| 摘要 |
PURPOSE:To obtain a multigrade engine oil compsn. having excellent shear stability and cleaning properties, by mixing a mineral oil with an ethylene-alpha- olefin copolymer, a polymethacrylate and a cleaning agent or an antioxidant. CONSTITUTION:A compsn. is prepd. by mixing a mineral oil (A) having a dynamic viscosity at 100 deg.C of 1-50cSt and a viscosity index of at least 60 with an ethylene-alpha-olefin copolymer (B) having a number-average MW of 800-8,000 in an amt. of 0.5-20wt.% based on the whole of the compsn., 0.05-20wt.% polymethacrylate (C) having a number-average MW of 10,000-250,000 or a mixture thereof with an olefin copolymer and 1-20wt.% cleaning dispersant (D) and/or an antioxidant. Esp. pref. examples of component (D) include a mixture of dithiophosphoric acid, a sulfonate and/or a sulfinate and succinimide. |
