Particulate water absorbing agent including polyacrylic acid (polyacrylate) based water absorbing resin as a principal component, method for production thereof, water-absorbent core and absorbing article in which the particulate water absorbing agent is used
As a characteristic that had not been known conventionally at all, “permeability potential under pressure (PPUP)” of a particulate water absorbing agent is regulated, and further, “range of particle size distribution” and “coloring” are concomitantly regulated. The present invention is directed to a particulate water absorbing agent having the following (a) to (c):(a) permeability potential under pressure (PPUP) being 50 to 100%(b) yellowness index (YI) being 0 to 10, and rate of change of yellowness index (ΔYI) being 100 to 150% following a coloring acceleration test for 14 days at 70±1° C. and the relative humidity of 95±1% and(c) particles of smaller than 150 μm specified by standard sieve classification accounting for 0 to 5% by weight, weight average particle diameter (D50) being 200 to 550 μm, and logarithmic standard deviation (σζ) of particle size distribution being 0.20 to 0.40.
