METHOD FOR ON-SITE GLYOXYLATION OF POLYACRYLAMIDE

Method for on-site glyoxylation of polyacrylamide in paper mill, board mill or the like is disclosed. Discontinuous batch glyoxylation reaction of aqueous reaction mixture is performed. The method comprises forming or obtaining the aqueous reaction mixture having a start viscosity and comprising pol...

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Bibliographische Detailangaben
Hauptverfasser:	KEMPAS, Tomi, KARPPI, Asko, HIETANIEMI, Matti, KONN, Jonas, VANZETTI, Giorgio
Format:	Patent
Sprache:	eng ; fre ; ger
Schlagworte:	CHEMISTRY COMPOSITIONS BASED THEREON IMPREGNATING OR COATING OF PAPER MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS METALLURGY ORGANIC MACROMOLECULAR COMPOUNDS PAPER NOT OTHERWISE PROVIDED FOR PAPER-MAKING PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D PRODUCTION OF CELLULOSE PULP COMPOSITIONS TEXTILES THEIR PREPARATION OR CHEMICAL WORKING-UP TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G
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Beschreibung
Zusammenfassung:	Method for on-site glyoxylation of polyacrylamide in paper mill, board mill or the like is disclosed. Discontinuous batch glyoxylation reaction of aqueous reaction mixture is performed. The method comprises forming or obtaining the aqueous reaction mixture having a start viscosity and comprising polyacrylamide base polymer having weight average molecular weight of 30 000-300 000 g/mol and glyoxal. Concentration of the polyacrylamide base polymer in the reaction mixture is 1.5-8% above a Critical Concentration of the polyacrylamide base polymer. A feed of an alkali is added to the reaction mixture while measuring viscosity of the reaction mixture and/or a process variable related to the viscosity of the reaction mixture and the on-site glyoxylation reaction of polyacrylamide base polymer in the reaction mixture is allowed to proceed. When a predetermined end viscosity value is attained the feed of alkali is ended and acid is added to the reaction mixture.