Melamine–formaldehyde curing acceleration by TiO2-based silver-white pigments catalysis

The preparation of melamine–formaldehyde (MF) resins for paper impregnation wood panels laminating was found to be catalyzed by TiO2-mica silver white pigments. presence small proportions those greatly enhances the resin polycondensation during its under same conditions but without These pigments are composed mainly TiO2-mica, as ascertained X-ray diffraction (XRD), with TiO2 being in rutile phase also presenting some traces anatase phase. FTIR and 13C NMR inferred clearly a catalytic effect appeared indicate that involved –NH2 groups melamine on formaldehyde. According peak reaction temperature measured DSC, highest activity MF curing appears achieved at 2% addition level weight. Different possible explanations this have been proposed, most likely one caused TiO2-promoted coordination complexes, acceleration due Ti charge stronger than H+, complex formed unstable, thus not inhibiting progress reaction.