This invention provides a method for producing a water-absorbent resin and the water-absorbent resin made by this method. The water-absorbent resin made by this method has less odd smell in the raw material, particularly the odd smell originated from petro-hydrocarbon dispersion medium than a water-absorbent resin available from conventional techniques. In particular, the present invention provides a method for producing a water-absorbent resin by reverse phase suspension polymerizing a water-soluble ethylenic non saturated monomer in a petro-hydrocarbon ispersion medium, the method comprising: (A) adding an aqueous solution of a water-soluble ethylenic non saturated monomer, which contains a hydrophilic dispersion, in a eptro-hydrocarbon clispersion medium in which a hydrophobic polymeric dispersion agent is dispersed with heat or dispersed with heat the solution is agitated and the hydrophilic polymeric dispersion agent is primary dispersed, in the absence of a surfactunt, (B) adding a surfactant in the dispersed liquid, which is obtained in a primary dispersion, to perform a secondary dispersion, and (C) performing a reverse phase suspension polymerization of the recondary disperred liquid by using a radical polymerizing initiator.本申請案係提供吸水性樹脂的製造方法及藉由該方法所得之吸水性樹脂,更詳細而言,藉由逆相懸浮聚合法製造吸水性樹脂之方法,其中原料成分,尤其是源自石油系烴分散媒之臭味與藉由以往技術所得之吸水性樹脂相比較,進一步減少之吸水性樹脂的製造方法及藉由該方法所得之吸水性樹脂。更詳細而言,本申請案係提供吸水性樹脂的製造方法及藉由該方法所得之吸水性樹脂,該製造方法係將水溶性烯性不飽和單體於石油系烴分散媒中進行逆相懸浮聚合而製造吸水性樹脂之方法,其特徵為含有下述步驟:(A)在界面活性劑不存在下,將含有親水性高分子系分散劑之水溶性烯不飽和單體水溶液在攪拌下添加於疏水性高分子系分散劑經加熱分散或加熱溶解之石油系烴分散媒中,進行一次分散、(B)於一次分散後所得到之分散液中添加界面活性劑,進一步進行二次分散,然後(C)使用自由基聚合起始劑進行逆相懸浮聚合。
