POLYACRYLIC ACID-BASED WATER-ABSORBING RESIN POWDER AND METHOD FOR PRODUCING THE SAME

摘要

Provided is a method for producing a polyacrylic acid-based water-absorbing resin powder comprising a step for obtaining an aqueous acrylic acid-based monomer solution in which a gas is dissolved and/or dispersed, a step for polymerizing the aqueous monomer solution in the absence of surfactant or the presence of 300 ppm of surfactant, a step for fragmentation of the resulting water-containing gel-like crosslinked polymer during polymerization or after polymerization, and a step for heating and drying the fragmented water-containing gel-like crosslinked polymer. The method for dissolving and/or dispersing a gas in the step for obtaining an aqueous acrylic acid-based monomer solution is at least one method selected from (a) a method involving increasing the pressure of the aqueous monomer solution and the gas, (b) a method involving forming a swirling flow of the aqueous monomer solution and the gas, and (c) a method involving mixing the aqueous monomer solution with the gas that has passed through fine pores. Thus, a water-absorbing resin having a fast water absorption rate can be produced with high efficiency without interfering with the liquid absorption properties for a hygiene product, and the like.