Nippon Aerosil Co., Ltd.

Hirokuni Shirono

Masamichi Murota

Eiji Komai

Takeyoshi Shibasaki

Naruyasu Ishibashi

Toshio Morii

Yuki Amano

Akira Inoue

Hitoshi Kobayashi

Kazuyoshi Honda

Kazuhisa Konno

A fumed-silica, which can make a slurry having sufficient wettability to a polar liquid, excellent dispersibility, and low viscosity even in the high concentration, and a slurry thereof. A fumed-silica and its slurry are provided, wherein the water content is controlled so that a weight loss after drying Y, and a dynamic wetting rate to water Z, have specified values.

Low viscosity-increment fumed-silica and its slurry

The amorphous-silica particle having 0.1&#x2013;0.7 &#x3bc;m of the average particle diameter, 5&#x2013;30 m/g of the specific surface area, less than 40% of the dispersion coefficient, and 20 &#x3bc;C/mof the absolute value of the triboelectrostatic charge, can be obtained, by setting flame temperature to more than melting point of silica, raising the silica concentration in a flame, and staying the generated silica particle in the flame for a short time to be grew up. Since this silica particle has a particle shape being near a true sphere, and a particle size of said particle is remarkably uniform, so it is suitable for a filler of a semiconductor sealing agent or various materials, etc. In addition, since said particle has strong electrification, it is also suitable for an outer or an inner additional agent of a toner for an electronic photograph, a photo conductor material for a electronic photograph, and a material of an electric charge transportation layer, etc.

Amorphous, fine silica particles, and method for their production and their use

A surface modified fine silica powder which has been treated, preferably, with a treating agent containing an amino group, characterized in that the powder exhibits an adsorption amount for an anion source compound of 150% or more of that of an original powder which has not been treated; and a printing material using the silica powder. The surface modified fine silica powder can provide an excellent printed matter being free from blotting with ink or a cracking of coating film.

Surface-modified fine silica powder and use thereof

Regarding the metal oxide fine powder, which is used as the additive of a powder material and is hydrophobic treated on the surface, the peak of the particle size distribution of the agglomerated particle is made to be less than the same level of average size of the powder material, so that said powder has high dispersibility in the powder material. When this metal oxide fine powder is used as the external additive, such as the toner for the electronic photograph, the standup of the electrostatic charge, the image quality, and the cleaning characteristic are improved remarkably.

Fine metal oxide powder having high dispersibility and toner composition comprising the same

Firstly, a powder matrix is kept in a fluent state, said powder matrix consisting of a first oxide having an absorbed water amount of 0.1 to 50%, an averaged particle diameter of 0.005 to 0.5 &mgr;m and a surface hydroxyl group number of 0.1 to 25 &mgr;mol/m . Then, one or both of a halide and an alkoxide including metal or semi-metal identical with or different from the metal or semi-metal constituting said first oxide is allowed to contact with said powder matrix kept in the fluent state, by means of an inert carrier gas, and then they are heated at a temperature of from 25 to 800&deg; C., to thereby coat said powder matrix by a coating layer consisting of a second oxide. Further, a reaction by-product consisting of one or both of a hydrogen halide or an alcohol generated by said contacting is heated at a temperature of from 200 to 1000&deg; C. within the inert carrier gas to thereby eliminate the reaction by-product.

Oxide powder and method for preparing the same, and product using the same

An ultrafine particle silicon dioxide which comprises silicon dioxide powders in the range of ultrafine particles having a BET specific surface area of 350 m /g or more and has a ratio of BET/CTAB specific surface areas of 0.6 to 1.1, a number average of primary particle diameters of 1 to 20 nm, void volume measured with a mercury porosimeter of 0.1 to 1.0 ml/g and linseed oil absorption of 350 to 600 ml/100 g. According to the present invention, the ultrafine particle silicon dioxide can provide various kinds of polymers with excellent mechanical strength and transparency as a filler.

Ultrafine particle silicon dioxide and process for producing the same

A fine powder of hydrophobic titanium oxide, which, when added to toner powder, gives it high flowability and good electrification stability. The titanium oxide is prepared by hydrolyzing a volatile titanium compound while in a high-temperature vapor-phase condition, in the presence of a combustible or incombustible gas, and has a BET specific surface area of from 55 to 150 m,/g and an anatase/rutile crystal structure with a ratio of anatase falling between 0.3 and 0.98. It is processed for surface modification with a silane coupling agent and/or a silicone compound to produce a fine powder of hydrophobic titanium oxide.

Fine powder of hydrophobic titanium oxide, and method for producing it

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.

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Yokkaichi, Japan

Hirokuni Shirono