| 摘要 |
PROBLEM TO BE SOLVED: To provide a lubricant composition suppressing generation of precipitate, increase of kinematic viscosity and volatility in using at a high- temperature, having high viscosity index and excellent low-temperature fluidity by mixing an additive such as an antioxidant with a specific ester-based lubricating oil. SOLUTION: This lubricant composition is a mixture of (A) a polyol ester- based lubricating oil synthesized from tripentaerythritol with an aliphatic acid mixture (preferably containing 60-90wt.% of 5C, 7C and 9C branched and saturated aliphatic acids) with an additive package containing at least one kind of (B) an antioxidant, (C) a wear-inhibiting agent (e.g. triglycidyl phosphate), (D) a foaming agent (e.g. polysiloxane) and (E) a metal-inactivating agent (e.g. benzotriazole). Preferably, a mixture of a phenolic antioxidant with an amine- based antioxidant is used as the component B. As the former, bis-2,6-di-tert- butylphenol, etc., is preferably used. Preferably, a mixture of an alkylated diphenylamine with an alkylated N-phenyl-1-naphthylamine is used as the latter. |
