New Microparticulate System to Improve Retention/Drainage in Fine Paper Manufacturing, 2002 Technology Summit Proceedings

Bruno Chabot

Retention and drainage in alkaline papermaking are affected by increased addition of recycled fibers and higher levels of white water system closure. These conditions result in systems with higher dissolved and suspended material concentrations and increased conductivity which significantly affect retention and drainage aids performance during papermaking. Organic and inorganic microparticle systems were developed in recent years to improve retention and drainage of fine papermaking furnishes. However, all these microparticle systems were used with linear polyacrylamide which tends to form specific "floc" types. Also, higher conductivity in alkaline wet ends significantly reduces the effectiveness of retention additives. A new microparticle system is proposed to improve retention of precipitated calcium carbonate (PCC) filler, drainage, and sheet properties. Two new cationic polyacrylamides along with a bentonite microparticle were compared to a traditional microparticle system. Results showed that a branched cationic polyacrylamide flocculant used in conjunction with bentonite improved first pass retention, first pass ash retention, and drainage over the traditional microparticle system. It was also found that branched polymers were less affected by increased turbulence compared to the linear polyacrylamide flocculant.