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. 13, 1993
Filed:
May. 19, 1992
Applicant:
Inventors:
Wolfgang Leonhardt, Frankfurt, DE;
Kurt Schmidt, Hammersbach, DE;
Hans U Suess, Gondsroth, DE;
Holger Glaum, Kahl, DE;
Assignee:
Degussa Aktiengesellschaft, Frankfurt am Main, DE;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
D21C / ;
U.S. Cl.
CPC ...
162 76 ; 162 79 ; 162 80 ;
Abstract
A process is disclosed for bleaching wood pulp, cellulose or used paper by treatment the fibre material to be bleached before the bleaching steps with a natural or synthetic zeolite or a layer lattice silicate and an easily decomposable organic complex forming agent, e.g. citric acid.