Abstract: Provided are titanium oxide fine particles which are excellent in transparency and are less photocatalytically active while maintaining a high refractive index, a dispersion of such fine particles, and a method for producing such a dispersion. The method for producing a dispersion of iron-containing rutile titanium oxide fine particles including a step (1) of neutralizing an aqueous metal mineral acid salt solution containing Ti and Fe in Fe2O3/(TiO2+Fe2O3)=0.001 to 0.010 to form an iron-containing hydrous titanic acid; a step (2) of adding an aqueous hydrogen peroxide solution to form an aqueous solution of iron-containing peroxotitanic acid having an average particle size of 15 to 50 nm; a step (3) of adding a tin compound so as to satisfy TiO2/SnO2=6 to 16; a step (4) of adding a sol of silica-based fine particles which contain Si and a metal element M in SiO2/MOx/2=99.9/0.1 to 80/20, the addition being made so as to satisfy SiO2/(oxides of the other elements)=0.08 to 0.

Abstract: Provided are titanium oxide fine particles which are excellent in transparency and are less photocatalytically active while maintaining a high refractive index, a dispersion of such fine particles, and a method for producing such a dispersion. The method for producing a dispersion of iron-containing rutile titanium oxide fine particles including a step (1) of neutralizing an aqueous metal mineral acid salt solution containing Ti and Fe in Fe2O3/(TiO2+Fe2O3)=0.001 to 0.010 to form an iron-containing hydrous titanic acid; a step (2) of adding an aqueous hydrogen peroxide solution to form an aqueous solution of iron-containing peroxotitanic acid having an average particle size of 15 to 50 nm; a step (3) of adding a tin compound so as to satisfy TiO2/SnO2=6 to 16; a step (4) of adding a sol of silica-based fine particles which contain Si and a metal element M in SiO2/MOx/2=99.9/0.1 to 80/20, the addition being made so as to satisfy SiO2/(oxides of the other elements)=0.08 to 0.

Abstract: Provided is a method for producing a zirconia-coated titanium oxide fine particle dispersion which includes (1) a step of preparing a dispersion (1) of titanium oxide fine particles, (2) a step of adding, to the dispersion (1), 1 to 50 parts by mass of an aqueous peroxozirconic acid solution in terms of the mass of ZrO2 per 100 parts by mass of the titanium oxide fine particles, and then aging reaction fine particles (2a) obtained as a result of a reaction between the titanium oxide fine particles and the peroxozirconic acid to thereby obtain a dispersion (2) of a zirconia-coated titanium oxide fine particle precursor (2b), and (3) a step of adjusting the dispersion (2) to have a solid concentration of 0.01 to 10 mass % and then hydrothermally treating the resulting dispersion (2).

Abstract: There is provided a production method of a chain silica particle dispersion. This production method includes a dispersion preparation step of hydrolyzing alkoxysilane in the presence of ammonia to prepare a silica particle dispersion, an ammonia removal step of removing the ammonia from the silica particle dispersion such that an ammonia amount relative to silica contained in the silica particle dispersion is 0.3% by mass or less, and a hydrothermal treatment step of hydrothermally treating the silica particle dispersion having a silica concentration of 12% by mass or more, from which the ammonia has been removed, at a temperature of not lower than 150° C. and lower than 250° C. An abrasive including such chain silica particles is high in polishing rate and excellent in polishing properties.

Abstract: Provided is a production method of a silica particle dispersion liquid which includes, preparing a linked silica particle by adding a liquid A containing alkoxysilane and a liquid B containing an alkali catalyst to a liquid containing water, an organic solvent, and an alkali catalyst in a container. The preparing a linked silica particle includes initially adding an alkali catalyst, the initially adding an alkali catalyst includes decreasing a molar ratio of an alkali catalyst to silica in the liquid in the container to 0.15 to 0.60 by adding the liquid A containing alkoxysilane to the liquid in the container, and increasing the molar ratio by 0.2 or more by adding the liquid B to the liquid having the decreased molar ratio in the container.

Abstract: A polishing composition that can not only achieve high polishing speed, but also can improve the surface smoothness (surface quality) of a polished substrate and reduce defects is provided. That is, provided is a polishing composition comprising silica particles and a water soluble polymer, wherein the contained silica particles satisfy the following requirements (a) to (c): (a) the primary particle diameter based on the specific surface area is 5 to 300 nm; (b) the coefficient of variation in the particle diameter is 10% or less; and (c) the Sears number Y is 10.0 to 12.0.

Abstract: Provided is a dispersion liquid of silica particles, comprising silica particles having an average particle diameter of 5 to 300 nm determined from an electron micrograph and a density of 1.20 g/cm3 or more determined from a specific surface area determined by a BET method using nitrogen adsorption, wherein the dispersion liquid has a pH of less than 8, a silica concentration of 12 to 40% by mass, and a viscosity in terms of a silica concentration of 20% by mass of 40 mPa·s or less. When this silica particle is used as an abrasive, it is possible to realize a sufficient polishing speed and a smooth polished surface on which occurrence of scratches is suppressed.

Abstract: A method for producing a dispersion liquid of silica particles, by simultaneously adding a liquid A containing silane alkoxide and a liquid B containing an alkali catalyst and water to a liquid I containing silica seed particles to cause the particles to grow, so as to produce silica particles; wherein the variation rate of the mole ratio of the alkali catalyst to silica components in the reaction system during a period from the start to the end of the addition relative to the initial mole ratio is 0.90 to 1.10; and the variation rate of the mole ratio of water to the silica components in the reaction system during a period from the start to the end of the addition relative to the initial mole ratio is 0.90 to 1.10.

Abstract: A method for producing a liquid dispersion containing irregular-shaped silica particles in which two or more primary particles are linked together, by simultaneously adding a liquid A containing silane alkoxide and a liquid B containing an alkali catalyst and water to a liquid I consisting substantially of an organic solvent to cause hydrolysis and polycondensation of the silane alkoxide, wherein the period from the start of the addition until the silica concentration of the reaction system at the end of the addition reaches 70% is 20% or less of the full reaction time period.

Abstract: Provided is a production method of a silica particle dispersion liquid which includes, preparing a linked silica particle by adding a liquid A containing alkoxysilane and a liquid B containing an alkali catalyst to a liquid containing water, an organic solvent, and an alkali catalyst in a container. The preparing a linked silica particle includes initially adding an alkali catalyst, the initially adding an alkali catalyst includes decreasing a molar ratio of an alkali catalyst to silica in the liquid in the container to 0.15 to 0.60 by adding the liquid A containing alkoxysilane to the liquid in the container, and increasing the molar ratio by 0.2 or more by adding the liquid B to the liquid having the decreased molar ratio in the container.

Abstract: There are provided spherical porous silica particles that do not disintegrate during production and exhibit high disintegration properties (easily disintegrating properties) during use, so as to be used in an abrasive to perform precise abrading, a scrub material of cosmetics, or the like. There have been achieved porous silica particles that have an average particle diameter of 0.5 to 50 ?m, a pore volume of 0.5 to 5.0 cm3/g, a mode of a pore diameter of 2 to 50 nm, a shape factor of 0.8 to 1.0, an average compression strength of 0.1 to less than 1.0 kgf/mm2, and a sodium content of 10 ppm or less, and possess a network structure.

Abstract: A silica particle dispersion liquid includes a silica particle that satisfies (i) to (iii) below: (i) an average particle diameter d is 5 to 300 nm; (ii) an occlusion amount of a basic substance per 1 g of the particle is 2 mg or more; and (iii) a Sears number Y exceeds 12.0.

Abstract: A polishing composition that can not only achieve high polishing speed, but also can improve the surface smoothness (surface quality) of a polished substrate and reduce defects is provided. That is, provided is a polishing composition comprising silica particles and a water soluble polymer, wherein the contained silica particles satisfy the following requirements (a) to (c): (a) the primary particle diameter based on the specific surface area is 5 to 300 nm; (b) the coefficient of variation in the particle diameter is 10% or less; and (c) the Sears number Y is 10.0 to 12.0.

Abstract: There is provided a production method of a chain silica particle dispersion. This production method includes a dispersion preparation step of hydrolyzing alkoxysilane in the presence of ammonia to prepare a silica particle dispersion, an ammonia removal step of removing the ammonia from the silica particle dispersion such that an ammonia amount relative to silica contained in the silica particle dispersion is 0.3% by mass or less, and a hydrothermal treatment step of hydrothermally treating the silica particle dispersion having a silica concentration of 12% by mass or more, from which the ammonia has been removed, at a temperature of not lower than 150° C. and lower than 250° C. An abrasive including such chain silica particles is high in polishing rate and excellent in polishing properties.

Abstract: Provided is a dispersion liquid of silica particles, comprising silica particles having an average particle diameter of 5 to 300 nm determined from an electron micrograph and a density of 1.20 g/cm3 or more determined from a specific surface area determined by a BET method using nitrogen adsorption, wherein the dispersion liquid has a pH of less than 8, a silica concentration of 12 to 40% by mass, and a viscosity in terms of a silica concentration of 20% by mass of 40 mPa·s or less. When this silica particle is used as an abrasive, it is possible to realize a sufficient polishing speed and a smooth polished surface on which occurrence of scratches is suppressed.

Abstract: A method for producing a dispersion liquid of silica particles, by simultaneously adding a liquid A containing silane alkoxide and a liquid B containing an alkali catalyst and water to a liquid I containing silica seed particles to cause the particles to grow, so as to produce silica particles; wherein the variation rate of the mole ratio of the alkali catalyst to silica components in the reaction system during a period from the start to the end of the addition relative to the initial mole ratio is 0.90 to 1.10; and the variation rate of the mole ratio of water to the silica components in the reaction system during a period from the start to the end of the addition relative to the initial mole ratio is 0.90 to 1.10.

Abstract: Provided are titanium oxide fine particles which are excellent in transparency and are less photocatalytically active while maintaining a high refractive index, a dispersion of such fine particles, and a method for producing such a dispersion. The method for producing a dispersion of iron-containing rutile titanium oxide fine particles including a step (1) of neutralizing an aqueous metal mineral acid salt solution containing Ti and Fe in Fe2O3/(TiO2+Fe2O3)=0.001 to 0.010 to form an iron-containing hydrous titanic acid; a step (2) of adding an aqueous hydrogen peroxide solution to form an aqueous solution of iron-containing peroxotitanic acid having an average particle size of 15 to 50 nm; a step (3) of adding a tin compound so as to satisfy TiO2/SnO2=6 to 16; a step (4) of adding a sol of silica-based fine particles which contain Si and a metal element M in SiO2/MOx/2=99.9/0.1 to 80/20, the addition being made so as to satisfy SiO2/(oxides of the other elements)=0.08 to 0.

Abstract: A method for producing a liquid dispersion containing irregular-shaped silica particles in which two or more primary particles are linked together, by simultaneously adding a liquid A containing silane alkoxide and a liquid B containing an alkali catalyst and water to a liquid I consisting substantially of an organic solvent to cause hydrolysis and polycondensation of the silane alkoxide, wherein the period from the start of the addition until the silica concentration of the reaction system at the end of the addition reaches 70% is 20% or less of the full reaction time period.

Abstract: Silica particles calcined in a calcination step are supplied in a swirling flow generated by a gas introduced in a disintegration container and disintegrated therein, whereby the silica particles can be easily disintegrated and there can be obtained disintegrated silica particles having both low hygroscopicity and high dispersibility in resin. In addition, the introduction of dehumidified air (gas) during the disintegration reduces hygroscopicity and greatly improves dispersibility in resin. Furthermore, performing heating treatment (calcination) again after the disintegration causes the surface modification of the disintegrated silica particles, greatly improving hygroscopicity and dispersibility in resin. The resin composition obtained in this manner including silica particles provides good injectability and filterability when used for an underfill material for semiconductors and an in-plane spacer or sealing spacer of liquid crystal displays.

Abstract: Producing a silica particle by inhibiting the generation of incompletely reacted materials such as oligomers which have not been grown to the silica particles having the intended particle size. A dispersion liquid of a silica particle is produced by simultaneously adding, to a liquid substantially consisting of an organic solvent, a liquid containing silane alkoxide and a liquid containing an alkali catalyst and water to cause hydrolysis and polycondensations to produce a silica particle. The variation rate of the mole ratio of the alkali catalyst to silane alkoxide in the reaction system for a period from the start to the end of the reaction relative to the initial mole ratio is 0.90 to 1.10; and the variation rate of the mole ratio of water to silane alkoxide for a period from the start to the end of the reaction relative to the initial mole ratio is 0.90 to 1.10.