摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic-actuating oil composition usable over a long period of time by effectively preventing early-stage deterioration and sludge formation of a hydraulic oil caused by high pressurization. SOLUTION: The hydraulic-actuating oil composition is obtained by formulating (A) 0.01-5 wt.% of an amine-based antioxidant such as 4,4'-dioctyldiphenylamine, (B) 0.01-5 wt.% of a phenolic antioxidant such as 2,6-di-tert-butyl-4-methylphenol and (C) 0.01-5 wt.% of a phosphate such as tricresyl phosphate to a base oil having %CA of at most 5, on the basis of the total amount of the composition. COPYRIGHT: (C)2008,JPO&INPIT |