Acid stabilization and base reactivation of water-soluble wet-strength resins

Claim 1

A PROCESS WHICH COMPRISES (1) REACTING A POLYALKYLENE POLYAMINE HAVING TWO PRIMARY AMINE GROUPS AND AT LEAST ONE SECONDARY AMINE GROUP WITH A DICARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF DIGLYCOLIC ACID AND C3 TO C8 SATURATED ALIPHATIC DICARBOXYLIC ACIDS TO FORM A WATER-SOLUBLE LONG CHAIN POLYAMIMDE CONTAINING SECONDARY AMINE GROUPS, THE MOLE RATIO OF POLYALKYLENE POLYAMINE TO DICARBOXYLIC ACID BEING FROM ABOUT 0.8 TO 1 TO ABOUT 1.4 TO 1, (2) REACTING THE POLYAMIDE IN AQUEOUS SOLUTION WITH EPICHLOROHYDRIN IN A MOLE RATIO OF EPICHLOROHYDRIN TO SECONDARY AMINE GROUPS OF SAID POLYAMIDE OF FROM ABOUT 0.5 TO 1 TO ABOUT 1.8 TO 1 TO FORM AN AQUEOUS SOLUTION OF A WATER-SOLUBLE CATIONIC THERMOSETTING RESIN, (3) REACTING THE RESIN THUS FORMED, IN AQUEOUS SOLUTION, WITH FROM ABOUT 0.3 EQUIVALENT TO ABOUT 1.2 EQUIVALENTS PER EQUIVALENT OF EPICHLOROHYDRIN, OF A WATER-SOLUBLE ACID UNTIL THE EPOXIDE GROUPS ARE CONVERTED SUBSTANTIALLY TO THE CORRESPONDING HAOLOHYDRIN GROUPS.