Asymmetric triblock copolymer viscosity index improver for oil compositions

摘要

The present invention includes asymmetric triblock copolymers which are used as viscosity index improvers in oil compositions formulated for high performance engines. The triblock copolymers have the block structure hydrogenated polyisoprene-polystyrene-hydrogenated polyisoprene wherein the ratio of the number average molecular weights of the first and second hydrogenated polyisoprene blocks is at least 4.