Epihalohydrin modified dicyandiamide-formaldehyde condensates and process for preparing the same

A process for preparing improved water-soluble thermosettable resinous compositions containing dicyandiamide-formaldehyde condensates which process comprises (1) forming a precondensate solution by refluxing for about 1 to about 4 hours an aqueous mixture of (a) a base reaction product of 1 mole of dicyandiamide, 0.75 mole to 1.5 moles of formaldehyde and an acid salt of a water-soluble polyaminopolyamide in an ammount sufficient to provide from about 0.125 to about 0.5 equivalent of basic nitrogen and (b) an ammonium salt in an amount such that there will be from 0.7 equivalent to about 1.2 equivalents of basic nitrogen derived from the salt of the polyaminopolyamide and the ammonium salt in the aqueous medium, (2) adding to the precondensate solution from 0.30 to 0.45 mole of epihalohydrin per equivalent of basic nitrogen derived from the salt of the polyaminopolyamide and the ammonium salt, and heating the aqueous mixture at about 50.degree. to about 80.degree. C. for about 15 to about 45 minutes until a solution of modified precondensate is formed, (3) adding from about 1.25 to about 3.75 moles of formaldehyde to the aqueous solution of modified precondensate and heating the resulting mixture at about 60.degree. to about 100.degree. C. until the viscosity of an aqueous solution of the resulting reaction product at a solids content of 50% is from about U to Z on the Gardner-Holdt scale, (4) diluting the solution of step (3), if necessary, to a solids content less than 35% and (5) adding to the solution of step (4) from 0.03 to 0.75 mole, per mole of formaldehyde added in step (3), of epihalohydrin or a nitrogen-containing compound of the formula NHRR' where R and R' are independently hydrogen, alkyl or hydroxyalkyl and, where R is hydrogen, R' also is aminoalkyl or an amido group, and heating the resulting mixture at about 45.degree. to about 70.degree. C. for about 0.5 hour to about 2 hours.