Surface-modified, structurally modified fumed silicas

Abstract

Surface-modified, structurally modified fumed silicas are surface-modified with N-containing silicon compounds.

1 . A surface-modified, structurally modified fumed silica, which has a BET surface area of 200±25 m 2 /g;
 wherein the surface is modified with at least one N-containing silicon selected from the group consisting of aminopropyltriethoxysilane, aminopropyltrimethoxysilane, N(2 aminoethyl)-3 amino-propylmethyldimethoxy-silane and 3 aminopropylmethyldiethoxysilane; and 
 wherein the structural modification is done with mechanical action. 
 
     
     
         2 . A process for preparing the surface-modified, structurally modified fumed silica according to  claim 1 , comprising
 optionally spraying silica with water;   then spraying with the at least one N-containing silicon compound,   then thermally treating the sprayed silica at a temperature of 20 to 400° C. for 0.1 to 6 hours, -and   then structurally modifying the silica via a mechanical action.   
     
     
         3 . A process for preparing the surface-modified, structurally modified silicas according to  claim 1 , comprising treating silica with the at least one N-containing silicon compound, in vapour form; and
 then thermally treating at a temperature of 50 to 800° C. for 0.1 to 6 hours, and   then structurally modifying the silica via a mechanical action.   
     
     
         4 - 5 . (canceled)