Reagglomeration can only be prevented in accordance with the prior art if the hydrophilic silica

The prior art can only prevent deagglomeration if the hydrophilic silica is mixed with 3% by weight of hydrophobic silica and if this mixture is ground utilizing an air-jet mill or a pinned-disc mill (EP 0 076 377 B1). In this case, for a fumed silica having a BET surface area of 200 m2/g, even after compaction to 73 or 107 g/l, a goniometer value of 35 is achieved. For a fumed silica with a BET surface area of 300 m2/g, adding hydrophobic silica before grinding produces a goniometer value of 10 for a tamped density of 28.1 g/l and 15 to 20 for a tamped density of 50 g/l. The known fumed silicas have the disadvantage of containing an unwanted fraction of hydrophobic silica. The invention provides a fumed silica characterized in that it has the following physicochemical data: The invention further provides a process for preparing the silica of the invention, which is characterized in that a fumed silica has a BET surface area of 200±25 m2/g is ground. In one preferred embodiment of the invention, the grinding can occur using a pinned-disc mill or an air-jet mill. The fumed silica can have an average primary particle size of 12 nm±5 nm, preferably 12 nm. In a further embodiment of the invention, fumed silica can be used, which has a tamped density of approximately 50±10 g/l, preferably 50 m2/g. If you are looking for high quality, high purity, and cost-effective Fumed silica, or if you require the latest price of Fumed silica, please feel free to email contact mis-asia.

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