TMP Processing Conditions to Produce Pulps for Mechanical Printing Papers- Effects on Surface Properties, 1996 Pulping Conference Proceedings

R. Amiri, G. Stepien, J. R. Wood

Pulp and Paper Research Institute of Cananda

We evaluated the effect of specific energy, refining intensity and reject rate on the quality of low freeness pulps for light-weight coated and supercalendered mechanical printing papers. Sheets were prepared from furnishes containing pilot plant TMP pulps, kraft pulp and clay using the Dynamic Sheet Former (DSF). The sheets were calendered to specific volume, roughness and gloss levels within the range of available commercial LWC and SCC sheets.

Mechanical pulps prepared with high-intensity refining gave sheets with comparable properties to those made with conventional pulps but with significantly less energy consumption. Both high-intensity refining, and increased specific energy, reduced the changes in gloss and roughness after application of water to these sheets. Under the experimental conditions used in the present work overall reject rate had little effect on the properties of the sheets. The long fibre in the refined rejects had a lower coarseness than the accept pulps.