A NOVEL SHEET PREPARATION METHOD FOR INK CONTENT MEASUREMENT IN PAPER RECYCLING, 2010 TAPPI PEERS Conference

Please Note: This document will be available in PDF format in the "My Electronic Documents" link on the home page once your order has been completed. Please make sure you have the latest version of Acrobat Reader. Click on the Acrobat Reader icon to check for the latest version, it’s FREE. To print a hardcopy of a PDF file correctly you must have a postscript printer. If you are not sure if your printer is a postscript printer please refer to your owner’s manual.

The amount of ink (ERIC) can be assessed with a measured or constant scattering coefficient. The use of a measured scattering coefficient has been recommended, because a constant scattering coefficient biases the values obtained if the fines or filler content of pulp changes. The standard practice of preparing a sheet on a wire screen enables the measurement of the scattering coefficient, but results in a substantial loss of fines compared to pad preparation on a filter paper. However, the measurement of the scattering coefficient from pads is prevented due to opacity limitations. Hence, all the standardised methods have a weakness that potentially biases the results obtained.

This paper introduces a novel method for preparing low grammage sheets on a high-retention filter paper. The applicability of the proposed method was studied using an ONP/OMG furnish in a 50/50 ratio in terms of retention, scattering coefficient, reflectance and residual ink values, while repeatability and sidedness are also discussed. Comparison of the novel sheet to standard pads and sheets showed that a high retention of fines and ink can be obtained with this method, while also enabling the measurement of the scattering coefficient. Thus, ink content measured from a sheet prepared in this way can be considered free of the limitations seen in other media and corresponds to the original state of the pulp better than a conventionally prepared sheet.