AMPHOTERIC STARCH, ITS PRODUCTION AND PRODUCTION OF PAPER OR PAPERBOARD

摘要

PROBLEM TO BE SOLVED: To obtain an amphoteric starch for papermaking, capable of allowing a paper to be made with excellent drainage when added to a paper stock, and capable of providing excellent paper-strengthening effect. SOLUTION: When producing an amphoteric starch for papermaking by introducing a phosphate group to a cationic starch, urea and phosphoric acid is added to the cationic starch having a tertiary or quarternary amine at 0.02-0.05 substitution degree, and the obtained mixture is heated to 110-160 deg.C by a dry process to introduce 0.1-0.7 wt.% phosphate group based on the amount of the solid component of the starch.