Hydraulic working oil composition for buffers

摘要

A hydraulic working oil composition for buffers which comprises: a lubricating oil as a base oil, [I] at least one phosphorus-containing compound selected from the group consisting of a phosphoric acid having a specific structure and a phosphorous acid ester having a specific structure, and [II] at least one nitrogen-containing compound selected from the group consisting of an alkyleneoxide adduct of an aliphatic monoamine having a specific structure, an aliphatic polyamine having a specific structure and a salt of the above aliphatic polyamine having a specific structure, and [III] an aliphatic monoamine having a specific structure, the components [I] to [III] being essential components added to said base oil in a predetermined ratio; and a process for lubricating buffers with said hydraulic working oil composition.