Particulate uv protection agent

Abstract

The present invention relates to particulate UV protection agents which are obtainable by hydrothermal treatment of a particulate metal oxide and subsequent application of a manganese oxide coating, and to the preparation and use thereof. The present invention furthermore relates to novel compositions, in particular for topical application, which are intended, in particular, for light protection of the skin and/or hair against UV radiation and free-radical-induced stress, and to the use thereof in the above-mentioned cosmetic application.

1 . UV protection agent, where the UV protection essentially emanates from a particulate metal oxide, characterised in that the metal oxide has a manganese-containing coating. 
   
   
       2 . UV protection agent according to  claim 1 , characterised in that the metal oxide carries at least one coating, where the at least one coating is preferably a silicon dioxide, manganese dioxide, cerium oxide or aluminium oxide or silicon hydroxide, manganese hydroxide, cerium hydroxide or aluminium hydroxide coating, or a mixture thereof. 
   
   
       3 . UV protection agent according to  claim 1 , characterised in that it is obtainable by hydrothermal treatment of the particulate metal oxide and subsequent application of at least one coating. 
   
   
       4 . UV protection agent according to  claim 1 , characterised in that the metal oxide is essentially titanium dioxide, which may optionally be doped with metal ions, such as, in particular, iron or cerium ions. 
   
   
       5 . UV protection agent according to  claim 1 , characterised in that the crystallite size of the particulate metal oxide in the particulate UV protection agent, determined by the Scherrer method, is in the range from 5 nm to 100 nm, preferably in the range 8 to 50 nm and particularly preferably below 25 nm, and the dimensions of the particulate metal oxide, which can be determined in a transmission electron microscope, are a length of 5 to 150 nm and a width of 5 to 60 nm, preferably a length in the range from 20 to 60 nm and a width in the range from 8 to 30 nm. 
   
   
       6 . UV protection agent according to  claim 1 , characterised in that the at least one coating makes up 5 to 50% by weight, preferably 8 to 30% by weight and particularly preferably 12 to 20% by weight, based on the particulate UV protection agent. 
   
   
       7 . UV protection agent according to  claim 1 , characterised in that the particulate UV protection agent has a particle size, determined by the Scherrer method, in the range from 5 nm to 100 nm, preferably in the range 8 to 50 nm and particularly preferably below 25 nm, and the dimensions of the particulate UV protection agent, which can be determined in a transmission electron microscope, are a length of 10 to 160 nm and a width of 5 to 70 nm, preferably a length in the range from 30 to 70 nm and a width in the range from 7 to 40 nm. 
   
   
       8 . UV protection agent according to  claim 1 , characterised in that the decadic absorption coefficient of a surface coating comprising the UV protection agent at 300 nm is greater than 30, preferably greater than 35 and particularly preferably greater than 40. 
   
   
       9 . UV protection agent according to  claim 1 , characterised in that the decadic absorption coefficient of a surface coating comprising the UV protection agent at 560 nm is less than 1. 
   
   
       10 . UV protection agent according to  claim 1 , characterised in that the metal oxide parent substance carries a first coating essentially consisting of manganese compounds and a second coating essentially consisting of aluminium and/or silicon compounds. 
   
   
       11 . UV protection agent according to one or more of  claim 1 , characterised in that the metal oxide parent substance carries a first coating essentially consisting of aluminium and/or silicon compounds and a second coating essentially consisting of manganese compounds. 
   
   
       12 . UV protection agent according to  claim 1 , characterised in that the metal oxide parent substance carries a coating essentially consisting of a mixture of manganese compounds with aluminium and/or silicon compounds. 
   
   
       13 . UV protection agent according to  claim 1 , characterised in that the manganese compound(s) is (are) selected from the oxides, hydroxides, phosphates, sulfates and fatty acid salts of manganese. 
   
   
       14 . UV protection agent according to  claim 1 , characterised in that the outer layer is a hydrophobicising layer. 
   
   
       15 . Process for the preparation of a particulate UV protection agent, characterised in that
 a) a particulate metal oxide is subjected to hydrothermal treatment and   b) a manganese-containing coating is subsequently applied.   
   
   
       16 . Process according to  claim 15 , characterised in that a particulate titanium dioxide is hydrothermally treated in step a). 
   
   
       17 . Process according to  claim 15 , characterised in that step a) is carried out in a sealed container at temperatures in the range from 40 to 360° C., preferably in the range from 80 to 220° C. and particularly preferably in the range from 140 to 200° C. 
   
   
       18 . Process according to  claim 15 , characterised in that step b) is carried out as a sol-gel process, in which a manganese sulfate solution is preferably added to a suspension of the metal oxide. 
   
   
       19 . Process according to  claim 15 , characterised in that step b) is carried out at a pH kept constant in the range from pH=2 to pH=11, preferably in the range from pH=5 to pH=8, particularly preferably in the range from pH=6 to pH=7. 
   
   
       20 . Process according to  claim 15 , characterised in that step b) is carried out at elevated temperature, preferably at a temperature in the range from 50° C. to 100° C. 
   
   
       21 . Process according to  claim 15 , characterised in that a hydrophobicising layer is applied in an aftertreatment. 
   
   
       22 . Aqueous or oily dispersion comprising a particulate UV protection agent according to  claim 1 . 
   
   
       23 . Composition having light-protection properties comprising at least one UV protection agent according to  claim 1  or a particulate metal oxide prepared by a process wherein
 a) a particulate metal oxide is subjected to hydrothermal treatment and   b) a manganese-containing coating is subsequently applied.   
   
   
       24 . Composition having light-protection properties according to  claim 23 , characterised in that it is a composition which can be applied topically, preferably a cosmetic or dermatological formulation. 
   
   
       25 . Composition having light-protection properties according to  claim 23 , characterised in that it is a composition selected from the group of fibres, textiles, including coatings thereof, paints, coating systems, films and packaging for the protection of foods, plants or industrial products. 
   
   
       26 . Composition having light-protection properties according to  claim 23 , characterised in that the composition comprises at least one organic UV filter, preferably a dibenzoylmethane derivative, in particular methoxy-tert-butyldibenzoylmethane, and/or a benzophenone derivative, such as 2-hydroxy-4-methoxybenzophenone. 
   
   
       27 . Composition having light-protection properties according to  claim 23 , characterised in that the composition comprises at least one self-tanning agent, preferably dihydroxyacetone or a dihydroxyacetone derivative. 
   
   
       28 . Composition having light-protection properties according to  claim 23 , characterised in that the composition comprises at least one photostabiliser, preferably conforming to the formula III 
     
       
         
         
             
             
         
       
     
     where
 R 1  is selected from —C(O)CH 3 , —CO 2 R 3 , —C(O)NH 2  and —C(O)N(R 4 ) 2 ; 
 X is O or NH; 
 R 2  stands for a linear or branched C 1-30 -alkyl radical; 
 R 3  stands for a linear or branched C 1-20 -alkyl radical; 
 all R 4 , independently of one another, stand for H or linear or branched C 1-8 -alkyl radicals; 
 R 5  stands for H, a linear or branched C 1-8 -alkyl radical or a linear or branched —O—C 1-8 -alkyl radical; and 
 R 6  stands for a C 1-8 -alkyl radical; 
 where the photostabiliser is particularly preferably bis(2-ethylhexyl) 2-(4-hydroxy-3,5-dimethoxybenzylidene)malonate. 
 
   
   
       29 . Composition having light-protection properties according to  claim 23 , characterised in that the composition comprises one or more further UV filters, which are preferably selected from the group comprising 3-(4′-methylbenzylidene)-dl-camphor, octyl methoxycinnamate, 3,3,5-trimethylcyclohexyl salicylate, 2-ethylhexyl 4-(dimethylamino)benzoate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-phenylbenzimidazole-5-sulfonic acid and the potassium, sodium and triethanolamine salts thereof. 
   
   
       30 . Composition having light-protection properties according to  claim 23  suitable for the protection of body cells against oxidative stress, in particular for reducing skin ageing, characterised in that it preferably comprises one or more antioxidants. 
   
   
       31 . Composition having light-protection properties according to  claim 23 , characterised in that it is an emulsifier-free emulsion, preferably a Pickering emulsion. 
   
   
       32 . Process for the preparation of a composition according to  claim 23 , characterised in that a corresponding particulate UV protection agent or a particulate UV protection agent prepared according to the above is mixed with a cosmetically or dermatologically suitable vehicle and optionally further ingredients. 
   
   
       33 . (canceled) 
   
   
       34 . UV filter comprising a particulate UV protection agent according to  claim 1  or a particulate UV protection agent prepared by a process wherein
 a) a particulate metal oxide is subjected to hydrothermal treatment and   b) a manganese-containing coating is subsequently applied.   
   
   
       35 . A method for the stabilisation of self-tanning agents, in particular dihydroxyacetone and derivatives of dihydroxyacetone, comprising formulating with
 a) a particulate metal oxide is subjected to hydrothermal treatment and   b) a manganese-containing coating is subsequently applied.   
   
   
       36 . A method of UV protection in paints, coating systems, films, packaging, fibres, textiles and rubber or silicone rubber mouldings, such as tyres or insulators, comprising formulating with
 a) a particulate metal oxide is subjected to hydrothermal treatment and   b) a manganese-containing coating is subsequently applied.