Patent ID: 8497226
Filing Date: 2013-07-30
Classification: A61L,B01J,C08F,C08J

Abstract:
1. A water absorbent, comprising: water-absorbing resin particles, which are surface cross-linked and formed of a water-absorbing resin having a cross-linked structure prepared by polymerizing a monomer including 70 mol % to 100 mol % of an acrylic acid and a salt of the acrylic acid; and a liquid permeability improver (F), an additive amount of the liquid permeability improver (F) being 0.01 part by weight to 10 parts by weight with respect to 100 parts by weight of the water-absorbing resin particles, the liquid permeability improver (F) being selected from the group consisting of water-insoluble hydrophilic inorganic particles, water-soluble multivalent metal salt, a cationic polymer compound, and hydrophobic inorganic particles, the water absorbent satisfying the conditions that: (a) 90% to 100% by weight of the water-absorbing resin particles have a diameter ranging from 150 μm to 850 μm; (b) a logarithmic standard deviation (σζ) of a size distribution of the water-absorbing resin particles ranges from 0.25 to 0.45; (c) AAPs for 0.9 wt % saline is at least 20 g/g; (d) CRCs for 0.9 wt % saline ranges from 29 g/g to 39 g/g; and (e) a chemical cross-linking index is at least 160, the chemical cross-linking index represented by Formula (1): wherein CRCs (g/g) is an absorbency for 0.9 wt % saline, and CRCdw (g/g) is an absorbency for deionized water.