Metal oxide particles having improved hydrophobicity, highly concentrated metal oxide sol, and methods for producing same

Abstract

[Problem] To provide: metal oxide particles that can be highly concentrated in an organic solvent, which is a dispersion medium for a metal oxide sol, and can also be redispersed in the organic solvent; a metal oxide sol containing the metal oxide particles; and a method for producing same. [Solution] Metal oxide particles surface-coated with a hydrolysate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2), wherein the metal oxide particles contain a basic compound (I) (excluding ammonia), have a hydrophobicity of 30-80 vol% as measured by a methanol titration method, and can be dispersed at a particle refractive index of 1.4-3.0 and at a metal oxide concentration of at least 40 mass% in an organic solvent, or can be dispersed at a particle refractive index of at least 1.1 and less than 1.4 and at a metal oxide concentration of at least 25 mass% in an organic solvent.

Description

Metal oxide particles with improved hydrophobicity, highly concentrated metal oxide sol, and methods for producing the same

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

[0002] Colloidal metal oxide particle dispersions (sols), such as silica sols, are liquids in which silica particles are dispersed in a liquid medium. However, silica particles (silica powder) can be obtained by removing the liquid dispersion medium. When these metal oxide particles are used as particulate metal oxide powders, their volume fraction is significantly lower than when they are used as metal oxide sols, reducing transportation costs. Furthermore, when metal oxide particles are used as additives in applications where the metal oxide is used, there is no need to remove the dispersion medium after addition, which offers advantages in terms of process control.

[0003] For coatings containing metal oxide particles as an added component, attempts have been made to utilize the properties of metal oxides to improve abrasion resistance, refractive index adjustment, heat resistance, heat insulation, electrical insulation, dielectric properties, etc.

[0004] In the manufacturing process of a coating that contains metal oxides as additive components and is formed on a substrate together with organic components, the organic components can often be removed using chemical etching or gas etching, but metal oxide particles are highly resistant to etching and are difficult to remove.

[0005] Redispersible nanoparticles have been disclosed that are obtained by adding a surface modifier containing a functional group selected from thiol, sulfide, disulfite, or polysulfide to a nanoparticle dispersion and then radically polymerizing the surface modifier together with an organic monomer (see Patent Document 1).

[0006] Patent Document 2 discloses a method for producing surface-modified silica particles having an average particle size of 100 nm or less, comprising the steps of: a) providing a pre-dispersion; b) high-pressure pulverization of the pre-dispersion to form a dispersion; and c) removing the liquid phase of the dispersion, and the method also discloses redispersible, surface-modified silicon dioxide particles coated with a silylamine, which are used in toner powders, silicone rubbers, adhesives, and scratch-resistant surface coatings.

[0007] Special table 2009-532514 publication Special table 2011-528310 publication

[0008] The present invention addresses the problem of providing metal oxide particles that can be concentrated to a high concentration in an organic solvent, which is a dispersion medium for a metal oxide sol, and that can be redispersed in the organic solvent; a metal oxide sol containing the metal oxide particles; and methods for producing the same.

[0009] In a first aspect, the present invention provides metal oxide particles surface-coated with a hydrolyzate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2), the metal oxide particles comprising a basic compound (I) and having a hydrophobicity of 30 to 80% by volume as measured by a methanol titration method, the metal oxide particles having a particle refractive index of 1.4 to 3.0 and being dispersible in an organic solvent at a metal oxide concentration of 40% by mass or more, or the metal oxide particles having a particle refractive index of 1.1 to less than 1.4 and being dispersible in an organic solvent at a metal oxide concentration of 25% by mass or more; in a second aspect, the metal oxide particles according to the first aspect, the metal oxide particles having an average primary particle size of 5 to 120 nm, and the metal component being selected from the group consisting of silicon, metal elements of the fourth period of the periodic table, and metal elements of the fifth period of the periodic table; According to a third aspect, the metal oxide particles according to the first aspect, in which the metal oxide particles have an average primary particle diameter of 5 to 120 nm and the metal component is 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; and according to a fourth aspect, the silane compound (A) is represented by the following formula (1):

[0010]

[0011] (In formula (1), R １ are chemical groups (a1) each of 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 which are bonded to a silicon atom by a Si—C bond; R ２ and each of the hydrolyzable groups (a2) 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.

[0012]

[0013] (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 the silicon atom by a Si—C bond, and R ５ and Y are hydrolyzable groups (b2), each of which is R ５ represents an alkoxy group, an acyloxy group, or a halogen atom, and Y represents an NH group or an oxygen atom. As a sixth aspect, the present invention provides metal oxide particles according to any one of the first to fourth aspects, which are surface-coated with a hydrolyzate of at least one silane compound selected from the group of silane compounds represented by the following formula (4):

[0014]

[0015] (In formula (4), R ６are chemical groups (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 an alkyl group containing a (meth)acryloxy group, and which is bonded to a silicon atom by a Si—C bond; R ７ and (c2) are hydrolyzable groups 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 atom. ２９the metal oxide particles according to any one of the first to sixth aspects, in which, in Si-NMR measurement, the content ratios of the M structures, the D structures, and the T structures, when the total of the M structures, the D structures, and the T structures is taken as 100 mol%, are such that the M structures account for 30 mol% or more and less than 60 mol%, the D structures for 30 mol% or more and less than 90 mol%, and the T structures for 0 mol% or more and less than 30 mol%; as an eighth aspect, the metal oxide particles according to any one of the first to seventh aspects, in which the basic compound (I) is an amine, an alkali metal hydroxide, an alkali metal alkoxide compound, or a quaternary ammonium hydroxide; as a ninth aspect, the metal oxide particles according to any one of the first to eighth aspects, in which 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; According to a tenth aspect, there is provided a metal oxide sol in which the metal oxide particles according to any one of the first to ninth aspects are dispersed in an organic solvent and / or a reactive monomer; according to an eleventh aspect, there is provided a metal oxide sol according to the tenth aspect, in which the metal oxide particles in the metal oxide sol have an average particle size measured by a dynamic light scattering method of 5 to 200 nm; according to a twelfth aspect, there is provided a metal oxide sol according to the tenth or eleventh aspect, in which the organic solvent is an alcohol, a ketone, an ether, an ester, an amide, a glycol, or a hydrocarbon; As a thirteenth aspect, the metal oxide sol according to any one of the tenth to twelfth aspects, in which 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;According to a fourteenth aspect, the metal oxide sol according to any one of the tenth to thirteenth aspects is dried under drying conditions of 60° C. to 100° C. and 50 Torr, and then redispersed in an organic solvent, wherein the ratio of the average particle size (nm) of the metal oxide particles measured by dynamic light scattering in the dispersion solvent, (average particle size measured by dynamic light scattering after redispersion) / (average particle size measured by dynamic light scattering before redispersion) is 0.6 to 3.0; and according to a fifteenth aspect, the metal oxide sol according to any one of the tenth to fourteenth aspects is stored at 50° C. for four weeks, wherein the ratio of the average particle size (nm) of the metal oxide particles measured by dynamic light scattering in the metal oxide sol, (average particle size measured by dynamic light scattering after storage at 50° C.) / (average particle size measured by dynamic light scattering before storage at 50° C.) is 0.8 to 2.0. According to a sixteenth aspect, the metal oxide particles have a refractive index of 1.4 to 3.0, and are obtained by redispersing the metal oxide particles in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20°C to a metal oxide concentration of 60%. The EMS viscosity (mPa·s) of the resulting metal oxide sol is 1 to 3000, where the ratio of (the EMS viscosity of the redispersed metal oxide sol) / (the EMS viscosity of the dispersion medium) is 1 to 3000, and the dispersion medium is an organic solvent or a reactive monomer. According to a seventeenth aspect, the metal oxide particles have a refractive index of 1.1 to 1.4, and are obtained by redispersing the metal oxide particles in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20°C to a metal oxide concentration of 30%. The ratio of (the EMS viscosity of the redispersed metal oxide sol) / (the EMS viscosity of the dispersion medium) is 1 to 3000, where the ratio of (the EMS viscosity (mPa·s) of the redispersed metal oxide sol) / (the EMS viscosity of the dispersion medium) is 1 to 3000. According to an eighteenth aspect, there is provided a metal oxide sol comprising the metal oxide particles according to the sixteenth or seventeenth aspect 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, wherein 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 1000; according to a nineteenth aspect, there is provided a dispersion varnish composition comprising the metal oxide particles according to any one of the first to ninth aspects and an organic component;as a twentieth aspect, a dispersion varnish composition according to the nineteenth aspect, in which the organic component includes at least one monomer selected from 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, and a silane, or a polymer containing such a component; as a twenty-first aspect, a composite composition including the metal oxide particles according to any one of the first to ninth aspects, and an organic resin material or a polysiloxane-based resin; According to a twenty-second aspect, there is provided a composite composition according to the twenty-first aspect, wherein the organic resin material is at least one selected from the group consisting of a styrene-based resin, an epoxy-based resin, a thioepoxy resin, a novolac-based resin, a cyanate-based resin, a phenol-based resin, an acrylic-based resin, a maleimide-based resin, a polyester-based resin, a urethane-based resin, a polyurea resin, a polyimide-based resin, a polyamide-based resin, a polyamic acid resin, a polyhydroxyimide resin, a polybenzoxazole resin, a polybenzimidazole resin, a polybenzothiazole resin, a polyhydroxyamide resin, a polyhydroxyazomethine resin, a polyether-based resin, a polybenzoxazine resin, a polytetrafluoroethylene-based resin, a cycloolefin polymer-based resin, an unsaturated polyester-based resin, a vinyl triazine-based resin, a polyphenylene sulfide-based resin, a crosslinkable polyphenylene oxide-based resin, a curable polyphenylene ether-based resin, and a condensation-based resin.as a 23rd aspect, the composition according to the 19th or 20th aspect, wherein the dispersion varnish composition is used for a semiconductor device material, a semiconductor element material, a semiconductor resist material, 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-reflection film material, a structural color forming member, a material for an in-vehicle part, a material for an electronic part, a machine element part, an adhesive material, a battery material, a power generation material, a chargeability 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; As a 24th aspect, the composition according to the 21st aspect or the 22nd aspect, wherein the composite composition is used for a semiconductor device material, a semiconductor element material, a semiconductor resist material, 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-reflection film material, a structural color forming member, a material for an in-vehicle part, a material for an electronic part, a machine element part, an adhesive material, a battery material, a power generation material, a chargeability 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; and as a 25th aspect, the composition according to the 21st aspect or the 22nd aspect, wherein the composite composition is used for 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-reflection film material, a structural color forming member, a material for an in-vehicle part, a material for an electronic part, a machine element part, an adhesive material, a battery material, a power generation material, a chargeability 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. a process for producing metal oxide particles according to any one of the fifth to ninth aspects, comprising: step (A): preparing a metal oxide sol in which silica 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) and a silane compound (B) selected from the group consisting of formulas (2) and (3), and a basic compound (I) to the metal oxide sol obtained in step (A); and step (C): drying the metal oxide sol obtained in step (B);According to a 26th aspect, there is provided a method for producing a metal oxide sol according to any one of the 10th to 15th aspects, which includes, in addition to steps (A) to (C) according to the 25th aspect, the following step (D): step (D): dispersing the metal oxide particles obtained in step (C) in an organic solvent; and according to a 27th aspect, there is provided a method for producing metal oxide particles according to any one of the first to ninth aspects, which includes the following steps (E) to (G): step (E): adding water to a dispersion liquid in which the metal oxide particles are dispersed in an organic solvent, step (F): removing the supernatant solvent after step (E) to obtain a precipitate, and step (G): drying the precipitate after step (F) to obtain a metal oxide particle powder.

[0016] Colloidal metal oxide particle dispersions (sols), such as silica sols, are liquids in which silica particles are dispersed in a liquid medium. However, silica particles (silica powder) can be obtained by removing the liquid dispersion medium. When these metal oxide particles are used as particulate metal oxide powders, their volume fraction is significantly lower than when they are used as metal oxide sols, reducing transportation costs. Furthermore, when metal oxide particles are used as additives in applications where the metal oxide is used, there is no need to remove the dispersion medium after addition, which offers advantages in terms of process control.

[0017] In the present invention, powdered metal oxide particles can be redispersed in a wide variety of solvents at high concentrations to redisperse them in the colloidal dispersion state before powderization, which offers significant advantages in terms of transportation costs.In addition, it is possible to use the metal oxide particles in a highly concentrated state before powderization, which offers significant advantages not only in terms of transportation costs but also in terms of reducing the burden of removing the solvent after addition.

[0018] When considered as an additive component, coatings containing metal oxide particles take advantage of the properties of metal oxides to offer advantages such as wear resistance, refractive index adjustment, heat resistance, heat insulation, electrical insulation, and dielectric properties.

[0019] In the case of coatings that contain metal oxides as additive components and are formed on a substrate together with organic components, the manufacturing process includes a subsequent process of removing the entire coating or part of the coating. In such cases, the organic components can often be removed using chemical etching or gas etching, but the metal oxide particles are highly resistant to etching and are difficult to remove.

[0020] When removing these metal oxide particles from a substrate together with a coating, they can be removed using a chemical solution (e.g., chemical removal 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 if only a small amount of chemical solution is used for removal, it is desirable to be able to form a highly concentrated sol. The present invention can provide metal oxide particles that can be removed even with a small amount of chemical solution such as an organic solvent when metal oxide particles contained in a coating are removed with such a chemical solution.

[0021] 3A and 3B are photographs of a film obtained in Example 5-1 and Comparative Example 5-1, respectively. These are photographs of a cured film of only maleimide resin (FIG. 3A, left side of FIG. 3) and a cured film of a composite material containing surface-modified silica particles and maleimide resin (FIG. 3B, right side of FIG. 3). These are photographs of a metal oxide sol in which metal oxide particles were redispersed in a solvent (FIG. 4, left side: Example 1-3, right side: Comparative Example 1-2) in (Evaluation of production of high-concentration sol by redispersion of dried powder).

[0022] The present invention provides 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), the metal oxide particles containing a basic compound (I) and having a hydrophobicity of 30 to 80 vol%, 40 to 80 vol%, 50 to 80 vol%, more than 60 vol% to 80 vol%, 40 to 60 vol%, 30 to less than 60 vol%, or 30 to 50 vol% by methanol titration method, the metal oxide particles having a particle refractive index of 1.4 to 3.0 and a hydrophobicity of SiO in an organic solvent. ２The metal oxide particles are dispersible in an organic solvent at a 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 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% by mass or more, or 30% by mass or more, or 25 to 60% by mass, or 30 to 60% by mass. The metal oxide particles used in the present invention have an average primary particle size of 5 to 120 nm, and the metal component is at least one metal component selected from the group consisting of silicon, metal elements of the fourth period of the periodic table, and metal elements of the fifth period of the periodic table.

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

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

[0025] 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. In particular, silica particles containing silicon as the metal component can be used as the metal oxide particles.

[0026] The metal oxide particles may be single metal oxide particles or composite metal oxide particles, which may be used as a solid solution of metal oxides, composite colloidal particles in which metal oxide particles are chemically bonded at their interfaces, or a mixture of metal oxide particles.

[0027] The metal oxide particles may be solid metal oxide particles with no internal space, hollow metal oxide particles with internal space, or mixtures of these metal oxide particles. The solid metal oxide particles can be described as follows.

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

[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 / nm ２ is.

[0030] The solid metal oxide particles can be obtained as a solid metal oxide sol dispersed in a dispersion medium, and the solid metal oxide sol can have an average particle size of 20 to 250 nm or 20 to 150 nm as measured by dynamic light scattering.

[0031] The solid metal oxide particles can have an EMS viscosity (mPa·s) of a metal oxide sol obtained by redispersing metal oxide particles having a refractive index of 1.4 to 3.0 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, where the ratio of (EMS viscosity of redispersed metal oxide sol) / (EMS viscosity of dispersion medium) is 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 redispersed metal oxide sol) / (EMS viscosity of dispersion medium) of the metal oxide particles to 1 to 3000, the fluidity of the metal oxide sol when redispersed in the dispersion medium is improved.

[0032] The metal oxide particles may be a metal oxide sol containing metal oxide particles and a dispersion medium, and the metal oxide particles may include metal oxide particles A having 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 having an average primary particle diameter of 5 to 100 nm, or 5 nm to 50 nm, or 10 nm to 35 nm, in which the ratio of (average primary particle diameter of metal oxide particles A) / (average primary particle diameter of metal oxide particles A) is 1.1 to less than 20, or 2 to less than 20, or 2 to 10, or 4 to 10, and the ratio of (EMS viscosity of metal oxide sol) / (EMS viscosity of dispersion medium) is 1 to 1,000, or 1 to 100, or 1 to 100, or 1 to 10, or 1.1 to 10. The metal oxide particles contain 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, which creates a bearing effect in which the small particles reduce the coefficient of friction of the large particles, improving the fluidity of the metal oxide particles A in the metal oxide sol and reducing the EMS viscosity of the metal oxide sol.

[0033] The metal oxide particles may have at least two peaks in the average particle size distribution, with the largest peak a in the range of D50 to D90 being 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 being in the range of 5 to 100 nm, or 5 nm to 50 nm, or 10 nm to 35 nm.

[0034] The D10, D50, and D90 are particle sizes that represent the cumulative 10%, 50%, and 90% of the cumulative particle size distribution from the fine particle side. In the present invention, for example, the cumulative particle size distribution value can be measured by particle size distribution using image analysis. In measuring particle size distribution using image analysis, the measurement sample is analyzed as a transmission electron microscope image. Methods for analyzing the D value include the number distribution method and the volume distribution method. The number distribution method captures particles as perfect circles with the same area as the particle itself and measures the percentage of particles having a specific particle size in a certain field of view. In addition, the volume distribution method measures the mass percentage of particles with a specific particle size in a certain amount of sample, assuming that if the particle density is constant, volume and weight are proportional. In the present invention, it is preferable to determine the D values ​​(D10, D50, and D90) using the volume distribution method.

[0035] The metal oxide particles may include metal oxide particles having at least two peaks in a particle size distribution. Here, "at least two peaks," in which the largest peak a in the range of D50 to D90 is present in the range of 35 nm to 200 nm, means that the largest peak in the cumulative particle size distribution is present in the range of D50 to D90, and "at least two peaks," in which the largest peak b in the range of D10 to D50 is present in the range of 5 nm to less than 100 nm, means that the largest peak in the cumulative particle size distribution is present in the range of D10 to D50.

[0036] The metal oxide particles may have a ratio of (volume of metal oxide particles A) / (volume of metal oxide particles B) of 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 (average particle volume calculated from the average primary particle diameter) x (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, and a sol with good fluidity can be obtained.

[0037] The metal oxide particles have 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 solid silica particles with no internal space can be used.

[0038] The metal oxide particles may be 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] Examples of silica particles include colloidal silica particles obtained by a method of heat-treating activated silicic acid obtained by cation-exchanging an aqueous solution of alkali metal silicate, colloidal silica particles obtained by a method of hydrolyzing alkoxide silane 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 produce silica, followed by 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 formed by a combination of a core particle and a shell particle, and examples of core / shell particle combinations include titanium oxide particle / tin oxide and silicon dioxide composite particle, titanium oxide and tin oxide composite particle / tin oxide and silicon dioxide composite particle, titanium oxide particle / zirconium oxide particle / tin oxide and silicon dioxide composite particle, titanium oxide particle / antimony oxide particle, and titanium oxide and tin oxide composite particle / antimony oxide particle. The core-shell type metal oxide particles can be produced by charging the metal oxide of the shell / core metal oxide in a mass ratio of 0.05 to 1.0, 0.1 to 1.0, or 0.15 to 1.0.

[0041] In the present invention, an intermediate layer is present between the core particle and the shell particle, and the intermediate layer is metal oxide particles composed of a combination of at least one 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 component (D), and can be produced by charging (metal oxide other than core) / (metal oxide of core) in a mass ratio of 0.05 to 1.0, or 0.1 to 1.0, or 0.15 to 1.0. The metal oxide particles can be solid metal oxide particles with no internal space, hollow metal oxide particles with internal space in the shell, or a mixture of these particles.

[0042] When a core-shell structure is used, the term "coated with a coating layer containing metal oxide particles having a metal oxide component or metal oxide content different from that of the metal oxide of the core" refers to a case where the metal oxide components of the core and the coating layer are different, or a case where the metal oxide components of the core and the coating partially overlap but the blending ratios of the metal oxides are different. For example, in the case of a tin oxide-silicon dioxide composite oxide (B1) contained in the metal oxide particles of the coating layer, sodium stannate or potassium stannate can be used as the alkali stannate, with sodium stannate being preferred.

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

[0044] The alkali stannate and alkali silicate are prepared as an aqueous solution containing silicon dioxide / stannic oxide in a mass ratio of 0.1 to 5, and the cations present in the aqueous solution are then removed using a cation exchange resin. The alkali stannate and alkali silicate are weighed and dissolved in water so that the mass ratio of silicon dioxide / stannic oxide is 0.1 to 5.0. The preferred solid concentration of the aqueous solution is (SnO ２ +SiO ２ ) is 1 to 12 mass %.

[0045] The prepared aqueous solution is subjected to cation removal using a cation exchange resin. A hydrogen-type strongly acidic cation exchange resin is preferred as the cation exchange resin, and a column packed with Amberlite (trade name) 120B or the like can be used for cation exchange. By carrying out this cation exchange, the silicic acid component and the stannic acid component are polymerized, resulting in the production of silicon dioxide-stannic oxide composite colloidal particles having a primary particle size of 1 to 4 nm. Since these silicon dioxide-stannic oxide composite colloidal particles are poorly stable and will gel within several hours if left standing, an amine compound is added promptly after cation exchange to stabilize the colloidal particles, resulting in a silicon dioxide / stannic oxide mass ratio of 0.1 to 5.0 and an M / (SnO ２ +SiO ２ It is necessary to obtain an aqueous sol of silicon dioxide-stannic oxide composite oxide colloidal particles having a primary particle size of 1 to 4 nm stabilized by an amine compound present in a molar ratio of (SnO ２ +SiO ２ ) is 0.1 to 10 mass %.

[0046] To stabilize the silicon dioxide-stannic oxide composite colloidal particles produced by the cation exchange, M / (SnO ２ +SiO ２ It is appropriate to add the amine compound in an amount such that the molar ratio of M / (SnO) (where M represents an amine compound) is 0.1 to 1.0. ２ +SiO ２ Addition of an amine compound having a molar ratio of silicon dioxide to stannic oxide of less than 0.1 to 1.0 is not preferred because it loses stability and gels after standing for several hours. Next, an aqueous sol of metal oxide colloid particles (A) used for the core having a primary particle size of 5 to 60 nm and an aqueous sol of silicon dioxide to stannic oxide having a mass ratio of silicon dioxide to stannic oxide of 0.1 to 5.0 and an M / (SnO ２ +SiO ２The 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) is mixed with an aqueous sol of silicon dioxide-stannic oxide composite oxide colloid particles (B1) having a primary particle size of 1 to 4 nm and stabilized with an amine compound in a molar ratio of (B1) / (A) (where M represents an amine compound) at a mass ratio of 0.05 to 0.50. The 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 solids concentration of the aqueous sol of the metal oxide colloid particles (A) is 0.5 to 50 mass%, and preferably 5 to 30 mass%.

[0047] The aqueous sol of the metal oxide colloidal particles (A) can have a pH of 5 to 11.5, preferably 7 to 11.5. The pH of the aqueous sol can be adjusted as needed with an alkaline component. Examples of the alkaline component include hydroxides of alkali metals such as lithium, sodium, and potassium; hydroxides of alkaline earth metals such as calcium, magnesium, and strontium; 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 aqueous sol of the metal oxide colloidal particles (A) and the aqueous sol of the coated particles (B1) are preferably mixed under stirring. The mixing ratio of the silicon dioxide-stannic oxide composite oxide colloidal particles (B1) to the metal oxide colloidal particles (A) is preferably 0.05 to 0.50 as a mass ratio (B1) / (A); if the mass ratio is less than 0.05, the metal oxide colloidal particles (A) serving as cores cannot be sufficiently coated with the silicon dioxide-stannic oxide composite oxide colloidal particles (B1), and a stable hydrophilic organic solvent dispersion sol or a hydrophobic organic solvent dispersion sol having a water solubility of 0.05 to 12% by mass cannot be obtained. Furthermore, a mass ratio of 0.50 is sufficient, and if it exceeds 0.50, it is not efficient.

[0048] The sol (A) and the sol (B1) can be mixed at a rate of 22 to 1,000 parts by mass per minute of the solid content of one sol added to the container relative to 100 parts by mass of the solid content of the other sol. The resulting aqueous sol of modified metal oxide colloidal particles (C) is then subjected to cation exchange. A strongly acidic hydrogen-type cation exchange resin is preferably used for the cation exchange. The resulting aqueous sol is then mixed with a cation exchange resin (SnO ) containing an amine compound at a molar ratio of M / (SnO ) to the silicon dioxide-stannic oxide composite oxide colloidal particles (B1). ２ +SiO ２ ) (where M represents an amine compound) is added in an amount such that the ratio M / (SnO ２ +SiO ２ If the molar ratio of M / (SnO) is less than 0.001, the dispersion stability of the hydrophilic organic solvent dispersion sol of the present invention becomes insufficient, which is not preferable. ２ +SiO ２ If the molar ratio of (C) exceeds 0.08, bonding of a silane compound to the particle surface of the modified metal oxide colloidal particles (C) may be hindered.

[0049] Next, the aqueous medium of the obtained aqueous sol is replaced with a hydrophilic organic solvent. Methods for replacing the dispersion medium from water with a hydrophilic organic solvent can be known, such as evaporation replacement under normal or reduced pressure, ultrafiltration membrane method, and solvent extraction method. To efficiently perform the solvent replacement, the obtained aqueous sol is preferably concentrated in advance so that the concentration of the modified metal oxide colloidal particles (C) contained therein is in the range of 1 to 70% by mass, or 10 to 50% by mass. Concentration of the sol can be performed using known methods such as thermal evaporation and ultrafiltration. The temperature of the sol during solvent replacement is in the range from room temperature to the boiling point of the hydrophilic solvent. Solvent replacement is performed until the water content in the sol is less than 5% by mass. The solids concentration of the obtained sol is 20 to 70% by mass, calculated as the total metal oxide concentration of the modified metal oxide colloidal particles (C).

[0050] In the present invention, the dispersion medium for the sol can be an organic solvent such as an alcohol, ketone, ether, ester, amide, glycol, or hydrocarbon. Examples of organic solvents include alcohols, esters, ketones, ethers, amides, esters, or hydrocarbons having 1 to 10 carbon atoms, which may have an ether bond. Examples of alcohols 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, and propylene glycol monopropyl ether. Examples of ketones 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, and cyclohexanone.

[0051] Examples of ethers include linear or cyclic aliphatic ethers having 3 to 30 carbon atoms, such as diethyl ether and tetrahydrofuran. Examples of esters 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, and phenyl propionate. Examples of amides include aliphatic amides having 3 to 30 carbon atoms, such as dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and N-ethylpyrrolidone. Examples of glycols include ethylene glycol, diethylene glycol, propylene glycol, and polyethylene glycol.

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

[0053] In the present invention, amines, alkali metal hydroxides, alkali metal alkoxide compounds, or quaternary ammonium hydroxides can be used as the basic compound (I). Examples of alkali metal hydroxides include hydroxides of lithium, sodium, and potassium. Examples of alkali metal alkoxide compounds include alcoholates of lithium, sodium, and potassium. Examples of amines used in the present invention include secondary amines or tertiary amines having a total of 5 to 35 carbon atoms. These amines can be charged and produced at a pH range of 5 to 11.5, preferably 7 to 11.5. Examples of secondary amines include ethyl n-propylamine, dimethanolamine, diethanolamine, ethylisopropylamine, dipropylamine, diisopropylamine, ethylbutylamine, n-propylbutylamine, dibutylamine, ethylpentylamine, n-propylpentylamine, isopropylpentylamine, dipentylamine, ethyloctylamine, i-propyloctylamine, butyloctylamine, and dioctylamine.

[0054] Examples of the tertiary amine include triethylamine, ethyldi-n-propylamine, diethyl-n-propylamine, tri-n-propylamine, triisopropylamine, ethyldibutylamine, diethylbutylamine, isopropyldibutylamine, diisopropylethylamine, diisopropylbutylamine, tributylamine, ethyldipentylamine, diethylpentylamine, tripentylamine, methyldioctylamine, dimethyloctylamine, ethyldioctylamine, diethyloctylamine, trioctylamine, benzyldibutylamine, diazabicycloundecene, etc. Among the above amines, secondary amines and tertiary amines having an alkyl group having a total of 6 to 35 carbon atoms are preferred, such as diisopropylamine, tripentylamine, triisopropylamine, dimethyloctylamine, trioctylamine, etc. The quaternary ammonium hydroxide is preferably a quaternary ammonium hydroxide having an alkyl group having 1 to 10 carbon atoms, and examples thereof include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetraisopropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0055] The metal oxide particles have Al on the surface thereof as measured by a leaching method. ２ O ３ The aluminum atoms are bonded at a ratio (A) of 100 to 20,000 ppm / metal oxide relative to the mass of the metal oxide.

[0056] The leaching method is a method of 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 ratio (A) of the mass of the metal oxide particles to the mass of the metal oxide is calculated in terms of the mass of the metal oxide particles.

[0057] In the above metal oxide particles, when measured by a dissolution method using an aqueous solution of hydrofluoric acid (hydrofluoric acid), it was found that the aluminum atoms present throughout the metal oxide particles were Al ２ O ３Converted to metal oxide mass of 50 to 50,000, or 120 to 50,000 ppm / SiO ２ and the value obtained by dividing the ratio (A) by the ratio (B) is 0.001 to 1.0.

[0058] In the present invention, hollow metal oxide particles having a space inside the shell include hollow silica particles. Hollow silica particles have a silica shell and a space inside the shell. Hollow silica particles are obtained by forming a shell mainly composed of silica on the surface of a part corresponding to the core, called a template, in a dispersion medium, and then removing the part corresponding to the core.

[0059] In the present invention, the aluminum atoms are converted to Al by measuring the aluminum present on the surface of the metal oxide particles through 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. ２ O ３ For example, when the metal oxide particles are silica particles, the aluminum atoms can be converted into Al 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. ２ O ３ That is, the aluminum atoms measured by the leaching method are present on the surface of the hollow silica particles. ２ O ３ Converted into SiO of hollow silica particles ２ 100 to 20,000 ppm / SiO ２ , or 100 to 15,000 ppm / SiO ２ , 100~10000ppm / SiO ２ , or 200 to 5000 ppm / SiO ２ , or 500 to 5000 ppm / SiO ２ , or 800 to 3000 ppm / SiO ２The presence of aluminosilicate on the surface of silica particles to form aluminosilicate sites is important for dispersion in solvents and resins.

[0060] The aluminum atoms present on the surface of metal oxide particles as aluminosilicate can be leached (eluted) in a structure similar to aluminum salt, aluminum oxide, or aluminum hydroxide by leaching (eluting) the 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 aluminum atoms can be measured from the solution using an ICP emission spectrometer. ２ O ３ In particular, a method of leaching (elution) using an aqueous nitric acid solution is used. The aqueous nitric acid solution used for leaching can have a pH 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.

[0061] For example, when the metal oxide particles are silica particles, aluminum atoms present on the surface of the silica particles as aluminosilicate can be leached (eluted) in a structure similar to aluminum salt, aluminum oxide, or aluminum hydroxide by leaching (eluting) the silica 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 aluminum atoms can be measured from the solution using an ICP emission spectrometer. ２ O ３ The aluminum compound can be expressed in terms of the pH of the silica particle surface. In particular, a method of leaching (elution) using an aqueous nitric acid solution is used. The nitric acid solution used for leaching can be used at a pH 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 kept 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 where the aluminum compound can be eluted by the above-mentioned leaching. This can be determined by evaporating the solvent from the silica sol, further drying the silica gel at 250°C, grinding it to obtain silica powder, adding 20 mL of a nitric acid solution of pH 1.0 to 0.2 g of the silica powder, shaking thoroughly, and then holding it in a thermostatic chamber at 50°C for 17 hours, followed by centrifugal filtration. The aluminum content in the obtained filtrate was measured with an ICP atomic emission spectrometer. ２ O ３ The aluminum content converted into 1000 ppm is divided by the mass of the silica powder to determine the amount of aluminum bound to the silica particle surface (Al ２ O ３ / SiO ２ ) (ppm).

[0063] Furthermore, even when aluminosilicate is formed on the surface of silica particles, depending on the manufacturing method, aluminosilicate may be selectively formed not only on the surface but also inside the silica particles. ２ O ３ Converted into SiO of hollow silica particles ２ The ratio (B) to the mass of SiO is 120 to 50,000 ppm / SiO ２ , or 500 to 20,000 ppm / SiO ２ , or 500 to 10,000 ppm / SiO ２ , or 1000 to 5000 ppm / SiO ２ , or 1000 to 4000 ppm / SiO ２ The ratio of aluminum present on the silica particle surface to the entire silica particle, that is, the ratio (A) / (B), 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. The aluminum atoms present in the entire silica particle can be measured by dissolving the silica particle in a hydrofluoric acid aqueous solution, and the aluminum content can be determined. ２ O ３That is, aluminum atoms present as aluminosilicate throughout the silica particles can be dissolved in a hydrofluoric acid solution and measured from the solution using an ICP emission spectrometer. ２ O ３ can be converted to represent the aluminum atoms present in the entire silica particle.

[0064] In this way, aluminosilicate sites are formed on the surface of the silica particles, and the SiO of the hollow silica particles present on the surface of the silica particles is ２ The amount of negative charge calculated per 1 g of the hollow 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 diameter of 5 to 120 nm, or 10 to 100 nm, a particle refractive index of 1.1 to less than 1.4, an outer shell thickness of 3 to 12 nm, or 5 to 10 nm, and a surface silanol group density of 0.4 to 3.0 / nm. ２ is.

[0065] The hollow silica particles can be obtained as a hollow silica sol dispersed in a dispersion medium, and the hollow silica sol can have an average particle size of 20 to 250 nm or 20 to 150 nm as measured by dynamic light scattering.

[0066] The hollow silica particles can have an 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 at a silica concentration of 30 mass% in a dispersion medium having an EMS viscosity (mPa·s) of 1 to 20 at 20° C., where the ratio of (EMS viscosity of redispersed hollow silica sol) / (EMS viscosity of dispersion medium) is 1 to 3000, 1 to 2500, 1 to 2000, 1 to 1000, 1 to 500, or 1 to 100. By setting the ratio of (EMS viscosity of redispersed hollow silica sol) / (EMS viscosity of dispersion medium) of the hollow silica particles to 1 to 3000, the fluidity of the hollow silica sol when redispersed in the dispersion medium is improved.

[0067] Hollow silica particles are obtained by forming a silica-based shell on the surface of a core-corresponding portion, known as a template, in a dispersion medium, and then removing the core-corresponding portion, resulting in a hollow silica aqueous sol. The metal oxide particles of the present invention can have a hydrophobicity of 30 to 80% by volume, 40 to 80% by volume, 50 to 80% by volume, more than 60 to 80% by volume, 40 to 60% by volume, 30 to less than 60% by volume, or 30 to 50% by volume, as measured by a methanol titration method.

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

[0069] The metal oxide particles of the present invention may be surface-coated with a hydrolysate 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] The silane compound (A) can be at least one silane compound selected from the group represented by the formula (1). １ are chemical groups (a1) each of 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 which are bonded to a silicon atom by a Si—C bond; R ２ are hydrolyzable groups (a2), 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 atom.

[0071] The alkyl group is an alkyl group having 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a cyclopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a cyclobutyl group, a 1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, an n-pentyl group, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a 3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a 1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, a 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 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 a 3-trimethyl-cyclopropyl group, a 1-ethyl-2-methyl-cyclopropyl group, a 2-ethyl-1-methyl-cyclopropyl group, a 2-ethyl-2-methyl-cyclopropyl group, a 2-ethyl-3-methyl-cyclopropyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group.

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

[0073] The acyloxy group is an acyloxy group having 2 to 10 carbon atoms, and examples thereof include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an i-propylcarbonyloxy group, an n-butylcarbonyloxy group, an i-butylcarbonyloxy group, an s-butylcarbonyloxy group, a t-butylcarbonyloxy group, an n-pentylcarbonyloxy group, a 1-methyl-n-butylcarbonyloxy group, a 2-methyl-n-butylcarbonyloxy group, a 3-methyl-n-butylcarbonyloxy group, a 1,1-dimethyl-n-propylcarbonyloxy group, a 1,2-dimethyl-n-propylcarbonyloxy group, a 2,2-dimethyl-n-propylcarbonyloxy group, a 1-ethyl-n-propylcarbonyloxy group, an n-hexylcarbonyloxy group, a 1-methyl-n-pentylcarbonyloxy group, and a 2-methyl-n-pentylcarbonyloxy group, but are not limited to these.

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

[0075] The silane compound (B) can be at least one silane compound selected from the group consisting of the above formula (2) and the above formula (3). 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 the silicon atom by a Si—C bond, and R ５and Y are hydrolyzable groups (b2), each of which is R ５ represents an alkoxy group, an acyloxy group, or a halogen atom, and Y represents an NH group or an oxygen atom. The alkyl group, alkoxy group, acyloxy group, and halogen atom may be the same as those exemplified above. ３ and R ４ The chemical group (b1) is preferably an alkyl group having 1 to 3 carbon atoms, such as a methyl group, an ethyl group, or a propyl group, and preferably a trimethylsilyl group. Examples of the silane compound include the following.

[0076]

[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 group represented by formula (4) above as the silane compound (C). ６ are chemical groups (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 an alkyl group containing a (meth)acryloxy group, and which is bonded to a silicon atom by a Si—C bond; R ７ are hydrolyzable groups (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 atom. In addition to the alkyl groups having 1 to 20 carbon atoms, alkyl groups having 8 to 12 carbon atoms are preferred, such as octyl, nonane, and decyl groups. Examples include octyltrimethoxysilane, nonanetrimethoxysilane, and decyltrimethoxysilane.

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

[0079] The silane compound reacts with the hydroxyl groups on the surface of the silica particles, for example, the silanol groups in the case of silica particles, to coat the surface of the silica particles with the silane compound through siloxane bonds. The reaction temperature can be from 20°C to the boiling point of the dispersion medium, for example, in the range of 20°C to 100°C. The reaction time can be about 0.1 to 10 hours.

[0080] The silane compound is applied to the surface of the silica particles in such an amount that the number of silicon atoms in the silane compound is 0.1 / nm ２ ~20.0 pieces / nm ２ , or 0.1 pieces / nm ２ ~6.0 pieces / nm ２ , or 0.5 pieces / nm ２ ~4.0 pieces / nm ２ , 1 piece / nm ２ ~3.0 pieces / nm ２ The silica particle surfaces can be coated by adding a silane compound corresponding to the coating amount to the silica sol. Water is required for the hydrolysis of the silane compound, and if the sol is an aqueous solvent, that aqueous solvent can be used. When the aqueous medium is replaced with an organic solvent, the water remaining in the solvent can be used. For example, water present in an amount of 0.01 to 5% by mass can be used. Furthermore, the hydrolysis can be carried out with or without a catalyst.

[0081] When the reaction is carried out without a catalyst, the surface of the metal oxide particles is acidic, for example, when the surface of the silica particles is acidic. When a catalyst is used, examples of the hydrolysis catalyst include metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases. Examples of metal chelate compounds used as hydrolysis catalysts include triethoxy mono(acetylacetonato)titanium and triethoxy mono(acetylacetonato)zirconium. Examples of organic acids used as hydrolysis catalysts include acetic acid and oxalic acid. Examples of inorganic acids used as hydrolysis catalysts include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid. Examples of organic bases used as hydrolysis catalysts include pyridine, pyrrole, piperazine, and quaternary ammonium salts. Examples of inorganic bases used as hydrolysis catalysts include sodium hydroxide and potassium hydroxide.

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

[0083] The metal oxide particles of the present invention are coated with the hydrolyzate of the silane compound (A), the hydrolyzate of the silane compound (B), and the hydrolyzate of the silane compound (C), thereby preventing the formation of the silane compound on the surface of the metal oxide particles. ２９When the total of the M structure, D structure, and T structure is taken as 100 mol%, the silane compound can be coated with an M structure (monofunctional, i.e., a structure derived from a silane compound having one hydrolyzable group bonded to the silicon atom and three chemical groups bonded to the silicon atom), a D structure (bifunctional, i.e., a structure derived from a silane compound having two hydrolyzable groups bonded to the silicon atom and two chemical groups bonded to the silicon atom), and a T structure (trifunctional, i.e., a structure derived from a silane compound having three hydrolyzable groups bonded to the silicon atom and one chemical group bonded to the silicon atom) at a ratio of 30 mol% or more and less than 60 mol% for the M structure, 30 mol% or more and less than 90 mol% for the D structure, and 0 mol% or more and less than 30 mol% for the T structure, respectively.

[0084] The metal oxide particles can be dispersed in an organic solvent and / or a reactive monomer to obtain a metal oxide particle sol. The sol can have an average particle size of 5 to 250 nm or 5 to 200 nm as measured by dynamic light scattering. The organic solvent can be selected from alcohols, ketones, ethers, esters, amides, glycols, and hydrocarbons. The organic solvents mentioned above can be used. Examples of reactive monomers include 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, and silanes. The reactive monomer itself can serve as a dispersion medium for the sol, but if it is solid, gaseous, or highly viscous, it can be used as a dispersion medium for the sol by mixing it with an organic solvent. Examples of the acrylic compound include acrylic acid, acrylamide, N,N-dimethylacrylamide, N-(2-hydroxyethyl)acrylamide, diacetone acrylamide, 2-(dimethylamino)ethyl methacrylate, N-isopropylacrylamide, N,N-diethylacrylamide, 4-tert-butylcyclohexyl acrylate, N-[3-(dimethylamino)propyl]acrylamide, N-[3-(dimethylamino)propyl]acrylamide, 4-acryloylmorpholine tetrahydrofurfuryl acrylate, glycol methacrylate, and methacrylic acid monomers. Examples of the allyl compound include allyl alcohol, allyl chloride, allyl ether, allyl glycidyl ether, allyl carboxylic acid, allylamine, allyl isopropyl acetylurea, and allyl acid.

[0085] [Amendment based on Rule 91, 14.04.2025] Examples of isocyanate compounds include aromatic isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, triphenylmethane triisocyanate, tris(isocyanatophenyl)thiophosphate, and p-phenylene diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexyl, dicyclohexylmethane diisocyanate, lysine diisocyanate, and trimethylhexamethylene diisocyanate. Examples of isothiocyanates include allyl isothiocyanate, sulforaphane, benzyl isothiocyanate, p-hydroxybenzyl isothiocyanate, iberin, and phenethyl isothiocyanate.

[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-epoxy Cyclohexane carboxylate, trimethylolethane triglycidyl ether, triglycidyl-p-aminophenol, tetraglycidyl metaxylenediamine, tetraglycidyl diaminodiphenylmethane, tetraglycidyl-1,3-bisaminomethylcyclohexane, bisphenol-A-diglycidyl ether, bisphenol-F-diglycidyl ether, bisphenol-S-diglycidyl ether, pentaerythritol tetraglycidyl ether, resorcinol diglycidyl ether, phthalate 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 polydiglycidyl ether, pentaerythritol polyglycidyl ether, 1,4-bis(2,3-epoxypropoxyperfluoroisopropyl)cyclohexane, sorbitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcinol diglycidyl ether, 1,6-Hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, phenyl glycidyl ether, p-tert-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' ... Examples of epoxy compounds include cyclohexane carboxylate, 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-methylcyclohexane carboxylate, ethylene glycol-bis(3,4-epoxycyclohexane carboxylate), bis-(3,4-epoxycyclohexylmethyl)adipate, and bis(2,3-epoxycyclopentyl)ether. Other examples include bisphenol A liquid epoxy compounds, bisphenol F liquid epoxy compounds, 3',4'-epoxycyclohexylmethyl 3',4'-epoxycyclohexane carboxylate, and tris(2,4-epoxypropyl)isocyanurate.

[0087] Examples of the diamine-containing compound include diamines such as ethylenediamine, putrescine, cadaverine, hexamethylenediamine, and paraphenylenediamine.

[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, and sucrose.

[0089] Examples of dicarboxylic acid-containing compounds 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 of these compounds are also included, such as acetic anhydride, propionic anhydride, oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, benzoic anhydride, etc.

[0090] Disulfonyl chloride-containing compounds include 1,3-benzenedisulfonyl chloride.

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

[0092] Examples of disulfide-containing compounds include dimethyl disulfide, allyl disulfide, and diphenyl disulfide.

[0093] Examples of divinyl-containing compounds include divinylbenzene.

[0094] Diallyl-containing compounds include diallyldimethylammonium chloride.

[0095] The styrene may be a styrene-based compound, such as styrene, 3-acetoxy-5-hydroxystyrene, 4-acetoxystyrene, 3,5-bis(trifluoromethyl)styrene, p-bromostyrene, or p-chlorostyrene.

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

[0097] Examples of bismaleimides include 4,4'-bismaleimide diphenylmethane, phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, and 1,6'-bismaleimide-(2,2,4-trimethyl)hexane.

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

[0099] Examples of lactone ring-containing compounds include beta propiolactone, gamma butyrolactone, delta valerolactone, alpha viron, and coumarin.

[0100] Examples of lactide-containing compounds include L-lactide and D-lactide.

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

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

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

[0104] Silanes include hydrolyzable silane compounds.

[0105] The above metal oxide particles and metal oxide sol can be produced by the following production method, comprising 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), a silane compound (B) selected from the group consisting of formulas (2) and (3), and a basic compound (I) to the metal oxide sol obtained in step (A), and step (C): drying the metal oxide sol obtained in step (B).

[0106] The metal oxide sol can be obtained when step (C) is step (C') or further includes step (D): step (C'): a step of subjecting the metal oxide sol obtained in step (B) to solvent substitution with an organic solvent other than an alcohol having 1 to 5 carbon atoms; and step (D): a step of dispersing the metal oxide particles obtained in step (C) in an organic solvent.

[0107] Furthermore, the above-mentioned metal oxide particles and metal oxide sol can also be produced by the following production method, which includes the following steps (E) to (G): step (E): adding water to a dispersion liquid in which metal oxide particles are dispersed in an organic solvent, step (F): removing the supernatant solvent after step (E) to obtain a precipitate, and step (G): drying the precipitate after step (F) to obtain a metal oxide particle powder. The production method of steps (E) to (G) allows most of the dispersion medium to be removed as the supernatant, so the drying step can be significantly shortened.

[0108] The metal oxide sol is dried at 60°C to 100°C and 50 Torr, and then redispersed in an organic solvent. Regarding the average particle size (nm) of the metal oxide particles in the metal oxide sol measured by dynamic light scattering in the dispersion solvent, the ratio of (average particle size after redispersion measured by dynamic light scattering) / (average particle size before redispersion measured by dynamic light scattering) is 0.6 to 3.0. The drying conditions at 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 can be, for example, 60°C and 50 Torr or 80°C and 50 Torr. Regarding the average particle size (nm) of the metal oxide particles in the metal oxide sol measured by dynamic light scattering in the dispersion solvent after storage at 50°C for 4 weeks, the ratio of (average particle size after storage at 50°C and 50 Torr) / (average particle size before storage at 50°C) is 0.8 to 2.0.

[0109] The present invention provides a dispersion varnish composition containing metal oxide particles and an organic component. Examples of the organic component used in this composition include 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, and at least one monomer selected from silane, or a polymer containing these components. Examples of these organic components include the above-mentioned components.

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

[0111] The organic resin material can be 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. Examples of styrene-based resins include polystyrene, expanded polystyrene, AS resin (styrene-acrylonitrile copolymer), MS resin (styrene-methyl methacrylate copolymer), and ABS resin (styrene-acrylonitrile-butadiene resin).

[0112] Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, aliphatic type epoxy resins, and glycidylamine type epoxy resins.

[0113] The thioepoxy resin 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 also be obtained by copolymerizing a polyisocyanate compound or a polythiol compound.

[0114] Examples of novolac resins include phenol novolac resins, bisphenol A novolac resins, and cresol novolac resins.

[0115] Examples of cyanate-based resins include cyanate ester resins produced from cyanic acid and bisphenol A.

[0116] Examples of phenolic resins include novolak resins obtained from phenol and formaldehyde as raw materials using an acid catalyst, and resol resins obtained using an alkali catalyst.

[0117] Examples of acrylic resins include polymethyl methacrylate, polyacrylic acid esters obtained by copolymerizing methyl methacrylate, methyl methacrylate, styrene, or the like, sodium polyacrylate obtained by copolymerizing sodium acrylate, methyl acrylate, vinyl acetate, or the like, polyacrylonitrile obtained by copolymerizing acrylonitrile, methyl acrylate, methyl methacrylate, or the like, 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-based resins include aliphatic polyesters obtained 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 obtained by polycondensation, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polytrimethylene terephthalate (PTT); and aromatic polyesters obtained 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-based resins include acrylic urethane resins that are made by combining a polyol as a base agent with a polyisocyanate as a curing agent, and that contain an acrylic polyol as a base agent.

[0121] The polyurea resin may be a resin obtained by reacting an isocyanate with a polyamine.

[0122] As the polyimide resin, a resin obtained by the reaction of a carboxylic acid anhydride with a diamine is used, and examples of condensation polymerization type polyimides include pyromellitic acid type polyimide resins, biphenyltetracarboxylic acid type polyimide resins, and benzophenonetetracarboxylic acid type polyimide resins. Examples of addition type polyimides include bismaleimide type polyimide resins, nadic acid-terminated polyimide resins, and acetylene-terminated polyimide resins.

[0123] Polyamide resins are linear polymers formed by amide bonds and may be synthesized by ring-opening polymerization of omega amino acids or by condensation polymerization of diamines and dicarboxylic acids. Examples of such resins include nylon, which contains an aliphatic skeleton, and aramid, which contains only an aromatic skeleton.

[0124] The polyamic acid resin can be a polyamic acid, which is an intermediate polymer of an acid anhydride and a diamine used in polyimide resin synthesis. The polyhydroxyimide resin can be a photosensitive polyimide resin having a hydroxyamide group or a hydroxyimide group. The polybenzoxazole resin can be a thermosetting resin having a benzoxazole ring.

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

[0126] [Correction based on Rule 91, 14 / 04 / 2025] Examples of polybenzoxazine resins include those formed by reacting phenol and bisphenol A with formaldehyde and aromatic amines, and can be cured, for example, by thermal ring-opening polymerization. Examples of polytetrafluoroethylene resins include Teflon®, a polymer of tetrafluoroethylene. Examples of cycloolefin polymer resins include addition copolymers of norbornenes, hydrogenated ring-opening metathesis polymers of norbornenes, transannular polymers of alkylidene norbornenes, addition polymers of norbornenes, hydrogenated 1,2- and 1,4-addition polymers of cyclopentadiene, and ring-opening polymers of conjugated dienes. Examples of unsaturated polyester resins include those obtained by dissolving polyester obtained by the condensation reaction of maleic anhydride and glycol in styrene or methyl methacrylate and then heat-curing the resulting resin.

[0127] An example of a vinyl triazine resin is a resin obtained by polymerizing 2-vinyl-4,6-diamino-1,3,5-triazine. An example of a polyphenylene sulfide resin is a resin having a linear structure in which benzene rings and sulfur atoms are alternately bonded. An example of a cross-linked polyphenylene oxide resin is a polymer alloy of polyphenylene ether, a heat-resistant polyether resin polymerized with 2,6-dimethylphenylene oxide, and polystyrene. In addition to the above-mentioned polyamide resins and polyester resins, examples of condensation resins include starch, phenolic resins, urea resins, melamine resins, polycarbonate resins, and the like.

[0128] Among the above resins, polysiloxane resins can be obtained by hydrolysis of a silane compound followed by dehydration condensation, which can be carried out under the hydrolysis conditions of the silane coupling agent described above.

[0129] The silane compound can be produced by combining 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 bifunctional 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 resin produced by combining a tetrafunctional silane and a trifunctional silane can be mentioned.

[0130] Examples of tetrafunctional silanes include tetraethoxysilane and tetramethoxysilane, with tetraethoxysilane being particularly preferred.

[0131] Examples of trifunctional silanes include alkyl silanes such as methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltriethoxysilane, 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; methacryl silanes such as 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; Examples of the silane include 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 N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, isocyanurate silanes such as tris-(trimethoxysilylpropyl)isocyanurate and diallyl(trimethoxysilylpropyl)isocyanurate, ureido silanes such as 3-ureidopropyltrialkoxysilane, mercapto silanes such as 3-mercaptopropyltrimethoxysilane, and isocyanate silanes such as 3-isocyanatepropyltriethoxysilane.

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

[0133] Examples of polysiloxane resins include polysiloxane resins obtained by copolymerizing tetraethoxysilane, methyltrimethoxysilane, and phenyltrimethoxysilane, and polysiloxane resins 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 1,000 to 100,000, or 1,000 to 5,000.

[0134] For example, the polysiloxane resin can be dissolved in a glycol solvent such as propylene glycol ethyl ether and mixed with silica particles at a blending ratio of 100 phr. The solvent is then replaced with propylene glycol monomethyl ether at 50 Torr and 80°C to produce a varnish as a coating composition. The silica concentration in these coating compositions can be set to 1 to 30% by mass, 5 to 30% by mass, or 3 to 10% by mass. The particle size measured by dynamic light scattering in the coating composition can be set to 10 to 200 nm, 10 to 100 nm, or 30 to 90 nm. For example, when a transparent film is used as a substrate, the coating composition can be applied and dried by heating 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, 0.1 to 30 μm, 1 to 10 μm, or 1 to 3 μm.

[0135] The dielectric constant and dielectric loss tangent of these transparent film-like substrates can be measured. In the present invention, the varnish composition and composite composition described above 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, printing plate materials, printing ink materials, pigments, paints, sealant materials, hard coat materials, 3D printing materials, anti-reflective film materials, structural color forming members, automotive parts materials, electronic parts materials, machine element parts, 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.

[0136] Among the above applications, the use of the particles in thermosetting or photocurable materials, particularly in photosensitive materials, is described below. A film-forming composition can be obtained by selecting and mixing a thermosetting or photocurable organic resin. A cured product can be obtained by adding a curing agent such as an amine-based curing agent, an acid anhydride-based curing agent, a radical generator-based curing agent (thermal radical generator, photoradical generator), or an acid generator-based curing agent (thermal acid generator, photoacid generator). The film-forming composition of the present invention, which contains an organic resin and a curing agent, can be applied or filled onto a substrate and then heated, irradiated with light, or a combination thereof to form a cured product. Examples of organic resins (curable resins) include resins with functional groups such as epoxy groups or (meth)acryloyl groups, and isocyanate-based resins. For example, photocurable polyfunctional acrylates can be preferably used.

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

[0138]

[0139]

[0140]

[0141]

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

[0143] Examples of higher alcohol sulfates include sodium dodecyl sulfate (sodium lauryl sulfate) having 12 carbon atoms, triethanolamine lauryl sulfate, and triethanolammonium lauryl sulfate.

[0144] Examples of 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, etc. Examples of α-olefin sulfonates include sodium α-olefin sulfonate, etc.

[0145] Examples of the alkane sulfonate include sodium 2-ethylhexyl sulfate.

[0146] Examples of the cationic surfactants that can be used in the present invention include alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, and amine salt-based agents.

[0147] Alkyltrimethylammonium salts are quaternary ammonium salts that have chloride ions or bromide ions as counterions. Examples include dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, coconut alkyltrimethylammonium chloride, and alkyl(C16-18)trimethylammonium chloride. Dialkyldimethylammonium salts have two lipophilic main chains and two methyl groups. Examples include bis(hydrogenated tallow)dimethylammonium chloride. Examples include didecyldimethylammonium chloride, dicocoalkyldimethylammonium chloride, dihydrogenated tallow alkyldimethylammonium chloride, and dialkyl(C14-18)dimethylammonium chloride.

[0148] Alkyldimethylbenzylammonium salts are quaternary ammonium salts having one lipophilic main chain, two methyl groups, and a benzyl group, and examples thereof include benzauconium chloride. Examples include alkyl(C8-18)dimethylbenzylammonium chloride. Amine salt agents are those in which the hydrogen atoms of ammonia have been substituted with one or more hydrocarbon groups, and examples thereof include N-methylbishydroxyethylamine fatty acid ester hydrochloride.

[0149] Examples of amphoteric surfactants that can be used in the present invention include N-alkyl-β-alanine-type alkylamino fatty acid salts, alkylcarboxybetaine-type alkylbetaines, and N,N-dimethyldodecylamine oxide-type alkylamine oxides, such as lauryl betaine, stearyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, and lauryldimethylamine oxide.

[0150] The nonionic surfactant used in the present invention is selected from polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, alkyl glucosides, polyoxyethylene fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and fatty acid alkanolamides. Examples of polyoxyethylene alkyl ethers include polyoxyethylene dodecyl ether (polyoxyethylene lauryl ether), polyoxyalkylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyalkylene tridecyl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, polyoxyethylene-2-ethylhexyl ether, and polyoxyethylene isodecyl ether.

[0151] Examples of polyoxyethylene alkylphenol ethers include polyoxyethylene styrenated phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzyl phenyl ether.

[0152] Alkyl glucosides include decyl glucoside and lauryl glucoside.

[0153] Examples of polyoxyethylene fatty acid esters include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol dioleate, polypropylene glycol dioleate, etc. Examples of sorbitan fatty acid esters include sorbitan monocaprylate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan monosesquioleate, and ethylene oxide adducts thereof.

[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, and polyoxyethylene sorbitan triisostearate.

[0155] Examples of fatty acid alkanolamides include coconut oil fatty acid diethanolamide, beef tallow fatty acid diethanolamide, lauric acid diethanolamide, oleic acid diethanolamide, etc. Further examples include polyoxyalkyl ethers or polyoxyalkyl glycols such as polyoxyethylene polyoxypropylene glycol and polyoxyethylene fatty acid esters, polyoxyethylene hydrogenated castor oil ether, sorbitan fatty acid ester alkyl ether, alkyl polyglucoside, sorbitan monooleate, and sucrose fatty acid esters.

[0156] Silicone surfactants can be used. Silicone surfactants are compounds having a repeating unit containing a siloxane bond in the main chain. The weight-average molecular weight of the silicone surfactants can be in the range of 500 to 50,000. These may be modified silicone surfactants, and examples of such surfactants include those having an organic group introduced into the side chain and / or terminal of a polysiloxane. Examples of organic groups include amino groups, epoxy groups, alicyclic epoxy groups, carbinol groups, mercapto groups, carboxyl groups, aliphatic ester groups, aliphatic amide groups, and polyether groups. Examples of silicone surfactants include trade names such as Toray Silicone DC3PA, Toray Silicone SH7PA, Toray Silicone DC11PA, Toray Silicone SH21PA, Toray Silicone SH28PA, Toray Silicone SH29PA, Toray Silicone SH30PA, and Toray Silicone SH8400 (all manufactured by Dow Corning Toray Co., Ltd.), Silwet 1-77, L-7280, L-7001, L-7002, L-7200, L-7210, L-7220, L-7230, L7500, L-7600, L-7602, L-7604, L-7605, L-7622, ​​L-765 7, L-8500, and L-8610. (all manufactured by Momentive Performance Materials), KP-341, KF-6001, KF-6002 (all manufactured by Shin-Etsu Silicones Co., Ltd.), BYK307, BYK323, BYK330 (all manufactured by BYK-Chemie). For example, a polyether-modified silicone under the trade name L-7001 (manufactured by Dowsil Industries) can be suitably used.

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

[0158] Examples of heat curing agents include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polymercaptans, acid anhydrides, thermal radical generators, and thermal acid generators. Radical generator-based curing agents, acid anhydride-based curing agents, and amine-based curing agents are particularly preferred. These solid heat curing agents can be used by dissolving them in a solvent, but evaporation of the solvent can reduce the density of the cured product and create pores, resulting in reduced strength and reduced water resistance. Therefore, it is preferable for the curing agent itself to be liquid at room temperature and normal pressure. Examples of phenolic resins include phenol novolac resins and cresol novolac resins.

[0159] Examples of amine curing agents include piperidine, N,N-dimethylpiperazine, triethylenediamine, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, menthenediamine, isophoronediamine, diaminodicyclohexylmethane, 1,3-diaminomethylcyclohexane, xylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and diethyltoluenediamine. Of these, liquids such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, menthenediamine, isophoronediamine, diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and diethyltoluenediamine can be preferably used.

[0160] The polyamide resin is produced by 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 imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and epoxyimidazole adduct.

[0162] The polymercaptan is, for example, one in which a mercaptan group is present at the end of a polypropylene glycol chain or one in which a mercaptan group is present at the end of a polyethylene glycol chain, and is preferably liquid. The acid anhydride curing agent is preferably an anhydride of a compound having multiple carboxyl groups in one molecule. Examples of these acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, ethylene glycol bistrimellitate, glycerol tristrimellitate, maleic anhydride, tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, endomethylene tetrahydrophthalic anhydride, methyl endomethylene tetrahydrophthalic anhydride, methylbutenyl tetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylcyclohexene dicarboxylic anhydride, and chlorendic anhydride. Examples of thermal acid generators include sulfonium salts and phosphonium salts, with sulfonium salts being preferred. For example, the following compounds can be mentioned.

[0163]

[0164] R may be an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 20 carbon atoms, and is particularly preferably an alkyl group having 1 to 12 carbon atoms.

[0165] Among these, methyltetrahydrophthalic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride (methylnadic anhydride, methylhimic anhydride), hydrogenated methylnadic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, methylhexahydrophthalic anhydride, and a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, which are liquid at room temperature and normal pressure, are preferred. These liquid acid anhydrides have a viscosity of about 10 mPa·s to 1,000 mPa·s when measured at 25°C. Examples of thermal radical generators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methylpropionate)dimethyl, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, tert-butyl hydroperoxide, cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, and benzoyl peroxide. These are available from Tokyo Chemical Industry Co., Ltd.

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

[0167] A thermosetting varnish is obtained by mixing the composition with a resin, a curing agent, and optionally, a curing aid. These components can be mixed in a reaction vessel using a stirring blade or kneader. Mixing is performed by a heated mixing method at a temperature of 60°C to 100°C for 0.5 to 1 hour. The resulting thermosetting film-forming composition is a thermosetting coating composition and has an appropriate viscosity for use, for example, as a liquid encapsulant. Liquid thermosetting film-forming compositions can be prepared to any viscosity and can be used as transparent encapsulants for LEDs and other devices by casting, potting, dispensing, printing, or other methods, allowing for partial encapsulation at any desired location. The liquid thermosetting composition is directly mounted on an LED or other device using the method described above, followed by drying and curing to obtain a cured product.

[0168] A thermosetting film-forming composition (thermosetting coating composition) is applied to a substrate and heated at a temperature of 80 to 200°C to obtain a cured product. In the case of a photocurable resin composition, a photocuring agent (photoradical generator, photoacid generator) can be added in a range of 0.01 to 50 phr, or 0.01 to 10 phr, to a resin containing a functional group such as an epoxy group or a (meth)acryloyl group. For example, the photocuring agent (photoradical generator, photoacid generator) can be added in a ratio of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, to the functional group such as an epoxy group or a (meth)acryloyl group. The equivalent of the photocuring agent relative to the curable resin is expressed as the equivalent ratio of the photocuring agent to the functional group. The photoradical generator is not particularly limited, as long as it generates radicals directly or indirectly upon light irradiation.

[0169] Examples of photoradical generators include photoradical polymerization initiators. Examples of photoradical polymerization initiators include imidazole compounds, diazo compounds, bisimidazole compounds, N-arylglycine compounds, organic azide compounds, titanocene compounds, aluminate compounds, organic peroxides, N-alkoxypyridinium salt compounds, and thioxanthone compounds. Examples of azide compounds include p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, 4,4'-diazidochalcone, 4,4'-diazidodiphenyl sulfide, and 2,6-bis(4'-azidobenzal)-4-methylcyclohexanone. Examples of diazo compounds include 1-diazo-2,5-diethoxy-4-p-tolylmercaptobenzeneborofluoride, 1-diazo-4-N,N-dimethylaminobenzene chloride, and 1-diazo-4-N,N-diethylaminobenzeneborofluoride. Examples of bisimidazole compounds include 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)1,2'-bisimidazole and 2,2'-bis(o-chlorophenyl)4,5,4',5'-tetraphenyl-1,2'-bisimidazole.Examples of titanocene compounds include dicyclopentadienyl-titanium-dichloride, dicyclopentadienyl-titanium-bisphenyl, dicyclopentadienyl-titanium-bis(2,3,4,5,6-pentafluorophenyl), dicyclopentadienyl-titanium-bis(2,3,5,6-tetrafluorophenyl), dicyclopentadienyl-titanium-bis(2,4,6-trifluorophenyl), dicyclopentadienyl-titanium-bis(2,6-difluorophenyl), dicyclopentadienyl bis(methylcyclopentadienyl)-titanium-bis(2,3,4,5,6-pentafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,3,5,6-tetrafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,6-difluorophenyl), and dicyclopentadienyl-titanium-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl).

[0170] Further examples of the photoradical generator include 1,3-di(tert-butyldioxycarbonyl)benzophenone, 3,3',4,4'-tetrakis(tert-butyldioxycarbonyl)benzophenone, 3-phenyl-5-isoxazolone, 2-mercaptobenzimidazole, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone.

[0171] These photoradical polymerization agents are available, for example, as Irgacure TPO (component: 2,4,6-trimethylbenzoyldiphenylphosphine oxide) (c1-1-1), manufactured by BASF, Omnirad 819 (component: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) (c1-1-2), manufactured by IGM RESINS, and Irgacure 184 (component: 1-hydroxycyclohexylphenyl ketone) (c1-1-3).

[0172]

[0173] The photoacid generator is not particularly limited as long as it generates an acid directly or indirectly upon irradiation with light. Specific examples of the photoacid generator include triazine compounds, acetophenone derivative compounds, disulfone compounds, diazomethane compounds, sulfonic acid derivative compounds, onium salts such as iodonium salts, sulfonium salts, phosphonium salts, and selenium salts, metallocene complexes, and iron arene complexes. The onium salt used as the photoacid generator includes iodonium salts such as diphenyliodonium chloride, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium mesylate, diphenyliodonium tosylate, diphenyliodonium bromide, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsenate, bis(p-tert-butylphenyl)iodonium hexafluorophosphate, bis(p-tert-butylphenyl)iodonium mesylate, bis(p-tert-butylphenyl)iodonium tosylate, bis(p-tert-butylphenyl)iodonium trifluoromethanesulfonate, bis(p-tert-butylphenyl)iodonium Examples of the iodonium salt include bis(alkylphenyl)iodonium salts such as iodonium tetrafluoroborate, bis(p-tert-butylphenyl)iodonium chloride, bis(p-chlorophenyl)iodonium chloride, bis(p-chlorophenyl)iodonium tetrafluoroborate, and further bis(4-t-butylphenyl)iodonium hexafluorophosphate; alkoxycarbonylalkoxy-trialkylaryl iodonium salts (for example, 4-[(1-ethoxycarbonyl-ethoxy)phenyl]-(2,4,6-trimethylphenyl)-iodonium hexafluorophosphate); and bis(alkoxyaryl)iodonium salts (for example, bis(alkoxyphenyl)iodonium salts such as (4-methoxyphenyl)phenyliodonium hexafluoroantimonate).Examples of sulfonium salts include triphenylsulfonium salts such as triphenylsulfonium chloride, triphenylsulfonium bromide, tri(p-methoxyphenyl)sulfonium tetrafluoroborate, tri(p-methoxyphenyl)sulfonium hexafluorophosphonate, tri(p-ethoxyphenyl)sulfonium tetrafluoroborate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, and triphenylsulfonium hexafluorophosphate; and sulfonium salts such as (4-phenylthiophenyl)diphenylsulfonium hexafluoroantimonate, (4-phenylthiophenyl)diphenylsulfonium hexafluorophosphate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluoroantimonate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluorophosphate, and (4-methoxyphenyl)diphenylsulfonium hexafluoroantimonate.

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

[0175] The following compounds can also be used as photoacid generators.

[0176]

[0177]

[0178]

[0179]

[0180]

[0181]

[0182]

[0183]

[0184]

[0185] As the photoacid generator, sulfonium salt compounds and iodonium salt compounds are preferred. The anion species thereof is CF ３ SO ３ － , C ４ F ９ SO ３ － , C ８ F １７ SO ３ － , camphorsulfonate anion, tosylate anion, BF ４ － , P.F. ６ － , AsF ６ － and SbF ６ － and the like. Anion species such as phosphorus hexafluoride and antimony hexafluoride, which exhibit strong acidity, are particularly preferred. The film-forming composition of the present invention may contain conventional additives as needed. Examples of such additives include pigments, colorants, thickeners, sensitizers, antifoaming agents, coatability improvers, lubricants, stabilizers (antioxidants, heat stabilizers, light resistance stabilizers, etc.), plasticizers, dissolution promoters, fillers, antistatic agents, and the like. These additives may be used alone or in combination of two or more.

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

[0187] When a photoacid generator is used, the light to be irradiated or exposed may be, for example, gamma rays, X-rays, ultraviolet light, or visible light, and is usually visible light or ultraviolet light, particularly ultraviolet light. The wavelength of the light is, for example, about 150 to 800 nm, preferably about 150 to 600 nm, and more preferably about 150 to 400 nm. The amount of irradiation light varies depending on the thickness of the coating film, but is, for example, about 2 to 20,000 mJ / cm. 2 , preferably 5 to 5000 mJ / cm 2The light source can be selected depending on the type of light to be exposed. For example, in the case of ultraviolet light, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a deuterium lamp, a halogen lamp, or laser light (e.g., a helium-cadmium laser or an excimer laser) can be used. Such light irradiation causes the curing reaction of the composition to proceed. When a thermal acid generator is used, or when a photoacid generator is used, heating of the coating film, which is optionally performed after light irradiation, is carried out at, for example, 60 to 350°C, preferably about 100 to 300°C. The heating time can be selected from the range of 3 seconds or more (e.g., about 3 seconds to 5 hours), for example, 5 seconds to 2 hours, preferably about 20 seconds to 30 minutes, and typically about 1 minute to 3 hours (e.g., about 5 minutes to 2.5 hours).

[0188] Furthermore, when forming a pattern or image (for example, when producing a printed wiring board, etc.), the coating film formed on the substrate may be subjected to pattern exposure. This pattern exposure may be performed by scanning with laser light or by irradiating with light through a photomask. The non-irradiated areas (unexposed areas) generated by such pattern exposure are developed (or dissolved) with a developer to form a pattern or image. Examples of the developer include aqueous alkaline solutions and organic solvents. Examples of aqueous alkaline solutions include aqueous solutions of alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, potassium carbonate, and sodium carbonate; aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, tetraethylammonium hydroxide, and choline; and aqueous amine solutions such as ethanolamine, propylamine, and ethylenediamine.

[0189] The alkaline developer is generally an aqueous solution of 10% by weight or less, preferably a 0.1 to 3.0% by weight aqueous solution. Furthermore, alcohols or surfactants can be added to the developer, each of which is preferably added in an amount of 0.05 to 10 parts by weight per 100 parts by weight of the developer. Among these, a 0.1 to 2.38% by weight aqueous solution of tetramethylammonium hydroxide or ethyltrimethylammonium hydroxide can be used. Furthermore, the organic solvent used in the developer can be a common organic solvent, such as acetone, acetonitrile, toluene, dimethylformamide, methanol, ethanol, isopropanol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol butyl ether acetate, ethyl lactate, or cyclohexanone. These can be used alone or in combination. 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 adhesion to the substrate after development. These adhesion promoters include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, and chloromethyldimethylchlorosilane, alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, and phenyltriethoxysilane, silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, and trimethylsilylimidazole, vinyltrichlorosilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane. Examples of suitable adhesion promoters include silanes such as aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-(N-piperidinyl)propyltrimethoxysilane; heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and urea or thiourea compounds such as 1,1-dimethylurea and 1,3-dimethylurea. These adhesion promoters can be used alone or in combination of two or more. The amount of these adhesion promoters added is typically 18% by mass or less, preferably 0.0008 to 9% by mass, and more preferably 0.04 to 9% by mass, based on the solid content.

[0191] The present invention may contain a sensitizer. Usable sensitizers include anthracene, phenothiazene, perylene, thioxanthone, and benzophenone thioxanthone. Further examples of sensitizing dyes include thiopyrylium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, and pyrylium salt dyes. Anthracene sensitizers are particularly preferred. When used in combination with a cationic curing catalyst (a radiation-sensitive cationic polymerization initiator), they dramatically improve sensitivity and also possess radical polymerization initiation capabilities. In hybrid systems that combine the cationic curing system of the present invention with a radical curing system, the catalyst species can be simplified. Specific anthracene compounds that are effective include dibutoxyanthracene and dipropoxyanthraquinone. The amount of the sensitizer added is 0.01 to 20% by mass, preferably 0.01 to 10% by mass, based on the solid content. The composition of the present invention can be photocured or thermally cured using a photoradical generator, a thermal radical generator, a photoacid generator, or a thermal acid generator. When a photoacid generator or a thermal acid generator is used, for example, commonly used epoxy curing agents (e.g., amines or acid anhydrides) are not used, or even if they are used, the content of these agents is extremely small, thereby improving the storage stability of the composition.

[0192] The above composition has been found to be applicable to photocationic polymerization. It has a higher curing rate than conventional liquid epoxy compounds (e.g., alicyclic epoxy compounds with an epoxycyclohexyl ring). Because of its fast curing rate, it is possible to reduce the amount of acid generator added or use a weak acid generator. Reducing the amount of acid generator is important for preventing metal corrosion, as active acid species may remain even after UV irradiation. Because of its fast curing rate, thick film curing is possible. Curing by UV irradiation can be applied to materials (equipment) that are sensitive to heat.

[0193] Thermosetting and photocurable materials using the film-forming composition of the present invention are characterized by rapid curing, transparency, and minimal cure shrinkage, and can be used for coating and bonding electronic components, optical components (anti-reflective coatings), and precision mechanical parts. The present invention allows the coating composition to contain silica particles that are redispersible in developers containing organic solvents or alkaline aqueous solutions. Hollow silica particles can be soluble in developers based on the surface potential present on their surfaces, but by attaching organic functional groups to the surface, they can be selectively developable only with organic solvents or only with alkaline aqueous solutions. These organic functional groups can be achieved by coating the silica particles with the aforementioned silane coupling agent, adding an amine to the silica sol, or adding a surfactant.

[0194] The present invention will be described in more detail below 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-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: MeOH-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: MeOH-dispersed silica sol with an average primary particle size of 45 nm (manufactured by Nissan Chemical Industries, Ltd., MeOH-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 Industries, 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 Co., Ltd., 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 Co., Ltd., 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 compounds) DiPA: diisopropylamine DiPEA: diisopropylethylamine 1% by mass aqueous solution of sodium hydroxide

[0199] (Additives) MEHQ: 4-methoxyphenol According to the following methods, the physical properties of the above water-dispersed silica sol, the dispersions of surface-modified silica particles prepared in the examples and comparative examples, and the silica sol and dispersions during the dispersion production process were measured and evaluated.

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

[0201] (Method for Measuring pH of Water-Dispersed Metal Oxide Sol) The pH of the water-dispersed metal oxide sol was measured using a pH meter (manufactured by DKK Toa Corporation, product name: MM-43X).

[0202] (Method for measuring pH of organic solvent-dispersed metal oxide sol) The pH of the organic solvent-dispersed metal oxide sol was measured using a pH meter (manufactured by DKK-TOA Corporation, product name: MM-43X) to measure a liquid obtained by mixing a target sample containing the organic solvent-dispersed metal oxide sol with MeOH and pure water in a mass ratio of 1:1:1.

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

[0204] (Organic Solvent Content) The organic solvent content in the metal oxide sol was measured using a gas chromatograph (Shimadzu Corporation, product name: GC-2014s) under the following conditions: Column: 3 mm x 1 m glass column Filler: Polar Pack Q (product name) Column temperature: 130 to 230°C (heating rate: 8°C / min) Carrier: N ２ 40 mL / min. Detector: FID Injection volume: 1 μL Internal standard: acetonitrile was used.

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

[0206] (Measurement of redispersion sol viscosity (EMS viscosity)) The viscosity of the redispersion solvent (redispersion sol) obtained by mixing a dry powder obtained by drying metal oxide particles or a metal oxide sol with a solvent was measured using an EMS viscometer (manufactured by Kyoto Electronics Co., Ltd., product name EMS-1000S). The measurement was carried out at a temperature of 20°C.

[0207] (specific surface area by nitrogen adsorption method (S Ｎ２ Measurement of the specific surface area (S) of metal oxide particles by nitrogen adsorption method Ｎ２ The specific surface area of ​​a water-dispersed metal oxide sol was measured by removing water-soluble cations in the water-dispersed metal oxide sol with a cation exchange resin (manufactured by The Dow Chemical Company, trade name: Amberlite IR-120B), and then drying the metal oxide sol at 290°C to prepare a measurement sample. The specific surface area of ​​the sample was measured using a Monosorb (manufactured by Quantachrome Instruments Japan, LLC) which is a nitrogen adsorption method specific surface area measuring device.

[0208] (Average primary particle diameter) The average primary particle diameter of the metal oxide particles is determined by the specific surface area S Ｎ２ (m ２ When the metal oxide particles are silica particles, the average primary particle diameter is calculated from the specific surface area S Ｎ２ (m ２The average primary particle diameter was calculated by converting the average particle diameter (g) of the particles into spherical particles using the following formula:

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

[0210] (Average Particle Diameter by DLS Method (Average Particle Diameter by Dynamic Light Scattering Method)) The average particle diameter by DLS method was measured using a dynamic light scattering particle size analyzer (manufactured by Malvern Panalytical, product name: Zetasizer Nano). The particle refractive index, solvent refractive index, solvent viscosity, etc. were set according to the measurement sample, and the measurement temperature was adjusted to match the solvent refractive index and solvent viscosity used. 0.1 g of the target metal oxide sol was dispensed into a glass cell with an optical path length of 10 mm, and a solvent identical to 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 when the attenuator indicated 7 was 200 to 400 kcps. For example, in the case of an 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 when the attenuator indicated 7 was 200 to 400 kcps. The prepared metal oxide sol was placed in the cell so that the height of the liquid surface from the bottom of the cell was adjusted to about 1 cm, and the average particle size of the metal oxide sol was measured by dynamic light scattering when the attenuator indicated 7. The Z-average particle size was used as the average particle size measured by dynamic light scattering.

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

[0212] 2) Preparation of Metal Oxide Particle-Blended Film The metal oxide particle aqueous sol-blended varnish obtained in 1) (blended amount (metal oxide): 50 phr, 100 phr, 150 phr) was irradiated with UV- ３ Approximately 1 mL of the solution was dropped onto the treated Si substrate and uniformly spread on the Si substrate using a spin coater (Mikasa Co., Ltd., Opticoat MS-B100) under the following conditions: increase to 200 rpm over 2 seconds, 200 rpm x 10 seconds, increase to 800 rpm over 2 seconds, 800 rpm x 5 seconds, and decrease to 0 rpm over 5 seconds. The solution was then 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 metal oxide particle-blended films (metal oxide blending amounts: 50 phr, 100 phr, 150 phr).

[0213] 3) Measurement of refractive index of metal oxide particle-blended film, calculation of refractive index of metal oxide particles The refractive index of the metal oxide particle-blended film obtained in 2) (metal oxide blending amount: 50 phr, 100 phr, 150 phr) was measured using an ellipsometer (VASE multi-angle spectroscopic ellipsometer manufactured by J.A. Woollam Japan Co., Ltd.). Separately, the refractive index of a film containing no metal oxide particles, which was similarly prepared using only a partial hydrolyzate of GPS, was also measured. The measured refractive index of the blended film was plotted against the blending amount of metal oxide particles, and the refractive index of the metal oxide particles was calculated by extrapolating so that the blending amount of metal oxide particles was 100% by mass.

[0214] (Hydrophobicity Measurement) 5 mL of metal oxide sol was evaporated and distilled off in a rotary evaporator at a reduced pressure of 50 Torr and a bath temperature of 80 to 130°C (120°C for DMAC-dispersed silica sol) to obtain a metal oxide powder. The obtained powder was pulverized in a mortar and dried again in a rotary evaporator at a reduced pressure of 50 Torr and a bath temperature of 130°C to obtain a sample for hydrophobicity measurement. 50 mL of pure water was placed in a 100 mL beaker, and 0.2 g of the metal oxide powder was added and stirred using a magnetic stirrer. Methanol was then added dropwise, and the hydrophobicity was calculated using the following formula based on the amount of methanol added (X mL) required for the metal oxide powder floating on the liquid surface to be completely submerged in the liquid. Hydrophobicity (volume %) = {(X) / (50 + X)} × 100

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

[0216] (Measurement of Composition Concentration) The concentration (mass %) of the composition was calculated by measuring approximately 1.00 g of the composition into an aluminum cup, baking it at 200° C. for 2 hours, and weighing the baking residue.

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

[0218] (Measurement of D10, D50, and D90) D10, D50, and D90 were measured by photographing particles in the metal oxide using a transmission electron microscope (manufactured by JEOL Ltd., trade name JEM-F200), binarizing approximately 300 arbitrarily selected particles using an automatic image processing analyzer (manufactured by Nireco Corporation, trade name LUZEX AP), and measuring D10, D50, and D90 of the metal oxide sol as a particle size distribution from the diameter obtained by converting the projected area into a circle. D10, D50, and D90 were measured by a volume distribution method as particle sizes representing 10%, 50%, and 90% of the cumulative particle size distribution from the fine particle side.

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

[0220] (Measurement of the amount of aluminum (B) present in the entire silica particles / dissolution method) A precisely weighed amount of silica sol was dried, and 250 mg of the obtained particles were dissolved in 2.5 ml of nitric acid (manufactured by Kanto Chemical Co., Inc., trade name: nitric acid 1.38, purity 60.0%) and 2.5 ml of 38% hydrofluoric acid (manufactured by Tama Chemicals Co., Ltd., trade name: hydrofluoric acid) to obtain an aqueous solution. The amount of aluminum in the obtained aqueous solution was measured using an ICP emission spectrometer (manufactured by Rigaku Corporation, trade name: CIROS120 EOP), and the amount of aluminum present in the entire silica particles was determined as Al ２ O ３ Converted to SiO ２ (Al ２ O ３ (ppm) / SiO ２ ) was sought.

[0221] (Measurement of the amount of aluminum (A) bound to the silica particle surface / Leaching method) Cationic components in the silica sol were removed using an H-type cation exchange resin, and the dried product, from which the solvent was removed 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 placed in a polypropylene container (PP sampler bottle, 50 mL) containing 20 mL of 0.1 mol / L (N / 10) aqueous nitric acid solution, and vigorously shaken and mixed by hand. Next, ultrasonic treatment was performed for 10 minutes in an ultrasonic cleaner (manufactured by AS ONE, product name ASU CLEANER ASU-10M) to thoroughly blend the powder with the aqueous nitric acid solution. The powder was then placed in a 50°C thermostatic bath and maintained for 17 hours. Thereafter, the solution was cooled to room temperature and charged into a centrifugal ultrafiltration filter (trade name Amicon Ultra-15, molecular weight cutoff 10,000). The amount of aluminum in the filtrate obtained by centrifugation was measured using an ICP emission spectrometer. The amount of aluminum bound to the silica particle surface was determined as Al ２ O ３ Converted to SiO ２ (Al ２ O ３ (ppm) / SiO ２ ) was sought.

[0222] (Measurement of Surface Charge Amount of Metal Oxide Particles) A ​​metal oxide sol was added to 10 mL of MeOH and diluted to a metal oxide concentration of 0.5 mass %, to prepare a measurement sample. Using a particle charge meter (manufactured by Voith Turbo K.K., product name PCD-06), a 0.001 mol / L (N / 1000) DADMAC solution (manufactured by Voith Turbo K.K.) as a standard cation titrant, the titration value until the streaming potential of the measurement sample reached zero was measured. The obtained titration value was divided by the mass of the metal oxide contained in the measurement sample, and the value converted to a value per 1 g of metal oxide particles was determined as the surface charge amount (μeq / g-SiO ２ ) where DADMAC represents poly(diallyldimethylammonium chloride).

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

[0224] (Synthesis Example 1) Synthesis of MeOH Dispersion of Surface-Modified Solid Silica Particles (1) 200 g of MA-ST-L (Nissan Chemical Industries, Ltd., trade name) 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 maintained for 3 hours. Next, 6.61 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Thereafter, DiPA was added so that the pH was 8.3, and the mixture was heated to 60 ° C. and maintained for 1 hour to obtain the target sol. The obtained methanol-dispersed solid silica sol using MeOH as a dispersion medium had an average particle size of 85 nm by 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 the mixture showed good dispersibility.

[0225] Synthesis Example 2 Synthesis of MEK Dispersion of Surface-Modified Solid Silica Particles (2) 60.0 g of the MeOH dispersion of surface-modified silica particles (1) obtained in Synthesis Example 1 was placed in a 200 ml eggplant-shaped flask, placed in a rotary evaporator, and distilled while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, thereby replacing the dispersion medium with MEK, to obtain the target sol. The obtained MEK-dispersed solid silica sol using MEK as the dispersion medium had an average particle size of 80 nm as determined by DLS, a pH of 7.6, a silica concentration of 41.6% by mass, a water content of less than 0.1% by mass, and an MeOH content of less than 0.1% by mass. Furthermore, no sediment was observed, demonstrating good dispersibility.

[0226] Synthesis Example 3 Synthesis of MEK Dispersion (3) of Surface-Modified Solid Silica Particles 50 g of MA-ST-L (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in a 200 ml eggplant-shaped flask, and while stirring with a magnetic stirrer, 7.5 g of MEK, 1.11 g of HCl (particle unit surface area (nm ２ MPDMS (equivalent to 3 MPDMS molecules per phase) was added, heated to 60°C, and maintained for 3 hours. Next, 1.65 g of TMSO was added, heated to 60°C, and maintained for 3 hours. DiPA was then added so that the pH was 8.4, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the resulting sol was placed in a rotary evaporator, and distillation was performed while supplying MEK at a bath temperature of 80°C and a reduced pressure of 550 to 350 Torr. The dispersion medium was replaced with MEK, and the target sol was obtained. The resulting MEK-dispersed solid silica sol using MEK as the dispersion medium had an average particle size of 79 nm as determined by DLS, a pH of 7.3, a silica concentration of 42.7% by mass, a water content of less than 0.1% by mass, and an MeOH content of less than 0.1% by mass. There was no sediment, and the mixture exhibited good dispersibility.

[0227] (Synthesis Example 4) Synthesis of MEK Dispersion (4) of Surface-Modified Solid Silica Particles The amount of MPDMS added in Synthesis Example 3 was changed to 0.74 g (unit surface area of ​​particles (nm ２The target sol was obtained in the same manner as in Synthesis Example 3, except that the number of MPDMS molecules per phase was adjusted to correspond to two. The obtained MEK-dispersed solid silica sol using MEK as the dispersion medium had an average particle size of 80 nm as determined by the DLS method, a pH of 7.7, a silica concentration of 40.0% by mass, a water content of less than 0.1% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the sol exhibited good dispersibility.

[0228] (Synthesis Example 5) Synthesis of MEK Dispersion (5) of Surface-Modified Solid Silica Particles The amount of MPDMS added in Synthesis Example 3 was 0.37 g, and the unit surface area (nm ２ The target sol was obtained in the same manner as in Synthesis Example 3, except that the amount of MPDMS molecule was one per 1000 MPDMS molecules (equivalent to one MPDMS molecule ...)). The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 79 nm as determined by DLS, a pH of 7.6, a silica concentration of 41.0% by mass, a water content of less than 0.1% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the sol exhibited good dispersibility.

[0229] Synthesis Example 6 Synthesis of MEK Dispersion of Surface-Modified Solid Silica Particles (6) 100 g of MA-ST-L (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in 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 maintained for 2 hours. Thereafter, the eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 90°C and under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining an MEK dispersion with a silica concentration of 40.5 mass%. Furthermore, 50 g of the obtained MEK dispersion was placed in 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 maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 8.4, and the mixture was heated to 60°C and maintained for 1 hour to obtain the target sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 90 nm as determined by the DLS method, a pH of 5.4, a silica concentration of 40.1% by mass, a water content of 0.1% by mass, and an MeOH content of 0.2% by mass. No sediment was observed, demonstrating good dispersibility.

[0230] Synthesis Example 7 Synthesis of MEK Dispersion of Surface-Modified Solid Silica Particles (7) 50 g of MA-ST-L (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in 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 maintained for 3 hours. Next, 0.52 g of DTMS was added, and the mixture was heated to 60°C and maintained for 3 hours. Next, 1.60 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPA was added so that the pH became 8.4, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the desired sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 79 nm as determined by DLS, a pH of 7.8, a silica concentration of 39.1% by mass, a water content of less than 0.1% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0231] Synthesis Example 8 Synthesis of MeOH Dispersion of Solid Silica (8) 14,000 g of Snowtex O-40 (trade name, manufactured by Nissan Chemical Industries, Ltd.) was subjected to water substitution by ultrafiltration using MeOH, and the substitution was stopped when the water content reached 0.5% by mass, to obtain a MeOH-dispersed solid silica sol. The physical properties of the obtained sol were silica concentration 40.6% by mass, water content 0.5% by mass, viscosity 5.4 mPa s, average particle diameter by DLS method 56 nm, and the amount of Na present in the entire silica particles was Na ２ SiO of silica converted to O ２ The ratio of the mass of SiO to the mass of ２ The amount of sulfate ions present in the silica sol is ４ Converted to SiO ２ 0.7 ppm / SiO ２ The amount of aluminum present in the entire silica particle was Al ２ O ３ Converted to SiO ２ 2500 ppm / SiO ２ It was.

[0232] Synthesis Example 9 Synthesis of MEK Dispersion (9) of Surface-Modified Solid Silica Particles 200 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was placed in 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, and the mixture was heated to 60°C and maintained for 3 hours. Next, 13.39 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPA was added so that the pH became 8.4, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, replacing the dispersion medium with MEK to obtain the desired sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 39 nm as measured by DLS, a pH of 7.7, a silica concentration of 37.6% by mass, a water content of less than 0.1% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0233] Synthesis Example 10 Synthesis of MEK Dispersion (10) of Surface-Modified Solid Silica Particles 350 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was placed in 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, and the mixture was heated to 60°C and maintained for 3 hours. Next, 23.41 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPA was added so that the pH became 8.4, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the target sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 35 nm as measured by DLS, a pH of 8.3, a silica concentration of 41.0% by mass, a water content of 0.2% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0234] Synthesis Example 11 Synthesis of MEK Dispersion (11) of Surface-Modified Solid Silica Particles 300 g of MT-ST (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in 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 maintained for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPA was added so that the pH became 8.4, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was set in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the target sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 15 nm as measured by DLS, a pH of 9.3, a silica concentration of 30.5% by mass, a water content of 0.1% by mass, and an MeOH content of 0.2% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0235] (Synthesis Example 12) Synthesis of PGME Dispersion of Surface-Modified Solid Silica Particles (12) 300 g of PGM-ST (Nissan Chemical Industries, Ltd., trade name) was charged into a 1000 ml eggplant-shaped flask, and 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 maintained for 3 hours. Next, 38.8 g of TMS was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Thereafter, DiPEA was added so that the pH was 8.4, and the mixture was heated to 60 ° C. and maintained for 1 hour to obtain the target sol. The obtained PGME-dispersed solid silica sol using PGME as a dispersion medium had an average particle size of 19 nm by DLS method, a pH of 9.1, and a silica concentration of 28.2% by mass. There was no sediment and the mixture showed good dispersibility.

[0236] Synthesis Example 13 Synthesis of MeOH Dispersion of Solid Silica Particles (13) 1000 g of ST-ZL (trade name, manufactured by Nissan Chemical Industries, Ltd.) was passed through a column packed with a cation exchange resin (trade name: Amberlite IR-120B, manufactured by The Dow Chemical Company) at a space velocity of 10 per hour to remove cations, and a water-dispersed silica sol with a pH of 3.3 was obtained. 800 g of the obtained water-dispersed silica sol was charged into a 2 L glass reactor equipped with a stirrer, a condenser, a thermometer, and two inlets. While the sol in the reactor was boiling, methanol vapor generated in a separate boiler was continuously blown into the silica sol in the reactor to perform water replacement with methanol. The replacement was terminated when the volume of the distillate reached 9 L, and 870 g of a methanol-dispersed solid 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 dispersion (14) of surface-modified solid silica particles 400 g of the MeOH dispersion (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 maintained for 3 hours. Next, 6.36 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Thereafter, DiPA was added so that the pH was 8.3, and the mixture was heated to 60 ° C. and maintained for 1 hour. The obtained methanol-dispersed solid silica sol using methanol as a dispersion medium had an average particle size of 134 nm by 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 the mixture showed good dispersibility.

[0238] Synthesis Example 15 Synthesis of MEK Dispersion (15) of Surface-Modified Solid Silica Particles The eggplant-shaped flask containing the sol obtained in Synthesis Example 14 was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the target sol. The obtained MEK-dispersed solid silica sol using MEK as the dispersion medium had an average particle size of 129 nm as determined by DLS, a pH of 6.8, a silica concentration of 28.2% by mass, a water content of 0.1% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the sol showed good dispersibility.

[0239] (Synthesis Example 16) Synthesis of MEK dispersion (16) of surface-modified solid silica particles 400 g of the MeOH dispersion (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 maintained for 3 hours. Next, 6.36 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Thereafter, an aqueous sodium hydroxide solution was added so that the pH became 8.3, and the mixture was heated to 60 ° C. and maintained for 1 hour. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 127 nm by DLS method, a pH of 8.5, a silica concentration of 28.4% by mass, and a water content of 3.5% by mass. There was no sediment, and the mixture showed good dispersibility.

[0240] Synthesis Example 17 Synthesis of PGME Dispersion of Surface-Modified Solid Silica Particles (17) 400 g of PGM-ST-ZL (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in 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 maintained for 3 hours. Next, 6.36 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPEA was added so that the pH was 8.0 to 10.0, and the mixture was heated to 60°C and maintained for 1 hour. The obtained PGME-dispersed solid silica sol using PGME as a dispersion medium had an average particle size of 130 nm and a pH of 6.6 as determined by DLS. There was no sediment and the mixture exhibited good dispersibility.

[0241] Synthesis Example 18 Synthesis of MeOH Dispersion (18) of Solid 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 subjected to hydrothermal treatment at 230±10° C. for 2.5 hours. 100 g of the obtained sol was added with a 5% diluted aqueous sodium sulfate solution and dissolved in SO . ４ The resulting solution was added to a concentration of 20 to 50 ppm, mixed with 30 g of a hydrogen-type strongly acidic cation exchange resin (trade name: Amberlite IR-120B), stirred for 30 minutes, and filtered to obtain 130 g of acidic silica sol (pH 3, silica concentration 23 mass%, average primary particle diameter 28 nm, Na ２ O: 344ppm, SO ４ Concentration: 30 ppm). 130 g of the acidic silica sol obtained above was placed in an evaporator equipped with a 1 L eggplant-shaped flask, and then MeOH was gradually added while distilling off water at 550 Torr, thereby replacing the water as a dispersion medium with MeOH. When the water content of this dispersion became 2.0 mass% or less, the replacement was terminated, and MeOH was added and adjusted to 30 mass parts, and 92 g of the target MeOH-dispersed silica sol (18) was obtained. The obtained methanol-dispersed solid silica sol using methanol as a dispersion medium had an average primary particle size of 28.0 nm, a silica concentration of 30.0 mass%, a water content of 1.5 mass%, a viscosity of 5.4 mPa s, an average particle size by DLS method of 48 nm, and the amount of Na present in the entire silica particles was 0.0%. ２ SiO of silica converted to O ２ 1700 ppm / SiO ２ The amount of sulfate ions present in the silica sol is ４ Converted to SiO ２ 36 ppm / SiO ２ The amount of aluminum present in the entire silica particle was Al ２ O ３ Converted to SiO ２ 470 ppm / SiO ２ It was.

[0242] (Synthesis Example 19) Synthesis of MeOH dispersion (19) of surface-modified solid 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 maintained for 3 hours. Next, 1.97 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 8.4, and the mixture was heated to 60 ° C. and maintained for 1 hour. The obtained methanol-dispersed solid silica sol using methanol as a dispersion medium had an average particle size of 63 nm and a pH of 7.2 by the DLS method. There was no sedimentation and it showed good dispersibility.

[0243] Synthesis Example 20 Synthesis of MeOH-dispersed hollow silica sol (20) 1856 g of HKT-A20-40D (trade name, manufactured by Ningbo Dilato Co., Ltd.) was placed in a 3 L plastic container. ２ O ３ 32.2 g of sodium aluminate diluted to a concentration of 1.0% by mass (calculated as sodium aluminate) was added dropwise over 1 minute, followed by the addition of 643.6 g of pure water. The mixture was stirred for 30 minutes at a rotation speed of 600 rpm using a mechanical stirrer equipped with a glass-type stirring blade. Next, 2442 g of this mixture was placed in an SUS autoclave vessel, heat-treated at 150°C for 5 hours, and cooled to room temperature. 1.51 g of an 8.2% aqueous sulfuric acid solution was added dropwise to 1700 g of the obtained heat-treated water-dispersed silica sol, and the mixture was stirred at room temperature for 1 hour at a stirring speed of 800 rpm to obtain a sulfuric acid-added heat-treated water-dispersed silica sol. Next, the solution 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 a water-dispersed sol of aluminum-containing hollow silica particles (20-1). The physical properties of the obtained water-dispersed sol (20-1) were measured, and the SiO ２ 14.3% by mass, pH 2.5, average particle size by DLS method 54 nm, specific surface area by BET method (C) 149 m ２ / g, the amount of aluminum bound to the particle surface (A) is 1500 ppm, and the amount of aluminum present in the entire silica particle (B) is Al ２ O ３ Converted to SiO ２The mass ratio was 1900 ppm, the (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, particle refractive index 1.26, shell thickness 6.7 nm. The obtained water-dispersed sol (20-1) was then 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 a water-dispersed sol (20-2) of aluminum-containing hollow silica particles. Its physical properties were a silica concentration of 14.0 mass%, pH 2.3, an average particle diameter by DLS method of 54 nm, and a specific surface area (C) by BET method of 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, (A / B ratio) was 0.60, the average primary particle diameter by TEM observation was 43 nm, and the TEM-equivalent specific surface area (D) was 63 m ２ / g, specific surface area ratio (C / D ratio) 1.8, particle refractive index 1.27, shell thickness 6.0 nm. Thereafter, the eggplant-shaped flask containing the obtained water-dispersed sol (20-2) was set in a rotary evaporator, and distillation was carried out while supplying MeOH at a bath temperature of 120 ° C. under a reduced pressure of 580 Torr, and the dispersion medium was replaced with MeOH to obtain the desired sol. The obtained methanol-dispersed hollow silica sol using methanol as the dispersion medium had an average particle size of 72 nm by DLS method, a pH of 3.1, a silica concentration of 20.3% by mass, and a water content of 1.2% by mass. There was no sediment and it showed good dispersibility.

[0244] Synthesis Example 21 Synthesis of MEK Dispersion of Surface-Modified Hollow Silica Particles (21) 50 g of the MeOH-dispersed hollow silica sol (20) obtained in Synthesis Example 20 was placed in 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 the mixture was heated to 60°C and maintained for 3 hours. Then, 0.87 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. DiPA was then added so that the pH was 8.0, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was then placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, replacing the dispersion medium with MEK to obtain the desired sol. The obtained MEK-dispersed hollow silica sol using MEK as a dispersion medium had an average particle size of 66 nm as measured by DLS, a pH of 7.1, a silica concentration of 19.1% by mass, a water content of 0.2% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the sol showed good dispersibility.

[0245] Synthesis Example 22 Synthesis of MEK Dispersion of Surface-Modified Hollow Silica Particles (22) 50 g of the MeOH-dispersed hollow silica sol (20) obtained in Synthesis Example 20 was placed in 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 maintained for 3 hours. Thereafter, 0.79 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Thereafter, DiPA was added so that the pH was 8.0, and the mixture was heated to 60 ° C. and maintained for 1 hour. Thereafter, the eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80 ° C. and under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK to obtain the desired sol. The obtained MEK-dispersed hollow silica sol using MEK as a dispersion medium had an average particle size of 66 nm as measured by DLS, a pH of 7.1, a silica concentration of 12.8% by mass, a water content of 0.1% by mass, and an MeOH content of 0.2% by mass. No sediment was observed, and the sol showed good dispersibility.

[0246] Synthesis Example 23 Synthesis of MEK Dispersion of Surface-Modified Solid Silica Particles (23) 1,000 g of MA-ST-L was placed in 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, heated to 60 ° C., and maintained for 3 hours. DiPA was then added so that the pH was 8.4, and the mixture was heated to 60 ° C. and maintained for 1 hour. The eggplant-shaped flask containing the resulting sol was then placed in a rotary evaporator, and distilled at a bath temperature of 80 ° C. and a reduced pressure of 550 to 350 Torr while feeding MEK. The dispersion medium was replaced with MEK, yielding the desired sol. The resulting MEK-dispersed solid silica sol using MEK as the dispersion medium had an average particle size of 86 nm by DLS, a pH of 7.6, a silica concentration of 38.9% by mass, a water content of less than 0.1% by mass, and a MeOH content of less than 0.1% by mass. No sediment was observed, and good dispersibility was observed.

[0247] Synthesis Example 24 Synthesis of MEK Dispersion of Surface-Modified Solid Silica Particles (24) 1,000 g of MA-ST-L was placed in 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, heated to 60 ° C., and maintained for 3 hours. DiPA was then added so that the pH became 8.4, and the mixture was heated to 60 ° C. and maintained for 1 hour. The eggplant-shaped flask containing the resulting sol was then placed in a rotary evaporator, and distilled at a bath temperature of 80 ° C. and a reduced pressure of 550 to 350 Torr while feeding MEK. The dispersion medium was replaced with MEK, and the target sol was obtained. The obtained MEK-dispersed solid silica sol using MEK as the dispersion medium had an average particle size of 87 nm by DLS method, a pH of 7.8, a silica concentration of 33.4% by mass, a water content of less than 0.1% by mass, and a MeOH content of less than 0.1% by mass. No sediment was observed, and good dispersibility was observed.

[0248] Synthesis Example 25 Synthesis of MEK Dispersion of Surface-Modified Solid Silica Particles (25) 200 g of the MeOH-dispersed silica sol (8) obtained in Synthesis Example (8) was placed in 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, and the mixture was heated to 60°C and maintained for 2 hours. Thereafter, DiEPA was added so that the pH became 7.9, and the mixture was heated to 60°C and maintained for 2 hours. The eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while feeding MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, replacing the dispersion medium with MEK, thereby obtaining the desired MEK-dispersed solid silica sol using MEK as the dispersion medium. The average particle size measured by DLS was 32.7 nm, the pH was 7.4, the silica concentration was 40.7 mass%, the water content was 0.2 mass%, and the MeOH content was 0.4 mass%. No sediment was observed, and good dispersibility was demonstrated.

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

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

[0251] (Synthesis Example 28) Synthesis of MeOH-dispersed silica sol (28) 100 g of PL-3 (trade name, manufactured by Fuso Chemical Co., Ltd.) was placed in a 500 mL eggplant-shaped flask-equipped evaporator, and then MeOH was gradually added while distilling off water at 580 Torr, thereby replacing the water dispersant with MeOH. When the water content of this dispersion became 2.0 mass% or less, the replacement was terminated, MeOH was added, and the silica particle concentration was adjusted to 30 parts by mass, and 100 g of MeOH-dispersed silica sol (a3) ​​was obtained. The obtained methanol-dispersed silica sol using methanol as a dispersant had a silica concentration of 30.0 mass%, an average particle diameter by DLS method of 69.1 nm, and the amount of Na present in the entire silica particles was Na ２ SiO of silica converted to O ２ The ratio of the mass of SiO to the mass of ２ The amount of sulfate ions present in the silica sol is ４ Converted to SiO ２ 0.7 ppm / SiO ２ The amount of aluminum present in the entire silica particle was Al ２ O ３ Converted to SiO ２ The ratio of the mass of SiO to the mass of ２ It was.

[0252] Synthesis Example 29 Synthesis of Polysiloxane (P1) 14.58 g of TEOS (70 mol% in total silane compounds), 3.57 g of MTMS (20 mol% in total silane compounds), 1.98 g of PTMS (10 mol% in total silane compounds), and 31 g of acetone were placed in a 200 ml flask, and while the mixed solution was stirred with a magnetic stirrer, 6.67 g of 0.01 mol / L hydrochloric acid was added dropwise thereto. After the addition, the flask was transferred to an oil bath adjusted to 85 ° C., and the reaction was allowed to proceed under reflux for 240 minutes. Thereafter, the reaction solution was cooled to room temperature, and 40 g of PGMEA was added to the reaction solution. The reaction by-products, methanol, ethanol, water, and hydrochloric acid, were removed by distillation under reduced pressure, and the mixture was concentrated to obtain a PGMEA solution of a hydrolysis condensate (polymer, formula d-1) having the following unit structure: PGEE was added to the mixture, and solvent substitution was carried out by distillation to obtain a PGEE polymer solution. The resulting solution was adjusted with PGEE to a concentration of 15% by mass in terms of solid residue at 200°C. The weight-average molecular weight (Mw) of the resulting polymer was 1,500 in terms of polystyrene.

[0253] Synthesis Example 30 Preparation of Polyamic Acid (P2) 4,4'-Diaminodiphenyl ether (DDE), pyromellitic dianhydride (PMDA), and NMP and DMAC as solvents were polymerized at a temperature of 50°C with stirring to obtain a polyamic acid (solid content 17% by mass, viscosity at 25°C measured with an E-type viscometer of 13,640 mPa s) corresponding to formula (e-1). The polyamic acid was polymerized using an equimolar ratio of 1:1 between the DDE and PMDA. The weight-average molecular weight of the obtained polyamic acid was 63,000. In formula (e-1), n ​​is the number of repeating units.

[0254] Synthesis Example 31 Synthesis of Polyimide (P3) 25.6 g (0.08 mol) of 2,2'-bis(trifluoromethyl)benzidine was placed in a 250 mL three-necked reaction flask equipped with a nitrogen inlet / outlet, a mechanical stirrer, and a condenser. Then, 173 g of GBL was added, and stirring was initiated. Immediately after the diamine was completely dissolved in the solvent, 10.0 g (4 mmol) of 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 with stirring, and the mixture was heated to 140°C under nitrogen. 0.35 g of 1-ethylpiperidine was then added to the solution, and the mixture was heated to 180°C for 7 hours under nitrogen. Finally, heating was stopped, and the reaction solution was diluted to 10% by weight, and stirring was continued overnight. The resulting polyimide reaction solution was added to 2000 g of a 50% by weight GBL:MeOH mixed solution and stirred for 30 minutes. The resulting polyimide solid was then filtered to obtain a purified polyimide. The resulting polyimide solid was then stirred in 2000 g of MeOH for 30 minutes, and the resulting polyimide solid was filtered. This purification procedure of stirring and filtering the polyimide solid was repeated three times. The MeOH residue in the polyimide was removed by drying in a vacuum oven at 150°C for 8 hours, finally yielding 21.5 g of dried polyimide (P3). The resulting polyimide contained 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).

[0255] (Synthesis Example 32) Synthesis of MeOH dispersion of surface-modified solid silica particles (32) 300 g of MT-ST (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 maintained for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 8.6, and the mixture was heated to 60 ° C. and maintained for 1 hour. The obtained MeOH-dispersed solid silica sol using MeOH as a dispersion medium had an average particle size of 22 nm by DLS method, a pH of 8.2, a silica concentration of 25.0% by mass, and a water content of 2.2% by mass. There was no sediment and the mixture showed good dispersibility.

[0256] Synthesis Example 33 Synthesis of MEK Dispersion of Surface-Modified Solid Silica Particles (33) 300 g of MT-ST (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in 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 maintained for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 8.2, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was set in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the target sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 19 nm as measured by DLS, a pH of 7.6, a silica concentration of 30.8% by mass, a water content of 0.2% by mass, and an MeOH content of 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0257] Synthesis Example 34 Synthesis of MEK Dispersion (34) of Surface-Modified Solid Silica Particles 300 g of MT-ST (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in 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 maintained for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 7.9, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was set in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the target sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 20 nm as measured by DLS, a pH of 7.3, a silica concentration of 31.0% by mass, a water content of 0.2% by mass, and an MeOH content of 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0258] Synthesis Example 35 Synthesis of MEK Dispersion (35) of Surface-Modified Solid Silica Particles 200 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was placed in 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 maintained for 3 hours. Next, 13.39 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 7.7, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the target sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 33 nm as measured by DLS, a pH of 7.1, a silica concentration of 39.9% by mass, a water content of 0.2% by mass, and an MeOH content of 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0259] Synthesis Example 36 Synthesis of MEK Dispersion (36) of Surface-Modified Solid Silica Particles 200 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was placed in 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, and the mixture was heated to 60°C and maintained for 3 hours. Next, 13.39 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 7.7, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the target sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 33 nm as measured by DLS, a pH of 7.1, a silica concentration of 39.9% by mass, a water content of 0.2% by mass, and an MeOH content of 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0260] Synthesis Example 37 Synthesis of MEK Dispersion (37) of Surface-Modified Solid Silica Particles 300 g of the MeOH dispersion (8) obtained in Synthesis Example 8 was placed in 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, and the mixture was heated to 60°C and maintained for 3 hours. Next, 19.77 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. Thereafter, DiPEA was added so that the pH became 7.8, and the mixture was heated to 60°C and maintained for 1 hour. The eggplant-shaped flask containing the obtained sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C under a reduced pressure of 550 to 350 Torr, and the dispersion medium was replaced with MEK, thereby obtaining the desired sol. The obtained MEK-dispersed solid silica sol using MEK as a dispersion medium had an average particle size of 29 nm as measured by DLS, a pH of 7.2, a silica concentration of 40.7% by mass, a water content of 0.1% by mass, and an MeOH content of less than 0.1% by mass. No sediment was observed, and the solid silica sol showed good dispersibility.

[0261] Synthesis Example 38 Synthesis of MEK-dispersed hollow silica sol (38) Aluminum atom-containing hollow silica particles (average primary particle diameter of 71 nm by TEM observation, BET specific surface area (D) of 102 m) were prepared in the same manner as in Synthesis Example 20, except that HKT-A20-70D was used instead of HKT-A20-40D in Synthesis Example 20. ２ / g) MeOH-dispersed silica sol was obtained. 50 g of the obtained MeOH-dispersed silica sol of aluminum atom-containing hollow silica particles was placed in a 100 mL plastic container, 50 ml of cation exchange resin (Dow Chemical Company, trade name: Amberlite IR-120B) was added, and the mixture was maintained for 60 minutes while stirring at 100 rpm with a mix rotor (AS ONE Corporation, trade name: MIX-ROTAR MR-5). A MeOH-dispersed silica sol of hollow silica particles was obtained. Next, 25 g of the obtained MeOH-dispersed silica sol of hollow silica particles was placed in a 50 mL recovery 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 the mixture was heated to 60 ° C. and maintained for 3 hours. Next, 0.29 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. DiPA was then added to adjust the pH to 8.0-10.0, and the mixture was heated to 60°C and maintained at this temperature for 1 hour, yielding a silica sol of surface-modified hollow silica particles dispersed in MeOH. The eggplant-shaped flask containing the resulting silica sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C and a reduced pressure of 550-350 Torr. The dispersion medium was replaced from MeOH to MEK, yielding a MEK-dispersed silica sol of hollow silica particles. The resulting MEK-dispersed silica sol had an average primary particle diameter of 71 nm measured by TEM, an average particle diameter of 105 nm measured by DLS, a pH of 6.2, a solids (silica particle) concentration of 30.1% by mass, a water content of 0.3% by mass, and MeOH of less than 0.1% by mass. The resulting hollow silica sol exhibited no sediment and good dispersibility.

[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 placed in a 250 mL plastic container, 10 ml of cation exchange resin (Dow Chemical Company, trade name: Amberlite IR-120B) was added, and the mixture was stirred at 100 rpm with a mix rotor (AS ONE Corporation, trade name: MIX-ROTAR MR-5) for 60 minutes to obtain a MeOH-dispersed silica sol of hollow silica particles. Next, 55 g of the obtained MeOH-dispersed silica sol of hollow silica particles was placed in a 300 mL eggplant flask, and while stirring with a magnetic stirrer, 0.01 g of MEHQ and 0.50 g of APMDMS were added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Next, 1.29 g of TMSO was added, and the mixture was heated to 60 ° C. and maintained for 3 hours. Next, DiPA was added to adjust the pH to 8.0, and the mixture was heated to 60°C and maintained at this temperature for 1 hour to obtain a silica sol of surface-modified hollow silica particles dispersed in MeOH. The eggplant-shaped flask containing the obtained silica sol was placed in a rotary evaporator, and distillation was carried out while supplying MEK at a bath temperature of 80°C and a reduced pressure of 550 to 350 Torr. The dispersion medium was replaced from MeOH to MEK, yielding a MEK-dispersed silica sol of hollow silica particles. The obtained MEK-dispersed silica sol had an average primary particle diameter of 40 nm measured by TEM, an average particle diameter of 62 nm measured by DLS, a pH of 7.4, a viscosity of 1.4 mPa·s, a solids (silica particle) concentration of 21.6% by mass, a water content of 0.4% by mass, and MeOH of less than 0.1% by mass. The obtained hollow silica sol showed no sediment and exhibited good dispersibility.

[0263] Synthesis Example 40 Synthesis of MeOH Dispersion of Surface-Modified Solid Silica Particles (40) 300 g of MT-ST (trade name, manufactured by Nissan Chemical Industries, Ltd.) was placed in 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 maintained for 3 hours. Next, 29.03 g of TMSO was added, and the mixture was heated to 60°C and maintained for 3 hours. The obtained MeOH-dispersed solid silica sol using MeOH as a dispersion medium had an average particle size of 21 nm by DLS method, a silica concentration of 25.1% by mass, and a water content of 2.1% by mass. There was no sediment, and the mixture showed good dispersibility.

[0264] (Synthesis Example 41) Synthesis of MeOH dispersion (41) of surface-modified solid silica particles 50 g of 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 maintained for 3 hours. The obtained MeOH-dispersed hollow silica sol using methanol as a dispersion medium had an average particle size of 73 nm by DLS method, a pH of 3.3, a silica concentration of 17.2% by mass, and a water content of 1.0% by mass. There was no sediment, and it showed good dispersibility.

[0265] Synthesis Example 42 Synthesis of MEK-dispersed hollow silica sol (42) An 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 measured by TEM, an average particle diameter of 109 nm measured by DLS, a pH of 6.5, a solids (silica particles) concentration of 30.3 mass%, a water content of 0.4 mass%, and MeOH of less than 0.1 mass%. The obtained hollow silica sol was free of sediment and showed good dispersibility.

[0266] (Evaluation of High-Concentration Sol Preparation by Redispersion of Dried Powder) Example 1-1: A 100 ml eggplant-shaped flask containing 50 g of the sol obtained in Synthesis Example 1 was placed in a rotary evaporator, and the dispersion solvent was removed under reduced pressure of 20 to 50 Torr at a bath temperature of 60 to 80°C, to obtain a dried sol. The dried product was then crushed with a mortar and pestle to obtain a silica particle powder. Subsequently, 1.20 g of the obtained silica particle powder was placed in a 13 ml glass vial, and an organic solvent listed in Tables 1 to 6 was added so that the concentration of metal oxides with a refractive index of 1.4 to 3.0 was 60% by mass or more, or the concentration of metal oxides with a refractive index of 1.1 to less than 1.4 was 30% by mass or more. The mixture was then stirred for 12 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). If the appearance of the resulting mixture was transparent, it was deemed redispersible; if the appearance was opaque (cloudy due to aggregation), had no fluidity, or powder remained, it was deemed unredispersible. Furthermore, the DLS after redispersion of the redispersible silica particle powder was obtained. The results are listed in the table as "OK" if redispersible, "NG" if unredispersible, and "-" if not. Furthermore, from the DLS measurement results after redispersion, the DLS ratio before and after redispersion was recorded: (average particle size measured by the DLS method in the high-concentration sol) / (average particle size measured by the DLS method of the silica particles before removing the organic solvent). Examples 1-2 to 1-22, Examples 1-25 to 1-30, and Examples 1-33 to 1-35: Dried powders of the sols obtained in Synthesis Examples 2 to 19 and Synthesis Examples 32 to 37 were prepared in the same manner as in Example 1-1, and mixed with the organic solvents listed in Tables 1 to 6 to confirm redispersibility. The obtained redispersibility results and the DLS measurement results after redispersion are listed in Tables 1 to 6. Examples 1-23 to 1-24, Examples 1-31, 1-32, 1-36: Dry powders of the sols obtained in Synthesis Examples 21 to 22, 38 to 39, and 42 were prepared in the same manner as in Example 1, except that the organic solvents listed in Table 1 were added so that the solid content in Example 1-1 was 30% by mass or more. These were mixed with the organic solvents listed in Tables 1 to 6, and redispersibility was confirmed. The obtained redispersibility results and the DLS measurement results after redispersion are shown in Tables 1 to 6.Comparative Examples 1-1 to 1-7: Dry powders of the sols obtained in Synthesis Examples 23 to 27, 40, and 41 were prepared in the same manner as in Example 1-1, and mixed with the organic solvents listed in Tables 1 to 6 to confirm redispersibility. The redispersibility results obtained and the DLS measurement results after redispersion are listed in Tables 1 to 6. A representative example showing the appearance of the sol after checking whether redispersibility was possible is shown in Figure 4. In Figure 4, the left side shows Example 1-3, which was redispersible, and the right side shows Comparative Example 1-2, which was not redispersible.

[0267]

[0268]

[0269]

[0270]

[0271]

[0272]

[0273] From the above results, Examples 1-1 to 1-36, which were surface-coated with a hydrolyzate of a silane compound (A) having two chemical groups (a1) and two hydrolyzable groups (a2), contained a basic compound (I), and had a hydrophobicity of 30% by volume or more, exhibited high redispersibility in organic solvents and high-concentration properties. On the other hand, Comparative Examples 1-1 to 1-4, which were coated with a hydrolyzate of a silane compound (A) having two organic functional chemical groups (a1) and two hydrolyzable groups (a2), contained a basic compound (I), and had a hydrophobicity of less than 40% by volume, did not exhibit redispersibility in organic solvents or high-concentration properties. Comparative Example 1-5, which was not coated with a hydrolyzate of a silane compound (A) having two organic functional groups (a1) and two hydrolyzable groups (a2), did not contain a basic compound (I), and had a hydrophobicity of less than 40% by volume, did not exhibit redispersibility in organic solvents and did not exhibit high-concentration properties.Alternatively, Comparative Examples 1-6 and 1-7, which were coated with a hydrolyzate of a silane compound (A) having two organic functional groups (a1) and two hydrolyzable groups (a2) and did not contain a basic compound (I), did not exhibit redispersibility in organic solvents and did not exhibit high-concentration properties.

[0274] (Evaluation of High-Concentration Sol Production by Solvent Replacement or Concentration) Example 2-1: A 50 ml eggplant-shaped flask containing 20 g of the sol obtained in Synthesis Example 3 was placed in a rotary evaporator, and MEK was distilled off at a bath temperature of 80°C and a reduced pressure of 400 Torr, yielding a high-concentration sol with a metal oxide concentration of 60% by mass. The resulting high-concentration sol exhibited good dispersibility and no sediment. The results are shown in Tables 7 and 8. Based on the DLS measurement results after concentration, the DLS ratio before and after concentration was recorded: (average particle size measured by the DLS method in the high-concentration sol) / (average particle size measured by the DLS method of the silica particles before removing the organic solvent). Example 2-2: A 50 ml eggplant-shaped flask containing 20 g of the sol obtained in Synthesis Example 21 was placed in a rotary evaporator, and MEK was distilled off while supplying PGMEA at a bath temperature of 80°C and a reduced pressure of 400 Torr. By concentrating while replacing the dispersion medium with PGMEA, a sol with a silica concentration of 40% by mass or more was obtained. The obtained sol was free of sediment and showed good dispersibility. The results are shown in Tables 7 and 8. From the DLS measurement results after concentration, the DLS ratio before and after concentration was recorded: (average particle size in the high-concentration sol as measured by the DLS method) / (average particle size of the silica particles as measured by the DLS method before removing the organic solvent). In Table 8, OK indicates that redispersion was possible, and NG indicates that redispersion was not possible.

[0275]

[0276]

[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, and the storage stability at 50°C was confirmed. After 4 weeks at 50°C, the average particle diameter measured by DLS was 86 nm, confirming high storage stability. The results are shown in Tables 9 and 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. After 4 weeks at 50°C, the average particle diameter measured by DLS was 78 nm, confirming high storage stability. The results are shown in Tables 9 and 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. After 4 weeks at 50°C, the average particle diameter measured by DLS was 71 nm, confirming high storage stability. The results obtained are shown in Tables 9 and 10.

[0278]

[0279]

[0280] (Particle Surface Condition, Redispersibility, and Concentration-Enhancing Properties 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 settling tube (manufactured by Thermo Fisher Scientifics, trade name: Nalgene Oak Ridge), and 8 ml of MEK and 20 ml of hexane were added to cause cloudiness due to aggregation, separation, or precipitation. The mixture was then centrifuged (temperature: 5°C, rotation speed: 5000 rpm, time: 30 minutes) using a centrifuge (manufactured by Tomy Seiko Co., Ltd., trade name: High-Speed ​​Refrigerated Centrifuge Suprema 21), and the supernatant was removed. 4 ml of acetone was then added, and the precipitate obtained by centrifugation was redissolved using a test tube mixer (As One Corporation, trade name: MVM-10), followed by the addition of 20 mL of hexane. The mixture was then centrifuged, and the supernatant was removed. Thereafter, 4 ml of acetone was added, and the precipitate formed by centrifugation was redissolved in a test tube mixer, followed by the addition of 20 ml of hexane. The mixture was then centrifuged and the supernatant was removed. The resulting mixture was vacuum dried (temperature: 60°C, -0.1 MPa gauge pressure on the Bourdon tube vacuum gauge scale: 0.1013 MPa - 0.1 MPa = 1.3 kPa in terms of absolute pressure (atmospheric pressure + gauge pressure)), and the resulting powder was pulverized in a mortar to obtain silica particles. The elemental analysis results of the obtained silica particles, and ２９ The results of the Si-NMR measurement are shown in Tables 11 and 12. ２９In the Si-NMR structural analysis, (A) showed an integral value ratio of 90 to 100 mol%, (B) showed an integral value ratio of 60 to less than 90 mol%, (C) showed an integral value ratio of 30 to less than 60 mol%, (D) showed an integral value ratio of 0.1 to less than 30 mol%, and (E) showed no integral value ratio (no detected signal). Furthermore, the redispersibility and concentration-enhancing properties of the obtained silica particles were evaluated. To evaluate redispersibility and concentration-enhancing properties, 1.20 g of the obtained silica particle powder was placed in a 13 ml glass vial, and PGMEA was added so that the metal oxide concentration was 60 mass% or more. The mixture was then stirred for 12 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). If the appearance of the resulting mixture was transparent, it was deemed redispersible; if the appearance was opaque or powder remained, it was deemed unredispersible. The results were recorded in the table as "OK" if the silica particles were redispersible, and "NG" if they were not redispersible. Examples 4-2 to 4-6: Silica particle powders of Synthesis Examples 3, 4, 6, 9, and 11 were prepared using the same method as in Example 4-1. Furthermore, the surface condition, redispersibility, and concentration-enhancing properties of the obtained silica particles were confirmed using the same method as in Example 4-1. The results are shown in Tables 11 to 12. Comparative Examples 4-1 to 4-3: Silica particle powders of Synthesis Examples 23, 24, and 27 were prepared using the same method as in Example 4-1. Furthermore, the surface condition, redispersibility, and concentration-enhancing properties of the obtained silica particles were confirmed using the same method as in Example 4-1, except that instead of adding PGMEA to achieve a solids content of 60% by mass or more in Example 4-1, PGMEA was added to achieve a metal oxide concentration of 41% by mass or more. The results are shown in Tables 11 to 12.

[0281]

[0282]

[0283] From the above results, it is clear that the silane compounds on the surface of metal oxide particles ２９In the Si-NMR measurement, the content ratios of the M structure, the D structure, and the T structure, when the total of the M structure, the D structure, and the T structure is taken as 100 mol%, are 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%, and Examples 4-1 to 4-7 showed high redispersibility in organic solvents and high concentration properties. ２９ In the Si-NMR measurement, when the content ratio of each of the M structure, the D structure, and the T structure was 100 mol % as the sum of the M structure, the D structure, and the T structure, Comparative Example 4-1, in which the D structure was 90 mol % or more and no M structure was present, Comparative Example 4-2, in which the M structure was 90 mol % or more and no D structure was present, and Comparative Example 4-3, in which no structure selected from the M structure, the D structure, and the T structure was present, did not exhibit redispersibility in organic solvents and did not exhibit concentration-enhancing properties.

[0284] (Polysiloxane Composition Evaluation) Example 5-1: A recovery flask containing a solution prepared by mixing the polymer of Synthesis Example 29 and the silica sol obtained in Synthesis Example 21 in a 50:50 solids ratio was placed in an evaporator, and MeOH was distilled off at a bath temperature of 80°C and 250 Torr to prepare the target compositions listed in Tables 13 and 14. After measuring the concentration, the solution was applied to a 5 x 5 cm alkali-free glass substrate (manufactured by Corning Incorporated, product name: Eagle XG) set on a spin coater (manufactured by Mikasa Co., Ltd., product name: MS-A100) under film-forming conditions of 800 rpm x 5 seconds. The resulting film was then baked on a hot plate at 100°C for 2 minutes and then further baked at 180°C for 30 minutes to obtain a coating film. The resulting coating film was transparent, and the total light transmittance (T.T.) was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name: NHD-5000), resulting in a value of 93.3%. The film thickness was measured using a product name F20-EXR (manufactured by FILMETRICS Co., Ltd.) and was found to be 1.603 μm. The conditions and results obtained are shown in Tables 13 and 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 firing had cracks, and the desired coating film was not obtained. The conditions and results obtained are shown in Tables 13 and 14. A photograph of the film obtained in Comparative Example 5-1 is shown in Figure 2. The film formability was evaluated according to the following criteria (A), (B), and (C). The results are shown in Table 13. (A): A film of 1.5 μm or more could be formed, (B): A film of more than 1 μm but less than 1.5 μm could be formed, and (C): A film of 1 μm or less could not be formed.

[0285]

[0286]

[0287] From the above results, silica particles that were surface-coated with a hydrolyzate of MPDMS as the silane compound (A) having two organic functional chemical groups (a1) and two hydrolyzable groups (a2), contained DiPA as the basic compound (I), and showed a hydrophobicity of 30% or more, showed high compatibility with resins, and a coating film was obtained. On the other hand, measurements by the leaching method showed that Al was not formed on the surface of metal oxide particles. ２ O ３When metal oxide particles were used in which the aluminum atoms were not contained in the ratio (A) of 100 to 20,000 ppm / metal oxide relative to the mass of the metal oxide, the desired coating film could not be obtained.

[0288] (Evaluation of Maleimide Resin Composition) Example 6-1: The compatibility of the surface-modified silica particles obtained in Synthesis Example 1-3 with 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 placed in a 300 mL eggplant-shaped flask, and 20 g of a low-viscosity liquid maleimide resin (maleimide-terminated polyimide resin, manufactured by DMI Corporation, product name: BMI-689, 1000 to 2000 mPa s (25°C)) was added while stirring with a magnetic stirrer. The eggplant-shaped flask containing the resulting mixture of the MEK dispersion of surface-modified silica particles and maleimide resin was then placed in a rotary evaporator, and distillation was performed at a bath temperature of 80°C under reduced pressure of 400 to 30 Torr. The dispersion medium was replaced from MEK with the maleimide resin, thereby obtaining a maleimide resin dispersion of surface-modified silica particles. The resulting maleimide resin dispersion of 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 to 7000 mPa s (B-type viscometer, temperature 25°C), an average dispersed particle diameter of 79 nm as determined by DLS, and a yellow, transparent appearance. Furthermore, the resulting maleimide resin dispersion of surface-modified silica particles showed no change in appearance and no precipitate was formed even after being left to stand at room temperature for one week. The resulting maleimide resin dispersion of surface-modified silica particles was then applied to a glass substrate degreased with acetone using a hand-applied bar coater (gap: 25 μm). The substrate was then baked for 30 minutes on a hot plate heated to 100°C under a nitrogen atmosphere. The temperature of the hot plate was then further increased to 230°C, and the substrate was then baked for 120 minutes, yielding a cured film of a composite material containing surface-modified silica particles and maleimide resin (see FIG. 3(B)). The resulting cured film was yellow and transparent, and no repellency was observed with the glass substrate (for reference, in FIG. 1, the areas where the resin dispersion and the low-viscosity liquid maleimide resin described below were applied are indicated by black frames). The film thickness was measured using a constant-pressure thickness gauge (manufactured by Teclock Corporation, model: PG-01A) and was found to be 19 μm.On the other hand, as an example in which surface-modified silica particles were not used, the above-mentioned low-viscosity liquid maleimide resin (trade name: BMI-689) alone was used, and this was applied to a glass substrate that had been degreased with acetone using a hand-applied bar coater (gap: 25 μm). The coating was then baked for 30 minutes on a hot plate heated to 100°C under a nitrogen atmosphere, and the temperature of the hot plate was further increased to 230°C, after which the coating was baked for 120 minutes, thereby obtaining a cured film of only the maleimide resin (see FIG. 3(A)). The obtained cured film was yellow and transparent, but repelling from the glass substrate was observed.

[0289] (Polyimide Resin Composition Evaluation Part 1) Example 7-1: The dried silica powder obtained in Example 1-3 was redispersed in DMAC to a silica concentration of 30% by mass. The obtained DMAC redispersion sol was added to the polyamic acid obtained in Synthesis Example 30 in a resin / SiO 2 mass ratio. ２ The mixture was mixed in a glass bottle to a ratio of 80 / 20. The mixture was then degassed and stirred for 20 minutes using a vacuum degasser (EME Corporation, trade name: V-mini300) to obtain a silica-blended polyamic acid. The resulting silica-blended polyamic acid was then applied to a Cu plate (AS ONE Corporation, trade name: HC0536, 300 mm x 300 mm, 0.5 mm thick) using an applicator (BEVS Corporation, trade name: Film Applicator with Film Thickness Adjustment Function B / M150 mm). The solvent was removed and the plate was thermally cured at 70°C for 30 minutes, 100°C for 30 minutes, 150°C for 30 minutes, and 290°C for 60 minutes to obtain a Cu plate (coating thickness: 29-32 μm) with a baked silica-blended polyimide. This was then cut into 5 cm squares to serve as insulation test samples.

[0290] (Measurement of dielectric breakdown life) A plate-shaped sample measuring 50 mm x 50 mm and 0.5 mm thick was measured for dielectric 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 a dielectric breakdown tester manufactured by Yamayo Testing Instruments, Model: YST-243WS. The electrodes used were a flat electrode (φ = 25 mm) at the bottom and a spherical electrode (φ = 20 mm) at the top, with both electrodes being placed so as to be in contact with the sample. Three to four measurements were performed at an applied voltage of 2.0 kV, and the average value was calculated. The dielectric breakdown life of the sample containing Examples 1-3 was 196 minutes. A sample containing only polyimide resin without silica was also measured as a blank. The dielectric breakdown life of the sample containing only polyimide resin was 21 minutes.

[0291] (Polyimide Resin Composition Evaluation 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 Example 1-23 was redispersed in 40% by mass DMAC to obtain a redispersion. PI-A was then added to this redispersion so that the polyimide:dry powder weight ratio was 1:1, and the mixture was stirred at 1500 rpm for 10 minutes in a vacuum defoamer (manufactured by EME, trade name V-mini300) to obtain the target polyimide / silica dispersion. This polyimide / silica dispersion was applied to an Eagle XG plate using a bar coater to a thickness of 25 μm. The mixture was then baked on a hot plate under a nitrogen atmosphere at 90°C for 1 hour and then 230°C for 1 hour to obtain a polyimide-silica coating film. The resulting film exhibited self-supporting properties.

[0292] (Silica sol dispersed in epoxy monomer) Example 8-1: The compatibility of the surface-modified silica particles obtained in Synthesis Example 3 with 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 placed in a 300 mL eggplant-shaped flask, and 20 g of an epoxy resin (Nippon Steel Chemical & Material Co., Ltd., bisphenol A-type epoxy resin, product name: YD-8125, 3900 to 5300 mPa s) was added while stirring with a magnetic stirrer. The eggplant-shaped flask containing the resulting mixture of the MEK dispersion of the surface-modified silica particles and the epoxy resin was then placed in a rotary evaporator, and distillation was performed at a bath temperature of 80°C under reduced pressure of 400 to 30 Torr. The dispersion medium was replaced from MEK with the epoxy resin, thereby obtaining an epoxy resin dispersion of surface-modified silica particles. The obtained epoxy resin dispersion of 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 14,000 to 16,000 mPa s (B-type viscometer, temperature 25°C), an average dispersed particle size of 79 nm by DLS method, and an epoxy equivalent of 264 g / eq (in accordance with JIS K7236), and was white and transparent in appearance. Furthermore, the obtained epoxy resin dispersion of surface-modified silica particles showed no change in appearance and no precipitate was formed even after being left to stand at room temperature for one week.

[0293] (Settling and Recovery of Surface-Modified Silica Particles) Example 9-1: 50 g of the MeOH dispersion (32) of surface-modified solid silica particles obtained in Synthesis Example 32 was placed in a 200 ml beaker, and 50 g of pure water was added. After leaving the mixture to stand for 30 minutes, the surface-modified solid silica particles settled, and the supernatant was removed by decantation to recover hydrous surface-modified solid silica particles. The beaker containing the obtained hydrous surface-modified solid silica particles was placed in a vacuum dryer (temperature: 60 to 100°C, pressure: -0.1 MPa gauge pressure on a Bourdon tube vacuum gauge; 0.1013 MPa - 0.1 MPa = 1.3 kPa in terms of absolute pressure (atmospheric pressure + gauge pressure)) and maintained therein until the moisture content of the hydrous surface-modified solid silica particles reached 1.0 mass% or less per silica particle. Next, 5.0 g of the obtained water-reduced surface-modified solid silica particles were placed in a 50 ml glass vial, and 18.5 g of MeOH was added. The mixture was then stirred for 2 hours using a mix rotor (manufactured by AS ONE Corporation, trade name: MIX-ROTAR MR-5), resulting in a redispersed MeOH dispersion of surface-modified solid silica particles redispersed in MeOH. The obtained redispersed MeOH-dispersed solid silica sol using MeOH as the redispersion medium had an average particle size of 21 nm as measured by DLS, a pH of 7.4, a silica concentration of 21.1% by mass, and a viscosity of 2.1 mPa s. Furthermore, filtration using a nylon syringe filter (trade name, hole diameter 0.45 μm, manufactured by Membrane Solutions) showed no clogging and demonstrated 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 placed in a rotary evaporator, and the dispersion solvent was removed at a bath temperature of 80°C under a reduced pressure of 50 Torr, thereby obtaining a dried sol. The obtained dried product was then crushed with a mortar and pestle to obtain a silica particle powder. Thereafter, 1.4 g of the obtained silica particle powder was placed in a 13 ml glass vial and mixed with the redispersion medium in the combination and concentration shown in Tables 15 and 16. The mixture was stirred for 12 hours using a mix rotor (manufactured by AS ONE Corporation, product name: MIX-ROTAR MR-5). If the obtained redispersed sol had fluidity, it was rated as redispersible; if it did not have fluidity, it was rated as unredispersible. Furthermore, the viscosity of the redispersible sols that were redispersible was measured using an EMS viscometer. The results are shown in Tables 15 and 16 as "OK" when redispersible, "NG" when redispersible, and "-" when not performed. Furthermore, the viscosity ratio of the redispersed sol to the dispersion medium: (viscosity of the redispersed sol) / (viscosity of the dispersion medium) was shown from the DLS measurement results after redispersion.

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

[0296]

[0297]

[0298] (Evaluation of fluidity of two particle mixed sols with different average primary particle diameters) Example 11-1: 0.1 g of a PGMEA dispersion sol (solid content 30 mass %, EMS viscosity 3 mPa s) of metal oxide particles having an average primary particle diameter of 12 nm obtained in Example 10-5 and 0.9 g of a PGMEA dispersion sol (solid content 30 mass %, EMS viscosity 1650 mPa s) of metal oxide particles having an average primary particle diameter of 71 nm obtained in Example 10-13 were placed in 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 PGMEA sol of a mixture of two particles having different average primary particle sizes had a solid content of 30% by mass, an EMS viscosity of 449 mPa s, a viscosity ratio (sol / dispersion medium) of 397, contained metal oxide particles having average primary particle sizes of 12 nm and 71 nm, had the largest peak a in the range of D50 to D90 in the range of 35 nm or more and 200 nm or less, and had the largest peak b in the range of D10 to D50 in the range of 5 nm or more and less than 100 nm, and had a ratio of (volume of metal oxide particles having an average primary particle size of 71 nm) / (volume of metal oxide particles having an average primary particle size of 12 nm) of 21, and had a viscosity that was more than half that of the PGMEA-dispersed sol of metal oxide particles having an average primary particle size of 71 nm obtained in Examples 10-13, thereby improving fluidity.

[0299] Example 11-2: 0.1 g of a PGMEA dispersion sol (solid content 60 mass %, EMS viscosity 51 mPa s) of metal oxide particles having an average primary particle size of 12 nm obtained in Example 10-5 and 0.9 g of a PGMEA dispersion sol (solid content 60 mass %, EMS viscosity 3150 mPa s) of metal oxide particles having an average primary particle size of 80 nm obtained in Example 10-14 were placed in 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 PGMEA sol of a mixture of two particles having different average primary particle sizes had a solids content of 60 mass%, a metal oxide particle volume ratio (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, and contained metal oxide particles having average primary particle sizes of 12 nm and 80 nm, with the largest peak a in the range of D50 to D90 existing 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 existing in the range of 5 nm or more and less than 100 nm. Compared with the PGMEA-dispersed sol of metal oxide particles having an average primary particle size of 80 nm obtained in Example 10-14, the viscosity was reduced by more than half, and fluidity was improved.

[0300] Example 11-3: 0.18 g of the dry powder of metal oxide particles having an average primary particle size of 12 nm obtained in Example 10-5, 1.62 g of the dry powder of metal oxide particles having an average primary particle size of 80 nm obtained in Example 10-14, and 1.2 g of PGMEA were placed in 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 obtained PGMEA sol of a mixture of two particles having different average primary particle sizes had a solids content of 60 mass%, a metal oxide particle volume ratio (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, and contained metal oxide particles having average primary particle sizes of 12 nm and 80 nm, with the largest peak a in the range of D50 to D90 existing 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 existing in the range of 5 nm or more and less than 100 nm. The viscosity was reduced by more than half compared to the PGMEA-dispersed sol of metal oxide particles having an average primary particle size of 80 nm obtained in Example 10-14, and fluidity was improved.

[0301] Example 11-4: 0.1 g of a PGMEA dispersion sol (solid content 30 mass%, EMS viscosity 5 mPa s) of metal oxide particles having an average primary particle size of 43 nm obtained in Example 10-12 and 0.9 g of a PGMEA dispersion sol (solid content 30 mass%, EMS viscosity 27 mPa s) of metal oxide particles having an average primary particle size of 71 nm obtained in Example 10-15 were placed in 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 PGMEA sol of two particles having different average primary particle sizes had a solids content of 30 mass%, an EMS viscosity of 16 mPa·s, a viscosity ratio (sol / dispersion medium) of 14, contained metal oxide particles having average primary particle sizes of 43 nm and 71 nm, had the largest peak a in the range of D50 to D90 in the range of 35 nm or more and 200 nm or less, and had the largest peak b in the range of D10 to D50 in the range of 5 nm or more and less than 100 nm, and had a ratio of (volume of metal oxide particles having an average primary particle size of 71 nm) / (volume of metal oxide particles having an average primary particle size of 43 nm) of 13, and had a viscosity lower by 10 mPa·s or more than that of the PGMEA-dispersed sol of metal oxide particles having an average primary particle size of 71 nm obtained in Examples 10-15, thereby improving fluidity.

[0302] The present invention provides metal oxide particles that can be concentrated to a high concentration in an organic solvent that is a dispersion medium for a metal oxide sol and that 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), the metal oxide particles containing a basic compound (I) and having a hydrophobicity of 30 to 80 volume % as measured by a methanol titration method, the metal oxide particles having a particle refractive index of 1.4 to 3.0 and being dispersible in an organic solvent at a metal oxide concentration of 40 mass % or more, or the metal oxide particles having a particle refractive index of 1.1 to less than 1.4 and being dispersible in an organic solvent at a metal oxide concentration of 25 mass % or more.

2. 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 at least one metal component selected from the group consisting of silicon, metal elements in the 4th period of the periodic table, and metal elements in the 5th period of the periodic table.

3. 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 comprises 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. The silane compound (A) is represented by the following formula (1): (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 which is bonded to a silicon atom by a Si-C bond; R ２ and each of the hydrolyzable groups (a2) 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.

5. A silane compound (B) represented by the following formula (2) and the following formula (3): (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 are hydrolyzable groups (b2), each of which is R ５ 2. The metal oxide particles according to claim 1 , which are surface-coated with a hydrolysate of at least one silane compound selected from the group of silane compounds represented by the following formula:

6. A silane compound (C) represented by the following formula (4): (In formula (4), R ６ is a chemical group (c1) 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 an alkyl group containing a (meth)acryloxy group, and which 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 atom.

7. 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 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 %.

8. 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.

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

10. A metal oxide sol in which the metal oxide particles according to any one of claims 1 to 9 are dispersed in an organic solvent and / or a reactive monomer.

11. The metal oxide sol according to claim 10, wherein the average particle size of the metal oxide particles in the metal oxide sol as measured by a dynamic light scattering method is 5 to 200 nm.

12. The metal oxide sol according to claim 10, wherein the organic solvent is an alcohol, a ketone, an ether, an ester, an amide, a glycol, or a hydrocarbon.

13. The metal oxide sol according to claim 10, 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.

14. A metal oxide sol according to claim 10, which is dried under drying conditions of 60 to 100°C and 50 Torr and then redispersed in an organic solvent, and which has an average particle size (nm) of metal oxide particles in the dispersion solvent as measured by dynamic light scattering, such that 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) is 0.6 to 3.

0.

15. A metal oxide sol according to claim 10, in which 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 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.

16. Metal oxide particles having a refractive index of 1.4 to 3.0, wherein 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 at a metal oxide concentration of 60 mass% has a ratio of (EMS viscosity of redispersed metal oxide sol) / (EMS viscosity of dispersion medium) of 1 to 3,000, and the dispersion medium is an organic solvent or a reactive monomer.

17. Metal oxide particles having a refractive index of 1.1 to 1.4, wherein 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.

18. A metal oxide sol comprising the metal oxide particles according to claim 16 or 17 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.

19. A dispersion varnish composition comprising the metal oxide particles according to any one of claims 1 to 9 and an organic component.

20. The dispersion varnish composition according to claim 19, wherein the organic component comprises at least one monomer selected from 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, a fluorine-containing compound, a cyclic olefin-containing compound, ethylene, propylene, or a silane, or a polymer containing such a component.

21. A composite composition comprising the metal oxide particles according to any one of claims 1 to 9 and an organic resin material or a polysiloxane resin.

22. The composite composition according to claim 21, 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.

23. The dispersion varnish composition according to claim 19, which is used for semiconductor device materials, semiconductor element materials, semiconductor resist materials, nanoimprinting, insulating film materials, copper-clad laminate materials, printed circuit board materials, printing plate materials, printing ink materials, pigments, paints, sealant materials, hard coat materials, 3D printing materials, anti-reflective film materials, structural color forming members, automotive parts materials, electronic parts materials, machine element parts, adhesive materials, battery materials, power generation materials, electrostatic 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.

24. The composite composition according to claim 21, which is used for a semiconductor device material, a semiconductor element material, a semiconductor resist material, a nanoimprint material, 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 an in-vehicle part, a material for an electronic part, a machine element part, a material for an adhesive, a material for a battery, a power generation material, 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 a liquid crystal display, a material for an organic electroluminescence 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.

25. A method for producing metal oxide particles according to any one of claims 5 to 9, comprising 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) defined in formula (1) defined in claim 4 and a silane compound (B) selected from the group consisting of formulas (2) and (3) defined in claim 5, and a basic compound (I) to the metal oxide sol obtained in step (A); and step (C): drying the metal oxide sol obtained in step (B).

26. A method for producing a metal oxide sol according to claim 10, further comprising the following step (D) in addition to steps (A) to (C) according to claim 25: step (D): dispersing the metal oxide particles obtained in step (C) in an organic solvent.

27. A method for producing metal oxide particles according to any one of claims 1 to 9, comprising the following steps (E) to (G): step (E): adding water to a dispersion liquid in which metal oxide particles are dispersed in an organic solvent; step (F): removing the supernatant solvent after step (E) to obtain a precipitate; and step (G): drying the precipitate after step (F) to obtain a metal oxide particle powder.

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