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US 10,174,455 B2Granted
Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
AssigneeGP Cellulose GmbH
InventorsArthur J. Nonni, Charles E. Courchene, Blair Roderick Carter
Life of this patent
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Abstract
A pulp fiber with an enhanced carboxyl content resulting in improved antimicrobial, anti-yellowing and absorptive properties. Methods for making the kraft pulp fiber and products made from it are also described.
Claims21
A method of making a modified acid-treated kraft fiber comprising:
- subjecting cellulose fiber to a kraft pulping step;
- oxygen delignifying the cellulose fiber following the kraft pulping step;
- bleaching the cellulose fiber following oxygen delignification using a multi-stage bleaching process;
- wherein one or more of the stages of the multi-stage bleaching process is an oxidation stage comprising treating the cellulose fiber with a peroxide and a catalyst under acidic conditions;
- wherein two or more of the stages of the multi-stage bleaching process are carboxylating acid stages comprising treating the cellulose fiber with the addition of a combination of either sodium chlorite and hydrogen peroxide or chlorine dioxide and hydrogen peroxide;
- and
- wherein at least one carboxylating acid stage precedes at least one oxidation stage and at least one carboxylating acid stage follows at least one oxidation stage.
4 more elements
A method of making a modified acid-treated kraft fiber comprising:
- subjecting cellulose fiber to a kraft pulping step;
- oxygen delignifying the cellulose fiber following the kraft pulping step;
- bleaching the cellulose fiber following oxygen delignification using a five stage bleaching process comprising a sequence of (C/A)(OX)(C/A)(OX)(C/A), wherein C/A refers to a carboxylating acid stage comprising treating the cellulose fiber with chlorine dioxide and hydrogen peroxide, and wherein OX refers to an oxidation stage comprising treating the cellulose fiber with an iron catalyst and hydrogen peroxide at an acidic pH.
A method of making a modified acid-treated kraft fiber comprising:
- subjecting cellulose fiber to a kraft pulping step;
- oxygen delignifying the cellulose fiber following the kraft pulping step;
- bleaching the cellulose fiber following oxygen delignification using a five stage bleaching process comprising a sequence of D0(OX)(C/A)(OX)(C/A), wherein C/A refers to acid-treatment stages comprising treating the cellulose fiber with chlorine dioxide and hydrogen peroxide, D refers to a chlorine dioxide stage without the addition of hydrogen peroxide, and wherein OX refers to oxidation stages comprising treating the cellulose fiber with an iron catalyst and hydrogen peroxide at an acidic pH.
Dependencies are inferred from the claim text.