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Publication numberUS2892793 A
Publication typeGrant
Publication dateJun 30, 1959
Filing dateSep 19, 1957
Priority dateSep 19, 1957
Publication numberUS 2892793 A, US 2892793A, US-A-2892793, US2892793 A, US2892793A
InventorsWilliam T Stewart, Frank A Stuart, Donovan R Wilgus
Original AssigneeCalifornia Research Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Lubricant composition
US 2892793 A
Abstract  available in
Images(14)
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Claims  available in
Description  (OCR text may contain errors)

United States Patent p LUBRICANT COMPOSITION William T. Stewart, El Cerrito, Donovan R. Wilgus,

No Drawing. Application September 19, 1957 Serial No. 684,834

13 Claims. (Cl. 252-56) This invention relates to a novel lubricant composition. More particularly, the invention is directed to a novel lubricant composition which is unusually effective in the lubrication of internal combustion engines.

Improvements in the design of internal combustion engines during recent years and changes in the conditions of modern-day engine operation have emphasized the need for more effective lubricant composition. The lubricant compositions must enable the engines to operate for prolonged periods at the'highest possible efficiency under widely varying conditions. To do this, they must reduce friction, thereby increasing the efiiciency of the engines, and at the same time decrease attrition of certain rubbing parts, such as piston rings and cylinder walls.

In the operation of internal combustion engines, substantial amounts of solid deposits tend to occur on the interior surfaces. These deposits have a serious effect on the operating efiiciency of the engines, since they add greatly to the friction of rubbing surfaces and interfere with proper circulation of the lubricants. For the same reason, the wear of the rubbing surfaces is greatly accelerated, resulting eventually in a serious loss of power, and more frequent replacement or overhaul of the piston rings and cylinder walls becomes necessary. Lubricant compositions which prevent or minimize the formation of solid deposits within the internal combustion engines are therefore highly desirable.

The operation of internal combustion engines is also affected by the corrosive attack on metal surfaces of moisture and acids formed in the combustion of the fuels. This leads to additional wear of piston rings and cylinder walls, as well as other metal surfaces. The ability of lubricant compositions to decrease wear due to corrosion in internal combustion engines is thus an important attribute.

The formation of solid deposits within internal combustion engines and the wear of rubbing surfaces is considerably aggravated by the conditions under which such engines are commonly used in this day. In the stopping and starting of automobile engines during city driving, for example, the engines are repeatedly started in cold condition and operated for short periods of time, insufi"1 cient for them to reach the more etficient higher temperatures. Increased amounts of partial oxidation products of the fuels, and also of the lubricant compositions to a somewhat less degree, are thus formed and never fully exhausted from the engine. These products are generally either insoluble or sparingly soluble in lubricating oils. Even the slightly soluble ones tend to polymerize or conglomerate, with the formation of insoluble masses which deposit out on contact with engines surfaces. Other oxidation products of the fuel and lubricant composition 2,892,793 Patented June 30, 1959 are acidic by nature and combine with moisture under the relatively cold operation conditions of city driving to cause further undesirable Wear of the piston rings and cylinder walls.

Lubricant compositions have been prepared with additives to inhibit the formation of solid deposits and reduce the wear of rubbing parts. Detergents have been added to prevent or minimize engine deposits. These detergents are generally metal-containing compounds such as calcium petroleum sulfonate, calcium cetyl phosphate, calcium phenyl stearate and the like. Metal salts of petroleum sulfonic acids and other metallo-organic compounds, particularly those having a basic reaction, have also been added to counteract the effect of moisture and acidic products on metal surfaces within the engines.

Lubricant compositions with additives of the above type have not been completely satisfactory in the lubrication of modern internal combustion engines under present-day operating conditions. Their ability to solubilize oxidation products and avoid the formation of solid deposits has been somewhat limited at the lower temperatures and the corrosion of metal surfaces has not been satisfactorily inhibited. A further disadvantage of the metal-containing additives employed heretofore has been that they may form an ash upon combustion which deposits out upon surfaces within the internal combustion engine, thereby resulting in a decrease of engine efficiency and an increase in wear of engine parts, as described above.

In the present invention, a new and unusually effective lubricant composition has been discovered comprising a major portion of an oil of lubricating viscosity and a' minor portion, suflicient to enhance the detergent characteristics of the composition, of an oil-soluble mixture of (A) the copolymer of at least one monomer selected from the group consisting of (l) a fatty acid ester of an unsaturated alcohol, said fatty acid containing up to 30 carbon atoms and said unsaturated alcohol being selected from the group consisting of a. and B-unsaturated alcohols containing up to 20 carbon atoms, (2) l-olefins of 2 to 30 carbon atoms, and (3) vinyl and allylalkyl ethers having 1 to 30 carbon atoms in the alkyl group with a monomer of the group consisting of maleic anhydride and alkyl, cycloalkyl, aryl, alkaryl and aralkyl ot,ot'-Sl1b stituted maleic anhydrides containing up to 20 carbon atoms, said monomers being in approximately 1:1 molar ratio, and (B) a copolymer comprising as its monomers a member of the group consisting of maleic anhydride and alkyl, cycloalkyl, aryl, alkaryl and aralkyl a d-substituted maleic anhydrides containing up to 20 carbon atoms and at least one olefinically unsaturated oil solubilizing monomer having an aliphatic hydrocarbon group of 4 to 30 carbon atoms, at least one of said (A) and (B) copolymers being partially esterified with a member of thegroup consisting of polyalkylene glycols and ethers thereof in which the alkylene groups contain from 2 to 7 carbon atoms each and the alkyl groups contain from 1 to 30 carbon atoms each and said'(A) and (B) copolymers being in the weight ratio of 0.15 to 5 parts of (A) for each part of (B), and a portion of the maleic anhydride and substituted maleic anhydride in the copolymers one hydrogen of their alkyl group, but not more than onehalf thereof, substituted by a polar group. Copolymers containing thea'mid'e's, amine salts and esters are'a' distinct species from those having the free carboxylic acid group and copolymeric mixtures containing them possess highly useful detergent characteristics in lubricant compositions which could not be predicted from the unmixed copolymers alone.

Novel lubricant compositions of the type according to the present invention as described above are outstanding in the lubrication of internal combustion engines, even under the more stringent operating conditions commonly encountered in' the engines of today. Remarkably little or no deposits are formed on the interior surfaces of internal combustion engines employing these compositions thus providing more efficient operation while at the same time decreasing undesirable wear of rubbing surfaces within the engine. Wear of engine parts due to corrosive attack is also effectively inhibited by the use of the compositions of the invention. Such benefits are all the more noteworthy, since they are apparently attained without any loss of additive or other detrimental effect on the lubricant composition. This is wholly unlike previous experiences with conventional compositions for such purposes where the additive is used up due to its combination with the objectionable deposit-forming and wear-inducing partial oxidation by-products of lubricating oil bases and fuels, A still further important advantage of the lubricant compositions lies in the fact that the detergent and wear-inhibiting additive does not contain metal which could itself contribute to the formation of deposits upon combustion.

The fatty acid ester of an unsaturated alcohol in component (A) of the mixture of copolymers, as already mentioned, may contain up to 30 carbon atoms in both the fatty acid and the unsaturated alcohol, and the unsaturated alcohol may be either an a or p-unsaturated alcohol. Illustrative fatty acid esters of this typeare:

Vinyl fox-mate Vinyl palmitate Vinyl caprylate Vinyl eicosenoate Allyl acetate- Allyl laurate Allyl steal-ate Allyl 2-ethylhexanoate Methallyl caproate Methallyl palmitate Crotyl acetate Crotyl stearate l-propenyl isobutyrate l-hexenyl acetate 2-decenyl caproate 2-decenyl laurate l-hexadecenyl myristate 2-eic0senyl palmitate the most effective detergents and wear inhibitors when incorporated in the copolymers of the -lubricant compositions in accordance with this invention,

In the present description, the terms higher fatty acids" and higher alkylesters are ernployed intheir commonly accepted sense and refer to fatty acids containingjat least 8 carbon atoms and allgyl estersin which the alkyl group contains at least 8 carbon atoms. Ordinarily, not more than 30 carbonatoms are necessary such groups for the purposes of this invention.

For presentpurposes the fatty acid esters of unsaturatedalcohols are preferred in the '(A) component for their effectiveness in the oil-soluble mixtures of copolymers according to the invention.

A distinct species of the/invention within the terms,

of the general statement above may also be obtained-by including in copolymer (B) a fatty acid ester of an unsaturated alcohol "of the type described in connection with copolymer (A). Copolymers of this specific type have been found to produce lubricant compositions have ing superior detergency under certain conditions compared to compositions in which the fatty acid ester ,ofnn-p saturated alcohol was omitted from the '(B) copolymer.

On the other hand, lubricant compositions containing copolymeric mixtures wherein the (B) component is the copolymer of the maleic anhydride compound and the olefinically unsaturated oil solubilizing monomer alone without the unsaturated alcohol ester constitute a very effective species of the invention having excellent detergent properties which would not be expected from the performance of the unmixed -copolymers.

Described in another way, the (B) component of the copolymer mixtures employed in the lubricant compositions of the invention may include other monomers of the type described herein, along with the maleic anhydride or substituted'maleic anhydride and oil solubilizing monomer. The two species of invention mentioned in'the preceding paragraph are particular types of lubricant compositions containing mixed copolymers in which the (B) component is a copolymer of monomers selected from at least the first two classes of the group consisting of (l) maleic anhydride and alliyl, cycloalkyl, aryl, alkaryl and aralkyl a,a"-snbstitutedmaleic anhydrides containing up to 20 carbon atoms, (2) an olefinically unsaturated oil solubilizing monomer having an aliphatic hydrocarbon group of 4 to 30 carbon atoms and (3) a fatty'acid ester of an unsaturated alcohol 'in which the fatty acidv contains up to 30. carbon atoms and the unsaturated'alcohol' is a member of the group consisting of a and B-unsaturated alcohols containing up to 20 carbon atoms.

The l-olefins of 2 to 30carbon atoms are well known andireadily available from a number of sources including the polymerization of .olefins such as ethylene and propylene, cracking of hydrocarbons, dehydrogenation of hydrocarbons, dehydration of alcohols and the like. They are essentially aliphatic in structure and contain a single olefinic double bond in the 1-position. Preferred l-olefins are thosecontaining '6 to' 24 carbon atoms. The following are illustrative:

Ethylene Hexene-l 2-ethylhexene-1 Oetadecene-l Diisobutylene Eicosenene-l Trusobutylene 4-octylcyclohexene-1 Propylene trimer 3-phenylhexadecene-1 Dodecene-l p-Octylstyrene Eexadecene-l Vinyleyclohexane The vinyl and allyl alkyl ethers, as already mentioned, have l to 30 carbon atoms in the alkyl group. Pre ferred are those containing 4 to 22 carbon atoms in the alltyl poftionfthereof. Illustrative ethers include:

The maleic anhydride and u,ot'-Sllb$titllt6d maleic anhydrides containing up to 20 carbon atoms in component (A) of the copolymer may be illustrated by the follo'wing'stru'ctu'ral formula:

inwhichR andR are the same or different members ofthei group consisting of hydrogen and alkyl, cycloalkyl, aryl, alkaryl and aralkyl groups together containing not more than 16 carbon atoms. Illustrative'anhydrides of this type are maleic anhydride, citraconic anhydride, otherwise described as a-methyl maleic anhydride, ozhexyl maleic anhydride, u,oc'-diOCty1 maleic anhydride, a-methyl od-cyclohexyl maleic anhydride, a,a-dipheny1 maleic anhydride, u-methyl a-benzyl maleic anhydride, u-tertiary butylphenyl maleic anhydride, a,a'-dixylyl anhydride and ot-cetyl maleic anhydride. Maleic anhydride is presently preferred, since it is most readily available and provides block copolymers of the greatest effectiveness in the lubricant compositions according to this invention.

In component (B) of the copolymers, the maleic anhydride and t d-substituted maleic anhydrides containing up to 20 carbon atoms may be the same as in the (A) component described in the preceding paragraph, or they may be different, so long as they fall within the terms of the general description set out above.

The olefinically unsaturated oil solubilizing compound containing an aliphatic hydrocarbon group of from 4 to 30 carbon atoms may be selected from a wide variety of well-known oil solubilizing monomers which have been employed heretofore in the production of polymers for addition to lubricant compositions to modify their physical properties, that .is, their viscosity indexes and pour point characteristics. The aliphatic hydrocarbon group and the polymerizable olefinic double bond are the two essential features of these oil solubilizing compounds. The aliphatic group is branched or straight chain alkyl or cycloalkyl in structure. This is illustrated by radicals such as butyl, isobutyl, 2-ethylhexyl, cyclohexyl, tetradecyl, stearyl, eicosenyl, oleyl and ricinoleyl. The aliphatic hydrocarbon groups are linked to the polymerizable olefim'c double bonds or vinylene groups either directly or by an oxygen-containing group, as in the case of ethers, esters, ketones.

The olefinically unsaturated oil solubilizing monomers of component (B) may also be illustrated by the following general formula:

in which R and R are members of the group consisting of hydrogen and hydrocarbyl radicals of from 4 to 30 carbon atoms, at least one of which contains an aliphatic hydrocarbon group of from 4 to 30 carbon atoms as described above, G and G are members of the class consisting of oxy (-0), carbonyl groups and combinations thereof with not more than two alkylene groups of from 1 to 7 carbon atoms each and n and n are 0 or 1. When R and R are hydrocarbyl radicals, they may be alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl or aralkyl in structure as illustrated by radicals such as 2-ethylhexyl, cyclohexyl, hexenyl, cyclohexenyl, phenyl, naphthyl, tertiary butylphenyl, benzenyl, etc.

The olefinically unsaturated oil solubilizing compound referred to above may also be an a or fi-unsaturated alcohol'ester of a fatty acid, either like or unlike the ester monomer already described in connection with copolymer (A) and copolymer (B). Mixtures of the oil solubilizing monomers may be employed if desired.

The following olefins,-ethers and esters are offered as illustrations of suitable oil-soluble monomers for preparaand carbonyloxy tion of the (B) Copolymers employed in the lubricant com-- positions of the invention:

l-decenyl 2-phenylbutyl ether ESTERS Oyclohexyl methacrylate Deeyl vinylacetate P-isoamylphenyl 2-hexadecenoate Undecyl einnamate 5-ethyldocosyl crotonate N-butyl 2-eieosenoate p-Hexadecylphenyl 2ethylhexyl maleate Dihexadeeyl maleate Mono-2-ethylhexyl maleate Di-dodecyl maleate Di-d0decy1 eitraconate Mono-hexadecyl itaconate l-decenyl laurate Dodecyl acrylate Isobutyl a-decylacrylate Dlingnylphenoxyethyl methacry- ,Cyclohexyl Z-dodecenoate Isooctyl a-chloroacrylate 4-p-tolylbutyl 2-oetadecenoate Methylcyclohexyl 2-ethyl-2-hexenoate Octadecyl isocrotonate p-Tgit. amylphenyl octadecyl m eate o-Tolyl 2-oetadecylcyclohexy1 maleate o-Nonylphenyl-hexadeeyl rnaleate Di-methylcyclohexyl maleate Di-Z-ethylhexyl fumarate Di-dodeeyl Inesaconate o-Tolyl octadecyl itaeonste Isopropeuyl palmitoleate l-hexadecenyl myristate Hexadecyl methaerylate Oetylphenoxye yl methaerylate Vinyl n-buty] ketone Vinyl 2-ethylhexyl ketone Methallyl octadecyl ketone l-decenyl butyl ketone Allyl cyclohexyl ketone l-eicosenyl decyl ketone Alliyl 4,4,8,8-tetramethy1docosyl Vinyl p-octylphenyl ketone e one Although any of the olefinically unsaturated oil solubilizing compounds described above will give effective copolyrner compositions for lubricant compositions in accordance with the present invention, higher alkyl esters of c p-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms are preferred. Representative acids of this type are the acrylic, methacry-lic, crotonic, tiglic, angelic, wethylacrylic, u-methylcrotonic, u-ethylcrotonic, p-ethylcrotonic, a-butylcrotonic, hydrosorbic, oc-ethylhydrosorbio and u-propylhydrosorbic acids and the like. Even more desirable are the alkyl esters of acrylic and methacrylic acids containing from 10 to 20 carbon atoms in the alkyl groups, since they are found to provide highly superior polymers for the lubricant compositions of the invention and are obtainable in commercial quantities.

The polyalkylene glycols and alkyl ethers thereof used in the esterification of the copolymeric (A) and (B) components of the copolymer additives for the lubricant compositions of the invention contain from 2 to 7 carbon atoms in each alkylene group and 1 to 30 carbon atoms in each alkyl group, as already mentioned. Poly-1,2- alkylene glycols and their alkyl ethers having molecular weights between 106 and 10,000 are preferred. Such glycols may be obtained by polymerizing 1,2-alkylene oxides or mixtures thereof in the presence of a catalyst and a suitable initiator for the reaction such as water, monohydric alcohol, in the case of the alkyl ethers, mercaptan and the like. The preparation of polyglycol compounds of this type hasbeen fully described heretofore in U.S. Patents 2,448,664, 2,457,139, for example, and therefore, requires no detailed discussion here.

For present purposes, the most suitable poly-1,2-alkylene glycols are those derived from ethylene oxide or from ll-propylene oxide or mixtures thereof and their alkyl ethers of 1 to 18 carbon atoms per alkyl group which have molecular weights or average molecular weights between about 200 and 2000. Copolymers partially esterified with these polyalkylene glycols are found to pro-.

T videthe -mosteifective detergent} and Z. wear inhibiting compositions. r 1

The following polyalkylene. glycols containing from 2 to 7 carbon atoms each are illustrative of the typesadescribed above.

Polyethylene glycol mixtures having average molecular weights of 200, 4001000, 1540 or 2000.

Poly-1,2-propylene glycol mixtures having average molecular weights of 425 or 1025.

The'copolymers of the lubricant compositions of the invention, as mentioned in the general statement given above, have a portion of the maleic anhydride and substituted maleic anhydride monomer present as a derivative thereof selected from the group consisting of a free carboxylic acid, an amide, N-alkyl amides and amine salts, alkyl esters and n-alkyl amides and amine .salts and alkyl esters having at leastone hydrogen of their alkyl group but not more than one-half thereof substituted by a polar group. Such maleic anhydride and substituted maleic anhydridetype compounds in thetcopolyrnersmay be represented'b y thefollowing formula:-

in'whichlM andM represent the-balance of the copoly-- mer, theRs arehydrogen d hydrocarbyl radicals of the type already discussed k andrR which may be the same ordifie'rent, are groups .selectedafrom the class consisting of.polyoxyalkyleneoxy groups obtained .when-polyalkylene glycolslof the above-described types are: reacted with maleicsan hydride, an hydroxyl group, an .amidegroup, N-alkyl amide andaminesaltl groups, alkoxy groups and N-alkyl amideand amine salt groups and alk'oxy groups having atrleast onehydrogen of their alkyl group, but not more than one-half thereof; substituted by a polar group. I

In the case of the N-alkyl amide and amine'salt groups, asrwell as .theN-alkyl amide and amine'salt groups having alkyl group hydrogens substituted by polar groups,

Amine salt in which formulae the *R gs are hydrogen atoms or alkyl" and polar substitut ed alkyl groups, .and ithe-Ris sare alkyl? or polar. :substitutedfal'kyl groups similar .torthe R groups; Preferred alkyl groups are the-lower alkyl :groups; that: is;thosecontaining fromzl to :7 carboni'atorns; Thelpolarr groups mayr be: any. of-s the: class ofi'groups which are: known tot-impartp'olarity'to:adorganic molecule; Illusw trative-s groups: of .thisc-type: are the amino,- bromo,- car--- boxyj'ch'loro; tcyano, timido, rimino, isocyano, .mercapto; nitramino; nitro, nitroso; sulfo; and thiocyano groups Preferred? polar: groups .1 are" the amido, amino, hydroxy and: m'ercapto groups;

In the case of the alkoxy and polar substituted alkoxy: groups, the alkyl groups: and polar substituted alkyl group'smaybeas described above in connection with the aminersalt andJamide groups;

'lllustrative'zN polar substituted alkyl amide and amine salt groups 'ioftheapreceding types are as follows:

Eth-anolaminesalt Diethanolamine: sa lt' Mercaptoethylamine salt I Diethylenetriamine salt Tetraethylenepentaminesalt Dihydroxyet-hyl ethylenediamine salt Triethanol'amine salt 2,5-dirnethylpiperazine salt -3-hyclroxymorpholine sa lt N-' Z-hydroxyethyl -amide- N-(LZ-mercaptoethyl) -arnide N-(Z-aminoethyl) -amide N'- 4-aminobutyl) -amide N-(-4 aminohexyl) -arnide' N 3-azapentyl) -amide N'-i( Z- nitrohexyl) -amide N- 2,3-dihydroxypropyl) amide' N- Z-hydroxy-S -mercaptopentyl) amide N- (4-hydroxycyclohexyl -amide N- 2-ethyl-6-aminohexyl) -*amide 3-nitromo1'pho1ine amide N-ethyl-N- (2-hydroxyethyl) -amide N,N-di Z-hydroxyethyl) -amide N- Z-hydroxyethyl) -N-aminomethyl-amide N-(Z-nitroethyD-amide N- 2-hydroxy-6-phenylhexyl) arnide N-(Z-hydroxyethyD-N-(B -aza-5-hydroxypentyl)-arnide The amide of 2-hydroxyethyl p-arninobenzoate The amide of pentaeryth'ritol mono-p-arninobenzoate The amide of Z-hydroxyethyl 3-amin0propionate' Alcohols which provide substituted alkyl ester groups, or the alkyl portion of the polar substituted alkoxy groups as they are termed above, include:

3,5-dinitrocyclohexyl alcohol It will be noted from the above examples that the polar substituted alkyl groups are straight chain alkyl, branched alkyl or cycloalkyl in structure and contain at least one.

polar group. In the case of the polar substituted alkyl. ester groups, or' alkoxygroups as' they havealso beentermed, it'is'desirable that "at least half, and not-less than -2, of'the-carbon atoms'in'the alkyl portion beattached i escapes g to the polar gio'ups. As already mentioned, preferred alkyl groups are the lower alkyl groups of from 1 to 7 carbon atoms. Although the amido, amino, hydroxyl and mercapto groups constitute a preferred class of polar groups, the greatest preference is given to the amino and hydroxyl groups, particularly the latter.

In the preparation of the copolymer additives for lubricant compositions according to this invention the ratio of the various monomeric and polymeric components to one another is such that the final mixture of copolymers is soluble in the mineral oil or other oil of lubricating viscosity in amounts sufficient toenhance the detergent characteristics and wear inhibiting properties of the composition; Generally, the ratios are such that the lubricant compositions contain at least 0.1% by weight and preferably 1% or more of the copolymer mixture on the basis of the entire lubricant composition. Inasmuch as the various monomeric components described hereinbefore possess differing oil solubilizing effects, it is convenient to test the oil solubility of the copolymers until the proper ratios are determined.

It has been found that copolymers having the desired degree of oil solubility as described above and possessing detergent enhancing and wear inhibiting properties generally contain monomeric ratios which fall within certain numerical ranges. In the copolymeric (B) component of the mixture containing an unsaturated alcohol ester as previously described, from about 0.25 to 4 moles of the on or p-unsaturated alcohol ester of a fatty acid is present for each mole of the maleic anhydride compounds. The olefinically unsaturated oil solubilizing monomer in the copolymeric (B) component is ordinarily present in molar proportions 5 to 50 times that of the combined amount of a or fl-uns'aturated alcohol fatty acid ester and maleic anhydride compound. Stated otherwise, this usually amounts to from about 83 to 98 mole percent of the (B) component. Ordinarily from about 0.15 to about 5 parts by weight of copolymeric component (A) are present for each part by weight of the copolymeric (B) component in the mixture of copolymers. Preferably, the weight ratio of (A) to (B) is in the range of from 0.25 to 2 of (A) for each part of (B). The polyalkylene glycol esterifying the copolymeric (A) and (B) components is such that a total of from about 2 to 75% of the maleic acid anhydride of the (A) and (B) components is esterified. This means that usually from about 0.04 to 1.5 mole of polyalkylene glycol is present for each mole of maleic anhydride or that from about 1 to 25 Weight percent of the final polymer mixture is polyalkylene glycol present as an ester group. As will be apparent from the last-mentioned properties, the copolymers of the compositions according to the invention are characterized by the presence of free acid or carboxyl groups which are in turn suit-ably converted to amide, amine salt or ester derivatives thereof, since only onehalf of a maleic acid anhydride group is often esterified.

As already mentioned, the maleic anhydride compound and the other monomer of the (A) component are present in approximately 1:1 molar ratio. Minor variations of, for example, one-half a mole either way are permissible to provide a molar ratio of the two monomers in the range of from 0.5:1.5 to :05.

The copolymer additives of the lubricant compositions of the invention have apparent molecular weights as determined by standard light scattering methods of at least 2,000 and preferably at least about 8,000. For practical purposes, molecular weights of from 100,000 to 1 million are most suitable from the standpoint of viscosity and other physical characteristics of the polymeric additives. I

Several methods of preparing the cop-olymers for the lubricant compositions of the invention may be employed. Monomers containing reaction groups may be first poly- 10 merized and then the desired hydrocarbyl substituerits added by reaction with the group. This is'illustrated in situations where acrylic acid or methacrylic acid monomers are poly-merized and the polymeric product then esterified with a higher alkyl alcohol.

In the preparation of the copolymeric components or polymeric intermediates therefor, conventional bulk, solution or emulsion methods may be employed. Polymerization initiators such as benzoyl'peroxide, acetyl peroxide, tertiary butyl hydroperoxide or an azo initiator such as a,a'1-azodiisobuteronitrile are usually employed in amounts of 0.1 to 10%. Inert solvents may be used as needed to facilitate handling of the materials and to maintain the reaction mixture in a homogeneous condition. The copolymerization reactions are ordinarily car-' ried out at temperatures of about to 300 F., depending on'the nature of the solvent, the concentration of the reactants, the catalyst and reaction times. 7

After the copolymeric (A) and (B) components have been prepared, they may be esterified separately with the desired polyalkylene glycol or its monoether or the two copolymers may be mixed and esterified together with the polyalkylene glycol or other reactant which reacts with a portion of the maleic anhydride groups in both copolymers. This esterification is preferably carried out in the presence of catalysts such as p-toluene sulfonic acid monohydrate. Solvents such as toluene, xylene and the like are used to facilitate the reaction, and the temperatures vary from about 200 to 400 F. in accordance with known esterification procedures.

Any of the well-known types of oils of lubricating viscosity are suitable base oils for the compositions of the invention. They include hydrocarbon or mineral lubricating oils of naphthenic, parafiinic, and mixed naphthenic and parafiinic types. They may be refined by any of the conventional methods such as solvent refining and acid refining. Synthetic hydrocarbon oils of the alkylene polymer type or those derived from coal and shale may also be employed. Alkylene oxide polymers and their derivatives such as the propylene oxide polymers and their ethyl esters and acetyl derivatives in which the terminal hydroxyl groups have been modified are also suitable. Synthetic oils of the dicarboxylic acid ester type including dibutyl adipate, di-Z-ethylhexyl sebacate, di-n-hexyl fumaric polymer, dilauryl azelate, and the like may be used. Alkyl benzene types of synthetic oils such as tetra-- decyl benzene, etc., are also included. Liquid esters of acids of phosphorus including tricresyl phosphate, diethyl esters of decane phosphonic acid, and the like may also be employed. Also suitable are the polysiloxane oils of the type of polyalkyl-, polyaryl-, polyalkoxyand polyaryloxy siloxanes such as polymethyl siloxane, polymethylphenyl siloxane, and polymethoxyphenoxy siloxane and silicate ester oils such as tetraalkyland tetraaryl silicates of the tetra-Z-ethylhexyl silicate and tetra-p-tert.-butylphenyl silicate types.

As further illustrations of the invention according to the above description, the following examples are offered showing the preparation of the novel copolymeric detergents and Wear inhibitors and lubricant compositions containing them. Unless otherwise specified, the proportions are given on a weight basis.

Example I To a glass reaction flask equipped with stirring means, thermometer, reflux condenser and dropping funnel were charged 98 grams (1 mole) of maleic anhydride and 324 grams (1 mole) of allyl stearate along with about 10,

F. by heating or cooling as necessary during theaddi tion. 4.2 grams of tertiary butyl hydroperoxide was then added, following which the mixture was thoroughly stirred and allowed to stand for 18 hours at 218 F. The-mixture thus obtained was distilled to a temperature of 370 F. under a vacuum equal to about 1 mm. of mercury pressure. The product was a glassy appearing copolymer containing equimolar proportions of maleic anhydride ,andvallyl stearate and having an apparent molecular weight of about 90,000 as determined by standard light scattering methods.

2 54 grarns (1 mole) of lauryl methacrylate and 5 grams (0.05 mole) of maleic anhydride were added to a glassreaction flask equipped with mechanical stirrer, reflux condenser and thermometer. The mixture was heated toabout, 200 F. for a period of about 2 hours, during which time 2 grams of tertiary butyl peroxide was added. The temperature was maintained at 2l5-225 F. during the addition by either heating or cooling as required. When the addition of the catalyst was completed, the mixturewas allowed to stand for about 18 hours at 215-225" F. The reaction mixture was then stripped by distillation at 380 F. at 1 mm. mercury pressure. to give; a viscous oil soluble polymer shown by analysis to have amolal, ratio of lauryl methacrylate to maleic anhydride of approximately 20/ 1.

120 grams of the lauryl methacrylate-maleic anhydride (20/ 1) copolymer and 80 grams of the allyl stearatemaleic anhydride (1/1) copolymer were mixed with 16.8 grams. of polyethylene glycol monomethyl ether having an average molecular weight of about 550,- 0.34 gram of p-toluene sulfonic acid monohydrate catalyst and sufficient xylene to permit refluxing slowly at 300 F. inaglass reaction flask of the above type. The mixture was, refluxed for about nine hours while stirring. Another 33.6 grams of the polypropylene glycol'monomethyl etherand, 0.6 gram of p-toluene' sulfonic acid catalyst were: then added. Xylene was permitted to distill 011 until the temperature reached 350 F. at which temperature thereaction was maintained for about five hours. The mix-' ture was stripped to a temperature of 370 F. at a pressure of 1 mm. of mercury. An amber colored, viscous material soluble in, oil was thus obtained which consisted of the mixture of (A) allyl stearate-maleic anhydride (1/ 1) copolymer and (B) lauryl methacrylate maleic anhydride (20/1) copolymer partially esterified with. polyethylene glycol monomethyl ether having a molecular weight of about 550.

Example II An allyl stearate-maleic anhydride (1/1) copolymer having an apparent molecular weight of about 90,000 was prepared as described above. To a glass reaction flask equipped with stirrer, and reflux thermometer were charged 380 gramsof lauryl methacrylate (1.5 mole) and 5 gramsof maleic anhydride (0.05 mole). The mixture was heated to about 200 F. and 2 grams of tertiary butylv peroxide and 2 grams of benzoyl peroxide were added over a period of about 2 hours. The mixture was heated or cooled as necessary during the addition to maintain the temperature at 215-225 F. Following the addition, the mixture was heated for about l8-hours at 215-225 F. It was then stripped to a temperature of 380"F. at 1 mm. mercury pressure to yield a lauryl methacrylatemaleic anhydride (30/ 1') copolymer in the form of an amber colored, 'viscous material" having an apparent molecular; weightof' about 500,000.

1-20 of the laurylmethacrylate-maleic anhydride copolymer and 8.0.gramsofthe allyl stearate-maleic. anhydride. copolymer obtained in the abovepreparations WQ Q mixed in aglassreafitiOHWSsel with 15.0. grams of Po yethy ene glyc h u a l-a a e molecular ht; ojabout300'g 0.3 gram of p;-toluene sulf onic acid'catalyst andienou gh xylene ,to permitpslowrefluxing at about300'-" F. stirring; the mixturewas refluxed? forabout- 9 h0urs"at --300- F. Then-an additional 25.0 gramsof polyethylene glycol and 0.68 gram of the p-toluene sulfonic acid catalyst were added. The xylene was stripped. ofl? until the temperature reached 350 F. at which pointv it was held for about 5 hours. The remaining solvent was then removed by distillation up to 370 F. at 1 mm. mercury pressure. The product was a mixture of (A) allyl-stearate-maleic anhydride (1/1) copolymer and (B) lauryl methacrylate-maleic anhydride (30/1) copolymer partially esterifled with polyethylene glycol having an average molecular weight of about 400. It was a highly viscous, amber colored material which was soluble in oil.

Example III The 1/1 copolymer of allyl stearate and maleic anhydride was prepared by the procedure of the above examples.

Into a glass reaction flask was placed a mixture of 127 grams of lauryl methacrylate (0.5 mole) and 5 grams of maleic anhydride (0.05 mole). The ingredients were mixed and heated to about 220 F. 2 grams of tertiary butyl hydroperoxide and 2 grams of benzoyl peroxide were then added slowly over a period of about 2 hours. The reaction flask was heated or cooled as necessary to maintain the temperature at 215-225 F. during this period. After the mixture had been heated for an additional 18 hours at about 220 F., it was stripped to 380 F. at 1 mm. mercury pressure. The lauryl methacrylate-maleic anhydride (10/ 1) copolymer thus obtained was a viscous, amber colored oil soluble material.

grams of the allyl stearate-maleic anhydride copolymer and 120 grams of the maleic anhydride-lauryl methacrylate copolymer prepared above were mixed in the glass reaction flask and reacted with 16.8 grams of polyethylene glycol monomethylether having an average molecular weight of about 550. The catalyst was 0.34 gramof p-toluene sulfonic acid and the reaction conditions and purification steps were the same as outlined in the above examples. The final product was a copolymeric mixture of (A) maleic anhydride-allyl stearate 1/ 1 copolymer and (B) maleic anhydride-lauryl methacrylate 1/ 10 copolymer partially esterified with the polyethylene glycol monomethylether. It was viscous and amber colored in appearance and was soluble in oil.

Example IV 324 grams (1 mole) of allyl stearate, 98 grams (1 mole) of maleic anhydride and 10 cc. of benzene were charged to a three-necked flask fitted with a stirrer,

thermometer, reflux condenser and dropping funnel. The. mixture was heated to 220-225 F. with stirring. A solu-- tion of 6.3 grams of benzoyl peroxide in 100 cc. of henzene was then added over a period of 3 to 4 hours during which time the temperature was maintained between 200 and 230 F. by heating or cooling as required. After about 15 to 20 cc. of the catalyst and benzene solution had been added, polymerization began and toluene was added slowly as required to facilitate stirring of the mix-- ture. Following the addition of all of the benzoyl peroxide and benzene solution, 4.2 grams of tertiary butyl hydroperoxide was added. The mixture was thoroughly" stirred and then let stand for about 18 hours at 218 F.. The product obtained above was stripped to 370 F. at:

hydride copolymeric mixture was added 317 grams of lauryl methacrylate. The combined materials were thenheated, with stirring to 260270 F. tmtil homogeneous The solution was then cooled to 220-225 F. and a mixture of 0.7 gram of benzoyl peroxide and 0.7 gram at tertiary butyl hydroperoxide was added over a period of 13 l to 2 hours while maintaining the temperature between 220-230 F. After about 3 hours reaction time, 1.4 grams more of each of the above catalysts was added. The mixture was stirred and then allowed to stand for about 18 hours at 218 F.

The mixture obtained above was stripped to 370 F. at 1 mm. pressure to remove unreacted lauryl methacrylate. The resulting product was a viscous oil-soluble mixture shown by analyses to comprise (A) allyl stearatemaleic anhydride l/l copolymer and (B) allyl stearatemaleic anhydride-lauryl methacrylate copolymer with a molal ratio of l/ 1/ 15.

To 200 grams of the mixture of copolymers obtained above were added 16.8 grams of polyethylene glycol monomethyl ether having an approximate molecular weight of about 550, 0.34 gram of p-toluene sulfonic acid monohydrate catalyst and suflicient xylene to give slow refluxing at 300 F. This mixture was refluxed at 300 F. with stirring for about 9 hours. At this point, an additional 39.0 grams of the polyethylene glycol monomethyl ether and 0.68 gram of p-toluene sulfonic acid monohydrate catalyst were then added. Xylene was withdrawn until the temperature rose to 350 F. The reaction mixture was held at this temperature for about hours, folfolling which the xylene was stripped ofi by distillation up to 370 F. under a vacuum equal to 1 mm. mercury pressure t The mixture of copolymers of (A) allyl stearatemaleic anhydride 1/1 copolymer and (B) allyl stearatemaleic anhydride-lauryl methacrylate 1/1/15 copolymer each esterified with polyethylene glycol monomethyl ether having an average molecular weight of 550 as obtained in the above experiment was a viscous, oil-soluble, amber colored material. It contains about free unreacted polyethylene glycol monomethyl ether and may be used as is in oils of lubricating viscosity to impart enhanced detergency and wear-inhibiting properties, or it may be further purified by dissolving in 4 volumes of benzene and precipitating the polymers with 20 to 25 volumes of methanol.

Example V In this example a maleic anhydride-allyl stearate copolymer was prepared by the method described in Example IV above. It had an apparent molecular weight of about 90,000 as determined by standard light scattering methods.

A maleic anhydride-lauryl methacrylate-allyl stearate copolymer was synthesized by mixing 254 grams (1 mole) of lauryl methacrylate, 5 grams (0.05 mole) of maleic anhydride and 16.2 grams (0.05 mole) of allyl stearate in a three-necked reaction flask fitted with a stirrer, condenser and thermometer in accordance with the procedure of Example IV. The mixture was heated to 220 F. and 2 grams of benzoyl peroxide was added over a period of 2 hours. During this time, the temperature was maintained at 215-225 F. by either heating or cooling as required. Following the addition of the catalyst, the mixture was held at 215-225 F. for about 18 hours and then stripped to 380 F. at 1 mm. mercury pressure to yield 260 grams of a viscous, oil-soluble polymer shown by analysis to contain lauryl methacrylate, allyl stearate and maleic anhydride in a molal ratio of approximately 20/ 1/ 1.

A mixture of 80 grams of the allyl stearate-maleic anhydride copolymer and 120 grams of the lauryl methacrylate-allyl stearate-maleic anhydride copolymer prepared above was combined with 16.8 grams of a polyethylene glycol monomethyl ether having an average molecular Weight of approximately 550, 0.34 gram of p-toluene sulfonic acid monohydrate catalyst and suflicient xylene to permit refluxing slowly at 300 F. in the reaction flask described previously. The contents of the flask were refluxed for about 9 hours at 300 F. while stirring. At this point, 39.0 grams of the polyethylene glycol monoethyl ether were added along with 0.68 gram of catalyst. Xylene was boiled off until the temperature reached 350 F. and the reaction mixture then maintained under these conditions for about 5 hours. Following this, xylene was stripped off by distillation at 370 F. under a vacuum equal to a pressure of about 1 mm. of mercury. The product thus obtained was an amber colored viscous material which was soluble in oil.

Example VI A copolymer of allyl stearate and maleic anhydride containing equimolar proportions of the components was prepared in the manner outlined in Examples IV and V. It had an apparent molecular weight of about 90,000 as determined by standard light scattering methods.

381 grams of lauryl methacrylate (1.5 moles), 5 grams of maleic anhydride (0.05 mole) and 16.2 grams of allyl stearate (0.05 mole) were mixed in a three-necked flask fitted with mechanical stirrer, a reflux condenser and thermometer. The mixture was then heated to about 200 F., following which 3 grams of tertiary butyl hydroperoxide and 3 grams of benzoyl peroxide were added during a period of 2 hours, the temperature being maintained at 215-225 F. by heating or cooling as required. The mixture was heated at 215-225 F. for another 18 hours and then stripped by distillation to a temperature of 380 F. at 1 mm. mercury pressure. Approximately 370 grams of maleic anhydride-lauryl methacrylate-allyl stearate copolymer was obtained. The molal ratio of lauryl methacrylate, allyl stearate and maleic anhydride in this copolymer was approximately 30/ 1/ 1.

80 grams of the a llyl stearate maleic anhydride copolymer and grams of the maleic anhydride-lauryl methacrylate-allyl stearate copolymer prepared above were mixed with 16.8 grams of polyethylene glycol having an average molecular weight of about 400 in the reaction vessel described above. 0.34 gram of p-toluene sulfonic acid monohydrate catalyst and suflicient xylene to give slow refluxing at about 300 F. were added. The mixture was refluxed at about 300 F. for about 9 hours with stirring. An additional 39.0 grams of the polyethylene glycol and 0.68 grams of the p-toluene sulfonic acid catalyst were then added, and xylene was allowed to distill ofl until the temperature reached 350 F. The reaction mixture was held at this temperature for about 5 hours, following which the xylene was stripped off by distilling up to 370 F. at 1 mm. mercury pressure.

The product obtained above was a highly viscous, oilsoluble, amber colored polymer. It was further purified by dissolving it in 4 volumes of benzene and then precipitating it from the benzene with 20-25 volumes of methanol. The precipitated polymer was then freed of solvent by distilling up to 370 F. at 1 mm. mercury pressure to give the purified mixture of the partial polyethylene glycol esters of the copolymers of maleic anhydride-allyl stearate, l/l copolymer and lauryl methacrylate-allyl stearate-maleic anhydride 30/ 1/ 1 copolymer.

Example VII A mixture containing a copolymer of maleic anhydride and allyl stearate in equimolar proportions was prepared in this example by the procedure as outlined in Example IV above. As previously, the apparent molecular weight was approximately 90,000. A copolymer of allyl stearate, maleic anhydride and lauryl methacrylate was then prepared by the reaction of lauryl methacrylate with the mix ture containing the maleic anhydride-allyl stearate 1/ l copolymer. This product, as in the case of Example IV, was shown by analysis to be a mixture of 2 copolymers, (A) the allyl stearate-maleic anhydride l/1 copolymer and (B) allyl stearate-maleic anhydride-laury1 methacrylate 1/1/ 15 copolymer.

grams of the mixture of copolymers obtained above was combined with 40.0 grams of polyethylene glycol monolauryl ether. 0.60 gram of p-toluene sulfonic acid catalystwas' then .added. Xylene was distilled oil until the temperature rose to about 350 F. The reaction mixture was then held at this temperature for about hours, following which the xylene was stripped by permitting it to distill off until a temperature of 370 'F. at 1 mm. mercury pressure was reached.

The product obtained above was purified by dissolving it in 4 volumes of benzene and precipitating the polymer with 20-25 volumes of methanol. The precipitated polymer was then freed of solvents by distillation up to 370 F. under a vacuum equal to a pressure of 1 mm. of mercury. This polymer was an amber colored, viscous, oilsoluble material which was shown by analysis to the mixture of: copolymers of (A) allyl stearate-maleic anhydride l/ 1' copolymer and (B) allyl stearate-maleic anhydridelauryl methacrylate 1/ 1/ 15 copolymer each partially esterified with the lauryl ether of polyethylene glycol hav ing a molecular weight of about 550.

Example VIII In this example a. copolymer of allyl stearate and maleic anhydride having a 1/ 1 molal ratio and an apparent molecular weight of about 90,000 was prepared as described in the above examples. 211 grams of the unpurified reaction mixture containing this copolymer was then reacted wi-th 507 grams of inhibitor-free lauryl methacrylate in the same manner as previously described in connection with Examples IV and VII to give a mixture of 2 copolymers, (A) the allyl stearate-maleic anhydride 1/ 1 proximately 550, and 0.5 gram ofp-toluene sulfonic acid:

monohydrate catalyst was added. Thereaction mixture was heated at 320 F. for about two hours and then: at 350 F. for about 14 hours, following the same proced'ureas' given in the above examples. 7 The final product obtained above was stripped. by-vacuum= distillation, extracted with. hot methanol, and then stripped again. It wasa viscous,. amper colored, polymeric material consisting of a mixture of copolymers of (A) maleic anhydride allyl stearate l/l copolymer and (B) maleic anhydride-allyl stearate-lauryl methacrylate copolymerhaving a 1/1/24 molal ratio, each esterified with a polyethylene glycol monomethyl' ether having an average molecular weight-of approximately 550..

Example IX Anallyl stearate-maleic anhydride 1'/1 copolymer was prepared in this example by the same procedure as outlined in the preceding examples.

127grams orf laurylmethacrylate (0.5 mole), 5 grams of maleic anhydride (0.05 mole) and 16.2 gramsof allyl stearate (0.05 mole) were mixed together and heated to-ab-out 220 F. A mixture of 2 grams of tertiary butyl hydroperoxide and 2 grams of benzoyl peroxide was added slowly over a period of about 2 hours, during which time the temperature was maintained at 215225 F. by heating or cooling as it became necessary. Following this addition, the mixture was heated at about 220 F. for about 18 hours and then stripped to 380 F. at 1 mm. of mercury pressure to yield a viscous, amber. colored, oil-soluble polymer containing lauryl methaorylate, maleic anhydride and allyl stearate in a molal ratio of approximately /1/1. V

A mixture of 80' gram's of the allyl stearate-maleic anhydride 1/1 copolymer and 120 grams-of the maleicanhydride-allyl stearate-lauryl methacrylate 1/1/10 00- polymer 'preparedabove was reactedwith l6z8grams of was added. The reaction conditions and purification steps were the same as outlined in Example IV. The finalproduct'was a viscous, amber colored material consisting of a mixture of esterified copolymers of (A) maleic anhydride-allyl stearate 1/1 copolymer and (B) 'maleicauhydride-allyl stearate-lauryl methacrylate 1/ l/ 10 copolymer each esterified with polyethylene glycol monoethyl ether.

'- Example X grams of allyl stearate and maleic anhydride copolymer in l/ 1 molal ratio prepared as described above, grams pearl oil, 21 grams polyethylene glycol 550 molecular weight monomethyl ether, 0.43 gram p-toluene sulforiic acid catalyst and 420 cc. xylene were mixed and heated, atreflux temperature (300 F.) for 9 hours. 50 grams more polyethylene glycol 550 molecular weight monomethyl ether and 0.86 gram catalyst were added and xylene withdrawn to raise reflux temperature to 350 F. The mixture was maintained at this temperature for 5 hours.

The above product was purified by chromatography on silica gel. Solvents were first removed by vacuum distillation and the crude product dissolved in 2% liters of cyclohexane. This solution was passed through a column of silica .gel which was then washed with 2 liters of firesh cyclohexane. The cyclohexane solutions after passingithrough the column, were combined and stripped to yield 120 grams of purified partial polyglycol esters of the allyl stearate and maleic anhydride copolymer.

Mialeic anhydride, lauryl methacrylate and allyl stearate copolymer was prepared as in Example V. 100' grams of polymer was esterified as above using the same quantities, times and temperatures.

After e'sterification, solvents were removed bylvacuum distillation and 142 grams of the crude product was dissolved in 4.4 liters of benzene-cyclohexane mixture of 15:85 ratio. This solutionwas passed through a column of silica gel which was Washedwith 7 liters of the same solvent mixture. '76 grams of the pure partial polyglycol ester was recovered by distillation ofthese solvents. The

ratio of (A) component/ (B) component/polyglycol was Example XI 252 grams of octadecene-l (1 mole) and 98' grams maleic anhydride (1' mole) were mixed and warmed to 215 F. with stirring. A solution of 7 grams ofbenzoyl peroxide in 116 cc. benzene was added over a period of 2 hours. During this time thickening occurred but the mixture remained stirrable. At this time 5 cc. of tertiary butyl hydroperoxide was added and the mixture let stand at 212 F. for a further 18 hours.

7 Crude product was stripped to 350 F. at one millimetertoyield approximately at 1:1 copolymer of octadecene- 1 and maleic anhydride.

100 grams of this product were mixed with 181 gramsof'maleic anhydride, lauryl methacrylate and allyl stearate copolymer, prepared as in Example II. 24 grams of polyethylene glycol 550 molecular weight monomethyl ether,. 0.48 gram p-toluene sulfonic acid catalyst andenoughlxylene' such that reflux occurred at 300 F. Mixture was refluxed at 300 F. with stirring for 9 hours, at which-time a further 55 grams of polyethylene glycol 550'molecular weight monomethyl ether and 0.95 gram ofp-tolhenesulfonic acid catalyst were added and xylene removed'to'raise reflux temperature to 350 F. Heating and stirring were continued at this temperature for 5' hours The crude product was stripped of 'solvents,-297 grams of this crude product were dissolved in xylene (1'- liter) and passed through a silica gel column. The column was washed with 1 liter of fresh xylene and the xylene solutions combined and stripped to yield a mixture of the partial polyglycol esters of octadecene-l and octa'decene-l and maleic anhydride copolymer/maleic anhydride, lauryl methacrylate and allyl stearate copolymer/polyglycol was 36/55/15.

Example XII 98 grams (1 mole) of maleic anhydride and 156 grams (1 mole) of vinyl Z-ethylhexyl ether and 900 cc. benzene were mixed and warmed to reflux. 8 grams benzoyl peroxide in a solution of 50 cc. benzene were added over 10 minutes. The mixture was refluxed with stirring for 4 hours. The polymer was precipitated from benzene with hexane and dried to yield 219 grams of an essentially l/1 copolymer.

75 grams of the above copolymer and 187 grams of maleic anhydride, lauryl methacrylate and allyl stearate copolymer (prepared as in Example V), 22 grams polyethylene glycol 550 molecular weight monomethyl ether, and 0.45 gram p-toluene sulfonic acid were mixed with suflicient xylene to cause refluxing at 300 F., at which temperature the mixture was stirred for 9 hours. An additional 52 grams polyethylene glycol 550 molecular Weight monomethyl ether and 19 grams catalyst were added and xylene removed to raise reflux temperature to 350 F. Stirring at this temperature continued for hours.

203 grams of the crude stripped product were dissolved in a 1:1 mix of benzene and xylene (2 liters) and purified by treatment with silica gel as in Example methacrylate and allyl stearate copolymer/polyethylene glycol 550 molecular weight monomethyl ether was 37/55/10.

Example XV In the same manner as described above, a 1:1 copolymer of vinyl stearate and maleic anhydride was prepared and mixed with one and one-half times its XI to yield 156 grams of the partial polyglycol ester of the mixture of 1:1 maleic anhydride and vinyl Z-ethylhexyl ether copolymer and the 1/ 20/1 maleic anhydride, lauryl methacrylate and allyl stearate copolymer. The ratio of maleic anhydride and vinyl 2-ethylhexyl ether copolymer/maleic anhydride, lauryl methacrylate and allyl stearate copolymer/ polyethylene glycol 550 molecular weight monomethyl ether was 32/55/10.

Example XIII 147 grams maleic anhydride (1 /2 moles), 176 grams vinyl 2-ethylhexyl ether (1.13 moles), and 122 grams allyl stearate (0.38 mole) were mixed and heated to 210 F. 9 grams benzoyl peroxide in 90 cc. benzene were added over 3 /2 hours and held at 217 F. for a further 18 hours. Crude product was stripped to 380 F. at 0.5 millimeter to yield 415 grams of a l/.75/ .25 copolymer of maleic anhydride, vinyl-2-ethylhexyl ether, allyl stearate.

75 grams of this copolymer and 160 grams maleic anhydride, lauryl methacrylate and allyl stearate copolymer (prepared as in Example V) were esterified and purified by the same methods used in Example XII to yield a mixture of the partial polyethylene glycol 550 molecular weight monomethyl-ether esters of the two copolymers. The ratio of maleic anhydride, vinyl-2-ethylhexyl ether and allyl stearate copolymer/maleic anhydride, lauryl methacrylate and allyl stearate copolymer/polyethylene glycol 550 molecular weight monomethyl ether was 34/55/15.

Example XIV Following the procedure of the above examples, a copolymer of methallyl stearate and maleic anhydride was prepared using equimolar proportions. One part of the copolymer thus obtained was mixed with 1.5 parts of maleic anhydride, lauryl methacrylate and allyl stearate copolymer in l/ 20/ 1 mole ratio prepared as in Example V. The mixture was then esterified with polyethylene glycol 550 molecular weight monomethyl ether to give partial ester in which the ratio of methallyl stearate and weight of maleic anhydride, lauryl methacrylate and allyl stearate copolymer in 1/20/1 mole ratio. The mixture was esterified with polyethylene glycol 550 molecular weight monomethyl ether to give a partial ester in which the ratio of vinyl stearate .and maleic anhydride copolymer/maleic anhydride, lauryl methacrylate and allyl stearate copolymer/polyethylene glycol 550 molecular weight monomethyl ether was 35/55/12.

In accordance with the present invention, very superior lubricant compositions are obtained When mixed copolymeric additives of the type described above are added to a base oil of lubricating viscosity. The additives may be employed in any amount sufficient to enhance the detergency and wear inhibiting properties of the compositions. Excellent detergency and wear inhibiting properties are imparted to lubricating oils by the addition of from about 0.1 to 10% by weight based on the composition of the copolymers. The present invention finds its preferred embodiment in lubricant compositions containing the copolymer mixture in amounts of from about 1 to 5%, since such proportions are sufiicient to give detergency and wear protection over prolonged periods of time when the compositions of this invention are employed in an engine, as distinguished from compositions previously employed in the prior art for similar purposes. Another unusual feature of the lubricant compositions of the invention is the fact that the polymers are sufliciently soluble in oil to permit the production of lubricating oil concentrates containing proportions of additive mixture as high as 75% by weight based on the composition of the concentrate. Such concentrates are exceptionally suitable for diluting with lubricating base oils in the preparation of final lubricant compositions.

The efiectiveness of the mixed polymers of the invention as detergents and wear inhibitors is evaluated in a series of engine tests. The method employed in these tests isthat described for the FL-2 Engine Test in the June 21,1948, Report ofthe Co-ordinating Research Council. In accordance with this method, the compounded oil is employed as the crankcase lubricant in a 6- cylinder Chevrolet engineoperated with a low grade gasoline especially prone to cause engine deposits. A jacket temperature or" F. and a crankcase oil temperature of F. are maintained. The engine is operated at 2500 r.p.m. under a load of 45 brake horsepower for 40 hours. Cold engine conditions normally experienced in city driving are thus closely simulated. At the end of each test the engine is dismantled and the amount of engine deposits on the piston determined and expressed as the Average Piston Varnish Rating. This value is obtained by visually rating the amount of deposit on each piston and averaging the individual ratings so obtained for the various pistons on a scale of 0 to 10 with 10 representing the obsence of any deposits.

The piston ring wear encountered with the various lubricant compositions employed in these tests is also illustrative of the efiectiveness of the compositions. This wear, measured in terms of milligrams per hour, is considered to be satisfactory if it does not exceed 4 milligrams per hour.

The lubricant compositions in the tests contain a solvent refined SAE-30 mineral lubricating oil as a base oil with additives as indicated in the following table of test results. Other oils of lubricating viscosity are similarly benefited when compounded with additives to produce lubricant compositions according to the present maleic anhydride copolymer/maleic anhydride,; lauryl 75 invention.

TABLE I Percent Average Piston Proportions oi'(A), byweight piston ring (A) Component (B) Component Polyalkylene glycol (B) and polyalkylene additive varnish wear,

glycol lncornrating mgJhr.

position None (base oil alone) None (base oil alone) None (base oil alone) None (base oil alone) 3.5 5.0 Allyl stearatemaleic anhy- Lauryl methac-rylatemaleio Polyethylene glycol, 550 35/54/11 2.5 8.5 2.8

dride, 1/1 copolymer. anhydride, /1 copolymer. 11%;)18 weight monomethyl e 181. Lauryl methacrylatemaleio Polyethylene glycol, 400 37/56/7 2.5 7.8 3.2

anhydride, /1 copolymer. mole weight. Lauryl methacrylatemaleic Polyethylene glycol, 550 38/57/5 2.5 6.0 3.7

anhydride, 10/1 copolymer. ntigle weight monomethyl e er. None Lauryl methacrylatemaleie do 95.8/42 2.5 5.0 3.7

anhydride, 20/1 copolymer. Allyl stearatemaleic anhyne n 80/20 2.5 4.1 4.0

'dride,1l1 copolymer.

Do Allyl stearatemalelc anhyo 36/55/ 2.5 9.7 2.7

drrde-lauryl methacrylate, 1/lll5copolyme1". f D do o 36/55/13 1.5 8. 6 3. 1 Do Allyl stearatemaleic anhydo 37/56/7 2.5 9.5 2.9

dridelauryl 'methaerylate; 1/1/20 copolymer. Do Allyl stearatemaleic anhy- Polyethylene glycol, 400 38.0/57.9/3.5. 2.5 8.5 3.2

dridelauryl methacrylate, mole weight. 1/1/30 copolymer. Do Allyl stearatemaleic anhy- Polyethylene glycol, 550 34/51.5l14.5 2.5 9.2 2.9.

dride lauryl methyacrylate, mole weight monolauryl 1/1/15 copolymer. dialkyl ether. Do Ally! stearatemaleic anhy- Polyethylene glycol, 550 38.5/57.5/4 1.5 6.5 3.0

dridelauryl methacrylate, mole weight monomethyl 1/1/10 copolymer. ether. Do do do 37.8/56.7/ 2.5 7.8. 3.5 Do None Polyglycol, 550 mole weight 88.5/1L5 2.5 4.5 3.9

monomethyl ether. None Allyl stearatemalele why .do 91/9 2.6 5.5 3.5

dridelauryl methacrylate, 1/1/20 copolymer. Vinyl stearatemaleic enhyrln do 38/58/4 2.5 7.2 3.7

dride, 1/1 copolymer. Allyl stearatemaleic anhy- Allyl stearatemaleic anhy- Polyethylene glycol, 550 30/60/10 2.5 7.7 3.6

dride, 1/l copolymer. drldevinyl-2-ethyl-hexoate, mole weight monomethyl ill/20 copolymer. ether. Ootadecene-l-maleie anhy- Maleio anhydride, lauryl n 34/55/1 1.5 7.2

dride, lll copolymer. methaerylate and allylstearate copolymer, 20/1/1 copolymer. Vinyl 2-ethylhexyl etherrln do 32/55/10 1.5 7.1

maleic anhydride, l/l oopolymer. Vinyl Z-ethylhexyl etherallyl do do 34/55/15 1. 5 7.1

stearatemaleic anhydride, 0.75/0.25/1 copolymer.

As shown by the illustrative test data of the above table, the lubricant compositions of the invention are outstanding detergents and wear inhibitors under the most severe conditions encountered'in the low temperature operation of internal combustion engines. The base oil alone gives an average piston varnish rating and piston ring wear of 3.5 and 5.0, respectively, whereas the improved compositions of the invention containing the illustrative polymeric additives give results in the order'of 9.7 and 2.7, respectively. Excellent results of 8.5 varnish and 2.8 wear are also obtained in mixtures where the unsaturated alcohol ester is omitted from the (B) component.

It may also be seen from the above test results that the unusual effectiveness of the lubricant compositions of the invention is entirely unexpected and unpredictable. Although the polyethylene glycol esters of the allyl stearate-maleic anhydride (A) component and the allyl stearate-maleic anhydride-lauryl methacrylate or lauryl methacrylate-maleic anhydride (B') componentare fairly effective when employed separately in the lubricant compositions, compared to the base oil alone, they are only about one-half as effective as the copolymer mixture containing lubricant compositions in accordance with, the present invention.

In addition to the foregoing illustrations of the polymeric compositions according to the invention, the following examples aresubmitted to show the methods of preparing mixed copolymers containing polar groups other than the free carboxylic acid groups referred to above. The first of these methods deals with the preparationof polar group-containing, mixed copolymers of the type listed in Examples XVLXXV and XXII to XXXV, inclusiveof the following table. The (A) and (B) copolymers and polyalkylene glycol are combined in the manner already described in the previous examples. The introductionof the polar groupcontaining component, hereinafter referred to as component (C), is then accomplished by subjecting the glycol esterified (A) and (B) copolymers to the usual reactions. For example, amide and alkoxy derivatives are prepared by reacting the mixed copolymers of (A) and (B) esterified by polyglycol with the amineor alcohol having the desired characteristics which will produce the corresponding amide or alkoxy group. The reaction is carried out in a suitable solvent such as xylene at temperatures in the range from 270 to 400 F. using an acid catalyst such as p toluene sulfonic acid. Because of the relatively low rate of reaction usually encountered with these products, a 25 to 100%. excess of the amine or alcohol is employed and the unreacted portion is removed by distillation where the reactant is volatileor by precipitation ofthe product from the hydrocarbonsolvent with apolymeric antisolvent. Where poly-functional amines or alcohols such as ethylenediamine or ethylene glycol are employed for the (C) component, a relatively dilute reaction medium is favored (30 to solvent) to control cross-linking reactions which, if permitted to occur toany appreciable extent, may produce hydrocarbon-insoluble, gel-like polymers. Thio esters and substitutedthio esters are pro- 21 duced in a similar manner. Ammonium salts are prepared simply by adding the amine to a solution of the glycol-esterified mixed copolymers and warming at 200 to 300 F. for a short period until the reaction is complete. In other preparations, particularly where a monofunctional polar-type substituent is employed, the (C) component is substituted on the mixture of (A) and (B) copolymers or on the (A) or (B) copolymer alone prior to reaction of the (A) and (B) mixture with the polyalkylene glycol.

In the second series of preparations, Examples XXVI to XXXI, inclusive, the method of preparing mixed copolymers containing polar group constituents follows a different route. In this type of synthesis the polar group component (C) is added to copolymer (A). and/or (B) during its preparation. Since the maleic anhydride content of copolymer (A) is ordinarily much higher than that of copolymer (B), as already mentioned, it is generally preferred to make the substitution of the polar group component (C) in copolymer (A). In a preparation of this type, the copolymer (A) or (B) is prepared by the usual methods already described in connection with the preceding examples. A portion of the maleic anhydride, however, is replaced by a suitable derivative of the anhydride such as the imide, the ha1f-amide, the diamide, alkyl amides, thio esters, esters, ammonium salts and the like. The resulting copolymer of (A) and/or (B) thus includes the (C) component. The preparation of the final product, the mixed copolymers, is then accomplished by completing the reaction of (A) and/or (B) and (C) copolymers with the remaining unused copolymers, that is, (A) or (B) and the polyalkylene glycol or ether thereof.

The choice between the above two methods for the preparation of mixed copolymers in accordance with the present invention is generally controlled by ease of syn thesis of the maleic acid anhydride derivative and its polymerization rate, or the ease with which it copolymerizes with the other monomers involved.

The above methods will yield novel products, as illusindicated properties to lubricant compositions.

TABLE II Propor- Percent tions of by Aver- Piston Example Maleie anhydride (A), (B) weight age ring No. (A) Component (B) Component Polyalkylene glycol polar substituent polyaddipiston wear,

group (O) alkylene tive in varnish rug/hr.

glycol comporate and (C) sltion XVI Allyl stearete-maleic Lauryl methecrylate- Polyethylene glycol, Octadecyl emidi 35/52/7/6 2. 5 7. 5 3. 1

anhydride, 1/1 malelc anhydrlde, 20/1 550 mole Weight polymer. copolymer. monomethyl ether.

XVII. .-...do ..do ..do Octadecyl ammon um 35/52/7/6 2. 7. 8 3.8

XVIII- do Lauryl methacrylate- Polyethylene glycol, Hydroxyethyl am1do.. 33/50/12/5 2. 5 8.0 2. 9

maleic anhydride, 10/1 550 mole weight copolymer. mono-laurel ether.

XIX do Lauryl methacrylatedo Tetraethylene pent- 30/55/12/3 2. 5 6. 9 3. 9

maleic anhydride, 30/1 ammonium. copolymer. XX do Lauryl methacrylate- Polyethylene glycol, 2,2,2-trihydroxy 34/58/5/3 2. 5 8. 4 3, 8

maleic anhydride, /1 400 mole weight. methylpropanoxy copolymer. (pexitagrythritol es .er XXI do Allyl stearate-malele an- Poly-1,2-propylene 2-mercapto propoxy..- /53/10/2 2. 5 6.5 3. 9

hydride-laur l methglycol, 350 mole acrylate, 1/1 15 copolweight.

mer. XXII fin y do Polyethylene glycol, Trlethanol ammoni- 39/48/7/6 2. 5 8.7 3. 0

550 mole weight um. mono-lauryl ether.

XXIII. Vinyl stearate-maleic Allyl stearate-maleic an- Poly-1,2-propylene 3-morpholme amido-.. 33/57/6/4 2. 5 7. 2 3. 3

anhydride, l/l cohydride-vinyl Z-ethylglycol, 500 mole polymer. hexoate, 1/1/30 copolweight monoethyl ymer. ether. XXIV- do do --do 2,2-hydroxymethyl 3- 33/57/6/4 2. 5 8. 5 3, 1

. Y oleoxy, propanoxy. XXV .do Vinyl stearate-maleic Polyethylene glycol, N-(2-emmo ethyl) 25/61/11/3 2. 5 9. 0 3.1

anhydride-cetyl aeryl- 550 mole weight amldo. ate, 111/18 copolymer. monomothyl ether.

Proportions of (A), and. polyalkylene glycol XXVI. Allyl stearate-maleic Lauryl methacrylate- Polyethylene glycol, Amide-see (A) com- 37/55/8 2. 5 8. 5 3.0

anhydride-malearnic maleic anhydride, 20/1 400 mole weight. ponent. acid. 1/0.9 0.l. copolymer.

XXVII- Allyl stearate-maleic Allyl stearate-rnalelc an- Polyethylene glycol, lmide and amido-see 40/54/6 2. 5 D. 1 2. 9

anhydride-maleihydride-lauryl aeryl- 750 mole weight (A) component. mide, l/0.9/0.1. ate, 1/1/30 copolymer. monolauryl ether.

XXVIII.-. Methallyl stearate- Methallyl stearate- ..do Isobutyl amide-see 36/52/12 2. 5 9. 2 2.9

maleic anhydridemaleic anhydride- (A) component. isobutyl maleamide, lauryl acrylate, 1/1/30 1/0.8/0.2 copolymer. copolymer.

XXIX. Methallyl stearatedo do... 2-hydroxy ethoxy 27/63/10 1. 6 9. 0 3. 1

maleic anhydridesee (A) component. ethylene glycol monomaleate, noes/0.15 copolymer.

XXX Vinyl 2ethyl-hexoate- Allyl stearate-maleic au- Polyethylene glycol, Amido-see (A) 40/56/4 2. 5 8. 7 3. 3

maleic anhydrldehydride-1am l meth- 550 mole weight component. oetyl maleamate, acrylete, 1/1 30 copolmonomethyl ether. 1/0.95/0.05 ymer. copolymer.

XXXI- Allyl stearate-maleic Lauryl methacrylete- Polyethylene glycol, Free acid-see (A) 34/51/15 2. 5 8. 9 3.7

anhydride-malelc diisobutylenemalelc 400 mole weight. component. acid, 1/0.5/0.2 anhydrlde, 15/10/1 copolymer.

I copolymer.

Percent 5552 y Aver- Piston Example Malelc anhydride (A) (B) weight age Img No. (A) Component (B) Component Polyalkylene glycol polar substituent addlpiston wear,

group (O) alkylene tlve 1n varnish mg./hr.

compora e glycol sition XXXII--- Allyl stearate-maleie Vinyl trimethyl-nonyl Polyethylene glycol, 2-ethylhexyl amido.. 42/45/8/5 2. 5 7. 5 3.6

anhydride, 1/1 ether-dilauryl maleate 400 mole weight copolymer. maleic anhydride, monolauryl ether.

/9/1 copolymer. XXXIIL- do Cetyl phenoxyethyl Polyethylene glycol, Octyl thlO 40/42/10/8 2. 5 8.4 3.9

methacrylate maleic 800 mole weight 31].}1ydlld6, 20/1 00- monooctyl ether.

0 mer. XXXIV do vi l ayl stearyl ketone- Polyethylene glycol, Dlhydroxyethyl /70/11/4 2. 5 V 7. 9 4. 0

maleic anhydride, 15/1 400 mole weight. ethylene dlam- V copolymer. 111011111111- XXXV do Vinyl stearyl ketone- Polyethylene glycol, 2-1J1tr0 BthOXY 15/70/9/6 2.5 7.2 3.8

dinonyl phenoxyethyl 550 mole welght aerylate-maleic -anmonomethyl ether. hydride, 10/12/1 c0- polymer.

In the above illustrated copolymers, the (C) component is present in a weight ratio of up to 2 parts of (C) for each part of the (B) copolymer; preferably, as illustrated by the above test data, the proportion of the (C) component will vary from about 0.05 to 1.0 for each'part of the (B) component.

The compositions of the invention may also include other agents such as oiliness agents, viscosity index improvers, pour point depressants, blooming agents, peptizing agents, etc., as are known to the art. Although the compositions have been primarily described as crankcase lubricants for internal combustion engines, they are also useful as turbine oils, hydraulic fluids, instrument oils, oils for grease manufacture, ice machine oils and the like.

This application is a continuation-in-part of Stewart, Wilgus, and Stuart application Serial No. 549,871, filed November 29, 1955, and now abandoned, which in turn is a continuation-in-part of Stewart, Wilgus, and Stuart application Serial No. 479,224, filed December 31, 1954 (now abandoned), and of Stuart, Stewart, and Wilgus application Serial No. 549,870, filed November 29, 1955 and now abandoned, which in turn is a continuation-inpart of Stuart, Stewart, and Wilgus application Serial No. 479,239, filed December 31, 1954 (now abandoned).

We claim:

1. A lubricant composition comprising a major portion of an oil of lubricating viscosity and a minor portion, suflicient to enhance the detergent characteristics of the composition, of an oil-soluble mixture of (A) the copolymer of a monomer selected from the group consisting of 1) a fatty acid ester of an unsaturated alcohol, said fatty acid containing 8 to 30 carbon atoms and said unsaturated alcohol being selected from the group consisting of a and ,B-unsaturated alcohols containing up to 7 carbon atoms, (2) l-olefins of 6 to 24 carbon atoms and (3) vinyl and allyl alkyl ethers having 4 to 22 carbon atoms in the alkyl group with maleic anhydride, said monomers being in approximately 1:1 molar ratio, and (B) the copolymer of monomers selected from at least the first two classes of the groups consisting of (1) maleic anhydride (2) a higher alkyl ester of an. a o-unsaturated monocarboxylic acid of from 3 to 8 carbon atoms of which the alkyl group contains from 8 to 30 carbon atoms and (3) a fatty'acid ester of an unsaturated alcohol in which the fatty acid contains up to 30 carbon atoms and the unsaturated alcohol is a member of the group consisting of a and fl-unsaturated alcohols containing up to carbon atoms, at least one of said (A) and (B) copolymers being partially esterified with a member of the group consisting of polyalkylene glycols having a molecular weight betweenabout 106 and 10,000 and alkyl ethers thereof in which the alkylene groups contain from 2 to 7 carbon atoms each and the alkyl groups contain from 1 to 30 carbon atoms each and said (A) and (B) copolymers being in the weight ratio of 0.15 to 5 parts of (A) for each part of (B).

2. A lubricant composition comprising a major portion of an oil-of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of an allyl ester of a fatty acid, said fatty acid containing 8 to '30 carbon atoms, with maleicanhydride in approximately 1:1 molar ratio and (B) the copolymer of maleic anhydride and a higher alkyl ester of a,/3-unsaturated monocarboxylic acid of from 3 to 8 carbon atoms, in which the alkyl group contains from 8 to 30 carbon atoms 'the total maleic anhydride of said a (A) and said (B) copolymers being 2 to esterified with a polyethylene glycol having a molecular weight between about 200 and about 2000 and said (A) and (B) copolymers being in the weight ratio of 0.15 to 5 parts of (A) for each part of (B).

3. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10%, by weight, of an oil-soluble-mixture of the copolymerof allyl stearate with maleic anhydride in approximately 1:1 molar ratio and the copolymer of maleic anhydride and lauryl methacrylate, the total maleic anhydride of said mixture of copolymers being 275% esterified with a polyethylene glycol monoalkyl ether having a molecular weight between about 200 and 2,000, and from 1 to 30 carbon atoms in the alkyl group, and said copolymers being in the weight ratio of 0.15 to 5 parts of the allyl stearate and maleicanhydride copolymer for each part of the maleic anhydride and lauryl methacrylate copolymer.

4. A lubricant composition comprising a major portion of an oil of lubricating viscosity and a minor portion, suflicient to enhance the detergent characteristics of the composition, of an oil-soluble mixture of (A) the copolymer of a monomer selected from the group consisting of 1) a fatty acid ester of an unsaturated alcohol, said fatty acid containing 8 to 20 carbon atoms and said unsaturated alcohol being selected from the group consisting of oz and S-unsaturated alcohols containing up to 7 carbon atoms, (2) l-olefins of 6 to 24 carbon atoms and (3) vinyl and allyl alkyl ethers having 4 to 22 carbon atoms in the alkyl group with maleic anhydride, said monomers being inapproximately 1:1 molar ratio, and (B) the copolymer of monomers selected from each of the groups consisting of (1) maleic anhydride ('2) a higher alkyl ester of an cap-unsaturated monocarboxylic acid of from 3 to 8 carbon atoms of which the alkyl group contains from 8.to 30 carbon atoms and (3)" a fatty acid ester of an unsaturated alcohol in which therfatty acid contains up to 30 carb'on atoms and the-unsaturated alcohol -is a member 25 of the group consisting of a and fi-unsaturated alcohols containing up to 20 carbon atoms, at least one of said (A) and (B) copolymers being partially esterified with a member of the group consisting of polyalkylene glycols having a molecular Weight between about 106 and 10,000 and alkyl ethers thereof in which the alkylene groups contain from 2 to 7 carbon atoms each and the alkyl groups contain from 1 to 30 carbon atoms each and said (A) and (B) copolymers being in the weight ratio of 0.15 to parts of (A) for each part of (B).

5. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to by weight of an oil-soluble mixture of (A) the copolymer of a fatty acid ester of unsaturated alcohol, said fatty acid containing 8 to 30 carbon atoms and said unsaturated alcohol being selected from the group consisting of a and fi-unsurated alcohols containing up to 7 carbon atoms with maleic anhydride and (B) the copolymer of (1) maleic anhydride, (2) a higher alkyl ester of an a,;3-unsaturated monocarboxylic acid of from 3 to 8 carbon atoms of which the alkyl group contains from 8 to 30 carbon atoms and (3) a fatty acid ester of an unsaturated alcohol in which the fatty acid contains 8 to 30 carbon atoms and the unsaturated alcohol is a member of the group consisting of a and [SJ-unsaturated alcohols containing up to 7 carbon atoms, at least one of said (A) and (B) copolymers being partially esterified with a polyalkylene glycol having a molecular weight between 106 and about 10,000 in which the alkylene groups contain from 2 to 7 carbon atoms each and said (A) and (B) copolymers being in the weight ratio of 0.15 to 5 parts of (A) for each part of (B).

6. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of an allyl ester of a higher fatty acid of from 8 to 30 carbon atoms with maleic anhydride and (B) the copolymer of (l) maleic anhydride, (2) a higher alkyl ester of an a,B-unsaturated monocarboxylic acid of from 3 to 8 carbon atoms of which the alkyl group contains from 8 to 30 carbon atoms and (3) an allyl ester of a higher fatty acid of from 8 to 30 carbon atoms, at least one of said (A) and (B) copolymers being partially esterified with a polyethylene glycol having a molecular weight between about 200 and about 2,000 and said (A) and (B) copolymers being in the weight ratio of 0.15 to 5 parts of (A) for each part of (B).

7. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of an allyl ester of a higher fatty acid of from 8 to 30 carbon atoms with maleic anhydride and (B) the copolymer of (1) maleic anhydride, (2) a higher alkyl ester of an a,fi-unsaturated monocarboxylic acid of from 3 to 8 carbon atoms in which the alkyl group contains from 8 to 30 carbon atoms and (3) an allyl ester of a higher fatty acid of from 8 to 30 carbon atoms, at least one of said (A) and said (B) copolymers being partially esterified with a polyethylene glycol monoalkyl ether having from 1 to 30 carbon atoms in the alkyl group and a molecular weight between about 200 and about 2,000 and said (A) and (B) copolymers being in the weight ratio of 0.15 to 5 parts of (A) for each part of (B).

8. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of an allyl ester of a higher fatty acid of from 8 to 30 carbon atoms with maleic anhydride in approximately 1:1 molar ratio and (B) the copolymer of (1) maleic anhydride, (2) a higher alkyl ester of an 0a,,8-1111- saturated monocarboxylic acid of from 3 to 8 carbon atoms in which the alkyl group contains from 8 to 30 carbon atoms and (3) an allyl ester of a higher fatty acid of from 8 to 30 carbon atoms, said copolymer containing from about 0.25 to 4 moles of allyl ester for each mole of maleic anhydride, and the molar ratio of the higher alkyl ester being from about 5 to 50 times that of the combined maleic anhydride and allyl ester, said (A) and said (B) copolymers being present in approximately equal parts and partially esterified with a polyethylene glycol having a molecular weight between about 200 and about 2,000, the total molecular weight of the copolymer being at least 2,000.

9. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of allyl stearate with maleic anhydride in approximately 1:1 molar ratio and (B) the copolymer of (1) maleic anhydride, (2) lauryl methacrylate and (3) allyl stearate, said copolymer containing about 0.25 to 4 moles of allyl stearate for each mole of maleic anhydride, and the lauryl methacrylate being present in molar proportions of 5 to 50 times that of the combined maleic anhydride and allyl stearate, said (A) and said (B) components being partially esterified with a polyethylene glycol monoalkyl ether having from 1 to 30 carbon atoms in the alkyl group and a molecular weight between 200 and about 2,000, from about 0.04 to 1.5 mole of polyethylene glycol being present for each mole of maleic anhydride in component (A) and the total molecular weight of the copolymer mixture being at least 2,000.

10. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of vinyl stearate with maleic anhydride in approximately 1:1 molar ratio and (B) the copolymer of (1) maleic anhydride, (2) lauryl methacrylate and (3) allyl stearate, said copolymer containing about 0.25 to 4 moles of allyl stearate for each mole of maleic anhydride, and the lauryl methacrylate being present in the molar proportions of 5 to 50 times that of the combined maleic anhydride and allyl stearate, said (A) and said (B) components being partially esterified with a polyethylene glycol monoalkyl ether having from 1 to 30 carbon atoms in the alkyl group and a molecular weight between 200 and about 2,000, from about 0.04 to 1.5 moles of polyethylene glycol being present for each mole of maleic anhydride in component (A) and the total molecular weight of the copolymer mixture being at least 2,000.

11. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of octadecene-l with maleic anhydride in approximately lzl molar ratio and (B) the copolymer of (1) maleic anhydride, (2) lauryl methacrylate and (3) allyl stearate, said copolymer containing about 0.25 to 4 moles of allyl stearate for each mole of maleic anhydride, and the lauryl methacrylate being present in the molar proportions of 5 to 50 times that of the combined maleic anhydride and allyl stearate, said (A) and said (B) components being partially esterified with a polyethylene glycol monoalkyl ether having from 1 to 30 carbon atoms in the alkyl group and a molecular weight between 200 and about 2,000, from about 0.04 to 1.5 moles of polyethylene glycol being present for each mole of maleic anhydride in component (A) and the total glgggzular weight of the copolymer mixture being at least 12. A lubricant composition comprising a major portion of an oil of lubricating viscosity and from about 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of vinyl 2-ethyl hexyl ether with maleic anhydride in approximately 1:1 molar ratio and (B) the copolymer of (l) maleic anhydride, (2) lauryl methacrylate and (3) allyl stearate, said copolymer containing about 0.25 to 4 moles of allyl stearate for each mole of maleic anhydride, and the lauryl methacrylate being present in molar proportions of 5 to 50 times that of the combined maleic anhydride and allyl stearate, said (A) and said (B) components being partially esterified with.

a polyethylene glycol monoalkyl ether having from 1 to;30 carbon atoms in the alkyl group and a molecular weight between 200 and about 2,000, from about 0.04 to 1.5 moles of polyethylene glycol being present for each mole of maleic anhydride in component (A) and the total molecular Weight of the copolymer mixture being at least 2,000.

13. A lubricant composition comprising a major portion of an oil of lubricating viscosity and fromabout 0.1 to 10% by weight of an oil-soluble mixture of (A) the copolymer of allyl stearate and vinyl 2-ethylhexyl ether with maleic anhydride in approximately 0.25:0.75:1 molar ratio and (B) the copolymer of (1) maleicanhydride, 2) lauryl methacrylate and (3) allyl stearate, said copolymer containing about 0.25 to 4 moles of allyl stearate for each'mole of maleic anhydride, and the lauryllmethacrylatebeing present in molar proportions of 5 to 50 times that of the combined maleic anhydride and allyl stearate, said (A) and said (B) components being partially esterified with a polyethylene glycol monoalkyl ether having from 1 to 30 carbon atoms in the alkyl group and almplecular weight between 200 and about 2,000, from about.'0.04'to 1.5 moles of polyethylene glycol being presentfor each mole of maleic anhydride in component (A) and the total molecular weight of the copolymer mixture being at least 2,000.

References Cited in the file of this patent UNITED STATES PATENTS 2,615,844 Giammaria Oct. 28, 1952 2,615,845 ,Lippincottet al. Oct. 28, 1952 2,684,355 Van Horne July20, 1954 2,694,685 Bartlett 'N0v. 16, 1954 2,704,277 Giammaria Mar. 15, 19.55 2,731,448 Bauer et al Jan. 17, 1956 2,737,496 Catlin Mar. 6, 1956 FOREIGN PATENTS 768,701 Great Britain Feb. 20,1957

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