Water-soluble sulfonated amino-formaldehyde resins. I. Melamine resins,synthesis

The procedure for preparing sulfonated melamine formaldehyde resins and the factors affecting it were investigated. A four-step procedure was developed which results in reproducible watersoluble stable resins. The reactions that take place in the four steps are hydroxymethylation, sulfonation of the methylolmelamine intermediate, low pH condensation, and high pH rearrangement reaction. The reaction and the resins produced were found to be very sensitive to pH, temperature, sulfite/melamine, and formaldehyde/melamine molar ratios. The apparent molecular weight distribution of selected samples was also determined.