Has excellent water-absorption rate and high equilibrium swell performance, and a method for producing a water-absorbent resin particles is good moderate and handling properties the particle size, to provide a water-absorbent resin particles obtained thereby.
The present invention is a water-soluble ethylenically unsaturated monomer A method for producing a water-absorbing resin particles by reverse phase suspension polymerization, the (A) water-soluble ethylenically unsaturated monomer, internal crosslinking agent absence of presence of HLB 8 to 12 of the surfactant, the step of performing a first time reversed phase suspension polymerization using a water-soluble radical polymerization initiator in a petroleum hydrocarbon dispersion medium, (B ) further step of performing an intermediate crosslinking reaction by adding intermediate crosslinker, in a state in which (C) the surfactant is dissolved in the petroleum hydrocarbon dispersion medium, adding a water-soluble ethylenically unsaturated monomer, absence of internal cross-linking agent, by reverse phase suspension polymerization of a second time using a water-soluble radical polymerization initiator, the step of producing a water-absorbing resin precursor, and, (D) the water-absorbent resin precursor the moisture content, relative to the water-soluble ethylenically unsaturated monomer component constituting the water-absorbent resin precursor After adjusting to 0 to 100% by weight, in the manufacturing method of water absorbing resin particles having a step of post-crosslinking reaction.