Rutile-type titanium dioxide particles, dispersion, coating solution for film formation, and coated substrate.

Abstract

The present invention provides rutile titanium oxide particles, in which Fe and Zr are a solid solution, the spacing between the (110) planes as obtained by X-ray diffraction is 0.3250 nm or greater, and the average particle diameter is within the range of 5-50 nm.

Description

[Technical Field]

[0001] This invention relates to rutile-type titanium dioxide particles. [Background technology]

[0002] Titanium dioxide is widely used as a photocatalyst, UV-blocking material, and coating agent for forming coatings on optical substrates. The crystalline structures of titanium dioxide are well known as anatase, rutile, and brookite, and different crystalline structures result in different properties. For example, anatase-type titanium dioxide particles have high photocatalytic activity and are used as deodorizing, anti-odor, and anti-fouling materials. On the other hand, rutile-type titanium dioxide particles have a high refractive index and lower photocatalytic activity compared to anatase-type particles, and are therefore used in hard coat layers of substrates. Hard coat layers contain components other than rutile-type titanium dioxide, such as organosilicon compounds and resins, and if the photocatalytic activity of these particles is too strong, they can decompose these components. Such decomposition can lead to cracks in the hard coat layer and reduced adhesion between the substrate and the hard coat layer, becoming a problem when substrates with titanium dioxide-containing layers are used in the presence of ultraviolet light, such as sunlight (weather resistance). This problem persists even when using ordinary rutile-type titanium dioxide, which is generally considered to have lower photocatalytic activity than other crystalline forms, and various solutions have been proposed.

[0003] For example, Patent Document 1 discloses a method for providing a coating liquid for forming a hard coat film that has a high refractive index, excellent transparency, weather resistance, and adhesion to a substrate, by incorporating composite oxide particles in the coating liquid for forming the film, in which titanium oxide and iron oxide components are present in a Fe2O3 / TiO2 (weight ratio) of 0.0005 or more and less than 0.005. Patent Document 2 also discloses a coating liquid for forming a hard coat film that has a high refractive index, excellent transparency, excellent resistance to hot water, weather resistance, scratch resistance, abrasion resistance, and dyeability, is non-photochromic, and also has excellent adhesion to a substrate, as well as composite oxide particles for providing a hard coat film-coated substrate on which such an excellent hard coat film is formed on the surface. Specifically, the disclosed composite oxide particles consist of iron oxide, titanium oxide, and silica, and when iron oxide is converted to Fe2O3, titanium oxide to TiO2, and silica to SiO2, the weight ratio Fe2O3 / TiO2 is in the range of 0.0005 or more and less than 0.005, and the weight ratio SiO2 / (Fe2O3+TiO2) is in the range of 0.001 or more and 1.0 or less. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 05-002102 [Patent Document 2] Japanese Patent Application Publication No. 11-172152 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] According to the inventors' findings, conventional coating films containing titanium oxide particles with added heterogeneous elements show some improvement in weather resistance, but they still have the problem of coloration, leaving room for further improvement.

[0006] Therefore, the present invention aims to provide titanium oxide particles that can produce a coating film with excellent weather resistance and minimal discoloration. [Means for solving the problem]

[0007] According to one aspect of the present invention, the following rutile-type titanium oxide particles are provided. [1] Fe and Zr are in solid solution, The interplanar spacing of the (110) plane obtained by X-ray diffraction measurement is 0.3250 nm or more. The average particle diameter is in the range of 5 nm or more and 50 nm or less. Rutile-type titanium dioxide particles. [2] Rutile titanium oxide particles as described in [1], wherein the Ti content is in the range of 40% by mass or more and 90% by mass or less in terms of TiO2 relative to the total amount of rutile titanium oxide particles. [3] Rutile titanium oxide particles according to [1] or [2], wherein the Fe content is in the range of 0.01 mol% or more and 5 mol% or less in molar percent relative to Ti. [4] Rutile titanium oxide particles according to any one of [1] to [3], wherein the Zr content is in the range of 0.1 mol% or more and 15 mol% or less in molar percent relative to Ti. [5] Rutile titanium oxide particles according to any one of [1] to [4], wherein the Sn content is in the range of 1 mol% or more and 30 mol% or less relative to Ti. [6] Rutile-type titanium oxide particles according to any one of [1] to [5], wherein the Si content is in the range of 5 mol% or more and 70 mol% or less relative to Ti. [7] Rutile-type titanium oxide particles according to any of [1] to [6], wherein the Zr / Fe molar ratio is 1 or greater. [8] A dispersion containing rutile-type titanium dioxide particles as described in any of [1] to [7]. A coating solution for forming a coating film, comprising rutile-type titanium dioxide particles and a matrix-forming component as described in any of [9] [1] to [7]. A coated substrate containing rutile-type titanium dioxide particles as described in any of [1] to [7].

[0008] According to the present invention, titanium oxide particles can be provided that can produce a coating film with excellent weather resistance and minimal discoloration. [Modes for carrying out the invention]

[0009] The inventors have discovered that by solid-solving Fe and Zr in rutile-type titanium dioxide, particles with low photocatalytic activity can be obtained. Coating films containing these particles exhibit significantly improved weather resistance. Furthermore, the problem of discoloration that often occurs in coating films containing particles obtained by solid-solving Fe in rutile-type titanium dioxide is resolved by the unique combination of elements Fe and Zr.

[0010] The present invention relates to rutile-type titanium oxide particles in which Fe and Zr are solid-solved, the interplanar spacing of the (110) plane obtained by X-ray diffraction measurement is 0.3250 nm or more, and the average particle diameter is in the range of 5 nm to 50 nm.

[0011] The rutile-type titanium oxide particles of the present invention (hereinafter also referred to as the titanium oxide particles of the present invention) will be described in detail below.

[0012] [Titanium dioxide particles] The titanium dioxide particles of the present invention are rutile-type titanium dioxide. Rutile-type titanium dioxide has lower photocatalytic activity compared to titanium dioxide with other crystalline structures, making it suitable as a material for obtaining highly weather-resistant coatings. Furthermore, in terms of refractive index, rutile-type titanium dioxide has a higher refractive index compared to titanium dioxide with other crystalline structures, making it suitable for use as an optical material, for example. Moreover, it has a narrower band gap and superior ultraviolet (UV) absorption capacity compared to titanium dioxide with other crystalline structures, making it suitable for use as a UV-absorbing material. When such a UV-absorbing material is applied to a substrate, UV degradation of the substrate can be suppressed, and the weather resistance of the coated substrate can be improved. Other crystalline structures of titanium dioxide include anatase-type and brookite-type, which can be distinguished by X-ray diffraction measurement.

[0013] The content of Ti contained in the titanium oxide particles of the present invention is preferably in the range of 40% by mass or more and 90% by mass or less in terms of TiO2 conversion with respect to the total amount of rutile-type titanium oxide particles, more preferably in the range of 45% by mass or more and 80% by mass or less, and particularly preferably in the range of 50% by mass or more and 70% by mass or less. If the content of Ti is too low, the refractive index and UV absorption ability are likely to decrease. Also, even if the content of Ti is too high, the photocatalytic activity will become high. Therefore, when the content of Ti is within the aforementioned range, rutile-type titanium oxide particles with a high refractive index and UV absorption ability and a low photocatalytic activity can be obtained.

[0014] Fe and Zr are solid-dissolved in the titanium oxide particles of the present invention. Generally, solid solution means that two or more kinds of elements (either metals or non-metals) are mutually dissolved and the whole becomes a uniform solid phase. Such solid solutions are classified into substitutional solid solutions and interstitial solid solutions. Whether it is a substitutional solid solution or an interstitial solid solution, if Fe and Zr are solid-dissolved, the crystal lattice of rutile-type titanium oxide will fluctuate. Such fluctuations in the crystal lattice can be observed by X-ray diffraction measurement. For the titanium oxide particles of the present invention, when Fe and Zr are solid-dissolved, the interplanar spacing of the (110) plane obtained by X-ray diffraction measurement becomes 0.3250 nm or more.

[0015] The content of Fe contained in the titanium oxide particles of the present invention is preferably in the range of 0.01 mol% or more and 5 mol% or less in terms of mol% with respect to Ti (when the amount of Ti is 100 mol%), more preferably in the range of 0.05 mol% or more and 3 mol% or less, and particularly preferably in the range of 0.08 mol% or more and 2 mol% or less. When the content of Fe is within the aforementioned range, the photocatalytic activity of the rutile-type titanium oxide particles decreases and the coloring also decreases.

[0016] The content of Zr contained in the titanium oxide particles of the present invention is preferably in the range of 0.1 mol% or more and 15 mol% or less, more preferably in the range of 1 mol% or more and 10 mol% or less, and particularly preferably in the range of 3 mol% or more and 7 mol% or less, in terms of mol% with respect to Ti. The titanium oxide particles of the present invention in which Zr is dissolved together with Fe have significantly lower photocatalytic activity than the titanium oxide particles in which each is dissolved alone. Due to this synergistic effect, it is possible to reduce the photocatalytic activity while minimizing the coloring that occurs when Fe is dissolved.

[0017] The molar ratio (Zr / Fe) of Fe and Zr contained in the titanium oxide particles of the present invention is preferably 1 or more, more preferably in the range of 1 or more and 30 or less, and particularly preferably in the range of 1 or more and 15 or less. When the molar ratio of Fe and Zr is within the above-mentioned range, titanium oxide particles with lower photocatalytic activity and less coloring can be obtained.

[0018] The titanium oxide particles of the present invention preferably contain elements other than Ti, Fe, and Zr. Specifically, it is preferable to contain at least one element selected from Sn, Si, K, and Al, and it is particularly preferable to contain Sn or Si. Sn has the function of enhancing the crystallinity of rutile-type titanium oxide and suppressing the formation of crystal structures other than rutile-type such as anatase-type. Thereby, the weather resistance of the titanium oxide particles of the present invention is further improved and the transparency is also increased. From this viewpoint, the content of Sn is preferably in the range of 1 mol% or more and 30 mol% or less, more preferably in the range of 3 mol% or more and 20 mol% or less, and particularly preferably in the range of 5 mol% or more and 15 mol% or less, in terms of mol% with respect to Ti. Also, Si further reduces the photocatalytic activity of the titanium oxide particles of the present invention. From this viewpoint, the content of Si is preferably in the range of 5 mol% or more and 70 mol% or less, more preferably in the range of 10 mol% or more and 50 mol% or less, and particularly preferably in the range of 15 mol% or more and 40 mol% or less, in terms of mol% with respect to Ti. The content of elements other than Ti, Fe, and Zr is preferably in the range of 5 mol% to 120 mol%, more preferably in the range of 10 mol% to 70 mol%, and particularly preferably in the range of 20 mol% to 50 mol% relative to Ti. When the content of elements other than Ti, Fe, and Zr is within the above range, titanium oxide particles with a high refractive index and low photocatalytic activity can be obtained.

[0019] The titanium oxide particles of the present invention are preferably coated particles with a coating layer formed on their surface. For example, if a coating layer containing at least one element selected from Zr, Si, Al, and Sb is formed, the photocatalytic activity of the titanium oxide particles of the present invention can be further reduced. In particular, if a coating layer containing either or both Si and Zr is formed, the photocatalytic activity can be further reduced, and dispersibility in polar solvents such as water or alcohol tends to be good.

[0020] The surface of the titanium oxide particles or the surface of the coating layer of the present invention preferably has a surface treatment layer that has been surface-treated with an organosilicon compound such as a silane coupling agent or an amine compound. Modifying these surfaces with an organosilicon compound or an amine compound improves their dispersibility with resins and organic solvent components contained in the dispersion or coating liquid for film formation described later.

[0021] The proportion of the coating layer contained in the titanium oxide particles of the present invention is preferably in the range of 1% to 30% by mass, more preferably in the range of 1% to 20% by mass, and particularly preferably in the range of 3% to 10% by mass, relative to the total amount of coating particles, in terms of oxide. In the case of a coating layer containing Zr, Si, Al, and Sb, the amount of the coating layer is calculated by converting it to ZrO2, SiO2, Al2O3, and Sb2O5, respectively. If other elements are included, the oxide shall be estimated from the valence of the raw material. For example, if K derived from KOH is included, it shall be converted as K2O. If there are fluctuations in the valence of the raw material during the manufacturing process, the valence of the element shall be determined by performing X-ray photoelectron spectroscopy (XPS measurement) on the finally obtained coating particles. Specifically, from the spectrum obtained by XPS measurement, the peaks attributed to each valence shall be identified, and the oxide shall be estimated based on the valence of the peak with the greatest peak intensity. For example, Cu + Cu 2+ A peak appears, Cu 2+ If the peak intensity is stronger, it shall be converted to CuO. Furthermore, the proportion of the surface treatment layer is preferably in the range of 1% by mass or more and 10% by mass or less, more preferably in the range of 2% by mass or more and 9% by mass or less, and particularly preferably in the range of 3% by mass or more and 8% by mass or less, relative to the total amount of coated particles. The proportion of the surface treatment layer shall be calculated by converting the inorganic components contained in the surface treatment layer to oxides. For example, if the surface treatment layer contains a silane coupling agent, the Si contained in the surface treatment layer shall be calculated by converting it to SiO2.

[0022] The average particle size of the titanium oxide particles of the present invention is in the range of 5 nm or more and 50 nm or less, preferably in the range of 8 nm or more and 40 nm or less, and more preferably in the range of 10 nm or more and 30 nm or less. When the average particle size is within the above range, a dense coating film is easily formed when forming a coating film containing the titanium oxide particles of the present invention. In the present invention, the value of the average particle size is obtained by measuring the size of primary particles using an electron microscope and taking the average.

[0023] The refractive index of the titanium oxide particles of the present invention is preferably 1.8 or higher, more preferably 2 or higher, and particularly preferably 2.1 or higher. Titanium oxide particles of the present invention having such a high refractive index can be suitably used for optical materials. The upper limit of the refractive index is not particularly limited, but may be 3 or less.

[0024] The yellowness (YI value) of the titanium dioxide particles of the present invention is preferably 58 or less, and more preferably 55 or less. When Fe is dissolved in rutile-type titanium dioxide, this value increases, and the yellowness intensifies. However, the titanium dioxide particles of the present invention, by dissolving Zr together with Fe, can exhibit a high photocatalytic activity inhibitory effect even with a small amount of Fe, thus achieving both low discoloration and high weather resistance.

[0025] The photocatalytic activity of the titanium dioxide particles of the present invention can be determined by irradiating a system of titanium dioxide particles and dye with ultraviolet light for 3 hours and measuring the rate of change in absorbance (fading rate) before and after irradiation. The fading rate of the titanium dioxide particles of the present invention is preferably 30% or less, more preferably 20% or less, even more preferably 15% or less, and particularly preferably 10% or less. A higher photocatalytic activity results in a higher fading rate, and a lower photocatalytic activity results in a lower fading rate. The titanium dioxide particles of the present invention have a low fading rate, i.e., low photocatalytic activity.

[0026] [Dispersion containing titanium dioxide particles] The titanium dioxide particles of the present invention may be in the form of a powder or a dispersion in a solvent. In the case of a dispersion, it may be an aqueous dispersion, a dispersion of water and an organic solvent, or an organic solvent dispersion. In a dispersion containing an organic solvent as the dispersion medium, some or all of the water contained in the dispersion can be replaced with the organic solvent by, for example, a rotary evaporator, an ultrafiltration membrane, or other known method.

[0027] Organic solvents that can be used in the dispersion containing titanium oxide particles of the present invention include, for example, Alcohols such as methanol, ethanol, ethylene glycol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and octanol; Esters such as ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and γ-butyrolactone; Ethers such as diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, and cyclohexanone; Aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; Cyclohexane and other cyclic hydrocarbons; and; Examples include amides such as dimethylformamide, N,N-dimethylacetacetamide, and N-methylpyrrolidone. These organic solvents may be used individually or in combination of two or more.

[0028] [Coating solution for film formation containing titanium dioxide particles] The dispersion containing titanium oxide particles of the present invention can also be used as a coating solution for film formation by adding a matrix-forming component. As the matrix-forming component, a matrix-forming component commonly used in coating solutions for film formation can be used. Examples include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, phenylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane. These may be used individually or in combination of two or more types.

[0029] [Coated substrate containing titanium dioxide particles] A dispersion containing the titanium dioxide particles of the present invention can be used to form a coating film on various substrates such as glass or plastic, creating a coated substrate. This coated substrate can be used as an optical substrate for eyeglass lenses, various optical lenses such as those for cameras, front panels for optical displays, display cases, window glass, contact glass for photocopiers, light covers for automobiles, and various UV-shielding filters. The titanium dioxide particles of the present invention have low photocatalytic activity while possessing UV absorption ability, thus enabling the creation of a coating film with high weather resistance in any configuration. The film thickness is not particularly limited, but since the titanium dioxide particles of the present invention have little coloration, coloration of the coating film is less likely to occur even with a large film thickness. In particular, when seeking to obtain coating film strength (e.g., evaluation by Bayer test), a film thickness of 0.5 μm or more is preferable, 1 μm or more is more preferable, and 2 μm or more is especially preferable. The upper limit of the film thickness is not particularly limited, but it may be 100 μm or less, 50 μm or less, or 30 μm or less.

[0030] [Method for producing titanium dioxide particles] The titanium oxide particles of the present invention can be prepared, for example, by a manufacturing method comprising the following steps (1) to (3). However, the manufacturing method of the titanium oxide particles of the present invention is not limited to the following method. (1) Co-precipitation gel preparation process (2) Hydrothermal treatment precursor preparation process (3) Hydrothermal treatment process The method for preparing titanium oxide particles according to the present invention will be described in detail below.

[0031] (1) Co-precipitation gel preparation process In this step, an aqueous solution containing Ti, Fe, and Zr is neutralized to prepare a coprecipitation gel containing Ti, Fe, and Zr. Preparing a coprecipitation gel containing Ti, Fe, and Zr further promotes the solid solution of Fe and Zr into the final rutile-type titanium oxide.

[0032] Aqueous solutions containing Ti, Fe, and Zr can be prepared by dissolving a Ti source, an Fe source, and a Zr source in water. The Ti source can be conventionally known raw materials such as titanium tetrachloride, titanium sulfate, and titanium alkoxide. The Fe source can be conventionally known raw materials such as iron chloride, iron sulfate, iron nitrate, and iron acetate. Furthermore, the Zr source can be conventionally known raw materials such as zirconium chloride, zirconium carbonate, and zirconium nitrate. The pH of the aqueous solution containing Ti, Fe, and Zr is preferably 3 or less.

[0033] In this process, an alkali with a pH of 10 or higher can be used to neutralize the aforementioned aqueous solution. For example, an alkaline aqueous solution of sodium hydroxide, potassium hydroxide, or ammonia dissolved in water can be used. By mixing the aforementioned aqueous solution and the alkaline aqueous solution until the pH is in the range of 4 to 10, a coprecipitation gel containing Ti, Fe, and Zr is formed. This coprecipitation gel can be recovered by filtration and may be washed with water or other means as necessary.

[0034] (2) Hydrothermal treatment precursor preparation process In this step, the coprecipitation gel obtained in the previous step is redispersed (disintegrated) in water to prepare a hydrothermal treatment precursor.

[0035] Conventional methods can be used to disintegrate the coprecipitation gel. For example, methods such as dispersing the coprecipitation gel in water and sonicating it, or dispersing it in water using an acid or alkali can be used. Alternatively, hydrogen peroxide solution may be used to disintegrate it. In this case, it is preferable to adjust the amount of water so that the concentration of solids in the final hydrothermal treatment precursor is 10% by mass or less.

[0036] The average particle size of the solids contained in the hydrothermal treatment precursor obtained in this process is preferably in the range of 5 nm or more and 50 nm or less, more preferably in the range of 10 nm or more and 40 nm or less, and particularly preferably in the range of 15 nm or more and 30 nm or less. If the average particle size of the solids contained in the coprecipitation gel aqueous dispersion becomes large, the average particle size of the rutile-type titanium dioxide finally obtained also tends to become large. Therefore, it is preferable to adjust the average particle size of the solids contained in the coprecipitation gel dispersion so that it is close to the average particle size of the rutile-type titanium dioxide particles of the present invention.

[0037] In this step, after disintegrating the coprecipitation gel, specific elemental components may be added. For example, raw materials containing elements such as Sn, Si, or Al may be added. These raw materials are preferably water-soluble. If they are not water-soluble, raw materials dispersed in the form of fine particles such as a sol are preferred. In this case, when using salts containing alkali metals or alkaline earth metals as raw materials, it is preferable to dissolve the raw materials and then remove the alkali metals or alkaline earth metals using a cation exchange resin or the like.

[0038] (3) Hydrothermal treatment process In this step, the hydrothermal treatment precursor obtained in the previous step is subjected to hydrothermal treatment to prepare rutile-type titanium oxide particles in which Fe and Zr are solid-solved.

[0039] In this process, the hydrothermal treatment precursor can be hydrothermally treated using conventionally known equipment such as an autoclave. The hydrothermal treatment temperature is preferably in the range of 100°C to 250°C, more preferably in the range of 120°C to 220°C, and particularly preferably in the range of 130°C to 210°C. The holding time in the aforementioned temperature range is preferably 1 hour to 48 hours, more preferably 5 hours to 24 hours, and particularly preferably in the range of 10 hours to 20 hours.

[0040] The liquid after hydrothermal treatment contains the rutile-type titanium oxide of the present invention, and separation, washing, etc., may be performed as necessary. Furthermore, the separated rutile-type titanium oxide can be calcined to enhance its crystallinity.

[0041] When forming a coating layer on the surface of the titanium oxide particles of the present invention, for example, it can be formed by the method described in Japanese Patent Application Publication No. 2009-155496. Furthermore, when the titanium oxide particles of the present invention are dispersed in an organic solvent or in a solution containing a dispersed resin, the surface or the surface of the coating layer can be hydrophobized (surface treated) using the method described in the same publication.

[0042] [Method for producing a dispersion containing titanium dioxide particles] A dispersion containing the titanium dioxide particles of the present invention can be prepared by dispersing the titanium dioxide particles of the present invention in a solvent. Conventional known methods can be used to disperse the titanium dioxide particles in the solvent. For example, if the titanium dioxide particles of the present invention are in powder form, a dispersion can be prepared by adding them to water or an organic solvent, followed by a dispersion treatment such as bead milling or ultrasonic treatment. In this case, setting the solid content concentration in the dispersion to 10% by mass or less makes it easier to disperse the titanium dioxide particles of the present invention in the solvent. Furthermore, the zeta potential of the titanium dioxide particles of the present invention can be measured, and the pH can be adjusted to a range suitable for dispersion.

[0043] When an organic solvent is used as the solvent for the dispersion containing titanium oxide particles of the present invention, for example, Alcohols such as methanol, ethanol, ethylene glycol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and octanol; Esters such as ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and γ-butyrolactone; Ethers such as diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, and cyclohexanone; Aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; Cyclohexane and other cyclic hydrocarbons; and; Examples include amides such as dimethylformamide, N,N-dimethylacetacetamide, and N-methylpyrrolidone. These organic solvents may be used individually or in combination of two or more.

[0044] [Method for manufacturing a coating solution for film formation containing titanium dioxide particles] The coating solution for forming a coating film containing the titanium oxide particles of the present invention can be prepared using the titanium oxide particles of the present invention by conventionally known methods. For example, it can be prepared by adding the components necessary for forming a coating film to the aforementioned dispersion. This coating solution for forming a coating film may be a thermosetting coating solution or a photocurable coating solution.

[0045] In the case of a coating solution for forming a thermosetting coating film, the solution can be prepared by adding a matrix component and, if necessary, a thermosetting curing catalyst or additives to a dispersion containing titanium oxide particles of the present invention. For example, the coating solution can be manufactured according to the description in Japanese Patent Application Publication No. 2000-204301.

[0046] Furthermore, in the case of a coating solution for forming a photocurable coating film, it can be prepared by adding a matrix component and, if necessary, a photocuring catalyst, additives, etc., to a dispersion containing titanium oxide particles of the present invention. For example, the coating solution can be manufactured based on the description in Japanese Patent Application Publication No. 2009-056387.

[0047] Examples of the matrix components that can be used include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltriethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, phenylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane. These may be used individually or in combination of two or more types.

[0048] Examples of thermosetting curing catalysts include amines such as n-butylamine, triethylamine, guanidine, and biguanidide; amino acids such as glycine; metal acetylacetonates such as aluminum acetylacetonate, chromium acetylacetonate, titanyl acetylacetonate, and cobalt acetylacetonate; metal salts of organic acids such as sodium acetate, zinc naphthenate, cobalt naphthenate, zinc octoate, and tin octoate; perchlorates such as perchloric acid, ammonium perchlorate, and magnesium perchlorate, or their salts; acids such as hydrochloric acid, phosphoric acid, nitric acid, and p-toluenesulfonic acid; or metal chlorides such as Lewis acids like SnCl2, AlCl3, FeCl3, TiCl4, ZnCl2, and SbCl3. These may be used individually or in combination of two or more.

[0049] Examples of photocuring catalysts that can be used include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 2-hydroxymethyl-2-methylphenylpropane-1-ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl-ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one. These may be used individually or in combination of two or more.

[0050] Examples of additives that can be used include surfactants, leveling agents, UV absorbers, light stabilizers, diluent solvents, preservatives, antifouling agents, antibacterial agents, defoamers, UV degradation inhibitors, and dyes. These may be used individually or in combination of two or more.

[0051] [Method for manufacturing a substrate coated with titanium dioxide particles] A coated substrate containing titanium oxide particles according to the present invention can be prepared by a conventionally known method using a substrate and the aforementioned coating solution for forming a coating film.

[0052] Examples of substrates include various substrates made of glass or plastic, and a specific example is a plastic substrate used as an optical lens. The thickness of the coating film formed on the substrate varies depending on the application of the coated substrate. However, to obtain coating strength (e.g., evaluation by Bayer test), it is preferable to have a thickness of 0.5 μm or more, more preferably 1 μm or more, and particularly preferable 2 μm or more. The upper limit of the film thickness is not particularly limited, but it may be 100 μm or less, 50 μm or less, or 30 μm or less.

[0053] When preparing a coated substrate containing titanium oxide particles of the present invention using the aforementioned thermosetting coating solution, it can be manufactured, for example, according to the description in Japanese Patent Application Publication No. 2000-204301. Alternatively, when using the aforementioned photocurable coating solution, the coating solution can be manufactured, for example, according to the description in Japanese Patent Application Publication No. 2009-56387. These coating solutions can be prepared by applying them to a substrate using conventionally known methods such as dipping, spraying, spinning, roll coating, or bar coating, drying, and curing by heat treatment or ultraviolet irradiation.

[0054] When manufacturing a coated substrate according to the present invention, the substrate surface may be pre-treated with an alkali, acid, or surfactant, polished with inorganic or organic fine particles, or subjected to primer treatment or plasma treatment in order to improve the adhesion between the substrate, such as a plastic substrate, and the coating film. [Examples]

[0055] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. [Measurement method or evaluation method] Various measurements and evaluations were performed as follows:

[0056] [1] Average particle size The shape of the sample was observed using a scanning electron microscope (SEM) (Hitachi High-Technologies Corporation, S-5500) at an accelerating voltage of 30 kV. The sample for observation was prepared as follows: The aqueous dispersion sol of the sample was diluted with water to a solid content concentration of 0.05 mass%, then coated onto a collodion film-coated metal grid (Oken Shoji Co., Ltd.), and the solvent was evaporated by irradiating it with a 250 W infrared lamp for 30 minutes to prepare the sample for observation. The obtained SEM image was printed, and the particle diameter of 100 primary particles was measured with calipers, and the average value was taken as the average particle diameter. If the particle shape was anisotropic, the longest axis was taken as the particle diameter.

[0057] [2] Solid content concentration After removing the solvent contained in the sample by infrared irradiation or the like, the residue was calcined at 1000°C for 1 hour to obtain the ignition residue (solid content). The ratio of the mass of the ignition residue to the mass of the sample was defined as the solid content concentration.

[0058] [3] Method for measuring particle composition (Titanium, tin, silicon, iron, and antimony) An aqueous dispersion of the sample (inorganic oxide particles such as titanium dioxide particles) was collected in a zirconia crucible, and after removing the water by infrared irradiation, the resulting dried material was heated with Na2O2 and NaOH to melt it. Sulfuric acid and hydrochloric acid were then added to the resulting molten material, and water was added for dilution. Using an ICP instrument (ICPS-8100, manufactured by Shimadzu Corporation), the amounts of titanium, tin, silicon, iron, and antimony in the obtained solution were measured in terms of oxides (TiO2, SnO2, SiO2, Fe2O3, and Sb2O5).

[0059] (Zirconium, molybdenum, aluminum) A water dispersion of the sample was placed in a platinum dish, hydrofluoric acid and sulfuric acid were added and heated, and then water was added to dissolve the inorganic oxide particles. After further dilution with water, the amounts of zirconium, molybdenum, and aluminum were measured in oxide equivalents (ZrO2, MoO3, and Al2O3) using an ICP instrument (Shimadzu Corporation, ICPS-8100). (potassium) An aqueous dispersion of the sample was placed in a platinum dish, hydrofluoric acid and sulfuric acid were added and heated, and hydrochloric acid was added to dissolve the solid components. After further dilution with water, the amount of potassium was measured in oxide equivalent (K2O) using an atomic absorption spectrometer (Hitachi, Ltd., Z-5300).

[0060] [4] Crystal structure analysis of particles A 2g solid weight portion of the aqueous dispersion of the sample was taken and placed in a porcelain crucible (Type B-2). After drying at 110°C for 12 hours, the residue was placed in a desiccator and cooled to room temperature. Next, the residue was mixed with a small amount of strontium titanate (manufactured by Kojun Chemical Laboratory Co., Ltd.) and ground for 15 minutes. Powder X-ray diffraction was then measured using a SmartLab X-ray diffractometer (manufactured by Rigaku Corporation). The obtained diffraction pattern was analyzed using PDXL2 version 2.7.2.0 software to identify peak positions, and the peak (2θ) originating from the (110) plane of the mixed strontium titanate was corrected to 32.374 degrees. The measurement conditions and details of the data analysis are as follows. • Measurement conditions Measurement device: Powder X-ray diffraction analyzer SmartLab (manufactured by Rigaku Corporation) X-ray generator: 9kW open tube (CuKα source, voltage 45kV, current 200mA) Soller / PSC:5.0deg IS length: 10.0mm PSA: None Soller: 5.0deg IS:1 / 2 RS1: 13mm RS2: 20mm Scan step: 0.02deg Scan range: 5-70deg Scan speed: 5deg / min X-ray detector: High-speed one-dimensional X-ray detector (D / TeX Ultra 250) Measurement atmosphere: Under atmospheric pressure Sample stage: Al2O3 sample holder (bottomless) • Data analysis Analysis software: Integrated powder X-ray diffraction analysis software PDXL2 Version 2.7.2.0 (manufactured by Rigaku Corporation) Smoothing: Smoothing using B-Splne (X threshold 1.5) Background removal: Fitting method Kα2 removal: intensity ratio 0.497 Peak search: Second derivative method, σ cut value = 3, σ cut range 0.5~20.0 Profile fitting method: Fitting to measurement data Profile fitting peak shape: Split pseudo-Voigt function

[0061] [5] Evaluation of the photocatalytic activity inhibitory effect of titanium dioxide particles (measurement of fading rate) A solvent was added to the titanium dioxide particle dispersion so that the mass concentration of Ti (in TiO2 equivalent) was 0.335% and the water / methanol ratio was 1 / 1 (mass ratio). Next, the obtained dispersion was mixed with a glycerin solution of sunset yellow FCF dye with a solid content concentration of 0.02% by mass in a mass ratio (mass of dispersion / mass of glycerin solution) of 1 / 3 to prepare a sample, which was placed in a quartz cell measuring 1 mm in depth, 1 cm in width, and 5 cm in height. Then, using an ultraviolet lamp (LUV-6, manufactured by AS ONE) with a selected wavelength range of I-line (wavelength 365 nm), an intensity of 0.4 mW / cm was applied to a 1 cm wide × 5 cm high surface of the quartz cell. 2 The distance was adjusted to achieve a wavelength equivalent to 365 nm, and ultraviolet light was irradiated.

[0062] The absorbance of the above sample at a wavelength of 490 nm before UV irradiation (A0) and the absorbance after n hours of UV irradiation (A0) n The color of the dye was measured using a UV-Vis spectrophotometer (JASCO, V-550), and the fading rate of the dye after 3 hours of UV irradiation (SY fading rate) was calculated using the following formula. Fading rate=(A n -A0) / A0×100(%)

[0063] [6] Method for measuring the film thickness and refractive index of a coating film The reflectance spectra of the coating film and the coated substrate were measured using an optical measuring device (OLYMPUS USPM-RU III), and the film thickness and refractive index of the coating film were calculated.

[0064] [7] Method for measuring particle refractive index Multiple coating films with different ratios of titanium oxide fine particles to matrix were prepared using the method described in

[0105] to

[0110] of Japanese Patent Publication No. 2010-168266. The refractive index of each coating film was determined using the method described above, and the particle refractive index was calculated from these.

[0065] [8] Weather resistance evaluation of thermosetting coatings Weathering tests were conducted on thermosetting coated substrates using a weathering tester (Q-Lab: UV fluorescent lamp type accelerated weathering tester QUV), and the time until cracks were visually observed was evaluated. The weathering test conditions consisted of the following steps 1, 2, and 3, with one cycle (12 hours), and the presence or absence of cracks was visually observed. [Weather resistance test conditions] Step 1: UV irradiation (light source: UVA-340, radiant intensity: 0.70 W / m²) 2 (Temperature: 60℃, Time: 8 hours) Step 2: Condensation (Light source: None, Temperature: 50°C, Time: 4 hours) Step 3: Return to Step 1. [Evaluation Method] • Environment: Below 10 lux Observation method: An LED light was shone from the side onto the substrate with the thermosetting coating, and the presence or absence of cracks was visually observed.

[0066] [9] Evaluation of the amount of coloration of titanium dioxide particles (YI value) Titanium dioxide particles were dispersed in an aqueous solution with a solid content concentration of 5% by mass. This solution was placed in a quartz cell with a path length of 10 mm, and its absorption spectrum was measured using a UV-Vis spectrophotometer (JASCO V-750). The spectrum was then converted to the XYZ color system using the standard illuminant D65. From this XYZ color system, the YI value was calculated using the following formula, following the method for determining the YI value when using the XYZ color system with the standard illuminant D65 as defined in JIS K7373:2006. YI = 100(1.2985X - 1.1335Z) / Y

[0067]

[10] Bayer trial A wear tester BTE (manufactured by COLTS Laboratories) and a haze value measuring device (NDH5000, manufactured by Nippon Denshoku Industries Ltd.) were used to calculate the Bayer value based on the change in haze value between a plastic lens substrate (test piece described later; hereinafter also referred to as "the lens under test") and a reference lens. As the reference lens, a commercially available plastic lens substrate CR-39 (diethylene glycol bisallyl carbonate, using monomer manufactured by PPG, substrate refractive index 1.50) was used. Specifically, the haze value of each lens was first measured, and the initial haze value of the reference lens was defined as D(std0), and the initial haze value of the lens under test as D(test0). Each lens was placed in the pan of the abrasion testing machine described above, and 500g of special sand (Kryptonite β) was filled on top of it. The pan was then vibrated from side to side at 150 times / minute for 4 minutes (600 times in total). The haze value of the lenses after vibration was measured, and the haze value of the reference lens was defined as D(stdf), and the haze value of the lens under test as D(testf). The Bayer test value (R) was calculated using the following formula. R=[D(stdf)-D(std0)] / [D(testf)-D(test0)]

[0068] [Example 1: Preparation of rutile-type titanium dioxide particles] (1) Co-precipitation gel preparation process A white slurry with a pH of 9.5 was prepared by mixing 668 g of an aqueous titanium tetrachloride solution containing 7.75% by mass of Ti (in TiO2 equivalent) (manufactured by Osaka Titanium Technologies Co., Ltd.), 6.03 g of an aqueous ferric chloride solution containing 7.75% by mass of Fe (in Fe2O3 equivalent) (manufactured by Toagosei Co., Ltd., high-grade superferrous iron), 54.7 g of zirconium oxychloride containing 7.75% by mass of Zr (in ZrO2 equivalent) (manufactured by Taiyo Mining Co., Ltd.), and aqueous ammonia solution containing 15% by mass of ammonia (manufactured by Ube Industries, Ltd.). The slurry was then filtered, and the filtrate was washed with water to obtain 560 g of a coprecipitation gel containing Fe, Zr, and Ti with a solid content of 10% by mass.

[0069] (2) Hydrothermal treatment precursor preparation process To 202 g of the coprecipitation gel obtained in the aforementioned process, 347 g of hydrogen peroxide solution containing 35% by mass of hydrogen peroxide (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 1145 g of water were added. The mixture was then stirred at 80°C for 1 hour, and 328 g of water was added to obtain 2020 g of the lysis solution of the coprecipitation gel. This lysis solution was yellow and transparent, with a pH of 8.5, and the average particle size of the particles in the lysis solution (calculated using cumulant analysis from particle size distribution data obtained using dynamic scattering method (ELS-Z, manufactured by Otsuka Electronics Co., Ltd.)) was 25 nm.

[0070] After mixing cation exchange resin (manufactured by Mitsubishi Chemical Corporation) with this dissolving solution (2020 g), 273 g of potassium stannate aqueous solution containing 1% by mass of potassium stannate (manufactured by Showa Chemical Co., Ltd.) in terms of SnO2 was gradually added under stirring.

[0071] After separating the cation exchange resin contained in the obtained dissolving solution, a silica sol containing 0.4% by mass of aluminum (in terms of Al2O3) was obtained (average particle size 16 nm (value obtained using dynamic scattering method), specific surface area 375 m²). 2 A hydrothermal treatment precursor was prepared by mixing 32.5 g of silica (prepared according to the method described in Example 1 "Preparation of silica sol" of Japanese Patent Publication No. 2009-197078) with 508 g of water.

[0072] (3) Hydrothermal treatment process The hydrothermal treatment precursor obtained in the aforementioned process was heated in an autoclave (manufactured by Pressure Glass Industry Co., Ltd., 5 L) at 165°C for 18 hours. This was cooled to room temperature, and the sol-like reaction product was recovered. This reaction product was concentrated using an ultrafiltration membrane apparatus (manufactured by Asahi Kasei Corporation, SIP-1013, SIP-0013) to obtain 270 g of an aqueous dispersion sol with a solid content of 10% by mass.

[0073] The particles contained in the obtained aqueous dispersion sol were titanium oxide particles with a rutile-type crystalline structure, containing iron, zirconium, tin, silicon, aluminum, and potassium. The composition of these titanium oxide particles (Ti content (in TiO2 equivalent), content of added elements (mol %) relative to Ti, Zr / Fe molar ratio), various physical properties, and evaluation results are shown in Table 1. When the content of each element was calculated using iron, zirconium, tin, and silicon as added elements, the results were 0.07 mol% for Fe, 4.0 mol% for Zr, 5.3 mol% for Sn, and 19.7 mol% for Si, respectively.

[0074] [Example 1: Preparation of coating for film formation] To 2.63 kg of an aqueous zirconium oxychloride solution containing 2% by mass of zirconium oxychloride (manufactured by Taiyo Mining Co., Ltd.) in terms of ZrO2, ammonia water containing 15% by mass of ammonia was gradually added under stirring to obtain a slurry with a pH of 8.5. Next, the slurry was filtered, and the resulting solid was washed with water to obtain 526 g of zirconia cake containing 10% by mass of zirconium oxychloride in terms of ZrO2.

[0075] To 20g of the aforementioned cake, 180g of water was added, and then 4.0g of potassium hydroxide granules containing 85% by mass of potassium hydroxide (manufactured by Kanto Chemical Co., Ltd.) was added to make the system alkaline. Then, 40g of hydrogen peroxide solution containing 35% by mass of hydrogen peroxide was added, and the mixture was heated to 50°C to dissolve the cake. Furthermore, 156g of water was added to obtain 400g of an aqueous solution of zirconic acid peroxide containing 0.5% by mass in terms of ZrO2. The pH of this aqueous solution of zirconic acid peroxide was 12.9.

[0076] The aqueous dispersion sol containing titanium dioxide particles obtained in the aforementioned process was diluted with water to prepare 700 g of a sol with a solid content of 2% by mass. 196 g of the aqueous zirconate peroxide solution obtained in the aforementioned process was added to this sol at room temperature and stirred to obtain an aqueous zirconate peroxide solution mixture.

[0077] The aqueous zirconic acid peroxide mixture obtained in the aforementioned process was heat-treated at 60°C for 6 hours and then cooled to room temperature. This was diluted with water to a solid content concentration of 0.1% by mass, and then subjected to hydrothermal treatment in an autoclave at 165°C for 18 hours. After removing the reaction product, it was concentrated using an ultrafiltration membrane apparatus (Asahi Kasei Corporation, SIP-1013, SIP-0013) to obtain 145 g of an aqueous dispersion of zirconia-coated titanium oxide particles with a solid content concentration of 10% by mass.

[0078] 140 g of the aqueous dispersion obtained in the aforementioned process was added under stirring to a methanol solution in which 10.7 g of tetraethoxysilane (manufactured by Tama Chemical Industry Co., Ltd.) was dissolved as a surface treatment agent. Next, the resulting mixture was heated to 50°C for 6 hours, then cooled to room temperature. After that, the dispersion medium in the mixture was replaced from water to methanol using an ultrafiltration membrane apparatus (manufactured by Asahi Kasei Corporation, SIP-0013), and then further concentrated to obtain a methanol dispersion with a solid content of 20% by mass.

[0079] 6.63 g of the methanol dispersion obtained in the aforementioned process was stirred, and 1.97 g of purified water and 3.02 g of γ-glycidoxypropyltrimethoxysilane (manufactured by Momentive Performance Materials Japan LLC) were added. The mixture was then stirred at room temperature for one hour to co-hydrolyze the methanol dispersion and γ-glycidoxypropyltrimethoxysilane.

[0080] Next, 6.92 g of propylene glycol monomethyl ether (manufactured by Dow Chemical Japan Ltd.), 0.071 g of acetylacetone aluminum (manufactured by Kishida Chemical Co., Ltd.), and 0.071 g of a silicone-based surfactant (manufactured by Toray Dow Corning Ltd., L-7001) as a leveling agent were added to this mixture, and the mixture was stirred at room temperature for one hour, after which it was left to stand at room temperature for 48 hours. This prepared a paint for forming a thermosetting coating film.

[0081] [Example 1: Preparation of coated substrate] [Pretreatment of plastic lens substrates] A required number of commercially available plastic lens substrates with a refractive index of 1.60 ("Monomer name: MR-8" manufactured by Mitsui Chemicals, Inc.) were prepared and etched by immersion in an 8% by mass aqueous solution of NaOH maintained at 40°C for 10 minutes. After removal, they were washed with water and thoroughly dried.

[0082] [Preparation of base material with thermosetting coating] The surface of the plastic lens substrate obtained in the aforementioned process was coated with the thermosetting coating paint obtained in the aforementioned process to form a coating film. A spin coating method was used for coating the paint, and the conditions were adjusted so that the film thickness after curing was 2.5 μm. The coating film was heated at 80°C for 10 minutes, and then at 120°C for 1 hour to cure it, and a substrate with a thermosetting coating film was obtained. The evaluation results of this substrate with a thermosetting coating film are shown in Table 1.

[0083] [Example 2] In Example 1, a water-dispersed sol was obtained in the same manner as in the coprecipitation gel preparation step (1) for rutile-type titanium oxide particles, except that 17.7 g of ferric chloride aqueous solution was added. The composition and physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this water-dispersed sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0084] [Example 3] In Example 1, a water-dispersed sol was obtained in the same manner as in the coprecipitation gel preparation step (1) of the rutile-type titanium oxide particle preparation, except that 60.3 g of an aqueous solution of ferric chloride (manufactured by Toagosei Co., Ltd., high-grade superferrous chloride) was added. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this water-dispersed sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0085] [Example 4] In Example 1, a water-dispersed sol was obtained in the same manner as in the coprecipitation gel preparation step (1) of the rutile-type titanium oxide particle preparation, except that 106 g of an aqueous solution of ferric chloride (manufactured by Toagosei Co., Ltd., high-grade superferrous chloride) was added. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this water-dispersed sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0086] [Example 5] In the preparation of the hydrothermal treatment precursor for rutile-type titanium oxide particles (2) in Example 3, an aqueous dispersion sol was obtained in the same manner as in Example 3, except that 205 g of an aqueous potassium stannate solution containing 1% by mass of potassium stannate (manufactured by Showa Chemical Co., Ltd.) on an SnO2 basis was added to the dissolving solution (2020 g). The composition and various physical properties of the particles contained in the obtained aqueous dispersion sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this aqueous dispersion sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0087] [Example 6] In the preparation of the hydrothermal treatment precursor for rutile-type titanium oxide particles (2) in Example 3, an aqueous dispersion sol was obtained in the same manner as in Example 3, except that 410 g of an aqueous potassium stannate solution containing 1% by mass of potassium stannate (manufactured by Showa Chemical Co., Ltd.) on an SnO2 basis was added to the dissolving solution (2020 g). The composition and various physical properties of the particles contained in the obtained aqueous dispersion sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this aqueous dispersion sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0088] [Example 7] In Example 1, a water-dispersed sol was obtained in the same manner as in the co-precipitation gel preparation step (1) of the rutile-type titanium oxide particle preparation, except that the amount of zirconium oxychloride (manufactured by Taiyo Kogyo Co., Ltd.) containing 7.75% by mass of Zr (calculated as ZrO2) was 5.47 g. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this water-dispersed sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0089] [Example 8] In Example 1, a water-dispersed sol was obtained using the same method as in the co-precipitation gel preparation step (1) of the rutile-type titanium oxide particle preparation, except that the amount of zirconium oxychloride (manufactured by Taiyo Kogyo Co., Ltd.) containing 7.75% by mass of Zr (calculated as ZrO2) was set to 9.30 g. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained using the same method as in Example 1, except that this water-dispersed sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0090] [Example 9] In Example 1, a water-dispersed sol was obtained using the same method as in the co-precipitation gel preparation step (1) for rutile-type titanium oxide particle preparation, except that the amount of zirconium oxychloride (manufactured by Taiyo Kogyo Co., Ltd.) containing 7.75% by mass of Zr (calculated as ZrO2) was 27.4 g. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained using the same method as in Example 1 for coating film formation paint preparation and thermosetting coated substrate preparation, except that this water-dispersed sol was used. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0091] [Example 10] In Example 1, a water-dispersed sol was obtained using the same method as in the co-precipitation gel preparation step (1) for rutile-type titanium oxide particle preparation, except that the amount of zirconium oxychloride (manufactured by Taiyo Kogyo Co., Ltd.) containing 7.75% by mass of Zr (calculated as ZrO2) was 82.1 g. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained using the same method as in Example 1 for coating film formation paint preparation and thermosetting coated substrate preparation, except that this water-dispersed sol was used. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0092] [Example 11] In the preparation of the hydrothermal treatment precursor for rutile-type titanium oxide particles (2) in Example 3, an aqueous dispersion sol was obtained in the same manner as in Example 1, except that 1483 g of an aqueous potassium stannate solution containing 1% by mass of potassium stannate (manufactured by Showa Chemical Co., Ltd.) on an SnO2 basis was added to the dissolving solution (809 g). The composition and various physical properties of the particles contained in the obtained aqueous dispersion sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this aqueous dispersion sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0093] [Example 12] In the preparation of the hydrothermal treatment precursor for rutile-type titanium oxide particles (2) in Example 3, an aqueous dispersion sol was obtained in the same manner as in Example 1, except that 1943 g of an aqueous potassium stannate solution containing 1% by mass of potassium stannate (manufactured by Showa Chemical Co., Ltd.) on an SnO2 basis was added to the dissolving solution (353 g). The composition and various physical properties of the particles contained in the obtained aqueous dispersion sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1, except that this aqueous dispersion sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 1.

[0094] [Example 13] Preparation of rutile-type titanium oxide particles in Example 3 (2) In the hydrothermal treatment precursor preparation step, except that the addition amount of silica sol (average particle diameter 16 nm (value obtained by dynamic light scattering method), specific surface area 375 m 2 / g, pH 2.2, solid content concentration 16% by mass: prepared by referring to the method described in Example 1 of "Preparation of silica sol" in JP-A-2009-197078) containing 0.4% by mass of aluminum in terms of Al2O3 is 24.8 g, and then the amount of water added is 388 g, a substrate with a thermosetting coating film was obtained in the same manner. The evaluation results of this substrate with a thermosetting coating film are shown in Table 1.

[0095] [Example 14] Preparation of rutile-type titanium oxide particles in Example 3 (2) In the hydrothermal treatment precursor preparation step, except that the addition amount of silica sol (average particle diameter 16 nm (value obtained by dynamic light scattering method), specific surface area 375 m 2 / g, pH 2.2, solid content concentration 16% by mass: prepared by referring to the method described in Example 1 of "Preparation of silica sol" in JP-A-2009-197078) containing 0.4% by mass of aluminum in terms of Al2O3 is 53.8 g, and then the amount of water added is 841 g, a substrate with a thermosetting coating film was obtained in the same manner. The evaluation results of this substrate with a thermosetting coating film are shown in Table 1.

[0096] [Example 15] Using the thermosetting coating-forming paint obtained in the same manner as in Example 3, a substrate with a thermosetting coating film was obtained in the same manner except that the spin-coating conditions were adjusted so that the film thickness after curing was 0.1 μm. The evaluation results of this substrate with a thermosetting coating film are shown in Table 1.

[0097] [Comparative Example 1] A substrate with a thermosetting coating film was obtained in the same manner except that titanium oxide particles (titanium(IV) oxide, rutile type, -5 μm, 99.9% (manufactured by Fujifilm Wako Pure Chemical Corporation)) were used instead of the titanium oxide particles obtained in Example 1. The evaluation results and the like of these titanium oxide particles and the substrate with a thermosetting coating film are shown in Table 2.

[0098] [Comparative Example ②] In Example 1, a water-dispersed sol was obtained in the same manner as in the coprecipitation gel preparation step (1) for rutile-type titanium oxide particles, except that ferric chloride aqueous solution and zirconium oxychloride were not added. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1 for coating film formation paint preparation and thermosetting coated substrate preparation, except that this water-dispersed sol was used. The evaluation results of this thermosetting coated substrate are shown in Table 2.

[0099] [Comparative Example 3] In Example 1, a water-dispersed sol was obtained in the same manner as in the co-precipitation gel preparation step (1) for rutile-type titanium oxide particles, except that zirconium oxychloride was not added. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained in the same manner as in Example 1 for coating film formation paint preparation and thermosetting coated substrate preparation, except that this water-dispersed sol was used. The evaluation results of this thermosetting coated substrate are shown in Table 2.

[0100] [Comparative Example 4] In Example 1, a water-dispersed sol was obtained using the same method as in the co-precipitation gel preparation step (1) of the rutile-type titanium oxide particle preparation, except that zirconium oxychloride was not added and 177 g of ferric chloride aqueous solution was added. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained using the same method as in Example 1 for coating film formation paint preparation and thermosetting coated substrate preparation, except that this water-dispersed sol was used. The evaluation results of this thermosetting coated substrate are shown in Table 2.

[0101] [Comparative Example 5] In Example 1, a water-dispersed sol was obtained using the same method as in the coprecipitation gel preparation step (1) for rutile-type titanium oxide particle preparation, except that an aqueous solution of ferric chloride (manufactured by Toagosei Co., Ltd., high-grade superferrous chloride) containing 7.75% by mass of Fe (calculated as Fe2O3) was not added. The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained using the same method as in Example 1 for coating film formation paint preparation and thermosetting coated substrate preparation, except that this water-dispersed sol was used. The evaluation results of this thermosetting coated substrate are shown in Table 2.

[0102] [Comparative Example 6] In Example 1, a water-dispersed sol was obtained using the same method as in the coprecipitation gel preparation step (1) of the rutile-type titanium oxide particle preparation, except that 109 g of molybdenum(V) chloride (Fujifilm Wako Pure Chemical Industries, Ltd.) containing 7.75% by mass of Mo (MoO3 equivalent) was added instead of an aqueous solution of ferric chloride (Toagosei Co., Ltd., high-grade superferrous chloride). The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained using the same method as in Example 1, except that this water-dispersed sol was used for the preparation of the coating for coating formation and the preparation of the thermosetting coated substrate. The evaluation results of this thermosetting coated substrate are shown in Table 2.

[0103] [Comparative Example 7] In Example 1, a water-dispersed sol was obtained using the same method as in the coprecipitation gel preparation step (1) for rutile-type titanium oxide particle preparation, except that 13.4 g of antimony(III) chloride was added instead of an aqueous solution of ferric chloride (manufactured by Toagosei Co., Ltd., high-grade superferrous chloride). The composition and various physical properties of the particles contained in the obtained water-dispersed sol, and the evaluation results are shown in Table 1. Furthermore, a thermosetting coated substrate was obtained using the same method as in Example 1 for coating film formation paint preparation and thermosetting coated substrate preparation, except that this water-dispersed sol was used. The evaluation results of this thermosetting coated substrate are shown in Table 2.

[0104] [Table 1]

[0105] [Table 2]

[0106] The interplanar spacing of the (110) planes of titanium oxide particles in Examples 1-6, which contain Fe and Zr, is larger than that of the titanium oxide particles in Comparative Example 1, which do not contain these elements. Furthermore, Comparative Example 3, which is titanium oxide with Fe dissolved in it, has a similar YI value and less discoloration of the coated substrate compared to Examples 1-6, which contain both Fe and Zr dissolved in it, but it has a higher SY fading rate and lower weather resistance of the coated substrate (cracking occurs in a shorter time). Comparing Comparative Example 4, which has an increased Fe content, with Examples 1-6, it has a lower SY fading rate and higher weather resistance of the coated substrate, but it has a higher YI value and more discoloration of the coated substrate. Moreover, Comparative Example 5, which is titanium oxide with Zr dissolved in it, has a lower YI value and less discoloration of the coated substrate compared to Examples 1-6, but it has a higher SY fading rate and lower weather resistance of the coated substrate. Thus, it can be seen that by dissolving both Fe and Zr in titanium oxide particles, a coated substrate with less discoloration and high QUV crack resistance can be obtained. Furthermore, Comparative Example 6, which is titanium oxide with Mo and Zr solid solution, and Comparative Example 7, which is titanium oxide with Sb and Zr solid solution, both exhibited low weather resistance of the coated substrate, suggesting that solid solution of both Fe and Zr is important.

Claims

1. Fe and Zr are in solid solution. The interplanar spacing of the (110) planes obtained by X-ray diffraction measurement is 0.3250 nm or more. The average particle diameter is in the range of 5 nm or more and 50 nm or less. Rutile-type titanium dioxide particles.

2. The Ti content is such that, relative to the total amount of rutile-type titanium dioxide particles, TiO ２ Rutile-type titanium oxide particles according to claim 1, wherein the converted amount is in the range of 40% by mass or more and 90% by mass or less.

3. Rutile-type titanium oxide particles according to claim 1, wherein the Fe content is in the range of 0.01 mol% or more and 5 mol% or less in molar percentage relative to Ti.

4. The rutile-type titanium oxide particles according to claim 1, wherein the Zr content is in the range of 0.1 mol% or more and 15 mol% or less in molar percentage relative to Ti.

5. The rutile-type titanium oxide particles according to claim 1, wherein the Sn content is in the range of 1 mol% or more and 30 mol% or less relative to Ti.

6. Rutile-type titanium oxide particles according to claim 1, wherein the Si content is in the range of 5 mol% or more and 70 mol% or less in molar percentage relative to Ti.

7. Rutile-type titanium oxide particles according to any one of claims 1 to 6, wherein the Zr / Fe molar ratio is 1 or more.

8. A dispersion containing rutile-type titanium dioxide particles as described in claim 1.

9. A coating solution for forming a coating film, comprising rutile-type titanium oxide particles and a matrix-forming component as described in claim 1.

10. A coated substrate containing rutile-type titanium oxide particles as described in claim 1.

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