New Generation of Copolymers for Retention - Drainage - Formation and Coated Broke Applications, 1999 Papermakers Conference Proceedings

Charles Hunter, Ken Henderson, Pat McInnis, Joe Miknevich

A new retention – drainage – formation chemistry has been developed for wet-end applications that is effective across many grades of paper. Papermaking demands have exceeded what traditional organic coagulants can accomplish. New process conditions and papermaking goals have created a need for a flexible and robust new chemistry. The new copolymers discussed in this study represent what are traditionally known as coagulants to the papermaker, but show enhanced performance due to their dual nature. It was found that in many cases, these copolymers perform better than traditional coagulants in enhancing drainage, retention, and sheet formation. On machine, this chemistry was found to increase press solids and decrease steam usage, all at higher machine speeds. The coagulants are medium molecular weight copolymers of acrylamide and DADMAC made under different and unique process conditions. The authors propose a hybrid mechanism of combined electrostatic patch - charge neutralization and bridging flocculation. The capacity for these copolymers to perform both through charge – patch and bridging allows them to improve retention and drainage when compared to typical organic coagulants in various furnishes.