MINERAL OIL-BASED BASE OIL, LUBRICATING OIL COMPOSITION, EQUIPMENT, LUBRICATING METHOD, AND GREASE COMPOSITION

摘要

The present invention provides a mineral base oil having a kinetic viscosity at 100° C. of 7 mm²/s or more and less than 10 mm²/s, a viscosity index of 100 or more, and a temperature gradient Δ|η*| complex viscosity between two temperature points of −5° C. and −15° C. of 240 mPa·s/° C. or less as measured with a rotary rheometer at an angular velocity of 6.3 rad/s. The use of the mineral base oil enables easy preparation of a lubricating oil composition and a grease composition having excellent oxidation stability while ensuring the freedom of selection of additives.