| 摘要 |
PURPOSE:To obtain a hydrophilic foam persistently endowed with excellent hydrophilicity, water absorptivity and water retentivity, by heating and expanding an expandable crosslinking resin composition containing a PVA polymer. CONSTITUTION:A polyvinyl alcohol polymer-containing expandable crosslinking kneaded resin composition is heated and expanded. The obtained foam is acetalized to obtain the purpose hydrophilic foam. Although this foam may be used as a product after it is washed merely with water, it can be improved markedly in water return, water absorptivity, etc., when the foam after washing with water is further treated by contact with an aqueous alkali solution. Examples of the PVA polymers used include PVA having a degree of polymerization of about 500-2,000 and a degree of saponification >=90mol% and a saponificate of a copolymer of vinyl acetate with an unsaturated carboxylic acid or its derivative.
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