Inorganic particle-dispersed organosol having high dispersion stability and method for producing same

Abstract

[Problem] To provide an organosol containing tetracoordinated aluminum atom-containing inorganic particles that have high dispersion stability in an organic solvent. [Solution] Provided are: an inorganic particle-dispersed organosol containing tetracoordinated aluminum atom-containing inorganic particles and an organic solvent, wherein the amount of aluminum atoms present in all of the inorganic particles is 100-50,000 ppm relative to the mass of the inorganic particles in terms of Al2O3, and the anion is contained in an amount of 0.1-50 ppm relative to the mass of the inorganic particle-dispersed organosol; and a method for producing the inorganic particle-dispersed organosol.

Description

Highly dispersion-stable inorganic particle dispersion organosol and method for producing the same

[0001] The present invention relates to an organosol in which inorganic particles containing four-coordinate aluminum atoms are dispersed, and more particularly to an inorganic particle-dispersed organosol with high dispersion stability, a method for producing the same, and a resin composition containing the organosol.

[0002] Silica sols are used in various fields as abrasives and functional inorganic fillers. Although silica sols are stable and do not gel in alkaline environments, when alkaline silica sols are incorporated into compositions using organosilicon compounds or resins as binders, they tend to become cloudy or thicken due to their alkalinity. Furthermore, when preparing organo-silica sols by solvent substitution, mixing with alcohols or other substances can lead to gelation, posing a challenge. On the other hand, in acidic environments, the low zeta potential of silica particles results in low electrical repulsion, making silica sols unstable and prone to gelation. Nevertheless, silica sols are often required in acidic environments, such as in acidic abrasives, raw materials for ceramic fibers, and chromium-based surface treatment agents.

[0003] A known method for improving the stability of silica sols in acidic regions involves modifying the surface of silica particles with an aluminum compound. In this method, aluminosilicate sites are formed on the surface of the silica particles by the reaction of aluminate ions derived from the aluminum compound with silanol groups on the surface of the silica particles. The aluminosilicate sites impart a negative charge to the silica particles, that is, the negative zeta potential of the silica particles increases, thereby improving the dispersion stability of the silica particles in the dispersion medium. In particular, the compatibility between silica particles and highly polar organic solvents and charged resins is improved. For example, in a dispersion of solid silica particles, Al ２ O ３ / SiO ２ A method for producing an acidic silica sol is disclosed, which involves adding an alkaline aluminate aqueous solution so that the molar ratio is greater than 0.0006 and less than or equal to 0.004, heating the solution at 80 to 250°C, and then performing cation exchange on the resulting silica sol (see Patent Document 1).

[0004] Furthermore, hollow silica particles, which have a silica outer shell and a space inside the outer shell, possess characteristics such as low refractive index, low thermal conductivity (thermal insulation), and electrical insulation. Hollow silica particles consist of a core corresponding to a cavity and an outer shell forming the outside of the core. An aqueous dispersion of hollow silica particles can be obtained by forming a silica layer on the outside of template particles in an aqueous medium, and then removing the template particles. For example, a method has been disclosed in which core-shell particles are produced by reacting a silane compound and an aluminum precursor with an organic polymer in a micelle or inverse micelle form in a Si / Al molar ratio of 7 to 15 to form an aluminosilicate shell, reacting this with a basic aqueous solution or an acidic aqueous solution to simultaneously form pores in the shell (outer shell) and remove the core, and then performing a hydrothermal reaction by heating at 160 to 200°C to produce a hollow silica sol with a high density of shell (see Patent Document 2).

[0005] Japanese Patent Publication No. Hei 6-199515, Korean Patent Publication No. 10-1659709

[0006] To stabilize silica sols containing hollow silica particles with cavities inside their outer shells, the particles are modified from the outside with an aluminum compound (i.e., impregnated with the aluminum compound). The aluminum compound penetrates the outer shell, and the aluminum compound that remains on the outside of the shell (impregnated) and the aluminum compound that reaches the inside of the shell (impregnated) each form aluminosilicate sites. Cationic components such as alkali metal ions, which are present within the silica particles and originate from alkali metal silicates, the raw material for silica sol, are captured by these aluminosilicate sites. However, depending on the manufacturing conditions, usage conditions, and storage conditions of the silica particles, cationic components such as alkali metal ions encapsulated within the silica particles may be released from the system over time, resulting in an increase in the pH of the system and causing the aforementioned instability. In the case of hollow silica particles, cationic components such as alkali metal ions present in the aluminosilicate sites on the outside of the outer shell can be removed during manufacturing by cation exchange, but cationic components such as alkali metal ions present in the aluminosilicate sites on the inside of the outer shell are difficult to remove during manufacturing. Furthermore, since aluminosilicate can be formed even inside the silica particles, which do not normally participate in the dispersion stabilization of silica particles, the amount of aluminum present in the aluminosilicate per silica particle increases, and as a result, the amount of cationic components such as alkali metal ions bound to the aluminosilicate also increases. Moreover, there is a possibility that these alkali metals may leach into the dispersion medium through the pores of the outer shell over time, which can lead to an increase in the pH of the system and may impair the storage stability of silica sols containing hollow silica particles.

[0007] On the other hand, when applying silica sols to a wide variety of fields, for example, when mixing them with resin materials to create composite materials, using organosols dispersed in organic solvents can be advantageous from a manufacturing perspective. Furthermore, when mixing with highly hydrophobic resin materials, using organosols dispersed in even more hydrophobic organic solvents can be advantageous for uniformly dispersing inorganic particles in the resin material. However, polyvalent ionic components such as hexa-coordinate aluminum and sulfuric acid contained in inorganic particle dispersion sols generally tend to gel or precipitate when dispersed in highly hydrophobic organic solvents, making long-term storage difficult, and also causing problems such as the generation of foreign matter during the curing process of resin materials.

[0008] In view of the above circumstances, the present inventors conducted diligent studies and found that by defining the amount of aluminum present in the entire inorganic particles and the amount of anions contained in the inorganic particle dispersion sol, it is possible to obtain an inorganic particle dispersion organosol that has high dispersion stability in organic solvents and suppresses the generation of foreign substances derived from polyvalent ion components.

[0009] In other words, the present invention, in first view, is an inorganic particle dispersion organosol comprising four-coordinate aluminum atom-containing inorganic particles, an anion, and an organic solvent, wherein the amount of aluminum atoms present in the entire inorganic particles is Al ２ O ３The present invention relates to an inorganic particle-dispersed organosol in which the anion is present in an amount of 100 to 50,000 ppm relative to the mass of the inorganic particles, and in an amount of 0.1 to 50 ppm relative to the mass of the inorganic particle-dispersed organosol. The present invention relates to the inorganic particle-dispersed organosol according to the first invention, wherein the amount of TN (total nitrogen) contained in the inorganic particle-dispersed organosol is 0.01 to 0.20 mass% relative to the mass of the inorganic particles. The present invention relates to the inorganic particle-dispersed organosol according to the first invention, wherein in a thermal stability test in which the inorganic particle-dispersed organosol is held at 50°C for 4 weeks, the (pH after thermal stability test) - (pH before thermal stability test) of the organosol is less than 4.0, and (average particle diameter by dynamic light scattering method after thermal stability test) / (average particle diameter by dynamic light scattering method before thermal stability test) × 100 (%) is less than 20%. The fourth aspect relates to the inorganic particle-dispersed organosol according to the first aspect, wherein the anion contains a sulfate ion, and the content of the sulfate ion is less than 30 ppm relative to the mass of the inorganic particle-dispersed organosol. The fifth aspect relates to the inorganic particle-dispersed organosol according to the first aspect, wherein the inorganic particles are solid silica particles containing four-coordinate aluminum atoms or hollow silica particles containing four-coordinate aluminum atoms. The sixth aspect relates to the inorganic particle-dispersed organosol according to the first aspect, wherein the inorganic particles satisfy the following (i) to (iv): (i) the average primary particle diameter measured by a transmission electron microscope is 5 nm to 100 nm; (ii) the average particle diameter measured by dynamic light scattering is 5 nm to 150 nm; (iii) the inorganic particle content in the inorganic particle-dispersed organosol is 10% to 70% by mass; (iv) the acidity is 0.01 to 1.00 μmol / m ２ The seventh viewpoint relates to the inorganic particle dispersion organosol described in the fifth viewpoint, wherein the hollow silica particles satisfy the following (V) to (Vii): (V) The outer shell thickness of the hollow silica particles is 2 to 15 nm; (Vi) The surface charge amount of the hollow silica particles, calculated per gram, is 10 μeq / g to 200 μeq / g; (Vii) The carbon content of the hollow silica particles, as determined by elemental analysis, is 0.1 mass% to 10.0 mass%. The eighth viewpoint is, ２７In the Al-NMR measurement, when acetylacetone is added to the inorganic particle-dispersed organosol at 1000 ppm with respect to the mass concentration of the inorganic particles and evaluated, it relates to the inorganic particle-dispersed organosol according to the first aspect, which has one or more peaks indicating aluminum atoms other than tetracoordinated aluminum atoms. As a ninth aspect, at least a part of the inorganic particles is coated with a silane compound, and the silane compound is at least one silane compound selected from the group consisting of compounds represented by the following formula (1) and formula (2): (In formula (1), R １ is a group bonded to a silicon atom, and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group and bonded to the silicon atom by a Si-C bond, or represents a combination of these groups, and R ２ is a group or atom bonded to a silicon atom, and independently represents an alkoxy group, an acyloxy group, a hydroxy group, or a halogen atom, or represents a combination of these groups or atoms, a represents an integer of 1 to 3. In formula (2), R ３ is a group bonded to a silicon atom, and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, a polyether group, a carboxy group, a protected carboxy group, a carboxy group-generating group, an imide group, or a cyano group and bonded to the silicon atom by a Si-C bond, or represents a combination of these groups, and R ４(where b is a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof; Y is a group or atom bonded to a silicon atom, representing an alkylene group, an NH group, or an oxygen atom; b represents an integer from 1 to 3; and c represents an integer of 0 or 1.) As a tenth point of view, the inorganic particles have a surface area of ​​1 nm ２ The present invention relates to an inorganic particle dispersion organosol according to the ninth aspect, wherein the particles are coated on the surface with the silane compound at a rate of 0.1 to 10 particles per unit, or the silane compound is bound to the surface of the particles. The present invention relates to an inorganic particle dispersion organosol according to the first aspect, wherein the organic solvent comprises at least one selected from the group consisting of alcohols, ketones, ethers, esters, and amides. The twelfth aspect further comprises a reactive monomer, wherein the reactive monomer is at least one selected from the group consisting of (meth)acrylic compounds, polyfunctional (meth)acrylates, 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 anhydride, bismaleimide, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, propylene, or at least one silane compound selected from the group consisting of compounds represented by the following formulas (1) and (2). (In formula (1), R １ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups.２ R is a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof, where a is an integer from 1 to 3, and in formula (2), R ３ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ４ (wherein b is a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof; Y is a group or atom bonded to a silicon atom, representing an alkylene group, an NH group, or an oxygen atom; b represents an integer from 1 to 3; c represents an integer of 0 or 1.) As a thirteenth viewpoint, a resin composition comprising four-coordinate aluminum atom-containing inorganic particles and a polymer, wherein the amount of aluminum atoms present in the entire inorganic particles is Al ２ O ３The present invention relates to a resin composition in which the amount of the inorganic particles is 100 to 50,000 ppm in terms of the mass of the inorganic particles, and the polymer is a polymer containing as a monomer component at least one monomer selected from the group consisting of (meth)acrylic compounds, polyfunctional (meth)acrylates, 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 anhydride, bismaleimide, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, and propylene. The fourteenth aspect relates to an inorganic particle dispersion organosol or a resin composition according to the thirteenth aspect that has an application as a material for anti-reflective coatings. The 15th aspect relates to a method for producing an inorganic particle-dispersed organosol according to the 1st aspect, comprising the step of replacing the dispersed water of an inorganic particle aqueous dispersion sol containing four-coordinate aluminum atom-containing inorganic particles and having a pH of 5 to 12 with an organic solvent by ultrafiltration, heating under reduced pressure, or heating under normal pressure. The 16th aspect relates to a method for producing an inorganic particle-dispersed organosol according to the 15th aspect, comprising the step of further cation exchange after the step of replacing the dispersed water of the aqueous dispersion sol with an organic solvent. The 17th aspect relates to a method for producing an inorganic particle-dispersed organosol according to the 16th aspect, comprising the step of further adding at least one silane compound selected from the group consisting of compounds represented by the following formulas (1) and (2) to the inorganic particle aqueous dispersion sol or inorganic particle-dispersed organosol containing four-coordinate aluminum atom-containing inorganic particles, and heating and stirring at 10°C to 95°C for 0.1 hours to 20 hours. (In formula (1), R １R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ２ R is a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof, where a is an integer from 1 to 3, and in formula (2), R ３ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ４ (wherein a 18th aspect is a method for producing an inorganic particle dispersion organosol according to the 15th aspect, comprising a step of replacing the dispersion medium with a reactive monomer, polymer, or an organic solvent with a lower dielectric constant after the step of replacing with the organic solvent.)

[0010] According to the present invention, it is possible to provide an inorganic particle dispersion organosol that has high dispersion stability and suppresses the generation of foreign matter derived from polyvalent ion components.

[0011] The present invention relates to an inorganic particle dispersion organosol containing four-coordinate aluminum atom-containing inorganic particles (hereinafter also simply referred to as "inorganic particles"), anions, and an organic solvent, wherein the amount of aluminum present in the total amount of inorganic particles, and in particular the amount of anions contained in the inorganic particle dispersion organosol, is within a predetermined range.

[0012] As described above, the four-coordinate aluminum atom-containing inorganic particles according to the present invention are particles containing four-coordinate aluminum atoms. As will be described later, these inorganic particles appear to be four-coordinate aluminum atom-containing inorganic particles because at least the aluminum atoms form aluminosilicate sites on their surface. On the other hand, aluminum atoms that are freed in the dispersion medium without being able to form the aluminosilicate sites take the form of six-coordinate aluminum atoms, etc. Six-coordinate aluminum atoms can exist on the surface of inorganic particles (e.g., silica particles) in organic solvents, and can particularly exist around hydroxyl groups (silanol groups in the case of silica particles) on the particle surface. Unlike in water, these six-coordinate aluminum atoms themselves do not have ionic properties in organic solvents and therefore do not exhibit aggregation. Furthermore, these six-coordinate aluminum atoms exhibit the effect of imparting charge to the surface of inorganic particles, which can improve storage stability by preventing inorganic particles from bonding with each other. However, when these six-coordinate aluminum atoms come into contact with anions added to adjust the pH of the sol, such as sulfuric acid, some of them become aluminum sulfate. Aluminum sulfate is a compound with high cohesive power, so much so that it is used as a flocculant. When aluminum sulfate reacts with alkali metals in the dispersion medium to produce positively charged aluminum hydroxide, it neutralizes the negative charge on the surface of inorganic particles, causing aggregation and increasing the viscosity of the sol. Furthermore, when mixed with highly hydrophobic organic solvents or resins, the aluminum hydroxide itself precipitates, causing foreign matter problems. In this invention, we have found that by defining the amount of anions in the inorganic particle dispersion organosol within the above predetermined range, the generation of foreign matter originating from the contact between anions and aluminum atoms other than 4-coordinate atoms, such as 6-coordinate aluminum atoms, is suppressed. Consequently, a sol with excellent dispersion stability is obtained, in which the change in particle size of inorganic particles before and after long-term storage is small and the aggregation of the particles is suppressed.

[0013] The inorganic particle-dispersed organosol according to the present invention is a dispersion system in which inorganic particles and anions are dispersed in an organic solvent as the dispersion medium. As the inorganic particles, solid silica particles (hereinafter also simply referred to as "silica particles") or hollow silica particles (hereinafter also simply referred to as "hollow silica particles" or "hollow silica") can be used. The hollow silica particles are silica (SiO ２ It is a particle that has an outer shell containing ) and has a space inside the outer shell.

[0014] The amount of anions contained in the above inorganic particle-dispersed organosol is 0.1 to 50 ppm relative to the mass of the organosol, and can be, for example, 1 to 40 ppm or 1 to 30 ppm. By setting the amount of anions contained in the above inorganic particle-dispersed organosol to 0.1 to 50 ppm, it is possible to suppress the increase in viscosity of the sol and improve its fluidity, as well as suppress the generation of foreign matter derived from the anionic component.

[0015] The above-mentioned anions include one or more selected from the group consisting of inorganic anions, for example, inorganic anions selected from the group consisting of sulfate ions, nitrate ions, carbonate ions, chloride ions, and phosphate ions.

[0016] The amount of sulfate ions, one of the anions mentioned above, is preferably less than 30 ppm, less than 10 ppm, less than 8 ppm, or less than 5 ppm relative to the mass of the inorganic particle-dispersed organosol of the present invention. It is desirable that the inorganic particle-dispersed organosol of the present invention contains as little sulfate ions as possible, for example, that the amount of sulfate ions be 0 ppm, however, contamination as an impurity or the presence of sulfate ions at residual levels during the sol purification process may occur. By keeping the amount of sulfate ions contained in the inorganic particle-dispersed organosol to less than 10 ppm, even if the 4-coordinate aluminum atoms forming the aluminosilicate site are removed and aluminum atoms other than 4-coordinate, particularly 6-coordinate aluminum atoms, are present in the system, the formation of aluminum sulfate resulting from contact between these 6-coordinate aluminum atoms and sulfate ions, as well as the formation of associated aggregates and precipitates, can be suppressed.

[0017] Furthermore, the amount of TN (total nitrogen) contained in the inorganic particle-dispersed organosol according to the present invention can be, for example, 0.01 to 0.20% by mass, or 0.05 to 0.16% by mass, relative to the mass of the inorganic particles. The "amount of TN (total nitrogen) contained in the inorganic particle-dispersed organosol" refers to the sum of the amount of nitrogen contained in the inorganic particles themselves and the amount of nitrogen contained in the organosol, i.e., the organic solvent. By setting the amount of TN in the inorganic particle-dispersed organosol to 0.01 to 0.20% by mass, the amount of nitrogen-containing compounds, such as ammonia, that leach from the inorganic particles over time can be reduced, and the rise in pH of the inorganic particle-dispersed organosol during long-term storage can be suppressed. The amount of TN contained in the inorganic particle-dispersed organosol can be measured, for example, using a trace nitrogen analyzer manufactured by Nitto Seikou Analytech Co., Ltd. (formerly Mitsubishi Chemical Analytech Co., Ltd.).

[0018] The inorganic particle-dispersed organosol of the present invention can be evaluated for stability in a thermal stability test, for example, by evaluating the change in pH value and the rate of change in particle size before and after the test, in a thermal stability test held at 50°C for 4 weeks. That is, the pH value of the organosol before the thermal stability test is (Y ０ ), the pH value of the organosol after the thermal stability test is (Y ４ｗ When this is the case, the change in pH value before and after the test is (Y ４ｗ ) - (Y ０ The stability of the sol is evaluated as (1). The average particle size obtained by dynamic light scattering before the thermal stability test is (X ０ ), the average particle size after the thermal stability test is determined by dynamic light scattering (X ４ｗ When this is the case, the rate of change in particle size before and after the test is: [(X ４ｗ ) - (X ０ ) ] / (X ０ ) × 100 (%) is used as the evaluation of sol stability (2). And in the inorganic particle dispersion organosol of the present invention, evaluation (1) [change in pH value before and after the test: (Y ４ｗ ) - (Y ０ )] is less than 4.0, and evaluation (2) [Percentage change in particle size before and after the test: [(X ４ｗ ) - (X ０ ) ] / (X ０It is preferable that the sol has thermal stability such that [) × 100 (%)] is less than 20%. The amount of change in the above evaluation (1) can be, for example, less than 3.0 or less than 2.5. The rate of change in the above evaluation (2) can be, for example, less than 15%.

[0019] In the above four-coordinate aluminum atom-containing inorganic particles, the amount of aluminum atoms present in the entire inorganic particle (i.e., the entire particle including the surface and interior of the particle) (in short, the aluminum atom content in the inorganic particle) is Al ２ O ３ The amount of aluminum atoms present in the inorganic particles is calculated to be 100 to 50,000 ppm relative to the mass of the inorganic particles. For example, it can be 100 to 20,000 ppm, or 100 to 15,000 ppm, or 100 to 10,000 ppm, or 100 to 5,000 ppm, or 100 to 2,000 ppm. The amount of aluminum atoms present in the entire inorganic particles can be determined by a dissolution method using hydrofluoric acid aqueous solution (also called hydrofluoric acid aqueous solution). Specifically, the amount of aluminum atoms present in the entire inorganic particles is determined by dissolving the hollow silica particles in hydrofluoric acid aqueous solution and measuring and analyzing the resulting solution using an ICP emission spectrometer. ２ O ３ It can be expressed in terms of . More specifically, the procedure is as follows: First, the target inorganic particle dispersion organosol is dried to remove the dispersion medium and obtain inorganic particles. 250 mg of these inorganic particles are dissolved in an aqueous hydrofluoric acid solution (for example, a mixture of 2.5 ml of 60% nitric acid and 2.5 ml of 38% hydrofluoric acid) to obtain an aqueous solution. The amount of aluminum atoms in the aqueous solution is measured using an ICP emission spectrometer, and Al ２ O ３ The aluminum atom content (ppm) is obtained by converting this to a fraction of a percent. By dividing this by the mass of the inorganic particles, the total amount of aluminum atoms present in the inorganic particles (Al ２ O ３ The amount of aluminum atoms present in the entire particle can be determined in ppm. In this specification, when the inorganic particles are hollow silica particles or solid silica particles, the amount of aluminum atoms present in the entire particle is expressed in units of ppm / SiO2, which represents the amount relative to the mass (g) of the hollow / solid silica particles. ２It may sometimes display as "[...]".

[0020] The average primary particle diameter of the four-coordinate aluminum atom-containing inorganic particles according to the present invention can be 5 to 100 nm as observed by a transmission electron microscope (TEM), for example, in the range of 20 to 100 nm, 30 to 100 nm, 30 to 80 nm, or 30 to 70 nm, or also in the range of 5 nm to 50 nm, 5 nm to 30 nm, 5 nm to 20 nm, or 5 to 10 nm.

[0021] Furthermore, in the inorganic particle dispersion organosol according to the present invention, the average particle diameter (DLS average particle diameter: Z average particle diameter, harmonic mean particle diameter) of the four-coordinate aluminum atom-containing inorganic particles determined by dynamic light scattering (DLS method) is, for example, 5 to 150 nm, and preferably can be in the range of, for example, 20 to 150 nm, 30 to 150 nm, 40 to 150 nm, 40 to 120 nm, or 40 to 100 nm. The DLS average particle diameter represents the average value of the secondary particle diameter (dispersed particle diameter), and it can be determined that the larger the DLS average particle diameter, the more aggregated the silica particles in the medium are.

[0022] Furthermore, in the inorganic particles according to the present invention, the specific surface area obtained by the BET method (nitrogen gas adsorption method) is, for example, 18 m². ２ / g to 1,000m ２ It can be expressed as / g. For example, if the inorganic particles are hollow silica particles, the specific surface area can be 18 to 200 m². ２ / g, or 50-160m ２ / g, or 60-160m ２ / g, or 70-160m ２ / g, or 80-150m ２ It can be expressed as / g. Also, for example, if the inorganic particles are solid silica particles, the specific surface area can be 50 to 1,000 m². ２ / g, or 80m ２ / g to 1,000m ２ / g, or 100m ２ / g to 1,000m ２ / g, or 200m ２ / g to 1,000m ２ / g, or 250m ２ / g to 1,000m２ / g, or 300m ２ / g to 800m ２ It can be expressed as / g.

[0023] The inorganic particles contained in the inorganic particle-dispersed organosol can be in proportions of 10% to 70% by mass, 15% to 70% by mass, or 15% to 50% by mass, for example, approximately 20% to 35% by mass. By setting the proportion of inorganic particles in the inorganic particle-dispersed organosol to 10% to 70% by mass, the amount of solvent derived from the inorganic particle-dispersed organosol can be reduced when compositing with a resin. In this specification, the concentration of inorganic particles in the organosol is a value obtained by a calcination method, specifically, by calcining the target organosol at 1000°C for 30 minutes or more, and dividing the mass of the calcined residue obtained by the mass of the target organosol. Furthermore, when hollow silica particles and solid silica particles are used in combination in an inorganic particle dispersion organosol, the amount added can be, for example, in mass ratio, hollow silica particles:solid silica particles = 100:1 to 100:25, or 100:3 to 100:20, or 100:5 to 100:20, or 100:8 to 100:15.

[0024] Furthermore, the inorganic particles contained in the inorganic particle dispersion organosol have an acidity of 0.01 to 1.00 μmol / m³. ２ Particles such as those with an acidity of 0.01 to 0.50 μmol / m³ ２ The particles can be such that the acidity of the inorganic particles is 0.01 to 1.00 μmol / m ２ When the range is such that the charge repulsion of inorganic particles becomes stronger, it is expected that this will lead to an improvement in the dispersibility of particles in the sol. In this invention, the acidity of the particles is the amount of base per unit surface area required to neutralize the particles ( mmol / m³). ２ It is defined as follows. For example, for the target organosol, unwanted ions can be removed using cation exchange resin and anion exchange resin as needed, then neutralization titration is performed to determine the amount of base required for neutralization, and this is divided by the surface area of ​​the particles (for example, the specific surface area value obtained by nitrogen gas adsorption method) to determine the acidity of the particles.

[0025] Furthermore, when the four-coordinate aluminum atom-containing inorganic particles according to the present invention are hollow silica particles, their outer shell can be observed with a transmission electron microscope (TEM) and its thickness can be determined. In the case of the above-mentioned hollow silica particles, the thickness of the outer shell observed with a transmission electron microscope can be, for example, in the range of 2.0 to 15.0 nm, or 3.0 to 12.0 nm, preferably 3.0 to 8.0 nm.

[0026] Furthermore, the hollow silica particles preferably have a surface charge (negative charge) per gram of hollow silica particles of, for example, 10 to 250 μeq / g, or it can be in the range of 10 to 150 μeq / g, 10 to 100 μeq / g, 10 to 50 μeq / g, or 10 to 45 μeq / g. The lower limit of the surface charge may be 10 μeq / g, 20 μeq / g, or 25 μeq / g, and the upper limit may be 45 μeq / g or 40 μeq / g.

[0027] Furthermore, in the acidic region, the high absolute value of the zeta potential of the hollow silica particles causes electrical repulsion, which is desirable from the viewpoint of dispersibility. The surface charge of the hollow silica particles changes, as one factor, depending on the amount of aluminum atoms (aluminosilicate) present in the hollow silica particles, as described above. For example, the amount of aluminum atoms (Al) present throughout the silica particles... ２ O ３ Conversion, SiO ２ The amount is 120 ppm / SiO ２ If the value is less than the limit, the stability of the hollow silica particles tends to decrease. On the other hand, the aluminum atoms (Al) present throughout the silica particles tend to decrease. ２ O ３ Conversion, SiO ２ The amount is 50,000 ppm / SiO ２ In the above cases, at the aqueous sol stage, the particle size after doping tends to increase compared to the dynamic light scattering particle size (DLS particle size) before doping with aluminum atoms.

[0028] Furthermore, the hollow silica particles described above can have a carbon content measured by elemental analysis in the range of, for example, 0.1% to 10.0% by mass. A sample of hollow silica particles to be used for elemental analysis can be prepared by first selecting a poor solvent and a good solvent from a hollow silica sol in which the hollow silica particles to be measured are dispersed, separating the hollow silica particles from organic components not bound to the hollow silica particles using a centrifuge or the like, and then drying the resulting mixture to remove even the adsorbed water. The carbon content (%) in the sample can be obtained by measuring the resulting silica particle sample with an elemental analyzer.

[0029] Furthermore, the refractive index of the hollow silica particles can be in the range of, for example, 1.20 to 1.45, 1.20 to 1.40, or 1.20 to 1.30.

[0030] Now, the inorganic particle dispersion organosol according to the present invention is ２７ From the peak positions of the spectra obtained by Al-NMR measurement, it is possible to determine whether the aluminum in the system exists as aluminosilicate sites (four-coordinate aluminum atoms) formed on the particle surface, or as eluted into the system and cationized (aluminum atoms other than four-coordinate (e.g., three-coordinate or six-coordinate)). Specifically, in a sample in which acetylacetone was added at a concentration of 1000 ppm relative to the mass concentration of inorganic particles to an inorganic particle dispersion organosol, ２７ Al-NMR measurements are performed to evaluate the peak positions in the spectrum. ２７ The peak indicating four-coordinate aluminum atoms, obtained by Al-NMR measurement, is observed around 54 ppm (50-65 ppm), while the peak indicating aluminum atoms other than four-coordinate, mainly six-coordinate aluminum atoms, is observed around 0 ppm (0-10 ppm). As mentioned above, the presence of six-coordinate aluminum atoms can have the effect of improving storage stability. Therefore, when the amount of anions in the system is within a predetermined range (for example, when the amount of sulfate ions in the system is reduced), ２７In Al-NMR measurements, a preferred embodiment may be a sol having peaks originating from four-coordinate aluminum atoms as well as peaks originating from aluminum atoms other than four-coordinate atoms.

[0031] The four-coordinate aluminum atom-containing inorganic particles according to the present invention may be particles in which at least a portion of their surface is coated with a silane compound represented by formula (1) or formula (2) described later. In the present invention, "coated with a silane compound" refers to a state in which the surface of the inorganic particle is coated with a silane compound, and also includes a state in which the silane compound is bonded to the surface of the inorganic particle. "A state in which the surface of the inorganic particle is coated with a silane compound" means a state in which the silane compound coats at least a portion of the surface of the inorganic particle, that is, a state in which the silane compound covers a part of the surface of the inorganic particle, and a state in which the silane compound covers the entire surface of the inorganic particle. This state does not depend on whether or not the silane compound is bonded to the surface of the inorganic particle. Furthermore, "a mode in which the silane compound is bonded to the surface of inorganic particles" means that the silane compound is bonded to at least a part of the surface of the inorganic particles, that is, a mode in which the silane compound is bonded to a part of the surface of the inorganic particles, a mode in which the silane compound is bonded to a part of the surface of the inorganic particles and covers at least a part of the surface, and a mode in which the silane compound is bonded to the entire surface of the inorganic particles and covers the entire surface. In other words, the silane compound can function as a surface modifier for four-coordinate aluminum atom-containing inorganic particles. The silane compound can be used to control the surface state of four-coordinate aluminum atom-containing inorganic particles to one that has high affinity for various dispersion media, thereby improving the dispersion stability in the dispersion media, and is expected to contribute to improving the stability of the inorganic particle dispersion organosol.

[0032] Examples of the silane compounds mentioned above include at least one silane compound selected from the group consisting of compounds represented by the following formulas (1) and (2). In the above formula (1), R １R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ２ R is a group or atom bonded to a silicon atom, which independently represents an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof, where a is an integer from 1 to 3. In the definition of a group in a silane compound as used herein, "independently" means that multiple groups can each independently represent a group defined as an option. That is, for example, in formula (1), R １ If there are two or more (a is 2 to 3), then there are multiple R １ These may be the same group (for example, all methyl groups) or a combination of different groups (for example, a methyl group and a phenyl group, or a methyl group and a (meth)acryloylpropyl group when a is 2).

[0033] In the above formula (2), R ３ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or a combination of these groups. ４ b represents a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof; Y represents a group or atom bonded to a silicon atom, representing an alkylene group, an NH group, or an oxygen atom; b represents an integer from 1 to 3; and c represents an integer of 0 or 1.

[0034] In the above formula, examples of alkyl groups include linear or branched alkyl groups having 1 to 18 carbon atoms, and cyclic alkyl groups having 3 to 10 carbon atoms. Examples include, but are not limited to, methyl groups, ethyl groups, linear, branched, or cyclic propyl groups, butyl groups, pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, and decyl groups.

[0035] The above-mentioned halogenated alkyl group is an alkyl group substituted with one or more halogen atoms. Specific examples of such alkyl groups include those described above, namely linear or branched alkyl groups having 1 to 18 carbon atoms, and cyclic alkyl groups having 3 to 10 carbon atoms. Examples of the halogen atoms include fluorine atoms (for example, as a trifluoropropyl group), chlorine atoms, bromine atoms, iodine atoms, and the like.

[0036] Examples of the above-mentioned alkenyl groups include alkenyl groups having 2 to 10 carbon atoms, which may be linear, branched, or cyclic, and the position of the double bond in the alkenyl group is not particularly limited. Examples include, but are not limited to, ethenyl groups (vinyl groups), linear, branched, or cyclic propenyl groups, butenyl groups, pentenyl groups, and hexenyl groups.

[0037] The above-mentioned aryl group may include, for example, an aryl group having 6 to 30 carbon atoms, such as a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-pyrenyl group, a 2-pyrenyl group, and so on.

[0038] Examples of organic groups having the epoxy group mentioned above include glycidoxymethyl group, glycidoxyethyl group, glycidoxypropyl group, glycidoxybutyl group, and 2-(3,4-epoxycyclohexyl)ethyl group. The (meth)acryloyl group mentioned above refers to both the acryloyl group and the methacryloyl group. Examples of organic groups having the (meth)acryloyl group include methacryloyloxymethyl group, acryloyloxymethyl group, methacryloyloxyethyl group, acryloyloxyethyl group, 3-methacryloyloxypropyl group, and 3-acryloyloxypropyl group. Note that methacryloyloxy group and acryloyloxy group are also called methacryloxy group and acryloxy group. Examples of organic groups having the mercapto group mentioned above include ethyl mercapto group, 3-mercaptopropyl group, butyl mercapto group, hexyl mercapto group, octyl mercapto group, and mercaptophenyl group. Examples of organic groups having the above-mentioned amino group include aminomethyl group, 2-aminoethyl group, 3-aminopropyl group, N-2-(aminoethyl)-3-aminopropyl group, N-(1,3-dimethyl-butylidene)aminopropyl group, N-phenyl-3-aminopropyl group, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl group, dimethylaminoethyl group, and dimethylaminopropyl group. Examples of organic groups having the above-mentioned carboxyl group include carboxymethyl group, carboxyethyl group, carboxypropyl group, and carboxybutyl group. Furthermore, the above-mentioned protected carboxyl group refers to a carboxyl group protected by a protecting group used in ordinary organic synthesis reactions. Furthermore, the above-mentioned carboxyl group generating group refers to a group in which the carboxyl group is esterified or amidated by alcohols, amines, etc.Specific examples of silane compounds containing organic groups having a protected carboxyl group and a carboxyl group generating group include silane coupling agents having a carboxylic acid ester structure. In the silane coupling agent described above, the carboxylic acid ester portion and the alkoxysilyl group may be linked by an alkylene group, or by an alkylene group containing a heteroatom (nitrogen atom, oxygen atom).The silane coupling agent can be used as an amino acid generator because, if the carboxylic acid ester portion undergoes hydrolysis to become a carboxylic acid and contains a nitrogen atom (heteroatom), hydrolysis will result in the formation of an amino acid due to the presence of a carboxyl group and an amino group. For example, the product shown in formula (1-1), manufactured by Shin-Etsu Chemical Co., Ltd., trade name X-88-475, can be used. Examples of organic groups having the above imide group include the N-succinimidyl group. Examples of organic groups having the above cyano group include the cyanoethyl group and the 3-cyanopropyl group.

[0039] The alkoxy group mentioned above may include, but is not limited to, alkoxy groups having 1 to 10 carbon atoms, such as methoxy, ethoxy, propoxy, and isopropoxy groups.

[0040] The above-mentioned acyloxy group is a group derived by removing a hydrogen atom from the carboxyl group (-COOH) of a carboxylic acid compound, and specific examples include acyloxy groups having 2 to 10 carbon atoms.

[0041] Examples of the halogen atoms mentioned above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0042] Furthermore, examples of the alkylene group mentioned above include alkylene groups derived from the alkyl groups described above. Specific examples include, but are not limited to, linear, branched, or cyclic alkylene groups having 1 to 10 carbon atoms, such as methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, and decamethylene groups.

[0043] As a specific example of a silane compound represented by formula (1), for example, a silane compound represented by the following formula (3) can be given.

[0044] In the above formula (3), R ５is a group bonded to a silicon atom, which independently represents an alkyl group having 1 to 3 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an organic group having a (meth)acryloyl group, an alkenyl group, or a carboxy group-generating group and bonded to the silicon atom by a Si—C bond, or represents a combination of these groups, R ６ is a group or atom bonded to a silicon atom, which independently represents an alkoxy group having 1 to 3 carbon atoms or represents a combination of these groups, and d represents an integer of 1 to 3. Specific examples of these groups are those described above, and as the alkyl group having 1 to 3 carbon atoms, an alkyl group having 1 to 3 carbon atoms in the specific examples of the above-mentioned alkyl group can be mentioned.

[0045] Further, as a specific example of the silane compound represented by the above formula (1), for example, a silane compound represented by the following formula (4) can be mentioned. In the above formula (4), R ７ and R ８ are groups bonded to a silicon atom, which independently represent an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 10 carbon atoms, or an organic group having a (meth)acryloyl group and bonded to the silicon atom by a Si—C bond, and R ９ is a group or atom bonded to a silicon atom, which independently represents an alkoxy group having 1 to 3 carbon atoms or represents a combination of these groups. Specific examples of these groups are those described above, and as the alkyl group having 1 to 3 carbon atoms and the aryl group having 6 to 10 carbon atoms, an alkyl group having 1 to 3 carbon atoms and an aryl group having 6 to 10 carbon atoms in the specific examples of the above-mentioned alkyl group and aryl group can be mentioned.

[0046] In addition, as specific examples of the silane compounds represented by the above formula (1) and formula (2), compounds capable of forming a trimethylsilyl group on the surface of silica particles can be mentioned. Those compounds can be exemplified as compounds represented by the following formula (1-2), formula (2-1), and formula (2-2). In the above formula (1-2), R １２The group is an alkoxy group, such as a methoxy group or an ethoxy group. The silane compounds represented by formulas (1-2), (2-1), and (2-2) above can be silane compounds manufactured by Shin-Etsu Chemical Co., Ltd.

[0047] Inorganic particles, in which at least a portion is coated with a silane compound, can be obtained, for example, by adding a silane compound to an inorganic particle dispersion sol and then heat-treating it at 10 to 95°C for about 0.1 to 20 hours. At this time, the amount of silane compound added to the inorganic particles in the inorganic particle dispersion sol can be, for example, a ratio of silane compound / inorganic particles = 0.1 to 10.0 by mass ratio. Note that the inorganic particle dispersion sol used when treating inorganic particles with a silane compound is a sol using an aqueous solvent or an organic solvent as the dispersion medium, and is distinguished from sols using reactive monomers or polymers as the dispersion medium, which will be described later. In one embodiment, the inorganic particles according to the present invention have a surface area of ​​1 nm ２ The particles can be composed of 0.1 to 10 particles per unit, with the surface coated with the silane compound, or particles in which the silane compound is bonded to the surface. That is, the amount of inorganic particle coating (surface treatment) by the silane compound is 1 nm of the inorganic particle surface. ２ The amount can be such that the number of silicon atoms in the silane compound is, for example, about 0.1 to 10, or about 0.1 to 6, or also about 0.1 to 2.

[0048] The treatment (reaction) of inorganic particles with the above-mentioned silane compound proceeds through the reaction between the silanol groups generated by the hydrolysis of the silane compound and the hydroxyl groups (silanol groups in the case of silica particles) on the surface of the inorganic particles. The presence of water is necessary for this hydrolysis, but if the inorganic particle dispersion sol is an aqueous solvent sol, the aqueous solvent can play this role, and if it is an organic solvent sol obtained by solvent substitution of the aqueous medium with an organic solvent, the water remaining in the organic solvent can play this role. For example, water present in the organic solvent at a concentration of 0.01% to 1% by mass can be used for hydrolysis.

[0049] Furthermore, hydrolysis can be carried out with or without a catalyst. If the surface of the inorganic particles is on the acidic side (pH less than 7), hydrolysis can be carried out without a catalyst. When a catalyst is used, examples include metal chelate compounds, organic acids (acetic acid, oxalic acid, lactic acid, etc.), inorganic acids (hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, etc.), organic bases (heterocyclic amines, quaternary ammonium salts, sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, etc.), and inorganic bases (ammonia, sodium hydroxide, potassium hydroxide, etc.).

[0050] [Organic solvent] The inorganic particle dispersion organosol according to the present invention comprises an organic solvent (dispersion medium), and the organic solvent includes, for example, at least one selected from the group consisting of alcohols, ketones, ethers, esters, or amides. More specifically, examples include alcohols having 1 to 10 carbon atoms, ketones having 1 to 10 carbon atoms, ethers having 1 to 10 carbon atoms, esters having 1 to 10 carbon atoms, and amides. The number of carbon atoms refers to the total number of carbon atoms contained in the compound such as the alcohol.

[0051] Examples of alcohols having 1 to 10 carbon atoms include aliphatic alcohols, which may be primary, secondary, or tertiary alcohols. Polyhydric alcohols such as dihydric and trihydric alcohols can also be used. Examples of monohydric primary alcohols include methanol, ethanol, 1-propanol, 1-butanol (n-butanol), and 1-hexanol. Examples of monohydric secondary alcohols include 2-propanol, 2-butanol, cyclohexanol, propylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of monohydric tertiary alcohols include tert-butyl alcohol. Examples of dihydric alcohols (glycols) include methanediol, ethylene glycol, propylene glycol, and diethylene glycol. Examples of trihydric alcohols include glycerin.

[0052] As the ketone having 1 to 10 carbon atoms mentioned above, aliphatic ketones can be preferably used. Examples include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, cyclopentanone, and methylcyclopentanone.

[0053] As the above-mentioned ether having 1 to 10 carbon atoms, aliphatic ethers can be preferably used. Examples include dimethyl ether, ethyl methyl ether, diethyl ether, tetrahydrofuran, 1,4-dioxane, and 3-methyl-3-methoxy-1-butanol.

[0054] As the ester having 1 to 10 carbon atoms mentioned above, aliphatic esters can be preferably used. Examples include methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethyl acrylate, propyl acrylate, dimethyl maleate, diethyl maleate, dipropyl maleate, dimethyl adipate, diethyl adipate, dipropyl adipate, propylene glycol methyl ether acetate, and the like.

[0055] Examples of the above-mentioned amides include N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and tetramethylurea.

[0056] [Reactive Monomers, Polymers] The inorganic particle dispersion organosol according to the present invention may further contain reactive monomers and polymers. Examples of the reactive monomers include (meth)acrylic compounds, polyfunctional (meth)acrylates, vinyl structure-containing compounds (vinyl-containing compounds, divinyl-containing compounds, allyl compounds, diallyl-containing compounds, styrene, ethylene, propylene, cyclic olefin-containing compounds, etc.), 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, ester structure-containing compounds (tetracarboxylic anhydride, lactone ring-containing compounds, lactide-containing compounds, etc.), bismaleimide, fluorine-containing compounds, or at least one silane compound selected from the group consisting of compounds represented by formulas (1) and (2) above. Examples of the polymers include polymers containing at least one monomer selected from the various compounds listed above as reactive monomers as a monomer component.

[0057] Organosols (monomer dispersion sols, polymer dispersion sols) containing these reactive monomers or polymers as dispersion media have a fluid liquid form. From this viewpoint, reactive monomers / polymers that are liquid at 25°C or reactive monomers / polymers with a viscosity of 50,000 mPa·S or less at 25°C are suitably used as dispersion media. While reactive monomers and polymers themselves can be used as dispersion media for sols, if they are solids, gases, or have high viscosity, they can be mixed with the aforementioned organic solvents to form a dispersion media for sols.

[0058] The reactive monomers mentioned above also include compounds having radical polymerizable groups, cationic polymerizable groups, or anionic polymerizable groups in their molecules, or polymerizable compounds having ethylenically unsaturated bonds in their molecules, polymerizable compounds having epoxy rings, polymerizable compounds having oxetane rings, and polymerizable compounds having vinyl ether structures.

[0059] [Basic Compounds] The inorganic particle dispersion organosol according to the present invention may further contain basic compounds. Basic compounds can play a role in adjusting the pH of the organosol and adjusting the surface charge. By adjusting the type and amount of basic compound added, it is possible to adjust the surface charge of the inorganic particles to any desired surface charge. For example, by adding a basic compound, the surface charge of the inorganic particles in the inorganic particle dispersion organosol of the present invention, that is, the surface charge (negative charge) per gram of inorganic particles, can be adjusted to 25 to 250 μeq / g. Alternatively, the surface charge can be set to a range of 25 to 150 μeq / g, or 25 to 100 μeq / g, or 25 to 50 μeq / g, or 25 to 45 μeq / g. Furthermore, by adding a basic compound, the pH of the inorganic particle dispersion organosol of the present invention can be adjusted to, for example, 7 to 10.

[0060] The basic compound can be either an inorganic base or an organic base, and may contain, for example, an amine, or an amine and ammonia. The amine can be added and contained in an amount of 0.001 to 10% by mass, 0.01 to 10% by mass, or 0.1 to 10% by mass relative to the mass of the inorganic particles. The amount of amine, or amine and ammonia as the basic compound, can also be expressed as the total amount of nitrogen in the inorganic particle dispersion organosol. For example, the basic component can be contained such that the total amount of nitrogen is in the range of 0.001 to 0.20% by mass, or 0.01 to 0.20% by mass, typically 0.02 to 0.20% by mass, relative to the mass of the inorganic particles.

[0061] Examples of the above-mentioned amines include aliphatic amines and aromatic amines, but aliphatic amines are preferably used. At least one amine selected from the group consisting of primary, secondary, and tertiary amines having 1 to 10 carbon atoms can be used. These amines are water-soluble and are at least one amine selected from the group consisting of primary, secondary, and tertiary amines having 1 to 10 carbon atoms.

[0062] Examples of primary amines include monomethylamine, monoethylamine, monopropylamine, monoisopropylamine, monobutylamine, monoisobutylamine, monosec-butylamine, monotert-butylamine, monomethanolamine, monoethanolamine, monopropanolamine, monoisopropanolamine, monobutanolamine, monoisobutanolamine, monosec-butanolamine, and monotert-butanolamine. Examples of secondary amines include dimethylamine, diethylamine, dipropylamine, diisopropylamine, N-methylethylamine, N-ethylisobutylamine, dimethanolamine, diethanolamine, dipropanolamine, diisopropanolamine, N-methanolethylamine, N-methylethanolamine, N-ethanolisobutylamine, and N-ethylisobutanolamine. Examples of tertiary amines include trimethylamine, triethylamine, tripropylamine, triisopropylamine, diisopropylethylamine, tributylamine, triisobutylamine, trisecbutylamine, tritertbutylamine, trimethanolamine, triethanolamine, tripropanolamine, triisopropanolamine, tributanolamine, triisobutanolamine, trisecbutanolamine, tritertbutanolamine, tripentylamine, ethyl 3-(dimethylamino)acrylate, ethyl 2-(dimethylamino)acrylate, ethyl 2-(dimethylamino)methacrylate, ethyl 2-(diethylamino)acrylate, and ethyl 2-(diethylamino)methacrylate.

[0063] Furthermore, the inorganic particle-dispersed organosol according to the present invention can have its pH adjusted from acidic to alkaline. The pH can be set to less than 7 on the acidic side and 7 or more and 13 or less on the alkaline side. Adjustment to acidity is performed by adding an inorganic acid or organic acid, and adjustment to alkalinity is performed by adding an inorganic base or organic base (for example, the basic compound mentioned above).

[0064] Furthermore, the pH of an inorganic particle dispersion organosol can be determined by the pH obtained when an organic solvent sol is mixed with an equal mass of pure water in a 1:1 ratio. pH measurement is performed in the form of a sol of an organic solvent that can be mixed with water. If the solvent is later replaced with a hydrophobic organic solvent, the pH should be measured beforehand at the stage of a hydrophilic organic solvent sol such as methanol, or by adding a hydrophilic organic solvent to the hydrophobic solvent sol and then measuring the pH. For example, when a hydrophilic organic solvent such as methanol sol and propylene glycol monomethyl ether sol is the dispersion medium, the pH is measured in a solution obtained by mixing the sol with pure water in a 1:1 mass ratio. Also, when a hydrophobic organic solvent such as methyl ethyl ketone sol is the dispersion medium, the pH can be measured in a solution obtained by mixing pure water, methanol, and methyl ethyl ketone sol in a 1:1:1 mass ratio.

[0065] [Method for producing inorganic particle-dispersed organosol] The inorganic particle-dispersed organosol of the present invention is produced by a step of replacing the dispersed water of an inorganic particle aqueous dispersion sol containing four-coordinate aluminum atom-containing inorganic particles and having a pH of 5 to 12 with an organic solvent by ultrafiltration, heating under reduced pressure, or heating under normal pressure.

[0066] First, an inorganic particle aqueous dispersion sol containing four-coordinate aluminum atom-containing inorganic particles and having a pH of 5 to 12 can be manufactured by the following steps: (i) Step: A step of preparing an aqueous sol containing inorganic particles; (ii) Step: Adding an aluminum compound to the aqueous sol prepared in step (i) per gram of inorganic particles, Al ２ O ３ The process involves adding an amount equivalent to 0.0001 to 0.5 g, holding it at 40 to 260°C for 0.1 to 24 hours, and obtaining an aqueous dispersion sol of aluminum atom-containing inorganic particles.

[0067] (i) In step (i), first, an aqueous sol containing inorganic particles (also called an aqueous sol of inorganic particles) is prepared. The "inorganic particles" prepared in step (i) are, so to speak, raw material inorganic particles, and are distinct from the aluminum atom-containing inorganic particles mentioned above, that is, inorganic particles that do not contain aluminum atoms (however, the presence of aluminum atoms at the impurity level is permissible). It is desirable that the aqueous sol containing these raw material inorganic particles has a low TN amount, and for example, an aqueous sol can be used in which the TN amount is 3% by mass or less, 2% by mass or less, or 1% by mass or less relative to the mass of the inorganic particles. If the raw material inorganic particles are hollow silica particles, hollow particles with a space inside the outer shell can be obtained by first forming an outer shell mainly composed of silica on the surface of a part corresponding to a core called a template in an aqueous dispersion medium, and then removing the part corresponding to the core (template). The above template can be made using an organic material (for example, hydrophilic organic resin particles such as polyethylene glycol, polystyrene, or polyester) or an inorganic material (for example, hydrophilic inorganic compound particles such as calcium carbonate or sodium aluminate).

[0068] (i) As the aqueous sol containing inorganic particles of the raw materials prepared in the process, any of a non-hydrothermally treated inorganic particle aqueous sol, a hydrothermally treated inorganic particle aqueous sol, or a mixture thereof can be used. The non-hydrothermally treated inorganic particle aqueous sol is an aqueous sol of inorganic particles treated via a heating temperature of less than 100°C, for example, less than 20°C to less than 100°C, or less than 40°C to less than 100°C, or less than 50°C to less than 100°C in an aqueous medium. Also, the hydrothermally treated inorganic particle aqueous sol is an aqueous sol of inorganic particles treated via a heating temperature of 100°C to 240°C, or 110°C to 240°C in an aqueous medium. The above-mentioned inorganic particle aqueous sol of the raw materials (non-hydrothermally treated inorganic particle aqueous sol, hydrothermally treated inorganic particle aqueous sol, or a mixture thereof) can be in a form in which the inorganic particles of the raw materials in the aqueous sol contain aluminum atoms in the process (ii) described later. For example, when the inorganic particles are hollow silica particles, an aluminosilicate site can be formed on the outer shell of the hollow silica particles. Since the aluminosilicate site may hold an alkali metal, in the measurement by the dissolution method using the above-mentioned hydrofluoric acid aqueous solution, aluminum atoms are Al ２ O ３ It is possible to select the inorganic particle aqueous sol of the raw materials so that they can be present at a ratio of 120 to 50,000 ppm in terms of conversion (relative to the mass of the inorganic matter).

[0069] (ii) The process is a process of adding an aluminum compound to the inorganic particle aqueous sol (of the raw materials) prepared in the above (i) process, heating and holding to obtain an aluminum atom-containing inorganic particle aqueous dispersion sol. By this process, an aluminum compound is allowed to act (so-called impregnation) from the outside of the inorganic particles of the raw materials, and aluminum atoms are made to exist on the surface of the inorganic particles, that is, an aluminosilicate site is formed at least on the surface of the particles.

[0070] (Raw materials) When applying (impregnating) aluminum compounds from the outside after the formation of inorganic particles, there are two methods: one in which the inorganic particles are pre-treated with hydrothermal energy to improve the density of the surface layer (outer shell in the case of hollow particles) of the inorganic particles, and then impregnated with aluminum compounds by heat treatment; and another in which inorganic particles that have not been pre-treated with hydrothermal energy are impregnated with aluminum compounds by heat treatment. In both the former and latter methods, the aluminum atoms (Al) present throughout the inorganic particles are measured by the dissolution method using the hydrofluoric acid aqueous solution as described above. ２ O ３ It is preferable to impregnate the aluminum compound such that the amount of (converted) present is in the specific proportion mentioned above.

[0071] (ii) The aluminum compound used in the step is Al per gram of inorganic particles in the inorganic particle aqueous sol. ２ O ３ The amount that can be added is in the range of 0.0001 to 0.5 g, 0.001 to 0.1 g, or 0.001 to 0.05 g in conversion. The heating temperature in step (ii) is 40 to 260°C, 50 to 260°C, or 60 to 240°C. The heating temperature can be 40 to less than 100°C, 50 to less than 100°C, or 60 to less than 100°C in the case of non-hydrothermal treatment, and 100 to 260°C, or 150 to 240°C in the case of hydrothermal treatment. The heating time in step (ii) can be in the range of 0.1 to 48 hours, 0.1 to 24 hours, 0.1 to 10 hours, or 1 to 10 hours. Furthermore, the impregnation of the aluminum compound into the inorganic particles and the formation of aluminosilicate to achieve the desired amount of aluminum atoms depends on the processing temperature in step (ii), and it is essential to perform the heat treatment within the above temperature range.

[0072] Specific examples of the above-mentioned aluminum compounds include at least one aluminum compound selected from the group consisting of aluminates, aluminum alkoxides, and their hydrolysates. Examples of aluminates include sodium aluminate, potassium aluminate, calcium aluminate, magnesium aluminate, ammonium aluminate, and aluminate amine salts. Examples of aluminum alkoxides include aluminum isopropoxide and aluminum butoxide. Among these, aluminates such as sodium aluminate can be preferably used.

[0073] The above aluminum compound can be added to the inorganic particle aqueous sol in solid or aqueous form, and it is preferable to add it in aqueous form. When the above aluminum compound is added to the inorganic particle aqueous sol in aqueous form, the concentration of the aluminum compound in the aqueous solution can be in the range of 0.01 to 20% by mass, 0.1 to 10% by mass, or 0.5 to 5% by mass. The addition of the above aluminum compound can be carried out under stirring of the inorganic particle aqueous sol. This addition can be completed before heating, added before heating and completed during heating, or added throughout the entire heating time. Furthermore, the aqueous dispersion sol produced by including steps (i) and (ii) above is obtained as a sol whose pH is adjusted to the range of 5 to 12 by the addition of the above aluminum compound. Furthermore, the aluminum atom-containing inorganic particles of the obtained aqueous dispersion sol are ２７ Using Al-NMR measurement, the coordination pattern of aluminum atoms in the particles can be confirmed by the same procedure as described above for organosols (however, acetylacetone may be omitted).

[0074] The aqueous dispersion sol (aluminum atom-containing inorganic particle aqueous sol) obtained in this way, containing four-coordinate aluminum atom-containing inorganic particles and having a pH of 5 to 12, can be subjected to a step of replacing the dispersed water with an organic solvent by ultrafiltration, heating under reduced pressure, or heating under normal pressure. The organic solvent can be the organic solvents mentioned above. The reduced pressure conditions can be about 10 to 600 Torr, and the heating conditions can be about 30 to 200°C. When converting from an aqueous sol to a hydrophobic organic solvent sol, the aqueous medium can be first solvent-substituted with a hydrophilic organic solvent (such as alcohol), and then further solvent-substituted with a hydrophobic organic solvent, and some water may remain during this process. In this case, for example, the residual water in the alcohol sol of four-coordinate aluminum atom-containing inorganic particles can be about 0.1 to 3.0% by mass, or about 0.1 to 1.0% by mass. Also, for example, the residual water in the organic solvent sol of aluminum atom-containing inorganic particles (where the dispersion medium is an organic solvent other than alcohol) can be about 0.01 to 0.5% by mass.

[0075] Before and / or after the substitution step with the organic solvent, the surface of the aluminum atom-containing hollow silica particles may be treated with at least one silane compound selected from the group consisting of compounds represented by formulas (1) and (2). This step can be performed by adding the aforementioned silane compound to an aqueous sol or organic solvent sol containing four-coordinate aluminum atom-containing inorganic particles, and then heating and stirring at 10°C to 95°C for about 0.1 to 20 hours. This step of adding the silane compound and heating and stirring may be performed multiple times.

[0076] Furthermore, the process may include adding a polymerization inhibitor to the aqueous dispersion sol or organosol containing four-coordinate aluminum atom-containing inorganic particles before, simultaneously with, or after the addition of the silane compound and before heating and stirring. This process suppresses the polymerization of the silane compound having polymerizable groups such as (meth)acryloyl groups, making it possible to obtain an inorganic particle dispersion organosol that is less susceptible to deterioration over time and can be stored for a long period of time. Examples of polymerization inhibitors include p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, benzoquinone, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine salts (ammonium salts, cerium salts, etc.), nitrosophenylhydroxyamine aluminum salts, diphenylnitrosamines, etc., with p-methoxyphenol being a prime example. The polymerization inhibitor content can be 0.00001 to 5% by mass, 0.0001 to 5% by mass, 0.001 to 5% by mass, 0.001 to 5% by mass, more preferably 0.00001 to 1% by mass, and even more preferably 0.00001 to 0.5% by mass, relative to the mass of inorganic particles. The polymerization inhibitor may be of one type or two or more types. If two or more types are used, it is preferable that the total amount falls within the above range.

[0077] Furthermore, the process may include adding a basic compound before or after the silane compound addition and heating / stirring step to increase the pH by 0.1 to 7. The basic compound to be added may be either an organic base or an inorganic base, and those listed in the above-mentioned [basic compounds] can be used.

[0078] The present invention provides a method for producing an inorganic particle-dispersed organosol, but is not particularly limited to the method itself, except that it includes the essential step of replacing the dispersion medium (dispersed water) of the aforementioned aqueous dispersion sol with an organic solvent by ultrafiltration, heating under reduced pressure, or heating under normal pressure. For example, the step of adding a silane compound and heating and stirring (a step of treating the surface of aluminum atom-containing hollow silica particles with a silane compound) and the step of adding a basic compound (a pH increase step) are optional, and the organic solvent replacement step, the silane compound addition and heating and stirring step, and the pH increase step can be performed in any order and in combination multiple times. For example, the step of replacing the dispersed water with an organic solvent by ultrafiltration / heating under reduced pressure / heating under normal pressure may be performed after the ion exchange step and / or after the silane compound addition and heating and stirring step and / or after the pH increase step. Furthermore, after the pH increase step, the silane compound addition and heating and stirring step may be performed again, followed by the step of replacing the dispersed water with an organic solvent by ultrafiltration / heating under reduced pressure / heating under normal pressure. However, the invention is not limited to combinations of these steps. Furthermore, when using multiple types of inorganic particles, such as hollow silica particles and solid silica particles, the timing of their addition can be simultaneous or staggered. For example, a different type of particle can be added after the silane compound addition and heating / stirring process, and heating and stirring can be optionally carried out at 10°C to 95°C for approximately 0.1 to 20 hours.

[0079] Furthermore, the process may include a step of performing at least one type of ion exchange, selected from cation exchange or anion exchange, on the organosol containing four-coordinate aluminum atom-containing inorganic particles, particularly a step of cation exchange. This step can be performed at any stage after the solvent of the aforementioned aqueous dispersion sol has been replaced with an organic solvent to form an organosol, and may be performed multiple times. This step removes impurity ions such as aluminum compound ions, sulfate ions, sodium ions, and ammonium ions eluted from the aluminum atom-containing inorganic particles, and increases the amount of silane compound bound to the surface of the inorganic particles, allowing for stable dispersion in the organosol. This step can be performed using commercially available cation exchange resins and anion exchange resins.

[0080] Furthermore, after the aforementioned substitution step of dispersed water into an organic solvent by ultrafiltration / heating under reduced pressure / heating under normal pressure, a step of substitution with a solvent with a lower dielectric constant may be performed. In this case, the substitution step can be carried out by ultrafiltration / heating under reduced pressure / heating under normal pressure as described above. Examples of solvents with a lower dielectric constant include organic solvents from the aforementioned organic solvents whose relative dielectric constant at 20°C is 1 to 20, and such solvents can be treated as highly hydrophobic organic solvents. Typical examples include methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclopentanone (CPN), cyclohexanone (CHN), dibutyl ketone, ethyl acetate, n-butyl acetate, toluene, and xylene.

[0081] The organic solvent dispersion sol of inorganic particles using the aforementioned organic solvent as the dispersion medium can be modified by performing a step of substituting the dispersion medium with the aforementioned reactive monomer or polymer to obtain an inorganic particle organosol in which the dispersion medium is the aforementioned reactive monomer or polymer. For example, the reactive monomer or polymer may be added to and mixed with the organic solvent dispersion sol of inorganic particles, and then the organic solvent may be removed or reduced by distillation or heating under reduced pressure as needed. The organic solvent may remain after this operation. Alternatively, the reactive monomer or polymer may be dissolved in the organic solvent beforehand, and then added and mixed with the organic solvent dispersion sol of inorganic particles, and then the organic solvent may be removed or reduced by distillation or heating under reduced pressure as needed (the organic solvent may remain after this operation). Furthermore, when adding the reactive monomer or polymer, the aforementioned polymerization inhibitor (such as p-methoxyphenol) may be incorporated into the sol. In other words, the inorganic particle organosol according to the present invention may also contain a polymerization inhibitor.

[0082] The present invention also includes resin compositions comprising the above-mentioned four-coordinate aluminum atom-containing inorganic particles and the above-mentioned polymer. That is, the amount of aluminum atoms present in the total amount of inorganic particles is Al ２ O ３The present invention relates to a resin composition comprising inorganic particles containing four-coordinate aluminum atoms in an amount of 100 to 50,000 ppm relative to the mass of the inorganic particles, and a polymer containing at least one monomer selected from the group consisting of (meth)acrylic compounds, polyfunctional (meth)acrylates, allyl compounds, isocyanate compounds, isothiocyanate compounds, epoxy compounds, diamine-containing compounds, diol-containing compounds, dicarboxylic acid-containing compounds, disulfyl chloride-containing compounds, dithiol-containing compounds, disulfide-containing compounds, divinyl-containing compounds, diallyl-containing compounds, styrene, tetracarboxylic anhydride, bismaleimide, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, and propylene as a monomer component. The resin composition may also include the aforementioned anions and organic solvents. Furthermore, a film-forming composition can be one embodiment (one application) of the resin composition that is the subject of the present invention. In the resin composition or film-forming composition, the amount of inorganic particles containing four-coordinate aluminum atoms can be, for example, 1% to 90% by mass of the total solid content (100% by mass), and the amount of polymer can be, for example, 10% to 99% by mass. The solid content in the film-forming composition refers to all components other than the solvent, and can be calculated from the residue obtained by, for example, heating the resin composition at a temperature of about 200 to 300°C to remove the solvent. As the polymer, for example, a thermosetting or photocurable resin (curable resin) can be selected. Furthermore, the resin composition or film-forming composition of the present invention may further contain curing agents such as amine-based curing agents, acid anhydride-based curing agents, radical-generating curing agents (thermal radical generators, photoradical generators), acid-generating curing agents (thermal acid generators or photoacid generators), and base generators (thermal base generators, photobase generators). Furthermore, the resin composition or film-forming composition of the present invention may contain conventional additives as needed.Examples of such additives include surfactants (leveling agents), pigments, colorants, thickeners, adhesion promoters, sensitizers, defoamers, coating properties improvers, lubricants, stabilizers (antioxidants, heat stabilizers, light stabilizers, etc.), plasticizers, dissolution accelerators, fillers, antistatic agents, and development inhibitors (diazonaphthoquinone, etc.). These additives may be used individually or in combination of two or more.

[0083] The resin composition can be applied to or filled into a substrate and cured by heating, light irradiation, or a combination thereof. Furthermore, when the resin composition is in the form of a film-forming composition, a photocurable film-forming composition can be applied to a substrate to form a coating film, and the coating film can be cured by light irradiation to obtain a coating (cured body). Heating can also be performed before or after light irradiation. Examples of application methods for the film-forming composition include flow coating, spin coating, spray coating, screen printing, casting, bar coating, curtain coating, roll coating, gravure coating, dipping, and slitting. 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 for photoresists, it can be approximately 0.05 to 10 μm (particularly 0.1 to 5 μm); when used for printed circuit boards, it can be approximately 5 μm to 5 mm (particularly 100 to 1 mm); and when used for optical thin films, it can be approximately 0.1 to 100 μm (particularly 0.3 to 50 μm). When obtaining a transparent coating, it is desirable that the visible light transmittance of the coating be 80% or higher, or 90% or higher, typically 90% to 96%.

[0084] [Applicable to] The inorganic particle-dispersed organosol according to the present invention, or a resin composition comprising the four-coordinate aluminum atom-containing inorganic particles and the polymer, is preferably used for applications as a material for anti-reflective coatings.

[0085] For example, thermosetting materials and photocuring materials using the inorganic particle-dispersed organosol of the present invention, or a resin composition containing the four-coordinate aluminum atom-containing inorganic particles and the polymer, have characteristics such as transparency and low curing shrinkage, and can be used for coating and bonding electronic components, optical components (anti-reflective coatings), and precision mechanical components.

[0086] 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.

[0087] The silica aqueous sol, silane compound, organic solvent, and polymerization inhibitor used as raw materials in the examples and comparative examples are as follows.

[0088] (Raw material: hollow silica aqueous sol) ・Water-dispersed silica sol A: Product name HKT-A20-40D-3 (manufactured by Ningbo Dilato), water-dispersed silica sol of hollow silica particles, values ​​from the physical property evaluation described later: Average primary particle diameter 38 nm by TEM, outer shell thickness 5 nm, specific surface area 118 m² by BET method ２ / g, refractive index 1.3, silanol group number density on the surface of hollow silica particles 1.6 / nm ２ , Average particle size by DLS method: 47 nm, Amount of aluminum atoms present throughout hollow silica particles: Al ２ O ３ Converted to 1 ppm SiO ２ Less than TN 0.5 mass% / SiO ２ • Water-dispersed silica sol B: Product name HKT-A20-40D-4 (manufactured by Ningbo Dilato), water-dispersed silica sol of hollow silica particles, values ​​from the physical property evaluation described below: Average primary particle diameter 40 nm by TEM, outer shell thickness 5 nm, specific surface area 125 m² by BET method. ２ / g, refractive index 1.3, silanol group number density on the surface of hollow silica particles 2.2 / nm ２ , Average particle size by DLS method: 52 nm, Amount of aluminum atoms present throughout hollow silica particles: Al ２ O ３ Converted to 1 ppm / SiO ２ Less than TN 0.5 mass% / SiO ２• Water-dispersible silica sol C: Product name HKT-A20-40D-5 (manufactured by Ningbo Dilato), water-dispersible silica sol of hollow silica particles, values ​​from the physical property evaluation described below: Average primary particle diameter 38 nm by TEM, outer shell thickness 5 nm, specific surface area 118 m² by BET method. ２ / g, refractive index 1.3, silanol group number density on the surface of hollow silica particles 1.1 / nm ２ , Average particle size by DLS method: 50 nm, Amount of aluminum atoms present throughout hollow silica particles: Al ２ O ３ Converted to 1 ppm / SiO ２ Less than TN 2.5 mass% / SiO ２ • Water-dispersible silica sol D: Product name HKT-A20-70D (manufactured by Ningbo Dilato), water-dispersible silica sol of hollow silica particles. Physical properties as determined by the physical property evaluation described below: Average primary particle diameter 65 nm, outer shell thickness 8 nm, specific surface area 89 m² by BET method. ２ / g, refractive index 1.2, average particle diameter by DLS method: 87 nm, amount of aluminum atoms present in the entire hollow silica particle: Al ２ O ３ Converted to 1 ppm / SiO ２ Less than TN 0.1 mass% / SiO ２ • Water-dispersible silica sol E: Product name HKT-A20-48D (manufactured by Ningbo Dilato), water-dispersible silica sol of hollow silica particles. Physical properties as determined by the physical property evaluation described below: Average primary particle diameter 48 nm, outer shell thickness 7 nm, specific surface area 105 m² by BET method. ２ / g, refractive index 1.3, average particle diameter by DLS method: 63 nm, amount of aluminum atoms present throughout hollow silica particles: Al ２ O ３ Converted to 1 ppm / SiO ２ Less than TN 0.1 mass% / SiO ２ • Water-dispersible silica sol F: Product name HKT-A20-50D (manufactured by Ningbo Dilato), water-dispersible silica sol of hollow silica particles. Physical properties as determined by the physical property evaluation described below: Average primary particle diameter 55 nm, outer shell thickness 7 nm, specific surface area 104 m² by BET method. ２ / g, refractive index 1.2, average particle diameter by DLS method: 69 nm, amount of aluminum atoms present in the entire hollow silica particle: Al ２ O ３ Converted to 1 ppm / SiO ２ Less than TN 0.1 mass% / SiO ２

[0089] (Raw material: solid silica aqueous sol) ・Water-dispersed silica sol G: ST-OXS (manufactured by Nissan Chemical Corporation), a water-dispersed silica sol of solid silica particles. Values ​​from the physical property evaluation described later: silica particle concentration 10.4% by mass, pH 2.8, average primary particle diameter 5 nm by TEM, specific surface area 496 m² by BET method ２ / g, the amount of aluminum atoms present in the entire solid silica particle is Al ２ O ３ Converted to 1700 ppm / SiO ２ Refractive index 1.4, TN 0.1 mass% / SiO ２ less than

[0090] (Silane compounds (surface modifiers, silanes manufactured by Shin-Etsu Chemical Co., Ltd.)) ・AcPS: 3-acryloxypropyltrimethoxysilane ・MPS: 3-methacryloxypropyltrimethoxysilane ・PTMS: phenyltrimethoxysilane ・MPDMS: dimethoxymethylphenylsilane (Tokyo Chemical Industries, Ltd.) ・HMDS: hexamethyldisiloxane (Tokyo Chemical Industries, Ltd.)

[0091] (Organic solvents) ・MeOH: Methanol (manufactured by Kanto Chemical Co., Ltd., Kagoshima Grade 1) ・MEK: Methyl ethyl ketone (manufactured by Kanto Chemical Co., Ltd., Kagoshima Grade 1) ・AN: Acetone (manufactured by Kanto Chemical Co., Ltd., Special Grade) ・HX: Hexane (manufactured by Kanto Chemical Co., Ltd., Special Grade) ・PGME: Propylene glycol monomethyl ether ・MIBK: Methyl isobutyl ketone (manufactured by Kanto Chemical Co., Ltd., Kagoshima Grade 1) ・PGMEA: Propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd., Kagoshima Special Grade) ・MMB: 3-Methyl-3-methoxy-1-butanol (manufactured by Junsei Chemical Co., Ltd., Special Grade) ・n-BtOH: n-butanol (manufactured by Kanto Chemical Co., Ltd., Kagoshima Grade 1)

[0092] (Polymerization inhibitor) MEHQ: p-methoxyphenol (manufactured by Kawaguchi Chemical Industry Co., Ltd., trade name: MQ) (Basic compound) DiPEA: N,N-diisopropylethylamine

[0093] (Equipment used for hollow silica sol production) Cation exchange resin: H-type Amberlite (product name) IR-120B, harmonic mean diameter 0.6-0.8 mm, manufactured by Organo Corporation Mix rotor: MIX-ROTAR MR-5 (product name), manufactured by AS ONE Corporation

[0094] The physical properties of the aqueous silica sol, the organo-silica sols prepared in the examples and comparative examples, and the silica sols and silica particles during the manufacturing process of the silica sol were evaluated according to the following method.

[0095] (Measurement of silica particle concentration in silica sol) The silica particle concentration of water-dispersed silica sol and organic solvent-dispersed silica sol was calculated by placing the silica sol in a crucible, removing the solvent by heating on a hot plate, calcining at 1000°C, and weighing the resulting calcined residue. As will be described later, the sols prepared in each example contain sulfuric acid, etc., but after the calcination, organic components such as amines are almost completely eliminated by volatilization / thermal decomposition, and the amount of these added, including sulfuric acid, is very small, so the concentration calculated by the above method can be treated as the concentration of silica particles in the silica sol.

[0096] (pH Measurement of Silica Sol) The pH of water-dispersed silica sol was measured at 20°C using a pH meter (manufactured by Toa DKK Co., Ltd., product name: MM-43X). The pH of organic solvent-dispersed silica sol was measured at 20°C using a pH meter (manufactured by Toa DKK Co., Ltd., product name: MM-43X) if the particles were not surface-treated with silane, by mixing the organic solvent-dispersed silica sol with pure water in a 1:1 mass ratio, and if the particles were surface-treated with silane, by mixing the organic solvent-dispersed silica sol, MeOH, and pure water in a 1:1:1 mass ratio. When measuring the solution of organic solvent-dispersed silica sol and pure water mixed in a 1:1 mass ratio, it is also expressed as pH(1+1), and when measuring the solution of organic solvent-dispersed silica sol, MeOH, and pure water mixed in a 1:1:1 mass ratio, it is also expressed as pH(1+1+1).

[0097] (Viscosity measurement of silica sol) The viscosity of water-dispersed silica sol, organic solvent-dispersed silica sol, or silica sol in the manufacturing process of said silica sol was measured at 20°C using an Ostwald viscometer (manufactured by Shibata Scientific Co., Ltd.).

[0098] (Specific surface area value (S) by BET method (nitrogen gas adsorption method) Ｎ２ ) Measurement) Specific surface area value (S) of silica particles in aqueous dispersion silica sol by nitrogen gas adsorption method Ｎ２ ) After removing water-soluble cations from the aqueous dispersion silica sol with an H-type cation exchange resin (manufactured by Dow Chemical, trade name: Amberlite IR-120B), the silica sol is dried at 290°C to prepare the measurement sample, and this is measured using a specific surface area analyzer by nitrogen gas adsorption, trade name Monosorb (manufactured by Quantachrome Instruments Japan LLC), N ２ A mixed gas of 30% nitrogen and 70% helium (He) was used as the carrier gas, and measurements were taken using the B.E.T. single-point method. Specific surface area (S) of silica particles in an organic solvent-dispersed silica sol was determined by nitrogen gas adsorption. Ｎ２ The carbon content (Cp) was measured using the B.E.T. one-point method described above, with the measurement sample (silica particles (powder) heated at 150°C) obtained in the measurement of the carbon content (Cp) by elemental analysis of silica particles described later.

[0099] (Measurement of average particle diameter by DLS method (average particle diameter by dynamic light scattering method)) The average particle diameter by DLS method (average particle diameter by dynamic light scattering method: Z average particle diameter) was measured using a dynamic light scattering particle diameter analyzer (Malvern Panalogical, product name: Zetasizer Nano). 0.1 g of the target silica sol was placed in a glass cell with an optical path length of 10 mm, and the same solvent as the dispersion medium of the silica sol was added to obtain a silica sol in which the silica particle concentration was adjusted so that the count rate when the attenuator was set to 7 was 200 to 400 kcps. For example, in Example 1 described later, MeOH was added, and in Example 2, PGME was added to obtain a silica sol in which the silica particle concentration was adjusted so that the count rate when the attenuator was set to 7 was 200 to 400 kcps. The prepared silica sol was placed in the cell, and the liquid level was adjusted so that it was approximately 1 cm above the bottom of the cell. The particle size of the silica sol was then measured using the dynamic light scattering method with the attenuator 7.

[0100] (Measurement of average primary particle diameter by TEM (transmission electron microscope)) Particles in silica sol were photographed using a transmission electron microscope (product name JEM-F200, manufactured by JEOL Ltd.), and 300 arbitrarily selected particles were binarized using an automated image processing and analysis system (product name LUZEX' AP, manufactured by Nireco Corporation). The diameter obtained by converting the projected area to a circular value was measured as the average primary particle diameter (HEYWOOD diameter).

[0101] (Measurement / Dissolution Method of Aluminum Amount Present in the Entire Silica Particle) The precisely weighed silica sol was dried, and 250 mg of the resulting particles were dissolved in 2.5 ml of nitric acid (manufactured by Kanto Chemical Co., Ltd., trade name: Nitric Acid 1.38, purity 60.0%) and 2.5 ml of 38% hydrofluoric acid (manufactured by Tama Chemical Industry 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-OES analyzer (manufactured by Rigaku Corporation, trade name: CIROS120 EOP), and the amount of aluminum present in the entire silica particle was determined to be Al ２ O ３ The amount relative to the mass of silica particles (Al ２ O ３ (ppm) / SiO ２ ) was requested.

[0102] (Measurement of Surface Charge of Silica Particles) Silica sol was added to 10 mL of methanol to obtain a silica particle concentration of 0.5% by mass, and this was used as the measurement sample. Using a particle charge meter (Voyt Turbo Co., Ltd., product name PCD-06), a 0.001 mol / liter (N / 1000) DADMAC solution (Voyt Turbo Co., Ltd.) was used as the cation standard titrator, and the titration value was measured until the flow potential of the measurement sample became zero. The obtained titration value was divided by the amount of silica particles contained in the measurement sample to obtain the surface charge amount (μeq / g) per gram of silica particles. Note that DADMAC refers to poly(diallyldimethylammonium chloride).

[0103] (Measurement of carbon content (Cp) by elemental analysis of silica particles) 4 ml of silica sol obtained in the example was placed in a 42 ml pear-shaped sedimentation tube (manufactured by Thermo Fisher Scientifics, trade name: Nalgene Oak Ridge), 4 ml of MEK and 20 ml of HX were added, and the mixture was allowed to stand for 5 minutes to induce turbidity, separation, or precipitation due to aggregation. Then, the mixture was centrifuged using a centrifuge (manufactured by Tommy Seikou Co., Ltd., trade name: High-speed refrigerated centrifuge Suprema 21) (temperature: 5°C, rotation speed: 20000 rpm, time: 30 minutes), and the supernatant was removed. Then, 4 ml of acetone was added, and the precipitate obtained by centrifugation was redissolved in a test tube mixer (AS ONE Corporation, trade name: MVM-10), and then 20 ml of HX was added. After that, the mixture was centrifuged, and the supernatant was removed. Subsequently, 4 ml of acetone was added, and the precipitate obtained by centrifugation was redissolved in a test tube mixer, after which 20 ml of HX was added. After centrifugation, the supernatant was removed. The obtained precipitate (mixture) was vacuum dried (temperature: 60°C, pressure: -0.1 MPa), and the resulting powder was ground in a mortar for 10 minutes to obtain silica particles (powder). The obtained silica particles were heated at 150°C to remove adsorbed water and used as the measurement sample. The carbon content (Cp: mass%) of the silica particles (measurement sample) was measured using an elemental analyzer (PerkinElmer, model name: Elemental Analyzer 2400II).

[0104] (Measurement of carbon content and unbound silane content (Ct) of silica particles) The silica sol solvent obtained in the example was heated at 150°C to remove the dispersion medium and adsorbed water, and the measurement sample was prepared. The measurement sample was measured using an elemental analyzer (PerkinElmer, model name: Elemental analyzer 2400II), and the total amount (Ct: mass%) of carbon content of silica particles in the measurement sample (Cp above) and unbound carbon content not contained in the particles (so to speak, unbound carbon) (derived from the silane compound, which is a surface modifier, also called unbound silane content) was determined.

[0105] (Unit surface area of ​​silica particles (unit: nm) ２ Measurement of the amount (number) of bonded silanes per unit area of ​​silica particles (unit: nm) ２ The amount of bound silane (number of particles) per 1 nm was calculated based on the following formula, using the amount of silane compound added (number of particles) during the preparation of the silica particle dispersion sol in an organic solvent, and the measurement results of Cp and Ct mentioned above. Bound silane amount (number of particles / nm) ２ ) = Silane addition amount (particles) × Cp / Ct Note that the surface area of ​​silica particles is the specific surface area value (S) obtained by the nitrogen gas adsorption method described above. Ｎ２ ) was used.

[0106] (Measurement of the refractive index of silica particles) The following procedures 1) to 3) were followed for measurement. 1) Preparation of aqueous sol varnish containing silica particles 20.00 g of 3-glycidoxypropyltrimethoxysilane (Momentive, trade name SILQUEST A-187T) was weighed into a plastic container, and 18.57 g of methanol and 4.57 g of 0.01 N hydrochloric acid aqueous solution were added thereto, and the mixture was stirred at room temperature for 5 hours. The previously prepared 2,4-aluminum pentanedione (Al(acac) ３ ) methanol solution (10% by mass Al(acac) ３6.00 g of ) was added as a curing agent and stirred for 10 minutes to prepare a partial hydrolysate of 3-glycidoxypropyltrimethoxysilane (GPS) (concentration: 43% by mass). 0.25 g of the prepared partial hydrolysate of GPS, water, methanol, and a methanol solution of a leveling agent (DOWSIL trade name L-7604) (10% by mass L-7604) was weighed into a brown bottle and stirred at room temperature for 30 minutes to prepare a silica particle aqueous sol-containing varnish (silica particle concentration: 4% by mass, silica particle content: 50, 100, or 150). 2) Preparation of silica particle-containing film The silica particle aqueous sol-containing varnish obtained in 1) (amount of silica particles: 50 phr, 100 phr, or 150 phr) is UV-O ３ Approximately 1 mL was dropped onto a processed Si substrate, and a spin coater (Mikasa Corporation, product name Opticoat MS-B100) was used to uniformly spread the film on the Si substrate under the following conditions: increasing to 200 rpm in 2 seconds, 200 rpm x 10 seconds, further increasing to 800 rpm in 2 seconds, 800 rpm x 5 seconds, and then decreasing to 0 rpm in 5 seconds. Subsequently, the film was baked on a hot plate at 80°C for 5 minutes and then heat-treated in an oven at 120°C for 1 hour to prepare a silica particle-containing film (silica particle content: 50 phr, 100 phr, or 150 phr). 3) Measurement of refractive index of silica particle-containing film and calculation of refractive index of silica particles The refractive index of the silica particle-containing film obtained in 2) (silica particle content: 50 phr, 100 phr, or 150 phr) was measured using an ellipsometer (product name: Multi-incidence angle spectroscopic ellipsometer VASE, manufactured by J.A. Woolam Japan Co., Ltd.). Separately, the refractive index of a film without silica particles, similarly prepared using only the partial hydrolysate of GPS, was also measured. The refractive index of the measured-down-to-one-silica-containing film was plotted against the silica particle content and extrapolated so that the silica particle content was 100% by mass to determine the refractive index of the silica particles.

[0107] (Measurement of anion content in organosilica sol (hereinafter, anion content in system)) 20 mg of the target organosilica sol was mixed with 0.1 g of methanol, then 0.9 g of 10 mM NaOH aqueous solution was added and mixed. The resulting solution was measured by ion chromatography using an anion analyzer (product name Dionex ICS-2100, manufactured by Thermo Scientific), and the anion content in system (SO ４ － , Cl － The (ppm) value was calculated.

[0108] (Measurement of moisture content) The moisture content of the target sol was measured using the Karl Fischer titration method with a Karl Fischer moisture meter (manufactured by Kyoto Electronics Manufacturing Co., Ltd., product name: MKA-610).

[0109] (Measurement of methanol (MeOH) content (performed in sols other than methanol dispersion sol and aqueous dispersion sol)) The amount of methanol (MeOH) contained in the target sol was measured using gas chromatography (Shimadzu Corporation, product name: GC-2014s) under the following conditions. Column: 3 mm x 1 m glass column Packing material: Polar Pack Q Column temperature: 130 to 230 °C (heating increase of 8 °C / min) Carrier: N ２ 40 mL / min, Detector: FID, Injection volume: 1 μL, Internal standard: Acetonitrile.

[0110] (Method for measuring TN) The nitrogen content (TN amount) contained in the target sol was measured using a trace nitrogen analyzer (TN-2100V, manufactured by Mitsubishi Chemical Analytech Co., Ltd. (now Nitto Seiko Analytech Co., Ltd.)).

[0111] (Measurement of the presence or absence of Al peaks other than 4-coordinate Al peaks (6-coordinate Al peaks) in organosols) Add 1000 ppm by mass of acetylacetone to the target organosol and stir. ２７Al-NMR was measured. Peaks observed around 0–10 ppm were identified as peaks originating from 6-coordinate aluminum atoms, and the presence or absence of these peaks was determined. Furthermore, a methanol solution of aluminum nitrate (Al concentration 5 ppm: by mass) with 1000 ppm of acetylacetone added was similarly measured as a standard solution, confirming that it was the peak position for 6-coordinate Al. As will be described later, the above ２７ Using a procedure similar to that used for Al-NMR measurements, a peak originating from four-coordinate aluminum atoms was observed around 54 ppm (50-65 ppm) in the aqueous dispersion silica sol of aluminum atom-containing silica particles (without the addition of acetylacetone to the aqueous dispersion silica sol) and the organosol after substitution with an organic solvent (the peak position of four-coordinate Al was also confirmed using the above standard solution).

[0112] (Measurement of acidity of particles in organosol) 35 g of the target organosol was mixed with the same mass of methanol, and 7 g of mixed bed ion exchange resin (a mixture of H-type strongly acidic cation exchange resin and OH-type strongly basic anion exchange resin type I) (product name) Muromac XSM-N411 HG (manufactured by Muromachi Chemical Co., Ltd.) was added and stirred for 1 hour. After removing the resin by mesh filtration, 60 g of the resulting sol was taken out, 30 g of ion-exchanged water was added and stirred, and while measuring the pH, a 0.05 N tetrabutylammonium aqueous solution (an aqueous solution obtained by diluting 0.5 N tetrabutylammonium aqueous solution manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. 10 times with pure water) was added. From the titration volume until the pH reached 7, the amount of base required to neutralize the silica particles per unit surface area (mol / m²) was determined. ２ The specific surface area (S) was calculated and used as the value for the acidity of the particles. Ｎ２ The formula used in the calculation was ).

[0113] (Thermal Stability Evaluation) 50 g of the inorganic particle-dispersed organosols of the examples and comparative examples described later were sealed in 100 ml glass bottles and stored at 50°C for 4 weeks. (Evaluation (1): Change in pH value before and after the test) The thermal stability of the silica sol was also evaluated by calculating the change in pH from the pH of the inorganic particle-dispersed organosol to be evaluated before and after storage at 50°C using the following formula (O) as an indicator of the change over time at 50°C for 4 weeks. However, (Y) in the following formula (O) ０ ) indicates the pH before the thermal stability test (immediately after sol preparation), (Y ４ｗ ) indicates the pH after the thermal stability test (after being held at 50°C for 4 weeks). pH change: (Y ４ｗ ) - (Y ０ ) ... (Formula (O)) Thermal stability was evaluated in four stages, A to D, as follows: <Thermal Stability Test (Change in pH Value) Evaluation Criteria> A: pH change less than 1.0 B: pH change of 1.0 or more and less than 2.0 C: pH change of 2.0 or more and less than 4.0 D: pH change of 4.0 or more

[0114] (Evaluation (2): Percentage change in particle size before and after testing) The DLS ratio was calculated from the average DLS particle size of the inorganic particle dispersion organosol to be evaluated before and after storage at 50°C using the following formula (N) as an indicator of the change over time at 50°C for 4 weeks, and the thermal stability of the silica sol was evaluated. In addition, if the DLS ratio value was between -10% and 0%, it was evaluated as a DLS ratio of 0%. However, (X) in the following formula (N) was omitted. ０ ) indicates the DLS average particle size before the thermal stability test (immediately after sol preparation), (X ４ｗ ) indicates the average DLS particle size after the thermal stability test (after being held at 50°C for 4 weeks). DLS ratio: [(X ４ｗ ) - (X ０ ) / (X ０ ) ] × 100 (%) ... (Formula (N)) Thermal stability was evaluated in the following four stages A to D. <Thermal stability test (rate of change in particle size) evaluation criteria> A: DLS ratio is less than 10% B: DLS ratio is 10% or more and less than 15% C: DLS ratio is 15% or more and less than 20% D: DLS ratio is 20% or more, or silica sol becomes cloudy, phase separation occurs, or precipitates form

[0115] [Example 1] 2000 g of aqueous-dispersed silica sol A was placed in a 3 L plastic container and stirred at a rotation speed of 650 rpm using a mechanical stirrer equipped with a glass stirring blade. Under this stirring, Al ２ O ３ 35.0 g of an aqueous sodium aluminate solution diluted to a concentration of 1.0% by mass was added dropwise over 1 minute, and the mixture was stirred at the same rotational speed for 30 minutes. 716 g of pure water was then added, and the mixture was stirred for an additional 10 minutes to obtain the mixture. Next, 2443 g of this mixture was placed in a 3 L stainless steel autoclave container and heated at 150°C for 5 hours under stirring at 80 rpm, and then cooled to below 50°C. 1000 g of the resulting aqueous dispersion silica sol of aluminum atom-containing hollow silica particles was placed in a 2 L round-bottom flask. Using a rotary evaporator, the pressure was reduced to 580 Torr, and the solvent (dispersion medium), water, was replaced with methanol (MeOH) while heated to 120°C. Methanol was then added to adjust the concentration, and a 20% by mass MeOH-dispersed silica sol (pH 6.1) of aluminum atom-containing hollow silica particles was obtained. 1000 g of the obtained MeOH-dispersed silica sol was passed through a 100 cc glass column packed with 100 ml of cation exchange resin at a space velocity (sv) of 7 / hour to obtain cation exchange-treated MeOH-dispersed silica sol 1. Including the subsequent examples, the state of aluminum atoms on the surface of hollow silica particles was examined for the aqueous dispersion silica sol of aluminum atom-containing silica particles and the organosol after organic solvent substitution. ２７ Al-NMR measurements confirmed the presence of four-coordinate aluminum atoms.

[0116] [Example 2] 200 g of cation exchange treated MeOH-dispersed silica sol 1 was placed in a 500 mL round-bottom flask, and MeOH was removed by distillation while adding PGME in a rotary evaporator under a pressure of 450 to 100 Torr and a bath temperature of 80 to 90°C to obtain PGME-dispersed silica sol 1 with a silica particle concentration of 20% by mass.

[0117] [Example 3] 200 g of cation exchange treated MeOH-dispersed silica sol 1 was placed in a 500 mL round-bottom flask, 0.04 g of MEHQ and 2.0 g of MPS were added, and after stirring, the mixture was heated at 60°C for 3 hours. The resulting sol was heated in a rotary evaporator at a pressure of 500-450 Torr and a bath temperature of 80°C, and MeOH was removed by distillation while adding MEK to obtain MEK-dispersed silica sol 1 with a silica particle concentration of 20% by mass.

[0118] [Example 4] 200 g of cation exchange treated MeOH-dispersed silica sol 1 was placed in a 500 mL round-bottom flask, and 20.0 g of n-butanol (n-BtOH) and 88 g of MIBK were added. Then, the methanol (MeOH) solvent was removed by distillation in a rotary evaporator under reduced pressure of 450 Torr and heated at a bath temperature of 80°C to obtain 200 g of sol with a silica particle concentration of 20.0 mass%. 0.04 g of MEHQ and 2.0 g of MPS were added to the obtained sol, and then a reflux condenser was attached to the 500 mL round-bottom flask, and heating and aging was carried out at a liquid temperature of 60°C for 3 hours. After that, the solvent of the sol was replaced using a rotary evaporator at a pressure of 450 to 115 Torr and a bath temperature of 80°C while supplying MIBK, to obtain 20 mass% silica particle concentration MIBK-dispersed silica sol 1.

[0119] [Example 5] 200 g of cation exchange treated MeOH-dispersed silica sol 1 was placed in a 500 mL round-bottom flask, and 0.04 g of MEHQ and 2.0 g of MPS were added. A reflux condenser was then attached to the 500 mL round-bottom flask, and the mixture was heated and matured at a liquid temperature of 60°C for 3 hours. Subsequently, the methanol (MeOH) solvent was removed by distillation using a rotary evaporator under reduced pressure of 450-70 Torr while adding PGMEA, and the mixture was heated at a bath temperature of 80°C to obtain 200 g of PGMEA-dispersed silica sol 1 with a silica particle concentration of 20% by mass.

[0120] [Example 6] 200 g of cation exchange treated MeOH-dispersed silica sol 1 was placed in a 1000 mL round-bottom flask, and 20 g of n-butanol (n-BtOH) and 88 g of MIBK were added. Then, using a rotary evaporator, the pressure was reduced to 450 Torr, and the solvent methanol (MeOH) was removed by distillation while the bath was heated at 80°C, yielding 200 g of sol with a silica particle concentration of 20.0 mass%. 0.04 g of MEHQ and 3.2 g of PTMS were added to the obtained sol, and then a reflux condenser was attached to the 1000 mL round-bottom flask, and heating and aging was carried out at a liquid temperature of 60°C for 3 hours. Then, using a rotary evaporator, the solvent methanol (MeOH) was removed by distillation while adding PGMEA under reduced pressure of 450-70 Torr, while the bath was heated at 80°C, yielding silica sol 2 with a silica particle concentration of 20 mass% PGMEA-dispersed silica sol.

[0121] [Example 7] 500 g of aqueous dispersion silica sol of aluminum atom-containing hollow silica particles obtained by the same method as in Example 1 was placed in a 2 L round-bottom flask and set in a rotary evaporator. Distillation was carried out under a bath temperature of 85-90°C and a reduced pressure of 350-100 Torr while supplying PGME, and the dispersion medium was replaced with PGME to obtain a PGME dispersion sol of aluminum atom-containing hollow silica particles. Next, 450 g of the obtained PGME dispersion silica sol of hollow silica particles was placed in a 1000 mL plastic container, 150 ml of cation exchange resin was added, and the mixture was held for 60 minutes while stirring at 100 times per minute with a mix rotor to obtain a PGME dispersion silica sol of hollow silica particles. Next, 400 g of the obtained PGME-dispersed silica sol of hollow silica particles was placed in a 1 L round-bottom flask, and while stirring with a magnetic turret, 0.06 g of MEHQ and 2.76 g of AcPS were added, and the mixture was heated to 60°C and held for 5 hours. The round-bottom flask containing the obtained silica sol was placed in a rotary evaporator, and the silica particle concentration was concentrated to 30% by mass or more under reduced pressure of 300-50 Torr at a bath temperature of 60°C to obtain PGME-dispersed silica sol 2 of hollow silica particles.

[0122] [Example 8] The procedure was carried out in the same manner as in Example 1, except that water-dispersible silica sol B was used instead of water-dispersible silica sol A, to obtain cation exchange treated MeOH-dispersed silica sol 2.

[0123] [Example 9] The procedure was carried out in the same manner as in Example 2, except that cation exchange treated MeOH-dispersed silica sol 2 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain PGME-dispersed silica sol 3.

[0124] [Example 10] The procedure was carried out in the same manner as in Example 3, except that cation exchange treated MeOH-dispersed silica sol 2 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain MEK-dispersed silica sol 2.

[0125] [Example 11] MIBK-dispersed silica sol 2 was obtained by following the same procedure as in Example 4, except that cation exchange-treated MeOH-dispersed silica sol 2 was used instead of cation exchange-treated MeOH-dispersed silica sol 1.

[0126] [Example 12] In Example 1, Al ２ O ３ The procedure was carried out in the same manner as in Example 1, except that the amount of sodium aluminate aqueous solution diluted to a concentration of 1.0% by mass was 17.5 g, to obtain cation exchange treated MeOH-dispersed silica sol 3.

[0127] [Example 13] The procedure was carried out in the same manner as in Example 3, except that cation exchange treated MeOH-dispersed silica sol 3 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain MEK-dispersed silica sol 3.

[0128] [Example 14] The procedure was carried out in the same manner as in Example 5, except that cation exchange treated MeOH-dispersed silica sol 3 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain PGMEA-dispersed silica sol 3.

[0129] [Example 15] In Example 1, Al ２ O ３The procedure was carried out in the same manner as in Example 1, except that the amount of sodium aluminate aqueous solution diluted to a concentration of 1.0% by mass was 70.0 g, to obtain cation exchange treated MeOH-dispersed silica sol 4.

[0130] [Example 16] The procedure was carried out in the same manner as in Example 3, except that cation exchange treated MeOH-dispersed silica sol 4 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain MEK-dispersed silica sol 4.

[0131] [Example 17] The procedure was carried out in the same manner as in Example 5, except that cation exchange treated MeOH-dispersed silica sol 4 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain PGMEA-dispersed silica sol 4.

[0132] [Example 18] The procedure was carried out in the same manner as in Example 1, except that 0.175 g of 8% sulfuric acid was added to 1000 g of aqueous dispersion silica sol of aluminum atom-containing hollow silica particles before methanol substitution, to obtain cation exchange treated MeOH-dispersed silica sol 5.

[0133] [Example 19] The procedure was carried out in the same manner as in Example 3, except that cation exchange treated MeOH-dispersed silica sol 5 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain MEK-dispersed silica sol 5.

[0134] [Example 20] The procedure was carried out in the same manner as in Example 5, except that cation exchange treated MeOH-dispersed silica sol 5 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain PGMEA-dispersed silica sol 5.

[0135] [Example 21] In Example 1, Al ２ O ３ The procedure was carried out in the same manner as in Example 1, except that the amount of sodium aluminate aqueous solution diluted to a 1.0% by mass concentration was 4.1 g, to obtain cation exchange treated MeOH-dispersed silica sol 6.

[0136] [Example 22] The procedure was carried out in the same manner as in Example 3, except that cation exchange treated MeOH-dispersed silica sol 6 was used instead of cation exchange treated MeOH-dispersed silica sol 1, to obtain MEK-dispersed silica sol 6.

[0137] [Example 23] 1841 g of aqueous-dispersible silica sol D was placed in a 3 L poly container and stirred at a rotational speed of 650 rpm using a mechanical stirrer equipped with a glass stirring blade. Under this stirring, Al ２ O ３ 62.3 g of an aqueous sodium aluminate solution diluted to a concentration of 1.0% by mass was added dropwise over 1 minute, and the mixture was stirred at the same rotational speed for 30 minutes. 596.4 g of pure water was then added, and the mixture was stirred for an additional 10 minutes to obtain the mixture. Next, 2499 g of this mixture was placed in a 3 L stainless steel autoclave container and heat-treated at 150°C for 5 hours under stirring at 80 rpm, and then cooled to below 50°C. 1000 g of the resulting heat-treated aqueous dispersion sol of aluminum atom-containing hollow silica particles was placed in a 2 L round-bottom flask. Using a rotary evaporator, distillation was performed while supplying MeOH at a bath temperature of 100-120°C and under reduced pressure of 600-500 Torr, replacing the water solvent (dispersion medium) with MeOH to obtain an MeOH dispersion sol of aluminum atom-containing hollow silica particles. The physical properties of the obtained MeOH-dispersed sol were as follows, determined by DLS method: average particle size 96 nm, pH 6.3, silica particle concentration 20.7% by mass, and water content 1.0% by mass. The obtained sol showed good dispersibility, with no precipitates. Subsequently, 1000 g of the obtained MeOH-dispersed silica sol was passed through a 100 cc glass column packed with 100 ml of cation exchange resin at a space velocity (sv) of 7 / hour to obtain cation exchange-treated MeOH-dispersed silica sol 7.

[0138] [Example 24] 203 g of cation exchange treated MeOH-dispersed silica sol 7 was placed in a 500 mL round-bottom flask, 0.04 g of MEHQ and 1.4 g of MPS were added, and after stirring, the mixture was heated at 60°C for 3 hours. The resulting sol was heated in a rotary evaporator at a pressure of 500-150 Torr and a bath temperature of 85°C, and MeOH was removed by distillation while adding PGME to obtain PGME-dispersed silica sol 4 with a silica particle concentration of 15% by mass.

[0139] [Example 25] The same procedure as in Example 24 was followed, except that 1.3 g of AcPS was added instead of 1.4 g of MPS, to obtain PGME-dispersed silica sol 5 with a silica particle concentration of 15% by mass.

[0140] [Example 26] 150 g of cation exchange treated MeOH-dispersed silica sol 7 was placed in a 500 mL round-bottom flask, and 15.0 g of n-butanol (n-BtOH) and 33.0 g of MMB (manufactured by Junsei Chemical Co., Ltd., special grade) were added. Then, the solvent methanol (MeOH) was removed by distillation under reduced pressure of 450 Torr using a rotary evaporator and heated at a bath temperature of 80°C, obtaining 146.9 g of sol concentrated to a silica particle concentration of 19.2% by mass. 0.03 g of MEHQ and 1.0 g of MPS were added to the obtained sol, and then a reflux condenser was attached to the 500 mL round-bottom flask, and heating and aging was carried out at a liquid temperature of 60°C for 3 hours. Subsequently, using a rotary evaporator, the sol was replaced with MMB while supplying it at a pressure of 450-115 Torr and a bath temperature of 80°C to obtain silica sol 1 dispersed in MMB with a silica particle concentration of 17.0 mass%.

[0141] [Example 27] The same procedure as in Example 26 was followed, except that PGMEA was used instead of MMB, to obtain a silica sol 6 dispersed with 18.0% by mass of PGMEA silica particles.

[0142] [Example 28] 120 g of cation exchange treated MeOH-dispersed silica sol 2 was placed in a 500 mL round-bottom flask, 0.02 g of MEHQ and 1.2 g of MPS were added, and after stirring, the mixture was heated at 60°C for 3 hours. The resulting sol was heated in a rotary evaporator at a pressure of 500-150 Torr and a bath temperature of 85°C, and MeOH was removed by distillation while adding PGME to obtain PGME-dispersed silica sol 6 with a silica particle concentration of 20% by mass.

[0143] [Example 29] 200 g of cation exchange treated MeOH-dispersed silica sol 7 was placed in a 1000 mL round-bottom flask, and 20.0 g of n-butanol (n-BtOH) and 88 g of MIBK were added. Then, using a rotary evaporator, the pressure was reduced to 450 Torr and the mixture was heated at a bath temperature of 80°C until the methanol (MeOH) in the solvent was reduced to 1% by mass or less. 0.04 g of MEHQ and 1.5 g of MPS were added, and a reflux condenser was attached to a 500 mL round-bottom flask. The mixture was heated and aged at a liquid temperature of 60°C for 3 hours. After that, the silica particle concentration was diluted to 15% by mass with MIBK, and the sol was replaced with MIBK while supplying it using a rotary evaporator at a pressure of 450-115 Torr and a bath temperature of 80°C to obtain 15% by mass MIBK-dispersed silica sol 3.

[0144] [Example 30] The procedure was carried out in the same manner as in Example 1, except that water-dispersible silica sol E was used instead of water-dispersible silica sol A, to obtain cation exchange treated MeOH-dispersed silica sol 8.

[0145] [Example 31] 200 g of cation exchange treated MeOH-dispersed silica sol 8 was placed in a 1000 mL round-bottom flask, 0.04 g of MEHQ and 1.7 g of MPS were added, and after stirring, the mixture was heated at 60°C for 3 hours. The resulting sol was diluted with PGME to a silica particle concentration of 15% by mass, and the MeOH was removed by distillation while adding PGME in a rotary evaporator under a pressure of 500-150 Torr and a bath temperature of 85°C, thereby concentrating the mixture to a silica particle concentration of 20% by mass to obtain PGME-dispersed silica sol 7.

[0146] [Example 32] 200 g of cation exchange treated MeOH-dispersed silica sol 8 was placed in a 1000 mL round-bottom flask, 0.04 g of MEHQ and 1.7 g of MPS were added, and after stirring, the mixture was heated at 60°C for 3 hours. The resulting sol was diluted with MEK to a silica particle concentration of 15% by mass, and the MeOH was removed by distillation while adding MEK in a rotary evaporator under a pressure of 500-450 Torr and a bath temperature of 80°C, thereby concentrating the mixture to a silica particle concentration of 20% by mass to obtain MEK-dispersed silica sol 7.

[0147] [Example 33] 200 g of cation exchange treated MeOH-dispersed silica sol 8 was placed in a 1000 mL round-bottom flask, and 20.0 g of n-butanol (n-BtOH) and 88 g of MIBK were added. Then, using a rotary evaporator, the pressure was reduced to 450 Torr and the mixture was heated at a bath temperature of 80°C until the methanol (MeOH) in the solvent was reduced to 1% by mass or less. 0.04 g of MEHQ and 1.7 g of MPS were added, and a reflux condenser was attached to the 1000 mL round-bottom flask. The mixture was heated and aged at a liquid temperature of 60°C for 3 hours. After that, the silica particle concentration was diluted to 15% by mass with MIBK, and the sol was replaced with MIBK while supplying it using a rotary evaporator at a pressure of 450-115 Torr and a bath temperature of 80°C, and concentrated to a silica particle concentration of 20% by mass to obtain MIBK-dispersed silica sol 4.

[0148] [Example 34] The procedure was carried out in the same manner as in Example 33, except that 1.65 g of AcPS was used instead of 1.7 g of MPS, to obtain MIBK-dispersed silica sol 5.

[0149] [Example 35] The procedure was carried out in the same manner as in Example 33, except that 3.30 g of AcPS was used instead of 1.7 g of MPS, to obtain MIBK-dispersed silica sol 6.

[0150] [Example 36] The procedure was carried out in the same manner as in Example 11, except that 1.79 g of AcPS was used instead of 1.7 g of MPS, to obtain MIBK-dispersed silica sol 7.

[0151] [Example 37] 200 g of cation exchange treated MeOH-dispersed silica sol 8 was placed in a 1000 mL round-bottom flask, 0.04 g of MEHQ and 1.7 g of MPS were added, and a reflux condenser was attached to the 1000 mL round-bottom flask. The mixture was then heated and matured at a liquid temperature of 60°C for 3 hours. After that, the silica particle concentration was diluted to 15% by mass with PGMEA, and the solvent methanol (MeOH) was removed by distillation in a rotary evaporator under reduced pressure of 450-70 Torr while adding PGMEA, while the bath temperature was heated to 80°C. The mixture was concentrated to a silica particle concentration of 20% by mass to obtain 200 g of PGMEA-dispersed silica sol 7.

[0152] [Example 38] In Example 1, water-dispersible silica sol F was used instead of water-dispersible silica sol A, and Al ２ O ３ The procedure was carried out in the same manner as in Example 1, except that the amount of sodium aluminate aqueous solution diluted to a concentration of 1.0% by mass was 70.0 g, to obtain a cation exchange treated MeOH-dispersed silica sol 9.

[0153] [Example 39] 200 g of cation exchange treated MeOH-dispersed silica sol 9 was placed in a 1000 mL round-bottom flask, and 20.0 g of n-butanol (n-BtOH) and 88 g of MIBK were added. Then, using a rotary evaporator, the pressure was reduced to 450 Torr and the mixture was heated at a bath temperature of 80°C until the methanol (MeOH) in the solvent was reduced to 1% by mass or less. 0.04 g of MEHQ and 1.7 g of MPS were added, and a reflux condenser was attached to the 1000 mL round-bottom flask. The mixture was heated and aged at a liquid temperature of 60°C for 3 hours. After that, the silica particle concentration was diluted to 15% by mass with MIBK, and the sol was replaced with MIBK while supplying it using a rotary evaporator at a pressure of 450-115 Torr and a bath temperature of 80°C, and the mixture was concentrated to a silica particle concentration of 20% by mass to obtain MIBK-dispersed silica sol 8.

[0154] [Example 40] The procedure was carried out in the same manner as in Example 39, except that the amount of MPS used was 3.4 g, to obtain MIBK-dispersed silica sol 9.

[0155] [Example 41] The procedure was carried out in the same manner as in Example 40, except that the amount of MEHQ used was 0.02 g, to obtain MIBK-dispersed silica sol 10.

[0156] [Example 42] The procedure was carried out in the same manner as in Example 40, except that the amount of MEHQ used was 0.01 g, to obtain MIBK-dispersed silica sol 11.

[0157] [Example 43] The procedure was carried out in the same manner as in Example 40, except that the amount of MEHQ used was 0.004 g, to obtain MIBK-dispersed silica sol 12.

[0158] [Example 44] The procedure was carried out in the same manner as in Example 39, except that the amount of MPS used was 5.1 g, to obtain MIBK-dispersed silica sol 13.

[0159] [Example 45] The procedure was carried out in the same manner as in Example 29, except that the amount of MPS used was 2.96 g, to obtain MIBK-dispersed silica sol 14.

[0160] [Example 46] The procedure was carried out in the same manner as in Example 29, except that the amount of MPS used was 4.44 g, to obtain MIBK-dispersed silica sol 15.

[0161] [Example 47] The procedure was carried out in the same manner as in Example 29, except that 1.40 g of AcPS was used instead of 1.5 g of MPS, to obtain MIBK-dispersed silica sol 16.

[0162] [Example 48] 200 g of cation exchange treated MeOH-dispersed silica sol 9 was placed in a 1000 mL round-bottom flask, 0.04 g of MEHQ and 3.4 g of MPS were added, and a reflux condenser was attached to the 1000 mL round-bottom flask. The mixture was then heated and aged at a liquid temperature of 60°C for 3 hours. After that, 32.2 g of water-dispersed silica sol G was added, and the mixture was heated and aged again at a liquid temperature of 60°C for 3 hours. Next, distillation was carried out while supplying MeOH until the water content in the sol was 1.5% by mass or less. Here, the silica particle concentration was diluted to 15% by mass with 20 g of n-butanol (n-BtOH) and MIBK. Using a rotary evaporator, the solvent of the sol was replaced while supplying MIBK at a pressure of 450 to 115 Torr and a bath temperature of 80°C, and the mixture was concentrated to a silica particle concentration of 20% by mass to obtain MIBK-dispersed silica sol 17.

[0163] [Example 49] The procedure was carried out in the same manner as in Example 48, except that the amount of water-dispersed silica sol G added was 62.3 g, to obtain MIBK-dispersed silica sol 18.

[0164] [Example 50] The procedure was carried out in the same manner as in Example 48, except that 28 g of pure water was added instead of water-dispersed silica sol G, to obtain MIBK-dispersed silica sol 19.

[0165] [Example 51] 200 g of cation exchange treated MeOH-dispersed silica sol 9 was placed in a 1000 mL round-bottom flask, and 20.0 g of n-butanol (n-BtOH) and 88 g of MIBK were added. Then, the mixture was reduced to 450 Torr using a rotary evaporator and heated at a bath temperature of 80°C until the methanol (MeOH) in the solvent was reduced to 1% by mass or less. 0.04 g of MEHQ and 3.4 g of MPS were added, and then a reflux condenser was attached to the 1000 mL round-bottom flask, and the mixture was heated and aged at a liquid temperature of 60°C for 3 hours. Subsequently, the silica particle concentration was diluted to 15% by mass with MIBK, and the sol was solvent-replaced using a rotary evaporator at a pressure of 450-115 Torr and a bath temperature of 80°C while supplying MIBK, thereby concentrating the silica particle concentration to 20% by mass. A reflux condenser was then attached again, and the sol was heated and aged at a liquid temperature of 60°C for 3 hours to obtain MIBK-dispersed silica sol 20.

[0166] [Example 52] MIBK-dispersed silica sol 21 was obtained in the same manner as in Example 48, except that 1.63 g of AcPS was added instead of 3.4 g of MPS.

[0167] [Example 53] MIBK-dispersed silica sol 22 was obtained in the same manner as in Example 48, except that 3.27 g of AcPS was added instead of 3.4 g of MPS.

[0168] [Example 54] MIBK-dispersed silica sol 23 was obtained in the same manner as in Example 48, except that 4.90 g of AcPS was added instead of 3.4 g of MPS.

[0169] [Example 55] The procedure was carried out in the same manner as in Example 11, except that 3.58 g of AcPS was used instead of MPS, to obtain MIBK-dispersed silica sol 24.

[0170] [Example 56] The procedure was carried out in the same manner as in Example 11, except that 5.37 g of AcPS was used instead of MPS, to obtain MIBK-dispersed silica sol 25.

[0171] [Example 57] 200 g of cation exchange treated MeOH-dispersed silica sol 7 was placed in a 1000 mL round-bottom flask, 0.04 g of MEHQ and 0.74 g of MPS were added, and the mixture was stirred. The mixture was then heated at 60°C for 3 hours. 0.70 g of AcPS was then added, the mixture was stirred, and the mixture was heated again at 60°C for 3 hours to obtain MeOH-dispersed silica sol 10.

[0172] [Example 58] 1200 g of cation exchange treated MeOH-dispersed silica sol 2 was mixed with 180 g of MEK and 12.5 g of MPDMS and heated at 60°C for 3 hours. 14.9 g of HMDS was added and stirred, then heated again at 60°C for 3 hours. 0.5 g of DiPEA was added and stirred, then heated again at 60°C for 1 hour. The resulting sol was heated in a rotary evaporator at a pressure of 500-450 Torr and a bath temperature of 80°C, and MeOH was removed while adding MEK to obtain MEK-dispersed silica sol 8 with a silica particle concentration of 20% by mass.

[0173] [Comparative Example 1] An aqueous silica sol of aluminum atom-containing hollow silica particles obtained by the same method as in Example 1 was attempted to be passed through 200 mL of cation exchange resin packed into a column at a space velocity (SV) of 5 / hour, but the column became blocked midway, and no aqueous sol was obtained.

[0174] [Comparative Example 2] 1000 g of aqueous silica sol of aluminum atom-containing hollow silica particles obtained by the same method as in Example 14 was mixed with 0.175 g of 8% sulfuric acid and stirred. Attempts were made to pass the mixture through 200 mL of cation exchange resin packed into a column at a space velocity (SV) of 5 / hour, but the column became blocked midway, and no aqueous sol was obtained.

[0175] [Comparative Example 3] 2000 g of aqueous-dispersed silica sol C was placed in a 3 L plastic container and stirred at a rotational speed of 650 rpm with a mechanical stirrer equipped with a glass stirring blade. Under this stirring, Al ２ O ３35.0 g of an aqueous sodium aluminate solution diluted to a concentration of 1.0% by mass was added dropwise over 1 minute, and the mixture was stirred at the same rotational speed for 30 minutes. 716 g of pure water was then added, and the mixture was stirred for an additional 10 minutes to obtain the mixture. Next, 2443 g of this mixture was placed in a 3 L stainless steel autoclave container and heat-treated at 150°C for 5 hours under stirring at 80 rpm, and then cooled to below 50°C. 1.51 g of an 8.2% aqueous sulfuric acid solution was added dropwise to 1700 g of the obtained heat-treated aqueous silica sol, and the mixture was stirred at a stirring speed of 800 rpm at room temperature for 1 hour to obtain a sulfuric acid-added heat-treated aqueous silica sol. Next, the obtained sulfuric acid-added heat-treated aqueous silica sol was passed through 200 mL of cation exchange resin packed into a column at a space velocity (SV) of 5 / hour to obtain an aqueous acidic silica sol of hollow silica particles containing aluminum atoms. The pH of the aqueous dispersion of aluminum atom-containing hollow silica particles obtained as an acidic silica sol was 2.8, and the silica particle concentration was 14.0% by mass. This sol was heat-treated at 80°C for 10 hours, cooled to room temperature, and then passed through 200 mL of cation exchange resin packed into a column at a space velocity (SV) of 5 / hour to obtain acidic silica sol 1. The pH of the acidic silica sol was 2.8, and the silica particle concentration was 13.8% by mass. The state of Al on the particle surface was also noted. ２７ Al-NMR measurement confirmed the presence of 4-coordinate Al. Subsequently, 1000 g of the obtained acidic silica sol 1 was placed in a 2 L round-bottom flask. Using a rotary evaporator, the pressure was reduced to 580 Torr and heated to 120°C, at which point the water, which was the solvent (dispersion medium), was replaced with methanol (MeOH). Further methanol was added to adjust the concentration, and a 20% by mass MeOH-dispersed silica sol (pH (1+1) 3.8) containing aluminum atom-containing hollow silica particles was obtained. 500 g of the obtained MeOH-dispersed silica sol was passed through a 100 cc glass column packed with 50 ml of cation exchange resin at a space velocity (sv) of 7 / hour to obtain cation exchange-treated MeOH-dispersed silica sol H1.

[0176] [Comparative Example 4] The procedure was carried out in the same manner as in Example 2, except that the cation exchange treated MeOH-dispersed silica sol H1 obtained in Comparative Example 3 was used instead of the cation exchange treated MeOH-dispersed silica sol 1 obtained in Example 2, to obtain PGME-dispersed silica sol H1.

[0177] [Comparative Example 5] The procedure was carried out in the same manner as in Example 5, except that the cation exchange treated MeOH-dispersed silica sol H1 obtained in Comparative Example 3 was used instead of the cation exchange treated MeOH-dispersed silica sol 1 obtained in Example 5, to obtain PGMEA-dispersed silica sol H1.

[0178] Tables 1 to 7 show the physical properties of the sols obtained in Examples 1 to 58 and Comparative Examples 1 to 5, as well as the results of the thermal stability evaluation performed using the above procedure. All silica sols obtained in the examples showed no precipitates, good dispersibility (dispersed in the dispersion medium without turbidity or aggregation), and good thermal stability with small changes in both pH and DLS. On the other hand, all silica sols obtained in the comparative examples either did not yield a sol at all (Comparative Examples 1 and 2) or had poor thermal stability (Comparative Example 3: significant increase in pH, Comparative Example 4: gelation, Comparative Example 5: significant increase in both pH and DLS).

[0179] In Tables 1-7, a "-" indicates that measurement data is unavailable for a component that was not added, or for reasons such as the dispersion not being obtained.

[0180]

[0181]

[0182]

[0183]

[0184]

[0185]

[0186]

[0187] As shown in Tables 1 to 6, the inorganic particle dispersion organosols of Examples 1 to 58 showed low fluctuations in pH value and DLS change rate even after thermal stability testing (held at 50°C for 4 weeks), confirming that they were highly stable organosols. On the other hand, the aqueous dispersion sol of aluminum atom-containing inorganic particles resulted in column blockage during the liquid passing process through the cation exchange resin, and an aqueous sol could not be obtained (Comparative Examples 1 and 2). Furthermore, the organosols of Comparative Examples 3 to 5, in which the acidic sol was replaced with an organic solvent, resulted in an anion content exceeding 100 ppm. Although these organosols showed good dispersibility with no precipitate immediately after production, they either gelled or, even if they did not gel, showed a large increase in pH value and a large change in the DLS average particle size during thermal stability testing (held at 50°C for 4 weeks), indicating poor thermal stability.

Claims

1. An inorganic particle dispersion organosol comprising four-coordinate aluminum atom-containing inorganic particles, anions, and an organic solvent, wherein the amount of aluminum atoms present in the entire inorganic particle is Al ２ O ３ An inorganic particle-dispersed organosol containing 100 to 50,000 ppm of the anion relative to the mass of the inorganic particles, and 0.1 to 50 ppm of the anion relative to the mass of the inorganic particle-dispersed organosol.

2. The inorganic particle-dispersed organosol according to claim 1, wherein the amount of TN (total nitrogen) contained in the inorganic particle-dispersed organosol is 0.01 to 0.20% by mass relative to the mass of the inorganic particles.

3. In a thermal stability test in which the inorganic particle-dispersed organosol is held at 50°C for 4 weeks, the (pH after thermal stability test) - (pH before thermal stability test) of the organosol is less than 4.0, and (average particle diameter by dynamic light scattering method after thermal stability test) / (average particle diameter by dynamic light scattering method before thermal stability test) × 100 (%) is less than 20%, the inorganic particle-dispersed organosol according to claim 1.

4. The inorganic particle-dispersed organosol according to claim 1, wherein the anion contains a sulfate ion, and the content of the sulfate ion is less than 30 ppm relative to the mass of the inorganic particle-dispersed organosol.

5. The inorganic particle dispersion organosol according to claim 1, wherein the inorganic particles are solid silica particles containing four-coordinate aluminum atoms or hollow silica particles containing four-coordinate aluminum atoms.

6. The inorganic particle-dispersed organosol according to claim 1, wherein the inorganic particles satisfy the following (i) to (iv): (i) the average primary particle diameter measured by transmission electron microscopy is 5 nm to 100 nm; (ii) the average particle diameter measured by dynamic light scattering is 5 nm to 150 nm; (iii) the inorganic particle content in the inorganic particle-dispersed organosol is 10% to 70% by mass; (iv) the acidity is 0.01 to 1.00 μmol / m³ ２ That is the case.

7. The inorganic particle dispersion organosol according to claim 5, wherein the hollow silica particles satisfy the following (V) to (Viii): (V) The outer shell thickness of the hollow silica particles is 2 to 15 nm; (Vi) The surface charge amount of the hollow silica particles, calculated per gram, is 10 μeq / g to 200 μeq / g; (Viii) The carbon content of the hollow silica particles, as determined by elemental analysis, is 0.1 mass% to 10.0 mass%.

8. ２７ The inorganic particle-dispersed organosol according to claim 1, wherein, in Al-NMR measurement, when acetylacetone is added to the inorganic particle-dispersed organosol at a concentration of 1000 ppm relative to the mass concentration of the inorganic particles and evaluated, it has one or more peaks indicating aluminum atoms other than four-coordinate atoms.

9. The inorganic particle dispersion organosol according to claim 1, wherein at least a portion of the inorganic particles are coated with a silane compound, and the silane compound is at least one silane compound selected from the group consisting of compounds represented by the following formulas (1) and (2): (In formula (1), R １ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ２ R is a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof, where a represents an integer from 1 to 3, and in formula (2), R ３ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ４ (where b represents a group or atom bonded to a silicon atom, independently representing an alkoxy group, acyloxy group, hydroxyl group, or halogen atom, or a combination thereof; Y represents a group or atom bonded to a silicon atom, representing an alkylene group, NH group, or oxygen atom; b represents an integer from 1 to 3; and c represents an integer of 0 or 1.) 10. The inorganic particles have a surface area of 1 nm ２ per particle and are particles whose surface is coated with the silane compound at a ratio of 0.1 to 10 per particle, or particles formed by bonding the silane compound to the surface. The inorganic particle-dispersed organosol according to claim 9.

11. The inorganic particle dispersion organosol according to claim 1, wherein the organic solvent comprises at least one selected from the group consisting of alcohols, ketones, ethers, esters, and amides.

12. The inorganic particle dispersion organosol according to claim 1, further comprising a reactive monomer, wherein the reactive monomer is at least one selected from the group consisting of (meth)acrylic compounds, polyfunctional (meth)acrylates, 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 anhydride, bismaleimide, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, propylene, or at least one silane compound selected from the group consisting of at least one compound represented by the following formulas (1) and (2). (In formula (1), R １ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ２ R is a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof, where a represents an integer from 1 to 3, and in formula (2), R ３ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ４ (where b represents a group or atom bonded to a silicon atom, independently representing an alkoxy group, acyloxy group, hydroxyl group, or halogen atom, or a combination thereof; Y represents a group or atom bonded to a silicon atom, representing an alkylene group, NH group, or oxygen atom; b represents an integer from 1 to 3; and c represents an integer of 0 or 1.) 13. A resin composition comprising four-coordinate aluminum atom-containing inorganic particles and a polymer, wherein the amount of aluminum atoms present in the entire inorganic particles is Al ２ O ３ A resin composition in which the amount of the polymer is 100 to 50,000 ppm relative to the mass of the inorganic particles, and the polymer is a polymer containing as a monomer component at least one monomer selected from the group consisting of (meth)acrylic compounds, polyfunctional (meth)acrylates, 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 anhydride, bismaleimide, vinyl-containing compounds, lactone ring-containing compounds, lactide-containing compounds, fluorine-containing compounds, cyclic olefin-containing compounds, ethylene, and propylene.

14. An inorganic particle-dispersed organosol according to claim 1 or a resin composition according to claim 13, which has an application as a material for anti-reflective coatings.

15. A method for producing an inorganic particle-dispersed organosol according to claim 1, comprising the step of replacing the dispersed water of an inorganic particle aqueous dispersion sol containing four-coordinate aluminum atom-containing inorganic particles and having a pH of 5 to 12 with an organic solvent by ultrafiltration, heating under reduced pressure, or heating under normal pressure.

16. A method for producing an inorganic particle dispersion organosol according to claim 15, further comprising the step of replacing the dispersed water in the aqueous dispersion sol with an organic solvent, followed by a step of cation exchange.

17. A method for producing an inorganic particle-dispersed organosol according to claim 16, further comprising the step of adding at least one silane compound selected from the group consisting of compounds represented by the following formulas (1) and (2) to an inorganic particle aqueous dispersion sol or inorganic particle-dispersed organosol containing four-coordinate aluminum atom-containing inorganic particles, before and / or after the step of substituting with the organic solvent, and heating and stirring at 10°C to 95°C for 0.1 hours to 20 hours. (In formula (1), R １ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ２ R is a group or atom bonded to a silicon atom, independently representing an alkoxy group, an acyloxy group, a hydroxyl group, or a halogen atom, or a combination thereof, where a represents an integer from 1 to 3, and in formula (2), R ３ R represents a group that is bonded to a silicon atom and independently represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, (meth)acryloyl group, mercapto group, amino group, ureido group, polyether group, carboxyl group, protected carboxyl group, carboxyl group generating group, imide group, or cyano group, and is bonded to a silicon atom by a Si-C bond, or represents a combination of these groups. ４ (where b represents a group or atom bonded to a silicon atom, independently representing an alkoxy group, acyloxy group, hydroxyl group, or halogen atom, or a combination thereof; Y represents a group or atom bonded to a silicon atom, representing an alkylene group, NH group, or oxygen atom; b represents an integer from 1 to 3; and c represents an integer of 0 or 1.) 18. A method for producing an inorganic particle dispersion organosol according to claim 15, comprising the step of replacing the dispersion medium with a reactive monomer, a polymer, or an organic solvent with a lower dielectric constant after the step of replacing with an organic solvent.

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