POLY (METH) ACRYLIC ACID (SALT) PARTICULATE WATER

[Problem] To provide a paper diaper in which the amount of reflux is reduced regardless of the concentration and configuration of a water absorbent in an absorber, and which has an excellent liquid absorption rate. [Solution] The absorption rate and surface tension of a water absorbent are adjusted to specific ranges, and a water-containing gel-like crosslinked polymer obtained by a polymerization step is pulverized to a specific weight-average particle diameter, dried, and then added with a liquid permeability improving agent during or after surface crosslinking, thereby obtaining the water absorbent. Thus, a water absorbent having excellent GCA (Gel Capillary Absorption) and FGBP (Free Gel Bed Permeability) can be obtained. 【课题】提供无论吸收体中的吸水剂浓度、构成如何均减少回流量、具有优异的液体吸收速度的纸尿布。【解决手段】将吸水剂的吸收倍率、表面张力调整为特定的范围，并且将通过聚合工序得到的含水凝胶状交联聚合物粉碎至特定的重均粒径，干燥后，在表面交联中或表面交联后添加透液改善剂，从而能够得到GCA(凝胶毛细管吸收)和FGBP(自由凝胶床透过性)优异的吸水剂。