| abstract |
Polyalkyl acrylates and methacrylates, suitable for improvement of the viscosity index, are used as oil additives imparting improved dispersant and detergent effects in diesel and gasoline engines, said polyalkyl acrylates or methacrylates being copolymers comprising from 80 to 99.5 parts by weight of alkyl acrylates of methacrylates of the formula <IMAGE> wherein R is hydrogen or methyl and R1 is alkyl having from 6 to 24, and preferably from 8 to 20, carbon atoms, together with from 0.5 to 20 parts by weight of at least one functionalized alkyl methacrylate of the formula <IMAGE> wherein R1 is hydrogen or methyl and R2 is alkyl having from 2 to 6 carbon atoms and substituted with at least one OH group, or is a polyalkoxylated group of the formula <IMAGE> wherein R3 and R4 are hydrogen or methyl, R5 is hydrogen or alkyl having from 1 to 40 carbon atoms, and n in an integer from 1 to 60, the sum of the monomers of formulas (I) and (II) being 100 parts by weight, and optionally further comprising from 0 to 20 parts by weight of one or more monomers of the formula <IMAGE> wherein R'' is hydrogen or methyl and R6 is alkyl having from 1 to 5 carbon atoms. Such copolymers are conveniently prepared by copolymerization, advantageously in an oil-compatible vehicle in the presence of an olefin copolymer to form a concentrated emulsion additive. |