IN-SITE GLYOXYLATION METHOD OF POLYACRYLAMIT AND A WATER-BASED REACTION MIXTURE INCLUDING POLYACRYLAMIT-BASED POLYMER AND GLYOXAL IN THIS METHOD

Abstract

The invention relates to a method for the glycation of polyacrylamide in a paper mill, cardboard mill or similar, wherein the discontinuous glycation reaction of an aqueous reaction mixture is carried out in a reaction vessel equipped with a driven stirrer to produce a glycated polyacrylamide aqueous polymer product for use in the production of paper, cardboard or similar. The method consists of the following steps: the creation or collection of an aqueous reaction mixture consisting of polyacrylamide and glyoxal-based polyacrylamide, the determination of the alkali consumption of the reaction mixture, and the addition to the reaction mixture, on the basis of the determined alkali consumption, of a predetermined amount of alkali such that it is necessary to adjust the pH value of the reaction mixture to be between 8 and 10, preferably between 8.5 and 9.5.The temperature of the reaction mixture is arbitrarily adjusted to a range of 15 to 40°C, further to 20 to 30°C, and the in-situ glyoxylation of the polyacrylamide-based polymer in the reaction mixture is permitted. The viscosity of the reaction mixture and / or process variables related to the viscosity of the reaction mixture are measured. Acid is added to the reaction mixture to reduce the pH value of the reaction mixture to <8, preferably <7. Once a predetermined final viscosity value is achieved, the aqueous polymer product containing glyoxylated polyacrylamide is removed from the reaction vessel. The invention also relates to an aqueous reaction mixture comprising polyacrylamide-based polymer and glycal suitable for use in the above method.