LUBRICATING OIL COMPOSITION AND PROCESS FOR PRODUCING SAME

Une composition d'huile de lubrification composee d'un copolymere greffe soluble dans l'huile, preparee par greffage d'une petite quantite d'un monomere de greffe choisi parmi le groupe comprenant des esters satures d'acides monocarboxyliques non satures, d'esters non sature s d'acides carboxyliques satures, et de composes epoxy non satures sur un copolymere n'ayant pratiquement aucune liaison double carbone-carbone exprimee en terme de valeur iode, n'ayant pas de groupe fonctionnel contenant de l'oxygene et ayant un poids moleculaire moyen d'environ 5000 a 100000 choisis parmi le groupe de produits d'hydrogenation de copolymeres d'(Alpha)-olefines contenant entre 2 et 20 atomes de carbone, des copolymeres de styrene et d'(Alpha)-olefine contenant de 2 a 20 atomes de carbone, et des copolymeres de styrene et de diolefines; et un procede pour sa production. PCT No. PCT/JP79/00289 Sec. 371 Date Jul. 14, 1980 Sec. 102(e) Date Jul. 14, 1980 PCT Filed Nov. 13, 1979 PCT Pub. No. WO80/00976 PCT Pub. Date May 15, 1980.A lubricating oil composition comprising a major proportion of a lubricating oil, and an oil-soluble graft copolymer, said graft copolymer being prepared by grafting a small amount of a grafting monomer selected from saturated esters of unsaturated monocarboxylic acids, unsaturated esters of saturated carboxylic acids and unsaturated epoxy compounds to a trunk copolymer which is substantially free from an oxygen-containing functional group and a carbon-carbon double bond determined from its iodine value and has a number average molecular weight of about 5,000 to about 100,000, said trunk copolymer being selected from copolymers of alpha-olefins having 2 to 20 carbon atoms, copolymers of styrene and alpha-olefins having 2 to 20 carbon atoms and hydrogenated products of copolymers of styrene and diolefins. A process for preparation of said composition is also provided.