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AssigneeSumitomo Seika Chemicals Co., Ltd.
InventorsShinya Fukudome, Junichi Takatori, Kenya Matsuda, Yasuhiro Nawata
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Process for preparing a water-absorbent resin comprising carrying out a reversed-phase suspension polymerization in multi-steps of two or more steps. The water-absorbent resin is prepared by subjecting a water-soluble ethylenically unsaturated monomer to the reversed phase suspension polymerization. This process for preparing a water-absorbent resin involves adding an aminocarboxylic acid compound to at least one step in the second and subsequent steps to carry out the polymerization reaction. The resulting water-absorbent resin can be suitably used in a hygienic material. The water-absorbent resin has a high degree of water-retention, including a high degree of water absorption under pressure. It also has a high water absorption rate, and contains only a small amount of water-soluble substances.
A process for preparing a water-absorbent resin having a water-retention capacity of 0.9% by weight physiological saline of 40 g/g or more and a water absorption capacity of 0.9% by weight physiological saline under a pressure of a 4.14 kPa load of 15 ml/g or more, said process comprising
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