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Resins obtained by a chemical reaction between melamine and formaldehyde due to
addition and/or condensation mechanisms, acid- or basic-catalyzed have found a widespread
application as components in various formulations of coatings, impregnating
media and adhesives. The appropriate chemical industry offers a variety of different
products which like in other fields of resin chemistry are more defined by their synthetic
pathway, their special features and by their. cure pejformance rather than by a chemical
formula, although usually there is no classical chain reaction taking place as with typical
polymer forming processes. Dependent on their proposed application these resins exhibit
a different cure response, a varying range of the average molecular mass, sometimes
even a rather limited stability. But because of their low and stable price and since
the performance of the cured formulations remains apparently quite reproducible there
is no evidence of replacing these resins,in near future by a product of a comparable behaviour
and quality. There has been placed a remarkable emphasis upon the cure
chemistry of these resins and as a result significant relations have been discovered
between the characteristic features of the resins themselves and the cure conditions
despite major differences concerning the coreactants and catalysts.
Essential for our work are those investigations dealing with melamine formaldehyde
resins (MF) as preferred crosslinking agents in formulations containing polymers which
comprise reactive sites capable to react with partially or fully alkylated methylol groups.
Meanwhile besides the feature of the MF itself the formation of crosslinks by MF has
been discovered to be a complex function of the type and structure of the polymer partner,
the cure schedule, time and temperature, the catalyst etc. Sometimes researchers
even draw quite contrary conclusions from their results which gives an indication on the
difficulties concerned with the theoretical evaluation of the data achieved. Successful
approaches were made to predict the cure behaviour of formulations by comprehensive
analytical methods and calculations thereof (1,2).
