Highly grafted, multi-functional olefin copolymer VI modifiers

摘要

An olefin copolymer which comprises the reaction product of an acylated olefin copolymer and a polyamine, wherein the acylated olefin copolymer comprises an olefin copolymer having grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer and wherein the olefin copolymer has a number average molecular weight of from 20,000 to 150,000. The copolymer is used as an additive in lubricating oil compositions where it acts as a viscosity modifier.