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:
Apr. 24, 2001
Filed:
Jun. 29, 1993
Applicant:
Inventors:
François Desprez, Brussels, BE;
Johan Devenyns, Brussels, BE;
Nicholas Troughton, Brussels, BE;
Paul Essemaeker, Brussels, BE;
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21C 9/14 ; D21C 9/147 ; D21C 9/153 ; D21C 9/16 ;
U.S. Cl.
CPC ...
D21C 9/14 ; D21C 9/147 ; D21C 9/153 ; D21C 9/16 ;
Abstract
Process for bleaching a chemical paper pulp to a brightness of at least 89° ISO, consisting in subjecting the pulp to a treatment sequence of several stages including a final bleaching stage with hydrogen peroxide in alkaline medium carried out in the presence of at least one stabilising agent and at a consistency of at least 25% by weight of solids, the stages preceding this final stage having purified the pulp so that its manganese content does not exceed 3 ppm by weight with respect to the solids and that the pulp has been delignified beforehand to a kappa number not exceeding 5.