U.S. patent application number 16/568811 was filed with the patent office on 2020-04-02 for low viscosity lubricating oils with improved oxidative stability and traction performance.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Mark P. Hagemeister, Halou Oumar-Mahamat, Candice I. Pelligra.
Application Number | 20200102519 16/568811 |
Document ID | / |
Family ID | 68069876 |
Filed Date | 2020-04-02 |
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United States Patent
Application |
20200102519 |
Kind Code |
A1 |
Oumar-Mahamat; Halou ; et
al. |
April 2, 2020 |
LOW VISCOSITY LUBRICATING OILS WITH IMPROVED OXIDATIVE STABILITY
AND TRACTION PERFORMANCE
Abstract
Provided is lubricating oil composition including from 10 to 90
wt % of a base stock comprising a C28-C32 hydrocarbon fraction
("dimers") and optionally a C42-C48 hydrocarbon fraction
("trimers") produced by oligomerization of a linear C14
mono-olefin, a linear C16 mono-olefin, or a mixture thereof, in the
presence of a Lewis acid catalyst, and the remainder of the
composition including one or more lubricating oil additives. The
lubricating oil composition provides an oxidative stability of
greater than 100 hours (time to 200% KV@40 deg. C. increase) and a
mini traction machine (MTM) average traction coefficient at 100
deg. C. of less than 0.0081.
Inventors: |
Oumar-Mahamat; Halou;
(Mullica Hill, NJ) ; Hagemeister; Mark P.; (Morris
Plains, NJ) ; Pelligra; Candice I.; (Rutledge,
PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
68069876 |
Appl. No.: |
16/568811 |
Filed: |
September 12, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62737197 |
Sep 27, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 2205/0285 20130101;
C10M 105/04 20130101; C10M 2203/024 20130101; C10N 2030/02
20130101; C10N 2040/25 20130101; C10N 2040/252 20200501; C10M
169/04 20130101; C10N 2030/06 20130101; C10N 2030/10 20130101; C10N
2020/02 20130101; C10N 2020/067 20200501 |
International
Class: |
C10M 105/04 20060101
C10M105/04 |
Claims
1. A lubricating oil composition comprising from 10 to 90 wt % of a
base stock comprising a C28-C32 hydrocarbon fraction ("dimers") and
optionally a C42-C48 hydrocarbon fraction ("trimers") produced by
oligomerization of a linear C14 mono-olefin, a linear C16
mono-olefin, or a mixture thereof, in the presence of a Lewis acid
catalyst, and the remainder of the composition comprising one or
more lubricating oil additives, wherein the lubricating oil
composition provides an oxidative stability of greater than 100
hours (time to 200% KV@40 deg. C. increase) and a mini traction
machine (MTM) average traction coefficient at 100 deg. C. of less
than 0.0081.
2. The composition of claim 1, wherein the base stock exhibits a
mole percentage of epsilon-carbons as determined by .sup.13C NMR of
no less than 20 mol %, based on the total moles of the carbon atoms
therein.
3. The composition of claim 1, wherein the dimers are at a
concentration in the range from 80 to 100 wt %, and the trimers are
at a concentration in the range from 0 to 20 wt %, based on the
total weight of the base stock.
4. The composition of claim 1, wherein the total concentration of
the dimers and the trimers combined is at least 95 wt %, based on
the total weight of the base stock.
5. The composition of claim 1, wherein the molecules of the dimers
comprise, on average, no more than 2.0 branches attached to the
carbon backbones therein.
6. The composition of claim 1, wherein the base stock has a pour
point as determined pursuant to ASTM D5950 of in a range from -45
to -10.degree. C.
7. The composition of claim 1, wherein the base stock has a
cold-crank-simulator viscosity as determined pursuant to ASTM D5293
("CCSV") at -35.degree. C. of at least 500 mPas.
8. The composition of claim 1, wherein the base stock has a
kinematic viscosity at 100.degree. C. as determined pursuant to
ASTM D445 ("KV100") in the range from 3.3 to 4.6 cSt.
9. The composition of claim 1, wherein the base stock has a CCSV at
-35.degree. C. of CCSVmPas; when blended with a PAO reference base
stock made from one or more linear alpha-olefin monomer(s)
comprising 8 to 12 carbon atoms having a KV100 of 4.0 to 4.2 cSt, a
pour point of no higher than -50.degree. C., a CCSV at -35.degree.
C. of CCSV(PAO4) mPas, where 1200.ltoreq.CCSV(PAO4).ltoreq.1500, to
form a first mixture oil comprising 10 wt % of the base stock based
on the total weight of the first mixture oil, a second mixture oil
comprising 20 wt % of the base stock based on the second mixture
oil, and a third mixture oil comprising 30 wt % of the base stock
based on the total weight of the base stock, at least one of the
following is met: (i) the first mixture oil exhibits a lower CCSV
at -35.degree. C. than the PAO reference base stock; (ii) the
second mixture oil exhibits a lower CCSV at -35.degree. C. than the
PAO reference base stock; and (iii) the third mixture oil exhibits
a lower CCSV at -35.degree. C. than the PAO reference base
stock.
10. The composition of claim 9, wherein the base stock meets at
least one of the following: (i) the first mixture oil exhibits a
CCSV at -35.degree. C. at least 50 mPas lower than that of the PAO
reference base stock; (ii) the second mixture oil exhibits a CCSV
at -35.degree. C. at least 50 mPas lower than that of the PAO
reference base stock; and (iii) the third mixture oil exhibits a
CCSV at -35.degree. C. at least 50 mPas lower than that of the PAO
reference base stock.
11. The composition of claim 9, wherein the base stock exhibits a
CCSV at -35.degree. C. lower than that of the PAO reference base
stock.
12. The composition of claim 1, wherein the one or more lubricating
oil additives are selected from the group consisting of a
detergent, dispersant, viscosity index improver, viscosity
modifier, metal passivator, antioxidant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, anti-foam agent, anti-rust additive, friction modifier,
extreme pressure agent and combinations thereof.
13. The composition of claim 12, wherein the one or more
lubricating oil additives comprise from 1 to 30 wt. % of the
lubricating oil composition.
14. The composition of claim 1 further including a cobase stock at
from 1 to 30 wt. % of the lubricating oil composition, wherein the
cobase stock is selected from the group consisting of a Group I
base stock, a Group II base stock, a Group III base stock, a
conventional Group IV base stock, a Group V base stock and
combinations thereof.
15. The composition of claim 1, wherein the lubricating oil
composition has a kinematic viscosity at 25.degree. C. as
determined pursuant to ASTM D445 ("KV25") at least 0.5% lower than
a comparable lubricating oil composition not including the C28-C32
hydrocarbon fraction ("dimers").
16. The composition of claim 1, wherein the lubricating oil
composition has a cold-crank-simulator viscosity as determined
pursuant to ASTM D5293 ("CCSV") at -35.degree. C. at least 5% lower
than a comparable lubricating oil composition not including the
C28-C32 hydrocarbon fraction ("dimers").
17. The composition of claim 1, wherein the lubricating oil
composition is used as a passenger vehicle engine oil (PVEO),
commercial vehicle engine oil (CVEO) or a natural gas engine
oil.
18. The composition of claim 1, wherein the lubricating oil
composition is an SAE viscosity grade selected from the group
consisting of 0W-30, 5W-30, 0W-20, 5W-20, 0W-16, 5W-16, 0W-12,
5W-12, 0W-8, and 5W-8.
19. A lubricating oil composition comprising: from 10 to 90 wt % of
a base stock comprising a C28 to C32 hydrocarbon first fraction at
a concentration in the range from 80 to 100 wt %, and a C42 to C48
second fraction at a concentration in the range from 0 to 20 wt %,
based on the total weight of the base stock; wherein the base stock
has a kinematic viscosity at 100.degree. C. as determined pursuant
to ASTM D445 ("KV100") in the range from 3.3 to 4.6 cSt; a pour
point as determined pursuant to ASTM D5950 in the range from -45 to
-10.degree. C.; and a cold-crank-simulator viscosity as determined
pursuant to ASTM D5293 ("CCSV") at -35.degree. C. of at least 500
mPas; and the remainder of the composition comprising one or more
lubricating oil additives, wherein the lubricating oil composition
provides an oxidative stability of greater than 100 hours (time to
200% KV@40 deg. C. increase) and a mini traction machine (MTM)
average traction coefficient at 100 deg. C. of less than
0.0081.
20. The composition of claim 19, further including a cobase stock
at from 1 to 30 wt. % of the lubricating oil composition, wherein
the cobase stock is selected from the group consisting of a Group I
base stock, a Group II base stock, a Group III base stock, a
conventional Group IV base stock, a Group V base stock and
combinations thereof.
21. The composition of claim 19 further including a Group II, III,
or IV base stock as a second base stock, wherein the first base
stock has a CCSV at -35.degree. C. of CCSV(1), the second base
stock has a CCSV at -35.degree. C. of CCSV(2), and the binary
mixture of the first base stock and the second base stock in the
oil composition absent any component other than the first base
stock and the second base stock has a CCSV at -35.degree. C. of
CCSV(3), such that: CCSV(2)>CCSV(3).
22. The composition of claim 21, wherein:
(CCSV(2)-CCSV(3))/CCSV(2).gtoreq.0.05.
23. The composition of claim 22, wherein: the second base stock
comprises a Group II or Group III base stock, and
(CCSV(2)-CCSV(3))/CCSV(2).gtoreq.0.10.
24. The composition of 23, wherein: CCSV(1).gtoreq.CCSV(2).
25. The composition of claim 19, wherein the one or more
lubricating oil additives are selected from the group consisting of
a detergent, dispersant, viscosity index improver, viscosity
modifier, metal passivator, antioxidant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, anti-foam agent, anti-rust additive, friction modifier,
extreme pressure agent and combinations thereof.
26. The composition of claim 25, wherein the one or more
lubricating oil additives comprise from 1 to 30 wt. % of the
lubricating oil composition.
27. The composition of claim 19, wherein the lubricating oil
composition has a kinematic viscosity at 25.degree. C. as
determined pursuant to ASTM D445 ("KV25") at least 0.5% lower than
a comparable lubricating oil composition not including the C28-C32
hydrocarbon fraction ("dimers").
28. The composition of claim 19, wherein the lubricating oil
composition has a cold-crank-simulator viscosity as determined
pursuant to ASTM D5293 ("CCSV") at -35.degree. C. at least 5% lower
than a comparable lubricating oil composition not including the
C28-C32 hydrocarbon fraction ("dimers").
29. The composition of claim 19, wherein the lubricating oil
composition is used as a passenger vehicle engine oil (PVEO),
commercial vehicle engine oil (CVEO) or a natural gas engine
oil.
30. The composition of claim 19, wherein the lubricating oil
composition is an SAE viscosity grade selected from the group
consisting of 0W-30, 5W-30, 0W-20, 5W-20, 0W-16, 5W-16, 0W-12,
5W-12, 0W-8, and 5W-8.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/737,197, filed on 27 Sep. 2018, the entire
contents of which are incorporated herein by reference.
FIELD
[0002] This disclosure relates to ultra-low viscosity and low
volatility lubricating oil compositions having outstanding
oxidative stability and traction performance. More particularly,
the ultra-low viscosity and low volatility lubricating oil
compositions incorporate a base stock comprising a C28-C32
hydrocarbon fraction ("dimers") and optionally a C42-C48
hydrocarbon fraction ("trimers"). The lubricating oil compositions
are particularly useful for formulating 0W grades engine oils.
BACKGROUND
[0003] Modern regulations are forcing auto builders to address new
daunting CO.sub.2 emission and fuel economy (FE) requirements which
are escalating rapidly on a global scale. To meet these
requirements, new engine and lubrication technologies are needed.
Among the array of new technologies that are being progressed is
the use of ultra-low viscosity lubricants to gain energy efficiency
in engine applications. The development of ultra-low viscosity
synthetic base stocks having controlled volatility would enable
finished ultra-low viscosity lubricants to achieve step-out FE
performance. Low viscosity synthetic base stocks (kinematic
viscosity of 2-3 cSt at 100.degree. C.) are currently commercially
available (for example 2 cSt PAO). However these low viscosity
synthetic base stocks are too volatile to be used for formulating
next-generation ultra-low viscosity engine oils (i.e., SAE "0W-4",
SAE 0W-8, SAE 0W-12, etc.).
[0004] Automotive engine oils typically conform to the SAE J300
metric for grading engine oil viscosity. For each SAE engine oil
grade (e.g., 0W-4, 0W-8, 0W-12, 5W-10, 5W-20, 10W-30, etc.) there
are maximum and minimum viscosity requirements at both high and low
temperatures. Typically, such high temperature viscosity
requirements are expressed as a permitted range of kinematic
viscosity at 100.degree. C. determined pursuant to ASTM D445
("KV100"), and such low temperature viscosity requirements are
expressed as a permitted range of cold cranking simulator viscosity
determined pursuant to ASTM D5293 ("CCSV"). For example, the
requirements for a 0W grade engine oil include a KV100 of at least
3.8 cSt, and a CCSV at -35.degree. C. no higher than 6,200
mPas.
[0005] Recently, API Group IV base stocks, which are
polyalpha-olefins ("PAO"), have found wide use in high-quality
engine oils in various grades, gear box lubricants, and industrial
oils. Currently low-viscosity Group IV PAO base stocks having a
KV100 in the range from 3 to 10 cSt made from oligomerization of
alpha-olefin monomer(s) comprising 8-12 carbon atoms in the
presence of a Lewis acid catalyst such as BF.sub.3 ("conventional
low-viscosity PAO") are commercially available. These conventional
low-viscosity PAO base stocks are substantially free of dimers of
the monomer(s), and tend to comprise trimers and/or higher
oligomers of the alpha-olefin monomer(s) at various concentrations.
The trimer and higher oligomer molecules in these base stocks tend
to be highly branched (containing more than 2 branches per oligomer
molecule on average). While these base stocks provide good
performances, to formulate high-quality engine oils for the newer
generation engines of modern automobiles, base stocks with even
lower viscosity, higher viscosity index, low Noack volatility, and
high blending performances in terms of blended to CCSV are
needed.
[0006] Lubricant oxidative stability is one of the key parameters
controlling oil life, which translates in oil drain interval in
practical terms. Additionally, deposit formation is an issue
associated with the decomposition of the base stock molecules
mostly propagated by oxidative chain reactions. There are several
conventional approaches to improve the resistance to oxidation of a
finished lubricant product, but most products are formulated using
small molecules such as diphenylamine (DPA) or a phenolic
antioxidant. Improved oxidation stability is necessary to increase
oil life and oil drain intervals, thus reducing the amount of used
oil generated as a consequence of more frequent oil changes. Longer
oil life and oil drain intervals are key benefits that are
desirable to end customers. Traditional antioxidant packages
provide standard protection leaving the main differentiation
hinging on the quality of the base stock in the formulation.
[0007] Currently available commercial low-viscosity PAO base stocks
do not adequately allow formulation of ultra-low viscosity
lubricants while still meeting API specification (e.g., Noack
volatility of 15% or less). New low viscosity engine oils, which
meet the API Noack volatility limit are needed to allow for
improvements in fuel efficiency while maintaining acceptable
oxidative stability. In particular, there is a need for an
ultra-low viscosity engine oil incorporating a low viscosity
synthetic base stock having controlled volatility that would enable
the finished ultra-low viscosity lubricant to achieve step-out FE
performance while also providing for low friction (traction) and
oxidation performance benefits relative to currently commercially
available engine oils incorporating low viscosity Group IV PAO.
SUMMARY
[0008] It has been surprisingly and unexpectedly discovered that
lubricating oil compositions including a major amount of a low
viscosity synthetic base stock comprising oligomers of linear
mono-olefin(s) having 14 or 16 carbon atoms or mixtures thereof
made by using conventional Lewis acid catalyst comprising dimers
and optionally trimers with a minor amount of one or more
lubricating oil additives provide a lubricating oil composition
with a high-viscosity-index, a low pour point with excellent
oxidative stability and traction performance. These lubricating oil
compositions are suitable for high-quality engine oils that provide
for improved fuel economy.
[0009] A first aspect of this disclosure relates to a lubricating
oil composition comprising from 10 to 90 wt % of a base stock
comprising a C28-C32 hydrocarbon fraction ("dimers") and optionally
a C42-C48 hydrocarbon fraction ("trimers") produced by
oligomerization of a linear C14 mono-olefin, a linear C16
mono-olefin, or a mixture thereof, in the presence of a Lewis acid
catalyst, and the remainder of the composition comprising one or
more lubricating oil additives. The lubricating oil composition
provides an oxidation stability test performance of greater than
100 hours (time to 200% KV@40 deg. C. increase) and a mini traction
machine (MTM) average traction coefficient at 100 deg. C. of less
than 0.0081.
[0010] Another aspect of this disclosure relates to a lubricating
oil composition comprising: from 10 to 90 wt % of a base stock
comprising a C28 to C32 hydrocarbon first fraction at a
concentration in the range from 80 to 100 wt %, and a C42 to C48
second fraction at a concentration in the range from 0 to 20 wt %,
based on the total weight of the base stock; wherein the base stock
has a kinematic viscosity at 100.degree. C. as determined pursuant
to ASTM D445 ("KV100") in the range from 3.3 to 4.6 cSt; a pour
point as determined pursuant to ASTM D5850 in the range from -45 to
-10.degree. C.; and a cold-crank-simulator viscosity as determined
pursuant to ASTM D5293 ("CCSV") at -35.degree. C. of at least 500
mPas; and the remainder of the composition comprise one or more
lubricating oil additives. The lubricating oil composition provides
an oxidative stability test performance of greater than 100 hours
(time to 200% KV@40 deg. C. increase) and a mini traction machine
(MTM) average traction coefficient at 100 deg. C. of less than
0.0081.
[0011] Further objects, features and advantages of this disclosure
will be understood by reference to the following drawings and
detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a table showing the physical properties of the
inventive and comparative commercial base stocks of this
disclosure.
[0013] FIG. 2 is a table showing inventive and comparative engine
oil formulations and their physical characteristics and performance
test results of this disclosure.
[0014] FIG. 3 is a table showing inventive and comparative SAE
grade engine oils formulations and their physical characteristics
of this disclosure.
DETAILED DESCRIPTION
Definitions
[0015] "About" or "approximately"--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.
[0016] "Major amount" 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.
[0017] "Minor amount" as it relates to components included within
the lubricating oils of the to 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 less 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.
[0018] "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).
[0019] "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, antioxidants,
detergents, dispersants, antiwear additives, corrosion inhibitors,
viscosity modifiers, metal passivators, pour point depressants,
seal compatibility agents, antifoam agents, extreme pressure
agents, friction modifiers and combinations thereof.
[0020] "Alkyl group" refers to a saturated hydrocarbyl group
consisting of carbon and hydrogen atoms.
[0021] "Hydrocarbyl group" refers to a group consisting of hydrogen
and carbon atoms only. A hydrocarbyl group can be saturated or
unsaturated, linear or branched, cyclic or acyclic, and aromatic or
non-aromatic.
[0022] "Hydrocarbon" refers to a compound consisting of carbon
atoms and hydrogen atoms.
[0023] "Alkane" refers to a hydrocarbon that is completely
saturated. An alkane can be linear, branched, cyclic, or
substituted cyclic.
[0024] "Olefin" refers to a non-aromatic hydrocarbon comprising one
or more carbon-carbon double bond in the molecular structure
thereof.
[0025] "Mono-olefin" refers to an olefin comprising a single
carbon-carbon double bond.
[0026] "Cn" group or compound refers to a group or a compound
comprising carbon atoms at total number thereof of n. Thus, "Cm-Cn"
group or compound refers to a group or compound comprising carbon
atoms at a total number thereof in the range from m to n. Thus, a
C1-C50 alkyl group refers to an alkyl group comprising carbon atoms
at a total number thereof in the range from 1 to 50.
[0027] "Carbon backbone" refers to the longest straight carbon
chain in the molecule of the compound or the group in question.
"Branch" refer to any substituted or unsubstituted hydrocarbyl
group connected to the carbon backbone. A carbon atom on the carbon
backbone connected to a branch is called a "branched carbon."
[0028] "Epsilon-carbon" in a branched alkane refers to a carbon
atom in its carbon backbone that is (i) connected to two hydrogen
atoms and two carbon atoms and (ii) connected to a branched carbon
via at least four (4) methylene (CH.sub.2) groups. Quantity of
epsilon carbon atoms in terms of mole percentage thereof in a
alkane material based on the total moles of carbon atoms can be
determined by using, e.g., .sup.13C NMR.
[0029] "SAE" refers to SAE International, formerly known as Society
of Automotive Engineers, which is a professional organization that
sets standards for internal combustion engine lubricating oils.
[0030] "SAE J300" refers to the viscosity grade classification
system of engine lubricating oils established by SAE, which defines
the limits of the classifications in rheological terms only.
[0031] "Base stock" or "base oil" interchangeably refers to an oil
that can be used as a component of lubricating oils, heat transfer
oils, hydraulic oils, grease products, and the like.
[0032] "Lubricating oil" or "lubricant" interchangeably refers to a
substance that can be introduced between two or more surfaces to
reduce the level of friction between two adjacent surfaces moving
relative to each other. A lubricant base stock is a material,
typically a fluid at various levels of viscosity at the operating
temperature of the lubricant, used to formulate a lubricant by
admixing with other components. Non-limiting examples of base
stocks suitable in lubricants include API Group I, Group II, Group
III, Group IV, and Group V base stocks. PAOs, particularly
hydrogenated PAOs, have recently found wide use in lubricants as a
Group IV base stock, and are particularly preferred. If one base
stock is designated as a primary base stock in the lubricant,
additional base stocks may be called a co-base stock.
[0033] "In the vicinity of" a given temperature means within the
range from 10.degree. C. lower than that temperature to 10.degree.
C. higher than that temperature.
[0034] "Substantially saturated" means at least 90%, preferably at
least 95%, more preferably at least 98%, by mole, of the molecules
in question are saturated, based on the total moles of the relevant
molecules.
[0035] "Substantially free" of the monomer(s) means a material
comprises the monomer(s) at a total concentration thereof, of no
more than 5%, preferably no more than 3%, more preferably no more
than 1%, by weight, based on the total weight of the material.
[0036] All kinematic viscosity values in this disclosure are as
determined pursuant to ASTM D445. Kinematic viscosity at
100.degree. C. is reported herein as KV100, kinematic viscosity at
40.degree. C. is reported herein as KV40 and kinematic viscosity at
25.degree. C. is reported herein as KV25. Units of all KV100, KV40
and KV25 values herein are cSt unless otherwise specified.
[0037] All viscosity index ("VI") values in this disclosure are as
determined pursuant to ASTM D2270.
[0038] All Noack volatility ("NV") values in this disclosure are as
determined pursuant to ASTM D5800 unless specified otherwise. Unit
of all NV values is wt %, unless otherwise specified.
[0039] All pour point values in this disclosure are as determined
pursuant to ASTM D5950 or D97.
[0040] All CCS viscosity ("CCSV") values in this disclosure are as
determined pursuant to ASTM 5293. Unit of all CCSV values herein is
millipascal second (mPas, which is equivalent to centipoise),
unless specified otherwise. All CCSV values are measured at a
temperature of interest to the lubricating oil formulation or oil
composition in question. Thus, for the purpose of designing and
fabricating engine oil formulations, the temperature of interest is
the temperature at which the SAE J300 imposes a minimal CCSV.
[0041] All percentages in describing chemical compositions herein
are by weight unless specified otherwise. "Wt. %" means percent by
weight.
Lubricating Oil Compositions Containing Dimer Base Stock of this
Disclosure
[0042] In this disclosure, a "lubricating oil composition or
formulation" refers to lubricating oil product that can be directly
used to lubricate the interface between two surfaces moving
relative to each other without the need to add any additional
material. A lubricating oil composition in this disclosure can be,
among others: (i) a pure base stock and one or more lubricating oil
additives, and (ii) a mixture of a base stocks (for example, a
first base stock and a second base stock or cobase stock) and one
or more lubricating oil additives. Therefore, to make a final
lubricating oil composition or formulation of a product, one may
add additional components, such as other base stocks, additional
quantities of the materials already present in the oil composition,
additive components, and the like.
[0043] While it is possible the oil composition of this disclosure
contains the base stock as a primary base stock, or even as a
single base stock, it is preferable to include the base stock as a
co-base stock in combination with one primary base stock and
optionally one or more additional co-base stocks. In addition to
the base stocks, the oil composition of this disclosure may further
comprise additive components.
[0044] More particularly, this disclosure relates to lubricating
oil compositions including a low viscosity low volatility base
stock (for example 3.5 cSt) including a C28-C32 hydrocarbon
fraction ("dimers") and optionally a C42-C48 hydrocarbon fraction
("trimers") made by using a conventional Friedel-Crafts BF3
catalyst and higher molecular weight alpha olefin (1-tetradecene)
to and one or more lubricating oil additives that provides for
improved oxidative stability and friction (traction) performance.
The low viscosity base stock including a C14 dimer (C28 Group IV
base stock) has a novel structure, as demonstrated by 1H and 13C
NMR methyl hydrogen and epsilon carbon contents and ratio, which
provides for the improvement in physical properties and performance
characteristics when incorporated into a lubricating oil
composition. The lubricating oil compositions including the C14
dimer have low Noack volatility and improved fuel economy when used
as engine oils relative to comparable lubricating oil compositions
including low viscosity PAO as the base stock.
[0045] In one advantageous form of the lubricating oil composition
of this disclosure includes from 10 to 90 wt % of a base stock
comprising a C28-C32 hydrocarbon fraction ("dimers") and optionally
a C42-C48 hydrocarbon fraction ("trimers") produced by
oligomerization of a linear C14 mono-olefin, a linear C16
mono-olefin, or a mixture thereof, in the presence of a Lewis acid
catalyst, and the remainder of the composition comprising one or
more lubricating oil additives. The lubricating oil composition
provides an oxidative stability test performance of greater than
100 hours (time to 200% KV@40 deg. C. increase) and a mini traction
machine (MTM) average traction coefficient at 100 deg. C. of less
than 0.0081.
[0046] In another advantageous form of the lubricating oil
composition of this disclosure includes from 10 to 90 wt % of a
base stock comprising a C28 to C32 hydrocarbon first fraction at a
concentration in the range from 80 to 100 wt %, and a C42 to C48
second fraction at a concentration in the range from 0 to 20 wt %,
based on the total weight of the base stock; wherein the base stock
has a kinematic viscosity at 100.degree. C. as determined pursuant
to ASTM D445 ("KV100") in the range from 3.3 to 4.6 cSt; a pour
point as determined pursuant to ASTM D5850 in the range from -45 to
-10.degree. C.; and a cold-crank-simulator viscosity as determined
pursuant to ASTM D5293 ("CCSV") at -35.degree. C. of at least 500
mPas; and the remainder of the composition comprise one or more
lubricating oil additives. The lubricating oil composition provides
an oxidative stability test performance of greater than 100 hours
(time to 200% KV@40 deg. C. increase) and a mini traction machine
(MTM) average traction coefficient at 140 deg. C. of less than
0.0081.
[0047] Preferred lubricating oil compositions of this disclosure
exhibit an oxidative stability test performance (time to 200% KV@40
deg. C. increase) of greater than 100 hours, or greater than 110
hours, or greater than 120 hours, or greater than 130 hours.
[0048] Preferred lubricating oil compositions of this disclosure
exhibit a mini traction machine (MTM) average traction coefficient
at 100 deg. C. of less than 0.0081, or less than 0.0079, or less
than 0.0077, or less than 0.0075, or less than 0.0073, or less than
0.0071.
[0049] Preferred lubricating oil compositions of this disclosure
exhibit a kinematic viscosity at 25.degree. C. (KV25) that is at
least 0.5%, or at least 1.0%, or at least 5%, or at least 7%, or at
least 10%, or at least 12% lower or less relative to a comparable
lubricating oil composition not including the C28-C32 hydrocarbon
fraction ("dimers"). In addition, the preferred lubricating oil
compositions of this disclosure exhibit a cold-crank-simulator
viscosity ("CCSV") at -35.degree. C. that is at least 5%, or at
least 10%, or at least 15%, or at least 20%, or at least 25%, or at
least 30% lower or less relative to a comparable lubricating oil
composition not including the C28-C32 hydrocarbon fraction
("dimers").
[0050] Preferred lubricating oil compositions of this disclosure
exhibit a KV100 in a range from kv1 to kv2, where kv1 and kv2 can
be 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5,
8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5,
14.0, 14.5, 15.0, as long as kv1<kv2.
[0051] Engine oil lubricant grades are determined pursuant to SAE
J300 specifications. The low temperature (W) grades (i.e. 10W-xx,
5W-xx, and 0W-xx) are determined by the performance in a
combination of viscosity tests including cold crank simulation
(CCS) (ASTM D5293) and low-temperature pumping viscosity (ASTM
D4684). The high temperature grading for an engine oil (i.e.,
XW-20, XW-30) is determined by kinematic viscosity at 100.degree.
C. (ASTM D445) and high-temp high-shear viscosity (ASTM D4683).
[0052] The lubricating oil compositions of this disclosure may
advantageously exhibit a VI in the range from about 30 to about
200, preferably from about 35 to about 180, more preferably from
about 40 to about 150.
[0053] The lubricating oil compositions of this disclosure
advantageously exhibit a Noack Volatility (NV) value of no greater
than 20%, preferably no greater than 18%, 16%, 15%, 14%, 12%, 10%,
or even 8%.
[0054] The lubricating oil compositions of this disclosure are
particularly advantageous as engine oil for internal combustion
engines, including gas engines, diesel engines, natural gas
engines, four-stroke engines, two-stroke engines, and rotary
engines. The engine oil can be placed into the crank case of the
engine to provide the necessary lubrication and cooling effect for
the engine during normal operation. The low KV100, coupled with the
CCSV of the oil enabled by the use of the base stock makes it
particularly fuel efficient. The engine oils are particularly
advantageous as passenger vehicle engine oil (PVEO) products.
Dimer Base Stocks of the Lubricating Oil Compositions of this
Disclosure
[0055] The lubricating oil compositions of this disclosure include
a base stock comprising a C28-C32 hydrocarbon fraction ("dimers")
and optionally a C42-C48 hydrocarbon fraction ("trimers") (referred
to as the base stock of this disclosure) produced by dimerization
and trimerization of a linear C14 mono-olefin, a linear C16
mono-olefin, or a mixture thereof, as the monomer in the presence
of a Lewis acid catalyst such as BF.sub.3. The base stock of this
disclosure can be substantially unsaturated or substantially
saturated. Preferably, the base stock of this disclosure is
substantially saturated, especially if it is intended for use in
lubricating oil compositions, heat transfer oils, and hydraulic
oils desired to have a long service life. If unsaturated, at least
some of the dimer and/or trimer molecules comprise a carbon-carbon
double bond, which are highly reactive and can cause instability to
the base stock during use. The reactivity of such carbon-carbon
double bonds can make such unsaturated base stock useful as
intermediates for making other chemical materials by reacting with
functionalizing agents to produce, among others, functionalized
dimers and/or trimers.
[0056] The base stock of this disclosure can be advantageously
substantially free of the C14 and/or C16 monomer(s) and the
hydrogenated alkanes thereof. Such monomers and hydrogenated
alkanes thereof, if present in the base stock at high quantity, can
cause the base stock to have a high Noack volatility, which is
highly undesirable.
[0057] The dimer molecules in the base stock of this disclosure are
typically branched hydrocarbons, preferably branched alkanes,
having a long carbon backbone. Thus, for the dimer molecules
derived from two C14 mono-olefin molecules, the long carbon
backbone can comprise, e.g., 20, 21, 22, 23, 24, 24, 25, 26, or 27
carbon atoms. For dimer molecules derived from two C16 mono-olefin
molecules, the long carbon backbone can comprise, e.g., 24, 25, 26,
27, 28, 29, 30, or 31 carbon atoms. For dimer molecules derived
from one C14 mono-olefin molecule and one C16 mono-olefin molecule,
the long carbon backbone can comprise, e.g., 22, 23, 24, 25, 26,
27, 28, or 29 carbon atoms. The dimer molecules can comprise one or
more branches connected to the carbon backbone. The dimer molecules
of the base stock of this disclosure comprise, on average per
molecule, more than one (1) branches connected to the carbon
backbone. Preferably, the dimer molecules of the base stock of this
disclosure comprise, on average per molecule, less than two (2)
branches connected to the carbon backbone. Preferably, the dimer
molecule of the base stock of this disclosure comprises, on average
per molecule, from 1.1 to 1.9 branches, 1.2 to 1.8 branches, 1.3 to
1.7 branches, 1.4 to 1.6 branches, or 1.5 to 1.6 branches. Average
number of branches in an alkane material can be determined using
.sup.13C NMR. Compared to the dimer molecule of 1-tetradecene made
by coordination insertion oligomerization using a metallocene
catalyst, the dimer molecules in the base stock of this disclosure
tend to have significantly higher number of branches on average per
molecule. Without intending to be bound by a particular theory, it
is believed this is due to the use of Lewis acid catalyst such as
BF.sub.3 in the process of making the material, which
simultaneously catalyzes the oligomerization reactions between the
monomer molecules, the isomerization of the monomer molecules and
other reactions, leading to multiple branches with various length
in the dimer molecules. On the other hand, compared to the trimer
molecules of 1-decene made by oligomerization catalyzed by similar
Lewis-acid catalyst such as BF.sub.3, the dimer molecules in the
base stock of this disclosure tend to have significantly higher
linearity characterized by a longer carbon backbone and much fewer
branches connected to the carbon backbone. The significantly higher
linearity renders the dimer molecules in the base stock of this
disclosure significantly waxier than the 1-decene trimer molecules,
which is believed to cause many surprising, interesting and
advantageous lubricant properties of the base stocks of this
disclosure, as the Examples section of this disclosure clearly
demonstrates.
[0058] The trimer molecules in the base stock of this disclosure
are branched hydrocarbons, preferably branched alkanes. Because
they are produced from the oligomerization of three monomer
molecules, they tend to have, on average per molecule, higher
number of branches connected to the carbon backbone therein than
the dimers. It is believed that the trimers in the base stock of
this disclosure resembles the molecular structures of the trimers
made from C8-C12 linear alpha-olefins in conventional low-viscosity
base stocks commercially available discussed above.
[0059] The base stock of this disclosure preferably comprises
predominantly dimers. Thus, the base stock of this disclosure can
comprise the dimers at a concentration in the range from c1 to c2
wt %, based on the total weight of the base stock, where c1 and c2
can be, independently: 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,
91, 92, 93, 94, 95, 96, 97, 98, 99, or 100, as long as c1<c2.
Preferably c1=80 and c2=100; more preferably c1=82 and c2=99; still
more preferably c1=85 and c2=98, still more preferably c1=86 and
c2=96, still more preferably c1=88 and c2=95, and still more
preferably c1=90 and c2=94. For the base stocks made from the same
monomer composition, the higher the concentration of the dimers,
the lower the KV100 of the base stock tends to be.
[0060] The base stock of this disclosure, including but not limited
to those having the feature(s) described above, can preferably
comprise the trimers as a minor component. Thus, the base stock of
this disclosure can comprise the trimers at a concentration in the
range from c3 to c4 wt %, based on the total weight of the base
stock, where c3 and c4 can be, independently: 0, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, as long as
c3<c4. Preferably c3=0 and c4=20; more preferably c3=2 and
c4=18; still more preferably c3=4 and c4=16, still more preferably
c3=5 and c4=85, still more preferably c3=5 and c4=86; still more
preferably c3=5 and c4=88; and still more preferably c3=5 and
c4=90. For the base stocks made from the same monomer composition,
the higher the concentration of the trimers, the higher the KV100
of the base stock tends to be. A high concentration of dimers in
the base stock of this disclosure imparts very interesting
lubricant properties to the base stocks of this disclosure
surprisingly suitable for formulating high-quality low-viscosity
engine oils, especially those in the 0W grade.
[0061] The base stock of this disclosure, including but not limited
to those having the feature(s) described above, can preferably
comprise the dimers and trimers combined at a total concentration
thereof of at least 95 wt %, or at least 96 wt %, or at least 97 wt
%, or at least 98 wt %, or at least 99 wt %, or at least 99.5 wt %,
or at least even 99.9 wt %, based on the total weight of the base
stock.
[0062] The base stock of this disclosure, including but not limited
to those having the feature(s) described above, preferably
comprises a C56-C64 hydrocarbon fraction ("tetramers") and
hydrocarbon fractions with even larger number of carbon atoms in
molecules thereof, if any at all, at a total concentration thereof
no higher than 5 wt %, preferably no higher than 4 wt %, more
preferably no higher than 3 wt %, still more preferably no higher
than 2 wt %, still more preferably no higher than 1 wt %, still
more preferably no higher than 0.8 wt %, still more preferably no
higher than 0.5 wt %, still more preferably no higher than 0.1 wt
%, based on the total weight of the base stock. A high
concentration of the tetramers can lead to a high kinematic
viscosity at 100.degree. C. of the base stock, which can be
undesirable for formulating low-viscosity lubricants.
[0063] The base stock of this disclosure, including but not limited
to those having the feature(s) described above, can desirably
exhibit a pour point determined pursuant to ASTM D5950 in the range
from -45 to -10.degree. C., preferably in the range from -40 to
-15.degree. C., more preferably from -40 to -20.degree. C., still
more preferably from -40 to -25.degree. C., still more preferably
from -40 to -30.degree. C., still more preferably from -40 to
-35.degree. C. Compared to other low-viscosity Group IV base stocks
made from C8-C12 linear alpha-olefin monomer(s) by Lewis-acid
catalyzed oligomerization reactions ("conventional low-viscosity
PAO base stocks") having similar kinematic viscosity at 100.degree.
C., the base stocks of this disclosure exhibit significantly higher
pour points, as demonstrated by the examples section of this
disclosure. However, surprisingly, the high pour points of the base
stocks of this disclosure do not prevent them from blending
successfully with conventional PAO base stocks to form
high-quality, low-viscosity engine oils.
[0064] The base stocks of this disclosure, including but not
limited to those having the feature(s) described above, can
desirably exhibit a kinematic viscosity at 100.degree. C.
determined pursuant to ASTM D445 in the range from 3.0 to 5.0 cSt,
preferably from 3.2 to 4.8 cSt, more preferably from 3.3 to 4.5
cSt, still more preferably from 3.4 to 4.2 cSt, and still more
preferably from 3.5 to 4.0 cSt. The low KV100 of these base stocks
of this disclosure render them particularly suitable as candidate
for primary base stock and/or co-base stocks useful for engine oils
and other lubricants requiring a low KV100 for the formulation.
[0065] The base stocks of this disclosure, including but not
limited to those having the feature(s) described above, can
desirably exhibit a high viscosity index in the range from 120 to
170, preferably from 125 to 165, more preferably from 130 to 160,
still more preferably from 135 to 155. As shown in the Examples
section of this disclosure, compared to conventional low-viscosity
PAO base stocks, the base stocks of this disclosure tend to have
significantly higher viscosity index, which is highly desirable for
engine oils and other lubricant products, as well as heat transfer
oils and hydraulic oils.
[0066] The base stocks of this disclosure, including but not
limited to those having the feature(s) described above, can
desirably exhibit a Noack volatility determined pursuant to ASTM
D5800 no higher than 20 wt %, preferably no higher than 18 wt %,
more preferably no higher than 17 wt %, and still more preferably
no higher than 15 wt %.
[0067] The base stocks of this disclosure, including but not
limited to those having the feature(s) described above, can
desirably exhibit the following properties when blended with a
conventional polyalphaolefin base stock made from C8-C12 linear
alphaolefin feed by Lewis acid catalysis having a KV100 of about
4.0 cSt (e.g., in the range from 4.0 to 4.2 cSt), a pour point at
most -50.degree. C. (preferably at most -60.degree. C., still more
preferably at most -65.degree. C.) ("PAO reference base stock"), to
form a first mixture oil comprising the base stock based on the
total weight of the first mixture oil, a second mixture oil
comprising 20 wt % of the base stock based on the total weight of
the second mixture oil, and a third mixture oil comprising 30 wt %
of the base stock based on the total weight of the base stock, at
least one of the following is met: (i) the first mixture oil
exhibits a lower CCSV at -35.degree. C. than the PAO reference base
stock; (ii) the second mixture oil exhibits a lower CCSV at
-35.degree. C. than the PAO reference base stock; and (iii) the
third mixture oil exhibits a lower CCSV at -35.degree. C. than the
PAO reference base stock. Preferably at least one of the following
is met: (i) the first mixture oil exhibits a CCSV at -35.degree. C.
at least 50 mPas lower than that of the PAO reference base stock;
(ii) the second mixture oil exhibits a CCSV at -35.degree. C. at
least 50 mPas lower than that of the PAO reference base stock; and
(iii) the third mixture oil exhibits a CCSV at -35.degree. C. at
least 50 mPas lower than that of the PAO reference base stock.
Preferably, the base stock exhibits a CCSV at -35.degree. C. higher
than that of the PAO reference base stock. In certain embodiments,
the base stock preferably exhibits a CCSV at -35.degree. C. higher
than 2000 mPas. Even though the base stock in neat form exhibits
such a high CCSV at -35.degree. C., its binary mixtures with the
PAO reference base stock nonetheless can exhibit a CCSV at
-35.degree. C. lower than that of the PAO reference base stock and
that of the base stock itself. This interesting CCSV behavior of
the base stock of this disclosure is very surprising. In other
embodiments, the base stock of this disclosure can exhibit a CCSV
at -35.degree. C. of lower than 1000 mPas (e.g., a base stock
comprising at least 90 wt % of dimers of C14 linear alpha-olefins),
such low CCSV at -35.degree. C. of such base stock of this
disclosure is conducive to a CCSV at -35.degree. C. of the mixtures
comprising it and the PAO reference base stock. The CCSV-lowering
behavior of the base stock of this disclosure can be observed as
well when mixed with conventional low-viscosity PAO base stocks
with other viscosities, such as about 5, 6, 7, 8, 9, or 10 cSt, or
even with Group II and III base stocks. The CCSV-lowering behavior
of the base stock of this disclosure when combined with
conventional low-viscosity PAO base stocks and Group II or III base
stocks renders it particularly advantageous in formulating engine
oils in the 0W grade and other winter grades as a co-base stock
with a primary conventional low-viscosity PAO base stock or Group
II or III base stock.
Method for Making the Dimer Base Stock of This Disclosure
[0068] The base stock of this disclosure is made by oligomerization
of a C14 linear mono-olefin, a C16 linear mono-olefin, or a mixture
of a C14 and C16 linear mono-olefin in the presence of a catalyst
system comprising a Lewis acid such as BF.sub.3 or AlCl.sub.3. The
process preferably comprises the following steps: (I) providing an
olefin monomer feed comprising a C14 linear mono-olefin, a C16
linear mono-olefin, or a mixture thereof; (II) contacting the
olefin monomer(s) with a catalyst system comprising a Lewis acid in
at least one oligomerization reactor under oligomerization
conditions to obtain an oligomerization reaction mixture comprising
unreacted olefin monomer(s), dimers, trimers, and the catalyst
system; (III) quenching the oligomerization reaction mixture; (IV)
removing the unreacted monomer(s) from the quenched oligomerization
reaction mixture after step (III) to obtain an unsaturated product
precursor; and (V) optionally hydrogenating the unsaturated product
precursor in a hydrogenation reactor in the presence of hydrogen
under hydrogenation conditions to obtain a hydrogenated oligomer
oil; and (VI) obtaining the base stock comprising dimers and
optionally trimers from the unhydrogenated product precursor or
hydrogenated dimers and optionally hydrogenated trimers from the
hydrogenated oligomer oil. In an alternative process, step (V) of
hydrogenating the unsaturated product precursor is omitted, and the
base stock comprising unsaturated dimers and unsaturated trimers
can be obtained directly from the unsaturated product precursor. In
one specific embodiment, the unsaturated product precursor
comprising the unsaturated dimers and trimers can be used as the
base stock of this disclosure as is. Preferably the process for
making the base stock of this disclosure includes steps (V) and
(VI) above, and the thus-produced base stock comprises saturated
dimers and trimers.
[0069] The C14 linear mono-olefin can be 1-tetradecene,
2-tetradecene, 3-tetradecene, 4-tetradecene, 5-tetradecene, or
6-tetradecene, or any mixture of two or more thereof, preferably
1-tetradecene. 1-tetradecene is an alpha-olefin; and the rest
internal mono-olefins. Commercially available 1-tetradecene
typically contain some internal C14 mono-olefins above as
impurities. In the oligomerization step (II) above, in the presence
of a strong Lewis acid such as BF.sub.3, 1-tetradecene may
isomerize to form one or more of the internal olefins at various
concentrations thereof, which can undergo dimerization and/or
trimerization reactions with each other and other mono-olefin
monomers to form the oligomerization reaction mixture comprising
the monomers and isomers thereof, dimers, trimers, and higher
oligomers.
[0070] The C16 linear mono-olefin can be 1-hexadecene,
2-hexadecene, 3-hexadecene, 4-hexadecene, 5-hexadecene,
6-hexadecene, or 7-hexadecene, or any mixture of two or more
thereof, preferably 1-hexadecene. While 1-hexadecene is an
alpha-olefin, the rest are internal mono-olefins. Commercially
available 1-hexadecene typically contain some internal C16
mono-olefins above as impurities. In the oligomerization step (II)
above, in the presence of a strong Lewis acid such as BF.sub.3,
1-hexadecene may isomerize to form one or more of the internal
olefins at various concentrations thereof, which can undergo
dimerization and/or trimerization reactions with each other and
other mono-olefin monomers to form the oligomerization reaction
mixture comprising the monomers and isomers thereof, dimers,
trimers, and higher oligomers.
[0071] The oligomerization reactor in step (II) can be a batch
reactor, a semibatch reactor, or a continuous reactor, but
preferably a continuous reactor such as a continuously stirred tank
reactor ("CSTR"). The reactor can include a single vessel, multiple
vessels arranged in parallel, or multiple vessels arranged in
series. In a preferred embodiment, in step (II) the reactor is a
continuous reactor including two reaction vessels connected in
series, wherein the monomers are all charged into the upstream
vessel where oligomerization reactions proceed for a first
residence time, and the effluent from the upstream vessel is fed
into the downstream vessel where oligomerization reactions proceed
for a second residence time to produce the oligomerization reaction
mixture discharged from the second vessel.
[0072] The catalyst system used in the reactor in step (II)
includes a Lewis acid such as BF.sub.3 and AlCl.sub.3, with
BF.sub.3 preferred. Where BF.sub.3 is used, the catalyst system
typically further includes a promoter system including an alcohol
and optionally an ester. Such alcohol useful in the promoter system
include examples such as ethanol, n-propanol, n-butanol,
n-pentanol, and the like. Such ester useful in the promoter system
include examples such as ethyl acetate, n-butyl acetate, and the
like. Many of the alcohols and esters and combinations thereof
described in U.S. Pat. No. 7,544,850 can be used in the
oligomerization step (II) of the process of this disclosure. Among
these, the combination of ethanol and ethyl acetate was found to be
most preferred for making a base stock of this disclosure
comprising dimers as a predominant component (e.g., comprising
dimers at a concentration at least 80 wt % based on the total
weight of the base stock) in that it results in a high conversion
of the C14 and C16 monomer(s) in the reaction, and a high
selectivity toward dimers over trimers and higher oligomers. When
ethanol/ethyl acetate combination is used as the promoter for
BF.sub.3, one can achieve the production of a base stock comprising
predominantly dimers without having to separate the dimers from
higher oligomers in a distillation step after the removal of
monomers in step (IV). When other promoter systems, e.g.,
butanol/butyl acetate, are used, the selectivity toward trimers and
higher oligomers such as tetramers tend to be much higher than when
ethanol/ethyl acetate is used, sometimes necessitating a step of
separating the dimers from such higher oligomers by distillation
after step (IV) in order to produce a base stock comprising dimers
as a predominant component.
[0073] When a catalyst system comprising BF.sub.3, ethanol and
ethyl acetate is used, preferably the molar ratio of the monomer
feed to BF.sub.3 is in the range from 2 to 20, more preferably from
2.5 to 13.5, still more preferably from 3.4 to 10.1, still more
preferably from 4 to 10.1, still more preferably from 4.5 to 9 and
still more preferably from 5 to 8. Preferably the reaction
vessel(s) houses an atmosphere comprising BF.sub.3 gas at an
absolute partial pressure thereof in a range from 3.4 to 170
kilopascal ("kPa"), more preferably from 14 to 100 kPa, still more
preferably from 27 to 69 kPa, and still more preferably from 31 to
37 kPa. Preferably the molar ratio of BF.sub.3 to ethanol is in the
range from 0.5 to 2.0, more preferably from 0.7 to 2.0, still more
preferably from 1 to 2.0, still more preferably from 1.75 to 2.0,
and still more preferably from 1.9 to 2.0. Preferably the molar
ratio of ethanol to ethyl acetate is in the range from 1 to 3, more
preferably from 1 to 2, still more preferably from 1 to 1.5, still
more preferably from 1 to 1.25, still more preferably about 1.
Where the oligomerization reactor comprises two reaction vessels in
series, preferably both vessels house atmosphere having
substantially the same partial pressure of BF.sub.3, and fresh
alcohol and ester, if any, are supplied only to the upstream vessel
and carried forward to the second vessel. Such two-reactor
arrangement is particularly advantageous in that it promotes a high
selectivity toward dimers and a high overall conversion of the
monomers in the oligomerization reactions.
[0074] The preferred total residence time of the olefin monomer
feed in the oligomerization reactor can range from 1 to 20 hours,
more preferably from 1.5 to 15 hours, still more preferably from 2
to 12.5 hours, still more preferably from 3 to 10 hours, and still
more preferably from 4 to 9 hours. Where two reaction vessels are
included in the oligomerization reactor, the residence time in the
upstream and downstream vessels can be the same or different. The
preferred ratio of residence time in the upstream reaction vessel
to the residence time in the downstream reaction vessel can be in
the range from 5 to 1 more preferably from 4 to 1 still more
preferably from 3 to 1.
[0075] The reaction temperature in the oligomerization reactor can
be preferably in the range from 10 to 100.degree. C., more
preferably from 20 to 80.degree. C., still more preferably from 35
to 65.degree. C., still more preferably from 40 to 60.degree. C.,
still more preferably from 45 to 55.degree. C. Where the
oligomerization reactor comprises two reaction vessels in series,
the reaction temperatures in the two vessels can be both in the
above ranges and can be the same or different.
[0076] As described above, on contact with BF.sub.3, a strong Lewis
acid, the monomer olefin molecule(s) in the olefin monomer feed can
undergo isomerization reactions to produce other olefins,
particularly internal olefins if the feed is a linear alpha olefin.
The olefin monomer molecules can react with each other and their
isomers to produce dimer molecules with various carbon backbones
having various branches. Compared to dimers made from linear
alpha-olefin molecules in the presence of a coordination insertion
polymerization catalyst such as a metallocene catalyst system, the
dimers produced in the process of this disclosure tend to have more
branches connected to the carbon backbone. Thus, the dimer
molecules produced in the process of this disclosure comprise, on
average per dimer molecule, more than one (1) branches connected to
the carbon backbone. Some of the dimer molecules may comprise only
one (1) branch connected to the carbon backbone, some comprise two
(2), and a fraction may comprise more than two (2). Nonetheless,
preferably, the dimer molecules produced in the oligomerization
reactor comprise, on average per molecule, at most 2 branches
connected to the carbon backbone. The relatively low branching and
the relatively long carbon backbones of the dimer molecules result
in relatively high linearity of the molecules, and a relatively
high waxiness and relatively high pour point to a base stock of
this disclosure comprising predominantly dimers, as discussed
above.
[0077] The dimer molecules as produced in the oligomerization
reactor are mono-olefins per se comprising a carbon-carbon double
bond. In the presence of BF.sub.3, the dimer molecules can
isomerize to form terminal or internal olefins. Some of the dimer
molecules or isomers thereof may further react with one additional
monomer molecule to form trimer molecules. Some of the dimer
molecules or isomers thereof may react with each other to form
tetramer molecules. The trimer molecules may react with one
additional monomer molecule to form tetramers. Higher oligomers
than tetramers can be formed as well. On average, the higher the
degree of polymerization required for producing an oligomer, the
higher the number of branches connected to the carbon backbone of
the oligomer molecule. Thus, on average, tetramers comprise higher
number of branches connected to their carbon backbones than
trimers, which, in turn, comprise higher number of branches
connected to their backbones than dimers. The higher branching of
trimers than dimers leads to less linearity of the trimer molecules
than the dimer molecules, hence less waxiness thereof.
[0078] The oligomerization reaction mixture exiting or taken out of
the oligomerization reactor is a mixture comprising unreacted
olefin monomer(s), isomers of the olefin monomer(s), dimers of the
olefin monomer(s), trimers of the olefin monomer(s), and higher
oligomers such as tetramers, and the catalyst system comprising
BF.sub.3 and the promoter(s). The oligomerization reaction mixture
can be quenched by adding an excessive quantity of the promoter, or
an alkaline aqueous solution such as NaOH aqueous solution, to
deactivate the BF.sub.3 catalyst.
[0079] The quenched oligomerization reaction mixture can then be
distilled to remove the unreacted monomer(s) and isomers thereof
and the residual alcohol/ester promoters to yield an unsaturated
product precursor. While the unsaturated product precursor can be
used as a base stock per se given its lubricant properties, it is
preferred that the unsaturated product precursor is hydrogenated in
a hydrogenation reactor in the presence of hydrogen under
hydrogenation conditions to obtain a hydrogenated oligomer oil that
is substantially completely saturated, i.e., substantially all of
carbon-carbon double bonds in the oligomer molecules have been
hydrogenated. Such hydrogenation conditions can include the
presence of a hydrogenation catalyst comprising metals such as Fe,
Co, Ni, Re, Pd, Pt, Rh, Ru, and the like. A preferred hydrogenation
catalyst is Raney nickel. Filtration of the catalyst particles from
the hydrogenation reaction mixture exiting the hydrogenation
reactor yields a hydrogenated oligomer oil. The hydrogenated
oligomer oil, comprising saturated dimers and optionally trimers
and higher oligomers, can be used directly as a base stock.
Alternatively, the hydrogenated oligomer oil may be further
separated by distillation to obtain fractions rich in dimers,
trimers, or higher oligomers, which can be used as base stocks of
various viscosity grades.
[0080] Examples of techniques that can be employed to characterize
the base stock described above include, but are not limited to,
analytical gas chromatography, nuclear magnetic resonance,
thermogravimetric analysis (TGA), inductively coupled plasma mass
spectrometry, differential scanning calorimetry (DSC), and
volatility and viscosity measurements.
Other Lubricating Oil Base Stocks in the Lubricating Oil
[0081] A wide range of other lubricating oil base stocks known in
the art can be used in conjunction with the dimer base stock in the
lubricating oil compositions of the instant disclosure as primary
base stock or co-base stock. Such other base stocks can be either
derived from natural resources or synthetic, including un-refined,
refined, or re-refined oils. Un-refined oil base stocks include
shale oil obtained directly from retorting operations, petroleum
oil obtained directly from primary distillation, and ester oil
obtained directly from a natural source (such as plant matters and
animal tissues) or directly from a chemical esterification process.
Refined oil base stocks are those un-refined base stocks further
subjected to one or more purification steps such as solvent
extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation to improve the at least one
lubricating oil property. Re-refined oil base stocks are obtained
by processes analogous to refined oils but using an oil that has
been previously used as a feed stock.
[0082] 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
[0083] 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.
[0084] 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.
[0085] 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.
[0086] 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 C.sub.18 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.
[0087] 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 C14 to C18 olefins are
described in U.S. Pat. No. 4,218,330.
[0088] 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/hydroisomerized 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.
[0089] 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.
[0090] 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.
[0091] 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.
[0092] 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.
[0093] 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.
[0094] 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.
[0095] 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.
[0096] 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.
[0097] 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.
[0098] 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.
[0099] 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.
[0100] 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).
[0101] 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.
[0102] 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.
[0103] 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).
[0104] 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.
Groups II and III base stocks can be included in the lubricating
oil formulations of this disclosure, but preferably only those with
high quality, e.g., those having a VI from 100 to 120. Group IV and
V base stocks, preferably those of high quality, are desirably
included into the lubricating oil formulations of this
disclosure.
[0105] The base oil constitutes the major component of the
lubricating oil compositions of the present disclosure and
typically is present in an amount ranging from about 5 to about 99
weight percent, or about 7 to about 95 weight percent, or about 10
to about 90 weight percent, or about 20 to about 80 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. A second base
stock or co-base stock may be also optionally incorporated into the
lubricating oil compositions of this disclosure in an amount
ranging from about 5 to about 80 weight percent, or about 10 to
about 60 weight percent, or about 15 to about 50 weight percent, or
about 20 to about 40 weight percent, or from about 25 to about 35
weight percent.
Lubricating Oil Additives of the Lubricating Oil Compositions of
this Disclosure
[0106] The lubricating oil compositions (preferably lubricating oil
formulations) of this disclosure may additionally contain one or
more of the commonly used lubricating oil performance additives
including but not limited to dispersants, detergents, viscosity
modifiers, antiwear additives, corrosion inhibitors, rust
inhibitors, metal deactivators, extreme pressure additives,
anti-seizure agents, wax modifiers, viscosity modifiers, fluid-loss
additives, seal compatibility agents, lubricity agents,
anti-staining agents, chromophoric agents, defoamants,
demulsifiers, densifiers, wetting agents, gelling agents, tackiness
agents, colorants, and others. For a review of many commonly used
additives and the quantities used, see: (i) Klamann in Lubricants
and Related Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN
0-89573-177-0; (ii) "Lubricant Additives," M. W. Ranney, published
by Noyes Data Corporation of Parkridge, N J (1973); (iii)
"Synthetics, Mineral Oils, and Bio-Based Lubricants," Edited by L.
R. Rudnick, CRC Taylor and Francis, 2006, ISBN 1-57444-723-8; (iv)
"Lubrication Fundamentals", J. G. Wills, Marcel Dekker Inc., (New
York, 1980); (v) Synthetic Lubricants and High-Performance
Functional Fluids, 2nd Ed., Rudnick and Shubkin, Marcel Dekker
Inc., (New York, 1999); and (vi) "Polyalphaolefins," L. R. Rudnick,
Chemical Industries (Boca Raton, Fla., United States) (2006), 111
(Synthetics, Mineral Oils, and Bio-Based Lubricants), 3-36.
Reference is also made to: (a) U.S. Pat. No. 7,704,930 B2; (b) U.S.
Pat. No. 9,458,403 B2, Column 18, line 46 to Column 39, line 68;
(c) U.S. Pat. No. 9,422,497 B2, Column 34, line 4 to Column 40,
line 55; and (d) U.S. Pat. No. 8,048,833 B2, Column 17, line 48 to
Column 27, line 12, the disclosures of which are incorporated
herein in its entirety. These additives are commonly delivered with
varying amounts of diluent oil that may range from 5 wt % to 50 wt
% based on the total weight of the additive package before
incorporation into the formulated oil.
[0107] Further details of the lubricating oil additives useful in
the lubricating oil compositions of this disclosure are as
follows:
Friction Modifiers
[0108] 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.
[0109] Illustrative friction modifiers may include, for example,
inorganic compounds or to materials, or mixtures thereof.
Illustrative inorganic 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.
[0110] 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.
[0111] 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.
[0112] 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.
[0113] 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.
[0114] 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.
[0115] 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.
[0116] 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.
Antiwear Additives
[0117] 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.
[0118] 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".
[0119] 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.
[0120] 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
[0121] 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 herein form ash upon combustion.
[0122] 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.
[0123] 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.
[0124] 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.
[0125] 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 3,652,616, 3,948,800; and Canada Patent No.
1,094,044.
[0126] 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.
[0127] 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.
[0128] 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.
[0129] 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.
[0130] 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.
[0131] 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.
[0132] 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.
[0133] 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.
[0134] 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).
[0135] 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.
[0136] 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).
[0137] 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.
[0138] 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.
[0139] Another useful class of polymers is polymers prepared by
cationic polymerization of monomers such as isobutene and styrene.
Common polymers from this class include polyisobutenes obtained by
polymerization of a C4 refinery stream having a butene content of
35 to 75% by wt., and an isobutene content of 30 to 60% by wt. A
preferred source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feedstocks are disclosed in
the art such as in U.S. Pat. No. 4,952,739. A preferred embodiment
utilizes polyisobutylene prepared from a pure isobutylene stream or
a Raffinate I stream to prepare reactive isobutylene polymers with
terminal vinylidene olefins. Polyisobutene polymers that may be
employed are generally based on a polymer chain of from 1500 to
3000.
[0140] 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.
[0141] 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.
[0142] 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 to 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.
[0143] 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.
Detergents
[0144] 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.
[0145] 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.
[0146] 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.
[0147] The organic acid or inorganic acid is preferably selected
from a sulfur-containing acid, a carboxylic acid, a
phosphorus-containing acid, and mixtures thereof.
[0148] 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.
[0149] 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.
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.
[0150] 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 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.
[0151] 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, barium, or mixtures thereof. More preferably, M
is calcium.
[0152] 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.
[0153] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0154] 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.
[0155] 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.
[0156] 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.
[0157] 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.
Viscosity Modifiers
[0158] Viscosity modifiers (also known as viscosity index improvers
(VI improvers), and to viscosity improvers) can be included in the
lubricant compositions of this disclosure.
[0159] Viscosity modifiers provide lubricants with high and low
temperature operability. These additives impart shear stability at
elevated temperatures and acceptable viscosity at low
temperatures.
[0160] 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.
[0161] 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.
[0162] 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".
[0163] 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).
[0164] 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 to monomer, and B is a polymeric block derived
predominantly from conjugated diene monomer.
[0165] 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.
[0166] 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
[0167] 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.
[0168] 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).
[0169] 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.
[0170] 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)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.
[0171] 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.
[0172] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0173] 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)
[0174] 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
[0175] 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
[0176] 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
[0177] 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.
[0178] 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.
[0179] 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.
[0180] 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.
[0181] 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.
[0182] 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.
[0183] 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 0.0-5 0.01-1.5 (PPD) Anti-foam Agent 0.001-3 0.001-0.15
Viscosity Modifier (solid 0.1-2 0.1-1 polymer basis) Antiwear 0.2-3
0.5-1 Inhibitor and Antirust 0.01-5 0.01-1.5
[0184] 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.
[0185] This disclosure is further illustrated by the following
non-limiting examples.
Examples
Test Methods
[0186] In all Examples herein, unless specified otherwise, the
following properties are determined pursuant to the following ASTM
standards:
TABLE-US-00003 Properties KV100 KV40 KV25 VI Noack Volatility Pour
Point CCSV ASTM Standard D445 D445 D445 D2270 D5800 D5950 D5293
[0187] Additional bench testing was conducted for the lubricating
oil compositions or formulations of this disclosure. The additional
bench testing included the following: integrated mini traction
machine (MTM) friction at 100 deg. C. as described below;
thermo-oxidation engine oil simulation testing (TEOST 33C-SAE
932837 and SAE 962039). For some formulations, the bench testing
included high temperature high shear (HTHS) viscosity at 150 deg.
C. measured by ASTM D4683.
[0188] The Mini Traction Machine (MTM) is a fully automated
instrument manufactured by PCS Instruments and identified as Model
MTM. The test specimens and apparatus configuration are such that
realistic pressure, temperature and speed can be attained without
requiring very large loads, motors or structures. A small sample of
fluid (50 milliliters) is placed in a test cell and the machine
automatically runs either through a range of speeds, slide-to-roll
ratios, temperatures and loads, or at specifically set temperature,
slide-to-roll ratio and speed range to generate information
regarding the friction performance of a test fluid without further
operator intervention. The working of the MTM is known and familiar
to those of skill in the art. In order to allow for numerical
comparison of the MTM Stribeck traces, an integration method (the
trapezoidal rule) was employed for each curve individually and an
average integrated Stribeck friction coefficient and standard
deviation for all 4 traces were calculated. The average integrated
Stribeck friction coefficient provides a measure of the friction an
engine will see during operation (albeit at different ratios to
those calculated). The MTM integrated area value listed throughout
this disclosure has been calculated using this method.
[0189] Oil life may be assessed using the Oxidative Stability Test
(OST) at 165.degree. C. In the OST, a vial is loaded with 10 mL of
sample, and 50 ppm of Fe in an oil soluble form. There is a head
pressure of air of 50 psi and air is bubbled in the vial at 125
ml/min. The test is run maintaining the temperature at 165.degree.
C. and, at a pre-determined interval, a small aliquot of the sample
is taken out to measure the viscosity at 40.degree. C. The
measurement of the viscosity at 40.degree. C. is similar to ASTM
D445 and the results comparable. Once the viscosity increases over
200% compared to the initial viscosity, the oil is considered
condemned. For the lubricating oil compositions of this disclosure,
the OST (time to 200% KV40 increase) was used to quantify the
oxidative stability of the inventive and comparative oil
compositions.
Inventive and Comparative Lubricating Oil Compositions
[0190] A C28 Group IV base stock, dimer of 1-tetradecene, was used
to formulate low viscosity engine oils and their specifications and
performance test results were compared to engine oil formulations
using commercially available Group IV base oils, e.g., PAO4, PAO3.6
and mPAO3.4, of similar 100 deg. C. kinematic viscosity.
[0191] FIG. 1 is a table that depicts the physical properties of
the inventive base stocks (conventional C14 dimer) and comparative
base stocks (metallocene PAO 3.4, conventional PAO 3.6,
conventional PAO4, m-C14 dimer, Group III-Visom 4, and Group
III-GTL 4) used in the evaluations. All base stocks were low
viscosity having KV100 values ranging from 3.38 to 4.17 cSt. The
MTM average traction coefficient of the inventive conventional C14
dimer was lower than each of the comparative base stocks measured
with the exception of the metallocene C14 dimer. The metallocene
C14 dimer, however, had no measurable value of CCSV at -35.degree.
C., because of its poor low temperature properties while the CCSV
of the inventive conventional C14 dimer was lower than each of the
other comparative base stocks.
[0192] FIG. 2 is a table that depicts the physical characteristics
and performance test results of lubricating oil compositions
including various low viscosity synthetic base stocks. Inventive
lubricating oil compositions included the conventional C14 dimer
and comparative lubricating oil compositions included metallocene
PAO3.4, conventional PAO3.6 and conventional PAO4. Each of the
lubricating oil compositions included 83.2 wt. % of the base stock
with the remainder of the composition being a lubricating oil
additive package. The performance test results for the inventive
and comparative lubricating oil compositions demonstrate the
significantly improved oxidative stability test results and MTM
average traction coefficient test results for the inventive
lubricating oil composition including the conventional C14 dimer
with respect to the comparative lubricating oil compositions. The
relative improvement in oxidative stability of the inventive
lubricating oil composition ranged from 23.7 to 57.9%, while the
relative improvement in traction coefficient of the inventive
lubricating oil composition including the conventional C14 dimer
ranged from 1.7 to 14.3%.
[0193] FIG. 3 is table that depicts the physical characteristics
and low temperature relative viscosity reduction due to the use of
inventive example 1 of SAE grade engine oil formulations using
equal amount of conventional PAO4, conventional PAO3.6 and
conventional C14 dimer. SAE grade engine oils evaluated were 0W-20,
0W-30, 0W-40 and 5W-30. Beneficial reduction of kinematic viscosity
at 25.degree. C. and CCSV at -35.degree. C. was achieved in all SAE
grade engine oils tested when the inventive cC14 dimer was used
relative to the comparative engine oils not including the inventive
cC14 dimer.
[0194] 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.
[0195] This 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.
PCT and EP Clauses:
[0196] 1. A lubricating oil composition comprising from 10 to 90 wt
% of a base stock comprising a C28-C32 hydrocarbon fraction
("dimers") and optionally a C42-C48 hydrocarbon fraction
("trimers") produced by oligomerization of a linear C14
mono-olefin, a linear C16 mono-olefin, or a mixture thereof, in the
presence of a Lewis acid catalyst, and the remainder of the
composition comprising one or more lubricating oil additives,
wherein the lubricating oil composition provides an oxidative
stability of greater than 100 hours (time to 200% KV@40 deg. C.
increase) and a mini traction machine (MTM) average traction
coefficient at 100 deg. C. of less than 0.0081.
[0197] 2. The composition of clause 1, wherein the base stock
exhibits a mole percentage of epsilon-carbons as determined by
.sup.13C NMR of no less than 20 mol %, based on the total moles of
the carbon atoms therein.
[0198] 3. The composition of clauses 1-2, wherein the dimers are at
a concentration in the range from 80 to 100 wt %, and the trimers
are at a concentration in the range from 0 to 20 wt %, based on the
total weight of the base stock.
[0199] 4. The composition of clauses 1-3, wherein the total
concentration of the dimers and the trimers combined is at least 95
wt %, based on the total weight of the base stock.
[0200] 5. The composition of clauses 1-4, wherein the molecules of
the dimers comprise, on average, no more than 2.0 branches attached
to the carbon backbones therein.
[0201] 6. The composition of clauses 1-5, wherein the base stock
has a pour point as determined pursuant to ASTM D5950 of in a range
from -45 to -10.degree. C.
[0202] 7. The composition of clauses 1-6, wherein the base stock
has a cold-crank-simulator viscosity as determined pursuant to ASTM
D5293 ("CCSV") at -35.degree. C. of at least 500 mPas.
[0203] 8. The composition of clauses 1-7, wherein the base stock
has a kinematic viscosity at 100.degree. C. as determined pursuant
to ASTM D445 ("KV100") in the range from 3.3 to 4.6 cSt.
[0204] 9. The composition of clauses 1-8, wherein the base stock
has a CCSV at -35.degree. C. of CCSVmPas; when blended with a PAO
reference base stock made from one or more linear alpha-olefin
monomer(s) comprising 8 to 12 carbon atoms having a KV100 of 4.0 to
4.2 cSt, a pour point of no higher than -50.degree. C., a CCSV at
-35.degree. C. of CCSV(PAO4) mPas, where
1200.ltoreq.CCSV(PAO4).ltoreq.1500, to form a first mixture oil
comprising 10 wt % of the base stock based on the total weight of
the first mixture oil, a second mixture oil comprising 20 wt % of
the base stock based on the second mixture oil, and a third mixture
oil comprising 30 wt % of the base stock based on the total weight
of the base stock, at least one of the following is met: (i) the
first mixture oil exhibits a lower CCSV at -35.degree. C. than the
PAO reference base stock; (ii) the second mixture oil exhibits a
lower CCSV at -35.degree. C. than the PAO reference base stock; and
(iii) the third mixture oil exhibits a lower CCSV at -35.degree. C.
than the PAO reference base stock.
[0205] 10. The composition of clause 9, wherein the base stock
meets at least one of the following: (i) the first mixture oil
exhibits a CCSV at -35.degree. C. at least 50 mPas lower than that
of the PAO reference base stock; (ii) the second mixture oil
exhibits a CCSV at -35.degree. C. at least 50 mPas lower than that
of the PAO reference base stock; and (iii) the third mixture oil
exhibits a CCSV at -35.degree. C. at least 50 mPas lower than that
of the PAO reference base stock.
[0206] 11. The composition of clause 9, wherein the base stock
exhibits a CCSV at -35.degree. C. lower than that of the PAO
reference base stock.
[0207] 12. The composition of clauses 1-11, wherein the one or more
lubricating oil additives are selected from the group consisting of
a detergent, dispersant, viscosity index improver, viscosity
modifier, metal passivator, antioxidant, pour point depressant,
corrosion inhibitor, metal deactivator, seal compatibility
additive, anti-foam agent, anti-rust additive, friction modifier,
extreme pressure agent and combinations thereof, and wherein the
one or more lubricating oil additives comprise from 1 to 30 wt. %
of the lubricating oil composition.
[0208] 13. The composition of clauses 1-12 further including a
cobase stock at from 1 to 30 wt. % of the lubricating oil
composition, wherein the cobase stock is selected from the group
consisting of a Group I base stock, a Group II base stock, a Group
III base stock, a conventional Group IV base stock, a Group V base
stock and combinations thereof.
[0209] 14. The composition of clauses 1-13, wherein the lubricating
oil composition has a kinematic viscosity at 25.degree. C. as
determined pursuant to ASTM D445 ("KV25") at least 0.5% lower than
a comparable lubricating oil composition not including the C28-C32
hydrocarbon fraction ("dimers").
[0210] 15. The composition of clauses 1-14, wherein the lubricating
oil composition has a cold-crank-simulator viscosity as determined
pursuant to ASTM D5293 ("CCSV") at -35.degree. C. at least 5% lower
than a comparable lubricating oil composition not including the
C28-C32 hydrocarbon fraction ("dimers").
[0211] 16. The composition of clauses 1-15, wherein the lubricating
oil composition is used as a passenger vehicle engine oil (PVEO),
commercial vehicle engine oil (CVEO) or a natural gas engine
oil.
[0212] 17. The composition of clauses 1-16, wherein the lubricating
oil composition is an SAE viscosity grade selected from the group
consisting of 0W-30, 5W-30, 0W-20, 5W-20, 0W-16, 5W-16, 0W-12,
5W-12, 0W-8, and 5W-8.
[0213] 18. A lubricating oil composition comprising: from 10 to 90
wt % of a base stock comprising a C28 to C32 hydrocarbon first
fraction at a concentration in the range from 80 to 100 wt %, and a
C42 to C48 second fraction at a concentration in the range from 0
to 20 wt %, based on the total weight of the base stock; wherein
the base stock has a kinematic viscosity at 100.degree. C. as
determined pursuant to ASTM D445 ("KV100") in the range from 3.3 to
4.6 cSt; a pour point as determined pursuant to ASTM D5950 in the
range from -45 to -10.degree. C.; and a cold-crank-simulator
viscosity as determined pursuant to ASTM D5293 ("CCSV") at
-35.degree. C. of at least 500 mPas; and the remainder of the
composition comprising one or more lubricating oil additives,
wherein the lubricating oil composition provides an oxidative
stability of greater than 100 hours (time to 200% KV@40 deg. C.
increase) and a mini traction machine (MTM) average traction
coefficient at 100 deg. C. of less than 0.0081.
* * * * *
References