Abstract: An insulating filler composed of a mixed powder in which a hydrophobic fumed oxide powder having an average primary particle size D1, which is smaller than an average primary particle size D2, is adhered to the surface of a magnesium oxide powder and/or a nitride-based inorganic powder having the average primary particle size D2, wherein: the ratio D1/D2 of the average primary particle size D1 to the average primary particle size D2 is 6×10?5 to 3×10?3; the volume resistivity of the mixed powder is 1×1011 ?·m or more; and the content ratio of the hydrophobic fumed oxide powder in the mixed powder is 5-30 mass %. Also provided is an insulating material in which the above-mentioned insulating filler is contained in a resin molded body.

Abstract: An insulating filler composed of a mixed powder in which a hydrophobic fumed oxide powder having an average primary particle size D1, which is smaller than an average primary particle size D2, is adhered to the surface of a magnesium oxide powder and/or a nitride-based inorganic powder having the average primary particle size D2, wherein: the ratio D1/D2 of the average primary particle size D1 to the average primary particle size D2 is 6×10?5 to 3×10?3; the volume resistivity of the mixed powder is 1×1011 ?·m or more; and the content ratio of the hydrophobic fumed oxide powder in the mixed powder is 5-30 mass %. Also provided is an insulating material in which the above-mentioned insulating filler is contained in a resin molded body.

Abstract: Provided is a coating film that can more reliably exhibit an excellent water repellency and an excellent oil repellency. This water- and oil-repellent coating film is a coating film formed on a surface of a material in order to impart water repellency and oil repellency, wherein (1) the coating film contains a metal oxide-containing composite particle; (2) the composite particle contains a) a metal oxide particle and b) a covering layer that contains a polyfluoroalkyl methacrylate resin and is formed on the surface of the metal oxide particle; and (3) a value obtained by dividing the fluorine content (weight %) of the composite particle by a surface area (m2/g) of the metal oxide particle is 0.025 to 0.180.

Abstract: Provided is a coating film that can more reliably exhibit an excellent water repellency and an excellent oil repellency. This water- and oil-repellent coating film is a coating film formed on a surface of a material in order to impart water repellency and oil repellency, wherein (1) the coating film contains a metal oxide-containing composite particle; (2) the composite particle contains a) a metal oxide particle and b) a covering layer that contains a polyfluoroalkyl methacrylate resin and is formed on the surface of the metal oxide particle; and (3) a value obtained by dividing the fluorine content (weight %) of the composite particle by a surface area (m2/g) of the metal oxide particle is 0.025 to 0.180.

Abstract: Provided is a surface-modified metal oxide powder obtained by treating a surface of a metal oxide powder, wherein a ratio (A/B) of an initial triboelectrostatic charge amount (A) at a time of one minute after dispersion of the surface-modified metal oxide powder into a ferrite carrier to a triboelectrostatic charge amount (B) after a lapse of 30 additional minutes is from 1.0 to 2.0, and the triboelectrostatic charge amount (B) is from ?300 to +300 ?C/g. The surface-modified metal oxide powder has a weaker charging property and a better stability over time of a triboelectrostatic charge amount than a conventional one; and thus, when this powder is used as an external additive, various properties including flowability and electrical charging can be stabilized, and in addition, problems such as fogging and image deterioration can be drastically remedied without significantly deteriorating characteristics as a developer and the like.

Abstract: Provided by the present invention is a surface-modified silica powder, characterized in that the said powder is obtained by surface treatment of a silica powder with one or two or more of a compound (A) and with an aminosilane (B), wherein the fixing rate of the compound (A) and the aminosilane (B) is a total of 50% or more, the hydrophobic rate is 80% or more, and the triboelectrostatic charge amount is 200 ?C/g or less in its absolute value. The surface-modified silica powder of the present invention can stabilize many properties including fluidity and electrostatic properties while can significantly reduce problems such as fogging and decrease in image quality without significantly deteriorating characteristics of a developing agent and so forth when this is used as an external additive.

Abstract: Provided by the present invention is a surface-modified silica powder, characterized in that the said powder is obtained by surface treatment of a silica powder with one or two or more of a compound (A) and with an aminosilane (B), wherein the fixing rate of the compound (A) and the aminosilane (B) is a total of 50% or more, the hydrophobic rate is 80% or more, and the triboelectrostatic charge amount is 200 ?C/g or less in its absolute value. The surface-modified silica powder of the present invention can stabilize many properties including fluidity and electrostatic properties while can significantly reduce problems such as fogging and decrease in image quality without significantly deteriorating characteristics of a developing agent and so forth when this is used as an external additive.

Abstract: Provided is a surface-modified metal oxide powder obtained by treating surface of a metal oxide powder, wherein a ratio (A/B) of an initial triboelectrostatic charge amount (A) at the time of one minute after dispersion of the surface-modified metal oxide powder into a ferrite carrier to a triboelectrostatic charge amount (B) with the lapse of 30 minutes in addition is in the range between 1.0 and 2.0, and the triboelectrostatic charge amount (B) after the lapse of time is in the range between ?300 and +300 ?C/g.

Abstract: Provided are silica microparticles having a fine primary particle size suitable for an external toner additive, the microparticles including no bulky agglomerated particles responsible for a decrease in dispersibility into toner and fluidity of toner. The microparticles are capable of preventing detachment from toner, and are superior in effects of imparting uniform dispersibility and fluidity, thereby preventing a white point on printed images from occurring. The silica microparticles are characterized in that the silica microparticles are produced using hexamethyl disilazane or organo-polysiloxane by carrying out hydrophobization of hydrophilic silica microparticles having an average primary particle size of from 20 to 100 nm produced by a gas phase method, and that a ratio of agglomerated particles having a particle size of 1.5 ?m or more is less than a predetermined value by determining using laser diffractometry by a volume-based particle size measurement of the particle.

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: 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.

Abstract: A high concentration silica slurry can be used for polishing of substrates, such as semiconductor materials. The slurry contains a silica powder dispersed in an solvent. The silica slurry has a silica concentration of more than 50% by weight and a viscosity of less than 1000 mPa·s, wherein the silica powder has a ratio DL/DT of less than 1.3, wherein DL is an average particle size of the silica powder measured by a laser diffraction particle size distribution method and DT is an average primary particle size of the silica powder measured by a TEM photography observation, and wherein the silica powder has an average primary particle size of from 0.08 ?m to 0.8 ?m.

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 amorphous-silica particle having 0.1–0.7 ?m of the average particle diameter, 5–30 m2/g of the specific surface area, less than 40% of the dispersion coefficient, and 20 ?C/m2 of 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.

Abstract: 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.

Abstract: [Problem to be Solved]: To provide a surface modified inorganic oxide powder having a reduced amount of residual volatile components. [Solution]: The surface modified inorganic oxide powder is obtained by the surface treatment of an inorganic oxide powder with the use of a treating solution of long-chain alkylsilane and catalysts in a solvent or by the heat treatment of the inorganic oxide powder between the volatilization temperature of the organic volatile components and the decomposition temperature of the treating agents after the surface modification, to reduce the amount of the volatile components to less than 30 ppm, preferably less than 10 ppm.

Abstract: A high concentration silica slurry can be used for polishing of substrates, such as semiconductor materials. The slurry contains a silica powder dispersed in an solvent. The silica slurry has a silica concentration of more than 50% by weight and a viscosity of less than 1000 mPa·s, wherein the silica powder has a ratio DL/DT of less than 1.3, wherein DL is an average particle size of the silica powder measured by a laser diffraction particle size distribution method and DT is an average primary particle size of the silica powder measured by a TEM photography observation, and wherein the silica powder has an average primary particle size of from 0.08 &mgr;m to 0.8 &mgr;m.

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: 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.

Abstract: 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/m2. 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° 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° C. within the inert carrier gas to thereby eliminate the reaction by-product.