| abstract |
A process for spray drying aqueous suspensions of microcapsules having walls of polyurea which have been formed in known manner from polyisocyanate and polyamine by interface polyaddition, in which from 1 to 10 parts by weight, based on the microcapsules, of a water-soluble silicate and/or a water-soluble alkaline earth metal salt or hydroxide are added to the aqueous reaction mixture of polyisocyanate and polyamine. |