| 摘要 |
PROBLEM TO BE SOLVED: To provide a water-containing hydraulic fluid having small pH decrease, excellent in oxidation stability with small pH decrease by inhibiting acid formation over long time use.SOLUTION: A water-containing hydraulic fluid contains 0.01 to 1 mass% of one or more kind selected from compounds represented by general formulae (1) and (2). The general formula (1): a compound in which each two nitrogen atoms in piperazine is substituted by Rand R, where Rand Rare hydrogen atoms or alkyl groups having 1 to 3 carbon atoms, and at least one of Rand Ris an alkyl group having 1 to 3 carbon atoms. The general formula (2): a compound in which a nitrogen atom in piperidine is substituted by R, where Ris a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. |
