Polymer composition viscosity index improver additive and lubricating oil containing the additive

摘要

A viscosity index improver additive composition contains, as one component, a vinyl aromatic/conjugated diene polymer of specific structure and composition and, as a second component an ethylene/C3 to C18 alpha olefin copolymer of specific composition and viscosity. Preferably the composition also contains a polybutene of defined molecular weight.