Patent ID: 8722598

Claim:
A grease composition comprising; (A) a lithium soap thickener, (B) as a sole base oil, an ester type synthetic oil obtainable from trimethylolpropane and a mixture of a straight-chain saturated fatty acid having 6 to 12 carbon atoms and a branched saturated fatty acid having 16 to 18 carbon atoms, and (C) (c-1) a 1-naphthylamine type antioxidant represented by formula (I): wherein R 1 is a hydrogen atom and R 2 is a straight-chain or branched alkyl group having 1 to 12 carbon atoms, and (c-2) a diphenylamine type antioxidant, wherein the total content of (c-1) and (c-2) is in the range from 2.0 to 6.0 mass %, based on the total mass of the grease composition, and the ratio by mass of (c-1) to (c-2) is in the range from 30:70 to 70:30, wherein (c-2) the diphenylamine type antioxidant is a compound represented by formula (II): wherein R 3 and R 4 are each independently a hydrogen atom or a straight-chain or branched alkyl group having 1 to 12 carbon atoms.