Modern Chemical Approach to Improving Paper Machine Effeiciencies in OCC Containing Liner and Medium Grades, 1997 Recycling Symposium Proceedings

With increasing environmental pressures, mills are forced into higher levels of system closure and greater utilization of secondary fiber resources. New technologies for retention and drainage programs are necessary to handle the accompanying higher levels of interfering substances and anionic trash. Retention and drainage aid (RDA) programs, such as cationic polyacrylamides (PAM’s), starch/alum, and PAMcoagulants, lose considerable efficiency as trash loading increases.

A program, which provides a high fixing capacity to reduce these trash levels along with sufficient molecular weight to achieve retention, is necessary. Use of an RDA system incorporating a high charge density modified polyethyleneimine can achieve these results. RDA programs employing an in-line blend of a modified polyethyleneimine (PEI) and a cationic PAM have shown excellent results worldwide in a number of liner board/medium applications. Mill examples have shown 2.0 - 9.5% increases in gross production. Other cases have demonstrated a 23% reduction in chemical costs (per ton) while maintaining production.