Stabilised imide graft of ethylene copolymeric additives for lubricants, process for their preparation, process for stabilising additive concentrates for lubricants based on the imide graft ethylene copolymer and lubricating oil compositions comprising the stabilised additive

摘要

Oil-soluble, derivatized ethylene copolymers used as additives for lubricants, derived from about 2 to 98 weight % ethylene, and one or more C, to C₂₈ alpha-olefins, e.g. propylene, which are grafted 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, e.g. an alkylene polyamine such as diethylene triamine, to form carboxyl-grafted polymeric imide derivatives are subsequently reacted with an anhydride of a C₁-C₃₀ hydrocarbyl-substituted acid, preferably acetic anhydride, to yield an oil-soluble stable amide of said polyamine. The oil solutions of said amide derivative are characterized by minimal viscosity change over an extended period of time.