Patent ID: 6525007
Filing Date: 2003-02-25
Classification: C10M,C10N

Abstract:
A viscosity modifier for a lubricating oil, comprising an ethylene/propylene copolymer (A) having the following properties (a-1) to (a-5):(a-1) the density is in the range of 857 to 882 kg/m3, (a-2) the weight-average molecular weight as measured by gel permeation chromatography is in the range of 80,000 to 400,000 in terms of polystyrene, (a-3) Mw/Mn (Mw: weight-average molecular weight, Mn: number-average molecular weight), which is an indication of a molecular weight distribution, is not more than 2.3, (a-4) the melting point as measured by a differential scanning calorimeter is in the range of 15 to 60Â° C., and (a-5) the density (D (kg/m3)) and the melting point (Tm (Â° C.)) as measured by a differential scanning calorimeter satisfy the following relation (I) Tm&lE;1.247Ã—Dâˆ’1037â€ƒâ€ƒ(I).