Patent ID: 6710091
Filing Date: 2004-03-23
Classification: B82Y,C01G,C08K

Abstract:
Process for the preparation of nano size zinc oxide particles, which are redispersible in organic solvents and/or water, comprisinga) carrying out basic hydrolysis of at least one zinc compound in alcohol or an alcohol/water mixture, wherein the hydrolysis is carried out with substoichiometric amounts of base, based on the zinc compound, to form a precipitate; b) leaving the precipitate which initially forms during hydrolysis to mature until the zinc oxide has completely flocculated, c) thickening the precipitate to give a gel; and d) separating the gel from the supernatant phase; wherein the gel comprises nano sized zinc oxide particles having an average primary particle diameter of <15 nm, determined in a transmission electron micrograph.