| 摘要 |
PROBLEM TO BE SOLVED: To provide a defoaming agent which is safe and excellent in dispersibility to water and superior in foam breaking effect and defoaming effect with respect to a water soluble polymer, especially PVA and partially saponified PVA. SOLUTION: This defoaming agent contains a compound expressed by the formula; HO-(BO)l-(AO)m-(BO)n-H. In the formula, AO is a 2-3C oxyalkylene group containing >=20 wt.% oxyethylene group, BO is an oxybutylene group, m=8-210, and l+n=4-20.
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