BORON-CONTAINING PRECIPITATED SILICA

摘要

The present invention provides a boron-containing precipitated silica, characterized by the following physical-chemical characteristic data: loss on ignition (DIN 55921) % by weight 14-40 pH value (DIN 53200) 4-6 conductivity in a 4% aqueous dispersion .mu.S <800 tamped powder density (DIN 53194) g/litre 130?100 screenings according to Alpine >63 .mu.m % by weight <0.1 SiO2 content (DIN 55921) but relative to to original substance % by weight 9-76 B2O3 content relative to the original substance % by weight 10-51 Na2O content relative to the original substance % by weight <0.5 SO3 content relative to the original substance % by weight <0.8 The boron-containing precipitated silica is inter alia useful as a filler in materials based on di-organo polysiloxanes hardenable to elastomers.