Organic solvent sol of amine-containing hollow silica particles, and method for producing same

Abstract

[Problem] To provide: an organic solvent sol of hollow silica particles, in which the sol contains an amine, the hollow silica particles have a specific surface charge, exhibit high dispersibility in a resin, and have a space inside an outer shell; a method for producing same; and a film-forming composition. [Solution] Provided is an organic solvent sol of hollow silica particles, in which the sol contains an amine and the hollow silica particles have a space inside an outer shell. The amine is at least one type of amine selected from among a primary amine, secondary amine and tertiary amine having a total of 1-10 carbon atoms. The water solubility of the amine is 80 g / L or more. The content of the amine is 0.001-10 mass% relative to SiO2 in the hollow silica particles. The average particle diameter of the hollow silica particles, as measured using a dynamic light-scattering method, is 20-150 nm. The surface charge amount is 5-250 μeq / g, as calculated per 1 g of SiO2 in the hollow silica particles. The organic solvent is an alcohol, ketone, ether or ester having 1-10 carbon atoms. Also provided is a film-forming composition that contains the organic solvent sol of hollow silica particles and an organic resin.

Description

Organic solvent sol of amine-containing hollow silica particles and method for producing the same

[0001] The present invention relates to a sol containing an amine and hollow silica particles dispersed in an organic solvent, a method for producing the sol, and a film-forming composition containing the sol.

[0002] Hollow silica particles have a silica shell and a space inside the shell, and because of these characteristics, they have properties such as a low refractive index, low thermal conductivity (thermal insulation), and electrical insulation. Hollow silica particles consist of a core that corresponds to the hollow part and a shell that forms the outside of the core. An aqueous dispersion of hollow silica particles can be obtained by forming a silica layer on the outside of the core in an aqueous medium and then removing the core. For example, hollow silica particles with a surface charge of 5 to 20 μeq / g-SiO ２ A composition for forming a transparent coating film containing hollow silica particles of formula (I) and a binder component has been disclosed (see Patent Document 1). Also, hollow silica particles whose surfaces are coated with a silane compound and whose thermal weight loss at 200°C to 500°C is 1% by mass or more have been disclosed (see Patent Document 2).

[0003] International Publication No. 2007-060884 Japanese Patent Application Laid-Open No. 2013-014506

[0004] The present invention provides an organic solvent sol of hollow silica particles containing an amine in the sol and having spaces inside the outer shell, a method for producing the sol, and a film-forming composition containing the sol.

[0005] The present invention provides, as a first aspect, an organic solvent sol of hollow silica particles containing an amine in the sol and having spaces inside the outer shell; as a second aspect, the sol according to the first aspect, in which the amine is at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines having 1 to 10 carbon atoms; as a third aspect, the sol according to the first or second aspect, in which the amine is a water-soluble amine having a water solubility of 80 g / L or more; and as a fourth aspect, the sol according to the first aspect, in which the content of the amine is a water-soluble amine having a water solubility of 80 g / L or more; ２As a fifth aspect, the sol according to any one of the first to fourth aspects, wherein the average particle size of the hollow silica particles measured by a dynamic light scattering method is 20 to 150 nm; as a sixth aspect, the sol according to any one of the first to fourth aspects, wherein the SiO content of the hollow silica particles is 0.001 to 10 mass % relative to the total mass of the sol; ２ the sol according to any one of the first to fifth aspects, in which the surface charge amount calculated per 1 g of the sol is 5 to 250 μeq / g; as a seventh aspect, the sol according to any one of the first to sixth aspects, in which the organic solvent is an alcohol, ketone, ether, or ester having 1 to 10 carbon atoms; as an eighth aspect, the hollow silica particles further comprise a compound represented by formula (1), formula (2), and formula (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 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 via a Si—C bond; R ２ each represents an alkoxy group, an acyloxy group, or a halogen group, and a is an integer of 1 to 3; ３ and R ５ represents an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms, and is bonded to a silicon atom via a Si—C bond; 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. As a ninth aspect, a film-forming composition comprising the sol according to any one of the first to eighth aspects and an organic resin; As a tenth aspect, a film obtained from the film-forming composition according to the ninth aspect, which has a visible light transmittance of 80% or more; As an eleventh aspect, a film obtained from the film-forming composition according to the ninth aspect, which has a visible light transmittance of 80% or more; and As a eleventh aspect, a film obtained from the film-forming composition according to the ninth aspect, which has a visible light transmittance of 80% or more, the film being obtained from the film-forming composition according to the eleventh aspect, which comprises the following steps (A) to (C): step (A): a step of preparing a hollow silica aqueous sol; step (B): adding at least one amine having a water solubility of 80 g / L or more and selected from the group consisting of primary amines, secondary amines, and tertiary amines having 1 to 10 carbon atoms to the hollow silica aqueous sol of step (A), to form a film having a visible light transmittance of 80% or more, which is obtained by dissolving the SiO ２a step of adding 0.001 to 10 mass % of the aqueous sol of hollow silica particles obtained in the step (B) at a ratio of 0.001 to 10 mass % to the total mass of the aqueous sol of hollow silica particles; the method for producing a sol according to any one of the first to eighth aspects, comprising: a step (C): performing solvent substitution on the aqueous medium of the aqueous sol of hollow silica particles obtained in the step (B) with an alcohol, ketone, ether, or ester having 1 to 10 carbon atoms; as a twelfth aspect, the method for producing a sol according to the eleventh aspect, comprising: a step (D) of further adding at least one silane compound selected from the group consisting of silane compounds represented by formula (1), formula (2), and formula (3) above, and heating after completion of the step (C); and as a thirteenth aspect, the method for producing a sol according to the eleventh or twelfth aspect, in which the step (C) is a step of performing solvent substitution on the aqueous medium with an alcohol having 1 to 10 carbon atoms, and then performing solvent substitution with a ketone, ether, or ester having 1 to 10 carbon atoms. As a fourteenth aspect, there is provided the method for producing a sol according to the twelfth aspect, in which the step (C) is a step of subjecting the aqueous medium to solvent substitution with an alcohol having 1 to 10 carbon atoms, and the step (D) is a step of adding at least one silane compound selected from the group consisting of silane compounds represented by formula (1), formula (2), and formula (3), heating, and then subjecting the alcohol solvent to solvent substitution with a ketone, ether, or ester having 1 to 10 carbon atoms; and as a fifteenth aspect, there is provided a method for adjusting the surface charge of hollow silica particles, using the production method according to any one of the eleventh to fourteenth aspects.

[0006] The present invention relates to an organic solvent sol of hollow silica particles containing an amine and having a void space inside the outer shell. It is known that hollow silica particles dispersed in an organic solvent possess a surface charge. The surface charge of the hollow silica particles themselves, or when the hollow silica particle organic solvent sol is mixed with an organic resin binder, can significantly affect stability and dispersibility. For example, when hollow silica particles are dispersed in a highly polar solvent or resin binder, stable dispersibility can be achieved if the surface charge of the hollow silica particles is within a specific range. The need for stable dispersibility is due to the fact that, when forming a coating, it is advantageous for the hollow silica particles to be uniformly present in the cured coating and not localized, thereby achieving a uniform effect throughout the entire film. This delocalization of hollow silica particles in the cured coating ensures uniform performance throughout the film. This effect is advantageous when the film is used for optical antireflection, as it maintains uniform performance throughout the film.

[0007] The surface charge amount of hollow silica particles in a dispersion medium is due to silanol groups on the surface of the silica particles, and it has been found that the surface charge amount can be arbitrarily adjusted within a specific range by adding an amine. The present invention relates to an organic solvent sol of hollow silica particles that contain an amine in the sol and have a space inside the outer shell, a method for producing such an organic solvent sol, and a coating-forming composition using such an organic solvent sol.

[0008] The present invention relates to an organic solvent sol of hollow silica particles containing an amine in the sol and having a space inside the outer shell (hereinafter also referred to as hollow silica organic solvent sol).

[0009] Hollow silica particles have a silica outer shell and a space inside the shell. Hollow silica particles are obtained by forming a silica-based outer shell on the surface of a portion corresponding to the core, known as a template, in a dispersion medium, and then removing the portion corresponding to the core. The aqueous hollow silica sol (hollow silica aqueous sol) obtained in this manner can be subjected to solvent substitution with an alcoholic organic solvent after adding an amine. The alcoholic solvent is preferably an alcohol having 1 to 5 carbon atoms, which may have an ether bond, such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, propylene glycol monomethyl ether, or propylene glycol monoethyl ether. Subsequently, if desired, the hollow silica particles can be coated with a silane compound, and the solvent can then be further substituted with another organic solvent.

[0010] In the present invention, organic solvents include alcohols, ketones, ethers, and esters having 1 to 10 carbon atoms.

[0011] Alcohols having 1 to 10 carbon atoms are aliphatic alcohols, including primary alcohols, secondary alcohols, and tertiary alcohols. Polyhydric alcohols can also be used, including dihydric alcohols and trihydric alcohols. Examples of monohydric primary alcohols include methanol, ethanol, 1-propanol, 1-butanol, and 1-hexanol. Examples of monohydric secondary alcohols include 2-propanol, 2-butanol, cyclohexanol, propylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of monohydric tertiary alcohols include tert-butyl alcohol. Examples of dihydric alcohols include methanediol, ethylene glycol, and propylene glycol. Examples of trihydric alcohols include glycerin.

[0012] As the ketone having 1 to 10 carbon atoms, an aliphatic ketone can be preferably used, such as acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and methyl cyclopentanone.

[0013] As the ether having 1 to 10 carbon atoms, an aliphatic ether can be preferably used, such as dimethyl ether, ethyl methyl ether, diethyl ether, tetrahydrofuran, 1,4-dioxane, etc.

[0014] As the ester having 1 to 10 carbon atoms, an aliphatic ester can be preferably used, for example, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethyl acrylate, propyl acrylate, dimethyl maleate, diethyl maleate, dipropyl maleate, dimethyl adipate, diethyl adipate, dipropyl adipate, etc.

[0015] In the hollow silica aqueous sol and hollow silica organic solvent sol, which are the raw materials, the hollow silica particles can have an average particle size, as measured by dynamic light scattering (DLS), in the range of 20 to 150 nm, 30 to 150 nm, 40 to 150 nm, 50 to 150 nm, 60 to 150 nm, or 60 to 120 nm. ２ The concentration of the particles may be 1 to 50% by weight, or 5 to 40% by weight, and typically 10 to 30% by weight.

[0016] The pH of the sol is alkaline, for example, 7.5 to 12 or 7.5 to 11, but typically can be in the range of 7.5 to 10. The pH is measured when the organic solvent sol and the same mass of pure water are mixed at a 1:1 ratio. While it is possible to measure the pH when using a water-miscible organic solvent as the organic solvent, it is preferable to measure the pH at the methanol solvent sol stage beforehand when replacing the solvent with a hydrophobic organic solvent. For example, for sols whose dispersion medium is a hydrophilic organic solvent, such as methanol sol and propylene glycol monomethyl ether sol, the pH can be measured using a solution obtained by mixing pure water and the sol at a mass ratio of 1:1. For sols whose dispersion medium is a hydrophobic organic solvent, such as methyl ethyl ketone sol, the pH can be measured using a solution obtained by mixing pure water, methanol, and methyl ethyl ketone sol at a mass ratio of 1:1:1.

[0017] Hollow silica organic solvent sol can be obtained by solvent substitution of the aqueous medium of an aqueous sol with an alcohol solvent having 1 to 5 carbon atoms, and if desired, further solvent substitution with an organic solvent, and moisture may remain in the solvent during this process. At the stage of an alcohol sol of hollow silica particles, the sol may contain, for example, 0.1 to 3.0% by mass of residual moisture. And at the stage of an organic solvent sol of hollow silica particles, the sol may contain 0.01 to 0.5% by mass of residual moisture.

[0018] Furthermore, the viscosity of the hollow silica organic solvent sol can be set in the range of 1.0 to 10.0 mPa·s.

[0019] An amine can be added to the hollow silica organic solvent sol of the present invention. The amine used in the present invention can be a water-soluble amine having a water solubility of 80 g / L or more, or 100 g / L or more.

[0020] The raw material hollow silica aqueous sol and the hollow silica organic solvent sol obtained by solvent substitution can contain amine, or amine and ammonia. The amine is used to reduce the SiO ２The amine or the amine and ammonia base component can be added and contained in an amount of 0.001 to 10 mass %, or 0.01 to 10 mass %, or 0.1 to 10 mass % relative to the total mass of the hollow silica particle organic solvent sol. The amount of the amine or the amine and ammonia base component can be expressed as the total nitrogen amount in the hollow silica particle organic solvent sol, and can be contained in an amount of, for example, 10 to 100,000 ppm, or 100 to 10,000 ppm, or 100 to 3,000 ppm, or 100 to 2,000 ppm, typically 200 to 2,000 ppm.

[0021] The amine may be an aliphatic amine or an aromatic amine, with an aliphatic amine being preferred. The amine may be at least one amine selected from the group consisting of primary, secondary, and tertiary amines having 1 to 10 carbon atoms. The amine is water-soluble and is at least one amine selected from the group consisting of primary, secondary, and tertiary amines having 1 to 10 carbon atoms.

[0022] For example, primary amines include monomethylamine, monoethylamine, monopropylamine, monoisopropylamine, monobutylamine, monoisobutylamine, monosecbutylamine, monotertbutylamine, monomethanolamine, monoethanolamine, monopropanolamine, monoisopropanolamine, monobutanolamine, monoisobutanolamine, monosecbutanolamine, and monotertbutanolamine.

[0023] Examples of secondary amines include dimethylamine, diethylamine, dipropylamine, diisopropylamine, N-methylethylamine, N-ethylisobutylamine, dimethanolamine, diethanolamine, dipropanolamine, diisopropanolamine, N-methanolethylamine, N-methylethanolamine, N-ethanolisobutylamine, and N-ethylisobutanolamine.

[0024] Examples of tertiary amines include trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, triisobutylamine, trisecbutylamine, tritertbutylamine, trimethanolamine, triethanolamine, tripropanolamine, triisopropanolamine, tributanolamine, triisobutanolamine, trisecbutanolamine, and tritertbutanolamine.

[0025] As the amine, an amine having a water solubility of 80 g / L or more, or 100 g / L or more can be preferably used. As these amines, primary amines and secondary amines are preferred, and secondary amines are preferred because of their low volatility and high solubility, such as diisopropylamine and diethanolamine.

[0026] In the present invention, the sol contains the above amine, and thus the SiO ２ The surface charge amount calculated per 1 g of the hollow silica particles can be set to 5 μeq / g or more, or 25 μeq / g or more. Typically, it can be set in the range of 5 to 250 μeq / g, or 25 to 250 μeq / g, or 25 to 100 μeq / g, or 25 to 80 μeq / g, or 25 to 50 μeq / g. In the present invention, the surface charge amount of the hollow silica particles can be adjusted to any desired surface charge amount by adjusting the type and amount of the amine mentioned above.

[0027] In the present invention, the surface of hollow silica particles can be coated with a silane compound. As the silane compound, a hydrolyzate of at least one silane compound selected from the group consisting of silane compounds represented by formulas (1) to (3) can be used. 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 via a Si—C bond; R ２each represents an alkoxy group, an acyloxy group, or a halogen group, and a is an integer of 1 to 3. In the above formulas (2) and (3), R ３ and R ５ represents an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms, and is bonded to a silicon atom via 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.

[0028] The alkyl group includes alkyl groups having 1 to 18 carbon atoms, such as 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, a 2,2-dimethyl-n-propyl group, a 1-methyl-n-butyl group, a 2 ... Ethyl-n-propyl group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group ethyl 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-cyclobutyl group cyclobutyl group, 3-ethylcyclobutyl group, 1,2-dimethylcyclobutyl group, 1,3-dimethylcyclobutyl group, 2,2-dimethylcyclobutyl group, 2,3-dimethylcyclobutyl group, 2,4-dimethylcyclobutyl group, 3,3-dimethylcyclobutyl group, 1-n-propylcyclopropyl group, 2-n-propylcyclopropyl group, 1-i-propylcyclopropyl group, 2-i-propylcyclopropyl group, 1,2,2-trimethylcyclopropyl group, 1,2,3-trimethylcyclopropyl group, 2,2,Examples of the cyclopropyl group 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, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl groups.

[0029] The alkylene group may be an alkylene group derived from the alkyl group described above.

[0030] The aryl group may be an aryl group having 6 to 30 carbon atoms, such as a phenyl group, a naphthyl group, an anthracene group, or a pyrene group, but is not limited to these.

[0031] The alkenyl group includes alkenyl groups having 2 to 10 carbon atoms, such as ethenyl, 1-propenyl, 2-propenyl, 1-methyl-1-ethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-n-propylethenyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2-ethyl-2-propenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, and 2-methyl-3-butenyl. , 3-methyl-1-butenyl group, 3-methyl-2-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1-i-propylethenyl group, 1,2-dimethyl-1-propenyl group, 1,2-dimethyl-2-propenyl group, 1-cyclopentenyl group, 2-cyclopentenyl group, 3-cyclopentenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, 1-methyl-1-pentenyl group, 1-methyl-2-pentenyl group, 1-methyl-3-pentenyl group, 1-methyl-4-pentenyl group, 1-n-butylethenyl group, 2-methyl-1-pentenyl group, 2-methyl-2-pentenyl group and the like, but are not limited to these.

[0032] The alkoxy group includes 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, but is not limited to these.

[0033] The acyloxy group includes acyloxy groups having 2 to 10 carbon atoms, such as a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an i-propylcarbonyloxy group, an n-butylcarbonyloxy group, an i-butylcarbonyloxy group, an s-butylcarbonyloxy group, a t-butylcarbonyloxy group, an n-pentylcarbonyloxy group, a 1-methyl-n-butylcarbonyloxy group, a 2-methyl-n-butylcarbonyloxy group, a 3-methyl-n-butylcarbonyloxy group, a 1,1-dimethyl-n-propylcarbonyloxy group, a 1,2-dimethyl-n-propylcarbonyloxy group, a 2,2-dimethyl-n-propylcarbonyloxy group, a 1-ethyl-n-propylcarbonyloxy group, an n-hexylcarbonyloxy group, a 1-methyl-n-pentylcarbonyloxy group, and a 2-methyl-n-pentylcarbonyloxy group.

[0034] The halogen group includes fluorine, chlorine, bromine, iodine, and the like.

[0035] 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 ３ n can be in the range of 1 to 100 or 1 to 10.

[0036] Examples of the organic group having an epoxy group include a 2-(3,4-epoxycyclohexyl)ethyl group and a 3-glycidoxypropyl group.

[0037] 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.

[0038] An example of an organic group having a mercapto group is a 3-mercaptopropyl group.

[0039] 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.

[0040] An example of the organic group having a ureido group is a 3-ureidopropyl group.

[0041] An example of an organic group having a cyano group is a 3-cyanopropyl group.

[0042] The silane 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. In the above formula, R １２ represents an alkoxy group, such as a methoxy group or an ethoxy group. As the silane compound, a silane compound manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

[0043] The silane compound reacts with the hydroxyl groups on the surface of silica particles (e.g., silanol groups in the case of silica particles) to coat the surface of the silica particles with the silane compound through siloxane bonds. The reaction can be carried out at a temperature ranging from 20°C to the boiling point of the dispersion medium, for example, at a temperature ranging from 20°C to 100°C. The reaction can be carried out for about 0.1 to 6 hours.

[0044] The number of silicon atoms in the silane compound relative to the silica particle surface is 0.1 / nm ２ ~6.0 pieces / nm ２ The surface of the hollow silica particles can be coated by adding a silane compound corresponding to the coating amount of the above to the silica sol.

[0045] Water is required for the hydrolysis of the silane compound, but if the sol is an aqueous solvent, that aqueous solvent can be used. Water remaining in the solvent when an aqueous medium is replaced with an organic solvent can also be used. For example, water present in the organic solvent at 0.01 to 1% by mass can be used. Furthermore, hydrolysis can be carried out with or without a catalyst. A catalyst-free hydrolysis is carried out when the silica particle surface is acidic. When a catalyst is used, examples of the hydrolysis catalyst include metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases. Examples of metal chelate compounds used as hydrolysis catalysts include triethoxy mono(acetylacetonato)titanium and triethoxy mono(acetylacetonato)zirconium. Examples of organic acids used as hydrolysis catalysts include acetic acid and oxalic acid. Examples of inorganic acids used as hydrolysis catalysts include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid. Examples of organic bases used as hydrolysis catalysts include pyridine, pyrrole, piperazine, and quaternary ammonium salts. Examples of inorganic bases that serve as hydrolysis catalysts include ammonia, sodium hydroxide, and potassium hydroxide.

[0046] 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.

[0047] In the present invention, a film-forming composition containing the hollow silica organic solvent sol and an organic resin is obtained.

[0048] A film-forming composition can be obtained by selecting and mixing a thermosetting or photocurable organic resin, and then adding a curing agent such as an amine-based curing agent, an acid anhydride-based curing agent, a radical generator-based curing agent (thermal radical generator, photoradical generator), or an acid generator-based curing agent (thermal acid generator, photoacid generator) to form a cured product.

[0049] The film-forming composition of the present invention contains an organic resin and a curing agent, and can be applied to or filled into a substrate and then cured by heating, light irradiation, or a combination thereof. Examples of the organic resin (curable resin) include resins having functional groups such as epoxy groups or (meth)acryloyl groups, and isocyanate-based resins. For example, photocurable polyfunctional acrylates can be preferably used.

[0050] Examples of polyfunctional acrylates include polyfunctional acrylates having difunctional, trifunctional, tetrafunctional, or higher functional groups in the molecule, such as neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. These polyfunctional acrylates can also be described below.

[0051] The film-forming composition of the present invention can contain a surfactant (leveling agent). Examples of surfactants (leveling agents) that can be used include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, and silicone surfactants. The surfactant (leveling agent) can be added in an amount of 0.01 to 5 phr or 0.01 to 1 phr relative to the organic resin.

[0052] 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, monoalkyl phosphates, and alkanesulfonates.

[0053] For example, alkylbenzene sulfonates include sodium salts, potassium salts and lithium salts, such as sodium C10-C16 alkylbenzene sulfonate, C10-C16 alkylbenzene sulfonic acid, and sodium alkylnaphthalene sulfonate.

[0054] Examples of higher alcohol sulfates include sodium dodecyl sulfate (sodium lauryl sulfate) having 12 carbon atoms, triethanolamine lauryl sulfate, and triethanolammonium lauryl sulfate.

[0055] Examples of polyoxyethylene alkyl ether sulfates include polyoxyethylene styrenated phenyl ether sodium sulfate, polyoxyethylene styrenated phenyl ether ammonium sulfate, polyoxyethylene decyl ether sodium sulfate, polyoxyethylene decyl ether ammonium sulfate, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether ammonium sulfate, polyoxyethylene tridecyl ether sodium sulfate, and polyoxyethylene oleyl cetyl ether sodium sulfate.

[0056] Examples of the α-olefin sulfonate include sodium α-olefin sulfonate.

[0057] Examples of the alkane sulfonates include sodium 2-ethylhexyl sulfate.

[0058] Examples of cationic surfactants that can be used in the present invention include alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, and amine salt-based agents.

[0059] Alkyltrimethylammonium salts are quaternary ammonium salts that have a chloride ion or a bromide ion as a counter ion, such as dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, coconut alkyltrimethylammonium chloride, and alkyl(C16-18)trimethylammonium chloride.

[0060] Dialkyldimethylammonium salts have two lipophilic main chains and two methyl groups. Examples include bis(hydrogenated tallow)dimethylammonium chloride, such as didecyldimethylammonium chloride, dicoconuclear alkyldimethylammonium chloride, dihydrogenated tallow alkyldimethylammonium chloride, and dialkyl(C14-18)dimethylammonium chloride.

[0061] Alkyldimethylbenzylammonium salts are quaternary ammonium salts having one lipophilic main chain, two methyl groups, and one benzyl group, and examples thereof include benzauconium chloride, such as alkyl(C8-18)dimethylbenzylammonium chloride.

[0062] Examples of amine salt agents include those in which the hydrogen atom of ammonia has been substituted with one or more hydrocarbon groups, such as N-methylbishydroxyethylamine fatty acid ester hydrochloride.

[0063] 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.

[0064] 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.

[0065] For example, 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.

[0066] Examples of polyoxyethylene alkylphenol ethers include polyoxyethylene styrenated phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzyl phenyl ether.

[0067] Examples of alkyl glucosides include decyl glucoside and lauryl glucoside.

[0068] Examples of polyoxyethylene fatty acid esters include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol dioleate, and polypropylene glycol dioleate.

[0069] 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.

[0070] 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.

[0071] Examples of fatty acid alkanolamides include coconut oil fatty acid diethanolamide, beef tallow fatty acid diethanolamide, lauric acid diethanolamide, and oleic acid diethanolamide.

[0072] 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.

[0073] The silicone surfactant used in the present invention is a compound having a repeating unit containing a siloxane bond in the main chain. Silicone surfactants with a weight-average molecular weight ranging from 500 to 50,000 can be used. These may be modified silicone surfactants, including those with a structure in which an organic group is introduced into the side chain and / or terminal of a polysiloxane. Examples of organic groups include amino groups, epoxy groups, alicyclic epoxy groups, carbinol groups, mercapto groups, carboxyl groups, aliphatic ester groups, aliphatic amide groups, and polyether groups. Examples of silicone surfactants include trade names such as Toray Silicone DC3PA, Toray Silicone SH7PA, Toray Silicone DC11PA, Toray Silicone SH21PA, Toray Silicone SH28PA, Toray Silicone SH29PA, Toray Silicone SH30PA, and Toray Silicone SH8400 (all manufactured by Dow Corning Toray Co., Ltd.), Silwet 1-77, L-7280, L-7001, L-7002, L-7200, L-7210, L-7220, L-7230, L7500, L-7600, L-7602, L-7604, L-7605, L-7622, ​​L-765 7, L-8500, and L-8610. (all manufactured by Momentive Performance Materials), KP-341, KF-6001, KF-6002 (all manufactured by Shin-Etsu Silicones Co., Ltd.), BYK307, BYK323, BYK330 (all manufactured by BYK-Chemie), etc. For example, a polyether-modified silicone under the trade name L-7001 (manufactured by Dowsil Industries) can be suitably used.

[0074] 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 form a film-forming composition containing hollow silica particles and an organic resin.

[0075] When the film-forming composition is a thermosetting film-forming composition, the heat curing agent can be contained in the 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, and for example, the heat curing agent can be contained 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 of the cured resin.

[0076] Examples of heat curing agents include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polymercaptans, acid anhydrides, thermal radical generators, and thermal acid generators. Radical generator-based curing agents, acid anhydride-based curing agents, and amine-based curing agents are particularly preferred. These heat curing agents can be used even if they are solid by dissolving them in a solvent. However, evaporation of the solvent can cause a decrease in the density of the cured product, a decrease in strength due to the generation of pores, and a decrease in water resistance. Therefore, it is preferable that the curing agent itself is liquid at room temperature and normal pressure.

[0077] Examples of the phenol resin include phenol novolac resin and cresol novolac resin.

[0078] 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.

[0079] Examples of polyamide resins include those produced by condensation of dimer acid and polyamine, such as polyamidoamines having a primary amine and a secondary amine in the molecule.

[0080] Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and epoxyimidazole adduct.

[0081] 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.

[0082] 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.

[0083] The thermal acid generator may be a sulfonium salt or a phosphonium salt, but a sulfonium salt is preferably used. For example, the following compounds can be mentioned: In formula (C-1), R represents an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 20 carbon atoms, and an alkyl group having 1 to 12 carbon atoms is particularly preferred.

[0084] Among these, methyltetrahydrophthalic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride (methylnadic anhydride, methylhimic anhydride), hydrogenated methylnadic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, methylhexahydrophthalic anhydride, and a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, which are liquid at room temperature and normal pressure, are preferred. These liquid acid anhydrides have a viscosity of about 10 mPas to 1,000 mPas measured at 25°C.

[0085] 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 are available from Tokyo Chemical Industry Co., Ltd.

[0086] Furthermore, when obtaining the cured product, a curing aid may be used in combination as appropriate. Examples of the curing aid 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 can be contained in a ratio of 0.001 to 0.1 parts by mass per part by mass of the curing agent.

[0087] The composition is obtained as a thermosetting varnish by mixing a resin, a curing agent, and optionally a curing aid, which can be mixed in a reaction vessel using a stirring blade or a kneader.

[0088] The mixing is carried out by a hot mixing method at a temperature of 60°C to 100°C for 0.5 to 1 hour.

[0089] The resulting curable film-forming composition is a thermosetting coating composition and has a viscosity suitable for use, for example, as a liquid encapsulant. The liquid thermosetting film-forming composition can be adjusted to any viscosity and can be used as a transparent encapsulant for LEDs and the like by casting, potting, dispensing, printing, or other methods, allowing for partial encapsulation at any desired location. The liquid thermosetting composition is directly mounted on an LED or the like in its liquid state using the method described above, and then dried and cured to obtain a cured product.

[0090] A thermosetting film-forming composition (thermosetting coating composition) is applied to a substrate and heated at a temperature of 80 to 200° C. to obtain a cured product.

[0091] When the film-forming composition is a photocurable resin composition, the photocuring agent (photoradical generator, photoacid generator) can be contained in the 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 photocuring agent (photoradical generator, photoacid generator) can be contained 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 photocuring agent relative to the curable resin is expressed as the equivalent ratio of the photocuring agent to the functional group of the resin.

[0092] The photoradical generator is not particularly limited as long as it generates radicals directly or indirectly upon irradiation with light.

[0093] Examples of photoradical polymerization initiators as photoradical generators include imidazole compounds, diazo compounds, bisimidazole compounds, N-arylglycine compounds, organic azide compounds, titanocene compounds, aluminate compounds, organic peroxides, N-alkoxypyridinium salt compounds, and thioxanthone compounds. Examples of azide compounds include p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, 4,4'-diazidochalcone, 4,4'-diazidodiphenyl sulfide, and 2,6-bis(4'-azidobenzal)-4-methylcyclohexanone. Examples of diazo compounds include 1-diazo-2,5-diethoxy-4-p-tolylmercaptobenzeneborofluoride, 1-diazo-4-N,N-dimethylaminobenzene chloride, and 1-diazo-4-N,N-diethylaminobenzeneborofluoride. Examples of bisimidazole compounds include 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)1,2'-bisimidazole and 2,2'-bis(o-chlorophenyl)4,5,4',5'-tetraphenyl-1,2'-bisimidazole.Examples of 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).

[0094] 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.

[0095] 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).

[0096] The photoacid generator is not particularly limited as long as it generates an acid directly or indirectly upon irradiation with light.

[0097] 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.

[0098] The onium salt used as the photoacid generator includes iodonium salts such as 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).

[0099] 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.

[0100] Examples of phosphonium salts include triphenylphosphonium chloride, triphenylphosphonium bromide, tri(p-methoxyphenyl)phosphonium tetrafluoroborate, tri(p-methoxyphenyl)phosphonium hexafluorophosphonate, tri(p-ethoxyphenyl)phosphonium tetrafluoroborate, 4-chlorobenzenediazonium hexafluorophosphate, and benzyltriphenylphosphonium hexafluoroantimonate.

[0101] Examples include selenium salts such as triphenylselenium hexafluorophosphate, and metallocene complexes such as (η5 or η6-isopropylbenzene)(η5-cyclopentadienyl)iron(II) hexafluorophosphate.

[0102] The following compounds can also be used as the photoacid generator.

[0103] As the photoacid generator, sulfonium salt compounds and iodonium salt compounds are preferred. The anion species thereof is CF3SO3 － , C ４ F ９ SO3 － , C ８ F １７ SO3 － , camphorsulfonate anion, tosylate anion, BF4 － , PF6 － , AsF6 － and SbF6 － In particular, anion species such as hexafluorophosphate ion and hexafluoroantimonate ion, which exhibit strong acidity, are preferred.

[0104] The film-forming 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.

[0105] Examples of methods for applying the film-forming 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.

[0106] In the present invention, the photo-coating composition (film-forming composition) can be applied to a substrate and cured by light irradiation, or can be heated before or after light irradiation.

[0107] The thickness of the coating film can be selected from the range of about 0.01 μm to 10 mm depending on the application of the cured product. For example, when used as a photoresist, it can be about 0.05 to 10 μm (particularly 0.1 to 5 μm), when used as a printed wiring board, it can be about 5 μm to 5 mm (particularly 100 μm to 1 mm), and when used as an optical thin film, it can be about 0.1 to 100 μm (particularly 0.3 to 50 μm).

[0108] When a transparent coating is obtained, the visible light transmittance of the coating can be set to 80% or more, or 90% or more, typically 90 to 96%.

[0109] When a photoacid generator is used, the light to which the film-forming composition is 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, more preferably about 200 to 400 nm, and particularly about 300 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, or laser light (helium-cadmium laser, excimer laser, etc.) can be used. Such light irradiation causes the curing reaction of the composition to proceed.

[0110] Heating of a coating film of a film-forming composition containing a thermal acid generator, or heating of a coating film of a film-forming composition containing a photoacid generator, which is carried out as necessary before or after light irradiation, is carried out, for example, at about 60 to 250° C., preferably about 100 to 200° C. The heating time can be selected from the range of 3 seconds or more (e.g., about 3 seconds to 5 hours), for example, 5 seconds to 2 hours, preferably about 20 seconds to 30 minutes, and can usually be selected from the range of about 1 minute to 3 hours (e.g., about 5 minutes to 2.5 hours).

[0111] 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. This pattern exposure 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.

[0112] 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.

[0113] The alkaline developer is generally an aqueous solution having a concentration of 10% by mass or less, and preferably an aqueous solution having a concentration of 0.1 to 3.0% by mass. The developer may also be used by adding alcohols or surfactants, each of which is preferably added in an amount of 0.05 to 10 parts by mass per 100 parts by mass of the developer. Among these, an aqueous solution containing 0.1 to 2.38% by mass of tetramethylammonium hydroxide may be used.

[0114] 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., and one or a mixture of two or more of these may be used. In particular, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl lactate, etc. are preferably used.

[0115] In the present invention, an adhesion promoter can be added for the purpose of improving the adhesion between the cured film and the substrate after development. Examples of such 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; Examples of adhesion promoters include silanes such as silane, 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. One or more of the above adhesion promoters can be used alone or in combination. 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. In this specification, the solid content refers to the components of the composition excluding the solvent component.

[0116] The composition of 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 (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.

[0117] 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.

[0118] The above composition has been found to be photocationically polymerizable. The composition of the present invention has a higher curing rate than conventional liquid epoxy compounds (e.g., alicyclic epoxy compounds having an epoxycyclohexyl ring). Because of its fast curing rate, it is possible to reduce the amount of acid generator added or use a weak acid generator. Since metals can be corroded by acid active species remaining after UV irradiation, reducing the amount of acid generator used is important for preventing metal corrosion. The composition of the present invention has a fast curing rate, allowing for thick film curing.

[0119] Curing by UV irradiation can be applied to heat-sensitive materials (equipment). Thermosetting and photocurable materials using the film-forming composition of the present invention are characterized by rapid curing, transparency, and minimal cure shrinkage, and can be used to coat and bond electronic components, optical components (anti-reflective coatings), and precision mechanical components. For example, they can be used to bond components such as 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 personal computer hard disks, CD and DVD player pickups (the part that captures optical information reflected from the disc), speaker cones and coils, motor magnets, circuit boards, electronic components, and internal components of automobile engines.

[0120] The composition of the present invention can be used as a hard coating material for protecting the surfaces of automobile bodies, lamps, electrical appliances, building materials, plastics, etc., and 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.

[0121] The composition of the present invention can be used as an ink material for printing on metals such as aluminum, plastics, etc., and examples of its application include inks for printing on cards such as credit cards and membership cards, switches in electrical appliances and office automation equipment, and keyboards, and inks for inkjet printers for printing on CDs, DVDs, etc.

[0122] The composition of the present invention can be used in a technology for curing resins in combination with three-dimensional CAD to create complex three-dimensional objects, in photolithography for producing models of industrial products, and in coatings, adhesives, optical waveguides, thick-film resists, etc.

[0123] The film-forming composition of the present invention can also be suitably used as an insulating resin for electronic materials such as anti-reflection films, semiconductor encapsulation materials, adhesives for electronic materials, printed wiring board materials, interlayer insulating film materials, and encapsulants for power modules, as well as an insulating resin for use in high-voltage equipment such as generator coils, transformer coils, and gas-insulated switchgears.

[0124] The organic solvent sol of hollow silica particles of the present invention can be produced by a method including the following steps (A) to (C): step (A): preparing an aqueous sol of hollow silica, step (B): adding at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines having a water solubility of 80 g / L or more and having 1 to 10 carbon atoms to the aqueous sol of hollow silica in step (A), thereby forming a SiO of the hollow silica. ２ (C) a step of solvent-substituting the aqueous medium of the aqueous sol of hollow silica particles obtained in (B) with an alcohol, ketone, ether, or ester having 1 to 10 carbon atoms.

[0125] The hollow silica particles used in step (A) have a silica shell and a space inside the shell. Hollow silica can be obtained by forming a silica-based shell on the surface of a core-corresponding portion, known as a template, in an aqueous dispersion medium, and then removing the core-corresponding portion. The template can be an organic material (e.g., hydrophilic organic resin particles such as polyethylene glycol, polystyrene, or polyester) or an inorganic material (e.g., hydrophilic inorganic compound particles such as calcium carbonate or sodium aluminate).

[0126] In step (B), an amine is added to the hollow silica aqueous sol of step (A). The amine has a water solubility of 80 g / L or more, or 100 g / L or more, and at least one amine selected from primary to tertiary amines having a total of 1 to 10 carbon atoms is added to the SiO of the hollow silica. ２ The amine can be added in a proportion of 0.001 to 10% by mass based on the total mass of the amine.

[0127] Step (C) is a step of solvent-substituting the aqueous medium of the aqueous sol of hollow silica obtained in step (B) with an alcohol, ketone, ether, or ester having 1 to 10 carbon atoms. The aqueous medium of the aqueous sol of hollow silica can be substituted with an organic solvent, or the aqueous medium of the aqueous sol can be substituted with a hydrophilic organic solvent and then with a hydrophobic organic solvent. That is, step (C) is a step of solvent-substituting the aqueous medium of the aqueous sol with an alcohol having 1 to 10 carbon atoms, and then further solvent-substituting the alcohol solvent with a ketone, ether, or ester having 1 to 10 carbon atoms.

[0128] During or after the step (C), a step (D) can be added in which at least one silane compound selected from the group consisting of the silane compounds represented by the formulas (1), (2), and (3) is added and heated.

[0129] That is, the process may be a step (D) in which the aqueous medium of the aqueous sol in step (C) is solvent-substituted with an alcohol having 1 to 10 carbon atoms, followed by adding at least one silane compound selected from the group consisting of silane compounds represented by formula (1), formula (2), and formula (3), and heating, followed by a further step of solvent-substitution of the alcohol solvent in step (C) with a ketone, ether, or ester having 1 to 10 carbon atoms.

[0130] The heating temperature after the addition of the silane compound is 40° C. or higher, preferably the reflux temperature of the solvent used or lower, and the heating time can be in the range of 0.1 to 10 hours.

[0131] In the present invention, the surface charge of hollow silica particles can be adjusted as desired using the above-mentioned method for producing hollow silica organic solvent sol.

[0132] (Analysis method) [SiO ２Concentration Measurement] The hollow silica sol was placed in a crucible and dried by heating on a hot plate at a temperature approximately 10°C higher than the boiling point of the dispersant to remove the dispersant. The resulting silica gel was then calcined at 1000°C, and the calcination residue was weighed and calculated. [Moisture Measurement] Measured by Karl Fischer titration. [Viscosity Measurement] Measured at 25°C using a BL-type viscometer. [pH Measurement] Measured at 25°C using a pH meter (manufactured by Toa DKK Corporation). For methanol sol and propylene glycol monomethyl ether sol, measurements were made using a solution in which pure water and the sol were mixed at a mass ratio of 1:1. For methyl ethyl ketone sol, measurements were made using a solution in which pure water, methanol, and methyl ethyl ketone sol were mixed at a mass ratio of 1:1:1. [Total Nitrogen Measurement] Measurements were made using a trace total nitrogen analyzer (TN) (TN-2100V, manufactured by Mitsubishi Chemical Analytech Corporation) under the following conditions. Pyrolysis furnace Inlet temperature: 800°C, Outlet temperature: 900°C Ar (argon) flow rate: 100 mL / min, O ２ (Oxygen) Flow rate: 500 mL / min Detector (chemiluminescence detector) Low concentration mode O ３ Ozone flow rate: 600 mL / min. Measurement samples were prepared by diluting hollow silica sol to a predetermined volume with methyl ethyl ketone using a measuring flask so that the total nitrogen content was 1 to 10 ppm. 20 μL of the measurement sample was injected into the device, and the area value was measured. The total nitrogen content of the measurement sample was calculated from a calibration curve created from the area values ​​of previously prepared standard samples with total nitrogen contents of 0 ppm, 1 ppm, and 10 ppm. [Dynamic Light Scattering Particle Size Measurement] Measurement was performed using a dynamic light scattering particle size measurement device (Spectris Zetasizer Nano). [Surface Charge Measurement] The measurement sample was prepared by adding and diluting 10 mL of methanol to a silica concentration of approximately 0.5% by mass. Using a particle charge meter (trade name PCD-06, manufactured by Voith Turbo Co., Ltd.), a N / 1000 DADMAC solution (manufactured by Voith Turbo Co., Ltd.) was used as a standard cation titrant to measure the titration value until the streaming potential of the measurement sample reached zero. The titration value thus obtained was divided by the mass of silica contained in the measurement sample to determine the SiO of the hollow silica particles. ２The surface charge (μeq / g) was calculated per 1 g of silica sol. [Measurement of specific surface area by BET (nitrogen gas adsorption method)] The cationic components in the hollow silica sol were removed with an H-type cation exchange resin, and the dried product obtained by removing the solvent by heat treatment was pulverized in a mortar and further treated at 250°C for 2 hours. The specific surface area of ​​this dried and pulverized product was measured using a gas adsorption specific surface area measurement device (Monosorb™ MS-22, manufactured by Quantachrome Instruments Inc.) at 250°C. ２ A mixed gas of 30% nitrogen and 70% helium was used as the carrier gas, and the measurement was performed by the BET single-point method. [Measurement of average primary particle diameter by TEM (transmission electron microscope)] Particles in the hollow silica sol were photographed using a transmission electron microscope (JEM-F200, manufactured by JEOL Ltd.), and approximately 300 arbitrarily selected particles were binarized using an automatic image processing analyzer (LUZEX' AP, manufactured by Nireco Corporation), and the diameter obtained by converting the projected area into a circle was measured as the average primary particle diameter (HEYWOOD diameter). [Calculation of specific surface area ratio] The BET specific surface area value was calculated from the average primary particle diameter measured by TEM to obtain a true density of 2.2 g / cm. ３ The value obtained by dividing the specific surface area by the specific surface area calculated assuming the particles to be spherical was defined as the specific surface area ratio.

[0133] (Example 1) (Preparation of hollow silica methanol sol (1)) A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ The concentration was 20.7% by mass, pH was 9.0, the particle size measured by dynamic light scattering was 88 nm, and the specific surface area measured by BET method was 107 m ２ 100.22 g of a 500 mL recovery flask containing 100.22 g of a 500 mL silica methanol sol (having an average primary particle diameter of 82 nm by TEM, a specific surface area ratio of 3.2, and a specific surface area of ​​100.22 g) was placed in a 500 mL recovery flask, and while stirring with a magnetic stirrer, 0.04 g of diisopropylamine was added and mixed for 2 hours. 38.09 g of methanol was then added with further stirring and mixed for 2 hours. Using a rotary evaporator, water was distilled off while feeding about 3000 mL of methanol under reduced pressure (pressure 150 Torr, bath temperature 80°C), to obtain hollow silica methanol sol (1). The obtained hollow silica methanol sol contained SiO ２Concentration 15.5% by mass, water content 1.7%, viscosity 1.8 mPa·sec, pH 8.2, particle size by dynamic light scattering 99 nm, total nitrogen content 438 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 26 μeq / g.

[0134] (Preparation of film containing hollow silica methanol sol (1)) 18.33 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name KAYARAD DPHA) as a UV curable resin was weighed into a brown bottle, and a UV curing agent (Omnirad 819) was added thereto in an amount of 5 phr, and a leveling agent (manufactured by Dowsil Corporation, trade name L-7001) was added thereto in an amount of 0.1 phr, and the mixture was dissolved in 34.99 g of propylene glycol monomethyl ether to prepare a UV curable resin liquid (concentration: 35% by mass). The hollow silica methanol sol (1) (SiO ２ 1.61 g of the hollow silica methanol sol (1) (concentration: 15.5 mass%) was weighed into a brown bottle, and propylene glycol monomethyl ether and methanol were added to a total of 5.00 g so that the final solvent composition was propylene glycol monomethyl ether / methanol = 6 / 4 by weight ratio, and 0.71 g of the UV curable resin solution prepared above was added, and the mixture was mixed at room temperature for 1 hour to prepare a hollow silica methanol sol (1) / UV curable resin mixed varnish. The solid content was 10 mass %, and the hollow silica (SiO ２ The blending amount of the hollow silica methanol sol (1) / UV curable resin mixed varnish obtained was dropped into a glass substrate in an amount of about 2 mL, and the mixture was uniformly spread on the glass substrate using a spin coater (Mikasa Co., Ltd., Opticoat MS-B100) under the following conditions: 200 rpm x 5 sec, increased to 1000 rpm in 3 sec, and 1000 rpm x 30 sec. Thereafter, the mixture was baked on a hot plate at 100°C x 3 min, with an accumulated light dose of 2000 mJ / cm. ２A film formed from a varnish containing hollow silica methanol sol (1) was prepared by irradiating UV light under the conditions. The total light transmittance of the resulting blended film was measured using a spectroscopic haze meter (Nippon Denshoku Industries Co., Ltd., SH7000) and was found to be 91.6%. This was a high value compared to the total light transmittance of a glass substrate (91.0%) and a film prepared under the same conditions using only a UV-curable resin (90.7%), demonstrating that the blended film was highly transparent.

[0135] (Example 2) (Preparation of hollow silica methanol sol (2)) A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ Concentration 20.7%, pH 9.0, dynamic light scattering particle size 88 nm, specific surface area 107 m by BET method ２ 100.01 g of a silica sol (having a specific surface area of ​​3.2 / g, an average primary particle diameter of 82 nm by TEM, and a specific surface area ratio of 3.2) was placed in a 500 mL recovery flask, and the procedure was carried out in the same manner as in Example 1, except that the amount of diisopropylamine added was changed to 0.10 g and the amount of methanol to 37.98 g, to obtain a hollow silica methanol sol (2). The obtained hollow silica methanol sol (2) contained SiO ２ Concentration 15.1% by mass, water content 0.9%, viscosity 1.6 mPa·sec, pH 8.7, particle size by dynamic light scattering 108 nm, total nitrogen content 409 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 25 μeq / g.

[0136] (Preparation of hollow silica propylene glycol monomethyl ether sol (1)) The hollow silica methanol sol (2) (SiO ２ A 200 mL recovery flask was charged with 42.66 g of propylene glycol monomethyl ether (concentration: 18.2 mass%), and 7.36 g of propylene glycol monomethyl ether was added. Then, using a rotary evaporator, the bath temperature was 60° C. and the pressure was gradually reduced from 150 Torr to 80 Torr, and while feeding 60 g of propylene glycol monomethyl ether, methanol was distilled off to obtain a hollow silica propylene glycol monomethyl ether sol. The obtained hollow silica propylene glycol monomethyl ether sol (1) contained SiO２ The concentration was 13.4% by mass, the water content was 0.2%, the viscosity was 3.5 mPa·sec, the pH was 8.1, the particle size measured by dynamic light scattering was 103 nm, and the total nitrogen content was 330 ppm.

[0137] (Preparation of membrane containing hollow silica methanol sol (2)) The hollow silica methanol sol (2) (SiO ２ A film formed from a hollow silica methanol sol (2) / UV curable resin mixed varnish and a varnish containing hollow silica methanol sol (2) was prepared by the same procedure as in Example 1, except that 1.66 g of hollow silica methanol sol (2) (concentration: 15.1 mass%) was used. The total light transmittance of the obtained blended film was 92.8%, and it was a highly transparent blended film.

[0138] (Preparation of a film formed from a varnish containing hollow silica propylene glycol monomethyl ether sol (1)) The hollow silica propylene glycol monomethyl ether sol (1) (SiO ２ A film formed from a hollow silica propylene glycol monomethyl ether sol (1) / UV curable resin mixed varnish and a varnish containing hollow silica propylene glycol monomethyl ether sol (1) was prepared by the same procedure as in Example 1, except that 1.86 g of propylene glycol monomethyl ether sol (1) (concentration: 13.4 mass%) was used. The total light transmittance of the obtained blended film was 92.2%, making it a highly transparent blended film.

[0139] (Example 3) (Preparation of hollow silica methanol sol (3)) A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ Concentration 20.7%, pH 9.0, dynamic light scattering particle size 88 nm, specific surface area 107 m by BET method ２ 100.15 g of a silica sol (having a specific surface area of ​​3.2 / g, an average primary particle diameter of 82 nm by TEM, and a specific surface area ratio of 3.2) was placed in a 500 mL recovery flask, and the procedure was carried out in the same manner as in Example 1, except that the amount of diisopropylamine added was changed to 0.21 g and the amount of methanol to 38.02 g, to obtain a hollow silica methanol sol (3). The obtained hollow silica methanol sol (3) contained SiO ２Concentration 15.5% by mass, water content 1.6%, viscosity 1.8 mPa·sec, pH 8.6, particle size by dynamic light scattering 101 nm, total nitrogen content 410 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 25 μeq / g.

[0140] (Preparation of hollow silica methyl ethyl ketone sol (1)) The hollow silica methanol sol (3) (SiO ２ 50.02 g of the resulting solution (concentration: 15.5 mass%) was placed in a 200 mL recovery flask, and 0.35 g of 3-methacryloxypropyltrimethoxysilane was added as a surface treatment agent. The solution was heated under reflux with stirring for 5 hours to perform a surface treatment. Thereafter, using a rotary evaporator, the bath temperature was set at 75°C and the pressure was gradually reduced from 500 Torr to 400 Torr, and 150 mL of methyl ethyl ketone was fed in while distilling off the methanol, thereby obtaining hollow silica methyl ethyl ketone sol (1). The obtained hollow silica methyl ethyl ketone sol (1) contained SiO ２ The concentration was 15.5% by mass, the water content was 0.1%, the viscosity was 3.1 mPa·sec, the pH was 7.8, the particle size measured by dynamic light scattering was 106 nm, and the total nitrogen content was 360 ppm.

[0141] (Preparation of membrane containing hollow silica methanol sol (3)) The hollow silica methanol sol (3) (SiO ２ Films formed from hollow silica methanol sol (3) / UV curable resin mixed varnish and a varnish containing hollow silica methanol sol (3) were prepared by the same procedure as in Example 1, except that 1.61 g of hollow silica methanol sol (3) (concentration 15.5 mass%) was used. The total light transmittance of the obtained blended film was 92.1%, and it was a blended film with high transparency. (Preparation of film containing hollow silica methyl ethyl ketone sol (1)) The hollow silica methyl ethyl ketone sol (1) (SiO ２1.61 g of hollow silica methyl ethyl ketone sol (1) (concentration: 15.5 mass%) was weighed into a brown bottle, and propylene glycol monomethyl ether and methyl ethyl ketone were added to a total of 5.00 g so that the final solvent composition was propylene glycol monomethyl ether / methyl ethyl ketone = 6 / 4 by weight. 0.71 g of the UV-curable resin solution prepared in Example 1 was added, and the mixture was mixed at room temperature for 1 hour to prepare a hollow silica methyl ethyl ketone sol (1) / UV-curable resin mixed varnish. The solid content was 10 mass %, and the hollow silica (SiO ２ The blending amount of methyl ethyl ketone sol (1) and UV-curable resin was 100 phr. Approximately 2 mL of the obtained hollow silica methyl ethyl ketone sol (1) / UV-curable resin mixed varnish was dropped onto a glass substrate, and a spin coater (Mikasa Co., Ltd., Opticoat MS-B100) was used to spread the mixture evenly on the glass substrate under the following conditions: 200 rpm x 5 sec, increased to 1000 rpm in 3 sec, and 1000 rpm x 30 sec. Thereafter, the mixture was baked on a hot plate at 100°C x 3 min, with an accumulated light dose of 2000 mJ / cm. ２ A film formed from a varnish containing hollow silica methyl ethyl ketone sol (1) was prepared by irradiating UV light under the conditions. The total light transmittance of the resulting blended film was measured using a spectroscopic haze meter (Nippon Denshoku Industries Co., Ltd., SH7000) and was found to be 92.8%. This was a high value compared to the total light transmittance of the glass substrate (91.0%) and the total light transmittance of a film prepared under the same conditions using only a UV-curable resin (90.7%), making it a blended film with high transparency.

[0142] (Example 4) (Preparation of hollow silica methanol sol (4)) A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ Concentration 20.7%, pH 9.0, dynamic light scattering particle size 88 nm, specific surface area 107 m by BET method ２ 100.05 g of a silica sol (having a specific surface area of ​​3.2 / g, an average primary particle diameter of 82 nm by TEM, and a specific surface area ratio of 3.2) was placed in a 500 mL recovery flask, and the procedure was carried out in the same manner as in Example 1, except that the amount of diisopropylamine added was changed to 0.50 g and the amount of methanol to 38.06 g, to obtain a hollow silica methanol sol (4). The obtained hollow silica methanol sol (4) contained SiO ２Concentration 15.5% by mass, water content 1.2%, viscosity 1.7 mPa·sec, pH 8.9, particle size by dynamic light scattering 99 nm, total nitrogen content 458 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 30 μeq / g.

[0143] (Preparation of hollow silica methyl ethyl ketone sol (2)) The hollow silica methanol sol (4) (SiO ２ A hollow silica methyl ethyl ketone sol (2) was obtained by the same procedure as in Example 3, except that 50.03 g of 3-methacryloxypropyltrimethoxysilane (concentration: 15.5%) was added to a 200 mL recovery flask and the amount of 3-methacryloxypropyltrimethoxysilane added as a surface treatment agent was changed to 0.35 g. The obtained hollow silica methyl ethyl ketone sol (2) contained SiO ２ The concentration was 15.6% by mass, the water content was 0.2%, the viscosity was 3.3 mPa·sec, the pH was 8.3, the particle size measured by dynamic light scattering was 102 nm, and the total nitrogen content was 387 ppm.

[0144] (Preparation of membrane containing hollow silica methanol sol (4)) The hollow silica methanol sol (4) (SiO ２ Films formed from hollow silica methanol sol (4) / UV curable resin mixed varnish and a varnish containing hollow silica methanol sol (4) were prepared by the same procedure as in Example 1, except that 1.61 g of hollow silica methanol sol (4) (concentration 15.5 mass%) was used. The total light transmittance of the obtained blended film was 92.4%, and it was a blended film with high transparency. (Preparation of film containing hollow silica methyl ethyl ketone sol (2)) The hollow silica methyl ethyl ketone sol (2) (SiO ２ A film formed from a hollow silica methyl ethyl ketone sol (2) / UV curable resin mixed varnish and a varnish containing hollow silica methyl ethyl ketone sol (2) was prepared by the same procedure as in Example 3, except that 1.61 g of hollow silica methyl ethyl ketone sol (2) (concentration: 15.6 mass%) was used. The total light transmittance of the obtained blended film was 92.3%, making it a highly transparent blended film.

[0145] (Example 5) (Preparation of hollow silica methanol sol (5)) A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ Concentration 20.7% by mass, pH 9.0, particle size by dynamic light scattering method 88 nm, specific surface area by BET method 107 m ２ 100.15 g of a silica sol (having a specific surface area of ​​3.2 / g, an average primary particle diameter of 82 nm by TEM, and a specific surface area ratio of 3.2) was placed in a 500 mL recovery flask, and the procedure was carried out in the same manner as in Example 1, except that the amount of diisopropylamine added was changed to 1.00 g and the amount of methanol to 38.07 g, to obtain a hollow silica methanol sol (5). The obtained hollow silica methanol sol (5) contained SiO ２ Concentration 15.5% by mass, water content 0.8%, viscosity 1.6 mPa·sec, pH 8.5, particle size by dynamic light scattering 98 nm, total nitrogen content 414 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 27 μeq / g.

[0146] (Preparation of hollow silica methyl ethyl ketone sol (3)) The hollow silica methanol sol (5) (SiO ２ A hollow silica methyl ethyl ketone sol (3) was obtained by the same procedure as in Example 3, except that 50.05 g of the sol (3) (concentration: 15.5 mass%) was placed in a 200 mL recovery flask and the amount of 3-methacryloxypropyltrimethoxysilane added as a surface treatment agent was changed to 0.35 g. The obtained hollow silica methyl ethyl ketone sol (3) contained SiO ２ The concentration was 15.5% by mass, the water content was 0.0%, the viscosity was 2.7 mPa·sec, the pH was 7.9, the particle size measured by dynamic light scattering was 103 nm, and the total nitrogen content was 359 ppm.

[0147] (Preparation of membrane containing hollow silica methanol sol (5)) The hollow silica methanol sol (5) (SiO ２ Films formed from hollow silica methanol sol (5) / UV curable resin mixed varnish and varnish containing hollow silica methanol sol (5) were prepared by the same procedure as in Example 1, except that 1.61 g of hollow silica methanol sol (5) (concentration: 15.5 mass%) was used. The total light transmittance of the obtained blended film was 92.7%, and it was a highly transparent blended film.

[0148] (Preparation of a membrane containing hollow silica methyl ethyl ketone sol (3)) The hollow silica methyl ethyl ketone sol (3) (SiO ２ Films formed from hollow silica methyl ethyl ketone sol (3) / UV curable resin mixed varnish and varnish containing hollow silica methyl ethyl ketone sol (3) were prepared by the same procedure as in Example 3, except that 1.61 g of hollow silica methyl ethyl ketone sol (3) (concentration 15.5 mass%) was used. The total light transmittance of the obtained blended film was 92.8%, making it a highly transparent blended film.

[0149] (Example 6) (Preparation of hollow silica methanol sol (6)) A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ Concentration 20.7%, pH 9.0, dynamic light scattering particle size 88 nm, specific surface area 107 m by BET method ２ 100.06 g of a sol (having a specific surface area ratio of 3.2, an average primary particle diameter of 82 nm by TEM, and a specific surface area ratio of 3.2) was placed in a 500 mL recovery flask, and while stirring the sol with a magnetic stirrer, 1.41 g of 28% aqueous ammonia was added and mixed for 2 hours. 0.04 g of diisopropylamine was then added with stirring and mixed for 2 hours, and 38.01 g of methanol was added with stirring and mixed for 2 hours. Using a rotary evaporator, water was distilled off while feeding about 3000 mL of methanol under reduced pressure (pressure 150 Torr, bath temperature 80°C), to obtain hollow silica methanol sol (6). The obtained hollow silica methanol sol (6) contained SiO ２ Concentration 15.7% by mass, water content 1.1%, viscosity 1.7 mPa·sec, pH 9.0, particle size by dynamic light scattering 99 nm, total nitrogen content 553 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 30 μeq / g.

[0150] (Preparation of hollow silica methyl ethyl ketone sol (4)) The hollow silica methanol sol (6) (SiO ２A hollow silica methyl ethyl ketone sol (4) was obtained by the same procedure as in Example 3, except that 50.00 g of the sol (15.7 mass%) was placed in a 200 mL recovery flask and the amount of 3-methacryloxypropyltrimethoxysilane added as a surface treatment agent was changed to 0.35 g. The obtained hollow silica methyl ethyl ketone sol (4) contained SiO ２ The concentration was 15.6% by mass, the water content was 0.3%, the viscosity was 4.2 mPa·sec, the pH was 8.5, the particle size measured by dynamic light scattering was 103 nm, and the total nitrogen content was 436 ppm.

[0151] (Preparation of membrane containing hollow silica methanol sol (6)) The hollow silica methanol sol (6) (SiO ２ Films formed from hollow silica methanol sol (6) / UV curable resin mixed varnish and a varnish containing hollow silica methanol sol (6) were prepared by the same procedure as in Example 1, except that 1.59 g of hollow silica methanol sol (6) (concentration 15.7 mass%) was used. The total light transmittance of the obtained blended film was 92.7%, and it was a blended film with high transparency. (Preparation of film containing hollow silica methyl ethyl ketone sol (4)) The hollow silica methyl ethyl ketone sol (4) (SiO ２ Films formed from hollow silica methyl ethyl ketone sol (4) / UV curable resin mixed varnish and varnish containing hollow silica methyl ethyl ketone sol (4) were prepared by the same procedure as in Example 3, except that 1.61 g of hollow silica methyl ethyl ketone sol (4) (concentration: 15.6 mass%) was used. The total light transmittance of the obtained blended film was 92.1%, making it a highly transparent blended film.

[0152] (Example 7) (Preparation of hollow silica methanol sol (7)) A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ Concentration 20.7% by mass, pH 9.0, particle size by dynamic light scattering method 88 nm, specific surface area by BET method 107 m ２105.47 g of a silica-based sol (having a specific surface area of ​​3.2 / g, an average primary particle diameter of 82 nm by TEM, and a specific surface area ratio of 3.2) was placed in a 500 mL recovery flask, and the procedure was carried out in the same manner as in Example 1, except that the amount of 28% aqueous ammonia added was changed to 3.77 g, the amount of diisopropylamine to 0.05 g, and the amount of methanol to 40.07 g, to obtain a hollow silica methanol sol (7). The obtained hollow silica methanol sol (7) contained SiO ２ Concentration 15.5% by mass, water content 1.1%, viscosity 1.4 mPa sec, pH 9.3, particle size by dynamic light scattering 101 nm, total nitrogen content 1346 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 36 μeq / g.

[0153] (Preparation of hollow silica methyl ethyl ketone sol (5)) The hollow silica methanol sol (7) (SiO ２ A hollow silica methyl ethyl ketone sol (5) was obtained by the same procedure as in Example 3, except that 50.02 g of the sol (15.5 mass%) was placed in a 200 mL recovery flask and the amount of 3-methacryloxypropyltrimethoxysilane added as a surface treatment agent was changed to 0.35 g. The obtained hollow silica methyl ethyl ketone sol (5) contained SiO ２ The concentration was 15.5% by mass, the water content was 0.1%, the viscosity was 2.8 mPa·sec, the pH was 8.4, the particle size measured by dynamic light scattering was 102 nm, and the total nitrogen content was 1043 ppm.

[0154] (Preparation of membrane containing hollow silica methanol sol (7)) The hollow silica methanol sol (7) (SiO ２ Films formed from hollow silica methanol sol (7) / UV curable resin mixed varnish and varnish containing hollow silica methanol sol (7) were prepared by the same procedure as in Example 1, except that 1.61 g of hollow silica methanol sol (7) (concentration: 15.5 mass%) was used. The total light transmittance of the obtained blended film was 92.7%, and it was a highly transparent blended film.

[0155] (Preparation of a membrane containing hollow silica methyl ethyl ketone sol (5)) The hollow silica methyl ethyl ketone sol (5) (SiO ２Films formed from hollow silica methyl ethyl ketone sol (5) / UV curable resin mixed varnish and varnish containing hollow silica methyl ethyl ketone sol (5) were prepared by the same procedure as in Example 3, except that 1.61 g of hollow silica methyl ethyl ketone sol (5) (concentration 15.5 mass%) was used. The total light transmittance of the obtained blended film was 92.4%, making it a highly transparent blended film.

[0156] (Example 8) (Preparation of hollow silica methanol sol (8)) A commercially available hollow silica aqueous sol (HKT-A20-40D, manufactured by Ningbo Dilato Co., Ltd., SiO ２ Concentration 20.0%, pH 9.3, dynamic light scattering particle size 55 nm, specific surface area 116 m by BET method ２ 551.10 g of the sol (having a molecular weight of 1.8 / g, an average primary particle diameter of 43 nm by TEM, and a specific surface area ratio of 1.8) was placed in a 2000 mL recovery flask, and while stirring with a magnetic stirrer, 0.55 g of diethanolamine was added and mixed for 2 hours. 139.76 g of methanol was then added with further stirring and mixed for 2 hours. Using a rotary evaporator, water was distilled off while feeding about 12000 mL of methanol under reduced pressure (pressure 580 Torr, bath temperature 120°C), to obtain hollow silica methanol sol (8). The obtained hollow silica methanol sol (8) contained SiO ２ Concentration 23.5%, water content 0.6%, viscosity 2.8 mPa·sec, pH 9.0, dynamic light scattering particle size 63 nm, total nitrogen content 641 ppm, SiO of hollow silica particles ２ The surface charge amount calculated per gram of the powder was 34 μeq / g.

[0157] (Preparation of hollow silica methyl ethyl ketone sol (6)) The SiO of hollow silica methanol sol (8) obtained in Example 8 ２25.00 g of raw material methanol sol, the concentration of which was adjusted to 20.5% by mass, was placed in a 300 mL recovery flask, and 8.20 g of methanol and 0.26 g of pure water were added. The mixture was stirred with a magnetic stirrer. 0.25 g of γ-methacryloxypropyltrimethoxysilane was added as a surface treatment agent, and the mixture was heated under reflux for 5 hours to perform a surface treatment. Then, using a rotary evaporator, the bath temperature was set at 75°C, the pressure was gradually reduced from 500 Torr to 400 Torr, and about 80 mL of methyl ethyl ketone was added while distilling off the methanol, to obtain hollow silica methyl ethyl ketone sol (6). The obtained hollow silica methyl ethyl ketone sol (6) contained SiO ２ The concentration was 22.4%, the water content was 0.4%, the pH was 9.3, and the particle size as measured by dynamic light scattering was 66 nm.

[0158] (Comparative Example 1) Preparation of amine-free hollow silica methanol sol A commercially available hollow silica aqueous sol (HKT-D20-225-1, manufactured by Ningbo Dilato Co., Ltd., SiO ２ A 500 mL recovery flask was charged with 100.04 g of the resulting solution (concentration: 20.7%, pH: 9.0, particle size by dynamic light scattering: 88 nm), and 38.02 g of methanol was then added. An attempt was made to prepare a hollow silica methanol sol by distilling off water while feeding about 3,000 mL of methanol into a rotary evaporator under reduced pressure (pressure: 150 Torr, bath temperature: 80°C). However, viscosity increased and gelation occurred during the substitution with methanol, and the desired hollow silica methanol sol was not obtained.

[0159]

[0160]

[0161] In Tables 1 and 2, (hollow silica methanol sol) indicates a sol in which hollow silica particles are dispersed in methanol. MeOH in the (dispersion medium) column indicates methanol. (pH) indicates the pH when the hollow silica methanol sol is mixed with the same mass of pure water at a 1:1 ratio. (Amine amount) indicates the SiO of the hollow silica particles. ２The addition ratio (mass %) of the hollow silica particles to the hollow silica methanol sol is shown, and the hollow silica methanol sol contained the hollow silica particles according to the addition ratio. (DLS) indicates the average particle size (nm) of the hollow silica particles measured by dynamic light scattering. (Total nitrogen content) indicates the total nitrogen content (ppm) of the amine or the basic component consisting of amine and ammonia in the hollow silica particle sol. (Surface charge amount) indicates the SiO ２ The surface charge amount (μeq / g) calculated per 1 g of the hollow silica sol is shown. Note that gelation indicates that the hollow silica sol has gelled and the physical properties cannot be measured.

[0162]

[0163] In Table 3, (hollow silica organic solvent sol) refers to a sol in which hollow silica particles are dispersed in an organic solvent. In the (Dispersion Medium) column, PGME refers to propylene glycol monomethyl ether, and MEK refers to methyl ethyl ketone. (pH) for propylene glycol monomethyl ether sol refers to the pH value measured in a solution prepared by mixing pure water and the sol at a mass ratio of 1:1. For methyl ethyl ketone sol, it refers to the pH value measured in a solution prepared by mixing pure water, methanol, and methyl ethyl ketone sol at a mass ratio of 1:1:1. In the (Surface Treatment) column, "none" indicates that the silica particles were not surface-treated with a silane coupling agent, and MPS indicates that the silica particles were surface-treated with 3-methacryloxypropyltrimethoxysilane. (DLS) indicates the average particle size (nm) of the hollow silica particles measured by dynamic light scattering. (Total Nitrogen Amount) refers to the total nitrogen amount (ppm) of the amine or base component consisting of amine and ammonia in the hollow silica particle sol.

[0164]

[0165]

[0166] In Tables 4 and 5, (hollow silica methanol sol blended film) indicates a film obtained by coating a substrate with a resin composition in which a sol of hollow silica particles dispersed in methanol was blended with a UV-curable resin and then photocuring the film. The (UV-curable resin) column indicates the polyfunctional acrylate used, and DPHA indicates KAYARAD DPHA (polyfunctional acrylate: component: dipentaerythritol hexaacrylate), manufactured by Nippon Kayaku Co., Ltd. (blended amount) indicates the blended amount (phr) of hollow silica particles relative to the UV-curable resin. (Total light transmittance) indicates the total light transmittance (%) of the resulting coating.

[0167]

[0168]

[0169] In Tables 6 and 7, (hollow silica organic solvent sol blended film) shows a film obtained by coating a substrate with a resin composition in which a sol of hollow silica particles dispersed in an organic solvent was blended with a UV-curable resin and then photocuring the film. The (UV-curable resin) column indicates the polyfunctional acrylate used, and DPHA indicates KAYARAD DPHA (polyfunctional acrylate: component: dipentaerythritol hexaacrylate), manufactured by Nippon Kayaku Co., Ltd. (blended amount) indicates the blended amount (phr) of hollow silica particles relative to the UV-curable resin. (Total light transmittance) indicates the total light transmittance (%) of the resulting coating.

[0170] From the above evaluation results, when the aqueous medium was replaced with methanol without adding a water-soluble amine to the hollow silica aqueous sol, thickening and gelation occurred during the solvent replacement process, and the desired hollow silica methanol sol could not be obtained. In contrast, when a predetermined amount of diisopropylamine as a water-soluble amine was added to the hollow silica aqueous sol for solvent replacement, thickening and gelation were avoided, and it was confirmed that it was possible to control the sol to a hollow silica particle with a surface charge amount above a certain value. Furthermore, it was confirmed that the blended film prepared by blending the obtained hollow silica methanol sol with a resin had excellent dispersion uniformity of the hollow silica particles in the resin, resulting in high transparency (total light transmittance). Furthermore, it was confirmed that using the obtained hollow silica methanol sol as a raw material allowed for solvent replacement with other organic solvents, such as propylene glycol monomethyl ether and methyl ethyl ketone.

[0171] The present invention provides an organic solvent sol of hollow silica particles that have a specific surface charge and are highly dispersible in resins, and that contain an amine in the sol and have a space inside the outer shell; a method for producing the same; and a coating-forming composition.

Claims

1. An organic solvent sol containing an amine, comprising hollow silica particles with an internal space within their outer shell.

2. The sol according to claim 1, wherein the amine is at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines having 1 to 10 carbon atoms.

3. The sol according to claim 1 or claim 2, wherein the amine has a water solubility of 80 g / L or more.

4. The amine content of the above amine is the SiO content of the hollow silica particles. ２ The sol according to claim 1 or claim 2, wherein the amount is 0.001 to 10% by mass.

5. The sol according to claim 1 or claim 2, wherein the average particle size of the hollow silica particles measured by dynamic light scattering is 20 to 150 nm.

6. The above hollow silica particles SiO ２ The sol according to claim 1 or claim 2, wherein the surface charge amount converted to 1 g is 5 to 250 μeq / g.

7. The sol according to claim 1 or claim 2, wherein the organic solvent is an alcohol, ketone, ether, or ester having 1 to 10 carbon atoms.

8. The above hollow silica particles are further expressed by formulas (1), (2), and (3): 【Chemistry 1】 (In formula (1), R １ Each of these represents an organic group having an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, or a cyano group, and is bonded to a silicon atom by a Si-C bond, R ２ Each of the following represents an alkoxy group, an acyloxy group, or a halogen group, and a is an integer from 1 to 3. In equations (2) and (3), R ３ and R ５ Each of these represents an alkyl group having 1 to 3 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and is bonded to a silicon atom by a Si-C bond, R ４ and R ６ (wherein 'b' represents an alkoxy group, an acyloxy group, or a halogen group, Y represents an alkylene group, an NH group, or an oxygen atom, b is an integer from 1 to 3, c is an integer of 0 or 1, and d is an integer from 1 to 3.) The sol according to claim 1 or claim 2, which is coated with at least one silane compound selected from the group consisting of silane compounds represented by .

9. A film-forming composition comprising the sol according to claim 1 or claim 2 and an organic resin.

10. A film obtained from the coating composition according to claim 9, wherein the visible light transmittance is 80% or more.

11. The following steps (A) to (C): (A) Step: Step to prepare a hollow silica aqueous sol, Step (B): At least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines having a water solubility of 80 g / L or more and having 1 to 10 carbon atoms is added to the hollow silica aqueous sol in step (A) in a proportion of 0.001 to 10% by mass based on SiO ２ of the hollow silica particles, A method for producing a sol according to claim 1 or claim 2, comprising the step of (C) replacing the aqueous medium of the aqueous sol of hollow silica particles obtained in step (B) with an alcohol, ketone, ether, or ester having 1 to 10 carbon atoms.

12. A method for producing a sol according to claim 11, further comprising step (D) of adding at least one silane compound selected from the group consisting of formulas (1), (2), and (3) after the completion of step (C) above, and heating.

13. The method for producing a sol according to claim 11, wherein step (C) above is a step of solvent substitution of the aqueous medium with an alcohol having 1 to 10 carbon atoms, and then further solvent substitution of the aqueous medium with a ketone, ether, or ester having 1 to 10 carbon atoms.

14. Step (C) is a step of solvent replacement of the aqueous medium with an alcohol having 1 to 10 carbon atoms, and step (D) is formula (1), formula (2), and formula (3): 【Chemistry 2】 (In formula (1), R1 represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, or a cyano group, and is bonded to a silicon atom by a Si-C bond; R2 represents an alkoxy group, an acyloxy group, or a halogen group; and a is an integer from 1 to 3.) In formulas (2) and (3), R3 and R5 each represent an alkyl group having 1 to 3 carbon atoms, or an aryl group having 6 to 30 carbon atoms, bonded to a silicon atom by a Si-C bond; R4 and R6 each 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 from 1 to 3; c is an integer of 0 or 1; and d is an integer from 1 to 3. A method for producing a sol according to claim 12, comprising the steps of adding at least one silane compound selected from the group consisting of silane compounds represented by , heating, and then further replacing the alcohol solvent with a ketone, ether, or ester having 1 to 10 carbon atoms.

15. A method for adjusting the surface charge of hollow silica particles using the manufacturing method described in claim 11.

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