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US 8,507,033 B2Granted
Surface-modified, pyrogenically prepared silicas
AssigneeEvonik Degussa GmbH
InventorsJuergen Meyer, Mario Scholz, Kai Schumacher
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Abstract
Surface-modified, pyrogenically prepared silica is prepared by subjecting the pyrogenically prepared silica, which is in the form of aggregates of primary particles and possesses a BET surface area of 150±15 m2/g, the aggregates having an average area of 12 000-20 000 nm2, an average equivalent circle diameter (ECD) of 90-120 nm and an average circumference of 1150-1700 nm, to surface-modification in a known way. It can be used as a filler for thickening liquid systems.
Claims9
A process for preparing a silica for incorporation into a resin, the method comprising:
- pyrogenically preparing a silica powder;
- applying at least one dimethylpolysiloxane surface modifier to the pyrogenic silica powder;
- and
- heat treating the silica powder with the applied surface modifier to obtain the silica for incorporation into a resin;
- wherein
- the pyrogenically prepared silica powder comprises aggregates of primary particles,
- a BET surface area of the aggregates is 150±15 m2/g,
- an average area of the aggregates is from 12 000 to 20 000 nm2,
- an average equivalent circle diameter (ECD) of the aggregates is from 90 to 120 nm, and
- an average circumference of the aggregates is from 1150 to 1700 nm.
7 more elements
Dependencies are inferred from the claim text.