Basf Aktiengesellschaft

Ralf Biastoch

Ekkehard Jahns

Gabriele Frank

Peter Neumann

Dieter Hannu Boeckh

Hubert Trauth

Rainer Dyllick-Brenzinger

Werner Bertleff

Birgit Potthoff-Karl

Bernhard Schuler

Matthias Kummer

Thomas Wehlage

Jurgen Krockenberger

Microcapsules of low-formaldehyde melamine/formaldehyde resins

A process for the preparation of microcapsules by the condensation of melamine-formaldehyde resins and/or the methyl ethers thereof in water, in which the substantially water-insoluble material forming the core of the capsule is dispersed, in the presence of an anionic protective colloid at pH's of from 3 to 6.5 by the formation of the microcapsules at temperatures of from 20&deg; to 50&deg; C. followed by curing of the shell of the capsules at from >50&deg; to 100&deg; C., in which, prior to curing, from 10 to 200 wt % of urea, whose amino groups are optionally linked to an ethylene or propylene bridge, based on the melamine-formaldehyde resin are added, the microcapsules produced by this process and also the use thereof in a pressure-sensitive recording system.

Low-formaldehyde dispersion of microcapsules of melamine-formaldehyde resins

The microcapsules containing bleaching agents are obtainable by polymerizing monomer mixtures which comprise

Microcapsules containing bleaching aids

Stabilizer mixture of chroman derivatives and inert organic solvents,

The invention relates to copolymers containing a) 20-90% of 2-acrylamido-2-methylpropanesulfonic acid, sulfoethyl or sulfopropyl (meth) acrylate or vinylsulfonic acid, b) 0-50% of a vinylic acid, c) 0-70% of methyl or ethyl acrylate or methacrylate, C.sub.2 --C.sub.4 -hydroxyalkyl acrylate or N-vinylpyrrolidone and d) 0.1-10% of styrene or C.sub.4 --C.sub.18 -alkyl acrylate or C.sub.4 --C.sub.18 -alkyl methacrylate. The copolymers according to the invention are particularly suitable as protective colloids for microencapsulation.

Cured particle incorporating a cured copolymer protective colloid

Growing community of inventors

Speyer, Germany

Ralf Biastoch