The ball is 6 mm
diameter ANSI E-52100 steel, Rockwell C hardness of 58-66. The disc
is AISI E-52100 steel, Vickers HV30 hardness of .about.200.
[0172] The lubricant formulations used in the Examples are shown in
Table 2 below. The weight percent (wt %) indicated below is based
on the total weight of the lubricating oil composition.
TABLE-US-00003 TABLE 2 Lubricant Component Partial Formulation Full
Formulation Description (wt %) (wt %) Synthetic Base Oil Mixture
82.5-91.5 80.5-89.5 Viscosity Modifier 0-5 0-5 Performance
Additives System 9-10 9-10 ZDDP & Friction Modifiers 0 2
Additive of this Disclosure .sup. 0-1.5 0
Example 1
[0173] Zinc stearate was blended into polyalphaolefin (PAO 4) and
tested in the HFRR. This wear test run was compared to a wear test
run on PAO 4 containing no additives. During the two hour duration
of the HFRR test a continuous measurement of friction between the
ball and flat cylinder was made. While friction changed during the
duration of the test, the friction measurement used herein was the
average friction during the last half hour of the test procedure.
This number is referred to as the average friction. After the HFRR
test was completed, the ball and disk were removed from the
tribometer. The topography (i.e., depth profile) of the wear scar
produced at the center of the disk was measured with a
profilimeter. The depth of the elongated wear scar was measured
along three lines across the wear scar. One profile was generated
across the center of the wear scar, a second and third were
measured to the right and left of the wear scar center line. A
single wear scar depth number was generated by taking the average
depth achieved at the center of each of the three profiles and
averaging them.
[0174] The wear scar depth for the zinc stearate containing fluid
is tabulated below (Run 2) and compared to the wear scar depth for
the PAO test (Run 1). The data shows that zinc stearate reduced
wear and friction when added to the lubricant base stock. It should
be noted that when zinc stearate is tested on its own in PAO
basestock, due to the low solubility of zn stearate, the result can
be variable and will depend on time between blending and time of
evaluation.
TABLE-US-00004 Wear Scar Test Antiwear Concentration Depth Average
Number Additive (weight %) (Angstroms) Friction 1 None -- 70000
0.53 80000 0.43 2 Zinc Stearate 1.5 26000 0.10
Example 2
[0175] Zinc stearate was tested in the HFRR in a lubricant blend
containing a mixture of detergent salts. The detergent salt mixture
contained both calcium salicylate and magnesium sulfonate. The
calcium salicylate is a mixture of low, medium and high TBN
salicylates. PAO 4 was used as the base stock. PAO 4 is a non-polar
paraffinic base stock. Profiles of the wear scar were generated as
described above and the wear scar depth is tabulated below.
TABLE-US-00005 Wear Scar Test Antiwear Concentration Concentration
Depth Average Number Additive (weight %) Additive (weight %)
(Angstroms) Friction 3 Zinc 1.5% Detergents 2-3% 4500 0.09
Stearate
[0176] A comparison of Run 3 containing zinc stearate and
detergents to Runs 2 (zinc stearate alone) and Run 1 (PAO alone)
demonstrates that there is a beneficial reduction in wear and
beneficial reduction in friction resulting from the combination of
zinc stearate and detergent (i.e., calcium salicylate and magnesium
sulfonate).
Example 3
[0177] Zinc stearate was tested in a partially formulated engine
oil containing a full detergent and dispersant package of additives
(but not containing a friction modifier or ZDDP) and tested in the
HFRR (Run 4). A test was also run on the partial lubricant
containing the detergent and dispersant package alone (Run 5). Wear
scars were profiled as described above and the wear scar depths are
tabulated below. The data demonstrate that even when blended into a
full detergent and dispersant package with other additives
typically used in lubricants, but not containing a friction
modifier or ZDDP, the addition of zinc stearate reduces wear and
friction. The detergent concentration of the partial formulation
was between 2-3% by weight containing a mixture of calcium
salicylates and magnesium sulfonate.
TABLE-US-00006 Wear Scar Test Antiwear Concentration Depth Average
Number Additive (weight %) (Angstroms) Friction 4 Zn Stearate 1.5%
4500 0.08 5 None -- 36000 0.15
Example 4
[0178] HFRR tests were run to compare the antiwear performance of
zinc stearate with other metal stearates. In this series of tests,
each stearate was blended into the partial lubricant formulation
containing a fully formulated engine oil detergent and dispersant
additive formulation (not containing a friction modifier or ZDDP).
Each lubricant and one of the stearates were evaluated in the HFRR
test and the wear scars were evaluated as described above. Wear
scar depths are tabulated below. In some cases, data represents
averages of several experiments.
TABLE-US-00007 Wear Scar Test Antiwear Concentration Depth Average
Number Additive (weight %) (Angstroms) Friction 4 Zinc Stearate
1.5% 4500 0.08 5 None -- 36000 0.15 6 Silver Stearate 0.62% 4000
0.08 7 Palladium 1.06% 4000 0.08 Stearate 8 Tin Stearate 1.5% 7000
0.09 9 Sodium Stearate 1.5% 15000 0.10 10 Aluminum 1.5% 17000 0.14
Stearate 11 Magnesium 1.5% 22500 0.18 Stearate 12 Calcium Stearate
1.5% 23000 0.17
[0179] The data shows that zinc stearate had the best wear and
friction performance. The data also shows that other stearates
reduced wear and friction to differing levels of effectiveness.
Example 5
[0180] Different zinc carboxylate salts were tested in the HFRR.
These represent salts of zinc and different carboxylate anions. The
testing results are tabulated in FIG. 3.
[0181] The data in FIG. 3 demonstrates that straight chain
carboxylates have better performance than non-straight chains as
indicated by runs 4 (zinc stearate), 13 (zinc undecylenate) and 14
(zinc oleate) compared with run 15 (zinc napthenate) which is not a
straight chain. Better performance was achieved with the stearate
which is a saturated straight chain of 18 carbons.
[0182] Engine testing was also conducted for formulations of this
disclosure. The engine testing included measurements of the
following parameters: IIIG kinematic viscosity increase at
40.degree. C. (%) as measured by ASTM D7320 (lower value is
better); IIIG average weighted piston deposits (merits) as measured
by ASTM D7320 (higher value is better); IIIG average cam and lifter
wear (.mu.m) as measured by ASTM D7320 (lower value is better);
IIIG average piston skirt varnish (merits) as measured by ASTM
D7320 (higher value is better); IIIG oil ring land deposit (merits)
as measured by ASTM D7320 (higher value is better); IIIG undercrown
(merits) as measured by ASTM D7320 (higher value is better); IIIG
groove 1 as measured by ASTM D7320 (higher value is better); IIIG
groove 2 as measured by ASTM D7320 (higher value is better); IIIG
groove 3 as measured by ASTM D7320 (higher value is better); and
IIIG land 2 as measured by ASTM D7320 (higher value is better).
Example 6
[0183] The lubricants used in HFRR run 4 and run 5 were tested in a
sequence IIIG engine test as described above. The results of
sequence IIIG engine testing are tabulated below. The results
demonstrate that the addition of zinc stearate to the lubricant
reduced wear, reduced engine deposits and improved the oxidative
stability of the lubricant.
TABLE-US-00008 Oil From Run 4 (Contains Zn Stearate) Oil From Run 5
Average Piston Skirt Varnish 9.79 9.40 Weighted Piston Deposit 6.92
4.15 Cam & Lifter Wear (microns) 35.1 343.8 Viscosity Increase
(percent) 44.1 246 Oil Ring Land Deposit 8.11 4.27 (merit rating)
Piston Undercrown Deposit 8.63 3.27 (merit rating) Piston Groove 1
(merit rating) 1.91 1.46 Piston Groove 2 (merit rating) 3.50 1.01
Piston Groove 3 (merit rating) 9.51 6.33 Piston Land 2 (merit
rating) 1.97 1.08 Merit ratings: 0-10 (10 = Clean)
[0184] Antiwear performance is indicated by the low cam and lifter
wear result achieved for the Run 4 oil containing zinc stearate.
Improved oxidation control is indicated by the low viscosity
increase. Oxidation is a significant contributor to oil thickening
and viscosity increase. Improved engine deposit control is
indicated by the high merit ratings achieved for various piston
deposits. Higher merit ratings indicate lower deposits and cleaner
pistons.
[0185] FIGS. 1-3 depict results from testing carried out in
Examples 1-6.
[0186] FIG. 1 (top) shows the performance in one experiment of the
partial formulation in which ZDDP and friction modifiers were
removed ("partial" formulation). FIG. 1 (bottom) shows performance
in one experiment for the full formulation. FIG. 1 (top and bottom)
contain three lines. Each line is a depth profile of the final wear
scar across the center, right and left of the oval shaped scar. The
absence of ZDDP results in a deeper scar.
[0187] FIG. 2 shows the wear scar data generated when zinc stearate
was added to the "partial" formulation. The three lines represent
depth profiles of the final wear scar in the center, right and left
of the scar. The depth of this wear scar is less than the full
formulation shown in FIG. 1.
[0188] FIG. 3 shows the results of HFRR testing for other metal
carboxylate salts in addition to zinc stearate in FIG. 2. Some
results are averages over several experiments.
Example 7
[0189] Lubricating oils were blended with varying concentrations of
zinc stearate and salicylate detergents (Ca and Mg with component
Total Base Numbers of 70, 342 and 350) to form inventive
lubricating oils. The base stock used for all the inventive and
comparative blends included 95 wt % PAO-4 and 5 wt % of alkylated
naphthalene. The lubricating oils were also blended with varying
concentrations of zinc stearate and sulfonate detergents (Ca and Mg
with component Total Base Numbers of 8, 300 and 400) to form
comparative lubricating oils. The comparative and inventive
lubricating oils did not include any other lubricating oil
additives. The comparative and inventive lubricating oils were
tested for average friction and average wear using the HFRR method
described above. FIG. 4 is a plot of average friction versus the
ratio of moles of detergent metal (Ca, Mg) divided by the total
moles of zinc from zinc stearate for both salicylate detergents
(inventive) and sulfonate detergents (comparative). FIG. 5 is a
plot of average wear versus the ratio of moles of detergent metal
(Ca, Mg) divided by the total moles of zinc from zinc stearate for
both salicylate detergents (inventive) and sulfonate detergents
(comparative). The results in FIG. 4 indicate that there was a
synergy for both Ca salicylate and Mg salicylate detergents for
improving average friction when used in combination with zinc
stearate. At a Ca/Zn ratio of 0.37 and higher there was a friction
synergy. We are comparing to a reference point of basestock alone
where friction is 0.16 (zero on the x-axis). The results in FIG. 5
also indicate that there was a synergy for the Ca salicylate
detergent for improving average wear when used in combination with
zinc stearate.
[0190] While not wishing to be bound to any particular theory, it
is believed that the antiwear performance of the formulations of
this disclosure is unexpectedly enhanced by an interaction between
zinc stearate and other molecules in the additive formulation. One
example of this is the interaction of antiwear with the detergents
(i.e., salicylate).
[0191] The lubricants of this disclosure are low in sulfur and are
less corrosive toward iron than antiwear additives containing
sulfur. One manifestation of this is that the present disclosure is
less likely to corrode ferrous materials (e.g., steel) to produce
iron sulfide.
PCT and EP Clauses:
[0192] 1. A method for improving wear control, while maintaining or
improving fuel efficiency, in an engine or other mechanical
component lubricated with a lubricating oil by using as the
lubricating oil a formulated oil, said formulated oil having a
composition comprising a lubricating oil base stock as a major
component; and a mixture as a minor component of (i) at least one
metal salt of a straight chain carboxylic acid, wherein the metal
is selected from the group consisting of palladium (Pd), silver
(Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at
least one metal salicylate salt, wherein the metal is calcium (Ca),
magnesium (Mg) or combinations thereof; wherein the molar ratio of
the total metal concentration from the salicylate salt divided by
the total metal concentration from the straight chain carboxylic
acid ranges from 0.1 to 40; and wherein wear control is improved
and fuel efficiency is maintained or improved as compared to wear
control and fuel efficiency achieved using a lubricating oil
containing a minor component other than the mixture of the at least
one metal salt of a straight chain carboxylic acid and the at least
one metal salicylate salt.
[0193] 2. The method of clause 1 wherein the lubricating oil base
stock comprises a Group I, Group II, Group III, Group IV or Group V
base oil.
[0194] 3. The method of clauses 1-2 wherein the straight chain
carboxylic acid is an aliphatic, saturated, unbranched carboxylic
acid having from 8 to 26 carbon atoms, and mixtures thereof.
[0195] 4. The method of clauses 1-3 wherein the at least one metal
salt of the straight chain carboxylic acid comprises zinc stearate,
silver stearate, palladium stearate, zinc palmitate, silver
palmitate, palladium palmitate, or mixtures thereof.
[0196] 5. The method of clauses 1-4 wherein the at least one metal
salt of the straight chain carboxylic acid is present in an amount
of from 0.01 weight percent to 5 weight percent, based on the total
weight of the formulated oil.
[0197] 6. The method of clauses 1-5 wherein the at least one metal
salicylate salt is present in an amount of from 0.01 weight percent
to 5 weight percent, based on the total weight of the formulated
oil.
[0198] 7. The method of clauses 1-6 wherein the lubricating oil
base stock is present in an amount of from 70 weight percent to 95
weight percent, based on the total weight of the formulated
oil.
[0199] 8. The method of clauses 1-7 wherein the formulated oil
further comprises one or more of an antiwear additive, viscosity
modifier, antioxidant, detergent, other dispersant, pour point
depressant, corrosion inhibitor, metal deactivator, seal
compatibility additive, anti-foam agent, inhibitor, and anti-rust
additive.
[0200] 9. A lubricating oil having a composition comprising a
lubricating oil base stock as a major component; and a mixture as a
minor component of (i) at least one metal salt of a straight chain
carboxylic acid, wherein the metal is selected from the group
consisting of palladium (Pd), silver (Ag), gold (Au), zinc (Zn),
and combinations thereof, and (ii) at least one metal salicylate
salt, wherein the metal is calcium (Ca), magnesium (Mg) or
combinations thereof; wherein the molar ratio of the total metal
concentration from the salicylate salt divided by the total metal
concentration from the straight chain carboxylic acid ranges from
0.1 to 40; and wherein wear control is improved and fuel efficiency
is maintained or improved as compared to wear control and fuel
efficiency achieved using a lubricating oil containing a minor
component other than the mixture of the at least one metal salt of
a straight chain carboxylic acid and the at least one metal
salicylate salt.
[0201] 10. The lubricating oil of clause 9 wherein the lubricating
oil base stock comprises a Group I, Group II, Group III, Group IV
or Group V base oil.
[0202] 11. The lubricating oil of clauses 9-10 wherein the straight
chain carboxylic acid is an aliphatic, saturated, unbranched
carboxylic acid having from 8 to 26 carbon atoms, and mixtures
thereof.
[0203] 12. The lubricating oil of clauses 9-11 wherein the at least
one metal salt of the straight chain carboxylic acid comprises zinc
stearate, silver stearate, palladium stearate, zinc palmitate,
silver palmitate, palladium palmitate, or mixtures thereof.
[0204] 13. The lubricating oil of clauses 9-12 wherein the at least
one metal salt of the straight chain carboxylic acid is present in
an amount of from 0.01 weight percent to 5 weight percent, based on
the total weight of the formulated oil.
[0205] 14. The lubricating oil of clauses 9-13 wherein the at least
one metal salicylate salt is present in an amount of from 0.01
weight percent to 5 weight percent, based on the total weight of
the formulated oil.
[0206] 15. The lubricating oil of clauses 9-14 wherein the
lubricating oil base stock is present in an amount of from 70
weight percent to 95 weight percent, based on the total weight of
the formulated oil.
[0207] 16. The lubricating oil of clauses 9-15 wherein the
formulated oil further comprises one or more of an antiwear
additive, viscosity modifier, antioxidant, detergent, other
dispersant, pour point depressant, corrosion inhibitor, metal
deactivator, seal compatibility additive, anti-foam agent,
inhibitor, and anti-rust additive.
[0208] 17. The lubricating oil of clauses 9-16 which is a passenger
vehicle engine oil (PVEO).
[0209] All patents and patent applications, test procedures (such
as ASTM methods, UL methods, and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this disclosure and for all
jurisdictions in which such incorporation is permitted.
[0210] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0211] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *
References