| abstract |
A lithium grease composition which can be sealed in a small motor bearing to reduce noise, composed of 5-20 % by weight of a thickener and 95-80 % by weight of a base oil, wherein said grease composition adopts lithium soap as the thickener, which is synthesized from lithium hydroxide and a higher fatty acid with 10 to 20 carbon atoms and/or a higher hydroxyfatty acid with one or more hydroxyl groups and 10 or more carbon atoms, and the base oil includes, as a main component, a polymer ester oil (A) in which 8 or more ester groups are arranged in a comb tooth form on one side of chain molecules constituted by eight or more carbon atoms which is expressed by general formula 1: (In the formula, each of R1, R2, R3 and R4 is an alkyl group, where x is an integer and x ≥ 2, and y is an integer and y ≥ 2.) and the base oil (40C) has a viscosity of 25 to 80mm2/s. |