COMPARISON OF NEWSPRINT FURNISHES USING THE CTP FORMER

The CTP dynamic former has been evaluated for its ability to compare n ewsprint furnishes in a laboratory. Techniques have been developed whi ch allow the CTP former to mimic a newsprint machine. These techniques were evaluated by comparing six newsprint furnishes from five newspri nt mills around the Pacific rim, using matching pulp and newsprint sam ples collected from each machine. For properties strongly linked to fu rnish quality, eg optical properties, tearing resistance and print thr ough, there was a strong relation between commercial and CTP sheets. O ther properties showed a weaker relation eg MD mechanical properties, formation, smoothness, and porosity, While this is partly due to the t wo-sided structure of a CTP sheet, it also suggests that many properti es are influenced by the characterization of an individual paper machi ne. This is reinforced by a comparison of the two sides of commercial newsprint sheets, which often had a poor correlation with each other F or this reason even a perfect laboratory-scale paper machine would not be able to rank completely all of the properties of six different pap er machines. Overall the CTP former is considered satisfactory for its intended role of comparing newsprint furnishes in a controlled enviro nment.