Abstract: The invention provides a compressor oil, wherein 2,6-di-tert-butylphenol and tris (2,4-di-tert-butylphenyl) phosphite are added to a base oil having a naphthene content of from 17 to 30% based on the total amount of the base oil, and has a pour point of ?25° C. or lower. 2,6-di-tert-butylphenol is effective when it is contained in an amount of from 0.5 mass % to 6.0 mass % based on the total amount of the compressor oil, and tris (2,4-di-tert-butylphenyl) phosphite is effective when it is contained in an amount of from 0.3 mass % to 2.0 mass % based on the total amount of the compressor oil. Furthermore, adding an alkaline earth metal salt of alkylsalicylic acid in combination is even more effective. The amount thereof used is preferably from 0.05 mass % to 2.0 mass %.

Abstract: The invention provides a compressor oil, wherein 2,6-di-tert-butylphenol and tris (2,4-di-tert-butylphenyl) phosphite are added to a base oil having a naphthene content of from 17 to 30% based on the total amount of the base oil, and has a pour point of ?25° C. or lower. 2,6-di-tert-butylphenol is effective when it is contained in an amount of from 0.5 mass % to 6.0 mass % based on the total amount of the compressor oil, and tris (2,4-di-tert-butylphenyl) phosphite is effective when it is contained in an amount of from 0.3 mass % to 2.0 mass % based on the total amount of the compressor oil. Furthermore, adding an alkaline earth metal salt of alkylsalicylic acid in combination is even more effective. The amount thereof used is preferably from 0.05 mass % to 2.0 mass %.

Abstract: An object of the present invention is to provide a lubricating oil composition for hydraulic actuation which has excellent safety and which is imparted with electrical conductivity in order to prevent the generation of noise that adversely affects devices including hydraulic circuits equipped with an electronic control device for the valve system. The composition uses a hydrocarbon base oil, and the base oil contains from 30 to 250 ppm of ultrabasic magnesium salicylate in terms of magnesium content relative to the total amount of the composition, and from 0.07 to 5.0 mass % of non-dispersible polymethacrylate having a weight-average molecular weight of from 5,000 to 200,000 as a net amount relative to the total amount of the composition. The conductivity of the composition at 25° C. is 200 pS/m or more, the flash point is 240° C. or more, the pour point is negative 40° C. or less, and the coefficient of friction at 140° C. by a microclutch is 0.08 or more.

Abstract: An object of the present invention is to provide a lubricating oil composition for hydraulic actuation which has excellent safety and which is imparted with electrical conductivity in order to prevent the generation of noise that adversely affects devices including hydraulic circuits equipped with an electronic control device for the valve system. The composition uses a hydrocarbon base oil, and the base oil contains from 30 to 250 ppm of ultrabasic magnesium salicylate in terms of magnesium content relative to the total amount of the composition, and from 0.07 to 5.0 mass % of non-dispersible polymethacrylate having a weight-average molecular weight of from 5,000 to 200,000 as a net amount relative to the total amount of the composition. The conductivity of the composition at 25° C. is 200 pS/m or more, the flash point is 240° C. or more, the pour point is negative 40° C. or less, and the coefficient of friction at 140° C. by a microclutch is 0.08 or more.