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. 18, 1983
Filed:
Dec. 24, 1980
Arthur W Kempf, Warwick, NY (US);
International Paper Company, New York, NY (US);
Abstract
An improved peroxide based brightening and delignifying solution and process for liqnocellulosic pulp, characterized by selective delignification and pulp viscosity retention is disclosed. The process comprises maintaining a pulp slurry to a temperature between 40.degree. C. and 120.degree. C. for 0.5 hours to 8 hours. The slurry comprises lignocellulosic pulp; from 0.1% to 20% by weight based on O.D. pulp of peroxide; from 0.1% to 10% by weight based on O.D. pulp of a metal-containing additive whose metallic portion is selected from the group consisting of tin, titanium, and vanadium; and sufficient acid to maintain the .sub.f H of the slurry between about 1 and about 7. In a preferred embodiment of this invention, a tin additive is employed and the partially delignified and brightened pulp is further bleached with the unconsumed peroxide by adjusting the pH of the slurry to between 8 and 12 and maintaining the temperature of the slurry from 40.degree. C. to 90.degree. C. for 0.1 to 4 hours.