LUBRICANT BASE OIL, METHOD FOR PRODUCTION THEREOF, AND LUBRICANT OIL COMPOSITION

摘要

Disclosed is a lubricant base oil which has a urea adduct fraction of 4 mass% or less, a kinematic viscosity of 25 to 50 mm2/s at 40°C, a viscosity index of 140 or greater, a CCS viscosity of 15,000 mPa · s or less at -35°C, and a flash point of 250°C or higher. Also disclosed is a method for producing a lubricant base oil, which comprises the step of carrying out the hydrogenation-and-decomposition/hydrogenation-and- isomerization of a raw oil comprising normal paraffin so that a product of the above-mentioned treatment can have a urea adduct fraction of 4 mass% or less, a kinematic viscosity of 25 to 50 mm2/s at 40°C, a viscosity index of 140 or greater, a CCS viscosity of 15,000 mPa · s or less at -35°C, and a flash point of 250°C or higher. Further disclosed is a lubricant oil composition comprising the lubricant base oil.