Abstract: Provided is a novel spherical polymethylsilsesquioxane particle having an unprecedentedly large specific surface area ratio. The spherical polymethylsilsesquioxane particle includes a particle main body containing at least: a network structure formed by silicon atoms (n) and oxygen atoms (n) bonded to the silicon atoms (n); a methyl group bonded to at least one of the silicon atoms (n); and an alkoxyl group bonded to at least one of the silicon atoms (n), wherein the spherical polymethylsilsesquioxane particle satisfies the following expression (1): Expression (1) S1/S2?8.0, in the expression (1), S1 represents a specific surface area (m2/g) measured by a nitrogen adsorption BET one-point method, S2 represents 6/(?×D50) and a unit thereof is (m2/g), ? represents a particle density (g/m3), and D50 represents a volume-based 50% cumulative diameter (m) measured by a laser diffraction/scattering method.

Abstract: Aggregation of metal oxide powder is appropriately reduced. A method for chemical treatment of metal oxide powder (M) includes: a heating step (S10) of introducing the metal oxide powder (M) into a preheated stirring vessel (110) and performing heating while stirring the metal oxide powder (M) with a stirring blade (140); and a mixing step (S20) of adding a chemical agent to the metal oxide powder (M) and mixing the metal oxide powder (M) and the chemical agent while stirring the metal oxide powder (M) and the chemical agent with the stirring blade (140), wherein a rotation speed of the stirring blade (140) is lower in the mixing step (S20) than in the heating step (S10).

Abstract: Provided is a novel spherical polymethylsilsesquioxane particle having an unprecedentedly large specific surface area ratio. The spherical polymethylsilsesquioxane particle includes a particle main body containing at least: a network structure formed by silicon atoms (n) and oxygen atoms (n) bonded to the silicon atoms (n); a methyl group bonded to at least one of the silicon atoms (n); and an alkoxyl group bonded to at least one of the silicon atoms (n), wherein the spherical polymethylsilsesquioxane particle satisfies the following expression (1): Expression (1) S1/S2?8.0, in the expression (1), S1 represents a specific surface area (m2/g) measured by a nitrogen adsorption BET one-point method, S2 represents 6/(?×D50) and a unit thereof is (m2/g), ? represents a particle density (g/m3), and D50 represents a volume-based 50% cumulative diameter (m) measured by a laser diffraction/scattering method.

Abstract: A silicone oil-treated silica particle according to the present invention includes a silica particle body and silicone oil. The silica particle body has a BET specific surface area of 70 m2/g to 120 m2/g. The silica particle body has been surface-treated with the silicone oil. The amount of free silicone oil liberated from the surface of the silica particle body in the silicone oil accounts for 2.0 mass % to 5.0 mass % with respect to the silica particle body. A surface-treated styrene acrylic resin particle, in which 2 parts by mass of the silicone oil-treated silica particle has been added to 100 parts by mass of a styrene acrylic resin particle having a particle size median of 5 ?m to 8 ?m, has a degree of agglomeration of 18% or less.

Abstract: A silicone oil-treated silica particle according to the present invention includes a silica particle body and silicone oil. The silica particle body has a BET specific surface area of 70 m2/g to 120 m2/g. The silica particle body has been surface-treated with the silicone oil. The amount of free silicone oil liberated from the surface of the silica particle body in the silicone oil accounts for 2.0 mass % to 5.0 mass % with respect to the silica particle body. A surface-treated styrene acrylic resin particle, in which 2 parts by mass of the silicone oil-treated silica particle has been added to 100 parts by mass of a styrene acrylic resin particle having a particle size median of 5 ?m to 8 ?m, has a degree of agglomeration of 18 % or less.

Abstract: Provided are a poly alkylsilsesquioxane fine particle having hydrophobicity and having a small particle diameter, an external additive for toner and a dry toner for electrophotography each using the same, and a method of manufacturing a hydrophobized spherical polyalkylsilsesquioxane fine particle. The hydrophobized spherical poly alkylsilsesquioxane fine particle has a mass-based median diameter in a centrifugal sedimentation method within the range of from 0.05 ?m to 0.3 ?m. The fine particle is produced through, for example, at least a process involving: mixing a raw material solution prepared using an alkyl trialkoxysilane with an alkaline aqueous medium to obtain a polycondensation reaction liquid; mixing the polycondensation reaction liquid with an aqueous solution to obtain a fine particle dispersion liquid; and blending a hydrophobizing agent in the fine particle dispersion liquid.

Abstract: Provided are a poly alkylsilsesquioxane fine particle having hydrophobicity and having a small particle diameter, an external additive for toner and a dry toner for electrophotography each using the same, and a method of manufacturing a hydrophobized spherical polyalkylsilsesquioxane fine particle. The hydrophobized spherical poly alkylsilsesquioxane fine particle has a mass-based median diameter in a centrifugal sedimentation method within the range of from 0.05 ?m to 0.3 ?m. The fine particle is produced through, for example, at least a process involving: mixing a raw material solution prepared using an alkyl trialkoxysilane with an alkaline aqueous medium to obtain a polycondensation reaction liquid; mixing the polycondensation reaction liquid with an aqueous solution to obtain a fine particle dispersion liquid; and blending a hydrophobizing agent in the fine particle dispersion liquid.

Abstract: The present invention relates to a method for producing inorganic oxide particles, comprising at least the following steps of: coagulating a dispersion obtained by carrying out the hydrolysis reaction and the polycondensation reaction of a metal alkoxide in the presence of a basic catalyst; filtering the dispersion to obtain particles; and drying the particles, wherein the step of coagulating the dispersion is carried out by adding a coagulant comprising at least one compound selected from the group consisting of carbon dioxide, ammonium carbonate, ammonium hydrogen carbonate and ammonium carbamate to the dispersion. The inorganic oxide particles obtained by the method of the present invention have high purity and are excellent in flowability.

Abstract: The present invention relates to a method for producing inorganic oxide particles, comprising at least the following steps of: coagulating a dispersion obtained by carrying out the hydrolysis reaction and the polycodensation reaction of a metal alkoxide in the presence of a basic catalyst; filtering the dispersion to obtain particles; and drying the particles, wherein the step of coagulating the dispersion is carried out by adding a coagulant comprising at least one compound selected from the group consisting of carbon dioxide, ammonium carbonate, ammonium hydrogen carbonate and ammonium carbamate to the dispersion. The inorganic oxide particles obtained by the method of the present invention have high purity and are excellent in flowability.

Abstract: The present invention relates to a method for producing inorganic oxide particles, comprising at least the following steps of: coagulating a dispersion obtained by carrying out the hydrolysis reaction and the polycondensation reaction of a metal alkoxide in the presence of a basic catalyst; filtering the dispersion to obtain particles; and drying the particles, wherein the step of coagulating the dispersion is carried out by adding a coagulant comprising at least one compound selected from the group consisting of carbon dioxide, ammonium carbonate, ammonium hydrogen carbonate and ammonium carbamate to the dispersion. The inorganic oxide particles obtained by the method of the present invention have high purity and are excellent in flowability.

Abstract: The present invention relates to a method for producing inorganic oxide particles, comprising at least the following steps of: coagulating a dispersion obtained by carrying out the hydrolysis reaction and the polycodensation reaction of a metal alkoxide in the presence of a basic catalyst; filtering the dispersion to obtain particles; and drying the particles, wherein the step of coagulating the dispersion is carried out by adding a coagulant comprising at least one compound selected from the group consisting of carbon dioxide, ammonium carbonate, ammonium hydrogen carbonate and ammonium carbamate to the dispersion. The inorganic oxide particles obtained by the method of the present invention have high purity and are excellent in flowability.