WET PAPER-STRENGTHENING AGENT AND METHOD FOR IMPROVING WET PAPER STRENGTH

摘要

PROBLEM TO BE SOLVED: To provide a wet paper-strengthening agent that comprises a polyamidine-based water-soluble polymer producible at a low cost in place of a conventional high-cost amidine-based water-soluble polymer when an amidine-based water-soluble polymer is applied as a papermaking internal additive and a method for improving wet paper strength.;SOLUTION: The method for improving wet paper strength includes adding an amidine structure unit-containing water-soluble polymer obtained by subjecting a copolymer of (meth)acrylamide and (meth)acrylonitrile to a Hofmann reaction, neutralizing the reaction product with an acid and heat-treating the neutralized product to a papermaking raw material before papermaking.;COPYRIGHT: (C)2009,JPO&INPIT