HYDRAULIC DEVICE OPERATING OIL AND HYDRAULIC DEVICE USING SAID HYDRAULIC DEVICE OPERATING OIL

摘要

Provided is a hydraulic device operating oil which contains: a base oil; at least either a phosphorous acid ester compound or a phosphoric acid ester compound; and a secondary amide compound represented by formula 1. R₁ and R₂ are both a saturated or unsaturated alkyl group containing 8 to 24 carbon atoms.