Aminated poly-N-vinylformamide as a modern retention aid of alkaline papersizing with acid rosin sizes

Partially aminated poly-N-vinylformamides (APNVF) were prepared by the hydr olysis of PNVF and used as the retention aid of rosin size. The dual retent ion aids system, consisting of this modern polymer and aluminum sulfate (al um) for neutral-alkaline paper sizing using acid rosin sizes, was evaluated by experiment. The results indicated that APNVF was very effective and a s mall amount of the polymer used together with alum considerably increased t he size retention and sizing degree of paper under neutral-alkaline conditi ons. The cationic charge density of APNVF significantly influenced the sizi ng efficiency of the rosin sizes. Furthermore, the retention of alkaline fi ller CaCO3 and paper strength were improved by the polymer addition. It is clear that the polymer can be used as a multifunctional additive for paperm aking. (C) 2000 John Wiley & Sons, Inc.