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:
Jun. 23, 1987
Filed:
Oct. 01, 1986
Applicant:
Inventor:
William B Darlington, Wadsworth, OH (US);
Assignee:
PPG Industries, Inc., Pittsburgh, PA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
D21C / ; D21C / ;
U.S. Cl.
CPC ...
162 72 ; 162 78 ;
Abstract
A method is disclosed for achieving additional bleaching of a wood pulp following a peroxide bleaching of the pulp, the method involving added thiourea to the slurry at a pH of 4 to 7 in the presence of residual peroxide and thereafter maintaining the slurry at a pH of 8 to 11.