To provide a method for efficiently producing a particle type water-absorbing resin having excellent physical properties at low cost while securing high productivity.
In the method for producing a water-absorbing resin, a process (1) for polymerizing a monomer aqueous solution, a process (2) for drying an obtained hydrous gel polymer, a process (3) for crushing a dried product or crushing and classifying the dried product for controlling grain size, and a process (5) for performing surface crosslinking on water-absorbing resin powder with controlled grain size are carried out successively. In the method, a process (4) for performing second heating and drying additionally on the water-absorbing resin powder with controlled grain size is also carried out before the process (5) for performing surface crosslinking. The water content (a loss on drying for 3 hours at 180C) of the water-absorbing resin fed to the surface crosslinking process (5) is 0-3 wt.%.
MATSUMOTO MAKOTO
TAKAAI TOSHIHIRO
DAIROKU YORIMICHI
FUJINO SHINICHI
KATO SEIJI
