| 摘要 |
A process produces a free flowing, silicic-acid-filled, powdered elastomer wherein the silicic acid employed has the properties set out below: (a) SiO2 content: about 82-91.5% by weight; (b) metallic oxides: about 0.5-3% by weight; (c) loss on ignition (DIN 55 921/2-measured at 100 DEG C.): about 8-15% by weight; (d) moisture (DIN 53 198-measured at 105 DEG C.): about 2-10% by weight; (e) surface area of the primary particles according to BET: about 40-250 m2/g; (f) dibutyl phthalate absorption (ASTM D 2414-79) based on measured weight: about 170-290%. (g) linear average of numerical distribution of secondary particles: about 10-2,000 nm; (h) linear average of volume distribution of secondary particles: about 3-30 um; (i) proportion of secondary particles with a diameter of less than 1 um: about 0.01-5% by weight wherein the percentages of parameters (a) to (c), added up together, must yield 100% by weight. |
