Method for producing hydrophobic heat insulation material

A method for making a structure for insulation comprising

• a) a pulverulent carrier material selected from the group consisting of precipitated silicas, SiO2 aerogels, perlites and mixtures thereof is coated with a liquid silicon compound, wherein the liquid silicon compound has at least one alkyl group and a boiling point of less than 200° C. and wherein coating is performed at a temperature of 0-40° C.;
• b) the pulverulent carrier material that has been coated in step a) with the liquid silicon compound is mixed with a composition comprising a pulverulent hydrophilic fumed silica to form a mixture which is then is subjected to thermal treatment at more than 40° C., thereby forming a thermally treated mixture;
• c) any unreacted liquid silicon compound is subsequently removed from the thermally treated mixture obtained in step b), thus giving the thermally insulating mixture comprising hydrophobic silica;
• and
• d) compacting the thermally insulating mixture comprising hydrophobic silica into a board.