VISCOSITY INDEX IMPROVER FOR LUBRICANT

摘要

PURPOSE:The titled improved having improved cleaning and dispersing action and heat stability, comprising a compound obtained by radically polymerizing a nitrogen-containing monomer in the presence of a copolymer of a higher and a lower alkyl(meth)acrylates/styrene as an essential component. CONSTITUTION:(D) A viscosity index improver for lubricating oil comprising a compound obtained by radically polymerizing 2-10pts.wt. monomer containing nitrogen in the molecule polymerized in the presence of a copolymer consisting of (A) 50-95pts.wt. 8-20C higher alkyl (meth)acrylate, (B) 0-20pts.wt. 1-4C lower alkyl (meth)acrylate and (C) 3-20pts.wt. styrene as an essential component. N-Vinyl-2-pyrrolidone may be cited as the preferably example of the component D.