Abstract: Titanium oxide particles satisfying all of requirements (1) to (3). (1) The titanium oxide particles have a rutile crystal structure. (2) A unit cell of the crystal structure satisfies at least one of (a) or (b). (a) An a-axis has a length of 0.4594 nm or more. (b) A c-axis has a length of 0.2959 nm or more. (3) The titanium oxide particles have an energy gap of 2.90 eV or less.

Abstract: The present invention addresses the problem of providing particles having low photocatalytic activity and a high refractive index by forming an amorphous layer that contains Si and Ti on the surface of crystalline titanium oxide. The problem is solved by core-shell particles wherein the core particles are crystalline titanium oxide and the shell is an amorphous layer that contains Si and Ti.

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: Provided are porous silica particles having balanced appropriate disintegrability and excellent disintegration uniformity, and a method for producing the porous silica particles. The porous silica particles according to the present invention have a network structure, and are elastically deformed to the breaking point when a compressive force increasing at a rate of 0.001450 gf/sec is applied. The ratio “f/d” of the compressive force f (gf) to the displacement amount d (?m) at the breaking point is 0.05 to 0.10. The pore volume of the porous silica particles is 0.4 to 1.3 cm3/g, the mode value of the pore diameter is 2 to 50 nm, the total pore volume of pores having a size within ±25% of the mode value of the pore diameter is 40% or more of the pore volume, the average shape factor is 0.90 to 1.00, the content rate of particles having a shape factor of less than 0.80 is 3.0 number % or less, and the average compressive strength is 9.8 N/mm2 to less than 29.4 N/mm2.

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 porous silica particle has disintegration properties. The porous silica particle has 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, a sodium content of 10 ppm or less, and a network structure.

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: The present invention relates to particles having a rutile-type crystal structure. The particles have a crystallite diameter of 7 nm or more and contains 90% by weight or more of titanium oxide in terms of TiO2 and 0.2 to 10% by weight of tin oxide in terms of SnO2. Such particles are easily dispersed in a solvent and have a high refractive index.

Abstract: Rutile titanium oxide particles, in which Fe and Zr are dissolved to form a solid solution, have an interplanar spacing of a (110) plane obtained by X-ray diffraction measurement of 0.3250 nm or more and an average particle size in a range from 5 nm to 50 nm.

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: 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: 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.