Patent ID: 7737231

Claim:
A process for preparing a water-absorbent resin, wherein said process comprises: a) polymerizing to completion an α,β-unsaturated carboxylic acid monomer to produce a polymerized water-containing gelated product; b) adding a metal chelating agent at any step in the preparation of the water-absorbent resin, wherein said metal chelating agent is added in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the α,β-unsaturated carboxylic acid; c) adding a reducing agent or an oxidizing agent to the polymerized water-containing gelated product in an amount of 0.001 to 2 parts by weight, based on 100 parts by weight of the α,β-unsaturated carboxylic acid; and d) drying the gelated product thereby yielding a polymerized water-absorbent resin having greater discoloration resistance than a polymerized water-absorbent resin having no reducing or oxidizing agent and no metal chelating agent added thereto.