| abstract |
Provided is a lubricating oil composition that is difficult to separate from a base oil while improving low-temperature fluidity even when a viscosity index improver having a high effect of improving the viscosity index is used. A lubricating oil composition according to an embodiment of the present invention comprises an oxygen-containing synthetic base oil having an oxygen content (A) of 15 to 40% by mass and a kinematic viscosity at 100 ° C. of 0.5 to 50 mm 2 / s. And a viscosity index improver that is an oxygen-containing compound having an oxygen content (B) of 15 to 40% by mass and a kinematic viscosity at 100 ° C. of 11,000 mm 2 / s or more, the oxygen-containing synthetic base oil and the viscosity index The mass ratio of the improver is 99.5: 0.5 to 75:25, and the ratio of the oxygen content (A) of the oxygen-containing synthetic base oil to the oxygen content (B) of the viscosity index improver (A / B) is in the range of 0.5-2. [Selection figure] None |