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EP-3515587-B1 - HYBRID MICROCAPSULES

EP3515587B1EP 3515587 B1EP3515587 B1EP 3515587B1EP-3515587-B1

Inventors

  • WU, Yongtao
  • OUALI, LAHOUSSINE

Dates

Publication Date
20260506
Application Date
20170912

Claims (14)

  1. A process for the preparation of a formaldehyde-free organic-inorganic microcapsule slurry comprising the steps of: 1) suspending in water inorganic particles consisting of non-chemically surface modified inorganic particles to form a water phase; 2) admixing at least one polyisocyanate with a hydrophobic active ingredient-containing oil to form an oil phase; 3) adding the oil phase to the water phase and mixing them to form an oil-in-water Pickering emulsion under conditions allowing the formation of an inorganic-organic microcapsule slurry by interfacial polymerization, said process being characterized in that : - the water phase is free from formaldehyde, and - wherein the non-chemically surface modified inorganic particles have an average diameter greater than 100 nm, as measured by dynamic light scattering, and - wherein the microcapsules are prepared in the absence of any molecular surfactant.
  2. The process according to claim 1, characterized in that the non-chemically surface modified inorganic particles are selected in the group consisting of calcium phosphate, silica, silicates, titanium dioxide, aluminium oxide, zinc oxide, iron oxide, mica, kaolin, montmorillonite, laponite, bentonite, perlite, dolomite, diatomite, vermiculite, hectorite, gibbsite, illite, kaolinite, aluminosilicates, gypsum, bauxite, magnesite, talc, magnesium carbonate, calcium carbonate, diatomaceous earth and mixtures thereof.
  3. The process according to claim 2, characterized in that the non-chemically surface modified inorganic particles comprise, and preferably consist of inorganic particles selected from the group consisting of hydroxyapatite, tricalcium phosphate, kaolin, silica, laponite and mixtures thereof.
  4. The process according to any one of the preceding claims, characterized in that it further comprises a step of dispersing the microcapsule slurry in a solution of monomer or polymer selected from the group consisting of amine, quaternary amines, dopamine, glycidyl ether, polyols, phenols, aminoacids, saccharide, hydrophilic isocyanate and mixtures thereof.
  5. The process according to any one of claims 1 to 4, characterized in that no amine or polyamine is added at any stage of the process.
  6. The process according to any one of the preceding claims, characterized in that the total amount of inorganic particles present in the aqueous phase is comprised between 0.1 and 20 wt%, preferably between 0.2 and 10 wt% of the aqueous phase.
  7. The process according to any one of the preceding claims, characterized in that the hydrophobic active ingredient is selected from the group consisting of a perfume, flavor, nutraceuticals, cosmetics, insect control agents, biocide actives and mixtures thereof, preferably a perfume or a flavor.
  8. A formaldehyde-free organic-inorganic microcapsule slurry obtainable by a process as defined in any one of claims 1 to 7.
  9. A formaldehyde-free organic-inorganic microcapsule powder obtainable by drying the microcapsule slurry as defined in claim 8.
  10. The organic-inorganic microcapsule slurry according to claim 8 including at least one microcapsule comprising a) an oil-based core, preferably comprising a perfume; b) a shell comprising inorganic particles consisting of non-chemically surface modified inorganic particles.
  11. A perfuming composition comprising (i) a microcapsule slurry as defined in claims 8 or 10 or a microcapsule powder as defined in claim 9; (ii) at least one ingredient selected from the group consisting of a perfumery carrier, a perfuming co-ingredient and mixtures thereof; (iii) optionally a solvent or adjuvant.
  12. A liquid consumer product, preferably in the form of a laundry care product, a home care product, a body care product, a skin care product, an air care product, or a hygiene product, said consumer product comprising: a) from 2 to 65% by weight, relative to the total weight of the consumer product, of at least one surfactant; b) water or a water-miscible hydrophilic organic solvent; and c) microcapsules as defined in claims 8 or 10 or a perfuming composition as defined in claim 11.
  13. A liquid consumer product according to claim 12 in the form of a shower gel or a shampoo.
  14. Use of inorganic particles consisting of non-chemically surface modified inorganic particles, for the stabilization of a Pickering emulsion further subjected to an interfacial polymerisation reaction, wherein the non-chemically surface modified inorganic particles have an average diameter greater than 100 nm and wherein the non-chemically surface modified inorganic particles are dispersed in an aqueous phase, wherein the average diameter is measured by dynamic light scattering.

Description

Technical Field The present invention relates to a process for the preparation of organic-inorganic microcapsules (also named hybrid microcapsules), with a hydrophobic active ingredient-based core, preferably a perfume or a flavour, and a polymeric shell comprising inorganic particles consisting of non-chemically surface modified inorganic particles. Microcapsules obtained by said process are also an object of the invention. Perfuming compositions and consumer products comprising said capsules, in particular perfumed consumer products in the form of home care or personal care products, are also part of the invention. Background of the Invention One of the problems faced by the perfumery industry lies in the relatively rapid loss of olfactive benefit provided by odoriferous compounds due to their volatility, particularly that of "top-notes". In order to tailor the release rates of volatiles, delivery systems such as microcapsules containing a perfume, are needed to protect and later release the core payload when triggered. A key requirement from the industry regarding these systems is to survive suspension in challenging bases without physically dissociating or degrading. For instance, fragranced personal and household cleansers containing high levels of aggressive surfactant detergents are very challenging for the stability of microcapsules. Aminoplast microcapsules formed of a melamine-formaldehyde resin have been largely used to encapsulate hydrophobic actives, thus protecting said actives and providing their controlled release. However, capsules such as aminoplast ones suffer from stability problems when used in consumer products comprising surfactants, such as perfumery consumer products, especially after prolonged storage at elevated temperatures. In such products, even though the capsule wall remains intact, the encapsulated active tends to leak out of the capsule by diffusion through the wall due to the presence of surfactants that are able to solubilise the encapsulated active in the product base. The leakage phenomenon reduces the efficiency of the capsules to protect the active and provide its controlled release. A variety of strategies have been described to improve the stability of oil core-based microcapsules. Cross-linking of capsule walls, with chemical groups such as poly(amines) and poly(isocyanates), has been described as a way to improve stability of microcapsules. WO2011/154893 discloses for instance a process for the preparation of polyurea microcapsules using a combination of aromatic and aliphatic polyisocyanates in specific relative concentrations. Stabilization of oil/water interfaces with inorganic particles has been described in so-called Pickering emulsions. In this context, functionalization of inorganic particles to allow their cross-linking is known. For instance, Pickering emulsions cross-linked from an outer water phase with polyelectrolytes providing electrostatic interactions have been the object of prior disclosures (Li Jian et al. in Langmuir (2010), 26(19), 15554-15560). However, such systems are very likely to dissociate in a surfactant base or in ethanol over time as electrostatic interactions are insufficient to promote stability. Covalent cross-linking has also been described in relation with Pickering emulsion in the preparation of colloidosomes. In particular, the use of diisocyanates as cross-linker has been disclosed in scientific publications. WO2009/063257 also describes the use of polyisocyanates as possible cross-linker for surface-modified inorganic particles in order to prepare microcapsules with increased level of protection from UV light for the contents. These products are typically intended for agrochemical applications. This type of system is not suitable for perfume encapsulation. In fact, in order to maintain a good morphology and permeability of the microcapsules, an excess of surface-modified inorganic particles is needed. Another problem is that these microcapsules show little margin for size adjustment. Furthermore, the amount of adsorbed particles at the oil-water interface is limited which affects the properties of the capsule membranes. WO2015091705 discloses a process for the preparation of hybrid organic-inorganic microcapsules, also called "hybrid" microcapsules composed of at least two types of inorganic particles that are cross-linked. More specifically, this document discloses a first type of inorganic particles having at least one amine functionality and a second type of inorganic particles having at least one hydroxyl functionality. The above cited prior art discloses stabilization of oil/water interfaces with chemically surface modified inorganic particles requiring therefore post chemical reaction and/or post chemical treatment to allow their cross-linking. There is therefore a need to provide, in a simple and cost-effective way, stable microcapsules exhibiting good properties such as a high deposition onto surfaces, a low permeabil