PAPER STRENGTHENING AGENT FOR MOISTENING PAPER

摘要

PROBLEM TO BE SOLVED: To provide a paper strengthening agent for moistening paper that is a water-soluble blocked urethane polymer and admixed to paper-making stock and deblocked in the drier part of the conventional paper-making machine. SOLUTION: A water-soluble blocked urethane polymer bearing hydrophilic groups and keto oxime-chain terminal-blocked aromatic isocyanate groups is added to the paper-making stock as a moistening paper strengthening agent to form the web and the formed web is dried at a temperature of <=130 deg.C.