METHOD FOR MANUFACTURING POLYACRYLIC ACID (POLYACRYLATE)-BASED WATER-ABSORBENT AGENT, AND WATER-ABSORBENT AGENT

摘要

The purpose of the present invention is to provide a method for manufacturing a water-absorbent agent, whereby the ability to produce the water-absorbent agent is enhanced or the amount of a residual surface crosslinking agent is reduced (or anti-caking properties are enhanced) in the manufacture of a high-performance (particularly, high liquid permeability or anti-caking properties) water-absorbent agent, whereas a surface crosslinking step is rate-limiting in the current state of the art. In this method for manufacturing a water-absorbent agent, an additive selected from a compound containing a polyvalent metal cation, water-insoluble inorganic fine particles, and a cationic polymer compound is used, and surface crosslinking, particularly surface crosslinking by an alkylene carbonate compound, is performed under conditions in which the temperature in a heat treatment system is controlled to 100-300° and the dew point to less than 45°C.