Abstract: A method for manufacturing a surface-treated gas-phase-process silica particle, the method including steps of: adding 1,3-divinyl-1,1,3,3-tetramethyldisilazane to a raw material gas-phase-process silica particle and introducing a vinyldimethylsilyl group on a surface of the raw material gas-phase-process silica particle to obtain a preliminarily treated silica particle; and adding hexamethyldisilazane to the preliminarily treated silica particle and introducing a trimethylsilyl group on a surface of the preliminarily treated silica particle to obtain a surface-treated gas-phase-process silica particle.

Abstract: A millable-type silicone rubber composition, including: (A) 100 parts by mass of an organopolysiloxane represented by following average composition formula (1), the organopolysiloxane having polymerization degree of 100 or more, wherein a content of a low molecular siloxane contained as an impurity and having a polymerization degree of 10 or less is less than 1,000 ppm; (B) 5 to 100 parts by mass of a treated silica treated with a vinyl group-containing alkoxysilane and/or a vinyl group-containing organosilazane, the treated silica having a hydrophobicity degree of 40 or more; and (C) an effective amount of a curing agent. This provides a millable-type silicone rubber composition that yields a silicone rubber cured product with: a total of low molecular siloxane components having polymerization degree of 10 or less of less than 1,000 ppm; a small change in plasticity degree of the silicone rubber compound; and a small compression set.

Abstract: A method for manufacturing granulated silica. The method includes granulating silica powders each having a primary particle size of 5 to 50 nm by use of water, and hydrophobizing each surface of the silica powders with a silicon atom-containing hydrophobizing agent before or simultaneously with the granulation step.

Abstract: A method for manufacturing granulated silica. The method includes granulating silica powders each having a primary particle size of 5 to 50 nm by use of water, and hydrophobizing each surface of the silica powders with a silicon atom-containing hydrophobizing agent before or simultaneously with the granulation step.

Abstract: A cellulose nanofiber-supporting inorganic powder includes a cellulose nanofiber and an inorganic powder, wherein the cellulose nanofiber is supported on the inorganic powder. Thus, the cellulose nanofiber may be readily and uniformly dispersed in a resin or rubber composition, and, by adding to the composition, a cellulose nanofiber-supporting inorganic powder is capable of improving the physical properties of a resin or a rubber.

Abstract: The invention provides: an electrostatic image-developing toner external additive including granulated silica which is a granulated material of silica powders each having a primary particle size of 5 to 50 nm and a degree of hydrophobization of 50% or more, the granulated silica having a loose bulk density of 150 g/L or more; and a toner including the electrostatic image-developing toner external additive. These provide an electrostatic image-developing toner external additive excellent in handleability and workability and also capable of improving image quality, and a toner using the external additive.

Abstract: The present invention provides granulated silica including water-granulated silica powders, each of the silica powders having a primary particle size of 5 to 50 nm and a surface hydrophobized with a silicon atom-containing hydrophobizing agent; the granulated silica having a degree of hydrophobization of 40 or more and a loose bulk density of 150 g/L or more. This provides granulated silica that is excellent in handleability and has good dispersibility.

Abstract: A silicon oxide deposit is continuously prepared by feeding a powder feed containing silicon dioxide powder to a reaction chamber, heating the feed at 1,200-1,600° C. to produce a silicon oxide vapor, delivering the vapor to a deposition chamber through a transfer line which is maintained at or above the temperature of the reaction chamber, for thereby causing silicon oxide to deposit on a cool substrate, and removing the silicon oxide deposit from the deposition chamber. Two deposition chambers are provided, and the step of delivering the vapor is alternately switched from one to another deposition chamber.

Abstract: A silicon oxide deposit is continuously prepared by feeding a powder feed containing silicon dioxide powder to a reaction chamber, heating the feed at 1,200-1,600° C. to produce a silicon oxide vapor, delivering the vapor to a deposition chamber through a transfer line which is maintained at or above the temperature of the reaction chamber, for thereby causing silicon oxide to deposit on a cool substrate, and removing the silicon oxide deposit from the deposition chamber. Two deposition chambers are provided, and the step of delivering the vapor is alternately switched from one to another deposition chamber.

Abstract: Particulate silica is prepared by feeding a gas mixture of an organohalosilane gas, a flammable gas capable of generating water vapor when burned, and a free oxygen-containing gas to a reaction chamber through a multiple-tube burner, whereby the organohalosilane is subjected to flame hydrolysis and oxidation reaction. The amount of the flammable gas fed is 0.5-9 mol per mol of the organohalosilane and such that the amount of water vapor resulting from combustion of the flammable gas is 1-6 times the stoichiometric amount, and the gas mixture is fed to the center tube of the burner such that it may have a linear velocity at the outlet of 50-120 m/sec, calculated in the standard state. The resulting silica has a surface area of 100-400 m2/g and a narrow particle size distribution of primary particles and ensures the transparency of silicone rubber filled therewith.

Abstract: Particulate silica is prepared by feeding a gas mixture of an organohalosilane gas, a flammable gas capable of generating water vapor when burned, and a free oxygen-containing gas to a reaction chamber through a multiple-tube burner, whereby the organohalosilane is subjected to flame hydrolysis and oxidation reaction. The amount of the flammable gas fed is 0.5-9 mol per mol of the organohalosilane and such that the amount of water vapor resulting from combustion of the flammable gas is 1-6 times the stoichiometric amount, and the gas mixture is fed to the center tube of the burner such that it may have a linear velocity at the outlet of 50-120 m/sec, calculated in the standard state. The resulting silica has a surface area of 100-400 m2/g and a narrow particle size distribution of primary particles and ensures the transparency of silicone rubber filled therewith.

Abstract: Crude fumed silica resulting from pyrogenic hydrolysis is purified by continuously feeding particulate silica and steam or a mixture of steam and air in a steam/air volume ratio of at least 1/2 through an upright column from its bottom toward its top for forming a fluidized bed within the column at a gas linear velocity of 1 to 10 cm/sec. and a temperature of 250.degree. to 400.degree. C., whereby steam deprives the particulate silica of the halide borne thereon, and removing fine particulate silica from which the halide has been eliminated from the top of the column. Using a simple apparatus, pure fine particulate silica is collected at a low cost of energy consumption.