Water-soluble thermosetting resin and wet-strength agent for paper using the same

摘要

A water-soluble thermosetting resin giving high wet-strength of paper and excellent preservation stability which comprises 20% by weight or less of components having a molecular weight of 10,000 or less; and a water-soluble thermosetting resin giving high wet-strength of paper in which, in a reverse mutation test carried out for the resin as the object to be tested using histidine-requiring Salmonella typhimurium TA1535 strain, the number of reversant colonies generated is less than twice the number of reversant colonies in the solvent control, treated only the solvent as a reference liquid are provided; and a process for producing an aqueous cationic thermosetting resin solution giving excellent preservation stability of the solution which comprises a step of reacting polyamidepolyamine and epihalohydrin, and a step wherein the solution obtained by reacting polyamidepolyamine and epihalohydrin is held at a temperature of about 30 to about 70° C. for a period, while adjusting the pH to about 2 to about 3.8 is also provided.