Patent ID: 6764985
Filing Date: 2004-07-20
Classification: C08F,C10M,C10N

Abstract:
A viscosity modifier for lubricating oil comprising an ethylene/&agr;-olefin copolymer (B) composed of:(i) ethylene, (ii) an &agr;-olefin of 3 or more carbon atoms, and (iii) a higher &agr;-olefin of 4 to 20 carbon atoms wherein the carbon number of (iii) is larger than that of (ii) by one or more, and the ethylene/&agr;-olefin copolymer (B) has the following properties (b-1) and (b-2): (b-1) a content of ethylene (i) is in the range of 60 to 80% by weight, a content of the &agr;-olefin of 3 or more carbon atoms (ii) is in the range of 15 to 39% by weight, and a content of the higher &agr;-olefin of 4 to 20 carbon atoms (iii) is in the range of 0.1 to 20% by weight with the proviso that the sum is 100% by weight; and (b-2) a weight-average molecular weight (Mw) in terms of polystyrene as measured by GPC is between 80,000 and 400,000; and (b-3) the ethylene/&agr;-olefin copolymer (B) has an intensity ratio D of S&agr;&bgr; to S&agr;&agr; (S&agr;&bgr;/S&agr;&agr;) determined by a 13C-NMR spectrum of 0.5 or below.