VISCOSITY INDEX IMPROVER AND LUBRICANT COMPOSITION

摘要

Disclosed is a viscosity index improver which is excellent in shear stability, viscosity index improvability and low-temperature viscosity characteristics. Also disclosed are a lubricant composition containing such a viscosity index improver, and a monomer which is used for producing such a viscosity index improver. Specifically disclosed is a viscosity index improver composed of a copolymer (A) which contains a monomer (a) represented by the general formula (1) below as a constituent monomer. Also specifically disclosed is a lubricant composition containing the viscosity index improver and a base oil, and a monomer composition containing the monomer (a).