| abstract |
This invention aims to provide lubricating oilncompositions excellent in low-temperature properties,noxidation stability, lubricity at high temperatures and fuelnefficiency and also in handling properties at low temperatures,nand a viscosity modifier for lubricating oil employable in saidnlubricating oil compositions. n The viscosity modifier for lubricating oil comprises annethylene/α-olefin copolymer (B) composed of:n (i) ethylene, (ii) an α-olefin of 3 or more carbon atoms, and (iii) a higher α-olefin of 4 to 20 carbon atoms whereinnthe carbon number of (iii) is larger than that of (ii) by onenor more, and n the ethylene/α-olefin copolymer (B) has the followingnproperties (b-1) and (b-2):n (b-1) a content of ethylene (i) is in the range of 40 ton80 % by weight, a content of the α-olefin of 3 or more carbonnatoms (ii) is in the range of 15 to 59 % by weight, and a contentnof the higher α-olefin of 4 to 20 carbon atoms (iii) is in thenrange of 0.1 to 25 % by weight with the proviso that the sumnis 100 % by weight; and (b-2) a weight-average molecular weight (Mw) in terms ofnpolystyrene as measured by GPC is between 80,000 and 400,000. |