Preliminary Results of Effect of Sizings on Enzyme-Enhanced Deinking, 1994 Recycling Symposium Proceedings

Kathie Rutledge-Cropsey, John H. Klungness, Thomas Jeffries, Marguerite Sykes

This report presents results of preliminary research on whether enzymatic deinking is affected by the physical presence of acid and alkaline sizings or by the hydrophobic nature of sized fibers. Three commercial xerographic papers printed with styrene acrylate toner were sized with different agents (rosin/alum, alkenyl succinic anhydride, and alkyl succinic anyhydride) and tested for water resistance. Deinking included medium consistency pulping with enzymes followed by flotation and dewatering. The results were based on image analysis of handsheets and Cobb testing. Papers sized with alkenyl succinic anhydride were the easiest to deink; the most hydrophobic paper (paper sized with rosin/alum) was the most difficult to deink. Deinking efficiency was also affected by the water resistance of the sheet prior to repulping, as measured by the Cobb test. Paper with high water resistance had poor deinking efficiency.