Fumed silanized silica
View Patent ↗Fumed silanized silica with the following physico-chemical data: Grindometer value less than 20 .mu.m Tamped density 25 to 85 g/l is prepared by grinding fumed silica which has been silanized. It can be used in silicone rubber.
1. Fumed silanized silica having the following physiochemical data:
Grindometer value
less than 20 μm, and
Tamped density
25 to 85 g/l
and obtained in that a fumed silica having the following physiochemical data:
BET surface area m 2 /g:
25-400
average primary particle size nm:
5-50
pH:
3-10
Carbon content %:
0.1-10
is silanized by means of dimethyldichlorosilane and then ground by means of a pinned-disc mill or an air-jet mill.
2. A process for preparing the fumed silanized silica according to claim 1 , comprising silanizing by means of dimethyldichlorosilane a fumed silica having the following physiochemical data:
a BET surface area m 2 /g:
25-400
average primary particle size nm:
5-50
pH:
3-10
Carbon content %:
0.1-10
and then grinding the silanized fumed silica by means of a pinned-disc mill or an air-jet mill to form ground non-reagglomerating silanized fumed silica.
3. Silicon rubber containing as a filler the fumed silanized silica according to claim 1 .