INTERPOLYMERS CONTAINING LUBRICATING OIL COMPOSITION

Abstract: Lubricating oil compositions comprising substantially random interpolymers comprising (1) ethylene, (2) one or more vinylic monomers selected from the group consisting of aromatic, hindered aliphatic, and cycloaliphatic vinylic monomers, and (3) one or more olefinic monomers having from 3 to about 20 carbon atoms useful as viscosity index improving agents.

Description: INTERPOLYMERS CONTAINING LUBRICATING OIL COMPOSITION FIELD OF THE INVENTION The present invention pertains to lubricating oil compositions comprising interpolymers containing (1) ethylene; (2) one or more vinylic monomers selected from the group consisting of aromatic, hindered aliphatic and cycloaliphatic vinylic monomers, and (3) one or more polymerizable C 3 to C 20 olefmic monomers. These polymers serve as viscosity improving agents. BACKGROUND OF THE INVENTION The viscosity of lubricating oils, particularly the viscosity of mineral oil based lubricating oils, is generally dependent upon temperature. As the temperature of the oil is increased, the viscosity usually decreases. The function of a viscosity improver in lubricating oil compositions is to reduce the extent of the decrease in viscosity as the temperature is raised or to reduce the extent of the increase in viscosity as the temperature is lowered, or both. Thus, a viscosity improver ameliorates the change of viscosity of an oil containing it with changes in temperature. The fluidity characteristics of the oil are improved. Viscosity improvers are usually polymeric materials and are often referred to as viscosity index improvers. Many patents relating to viscosity improvers are discussed by Ranney (Ed.), "Lubricant Additives", Noyes Data Corp. (1973), pp 93- 145. A number of hydrogenated alkenylarene-conjugated diene interpolymers are known in the pπor art to be effective viscosity index (VI) improvers for lubricating oils. U.S. Pat. Nos. 3.554,911 (Schiff et al); 3,630.905 (Sorgo); and 3,772.169 (Small et al.) are concerned with the use of hydrogenated random butadiene-styrene copolymers as VI improvers for lubricating oils. These copolymers are prepared by the copolymeπzation, using conventional techniques, of butadiene and styrene in the presence of a randomizing agent and subsequently, the copolymers are partially hydrogenated. U.S. Patent 2,336,195 (Sparks et al.) relates to improving viscosity characteπsucs of hydrocarbon oils by addition of normal mono-olefin polymers. U.S. Patent 3,772,196 (St. Clair et al.) descπbes lubricating oils for internal combustion engines that have wide temperature operating characteristics. The composition contains a combination of a 2-block copolymer comprising a first block of an alkenyl arene, e.g. styrene, and a second essentially completely hydrogenated polyisoprene block and certain pour point depressants in a lubπcant stock having viscosity index of at least 85. Many vmyl aromatic monomer-diene copolymers of the pπor art are tapered block copolymers. The interpolymers of the instant invention are random interpolymers The geneπc class of mateπals covered by alpha-olefin/hmdered vinylic monomer substantially random interpolymers and including mateπals such as ethylene/vmyl aromatic monomer interpolymers is known in the art For example, substantially random ethylene/styrene interpolymers, including pseudo-random interpolymers as descπbed in EP 415815 A, offer a range of mateπal structures and properties which makes them useful for vaπed applications, including the compatibihzation of blends of polyethylene and polystyrene as descπbed in U.S Patent 5,460,818 Random copolymers of aromatic vinyl monomer and an alpha- olefin having 4 to 12 carbon atoms are descπbed in U.S Patent 5,244,996 Interpolymers of the type now found useful in the lubπcating oil compositions of this invention are descπbed in U.S. Patent 5,872,201. Other patent publications provide limited geneπc reference to terpolymers of ethylene/styrene/alpha-olefm mateπals. Examples in JP 07/278,230 are limited to 2 mole percent or less incorporation of styrene in ethylene/ alpha-olefin copolymers None of these references teaches the use of such polymers as viscosity improving additives for lubπcating oil compositions. Although of utility in their own πght, efforts continue to further expand the applicability of these geneπc interpolymers into lubπcating applications, and especially those based on alpha-olefin/viny c aromatic monomers, such as ethylene/styrene interpolymers. Lubπcatmg applications include use of the polymers as viscosity improvers for lubncatmg oils and as thickeners for lubπcatmg greases. Desired improved or supeπor characteπstics to current state of the art mateπals can include, but are not limited to performance characteπstics such as extended temperature range of application and low temperature performance and improved compatibility with a vaπety of oils of lubπcating viscosity, especially synthetic oils and high viscosity index base stocks. The interpolymers used in the lubπcating oil compositions of this invention are less costly compared to hydrogenated vmyhc aromatic monomer-diene copolymers. The interpolymers of this invention provide an effective technology to address such needs. SUMMARY OF THE INVENTION The present invention relates to lubπcating oil compositions compπsing a major amount of an oil of lubπcating viscosity and a minor, viscosity improving amount, of a substantially random mterpolymer resulting from polymeπz g (1) from about 19.5 to about 98.5 mole percent of ethylene; (2) from about 0.5 to about 60 mole percent of one or more vinylic monomers selected from the group consisting of aromatic, hindered aliphatic, and cycloaliphatic vmy c monomers; and (3) from about 1 to about 80 mole percent of one or more olefmic monomers having from 3 to about 20 carbon atoms. One aspect of the present invention pertains to lubπcating oil compositions compπsing interpolymers compπsing (1) from about 19.5 to about 98.5 mole percent of ethylene (2) from about 0.5 to about 60 mole percent of a vinylic monomer selected from the group consisting of aromatic and hindered aliphatic, and cycloaliphatic vmy c monomers, and (3) from about 1 to about 80 mole percent of one or more C 3 to C 20 olefmic monomers. In one embodiment, the interpolymers of the present invention can compπse any three such monomers enumerated herein; these interpolymers can compπse the three enumerated polymeπzable monomers, with the third monomer (3) being one C 3 to C 2 o olefmic monomer. The interpolymers of the present invention can be free of any component, compound or substituent not specifically enumerated herein when desired. Also, the present invention can be free of any component, compound or substituent even though such component, compound or substituent was oπgmally believed to be a pan of the invention. The interpolymers of the present invention provide an improvement in one or more of the properties such as viscosity index in lubπcating oils and improved compatibility with a wide vaπety of oils of lubπcating viscosity, especially high viscosity index oils and particularly synthetic oils. DETAILED DESCRIPTION OF THE INVENTION The term "terpolymer" is used herein to indicate a polymer wherein three different monomers are polymeπzed to make the terpolymer. The term "mterpolymer" is used herein to indicate a polymer wherein three or more different monomers are polymeπzed to make the mterpolymer. The term "substantially random" in the substantially random mterpolymer compπsing ethylene, one or more vmyhc aromatic monomers or hindered aliphatic vinylic monomers, and one or more C 3 to C 20 olefmic monomers as used herein means that the distπbution of the monomers of said mterpolymer can be descπbed by the Bernoulli statistical model or by a first or second order Markovian statistical model, as descπbed by J. C. Randall in POLYMER SEQUENCE DETERMINATION, Carbon-13 NMR Method, Academic Press, New York (1977), pp. 71-78. Preferably, the substantially random mterpolymer does not contain more than 15 percent of the total amount of vmyhc aromatic monomer in blocks of vmy c aromatic monomer of more than 3 units. More preferably, the mterpolymer is not characteπzed by a high degree of either isotacticity or syndiotacticity. This means that in the Carbon-13 NMR spectrum of the substantially random mterpolymer the peak areas corresponding to the mam chain methylene and methme carbons representing either meso diad sequences or racemic diad sequences should not exceed 75 percent of the total peak area of the mam chain methylene and methme carbons. Any numeπcal values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process vaπable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc. are expressly enumerated m this specification. For values which are less than one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropπate. These are only examples of what is specifically intended and all possible combinations of numeπcal values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner The interpolymers used in the lubπcating oil compositions of the present invention compπse at least three different monomers, (1) from about 19 5 to about 98.5, preferably from about 25 to about 95, more preferably from about 30 to about 94 mole percent of ethylene; (2) from about 0 5 to about 60, preferably from about 1 to about 55, more preferably from about 1 to about 50 mole percent of one or more aromatic vmyhc monomers or hindered aliphatic vmyhc monomers, and (3) from about 1 to about 80, preferably from about 4 to about 65, more preferably from about 5 to about 50 mole percent of one or more C 3 to C olef monomers It is to be understood that the total amount of (1), (2) and (3) is 100 mole percent. The weight average molecular weight ( M w ) of the interpolymers of the present invention is usually greater than about 10,000, preferably from about 50,000 to about 700,000, more preferably from about 80,000 to about 350,000. Molecular weights of the hydrocarbon polymer are determined using well known methods descπbed in the literature. Examples of procedures for determining the molecular weights are gel permeation chromatography (GPC) (also known as size-exclusion chromatography) and vapor phase osmometry (VPO). These and other procedures are descπbed in numerous publications including P.J. Flory, "Pπnciples of Polymer Chemistry", Cornell University Press (1953), Chapter VII, pp. 266-316, "Macromolecules, an Introduction to Polymer Science", F.A. Bovey and F.H. Wmslow, Editors, Academic Press (1979), pp. 296-312, and W.W. Yau, JJ. Kirkland and D.D. Bly, "Modern Size Exclusion Liquid Chromatography", John Wiley and Sons, New York, 1979. Molecular weight values refeπed to herein are direct molecular weights determined using GPC with mulϋangle light scatteπng and refractive index for detection. Such procedures are descπbed in the literature, for example m Barth et al., Chemical Analysis, Vol. 113, "Modern Methods of Polymer Characteπzation", John Wiley & Sons, (1991). Other procedures that can be used include GPC employing polystyrene standards. It is particularly preferred that the mterpolymer of this invention is a terpolymer. Especially preferred is the terpolymer wherein component (2) is an aromatic vinyhc monomer, more preferably styrene, and component (3) is an alpha olef having from 3 to about 12 carbon atoms, more preferably one or more olefmic monomers selected from the group consisting of propylene, butene-1, 4-methyl-l- pentene, pentene-1, hexene-1 and octene-1. The present invention particularly concerns the following terpolymers: ethylene/styrene/propylene; ethylene/styrene/4-methyl-l-pentene; ethylene/styrene/ hexene-1; ethylene/styrene/octene-1; and ethylene/styrene/1-butene. Suitable alpha-olefms, or combinations of alpha-olefms, which can be employed as olefmic monomer(s) (3) include for example, those containing from 3 to about 20, preferably from 3 to about 12, more preferably from 3 to about 8 carbon atoms. Suitable olefmic monomers which can be employed as olefinic monomer(s) (3) include strained πng olefms such as norbornene. Particularly suitable as olefmic monomer(s) (3) include propylene, 4-methyl-l-pentene, pentene-1, hexene-1 , octene- 1 and butene-1. The olefinic reactant (3) does not include hindered aliphatic and cycloaliphatic olefins as defined herein for reactant (2) Suitable vmyhc aromatic monomers for use as component (2) include, for example, those represented by the following formula: Ar I (CH 2 ) n R'- C=CH 2 wherein R 1 is selected from the group of radicals consisting of hydrogen and hydrocarbyl groups, preferably alkyl or aryl groups, especially alkyl radicals containing from 1 to about 4 carbon atoms and more preferably hydrogen or methyl, and Ar is a phenyl group or a phenyl group substituted with from 1 to 3 substituents selected from the group consisting of halo, Cι- -alkyl, and haloalkyl; and n has a value from zero to about 6, preferably from zero to about 2, more preferably zero. Exemplary monovinyhc aromatic monomers include styrene, vmyl toluene, alpha- methylstyrene, t-butyl styrene, chlorostyrene, including all isomers of these compounds, and the like. Particularly suitable such monomers include styrene and lower alkyl- or halogen-substituted deπvatives thereof. Prefeπed monomers include styrene, alpha-methyl styrene, the lower alkyl- or phenyl-πng substituted deπvatives of styrene, such as ortho-, meta-, and para-methylstyrene, the πng halogenated styrenes, para- vinyl toluene or mixtures thereof, and the like. A more preferred monovinyhc aromatic monomer is styrene. Suitable "hindered aliphatic or cycloaliphatic vmyhc monomers" for use as components (2) include addition polymeπzable vinyhc monomers coπespondmg to the following formula- R' R' - C =CH, wherein R 1 is selected from the group of radicals consisting of hydrogen and hydrocarbyl groups, preferably alkyl or aryl groups, especially alkyl radicals containing from 1 to about 4 carbon atoms and more preferably hydrogen or methyl; and R is a steπcally bulky, aliphatic substituent of up to 20 carbons; or alternatively 1 1 R and R" together form a πng system. By the term "steπcally bulky" it is meant that the monomer beaπng this substituent is normally incapable of addition polymeπzation by standard Ziegler-Natta polymeπzation catalysts at a rate comparable with ethylene polymeπzations. Preferred hindered aliphatic or cycloaliphatic vmyhc monomers are those in which one of the carbon atoms beaπng ethylenic unsaturation is tertiary or quaternary substituted. Examples of such substituents include cyclic aliphatic groups such as cyclohexyl, cyclohexenyl, cyclooctenyl, or πng alkyl or aryl substituted deπvatives thereof, tert-butyl, norbornyl, and the like. Most preferred hindered aliphatic or cycloaliphatic vinyhc compounds are vinyl cyclohexane and the vaπous isomeπc vinyl-πng substituted deπvatives of cyclohexene and substituted cyclohexenes, and 5-ethyhdene-2-norbomene. Especially suitable is vinyl cyclohexane. The substantially random interpolymers of the present invention can be prepared as descπbed in EP-A-0,416,815 (Stevens et al.) which is incorporated herein by reference in its entirety. Prefeπed operating conditions for such polymenzation reactions are pressures from atmospheπc up to 3000 atmospheres and temperatures from - 30° C to 200° C Polymeπzations and unreacted monomer removal at temperatures above the autopolymeπzation temperature of the respective monomers may result in formation of some amounts of homopolymer polymeπzation products resulting from free radical polymeπzation. While prepaπng the substantially random interpolymers of the present invention as will be descπbed hereinafter, an amount of atactic vmyhc aromatic homopolymer may be formed due to homopolymeπzation of the vinyhc aromatic monomer. However, NMR indicates polystyrene may be present in the styrene monomer and is not always generated duπng the polymeπzation reaction Thus, the presence of polystyrene the polymer may be avoided by use of styrene monomer of suitable puπty The presence of vinyhc aromatic homopolymer is in general not desirable for the purposes of the present invention, often resulting in hazy oil blends. The vmyhc aromatic homopolymer may be separated from the mterpolymer, if desired, by extraction techniques such as selective precipitation from solution with a non-solvent for either the mterpolymer or the vinyhc aromatic homopolymer For example, a polystyrene containing polymer is dissolved in hexane and coagulated in acetone. For the purpose of the present invention it is preferred that the copolymers of this invention are substantially free of vinyhc aromatic homopolymer As used here, "substantially free" means the copolymer contains no amount of viny c aromatic homopolymer that would cause objectionable haze or other incompatibility in a lubπcating oil composition. Preferably, the copolymer is free of vmyhc aromatic homopolymer. Examples of suitable catalysts and methods for prepaπng the substantially random interpolymers of the present invention are disclosed in EP-A-416,815; EP-A-514,828; U.S. Patent No. 5,721,185; U.S. Patent No. 5,470,993; as well as U.S. Patent Nos. 5,055,438; 5,057,475; 5,096,867; 5,064,802; 5,132,380; 5,189,192; 5,321,106; 5,347,024; 5,350,723; 5,374,696; 5,399,635; 5,556,928; 5,703,187 and 5.872,201, all of which patents and applications are incorporated herein by reference. The substantially random interpolymers of the present invention can also be prepared by the methods descπbed by Bradfute et al. in WO 95/32095, by Pannell in WO 94/00500; and in Plastics Technology, p. 25 (September 1992), all of which are incorporated herein by reference in their entirety Further preparative methods which may be applicable for the interpolymers of the present invention have been descπbed the literature Longo and Grassi (Makromol. Chem., Volume 191, pages 2387 to 2396 [1990]) and D'Anniello et al. (Journal of Applied Polymer Science, Volume 58, pages 1701-1706 [1995]) reported the use of a catalytic system based on methylaluminoxane (MAO) and cyclopentadienyltitanium tπchloπde (CpTιCl 3 ) to prepare an ethylene-styrene copolymer. Xu and L (Polymer Prepπnts, Am Chem.SocDiv Polym. Chem.) Volume 35, pages 686,687 [1994]) have reported copolymeπzation using a TιCl4/NdCl 3 /Al(ιBu) 3 catalyst to give random copolymers of styrene and propylene. Lu et al. (Journal of Applied Polymer Science, Volume 53, pages 1453 to 1460 [1994]) have descπbed the copolymeπzation of ethylene and styrene using a TiCL/NdCln/MgCL /Al(Et) 3 catalyst. Sernetz et al. (Macromol. Chem Phys., v 197, pp 1071-1083, 1996) have descπbed copolymeπzation of styrene with ethylene using η 6 -(C 5 (CH 3 ) 4 Sι(CH 3 ) 2 N(tert-C 4 H 9 ))TιCl 2 /methylalummoxane Another suitable method includes the method disclosed for the manufacture of alpha - olefm/vinyl aromatic monomer interpolymers such as propylene/styrene and butene/styrene descπbed in U.S. Pat. No. 5,244,996, assigned to Mitsui Petrochemical Industπes Ltd. All of the above are incorporated herein by reference. Additives such as organic antioxidants (e.g., hindered phenols such as, for example, IRGANOX™ 1010), phosphites (e.g., IRGAFOS™ 168)), both from Ciba- Geigy, UV stabilizers, and the like can also be included in the interpolymers, additive concentrates and lubncating oil compositions of the present invention, to the extent that they do not interfere with the enhanced properties discovered by Applicants. The following examples are illustrative of the polymers used in the lubπcating oil compositions of the invention, but are not to be construed as to limiting the scope of the invention m any manner. All temperatures are m degrees Celsius (°C). Polvmeπzation: In a typical polymeπzation dry hexane (see Table 1) is pressuπzed from a stainless steel hold tank under nitrogen into a dry 1 gal (3.7 L) batch reactor equipped with a magnetically dπven stirnng mechanism A heptane solution of methylalummoxane (120 g, 165.5 mL; 7 wt% Al), which contains 30 mole% zso-butyl groups, is then pressuπzed into the reactor under nitrogen. Freshly distilled styrene and α-olefin (see Tables 1-2) are added, and the homogeneous mixture is thermostated at the desired temperature (see Table 1). Once the desired temperature is reached, the reactor is pressuπzed with the desired amount of ethylene (see Tables 1-2). Finally, a heptane solution of methylalummoxane (34.8 g, 47.7 mL, 7 wt% Al), which contains 30 mole% iso-butyl groups, is mixed with η 6 -(C 5 (CH 3 ) 4 Sι(CH ) 2 N(tert-C 4 H 9 ))TιCl 2 (9.6 mg) to form a homogeneous solution. This solution is added to the reactor under nitrogen withm 5 mm of becoming homogeneous. The polymeπzation reaction is terminated after a given peπod of time (see Table 1) by venting the ethylene from the reactor and pressuπz g the polymer cement from the reactor under nitrogen into zso-propyl alcohol (2 L), to which HC1 (15-25 mL; 18 M) has been added. Polymer Puπfication- The coagulated polymer is collected and πnsed with fresh wo-propyl alcohol (1 L). This process is repeated 2-3 times The coagulated polymer is air dried for 24- 48 h and is then dπed to constant weight at 50° C m a vacuum oven Any remaining aluminum inorganic mateπal is removed by exhaustively centπfugmg a tetrahydrofuran solution (0.1-0.15 g/mL) of the polymer, in which the aluminum inorganic mateπal is insoluble. The polymer is decanted from the insoluble mateπal, coagulated in fresh sø-propyl alcohol, air dπed for 24-48 h, and then dπed to constant weight at 50° C in a vacuum oven. This process is repeated from 2-3 times. Any homopoly styrene present in the polymer is removed by coagulating a tetrahydrofuran solution (0.1-0.15 g/mL) of the polymer in acetone (about 1.5-2 L). The coagulated polymer is then collected by decantation, air dπed for 24-48 h, and then dπed to constant weight at 50°C m a vacuum oven. This process can also be repeated if necessary. If the polymer contains polystyrene homopolymer, the polymer may, if desired, be dissolved hexane and coagulated in acetone, effectively removing 0 polystyrene. The mterpolymer is free from impuπties if a homogeneous solution is formed when a 10 wt% solution of the polymer is made with mineral oil. Table 1 5 (g) - grams (h) - hours (mL) - millihters (psig) - pound per square inch, gauge (hex) - hexene 0 (oct) - octene Table 2 Results: Results are tabulated in Tables 3-4. Table 3 * (Kg mole Ti/h) Compositions of the copolymers of Examples 1-9 (mole %, measured by ! H NMR) and molecular weights, (GPC, (multiangle light scatteπng and refractive index for detection)) are set forth Table 4: Table 4 # differential refractive index Other Additives Additive concentrates and lubπcatmg oil compositions of this invention may contain other additives. The use of such additives is optional and the presence thereof in the compositions of this invention will depend on the particular use and level of performance required. Thus the other additive may be included or excluded. Additive concentrates of this invention typically compπse from about 0.1 % to about 30% by weight of mterpolymer and from about 70% to about 99.9% by weight of a substantially, inert, normally liquid, organic diluent. Lubπcating oil compositions often compπse zinc salts of a dithiophosphoπc acid, often refeπed to as zmc dithiophosphates, zinc O,O-dιhydrocarbyl dithiophosphates, and other commonly used names. They are sometimes refeπed to by the abbreviation ZDP. One or more zinc salts of dithiophosphoπc acids may be present m a minor amount to provide additional extreme pressure, anti-wear and anti- oxidancy performance. Other additives that may optionally be used in the lubπcatmg oils of this invention include, for example, detergents, dispersants, supplemental viscosity improvers, oxidation inhibiting agents, corrosion inhibiting agents, pour point depressing agents, extreme pressure agents, anti-wear agents, color stabilizers, fπction modifiers, and anti-foam agents. Extreme pressure agents and coπosion and oxidation inhibiting agents which may be included in the compositions of the invention are exemplified by chlonnated aliphatic hydrocarbons, organic sulfides and polysulfides, phosphorus esters including dihydrocarbon and tnhydrocarbon phosphites, molybdenum compounds, and the like. Other oxidation inhibiting agents include mateπals such as alkylated diphenyl amines, hindered phenols, especially those having tertiary alkyl groups such as tertiary butyl groups in the position ortho to the phenolic -OH group, and others Such mateπals are well known to those of skill m the art Auxiliary viscosity improvers (also sometimes referred to as viscosity index improvers or viscosity modifiers) may be included in the compositions of this invention. Viscosity improvers are usually polymers, including polyisobutenes, polymethacry c acid esters, hydrogenated diene polymers, polyalkyl styrenes, esteπfied styrene-maleic anhydπde copolymers, hydrogenated alkenylarene- conjugated diene copolymers and polyolefms Multifunctional viscosity improvers, which also have dispersant and/or antioxidancy properties are known and may optionally be used in addition to the products of this invention Such products are descπbed m numerous publications including those mentioned in the Background of the Invention. Each of these publications is hereby expressly incorporated by reference Pour point depressants may be included in the additive concentrates and lubπcating oils descπbed herein Those which may be used are descπbed in the literature and are well-known to those skilled m the art; see for example, page 8 of "Lubπcant Additives" by C.V. Smalheer and R. Kennedy Smith (Lezius-Hiles Company Publisher, Cleveland, Ohio, 1967) Pour point depressants useful for the purpose of this invention, techniques for their preparation and their use are descπbed in U. S. Patent Nos. 2,387.501, 2,015,748, 2,655,479, 1,815,022, 2,191,498, 2,666,748; 2,721,877, 2,721,878; 3,250,715; and 5,707,943 which are expressly incorporated herein by reference for their relevant disclosures. Anti-foam agents used to reduce or prevent the formation of stable foam include sihcones or organic polymers. Examples of these and additional anti-foam compositions are descπbed in "Foam Control Agents", by Henry T. Kerner (Noyes Data Corporation, 1976), pages 125-162. Detergents and dispersants may be of the ash-producmg or ashless type. The ash-producing detergents are exemplified by oil soluble neutral and basic salts of alkali or alkaline earth metals with sulfomc acids, carboxyhc acids, phenols or organic phosphorus acids characteπzed by a least one direct carbon-to-phosphorus linkage. The term "basic salt" is used to designate metal salts wherein the metal is present in stoichiometπc ally larger amounts than the organic acid radical. The relative amount of metal present in "basic salts" is frequently indicated by the expression "metal ratio" (abbreviated MR), which is defined as the number of equivalents of metal present compared to a "normal", stoichiometπc amount. Thus, for example, a basic salt containing twice the amount of metal compared to the stoichiometπc amount, has a metal ratio (MR) of 2. Basic salts and techniques for prepaπng and using them are well known to those skilled in the art and need not be discussed in detail here. Ashless detergents and dispersants are so-called despite the fact that, depending on its constitution, the detergent or dispersant may upon combustion yield a nonvolatile residue such as bone oxide or phosphorus pentoxide; however, it does not ordmaπly contain metal and therefore does not yield a metal-containing ash on combustion Many types are known in the art, and any of them are suitable for use the lubπcants of this invention. The following are illustrative- (1) Reaction products of carboxyhc acids (or deπvatives thereof) containing at least about 34 and preferably at least about 54 carbon atoms with nitrogen containing compounds such as amine, organic hydroxy compounds such as phenols and alcohols, and/or basic inorganic matenals Examples of these "carboxyhc dispersants" are descπbed in Bπtish Patent number 1,306,529 and many U.S patents including the following: 3,163,603 3,399,141 3,574,101 3,184,474 3,415,750 3,576,743 3,215,707 3,433,744 3,630,904 3,219,666 3,444,170 3,632,510 3,271,310 3,448,048 3,632,511 3,272,746 3,448,049 3,697,428 3,281,357 3,451,933 3,725,441 3,306,908 3,454,607 4,194,886 3,311,558 3,467,668 4,234,435 3,316,177 3,501,405 4,491,527 3,340,281 3,522,179 5,696,060 3,341,542 3,541,012 5,696,067 3,346,493 3,541,678 5,779,742 3,351,552 3,542,680 RE 26,433 3,381,022 3,567,637 (2) Reaction products of relatively high molecular weight aliphatic or ahcyclic hahdes with amines, preferably polyalkylene polyamines. These may be characteπzed as "amme dispersants" and examples thereof are descπbed for example, in the following U.S. patents: 3,275,554 3,454,555 3,438.757 3,565,804 (3) Reaction products of alkyl phenols in which the alkyl groups contains at least about 30 carbon atoms with aldehydes (especially formaldehyde) and amines (especially polyalkylene polyamines), which may be characteπzed as "Mannich dispersants". The mateπals descπbed m the following U. S. patents are illustrative:' 3,413.347 3,725,480 3,697,574 3,726,882 3,725,277 (4) Products obtained by post-treating the carboxyhc amme or Mannich dispersants with such reagents as urea, thiourea, carbon disulfide, aldehydes, ketones, carboxyhc acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boron compounds, phosphorus compounds or the like. Exemplary materials of this kind are described in the following U.S. patents: 3,036,003 3,282,955 3,493,520 3,639,242 3,087,936 3,312,619 3,502,677 3,649,229 3,200,107 3,366,569 3,513,093 3,649,659 3,216,936 3,367,943 3,533,945 3,658,836 3,254,025 3,373,111 3,539,633 3,697,574 3,256,185 3,403,102 3,573,010 3,702,757 3,278,550 3,442,808 3,579,450 3,703,536 3,280,234 3,455,831 3,591,598 3,704,308 3,281,428 3,455,832 3,600,372 3,708,522 4,234,435 (5) Polymers and copolymers of oil-solubilizing monomers such as decyl methacrylate, vinyl decyl ether and high molecular weight olefins with monomers containing polar substituents, e.g., aminoalkyl acrylates or methacrylates, acrylamides and poly-(oxyethylene)-substituted acrylates. These may be characterized as "polymeric dispersants" and examples thereof are disclosed in the following U.S. patents: 3,329,658 3,666,730 3,449,250 3,687,849 3,519.565 3,702,300 The above -noted patents are incorporated herein by reference for their disclosures of ashless dispersants. The above-illustrated other additives may each be present in lubricating compositions at a concentration of as little as 0.001% by weight, usually ranging from about 0.01% to about 20% by weight. In most instances, they each contribute from about 0.1% to about 10% by weight, more often up to about 5% by weight. Additive Concentrates The various additive compositions of this invention described herein can be added directly to the oil of lubricating viscosity. Preferably, however, they are diluted with a substantially inert, normally liquid organic diluent such as mineral oil, a synthetic oil such as a polyalphaolefm, naphtha, benzene, toluene or xylene, to form an additive concentrate. These concentrates usually compπse about 0 1 to about 30% by weight, frequently from about 1% to about 20% by weight, more often from about 5% to about 15% by weight, of the interpolymers of this invention and may contain, in addition, one or more other additives known m the art or descπbed heremabove. Additive concentrates are prepared by mixing together the desired components, often at elevated temperatures, usually less than 150° C, often no more than about 130° C , frequently no more than about 115° C. Lubπcating Oil Compositions The interpolymers of this invention are useful as viscosity improving agents. They are used in viscosity improving amounts, typically minor amounts, that is less than 50% by weight of the lubπcating oil composition with a major amount of an oil of lubπcating viscosity, that is, the oil of lubπcatmg viscosity compπses greater than 50% by weight of the lubπcating oil composition. Preferably, they are used amounts ranging from about 0.1 to about 5% by weight, more often from about 0.3 to about 2.5% by weight of the total weight of the lubπcating oil composition. The Oil of Lubncatinε Viscosity The lubπcatmg compositions of this invention employ an oil of lubπcating viscosity, including natural or synthetic lubπcating oils and mixtures thereof. Mixture of mineral oil and synthetic oils, particularly polyalphaolefm oils and polyester oils, are often used. Natural oils include animal oils and vegetable oils (e.g. castor oil, lard oil and other vegetable acid esters) as well as mineral lubπcating oils such as liquid petroleum oils and solvent-treated or acid treated mineral lubncating oils of the paraffmic, naph theme or mixed paraffinic-naphthenic types. Hydrotreated or hydrocracked oils are included withm the scope of useful oils of lubπcating viscosity. Oils of lubπcating viscosity deπved from coal or shale are also useful. Synthetic lubncating oils include hydrocarbon oils and halosubstituted hydrocarbon oils such as polymeπzed and mterpolymeπzed olefms, etc. and mixtures thereof, alkylbenzenes, polyphenyl, (e.g., biphenyls, terphenyls, alkylated polyphenyls, etc.), alkylated diphenyl ethers and alkylated diphenyl sulfides and their deπvatives, analogs and homologues thereof and the like. Alkylene oxide polymers and interpolymers and deπvatives thereof, and those where terminal hydroxyl groups have been modified by esteπfication, ethenfication, etc., constitute other classes of known synthetic lubπcating oils that can be used. Another suitable class of synthetic lubπcating oils that can be used compπses the esters of dicarboxy c acids and those made from C 5 to C 12 monocarboxyhc acids and polyols or polyether polyols. Other synthetic lubπcating oils include liquid esters of phosphorus-containing acids, polymeπc tetrahydrofurans, alkylated diphenyloxides and the like. Unrefined, refined and rerefmed oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed heremabove can used in the compositions of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. Refined oils are similar to the unrefined oils except they have been further treated in one or more puπfication steps to improve one or more properties Reref ed oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used m service. Such rerefmed oils often are additionally processed by techniques directed to removal of spent additives and oil breakdown products Specific examples of the above-descπbed oils of lubπcating viscosity are given in Chamberlm LH, U.S. 4,326,972 and European Patent Publication 107,282, both of which are hereby incorporated herein by reference for relevant disclosures contained therein. A basic, bπef descπption of lubπcant base oils appears in an article by D V Brock, "Lubπcation Engmeenng", Volume 43, pages 184-5, March, 1987, which article is expressly incorporated by reference for relevant disclosures contained therein. The following examples illustrate lubπcating oil compositions of this invention All parts are parts by weight. Amounts are on an oil or diluent free basis, except for products of Examples set forth herein which are as prepared, including diluent, if any. Examples A-B A master additive concentrate is prepared by combining 1.34 parts calcium overbased (MR 20) alkyl benzene sulfonic acid, 0.62 parts calcium overbased (MR 2.8) alkyl benzene sulfonic acid, 1.54 parts magnesium overbased (MR 14.7) alkyl benzene sulfonic acid, 16.60 parts polyisobutylene (M n ~ 1750) substituted succinic anhydπde-ethylene polyamme bottoms reaction product, 7.61 parts of Zn mixed isopropyl-methyl amyl phosphorodithioate, 2.78 parts calcium overbased (MR 3.5) sulfurized alkyl phenol, 3.19 parts sulfuπzed butadiene-butyl acrylate Diels-Alder adduct, 0.08 parts of a kerosene solution of a commercial silicone antifoam, 1 part of sodium overbased (MR 16) polyisobutylene (M n ~ 1000) substituted succinic acid, 6.85 parts polyisobutylene ( n ~ 1000) substituted succinic anhydnde- pentaerythπtol-ethylene polyamine reaction product, 4.84 parts alkylated diphenyl am e and sufficient mineral oil to bnng the total weight of the additive concentrate to 100 parts. Engine oil compositions are prepared by combining 11 parts of the master concentrate, 0.02 parts by weight of a hydrogenated styrene butadiene copolymer and the indicated amount of the product of the indicated Example in sufficient mineral oil basestock (Petro-Canada SAE 5W-30) to prepare 100 parts by weight of oil composition. Details regarding each are provided in the following table: (pbw) - parts by weight It is known that some of the mateπals descπbed above may interact m the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions (of, e.g., a detergent) can migrate to other acidic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not susceptible of easy descπption. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components descnbed above. Each of the documents refeπed to above is incorporated herein by reference. Except in the examples, or where otherwise explicitly indicated, all numeπcal quantities in this descπption specifying amounts of mateπals, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about" Unless otherwise indicated, each chemical or composition refeπed to herein should be interpreted as being a commercial grade mateπal which may contain the isomers, by-products, deπvatives, and other such mateπals which are normally understood to be present in the commercial grade. However, the amount of each chemical component is presented exclusive of any solvent or diluent oil which may be customaπly present in the commercial mateπal, unless otherwise indicated. It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined As used herein, the expression "consisting essentially of" permits the inclusion of substances which do not mateπally affect the basic and novel characteπstics of the composition under consideration. While the invention has been explained in relation to its prefeπed embodiments, it is to be understood that various modifications thereof will become apparent to those skilled m the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications that fall with the scope of the appended claims.

Claims: What is claimed is: 1. A lubncating oil composition compπsing a major amount of an oil of lubncating viscosity and a minor, viscosity improving amount, of a substantially random mterpolymer resulting from polymeπz g (1) from about 19.5 to about 98.5 mole percent of ethylene; (2) from about 0.5 to about 60 mole percent of one or more vmyhc monomers selected from the group consisting of aromatic, hindered aliphatic, and cycloaliphatic vmyhc monomers; and (3) from about 1 to about 80 mole percent of one or more olefinic monomers having from 3 to about 20 carbon atoms. 2. The lubπcating oil composition of claim 1 wherein component (1) compπses from about 25 to about 95 mole percent of ethylene; component (2) compnses from about 1 to about 55 mole percent of one or more aromatic vinyhc monomers or hindered aliphatic or cycloaliphatic vinyhc monomers; and component (3) compnses from about 4 to about 65 mole percent of one or more olefinic monomers having from 3 to about 20 carbon atoms. 3. The lubπcating oil composition of claim 2 wherein component (1) compπses from about 30 to about 94 mole percent of ethylene; component (2) compπses from about 1 to about 50 mole percent of one or more aromatic vmyhc monomers; and component (3) compπses from about 5 to about 50 mole percent of one or more olefinic monomers having from 3 to about 20 carbon atoms. 4 The lubπcating oil composition of claim 1 wherein the mterpolymer has M w ranging from about 10,000 to about 700,000. 5. The lubncating oil composition of claim 1 wherein the mterpolymer is a terpolymer; component (2) is an aromatic vmyhc monomer; and component (3) is an alpha olefin having from 3 to about 12 carbon atoms. 6. The lubπcating oil composition of claim 1 wherein component (2) is styrene; and component (3) is one or more olefimc monomers selected from the group consisting of propylene, butene-1, 4-methyl-l-pentene, pentene-1, hexene-1 and octene-1. 7. The lubncating oil composition of claim 2 wherein the mterpolymer is a terpolymer; component (2) is an aromatic vmyhc monomer; and component (3) is an olefinic monomer having from 3 to about 12 carbon atoms. 8. The lubπcating oil composition of claim 1 wherein the mterpolymer is a terpolymer; component (2) is styrene; and component (3) is selected from the group consisting of propylene, butenes, hexene-1 and octene-1 9 The lubπcatmg oil composition of claim 7 wherein component (2) is styrene; and component (3) is an alpha oleftn having from 3 to about 8 carbon atoms. 10. The lubπcating oil composition of claim 7 wherein component (2) is styrene; and component (3) is propylene, butene-1, 4-methyl-l-pentene, pentene-1, hexene-1, octene-1 or norbornene. 11. The lubπcating oil composition of claim 10 wherein component (3) is propylene. 12. The lubπcating oil composition of claim 10 wherein component (3) is butene-1. 13. The lubncating oil composition of claim 10 wherein component (3) is hexene-1 14. The lubncating oil composition of claim 10 wherein component (3) is octene-1 15 An additive concentrate compnsmg from about 0.1% to about 30% by weight of a substantially random mterpolymer resulting from polymeπzmg (1) from about 19.5 to about 98.5 mole percent of ethylene; (2) from about 0.5 to about 60 mole percent of one or more vinylic monomers selected from the group consisting of aromatic, hindered aliphatic, and cycloaUphatic vinylic monomers; and (3) from about 1 to about 80 mole percent of one or more olefinic monomers having from 3 to about 20 carbon atoms, and from about 70% to about 99.9% by weight of a substantially inert, normally liquid, organic diluent. 16. The additive concentrate of claim 15 further comprising at least one pour point depressant. 17. The additive concentrate of claim 15 further comprising at least one organic antioxidant.

Inventors: BOWEN DANIEL E, COVITCH MICHAEL J, BOWEN, DANIEL, E., COVITCH, MICHAEL, J.
Applicants: BOWEN DANIEL E, COVITCH MICHAEL J, LUBRIZOL CORP, BOWEN, DANIEL, E., COVITCH, MICHAEL, J., THE LUBRIZOL CORPORATION
Application year: 2000
Main classification: C10M159
IPC codes: C10M101, C10M143, C10M159, C10M169, C10N20, C10N30