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Method for the alkaline bleaching of pulp with a peroxyacid based oxygen bleaching species using an agglomerated bleach activator

  • US 6,569,286 B1
  • Filed: 08/08/2001
  • Issued: 05/27/2003
  • Est. Priority Date: 09/30/1998
  • Status: Expired due to Term
First Claim
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1. A process for the bleaching of wood and non-wood pulp comprising the steps of:

  • a) adding an aliquot of agglomerate from a bulk solid dispensing means to a dilute solution of hydrogen peroxide, wherein the agglomerate comprises;

    a bleach activator;

    a peroxide soluble binder;

    a dispersing system comprising a wetting agent which is low foaming and does not discolour on exposure to temperatures of up to 120°

    C. and optionally a salt, which is highly soluble in hydrogen peroxide; and

    wherein the amount of hydrogen peroxide is more than twice that which can react with the activator;

    b) allowing the bleach activator to substantially completely react with the hydrogen peroxide in the presence of a sequestrant which is provided in the agglomerate and/or the dilute hydrogen peroxide to generate a peroxyacid based oxygen bleaching species in a bleaching solution;

    c) adjusting the pH of the bleach solution by adding alkali; and

    d) bleaching the pulp by contacting it with the bleaching solution under alkaline conditions.

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