Metal oxide particles having a core-shell structure with a uniform particle size distribution and method for producing the same

Abstract

The present invention provides core-shell type metal oxide particles that are suitable for use in optical thin films such as hard coats, UV-cutting layers, anti-reflective coatings, and diffractive optical element materials, and that have excellent light resistance, transparency, and processability such as imprinting, as well as a high refractive index, and a method for producing the same. [Solution] A core-shell type metal oxide particle (C) is formed by coating the surface of a core metal oxide particle (A1) with a metal oxide (A2) containing titanium oxide, and further coating the coating layer with a metal oxide (A3) whose main component is a metal oxide other than titanium oxide, with an average primary particle diameter of 10 to 20 nm, and the metal oxide particle (A1) is a rutile-type titanium oxide containing at least one selected from the group consisting of tin oxide, zirconium oxide, zinc oxide, iron oxide, nickel oxide, and aluminum oxide.

Description

[Technical Field]

[0001] The present invention relates to core-shell type metal oxide particles having an average primary particle diameter of 10 to 20 nm, wherein the surface of a core metal oxide particle is coated with a metal oxide containing titanium oxide, and this coating is further coated with a metal oxide whose main component is a metal oxide other than titanium oxide, and to a method for producing the same. More specifically, the present invention relates to core-shell type metal oxide particles that are suitably used in optical thin films such as hard coats, ultraviolet cut layers, anti-reflective films, and diffractive optical element materials, and that have excellent light resistance, transparency, and processability such as imprinting, as well as a high refractive index, and to a method for producing the same. [Background technology]

[0002] Conventionally, varnishes containing metal oxide particles have been used to form optical thin films for eyeglass lenses and various displays. For example, since eyeglass lenses can be made thinner the higher the refractive index of the lens substrate, it is preferable for the varnish used for hard coatings of eyeglass lenses to have a high refractive index. Also, while anti-reflective films are generally made by alternately laminating high-refractive-index and low-refractive-index layers, it is preferable for the varnish used in the high-refractive-index layer to have a higher refractive index from the viewpoint of anti-reflective performance. For this reason, it is preferable for the refractive index of the metal oxide particles contained in the varnish to be as high as possible. For example, metal oxides such as titanium dioxide, tantalum oxide, zirconium oxide, and tin oxide are known to have high refractive indices, but among them, titanium dioxide with a rutile-type crystal structure has the highest refractive index and is chemically stable, making it a preferred high-refractive-index metal oxide. Various proposals have been made for such rutile-type titanium dioxide particles (see Patent Documents 1 to 3). Patent Document 1 discloses titanium oxide-containing core-shell type metal oxide particles having one or more intermediate layers between titanium oxide-containing core particles and a coating layer made of silicon dioxide-stannous oxide composite metal oxide covering them, the intermediate layer being made of an oxide, composite metal oxide, or mixture of said oxide and said composite metal oxide of at least one element selected from the group consisting of Si, Al, Sn, Zr, Zn, Sb, Nb, Ta, and W. Patent Document 2 discloses rutile-type core-shell metal oxide particles in which core particles made of one of tin oxide, zinc-added titanium oxide, or tin-added titanium oxide are coated with rutile-type titanium oxide. Patent Document 3 discloses rutile-type titanium oxide particles containing 90% by weight or more of titanium oxide in terms of TiO2. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 5896178 [Patent Document 2] Japanese Patent Publication No. 2008-308386 [Patent Document 3] International Publication No. 2022 / 210973 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, according to the inventors' findings, the titanium oxide-containing core-shell type metal oxide particles described in Patent Document 1 may have a low refractive index as core-shell type metal oxide particles because the intermediate layer uses a material with a lower refractive index than titanium oxide. Furthermore, the rutile-type core-shell metal oxide particles described in Patent Document 2 may have insufficient light resistance because the outermost layer is titanium oxide, and optical activity cannot be suppressed. Moreover, the rutile-type titanium oxide particles described in Patent Document 3 may have insufficient transparency due to the large dispersion particle size and insufficient light resistance due to the large amount of titanium oxide in the particles. Therefore, the present invention aims to provide core-shell type metal oxide particles that are suitably used in optical thin films such as hard coats, ultraviolet cut layers, anti-reflective films, and diffractive optical elements, and that have excellent light resistance, transparency, and processability such as imprinting, as well as a high refractive index, and a method for producing the same, wherein the surface of a core metal oxide particle is coated with a metal oxide containing titanium oxide, and the coating is further coated with a metal oxide whose main component is a metal oxide other than titanium oxide, and the core-shell type metal oxide particles have an average primary particle diameter of 10 to 20 nm, and a method for producing the same. [Means for solving the problem]

[0005] The present invention, in first view, is a core-shell type metal oxide particle (C) having an average primary particle diameter of 10 to 20 nm, and a standard deviation σ of the circular equivalent particle diameter of the particle when the metal oxide particle is observed with a transmission electron microscope being less than 3 nm. From a second perspective, the core-shell type metal oxide particle (C) is a core-shell type metal oxide particle (C) in which the surface of a core metal oxide particle (A1) is coated with a metal oxide (A2) containing titanium oxide, and the coating is further coated with a metal oxide (A3) whose main component is a metal oxide other than titanium oxide, wherein the metal oxide particle (A1) is a rutile-type titanium oxide containing at least one selected from the group consisting of tin oxide, zirconium oxide, zinc oxide, iron oxide, nickel oxide, and aluminum oxide, as described in the first perspective. As a third viewpoint, the core-shell type metal oxide particle (C) according to the first or second viewpoint comprises at least one metal oxide selected from the group consisting of zirconium oxide, tin oxide, silicon dioxide, zinc oxide, antimony oxide, niobium oxide, tungsten oxide, aluminum oxide, and tantalum oxide, or two or more composite oxides. As a fourth viewpoint, the core-shell type metal oxide particle (C) described in any one of the first to third viewpoints, wherein the metal oxide (A3) is a composite metal oxide of tin oxide and silicon dioxide. As a fifth viewpoint, the core-shell type metal oxide particle (C) described in any one of the first to fourth viewpoints, wherein the refractive index of the core-shell type metal oxide particle (C) is 2.1 to 2.7. As the sixth point, core-shell type metal oxide particles (C) described in any one of the first to fifth points, containing 60 to 85% by mass of titanium oxide in terms of TiO2 equivalent, As a seventh viewpoint, the core-shell type metal oxide particles (C) described in any one of the first to sixth viewpoints are further coated with a coating (B), As the eighth aspect, the core-shell type metal oxide particle (C) according to any one of the first to seventh aspects, wherein the coating (B) is at least one selected from the group consisting of amines (B1), silane compounds (B2), organic acids and organic acid esters (B3), phosphate esters (B4), or surfactants (B5). The ninth aspect is the core-shell type metal oxide particle (C) according to the eighth aspect, wherein the amine (B1) is a secondary amine and / or tertiary amine having a total number of carbon atoms of 5 to 35. As a tenth aspect, the silane compound (B2) is represented by the following formulas (1) to (3):

[0006] [Chemical formula]

[0007] (In formula (1), each of R 1 is an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having a polyether group, an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, or a cyano group and is bonded to a silicon atom by a Si-C bond, and each of R 2 represents an alkoxy group, an acyloxy group, or a halogen group, a represents an integer of 1 to 3, In formulas (2) and (3), each of R 3 and R 5 is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms and is bonded to a silicon atom by a Si-C bond, each of R 4 and R 6 represents an alkoxy group, an acyloxy group, or a halogen group, Y represents an alkylene group, an NH group, or an oxygen atom, b is an integer of 1 to 3, c is an integer of 0 or 1, and d is an integer of 1 to 3.) The core-shell type metal oxide particles (C) according to the eighth aspect, which are at least one hydrolyzate and / or dehydrated condensate of a silane compound selected from the group consisting of As an eleventh aspect, the organic acid and the organic acid ester (B3) are acetic acid, benzoic acid, oxalic acid, malonic acid, succinic acid, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, or an alkyl, aryl, or arylalkyl ester thereof, and the core-shell type metal oxide particles (C) according to the eighth aspect As a twelfth aspect, the phosphate ester (B4) is represented by the following formulas (4) to (6):

[0008] [Chemical formula]

[0009] (In formulas (4) to (6), X1, X2, and X3 each represent an alkylene 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, an aryl group having 6 to 30 carbon atoms, or a (meth)acrylic group.) The core-shell type metal oxide particle (C) according to the eighth aspect, is at least one phosphate ester selected from the group consisting of (4) to (6), As a 13th viewpoint, the core-shell type metal oxide particle (C) according to the 8th viewpoint is an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant. As the 14th viewpoint, a core-shell type metal oxide sol comprising core-shell type metal oxide particles (C) and a dispersion medium as described in any one of the 1st to 13th viewpoints, From the 15th perspective, the core-shell type metal oxide sol according to the 14th perspective, wherein the dispersion medium is water, alcohol, ether, ester, ketone, amide, hydrocarbon, or a combination thereof. As the 16th aspect, a varnish comprising core-shell type metal oxide particles (C) or core-shell type metal oxide sol described in any one of the 1st to 15th aspects, and a thermosetting and / or photocurable resin, As a 17th viewpoint, the varnish described in the 16th viewpoint is a varnish for improving lightfastness. As the 18th point, the varnish described in the 16th point is a varnish for hard courts. The varnish according to the 16th view, wherein the varnish is a varnish for nanoimprinting. As the 20th point of view, the following steps (i), (ii), and (iii): (i) Step: Add a precursor raw material of a metal oxide (A2) containing titanium dioxide to a metal oxide sol in which water containing core metal oxide particles (A1) is used as a dispersion medium. (ii) Step: A sol containing the core metal oxide particles (A1) and the precursor raw material of the titanium oxide-containing metal oxide (A2) obtained in step (i) is heated to coat the surface of the core metal oxide particles (A1) with the titanium oxide-containing metal oxide (A2). (iii) Step: Add a sol containing a metal oxide (A3) whose main component is a metal oxide other than titanium dioxide, with water as the dispersion medium, to the sol obtained in step (ii), and then heat it further in step (iii). This is a method for producing a core-shell type metal oxide sol according to the 14th or 15th aspect, which includes the above. [Effects of the Invention]

[0010] According to the present invention, core-shell type metal oxide particles that are suitably used in optical thin films such as hard coats, ultraviolet cut layers, anti-reflective films, and diffractive optical elements, and that have excellent light resistance, transparency, and processability such as imprinting, as well as a high refractive index, and a method for producing the same, are provided, wherein the surface of rutile-type titanium oxide particles, which form a core and contain at least one selected from the group consisting of tin oxide, zirconium oxide, zinc oxide, iron oxide, nickel oxide, and aluminum oxide, is coated with a metal oxide containing titanium oxide, and the coating is further coated with a metal oxide whose main component is a metal oxide other than titanium oxide, and the average primary particle diameter is 10 to 20 nm, and a method for producing the same can be provided. Because titanium dioxide particles have high photoactivity, when mixed with various binders and resin components used in high refractive index materials as matrix components, they may cause discoloration or degradation of the matrix components.

[0011] To suppress the photoactivity of titanium dioxide particles, core-shell type titanium dioxide particles can be formed by coating rutile-type metal oxide particles containing titanium dioxide with a metal oxide other than titanium dioxide. In core-shell type titanium dioxide particles, when the core rutile-type metal oxide particles containing titanium dioxide are coated with a metal oxide other than titanium dioxide that forms the shell, the lower the proportion of the metal oxide component other than titanium dioxide that forms the shell relative to the core particles, the higher the refractive index of the core-shell type titanium dioxide particles can be obtained. When the average primary particle diameter of core-shell type titanium dioxide particles is less than 10 nm, the specific surface area of ​​the particles is large. Therefore, when mixed with matrix components such as various binders and resin components, the contact area between the core-shell type titanium dioxide particles and the matrix components becomes large, which may cause discoloration or degradation of the matrix components due to the photoactivity of titanium dioxide.

[0012] In contrast, by setting the average primary particle diameter of core-shell type titanium dioxide particles to 10-20 nm, when mixed with matrix components such as various binders and resin components, the contact area between the core-shell type titanium dioxide particles and the matrix components can be reduced, thereby suppressing discoloration and degradation of the matrix components due to the photoactivity of titanium dioxide. In core-shell type titanium oxide particles with an average primary particle diameter of 10-20 nm, if there are many coarse particles with a primary particle diameter greater than 20 nm, the varnish obtained by mixing the particles and matrix components may not provide sufficient film transparency due to light scattering. In contrast, by coating the surface of the core rutile-type titanium oxide particles with titanium oxide buildup, the number of coarse particles greater than 20 nm can be reduced, thereby achieving sufficient film transparency. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described below. However, the embodiments described below are illustrative for explaining the present invention, and the present invention is not limited in any way to the embodiments described below. One embodiment of the present invention is a core-shell type metal oxide particle (C) in which the surface of a core metal oxide particle (A1) is coated with a metal oxide (A2) containing titanium oxide, and the coating is further coated with a metal oxide (A3) whose main component is a metal oxide other than titanium oxide, the average primary particle diameter being 10 to 20 nm, and the metal oxide particle (A1) is a rutile-type titanium oxide containing at least one selected from the group consisting of tin oxide, zirconium oxide, zinc oxide, iron oxide, nickel oxide, and aluminum oxide.

[0014] The core metal oxide particles (A1) are preferably rutile-type titanium oxide containing tin oxide. Examples include composite metal oxide particles of titanium oxide and tin oxide, composite metal oxide particles of titanium oxide, tin oxide and zirconium oxide, composite metal oxide particles of titanium oxide, tin oxide and zinc oxide, composite metal oxide particles of titanium oxide, tin oxide and iron oxide, composite metal oxide particles of titanium oxide, tin oxide and nickel oxide, and composite metal oxide particles of titanium oxide, tin oxide and aluminum oxide. These can be made to have an average particle size of 5-15 nm and 7-13 nm by transmission electron microscopy observation.

[0015] The titanium oxide-containing metal oxide (A2) coating the core is preferably mainly composed of titanium oxide, and may contain 50% by mass or more, 50-100% by mass, 60-100% by mass, 70-100% by mass, 80-100% by mass, 90-100% by mass, or 95-100% by mass.

[0016] The metal oxide (A3) coating the core metal oxide particles (A1) coated with a titanium oxide-containing metal oxide (A2) can be a metal oxide in which zirconium oxide, tin oxide, silicon dioxide, zinc oxide, antimony oxide, niobium oxide, tungsten oxide, aluminum oxide, or tantalum oxide exists individually, or a composite metal oxide formed by combining multiple of the above metal oxides. Examples of composite metal oxides include a composite metal oxide of tin oxide and silicon dioxide, a composite metal oxide of tin oxide, zirconium oxide, and silicon dioxide, a composite metal oxide of tin oxide, tungsten oxide, and silicon dioxide, and a composite metal oxide of antimony oxide and silicon dioxide. When the metal oxide used for coating contains silicon dioxide, the ratio of silicon dioxide to other metal oxides can be 0.1-5.0, 0.5-5.0, 1.0-5.0, 0.1-4.0, or 0.5-4.0 in mass ratio of (silicon dioxide) / (other metal oxides).

[0017] For example, core-shell type metal oxide particles (C) include combinations of (A1) / (A2) / (A3) such as: composite metal oxide particles of titanium oxide and tin oxide / titanium oxide / composite metal oxide of tin oxide and silicon dioxide; composite metal oxide particles of titanium oxide, tin oxide and zirconium oxide / titanium oxide / composite metal oxide of tin oxide and silicon dioxide; composite metal oxide particles of titanium oxide, tin oxide and zinc oxide / titanium oxide / composite metal oxide of tin oxide and silicon dioxide; composite metal oxide particles of titanium oxide, tin oxide and iron oxide / composite metal oxide of titanium oxide / composite metal oxide of tin oxide and silicon dioxide; composite metal oxide particles of titanium oxide, tin oxide and nickel oxide / composite metal oxide of titanium oxide, tin oxide and silicon dioxide; and composite metal oxide particles of titanium oxide, tin oxide and aluminum oxide / composite metal oxide of titanium oxide, tin oxide and silicon dioxide. These core-shell type metal oxide particles (C) have an average primary particle diameter of 10-20 nm, 10-18 nm, or 12-18 nm, as observed with a transmission electron microscope. By setting the average primary particle diameter to 10-20 nm as observed with a transmission electron microscope, it is possible to achieve both a high refractive index and high light resistance.

[0018] The core-shell type metal oxide particles (C) described above were observed with a transmission electron microscope, and the standard deviation σ of the equivalent circle particle size of 500 randomly selected particles was less than 3 nm, for example, 0.1-3 nm, 0.3-3 nm, 0.5-3 nm, or 1.0-3 nm. By making the standard deviation σ of the equivalent circle particle size of the particles less than 3 nm, the content of coarse and fine particles is reduced, and the transparency and processability such as imprinting can be improved when a varnish containing these particles is produced. The refractive index of the above-mentioned core-shell type metal oxide particles (C) is 2.1 or higher, and for example, core-shell type metal oxide particles in the range of 2.1 to 2.7, 2.1 to 2.5, or 2.1 to 2.4 can be obtained.

[0019] The above core-shell type metal oxide particles (C) contain 60-85% by mass, 65-85% by mass, or 65-80% by mass of titanium oxide in terms of TiO2.

[0020] As an example of coating core metal oxide particles (A1) with a titanium oxide-containing metal oxide (A2), an aqueous sol of core-shell type metal oxide particles can be obtained in which the core metal oxide particles (A1) are coated with a titanium oxide-containing metal oxide (A2) by mixing a titania source (D) that generates titanium oxide by hydrolysis and dehydration condensation reaction with an aqueous sol containing rutile-type titanium oxide particles made of a composite metal oxide of titanium oxide and tin oxide having an average primary particle size of 5 to 15 nm. Examples of such titania sources (D) include titanium tetra-i-propoxide, titanium tetra-n-butoxide, titanium tetra-t-butoxide, titanium tetrachloride, and titanyl sulfate, and it is preferable that no titania particles are generated before mixing with the core metal oxide particles (A1).

[0021] The solid content concentration of the aqueous sol of the core metal oxide particles (A1) is 0.5 to 50% by mass, and preferably 5 to 30% by mass.

[0022] The aqueous sol of the core metal oxide particles (A1) can have a pH of 5 to 11.5, preferably 7 to 11.5. The pH of the aqueous sol can be adjusted as needed with an alkaline component. Examples of alkaline components that can be used 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.

[0023] When a core metal oxide particle (A1) is coated with a metal oxide (A2) containing titanium dioxide, and then further coated with a metal oxide (A3) whose main component is a metal oxide other than titanium dioxide, taking a composite metal oxide of tin oxide and silicon dioxide used for coating as an example, sodium stannate or potassium stannate can be used as the alkali stannate, with sodium stannate being preferred. Sodium silicate or potassium silicate can be used as the alkali silicate.

[0024] Alkaline stannate and alkali silicate are prepared as aqueous solutions containing silicon dioxide / stannous oxide in a mass ratio of 0.1 to 5, and then the cations present in the aqueous solution can be removed using a cation exchange resin.

[0025] Alkaline stanate and alkali silicate are prepared by weighing them so that the mass ratio of silicon dioxide to stannous oxide is 0.1 to 5.0 and dissolving them in water. The preferred solid content concentration of the aqueous solution is 1 to 12% by mass as (SnO2 + SiO2).

[0026] The prepared aqueous solution is then decationed using a cation exchange resin. A hydrogen-type strongly acidic cation exchange resin is preferred as the cation exchange resin; for example, Amberlite (trade name) 120B can be packed into the column and used. Through this cation exchange, the silicate component and the stannic acid component polymerize, yielding a composite metal oxide of stannic oxide and silicon dioxide.

[0027] This composite metal oxide of stannic oxide and silicon dioxide has poor stability and gels within a few hours if left standing. Therefore, after cation exchange, it is necessary to quickly add an amine compound to stabilize it, and obtain an aqueous dispersion of the composite metal oxide of stannic oxide and silicon dioxide (A3) stabilized with an amine compound present in a molar ratio of 0.001 to 0.08 M / (SnO2+SiO2) (where M represents the amine compound) with a silicon dioxide / stannic oxide mass ratio of 0.1 to 5.0. If the amount of amine compound added is less than 0.001 in the M / (SnO2+SiO2) molar ratio, the dispersion stability of the composite metal oxide of stannic oxide and silicon dioxide will be insufficient, which is undesirable. Also, if the M / (SnO2+SiO2) molar ratio exceeds 0.08, it may interfere with coating the particle surface of the core-shell type metal oxide particles (C) with a coating material (B). The resulting aqueous dispersion contains 0.1-10% by mass, 0.5-10% by mass, or 0.5-8% by mass of (SnO2 + SiO2).

[0028] Next, an aqueous sol containing core metal oxide particles (A1) having an average primary particle diameter of 5 to 15 nm coated with a titanium oxide-containing metal oxide (A2), and an aqueous dispersion of a composite metal oxide (A3) of stannic oxide and silicon dioxide stabilized with an amine compound having a mass ratio of silicon dioxide to stannic oxide of 0.1 to 5.0 and a molar ratio of 0.001 to 0.08 M / (SnO2+SiO2) (where M represents the amine compound), are used as described above. By mixing (A1) and (A2) in a mass ratio of {(A1)+(A2)} / (A3) of 0.05 to 0.40, an aqueous sol of core-shell type metal oxide particles (C) can be obtained, in which the metal oxide particles (A1) are coated with the titanium oxide-containing metal oxide (A2), and this coating is further coated with the stannic oxide-silicon dioxide-composite metal oxide (A3). If the mass ratio is less than 0.05, the stannic oxide-silicon dioxide-composite metal oxide (A3) cannot sufficiently coat the core metal oxide particles (A1) coated with the titanium oxide-containing metal oxide (A2), and a stable hydrophilic organic solvent dispersion sol or a hydrophobic organic solvent dispersion sol having a water solubility of 0.05 to 12% by mass cannot be obtained. If the mass ratio is greater than 0.40, the particle refractive index becomes too low. It is preferable to mix the aqueous sol containing the core metal oxide particles (A1) coated with a titanium oxide-containing metal oxide (A2) with the aqueous dispersion of the composite metal oxide (A3) under stirring.

[0029] In the present invention, the core-shell type metal oxide particles (C) can be further coated with a secondary or tertiary amine having a total of 5 to 35 carbon atoms. The amine content can be set to 0.1 to 10.0 mmol or 0.5 to 10.0 mmol per 100 g of the core-shell type metal oxide particles (C).

[0030] Examples of the above secondary amines include ethyl n-propylamine, ethyl isopropylamine, dipropylamine, diisopropylamine, ethylbutylamine, n-propylbutylamine, dibutylamine, ethylpentylamine, n-propylpentylamine, isopropylpentylamine, dipentylamine, ethyloctylamine, i-propyloctylamine, butyloctylamine, and dioctylamine.

[0031] Examples of the above-mentioned tertiary amines include triethylamine, ethyldi-n-propylamine, diethyl-n-propylamine, tri-n-propylamine, triisopropylamine, ethyldibutylamine, diethylbutylamine, isopropyldibutylamine, diisopropylethylamine, diisopropylbutylamine, tributylamine, ethyldipentylamine, diethylpentylamine, tripentylamine, methyldioctylamine, dimethyloctylamine, ethyldioctylamine, diethyloctylamine, trioctylamine, benzyldibutylamine, and diazabicycloundecene.

[0032] Among the above amines, secondary and tertiary amines having an alkyl group with a total of 6 to 35 carbon atoms are preferred, such as diisopropylamine, tripentylamine, triisopropylamine, dimethyloctylamine, and trioctylamine.

[0033] In the present invention, the core-shell type metal oxide particles (C) can be further coated with a hydrolysate and / or dehydration condensate of at least one silane compound selected from the group consisting of formulas (1) to (3).

[0034] In formula (1), R 1 Each of these is an organic group having an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or a polyether group, an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, or a cyano group, and is bonded to a silicon atom by a Si-C bond, R2 each represents an alkoxy group, an acyloxy group, or a halogen group, a represents an integer of 1 to 3, In Formula (2) and Formula (3), R 3 and R 5 each is an alkyl group having 1 to 3 carbon atoms, or an aryl group having 6 to 30 carbon atoms and bonded to a silicon atom by a Si-C bond, R 4 and R 6 each represents an alkoxy group, an acyloxy group, or a halogen group, Y represents an alkylene group, an NH group, or an oxygen atom, b is an integer of 1 to 3, c is an integer of 0 or 1, and d is an integer of 1 to 3.

[0035] The alkyl group mentioned above is an alkyl group having 1 to 18 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, cyclopropyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group, and 2,2-dimethyl-n-propyl group. 1-ethyl-n-propyl group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl- n-butyl group, 2,2-dimethyl-n-butyl group, 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2-methyl-cyclopentyl group, 3-methyl-cyclopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclo Butyl group, 3-ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,Examples include, but are not limited to, 3-trimethylcyclopropyl group, 1-ethyl-2-methylcyclopropyl group, 2-ethyl-1-methylcyclopropyl group, 2-ethyl-2-methylcyclopropyl group and 2-ethyl-3-methylcyclopropyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc. Furthermore, examples of alkylene groups include alkylene groups derived from the alkyl groups mentioned above.

[0036] The above-mentioned aryl groups are aryl groups having 6 to 30 carbon atoms, such as phenyl groups, naphthyl groups, anthracene groups, and pyrene groups. Alkenyl groups include alkenyl groups having 2 to 10 carbon atoms, such as ethenyl group, 1-propenyl group, 2-propenyl group, 1-methyl-1-ethenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethylethenyl group, 1-methyl-1-propenyl group, 1-methyl-2-propenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 1-n-propylethenyl group, 1-methyl-1-butenyl group, 1-methyl-2-butenyl group, 1-methyl-3-butenyl group, 2-ethyl-2-propenyl group, 2-methyl-1-butenyl group, 2-methyl-2-butenyl group, 2-methyl-3-butenyl group, and 3 Examples of but not limited to the following are methyl-1-butenyl group, 3-methyl-2-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1-i-propylethenyl group, 1,2-dimethyl-1-propenyl group, 1,2-dimethyl-2-propenyl group, 1-cyclopentenyl group, 2-cyclopentenyl group, 3-cyclopentenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, 1-methyl-1-pentenyl group, 1-methyl-2-pentenyl group, 1-methyl-3-pentenyl group, 1-methyl-4-pentenyl group, 1-n-butylethenyl group, 2-methyl-1-pentenyl group, 2-methyl-2-pentenyl group, etc.

[0037] Examples of the alkoxy groups mentioned above include alkoxy groups having 1 to 10 carbon atoms, such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, n-pentyloxy group, 1-methyl-n-butoxy group, 2-methyl-n-butoxy group, 3-methyl-n-butoxy group, 1,1-dimethyl-n-propoxy group, 1,2-dimethyl-n-propoxy group, 2,2-dimethyl-n-propoxy group, 1-ethyl-n-propoxy group, and n-hexyloxy group, but are not limited to these.

[0038] Examples of the above-mentioned acyloxy groups include, but are not limited to, acyloxy groups having 2 to 10 carbon atoms, such as methyl carbonyloxy group, ethyl carbonyloxy group, n-propyl carbonyloxy group, i-propyl carbonyloxy group, n-butyl carbonyloxy group, i-butyl carbonyloxy group, s-butyl carbonyloxy group, t-butyl carbonyloxy group, n-pentyl carbonyloxy group, 1-methyl-n-butyl carbonyloxy group, 2-methyl-n-butyl carbonyloxy group, 3-methyl-n-butyl carbonyloxy group, 1,1-dimethyl-n-propyl carbonyloxy group, 1,2-dimethyl-n-propyl carbonyloxy group, 2,2-dimethyl-n-propyl carbonyloxy group, 1-ethyl-n-propyl carbonyloxy group, n-hexyl carbonyloxy group, 1-methyl-n-pentyl carbonyloxy group, and 2-methyl-n-pentyl carbonyloxy group. Examples of the halogen groups mentioned above include fluorine, chlorine, bromine, and iodine.

[0039] Examples of organic groups having a polyether group include polyetherpropyl groups having an alkoxy group. For example, (CH3O)3SiC3H6(OC2H4)nOCH3 can be used. n can be used in the range of 1 to 100 or 1 to 10. Examples of organic groups having an epoxy group include the 2-(3,4-epoxycyclohexyl)ethyl group and the 3-glycidoxypropyl group.

[0040] The above-mentioned (meth)acryloyl group refers to both an acryloyl group and a methacryloyl group. Examples of organic groups having a (meth)acryloyl group include 3-methacryloxypropyl group and 3-acryloxypropyl group.

[0041] An example of an organic group having a mercapto group is the 3-mercaptopropyl group. Examples of organic groups having an amino group include 2-aminoethyl group, 3-aminopropyl group, N-2-(aminoethyl)-3-aminopropyl group, N-(1,3-dimethylbutylidene)aminopropyl group, N-phenyl-3-aminopropyl group, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl group.

[0042] An example of an organic group having a ureido group is the 3-ureidopropyl group. An example of an organic group having a cyano group is the 3-cyanopropyl group. Formulas (2) and (3) above are preferably compounds that can form a trimethylsilyl group on the surface of silica particles. Examples of such compounds are listed below.

[0043] [ka]

[0044] In the above formula, R 12 The group is an alkoxy group, such as a methoxy group or an ethoxy group. The silane compound used can be a silane compound manufactured by Shin-Etsu Chemical Co., Ltd. The hydroxyl groups on the surface of the core-shell type metal oxide particles (C) react with the silane compound, thereby coating the core-shell type metal oxide particles (C) with the silane compound (B2). The reaction temperature can be from 20°C to the boiling point of the dispersion medium, but can be, for example, in the range of 20°C to 100°C. The reaction time can be from 0.1 to 6 hours.

[0045] The above silane compound has a coating amount on the surface of the core-shell type metal oxide particles (C) such that the number of silicon atoms in the silane compound is 0.1 atoms / nm. 2 ~6.0 pieces / nm 2 Coating can be performed by adding a silane compound equivalent to the coating amount to the sol containing the core-shell type metal oxide particles (C).

[0046] While water is necessary for the hydrolysis of the above silane compounds, if an aqueous solvent sol is used, then those aqueous solvents can be utilized. When an aqueous medium is replaced with an organic solvent, the water remaining in the solvent can be used. For example, water present at 0.01 to 1% by mass can be used. Furthermore, hydrolysis can be carried out with or without a catalyst.

[0047] Hydrolysis without a catalyst occurs when the surface of core-shell type metal oxide particles (C) is on the acidic side. When hydrolysis is performed with a catalyst, examples of hydrolysis catalysts include metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases. Examples of metal chelate compounds as hydrolysis catalysts include triethoxy mono(acetylacetonate) titanium and triethoxy mono(acetylacetonate) zirconium. Examples of organic acids as hydrolysis catalysts include acetic acid and oxalic acid. Examples of inorganic acids as hydrolysis catalysts include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid. Examples of organic bases as hydrolysis catalysts include pyridine, pyrrole, piperazine, and quaternary ammonium salts. Examples of inorganic bases as hydrolysis catalysts include ammonia, sodium hydroxide, and potassium hydroxide.

[0048] Examples of organic acids include at least one organic acid selected from the group consisting of divalent aliphatic carboxylic acids, aliphatic oxycarboxylic acids, amino acids, and chelating agents. Examples of divalent aliphatic carboxylic acids include oxalic acid, malonic acid, and succinic acid. Examples of aliphatic oxycarboxylic acids include glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid. Examples of amino acids include glycine, alanine, valine, leucine, serine, and trionine. Examples of chelating agents include ethylenediaminetetraacetic acid, L-aspartic acid-N,N-diacetic acid, and diethylenetriaminepentaacetic acid. Examples of organic acid salts include alkali metal salts, ammonium salts, and amine salts of the above organic acids. Examples of alkali metals include sodium and potassium. In the present invention, the core-shell type metal oxide particles (C) can be further coated with at least one organic acid and / or organic acid ester (B3) selected from the group consisting of acetic acid, benzoic acid, oxalic acid, malonic acid, succinic acid, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, or alkyl, aryl, or arylalkyl esters thereof.

[0049] The present invention further includes core-shell type metal oxide particles (C) coated with at least one phosphate ester (B4) selected from the group consisting of formulas (4) to (6). In formulas (4) to (6), X1, X2, and X3 each represent an alkylene 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)acrylic group. Polyoxyethylene alkyl (C6-20) ether phosphate esters having an alkyl group with 6 to 20 carbon atoms can be used.

[0050] Polyoxyethylene alkyl ether phosphate esters can be preferably used as the phosphate esters, but the phosphate esters that can be used are those in which the terminal alkyl group (Y1) of formula (4) has 6 to 10 or 12 to 15 carbon atoms. Examples of such products include Phosphanol RA-600, RS-610, RS-710, and RP-710, manufactured by Toho Chemical Industry Co., Ltd. In the present invention, the core-shell type metal oxide particles (C) can be further coated with at least one surfactant (B5) selected from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants, or amphoteric surfactants.

[0051] Examples of anionic surfactants used in the present invention include sodium and potassium salts of fatty acids, alkylbenzene sulfonates, higher alcohol sulfates, polyoxyethylene alkyl ether sulfates, α-sulfo fatty acid esters, α-olefin sulfonates, monoalkyl phosphates, and alkanesulfonates. For example, alkylbenzene sulfonates include sodium salts, potassium salts, and lithium salts, such as sodium C10-C16 alkylbenzene sulfonate, C10-C16 alkylbenzene sulfonic acid, and sodium alkylnaphthalene sulfonate.

[0052] Examples of higher alcohol sulfate salts include sodium dodecyl sulfate (sodium lauryl sulfate), triethanolamine lauryl sulfate, and triethanolammonium lauryl sulfate, all of which have 12 carbon atoms.

[0053] Polyoxyethylene alkyl ether sulfates include sodium polyoxyethylene styrene-phenyl ether sulfate, ammonium polyoxyethylene styrene-phenyl ether sulfate, sodium polyoxyethylene decyl ether sulfate, ammonium polyoxyethylene decyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, ammonium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene tridecyl ether sulfate, and sodium polyoxyethylene oleyl cetyl ether sulfate.

[0054] Examples of α-olefin sulfonates include sodium α-olefin sulfonate. Examples of alkanesulfonates include sodium 2-ethylhexyl sulfate. Examples of cationic surfactants used in the present invention include alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, and amine salt-based agents.

[0055] Alkyltrimethylammonium salts are quaternary ammonium salts that have chloride ions or bromide ions as counterions. Examples of such quaternary ammonium salts include dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, coconut alkyltrimethylammonium chloride, and alkyl(C16-18)trimethylammonium chloride. Dialkyldimethylammonium salts have two lipophilic main chains and two methyl groups. Examples of such dialkyldimethylammonium salts include bis(hydrogenated tallow)dimethylammonium chloride, didecyldimethylammonium chloride, dialkyldimethylammonium chloride, dihydrogenated tallow alkyldimethylammonium chloride, and dialkyl(C14-18)dimethylammonium chloride.

[0056] Examples of alkyldimethylbenzylammonium salts include quaternary ammonium salts having one lipophilic main chain, two methyl groups, and one benzyl group, such as benzaukonium chloride. For example, alkyl(C8-18)dimethylbenzylammonium chloride is one such example. Examples of amine salt-based agents include those in which ammonia hydrogen atoms are substituted with one or more hydrocarbon groups, such as N-methylbishydroxyethylamine fatty acid ester hydrochloride.

[0057] Examples of amphoteric surfactants used in the present invention include N-alkyl-β-alanine type alkylamino 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-hydroxyethylimidazolinium betaine, and lauryldimethylamine oxide.

[0058] Nonionic surfactants used in the present invention are selected from 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, polyoxyethylene alkyl ethers include polyoxyethylene dodecyl ether (polyoxyethylene lauryl ether), polyoxyalkylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyalkylene tridecyl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, polyoxyethylene-2-ethylhexyl ether, and polyoxyethylene isodecyl ether.

[0059] Examples of polyoxyethylene alkylphenol ethers include polyoxyethylene styrene-modified phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene disstyrene-modified phenyl ether, and polyoxyethylene tripenzylphenyl ether.

[0060] Examples of alkyl glucosides include decyl glucoside and lauryl glucoside.

[0061] Examples of polyoxyethylene fatty acid esters include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol diolate, and polypropylene glycol diolate. 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.

[0062] 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.

[0063] Other examples of fatty acid alkanolamides include coconut oil fatty acid diethanolamide, beef tallow fatty acid diethanolamide, lauric acid diethanolamide, and oleic acid diethanolamide.

[0064] Furthermore, examples include polyoxyethylene polyoxypropylene glycol, polyoxyethylene fatty acid esters, polyoxyalkyl ethers or polyoxyalkyl glycols, polyoxyethylene hydrogenated castor oil ether, sorbitan fatty acid ester alkyl ether, alkyl polyglucoside, sorbitan monooleate, and sucrose fatty acid ester.

[0065] In this invention, a core-shell type metal oxide sol having an average primary particle size of 10 to 20 nm is obtained by dispersing core-shell type metal oxide particles (C) as a dispersed phase in a dispersion medium consisting of water, alcohol, ether, ester, ketone, amide, hydrocarbon, or a combination thereof.

[0066] The dispersion medium used in the present invention is water and an organic solvent. Examples of organic solvents that have 1 to 10 carbon atoms include methanol, ethanol, 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.

[0067] Ethers are linear or cyclic aliphatic ethers having 3 to 30 carbon atoms, such as diethyl ether and tetrahydrofuran. Esters are linear or cyclic esters having 2 to 30 carbon atoms, and examples include ethyl acetate, n-butyl acetate, sec-butyl 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. Ketones are linear or cyclic aliphatic ketones having 3 to 30 carbon atoms, such as methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, diisopropyl ketone, diisobutyl ketone, methyl amyl ketone, and cyclohexanone.

[0068] Amides are aliphatic amides with 3 to 30 carbon atoms, such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and N-ethylpyrrolidone. Hydrocarbons are linear or cyclic aliphatic or aromatic hydrocarbons having 6 to 30 carbon atoms, such as hexane, heptane, octane, nonane, decane, benzene, toluene, and xylene.

[0069] In the present invention, a composition (varnish) is obtained that contains core-shell type metal oxide particles (C) and a thermosetting or photocurable resin. The composition of the present invention can be further mixed with a thermosetting or photocuring resin to produce a varnish.

[0070] The present invention provides a film-forming composition containing the above-mentioned organic solvent sol and organic resin. The film-forming composition can be obtained by removing the organic solvent from the organic solvent sol to obtain a film-forming composition containing core-shell type metal oxide particles (C) and organic resin. In the case of a thermosetting film-forming composition as described above, it is possible to add a thermosetting agent in an amount of 0.01 to 50 phr or 0.01 to 10 phr relative to a functional group-containing resin such as an epoxy group or a (meth)acryloyl group. For example, the thermosetting agent can be contained in an amount of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, relative to a functional group such as an epoxy group or a (meth)acryloyl group. The equivalent amount of the thermosetting agent relative to the curable resin is expressed as the equivalent ratio of the thermosetting agent to the functional group.

[0071] Examples of thermosetting agents include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polymer mercaptans, acid anhydrides, thermal radical generators, and thermal acid generators. Radical-generating curing agents, acid anhydride-based curing agents, and amine-based curing agents are particularly preferred.

[0072] Although these thermosetting agents can be used by dissolving them in a solvent even if they are solid, evaporation of the solvent can lead to a decrease in density of the cured product, the formation of pores, a decrease in strength, and a decrease in water resistance. Therefore, it is preferable that the curing agent itself be liquid at room temperature and atmospheric pressure. Examples of phenolic resins include phenol novolac resins and cresol novolac resins.

[0073] Examples of amine-based curing agents include piperidine, N,N-dimethylpiperazine, triethylenediamine, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, mensendiamine, isophoronediamine, diaminodicyclohexylmethane, 1,3-diaminomethylcyclohexane, xylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and diethyltoluenediamine. Among these, liquid diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, mensendiamine, isophoronediamine, diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, diethyltoluenediamine, etc., can be preferably used.

[0074] Polyamide resins are produced by the condensation of dimer acid and polyamine, and are polyamidoamines having a primary amine and a secondary amine in their molecules.

[0075] Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and epoxyimidazole adduct.

[0076] Polymercaptans are, for example, those in which mercaptan groups are present at the ends of polypropylene glycol chains or polyethylene glycol chains, and are preferably in liquid form.

[0077] As acid anhydride-based curing agents, anhydrides of compounds having multiple carboxyl groups in one molecule are preferred. Examples of these acid anhydride-based curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bistrimellitate, glycerol trimellitate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylcyclohexendicarboxylic anhydride, and chloride anhydride.

[0078] Among these, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, methylhexahydrophthalic anhydride, and mixtures of hexahydrophthalic anhydride and methylhexahydrophthalic anhydride are preferred, as they are liquid at room temperature and atmospheric pressure. These liquid acid anhydrides have a viscosity of approximately 10 mPa·s to 1000 mPa·s when measured at 25°C.

[0079] Examples of thermal radical generators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methylpropionic acid)dimethyl, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, tert-butyl hydroperoxide, cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, and benzoyl peroxide. These can be obtained from Tokyo Chemical Industry Co., Ltd. Examples of thermal acid generators include sulfonium salts and phosphonium salts, but sulfonium salts are preferred. The following compounds are examples.

[0080] [ka]

[0081] R can be an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 20 carbon atoms, with alkyl groups having 1 to 12 carbon atoms being particularly preferred. Furthermore, when obtaining the above-mentioned cured product, a curing aid may be used in combination as appropriate. Examples of curing aids include organophosphorus compounds such as triphenylphosphine and tributylphosphine, quaternary phosphonium salts such as ethyltriphenylphosphonium bromide and methyltriphenylphosphonium diethyl phosphate, 1,8-diazabicyclo(5,4,0)undecane-7-ene, a salt of 1,8-diazabicyclo(5,4,0)undecane-7-ene and octic acid, zinc octyolate, and quaternary ammonium salts such as tetrabutylammonium bromide. These curing aids can be included in a ratio of 0.001 to 0.1 parts by mass per 1 part by mass of the curing agent.

[0082] The composition is obtained by mixing a resin, a hardener, and optionally a curing aid to obtain a thermosetting varnish. These can be mixed in a reaction vessel using a stirring blade or kneader. The resulting thermosetting varnish is a curable film-forming composition and has an appropriate viscosity for use, for example, as a liquid sealant. The liquid thermosetting film-forming composition can be adjusted to any viscosity and can be partially sealed at any point on an LED or the like for use as a transparent sealant by casting, potting, dispensing, printing, etc. An epoxy resin cured body can be obtained by directly mounting the liquid thermosetting composition onto an LED or the like in liquid form using the method described above, and then drying and curing it.

[0083] A thermosetting coating composition (thermosetting varnish) is applied to a substrate and heated at a temperature of 80 to 200°C to obtain a cured product. In the case of a photocurable resin composition in the above-mentioned film-forming composition, a photocuring agent (photoradical generator, photoacid generator) can be added to a functional group-containing resin such as an epoxy group or a (meth)acryloyl group in an amount of 0.01 to 50 phr, or in an amount of 0.01 to 10 phr. For example, the photocuring agent (photoradical generator, photoacid generator) can be contained in an amount of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, relative to a functional group such as an epoxy group or a (meth)acryloyl group. The equivalent amount of the photocuring agent relative to the curable resin is expressed as the equivalent ratio of the photocuring agent to the functional group.

[0084] The photoradical generator is not particularly limited as long as it generates radicals directly or indirectly upon light irradiation. Examples of photoradical generators and photoradical polymerization initiators include imidazole compounds, diazo compounds, bisimidazole compounds, N-arylglycine compounds, azide compounds, titanocene compounds, aluminate compounds, organic peroxides, N-alkoxypyridinium salt compounds, and thioxanthone compounds.

[0085] Examples of diazo compounds include 1-diazo-2,5-diethoxy-4-p-tolylmercaptobenzeneborofluoride, 1-diazo-4-N,N-dimethylaminobenzene chloride, and 1-diazo-4-N,N-diethylaminobenzeneborofluoride.

[0086] Examples of bisimidazole compounds include 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)1,2'-bisimidazole and 2,2'-bis(o-chlorophenyl)4,5,4',5'-tetraphenyl-1,2'-bisimidazole. Examples of azide compounds include p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, 4,4'-diazidochalcone, 4,4'-diazidodiphenyl sulfide, and 2,6-bis(4'-azidobenzal)-4-methylcyclohexanone.

[0087] Examples of titanocene compounds include dicyclopentadienyl-titanium-dichloride, dicyclopentadienyl-titanium-bisphenyl, dicyclopentadienyl-titanium-bis(2,3,4,5,6-pentafluorophenyl), dicyclopentadienyl-titanium-bis(2,3,5,6-tetrafluorophenyl), dicyclopentadienyl-titanium-bis(2,4,6-trifluorophenyl), dicyclopentadienyl-titanium-bis(2,6-difluorophenyl), and dicyclopentadienyl Examples include titanium-bis(2,4-difluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,3,4,5,6-pentafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,3,5,6-tetrafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,6-difluorophenyl), and dicyclopentadienyl-titanium-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)-phenyl).

[0088] Other examples of photoradical generators include 1,3-di(tert-butyldioxycarbonyl)benzophenone, 3,3',4,4'-tetrakis(tert-butyldioxycarbonyl)benzophenone, 3-phenyl-5-isoxazolone, 2-mercaptobenzimidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone.

[0089] These photoradical polymerization agents can be obtained, for example, as Irgacure TPO (component: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) manufactured by BASF (c1-1-1), Omnirad819 (component: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) manufactured by IGM Resins (c1-1-2), and Irgacure 184 (component: 1-hydroxycyclohexylphenyl ketone) manufactured by IGM Resins (c1-1-3).

[0090] [ka]

[0091] The photoacid generator is not particularly limited as long as it generates acid directly or indirectly upon light irradiation. Specific examples of photoacid generators include triazine compounds, acetophenone derivative compounds, disulfone compounds, diazomethane compounds, sulfonic acid derivative compounds, iodonium salts, sulfonium salts, phosphonium salts, selenium salts and other onium salts, metallocene complexes, and iron arene complexes.

[0092] The onium salt used as the above-mentioned photoacid generator is an iodonium salt such as diphenyliodonium chloride, diphenyliodonium trifluoromethanesulfate, diphenyliodonium mesylate, diphenyliodonium tosylate, diphenyliodonium bromide, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsenate, bis(p-tert-butylphenyl)iodonium hexafluorophosphate, bis(p-tert-butylphenyl)iodonium mesylate, bis(p-tert-butylphenyl)iodonium tosylate, bis(p-tert-butylphenyl)iodonium trifluoromethanesulfate, bis(p-tert-butylphenyl)iod Examples include bis(alkylphenyl)iodonium salts such as bis(p-t-butylphenyl)iodonium chloride, bis(p-chlorophenyl)iodonium chloride, bis(p-chlorophenyl)iodonium tetrafluoroborate, and bis(4-t-butylphenyl)iodonium hexafluorophosphate, alkoxycarbonylalkoxy-trialkylaryliodonium salts (e.g., 4-[(1-ethoxycarbonyl-ethoxy)phenyl]-(2,4,6-trimethylphenyl)-iodonium hexafluorophosphate), and bis(alkoxyaryl)iodonium salts (e.g., bis(alkoxyphenyl)iodonium salts such as (4-methoxyphenyl)phenyliodonium hexafluoroantimonate).

[0093] Examples of sulfonium salts include triphenylsulfonium chloride, triphenylsulfonium bromide, tri(p-methoxyphenyl)sulfonium tetrafluoroborate, tri(p-methoxyphenyl)sulfonium hexafluorophosphonate, tri(p-ethoxyphenyl)sulfonium tetrafluoroborate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, and other triphenylsulfonium salts, as well as sulfonium salts such as (4-phenylthiophenyl)diphenylsulfonium hexafluoroantimonate, (4-phenylthiophenyl)diphenylsulfonium hexafluorophosphate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluoroantimonate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluorophosphate, and (4-methoxyphenyl)diphenylsulfonium hexafluoroantimonate.

[0094] 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-chlorobenzenediazonium hexafluorophosphate, and benzyltriphenylphosphonium hexafluoroantimonate.

[0095] Other examples include selenium salts such as triphenylselenium hexafluorophosphate and metallocene complexes such as (η5 or η6-isopropylbenzene)(η5-cyclopentadienyl)iron(II) hexafluorophosphate.

[0096] In addition, the following compounds can also be used as photoacid generators.

[0097] [ka]

[0098] [ka]

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] Sulfonium salt compounds and iodonium salt compounds are preferred as photoacid generators. The anionic species is CF3SO3. - , C4F9SO3 - , C8F 17 SO3 - Camphor sulfonate anion, tosylate anion, BF4 - PF6 -AsF6 - and SbF6 - These are some examples. Anionic species such as phosphorus hexafluoride and antimony hexafluoride, which exhibit strong acidity, are particularly preferred.

[0107] The film-forming composition of the present invention may optionally contain conventional additives. Examples of such additives include pigments, colorants, thickeners, sensitizers, defoamers, coatability improvers, lubricants, stabilizers (such as antioxidants, heat stabilizers, and light stabilizers), plasticizers, dissolution accelerators, fillers, and antistatic agents. These additives may be used individually or in combination of two or more.

[0108] Examples of methods for applying the coating composition of the present invention include flow coating, spin coating, spray coating, screen printing, casting, bar coating, curtain coating, roll coating, gravure coating, dipping, and slitting.

[0109] In this invention, a varnish (film-forming composition) can be applied to a substrate and cured by light irradiation or heat curing. Heating can also be performed before and after light irradiation. The thickness of the coating film can be selected from a range of approximately 0.01 μm to 10 mm, depending on the application of the cured material. For example, when used for photoresists, it can be approximately 0.05 to 10 μm (especially 0.1 to 5 μm); when used for printed circuit boards, it can be approximately 5 μm to 5 mm (especially 100 μm to 1 mm); and when used for optical thin films, it can be approximately 0.1 to 100 μm (especially 0.1 to 10 μm).

[0110] When obtaining a transparent coating, the visible light transmittance of the coating can be 80% or more, or 90% or more, typically 90-96%.

[0111] When using a photoacid generator, the light used for irradiation or exposure may be, for example, gamma rays, X-rays, ultraviolet light, or visible light, and is usually visible light or ultraviolet light, especially ultraviolet light. The wavelength of the light is, for example, 150 to 800 nm, preferably 150 to 600 nm, and more preferably 150 to 400 nm. The amount of irradiation light varies depending on the thickness of the coating film, but is, for example, 2 to 20,000 mJ / cm². 2 Preferably 5 to 5000 mJ / cm² 2 The degree can be adjusted accordingly. The light source can be selected according to the type of light to be 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, LED lamps, laser light (helium-cadmium laser, excimer laser, etc.) can be used. The curing reaction of the composition proceeds upon such light irradiation.

[0112] When using a thermal acid generator, or when using a photoacid generator and heating the coating film after light irradiation as needed, the heating is performed at, for example, 60 to 350°C, preferably around 100 to 300°C. The heating time can be selected from a range of 3 seconds or more (for example, 3 seconds to 5 hours), for example, 5 seconds to 2 hours, preferably 20 seconds to 30 minutes, and usually 1 minute to 3 hours (for example, 5 minutes to 2.5 hours).

[0113] Furthermore, when forming patterns or images (for example, when manufacturing printed circuit boards), the coating film formed on the substrate may be pattern-exposed. This pattern exposure may be performed by scanning with laser light or by irradiating with light through a photomask. The un-irradiated areas (unexposed parts) generated by such pattern exposure can be developed (or dissolved) with a developer to form a pattern or image.

[0114] Alkaline aqueous solutions or organic solvents can be used as developing solutions. 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 quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and aqueous solutions of amines such as ethanolamine, propylamine, and ethylenediamine.

[0115] The aforementioned alkaline developer is generally an aqueous solution of 10% by mass or less, preferably an aqueous solution of 0.1 to 3.0% by mass. Furthermore, alcohols or surfactants can be added to the developer, preferably in amounts of 0.05 to 10 parts by mass per 100 parts by mass of the developer. Among these, an aqueous solution of tetramethylammonium hydroxide of 0.1 to 2.38% by mass can be used.

[0116] Furthermore, as the developing solution, general organic solvents can be used, 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 one or more of these can be used as a mixture. Propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl lactate, etc., are particularly preferred.

[0117] In the present invention, adhesion promoters can be added to improve adhesion to the substrate after development. These adhesion promoters include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane; alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane; silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole; vinyltrichlorosilane, 3-chloropropyltrimethoxysilane, and 3 Examples of adhesion promoters include silanes such as aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-(N-piperidinyl)propyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and ureas such as 1,1-dimethylurea and 1,3-dimethylurea, or thiourea compounds. One or more of the above adhesion promoters can be used in combination. The amount of these adhesion promoters added is usually 18% by mass or less, preferably 0.0008 to 9% by mass, and more preferably 0.04 to 9% by mass, in terms of solid content.

[0118] The present invention may include a sensitizer. Examples of usable sensitizers include anthracene, phenothiazene, perylene, thioxanthone, and benzophenonethioxanthone. Furthermore, examples of sensitizing dyes include thiopyrillium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, and pyrylium salt dyes. Particularly preferred are anthracene-based sensitizers, which, when used in combination with a cationic curing catalyst (radiosensitive cationic polymerization initiator), dramatically improve sensitivity and also possess radical polymerization initiation capabilities. In the hybrid type of the present invention that uses both the cationic curing system and the radical curing system, the catalyst species can be simplified. Specific anthracene compounds that are effective include dibutoxyanthracene and dipropoxyanthraquinone. The amount of sensitizer added is 0.01 to 20% by mass, preferably 0.01 to 10% by mass, relative to the solid content.

[0119] The composition of the present invention can be photocured or thermocured using a photoradical generator, a thermal radical generator, a photoacid generator, or a thermal acid generator. When a photoacid generator or a thermal acid generator is used, for example, conventional epoxy curing agents (e.g., amines or acid anhydrides) are not used, or if they are used, their content is extremely low, thus improving the storage stability of the composition.

[0120] Curing by UV irradiation can be applied to materials (equipment) that are sensitive to heat.

[0121] Thermosetting materials and photocuring materials using the coating-forming composition of the present invention have characteristics such as rapid hardening, transparency, and low curing shrinkage, and can be used for coating and bonding electronic components, optical components (anti-reflective coatings), and precision mechanical components.

[0122] The above composition (varnish) can be suitably used as a hard coat agent or a nanoimprint composition.

[0123] Furthermore, it can be used for other applications such as bonding optical elements like lenses in mobile phones and cameras, light-emitting diodes (LEDs), and semiconductor lasers (LDs), liquid crystal panels, biochips, camera lenses and prisms, magnetic components in hard drives for personal computers, pickups in CD and DVD players (the part that captures light information reflected from the disc), speaker cones and coils, motor magnets, circuit boards, electronic components, and internal engine parts for automobiles.

[0124] For hard coating materials used to protect surfaces such as automobile bodies, lamps and electrical appliances, building materials, and plastics, it can be applied to, for example, automobile and motorcycle bodies, headlight lenses and mirrors, plastic lenses for eyeglasses, mobile phones, game consoles, optical films, and ID cards.

[0125] For ink materials used to print on metals such as aluminum and plastics, applications include inks for printing on cards such as credit cards and membership cards, switches and keyboards in electrical appliances and office equipment, and inkjet printer inks for CDs, DVDs, etc.

[0126] Examples of applications include the creation of complex three-dimensional objects by curing resin in combination with 3D CAD, applications to stereolithography for the production of industrial product models, and applications to optical fiber coating, bonding, optical waveguides, and thick film resists. Furthermore, the coating-forming composition of the present invention can be suitably used as an insulating resin for electronic materials such as anti-reflective films, semiconductor encapsulating materials, adhesives for electronic materials, diffractive optical element materials, printed circuit board materials, interlayer insulating film materials, and encapsulating materials for power modules, as well as an insulating material used in high-voltage equipment such as generator coils, transformer coils, and gas-insulated switchgear. [Examples]

[0127] The present invention will be described in further detail below based on reference examples, manufacturing examples, examples, and comparative examples, but the present invention is not limited in any way by these examples.

[0128] [Total metal oxide concentration] The sol was weighed using a crucible, and the solvent was removed by heating at 110°C for 30 minutes to pre-dry it. This was then calcined at 600°C for 30 minutes. The crucible was weighed, and the total metal oxide concentration (mass%) was calculated from the mass of the residue.

[0129] [Average particle diameter by dynamic light scattering (dynamic light scattering particle diameter)] The sol was diluted with a dispersion solvent, and the results were measured using a dynamic light scattering analyzer (Malvern Instruments Ltd., trade name Zeta-Sizer) with the solvent parameters. The Z-mean particle size was used as the dynamic light scattering particle size.

[0130] [Average primary particle size] Using a transmission electron microscope (JEOL Ltd., product name JEM-F200), we imaged the particles, determined the particle size distribution of 500 arbitrary particles, and calculated the average primary particle diameter (equivalent to a circle), aspect ratio, and standard deviation σ.

[0131] [TiO2 mass ratio in particles] The sol was dried on a hot plate at 110°C, and then ground using a mortar and pestle for 15 minutes to obtain a dried powder. This dried powder was measured using an X-ray fluorescence spectrometer (manufactured by Rigaku Co., Ltd., product name Supermini200) to determine the mass ratio (mass%) of TiO2 in the particles.

[0132] [X-ray diffraction measurement] The sol was dried on a hot plate at 110°C, and then ground using a mortar and pestle for 15 minutes to obtain a dried powder. This dried powder was measured using an XRD device (Rigaku Co., Ltd., product name MiniFlex600) to obtain an X-ray diffraction pattern.

[0133] [Refractive index of particles] The refractive index of particles in the sol was measured using the following procedure i) to iii). i) Preparation of varnish containing particulate methanol dispersion 20.00 g of 3-glycidoxypropyltrimethoxysilane (Momentive, trade name SILQUEST A-187T) was weighed into a plastic container, and 18.57 g of methanol and 4.57 g of 0.01 N hydrochloric acid aqueous solution were added thereto. The mixture was stirred at room temperature for 5 hours. 6.00 g of a previously prepared methanol solution of 2,4-aluminum pentanedione (Al(acac)3) (10% by mass Al(acac)3) was added as a curing agent, and the mixture was stirred for 10 minutes to prepare a partial hydrolysate of 3-glycidoxypropyltrimethoxysilane (concentration: 43% by mass). A total of 25.00 g of partially hydrolyzed 3-glycidoxypropyltrimethoxysilane, a particle dispersion sol, water, methanol, and 0.25 g of a methanol solution (10% by mass of L-7604) of a leveling agent (DOWSIL trade name, L-7604) were weighed into a brown bottle and stirred at room temperature for 30 minutes to prepare a varnish containing a particle organic dispersion sol (solid content concentration: 10.0% by mass, particle content: 50 phr, 100 phr, 150 phr).

[0134] ii) Preparation of particle-containing film i) Approximately 0.5 mL of the particulate methanol dispersion varnish obtained in i) was dropped onto a UV-O3 treated Si substrate, and coated using a spin coater (Mikasa Corporation, product name Opticoat MS-B100) to a film thickness of 1.0 μm after coating. Then, the varnish was heated on a hot plate at 80°C for 5 minutes and heat-treated in an oven at 120°C for 1 hour to prepare particulate films (particulate amounts: 50 phr, 100 phr, 150 phr).

[0135] iii) Measurement of refractive index of particle-containing film, calculation of refractive index of particles The refractive indices of the particle-containing films obtained in ii) (particle amounts: 50 phr, 100 phr, 150 phr) were measured using an ellipsometer (multi-incidence angle spectroscopic ellipsometer, product name VASE, manufactured by J.A. Woolam Japan Co., Ltd.). Separately, the refractive index of a particle-free film prepared in the same manner using only the partial hydrolysate of 3-glycidoxypropyltrimethoxysilane was also measured. The refractive indices of the measured particle-containing films were plotted against the particle amount, and the particle refractive index was determined by extrapolating so that the particle amount was 100% by mass.

[0136] [Evaluation of lightfastness of dispersion] A sample was prepared by mixing a dispersion containing metal oxide particles at a solid content of 0.5% by mass in a water / methanol dispersion with a mass ratio of 1 / 1, with a 0.02% by mass dye (sunset yellow) solution in glycerin, in a mass ratio of 1 / 3. This sample was then placed in a quartz cell measuring 1 mm in length, 1 cm in width, and 5 cm in height, and sealed. Finally, an ultraviolet lamp (manufactured by AS ONE Co., Ltd., product name SLUV-6) with a selected wavelength range of I-line (wavelength 365 nm) was used to irradiate the sample at an intensity of 0.4 mW / cm². 2 Ultraviolet light was irradiated for 180 minutes at a wavelength of 365 nm. Before and after UV irradiation, the respective absorbances of the sample at a wavelength of 490 nm (A0 and A0) 180 The absorbance at a wavelength of 490 nm before irradiation with the I line (wavelength 365 nm) was measured using a UV-Vis spectrophotometer (Shimadzu Corporation, product name UV-3600), and the rate of fading of the dye was calculated from the following formula. (A0) shows the absorbance at a wavelength of 490 nm before irradiation with the I line (wavelength 365 nm), and (A 180 The figure shows the absorbance at a wavelength of 490 nm after irradiation with the I-line (wavelength 365 nm) for 180 minutes. Fading rate (%) = (A 180 ) / (A0)×100

[0137] Furthermore, the photocatalytic activity of the particles was evaluated based on the following criteria. Particles with a lower rate of discoloration change indicate that their photocatalytic activity is suppressed. ○: Discoloration rate less than 10% ×: Fading rate of 10% or more

[0138] Furthermore, the cured films obtained in the examples and comparative examples were deposited and evaluated using the method described below.

[0139] (1) Film thickness, film refractive index The reflectance of a hardened film formed on a glass substrate was measured using a reflectance meter (Olympus Corporation, product name USPM-RU). The film thickness and refractive index of the hardened film were calculated from the measured reflectance using optical simulation.

[0140] (2) Haze The presence or absence of cloudiness in the hardened film formed on the glass substrate was examined using a spectroscopic haze meter (product name SH7000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0141] (3) Lightfastness Using an ultraviolet fluorescent lamp type accelerated weathering tester (Q-Lab, product name QUV) equipped with a UV-A lamp, a test was conducted at 0.89 W / m². 2 Under the condition of (340nm), a cured film formed on a glass substrate was irradiated with ultraviolet light for 6 hours. The criteria for evaluation are as follows: When the initial film thickness is d0 and the film thickness after lightfastness evaluation is d, Film thickness change rate (%) = (d0 - d) / d0 × 100 ○: Film thickness change rate is less than 5% ×: Film thickness change rate is 5% or more.

[0142] (4) Imprintability A varnish containing a dispersion of granular propylene glycol monomethyl ether (PGME) was spin-coated onto a quartz substrate, and a film was prepared by desolvating the varnish by heating it on a hot plate at 100°C for 2 minutes. The obtained film was cured using a nanoimprinter (product name NM-0801HB, manufactured by Meisho Kiko Co., Ltd.) while a release-treated quartz mold (product name DTM-2-1, manufactured by Kyodo International Co., Ltd.) was pressed onto it, transferring the uneven pattern while irradiating it with ultraviolet light. The mold was peeled off the obtained cured film, and the formed pattern was observed using a scanning electron microscope (SEM, JEOL Ltd., product name JSM-6010LV). The criteria for judgment are as follows. ○: Pattern is transferred, good imprintability. ×: Pattern is not transferred, resulting in poor imprintability.

[0143] (Manufacturing Example 1): Preparation of core titanium oxide-tin oxide composite metal oxide particles (a1) 171.3 g of a 35% by mass aqueous solution of tetraethylammonium hydroxide was dissolved in 130 g of pure water, and then 5.2 g of metastanic acid (containing 4.4 g in terms of SnO2), 166.7 g of titanium tetraisopropoxide (containing 46.8 g in terms of TiO2), and 38.5 g of oxalic acid dihydrate were added under stirring. The mixed solution was held at 80°C for 2 hours, and then held at 95°C for 5 hours while adding pure water to maintain a constant liquid level to prepare a dispersion of core titanium oxide-stannic oxide composite metal oxide particles (a1). The resulting sol had a pH of 4.6, a total metal oxide concentration (TiO2 and SnO2) of 9.4% by mass, an average particle diameter of 12 nm by dynamic light scattering, an average primary particle diameter of 8 nm by transmission electron microscopy, and an aspect ratio of 1.8.

[0144] (Manufacturing Example 2): Preparation of silicon dioxide-stannic oxide composite metal oxide (b1) to be used as a coating. 77.2 g of JIS No. 3 sodium silicate (containing 29.8% by mass in terms of SiO2) was dissolved in 668.8 g of pure water, and then 20.9 g of sodium stannate NaSnO3·H2O (containing 55.1% by mass in terms of SnO2) was dissolved in it. The resulting aqueous solution was passed through a column packed with hydrogen-type cation exchange resin (Amberlite (product name) IR-120B). Then, 7.2 g of diisopropylamine was added to the resulting aqueous dispersion sol. The result was an alkaline aqueous dispersion of silicon dioxide-stannous oxide composite metal oxide (b1) with a pH of 8.0 and a total metal oxide concentration (SnO2, and SnO2) of 2.7% by mass.

[0145] (Manufacturing Example 3): Preparation of silicon dioxide (b2) to be used as a coating 77.2 g of JIS No. 3 sodium silicate (containing 29.8% by mass in terms of SiO2) was dissolved in 689.7 g of pure water. The resulting aqueous solution was passed through a column packed with hydrogen-type cation exchange resin (Amberlite (product name) IR-120B). Then, 4.6 g of diisopropylamine was added to the resulting aqueous dispersion sol. The result was an alkaline aqueous dispersion of silicon dioxide (b1) with a pH of 8.3 and a total metal oxide concentration (silicon dioxide concentration) of 2.7% by mass.

[0146] (Example 1) To 276.5 g of an aqueous dispersion of titanium dioxide-stannous oxide composite metal oxide particles (a1) obtained in Production Example 1, 261.7 g of 35% by mass aqueous solution of tetraethylammonium hydroxide, 255 g of titanium tetraisopropoxide (containing 71.6 g in terms of TiO2), and 58.8 g of oxalic acid dihydrate were added under stirring. The mixed solution was held at 80°C for 2 hours, and then held at 95°C for 5 hours while adding pure water to maintain a constant liquid level. Next, the mixed solution was placed in a glass-lined autoclave container and hydrothermally treated at 140°C for 5 hours to promote particle growth. The resulting sol was desalted and washed by ultrafiltration, and 2.4 g of 35% tetraethylammonium hydroxide was added. The sol was obtained by passing the solution through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.). The obtained sol was an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a2) coated with titanium oxide, with a pH of 12.1, a total metal oxide concentration (TiO2, SnO2, etc.) of 3.5% by mass, and an average primary particle size of 12 nm as observed by transmission electron microscopy. X-ray diffraction measurements of the powder obtained by drying this sol at 110°C confirmed that it was a rutile-type crystal.

[0147] 35.1 g of zirconium oxychloride (containing 7.0 g in ZrO2 equivalent) was diluted with 475 g of pure water to prepare 510.1 g of an aqueous solution of zirconium oxychloride. 1576.5 g of an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a2) coated with titanium oxide was added under stirring. The dispersion was then heated at 95°C for 5 hours to hydrolyze the solution, yielding an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles in which a thin film layer of zirconium oxide was further formed on the titanium oxide-coated surface. 2073.0 g of the obtained aqueous dispersion was added under stirring to 565.3 g of an aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the solution was passed through a column packed with 500 ml of anion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.). Next, the aqueous dispersion after passing through the solution was heated at 150°C for 4 hours, and then passed through a column packed with cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Co., Ltd.). 3.1 g of tri-n-pentylamine was added to the obtained aqueous dispersion, and it was concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannous oxide-zirconium oxide composite metal oxide particles (c1) coated with silicon dioxide-stannous oxide composite metal oxide. The obtained aqueous dispersion was subjected to a rotary evaporator to replace the dispersion medium with methanol to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 5.2, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.0 mass%, and a viscosity of 5.0 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 70%, the average primary particle diameter measured by transmission electron microscopy was 15 nm, the aspect ratio was 1.8, the standard deviation σ was 2 nm, the refractive index was 2.2, and the dispersion's lightfastness was rated as ○.

[0148] (Example 2) To 471 g of an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles (a1) obtained in Production Example 1, 203.5 g of 35% by mass aqueous solution of tetraethylammonium hydroxide, 198.4 g of titanium tetraisopropoxide (containing 55.8 g in terms of TiO2), and 45.8 g of oxalic acid dihydrate were added under stirring. The mixed solution was held at 80°C for 2 hours, and then held at 95°C for 5 hours while adding pure water to maintain a constant liquid level. Next, the mixed solution was placed in a glass-lined autoclave container and hydrothermally treated at 140°C for 5 hours to grow the particles. The obtained sol was desalted and washed by ultrafiltration, and 2.5 g of 35% tetraethylammonium hydroxide was added. The sol was obtained by passing the solution through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.). The obtained sol was an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles coated with titanium dioxide, with a pH of 12.0, a total metal oxide concentration (TiO2, SnO2, etc.) of 5.0% by mass, and an average primary particle size of 10.5 nm as observed by transmission electron microscopy. X-ray diffraction measurements of the powder obtained by drying this sol at 110°C confirmed that it was a rutile-type crystal.

[0149] 36.9 g of zirconium oxychloride (containing 7.4 g in ZrO2 equivalent) was diluted with 876.4 g of pure water to prepare 913.3 g of an aqueous solution of zirconium oxychloride. 1000 g of an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles coated with titanium oxide was added under stirring. The solution was then heated at 95°C for 5 hours to hydrolyze it, yielding an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles in which a thin film layer of zirconium oxide was further formed on the titanium oxide-coated surface. 1913 g of the obtained aqueous dispersion was added under stirring to 619.5 g of an aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the solution was passed through a column packed with 500 ml of anion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.). Next, the aqueous dispersion after passing through the column was heated at 150°C for 4 hours, and then passed through a column packed with cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Co., Ltd.). 1.7 g of tri-n-pentylamine was added to the obtained aqueous dispersion, and it was concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannous oxide-zirconium oxide composite metal oxide particles (C2) coated with silicon dioxide-stannous oxide composite metal oxide. The obtained aqueous dispersion was then subjected to a rotary evaporator to replace the dispersion medium with methanol to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 5.0, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.1% by mass, and a viscosity of 5.0 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 65% by mass, the average primary particle diameter measured by transmission electron microscopy was 13 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.12, and the lightfastness of the dispersion was rated as ○.

[0150] (Example 3) 1968.5 g of an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles, prepared in Example 1, in which a thin zirconium oxide film layer was formed on a surface coated with titanium oxide, was added under stirring to 648.1 g of an aqueous dispersion of alkaline silicon dioxide (b2) prepared in Production Example 3, and the dispersion was passed through a column packed with 500 ml of anion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Corporation). The aqueous dispersion after passing through was then heated at 150°C for 4 hours and passed through a column packed with cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Corporation). 2.7 g of tri-n-pentylamine was added to the obtained aqueous dispersion, and the total metal oxide concentration was concentrated to 20% by mass by ultrafiltration to obtain an aqueous dispersion of silicon dioxide-coated titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles (c4). Next, 338 g of methanol and 6.7 g of 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KBM-503) were added, and the mixture was heated at 60°C for 5 hours to modify the surface of the particles. The resulting aqueous dispersion was then subjected to a rotary evaporator to replace the dispersion medium with methanol to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 4.8, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.0% by mass, and a viscosity of 5.1 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 64% by mass, the average primary particle diameter measured by transmission electron microscopy was 14 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.10, and the dispersion's lightfastness was rated as ○.

[0151] (Example 4) To 1428.5 g of an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles (a2) coated with titanium dioxide obtained in Production Example 1, 1428.5 g of methanol and 41.1 g of orasilicate (containing 29.8% by mass in terms of SiO2) were added under stirring. This was heated and stirred at 50°C for 24 hours to obtain an aqueous dispersion of silicon dioxide-coated titanium dioxide-stannic oxide composite metal oxide particles (c4). The obtained aqueous dispersion was concentrated to a total metal oxide concentration of 20% by mass using a rotary evaporator. Next, 311 g of methanol and 6.2 g of 3-methacryloxypropyltrimethoxysilane were added, and the surface of the particles was modified by heating at 60°C for 5 hours. Subsequently, the dispersion medium was replaced with methanol using a rotary evaporator to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 8.8, a total metal oxide (TiO2, SnO2, and SiO2) concentration of 29.5% by mass, and a viscosity of 5.3 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 79% by mass, the average primary particle diameter measured by transmission electron microscopy was 13 nm, the aspect ratio was 1.8, the standard deviation σ was 2 nm, the refractive index was 2.19, and the dispersion's lightfastness was rated as ○.

[0152] (Example 5) To 100.0 g of the methanol dispersion (c1) obtained in Example 1, 3.0 g of 3-methacryloxypropyltrimethoxysilane was added, and the mixture was heated at 60°C for 5 hours to modify the surface of the particles. The resulting methanol dispersion had a pH of 5.4, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.2% by mass, and a viscosity of 5.1 mPa·s. The TiO2 mass ratio in the particles was 70% by mass, the average primary particle diameter measured by transmission electron microscopy was 15 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.2, and the dispersion's lightfastness was rated as ○.

[0153] (Example 6) 100.0 g of the methanol dispersion (c1) obtained in Example 1 was mixed with 3.0 g of phenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KBM-103), and the mixture was heated at 60°C for 5 hours to modify the surface of the particles. The resulting methanol dispersion had a pH of 5.4, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.1% by mass, and a viscosity of 5.0 mPa·s. The TiO2 mass ratio in the particles was 70% by mass, the average primary particle diameter measured by transmission electron microscopy was 15 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.2, and the lightfastness of the dispersion was rated as ○.

[0154] (Example 7) To 100.0 g of the methanol dispersion (c1) obtained in Example 1, 3.0 g of 2-(allyloxymethyl)acrylate (trimethoxysilyl)propyl (manufactured by Shin-Etsu Chemical Co., Ltd., trade name X-12-1333A) was added, and the surface of the particles was modified by heating at 60°C for 5 hours. The resulting methanol dispersion had a pH of 5.4, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.2% by mass, and a viscosity of 5.1 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 70% by mass, the average primary particle diameter measured by transmission electron microscopy was 15 nm, the aspect ratio was 1.8, the standard deviation σ was 2 nm, the refractive index was 2.2, and the lightfastness of the dispersion was rated as ○.

[0155] (Comparative Example 1) 797.9 g of an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles (a1) obtained in Production Example 1 was placed in a glass-lined autoclave container and subjected to hydrothermal treatment at 140°C for 5 hours. The resulting sol was desalted and washed by ultrafiltration, and 1.9 g of 35% tetraethylammonium hydroxide was added. The sol was passed through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.) to obtain a sol. The obtained sol was an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles without titanium dioxide coating, with a pH of 11.9, a total metal oxide concentration (TiO2, SnO2, etc.) of 5.0 mass%, and an average primary particle size of 8 nm as observed by transmission electron microscopy. X-ray diffraction measurement of the powder obtained by drying this sol at 110°C confirmed that it was a rutile-type crystal.

[0156] 75.1 g of zirconium oxychloride (containing 15 g in ZrO2 equivalent) was diluted with 1425.0 g of pure water to prepare 1500.0 g of an aqueous solution of zirconium oxychloride, and 1499.7 g of an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles was added under stirring. Then, the solution was heated at 95°C for 5 hours to hydrolyze it, and an aqueous dispersion of titanium dioxide-stannic oxide-zirconium oxide composite metal oxide particles was obtained in which a thin film layer of zirconium oxide had been formed. 2978.4 g of the obtained aqueous dispersion was added under stirring to 1333.2 g of an aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the solution was passed through a column packed with 500 ml of anion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.). Next, the aqueous dispersion after passing through the solution was heated at 150°C for 4 hours, and then passed through a column packed with cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Co., Ltd.). 5.4 g of tri-n-pentylamine was added to the obtained aqueous dispersion, and it was concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannous oxide-zirconium oxide composite metal oxide particles (C6) coated with silicon dioxide-stannous oxide composite metal oxide. The obtained aqueous dispersion was then subjected to a rotary evaporator to replace the dispersion medium with methanol to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 5.5, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.5% by mass, and a viscosity of 4.8 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 55% by mass, the average primary particle diameter measured by transmission electron microscopy was 11 nm, the aspect ratio was 1.8, the standard deviation σ was 2 nm, the refractive index was 2.04, and the dispersion's lightfastness was rated as ○.

[0157] (Comparative Example 2) In Production Example 1, the sol was prepared in the same manner except that the amount of tetraethylammonium hydroxide aqueous solution was changed to 221.8 g. The obtained sol had a pH of 5.3, a total metal oxide concentration (TiO2, SnO2, etc.) of 10.2% by mass, an average particle size of 16 nm determined by dynamic light scattering, and an aspect ratio of 3.0 for primary particles observed by transmission electron microscopy, resulting in irregularly shaped particles that grew only in the long axis direction. 735.3 g of this sol was placed in a glass-lined autoclave container and hydrothermally treated at 140°C for 5 hours. The obtained sol was desalted and washed by ultrafiltration, and 1.9 g of 35% tetraethylammonium hydroxide was added. The sol was obtained by passing it through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.). The obtained sol was an aqueous dispersion of deformed titanium oxide-stannic oxide composite metal oxide particles without titanium oxide coating, with a pH of 12.2, a total metal oxide concentration (TiO2, SnO2, etc.) of 4.8% by mass, and an average primary particle size of 12 nm as observed by transmission electron microscopy. X-ray diffraction measurements of the powder obtained by drying this sol at 110°C confirmed that it was a rutile-type crystal.

[0158] 75.1 g of zirconium oxychloride (containing 15 g in ZrO2 equivalent) was diluted with 1425.0 g of pure water to prepare 1500.0 g of an aqueous solution of zirconium oxychloride, and 1562.5 g of an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles was added under stirring. Then, by heating at 95°C for 5 hours to hydrolyze the solution, an aqueous dispersion of titanium dioxide-stannic oxide-zirconium oxide composite metal oxide particles with a thin film layer of zirconium oxide was obtained. 3058.6 g of the obtained aqueous dispersion was added under stirring to 250.0 g of an aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the solution was passed through a column packed with 500 ml of anion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Co., Ltd.). Next, the aqueous dispersion after passing through the solution was heated at 150°C for 4 hours, and then passed through a column packed with cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Co., Ltd.). 2.6 g of tri-n-pentylamine was added to the obtained aqueous dispersion, and it was concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannous oxide-zirconium oxide composite metal oxide particles (c7) coated with silicon dioxide-stannous oxide composite metal oxide. The obtained aqueous dispersion was then subjected to a rotary evaporator to replace the dispersion medium with methanol to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 5.8, a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 30.7% by mass, and a viscosity of 6.5 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 70% by mass, the average primary particle diameter measured by transmission electron microscopy was 15 nm, the aspect ratio was 3.0, the standard deviation σ was 3 nm, the refractive index was 2.2, and the dispersion's lightfastness was rated as ○.

[0159] (Comparative Example 3) To 184.4 g of an aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, 1500.0 g of an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles (a2) coated with titanium dioxide obtained in Example 1 was added under stirring. After heating at 95°C for 3 hours, the mixture was passed through a column packed with cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Co., Ltd.). 1.6 g of tri-n-pentylamine was added to the resulting aqueous dispersion, and the mixture was concentrated by ultrafiltration to obtain an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles (c8) coated with silicon dioxide-stannic oxide composite metal oxide. The resulting aqueous dispersion was subjected to a rotary evaporator with methanol as the dispersion medium to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 5.2, a total metal oxide (TiO2, SnO2, and SiO2, etc.) concentration of 30.4% by mass, and a viscosity of 4.5 mPa·s. Furthermore, the TiO2 mass ratio in the particles was 89% by mass, the average primary particle diameter measured by transmission electron microscopy was 13 nm, the aspect ratio was 1.8, the standard deviation σ was 2 nm, and the refractive index was 2.3. The dispersion's lightfastness was rated as × due to insufficient coating of metal oxides other than titanium dioxide.

[0160] (Comparative Example 4) 200.0 g of an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a2) coated with titanium oxide obtained in Example 1 was mixed with 0.2 g of tri-n-pentylamine and concentrated by ultrafiltration. This aqueous dispersion was then subjected to a rotary evaporator to replace the dispersion medium with methanol to obtain a methanol dispersion of metal oxide particles. This methanol dispersion had a pH of 11.7, a total metal oxide (TiO2, SnO2, etc.) concentration of 25.1% by mass, and a viscosity of 6.3 mPa·s. The TiO2 mass ratio in the particles was 98% by mass, the average primary particle diameter measured by transmission electron microscopy was 12 nm, the aspect ratio was 1.8, the standard deviation σ was 2 nm, and the refractive index was 2.4. Since the dispersion was not coated with metal oxides other than titanium oxide, the lightfastness of the dispersion was rated as ×.

[0161] (Example 8) A methanol dispersion of particles (c1) obtained in Example 1 was subjected to a rotary evaporator to replace the dispersion medium with PGME to obtain a PGME dispersion of particles (c1). This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2, etc.) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 28 nm as determined by dynamic light scattering (DLS).

[0162] (Membrane evaluation) A cured film was prepared using the obtained PGME dispersion by following the procedure below. In a brown bottle equipped with a magnetic stirrer, 0.75 g of a mixture of dipentaerythritol hexa and pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name KAYARAD DPHA) and 1.8 g of PGME were added as a resin binder, and while stirring, 10.98 g of a PGME dispersion of particles (c1) (particle addition amount: 300 phr) was added. Next, 0.0075 g of a photoradical polymerization initiator (manufactured by BASF Corporation, trade name Irgacure OXE01) and 0.10 g of a PGME solution of a polyether-modified silicone surface modifier (manufactured by Dow-Toray Industries, Ltd., trade name DOWSIL® L-7001) (L-7001 concentration: 10.0 mass%) were added, and the mixture was stirred for 0.5 hours to prepare a varnish. Glass substrates are prepared, varnish is applied to them by spin coating, the solvent is evaporated at 100°C for 2 minutes, and then the integrated light intensity is 1000 mJ / cm². 2 The varnish was cured using ultraviolet light from a high-pressure mercury lamp to form a cured film. The resulting cured film had a thickness of 1.0 μm, a refractive index of 1.85, a haze of 0.18%, and a lightfastness rating of "○". Furthermore, the imprintability of the same varnish was evaluated and received a "○" rating.

[0163] (Example 9) A PGME dispersion of particles (c2) was prepared using the methanol dispersion of particles (c2) obtained in Example 2, following the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 23 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.82, a haze of 0.15%, and a lightfastness rating of "○". In addition, when the imprintability was evaluated using the same varnish, it received a rating of "○".

[0164] (Example 10) Instead of the methanol dispersion of particles (c1) obtained in Example 1, a PGME dispersion of particles (c3) surface-modified with 3-methacryloxypropyltrimethoxysilane obtained in Example 3 was used to prepare a PGME dispersion of particles (c3) using the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 20 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.81, a haze of 0.16%, and a lightfastness of "○". In addition, when the imprintability was evaluated using the same varnish, it received a "○" rating.

[0165] (Example 11) Instead of the methanol dispersion of particles (c1) obtained in Example 1, a PGME dispersion of particles (c4) surface-modified with 3-methacryloxypropyltrimethoxysilane obtained in Example 4 was used to prepare a PGME dispersion of particles (c4) using the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 24 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.85, a haze of 0.14%, and a lightfastness rating of "○". In addition, when the imprintability was evaluated using the same varnish, it received a rating of "○".

[0166] (Example 12) Instead of the methanol dispersion of particles (c1) obtained in Example 1, a PGME dispersion of particles (c1) was prepared using the methanol dispersion of particles (c1) surface-modified with 3-methacryloxypropyltrimethoxysilane obtained in Example 5, following the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 18 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.82, a haze of 0.15%, and a lightfastness rating of "○". In addition, when the imprintability was evaluated using the same varnish, it received a rating of "○".

[0167] (Example 13) Instead of the methanol dispersion of particles (c1) obtained in Example 1, a PGME dispersion of particles (c1) was prepared using the methanol dispersion of particles (c1) surface-modified with phenyltrimethoxysilane obtained in Example 6, following the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 17 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.83, a haze of 0.21%, and a lightfastness rating of "○". In addition, when the imprintability was evaluated using the same varnish, it received a rating of "○".

[0168] (Example 14) Instead of the methanol dispersion of particles (c1) obtained in Example 1, a PGME dispersion of particles (c1) was prepared using the methanol dispersion of particles (c1) surface-modified with 2-(allyloxymethyl)acrylate (trimethoxysilyl)propyl obtained in Example 7, following the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 15 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.82, a haze of 0.10%, and a lightfastness rating of "○". In addition, when the imprintability was evaluated using the same varnish, it received a rating of "○".

[0169] (Comparative Example 5) Instead of the methanol dispersion of particles (c1) obtained in Example 1, a PGME dispersion of particles (c6) was prepared using the methanol dispersion of particles (c6) obtained in Comparative Example 1, following the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 17 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used. The obtained cured film had a thickness of 1.1 μm, a refractive index of 1.79, a haze of 0.14%, and a lightfastness rating of "○". In addition, when the imprintability was evaluated using the same varnish, it received a rating of "○".

[0170] (Comparative Example 6) Instead of the methanol dispersion of particles (c1) obtained in Example 1, a PGME dispersion of particles (c7) was prepared using the methanol dispersion of particles (c7) obtained in Comparative Example 2, following the same procedure as in Example 9. This PGME dispersion had a total metal oxide (TiO2, ZrO2, SnO2, and SiO2) concentration of 20.5% by mass and an average particle diameter (dynamic light scattering particle diameter) of 43 nm as determined by dynamic light scattering (DLS). Furthermore, in the film evaluation, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used. The resulting cured film had a high haze content of 0.8%, and a transparent film could not be obtained. Therefore, the thickness and refractive index could not be calculated by optical simulation using reflectivity.

[0171] The core-shell type metal oxide particles obtained in Examples 1 to 7 had an average primary particle diameter of 13-15 nm, a standard deviation σ of 2 nm, an aspect ratio of 1.8, a refractive index of 2.10-2.29, and dispersion lightfastness (○). The cured films of Examples 8 to 14 had a refractive index of 1.81-1.86, a haze of 0.10-0.25, lightfastness (○), and imprintability (○), indicating excellent refractive index, transparency, and lightfastness.

[0172] The core-shell type metal oxide particles obtained in Comparative Example 1 had a refractive index of 2.04, and the cured film in Comparative Example 5 had a refractive index of 1.79, so the refractive index was not sufficient. The core-shell type metal oxide particles obtained in Comparative Example 2 had an aspect ratio of 3.0, and the cured film in Comparative Example 6 had a haze of 0.8%, so the transparency was not sufficient. The core-shell type metal oxide particles obtained in Comparative Examples 3 and 4 had poor lightfastness in the dispersion, so the lightfastness was not sufficient. From the above results, it was found that the core-shell type metal oxide particles of the present invention, by coating the surface of the core metal oxide particles with titanium oxide and further coating this coating with a metal oxide whose main component is a metal oxide other than titanium oxide, allows for adjustment of the primary particle size while maintaining the aspect ratio, and exhibits excellent light resistance, transparency, and processability such as imprinting, as well as a high refractive index. Furthermore, it was found that compositions containing these particles exhibit excellent optical properties. [Industrial applicability]

[0173] The core-shell type metal oxide particles of the present invention are suitable for use as hard coats, UV-cutting layers, anti-reflective coatings, and optical thin films such as diffractive optical elements when compounded with thermosetting or photocurable resins.

Claims

1. Core-shell type metal oxide particles (C) having an average primary particle diameter of 10 to 20 nm, and a standard deviation σ of the circular equivalent particle diameter of the particles when observed with a transmission electron microscope being less than 3 nm.

2. The core-shell type metal oxide particle (C) according to claim 1, wherein the surface of a core metal oxide particle (A1) is coated with a metal oxide (A2) containing titanium oxide, and the coating is further coated with a metal oxide (A3) whose main component is a metal oxide other than titanium oxide, and the metal oxide particle (A1) is a rutile-type titanium oxide containing at least one selected from the group consisting of tin oxide, zirconium oxide, zinc oxide, iron oxide, nickel oxide, and aluminum oxide.

3. The core-shell type metal oxide particle (C) according to claim 2, wherein the metal oxide (A3) comprises at least one metal oxide selected from the group consisting of zirconium oxide, tin oxide, silicon dioxide, zinc oxide, antimony oxide, niobium oxide, tungsten oxide, aluminum oxide, and tantalum oxide, or two or more composite oxides.

4. The core-shell type metal oxide particle (C) according to claim 2, wherein the metal oxide (A3) is a tin oxide-silicon dioxide composite metal oxide.

5. The core-shell type metal oxide particle (C) according to any one of claims 1 to 4, wherein the refractive index of the core-shell type metal oxide particle (C) is 2.1 to 2.

7.

6. TiO ２ Core-shell type metal oxide particles (C) according to any one of claims 1 to 4, comprising 60 to 85% by mass of titanium oxide in conversion.

7. The core-shell type metal oxide particle (C) according to any one of claims 1 to 4, wherein the core-shell type metal oxide particle (C) is further coated with a coating (B).

8. The core-shell type metal oxide particle (C) according to claim 7, wherein the coating (B) is at least one selected from the group consisting of amines (B1), silane compounds (B2), organic acids and organic acid esters (B3), phosphate esters (B4), or surfactants (B5).

9. The core-shell type metal oxide particle (C) according to claim 8, wherein the amine (B1) is a secondary amine and / or tertiary amine having a total number of carbon atoms of 5 to 35.

10. The silane compound (B2) is given by formulas (1) to (3): 【Chemistry 1】 (In formula (1), R １ Each of these is an organic group having an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or a polyether group, an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, or a cyano group, and is bonded to a silicon atom by a Si-C bond, R ２ Each of the following represents an alkoxy group, an acyloxy group, or a halogen group, and a represents an integer from 1 to 3. In equations (2) and (3), R ３ and R ５ Each of these is an alkyl group having 1 to 3 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and is bonded to a silicon atom by a Si-C bond, R ４ and R ６ (wherein 'b' represents an alkoxy group, an acyloxy group, or a halogen group, Y represents an alkylene group, an NH group, or an oxygen atom, b is an integer from 1 to 3, c is an integer of 0 or 1, and d is an integer from 1 to 3.) The core-shell type metal oxide particle (C) according to claim 8, which is a hydrolysate and / or dehydration condensate of at least one silane compound selected from the group consisting of the above.

11. The core-shell type metal oxide particle (C) according to claim 8, wherein the organic acid and organic acid ester (B3) is acetic acid, benzoic acid, oxalic acid, malonic acid, succinic acid, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, or an alkyl, aryl, or arylalkyl ester thereof.

12. The phosphate ester (B4) is given by formulas (4) to (6): 【Chemistry 2】 (In formulas (4) to (6), X １ , X ２ , and X ３ each represents an alkylene group having 2 to 20 carbon atoms, f, h, and j each represents an integer of 1 to 100, e, g, and i each represents an integer of 1 to 3, and Y １ , Y ２ , and Y ３ each represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or a (meth)acrylic group.) The core-shell type metal oxide particles (C) according to claim 8, which is at least one phosphate ester selected from the group consisting of

13. The core-shell type metal oxide particle (C) according to claim 8, wherein the surfactant (B5) is an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant.

14. A core-shell type metal oxide sol comprising core-shell type metal oxide particles (C) and a dispersion medium as described in claim 1.

15. The core-shell type metal oxide sol according to claim 14, wherein the dispersion medium is a dispersion medium consisting of water, alcohol, ether, ester, ketone, amide, hydrocarbon, or a combination thereof.

16. A varnish comprising core-shell type metal oxide particles (C) according to any one of claims 1 to 4 or a core-shell type metal oxide sol according to claim 14 or 15, and a thermosetting and / or photocurable resin.

17. The varnish according to claim 16, wherein the varnish is a varnish for improving lightfastness.

18. The varnish according to claim 16, wherein the varnish is a varnish for hard coats.

19. The varnish according to claim 16, wherein the varnish is a varnish for nanoimprinting.

20. The following steps (i), (ii), and (iii): (i) Step: Adding a precursor raw material of a metal oxide (A2) containing titanium dioxide to a metal oxide sol in which water containing core metal oxide particles (A1) is used as a dispersion medium. (ii) Step: A sol obtained in step (i) containing the core metal oxide particles (A1) and the precursor raw materials of titanium oxide (A2) is heated to coat the surface of the core metal oxide particles (A1) with the titanium oxide-containing metal oxide (A2). (iii) Step: Add a sol containing a metal oxide (A3) whose main component is a metal oxide other than titanium dioxide, with water as the dispersion medium, to the sol obtained in step (ii), and then heat it further in step (iii). A method for producing a core-shell type metal oxide sol according to claim 14 or 15, comprising:

Images