| 摘要 |
The lubricating oil composition of the invention comprises a lubricating oil base (A) and a copolymer (B) of ethylene and an alpha -olefin of 3 to 20 carbon atoms. The copolymer (B) of ethylene and an alpha -olefin of 3 to 20 carbon atoms is contained in the composition in an amount of 1 to 20 % by weight and has the following properties: (1) the ethylene content (E) is in the range of 40 to 77 % by weight, (2) the weight-average molecular weight (Mw) in terms of polystyrene, as measured by GPC, is in the range of 80,000 to 400,000, (3) Mw/Mn is not more than 2.4, (4) the melting point (Tm), as measured by DSC, is not higher than 60 DEG C, (5) the ethylene content (E, % by weight) and the melting point (Tm, DEG C), as measured by DSC, satisfy the following relation (I): <DF NUM="(I),">3.31xE-186 ≥ Tm </DF> and (6) the proportion (V, %) of alpha beta carbon atoms to all carbon atoms in the main chain, and if present, the long-chain branches, and the ethylene content (E, % by weight) satisfy the following relation: <DF NUM="(II).">V ≤ 10-0.1xE </DF> |
