Surface-modified nanoparticles, method for making them and use

Surface-modified nanoparticles (A) made from metal- or semimetal-oxide/hydroxide, where the surface of the nanoparticle is reacted with a modifying agent, which is a polysiloxane compound, under the formation of covalent bond, are new. Surface-modified nano-particles (A), made from metals, semimetal-oxides/hydroxides, where the surface of the nanoparticles are reacted with a modifying agent, which is a polysiloxane compound of formula (R 1> xR 2> 3-xSiR 3>) yR 5>, under the formation of covalent bond, are new. x : 0-2 (preferably 0); y : 1-10 (preferably 2-5); R 1>organic binding residue with 1-18C (preferably 1-3C); R 2>OH or hydrolyzable group such as 1-6C (preferably 1-2C) alkoxy, halo (preferably Cl) or 1-4C (preferably 2C) carboxylic acid; R 3>O or bidentate organic residue such as 1-8C alkyl, alkylene ether, alkylene thioether, alkylene polyether (preferably ethylene oxide, propylene oxide and/or butylene oxide), arylene polyether, alkylene polyesters, or an organic aliphatic, aromatic or araliphatic ester or ether containing urethane or urea groups; and R 5>polybinding organic residue such as polydialkylsiloxane with a number average molecular weight of 300-5000 Daltons, where the alkyl substituent at the silicon atom contains 1-8C. An independent claim is included for a dispersion comprising (A).