Process for preparing hydrophilic resins

A process for preparing a radiation-curable hydrophilic resin is provided. The process comprises modifying a dicarboxylic acid having at least three ether linkages per one molecule (A) or a polyester having terminal COOH groups (B), prepared by condensing (A) with a diol having at least three ethel linkages per one molecule, with an OH- or epoxy-containing vinyl monomer (C). Upon irradiation with electron beams (0.1 to 20 Mrad/sec) or light (3000 to 8000 A, in the presence of a photosensitizer) the resin cures to yield a crosslinked polymer suitable for use as a surface treating agent for fibers, molded products and films, a printing plate material and FRP. In one example (parts), a polyester (B) was prepared by condensing succinic anhydride (100) with polypropylene glycol of MW 600 (300) and the product was then reacted with Et 2-OH-acrylate (116) as (C) to give a modified resin. One hundred parts thereof were mixed with acrylic acid (20), and a polyethylene film was coated with the mixture. Irradiation with electron beams (dose rate 2 Mrad/sec, dose 3 Mrad) gave a polyethylene film of good printability and a permanent hydrophilic character. (Kaichi, S.)