Process for the preparation of capsules composed of a core of liquid active material surrounded by an inorganic shell

摘要

A process for the preparation of inorganic capsules composed of an aqueous liquid core surrounded by an inorganic shell, the process comprising: i) Emulsifying an aqueous fluid within an organosoluble phase which is immiscible with the aqueous fluid, so as to disperse it therein in the form of aqueous droplets. ii) Bringing into contact, within the emulsion thus obtained, at least one hydrolysable and polycondensable compound of zirconium, of silicon, of aluminium and/or of a transition metal under temperature and pH conditions favourable to the formation of an inorganic precipitate composed of the corresponding oxide or hydroxide. iii) Recovering the inorganic capsules formed, and optionally purifying the capsules, where the formation of the inorganic precipitate in the second stage is carried out in the presence of an amphiphilic surfactant system present in the emulsion and capable of concentrating the deposition of the inorganic particles of the precipitate formed at the interface of the aqueous droplets and of the organosoluble phase and of effectively blocking their diffusion within the droplets.