| 摘要 |
PROBLEM TO BE SOLVED: To obtain a water-absorbent resin having a good time stability in a water-contg. state by specifying the total amt. of a polymn. initiator used based on the amt. of a monomer and by changing the addition conditions of the initiator within a time from the beginning to the end of the polymn. SOLUTION: The total amt. of a polymn. initiator is set at 0.01-10 pts.wt. based on 100 pts.wt. water-soluble monomer. At least 1/4 of the total amt. of the initiator is added before the monomer conversion reaches 50%. The rate of addition of the initiator to the polymn. system is changed at least once within a time from the begining to the end of the polymn. (excluding the starting time and ending time of the polymn.). The highly water-absorbent resin is prepd. by supplying a water-soluble monomer or its water soln. into a dispersion medium contg. a hydrophobic org. solvent and subjecting the monomer or soln. to reversed phase suspension polymn. in the presence of an ionic surfactant. Azoic polymn. initiators and oxidative polymn. initiators, such as 2,2'-azobis(2- amidinopropane)dihydrohalide, are listed as the polymn. initiator.
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