Coated powders having high photostability

Abstract

A coated powder comprises (a) particles, and (b) a coating on the surface of the particles including (1) silica moieties, (2) organo oxysilane moieties selected from the group consisting of mono-organo oxysilane moieties, bi-organo oxysilane moieties and tri-organo oxysilane moieties, and (3) poly(dialkyl)siloxane moieties. The amount by weight in SiO 2 equivalents of the organo oxysilane moieties and the silica moieties is at least 0.0625% of the total coated powder weight per m 2 /g of the specific surface area of the particle to be coated.

1 . A coated powder, comprising:
 (a) particles, and   (b) a coating, on the surface of the particles, including
 (1) silica moieties, 
 (2) organo oxysilane moieties selected from the group consisting of mono-organo oxysilane moieties, bi-organo oxysilane moieties and tri-organo oxysilane moieties, and 
 (3) poly(dialkyl)siloxane moieties, 
   
       wherein the amount by weight in SiO 2  equivalents of the organo oxysilane moieties and the silica moieties is at least 0.0625% of the total coated powder weight per m 2 /g of the specific surface area of the particle to be coated. 
     
     
         2 . A dispersion, comprising:
 (1) the coated powder of  claim 1 ,   (2) a fluid, and   (3) optionally an antioxidant.   
     
     
         3 . The dispersion of  claim 2 , comprising the antioxidant. 
     
     
         4 . The dispersion of  claim 3 , wherein the antioxidant is selected from the group consisting of vitamins, antioxidant minerals, antioxidant proteins, antioxidant enzymes and coenzymes, phytonutrients and antioxidant hormones. 
     
     
         5 . The dispersion of  claim 3 , wherein the antioxidant is selected from the group consisting of ascorbic acid, tocopherol, green tea extract, hydroxytyrosol and quercetin dehydrate. 
     
     
         6 . (canceled) 
     
     
         7 . The coated powder of  claim 1 , wherein the particles comprise at least one oxide selected from the group consisting of ZnO, TiO 2  and mixtures thereof. 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . The coated powder of  claim 1 , wherein the organo oxysilane moieties each have the formula R 1   n SiO 4-n , with n=1, 2 or 3, and each R 1  group is independently selected from the group consisting of alkyl, alkenyl, alkynyl, aryl and heterocyclic radical. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . The coated powder of  claim 1 , wherein the poly(dialkyl) siloxane moieties each have the formula O(R 2   2 SiO) n (SiR 2   2 )O or O(R 2   2 SiO) n (SiR 2   2 )OR c , where n is an integer of 2 to 14, each R 2  group is an alkyl, and R c  is selected from the group consisting of H, methyl, ethyl and propyl. 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . A process for producing a coated powder, comprising coating particles with a polymer, by polymerizing a composition, comprising
 (i) the particles,   (ii) a first alkoxy silane selected from the group consisting of a tetra-alkoxy silane, a poly(tetra-alkoxy silane) and mixtures thereof,   (iii) an organo alkoxysilane selected from the group consisting of mono-organo alkoxysilane, bi-organo alkoxysilane, tri-organo alkoxysilane and mixtures thereof, and   (iv) a second alkoxy silane selected from the group consisting of a poly(dialkyl)siloxane and mixtures thereof,   wherein the amount by weight in SiO 2  equivalents of the organo oxysilane moieties and the silica moieties is at least 0.0625% of the total coated powder weight per m 2 /g of the specific surface area of the particle to be coated.   
     
     
         17 - 35 . (canceled) 
     
     
         36 . A water-in-oil or oil-in-water emulsion, comprising the coated powder of  claim 1 , and a liquid carrier. 
     
     
         37 - 44 . (canceled) 
     
     
         45 . The dispersion of  claim 2 , further comprising a dispersing aid. 
     
     
         46 - 48 . (canceled) 
     
     
         49 . A coated powder comprising:
 (a) particles, and   (b) a coating, on the surface of the particles, including
 (1) silica moieties, 
 (2) organo oxysilane moieties selected from the group consisting of mono-organo oxysilane moieties, bi-organo oxysilane moieties and tri-organo oxysilane moieties, and 
 (3) poly(dialkyl)siloxane moieties, 
   wherein the coated powder is super-photostable.   
     
     
         50 - 53 . (canceled) 
     
     
         54 . A method of protecting keratinous material comprising coating the keratinous material with a composition comprising the coated powder of  claim 1 . 
     
     
         55 . A method of protecting human skin, comprising coating skin with a composition comprising the coated powder of  claim 1 . 
     
     
         56 . A method of suppressing lipid peroxidation comprising applying to the skin a composition comprising the coated powder of  claim 1 . 
     
     
         57 . A method of preventing or reducing lines and wrinkles on the skin comprising applying to the skin a composition comprising the coated powder of  claim 1 . 
     
     
         58 . A method of preventing loss of elasticity of the skin comprising applying to the skin a composition comprising the coated powder of  claim 1 . 
     
     
         59 . A method of preventing thinning of the skin comprising applying to the skin a composition comprising the coated powder of  claim 1 . 
     
     
         60 - 63 . (canceled) 
     
     
         64 . A method of protecting antioxidants, comprising mixing an antioxidant with the coated powder of  claim 1 . 
     
     
         65 - 90 . (canceled) 
     
     
         91 . The coated powder of  claim 1 , wherein the particles comprise iron oxide.