Ethylene-base copolymers, process for producing the same and lubricating oil compositions containing the same

摘要

There are disclosed an ethylenic copolymer comprising ethylene and an alpha-olefin in which diad chain distribution [EA] of ethylene [E] and alpha-olefin [A] as determined by the nuclear magnetic resonance spectrum method (13C-NMR method) and ethylene content a (mol %) as determined by nuclear magnetic resonance spectrum satisfy the following relational expressions (1) and (2): 0.7-2.8(0.5-alpha/100)2-|0.25(0.5-alpha/100)|<=[EA]<=2alpha/100 (1) (| | represents the absolute value) 10<=alpha<=90 (2) and in which the alpha-olefin has 3 to 20 carbon atoms; a process for producing the ethylenic copolymer and a lubricating oil composition comprising the same. Specifically the present invention provides the ethylenic copolymer which is imparted simultaneously with a high viscosity index and low pour point and accordingly, and is usable as a useful lubricating oil composition, when used alone as base oil for a lubricating oil, or as a viscosity index improver for another base oil; the process for producing the ethylenic copolymer; and the lubricating oil composition comprising the same.