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EP-4737393-A1 - DISPERSION OF TITANIUM DIOXIDE FINE PARTICLES IN ORGANIC SOLVENT, METHOD FOR PRODUCING SAME, AND USE OF SAME

EP4737393A1EP 4737393 A1EP4737393 A1EP 4737393A1EP-4737393-A1

Abstract

The present invention addresses the problem of providing: a dispersion of titanium dioxide fine particles in an organic solvent, the dispersion having high dispersion stability; and a method for producing the same. The present invention provides a dispersion of titanium dioxide fine particles in an organic solvent, the dispersion containing: titanium dioxide fine particles in each of which a titanium component, a tin component, and an aluminum component are detected by X-ray fluorescence analysis measurement, and an X-ray diffraction peak derived from rutile titanium dioxide is observed but X-ray diffraction peaks derived from the tin component and the aluminum component are not observed by powder X-ray diffraction measurement; an organic solvent; a silane coupling agent; and a dispersant that has a basic adsorption group.

Inventors

  • TAKIMOTO, TADAHIKO
  • GOTO, KOUJI
  • WASHIZU, HIROKI

Assignees

  • Ishihara Sangyo Kaisha, Ltd.

Dates

Publication Date
20260506
Application Date
20240626

Claims (17)

  1. An organic solvent dispersion of titanium dioxide fine particles comprising: the titanium dioxide fine particles in which a titanium component, a tin component and an aluminum component are detected by means of X-ray fluorescence measurement, and an X-ray diffraction peak derived from rutile-type titanium dioxide is observed and X-ray diffraction peaks derived from a tin component and an aluminum component are not observed by means of powder X-ray diffraction measurement; an organic solvent; a silane coupling agent; and a dispersant having a basic adsorption group.
  2. An organic solvent dispersion of titanium dioxide fine particles comprising: the titanium dioxide fine particles in which a titanium component, a tin component and an aluminum component are detected by means of X-ray fluorescence measurement, and only an X-ray diffraction peak derived from rutile-type titanium dioxide is observed and X-ray diffraction peaks derived from a tin component and an aluminum component are not observed by means of powder X-ray diffraction measurement; an organic solvent; a silane coupling agent; and a dispersant having a basic adsorption group.
  3. The organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, wherein the titanium dioxide fine particles comprise titanium dioxide fine particles in which a tin component and an aluminum component are present as a solid solution.
  4. The organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, wherein a total of an amount of the tin component and an amount of the aluminum component with respect to an amount of the titanium component in the titanium dioxide fine particles is 0.6 mass% or more and 30 mass% or less when expressed as a mass ratio given by [(amount of SnO 2 + amount of Al 2 O 3 )/amount of TiO 2 ], wherein the amount of TiO 2 is the amount of the titanium component in terms of the amount of TiO 2 , the amount of SnO 2 is the amount of the tin component in terms of the amount of SnO 2 , and the amount of Al 2 O 3 is the amount of the aluminum component in terms of the amount of Al 2 O 3 .
  5. The organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, wherein the amount of the tin component with respect to the amount of the aluminum component is 0.01 mass% or more and 40 mass% or less when expressed as a mass ratio given by [amount of SnO 2 /amount of Al 2 O 3 ], wherein the amount of Al 2 O 3 is the amount of the aluminum component in terms of the amount of Al 2 O 3 , and the amount of SnO 2 is the amount of the tin component in terms of the amount of SnO 2 .
  6. The organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, wherein a mass ratio of the dispersant having a basic adsorption group to the silane coupling agent is 15 mass% or more and 75 mass% or less.
  7. The organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, wherein the titanium dioxide fine particles comprise titanium dioxide fine particles in which one or more components selected from the group consisting of a silicon component, a cobalt component and a manganese component are further detected by means of X-ray fluorescence measurement, and X-ray diffraction peaks derived from one or more components selected from the group consisting of a silicon component, a cobalt component and a manganese component are not observed by means of powder X-ray diffraction measurement.
  8. The organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, wherein the titanium dioxide fine particles comprise titanium dioxide fine particles in which one or more components selected from the group consisting of the silicon component, the cobalt component and the manganese component are present as a solid solution.
  9. The organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, wherein surfaces of the titanium dioxide fine particles are covered with an inorganic compound.
  10. A coating composition comprising the organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, and a binder resin.
  11. A paint film comprising the organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, and a binder resin.
  12. A composition for nanoimprinting comprising the organic solvent dispersion of titanium dioxide fine particles according to claim 1 or 2, and a binder resin.
  13. A method for producing an organic solvent dispersion of titanium dioxide fine particles, the method comprising the step of dispersing, in an organic solvent, the following: titanium dioxide fine particles in which a titanium component, a tin component and an aluminum component are detected by means of X-ray fluorescence measurement, and an X-ray diffraction peak derived from rutile-type titanium dioxide is observed and X-ray diffraction peaks derived from a tin component and an aluminum component are not observed by means of powder X-ray diffraction measurement; a silane coupling agent; and a dispersant having a basic adsorption group.
  14. A method for producing an organic solvent dispersion of titanium dioxide fine particles, the method comprising the step of dispersing, in an organic solvent, the following: titanium dioxide fine particles in which a titanium component, a tin component and an aluminum component are detected by means of X-ray fluorescence measurement, and only an X-ray diffraction peak derived from rutile-type titanium dioxide is observed and X-ray diffraction peaks derived from a tin component and an aluminum component are not observed by means of powder X-ray diffraction measurement; a silane coupling agent; and a dispersant having a basic adsorption group.
  15. The method for producing an organic solvent dispersion of titanium dioxide fine particles according to claim 13 or 14, further comprising centrifuging the organic solvent dispersion.
  16. The method for producing an organic solvent dispersion of titanium dioxide fine particles according to claim 13 or 14, wherein the titanium dioxide fine particles are produced by the following steps: Step (1): a step of hydrolyzing a mixture of titanium (oxy)chloride and a tin compound, or a step of hydrolyzing titanium (oxy)chloride in the presence of core particles obtained by hydrolyzing a tin compound; Step (2): a step of mixing a product obtained by the hydrolysis in the Step (1) with an aluminum compound; and Step (3): a step of performing a treatment comprising firing the mixture of the product obtained by the hydrolysis in the Step (1) with the aluminum compound at a temperature of 250°C or higher and 1,000°C or lower.
  17. The method for producing an organic solvent dispersion of titanium dioxide fine particles according to claim 16, wherein the Step (1) is a step of hydrolyzing a mixture of titanium (oxy)chloride, a tin compound, and a carboxylic acid or a salt thereof, or a step of adding titanium (oxy)chloride, and a carboxylic acid or a salt thereof in the presence of core particles obtained by hydrolyzing a tin compound, and hydrolyzing the titanium (oxy)chloride.

Description

TECHNICAL FIELD The present invention relates to an organic solvent dispersion of titanium dioxide fine particles, a method for producing the dispersion, and the intended use of the dispersion. BACKGROUND ART Titanium dioxide fine particles are a material having excellent characteristics such as a visible light transmittance (that is, transparency), an ultraviolet ray shielding property and a high refractive index. The use of the characteristics typically requires dispersing titanium dioxide fine particles in an organic solvent to prepare an organic solvent dispersion or a coating composition, and applying or spraying the dispersion or the coating composition to a substrate to form a paint film including the titanium dioxide fine particles. The organic solvent dispersion of titanium dioxide fine particles is used, for example, to form a hard coat, an ultraviolet ray shielding coating film or the like, each having a high visible light transmittance (that is, transparency) and a high refractive index on a surface of a substrate such as a synthetic resin lens or a film. Additionally, an antireflection film in which a high-refractive-index layer and a low-refractive-index layer are combined is provided on a display surface of a flat panel display such as a liquid crystal display, a plasma display, or an electroluminescence display for the purpose of, for example, avoiding reflection of a light source or a face, and the organic solvent dispersion of titanium dioxide fine particles is used in the high-refractive-index layer. However, the organic solvent dispersion of titanium dioxide fine particles has a problem that the titanium dioxide fine particles are likely to agglomerate in the organic solvent dispersion. Since the organic solvent dispersion including agglomerated titanium dioxide fine particles has low transparency, a paint film prepared using the organic solvent dispersion also results in reduced transparency. Further, in the organic solvent dispersion including agglomerated titanium dioxide fine particles, the titanium dioxide fine particles are settled in the course of production of the organic solvent dispersion, and thus, the yield of the organic solvent dispersion that can be used in the paint film reduces. For the above reasons, studies have been performed on a method for obtaining an organic solvent dispersion of titanium dioxide fine particles, which has excellent dispersion stability. For example, Patent Literature 1 discloses an organic solvent dispersion of titanium dioxide fine particles, the organic solvent including titanium dioxide fine particles, an organic solvent, a silane coupling agent, and a dispersant having a basic adsorption group, wherein a mass ratio of the above-mentioned dispersant to the above-mentioned silane coupling agent is 15 mass% to 75 mass%. Patent Literature 1 discloses in Example 2: "An organic solvent dispersion of titanium dioxide fine particles was obtained through the following steps: obtaining unfired titanium dioxide fine particles through the steps of adding a titanium tetrachloride aqueous solution to a tin tetrachloride aqueous solution such that a SnO2/TiO2 ratio can be 1, heating and hydrolyzing this mixture to obtain a slurry of tin-containing rutile-type titanium oxide, using the slurry to obtain a slurry of rutile-type titanium dioxide surface-treated with aluminum hydroxide in which aluminum hydroxide is deposited so as to be an amount of 15 mass% in terms of the amount of Al2O3, and drying the obtained slurry at 150°C; wet-dispersing the obtained unfired titanium dioxide fine particles, a silane coupling agent, a dispersant, and an organic solvent to obtain a dispersion; and centrifuging the obtained dispersion at 2,400 G for 13 minutes, and then collecting a supernatant thereof to obtain an organic solvent dispersion of titanium dioxide fine particles". Patent Literature 2 discloses an organic solvent dispersion liquid of a core-shell-type tetragonal titanium oxide solid solution, wherein the core-shell-type tetragonal titanium oxide solid solution is dispersed in an organic solvent and has, as a core, tetragonal titanium oxide fine particles in which one or more elements (M0) selected from the group consisting of gallium, vanadium, niobium, tantalum, zirconium, aluminum, and indium, and tin are present as a solid solution, and has, as a shell outside the core, silicon oxide. Also, the Patent Literature discloses in Example 6 the following: tin (IV) chloride pentahydrate and aluminum (III) chloride were added to an aqueous solution of titanium (IV) chloride, neutralized with aqueous ammonia, and hydrolyzed to obtain a precipitate of titanium hydroxide including tin and aluminum; and 30 mass% aqueous hydrogen peroxide was added to the precipitate to obtain a translucent tin-containing peroxotitanic acid solution; and then the translucent tin-containing peroxotitanic acid solution was hydrothermally treated in an autoclave under conditions of 200°C an