| 摘要 |
PROBLEM TO BE SOLVED: To provide a grease composition which is excellent in heat resistance and low-temperature properties and has a long lubrication life by using, as the base oil, a synthetic ester oil which is prepared by reacting a tri- or tetrahydric alcohol with a carboxylic acid mixture and has specified pour point and kinematic viscosity. SOLUTION: A tri- or tetrahydric alcohol is reacted with a carboxylic acid mixture comprising 0.5-20 mol% 16C or 18C branched saturated fatty acid, 50-96.5 mol% n-heptanoic acid, and 3-40 mol% at least one branched saturated fatty acid selected from among isoheptanoic, 2-ethylhexanoic, and isononanoic acids in an equivalent ratio of carboxyl groups of the acid mixture to hydroxyl groups of the alcohol of 1.0-1.3, thus giving a synthetic ester oil having a pour point of -40 deg.C or lower, a kinematic viscosity of 10-100 mm2/sec, an acid value of 1.0 mgKOH/g, and a hydroxyl value of 10.0 mgKOH/g, which is used as a base oil. This base oil is compounded with at least one thickener selected from among metal soaps, urea compounds, urethane compounds, bentonite, and silica. |
