Silicon dioxide dispersion comprising polyol

Abstract

Stable, pourable silicon dioxide dispersion, in which the average, number-related aggregate diameter of the silicon dioxide particles in dispersion is less than 200 nm, and which comprises at least 35 wt. % of a silicon dioxide powder, 3 to 35 wt. % of at least one polyol, 20 to 60 wt. % of water, 0 to 10 wt. % of an additive and a substance having an alkaline action in an amount such that a pH of 10<pH≦12 is established. It can be prepared by a procedure in which silicon dioxide powder is introduced into water and a polyol in a rotor/stator machine, the pH being less than 5, and the mixture is dispersed until the current uptake of the rotor/stator machine is largely constant, and a substance having an alkaline action is subsequently added in an amount such that a pH of the dispersion of 10<pH≦12 results, the substance having an alkaline reaction being added so rapidly that no gel formation takes place. It can be used as a component of a flame-retardant filling of hollow spaces between building components, in particular for insulating glass arrangements.

1 - 13 . (canceled) 
     
     
         14 . A stable, pourable silicon dioxide dispersion, wherein
 the average, number-related aggregate diameter of the silicon dioxide particles in dispersion is less than 200 nm,   said dispersion comprising:
 at least 35 wt. % of silicon dioxide powder, 
 3 to 35 wt. % of at least one polyol, 
 20 to 60 wt. % of water, 
 0 to 10 wt. % of an additive, in each case based on the total amount of the dispersion, and 
 a substance having an alkaline action in an amount so that a pH of 10 21  pH≦12 is established. 
   
     
     
         15 . The stable, pourable silicon dioxide dispersion according to  claim 14 , wherein it comprises no additives. 
     
     
         16 . The stable, pourable silicon dioxide dispersion according to  claim 14 , wherein said silicon dioxide powder is prepared pyrogenically. 
     
     
         17 . The stable, pourable silicon dioxide dispersion according to  claim 16 , wherein the pyrogenically prepared silicon dioxide powder has a specific surface area of 5 to 500 m 2 /g. 
     
     
         18 . The stable, pourable silicon dioxide dispersion according to  claim 14 , wherein said polyol is selected form the group consisting of glycerol, ethylene glycol, trimethylolpropane, pentaerythritol, sorbitol, polyvinyl alcohol, polyethylene glycol and mixtures thereof. 
     
     
         19 . The stable, pourable silicon dioxide dispersion according to  claim 14 , wherein said substance having an alkaline action is selected from the group consisting of alkali metal hydroxides, amines, (alkyl)ammonium hydroxides and/or amino alcohols. 
     
     
         20 . The stable, pourable silicon dioxide dispersion according to  claim 14 , wherein it comprises
 38 to 60 wt. % of pyrogenically prepared silicon dioxide powder having a BET surface area of 30 to 60 m 2 /g,   5 to 25 wt. % of glycerol   25 to 50 wt. % of water and   0.3 to 0.7 wt. % of KOH.   
     
     
         21 . A method of using the silicon dioxide dispersion according to  claim 14  as a component of a flame-retardant filling of hollow spaces between structural components and for transparent insulating glass arrangements.