Melamine‐formaldehyde resins: I. An examination of some model compound systems

Abstract

AbstractThe possible course of methylotation and subsequent crosslinking steps in melamine‐formaldehyde resins has been investigated by using two model compound systems, viz., 2‐amino‐4, 6‐diphenoxy‐s‐triazine and 2‐amino‐4, 6‐diphenyl‐s‐triazine. The reactions of these models with formaldehyde and the secondary thermally induced condensation reactions have been examined, in particular, by the use of thin‐layer chromatography and by nuclear magnetic resonance and infra‐red spectroscopy. Methylolated products crosslink by forming ether and methylene bridges at ∼120°, the former being readily converted to the latter when the temperature is varied to ∼135°. Ether bridge degradation releases formaldehyde which further reacts in part at available N—H sites. The conversion of ether bridges to methylene bridges is enhanced by the attachment of phenyl groups to the triazine ring.