Process for the Production of an Aerogel Material

Abstract

A process for the production of an aerogel material comprises the following steps: a) preparation of a silicon oxide sol in an alcoholic solvent mixture; b) triggering of the gelation of the sol by adding base, whereby a gel is formed, and optionally aging of the gel; c) hydrophobicization of the optionally aged gel; d) removal of the solvent mixture by subcritical drying, whereby the aerogel material is formed. The silicon oxide sol formed in step a) comprises at least one acid-catalytically activatable hydrophobicization agent, wherein the volume fraction of the hydrophobicization agent in the sol is 5 to 60%. The hydrophobicization in step c) is induced as a result of release or addition of at least one hydrophobicization catalyst acting in combination with the hydrophobicization agent.

1 . A process for the production of an aerogel material, comprising the following steps:
 a) preparation of a silicon oxide sol in an alcoholic solvent mixture;   b) triggering of the gelation of the sol by adding base, whereby a gel is formed, and optionally aging of the gel;   c) hydrophobicization of the optionally aged gel;   d) removal of the solvent mixture by subcritical drying, whereby the aerogel material is formed;
 characterized in that the silicon oxide sol formed in step a) comprises at least one acid-catalytically activatable hydrophobicization agent, where the volume fraction of the hydrophobicization agent in the sol is 5 to 60%, and that the hydrophobicization in step c) is induced as a result of release or addition of at least one hydrophobicization catalyst acting in combination with the hydrophobicization agent. 
   
     
     
         2 . The process according to  claim 1 , wherein the catalytically activatable hydrophobicization agent is hexamethyldisiloxane (HMDSO). 
     
     
         3 . The process according to  claim 1 , wherein the volume fraction of the hydrophobicization agent in the sol is 20 to 50%, in particular 25% to 40% and more particularly 34% to 38%. 
     
     
         4 . The process according to  claim 1 , wherein the hydrophobicization catalyst is formed by a radical decomposition reaction in situ in the gel. 
     
     
         5 . The process according to  claim 1 , wherein the hydrophobicization catalyst is released by slow-release agents in the gel and optionally by thermal activation. 
     
     
         6 . The process according to  claim 1 , wherein the hydrophobicization catalyst is gaseous HCl. 
     
     
         7 . The process according to  claim 1 , wherein the hydrophobicization catalyst is trimethylchlorosilane (TMCS) and/or HCl in an alcoholic solution. 
     
     
         8 . The process according to  claim 1 , wherein the sol further comprises at least one functional silane. 
     
     
         9 . The process according to  claim 1 , wherein the sol further comprises at least one polymerizable monomer. 
     
     
         10 . The process according to  claim 1 , wherein the step c) and optionally an initial phase of step d) are performed at overpressure. 
     
     
         11 . The process according to  claim 1 , wherein the step d) is performed at reduced pressure. 
     
     
         12 . The process according to  claim 1 , wherein the sol is added to a fiber-based matrix after initiation of gelation. 
     
     
         13 . The process according to  claim 1 , wherein at least the steps b) and c) are performed in a continuous process. 
     
     
         14 . Insulant panel, formed from an aerogel material produced according to  claim 1 . 
     
     
         15 . A precursor product for producing an aerogel material, comprising a silicon oxide sol and/or a silicon oxide gel in an alcoholic solvent mixture and at least one acid-catalytically activatable hydrophobicization agent. 
     
     
         16 . The process according to  claim 2 , wherein the volume fraction of the hydrophobicization agent in the sol is 20 to 50%, in particular 25% to 40% and more particularly 34% to 38%. 
     
     
         17 . The process according to  claim 2 , wherein the hydrophobicization catalyst is formed by a radical decomposition reaction in situ in the gel. 
     
     
         18 . The process according to  claim 3 , wherein the hydrophobicization catalyst is formed by a radical decomposition reaction in situ in the gel. 
     
     
         19 . The process according to  claim 2 , wherein hydrophobicization catalyst is released by slow-release agents in the gel and optionally by thermal activation. 
     
     
         20 . The process according to  claim 3 , wherein the hydrophobicization catalyst is released by slow-release agents in the gel and optionally by thermal activation.