| abstract |
The present invention relates to a lubricating oil composition comprising: n (A) a mineral oil having a kinematic viscosity at 100° C. of 1 to 50 centistokes and a viscosity index of at least 60, n (B) 0.5 to 20% by weight based on the total weight of the composition of an ethylene-α-olefin copolymer having a number average molecular weight of 800 (inclusive) to 5,000 (exclusive), n (C) 0.05 to 20% by weight based on the total weight of the composition of polymethacrylate having a number average molecular weight of 10,000 to 250,000 or a mixture of said polymethacrylate and an olefin copolymer, and n (D-I) 1 to 20% by weight based on the total weight of the composition of a detergent-dispersant and/or an antioxidant, or n (D-II) 0.5 to 20% by weight based on the total weight of the composition of at least one member selected from the group consisting of a extreme pressure agent, an anti-wear agent and an oiliness agent. n According to the present invention, a multi grade lubricating oil composition which is excellent in shear stability can be obtained. |