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. 07, 1997
Filed:
Feb. 08, 1995
R Fred Chasse, Lake George, NY (US);
Bruno S Marcoccia, South Glen Falls, NY (US);
Kaj O Henricson, Kotka, FI;
Ahlstrom Machinery Inc., Glen Falls, NY (US);
Abstract
The pretreatment of cellulosic fibrous material is adjusted to improve pulp strength. The cellulosic material is initially pretreated with a low temperature alkaline liquid (e.g. 80.degree.-110.degree. C.), and then with a higher temperature (but still below cooking temperature), higher alkali concentration liquor. Only then is the material--which has alkali which has completely penetrated the cellulose fiber walls--subjected to cooking with white liquor at a temperature of about 150.degree.-180.degree. C. Green, white, or black liquor can be used in the first impregnation zone, while white liquor (with polysulfide addition) is preferably used in the second zone.