Formaldehyde → Melamine formaldehyde

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A hydrophobic material was prepared by dissolving under heating 2 gr of crystal violet lactone (CVL) and 1 gr of benzoyl leucomethylene blue (BLMB) in 100 gr of KMC-113 (commercial name for an oil product--an aromatic hydrocarbon solvent mainly composed of diisopropylnaphthalene, b.p. 250°-350° C. - by Kureha Chemicals), and this hydrophobic material (an oil solution of dye) was emulsified in 100 gr of a 5% aqueous solution (pH 4.0) of Scripset 520 (a styrene-maleic anhydride (1:1 by mole) copolymer by Monsanto) having dissolved therein a small quantity of sodium hydroxide. Then, a mixture composed of 10 gr of melamine, 25 gr of 37% formaldehyde and 65 gr of water was rendered into pH 9 with sodium hydroxide and heated to 60° C., whereby the solution became transparent in 15 minutes and a melamine-formaldehyde precondensate was obtained. To this precondensate was added the said emulsion, and after adjusting the solution temperature to 60° C., the mixture was agitated. Formation of the capsules was confirmed in 30 minutes, so that products were cooled down to room temperature. The thus obtained micro-capsules could be excellently applied to no-carbon copying paper. (See the photograph of FIGURE).

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