IMPACT OF HIGH YIELD PULPS ON WET END CHEMISTRY OF TYPICAL FINE PAPER APPLICATIONS -UNDERSTANDING AND ALTERNATIVE CORRECTIVE STRATEGIES

摘要

High brightness specifications for high yield pulps (HYP) require aggressive, high pH oxidative bleaching strategies. This, combined with often limited washing capacity makes HYP a significant source of wet end contamination for typically “clean” fine paper operations. Increased conductivity, cationic demand and extractives content all affect performance of wet end additives in terms of retention, drainage and machine cleanliness. Understanding sources of detrimental effects and utilization of control strategies already existing in mechanical paper grades production will prove valuable in fine paper production when content of mechanical fiber in the furnish increases. This paper will focus on three areas greatly affected by HYP addition – conductivity, cationic demand and extractives content.