Lubricant base oil, lubricant composition for internal combustion engine and lubricant composition for driving force transmitting device

摘要

The lubricating base oil of the invention is characterized by satisfying at least one of the following conditions (a) or (b). (a) A saturated compound content of 95% by mass or greater, and a proportion of 0.1-10% by mass of cyclic saturated compounds among the saturated compounds. (b) The condition represented by the following formula (1). 1.435n20-0.002xkv100 wherein n20 represents the refractive index of the lubricating base oil at 20° C., and kv100 represents the kinematic viscosity (mm2/s) of the lubricating base oil at 100° C.