Process for the production of microcapsules

A process for the production of microcapsules containing solid or liquid substances, which are sparingly soluble in water, comprising the steps

• (a) continuously mixing material to be encapsulated with a product obtained by the reaction of a diol or a polyol having a molecular weight of from 400 to 10,000 with phosgene, a diisocyanate or a polyisocyanate, said product containing at least two chloroformic acid ester or isocyanate groups per molecule;
• (b) continuously introducing in separate streams into a zone of high turbulence the mixture from step (a), an aqueous phase and a chain lengthening agent, partially or completely dissolved in the aqueous phase, which is at least bifunctional and is an aliphatic, cycloaliphatic or aromatic glycol, an amino glycol or an aliphatic, cycloaliphatic or aromatic amine whereby flow through the zone of high turbulence is at least 300 parts by volume of liquid per unit volume of turbulent zone space per hour;
• (c) maintaining the zone of high turbulence at temperatures from 50.degree. to 150.degree. C. to thereby form a high molecular weight polymer which envelops the substance to be encapsulated and forms microcapsules;
• and
• (d) continuously removing the formed microcapsules from said zone of high turbulence.