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:
Dec. 09, 1997
Filed:
Jan. 19, 1996
Lars Harald Petander, Vaasa, FI;
Tore Anders Duvnas, Maksamaa, FI;
Kemira Oy, Espoo, FI;
Abstract
The invention relates to a process for the production of paper by adding to an aqueous fiber suspension, which possibly contains a filler, auxiliary agents for improving retention and/or dewatering, the auxiliary agents being a cationic long-chain polyacrylamide and an aluminum salt, and by dewatering the obtained fiber suspension during the sheet-forming stage. According to the invention, the said aqueous fiber suspension, possibly containing a filler, to which the cationic long-chain polyacrylamide has first been added, is subjected to shearing forces, whereafter there is added to it, directly before sheet forming, a polymeric aluminum salt or an aluminum salt, in which case a base or an acid is added, when necessary, to the said fiber suspension so that the pH be within the range 7-9 before the sheet forming, in which case aluminum hydroxy particles having anionic surface charges will be formed in situ.