Preparation of an aqueous suspension of surface-modified nanoparticles of metallic oxides, useful e.g. as UV-absorbers, comprises mixing an aqueous solution of metal salts with an aqueous solution of polymers and heating the mixture

摘要

Preparation of an aqueous suspension of surface-modified nano-particles of a metallic oxide, a metal hydroxide and/or a metallic oxide hydroxide, where the metal is aluminum, magnesium, cerium, iron, titanium, zinc and zirconium, comprises mixing an aqueous solution of a metal salt with an aqueous solution of a polymer at a pH of 3-13 and at a temperature (T1) of 0-50[deg]C and precipitating the surface-modified nanoparticles of the metallic oxide, metal hydroxide and/or the metallic oxide hydroxide by heating the mixture at a temperature (T2) of 60-300[deg]C. Independent claims are included for: (1) a method for the production of a powdered surface-modified nanoparticles of metallic oxide, metal hydroxide and/or metallic oxide hydroxide, comprising mixing an aqueous solution of a metal salt with an aqueous solution of a polymer at a pH value of 3-13 and at a temperature (T1) of 0-50[deg]C, precipitating the surface-modified nano-particle of the metallic oxide, metal hydroxide and/or the metallic oxide hydroxide by heating the mixture at 60-300[deg]C, isolating the precipitated nanoparticles from the aqueous reaction mixture, and drying the nanoparticles; and (2) a powdered surface-modified nanoparticles of a metallic oxide, metal hydroxide, and/or a metallic oxide hydroxide, having a coating with polyasparaginic acid, with a BET surface area of 25-500 m 2/g.