Antifoaming agent, water-soluble resin composition containing the same, aqueous solution of water-soluble resin

摘要

PROBLEM TO BE SOLVED: To provide a defoaming agent excellent in defoaming property, capable of showing excellent defoaming property, especially regardless of a service temperature.SOLUTION: A defoaming agent to be used contains a nonionic surfactant (A) whose cloud point in 1 wt% ion-exchange aqueous solution is 10-50°C and a nonionic surfactant (B) whose cloud point in 1 wt% ion-exchange aqueous solution is 0°C or lower which is out of a measurement limit, and further, preferably contains at least one kind of a nucleus agent (C) selected from a group comprising hydrophobic silica (Ca), fatty amide (Cb) and wax (Cc)SELECTED DRAWING: None