Abstract: Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 90±15 m2/g, wherein the aggregates display an average surface area of 10000 to 20000 nm2, an average equivalent circle diameter (ECD) of 90 to 130 nm and an average circumference of 1000 to 1400 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1810 to 1890° C. is obtained. Dispersion containing the pyrogenically produced silicon dioxide powder.

Abstract: A high dispersible hydrophobic fine silica powder can be made, wherein the silica powder has hydrophobicity of more than 50%, triboelectrostatic charge of more than ?500 ?C/g, decomposition rate of an organic group on the powder surface of less than 15%, transmittance of a 5% alcoholic dispersion liquid of more than 40% preferably, and a specific surface area of more than 200 m2/g. This high dispersible hydrophobic fine silica powder can be made by mixing a hydrophobic agent comprising a volatile organic silicon compound in the gas state with a fine silica powder in a fluidized bed type reaction vessel at the time of a hydrophobic treatment, and controlling a gas flow rate to more than 5.0 cm/sec at the time of this mixing.

Abstract: Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 300±25 m2/g, wherein the aggregates display an average surface area of 4800 to 6000 nm2, an average equivalent circle diameter (ECD) of 60 to 80 nm and an average circumference of 580 to 750 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a maximum of up to 40 wt. % of a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1390 to 1450° C. is obtained. It can be used as a filler.

Abstract: Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 300±25 m2/g, wherein the aggregates display an average surface area of 4800 to 6000 nm2, an average equivalent circle diameter (ECD) of 60 to 80 nm and an average circumference of 580 to 750 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a maximum of up to 40 wt. % of a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1390 to 1450° C. is obtained. It can be used as a filler.

Abstract: A surface modified inorganic oxide powder is provided, which includes inorganic oxide particles having a surface modified with a mixed solution, which includes an organopoly-siloxane and a silane compound, in the presence of an acid or a base.

Abstract: Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 300±25 m2/g, wherein the aggregates display an average surface area of 4800 to 6000 nm2, an average equivalent circle diameter (ECD) of 60 to 80 nm and an average circumference of 580 to 750 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a maximum of up to 40 wt. % of a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1390 to 1450° C. is obtained. It can be used as a filler.

Abstract: Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 90±15 m2/g, wherein the aggregates display an average surface area of 10000 to 20000 nm2, an average equivalent circle diameter (ECD) of 90 to 130 nm and an average circumference of 1000 to 1400 nm. It is produced by a pyrogenic process in which silicon tetrachloride and a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1810 to 1890° C. is obtained. Dispersion containing the pyrogenically produced silicon dioxide powder.

Abstract: A high dispersible hydrophobic fine silica powder can be made, wherein the silica powder has hydrophobicity of more than 50%, triboelectrostatic charge of more than ?500 ?C/g, decomposition rate of an organic group on the powder surface of less than 15%, transmittance of a 5% alcoholic dispersion liquid of more than 40% preferably, and a specific surface area of more than 200 m2/g. This high dispersible hydrophobic fine silica powder can be made by mixing a hydrophobic agent comprising a volatile organic silicon compound in the gas state with a fine silica powder in a fluidized bed type reaction vessel at the time of a hydrophobic treatment, and controlling a gas flow rate to more than 5.0 cm/sec at the time of this mixing.

Abstract: Glycol starting materials for manufacturing a polyester molded body containing 1 to 20% by weight of dispersed superfine ceramic powder aggregates relative to the total weight of the glycol for enabling polyester molded bodies having a high mechanical strength and transparency to be manufactured. The superfine ceramic powder aggregates dispersed in the glycol starting material have a mean particle size of 0.05 to 0.5 ?m as measured with a laser diffraction particle size distribution analyzer, and wherein the peak indicated in a particle size distribution curve of the superfine ceramic powder aggregates obtained based on the results of the measurement satisfies the relationship of w/h?0.7, wherein h is the peak height and w is the peak width at one half of the peak height (a half-width).

Abstract: A surface modified inorganic oxide powder is provided, which includes inorganic oxide particles having a surface modified with a mixed solution, which includes an organopoly-siloxane and a silane compound, in the presence of an acid or a base.

Abstract: Glycol starting materials for manufacturing a polyester molded body containing 1 to 20% by weight of dispersed superfine ceramic powder aggregates relative to the total weight of the glycol for enabling polyester molded bodies having a high mechanical strength and transparency to be manufactured. The superfine ceramic powder aggregates dispersed in the glycol starting material have a mean particle size of 0.05 to 0.5 &mgr;m as measured with a laser diffraction particle size distribution analyzer, and wherein the peak indicated in a particle size distribution curve of the superfine ceramic powder aggregates obtained based on the results of the measurement satisfies the relationship of w/h≦0.7, wherein h is the peak height and w is the peak width at one half of the peak height (a half-width).

Abstract: The tribo-electro static charge is stabilized by treating the surface of the metallic-oxide fine powders such as a silica powder, using the mixed solution which consists of a specific silane coupling agent containing primary amino group, other silane coupling agent containing amino group and the hydrophobic agent The powder such as silica has the small charge variation with time, and is suitable as the additive of the powder coatings or the electrophotographic toner.

Abstract: A surface modified inorganic oxide powder is provided, which includes inorganic oxide particles having a surface modified with a mixed solution, which includes an organopoly-siloxane and a silane compound, in the presence of an acid or a base.

Abstract: The tribo-electro static charge is stabilized by treating the surface of the metallic-oxide fine powders such as a silica powder, using the mixed solution which consists of a specific silane coupling agent containing primary amino group, other silane coupling agent containing amino group and the hydrophobic agent The powder such as silica has the small charge variation with time, and is suitable as the additive of the powder coatings or the electrophotographic toner.

Abstract: A fine powder of a hydrophobic metal oxide is provided which is produced through surface treatment of fine powder of a metal oxide with an epoxy compound and an alkylsilazane or ammonia thereby ring-opening the epoxy groups in the surface of the fine powder followed by introducing an amino group and an alkylsilyl group, or an amino group into the ring-opened epoxy groups. The fine hydrophobic metal oxide powder has good dispersability, flowability and electrification properties, and has good time-dependent stability. A toner composition for electrophotography that contains the fine hydrophobic metal oxide powder has stable and good imaging capabilities for a long period of time. Also provided is a method for modifying the surface of the fine metal oxide powder with a surface modifier, in which ammonia is introduced into the reaction system prior to the treatment of the fine powder with the surface modifier.