NIEDRIGVISKOSE, FORMALDEHYDREDUZIERTE DISPERSIONEN VON MIKROKAPSELN AUS MELAMIN- FORMALDEHYD-HARZEN

Described is a process for preparing a dispersion of microcapsules by condensing a partially methylated melamine-formaldehyde resin having a molar ratio of melamine:formaldehyde:methanol of from 1:3.0:2.0 to 1:6.0:4.0 in water in which the essentially water-insoluble material forming the capsule cor...

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Bibliographische Detailangaben
Hauptverfasser:	EISERMANN, HERBERT, HOFFMANN, DIETRICH
Format:	Patent
Sprache:	ger
Schlagworte:	CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY CHEMISTRY COLOUR PRINTING COMPOSITIONS BASED THEREON COMPOSITIONS OF MACROMOLECULAR COMPOUNDS IMPREGNATING OR COATING OF PAPER LINING MACHINES MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS METALLURGY ORGANIC MACROMOLECULAR COMPOUNDS PAPER NOT OTHERWISE PROVIDED FOR PAPER-MAKING PERFORMING OPERATIONS PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D PRINTING PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES PRODUCTION OF CELLULOSE PULP COMPOSITIONS STAMPS TEXTILES THEIR PREPARATION OR CHEMICAL WORKING-UP THEIR RELEVANT APPARATUS TRANSPORTING TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G TYPEWRITERS
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Beschreibung
Zusammenfassung:	Described is a process for preparing a dispersion of microcapsules by condensing a partially methylated melamine-formaldehyde resin having a molar ratio of melamine:formaldehyde:methanol of from 1:3.0:2.0 to 1:6.0:4.0 in water in which the essentially water-insoluble material forming the capsule core is present in dispersion in the presence of an alkali metal salt of a homopolymer or copolymer of 2-acrylamido-2-methylpropanesulfonic acid as protective colloid at a pH of from 3 to 6.5 by preforming the microcapsules at a temperature of from 20 to 50° C. and then curing the capsule wall of the preformed microcapsules at >50 to 100° C., which comprises adding from 5 to 100% by weight of melamine, based on the melamine-formaldehyde resin, in the course of curing. The microcapsule dispersions are formaldehyde-reduced and of low viscosity.