Polyacrylic acid (salt)-based water-absorbent resin and method for producing same

Abstract

In order to realize, while preventing gelatification of a monomer not yet to be polymerized, a water-absorbent resin which is more stable in color over time and has a significant enhancement in a problem concerning surface color and an excellent absorption property, a method for producing a polyacrylic acid-based water-absorbent resin includes: a preparation step in which a monomer is prepared from acrylic acid including hydroxyacetone in an amount not larger than 300 mass ppm; a polymerization step in which the monomer is polymerized so that a hydrogel is obtained; and a drying step in which the hydrogel is dried. Also, a method of the present invention for producing polyacrylic acid-based water-absorbent resin includes: a preparation step in which a monomer is prepared from acrylic acid; a polymerization step in which the monomer is polymerized in presence of phenol so that a hydrogel is obtained; and a drying step in which the hydrogel is dried.

Dependencies are inferred from the claim text.