Mechanisms of neutral-alkaline paper sizing with usual rosin size using alum-polymer dual retention aid system, Journal of Pulp and Paper Science, January 2001, Vol. 27(1)

F. Wand and H. Tanaka

Cationic polymers, such as partially aminated poly-N-vinylformamide, copoly (trimethylaminoethyl acrylate-acrylamide), polyethyleneimine, and poly (diallyl dimethyl ammonium chloride) were used, respectively, cooperating with alum as the retention aids of neutral-alkaline paper sizing with usual rosin sizes, and the mechanisms of this sizing system were elucidated. It was found that conventional acid rosin sizes could work well even in the alkaline region when some alum-polymer dual retention aid systems were introduced. Both aluminum and rosin size content in paper were increased by the addition of suitable polymers. The polymers with amide group in part and relatively lower charge density were effective for rosin soap size. It is supposed that suitable cationic polymers can form stable complexes with rosin size particles through hydrogen bonds and with aluminum cations by coordination bonds so as to prevent rosin particles and aluminum cations from the destructive action fo OH- ion under neutral-alkaline conditions.