| 摘要 |
PURPOSE:To provide a water/glycol-based hydraulic liquid containing a specific water-soluble polyurethane resin, having a viscosity adjustable to a proper level by the addition of a small amount of the resin, exhibiting excellent lubricity, metal-abrasion resistance and durability and useful for a vane pump of a hydraulic apparatus, etc. CONSTITUTION:This water/glycol-based hydraulic liquid contains water, glycol and preferably 5-20wt.% of a water-soluble polyurethane resin (having an NHCOO concentration of preferably 0.1-5wt.%) having a weight-average molecular weight of 5,000-300,000 and an oxyethylene unit content of >=260wt.% and derived from (A) a water-soluble polyoxyalkylene polyol such as an ethylene oxide homopolymer and/or a random or block copolymer of ethylene oxide and propylene oxide and (B) an organic polyisocyanate such as 4,4'- diphenylmethane diisocyanate. |
