Metal oxide particles having core / shell structure having uniform particle size distribution, and method for producing same

Abstract

Provided are: core / shell-type metal oxide particles which are suitably used for an optical thin film, such as a hard coat, an ultraviolet blocking layer, an anti-reflection film or a diffractive optical element material, have excellent light resistance, transparency and processing properties, e.g. imprinting, and have a high refractive index; and a method for producing the same.　In these core / shell-type metal oxide particles (C), the surface of metal oxide particles (A1) serving as a core is coated with a metal oxide (A2) containing titanium oxide, and the coating layer is further coated with a metal oxide (A3) having a metal oxide other than titanium oxide as the main component. The average primary particle diameter of said core / shell-type metal oxide particles (C) is 10 to 20 nm, and the metal oxide particles (A1) are 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 aluminium oxide.

Description

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

[0001] The present invention relates to core-shell metal oxide particles having an average primary particle size of 10 to 20 nm, in which the surface of a core metal oxide particle is coated with a metal oxide containing titanium oxide, and the coated particle is further coated with a metal oxide mainly composed of a metal oxide other than titanium oxide, and a method for producing the same. More specifically, the present invention relates to core-shell metal oxide particles suitable for use in optical thin films such as hard coats, UV-blocking layers, anti-reflection films, and diffractive optical element materials, which have excellent light resistance, transparency, and processability such as imprinting, and also have a high refractive index, and a method for producing the same.

[0002] Varnishes containing metal oxide particles have traditionally been used to form optical thin films for eyeglass lenses and various displays. For example, the higher the refractive index of the lens substrate, the thinner the eyeglass lens can be made, so a varnish used in a hard coat for eyeglass lenses preferably has a high refractive index. Anti-reflection coatings are typically formed by alternating high-refractive-index and low-refractive-index layers. From the perspective of anti-reflection performance, a varnish used in a high-refractive-index layer preferably has a higher refractive index. Therefore, the higher the refractive index of the metal oxide particles contained in the varnish, the more desirable it is. For example, metal oxides such as titanium oxide, tantalum oxide, zirconium oxide, and tin oxide are known to have high refractive indices. Among these, titanium oxide with a rutile 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 titanium oxide particles (see Patent Documents 1 to 3). Patent Document 1 discloses titanium oxide-containing core-shell metal oxide particles having at least one intermediate layer formed between a titanium oxide-containing core particle and a coating layer formed of a silicon dioxide-stannic oxide composite metal oxide that coats the titanium oxide core particle, the intermediate layer being formed of an oxide of at least one element selected from the group consisting of Si, Al, Sn, Zr, Zn, Sb, Nb, Ta, and W, a composite metal oxide, or a mixture of said oxide and said composite metal oxide. Patent Document 2 discloses rutile-type core-shell metal oxide particles in which a core particle formed of any one of tin oxide, zinc-added titanium oxide, and tin-added titanium oxide is coated with rutile-type titanium oxide. Patent Document 3 discloses TiO ２ Rutile-type titanium oxide particles containing 90% or more by weight of titanium oxide in terms of carbon dioxide equivalent are disclosed.

[0003] Japanese Patent No. 5896178 Japanese Patent Application Laid-Open No. 2008-308386 International Publication No. 2022 / 210973

[0004] However, according to the findings of the present inventors, the titanium oxide-containing core-shell metal oxide particles described in Patent Document 1 use a material with a lower refractive index than titanium oxide for the intermediate layer, which may result in a low refractive index for the core-shell metal oxide particles. Furthermore, the rutile core-shell metal oxide particles described in Patent Document 2 have an outermost layer made of titanium oxide, which may fail to suppress optical activity and result in insufficient light resistance. Furthermore, the rutile titanium oxide particles described in Patent Document 3 have insufficient transparency due to their large dispersed particle size, and may also have insufficient light resistance due to the high amount of titanium oxide in the particles. Therefore, the present invention aims to provide core-shell metal oxide particles that are suitable for use in optical thin films such as hard coats, UV-blocking layers, anti-reflection films, and diffractive optical elements, and that have excellent light resistance, transparency, and processability, such as imprinting, and a high refractive index, as well as 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 primarily composed of a metal oxide other than titanium oxide, and the core-shell metal oxide particles have an average primary particle size of 10 to 20 nm, and a method for producing the same.

[0005] According to a first aspect, the present invention provides core-shell type metal oxide particles (C), which have an average primary particle diameter of 10 to 20 nm and a standard deviation σ of the equivalent circle particle diameters of the particles when observed with a transmission electron microscope of less than 3 nm; and according to a second aspect, the core-shell type metal oxide particles (C) according to the first aspect, which are obtained by coating the surface of a core metal oxide particle (A1) with a metal oxide (A2) containing titanium oxide, and the coating is further coated with a metal oxide (A3) containing a metal oxide other than titanium oxide as a main component, and the metal oxide particles (A1) are 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; According to a third aspect, the core-shell type metal oxide particle (C) according to the first or second aspect, wherein the metal oxide (A3) contains at least one metal oxide or two or more composite oxides 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; according to a fourth aspect, the core-shell type metal oxide particle (C) according to any one of the first to third aspects, wherein the metal oxide (A3) is a tin oxide-silicon dioxide composite metal oxide; according to a fifth aspect, the core-shell type metal oxide particle (C) according to any one of the first to fourth aspects, wherein the refractive index of the core-shell type metal oxide particle (C) is 2.1 to 2.7; and according to a sixth aspect, TiO ２the core-shell type metal oxide particle (C) according to any one of the first to fifth aspects, containing 60 to 85% by mass of titanium oxide in terms of mass equivalent; as a seventh aspect, the core-shell type metal oxide particle (C) according to any one of the first to sixth aspects, in which the core-shell type metal oxide particle (C) is further coated with a coating (B); as an eighth aspect, the core-shell type metal oxide particle (C) according to any one of the first to seventh aspects, in which the coating (B) is at least one selected from the group consisting of an amine (B1), a silane compound (B2), an organic acid and an organic acid ester (B3), a phosphate ester (B4), or a surfactant (B5); as a ninth aspect, the core-shell type metal oxide particle (C) according to the eighth aspect, in which the amine (B1) is a secondary amine and / or a tertiary amine having a total of 5 to 35 carbon atoms; and as a tenth aspect, the core-shell type metal oxide particle (C) according to any one of the formulas (1) to (3):

[0006]

[0007] (In formula (1), R １ are each 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 are bonded to a silicon atom by a Si—C bond, and R ２ represents an alkoxy group, an acyloxy group, or a halogen group, and a represents an integer of 1 to 3. In formulas (2) and (3), R ３ and R ５ are each 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, and R ４ and R ６each represent 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 particle (C) according to an eighth aspect is a hydrolysate and / or dehydration condensate of at least one silane compound selected from the group consisting of: (a) a silane compound represented by the formula (4) to (6):

[0008]

[0009] (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 represent an integer of 1 to 100; e, g, and i each represent an integer of 1 to 3; Y １ , Y ２ , and Y ３represents 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, wherein the surfactant (B5) is at least one phosphoric acid ester selected from the group consisting of: a thirteenth aspect, the core-shell type metal oxide particle (C) according to the eighth aspect, wherein the surfactant (B5) is an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant; a fourteenth aspect, a core-shell type metal oxide sol comprising the core-shell type metal oxide particle (C) according to any one of the first to thirteenth aspects and a dispersion medium; a fifteenth aspect, the core-shell type metal oxide sol according to the fourteenth aspect, wherein the dispersion medium is water, an alcohol, an ether, an ester, a ketone, an amide, a hydrocarbon, or a combination thereof; a sixteenth aspect, a varnish comprising the core-shell type metal oxide particle (C) or the core-shell type metal oxide sol according to any one of the first to fifteenth aspects, and a thermosetting and / or photosetting resin; and a seventeenth aspect, the varnish according to the sixteenth aspect, wherein the varnish is a varnish for improving light resistance. According to an eighteenth aspect, the varnish according to the sixteenth aspect is a varnish for hard coating. According to a nineteenth aspect, the varnish according to the sixteenth aspect is a varnish for nanoimprinting. According to a twentieth aspect, there is provided a method for producing a core-shell metal oxide sol according to the fourteenth or fifteenth aspect, comprising the following steps (i), (ii) and (iii): step (i): a step (i) of adding a precursor raw material of a metal oxide (A2) containing titanium oxide to a metal oxide sol containing metal oxide particles (A1) as cores and having water as a dispersion medium; step (ii): a step (ii) of heating the sol obtained in step (i), which contains the metal oxide particles (A1) as cores and the precursor raw materials of the metal oxide (A2) containing titanium oxide, thereby coating the surfaces of the metal oxide particles (A1) as cores with the metal oxide (A2) containing titanium oxide; and step (iii): a step (iii) of adding a sol containing a metal oxide (A3) mainly composed of a metal oxide other than titanium oxide and having water as a dispersion medium to the sol obtained in step (ii), and further heating.

[0010] The present invention provides core-shell metal oxide particles that are suitable for use in optical thin films such as hard coats, UV-blocking layers, antireflection films, and diffractive optical elements, and that have excellent light resistance, transparency, and processability, such as for imprinting, as well as a high refractive index, and a method for producing the same, wherein the surface of rutile-type titanium oxide particles that serve as cores and contain at least one oxide 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 primarily composed of a metal oxide other than titanium oxide, and the core-shell metal oxide particles have an average primary particle size of 10 to 20 nm, and a method for producing the same. Because titanium oxide particles have high photoactivity, when they are mixed as a matrix component with various binders or resin components used in high refractive index materials, discoloration and deterioration of the matrix component may occur.

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

[0012] In contrast, by setting the average primary particle diameter of core-shell titanium oxide particles to 10 to 20 nm, when mixed with matrix components such as various binders and resin components, the contact area between the core-shell titanium oxide particles and the matrix component is reduced, thereby suppressing discoloration and deterioration of the matrix component due to the photoactivity of titanium oxide. If such core-shell titanium oxide particles with an average primary particle diameter of 10 to 20 nm contain a large number of coarse particles with a primary particle diameter of more than 20 nm, the varnish obtained by mixing the particles with the matrix component may not achieve sufficient film transparency due to light scattering. In contrast, by building up and coating the surfaces of the core rutile titanium oxide particles with titanium oxide, the number of coarse particles larger than 20 nm can be reduced, thereby achieving sufficient film transparency.

[0013] Preferred embodiments of the present invention will be described below. However, the following embodiments are merely examples for explaining the present invention, and the present invention is not limited to these embodiments. One embodiment of the present invention is core-shell type metal oxide particles (C) having an average primary particle size of 10 to 20 nm, in which the surfaces of core metal oxide particles (A1) are coated with a metal oxide (A2) containing titanium oxide, and the coating is further coated with a metal oxide (A3) mainly composed of a metal oxide other than titanium oxide, and the metal oxide particles (A1) are 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 titanium oxide containing tin oxide, and examples thereof 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 particles can have an average particle size of 5 to 15 nm or 7 to 13 nm as determined by transmission electron microscope observation.

[0015] The titanium oxide-containing metal oxide (A2) that coats the core preferably contains titanium oxide as a main component, and the titanium oxide content may be 50% by mass or more, 50 to 100% by mass, 60 to 100% by mass, 70 to 100% by mass, 80 to 100% by mass, 90 to 100% by mass, or 95 to 100% by mass.

[0016] Examples of the metal oxide (A3) that coats the particles in which the core metal oxide particle (A1) is coated with the titanium oxide-containing metal oxide (A2) include metal oxides such as zirconium oxide, tin oxide, silicon dioxide, zinc oxide, antimony oxide, niobium oxide, tungsten oxide, aluminum oxide, and tantalum oxide, each of which exists alone, and composite metal oxides in which a plurality of the above metal oxides are combined and bonded. Examples of the composite metal oxide 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 mass ratio of silicon dioxide to other metal oxides (silicon dioxide) / (other metal oxides) can be 0.1 to 5.0, 0.5 to 5.0, 1.0 to 5.0, 0.1 to 4.0, or 0.5 to 4.0.

[0017] Examples of the core-shell type metal oxide particles (C) include combinations 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 / titanium oxide / composite metal oxide of tin oxide and silicon dioxide, composite metal oxide particles of titanium oxide, tin oxide and nickel oxide / titanium oxide / composite metal oxide of tin oxide and silicon dioxide, and composite metal oxide particles of titanium oxide, tin oxide and aluminum oxide / titanium oxide / composite metal oxide of tin oxide and silicon dioxide. These core-shell type metal oxide particles (C) have an average primary particle diameter of 10 to 20 nm, 10 to 18 nm, or 12 to 18 nm as determined by observation with a transmission electron microscope. By setting the average primary particle diameter as determined by a transmission electron microscope to 10 to 20 nm, it is possible to achieve both a high refractive index and high light resistance.

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

[0019] The core-shell type metal oxide particles (C) are TiO ２ The titanium oxide content is 60 to 85 mass %, 65 to 85 mass %, or 65 to 80 mass % in terms of the total mass of the titanium oxide.

[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 metal oxide particles in which core metal oxide particles (A1) are coated with a titanium oxide-containing metal oxide (A2) can be obtained by mixing a titania source (D) that generates titanium oxide by hydrolysis and dehydration condensation with an aqueous sol containing rutile titanium oxide particles made of a composite metal oxide of titanium oxide and tin oxide and having an average primary particle size of 5 to 15 nm. Examples of such titania source (D) include titanium tetra-i-propoxide, titanium tetra-n-butoxide, titanium tetra-t-butoxide, titanium tetrachloride, and titanyl sulfate. It is preferable that the titania source (D) has not yet generated titania particles before being mixed 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 metal oxide particles (A1) that serve as the cores can have a pH of 5 to 11.5, preferably 7 to 11.5. The pH of the aqueous sol can be adjusted as necessary with an alkaline component, and examples of the alkaline component that can be used include hydroxides of alkali metals such as lithium, sodium, and potassium, hydroxides of alkaline earth metals such as calcium, magnesium, and strontium, ammonia, alkylamines such as 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 core metal oxide particles (A1) coated with a titanium oxide-containing metal oxide (A2) are further coated with a metal oxide (A3) mainly composed of a metal oxide other than titanium oxide, for example, in the case of a composite metal oxide of tin oxide and silicon dioxide used for coating, sodium stannate or potassium stannate can be used as the alkali stannate, preferably sodium stannate. As the alkali silicate, sodium silicate or potassium silicate can be used.

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

[0025] The alkali stannate and alkali silicate are dissolved in water so that the mass ratio of silicon dioxide to stannic oxide is 0.1 to 5.0. The preferred solid concentration of the aqueous solution is (SnO ２ +SiO ２ ) is 1 to 12 mass %.

[0026] The prepared aqueous solution is subjected to cation exchange resin removal of cations. A hydrogen-type strongly acidic cation exchange resin is preferred, such as Amberlite (trade name) 120B, which can be packed in a column. This cation exchange polymerizes the silicic acid component and the stannic acid component, resulting in a composite metal oxide of stannic oxide and silicon dioxide.

[0027] This composite metal oxide of stannic oxide and silicon dioxide is poor in stability and will gel within a few hours if left standing. Therefore, after the cation exchange, an amine compound is quickly added to stabilize the composite metal oxide, and the silicon dioxide / stannic oxide mass ratio is 0.1 to 5.0 and M / (SnO ２ +SiO ２ It is necessary to prepare an aqueous dispersion of a composite metal oxide (A3) of stannic oxide and silicon dioxide stabilized with an amine compound present in a molar ratio of M / (SnO ２ +SiO２ If the molar ratio of M / (SnO) is less than 0.001, the dispersion stability of the composite metal oxide of stannic oxide and silicon dioxide becomes insufficient, which is not preferable. ２ +SiO ２ If the molar ratio of (SnO) exceeds 0.08, when the particle surfaces of the core-shell type metal oxide particles (C) are further coated with a coating material (B), the coating may be hindered. ２ +SiO ２ ) is 0.1 to 10 mass%, 0.5 to 10 mass%, or 0.5 to 8 mass%.

[0028] Next, an aqueous sol containing particles in which core metal oxide particles (A1) having an average primary particle diameter of 5 to 15 nm are coated with a metal oxide (A2) containing titanium oxide is mixed with an aqueous sol containing particles in which the mass ratio of silicon dioxide to stannic oxide is 0.1 to 5.0 and the M / (SnO ２ +SiO ２) (wherein M represents an amine compound), is mixed with an aqueous dispersion of a composite metal oxide (A3) of stannic oxide and silicon dioxide stabilized with an amine compound in a molar ratio of (A1) to (A2) such that the mass ratio of the composite metal oxide (A3) of stannic oxide and silicon dioxide to the total mass of (A1) and (A2), {(A1) + (A2)} / (A3), is 0.05 to 0.40, thereby obtaining an aqueous sol of core-shell type metal oxide particles (C) in which the metal oxide particles (A1) are coated with the titanium oxide-containing metal oxide (A2), and the coating is further coated with the composite metal oxide (A3) of stannic oxide and silicon dioxide. If the mass ratio is less than 0.05, the particles in which the core metal oxide particles (A1) are coated with the titanium oxide-containing metal oxide (A2) cannot be sufficiently coated with the stannic oxide and silicon dioxide composite metal oxide (A3), 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. The aqueous sol containing the particles in which the core metal oxide particles (A1) are coated with the titanium oxide-containing metal oxide (A2) and the aqueous dispersion of the composite metal oxide (A3) are preferably mixed under stirring.

[0029] In the present invention, the core-shell type metal oxide particles (C) may further be core-shell type metal oxide particles coated with a secondary amine or tertiary amine having a total carbon atom number of 5 to 35. The content of the amine may 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 secondary amine include ethyl n-propylamine, ethylisopropylamine, dipropylamine, diisopropylamine, ethylbutylamine, n-propylbutylamine, dibutylamine, ethylpentylamine, n-propylpentylamine, isopropylpentylamine, dipentylamine, ethyloctylamine, i-propyloctylamine, butyloctylamine, and dioctylamine.

[0031] Examples of the tertiary amine 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 amines and tertiary amines having an alkyl group with a total of 6 to 35 carbon atoms are preferred, and examples thereof include diisopropylamine, tripentylamine, triisopropylamine, dimethyloctylamine, and trioctylamine.

[0033] In the present invention, the core-shell type metal oxide particles (C) may further be 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 are each 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 are bonded to a silicon atom by a Si—C bond, and R ２ represents an alkoxy group, an acyloxy group, or a halogen group, and a represents an integer of 1 to 3. In formulas (2) and (3), R ３ and R ５ are each 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, and R ４ and R ６each 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 is an alkyl group having 1 to 18 carbon atoms, and examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, and a 2,2-dimethyl-n-propyl group. n-hexyl, 1-ethyl-n-propyl, cyclopentyl, 1-methyl-cyclobutyl, 2-methyl-cyclobutyl, 3-methyl-cyclobutyl, 1,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl- n-butyl 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 of alkylene groups include, but are not limited to, 3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl, and 2-ethyl-3-methyl-cyclopropyl groups, as well as hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups. Examples of alkylene groups include those derived from the alkyl groups listed above.

[0036] The aryl group is an aryl group having 6 to 30 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, an anthracene group, and a pyrene group. The alkenyl group is an alkenyl group 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, 3 Examples of alkyl groups include, but are not limited to, 1-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, and 2-methyl-2-pentenyl group.

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

[0038] Examples of the acyloxy group include acyloxy groups having 2 to 10 carbon atoms, such as methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, i-propylcarbonyloxy group, n-butylcarbonyloxy group, i-butylcarbonyloxy group, s-butylcarbonyloxy group, t-butylcarbonyloxy group, n-pentylcarbonyloxy group, 1-methyl-n-butylcarbonyloxy group, 2-methyl-n-butylcarbonyloxy group, 3-methyl-n-butylcarbonyloxy group, 1,1-dimethyl-n-propylcarbonyloxy group, 1,2-dimethyl-n-propylcarbonyloxy group, 2,2-dimethyl-n-propylcarbonyloxy group, 1-ethyl-n-propylcarbonyloxy group, n-hexylcarbonyloxy group, 1-methyl-n-pentylcarbonyloxy group, and 2-methyl-n-pentylcarbonyloxy group, but are not limited to these. Examples of the halogen group include fluorine, chlorine, bromine, and iodine.

[0039] The organic group having a polyether group includes a polyetherpropyl group having an alkoxy group. For example, (CH ３ O) ３ SiC ３ H ６ (OC ２ H ４ ) nOCH ３n can be in the range of 1 to 100, or 1 to 10. Examples of organic groups having an epoxy group include a 2-(3,4-epoxycyclohexyl)ethyl group and a 3-glycidoxypropyl group.

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

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

[0042] An example of an organic group having a ureido group is a 3-ureidopropyl group. An example of an organic group having a cyano group is a 3-cyanopropyl group. The compounds represented by the above formulas (2) and (3) are preferably compounds capable of forming trimethylsilyl groups on the surface of silica particles. Examples of such compounds include the following:

[0043]

[0044] In the above formula, R １２ is an alkoxy group, for example, a methoxy group or an ethoxy group. As the silane compound, a silane compound manufactured by Shin-Etsu Chemical Co., Ltd. can be used. 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, for example, in the range of 20°C to 100°C. The reaction time can be from 0.1 to 6 hours.

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

[0046] Water is required for the hydrolysis of the silane compound, and if the sol is an aqueous solvent, the aqueous solvent can be used. When the aqueous medium is replaced with an organic solvent, the water remaining in the solvent can be used. For example, water present in an amount of 0.01 to 1% by mass can be used. Furthermore, the hydrolysis can be carried out with or without a catalyst.

[0047] When hydrolysis is performed without a catalyst, the surface of the core-shell metal oxide particles (C) is present on the acidic side. When hydrolysis is performed using a catalyst, examples of the hydrolysis catalyst include metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases. Examples of metal chelate compounds as hydrolysis catalysts include triethoxy mono(acetylacetonato)titanium and triethoxy mono(acetylacetonato)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] The organic acid may be 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 threonine. 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 metal salts 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 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, and alkyl, aryl, or arylalkyl esters thereof to form core-shell type metal oxide particles.

[0049] The present invention may further include core-shell type metal oxide particles in which the core-shell type metal oxide particles (C) are coated with at least one phosphate ester (B4) selected from the group consisting of formulas (4) to (6). １ , X ２ , and X ３ each represents an alkylene group having 2 to 20 carbon atoms; f, h, and j each represent an integer of 1 to 100; e, g, and i each represent an integer of 1 to 3; 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, or a (meth)acrylic group. A polyoxyethylene alkyl (C6-20) ether phosphate ester having an alkyl group having 6 to 20 carbon atoms can be used.

[0050] The phosphate ester can preferably be a polyoxyethylene alkyl ether phosphate ester, and the phosphate ester can be one in which the terminal alkyl group (Y1) of the above 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, and amphoteric surfactants to form core-shell type metal oxide particles.

[0051] Examples of anionic surfactants that can be used in the present invention include sodium and potassium salts of fatty acids, alkylbenzenesulfonates, higher alcohol sulfates, polyoxyethylene alkyl ether sulfates, α-sulfofatty acid esters, α-olefinsulfonates, monoalkylphosphates, and alkanesulfonates. For example, alkylbenzenesulfonates include sodium, potassium, and lithium salts, such as sodium C10-C16 alkylbenzenesulfonate, C10-C16 alkylbenzenesulfonic acid, and sodium alkylnaphthalenesulfonate.

[0052] Examples of higher alcohol sulfates include sodium dodecyl sulfate (sodium lauryl sulfate) having 12 carbon atoms, triethanolamine lauryl sulfate, and triethanolammonium lauryl sulfate.

[0053] Polyoxyethylene alkyl ether sulfates include sodium polyoxyethylene styrenated phenyl ether sulfate, ammonium polyoxyethylene styrenated 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 that can be used in the present invention include alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, and amine salts.

[0055] Alkyltrimethylammonium salts are quaternary ammonium salts that have a chloride ion or a bromide ion as a counterion. 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, dicocoalkyldimethylammonium chloride, dihydrogenated tallow alkyldimethylammonium chloride, and dialkyl(C14-18)dimethylammonium chloride.

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

[0057] Examples of amphoteric surfactants that can be used in the present invention include N-alkyl-β-alanine-type alkylamino fatty acid salts, alkylcarboxybetaine-type alkylbetaines, and N,N-dimethyldodecylamine oxide-type alkylamine oxides, such as lauryl betaine, stearyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, and lauryldimethylamine oxide.

[0058] The nonionic surfactant used in the present invention is 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. Examples of 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 styrenated phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzyl phenyl ether.

[0060] 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 dioleate, polypropylene glycol dioleate, etc. 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 ethylene oxide adducts thereof.

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

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

[0065] In the present 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 dispersoid 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 the organic solvent include alcohols having 1 to 10 carbon atoms, such as 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] The ether is a linear or cyclic aliphatic ether having 3 to 30 carbon atoms, such as diethyl ether or tetrahydrofuran. The ester is a linear or cyclic ester having 2 to 30 carbon atoms, such as 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. The ketone is a linear or cyclic aliphatic ketone 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] The amide is an aliphatic amide having 3 to 30 carbon atoms, such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone, etc. The hydrocarbon is a linear or cyclic aliphatic or aromatic hydrocarbon having 6 to 30 carbon atoms, such as hexane, heptane, octane, nonane, decane, benzene, toluene, xylene, etc.

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

[0070] In the present invention, a film-forming composition containing the organic solvent sol and an organic resin is obtained. 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 metal oxide particles (C) and an organic resin. In the case of a thermosetting film-forming composition, the heat curing agent can be added in a range of 0.01 to 50 phr, or 0.01 to 10 phr, relative to the resin containing a functional group such as an epoxy group or a (meth)acryloyl group. For example, the heat curing agent can be added in a ratio of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, relative to the functional group such as an epoxy group or a (meth)acryloyl group. The equivalent of the heat curing agent relative to the curable resin is expressed as the equivalent ratio of the heat curing agent to the functional group.

[0071] Examples of the heat curing agent include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polymercaptans, acid anhydrides, heat radical generators, and heat acid generators. Radical generator-based 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 reduces the density of the cured product and creates pores, resulting in reduced strength and reduced water resistance. Therefore, it is preferable that the curing agent itself is liquid at room temperature and normal pressure. Examples of phenolic resins include phenol novolac resins and cresol novolac resins.

[0073] Examples of amine 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, menthenediamine, isophoronediamine, diaminodicyclohexylmethane, 1,3-diaminomethylcyclohexane, xylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and diethyltoluenediamine. Of these, liquids such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, menthenediamine, isophoronediamine, diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and diethyltoluenediamine can be preferably used.

[0074] The polyamide resin is a polyamide amine produced by condensation of dimer acid and polyamine, and has primary and secondary amines in the molecule.

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

[0076] The polymercaptan is preferably one in which a mercaptan group is present at the end of a polypropylene glycol chain or one in which a mercaptan group is present at the end of a polyethylene glycol chain, and is preferably liquid.

[0077] As the acid anhydride curing agent, the anhydride of the compound having a plurality of carboxyl groups in one molecule is preferred.These acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bistrimellitate, glycerol tristrimellitate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylcyclohexene dicarboxylic anhydride, chlorendic anhydride etc.

[0078] Among these, methyltetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, methylhexahydrophthalic anhydride, and a mixture of hexahydrophthalic anhydride and methylhexahydrophthalic anhydride, which are liquid at room temperature and normal pressure, are preferred. These liquid acid anhydrides have a viscosity of about 10 mPa·s to 1,000 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-methylpropionate)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, with sulfonium salts being preferred. For example, the following compounds can be mentioned.

[0080]

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

[0082] The composition is prepared by mixing a resin, a curing agent, and optionally, a curing aid to obtain a thermosetting varnish. Mixing can be performed in a reaction vessel using a stirring blade or kneader. The resulting thermosetting varnish is a curable coating composition and has an appropriate viscosity for use, for example, as a liquid encapsulant. Liquid thermosetting coating compositions can be prepared to any viscosity and can be used as transparent encapsulants for LEDs and the like by casting, potting, dispenser, printing, or other methods, allowing for partial encapsulation at any desired location. The liquid thermosetting composition can be directly mounted on an LED or the like in its liquid state using the method described above, followed by drying and curing to obtain a cured epoxy resin product.

[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, a photocuring agent (photoradical generator, photoacid generator) can be added in a range of 0.01 to 50 phr, or 0.01 to 10 phr, to a resin containing a functional group such as an epoxy group or a (meth)acryloyl group. For example, the photocuring agent (photoradical generator, photoacid generator) can be added in a ratio of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, to a functional group such as an epoxy group or a (meth)acryloyl group. The equivalent 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 irradiation with light. Examples of the photoradical generator include photoradical polymerization initiators such as 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 the diazo compound 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 the bisimidazole compound 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 the azide compound 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), dicyclopentadienyl 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-pyrrol-1-yl)-phenyl).

[0088] Further examples of the photoradical generator 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-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone.

[0089] These photoradical polymerization agents are available, for example, as Irgacure TPO (component: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) (c1-1-1), manufactured by BASF, Omnirad 819 (component: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) (c1-1-2), manufactured by IGM RESINS, and Irgacure 184 (component: 1-hydroxycyclohexylphenyl ketone) (c1-1-3).

[0090]

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

[0092] The onium salt used as the photoacid generator includes, as an iodonium salt, for example, diphenyliodonium chloride, diphenyliodonium trifluoromethanesulfonate, 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 trifluoromethanesulfonate, bis(p-tert-butylphenyl)iodonium Examples of the iodonium salt include bis(alkylphenyl)iodonium salts such as iodonium tetrafluoroborate, bis(p-tert-butylphenyl)iodonium chloride, bis(p-chlorophenyl)iodonium chloride, bis(p-chlorophenyl)iodonium tetrafluoroborate, and further bis(4-t-butylphenyl)iodonium hexafluorophosphate; alkoxycarbonylalkoxy-trialkylaryl iodonium salts (for example, 4-[(1-ethoxycarbonyl-ethoxy)phenyl]-(2,4,6-trimethylphenyl)-iodonium hexafluorophosphate); and bis(alkoxyaryl)iodonium salts (for example, bis(alkoxyphenyl)iodonium salts such as (4-methoxyphenyl)phenyliodonium hexafluoroantimonate).

[0093] Examples of sulfonium salts include triphenylsulfonium salts such as triphenylsulfonium chloride, triphenylsulfonium bromide, tri(p-methoxyphenyl)sulfonium tetrafluoroborate, tri(p-methoxyphenyl)sulfonium hexafluorophosphonate, tri(p-ethoxyphenyl)sulfonium tetrafluoroborate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium hexafluorophosphate; and 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 the phosphonium salt 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] Further examples include selenium salts such as triphenylselenium hexafluorophosphate, and metallocene complexes such as (η5 or η6-isopropylbenzene)(η5-cyclopentadienyl)iron(II) hexafluorophosphate.

[0096] The following compounds can also be used as photoacid generators.

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] As the photoacid generator, sulfonium salt compounds and iodonium salt compounds are preferred. The anion species thereof is CF ３ SO ３ － , C ４ F ９ SO ３ － , C ８ F １７ SO ３ － , camphorsulfonate anion, tosylate anion, BF ４ － , P.F. ６ － , AsF ６ － and SbF ６ － In particular, anion species such as phosphorus hexafluoride and antimony hexafluoride, which exhibit strong acidity, are preferred.

[0107] The coating composition of the present invention may contain conventional additives as needed. Examples of such additives include pigments, colorants, thickeners, sensitizers, antifoaming agents, coatability improvers, lubricants, stabilizers (antioxidants, heat stabilizers, light stabilizers, etc.), plasticizers, dissolution promoters, fillers, antistatic agents, etc. These additives may be used alone 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 slit coating.

[0109] In the present invention, the varnish (film-forming composition) can be applied to a substrate and cured by light irradiation or thermal curing. Heating can also be performed before or after light irradiation. The thickness of the coating film can be selected from a range of about 0.01 μm to 10 mm depending on the application of the cured product. For example, when used as a photoresist, the thickness can be about 0.05 to 10 μm (particularly 0.1 to 5 μm), when used as a printed wiring board, the thickness can be about 5 μm to 5 mm (particularly 100 μm to 1 mm), and when used as an optical thin film, the thickness can be about 0.1 to 100 μm (particularly 0.1 to 10 μm).

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

[0111] When a photoacid generator is used, the light to be irradiated or exposed may be, for example, gamma rays, X-rays, ultraviolet light, or visible light, and is usually visible light or ultraviolet light, particularly ultraviolet light. The wavelength of the light is, for example, about 150 to 800 nm, preferably about 150 to 600 nm, and more preferably about 150 to 400 nm. The amount of irradiation light varies depending on the thickness of the coating film, but is, for example, about 2 to 20,000 mJ / cm. ２ , preferably 5 to 5000 mJ / cm ２ The light source can be selected depending on the type of light to be exposed, and for example, in the case of ultraviolet light, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a deuterium lamp, a halogen lamp, an LED lamp, or laser light (helium-cadmium laser, excimer laser, etc.) can be used. Such light irradiation causes the curing reaction of the composition to proceed.

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

[0113] Furthermore, when forming a pattern or an image (for example, when producing a printed wiring board, etc.), the coating film formed on the substrate may be subjected to pattern exposure, which may be performed by scanning with laser light or by irradiating with light through a photomask. The non-irradiated areas (unexposed parts) generated by such pattern exposure are developed (or dissolved) with a developer to form a pattern or an image.

[0114] The developer may be an aqueous alkaline solution or an organic solvent, such as an aqueous solution of an alkali metal hydroxide, such as potassium hydroxide, sodium hydroxide, potassium carbonate, or sodium carbonate, an aqueous solution of a quaternary ammonium hydroxide, such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, or choline, or an aqueous solution of an amine, such as ethanolamine, propylamine, or ethylenediamine.

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

[0116] The organic solvent used as the developer may be a common organic solvent, 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. These may be used alone or in combination of two or more. Propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl lactate, etc. are particularly preferred.

[0117] In the present invention, an adhesion promoter can be added for the purpose of improving 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-chloropropyltrimethoxysilane; Examples of adhesion promoters include silanes such as 3-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 urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. These adhesion promoters can be used alone or in combination of two or more. The amount of these adhesion promoters added is typically 18% by mass or less, preferably 0.0008 to 9% by mass, and more preferably 0.04 to 9% by mass, based on the solid content.

[0118] The present invention may contain a sensitizer. Usable sensitizers include anthracene, phenothiazene, perylene, thioxanthone, and benzophenone thioxanthone. Further examples of sensitizing dyes include thiopyrylium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, and pyrylium salt dyes. Anthracene sensitizers are particularly preferred. When used in combination with a cationic curing catalyst (a radiation-sensitive cationic polymerization initiator), they dramatically improve sensitivity and also possess radical polymerization initiation capabilities. In hybrid systems that combine the cationic curing system of the present invention with a radical curing system, the catalyst species can be simplified. Specific anthracene compounds that are effective include dibutoxyanthracene and dipropoxyanthraquinone. The amount of the sensitizer added is 0.01 to 20% by weight, preferably 0.01 to 10% by weight, based on the solid content.

[0119] The composition of the present invention can be photocured or thermally cured 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, commonly used epoxy curing agents (e.g., amines or acid anhydrides) are not used, or even if they are used, the content of these agents is extremely small, which improves 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 photocurable materials using the coating composition of the present invention have characteristics such as fast curing, transparency, and small cure shrinkage, and can be used for coating or bonding electronic components, optical components (anti-reflection coatings), and precision mechanical components.

[0122] The above composition (varnish) can be suitably used as a hard coating agent or a composition for nanoimprints.

[0123] Other applications include the use of this material in bonding mobile phone and camera lenses, optical elements such as light-emitting diodes (LEDs) and semiconductor lasers (LDs), liquid crystal panels, biochips, camera lenses and prisms, magnetic components in hard disks of computers and other devices, pickups in CD and DVD players (the part that captures the optical information reflected from the disc), speaker cones and coils, motor magnets, circuit boards, electronic components, and internal engine components of automobiles and the like.

[0124] As a hard coating material for surface protection of automobile bodies, lamps, electrical appliances, building materials, plastics, etc., 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, ID cards, etc.

[0125] Examples of ink materials for printing on metals such as aluminum and plastics include inks for printing on cards such as credit cards and membership cards, switches on electrical appliances and office equipment, and keyboards, as well as inks for inkjet printers for CDs, DVDs, etc.

[0126] Examples of applications include a technology for curing resins in combination with 3D CAD to create complex three-dimensional objects, application to stereolithography such as the production of models for industrial products, and application to optical fiber coatings, adhesion, optical waveguides, thick-film resists, etc. The film-forming composition of the present invention can also be suitably used as an insulating resin for electronic materials such as antireflection films, semiconductor encapsulation materials, adhesives for electronic materials, diffractive optical element materials, printed wiring board materials, interlayer insulating film materials, and encapsulants for power modules, as well as insulating materials used in high-voltage equipment such as generator coils, transformer coils, and gas-insulated switchgear.

[0127] The present invention will be described in more detail below with reference to Reference Examples, Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples in any way.

[0128] [Total Metal Oxide Concentration] The sol was weighed in a crucible and pre-dried by heating at 110° C. for 30 minutes to remove the solvent, and 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 size by dynamic light scattering (dynamic light scattering particle size)] The sol was diluted with a dispersion solvent, and the particle size was measured using the parameters of the solvent with a dynamic light scattering measuring device (trade name: Zetasizer, manufactured by Malvern Instruments Ltd.) The Z-average particle size was used as the dynamic light scattering particle size.

[0130] [Average Primary Particle Diameter] Particles were photographed using a transmission electron microscope (trade name: JEM-F200, manufactured by JEOL Ltd.), and the particle size distribution of 500 random particles was determined, and the circle-equivalent average primary particle diameter, aspect ratio, and standard deviation σ were calculated.

[0131] [TiO in particles ２ The sol was dried on a hot plate at 110°C and pulverized for 15 minutes using a mortar and pestle to obtain a dry powder. This dry powder was measured using an X-ray fluorescence analyzer (manufactured by Rigaku Corporation, product name Supermini 200) to determine the TiO ２ The mass ratio (mass %) was determined.

[0132] [X-ray diffraction measurement] The sol was dried on a hot plate at 110°C and pulverized for 15 minutes using a mortar and pestle to obtain a dry powder, which was measured using an XRD device (manufactured by Rigaku Corporation, 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 by the following steps i) to iii). i) Preparation of a varnish containing a particle-methanol dispersion 20.00 g of 3-glycidoxypropyltrimethoxysilane (manufactured by Momentive, trade name SILQUEST A-187T) was weighed into a plastic container, to which 18.57 g of methanol and 4.57 g of 0.01 N aqueous hydrochloric acid solution were added, followed by stirring at room temperature for 5 hours. Aluminum 2,4-pentanedionate (Al(acac)) prepared in advance was added. ３ ) in methanol (10% by mass Al(acac) ３6.00 g of 3-glycidoxypropyltrimethoxysilane was added as a curing agent and stirred for 10 minutes to prepare a partial hydrolyzate of 3-glycidoxypropyltrimethoxysilane (concentration: 43% by mass). The partial hydrolyzate of 3-glycidoxypropyltrimethoxysilane, the particle dispersion sol, water, methanol, and 0.25 g of a methanol solution of a leveling agent (DOWSIL trade name L-7604) (10% by mass L-7604) were weighed into a brown bottle so that the total amount was 25.00 g, the final solvent composition was water / total solvent other than water = 1 / 4 by mass, and the particle amounts in the organic solvent dispersion sol were 50 phr, 100 phr, and 150 phr, respectively. The resulting mixture was stirred at room temperature for 30 minutes to prepare a particle-organic solvent dispersion sol-containing varnish (solids concentration: 10.0% by mass, particle amounts: 50 phr, 100 phr, and 150 phr).

[0134] ii) Preparation of particle-containing film The particle-methanol dispersion-containing varnish obtained in i) was irradiated with UV- ３ Approximately 0.5 mL of the solution was dropped onto the treated Si substrate and coated using a spin coater (Mikasa Co., Ltd., product name Opticoat MS-B100) so that the film thickness after coating would be 1.0 μm. The film was then 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 particle-blended films (particle blending amounts: 50 phr, 100 phr, and 150 phr).

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

[0136] [Evaluation of Light Fastness of Dispersion] A dispersion of metal oxide particles at a solid content of 0.5% by mass in a water / methanol = 1 / 1 mass ratio was mixed with a 0.02% by mass solution of a dye (Sunset Yellow) in glycerin at a mass ratio of 1 / 3 to prepare a sample. This was placed in a quartz cell with a length of 1 mm, a width of 1 cm, and a height of 5 cm and sealed. After that, the sample was irradiated with an ultraviolet lamp (manufactured by AS ONE Corporation, trade name SLUV-6) with a wavelength range of I-rays (wavelength 365 nm) selected at an irradiation intensity of 0.4 mW / cm. ２ The sample was irradiated with ultraviolet light at a wavelength of 490 nm (equivalent to a wavelength of 365 nm) for 180 minutes. ０ and A １８０ ) was measured using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, trade name UV-3600), and the fading rate of the dye was calculated using the following formula: ０ ) indicates the absorbance at a wavelength of 490 nm before irradiation with I-rays (wavelength 365 nm), and (A １８０ ) indicates the absorbance at a wavelength of 490 nm after irradiating with I-rays (wavelength 365 nm) for 180 minutes. １８０ ) / (A ０ ) x 100

[0137] Furthermore, the photocatalytic activity of the particles was evaluated based on the following criteria. The lower the rate of fading, the more suppressed the photocatalytic activity of the particles. ◯: Rate of fading is less than 10%. ×: Rate of fading is 10% or more.

[0138] The cured films obtained in the examples and comparative examples were formed and evaluated by the methods described below.

[0139] (1) Film Thickness and Film Refractive Index The reflectance of the cured film formed on the glass substrate was measured using a reflectance measuring device (manufactured by Olympus Corporation, trade name USPM-RU). From the measured reflectance, the film thickness and refractive index of the cured film were calculated using optical simulation.

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

[0141] (3) Light resistance: Using an ultraviolet fluorescent lamp accelerated weathering tester (manufactured by Q-Lab, product name QUV) equipped with a UV-A lamp, 0.89 W / m ２ The cured film formed on the glass substrate was irradiated with ultraviolet light for 6 hours under the condition of d (340 nm). The evaluation criteria are as follows: ０ When the film thickness after the light resistance evaluation is d, the film thickness change rate (%) = (d ０ -d) / d ０ ×100 ◯: The rate of change in film thickness is less than 5%. ×: The rate of change in film thickness is 5% or more.

[0142] (4) Imprintability A varnish containing a dispersion of particles in propylene glycol monomethyl ether (hereinafter, PGME) was spin-coated onto a quartz substrate and heated on a hot plate at 100°C for 2 minutes to produce a film from which the solvent had been removed. The resulting film was irradiated with ultraviolet light using a nanoimprinter (manufactured by Meisho Kiko Co., Ltd., product name NM-0801HB) while a release-treated quartz mold (manufactured by Kyodo International Co., Ltd., product name DTM-2-1) was pressed against it, and the film was cured while transferring a concave-convex pattern. The mold was peeled from the resulting cured film, and the formed pattern was observed with an SEM (manufactured by JEOL Ltd., product name JSM-6010LV). The evaluation criteria were as follows: ○: The pattern was transferred, and the imprintability was good ×: The pattern was not transferred, and the imprintability was poor

[0143] (Production Example 1): Preparation of titanium oxide-stannic oxide composite metal oxide particles (a1) as core particles 171.3 g of a 35 mass % aqueous solution of tetraethylammonium hydroxide was dissolved in 130 g of pure water, and then 5.2 g of metastannic acid (SnO ２ 4.4 g in terms of titanium tetraisopropoxide), 166.7 g (TiO ２ To the resulting sol, 38.5 g of oxalic acid dihydrate (containing 46.8 g of stannic oxide in terms of total sol content) and 38.5 g of oxalic acid dihydrate were added under stirring. The resulting mixed solution was kept at 80°C for 2 hours, and then kept at 95°C for 5 hours while adding pure water to maintain the liquid level constant, thereby preparing a dispersion of titanium oxide-stannic oxide composite metal oxide particles (a1) that would become the cores. The resulting sol had a pH of 4.6 and a total metal oxide concentration (TiO ２ , and SnO ２The average particle size measured by dynamic light scattering was 12 nm, the average primary particle size measured by transmission electron microscopy was 8 nm, and the aspect ratio was 1.8.

[0144] (Production Example 2): Preparation of silicon dioxide-stannic oxide composite metal oxide (b1) to be coated. ２ 77.2 g of sodium stannate (containing 29.8% by mass of sodium stannate in terms of sodium stannate equivalent) was dissolved in 668.8 g of pure water, and then sodium stannate NaSnO ３ ・H ２ O(SnO ２ Into this aqueous solution, 20.9 g of silicon dioxide-stannic oxide composite metal oxide (containing 55.1% by mass in terms of stannic oxide content) was dissolved. The resulting aqueous solution was passed through a column packed with a hydrogen-type cation exchange resin (Amberlite (trade name) IR-120B). Next, 7.2 g of diisopropylamine was added to the resulting aqueous dispersion sol. The resulting aqueous dispersion was an alkaline aqueous dispersion of silicon dioxide-stannic oxide composite metal oxide (b1), with a pH of 8.0 and a total metal oxide concentration (SnO ２ , and SnO ２ ) 2.7% by mass.

[0145] (Production Example 3): Preparation of silicon dioxide (b2) to be coated JIS No. 3 sodium silicate (SiO ２ 77.2 g of silicon dioxide (b1) (containing 29.8% by mass in terms of silicon dioxide equivalent) was dissolved in 689.7 g of pure water. The resulting aqueous solution was passed through a column packed with a hydrogen cation exchange resin (Amberlite (trade name) IR-120B). Next, 4.6 g of diisopropylamine was added to the resulting aqueous dispersion sol. The resulting aqueous dispersion 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 the aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a1) obtained in Production Example 1, 261.7 g of a 35 mass % aqueous solution of tetraethylammonium hydroxide, 255 g of titanium tetraisopropoxide (TiO ２To the resulting mixture, 58.8 g of oxalic acid dihydrate (containing 71.6 g of titanium dioxide equivalent to 100% ammonium hydroxide) and 58.8 g of oxalic acid dihydrate were added under stirring. The mixed solution was maintained at 80°C for 2 hours, and then maintained at 95°C for 5 hours while adding pure water to maintain a constant liquid level. The mixed solution was then placed in a glass-lined autoclave and subjected to hydrothermal treatment at 140°C for 5 hours to grow particles. The resulting sol was desalted and washed by ultrafiltration, and 2.4 g of 35% tetraethylammonium hydroxide was added. The resulting sol was passed through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Corporation) to obtain a sol. The resulting sol was an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a2) coated with titanium oxide, and had a pH of 12.1 and a total metal oxide concentration (TiO ２ , and SnO ２ The sol was dried at 110°C and the powder was subjected to X-ray diffraction measurement, which confirmed that the powder was a rutile crystal.

[0147] Zirconium oxychloride 35.1 g (ZrO ２The resulting aqueous solution (containing 7.0 g of silicon dioxide equivalent to 100%) was diluted with 475 g of pure water to prepare 510.1 g of an aqueous zirconium oxychloride solution, to which 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. This was then heated at 95°C for 5 hours to cause hydrolysis, yielding an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles in which a thin film layer of zirconium oxide had been further formed on the titanium oxide-coated surfaces. 2073.0 g of the resulting aqueous dispersion was added under stirring to 565.3 g of the aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the mixture 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 then passed through a column packed with a cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Corporation). 3.1 g of tri-n-pentylamine was added to the obtained aqueous dispersion, which was then concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles (c1) coated with silicon dioxide-stannic oxide composite metal oxide. The dispersion medium of the obtained aqueous dispersion 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 5.2, a total metal oxide content of TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The concentration of the TiO particles was 30.0 mass % and the viscosity was 5.0 mPa s. ２ The mass ratio was 70%, the average primary particle size measured by a transmission electron microscope was 15 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.2, and the dispersion light resistance was evaluated as good.

[0148] Example 2 To 471 g of the aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a1) obtained in Production Example 1, 203.5 g of a 35 mass % aqueous solution of tetraethylammonium hydroxide and 198.4 g of titanium tetraisopropoxide (TiO ２To the resulting sol, 45.8 g of oxalic acid dihydrate (containing 55.8 g of titanium dioxide equivalent to 55.8 g of stannic oxide) and 45.8 g of oxalic acid dihydrate were added under stirring. The mixed solution was maintained at 80°C for 2 hours, and then maintained at 95°C for 5 hours while adding pure water to maintain a constant liquid level. The mixed solution was then placed in a glass-lined autoclave and subjected to hydrothermal treatment at 140°C for 5 hours to grow particles. The resulting sol was desalted and washed by ultrafiltration, and 2.5 g of 35% tetraethylammonium hydroxide was added. The resulting sol was passed through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Corporation) to obtain a sol. The resulting sol was an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles coated with titanium oxide, and had a pH of 12.0 and a total metal oxide concentration (TiO ２ , and SnO ２ The sol was dried at 110°C and the powder was subjected to X-ray diffraction measurement, which confirmed that the powder was a rutile crystal.

[0149] Zirconium oxychloride 36.9 g (ZrO ２The resulting aqueous solution (containing 7.4 g of silicon dioxide, calculated as 7.4 g of silicon dioxide) was diluted with 876.4 g of pure water to prepare 913.3 g of zirconium oxychloride solution, to which 1,000 g of an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles coated with titanium oxide was added under stirring. The resulting aqueous dispersion was then heated at 95°C for 5 hours to cause hydrolysis, 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 surfaces. 1,913 g of the resulting aqueous dispersion was added under stirring to 619.5 g of the aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the mixture 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 then passed through a column packed with a cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Corporation). 1.7 g of tri-n-pentylamine was added to the obtained aqueous dispersion, which was then concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles (c2) coated with silicon dioxide-stannic oxide composite metal oxide. The dispersion medium of the obtained aqueous dispersion 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 5.0, a total metal oxide content of TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The concentration of the TiO particles was 30.1% by mass, and the viscosity was 5.0 mPa·s. ２ The mass ratio was 65 mass %, the average primary particle size measured by a transmission electron microscope was 13 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.12, and the dispersion light resistance was evaluated as good.

[0150] Example 3 1968.5 g of the aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles prepared in Example 1, in which a thin film layer of zirconium oxide was further formed on the titanium oxide-coated surface, was added with stirring to 648.1 g of the aqueous dispersion of alkaline silicon dioxide (b2) prepared in Production Example 3, and the mixture 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 then 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 mixture was concentrated by ultrafiltration to a total metal oxide concentration of 20% by mass, to obtain an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles (c4) coated with silicon dioxide. Next, 338 g of methanol and 6.7 g of 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name KBM-503) were added, and the mixture was heated at 60°C for 5 hours to modify the particle surfaces. The dispersion medium of the obtained aqueous dispersion was replaced with methanol in a rotary evaporator to obtain a methanol dispersion of core-shell type metal oxide particles. This methanol dispersion had a pH of 4.8 and a total metal oxide (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The concentration of the TiO particles was 30.0 mass % and the viscosity was 5.1 mPa s. ２ The mass ratio was 64 mass %, the average primary particle diameter measured by a transmission electron microscope was 14 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.10, and the dispersion light resistance was evaluated as good.

[0151] Example 4 To 1428.5 g of the aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a2) coated with titanium oxide obtained in Production Example 1, 1428.5 g of methanol and 41.1 g of ethyl orthosilicate (SiO ２To the mixture was added a solution of titanium dioxide-stannic oxide composite metal oxide particles (c4) coated with silicon dioxide under stirring. The mixture was heated and stirred at 50°C for 24 hours to obtain an aqueous dispersion of titanium dioxide-stannic oxide composite metal oxide particles (c4) coated with silicon dioxide. 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 mixture was heated at 60°C for 5 hours to modify the particle surfaces. Thereafter, 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 and a total metal oxide (TiO ２ , SnO ２ , and SiO ２ The particle concentration was 29.5% by mass, and the viscosity was 5.3 mPa s. The TiO2 mass ratio in the particles was 79% by mass, the average primary particle size measured by a transmission electron microscope was 13 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.19, and the dispersion light resistance was evaluated as good.

[0152] Example 5 3.0 g of 3-methacryloxypropyltrimethoxysilane was added to 100.0 g of the methanol dispersion of (c1) obtained in Example 1, and the mixture was heated at 60°C for 5 hours to modify the particle surfaces. The obtained methanol dispersion had a pH of 5.4 and a total metal oxide (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The concentration of the TiO particles was 30.2% by mass, and the viscosity was 5.1 mPa s. ２ The mass ratio was 70 mass %, the average primary particle size measured by a transmission electron microscope was 15 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.2, and the dispersion light resistance was evaluated as good.

[0153] Example 6 To 100.0 g of the methanol dispersion of (c1) obtained in Example 1, 3.0 g of phenyltrimethoxysilane (trade name: KBM-103, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was heated at 60°C for 5 hours to modify the particle surfaces. The obtained methanol dispersion had a pH of 5.4 and a total metal oxide (TiO ２ , ZrO ２ , SnO２ , and SiO ２ The concentration of the TiO particles was 30.1% by mass, and the viscosity was 5.0 mPa·s. ２ The mass ratio was 70 mass %, the average primary particle size measured by a transmission electron microscope was 15 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.2, and the dispersion light resistance was evaluated as good.

[0154] Example 7 To 100.0 g of the methanol dispersion of (c1) obtained in Example 1, 3.0 g of 2-(allyloxymethyl)acrylate (trimethoxysilyl)propyl (manufactured by Shin-Etsu Chemical Co., Ltd., product name X-12-1333A) was added, and the mixture was heated at 60°C for 5 hours to modify the particle surfaces. The obtained methanol dispersion had a pH of 5.4 and a total metal oxide (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The concentration of the TiO particles was 30.2% by mass, and the viscosity was 5.1 mPa s. ２ The mass ratio was 70 mass %, the average primary particle size measured by a transmission electron microscope was 15 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.2, and the dispersion light resistance was evaluated as good.

[0155] Comparative Example 1 797.9 g of the aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a1) obtained in Production Example 1 was placed in a glass-lined autoclave vessel and subjected to hydrothermal treatment 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 passed through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Corporation) to obtain a sol. The obtained sol was an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles without a titanium oxide coating, and had a pH of 11.9 and a total metal oxide concentration (TiO ２ , and SnO ２ The sol was dried at 110°C and the powder was subjected to X-ray diffraction measurement, which confirmed that the powder was a rutile crystal.

[0156] Zirconium oxychloride 75.1 g (ZrO ２ The resulting aqueous solution (containing 15 g of silicon dioxide-stannic oxide composite metal oxide) was diluted with 1,425.0 g of pure water to prepare 1,500.0 g of a zirconium oxychloride solution, to which 1,499.7 g of an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles was added under stirring. The resulting aqueous dispersion was then heated at 95°C for 5 hours to cause hydrolysis, yielding an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles on which a thin film layer of zirconium oxide had been formed. 2,978.4 g of the resulting aqueous dispersion was added under stirring to 1,333.2 g of the aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the mixture 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 then passed through a column packed with a cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Corporation). 5.4 g of tri-n-pentylamine was added to the obtained aqueous dispersion, and the mixture was concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles (c6) coated with silicon dioxide-stannic oxide composite metal oxide. The dispersion medium of the obtained aqueous dispersion 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 5.5, a total metal oxide content of TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The concentration of the TiO particles was 30.5% by mass and the viscosity was 4.8 mPa s. ２ The mass ratio was 55 mass %, the average primary particle size measured by a transmission electron microscope was 11 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, the refractive index was 2.04, and the dispersion light resistance was evaluated as good.

[0157] Comparative Example 2 A sol was prepared in the same manner as in Production Example 1, except that the amount of the tetraethylammonium hydroxide aqueous solution was changed to 221.8 g. The obtained sol had a pH of 5.3 and a total metal oxide concentration (TiO ２ , and SnO ２The sol contained 10.2 mass% of titanium oxide and stannic oxide composite metal oxide particles, the average particle size determined by dynamic light scattering was 16 nm, and the aspect ratio of the primary particles determined by observation with a transmission electron microscope was 3.0. Deformed particles that had grown only in the long axis direction were obtained. 735.3 g of this sol was placed in a glass-lined autoclave vessel and subjected to hydrothermal treatment 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 passed through a column packed with 500 ml of ion exchange resin (Amberlite (trade name) IRA-410, manufactured by Organo Corporation) to obtain a sol. The obtained sol was an aqueous dispersion of deformed titanium oxide-stannic oxide composite metal oxide particles without a titanium oxide coating, and had a pH of 12.2 and a total metal oxide concentration (TiO ２ , and SnO ２ The sol was dried at 110°C and the powder was subjected to X-ray diffraction measurement, which confirmed that the powder was a rutile crystal.

[0158] Zirconium oxychloride 75.1 g (ZrO ２The resulting aqueous solution (containing 15 g of silicon dioxide-stannic oxide composite metal oxide) was diluted with 1,425.0 g of pure water to prepare 1,500.0 g of a zirconium oxychloride solution, to which 1,562.5 g of an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles was added under stirring. The resulting aqueous dispersion was then heated at 95°C for 5 hours to cause hydrolysis, yielding an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles on which a thin film layer of zirconium oxide had been formed. 3,058.6 g of the resulting aqueous dispersion was added under stirring to 250.0 g of the aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, and the mixture 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 then passed through a column packed with a cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Corporation). 2.6 g of tri-n-pentylamine was added to the obtained aqueous dispersion, which was then concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannic oxide-zirconium oxide composite metal oxide particles (c7) coated with silicon dioxide-stannic oxide composite metal oxide. The dispersion medium of the obtained aqueous dispersion 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 5.8, a total metal oxide content of TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The particle concentration was 30.7% by mass, the viscosity was 6.5 mPa s, the TiO2 mass ratio in the particles was 70% by mass, the average primary particle diameter measured by a transmission electron microscope was 15 nm, the aspect ratio was 3.0, the standard deviation was σ3 nm, the refractive index was 2.2, and the dispersion light resistance was evaluated as good.

[0159] Comparative Example 3 To 184.4 g of the aqueous dispersion of alkaline silicon dioxide-stannic oxide composite metal oxide (b1) prepared in Production Example 2, 1500.0 g of the aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a2) coated with titanium oxide obtained in Example 1 was added under stirring, and the mixture was heated at 95°C for 3 hours, and then passed through a column packed with a cation exchange resin (Amberlite (trade name) IR-120B, manufactured by Organo Corporation). 1.6 g of tri-n-pentylamine was added to the obtained aqueous dispersion, and the mixture was concentrated by ultrafiltration to obtain an aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (c8) coated with silicon dioxide-stannic oxide composite metal oxide. The dispersion medium of the obtained aqueous dispersion 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 5.2, a total metal oxide content of 1.0% (TiO ２ , SnO ２ , and SiO ２ The concentration of the TiO particles was 30.4% by mass and the viscosity was 4.5 mPa·s. ２ The mass ratio was 89 mass%, the average primary particle diameter measured by a transmission electron microscope was 13 nm, the aspect ratio was 1.8, the standard deviation σ was 2 nm, and the refractive index was 2.3. The coating of metal oxides other than titanium oxide was insufficient, so the dispersion light resistance was rated as ×.

[0160] Comparative Example 4 0.2 g of tri-n-pentylamine was added to 200.0 g of the aqueous dispersion of titanium oxide-stannic oxide composite metal oxide particles (a2) coated with titanium oxide obtained in Example 1, and the mixture was concentrated by ultrafiltration. The dispersion medium of this aqueous dispersion was then replaced with methanol in a rotary evaporator to obtain a methanol dispersion of metal oxide particles. This methanol dispersion had a pH of 11.7 and a total metal oxide (TiO ２ , and SnO ２ The concentration of the TiO particles was 25.1% by mass and the viscosity was 6.3 mPa s. ２ The mass ratio was 98 mass%, the average primary particle diameter measured by a transmission electron microscope was 12 nm, the aspect ratio was 1.8, the standard deviation was σ2 nm, and the refractive index was 2.4. Since the particles were not coated with a metal oxide other than titanium oxide, the light resistance of the dispersion was evaluated as ×.

[0161] (Example 8) The dispersion medium of the methanol dispersion of the particles (c1) obtained in Example 1 was replaced with PGME using a rotary evaporator to obtain a PGME dispersion of the particles (c1). This PGME dispersion contains a total metal oxide (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ etc.) concentration was 20.5% by mass, and the average particle size measured by dynamic light scattering (DLS) (dynamic light scattering particle size) was 28 nm.

[0162] (Film Evaluation) A cured film was prepared using the obtained PGME dispersion by the following procedure. 0.75 g of a mixture of dipentaerythritol hexaacrylate and pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name KAYARAD DPHA) as a resin binder and 1.8 g of PGME were added to a brown bottle equipped with a magnetic stirrer, and 10.98 g of a PGME dispersion of particles (c1) (particle addition amount: 300 phr) was added while stirring. 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 (L-7001 concentration 10.0% by mass) of a polyether-modified silicone surface modifier (manufactured by Dow-Toray Co., Ltd., trade name DOWSIL (trade name) L-7001) were added, and the mixture was stirred for 0.5 hours to prepare a varnish. Glass substrates were prepared, and varnish was applied to them by spin coating. After the solvent was evaporated at 100°C for 2 minutes, the substrate was exposed to a cumulative light intensity of 1000 mJ / cm ２ The resulting cured film had a thickness of 1.0 μm, a refractive index of 1.85, a haze of 0.18%, and a light resistance of "○". The same varnish was also used to evaluate its imprintability, which was also evaluated as "○".

[0163] (Example 9) A PGME dispersion of particles (c2) was prepared using the methanol dispersion of particles (c2) obtained in Example 2 in the same manner as in Example 9. This PGME dispersion contained a total metal oxide (TiO ２ , ZrO ２ , SnO ２ , and SiO ２The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 23 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used in film evaluation. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.82, a haze of 0.15%, and a light resistance of "○". Furthermore, when the same varnish was used to evaluate imprintability, it was rated "○".

[0164] (Example 10) A PGME dispersion of particles (c3) was prepared in the same manner as in Example 9, except that the methanol dispersion of particles (c3) surface-modified with 3-methacryloxypropyltrimethoxysilane obtained in Example 3 was used instead of the methanol dispersion of particles (c1) obtained in Example 1. This PGME dispersion was prepared by dissolving all metal oxides (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 20 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used in film evaluation. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.81, a haze of 0.16%, and a light resistance of "○". Furthermore, when the same varnish was used to evaluate imprintability, it was rated "○".

[0165] (Example 11) A PGME dispersion of particles (c4) was prepared in the same manner as in Example 9, except that the methanol dispersion of particles (c4) surface-modified with 3-methacryloxypropyltrimethoxysilane obtained in Example 4 was used instead of the methanol dispersion of particles (c1) obtained in Example 1. This PGME dispersion was prepared by dissolving all metal oxides (TiO ２ , ZrO ２ , SnO ２ , and SiO ２The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 24 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used in film evaluation. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.85, a haze of 0.14%, and a light resistance of "○". Furthermore, when the same varnish was used to evaluate imprintability, it was rated "○".

[0166] (Example 12) A PGME dispersion of particles (c1) was prepared in the same manner as in Example 9, except that the methanol dispersion of particles (c1) surface-modified with 3-methacryloxypropyltrimethoxysilane obtained in Example 5 was used instead of the methanol dispersion of particles (c1) obtained in Example 1. This PGME dispersion was prepared by dissolving all metal oxides (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 18 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used in film evaluation. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.82, a haze of 0.15%, and a light resistance of "○". Furthermore, when the same varnish was used to evaluate imprintability, it was rated "○".

[0167] (Example 13) A PGME dispersion of particles (c1) was prepared in the same manner as in Example 9, except that the methanol dispersion of particles (c1) surface-modified with phenyltrimethoxysilane obtained in Example 6 was used instead of the methanol dispersion of particles (c1) obtained in Example 1. This PGME dispersion was prepared by dissolving all metal oxides (TiO ２ , ZrO ２ , SnO ２ , and SiO ２The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 17 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 8, except that this PGME dispersion was used in film evaluation. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.83, a haze of 0.21%, and a light resistance of "○". Furthermore, when the same varnish was used to evaluate imprintability, it was rated "○".

[0168] (Example 14) A PGME dispersion of particles (c1) was prepared in the same manner as in Example 9, except that the methanol dispersion of particles (c1) surface-modified with 2-(allyloxymethyl)(trimethoxysilyl)propyl acrylate obtained in Example 7 was used instead of the methanol dispersion of particles (c1) obtained in Example 1. This PGME dispersion was prepared by the same procedure as in Example 9, except that the total metal oxide (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 15 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used in film evaluation. The obtained cured film had a thickness of 1.0 μm, a refractive index of 1.82, a haze of 0.10%, and a light resistance of "○". Furthermore, when the same varnish was used to evaluate imprintability, it was rated "○".

[0169] (Comparative Example 5) A PGME dispersion of particles (c6) was prepared in the same manner as in Example 9, except that the methanol dispersion of particles (c6) obtained in Comparative Example 1 was used instead of the methanol dispersion of particles (c1) obtained in Example 1. This PGME dispersion was prepared by dissolving all metal oxides (TiO ２ , ZrO ２ , SnO ２ , and SiO ２The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 17 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used in film evaluation. The obtained cured film had a thickness of 1.1 μm, a refractive index of 1.79, a haze of 0.14%, and a light resistance of "○". Furthermore, when the same varnish was used to evaluate imprintability, it was rated "○".

[0170] (Comparative Example 6) A PGME dispersion of particles (c7) was prepared in the same manner as in Example 9, except that the methanol dispersion of particles (c7) obtained in Comparative Example 2 was used instead of the methanol dispersion of particles (c1) obtained in Example 1. This PGME dispersion was prepared by dissolving all metal oxides (TiO ２ , ZrO ２ , SnO ２ , and SiO ２ The PGME dispersion had a concentration of 20.5% by mass, and an average particle size (dynamic light scattering particle size) of 43 nm as measured by dynamic light scattering (DLS). Furthermore, a cured film was prepared in the same manner as in Example 9, except that this PGME dispersion was used in film evaluation. The resulting cured film had a high haze of 0.8%, and a transparent film was not obtained, so the thickness and refractive index could not be calculated by optical simulation based on reflectance.

[0171] The core-shell metal oxide particles obtained in Examples 1 to 7 had an average primary particle size of 13 to 15 nm, a standard deviation σ of 2 nm, an aspect ratio of 1.8, a refractive index of 2.10 to 2.29, and a dispersion light resistance of 0. The cured films obtained in Examples 8 to 14 had a refractive index of 1.81 to 1.86, a haze of 0.10 to 0.25, a light resistance of "○", and an imprintability of "○", and were therefore excellent in refractive index, transparency, and light resistance.

[0172] The core-shell metal oxide particles obtained in Comparative Example 1 had a refractive index of 2.04, while the cured film of Comparative Example 5 had a refractive index of 1.79, indicating that the refractive index was insufficient. The core-shell metal oxide particles obtained in Comparative Example 2 had an aspect ratio of 3.0, while the cured film of Comparative Example 6 had a haze of 0.8%, indicating that the transparency was insufficient. The core-shell metal oxide particles obtained in Comparative Examples 3 and 4 had a dispersion light resistance of ×, indicating that the light resistance was insufficient. From the above results, it was revealed that the core-shell metal oxide particles of the present invention can adjust the primary particle size while maintaining the aspect ratio by coating the surface of the core metal oxide particles with titanium oxide and then coating the coating with a metal oxide mainly composed of a metal oxide other than titanium oxide, and have excellent light resistance, transparency, and processability such as imprinting, as well as a high refractive index. It was also revealed that compositions incorporating the particles have excellent optical properties.

[0173] The core-shell type metal oxide particles of the present invention are suitable for use as optical thin films such as hard coats, ultraviolet cut layers, anti-reflection films, and diffractive optical elements when combined with a thermosetting or photocurable resin.

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 equivalent circle particle diameter of the particles when observed with a transmission electron microscope of less than 3 nm.

2. The core-shell type metal oxide particles (C) according to claim 1, wherein the surface of the 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) containing a metal oxide other than titanium oxide as a main component, and the metal oxide particle (A1) is a rutile type titanium oxide containing at least one oxide 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 a composite oxide of two or more metal oxides.

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

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

7.

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

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

8. The core-shell type metal oxide particles (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), and surfactants (B5).

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

10. The silane compound (B2) is represented by the formula (1) to (3): (In formula (1), R １ each represents 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; R ２ Each represents an alkoxy group, an acyloxy group, or a halogen group, a represents an integer of 1 to 3, and in formula (2) and formula (3), R ３ and R ５ are each 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.

11. The core-shell metal oxide particles (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 represented by the formula (4) to (6): (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 represent an integer of 1 to 100; e, g, and i each represent an integer of 1 to 3; 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.

13. The core-shell type metal oxide particles (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 the core-shell type metal oxide particles (C) according to claim 1 and a dispersion medium.

15. The core-shell metal oxide sol according to claim 14, wherein the dispersion medium is selected from the group consisting of water, alcohol, ether, ester, ketone, amide, hydrocarbon, and combinations thereof.

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

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

20. A method for producing a core-shell metal oxide sol according to claim 14 or 15, comprising the following steps (i), (ii) and (iii): step (i): a step of adding a precursor raw material of a metal oxide (A2) containing titanium oxide to a metal oxide sol containing metal oxide particles (A1) as cores and having water as a dispersion medium; step (ii): a step of heating the sol containing the metal oxide particles (A1) as cores and the precursor raw materials of the titanium oxide (A2) obtained in step (i) to coat the surfaces of the metal oxide particles (A1) as cores with the metal oxide (A2) containing titanium oxide; step (iii): a step of adding a sol containing a metal oxide (A3) mainly composed of a metal oxide other than titanium oxide and having water as a dispersion medium to the sol obtained in step (ii), and further heating the resulting mixture (iii).

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