Hollow silica sol containing monovalent alkali metal ion and production method thereof

Abstract

To provide: hydrosol and organic solvent sol including a highly stable hollow silica particle; and a method for increasing stability of the sol having decreased storage stability and a production method thereof.SOLUTION: Hollow silica sol includes: a hollow silica particle having a space enclosed by a shell; and a monovalent alkali metal ion. The monovalent alkali metal ion is included in the sol at a ratio of a molar number thereof in terms of M2O (where M represents a monovalent alkali metal atom) to a molar number of SiO2 of the hollow silica particle of 7.12×10-6 to 285×10-6. In the sol, an average particle diameter determined by dynamic light scattering after storage at 50°C for 48 hours is in a range of at most 2.0 times the average particle diameter determined by the dynamic light scattering before the storage. The average particle diameter determined by the dynamic light scattering is 20 to 150 nm. In a stabilization method, the monovalent alkali metal ion is added to the hollow silica sol having a value of a particle diameter determined by the dynamic light scattering increased compared with that in production at the ratio described above relative to the SiO2 of the hollow silica particle in the hollow silica sol to decrease the increased value of the particle diameter determined by the dynamic light scattering.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a sol in which hollow silica particles containing monovalent alkali metal ions such as sodium ions are dispersed in water or an organic solvent, a method for producing the same, and a film-forming composition.

Background Art

[0002] Hollow silica particles having a silica outer shell and a space inside the outer shell have characteristics such as a low refractive index, low thermal conductivity (heat insulation property), and electrical insulation property due to their characteristics. Hollow silica particles are composed of a core corresponding to the hollow part 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 the core in an aqueous medium and then removing the core. The average particle diameter is in the range of 5 to 500 nm, the refractive index is in the range of 1.15 to 1.38, silica is represented by SiO2, and the inorganic oxide other than silica is MO X When represented by, the molar ratio MO X / SiO2 is in the range of 0.0001 to 0.2, and the content of alkali metal oxide is 5 ppm or less as A2O (A: alkali metal element). Silica-based fine particles having a cavity inside the outer shell are disclosed (see Patent Document 1).

[0003] Silica-based fine particles having a porous substance and / or a cavity inside the outer shell layer, wherein the ratio (SB / SC) of the specific surface area (SB) of the fine particles measured by the BET method to the specific surface area (SC) represented by the following formula is in the range of 1.1 to 5, the refractive index is in the range of 1.15 to 1.38, the content of alkali metal oxide is 5 ppm or less as M2O (M: alkali metal element) per silica-based fine particle, and the content of ammonia and / or ammonium ions per silica-based fine particle is 1500 ppm or less as NH3. Silica-based fine particles are disclosed (see Patent Document 2). SC (m 2 / g) = 6000 / Dp (nm)·ρ (However, Dp is the average particle diameter (nm) of the silica-based fine particles, and ρ is the density (g / ml).)

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention relates to an aqueous sol and an organic solvent sol containing highly stable hollow silica particles, and further relates to a method for improving the stability of the sol with reduced storage stability and a production method thereof.

Means for Solving the Problems

[0006] In a first aspect, the present invention includes hollow silica particles having a space inside the outer shell and monovalent alkali metal ions, and the number of moles of the monovalent alkali metal ions converted to M2O (where M represents a monovalent alkali metal atom) is 7.12×10 -6 ~285×10 -6 relative to the number of moles of SiO2 of the hollow silica particles. The sol has an average particle diameter by dynamic light scattering method after storing the sol at 50°C for 48 hours within a range of 2.0 times or less compared to the average particle diameter by dynamic light scattering method before storage, or a sol containing hollow silica particles having a space inside the outer shell and a molar ratio of monovalent alkali metal ions to SiO2 of the hollow silica particles converted to M2O (where M is a monovalent alkali metal) of 7.12×10 -6 ~285×10 -6 wherein the value of the particle diameter by dynamic light scattering method of the sol after storing the sol at 50°C for 48 hours is within a range of 2.0 times or less compared to before storage for the above-mentioned hollow silica sol, As a second aspect, the hollow silica sol according to the first aspect, wherein the monovalent alkali metal ion is a sodium ion, As a third aspect, the hollow silica sol according to the first or second aspect, wherein the average particle diameter by the dynamic light scattering method is 20 to 150 nm, As a fourth aspect, the hollow silica sol according to any one of the first to third aspects, further comprising an amine, wherein the amine is 0.001 to 10% by mass based on SiO2 of the hollow silica particles, As a fifth aspect, the hollow silica sol according to the fourth aspect, wherein the amine is at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines having 1 to 10 carbon atoms, As a sixth aspect, the hollow silica sol according to the fourth or fifth aspect, wherein the amine is a water-soluble amine having a water solubility of 80 g / L or more, As a seventh aspect, the hollow silica sol according to any one of the first to sixth aspects, further comprising an aluminum atom that forms an aluminosilicate site in the hollow silica particles, the aluminum atom being bonded to the surface of the hollow silica particles, and the mass of the aluminum atom being in the range of 100 to 20,000 ppm in terms of Al2O3 with respect to the mass of SiO2 of the hollow silica particles (ratio (A)), and the mass of the aluminum atom being a value measured by the leaching method, Or, the hollow silica sol according to any one of the first to sixth aspects, further comprising an aluminum atom that forms an aluminosilicate site in the hollow silica particles, the aluminum atom being a hollow silica particle in which the aluminum atom measured by the leaching method is bonded to the surface of the hollow silica particles at a ratio of 100 to 20,000 ppm / SiO2 in terms of Al2O3 per 1 g of SiO2 of the hollow silica particles, As an eighth aspect, the hollow silica sol according to the seventh aspect, wherein the leaching method measurement for leaching aluminum atoms from a compound containing aluminum atoms bonded to the surface of the hollow silica particles uses an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, Alternatively, the compound containing aluminum atoms bound to the surface of hollow silica particles obtained by leaching the hollow silica particles by the leaching method with an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, in terms of Al2O3, is the ratio (A) to 1 g of SiO2 of the hollow silica particles. The hollow silica sol according to the seventh aspect, As a ninth aspect, the mass of aluminum atoms present in the entire hollow silica particles is represented by a ratio (B) of 120 to 50,000 ppm with respect to the mass of SiO2 of the hollow silica particles in terms of Al2O3. The mass of the aluminum atoms is a value measured by a dissolution method using an aqueous hydrofluoric acid solution for the hollow silica particles. The hollow silica sol according to the seventh aspect or the eighth aspect, wherein the ratio (A) / the ratio (B) is 0.002 to 1.0, Alternatively, the aluminum atoms present in the entire hollow silica particles measured by the dissolution method using an aqueous hydrofluoric acid solution for the hollow silica particles are bonded at a ratio of 120 to 50,000 ppm / SiO2 in terms of Al2O3 to 1 g of SiO2 of the hollow silica particles, and the hollow silica sol according to the seventh aspect or the eighth aspect, wherein (A) / (B) is 0.001 to 1.0, As a tenth aspect, the ratio of [specific surface area (C) of silica particles by the BET method (nitrogen gas adsorption method)] / [specific surface area (D) of silica particles converted from a transmission electron microscope] is 1.40 to 5.00. The hollow silica sol according to any one of the first to ninth aspects, containing the hollow silica particles,

[0007] As an eleventh aspect, the hollow silica sol according to any one of the first to tenth aspects, containing hollow silica particles having a surface charge amount of 5 to 250 μeq / g per gram in terms of SiO2, Alternatively, the hollow silica sol according to any one of the first to tenth aspects, containing hollow silica particles having a surface charge amount of 5 to 250 μeq / g converted per gram of SiO2 of the hollow silica particles, silica sol, As a twelfth aspect, the above hollow silica particles further have the following formulas (1) and (2):

Chemical formula

Advantages of the Invention

[0008] A dispersion containing hollow silica particles (hollow silica sol) has stability, so that aggregation of the hollow silica particles does not occur, and a hollow silica sol with little change in the hollow silica particle diameter can be obtained. When a highly stable hollow silica sol is used as a coating film, since the change in particle diameter is small, reduction of unevenness on the coating film surface and improvement of transparency can be achieved. The alkali metal ions (e.g., sodium ions) in the hollow silica sol are preferably within a certain range. If there are too many, problems may occur in the elution of alkali metal ions from the coating film and the electrical insulation of the coating film. On the other hand, if there are too few, when the hollow silica particles have a cavity inside the outer shell and the specific gravity of the hollow silica particles themselves is lower than that of solid silica particles, so that the repulsive force of the particles is low, the particles tend to gather and aggregate easily. In that case, a certain amount of alkali metal ions (e.g., sodium ions) is required to increase the particle repulsive force.

[0009] In the present invention, as an alkali component, the combination of an amine molecule and sodium ions, etc. improves the stability. This is considered to be because the bulky amine molecules and sodium ions exist on the particle surface, and the repulsive force between silica particles is further improved. In addition, in the present invention, it is possible to form an aluminosilicate site by doping the silica particles with aluminum atoms on the particle surface, and the stability of the aluminosilicate site is improved by the presence of an alkali metal as a counter ion to the negatively charged aluminum atoms.

Embodiments for Carrying Out the Invention

[0010] The present invention includes hollow silica particles having a space inside the outer shell and monovalent alkali metal ions, and the molar ratio of the monovalent alkali metal ions to SiO2 of the hollow silica particles converted to M2O (where M represents a monovalent alkali metal atom) is 7.12×10 -6~285×10 -6 It is a hollow silica sol containing at a ratio of -6 , and the value of the particle diameter by the dynamic light scattering method (average particle diameter) after storing the sol at 50 °C for 48 hours is within a range of 2.0 times or less compared to the value of the particle diameter by the dynamic light scattering method before storage. Hollow silica particles have a silica outer shell and have a space inside the outer shell. Hollow silica is obtained by forming an outer shell mainly composed of silica on the surface of a portion corresponding to a core called a so-called template in a dispersion medium and removing the portion corresponding to the core.

[0011] Although it is required that hollow silica particles be stably dispersed in a dispersion medium, the presence of silanol groups on the surface of hollow silica particles, the presence of organic functional groups, the presence of aluminosilicate sites doped with aluminum atoms, etc. are stabilized by imparting monovalent alkali metal ions to the surface of the hollow silica particles. Silanol groups, organic functional groups, and aluminosilicate sites have polymerizable functional groups such as hydroxyl groups, and the interaction between these polymerizable functional groups leads to destabilization of the particles and an increase in particle diameter due to weak condensation (entanglement) between particles and interparticle crosslinking by hydrogen bonding. However, it is considered that when monovalent alkali metal ions are added to these polymerizable functional groups, the form of the hydroxyl groups changes and the factors causing destabilization are suppressed. These polymerizable functional groups may be promoted to be destabilized by heating, and the stability of the hollow silica sol can be evaluated by confirming its stability after 50 °C for 48 hours. Examples of the monovalent alkali metal ions include lithium ions, sodium ions, potassium ions, rubidium ions, and cesium ions. Preferably, lithium ions, sodium ions, and potassium ions are mentioned, and particularly preferably sodium ions are mentioned.

[0012] The content of the monovalent alkali metal ions is 7.12×10 in terms of the molar ratio of the monovalent alkali metal ions converted to M2O (where M represents a monovalent alkali metal atom) per mass of SiO2 of the hollow silica particles in the dispersion liquid (sol). -6 ~285×10 -6 or 7.12×10-6 ~237×10 -6 、 or 7.12×10 -6 ~190×10 -6 、 or 20×10 -6 ~285×10 -6 、 or 50×10 -6 ~285×10 -6 can be set as such. In addition, the content of the monovalent alkali metal ion can be set to an amount corresponding to a molar ratio of 15 ppm to 600 ppm, or 15 ppm to 500 ppm, or 15 ppm to 400 ppm, with respect to the mass of SiO2 of the hollow silica particles in the dispersion liquid (sol), where the monovalent alkali metal ion is converted to M2O (where M represents a monovalent alkali metal atom).

[0013] The average particle diameter of the hollow silica sol of the present invention can be set in the range of 20 to 150 nm by the dynamic light scattering method. And the value of the particle diameter by the dynamic light scattering method after storing the hollow silica sol at 50 °C for 48 hours is within 2.0 times, or 1.5 times, or 1.1 times compared to before storage. Also, it is included in the present invention that the particle diameter by the dynamic light scattering method after storing at 50 °C for 48 hours becomes smaller than before storage. Therefore, the lower limit value can be set to 0.8 times or more, or 0.9 times or more, or 1.0 times or more. In the present invention, by containing sodium ions in the above range, the stability of the hollow silica sol can be ensured, which means that sodium ions can be contained in the above range before the sol containing the hollow silica particles becomes unstable. Also, by adding the above sodium ions to the sol containing the destabilized hollow silica particles, the aggregated state of the hollow silica particles can be released and returned to the particle diameter range of the hollow silica particles in the state before aggregation.

[0014] In the present invention, aluminum atoms can be measured on the surface of silica particles by a leaching method using an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, and then expressed in terms of Al2O3. That is, the mass of aluminum atoms measured by the leaching method is such that the aluminum atoms are bonded to the silica particles at a ratio (A) of 100 to 20,000 ppm / SiO2, or 100 to 15,000 ppm / SiO2, 100 to 10,000 ppm / SiO2, or 200 to 5,000 ppm / SiO2, or 500 to 5,000 ppm / SiO2, or 800 to 3,000 ppm / SiO2 in terms of Al2O3 with respect to the mass of SiO2 of the hollow silica particles on the surface of the hollow silica particles. The presence of aluminum atoms on the surface of silica particles to form aluminosilicate sites is important for dispersion in solvents and resins. Aluminum atoms present as aluminosilicate on the surface of silica particles can be leached (eluted) in an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid, with the aluminum atoms having a structure close to that of an aluminum salt, aluminum oxide, or aluminum hydroxide. Then, the aluminum atoms can be measured from the solution using an ICP emission spectrometer and expressed in terms of Al2O3. In particular, a method of leaching (eluting) using a nitric acid aqueous solution is used. The nitric acid aqueous solution used for leaching can be used in the range where the pH of the aqueous solution is 0.5 to 4.0, 0.5 to 3.0, 0.5 to 2.0, or 1.0 to 1.5. Typically, a nitric acid aqueous solution with a pH of 1.0 can be used. For example, 100 mL of the above-mentioned nitric acid aqueous solution can be added to 1 g of silica, and the mixture can be held at a temperature of 20 to 70°C, or 40 to 60°C for 10 to 24 hours to elute the aluminum compound from the surface of the silica particles, which can be used as an analytical sample.

[0015] In the present invention, the surface of the silica particles can be defined as the region where the aluminum compound can be eluted by the above-mentioned leaching. That is, the silica gel obtained by evaporating the solvent from the silica sol and further drying at 250 °C is ground into silica powder. 20 mL of a nitric acid aqueous solution with a pH of 1.0 is added to 0.2 g of the silica powder, shaken well, held in a constant temperature bath at 50 °C for 17 hours, and then centrifuged and filtered. The aluminum content in the filtrate is measured with an ICP emission spectrometer, and the aluminum content converted to Al2O3 is divided by the mass of the silica powder to obtain the amount of aluminum (Al2O3 / SiO2) (ppm) bonded to the surface of the silica particles. Also, when forming an aluminosilicate on the surface of the silica particles, depending on the manufacturing method, aluminosilicate may be formed not only selectively on the surface but also inside the silica particles. The mass of aluminum atoms present in the entire hollow silica particles including the surface and the inside is in a ratio (B) of 120 to 50000 ppm / SiO2, or 500 to 20000 ppm / SiO2, or 500 to 10000 ppm / SiO2, or 1000 to 5000 ppm / SiO2, or 1000 to 4000 ppm / SiO2 in terms of Al2O3 conversion with respect to the mass of SiO2 of the hollow silica particles, and is bonded to the silica particles.

[0016] The ratio (A) / ratio (B), which is the ratio of aluminum present on the surface of the silica particles to that present in the entire silica particles, can be set in the range of 0.001 to 1.0, or 0.01 to 1.0, or 0.1 to 1.0, or 0.3 to 1.0, or 0.4 to 1.0. The aluminum atoms present in the entire silica particles can be measured by dissolving the silica particles with a hydrofluoric acid aqueous solution by a dissolution method and shown in terms of Al2O3 conversion. That is, the aluminum atoms present as aluminosilicate in the entire silica particles can be dissolved by a hydrofluoric acid aqueous solution. and can be measured from the solution using an ICP emission spectrometer, and can show the aluminum atoms present in the entire silica particles in terms of Al2O3. The hydrofluoric acid aqueous solution may have a concentration capable of dissolving the silica particles. For example, a 48% by mass hydrofluoric acid aqueous solution can be used. Further, to completely dissolve the silica particles, the amount of the hydrofluoric acid aqueous solution used needs to be equivalent or more to the silica particles, and preferably is 1.1 to 1000 equivalents in terms of molar ratio.

[0017] By forming aluminosilicate sites on the surface of the silica particles in this way, the amount of negative charge (surface charge amount) of the hollow silica particles present on the surface of the silica particles is measured in the range of 5 to 250 μeq / g, or 5 to 150 μeq / g, or 5 to 100 μeq / g, or 25 to 150 μeq / g, or 25 to 100 μeq / g per gram in terms of SiO2. The above hollow silica particles can be obtained as a hollow silica sol dispersed in a dispersion medium. A hollow silica sol in which the hollow silica particles are dispersed in a dispersion medium and the average particle diameter by the dynamic light scattering method is 20 to 150 nm can be obtained. Hollow silica is obtained by forming a silica-based outer shell on the surface of a part corresponding to a core called a so-called template in a dispersion medium and removing the part corresponding to the core. In this state, it is a hollow silica aqueous sol. The hollow silica aqueous sol thus obtained can be solvent-exchanged with an alcohol solvent as an organic solvent. The above alcohol solvent is preferably an alcohol having 1 to 5 carbon atoms which may have an ether bond, and examples include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like. Thereafter, if desired, after coating with a silane compound, it can be further solvent-exchanged with another organic solvent.

[0018] In the present invention, examples of the organic solvent include alcohols, ketones, ethers, amides, ureas, and esters having 1 to 10 carbon atoms. Alcohols having 1 to 10 carbon atoms are aliphatic alcohols, and include primary alcohols, secondary alcohols, and tertiary alcohols. And it is also possible to use polyhydric alcohols, for example, dihydric alcohols and trihydric alcohols.

[0019] Examples of monohydric primary alcohols include methanol, ethanol, 1-propanol, 1-butanol, 1-hexanol, etc. Examples of monohydric secondary alcohols include 2-propanol, 2-butanol, cyclohexanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. Examples of monohydric tertiary alcohols include Tert-butyl alcohol, etc. Examples of dihydric alcohols include methanediol, ethylene glycol, propylene glycol, etc. Examples of trihydric alcohols include glycerin, etc.

[0020] As the ketones having 1 to 10 carbon atoms, aliphatic ketones can be preferably used. For example, acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, methyl cyclopentanone, etc. As the ethers having 1 to 10 carbon atoms, aliphatic ethers can be preferably used. For example, dimethyl ether, ethyl methyl ether, diethyl ether, tetrahydrofuran, 1,4-dioxane, etc.

[0021] Examples of amides having 5 to 20 carbon atoms include N-methylpyrrolidone, dimethylacetamide, diethylacetamide, etc. Examples of ureas having 5 to 20 carbon atoms include tetramethylurea, 1,3-dimethyl-2-imi dazolidinone, etc. As the ester having 1 to 10 carbon atoms, an aliphatic ester can be preferably used. For example, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethyl acrylate, propyl acrylate, dimethyl maleate, diethyl maleate, dipropyl maleate, dimethyl adipate, diethyl adipate, dipropyl adipate, etc. can be mentioned.

[0022] In the above-mentioned raw materials, the hollow silica aqueous sol and the hollow silica organic solvent sol, the average particle diameter of the hollow silica particles by the dynamic light scattering method (DLS method) can be in the range of 20 to 150 nm, or 30 to 150 nm, or 40 to 150 nm, or 50 to 150 nm, or 50 to 120 nm, or 50 to 100 nm. Also, the average primary particle diameter by transmission electron microscope observation can be in the range of 20 to 150 nm, or 30 to 150 nm, or 40 to 150 nm, or 50 to 150 nm, or 50 to 120 nm, or 50 to 100 nm.

[0023] Also, the specific surface area (C) by the BET method (nitrogen gas adsorption method) can be set to 18 to 200 m 2 / g, or 50 to 160 m 2 / g, or 60 to 160 m 2 / g, or 70 to 160 m 2 / g, or 80 to 150 m 2 / g. Also, the specific surface area (D) converted from the transmission electron microscope can be set to 18 to 136 m 2 / g, or 18 to 90 m 2 / g, or 18 to 68 m 2 / g, or 18 to 54 m 2 / g, or 18 to 27 m 2 / g, or 18 to 23 m 2 / g.

[0024] And the ratio of [specific surface area (C) by BET method (nitrogen gas adsorption method)] / [specific surface area (D) converted from transmission electron microscope] can be set in the range of 1.40 to 5.00, or 1.40 to 3.50, or 1.50 to 3.00, or 1.50 to 2.80. When the value of (C) / (D) is close to 1.0, it is solid silica particles with no space inside the outer shell of the silica particles. When the value of (C) / (D) exceeds 1.0, it indicates that the silica particles are hollow silica particles with space inside the outer shell. Also, the thickness of the outer shell of the hollow silica particles by transmission electron microscope observation can be manufactured in the range of 3.0 to 15.0 nm, or 4.0 to 12.0 nm, or 5.0 to 10.0 nm. And the refractive index of the above hollow silica particles can be obtained in the range of 1.20 to 1.45, or 1.20 to 1.40, or 1.25 to 1.40.

[0025] Also, the concentration of SiO2 particles in the hollow silica sol is 1 to 50% by mass, or 5 to 40% by mass, and typically can be used at 10 to 30% by mass. The pH of the above sol can be adjusted from acidic to alkaline. Adjustment to acidic is carried out by adding an inorganic acid or an organic acid. Also, adjustment to alkaline is carried out by adding an inorganic base or an organic base, and as the organic base, an amine can be added for the purpose of adjusting the pH and the surface charge amount. The pH can be set to less than pH 1 to 7 on the acidic side and pH 7 or more and 13 or less on the alkaline side.

[0026] The aqueous sol of hollow silica can be set in the range of, for example, pH 2.0 to 6.0, or pH 2.0 to 4.5 before adding the amine, and by adding the amine, it can be adjusted to the range of, for example, pH 3.0 to 10.0, or 3.0 to 9.0. In the case of an organic solvent sol, the above pH is the pH when pure water of the same mass as the organic solvent sol is mixed at a ratio of 1:1, and the organic solvent can be measured when using an organic solvent that can be mixed with water. However, when later solvent substitution is carried out with a hydrophobic organic solvent, it is preferable to measure the pH at the stage of a methanol solvent sol in advance. For example, for a dispersion medium such as a methanol sol or a propylene glycol monomethyl ether sol which is a hydrophilic organic solvent, measurement is carried out using a solution obtained by mixing pure water and the sol at a mass ratio of 1:1. For a dispersion medium such as a methyl ethyl ketone sol which is a hydrophobic organic solvent, measurement can be carried out using a solution obtained by mixing pure water, methanol and the methyl ethyl ketone sol at a mass ratio of 1:1:1.

[0027] In the hollow silica organic solvent sol, solvent substitution of an aqueous medium into an alcohol solvent having 1 to 5 carbon atoms and further solvent substitution into an organic solvent are carried out, and moisture can remain in the process. At the stage of the alcohol sol of hollow silica, for example, the residual moisture can be contained in the sol in an amount of 0.1 to 3.0% by mass, or 0.1 to 1.0% by mass. And at the stage of the organic solvent sol of hollow silica (the dispersion medium is an organic solvent other than alcohol), it can be contained in an amount of 0.01 to 0.5% by mass. Also, in the hollow silica organic solvent sol, the viscosity can be set in the range of 1.0 to 10.0 mPa·s.

[0028] An amine can be added to the hollow silica sol of the present invention. As the amine used in the present invention, a water-soluble amine having a water solubility of 80 g / L or more, or 100 g / L or more can be used. In the hollow silica aqueous sol as a raw material and the hollow silica organic solvent sol obtained by solvent substitution, an amine, or an amine and ammonia can be contained. The amine can be added and contained in the range of 0.001 to 10% by mass, or 0.01 to 10% by mass, or 0.1 to 10% by mass with respect to SiO2 of the hollow silica particles. And the amine, or the amine and ammonia can be shown as the total nitrogen amount in the organic solvent sol of the hollow silica particles, and can be contained, for example, in the range of 10 to 100000 ppm, or 100 to 10000 ppm, or 100 to 3000 ppm, or 100 to 2000 ppm, typically 200 to 2000 ppm.

[0029] Examples of the above amines include aliphatic amines and aromatic amines, and aliphatic amines can be 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. For example, examples of the primary amine include monomethylamine, monoethylamine, monopropylamine, monoisopropylamine, monobutylamine, monoisobutylamine, monosec-butylamine, monotert-butylamine, monomethanolamine, monoethanolamine, monopropanolamine, monoisopropanolamine, monobutanolamine, monoisobutanolamine, monosec-butanolamine, monotert-butanolamine, etc.

[0030] Examples of the secondary amine include dimethylamine, diethylamine, dipropylamine, diisopropylamine, N-methylethylamine, N-ethylisobutylamine, dimethanolamine, diethanolamine, dipropanolamine, diisopropanolamine, N-methanolethylamine, N-methylethanolamine, N-ethanolisobutylamine, N-ethylisobutanolamine, etc. Examples of the tertiary amine include trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, triisobutylamine, trisec-butylamine, tritert-butylamine, trimethanolamine, triethanolamine, tripropanolamine, triisopropanolamine, tributanolamine, triisobutanolamine, trisec-butanolamine, tritert-butanolamine, tripentylamine, ethyl 3-(dimethylamino)acrylate, 2-(dimethylamino)ethyl acrylate, 2-(dimethylamino)ethyl methacrylate, 2-(diethylamino)ethyl acrylate, 2-(diethylamino)ethyl methacrylate, etc.

[0031] The water solubility of the above amine is preferably 80 g / L or more, or 100 g / L or more and can be preferably used. As these amines, primary amines and secondary amines are preferred, and secondary amines are preferably used because of their low volatility and high solubility. Examples thereof include diisopropylamine, diethanolamine, and the like. In the present invention, by containing the above amine, the surface charge amount of the hollow silica particles can be set to 5 μeq / g or more, or 25 μeq / g or more per gram in terms of SiO2. Typically, it can be set in the range of 5 to 250 μeq / g, or 25 to 250 μeq / g, or 25 to 100 μeq / g, or 25 to 80 μeq / g. In the present invention, by adjusting the type and addition amount of the above amine, the surface charge amount of the hollow silica particles can be adjusted to an arbitrary surface charge amount.

[0032] In the present invention, the surface of the hollow silica particles can be coated with a silane compound. The above silane compound can be coated with a hydrolyzate of at least one silane compound selected from the group consisting of formula (1) and formula (2). In formula (1), R 1 each represents an alkyl group, a halogenated alkyl group, an alkenyl group, an aryl group, or a polyether group, an epoxy group, a (meth)acryloyl group, a mercapto group, an amino group, a ureido group, or an organic group having a cyano group and is bonded to a silicon atom by an Si-C bond, and R 2 each represents an alkoxy group, an acyloxy group, or a halogen group, a represents an integer of 1 to 3, In formula (2), R 3 each represents an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms and is bonded to a silicon atom by an Si-C bond, and R 4 each represents an alkoxy group, an acyloxy group, or a halogen group, Y represents an alkylene group, an NH group, or an oxygen atom, b is an integer of 1 to 3, c is an integer of 0 or 1, and d is an integer of 1 to 3.

[0033] The above alkyl group is an alkyl group having 1 to 18 carbon atoms, such as methyl group, ethyl group, n-propyl group, i-propyl group, cyclopropyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, cyclobutyl group, 1-methyl-cyclopropyl group, 2-methyl-cyclopropyl group, n-pentyl group, 1-methyl-n-butyl group, 2-methyl-n-butyl group, 3-methyl-n-butyl group, 1,1-dimethyl-n-propyl group, 1,2-dimethyl-n-propyl group, 2,2-dimethyl-n-propyl group, 1-ethyl-n-propyl group, cyclopentyl group, 1-methyl-cyclobutyl group, 2-methyl-cyclobutyl group, 3-methyl-cyclobutyl group, 1,2-dimethyl-cyclopropyl group, 2,3-dimethyl-cyclopropyl group, 1-ethyl-cyclopropyl group, 2-ethyl-cyclopropyl group, n-hexyl group, 1-methyl-n-pentyl group, 2-methyl-n-pentyl group, 3-methyl-n-pentyl group, 4-methyl-n-pentyl group, 1,1-dimethyl-n-butyl group, 1,2-dimethyl-n-butyl group, 1,3-dimethyl-n-butyl group, 2,2-dimethyl-n-butyl group, 2,3-dimethyl-n-butyl group, 3,3-dimethyl-n-butyl group, 1-ethyl-n-butyl group, 2-ethyl-n-butyl group, 1,1,2-trimethyl-n-propyl group, 1,2,2-trimethyl-n-propyl group, 1-ethyl-1-methyl-n-propyl group, 1-ethyl-2-methyl-n-propyl group, cyclohexyl group, 1-methyl-cyclopentyl group, 2-methyl-cyclopentyl group, 3-methyl-cyclopentyl group, 1-ethyl-cyclobutyl group, 2-ethyl-cyclobutyl group, 3-ethyl-cyclobutyl group, 1,2-dimethyl-cyclobutyl group, 1,3-dimethyl-cyclobutyl group, 2,2-dimethyl-cyclobutyl group, 2,3-dimethyl-cyclobutyl group, 2,4-dimethyl-cyclobutyl group, 3,3-dimethyl-cyclobutyl group, 1-n-propyl-cyclopropyl group, 2-n-propyl-cyclopropyl group, 1-i-propyl-cyclopropyl group, 2-i-propyl-cyclopropyl group, 1,2,2-trimethyl-cyclopropyl group, 1, Examples include, but are not limited to, 2,3-trimethyl-cyclopropyl group, 2,2,3-trimethyl-cyclopropyl group, 1-ethyl-2-methyl-cyclopropyl group, 2-ethyl-1-methyl-cyclopropyl group, 2-ethyl-2-methyl-cyclopropyl group, 2-ethyl-3-methyl-cyclopropyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc. In addition, examples of the alkylene group include alkylene groups derived from the above alkyl groups.

[0034] The above aryl group is an aryl group having 6 to 30 carbon atoms, and examples include phenyl group, naphthyl group, anthracene group, pyrene group, etc. The alkenyl group is an alkenyl group having 2 to 10 carbon atoms, such as ethenyl group, 1-propenyl group, 2-propenyl group, 1-methyl-1-ethenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethyl ethenyl group, 1-methyl-1-propenyl group, 1-methyl-2-propenyl group, 1-pentenyl group, 2-pentenyl group, 3-pentenyl group, 4-pentenyl group, 1-n-propyl ethenyl group, 1-methyl-1-butenyl group, 1-methyl-2-butenyl group, 1-methyl-3-butenyl group, 2-ethyl-2-propenyl group, 2-methyl-1-butenyl group, 2-methyl-2-butenyl group, 2-methyl-3-butenyl group, 3-methyl-1-butenyl group, 3-methyl-2-butenyl group, 3-methyl-3-butenyl group, 1,1-dimethyl-2-propenyl group, 1-i-propyl ethenyl group, 1,2-dimethyl-1-propenyl group, 1,2-dimethyl-2-propenyl group, 1-cyclopentenyl group, 2-cyclopentenyl group, 3-cyclopentenyl group, 1-hexenyl group, 2-hexenyl group, 3-hexenyl group, 4-hexenyl group, 5-hexenyl group, 1-methyl-1-pentenyl group, 1-methyl-2-pentenyl group, 1-methyl-3-pentenyl group, 1-methyl-4-pentenyl group, 1-n-butyl ethenyl group, 2-methyl-1-pentenyl group, 2-methyl-2-pentenyl group, etc., but not limited thereto.

[0035] The above alkoxy group includes an alkoxy group having 1 to 10 carbon atoms, such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, n-pentyloxy group, 1-methyl-n-butoxy group, 2-methyl-n-butoxy group, 3-methyl-n-butoxy group, 1,1-dimethyl-n-propoxy group, 1,2-dimethyl-n-propoxy group, 2,2-dimethyl-n-propoxy group, 1-ethyl-n-propoxy group, n-hexyloxy group, etc., but not limited thereto. The above acyloxy group is an acyloxy group having 2 to 10 carbon atoms, such as methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, i-propylcarbonyloxy group, n-butylcarbonyloxy group, i-butylcarbonyloxy group, s-butylcarbonyloxy group, t-butylcarbonyloxy group, n-pentylcarbonyloxy group, 1-methyl-n-butylcarbonyloxy group, 2-methyl-n-butylcarbonyloxy group, 3-methyl-n-butylcarbonyloxy group, 1,1-dimethyl-n-propylcarbonyloxy group, 1,2-dimethyl-n-propylcarbonyloxy group, 2,2-dimethyl-n-propylcarbonyloxy group, 1-ethyl-n-propylcarbonyloxy group, n-hexylcarbonyloxy group, 1-methyl-n-pentylcarbonyloxy group, 2-methyl-n-pentylcarbonyloxy group, etc., but is not limited thereto. Examples of the above halogen group include fluorine, chlorine, bromine, iodine, etc. Examples of the organic group having a polyether group include a polyetherpropyl group having an alkoxy group. For example, (CH3O)3SiC3H6(OC2H4)nOCH3 can be mentioned. n can be used in the range of 1 to 100, or 1 to 10.

[0036] Examples of the organic group having an epoxy group include 2-(3,4-epoxycyclohexyl)ethyl group, 3-glycidoxypropyl group, etc. The above (meth)acryloyl group represents both an acryloyl group and a methacryloyl group. Examples of the organic group having a (meth)acryloyl group include 3-methacryloxypropyl group, 3-acryloxypropyl group, etc.

[0037] Examples of the organic group having a mercapto group include 3-mercaptopropyl group. Examples of the organic group having an amino group include a 2-aminoethyl group, a 3-aminopropyl group, an N-2-(aminoethyl)-3-aminopropyl group, an N-(1,3-dimethyl-butylidene)aminopropyl group, an N-phenyl-3-aminopropyl group, an N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl group, and the like. Examples of the organic group having a ureido group include a 3-ureidopropyl group. Examples of the organic group having a cyano group include a 3-cyanopropyl group. A compound capable of forming a trimethylsilyl group on the surface of silica particles in the above formula (2) is preferred.

[0038] These compounds can be exemplified as follows.

Chemical formula

[0039] As the coating amount of the above silane compound on the surface of silica particles, a silane compound corresponding to a coating amount of 0.1 silicon atoms / nm 2 to 6.0 silicon atoms / nm 2 can be added to the silica sol to coat the surface of the silica particles. Water is required for the hydrolysis of the above silane compound, but if it is a sol of an aqueous solvent, that water A polar solvent is used. When the aqueous medium is solvent-exchanged with an organic solvent, the water remaining in the solvent can be used. For example, water present in an amount of 0.01 to 1% by mass can be used. Further, hydrolysis can be carried out either with or without a catalyst.

[0040] When carried out without a catalyst, it is a case where the surface of the silica particles is present on the acidic side. When a catalyst is used, examples of the hydrolysis catalyst include metal chelate compounds, organic acids, inorganic acids, organic bases, and inorganic bases. Examples of the metal chelate compound as the hydrolysis catalyst include triethoxy·mono(acetylacetonato)titanium, triethoxy·mono(acetylacetonato)zirconium, and the like. Examples of the organic acid as the hydrolysis catalyst include acetic acid, oxalic acid, and the like. Examples of the inorganic acid as the hydrolysis catalyst include hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, and the like. Examples of the organic base as the hydrolysis catalyst include pyridine, pyrrole, piperazine, and quaternary ammonium salts. Examples of the inorganic base as the hydrolysis catalyst include ammonia, sodium hydroxide, and potassium hydroxide. The organic acid is at least one organic acid selected from the group consisting of divalent aliphatic carboxylic acids, aliphatic oxycarboxylic acids, amino acids, and chelating agents. The divalent aliphatic carboxylic acids are oxalic acid, malonic acid, and succinic acid. The aliphatic oxycarboxylic acids are glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid. The amino acids are glycine, alanine, valine, leucine, serine, and threonine. Examples of the chelating agent include ethylenediaminetetraacetic acid, L-aspartic acid-N,N-diacetic acid, and diethylenetriaminepentaacetic acid. Examples of the organic acid salts include alkali metal salts, ammonium salts, and amine salts of the above organic acids. Examples of the alkali metals include sodium and potassium.

[0041] In the present invention, a film-forming composition containing the above hollow silica organic solvent sol and an organic resin or polysiloxane is obtained. An organic resin or polysiloxane is selected and mixed with a thermosetting or photocurable resin to obtain a film-forming composition. And it can be made into a cured product by including a curing agent such as an amine-based curing agent, an acid anhydride-based curing agent, a radical generator-based curing agent (thermal radical generator, photo radical generator), or an acid generator-based curing agent (thermal acid generator, or photo acid generator). This composition can form a cured product by applying or filling a film-forming composition containing an organic resin or polysiloxane and a curing agent to a substrate and curing it by heating, light irradiation, or a combination thereof. Examples of the organic resin and polysiloxane (curable resin) include resins having functional groups such as epoxy groups or (meth)acryloyl groups, and isocyanate-based resins. For example, a photocurable polyfunctional acrylate can be preferably used.

[0042] Examples of the polyfunctional acrylate include polyfunctional acrylates having bifunctional, trifunctional, tetrafunctional, or more functional groups in the molecule, such as neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like. These polyfunctional acrylates can also be described below.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0043] The film-forming composition of the present invention can contain a surfactant (leveling agent). As the surfactant (leveling agent), anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, and silicone-based surfactants can be used. The surfactant (leveling agent) can be added in the range of 0.01 to 5 phr, or 0.01 to 1 phr, with respect to the organic resin or polysiloxane. Examples of the anionic surfactant used in the present invention include sodium salts and potassium salts of fatty acids, alkylbenzene sulfonates, higher alcohol sulfates, polyoxyethylene alkyl ether sulfates, α-sulfo fatty acid esters, α-olefin sulfonates, monoalkyl phosphate esters, and alkane sulfonates. For example, alkylbenzene sulfonates include sodium salts, potassium salts, and lithium salts, such as sodium C10-C16 alkylbenzene sulfonate, C10-C16 alkylbenzene sulfonic acid, and sodium alkylnaphthalene sulfonate.

[0044] Examples of the higher alcohol sulfate include sodium dodecyl sulfate (sodium lauryl sulfate) having 12 carbon atoms, triethanolamine lauryl sulfate, and triethanolammonium lauryl sulfate. Examples of the polyoxyethylene alkyl ether sulfate include sodium polyoxyethylene styrenated phenyl ether sulfate, ammonium polyoxyethylene styrenated phenyl ether sulfate, sodium polyoxyethylene decyl ether sulfate, ammonium polyoxyethylene decyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, ammonium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene tridecyl ether sulfate, and sodium polyoxyethylene oleyl cetyl ether sulfate. Examples of the α-olefin sulfonate include sodium α-olefin sulfonate.

[0045] Examples of the alkane sulfonate include sodium 2-ethylhexyl sulfate. The cationic surfactants used in the present invention include, for example, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, and amine salt-based agents. The alkyltrimethylammonium salt is a quaternary ammonium salt and has chloride ions or bromide ions as counterions. For example, dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, coconut alkyltrimethylammonium chloride, alkyl (C16-18) trimethylammonium chloride, etc. can be mentioned. The dialkyldimethylammonium salt has two lipophilic main chains and two methyl groups. Bis (hydrogenated tallow) dimethylammonium chloride can be mentioned. For example, didecyldimethylammonium chloride, di-coconut alkyl dimethylammonium chloride, di-hardened tallow alkyl dimethylammonium chloride, dialkyl (C14-18) dimethylammonium chloride, etc. can be mentioned.

[0046] The alkyldimethylbenzylammonium salt is a quaternary ammonium salt having one lipophilic main chain, two methyl groups, and a benzyl group, and benzalkonium chloride can be mentioned. For example, alkyl (C8-18) dimethylbenzylammonium chloride can be mentioned. The amine salt-based agent is one in which one or more hydrogen atoms of ammonia are substituted with hydrocarbon groups, and for example, N-methylbis-hydroxyethylamine fatty acid ester hydrochloride can be mentioned. The amphoteric surfactants used in the present invention include N-alkyl-β-alanine type alkylaminocarboxylates, alkyl carboxybetaine type alkylbetaines, and N,N-dimethyldodecylamine oxide type alkylamine oxides. Examples thereof include lauryl betaine, stearyl betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, and lauryldimethylamine oxide.

[0047] The nonionic surfactant used in the present invention is selected from polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, alkyl glucosides, polyoxyethylene fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and fatty acid alkanolamides. For example, poly Examples of polyoxyethylene alkyl ethers include polyoxyethylene dodecyl ether (polyoxyethylene lauryl ether), polyoxyalkylene lauryl ether, polyoxyethylene tridecyl ether, polyoxyalkylene tridecyl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene isodecyl ether, and the like. Examples of polyoxyethylene alkylphenol ethers include polyoxyethylene styrenated phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene tribenzylphenyl ether, and the like.

[0048] Examples of alkyl glucosides include decyl glucoside, lauryl glucoside, and the like. Examples of polyoxyethylene fatty acid esters include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol dioleate, polypropylene glycol dioleate, and the like. Examples of sorbitan fatty acid esters include sorbitan monocaprylate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan monoesquioleate, and ethylene oxide adducts thereof.

[0049] Examples of polyoxyethylene sorbitan fatty acid esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan triisostearate, and the like. Examples of fatty acid alkanolamides include coconut fatty acid diethanolamide, tallow fatty acid diethanolamide, lauric acid diethanolamide, oleic acid diethanolamide, and the like.

[0050] Furthermore, polyoxyalkyl ethers or polyoxyalkyl glycols such as polyoxyethylene polyoxypropylene glycol and polyoxyethylene fatty acid esters, polyoxyethylene hydrogenated castor oil ether, sorbitan fatty acid ester alkyl ether, alkyl polyglucoside, sorbitan monooleate, sucrose fatty acid ester, and the like can be mentioned. A silicone surfactant can be used. The silicone surfactant is a compound having a repeating unit containing a siloxane bond in the main chain. The weight average molecular weight of the silicone surfactant can be used in the range of 500 to 50,000. These may be modified silicone surfactants, and examples include structures in which an organic group is introduced into the side chain and / or the terminal of polysiloxane. Examples of the organic group include an amino group, an epoxy group, an alicyclic epoxy group, a carbinol group, a mercapto group, a carboxyl group, an aliphatic ester group, an aliphatic amide group, and a polyether group. Examples of the silicone surfactant include trade names, Toray Silicone DC3PA, Toray Silicone SH7PA, Toray Silicone DC11PA, Toray Silicone SH21PA, Toray Silicone SH28PA, Toray Silicone SH29PA, Toray Silicone SH30PA, Toray Silicone SH8400 (above, manufactured by Toray Dow Corning Co., Ltd.), Silwet l-77, L-7280, L-7001, L-7002, L-7200, L-7210, L-7220, L-7230, L7500, L-7600, L-7602, L-7604, L-7605, L-7622, L-765 7, L-8500, L-86 10 (above, manufactured by Momentive Performance Materials), KP-341, KF-6001, KF-6002 (above, manufactured by Shin-Etsu Silicone Co., Ltd.), BYK307, BYK323, BYK330 (above, manufactured by BYK Chemie) and the like. For example, the trade name L-7001 (manufactured by DOWSIL) can be preferably used as the polyether-modified silicone.

[0051] In the present invention, a film-forming composition containing the above organic solvent sol and an organic resin or polysiloxane is obtained. The film-forming composition can be obtained by removing the organic solvent in the organic solvent sol to obtain a film-forming composition containing hollow silica particles and an organic resin. In the case of a thermosetting film-forming composition in the above film-forming composition, a curing agent can be added to a functional group-containing resin such as an epoxy group or a (meth)acryloyl group in the range of 0.01 to 50 phr, or 0.01 to 10 phr. For example, the curing agent can be contained in a proportion of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, relative to a functional group such as an epoxy group or a (meth)acryloyl group. The equivalent amount of the curing agent relative to the curable resin is indicated by the equivalent ratio of the curing agent relative to the functional group.

[0052] Examples of the curing agent include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polymercaptans, acid anhydrides, thermal radical generators, thermal acid generators, etc. Particularly, radical generator-based curing agents, acid anhydride-based curing agents, and amine-based curing agents are preferred. These curing agents can be used by dissolving them in a solvent even if they are solid. However, since evaporation of the solvent causes a decrease in the density of the cured product, a decrease in strength due to the formation of pores, and a decrease in water resistance, it is preferable that the curing agent itself is liquid at normal temperature and normal pressure. Examples of the phenolic resin include phenol novolac resin, cresol novolac resin, etc.

[0053] Examples of amine-based curing agents include piperidine, N,N-dimethylpiperazine, triethylenediamine, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, menthanediamine, isophoronediamine, diaminodicyclohexylmethane, 1,3-diaminomethylcyclohexane, xylylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, 3,3'-diethyl-4,4'-diaminodiphenylmethane, diethyltoluenediamine, and the like. Among these, liquid diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, di(1-methyl-2-aminocyclohexyl)methane, menthanediamine, isophoronediamine, diaminodicyclohexylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, diethyltoluenediamine, and the like can be preferably used. The polyamide resin is produced by the condensation of dimer acid and polyamine, and is a polyamideamine having a primary amine and a secondary amine in the molecule.

[0054] Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, epoxyimidazole adduct, and the like. The polymercaptan is, for example, one having a mercapto group at the end of a polypropylene glycol chain or one having a mercapto group at the end of a polyethylene glycol chain, and a liquid one is preferred.

[0055] The acid anhydride-based curing agent is an anhydride of a compound having a plurality of carboxyl groups in one molecule Preferred. Examples of these acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, ethylene glycol bistrimellitate, glycerol tristrimellitate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylcyclohexene dicarboxylic anhydride, chlorendic anhydride, and the like. Examples of the thermal acid generator include sulfonium salts and phosphonium salts, and sulfonium salts are preferably used. For example, the following compounds can be exemplified. [Chemical formula] R includes an alkyl group having 1 to 12 carbon atoms and an aryl group having 6 to 20 carbon atoms, and an alkyl group having 1 to 12 carbon atoms is particularly preferred.

[0056] Among these, methyltetrahydrophthalic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride (methyl nadic anhydride, anhydrous methyl hymic acid), hydrogenated methyl nadic anhydride, methylbutenyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, methylhexahydrophthalic anhydride, and a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, which are liquid at normal temperature and pressure, are preferred. These liquid acid anhydrides have a viscosity of about 10 mPa·s to 1000 mPa·s as measured at 25°C. Examples of the thermal radical generator include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, tert-butyl hydroperoxide, cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, benzoyl peroxide, etc. These can be obtained from Tokyo Chemical Industry Co., Ltd.

[0057] Also, when obtaining the above-mentioned cured product, a curing aid may be appropriately used in combination. Examples of the curing aid include organic phosphorus compounds such as triphenylphosphine and tributylphosphine, quaternary phosphonium salts such as ethyltriphenylphosphonium bromide and diethyl methyltriphenylphosphonium phosphate, 1,8-diazabicyclo(5,4,0)undec-7-ene, a salt of 1,8-diazabicyclo(5,4,0)undec-7-ene and octylic acid, zinc octylate, quaternary ammonium salts such as tetrabutylammonium bromide. These curing aids can be contained in a proportion of 0.001 to 0.1 parts by mass with respect to 1 part by mass of the curing agent. The composition can be obtained by mixing a resin, a curing agent, and, if desired, a curing aid to obtain a thermosetting varnish. These mixtures can be carried out using a stirring blade or a kneader in a reaction vessel.

[0058] The mixing is carried out by a heat mixing method and is carried out at a temperature of 60°C to 100°C for 0.5 to 1 hour. 。 The obtained curable film-forming composition is a thermosetting coating composition and has an appropriate viscosity for use, for example, as a liquid encapsulant. The liquid thermosetting film-forming composition can be adjusted to any viscosity and can be partially encapsulated at any position thereof for use as a transparent encapsulant for LEDs or the like by a casting method, a potting method, a dispenser method, a printing method, or the like. After the liquid thermosetting composition is directly mounted on an LED or the like in a liquid state by the above-described method and then dried and cured, a cured epoxy resin is obtained. The thermosetting film-forming composition (thermosetting coating composition) is applied to a substrate and cured by heating at a temperature of 80 to 200 °C to obtain a cured product. In the case of a photocurable resin composition in the above film-forming composition, a photoinitiator (photo radical generator, photoacid generator) can be added in the range of 0.01 to 50 phr, or 0.01 to 10 phr, to a resin containing a functional group such as an epoxy group or a (meth)acryloyl group. For example, the photoinitiator (photo radical generator, photoacid generator) can be contained at a ratio of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, relative to a functional group such as an epoxy group or a (meth)acryloyl group. The equivalent of the photoinitiator relative to the curable resin is represented by the equivalent ratio of the photoinitiator relative to the functional group. The photo radical generator is not particularly limited as long as it can generate radicals directly or indirectly by light irradiation.

[0059] As the photo radical generator, examples of the photo radical polymerization initiator include imidazole compounds, diazo compounds, bisimidazole compounds, N-aryl glycine compounds, organic azide compounds, titanocene compounds, aluminato compounds, organic peroxides, N-alkoxypyridinium salt compounds, and thioxanthone compounds. Examples of the azide compound include p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, 4,4'-diazidochalcone, 4,4'-diazidodiphenyl sulfide, and 2,6-bis(4'-azidobenzal)-4-methylcyclohexanone. Examples of the diazo compound include 1-diazo-4-N,N-dimethylaminobenzene chloride and 1-diazo-4-N,N-diethylaminobenzene borofluoride. Examples of the bisimidazole compound include 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)1,2'-bisimidazole and 2,2'-bis(o-chlorophenyl)4,5,4',5'-tetraphenyl-1,2'-bisimidazole. Examples of the titanocene compound include dicyclopentadienyl-titanium-dichloride, dicyclopentadienyl-titanium-bisphenyl, dicyclopentadienyl-titanium-bis(2,3,4,5,6-pentafluorophenyl), dicyclopentadienyl-titanium-bis(2,3,5,6-tetrafluorophenyl), dicyclopentadienyl-titanium-bis(2,4,6-trifluorophenyl), dicyclopentadienyl-titanium-bis(2,6-difluorophenyl), dicyclopentadienyl-titanium-bis(2,4-difluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,3,4,5,6-pentafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,3,5,6-tetrafluorophenyl), bis(methylcyclopentadienyl)-titanium-bis(2,6-difluorophenyl), and dicyclopentadienyl-titanium-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl).

[0060] Examples of the photo radical generator also include 1,3-di(tert-butyldioxycarbonyl)benzophenone, 3,3',4,4'-tetrakis(tert-butyldioxycarbonyl)benzophenone, 3-phenyl-5-isoxazolone, 2-mercaptobenzimidazole, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)-butanone and the like. These photo radical polymerization agents can be obtained, for example, under the trade name IrgacureTPO (the component is 2,4,6-trimethylbenzoyldiphenylphosphine oxide) (formula (c1-1-1)) manufactured by BASF, under the trade name Omnirad819 (the component is bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) (formula (c1-1-2)) manufactured by IGM RESINS, and under the trade name Irgacure 184 (the component is 1-hydroxycyclohexylphenylketone) (formula (c1-1-3)) manufactured by IGM RESINS. [Chemical formula]

[0061] The photoacid generator is not particularly limited as long as it can generate an acid directly or indirectly by light irradiation. Specific examples of the photoacid generator include triazine compounds, acetophenone derivative compounds, disulfone compounds, diazomethane compounds, sulfonic acid derivative compounds, onium salts such as iodonium salts, sulfonium salts, phosphonium salts, and selenium salts, metallocene complexes, iron arene complexes, and the like.

[0062] The onium salts used as the above photoacid generator include, as iodonium salts, for example, diphenyliodonium chloride, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium mesylate, diphenyliodonium tosylate, diphenyliod Nium bromide, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsenate, bis(p-tert-butylphenyl)iodonium hexafluorophosphate, bis(p-tert-butylphenyl)iodonium mesylate, bis(p-tert-butylphenyl)iodonium tosylate, bis(p-tert-butylphenyl)iodonium trifluoromethanesulfonate, bis(p-tert-butylphenyl)iodonium tetrafluoroborate, bis(p-tert-butylphenyl)iodonium chloride, bis(p-chlorophenyl)iodonium chloride, bis(p-chlorophenyl)iodonium tetrafluoroborate, and further bis(alkylphenyl)iodonium salts such as bis(4-t-butylphenyl)iodonium hexafluorophosphate, alkoxycarbonylalkoxy-trialkylaryliodonium salts (for example, 4-[(1-ethoxycarbonyl-ethoxy)phenyl]-(2,4,6-trimethylphenyl)-iodonium hexafluorophosphate, etc.), bis(alkoxyaryl)iodonium salts (for example, bis(alkoxyphenyl)iodonium salts such as (4-methoxyphenyl)phenyliodonium hexafluoroantimonate, etc.).

[0063] Triphenylsulfonium salts such as triphenylsulfonium chloride, triphenylsulfonium bromide, tri(p-methoxyphenyl)sulfonium tetrafluoroborate, tri(p-methoxyphenyl)sulfonium hexafluorophosphate, tri(p-ethoxyphenyl)sulfonium tetrafluoroborate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, etc., and sulfonium salts such as (4-phenylthiophenyl)diphenylsulfonium hexafluoroantimonate, (4 - phenylthiophenyl)diphenylsulfonium hexafluorophosphate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluoroantimonate, bis[4-(diphenylsulfonio)phenyl]sulfide-bis-hexafluorophosphate, (4-methoxyphenyl)diphenylsulfonium hexafluoroantimonate) are exemplified.

[0064] Phosphonium salts such as triphenylphosphonium chloride, triphenylphosphonium bromide, tri(p-methoxyphenyl)phosphonium tetrafluoroborate, tri(p-methoxyphenyl)phosphonium hexafluorophosphate, tri(p-ethoxyphenyl)phosphonium tetrafluoroborate, 4-chlorobenzenediazonium hexafluorophosphate, benzyltriphenylphosphonium hexafluoroantimonate, etc., are exemplified. Selenium salts such as triphenylselenium hexafluorophosphate, and metallocene complexes such as (η5 or η6-isopropylbenzene)(η5-cyclopentadienyl)iron(II) hexafluorophosphate are exemplified.

[0065] In addition, the following compounds can also be used as photoacid generators.

Chemical formula

Chemical formula

[0066]

Chem.

Chem.

[0067]

Chem.

Chem.

[0068]

Chem.

Chem.

Chem.

[0069] As sulfonium salt compounds and iodonium salt compounds are preferred as photoacid generators. As their anion species, CF3SO3 - , C4F9SO3 - , C8F 17 SO3 - , camphorsulfonic acid anion, tosylate anion, BF4 - , PF6 - , AsF6 - and SbF6 - etc. can be mentioned. Anion species such as phosphorus hexafluoride and antimony hexafluoride showing particularly strong acidity are preferred. The film-forming composition of the present invention may contain conventional additives as necessary. Such Examples of additives include pigments, colorants, thickeners, sensitizers, defoamers, coating property improvers, lubricants, stabilizers (such as antioxidants, heat stabilizers, and light stabilizers), plasticizers, dissolution accelerators, fillers, antistatic agents, and the like. These additives may be used alone or in combination of two or more. Examples of the coating method of the film-forming composition of the present invention include a flow coating method, a spin coating method, a spray coating method, a screen printing method, a casting method, a bar coating method, a curtain coating method, a roll coating method, a gravure coating method, a dipping method, a slit method, and the like.

[0070] In the present invention, the photocurable coating composition (film-forming composition) can be applied onto a substrate and cured by light irradiation. Further, heating can also be performed before and after the light irradiation. The thickness of the coating film can be selected from the range of about 0.01 μm to 10 mm according to the use of the cured product. For example, when used for a photoresist, it can be about 0.05 to 10 μm (particularly 0.1 to 5 μm); when used for a printed wiring board, it can be about 5 μm to 5 mm (particularly 100 μm to 1 mm); and when used for an optical thin film, it can be about 0.1 to 100 μm (particularly 0.3 to 50 μm). When obtaining a transparent film, the visible light transmittance of the film can be 80% or more, or 90% or more, typically 90 to 96%.

[0071] The light for irradiation or exposure when using a photoacid generator may be, for example, gamma rays, X-rays, ultraviolet rays, visible light, etc., and usually visible light or ultraviolet rays, particularly ultraviolet rays in many cases. The wavelength of the light is, for example, about 150 to 800 nm, preferably 150 to 600 nm, more preferably about 150 to 400 nm. The irradiation light amount varies depending on the thickness of the coating film, but for example, it is 2 to 20000 mJ / cm 2 , preferably 5 to 5000 mJ / cm 2It can be adjusted accordingly. The light source can be selected according to the type of light rays for exposure. For example, in the case of ultraviolet rays, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a deuterium lamp, a halogen lamp, a laser beam (such as a helium-cadmium laser, an excimer laser, etc.) can be used. Through such light irradiation, the curing reaction of the composition proceeds. When using a thermal acid generator or when using a photoacid generator and heating the coating film if necessary after light irradiation, it is carried out, for example, at about 60 to 350 °C, preferably about 100 to 300 °C. The heating time can be selected from the range of 3 seconds or more (for example, about 3 seconds to 5 hours), for example, it can be carried out for 5 seconds to 2 hours, preferably about 20 seconds to 30 minutes, and usually it can be carried out for about 1 minute to 3 hours (for example, 5 minutes to 2.5 hours).

[0072] Furthermore, when forming a pattern or an image (for example, when manufacturing a printed wiring board, etc.), the coating film formed on the substrate may be pattern-exposed. This pattern exposure may be carried out by scanning with a laser beam or by irradiating light through a photomask. By developing (or dissolving) the non-irradiated region (unexposed portion) generated by such pattern exposure with a developer, a pattern or an image can be formed. As the developer, an aqueous alkali solution or an organic solvent can be used. Examples of the aqueous alkali solution include aqueous solutions of alkali metal hydroxides such as potassium hydroxide, sodium hydroxide, potassium carbonate, and sodium carbonate, aqueous solutions of quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline, and amine aqueous solutions such as ethanolamine, propylamine, and ethylenediamine.

[0073] The alkali developer is generally an aqueous solution of 10 mass% or less, and preferably an aqueous solution of 0.1 to 3.0 mass% is used. Furthermore, alcohols or surfactants can also be added to the above developer and used. These are preferably 0.05 to 10 mass parts with respect to 100 mass parts of the developer. Among these, an aqueous solution of tetramethylammonium hydroxide with a concentration of 0.1 to 2.38% by mass can be used. This is achievable. In addition, as the organic solvent for the developer, a general organic solvent can be used. For example, acetone, acetonitrile, toluene, dimethylformamide, methanol, ethanol, isopropanol, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol butyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol butyl ether acetate, ethyl lactate, cyclohexanone, etc. can be mentioned, and these can be used as a mixture of one or more of them. In particular, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl lactate, etc. can be preferably used.

[0074] In the present invention, an adhesion promoter can be added for the purpose of improving the adhesion to the substrate after development. These adhesion promoters include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, chloromethyldimethylchlorosilane, etc., alkoxysilanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, etc., silazanes such as hexamethyldisilazane, N,N'-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, trimethylsilylimidazole, etc., silanes such as vinyltrichlorosilane, 3-chloropropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-(N-piperidinyl)propyltrimethoxysilane, etc., heterocyclic compounds such as benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, urazole, thiouracil, mercaptoimidazole, mercaptopyrimidine, etc., ureas such as 1,1-dimethylurea, 1,3-dimethylurea, or thiourea compounds. One or more of the above adhesion promoters can be used in combination. The addition amount of these adhesion promoters in the solid content is usually 18% by mass or less, preferably 0.0008 to 9% by mass, more preferably 0.04 to 9% by mass.

[0075] The present invention may contain a sensitizer. Examples of the sensitizer that can be used include anthracene, phenothiazine, perylene, thioxanthone, benzophenone thioxanthone, and the like. Further, examples of the sensitizing dye include thiopyrylium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, pyrylium salt dyes, and the like. Particularly preferred is an anthracene-based sensitizer. When used in combination with a cationic curing catalyst (photo-sensitive cationic polymerization initiator), the sensitivity is dramatically improved, and it also has a radical polymerization initiation function. In the hybrid type that combines the cationic curing system and the radical curing system of the present invention, the catalyst species can be simplified. Specific anthracene compounds such as dibutoxyanthracene and dipropoxyanthraquinone are effective. The addition amount of the sensitizer is used in a proportion of 0.01 to 20% by mass, preferably 0.01 to 10% by mass in the solid content. The composition of the present invention can be photocured or thermally cured using a photo radical generator, a thermal radical generator, a photoacid generator, or a thermal acid generator. When using a photoacid generator or a thermal acid generator, for example, a commonly used epoxy curing agent (such as an amine or an acid anhydride) is not used or, even if used, their contents are extremely low, so the storage stability of this composition is improved.

[0076] It has been found that the above composition is applicable to photocationic polymerization. It has a higher curing rate than conventional liquid epoxy compounds (for example, alicyclic epoxy compounds having an epoxycyclohexyl ring). Since the curing rate is high, it is possible to reduce the addition amount of the acid generator and use a weak acid-based acid generator. The reduction of the acid generator is important for preventing metal corrosion because acid active species may remain after UV irradiation. Since the curing rate is high, thick film curing is possible. Curing by UV irradiation can be applied to materials (equipment) that are vulnerable to heat. The thermosetting materials and photocuring materials using the film-forming composition of the present invention have characteristics such as low dielectric constant, low dielectric tangent, rapid hardening, high transparency, and small curing shrinkage, and can be used for coating and adhesion of electronic components, optical components (antireflection films), and precision mechanical components. For example, optical elements such as lenses of mobile phones and cameras, light-emitting diodes (LEDs), semiconductor lasers (LDs), liquid crystal panels, biochips, components such as lenses and prisms of cameras, magnetic components of hard disks of personal computers, pickups of CD and DVD players (parts that capture optical information reflected from the disk), cones and coils of speakers, magnets of motors, circuit boards, electronic components, components inside engines of automobiles, etc. can be used for adhesion.

[0077] For the hard coat materials for surface protection of automobile bodies, lamps, household appliances, building materials, plastics, etc., for example, it can be applied to automobile and motorcycle bodies, lenses and mirrors of headlights, plastic lenses of glasses, mobile phones, game machines, optical films, ID cards, etc. For the ink materials for printing on metals such as aluminum and plastics, applications include inks for printing on cards such as credit cards and membership cards, switches of household appliances and OA equipment, keyboards, and inks for inkjet printers on CDs, DVDs, etc. Applications include technologies for curing resins in combination with 3D CAD to create complex three-dimensional objects, applications to stereolithography for model making of industrial products, coating, adhesion, optical waveguides, thick film resists, etc. of optical fibers.

[0078] In addition, the film-forming composition of the present invention can be suitably used as an insulating resin for electronic materials such as antireflection films, semiconductor encapsulation materials, adhesives for electronic materials, printed wiring board materials, interlayer insulating film materials, buffer coating agents for semiconductors, enamel insulating materials, encapsulation materials for power modules, etc., and insulating resins used in high-voltage equipment such as generator coils, transformer coils, and gas-insulated switchgear. The hollow silica sol of the present invention can be manufactured including the following steps (I) to (II). (I) Step: A step of preparing hollow silica sol (II) Process: In the hollow silica sol of the (I) process, the monovalent alkali metal ions are adjusted to a molar ratio of 7.12×10 -6 ~285×10 -6 with respect to SiO₂ of the hollow silica particles, and a hollow silica sol can be obtained through this process. In the above (II) process, it is preferable to use sodium ions as the monovalent alkali metal ions. In the above (II) process, the adjustment of the sodium ion content can be achieved by contacting the hollow silica sol obtained in the (I) process with a cation exchange resin or by adding a sodium source. In the above (II) process, it is preferable that the added sodium source is sodium hydroxide and it is added as an aqueous sodium hydroxide solution. For the dispersion media in the (I) process and the (II) process, water, an alcohol having 1 to 10 carbon atoms, a ketone, an ether, an amide, a urea, or an ester can be used. These dispersion media can be exemplified by the above solvents.

[0079] In the present invention, at least one step selected from the following (i) to (iv) can be added in the above (I) process, (II) process, or both processes. (i): Adding an amine to the hollow silica sol, (ii): Adding sodium aluminate as an aluminum source and heating to form aluminosilicate sites on the hollow silica particles, (iii): Replacing the dispersion medium with another dispersion medium, (iv): Coating the hollow silica particles with at least one silane compound selected from the group consisting of formula (1) and formula (2). And in the present invention, in the hollow silica sol having a value of the dynamic light scattering method particle size increased compared to the particle size measured by the dynamic light scattering method during production, the monovalent alkali metal ions are adjusted to a molar ratio of 7.12×10 -6 ~285×10 -6It is possible to provide a method for stabilizing a hollow silica sol containing hollow silica particles having a space inside the outer shell by adding at a ratio of and reducing the increased dynamic light scattering method particle size value. In the above stabilization method, a monovalent alkali metal ion can use sodium ion.

[0080] (ii) The hollow silica sol in the step is a step of adding an aluminum compound at 0.0001 to 0.5 g per 1 g of the hollow silica particles to an aqueous sol and heating at 40 to 260 ° C for 0.1 to 24 hours. The addition amount of the aluminum compound per 1 g of the hollow silica particles in the (ii) step can be added in the range of 0.0001 to 0.5 g, or 0.001 to 0.1 g, or 0.001 to 0.05 g. And the heating temperature in the (ii) step is 40 to 260 ° C, or 50 to 260 ° C, or 60 to 240 ° C, but in the case of non-hydrothermal treatment, it is used at less than 40 to 100 ° C, or less than 50 to 100 ° C, or less than 60 to 100 ° C, and in the case of hydrothermal treatment, it can be carried out at 100 to 260 ° C, or 150 to 240 ° C. The heating time in the (ii) step can be carried out in the range of 0.1 to 48 hours, or 0.1 to 24 hours, or 0.1 to 10 hours, or 1 to 10 hours.

[0081] (I) The hollow silica particles used in the step have a silica outer shell and have a space inside the outer shell. Hollow silica is obtained by a method of forming an outer shell mainly composed of silica on the surface of a portion corresponding to a core called a so-called template in an aqueous dispersion medium and removing the portion corresponding to the core. The above template includes a method using an organic substance (for example, hydrophilic organic resin particles such as polyethylene glycol, polystyrene, polyester, etc.) and a method using an inorganic substance (for example, hydrophilic inorganic compound particles such as calcium carbonate, sodium aluminate, etc.). (I) The hollow silica aqueous sol used as a raw material in the step can use a non-hydrothermally treated hollow silica aqueous sol that has passed through a heating temperature of less than 100 ° C, for example, less than 20 to 100 ° C, or less than 40 to 100 ° C, or less than 50 to 100 ° C in an aqueous medium. In addition, as the hollow silica aqueous sol used in the (I) step, a hydrothermally treated hollow silica aqueous sol that has undergone a heating temperature of 100°C to 240°C, or 110 to 240°C in an aqueous medium can be used.

[0082] As the raw material hollow silica sol used in the present invention, a non-hydrothermally treated hollow silica aqueous sol, a hydrothermally treated hollow silica aqueous sol, or a mixture thereof can be used. This forms aluminosilicate sites on the outer shell of the hollow silica particles. Since the aluminosilicate sites may hold alkali metals, when measuring the aluminum atoms by the leaching method, the raw material hollow silica sol can be selected in terms of binding at 100 to 20000 ppm / SiO2 in terms of Al2O3 relative to the mass of SiO2 of the hollow silica particles on the surface of the hollow silica particles. In the (ii) step, an aluminum compound is added to the hollow silica aqueous sol. The aluminum compound can be added to the hollow silica aqueous sol in a solid form or in the form of an aqueous solution. The aluminum compound used in the (ii) step is at least one aluminum compound selected from the group consisting of aluminates, aluminum alkoxides, and their hydrolyzates, and can be used as an aqueous solution containing them. Examples of aluminates include sodium aluminate, potassium aluminate, calcium aluminate, magnesium aluminate, ammonium aluminate, amine salts of aluminate, etc. Examples of aluminum alk oxides include aluminum isopropoxide, aluminum butoxide, etc. In particular, aluminates can be preferably used.

[0083] These aluminum compounds are added to the hollow silica aqueous sol obtained in the (I) step in the form of an aqueous solution. The concentration of the aqueous solution of the aluminum compound is used in the range of 0.01 to 20% by mass, or 0.1 to 10% by mass, or 0.5 to 5% by mass. The addition can be carried out under stirring of the hollow silica aqueous sol obtained in the (I) step. The addition time can be completed before heating, or can be added over the entire heating time. The impregnation of the hollow silica particles with the desired amount of the aluminum compound depends on the treatment temperature in step (ii), and it is necessary to perform the heat treatment within the above temperature range. Step (i) may further include a step of adding an amine. The amine can be the above-mentioned amine and can be contained in the hollow silica sol within the above range.

[0084] After the above step (ii) performs the heat treatment by adding at least one additive composed of the above aluminum compound, or the above aluminum compound, amine and neutral salt, it can include a step of contacting with a cation exchange resin, a step of adding an acid, or a combination thereof. The cation exchange resin is an H-type strongly acidic cation exchange resin, and it can also be contacted with an anion exchange resin thereafter. As the acid, inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid, or organic acids such as citric acid, acetic acid, malic acid, lactic acid, succinic acid, tartaric acid, butyric acid, fumaric acid, propionic acid, and formic acid can be added. In the present invention, in step (ii), after adding the above aluminum compound (for example, sodium aluminate) and performing heat treatment at 100 to 240 ° C for 0.1 to 48 hours, an acid (for example, sulfuric acid, nitric acid, hydrochloric acid) can be added and a step of contacting with a cation exchange resin can be performed. The addition of the above acid is a leaching operation that elutes the aluminum-containing components not doped into the particles by the heat treatment and the metal impurities contained in the particles into the liquid, and is an operation of removing these metal-containing components with a cation exchange resin. After further heat aging at 40 to 100 ° C for 0.1 to 48 hours, a step of contacting with a cation exchange resin again can be performed.

[0085] As step (iii), a step of further solvent-exchanging the aqueous medium of the aqueous sol of hollow silica with an alcohol, ketone, ether, or ester having 1 to 10 carbon atoms Furthermore, it can include a step (iv) of adding at least one silane compound selected from the group consisting of the above formulas (1) and (2) and heating. After the above step (iii) and step (iv), after the solvent substitution with an alcohol having 1 to 10 carbon atoms in step (iii) after the completion of the above step (ii), at least one silane compound selected from the group consisting of the above formula (1) and formula (2) is added in step (iv), and after heating, it can be a step of further substituting the solvent with a ketone, ether, amide, urea, or ester having 1 to 10 carbon atoms. By using the method for producing the hollow silica sol, the surface charge of the hollow silica particles contained in the sol can be adjusted.

Examples

[0086] Hereinafter, examples and comparative examples will be shown to explain the present invention in more detail, but the present invention is not limited to the following examples. The hollow silica sols used in the examples and comparative examples are as follows.

[0087] [Hollow silica sol] Water-dispersed hollow silica sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40D, the hollow silica aqueous sol is one that has passed through a heating temperature of 100 ° C to 240 ° C in an aqueous medium, pH 9.3, particle size by dynamic light scattering method 55 nm, average primary particle size by TEM observation: 43 nm, TEM-converted specific surface area (D) 63 m 2 / g, specific surface area ratio (C / D ratio) is 2.4, shi lica concentration 20% by mass, contained Na amount: 14 ppm / SiO2, that is, the contained Na2O amount is 6.64×10 as the molar ratio of Na2O to SiO2 -6 mol / SiO2)

[0088] [Basic compound] Aqueous sodium hydroxide solution (Kanto Chemical Co., Inc., trade name: 4 mol / L sodium hydroxide solution) Diethanolamine (Tokyo Chemical Industry Co., Ltd., trade name: Diethanolamine) According to the following method, the physical properties of the water-dispersed hollow silica sol, the dispersion liquids of the silica particles prepared in the examples and comparative examples, and the hollow silica sol and the dispersion liquid during the dispersion liquid production process were measured and evaluated.

[0089] [Measurement of silica (SiO2) concentration] The silica concentration of the aqueous dispersion hollow silica sol, the methanol dispersion hollow silica sol, the hollow silica sol during the production process of the methanol dispersion hollow silica sol, and the dispersion of the surface-modified silica particles was calculated by weighing the calcination residue after removing the solvent by heating the hollow silica sol or dispersion in a crucible and then calcining at 1000 °C.

[0090] [Measurement of pH] Measurement was performed at 25 °C using a pH meter (manufactured by Toa DKK Corporation, product name: MM-43X). For organic solvents that can be arbitrarily mixed with water, such as methanol sol and propylene glycol monomethyl ether sol, measurement was performed on a solution obtained by mixing pure water and the sol at a mass ratio of 1:1. For organic solvent sols with low solubility in water, such as methyl ethyl ketone sol, measurement was performed on a solution obtained by mixing pure water, methanol, and the organic solvent sol at a mass ratio of 1:1:1.

[0091] [Measurement of water content] The water content of the organic solvent dispersion sol was measured by the Karl Fischer titration method.

[0092] [Analysis method for Na content] 0.2 g of the powder obtained by drying the hollow silica sol was treated with 20 mL of a 48 mass% hydrofluoric acid solution to remove the silica component, and the residue was dissolved in 20 mL of a 0.1 mol / L (N / 10) nitric acid aqueous solution. The Na content in the obtained aqueous solution was measured using an ICP-OES analyzer (product name: CIROS120 E0P, manufactured by Rigaku Corporation), and the Na content in the entire silica particles was determined by dividing by the Si content.

[0093] [Measurement of particle size by dynamic light scattering method (DLS)] The particle size by the dynamic light scattering method was measured using a dynamic light scattering particle size measuring device (manufactured by Spectris, product name: Zetasizer Nano). The Z-average particle size was adopted as the particle size by the dynamic light scattering method.

[0094] [Measurement of Specific Surface Area (C) (S N2 ) by Nitrogen Adsorption Method (BET Method)] The specific surface area (S N2 ) of silica particles in the aqueous dispersion of hollow silica sol by the nitrogen adsorption method was measured as follows: After removing the water-soluble cations in the aqueous dispersion of hollow silica sol with a cation exchange resin (manufactured by Dow Chemical Company, trade name: Amberlite IR-120B), the hollow silica sol was dried at 290 °C to obtain a measurement sample, and this was measured using a specific surface area measuring device for the nitrogen adsorption method, Monosorb (manufactured by Contactrohm Instruments Japan Co., Ltd.).

[0095] [Measurement of Average Primary Particle Size by TEM (Transmission Electron Microscope)] The silica particles in the hollow silica sol were photographed with a transmission electron microscope (manufactured by JEOL Ltd., trade name: JEM-F200), and about 300 arbitrarily selected particles were binarized with an automatic image processing and analysis device (manufactured by Nireco Corporation, trade name: LU ZEX‘ AP). The diameter obtained by converting the projected area into a circle was measured as the average primary particle size (Heywood diameter).

[0096] [TEM-Equivalent Specific Surface Area (D)] Assuming true spherical particles with a true density of 2.2 g / cm 3 , using the average primary particle size obtained in [Measurement of Average Primary Particle Size by TEM (Transmission Electron Microscope)], it was calculated as (TEM-equivalent specific surface area (D) = 2720 / average primary particle size).

[0097] [Measurement of the Amount of Aluminum (A) Bonded to the Surface of Hollow Silica Particles / Leaching Method] The cationic components in the hollow silica sol were removed with an H-type cation exchange resin, and the solvent was removed by heat treatment. The dried product was pulverized in a mortar and further treated at 250 °C for 2 hours. 0.2 g of the obtained powder was put into a polypropylene container (PP sample bottle 50 mL) containing 20 mL of a 0.1 mol / L (N / 10) nitric acid aqueous solution, and shaken vigorously by hand. Next, ultrasonic treatment was performed for 10 minutes with an ultrasonic cleaner (ASU CLEANER ASU-10M manufactured by AS ONE) to thoroughly mix the powder and the nitric acid aqueous solution. It was put into a 50 °C constant temperature bath and held for 17 hours. Then, the internal solution was cooled to room temperature, charged into a centrifugal ultrafiltration filter (Amicon Ultra-15, molecular weight cut-off 10,000), and the amount of aluminum in the filtrate obtained by centrifugation was measured with an ICP emission spectrometer. The amount of aluminum bound to the surface of the hollow silica particles was determined as the ratio of Al2O3 (ppm) to the mass of SiO2 of the hollow silica in terms of Al2O3 (Al2O3(ppm) / SiO2).

[0098] [Measurement / Dissolution method of the amount of aluminum (B) present in the whole hollow silica particles] 0.2 g of the powder obtained by drying the accurately weighed hollow silica sol was treated with 20 mL of a 48 mass% hydrofluoric acid solution to remove the silica component, and the residue was dissolved in 20 mL of a 0.1 mol / L (N / 10) nitric acid aqueous solution. The amount of aluminum in the obtained aqueous solution was measured with an ICP emission spectrometer, and the amount of aluminum present in the whole hollow silica particles was determined as the ratio of Al2O3 (ppm) to the mass of SiO2 of the hollow silica in terms of Al2O3 (Al2O3(ppm) / SiO2).

[0099] [Measurement of the surface charge amount of hollow silica particles] 10 mL of methanol was added with and diluted by hollow silica sol so that the silica concentration became 0.5 mass%, and it was used as a measurement sample. Using a particle charge meter (manufactured by Freytag Turbo Co., Ltd., trade name: PCD-06), a 0.001 mol / L (N / 1000) diallyldimethylammonium chloride solution (manufactured by Freytag Turbo Co., Ltd.) as a cation standard titrant, the titration value until the streaming potential of the measurement sample became zero was measured. The obtained titration value was divided by the silica mass contained in the measurement sample, and the value converted per 1 g of hollow silica particles was defined as the surface charge amount (μeq / g-SiO2).

[0100] [Example 1] (a) Step: 150 g of a water-dispersed hollow silica sol (manufactured by Ningbo Dilato Co., Ltd., trade name: HKT-A20-40D) was charged into a 500 cc eggplant-shaped flask, and while stirring with a magnetic stirrer, an aqueous sodium hydroxide solution was added dropwise so that the sodium content in the water-dispersed hollow silica sol became 384 ppm / SiO2 (that is, the contained Na2O amount was 182.16×10 -6 mol / SiO2 in terms of the molar ratio of Na2O to SiO2). The obtained silica sol had a pH of 10.1, a particle size of 55 nm by the dynamic light scattering method, an average primary particle size of 43 nm by TEM observation, a silica concentration of 20 mass%, a specific surface area (C) of 150 m 2 / g by the BET method, a TEM-converted specific surface area (D) of 63 m 2 / g, a specific surface area ratio (C / D ratio) of 2.4, the amount of aluminum (A) bonded to the particle surface was 0.1 ppm in terms of Al2O3 with respect to the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particles was 0.5 ppm in terms of Al2O3 with respect to the mass of SiO2 of the hollow silica particles, the (A / B ratio) was 0.20, the sodium content in the water-dispersed hollow silica sol was 384 ppm / SiO2, that is, the contained Na2O amount was 182×10 -6 mol / SiO2 in terms of the molar ratio of Na2O to SiO2. (b) Process: Subsequently, 56 g of methanol was added to 150 g of the obtained aqueous dispersion of hollow silica sol, and while feeding methanol using a rotary evaporator under heating and reduced pressure (bath temperature: 120 °C, degree of reduced pressure: 580 Torr), water was distilled off to obtain a methanol dispersion of hollow silica (methanol-dispersed hollow silica sol). When the water content of the methanol-dispersed hollow silica sol reached 2.0 mass% or less, the methanol substitution was terminated, and 150 g of the methanol-dispersed hollow silica sol was obtained. The obtained methanol-dispersed hollow silica sol had a silica concentration of 21 mass%, a water content of 1.3 mass%, a particle diameter by dynamic light scattering method of 66 nm, a pH of 9.0, a specific surface area (C) by BET method of 150 m 2 / g, a TEM-converted specific surface area (D) of 63 m 2 / g, a specific surface area ratio (C / D ratio) of 2.4, the amount of aluminum (A) bonded to the particle surface was 0.1 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particles was 0.5 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, (A / B ratio) was 0.20, the sodium content in the methanol-dispersed hollow silica sol was 384 ppm / SiO2, that is, the contained Na2O amount was 182×10 -6 mol / SiO2 as the molar ratio of Na2O to SiO2. The obtained methanol-dispersed hollow silica sol was sealed in a 30 cc glass bottle and further stored in an explosion-proof constant temperature bath (manufactured by Espec Corporation, product name: Constant Temperature Bath with Safety Door) maintained at 50 °C for 48 hours. By comparing the particle diameters by dynamic light scattering before and after storage at 50 °C, the stability of the methanol-dispersed hollow silica sol was confirmed. When the particle diameter by dynamic light scattering method before charging at 50 °C was within a range of 2.0 times or less of the particle diameter by dynamic light scattering method after storage at 50 °C for 48 hours compared to before storage, it was evaluated as "stable", and when it exceeded 2.0 times, it was evaluated as "unstable". The stability of the methanol-dispersed hollow silica sol obtained in Example 1 is shown in Table 1.

[0101] 〔Example 2〕 (a) Process: 150 g of a water-dispersed hollow silica sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40D) was charged into a 500 cc eggplant-shaped flask, and while stirring with a magnetic stirrer, an aqueous sodium hydroxide solution was dropped in so that the sodium content in the water-dispersed hollow silica sol was 384 ppm / SiO2 (i.e., the content of Na2O was 182.16×10 -6 mol / SiO2 in terms of the molar ratio of Na2O to SiO2). Further, while stirring with a magnetic stirrer, 0.16 g of diethanolamine was dropped in. The obtained silica sol had a pH of 10.2, a particle size of 55 nm by the dynamic light scattering method, an average primary particle size of 43 nm by TEM observation, a silica concentration of 20 mass%, a specific surface area (C) of 150 m 2 / g by the BET method, a TEM-converted specific surface area (D) of 63 m 2 / g, a specific surface area ratio (C / D ratio) of 2.4, the amount of aluminum (A) bound to the particle surface was 0.1 ppm in terms of Al2O3 with respect to the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particles was 0.5 ppm in terms of Al2O3 with respect to the mass of SiO2 of the hollow silica particles, the (A / B ratio) was 0.20, the sodium content in the water-dispersed hollow silica sol was 384 ppm / SiO2, i.e., the content of Na2O was 182×10 -6 mol / SiO2 in terms of the molar ratio of Na2O to SiO2. (b) Process: Then, 56 g of methanol was added to 150 g of the obtained water-dispersed hollow silica sol, and while feeding methanol under heating and reduced pressure (bath temperature: 120 °C, reduced pressure: 580 Torr) using a rotary evaporator, water was distilled off to obtain a methanol-dispersed liquid of hollow silica (methanol-dispersed hollow silica sol). When the water content of the methanol-dispersed hollow silica sol became 2.0 mass% or less, the methanol substitution was terminated, and 150 g of the methanol-dispersed hollow silica sol was obtained. The obtained methanol-dispersed hollow silica sol had a silica concentration of 21 mass%, a water content of 0.4 mass%, a particle size of 66 nm by the dynamic light scattering method, a specific surface area (C) of 150 m 2 / g by the BET method, a TEM-converted specific surface area (D) of 63 m 2 / g, a specific surface area ratio (C / D ratio) of 2.4, and bound to the particle surface The amount of aluminum (A) was 0.1 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, the ratio of the amount of aluminum (B) present in the whole particles in terms of Al2O3 to the mass of SiO2 of the hollow silica particles was 0.5 ppm, the (A / B ratio) was 0.20, and the amount of sodium contained in the methanol-dispersed hollow silica sol was 384 ppm / SiO2, that is, the amount of contained Na2O was 182×10 -6 mol / SiO2. A stability test similar to that of Example 1 was carried out and shown in Table 1.

[0102] [Example 3] (a) Step: 150 g of an aqueous dispersion of hollow silica sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40D) was charged into a 500 cc eggplant-shaped flask, and while stirring with a magnetic stirrer, an aqueous sodium hydroxide solution was added dropwise so that the amount of sodium contained in the aqueous dispersion of hollow silica sol was 384 ppm / SiO2 (that is, the amount of contained Na2O was 182.16×10 -6 mol / SiO2). Further, while stirring with a magnetic stirrer, 0.16 g of diethanolamine was added dropwise. The obtained silica sol had a pH of 10.2, a particle size of 55 nm by the dynamic light scattering method, an average primary particle size of 43 nm by TEM observation, a silica concentration of 20% by mass, a specific surface area (C) of 150 m 2 / g by the BET method, a TEM-converted specific surface area (D) of 63 m 2 / g, a specific surface area ratio (C / D ratio) of 2.4, the amount of aluminum (A) bonded to the particle surface was 0.1 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, the ratio of the amount of aluminum (B) present in the whole particles in terms of Al2O3 to the mass of SiO2 of the hollow silica particles was 0.5 ppm, the (A / B ratio) was 0.20, and the amount of sodium contained in the aqueous dispersion of hollow silica sol was 384 ppm / SiO2, that is, the amount of contained Na2O was 182×10 -6 mol / SiO2. (b) Process: Subsequently, 56 g of methanol was added to 150 g of the obtained aqueous dispersion of hollow silica sol, and while feeding methanol using a rotary evaporator under heating and reduced pressure (bath temperature: 120 °C, degree of reduced pressure: 580 Torr), water was distilled off to obtain a methanol dispersion of hollow silica (methanol-dispersed hollow silica sol). When the water content of the methanol-dispersed hollow silica sol reached 2.0 mass% or less, the methanol substitution was terminated, and 150 g of the methanol-dispersed hollow silica sol was obtained. 30 g of the methanol-dispersed hollow silica sol was charged into a 50 cc eggplant-shaped flask, and 0.33 g of pure water was added while stirring with a magnetic stirrer. The obtained methanol-dispersed hollow silica sol had a silica concentration of 21 mass%, a water content of 1.5 mass%, a particle diameter by dynamic light scattering method of 66 nm, a specific surface area (C) of 150 m 2 / g, a TEM-converted specific surface area (D) of 63 m 2 / g, a specific surface area ratio (C / D ratio) of 2.4, the amount of aluminum (A) bonded to the particle surface was 0.1 ppm in terms of Al2O3 relative to the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particles was 0.5 ppm in terms of Al2O3 relative to the mass of SiO2 of the hollow silica particles, (A / B ratio) was 0.20, the sodium content in the methanol-dispersed hollow silica sol was 384 ppm / SiO2, that is, the contained Na2O amount was 182×10 -6 mol / SiO2 in terms of the molar ratio of Na2O to SiO2. The same stability test as in Example 1 was conducted and shown in Table 1.

[0103] 〔Example 4〕 (a) Process: 150 g of an aqueous dispersion of hollow silica sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40D) was charged into a 500 cc eggplant-shaped flask, and while stirring with a magnetic stirrer, the sodium content in the aqueous dispersion of hollow silica sol was 192 ppm / SiO2 (that is, the contained Na2O amount was 91.08×10 -6An aqueous sodium hydroxide solution was added dropwise so that it became (mol / SiO₂). Further, while stirring with a magnetic stirrer, 0.16 g of diethanolamine was added dropwise. The obtained silica sol had a pH of 9.8, a particle size of 55 nm by the dynamic light scattering method, and an average primary particle size: 43 nm, silica concentration 20 mass%, specific surface area (C) 150 m 2 / g by the BET method, TEM-converted specific surface area (D) 63 m 2 / g, specific surface area ratio (C / D ratio) of 2.4, the amount of aluminum (A) bound to the particle surface was 0.1 ppm in terms of Al₂O₃ based on the mass of SiO₂ of the hollow silica particles, and the amount of aluminum (B) present in the whole particles was 0.5 ppm in terms of Al₂O₃ based on the mass of SiO₂ of the hollow silica particles. The (A / B ratio) was 0.20, the amount of sodium contained in the aqueous dispersion of hollow silica sol was 192 ppm / SiO₂, that is, the amount of contained Na₂O was 91×10 -6 mol / SiO₂. (b) Step: Thereafter, 56 g of methanol was added to 150 g of the obtained aqueous dispersion of hollow silica sol, and while feeding methanol under heating and reduced pressure (bath temperature: 120 °C, degree of reduced pressure: 580 Torr) using a rotary evaporator, water was distilled off to obtain a methanol dispersion of hollow silica (methanol-dispersed hollow silica sol). When the water content of the methanol-dispersed hollow silica sol became 2.0 mass% or less, the methanol substitution was terminated, and 150 g of the methanol-dispersed hollow silica sol was obtained. The obtained methanol-dispersed hollow silica sol had a silica concentration of 21 mass%, a water content of 0.6 mass%, a particle size of 66 nm by the dynamic light scattering method, and a specific surface area (C) 150 m 2 / g by the BET method, TEM-converted specific surface area (D) 63 m 2 / g, the specific surface area ratio (C / D ratio) is 2.4, the amount of aluminum (A) bound to the particle surface is 0.1 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particle is 0.5 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, (A / B ratio) is 0.20, the amount of sodium contained in the methanol-dispersed hollow silica sol is 192 ppm / SiO2, that is, the amount of contained Na2O is 182×10 -6 mol / SiO2. The same stability test as in Example 1 was carried out and shown in Table 1.

[0104] [Example 5] (a) Step: 150 g of an aqueous dispersion of hollow silica sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40D) was charged into a 500 cc eggplant-shaped flask, and while stirring with a magnetic stirrer, an aqueous sodium hydroxide solution was added dropwise so that the amount of sodium contained in the aqueous dispersion of hollow silica sol was 192 ppm / SiO2 (that is, the amount of contained Na2O was 91.08×10 -6 mol / SiO2 in terms of the molar ratio of Na2O to SiO2). Further, while stirring with a magnetic stirrer, 0.16 g of diethanolamine was added dropwise. The obtained silica sol had a pH of 9.8, a particle size of 55 nm by the dynamic light scattering method, an average primary particle size of 43 nm by TEM observation, a silica concentration of 20% by mass, a specific surface area (C) of 150 m 2 / g, a TEM-converted specific surface area (D) of 63 m 2 / g, the specific surface area ratio (C / D ratio) is 2.4, the amount of aluminum (A) bound to the particle surface is 0.1 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particle is 0.5 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, (A / B ratio) is 0.20, the amount of sodium contained in the aqueous dispersion of hollow silica sol is 192 ppm / SiO2, that is, the amount of contained Na2O is 91×10 -6 mol / SiO2. (b) Process: Subsequently, 56 g of methanol was added to 150 g of the obtained aqueous dispersion of hollow silica sol, and while feeding methanol using a rotary evaporator under heating and reduced pressure (bath temperature: 120 °C, degree of reduced pressure: 580 Torr), water was distilled off to obtain a methanol dispersion of hollow silica (methanol-dispersed hollow silica sol). When the water content of the methanol-dispersed hollow silica sol reached 2.0 mass% or less, the methanol substitution was terminated, and 150 g of the methanol-dispersed hollow silica sol was obtained. 30 g of the obtained methanol-dispersed hollow silica sol was charged into a 50 cc eggplant-shaped flask, and 0.27 g of pure water was added while stirring with a magnetic stirrer. The obtained methanol-dispersed hollow silica sol had a silica concentration of 21 mass%, a water content of 1.5 mass%, a particle size of 66 nm by the dynamic light scattering method, a specific surface area (C) of 150 m 2 / g by the BET method, a TEM-converted specific surface area (D) of 63 m 2 / g, a specific surface area ratio (C / D ratio) of 2.4, the amount of aluminum (A) bound to the particle surface was 0.1 ppm in terms of Al2O3 relative to the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particles was 0.5 ppm in terms of Al2O3 relative to the mass of SiO2 of the hollow silica particles, the (A / B ratio) was 0.20, the sodium content in the methanol-dispersed hollow silica sol was 192 ppm / SiO2, that is, the contained Na2O amount was 182 × 10 -6 mol / SiO2 as the molar ratio of Na2O to SiO2. The same stability test as in Example 1 was conducted and shown in Table 1.

[0105] 〔Example 6〕 (a) Process: 150 g of an aqueous dispersion of hollow silica sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40D) was charged into a 500 cc eggplant-shaped flask, and 0.16 g of diethanolamine was added dropwise while stirring with a magnetic stirrer. The obtained silica sol had a pH of 9.5, a particle size of 55 nm by the dynamic light scattering method, an average primary particle size of 43 nm by TEM observation, a silica concentration of 20 mass%, a specific surface area (C) of 150 m 2 / g by the BET method, a TEM-converted specific surface area (D) of 63 m 2 / g, the specific surface area ratio (C / D ratio) is 2.4, the amount of aluminum (A) bonded to the particle surface is 0.1 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particles is 0.5 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, (A / B ratio) is 0.20, the sodium content in the aqueous dispersion of hollow silica sol is 14 ppm / SiO2, that is, the content of Na2O is 6.64×10 -6 mol / SiO2. (b) Step: Then, 56 g of methanol was added to 150 g of the obtained aqueous dispersion of hollow silica sol, and while feeding methanol under heating and reduced pressure (bath temperature: 120 °C, degree of reduced pressure: 580 Torr) using a rotary evaporator, water was distilled off to obtain a methanol dispersion of hollow silica (methanol-dispersed hollow silica sol). When the water content of the methanol-dispersed hollow silica sol became 2.0 mass% or less, the methanol substitution was terminated, and 150 g of the methanol-dispersed hollow silica sol was obtained. (c) Step: Then, while stirring 100 g of the obtained methanol-dispersed hollow silica sol with a magnetic stirrer, an aqueous sodium hydroxide solution diluted with methanol was added dropwise so that the sodium content in the aqueous dispersion of hollow silica sol was 384 ppm / SiO2, that is, the content of Na2O was 182.16×10 -6 mol / SiO2). The obtained methanol-dispersed hollow silica sol had a silica concentration of 20 mass%, a water content of 1.8 mass%, a particle diameter of 78 nm by the dynamic light scattering method, a specific surface area (C) of 150 m 2 / g by the BET method, a TEM-converted specific surface area (D) of 63 m 2 / g, the specific surface area ratio (C / D ratio) is 2.4, the amount of aluminum (A) bonded to the particle surface is 0.1 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, the amount of aluminum (B) present in the whole particles is 0.5 ppm in terms of Al2O3 based on the mass of SiO2 of the hollow silica particles, (A / B ratio) is 0.20, the sodium content in the methanol-dispersed hollow silica sol is 384 ppm / SiO2, that is, the content of Na2O is 182×10-6 It was mol / SiO2. A stability test similar to that of Example 1 was conducted and shown in Table 1.

[0106] [Comparative Example 1] (a) Step: 150 g of an aqueous dispersion of hollow silica sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40D) was charged into a 500 cc eggplant-shaped flask, and while stirring with a magnetic stirrer, 0.16 g of diethanolamine was added dropwise. (b) Step: Then, 56 g of methanol was added to 150 g of the obtained aqueous dispersion of hollow silica sol, and while feeding methanol under heating and reduced pressure (bath temperature: 120 °C, degree of reduced pressure: 580 Torr) using a rotary evaporator, water was distilled off to obtain a methanol dispersion of hollow silica (methanol-dispersed hollow silica sol). When the water content of the methanol-dispersed hollow silica sol became 2.0 mass% or less, the methanol substitution was terminated, and 150 g of the methanol-dispersed hollow silica sol was obtained. The obtained methanol-dispersed hollow silica sol had a silica concentration of 20 mass%, a water content of 0.8 mass%, and a particle diameter of 123 nm by the dynamic light scattering method. The content of Na2O was 6.64×10 mol / SiO2) -6 mol / SiO2) A stability test similar to that of Example 1 was conducted and shown in Table 1. [Table 1] Table 1 ―――――――――――――――――――――――――――――――――――――― DLS particle diameter (nm) DLS particle diameter (nm) DLS particle diameter (nm) Result (Initial) (Before stability test) (After stability test) Example 1 66 66 67 Stable Example 2 66 66 66 Stable Example 3 66 66 67 Stable Example 4 66 66 67 Stable Example 5 66 66 67 Stable Example 6 78 78 73 Stable Comparative Example 1 105 105 235 Unstable ――――――――――――――――――――――――――――――――――――――

[0107] The average particle diameter by the dynamic light scattering method is 20 to 150 nm, and the molar ratio of monovalent alkali metal ions to SiO2 of the hollow silica particles converted to M2O (where M represents a monovalent alkali metal atom) is 7.12×10 -6 ~285×10 -6 For the sols of Examples 1 to 6, which contain the ratio, it was confirmed that the value of the particle diameter by the dynamic light scattering method after storage at 50°C for 48 hours was within 2.0 times the value before storage, indicating high stability. On the other hand, even when the average particle diameter by the dynamic light scattering method is 20 to 150 nm, the molar ratio of monovalent alkali metal ions to SiO2 of the hollow silica particles converted to M2O (where M represents a monovalent alkali metal atom) is 7.12×10 -6 For Comparative Example 1, which is a sol containing less than the ratio, it was confirmed that the value of the particle diameter by the dynamic light scattering method after storage at 50°C for 48 hours exceeded 2.0 times the value before storage, indicating low stability.

[0108] Furthermore, as shown in Table 1, even for a sol with an average particle diameter by the dynamic light scattering method of 20 to 150 nm and a molar ratio of monovalent alkali metal ions to SiO2 of the hollow silica particles converted to M2O (where M represents a monovalent alkali metal atom) of less than 7.12×10 -6 For Example 6, which is a sol obtained by adjusting with the addition of monovalent alkali metal ions after methanol substitution and containing the ratio of monovalent alkali metal ions to SiO2 of the hollow silica particles converted to M2O (where M represents a monovalent alkali metal atom) of 7.12×10 -6 ~285×10 -6 It was confirmed that the value of the particle diameter by the dynamic light scattering method after storage at 50°C for 48 hours was within 2.0 times the value before storage, indicating high stability.

Industrial Applicability

[0109] The present invention relates to an aqueous sol and an organic solvent sol containing highly stable hollow silica particles, and further to a method for improving the stability of the sol with reduced storage stability and a production method thereof.

Claims

1. comprising hollow silica particles having a space inside the outer shell and monovalent alkali metal ions, The number of moles of the monovalent alkali metal ion converted to M ２ O (where M represents a monovalent alkali metal atom) is 6.64×10 ２ with respect to the number of moles of SiO －６ in the hollow silica particles, and the hollow silica sol contains it in a proportion exceeding this value.

2. The hollow silica sol according to claim 1, wherein the monovalent alkali metal ion is a sodium ion.

3. The hollow silica sol according to claim 1, having an average particle diameter of 20 to 150 nm by the dynamic light scattering method.

4. Furthermore, it contains an amine, and the amine is 0.001 to 10% by mass based on SiO of the hollow silica particles. ２ The hollow silica sol according to claim 1.

5. The hollow silica sol according to claim 4, wherein the amine is at least one amine selected from the group consisting of primary amines, secondary amines, and tertiary amines having 1 to 10 carbon atoms.

6. The hollow silica sol according to claim 4, wherein the amine is a water-soluble amine having a water solubility of 80 g / L or more.

7. further comprising aluminum atoms in which the hollow silica particles have formed aluminosilicate sites, the aluminum atoms being bonded to the surface of the hollow silica particles, The mass of the aluminum atoms is in the range of a ratio (A) of 100 to 20,000 ppm in terms of Al ２ to the mass of SiO ２ in the hollow silica particles, and ３ is in the range of 100 to 20,000 ppm in terms of Al the mass of the aluminum atoms being a value measured by a leaching method, The hollow silica sol according to claim 1.

8. The leaching method measurement for leaching aluminum atoms from a compound containing aluminum atoms bonded to the surface of the hollow silica particles uses an aqueous solution of at least one mineral acid selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid. The hollow silica sol according to claim 7.

9. The mass of aluminum atoms present in the entire hollow silica particles is Al ２ O ３ in terms of conversion, and is represented by a ratio (B) of 120 to 50,000 ppm with respect to the mass of SiO ２ of the hollow silica particles. The mass of the aluminum atoms is a value measured by dissolving the hollow silica particles in an aqueous hydrofluoric acid solution by a dissolution method, The hollow silica sol according to claim 7, wherein the ratio (A) / the ratio (B) is 0.002 to 1.

0.

10. The hollow silica sol according to claim 1, comprising the above hollow silica particles, wherein the ratio of [specific surface area (C) of silica particles by the BET method (nitrogen gas adsorption method)] / [specific surface area (D) of silica particles converted from a transmission electron microscope] is 1.40 to 5.

00.

11. The surface charge amount of the hollow silica particles is 5 to 250 μeq / g per gram in terms of SiO ２ The hollow silica sol according to claim 1, comprising hollow silica particles having a surface charge amount of 5 to 250 μeq / g per gram in terms of SiO

12. The above hollow silica particles further have the following formulas (1) and (2): 【Chemical 1】 (In formula (1), R １ is a group bonded to a silicon atom, and independently of one another, 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 a silicon atom by an Si—C bond, or represents a combination of these groups, R ２ is a group or atom bonded to a silicon atom, and independently of one another, represents an alkoxy group having 1 or more carbon atoms, an acyloxy group, a hydroxy group, or a halogen atom, or represents a combination of these groups, a represents an integer of 1 to 3, In formula (2), R ３ is a group bonded to a silicon atom, independently representing 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 through an Si-C bond, or represents a combination of these groups, R ４ is a group or atom bonded to a silicon atom, and independently of one another represents an alkoxy group having 1 or more carbon atoms, an acyloxy group, a hydroxy group, or a halogen atom, or represents a combination of these groups, Y is a group or atom bonded to a silicon atom, and represents an alkylene group, an NH group, or an oxygen atom, b represents an integer of 1 to 3, and c represents an integer of 0 or 1.) The hollow silica sol according to claim 1, comprising hollow silica particles coated with at least one silane compound selected from the group consisting of compounds represented by

13. The hollow silica sol according to claim 1, wherein the dispersion medium of the hollow silica sol is water, an alcohol having 1 to 10 carbon atoms, a ketone, an ether, an amide, a urea, or an ester.

14. A film-forming composition comprising hollow silica particles derived from the hollow silica sol according to any one of claims 1 to 13 and an organic resin or polysiloxane.

15. A film having a visible light transmittance of 80% or more obtained from the film-forming composition according to claim 14.

16. The following steps (I) to (II): Step (I): A step of preparing a hollow silica sol containing a dispersion medium (II) Step: To the hollow silica sol in the (I) step, monovalent alkali metal ions are added and adjusted so that the molar ratio converted to M ２ 2O (where M represents a monovalent alkali metal atom) with respect to SiO ２ 2 of the hollow silica particles exceeds 6.64×10 －６ . ２ For 2, monovalent alkali metal ions are added in a ratio such that ２ the molar ratio converted to M ２ 2O (where M represents a monovalent alkali metal atom) is more than 6.64×10 －６ . －６ This is the step of adding and adjusting monovalent alkali metal ions to achieve a ratio exceeding 6.64×10 －６ . The method for producing a hollow silica sol according to any one of claims 1 to 13, comprising

17. The method for producing a hollow silica sol according to claim 16, wherein the monovalent alkali metal ion is a sodium ion in the step (II).

18. The method for producing a hollow silica sol according to claim 17, wherein the adjustment of the sodium ion content in the step (II) is to contact the hollow silica sol obtained in the step (I) with a cation exchange resin or to add a sodium source.

19. The method for producing a hollow silica sol according to claim 17, wherein the addition of the sodium source in the step (II) is the addition of sodium hydroxide.

20. The method for producing a hollow silica sol according to claim 16, wherein the dispersion media in the steps (I) and (II) are water, an alcohol having 1 to 10 carbon atoms, a ketone, an ether, an amide, a urea, or an ester.

21. The method for producing a hollow silica sol according to claim 16, wherein at least one step selected from the following (i) to (iv) is added in the step (I), the step (II), or both steps. (i): Adding an amine to the hollow silica sol (ii): Adding sodium aluminate as an aluminum source and heating to form an aluminosilicate site on the hollow silica particles (iii): Replacing the dispersion medium with another dispersion medium (iv): Further coating the hollow silica particles with at least one silane compound selected from the group consisting of formula (1) and formula (2).

22. A method for stabilizing a hollow silica sol containing hollow silica particles having a space inside the outer shell, comprising To the hollow silica sol in which the value of the average particle diameter by the dynamic light scattering method has increased compared to that during production, The number of moles of the above-mentioned monovalent alkali metal ions converted to M ２ O (where M represents a monovalent alkali metal atom) is 6.64×10 ２ with respect to the number of moles of SiO －６ in the hollow silica particles in the hollow silica sol, and the monovalent alkali metal ions are added so as to have a molar ratio exceeding A method for stabilizing a hollow silica sol according to claim 1, characterized in that the average particle diameter by the dynamic light scattering method, which has increased, is decreased.

23. The method for stabilizing a hollow silica sol according to claim 22, wherein the monovalent alkali metal ion is a sodium ion.

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