Formaldehyde → Melamine formaldehyde

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution prepared by dissolving 2.5 parts by weight of 3-diethylamino-7-chlorofluoran in 80 parts by weight of NISSEKI HISOL N-296 (an oil, a trade name, mfd. by Nippon Sekiyu Kagaku K.K.) was emulsified in 100 parts by weight of a 5% aqueous solution of pH 4.0 prepared by dissolving a styrene-maleic anhydride copolymer together with a small amount of sodium hydroxide. On the other hand, when a mixture of 10 parts by weight of melamine, 25 parts by weight of a 37% aqueous formaldehyde solution and 65 parts by weight of water was adjusted to pH 9.0 with sodium hydroxide and heated at 60° C., the mixture became transparent after 15 minutes and a melamine-formaldehyde precondensate was obtained. The precondensate was added to the emulsion obtained above, and the resulting mixture was continuously stirred for 4 hours while maintaining the mixture at 60° C., and then was cooled to room temperature. The solid content of the resulting microcapsule dispersion was 45%.

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