UV filter aqueous microdispersion based on methacrylate copolymer, process of its preparation and cosmetic photoprotective formulation containing such aqueous microdispersion

摘要

In the present invention, there is disclosed an aqueous microdispersion containing microparticles of a copolymer that has been prepared by copolymerization of 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate (of the general formula I) with a smaller amount of a vinyl type reactive comonomer and a cross-linking component. The microdispersion with particle dimensions less than 300 nanometers is prepared by milling the copolymer in a bead mill in the presence of a sulfated oxethylated fatty alcohol, and is intended for the use as UV filter in photoprotective cosmetic formulations. The copolymer microdispersion is characterized by photostability when irradiated by artificial sun radiation. Photoprotective creams containing the microdispersion of the benzotriazole copolymer exhibit high efficiency in filtering-off ultraviolet radiation in UVB as well as in UVA sun spectra. In a mixture with oil-soluble UVB filters, there is indicated a synergy for the increase of sun protective factor SPF.