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Use of microcapsules containing UV absorbers in suncare formulations, evaluation of their impact on UV performance and fabric staining reduction 1/13

IP.com Disclosure Number: IPCOM000245990D
Publication Date: 2016-Apr-22

Publishing Venue

The IP.com Prior Art Database

Abstract

The present disclosure relates to the preparation and use of microcapsules comprising a capsule core containing at least one UV absorber and a capsule shell that comprises a core surrounding layer of a polyvinyl alcohol and an adjacent layer of a polyoxazoline for protecting human hair and skin against UV radiation, skin aging and preventing tanning and cosmetic or dermatological compositions comprising these microcapsules.

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Page 01 of 13

Microcapsules containing UV absorbers in suncare formulations, 1/13

Use of microcapsules containing UV absorbers in suncare formulations, evaluation of their

impact on UV performance and fabric staining reduction 1/13

The present disclosure relates to the preparation and use of microcapsules comprising a capsule core containing at least one UV absorber and a capsule shell that comprises a core surrounding layer of a polyvinyl alcohol and an adjacent layer of a polyoxazoline for protecting human hair and skin against UV radiation, skin aging and preventing tanning and cosmetic or dermatological compositions comprising these microcapsules.

According to the well known microencapsulation method of coacervation a water soluble polymer is deposited by phase separation from its solution by the addition of a second solvent reducing its solubility. A well-known system is polyvinylalcohol/-1propanol.

It is further known to produce microcapsules via a complex coacervation method. The shell building process is based on the principle of the neutralization of opposite charged colloids in an aqueous solution. An example for complex coacervation is positively charged gelatin and negatively charged gum arabicum.

The capsule core might be solid or liquid depending on the temperature and the melting point of the core material. Preferred is a capsule core which is liquid at a temperature of 20°C and normal pressure. Liquid means that the core material has a Brookfield viscosity of ≤ 5 Pa.s.

The average particle size of the capsules (Z-average by light scattering) is in the range from
0.5 to 80 μm, preferably in the range from 1 to 50 μm and in particular in the range from 1 to 30 μm, mostly preferred in the range of 1 to 15µm. The weight ratio of capsule core to capsule shell is generally in the range from 50 : 50 to 95 : 5. A core / shell ratio in the range from 70 : 30 to 93 : 7 is preferred. Mostly preferred is a core / shell ratio from 80 : 20 to 88 : 12.

Core materials are preferably selected from the group comprising, preferably consisting
of, aliphatic and aromatic hydrocarbon compounds, saturated or unsaturated C6-

15 C30-fatty acids, fatty alcohols, C6-C30-fatty amines, C4-C30-mono-, C4-C30-di- and C4-C30-polyesters, primary, secondary or tertiary C4-C30-carboxamides, fatty acid esters, natural and synthetic waxes, halogenated hydrocarbons, natural oils, C3-C20-
ketones, C3-C20-aldehydes, fragrances and aroma substances, vitamins and UV filters.

Preferably the UV filters (UV) according to the present invention are oil soluble UV filters.


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Microcapsules containing UV absorbers in suncare formulations, 2/13

Typical oil-soluble UV filters according to the present invention are the following substances (UV1) p-amino benzoic acid derivatives,
(UV 2) salicyl acid derivatives,
(UV 3) benzophenone derivates,
(UV 4) dibenzoylmethane derivatives,
(UV 5) diphenylacrylates,
(UV 6) 3-imidazol-4-yl-acryl acid and their esters;
(UV 7) benzofur...