LUBRICATING OIL COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain a lubricating oil composition having excellent antioxidant performance by mixing a base oil comprising a mineral or synthetic oil having specified properties with an alkyl sulfide, an alkylated phenyl-α-naphthylamine and benzotriazole or its derivative. SOLUTION: A base oil comprising a mineral or synthetic oil and having a content of an aromatic component of 1mass% or below, a sulfur content of 100ppm or below and a viscosity index of 100 or above is mixed with 0.1-3mass% alkyl sulfide (e.g. di-n-butyl sulfide) represented by the formula: R<1> -S-R<2> (wherein R<1> and R<2> are each a 3-16 C hydrocarbon group), 0.1-3mass% alkylated phenyl-α-naphthylamine represented by formula I (wherein R<3> is a 1-16C alkyl) and 0.001-0.5 mass % benzotriazole represented by formula II or a derivative thereof and optionally 0.1-2mass% alkylated diphenylamine represented by formula III (wherein R<4> and R<5> are each H or a 1-16C alkyl), 0.1-1mass% phosphite represented by formula IV (wherein R<6> and R<7> are each a 1-12C alkyl) and about 0.01-5mass% alkylsuccinic acid derivative to obtain a lubricating oil composition.