| 摘要 |
PURPOSE:To provide a quenching oil additive composed of a specific water-soluble polyurethane resin, capable of controlling the quenching speed by the addition of a small amount of the additive, effective for suppressing the generation of strain and cracking the quenching object and having low fire hazard risk, etc., and excellent handleability. CONSTITUTION:This quenching oil additive is composed of a water-soluble polyurethane resin (having NHCOO group concentration of preferably 0.1-5wt.%) having a weight-average molecular weight of 20,000-300,000 and an oxyethylene unit content of->=60wt.% and derived from (A) a water-soluble polyalkylene polyol having a number-average molecular weight of 3,000-35,000 such as random copolymer of ethylene oxide and propylene oxide and/or a random addition product of ethylene oxide/propylene oxide to a polyhydric alcohol and (B) one or more organic polyisocyanates selected from 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate. |
