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. 22, 1988
Filed:
Sep. 15, 1986
Applicant:
Inventors:
Robert J Michalowski, Midland, MI (US);
Steven H Christiansen, Richwood, TX (US);
Jimmy Myers, Sweeny, TX (US);
David A Wilson, Richwood, TX (US);
Assignee:
The Dow Chemical Company, Midland, MI (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
D21C / ;
U.S. Cl.
CPC ...
162 17 ; 162 19 ; 162 76 ; 162 78 ; 162 80 ;
Abstract
Bleaching of wood pulp is improved by the combination of a pretreatment of the pulp with a polyaminocarboxylic acid, e.g. ethylenediaminetetraacetic acid, prior to bleaching with an alkaline aqueous peroxide solution containing a stabilizing amount of an aminophosphonic acid derivative together with a polymer of an unsaturated carboxylic acid or amide or an alkylsulfonic acid substituted amide.