Patent ID: 7935774

Claim:
A particulate water-absorbent polymer obtained through a method comprising: polymerizing a monomer aqueous solution (B) containing (i) at least one of monomer (A) that is capable of forming a water-absorbent polymer by polymerization, (ii) at least one of crosslinking agent, (iii) at least of polymerization initiator and (iv) an organic phosphorous compound in an amount of not less than 1 ppm by mass but not more than 100 ppm by mass with respect to the monomer (A) so as to obtain a hydrogel polymer; and thermally drying the hydrogel polymer; the particulate water-absorbent polymer exhibiting an L value(Lightness) of 70 or higher in Hunter's Lab color system after 7-day exposure to atmosphere of 70±1° C. of temperature and 65±1% of relative humidity and comprising iron in an amount based on Fe 2 O 3 of not less than 0.001 ppm by mass but not more than 5 ppm by mass with respect to the particulate water-absorbent polymer.