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:
Feb. 14, 1995
Filed:
Oct. 18, 1993
Applicant:
Inventor:
Ted Y Tsai, Harriman, NY (US);
Assignee:
International Paper Company, Purchase, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21C / ; D21C / ; D21C / ;
U.S. Cl.
CPC ...
162 57 ; 162 65 ; 162 89 ;
Abstract
In a multi-stage bleaching sequence for kraft pulps employing a chlorine-containing bleaching agent in the first and final stages thereof and an intermediate alkaline extraction stage, the improvement for enhancing the brightness of the pulp and reducing the quantity of dioxin or chlorinated organics comprising contacting the pulp, in a mixer, at an acidic pH and a temperature of below about 60.degree. C. with a mixture of ozone and oxygen at a pressure of between about 60 and 80 psig wherein the quantity of ozone introduced to the pulp is between about 0.2% and about 0.4%, based on pulp.