| abstract |
(57) [Summary] (Correction) [Solution] The amount of volatilization when heated in a thermostat at 180 ° C. for 500 hours is 35% by weight or less, and the pour point is −2. 0 ° C. or less, and the kinematic viscosity at 40 ° C. is 20-100. A grease base oil consisting of an ester of pentaerythritol and a carboxylic acid having a mm 2 / sec. [Effect] These grease base oils have excellent lubricity at low temperatures and can maintain excellent lubricity even when used for a long time at high temperatures. Exhibits excellent lubricity over a long period of time. |