Patent ID: 7563317

Claim:
Silanised, structurally modified, pyrogenically produced silicas, characterised by octylsilyl and/or hexadecylsilyl groups fixed to the surface, wherein structural modification is done by spraying pyrogenically produced silica optionally first with water and then with hexadecyltrimethoxysilane (CH 3 O) 3 SiC 16 H 33 or octyltrimethoxysilane (CH 3 O) 3 SiC 8 H 17 , mixing intensively, mixing for a further 15 to 30 minutes and then tempering at a temperature of 100 to 160° C. for a period of 1 to 3 hours, then structurally modifying said silica by subjecting said silica to a ball mill to produce a silica with a DBP value of at least 10% lower than the DBP value of non-structurally modified silica.