PURPOSE: To obtain a hydrophilic polymer with good productivity by the aq. soln. polymerization of a specified α,β-ethylenically unsatd. monomer in the presence of a radical polymn. initiator.
CONSTITUTION: A monomer component comprising 20-25mol% hydroxylated α,β-ethylenically unsatd. monomer (a), 5-30mol% carboxylated α,β-ethylenically unsatd. monomer (b) and 93-45mol% α,β-ethylenically unsatd. monomer (c) contg. a carboxylic acid salt group [wherein the sum of (b) and (c) is 98-75mol%] is subject to aq. soln. polymerization in the presence of a radical polymn. initiator. The aimed hydrophilic polymer having a water absorption ratio of 1-30 is obtd. by heat-treating the obtd. polymer at 130-250°C for 10min-20hr, thereby forming a crosslinked structure by the reaction of the hydroxyl groups with the carboxyl groups.
IWASAKI KAORU
FUJIWARA TERUAKI
