To provide a method for producing an aqueous polyamide-polyamine-epihalohydrin-based cationic thermosetting resin solution which has ability to enhance wet strength and excellent long-term storage stability.
The method for producing the aqueous cationic thermosetting resin solution includes reacting (C) epihalohydrin with an aqueous polyamide-polyamine solution, obtained by reacting (A) an aliphatic dicarboxylic acid-based compound and (B) a polyalkylene polyamine. In the method, (1) the (C) epihalohydrin is added to the aqueous polyamide-polyamine solution and a reaction is performed at a temperature of 10-45and a reactant concentration of 35-70 wt.% (primary heat insulation), (2) the reaction system is then kept at a temperature of 35-70 C after adding water or without adding water at a reactant concentration of 35-45 wt.% (secondary heat insulation), and (3) the reaction system is further kept at a temperature of 30-50 C lower than the temperature in the secondary heat insulation after adding water or without adding water at a reactant concentration of 35-45 wt.% (tertiary heat insulation).
MATSUMOTO KOJI
HAMAGUCHI TOSHISHIGE
