| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing high whiteness bleached kraft pulp, by which the cooking and bleaching properties of hardly cookable and hardly bleachable Eucalyptus material or a material containing the Eucalyptus material can be improved to give the high whiteness TCF (totally chlorine free) or ECF (elemental chlorine free)-bleached pulp. SOLUTION: This method for producing the high whiteness bleached kraft pulp is characterized by applying a series of processes comprising a processing for immersing chips comprising only hardly cookable and hardly bleachable Eucalyptus material or chips containing the Eucalyptus chips in an alkaline aqueous solution, a process for holding the immersed chips at a temperature of 50 to 95°C for a holding time of 5 to 90 min, a process for taking out the alkali extract solution and washing the left wood chips, a cooking process for producing the unbleached pulp having a Kappa value of 14 to 22, and a process for subjecting the unbleached pulp to a TCF bleaching or an ECF bleaching to produce the bleached pulp having a whiteness degree of≥84%. COPYRIGHT: (C)2004,JPO
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