Basf Aktiengesellschaft

Dietrich Hoffman

Wolfgang Sliwka

Herbert Eisermann

Holger Schopke

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&deg; C. and then curing the capsule wall of the preformed microcapsules at >50 to 100&deg; 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.

Low-viscosity, melamine-formaldehyde resin microcapsule dispersions with reduced formaldehyde content

A pressure-sensitive and heat-sensitive recording material which comprises a carrier bearing a color-developing coating consisting of

Pressure-sensitive and heat-sensitive recording material

A microcapsule-containing wax composition, which comprises (a) microcapsules of from 2 to 10 .mu.m diameter, (b) waxes and (c) dispersants, with or without pigments, fillers, volatile constituents and other agents conventionally present in wax compositions for the hot carbon process. The wall material of the microcapsules is a cross-linked urea-melamine condensate. The wax compositions may be applied over all or part of the surface of a base material, and give deeply colored copies with color-forming (CF) layers.

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Roedersheim-Gronau, Germany

Dietrich Hoffman