Water-absorbing agent and production process therefor

摘要

The invention provides a water-absorbing agent, which has high absorption capacity and excellent absorption efficiency under increased pressure and can display excellent water absorption properties when used for sanitary materials even if the resin concentration of a water-absorbent resin is high. The water-absorbing agent has an absorption capacity of 30 (g/g) or more and the below-defined absorption efficiency of 0.7 or more under increased pressure. This agent can be obtained by heating in the presence of a surface-crosslinking agent a water-absorbent resin having an absorption capacity of 40 (g/g) or more and an amount of an eluting component of 1 wt % or less relative to the water-absorbent resin, or by: polymerizing a water-absorbent resin in the presence of a chain transfer agent; treating the polymerized resin with a hydrophilic solution; and heating the treated resin in the presence of a surface-crosslinking agent. $$