Patent ID: 7312278

Claim:
A water-absorbing agent, which is a particulate water-absorbing agent of which the major proportion is comprised of a water-absorbent resin that is obtained by a process including the step of polymerizing an unsaturated monomer component and has a crosslinked structure, where the particulate water-absorbing agent includes particles having particle diameters of smaller than 850 μm but not smaller than 150 μm in an amount of not less than 90 weight % of all particles of the particulate water-absorbing agent; and where the particles include at least two members selected from the group consisting of: particles (A1) having particle diameters of smaller than 850 μm but not smaller than 600 μm; particles (A2) having particle diameters of smaller than 600 μm but not smaller than 500 μm; particles (A3) having particle diameters of smaller than 500 μm but not smaller than 300 μm; and particles (A4) having particle diameters of smaller than 300 μm but not smaller than 150 μm; and where the water-absorbing agent further has the following properties: a 30-minute absorption capacity of not less than 31 g/g without load for a 0.90 weight % physiological saline (CRC); a 60-minute absorption capacity of not less than 24 g/g under a load of 4.83 kPa for a 0.90 weight % physiological saline (AAP); a saline flow conductivity of not less than 20 (unit: 10 −7 ×cm 3 ×s×g −1 ) for a 0.69 weight % physiological saline (SFC); and an SFC variation index of 0 to 25% wherein the SFC variation index is defined by the following equation (1): SFC variation index (%)=[(standard deviation of SFCs of particles A 1 to A 4)/( SFC of entire particulate water-absorbing agent)]×100 (1).