| 摘要 |
PROBLEM TO BE SOLVED: To obtain a grease composition which can decrease frictional power even under low-speed and low-load conditions by compounding a base oil containing at least a specified amount of a synthetic ester oil with a thickening agent containing lithium soap fibers having a specified length or longer. SOLUTION: This composition contains a base oil which contains at least 50 wt.% synthetic ester oil (e.g. a pentaerythritol ester) and has a kinematic viscosity (at 40 deg.C) of 5-400 mm2/s and a thickening agent which contains lithium soap (e.g. lithium hydroxystearate) fibers having lengths of 3.0μm, preferably in an amount of 2-50 wt.% of the composition, The composition is prepared e.g. by adding a lithium soap to a base oil containing a synthetic ester oil, heating the base oil to 235 deg.C to dissolve the soap in the oil, slowly cooling the resultant solution to room temperature to form a short-fiber soap having a length of 1-2μm and keeping the soap at a temperature (180-190 deg.C) not completely redissolving the soap under stirring to cause the fiber length to grow. |
