Note: Descriptions are shown in the official language in which they were submitted.
CA 02248368 2004-O1-12
SUBSTANTI ALLY LINEAR ETHYLENE/ALPHA-OLEFIN
POLYMERS AS VISCOSITY INDEX IMPROVERS OR GELLING
AGENTS
This invention relates generally to oleaginous
compositions that contain at least one ethylene/alpha-olefin
(a-olefin) interpolvmer as a viscosity index (VI) improver or as a
gelling agent. This invention relates more particularly to such
compositions wherein the interpolymer is substantially linear.
especially with a homogeneous branching distribution and a
narrow molecular weight distribution (MWD). The interpolymer
may be modified by one or more further reactions to provide
additional functionality. One such reaction of particular interest
involves grafting an olefinically unsaturated organic compound,
such as malefic anhydride, onto the interpolymer. The resulting
grafted polymer may then be further reacted with one or more
additional compounds such as an amine.
A VI improver, when incorporated into an oleaginous
composition, provides the composition with a desirable or improved
viscosity at elevated temperatures. An improvement or increase in
elevated temperature viscosity, without other changes. translates
to a VI improvement.
A VI is an empirical number used as a measure of
lubricant viscosity and temperature stability. A high VI indicates
resistance to thinning at elevated or high temperatures. A low VI
indicates a tendency toward thinning at those temperatures.
VI improver performance indicators include
thickening power, shear stability, and chemical and thermal
oxidative stability, all of which are related to
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polymer structure. The ability of a given VI improver to provide
desirable high temperature viscometric behavior depends upon
factors such as polymer molecular weight, concentration and
chemical structure relative to chemical structure of the oleaginous
composition. Shear stability depends largely upon polymer
molecular weight and MWD.
A variety of oil soluble polymers have been used as VI
improvers for lubricating oils. Illustrative polymers include
hydrogenated styrene/diene polymers, hydrogenated
polyisoprenes, polyalkylmethacrylates, and ethylene/a-olefin
copolymers such as ethylene/propylene copolymers and ethylene/-
propylene/diene terpolymers as well as various derivatives of these
copolymers and terpolymers. These polymers allow preparation of
multigrade oils (e.g. lOW-30), those that meet both high and Iow
temperature SAE (Society of Automotive Engineers) viscometric
requirements.
At least some of the oil soluble polymers are also
useful as thickeners or gelling agents for other oleaginous
materials such as mineral oils, paraffinic oils and naphthenic oils
to prepare compositions suitable for use as greases or cosmetic
materials.
VI improvers based on ethylene olefin copolymers
prepared in the presence of metallocene catalysts have also been
disclosed, for example in USP 5,151,204 and USP 5,446,221.
Summary of the Invention
An aspect of the invention is an oleaginous
composition comprising an oleaginous material and a viscosity
modifying effective amount of a substantially linear ethylene
polymer (SLEP), the SLEP being characterized as having: (i) a melt
flow ratio, Ilo/Iz, >_ 5.63; (ii) a MW~D, Mw/Mn, defined by an
equation wherein MW/Mt, <_ (Ilo/Iz) - 4.63; and (iii) a critical shear
rate at onset of surface melt fracture (OSMF) of at least 50 percent
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(%) greater than the critical shear rate at OSMF of a linear olefin
polymer having a similar Iz and MW/Mn.
In a first related aspect, the amount of polymer is a
thickening or gelling effective amount whereby the composition is
rendered suitable for use in preparing greases or cosmetic
materials.
In a second related aspect, the oleaginous composition
further comprises an amount of a pour point depressant (PPD)
sufficient to improve low temperature properties of the composition
relative to a like composition that lacks the PPD.
In a third related aspect, at least a portion of the
SLEP is replaced with a shear-modified SLEP, whereby shear
stability of the oleaginous composition is increased. The shear-
modified polymer is suitably prepared by subjecting a SLEP to a
shearing action sufficient to increase its melt index (IZ).
In a fourth related aspect, the oleaginous composition
further comprises, in addition to the SLEP(s}, at least one polymer
selected from hydrogenated polyisoprenes, styrene/butadiene
block polymers, styrene/isoprene block polymers, hydrogenated
styrene/butadiene block polymers, hydrogenated styrene/isoprene
block polymers, grafted styrene/butadiene block polymers, grafted
styrene/isoprene block polymers, polyalkylmethacrylates,
polyalkylacrylates, ethylene polymers, and acrylate/methacrylate
copolymers.
Each of the aspect and the related aspects has three
further related aspects (a) through (c). In aspect (a}, the SLEP has
an ethylene content within a range of from 20 to 80 weight percent
(wt%), based upon polymer weight. In aspect (b), the SLEP is
grafted with at least 0.01 wt %, based on weight of grafted SLEP, of
an unsaturated organic compound that contains a graftable
moiety. In aspect (c), the grafted SLEP, that contains a reactive
moiety, is further reacted with a compound having a hydroxyl or
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an amine functionality. Illustrative compounds include alcohols,
especially aliphatic saturated mono alcohols, acids and amines,
especially primary amines.
"Block polymer" includes diblock polymers. triblock
polymers, radial block or star block polymers and tapered
interpolymers.
"Ethylene polymers" means an ethylene/a-olefin
copolymer or dime modified ethylene/a-olefin copolymer.
Illustrative polymers include ethylene/propylene (EP) copolymers,
ethylene/octene (EO) copolymers and ethylene/propylene/diene
modified (EPDM) interpolymers.
"Substantially linear" means that a polymer has a
backbone substituted with from 0.01 to 3 long-chain branches per
1000 carbons in the backbone.
"Long-chain branching" or "LCB " means a chain
length of at least 6 carbon atoms. Above this length, carbon-13
nuclear magnetic resonance (C-13 NMR) spectroscopy cannot
distinguish or determine an actual number of carbon atoms in the
chain. In some instances, a chain length can be as long as the
polymer backbone to which it is attached.
"Interpolymer" refers to a polymer having polymerized
therein at least two monomers. It includes, for example, copolymers,
terpolymers and tetrapolymers. It particularly includes a polymer
prepared by polymerizing ethylene with at least one comonomer,
typically an a-olefin of 3 to 20 carbon atoms (C3-Caol. Illustrative a-
olefins include propylene, 1-butene. 1-hexene, 4-methyl-1-pentene,
1-heptene, 1-octene and styrene. The a-olefin is desirably has a C3-Coo
a-olefin. Preferred copolymers include EP and ethylene-octene.
Illustrative terpolymers include an ethylene/propylene/octene
terpolymer as well as terpolymers of ethylene, a Cs-Czo a-olefin and a
dime such as dicyclopentadiene. 1,4-hexadiene, piperylene,
5-ethylidene-2-norbornene, 1,7-octadiene and vinyl norbornene.
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The substantially linear ethylene a-olefin
interpolymers ("SLEPs " or "substantially linear ethylene polymers")
may be prepared as described in United States Patent (USP)
5,272,236 and 5,278,272,
USP 5,2?2,236 (column 5, Line
fi7 through column 6, line 28) describes SLEP production via a
continuous controlled polymerization process using at least one
reactor, but allows for multiple reactors, at a polymerization
temperature and pressure sufficient to produce a SLEP having
desired properties. Polymerization preferably occurs via a solution
polymerization process at a temperature of from 20°C to 250°C,
using constrained geometry catalyst technology.
Suitable constrained geometry catalysts,are
disclosed at column 6, line 29 through column 13, line 50 of USP
5,272,236. These catalysts may be described as comprising a
metal coordination complex that comprises a metal of groups 3-10
or the Lanthanide series of the Periodic Table of the Elements and
a delocalized pi-bonded moiety substituted with a constrain-
inducing moiety. The complex has a constrained geometry about
the metal atom such that the angle at the metal between the
centroid of the delocalized, substituted pi-bonded moiety and the
center of at least one remaining substituent is less than such angle
in a similar complex containing a similar pi-bonded moiety lacking
in such constrain-inducing substituent. If such complexes
comprise more than one delocalized, substituted pi-bonded moiety,
only one such moiety for each metal atom of the complex is a
cyclic, delocalized, substituted pi-bonded moiety. The catalyst
further comprises an activating cocatalyst such as tris(pentafluoro-
phenyl)borane. Specific catalyst complexes are discussed in USP
5,272,236 at column 6, line 57 through column 8, line 58 and in
USP 5,2?8.272 at column 7, line 48 through column 9, line 37.
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A SLEP is characterized by a narrow MWD and, if
an interpolymer, by a narrow comonomer distribution. A SLEP is
also characterized by a low residuals content, specifically in terms
of catalyst residue, unreacted comonomers and low molecular
weight oligomers generated during polymerization. A SLEP is
further characterized by a controlled molecular architecture that
provides good processability even though the MWD is narrow
relative to conventional olefin polymers.
A preferred SLEP has a number of distinct
characteristics, one of which is a comonomer content that is
between 20 and 80 wt%, more preferably between 30 and 70 wt%,
ethylene, with the balance comprising one or more comonomers.
SLEP comonomer content can be measured using infrared (IR)
spectroscopy according to ASTM D-2238 Method B or ASTM D-
3900. Comonomer content can also be determined by C-13 NMR
Spectroscopy.
Additional distinct SLEP characteristics include Ia
and melt flow ratio (MFR or Iio/Iz). The interpolymers desirably
have an IZ (ASTM D-1238, condition 190°C/2.16 kilograms (kg)
(formerly condition E), of 0.01-500 grams/ 10 minutes (g/ 10 min),
more preferably from 0.05-50 g/ 10 min. The SLEP also has a MFR
(ASTM D-1238) >_ 5.63, preferably from 6.5-15, more preferably
from 7 to 10. For a SLEP, the Ilo/Iz ratio serves as an indication of
the degree of LCB such that a larger Iio/Iz ratio equates to a higher
degree of LCB in the polymer.
A further distinct characteristic of a SLEP is MWD
(MW/Mn or "polydispersity index "), as measured by gel permeation
chromatography (GPC). MW/Mn is defined by the equation:
Mw/Mn ~ (llo/I2) - 4.63
The MWD is desirably > 0 and < 5, especially from 1.5 to 3.5, and
preferably from 1.7 to 3.
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A homogeneously branched SLED 5urpriWngl,r has a
MFR that is essentially independent of its ~IWD. This contrasts
markedly with conventional linear homogeneously branched and
linear heterogeneously branched ethylene copolymers where the
MWD must be increased to increase the MFR.
A SLEP may be still further characterized as haW ng a
critical shear rate at OSMF of at least 50 °o greater than the critical
shear rate at the OSMF of a linear olefin polymer that has a like I2
and Mw~IVIn.
SLEPs that meet the aforementioned criteria include,
for example, ENGAGET~I polyolefin elastomers and other polymers
produced via constrained geometry catalysis by DuPont Dow
Elastomers L.L.C.
A SLEP may be added to oleaginous compositions with
or without modification such as grafting. If modified by grafting, a
resulting grafted SLEP may also be added to oleaginous
compositions with or without one or more further reactions prior to
addition. Grafting may also be done after a SLEP is added to an
oleaginous composition.
:any unsaturated organic compound that contains at least one
ethylenic unsaturation (at least one double bond), and will graft to a
SLEP can be used to modify a SLEP. Illustrative unsaturated compounds
include vinyl ethers, vinyl-substituted heterocyclic compounds, vinyl
oxazolines. vinyl amines, vinyl epoxies, unsaturated epoxy compounds,
unsaturated carboxylic acids, and anhydrides, ethers, amines, amides,
succinimides or esters of such acids. Representative compounds include
malefic, fumaric, acrylic, methacrylic, itaconic, crotonic, a-methyl
crotonic. and cinnamic acid and their anhydride, ester or ether
derivatives, vinyl-substituted alkylphenols and glycidyl methacrylates.
Suitable unsaturated amines include those of aliphatic and heterocyclic
organic nitrogen compounds that contain at least one double bond and
at least one amine group (at least one primary, secondary or
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tertiary amine). Representative examples include vinyl pyridine
and vinyl pyrrolidone. Malefic anhydride is the preferred
unsaturated organic compound.
The unsaturated organic compound content of a
grafted SLEP is z 0.01 wt9io, and preferably 2 0.05 wt%, based on
the combined weight of the polymer and the organic compound.
The maximum unsaturated organic compound content can vary,
but is typically S 10 wt %, preferably <_ 5 wt%, more preferably <_ 2
wt~b.
A unsaturated organic compound can be grafted to
a SLEP by any known technique, such as those taught in USP
3,236,917 and USP 5,194,509.
In USP 3,236,917, a polymer, such as an EP copolymer, is
introduced into a two-roll mixer and mixed at a temperature of 60°
Centigrade (°C}. The unsaturated organic compound, such as
malefic anhydride, is then added along with a free radical initiator,
such as benzoyl peroxide, and the components are mixed at 30°C
until graftfng is complete.
USP 5,194,509 discloses a procedure like that of
USP 3,236.917, but with a higher reaction temperature (210°C to
300°C, preferably 210°C to 280°C) and either omitting or
limiting
free radical initiator usage. USP 5,194,509 specifically teaches that
peroxide-free grafting of unsaturated carboxylic acids, anhydrides
and their derivatives can be carried out in a conventional twin-
screw extruder, like a ZDSK 53 from Werner & Pfleiderer, or some
other conventional apparatus such as a Brabender reactor. The
ethylene polymer and, if required, the monomer to be grafted are
melted at 140°C or higher, mixed thoroughly and then reacted at
elevated temperatures (from 210°C to 300°C, preferably from
210°C to 280°C, more preferably from 210°C to
260°C). It is not
important whether the monomer to be grafted is introduced into
the reactor before or after the ethylene polymer is melted. The
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CA 02248368 2004-O1-12
monomers to be grafted are used in a concentration of 0.01-0.5.
preferably from 0.05-0.25, wt9~o, based on ethylene polymer weight
An alternative and preferred method of grafting is
taught in USP 4,950,541,
The alternative method employs
a twin-screw devolatilizing extruder as a mixing apparatus. The
SLEP and unsaturated organic compound are mixed and reacted
within the extruder at temperatures at which the reactants are
IO molten and in the presence of a free radical initiator. The
unsaturated organic compound is preferably injected into a zone
that is maintained under pressure within the extruder.
A second, alternative and preferred method of
grafting is solution grafting as taught in USP 4,810,754,
The method involves mixing an initiator, a monomer to be grafted
and a polymer, such as an EP polymer, in a solvent, such as
mineral oil, and then reacting at a temperature sufficient to initiate
the grafting reaction. One such temperature is 190°C.
A graft-modified SLEP may be subjected to a
further reaction with a modifying material to introduce one or more
additional functionalities that lead(s), in turn, to improved
25 properties, such as improved dispersability of oxidative or
combustion byproducts, improved low temperature viscosity and
improved oxidative/thermal stability, in an oleaginous composition
that contains a grafted and further reacted SLEP. Illustrative
modifying materials include alcohols, long chain (typically up to 36
carbon atoms) fatty acids, and amines. Examples of alcohols
include aliphatic and aromatic alcohols having 2 two carbon
atoms, preferably > 12, more preferably < 36 carbon atoms.
Representative alcohols and long chain fatty acids include decyl,
lauryl and stearyl alcohols and acids. Examples of amines include
35 those of aliphatic and heterocyclic nitrogen compounds containing
>_ one primary and/or >_ one secondary, and optionally, >_ one
tertiary amine. Certain amines, such as triethylene tetramine,
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tetraethylene pentamine, and polyethylene polyamines (such as
Ethyleneamine E-100, commercially available from The Dow
Chemical Company) have both aliphatic and heterocyclic moieties.
Commercial polyethylene polyamines are typically blends or
mixtures of linear, branched and heterocyclic amines.
Representative examples include polyethylene amines (such as
diethylene triamine), I-(3-aminoethyl imidazole), aminoethyl
piperazines, 4-(3-aminopropyl} morpholine and polyoxyalkylene
polyamines (such as Jeffamines'~' produced by Huntsman
Chemical). Additional alcohols and amines are disclosed in USP
5,401,427, particularly at column 45, line 40, through column 49,
line 29,
USP 5,401,42? teaches that other suitable alkylene
polyamines include methylene amines, ethylene amines, butylene
amines, propylene amines, pentylene amines, hexylene amines,
heptylene amines, octylene amines, other polymethylene amines,
the cyclic and higher homologs of these amines such as the
piperazines, the amino-alkyl-substituted piperazines, etc. These
amines include, for example, ethylene diamine, diethylene
triamine, triethylene tetramine, propylene diamine, di(-
heptamethylene)triamine, tripropylene tetramine, tetraethylene
pentamine, trimethylene diamine, pentaethylene hexamine,
di(trimethylene)triamine, 2-heptyl-3-(2-aminopropyl)imidazoline, 4-
methyIimidazoline, 1,3-bis-(2-aminopropyl)imidazoline, pyrimidine,
I-(2-aminopropyl)piperazine, 1,4-bis(2-aminoethyl)piperazine, N,N'-
dimethyaminopropyl amine, N.N'-dioctylethyl amine, N-octyl-N'-
methylethylene diamine, and 2-methyl-1-(2-aminobutyl)pfperazine.
Included within the scope of the term polyamines are the
hydroxyalkyl polyamines, particularly the hydroxyalkyl alkylene
polyamines, having one or more hydroxyalkyl substituents on the
nitrogen atoms. Examples of such hydroxyalkyl-substituted
polyamines include N-(2-hydroxyethyl)ethylene diamine, N,N-bis(2-
hydroxyethyl)ethylene diamine, 1-(2- hydroxyethyl)-piperazine,
monohydroxy-propyl-substituted diethylene triamine,
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dihydroxypropyl-substituted tetraethylene pentamine, and N-(3-
hydroxybutyl)tetramethylene diamine.
Alcohols or polyols disclosed in USP 5,401,427
include aliphatic polyhydric alcohols containing <_ 100 carbon
atoms and 2 to 10 hydroxyl groups. These alcohols can be
substituted or unsubstituted, hindered or unhindered, or
branched chain or straight chain, as desired. Typical alcohols are
alkylene glycols such as ethylene glycol, propylene glycol,
trimethylene glycol, butylene glycol, and polyglycols such as
diethylene glycol, triethylene glycol, tetraethylene glycol,
dipropylene glycol, tripropylene glycol, dibutylene glycol,
tributylene glycol, and other alkylene glycols and polyalkylene
glycols in which the alkylene radical contains from 2 to 8 carbon
atoms. A preferred class of aliphatic alcohols containing <_ 20
carbon atoms includes glycerol, erythritol, pentaerythritol,
dipentaerythritol, tripentaerythritol, gluconic acid,glyceraldehyde,
glucose, arabinose, 1,7-heptanediol, 2,4-heptanediol, 1,2,3-
hexanetriol, 1,2,4-hexanetriol, 1,2,5-hexanetriol, 2,3,4-hexanetriol,
1,2,3-butanetriol, 1,2,4-butanetriol, 2,2,6,6,-
tetrakis(hydroxymethyl)-cyclohexanol, and 1,10-decanediol.
A SLEP, graft-modified SLEP and/or further
reacted, graft modified SLEP, when added to a variety of base oils
or oleaginous materials, improves) at least one of VI
measurements, dispersancy measurements, stability
measurements and gelling or thickening measurements of such
oleaginous materials relative to the oleaginous materials lacking
such a SLEP or such a graft-modified SLEP or such a further
reacted, graft-modified, SLEP.
Oleaginous materials or base oils suitable for use in
lubricating oil formulations can comprise unrefined, refined and
redefined (reclaimed) oils utilizing both natural and synthetic
sources. Illustrative oleaginous materials include any of a variety
of hydrocarbon oils, lubricating oils based on alkylene oxide
polymers and their derivatives, oils which are esters of dicarboxylic
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acids, or silicon-based oils, to form the compositions of the present
invention. Such oils may be natural or synthetic and include
lubricating oil and fuel oils. Examples of suitable oils include
liquid petroleum oils, lubricating oils of the paraffinic, naphthenic
5 and mixed paraffinic-naphthenic types, oils derived from coal or
shale, poly(a-olefin) oils, vegetable oils, animal oils,
polyoxyalkylene polymers or copolymers prepared from one or
more of ethylene oxide, propylene oxide or butylene oxide,
tetrahydrofuran, polyalkyl-, polyaryl-, polyalkoxy-, or
10 polyaryloxysiloxane oils, and silicate oils. Blends of such oils may
also be used. USP 5.446,221 discloses, at column 8, line 47
through column 10, line 34, additional information about various
oleaginous materials,
15 When a SLEP, whether ungrafted, grafted or grafted and
further reacted, is used as a VI modifier in an oleaginous
composition, the composition may also contain several different
types of additives that augment characteristics required in a
formulation that contains such compositions. These additives,
20 which may include a conventional VI improver, generally include
dispersants, detergents, antioxidants, anti-wear and pressure
agents, friction modifiers, PPDs, corrosion inhibitors, ashless
dispersants (such as polyisobutenyl succinimides and their
borated derivatives) and antifoamants. These additives are
25 generally present in amounts of 0.001 - 20 wt%, based on the
weight of the oil. Conventional VI improvers include high molecular
weight hydrocarbon polymers, polyalkylmethacrylates, and
polyesters containing copolymerized units of unsaturated C3 to Cg
mono and dicarboxylic acids. The additives may be introduced as
30 concentrated solutions or dispersions in oil or without dilution.
In preparing lubricating oil formulations, additives
are commonly introduced as 5 to 80 wt°rb active ingredient
concentrates in oil. The use of concentrates makes handling of the
35 various materials less difficult and facilitates solution or dispersion
of the additives in the formulation.
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PPDs lower the temperature at which the
lubricating oil will flow or can be poured. Such PPDs are well
known. Typical of those additives which can be used for low
temperature fluidity of lubricating oil are dialkylfumarate vinyl
acetate copolymers, polymethacrylates (USP 2,091,627 and
2,100,993)and wax naphthalene (USP 2,174,246).
When a SLEP, whether ungrafted, grafted or grafted and
further reacted, is added to an oleaginous composition as a thickener or
gelling agent in the preparation of greases, materials for wire and
cable end use applications or thixotropic gelling agents, it may be
combined with arty or ail of the additives specified as useful for
oleaginous compositions used as lubricating oils. Illustrative wire
and cable end use applications include conventional uses such as
potting compounds, water barriers and insulation materials.
These applications are particularly important for optical fiber
cables.
When such polymers are added to oleaginous
compositions as thickeners or gelling agents for cosmetic
applications, salves or external medicinal applications, they may
be combined with other additives such as fragrances, colorants,
dyes, stabilizers, surfactants, emollients, and oils (such as coconut
oil).
Oleaginous compositions that exhibit improved low
temperature properties comprise an oleaginous material, a PPD
and a viscosity modifying effective amount of a SLEP. When the
SLEP is essentially amorphous (it may contain <_ 6 % crystallinity,
preferably <_ 3 and more preferably <_ 1, but >_ 0, % crystallinity),
any conventional PPD may be used provided the onset of
crystallization (T~) for waxes) contained in the oleaginous material
is not within a range for T~ of waxes contained in the SLEP. When
the SLEP is semi-crystalline (a crystallinity of 6 to 25 %, preferably
6 to 20 %, more preferably 6 to 16 %), satisfactory low temperature
properties are attained with certain preferred PPDs that are
copolymers of di-n-alkyl fumarates and vinyl acetate. The
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copolymers used as PPDs are suitably prepared as described in
USP 4,839,074,
USP 4,839,074 teaches, in part, that dicarboxylic
acids, such as fumaric acid, are first esterified and then reacted or
copolymerized with a polymerizable monomeric compound, such as
a vinyl ester, using conventional free radical polymerization
techniques to yield random polymers. Polymerization suitably
occurs in an inert hydrocarbon solvent, such as hexane or
heptane, in an oxygen-free environment, such as a nitrogen
atmosphere, at temperatures of 65°C to 150°C. While complete
esterification of all of the carboxyl groups of the dicarboxylic
monomer is preferred, partial esterification, of z 70 mole °r6 of
I5 available esterifiable carboxyl groups, may be sufficient.
Esterification is typically conducted with mixtures of alcohols. The
alcohols may be slightly branched, but are preferably straight
chain C, to Czo aliphatic alcohols, more preferably Cs to Clo
aliphatic alcohols.
It is believed that a semicrystalline SLEP that works
well with a di-n-alkyl fumarate/vinyl acetate copolymer has a peak
crystallization temperature (as determined by differential scanning
calorimetry (DSC)) that differs from that of waxes) contained in the
oleaginous material such that the SLEP and waxes) contained in
the oleaginous material desirably do not co-crystallize. As peak
crystallization temperatures of oleaginous materials vary
considerably due to factors such as wax content, each combination
of oleaginous material, semicrystalline SLEP and di-n-alkyl
fumarate/vinyl acetate copolymer must be evaluated for low
temperature properties.
The compositions of the present invention are
formed by adding a SLEP, with or without modification such as by
grafting and, if grafted, with or without further reaction, to an oil
or oleaginous composition by conventional blending techniques.
The polymers may be added neat or as oil concentrates. Generally,
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the amount of polymer added will be in a range of from 0.1 to 20
wt% as dry polymer, based on weight of the oil to be modified,
preferably 0.2 to 5 wt% dry polymer for viscosity modification and
to 15 wt% dry polymer for thickening or gelling applications.
5
In preparing lubricating oil formulations, additives
are commonly introduced as active ingredient concentrates in a
hydrocarbon oil, such as a mineral lubricating oil, or some other
suitable solvent. The concentrates typically have an active
ingredient content of 5 to 80 wt%, based upon concentrate weight.
In forming finished lubricants, such as crankcase motor oils,
concentrates are usually diluted with 3 to 100, sometimes 5 to 40,
parts by weight (pbw) of lubricating oil per pbw of an additives
package. Concentrate use makes handling various additives less
difficult and awkward and may facilitate solution or dispersion of
additives in a finished lubricant. By way of example, a typical VI
improver would be employed as a of 5 to 20 wt% concentrate in a
lubricating oil fraction.
This invention relates in part to oleaginous or oil
compositions exhibiting improved VI, especially to oil compositions
comprising lubricating oil and, as a VI improver, a SLEP. Oil
compositions that contain such a VI improver exhibit improved
viscosity at elevated temperatures as compared to oil compositions
that do not contain such a VI improver. The VI improvers may also
be derivatized to impart other properties or functions, such as the
addition of dispersant properties to fuel and lubricating oil
compositions. The derivatized polymers include grafted SLEPs
such as a malefic anhydride grafted SLEP (prepared as described
above and in column 3, line 67 through column 4, line 24 of USP
5,346,9F3) which may be further reacted with an alcohol, or amine
such as shown in USP 3,702,300 (column 4, line 56 through
column 5, line 60, relating to esterification of a carboxy-containing
interpolymer, such as a malefic anhydride-containing interpolymer,
with mixed alcohols and then neutralizing remaining carboxy
radicals with a polyamine): USP 4,089,794 (column 3, line 37
through column 4, line 59, relating to solution grafting an
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ethylenically unsaturated carboxylic acid material, such as malefic
anhydride, onto an ethylene/a-olefin polymer, such as an EP
copolymer, and then reacting a polyamine with the grafted
polymer); USP 4,160,739 (column 6, lines 35-52, relating to post-
s reaction of carboxyl groups provided by malefic acid or anhydride
grafts with a non-polymerizable polyamine): or USP 4,137,185
(column 7, lines 4-17, relating to reacting, in solution, a grafted
carboxylic acid material, such as malefic anhydride grafted
ethylene/a-olefin polymer with a poly(primary amine)): or a SLEP
grafted with nitrogen compounds such as shown in USP 4,068,056
(column 4. line 47 through column 5, line 23, relating to reacting a
Ziegler-Natta catalyzed hydrocarbon polymer, in the presence of an
oxygen-containing gas, with an amine compound while mixing the
polymer and amine compound at 130°C to 300°C); USP 4,146.489
(column 2, Iine 49 through column 3, line 15, relating to free
radical graft polymerization of a C-vinylpyridine or N-vinyl
pyrrolidone onto an EP rubber or EPDM rubber); and USP
4,149,984 (column 4, Iines 3-20, relating to grafting a
polymerizable heterocyclic compound, such as vinyl pyridine or
vinyl pyrrolidone, onto a polymer formed by polymerizing a
methacrylic acid ester of a Cs-Cis alcohol in a solution of a
polyolefin polymer).
The following examples illustrate but do not,
either explicitly or by implication, limit the present invention.
Unless otherwise stated, all parts and percentages are by weight.
on a total weight basis.
Exam~lgs
Eleven primary polymers, eight representing the
present invention, were used in the examples. Polymers B, E and I
do not represent the invention. The polymers were:
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, An ethylene/octene copolymer (ethylene content of
61.7 wt%) commercially available from DuPont Dow Elastomers
L.L.C. as EG 8200.
B. An ethylene/butene copolymer commercially
available from Eon Chemical Company as EXACTTN' 4024.
C, An ethylene/octene copolymer (ethylene content
of 68.2 wt%) commercially available from DuPont Dow Elastomers
L.L.C. as EG 8100.
D, A developmental ethylene/propylene/ethylidene
norbornene terpolymer (ethylene content of 57 wt%) made by
DuPont Dow Elastomers L.L.C.
E, An EP copolymer commercially available from
Mitsui Petrochemical as TAFMERT"' P-0480.
F, An ethylene/octene copolymer (ethylene content
of 64.7 wt%) commercially available from DuPont Dow Elastomers
L.L.C. as EG 8150.
G, An ethylene/octene copolymer (ethylene content
of 61.0 wt%) commercially available from DuPont Dow Elastomers
L.L.C. as DEG 8180.
H, A developmental EP copolymer (ethylene content
of 53.1 wt%) made by DuPont Dow Elastomers L.L.C.
I. An EP copolymer commercially available from
Mitsui Petrochemical as TAFMERTM P-0480.
J, A developmental EP copolymer (ethylene content
of 34.7 wt%) made by DuPont Dow Elastomers L.L.C.
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K, A developmental ethylene/styrene copolymer
(ethylene content of 60 wt%) made by The Dow Chemical
Company.
Tables IA and IB contain physical propel-ty
information for primary polymers A-K.
T~hIP TA
Polymer/ A B C D E F
Property
I2 (g/10 5.0 3.3 1.0 1.72 1.1 0.50
min)
Density 0.8700.8780.8700.8600.8700.868
(glcm3)
I,o/IZ 7.38 5.8 7.99 8.13 6.06 7.37
Ratio
Mwnvi" 1.92 1.95 1.96 2.36 1.90 2.03
OSMF 5423 250 366 1 105 385
b70
critical
shear
rate (sec-I)
Table IB o
Polymer/ G H I J
Property
IZ (g/10 0.50 0.47 0.3 0.64 2.0
min)
Density 0.8630.8600.8700.8550.974
(g/cm')
I,o/IZ 7.30 8.85 6.10 10.5 9.5
Ratio
M",/Mn 2.00 1.91 1.95 2.62 3.1
OSMF lOl 134 58 90 --'
critical
shear
rate (sec-1)
* Unavailable
Examples 1-8
Seven SLEPs were tested as VI improvers in Base
Oil A (FN1365 100N available from Exxon Chemical Co.).
Concentrates of each SLEP (at a 6 wt% polymer concentration)
were prepared by dissolving the polymers in hot (110-120°C) base
oil. The concentrates were then added to the base oil and tested.
Kinematic viscosities (K~ in centistokes (cSt) were determined on
Base Oil A and on each combination of Base Oil A and 0.9 wt% of a
SLEP. KV values were determined at 40°C and 100°C according
to
ASTM D-445. These KV values and the polymer contribution to KV
at 100°C are shown in Table II.
- P 1 er Descri tion
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TahlP TT
Example Polymer KV ~40C KV ~ 100CPolymer KV
Number (cSt) (cSt) Contribution
to
~ 100C cSt
1 * None 19.87 4.009 N A
2 A ** 7.361 3.352
3 C 58.08 8.855 4.846
4 D 45.07 8.160 4.151
F 56.97 ' 9.656 5.647
6 G 54.59 9.684 5.675
7 H 56.31 9.927 5.918
8 ' K ~ 32 05 ~ 6.179 I 2.170 I
* Not an example of the invention ** Nor measured
The KV values shown in Table II indicate that the
5 SLEPs can function as an oil additive and, when added to an
oleaginous composition, yield an improved viscosity at elevated
temperatures such as 100°C. These KV values also indicate the
thickening power of the polymeric additive and can further be used
to calculate amounts to be added to fully formulated oils such as a
5W-30 motor oil
Examyles 9-13
Five SLEPs were tested as VI improvers in a 5W-30
oil formulation. Concentrates (6 wt%) of the SLEPs were prepared
as in Examples 2-8. Table III shows compositions of the oil
formulations. 'I~o different base oils, Base Oil A and Base Oil B
(FN 1243 150N oil, Exxon Chemical Company) were used to prepare
these formulations. The dispersant inhibitor (DI) additive (DI-1)
was 8482-Al (Ethyl Corp). The PPD additive (PPD-1) was a
developmental polyalkylmethacrylate polymer designated as XPD-
194 (Rohm & Haas).
The oil formulations containing a SLEP as a VI
improver were subjected to three tests: KV (at 100°C), as
determined in Examples 1-7; Cold Crank Simulator (CCS), as
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determined at -25°C according to SAE J300 appendix; and High
Temperature Heat Shear (HTHS), as determined at 150°C
according to ASTM D-4741 and ASTM D-4683. Table III also
shows results of these tests.
Exam le Number 9 10 11 12 13
Com onents wt% wt% wt% wt% wt%
Base 011 A 68.97 67.94 68.93 71.29 78.25
Base 011 B 2.49 8.22 8.92 6.23 0.00
DI-I 11.31 11.31 11.31 11.31 11.31
PPD-1 0.30 0.30 0.30 0. 0.30
30
Pol er A Concentrate16.94 -- -- -- -
Pol er C Concentrate-- 12.23 -- -- --
Pol er F Concentrate-- -- 10.54 -- --
Pol er G Concentrate-- -- -- 10.88 --
Pol er H Concentrate-- -- -- -- 10.15
Test Results
KV cSt) 10.69 11.78 10.56 10.66 10.31
CCS cP 3 190 3 250 3,180 3,100 3,220
HTHS cP 3.11 3.18 2.91 3.04 3.00
The data in Table III show that the formulations of
Examples 9-13, all of which contain a SLEP in accordance with the
present invention, meet SAE SH classification criteria for a 5W-30
lubricating oil formulation. The criteria are a KV of 9.1 to 12.5 cSt,
a CCS < 3500 cP and a HTHS > 2.9 cP.
Examples 14-21
Polymers G (ethylene/octene copolymer) and D
(ethylene/propylene/ethylidene norbornene terpolymer)were
evaluated in 5W-30 (Examples 14, 15, 18 and 19) and lOW-30
(Examples 16, 17, 20 and 21) oil formulations prepared from
solvent neutral (SN) and hydrocracked (HC) base oils. The SN base
oils were Base Oils A and B. The HC base oils were available from
Table III
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Chevron USA Products Company as 1008 RLOP oil (Base Oil C)
and 2408 RLOP oil (Base Oil D). The DI (DI-2) was ParaminsT"'
PDN2977 and the PPD was PPD-1. Polymers G and D were added
as 6 wt% concentrate as in Examples 2-8. Table IV shows
component amounts and test results using the same tests as in
Examples 9-13. SAE SH classification criteria for a l OW-30
lubricating oil formulation are the same as those for a 5W-30
formulation except that CCS is determined at -20°C.
a a
Example 14 15 16 17 18 19 20 21
Number
Formulation5W-30 5W-30lOW- lOW- 5W-30 5W-30lOW- lOW-
~.pe SN HC 30 30 SN HC 30 30
SN HC SN HC
Com onentswt% wt% wt% wt% wt% wt% wt% wt%
Base O11 74.84 -- 0.07 -- 78.71 -- 7.03 --
A
Base Oil 3.65 -- 82.10 -- -- -- 72.15 --
B
Base Oil -- 74.40-- 48.23-- 77.59-- 53.03
C
Base 011 -- 4.44 -- 33.51-- 0.17 -- 25.42
D
D!-2 9.91 9.91 9.91 9.91 9.91 9.91 9.91 9.91
PPD-1 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20
Polymer 11.40 11.047.72 8.15 -- -- -- --
G
Concentrate
Polymer -- -- -- -- 11.17 12. 10.71 11.44
D I4
Concentrate
Test Results
KV cSt) 10.65 10.5210.65 10.489.24 9.55 10.78 10.49
CCS (cP) 3,210 3,365-- -- 3,600 3,600-- --
at -
25C
CCS (cP) -- -- 3.145 2,760-- -- 3,245 2,770
at -
20C
HTHS (cP) 2.91 2.81 2.94 2.92 2.83 2.76 3.20 3.01
The data in Table IV show that both polymers work
well with Base Oils A, B, C and D in terms of SAE SH classification
T bl IV
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. ~ ~ CA 02248368 2004-O1-12
criteria for l OW-30 lubricating oil compositions. In Base Oil A,
Polymer G meets all SAE SH classification criteria for 5W-30
lubricating oil compositions whereas in Base Oil B, Polymer G
meets all criteria but HTHS. In Base Oils A and B, Polymer D
meets only the 5W-30 KV criterion. It is believed that a skilled
artisan could readily optimize the formulations for Examples 15,
18 and 19 to meet all SAE SH criteria for 5W-30 formulations.
Examples 22-25
Examples 14-21 were replicated save for using only
Base Oils C and D , changing the DI to either Hitec"'M 1117 (DI-
3)(Examples 22 and 24), obtained from Ethyl Corp., or OLOA~
92508 XA1736 (DI-4) (Examples 23 and 25), obtained from Oronite
I5 Company, and changing the PPD (PPD-3) to a dialkyl fumarate
commercially available as Paramins Paraflow~'~' 392 from Exxon
Chemical Company. Component amounts and test results are
shown in Table V.
Table V
Exam le Number22 23 24 25
Formulation 5W-30 5W-30 lOW-30 IOW-30
a
Com onents wt9b wt95 wt96 wtr6
Base Oil C 72.40 72.69 43.13 34.41
Base Oil D 5.17 6.02 37.81 48.28
DI-3 10.84 - 10.85
DI-4 -- 8.76 -- 8.75
PPD-3 0.20 0.20 0.20 0.20
Polymer G 11.39 12.34 8.01 8.75
Concentrate
Test Results
KV cSt I0.67 10.53 10.56 10.43
CCS cP) at 3 130 2 960 -- --
-25C
CC5 (cP at -- 2 700 2.760
-20C
HTHS cP 3.I1 3.08 3.16 3.14
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The data shown in Table V show that the
substantially Iinear ethylene polymers of the present invention can
meet both 5W-30 and lOW-30 SAE SH classification criteria and
function as VI improvers for a lubricating oil.
Examples 26-28
The procedure of Examples 1-7 was replicated save
for using Polymer G in admixture with one of three other polymers
in amounts as shown in Table VII. The three other polymers were
Polymer D (Example 26), an EP copolymer commercially available
from Exxon Chemical as Paratone'''"' 8452 (Example 27) and a
styrene block polymer commercially available from Shell Chemical
as ShellVisT"' 250 (Example 28). KV values, determined at 40°C
and 100°C and the polymer contribution to the KV at 100°C, all
as
determined in Examples 1-7, are also shown in Table VI together
with the results for Example 1.
~r~h1 P V1T
Example Component Weight KV KV ~ Polymer
~
Number Percen- 40C 100C KV
tage (cSt) (cSt) Contribu-
tion
100C (cSt)
1* Base 011 A 100 19.87 4.009 N A
26 Base Oil A 99.1 48.78 8.802 4.793
Polymer G 0.36
Pol er D 0.54
27 Base Oil A 99.1 65.23 11.24 7.231
Polymer G 0.36
ParatoneT~" 0.54
8452
28 Base Oil A 99.1 47.45 8.687 4.678
Polymer G 0.36
ShellVisTM 0.54
250
* Not an example of the invention
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The data presented in Table VI demonstrate that a
SLEP, particularly an EPDM SLEP, can be blended with other
polymers and still function as an effective oiI additive by imparting
improved viscosity at elevated temperatures.
Examules 29-32
Examples 22-25 were replicated save for
substituting blends of Polymer G and an additional polymer for
Polymer G. The additional polymers were a polymethacrylate
polymer, commercially available from Rohm & Haas as AcryloidT"'
954 (Example 29), an ethylene/propylene/hexadiene terpolymer,
commercially available from DuPont Dow Elastomers L.L.C. as
Nordel~ 4523 (Examples 30 and 32), and an ethylene/propylene/-
hexadiene terpolymer, commercially available from DuPont Dow
Elastomers L.L.C. as Nordel~ 4549 (Example 31). The AcryloidT"'
954 was prepared and added as a 40% concentrate in hot oil. The
Nordel~ 4523 and the Nordel~ 4549 were, like Polymer G,
prepared and added as 6% concentrates in hot oil. Component
amounts and test results are respectively shown in Tables VIIA
and VIIB.
T~hIP ~T11A
Exam le No. 29 30 31 32
Formulation 5W-30 5W-30 5W-30 lOW-
30
Com onents Wth
Base Oil C 76.13 74.04 76.56 35.21
Base Oil D 1.89 0.80 0.05 45.80
DI -3 10.84 10.84 10.85 N A
DI -4 N A N A N A 8.75
PPD - 3 0.20 0.20 0.20 0.02
Pol er G Concentrate9.85 5.67 4.93 6.02
Ac loid'~"' 954 1.09 N A N A N A
NordelT"" 4523 N A 8.45 N A 4.03
NordelT"' 4549 ~ N/A ~ N/A ~ 7.42I N/A
I
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Tahlc~ VTTR
Exam le No. 29 30 31 32
Test Results
KV, cSt 10.76 10.58 10.46 10.57
CCS, cP, at -25C 3.170 3,330 3,230 N/A
CCS, cP, at -20C N/A N/A N/A 2,825
HTHS, cP 3.08 3.06 3.06 3.11
The data presented in Table VII (A and B)
demonstrate that polymer blends incorporating a SLEP can
function as VI modifiers in lubricating oil compositions that meet
5W-30 and lOW-30 SAE SH classification criteria.
Examples 33-36
Examples 22-25 were replicated using DI-3, either
PPD-3 (Examples 34 and 36)or PPD-1 (Examples 33 and 35), and
concentrates of either Polymer G (Examples 33 and 34) or Polymer
J (Examples 35 and ~36) . In addition, physical property testing
included a Scanning Brookfield (SB) temperature, determined at
30,000 centipoise (cP) according to ASTM D-5133. SAE SH criteria
for a 5W-30 formulation include a SB temperature of -30°C.
Component amounts and Test results are shown in Tables VIVA
and VIIIB.
TahlP VIVA
Exam le No. 33 34 35 36
Formulation 5W-30 5W-30 5W-30 5W-30
Components/
Wt%
Base 011 C 72.44 72.40 75.71 75.72
Base Oil D 5.14 5.17 0.56 0.56
DI -3 10.85 10.84 10.86 10.86
PPD -1 0.20 N/A 0.20 N/A
PPD -3 N/A 0.20 N/A 0.20
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Tahlp VTTTR
Exam le No. 33 34 35 36
Polymer G 11.38 11.39 N/A N/A
Concentrate
Polymer J N/A N/A 12.67 12.66
Concentrate
Test Results
KV, cSt 10.76 10.58 10.43 10.43
CCS, cP 3,170 3, 330 3, 3, 570
570
HTHS, cP 3.08 3.06 3.01 3.01
Sg, ~C -26.1 -30.1 -35.3 -35.5
The data in Table VIII show that improved low
temperature viscosities are obtained with PPDs that incorporate a
dialkyl furmarate (Examples 34 and 36) although the effect is more
pronounced with an ethylene octene copolymer (Example 34) than
with an EP copolymer (Example 36) for which either PPD produced
satisfactory results. As all other criteria for a SAE SH 5W-30
classification are met by the formulation of Example 33, a skilled
artisan should be able to modify the formulation of Example 33 to
meet the SB criterion as well.
Examples 37 and 38
The procedure of Examples 1-7 was replicated
using Polymer H, both sheared (Example 38) and unsheared
(Example 37), and Base Oil A. Polymer H had an Iz of 1.72 g/ 10
minutes (min) before shearing and 4.20 g/ 10 min after shearing.
The polymer was sheared in a twin rotor, high speed mixer (Haake)
at 200 revolutions per minute (rpm) for 20 min at 250°C. Other
known mechanical devices such as an extruder could have been
used in place of the high speed mixer. For each example, a Shear
Stability Index (SSI) was also determined. SSI is determined
according to a formula where SSI = 100 x (Vo - VS)(Vo-Vb), where V~,
is the KV of the solution before testing at 100°C, VS is the KV of the
solution after testing at 100°C and Vt, is the KV of the base oil. A
low SSI value is regarded as an indication that a polymer-oil
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solution is more shear stable than a polymer-oil solution with a
higher SSI value. The base oil had a KV before testing of 4.009
(Example 1). Example 37 had a V° of 6.55 cSt, a VS of 5.81 cSt and
a SSI of 29.1. Example 38 had a V° of 5.94 cSt, a VS of 5.64 cSt
and a SSI of 15.5.
The data presented in Examples 37 and 38
demonstrates that shearing a SLEP prior to adding it to an oil and
subjecting the resulting polymer-oil solution to shear stability
testing enhances shear stability (lower SSI) of the solution.
Results similar to those shown in Examples 1-38
are expected when the polymer is sheared after formation of the
polymer-oil solution as well as with other SLEPs and oleaginous
materials, all of which are disclosed above.
Example 39
Polymer G was grafted with malefic anhydride using
the procedure described in USP 5,346,963. In particular, Polymer
G was fed into a Werner-Pfleiderer ZSK70 co-rotating twin screw
extruder at a rate of 750 pounds of polymer per hour. The
extruder was operated at an extruder screw speed of 260 rpm and
with the following zone barrel temperatures: Zone 1 = water
cooling; Zone 2 = 370°F (188°C); Zone 3 = 380° F
(193°C); Zone 4 =
430° F (221°C): Zone 5 = 410° F (210°C); Zone 6 =
410°F (210°C);
Zone 7 = 410° F (210°C): Zone 8 = 430° F
(221°C); Zone 9 = 410° F
(210°C); Zone 10 = 345° F (174°C); Zone 11 = 345°
F (174°C); and
Die = 360° F ( 182°C) to provide a polymer melt temperature
of
446° F (230°C). The malefic anhydride (MAH) was fed at the end
of
Zone 1 of the extruder through an injection nozzle by a metering
pump at a rate of 14.5 pounds per hour. The peroxide,
LUPERSOLT"' 130, (2,5-di(t-butyl peroxy)hexyne-3 manufactured
and sold by Atochem), was fed into the end of Zone 4 of the
extruder through an injection nozzle by a metering pump at a rate
of 1.5 pounds per hour. The extruder was maintained at a
vacuum level of >_ 26 inches of mercury to facilitate devolatization
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of solvent, unreacted MAH and other contaminates. The percent of
incorporation of MAH into polymer G was 1.2 %. Output from the
extruder was pelletized via underwater pelletization at a
temperature of 60° F (16°C).
The MAH-grafted SLEP was then blended and
reacted with a developmental mono-functional amine terminated
polybutylene oxide compound that had a MW of 1500 and was
prepared by The Dow Chemical Company. The blending and
reaction occurred in a Werner-Pfleiderer ZSK-30 co-rotating twin
screw extruder operated at a screw speed of 150 rpm, a
throughput of 20 pounds/hour and an extrusion temperature of
190°C. The amine compound was added to the grafted polymer in
a ratio of amine compound to polymer of 0.15 to 1.
The resulting grafted and reacted polymer was
tested as a VI improver using the same base oil and procedures as
in Examples 1-8. The KV values were as follows: 60.45 cSt at
40°C and 9.706 cSt at 100°C. The polymer contribution to KV at
100°C was 5.611 cSt.
Example 39 shows that a SLEP, when grafted with
an unsaturated organic compound, such as malefic anhydride, and
then further reacted with a functionalizing compound, such as an
amine-terminated compound, provide satisfactory results when
used as a VI improver for an oleaginous composition.
Examples 2-39 all show that adding a SLEP
improves oleaginous composition VI. Other oleaginous
composition properties can be optimized by formulation variations.
Similar results are expected with other SLEPs, unsaturated organic
compounds and functionalizing compounds, all of which are
disclosed above.
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