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US 12,528,704 B2Granted
Silica with reduced tribo-charge for toner applications
AssigneeEvonik Operations GmbH
InventorsMareike Giesseler, Frank Menzel, Alexander Lygin, Rainer Golchert
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Abstract
Surface-treated fumed silica, with a tribo-electro static charge of −500 μC/g to +500 μC/g, a ratio of the tribo-electro static charge to BET surface area of −3.5 μC/m2 to +3.5 μC/m2, a methanol wettability of at least 20% by volume methanol in methanol/water mixture, a ratio of carbon content to BET surface area of at most 0.020 wt. %*g/m2, a process for its preparation and the use thereof.
Claims17
Surface treated fumed (pyrogenic) silica, comprising:
- an average primary particle size, d50, of 5 nm to 30 nm;
- a numerical median particle size, d50, of less than 10 μm;
- a tribo-electrostatic charge of −500 μC/g to +500 μC/g;
- a ratio of the tribo-electrostatic charge to BET surface area of −3.5 μC/m2 to +3.5 μC/m2;
- a methanol wettability of at least 20% by volume methanol in a methanol/water mixture;
- and
- a ratio of carbon content to BET surface area of at most 0.020 wt. % x g/m2.
4 more elements
Dependencies are inferred from the claim text.