Akzo Nobel N.v.

Eka Chemicals Ab

Akzo Nobel Pulp and Performance Chemicals Ab

Thomas Christopher Greschik

Håkan Fägersten

Hans Erik Johansson-Vestin

Jan Nordin

Magnus Björklund

Hans Johansson-Vestin

Hans-Åke Baltsèn

The present invention relates to a process of bleaching pulp derived from an alkaline pulping process having a hexenuronic acid content prior to the final bleaching stage from about 1 to about 80 mmol/kg dry pulp, said process comprising three chlorine dioxide stages D0, D1, and D2, wherein the chlorine dioxide charges based on the total chlorine dioxide charge in a) D0 is from about 40 to about 60%; b) D1 is from about 30 to about 55%; c) D2 is from about 4 to about 20%, and wherein the final chlorine dioxide stage D2 is performed at a pH from about 2 to about 4.5. The invention also relates to a bleached pulp obtainable by the process.

Bleaching of pulp

The present invention relates to a method of treating an aqueous suspension of bleached pulp derived from an alkaline pulping process comprising dewatering and drying said suspension, wherein the pH of the suspension to be treated ranges from about 6.5 to about 12.

Treatment of pulp

The present invention relates to methods of modifying cellulose fibers and of producing paper which methods include providing a pulp suspension of cellulose fibers and adding a cellulose derivative during the bleaching of the cellulose fibers in an acidic bleaching stage.

Method of treating cellulose fibres with chlorine dioxide and an alkyl cellulose derivative

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Göteborg, Sweden

Thomas Christopher Greschik