Stickies Control with Pectinase for Improving Behavior of Cationic Polymers in a Mixture of Chemithermo-mechanical Pulp and Deinked Pulp

In this work, a pressure-sensitive adhesive (PSA) was used as the model substance for secondary stickies. The dissolved and colloidal substances (DCS) prepared from bleached chemithermomechanical pulp (BCTMP) and the effects of pectinase treatment on the stickies deposition were evaluated. The results showed that the addition of DCS lowered the efficiency of cationic polymers and aggravated the deposition of stickies. As a major component of anionic DCS, polygalacturonic acids can be effectively degraded during pectinase treatment. Therefore, the efficiency of cationic polymers improved, and subsequently they were able to fix the destabilized sticky particles on the fibers, which led to the decrease of stickies deposition. However, the pectinase treatment of DCS insignificantly affected stickies deposition in absence of cationic polymers when the stickies deposition was caused by calcium ions.