| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lubricating oil composition excellent in wear resistance even when an ester having especially high polarity is used as a base oil by blending an ester as a base oil with a prescribed phosphorus compound and a specified benzotriazole derivative. SOLUTION: This lubricating oil composition comprises (A) a phosphorus compound selected from compounds of formula I, formula II or formula III (R<1> to R<5> and R<7> to R<9> are each a 6-8C aryl, a 1-18C straight-chain alkyl, etc., at least one of R<1> to R<3> , at least one of R<4> and R<5> and at least one of R<7> to R<9> are each a 6-18C aryl; R<6> is H, a 1-18C straight-chain alkyl, etc.) (preferably triphenyl phosphite, etc.), (B) a benzotriazole derivative of formula IV (R<10> is a 0-20C group containing a nitrogen atom and/or an oxygen atom; X is H or methyl) and (C) an ester as a base oil selected from a 2-10C dihydric to hexahydric saturated aliphatic polyhydric alcohol or an adduct of an alkylene oxide to the alcohol and a 5-24C straight-chain or branched chain aliphatic monocarboxylic acid or its derivative, animal and vegetable oils and fats and an animal and vegetable oil and fat derivative. |
