Forming and Properties of Quasi-Laboratory Paper Sheets, 1999 International Paper Physics Conference Proceedings

Marco Lucisano, Bo Norman

A method for the forming of 20 g/m 2 laboratory paper sheets with quasi-random fibre distribution has been developed. The formation and strength were compared with those of 20 g/m 2 hand-sheets formed in a Finnish laboratory sheet former. The forming procedure was based on extremely slow drainage of a dilute suspension of carboxymethylated pulp fibres in a sucrose solution with the same density as that of cellulose. The residual sugar was washed away from the wet sheets with de-ionised water before pressing and drying according to the standard laboratory procedures. Radiographic formation measurements demonstrated the importance of both fibre flocculation and hydrodynamic self-healing effects on the structure of paper. Statistically significant differences in the tensile strength of the two paper types are shown. Both the tensile index and the tensile stiffness index of quasi-random sheets were lower than the corresponding values for more traditionally formed paper. Further, sheets formed by quick drainage of the sugar solution showed a significant improvement of paper formation but no improvement of the sheet strength.