One purpose of the present invention is to provide a water-absorbent resin having excellent water absorption characteristics and being capable of improving the shape-retaining characteristics of a water-absorbent material when used in the water-absorbent material. A water-absorbent resin obtained by performing reversed phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a hydrocarbon dispersion medium, using a radical polymerization initiator, said resin being capable of having both excellent absorption performance and shape retention in a water-absorbent material using the water-absorbent resin, as a result of fulfilling the conditions of: (1) having a water-retention capacity of physiological saline of at least 38 g/g (2) having a water-absorption capacity of physiological saline under a load of 4.14 kPa of at least 15 ml/g and (3) having a tan´ of a 50-fold swollen gel of at least 2.10 × 10 -2 .本發明目的之一在於提供一種吸水性能優良、且用於吸收體時可提高吸收體的形狀保持性之吸水性樹脂。一種吸水性樹脂,係令水溶性乙烯性不飽和單體在烴分散媒中,使用自由基聚合反應起始劑進行反相懸浮聚合所得者,且滿足(1)生理食鹽水保水力為38g/g以上;(2)在4.14kPa負荷下之生理食鹽水吸水力為15mL/g以上;(3)50倍澎潤時膠體之tanδ為2.10×10-2以上等三特性,藉此,對於經使用吸水性樹脂之吸收體而言,可兼具優良的吸收性能及形狀保持性。
