METHOD FOR IMPROVING THE WET STRENGTH PROPERTIES OF RESINS BY ACTIVATING A BASE Russian patent published in 2019 - IPC D21H21/20 D21H17/46 D21H17/52 D21H17/55 D21H17/56 C08G73/02 

FIELD: textile and paper.

SUBSTANCE: invention relates to polyaminopolyamide-epihalohydrin resin and use thereof in making paper. Method of making paper involves obtaining an aqueous solution of resin, imparting strength in wet condition, having reduced specific viscosity (RSV) of less than 0.25 dl/(g dry substance), selected from a group comprising polyaminopolyamide-epihalohydrin resins, polyalkylene polyamine-epihalohydrin resins and their mixture. Then aqueous solution is treated with base to provide pH 13–11 at temperature 30–60 °C for 20 minutes – 4 hours. Resulting resin has value of RSV more than 0.35 dl/g, and not less than 95 % contained in initial resin of tertiary aminohalohydrin is converted into epoxides. Then, the treated resin is added to the composition for making paper.

EFFECT: higher strength of paper in wet condition and higher ratio of strength in wet condition to strength in dry condition.

17 cl, 2 dwg, 8 tbl, 7 ex