Method for preparng capsules comprising at least one water-soluble or hydrophilic substance and capsules obtained therefrom

A method for preparing solid microcapsules that comprises of the following steps:

• a) preparing a composition C1, comprising at least one water-soluble or hydrophilic substance dispersed in a hydrophobic phase;
• b) adding, under agitation, of said composition C1 in a polymeric composition C2, the compositions C1 and C2 being immiscible with each other;
• the composition C2 comprising at least one monomer or polymer, at least one crosslinking agent, and optionally at least one photoinitiator or a crosslinking catalyst;
• the viscosity of the composition C2 being comprised between 500 mPa·s and 100 000 mPa·s at 25° C.,
• wherein an emulsion (E1) is obtained comprising droplets of the composition C1 dispersed in the composition C2;
• c) adding, under agitation, of the emulsion (E1) in a composition C3, the compositions C2 and C3 being immiscible with each other;
• the viscosity of the composition C3 being comprised between 500 mPa·s and 100,000 mPa·s at 25° C., and preferably being greater than the viscosity of the emulsion (E1);
• wherein a double emulsion (E2) is obtained comprising droplets dispersed in the composition C3;
• d) applying a shear to the emulsion (E2);
• wherein a double emulsion (E3) is obtained comprising size controlled droplets dispersed in the composition C3;
• and
• e) polymerizing the composition C2, wherein solid microcapsules dispersed in the composition C3 are obtained.