AMMELINE-MELAMINE-FORMALDEHYDE RESINS - PREPARATION AND PROPERTIES

Ammeline-melamine-formaldehyde resins (AMF Resins) containing 5-100 mo l % of ammeline, were synthesized by polymerization of the preformed s odium salt of ammeline, melamine, and formaldehyde in basic medium by three methods. These resins, when cured, constitute a new class of the rmosets. The rate of hydroxymethylation of the amino groups of the amm eline salt with formaldehyde was somewhat larger then that of the amin o groups on melamine. At higher pH values ammeline insolubility was no t a problem. The AMF resin composition was approximately equal to the mol ratio of the components originally charged. Both ammeline and mela mine were consumed over the entire reaction period. Thus, it is possib le to make approximately uniform random ammeline-melamine-formaldehyde resins (AMF) with any mol ratio of ammeline salt to melamine. By cont rolling the pH of the solution from which the resins were isolated, th e -O- Na+/-OH ratio could be varied. Resin melting points varied widel y with the mol fraction of ammeline and the -O- Na+/-OH ratio. AMF res in solubilities, shelf lives, cloud points, and water tolerance depend ed upon the method of preparation, pH, and other factors. The sodium s alt of ammeline was hydroxymethylated in water more readily than ammel ine. More highly methylolated ammeline species were readily formed in solution but upon precipitation only bis-N-hydroxymethylammeline was i solated. (C) 1996 John Wiley & Sons, Inc.