| abstract |
Provided is a method of preparing a superabsorbent polymer, which enables the preparation of the superabsorbent polymer exhibiting an improved absorption rate while maintaining excellent absorption performances. The method of preparing a superabsorbent polymer includes the steps of carrying out a crosslinking polymerization of a water-soluble ethylene-based unsaturated monomer having acidic groups which are at least partially neutralized, in the presence of an internal crosslinking agent having a predetermined chemical structure to form a water-containing gel polymer; gel-pulverizing the water-containing gel polymer; drying, pulverizing, and size-sorting the gel-pulverized water-containing gel polymer to form a base polymer powder; and carrying out a surface crosslinking of the base polymer powder by heat treatment in the presence of a surface crosslinking agent, wherein the gel-pulverizing step is carried out by extruding the water-containing gel polymer through a porous plate having a plurality of holes using a screw extruder mounted inside a cylindrical pulverizer under the condition that a chopping index is 28 (/s) or more. |