Method for manufacturing microcapsules containing a lipophilic active ingredient, microcapsules prepared by said method and the use thereof

A process for manufacturing reservoir-type microcapsules, containing a lipophilic active principle in a shell based on at least two covalently bonded polymers forming the wall of said microcapsules, the process comprising the following steps:

• (i) addition to a lipophilic phase, containing at least one active principle, of at least one silane and/or silicate monomer or oligomer, at least one melamine resin and at least one isocyanate, to form a mixture A,
• (ii) dispersion with stirring of the mixture A obtained in step (i) in an aqueous continuous phase B at acidic pH containing at least one gelatin and/or at least one water-soluble plant protein, and at least one polyacid, so as to form, by complex coacervation, an emulsion or a dispersion of droplets of oil-in-water type, enveloped by a coacervate, and to initiate the formation of a first silicone/melamine/polyurethane copolymer enclosing said active principle,
• (iii) optional introduction of a protective colloid such as a cellulose derivative into the aqueous continuous phase containing the dispersion of droplets,
• (iv) addition, to the dispersion of droplets, at a temperature of less than or equal to 10° C., of at least one coacervate-crosslinking agent, enabling the co-crosslinking, at the interface of said droplets, of the gelatin-based and/or plant protein-based coacervate with the first silicone/melamine/polyurethane copolymer undergoing formation, leading to co-crosslinked polymers constituting the wall of said microcapsules and enclosing said active principle,
• (v) production of an aqueous suspension of microcapsules enclosing the lipophilic active principle.