Core-composite shell microcapsules
AssigneeFirmenich SA
InventorGregory DARDELLE
Life of this patent
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Abstract
The invention relates to a method for making a core-composite shell microcapsule slurry for the delivery of hydrophobic active ingredients such as fragrance components of perfume oils. The method includes forming an outer shell by coacervation surrounding an internal phase which contains the hydrophobic active ingredient; and forming an inner shell by interfacial polymerization at the interface between the internal phase and the outer shell. The internal phase contains the hydrophobic active ingredient. The microcapsules are typically incorporated in a consumer product wherein the composite shell prevents the hydrophobic active ingredient from release until desired, generally during use of the consumer product.
Claims18
A process for making a core-composite shell microcapsules slurry, which comprises:
- (i) providing as a dispersion in an aqueous vehicle, a hydrophobic internal phase comprising at least one polyisocyanate having at least three isocyanate functional groups and a hydrophobic active ingredient;
- (ii) mixing a first and second polyelectrolytes in the aqueous vehicle under conditions sufficient to form a suspension of complex coacervate nodules;
- (iii) depositing the complex coacervate nodules at an interface of the aqueous vehicle adjacent to the hydrophobic internal phase to form an outer shell of microcapsule, wherein the hydrophobic internal phase forms the core and contains the polyisocyanate and the hydrophobic active ingredient therein;
- and
- (iv) providing conditions sufficient to induce interfacial polymerization of the polyisocyanate inside the outer shell to form an inner shell at the interface between the internal phase and the outer shell to form a core-composite shell microcapsule slurry,
- wherein no amine or polyamine susceptible to polymerize with the polyisocyanate to form the inner shell is added at any stage of the process.
Core-composite shell microcapsules comprising an outer shell of a coacervate, an inner shell consisting essentially of polymerised polyisocyanate formed from at least one polyisocyanate comprising at least three isocyanate functional groups in the absence of a reactant consisting of a polyamine or an amine, and an internal phase comprising an hydrophobic active ingredient, wherein the inner shell and outer shell form a composite structure.
Dependencies are inferred from the claim text.