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

摘要

The lubricating base oil of the invention has a kinematic viscosity at 40°C of 7 mm 2 /s or greater and less than 15 mm 2 /s, a viscosity index of 120 or greater, a urea adduct value of not greater than 4 % by mass, a BF viscosity at -35°C of not greater than 10,000 mP·s, a flash point of 200°C or higher and a NOACK evaporation loss of not greater than 50 % by mass. The method for producing a lubricating base oil of the invention comprises a step of hydrocracking/hydroisomerizing a feedstock oil containing normal paraffins so as to obtain a treated product having an urea adduct value of not greater than 4 % by mass, a kinematic viscosity at 40°C of 7 mm 2 /s or greater and less than 15 mm 2 /s, a viscosity index of 120 or greater, a BF viscosity at -35°C of not greater than 10,000 mP·s, a flash point of 200°C or higher and a NOACK evaporation loss of not greater than 50 % by mass. The lubricating oil composition of the invention comprises the lubricating base oil of the invention.