Water soluble cationic resin for paper treatment - from melamine, formaldehyde and aliphatic amine, alkanolamine or polyamine

摘要

Water soluble cationic resins useful in wet paper treatment and coatings are prepd. by (a) methylolating melamine with formaldehyde dissolved in methanol in the presence of a primary or secondary aliphatic amine, an alkanolamine or a polyamine, by heating for 0.25-2 hrs. at 60-85 degrees C and pH 7.5-10, (b) effecting a methylation-condensation reaction at pH 5-6, esp. 5.4-5.7, until the min. viscosity is 17 secs., determined at 20 degrees C in an AFNOR cup no. 6, (c) interrupting methylation by addition of an aqs. formaldehyde soln., and (d) continuing condensation for 0.5-2 hrs. at 60-90 degrees C, and pH 5.5-7, esp. 6-6.5. Reproducible prepn. of resins with a good stability and exceptional reactivity. Can be stored for more than one year. Give paper with a very good wet strength.