| abstract |
(57) [Summary] [Structure] Ethylene, α-olefin having 3 to 20 carbon atoms, alkyl (meth) acrylate, (meth) acrylalkylamide, alkylmaleate, alkylmaleamide, alkylmaleimide, Maleic anhydride, A viscosity index improver comprising a random copolymer containing one or more compounds selected from the group consisting of alkyl fumarate and alkyl fumaramide. [Effect] It has excellent ability to improve viscosity index and low temperature viscosity characteristics, as well as excellent thickening and oxidation resistance. |