METHOD OF OBTAINING A COPOLYMER IMPROVING VISCOSITY INDEX OF OIL, LUBRICATING OIL VISCOSITY INDEX IMPROVING ADDITIVE, LUBRICATING OIL MIXTURE AND COPOLYMER IMPROVING VISCOSITY INDEX OF OIL

摘要

There is provided a method for making a viscosity index improving copolymer which comprises polymerizing (meth)acrylate monomers and styrenic monomer(s) in an oil soluble diluent to form a solution of the copolymer in the oil soluble diluent, and wherein the solution includes less than or equal to 1000 parts by weight residual styrene monomer(s) per one million parts by weight solution.