JP2014094865A - Method of producing silica particle having internal cavity, silica particle having internal cavity and coating liquid for film formation and film-provided substrate containing the silica particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silica particle which is useful as e.g. a low-refractive-index material, a low-dielectric-constant material, a heat insulation material, an adsorbent, a separation material and a sustained release material and has a cavity inside a polygonal shape having a relatively large particle size and its production method.SOLUTION: A method of producing a silica particle having an internal cavity includes: a step (a) of adding an aqueous solution of a silicate and/or an acidic silicate solution and an aqueous solution of an alkali-soluble inorganic compound other than silica simultaneously to a zeolite particle fluid dispersion in such a manner as to form a complex oxide (hydrate) layer of silica and the inorganic compound on the surface of the zeolite particles having a weight ratio (W)/(W) of the amount (W), by solid contents, of zeolite particles and the amount (W), by solid contents, of the complex oxide (hydrate) layer formed on the surface of the zeolite particles in a range of 0.1 to 5.0 in order to prepare a zeolite-complex oxide particle fluid dispersion; and a step (b) of adding an acid to the zeolite-complex oxide particle fluid dispersion to remove at least a part of the elements constituting the zeolite-complex oxide particles other than silicon.

Description

  The present invention relates to a method for producing silica particles having a cavity inside and a silica particle having a cavity inside.

Conventionally, hollow silica particles having a particle size of about 0.1 to 300 μm are known (see Patent Document 1, Patent Document 2, etc.). Also, there is a method for producing hollow particles made of a dense silica shell by precipitating active silica from an alkali metal silicate aqueous solution on a core made of a material other than silica and removing the material without destroying the silica shell. It is publicly known (see Patent Document 3).
Furthermore, micron-sized spherical silica particles having a core-shell structure in which the outer peripheral portion is a shell and the central portion is hollow, the outer shell is denser on the outer side, and has a coarser concentration gradient structure on the inner side are known (Patent Document 4, etc.) reference).

In addition, the applicant of the present application previously proposed that nanometer-sized composite oxide particles having a low refractive index can be obtained by completely covering the surface of porous inorganic oxide particles with silica or the like ( Furthermore, a silica coating layer is formed on the core particles of a composite oxide composed of silica and an inorganic oxide other than silica, and then the inorganic oxide other than silica is removed, and silica is coated as necessary. By doing so, it has been proposed that nanometer-sized silica-based fine particles with a low refractive index having cavities inside can be obtained (see Patent Document 6).
Furthermore, by preparing a composite oxide composed of silica and an inorganic oxide other than silica in the presence of an electrolyte, and then removing the inorganic oxide other than silica, a nanometer-sized low refractive index having a cavity inside It has been proposed that silica-based fine particles can be obtained (see Patent Document 7).

  Here, in the methods disclosed in Patent Documents 6 and 7, nanometer-sized silica-based fine particles can be prepared in a relatively short time, but it takes a long time to prepare submicron-sized silica-based particles. In short, there was room for improvement in terms of economy.

Further, it is disclosed that hollow silica nanoparticles can be obtained by preparing calcium carbonate particles, coating silica on the particles, and then dissolving calcium carbonate. At this time, it is described that the silica nanoparticles have pores (see Patent Document 8).
Further, it is described that cubic silica (polyhedral structure) hollow silica particles can be obtained by the same method (see Patent Document 9).

However, the silica particles described in Patent Document 8 and Patent Document 9 are secondary particles in which primary particles are aggregated and have pores, and therefore, when used as an antireflection coating material, Depending on the type of the binder component, the antireflection performance may be insufficient, and the adhesion to the base material, the strength of the coating film, the transparency, and the like may be insufficient.

JP-A-6-330606 Japanese Patent Laid-Open No. 7-013137 Special Table 2000-500113 JP-A-11-029318 JP 7-133105 A JP 2001-233611 A JP 2004-203683 A JP 2005-263550 A JP 2007-305884 A

As a result of diligent investigations to prepare hollow silica particles having a polyhedral shape, the present inventors simultaneously added a water glass aqueous solution and a sodium aluminate aqueous solution to a zeolite particle dispersion to form a silica alumina layer on the surface of the zeolite particles. Then, by dissolving and removing the alumina component with hydrochloric acid, silica particles having a polyhedral shape and having cavities inside are obtained, and it is found that these particles are non-aggregated (monodispersed, primary particles) particles. It came to complete.
An object of this invention is to provide the silica particle which has a polyhedron shape, and has a cavity inside, and its manufacturing method.

The method for producing silica particles having cavities inside according to the present invention is characterized by comprising the following steps (a) and (b).
(A) An amount of silicate aqueous solution and / or acidic silicic acid solution and an aqueous solution of an inorganic compound other than alkali-soluble silica as a solid content of zeolite particles (W _Z ), and the zeolite particle surface The weight ratio (W _M ) / (W _Z ) with the amount (W _M ) as the solid content of the composite oxide (hydrate) layer formed in the range of 0.1 to 5.0 A step of simultaneously adding and forming a composite oxide (hydrate) layer of silica and inorganic oxide on the surface of the zeolite particles to prepare a zeolite / composite oxide particle dispersion (b) the zeolite / composite oxide; A step of adding an acid to the particle dispersion to remove at least a part of elements other than silicon constituting the zeolite / composite oxide particles.

The molar ratio MO _X / SiO ₂ when the aqueous solution of silicate and / or the silica of the acidic silicate solution in the step (a) is represented by SiO ₂ and the inorganic oxide other than silica is represented by MO _X is 0.01 to It is preferable to be in the range of 0.18.
Following the step (b), the following step (c) is preferably performed.
(C) Step of aging at 50 to 350 ° C. The pH in the step (a) is preferably in the range of 8 to 14.
The zeolite is preferably a crystalline aluminosilicate, and the SiO ₂ / Al ₂ O ₃ molar ratio of the zeolite is preferably in the range of 2-20.

The first aspect of the zeolite preferably has a dice structure, and the average particle diameter (P _Z ) of the zeolite is preferably in the range of 0.03 to 50 μm.
The second aspect of the zeolite has a flat plate structure, the average thickness (T _Z ) of the zeolite is in the range of 0.01 to 10 μm, the average particle diameter (P _Z ) and the average thickness ( T _Z) and the ratio of _{(P Z) / (T Z} ) is preferably in the range of 2-20.

The first aspect of the silica particles having a cavity inside according to the present invention is a silica particle having a hollow inside of the outer shell, the silica particle has a dice-like structure, and the average particle diameter of the silica particle It is characterized in that (P _S ) is in the range of 0.04 to 55 μm.
A second aspect of the silica particle having a cavity inside according to the present invention is a silica particle having a hollow inside of the outer shell, the silica particle has a plate-like structure, and the average thickness of the silica particle ( T _S ) is in the range of 0.02 to 11 μm, and the ratio (P _S ) / (T _S ) of the average particle diameter (P _S ) to the average thickness (T _S ) of the silica particles is in the range of 2 to 20. It is characterized by that.

The outer shell is preferably non-porous.
The refractive index measured by the standard refractive index liquid method is preferably in the range of 1.10 to 1.44.
The outer shell is preferably porous.
The refractive index measured by the standard refractive index liquid method is preferably in the range of 1.40 to 1.46.
It is preferable that the void ratio of the inside of the outer shell is in the range of 5 to 90% by volume.
It is preferable that the silica particle which has a cavity inside is the silica particle obtained by the manufacturing method of the silica particle which has a cavity inside in any one of Claims 1-7.

The coating liquid for forming a film according to the present invention comprises silica particles having cavities therein, a matrix-forming component, and a dispersion medium, and the concentration (C _S ) of the silica particles having cavities therein is 0 as a solid content. 0.005 to 48% by weight, the concentration (C _M ) of the matrix-forming component is in the range of 0.2 to 59.7% by weight as the solid content, and the total solid content concentration is 1 to 60% by weight. It is characterized by being in range.
The silica particles having cavities in the interior are preferably silica particles having cavities in the interior according to claim 15.
The silica particles having cavities in the interior have a plate-like structure, the average thickness (T _S ) of the silica particles is in the range of 0.02 to 0.15 μm, and the average particle diameter (P _S ) is 0.04. It is preferable that the ratio (P _S ) / (T _S ) between the average particle diameter (P _S ) and the average thickness (T _S ) is in the range of 2-20.

The substrate with a coating according to the present invention comprises a substrate and a coating formed on the substrate, and the coating contains silica particles having a cavity inside and a matrix component, and is formed in the coating. The content (W _S ) of the silica particles having cavities is in the range of 0.5 to 80% by weight as the solid content, and the content (W _M ) of the matrix component is in the range of 20 to 99.5% by weight. It is characterized by.
The silica particles having cavities in the interior are preferably silica particles having cavities in the interior according to claim 15.
The silica particles having cavities in the interior have a plate-like structure, the average thickness (T _S ) of the silica particles is in the range of 0.02 to 0.15 μm, and the average particle diameter (P _S ) is 0.04. It is preferable that the ratio (P _S ) / (T _S ) between the average particle diameter (P _S ) and the average thickness (T _S ) is in the range of 2-20.

According to the present invention, a silica particle having a cavity inside a polyhedral shape having a relatively large particle diameter, which is useful as a low refractive index material, a low dielectric constant material, a heat insulating material, an adsorbent, a separating material, a sustained release agent, etc. And a manufacturing method thereof.

Hereinafter, first, a method for producing silica particles having a cavity inside according to the present invention will be described.
Sequentially illustrating a manufacturing method of silica particles having a cavity therein in accordance with the production method the present invention silica particles having voids therein from step (a).

Step (a)
A silicate aqueous solution and / or an acidic silicate solution and an aqueous solution of an inorganic compound other than alkali-soluble silica in the zeolite particle dispersion are formed on the zeolite particle surface in an amount (W _Z ) as a solid content of the zeolite particles. Simultaneously added so that the weight ratio (W _M ) / (W _Z ) to the amount (W _M ) as the solid content of the composite oxide (hydrate) layer is in the range of 0.1 to 5.0. A composite oxide (hydrate) layer of silica and inorganic oxide is formed on the surface of the zeolite particles to prepare a zeolite / composite oxide particle dispersion.

Zeolite As the zeolite used in the present invention, zeolite which is crystalline aluminosilicate is used. For example, forgerite (FAU), chabasite (CHA), beta (BEA), ZSM-5 (MFI), A-type zeolite (LTA), mordenite (MOR) and the like can be mentioned.
Such zeolite has two-dimensional or three-dimensional pores, and the skeleton is made of silica and alumina, but the shape, size, and void ratio required for the resulting silica particles with voids inside. , And can be appropriately selected depending on the refractive index and the like.
For example, faujasite (FAU) having a relatively high alumina content and a large pore volume can be suitably used to obtain silica particles having a high porosity.

The SiO ₂ / Al ₂ O ₃ molar ratio of zeolite is preferably in the range of 2 to 15, more preferably 2 to 11.
There is no zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of less than 2 in the zeolite, and when the SiO ₂ / Al ₂ O ₃ molar ratio exceeds 11, removal of Al ₂ O ₃ with an acid becomes difficult and obtained. In some cases, the porosity of the silica particles is too small, and a sufficient effect cannot be obtained even when used for a low refractive index material, a heat insulating material or the like.

Most of the zeolite particles have a dice-like particle shape, and the average particle diameter (P _Z ) of the zeolite used is preferably in the range of 0.03 to 50 μm, more preferably 0.1 to 20 μm.
It is difficult to obtain a zeolite having an average particle diameter (P _Z ) of less than 0.03 μm, and it is difficult to obtain a zeolite having an average particle diameter (P _Z ) exceeding 50 μm. In the method, it is difficult to obtain silica particles having a high porosity.
Zeolite can be used as it is, but it can also be refined to a desired particle size by pulverization or the like, if necessary.

In the present invention, zeolite particles having a plate-like structure can also be suitably used.
When zeolite particles having a flat structure are used, the resulting silica particles having cavities also have a flat structure, and such flat silica particles can be densely laminated to form a film. It can be suitably used as a low reflective material, a heat insulating material, a separating material, a sustained release agent, a low dielectric constant agent, and the like.
The zeolite particles having a flat structure used at this time preferably have an average thickness (T _Z ) in the range of 0.01 to 10 μm, and more preferably in the range of 0.03 to 5.0 μm.
It is difficult to obtain one having an average thickness (T _Z ) outside the above range.
In this case as well, the zeolite can be used as it is, but if necessary, it can be used after being refined to a desired particle diameter by pulverization or the like.

Further, the ratio (P _Z ) / (T _Z ) (sometimes referred to as aspect ratio) of the average particle diameter (P _Z ) to the average thickness (T _Z ) is in the range of 2 to 20, more preferably 3 to 10. Preferably there is.
When (P _Z ) / (T _Z ) is less than 2, the silica particles obtained are not different from the zeolite particles having the above-mentioned dice-like structure, and those having (P _Z ) / (T _Z ) exceeding 20 can be obtained. Is difficult.
As such zeolite particles having a flat plate structure, the zeolites disclosed in Japanese Patent Application Laid-Open Nos. 2008-230886 and 2004-315338, which are filed by the present applicant, can be suitably used.

In the present invention, the average particle diameter (P _Z ) and the average thickness (T _Z ) are obtained by taking a scanning electron micrograph (SEM), and in the case of a zeolite particle having a dice structure, the particle diameter is measured for 100 particles. In the case of flat zeolite, the particle diameter and thickness were measured for 100 particles, and the average value was obtained. In the above, the particle diameter was determined by measuring the long diameter of the particle and the short diameter of the particle, and taking the average value thereof.
The same applies to silica particles having cavities inside as described later.

As the silicate aqueous solution and acidic silicate liquid silicate, one or more silicates selected from alkali metal silicates, ammonium silicates and silicates of organic bases are preferably used. Examples of the alkali metal silicate include sodium silicate (water glass) and potassium silicate, and examples of the organic base include quaternary ammonium salts such as tetraethylammonium salt, amines such as monoethanolamine, diethanolamine, and triethanolamine. The ammonium silicate or organic base silicate includes an alkaline solution in which ammonia, quaternary ammonium hydroxide, an amine compound, or the like is added to the silicic acid solution.
As the acidic silicic acid solution, a silicic acid solution obtained by removing an alkali by treating an alkali silicate aqueous solution with a cation exchange resin or the like can be used. In particular, pH _{2 to} pH 4 and SiO ₂ concentration is about 7% by weight. The following acidic silicic acid solutions are preferred.

Inorganic compounds other than alkali-soluble silica Examples of the alkali-soluble inorganic compound include alkali metal salts or alkaline earth metal salts, ammonium salts, and quaternary ammonium salts of metal or non-metal oxo acids. More specifically, sodium aluminate, sodium tetraborate, zirconyl ammonium carbonate, potassium antimonate, potassium stannate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, sodium phosphate and the like can be mentioned.

In the step (a), the silicate aqueous solution and / or the acidic silicate liquid and the inorganic compound aqueous solution other than the alkali-soluble silica are simultaneously added to the zeolite particle dispersion.
At this time, the concentration of the zeolite particle dispersion is preferably in the range of 0.001 to 20.0% by weight, more preferably 0.03 to 5.0% by weight.
If the concentration of the zeolite dispersion is less than 0.001% by weight, a composite oxide (hydrate) layer of silica and inorganic oxide may not be efficiently formed on the surface of the zeolite particles. In some cases, silica particles that form particles and have cavities inside that have a desired low refractive index, heat insulation, and the like cannot be obtained.
When the concentration of the zeolite dispersion exceeds 20% by weight, the zeolite particles forming the composite oxide (hydrate) layer become aggregated particles, and finally the silica particles having cavities inside become aggregated particles, limiting the application. May be.

The addition ratio of the silicate aqueous solution and / or the acidic silicate solution and the aqueous inorganic compound solution other than silica is the molar ratio MO _X / SiO ₂ when the silica component is represented by SiO ₂ and the inorganic compound other than silica is represented by MO _X. Is preferably in the range of 0.01 to 0.18, more preferably 0.1 to 0.15.
When the molar ratio MO _X / SiO ₂ is less than 0.01, it is difficult to remove the MO _X component with an acid, the inner zeolite cannot be dissolved, and cavities may not be formed.

When the molar ratio MO _X / SiO ₂ exceeds 0.18, the dissolution and desorption of the SiO ₂ component become significant along with the desorption of the MO _X component of the outer complex oxide (hydroxide) layer, Silica particles having cavities may not be obtained.
If the molar ratio MO _X / SiO ₂ is in the above range, the Al ₂ O ₃ component inside the zeolite particles can be removed while leaving the silica layer in the outer shell, and the silica particles having cavities inside can be removed. Can be obtained.

The amount of the aqueous solution of the silicate and / or the aqueous solution of the inorganic compound other than the acidic silicate solution and silica is the amount (W _Z ) as the solid content of the zeolite particles and the complex oxide (hydration) formed on the surface of the zeolite particles. The weight ratio (W _M ) / (W _Z ) to the amount (W _M ) as the solid content of the product) layer is in the range of 0.1 to 5.0, more preferably 0.25 to 3.0. It is preferable to do.
When the (W _M ) / (W _Z ) is less than 0.1, it varies depending on the particle diameter of the zeolite particles used, but the outer shell layer is too thin to maintain a hollow shape, Silica particles having cavities may not be obtained.
When the (W _M ) / (W _Z ) exceeds 5.0, the outer shell layer becomes too thick, and it becomes difficult to remove the Al ₂ O ₃ component inside the zeolite particles, and there is a cavity inside the desired interior. Silica particles may not be obtained.

The pH of the zeolite particle dispersion when forming the composite oxide (hydrate) layer is preferably in the range of 8 to 14, more preferably 10 to 13.
If the pH of the zeolite particle dispersion is in the above range, a desired composite oxide (hydrate) layer can be formed while maintaining the shape and size of the zeolite.
Further, the temperature of the zeolite particle dispersion when forming the composite oxide (hydrate) layer is generally 30 to 100 ° C, preferably 50 to 98 ° C.

Step (b)
An acid is added to the zeolite particle dispersion formed with the composite oxide (hydrate) layer to remove at least a part of elements other than silicon constituting the zeolite / composite oxide (hydrate) layer.
The concentration of the zeolite particle dispersion in which the complex oxide (hydrate) layer is formed varies depending on the treatment temperature, but is 0.1 to 50% by weight, particularly 0.5 to 25% by weight as a solid content. Is preferred.
When the concentration of the zeolite particle dispersion having the composite oxide (hydrate) layer is less than 0.1% by weight, the amount of silica dissolved is large and the treatment efficiency is lowered. Also, if the concentration of the zeolite particle dispersion in which the composite oxide (hydrate) layer is formed exceeds 50% by weight, the dispersibility of the particles becomes insufficient, and the composite oxide fine particles having a high content of elements other than silicon However, it may not be able to be removed uniformly or efficiently with a small number of times.

As the acid, mineral acids such as hydrochloric acid, nitric acid and sulfuric acid are preferable, but organic acids or a mixture with organic acids can also be used. In addition, an H-type ion exchange resin can be used in place of the acid.
For removal of elements other than silicon, the resulting silica particles having cavities in the silica are represented by SiO ₂ , and the remaining oxides of elements other than silicon are represented by MO _X , the molar ratio MO _X / SiO _2. Is preferably 0.0001 to 0.2, more preferably 0.0001 to 0.1.

When the molar ratio MO _X / SiO ₂ is less than 0.0001, it is difficult to obtain, and when it exceeds 0.2, it means that removal of elements other than silicon is insufficient, and the desired refractive index And properties such as heat insulation may not be obtained.
The temperature of the dispersion when removing at least a part of elements other than silicon is preferably in the range of approximately 5 to 50 ° C.

In this invention, it is preferable to wash | clean after the said process (b).
The washing method is not particularly limited as long as the dissolved component and the electrolyte component can be removed, but a filtration separation method can be adopted when the particle size of the silica particles is relatively large, and ultrafiltration when the particle size is small, It can be washed by a known washing method such as an ion exchange resin method.
The degree of washing varies depending on the application, but it is preferable that the amount of components other than SiO ₂ which is the main component of silica particles and Al ₂ O ₃ remaining due to the raw material zeolite is small.
Thus, the silica particle which has a cavity inside according to the present invention can be obtained.

  The silica particles having cavities inside obtained at this stage are porous silica particles whose outer shells have fine pores. The porous silica particles are useful silica fine particles such as an adsorbent, a separating material, a sustained release agent and the like. The porous silica particles can also be used as a low refractive index material, a heat insulating material, or the like by using a material that closes the pores.

Step (c)
Then, it can be aged at 50 to 350 ° C, more preferably 80 to 250 ° C.
By aging in such a temperature range, the fine pores are closed, and silica particles useful as a low refractive index material, a heat insulating material and the like can be obtained.
When the aging temperature is less than 50 ° C., although it varies depending on the aging time, clogging of fine holes in the outer shell becomes insufficient, and the usefulness as a low refractive index material and a heat insulating material may be insufficient.
When the aging temperature exceeds 350 ° C., aggregated silica particles may be formed, and the use may be limited.
Furthermore, after aging, it can be washed in the same manner as described above. By washing after aging, silica particles with few impurities and excellent dispersion stability can be obtained.

Moreover, in the above, the silica layer of the outer shell of the silica particles after the step (b) and the silica layer of the outer shell of the silica particles when the aging temperature in the step (c) is low are porous, When the temperature in the step (c) is high, the silica layer of the outer shell of the silica particles tends to be nonporous.
Here, the term “porous” and “nonporous” refers to the average particle diameter (P _S ) of the above-described polyhedral and flat silica particles having cavities inside, and the silica particles are regarded as spherical particles. The surface specific surface area (S _CAL ) is calculated, and the case where the specific surface area (S _M ) separately measured by the BET method has the following relationship is defined as porous.
2 × (S _CAL ) ≦ (S _M )

At this time, in the step (c), the temperature at which the porous material and the nonporous material are separated is not necessarily constant, and the type and composition of the raw material zeolite, the composition of the composite oxide (hydration layer), the amount formed, and the step ( It also depends on the conditions for removing elements other than silicon in b) and the pH at the time of treatment.
The silica particles thus obtained preferably have cavities inside the outer shell silica layer, and the void ratio is preferably in the range of 5 to 90% by volume, more preferably 20 to 90% by volume.

Also, silica particles having a cavity therein which is obtained in this way, when the zeolite particles to be used have a polyhedral shape mentioned above, the obtained silica particles also have a polyhedral shape, average particle size (P _S ) Is in the range of 0.04 to 55 μm, preferably 0.12 to 25 μm.
Moreover, when the zeolite particle to be used is a flat plate as described above, the obtained silica particles are also flat and the average thickness (T _S ) of the silica particles is in the range of 0.02 to 11 μm, preferably 0.03 to 5 μm. is there. Further, the ratio (P _S ) / (T _S ) between the average particle size (P _S ) and the average thickness (T _S ) is in the range of 2 to 20, preferably 3 to 10.

Next, silica particles having a cavity inside according to the present invention will be described.
Silica particles having a cavity inside The first aspect of the silica particles having a cavity inside according to the present invention is a silica particle having a hollow inside the outer shell, the silica particle having a dice-like structure, the average particle diameter of the silica particles _{(P S)} is being in the range of 0.04～55Myuemu.
Here, the dice-like structure means a shape having a basic shape of a polyhedron such as a cube (dice-like), a quadrangular column, a hexagonal column, and an octahedron, excluding a flat plate structure to be described later.

  Whether or not the inside is a cavity can be confirmed by crushing silica particles and observing with a transmission electron micrograph based on the presence or absence of a space where silica is not present. Alternatively, in the case of silica particles whose outer shell, which will be described later, is nonporous, the refractive index can be measured by a standard refractive index liquid method and confirmed by being lower than the refractive index of silica (1.46).

The average particle diameter (P _S ) of such silica particles having cavities therein is preferably in the range of 0.04 to 55 μm, more preferably 0.05 to 25 μm.
When the average particle diameter (P _S ) of silica particles having cavities is out of the above range, it is difficult to obtain zeolite particles as a raw material, and even if obtained, the method of the present invention has a high porosity. It is difficult to obtain silica particles.
Zeolite can be used as it is, but it can also be refined to a desired particle size by pulverization or the like, if necessary.

A second aspect of the silica particle having a cavity inside according to the present invention is a silica particle having a hollow inside of the outer shell, the silica particle has a plate-like structure, and the average thickness of the silica particle ( T _S ) is in the range of 0.02 to 11 μm, and the ratio (P _S ) / (T _S ) of the average particle diameter (P _S ) to the average thickness (T _S ) of the silica particles is in the range of 2 to 20. It is preferable that it exists in.
The average thickness (T _S ) is preferably in the range of 0.02 to 11 μm, more preferably 0.03 to 5 μm.
When the average thickness (T _S ) is out of the above range, it is difficult to obtain zeolite particles as a raw material, and even if obtained, it may be difficult to obtain silica particles having voids by the method of the present invention. is there.
The ratio (P _S ) / (T _S ) between the average particle diameter (P _S ) and the average thickness (T _S ) is preferably in the range of 2 to 20, more preferably 3 to 10.

  When such flat silica particles are used, they can be densely laminated to form a film, which can be suitably used as a film-like low-reflecting material, heat insulating material, separating material, and the like. In particular, a coated substrate having excellent scratch resistance can be obtained.

The flat silica particles having cavities inside when used as a coated substrate have an average thickness (T _S ) of the silica particles in the range of 0.02 to 0.15 μm, more preferably 0.03 to 0.12 μm. The average particle size (P _S ) is preferably in the range of 0.04 to 1 μm, more preferably 0.05 to 0.3 μm.
Further, the ratio (P _S ) / (T _S ) between the average particle diameter (P _S ) and the average thickness (T _S ) is preferably in the range of 2 to 20, more preferably 3 to 10.
If the ratio (P _S ) / (T _S ) of the average thickness (T _S ) and the average particle diameter (P _S ) to the average thickness (T _S ) is within the above range, the layers are densely laminated to form a film. Thus, a coated substrate with excellent scratch resistance, transparency and excellent antireflection performance can be obtained.

The silica particles in which the inside of the outer shell is hollow may be non-porous or porous.
Silica particles having a non-porous outer shell preferably have a refractive index measured by a standard refractive index liquid method of 1.10 to 1.44, more preferably 1.10 to 1.39.
The silica particles having a porous outer shell have a refractive index measured by a standard refractive index liquid method in a range of approximately 1.40 to 1.46.
Silica particles having a non-porous outer shell can be suitably used as a low reflection material, a heat insulating material, a low dielectric constant material, etc., and silica particles having a porous outer shell can be used as an adsorbent, a desiccant, a separating material, a sustained release material. It can be suitably used as an agent or the like.

The silica particles preferably have a void ratio of 5 to 90% by volume, more preferably 15 to 80% surrounded by a cavity inside the outer shell.
When the porosity is less than 5% by volume, a sufficient effect may not be obtained when used as a low reflective material, a heat insulating material, a low dielectric constant material or the like, and a product with a porosity exceeding 90% by volume is obtained. Even if it is obtained, the strength of the particles may be sufficient, and there are restrictions on the use and usage.
Here, the void ratio was calculated by measuring the refractive index as follows and calculating by the following formula.
Void ratio (%) = (1.46-measured refractive index) / (0.46 × 100) (%)
However, 1.46 is the refractive index of silica, and 0.46 is the refractive index difference between silica and air.

Measurement of Refractive Index (1) The silica particle dispersion is taken in an evaporator and the dispersion medium is evaporated.
(2) This is dried at 120 ° C. to obtain a powder.
(3) A standard refracting liquid having a known refractive index is dropped on a glass plate of a few drops, and the powder is mixed therewith.
(4) The operation of (3) is performed with various standard refractive liquids, and the refractive index of the standard refractive liquid when the mixed liquid becomes transparent is the refractive index of the silica particles.
The silica particles having cavities in the interior are preferably silica particles having cavities in the interior obtained by the method for producing silica particles according to the present invention.

Next, the coating liquid for forming a film according to the present invention will be described.
Coating Film-Forming Coating Liquid The coating film-forming coating liquid according to the present invention comprises silica particles having cavities therein, a matrix-forming component, and a dispersion medium, and the concentration of silica particles having cavities therein (C _S ). Is in the range of 0.005 to 48% by weight as the solid content, the concentration (C _M ) of the matrix-forming component is in the range of 0.2 to 59.7% by weight as the solid content, and the total solid content concentration is 1 It is characterized by being in the range of ˜60% by weight.

As the silica particles having cavities inside the silica particles having cavities inside, the silica particles having cavities inside are preferably used.
In the present invention, it is preferable to use silica particles having cavities inside having a flat structure.
At this time, it is preferable that the average thickness (T _S ) of the silica particles having a flat structure and having cavities therein is in the range of 0.02 to 0.15 μm, more preferably 0.03 to 0.12 μm.
When the average thickness (T _S ) is within the above range, it is possible to form a film having excellent adhesion to the substrate and excellent scratch resistance and transparency.

The average particle diameter (P _S ) is preferably in the range of 0.04 to 1 μm, more preferably 0.05 to 0.3 μm.
When the average particle diameter (P _S ) is within the above range, a film having excellent adhesion to the substrate and excellent scratch resistance, transparency, and antireflection performance can be formed.
The ratio (P _S ) / (T _S ) of the average particle diameter (P _S ) and the average thickness (T _S ) is in the range of 2 to 20, preferably 3 to 10.

  Moreover, when using for the coating liquid for film formation, it can be used after surface-treating as needed. As the surface treatment method, a conventionally known silane coupling agent, surfactant or resin can be used.

Matrix-forming component As the matrix-forming component, a conventionally known matrix-forming component can be used. For example, a sol-gel matrix-forming component that is a hydrolyzate of an organosilicon compound, or an organic resin-based matrix-forming component is used. be able to.
As the organic resin matrix forming component, specifically, any of thermosetting resins, thermoplastic resins, ultraviolet curable resins and the like known as coating resins can be employed. For example, conventionally used polyester resins, polycarbonate resins, polyamide resins, polyphenylene oxide resins, thermoplastic acrylic resins, vinyl chloride resins, fluororesins, vinyl acetate resins, silicone rubber and other thermoplastic resins, urethane resins, melamine resins And thermosetting resins such as silicon resin, butyral resin, reactive silicone resin, phenol resin, epoxy resin, unsaturated polyester resin, and acrylic resin. Further, it may be a copolymer or modified body of two or more of these resins.
These resins may be emulsion resins, water-soluble resins, and hydrophilic resins.

Dispersion medium The dispersion medium used in the present invention is not particularly limited as long as it can dissolve or disperse the silica particles and the matrix-forming component, and a conventionally known solvent can be used.
For example, alcohols such as methanol, ethanol, propanol, 2-propanol (IPA), butanol, diacetone alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, isopropyl glycol; acetic acid methyl ester, ethyl acetate Esters such as esters and butyl acetate; diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol isopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, pull Ethers such as pyrene glycol monoethyl ether; Emissions, methyl ethyl ketone, methyl isobutyl ketone, butyl methyl ketone, cyclohexanone, methyl cyclohexanone, dipropyl ketone, methyl pentyl ketone, diisobutyl ketone, isophorone, acetylacetone, ketones such as acetoacetate, toluene, xylene and the like. These may be used alone or in combination of two or more.

The concentration (C _S ) of the silica particles having cavities in the coating liquid for forming a film is preferably in the range of 0.005 to 48% by weight, more preferably 0.01 to 42% by weight as the solid content.
If the concentration (C _S ) of the silica particles having cavities in the coating liquid for forming a film is within the above range, the coating liquid has good stability, excellent coating properties, adhesion, transparency, and scratch resistance. A film having excellent properties can be formed.

The concentration (C _M ) of the matrix-forming component is preferably in the range of 0.2 to 59.7% by weight, more preferably 0.3 to 59.4% by weight as the solid content.
When the concentration (C _M ) of the matrix-forming component is in the above range, the coating solution is also excellent in stability, excellent in coatability, and can form a film excellent in adhesion, transparency, and scratch resistance. it can.
The total solid concentration of the coating liquid for forming a film is preferably in the range of 1 to 60% by weight, more preferably 2 to 50% by weight.

Next, the coated substrate according to the present invention will be described.
The coated substrate according to the present invention comprises a substrate and a coating formed on the substrate, the coating comprising silica particles having a cavity inside and a matrix component, The content (W _S ) of silica particles having cavities therein is in the range of 0.5 to 80% by weight as the solid content, and the content (W _M ) of the matrix component is 20 to 99.5% by weight. It is characterized by being in range.

As the silica particles having cavities inside the silica particles having cavities inside, the silica particles having cavities inside are preferably used.
In the present invention, it is preferable to use silica particles having cavities inside having the above-described flat structure.

As the matrix component , a conventionally known matrix component can be used, and a cured product of the matrix forming component used in the coating liquid for film formation described above is used.
The content (W _S ) of silica particles having cavities inside the coating is preferably in the range of 0.5 to 80% by weight, more preferably 1 to 70% by weight, as the solid content.
When the content (W _S ) of silica particles having cavities in the coating is in the above range, a coating excellent in adhesion, transparency, scratch resistance, and antireflection performance can be formed.

The content of matrix components in the coating _{(W M)} is 20 to 99.5% by weight solids, more preferably in the range of 30 to 99 wt%. .
When the content (W _M ) of the matrix component in the coating is in the above range, a coating excellent in adhesion, transparency and scratch resistance can be formed.

The following examples further illustrate the present invention.
[Example 1]
Synthesis of NaY-type zeolite (1)
Preparation of Seed Solution (1) A sodium hydroxide aqueous solution (Al ₂ O ₃ : 22 wt%, Na ₂ O: 17 wt%) was stirred in 187.0 g of a 37.2 wt% sodium hydroxide aqueous solution in 57.0 g. Then, 755.6 g of No. 3 sodium silicate aqueous solution having a SiO ₂ concentration of 17.5 wt% was slowly added. At this time, the temperature was maintained at 20 ° C.
Next, after stirring for 1 hour, the mixture was allowed to stand at 20 ° C. for 16 hours, and this solution was aged at 20 ° C. for 600 hours to obtain a seed solution (1).

Preparation of matrix hydrogel slurry 40.4 g of silica sol (JGC Catalysts & Chemicals Co., Ltd .: Cataloid SI-550) having an average particle size of 5 nm and SiO ₂ concentration of 20% by weight diluted with 2864.0 g of pure water was heated to 80 ° C. Then, 3635.9 g of No. 3 water glass having a SiO ₂ concentration of 1.8 wt% and 6692.5 g of an aqueous sodium aluminate solution having an Al ₂ O ₃ concentration of 0.4 wt% were simultaneously added over 4 hours. Further, 111.0 g of a 3% by weight aqueous sodium hydroxide solution was added over 1 hour.

Next, while stirring 9000 g of the matrix hydrogel slurry, 1000 g of the seed solution (1) was added and mixed at room temperature for 30 minutes. Thereafter, hydrothermal treatment was performed at 95 ° C. for 48 hours, followed by washing to synthesize NaY-type zeolite (1).
The NaY-type zeolite (1) was subjected to shape characteristic measurement and composition analysis (SiO ₂ / Al ₂ O ₃ ), and the results are shown in the table.
Regarding the shape characteristics, a scanning electron micrograph (SEM) was taken, the shape of 50 particles was observed, the thickness (Tz) and the particle diameter (Pz) were measured, and the average value was obtained.

Preparation of silica particles (1) After adding 3900 g of pure water to 100 g of NaY-type zeolite (1), adjust the pH to 12.0 by adding NaOH aqueous solution with a concentration of 10 wt. Meanwhile, 190 g of a sodium silicate aqueous solution having a concentration of 3.0% by weight as SiO2 and 60g of a sodium aluminate solution having a concentration of 1.0% by weight as Al2O3 were added in one hour, and a composite of silica and alumina was added to the surface of the zeolite particles. A zeolite / composite oxide particle dispersion in which an oxide layer was formed was prepared. At this time, (W _M ) / (W _Z ) was 1.6, and the pH of the dispersion was 11.8. [Step (a)]

Next, after washing with an ultrafiltration membrane to a solid content concentration of 13% by weight, filtration through a capsule filter having an opening of 1 μm, a zeolite / composite oxide particle (1) dispersion having a solid content concentration of 13% by weight is obtained. It was.
To 500 g of the zeolite / composite oxide particle (1) dispersion, 1,125 g of pure water was added, and concentrated hydrochloric acid (concentration 35.5 wt%) was added dropwise to adjust the pH to 1.0, followed by dealumination. Next, 10 mL of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water are added, and the dissolved / desorbed aluminum is separated by an ultrafiltration membrane method and washed to prepare a silica particle (1 _b ) dispersion with a solid content concentration of 20% by weight. did. [Step (b)]

Next, aqueous ammonia is added to the silica particle (1 _b ) dispersion to adjust the pH of the dispersion to 12.0, and after aging at 200 ° C. for 3 hours, the mixture is cooled to room temperature, and cation exchange resin is obtained. (Mitsubishi Chemical Corporation: Diaion SK1B) ion exchange for 3 hours using 400 g, then ion exchange resin (Mitsubishi Chemical Corporation: Diaion SA20A) 200 g ion exchange for 3 hours, Further, 200 g of cation exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B) was used for ion exchange at 80 ° C. for 3 hours for washing, and a silica particle (1 _c ) dispersion with a solid content concentration of 20% by weight was washed. Obtained. [Step (c)]

Then, the silica particle (1 _c ) dispersion was dried to obtain silica particles (1).
With respect to the obtained silica particles (1), shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity) were measured, and the results are shown in the table.
Regarding the shape characteristics, a scanning electron micrograph (SEM) was taken, the shape of 50 particles was observed, the thickness (Ts) and the particle diameter (Ps) were measured, and the average value was obtained.

[Example 2]
Synthesis of NaY-type zeolite (2) In Example 1, NaY-type zeolite (2) was synthesized in the same manner except that 4500 g of matrix hydrogel slurry was used and 2000 g of seed solution was used.
The NaY-type zeolite (2) was subjected to shape characteristic measurement and composition analysis, and the results are shown in the table.

Preparation of silica particles (2) Silica particles (2) were obtained in the same manner as in Example 1, except that 100 g of NaY zeolite (2) was used.
The obtained silica particles (2) were measured for shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity), and the results are shown in the table.

Preparation of paint for forming transparent film (2) An ethanol dispersion of silica particles (2) having a solid content concentration of 5% by weight was prepared. 60 g of this dispersion and acrylic resin (Hitaroid 1007, manufactured by Hitachi Chemical Co., Ltd.) 2 0.5 g and 37.5 g of a 1/1 (weight ratio) mixed solvent of isopropanol and n-butanol were sufficiently mixed to prepare a coating material (2) for forming a transparent film having a solid content concentration of 5.5% by weight.

Preparation of coating liquid for hard coat film formation (2) Silica sol dispersion (manufactured by JGC Catalysts &Chemicals; Cataloid SI-30; average particle size 12 nm, SiO ₂ concentration 40.5 wt%, dispersion medium: isopropanol, particle refractive index 1.46) 100 g .gamma.-methacryloxypropyltrimethoxysilane trimethoxysilane 1.88 g (Shin-Etsu silicone - emissions Co.: KBM-503, SiO ₂ component 81.2%) were mixed ultrapure water 3.1 g of the mixture was added and stirred at 50 ° C. for 20 hours to obtain a surface-treated 12 nm silica sol dispersion (solid content concentration: 40.5 wt%).
Thereafter, the solvent was replaced with propylene glycol monopropyl ether (PGME) by a rotary evaporator (solid content: 40.5%).

  Subsequently, 51.85 g of a propylene glycol monopropyl ether dispersion of silica sol having a solid content concentration of 40.5% by weight, 18.90 g of dihexaerythritol triacetate (manufactured by Kyoeisha Chemical Co., Ltd .: DPE-6A), 1.6- 2.10 g of hexanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd .; Light Acrylate SR-238F), 0.01 g of a silicone leveling agent (manufactured by Enomoto Kasei Co., Ltd .; Disparon 1610), and a photopolymerization initiator (Ciba Japan) Co., Ltd .: Irgacure 184, dissolved in PGME to a solid content concentration of 10%) 12.60 g and PGME 14.54 g were mixed well to form a hard coat film-forming coating with a solid content concentration of 42.0% by weight. Liquid (2) was prepared.

Manufacture of substrate (2) with transparent coating for antireflection A coating liquid (2) for forming a hard coat film was prepared by using a TAC film (manufactured by Panac Corporation: FT-PB80UL-M, thickness: 80 μm, refractive index: 1. 51) was coated by the bar coater method (# 14), dried at 80 ° C. for 120 seconds, and then cured by irradiating with 300 mJ / cm ² of ultraviolet rays to form a hard coat film. The film thickness of the hard coat film was 5 μm.
Next, a coating solution (2) for forming an antireflection transparent coating was applied by the bar coater method (bar # 4), dried at 80 ° C. for 120 seconds, and then irradiated with 600 mJ / cm ² of ultraviolet light in an N ₂ atmosphere. And cured to produce a substrate (2) with a transparent coating for antireflection. At this time, the film thickness of the antireflection transparent coating was 100 nm.

The substrate (2) with a transparent coating for antireflection was measured for total light transmittance, haze, reflectance of light having a wavelength of 550 nm, coating refractive index, adhesion, pencil hardness, and scratch resistance.
The total light transmittance and haze were measured with a haze meter (manufactured by Suga Test Instruments Co., Ltd.), and the reflectance was measured with a spectrophotometer (JASCO Corporation, Ubest-55). Further, the refractive index of the film was measured with an ellipsometer (EMS-1, manufactured by ULVAC). The haze was 0.1%, the total light transmittance was 93%, the reflectance was 0.6%, and the refractive index of the film. The rate was 1.38. The uncoated PET film had a total light transmittance of 90.7%, a haze of 2.0%, and a reflectance of light having a wavelength of 550 nm of 6.0%.

Pencil hardness Pencil hardness was measured with a pencil hardness tester in accordance with JIS K 5400. That is, a pencil was set at an angle of 45 degrees with respect to the transparent coating surface, and a predetermined load was applied and pulled at a constant speed, and the presence or absence of scratches was observed.
When a 4H pencil was used, no scratch was generated, but when a 5H pencil was used, a scratch was generated.

The surface of the substrate with adhesive transparent coating is made of 11 parallel scratches with a knife at intervals of 1 mm in length and width to make 100 squares, cellophane tape is adhered to this, and then the cellophane tape is peeled off when the cellophane tape is peeled off. The adhesion was evaluated by classifying the number of cells remaining without peeling into the following three stages. The result was ◎.
More than 90 remaining squares: ◎
Number of remaining squares: 85 to 89: ○
Number of remaining squares: 84 or less: △

Measurement of scratch resistance Using # 0000 steel wool, sliding 50 times with a load of 500 g / cm ² , visually observing the surface of the film, and evaluating according to the following criteria. The result was ◎.
No streak injury is observed: ◎
Slight streak scars: ○
Many streak wounds are found:
The surface has been scraped as a whole: ×

  The flat silica particles having cavities in the present invention are excellent in transparency, low in reflectance, excellent in pencil hardness, adhesion and scratch resistance, as compared with Comparative Example 5 described later.

[Example 3]
Synthesis of NaY-type zeolite (3) In Example 1, NaY-type zeolite (3) was synthesized in the same manner except that 250 g of the seed solution (1) was used.
The NaY zeolite (3) was subjected to shape characteristic measurement and composition analysis, and the results are shown in the table.

Preparation of silica particles (3) In Example 1, silica particles (3) were obtained in the same manner except that 100 g of NaY-type zeolite (3) was used.
The obtained silica particles (3) were measured for shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity), and the results are shown in the table.

[Example 4]
Preparation of seed solution (4) 200 g of water was mixed with 849 g of a water glass solution (SiO ₂ concentration: 24 wt%), and 388 g of sodium hydroxide with a concentration of 48 wt% was mixed with this to prepare a solution A.
Separately, 284 g of water was mixed with 107 g of an aqueous sodium aluminate solution (Al ₂ O ₃ concentration: 22% by weight) to prepare solution B.
Next, liquid A and liquid B were mixed and stirred for 1 hour, and then allowed to stand at 30 ° C. for 10 hours to prepare a seed solution (4).
The composition of this time is _{15.9Na 2 O · Al 2 O 3} · 14.7SiO 2 · 330H 2 O in oxide molar ratio.

825 g of silica fine powder is dispersed in 325 g of synthetic water of NaY-type zeolite (4), 975 g of a water glass solution (SiO ₂ concentration: 24% by weight) is mixed with this, and then the seed solution (4) 130. 5 g was added, and then 456 g of an aqueous sodium aluminate solution (Al ₂ O ₃ concentration 22 wt%) was mixed, followed by stirring for 3 hours to prepare NaY synthesis slurry (4).
The composition of this time is _{2.8Na 2 O · Al 2 O 3} · 8.5SiO 2 · 108H 2 O in oxide molar ratio.
Subsequently, the NaY synthesis slurry (4) was hydrothermally treated at 95 ° C. for 48 hours and washed to synthesize NaY-type zeolite (4).
The NaY-type zeolite (4) was subjected to shape characteristic measurement and composition analysis, and the results are shown in the table.

Preparation of silica particles (4) In Example 1, silica particles (4) were obtained in the same manner except that 100 g of NaY-type zeolite (4) was used.
With respect to the obtained silica particles (4), shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity) were measured, and the results are shown in the table.

[Example 5]
Synthesis of NaY-type zeolite (5) In Example 4, NaY-type zeolite (5) was synthesized in the same manner except that 522 g of seed (4) prepared in the same manner as in Example 4 was added.
The NaY-type zeolite (5) was subjected to shape characteristic measurement and composition analysis, and the results are shown in the table.

Preparation of silica particles (5) In Example 1, silica particles (5) were obtained in the same manner except that 100 g of NaY-type zeolite (5) was used.
For the obtained silica particles (5), shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity) were measured, and the results are shown in the table.

[Example 6]
Synthesis of NaY-type zeolite (6) NaY-type zeolite (6) was obtained in the same manner as in Example 4 except that 32.5 g of the seed solution (4) was added.
The NaY-type zeolite (6) was subjected to shape characteristic measurement and composition analysis, and the results are shown in the table.

Preparation of silica particles (6) In Example 1, silica particles (6) were obtained in the same manner except that 100 g of NaY-type zeolite (6) was used.
With respect to the obtained silica particles (6), shape characteristic measurement, composition analysis, specific surface area, and refractive index (porosity) were measured, and the results are shown in the table.

[Example 7]
Preparation of silica particles (7) 3900 g of pure water was added to 100 g of NaY-type zeolite (4) prepared in the same manner as in Example 4 and heated to 98 ° C. While maintaining this temperature, a concentration of 3.0 as SiO 2 was obtained. A zeolite / composite in which 380 g of a weight percent sodium silicate aqueous solution and 120 g of a sodium aluminate solution having a concentration of 1.0 wt% as Al2O3 were added in 2 hours to form a composite oxide layer of silica / alumina on the surface of the zeolite particles. An oxide particle dispersion was prepared. At this time, (W _M ) / (W _Z ) was 3.2, and the pH of the dispersion was 12.0. [Step (a)]

Next, after washing with an ultrafiltration membrane to a solid content concentration of 13% by weight, filtration through a capsule filter with an opening of 1 μm, a zeolite / composite oxide particle (7) dispersion having a solid content concentration of 13% by weight is obtained. It was.
To 125 g of the zeolite / composite oxide particle (7) dispersion, 1,125 g of pure water was added, and concentrated hydrochloric acid (concentration 35.5 wt%) was added dropwise to adjust the pH to 1.0, followed by dealumination. Next, 10 mL of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water are added, and the dissolved / desorbed aluminum is separated by an ultrafiltration membrane method and washed to prepare a silica particle (7 _b ) dispersion with a solid content concentration of 20% by weight. did. [Step (b)]

Next, aqueous ammonia is added to the dispersion of silica particles (7 _b ) to adjust the pH of the dispersion to 12.0, then aging at 200 ° C. for 3 hours, cooling to room temperature, and cation exchange resin. (Mitsubishi Chemical Corporation: Diaion SK1B) ion exchange for 3 hours using 400 g, then ion exchange resin (Mitsubishi Chemical Corporation: Diaion SA20A) 200 g ion exchange for 3 hours, Furthermore, 200g of cation exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B) was used for ion exchange at 80 ° C for 3 hours for cleaning, and a silica particle (7 _c ) dispersion with a solid content concentration of 20 wt% was obtained. Obtained. [Step (c)]

The silica particle (7 _c ) dispersion was then dried to obtain silica particles (7).
With respect to the obtained silica particles (7), shape characteristic measurement, composition analysis, specific surface area, and refractive index (porosity) were measured, and the results are shown in the table.

[Example 8]
Preparation of silica particles (8) 3900 g of pure water was added to 100 g of NaY-type zeolite (4) prepared in the same manner as in Example 4 and heated to 98 ° C. While maintaining this temperature, a concentration of 3.0 as SiO 2 was obtained. A zeolite / composite in which 190 g of a weight percent sodium silicate aqueous solution and 120 g of a sodium aluminate solution having a concentration of 1.0 wt% as Al2O3 were added in one hour to form a silica-alumina composite oxide layer on the surface of the zeolite particles. An oxide particle dispersion was prepared.
At this time, (W _M ) / (W _Z ) was 1.8, and the pH of the dispersion was 11.9. [Step (a)]

Next, after washing with an ultrafiltration membrane to obtain a solid content concentration of 13% by weight, it is filtered through a capsule filter having an aperture of 1 μm to obtain a zeolite / composite oxide particle (8) dispersion having a solid content concentration of 13% by weight. It was.
To 1,500 g of pure water was added to 500 g of the oleite / complex oxide particle (8) dispersion, and concentrated hydrochloric acid (concentration 35.5 wt%) was added dropwise to adjust the pH to 1.0, followed by dealumination. Next, 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water are added, and the dissolved and desorbed aluminum is separated by an ultrafiltration membrane method and washed to prepare a silica particle (8 _b ) dispersion with a solid content concentration of 20% by weight. did. [Step (b)]

Next, aqueous ammonia is added to the dispersion of silica particles (8 _b ) to adjust the pH of the dispersion to 12.0, and after aging at 200 ° C. for 3 hours, the solution is cooled to room temperature, and cation exchange resin is obtained. (Mitsubishi Chemical Corporation: Diaion SK1B) ion exchange for 3 hours using 400 g, then ion exchange resin (Mitsubishi Chemical Corporation: Diaion SA20A) 200 g ion exchange for 3 hours, Further, 200 g of cation exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B) was used for ion exchange at 80 ° C. for 3 hours for cleaning, and a silica particle (8 _c ) dispersion with a solid content concentration of 20% by weight was washed. Obtained. [Step (c)]

Then, the silica particle (8 _c ) dispersion was dried to obtain silica particles (8).
With respect to the obtained silica particles (8), shape characteristic measurement, composition analysis, specific surface area, and refractive index (porosity) were measured, and the results are shown in the table.

[Example 9]
Preparation of silica particles (9) In step (c) of Example 4, a cation was added to the silica particle (4 _b ) dispersion without adding aqueous ammonia and without aging at 200 ° C. for 3 hours. Ion exchange using 400 g of exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B) for 3 hours, followed by ion exchange for 3 hours using 200 g of anion exchange resin (Mitsubishi Chemical Corporation: Diaion SA20A) Further, 200 g of a cation exchange resin (Mitsubishi Chemical Co., Ltd .: Diaion SK1B) was used for ion exchange at 80 ° C. for 3 hours for washing, and a silica particle (9) dispersion having a solid content concentration of 20% by weight. Got.
Next, the silica particle (9) dispersion was dried to obtain silica particles (9).
With respect to the obtained silica particles (9), shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity) were measured, and the results are shown in the table.

[Comparative Example 1]
Preparation of silica particles (R1) Concentrated hydrochloric acid (concentration 35.5% by weight) was added dropwise to a NaY-type zeolite (4) dispersion prepared in the same manner as in Example 4 to adjust the pH to 1.0, followed by dealumination. It was.
Next, the aluminum salt dissolved and desorbed by the ultrafiltration membrane was added while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water to obtain a silica particle (R1) aqueous dispersion having a solid content concentration of 20% by weight.
The obtained silica particles (R1) were measured for shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity), and the results are shown in the table.

[Comparative Example 2]
Preparation of silica particles (R2) 3900 g of pure water was added to 100 g of NaY-type zeolite (4) prepared in the same manner as in Example 4 and heated to 98 ° C. While maintaining this temperature, a concentration of 3.0 as SiO 2 was obtained. A fine particle dispersion in which 10.0 g of a weight% sodium silicate aqueous solution and 3.2 g of a sodium aluminate aqueous solution having a concentration of 1.0 wt% as Al 2 O 3 are added over 1 minute to form a zeolite / SiO 2 / Al 2 O 3 composite oxide layer. Got. At this time, (W _M ) / (W _Z ) was 0.09, and the pH of the dispersion was 11.9. [Step (a)]

Next, after washing with an ultrafiltration membrane to a solid content concentration of 13% by weight, the mixture was filtered through a capsule filter having an opening of 1 μm to obtain a zeolite / composite oxide fine particle dispersion.
1,500 g of pure water was added to 500 g of this zeolite / composite oxide fine particle dispersion, and concentrated hydrochloric acid (concentration 35.5 wt%) was added dropwise to adjust the pH to 1.0, followed by dealumination.
Next, while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water, the aluminum salt dissolved and desorbed by the ultrafiltration membrane was separated and washed to obtain an aqueous dispersion of silica particles (R2) having a solid content concentration of 20% by weight.

Next, ammonia water is added to the silica particle (R2) aqueous dispersion to adjust the pH of the dispersion to 12.0, and then aged at 200 ° C. for 3 hours, then cooled to room temperature, and cation exchange resin. (Mitsubishi Chemical Corporation: Diaion SK1B) ion exchange for 3 hours using 400 g, then ion exchange resin (Mitsubishi Chemical Corporation: Diaion SA20A) 200 g ion exchange for 3 hours, Furthermore, 200g of cation exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B) was used for ion exchange at 80 ° C for 3 hours for cleaning, and a silica particle (R2) aqueous dispersion with a solid content concentration of 20 wt% was obtained. Obtained.
The obtained silica fine particles (R2) were measured for shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity), and the results are shown in the table.

[Comparative Example 3]
Preparation of silica particles (R3) 3900 g of pure water was added to 100 g of NaY-type zeolite (4) prepared in the same manner as in Example 4 and heated to 98 ° C. While maintaining this temperature, a concentration of 3.0 as SiO 2 was obtained. 5933 g of a weight% sodium silicate aqueous solution and 1870 g of a sodium aluminate aqueous solution having a concentration of 1.0 wt% as Al 2 O 3 were added over 1 hour to obtain a fine particle dispersion in which a zeolite / SiO 2 / Al 2 O 3 composite oxide layer was formed. . At this time, (W _M ) / (W _Z ) was 50, and the pH of the dispersion was 12.1. [Step (a)]

Next, after washing with an ultrafiltration membrane to a solid content concentration of 13% by weight, the mixture was filtered through a capsule filter having an opening of 1 μm to obtain a zeolite / composite oxide fine particle dispersion.
1,500 g of pure water was added to 500 g of this zeolite / composite oxide fine particle dispersion, and concentrated hydrochloric acid (concentration 35.5 wt%) was added dropwise to adjust the pH to 1.0, followed by dealumination.
Next, the aluminum salt dissolved and desorbed by the ultrafiltration membrane was separated and washed while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water to obtain an aqueous dispersion of silica particles (R3) having a solid content concentration of 20% by weight.

Next, ammonia water is added to the silica particle (R3) aqueous dispersion to adjust the pH of the dispersion to 12.0, and after aging at 200 ° C. for 3 hours, the mixture is cooled to room temperature and cation exchange resin is obtained. (Mitsubishi Chemical Corporation: Diaion SK1B) ion exchange for 3 hours using 400 g, then ion exchange resin (Mitsubishi Chemical Corporation: Diaion SA20A) 200 g ion exchange for 3 hours, Furthermore, 200 g of cation exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B) was used for ion exchange at 80 ° C. for 3 hours for washing, and a silica particle (R3) aqueous dispersion having a solid content concentration of 20 wt% was obtained. Obtained.
The obtained silica particles (R3) were measured for shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity), and the results are shown in the table.

[Comparative Example 4]
Preparation of silica particles (R4) 3900 g of pure water was added to 100 g of NaY-type zeolite (4) prepared in the same manner as in Example 4 and heated to 98 ° C. While maintaining this temperature, a concentration of 3.0 as SiO 2 was maintained. 190 g of a weight% sodium silicate aqueous solution and 60 g of a sodium aluminate aqueous solution having a concentration of 1.0 wt% as Al2O3 were added over 1 hour to obtain a fine particle dispersion in which a zeolite / SiO2 / Al2O3 composite oxide layer was formed. The pH of the dispersion at this time was 11.8. [Step (a)]

Next, after washing with an ultrafiltration membrane to a solid content concentration of 13% by weight, the mixture was filtered through a capsule filter having an opening of 1 μm to obtain a zeolite / composite oxide fine particle dispersion.
Subsequently, it was washed with an ultrafiltration membrane while adding 5 L of pure water to obtain an aqueous dispersion of silica particles (R4) having a solid concentration of 20% by weight.
Next, ammonia water is added to the silica particle (R4) aqueous dispersion to adjust the pH of the dispersion to 12.0, and then aged at 200 ° C. for 3 hours, then cooled to room temperature, and cation exchange resin. (Mitsubishi Chemical Corporation: Diaion SK1B) ion exchange for 3 hours using 400 g, then ion exchange resin (Mitsubishi Chemical Corporation: Diaion SA20A) 200 g ion exchange for 3 hours, Furthermore, 200 g of cation exchange resin (Mitsubishi Chemical Corporation: Diaion SK1B) was used for ion exchange at 80 ° C. for 3 hours for washing, and a silica particle (R4) aqueous dispersion having a solid content concentration of 20 wt% was obtained. Obtained.
The obtained silica fine particles (R4) were measured for shape characteristic measurement, composition analysis, specific surface area and refractive index (porosity), and the results are shown in the table.

[Comparative Example 5]
Preparation of paint for forming transparent film (R5) In Example 2, instead of silica particles (2), silica sol (manufactured by JGC Catalysts & Chemicals: SI-80P, average particle diameter 80 nm, refractive index 1.46, SiO2 concentration 40% by weight) ) Was replaced with methanol, and a transparent film-forming coating material (R5) having a solid content concentration of 5.5% by weight was prepared in the same manner except that it was diluted to a solid content concentration of 5% by weight.

Production of base material with antireflection transparent coating (R5) In the same manner as in Example 2, a hard coat film was formed on the TAC film, and then the coating for transparent coating formation (R5) was applied by the bar coater method (bar # 4). The base material with an antireflection transparent coating (R5) was prepared by applying and curing. At this time, the film thickness of the antireflection transparent coating was 100 nm. This base material with an antireflection transparent coating (R5) had a haze of 0.2%, a total light transmittance of 92%, a reflectance of 0.8%, and a refractive index of the coating of 1.48.
Moreover, when the pencil hardness was measured, when a 4H pencil was used, scratches were generated.
Both the evaluation of adhesion and the evaluation of scratch resistance were Δ.

Claims (21)

The manufacturing method of the silica particle which has a cavity inside characterized by including the following process (a) and (b).
(A) An amount of silicate aqueous solution and / or acidic silicic acid solution and an aqueous solution of an inorganic compound other than alkali-soluble silica as a solid content of zeolite particles (W _Z ), and the zeolite particle surface The weight ratio (W _M ) / (W _Z ) with the amount (W _M ) as the solid content of the composite oxide (hydrate) layer formed in the range of 0.1 to 5.0 A step of simultaneously adding and forming a composite oxide (hydrate) layer of silica and inorganic oxide on the surface of the zeolite particles to prepare a zeolite / composite oxide particle dispersion (b) the zeolite / composite oxide; A step of adding an acid to the particle dispersion to remove at least a part of elements other than silicon constituting the zeolite / composite oxide particles The molar ratio MO _X / SiO ₂ when the aqueous solution of silicate and / or the silica of the acidic silicate solution in the step (a) is represented by SiO ₂ and the inorganic oxide other than silica is represented by MO _X is 0.01 to The method for producing silica particles having cavities inside according to claim 1, which is in a range of 0.18. The method for producing silica particles having a cavity inside according to claim 1 or 2, wherein the following step (c) is performed after the step (b).
(C) Step of aging at 50 to 350 ° C   The method for producing silica particles having a cavity inside according to any one of claims 1 to 3, wherein the pH in the step (a) is in the range of 8 to 14. 5. The cavity according to claim 1, wherein the zeolite is crystalline aluminosilicate, and the zeolite has a SiO ₂ / Al ₂ O ₃ molar ratio in the range of 2 to 20. 5. A method for producing silica particles. Said zeolite has a dice-like structure, a cavity inside according to claim 1, average particle diameter of the zeolite (P _Z) is equal to or is in the range of 0.03~50μm A method for producing silica particles. The zeolite has a plate-like structure, the average thickness (T _Z ) of the zeolite is in the range of 0.01 to 10 μm, and the ratio between the average particle diameter (P _Z ) and the average thickness (T _Z ) of the zeolite _{(P Z) / (T Z} ) the method for producing a silica particle having a cavity therein according to any one of claims 1 to 5, characterized in that the range of 2-20.
A silica particles inside of the outer shell is hollow, and characterized in that the silica particles have a dice-like structure, an average particle diameter of the silica particles (P _S) is in the range of 0.04~55μm Silica particles having cavities inside. A silica particle having a hollow inside of the outer shell, the silica particle having a flat plate structure, and an average thickness (T _S ) of the silica particle is in a range of 0.02 to 11 μm. A silica particle having a cavity inside, wherein a ratio (P _S ) / (T _S ) of an average particle diameter (P _S ) and an average thickness (T _S ) is in a range of 2 to 20.   The silica particles having cavities inside according to claim 8 or 9, wherein the outer shell is non-porous.   11. The silica particle having a cavity inside according to claim 10, wherein a refractive index measured by a standard refractive index liquid method is in a range of 1.10 to 1.44.   The silica particle having a cavity inside according to claim 8 or 9, wherein the outer shell is porous.   The silica particle having a cavity inside according to claim 12, wherein the refractive index measured by a standard refractive index liquid method is in a range of 1.40 to 1.46.   14. The silica particle having a cavity inside according to claim 8, wherein a void ratio of the cavity inside the outer shell is in the range of 5 to 90% by volume. The silica particle having a cavity inside according to any one of claims 8 to 14, obtained by the method for producing a silica particle having a cavity inside according to any one of claims 1 to 7.
It comprises silica particles having cavities inside, a matrix-forming component, and a dispersion medium, and the concentration (C _S ) of the silica particles having cavities inside is in the range of 0.005 to 48% by weight as a solid content, The matrix-forming component concentration (C _M ) is in the range of 0.2 to 59.7% by weight as the solid content, and the total solid content concentration is in the range of 1 to 60% by weight. Coating liquid.   The coating liquid for forming a film according to claim 16, wherein the silica particles having a cavity in the interior are silica particles having a cavity in the interior according to claim 15. The silica particles having cavities in the interior have a plate-like structure, the average thickness (T _S ) of the silica particles is in the range of 0.02 to 0.15 μm, and the average particle diameter (P _S ) is 0.04. The ratio (P _S ) / (T _S ) between the average particle diameter (P _S ) and the average thickness (T _S ) is in the range of 2 to 20 in the range of ˜1 μm. The coating liquid for film formation as described in 2. A content of silica particles having a base and a coating formed on the base, the coating comprising silica particles having cavities therein and a matrix component, and having cavities in the coating (W _A coated substrate, wherein _S ) is in the range of 0.5 to 80% by weight as a solid content, and the content of the matrix component (W _M ) is in the range of 20 to 99.5% by weight.   The coated substrate according to claim 19, wherein the silica particles having a cavity in the interior are silica particles having a cavity in the interior according to claim 15. The silica particles having cavities in the interior have a plate-like structure, the average thickness (T _S ) of the silica particles is in the range of 0.02 to 0.15 μm, and the average particle diameter (P _S ) is 0.04. The ratio (P _S ) / (T _S ) between the average particle diameter (P _S ) and the average thickness (T _S ) is in the range of 2 to 20 in the range of ˜1 μm. A substrate with a coating according to 1.