USING A DYNAMIC SHEET FORMER (DSF)AS A TOOL TO EXAMINE THE EFFECT OF HYP IN WOOD-FREE PAPER WITH FILLER ADDITION AND WHITE WATER RECIRCULATION

摘要

With an increased interest in using high-yield pulps (HYP) in uncoated and coated wood-free paper, there is a need to develop a laboratory tool to evaluate the effects of HYP under the conditions similar to commercial paper machine operations. It is necessary to make the Dynamic Sheet Former (DSF) sheet with white water recirculation considering the high fines content of HYP and the usually high filler content in fine papers. In this study, we evaluated the use of making oriented DSF sheets under various conditions. The effects of different factors such as operational variables, use of retention aids, and recirculation of white water were examined and clarified in terms of retention of fines and fillers as well as their impact on paper physical properties. The developed method from this study provides a solid basis for examining the true effect of HYP substitution on the properties of uncoated and coated wood-free papers.