Basf Aktiengesellschaft

Badische Anilin- & Soda-fabrik Aktiengesellschaft

Wolfgang Sliwka

Ernst-Heinrich Pommer

August Wigger

Dietrich Hoffmann

Dietrich Schlotterbeck

Dietrich Hoffman

Josef B Pawliczek

Heinz Hartmann

Tilmann Korth

Heinrich Follmann

Otto Atzrott

Karl Kuchner

Wolf-Ruediger Gaefke

Spherical, hard mono- or oligodisperse particles of diameter from 0.1 to 100 .mu.m are prepared by condensation of partially etherified melamine-formaldehyde precondensates which form a clear solution in water in every ratio, in an aqueous solution of a water-soluble polymer which has strongly acid groups and a K value of from 100 to 160, at pH 3 to 6 and at 20.degree. to 100.degree. C., and condensation of the resulting cloudy solution is continued until the precondensate has been consumed, resulting in a dispersion of the particles. The dispersion is neutralized. The particles can be used in the form of the aqueous dispersion or after isolation from the dispersion. The particles are spherical, hard and non-swellable and can be used, for example, as sizes for plastics, polishes, delustrants, extruders and/or as pigment. The process makes it possible to produce particles of predetermined size and size distribution.

Preparation of spherical, hard mono- or oligodisperse particles of

Microcapsules having melamine-formaldehyde precondensate capsule walls are prepared in a continuous process in aqueous dispersion starting from an appropriate melamine-formaldehyde precondensate in the presence of a water-soluble high polymer which contains strongly acid groups by further condensing the water-soluble precondensate until the solution starts to become turbid, then dispersing the material to be encapsulated in the resulting dispersion in the presence of the water-soluble high polymer which contains strongly acid groups and subsequently condensing the wall material of the resulting microcapsules to completion.

Continuous preparation of microcapsules with melamine-formaldehyde

In a process for the preparation of microcapsules based on a melamine-formaldehyde resin, in which the microcapsules are obtained by condensing a melamine-formaldehyde precondensate, its C.sub.1 -C.sub.4 -alkyl ethers, or mixtures thereof, in water in which the material forming the capsule core is dispersed, at a pH of from 3 to 6.5 and at from 20.degree. to 100.degree. C., the improvement that the water contains a homopolymer or copolymer which possesses sulfonic acid groups but is devoid of phenyl or sulfophenyl groups and has a K value of from 100 to 170 or a viscosity of from 200 to 5,000 mPa.s (shearing gradient 489 s.sup.-1 ; 20% strength solution at 25.degree. C.), and that the melamine-formaldehyde precondensate is added continuously, or in portions, in step with the rate of condensation. The process gives individual capsules which are highly impermeable. The capsules are exceptionally useful for the production of pressure-sensitive recording materials.

Process for the preparation of microcapsules, and the microcapsules

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.

Microcapsule-containing wax composition

A process for hardening microcapsules having walls of synthetic polymers containing groups reactive toward aldehyde groups, wherein hardening is effected by means of a methylolmelamine or an ether thereof at a slightly acidic to slightly alkaline pH. Very impermeable microcapsules are obtained, which are suitable for the manufacture of colorless no-carbon papers.

Process for hardening microcapsules

A new valuable fungicide based on N-tridecyl-2,6-dimethylmorpholine as the active ingredient, the said ingredient being in the form of microcapsules of which the wall consists of a polymer while the core contains the active ingredient.

Fungicide

Microcapsules, particularly for the use in the manufacture of 'no carbon required' copying material, which microcapsules contain as core material not only dye precursors but also mono- or poly-alkyl-substituted indans.

Dye-containing microcapsules

A pressure-sensitive copying material consisting of a sheet-like base to which has been applied a coating comprising microcapsules containing dyes. The microcapsules are filled with a solution or suspension of a salt of a dye base and an organic carboxylic acid in an organic water-immiscible solvent. The copying material is distinguished by exceptional non-smudging characteristics and is particularly suitable for the production of business forms.

Growing community of inventors

Weinheim, Germany

Wolfgang Sliwka