| abstract |
Substantially or fully hydrogenated (C6 or lower) diolefin-lower (C1-C8) alkyl acrylate or methacrylate copolymers can be used as additives to improve the viscosity index (VI) of lubricating oils. The preferred copolymer is a fully hydrogenated, high molecular weight copolymer of 1,3-butadiene and methyl methacrylate containing at least 71 mole percent 1,3-butadiene. A pour point depressant, VI improving polymer additive for lubricating oils is provided by incorporating a higher (C12-C20) alkyl methacrylate in the copolymer. A dispersant VI improving copolymer for lubricating oils and a dispersant for hydrocarbon fuels may be prepared by graft polymerizing a polar, nitrogen-containing graft monomer onto these copolymers. |