Production process for hydrophilic polymer

Abstract

The present invention provides a production process to obtain a hydrophilic polymer, having a low residual monomer content, with good productivity while keeping the properties of a hydrogel polymer resultant from polymerization. In a drying process for a hydrogel polymer, the hydrogel polymer is dried under normal pressure at a material temperature of not higher than 90° C. until the water content of the hydrogel polymer reduces to 15˜40 weight %, and then the hydrogel polymer is kept for not shorter than 10 minutes either in a state where the change of the water content of the hydrogel polymer is within 5 weight % and where the material temperature is in the range of 70˜120° C. or in a state where the water content of the hydrogel polymer is in the range of 15˜40 weight % and where the material temperature is in the range of 70˜120° C., and then the hydrogel polymer is finish-dried.

Dependencies are inferred from the claim text.