| 摘要 |
PROBLEM TO BE SOLVED: To provide a viscosity index improver capable of imparting a sufficient friction loss reducing effect to a lubricating oil and to provide a lubricating oil additive and a lubricating oil composition containing the viscosity index improver.SOLUTION: There is provided a poly(meth)acrylate-based viscosity index improver having a polymer chain containing a structural unit represented by the following general formula (1), where the weight average molecular weight (Mw) of the poly(meth)acrylate-based viscosity index improver is less than 100000 and the ratio (Mw/Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is 1.6 or less. [where, Rrepresents a hydrogen atom or a methyl group; and Rrepresents an alkyl group having 1 to 36 carbon atoms.] |
