Patent GB-757915-A (GB)
Title: Lubricant composition
Filed: 1953-08-20
Abstract: Oil compositions having improved resistance to oxidation comprise a major proportion of a normally oxidizable oil together with (1) from 0.5 to 10 per cent of a copolymer of a higher alkyl ester of an alpha, beta-olefinically unsaturated acid having the structural formula <FORM:0757915/IV(a)/1> with an N-substituted amide of such an acid having the structural formula <FORM:0757915/IV(a)/2> in which R1 and R2 represent hydrogen atoms or methyl groups, R3 represents an alkyl group containing at least 8 carbon atoms, R4 represents a hydrogen atom or a substituted or unsubstituted hydrocarbon radical, and R5 represents a substituted or unsubstituted hydrocarbon radical; and (2) from 0.1 to 5 per cent of at least one anti-oxidant selected from diaryl amines and polyhydric aromatic compounds.  Amongst the unsaturated esters and amides specified, preferred are 2-(ethyl hexyl) acrylate and methacrylate, dodecyl methacrylate and crotonate, N,N-dibutyl acrylamide and methacrylamide, N-2-ethylhexyl acrylamide and crotonamide, N - 2 - hydroxyethyl methacrylamide and N-nonyl methacrylamide.  Amongst the diaryl amines and polyhydric aromatic compounds specified, preferred are phenylalpha - naphthylamine, p - hydroxydiphenylamine, diphenylamine, phenothiazine, 2,2-di-(p-hydroxyphenyl) propane, p-tert.-butyl catechol, and di-beta-naphthol.  The compositions may also contain additional ingredients such as polyvalent metal phenates, sulphonates and thiophosphates.  The oils employed may be natural hydrocarbon lubricating oils or synthetic oils such as alkylated waxes, hydrogenated polymers of hydrocarbons, the condensation products of chlorinated alkyl hydrocarbons with aryl compounds, polymers of ethylene and/or propylene oxides, the products obtained by the etherification and/or esterification of alkylene oxide polymers, for example the acetate of the 2-ethylhexanol initiated polymer of propylene oxide, and di(2-ethylhexyl) sebacate.  The copolymers may be prepared by bulk, emulsion or solution methods with the aid of heat, light and/or catalysts such as benzoyl, acetyl, di-tertiary amyl and lauroyl peroxides, hydrogen peroxide, alkali metal perborates and persulphates, boron trifluoride, 1,11-azodicyclohexane carbonitrile and alpha, alpha1-azodiisobutyronitrile.  The copolymers may be prepared directly by the copolymerization of the amide and ester monomers, or by the after-treatment of a polymer to produce the desired amide/ester copolymer, for example a dodecylmethacrylate/N - 2 - hydroxyethyl methacrylamide copolymer is made by treating a dodecyl methacrylate/methacrylic acid copolymer with ethanolamine.ALSO:Lubricating oil compositions having an improved resistance against oxidation comprise a major proportion of a normally oxidizable oil together with (1) from 0.5 to 10 per cent of a copolymer of a higher alkyl ester of an alpha, beta-olefinically unsaturated acid having the structural formula:- <FORM:0757915/III/1> with an N-substituted amide of such an acid having the structural formula:- <FORM:0757915/III/2> in which R1 and R2 represent hydrogen atoms or methyl groups, R3 represents an alkyl group containing at least 8 carbon atoms R4 represents a hydrogen atom or a substituted or unsubstituted hydrocarbon radical, and R5 represents a substituted or unsubstituted hydrocarbon radical, and (2) from 0.1 to 5 per cent of at least one anti-oxidant selected from the group consisting of diaryl amines and polyhydric aromatic compounds.  Amongst the unsaturated esters and amides specified preferred are 2 - (ethylhexyl) acrylate and methacrylate dodecyl methacrylate and crotonate N, N - dibutyl acrylamide and methacrylamide N - 2 - ethylhexyl acrylamide and crotonamide, N - 2 hydroxyethyl methacrylamide and N - nonyl methacrylamide. Amongst the diaryl amines and polyhydric aromatic compounds specified preferred are phenylalpha naphthylamine, diphenylamine, p-hydroxydiphenylamine, phenothiazine, 2, 2 - di (p - hydroxyphenyl) propane, p - tert. - butyl catechol and di - beta - naphthol.  The oil compositions may also contain additional ingredients such as polyvalent metal phenates, sulphonates and thiophosphates.  The oils employed may be natural hydrocarbon lubricating oils or synthetic oils such as alkylated waxes, hydrogenated polymers of hydrocarbons, the condensation products of chlorinated alkyl hydrocarbons with aryl compounds, polymers of ethylene and/or propylene oxides, the products obtained by the etherification and/or esterification of alkylene oxide polymers, for example the acetate of the 2 - ethylhexanol - initiated polymer of propylene oxide, and di (2 - ethylhexyl) sebacate.