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US 2014/0371442 A1Published application
Low viscosity kraft fiber having reduced yellowing properties and methods of making and using the same
AssigneeGP Cellulose GmbH
InventorsArthur J. Nonni, Charles E. Courchene, Phillip R. Campbell, Steven C. Dowdle, Joel Mark Engle
Life of this patent
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Abstract
A bleached softwood kraft pulp fiber with high alpha cellulose content and improved anti-yellowing is provided. Methods for making the kraft pulp fiber and products from it are also described.
Claims18
1-15. (canceled)
A method for making an oxidized kraft pulp comprising:
- digesting and oxygen delignifying a softwood cellulose pulp to a kappa number of less than 8;
- bleaching the cellulosic kraft pulp using a multi-stage bleaching process;
- and
- oxidizing the kraft pulp during at least one stage of the multi-stage bleaching process with a peroxide and a catalyst under acidic condition, wherein the multi-stage bleaching process comprises at least one bleaching stage following the oxidation stage.
1 more element
A softwood kraft fiber having improved anti-yellowing characteristics made by a method which does not include a pre-hydrolysis step comprising:
- digesting and oxygen delignifying a softwood cellulose fiber to a kappa number of less than 8;
- bleaching the cellulosic kraft pulp using a multi-stage bleaching process;
- and
- oxidizing the kraft pulp during at least one stage of the multi-stage bleaching process with a peroxide and a catalyst under acidic condition, wherein the multi-stage bleaching process comprises at least one bleaching stage following the oxidation stage.
1 more element
An oxidized bleached softwood kraft fiber exhibiting:
- a total carbonyl content of less than about 2.5 mmoles/100 g and a CED viscosity of less than about 5 mPa·s.
Dependencies are inferred from the claim text.