| 摘要 |
1508103 Heat - curable melamineformaldehyde resin CASSELLA FARBWERKE MAINKUR AG 26 March 1976 [29 March 1975] 12236/76 Heading C3R [Also in Division B5] A heat-curable melamine-formaldehyde resin contains as latent curing agent 0À01 to 2% by weight, relative to solid resin, of a polyphosphoric acid alkyl ester prepared by reacting P2O5 at 30‹ to 120‹ C. with N mols per mol of P2O5 of a dialkyl ether and/or m mols per mol of P2O5 of an alkanol, n+m being at least 0À5 and the alkyl chain length of the alkyl ether and/or alkanol being 1, 2 or 3 carbon atoms, until a sample of the reaction product is completely soluble at 60‹ to 100‹ C. in a C1-4 alkanol or aliphatic chlorohydrocarbon. The melamineformaldehyde resin may have been prepared in the presence of an alkanol, and other modifiers may be included in the precondensation or added subsequently. It is preferred that the melamine-formaldehyde resin be diluted with water and the polyphosphoric acid ester added thereto in the form of a solution in water or a water-miscible organic solvent. The resulting solutions may be used to impregnate papers or fabrics for the manufacture of decorative laminates or for coating wood-based materials. |
