Metal oxide particles, highly concentrated metal oxide sol, and methods for producing them

Abstract

To provide metal oxide particles that are capable of being highly concentrated in an organic solvent acting as a dispersion medium of a metal oxide sol, and also capable of being redispersed in the organic solvent, as well as a metal oxide sol containing the metal oxide particles and methods for producing them.SOLUTION: The present invention provides metal oxide particles that are surface-coated with a hydrolysate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2), and a hydrolysate of a silane compound (B) having three chemical groups (b1) and one hydrolyzable group (b2), wherein the metal oxide particles contain a basic compound (I), and the metal oxide particles have a particle refractive index of 1.4 to 3.0 and are dispersible in an organic solvent at 40 mass% or more in terms of metal oxide concentration, or have a particle refractive index of 1.1 to less than 1.4 and are dispersible in an organic solvent at 25 mass% or more in terms of metal oxide concentration.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to metal oxide particles such as surface-modified (also referred to as surface-coated) silica particles, highly concentrated metal oxide sols such as highly concentrated silica sols using the same, and methods for producing them.

Background Art

[0002] A dispersion (sol) of colloidal metal oxide particles, for example, silica sol, is a liquid in which silica particles are dispersed in a liquid medium. However, silica particles (silica powder) can be obtained by removing the liquid that is the dispersion medium. These metal oxide particles, when used as particulate metal oxide powders, have a sufficiently low volume ratio compared to when used as metal oxide sols, resulting in low transportation costs. Also, when regarded as an additive component in scenarios where metal oxides are used, there is no process for removing the dispersion medium after addition, which offers advantages in process management.

[0003] Regarding films containing metal oxide particles as additive components, attempts have been made to improve abrasion resistance, refractive index adjustment, heat resistance, heat insulation, electrical insulation resistance, dielectric properties, etc. by utilizing the properties of the metal oxides.

[0004] In films formed on a substrate together with an organic component and containing a metal oxide as these additive components, during the manufacturing process that includes a process of removing all or part of the film thereafter, the organic component can often be removed using chemical etching or gas etching, but the metal oxide particles have high etching resistance and are difficult to remove.

[0005] Redispersible nanoparticles obtained by adding a surface modifier containing a functional group selected from thiol, sulfide, disulfite, or polysulfide to a nanoparticle dispersion and subjecting it to radical polymerization together with an organic monomer are disclosed (see Patent Document 1).

[0006] A method for producing surface-modified silica particles having an average particle diameter of 100 nm or less, comprising: a) providing a preliminary dispersion; b) subjecting the preliminary dispersion to high-pressure pulverization to form a dispersion; and c) removing the liquid phase of the dispersion, the surface-modified silicon dioxide particles being redispersible and coated with a silylamine. Silica particles used for toner powder, silicone rubber, adhesives, and abrasion-resistant surface coatings are disclosed (see Patent Document 2).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide metal oxide particles that can be concentrated at a high concentration in an organic solvent that is a dispersion medium of a metal oxide sol and can be redispersed in the organic solvent, a metal oxide sol containing the metal oxide particles, and a method for producing the same.

Means for Solving the Problems

[0009] In a first aspect, the present invention provides metal oxide particles having a hydrolyzate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2) and a hydrolyzate of a silane compound (B) having three chemical groups (b1) and one hydrolyzable group (b2) on the surface, wherein the silane compound (A) has the following formula (1):

[0010]

Chemical Formula

[0011] (In formula (1), R 1is a chemical group (a1), which is at least one chemical group selected from the group consisting of a linear or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and a (meth)acryloxy group-containing alkyl group, and is bonded to a silicon atom by an Si-C bond, R 2 is a hydrolyzable group (a2), which is at least one hydrolyzable group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 2 to 10 carbon atoms, and a halogen group. ) is at least one silane compound selected from the group of silane compounds represented by the silane compound (B) is the following formula (2) and the following formula (3):

[0012] [Chemical formula]

[0013] (In formula (2) and formula (3), R 3 and R 4 are chemical groups (b1), which are alkyl groups having 1 to 3 carbon atoms or aryl groups having 6 to 30 carbon atoms and are bonded to a silicon atom by an Si-C bond, R 5 and Y are hydrolyzable groups (b2), which each represent an alkoxy group, an acyloxy group, or a halogen atom, and Y represents an NH group or an oxygen atom. ) is at least one silane compound selected from the group of silane compounds represented by the above metal oxide particles contain a basic compound (I), and the metal oxide particles have a particle refractive index of 1.4 to 3.0 and can be dispersed in an organic solvent at a metal oxide concentration of 40% by mass or more, or the metal oxide particles have a particle refractive index of less than 1.1 to 1.4 and can be dispersed in an organic solvent at a metal oxide concentration of 25% by mass or more. The above metal oxide particles As a second aspect, the metal oxide particles have an average primary particle diameter of 5 to 120 nm, and the metal component is composed of an oxide of at least one metal component selected from the group consisting of silicon, a metal element in the fourth period of the periodic table, and a metal element in the fifth period of the periodic table. The metal oxide particles according to claim 1 As a third aspect, the metal oxide particles have an average primary particle diameter of 5 to 120 nm, and the metal component is an oxide of at least one metal component selected from the group consisting of silicon, titanium, tin, cobalt, nickel, zirconium, antimony, cerium, magnesium, calcium, strontium, iron, and aluminum. The metal oxide particles described in the first aspect, As a fourth aspect, on the surface of the silica particles, further as a silane compound (C), the following formula (4):

[0014]

Chemical formula

[0015] (In formula (4), R 6 is a chemical group (c1), each of which is at least one chemical group selected from the group consisting of a linear or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, and a (meth)acryloxy group-containing alkyl group, and is bonded to a silicon atom by an Si-C bond. R 7 is a hydrolyzable group (c2), each of which is at least one hydrolyzable group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 2 to 10 carbon atoms, and a halogen group.) The metal oxide particles according to any one of the first to third aspects, which are coated with a hydrolyzate of at least one silane compound selected from the group of silane compounds represented by As a fifth aspect, in the measurement of Si-NMR of the silane compound on the surface of the metal oxide particles, the content ratio of each of the M structure, D structure, and T structure is such that when the total of the M structure, D structure, and T structure is 100 mol%, the M structure is 30 mol% or more and less than 60 mol%, the D structure is 30 mol% or more and less than 90 mol%, and the T structure is 0 mol% or more and less than 30 mol%. The metal oxide particles according to any one of the first to fourth aspects, 29 As a sixth aspect, the metal oxide particles according to any one of the first to fifth aspects, having a degree of hydrophobicity of 20 to 80 volume% by the methanol titration method, ​As a seventh aspect, the metal oxide particles described in the first to sixth aspects, having a degree of hydrophobicity by methanol titration method of 20% by volume or more and less than 60% by volume, As an eighth aspect, the metal oxide particles described in the first aspect, in which, by measurement by a leaching method, aluminum atoms are bonded to the surface of the metal oxide particles at a ratio (A) of 20 to 20,000 ppm / aluminum oxide per 1 g of the metal oxide in terms of Al2O3, As a ninth aspect, the metal oxide particles described in the eighth aspect, wherein the leaching method calculates the ratio (A) of the compound containing aluminum atoms bonded to the surface of the metal oxide particles leached with an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, per 1 g of the metal oxide of the metal oxide particles in terms of Al2O3, As a tenth aspect, in the measurement by a dissolution method using an aqueous hydrofluoric acid solution, aluminum atoms present in the entire metal oxide particles are bonded at a ratio (B) of 50 to 50,000 ppm / aluminum oxide per 1 g of the metal oxide in terms of Al2O3, and the value obtained by dividing the ratio (A) by the ratio (B) is 0.001 to 1.0, the metal oxide particles described in the eighth or ninth aspect, As an eleventh aspect, the metal oxide particles described in any one of the first to tenth aspects, wherein the basic compound (I) is an amine, an alkali metal hydroxide, an alkoxide compound of an alkali metal, ammonia, or a quaternary ammonium hydroxide, As a twelfth aspect, the metal oxide particles described in any one of the first to eleventh aspects, wherein the metal oxide particles are solid metal oxide particles having no space inside the particles, hollow metal oxide particles having a space inside the outer shell, or mixed metal oxide particles of these particles, As a thirteenth aspect, a metal oxide sol in which the metal oxide particles described in any one of the first to twelfth aspects are dispersed in an organic solvent and / or a reactive monomer, As a fourteenth aspect, the metal oxide sol described in the thirteenth aspect, wherein the dynamic light scattering method average particle diameter of the metal oxide particles in the metal oxide sol is 5 to 240 nm, As a 15th aspect, the metal oxide sol according to the 13th or 14th aspect, wherein the organic solvent is alcohol, ketone, ether, ester, amide, glycol, or hydrocarbon, As a 16th aspect, the metal oxide sol according to any one of the 13th to 15th aspects, wherein the reactive monomer is an acrylic compound, an allyl compound, an isocyanate compound, an isothiocyanate compound, an epoxy compound, a diamine-containing compound, a diol-containing compound, a dicarboxylic acid-containing compound, a disulfonyl chloride-containing compound, a dithiol-containing compound, a disulfide-containing compound, a divinyl-containing compound, a diallyl-containing compound, styrene, a tetracarboxylic acid anhydride, a bismaleimide, a vinyl-containing compound, a lactone ring-containing compound , a lactide-containing compound, a fluorine-containing compound, a cyclic olefin-containing compound, ethylene, propylene, or a silane. As a 17th aspect, regarding the average particle diameter (nm) of the metal oxide particles in the metal oxide sol by the dynamic light scattering method in the dispersion solvent when redispersed in an organic solvent after drying under the drying conditions of 60°C to 100°C and 50 Torr for the metal oxide sol according to any one of the 13th to 16th aspects, a metal oxide sol in which the ratio of (dynamic light scattering method average particle diameter after redispersion) / (dynamic light scattering method average particle diameter before redispersion) is 0.6 to 3.0. As an 18th aspect, regarding the average particle diameter (nm) of the metal oxide particles in the metal oxide sol by the dynamic light scattering method in the metal oxide sol after storing the metal oxide sol according to any one of the 13th to 17th aspects at 50°C for 4 weeks, a metal oxide sol in which the ratio of (dynamic light scattering method average particle diameter after storing at 50°C) / (dynamic light scattering method average particle diameter before storing at 50°C) is 0.8 to 2.0. As a 19th aspect, metal oxide particles having a refractive index of 1.4 to 3.0, wherein the ratio of (EMS viscosity of the redispersed metal oxide sol) / (EMS viscosity of the dispersion medium) is 1 to 3000 in terms of the EMS viscosity (mPa·s) of the metal oxide sol obtained by redispersing the metal oxide particles at a metal oxide concentration of 60% by mass in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20°C, and the dispersion medium is an organic solvent or a reactive monomer. As a 20th aspect, metal oxide particles having a refractive index of 1.1 to 1.4, wherein the ratio of (the EMS viscosity of the redispersed metal oxide sol) / (the EMS viscosity of the dispersion medium) is 1 to 3000 in terms of the EMS viscosity (mPa·s) of a metal oxide sol obtained by redispersing the metal oxide particles at a metal oxide concentration of 30% by mass in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20°C. As a 21st aspect, a metal oxide sol containing the metal oxide particles and the dispersion medium according to the 19th or 20th aspect, wherein the metal oxide particles include metal oxide particles A having an average primary particle diameter of 35 to 200 nm and metal oxide particles B having an average primary particle diameter of 5 to 100 nm, the ratio of (the average primary particle diameter of the metal oxide particles A) / (the average primary particle diameter of the metal oxide particles B) is less than 1.1 to 20, and the ratio of (the EMS viscosity of the metal oxide sol) / (the EMS viscosity of the dispersion medium) is 1 to 1000. As a 22nd aspect, a dispersion varnish composition containing the metal oxide particles according to any one of the 1st to 12th aspects and an organic component. As a 23rd aspect, the dispersion varnish composition according to the 22nd aspect, wherein the organic component contains at least one monomer selected from acrylic compounds, allyl compounds, isocyanate compounds, isothiocyanate compounds, epoxy compounds, diamine-containing compounds, diol-containing compounds, dicarboxylic acid-containing compounds, disulfonyl chloride-containing compounds, dithiol-containing compounds, disulfide-containing compounds, divinyl-containing compounds, diallyl-containing compounds, styrene, tetracarboxylic acid anhydrides, bismaleimides, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, propylene, or silanes, or a polymer containing these components. As a 24th aspect, a composite composition containing the metal oxide particles according to any one of the 1st to 12th aspects and an organic resin material or a polysiloxane-based resin. As a 25th aspect, the organic resin material is at least one selected from the group consisting of styrene resins, epoxy resins, thioepoxy resins, novolak resins, cyanate resins, phenol resins, acrylic resins, maleimide resins, polyester resins, urethane resins, polyurea resins, polyimide resins, polyamide resins, polyamic acid resins, polyhydroxyimide resins, polybenzoxazole resins, polybenzimidazole resins, polybenzothiazole resins, polyhydroxyamide resins, polyhydroxyazomethine resins, polyether resins, polybenzoxazine resins, polytetrafluoroethylene resins, cycloolefin polymer resins, unsaturated polyester resins, vinyltriazine resins, polyphenylene sulfide resins, crosslinkable polyphenylene oxide resins, and curable polyphenylene ether resins. The composite composition according to the 24th aspect, which is at least one selected from the group consisting of and condensation resins. As a 26th aspect, the dispersion varnish composition is used for semiconductor device materials, semiconductor element materials, semiconductor resist materials, nanoimprinting, insulating film materials, copper-clad laminate materials, printed circuit board materials, printed board materials, printing ink materials, pigments, paints, sealant materials, hard coat materials, 3D printing materials, antireflection film materials, structural color forming members, in-vehicle component materials, electronic component materials, mechanical element components, adhesive materials, battery materials, power generation materials, chargeability imparting materials, conductivity imparting materials, powder fluidity imparting materials, cosmetic materials, flexible wiring materials, liquid crystal display materials, organic EL display materials, micro LED display materials, QD-EL display materials, flexible display materials, antenna materials, optical wiring materials, or sensing materials, which is the dispersion varnish composition according to the 22nd aspect or the 23rd aspect. As a 27th aspect, the composite composition is the composite composition according to the 24th or 25th aspect, which is used for a semiconductor device material, a material for a semiconductor element, a material for a semiconductor resist, nanoimprint, a material for an insulating film, a material for a copper-clad laminate, a material for a printed circuit board, a material for a printed board, a material for a printing ink, a pigment, a paint, a material for a sealant, a material for a hard coat, a 3D printing material, a material for an antireflection film, a structural color forming member, a material for in-vehicle parts, a material for electronic parts, a mechanical element part, a material for an adhesive, a material for a battery, a material for power generation, a charge imparting material, a conductivity imparting material, a powder fluidity imparting material, a cosmetic material, a flexible wiring material, a material for a liquid crystal display, a material for an organic EL display, a material for a micro LED display, a material for a QD-EL display, a flexible display material, an antenna material, an optical wiring material, or a sensing material. As a 28th aspect, the following steps (A) to (C): (A) step: A step (A) of preparing a metal oxide sol in which metal oxide particles having an average primary particle diameter of 5 to 120 nm are dispersed in an alcohol having 1 to 5 carbon atoms. (B) step: A step of adding a silane compound (A) described in formula (1), a silane compound (B) selected from the group consisting of formula (2) and formula (3), and a basic compound (I) to the metal oxide sol obtained in step (A). (C) step: A step of drying the metal oxide sol obtained in step (B), which is a method for producing metal oxide particles according to any one of the 1st to 12th aspects. As a 29th aspect, among the steps (A) to (C) described in the 27th aspect, whether step (C) is the following step (C’), or the following step (D) is further added to the above steps (A) to (C): (C’) step: A step of solvent substitution of the metal oxide sol obtained in step (B) with an organic solvent other than an alcohol having 1 to 5 carbon atoms. (D) step: A step of dispersing the metal oxide particles obtained in step (C) in an organic solvent, which is a method for producing a metal oxide sol according to any one of the 14th to 22nd aspects, and As a 30th aspect, the following steps (E) to (G): (E) Step: A step of adding water to a dispersion in which metal oxide particles are dispersed in an organic solvent, (F) Step: A step of removing the supernatant solvent after the (E) step to obtain a precipitate, (G) Step: A step of drying the precipitate after the (F) step to obtain metal oxide particle powder, which is a method for producing metal oxide particles according to any one of the first to twelfth aspects.

Advantages of the Invention

[0016] A colloidal metal oxide particle dispersion (sol), for example, silica sol, is a liquid in which silica particles are dispersed in a liquid medium. However, silica particles (silica powder) can be obtained by removing the liquid that is the dispersion medium. When these metal oxide particles are used as particulate metal oxide powder, the volume ratio is sufficiently low compared to when used as a metal oxide sol, the transportation cost is low, and when regarded as an additive component in a scenario where a metal oxide is used, there is no step of removing the dispersion medium after addition, which has advantages in process management.

[0017] In the present invention, since the powdered metal oxide particles can be redispersed in a solvent to a colloidal dispersion state before being powdered, a great advantage can be obtained in terms of transportation cost. Also, it is possible to use the metal oxide particles in a highly concentrated state before powdering, which has great advantages not only in terms of transportation cost but also in reducing the burden of removing the solvent after addition.

[0018] When considered as an additive component, a film containing metal oxide particles has advantages in terms of wear resistance, refractive index adjustment, heat resistance, heat insulation, electrical insulation resistance, dielectric properties, etc. by utilizing the properties of the metal oxide.

[0019] In a film formed on a substrate together with an organic component and containing a metal oxide as these additive components, in a manufacturing process that includes a process of removing all or part of the film thereafter, often the organic component can be removed using chemical etching or gas etching, but the metal oxide particles have high etching resistance and are difficult to remove.

[0020] When removing these metal oxide particles together with the film from the substrate, it is possible to remove them with a chemical solution (for example, a chemical solution using an organic solvent as a wet etching solution). The removed metal oxide particles are a dispersion (sol) dispersed in an organic solvent, and since it is useful in the process that the chemical solution used for removal is removed in a small amount, it is desirable to be able to form a highly concentrated sol. In the present invention, when the metal oxide particles contained in the film are removed with a chemical solution such as an organic solvent, it is possible to provide metal oxide particles that can be removed even with a small amount of a chemical solution such as an organic solvent.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0022] The present invention relates to metal oxide particles surface-coated with a hydrolyzate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2) and a hydrolyzate of a silane compound (B) having three chemical groups (b1) and one hydrolyzable group (b2), wherein the silane compound (A) is at least one silane compound selected from the group of silane compounds represented by the above formula (1), the silane compound (B) is at least one silane compound selected from the group of silane compounds represented by the above formula (2) and the above formula (3), the above metal oxide particles contain a basic compound (I), the metal oxide particles have a particle refractive index of 1.4 to 3.0 and can be dispersed in an organic solvent at a metal oxide concentration of 40% by mass or more, or 40 to 90% by mass, or 50 to 90% by mass, or 60 to 90% by mass or more, or the metal oxide particles have a particle refractive index of less than 1.1 to 1.4 and can be dispersed in an organic solvent at a metal oxide concentration of 25% by mass or more, or 30% by mass or more, or 25 to 60% by mass, or 30 to 60% or more. The metal oxide particles used in the present invention can have an average primary particle diameter of 5 to 120 nm and can be metal oxide particles selected from the group consisting of at least one metal component selected from silicon, a metal element in the fourth period of the periodic table, and a metal element in the fifth period of the periodic table.

[0023] Examples of the metal component in the fourth period include potassium, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, and the like.

[0024] Examples of the metal component in the fifth period include rubidium, strontium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, and the like.

[0025] The above metal oxide particles have an average primary particle diameter of 5 to 120 nm, and oxides of at least one metal component selected from the group consisting of silicon, titanium, tin, cobalt, nickel, zirconium, antimony, cerium, magnesium, calcium, strontium, iron, and aluminum can be used. In particular, silica particles in which the metal component is silicon can be used as the metal oxide particles.

[0026] The above metal oxide particles include single metal oxide particles or composite metal oxide particles. The composite metal oxide can be used as a solid solution of metal oxides, as composite colloid particles in which metal oxide particles have chemical bonds at the interface, or as a mixture of metal oxide particles.

[0027] As the metal oxide particles, solid metal oxide particles without space inside the particles, hollow metal oxide particles having a space inside the outer shell, or mixed metal oxide particles of these particles can be used. The solid metal oxide particles can be described as follows.

[0028] Examples of single metal oxide particles include silica particles (i.e., silicon oxide particles), titanium oxide particles, tin oxide particles, cobalt oxide particles, nickel oxide particles, zirconium oxide particles, magnesium oxide particles, and the like.

[0029] The solid metal oxide particles have an average primary particle diameter of 5 to 120 nm, or 10 to 100 nm, a particle refractive index of 1.4 to 3.0, and a surface silanol group density of 0.4 to 3.0 per nm 2 and are as follows.

[0030] The above solid metal oxide particles can be obtained as a solid metal oxide sol dispersed in a dispersion medium. A solid metal oxide sol in which solid metal oxide particles are dispersed in a dispersion medium and having an average particle diameter of 20 to 250 nm, or 20 to 150 nm by the dynamic light scattering method can be obtained.

[0031] The above-mentioned mesoporous metal oxide particles are redispersed in a dispersion medium with an EMS viscosity (mPa·s) of 1 to 20 at 20°C, and the EMS viscosity (mPa·s) of a metal oxide sol obtained by redispersing metal oxide particles with a refractive index of 1.4 to 3.0 at a metal oxide concentration of 60% by mass, and the ratio of (EMS viscosity of the redispersed metal oxide sol) / (EMS viscosity of the dispersion medium) can be 1 to 3000, 1 to 2000, 1 to 1000, 1 to 500, 1 to 100, 1 to 70, or 1 to 50. By setting the ratio of (EMS viscosity of the redispersed metal oxide sol) / (EMS viscosity of the dispersion medium) of the metal oxide particles to 1 to 3000, the fluidity of the metal oxide sol when redispersed in the dispersion medium becomes good.

[0032] The above-mentioned metal oxide particles can be a metal oxide sol containing metal oxide particles and a dispersion medium. The metal oxide particles include metal oxide particles A with an average primary particle diameter of 35 to 200 nm, or 50 nm to 200 nm, or 50 nm to 150 nm, or 60 nm to 100 nm, and metal oxide particles B with an average primary particle diameter of 5 to 100 nm, or 5 nm to 50 nm, or 10 nm to 35 nm and the ratio of (average primary particle diameter of metal oxide particles A) / (average primary particle diameter of metal oxide particles A) is less than 1.1 to 20, or less than 2 to 20, or 2 to 10, or 4 to 10, and the ratio of (EMS viscosity of the metal oxide sol) / (EMS viscosity of the dispersion medium) is 1 to 1000, or 1 to 100, or 1 to 10, or 1.1 to 10, which can be a metal oxide sol. By including metal oxide particles A with an average primary particle diameter of 35 to 200 nm and metal oxide particles B with an average primary particle diameter of 5 to 100 nm, the bearing effect that small particles reduce the friction coefficient of large particles occurs, the fluidity of metal oxide particles A in the metal oxide sol is improved, and the EMS viscosity of the metal oxide sol can be reduced.

[0033] The above metal oxide particles can have at least two peaks in the average particle size distribution, and the largest peak a in the range of D50 to D90 is in the range of 35 to 200 nm, or 50 nm to 200 nm, or 50 nm to 150 nm, or 60 nm to 100 nm, and the largest peak b in the range of D10 to D50 can be in the range of 5 to 100 nm, or 5 nm to 50 nm, or 10 nm to 35 nm.

[0034] The above D10, D50, and D90 are the particle diameters indicating cumulative 10%, 50%, and 90% from the fine particle side showing the cumulative particle size distribution. In the present invention, for example, the values of the cumulative particle size distribution can be measured by the particle size distribution by image analysis. In the measurement of the particle size distribution by image analysis, the measurement sample is analyzed as a transmission electron microscope image. There are two methods for analyzing the D value: the number distribution method and the volume distribution method. In the number distribution method, the particle is regarded as a perfect circle with the same area as the area of the particle, and it is measured what percentage of particles having a specific particle diameter exist in a certain field of view. In the volume distribution method, assuming that the volume and weight are in a proportional relationship if the density of the particle is constant, it is measured what mass percentage of particles having a specific particle diameter exist in a certain amount of sample. In the present invention, it is preferable to obtain the D value (D10, D50, D90) by the volume distribution method.

[0035] The above metal oxide particles can include metal oxide particles having at least two peaks in the average particle size distribution. Here, as for at least two peaks, the fact that the largest peak a in the range of D50 to D90 exists in the range of 35 nm or more and 200 nm or less means that the largest peak exists in the range of D50 to D90 in the cumulative particle size distribution, and the fact that the largest peak b in the range of D10 to D50 exists in the range of 5 nm or more and less than 100 nm means that the largest peak exists in the range of D10 to D50 in the cumulative particle size distribution.

[0036] The volume ratio of the above metal oxide particles, (volume of metal oxide particles A) / (volume of metal oxide particles B), can be 0.1 to 100, or 0.1 to 50, or 0.1 to 20, or 1 to 10, or 2 to 10. The volumes of metal oxide particles A and metal oxide particles B can be calculated from the (average particle volume calculated from the average primary particle diameter) × (number of particles) of metal oxide particles A and metal oxide particles B in a transmission electron microscope image. By setting the ratio of (volume of metal oxide particles A) / (volume of metal oxide particles B) of the metal oxide particles to 0.1 to 100, the viscosity of the metal oxide sol containing the metal oxide particles can be sufficiently reduced to obtain a sol with good fluidity.

[0037] The above metal oxide particles can use solid silica particles having a particle refractive index of 1.4 to 3.0, 1.4 to 2.5, 1.4 to 2.0, or 1.4 to 1.7 and having no space inside the particles.

[0038] In addition, the above metal oxide particles can use hollow silica particles having a particle refractive index of 1.1 to less than 1.4, 1.1 to 1.35, 1.15 to 1.35, or 1.2 to 1.35 and having a space inside the outer shell.

[0039] The silica particles include colloidal silica particles obtained by heat-treating active silica obtained by cation-exchanging an aqueous solution of an alkali metal silicate, colloidal silica particles obtained by hydrolyzing an alkoxysilane in an organic solvent, fumed silica particles obtained by hydrolyzing silicon tetrachloride in the flame of an oxygen / hydrogen burner, wet-process silica obtained by neutralizing sodium silicate with an acidic substance to generate silica and then through filtration and drying, and pulverized silica obtained by dry-pulverizing silica powder.

[0040] Examples of the composite metal oxide particles include core-shell type metal oxide particles composed of a combination of core particles and shell particles. Examples of the core particles / shell particles include titanium oxide particles / tin oxide and silicon dioxide composite particles, titanium oxide and tin oxide composite particles / tin oxide and silicon dioxide composite particles, titanium oxide particles and zirconium oxide particles composite particles / tin oxide and silicon dioxide composite particles, titanium oxide particles, tin oxide particles and zirconium oxide particles composite particles / tin oxide and silicon dioxide composite particles, titanium oxide particles / antimony oxide particles, and titanium oxide and tin oxide composite particles / antimony oxide particles combinations. The above core-shell type metal oxide particles can be prepared by charging in the range of (shell metal oxide) / (core metal oxide) of 0.05 to 1.0, or 0.1 to 1.0, or 0.15 to 1.0 by mass ratio.

[0041] In the present invention, an intermediate layer exists between the core particles and the shell particles. The intermediate layer is metal oxide particles composed of at least one combination selected from the group consisting of zirconium oxide, silicon dioxide, aluminum oxide, tin oxide, zinc oxide, iron oxide, niobium oxide, tantalum oxide, antimony oxide, and tungsten oxide as the component (D), and can be prepared by charging in the range of (metal oxide other than the core) / (core metal oxide) of 0.05 to 1.0, or 0.1 to 1.0, or 0.15 to 1.0 by mass ratio. As the metal oxide particles, solid metal oxide particles without space inside the particles, hollow metal oxide particles having a space inside the outer shell, or mixed metal oxide particles of these particles can be used.

[0042] When using a core-shell structure, coating with a coating layer containing metal oxide particles having a metal oxide component or metal oxide content different from that of the metal oxide component of the core metal oxide means that when the components of the metal oxides of the core and the coating layer are different, or even if the components of the metal oxides of the core and the coating partially overlap, it includes the case where the blending ratio of the metal oxides is different. For example, taking the composite oxide (B1) of tin oxide - silicon dioxide contained in the metal oxide particles of the coating layer as an example, as the alkali stannate, sodium stannate or potassium stannate can be used, and preferably sodium stannate.

[0043] As the alkali silicate, lithium silicate, sodium silicate, or potassium silicate can be used.

[0044] The alkali stannate and the alkali silicate can be prepared as an aqueous solution containing silicon dioxide / tin oxide in a mass ratio of 0.1 to 5, and then the cations present in the aqueous solution are removed by a cation exchange resin for use. The alkali stannate and the alkali silicate are weighed so that the mass ratio of silicon dioxide / tin oxide is in the ratio of 0.1 to 5.0 and dissolved in water for preparation. The preferred solid content concentration of the aqueous solution is 1 to 12% by mass as (SnO2 + SiO2).

[0045] In the prepared aqueous solution, cations are removed using a cation exchange resin. As the cation exchange resin, a hydrogen - type strongly acidic cation exchange resin is preferred, and for cation exchange, a column filled with, for example, Amberlite (trade name) 120B can be used. By performing this cation exchange, the silicate component and the stannate component polymerize to form silicon dioxide - stannic oxide composite colloid particles having a primary particle diameter of 1 to 4 nm. can be formed. These silicon dioxide - stannic oxide composite colloid particles have poor stability and gelate within several hours when left standing. Therefore, after cation exchange, an amine compound is quickly added for stabilization, and it is necessary to obtain an aqueous sol of silicon dioxide - stannic oxide composite oxide colloid particles having a primary particle diameter of 1 to 4 nm, stabilized with an amine compound present in a molar ratio of 0.1 to 1.0 of M / (SnO2 + SiO2) (where M represents the amine compound) and a mass ratio of silicon dioxide / stannic oxide of 0.1 to 5.0. The resulting aqueous sol is 0.1 to 10% by mass as (SnO2 + SiO2).

[0046] For the stabilization of the silicon dioxide - stannic oxide composite colloid particles generated by the cation exchange, it is appropriate to add an amine compound in an amount such that the molar ratio of M / (SnO2 + SiO2) (where M represents an amine compound) is 0.1 to 1.0. Adding an amine compound with a molar ratio of M / (SnO2 + SiO2) less than 0.1 to 1.0 is not preferable because the stability is lost and gelation occurs after standing for several hours. Next, an aqueous sol of metal oxide colloid particles (A) used for the core having a primary particle diameter of 5 to 60 nm and an aqueous sol of silicon dioxide - stannic oxide composite oxide colloid particles (B1) having a primary particle diameter of 1 to 4 nm and stabilized with an amine compound having a molar ratio of M / (SnO2 + SiO2) (where M represents an amine compound) of 0.1 to 1.0 and a mass ratio of silicon dioxide / stannic oxide of 0.1 to 5.0 are mixed at a ratio such that the mass ratio of the silicon dioxide - stannic oxide composite oxide colloid particles (B1) to the metal oxide colloid particles (A) is (B1) / (A) of 0.05 to 0.50, whereby an aqueous sol of modified metal oxide colloid particles (C) in which the metal oxide colloid particles (A) are coated with the silicon dioxide - stannic oxide composite oxide colloid particles (B1) can be obtained. The solid content concentration of the aqueous sol of the metal oxide colloid particles (A) is 0.5 to 50% by mass, preferably 5 to 30% by mass.

[0047] As the aqueous sol of the metal oxide colloid particles (A), those with a pH of 5 to 11.5, preferably pH 7 to 11.5 can be used. The pH of the aqueous sol can be adjusted with an alkaline component as needed. Examples of the alkaline component used include alkali metal hydroxides such as lithium, sodium, and potassium, hydroxides of alkaline earth metals such as calcium, magnesium, and strontium, ammonia, alkylamines such as ethylamine, triethylamine, isopropylamine, and n - propylamine, aralkylamines such as benzylamine, alicyclic amines such as piperidine, alkanolamines such as monoethanolamine and triethanolamine, and quaternary ammonium hydroxides. The mixing of the aqueous sol of the metal oxide colloid particles (A) and the aqueous sol of the coating particles (B1) is preferably carried out under stirring. The mixing ratio of the silicon dioxide - stannic oxide composite oxide colloid particles (B1) to the metal oxide colloid particles (A) is preferably 0.05 to 0.50 in terms of mass ratio (B1) / (A). If it is less than 0.05, the coating of the metal oxide colloid particles (A) serving as nuclei by the silicon dioxide - stannic oxide composite oxide colloid particles (B1) cannot be sufficiently carried out, and a stable hydrophilic organic solvent - dispersed sol or a hydrophobic organic solvent - dispersed sol having a water solubility of 0.05 to 12% by mass cannot be obtained. Also, the mass ratio of 0.50 is sufficient, and exceeding 0.50 is not efficient.

[0048] The sol (A) and the sol (B1) can be mixed at a rate such that the solid content of the other sol added to the container is 22 to 1000 parts by mass per minute with respect to 100 parts by mass of the solid content of one sol loaded in the container. Next, cation exchange of the obtained aqueous sol of the modified metal oxide colloid particles (C) is carried out. It is preferable to use a hydrogen - type strongly acidic cation exchange resin for cation exchange. Next, to the obtained aqueous sol, an amine compound in an amount such that the molar ratio M / (SnO2 + SiO2) (where M represents the amine compound) is 0.001 to 0.08 with respect to the silicon dioxide - stannic oxide composite oxide colloid particles (B 1) is added. If the amount of the amine compound added is such that the molar ratio of M / (SnO2 + SiO2) is less than 0.001, the dispersion stability of the hydrophilic organic solvent - dispersed sol of the present invention becomes insufficient, which is not preferable. Also, when the molar ratio of M / (SnO2 + SiO2) exceeds 0.08, it may interfere with the bonding of the silane compound to be bonded to the particle surface of the modified metal oxide colloid particles (C).

[0049] Next, the aqueous medium of the obtained aqueous sol is replaced with a hydrophilic organic solvent. As a method for replacing the dispersion medium from water to a hydrophilic organic solvent, known methods can be used, such as an evaporation replacement method under normal pressure or reduced pressure, an ultrafiltration membrane method, a solvent extraction method, etc. In order to efficiently perform the solvent replacement, it is preferable to preliminarily concentrate the obtained aqueous sol so that the concentration of the modified metal oxide colloid particles (C) contained therein is in the range of 1 to 70% by mass, or 10 to 50% by mass. For the concentration of the sol, known methods such as the heat evaporation method and the ultrafiltration method can be used. The temperature of the sol during the solvent replacement is carried out in the range from room temperature to the boiling point of the hydrophilic solvent. The solvent replacement is carried out until the water content in the sol becomes less than 5% by mass. The solid content concentration of the obtained sol is 20 to 70% by mass as the total metal oxide concentration of the modified metal oxide colloid particles (C).

[0050] In the present invention, as the dispersion medium of the sol, an organic solvent such as alcohol, ketone, ether, ester, amide, glycol, or hydrocarbon can be used. Examples of the organic solvent include alcohols, esters, ketones, ethers, amides, esters, or hydrocarbons having 1 to 10 carbon atoms which may have an ether bond. Examples of the alcohol having 1 to 10 carbon atoms include methanol, ethanol, n-propanol, i-propanol, n-butanol, isobutanol, n-pentanol, ethylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and the like. Examples of the ketone include linear or cyclic aliphatic ketones having 3 to 30 carbon atoms, such as methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, diisopropyl ketone, diisobutyl ketone, methyl amyl ketone, cyclohexanone, and the like.

[0051] Examples of the ether include linear or cyclic aliphatic ethers having 3 to 30 carbon atoms, such as diethyl ether, tetrahydrofuran, and the like. Examples of the ester include linear or cyclic esters having 2 to 30 carbon atoms, such as ethyl acetate, n-butyl acetate, sec-butyl acetate, methoxybutyl acetate, amyl acetate, n-propyl acetate, isopropyl acetate, ethyl lactate, butyl lactate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, phenyl acetate, phenyl lactate, phenyl propionate, and the like. The amide is an aliphatic amide having 3 to 30 carbon atoms, and examples thereof include dimethylacetamide, dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone, and the like. Examples of the glycol include ethylene glycol, diethylene glycol, polypropylene glycol, and polyethylene glycol.

[0052] Examples of the hydrocarbon include linear or cyclic aliphatic or aromatic hydrocarbons having 6 to 30 carbon atoms, such as hexane, pentane, heptane, octane, nonane, decane, benzene, toluene, xylene, and the like.

[0053] In the present invention, as the basic compound (I), an amine, an alkali metal hydroxide, an alkali metal alkoxide compound, ammonia, or a quaternary ammonium hydroxide can be used. As the alkali metal hydroxide, hydroxides of lithium, sodium, and potassium can be used. As the alkali metal alkoxide compound, alcoholates of lithium, sodium, and potassium can be used. The amine used in the present invention can include a secondary amine or a tertiary amine having 5 to 35 total carbon atoms. These amines can be charged and produced in the range of pH 5 to 11.5, preferably pH 7 to 11.5. Examples of the secondary amine include ethyl n-propylamine, dimethanolamine, diethanolamine, ethyl isopropylamine, dipropylamine, diisopropylamine, ethyl butylamine, n-propyl butylamine, dibutylamine, ethyl pentylamine, n-propyl pentylamine, isopropyl pentylamine, dipentylamine, ethyl octylamine, i-propyl octylamine, butyl octylamine, dioctylamine, and the like.

[0054] Examples of the tertiary amine include triethylamine, ethyl di-n-propylamine, diethyl n-propylamine, tri-n-propylamine, triisopropylamine, ethyl dibutylamine, diethyl butylamine, isopropyl dibutylamine, diisopropyl ethylamine, diisopropyl butylamine, tributylamine, ethyl dipentylamine, diethyl pentylamine, tripentylamine, methyl dioctylamine, dimethyl octylamine, ethyl dioctylamine, diethyl octylamine, trioctylamine, benzyldibutylamine, diazabicycloundecene, and the like. Among the above amines, secondary amines and tertiary amines having an alkyl group with 6 to 35 carbon atoms in total are preferred, and examples thereof include diisopropylamine, tripentylamine, triisopropylamine, dimethyl octylamine, trioctylamine, and the like. In addition, the quaternary ammonium hydroxide is preferably a quaternary ammonium hydroxide having an alkyl group with 1 to 10 carbon atoms, and examples thereof include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, and the like.

[0055] The metal oxide particles are those in which, in the measurement by the leaching method, aluminum atoms are bonded to the surface of the metal oxide particles at a ratio (A) of 100 to 20,000 ppm / metal oxide in terms of the mass of the metal oxide in terms of Al2O3.

[0056] The leaching method calculates the ratio (A) of the compound containing aluminum atoms bonded to the surface of the metal oxide particles leached with an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, in terms of Al2O3, to the mass of the metal oxide of the metal oxide particles.

[0057] In the measurement by the dissolution method using an aqueous hydrofluoric acid solution (hydrofluoric acid), for the above metal oxide particles, the aluminum atoms present in the whole metal oxide particles are bonded at a ratio (B) of 50 to 50,000, or 120 to 50,000 ppm / SiO2 in terms of Al2O3 to the mass of the metal oxide, and the value obtained by dividing the ratio (A) by the ratio (B) is 0.001 to 1.0.

[0058] In the present invention, examples of the hollow metal oxide particles having a space inside the outer shell include hollow silica particles. The hollow silica particles have a silica outer shell and a space inside the outer shell. The hollow si lica is obtained by forming an outer shell mainly composed of silica on the surface of a part corresponding to a core called a so-called template in a dispersion medium and removing the part corresponding to the core.

[0059] In the present invention, for the metal oxide particles, by measuring the aluminum present on the surface of the metal oxide particles by a leaching method using an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, the aluminum atoms can be shown in terms of Al2O3. For example, when the metal oxide particles are silica particles, by measuring the aluminum present on the surface of the silica particles by a leaching method using an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, the aluminum atoms can be shown in terms of Al2O3. That is, the aluminum atoms are bonded to the silica particles at a ratio (A) of 100 to 20,000 ppm / SiO2, or 100 to 15,000 ppm / SiO2, 100 to 10,000 ppm / SiO2, or 200 to 5,000 ppm / SiO2, or 500 to 5,000 ppm / SiO2, or 800 to 3,000 ppm / SiO2 in terms of Al2O3 with respect to the mass of SiO2 of the hollow silica particles on the surface of the hollow silica particles measured by the leaching method. The presence of aluminosilicate sites on the surface of the silica particles is important for dispersion in solvents and resins.

[0060] The aluminum atoms present as aluminosilicate on the surface of the metal oxide particles can be leached (eluted) in an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid with a structure close to that of an aluminum salt, aluminum oxide, or aluminum hydroxide, and the aluminum atoms can be measured from the solution using an ICP emission spectrometer and expressed in terms of Al2O3. In particular, a method of leaching (eluting) using an aqueous nitric acid solution is used. The aqueous nitric acid solution used for leaching can be used in the range of pH 0.5 to 4.0, 0.5 to 3.0, 0.5 to 2.0, or 1.0 to 1.5 of the aqueous solution, and typically, an aqueous nitric acid solution with a pH of 1.0 can be used.

[0061] For example, when the metal oxide particles are silica particles, the aluminum atoms present as aluminosilicate on the surface of the silica particles are leached (eluted) in an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, such that the aluminum atoms have a structure close to that of an aluminum salt, aluminum oxide, or aluminum hydroxide. Then, the aluminum atoms can be measured from the solution using an ICP emission spectrometer and expressed in terms of Al2O3. In particular, a method of leaching (eluting) using an aqueous nitric acid solution is employed. The aqueous nitric acid solution used for leaching can have a pH of the aqueous solution in the range of 0.5 to 4.0, 0.5 to 3.0, 0.5 to 2.0, or 1.0 to 1.5, and typically, an aqueous nitric acid solution with a pH of 1.0 can be used. For example, 100 mL of the above aqueous nitric acid solution is added to 1 g of silica, and the mixture is held at a temperature of 20 to 70 °C, or 40 to 60 °C for 10 to 24 hours to elute the aluminum compound from the silica particle surface, which can then be used as an analytical sample.

[0062] In the present invention, the silica particle surface can be defined as the region from which the aluminum compound can be eluted by the above leaching. This is achieved by grinding silica gel obtained by evaporating the solvent from a silica sol and further drying it at 250 °C to form silica powder. Then, 20 mL of an aqueous nitric acid solution with a pH of 1.0 is added to 0.2 g of the silica powder, shaken well, held in a constant temperature bath at 50 °C for 17 hours, and then centrifuged and filtered. The aluminum content in the filtrate is measured using an ICP emission spectrometer, and the amount of aluminum (Al2O3 / SiO2) (ppm) bound to the silica particle surface is determined by dividing the aluminum content converted to Al2O3 by the mass of the silica powder.

[0063] Also, even when forming an aluminosilicate on the surface of silica particles, depending on the manufacturing method, aluminosilicate may be formed not only selectively on the surface but also inside the silica particles. The aluminum atoms present in the entire hollow silica particles including the surface and the inside are combined with the silica particles at a ratio (B) of 120 to 50000 ppm / SiO2, or 500 to 20000 ppm / SiO2, or 500 to 10000 ppm / SiO2, or 1000 to 5000 ppm / SiO2, or 1000 to 4000 ppm / SiO2 in terms of Al2O3 conversion with respect to the mass of SiO2 of the hollow silica particles. The ratio (A) / (B), which is the ratio of aluminum present on the surface of the silica particles to the entire silica particles, can be set in the range of 0.001 to 1.0, or 0.01 to 1.0, or 0.1 to 1.0, or 0.3 to 1.0, or 0.4 to 1.0. For the silica particles, the aluminum atoms present in the entire silica particles can be measured by a dissolution method with a hydrofluoric acid aqueous solution and shown in terms of Al2O3 conversion. That is, the aluminum atoms present as aluminosilicate in the entire silica particles can be dissolved with a hydrofluoric acid aqueous solution and then measured from the solution using an ICP emission spectroscopic analyzer, and the aluminum atoms present in the entire silica particles can be shown in terms of Al2O3 conversion.

[0064] Thus, when aluminosilicate sites are formed on the surface of the silica particles, the amount of negative charge per 1 g of SiO2 of the hollow silica particles present on the surface of the silica particles is measured in the range of 5 to 250 μeq / g, or 5 to 150 μeq / g, or 5 to 100 μeq / g, or 25 to 150 μeq / g, or 25 to 100 μeq / g. The hollow silica particles have an average primary particle size of 5 to 120 nm, or 10 to 100 nm, a particle refractive index of less than 1.1 to 1.4, a shell thickness of 3 to 12 nm, or 5 to 10 nm, and a surface silanol group density of 0.4 to 3.0 per nm 2 is.

[0065] The above hollow silica particles can be obtained as a hollow silica sol dispersed in a dispersion medium. A sol in which the hollow silica particles are dispersed in a dispersion medium, and a hollow silica sol having an average particle diameter of 20 to 250 nm, or 20 to 150 nm by the dynamic light scattering method can be obtained.

[0066] The above hollow silica particles can have a ratio of (EMS viscosity of the redispersed hollow silica sol) / (EMS viscosity of the dispersion medium) of 1 to 3000, 1 to 2500, 1 to 2000, 1 to 1000, 1 to 500, or 1 to 100 in terms of the EMS viscosity (mPa·s) of a hollow silica sol obtained by redispersing hollow silica particles having a refractive index of 1.1 to 1.4 in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20°C at a silica concentration of 30% by mass. By setting the ratio of (EMS viscosity of the redispersed hollow silica sol) / (EMS viscosity of the dispersion medium) of the hollow silica particles to 1 to 3000, the fluidity of the hollow silica sol when redispersed in the dispersion medium becomes good.

[0067] Hollow silica is obtained by forming a silica-based outer shell on the surface of a portion corresponding to a core called a so-called template in a dispersion medium and removing the portion corresponding to the core. In this state, it is a hollow silica aqueous sol. The metal oxide particles of the present invention can have a degree of hydrophobicity of 30 to 80% by volume, or 40 to 80% by volume, 50 to 80% by volume, more than 60% by volume to 80% by volume, 40 to 60% by volume, less than 30 to 60% by volume, 20% by volume or more and less than 60% by volume, or 30 to 50% by volume as determined by the methanol titration method.

[0068] The above hollow silica particles can contain the above basic compound (I) and can be dispersed in the above organic solvent.

[0069] The metal oxide particles of the present invention can use metal oxide particles having a surface coated with a hydrolyzate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2) and a hydrolyzate of a silane compound (B) having three chemical groups (b1) and one hydrolyzable group ( b2).

[0070] As the silane compound (A), at least one silane compound selected from the above formula (1) can be used. In formula (1), R 1 is a chemical group (a1), which is at least one chemical group selected from the group consisting of a linear or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and an alkyl group containing a (meth)acryloxy group, and is bonded to a silicon atom by an Si-C bond. R 2 is a hydrolyzable group (a2), which is at least one hydrolyzable group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 2 to 10 carbon atoms, and a halogen atom.

[0071] The above alkyl group is an alkyl group having 1 to 10 carbon atoms, such as methyl group, ethyl group, n-propyl group, i-propyl group, cyclopropyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group, 2,2-dimethyl-n-propyl group, 1-ethyl-n-propyl group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group, 2,2-dimethyl-n-butyl group, 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2-methyl-cyclopentyl group, 3-methyl-cyclopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclobutyl group, 3-ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1,2,3-trimethyl-cyclopropyl group, 2,2,Examples include 3-trimethyl-cyclopropyl group, 1-ethyl-2-methyl-cyclopropyl group, 2-ethyl-1-methyl-cyclopropyl group, 2-ethyl-2-methyl-cyclopropyl group, 2-ethyl-3-methyl-cyclopropyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc.

[0072] The above aryl group is an aryl group having 6 to 40 carbon atoms, and examples thereof include phenyl group, naphthyl group, anthracene group, pyrene group, etc. The above (meth)acryloyl group represents both acryloyl group and methacryloyl group. Examples of the organic group having a (meth)acryloyl group include 3-methacryloxypropyl group, 3-acryloxypropyl group, etc. R 2 is a hydrolyzable group (a2), and examples of the alkoxy group include alkoxy groups having 1 to 10 carbon atoms, such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, n-pentyloxy group, 1-methyl-n-butoxy group, 2-methyl-n-butoxy group, 3-methyl-n-butoxy group, 1,1-dimethyl-n-propoxy group, 1,2-dimethyl-n-propoxy group, 2,2-dimethyl-n-propoxy group, 1-ethyl-n-propoxy group, n-hexyloxy group, etc., but are not limited thereto.

[0073] The above acyloxy group is an acyloxy group having 2 to 10 carbon atoms, such as methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, i-propylcarbonyloxy group, n-butylcarbonyloxy group, i-butylcarbonyloxy group, s-butylcarbonyloxy group, t-butylcarbonyloxy group, n-pentylcarbonyloxy group, 1-methyl-n-butylcarbonyloxy group, 2-methyl-n-butylcarbonyloxy group, 3-methyl-n-butylcarbonyloxy group, 1,1-dimethyl-n-propylcarbonyloxy group, 1,2-dimethyl-n-propylcarbonyloxy group, 2,2-dimethyl-n-propylcarbonyloxy group, 1-ethyl-n-propylcarbonyloxy group, n-hexylcarbonyloxy group, 1-methyl-n-pentylcarbonyloxy group, 2-methyl-n-pentylcarbonyloxy group, etc., but not limited thereto.

[0074] Examples of the above halogen atom include fluorine, chlorine, bromine, iodine, etc. In the silane compound (A), R 1 Preferably has a combination of one saturated hydrocarbon group and one unsaturated hydrocarbon group respectively. Examples of these combinations include the combination of a methyl group and a phenyl group, the combination of a methyl group and a 3-methacryloxypropyl group, and the combination of a methyl group and a 3-acryloxypropyl group. Examples of these silane compounds include methylphenyldimethoxysilane, methylphenyldiethoxysilane, methylmethacryloxydimethoxysilane, methylmethacryloxydiethoxysilane, methylacryloxydimethoxysilane, methylacryloxydiethoxysilane, etc.

[0075] At least one silane compound selected from the group consisting of the above formula (2) and the above formula (3) can be used as the silane compound (B). In formula (2) and formula (3), R 3 and R 4is a chemical group (b1), each being an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms and bonded to a silicon atom by an Si-C bond, and R 5 and Y are hydrolyzable groups (b2), each being R 5 represents an alkoxy group, an acyloxy group, or a halogen atom, and Y represents an NH group or an oxygen atom. For these alkyl groups, alkoxy groups, acyloxy groups, and halogen atoms, the above examples can be used. The above R 3 and R 4 The chemical group (b1) is preferably an alkyl group having 1 to 3 carbon atoms, examples thereof include a methyl group, an ethyl group, and a propyl group, and a trimethylsilyl group can be preferably used. Examples of the above silane compound can be exemplified as follows.

[0076]

Chemical formula

[0077] In the present invention, the metal oxide particles can be further coated with a hydrolyzate of at least one silane compound selected from the above formula (4) as the silane compound (C). In formula (4), R 6 is a chemical group (c1), each being at least one chemical group selected from the group consisting of a linear or cyclic alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, and a (meth)acryloxy group-containing alkyl group, and is bonded to a silicon atom by an Si-C bond, and R 7 is a hydrolyzable group (c2), each being at least one hydrolyzable group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 2 to 10 carbon atoms, and a halogen atom. In addition to the above alkyl groups, the alkyl group having 1 to 20 carbon atoms is preferably an alkyl group having 8 to 12 carbon atoms, examples thereof include an octyl group, a nonyl group, and a decyl group. For example, octyltrimethoxysilane, nonyltrimethoxysilane, and decyltrimethoxysilane can be mentioned.

[0078] As the silane compound, the silane compound manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

[0079] On the surface of the silica particles, hydroxyl groups, for example, in the case of silica particles, silanol groups react with the above silane compound, and the surface of the silica particles is coated with the above silane compound by siloxane bonds. The reaction temperature can be in the range from 20°C to the boiling point of the dispersion medium, for example, it can be carried out in the range of 20°C to 100°C. The reaction time can be carried out for about 0.1 to 10 hours.

[0080] As the coating amount of the above silane compound on the surface of the silica particles, the number of silicon atoms in the silane compound is 0.1 atoms / nm 2 ~20.0 atoms / nm 2 or 0.1 atoms / nm 2 ~6.0 atoms / nm 2 or 0.5 atoms / nm 2 ~4.0 atoms / nm 2 1 atom / nm 2 ~3.0 atoms / nm 2 The silane compound corresponding to the coating amount can be added to the silica sol to coat the surface of the silica particles. Water is required for the hydrolysis of the above silane compound, but if it is a sol of an aqueous solvent, those aqueous solvents are used. When the aqueous medium is solvent-exchanged with an organic solvent, the water remaining in the solvent can be used. For example, water present in an amount of 0.01 to 5% by mass can be used. Also, the hydrolysis can be carried out with a catalyst or without a catalyst.

[0081] When carried out without a catalyst, it is the case where the surface of the metal oxide particles exists on the acidic side, for example, the case where the surface of the silica particles exists on the acidic side. When a catalyst is used, examples of the hydrolysis catalyst include metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases. It is like this. Examples of the metal chelate compound as a hydrolysis catalyst include triethoxy·mono(acetylacetonato)titanium, triethoxy·mono(acetylacetonato)zirconium, etc. Examples of the organic acid as a hydrolysis catalyst include acetic acid, oxalic acid, etc. Examples of the inorganic acid as a hydrolysis catalyst include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, etc. Examples of the organic base as a hydrolysis catalyst include pyridine, pyrrole, piperazine, quaternary ammonium salts. Examples of the inorganic base as a hydrolysis catalyst include ammonia, sodium hydroxide, potassium hydroxide.

[0082] Examples of the organic acid include at least one organic acid selected from the group consisting of divalent aliphatic carboxylic acids, aliphatic oxycarboxylic acids, amino acids, and chelating agents. The divalent aliphatic carboxylic acids are oxalic acid, malonic acid, and succinic acid. The aliphatic oxycarboxylic acids are glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid. The amino acids are glycine, alanine, valine, leucine, serine, and threonine. Examples of the chelating agents include ethylenediaminetetraacetic acid, L-aspartic acid-N,N-diacetic acid, and diethylenetriaminepentaacetic acid, etc. Examples of the organic acid salts include alkali metal salts, ammonium salts, and amine salts of the above organic acids. Examples of the alkali metals include sodium and potassium.

[0083] The metal oxide particles of the present invention are obtained by coating the hydrolysis products of the silane compound (A), the hydrolysis products of the silane compound (B), and the hydrolysis products of the silane compound (C), and the silane compound on the surface of the metal oxide particles 29The M structure (monofunctional, i.e., a structure derived from a silane compound having one hydrolyzable group bonded to a silicon atom and three chemical groups bonded to the silicon atom), the D structure (bifunctional, i.e., a structure derived from a silane compound having two hydrolyzable groups bonded to a silicon atom and two chemical groups bonded to the silicon atom), and the T structure (trifunctional, i.e., a structure derived from a silane compound having three hydrolyzable groups bonded to a silicon atom and one chemical group bonded to the silicon atom) can coat the silane compound at a ratio such that when the total of the M structure, the D structure, and the T structure is 100 mol%, each is M structure = 30 mol% or more and less than 60 mol%, D structure = 30 mol% or more and less than 90 mol%, and T structure = 0 mol% or more and less than 30 mol%.

[0084] The metal oxide particles can obtain a metal oxide particle sol dispersed in an organic solvent and / or a reactive monomer. The average particle diameter of the sol by the dynamic light scattering method can be set in the range of 5 to 250 nm, or 5 to 200 nm. The organic solvent can be selected from alcohol, ketone, ether, ester, amide, glycol, or hydrocarbon. These organic solvents can use the above examples. The reactive monomer can be exemplified by acrylic compounds, allyl compounds, isocyanate compounds, isothiocyanate compounds, epoxy compounds, diamine-containing compounds, diol-containing compounds, dicarboxylic acid-containing compounds, disulfonyl chloride-containing compounds, dithiol-containing compounds, disulfide-containing compounds, divinyl-containing compounds, diallyl-containing compounds, styrene, tetracarboxylic acid anhydrides, bismaleimides, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, propylene, or silanes. The reactive monomer can itself be the dispersion medium of the sol, but when it is solid, gaseous, or highly viscous, it can be made the dispersion medium of the sol by mixing with an organic solvent. Examples of acrylic compounds include monomers such as acrylic acid, acrylamide, N,N-dimethylacrylamide, N-(2-hydroxyethyl)acrylamide, diacetoneacrylamide, 2-(dimethylamino)ethyl methacrylate, N-isopropylacrylamide, N,N-diethylacrylamide, 4-tert-butylcyclohexyl acrylate, N-[3-(dimethylamino)propyl]acrylamide, 4-acryloylmorpholine, tetrahydrofurfuryl acrylate, glycol methacrylate, or methacrylic acid. Examples of allyl compounds include allyl alcohol, allyl chloride, allyl ether, allyl glycidyl ether, allyl carboxylic acid, allyl amine, allyl isopropylacetyl urea, allylic acid, etc.

[0085] Examples of isocyanate compounds include aromatic isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, triphenylmethane triisocyanate, tris(isocyanatophenyl) thiophosphate, p-phenylene diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexyl, dicyclohexylmethane diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate. Examples of isothiocyanates include allyl isothiocyanate, sulforaphane, benzyl isothiocyanate, p-hydroxybenzyl isothiocyanate, gebalin, ipyrene, phenethyl isothiocyanate, etc.

[0086] Examples of epoxy compounds include 1,4-butanediol diglycidyl ether, 1,2-epoxy-4-(epoxyethyl)cyclohexane, glycerol triglycidyl ether, diethylene glycol diglycidyl ether, 2,6-diglycidylphenyl glycidyl ether, 1,1,3-tris[p-(2,3-epoxypropoxy)phenyl]propane, 1,2-cyclohexanedicarboxylic acid diglycidyl ester, 4,4'-methylenebis(N,N-diglycidylaniline), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, trimethylolethane triglycidyl ether, triglycidyl-p-aminophenol, tetraglycidyl metaxylenediamine, tetraglycidyl diaminodiphenylmethane, tetraglycidyl-1,3-bis(aminomethyl)cyclohexane, bisphenol-A-diglycidyl ether, bisphenol-F-diglycidyl ether, bisphenol-S-diglycidyl ether, pentaerythritol tetraglycidyl ether, resorcinol diglycidyl ether, phthalic acid diglycidyl ester, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, tetrabromobisphenol-A-diglycidyl ether, bisphenol hexafluoroacetone diglycidyl ether, pentaerythritol diglycidyl ether, hydrogenated bisphenol-A-diglycidyl ether, tris-(2,3-epoxypropyl)isocyanurate, 1-{2,3-di(propionyloxy)}-3,5-bis(2,3-epoxypropyl)-1,3,5-triazine-2,4,6·(1H,3H,5H)-trione, 1,3-bis{2,3-di(propionyloxy)}-5-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6·(1H,3H,5H)-trione, monoallyl diglycidyl isocyanurate, diglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, 1,4-bis(2,3-epoxypropoxy perfluoroisopropyl)cyclohexane, sorbitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcin diglycidyl ether, 1,6 - hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, phenyl glycidyl ether, p - tertiary butylphenyl glycidyl ether, adipic acid diglycidyl ether, o - phthalic acid diglycidyl ether, dibromophenyl glycidyl ether, 1,2,7,8 - diepoxyoctane, 1,6 - dimethylolperfluorohexane diglycidyl ether, 4,4’ - bis(2,3 - epoxypropoxyperfluoroisopropyl) diphenyl ether, 2,2 - bis(4 - glycidyloxyphenyl) propane, 3,4 - epoxycyclohexylmethyl - 3’,4’ - epoxycyclohexanecarboxylate, 3,4 - epoxycyclohexyloxirane, 2 - (3,4 - epoxycyclohexyl) - 3’,4’ - epoxy - 1,3 - dioxane - 5 - spirocyclohexane, 1,2 - ethylenedioxy - bis(3,4 - epoxycyclohexylmethane), 4’,5’ - epoxy - 2’, - methylcyclohexylmethyl - 4,5 - epoxy - 2 - methylcyclohexanecarboxylate, ethylene glycol - bis(3,4 - epoxycyclohexanecarboxylate), bis - (3,4 - epoxycyclohexylmethyl) adipate, and bis(2,3 - epoxycyclopentyl) ether can be mentioned. Also, bisphenol A liquid epoxy compound, bisphenol F liquid epoxy compound, or 3’,4’ - epoxycyclohexylmethyl 3’,4’ - epoxycyclohexanecarboxylate, tris(2,4 - epoxypropyl) isocyanurate, etc. can be mentioned.

[0087] Examples of diamine - containing compounds can include diamines such as ethylenediamine, putrescine, cadaverine, hexamethylenediamine, paraphenylenediamine, etc.

[0088] Examples of diol - containing compounds include 1,2 - propanediol, 1,3 - propanediol, 1,2 - butanediol, 1,3 - butanediol, 1,4 - butanediol, dipropylene glycol, glycerin, diglycerin, sorbitan, sorbitol, maltitol, glucose, sucrose, etc.

[0089] Examples of the dicarboxylic acid-containing compound include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, etc. Acid anhydrides thereof are also included, and examples thereof include acetic anhydride, propionic anhydride, oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, benzoic anhydride, etc.

[0090] Examples of the disulfonyl chloride-containing compound include 1,3-benzenedisulfonyl chloride.

[0091] Examples of the dithiol-containing compound include 2,3-dimercapto-1-propanol, sodium 2,3-dimercapto-1-propanesulfonate, 2,5-dimercapto-1,3,4-thiadiazole, etc.

[0092] Examples of the disulfide-containing compound include dimethyl disulfide, allyl disulfide, diphenyl disulfide, etc.

[0093] Examples of the divinyl-containing compound include divinylbenzene, etc.

[0094] Examples of the diallyl-containing compound include diallyldimethylammonium chloride, etc.

[0095] Styrene includes styrene-based compounds, and examples thereof include styrene, 3-acetoxy-5-hydroxystyrene, 4-acetoxystyrene, 3,5-bis(trifluoromethyl)styrene, p-bromostyrene, p-chlorostyrene, etc.

[0096] Examples of the tetracarboxylic acid anhydride include 3,3'-4,4'-biphenyltetracarboxylic dianhydride, 4,4'-biphthalic anhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, etc.

[0097] Examples of the bismaleimide include 4,4'-bismaleimidodiphenylmethane, phenylenebismaleimide, bisphenol A diphenyl ether bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, and the like.

[0098] Examples of the vinyl-containing compound include vinyl acetate, methyl vinyl ketone, vinyl chloride, vinylidene chloride, and the like.

[0099] Examples of the lactone ring-containing compound include beta-propiolactone, gamma-butyrolactone, delta-valerolactone, alpha-bulone, coumarin, and the like.

[0100] Examples of the lactide-containing compound include L-lactide, D-lactide, and the like.

[0101] Examples of the fluorine-containing compound include trifluoroethanol, 2,2,2-trifluoroethyl methacrylate, trifluoromethyltrimethylsilane, and the like.

[0102] Examples of the cyclic olefin-containing compound include cyclobutene, cyclopentene, cyclohexene, cycloheptene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, 1,5-cyclooctadiene, and the like.

[0103] Examples of the ethylene include ethylene-based compounds such as ethylene, propylene, butylene, and the like.

[0104] Examples of the silane include hydrolyzable silane compounds.

[0105] The above metal oxide particles and metal oxide sols can be produced by the following production method. The following steps (A) to (C): (A) Step: A step (A) of preparing a metal oxide sol in which metal oxide particles having an average primary particle diameter of 5 to 120 nm are dispersed in an alcohol having 1 to 5 carbon atoms. (B) Step: A step of adding a silane compound (A) described in formula (1), a silane compound (B) selected from the group consisting of formula (2) and formula (3), and a basic compound (I) to the metal oxide sol obtained in (A) step. (C) Step: A step of drying the metal oxide sol obtained in (B) step. It is obtained by a step including this.

[0106] And the metal oxide sol, whether (C) step is (C’) step, or further (D) step: (C’) Step: A step of solvent substitution of the metal oxide sol obtained in (B) step with an organic solvent other than an alcohol having 1 to 5 carbon atoms. (D) Step: A step of dispersing the metal oxide particles obtained in (C) step in an organic solvent. It may be obtained by a step including this.

[0107] Furthermore, the above metal oxide particles and metal oxide sol can also be produced by the following production method. The following (E) step to (G) step: (E) Step: A step of adding water to a dispersion in which metal oxide particles are dispersed in an organic solvent. (F) Step: A step of removing the supernatant solvent after (E) step to obtain a precipitate. (G) Step: A step of drying the precipitate after (F) step to obtain a metal oxide particle powder. It may be obtained by a step including this. Since the production method of the above (E) step to (G) step can remove most of the dispersion medium as the supernatant, the drying step can be significantly shortened.

[0108] Regarding the average particle diameter (nm) of the metal oxide particles in the metal oxide sol by the dynamic light scattering method in the dispersion solvent when the above metal oxide sol is redispersed in an organic solvent after drying under the drying conditions of 60°C to 100°C and 50 Torr, (dynamic light scattering method average particle diameter after redispersion) / (dynamic light scattering method average particle diameter before redispersion) The ratio is a metal oxide sol of 0.6 to 3.0. The drying conditions of 60°C to 100°C and 50 Torr may be any conditions that can remove the dispersion solvent contained in the metal oxide sol, and for example, 60°C 50 Torr, 80°C 50 Torr, etc. can be used. ​The metal oxide sol is such that the ratio of (dynamic light scattering average particle diameter after storage at 50°C) / (dynamic light scattering average particle diameter before storage at 50°C) of the average particle diameter (nm) of the metal oxide particles in the metal oxide sol by the dynamic light scattering method in the dispersion solvent after storing the metal oxide sol at 50°C for 4 weeks is 0.8 to 2.0.

[0109] In the present invention, a dispersion varnish composition containing metal oxide particles and an organic component is obtained. Examples of the organic components used herein include at least one monomer selected from acrylic compounds, allyl compounds, isocyanate compounds, isothiocyanate compounds, epoxy compounds, diamine-containing compounds, diol-containing compounds, dicarboxylic acid-containing compounds, disulfonyl chloride-containing compounds, dithiol-containing compounds, disulfide-containing compounds, divinyl-containing compounds, diallyl-containing compounds, styrene, tetracarboxylic acid anhydrides, bismaleimides, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, propylene, or silanes, or polymers containing these components. These organic components can include the above-mentioned components.

[0110] In the present invention, a composite composition containing the above metal oxide particles and an organic resin material or a polysiloxane-based resin is obtained.

[0111] At least one selected from the group consisting of organic resin materials such as styrene resins, epoxy resins, thioepoxy resins, novolak resins, cyanate resins, phenolic resins, acrylic resins, maleimide resins, polyester resins, urethane resins, polyurea resins, polyimide resins, polyamide resins, polyamic acid resins, polyhydroxyimide resins, polybenzoxazole resins, polybenzimidazole resins, polybenzothiazole resins, polyhydroxyamide resins, polyhydroxyazomethine resins, polyether resins, polybenzoxazine resins, polytetrafluoroethylene resins, cycloolefin polymer resins, unsaturated polyester resins, vinyltriazine resins, polyphenylene sulfide resins, crosslinkable polyphenylene oxide resins, curable polyphenylene ether resins, and condensation resins can be used. Examples of styrene resins include polystyrene, expanded polystyrene, AS resin (styrene-acrylonitrile copolymer), MS resin (styrene-methyl methacrylate copolymer), ABS resin (styrene-acrylonitrile-butadiene resin), and the like.

[0112] Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, aliphatic type epoxy resin, glycidylamine type epoxy resin, and the like.

[0113] As the thioepoxy resin, it is a polymer obtained using bis(2,3-epithiopropyl) sulfide, bis(2,3-epithiopropyl) disulfide, 1,3-bis(β-epithiopropylthio) cyclohexane, 1,4-bis(β-epithiopropylthio) cyclohexane, 1,3-bis(β-epithiopropylthiomethyl) cyclohexane, 1,4-bis(β-epithiopropylthiomethyl) cyclohexane, 2,5-bis(β-epithiopropylthiomethyl)-1,4-dithiane, 2,5-bis(β-epithiopropylthioethylthiomethyl)-1,4-dithiane, and 2-(2-β-epithiopropylthioethylthio)-1,3-bis(β-epithiopropylthio) propane, and can be obtained by copolymerizing a polyisocyanate compound or a polythiol compound.

[0114] Examples of the novolak resin include phenol novolak resin, bisphenol A type novolak resin, and cresol novolak resin.

[0115] Examples of the cyanate resin include cyanate ester resin produced from cyanate and bisphenol A.

[0116] Examples of the phenol resin include novolak resin obtained using phenol and formaldehyde as raw materials with an acid catalyst, and resol resin obtained using an alkali catalyst.

[0117] Examples of the acrylic resin include polymethyl methacrylate, polyacrylate ester copolymerized with methyl methacrylate, methyl methacrylate, and styrene, etc., sodium polyacrylate copolymerized with sodium acrylate, methyl acrylate, and vinyl acetate, etc., polyacrylonitrile copolymerized with acrylonitrile, methyl acrylate, and methyl methacrylate, etc., and polyacrylamide obtained by hydrolyzing acrylonitrile.

[0118] Examples of the maleimide resin include maleimide-modified epoxy resin, epoxy-modified bismaleimide resin, and thiol-modified bismaleimide resin.

[0119] Examples of polyester resins include aliphatic polyesters produced by polycondensation or ring-opening polymerization such as polycaprolactone (PCL), polylactic acid (PLA), polyhydroxybutyrate (PHB), polyglycolic acid (PGA), and polyethylene adipate (PEA), semi-aromatic polyesters produced by polycondensation such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polytrimethylene terephthalate (PTT), and aromatic polyesters produced by polycondensation such as polyester (LCP) of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid and polyester (PAR) of bisphenol A and phthalic acid.

[0120] Examples of urethane resins include acrylic urethane resins that combine a polyol as the main component and a polyisocyanate as the curing agent, with the acrylic polyol as the main component.

[0121] Examples of polyurea resins include resins produced by the reaction of isocyanate and polyamine.

[0122] Examples of polyimide resins include resins obtained by the reaction of carboxylic anhydride and diamine. Examples of condensation polymerization type polyimide include pyromellitic acid type polyimide resin, biphenyltetracarboxylic acid type polyimide resin, and benzophenonetetracarboxylic acid type polyimide resin. Examples of addition type polyimide include bismaleimide type polyimide resin, nadic acid terminal type polyimide resin, and acetylene terminal type polyimide resin.

[0123] Examples of polyamide resins include those using linear polymers with amide bonds, which may be synthesized by ring-opening polymerization of omega amino acids or by condensation polymerization of diamines and dicarboxylic acids, such as nylon with an aliphatic backbone and aramid with only an aromatic backbone.

[0124] As the polyamic acid resin, a polyamic acid as an intermediate polymer of an acid anhydride and a diamine for synthesizing a polyimide resin can be used. Examples of the polyhydroxyimide resin include photosensitive polyimide resins having a hydroxyamide group or a hydroxyimide group. Examples of the polybenzoxazole resin include thermosetting resins having a benzoxazole ring.

[0125] Examples of the polybenzimidazole resin include polybenzazoles containing benzimidazole as a repeating unit, such as polybenzoxazole and polybenzothiazole. Examples of the polyhydroxyazomethine resin include polyhydroxyazomethine resins having an azomethine as a linking site. Examples of the polyether-based resin include resins obtained by reacting diisocyanate with glycols or diamines, and engineering plastics such as polyetheretherketone (PEEK), polyetherketone (PEK), and polyethersulfone (PES).

[0126] Examples of the polybenzoxazine resin include resins formed by reacting phenol and bisphenol A with formaldehyde and an aromatic amine, and can be cured by, for example, thermal ring-opening polymerization. Examples of the polytetrafluoroethylene-based resin include polymers of tetrafluoroethylene, such as Teflon (registered trademark). Examples of the cycloolefin polymer-based resin include addition copolymers of norbornenes, hydrogenated ring-opening metathesis polymers of norbornenes, transannular polymers of alkylidene norbornenes, addition polymers of norbornenes, hydrogenated polymers of non-polymerizable 1,2- and 1,4-cyclopentadiene, ring-opening polymers of conjugated dienes, and the like. Examples of the unsaturated polyester-based resin include resins obtained by dissolving a polyester obtained by a condensation reaction of maleic anhydride and glycol in styrene or methyl methacrylate and heating and curing it.

[0127] Examples of the vinyltriazine-based resin include resins obtained by polymerizing 2-vinyl-4,6-diamino-1,3,5-triazine. Examples of the polyphenylene sulfide-based resin include resins having a linear structure in which benzene rings and sulfur atoms are alternately bonded. Examples of the crosslinkable polyphenylene oxide-based resin include a polymer alloy of polyphenylene ether obtained by polymerizing 2,6-dimethylphenylene oxide, which is a heat-resistant polyether resin, and polystyrene. Examples of the condensation resin include starch, phenol resin, urea resin, melamine resin, polycarbonate resin, etc., in addition to the above polyamide resin and polyester resin.

[0128] For example, if a polysiloxane resin is exemplified among the above resins, it is obtained by hydrolysis of a silane compound followed by dehydration condensation. This hydrolysis and condensation can be obtained under the hydrolysis conditions of the above silane coupling agent.

[0129] The silane compound can be produced by a combination of a tetrafunctional silane (a silane compound having four hydrolyzable groups), a trifunctional silane (a silane compound having three hydrolyzable groups and one organic group), a difunctional silane (a silane compound having two hydrolyzable groups and two organic groups), and a monofunctional silane (a silane compound having one hydrolyzable group and three organic groups). For example, a polysiloxane-based resin obtained by a combination of a tetrafunctional silane and a trifunctional silane can be mentioned.

[0130] Examples of the tetrafunctional silane include tetraethoxysilane and tetramethoxysilane. In particular, tetraethoxysilane can be preferably used.

[0131] Examples of the trifunctional silane include methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltriethoxy Alkyl silanes such as silane, octyltriethoxysilane, and decyltrimethoxysilane, Aryl silanes such as phenyltrimethoxysilane, phenyltriethoxysilane, phenylmethyltrimethoxysilane, and phenylmethyltriethoxysilane, Vinyl silanes such as vinyltrimethoxysilane and vinyltriethoxysilane, Epoxy silanes such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane, Styryl silanes such as p-styryltrimethoxysilane, methacrylic silanes such as 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane, Acrylic silanes such as 3-acryloxypropyltrimethoxysilane, Amine silanes such as N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N,N-dimethylaminopropyltrimethoxysilane, and the hydrochloride of N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, Isocyanurate silanes such as tris-(trimethoxysilylpropyl)isocyanurate and diallyl(trimethoxysilylpropyl)isocyanurate, Ureido silanes such as 3-ureidopropyltrialkoxysilane, Mercapto silanes such as 3-mercaptopropyltrimethoxysilane, Isocyanate silanes such as 3-isocyanatopropyltriethoxysilane can be mentioned.

[0132] Examples of the bifunctional silane include 3-glycidoxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane.

[0133] Examples of the polysiloxane resin include a polysiloxane resin obtained by copolymerizing tetraethoxysilane, methyltrimethoxysilane, and phenyltrimethoxysilane, and a polysiloxane resin obtained by copolymerizing diallyl(trimethoxysilylpropyl)isocyanurate, tetraethoxysilane, methyltrimethoxysilane, and N,N-dimethylaminopropyltrimethoxysilane. The weight average molecular weight of these linear to spherical polysiloxane resins can be set in the range of 1000 to 100,000, or 1000 to 5000.

[0134] For example, the above polysiloxane resin can be dissolved in a glycol-based solvent such as propylene glycol ethyl ether, and silica particles can be mixed at a compounding ratio of 100 phr. Then, a varnish solvent-substituted with propylene glycol monomethyl ether at 50 Torr and 80 °C can be produced as a coating composition. The concentration of silica in these coating compositions can be set to 1 to 30% by mass, or 5 to 30% by mass, or 3 to 10% by mass. And the particle diameter by the dynamic light scattering method in the coating composition can be set in the range of 10 to 200 nm, or 10 to 100 nm, or 30 to 90 nm. For example, when a transparent film is used as a substrate, the above coating composition is applied and heat-dried at 80 to 100 °C for 1 to 60 minutes to obtain a laminated substrate having a film thickness of 0.1 to 100 μm, or 0.1 to 30 μm, or 1 to 10 μm, or 1 to 3 μm.

[0135] The dielectric constant and dielectric tangent of these transparent film-like substrates can be measured. In the present invention, the above varnish composition and composite composition can be used for semiconductor device materials, semiconductor element materials, semiconductor resist materials, nanoimprinting, insulating film materials, copper-clad laminate materials, printed circuit board materials, printed board materials, printing ink materials, pigments, paints, sealant materials, hard coat materials, 3D printing materials, antireflection film materials, structural color forming members, in-vehicle part materials, electronic component materials, mechanical element parts, adhesive materials, battery materials, power generation materials, charge imparting materials, conductivity imparting materials, powder fluidity imparting materials, cosmetic materials, flexible wiring materials, liquid crystal display materials, organic EL display materials, micro LED display materials, QD-EL display materials, flexible display materials, antenna materials, optical wiring materials, or sensing materials.

[0136] Among the above applications, the case of using the above particles in a curable material having thermosetting or photocuring properties, particularly in a photosensitive material, will be described below. An organic resin is selected and mixed with a thermosetting or photocurable resin to obtain a film-forming composition. And it can be made into a cured product by including 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, photo radical generator), or an acid generator-based curing agent (thermal acid generator, or photo acid generator). The film-forming composition of the present invention containing an organic resin and a curing agent can be applied or filled on a substrate and 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, a photocurable polyfunctional acrylate can be preferably used.

[0137] Examples of the polyfunctional acrylate include polyfunctional acrylates having bifunctional, trifunctional, tetrafunctional or more functional groups in the molecule, such as neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate and the like. These polyfunctional acrylates can also be described below.

[0138] [Chemical formula]

[0139] [Chemical formula]

[0140] [Chemical formula]

[0141] [Chemical formula]

[0142] The film-forming composition of the present invention can contain a surfactant (leveling agent). As the surfactant (leveling agent), an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, and a silicone-based surfactant can be used. The surfactant (leveling agent) can be added in the range of 0.01 to 5 phr, or 0.01 to 1 phr with respect to the organic resin. Examples of the anionic surfactant used in the present invention include sodium salts and potassium salts of fatty acids, alkylbenzene sulfonates, higher alcohol sulfates, polyoxyethylene alkyl ether sulfates, α-sulfo fatty acid esters, α-olefin sulfonates, monoalkyl phosphate esters, and alkane sulfonates. For example, alkylbenzene sulfonates include sodium salts, potassium salts, and lithium salts, such as sodium C10 - C16 alkylbenzene sulfonate, C10 - C16 alkylbenzene sulfonic acid, sodium alkylnaphthalene sulfonate, and the like.

[0143] Higher alcohol sulfate salts include sodium dodecyl sulfate (sodium lauryl sulfate) with 12 carbon atoms, triethanolamine lauryl sulfate, triethanolammonium lauryl sulfate, and the like.

[0144] Polyoxyethylene alkyl ether sulfates include sodium polyoxyethylene styrenated phenyl ether sulfate, ammonium polyoxyethylene styrenated phenyl ether sulfate, sodium polyoxyethylene decyl ether sulfate, ammonium polyoxyethylene decyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, ammonium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene tridecyl ether sulfate, sodium polyoxyethylene oleyl cetyl ether sulfate, and the like. α - Olefin sulfonates include sodium α - olefin sulfonate and the like.

[0145] Alkane sulfonates include sodium 2 - ethylhexyl sulfate and the like.

[0146] The cationic surfactants used in the present invention include, for example, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, and amine salt - based agents.

[0147] Alkyltrimethylammonium salts are quaternary ammonium salts and have chloride ions or bromide ions as counterions. For example, dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, coconut alkyltrimethylammonium chloride, alkyl (C16 - 18) trimethylammonium chloride, and the like can be mentioned. Dialkyldimethylammonium salts have two lipophilic main chains and two methyl groups. Examples include bis(hydrogenated tallow)dimethylammonium chloride. For example, didecyldimethylammonium chloride, diacylalkyldimethylammonium chloride, dihydrogenated tallow alkyldimethyammonium chloride, dialkyl(C14-18)dimethylammonium chloride, etc. can be mentioned.

[0148] Alkyldimethylbenzylammonium salts are quaternary ammonium salts with one lipophilic main chain, two methyl groups, and a benzyl group, and benzalkonium chloride can be mentioned. For example, alkyl(C8-18)dimethylbenzylammonium chloride can be mentioned. As amine salt-based agents, those in which one or more hydrogen atoms of ammonia are substituted with hydrocarbon groups, for example, N-methylbis(hydroxyethyl)amine fatty acid ester hydrochloride can be mentioned.

[0149] The amphoteric surfactants used in the present invention include N-alkyl-β-alanine type alkylaminofatty acid salts, alkyl carboxybetaine type alkylbetaines, and N,N-dimethyldodecylamine oxide type alkylamine oxides. Examples thereof include lauryl betaine, stearyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, and lauryldimethylamine oxide.

[0150] The nonionic surfactants used in the present invention are selected from polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, alkyl glucosides, polyoxyethylene fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and fatty acid alkanolamides. For example, as the polyoxyethylene alkyl ether, 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, polyoxyethylene isodecyl ether, etc. can be mentioned.

[0151] As the polyoxyethylene alkylphenol ether, there are polyoxyethylene styrenated phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene tribenzylphenyl ether, etc.

[0152] As the alkyl glucoside, there are decyl glucoside, lauryl glucoside, etc.

[0153] As the polyoxyethylene fatty acid ester, there are polyoxyethylene monolaurate, p olyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol dioleate, polypropylene glycol dioleate, etc. Examples of sorbitan fatty acid esters include sorbitan monocaprylate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan mono sesquioleate, and ethylene oxide adducts thereof.

[0154] 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, polyoxyethylene sorbitan triisostearate, and the like.

[0155] Examples of fatty acid alkanolamides include coconut oil fatty acid diethanolamide, tallow fatty acid diethanolamide, lauric acid diethanolamide, oleic acid diethanolamide, and the like. Furthermore, 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, sucrose fatty acid ester, and the like can be mentioned.

[0156] A silicone-based surfactant can be used. The silicone-based surfactant is a compound having a repeating unit containing a siloxane bond in the main chain. The weight average molecular weight of the silicone-based surfactant can be used in the range of 500 to 50,000. These may be modified silicone-based surfactants, and examples include structures in which an organic group is introduced into the side chain and / or the terminal of the polysiloxane. Examples of the organic group include an amino group, an epoxy group, an alicyclic epoxy group, a carbinol group, a mercapto group, a carboxyl group, an aliphatic ester group, an aliphatic amide group, and a polyether group. Examples of the silicone-based surfactant 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, Toray Silicone SH8400 (manufactured by Toray Dow Corning Co., Ltd.), Silwet l-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, L-8610 (manufactured by Momentive Performance Materials), KP-341, KF-6001, KF-6002 (manufactured by Shin-Etsu Silicone Co., Ltd.), BYK307, BYK323, BYK330 (manufactured by BYK-Chemie), etc. For example, a product named L-7001 (manufactured by DOWSIL) can be preferably used as the polyether-modified silicone.

[0157] In the present invention, a film-forming composition containing the above organic solvent sol and an organic resin is obtained. The film-forming composition can be obtained by removing the organic solvent in the organic solvent sol to obtain a film-forming composition containing silica particles and an organic resin. In the case of the thermosetting film-forming composition in the above film-forming composition, a thermosetting agent can be added in the range of 0.01 to 50 phr, or 0.01 to 10 phr, to a resin containing a functional group such as an epoxy group or a (meth)acryloyl group. For example, the thermosetting agent is 0.5 to 1.5 equivalents, preferably 0.8 to It can be contained in a proportion of 1.2 equivalents. The equivalent of the thermosetting agent to the curable resin is indicated by the equivalent ratio of the thermosetting agent to the functional group.

[0158] Examples of the thermosetting agent include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polymercaptans, acid anhydrides, thermal radical generators, thermal acid generators, etc. Particularly, radical generator-based curing agents, acid anhydride-based curing agents, and amine-based curing agents are preferred. These thermosetting agents can be used by dissolving them in a solvent even if they are solid. However, since the evaporation of the solvent causes a decrease in the density of the cured product, a decrease in strength due to the formation of pores, and a decrease in water resistance, it is preferable that the curing agent itself is liquid at normal temperature and pressure. Examples of the phenolic resin include phenol novolak resin, cresol novolak resin, etc.

[0159] Examples of the amine-based curing agent 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, m-xylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, 3,3'-diethyl-4,4'-diaminodiphenylmethane, diethyltoluenediamine, etc. Among these, liquid diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, m-xylenediamine, isophoronediamine, diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, diethyltoluenediamine, etc. can be preferably used.

[0160] The polyamide resin is produced by the condensation of dimer acid and polyamine, and is a polyamide amine having a primary amine and a secondary amine in the molecule.

[0161] Examples of the imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, epoxy imidazole adduct, and the like.

[0162] The polymercaptan is, for example, one having a mercaptan group at the end of a polypropylene glycol chain or one having a mercaptan group at the end of a polyethylene glycol chain, and a liquid one is preferred. As the acid anhydride-based curing agent, an anhydride of a compound having a plurality of carboxyl groups in one molecule is preferred. Examples of these acid anhydride-based curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic 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, methylcyclohexenedicarboxylic anhydride, chlorendic anhydride, and the like. Examples of the thermal acid generator include sulfonium salts and phosphonium salts, and sulfonium salts are preferably used. For example, the following compounds can be exemplified.

[0163]

Chemical formula

[0164] R includes an alkyl group having 1 to 12 carbon atoms and an aryl group having 6 to 20 carbon atoms, and an alkyl group having 1 to 12 carbon atoms is particularly preferred.

[0165] Among these, methyltetrahydrophthalic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride (methyl nadic anhydride, methyl hymic anhydride), hydrogenated methyl nadic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, methylhexahydrophthalic anhydride, and a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, which are liquid at normal temperature and pressure, are preferred. These liquid acid anhydrides have a viscosity of about 10 mPa·s to 1000 mPa·s as measured at 25°C. Examples of the thermal radical generator include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), dimethyl 2,2'-azobis(2-methylpropionate), 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, benzoyl peroxide, etc. These can be obtained from Tokyo Chemical Industry Co., Ltd.

[0166] In addition, when obtaining the above-mentioned cured product, a curing aid may be appropriately used in combination. Examples of the curing aid include organic phosphorus compounds such as triphenylphosphine and tributylphosphine, quaternary phosphonium salts such as ethyltriphenylphosphonium bromide and diethyl methyltriphenylphosphonium phosphate, 1,8-diazabicyclo(5,4,0)undec-7-ene, salts of 1,8-diazabicyclo(5,4,0)undec-7-ene and octylic acid, zinc octylate, quaternary ammonium salts such as tetrabutylammonium bromide. These curing aids can be contained in a proportion of 0.001 to 0.1 part by mass with respect to 1 part by mass of the curing agent.

[0167] A thermosetting varnish can be obtained by mixing a resin, a curing agent, and, if desired, a curing aid in the composition. These mixtures can be carried out using a stirring blade or a kneader in a reaction vessel. 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. The obtained thermosetting film-forming composition is a thermosetting coating composition, and has a suitable viscosity for use as, for example, a liquid sealant. The liquid thermosetting film-forming composition can be prepared to any viscosity, and can be partially sealed at any location for use as a transparent sealant for LEDs, etc., by casting, potting, dispenser, printing, etc. The liquid thermosetting composition is directly mounted on an LED, etc., in the liquid state, by the above-mentioned method, and then dried and cured to obtain a cured product.

[0168] The 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. In the case of the photocurable resin composition, the above-mentioned film-forming composition is an epoxy group or a (meth)aryl group. A photocuring agent (photoradical generator, photoacid generator) can be added in the range of 0.01 to 50 phr or 0.01 to 10 phr to a resin containing a functional group such as an acryloyl group, and 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 to a functional group such as an epoxy group or a (meth)acryloyl group. The equivalent of the photocuring agent to the curable resin is represented by the equivalent ratio of the photocuring agent to the functional group. The photoradical generator is not particularly limited as long as it generates radicals directly or indirectly upon irradiation with light.

[0169] Examples of the photo radical generator include photo radical polymerization initiators. Examples of the photo radical polymerization initiator include imidazole compounds, diazo compounds, bisimidazole compounds, N-aryl glycine compounds, organic azide compounds, titanocene compounds, aluminate compounds, organic peroxides, N-alkoxypyridinium salt compounds, and thioxanthone compounds. Examples of the azide compound include p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, 4,4'-diazidochalcone, 4,4'-diazidodiphenyl sulfide, and 2,6-bis(4'-azidobenzal)-4-methylcyclohexanone. Examples of the diazo compound include 1-diazo-2,5-diethoxy-4-p-tolyl mercaptobenzene borofluoride, 1-diazo-4-N,N-dimethylaminobenzene chloride, and 1-diazo-4-N,N-diethylaminobenzene borofluoride. Examples of the bisimidazole compound include 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)1,2'-bisimidazole, and 2,2'-bis(o-chlorophenyl)4,5,4',5'-tetraphenyl-1,2'-bisimidazole.Examples of the titanocene compound 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-titanium-bis(2,4-difluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,3,4,5,6-pentafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,3,5,6-tetrafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,6-difluorophenyl), and dicyclopentadienyl-titanium-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl).

[0170] Examples of the photo radical generator also include 1,3-di(tert-butyldioxycarbonyl)benzophenone, 3,3’,4,4’-tetrakis(tert-butyldioxycarbonyl)benzophenone, 3-phenyl-5-isoxazolone, 2-mercaptobenzimidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone.

[0171] These photo radical polymerization agents can be obtained, for example, under the trade name Irgacure TPO (the component is 2,4,6-trimethylbenzoyldiphenylphosphine oxide) (c1-1-1) manufactured by BASF, under the trade name Omnirad819 (the component is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) (c1-1-2) manufactured by IGM RESINS, and under the trade name Irgacure 184 (the component is 1-hydroxycyclohexylphenylketone) (c1-1-3) manufactured by IGM RESINS.

[0172] [Chemical formula]

[0173] The photoacid generator is not particularly limited as long as it can generate an acid directly or indirectly upon light irradiation. 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, selenium salts, metallocene complexes, iron arene complexes, etc., which can be used. Examples of the onium salt used as the above photoacid generator include, as iodonium salts, 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 tetrafluoroborate, bis(p-tert-butylphenyl)iodonium chloride, bis(p-chlorophenyl)iodonium chloride, bis(p-chlorophenyl)iodonium tetrafluoroborate, and further bis(alkylphenyl)iodonium salts such as bis(4-t-butylphenyl)iodonium hexafluorophosphate, alkoxycarbonylalkoxy-trialkylaryliodonium salts (for example, 4-[(1-ethoxycarbonyl-ethoxy)phenyl]-(2,4,6-trimethylphenyl)-iodonium hexafluorophosphate, etc.), bis(alkoxyaryl)iodo Examples of the iodonium salt include bis(alkoxyphenyl)iodonium salts such as (4-methoxyphenyl)phenyl iodonium hexafluoroantimonate. Examples of the sulfonium salt include triphenylsulfonium chloride, triphenylsulfonium bromide, tri(p-methoxyphenyl)sulfonium tetrafluoroborate, tri(p-methoxyphenyl)sulfonium hexafluorophosphate, tri(p-ethoxyphenyl)sulfonium tetrafluoroborate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate and other triphenylsulfonium salts, (4-phenylthiophenyl)diphenylsulfonium hexafluoroantimonate, (4 - phenylthiophenyl)diphenylsulfonium hexafluorophosphate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluoroantimonate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluorophosphate, (4-methoxyphenyl)diphenylsulfonium hexafluoroantimonate and other sulfonium salts.

[0174] Examples of the phosphonium salt include triphenylphosphonium chloride, triphenylphosphonium bromide, tri(p-methoxyphenyl)phosphonium tetrafluoroborate, tri(p-methoxyphenyl)phosphonium hexafluorophosphate, tri(p-ethoxyphenyl)phosphonium tetrafluoroborate, 4-chlorobenzenediazonium hexafluorophosphate, benzyltriphenylphosphonium hexafluoroantimonate and other phosphonium salts. Furthermore, examples include selenium salts such as triphenylselenium hexafluorophosphate, and metallocene complexes such as (η5 or η6-isopropylbenzene)(η5-cyclopentadienyl)iron(II) hexafluorophosphate.

[0175] In addition, the following compounds can also be used as photoacid generators.

[0176]

Chem.

[0177]

Chem.

[0178]

Chem.

[0179]

Chem.

[0180]

Chem.

[0181]

Chem.

[0182]

Chem.

[0183]

Chem.

[0184]

Chem.

[0185] As the photoacid generator, sulfonium salt compounds and iodonium salt compounds are preferred. As their anion species, CF3SO3 - , C4F9SO3 - , C8F 17 SO3- , camphorsulfonic acid anion, tosylate anion, BF4 - , PF6 - , AsF6 - and SbF6 - and the like. Anionic species such as phosphorus hexafluoride and antimony hexafluoride showing particularly strong acidity are preferred. The film-forming composition of the present invention may contain conventional additives as necessary. Examples of such additives include pigments, colorants, thickeners, sensitizers, defoamers, coating property improvers, lubricants, stabilizers (such as antioxidants, heat stabilizers, and light stabilizers), plasticizers, dissolution accelerators, fillers, antistatic agents, and the like. These additives may be used alone or in combination of two or more.

[0186] Examples of the coating method of the film-forming composition of the present invention include flow coating method, spin coating method, spray coating method, screen printing method, casting method, bar coating method, curtain coating method, roll coating method, gravure coating method, dipping method, slit method, and the like. In the present invention, the photocurable coating composition (film-forming composition) can be applied onto a substrate and cured by light irradiation. Heating can also be performed before and after light irradiation. The thickness of the coating film can be selected from the range of about 0.01 μm to 10 mm according to the use of the cured product. For example, when used for a photoresist, it can be about 0.05 to 10 μm (particularly 0.1 to 5 μm), when used for a printed wiring board, it can be about 5 μm to 5 mm (particularly 100 μm to 1 mm), and when used for an optical thin film, it can be about 0.1 to 100 μm (particularly 0.3 to 50 μm). When obtaining a transparent film, the visible light transmittance of the film can be 80% or more, or 90% or more, typically 90 to 96%.

[0187] The light for irradiation or exposure when using a photoacid generator may be, for example, gamma rays, X-rays, ultraviolet rays, visible light, etc., and usually, it is often visible light or ultraviolet rays, particularly ultraviolet rays. The wavelength of the light is, for example, about 150 to 800 nm, preferably 150 to 600 nm, and more preferably about 150 to 400 nm. The irradiation light amount varies depending on the thickness of the coating film, but can be, for example, 2 to 20000 mJ / cm 2 , preferably 5 to 5000 mJ / cm 2 or so. The light source can be selected according to the type of light rays to be exposed. For example, in the case of ultraviolet rays, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a deuterium lamp, a halogen lamp, laser light (helium-cadmium laser, excimer laser, etc.) can be used. By such light irradiation, the curing reaction of the composition proceeds. When using a thermal acid generator or when heating the coating film as necessary after light irradiation using a photoacid generator, it is carried out, for example, at about 60 to 350 °C, preferably about 100 to 300 °C. The heating time can be selected from the range of 3 seconds or more (for example, about 3 seconds to 5 hours), and can be carried out, for example, for 5 seconds to 2 hours, preferably about 20 seconds to 30 minutes, and usually can be carried out for about 1 minute to 3 hours (for example, 5 minutes to 2.5 hours).

[0188] Furthermore, when forming a pattern or an image (for example, when manufacturing a printed wiring board, etc.), the coating film formed on the substrate may be pattern-exposed. This pattern exposure may be carried out by scanning laser light, or may be carried out by irradiating light through a photomask. By developing (or dissolving) the non-irradiated region (unexposed portion) generated by such pattern exposure with a developer, a pattern or an image can be formed. An alkaline aqueous solution or an organic solvent can be used as the developer. Examples of the aqueous alkali solution include aqueous solutions of alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, potassium carbonate, and sodium carbonate; aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and amine aqueous solutions such as ethanolamine, propylamine, and ethylenediamine.

[0189] The alkali developer is generally an aqueous solution of 10% by mass or less, preferably an aqueous solution of 0.1 to 3.0% by mass. Further, alcohols or surfactants can be added to the above developer and used. These are preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the developer. Among these, an aqueous solution of 0.1 to 2.38% by mass of tetramethylammonium hydroxide or ethyltrimethylammonium hydroxide can be used. As the organic solvent for the developer, general organic solvents can be used. For example, 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. can be mentioned, and these can be used as a mixture of one or more of them. In particular, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl lactate, etc. can be preferably used.

[0190] In the present invention, an adhesion promoter can be added for the purpose of improving the adhesion to the substrate after development. These adhesion promoters include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, chloromethyldimethylchlorosilane, etc., alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, etc., silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, trimethylsilylimidazole, etc., silanes such as vinyltrichlorosilane, 3-chloropropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-(N-piperidinyl)propyltrimethoxysilane, etc., heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, mercaptopyrimidine, etc., ureas such as 1,1-dimethylurea, 1,3-dimethylurea, or thiourea compounds. One or more of the above adhesion promoters can be used in combination. The addition amount of these adhesion promoters is usually 18% by mass or less, preferably 0.0008 to 9% by mass, more preferably 0.04 to 9% by mass in the solid content.

[0191] The present invention may contain a sensitizer. Examples of the sensitizer that can be used include anthracene, phenothiazine, perylene, thioxanthone, benzophenone thioxanthone, etc. Further, examples of the sensitizing dye include thiopyrylium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, pyrylium salt dyes, etc. Particularly preferred is an anthracene-based sensitizer. When used in combination with a cationic curing catalyst (photo-sensitive cationic polymerization initiator), the sensitivity is dramatically improved, and it also has a radical polymerization initiation function. In the hybrid type that combines the cationic curing system and the radical curing system of the present invention, the catalyst species can be simplified. As specific anthracene compounds, dibutoxyanthracene, dipropoxyanthraquinone, etc. are effective. The addition amount of the sensitizer is used in a proportion of 0.01 to 20% by mass, preferably 0.01 to 10% by mass in the solid content. The composition of the present invention can be photocured or thermally cured using a photo radical generator, a thermal radical generator, a photoacid generator or a thermal acid generator. When using a photoacid generator or a thermal acid generator, for example, a commonly used epoxy curing agent (such as an amine or an acid anhydride) is not used or, even if used, their content is extremely low, so the storage stability of this composition is improved.

[0192] The above composition has been found to be applicable to cationic photopolymerization. It has a higher curing rate than conventional liquid epoxy compounds (such as alicyclic epoxy compounds having an epoxycyclohexyl ring). Since the curing rate is fast, it is possible to reduce the addition amount of the acid generator or use a weak acid-based acid generator. The reduction of the acid generator is important for preventing metal corrosion because acid active species may remain after UV irradiation. Since the curing rate is fast, thick film curing is possible. Curing by UV irradiation can be applied to materials (equipment) that are sensitive to heat.

[0193] The thermosetting material and photocuring material using the film-forming composition of the present invention have characteristics such as rapid hardening property, transparency, and small curing shrinkage, and can be used for coating and adhesion of electronic components, optical components (antireflection films), and precision mechanical components. In the present invention, silica particles that can be redispersed in a developer containing an organic solvent or an alkaline aqueous solution can be included in the coating composition. Based on the surface potential present on the surface of the hollow silica particles, it can be made soluble in the developer, but it is possible to show selective developability only with an organic solvent by bonding an organic functional group to the surface, or to show selective developability only with an alkaline aqueous solution. These organic functional groups are achieved by coating the silica particles with the above-mentioned silane coupling agent, adding an amine to the silica sol, or adding a surfactant.

Examples

[0194] Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. The solvents, resins, metal oxide particles, silanes, and pH adjusters used in the examples and comparative examples are as follows. (Solvent · Resin) MeOH: Methanol IPA: Isopropyl alcohol AC: Acetone MEK: Methyl ethyl ketone PGME: Propylene glycol monomethyl ether PGEE: Propylene glycol monoethyl ether PGMEA: Propylene glycol monomethyl ether acetate DMAC: N, N - Dimethylacetamide NMP: N - Methyl - 2 - pyrrolidone EL: Ethyl lactate HBM: Methyl - 2 - hydroxyisobutyrate GBL: γ - Butyrolactone MIBK: Methyl isobutyl ketone AcMO: 4 - Acryloylmorpholine THFAc: Tetrahydrofurfuryl acrylate

[0195] (Metal oxide particles with a refractive index of 1.4 to 3.0) · Product name MT-ST: Methanol-dispersed silica sol with an average primary particle size of 12 nm (manufactured by Nissan Chemical Industries, Ltd., methanol-dispersed sol of solid silica particles, refractive index 1.45) · Product name PGM-ST: PGME-dispersed silica sol with an average primary particle size of 12 nm (manufactured by Nissan Chemical Industries, Ltd., PGME-dispersed sol of solid silica particles, refractive index 1.45) · Product name Snowtex MSH: Water-dispersed silica sol with an average primary particle size of 17 nm (manufactured by Nissan Chemical Industries, Ltd., water-dispersed sol of solid silica particles, refractive index 1.45) · Product name Snowtex O-40: Water-dispersed silica sol with an average primary particle size of 22 nm (manufactured by Nissan Chemical Industries, Ltd., water-dispersed sol of solid silica particles, refractive index 1.45) · Product name MA-ST-L: Methanol-dispersed silica sol with an average primary particle size of 45 nm (manufactured by Nissan Chemical Industries, Ltd., methanol-dispersed sol of solid silica particles, refractive index 1.45) · Product name ST-ZL: Water-dispersed silica sol with an average primary particle size of 80 nm (manufactured by Nissan Chemical Industries, Ltd., water-dispersed sol of solid silica particles, refractive index 1.45) · Product name PGM-ST-ZL: PGME-dispersed silica sol with an average primary particle size of 80 nm (manufactured by Nissan Chemical Industries, Ltd., PGME-dispersed sol of solid silica particles, refractive index 1.45) · Product name PL-3: Water-dispersed silica sol with an average primary particle size of 35 nm (manufactured by Fuso Chemical Industry Co., Ltd., water-dispersed sol of solid silica particles, refractive index 1.43)

[0196] (Metal oxide particles with a refractive index of 1.1 to less than 1.4) · Product name HKT-A20-40D: Water-dispersed silica sol with an average primary particle size of 40 nm (manufactured by Ningbo Dilato, water-dispersed sol of hollow silica particles, refractive index 1.26) · Product name HKT-A20-70D: Water-dispersed silica sol with an average primary particle size of 71 nm (manufactured by Ningbo Dilato, water-dispersed sol of hollow silica particles, refractive index 1.19)

[0197] (Silanes) ·MPDMS: Methylphenyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) ·MPMDMS: 3-Methacryloxypropylmethyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) ·TMSO: Hexamethyldisiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) ·TMS: Trimethylmethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) ·DTMS: Decyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) ·PTMS: Phenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) ·MTMS: Methyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) ·TEOS: Tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) ·DEDPS: Diethoxydiphenylsilane (manufactured by Tokyo Chemical Industry Co., Ltd.) ·APMDMS: 3-Acryloxypropylmethyldimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0198] (Basic compound) DiPA: Diisopropylamine DiPEA: Diisopropylethylamine 1 mass% aqueous solution of sodium hydroxide

[0199] (Additive) ·MEHQ: 4-Methoxyphenol According to the following method, the physical properties of the above-mentioned aqueous silica sol, the dispersion liquids of the surface-modified silica particles prepared in the examples and comparative examples, and the silica sol and dispersion liquids during the dispersion liquid manufacturing process were measured and evaluated.

[0200] (Measurement of metal oxide particle concentration) The metal oxide particle concentration of the metal oxide sol (also referred to as silica concentration in the case of silica sol) was calculated by taking the sol in a crucible, removing the solvent by heating, firing at 1000 °C, and weighing the firing residue.

[0201] (pH measurement method for aqueous metal oxide sol) The pH of the aqueous dispersion metal oxide sol was measured using a pH meter (manufactured by Toa DKK Corporation, product name: MM-43X).

[0202] (Method for Measuring the pH of an Organic Solvent-Dispersed Metal Oxide Sol) The pH of the organic solvent-dispersed metal oxide sol was measured with a pH meter (manufactured by Toa DKK Corporation, product name: MM-43X) on a liquid obtained by mixing a target sample containing the organic solvent-dispersed metal oxide sol, MeOH, and pure water at a mass ratio of 1:1:1.

[0203] (Water Content) The water content in the metal oxide sol was measured by the Karl Fischer titration method using a Karl Fischer moisture meter (manufactured by Kyoto Electronics Industry Co., Ltd., product name: MKA-610).

[0204] (Organic Solvent Content) The organic solvent content in the metal oxide sol was measured using gas chromatography (manufactured by Shimadzu Corporation, product name: GC-2014s) under the conditions described below. Column: 3 mm × 1 m glass column Packing material: Product name Porapak Q Column temperature: 130 to 230 °C (temperature increase 8 °C / min) Carrier: N2 40 mL / min Detector: FID Injection volume: 1 μL Internal standard: Acetonitrile was adopted.

[0205] (Measurement of Viscosity) The viscosity of the metal oxide sol was measured using an Ostwald viscometer (manufactured by Shibata Science Co., Ltd.). The measurement temperature was 20 °C.

[0206] (Measurement of the Viscosity of the Redispersed Sol (EMS Viscosity)) The viscosity of the redispersed solvent (redispersed sol) obtained by mixing the dried powder obtained by drying metal oxide particles or a metal oxide sol and a solvent was measured using an EMS viscometer (manufactured by Kyoto Electronics Co., Ltd., product name EMS-1000S). The measurement temperature was 20 °C.​

[0207] (Measurement of the specific surface area (S N2 ) by the nitrogen adsorption method) The specific surface area (S N2 ) of the metal oxide particles by the nitrogen adsorption method was measured by removing the water-soluble cations in the aqueous dispersion of the metal oxide sol with a cation exchange resin (manufactured by Dow Chemical Co., trade name: Amberlite IR-120B), drying the metal oxide sol at 290 °C to obtain a measurement sample, and using a specific surface area measuring device Monosorb (manufactured by Contactrohm Instruments Japan Co., Ltd.) for the nitrogen adsorption method.

[0208] (Average primary particle diameter) The average primary particle diameter of the metal oxide particles was calculated from the specific surface area S N2 (m 2 / g) obtained by the above nitrogen adsorption method. When the metal oxide particles are silica particles, the average primary particle diameter was calculated by converting to spherical particles using the following formula from the specific surface area S N2 (m 2 / g) obtained by the above nitrogen adsorption method. The average primary particle diameter was determined by the following formula.

[0209] For example, when the silica with a density of the metal oxide of 2.2 g / cm 3 is used, the average primary particle diameter was calculated using the following formula. Average primary particle diameter (nm) = 2720 / S N2 (m 2 / g)

[0210] (Average particle diameter by the DLS method (dynamic light scattering average particle diameter)) The average particle diameter by the DLS method was measured using a dynamic light scattering particle size measuring device (manufactured by Malvern Panalytical, product name: Zetasizer Nano). The refractive index of the particles, the refractive index of the solvent, the viscosity of the solvent, etc. were set according to the measurement sample, and the measurement temperature was carried out in accordance with the refractive index of the solvent and the viscosity of the solvent used. 0.1 g of the target metal oxide sol was taken in a glass cell with an optical path length of 10 mm, and the same solvent as the main component of the dispersion medium of the metal oxide sol was further added to obtain a metal oxide sol in which the metal oxide particle concentration was adjusted so that the count rate was 200 to 400 kcps when the attenuator showed 7. For example, in the case of a MEK-dispersed metal oxide sol, MEK was added to obtain a metal oxide sol in which the metal oxide particle concentration was adjusted so that the count rate was 200 to 400 kcps when the attenuator showed 7. The prepared metal oxide sol was placed in the above cell and adjusted so that the height from the bottom of the cell to the liquid surface was about 1 cm, and the average particle diameter by dynamic light scattering of the metal oxide sol when the attenuator showed 7 was measured. The Z-average particle diameter was adopted as the average particle diameter by dynamic light scattering.

[0211] (Measurement of refractive index of metal oxide particles) The measurement was carried out according to the following procedures 1) to 3). 1) Preparation of an aqueous sol-formulated varnish of metal oxide particles 20.00 g of 3-glycidoxypropyltrimethoxysilane (GPS, manufactured by Momentive, product name SILQUEST A-187T) was weighed into a plastic container, and 18.57 g of methanol and 4.57 g of 0.01 N hydrochloric acid aqueous solution were added thereto, and the mixture was stirred at room temperature for 5 hours. 6.00 g of a methanol solution of aluminum 2,4-pentanedionate (Al(acac)3) (10 mass% Al(acac)3) prepared in advance was added as a curing agent and stirred for 10 minutes to prepare a partial hydrolyzate of GPS (concentration: 43 mass%). GPS partial hydrolyzate, water, methanol, and 0.25 g of a methanol solution (10 mass% L-7604) of a leveling agent (DOWSIL trademark L-7604) were weighed into a brown bottle in amounts such that the total amount was 25.00 g and the final solvent composition was water / methanol = 9 / 1 by weight ratio, and the amounts of metal oxide in the metal oxide particle aqueous sol were 50 phr, 100 phr, and 150 phr. After stirring at room temperature for 30 minutes, a metal oxide particle aqueous sol-containing varnish (solid content concentration: 4 mass%, amount of metal oxide: 50 phr, 100 phr, 150 phr) was prepared.

[0212] 2) Preparation of metal oxide particle-containing film Approximately 1 mL of the metal oxide particle aqueous sol-containing varnish (amount of metal oxide: 50 phr, 100 phr, 150 phr) obtained in 1) was dropped onto a Si substrate treated with UV-O3, and using a spin coater (Mikasa Co., Ltd., Opticoat MS-B100), it was uniformly spread on the Si substrate under the conditions of rising to 200 rpm in 2 seconds, 200 rpm × 10 seconds, rising to 800 rpm in 2 seconds, 800 rpm × 5 seconds, and descending to 0 rpm in 5 seconds. Then, it was baked on a hot plate at 80 °C for 5 minutes and heat-treated in an oven at 120 °C for 1 hour to prepare a metal oxide particle-containing film (amount of metal oxide: 50 phr, 100 phr, 150 phr).

[0213] 3) Refractive index measurement of metal oxide particle-containing film and calculation of refractive index of metal oxide particles The refractive index of the metal oxide particle-containing film (amount of metal oxide: 50 phr, 100 phr, 150 phr) obtained in 2) was measured with an ellipsometer (Multi-Angle Spectroscopic Ellipsometer VASE manufactured by J.A. Woolam Japan Co., Ltd.). Separately, the refractive index of a film containing no metal oxide particles prepared in the same manner with only the partial hydrolyzate of GPS was also measured. The measured refractive indices of the coated films were plotted against the amount of metal oxide particles, and the refractive index of the metal oxide particles was determined by extrapolating so that the amount of metal oxide particles was 100 mass%.

[0214] (Measurement of degree of hydrophobicity) 5 mL of the metal oxide sol was evaporated to dryness under reduced pressure of 50 Torr and a bath temperature of 80 to 130 °C (120 °C for the DMAC-dispersed silica sol) using a rotary evaporator to obtain metal oxide powder. The obtained powder was pulverized in a mortar and dried again using a rotary evaporator under a reduced pressure of 50 Torr and a bath temperature of 130 °C to obtain a sample for measuring the degree of hydrophobicity. 50 mL of pure water was placed in a 100 mL beaker, 0.2 g of the above metal oxide powder was added, and the mixture was stirred using a magnetic stirrer. Thereafter, methanol was added dropwise, and the degree of hydrophobicity was calculated from the following formula based on the added amount X mL of methanol required until the metal oxide powder floating on the liquid surface completely sank into the liquid. Degree of hydrophobicity (volume %) = {(X) / (50 + X)} × 100

[0215] (Surface structure analysis of metal oxide particles) The surface structure of the metal oxide particles was analyzed using a 500 MHz nuclear magnetic resonance apparatus (model name "AVANCE III 500", manufactured by Bruker), equipped with a CP-MAS probe with a sample tube diameter of 4.0 mm, and measured under the following conditions. Measurement: CP-MAS Rotation speed: 8 kHz Number of integrations: 8000 times Relaxation waiting time: 2 sec. Contact time: 5000 μsec. Reference: DSS (1.534 ppm) LB: 60 Hz After the above measurement, the signals of a plurality of silanes having different substituents and bonding groups were peak-separated into the following M structure (monofunctional / in this example, the signal derived from monoalkoxysilane), D structure (bifunctional / in this example, the signal derived from dialkoxysilane), and T structure (trifunctional / in this example, the signal derived from trialkoxysilane) by curve fitting, and the peak areas were calculated respectively.

[0216] (Measurement of composition concentration) The concentration (mass %) of the composition was measured by weighing about 1.00 g of the composition into an aluminum cup, firing it at 200 °C for 2 hours, and weighing the firing residue.

[0217] (Measurement of average primary particle size by TEM (transmission electron microscope)) Particles in the metal oxide were photographed with a transmission electron microscope (trade name JEM-F200, manufactured by JEOL Ltd.). Approximately 300 arbitrarily selected particles were binarized using an automatic image processing analyzer (trade name LUZEX AP, manufactured by Nireco Corp.), and the diameter obtained by converting the projected area into a circle was measured as the average primary particle size (Heywood diameter).

[0218] (Measurement of D10, D50, and D90) D10, D50, and D90 were measured as follows: Particles in the metal oxide were photographed with a transmission electron microscope (trade name JEM-F200, manufactured by JEOL Ltd.). Approximately 300 arbitrarily selected particles were binarized using an automatic image processing analyzer (trade name LUZEX AP, manufactured by Nireco Corp.), and the D10, D50, and D90 of the metal oxide sol were measured as the particle size distribution from the diameters obtained by converting the projected area into a circle. D10, D50, and D90 were measured by the volume distribution method as the particle diameters corresponding to cumulative 10%, 50%, and 90% from the fine particle side showing the cumulative particle size distribution.

[0219] (Measurement of particle volume by TEM (transmission electron microscope)) The particles in the metal oxide were photographed with a transmission electron microscope (manufactured by JEOL Ltd., trade name JEM-F200), and approximately 2,000 arbitrarily selected particles were binarized using an automatic image processing and analysis device (manufactured by Nireco Corporation, trade name LUZEX AP). The diameter obtained by converting the projected area into a circle was measured as the average primary particle diameter (Heywood diameter), and the particle volume was calculated from the numerical value. The ratio of (volume of metal oxide particle A) / (volume of metal oxide particle B) was determined by measuring the particle size distribution of approximately 2,000 arbitrarily selected particles. The largest peak in the range of D50 to D90 was defined as metal oxide particle A, and the largest peak in the range of D10 to D50 was defined as metal oxide particle B. The average primary particle diameter and the number of each were measured. (Volume of metal oxide particle A) was calculated as (volume of one particle calculated from the average primary particle diameter of metal oxide particle A) × (number of metal oxide particles A), and (volume of metal oxide particle B) was calculated as (volume of one particle calculated from the average primary particle diameter of metal oxide particle B) × (number of metal oxide particles B).

[0220] (Measurement / Dissolution Method of Aluminum Content (B) Present in the Entire Silica Particles) The precisely weighed silica sol was dried, and 2.5 ml of nitric acid (manufactured by Kanto Chemical Co., Inc., product name: Nitric Acid 1.38, purity 60.0%) and 2.5 ml of 38% hydrofluoric acid (manufactured by Tama Chemical Industry Co., Ltd., product name: Hydrofluoric Acid) were added to 250 mg of the obtained particles and dissolved to obtain an aqueous solution. The amount of aluminum in the obtained aqueous solution was measured with an ICP emission spectrometer (manufactured by Rigaku Corporation, product name: CIROS120 EOP), and the amount of aluminum present in the entire silica particles was converted to Al2O3, and the ratio (Al2O3 (ppm) / SiO2) was determined with respect to the mass of SiO2 of the silica.

[0221] (Measurement / Leaching Method of Aluminum Content (A) Bonded to the Surface of Silica Particles) The cation component in the silica sol was 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. 0.2 g of the obtained powder was put into a polypropylene container (PP sample bottle 50 mL) containing 20 mL of a 0.1 mol / L (N / 10) nitric acid aqueous solution, and shaken vigorously by hand. Next, ultrasonic treatment was performed for 10 minutes with an ultrasonic cleaner (manufactured by AS ONE, product name ASU CLEANER ASU-10M) to sufficiently mix the powder and the nitric acid aqueous solution. It was put into a 50 °C constant temperature bath and held for 17 hours. Thereafter, the internal solution was cooled to room temperature, charged into a centrifugal ultrafiltration filter (product name Amicon Ultra-15, molecular weight cut-off 10,000), and the amount of aluminum in the filtrate obtained by centrifugation was measured with an ICP emission spectrometer. The amount of aluminum bound to the silica particle surface was converted to Al2O3, and the ratio (Al2O3 (ppm) / SiO2) to the mass of SiO2 of the silica was determined.

[0222] (Measurement of the surface charge amount of metal oxide particles) The metal oxide sol was added to and diluted with 10 mL of MeOH so that the metal oxide concentration became 0.5 mass% to obtain a measurement sample. Using a particle charge meter (manufactured by WITT TURBO Co., Ltd., product name PCD-06) and a 0.001 mol / L (N / 1000) DADMAC solution (manufactured by WITT TURBO Co., Ltd.) as a cation standard titrant, the titration value until the streaming potential of the measurement sample became zero was measured. The value obtained by dividing the obtained titration value by the mass of the metal oxide contained in the measurement sample was converted to the value per 1 g of the metal oxide particles and taken as the surface charge amount (μeq / g-SiO2). Note that DADMAC represents poly(diallyldimethylammonium chloride).

[0223] (Elemental analysis of metal oxide particles) For the elemental analysis of the metal oxide particles, a carbon, hydrogen, and nitrogen content (mass%) was measured using an elemental analyzer (manufactured by PerkinElmer, model name: Elemental Analyzer 2400II). The measurement sample was heated at 150 °C to remove adsorbed water.

[0224] (Synthesis Example 1) Synthesis of MeOH dispersion (1) of surface-modified hollow silica particles 200 g of MA-ST-L (trade name, manufactured by Nissan Chemical Industries, Ltd.) was charged into a 500-ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 30 g of MEK and 4.45 g of MPMDMS were added, and the mixture was heated to 60°C and held for 3 hours. Next, 6.61 g of TMSO was added, and the mixture was heated to 60°C and held for 3 hours. Then, DiPA was added so that the pH became 8.3, and the mixture was heated to 60°C and held for 1 hour to obtain the target sol. The obtained methanol dispersion of hollow silica sol using MeOH as the dispersion medium had an average particle diameter of 85 nm by the DLS method, a pH of 9.5, a silica concentration of 35.9% by mass, and a water content of 1.5% by mass. There was no sediment, and it showed good dispersibility.

[0225] (Synthesis Example 2) Synthesis of MEK dispersion (2) of surface-modified hollow silica particles 60.0 g of the MeOH dispersion (1) of the surface-modified silica particles obtained in Synthesis Example 1 was charged into a 200-ml eggplant-shaped flask, set on a rotary evaporator, and distilled while supplying MEK under a reduced pressure of a bath temperature of 80°C and 550 ~350 Torr to replace the dispersion medium with MEK to obtain the target sol. The obtained MEK dispersion of hollow silica sol using MEK as the dispersion medium had an average particle diameter of 80 nm by the DLS method, a pH of 7.6, a silica concentration of 41.6% by mass, a water content of less than 0.1% by mass, and a MeOH content of less than 0.1% by mass. There was no sediment, and it showed good dispersibility.

[0226] (Synthesis Example 3) Synthesis of MEK dispersion (3) of surface-modified hollow silica particles 50 g of MA-ST-L (trade name, manufactured by Nissan Chemical Industries, Ltd.) was charged into a 200-ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 7.5 g of MEK and 1.11 g (unit surface area of the particles (nm 2Corresponding to 3 equivalents of MPDMS molecules, 3 equivalents of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Then, 1.65 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Thereafter, DiPA was added to adjust the pH to 8.4, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was performed while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The obtained MEK-dispersed mesoporous silica sol having MEK as the dispersion medium had an average particle diameter of 79 nm by the DLS method, a pH of 7.3, a silica concentration of 42.7 mass%, a water content of less than 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0227] (Synthesis Example 4) Synthesis of MEK-dispersed solution (4) of surface-modified mesoporous silica particles The target sol was obtained in the same manner as in Synthesis Example 3, except that the amount of MPDMS added in Synthesis Example 3 was changed to 0.74 g (corresponding to 2 equivalents of MPDMS molecules per unit surface area of the particles (nm 2 phase)). The obtained MEK-dispersed mesoporous silica sol having MEK as the dispersion medium had an average particle diameter of 80 nm by the DLS method, a pH of 7.7, a silica concentration of 40.0 mass%, a water content of less than 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0228] (Synthesis Example 5) Synthesis of MEK-dispersed solution (5) of surface-modified mesoporous silica particles The target sol was obtained in the same manner as in Synthesis Example 3, except that the amount of MPDMS added in Synthesis Example 3 was changed to 0.37 g (corresponding to 1 equivalent of MPDMS molecules per unit surface area of the particles (nm 2 equivalent)). The obtained MEK-dispersed mesoporous silica sol having MEK as the dispersion medium had an average particle diameter of 79 nm by the DLS method, a pH of 7.6, a silica concentration of 41.0 mass%, a water content of less than 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0229] (Synthesis Example 6) Synthesis of MEK dispersion (6) of surface-modified hollow silica particles 100 g of MA-ST-L (trade name, manufactured by Nissan Chemical Industries, Ltd.) was charged into a 200-ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 2.0 g of TMSO was added, and the mixture was heated to 60°C and held for 2 hours. Then, the eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 90°C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining a MEK dispersion with a silica concentration of 40.5 mass%. Furthermore, 50 g of the obtained MEK dispersion was charged into a 100-ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 1.3 g of pure water and 1.11 g of MPDMS were added, and the mixture was heated to 60°C and held for 3 hours. Then, DiPEA was added so that the pH became 8.4, and the mixture was heated to 60°C and held for 1 hour to obtain the target sol. The obtained MEK-dispersed hollow silica sol using MEK as the dispersion medium had an average particle diameter of 90 nm by the DLS method, a pH of 5.4, a silica concentration of 40.1 mass%, a water content of 0.1 mass%, and a MeOH content of 0.2 mass%. In addition, there was no sediment, indicating good dispersibility.

[0230] (Synthesis Example 7) Synthesis of MEK dispersion (7) of surface-modified hollow silica particles 50 g of MA-ST-L (manufactured by Nissan Chemical Industries, Ltd., trade name) was charged into a 200 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 7.5 g of MEK and 1.08 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 0.52 g of DTMS was added, and the mixture was heated to 60 °C and held for 3 hours. Then, 1.60 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Thereafter, DiPA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The obtained MEK-dispersed mesoporous silica sol using MEK as the dispersion medium had an average particle diameter of 79 nm by the DLS method, a pH of 7.8, a silica concentration of 39.1 mass%, a water content of less than 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0231] (Synthesis Example 8) Synthesis of Methanol-dispersed Mesoporous Silica (8) 14000 g of Snowtex O-40 (manufactured by Nissan Chemical Industries, Ltd., trade name) was subjected to ultrafiltration using MeOH to replace water, and the replacement was terminated when the water content reached 0.5 mass%, thereby obtaining a MeOH-dispersed mesoporous silica sol. The physical properties of the obtained sol were a silica concentration of 40.6 mass%, a water content of 0.5 mass%, a viscosity of 5.4 mPa·s, an average particle diameter of 56 nm by the DLS method, the amount of Na present in the entire silica particles was 2210 ppm / SiO2 in terms of Na2O relative to the mass of SiO2 of silica, the amount of sulfate ions present in the silica sol was 0.7 ppm / SiO2 in terms of SO4 relative to the mass of SiO2 of silica, and the amount of aluminum present in the entire silica particles was 2500 ppm / SiO2 in terms of Al2O3 relative to the mass of SiO2 of silica.

[0232] (Synthesis Example 9) Synthesis of MEK-dispersed Surface-modified Mesoporous Silica Particles (9) 200 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was charged into a 500 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.27 g of pure water, 30.0 g of MEK, and 9.01 g of MPMDMS were added. The mixture was heated to 60 °C and held for 3 hours. Next, 13.39 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed mesoporous silica sol using MEK as the dispersion medium had an average particle diameter of 39 nm by the DLS method, a pH of 7.7, a silica concentration of 37.6 mass%, a water content of less than 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no precipitate, and it showed good dispersibility.

[0233] (Synthesis Example 10) Synthesis of MEK-dispersed solution (10) of surface-modified mesoporous silica particles 350 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was charged into a 1000 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 9.5 g of pure water, 52.5 g of MEK, and 15.79 g of MPDMS were added. The mixture was heated to 60 °C and held for 3 hours. Next, 23.41 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed mesoporous silica sol using MEK as the dispersion medium had an average particle diameter of 35 nm by the DLS method, a pH of 8.3, a silica concentration of 41.0 mass%, a water content of 0.2 mass%, and a MeOH content of less than 0.1 mass%. There was no precipitate, and it showed good dispersibility.

[0234] (Synthesis Example 11) Synthesis of MEK dispersion (11) of surface-modified hollow silica particles 300 g of MT-ST (trade name, manufactured by Nissan Chemical Industries, Ltd.) was charged into a 1000 ml eggplant-shaped flask. While stirring with a magnetic stirrer, 45.0 g of MEK and 19.60 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The obtained MEK-dispersed hollow silica sol using MEK as the dispersion medium had an average particle diameter of 15 nm by the DLS method, a pH of 9.3, a silica concentration of 30.5 mass%, a water content of 0.1 mass%, and a MeOH content of 0.2 mass%. There was no sediment, and it showed good dispersibility.

[0235] (Synthesis Example 12) Synthesis of PGME dispersion (12) of surface-modified hollow silica particles 300 g of PGM-ST (trade name, manufactured by Nissan Chemical Industries, Ltd.) was charged into a 1000 ml eggplant-shaped flask. While stirring with a magnetic stirrer, 6.2 g of pure water and 19.60 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 38.8 g of TMS was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPEA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour to obtain the target sol. The obtained PGME-dispersed hollow silica sol using PGME as the dispersion medium had an average particle diameter of 19 nm by the DLS method, a pH of 9.1, and a silica concentration of 28.2 mass%. There was no sediment, and it showed good dispersibility.

[0236] (Synthesis Example 13) Synthesis of MeOH dispersion (13) of hollow silica particles 1000 g of ST-ZL (manufactured by Nissan Chemical Industries, Ltd., trade name) was passed through a column filled with a cation exchange resin (manufactured by Dow Chemical Company, trade name: Amberlite IR-120B) at a space velocity of 10 per hour to remove cations, and a silica sol in aqueous dispersion with a pH of 3.3 was obtained. 800 g of the obtained silica sol in aqueous dispersion was charged into a 2-L glass reactor equipped with a stirrer, a condenser, a thermometer, and two inlets. While keeping the sol in the reactor boiling, the vapor of methanol generated by another boiler was continuously blown into the silica sol in the reactor to perform substitution of water with methanol. The substitution was terminated when the volume of the distillate reached 9 L, and 870 g of methanol-dispersed mesoporous silica sol using methanol as a dispersion medium was obtained. The obtained methanol-dispersed silica sol had a silica concentration of 35.7% by mass, a water content of 1.6% by mass, and a pH of 3.0.

[0237] (Synthesis Example 14) Synthesis of MeOH-dispersed solution (14) of surface-modified mesoporous silica particles 400 g of the MeOH-dispersed solution (13) obtained in Synthesis Example 13 was charged into a 1000-ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.8 g of pure water, 60 g of MEK, and 8.49 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Then, 6.3 6 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.3, and the mixture was heated to 60 °C and held for 1 hour. The obtained methanol-dispersed mesoporous silica sol using methanol as a dispersion medium had an average particle diameter of 134 nm by the DLS method, a pH of 8.5, a silica concentration of 27.6% by mass, and a water content of 2.5% by mass. There was no sediment, and it showed good dispersibility.

[0238] (Synthesis Example 15) Synthesis of MEK-dispersed solution (15) of surface-modified mesoporous silica particles The eggplant-shaped flask containing the sol obtained in Synthesis Example 14 was set on a rotary evaporator, and distillation was carried out while supplying MEK under a reduced pressure of a bath temperature of 80 °C and 550 to 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The obtained MEK-dispersed mesoporous silica sol using MEK as the dispersion medium had an average particle diameter of 129 nm by the DLS method, a pH of 6.8, a silica concentration of 28.2 mass%, a water content of 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment and it showed good dispersibility.

[0239] (Synthesis Example 16) Synthesis of MEK-dispersed liquid (16) of surface-modified mesoporous silica particles 400 g of the MeOH-dispersed liquid (13) obtained in Synthesis Example 13 was charged into a 1000 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.8 g of pure water, 60 g of MEK, and 8.49 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 6.36 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, an aqueous sodium hydroxide solution was added so that the pH became 8.3, and the mixture was heated to 60 °C and held for 1 hour. The obtained MEK-dispersed mesoporous silica sol using MEK as the dispersion medium had an average particle diameter of 127 nm by the DLS method, a pH of 8.5, a silica concentration of 28.4 mass%, and a water content of 3.5 mass%. There was no sediment and it showed good dispersibility.

[0240] (Synthesis Example 17) Synthesis of PGME-dispersed liquid (17) of surface-modified mesoporous silica particles 400 g of PGM-ST-ZL (trade name, manufactured by Nissan Chemical Industries, Ltd.) was charged into a 1000 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 8.3 g of pure water and 8.49 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 6.36 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPEA was added so that the pH became 8.0 to 10.0, and the mixture was heated to 60 °C and held for 1 hour. The obtained PGME-dispersed mesoporous silica sol using PGME as the dispersion medium had an average particle diameter of 130 nm by the DLS method and a pH of 6.6. There was no sediment and it showed good dispersibility.

[0241] (Synthesis Example 18) Synthesis of MeOH dispersion (18) of mesoporous silica particles 250 g of Snowtex MSH (trade name, manufactured by Nissan Chemical Industries, Ltd.) was charged into a 300 ml SUS autoclave reactor, and hydrothermal treatment was carried out at 230 ± 10 °C for 2.5 hours. An aqueous sodium sulfate solution diluted to 5% was added to 100 g of the obtained sol so that the SO4 conversion was 20 to 50 ppm, and it was mixed with 30 g of a hydrogen-type strongly acidic cation exchange resin (trade name Amberlite IR-120B). After stirring for 30 minutes, it was filtered to obtain 130 g of acidic silica sol (pH 3, silica concentration 23% by mass, average primary particle diameter 28 nm, Na2O: 344 ppm, SO4 concentration 30 ppm). 130 g of the acidic silica sol obtained above was charged into an evaporator equipped with a 1 L eggplant-shaped flask, and then water was distilled off at 550 Torr while gradually adding MeOH to replace water as the dispersion medium with MeOH. When the water content of this dispersion became 2.0% by mass or less, the replacement was terminated, MeOH was added, and after adjusting to 30 parts by mass, 92 g of the target MeOH-dispersed silica sol (18) was obtained. The obtained methanol-dispersed mesoporous silica sol with methanol as the dispersion medium had an average primary particle diameter of 28.0 nm, a silica concentration of 30.0% by mass, a water content of 1.5% by mass, a viscosity of 5.4 mPa·s, an average particle diameter of 48 nm by the DLS method, the amount of Na present in the entire silica particles was 1700 ppm / SiO2 in terms of Na2O relative to the mass of SiO2 of silica, and the amount of sulfate ions present in the silica sol was 36 ppm / SiO2 in terms of SO4 relative to the mass of SiO2 of silica. Also, the amount of aluminum present in the entire silica particles was 470 ppm / SiO2 in terms of Al2O3 relative to the mass of SiO2 of silica.

[0242] (Synthesis Example 19) Synthesis of MeOH dispersion (19) of surface-modified mesoporous silica particles 50 g of the MeOH-dispersed silica sol (18) obtained in Synthesis Example 18 was charged into a 100 ml eggplant flask equipped with a condenser, and while stirring with a magnetic stirrer, 0.78 g of pure water and 1.32 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 1.97 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPEA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour. The obtained methanol-dispersed mesoporous silica sol using methanol as the dispersion medium had an average particle diameter of 63 nm and a pH of 7.2 by the DLS method. There was no sediment, and it showed good dispersibility.

[0243] (Synthesis Example 20) Synthesis of MeOH-dispersed hollow silica sol (20) 1856 g of HKT-A20-40D (manufactured by Ningbo Dilato, trade name) was placed in a 3 L plastic container, and 32.2 g of sodium aluminate diluted to a concentration of 1.0 mass% in terms of Al2O3 was added dropwise over 1 minute. Further, 643.6 g of pure water was added, and the mixture was stirred at a rotational speed of 600 rpm for 30 minutes using a mechanical stirrer equipped with a glass stirring blade. Next, 2442 g of this mixture was placed in a SUS autoclave container, and heat treatment was performed at 150 °C for 5 hours and then cooled to room temperature. To 1700 g of the obtained heat-treated aqueous dispersion silica sol, 1.51 g of an 8.2% sulfuric acid aqueous solution was added dropwise, and the mixture was stirred at a stirring speed of 800 rpm at room temperature for 1 hour to obtain a sulfuric acid-added heat-treated aqueous dispersion silica sol. Next, it was passed through a column-packed cation exchange resin (trade name H-type Amberlite IR-120B) at a space velocity (SV) of 5 / hour to obtain an aqueous dispersion sol (20-1) of aluminum-containing hollow silica particles. As a result of measuring the physical properties of the obtained aqueous dispersion sol (20-1), 14.3 mass% as SiO2, pH 2.5, average particle diameter of 54 nm by the DLS method, specific surface area (C) of 149 m 2 / g, the amount of aluminum bound to the particle surface (A) was 1500 ppm, the amount of aluminum present in the entire silica particles (B) was 1900 ppm in terms of Al2O3 as a ratio to the mass of SiO2 of silica, (A / B ratio) was 0.79, the average primary particle diameter by TEM observation was 43 nm, and the BET specific surface area (D) was 123 m 2 / g, the refractive index of the particles was 1.26, and the thickness of the outer shell was 6.7 nm. Subsequently, the obtained aqueous dispersion sol (20-1) was heat-treated at 80 °C for 10 hours, cooled to room temperature, and then passed through a column-packed cation exchange resin (trade name: H-type Amberlite IR-120B) at a space velocity (SV) of 5 / hour to obtain an aqueous dispersion sol (20-2) of aluminum-containing hollow silica particles. Its physical properties were as follows: silica concentration 14.0 mass%, pH 2.3, average particle diameter by DLS method 54 nm, specific surface area (C) by BET method 116 m 2 / g, the amount of aluminum bound to the particle surface (A) was 1500 ppm, the amount of aluminum present in the whole particle (B) was 2500 ppm, the (A / B ratio) was 0.60, the average primary particle diameter by TEM observation was 43 nm, and the specific surface area (D) in terms of TEM was 63 m 2 / g, the specific surface area ratio (C / D ratio) was 1.8, the refractive index of the particles was 1.27, and the thickness of the outer shell was 6.0 nm. Subsequently, the eggplant-shaped flask containing the obtained aqueous dispersion sol (20-2) was set on a rotary evaporator, and distilled while supplying MeOH under reduced pressure of a bath temperature of 120 °C and 580 Torr to replace the dispersion medium with MeOH, thereby obtaining the target sol. The obtained methanol-dispersed hollow silica sol with methanol as the dispersion medium had an average particle diameter of 72 nm by the DLS method, a pH of 3.1, a silica concentration of 20.3 mass%, and a water content of 1.2 mass% It was. There was no sediment and it showed good dispersibility.

[0244] (Synthesis Example 21) Synthesis of MEK dispersion liquid (21) of surface-modified hollow silica particles 50 g of the MeOH-dispersed hollow silica sol (20) obtained in Synthesis Example 20 was charged into a 100 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 0.4 g of pure water, 7.5 g of MEK, and 0.60 g of MPDMS were added, and heated to 60 °C and held for 3 hours. Then, 0.87 g of TMSO was further added, and heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.0, and heated to 60 °C and held for 1 hour. Subsequently, the eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under a reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed hollow silica sol using the obtained MEK as the dispersion medium had an average particle diameter of 66 nm by the DLS method, a pH of 7.1, a silica concentration of 19.1 mass%, a water content of 0.2 mass%, and a MeOH content of less than 0.1 mass%. There was no precipitate and it showed good dispersibility.

[0245] (Synthesis Example 22) Synthesis of MEK-dispersed solution (22) of surface-modified hollow silica particles 50 g of the MeOH-dispersed hollow silica sol (20) obtained in Synthesis Example 20 was charged into a 100 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 0.95 g of pure water, 7.5 g of MEK, and 0.54 g of MPMDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Then, 0.79 g of TMSO was further added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.0, and the mixture was heated to 60 °C and held for 1 hour. Subsequently, the eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under a reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed hollow silica sol using the obtained MEK as the dispersion medium had an average particle diameter of 66 nm by the DLS method, a pH of 7.1, a silica concentration of 12.8 mass%, a water content of 0.1 mass%, and a MeOH content of 0.2 mass%. There was no precipitate and it showed good dispersibility.

[0246] (Synthesis Example 23) Synthesis of MEK-dispersed solution (23) of surface-modified solid silica particles 1,000 g of MA-ST-L was charged into a 2-liter eggplant-shaped flask, and while stirring with a magnetic stirrer, 150 g of MEK and 21.6 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour. Subsequently, the eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under a reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed mesoporous silica sol using the obtained MEK as the dispersion medium had an average particle diameter of 86 nm by the DLS method, a pH of 7.6, a silica concentration of 38.9 mass%, a water content of less than 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment and it showed good dispersibility.

[0247] (Synthesis Example 24) Synthesis of MEK-dispersed solution (24) of surface-modified mesoporous silica particles 1,000 g of MA-ST-L was charged into a 2-liter eggplant-shaped flask, and while stirring with a magnetic stirrer, 150 g of MEK and 32.0 g of TMSO were added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.4, and the mixture was heated to 60 °C and held for 1 hour. Subsequently, the eggplant-shaped flask containing the obtained sol was set on a rotary evaporator and distillation was carried out while supplying MEK under a reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed mesoporous silica sol using the obtained MEK as the dispersion medium had an average particle diameter of 87 nm by the DLS method, a pH of 7.8, a silica concentration of 33.4 mass%, a water content of less than 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment and it showed good dispersibility.

[0248] (Synthesis Example 25) Synthesis of MEK-dispersed solution (25) of surface-modified mesoporous silica particles 200 g of the MeOH-dispersed silica sol (8) obtained in Synthesis Example (8) was charged into a 500-ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.2 g of pure water and 9.79 g of PTMS were added. The mixture was heated to 60 °C and held for 2 hours. Then, DiEPA was added so that the pH became 7.9, and the mixture was heated to 60 °C and held for 2 hours. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out under reduced pressure of 550 - 350 Torr at a bath temperature of 80 °C while supplying MEK, and the dispersion medium was replaced with MEK to obtain the target MEK-dispersed mesoporous silica sol having MEK as the dispersion medium. The average particle diameter by the DLS method was 32.7 nm, pH was 7.4, silica concentration was 40.7 mass%, water content was 0.2 mass%, and MeOH content was 0.4 mass%. There was no sediment, and good dispersibility was shown.

[0249] (Synthesis Example 26) Synthesis of MeOH-dispersed solution (26) of surface-modified silica particles 50 g of the MeOH-dispersed silica sol (18) obtained in Synthesis Example 18 was charged into a 100-ml eggplant flask equipped with a condenser, and while stirring with a magnetic stirrer, 0.25 g of MTMS was added. The mixture was heated to 60 °C and held for 3 hours to obtain the target silica sol. The obtained methanol-dispersed mesoporous silica sol having methanol as the dispersion medium had an average particle diameter of 48 nm and a pH of 3.1 by the DLS method. There was no sediment, and good dispersibility was shown.

[0250] (Synthesis Example 27) MA-ST-L (trade name, manufactured by Nissan Chemical Industries, Ltd.) was prepared as the MeOH-dispersed silica sol (27) having methanol as the dispersion medium for surface-unmodified silica particles.

[0251] (Synthesis Example 28) Synthesis of MeOH-dispersed silica sol (28) 100 g of PL-3 (manufactured by Fuso Chemical Industry Co., Ltd., trade name) was placed in an evaporator equipped with a 500 mL eggplant-shaped flask, and then water was distilled off at 580 Torr while gradually adding MeOH, thereby replacing water, which is the dispersion medium, with MeOH. When the water content of this dispersion liquid reached 2.0 mass% or less, the replacement was terminated. After adding MeOH and adjusting so that the silica particle concentration became 30 mass parts, 100 g of MeOH-dispersed silica sol (a3) was obtained. The obtained MeOH-dispersed silica sol using methanol as the dispersion medium had a silica concentration of 30.0 mass%, an average particle diameter of 69.1 nm by the DLS method, the amount of Na present in the entire silica particles was 2210 ppm / SiO2 in terms of Na2O relative to the mass of SiO2 of silica, and the amount of sulfate ions present in the silica sol was 0.7 ppm / SiO2 in terms of SO4 relative to the mass of SiO2 of silica. Also, the amount of aluminum present in the entire silica particles was 0.026 ppm / SiO2 in terms of Al2O3 relative to the mass of SiO2 of silica.

[0252] (Synthesis Example 29) Synthesis of Polysiloxane (P1) 14.58 g of TEOS (70 mol% in all silane compounds), 3.57 g of MTMS (20 mol% in all silane compounds), 1.98 g of PTMS (10 mol% in all silane compounds), and 31 g of acetone were placed in a 200 ml flask, and the mixed solution was stirred with a magnetic stirrer. Here, 6.67 g of 0.01 mol / L hydrochloric acid was added dropwise. After the addition, the flask was transferred to an oil bath adjusted to 85 °C and reacted for 240 minutes under heating and reflux. Then, the reaction solution was cooled to room temperature, 40 g of PGMEA was added to the reaction solution, and methanol, ethanol, water, and hydrochloric acid, which are reaction by-products, were distilled off under reduced pressure and concentrated to obtain a PGMEA solution of a hydrolysis condensate (polymer, formula d-1) having the following unit structure. PGEE was added here, and solvent replacement was performed by distilling off the solvent to obtain a PGEE polymer solution. The obtained solution was adjusted with PGEE so that it became 15 mass% in terms of solid residue at 200 °C. Also, the weight average molecular weight (Mw) of the obtained polymer was 1,500 in terms of polystyrene. [Chemical formula]

[0253] (Synthesis Example 30) Preparation of Polyamic Acid (P2) 4,4'-Diaminodiphenyl Ether (DDE) and pyromellitic dianhydride (PMDA) were polymerized at 50 °C with stirring using NMP and DMAC as solvents to obtain a polyamic acid corresponding to formula (e-1) (solid content 17% by mass, viscosity at 25 °C of 13640 mPa·s measured with an E-type viscometer). The polyamic acid was polymerized with DDE and PMDA in an equimolar ratio of 1:1. The weight average molecular weight of the obtained polyamic acid was 63000. In formula (e-1), n is the number of repeating units. [Chemical formula]

[0254] (Synthesis Example 31) Synthesis of Polyimide (P3) Into a 250 mL three-necked reaction flask equipped with a nitrogen inlet / outlet, a mechanical stirrer and a cooler, 25.6 g (0.08 mol) of 2,2'-bis(trifluoromethyl)benzidine was placed. Then, 173 g of GBL was added and stirring was started. Immediately after the diamine was completely dissolved in the solvent, 10.0 g (4 mmol) of stirred bicyclo[2,2,2]octane-2,3,5,6-tetracarboxylic dianhydride, 7.84 g (4 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 43.4 g of GBL were added, and the mixture was heated to 140 °C under nitrogen. Then, 0.35 g of 1-ethylpiperidine was added to the solution, and the mixture was heated to 180 °C for 7 hours under nitrogen. Finally, heating was stopped, the reaction solution was diluted to 10% by mass, and stirring was maintained overnight. The obtained polyimide reaction solution was added to 2000 g of a GBL:MeOH = 50% by mass:50% by mass mixed solution and stirred for 30 minutes, and then the polyimide solid was filtered to purify the polyimide. Then, the polyimide solid was stirred in 2000 g of MeOH for 30 minutes, and the polyimide solid was filtered. This purification procedure of stirring and filtering the polyimide solid was repeated 3 times. The MeOH residue in the polyimide was removed by drying in a vacuum oven at 150 °C for 8 hours, and finally, 21.5 g of dried polyimide (P3) was obtained. The obtained polyimide contained the unit structures of formula (f-1) and formula (f-2). The yield of P3 was 51% (Mw = 310,000, number average molecular weight (Mn) = 144,300). [Chemical formula]

[0255] (Synthesis Example 32) Synthesis of MeOH dispersion (32) of surface-modified mesoporous silica particles 300 g of MT-ST (manufactured by Nissan Chemical Industries, Ltd., trade name) was charged into a 1000 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 45.0 g of MEK and 19.60 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPEA was added so that the pH became 8.6, and the mixture was heated to 60 °C and held for 1 hour. The obtained methanol-dispersed mesoporous silica sol using methanol as a dispersion medium had an average particle diameter of 22 nm by the DLS method, a pH of 8.2, a silica concentration of 25.0 mass%, and a water content of 2.2 mass%. There was no sediment, indicating good dispersibility.

[0256] (Synthesis Example 33) Synthesis of MEK-dispersed solution (33) of surface-modified mesoporous silica particles 300 g of MT-ST (manufactured by Nissan Chemical Industries, Ltd., trade name) was charged into a 1000 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 45.0 g of MEK and 19.60 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPEA was added so that the pH became 8.2, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The obtained MEK-dispersed mesoporous silica sol using MEK as a dispersion medium had an average particle diameter of 19 nm by the DLS method, a pH of 7.6, a silica concentration of 30.8 mass%, a water content of 0.2 mass%, and a MeOH content of 0.1 mass%. There was no sediment, indicating good dispersibility.

[0257] (Synthesis Example 34) Synthesis of MEK-dispersed solution (34) of surface-modified mesoporous silica particles 300 g of MT-ST (manufactured by Nissan Chemical Industries, Ltd., trade name) was charged into a 1000 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 45.0 g of MEK and 23.63 g of MPMDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPEA was added so that the pH became 7.9, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under a reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed mesoporous silica sol using the obtained MEK as the dispersion medium had an average particle diameter of 20 nm by the DLS method, a pH of 7.3, a silica concentration of 31.0 mass%, a water content of 0.2 mass%, and a MeOH content of 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0258] (Synthesis Example 35) Synthesis of MEK-dispersed solution (35) of surface-modified mesoporous silica particles 200 g of the MeOH-dispersed solution (8) obtained in Synthesis Example 8 was charged into a 500 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.27 g of pure water, 30.0 g of MEK, and 8.99 g of MPDMS were added, and the mixture was heated to 60 °C and held for 3 hours. Next, 13.39 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPEA was added so that the pH became 7.7, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under a reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The MEK-dispersed mesoporous silica sol using the obtained MEK as the dispersion medium had an average particle diameter of 33 nm by the DLS method, a pH of 7.1, a silica concentration of 39.9 mass%, a water content of 0.2 mass%, and a MeOH content of 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0259] (Synthesis Example 36) Synthesis of MEK-dispersed solution (36) of surface-modified mesoporous silica particles 200 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was charged into a 500 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 5.27 g of pure water, 30.0 g of MEK, and 12.01 g of MPMDMS were added. The mixture was heated to 60 °C and held for 3 hours. Then, 13.39 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Thereafter, DiPEA was added so that the pH became 7.7, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The obtained MEK-dispersed mesoporous silica sol having MEK as the dispersion medium had an average particle diameter of 33 nm by the DLS method, a pH of 7.1, a silica concentration of 39.9 mass%, a water content of 0.2 mass%, and a MeOH content of 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0260] (Synthesis Example 37) Synthesis of MEK-dispersed mesoporous silica particles with surface modification (37) 300 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was charged into a 500 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 7.5 g of pure water, 45.0 g of MEK, and 19.87 g of DEDPS were added. The mixture was heated to 60 °C and held for 3 hours. Then, 19.77 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Thereafter, DiPEA was added so that the pH became 7.8, and the mixture was heated to 60 °C and held for 1 hour. The eggplant-shaped flask containing the obtained sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium with MEK, thereby obtaining the target sol. The obtained MEK-dispersed mesoporous silica sol having MEK as the dispersion medium had an average particle diameter of 29 nm by the DLS method, a pH of 7.2, a silica concentration of 40.7 mass%, a water content of 0.1 mass%, and a MeOH content of less than 0.1 mass%. There was no sediment, and it showed good dispersibility.

[0261] (Synthesis Example 38) Synthesis of MEK-dispersed hollow silica sol (38) Except for using HKT-A20-70D instead of HKT-A20-40D in Synthesis Example 20, an aluminum atom-containing hollow silica particle (average primary particle diameter of 71 nm by TEM observation, BET specific surface area (D) of 102 m 2 / g) MeOH-dispersed silica sol was obtained in the same process as in Synthesis Example 20. 50 g of the obtained MeOH-dispersed silica sol of aluminum atom-containing hollow silica particles was charged into a 100 mL plastic container, and 50 ml of a cation exchange resin (manufactured by Dow Chemical Co., trade name: Amberlite IR-120B) was added, and it was held for 60 minutes while stirring at 100 revolutions per minute with a mix rotor (manufactured by AS ONE Corporation, trade name: MIX-ROTAR MR-5) to obtain a MeOH-dispersed silica sol of hollow silica particles. Next, 25 g of the obtained MeOH-dispersed silica sol of hollow silica particles was charged into a 50 mL eggplant flask, and while stirring with a magnetic stirrer, 3.8 g of MEK, 0.16 g of a 10 mass% MeOH solution of MEHQ diluted with MeOH, and 0.20 g of MPDMS were added, and it was heated to 60 °C and held for 3 hours. Then, 0.29 g of TMSO was added, and it was heated to 60 °C and held for 3 hours. Thereafter, DiPA was added so that the pH became 8.0 to 10.0, and it was heated to 60 °C and held for 1 hour to obtain a MeOH-dispersed silica sol of surface-modified hollow silica particles. The eggplant-shaped flask containing the obtained silica sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure at a bath temperature of 80 °C and 550 to 350 Torr to replace the dispersion medium from MeOH to MEK, thereby obtaining a MEK-dispersed silica sol of hollow silica particles. The obtained MEK-dispersed silica sol had an average primary particle diameter of 71 nm by TEM, a specific surface area (D) of 38 m 2 / g by TEM, an average particle diameter of 105 nm by the DLS method, a pH of 6.2, a solid content (silica particles) concentration of 30.1 mass%, a water content of 0.3 mass%, and less than 0.1 mass% of MeOH. The obtained hollow silica sol showed good dispersibility without sediment.

[0262] (Synthesis Example 39) Synthesis of MEK-dispersed hollow silica sol (39) 100 g of the MeOH-dispersed hollow silica sol (20) obtained in Synthesis Example 20 was charged into a 250 mL plastic container, 10 mL of a cation exchange resin (manufactured by Dow Chemical Co., trade name: Amberlite IR-120B) was added, and the mixture was held for 60 minutes while stirring at 100 revolutions per minute with a mix rotor (manufactured by AS ONE Corporation, trade name: MIX-ROTAR MR-5) to obtain a MeOH-dispersed silica sol of hollow silica particles. Next, 55 g of the MeOH-dispersed silica sol of the obtained hollow silica particles was charged into a 300 mL eggplant flask, 0.01 g of MEHQ and 0.50 g of APMDMS were added while stirring with a magnetic stirrer, and the mixture was heated to 60 °C and held for 3 hours. Then, 1.29 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. Then, DiPA was added so that the pH became 8.0, and the mixture was heated to 60 °C and held for 1 hour to obtain a MeOH-dispersed silica sol of surface-modified hollow silica particles. The eggplant-shaped flask containing the obtained silica sol was set on a rotary evaporator, and distillation was carried out while supplying MEK under reduced pressure of a bath temperature of 80 °C and 550 - 350 Torr to replace the dispersion medium from MeOH to MEK, thereby obtaining a MEK-dispersed silica sol of hollow silica particles. The obtained MEK-dispersed silica sol had an average primary particle diameter of 40 nm by TEM, an average particle diameter of 62 nm by the DLS method, a pH of 7.4, a viscosity of 1.4 mPa·s, a solid content (silica particles) concentration of 21.6 mass%, a water content of 0.4 mass%, and less than 0.1 mass% of MeOH. The obtained hollow silica sol showed good dispersibility without any sediment.

[0263] (Synthesis Example 40) Synthesis of MeOH dispersion of surface-modified solid silica particles (40) 300 g of MT-ST (manufactured by Nissan Chemical Industries, Ltd., trade name) was charged into a 1000 mL eggplant flask, 45.0 g of MEK and 19.60 g of MPDMS were added while stirring with a magnetic stirrer, and the mixture was heated to 60 °C and held for 3 hours. Then, 29.03 g of TMSO was added, and the mixture was heated to 60 °C and held for 3 hours. The obtained MeOH-dispersed mesoporous silica sol with MeOH as the dispersion medium had an average particle diameter of 21 nm by the DLS method, a silica concentration of 25.1 mass%, and a water content of 2.1 mass%. There was no sediment, indicating good dispersibility.

[0264] (Synthesis Example 41) Synthesis of MeOH-dispersed solution (41) of surface-modified mesoporous silica particles 50 g of the MeOH-dispersed hollow silica sol (20) obtained in Synthesis Example 20 was charged into a 100 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 7.5 g of MEK and 0.83 g of MTMS were added, and the mixture was heated to 60 °C and held for 3 hours. The obtained MeOH-dispersed hollow silica sol with methanol as the dispersion medium had an average particle diameter of 73 nm by the DLS method, a pH of 3.3, a silica concentration of 17.2 mass%, and a water content of 1.0 mass%. There was no sediment, indicating good dispersibility.

[0265] (Synthesis Example 42) Synthesis of MEK-dispersed hollow silica sol (42) A MEK-dispersed hollow silica sol was synthesized in the same manner as in Synthesis Example 38, except that MPMDMS was added instead of MPDMS in Synthesis Example 38. The obtained MEK-dispersed silica sol had an average primary particle diameter of 71 nm by TEM, an average particle diameter of 109 nm by the DLS method, a pH of 6.5, a solid content (silica particles) concentration of 30.3 mass%, a water content of 0.4 mass%, and less than 0.1 mass% of MeOH. The obtained hollow silica sol had no sediment and showed good dispersibility.

[0266] (Evaluation of preparation of high-concentration sol by redispersion of dry powder) Example 1-1: A 100-ml eggplant-shaped flask containing 50 g of the sol obtained in Synthesis Example 1 was set on a rotary evaporator, and the dispersion solvent was removed under reduced pressure at a bath temperature of 60 to 80 °C and 20 to 50 Torr to obtain a dried product of the sol. Further, the obtained dried product was crushed with a mortar and pestle to obtain a powder of silica particles. Then, 1.20 g of the obtained powder of silica particles was charged into a 13-ml glass vial, and an organic solvent described in Tables 1 to 6 was added so that the metal oxide concentration having a refractive index of 1.4 to 3.0 was 60% by mass or more, or the metal oxide concentration having a refractive index of less than 1.1 to 1.4 was 30% by mass or more. Next, it was stirred for 12 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). If the appearance of the obtained mixture had transparency, it was considered redispersible; if the appearance was opaque (cloudy due to aggregation), had no fluidity, or if powder remained, it was considered non-redispersible. Further, DLS after redispersion of the powder of silica particles that was redispersible was obtained. In the table, when it was redispersible, "OK" was described; when it was non-redispersible, "NG" was described; and when not implemented, "-" was described as the result. Further, from the DLS measurement results after redispersion, the DLS ratio before and after redispersion: (average particle diameter by the DLS method in the high-concentration sol) / (average particle diameter by the DLS method of the silica particles before removing the organic solvent) was described. Examples 1-2 to 1-22, Examples 1-25 to 1-30, Examples 1-33 to 1-35: Dried powders of the sols obtained in Synthesis Examples 2 to 19, Synthesis Examples 32 to 37 were prepared in the same manner as in Example 1-1, mixed with the organic solvents described in Tables 1 to 6, and the redispersibility was confirmed. The obtained redispersibility results and the DLS measurement results after redispersion are described in Tables 1 to 6. Examples 1-23 to 1-24, Examples 1-31, 1-32, 1-36: Dried powders of the sols obtained in Synthesis Examples 21 to 22, Synthesis Examples 38 to 39, 42 were prepared in the same manner as in Example 1, except that the organic solvents described in Table 1 were added so that the solid content was 30% by mass or more, mixed with the organic solvents described in Tables 1 to 6, and the redispersibility was confirmed. The obtained redispersibility results and the DLS measurement results after redispersion are described in Tables 1 to 6. Comparative Examples 1-1 to 1-7: The dry powders of the sols obtained in Synthesis Examples 23 to 27, Synthesis Example 40, and Synthesis Example 41 were prepared in the same manner as in Example 1-1, mixed with the organic solvents described in Tables 1 to 6, and the redispersibility was confirmed. The obtained redispersibility results and the DLS measurement results after redispersion are shown in Tables 1 to 6. Representative examples showing the sol appearance after confirmation of redispersibility are shown in Fig. 4. In Fig. 4, the left shows Example 1-3 which was redispersible, and the right shows Comparative Example 1-2 which was not redispersible.

[0267]

Table 1

[0268]

Table 2

[0269]

Table 3

[0270]

Table 4

[0271]

Table 5

[0272]

Table 6

[0273] From the above results, the hydrolyzates of the silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2) and the hydrolyzates of the silane compound (B) having three chemical groups (b1) and one hydrolyzable group (b2) were surface-coated and contained the basic compound (I). Examples 1-1 to 1-36 showed high redispersibility in organic solvents and high-concentration characteristics. On the other hand, among the above silane compounds (A) and (B), Comparative Examples 1-1 to 1-4 and 1-7, in which only one of the hydrolyzates was surface-coated and contained or did not contain the basic compound (I), did not show redispersibility in organic solvents and did not show high-concentration characteristics. Or, Comparative Example 1-6, in which the hydrolyzate of the silane compound (A) and the hydrolyzate of the silane compound (B) were surface-coated and did not contain the basic compound (I), did not show redispersibility in organic solvents and did not show high-concentration characteristics.

[0274] (Evaluation of Preparation of High-Concentration Sol by Solvent Substitution or Concentration) Example 2-1: A 50 ml eggplant-shaped flask containing 20 g of the sol obtained in Synthesis Example 3 was set on a rotary evaporator, and MEK was distilled off under a reduced pressure of 400 Torr at a bath temperature of 80 °C to obtain a high-concentration sol with a metal oxide concentration of 60% by mass. The obtained high-concentration sol showed good dispersibility without any sediment. The obtained results are described in Tables 7 to 8. From the DLS measurement results after concentration, the DLS ratio before and after concentration: (average particle diameter by the DLS method in the high-concentration sol) / (average particle diameter by the DLS method of the silica particles before removing the organic solvent) was described. Example 2-2: A 50 ml eggplant-shaped flask containing 20 g of the sol obtained in Synthesis Example 21 was set on a rotary evaporator, and MEK was distilled off while supplying PGMEA under a reduced pressure of 400 Torr at a bath temperature of 80 °C. While substituting the dispersion medium with PGMEA, the sol was concentrated to obtain a sol with a silica concentration of 40% by mass or more. The obtained sol showed good dispersibility without any sediment. The obtained results are described in Tables 7 to 8. From the DLS measurement results after concentration, the DLS ratio before and after concentration: (average particle diameter by the DLS method in the high-concentration sol) / (average particle diameter by the DLS method of the silica particles before removing the organic solvent) was described. In Table 8, OK in the determination indicates that redispersion is possible, while NG indicates that redispersion is not possible.

[0275]

Table 7

[0276]

Table 8

[0277] (Storage Stability Test) Example 3-1: 2 g of the sol obtained in Example 1-3 was sealed in a 13-ml glass vial and stored at 50 °C for 4 weeks to confirm the storage stability at 50 °C. The average particle diameter by the DLS method after 4 weeks at 50 °C was 86 nm, confirming that it had high storage stability. The results obtained are shown in Tables 9 to 10. Example 3-2: The storage stability was confirmed in the same manner as described in Example 3-1, except that the sol obtained in Example 1-23 was used instead of the sol obtained in Example 1-3. The average particle diameter by the DLS method after 4 weeks at 50 °C was 78 nm, and it was confirmed that it had high storage stability. The results obtained are shown in Tables 9 to 10. Example 3-3: The storage stability was confirmed in the same manner as described in Example 3-1, except that the sol obtained in Example 2-2 was used instead of the sol obtained in Example 1-3. The average particle diameter by the DLS method after 4 weeks at 50 °C was 71 nm, and it was confirmed that it had high storage stability. The results obtained are shown in Tables 9 to 10.

[0278]

Table 9

[0279]

Table 10

[0280] (Particle surface state, redispersibility, and high-concentration characteristics of metal oxide particles) Example 4-1: 8 ml of the sol obtained in Synthesis Example 2 was placed in a 42-ml pear-shaped precipitation tube (manufactured by Thermo Fisher Scientifics, product name: Nalgene Oak Ridge), 8 ml of MEK and 20 ml of hexane were added, and cloudiness, separation, or precipitation due to aggregation was caused. Then, centrifugation (temperature: 5°C, rotation speed: 5000 rpm, time: 30 minutes) was performed using a centrifuge (manufactured by Tomy Seiko Co., Ltd., product name: High-Speed Cooling Centrifuge Suprema 21), and then the supernatant was removed. Then, 4 ml of acetone was added, and the precipitate obtained by centrifugation was redissolved with a test tube mixer (manufactured by AS ONE Corporation, product name: MVM-10), and then 20 mL of hexane was added. Then, after centrifugation, the supernatant was removed. Then, 4 ml of acetone was added, and the precipitate obtained by centrifugation was redissolved with a test tube mixer, and then 20 mL of hexane was added. Then, after centrifugation, the supernatant was removed. The obtained mixture was vacuum dried (temperature: 60°C, gauge pressure of Bourdon tube vacuum gauge -0.1 MPa: in terms of absolute pressure (atmospheric pressure + gauge pressure), 0.1013 MPa - 0.1 MPa = 1.3 kPa), and the obtained powder was pulverized in a mortar to obtain silica particles. The elemental analysis measurement results of the obtained silica particles and 29 the Si-NMR measurement results are shown in Tables 11 to 12. 29 In the Si-NMR structural analysis, (A) shows an integral value ratio of 90 to 100 mol%, (B) shows an integral value ratio of less than 60 to 90 mol%, (C) shows an integral value ratio of less than 30 to 60 mol%, (D) shows an integral value ratio of less than 0.1 to 30 mol%, and (E) shows no integral value ratio (no detection signal). Furthermore, the redispersibility and high-concentration characteristics of the obtained silica particles were evaluated. For the evaluation of redispersibility and high concentration, 1.20 g of the powder of the obtained silica particles was placed in a 13-ml glass vial, and PGMEA was added so that the metal oxide concentration would be 60% by mass or more. Then, using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5), 12 It was stirred for a certain time. If the appearance of the obtained mixture was transparent, it was considered redispersible; if the appearance was opaque or powder remained, it was considered non-redispersible. The results were recorded in the table as "OK" when redispersible and "NG" when non-redispersible. Examples 4-2 to 4-6: Powders of silica particles of Synthesis Example 3, Synthesis Example 4, Synthesis Example 6, Synthesis Example 9, and Synthesis Example 11 were prepared in the same manner as in Example 4-1. Further, in the same manner as in Example 4-1, the surface state, redispersibility, and high-concentration property of the obtained silica particles were confirmed. The obtained results are shown in Tables 11 to 12. Comparative Examples 4-1 to 4-3: Powders of silica particles of Synthesis Example 23, Synthesis Example 24, and Synthesis Example 27 were prepared in the same manner as in Example 4-1. Further, in the same manner as in Example 4-1, except that PGMEA was added so that the metal oxide concentration was 41% by mass or more instead of adding PGMEA so that the solid content was 60% by mass or more, the surface state, redispersibility, and high-concentration property of the obtained silica particles were confirmed. The obtained results are shown in Tables 11 to 12.

[0281]

Table 11

[0282]

Table 12

[0283] From the above results, the silane compound on the surface of the metal oxide particles 29 In the measurement of Si-NMR, when the total of the M structure, D structure, and T structure is 100 mol%, the content ratio of each structure of the M structure, D structure, and T structure is such that the M structure is 30 mol% or more and less than 60 mol%, the D structure is 30 mol% or more and less than 90 mol%, and the T structure is 0 mol% or more and less than 30 mol%. Examples 4-1 to 4-7 showed high redispersibility in organic solvents and high-concentration properties. On the other hand, the silane compound on the surface of the metal oxide particles 29In the measurement of Si-NMR, in Comparative Example 4-1 where the content ratio of each of the M structure, D structure, and T structure is such that when the total of the M structure, D structure, and T structure is 100 mol%, the D structure is 90 mol% or more and the M structure does not exist, Comparative Example 4-2 where the M structure is 90 mol% or more and the D structure does not exist, and Comparative Example 4-3 that does not contain any structure selected from the M structure, D structure, and T structure, did not show redispersibility in an organic solvent and did not show high-concentration characteristics.

[0284] (Evaluation of polysiloxane composition) Example 5-1: An eggplant flask containing a solution obtained by mixing the polymer of Synthesis Example 29 and the silica sol obtained in Synthesis Example 21 at a solid content ratio of 50:50 was placed in an evaporator, and MeOH was distilled off at a bath temperature of 80 °C and 250 Torr to prepare the target composition described in Tables 13 to 14. After measuring the concentration, it was applied onto a 5 × 5 cm alkali-free glass substrate (manufactured by Corning, product name: Eagle XG) set on a spin coater (manufactured by Mikasa Co., Ltd., product name: MS-A100) under film formation conditions of 800 rpm × 5 seconds. Then, after baking on a hot plate at 100 °C for 2 minutes and further baking at 180 °C for 30 minutes, a coating film was obtained. The obtained coating film was transparent, and as a result of measuring the total light transmittance (T.T.) with a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name: NHD-5000), it was 93.3%. Also, the film thickness was measured with the product name F20-EXR (manufactured by FILMETRICS Co., Ltd.) and was 1.603 μm. The conditions and the obtained results are shown in Tables 13 to 14. A photograph of the obtained film is shown in Figure 1. Comparative Example 5-1: The same procedure as in Example 5-1 was carried out except that the sol used was changed to MeOH-dispersed silica sol (28). The film obtained after baking had cracks, and the target coating film could not be obtained. The conditions and the obtained results are shown in Tables 13 to 14. A photograph of the film obtained in Comparative Example 5-1 is shown in Figure 2. The film-forming property was evaluated according to the following criteria (A), (B), and (C). The results are shown in Table 13. (A): Film formation of 1.5 μm or more was possible, (B): Film formation of more than 1 μm to less than 1.5 μm was possible, (C): Film formation of 1 μm or less was impossible.

[0285]

Table 13

[0286]

Table 14

[0287] From the above results, the hydrolyzate of MPDMS as the silane compound (A) having two organic functional chemical groups (a1) and two hydrolyzable groups (a2), and the hydrolyzate of TMSO as the silane compound (B) having three organic functional chemical groups (b1) and one hydrolyzable group (b2) were surface-coated, and the silica particles containing DiPA as the basic compound (I) showed high compatibility with the resin, and a coating film was obtained. On the other hand, when metal oxide particles containing aluminum atoms at a ratio (A) of 100 to 20,000 ppm / metal oxide with respect to the mass of the metal oxide in terms of Al2O3 were not included on the surface of the metal oxide particles by measurement by the leaching method, the target coating film could not be obtained.

[0288] (Maleimide Resin Composition Evaluation) Example 6-1: Regarding the surface-modified silica particles obtained in Synthesis Example 1-3, the compatibility between the surface-modified silica particles and an organic resin material (maleimide resin) was confirmed. 50 g of the MEK dispersion of the surface-modified silica particles obtained in Synthesis Example 1-3 was charged into a 300 mL eggplant-shaped flask, and while stirring with a magnetic stirrer, 20 g of a low-viscosity liquid maleimide resin (manufactured by DMI, maleimide-terminated polyimide resin, trade name: BMI-689, 1000 to 2000 mPa·s (25°C)) was added. Then, the eggplant-shaped flask containing the mixed solution of the MEK dispersion of the obtained surface-modified silica particles and the maleimide resin was set in a rotary evaporator, and distillation was performed under reduced pressure at a bath temperature of 80°C and 400 to 30 Torr to replace the dispersion medium from MEK to the maleimide resin, thereby obtaining a maleimide resin dispersion of the surface-modified silica particles. The obtained maleimide resin dispersion of the surface-modified silica particles had a silica concentration of 30.4% by mass, a water content of 0.1% by mass or less, a methanol content of 0.1% by mass or less, a MEK content of 0.1% by mass or less, a viscosity of 6000 - 7000 mPa·s (B-type viscometer, temperature 25°C), an average dispersed particle diameter of 79 nm by the DLS method, and had a yellow transparent appearance. Furthermore, the obtained maleimide resin dispersion of the surface-modified silica particles showed no change in appearance and no precipitated sediment even after standing at room temperature for one week. Furthermore, the obtained maleimide resin dispersion of the surface-modified silica particles was applied onto a glass substrate degreased with acetone using a manual bar coater (gap: 25 μm), and baked on a hot plate heated to 100°C for 30 minutes under a nitrogen atmosphere. Then, after raising the temperature of the hot plate to 230°C, it was baked for 120 minutes to obtain a cured film of the composite material containing the surface-modified silica particles and the maleimide resin (see Fig. 3(B)). The obtained cured film was yellow transparent and no peeling from the glass substrate was observed (in Fig. 1, the periphery of the part coated with the resin dispersion and the low-viscosity liquid maleimide resin described later is shown with a black frame for reference). The film thickness was measured with a constant-pressure thickness measuring instrument (manufactured by Techlock Co., Ltd., model: PG-01A) and was 19 μm. On the other hand, as an example without using the surface-modified silica particles, only the above-mentioned low-viscosity liquid maleimide resin (trade name: BMI-689) was used. This was applied onto a glass substrate degreased with acetone using a manual bar coater (gap: 25 μm), and baked on a hot plate heated to 100°C for 30 minutes under a nitrogen atmosphere. Then, after raising the temperature of the hot plate to 230°C, it was baked for 120 minutes to obtain a cured film of only the maleimide resin (see Fig. 3(A)). The obtained cured film was yellow transparent, but peeling from the glass substrate was observed.

[0289] (Evaluation of the polyimide resin composition - Part 1) Example 7-1: The silica dry powder obtained in Examples 1-3 was redispersed in DMAC so that the silica concentration became 30% by mass. The obtained DMAC redispersed sol was added and mixed in a glass bottle to the polyamic acid obtained in Synthesis Example 30 so that the resin / SiO2 mass ratio became 80 / 20. Next, by defoaming and stirring with a vacuum defoamer (manufactured by EME, product name V-mini300) for 20 minutes, a silica-containing polyamic acid was obtained. Next, the obtained silica-containing polyamic acid was applied onto a Cu plate (manufactured by AS ONE Corporation, product name HC0536, 300 mm × 300 mm, 0.5 mm thick) with an applicator (manufactured by BEVS, product name: Film Applicator B / M150mm with film thickness adjustment function), and then solvent removal and heat curing were carried out under the conditions of 70°C for 30 minutes, 100°C for 30 minutes, 150°C for 30 minutes, and 290°C for 60 minutes to bake the silica-containing polyimide on the Cu plate (film thickness: 29 - 32 μm). This was cut into 5 cm squares and used as a sample for insulation testing.

[0290] (Measurement of insulation breakdown life) A plate-shaped sample with a size of 50 mm × 50 mm and a thickness of 0.5 mm was used to measure the insulation breakdown life at a test temperature of 155°C (in air), an applied voltage of 2.0 kV, and a frequency of 50 Hz using an insulation breakdown test device manufactured by Yamayo Test Instruments Co., Ltd., model: YST-243WS. The electrode shape was a flat plate electrode (φ = 25 mm) at the bottom and a spherical electrode (φ = 20 mm) at the top, and both electrodes were installed in contact with the sample for testing. Measurements were made 3 - 4 times at an applied voltage of 2.0 kV and the average value was measured. The insulation life of the sample formulated with Examples 1-3 was 196 minutes. In addition, only the polyimide resin without silica was used as a blank sample and measured in the same manner. The insulation life of the sample of only the polyimide resin was 21 minutes.

[0291] (Evaluation of polyimide resin composition part 2) Example 7-2: 10 g of P3 obtained in Synthesis Example 31 was dissolved in DMAC at 10% by mass to obtain the target polyimide solution (PI-A). Next, 10 g of the dry powder obtained in Examples 1-23 was redispersed in DMAC at 40% by mass to obtain a redispersion. Further, PI-A was added to this redispersion so that the weight ratio of polyimide to dry powder was 1:1, and it was stirred at 1500 rpm for 10 minutes using a vacuum degassing machine (manufactured by EME, product name V-mini300) to obtain the target polyimide / silica dispersion. This polyimide / silica dispersion was applied onto Eagle XG with a bar coater to a thickness of 25 μm. Further, it was baked at 90 °C for 1 hour and 230 °C for 1 hour under a nitrogen atmosphere to obtain a polyimide silica coating film. The obtained film showed self-supporting properties.

[0292] (Silica sol dispersed in an epoxy monomer) Example 8-1: Regarding the surface-modified silica particles obtained in Synthesis Example 3, the compatibility between the surface-modified silica particles and an organic resin material (epoxy resin) was confirmed. 50 g of the MEK dispersion of the surface-modified silica particles obtained in Synthesis Example 3 was charged into a 300 mL eggplant-shaped flask, and while stirring with a magnetic stirrer 20 g of an epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., bisphenol A type epoxy resin, product name: YD-8125, 3900~5300 mPa·s) was added. Then, the eggplant-shaped flask containing the mixed solution of the MEK dispersion of the obtained surface-modified silica particles and the epoxy resin was set on a rotary evaporator, and distillation was carried out under reduced pressure at a bath temperature of 80 °C and 400~30 Torr to replace the dispersion medium from MEK to the epoxy resin, thereby obtaining an epoxy resin dispersion of the surface-modified silica particles. The obtained epoxy resin dispersion of the surface-modified silica particles had a silica concentration of 32.1% by mass, a water content of 0.1% by mass or less, a MeOH content of 0.1% by mass or less, a MEK content of 0.1% by mass or less, a viscosity of 14000~16000 mPa·s (B-type viscometer, temperature 25 °C), an average dispersed particle diameter of 79 nm by the DLS method, and an epoxy equivalent of 264 g / eq (in accordance with JIS K7236), and the appearance was white and transparent. Furthermore, the obtained epoxy resin dispersion of the surface-modified silica particles showed no change in appearance and no precipitation sediment even after standing at room temperature for one week.

[0293] (Sedimentation recovery of surface-modified silica particles) Example 9-1: 50 g of the MeOH dispersion (32) of the surface-modified intermediate silica particles obtained in Synthesis Example 32 was placed in a 200 ml beaker, and 50 g of pure water was added. After standing for 30 minutes, the surface-modified intermediate silica particles settled, so the supernatant was removed by decantation to recover the water-containing surface-modified intermediate silica particles. The beaker containing the obtained water-containing surface-modified intermediate silica particles was placed in a vacuum dryer (temperature: 60 to 100 °C, pressure: -0.1 MPa in gauge pressure of the Bourdon tube vacuum gauge scale; in terms of absolute pressure (atmospheric pressure + gauge pressure), 0.1013 MPa - 0.1 MPa = 1.3 kPa), and held until the moisture content of the water-containing surface-modified intermediate silica particles became 1.0 mass% or less per silica particle. Next, 5.0 g of the obtained surface-modified intermediate silica particles with reduced moisture was charged into a 50 ml glass vial, and 18.5 g of MeOH was added. Then, by stirring for 2 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5), a redispersed MeOH dispersion of the surface-modified intermediate silica particles redispersed in MeOH was obtained. The obtained redispersed MeOH dispersion of intermediate silica sol using MeOH as the redispersing medium had an average particle diameter of 21 nm by the DLS method, a pH of 7.4, a silica concentration of 21.1 mass%, and a viscosity of 2.1 mPa·s. In addition, there was no clogging during filtration using a nylon syringe filter (product name, pore diameter 0.45 μm, manufactured by Membrane Solutions), indicating good dispersibility.

[0294] (Evaluation of fluidity of redispersed sol of metal oxide powder) Example 10-1: A 50-ml eggplant-shaped flask containing 10 g of the sol obtained in Synthesis Example 32 was set on a rotary evaporator, and the dispersion solvent was removed under reduced pressure at a bath temperature of 80°C and 50 Torr to obtain a dried product of the sol. Further, the obtained dried product was crushed with a mortar and pestle to obtain a powder of silica particles. Thereafter, 1.4 g of the obtained silica particle powder was charged into a 13-ml glass vial so as to have the combination and concentration with the redispersion medium described in Tables 15 and 16, and mixed. The mixing was stirred for 12 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). When the obtained redispersed sol had fluidity, it was considered redispersible; if it did not have fluidity, it was considered non-redispersible. Further, the viscosity of the redispersed sol that was further redispersible was measured using an EMS viscometer. In Tables 15 and 16, when it was redispersible, "OK" was described; when it was non-redispersible, "NG" was described; and when not implemented, "-" was described as the result. Further, from the DLS measurement results after redispersion, the viscosity ratio of the redispersed sol to the dispersion medium: (viscosity of the redispersed sol) / (viscosity of the dispersion medium) was described.

[0295] Examples 10-2 to 10-15, Comparative Examples 10-1 and 10-2: In the same manner as in Example 10-1, redispersed sols were prepared so as to have the metal oxide particles, redispersion medium, and concentration described in Tables 15 and 16. The obtained results are described in Tables 15 and 16.

[0296] [Table 15]

[0297] [Table 16]

[0298] (Evaluation of the fluidity of a mixed sol of two particles with different average primary particle diameters) Example 11-1: 0.1 g of a PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 12 nm obtained in Example 10-5 (solid content: 30% by mass, EMS viscosity: 3 mPa·s) and 0.9 g of a PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 71 nm obtained in Example 10-13 (solid content: 30% by mass, EMS viscosity: 1650 mPa·s) were charged into a 13-ml glass vial and stirred for 2 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). The obtained two-particle mixed PGMEA sol with different average primary particle diameters contains metal oxide particles with a solid content of 30% by mass, an EMS viscosity of 449 mPa·s, a viscosity ratio (sol / dispersion medium) of 397, and average primary particle diameters of 12 nm and 71 nm. The largest peak a in the range of D50 to D90 exists in the range of 35 nm or more and 200 nm or less, and the largest peak b in the range of D10 to D50 exists in the range of 5 nm or more and less than 100 nm. The ratio of (volume of metal oxide particles with an average primary particle diameter of 71 nm) / (volume of metal oxide particles with an average primary particle diameter of 12 nm) is 21. The sol has a lower viscosity by more than half compared to the PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 71 nm obtained in Example 10-13, and the fluidity is improved.

[0299] Example 11-2: 0.1 g of a PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 12 nm obtained in Example 10-5 (solid content: 60% by mass, EMS viscosity: 51 mPa·s) and 0.9 g of a PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 80 nm obtained in Example 10-14 (solid content: 60% by mass, EMS viscosity: 3150 mPa·s) were charged into a 13-ml glass vial and stirred for 2 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-RO TAR MR-5). The two-particle mixed PGMEA sols with different obtained average primary particle sizes have a solid content of 60% by mass, a volume ratio of metal oxide particles (80 nm metal oxide particles / 12 nm metal oxide particles) of 9, an EMS viscosity of 7 mPa·s, a viscosity ratio (sol / dispersion medium) of 6, contain metal oxide particles with average primary particle sizes of 12 nm and 80 nm, the largest peak a in the range of D50 to D90 exists in the range of 35 nm or more and 200 nm or less, the largest peak b in the range of D10 to D50 exists in the range of 5 nm or more and less than 100 nm, and compared with the PGMEA dispersion sol of the metal oxide particles with an average primary particle size of 80 nm obtained in Example 10-14, the viscosity is reduced by more than half, and the fluidity is improved.

[0300] Example 11-3: 0.18 g of the dry powder of metal oxide particles with an average primary particle size of 12 nm obtained in Example 10-5, 1.62 g of the dry powder of metal oxide particles with an average primary particle size of 80 nm obtained in Example 10-14, and 1.2 g of PGMEA were charged into a 13 ml glass vial and stirred for 12 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). The two-particle mixed PGMEA sols with different obtained average primary particle sizes have a solid content of 60% by mass, a volume ratio of metal oxide particles (80 nm metal oxide particles / 12 nm metal oxide particles) of 9, an EMS viscosity of 7 mPa·s, a viscosity ratio (sol / dispersion medium) of 6, contain metal oxide particles with average primary particle sizes of 12 nm and 80 nm, the largest peak a in the range of D50 to D90 exists in the range of 35 nm or more and 200 nm or less, the largest peak b in the range of D10 to D50 exists in the range of 5 nm or more and less than 100 nm, and compared with the PGMEA dispersion sol of the metal oxide particles with an average primary particle size of 80 nm obtained in Example 10-14, the viscosity is reduced by more than half, and the fluidity is improved.

[0301] Example 11-4: 0.1 g of a PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 43 nm obtained in Example 10-12 (solid content: 30% by mass, EMS viscosity: 5 mPa·s) and 0.9 g of a PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 71 nm obtained in Example 10-15 (solid content: 30% by mass, EMS viscosity: 27 mPa·s) were charged into a 13-ml glass vial and stirred for 2 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). The obtained two-particle mixed PGMEA sol with different average primary particle diameters contains metal oxide particles with a solid content of 30% by mass, an EMS viscosity of 16 mPa·s, a viscosity ratio (sol / dispersion medium) of 14, and average primary particle diameters of 43 nm and 71 nm. The largest peak a in the D50 - D90 range exists in the range of 35 nm or more and 200 nm or less, and the largest peak b in the D10 - D50 range exists in the range of 5 nm or more and less than 100 nm. The ratio of (volume of metal oxide particles with an average primary particle diameter of 71 nm) / (volume of metal oxide particles with an average primary particle diameter of 43 nm) is 13. Compared with the PGMEA dispersion sol of metal oxide particles with an average primary particle diameter of 71 nm obtained in Example 10-15, the viscosity was reduced by 10 mPa·s or more, and the fluidity was improved.

Industrial Applicability

[0302] Provided are metal oxide particles that can be concentrated at a high concentration in an organic solvent that is a dispersion medium of a metal oxide sol and can be redispersed in the organic solvent, a metal oxide sol containing the metal oxide particles, and methods for producing the same.

Claims

1. Metal oxide particles having a surface-coated with a hydrolysate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2) and a hydrolysate of a silane compound (B) having three chemical groups (b1) and one hydrolyzable group (b2), The silane compound (A) is represented by the following formula (1): 【Chemistry 1】 (In formula (1), R １ is a chemical group (a1) which is at least one chemical group selected from the group consisting of linear or cyclic alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 40 carbon atoms, and (meth)acryloxy group-containing alkyl groups and is bonded to a silicon atom via a Si-C bond; R ２ and each of (a2) is a hydrolyzable group, each of which is at least one hydrolyzable group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 2 to 10 carbon atoms, and a halogen group; The silane compound (B) is represented by the following formula (2) and the following formula (3): 【Chemistry 2】 (In formula (2) and formula (3), R ３ and R ４ is a chemical group (b1) which is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms and which is bonded to a silicon atom by a Si—C bond; R ５ and Y is a hydrolyzable group (b2) each representing an alkoxy group, an acyloxy group, or a halogen atom, and Y represents an NH group or an oxygen atom; The metal oxide particles contain a basic compound (I), and the metal oxide particles have a particle refractive index of 1.4 to 3.0 and are dispersible in an organic solvent at a metal oxide concentration of 40 mass% or more, or the metal oxide particles have a particle refractive index of 1.1 to less than 1.4 and are dispersible in an organic solvent at a metal oxide concentration of 25 mass% or more.

2. 2. The metal oxide particles according to claim 1, wherein the metal oxide particles have an average primary particle size of 5 to 120 nm, and the metal component is selected from the group consisting of oxides of at least one metal component selected from silicon, metal elements in the fourth period of the periodic table, and metal elements in the fifth period of the periodic table.

3. 2. The metal oxide particles according to claim 1, wherein the metal oxide particles have an average primary particle size of 5 to 120 nm, and the metal component is an oxide of at least one metal component selected from the group consisting of silicon, titanium, tin, cobalt, nickel, zirconium, antimony, cerium, magnesium, calcium, strontium, iron, and aluminum.

4. On the surface of the metal oxide particles, a silane compound (C) represented by the following formula (4): 【Chemistry 3】 (In formula (4), R ６ is a chemical group (c1) which is at least one chemical group selected from the group consisting of linear or cyclic alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 40 carbon atoms, and (meth)acryloxy group-containing alkyl groups and is bonded to a silicon atom by a Si-C bond; R ７ and each of the hydrolyzable groups (c1) is at least one hydrolyzable group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an acyloxy group having 2 to 10 carbon atoms, and a halogen group.

5. Silane compounds on the surface of metal oxide particles ２９ The metal oxide particles according to claim 1, wherein, in a Si-NMR measurement, the content ratios of the M structure, the D structure, and the T structure are such that, when the total content of the M structure, the D structure, and the T structure is taken as 100 mol %, the M structure is 30 mol % or more and less than 60 mol %, the D structure is 30 mol % or more and less than 90 mol %, and the T structure is 0 mol % or more and less than 30 mol %.

6. 2. The metal oxide particles according to claim 1, wherein the degree of hydrophobicity according to a methanol titration method is 20 to 80% by volume.

7. 2. The metal oxide particles according to claim 1, wherein the degree of hydrophobicity as determined by methanol titration is from 20% by volume to less than 60% by volume.

8. Measurement by the leaching method revealed that Al was present on the surface of metal oxide particles. ２ O ３ 2. The metal oxide particles according to claim 1, in which aluminum atoms are bonded at a ratio (A) of 20 to 20,000 ppm / gram of metal oxide in terms of aluminum atoms per gram of metal oxide.

9. The leaching method is a method for leaching metal oxide particles with an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, and the compound containing aluminum atoms bonded to the surface of the metal oxide particles is called Al ２ O ３ The metal oxide particles according to claim 8, wherein the ratio (A) of the metal oxide particles to 1 g of metal oxide is calculated in terms of the amount of the metal oxide particles.

10. Measurements using a dissolution method using a hydrofluoric acid solution showed that the aluminum atoms present throughout the metal oxide particles were Al ２ O ３ The metal oxide particles according to claim 8, wherein the metal oxide particles are bonded at a ratio (B) of 50 to 50,000 ppm / g of metal oxide in terms of metal oxide equivalent, and the value obtained by dividing the ratio (A) by the ratio (B) is 0.001 to 1.

0.

11. 2. The metal oxide particles according to claim 1, wherein the basic compound (I) is an amine, an alkali metal hydroxide, an alkali metal alkoxide compound, or a quaternary ammonium hydroxide.

12. 2. The metal oxide particles according to claim 1, which are solid metal oxide particles having no space inside the particles, hollow metal oxide particles having space inside the outer shell, or mixed metal oxide particles of these particles.

13. A metal oxide sol obtained by dispersing the metal oxide particles according to any one of claims 1 to 12 in an organic solvent and / or a reactive monomer.

14. The average particle size of the metal oxide particles in the metal oxide sol as measured by dynamic light scattering is 5 to 240 nm. The metal oxide sol according to claim 13.

15. 14. The metal oxide sol according to claim 13, wherein the organic solvent is an alcohol, a ketone, an ether, an ester, an amide, a glycol, or a hydrocarbon.

16. 14. The metal oxide sol according to claim 13, wherein the reactive monomer is an acrylic compound, an allyl compound, an isocyanate compound, an isothiocyanate compound, an epoxy compound, a diamine-containing compound, a diol-containing compound, a dicarboxylic acid-containing compound, a disulfonyl chloride-containing compound, a dithiol-containing compound, a disulfide-containing compound, a divinyl-containing compound, a diallyl-containing compound, styrene, a tetracarboxylic acid anhydride, a bismaleimide, a vinyl-containing compound, a lactone ring-containing compound, a lactide-containing compound, a fluorine-containing compound, a cyclic olefin-containing compound, ethylene, propylene, or a silane.

17. The metal oxide sol according to claim 13 is dried under drying conditions of 60° C. to 100° C. and 50 Torr, and then redispersed in an organic solvent. The metal oxide sol has an average particle size (nm) of metal oxide particles in the metal oxide sol as measured by dynamic light scattering in a dispersion solvent, the ratio of (average particle size after redispersion as measured by dynamic light scattering) / (average particle size before redispersion as measured by dynamic light scattering) being 0.6 to 3.

0.

18. The metal oxide sol according to claim 13, wherein after storage at 50° C. for 4 weeks, the average particle size (nm) of metal oxide particles in the metal oxide sol as measured by dynamic light scattering in the metal oxide sol has a ratio of (average particle size as measured by dynamic light scattering after storage at 50° C.) / (average particle size as measured by dynamic light scattering before storage at 50° C.) of 0.8 to 2.

0.

19. The metal oxide particles have a refractive index of 1.4 to 3.0, and the metal oxide particles are redispersed in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20° C. to a metal oxide concentration of 60 mass %, and the EMS viscosity (mPa·s) of the metal oxide sol obtained by redispersing the metal oxide particles in the dispersion medium is 1 to 3,000, where the ratio of (EMS viscosity of the redispersed metal oxide sol) / (EMS viscosity of the dispersion medium) is 1 to 3,000, and the dispersion medium is an organic solvent or a reactive monomer.

20. The metal oxide particles have a refractive index of 1.1 to 1.4, and the metal oxide particles are redispersed in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20° C. to a metal oxide concentration of 30 mass %, and the EMS viscosity (mPa·s) of the metal oxide sol obtained by redispersing the metal oxide particles in the dispersion medium has a ratio of (EMS viscosity of the redispersed metal oxide sol) / (EMS viscosity of the dispersion medium) of 1 to 3,000.

21. A metal oxide sol comprising the metal oxide particles according to claim 19 or 20 and a dispersion medium, wherein the metal oxide particles comprise metal oxide particles A having an average primary particle diameter of 35 to 200 nm and metal oxide particles B having an average primary particle diameter of 5 to 100 nm, a ratio of (average primary particle diameter of metal oxide particles A) / (average primary particle diameter of metal oxide particles B) is 1.1 to less than 20, and a ratio of (EMS viscosity of metal oxide sol) / (EMS viscosity of dispersion medium) is 1 to 1,000.

22. A dispersion varnish composition comprising the metal oxide particles according to any one of claims 1 to 12 and an organic component.

23. The organic component is an acrylic compound, an allyl compound, an isocyanate compound, an isothiocyanate compound, an epoxy compound, a diamine-containing compound, a diol-containing compound, a dicarboxylic acid-containing compound, a disulfonyl chloride-containing compound, a dithiol-containing compound, a disulfide-containing compound, a divinyl-containing compound, a diallyl-containing compound, a styrene, a tetracarboxylic acid anhydride, a bismaleimide, a vinyl-containing compound, a lactone ring-containing compound, a lactide-containing compound, 23. The dispersion varnish composition of claim 22, comprising at least one monomer selected from a fluorine-containing compound, a cyclic olefin-containing compound, ethylene, propylene, or a silane, or a polymer containing these components.

24. A composite composition comprising the metal oxide particles according to any one of claims 1 to 12 and an organic resin material or a polysiloxane resin.

25. 25. The composite composition according to claim 24, wherein the organic resin material is at least one selected from the group consisting of styrene-based resins, epoxy-based resins, thioepoxy resins, novolac-based resins, cyanate-based resins, phenol-based resins, acrylic-based resins, maleimide-based resins, polyester-based resins, urethane-based resins, polyurea resins, polyimide-based resins, polyamide-based resins, polyamic acid resins, polyhydroxyimide resins, polybenzoxazole resins, polybenzimidazole resins, polybenzothiazole resins, polyhydroxyamide resins, polyhydroxyazomethine resins, polyether-based resins, polybenzoxazine resins, polytetrafluoroethylene-based resins, cycloolefin polymer-based resins, unsaturated polyester-based resins, vinyl triazine-based resins, polyphenylene sulfide-based resins, crosslinkable polyphenylene oxide-based resins, curable polyphenylene ether-based resins, and condensation-based resins.

26. The dispersion varnish composition is a semiconductor device material, a semiconductor element material, a semiconductor resist material, a nanoimprint, an insulating film material, a copper-clad laminate material, a printed circuit board material, a printing plate material, a printing ink material, a pigment, a paint, a sealant material, a hard coat material, a 3D print material, an anti-reflective film material, a structural color forming member, a material for in-vehicle parts, a material for electronic parts, a machine element part, an adhesive material, a battery material, a power generation material, a charge imparting material, a conductivity imparting material, a powder fluidity imparting material, a cosmetic material, a flexible wiring material, a liquid crystal display material, an organic EL display material, a micro LED display material, a QD-EL display material, a flexible display material, an antenna material, an optical wiring material, or a sensing material. The dispersion varnish composition according to claim 22 is used.

27. The composite composition is a semiconductor device material, a semiconductor element material, a semiconductor resist material, a nanoimprint, an insulating film material, a copper-clad laminate material, a printed circuit board material, a printing plate material, a printing ink material, a pigment, a paint, a sealant material, a hard coat material, a 3D print material, an anti-reflective film material, a structural color forming member, a material for in-vehicle parts, a material for electronic parts, a machine element part, a material for adhesives, a material for batteries, a material for power generation, a material for imparting electrostatic charge, a material for imparting electrical conductivity, a material for imparting powder fluidity, a material for cosmetics, a flexible wiring material, a material for liquid crystal displays, a material for organic EL displays, a material for micro LED displays, a material for QD-EL displays, a flexible display material, an antenna material, an optical wiring material, or a sensing material. The composite composition according to claim 24, which is used for the composite composition.

28. The following steps (A) to (C): Step (A): preparing a metal oxide sol in which metal oxide particles having an average primary particle size of 5 to 120 nm are dispersed in an alcohol having 1 to 5 carbon atoms; Step (B): adding a silane compound (A) represented by formula (1) defined in claim 1, a silane compound (B) selected from the group consisting of formulas (2) and (3) defined in claim 1, and a basic compound (I) to the metal oxide sol obtained in step (A); The method for producing metal oxide particles according to any one of claims 1 to 12, further comprising: step (C): drying the metal oxide sol obtained in step (B).

29. Among the steps (A) to (C) according to claim 27, the step (C) is the following step (C'), or the steps (A) to (C) further include the following step (D): Step (C'): a step of subjecting the metal oxide sol obtained in step (B) to solvent replacement with an organic solvent other than an alcohol having 1 to 5 carbon atoms; The method for producing a metal oxide sol according to claim 13, further comprising: (D) a step of dispersing the metal oxide particles obtained in (C) in an organic solvent.

30. The following steps (E) to (G): Step (E): adding water to a dispersion of metal oxide particles dispersed in an organic solvent; Step (F): after step (E), removing the supernatant solvent to obtain a precipitate; 2. The method for producing metal oxide particles according to claim 1, further comprising: (G) drying the precipitate obtained after (F) to obtain a powder of metal oxide particles.

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