Manufacturing method of the aerogel which precipitation of the formation salt occurs in production process, denaturalizes organically

摘要

The present invention relates to a process for the preparation of organically modified aerogels, comprisinga) the preparation of a silicic acid sol having a pH of =4.0 from an aqueous water glass solution, with the aid of at least one organic and/or inorganic acid;b) polycondensation of the resulting silicic acid sol to a SiO2 gel by the addition of a base;c) washing the gel obtained in Step b) with an organic solvent until the water content of the gel is =5% by weight;d) surface-silylating the gel obtained in Step c), ande) drying the surface-silylated gel obtained in Step d), characterized in that at least one acid forms difficultly soluble salts with the cations of the water glass in the silicic acid sol, and that before Step b) the resulting difficultly soluble salts are extensively precipitated and separated from the silicic acid sol.