| 摘要 |
PROBLEM TO BE SOLVED: To provide a powdery hydrophilic polymer obtained by drying a hydrophilic polymer comprising a water-in-oil emulsion, which has a relatively large particle diameter compared to a conventional dry powder process from a water-in-oil emulsion, whose particle diameter does not depend on drying conditions, and which enables easy setting of drying conditions; and to provide a method of producing the powdery hydrophilic polymer.SOLUTION: A powdery hydrophilic polymer is obtained by agglomerating hydrophilic polymer comprising a water-in-oil emulsion in a liquid state by an emulsion breaking process, then granulating the agglomerate, and drying it. A hydrophilic organic solvent is used as an emulsion breaker, and the solvent preferably has a boiling point of 50°C or higher and 200°C or lower. The powdery hydrophilic polymer can be prepared into a powder having an average particle diameter of 0.3 mm to 5 mm by performing grain refining after drying. Since the powder easily floats when the powder is charged into dissolution water and does not adhere to the wall surface of a dissolution tank, the powder is highly convenient for handling. |
