POLY(METH)ACRYLATE-BASED VISCOSITY INDEX IMPROVER, LUBRICANT ADDITIVE AND LUBRICANT COMPOSITION CONTAINING VISCOSITY INDEX IMPROVER

摘要

The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a core portion and three or more arm portions, wherein each of the arm portions consists of a polymer chain comprising a structural unit represented by the following formula (1), and one end of the polymer chain is bonded to the core portion, and wherein a weight-average molecular weight Mw is 100000 or more, and a ratio of the weight-average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.6 or less. [R 1 represents hydrogen or a methyl group, and R 2 represents a C1 to C36 alkyl group.]