Pyrogenically prepared, surface modified aluminum oxide
View Patent ↗Pyrogenically prepared, surface modified aluminum oxide, having the following physical chemical properties: Surface area [m 2 /g] 50 to 150 Tamped density [g/L] 25 to 130 Drying loss [%] less than 5 Loss on ignition [%] 0.1 to 15 C content [%] 0.1 to 15 pH value 3 to 9 is prepared by treating pyrogenically prepared aluminum oxide with a surface modifying agent.
1. A product consisting of a pyrogenically prepared, surface modified aluminum oxide modified by a surface modifying agent selected from the group consisting of octyltrimethoxysilane and octyltriethoxysilane, and having the following physical chemical properties:
Surface area [m 2 /g]
50 to 150
Tamped density [g/L]
25 to 130
Drying loss [%]
less than 5
Loss on ignition [%]
0.1 to 15
C content [%]
0.1 to 15
pH value
3 to 9.
2. A corona resistant polymer composition comprising a filled thermosetting or thermoplastic polymer having dispersed within said polymer as a filler an additive consisting of the product according to claim 1 .
3. The corona resistant polymer composition according to claim 2 wherein the polymer is a polyimide.
4. A shaped article made from the polymer composition according to claim 2 .
5. A process for the preparation of the product in accordance with claim 1 , comprising spraying the pyrogenically prepared aluminum oxide with the surface modifying agent at room temperature to form a mixture and subsequently thermally treating the mixture at a temperature of 50 to 400° C. over a period of 1 to 6 h.
6. A process for the preparation of the product in accordance with claim 1 , comprising spraying the pyrogenically prepared aluminum oxide with the surface modifying agent in vapor form and to form a mixture subsequently thermally treating the mixture at a temperature of 50 to 800° C. over a period of 0.5 to 6 h.