| abstract |
The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a polymer chain comprising a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), wherein Mw is 100000 or more, and Mw/Mn, is 1.6 or less. n n n n n n n n n n n n [R 1 represents hydrogen or a methyl group, and R 2 represents a group represented by the following formula (3), and R 3 represents a C1 to C18 alkyl group that is straight-chain or has a branch having 5 or less carbon atoms. n n n n n n n n n n n n n n n n m and n are integers which satisfy m≧5, n≧4, and m+n≦31.] |