Effect of Various Mechanical and Chemical Treatment of Ray Cells on Sheet Properties and Linting, 1999 International Mechanical Pulping Conference Proceedings

John Wood, Xia Zhang, Oleg Chagaev & Mustafa Stationwala

Pulp and Paper Research Institute of Canada

K. Goel & P. M. Shallhorn

Domtar Innovation Centre

S. Beaulieu

Alliance Forest Products Inc.

Fine material, substantially enriched in ray cells, was obtained as the underflow from hydrocyclone separation of spruce TMP white water. It was thickened then refined, ground, or ball-milled with and without prior treatment by alkaline peroxide. The six types of material were added to decker TMP from which 10% of the material with lowest specific surface had been removed, or to fines-free kraft pulp. Handsheets were prepared from the resultant pulp mixtures and tested for bulk and surface strength properties. None of the physical treatments produced much improvement in the ability of the ray cell material to bond into the sheet. The chemical treatment, on the other hand, improved both bulk and surface strengths of the sheets, even without accompanying physical treatments. It should therefore be possible to reduce newsprint linting by removing a fraction of fines, rich in ray cells, from the TMP white water system using a small diameter hydrocyclone, treating the fraction with alkaline peroxide and returning it to the pulp stream.