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:
Mar. 08, 1988
Filed:
Dec. 19, 1985
Applicant:
Inventors:
Raymond C Francis, Don Mills, CA;
Douglas W Reeve, Toronto, CA;
Assignee:
Tenneco Canada Inc. (ERCO division), Islington, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21C / ; D21C / ; D21C / ; D21C / ;
U.S. Cl.
CPC ...
162 65 ; 162 78 ; 162 79 ; 162 80 ; 162 84 ; 162 85 ; 162 88 ;
Abstract
The extent of delignification of chemical pulps by oxygen-containing chemicals, preferably hydrogen peroxide, is enhanced by demethylating the pulp prior to such oxidative delignification, to a degree of demethylation of at least about 30%, preferably at least about 50%. Demethylation may be achieved by chemical treatment of the already-formed pulp or by modification to the pulping process to result in demethylated pulp.