AGENTS

This application claims the benefit of U.S. Provisional Application No. 60/024,913 filed August 30, 1996 and U.S. Provisional Application No. 60/013,052 filed March 8, 1996.

This invention relates generally to oleaginous compositions that contain at least one ethylene /alpha-olefin (α-olefin) interpolymer 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 maleic 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.

Indicators of VI viscometric performance under actual use conditions include thickening power, shear stability, and chemical and thermal oxidative stability, all of which are related to

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, polyalkylmeth acrylate s, and ethylene/α-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. 10W-30), those that meet both high and low 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.

Summarv 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, I ₁ 0/I2. ≥ 5.63; (ii) a MWD, M _w /M _n , defined by an equation wherein M _w /M _π ≤ U10/I2) - 4.63; and (iii) a critical shear rate at onset of surface melt fracture (OSMF) of at least 50 percent

(%) greater than the critical shear rate at OSMF of a linear olefin polymer having a similar and M /M _n .

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 (I ₂ ) .

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 O.Ol 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

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 /α-olefin copoiymer or diene modified ethylene /α-olefin copoiymer.

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 α-olefin of 3 to 20 carbon atoms (C3-C20). Illustrative α-olefins include propylene, 1 -butene, 1 -hexene, 4- methyl- 1-pentene, 1 -heptene, 1 -octene and styrene. The α-olefin is desirably has a C3-C10 α-olefin. Preferred copolymers include EP and ethylene- octene. Illustrative terpolymers include an ethylene/propylene/octene terpolymer as well as terpolymers of ethylene, a C3-C20 α-olefin and a diene such as dicyclopentadiene, 1 ,4-hexadiene, piperylene or 5-ethylidene-2-norbornene.

The substantially linear ethylene α-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, relevant portions of both being incorporated herein by reference. USP 5,272,236 (column 5, line 67 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- phenyDborane. Specific catalyst complexes are discussed in USP 5,272,236 at column 6, line 57 through column 8, line 58 and in USP 5,278,272 at column 7, line 48 through column 9, line 37. The teachings regarding the catalyst complexes in general and these specific complexes are incorporated by reference.

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 I ₂ and melt flow ratio (MFR or I10/I2). The interpolymers desirably have an I ₂ (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 I10/I2 ratio serves as an indication of the degree of LCB such that a larger I10/I2 ratio equates to a higher degree of LCB in the polymer.

A further distinct characteristic of a SLEP is MWD (Mw/M _n or "polydispersity index "), as measured by gel permeation chromatography (GPC). M _w /M _n is defined by the equation:

The MWD is desirably > 0 and < 5, especially from 1.5 to 3.5, and preferably from 1.7 to 3.

A homogeneously branched SLEP surprisingly has a MFR that is essentially independent of its MWD. 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 having a critical shear rate at OSMF of at least 50 % greater than the critical shear rate at the OSMF of a linear olefin polymer that has a like I ₂ and M _w /M _n .

SLEPs that meet the aforementioned criteria include, for example, ENGAGE™ 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 or esters of such acids. Representative compounds include maleic, fumaric, acrylic, methacrylic, itaconic, crotonic, α-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

tertiary amine). Representative examples include vinyl pyridine and vinyl pyrrolidone. Maleic anhydride is the preferred unsaturated organic compound.

The unsaturated organic compound content of a grafted SLEP is > 0.01 wt%, and preferably > 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 < 10 wt %, preferably < 5 wt%, more preferably < 2 wt%.

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, the relevant teachings of which are incorporated into and made a part of this application by reference. In USP 3,236,917, a polymer, such as an EP copoiymer, is introduced into a two-roll mixer and mixed at a temperature of 60° Centigrade (°C}. The unsaturated organic compound, such as maleic anhydride, is then added along with a free radical initiator, such as benzoyl peroxide, and the components are mixed at 30°C until grafting 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

monomers to be grafted are used in a concentration of 0.01-0.5, preferably from 0.05-0.25, wt%, based on ethylene polymer weight.

An alternative and preferred method of grafting is taught in USP 4,950,541, the relevant teachings of which are incorporated herein by reference. 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 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 relevant teachings of which are incorporated herein by reference. 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 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 > 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 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,

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), l-(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, the relevant teachings of which are incorporated herein by reference.

USP 5,401 ,427 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- methylimidazoline, l ,3-bis-(2-aminopropyl)imidazoline, pyrimidine, l-(2-aminopropyl)piperazine, l ,4-bis(2-aminoethyl)piperazine, N,N - dimethyaminopropyl amine, N.N'-dioctylethyl amine, N-octyl-N - methylethylene diamine, and 2-methyl- l-(2-aminobutyl)piperazine. 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- hydroxyethyDethylene diamine, l-(2- hydroxyethyl)-piperazine, monohydroxy-propyl-substituted diethylene triamine,

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, improve(s) 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

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 and mixed paraffinic-naphthenic types, oils derived from coal or shale, poly(α-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 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 that is incorporated herein by reference.

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, 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 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 C8 mono and dicarboxylic acids. The additives may be introduced as concentrated solutions or dispersions in oil or without dilution.

In preparing lubricating oil formulations, additives are commonly introduced as 5 to 80 wt% active ingredient concentrates in oil. The use of concentrates makes handling of the various materials less difficult and facilitates solution or dispersion of the additives in the formulation.

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 any or all 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 % ciystallinity, preferably < 3 and more preferably < 1 , but > 0, % crystallinity), any conventional PPD may be used provided the onset of crystallization (T _c ) for wax(es) contained in the oleaginous material is not within a range for T _c 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

copolymers used as PPDs are suitably prepared as described in USP 4,839,074, the relevant teachings of which are incorporated herein by reference.

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 > 70 mole % of 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 C ₂ o aliphatic alcohols, more preferably Cβ to C20 aliphatic alcohols.

It is believed that a semicrystalline SLEP that works well with a di-n-alkyl fumarate /vinyl acetate copoiymer has a peak crystallization temperature (as determined by differential scanning calorimetry (DSC)) that differs from that of wax(es) contained in the oleaginous material such that the SLEP and wax(es) 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 copoiymer 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,

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 5 to 15 wt% dry polymer for thickening or gelling applications.

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 maleic anhydride grafted SLEP (prepared as described above and in column 3, line 67 through column 4, line 24 of USP 5,346,963) 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 maleic 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

ethylenically unsaturated carboxylic acid material, such as maleic anhydride, onto an ethylene/α-olefin polymer, such as an EP copoiymer, and then reacting a polyamine with the grafted polymer); USP 4, 160,739 (column 6, lines 35-52, relating to post- reaction of carboxyl groups provided by maleic 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 maleic anhydride grafted ethylene/α-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, line 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, lines 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 Cβ-Ciβ alcohol in a solution of a polyolefin polymer). The relevant teachings of these patents are incorporated herein by reference.

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.

Examples

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:

A. An ethylene /octene copoiymer (ethylene content of

61.7 wt%) commercially available from DuPont Dow Elastomers L.L.C. as EG 8200.

B. An ethylene/butene copoiymer commercially available from Exxon Chemical Company as EXACT™ 4024.

C. An ethylene /octene copoiymer (ethylene content of 68.2 wt%) commercially available from DuPont Dow Elastomers L.L.C. as EG 8100.

D. A developmental ethylene/propylene/ethylidene norbomene terpolymer (ethylene content of 57 wt%) made by DuPont Dow Elastomers L.L.C.

E. An EP copoiymer commercially available from Mitsui Petrochemical as TAFMER™ P-0480.

F. An ethylene/octene copoiymer (ethylene content of 64.7 wt%) commercially available from DuPont Dow Elastomers

L.L.C. as EG 8150.

G. An ethylene/octene copoiymer (ethylene content of 61.0 wt%) commercially available from DuPont Dow Elastomers L.L.C. as DEG 8180.

H. A developmental EP copoiymer (ethylene content of 53.1 wt%) made by DuPont Dow Elastomers L.L.C.

1. An EP copoiymer commercially available from

Mitsui Petrochemical as TAFMER™ P-0480.

J. A developmental EP copoiymer (ethylene content of 34.7 wt%) made by DuPont Dow Elastomers L.L.C.

K. A developmental ethylene /styrene copoiymer

(ethylene content of 60 wt%) made by The Dow Chemical Company.

Tables IA and IB contain physical property information for primary polymers A-K.

Table IB - 1 Polymer Description

* Unavailable Examples 1-8

Seven SLEPs were tested as VI improvers in Base Oil A (F 1365 100N available from Exxon Chemical Co.).

Concentrates of each SLEP (at a 6 wt% polymer concentration) were prepared by dissolving the polymers in hot (1 10- 120°C) base oil. The concentrates were then added to the base oil and tested. Kinematic viscosities (KV) 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.

Table II

* Not an example of the invention ** Nor measured

The KV values shown in Table II indicate that the 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

Examples 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. Two different base oils, Base Oil A and Base Oil B (FN1243 150N oil, Exxon Chemical Company) were used to prepare these formulations. The dispersant inhibitor (DI) additive (DI- 1) was 8482-A1 (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

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.

Table III

Example Number/ 9 10 11 12 13

Components wt% wt% wt% t% wt%

Base Oil A 68.97 67.94 68.93 71.29 78.25

Base Oil B 2.49 8.22 8.92 6.23 0.00

DM 11.31 11.31 11.31 11.31 11.31

PPD- 1 0.30 0.30 0.30 0.30 0.30

Polymer A Concentrate 16.94 — — -- --

Polymer C Concentrate — 12.23 — — —

Polymer F Concentrate — — 10.54

Polymer G Concentrate — -- __ 10.88

Polymer H Concentrate — — __ 10.15

Test Results

KV (cSt) 10.69 1 1.78 10.56 10.66 10.31

CCS (cP) 3, 190 3,250 3, 180 3, 100 3,220

HTHS (cP) 3.1 1 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 copoiymer) and D (ethylene/propylene/ethylidene norbornene terpolymer)were evaluated in 5W-30 (Examples 14, 15, 18 and 19) and 10W-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

Chevron USA Products Company as 100R RLOP oil (Base Oil C) and 240R RLOP oil (Base Oil D). The DI (DI-2) was Paramins™ 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 10W-30 lubricating oil formulation are the same as those for a 5W-30 formulation except that CCS is determined at -20°C.

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

criteria for 10W-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™ 1 1 17 (DI- 3) (Examples 22 and 24), obtained from Ethyl Corp., or OLOA 9250R XA1736 (DI-4) (Examples 23 and 25), obtained from Oronite 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

Example Number 22 23 24 25

Formulation Type 5W-30 5W-30 10W-30 10W- 30

Components wt% wt% wt% wt%

Base Oil C 72.40 72.69 43.13 34.41

Base Oil D 5.17 6.02 37.81 48.28

Dl-3 10.84 10.85 __

Dl-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) 10.67 10.53 10.56 10.43

CCS (cP) at -25°C 3, 130 2,960 __ __

CCS (cP) at -20°C ._ __ 2,700 2,760

HTHS <cP) 3.1 1 3.08 3.16 3.14

The data shown in Table V show that the substantially linear ethylene polymers of the present invention can meet both 5W-30 and 10W-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 copoiymer commercially available from Exxon Chemical as Paratone™ 8452 (Example 27) and a styrene block polymer commercially available from Shell Chemical as ShellVis™ 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.

Not an example of the invention

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 oil additive by imparting improved viscosity at elevated temperatures.

Examples 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 Acryloid™ 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 Acryloid™ 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 VILA, and VIIB.

Table VIIB

Example No. 29 30 31 32

Test Results

KV, cSt 10.76 10.58 10.46 10.57

CCS, cP, at -25°C 3, 170 3,330 3,230 N/A

CCS, cP, at -20°C N/A N/A N/A 2,825

HTHS, cP 3.08 3.06 3.06 3.1 1

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 10W-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 VIIIA and VIIIB.

Table VIIIA

Table VIIIB

Example 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 3,570 3,570

HTHS, cP 3.08 3.06 3.01 3.01

SB, °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 copoiymer (Example 34) than with an EP copoiymer (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 I ₂ 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 (V ₀ - V _s )(V ₀ -Vb), where V„ is the KV of the solution before testing at 100°C, V _s is the KV of the solution after testing at 100°C and Vb is the KV of the base oil. A low SSI value is regarded as an indication that a polymer-oil

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 ₀ of 6.55 cSt, a V _s of 5.81 cSt and a SSI of 29.1. Example 38 had a V _D of 5.94 cSt, a V _s 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 maleic 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 1 1 = 345° F (174°C); and Die = 360° F (182°C) to provide a polymer melt temperature of 446° F (230°C). The maleic 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, LUPERSOL™ 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

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 M _w 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 5.61 1 cSt.

Example 39 shows that a SLEP, when grafted with an unsaturated organic compound, such as maleic 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.