METHOD OF DYEING OR PRINTING HYDROGEL RESIN

摘要

A method of dyeing or printing hydrogel resin which comprises the steps of impregnating hydrogel resin or a hydrophilic waterexpansible high polymer with a water-soluble dyestuff or leuco or colorless compound thereof having a great affinity to said hydrogel resin; and treating said water-soluble dyestuff or leuco or colorless compound thereof to render them water insoluble and capable of presenting a color, said method being suitably applied in making a soft contact lens prepared from the hydrogel resin.