Compositions containing metal oxide particles that reduce the generation of volatile aldehydes

Abstract

The objective of this invention is to provide a composition that inhibits the formation of aldehyde compounds even through photocatalysis, and a method for manufacturing the same. This composition comprises photoactive metal oxide particles. The solution of this invention is a composition comprising photoactive metal oxide particles (A), a dispersant (B), and an organic solvent (C) other than volatile aldehyde compounds, wherein the proportion of alcohols with 1 to 2 carbon atoms in the composition is 200 ppm or less. In this composition, the photoactive metal oxide particles (A) comprise at least one photoactive metal oxide selected from the group consisting of titanium dioxide, tin oxide, and zirconium oxide, and are metal oxide particles with an average particle size of 5 to 60 nm as determined by dynamic light scattering. The photoactive metal oxide particles (A) contain at least 50 mol% of at least one photoactive metal oxide selected from the group consisting of titanium dioxide, tin oxide, and zirconium oxide in all metal oxides.

Description

Technical Field

[0001] This invention relates to a composition containing metal oxide particles that reduces the generation of volatile aldehydes and a method for manufacturing the same. Prior Technology

[0002] A composition comprising a solvent containing metal oxide particles is used in the fields of coating resins or films. Furthermore, numerous reports indicate that metal oxide particles possess photoactive properties. Titanium oxide particles, tin oxide particles, and zirconium oxide particles are representative examples of photoactive particles. The present invention discloses modified metal oxide colloidal particles (C) formed by using metal oxide colloidal particles as the core and coating the outer surface of the particles with composite oxide colloidal particles, and using at least one metal oxide colloidal particles (A) having a primary particle size of 5 to 60 nm selected from the group consisting of Ti, Fe, Zr, Sn, Ta, Nb, Y, Mo, W, Pb, In, Bi and Sr as the core, and coating the outer surface of the particles with silicon dioxide / tin dioxide composite oxide colloidal particles (B) having a primary particle size of 1 to 4 nm with a molar ratio of M / (SnO 2+SiO 2) (where M represents an amine compound) of silicon dioxide / tin dioxide mass ratio of 0.1 to 5.0 and 0.001 to 0.08. A method for manufacturing nanoparticles is disclosed, characterized by coating the surface of metal or metal oxide nanoparticles with a phosphate-based surfactant (see Patent Document 2). A titanium dioxide dispersion is disclosed, which contains titanium dioxide particles coated with phosphorus-containing oxyacids, (meth)acrylic acid monomers, and phosphorus or sulfur-containing oxyacids (see Patent Document 3). Previous technical documents Patent documents

[0003] Patent Document 1: International Publication No. WO2011 / 090084 Patent Document 2: Japanese Patent Application Publication No. 2010-159464 Patent Document 3: Japanese Patent Application Publication No. 2011-074328 Summary of the Invention

[0004] The problem that the invention aims to solve

[0005] The present invention provides a composition that inhibits the formation of aldehyde compounds even by photocatalysis, and a method for manufacturing the same. The composition comprises photoactive metal oxide particles. Methods for solving problems

[0006] The first aspect of the present invention is a composition comprising photoactive metal oxide particles (A), a dispersant (B), and an organic solvent (C) other than volatile aldehyde compounds, wherein the composition contains an alcohol having 1 to 2 carbon atoms in a proportion of less than 200 ppm. The second viewpoint is the composition as described in the first viewpoint, wherein the aforementioned photoactive metal oxide particles (A) include at least one photoactive metal oxide selected from the group consisting of titanium oxide, tin oxide and zirconium oxide, and are metal oxide particles with an average particle size of 5 to 500 nm as determined by dynamic light scattering. The third viewpoint is the composition as described in the first or second viewpoint, wherein the aforementioned photoactive metal oxide particles (A) are at least one photoactive metal oxide selected from the group consisting of titanium oxide, tin oxide and zirconium oxide, comprising more than 50 mol% of all metal oxides. The fourth viewpoint is the composition described in any of the first to third viewpoints, wherein the aforementioned photoactive metal oxide particle (A) is a metal oxide particle made of photoactive metal oxide, a metal oxide particle containing photoactive metal oxide, or a core-shell type metal oxide particle. The core-shell type metal oxide particle is a core-shell type metal oxide particle whose surface is covered by a coating layer of metal oxide particles with a metal oxide composition or metal oxide content different from that of the core metal oxide. The core metal oxide particle, the coating layer metal oxide particle, or both contain photoactive metal oxide. The fifth viewpoint is the composition as described in the fourth viewpoint, wherein the aforementioned photoactive metal oxide particles (A) are core-shell type metal oxide particles whose surface is covered by metal oxide particles containing silicon dioxide, and the total metal oxide contains more than 50 mol% titanium oxide. The sixth viewpoint is the composition as described in the fourth viewpoint, wherein the metal oxide particles of the aforementioned core are particles of titanium oxide, zirconium oxide, tin oxide, titanium oxide-tin oxide composite oxide, zirconium oxide-tin oxide composite oxide, titanium oxide-zirconia composite oxide, or titanium oxide-zirconia-tin oxide composite oxide. The seventh viewpoint is the composition as described in the fourth viewpoint, wherein the metal oxide particles of the coating layer are at least one type of metal oxide particles or composite metal oxide particles selected from the group consisting of silicon dioxide, tin oxide, antimony oxide, tungsten oxide, aluminum oxide and zirconium oxide. The eighth viewpoint is a composition as described in any of the first to seventh viewpoints, wherein the dispersant (B) is a silane compound, an organic acid or its salt, a phosphate ester or a surfactant. The ninth viewpoint is the composition as described in the eighth viewpoint, wherein the aforementioned silane compound is a silane coupling agent, and the silane coupling agent is at least one silane compound selected from the group consisting of formulas (1) to (3); In formula (1), R1 is each an alkyl, haloalkyl, alkenyl, aryl, or an organic group having a polyether group, epoxy group, (meth)acrylyl group, mercapto group, amino group, urea group, or cyano group and bonded to silicon atoms by a Si-C bond; R2 represents each an alkoxy, acetoxy, or halogroup; and a represents an integer from 1 to 3. In formulas (2) and (3), R3 and R5 are each an alkyl group with 1 to 3 carbon atoms or an aryl group with 6 to 30 carbon atoms bonded to silicon atoms by Si-C bonds, R4 and R6 represent alkoxy, acetoxy, or halogroups, Y represents alkyl, NH, or oxygen atoms, b is an integer from 1 to 3, c is an integer from 0 to 1, and d is an integer from 1 to 3. The 10th viewpoint is the composition as described in the 8th viewpoint, wherein the organic acid is at least one organic acid selected from the group consisting of divalent aliphatic carboxylic acids, aliphatic hydroxycarboxylic acids, amino acids and chelating agents, wherein the divalent aliphatic carboxylic acid is selected from the group consisting of oxalic acid, malonic acid and succinic acid, the aliphatic hydroxycarboxylic acid is selected from the group consisting of glycolic acid, lactic acid, malic acid, tartaric acid and citric acid, the amino acid is selected from the group consisting of glycine, alanine, valine, leucine, serine and threonine, and the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid, L-aspartic-N,N-diacetic acid and diethylenetriaminepentaacetic acid. The 11th view is the composition as described in the 8th view, wherein the phosphate ester is at least one phosphate ester selected from the group consisting of formulas (4) to (6); (In formulas (4) to (6), X1, X2 and X3 each represent an alkyl group with 2 to 20 carbon atoms, f, h and j each represent an integer from 1 to 100, e, g and i each represent an integer from 1 to 3, and Y1, Y2 and Y3 each represent a hydrogen atom, an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms or a (meth)acrylate group). The 12th viewpoint is the composition as described in the 8th viewpoint, wherein the phosphate ester is a polyoxyethylene alkyl (C6-10) ether phosphate ester having alkyl groups having 6 to 10 carbon atoms. The 13th viewpoint is a composition as described in the 8th viewpoint, wherein the aforementioned surfactant is an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant. The 14th viewpoint is a composition as described in any of the 1st to 13th views, wherein the organic solvent (C) is an alcohol, ester, ketone, amide, or hydrocarbon having 3 to 10 carbon atoms and an ether bond. Viewpoint 15 is a composition as described in any of Viewpoints 1 through 14, which further comprises a secondary or tertiary amine having a total carbon number of 5 to 35. The 16th viewpoint is a composition as described in any of the 1st to 15th viewpoints, wherein when 15g of the above composition is irradiated with ultraviolet light of wavelength 365nm at an intensity of 0.4mW / cm² for 4 hours, the volatile aldehyde compounds generated in the composition are less than 2ppm. The 17th viewpoint is a composition as described in any of the 1st to 16th views, wherein the solid content is 0.1 to 70% by mass, and the total solid content contains 80 to 99% by mass of photoactive metal oxide particles (A) and 1 to 20% by mass of dispersant (B). The 18th point is a varnish that further comprises a thermosetting or photosetting resin in the composition described in any of the 1st to 17th points. The 19th point is the varnish described in the 18th point, wherein the varnish is a hardening agent or a filler. The 20th viewpoint is a method for manufacturing an article of the composition described in any of the 1st to 17th views, comprising the following steps (i) and (ii); Step (i): The step (i) of mixing photoactive metal oxide particles (A), dispersant (B), and organic solvent (C) other than volatile aldehyde compounds. Step (ii): Remove the liquid obtained in step (i) until the proportion of alcohols with 1 to 2 carbon atoms in the total solvent is less than 200 ppm. The effects of the invention

[0007] Photoactive metal oxide particles, such as those containing titanium oxide, tin oxide, and zirconium oxide, possess photocatalytic properties, exhibiting the ability to self-reduce and oxidize others. In compositions containing these photoactive metal oxide particles, the particles are dispersed in a solvent. Lower alcohols with 1 to 2 carbon atoms, such as methanol or ethanol, are widely used as solvents. These alcohols oxidize methanol to formaldehyde and ethanol to acetaldehyde through the photocatalytic action of the photoactive metal oxide particles. Formaldehyde and acetaldehyde are volatile aldehyde compounds known to have adverse effects on human health, and their occurrence should be minimized.

[0008] In compositions containing photoactive metal oxide particles, there may be instances where the composition contains dispersants or arbitrary additives. These dispersants or additives may be incorporated into the final product of a product where lower alcohols were used as raw materials or reaction solvents during their manufacture.

[0009] Furthermore, in the manufacture of compositions containing photoactive metal oxide particles, methanol or ethanol may be introduced as a byproduct of the manufacturing process (e.g., hydrolyzed residues of silane coupling agents), or as a cleaning solvent used in the reactors or piping of the manufacturing apparatus, leaving residues, thereby contaminating the aforementioned compositions. Because these compositions contain methanol or ethanol, formaldehyde or acetaldehyde may be produced through the photocatalytic action of the photoactive metal oxide particles.

[0010] The composition of this invention is an organic solvent other than volatile aldehyde compounds. The proportion of alcohols with 1 to 2 carbon atoms in the composition is less than 200 ppm. Therefore, even under visible light or ultraviolet light irradiation, the generation of volatile aldehydes is less than 2 ppm. Moreover, when photoactive metal oxide particles are dispersed in such organic solvents, a composition with highly dispersible photoactive metal oxide particles is obtained by using a specific dispersant containing a specific amount of silane coupling agent, organic acid or its salt, phosphate ester or surfactant. Implementation

[0011] Forms of implementing the invention

[0012] This invention relates to a composition comprising photoactive metal oxide particles (A), a dispersant (B), and an organic solvent (C) other than a volatile aldehyde compound, wherein the composition contains an alcohol having 1 to 2 carbon atoms in a proportion of 200 ppm or less. Preferably, the alcohol having 1 to 2 carbon atoms in the composition is 0.001 to 200 ppm or 0.01 to 100 ppm.

[0013] The aforementioned photoactive metal oxide particles (A) may include at least one photoactive metal oxide selected from the group consisting of titanium oxide, tin oxide and zirconium oxide, and may be metal oxide particles with an average particle size of 5~500 nm, 5~300 nm, 5~250 nm or 5~60 nm as determined by dynamic light scattering method.

[0014] Photoactive metal oxide particles (A) self-reduced through photocatalysis and oxidized others, thus oxidizing the solvent in the composition (e.g., alcohols with 1-2 carbon atoms, i.e., methanol or ethanol) to produce volatile aldehydes (e.g., formaldehyde, acetaldehyde). However, the proportion of photoactive metal oxides in all metal oxides may be 50 mol% or more, or 50-100 mol% of the total. That is, the photoactive metal oxide particles (A) may contain 50 mol% or more of at least one photoactive metal oxide selected from the group consisting of titanium oxide, tin oxide, and zirconium oxide.

[0015] The photoactive metal oxide particle (A) can be defined as a metal oxide particle made of a photoactive metal oxide, a metal oxide particle containing a photoactive metal oxide, or a core-shell type metal oxide particle. Core-shell type metal oxide particles are metal oxide particles whose surfaces are covered by a coating layer that has a different metal oxide composition or content than that of the core metal oxide. The core metal oxide particles, the coating layer metal oxide particles, or both may contain photoactive metal oxides.

[0016] In this specification, the photoactive metal oxide contained in the photoactive metal oxide particle (A) can be in the form of a particle or an aggregate of it (photoactive metal oxide particle (i)). That is, the photoactive metal oxide particle (A) can be defined as a metal oxide particle composed of photoactive metal oxide particles (i), or a metal oxide particle containing photoactive metal oxide particles (i). Furthermore, when the photoactive metal oxide particle (A) is a core-shell type metal oxide particle, the core metal oxide particle, the coating metal oxide particle, or both can be defined as a particle containing photoactive metal oxide particles (i).

[0017] Metal oxide particles composed of photoactive metal oxides are those in which metal oxide particles (A) are composed of only photoactive metal oxides (or photoactive metal oxide particles (i)) at a ratio of 100 mol%.

[0018] Metal oxide particles containing photoactive metal oxide particles are those in which the metal oxide particles (A) contain photoactive metal oxides (or photoactive metal oxide particles (i)) in a proportion of 50 mol% or more but less than 100 mol% of all metal oxides.

[0019] The core-shell type metal oxide particles are coated with a coating layer of metal oxide particles whose metal oxide composition or content is different from that of the core metal oxide particles. The core metal oxide particles, the coating layer metal oxide particles, or both contain photoactive metal oxides (or photoactive metal oxide particles (i)) in a proportion of 50 mol% to 100 mol% in all metal oxides. For example, a photoactive metal oxide particle (A) can be exemplified as a core-shell type metal oxide particle whose surface is covered by a metal oxide particle containing titanium oxide, which forms the core, and contains more than 50 moles of titanium oxide particles in all metal oxides.

[0020] For example, metal oxide particles used for nuclei may include particles comprising titanium oxide, zirconium oxide, tin oxide, titanium oxide-tin oxide composite oxides, zirconium oxide-tin oxide composite oxides, titanium oxide-zirconia composite oxides, or titanium oxide-zirconia-tin oxide composite oxides. These particles, observed by transmission electron microscopy, have an average primary particle size of 5–500 nm, 5–300 nm, 5–250 nm, or 5–60 nm.

[0021] For example, the metal oxide particles contained in the coating layer can be exemplified by at least one type of metal oxide particle or composite metal oxide particle selected from the group consisting of silicon dioxide, tin oxide, antimony oxide, tungsten oxide, aluminum oxide, and zirconium oxide. These particles have an average primary particle size of 1 to 10 nm or 1 to 5 nm, as observed by a transmission electron microscope. Examples of metal oxide particles contained in the coating layer include individual metal oxide particles of silicon dioxide, tin oxide, antimony oxide, tungsten oxide, aluminum oxide, and zirconium oxide, or composite metal oxide particles formed by combining multiple of the above metal oxides. Examples of composite metal oxide particles include tin oxide-silicon dioxide composite metal oxide particles, tin oxide-zirconia-silicon dioxide composite metal oxide particles, tin oxide-tungsten oxide-silicon dioxide composite metal oxide particles, and antimony oxide-silicon dioxide composite metal oxide particles. When the metal oxide particles in the coating include silicon dioxide particles, the ratio of silicon dioxide particles to other metal oxide particles can be set to a ratio of 0.1 to 5.0 by mass ratio of (silicon dioxide) to (other metal oxides).

[0022] When using a core-shell structure, the coating system containing metal oxide particles with different metal oxide compositions or metal oxide contents from the core and the coating layer may include: cases where the metal oxide compositions of the core and the coating layer are different, or cases where even if the metal oxide compositions of the core and the coating layer are partially the same, their metal oxide blending ratios are different. In the case of core-shell structure, the mass ratio of the metal oxide particles of the core to the metal oxide particles of the coating layer can be set to the range of (coating metal oxide particles) / (core metal oxide particles) = 0.05~0.50.

[0023] For example, if we take the tin oxide-silicon dioxide composite oxide contained in the coated metal oxide particles as an example, sodium stannate or potassium stannate can be used as the stannate base, with sodium stannate being preferred. Sodium silicate and potassium silicate can be used as silicate bases. The stanonic acid and silicatic acid system can be prepared by using an aqueous solution containing silicon dioxide / tin dioxide at a mass ratio of 0.1 to 5, followed by removal of cations present in the aqueous solution by a cation exchange resin.

[0024] The stanonic acid base and silicatic acid base are measured in a silicon dioxide / tin dioxide mass ratio of 0.1 to 5.0 and dissolved in water to prepare the solution. The preferred aqueous solution has a solid content concentration of 1 to 12% by mass (SnO2 + SiO2). The prepared aqueous solution is prepared by removing cations using a cation exchange resin. A hydrogen-form, strongly acidic cation exchange resin is preferred as the cation exchange resin, and a column packed with, for example, Amberlite (trade name) 120B can be used in the cation exchange. Through this cation exchange, the silicic acid component and the acid component polymerize to generate silica-tin dioxide composite colloidal particles with a primary particle size of 1 to 4 nm.

[0025] Because this silicon dioxide-tin dioxide composite colloidal particle system lacks stability and gels within hours if left to stand, it is necessary to rapidly add an amine compound after cation exchange to stabilize it. This results in an aqueous sol containing silicon dioxide / tin dioxide colloidal particles with a primary particle size of 1 to 4 nm, stabilized by an amine compound and present in a silicon dioxide / tin dioxide mass ratio of 0.1 to 5.0 and a molar ratio of M / (SnO₂ + SiO₂) of 0.1 to 1.0 (where M represents the amine compound). The resulting aqueous sol is prepared as follows: (SnO₂ + SiO₂) = 0.1 to 10% by mass.

[0026] In the stabilization of silicon dioxide-tin dioxide complex colloidal particles generated by the aforementioned cation exchange, it is appropriate to add an amount of amine compound in the molar ratio of M / (SnO 2+SiO 2) (where M represents the amine compound) of 0.1 to 1.0. When an amine compound with a molar ratio of M / (SnO 2+SiO 2) of 0.1 to less than 1.0 is added, it loses its stability and gels after being left for several hours, therefore this is not advisable.

[0027] Next, by mixing an aqueous sol of metal oxide colloidal particles (a) with a primary particle size of 5 to 60 nm, and an aqueous sol of silicon dioxide-tin dioxide composite oxide colloidal particles (b) with a primary particle size of 1 to 4 nm stabilized by an amine compound at a molar ratio of M / (SnO 2+SiO 2) of 0.1 to 5.0 and 0.1 to 1.0 relative to the aforementioned metal oxide colloidal particles, the mass ratio (b) / (a) of the aforementioned silicon dioxide-tin dioxide composite oxide colloidal particles is 0.05 to 0.50, a modified metal oxide colloidal particle (A) is obtained by coating the aforementioned metal oxide colloidal particles (a) with the aforementioned silicon dioxide-tin dioxide composite oxide colloidal particles (b).

[0028] The concentration of the solid component of the aqueous sol of the aforementioned metal oxide colloidal particles (a) is 0.5 to 50% by mass, preferably 5 to 30% by mass.

[0029] The aqueous sol system of the aforementioned metal oxide colloidal particles (a) can be used with a pH of 5 to 11.5, preferably 7 to 11.5. The pH of the aqueous sol can be adjusted as needed by using an alkaline component. Examples of alkaline components include alkali metal hydroxides such as lithium, sodium, and potassium; alkaline earth metal hydroxides such as calcium, magnesium, and strontium; alkylamines such as ammonia, ethylamine, triethylamine, isopropylamine, and n-propylamine; aralkylamines such as benzylamine; alicyclic amines such as piperidine; alkanolamines such as monoethanolamine and triethanolamine; and quaternary ammonium hydroxides.

[0030] The mixing of the aqueous sol of the aforementioned metal oxide colloidal particles (a) and the aqueous sol of the coated particles (b) is preferably carried out under stirring.

[0031] The mixing ratio of the aforementioned silicon dioxide-tin dioxide composite oxide colloidal particles (b) to the aforementioned metal oxide colloidal particles (a), expressed as a mass ratio (b) / (a), is preferably 0.05 to 0.50. If it is less than 0.05, the metal oxide colloidal particles (a), which serve as nuclei, cannot be sufficiently coated by the silicon dioxide-tin dioxide composite oxide colloidal particles (b), and a stable hydrophilic organic solvent dispersion or a hydrophobic organic solvent dispersion with a water solubility of 0.05 to 12% by mass cannot be obtained. Furthermore, a mass ratio of 0.50 is sufficient; even exceeding 0.50 is inefficient.

[0032] Next, the aqueous sol of the obtained modified metal oxide colloidal particles (A) is subjected to cation exchange, preferably using a hydrogen-form strong acid cation exchange resin.

[0033] Next, in the obtained aqueous sol, an amine compound is added in an amount of M / (SnO 2+SiO 2) (where M represents the amine compound) to a molar ratio relative to the aforementioned silicon dioxide-tin dioxide composite oxide colloidal particles (b) of 0.001 to 0.08. When the molar ratio of M / (SnO 2+SiO 2) is less than 0.001, the dispersion stability of the hydrophilic organic solvent dispersion sol of the present invention becomes insufficient, which is undesirable. Furthermore, when the molar ratio of M / (SnO 2+SiO 2) exceeds 0.08, the bonding of silane compounds bonded to the particle surface of the aforementioned modified metal oxide colloidal particles (A) becomes hindered.

[0034] Next, the aqueous medium of the resulting aqueous sol is replaced with a hydrophilic organic solvent. Methods for replacing the dispersion medium from water with a hydrophilic organic solvent are well-known, including evaporation under normal or reduced pressure, ultrafiltration, and solvent extraction.

[0035] To ensure efficient solvent displacement, the resulting aqueous sol is preferably pre-concentrated to achieve a concentration of 1 to 70% by mass or 10 to 50% by mass of the modified metal oxide colloidal particles (A). Concentration of the sol can be achieved using well-known methods such as heating evaporation or ultrafiltration. The temperature of the sol during solvent displacement can be between room temperature and the boiling point of the hydrophilic solvent. Solvent displacement continues until the water content in the sol reaches less than 5% by mass. The solids concentration of the resulting sol, expressed as the total metal oxide concentration of the aforementioned modified metal oxide colloidal particles (A), is 20 to 70% by mass.

[0036] In this invention, the organic solvent used for solvent replacement is the organic solvent (C) of this invention. The organic solvent (C) contains an alcohol with 1 to 2 carbon atoms in a proportion of less than 200 ppm in the total solvent, and is preferably an organic solvent (C) other than a volatile aldehyde compound. Examples of organic solvent (C) include, for example, alcohols, esters, ketones, amides, or hydrocarbons with 3 to 10 carbon atoms that may have ether bonds.

[0037] Examples of alcohols with 3 to 10 carbon atoms include n-propanol, i-propanol, n-butanol, isobutanol, n-pentanol, ethylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether.

[0038] Examples of ketones include straight-chain or cyclic aliphatic ketones with 3 to 30 carbon atoms, such as methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, diisopropyl ketone, diisobutyl ketone, methyl pentyl ketone, and cyclohexanone.

[0039] Examples of ethers include straight-chain or cyclic aliphatic ethers with 3 to 30 carbon atoms, such as diethyl ether and tetrahydrofuran.

[0040] Examples of esters include straight-chain or cyclic esters with 2 to 30 carbon atoms, such as ethyl acetate, n-butyl acetate, dibutyl acetate, methoxybutyl acetate, amyl acetate, n-propyl acetate, isopropyl acetate, ethyl lactate, butyl lactate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, phenyl acetate, phenyl lactate, and phenyl propionate. Acetamides are aliphatic acetamides with 3 to 30 carbon atoms, such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and N-ethylpyrrolidone.

[0041] As hydrocarbons, examples include straight-chain or cyclic aliphatic or aromatic hydrocarbons with 6 to 30 carbon atoms, such as hexane, heptane, octane, nonane, decane, benzene, toluene, and xylene.

[0042] The composition of the present invention may further include secondary or tertiary amines with a total carbon number of 5 to 35. For example, when the photoactive metal oxide particles (A) contain silicon dioxide particles, the content of the above-mentioned amine can be set to 0.01~10.0 mmol or 0.01~5.0 mmol per 100g of SiO2 of silicon dioxide particles.

[0043] Examples of secondary amines mentioned above include ethyl n-propylamine, ethyl isopropylamine, dipropylamine, diisopropylamine, ethyl butylamine, n-propyl butylamine, dibutylamine, ethyl pentylamine, n-propyl pentylamine, isopropyl pentylamine, dipentylamine, ethyl octylamine, isopropyl octylamine, butyl octylamine, and dioctylamine.

[0044] Examples of the aforementioned tertiary amines include triethylamine, ethyl di-n-propylamine, diethyl di-n-propylamine, tri-n-propylamine, triisopropylamine, ethyl dibutylamine, diethylbutylamine, isopropyl dibutylamine, diisopropyl ethylamine, diisopropyl butylamine, tributylamine, ethyl dipentylamine, diethylpentylamine, tripentylamine, methyl dioctylamine, dimethyl octylamine, ethyl dioctylamine, diethyl octylamine, trioctylamine, benzyl dibutylamine, and diazabicycloundecene.

[0045] Among the above-mentioned amines, secondary and tertiary amines having a total carbon number of 6 to 35 are preferred, such as diisopropylamine, tripentylamine, triisopropylamine, dimethyloctylamine, and trioctylamine.

[0046] The components of this invention, when used as dispersants (B), may include silane compounds, organic acids or their salts, phosphate esters or surfactants.

[0047] Examples of silane compounds include silane coupling agents, such as at least one silane compound selected from the group consisting of formulas (1) to (3). In this invention, photoactive metal oxide particles (A) coated with a hydrolysate of the aforementioned silane compound can be used.

[0048] Adding at least one silane compound selected from the group consisting of formulas (1) to (3) to the obtained hydrophilic organic solvent dispersion and hydrolyzing it can hydrolyze the photoactive metal oxide particles (A) in the sol coated with the hydrolysate.

[0049] In formula (1), R1 is each an alkyl, haloalkyl, alkenyl, aryl, or an organic group having a polyether group, epoxy group, (meth)acrylyl group, mercapto group, amino group, urea group, or cyano group and bonded to silicon atoms by a Si-C bond; R2 represents each an alkoxy, acetoxy, or halogroup; and a represents an integer from 1 to 3. In formulas (2) and (3), R3 and R5 are each an alkyl group with 1 to 3 carbon atoms or an aryl group with 6 to 30 carbon atoms bonded to silicon atoms by Si-C bonds, R4 and R6 represent alkoxy, acetoxy or halogroup respectively, Y represents alkyl, NH or oxygen atom, b is an integer from 1 to 3, c is an integer from 0 or 1, and d is an integer from 1 to 3.

[0050] Examples of alkyl groups with 1 to 18 carbon atoms include methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl, s-butyl, t-butyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, 1-methyl-cyclobutyl, and 2-methyl-cyclobutyl. 3-Methyl-cyclobutyl, 1,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl 1,1,2-Trimethyl-n-propyl, 1,2,2-Trimethyl-n-propyl, 1-Ethyl-1-methyl-n-propyl, 1-Ethyl-2-methyl-n-propyl, Cyclohexyl, 1-Methyl-cyclopentyl, 2-Methyl-cyclopentyl, 3-Methyl-cyclopentyl, 1-Ethyl-cyclobutyl, 2-Ethyl-cyclobutyl, 3-Ethyl-cyclobutyl, 1,2-Dimethyl-cyclobutyl, 1,3-Dimethyl-cyclobutyl, 2,2-Dimethyl-cyclobutyl, 2,3-Dimethyl-cyclobutyl, 2,4-Dimethyl-cyclobutyl, 3,3-Dimethyl-cyclobutyl, 1-n -propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-i-propyl-cyclopropyl, 2-i-propyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl and 2-ethyl-3-methyl-cyclopropyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, decadecyl, hexadecyl, heptadecanyl, heptadecyl, heptadecyl, heptadecyl, octadecyl, etc., but not limited to these. Furthermore, examples of alkyl groups include those derived from the aforementioned alkyl groups.

[0051] Examples of aryl groups include those with 6 to 30 carbon atoms, such as phenyl, naphthyl, anthraceneyl, and pyrene.

[0052] Examples of alkenyl groups include those with 2 to 10 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, 1-methyl-1-vinyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylvinyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-n-propylvinyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2-ethyl-2-propenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, 2-methyl-3-butenyl, etc. -Butenyl, 3-methyl-1-butenyl, 3-methyl-2-butenyl, 3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1-i-propylvinyl, 1,2-dimethyl-1-propenyl, 1,2-dimethyl-2-propenyl, 1-cyclopentenyl, 2-cyclopentenyl, 3-cyclopentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-methyl-1-pentenyl, 1-methyl-2-pentenyl, 1-methyl-3-pentenyl, 1-methyl-4-pentenyl, 1-n-butylvinyl, 2-methyl-1-pentenyl, 2-methyl-2-pentenyl, etc., but not limited thereto.

[0053] Examples of alkoxy groups with 1 to 10 carbon atoms include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, n-pentoxy, 1-methyl-n-butoxy, 2-methyl-n-butoxy, 3-methyl-n-butoxy, 1,1-dimethyl-n-propoxy, 1,2-dimethyl-n-propoxy, 2,2-dimethyl-n-propoxy, 1-ethyl-n-propoxy, n-hexyloxy, etc., but are not limited thereto.

[0054] Examples of acetoxy groups with 2 to 10 carbon atoms include methyl carbonyloxy, ethyl carbonyloxy, n-propyl carbonyloxy, i-propyl carbonyloxy, n-butyl carbonyloxy, i-butyl carbonyloxy, s-butyl carbonyloxy, t-butyl carbonyloxy, n-pentyl carbonyloxy, 1-methyl-n-butyl carbonyloxy, 2-methyl-n-butyl carbonyloxy, 3-methyl-n-butyl carbonyloxy, 1,1-dimethyl-n-propyl carbonyloxy, 1,2-dimethyl-n-propyl carbonyloxy, 2,2-dimethyl-n-propyl carbonyloxy, 1-ethyl-n-propyl carbonyloxy, n-hexyl carbonyloxy, 1-methyl-n-pentyl carbonyloxy, 2-methyl-n-pentyl carbonyloxy, etc., but are not limited thereto.

[0055] Examples of halogen groups include fluorine, chlorine, bromine, and iodine.

[0056] Examples of organic groups containing a polyether group include polyetherpropyl groups containing an alkoxy group. For example, (CH₃O)₃SiC₃H₆(OC₂H₄)nOCH₃ n can be used in the range of 1~100 or 1~10.

[0057] Examples of organic groups with epoxy groups include 2-(3,4-epoxycyclohexyl)ethyl and 3-epoxypropoxypropyl.

[0058] The above-mentioned (meth)acrylic group refers to both acrylonitrile and methacryliconitrile. Examples of organic groups having a (meth)acryliconitrile include 3-methacryloxypropyl and 3-acryloxypropyl.

[0059] Examples of organic groups containing a thiol group include, for instance, 3-mercaptopropyl.

[0060] Examples of organic groups containing an amino group include 2-aminoethyl, 3-aminopropyl, N-2-(aminoethyl)-3-aminopropyl, N-(1,3-dimethyl-butylene)aminopropyl, N-phenyl-3-aminopropyl, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl.

[0061] Examples of organic groups containing a urea group include, for instance, 3-ureopropyl.

[0062] Examples of organic groups containing a cyano group include 3-cyanopropyl.

[0063] The silane compounds shown in formulas (2) and (3) above are preferably compounds that can form trimethylsilyl groups on the surface of silicon dioxide particles. Examples of such compounds include the following. In the above formula, R 12 is an alkoxy group, such as methoxy or ethoxy. The silane compounds described above may be silane compounds manufactured by Shin-Etsu Chemical Co., Ltd.

[0064] The hydroxyl groups on the surface of the silica particles, for example, silica particles, react with the aforementioned silane compounds, thereby coating the silica particles with the silane compounds via siloxane bonds. The reaction can be carried out at temperatures ranging from 20°C to the boiling point of the dispersion medium, for example, from 20°C to 100°C. The reaction can be carried out in approximately 0.1 to 6 hours.

[0065] The aforementioned silane compound is used to coat the surface of silica particles. The amount of silane compound, equivalent to the number of silicon atoms in the silane compound, can be added to the silica sol to coat the surface of the silica particles.

[0066] Water is required for the hydrolysis of the aforementioned silane compounds; however, if the sol is in an aqueous solvent, the water content of that aqueous solvent can be used. Even when the aqueous medium solvent is replaced with an organic solvent (C), the residual water in the solvent can be used. For example, a solvent containing 0.01 to 1% by mass of water can be used. Furthermore, hydrolysis can be carried out using a catalyst or without a catalyst.

[0067] When carried out without a catalyst, an acidic side exists on the surface of the silicon dioxide particles. When a catalyst is used, metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases can be cited as hydrolysis catalysts. Examples of metal chelating compounds that can serve as hydrolysis catalysts include triethoxymono(acetyl acetone)titanium and triethoxymono(acetyl acetone)zirconium. Examples of organic acids that can serve as hydrolysis catalysts include acetic acid and oxalic acid. Examples of inorganic acids that can serve as hydrolysis catalysts include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid. Examples of organic bases that can serve as hydrolysis catalysts include pyridine, pyrrole, piperazine, and quaternary ammonium salts. Examples of inorganic bases that can serve as hydrolysis catalysts include ammonia, sodium hydroxide, and potassium hydroxide.

[0068] The organic acid is at least one organic acid selected from the group consisting of divalent aliphatic carboxylic acids, aliphatic hydroxycarboxylic acids, amino acids, and chelating agents. Examples of divalent aliphatic carboxylic acids include oxalic acid, malonic acid, and succinic acid. Examples of aliphatic hydroxycarboxylic acids include glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid. Examples of amino acids include glycine, alanine, valine, leucine, serine, and threonine. Examples of chelating agents include ethylenediaminetetraacetic acid, L-aspartic-N,N-diacetic acid, and diethylenetriaminepentaacetic acid. Examples of organic acid salts include alkali metal salts, ammonium salts, and amine salts of the above-mentioned organic acids. Examples of alkali metals include sodium and potassium.

[0069] As a phosphate ester, at least one phosphate ester compound selected from the group consisting of formulas (4) to (6) can be cited. In formulas (4) to (6), X1, X2 and X3 each represent an alkyl group with 2 to 20 carbon atoms, f, h and j each represent an integer from 1 to 100, e, g and i each represent an integer from 1 to 3, and Y1, Y2 and Y3 each represent a hydrogen atom, an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms or a (meth)acrylate group.

[0070] As a phosphate ester, polyoxyethylene alkyl ether phosphate ester is more suitable. For example, the phosphate ester mentioned above can be a phosphate ester in which the terminal alkyl group (Y1) in the above formula (4) represents an alkyl group with 6 to 10 or 12 to 15 carbon atoms. Such products can be, for example, Phosphhanol RA-600 and RS-610 manufactured by Toho Chemical Industry Co., Ltd.

[0071] Anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants can be used as surfactants.

[0072] Examples of anionic surfactants used in this invention include sodium and potassium salts of fatty acids, alkylbenzene sulfonates, higher alcohol sulfates, polyoxyethylene alkyl ether sulfates, α-sulfonyl fatty acid esters, α-olefin sulfonates, monoalkyl phosphates, and alkyl sulfonates.

[0073] For example, as alkylbenzene sulfonates, sodium salts, potassium salts, and lithium salts can be cited, such as C10~C16 alkylbenzene sulfonate sodium, C10~C16 alkylbenzene sulfonic acid, alkylnaphthalene sulfonate sodium, etc.

[0074] Examples of higher alcohol sulfate salts include sodium dodecyl sulfate (sodium lauryl sulfate), triethanolamine lauryl sulfate, and triethanolamine lauryl sulfate, which have 12 carbon atoms.

[0075] Examples of polyoxyethylene alkyl ether sulfates include sodium polyoxyethylene styrene phenyl ether sulfate, sodium polyoxyethylene styrene phenyl ether sulfate, sodium polyoxyethylene decyl ether sulfate, sodium polyoxyethylene decyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene tridecyl ether sulfate, and sodium polyoxyethylene oleyl cetyl ether sulfate.

[0076] Examples of α-olefin sulfonates include sodium α-olefin sulfonate.

[0077] Examples of alkyl sulfonates include sodium 2-ethylhexyl sulfate.

[0078] Examples of cationic surfactants used in this invention include alkyl trimethylammonium salts, dialkyl dimethylammonium salts, alkyl dimethyl benzylammonium salts, and amine salts.

[0079] Alkyltrimethylammonium salts are quaternary ammonium salts, possessing chloride or bromide ions as their relative ions. Examples include dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, cocoyltrimethylammonium chloride, and alkyl(C16-18)trimethylammonium chloride.

[0080] Dialkyl dimethyl ammonium salts are those with two lipophilic main chains and two methyl groups. Examples include bis(hydrogenated tallow) dimethyl ammonium chloride. Examples include dialcyl dimethyl ammonium chloride, dicocoyl dimethyl ammonium chloride, dihydrotallowed tallow alkyl dimethyl ammonium chloride, and dialkyl (C14-18) dimethyl ammonium chloride.

[0081] Alkyl dimethyl benzyl ammonium salts are quaternary ammonium salts having a lipophilic main chain of 1 main chain, 2 methyl groups, and 1 benzyl group. Examples include benzyl alkyl ammonium chloride and alkyl (C8-18) dimethyl benzyl ammonium chloride.

[0082] Amine salts are those in which the hydrogen atom of ammonia is replaced by one or more hydrocarbon groups, such as N-methyldihydroxyethylamine fatty acid ester hydrochloride.

[0083] Examples of amphoteric surfactants used in this invention include N-alkyl-β-propanetic acid type alkylamine fatty acid salts, alkyl carboxybetaine type alkyl betaines, and N,N-dimethyldodecylamine oxide type alkylamine oxides. Examples of these include lauryl betaine, stearyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, and lauryl dimethylamine oxide.

[0084] Examples of nonionic surfactants used in this invention include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, alkyl glucosides, polyoxyethylene fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and fatty acid alkanolamides. For example, examples of polyoxyethylene alkyl ethers include polyoxyethylene dodecyl ether (polyoxyethylene lauryl ether), polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene oil-based ether, polyoxyethylene stearyl ether, polyoxyethylene dodecyl ether, polyoxyethylene-2-ethylhexyl ether, and polyoxyethylene isodecyl ether.

[0085] Examples of polyoxyethylene alkylphenol ethers include polyoxyethylene styrene phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene styrene phenyl ether, and polyoxyethylene tribenzylphenyl ether.

[0086] Examples of alkyl glucosides include decyl glucoside and lauryl glucoside.

[0087] Examples of polyoxyethylene fatty acid esters include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol dioleate, and polypropylene glycol dioleate.

[0088] Examples of sorbitan fatty acid esters include sorbitan monocaprylate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan monosesquioleate, and their ethylene oxide adducts.

[0089] Examples of polyoxyethylene sorbitan fatty acid esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan triisostearate.

[0090] Furthermore, examples of fatty acid alkyl alcohol amines include coconut oil fatty acid diethanolamine, tallow fatty acid diethanolamine, lauric acid diethanolamine, and oleic acid diethanolamine.

[0091] Furthermore, examples of surfactants include polyoxyethylene polyoxypropylene glycol, polyoxyethylene fatty acid esters and other polyoxyalkyl ethers or polyoxyalkyl glycols, polyoxyethylene hardened castor oil ether, sorbitan fatty acid ester alkyl ether, alkyl polyglucoside, sorbitan monooleate, sucrose fatty acid ester, etc.

[0092] The method for manufacturing the above-mentioned components of the present invention includes the following steps (i) and (ii); Step (i): The step (i) of mixing photoactive metal oxide particles (A), dispersant (B), and organic solvent (C) other than volatile aldehyde compounds. Step (ii): Remove the liquid obtained in step (i) until the proportion of alcohols with 1 to 2 carbon atoms in the total solvent is less than 200 ppm. The removal of alcohols with 1 to 2 carbon atoms can be carried out, for example, by evaporation or ultrafiltration.

[0093] The composition obtained by the above manufacturing method has a solid content of 0.1 to 70% by mass, and the total solid content can be set to 80 to 99% by mass of photoactive metal oxide particles (A) and 1 to 20% by mass of dispersant (B). Here, solid component refers to the component after removing the solvent component from the composition, and solid component concentration refers to the concentration of solid component in the composition.

[0094] Furthermore, when 15g of the above composition is irradiated with ultraviolet light at an intensity of 0.4mW / cm² for 4 hours at a wavelength of 365nm, the amount of volatile aldehyde compounds generated in the composition is less than 2ppm. Preferably, the amount of the above volatile aldehyde compounds is 0.001~2ppm or 0.01~1ppm.

[0095] If the composition is stored in a brown container, the photocatalytic effect can be reduced. However, with conventional compositions, there are problems with the generation of volatile aldehyde compounds through photocatalytic action when stored in transparent containers, or when the composition is transferred from the container to the device for use, or when it is coated on a substrate.

[0096] However, the composition of the present invention suppresses the generation of volatile aldehydes by setting the proportion of alcohols with 1 to 2 carbon atoms in the composition to 200 ppm or less. Furthermore, in order to disperse photoactive metal oxide particles (A) in an organic solvent (C) having the above characteristics, a dispersant (B) is required.

[0097] The components of this invention can be further mixed with thermosetting or photosetting resins to produce varnishes.

[0098] Furthermore, varnishes containing curing agents such as amine-based curing agents, anhydride-based curing agents, or acid-generating curing agents (thermal acid generators or photoacid generators) can be cured. By applying or filling a substrate with a varnish containing this composition, resin, and curing agent, a cured product can be formed by heating, light irradiation, or a combination thereof. Examples of curable resins include those with functional groups such as epoxy or (meth)acrylic groups.

[0099] In the case of thermosetting varnishes, the thermosetting agent may be contained in a proportion of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, relative to the epoxy or (meth)acrylic functional groups of the resin. The equivalent of the thermosetting agent relative to the curing resin is expressed as the equivalent ratio of the thermosetting agent relative to the functional groups.

[0100] Examples of thermosetting agents include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polythiols, acid anhydrides, and thermosetting acid generators. Acid anhydride-based and amine-based curing agents are particularly preferred. These thermosetting agents can be solid or dissolved in a solvent. However, in order to prevent the density of the hardened material from decreasing due to solvent evaporation or the strength and water resistance of the hardened material from decreasing due to the formation of pores, the hardener itself is preferably liquid at room temperature and pressure.

[0101] Examples of phenolic resins include phenolic varnish resin and cresol varnish resin.

[0102] Examples of amine-based curing agents include piperidine, N,N-dimethylpiperidine, triethylenediamine, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperidine, di(1-methyl-2-aminocyclohexyl)methane, menthene diamine, isophorone diamine, diaminodicyclohexylmethane, 1,3-diaminomethylcyclohexane, xylene diamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and diethyltoluene diamine. Among these, liquid forms of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, menthene diamine, isophorone diamine, diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and diethyltoluene diamine are more suitable.

[0103] Polyamide resins are produced by the condensation of dimer acids and polyamines, and are polyamides that contain both primary and secondary amines in their molecules.

[0104] Examples of imidazole derivatives include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecapridinium trimellitate, and epoxide imidazole adducts.

[0105] Examples of polythiols include those with thiol groups at the ends of polypropylene glycol chains or polyethylene glycol chains, preferably in liquid form.

[0106] As an anhydride-based curing agent, anhydrides of compounds having several carboxyl groups in one molecule are preferred. Examples of such anhydride-based curing agents include phthalic anhydride, trimellitic anhydride, benzopyrene tetracarboxylic anhydride, ethylene glycol dipremetyl phthalate, glycerol trimellitic phthalate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylmethylenetetrahydrophthalic anhydride, methylmethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylcyclohexene dicarboxylic anhydride, and chlorosuccinic anhydride.

[0107] Examples of hot acid generating agents include strontium salts and phosphonium salts, with strontium salts being more suitable. Examples of such compounds include the following. In the formula, R represents an alkyl group with 1 to 12 carbon atoms, an aryl group with 6 to 20 carbon atoms, and preferably an alkyl group with 1 to 12 carbon atoms.

[0108] Among these, the preferred are liquid methyltetrahydrophthalic anhydride, methyl-5-norbornen-2,3-dicarboxylic anhydride (methylnadic anhydride, methylnorbornen anhydride), hydrogenated methylnadic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, methylhexahydrophthalic anhydride, and mixtures of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride. The viscosity of these liquid anhydrides is approximately 10 mPas to 1000 mPas when measured at 25°C.

[0109] Furthermore, when obtaining the above-mentioned cured material, a curing aid may be appropriately used in conjunction. Examples of curing aids include organophosphorus compounds such as triphenylphosphine or tributylphosphine, quaternary phosphine salts such as ethyltriphenylphosphine bromide and diethyl methyltriphenylphosphine phosphate, quaternary ammonium salts such as 1,8-diazabicyclo(5,4,0)undec-7-ene, 1,8-diazabicyclo(5,4,0)undec-7-ene and octanoic acid salts, zinc octanoate, and tetrabutylammonium bromide. These curing aids may be contained in a ratio of 0.001 to 0.1 parts by mass relative to 1 part by mass of the curing agent.

[0110] A thermosetting varnish is obtained by mixing the components, resin, hardener, and desired curing aids. This mixing can be carried out in a reaction vessel using stirring blades or a kneader.

[0111] The mixing process is carried out by heating and mixing at a temperature of 60°C to 100°C for 0.5 to 1 hour.

[0112] The resulting curable resin varnish (thermosetting composition) is a thermosetting coating composition with a suitable viscosity, for example, for use as a liquid sealant. The liquid thermosetting varnish can be formulated to any viscosity, allowing for partial sealing of any part of LEDs and similar components by means of casting, potting, dispensing, printing, etc. After directly applying the liquid thermosetting composition to LEDs or similar components in liquid form using the above method, a cured epoxy resin body is obtained by drying and curing.

[0113] A thermosetting varnish (a thermosetting coating composition) is applied to a substrate and then heated at a temperature of 80 to 200°C to obtain a cured product.

[0114] In the case of photocurable varnishes, a photocuring agent (photoacid generator) may be contained in a proportion of 0.5 to 20% by mass, preferably 0.8 to 10% by mass, relative to the functional groups such as epoxy groups or (meth)acrylic groups in the resin.

[0115] If the photoacid generator is one that produces acid directly or indirectly due to light irradiation, then there are no special limitations.

[0116] Specific examples of photoacid generators include triterpenoid compounds, anthraquinone derivatives, diazonium compounds, diazomethane compounds, sulfonic acid derivatives, iodonium salts, strontium salts, phosphonium salts, selenium salts, metallocene complexes, and iron aromatic hydrocarbon complexes.

[0117] Examples of ononium salts used as photoacid generators include iodonium salts such as diphenyliodonium chloride, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium methanesulfonate, diphenyliodonium toluenesulfonate, diphenyliodonium bromide, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsenate, bis(p-tert-butylphenyl)iodonium hexafluorophosphate, bis(p-tert-butylphenyl)iodonium methanesulfonate, bis(p-tert-butylphenyl)iodonium toluenesulfonate, bis(p-tert-butylphenyl)iodonium trifluoromethanesulfonate, and bis(p-tert-butylphenyl)iodonium... Onion tetrafluoroborate, bis(p-tert-butylphenyl)iodonium chloride, bis(p-chlorophenyl)iodonium chloride, bis(p-chlorophenyl)iodonium tetrafluoroborate, and further bis(4-tert-butylphenyl)iodonium hexafluorophosphate, etc., bis(alkylphenyl)iodonium salts, alkoxycarbonylalkoxy-trialkylaryl iodonium salts (e.g., 4-[(1-ethoxycarbonyl-ethoxy)phenyl]-(2,4,6-trimethylphenyl)-iodonium hexafluorophosphate, etc.), bis(alkoxyaryl)iodonium salts (e.g., bis(alkoxyphenyl)iodonium salts, such as (4-methoxyphenyl)phenyliodonium hexafluoroantimonate).

[0118] Examples of strontium salts include triphenylstrontium chloride, triphenylstrontium bromide, tri(p-methoxyphenyl)strontium tetrafluoroborate, tri(p-methoxyphenyl)strontium hexafluorophosphonate, tri(p-ethoxyphenyl)strontium tetrafluoroborate, triphenylstrontium trifluoromethanesulfonate, triphenylstrontium hexafluoroantimonate, triphenylstrontium hexafluorophosphate, etc.; or (4-phenylthiophenyl)diphenylstrontium hexafluoroantimonate, (4-phenylthiophenyl)diphenylstrontium hexafluorophosphate, bis[4-(diphenylstrontium)phenyl]sulfide-bis-hexafluoroantimonate, bis[4-(diphenylstrontium)phenyl]sulfide-bis-hexafluorophosphate, (4-methoxyphenyl)diphenylstrontium hexafluoroantimonate, etc.

[0119] Examples of phosphonium salts include triphenylphosphonium chloride, triphenylphosphonium bromide, tri(p-methoxyphenyl)phosphonium tetrafluoroborate, tri(p-methoxyphenyl)phosphonium hexafluorophosphonate, tri(p-ethoxyphenyl)phosphonium tetrafluoroborate, 4-chlorobenzyldiaza-onium hexafluorophosphate, and benzyltriphenylphosphonium hexafluoroantimonate.

[0120] Examples of selenium salts include triphenylselenohexafluorophosphate, and metallocene complexes include (η5 or η6-isopropylbenzene)(η5-cyclopentadienyl)iron(II)hexafluorophosphate.

[0121] Furthermore, the following compounds can also be used as photoacid generators.

[0122] As photoacid generators, strontium salt compounds and iodonium salt compounds are preferred. Examples of their anionic species include CF₃SO₃⁻, C₄F₉SO₃⁻, C₈F₁₇SO₃⁻, camphorsulfonate anion, p-toluenesulfonate anion, BF₄⁻, PF₆⁻, AsF₆⁻, and SbF₆⁻. In particular, anionic species such as phosphorus hexafluoride and antimony hexafluoride, which exhibit strong acidity, are preferred.

[0123] The components and varnishes of this invention may include conventional additives as needed. Examples of such additives include, for instance, pigments, colorants, thickeners, sensitizers, defoamers, leveling agents, coatability improvers, lubricants, stabilizers (antioxidants, heat stabilizers, light stabilizers, etc.), plasticizers, solubilizers, fillers, antistatic agents, etc. These additives may be used alone or in combination of two or more.

[0124] Examples of components of this invention and methods for applying varnish include flow coating, spin coating, spray coating, screen printing, casting, rod coating, curtain coating, roller coating, gravure coating, immersion coating, and slot coating.

[0125] In this invention, a photocoating composition can be coated onto a substrate and hardened by light irradiation. Furthermore, heating can be applied before and after light irradiation.

[0126] The thickness of the coating can be selected from approximately 0.01μm to 10mm depending on the intended use of the cured material. For example, when used for photoresist, it can be set to approximately 0.05 to 10μm (especially 0.1 to 5μm); when used for printed wiring boards, it can be set to approximately 5μm to 5mm (especially 100μm to 1mm); and when used for optical films, it can be set to approximately 0.1 to 100μm (especially 0.3 to 50μm).

[0127] The light used for irradiation or exposure when using a photoacid generator can be, for example, gamma rays, X-rays, ultraviolet light, or visible light, but is usually visible light or ultraviolet light, especially ultraviolet light. The wavelength of the light is, for example, 150~800nm, preferably 150~600nm, more preferably 200~400nm, and especially around 300~400nm. The amount of irradiated light varies depending on the thickness of the coating, but can be set to, for example, 2~20000mJ / cm², preferably around 5~5000mJ / cm². The light source can be selected according to the type of light being exposed; for example, in the case of ultraviolet light, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, deuterium lamps, halogen lamps, laser light (helium-cadmium lasers, excimer lasers, etc.) can be used. Under such light irradiation, the curing reaction of the aforementioned components proceeds.

[0128] When using a heat-generating agent, or after irradiation with a photo-generating agent, the coating may be heated as needed, at a temperature of, for example, 60-250°C, preferably around 100-200°C. The heating time can be selected from a range of more than 3 seconds (e.g., 3 seconds to about 5 hours), for example, 5 seconds to 2 hours, preferably around 20 seconds to 30 minutes, and usually around 1 minute to 3 hours (e.g., 5 minutes to 2.5 hours).

[0129] Furthermore, when forming patterns or images (e.g., when manufacturing printed wiring boards), the coating film formed on the substrate can be pattern-exposed. This pattern exposure can be performed by scanning with laser light or by irradiating with light through a photomask. The unexposed areas (unexposed parts) generated by such pattern exposure are then developed (or dissolved) with a developer to form patterns or images.

[0130] As a developing solution, an alkaline aqueous solution or an organic solvent can be used.

[0131] Examples of alkaline aqueous solutions include aqueous solutions of alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, potassium carbonate, and sodium carbonate; aqueous solutions of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetraammonium hydroxide such as choline; and aqueous solutions of amines such as ethanolamine, propylamine, and ethylenediamine.

[0132] The aforementioned alkaline developing solution is generally an aqueous solution of less than 10% by mass, preferably an aqueous solution of 0.1% to 3.0% by mass. Alternatively, alcohols or surfactants can be added to the developing solution, preferably 0.05 to 10 parts by mass of each relative to 100 parts by mass of the developing solution. One of the methods is to use a 0.1-2.38% (w / w) aqueous solution of tetramethylammonium hydroxide.

[0133] Furthermore, common organic solvents can be used as the developing solution, such as acetone, acetonitrile, toluene, dimethylformamide, methanol, ethanol, isopropanol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol butyl ether acetate, ethyl lactate, cyclohexanone, etc., and mixtures of one or more of these solvents can be used. In particular, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl lactate, etc., are preferred.

[0134] In this invention, to improve adhesion to the substrate after development, an adhesion promoter can be added to the varnish. Examples of such adhesion promoters include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; hexamethyldisilazane; N,N'-bis(trimethylsilyl)urea; dimethyltrimethylsilylamine; trimethylsilylimidazolium; vinyltrichlorosilane; and γ-silyl... Silanes such as γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-epoxypropoxypropyltrimethoxysilane, and γ-(N-piperidinyl)propyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzothiazole, urea, thiouracil, mercaptoimidazole, and mercaptopyrimidine; or urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. One or more of the aforementioned adhesion promoters can be used in combination. The amount of these adhesion promoters added is typically 18% by mass or less in the solid component, preferably 0.0008-9% by mass, and more preferably 0.04-9% by mass.

[0135] The composition and varnish of this invention may also contain sensitizers. Examples of usable sensitizers include anthracene, phenanthrene, perylene, thioxanthone, and benzophenone-thioxanthone. Furthermore, examples of sensitizing pigments include thiopyranium salt pigments, anthocyanin pigments, quinoline pigments, styrylquinoline pigments, ketocumarin pigments, thioxanthracene pigments, xanthanium pigments, cyanide pigments, anthocyanin pigments, rose red pigments, and pyranium salt pigments. Anthracene-based sensitizers are particularly preferred, as their sensitivity is significantly enhanced when used in conjunction with cationic curing catalysts (radiosensitive cationic polymerization initiators), while also possessing free radical polymerization initiation capabilities. In hybrid systems combining the cationic curing system and the free radical curing system of this invention, the types of catalysts can be simplified. Specific anthracene compounds include dibutoxyanthracene and dipropoxyanthraquinone. The sensitizer is added at a ratio of 0.01 to 20% by mass, preferably 0.01 to 10% by mass, in the solid component.

[0136] The varnish of this invention can be photocured or thermocured using a photoacid generator or a thermal acid generator. Because a photoacid generator or a thermal acid generator is used instead of commonly used epoxy curing agents (such as amines or acid anhydrides), or even if they are used, in very small amounts, the storage stability of this varnish is improved.

[0137] The aforementioned varnishes are suitable for photocationically polymerizable resins. They exhibit a higher curing speed than conventional liquid epoxy compounds (e.g., alicyclic epoxy compounds with an epoxy cyclohexyl ring). Due to the rapid curing speed, the amount of acid-generating agent added can be reduced, or weak acid-generating agents can be used. Reducing the amount of acid-generating agent is important because acid-active species can remain even after UV irradiation, which is crucial for preventing metal corrosion. Thick film curing is also possible due to the rapid curing speed.

[0138] UV-induced hardening systems can be applied to heat-sensitive materials (mechanical materials).

[0139] The thermosetting and photocuring materials containing epoxy compounds used in this invention possess characteristics such as rapid hardening, transparency, and low curing shrinkage, and can be used for coating or bonding electronic components, optical components, and precision mechanical parts. For example, they can be used for bonding lenses in mobile phones or cameras, optical components such as light-emitting diodes (LEDs) and semiconductor lasers (LDs), liquid crystal panels, biochips, camera lenses or prisms, magnetic components of hard drives in personal computers, the pickup (the part that inputs light information reflected from the disc) in CD and DVD players, the cone and coil of speakers, magnets in motors, circuit boards, electronic components, and internal parts of automobile engines.

[0140] As a hard coating material for surface protection of automobile bodies, lights or electrical products, building materials, plastics, etc., it can be used for automobile and motorcycle bodies, headlight lenses or reflectors, plastic lenses for eyeglasses, mobile phones, game consoles, optical films, ID cards, etc.

[0141] Examples of ink materials for printing on metals such as aluminum and plastics include inks suitable for cards such as credit cards and membership cards, switches for electronic products or OA machines, inks for printing on keyboards, and inks for inkjet printers for CDs and DVDs.

[0142] Examples of its applications include combining with 3D CAD to harden resin and create complex three-dimensional objects, as well as optical modeling for industrial products. It is also applicable to fiber optic coating, bonding, waveguides, and thick-film resists.

[0143] Furthermore, the hardened body forming composition containing the components of the present invention is an insulating resin for electronic materials that can be used as semiconductor sealing materials, adhesives for electronic materials, printed wiring board materials, interlayer insulating film materials, sealing materials for power modules, etc., or an insulating resin used in high-voltage machines such as generator coils, transformer coils, and gas-insulated switching devices.

[0144] Furthermore, examples of the components of the present invention are given, but the present invention is not limited thereto. For example, the present invention provides a sol comprising titanium oxide particles having a quaternary ammonium ion / titanium atom molar ratio of 0.1 to 1.5, an amino acid / titanium atom molar ratio of 0.1 to 1.5, and an average particle size of 5 to 500 nm and photoactivity. The aforementioned average particle size can be obtained by dynamic light scattering.

[0145] Because quaternary ammonium ions coexist with amino acids, titanium dioxide particles can exist stably, especially in sols containing titanium dioxide particles with an average particle size exceeding 100 nm as determined by dynamic light scattering, such as those with particle sizes of 100–500 nm, 110–300 nm, or 110–250 nm.

[0146] Examples of titanium oxide raw materials contained in the above-mentioned sol include titanium oxide particles produced by pulverization, titanium oxide particles produced by hydrolysis of titanium sulfate or titanium oxysulfate, titanium oxide particles produced by polymers of titanium hydroxide, and titanium oxide particles produced by hydrolysis and condensation of alkoxy titanium.

[0147] A sol containing the aforementioned titanium dioxide particles is a core-shell type metal oxide particle sol, with the titanium dioxide particles serving as the core and the surface coated with metal oxide particles containing silicon dioxide. This sol contains titanium dioxide particles containing 50 mol% to 99 mol% of titanium dioxide in all metal oxides. By coating the surface of the core titanium dioxide particles, the photoactivity of titanium dioxide can be suppressed. Titanium dioxide particles containing 50 mol% to 99 mol% of titanium dioxide in all metal oxides are suitable for this purpose. The metal oxide particles used for coating can be at least one type of metal oxide particle or a composite metal oxide particle selected from the group consisting of silicon dioxide, tin oxide, antimony oxide, tungsten oxide, aluminum oxide, and zirconium oxide. The coating ratio can be as described above.

[0148] As the aforementioned quaternary ammonium ion, those based on tetramethylammonium hydroxide or tetraethylammonium hydroxide are suitable. Using a water-soluble alkaline substance can help promote the hydrolysis of the raw material or improve the dispersibility of the resulting titanium dioxide particles.

[0149] As the aforementioned amino acids, glycine, alanine, valine, n-valine, leucine, n-leucine, isoleucine, phenylalanine, tyrosine, diiodotyrosine, N-methyltyrosine, threonine, serine, proline, hydroxyproline, tryptophan, thyroxine, methionine, cystine, cysteine, α-aminobutyric acid, aspartic acid, glutamic acid, aspartamine, glutamic acid, lysine, hydroxylysine, arginine, or histamine can be used, with glycine being particularly useful. These amino acids are water-soluble and, in coordination with quaternary ammonium ions, contribute to the dispersion stability of titanium dioxide particles during their formation. Therefore, they promote the growth of titanium dioxide particles, forming large-diameter titanium dioxide particles, resulting in a stable and dispersed titanium dioxide sol.

[0150] The sol containing the above-mentioned titanium dioxide can be manufactured by hydrothermal reaction of an aqueous medium containing titanium compounds, quaternary ammonium hydroxide and amino acids at 100~300°C.

[0151] The above-mentioned hydrothermal reaction system can be heated for about 0.1 to 10 hours using an autoclave. Furthermore, pre-stirring can be performed at a temperature of around 60 to 100°C before hydrothermal treatment. Example

[0152] The physical properties of the constituents are determined by the following measurement methods. [Viscosity] Measured using an Oswald viscometer (25°C). [Moisture content] was determined by Carl Fischer titration. [Average particle size determined by dynamic light scattering (dynamic light scattering particle size)] The composition was diluted with a dispersing solvent, and the parameters of the solvent were used for determination by dynamic light scattering. Apparatus: ZETASIZER, Malvern Instruments Ltd.

[0153] The amounts of methanol and formaldehyde in the compositions obtained in the examples and comparative examples were determined and evaluated using the methods shown below.

[0154] (1) Methanol quantity The amount of methanol in the composition was determined using a gas chromatography system (Shimadzu GC-2014) under the following conditions. Column: 3mm × 1m glass column Filler: Porapak Q Column temperature: 130~230℃ (heating rate 8℃ / min) Carrier: N 240mL / min Detector: FID Injection volume: 1μL Internal Standard: Acetonitrile

[0155] (2) Formaldehyde content After separating the particles from the solvent by centrifugal ultrafiltration, the solvent was diluted 10 times with methanol. 0.02 mL of 20% phosphoric acid aqueous solution and 0.5 mL of 1000 ppm DNPH acetonitrile solution were added to 1 mL of the diluted solution. The resulting solution was heated for 60 minutes using an aluminum block heater at 60°C. Quantification was performed using a high-performance liquid chromatography (HPLC) system (Waters ACQUITY Ultra Performance LC) under the following conditions. Tube string: ACQUITY UPLC BEH c18 1.7um 2.1×100mm Flow rate: 0.3 mL / min Mobile phase: Acetonitrile / water = 55 / 45 Injection volume: 3μL Column temperature: 40℃ Detector: PDA (360nm) The calibration curve was obtained using a mixed standard stock solution of aldehydes-2,4-DNPH from Kanto Chemical (for HPLC). As a correction for the DNPH reaction rate, the formaldehyde standard solution was diluted to 0.1 ppm and measured in the sample pretreated according to the above procedure.

[0156] (3) Lightfastness test 15g of the composition was placed in a spiral flask and irradiated with a UV lamp (As-One Handy UVLamp SLUV-6) for 4 hours. The formaldehyde content in the solution was then analyzed according to the above procedure. At this time, the UV wavelength was 365nm and the UV intensity was 0.4mW / cm².

[0157] (Refer to Example 1: Modulation of titanium dioxide-tin dioxide composite oxide colloidal particles (A1) that become nuclei) 319.5 g of a 25% (w / w) tetramethylammonium hydroxide aqueous solution was dissolved in 947.1 g of pure water. Then, under stirring, 14.8 g of metastannic acid (containing 12.5 g of SnO₂), 236.6 g of tetraisopropyl titanium oxide (containing 66.6 g of TiO₂), and 82.0 g of oxalic acid dihydrate (containing 58.5 g of oxalic acid) were added. The mixture was kept at 80°C for 2 hours, then further reduced to 580 Torr and kept for 2 hours to prepare the final solution. This final solution was then placed in a glass-lined autoclave and subjected to hydrothermal treatment at 140°C for 5 hours. After cooling to room temperature, the autoclave was removed. The resulting sol was an acidic aqueous dispersion of titanium dioxide-tin dioxide composite oxide colloidal particles (Al), with a pH of 3.9, a total metal oxide concentration (TiO₂ and SnO₂) of 5.0% by mass, and an average particle size of 16 nm as determined by dynamic light scattering. X-ray diffraction analysis of the powder obtained from the sol, dried at 110 °C, confirmed that it was a rutile crystal.

[0158] (Refer to Example 2: Modulation of silicon dioxide-tin dioxide composite oxide colloidal particles (B1) as a coating) 77.2 g of JIS No. 3 sodium silicate (containing 29.8% by mass as SiO₂) was dissolved in 668.8 g of pure water, followed by the dissolution of 20.9 g of sodium stannate (NaSnO₃·H₂O) (containing 55.1% by mass as SnO₂). The resulting aqueous solution was passed through a column packed with hydrogen-form cation exchange resin (Amberlite IR-120B). Then, 7.2 g of diisopropylamine was added to the resulting aqueous dispersion. The resulting sol was an alkaline aqueous dispersion of silicon dioxide-tin dioxide composite oxide colloidal particles (B1), with a pH of 8.0 and a total metal oxide concentration (SiO₂ and SnO₂) of 1.7% by mass. Observations under a transmission electron microscope showed a single particle size of 1–4 nm.

[0159] (Manufacturing Example 1: Modulation of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified by silicon dioxide-tin dioxide composite oxide) 82.7 g of zirconium dichloride (containing 21.2% by mass, converted from ZrO₂) was diluted with 501.1 g of pure water to prepare 583.8 g of zirconium dichloride aqueous solution (containing 3.0% by mass, converted from ZrO₂). 1516.2 g of an aqueous dispersion of titanium dioxide-tin dioxide composite oxide colloidal particles (A1) prepared in Reference Example 1 was added under stirring. Hydrolysis was then carried out by heating to 95°C to obtain an aqueous dispersion of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles with a zirconium oxide film layer formed on the surface. 2041.2 g of the obtained aqueous dispersion was added under stirring to 1763.3 g of an alkaline silicon dioxide-tin dioxide composite oxide colloidal particle (B1) aqueous dispersion prepared in Reference Example 2. The mixture was passed through a 500 mL column packed with anion exchange resin (Amberlite IRA-410, manufactured by ORGANO). Next, the aqueous dispersion sol after liquid permeation was heated at 95°C for 3 hours and then concentrated by ultrafiltration membrane method to obtain an aqueous dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (Cl) modified by silicon dioxide-tin dioxide composite oxide. This aqueous dispersion sol has a pH of 5.2, a total metal oxide (TiO2, ZrO2, SnO2 and SiO2) concentration of 30.5% by mass, a viscosity of 5.0 mPa·s, and an average particle size (dynamic light scattering particle size) of 20 nm as determined by dynamic light scattering method (DLS).

[0160] (Refer to Example 3: Modulation of Zirconia-Tin Dioxide Composite Oxide Colloidal Particles (A2) that become nuclei) 293.7 g of a tetramethylammonium bicarbonate aqueous solution (containing 42.4% by mass as tetramethylammonium hydroxide) was diluted with 111.5 g of pure water. While stirring the aqueous solution, 168.4 g of zirconium oxycarbonate powder (containing 40.1% by mass as ZrO₂) was slowly added. After the addition was complete, the temperature was raised to 85°C, and 9.6 g of metastannic acid (containing 86.0% by mass as SnO₂) was slowly added. The mixture was then aged at 105°C for 5 hours, followed by hydrothermal treatment at 145°C for 5 hours. Next, the sol was washed and concentrated using an ultrafiltration device while adding pure water. The resulting sol was an alkaline aqueous dispersion of zirconium oxide-tin dioxide composite oxide colloidal particles (A₂), with a pH of 9.4, a total metal oxide concentration (combined ZrO₂ and SnO₂) of 5.0% by mass, and an average particle size of 15 nm as determined by dynamic light scattering (Dynamic Light Scattering Particle Size).

[0161] (Manufacturing Example 2: Modulation of Zirconia-Tin Dioxide Composite Oxide Colloidal Particles (C2) Modified by Silicon Dioxide-Tin Dioxide Composite Oxide) To 1411.7 g of the alkaline zirconium oxide-tin dioxide composite oxide colloidal particles (A2) obtained in Reference Example 3, 830.4 g of the alkaline silicon dioxide-tin dioxide composite oxide colloidal particles (B1) prepared in Reference Example 2 were added under stirring. Next, the mixture was heated to 95°C and held for 2 hours. After passing the mixture through a column packed with hydrogen-form cation exchange resin (Amberlite IR-120B), the sol was concentrated using ultrafiltration to obtain an aqueous dispersion of zirconium oxide-tin dioxide composite oxide colloidal particles (C2) modified with silicon dioxide-tin dioxide composite oxide. This aqueous dispersion had a pH of 5.0, a total metal oxide (ZrO2, SnO2, and SiO2) concentration of 30% by mass, a viscosity of 5.3 mPa·s, and an average particle size (DLS particle size) of 20 nm.

[0162] (Refer to Example 4: Modulation of tin dioxide colloidal particles (A3) that become nuclei) 64.0 g of oxalic acid dihydrate (equivalent to 45.7 g of oxalic acid) was dissolved in 723.3 g of pure water. While stirring, the solution was heated to 70°C. Then, 290.3 g of 35% hydrogen peroxide solution and 128.1 g of metallic tin powder (containing 99.7% SnO₂) were added. The hydrogen peroxide solution and metallic tin were added alternately in 10 portions. Initially, 29.0 g of 35% hydrogen peroxide solution was added, followed by 12.8 g of metallic tin. After the reaction was complete (10-15 minutes), this process was repeated. The total addition time was 2 hours. After the addition was complete, the solution temperature was maintained at 90°C while heating for 2 hours to stop the reaction. Next, 394.5 g of 35% hydrogen peroxide solution was added, and the solution was maintained at 90°C for 5 hours. Next, 5.1 g of isopropylamine was added, and after maintaining the temperature at 50°C for 3 hours, the mixture was passed through a 500 mL column packed with anion exchange resin (Amberlite IRA-410). The resulting sol was an aqueous dispersion of alkaline tin dioxide composite oxide colloidal particles (A3), with a pH of 11.0, a SnO2 concentration of 4.0% by mass, and an average particle size of 20 nm as determined by dynamic light scattering (Dynamic Light Scattering Particle Size).

[0163] (Manufacturing Example 3: Modification of Tin Dioxide Colloidal Particles (C3) Modified by Silicon Dioxide-Tin Dioxide Composite Oxide) To 1458.8 g of the aqueous dispersion of tin dioxide colloidal particles (A3) obtained in Reference Example 4, 514.9 g of the alkaline aqueous dispersion of silicon dioxide-tin dioxide composite oxide colloidal particles (B1) prepared in Reference Example 2 was added under stirring. The mixture was then heated to 95°C and held for 2 hours, followed by passing through a column packed with hydrogen-form cation exchange resin (Amberlite IR-120B). The sol was then concentrated using ultrafiltration to obtain an aqueous dispersion of tin dioxide colloidal particles (C3) modified with silicon dioxide-tin dioxide composite oxide. This aqueous dispersion had a total metal oxide (SnO2 and SiO2) concentration of 30.5% by mass, a viscosity of 4.8 mPa·s, and an average particle size (DLS particle size) of 18 nm.

[0164] (Refer to Example 5: Modulation of titanium dioxide colloidal particles (A4) that become nuclei) 1431.0 g of pure water was placed in a 5-liter container. While stirring, 315.0 g of a 35% (w / w) tetraethylammonium hydroxide aqueous solution, 39.6 g of glycine, and 213.2 g of tetraisopropyl titanium oxide (containing 59.9 g of TiO₂) were added. The resulting mixed solution had a molar ratio of tetraethylammonium hydroxide to titanium atoms of 1.00 and a molar ratio of glycine to titanium atoms of 0.70. This mixed solution was kept at 90°C for 2 hours and then at 95°C for 5 hours to prepare a titanium mixed solution. The prepared titanium mixed solution had a pH of 11.1 and a TiO₂ concentration of 3.0% (w / w). 1500 g of the above titanium mixed solution was added to a 3-liter SUS autoclave and subjected to hydrothermal treatment at 150°C for 5 hours. After cooling to room temperature, the hydrothermally treated solution was a milky white aqueous dispersion of titanium oxide colloidal particles. The resulting dispersion had a pH of 12.2, a TiO2 concentration of 3.0% by mass, and an average particle size of 140 nm as determined by dynamic light scattering (DLS).

[0165] (Manufacturing Example 4: Modification of titanium dioxide colloidal particles (C4) modified by silicon dioxide-tin dioxide composite oxide) To 1400.0 g of the aqueous dispersion of titanium dioxide colloidal particles (A4) obtained in Reference Example 5, 247.1 g of the alkaline aqueous dispersion of silicon dioxide-tin dioxide composite oxide colloidal particles (B1) prepared in Reference Example 2 was added under stirring. The mixture was then heated to 95°C and held for 2 hours, followed by passing through a column packed with hydrogen-form cation exchange resin (Amberlite IR-120B). The sol was then concentrated using ultrafiltration to obtain an aqueous dispersion of titanium dioxide colloidal particles (C4) modified with silicon dioxide-tin dioxide composite oxide. This aqueous dispersion had a total metal oxide (TiO2, SnO2, and SiO2) concentration of 30.5% by mass, a viscosity of 3.5 mPa·s, and an average particle size (DLS particle size) of 128 nm.

[0166] (Example 1) In 100g of the aqueous dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Manufacturing Example 1, 69.5g of IPA (isopropanol) and 1.52g of polyoxyethylene alkyl ether phosphate (manufactured by Toho Chemical Industry Co., Ltd.: trade name RA-600) were added under stirring to modify the surface of the particles. Next, the dispersion medium of the resulting aqueous dispersion sol was replaced with IPA using a rotary evaporator to obtain an IPA dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide. This stage reduced the amount of residual methanol in the solvent. The IPA dispersion had a pH of 5.0, a total metal oxide (TiO₂, ZrO₂, SnO₂, and SiO₂) concentration of 20.5% by mass, a viscosity of 2.3 mPa·s, and an average particle size of 22 nm as determined by dynamic light scattering (DLS). The metal oxide particles contained 11.4 mol% SnO₂, 54.8 mol% TiO₂, 10.1 mol% ZrO₂, and 23.6 mol% SiO₂. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 11 ppm. The formaldehyde content before and after the lightfastness test is less than 1 ppm.

[0167] (Example 2) Except that the solvent was changed to propylene glycol monomethyl ether (PGME) in Example 1, the sol was prepared in the same manner as in Example 1. The PGME dispersion sol had a pH of 4.2, a total metal oxide (TiO₂, ZrO₂, SnO₂, and SiO₂) concentration of 30.5% by mass, a viscosity of 4.5 mPa·s, and an average particle size (DLS particle size) of 26 nm. The metal oxide particles contained 11.4 mol% SnO₂, 54.8 mol% TiO₂, 10.1 mol% ZrO₂, and 23.6 mol% SiO₂. At this point, the methanol in the composition is the methanol in the dispersion medium, the residual methanol content is 10 ppm, and the formaldehyde content before and after the lightfastness test is less than 1 ppm.

[0168] (Example 3) In 100g of the aqueous dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Manufacturing Example 1, 30.5g of 5% citric acid aqueous solution was added under stirring. Next, the sol was heated at 90°C for 2 hours to modify the surface of the particles with citric acid. The dispersion medium of the obtained aqueous dispersion sol was replaced with n-propanol using a rotary evaporator to obtain a n-propanol dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide. This stage reduced the amount of methanol remaining in the solvent. The n-propanol dispersion sol had a pH of 3.5, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 19.5% by mass, a viscosity of 2.2 mPa·s, and an average particle size (DLS particle size) of 18 nm. The SnO2 content in the metal oxide particles is 11.4 mol%, TiO2 is 54.8 mol%, ZrO2 is 10.1 mol%, and SiO2 is 23.6 mol%. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 5 ppm. The formaldehyde content before and after the lightfastness test is less than 1 ppm.

[0169] (Example 4) Except that the sol was changed to the zirconium oxide-tin dioxide composite oxide colloidal particles (C2) modified with silicon dioxide-tin dioxide composite oxide as in Example 1, the process was carried out in the same manner as in Example 1. The resulting IPA dispersion sol had a pH of 5.0, a total metal oxide (ZrO2, SnO2, and SiO2) concentration of 20.3% by mass, a viscosity of 2.2 mPa·s, and an average particle size (dynamic light scattering particle size) of 27 nm as determined by dynamic light scattering (DLS). The SnO2 content in the metal oxide particles was 11.8 mol%, the ZrO2 content was 67.2 mol%, and the SiO2 content was 20.9 mol. At this point, the methanol in the composition is the methanol in the dispersion medium, the residual methanol content is 10 ppm, and the formaldehyde content before and after the lightfastness test is less than 1 ppm.

[0170] (Example 5) Except that the sol was changed to tin dioxide colloidal particles (C3) modified with silicon dioxide-tin dioxide composite oxide as in Example 1, the process was carried out in the same manner as in Example 1. The resulting IPA dispersion sol had a pH of 5.0, a total metal oxide (SnO2 and SiO2) concentration of 20.5% by mass, a viscosity of 2.5 mPa·s, and an average particle size (dynamic light scattering particle size) of 26 nm as determined by dynamic light scattering (DLS). The SnO2 content in the metal oxide particles was 80.7 mol%, and the SiO2 content was 19.3 mol%. At this point, the methanol in the composition is the methanol in the dispersion medium, the residual methanol content is 10 ppm, and the formaldehyde content before and after the lightfastness test is less than 1 ppm.

[0171] (Example 6) In 100g of the aqueous dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Example 1, polyether-modified silane (manufactured by Shin-Etsu Chemical Industry Co., Ltd.: trade name X-12-641, structure: ...) was added under stirring. (CH 3O) 3SiC 3H 6(OC 2H 4)nOCH 3) 1.53 g. Next, the sol was heated at 70°C for 5 hours to modify the surface of the particles. The dispersion medium of the resulting aqueous dispersion sol was replaced with n-propanol using a rotary evaporator to obtain a n-propanol dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (Cl) modified with silicon dioxide-tin dioxide composite oxide. This stage reduced residual methanol in the solvent. The n-propanol dispersion sol had a pH of 6.9, a total metal oxide (TiO 2, ZrO 2, SnO 2, and SiO 2) concentration of 30.5% by mass, a viscosity of 4.6 mPa·s, and an average particle size (DLS particle size) of 15 nm. The SnO2 content in the metal oxide particles is 11.4 mol%, TiO2 is 54.8 mol%, ZrO2 is 10.1 mol%, and SiO2 is 23.6 mol%. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 5 ppm. The formaldehyde content before and after the lightfastness test is less than 1 ppm.

[0172] (Example 7) In the propanol dispersion sol of the titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Example 6, methanol was added as the dispersion medium, with the residual methanol content experimentally set at 25 ppm. The metal oxide particles contained 11.4 mol% SnO2, 54.8 mol% TiO2, 10.1 mol% ZrO2, and 23.6 mol% SiO2. The formaldehyde content before and after the lightfastness test of the n-propanol dispersion sol was less than 1 ppm.

[0173] (Example 8) In the propanol dispersion sol of the titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Example 6, methanol was added as the dispersion medium, with the residual methanol content experimentally set at 50 ppm. The metal oxide particles contained 11.4 mol% SnO2, 54.8 mol% TiO2, 10.1 mol% ZrO2, and 23.6 mol% SiO2. The formaldehyde content before and after the lightfastness test of the n-propanol dispersion sol was less than 1 ppm.

[0174] (Example 9) In the propanol dispersion sol of the titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Example 6, methanol was added as the dispersion medium, with the residual methanol content experimentally set at 75 ppm. The metal oxide particles contained 11.4 mol% SnO2, 54.8 mol% TiO2, 10.1 mol% ZrO2, and 23.6 mol% SiO2. The formaldehyde content before and after the lightfastness test of the n-propanol dispersion sol was less than 1 ppm.

[0175] (Example 10) In the propanol dispersion sol of the titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Example 6, methanol was added as the dispersion medium, with the residual methanol content experimentally set at 100 ppm. The metal oxide particles contained 11.4 mol% SnO2, 54.8 mol% TiO2, 10.1 mol% ZrO2, and 23.6 mol% SiO2. The formaldehyde content before and after the lightfastness test of the n-propanol dispersion sol was less than 1 ppm.

[0176] (Example 11) In 100g of the aqueous dispersion sol of titanium dioxide colloidal particles (C4) modified with silicon dioxide-tin dioxide composite oxide obtained in Manufacturing Example 4, 69.3g of IPA and 1.53g of polyoxyethylene alkyl ether phosphate (Toho Chemical Industry Co., Ltd.: RA-600) were added under stirring to modify the surface of the particles. Next, the dispersion medium of the obtained aqueous dispersion sol was replaced with IPA using a rotary evaporator to obtain an IPA dispersion sol of titanium dioxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide. This IPA dispersion sol had a pH of 2.9, a total metal oxide (TiO2, SnO2, and SiO2) concentration of 20.5% by mass, a viscosity of 9.1 mPa·s, and an average particle size (dynamic light scattering particle size) of 375 nm as determined by dynamic light scattering (DLS). The SnO2 content in the metal oxide particles is 1.6 mol%, the TiO2 content is 90.4 mol%, and the SiO2 content is 8.0 mol%. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 9 ppm. The formaldehyde content before and after the lightfastness test is less than 1 ppm.

[0177] (Comparative Example 1) 100 g of the aqueous dispersion sol of titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide obtained in Example 1 was replaced with methanol using a rotary evaporator to obtain a methanol dispersion sol of the titanium dioxide-tin dioxide-zirconia composite oxide colloidal particles (C1) modified with silicon dioxide-tin dioxide composite oxide. This methanol dispersion sol had a pH of 6.0, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 30.0% by mass, a viscosity of 1.4 mPa·s, and an average particle size (DLS particle size) of 18 nm. The metal oxide particles contained 11.4 mol% SnO2, 54.8 mol% TiO2, 10.1 mol% ZrO2, and 23.6 mol% SiO2. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 70%. The formaldehyde content before the lightfastness test is less than 1 ppm, but the formaldehyde content after the lightfastness test is 25 ppm.

[0178] (Comparative Example 2) Except that the dispersion medium was changed to ethanol in Comparative Example 1, the same procedure was followed as in Comparative Example 1. The SnO2 content in the metal oxide particles was 11.4 mol%, TiO2 content was 54.8 mol%, ZrO2 content was 10.1 mol%, and SiO2 content was 23.6 mol%. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual ethanol content is 70%. The acetaldehyde content before the lightfastness test is 3 ppm, and the acetaldehyde content after the lightfastness test is 25 ppm.

[0179] (Comparative Example 3) Except that polyoxyethylene alkyl ether phosphate (Toho Chemical Industry Co., Ltd.: RA-600) was not added in Example 1, the procedure was carried out in the same manner as in Example 1. In this case, the sol system gelled during solvent displacement and was not dispersed in the IPA.

[0180] (Comparative Example 4) Except for replacing 1.22 g of polyoxyethylene alkyl ether phosphate (Toho Chemical Co., Ltd.: RA-600) with 3-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.: KBM-503) in Example 2, the same procedure was followed as in Example 2. The metal oxide particles contained 11.4 mol% SnO2, 54.8 mol% TiO2, 10.1 mol% ZrO2, and 23.6 mol% SiO2. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 400 ppm. The formaldehyde content before the lightfastness test is less than 1 ppm, and the formaldehyde content after the lightfastness test is 7 ppm.

[0181] (Comparative Example 5) Except that, in Comparative Example 1, the sol was changed to the zirconium oxide-tin oxide composite oxide colloidal particles (C2) modified with silicon dioxide-tin oxide composite oxide as in Manufacturing Example 2, the same procedures were followed as in Comparative Example 1. The SnO2 content in the metal oxide particles was 11.8 mol%, the ZrO2 content was 67.2 mol%, and the SiO2 content was 20.9 mol%. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 70%. The formaldehyde content before the lightfastness test is less than 1 ppm, and the formaldehyde content after the lightfastness test is 2 ppm.

[0182] (Comparative Example 6) Except that, in Comparative Example 1, the sol was changed to tin dioxide colloidal particles (C3) modified with silicon dioxide-tin dioxide composite oxide as in Manufacturing Example 3, the same procedures were followed as in Comparative Example 1. The SnO2 content in the metal oxide particles was 80.7 mol%, and the SiO2 content was 19.3 mol%. At this point, the methanol in the composition is the methanol in the dispersion medium, and the residual methanol content is 70%. The formaldehyde content before the lightfastness test is less than 1 ppm, and the formaldehyde content after the lightfastness test is 12 ppm.

[0183] The sols prepared in Examples 1-10 did not undergo gelation or phase separation, demonstrating excellent stability. Furthermore, the formaldehyde generated due to the photocatalytic activity of the particles was less than 1 ppm regardless of whether ultraviolet radiation was applied, confirming excellent lightfastness. On the other hand, compared with the examples, Comparative Examples 1, 2, 5, and 6 contained more methanol and ethanol in their compositions, resulting in the formation of formaldehyde and acetaldehyde during the lightfastness test. Comparative Example 3, lacking surface modification of particles, exhibited poor dispersibility in IPA. Compared with Example 10, Comparative Example 4 contained more residual methanol in its composition, resulting in the formation of formaldehyde during the lightfastness test. Industrial utilization potential

[0184] A composition that inhibits the formation of aldehyde compounds even through photocatalytic action, and a method for manufacturing the same, wherein the composition comprises photoactive metal oxide particles and can inhibit the formation of harmful volatile aldehyde compounds.

Claims

1. A composition comprising an organic solvent (C) other than photoactive metal oxide particles (A), a dispersant (B), and a volatile aldehyde compound, wherein the composition contains an alcohol having 1 to 2 carbon atoms in a proportion of 200 ppm or less, wherein the photoactive metal oxide particles (A) are at least one photoactive metal oxide selected from the group consisting of titanium oxide, tin oxide, and zirconium oxide, comprising at least 50 mol% of all metal oxides.

2. The composition of claim 1, wherein the aforementioned photoactive metal oxide particles (A) comprise at least one photoactive metal oxide selected from the group consisting of titanium oxide, tin oxide and zirconium oxide, and are metal oxide particles with an average particle size of 5 to 500 nm as determined by dynamic light scattering.

3. As claimed in claim 1 or 2, wherein the aforementioned photoactive metal oxide particle (A) is a metal oxide particle composed of a photoactive metal oxide, a metal oxide particle containing a photoactive metal oxide, or a core-shell type metal oxide particle, wherein the core-shell type metal oxide particle is a core-shell type metal oxide particle whose surface is covered by a coating layer of metal oxide particles with a metal oxide composition or metal oxide content different from that of the core metal oxide, wherein the core metal oxide particle, the coating layer metal oxide particle, or both contain a photoactive metal oxide.

4. The composition of claim 3, wherein the aforementioned photoactive metal oxide particles (A) are core-shell type metal oxide particles whose surface is covered by metal oxide particles containing silicon dioxide, and the total metal oxide contains more than 50 moles of titanium oxide.

5. The composition of claim 3, wherein the metal oxide particles of the core are particles of titanium oxide, zirconium oxide, tin oxide, titanium oxide-tin oxide composite oxide, zirconium oxide-tin oxide composite oxide, titanium oxide-zirconia composite oxide, or titanium oxide-zirconia-tin oxide composite oxide.

6. The composition of claim 3, wherein the metal oxide particles of the coating are at least one type of metal oxide particles or composite metal oxide particles selected from the group consisting of silicon dioxide, tin oxide, antimony oxide, tungsten oxide, aluminum oxide and zirconium oxide.

7. The composition of claim 1 or 2, wherein the dispersant (B) is a silane compound, an organic acid or a salt thereof, a phosphate ester or a surfactant.

8. The composition of claim 7, wherein the aforementioned silane compound is a silane coupling agent, the silane coupling agent being at least one silane compound selected from the group consisting of formulas (1) to (3); (in formula (1), R1 is each alkyl, haloalkyl, alkenyl, aryl, or an organic group having a polyether group, epoxy group, (meth)acrylic acid group, mercapto group, amino group, urea group, or cyano group and bonded to silicon atoms by a Si-C bond, R2 each represents an alkoxy group, aceoxy group, or halogroup, and a represents an integer from 1 to 3, In formulas (2) and (3), R3 and R5 are each an alkyl group with 1 to 3 carbon atoms or an aryl group with 6 to 30 carbon atoms bonded to silicon atoms by Si-C bonds, R4 and R6 represent alkoxy, aceoxy, or halogroups, Y represents alkyl, NH, or oxygen atoms, b is an integer from 1 to 3, c is an integer from 0 to 1, and d is an integer from 1 to 3.

9. The composition of claim 7, wherein the organic acid is at least one organic acid selected from the group consisting of divalent aliphatic carboxylic acids, aliphatic hydroxycarboxylic acids, amino acids and chelating agents, wherein the divalent aliphatic carboxylic acid is selected from the group consisting of oxalic acid, malonic acid and succinic acid, the aliphatic hydroxycarboxylic acid is selected from the group consisting of glycolic acid, lactic acid, malic acid, tartaric acid and citric acid, the amino acid is selected from the group consisting of glycine, alanine, valine, leucine, serine and threonine, and the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid, L-aspartic-N,N-diacetic acid and diethylenetriaminepentaacetic acid.

10. The composition of claim 7, wherein the phosphate ester is at least one phosphate ester selected from the group consisting of formulas (4) to (6); (in formulas (4) to (6), X1, X2 and X3 each represent an alkyl group having 2 to 20 carbon atoms, f, h and j each represent an integer from 1 to 100, e, g and i each represent an integer from 1 to 3, and Y1, Y2 and Y3 each represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or a (meth)acrylate group).

11. The composition of claim 7, wherein the phosphate ester is a polyoxyethylene alkyl (C6-10) ether phosphate ester having an alkyl group having 6 to 10 carbon atoms.

12. The composition of claim 7, wherein the surfactant is an anionic surfactant, a cationic surfactant, a nonionic surfactant or an amphoteric surfactant.

13. The composition of claim 1 or 2, wherein the organic solvent (C) is an alcohol, ester, ketone, amide or hydrocarbon having 3 to 10 carbon atoms and having an ether bond.

14. The composition of claim 1 or 2 further comprises a secondary or tertiary amine having a total carbon number of 5 to 35.

15. The composition of claim 1 or 2, wherein when 15 g of the composition is irradiated with ultraviolet light of wavelength 365 nm at an intensity of 0.4 mW / cm2 for 4 hours, the amount of volatile aldehyde compounds generated in the composition is less than 2 ppm.

16. The composition of claim 1 or 2 has a solid content of 0.1 to 70% by mass, and the total solid content contains 80 to 99% by mass of photoactive metal oxide particles (A) and 1 to 20% by mass of dispersant (B).

17. A varnish comprising, further comprising, a thermosetting or photosetting resin in any one of claims 1 to 16.

18. The varnish as described in claim 17, wherein the varnish is a hardening agent or a filler.

19. A method for manufacturing a composition according to any one of claims 1 to 16, comprising the following steps (i) and (ii): Step (i): mixing photoactive metal oxide particles (A), a dispersant (B), and an organic solvent (C) other than a volatile aldehyde compound; Step (ii): removing the liquid obtained in step (i) until the proportion of alcohol having 1 to 2 carbon atoms in the total solvent is less than 200 ppm.