CN118488926A

CN118488926A - Hollow silica particles containing aluminum atoms and method for producing same

Info

Publication number: CN118488926A
Application number: CN202380015086.2A
Authority: CN
Inventors: 西村透; 下吉真实; 飞田将大; 山田修平
Original assignee: Nissan Chemical Corp
Current assignee: Nissan Chemical Corp
Priority date: 2022-11-04
Filing date: 2023-11-02
Publication date: 2024-08-13

Abstract

The present invention provides hollow silica particles in which aluminum atoms are bonded to the surfaces of hollow silica particles in a specific ratio by Al ₂O₃ conversion, and a hollow silica sol for mixing the hollow silica particles with an organic solvent and a resin with good compatibility. The hollow silica particles contain aluminum atoms forming aluminosilicate sites, and the aluminum atoms are bonded to the surfaces of the hollow silica particles in a ratio (A) of 100 to 20000ppm/SiO ₂ to 1g SiO ₂ in terms of Al ₂O₃ converter in the measurement by the leaching method. The leaching method is a method in which the hollow silica particles are leached with an aqueous solution of at least 1 inorganic acid selected from sulfuric acid, nitric acid and hydrochloric acid, and the ratio (a) of 1g SiO ₂ to the hollow silica particles is calculated in terms of Al ₂O₃ of a compound containing aluminum atoms bonded to the surfaces of the hollow silica particles.

Description

Hollow silica particles containing aluminum atoms and method for producing same

Technical Field

The present invention relates to a sol in which hollow silica particles containing aluminum atoms are dispersed in water or an organic solvent, a method for producing the same, and a composition for forming a coating film.

Background

The hollow silica particles having a space inside the shell and having a silica shell have characteristics such as a low refractive index, a low thermal conductivity (heat insulating property), and electrical insulation property, according to their characteristics.

The hollow silica particles are composed of a core corresponding to the cavity portion and a shell forming the outer side of the core, and an aqueous dispersion of the hollow silica particles is obtained by a method of forming a silica layer on the outer side of the core in an aqueous medium and then removing the core.

For example, a method for producing an acidic silica sol, which comprises adding an alkali aluminate aqueous solution containing aluminum atoms in a molar ratio of 0.0006 to 0.004 based on Al ₂O₃/SiO₂ to a solid silica particle dispersion, heating the resultant silica sol at 80 to 250 ℃, and cation-exchanging the silica sol, is disclosed (see patent document 1).

Furthermore, it is disclosed that: a method for obtaining aqueous solid silica sol, wherein the aqueous solid silica sol is obtained by heating active silicic acid obtained by cation exchange of aqueous alkali silicate solution containing aluminum atoms at 80-300 ℃; or a method for obtaining aqueous solid silica sol, wherein alkali aluminate is added into the aqueous solid silica sol, and the aqueous solid silica sol is obtained by heating at 80-300 ℃; in the silica sol, the solid silica particles obtained by these methods contain aluminum atoms forming aluminosilicate sites on the surface thereof, and in the measurement by the leaching method, the silica particles are dispersed in a nitrogen-containing solvent, and the aluminum atoms are bonded to the surface of the silica particles in a ratio of 800 to 20000ppm/SiO ₂ in terms of Al ₂O₃ (see patent document 2).

Further, a method for producing a hollow silica sol is disclosed in which core-shell particles in which a silane compound and an aluminum precursor are reacted in a molar ratio of Si/Al ranging from 7 to 15 in a template core composed of micelles or inverse micelles of an organic polymer are produced, and the core-shell particles are reacted with an alkaline aqueous solution or an acidic aqueous solution to form pores and remove cores from a shell (housing), and then a hydrothermal reaction is performed at 160 to 200 ℃ to produce a hollow silica sol (see patent document 3).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 6-199515

Patent document 2: international publication No. 2022/097694

Patent document 3: korean patent No. 10-1659709

Disclosure of Invention

Problems to be solved by the invention

Aluminosilicate sites generated by the reaction of aluminate ions with silanol groups on the surface of silica particles are known to give negative charge to silica particles in the silica sol. The aluminosilicate sites increase the stability of the silica particles in the dispersion medium by increasing the negative zeta potential. In particular, the compatibility of silica particles with organic solvents and resins having charges is improved.

In addition, the alumina compound is incorporated into the silica particles by the particle growth by containing the alumina compound in the acidic silica liquid, and the alkali metal present in the silica particles is trapped in the silica particles, thereby obtaining a stable silica sol. The alkali metal encapsulated in the silica particles is released to the outside of the system with the lapse of time, and causes instability. Further, since aluminosilicate is formed even inside silica particles which are not required for stabilization, the amount of aluminum present in the aluminosilicate of the silica particles becomes large, and alkali metal bonded to the aluminosilicate becomes large, and flows out from the silica particles to the outside over time.

In the solid silica particles having no cavity in the silica particles, after the silica particles are formed, an aluminosilicate site can be formed near the surface by impregnating the aluminum compound from the surface, and even if the aluminum compound is impregnated up to a portion close to the center of the silica particles, sodium is maintained in an internal state.

On the other hand, hollow silica particles having a cavity in the interior of the shell are impregnated with an aluminum compound from the outside so that the aluminum compound permeates into the shell, and an alkali metal is also present in which the aluminum compound impregnated on the outside of the shell and the aluminum compound impregnated up to the inside of the shell form aluminosilicate sites, respectively, to be bonded to them. The alkali metal present at the aluminosilicate sites present on the outer side of the shell can be removed at the time of production, but the alkali metal present at the aluminosilicate sites present on the inner side of the shell is difficult to remove at the time of production, and there is a possibility that the alkali metal flows out through the pores of the shell with time.

Means for solving the problems

As a result of intensive studies in view of the above-described circumstances, the present inventors have found that hollow silica particles having high dispersion stability in a medium and free from concerns such as outflow of alkali metal can be obtained by measuring aluminum atoms existing outside the shell of the hollow silica particles and being able to be measured by a leaching method.

In the present invention, from the 1 st point of view, the hollow silica particles having a space in the shell, the hollow silica particles containing aluminum atoms forming aluminosilicate sites, the aluminum atoms being bonded to the surfaces of the hollow silica particles in a ratio (A) of 100 to 20000ppm/SiO ₂ to 1g of SiO ₂ in terms of Al ₂O₃ conversion in the measurement by the leaching method,

In the aspect 2, the hollow silica particles according to the aspect 1 are obtained by leaching hollow silica particles with an aqueous solution of at least 1 inorganic acid selected from sulfuric acid, nitric acid and hydrochloric acid, wherein the leaching method is a method of calculating a ratio (A) of 1g SiO ₂ to hollow silica particles in terms of Al ₂O₃ of a compound containing aluminum atoms bonded to surfaces of hollow silica particles,

In the hollow silica particles according to the aspect 3, in the measurement by the dissolution method using an aqueous hydrofluoric acid solution, aluminum atoms present in the entire hollow silica particles are bonded in a ratio (B) of 120 to 50000ppm/SiO ₂ to 1g SiO ₂ by Al ₂O₃ conversion, the value obtained by dividing the ratio (A) by the ratio (B) is 0.001 to 1.0,

In view 4, the hollow silica particles according to any one of view 1 to 3, wherein the ratio of [ the specific surface area (C) of the hollow silica particles measured by the BET method (nitrogen adsorption method) ]/[ the specific surface area (D) of the hollow silica particles calculated by a transmission electron microscope ],

In view 5, the hollow silica particles according to any one of the aspects 1 to 4, wherein the hollow silica particles have a surface charge amount of 5 to 250. Mu. Eq/g in terms of SiO ₂ per 1g,

As the 6 th aspect, the hollow silica particles according to any one of the 1 st to 5 th aspects, the hollow silica particles being further coated with at least 1 silane compound selected from the group consisting of the formula (1), the formula (2) and the formula (3).

R ¹ _aSi(R²)_4-a (1)

[ R ³ _bSi(R⁴)_3-b〕₂Y_c (2)

R ⁵ _dSi(R⁶)_4-d (3)

(In the formula (1), R ¹ is each an alkyl group, a haloalkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, a (meth) acryloyl group, a mercapto group, a amino group, a ureido group, or a cyano group and bonded to a silicon atom through a Si-C bond, R ² is each an alkoxy group, an acyloxy group, or a halogen atom, a is an integer of 1 to 3,

In the formula (2) and the formula (3), R ³ and R ⁵ are each an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms and bonded to a silicon atom by a si—c bond, R ⁴ and R ⁶ are each an alkoxy group, an acyloxy group or a halogen atom, Y is 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. )

In the aspect 7, the hollow silica sol according to any one of the aspects 1 to 6 is a sol in which hollow silica particles are dispersed in a dispersion medium, wherein the hollow silica particles have an average particle diameter of 20 to 150nm as measured by a dynamic light scattering method,

In the aspect 8, the hollow silica organic solvent sol according to the aspect 7, wherein the dispersion medium is an alcohol having 1 to 10 carbon atoms, a ketone having 1 to 10 carbon atoms, an ether having 1 to 10 carbon atoms, or an ester having 1 to 10 carbon atoms,

As the 9 th aspect, the hollow silica sol according to the 7 th or 8 th aspect, further comprising an amine,

In a 10 th aspect, the hollow silica sol according to the 9 th aspect, wherein the amine is at least 1 amine selected from the group consisting of primary amines having 1 to 10 carbon atoms, secondary amines having 1 to 10 carbon atoms, and tertiary amines having 1 to 10 carbon atoms,

In the 11 th aspect, the hollow silica sol according to the 9 th or 10 th aspect, wherein the amine is a water-soluble amine having a water solubility of 80g/L or more,

In view of the above, the hollow silica sol according to any one of the view of the invention 9 to the view of the invention 11, wherein the content of the amine is 0.001 to 10% by mass relative to SiO ₂ of the hollow silica particles,

As point 13, a composition for forming a coating film comprising the hollow silica particles according to any one of points 1 to 6 and an organic resin,

The composition for forming a film according to item 14, wherein the hollow silica particles are derived from the hollow silica sol according to any one of items 7 to 12,

In view of the 15 th aspect, there is provided a film obtained from the film-forming composition according to the 13 th or 14 th aspect, having a visible light transmittance of 80% or more,

As the 16 th aspect, the method for producing a hollow silica sol according to any one of the 7 th to 12 th aspects, comprising the following steps (I) and (II):

(I) The working procedure comprises the following steps: a step of preparing a hollow silica aqueous sol;

(II) procedure: adding an aluminum compound to the hollow silica aqueous sol obtained in the step (I) in an amount of 0.0001 to 0.5g per 1g of hollow silica particles in terms of Al ₂O₃, and heating at 40 to 260℃for 0.1 to 48 hours,

In a 17 th aspect, there is provided the method for producing a hollow silica sol according to the 16 th aspect, wherein the hollow silica aqueous sol used in the step (I) is subjected to a step of heating at a heating temperature of less than 100 ℃ in an aqueous medium,

In view of the 18 th aspect, there is provided the method for producing a hollow silica sol according to the 16 th aspect, wherein the hollow silica aqueous sol used in the step (I) is subjected to a step of heating at a heating temperature of 100 to 240 ℃ in an aqueous medium,

In view of the 19 th aspect, the method for producing a hollow silica sol according to any one of the 16 th to 18 th aspects, wherein the aluminum compound used in the step (II) is at least 1 aluminum compound selected from the group consisting of aluminates, aluminum alkoxides, and hydrolysates thereof, and wherein the step (II) uses an aqueous solution containing the same,

As a 20 th aspect, the method for producing a hollow silica sol according to any one of the 16 th to 19 th aspects, wherein the step (II) comprises the steps of: a step (II-i) of adding an amine,

As the 21 st aspect, the method for producing a hollow silica sol according to any one of the 16 th to 19 th aspects, wherein the (II) step comprises the steps of: a step (II-II) in which a neutral salt composed of a combination of at least 1 cation selected from sodium ions, potassium ions and ammonium ions and an inorganic anion or an organic anion is added at a ratio of 0.1 to 10 mass% relative to SiO ₂ of the hollow silica particles,

In a 22 nd aspect, the method for producing a hollow silica sol according to the 21 st aspect, wherein the inorganic anion used in the step (II-II) is a sulfate ion, chloride ion or phosphate ion, the organic anion is a carboxylate ion, a hydroxycarboxylate ion or an amino acid,

As a 23 rd aspect, the method for producing a hollow silica sol according to any one of the 16 th to 22 th aspects, wherein the step (II) comprises the steps of:

a step of adding the aluminum compound or the aluminum compound and at least 1 additive selected from the group consisting of an amine and a neutral salt to the hollow silica aqueous sol and heating the hollow silica aqueous sol; and

A subsequent step of contacting the cation exchange resin with (II-iii), a step of adding an acid (II-iv), or a combination thereof,

As a 24 th aspect, the method for producing a hollow silica sol according to any one of the 16 th to 23 th aspects, further comprising, after the completion of the step (II), the steps of: a step (III) in which the aqueous medium in the hollow silica sol is subjected to solvent substitution with an alcohol having 1 to 10 carbon atoms, a ketone having 1 to 10 carbon atoms, an ether having 1 to 10 carbon atoms, or an ester having 1 to 10 carbon atoms,

As a 25 th aspect, the method for producing a hollow silica sol according to the 24 th aspect, further comprising, after the completion of the step (III), the steps of: a step (IV) of adding and heating at least 1 silane compound selected from the group consisting of the above-mentioned formulas (1), (2) and (3),

In a 26 th aspect, there is provided the method for producing a hollow silica sol according to any one of the 24 th or 25 th aspects, wherein the step (III) and the step (IV) are a step of replacing an aqueous medium of the hollow silica sol with an alcohol having 1 to 10 carbon atoms in the step (III) after completion of the step (II), adding at least 1 silane compound selected from the group consisting of the above-mentioned formulas (1), (2) and (3) in the step (IV), heating the mixture, and then replacing the alcohol solvent with a ketone having 1 to 10 carbon atoms, an ether having 1 to 10 carbon atoms or an ester having 1 to 10 carbon atoms, and

As the 27 th aspect, there is provided a method for adjusting the surface charge of hollow silica particles, wherein the method according to any one of the 16 th to 26 th aspects is used.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the aluminum atom is bonded to the surface of the hollow silica particles in a specific ratio in terms of Al ₂O₃, whereby the hollow silica particles having high dispersion stability in a medium and no concern about outflow of alkali metal or the like can be provided.

Further, according to the present invention, by using the hollow silica particles, a hollow silica sol having good compatibility with an organic solvent can be provided.

Further, according to the present invention, by using the hollow silica particles or the hollow silica sol, a composition for forming a film having good compatibility with a resin can be provided.

Further, according to the present invention, a method for producing a hollow silica sol having excellent compatibility with an organic solvent can be provided.

Detailed Description

The present invention is a hollow silica particle having a space in the interior of a shell, wherein the hollow silica particle contains an aluminum atom forming an aluminosilicate site, and the aluminum atom is bonded to the surface of the hollow silica particle in a ratio (A) of 100 to 20000ppm/SiO ₂ to 1g SiO ₂ in terms of Al ₂O₃ conversion in measurement by a leaching method.

The hollow silica particles have a silica shell, and a space is provided inside the shell. Hollow silica is obtained by a method in which a shell containing silica as a main component is formed on the surface of a portion corresponding to a core called a so-called template (template) in a dispersion medium, and the portion corresponding to the core is removed.

In the present invention, the aluminum atoms can be represented by converting the aluminum atoms into Al ₂O₃ by measuring aluminum present on the surfaces of silica particles by a leaching method using an aqueous solution of at least 1 inorganic acid selected from sulfuric acid, nitric acid and hydrochloric acid. That is, in the measurement of aluminum atoms by the leaching method, the aluminum atoms are present on the surfaces of the hollow silica particles in an amount of 100 to 20000ppm/SiO ₂ or 100 to 15000ppm/SiO ₂, calculated as Al ₂O₃ as calculated with respect to 1g SiO ₂, Or 100 to 10000ppm/SiO ₂, or 100 to 3000ppm/SiO ₂, or 200 to 5000ppm/SiO ₂, or 500 to 5000ppm/SiO ₂, Or a ratio (A) of 800 to 3000ppm/SiO ₂ is bonded to the silica particles. The aluminosilicate sites formed on the surface of the silica particles are important for dispersion in solvents and resins. In the case of producing an acidic hollow silica sol, it is desirable to increase the absolute value of the zeta potential of the hollow silica particles in the acidic region, and in the case where the content of aluminum atoms in terms of Al ₂O₃ in the proportion (a) is less than 100ppm/SiO ₂, the stability of the hollow silica particles tends to be low. When the content of aluminum atoms in the proportion (a) is 3000ppm/SiO ₂ or more in terms of Al ₂O₃, the particle size tends to increase after doping relative to the dynamic light scattering method particle size (DLS particle size) before doping aluminum atoms by using an aluminum compound in the stage of the hollow silica aqueous sol containing aluminum.

The aluminum atoms present as an aluminosilicate on the surface of the silica particles can be leached (eluted) in a structure close to that of an aluminum salt, an aluminum oxide, or an aluminum hydroxide by an aqueous solution of at least 1 inorganic acid selected from sulfuric acid, nitric acid, and hydrochloric acid, and can be represented by Al ₂O₃ in terms of Al by measuring the aluminum atoms from the solution using an ICP emission spectrometry device. In particular, use is made of: a method of leaching (leaching) using an aqueous nitric acid solution. The aqueous nitric acid solution used for leaching may be used in a range of pH 0.5 to 4.0, 0.5 to 3.0, 0.5 to 2.0, or 1.0 to 1.5, and typically an aqueous nitric acid solution having a pH of 1.0 may be used. For example, 100mL of the aqueous nitric acid solution may be added to 1g of silica, and the mixture may be held at a temperature of 20 to 70℃or 40 to 60℃for 10 to 24 hours to dissolve the aluminum compound from the surface of the silica particles, thereby allowing the mixture to be used as an analysis sample.

In the present invention, the silica particle surface may be defined as a region where an aluminum compound can be eluted by the leaching. A silica powder was prepared by grinding a silica gel obtained by evaporating a solvent from a silica sol and further drying the silica gel at 250 ℃,20 mL of an aqueous nitric acid solution having a pH of 1.0 was added to 0.2g of the silica powder and the mixture was sufficiently oscillated, the mixture was kept in a constant temperature bath at 50 ℃ for 17 hours, and after that, the mixture was centrifugally filtered, and the aluminum content in the obtained filtrate was measured by an ICP emission spectrometry device, and the aluminum content converted to Al ₂O₃ was divided by the mass of the silica powder to obtain the amount of aluminum bonded to the surface of silica particles (Al ₂O₃/SiO₂) (ppm).

Even when aluminosilicate is formed on the surface of silica particles, aluminosilicate may be formed not only selectively on the surface but also inside the silica particles according to the production method. The aluminum atoms present in the whole hollow silica particles including the surface and the interior are bonded to the silica particles in a ratio (B) of 120 to 50000ppm/SiO ₂, or 500 to 20000ppm/SiO ₂, or 500 to 10000ppm/SiO ₂, or 1000 to 5000ppm/SiO ₂, or 1000 to 4000ppm/SiO ₂, or 120 to 4000ppm/SiO ₂ in terms of Al ₂O₃ conversion per 1g SiO ₂ of the hollow silica particles.

In the case of producing an acidic hollow silica sol, it is desirable to increase the absolute value of the zeta potential of the hollow silica particles in the acidic region, and in the case where the content of aluminum atoms in terms of Al ₂O₃ in the proportion (B) is less than 120ppm/SiO ₂, the stability of the hollow silica particles tends to be lowered. When the content of aluminum atoms in the proportion (B) is 4000ppm/SiO ₂ or more in terms of Al ₂O₃, the particle size tends to increase after doping relative to the dynamic light scattering method particle size (DLS particle size) before doping aluminum atoms by using an aluminum compound in the stage of the hollow silica aqueous sol containing aluminum.

The ratio of (A)/(B) as the ratio of aluminum present on the surface of the silica particles and the whole silica particles may 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 represented by conversion to Al ₂O₃ by measurement using a dissolution method using an aqueous hydrofluoric acid solution. That is, aluminum atoms present as aluminosilicate in the entire silica particles are measured from an aqueous hydrofluoric acid solution by dissolving the silica particles in the solution using an ICP emission spectrometry device, and the content of aluminum atoms present in the entire silica particles can be expressed in terms of Al ₂O₃.

By forming aluminosilicate sites on the surface of the silica particles in this manner, the negative charge amount per 1g of SiO ₂ of the hollow silica particles present on the surface of the silica particles is measured in the range of 5 to 250. Mu. Eq/g, or 5 to 150. Mu. Eq/g, or 5 to 100. Mu. Eq/g, or 25 to 150. Mu. Eq/g, or 25 to 100. Mu. Eq/g.

The hollow silica particles may be obtained as a hollow silica sol dispersed in a dispersion medium. The hollow silica sol is obtained by dispersing hollow silica particles in a dispersion medium, and the hollow silica particles have an average particle diameter of 20 to 150nm as measured by a dynamic light scattering method.

The hollow silica is obtained by a method of forming a shell containing silica as a main component on the surface of a portion corresponding to the core in a dispersion medium, which is called a template, and removing the portion corresponding to the core, and is in this state a hollow silica aqueous sol.

The hollow silica aqueous sol thus obtained may be subjected to solvent substitution with an alcohol solvent as an organic solvent. The alcohol solvent is preferably an alcohol having 1 to 5 carbon atoms which may have an ether bond, and examples thereof include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like. If necessary, the substrate may be coated with a silane compound and then subjected to solvent substitution with another organic solvent.

In the present invention, examples of the organic solvent include alcohols having 1 to 10 carbon atoms, ketones having 1 to 10 carbon atoms, ethers having 1 to 10 carbon atoms, and esters having 1 to 10 carbon atoms.

The alcohol having 1 to 10 carbon atoms is an aliphatic alcohol, and examples thereof include primary alcohols, secondary alcohols and tertiary alcohols. Further, these alcohols may be used as polyols, and examples thereof include 2-and 3-membered alcohols.

Examples of the 1-primary alcohol include methanol, ethanol, 1-propanol, 1-butanol, and 1-hexanol.

Examples of the 1-membered secondary alcohol include 2-propanol, 2-butanol, cyclohexanol, propylene glycol monomethyl ether, and propylene glycol monoethyl ether.

Examples of the tertiary 1-alcohol include t-butanol.

Examples of the 2-membered alcohol include methane glycol, ethylene glycol, and propylene glycol.

Examples of the 3-membered alcohol include glycerin and the like.

As the ketone having 1 to 10 carbon atoms, an aliphatic ketone can be preferably used. Examples thereof include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and methyl cyclopentanone.

As the ether having 1 to 10 carbon atoms, an aliphatic ether can be preferably used. Examples thereof include dimethyl ether, ethyl methyl ether, diethyl ether, tetrahydrofuran, and 1, 4-diAn alkane, and the like.

As the ester having 1 to 10 carbon atoms, an aliphatic ester can be preferably used. Examples thereof include methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl acrylate, ethyl acrylate, propyl acrylate, dimethyl maleate, diethyl maleate, dipropyl maleate, dimethyl adipate, diethyl adipate, dipropyl adipate, and the like.

In the hollow silica aqueous sol and the hollow silica organic solvent sol as the raw materials, the hollow silica particles may have an average particle diameter in the range of 20 to 150nm, or 30 to 150nm, or 40 to 150nm, or 50 to 120nm, or 50 to 100nm as measured by a dynamic light scattering method (DLS method).

The hollow silica particles may have an average primary particle diameter in the range of 20 to 150nm, 30 to 150nm, 40 to 150nm, 50 to 120nm, or 50 to 100nm, as observed by a transmission electron microscope.

The specific surface area (C) of the hollow silica particles measured by the BET method (nitrogen adsorption method) may be set to 18 to 200m ²/g, or 50 to 160m ²/g, or 60 to 160m ²/g, or 70 to 160m ²/g, or 80 to 150m ²/g.

The specific surface area (D) of the hollow silica particles converted by the transmission electron microscope may be set to 18 to 136m ²/g, or 18 to 90m ²/g, or 18 to 68m ²/g, or 18 to 54m ²/g, or 18 to 27m ²/g, or 18 to 23m ²/g.

Further, the ratio of [ the specific surface area (C) of the hollow silica particles measured by the BET method (nitrogen adsorption method) ]/[ the specific surface area (D) of the hollow silica particles converted by a transmission electron microscope ] may be set to a 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, the silica particles are solid silica particles having no space inside the shell of the silica particles, and when the value of (C)/(D) exceeds 1.0, the silica particles are hollow silica particles having a space inside the shell of the silica particles.

The thickness of the shell of the hollow silica particles as observed by a transmission electron microscope may be in the range of 3.0 to 15.0nm, or 4.0 to 12.0nm, or 5.0 to 10.0 nm.

The refractive index of the hollow silica particles may be in the range of 1.20 to 1.45, or 1.20 to 1.40, or 1.25 to 1.40.

The concentration of SiO ₂ particles in the hollow silica sol is 1 to 50 mass%, or 5 to 40 mass%, and typically 10 to 30 mass% can be used.

The pH of the sol can be adjusted from acidic to basic. The adjustment to acidity is performed by adding an inorganic acid or an organic acid. The adjustment of the basicity is performed by adding an inorganic base or an organic base, and as the organic base, an amine may be added for the purpose of adjusting the pH and the amount of surface charge. The pH may be set to a pH of 1 to less than 7 on the acidic side and may be set to a pH of 7 to 13 on the alkaline side.

The pH of the hollow silica aqueous sol may be set to a range of, for example, 2.0 to 6.0 or 2.0 to 4.5 before the addition of the amine, and the pH may be adjusted to a range of, for example, 3.0 to 10.0 or 3.0 to 9.0 by the addition of the amine.

In the case of an organic solvent sol, the above pH is a value obtained by mixing an organic solvent sol with pure water of the same mass at 1:1, the organic solvent can be measured when an organic solvent which can be mixed with water is used, but when the solvent is replaced with a hydrophobic organic solvent, the pH is preferably measured in advance in a stage of a methanol solvent sol.

For example, as for a methanol sol, a propylene glycol monomethyl ether sol, and the like in which the dispersion medium is a hydrophilic organic solvent, a mass ratio of pure water to sol of 1:1, and a dispersion medium such as a methyl ethyl ketone sol of a hydrophobic organic solvent, wherein pure water, methanol and methyl ethyl ketone sol are mixed in a mass ratio of 1:1:1, and measuring the solution obtained by mixing.

The hollow silica organic solvent sol is subjected to solvent substitution of an aqueous medium with an alcohol solvent having 1 to 5 carbon atoms and further with an organic solvent, but water may remain in the process. In the stage of the alcohol sol of hollow silica, for example, the residual moisture may be contained in the sol in an amount of 0.1 to 3.0% by mass, or 0.1 to 1.0% by mass. Further, the hollow silica may be contained in an amount of 0.01 to 0.5% by mass in the stage of the organic solvent sol (the dispersion medium is an organic solvent other than alcohol).

In addition, the viscosity of the hollow silica organic solvent sol may be set to a range of 1.0 to 10.0mpa·s.

The hollow silica sol of the present invention may be added with an amine.

The amine used in the present invention may be a water-soluble amine having a water solubility of 80g/L or more or 100g/L or more.

The hollow silica aqueous sol as a raw material and the hollow silica organic solvent sol obtained by solvent substitution may contain an amine, or an amine and ammonia. The amine may be added in a range of 0.001 to 10 mass%, or 0.01 to 10 mass%, or 0.1 to 10 mass% relative to SiO ₂ of the hollow silica particles. Further, the amine, or the amine and ammonia, may contain the alkali component in the hollow silica particle organic solvent sol in a total nitrogen amount, for example, in a range of 10 to 100000ppm, or 100 to 10000ppm, or 100 to 3000ppm, or 100 to 2000ppm, typically 200 to 2000 ppm.

Examples of the amine include aliphatic amines and aromatic amines, and aliphatic amines are preferably used. The amine may be at least 1 amine selected from primary, secondary and tertiary amines having 1 to 10 carbon atoms. These amines are water-soluble and are at least 1 amine selected from primary amines, secondary amines and tertiary amines having 1 to 10 carbon atoms.

Examples of the primary amine include monomethyl amine, monoethyl amine, monopropyl amine, monoisopropyl amine, monobutyl amine, monoisobutyl amine, mono-sec-butyl amine, mono-tert-butyl amine, monomethylol amine, monoethanolamine, monopropanol amine, monoisopropanolamine, monobutylamine, monoisobutolamine, mono-sec-butylamine, and mono-tert-butylamine.

Examples of the secondary amine include dimethylamine, diethylamine, dipropylamine, diisopropylamine, N-methylethylamine, N-ethylisobutylamine, dimethanolamine, diethanolamine, dipropanolamine, diisopropanolamine, N-methanol-ethylamine, N-methylethanolamine, N-ethanol-isobutylamine, and N-ethylisobutylamine.

Examples of the tertiary amine include trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, triisobutylamine, tri-sec-butylamine, tri-tert-butylamine, trimethylamine, triethanolamine, tripropanolamine, triisopropanolamine, tributylamine, triisobutanolamine, tri-sec-butanolamine, and tri-tert-butanolamine.

The water solubility of the amine is preferably 80g/L or more, or 100g/L or more. The amine is preferably a primary amine or a secondary amine, and is more preferably a secondary amine in view of low volatility and high solubility, and examples thereof include diisopropylamine and diethanolamine.

In the present invention, the surface charge amount per 1g of SiO ₂ converted hollow silica particles can be set to 5. Mu. Eq/g or more, or 25. Mu. Eq/g or more by containing the above amine. Typically, the amount is set to a range of 5 to 250. Mu. Eq/g, or 25 to 100. Mu. Eq/g, or 25 to 80. Mu. Eq/g.

In the present invention, the surface charge amount of the hollow silica particles can be adjusted to an arbitrary surface charge amount by adjusting the kind and the addition amount of the amine.

In the present invention, the surfaces of the hollow silica particles may be coated with a silane compound.

The silane compound may be coated with a hydrolysate of at least 1 silane compound selected from the group consisting of the above formulas (1) to (3).

In the above formula (1), R ¹ is each an alkyl group, a haloalkyl group, an alkenyl group, an aryl group, or an organic group having a polyether group, an epoxy group, a (meth) acryloyl group, a mercapto group, a amino group, a ureido group, or a cyano group and bonded to a silicon atom through a Si-C bond, R ² is each an alkoxy group, an acyloxy group, or a halogen group, a is an integer of 1 to 3,

In the formula (2) and the formula (3), R ³ and R ⁵ are each an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms and bonded to a silicon atom by a Si-C bond, R ⁴ and R ⁶ are each an alkoxy group, an acyloxy group or a halogen group, Y is 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.

The alkyl group is an alkyl group having 1 to 18 carbon atoms, examples thereof include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1-dimethyl-n-propyl, 1, 2-dimethyl-n-propyl, 2-dimethyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, 1-methyl-cyclobutyl, 2-methyl-cyclobutyl, 3-methyl-cyclobutyl, 1, 2-dimethyl-cyclopropyl, 2, 3-dimethyl-cyclopropyl 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1-dimethyl-n-butyl, 1, 2-dimethyl-n-butyl, 1, 3-dimethyl-n-butyl, 2-dimethyl-n-butyl, 2, 3-dimethyl-n-butyl, 3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1, 2-trimethyl-n-propyl, 1, 2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, 1-methyl-cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl-cyclobutyl, 2-ethyl-cyclobutyl, 3-ethyl-cyclobutyl, 1, 2-dimethyl-cyclobutyl, 1, 3-dimethyl-cyclobutyl, 2-dimethyl-cyclobutyl, 2, 3-dimethyl-cyclobutyl, 2, 4-dimethyl-cyclobutyl, 3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-isopropyl-cyclopropyl, 2-isopropyl-cyclopropyl, 1, 2-trimethyl-cyclopropyl, 1,2, 3-trimethyl-cyclopropyl, 2, 3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl and 2-ethyl-3-methyl-cyclopropyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, pentadecyl, heptadecyl, and the like, but are not limited thereto.

Further, examples of the alkylene group include alkylene groups derived from the above alkyl groups.

The aryl group is an aryl group having 6 to 30 carbon atoms, and examples thereof include phenyl, naphthyl, anthryl, pyrenyl, and the like.

The alkenyl group is an alkenyl group having 2 to 10 carbon atoms, examples thereof include vinyl, 1-propenyl, 2-propenyl, 1-methyl-1-vinyl, 1-butenyl, 2-butenyl, 3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylvinyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-n-propylvinyl, 1-methyl-1-butenyl, 1-methyl-2-butenyl, 1-methyl-3-butenyl, 2-ethyl-2-propenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, 2-methyl-3-butenyl, 3-methyl-1-butenyl, 3-methyl-2-butenyl, 3-methyl-3-butenyl, 1-dimethyl-2-propenyl, 1-isopropyl vinyl, 1, 2-dimethyl-1-propenyl, 1, 2-dimethyl-2-propenyl, 1, 2-cycloalkenyl, 2-hexenyl, 1-hexenyl, 2-hexenyl, 1-hexenyl, 3-hexenyl, 1-hexenyl and 5-cycloalkenyl, 1-methyl-2-pentenyl, 1-methyl-3-pentenyl, 1-methyl-4-pentenyl, 1-n-butylvinyl, 2-methyl-1-pentenyl, 2-methyl-2-pentenyl, and the like, but are not limited thereto.

Examples of the alkoxy group include an alkoxy group having 1 to 10 carbon atoms, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, 1-methyl-n-butoxy, 2-methyl-n-butoxy, 3-methyl-n-butoxy, 1-dimethyl-n-propoxy, 1, 2-dimethyl-n-propoxy, 2-dimethyl-n-propoxy, 1-ethyl-n-propoxy, and n-hexyloxy, but the present invention is not limited thereto.

Examples of the acyloxy group include methylcarbonyloxy, ethylcarbonyloxy, n-propylcarbonyloxy, isopropylcarbonyloxy, n-butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, n-pentylcarbonyloxy, 1-methyl-n-butylcarbonyloxy, 2-methyl-n-butylcarbonyloxy, 3-methyl-n-butylcarbonyloxy, 1-dimethyl-n-propylcarbonyloxy, 1, 2-dimethyl-n-propylcarbonyloxy, 2-dimethyl-n-propylcarbonyloxy, 1-ethyl-n-propylcarbonyloxy, n-hexylcarbonyloxy, 1-methyl-n-pentylcarbonyloxy, 2-methyl-n-pentylcarbonyloxy and the like.

Examples of the halogen atom include fluorine, chlorine, bromine, and iodine.

Examples of the organic group having a polyether group include a polyether propyl group having an alkoxy group. For example, (CH ₃O)₃SiC₃H₆(OC₂H₄)nOCH₃. N may be used in the range of 1 to 100, or 1 to 10).

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

The term "meth" acryl "refers to both acryl and methacryl. Examples of the organic group having a (meth) acryloyl group include a 3-methacryloxypropyl group and a 3-acryloxypropyl group.

Examples of the organic group having a mercapto group include a 3-mercaptopropyl group.

Examples of the organic group having an amino group include 2-aminoethyl group, 3-aminopropyl group, N-2- (aminoethyl) -3-aminopropyl group, N- (1, 3-dimethyl-butylene) aminopropyl group, N-phenyl-3-aminopropyl group, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyl group, and the like.

Examples of the organic group having an ureido group include 3-ureidopropyl group.

Examples of the organic group having a cyano group include a 3-cyanopropyl group.

The above formula (2) and formula (3) are preferably compounds capable of forming trimethylsilyl groups on the surfaces of silica particles.

These compounds are exemplified below.

In the above formula, R ¹² is an alkoxy group, and examples thereof include methoxy and ethoxy. As the silane compound, a silane compound manufactured by Xinyue chemical industries, ltd.

On the surface of the silica particles, hydroxyl groups, for example, silanol groups in the case of silica particles, may react with the silane compound and be bonded to the surface of the silica particles via siloxane bonds. The reaction temperature may be in the range of from 20℃to the boiling point of the dispersion medium, and may be in the range of from 20℃to 100 ℃. The reaction time may be about 0.1 to 6 hours.

The silane compound may be added to the silica sol in such a manner that the surface of the silica particles is coated with a coating amount of the silane compound corresponding to the number of silicon atoms in the silane compound of 0.1/nm ² to 6.0/nm ².

The hydrolysis of the silane compound requires water, and if it is a sol of an aqueous solvent, these aqueous solvents are used. The water remaining in the solvent when the aqueous medium solvent is replaced with the organic solvent can be used. For example, moisture present in 0.01 to 1 mass% can be used. The hydrolysis may be performed using a catalyst or may be performed without a catalyst.

The case where the catalyst is not used is a case where the surface of the silica particles is present on the acidic side (less than pH 7), and examples of the hydrolysis catalyst include metal chelates, organic acids, inorganic acids, organic bases, and inorganic bases. Examples of the metal chelate compound as the hydrolysis catalyst include titanium triethoxy mono (acetylacetonate) and zirconium triethoxy mono (acetylacetonate). Examples of the organic acid as the hydrolysis catalyst include acetic acid and oxalic acid. 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 1 selected from the group consisting of 2-valent aliphatic carboxylic acids, aliphatic hydroxycarboxylic acids, amino acids, and chelating agents, the 2-valent aliphatic carboxylic acids are oxalic acid, malonic acid, and succinic acid, the aliphatic hydroxycarboxylic acids are glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid, the amino acids are glycine, alanine, valine, leucine, serine, and threonine, and the chelating agents include ethylenediamine tetraacetic acid, L-aspartic acid-N, N-diacetic acid, and diethylenetriamine pentaacetic acid. Examples of the organic acid salt include alkali metal salts, ammonium salts, and amine salts of the above-mentioned organic acids. Examples of the alkali metal include sodium and potassium.

In the present invention, a composition for forming a coating film comprising the hollow silica organic solvent sol and an organic resin is obtained.

The organic resin is mixed with a thermosetting or photocurable resin to obtain a composition for forming a film. Further, it may contain 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) to prepare a cured product.

The composition can be used for forming a cured product by applying or filling a composition for forming a coating film containing an organic resin and a curing agent to a substrate, and heating, light irradiation, or a combination thereof. Examples of the organic resin (curable resin) include a resin having a functional group such as an epoxy group or a (meth) acryloyl group, and an isocyanate resin. For example, a photocurable polyfunctional acrylate can be preferably used.

Examples of the polyfunctional acrylate include polyfunctional acrylates having 2,3,4, and more functional groups in the molecule, and examples of the polyfunctional acrylates include neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

Examples of the polyfunctional acrylate include compounds represented by the following formulas.

The coating film-forming composition of the present invention may 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) may be added in the range of 0.01 to 5phr, or 0.01 to 1phr, with respect to the organic resin.

Examples of the anionic surfactant used in the present invention include sodium and potassium salts of fatty acids, alkylbenzenesulfonates, higher alcohol sulfate salts, polyoxyethylene alkyl ether sulfates, alpha-sulfofatty acid esters, alpha-olefin sulfonates, monoalkyl phosphate salts, and alkane sulfonates.

Examples of the alkylbenzene sulfonate include sodium salts, potassium salts and lithium salts, and examples thereof include sodium C10-C16 alkylbenzene sulfonate, sodium C10-C16 alkylbenzene sulfonate and sodium alkyl naphthalene sulfonate.

Examples of the higher alcohol sulfate include sodium dodecyl sulfate (sodium lauryl sulfate), triethanolamine lauryl sulfate, and triethanolamine lauryl sulfate having 12 carbon atoms.

The polyoxyethylene alkyl ether sulfate may be polyoxyethylene styrenated phenyl ether sodium sulfate, polyoxyethylene styrenated phenyl ether ammonium sulfate, polyoxyethylene decyl ether sodium sulfate, polyoxyethylene decyl ether ammonium sulfate, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether ammonium sulfate, polyoxyethylene tridecyl ether sodium sulfate, polyoxyethylene oleyl cetyl ether sodium sulfate, etc.

Examples of the alpha-olefin sulfonate include sodium alpha-olefin sulfonate.

Examples of the alkanesulfonate include sodium 2-ethylhexyl sulfate.

Examples of the cationic surfactant used in the present invention include alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzyl ammonium salt and amine salt-based agents.

The alkyl trimethylammonium salt is a quaternary ammonium salt, and has chloride ions and bromide ions as counter ions. Examples thereof include dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, cocoalkyltrimethylammonium chloride, and alkyl (C16-18) trimethylammonium chloride.

The dialkyldimethylammonium salt has 2 backbones and 2 methyl groups which become lipophilic. Bis (hydrogenated tallow) dimethyl ammonium chloride may be mentioned. Examples thereof include didecyldimethylammonium chloride, dicarbalkyldimethylammonium chloride, dithiinized tallow alkyl dimethylammonium chloride, and dialkyl (C14-18) dimethylammonium chloride.

The alkyldimethylbenzyl ammonium salt is a quaternary ammonium salt having 1,2 methyl or benzyl groups as a main chain which becomes lipophilic, and examples thereof include benzalkonium chloride. For example, alkyl (C8-18) dimethylbenzyl ammonium chloride may be mentioned.

The amine salt-based agent is obtained by substituting 1 or more hydrocarbon groups for the hydrogen atom of ammonia, and examples thereof include N-methyldihydroxyethylamine fatty acid ester hydrochloride.

The amphoteric surfactant used in the present invention includes an alkyl amino fatty acid salt of N-alkyl- β -alanine type, an alkyl betaine of alkyl carboxyl betaine type, and an alkyl amine oxide of N, N-dimethyl dodecyl amine oxide type. Examples thereof include lauryl betaine, stearyl betaine, and 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolineBetaine and lauryl dimethyl amine oxide.

The nonionic surfactant used in the present invention is selected from polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, alkyl glucoside, polyoxyethylene fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkanolamide. Examples of the polyoxyethylene alkyl ether include polyoxyethylene lauryl 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, and polyoxyethylene mountain etherAnd alkyl ethers, polyoxyethylene-2-ethylhexyl ethers, polyoxyethylene isodecyl ethers, and the like.

Examples of the polyoxyethylene alkylphenol ether include polyoxyethylene styrenated phenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene biphenyl styrenated phenyl ether, and polyoxyethylene tribenzylphenyl ether.

Examples of the alkyl glucosides include decyl glucoside and lauryl glucoside.

Examples of the polyoxyethylene fatty acid ester include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyethylene glycol distearate, polyethylene glycol dioleate, and polypropylene glycol dioleate.

As the fatty acid ester of sorbitan, is selected from sorbitan monocaprylate, sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, and sorbitan fatty acid ester sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan monoleate, and ethylene oxide adducts thereof, and the like.

Examples of the polyoxyethylene sorbitan fatty acid ester include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan triisostearate.

Further, fatty acid alkanolamides include coconut fatty acid diethanolamide, tallow fatty acid diethanolamide, lauric acid diethanolamide, oleic acid diethanolamide, and the like.

Further, polyoxyethylene polyoxypropylene glycol, polyoxyethylene alkyl ether such as polyoxyethylene fatty acid ester, polyoxyethylene alkyl glycol, 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.

Silicon-based surfactants may be used. The silicon surfactant is a compound having a main chain including a repeating unit of a siloxane bond. The weight average molecular weight of the silicon surfactant may be in the range of 500 to 50000. These may be modified silicon surfactants, and examples thereof include those having an organic group introduced into a side chain and/or a terminal of a polysiloxane. Examples of the organic group include an amino group, an epoxy group, an alicyclic epoxy group, a methanol 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 a silicone surfactant having a trade name of ,トーレシリコーンDC3PA、トーレシリコーンSH7PA、トーレシリコーンDC11PA、トーレシリコーンSH21PA、トーレシリコーンSH28PA、トーレシリコーンSH29PA、トーレシリコーンSH30PA、トーレシリコーンSH8400( or more, a compound of Dong and Kun コ or more, a compound of Kun and Kun, KF-6001, KF-6002 (made by Xin Yuan コ, a compound of Kun and Kun), a compound of BYK307, BYK323, and BYK330 (made by Kun and Kun). For example, polyether-modified silicone may be used suitably under the trade name L-7001 (manufactured by DOWSIL Co., ltd.).

In the present invention, a composition for forming a film comprising the above-mentioned organic solvent sol and an organic resin can be obtained. The composition for forming a coating film can be obtained by removing the organic solvent in the organic solvent sol to prepare a composition for forming a coating film containing hollow silica particles and an organic resin.

In the case of the thermosetting coating film-forming composition, the thermosetting agent may be added in an amount of 0.01 to 50phr, or 0.01 to 10phr, based on the resin having a functional group such as an epoxy group or a (meth) acryloyl group, and the thermosetting agent may be contained in a ratio of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, based on the functional group such as an epoxy group or a (meth) acryloyl group. The equivalent weight of the thermosetting agent to the curable resin is represented by the equivalent ratio of the thermosetting agent to the functional group.

Examples of the thermosetting agent include phenolic resins, amine-based curing agents, polyamide resins, imidazoles, polythiols, acid anhydrides, thermal radical generators, thermal acid generators, and the like. Particularly preferred are thermal radical generator-based curing agents, acid anhydride-based curing agents and amine-based curing agents.

These thermosetting agents may be used by dissolving them in a solvent, but since the density of the cured product is reduced by evaporation of the solvent and pores are formed, the strength is reduced and the water resistance is reduced, the curing agent itself is preferably liquid at ordinary temperature and pressure.

Examples of the phenolic resin include phenol novolac resins and cresol novolac resins.

Examples of the amine-based curing agent include piperidine, N-dimethylpiperazine, triethylenediamine, 2,4, 6-tris (dimethylaminomethyl) phenol, benzyldimethylamine, 2- (dimethylaminomethyl) phenol, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, bis (1-methyl-2-aminocyclohexyl) methane, menthylenediamine, isophoronediamine, diaminodicyclohexylmethane, 1, 3-diaminomethylcyclohexane, xylylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, 3 '-diethyl-4, 4' -diaminodiphenylmethane, and diethyltoluenediamine. Among them, liquid diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, bis (1-methyl-2-aminocyclohexyl) methane, menthylenediamine, isophoronediamine, diaminodicyclohexylmethane, 3 '-diethyl-4, 4' -diaminodiphenylmethane, diethyltoluenediamine, and the like can be preferably used.

The polyamide resin is produced by condensing a dimer acid with a polyamine, and is a polyamidoamine having a primary amine and a secondary amine in the molecule.

Examples of imidazoles include 2-methylimidazole, 2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-undecylimidazoleTrimellitates, epoxy imidazole adducts, and the like.

The polythiol is, for example, a substance having a thiol group at the end of a polypropylene glycol chain, or a substance having a thiol group at the end of a polyethylene glycol chain, and is preferably a liquid substance.

The acid anhydride-based curing agent is preferably an anhydride of a compound having a plurality of carboxyl groups in one molecule. Examples of the acid anhydride curing agent include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol ditrimethyltrimellitate, glycerol trimellitate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylene tetrahydrophthalic anhydride, methyl butenyl tetrahydrophthalic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methyl hexahydrophthalic anhydride, succinic anhydride, methylcyclohexene dicarboxylic anhydride, and chloric anhydride.

As the thermal acid generator, there may be mentioned sulfonium salts,Salts, but sulfonium salts are preferred. The following compounds may be exemplified, for example.

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

Among them, preferred are methyltetrahydrophthalic anhydride, methyl-5-norbornene-2, 3-dicarboxylic anhydride (methylnadic anhydride, methylnorbornenedicarboxylic anhydride), hydrogenated methylnadic anhydride, methylbutyl tetrahydrophthalic anhydride, dodecenylsuccinic anhydride, methylhexahydrophthalic anhydride, and a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride, which are liquid at ordinary temperature and ordinary pressure. The viscosity of these liquid anhydrides is about 10 mPas to 1000 mPas in the measurement at 25 ℃.

Examples of the thermal radical generator include 2,2' -azobis (isobutyronitrile), 2' -azobis (2-methylbutyronitrile), 2' -azobis (2, 4-dimethylvaleronitrile), 4' -azobis (4-cyanovaleric acid), dimethyl 2,2' -azobis (2-methylpropionate), 2' -azobis (2-methylpropionamidine) dihydrochloride, 2' -azobis [2- (2-imidazolin-2-yl) propane ] dihydrochloride, t-butyl hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, benzoyl peroxide, and the like. They are available from tokyo chemical industry (inc.).

In addition, in obtaining the above-mentioned cured product, a curing aid may be used in combination as appropriate. Examples of the curing aid include organophosphorus compounds such as triphenylphosphine and tributylphosphine, and ethyltriphenyl bromideMethyl triphenylQuaternary ammonium such as diethyl phosphateSalts, salts of 1, 8-diazabicyclo (5, 4, 0) undec-7-ene with octanoic acid, quaternary ammonium salts such as zinc octanoate and tetrabutylammonium bromide. These curing aids may be contained in a proportion of 0.001 to 0.1 part by mass relative to 1 part by mass of the curing agent.

The composition is obtained in the form of a thermosetting varnish by mixing a resin, a curing agent and a curing auxiliary agent as required. The mixing may be performed in the reaction vessel using a stirring blade or a kneader.

The mixing is carried out by a heating mixing method, and the mixing is carried out at a temperature of 60-100 ℃ for 0.5-1 hour.

The obtained curable film-forming composition is a thermosetting coating composition, and has, for example, an appropriate viscosity for use as a liquid sealing material. The liquid thermosetting coating composition can be prepared to have an arbitrary viscosity, and can be partially sealed at an arbitrary position by a casting method, a pouring method, a dispenser method, a printing method, or the like for use as a transparent sealing material for LEDs or the like. The liquid thermosetting composition is directly applied to an LED or the like in a liquid state by the above method, and then dried and cured to obtain an epoxy resin cured body.

The thermosetting coating composition (thermosetting coating composition) is applied to a substrate and heated at a temperature of 80 to 200 ℃ to obtain a cured product.

In the case where the film-forming composition is a photocurable resin composition, the photocurable agent (photo radical generator, photoacid generator) may be added in an amount of 0.01 to 50phr, or 0.01 to 10phr, based on the resin having a functional group such as an epoxy group or a (meth) acryloyl group, and for example, the photocurable agent (photo radical generator, photoacid generator) may be contained in an amount of 0.5 to 1.5 equivalents, preferably 0.8 to 1.2 equivalents, based on the functional group such as an epoxy group or a (meth) acryloyl group. The equivalent weight of the photocurable agent to the curable resin is represented by the equivalent ratio of the photocurable agent to the functional group.

The photoradical generator is not particularly limited as long as it directly or indirectly generates radicals by light irradiation.

Examples of the photo-radical polymerization initiator among the photo-radical generators include imidazole compounds, diazo compounds, bisimidazole compounds, N-arylglycine compounds, organic azide compounds, titanocene compounds, aluminate compounds, organic peroxides, N-alkoxypyridinesSalt compounds, thioxanthone compounds, and the like. Examples of the azide compound include p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzophenone, 4' -diazidochalcone, 4' -diazidodiphenyl sulfide, and 2, 6-bis (4 ' -azidobenzene) -4-methylcyclohexanone. Examples of the diazonium compound include 1-diazonium-2, 5-diethoxy-4-p-tolylthiobenzene boron fluoride, 1-diazonium-4-N, N-dimethylaminobenzene chloride, and 1-diazonium-4-N, N-diethylaminobenzene boron fluoride. 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 dicyclopentadiene-titanium-dichloride, dicyclopentadiene-titanium-bisphenyl, dicyclopentadiene-titanium-bis (2, 3,4,5, 6-pentafluorophenyl), dicyclopentadiene-titanium-bis (2, 3,5, 6-tetrafluorophenyl), dicyclopentadiene-titanium-bis (2, 4, 6-trifluorophenyl), dicyclopentadiene-titanium-bis (2, 6-difluorophenyl), dicyclopentadiene-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 dicyclopentadiene-titanium-bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) -phenyl).

Examples of the photoradical generator include 1, 3-di (t-butyldioxycarbonyl) benzophenone, 3', 4' -tetra (t-butyldioxycarbonyl) benzophenone, and 3-phenyl-5-iso-formOxazolone, 2-mercaptobenzimidazole, 2-dimethoxy-1, 2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-one, and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, and the like.

These photo radical polymerization agents are available, for example, from BASF, under the trade name Irgacure TPO (component 2,4, 6-trimethylbenzoyl diphenyl phosphine oxide) (c 1-1-1), from IGM RESINS, under the trade name Omnirad819 (component bis (2, 4, 6-trimethylbenzoyl) phenyl phosphine oxide) (c 1-1-2), from IGM RESINS, and under the trade name Irgacure 184 (component 1-hydroxycyclohexyl phenyl ketone) (c 1-1-3).

The photoacid generator is not particularly limited as long as it directly or indirectly generates acid by light irradiation.

Specific examples of the photoacid generator include triazine compounds, acetophenone derivative compounds, disulfone compounds, diazomethane compounds, sulfonic acid derivative compounds, and iodineSalts, sulfonium salts,Salts, selenium salts, and the likeSalts, metallocene complexes, iron arene complexes, and the like.

Regarding the use as the photoacid generatorSalt as iodineExamples of the salt include diphenyliodideChloride, diphenyl iodideTrifluoromethane sulfonate and diphenyl iodideMethanesulfonate salt, diphenyl iodideToluene sulfonate, diphenyl iodideBromide, diphenyl iodideTetrafluoroborate and diphenyl iodideHexafluoroantimonate, diphenyliodineHexafluoroarsenate, bis (p-tert-butylphenyl) iodideHexafluorophosphate, bis (p-tert-butylphenyl) iodideMethanesulfonate salt, bis (p-tert-butylphenyl) iodideTosylate, bis (p-tert-butylphenyl) iodideTrifluoromethane sulfonate, bis (p-tert-butylphenyl) iodideTetrafluoroborate, bis (p-tert-butylphenyl) iodoChloride, bis (p-chlorophenyl) iodineChloride, bis (p-chlorophenyl) iodineTetrafluoroborate, further bis (4-t-butylphenyl) iodoBis (alkylphenyl) iodides such as hexafluorophosphateSalts, alkoxycarbonylalkoxy-trialkylaryl iodidesSalts (e.g., 4- [ (1-ethoxycarbonyl-ethoxy) phenyl ] - (2, 4, 6-trimethylphenyl) -iodoHexafluorophosphate, etc.), bis (alkoxyaryl) iodidesSalts (e.g., (4-methoxyphenyl) phenyliodide)Bis (alkoxyphenyl) iodides such as hexafluoroantimonateSalts).

Examples of the sulfonium salt include sulfonium salts such as triphenylsulfonium chloride, triphenylsulfonium bromide, tris (p-methoxyphenyl) sulfonium tetrafluoroborate, tris (p-methoxyphenyl) sulfonium hexafluorophosphonate, tris (p-ethoxyphenyl) sulfonium tetrafluoroborate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate and the like, (4-phenylsulfanylphenyl) diphenylsulfonium hexafluoroantimonate, (4-phenylsulfanylphenyl) diphenylsulfonium hexafluorophosphate, bis [4- (diphenylsulfoninyl) phenyl ] sulfide-bis-hexafluoroantimonate and (4-methoxyphenyl) diphenylsulfonium hexafluoroantimonate.

As a means ofExamples of the salt include triphenylchlorideTriphenyl brominationTris (p-methoxyphenyl)Tetrafluoroborate, tris (p-methoxyphenyl)Hexafluorophosphonate, tris (p-ethoxyphenyl)Tetrafluoroborate, 4-chlorobenzenediazoniumHexafluorophosphate, benzyl triphenylHexafluoroantimonate and the likeAnd (3) salt.

Examples thereof include selenium salts such as triphenylselenohexafluorophosphate and metallocene complexes such as (. Eta.5 or. Eta.6-isopropylbenzene (. Eta.5-cyclopentadienyl) iron (II) hexafluorophosphate.

In addition, as the photoacid generator, the following compounds may also be used.

As the photoacid generator, sulfonium salt compounds and iodine are preferableA salt compound. Examples of the anionic species include CF₃SO₃ ^-、C₄F₉SO₃ ^-、C₈F₁₇SO₃ ^-、 camphor sulfonate anion, toluene sulfonate anion, BF ₄ ^-、PF₆ ^-、AsF₆ ^- and SbF ₆ ^-. Particularly preferred are anionic species such as phosphorus hexafluoride and antimony hexafluoride which exhibit strong acidity.

The composition for forming a coating film of the present invention may contain conventional additives as required. Examples of such additives include pigments, colorants, thickeners, sensitizers, defoamers, coatability improvers, lubricants, stabilizers (antioxidants, heat stabilizers, light stabilizers, etc.), plasticizers, dissolution accelerators, fillers, antistatic agents, and the like. These additives may be 1 or2 or more in combination.

Examples of the coating method of the coating 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, and a slit method.

In the present invention, the light-applied composition (coating film-forming composition) may be applied to a substrate and cured by irradiation with light. Heating may be performed before and after the light irradiation.

The thickness of the coating film may be selected from the range of about 0.01 μm to 10mm depending on the application of the cured product, and may be about 0.05 μm to 10 μm (particularly 0.1 μm to 5 μm) in the case of use in a photoresist, about 5 μm to 5mm (particularly 100 μm to 1 mm) in the case of use in a printed wiring board, and about 0.1 μm to 100 μm (particularly 0.3 μm to 50 μm) in the case of use in an optical film, for example.

In the case of obtaining a transparent coating film, the visible light transmittance of the coating film may be 80% or more, or 90% or more, typically 90 to 96%.

The light to be irradiated or exposed in the case of using the photoacid generator may be, for example, gamma rays, X rays, ultraviolet rays, visible light or the like, and is usually visible light or ultraviolet rays, particularly ultraviolet rays in many cases. The wavelength of light is, for example, 150 to 800nm, preferably 150 to 600nm, and more preferably about 150 to 400 nm. The irradiation light amount varies depending on the thickness of the coating film, but may be, for example, 2 to 20000mJ/cm ², preferably about 5 to 5000mJ/cm ². The light source may be selected according to the type of light to be exposed, and for example, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a deuterium lamp, a halogen lamp, a laser (helium-cadmium laser, excimer laser, or the like) or the like may be used in the case of ultraviolet rays. By such light irradiation, the curing reaction of the composition proceeds.

When a thermal acid generator is used, the coating film is heated as needed after light irradiation using the photoacid generator, for example, at about 60 to 350 ℃, preferably about 100 to 300 ℃. The heating time may be selected from a range of 3 seconds or more (for example, about 3 seconds to 5 hours), and may be performed for about 5 seconds to 2 hours, preferably about 20 seconds to 30 minutes, and may be performed for about 1 minute to 3 hours (for example, about 5 minutes to 2.5 hours).

Further, in the case of forming a pattern or an image (for example, in the case of manufacturing a printed wiring board or the like), a coating film formed on a substrate may be subjected to pattern exposure by scanning with a laser beam or by irradiation with light through a photomask. The non-irradiated region (non-exposed portion) generated by the pattern exposure is developed (or dissolved) with a developer, whereby a pattern or an image can be formed.

As the developer, an alkaline aqueous solution or an organic solvent can be used.

Examples of the alkaline aqueous 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 tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide and choline, and aqueous solutions of amines such as ethanolamine, propylamine and ethylenediamine.

The alkaline developer is usually an aqueous solution of 10 mass% or less, preferably 0.1 to 3.0 mass% aqueous solution. The alcohol and the surfactant may be further added to the developer, and they may be used in an amount of preferably 0.05 to 10 parts by mass per 100 parts by mass of the developer.

Among them, a tetramethyl ammonium hydroxide aqueous solution of 0.1 to 2.38 mass% can be used.

The organic solvent used for the developer may be any general organic solvent, and examples thereof include 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, and cyclohexanone, and may be used as a mixture of 1 or2 or more of them. In particular, propylene glycol methyl ether acetate, ethyl lactate, and the like can be preferably used.

In the present invention, an adhesion promoter may be added for the purpose of improving adhesion to a substrate after development. Examples of the adhesion promoter include chlorosilanes such as trimethylchlorosilane, dimethylvinylchlorosilane, methyldiphenylchlorosilane, chloromethyldimethylchlorosilane, etc., silanes such as trimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, dimethylvinylethoxysilane, alkoxysilane such as diphenyldimethoxysilane, phenyltriethoxysilane, hexamethyldisilazane, N' -bis (trimethylsilyl) urea, dimethyltrimethylsilylamine, silazanes such as trimethylsilylimidazole, vinyltrichlorosilane, 3-chloropropyltrimethoxysilane, 3-aminopropyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, silanes such as 3- (N-piperidinyl) propyl trimethoxysilane, benzotriazole, benzimidazole, indazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoimidazole, etcHeterocyclic compounds such as oxazole, uracil, thiouracil, mercaptoimidazole and mercaptopyrimidine, ureas such as 1, 1-dimethylurea and 1, 3-dimethylurea, or thiourea compounds. The adhesion promoter may be used alone or in combination of 2 or more of them. The amount of the adhesion promoter to be added is usually 18% by mass or less, preferably 0.0008 to 9% by mass, more preferably 0.04 to 9% by mass, based on the solid content.

Sensitizers may be included in the present invention. Examples of the sensitizer that can be used include anthracene, phenothiazine, perylene, thioxanthone, benzophenone thioxanthone, and the like. Further, as the sensitizing dye, thiopyran can be exemplifiedSalt-based coloring matter, merocyanine-based coloring matter, quinoline-based coloring matter, styryl quinoline-based coloring matter, coumarin-based coloring matter, thioxanthene-based coloring matter,Xanthene pigments, oxonol pigments, cyanine pigments, rhodamine pigments, pyran pigmentsSalt pigments, and the like. Particularly preferred are anthracene-based sensitizers, which are used in combination with a cationic curing catalyst (radiation-sensitive cationic polymerization initiator) to dramatically improve the sensitivity and have a radical polymerization initiating function, and the type of catalyst can be simplified by combining the cationic curing system and the radical curing system of the present invention. As specific anthracene compounds, dibutoxyanthracene, dipropoxyanthraquinone, and the like are effective. The sensitizer is added in an amount of 0.01 to 20% by mass, preferably 0.01 to 10% by mass, to the solid content.

The composition of the present invention can be photo-cured or thermally cured using a photo-radical generator, a thermal radical generator, a photoacid generator, or a thermal acid generator. In the case of using a photoacid generator or a thermal acid generator, for example, a curing agent (for example, an amine or an acid anhydride) of an epoxy which is usually used is not used or even if these are used, the content thereof is extremely small, and therefore the storage stability of the composition of the present invention is improved.

The above composition was found to be suitable for photo-cationic polymerization. Has a higher curing rate than the conventional liquid epoxy compound (for example, alicyclic epoxy compound having an epoxycyclohexyl ring). The addition amount of the acid generator can be reduced and the weak acid generator can be used because of the high curing speed. Sometimes acid active species remain after UV irradiation, reducing acid generators is important to prevent metal corrosion. Thick film curing is possible because of the high curing speed.

Curing by UV irradiation can be applied to materials (mechanical materials) that are not heat resistant.

The thermosetting material and the photocurable material using the composition for forming a coating film of the present invention have characteristics such as rapid curability, transparency, and small cure shrinkage, and can be used for coating and bonding electronic parts, optical parts (antireflection films), and precision mechanism parts. For example, the adhesive can be used for bonding optical elements such as a lens of a mobile phone or a camera, a Light Emitting Diode (LED), a semiconductor Laser (LD), a liquid crystal panel, a biochip, a lens of a camera, a prism, a magnetic part of a hard disk of a personal computer, a pickup (a part for introducing light information reflected from a magnetic disk) of a CD or DVD player, a cone and a coil of a speaker, a magnet of a motor, a circuit board, an electronic part, a part inside an engine of an automobile, and the like.

As a hard coating material for protecting surfaces of automobile bodies, lamps, electric appliances, building materials, plastics, etc., there are applications to, for example, automobile bodies, bicycle bodies, lenses for headlamps, mirrors, plastic lenses for glasses, mobile phones, game machines, optical films, ID cards, etc.

Examples of the ink material to be printed on metal such as aluminum or plastic include applications to cards such as credit cards and membership cards, switches for electrical appliances and OA equipment, inks for printing on keyboards, and inks for inkjet printers such as CDs and DVDs.

Examples of the application include application to optical modeling such as molding of industrial products, application to optical fibers, application to adhesion, optical waveguides, and application to thick film resists, etc., in which a resin is cured in combination with 3-dimensional CAD to produce a complex three-dimensional object.

The composition for forming a coating film of the present invention can be suitably used as an insulating resin for electronic materials such as an antireflection film, a semiconductor sealing material, an adhesive for electronic materials, a printed wiring board material, an interlayer insulating film material, and a sealing material for power modules, an insulating resin for high-voltage devices such as a generator coil, a transformer coil, and a gas-insulated switchgear.

The hollow silica sol of the present invention can be produced by including the following steps (I) and (II).

(I) The working procedure comprises the following steps: a step of preparing an aqueous sol of hollow silica,

(II) procedure: and (3) adding an aluminum compound to the hollow silica aqueous sol obtained in the step (I) in an amount of 0.0001 to 0.5g per 1g of hollow silica particles in terms of Al ₂O₃, and heating the mixture at 40 to 260 ℃ for 0.1 to 24 hours. The aluminum compound in the step (II) may be added in an amount of 0.0001 to 0.5g, or 0.001 to 0.1g, or 0.001 to 0.05g, in terms of Al ₂O₃ per 1g of the hollow silica particles. The heating temperature in the step (II) is 40 to 260℃or 50 to 260℃or 60 to 240℃but may be 40 to less than 100℃or 50 to less than 100℃or 60 to less than 100℃in the case of non-hydrothermal treatment, and may be 100 to 260℃or 150 to 240℃in the case of hydrothermal treatment. The heating time in the step (II) may be in the range of 0.1 to 48 hours, or 0.1 to 24 hours, or 0.1 to 10 hours, or1 to 10 hours.

The hollow silica particles used in the step (I) have a silica shell, and a space is provided inside the shell. Hollow silica is obtained by a method of forming a shell containing silica as a main component 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. Examples of the template include a method using an organic substance (e.g., hydrophilic organic resin particles such as polyethylene glycol, polystyrene, and polyester) and a method using an inorganic substance (e.g., hydrophilic inorganic compound particles such as calcium carbonate and sodium aluminate).

(I) The hollow silica aqueous sol to be used as a raw material in the step may be a non-hydrothermally treated hollow silica aqueous sol obtained by subjecting an aqueous medium to a heating temperature of less than 100 ℃, for example, 20 to less than 100 ℃, or 40 to less than 100 ℃, or 50 to less than 100 ℃.

The hollow silica aqueous sol used in the step (I) may be a hollow silica aqueous sol obtained by subjecting the hollow silica aqueous sol to a heating temperature of 100 to 240 ℃ or 110 to 240 ℃ in an aqueous medium.

The hollow silica sol as a raw material used in the present invention may be a non-hydrothermally treated hollow silica aqueous sol, a hydrothermally treated hollow silica aqueous sol, or a mixture thereof. In this method, aluminosilicate sites are formed on the outer shell of the hollow silica particles, but since the aluminosilicate sites sometimes hold alkali metals, the hollow silica sol as a raw material can be selected on the basis of bonding of aluminum atoms to the surfaces of the hollow silica particles in a ratio of 100 to 20000ppm/SiO ₂ to 1g SiO ₂ in terms of Al ₂O₃ conversion in the measurement by the leaching method.

In the step (II), an aluminum compound is added to the hollow silica aqueous sol obtained in the step (I). The aluminum compound may be added as a solid or as an aqueous solution to the hollow silica aqueous sol obtained in the step (I).

When the aluminum compound is impregnated from the outside after the formation of the hollow silica particles, there are a case where the hollow silica particles having an increased density of the shell are impregnated with the aluminum compound by the heat treatment before the impregnation of the hollow silica particles, and a case where the hollow silica particles not previously subjected to the hydrothermal treatment are impregnated with the aluminum compound by the heat treatment. In both the former case and in the latter case, it is preferable that aluminum atoms which can be measured by the leaching method are present in a specific ratio relative to silica.

The aluminum compound used in the step (II) is at least 1 selected from the group consisting of aluminates, aluminum alkoxides, and hydrolysates thereof, and may be used in the form of an aqueous solution containing them. Examples of aluminates include sodium aluminate, potassium aluminate, calcium aluminate, magnesium aluminate, ammonium aluminate, and amine aluminate salts. Examples of the aluminum alkoxide include aluminum isopropoxide and aluminum butoxide. In particular, aluminates can be preferably used.

These aluminum compounds are added as an aqueous solution to the hollow silica aqueous sol obtained in the step (I), and the concentration of the aqueous solution of the aluminum compound is used in the range of 0.01 to 20 mass%, or 0.1 to 10 mass%, or 0.5 to 5 mass%. The addition can be performed with stirring of the hollow silica aqueous sol obtained in the step (I). The addition may be performed before the heating, or may be performed entirely during the heating time.

The impregnation of the hollow silica particles with the aluminum compound in the desired amount depends on the treatment temperature in the step (II), and it is necessary to perform a heat treatment in the above temperature range.

The step (II) may include a step (II-i) of further adding an amine. The amine may be added to the hollow silica sol and may be contained in the above range.

The step (II) may include the steps of: and (II-II) a step of containing a neutral salt composed of a combination of at least 1 kind of cations composed of sodium ions, potassium ions and ammonium ions and inorganic anions or organic anions in a proportion of 0.1 to 10 mass% relative to SiO ₂ of the hollow silica particles.

The inorganic anion used in the step (II-II) is a sulfate ion, chloride ion or phosphate ion, and the organic anion may be exemplified by carboxylate ion, hydroxycarboxylate ion or amino acid. Examples of the preferable neutral salt include sodium sulfate, potassium sulfate, ammonium sulfate, and the like.

The step (II) may include the steps of: a step of adding the aluminum compound or the aluminum compound and at least 1 additive selected from the group consisting of an amine and a neutral salt to the hollow silica aqueous sol and heating the hollow silica aqueous sol; and a subsequent step of contacting the cation exchange resin with (II-iii), a step of adding an acid (II-iv), or a combination thereof. The cation exchange resin is a strong acid cation exchange resin of H-type, and may be contacted with an anion exchange resin thereafter. The acid may be added with inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, etc., or organic acid such as citric acid, acetic acid, malic acid, lactic acid, succinic acid, tartaric acid, butyric acid, fumaric acid, propionic acid, formic acid, etc.

In the present invention, the step (II) may include the steps of: a step of adding the aluminum compound (for example, sodium aluminate) and heating at 100 to 240 ℃ for 0.1 to 48 hours; and a subsequent step (II-v) of adding an acid (e.g., sulfuric acid, nitric acid, hydrochloric acid) to bring it into contact with the cation exchange resin. The leaching operation of adding the acid to dissolve the aluminum-containing component not doped into the particles and the metal impurities contained in the particles in the liquid by the heating step may further include the following steps of: and (II-vi) heating and curing at 40-100 ℃ for 0.1-48 hours, and then contacting the mixture with a cation exchange resin again.

After the completion of the step (II), the method may further comprise the steps of: and (III) a step of replacing the aqueous medium in the hollow silica sol with a C1-10 alcohol, a C1-10 ketone, a C1-10 ether, or a C1-10 ester.

After the completion of the step (III), the method may further comprise the steps of: and (IV) adding and heating at least 1 silane compound selected from the group consisting of the above formulas (1), (2) and (3).

The steps (III) and (IV) may be steps of adding at least 1 silane compound selected from the formulae (1), (2) and (3) to the hollow silica sol after the completion of the step (II) to replace the aqueous medium of the hollow silica sol with an alcohol having 1 to 10 carbon atoms in the step (III), heating the mixture, and replacing the mixture with a ketone having 1 to 10 carbon atoms, an ether having 1 to 10 carbon atoms, or an ester having 1 to 10 carbon atoms in the step (IV).

By using the above-described method for producing a hollow silica sol, the surface charge of the hollow silica particles contained in the sol can be adjusted.

Examples

(Determination of silica concentration)

The hollow silica sol was precisely weighed in a crucible, dried by heating at a temperature higher than the boiling point of the dispersion medium by about 10 ℃ on a hot plate to remove the solvent, and then the obtained silica gel was baked at 1000 ℃, and the remaining baked components were measured to calculate the silica concentration.

(Measurement of moisture)

The moisture of the organic solvent dispersion sol was measured by karl fischer titration.

(Measurement of viscosity)

The measurement was carried out at 25℃using a type B-II viscometer (manufactured by DONGCHINESE CORPORATION).

(Determination of pH)

The reaction mixture was measured at 25℃using a pH meter (manufactured by Toshidi, inc.).

Regarding the methanol sol, propylene glycol monomethyl ether sol, and the like of the organic solvent that can be optionally mixed with water, a mass ratio of pure water to sol of 1:1, and an organic solvent sol having a low solubility in water, such as methyl ethyl ketone sol, is prepared by mixing pure water, methanol, and the organic solvent sol in a mass ratio of 1:1:1, and measuring the solution obtained by mixing.

(Measurement of average particle diameter of hollow silica particles by DLS (dynamic light scattering method))

The hollow silica sol was diluted with a solvent used as a dispersion medium, and the average particle diameter of the hollow silica particles was measured by a dynamic light scattering particle diameter measuring apparatus (zebra, ltd.).

(Measurement of specific surface area of hollow silica particles by BET (Nitrogen adsorption method))

The cationic component in the hollow silica sol was removed by an H-type cation exchange resin, and the dried product obtained by removing the solvent by heat treatment was crushed by a mortar and further treated at 250℃for 2 hours. The specific surface area of the dried pulverized product was measured by the b.e.t.1 spot method using a gas adsorption specific surface area measuring apparatus (Quantachrome INSTRUMENTS, product of Monosorb TM MS-22) with a mixed gas of 30% N ₂ (nitrogen) and 70% He (helium) as a carrier gas.

(Measurement of average primary particle diameter of hollow silica particles by TEM (Transmission Electron microscope))

Particles in the hollow silica sol were photographed by a transmission electron microscope (JEM-F200, manufactured by japan electronics, inc.) and the average primary particle diameter (HEYWOOD diameter) of the hollow silica particles was measured by binarizing about 300 arbitrarily selected particles by an automatic image processing analysis device (LUZEX AP, manufactured by コ).

(Measurement/dissolution method of aluminum amount (B) in the hollow silica particles as a whole)

The precisely weighed hollow silica sol was dried, and the silica component was removed by treatment with a hydrofluoric acid solution, so that the residue was dissolved in a nitric acid aqueous solution. The amount of aluminum in the obtained aqueous solution was measured by an ICP emission analyzer, and the amount of aluminum present in the entire hollow silica particles was converted into Al ₂O₃ to obtain a ratio (Al ₂O₃(ppm)/SiO₂) of 1g SiO ₂ to the hollow silica particles.

(Determination of the amount of aluminum bonded to the surface of hollow silica particles/leaching method)

The cation component in the hollow silica sol was removed by an H-type cation exchange resin, and the dried product obtained by removing the solvent by heat treatment was crushed by a mortar and further treated at 250℃for 2 hours. Into a polypropylene container (50 mL of PP flask) containing 20mL of an aqueous solution of 0.1 mol/L (N/10) nitric acid, 0.2g of the obtained powder was charged, and the mixture was vigorously shaken by hand. Next, ultrasonic treatment was performed for 10 minutes by using an ultrasonic CLEANER (ASU CLEANER ASU-10M manufactured by Aristolon), so that the powder was sufficiently fused with the aqueous nitric acid solution. The mixture was put into a constant temperature bath at 50℃for 17 hours. Then, the inner solution was cooled to room temperature, and the solution was put into a centrifugal ultrafiltration filter (Amicon Ultra-15, molecular weight cut-off: 1 ten thousand), and subjected to centrifugation, and the amount of aluminum in the obtained filtrate was measured by an ICP emission analyzer, and the amount of aluminum bonded to the surfaces of the hollow silica particles was converted into Al ₂O₃ to obtain a ratio (Al ₂O₃(ppm)/SiO₂) of 1g SiO ₂ to the hollow silica particles.

(Measurement of surface Charge amount of hollow silica particles)

The hollow silica sol was added to and diluted with 10mL of methanol so that the silica concentration became about 0.5 mass%, and the mixture was used as a measurement sample. The titration value of the sample for measurement until the flow potential became zero was measured by a particle charge meter (brand name PCD-06, manufactured by fem corporation) using 0.001 mol/liter (N/1000) DADMAC solution (manufactured by fem corporation) as a cation standard titration solution. The value converted to 1g of hollow silica particles by dividing the obtained titration value by the mass of silica contained in the sample for measurement was set as the surface charge amount (μeq/g-SiO ₂). It should be noted that the number of the substrates, DADMAC means diallyldimethylammonium chloride.

(Calculation of specific surface area ratio (C/D))

The BET specific surface area value was divided by the specific surface area value calculated from spherical particles whose TEM average particle diameter was assumed to be true density 2.2g/cm ³, and the obtained value was defined as the specific surface area ratio.

(Measurement of refractive index of hollow silica particles)

Measured by the following steps 1) to 3).

1) Preparation of hollow silica aqueous sol compounding varnish

20.00G of 3-glycidoxypropyl trimethoxysilane (SILQUEST A-187T, manufactured by Kyoto Seamantadine Co., ltd.) was weighed into a plastic container, 18.57g of methanol and 4.57g of 0.01N aqueous hydrochloric acid were added thereto, and the mixture was stirred at room temperature for 5 hours. 6.00g of a methanol solution (10 mass% Al (acac) ₃) of previously prepared aluminum 2, 4-glutaronic acid (Al (acac) ₃) was added as a curing agent, and stirred for 10 minutes, thereby preparing a partial hydrolysate (concentration: 43 mass%) of 3-glycidoxypropyl trimethoxysilane (GPS).

The prepared partial hydrolysate of GPS, water, methanol, and a methanol solution (10 mass% L-7604) of a leveling agent (DOWSIL trademark L-7604) were weighed into a brown bottle so that the total amount of the solvent was 25.00g, the final solvent composition was water/methanol=9/1, and the mixing amount of SiO ₂ of the hollow silica aqueous sol was 50phr, 100phr, and 150phr, and stirred at room temperature for 30 minutes to prepare a hollow silica aqueous sol mixed varnish (solid content concentration: 4 mass%, mixing amount of SiO ₂: 50phr, 100phr, and 150 phr).

2) Preparation of hollow silica particle-blended film

Compounding the hollow silica aqueous sol obtained in 1) with a varnish (compounding amount (SiO ₂): 50phr, 100phr, 150 phr) was added dropwise to the UV-O3 treated Si substrate by about 1mL, and the mixture was uniformly spread on the Si substrate by using a spin coater (Wan, optical coat MS-B100) under conditions of rising to 200rpm at 2 seconds, 200rpm×10 seconds, rising to 800rpm at 2 seconds, 800rpm×5 seconds, and falling to 0rpm at 5 seconds. Then, the hollow silica particle-mixed film (mixing amount of SiO ₂: 50phr, 100phr, 150 phr) was prepared by baking at 80℃for 5 minutes on a hot plate and heat-treating at 120℃for 1 hour in an oven.

3) Refractive index measurement of hollow silica particle-mixed film, and refractive index calculation of hollow silica particle

Multiple incident angle spectroscopic ellipsometry (a strain) by ellipsometer (a strain) and a strain of direction and direction; polarimeter VASE) measured the mixing amount of the hollow silica particle mixed film obtained in 2) (SiO ₂: 50phr, 100phr, 150 phr). The refractive index of a film containing no hollow silica particles, which was prepared similarly using only a partial hydrolysate of GPS separately, was also measured. The refractive index of the hollow silica particles was obtained by plotting the measured refractive index of the mixed film against the mixed amount of the hollow silica particles and extrapolation so that the mixed amount of the hollow silica particles became 100 mass%.

Example 1

(1) Preparation of Water-Dispersion Sol (a) containing hollow silica particles of aluminum

A commercially available hollow silica aqueous sol [ Ningbo Dilato (trade name) HKT-A20-40 (a substance having undergone a heating temperature of less than 100 ℃ C. In an aqueous medium at the time of production of the hollow silica aqueous sol), 19.7 mass% SiO ₂, pH8.8, an average particle diameter of 54nm as measured by the DLS method, a specific surface area (C) of 145m ²/g as measured by the BET method, an aluminum amount (A) bonded to the particle surface was 0.1ppm in terms of Al ₂O₃ relative to 1g SiO ₂ of hollow silica particles, an aluminum amount (B) present in the whole particles was 0.5ppm in terms of Al ₂O₃ relative to 1g SiO ₂ of hollow silica particles, an average primary particle diameter (A/B ratio) was 0.20 as measured by TEM, an average primary particle diameter 46nm as measured by TEM, a specific surface area (D) of 59m ²/g as measured by the DLS method, a specific surface area ratio (C/D ratio) was 2.5, a refractive index of 1.30 g of particles was added to a container, and stirred, a solution of aqueous solution of sodium aluminate solution having a concentration of 35% by mass of sodium aluminate (35% was further diluted by dropping sodium aluminate solution of 35.35% in terms of 35 minutes was further stirred.

800G of the above mixture was charged into a glass-made separable flask, and the flask was heated at 80℃for 5 hours, and cooled to room temperature. Next, a column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (a) of hollow silica particles containing aluminum. The physical properties were 16.9 mass% as SiO ₂, pH2.6, average particle diameter of 54nm as measured by DLS method, specific surface area (C) 149m ²/g as measured by BET method, aluminum content (A) 1500ppm as bonded to the particle surface, aluminum content (B) 1900ppm as present in the whole particle, average primary particle diameter of 0.79 as measured by TEM, average primary particle diameter of 43nm as measured by TEM, TEM converted specific surface area (D) 63m ²/g, specific surface area ratio (C/D) 2.4, refractive index of 1.26, and thickness of the shell of 6.7nm.

(2) Preparation of methanol dispersion sol (a 1) containing hollow silica particles of aluminum

118.3G of a water-dispersible sol (a) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 15.0g of methanol was further added. The pressure was reduced to 580 Torr by a rotary evaporator, methanol was replaced while heating to 120 ℃, a methanol dispersion sol (a 1) containing hollow silica particles of aluminum was obtained. The physical properties thereof were pH3.7, an average particle diameter of 64nm as measured by the DLS method of 24.2 mass% in terms of SiO ₂, a moisture content of 0.3 mass%, a viscosity of 1.9 mPas and a surface charge amount of 59. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 2

A water-dispersible sol (a) of hollow silica particles containing aluminum was obtained by the same preparation as in example 1.

(2) Preparation of methanol dispersion sol (a 2) containing hollow silica particles of aluminum

118.3G of a water-dispersible sol (a) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 14.9g of methanol and 0.1g of Diethanolamine (DEA) were further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (a 2) containing hollow silica particles of aluminum. The physical properties thereof were pH6.3, an average particle diameter of 70nm as measured by the DLS method of 21.3 mass% in terms of SiO ₂, a moisture content of 0.3 mass%, a viscosity of 1.6 mPas and a surface charge amount of 58. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 3

(1) Preparation of Water-Dispersion Sol (b) containing hollow silica particles of aluminum

A2015 g of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato, trade name: HKT-A20-40) as a starting material was charged into a vessel, stirred, 169g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and 6g of an aqueous sodium sulfate solution (10 mass% aqueous solution in terms of Na ₂SO₄) was further added dropwise thereto, and stirred for 30 minutes.

200G of the above mixture was charged into a 300mL-SUS autoclave vessel, and subjected to heat treatment at 150℃for 5 hours, and cooled to room temperature. Next, a column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (B) of hollow silica particles containing aluminum. The physical properties were that SiO ₂ was 17.5 mass%, pH2.5, average particle diameter of 54nm by DLS method, specific surface area (C) 147m ²/g by BET method, aluminum content (A) 2400ppm bonded to the particle surface, aluminum content (B) 3200ppm existing in the whole particle, (A/B ratio) 0.75, average primary particle diameter of 49nm by TEM observation, TEM converted specific surface area (D) 56m ²/g, specific surface area ratio (C/D ratio) 2.6, refractive index of 1.31, and thickness of the shell 7.1nm.

(2) Preparation of methanol dispersion sol (b 1) containing hollow silica particles of aluminum

114.2G of a water-dispersible sol (b) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 19.2g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (b 1) containing hollow silica particles of aluminum. The physical properties thereof were pH4.9, an average particle diameter of 70nm as measured by the DLS method of 19.1 mass% in terms of SiO ₂, a moisture content of 0.3 mass%, a viscosity of 1.7 mPas and a surface charge amount of 58. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 4

A water-dispersible sol (b) of hollow silica particles containing aluminum was obtained by the same preparation as in example 3.

(2) Preparation of methanol dispersion sol (b 2) containing hollow silica particles of aluminum

114.2G of a water-dispersible sol (B) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 19.1g of methanol and 0.1g of Diethanolamine (DEA) were further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (b 2) containing hollow silica particles of aluminum. The physical properties thereof were pH8.4, an average particle diameter of 68nm as measured by the DLS method of 19.6 mass% as SiO ₂, a moisture content of 0.3 mass%, a viscosity of 1.5 mPas, and a surface charge amount of the hollow silica particles of 64. Mu. Eq/g in terms of SiO ₂ per 1g.

Example 5

(1) Preparation of Water-Dispersion Sol (c) containing hollow silica particles of aluminum

200G of the above mixture was charged into a 300mL-SUS autoclave vessel, and heat-treated at 240℃for 5 hours, and cooled to room temperature. Next, a column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (c) of hollow silica particles containing aluminum. The physical properties were that SiO ₂ was 17.8 mass%, pH2.4, average particle diameter of 54nm by DLS method, specific surface area (C) of 110m ²/g by BET method, aluminum content (A) of 1700ppm bonded to the particle surface, aluminum content (B) of 2500ppm existing in the whole particle, average primary particle diameter of 53nm by TEM observation, specific surface area (D) of 51m ²/g by TEM conversion, specific surface area ratio (C/D) of 2.1, refractive index of 1.39, and thickness of the shell of 9.5nm.

(2) Preparation of methanol dispersion sol (c 1) containing hollow silica particles of aluminum

112.7G of a water-dispersible sol (c) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 20.7g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (c 1) containing hollow silica particles of aluminum. The physical properties thereof were pH4.8, an average particle diameter of 72nm as measured by the DLS method of 21.1 mass% in terms of SiO ₂, a moisture content of 0.3 mass%, a viscosity of 1.3mPa sec, and a surface charge amount of 51. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 6

A water-dispersible sol (c) of hollow silica particles containing aluminum was obtained by the same preparation as in example 5.

(2) Preparation of methanol dispersion sol (c 2) containing hollow silica particles of aluminum

112.7G of a water-dispersible sol (c) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 20.6g of methanol and 0.1g of Diethanolamine (DEA) were further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (c 2) containing hollow silica particles of aluminum. The physical properties thereof were pH3.2, an average particle diameter of 67nm as measured by the DLS method of 21.8 mass% in terms of SiO ₂, a moisture content of 0.2 mass%, a viscosity of 1.2mPa sec, and a surface charge amount of the hollow silica particles of 43. Mu. Eq/g in terms of SiO ₂ per 1g.

Example 7

(1) Preparation of Water-Dispersion Sol (d) of hollow silica particles containing aluminum

A commercially available hollow silica aqueous sol [ Ningbo Dilato, product, (trade name) HKT-A20-40D (hollow silica aqueous sol is a substance having been subjected to a heating temperature of 100 to 240 ℃ C. In an aqueous medium), 20.0 mass% SiO ₂, pH9.3, was added to a container, an average particle diameter of 55nm as measured by the DLS method, an aluminum amount (A) bonded to the particle surface was 0.1ppm in terms of Al ₂O₃ to 1g SiO ₂ of hollow silica particles, an aluminum amount (B) present in the whole particles was 0.4ppm in terms of Al ₂O₃ to 1g SiO ₂ of hollow silica particles, an average primary particle diameter of 43nm as observed by TEM, a specific surface area ratio (A/B) was 1.8, a particle refractive index of 1.29]198g was stirred, and 169g of a diluted sodium aluminate (aqueous solution having a concentration of 1.0 mass% in terms of Al ₂O₃) was further added dropwise to an aqueous solution having a concentration of Na ₂SO₄% in terms of 10 mass% for 1 minute, and 30 minutes was stirred.

800G of the above mixture was charged into a glass-made separable flask, and the mixture was refluxed at 80℃for 5 hours, and cooled to room temperature. Next, a column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (d) of hollow silica particles containing aluminum. The physical properties were that SiO ₂ was 18.5 mass%, pH2.3, average particle diameter of 55nm by DLS method, specific surface area (C) 116m ²/g by BET method, aluminum content (A) 1100ppm bonded to the particle surface, aluminum content (B) 1400ppm existing in the whole particle, average primary particle diameter of 47nm by TEM observation, TEM converted specific surface area (D) 58m ²/g, specific surface area ratio (C/D) 2.0, refractive index of 1.27, and thickness of the shell 6.2nm.

(2) Preparation of methanol dispersion sol (d 1) containing hollow silica particles of aluminum

To a 300mL eggplant type flask, 107.9g of a water-dispersible sol (d) containing hollow silica particles of aluminum was added, and 25.5g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (d 1) containing hollow silica particles of aluminum. The physical properties thereof were pH4.9, an average particle diameter of 78nm as measured by the DLS method of 19.8 mass% in terms of SiO ₂, a moisture content of 0.2 mass%, a viscosity of 1.5 mPas and a surface charge amount of 45. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 8

A water-dispersible sol (d) of hollow silica particles containing aluminum was obtained by the same preparation as in example 7.

(2) Preparation of hollow silica methanol sol (d 2) containing aluminum

To a 300mL eggplant type flask, 107.9g of a water-dispersible sol (d) containing hollow silica particles of aluminum was added, and 25.4g of methanol and 0.1g of Diethanolamine (DEA) were further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (d 2) containing hollow silica particles of aluminum. The physical properties thereof were pH8.3, an average particle diameter of 72nm as measured by the DLS method of 21.7 mass% in terms of SiO ₂, a moisture content of 0.3 mass%, a viscosity of 1.6 mPas, and a surface charge amount of 58. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 9

(1) Preparation of hollow silica Water-dispersing Sol (e) containing aluminum

198G of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato, trade name) HKT-A20-40D as a starting material was charged into a vessel, stirred, 169g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and 6g of an aqueous sodium sulfate solution (10 mass% aqueous solution in terms of Na ₂SO₄) was further added dropwise thereto, and stirred for 30 minutes.

200G of the above mixture was charged into a 300mL-SUS autoclave vessel, and heat-treated at 150℃for 5 hours, and cooled to room temperature. Next, a column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (e) of hollow silica particles containing aluminum. The physical properties were 17.8 mass% as SiO ₂, pH2.3, average particle diameter 56nm as measured by DLS method, specific surface area (C) 115m ²/g as measured by BET method, aluminum content (A) 1500ppm as bonded to the particle surface, aluminum content (B) 2500ppm as present in the whole particle, average primary particle diameter 48nm as measured by TEM, TEM converted specific surface area (D) 57m ²/g, specific surface area ratio (C/D) 2.0, particle refractive index 1.28, and shell thickness 6.0nm.

(2) Preparation of methanol dispersion sol (e 1) containing hollow silica particles of aluminum

112.5G of a water-dispersible sol (e) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 20.8g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (e 1) containing hollow silica particles of aluminum. The physical properties thereof were pH4.6, an average particle diameter of 69nm as measured by the DLS method of 16.8 mass% as SiO ₂, a moisture content of 0.9 mass%, a viscosity of 1.3 mPas and a surface charge amount of 63. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 10

(1) Preparation of Water-Dispersion Sol (e) containing hollow silica particles of aluminum

A water-dispersible sol (e) of hollow silica particles containing aluminum was obtained by the same preparation as in example 9.

(2) Preparation of methanol dispersion sol (e 2) containing hollow silica particles of aluminum

112.5G of a water-dispersible sol (e) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 20.7g of methanol and 0.1g of Diethanolamine (DEA) were further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (e 2) containing hollow silica particles of aluminum. The physical properties thereof were pH8.2, an average particle diameter of 70nm as measured by the DLS method of 17.4 mass% in terms of SiO ₂, a moisture content of 0.3 mass%, a viscosity of 1.4 mPas, and a surface charge amount of the hollow silica particles of 64. Mu. Eq/g in terms of SiO ₂ per 1g.

Example 11

(1) Preparation of Water-Dispersion Sol (f) containing hollow silica particles of aluminum

200G of the above mixture was charged into a 300mL-SUS autoclave vessel, and heat-treated at 240℃for 5 hours, and cooled to room temperature. Next, a column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (f) of hollow silica particles containing aluminum.

The physical properties were that SiO ₂ was 18.0 mass%, pH2.5, average particle diameter of 57nm as measured by the DLS method, specific surface area (C) 116m ²/g as measured by the BET method, aluminum content (A) 1700ppm as bonded to the particle surface, aluminum content (B) 3500ppm as present in the whole particle, average primary particle diameter of 0.49 as measured by TEM, average primary particle diameter of 42nm as measured by TEM, specific surface area (D) 65m ²/g as measured by the TEM conversion, specific surface area ratio (C/D) 1.8, refractive index of 1.30 as measured by the BET method, and thickness of the shell of 6.4nm.

(2) Preparation of methanol dispersion sol (f 1) containing hollow silica particles of aluminum

110.9G of a water-dispersible sol (f) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 22.5g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (f 1) containing hollow silica particles of aluminum. The physical properties thereof were pH3.2, an average particle diameter of 70nm as measured by the DLS method of 25.6 mass% in terms of SiO ₂, a moisture content of 0.4 mass%, a viscosity of 2.2 mPas and a surface charge amount of 51. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 12

A water-dispersible sol (f) of hollow silica particles containing aluminum was obtained by the same preparation as in example 11.

(2) Preparation of methanol dispersion sol (f 2) containing hollow silica particles of aluminum

110.9G of a water-dispersible sol (f) containing hollow silica particles of aluminum was added to a 300mL eggplant-type flask, and 22.4g of methanol and 0.1g of Diethanolamine (DEA) were further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (f 2) containing hollow silica particles of aluminum. The physical properties thereof were pH3.6, an average particle diameter of 70nm as measured by the DLS method of 16.9 mass% as SiO ₂, a moisture content of 0.6 mass%, a viscosity of 1.2 mPas and a surface charge amount of 61. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 13

(1) Preparation of methanol dispersion sol (d 2) containing hollow silica particles of aluminum

A methanol dispersion sol (d 2) containing hollow silica particles of aluminum was obtained by the same method as in example 8.

(2) Preparation of Methyl Ethyl Ketone (MEK) dispersion sol (d 3) containing hollow silica particles of aluminum treated with silane

35.35G of the hollow silica particle-containing methanol dispersion sol (d 2) prepared in example 8 was put into a 300mL eggplant-type flask, 10.93g of methanol and 0.38g of water were added thereto and stirred, and 0.34g of 3- (methacryloyloxy) propyltrimethoxysilane (product name KBM-503 manufactured by Xinyue chemical Co., ltd.) was further added thereto, and the mixture was refluxed at 72℃for 5 hours while stirring. Then, the mixture was cooled to room temperature, reduced in pressure to 250 torr by a rotary evaporator, and MEK substitution was performed in a state where the mixture was heated at 75 ℃, thereby obtaining a MEK-dispersed sol (d 3) obtained by silane-treating aluminum-containing hollow silica particles. The physical properties thereof were pH6.0, an average particle diameter of 77nm as measured by the DLS method of 14.9 mass% in terms of SiO ₂, a moisture content of 0.1 mass%, a viscosity of 6.3mPa sec, and a surface charge amount of 51. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 14

(1) Preparation of methanol dispersion sol (e 2) containing hollow silica particles of aluminum

A methanol dispersion sol (e 2) containing hollow silica particles of aluminum was prepared in the same manner as in example 10.

(2) Preparation of Methyl Ethyl Ketone (MEK) dispersion sol (e 3) containing hollow silica particles of aluminum treated with silane

35.71G of the hollow silica particles containing aluminum prepared in example 10 was put into a 300mL eggplant type flask, 4.29g of methanol and 0.09g of water were added thereto and stirred, and 0.28g of 3- (methacryloyloxy) propyltrimethoxysilane (product name KBM-503, manufactured by Xinyue chemical Co., ltd.) was further added thereto, and the mixture was refluxed at 72℃for 5 hours while stirring. Then, the mixture was cooled to room temperature, reduced in pressure to 250 torr by a rotary evaporator, and MEK substitution was performed in a state of being heated to 75 ℃, to obtain a MEK-dispersed sol (e 3) in which hollow silica particles containing aluminum were silane-treated. The physical properties thereof were pH5.8, an average particle diameter of 88nm as measured by the DLS method of 12.4 mass% in terms of SiO ₂, a moisture content of 0.2 mass%, a viscosity of 6.3 mPas and a surface charge amount of 60. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 15

(1) Preparation of hollow silica Water-dispersing Sol (g) containing aluminum

2500.0G of a commercially available hollow silica aqueous sol (product name: HKT-A20-40D, manufactured by Ningbo Dilato Co., ltd.) as a starting material was charged into a vessel, stirred, 42.5g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and stirred for 60 minutes.

The above mixture 2537.6g was charged into a 3L-SUS autoclave vessel, subjected to heat treatment at 150℃for 5 hours, and cooled to room temperature. Further, 6.1g of 8% sulfuric acid was added thereto with stirring, and the mixture was stirred for 1 hour, followed by passing a liquid through the column-packed cation exchange resin (H-type Latin IR-120B) at a Space Velocity (SV) of 5/hour, to obtain an aqueous sol A having a pH of 2.4 and a mass% of 18.9 in terms of SiO ₂.

The aqueous sol A was subjected to a heating treatment at 80℃for 10 hours, cooled to room temperature for 8 hours, and then passed through a column-packed cation exchange resin (type H-type IR-120B) at a Space Velocity (SV) of 5/hour to obtain an aqueous dispersion sol (g) of hollow silica particles containing aluminum. The physical properties were 17.0 mass% as SiO ₂, pH2.3, average particle diameter of 54nm as measured by DLS method, specific surface area (C) of 116m ²/g as measured by BET method, aluminum content (A) of 1500ppm as bonded to the particle surface, aluminum content (B) of 2500ppm as present in the whole particle, average primary particle diameter of 0.60 as measured by TEM, average primary particle diameter of 43nm as measured by TEM, specific surface area (D) of 63m ²/g as measured by TEM, specific surface area ratio (C/D) of 1.8, refractive index of 1.27, and thickness of 6.0nm of the shell.

(2) Preparation of methanol dispersion sol (g 1) containing hollow silica particles of aluminum

To a 2L eggplant type flask was added 690.4g of a water-dispersible sol (g) of hollow silica particles containing aluminum, and 68.1g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (g 1) containing hollow silica particles of aluminum. The physical properties thereof were that pH3.3, an average particle diameter of 73nm as measured by the DLS method was 27.4 mass% in terms of SiO ₂, moisture content was 0.5 mass%, viscosity was 1.6 mPas, and the surface charge amount of the hollow silica particles was 38. Mu. Eq/g in terms of SiO ₂ per 1g. The physical properties of the mixture, which was adjusted to 20.5 mass% based on SiO ₂, were pH3.5, water content 0.5 mass%, and viscosity 1.2 mPas.

(3) Preparation of Methyl Ethyl Ketone (MEK) dispersion sol (g 1) in silane-treated hollow silica particles containing aluminum

123.8G (20.5 mass% based on SiO ₂) of a methanol dispersion sol (g 1) containing hollow silica particles of aluminum was charged into a 500mL eggplant-type flask, 44.3g of methanol and 1.3g of water were added and stirred, and 1.27g of 3- (methacryloyloxy) propyltrimethoxysilane (product name KBM-503, manufactured by Xinyue chemical Co., ltd.) was further added, and the mixture was refluxed at 72℃for 5 hours while stirring. Then, the mixture was cooled to room temperature, reduced in pressure to 400 torr by a rotary evaporator, and MEK substitution was performed in a state of being heated to 75 ℃, to obtain a MEK-dispersed sol (g 1) in which hollow silica particles containing aluminum were silane-treated. The physical properties thereof were pH3.8, an average particle diameter of 66nm as measured by the DLS method of 22.3 mass% in terms of SiO ₂, and moisture content of 0.02 mass%, and a surface charge amount of the hollow silica particles of 43. Mu. Eq/g in terms of SiO ₂ per 1 g. The physical properties of the mixture after the addition of MEK to the mixture was adjusted to 20.5 mass% based on SiO ₂ were pH3.8, water content 0.02 mass%, and viscosity 1.5mPa sec.

Example 16

(1) Preparation of methanol dispersion sol (i 1) containing hollow silica particles of aluminum

The same procedure as in example 15 was carried out except that the aqueous sol A was heated at 80℃for 10 hours and cooled to room temperature over 1 hour. Specifically, a commercially available hollow silica aqueous sol (product name: HKT-a20-40D, manufactured by Ningbo Dilato) was used as a starting material, and the hollow silica aqueous sol containing aluminum was further solvent-substituted with methanol by a method in which an aqueous sodium sulfate solution was not added at the time of doping with aluminum atoms of the aqueous sodium aluminate solution, to obtain a methanol dispersion sol (i 1) containing hollow silica particles containing aluminum. The physical properties thereof were pH3.5, an average particle diameter of 72nm as measured by the DLS method of 23.5 mass% in terms of SiO ₂, moisture of 0.4 mass%, viscosity of 1.3mPa sec, and a surface charge amount of 52. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles. The physical properties of the substance adjusted to 20.5 mass% based on SiO ₂, which was added with methanol, were pH3.6, water content 0.3 mass%, and viscosity 1.2mPa sec.

(2) Preparation of a methanol dispersion sol (i 2) in which hollow silica particles containing aluminum are treated with silane

151.2G (20.5 mass% based on SiO ₂) of a methanol dispersion sol (i 1) containing hollow silica particles of aluminum was put into a 500mL eggplant type flask, 45.9g of methanol and 1.55g of water were added and stirred, and 1.35g of 3- (acryloyloxy) propyltrimethoxysilane (AcPS, trade name KBM-5103, manufactured by Xinyue chemical Co., ltd.) was further added, and the mixture was refluxed at 72℃for 5 hours while stirring. Then, the mixture was cooled to room temperature to prepare a silane-treated hollow silica particle-containing methanol dispersion sol (i 2). The physical properties thereof were that pH3.7, average particle diameter 72nm as measured by the DLS method was 15.6 mass% in terms of SiO ₂, water content 1.0 mass%, viscosity 1.1 mPas, and surface charge amount 56. Mu. Eq/g in terms of SiO ₂ per 1g of hollow silica particles.

Example 17

(1) Preparation of methanol dispersion sol (j 1) containing hollow silica particles of aluminum

The same procedure as in example 15 was carried out except that the aqueous sol A was heated at 80℃for 10 hours and cooled to room temperature over 2.5 hours. Specifically, a commercially available hollow silica aqueous sol (product name: HKT-a20-40D, manufactured by Ningbo Dilato) was used as a starting material, and the hollow silica aqueous sol containing aluminum was further solvent-substituted with methanol by a method in which an aqueous sodium sulfate solution was not added at the time of doping with aluminum atoms of the aqueous sodium aluminate solution, to obtain a methanol dispersion sol (j 1) containing hollow silica particles containing aluminum. The physical properties thereof were pH3.4, an average particle diameter of 69nm as measured by the DLS method of 20.5 mass% as SiO ₂, a moisture content of 0.6 mass%, a viscosity of 1.2 mPas and a surface charge amount of 47. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

(2) Preparation of silane-treated hollow silica particles containing aluminum in methanol Dispersion sol (j 2)

151.2G (20.5 mass% based on SiO ₂) of a methanol dispersion sol (j 1) containing hollow silica particles of aluminum was put into a 500mL eggplant-type flask, 46.3g of methanol and 1.09g of water were added and stirred, and 1.43g of 3- (methacryloyloxy) propyltrimethoxysilane (product name KBM-503, manufactured by Xinyue chemical Co., ltd.) was further added and the mixture was refluxed at 72℃for 5 hours while stirring. Then, the mixture was cooled to room temperature to prepare a silane-treated hollow silica particle-containing methanol dispersion sol (j 2). The physical properties were pH3.6, and the average particle diameter of the polymer particles measured by the DLS method was 70nm, 16.3 mass% as SiO ₂, and 1.0 mass% as water.

Example 18

(1) Preparation of hollow silica Water-dispersing Sol (k) containing aluminum

200G of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato, trade name) as a starting material, HKT-A20-40D, was charged into a vessel, stirred, 40.0g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and 0.59g of an aqueous sodium sulfate solution (10 mass% aqueous solution in terms of Na ₂SO₄) was further added dropwise thereto, and the mixture was stirred for 30 minutes.

240G of the above mixture was charged into a 300mL-SUS autoclave vessel, and heat-treated at 150℃for 5 hours, and cooled to room temperature. Next, the column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (k) of hollow silica particles containing aluminum. The physical properties were 16.9 mass% as SiO ₂, pH2.6, an average particle diameter of 56nm as measured by the DLS method, a specific surface area (C) of 115m ²/g as measured by the BET method, an aluminum content (B) of 4500ppm as a whole of the particles, an average primary particle diameter of 48nm as measured by TEM, a TEM-converted specific surface area (D) of 57m ²/g, a specific surface area ratio (C/D ratio) of 2.0, a particle refractive index of 1.28, and a thickness of 6.0nm of the shell.

(2) Preparation of methanol dispersion sol (k 1) containing hollow silica particles of aluminum

118.3G of a water-dispersible sol (k) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 10.7g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (k 1) containing hollow silica particles of aluminum. The physical properties of the hollow silica particles were pH3.5, average particle diameter of 72nm as measured by the DLS method, moisture content of 0.5 mass%, and surface charge amount of the hollow silica particles per 1g of SiO ₂ was 46. Mu. Eq/g.

Example 19

(1) Preparation of hollow silica Water-dispersing Sol (m) containing aluminum

200G of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato, trade name) HKT-A20-40D as a starting material was charged into a vessel, stirred, 80.0g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and 0.59g of sodium sulfate aqueous solution (10 mass% aqueous solution in terms of Na ₂SO₄) was further added dropwise thereto, and stirred for 30 minutes.

240G of the above mixture was charged into a 300mL-SUS autoclave vessel, and heat-treated at 150℃for 5 hours, and cooled to room temperature. Next, the column-packed cation exchange resin (type H) was passed through the column at a Space Velocity (SV) of 5/hour to obtain a water-dispersible sol (m) of hollow silica particles containing aluminum.

The physical properties were 13.8 mass% as SiO ₂, pH2.8, average particle diameter 68nm as measured by DLS method, specific surface area (C) 115m ²/g as measured by BET method, aluminum content (B) 6200ppm as the whole particle, average primary particle diameter 48nm as measured by TEM, TEM converted specific surface area (D) 57m ²/g, specific surface area ratio (C/D ratio) 2.0, particle refractive index 1.28, and shell thickness 6.0nm.

(2) Preparation of methanol dispersion sol (m 1) containing hollow silica particles of aluminum

144.9G of a water-dispersible sol (m) containing hollow silica particles of aluminum was added to a 300mL eggplant type flask, and 5.0g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (m 1) containing hollow silica particles of aluminum. The physical properties of the hollow silica particles were pH3.7, average particle diameter of 82nm as measured by the DLS method, water content of 0.5 mass%, and surface charge amount of the hollow silica particles per 1g of SiO ₂ was 59. Mu. Eq/g.

Example 20

(1) Preparation of hollow silica Water-dispersing Sol (n) containing aluminum

As a starting material, 2500.1g of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato Co., ltd., (trade name) HKT-A20-40D, 20.8 mass% in terms of SiO ₂) was charged into a vessel, stirred, 44.2g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise over 1 minute, and stirred for 60 minutes.

The above mixture 2487.5g was charged into a 3L-SUS autoclave vessel, heat-treated at 150℃for 5 hours, and cooled to room temperature to obtain a water-dispersible sol (n) of hollow silica particles containing aluminum. The physical properties thereof were 20.1 mass% as SiO ₂, pH10.1, an average particle diameter of 51nm as measured by the DLS method, a specific surface area (C) of 126m ²/g as measured by the BET method, an average primary particle diameter of 45nm as measured by TEM, a specific surface area (D) of 61m ²/g as measured by TEM, a specific surface area ratio (C/D ratio) of 2.1, a particle refractive index of 1.26, and a thickness of 5.0nm.

(2) Preparation of methanol dispersion sol (n 1) containing hollow silica particles of aluminum

To a 300mL eggplant type flask, 74.2g of a water-dispersible sol (n) containing hollow silica particles of aluminum was added, and 21.9g of methanol was further added. The pressure was reduced to 580 torr by a rotary evaporator, and methanol substitution was performed in a state of being heated to 120 ℃, thereby obtaining a methanol dispersion sol (n 1) containing hollow silica particles of aluminum. The physical properties thereof were pH5.6, an average particle diameter of 77nm as measured by the DLS method of 20.5 mass% in terms of SiO ₂, a moisture content of 0.7 mass%, a viscosity of 1.6 mPas and a surface charge amount of 38. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 21

(1) Preparation of hollow silica Water-dispersing Sol (p) containing aluminum

The same procedure as in example 15 was carried out. That is, a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato, trade name) HKT-A20-40D was used as a starting material, and a water-dispersible sol (p) of hollow silica particles containing aluminum was obtained by a method in which an aqueous sodium sulfate solution was not added at the time of doping of aluminum atoms with an aqueous sodium aluminate solution. The physical properties thereof were 17.7 mass% as SiO ₂, pH2.3, an average particle diameter of 54nm as measured by the DLS method, a specific surface area (C) of 116m ²/g as measured by the BET method, an average primary particle diameter of 43nm as measured by TEM, a TEM-converted specific surface area (D) of 63m ²/g, a specific surface area ratio (C/D ratio) of 1.8, a particle refractive index of 1.27, and a thickness of 6.0nm.

(2) Preparation of Propylene Glycol Monomethyl Ether (PGME) dispersion sol (p 3) containing hollow silica particles of aluminum

To a 2L eggplant type flask, 712.0g of a water-dispersible sol (p) containing hollow silica particles of aluminum was added, and 99.0g of PGME was further added. PGME substitution was performed by a rotary evaporator under reduced pressure to 70 torr and in a state of being heated at 70 ℃, to obtain a PGME dispersion sol (p 3) of hollow silica particles containing aluminum. The physical properties thereof were pH3.7, an average particle diameter of 73nm as measured by the DLS method of 21.2 mass% in terms of SiO ₂, a moisture content of 0.1 mass%, a viscosity of 4.0 mPas, and a surface charge amount of 37. Mu. Eq/g in terms of SiO ₂ per 1g of the hollow silica particles.

Example 22

(1) Preparation of methanol dispersion sol (q 1) containing hollow silica particles of aluminum

The same procedure as in example 15 was carried out except that the aqueous sol A was heated at 80℃for 10 hours and cooled to room temperature over 4 hours. Specifically, a commercially available hollow silica aqueous sol (product name: HKT-a20-40D, manufactured by Ningbo Dilato) was used as a starting material, and the hollow silica aqueous sol containing aluminum was further solvent-substituted with methanol by a method in which an aqueous sodium sulfate solution was not added at the time of doping with aluminum atoms of the aqueous sodium aluminate solution, to obtain a methanol dispersion sol (q 1) containing hollow silica particles containing aluminum. The physical properties thereof were pH3.4, an average particle diameter of 69nm as measured by the DLS method of 21.5 mass% as SiO ₂, a moisture content of 0.2 mass%, a viscosity of 1.2mPa sec, and a surface charge amount of the hollow silica particles of 40. Mu. Eq/g in terms of SiO ₂ per 1 g.

(2) Preparation of silane-treated aluminum-containing hollow silica particles Propylene Glycol Monomethyl Ether Acetate (PGMEA) dispersion sol (q 4)

50.00G (20.5 mass% based on SiO ₂) of a methanol dispersion sol (q 1) containing hollow silica particles of aluminum was charged into a 300mL eggplant type flask, 18.35g of methanol and 0.54g of water were added thereto and stirred, and 0.39 of 3-mercaptopropyltrimethoxysilane (trade name KBM-803, manufactured by Xinyue chemical Co., ltd.) was further added thereto, and the mixture was refluxed at 72℃for 5 hours while stirring. Then, the mixture was cooled to room temperature, reduced to 80 torr by a rotary evaporator, and PGMEA substitution was performed in a state of being heated to 75 ℃, to obtain a PGMEA dispersion sol (q 4) in which hollow silica particles containing aluminum were silane-treated. The physical properties thereof were that the average particle diameter measured by the DLS method was 84nm, 15.9 mass% as SiO ₂, 0.2 mass% as moisture, and the surface charge amount of the hollow silica particles was 38. Mu. Eq/g as calculated per 1g of SiO ₂, and 0.7 mass% as MeOH.

Example 23

(1) Preparation of methanol dispersion sol (r 1) containing hollow silica particles of aluminum

The same procedure as in example 15 was carried out except that the aqueous sol A was heated at 80℃for 10 hours and cooled to room temperature over 4 hours. Specifically, a commercially available hollow silica aqueous sol (product name: HKT-a20-40D, manufactured by Ningbo Dilato) was used as a starting material, and the hollow silica aqueous sol containing aluminum was further solvent-substituted with methanol by a method in which an aqueous sodium sulfate solution was not added at the time of doping with aluminum atoms of the aqueous sodium aluminate solution, to obtain a methanol dispersion sol (r 1) containing hollow silica particles containing aluminum. The physical properties thereof were pH3.4, an average particle diameter of 69nm as measured by the DLS method of 21.5 mass% as SiO ₂, a moisture content of 0.2 mass%, a viscosity of 1.2mPa sec, and a surface charge amount of the hollow silica particles of 40. Mu. Eq/g in terms of SiO ₂ per 1 g.

(2) Preparation of silane-treated aluminum-containing hollow silica particles Propylene Glycol Monomethyl Ether Acetate (PGMEA) dispersion sol (r 5)

To a 300mL eggplant-type flask was added 49.92g (20.5 mass% based on SiO ₂) of a methanol dispersion sol (r 1) containing hollow silica particles of aluminum, 18.44g of methanol and 0.54g of water were added and stirred, and further 0.64 of hexamethyldisiloxane (HMDSO, trade name KF-96L-0.65CS, manufactured by Xinyue chemical Co., ltd.) was added and the mixture was refluxed at 60℃for 2 hours while stirring. Then, the mixture was cooled to room temperature, depressurized to 400 Torr by a rotary evaporator, and then treated with PGMEA 40g while heating to 75℃until the distillate was 34g. 0.64g of HMDSO was added thereto, and the mixture was refluxed at 60℃for 2 hours with stirring. Then, the mixture was cooled to room temperature, the pressure was reduced to 80 torr by a rotary evaporator, and the mixture was treated with PGMEA 20g while heating to 75 ℃ until the distillate was 26g, to obtain a PGMEA dispersion sol (r 5) of silane-treated hollow silica particles containing aluminum. The physical properties thereof were that pH4.0, average particle diameter of 77nm measured by the DLS method was 16.9 mass% as SiO ₂, water content was 0.1 mass%, and the surface charge amount of the hollow silica particles was 34. Mu. Eq/g as calculated per 1g of SiO ₂, meOH was 0.2 mass%.

Example 24

(1) Preparation of hollow silica Water-dispersing Sol(s) containing aluminum

2500.0G of a commercially available hollow silica aqueous sol (product name: HKT-A20-40D, manufactured by Ningbo Dilato Co., ltd.) as a starting material was charged into a vessel, stirred, 5.0g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and stirred for 60 minutes.

2500.0G of the above mixture was charged into a 3L-SUS autoclave vessel, heat-treated at 150℃for 5 hours, and cooled to room temperature to obtain a stable alkaline hollow silica water-dispersion sol(s) containing aluminum. The amount of aluminum (A) bonded to the particle surface was 100ppm.

Comparative example 1

A2015 g of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato, trade name) of HKT-A20-40 as a starting material was charged into a vessel, stirred, 169g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and 6g of an aqueous sodium sulfate solution (10 mass% aqueous solution in terms of Na ₂SO₄) was further added dropwise thereto, and stirred at room temperature (20 ℃) for 30 minutes.

The gel was gelled in the column by passing a liquid through the column-packed cation exchange resin (H-type) at a Space Velocity (SV) of 5/hr without heat treatment, and thus the desired water-dispersible sol of hollow silica particles containing aluminum was not obtained.

Comparative example 2

198G of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato, trade name) HKT-A20-40D as a starting material was charged into a vessel, stirred, 169g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, and 6g of an aqueous sodium sulfate solution (10 mass% aqueous solution in terms of Na ₂SO₄) was further added dropwise thereto, and the mixture was stirred at room temperature (20 ℃ C.) for 30 minutes.

Comparative example 3

(1) Preparation of hollow silica Water-dispersing Sol (l) containing aluminum

2500.0G of a commercially available hollow silica aqueous sol (manufactured by Ningbo Dilato Co., ltd. (trade name) HKT-A20-40D) as a starting material was charged into a vessel, stirred, and 2.5g of diluted sodium aluminate (1.0 mass% aqueous solution in terms of Al ₂O₃) was added dropwise thereto over 1 minute, followed by stirring for 60 minutes.

2500.0G of the above mixture was charged into a 3L-SUS autoclave vessel, heat-treated at 150℃for 5 hours, and cooled to room temperature. The amount of aluminum (A) bonded to the particle surface was 50ppm. Further, while stirring, 6.1g of 8% sulfuric acid was added thereto, and the mixture was stirred for 1 hour, and the mixture was passed through a column-packed cation exchange resin (H-type Latretin IR-120B) at a Space Velocity (SV) of 5/hour, whereby the column was closed in the middle, and an aqueous sol was not obtained.

Industrial applicability

It is possible to provide hollow silica particles having aluminum atoms bonded to the surfaces of the hollow silica particles in a specific ratio in terms of Al ₂O₃, and a hollow silica sol for mixing the hollow silica particles with an organic solvent and a resin with good compatibility.

Claims

1. A hollow silica particle having a space in the interior of a shell, wherein the hollow silica particle contains an aluminum atom forming an aluminosilicate site, and wherein the aluminum atom is bonded to the surface of the hollow silica particle in a ratio (A) of 100 to 20000ppm/SiO ₂ to 1g SiO ₂ in terms of Al ₂O₃ conversion in the measurement by the leaching method.

2. The hollow silica particles according to claim 1, wherein the leaching method is a method in which the hollow silica particles are leached with an aqueous solution of at least 1 inorganic acid selected from sulfuric acid, nitric acid and hydrochloric acid, and the ratio (a) of 1g SiO ₂ to the hollow silica particles is calculated in terms of Al ₂O₃ of a compound containing aluminum atoms bonded to the surfaces of the hollow silica particles.

3. The hollow silica particles according to claim 1 or 2, wherein in the measurement by the dissolution method using an aqueous hydrofluoric acid solution, aluminum atoms present in the whole hollow silica particles are bonded in a ratio (B) of 120 to 50000ppm/SiO ₂ to 1g SiO ₂ in terms of Al ₂O₃ conversion, and the value obtained by dividing the ratio (a) by the ratio (B) is 0.001 to 1.0.

4. The hollow silica particles according to any one of claims 1 to 3, wherein the ratio of [ the specific surface area (C) of the hollow silica particles as measured by the BET method, i.e., the nitrogen adsorption method ]/[ the specific surface area (D) of the hollow silica particles as measured by a transmission electron microscope ] is 1.40 to 5.00.

5. The hollow silica particle according to any one of claims 1 to 4, wherein the hollow silica particle has a surface charge amount of 5 to 250. Mu. Eq/g in terms of SiO ₂ per 1g.

6. The hollow silica particle according to any one of claims 1 to 5, further coated with at least 1 silane compound selected from the group consisting of formula (1), formula (2) and formula (3),

R ¹ _aSi(R²)_4-a (1)

[ R ³ _bSi(R⁴)_3-b〕₂Y_c (2)

R ⁵ _dSi(R⁶)_4-d (3)

In the formula (1), R ¹ is each an alkyl group, a haloalkyl group, an alkenyl group, an aryl group, or an organic group having an epoxy group, a (meth) acryloyl group, a mercapto group, a amino group, a ureido group, or a cyano group and bonded to a silicon atom through a Si-C bond, R ² is each an alkoxy group, an acyloxy group, or a halogen atom, a is an integer of 1 to 3,

In the formula (2) and the formula (3), R ³ and R ⁵ are each an alkyl group having 1to 3 carbon atoms or an aryl group having 6 to 30 carbon atoms and bonded to a silicon atom by a si—c bond, R ⁴ and R ⁶ are each an alkoxy group, an acyloxy group or a halogen atom, Y is an alkylene group, an NH group or an oxygen atom, b is an integer of 1to 3, C is an integer of 0 or 1, and d is an integer of 1to 3.

7. A hollow silica sol comprising the hollow silica particles according to any one of claims 1 to 6 dispersed in a dispersion medium, wherein the hollow silica particles have an average particle diameter of 20 to 150nm as measured by a dynamic light scattering method.

8. The hollow silica organosol according to claim 7, wherein the dispersion medium is an alcohol having 1 to 10 carbon atoms, a ketone having 1 to 10 carbon atoms, an ether having 1 to 10 carbon atoms, or an ester having 1 to 10 carbon atoms.

9. The hollow silica sol of claim 7 or 8, further comprising an amine.

10. The hollow silica sol according to claim 9, wherein the amine is at least 1 amine selected from the group consisting of primary amines having 1 to 10 carbon atoms, secondary amines having 1 to 10 carbon atoms, and tertiary amines having 1 to 10 carbon atoms.

11. The hollow silica sol according to claim 9 or 10, wherein the amine is a water-soluble amine having a water solubility of 80g/L or more.

12. The hollow silica sol according to any one of claims 9 to 11, wherein the amine content is 0.001 to 10 mass% relative to SiO ₂ of the hollow silica particles.

13. A composition for forming a coating film, comprising the hollow silica particles according to any one of claims 1 to 6, and an organic resin.

14. The composition for forming a coating film according to claim 13, wherein the hollow silica particles are derived from the hollow silica sol according to any one of claims 7 to 12.

15. A film obtained from the composition for forming a coating film according to claim 13 or 14, and having a visible light transmittance of 80% or more.

16. The method for producing a hollow silica sol according to any one of claims 7 to 12, comprising the following steps (I) and (II):

(II) procedure: and (3) adding an aluminum compound to the hollow silica aqueous sol obtained in the step (I) in an amount of 0.0001 to 0.5g per 1g of hollow silica particles in terms of Al ₂O₃, and heating the mixture at 40 to 260 ℃ for 0.1 to 48 hours.

17. The method for producing a hollow silica sol according to claim 16, wherein the hollow silica aqueous sol used in the step (I) is subjected to a step of heating at a heating temperature of less than 100 ℃ in an aqueous medium.

18. The method for producing a hollow silica sol according to claim 16, wherein the hollow silica aqueous sol used in the step (I) is subjected to a step of heating at a heating temperature of 100 to 240 ℃ in an aqueous medium.

19. The method according to any one of claims 16 to 18, wherein the aluminum compound used in the step (II) is at least 1 aluminum compound selected from the group consisting of aluminates, aluminum alkoxides, and hydrolysates thereof, and the step (II) uses an aqueous solution containing the same.

20. The method for producing a hollow silica sol according to any one of claims 16 to 19, wherein the step (II) comprises the steps of: and (II-i) adding an amine.

21. The method for producing a hollow silica sol according to any one of claims 16 to 19, wherein the step (II) comprises the steps of: and (II-II) adding a neutral salt composed of a combination of at least 1 cation selected from sodium ions, potassium ions and ammonium ions and an inorganic anion or an organic anion to the hollow silica particles in an amount of 0.1 to 10 mass% relative to SiO ₂.

22. The method for producing a hollow silica sol according to claim 21, wherein the inorganic anion used in the step (II-II) is a sulfate ion, a chloride ion or a phosphate ion, and the organic anion is a carboxylate ion, a hydroxycarboxylic acid ion or an amino acid.

23. The method for producing a hollow silica sol according to any one of claims 16 to 22, wherein the step (II) comprises the steps of:

A step of adding the aluminum compound, or the aluminum compound and at least 1 additive selected from the group consisting of an amine and a neutral salt, to a hollow silica aqueous sol and heating the same; and

A subsequent step of contacting the cation exchange resin with (II-iii), a step of adding an acid (II-iv), or a combination thereof.

24. The method for producing a hollow silica sol according to any one of claims 16 to 23, further comprising, after the step (II), the steps of: and (III) a step of replacing the aqueous medium in the hollow silica sol with a C1-10 alcohol, a C1-10 ketone, a C1-10 ether, or a C1-10 ester.

25. The method for producing a hollow silica sol according to claim 24, further comprising, after the step (III), the steps of: and (IV) adding and heating at least 1 silane compound selected from the group consisting of the above-mentioned formulas (1), (2) and (3).

26. The method according to claim 24 or 25, wherein the step (III) and the step (IV) are performed by adding at least 1 silane compound selected from the group consisting of the above-mentioned formulas (1), (2) and (3) to the aqueous medium of the hollow silica sol after the step (III) is performed by replacing the solvent with an alcohol having 1 to 10 carbon atoms, the aqueous medium of the hollow silica sol is heated, and the aqueous medium is further replaced with a ketone having 1 to 10 carbon atoms, an ether having 1 to 10 carbon atoms, or an ester having 1 to 10 carbon atoms.

27. A method for adjusting the surface charge of hollow silica particles using the production method according to any one of claims 16 to 26.