PURPOSE: To obtain a highly water-absorptive resin excellent in salt resistance and rate of water absorption, by adjusting the water content of a hydrophilic polymer obtained by polymerising a specified polymerizable monomer with the aid of a specified polymerization initiator to a value within a specified range and crosslinking the polymer with a specified crosslinking agent.
CONSTITUTION: A hydrophilic polymer is produced by polymerizing a polymerizable monomer having a carboxyl or/and carboxylate group [e.g., (meth)acrylic acid] with the aid of a polymerization initiator comprising a combination of a persulfate (e.g., sodium persulfate) with a hydroperoxide (e.g., hydrogen peroxide). After the water content of this polymer is adjusted to 10W40wt%, this polymer is crosslinked with a crosslinking agent having at least two functional groups reactive with the carboxyl and/or carboxylate groups (e.g., ethylene glycol diglycidyl ether) to produce a highly water-absorptive resin. By the use of the above combination as a polymerization initiator, the produced resin can show excellent salt resistance and rate of water absorption and find wide applications including various sanitary materials.
YAMAZAKI HARUMASA
TSUNODA YUUZOU
| JPS56161408A | 1981-12-11 | |||
| JPS5842602A | 1983-03-12 | |||
| JPS58117222A | 1983-07-12 |