Superheated Steam Drying of Paper from Chemithermomechanical Pulp, 1993 Papermakers Conference Proceedings

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 effect on paper properties of superheated steam drying of CTMP paper is reported. Strength properties, such as Scott internal bond, burst index, and tensile index, were up to 32 %higher for steam dried paper than for paper dried in air under the same conditions. Lower scattering coefficients for the steam dried sheets are consistent with increased relative bonded area being the mechanism for the increased strength. The proposed mechanism accounts for the changes in physical and optical properties through softening of lignin and hemicelluloses within the fibres, rendering the fibres more flexible, allowing better interfibre contact, better bonding, and thereby providing a stronger sheet. This softening is a consequence of the sheet temperature from the onset of drying being significantly higher for drying in superheated steam than in air.