Ethylene copolymer viscosity index improver dispersant additiveuseful in oil compositions

Abstract From the Canadian patent

Oil-soluble derivatized ethylene copolymers, derived from about 15 to 90 wt. % ethylene and one or more, C3 to C28 alpha-olefins e.g. propylene, which are, grafted, preferably solution-grafted under an inert atmosphere and at elevated temperatures and in the presence of a high-temperature decomposable free-radical initiator with an ethylenically-unsaturated dicarboxylic acid material and thereafter reacted with a polyamine having at least two primary amine groups, and a carboxylic acid to form carboxyl-grafted polymeric imide, usually maleimide derivatives are subsequently reacted with a C12 to C18 hydrocarbyl substituted dicarboxylic acid anhydride preferably a C12 to C18 hydrocarbyl …