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:
Oct. 28, 1980
Filed:
Jun. 28, 1979
Applicant:
Inventor:
Ketil Hasvold, Sarpsborg, NO;
Assignee:
Borregaard A/S, Sarpsborg, NO;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21C / ; D21C / ;
U.S. Cl.
CPC ...
162 25 ; 162 55 ; 162 65 ; 162 86 ;
Abstract
Knots separated from sulphite cellulose produced by a sulphite cellulose cooking process are converted to unbleached sulphite cellulose by first separating and defibrating the sulphite knots and then treating the defibrated sulphite knots with oxygen under pressure in an alkaline milieu at an elevated temperature. The resultant cellulose may be bleached by itself, or mixed with sulphite cellulose produced from knot-free cellulose pulp for bleaching therewith.