U.S. patent application number 13/718291 was filed with the patent office on 2013-06-27 for method for improving engine fuel efficiency.
This patent application is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Douglas Edward Deckman.
Application Number | 20130165354 13/718291 |
Document ID | / |
Family ID | 47521172 |
Filed Date | 2013-06-27 |
United States Patent
Application |
20130165354 |
Kind Code |
A1 |
Deckman; Douglas Edward |
June 27, 2013 |
METHOD FOR IMPROVING ENGINE FUEL EFFICIENCY
Abstract
A method for improving fuel efficiency in an engine lubricated
with a lubricating oil by using as the lubricating oil a formulated
oil having a composition comprising: a lubricating oil base stock;
and a viscosity index improver comprising at least one
propylene-based polymer. The at least one propylene-based polymer
comprises from 60 wt % to 98 wt % propylene derived units and from
2 wt % to 40 wt % units derived from one or more other alpha
olefins, a weight average molecular weight (Mw) as measured by GPC
of from 100,000 to 500,000, a number average molecular weight (Mn)
as measured by GPC of from 100,000 to 400,000, a molecular weight
distribution (MWD=Mw/Mn) of from 1 to 2; and a mole ratio of
propylene to one or more other alpha olefins from 50:50 to
85:15.
Inventors: |
Deckman; Douglas Edward;
(Mullica Hill, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company; |
Annandale |
NJ |
US |
|
|
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
47521172 |
Appl. No.: |
13/718291 |
Filed: |
December 18, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61579342 |
Dec 22, 2011 |
|
|
|
Current U.S.
Class: |
508/110 ;
585/12 |
Current CPC
Class: |
C10M 2205/024 20130101;
C10N 2040/25 20130101; C10N 2030/06 20130101; C10M 143/08 20130101;
C10N 2030/54 20200501; C10M 2203/1006 20130101; C10M 2203/1025
20130101; C10M 2205/0285 20130101; C10M 143/00 20130101; C10M
143/06 20130101; C10M 2205/024 20130101; C10M 2205/028 20130101;
C10N 2020/04 20130101; C10M 2205/024 20130101; C10M 2205/026
20130101; C10N 2020/04 20130101; C10M 2203/1025 20130101; C10N
2020/02 20130101; C10M 2205/024 20130101; C10M 2205/028 20130101;
C10N 2020/04 20130101; C10M 2205/024 20130101; C10M 2205/026
20130101; C10N 2020/04 20130101; C10M 2203/1025 20130101; C10N
2020/02 20130101 |
Class at
Publication: |
508/110 ;
585/12 |
International
Class: |
F01M 7/00 20060101
F01M007/00; C10M 107/06 20060101 C10M107/06 |
Claims
1. A method for improving fuel efficiency in an engine lubricated
with a lubricating oil by using as the lubricating oil a formulated
oil having a composition comprising: a lubricating oil base stock;
and a viscosity index improver comprising at least one
propylene-based polymer, said at least one propylene-based polymer
comprising from 60 wt % to 98 wt % propylene derived units and from
2 wt % to 40 wt % units derived from one or more other alpha
olefins, a weight average molecular weight (Mw) as measured by GPC
of from 100,000 to 500,000, a number average molecular weight (Mn)
as measured by GPC of from 100,000 to 400,000, a molecular weight
distribution (MWD=Mw/Mn) of from 1 to 2; and a mole ratio of
propylene to one or more other alpha olefins from 50:50 to 85:15;
wherein fuel efficiency is improved as compared to fuel efficiency
achieved using a lubricating oil containing a viscosity index
improver other than the at least one propylene-based polymer.
2. The method of claim 1 wherein the lubricating oil base stock
comprises a Group I, Group II, Group III, Group IV or Group V base
oil.
3. The method of claim 1 wherein the one or more other alpha
olefins comprise butylene.
4. The method of claim 1 wherein the one or more other alpha
olefins comprise one or more C.sub.4 to C.sub.12 alpha-olefins.
5. The method of claim 1 wherein the weight average molecular
weight (Mw) as measured by GPC is from 150,000 to 450,000, the
number average molecular weight (Mn) as measured by GPC is from
150,000 to 350,000, the molecular weight distribution (MWD=Mw/Mn)
is from 1.0 to 1.75, and the mole ratio of propylene to one or more
other alpha olefins is from 50:50 to 80:20.
6. The method of claim 1 wherein the formulated oil further
comprises one or more dispersants.
7. The method of claim 1 wherein the formulated oil further
comprises one or more pour point depressants.
8. A method for improving fuel efficiency in an engine lubricated
with a lubricating oil by using as the lubricating oil a formulated
oil having a composition comprising: from 60 wt % to 98 wt %, based
on the total weight of the formulated oil, of a lubricating oil
base stock; from 0.5 wt % to 15 wt %, based on the total weight of
the formulated oil, of a viscosity index improver comprising at
least one propylene-based polymer, said at least one
propylene-based polymer comprising from 60 wt % to 98 wt %
propylene derived units and from 2 wt % to 40 wt % units derived
from one or more other alpha olefins, a weight average molecular
weight (Mw) as measured by GPC of from 100,000 to 500,000, a number
average molecular weight (Mn) as measured by GPC of from 100,000 to
400,000, a molecular weight distribution (MWD=Mw/Mn) of from 1 to
2; and a mole ratio of propylene to one or more other alpha olefins
from 50:50 to 85:15; from 0.1 wt % to 20 wt %, based on the total
weight of the formulated oil, of one or more dispersants; and from
0.0 wt % to 5 wt %, based on the total weight of the formulated
oil, of one or more pour point depressants; wherein fuel efficiency
is improved as compared to fuel efficiency achieved using a
lubricating oil containing a viscosity index improver other than
the at least one propylene-based polymer.
9. The method of claim 8 wherein the lubricating oil is a passenger
vehicle engine oil (PVEO).
10. The method of claim 8 wherein the viscosity index improver
other than the at least one propylene-based polymer comprises an
ethylene-based polymer.
11. A lubricating engine oil having a composition comprising: a
lubricating oil base stock; and a viscosity index improver
comprising at least one propylene-based polymer, said at least one
propylene-based polymer comprising from 60 wt % to 98 wt %
propylene derived units and from 2 wt % to 40 wt % units derived
from one or more other alpha olefins, a weight average molecular
weight (Mw) as measured by GPC of from 100,000 to 500,000, a number
average molecular weight (Mn) as measured by GPC of from 100,000 to
400,000, a molecular weight distribution (MWD=Mw/Mn) of from 1 to
2; and a mole ratio of propylene to one or more other alpha olefins
from 50:50 to 85:15; wherein, in an engine lubricated with said
lubricating engine oil, fuel efficiency is improved as compared to
fuel efficiency achieved using a lubricating engine oil containing
a viscosity index improver other than the at least one
propylene-based polymer.
12. The lubricating engine oil of claim 11 wherein the lubricating
oil base stock comprises a Group I, Group II, Group III, Group IV
or Group V base oil.
13. The lubricating engine oil of claim 11 wherein the wherein the
one or more other alpha olefins comprise butylene.
14. The lubricating engine oil of claim 11 wherein the one or more
other alpha olefins comprise one or more C.sub.4 to C.sub.12
alpha-olefins.
15. The lubricating engine oil of claim 11 wherein the weight
average molecular weight (Mw) as measured by GPC is from 150,000 to
450,000, the number average molecular weight (Mn) as measured by
GPC is from 150,000 to 350,000, the molecular weight distribution
(MWD=Mw/Mn) is from 1.0 to 1.75, and the mole ratio of propylene to
one or more other alpha olefins is from 50:50 to 80:20.
16. The lubricating engine oil of claim 11 wherein the formulated
oil further comprises one or more dispersants.
17. The lubricating engine oil of claim 11 wherein the formulated
oil further comprises one or more pour point depressants.
18. A lubricating engine oil having a composition comprising: from
60 wt % to 98 wt %, based on the total weight of the lubricating
engine oil, of a lubricating oil base stock; from 0.5 wt % to 15 wt
%, based on the total weight of the lubricating engine oil, of a
viscosity index improver comprising at least one propylene-based
polymer, said at least one propylene-based polymer comprising from
60 wt % to 98 wt % propylene derived units and from 2 wt % to 40 wt
% units derived from one or more other alpha olefins, a weight
average molecular weight (Mw) as measured by GPC of from 100,000 to
500,000, a number average molecular weight (Mn) as measured by GPC
of from 100,000 to 400,000, a molecular weight distribution
(MWD=Mw/Mn) of from 1 to 2; and a mole ratio of propylene to one or
more other alpha olefins from 50:50 to 85:15; from 0.1 wt % to 20
wt %, based on the total weight of the lubricating engine oil, of
one or more dispersants; and from 0.0 wt % to 5 wt %, based on the
total weight of the lubricating engine oil, of one or more pour
point depressants; wherein, in an engine lubricated with said
lubricating engine oil, fuel efficiency is improved as compared to
fuel efficiency achieved using a lubricating oil containing a
viscosity index improver other than the at least one
propylene-based polymer.
19. The lubricating engine oil of claim 18 wherein the lubricating
oil is a passenger vehicle engine oil (PVEO).
20. The lubricating engine oil of claim 18 wherein the viscosity
index improver other than the at least one propylene-based polymer
comprises an ethylene-based polymer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/579,342, filed on Dec. 22, 2011; which is
incorporated herein in its entirety by reference.
FIELD
[0002] This disclosure relates to lubricating engines using
formulated lubricating oils to improve engine fuel efficiency.
BACKGROUND
[0003] Fuel efficiency requirements for passenger vehicles are
becoming increasingly more stringent. New legislation in the United
States and European Union within the past few years has set fuel
economy and emissions targets not readily achievable with today's
vehicle and lubricant technology. In order to improve lubricant
fuel economy performance, modification of viscosity is typically
the utilized path.
[0004] The viscosity of lubricating oils is dependent on
temperature. Lubricant oil formulations generally contain viscosity
index ("VI") improving components to modify the rheological
behavior to increase the lubricant viscosity, and promote a more
constant viscosity over the range of temperatures over which the
lubricant is used.
[0005] The viscosity index has been used to measure the rate of
change of viscosity of a fluid in relation to temperature. In
general, the higher the viscosity index, the smaller is the
relative change in viscosity with temperature. The VI improver or
viscosity modifier is used to reduce the temperature dependency of
the viscosity of the lubricant compositions so that the lubricant
compositions can be used over a wide temperature range. In other
words, the VI improvers prevent the lubricant compositions from
becoming too thin at a high temperature, e.g., hot summer
temperatures, and too viscous at a low temperature, e.g., cold
winter temperatures. Some known VI improvers include
polymethacrylates, olefin copolymers, such as ethylene-propylene
copolymers and ethylene-propylene diene-modified copolymers
(EPDMs), and hydrogenated styrenic block copolymers such as
styrene-ethylene/butylene-styrene copolymer (SEBS),
styrene-butadiene copolymers, styrene-isoprene copolymers, and star
polymers.
[0006] In recent years, ethylene/alpha-olefin copolymers have been
widely used as viscosity modifiers, exhibiting the effect of
improving viscosity index for the purpose of decreasing the
temperature dependence of the lubricant's viscosity. See, for
example, U.S. Pat. Nos. 6,589,920; 5,391,617; 7,053,153; and
5,374,700. Lubricating oils lose fluidity at low temperatures
because wax components therein tend to solidify to crystals.
[0007] Despite the advances in lubricant oil formulation
technology, there exists a need for an engine oil lubricant that
effectively improves fuel economy.
SUMMARY
[0008] This disclosure relates in part to a method for improving
fuel efficiency in an engine lubricated with a lubricating oil by
using as the lubricating oil a formulated oil having a composition
comprising:
[0009] a lubricating oil base stock; and
[0010] a viscosity index improver comprising at least one
propylene-based polymer, said at least one propylene-based polymer
comprising from 60 wt % to 98 wt % propylene derived units and from
2 wt % to 40 wt % units derived from one or more other alpha
olefins, a weight average molecular weight (Mw) as measured by GPC
of from 100,000 to 500,000, a number average molecular weight (Mn)
as measured by GPC of from 100,000 to 400,000, a molecular weight
distribution (MWD=Mw/Mn) of from 1 to 2; and a mole ratio of
propylene to one or more other alpha olefins from 50:50 to
85:15;
[0011] wherein fuel efficiency is improved as compared to fuel
efficiency achieved using a lubricating oil containing a viscosity
index improver other than the at least one propylene-based polymer
(i.e., an ethylene propylene VI improver having the same Mw and
shear stability based on D6278).
[0012] This disclosure also relates in part to a method for
improving fuel efficiency in an engine lubricated with a
lubricating oil by using as the lubricating oil a formulated oil
having a composition comprising:
[0013] from 60 wt % to 98 wt %, based on the total weight of the
formulated oil, of a lubricating oil base stock;
[0014] from 0.5 wt % to 15 wt %, based on the total weight of the
formulated oil, of a viscosity index improver comprising at least
one propylene-based polymer, said at least one propylene-based
polymer comprising from 60 wt % to 98 wt % propylene derived units
and from 2 wt % to 40 wt % units derived from one or more other
alpha olefins, a weight average molecular weight (Mw) as measured
by GPC of from 100,000 to 500,000, a number average molecular
weight (Mn) as measured by GPC of from 100,000 to 400,000, a
molecular weight distribution (MWD=Mw/Mn) of from 1 to 2; and a
mole ratio of propylene to one or more other alpha olefins from
50:50 to 85:15;
[0015] from 0.1 wt % to 20 wt %, based on the total weight of the
formulated oil, of one or more dispersants; and
[0016] from 0.0 wt % to 5 wt %, based on the total weight of the
formulated oil, of one or more pour point depressants;
[0017] wherein fuel efficiency is improved as compared to fuel
efficiency achieved using a lubricating oil containing a viscosity
index improver other than the at least one propylene-based polymer
(i.e., an ethylene propylene VI improver having the same Mw and
shear stability based on D6278).
[0018] This disclosure further relates in part to a lubricating
engine oil having a composition comprising:
[0019] a lubricating oil base stock; and
[0020] a viscosity index improver comprising at least one
propylene-based polymer, said at least one propylene-based polymer
comprising from 60 wt % to 98 wt % propylene derived units and from
2 wt % to 40 wt % units derived from one or more other alpha
olefins, a weight average molecular weight (Mw) as measured by GPC
of from 100,000 to 500,000, a number average molecular weight (Mn)
as measured by GPC of from 100,000 to 400,000, a molecular weight
distribution (MWD=Mw/Mn) of from 1 to 2; and a mole ratio of
propylene to one or more other alpha olefins from 50:50 to
85:15;
[0021] wherein, in an engine lubricated with said lubricating
engine oil, fuel efficiency is improved as compared to fuel
efficiency achieved using a lubricating engine oil containing a
viscosity index improver other than the at least one
propylene-based polymer (i.e., an ethylene propylene VI improver
having the same Mw and shear stability based on D6278).
[0022] This disclosure also relates in part to a lubricating engine
oil having a composition comprising:
[0023] from 60 wt % to 98 wt %, based on the total weight of the
lubricating engine oil, of a lubricating oil base stock;
[0024] from 0.5 wt % to 15 wt %, based on the total weight of the
lubricating engine oil, of a viscosity index improver comprising at
least one propylene-based polymer, said at least one
propylene-based polymer comprising from 60 wt % to 98 wt %
propylene derived units and from 2 wt % to 40 wt % units derived
from one or more other alpha olefins, a weight average molecular
weight (Mw) as measured by GPC of from 100,000 to 500,000, a number
average molecular weight (Mn) as measured by GPC of from 100,000 to
400,000, a molecular weight distribution (MWD=Mw/Mn) of from 1 to
2; and a mole ratio of propylene to one or more other alpha olefins
from 50:50 to 85:15;
[0025] from 0.1 wt % to 20 wt %, based on the total weight of the
lubricating engine oil, of one or more dispersants; and
[0026] from 0.0 wt % to 5 wt %, based on the total weight of the
lubricating engine oil, of one or more pour point depressants;
[0027] wherein, in an engine lubricated with said lubricating
engine oil, fuel efficiency is improved as compared to fuel
efficiency achieved using a lubricating oil containing a viscosity
index improver other than the at least one propylene-based polymer
(i.e., an ethylene propylene VI improver having the same Mw and
shear stability based on D6278).
[0028] In accordance with this disclosure, improvements in fuel
economy are obtained without sacrificing engine durability.
[0029] Other objects and advantages of the present disclosure will
become apparent from the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 graphically depicts Kurt Orbahn (ASTM D6278) shear
stability results for the two formulations in the Examples measured
at multiple test lengths.
DETAILED DESCRIPTION
[0031] 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.
[0032] In accordance with this disclosure, improved fuel efficiency
can be attained in an engine lubricated with a lubricating oil by
using as the lubricating oil a formulated oil as described herein.
The lubricating oils of this disclosure are particularly
advantageous as passenger vehicle engine oil (PVEO) products.
Lubricating Oil Base Stocks
[0033] A wide range of lubricating base oils is known in the art.
Lubricating base oils that are useful in the present disclosure are
both natural oils, and synthetic oils, and unconventional oils (or
mixtures thereof) can be used unrefined, refined, or rerefined (the
latter is also known as reclaimed or reprocessed oil). Unrefined
oils are those obtained directly from a natural or synthetic source
and used without added purification. These include shale oil
obtained directly from retorting operations, petroleum oil obtained
directly from primary distillation, and ester oil obtained directly
from an esterification process. Refined oils are similar to the
oils discussed for unrefined oils except refined oils are subjected
to one or more purification steps to improve at least one
lubricating oil property. One skilled in the art is familiar with
many purification processes. These processes include solvent
extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as a feed stock.
[0034] 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 80 to 120 and contain greater than 0.03% sulfur and/or
less than 90% saturates. Group II base stocks have a viscosity
index of between 80 to 120, and contain less than or equal to 0.03%
sulfur and greater than or equal to 90% saturates. Group III stocks
have a viscosity index greater than 120 and contain less than or
equal to 0.03% sulfur and greater than 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 <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 Includes
polyalphaolefins (PAO) and GTL products Group V All other base oil
stocks not included in Groups I, II, III or IV
[0035] 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.
[0036] Group II and/or Group III hydroprocessed or hydrocracked
basestocks, including synthetic oils such as polyalphaolefins,
alkyl aromatics and synthetic esters are also well known basestock
oils.
[0037] 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.
[0038] 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 250
to 3,000, although PAO's may be made in viscosities up to 100 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
C.sub.32 alphaolefins with the C.sub.8 to 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 basestocks 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.
[0039] 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. Nos. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C.sub.14 to C.sub.18
olefins are described in U.S. Pat. No. 4,218,330.
[0040] The hydrocarbyl aromatics can be used as base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least 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 C.sub.6 up to C.sub.60 with a range of C.sub.8 to
C.sub.20 often being preferred. A mixture of hydrocarbyl groups is
often preferred, and up to 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 5% of
the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to 50 cSt are
preferred, with viscosities of approximately 3.4 cSt to 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 2% to 25%,
preferably 4% to 20%, and more preferably 4% to 15%, depending on
the application.
[0041] 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.
[0042] 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 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.
[0043] 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 5 to 10 carbon atoms. These
esters are widely available commercially, for example, the Mobil
P-41 and P-51 esters of ExxonMobil Chemical Company).
[0044] 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.
[0045] 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.
[0046] 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.
[0047] 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 2 mm.sup.2/s to 50 mm.sup.2/s (ASTM D445).
They are further characterized typically as having pour points of
-5.degree. C. to -40.degree. C. or lower (ASTM D97). They are also
characterized typically as having viscosity indices of 80 to 140 or
greater (ASTM D2270).
[0048] 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 10 ppm, and more
typically less than 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 phosphorous and aromatics make this
materially especially suitable for the formulation of low SAP
products.
[0049] 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.
[0050] 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).
[0051] 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) and hydrodewaxed, or
hydroisomerized/cat (and/or solvent) dewaxed base stock(s) and/or
base oil(s) typically have very low sulfur and nitrogen content,
generally containing less than 10 ppm, and more typically less than
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
phosphorous and aromatics make this material especially suitable
for the formulation of low sulfur, sulfated ash, and phosphorus
(low SAP) products.
[0052] Base oils for use in the formulated lubricating oils useful
in the present disclosureare 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.
[0053] The base oil constitutes the major component of the engine
oil lubricant composition of the present disclosure and typically
is present in an amount ranging from 50 to 99 weight percent,
preferably from 70 to 95 weight percent, and more preferably from
85 to 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 2.5 cSt to 12 cSt (or mm.sup.2/s) at 100.degree. C.
and preferably of 2.5 cSt to 9 cSt (or mm.sup.2/s) at 100.degree.
C. Mixtures of synthetic and natural base oils may be used if
desired.
Viscosity Index Improvers
[0054] Viscosity index improvers provide lubricants with high and
low temperature operability. These additives impart shear stability
at elevated temperatures and acceptable viscosity at low
temperatures.
[0055] Propylene-based polymers are used as viscosity index
improvers. These polymers have acceptable properties as viscosity
index improvers with good shear stability and viscosity
characteristics. More particularly, it has been found that
propylene-based polymers having low a-olefin content that, when
used as VI improvers, promote oil thickening, shear stability and
low temperature viscometrics, while lowering the oil pour point.
These propylene-based VI improvers reduce the temperature
dependency of the viscosity of the lubricant compositions so that
the lubricant compositions can be used over a wide temperature
range without solids or gel formations and thereby improve engine
fuel efficiency. Illustrative propylene-based polymers useful as
viscosity index improvers in this disclosure are disclosed in WO
2010/016847, which is incorporated herein in its entirety.
[0056] The propylene-based polymer can be one or more
propylene-alpha-olefin-copolymers, propylene-alpha-olefin-diene
terpolymers, or propylene-diene copolymers. For simplicity and ease
of description, however, the terms "propylene-based polymer" and
"PCP" are used interchangeably herein and refer to one or more
propylene-alpha-olefin-copolymers, propylene-alpha-olefin-diene
terpolymers and propylene-diene copolymers having 60 wt % to 99.7
wt % propylene derived units. Further, for ease of description,
when referring to the PCPs of the present disclosure, one may
interchangeably refer to the PCP being made up of multiple monomers
(i.e., propylene and ethylene) or units derived from monomers
(i.e., propylene-derived units and/or units derived from
alpha-olefins).
[0057] In another embodiment, the propylene-based polymer can be
prepared by polymerizing propylene with ethylene and/or one or more
C.sub.4-C.sub.20 alpha-olefins, or a combination of ethylene and
one or more C.sub.4-C.sub.20 alpha-olefin and one or more dienes.
The one or more dienes can be conjugated or non-conjugated.
Preferably, the one or more dienes are non-conjugated.
[0058] In another embodiment, the propylene-based polymer can be
prepared by polymerizing propylene with one or more dienes. In yet
another embodiment, the propylene-based polymer can be prepared by
polymerizing propylene with ethylene and/or at least one
C.sub.4-C.sub.20 alpha-olefin, or a combination of ethylene and at
least one C.sub.4-C.sub.20 alpha-olefin and one or more dienes. The
one or more dienes can be conjugated or non-conjugated. Preferably,
the one or more dienes are non-conjugated.
[0059] The comonomers can be linear or branched. Preferred linear
comonomers include ethylene or C.sub.4 to C.sub.8 alpha-olefins,
more preferably ethylene, 1-butene, 1-hexene, and 1-octene, even
more preferably ethylene or 1-butene. Preferred branched comonomers
include 4-methyl-1-pentene, 3-methyl-1-pentene, and
3,5,5-trimethyl-1-hexene. In one or more embodiments, the comonomer
can include styrene.
[0060] Illustrative dienes can include but are not limited to
5-ethylidene-2-norbornene (ENB); 1,4-hexadiene;
5-methylene-2-norbornene (MNB); 1,6-octadiene;
5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene;
1,3-cyclopentadiene; 1,4-cyclohexadiene; vinyl norbornene (VNB);
dicyclopendadiene (DCPD), and combinations thereof. Preferably, the
diene is ENB.
[0061] Preferred methods and catalysts for producing the
propylene-based polymers are found in publications U.S.
2004/0236042 and WO 2005/049672 and in U.S. Pat. No. 6,881,800,
which are all incorporated by reference herein. Pyridine amine
complexes, such as those described in WO 2003/040201 are also
useful to produce the propylene-based polymers useful herein. The
catalyst can involve a fluxional complex, which undergoes periodic
intra-molecular re-arrangement so as to provide the desired
interruption of stereoregularity as in U.S. Pat. No. 6,559,262. The
catalyst can be a stereorigid complex with mixed influence on
propylene insertion, see Rieger EP 1 070 087. The catalyst
described in EP 1 614 699 could also be used for the production of
backbones suitable for the invention.
[0062] The propylene-based polymer can have an average propylene
content on a weight percent basis of from 60 wt % to 99.7 wt %,
more preferably from 60 wt % to 99.5 wt %, more preferably from 60
wt % to 98 wt %, more preferably from 60 wt % to 97 wt %, more
preferably from 60 wt % to 95 wt % based on the weight of the
polymer. Other preferred ranges are from 70 wt % to 95 wt %
propylene-derived units, more preferably from 75 wt % to 95 wt %
propylene-derived units, more preferably from 80 wt % to 95 wt %
propylene- derived units, and more preferably from 80 wt % to 90 wt
% propylene-derived units, and more preferably from 80 wt % to 88
wt % propylene based on the weight of the polymer. In one
embodiment, the balance comprises units derived from one or more
alpha-olefins. The one or more alpha-olefins may comprise ethylene,
or one or more C.sub.4-C.sub.20 alpha-olefin or a combination of
ethylene and one or more C.sub.4-C.sub.20 alpha-olefin. In another
embodiment, the one or more alpha-olefins may compromise ethylene,
or one or more C.sub.4-C.sub.12 alpha-olefins or a combination of
ethylene and one or more C.sub.4-C.sub.12 alpha-olefins. In a
preferred embodiment, the one or more alpha-olefins comprises
ethylene. In another embodiment, the one or more alpha-olefins
comprises butene.
[0063] The mole ratio of propylene to the one or more other alpha
olefins (e.g., butylene) can range from 50:50 to 85:15, preferably
from 50:50 to 80:20, and more preferably from 50:50 to 75:25.
[0064] In another embodiment, the balance comprises units derived
from one or more dienes and optionally one or more of the
alpha-olefins described previously. In one or more embodiments
above or elsewhere herein, the alpha-olefin is ethylene, butene,
hexene or octene. In other embodiments, two alpha-olefins are
present, preferably ethylene and one of butene, hexene or
octene.
[0065] In the diene containing embodiments, the propylene-based
polymer comprises 0.2 wt % to 24 wt %, units derived from a
non-conjugated diene based on the weight of the polymer, more
preferably from 0.5 wt % to 12 wt %, more preferably 0.6 wt % to 8
wt %, and more preferably 0.7 wt % to 5 wt %. In other embodiments,
the diene content ranges from 0.2 wt % to 10 wt %, more preferably
from 0.2 to 5 wt %, more preferably from 0.2 wt % to 4 wt %,
preferably from 0.2wt % to 3.5 wt %, preferably from 0.2wt % to 3.0
wt %, and preferably from 0.2 wt % to 2.5 wt % based on the weight
of the polymer. In one or more embodiments above or elsewhere
herein, the propylene-based polymer comprises units derived from
ENB in an amount of from 0.5 to 4 wt %, more preferably from 0.5 to
2.5 wt %, and more preferably from 0.5 to 2.0 wt %.
[0066] In other diene containing embodiments, the propylene-based
polymer preferably comprises propylene-derived units and
diene-derived units in one or more of the ranges described above
with the balance comprising one or more C.sub.2 and/or
C.sub.4-C.sub.20 olefins. In general, this will amount to the
propylene-based polymer preferably comprising from 5 to 40 wt % of
one or more C.sub.2 and/or C.sub.4-C.sub.20 olefins based the
weight of the polymer. When C.sub.2 and/or a C.sub.4-C.sub.20
olefins are present the combined amounts of these olefins in the
polymer is preferably at least 5 wt % and falling within the ranges
described herein. Other preferred ranges for the one or more
alpha-olefins include from 5 wt % to 35 wt %, more preferably from
5 wt % to 30 wt %, more preferably from 5 wt % to 25 wt %, more
preferably from 5 wt % to 20 wt %, more preferably from 5 to 17 wt
% and more preferably from 5 wt % to 16 wt %.
[0067] In one or more embodiments above or elsewhere herein, the
propylene-based polymer can have a Mw of 100,000 to 500,000 g/mole,
more preferably a Mw of 125,000 to 475,000, more preferably a Mw of
150,000 to 450,000, more preferably a Mw of 175,000 to 425,000,
more preferably a Mw of 200,000 to 400,000, more preferably a Mw of
225,000 to 375,000, wherein Mw is determined as described herein.
In one or more embodiments, the propylene-based polymer can have a
Mw ranging from a low of 100,000, 110,000, 120,000, 130,000, or
140,000 to a high of 450,000, 460,000, 470,000, 480,000, or
500,000.
[0068] In one or more embodiments above or elsewhere herein, the
propylene-based polymer can have a Mn of 100,000 to 400,000 g/mole,
more preferably a Mn of 125,000 to 375,000, more preferably a Mn of
150,000 to 350,000, more preferably a Mn of 175,000 to 325,000,
wherein Mn is determined as described herein.
[0069] The molecular weight distribution index (MWD=(Mw/Mn)),
sometimes referred to as a "polydispersity index" (PDI), of the
propylene-based polymer can be 1 to 2. In an embodiment the MWD can
have an upper limit of 2, or 1.95, or 1.9, or 1.85, or 1.8, or
1.75, or 1.7, or 1.65, or 1.6, or 1.55 and a lower limit of 1, or
1.05, or 1.1, or 1.15, or 1.2, or 1.25. In one or more embodiments
above or elsewhere herein, the MWD of the propylene-based polymer
is 1.0 to 1.95, more preferably 1.0 to 1.75, and most preferably
1.0 to 1.5. Techniques for determining the molecular weight (Mn and
Mw) and molecular weight distribution (MWD) can be found in U.S.
Pat. No. 4,540,753 (which is incorporated by reference herein for
purposes of U.S. practices) and references cited therein, in
Macromolecules, 1988, volume 21, p 3360 (Verstrate et al.), which
is herein incorporated by reference for purposes of U.S. practice,
and references cited therein, and in accordance with the procedures
disclosed in U.S. Pat. No. 6,525,157, column 5, lines 1-44, which
patent is hereby incorporated by reference in its entirety.
[0070] In one or more embodiments above or elsewhere herein, the
propylene-based polymer can have a density of 0.85 g/cm.sup.3 to
0.92 g/cm.sup.3, more preferably, 0.87 g/cm.sup.3 to 0.90
g/cm.sup.3 , more preferably 0.88 g/cm.sup.3 to 0.89 g/cm.sup.3 at
room temperature as measured per the ASTM D-1505 test method.
[0071] In one or more embodiments above or elsewhere herein, the
propylene-based polymer can have a melt flow rate (MFR, 2.16 kg
weight @230.degree. C.), equal to or greater than 0.2 g/10 min as
measured according to the ASTM D-1238 test method as modified.
Preferably, the MFR (2.16 kg @230.degree. C.) is from 0.5 g/10 min
to 200 g/10 min and more preferably from 1 g/10 min to 100 g/10
min. In an embodiment, the propylene-based polymer has an MFR upper
limit of 200 g/10 min, 150 g/10 min, 100 g/10 min, 75 g/10 min, 50
g/10 min, 30 g/10 min, 25 g/10 min, or 20 g/10 min and a lower
limit of 0.1 g/10 min, 0.5 g/10 min, 1 g/10 min, 2 g/10 min, 3 g/10
min, 4 g/10 min, 5 g/10 min, 8 g/10 min, or 10 g/10 min. In another
embodiment, the propylene-based polymer has an MFR of 0.5 g/10 min
to 200 g/10 min, preferably from 2 g/10 min to 30 g/10 min, more
preferably from 3g/10 min to 21 g/10 min, more preferably from 5
g/10 min to 30 g/10 min, more preferably 10 g/10 min to 30 g/10
min, more preferably 10 g/10 min to 25 g/10 min, or more preferably
2 g/10 min to 10 g/10 min.
[0072] The propylene-based polymer can have a Mooney viscosity ML
(1+4)@125.degree. C., as determined according to ASTM D 1646, of
less than 100, more preferably less than 75, even more preferably
less than 60, most preferably less than 30. In one or more
embodiments above or elsewhere herein, the Mooney viscosity can
range from a low of 1, 5, 10, or 15 to a high of 30, 60, 75 or
100.
[0073] In one or more embodiments above or elsewhere herein, the
propylene-based polymer can have a heat of fusion (Hf) determined
according to the DSC procedure described herein, which is greater
than or equal to 0.5 Joules per gram (J/g), and is less than or
equal to 80 J/g, preferably less than or equal to 75 J/g,
preferably less than or equal to 70 J/g, more preferably less than
or equal to 60 J/g, more preferably less than or equal to 50 J/g,
more preferably less than or equal to 35 J/g. Also preferably, the
propylene-based polymer has a heat of fusion that is greater than
or equal to 1 J/g, preferably greater than or equal to 5 J/g. In
another embodiment, the propylene-based polymer can have a heat of
fusion (Hf), which is from 0.5 J/g to 75 J/g, preferably from 1
[0074] J/g to 75 J/g, more preferably from 0.5 J/g to 35 J/g.
Preferred propylene-based polymers and compositions can be
characterized in terms of both their melting points (Tm) and heats
of fusion, which properties can be influenced by the presence of
comonomers or steric irregularities that hinder the formation of
crystallites by the polymer chains. In one or more embodiments, the
heat of fusion ranges from a lower limit of 1.0 J/g, or 1.5 J/g, or
3.0 J/g, or 4.0 J/g, or 6.0 J/g, or 7.0 J/g, to an upper limit of
30 J/g, or 35 J/g, or 40 J/g, or 50 J/g, or 60 J/g or 70 J/g, or 75
J/g, or 80 J/g.
[0075] The crystallinity of the propylene-based polymer can also be
expressed in terms of percentage of crystallinity (i.e. %
crystallinity). In certain embodiments above or elsewhere herein,
the propylene-based polymer is substantially amorphous
characterized in that it has 0% crystallinity as determined
according to the DSC procedure described herein. In other
embodiments above or elsewhere herein, the propylene-based polymer
has a % crystallinity of from 0.5% to 40%, preferably 1% to 30%,
more preferably 5% to 25% wherein % crystallinity is determined
according to the DSC procedure described herein. In another
embodiment, the propylene-based polymer preferably has a
crystallinity of less than 40%, preferably 0.25% to 25%, more
preferably from 0.5% to 22%, and most preferably from 0.5% to 20%.
As disclosed above, the thermal energy for the highest order of
polypropylene is estimated at 189 J/g (i.e., 100% crystallinity is
equal to 209 J/g.).
[0076] In addition to this level of crystallinity, the
propylene-based polymer preferably has a single broad melting
transition. However, the propylene-based polymer can show secondary
melting peaks adjacent to the principal peak, but for purposes
herein, such secondary melting peaks are considered together as a
single melting point, with the highest of these peaks (relative to
baseline as described herein) being considered the melting point of
the propylene-based polymer.
[0077] Heat of fusion, % crystallinity and melting temperature of
the propylene-based polymer can be determined, for example by a
Differential Scanning calorimetry (DSC) as described n WO
2010/016847, supra.
[0078] In one or more embodiments, the propylene-based polymer can
be blended with other polymeric viscosity index modifiers, such as
polybutenes, polymers of styrene with butadiene or isoprene that
may optionally be hydrogenated or a combination of butadiene or
isoprene, ester based viscosity index modifiers such as esters of
styrene/maleic anhydride polymers, esters of styrene/maleic
anhydride/acrylate terpolymers, and polymethacrylates. Examples for
such viscosity index modifiers for such blends include acrylate-or
methacrylate-containing copolymers or copolymers of styrene and an
ester of an unsaturated carboxylic acid such as styrene/maleic
ester (typically prepared by esterification of a styrene/maleic
anhydride copolymer).
[0079] In one or more embodiments, the propylene-based polymer can
itself be a blend of discrete random propylene-based polymers. Such
blends can include ethylene-based polymers and propylene-based
polymers, or at least one of each such ethylene-based polymers and
propylene-based polymers. The number of propylene-based polymers
can be three or less, more preferably two or less. In embodiments
where the propylene-based polymer is a blend of discrete random
propylene-based polymers, it may further be blended with other
polymeric viscosity index modifiers, such as polybutenes, polymers
of styrene with butadiene or isoprene or a combination of butadiene
or isoprene, ester based viscosity index modifiers such as esters
of styrene/maleic anhydride polymers, esters of styrene/maleic
anhydride/acrylate terpolymers, and polymethacrylates. Examples for
such viscosity index modifiers for such blends include acrylate-or
methacrylate-containing copolymers or copolymers of styrene and an
ester of an unsaturated carboxylic acid such as styrene/maleic
ester (typically prepared by esterification of a styrene/maleic
anhydride copolymer).
[0080] In one or more embodiments above or elsewhere herein, the
propylene-based polymer can include a blend of two propylene-based
polymers differing in the olefin content, the diene content, or
both.
[0081] In another embodiment, the propylene-based polymers can
include copolymers prepared according to the procedures in WO
02/36651. Likewise, the propylene-based polymer can include
polymers consistent with those described in WO 2003/040201, WO
2003/040202, WO 2003/040095, WO 2003/040201, WO 2003/040233, and/or
WO 2003/040442. Additionally, the propylene-based polymer can
include polymers consistent with those described in EP 1 233 191,
and U.S. Pat. No. 6,525,157, along with suitable propylene homo-
and copolymers described in U.S. Pat. No. 6,770,713 and U.S. Patent
Application Publication 2005/215964, all of which are incorporated
by reference. The propylene-based polymer can also include one or
more polymers consistent with those described in EP 1 614 699 or EP
1 017 729.
[0082] In one or more embodiments, the propylene-based polymer can
be grafted (i.e. "functionalized") using one or more grafting
monomers as described in WO 2010/016847, supra. As used herein, the
term "grafting" denotes covalent bonding of the grafting monomer to
a polymer chain of the propylene-based polymer. The grafted
propylene-based polymer can be prepared using conventional
techniques.
Other Additives
[0083] The formulated lubricating oil useful in the present
disclosure may additionally contain one or more of the other
commonly used lubricating oil performance additives including but
not limited to dispersants, detergents, pour point depressants
(PPDs), corrosion inhibitors, rust inhibitors, metal deactivators,
other anti-wear agents and/or extreme pressure additives,
anti-seizure agents, wax modifiers, viscosity modifiers, fluid-loss
additives, seal compatibility agents, friction modifiers, lubricity
agents, anti-staining agents, chromophoric agents, defoamants,
demulsifiers, emulsifiers, densifiers, wetting agents, gelling
agents, tackiness agents, colorants, and others. For a review of
many commonly used additives, see Klamann in Lubricants and Related
Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN 0-89573-177-0.
Reference is also made to "Lubricant Additives" by M. W. Ranney,
published by Noyes Data Corporation of Parkridge, N.J. (1973).
[0084] The types and quantities of performance additives used in
combination with the instant disclosurein lubricant compositions
are not limited by the examples shown herein as illustrations.
Dispersants
[0085] During engine operation, oil-insoluble oxidation byproducts
are produced.
[0086] Dispersants help keep these byproducts in solution, thus
diminishing their deposition on metal surfaces. Dispersants used in
the formulation of the lubricating oil may be ashless or
ash-forming in nature. Preferably, the dispersant is ashless. So
called ashless dispersants are organic materials that form
substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0087] 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.
[0088] Chemically, many dispersants may be characterized as
phenates, sulfonates, sulfurized phenates, salicylates,
naphthenates, stearates, carbamates, thiocarbamates, phosphorus
derivatives. A particularly useful class of dispersants are the
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; 3,215,707; 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.
[0089] 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.
[0090] 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 1:1 to 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.
[0091] 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.
[0092] 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.
[0093] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500. 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 0.1 to 5 moles of boron per mole of dispersant reaction
product.
[0094] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Patent 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.
[0095] 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 HN(R).sub.2 group-containing reactants.
[0096] 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.
[0097] 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
500 to 5000 or a mixture of such hydrocarbylene groups. Other
preferred dispersants include succinic acid-esters and amides,
alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components. Such additives may be
used in an amount of 0.1 to 20 weight percent, preferably 0.5 to 8
weight percent.
Pour Point Depressants (PPDs)
[0098] 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 0.01 to 5 weight percent, preferably 0.01 to
1.5 weight percent.
Detergent Additives
[0099] Illustrative detergent 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 acid,
carboxylic acid, phosphorous acid, phenol, or mixtures thereof. The
counterion is typically an alkaline earth or alkali metal.
[0100] 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.
[0101] 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.
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. 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.
[0102] Metal salts of carboxylic acids are also useful as
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 30 carbon atoms, n is an
integer from 1 to 4, and
[0103] M is an alkaline earth metal. Preferred R groups are alkyl
chains of at least C.sub.11, preferably C.sub.13 or greater. R may
be optionally substituted with substituents that do not interfere
with the detergent's function. M is preferably, calcium, magnesium,
or barium. More preferably, M is calcium.
[0104] 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.
[0105] Alkaline earth metal phosphates are also used as detergents
and are known in the art.
[0106] 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.
[0107] Preferred detergents include calcium phenates, calcium
sulfonates, calcium salicylates, magnesium phenates, magnesium
sulfonates, magnesium salicylates and other related components
(including borated detergents), and mixtures thereof. Preferred
detergents include magnesium sulfonate and calcium salicylate.
[0108] The detergent mixture concentration in the lubricating oils
of this disclosure can range from 1.0 to 6.0 weight percent,
preferably 2.0 to 5.0 weight percent, and more preferably from 2.0
weight percent to 4.0 weight percent, based on the total weight of
the lubricating oil.
Antioxidants
[0109] 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.
[0110] 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).
[0111] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R.sup.8R.sup.9R.sup.10N
where R.sup.8 is an aliphatic, aromatic or substituted aromatic
group, R.sup.9 is an aromatic or a substituted aromatic group, and
R.sup.10 is H, alkyl, aryl or R.sup.11S(O).sub.xR.sup.12 where
R.sup.11 is an alkylene, alkenylene, or aralkylene group, R.sup.12
is a higher alkyl group, or an alkenyl, aryl, or alkaryl group, and
x is 0, 1 or 2. The aliphatic group R.sup.8 may contain from 1 to
20 carbon atoms, and preferably contains from 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.
[0112] Typical aromatic amines antioxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 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.
[0113] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0114] 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 0.01 to 5 weight percent, preferably 0.01 to 1.5 weight
percent, more preferably zero to less than 1.5 weight percent, most
preferably zero.
Antiwear Additives
[0115] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) is an essential component of
the lubricating oils of this disclosure. ZDDP can be primary,
secondary 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.
[0116] 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".
[0117] The ZDDP is typically used in amounts of from 0.4 weight
percent to 1.2 weight percent, preferably from 0.5 weight percent
to 1.0 weight percent, and more preferably from 0.6 weight percent
to 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 0.6 to 1.0 weight percent of the total weight of the
lubricating oil.
Seal Compatibility Agents
[0118] 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 0.01
to 3 weight percent, preferably 0.01 to 2 weight percent.
Antifoam Agents
[0119] 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.
Friction Modifiers
[0120] 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. Friction modifiers may include
metal-containing compounds or materials as well as ashless
compounds or materials, or mixtures thereof. Metal-containing
friction modifiers may include metal salts or metalligand complexes
where the metals may include alkali, alkaline earth, or transition
group metals. Such metal-containing friction modifiers may also
have low-ash characteristics. Transition metals may include Mo, Sb,
Sn, Fe, Cu, Zn, and others. Ligands may include hydrocarbyl
derivative of alcohols, polyols, glycerols, partial ester
glycerols, thiols, carboxylates, carbamates, thiocarbamates,
dithiocarbamates, phosphates, thiophosphates, dithiophosphates,
amides, imides, amines, thiazoles, thiadiazoles, dithiazoles,
diazoles, triazoles, and other polar molecular functional groups
containing effective amounts of O, N, S, or P, individually or in
combination. In particular, Mo-containing compounds can be
particularly effective such as for example Mo-dithiocarbamates,
Mo(DTC), Mo-dithiophosphates, Mo(DTP), Mo-amines, Mo(Am),
Mo-alcoholates, Mo-alcohol-amides, etc. See U.S. Pat. Nos.
5,824,627, 6,232,276, 6,153,564, 6,143,701, 6,110,878, 5,837,657,
6,010,987, 5,906,968, 6,734,150, 6,730,638, 6,689,725, 6,569,820;
WO 99/66013; WO 99/47629; and WO 98/26030.
[0121] Ashless friction modifiers may also include lubricant
materials that contain effective amounts of polar groups, for
example, hydroxyl-containing hydrocarbyl base oils, glycerides,
partial glycerides, glyceride derivatives, and the like. Polar
groups in friction modifiers may include hydrocarbyl groups
containing effective amounts of O, N, S, or P, individually or in
combination. Other friction modifiers that may be particularly
effective include, for example, salts (both ash-containing and
ashless derivatives) of fatty acids, fatty alcohols, fatty amides,
fatty esters, hydroxyl-containing carboxylates, and comparable
synthetic long-chain hydrocarbyl acids, alcohols, amides, esters,
hydroxy carboxylates, and the like. In some instances fatty organic
acids, fatty amines, and sulfurized fatty acids may be used as
suitable friction modifiers.
[0122] Useful concentrations of friction modifiers may range from
0.01 weight percent to 10-15 weight percent or more, often with a
preferred range of 0.1 weight percent to 5 weight percent.
Concentrations of molybdenum-containing materials are often
described in terms of Mo metal concentration. Advantageous
concentrations of Mo may range from 10 ppm to 3000 ppm or more, and
often with a preferred range of 20-2000 ppm, and in some instances
a more preferred range of 30-1000 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.
[0123] 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 A below.
[0124] 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 diluent.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned in this specification, 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 A Typical Amounts of Other Lubricating Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Dispersant 0.1-20 0.1-8 Friction Modifier 0.01-5
0.01-1.5 Antioxidant 0.1-5 0.1-2 Pour Point Depressant 0.0-5
0.01-1.5 (PPD) Anti-foam Agent 0.001-3 0.001-0.15 Viscosity Index
Improver 0.0-2 0.0-1 (solid polymer basis)
[0125] 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.
[0126] In an embodiment, improved fuel efficiency can be attained,
while wear protection is maintained or improved, in an engine
lubricated with a lubricating oil by using as the lubricating oil a
formulated oil as described herein. Improved engine fuel efficiency
can be achieved without sacrificing engine durability. The engine
oil lubricants of this disclosure can effectively improve fuel
economy while providing desired antiwear performance over a wide
temperature range. The lubricating oils of this disclosure are
particularly advantageous as passenger vehicle engine oil (PVEO)
products.
[0127] The following non-limiting examples are provided to
illustrate the disclosure.
EXAMPLES
[0128] One SAE 5W-20 engine oil was blended with VL1151J (The
Lubrizol Corporation) viscosity index (VI) improver and another SAE
5W-20 engine oil was blended with Paratone 8451 (Chevron Oronite
Company) VI improver. Both of the VI improvers are olefin
copolymers. VL1151J uses propylene and butylene as the olefins
which are polymerized while Paratone 8451 uses ethylene and
propylene as the olefins which are polymerized. VL1151J was used as
a concentrate containing 11.5 wt % solid polymer in a Group II base
oil, and Paratone 8451 was used as a concentrate containing 6.3 wt
% solid polymer in a Group I base oil. Both of these oils meet the
requirements for an SAE 5W-20 viscosity grade as defined by SAE
J300. The formulation containing VL1151J has a slightly higher HTHS
viscosity. This is significant because fuel economy performance is
inversely correlated with HTHS viscosity. Table 1 compares the
physical properties of two SAE 5W-20 engine oils.
TABLE-US-00003 TABLE 1 10070319 10072926 Additives, % 9.86 9.86
VL1151J VII, % 4.5 0 Paratone 8451 VII, % 0 4.7 Basestocks, % 85.54
85.34 D445 KV at 100 C. mm2/s 7.88 7.78 D4683 HTHS Visc at 150 C.
cP 2.65 2.59 D5293-7 CCS @ -35 C. mPa s 6850 6350
[0129] FIG. 1 provides Kurt Orbahn (ASTM D6278) shear stability
results for the above two formulations measured at multiple test
lengths. The Kurt Orbahn shear stability results are equivalent for
the formulations blended with the two different VI improvers at 0,
5, 10, and 30 test cycles.
[0130] Sequence VID (ASTM D7589) fuel economy testing was conducted
for the two 5W-20 formulations blended with the VL1151J and
Paratone 8451 VI improvers. Table 2 provides the Sequence VID fuel
economy testing results. The results show the superior fuel economy
benefits obtained using the VL1151J VI improvers. Reduced fuel
consumption occurred in Sequence VID stages 1, 3, 4, 5 and for the
overall test (reported after FEI 1 measurement). The precision for
the FEI 1 measurement is 0.13%. Thus, the benefit for the VL1151J
VI improver was 3.4 standard deviation units above the Paratone VI
improver. This benefit is statistically significant at a greater
than 95% confidence level.
TABLE-US-00004 TABLE 2 10070319 10072926 VI Improver VL1151J
Paratone 8451 Stage 1 1.54 1.25 Stage 2 2.71 2.70 Stage 3 0.82 0.54
Stage 4 0.61 -0.13 Stage 5 5.66 5.20 Stage 6 0.30 0.65 FEI 1
Initial 1.35 0.96 Severity Adjustment -0.04 -0.10 Final FEI 1 1.31
0.86
[0131] Table 3 compares Gel Permeation Chromatography
characterization of the VL1151J and Paratone 8451 VI improvers. Of
note is the very similar weight average molecular weight for the
two VI improvers. However, the VL1151J VI improver has a much lower
polydispersity index or molecular weight distribution which results
in improved fuel economy performance.
TABLE-US-00005 TABLE 3 Polymer Paratone Characterization VL1151J
8451 Mw 312,000 300,200 Mn 265,000 194,100 PDI 1.2 1.5
[0132] 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.
[0133] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0134] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *
References