| 摘要 |
PURPOSE:To improve high-temp. and low-temp. performance, durability and pump efficiency, by preparing the title composition which comprises a 14-26C alpha-olefin oligomer, a petroleum lubricating oil fraction and a particular viscosity index improver. CONSTITUTION:75-85wt.% 14-26C alpha-olefin oligomer (A) (e.g., a dimer of 1-decene) is mixed with 12-20wt.% petroleum lubricating oil fraction (B) having a viscosity (100 deg.C) of 3.5-5.5cst, a viscosity index of 100 or more and a fluid point of -10 deg.C or below, 3-5wt.% viscosity index improver (C) composed of an ethylene-alpha-olefin copolymer having a number-average MW of 26000-40000, 0.1-10wt.% optional additive (D) composed of 0.1-3wt.% antioxidant, 0.1-5wt.% abrasion preventive, 0.5-6wt.% oiliness improver, 0.1-4wt.% detergent-dispersant and 0.002-0.5wt.% deforming agent, thereby preparing an automatic transmission oil compsn. having a viscosity of 6cst or more at 140 deg.C, a viscosity of 2400cp or less at -30 deg.C, a shear stability of 20% or less in terms of percentage lowering in viscosity at 100 deg.C and a flash point of 155 deg.C or above. |
