文件类型：PDF文档
文件大小：267K
PROBLEM TO BE SOLVED : To provide a viscosity index improver which is highly fuel-efficient and hardly increases low-temperature viscosity of a lubricant composition.SOLUTION : The viscosity index improver contains a (co)polymer (A) comprising a monomer (a) represented by the general formula (1) as an essential constituent monomer. [Ris a hydrogen atom or a methyl group; Ris a C2-C4 alkylene group; Rand Rare each independently a hydrogen atom or a C1-C36 alkyl group, where the total number of carbon atoms in Rand Ris 3 or more; Ris a hydrogen atom or a C1-C16 alkyl group; Rand Rare each independently a hydrogen atom or a C8-C36 alkyl group, where the total number of carbon atoms in Rand Ris 8 or more; and X, X, and Xare each independently a group represented by -O-, -NH- or -S-.]