U.S. patent application number 13/664572 was filed with the patent office on 2013-06-06 for lubricants with improved low-temperature fuel economy.
This patent application is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. The applicant listed for this patent is EXXONMOBIL RESEARCH AND ENGINEERING. Invention is credited to David Joseph Baillargeon, Douglas Edward Deckman, Steven Michael Jetter, Kevin John Kelly, Kristen Amanda Lyon, Donald J. Mattran, Jessica Lee Prince, Anne M. Shough.
Application Number | 20130143782 13/664572 |
Document ID | / |
Family ID | 47258088 |
Filed Date | 2013-06-06 |
United States Patent
Application |
20130143782 |
Kind Code |
A1 |
Baillargeon; David Joseph ;
et al. |
June 6, 2013 |
LUBRICANTS WITH IMPROVED LOW-TEMPERATURE FUEL ECONOMY
Abstract
Lubricating oil compositions, formulated to a preselected
viscosity grade that demonstrate stay-in-grade capability in a
diesel injector shear stability test, are provided. The
compositions comprise a major amount of a base oil of lubricating
viscosity and a minor amount of (i) a viscosity modifier (VM) or
mixtures thereof having a low shear stability index (SSI) and (ii)
a VM or mixtures thereof having an SSI greater than that of the VM
from (i).
Inventors: |
Baillargeon; David Joseph;
(Cherry Hill, NJ) ; Jetter; Steven Michael;
(Hightstown, NJ) ; Shough; Anne M.; (New Castle,
DE) ; Deckman; Douglas Edward; (Mullica Hill, NJ)
; Kelly; Kevin John; (Mullica Hill, NJ) ; Lyon;
Kristen Amanda; (West Deptford, NJ) ; Mattran; Donald
J.; (Houston, TX) ; Prince; Jessica Lee;
(Deptford, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EXXONMOBIL RESEARCH AND ENGINEERING; |
Annandale |
NJ |
US |
|
|
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
47258088 |
Appl. No.: |
13/664572 |
Filed: |
October 31, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61554140 |
Nov 1, 2011 |
|
|
|
Current U.S.
Class: |
508/459 ;
508/110; 585/10; 585/11 |
Current CPC
Class: |
C10N 2030/54 20200501;
C10N 2030/68 20200501; C10M 169/04 20130101; C10M 2203/1025
20130101; C10M 1/00 20130101; C10N 2040/255 20200501; C10M
2203/1045 20130101; C10N 2040/25 20130101; C10M 2205/04 20130101;
C10M 157/00 20130101; C10M 2205/223 20130101; C10M 2205/0285
20130101; C10N 2030/02 20130101; C10N 2040/253 20200501; C10M
2207/2805 20130101; C10M 2205/04 20130101; C10M 2205/06 20130101;
C10M 2203/1025 20130101; C10N 2020/02 20130101; C10M 2203/1025
20130101; C10N 2020/02 20130101 |
Class at
Publication: |
508/459 ; 585/10;
585/11; 508/110 |
International
Class: |
C10M 107/12 20060101
C10M107/12 |
Claims
1. A lubricating oil composition formulated to a preselected SAE
engine oil viscosity, said composition comprising: (a) a major
amount of a base oil of lubricating viscosity; and (b) a minor
amount of (i) a viscosity modifier (VM) or mixtures thereof having
a low shear stability index (SSI), and (ii) a VM or mixtures
thereof having an SSI greater than the VM from (i); (c) wherein the
sheared kinematic viscosity at 100.degree. C. of the composition
after 90 cycles in the diesel injector shear stability test (ASTM
D7109) is equal to or greater than the minimum viscosity for the
preselected grade before shearing; and (d) wherein the sheared
viscosity (c) is less than 25% lower relative to the unsheared
composition viscosity.
2. The composition of claim 1 wherein the VM's of (i) therein have
an SSI in the range of 4 to 12.
3. The composition of claim 1 wherein the VMs of (ii) have an SSI
in the range of 8 to 65 or higher.
4. The composition of claim 2 wherein the VM weight ratio of VM(ii)
to VM(i) is in the range of 0.01 to 1.5.
5. The composition of claim 3 wherein the VM weight ratio of VM(ii)
to VM(i) is in the range of 0.05 to 1.
6. The composition of claim 4 wherein the total amount of VM(i) and
VM(ii) comprises from 0.1 wt % to 2.5 wt % of the total weight of
the composition.
7. The composition of claim 5 wherein the total amount of VM(i) and
VM(ii) comprises from 0.1 wt % to 2.5 wt % of the total weight of
the composition.
8. The composition of claim 1 wherein the VMs are selected from
vinylaromatic-diolefin copolymers.
9. The composition of claim 1 wherein the VMs are selected from
olefin copolymers and vinylaromatic-diolefin copolymers.
10. The composition of claim 1 wherein the base oil comprises one
or more base oils selected from Group III and Group IV oils and
mixtures thereof.
11. The composition of claim 1 comprising one or more lubricant
additives, selected from oxidation inhibitors, dispersants,
detergents, corrosion inhibitors, metal deactivators, antiwear
additives, extreme pressure additives, pour point depressants, seal
compatibility agents, friction modifiers, defoamants and dyes.
12. In the method of lubricating an internal combustion engine by
supplying a lubricating oil composition to the engine, the
improvement comprising supplying an SAE multigraded lubricating oil
composition to the engine, said oil composition comprising any of
the compositions of claims 1 to 11, thereby enhancing the fuel
efficiency of the engine while providing stay-in-grade viscosity
retention for stable engine performance.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/554,140 filed on Nov. 1, 2011, which is
incorporated herein in its entirety by reference.
FIELD
[0002] The present disclosure is directed to lubricating oil
compositions for use in crankcase engine oils. More specifically,
the disclosure is directed to crankcase engine oils that are
effective in achieving improved low temperature fuel economy (FE)
while simultaneously having high temperature, high shear viscosity
(HTHS).
BACKGROUND
[0003] Lubricating oil compositions for use as crankcase engine
oils comprise a major amount of a base oil and minor amounts of
additives selected to enhance the performance characteristics of
the base oil. For example, an important property of a lubricating
oil is its ability to maintain a lubricating film between moving
mechanical parts over a range of temperatures. This ability is a
function of the viscometric properties of the lubricating oil.
Typically, oil soluble, high molecular weight polymers are used to
improve the viscometric performance of engine oil compositions.
These materials commonly are referred to as viscosity modifiers
(VM), and they function to reduce a decrease in the lubricating
composition's viscosity upon an increase in temperature and the
converse upon a decrease in temperature. Indeed, VMs are used to
formulate lubricating compositions that meet the multigrade
viscosity classification system of the Society of Automotive
Engineers (SAE J300 specification) and are numerically numbered
such as SAE 0W-20, 0W-30, 5W-30, 10W-30, 10W-40 and the like. In
this system, the first number is related to a low temperature
viscosity characteristic, and the second number, to high
temperature viscosity characteristics.
[0004] It is well known that engine oils having low viscosities at
low temperatures have desirable low temperature fuel economy (FE)
performance. Unfortunately, lowering an engine oil viscosity can
detrimentally affect high temperature performance. For example, a
lower oil viscosity can result in lower film thickness as measured
by high temperature, high shear (HTHS) viscosity, which is
undesirable. Also, the use of VMs to improve the high temperature
viscosity of the lubricating composition generally has an adverse
affect on the low temperature properties.
[0005] One object of the present disclosure is to provide
lubricating oil compositions that have improved low temperature FE
performance.
[0006] Another object of the disclosure is to provide lubricating
compositions for both gasoline and diesel engines that are
effective over a broad range of lubricant viscosity and that they
stay in grade as demonstrated by a diesel injector shear stability
test.
[0007] Other objectives will become apparent from the detailed
description that follows.
SUMMARY
[0008] One embodiment of the disclosure provides a lubricating oil
composition formulated to a preselected SAE engine oil viscosity
grade, said composition comprising: [0009] (a) a major amount of a
base oil of lubricating viscosity; and [0010] (b) a minor amount of
[0011] (i) a viscosity modifier (VM) or mixtures thereof having a
low shear stability index (SSI), and [0012] (ii) a VM or mixtures
thereof having an SSI greater than the VM from (i); [0013] (c)
wherein the sheared kinematic viscosity at 100.degree. C. of the
composition after 90 cycles in the diesel injector shear stability
test (ASTM D7109) is equal to or greater than the minimum viscosity
for the preselected grade before shearing; and [0014] (d) wherein
the sheared viscosity (c) is less than 20% lower relative to the
unsheared composition viscosity.
[0015] In a preferred embodiment of the disclosure, the weight
ratios of VM (ii) to VM (i) above, VM(ii)/VM(i), is in the range of
from 0.01 to 1.5.
[0016] Another embodiment of the disclosure provides a method for
lubricating an internal combustion engine comprising supplying the
engine crankcase with the above lubricant composition whereby the
composition is applied to the engine during operating
conditions.
[0017] Other embodiments will become apparent from the detailed
description and examples which follow.
DETAILED DESCRIPTION
[0018] 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.
[0019] It has now been found that an engine oil lubricant
composition comprising a major amount of base oil and an effective
amount of a mixture of high-SSI and low-SSI polymeric viscosity
modifiers provides improved fuel efficiency while providing
stay-in-grade viscosity retention for stable engine
performance.
[0020] 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.
[0021] Groups I, II, III, IV and V are broad categories of base oil
stocks developed and defined by the American Petroleum Institute
(API Publication 1509; www.API.org) to create guidelines for
lubricant base oils. Group I base stocks generally have a viscosity
index of between 80 to 120 and contain greater than 0.03% sulfur
and/or less than 90% saturates. Group II base stocks generally 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 generally 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.
Base Oil Properties
TABLE-US-00001 [0022] Saturates Sulfur Viscosity Index Group I
<90 &/or >0.03% & .gtoreq.80 & < 120 Group II
.gtoreq.90 & .ltoreq.0.03% & .gtoreq.80 & < 120
Group III .gtoreq.90 & .ltoreq.0.03% & .gtoreq.120 Group IV
Includes polyalphaolefins (PAO) Group V All other base oil stocks
not included in Groups I, II, III, or IV
[0023] 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.
[0024] Group II and/or Group II hydroprocessed or hydrocracked
basestocks, including synthetic oils such as polyalphaolefins,
alkyl aromatics and synthetic esters are also well known basestock
oils.
[0025] 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.
[0026] 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.
[0027] 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 U.S. Pat. No. 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.
[0028] 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.
[0029] 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.
[0030] 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 dipenta-erythritol) 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, paimitic
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.
[0031] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipenta-erythritol 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).
[0032] 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.
[0033] 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 or Fischer-Tropsch processes, and
mixtures of such base stocks.
[0034] The lubricating oil compositions of the disclosure comprise
a major amount of a base oil of lubricating viscosity. In general,
the base oil will comprise greater than 50 wt % based on the total
weight of the composition, and typically, from 50 wt % to 99 wt %,
and preferably, from 70 wt % to 95 wt %. 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. For example, suitable base oils may
comprise one or more base stocks selected from Group III, Group IV
and mixtures of Group III and Group IV base stocks. These base
stock groups are defined in the American Petroleum Institute
Publication "Engine Oil Licensing and Certification System",
Fourteenth Edition, December 1966, Addendum I, December 1998. The
base stock typically will have a kinematic viscosity (KV) at
100.degree. C., as determined by ASTM D445, of 1 cSt to 12 cSt (or
mm.sup.2/s) and preferably 1.5 cSt to 9 cSt (or mm.sup.2/s).
Mixtures of synthetic and natural base oils may be used if
desired.
[0035] The compositions of the disclosure include a minor, but
effective, amount of a mixture of VMs comprising (i) a VM or
mixture of VMs, each having an SSI of 12 or less and (ii) a VM or
mixture of VMs, each having an SSI greater than the VM of (i). In
general, the VMs of (i) above will have SSIs in the range of 4 to
12, and preferably from 4 to 10, while the VMs of (ii) above will
have SSIs in the range of 8 or higher, preferably from 12 to 65,
and may include embodiments of VMs with SSIs of 24 or higher, 35 or
higher, 45 or higher, and 50 or higher, for example.
[0036] The amount of the mixture of VMs (i) and (ii) in the
composition may range from 0.01 wt % to 4 wt %, preferably from
0.01 wt % to 2 wt %, and more preferably from 0.1 wt % to 2 wt % on
a solid polymer basis, based on the total weight of the
composition.
[0037] Importantly, the weight ratio of VM(ii)/VM(i) is from 0.01
to 1.5, preferably 0.05 to 1, and more preferably 0.05 to 0.8, and
in further instances in the range of 0.1 to 0.8.
[0038] For the purposes of this disclosure, the VMs are selected
from oil soluble or oil dispersible polymers typically used in
crankcase lubricant compositions to improve the viscometric
performance of the engine oil. Viscosity modifiers (VMs) are also
known as VI improvers, viscosity index improvers, viscosity
improvers, and thickeners.
[0039] Suitable viscosity index improvers include high molecular
weight hydrocarbons, polyesters and viscosity index improver
dispersants that function as both a viscosity index improver and a
dispersant. Typical molecular weights of these polymers are between
10,000 to 1,000,000, more typically 20,000 to 500,000, and even
more typically between 50,000 and 200,000.
[0040] Examples of suitable viscosity index improvers are linear or
star-shaped polymers and copolymers of methacrylate, butadiene,
olefins, or alkylated styrenes. Polyisobutylene is a commonly used
viscosity index improver. Another suitable viscosity index improver
is polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity index improvers
include copolymers of ethylene and propylene, copolymers of olefins
and alpha-olefins, 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.
[0041] Olefin copolymers, are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921", "PARATONE.RTM. 8941", "PARATONE.RTM.
8451", "PARATONE.RTM. 68530"); 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". Polyisoprene polymers are
commercially available from Infineum International Limited, e.g.
under the trade designation "SV200"; diene-styrene copolymers are
commercially available from Infineum International Limited, e.g.
under the trade designation "SV260". Other examples include
"SV140", "SV150", "SV250", "SV270", and "SV300".
[0042] The compositions of the disclosure are formulated to meet
any one of the SAE viscosity grades for engine oils such as xW-50,
xW-40, xW-30, xW-20 and the like, where x==15, 10, 5, or 0 and the
like, and includes higher viscosity grades and lower viscosity
grades, and includes grades not classifiable by SAE J300.
[0043] Compositions according to the disclosure are characterized
by the fact that for any preselected viscosity grade, the sheared
kinematic viscosity at 10.degree. C. after 90 cycles in the diesel
injector sheared stability test ASTM D) 7109 is equal to or greater
than the minimum viscosity (at 100.degree. C.) for the preselected
grade before shearing. Retention of kinematic viscosity at
100.degree. C. within a single SAE viscosity grade classification
by a fresh oil and its sheared version is evidence of an oil's
stay-in-grade capability.
[0044] The compositions of the disclosure display stay-in-grade
capability, and display a viscosity loss measured at 100.degree. C.
after 90 cycles in the diesel injector shear stability test of less
than 25%, preferably less than 20%, more preferably less than 18%,
and in some instances less than 14%.
[0045] The compositions of the present disclosure may also include
other additives to improve or impart desired properties of the
fully formulated compositions. These additives may be selected from
conventional types of lubricant additives. Such additives include
oxidation inhibitors, dispersants, detergents, corrosion
inhibitors, metal deactivators, antiwear additives, extreme
pressure additives, pour point depressants, seal compatibility
agents, friction modifiers, defoamants and dyes. Each of these
types of additives may be used in amounts commonly used in
lubricant compositions. In general, on an active ingredient basis,
the various lubricant additives will comprise from 0.5 wt % to 25
wt %, and preferably, from 2 wt % to 15 wt % based on the total
weight of the composition.
[0046] While there are many different types of antiwear additives,
for several decades the principal antiwear additive for internal
combustion engine crankcase oils is a metal alkylthiophosphate and
more particularly a metal dialkyldithiophosphate in which the metal
constituent is zinc, or zinc dialkyldithiophosphate (ZDDP). 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. The ZDDP is typically used in amounts
of from 0.4 to 1.4 wt % of the total lubricant oil composition,
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 wt % of the total lubricant composition.
[0047] 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".
[0048] Additional types of antiwear additives are effectively used
in lubricant compositions and include, for example, metal-free,
ashless, low-phosphorous, non-phosphorous, oligomeric, polymeric,
zinc-containing, metal-containing (other than zinc),
multi-functional chemical combinations of these, and other antiwear
additives. All antiwear additives above, and the like, may be used
individually and in combinations in lubricant compositions.
[0049] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
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.
[0050] 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.
[0051] Chemically, many dispersants may be characterized as
phenates, sulfonates, sulfurized phenates, salicylates,
naphthenates, stearates, carbamates, thiocarbamates, phosphorous
derivatives. A particularly useful class of dispersants are the
alkenylsuccinic derivatives, typically produced by the reaction of
a long chain substituted alkenyl succinic compound, usually a
substituted succinic anhydride, with a polyhydroxy or polyamino
compound. The long chain 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.
[0052] Hydrocarbyl-substituted succinic acid compounds are popular
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.
[0053] Succinimides are formed by the condensation reaction between
alkenyl succinic anhydrides and amines. Molar ratios can vary
depending on the poly-amine. For example, the molar ratio of
alkenyl 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 Pat. No. 1,094,044.
[0054] Succinate esters are formed by the condensation reaction
between alkenyl succinic anhydrides and alcohols or polyols. Molar
ratios can vary depending on the alcohol or polyol used. For
example, the condensation product of an alkenyl succinic anhydride
and pentaerythritol is a useful dispersant.
[0055] Succinate ester amides are formed by condensation reaction
between alkenyl succinic anhydrides and alkanol amines. For
example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenyipolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0056] The molecular weight of the alkenyl 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, and boron compounds such as borate esters or highly
borated dispersants. The dispersants can be borated with from 0.1
to 5 moles of boron per mole of dispersant reaction product.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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 wt %, preferably 0.5 to 8 wt %.
[0061] Detergents are commonly used in lubricating compositions. 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.
[0062] Salts that contain a substantially stoichiometric 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.
[0063] It is desirable for at least some detergent to be overbased.
Overbased detergents help neutralize acidic impurities produced by
the combustion process and become entrapped in the oil. Typically,
the overbased material has a ratio of metallic ion to anionic
portion of the detergent of 1.05:1 to 50:1 on an equivalent basis.
More preferably, the ratio is from 4:1 to 25:1. The resulting
detergent is an overbased detergent that will typically have a TBN
of 150 or higher, often 250 to 450 or more. Preferably, the
overbasing cation is sodium, calcium, or magnesium. A mixture of
detergents of differing TBN can be used in the present
disclosure.
[0064] Preferred detergents include the alkali or alkaline earth
metal salts of sulfonates, phenates, carboxylates, phosphates, and
salicylates.
[0065] Sulfonates may be prepared from sulfonic acids that are
typically obtained by sulfonation of alkyl substituted aromatic
hydrocarbons. Hydrocarbon examples include those obtained by
alkylating benzene, toluene, xylene, naphthalene, biphenyl and
their halogenated derivatives (chlorobenzene, chlorotoluene, and
chloronaphthalene, for example). The alkylating agents typically
have 3 to 70 carbon atoms. The alkaryl sulfonates typically contain
9 to 80 carbon or more carbon atoms, more typically from 6 to 60
carbon atoms.
[0066] Klamann in "Lubricants and Related Products", op cit
discloses a number of overbased metal salts of various sulfonic
acids which are useful as detergents and dispersants in lubricants.
The book entitled "Lubricant Additives", C. V. Smallheer and R. K.
Smith, published by the Lezius-Hiles Co. of Cleveland, Ohio (1967),
similarly discloses a number of overbased sulfonates that are
useful as dispersants/detergents.
[0067] 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.
[0068] 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 a hydrogen atom or an alkyl group having 1 to 30 carbon
atoms, n is an integer from 1 to 4, and M is an alkaline earth
metal. Preferred R groups are alkyl chains of at least C.sub.11,
preferably C.sub.13 or greater. R may be optionally substituted
with substituents that do not interfere with the detergent's
function. M is preferably, calcium, magnesium, or barium. More
preferably, M is calcium.
[0069] 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.
[0070] Alkaline earth metal phosphates are also used as
detergents.
[0071] 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 for example.
[0072] Preferred detergents include calcium phenates, calcium
sulfonates, calcium salicylates, magnesium phenates, magnesium
sulfonates, magnesium salicylates and other related components
(including borated detergents). Typically, the total detergent
concentration is 0.01 to 6.0 wt %, preferably, 0.1 to 3.5 wt %.
[0073] 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.
[0074] Useful antioxidants include hindered phenols. These phenolic
anti-oxidants 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).
[0075] 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.
[0076] 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.
[0077] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0078] 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 wt %, preferably 0.01 to 1.5 wt %, more
preferably zero to less than 1.5 wt %, most preferably zero.
[0079] 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
poly-mrethacrylates, 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 wt %, preferably 0.01 to 1.5 wt
%.
[0080] 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 wt %, preferably 0.01 to 2 wt %.
[0081] 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 percent and
often less than 0.1 percent.
[0082] 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 metal-ligand
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. No.
5,824,627; U.S. Pat. No. 6,232,276; U.S. Pat. No. 6,153,564; U.S.
Pat. No. 6,143,701; U.S. Pat. No. 6,110,878; U.S. Pat. No.
5,837,657; U.S. Pat. No. 6,010,987; U.S. Pat. No. 5,906,968; U.S.
Pat. No. 6,734,150; U.S. Pat. No. 6,730,638; U.S. Pat. No.
6,689,725; U.S. Pat. No. 6,569,820; WO 99/66013; WO 99/47629; WO
98/26030.
[0083] Ashless friction modifiers may have 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.
[0084] Useful concentrations of friction modifiers may range from
0.01 wt % to 10-15 wt % or more, often with a preferred range of
0.1 wt % to 5 wt %. 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.
[0085] 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.
[0086] Note that many of the additives are shipped from the
manufacturer and used with a certain amount of base oil diluent in
the formulation. 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 wt % indicated below
are based on the total weight of the lubricating oil
composition.
TABLE-US-00002 TABLE 1 Typical Amounts of Various Lubricant Oil
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Detergent 0.01-6 0.01-4 Dispersant 0.1-20 0.1-8
Friction Modifier 0.01-5 0.01-1.5 Viscosity Index Improver 0.0-4
0.01-4, more preferably (solid polymer basis) 0.01-1, most
preferably Antioxidant 0.1-5 0.1-1.5 Anti-wear Additive 0.01-6
0.01-4 Pour Point Depressant 0.0-5 0.01-1.5 (PPD) Anti-foam Agent
0.001-3 0.001-0.3 Base stock or base oil Balance Balance
[0087] 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.
[0088] As will be seen from the Examples herein, the compositions
of the disclosure are sufficiently shear stable to provide
stay-in-grade performance. Additionally, the compositions
demonstrate surprising fuel economy performance in both diesel and
gasoline engines. Thus, the compositions described herein are
useful for lubricating diesel-powered and gasoline-powered,
internal combustion engines such as those used for example in
passenger vehicles, and in other classes of small engines such as
used in lawn mowers and chain saws. They are also useful for
lubricating diesel-powered engines such as those used in trucks,
construction machinery and marine diesel engines.
[0089] Accordingly, an improved method for lubricating internal
combustion engines is provided which comprises supplying to the
engine, when operated, a lubricating composition of the present
disclosure.
[0090] It should be understood that viscosities of the lubricant
compositions, lubricating components, and basestocks are measured
according to accepted procedures. Kinematic viscosity (KY) is
measured using ASTM D445, D7279, and comparable methods. High
temperature high shear viscosity (1HTHS) is measured using ASTM
D4683, CEC L-36, and comparable methods. Viscosity of such
materials may also be usefully characterized as a function of
temperature and shear rate, for example in the temperature range of
60.degree. C. to 160.degree. C., and shear rate range of 10.sup.3
sec.sup.-1 to 10.sup.8 sec.sup.-1.
EXAMPLES
[0091] The following examples further illustrate the present
disclosure. These examples are presented by way of illustration and
are not intended to limit the scope of the disclosure.
Example 1
[0092] A series of SAE 0W-30 diesel-type engine oils was formulated
to substantially the same low HTHS viscosity, i.e. 3 to 3.1 mPa-s,
and to substantially the same high HTHS viscosity, i.e. 3.4 to 3.6
mPa-s. The VM weight ratios ranged from 0.1 to 0.5. A major base
oil in each instance is a Group III base oil, and each lubricant
composition also contains Group IV and Group V base oils, and the
same additives combination in substantially the same amounts. The
example compositions along with a reference composition are shown
in Table A.
TABLE-US-00003 TABLE A Diesel Engine Oils, SAE 0W-30 -
Compositions, Properties Lubricant Composition* Active VM Wt Base
Base HTHS Ratio Active Stocks; Stocks; 10.sup.6 sec.sup.-1, VM
Types High-SSI/Low- VMs Grp III Grp IV 150.degree. C. KV100 Example
(nominal SSI) SSI (Wt %) (Wt %) (Wt %) (mPa-s) mm.sup.2/s A1
Paratone 8941 0.15 1.1 75 6 3.56 12.2 (50) SV200 (4) A2 Paratone
8941 0.24 1.1 75 5 3.50 12.1 (50) SV200 (4) A3 Paratone 8941 0.40
1.0 75 4 3.47 12.0 (50) SV200 (4) B1 Paratone 8941 0.15 0.8 74 4
3.11 10.0 (50) SV200 (4) B2 Paratone 8941 0.24 0.8 74 4 3.05 10.0
(50) SV200 (4) B3 Paratone 8941 0.41 0.7 74 3 3.13 10.1 (50) SV200
(4) Ref. 1 SV200 (4) 0.00 1.2 80 7 3.50 12.0 *Balance of lubricant
compositions include additives, Grp V base stock.
Example 2
[0093] A series of SAE 0W-30 gasoline-type engine oils was
formulated to the same low HTHS viscosity, i.e., 3 to 3.1 mPa-s,
and to substantially the same high HTHS viscosity, i.e., 3.4 to 3.6
mPa-s. The VM weight ratios ranged from 0.1 to 0.5. The base oil in
each instance is primarily a Group III base oil or a blend of Group
III and Group IV base oils. Each lubricant composition also
contains Group V base oil (alkyl aromatic and/or ester), and
substantially the same additives combinations in substantially the
same amounts. The example compositions along with reference
compositions are shown in Table B.
TABLE-US-00004 TABLE B Gasoline Engine Oils, SAE 0W-30 -
Compositions, Properties Lubricant Composition* Active VM Base Base
HTHS Wt Ratio Active Stocks; Stocks; 10.sup.6 sec.sup.-1, VM Types
High- VMs Grp III Grp IV 150.degree. C. KV100 Example (nominal SSI)
SSI/Low-SSI (Wt %) (Wt %) (Wt %) (mPa-s) mm.sup.2/s C1 Paratone
8941 0.14 1.2 74 6 3.53 12.2 (50) SV200 (4) C2 Paratone 8941 0.24
1.1 74 5 3.56 12.3 (50) SV200 (4) C3 Paratone 8941 0.40 1.0 74 4
3.57 12.1 (50) SV200 (4) D1 SV300 (59) 0.27 1.2 59 20 3.48 12.3
SV200 (5) E1 SV140 (58) 0.31 1.3 58 21 3.52 12.4 SV200 (4) F1
Paratone 8941 0.15 0.8 77 4 3.12 10.1 (50) SV200 (4) F2 Paratone
8941 0.24 0.8 76 4 3.14 10.1 (50) SV200 (4) F3 Paratone 8941 0.41
0.7 76 3 3.10 10.2 (50) SV200 (4) G1 SV261 (20) 0.62 1.0 49 32 3.46
12.2 SV200 (4) G2 SV151 (9) 0.36 1.1 48 33 3.46 12.2 SV200 (4) Ref.
2 SV200 (4) 0.00 1.2 80 7 3.50 12.0 Ref. 5 SV200 (4) 0.00 1.1 46 28
3.49 12.0 *Balance of lubricant compositions include additives, Grp
V base stock.
Example 3
[0094] In this example, oil compositions A1, A2, A3 and B1 of
Example 1 were tested in a passenger diesel vehicle with a
start-of-test (SOT) temperature of 22.degree. C., using the
European NEDC fuel economy test protocol. The fuel economy
improvement percent, % FEI, results are shown in Table C.
TABLE-US-00005 TABLE C Diesel Vehicle Fuel Economy Improvement, %
FEI (Mercedes Benz C250 CDI; NEDC Procedure; SOT Temp = 22.degree.
C.) Active VM Wt Ratio HTHS, 10.sup.6 sec.sup.-1 , Example
High-SSI/Low-SSI 150.degree. C. (mPa-s) % FEI Al 0.15 3.56 0.59 A2
0.24 3.50 1.02 A3 0.40 3.47 1.33 B1 0.15 3.11 1.59 Reference 1 0
3.5 .ltoreq.0.2 (Extrapolated from A1, A2, A3) Reference 3 0 3.5 0
(Zero Reference MB 225.11)
[0095] As can be seen from oils A1 to A3, the % FEI increases with
increasing VM wt ratios of high-SSI/low-SSI. In Reference 1, the VM
wt ratio=0, since only SV200 was used in that composition. Thus,
oils A1 to A3, which each contain an effective amount of high-SSI
VM, achieve significantly higher fuel efficiency, % FEI, than that
of Reference 1 which contains zero high-SSI VM.
[0096] A comparison of oil B1 (HTHS viscosity of 3.11 mPa-s) with
oil A1 (HTHS viscosity of 3.56 mPa-s) demonstrates that the same
combination of high-SSI VM and low-SSI VM will provide positive %
FEI for oils having different HTHS viscosities, both low and high
viscosities, respectively.
Example 4
[0097] Gasoline-type engine oil compositions C1, C3, D1 and E1 of
Example 2 were tested in a passenger gasoline vehicle with a
start-of-test (SOT) temperature of 22.degree. C., using the
European NEDC fuel economy test protocol. The fuel economy
improvement percent, % FEI, results are shown in Table D.
TABLE-US-00006 TABLE D Gasoline Vehicle Fuel Economy Improvement, %
FEI (Mercedes Benz C200; NEDC Procedure; SOT Temp = 22.degree. C.)
Active VM Wt Ratio HTHS, 10.sup.6 sec.sup.-1, Example
High-SSI/Low-SSI 150.degree. C. (mPa-s) % FEI Cl 0.14 3.53 0.76 C3
0.40 3.57 1.36 D1 0.27 3.48 2.12 E1 0.31 3.52 1.00 Reference 2 0
3.5 .ltoreq.0.4 (Extrapolated from C.sub.1, C.sub.3) Reference 4 0
3.5 0 (Zero Reference MB 225.10)
[0098] The results for oils C1 and C3 demonstrate that % FEI
increases with increasing VM wt ratio of high-SSI/low-SSI. The
results for oils D1 and E1 demonstrate that different VM materials
also can be used to achieve a positive % FEI result. The lubricant
compositions of this Example, which each contain an effective
amount of high-SSI VM, achieve significantly higher fuel
efficiency, % FEI, than that of Reference 2 which contains zero
high-SSI VM.
Example 5
[0099] Gasoline-type engine oil compositions G1 and G2 of Example 2
were tested in a Volkswagen gasoline engine with a start-of-test
(SOT) temperature of -7.degree. C., using the fuel economy test VW
PV 1451. The fuel economy improvement percent, % FEI, results are
shown in Table E.
TABLE-US-00007 TABLE E Gasoline Vehicle Fuel Economy Improvement, %
FEI (VW PV 1451) Active VM Wt Ratio HTHS, 10.sup.6 sec.sup.-1,
Example High-SSI/Low-SSI 150.degree. C. (mPa-s) % FEI G1 0.62 3.46
2.6 G2 0.36 3.46 2.6 Reference 5 0 3.49 2.2 Reference 6 0 3.5 0
(Zero Reference VW)
[0100] The results for oils G1 and G2 demonstrate that % FEI
increases with increasing VM wt ratio of high-SSI/low-SSI. The
lubricant compositions of this Example, which each contain an
effective amount of high-SSI VM, achieve significantly higher fuel
efficiency, % FEI, than that of Reference 5, which contains zero
high-SSI VM, but which is otherwise essentially identical in
composition.
Example 6
[0101] The diesel-type oil compositions A1 to A3 and B1 to B3 of
Example 1 were tested for shear stability using test method ASTM
D7109. The KV at 100.degree. C. after 90 cycles is shown in Table
F.
TABLE-US-00008 TABLE F Diesel Engine Oils, SAE 0W-30 - Shear
Stability Active VM Wt HTHS Diesel Injector Shear Stability-D7109
Ratio 10.sup.6 sec.sup.-1, KV100 KV100 % Loss Stay-in-Grade
High-SSI/Low- 150.degree. C. (fresh oil) (90 cycles) KV100 (90 (for
SAE 0W-30, Example SSI (mPa-s) mm.sup.2/s mm.sup.2/s cycles) KV100
.gtoreq.9.3 mm.sup.2/s A1 0.15 3.56 12.15 11.31 6.9 Yes A2 0.24
3.50 12.10 10.96 9.4 Yes A3 0.40 3.47 11.97 10.52 12.1 Yes B1 0.15
3.11 9.96 9.52 4.4 Yes B2 0.24 3.05 10.01 9.31 7.0 Yes B3 0.41 3.13
10.05 9.13 9.2 No
[0102] Even though Example B3 contains a mixed high-SSI VM and
low-SSI VM in the inventive range of VM weight ratio, it fails to
meet the stay-in-grade shear stability requirement. This clearly
demonstrates that viscosity retention and stay-in-grade shear
stability represent a significant limitation to the use of mixed VM
polymers in the instant disclosure. So stay-in-grade shear
stability controls and limits the selection of VM weight ratio and
VM concentrations to those compositions that are effective in
providing improved fuel economy performance.
Example 7
[0103] Gasoline-type oil compositions C1 to C3, D1, E1 and F1 to F3
of Example 2 were tested for shear stability using test method ASTM
D7109. The results are shown in Table G.
TABLE-US-00009 TABLE G Gasoline Engine Oils, SAE 0W-30 - Shear
Stability Diesel Injector Shear Stability- Active VM Wt HTHS D7109
Ratio 10.sup.6 sec.sup.-1, KV100 KV100 % Loss Stay-in-Grade
High-SSI/Low- 150.degree. C. (fresh oil) (90 cycles) KV100 (for SAE
0W-30, Example SSI (mPa-s) mm.sup.2/s mm.sup.2/s (90 cycles) KV100
.gtoreq.9.3 mm.sup.2/s C1 0.14 3.53 12.20 11.37 6.8 Yes C2 0.24
3.56 12.27 11.14 9.2 Yes C3 0.40 3.57 12.10 10.61 12.3 Yes D1 0.27
3.48 12.27 10.2 <17 Yes E1 0.31 3.52 12.35 10.1 <18 Yes F1
0.15 3.12 10.11 9.59 5.1 Yes F2 0.24 3.14 10.13 9.47 6.5 Yes F3
0.41 3.10 10.19 9.26 9.1 No G1 0.62 3.46 12.2 11.9 2.6 Yes G2 0.36
3.46 12.2 12 2 Yes
[0104] Even though Example F3 contains a mixed high-SSI VM and
low-SSI VM in the inventive range of VM weight ratio, it fails to
meet the stay-in-grade shear stability requirement. This provides
another illustration that viscosity retention and stay-in-grade
shear stability represent a significant limitation to the use of
mixed VM polymers in the instant disclosure.
[0105] 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.
[0106] 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.
[0107] 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