The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 12, 2022
Filed:
Jan. 18, 2018
Centre Technique DE L'industrie Des Papiers, Cartons ET Celluloses, Gieres, FR;
Institut Polytechnique DE Grenoble, Grenoble, FR;
Gerard Mortha, Laissaud, FR;
Jennifer Marcon, Saint Pierre du Mont, FR;
Nathalie Marlin, Saint Martin d'Heres, FR;
Auphelia Burnet, Montferrat, FR;
Michel Petit-Conil, Grenoble, FR;
CENTRE TECHNIQUE DE L'INDUSTRIE DES PAPIERS, CARTONS ET CELLULOSES, Gieres, FR;
INSTITUT POLYTECHNIQUE DE GRENOBLE, Grenoble, FR;
Abstract
The present invention relates to a method for bleaching an unbleached or pre-bleached paper pulp comprising at least the following consecutive steps: a) preparing an unbleached or pre-bleached paper pulp having a pH of at least 8, b) bringing the paper pulp obtained at the end of step a) into contact with chlorine dioxide, c) when the pH of the paper pulp obtained from step b) is lower than 10, adding at least one Brønsted base to the paper pulp, d) adding hydrogen peroxide to the paper pulp obtained at the end of step c), e) maintaining the paper pulp obtained at the end of step d) in a first bleaching tower, f) optionally, adding sulphuric acid to the paper pulp obtained at the end of step e) and maintaining the obtained paper pulp in a second bleaching tower, the method dispensing with the need for a step of washing the paper pulp before the end of step e), and, if applicable, before the end of step f).