Patent ID: 7135441

Claim:
A grease composition comprising a base oil having blended therewith a metallic soap-base thickener, wherein the base oil comprises a mixture of polar group- containing lubricating oil and non-polar lubricating oil, the metallic soap-based thickener contains a long-fibrous metrallic soap having a major axis part length of from 3 to 10 μm, in the content of 30 % by mass or more based on the total amount of the metallic soap-based thickener, the base oil contains a low-viscosity polar group-containing lubricating oil having a kinematic viscosity at 40° C. of 10 mm 2 /s to less than 150 mm 2 /s, a medium-viscosity polar group-containing lubricating oil having a kinematic viscosity at 40° of 150 mm 2 /s to less than 2,000 mm 2 /s and a high-viscosity viscosity polar group-containing lubricating oil having a kinematic viscosity at 40° of 2,000 mm 2 /s to 1000,000 mm 2 /s, the base oil contains the high-viscosity polar group viscosity polar group-containing lubricating oil in the content of 5 to 30 % by mass based on the total amount of the base, and the base oil and base oil contains the polar group-containing lubricating oil, including the low-viscosity, meduium-viscosity and high-viscosity polar group-containing lubricating oils, in the content of not more than 70 % by mass based on the total amount of the base oil.