公开(公告)号：US20240360253A1

公开(公告)日：2024-10-31

申请号：US18688022

申请日：2022-09-21

Applicant: KEMIRA OYJ

Inventor： Asko KARPPI ,  Matti HIETANIEMI ,  Giorgio VANZETTI ,  Jonas KONN ,  Tomi KEMPAS

IPC: C08F8/28 ,  D21H17/45 ,  D21H21/18

CPC classification number: C08F8/28 ,  D21H17/455 ,  D21H21/18 ,  C08F2810/10

Abstract: 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.