Patent ID: 8822373

Claim:
A particulate water absorbing agent, comprising: a polyacrylic acid and/or a salt thereof water absorbent resin as a main component, wherein the water absorbent resin is polymerized from a monomer solution comprising an acrylic acid monomer and 10-200 ppm of a methoxyphenol by mass with respect to the acrylic acid monomer, and wherein the water absorbent resin internally includes: an aliphatic α-hydroxycarboxylic acid and/or a salt thereof, and an aminocarboxylic acid or aminophosphate metallic chelating agent, and wherein the water absorbent resin satisfies the following condition (a), (a) an amount of particles whose particle diameter is less than 150 μm ranges from 0 to 5 mass %, and a mass average particle diameter (D50) ranges from 200 to 600 μm, and a particle size distribution logarithmic standard deviation (σζ) ranges from 0.20 to 0.40.