VISCOSITY INDEX IMPROVER AND LUBRICATING OIL COMPOSITION CONTAINING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a viscosity index improver capable of preparing a lubricating oil composition having a high viscosity index, excellent low temperature fluidity and a low dielectric constant.SOLUTION: There is provided a viscosity index improver comprising a polymer (A) containing a (meth)acrylate (a) having a hydroxycycloalkyl group as an essential constitutional monomer, in which more preferably, the polymer (A) contains an alkyl(meth)acrylate (b1) having an alkyl group having 1 to 4 carbon atoms and/or an alkyl(meth)acrylate (b2) having an alkyl group having 8 to 24 carbon atoms as an essential constitutional monomer.