METHOD FOR PRODUCING WATER ABSORBENT POLYACRYLIC ACID (SALT) RESIN POWDER, AND WATER ABSORBENT POLYACRYLIC ACID (SALT) RESIN POWDER

摘要

Disclosed is a method for producing a water absorbent resin powder that is improved in liquid permeability (SFC), while maintaining appropriate water absorption rate (FSR). Specifically disclosed is a method for producing a water absorbent polyacrylic acid (salt) resin powder, which comprises: a polymerization step of an aqueous solution of an acrylic acid (salt) monomer; a gel grinding step of a hydrous gel-like crosslinked polymer during the polymerization or after the polymerization; and a drying step after the gel grinding. In the gel grinding step, a hydrous gel-like crosslinked polymer having a resin solid content of 10-80% by weight is subjected to gel grinding with a gel grinding energy (GGE) of 18-60 (J/g), and following that the resulting is dried at a drying temperature of 150-250°C and then subjected to a surface treatment.