BIODEGRADABLE GREASE COMPOSITION FOR AEROGENERATOR

摘要

An object of the present invention is to provide a biodegradable grease composition which is excellent in fretting resistance, extreme pressure property, low temperature property, and biodegradability as well, and has a small effect to the environment even if released to a natural environment. The grease composition comprises a base oil composed of an ester oil having a kinematic viscosity at 40°C of 60 to 160 mm 2 /s and a thickener composed of a diurea compound obtained by allowing an amine mixture comprising a 4-8C alicyclic monoamine and a 20-24C aliphatic monoamine to react with a diisocyanate compound, wherein a content molar ratio of the alicyclic monoamine and the aliphatic monoamine in the amine mixture is 7:3 to 9:1, the content of the thickener in a total amount of the base oil and the thickener is 7 to 11 % by mass and a penetration is 265 to 340.