Water-absorbing resin, and absorbent article

Abstract

Provided is a water-absorbing resin that exhibits excellent absorption performance and a high permeation rate with respect to liquids to be absorbed, and that effectively reduces liquid leakages, even in an absorbent body using a large amount of the water-absorbing resin. The water-absorbing resin is formed from a polymer of a water-soluble ethylenically unsaturated monomer, and when a cross-sectional image of the water-absorbing resin obtained by X-ray computer tomography is observed, the ratio (cavity area ratio) as calculated by formula (I) of the area of cavity portions in the cross-sectional image is 2-10%. The liquid flow rate index as calculated by formula (II) when a physiological saline liquid column flow rate test is performed on the water-absorbent resin having a particle diameter of 250 to 500 μm at 37° C. is 5-20. (I) Cavity area ratio [%]={total cross-sectional area (B) of cavity portions in the water-absorbing resin/(total cross-sectional area (A) of resin portions in the water-absorbing resin+total cross-sectional area (B) of cavity portions in the water-absorbing resin)×100} (II) Liquid flow rate index={liquid flow rate (CPR2) during 10 second period between 50 seconds and 60 seconds after initiation of liquid flow/liquid flow rate (CPR1) during 10 second period after initiation of liquid flow}×100

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