초록

The invention relates to a hydrophobic fumed silica which is obtained by grinding a fumed silica which, as a result of silanization, has trimethylsilyl groups fixed on the surface; and to coating formulations comprising this silica.

대표청구항 ▼

1. A ground hydrophobic fumed silica comprising a fumed silica which has trimethylsilyl groups present on the surface, wherein the ground hydrophobic fumed silica has a tamped density of from 10 to 65 g/l;a specific BET surface area of from 210 to 225 m2/g; anda grindometer value of 12 μm or less fo

1. A ground hydrophobic fumed silica comprising a fumed silica which has trimethylsilyl groups present on the surface, wherein the ground hydrophobic fumed silica has a tamped density of from 10 to 65 g/l;a specific BET surface area of from 210 to 225 m2/g; anda grindometer value of 12 μm or less for a dispersion time of 30 minutes or a value of less than 10 μm for a dispersion time of 60 minutes. 2. The silica according to claim 1, wherein the ground hydrophobic fumed silica is obtained by a process comprising grinding fumed silica with a pin mill or an air-jet mill. 3. The silica according to claim 1, which has a mean particle size of from 3.5 to 8.5 μm. 4. The silica according to claim 1, wherein the silica has a pH in the range of 6.5 to 8.0. 5. The silica according to claim 1, which has an agglomerate strength of less than 25 mm. 6. A process for producing the fumed silanized silica according to claim 1, comprising grinding a fumed silica which, as a result of silanization, has trimethylsilyl groups fixed on the surface. 7. The silica according to claim 1, which has a mean particle size of from 3.5 to 8.22 μm. 8. The silica according to claim 1, which has a tamped density of from 17 to 65 g/l. 9. The silica according to claim 1, which has a specific BET surface area of from 216 to 219 m2/g. 10. The silica according to claim 1, which has a tamped density of from 17 to 65 g/l, and a specific BET surface area of from 216 to 219 m2/g. 11. The silica according to claim 1, which has an agglomerate strength of less than 20 mm.