| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a viscosity index improving agent which has a high viscosity index improving effect. <P>SOLUTION: The viscosity index improver contains a (co)polymer (A) including a monomer (a) having a silicon atom as an essential constituting monomer and also has a solubility parameter of 7.0 to 8.0, and the monomer (a) is preferably the one represented by general formula (1) (wherein, Q denotes a 2 to 12C radical polymerizable alkenyl group or a (meth)acryloyloxy group; R<SP POS="POST">1</SP>denotes a 1 to 6C alkylene group; R<SP POS="POST">2</SP>to R<SP POS="POST">6</SP>denote a 1 to 12C alkyl group, independently respectively; and m denotes a number of 1 to 200). <P>COPYRIGHT: (C)2013,JPO&INPIT |
