CN112573526B

CN112573526B - Particles having voids inside shell, method for producing same, coating liquid containing same, and substrate with transparent coating film containing same

Info

Publication number: CN112573526B
Application number: CN202011031633.0A
Authority: CN
Inventors: 二神涉; 熊泽光章; 村口良
Original assignee: JGC Catalysts and Chemicals Ltd
Current assignee: JGC Catalysts and Chemicals Ltd
Priority date: 2019-09-30
Filing date: 2020-09-27
Publication date: 2024-03-29
Anticipated expiration: 2040-09-27
Also published as: KR20210038362A; CN112573526A; JP2021054685A; JP7360294B2; TW202114941A

Abstract

The invention provides a coating liquid capable of obtaining a transparent coating film with excellent adhesion to a substrate, high hardness and high strength. The particles contained in the coating liquid have a dense outer shell containing silica and have voids inside the outer shell thereof. The average particle diameter (D) of the particles is 20 to 250nm, the diameter of the cavity is 0.5 to 0.9 times of the particle diameter, and the utilization of the particles is N ₂ The pore volume of the adsorption method is less than 1.0cm ³ /g, refractive index of particles (n _a ) From 1.08 to 1.34, and the refractive index (n) of the outer shell obtained by the formula (1) _S ) Is 1.38 or more. The substrate with a transparent coating film using the coating liquid has high hardness and high strength, and is particularly useful for antireflection.

Description

Particles having voids inside shell, method for producing same, coating liquid containing same, and substrate with transparent coating film containing same

Technical Field

The present invention relates to particles having voids inside a shell containing silica, and a method for producing the particles. The present invention also relates to a coating liquid for forming a transparent coating film containing the particles and a substrate having a transparent coating film containing the particles.

Background

Conventionally, an antireflection film has been formed on a surface of a substrate such as a sheet body or a lens formed of glass, plastic, or the like in order to prevent reflection on the surface. For example, a film of a low refractive index substance such as a fluororesin or magnesium fluoride is formed on the surface of a glass or plastic substrate by a coating method, a vapor deposition method, a CVD method, or the like. However, these methods are expensive in terms of cost. In this regard, the following methods are known (for example, refer to Japanese patent laid-open publication No. Hei 7-133105). In this method, an antireflection film is formed by applying a coating liquid containing composite oxide colloidal particles composed of silica and an inorganic oxide other than silica, the refractive index of which is 1.36 to 1.44, to the surface of a substrate.

In addition, a method for producing porous hollow particles is known (for example, refer to Japanese patent laid-open publication No. 2001-233611). The hollow particles obtained by this method have a low refractive index. The transparent coating film formed using the hollow particles has a low refractive index and is excellent in antireflection performance.

Further, it is known that if a transparent film containing hollow particles is provided on the front surface of a display device, the antireflection performance of the display device can be improved, and the display performance can be improved (for example, refer to japanese unexamined patent publication No. 2002-079616).

However, if silica-based particles having voids therein are used for the antireflection film, there is a possibility that the hardness and strength (scratch resistance) of the obtained film may be lowered. In addition, if the hollow of the particles is excessively performed in order to achieve a low refractive index of the particles, the particles themselves become fragile. Therefore, the transparent film formed using the particles also becomes insufficient in hardness and strength (scratch resistance).

In this way, if the hardness and strength of the particles are insufficient, there is a problem that at least one of the refractive index, hardness and strength of the transparent coating becomes insufficient.

Disclosure of Invention

To solve such a problem, the following one having a silica-containing housing thereinThe hollow particles on the side are applied to a coating liquid for forming a transparent coating film. The particles have an average particle diameter (D) of 20 to 250nm, and the voids have a diameter of 0.5 to 0.9 times the particle diameter, and N is used ₂ The pore volume of the adsorption method is less than 1.0cm ³ And/g, the refractive index (n) of the shell is obtained by the following formula (1) _s ) Is 1.38 or more, and refractive index (n _a ) 1.08 to 1.34, and a carbon content of 3.0 mass% or less.

[ mathematics 1]

D is the average particle diameter of the particles, D ₀ As an average of the diameters of the hollows inside the housing,

n _a Is the refractive index of the particles, n _p Is the refractive index of the cavity.

The particles have voids inside a dense shell comprising silica. Therefore, the particles have sufficient hardness and strength, and a low refractive index. In the case of a coating liquid containing such particles, a substrate with a transparent coating film having high hardness (pencil hardness) and high strength (scratch resistance) can be obtained.

According to the particles of the present invention, a coating liquid capable of producing a transparent film as described below can be obtained. The transparent coating film has low reflectance, excellent adhesion to a substrate, and high hardness and strength.

Drawings

Fig. 1 is a cross-sectional view of a particle according to an embodiment of the present invention.

Detailed Description

The particles according to the present embodiment are particles having a shell containing silica and a cavity inside the shell (hereinafter, the particles according to the present embodiment may be referred to as particles only). A cross section of the particle is schematically shown in fig. 1.

The average particle diameter D of the particles is 20-250 nm. If the average particle diameter is within this range, the particles can exist stably. In addition, if the average particle diameter is within this range, the particles have high dispersibility even in the coating liquid and in the film, and high transparency, hardness, and strength of the film can be obtained. The average particle diameter is preferably 30 to 150nm, more preferably 30 to 120nm.

The diameter of the hollow inside the shell is 0.5 to 0.9 times the diameter (outer diameter) of the particle. If the diameter of the cavity is within this range, the structure of the shell can be stably maintained, and thus the particles can be stably present. In addition, the film can be obtained with high transparency, hardness and strength. Here, if the diameter of the hollow inside the shell is smaller than 0.5 times the diameter (outer diameter) of the particles, the thickness of the shell may be too thick, and sufficient transparency of the coating may not be obtained. If the diameter of the hollow inside the shell is larger than 0.9 times the diameter (outer diameter) of the particle, there is a possibility that the shell is thin and it becomes difficult to maintain the particle structure. The diameter of the cavity is preferably 0.55 to 0.9 times, more preferably 0.6 to 0.85 times the diameter of the particle.

Utilization of particles N ₂ The pore volume of the adsorption method is less than 1.0cm ³ And/g. If the pore volume is in this range, the structure of the housing is dense. If the pore volume is greater than 1.0cm ³ And/g, the structure of the shell is loose (porous), and the hardness and strength of the shell are weakened. Therefore, it may be difficult to maintain the structure of the case and sufficient hardness and strength of the coating film may not be obtained. The pore volume is preferably less than 0.8cm ³ Preferably less than 0.5cm ³ Per g, most preferably 0.0cm ³ /g。

Refractive index n of particle _a 1.08 to 1.34. If the refractive index is within this range, a transparent coating can be obtained. The refractive index is preferably 1.08 to 1.32, more preferably 1.08 to 1.30.

Refractive index n of the housing _S Is 1.38 or more. If the refractive index n _S If the thickness is 1.38 or more, the outer shell is dense. Refractive index n _S The upper limit of (2) is not particularly set, but is, for example, 1.47. As shown in formula (1), the average particle diameter D of the particles and the average value D of the diameters of the cavities inside the shell _O Refractive index n of particle _a Refractive index n of cavity _P The refractive index n is obtained _S . Refractive index of cavityn _P The state inside the cavity is different. For example, if the inside of the cavity is a gas, the refractive index of the cavity becomes 1.00. If the cavity is filled with a liquid, the refractive index of the cavity becomes the refractive index of the liquid.

If the refractive index n _S When the amount is within this range, a transparent film having sufficient hardness and strength can be obtained. If the refractive index n _S If the hardness of the coating is less than 1.38, the hardness may be insufficient. Refractive index n _S Preferably 1.40 or more, more preferably 1.42 or more.

The carbon content of the particles is 3.0 mass% or less. The carbon contained in the particles is derived from organic compounds such as organosilicon compounds, metal salts, reducing agents, pH adjusters, cleaning solutions, and solvents. In addition to the substances intentionally added for producing the particles, the substances inevitably present in the raw materials and the like are included. If the particles contain an organic compound, the hardness and strength of the outer shell become weak. Therefore, when the particles are used to form a film, the transparency of the film is reduced or the dispersibility of the film is reduced. Therefore, a transparent film having sufficient hardness and strength may not be obtained. As described later, the carbon content derived from such an organic substance can be determined by analyzing the amount of C (carbon). The carbon content is preferably 1.0 mass% or less, more preferably 0.1 mass% or less, and still more preferably 0.05 mass% or less.

For particles ²⁹ Area Q of peak appearing at chemical shift of-78 to-88 ppm in Si-NMR spectroscopy ₁ Area Q of peak appearing at chemical shift of-88 to-98 ppm ₂ Area Q of peak appearing at chemical shift of-98 to-108 ppm ₃ And the area Q of the peak appearing at the chemical shift of-108 to-117 ppm ₄ Preference ratio (Q ₁ The ratio (Q) is substantially 0 ₂ I/Σq) is substantially 0, and the ratio (Q ₃ /Q ₄ ) 0.01 to 0.7. Here Σq=q ₁ +Q ₂ +Q ₃ +Q ₄ 。

The attribute is Q ₁ The peak of (C) is a peak related to a structure obtained by bonding one (-OSi) group and three (-OH) groups to Si atoms. Attributing to Q ₂ The peak of (a) is a peak related to a structure obtained by bonding two (-OSi) groups and two (-OH) groups to Si atoms. Attributing to Q ₃ The peak of (a) is a peak related to a structure obtained by bonding three (-OSi) groups and one (-OH) group on a Si atom. Attributing to Q ₄ Is a peak related to a structure obtained by bonding four (-OSi) groups to a Si atom.

Here, the ratio (Q ₁ /Σq) and ratio (Q ₂ The value of/Σq) is substantially 0, which means that the peak that is inevitably detected due to the detection limit, noise, and the like in the measurement can be determined as "0" even if these are considered, for example. Specifically, the ratio obtained by the above formula is 0.0001 or less. If ratio (Q) ₁ /Σq) and ratio (Q ₂ The ratio (Q) is substantially 0 ₃ /Q ₄ ) When the particle size is 0.01 to 0.7, the particles are dense, and a transparent film having sufficient hardness and strength can be obtained. If ratio (Q) ₁ /Σq) or ratio (Q ₂ If.

Ratio (Q) ₃ /Q ₄ ) Structures less than 0.01 are difficult to obtain. If ratio (Q) ₃ /Q ₄ ) If the ratio is more than 0.7, the ratio of Si-O-Si bonds is small, and therefore the hardness of the coating film may become insufficient. Ratio (Q) ₃ /Q ₄ ) More preferably 0.02 to 0.5, still more preferably 0.03 to 0.2.

The respective contents of elements belonging to alkali metals as impurities of the particles are relative to SiO when the elements are expressed by oxides ₂ Preferably 1ppm or less. If the content is within this range, agglomeration of particles becomes smaller. Therefore, the particles are uniformly dispersed in the coating liquid and the film. Thus, a transparent coating can be obtained. In addition, the stability of the coating liquid also becomes high for the performance of the coating liquid. The film hardness of the film also increases for the performance of the film, and the transparency of the film also increases. Therefore, the content of the alkali metal element is preferably in the above-described range. Here, if the content of the alkali metal element is more than 1ppm, agglomeration of particles increases. The following possibilities therefore exist: the hardness of the film becomes insufficient Or the transparency of the film becomes insufficient. The content of the alkali metal element is more preferably 0.1ppm or less. Here, the alkali metal includes Li, na, K, rb, cs and Fr.

The respective contents of Fe, ti, zn, pd, ag, mn, co, mo, sn, al and Zr as impurities of the particles are preferably less than 0.1ppm, the respective contents of Cu, ni, and Cr as impurities of the particles are preferably less than 1ppb, and the respective contents of U and Th as impurities of the particles are preferably less than 0.3ppb. If the content of these impurities is within the above range, a transparent coating film can be obtained, and is preferable. If the content of these impurities is large, the dispersion is colored, and thus a transparent coating film may not be obtained. In addition, when a coating liquid formed using particles having a large impurity content is used for a semiconductor circuit such as logic and memory, a photosensor, or the like, which requires high purity and high integration, a metal element may cause insulation failure of the circuit, short-circuit the circuit, or decrease light transmittance. This may cause a decrease in dielectric constant of the insulating film, an increase in impedance of the metal wiring, a delay in response speed, an increase in power consumption, and the like. In particular, U and Th produce radioactivity. Therefore, these elements cause malfunction of the semiconductor due to radioactivity, and therefore U and Th are not preferable even in a small amount.

In order to obtain such particles having a small content of impurity elements, it is preferable that the material of the device used for preparing the particles is a material which does not contain these elements and has high chemical resistance. Specifically, the material is preferably teflon (registered trademark), plastic such as FRP or carbon fiber, alkali-free glass, or the like. The raw materials used are preferably purified by distillation, ion exchange or filter removal.

As described above, as a method for obtaining high purity particles, there are a method for preparing a raw material having few impurities in advance and a method for suppressing the mixing of impurities from an apparatus for producing particles. In addition, it is also possible to reduce impurities in particles produced by not sufficiently adopting such a countermeasure.

The shape of the particles and the shape of the voids of the particles are not particularly limited. Examples of the shape include a sphere, an ellipsoid (rugby), a cocoon, a marshmallow, a chain, and a dice. Here, the particle shape is preferably spherical so as to be uniformly dispersed in the transparent film. The shape of the cavity is preferably a shape along the shape of the particle. Although also depending on the thickness of the shell, even in the case where stress is applied to the particles, by making the shell have a uniform thickness, the particles can be maintained to be sufficiently hard and strong. The hollow space is preferably spherical similar to the spherical particles in shape.

In order to reduce the refractive index and obtain a transparent coating, it is preferable that the hollow of the particle is substantially one hollow. Here, the particles may include "particles having a plurality of voids inside the shell" due to aggregation of the particles or the like. The term "the hollow of a particle is substantially one hollow" means that the "proportion of particles in which the hollow on the inner side of the shell is one" is 90% or more. The "proportion of the number of particles in which the hollow space on the inner side of the shell is one" is preferably 95% or more, more preferably 98% or more, still more preferably 99% or more, and most preferably 100%.

The particles preferably contain 90 mass% or more of a silicon component as silica. If the silicon component is within this range, the compatibility of the particles with the matrix-forming component can be improved. Therefore, the particles are highly dispersed in the transparent coating film, and the strength and hardness of the coating film can be improved. The content of the silicon component is more preferably 95% by mass or more, still more preferably 98% by mass or more, particularly preferably 100% by mass, of the silica.

[ method for producing particles ]

The manufacturing method of the present embodiment includes: a first step of, when the oxide of silicon is expressed as SiO ₂ Oxide of inorganic element other than silicon is represented as MO _x In the case of using a molar ratio (MO _x /SiO ₂ ) A step of simultaneously adding a solution containing a compound of silicon and an aqueous solution of a compound of an inorganic element other than alkali-soluble silicon to an alkaline aqueous solution so as to be 0.01 to 2, thereby preparing a dispersion of composite oxide particles a; a second step of obtaining a molar ratio (MO _x /SiO ₂ ) A step of adding a solution containing a compound of silicon and an aqueous solution of a compound of an inorganic element other than alkali-soluble silicon to a dispersion of composite oxide particles a so as to be smaller than the molar ratio of the first step, thereby preparing a dispersion of composite oxide particles b; a third step of adding an acid to the dispersion of the composite oxide particles b to remove at least a part of the elements other than silicon constituting the composite oxide particles b, thereby preparing a dispersion of silica-based particles; and a fourth step of heating the dispersion of silica particles to 200-800 ℃ at a heating rate of 0.3-3.0 ℃/min, and then cooling the dispersion at a rate of 0.04-2.0 ℃/min to a temperature of 100 ℃ or lower. The silica-based particles may be washed as needed.

Each step is described in detail below.

[ first step ]

In the first step, a dispersion of composite oxide particles a having an average particle diameter of 10 to 225nm is prepared. The silicon-containing compound is at least one selected from silicate, acidic silicic acid liquid, and organosilicon compound.

The silicate is preferably 1 or 2 or more kinds of silicate selected from alkali metal silicate, ammonium silicate and organic base silicate. Examples of the alkali metal silicate include sodium silicate (water glass) and potassium silicate. Examples of the organic base include quaternary ammonium salts such as tetraethylammonium salts, and amines such as monoethanolamine, diethanolamine and triethanolamine. The ammonium silicate or the organic base silicate also contains an alkaline solution obtained by adding ammonia, a quaternary ammonium hydroxide, an amine compound, or the like to a silicic acid solution.

As the acidic silicic acid liquid, a silicic acid liquid obtained by removing alkali from an alkali silicate aqueous solution by treating the alkali silicate aqueous solution with a cation exchange resin or the like can be used. Particularly preferably pH2 to pH4, siO ₂ An acidic silicic acid solution having a concentration of about 7 mass% or less.

As the organosilicon compound, an organosilicon compound of the following formula (2) is preferable.

R _n -SiX _4-n ···(2)

Wherein R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, and may be the same or different from each other. Examples of the substituent include an epoxy group, an alkoxy group, a (meth) acryloyloxy group, a mercapto group, a halogen atom, an amino group, and a phenylamino group. X is an alkoxy group having 1 to 4 carbon atoms, a hydroxyl group, a halogen atom or a hydrogen atom. n represents an integer of 0 to 3.

However, among the organosilicon compounds of the formula (2), compounds having n of 1 to 3 lack hydrophilicity. Therefore, in the case of using the compound, it is preferable that the compound is hydrolyzed in advance so that the reaction system can be uniformly mixed. The hydrolysis may be carried out by a known method. As the hydrolysis catalyst, alkali catalysts such as alkali metal hydroxide, ammonia water, and amine can be used. In this case, an acidic solution obtained by removing these basic catalysts after hydrolysis may also be used. In addition, an acidic catalyst such as an organic acid or an inorganic acid may be used to prepare the hydrolysate. In this case, the acidic catalyst is preferably removed by ion exchange or the like after hydrolysis. In addition, the hydrolysate of the obtained organosilicon compound is preferably used in the form of an aqueous solution. The aqueous solution herein means a solution in which the hydrolysate is in a state of no cloudiness as a gel and transparency.

Specifically, examples of the organosilicon compound include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (. Beta. -methoxyethoxy) silane, 3-trifluoropropyltrimethoxysilane, methyl-3, 3-trifluoropropyldimethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma-glycidoxyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-methacryloxypropyltriethoxysilane, gamma-methacryloxypropylmethyldimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-methacryloxypropylmethyldiethoxysilane, gamma-methacryloxypropyltriethoxysilane, N-. Beta. -aminoethylpropyltriaethoxysilane, N-. Beta. -dimethylaminopropyl silane, gamma-dimethylaminopropyl silane, and gamma-glycidoxypropylsilane, gamma-mercaptopropyl trimethoxysilane, trimethylsilanol, methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, trimethylbromosilane, diethylsilane, and the like.

As an oxide of an inorganic element other than silicon (MO _x ) Al may be mentioned ₂ O ₃ 、B ₂ O ₃ 、TiO ₂ 、ZrO ₂ 、SnO ₂ 、CeO ₂ 、P ₂ O ₅ 、Sb ₂ O ₃ 、MoO ₃ 、ZnO ₂ WO (International patent publication) ₃ Etc. 1 or 2 or more. Examples of the composite oxide of an inorganic element other than silicon include TiO ₂ -Al ₂ O ₃ 、TiO ₂ -ZrO ₂ Etc.

As a raw material of such an inorganic oxide, an alkali-soluble inorganic compound is preferable. Examples of the raw material include alkali metal salts or alkaline earth metal salts, ammonium salts, and quaternary ammonium salts of oxo acids of metals or non-metals constituting oxides of inorganic elements other than silicon. Specifically, sodium aluminate, sodium tetraborate, ammonium zirconium carbonate, potassium antimonate, potassium stannate, sodium aluminosilicate, sodium molybdate, ammonium cerium nitrate, sodium phosphate, and the like are suitable as the raw materials.

In order to prepare the dispersion liquid of the composite oxide particles a, an alkaline aqueous solution of a compound of an inorganic element other than silicon, or a mixed aqueous solution is prepared in advance individually. According to the intended silicon oxide (SiO ₂ ) With siliconOxide of external inorganic element (MO _x ) The aqueous solution was gradually added to the alkaline aqueous solution while stirring. The alkaline aqueous solution is preferably adjusted to have a pH of 10 or more. The addition may be continuous or intermittent. In addition, both are preferably added simultaneously.

For the addition ratio of the silicon-containing compound to the inorganic element other than silicon added to the alkaline aqueous solution, when the silicon oxide of the silicon-containing compound is expressed as SiO ₂ Oxide of inorganic element other than silicon is represented as MO _x In the case of using a molar ratio (MO _x /SiO ₂ ) 0.01 to 2. If the molar ratio is within this range, the structure of the composite oxide particles mainly becomes such that silicon and elements other than silicon are bonded to each other through oxygen. That is, a structure in which oxygen atoms are bonded to four bonding sites of silicon atoms and an element M other than silicon is bonded to the oxygen atoms is formed in large amounts. Thus, when the element M other than silicon is removed in the third step described later, the silicon atom can be removed as a silicic acid monomer or oligomer together with the element M while suppressing the destruction of the shape of the composite oxide particles. If the molar ratio is less than 0.01, the void volume of the finally obtained particles is difficult to be sufficiently increased. If the molar ratio is more than 2, the composite oxide particles may be damaged when the elements other than silicon are removed in the third step, and thus it is difficult to obtain particles having voids inside the shell. The molar ratio is preferably 0.1 to 1.5. The addition may be performed while changing the molar ratio so as to gradually decrease. The preparation is preferably performed so that the average particle diameter (Da) of the composite oxide particles after addition is substantially 10 to 225nm (hereinafter, the composite oxide particles in this case may be referred to as primary particles).

However, even if the molar ratio is within the above range, when the average particle diameter of the primary particles is smaller than 10nm, the shells of the finally obtained particles become thick, and therefore the hollow volume of the particles is difficult to be sufficiently increased. If the average particle diameter of the primary particles exceeds 225nm, the removal of the element M other than silicon becomes insufficient in the third step described later. Therefore, the hollow volume of the particles is difficult to be sufficiently increased, and it is difficult to obtain particles having a low refractive index.

In the production method of the present embodiment, when preparing the dispersion liquid of the composite oxide particles a, the dispersion liquid containing the seed particles may be used as a starting material. In this case, as the seed particles, siO may be mentioned ₂ 、Al ₂ O ₃ 、TiO ₂ 、ZrO ₂ 、SnO ₂ CeO, ceO ₂ And 1 or 2 or more kinds of particles. Further, as the composite oxide, siO may be mentioned ₂ -Al ₂ O ₃ 、TiO ₂ -Al ₂ O ₃ 、TiO ₂ -ZrO ₂ 、SiO ₂ -TiO ₂ And SiO ₂ -TiO ₂ -Al ₂ O ₃ And the like. As a dispersion liquid containing seed particles, a sol of these seed particles can be generally used. Such seed particles may be prepared by well known methods. For example, the seed particles may be obtained by hydrolyzing a metal salt, a mixture of metal salts, or a metal alkoxide corresponding to the inorganic oxide by adding an acid or a base, and curing the resulting mixture as necessary.

The method of adding the above-described alkali aqueous solution is performed in the same manner as the method of adding the above-described alkali aqueous solution, and the above-described solution containing a compound of silicon and an aqueous solution of a compound of an inorganic element other than alkali-soluble silicon are added to the seed particle-dispersed alkali aqueous solution. In this case, the pH of the seed particle-dispersed alkaline aqueous solution is preferably adjusted to 10 or more.

Thus, if the composite oxide particles are grown using the seed particles as seeds, the particle diameter control of the grown particles is easy. Thus, particles having uniform particle sizes can be obtained. The addition ratio of the solution of the compound containing silicon to the aqueous solution of the compound of an inorganic element other than alkali-soluble silicon to be added to the seed particle dispersion is in the same range as in the case of adding to the alkaline aqueous solution described above. However, the seed particle fraction was subtracted to calculate the molar ratio (MO _x /SiO ₂ )。

The compound containing silicon and the compound of an inorganic element other than silicon have high solubility on the alkaline side. However, if the two are mixed in the pH range where the solubility is high, the solubility of the oxyacid ions such as silicate ions and aluminate ions is reduced. Therefore, the complex of the oxo acid ion is precipitated and grows as colloidal particles, or the complex of the oxo acid ion is precipitated on the seed particles, and particle growth occurs.

[ second step ]

Then, the catalyst is prepared by reacting a catalyst with a catalyst having a molar ratio (MO _x /SiO ₂ ) A solution containing a compound of silicon and an aqueous solution of a compound of an inorganic element other than alkali-soluble silicon are added to the dispersion of the composite oxide particles a, thereby preparing a dispersion of the composite oxide particles b. Thereby, the composite oxide particles a (primary particles) are grown. The preparation is preferably carried out such that the average particle diameter Db of the composite oxide particles b after addition is 20 to 250 nm.

The compound containing silicon used in the second step and the compound of an inorganic element other than alkali-soluble silicon are selected from the substances exemplified in the first step. These compounds may be the same type of compound as the one used in the first step, or may be another type of compound exemplified in the first step.

If the molar ratio (MO in the first step _x /SiO ₂ ) A is defined as A, the molar ratio (MO _x /SiO ₂ ) If B is used, the ratio B/A is preferably less than 1. If the ratio B/A is less than 1, the surface layer of the composite oxide particles is rich in silica, and the formation of the shell becomes easy. As a result, in the third step described later, the shape of the composite oxide particles is less likely to be broken even if elements other than silicon are removed. Therefore, particles having voids inside the shell containing silica can be stably obtained. If the ratio B/a is 1 or more, it is difficult to produce a shell containing a large amount of silica components, and therefore, if elements other than silicon are removed in the third step, the composite oxide particles may be broken, and the particle shape may not be maintained. Therefore, it may not be possible to obtain a silica-containing shell with voids inside Particles of holes. The ratio B/A is more preferably 0.8 or less, and still more preferably 0.7 or less.

The ratio (Da/Db) of the average particle diameter Da of the composite oxide particles a (primary particles) to the average particle diameter Db of the composite oxide particles b obtained by subjecting the composite oxide particles a (primary particles) to particle growth is preferably 0.5 to 0.9. In the case where the ratio (Da/Db) is less than 0.5, there is a possibility that: the removal of elements other than silicon in the third step becomes insufficient, and the void volume of the obtained particles is difficult to be sufficiently increased, and it is difficult to obtain particles having a low refractive index. If the ratio (Da/Db) is larger than 0.9, particles having voids inside the silica-containing shell may not be obtained because of the difference in particle size (specifically, composite oxide particles having an average particle size (Db) of less than 20 nm). The ratio (Da/Db) is more preferably 0.6 to 0.88, still more preferably 0.7 to 0.85.

In the second step, an electrolyte salt may be added to the dispersion of the composite oxide particles a having an average particle diameter Da of about 10 to 225 nm.

Specific examples of the electrolyte salt include water-soluble electrolyte salts such as sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, sodium sulfate, potassium sulfate, ammonium nitrate, ammonium sulfate, magnesium chloride, and magnesium nitrate.

By adding the electrolyte salt, the formation of the shell becomes easy when the elements other than silicon are removed in the third step. The mechanism for obtaining such an effect is not clear. In this regard, it is considered that the surface of the composite oxide particles after the growth of the particles has increased in silica, and the silica insoluble in acid acts as a protective film for the composite oxide particles.

For the addition amount of the electrolyte salt, when the mole number of the electrolyte salt is expressed as M _E The silicon-containing compound used in the second step is represented by SiO ₂ The mole number of the compound is expressed as M _S When the ratio (M) _E /M _S ) Preferably 0.1 to 10. If ratio (M _E /M _S ) If the amount is less than 0.1, it becomes difficult to sufficiently achieve the effect of adding the electrolyte salt. At a ratio (M _E /M _S ) If the amount is more than 10, it is difficult to improve the effect of adding the electrolyte salt. In addition, perhapsSince the electrolyte salt becomes a buffer, there is a possibility that: the removal of elements other than silicon in the second step or the third step requires much time to impair the particle growth in the second step or the economic efficiency is lowered. Ratio (M) _E /M _S ) More preferably 0.2 to 8. In addition, the electrolyte salt may be added in the entire amount at the beginning of the second step. Alternatively, the electrolyte salt may be continuously or intermittently added when a solution containing a compound of silicon and an aqueous solution of a compound of an inorganic element other than alkali-soluble silicon are added.

Third step

In the third step, an acid is added to the dispersion of the composite oxide particles b to remove at least a part of the elements other than silicon constituting the composite oxide particles b, thereby preparing a dispersion of silica-based particles. In the removal of the element, for example, dissolution removal using mineral acid or organic acid, ion exchange removal by bringing a cation exchange resin into contact with the element, or a combination of these methods is used.

The concentration of the dispersion liquid of the composite oxide particles b varies depending on the treatment temperature, but the composite oxide particles b are preferably 0.1 to 50 mass% in terms of oxide. Here, if the concentration is less than 0.1 mass%, the amount of dissolved silica becomes large, and thus it may become difficult to maintain the shape of the composite oxide particles. In addition, since the dispersion liquid of the composite oxide particles b is of a low concentration, the treatment efficiency becomes low. If the concentration is higher than 50 mass%, the dispersibility of the particles becomes insufficient. In particular, in the case of composite oxide particles containing a large amount of elements other than silicon, it may become difficult to remove the elements other than silicon uniformly or efficiently. The concentration of the dispersion liquid of the composite oxide particles b is more preferably 0.5 to 25 mass%.

The removal of the above elements is preferably carried out until the molar ratio (MO _x /SiO ₂ ) And 0.2 or less. If the molar ratio (MO _x /SiO ₂ ) If the ratio is more than 0.2, the refractive index, hardness and strength of the finally obtained "particles having voids inside the silica-containing shell" may become poorAnd (3) suffices. Molar ratio (MO) _x /SiO ₂ ) More preferably 0.1 or less.

In this step, an electrolyte salt may be added as in the second step. The addition amount is preferably the same as that in the second step, and the above ratio (M _E /M _S ) 0.1 to 10. In addition, the electrolyte salt may be added in the entire amount at the beginning of the third step. Alternatively, the electrolyte salt may be continuously or intermittently added when at least a part of the element other than silicon is removed. However, in the third step, the electrolyte salt added in the second step is not removed so that the ratio (M _E /M _S ) The electrolyte salt is added so as to fall within the above-described range. Ratio (M) _E /M _S ) More preferably 0.2 to 8.

Fourth step

In the fourth step, the silica-based particle dispersion is washed as needed. Thereafter, the dispersion of silica particles is heated to 200 to 800 ℃ at a heating rate of 0.3 to 3.0 ℃/min, and then cooled at a rate of 0.04 to 2.0 ℃/min, whereby the dispersion is at least less than 100 ℃.

If necessary, the dispersion of silica-based particles from which at least a part of the elements other than silicon has been removed may be washed by a well-known washing method such as ultrafiltration. At least a part of the elements other than silicon dissolved by the cleaning is removed. In this case, a part of alkali metal ions and the like in the dispersion is removed in advance, and then ultrafiltration is performed, whereby a dispersion of silica-based particles having high dispersion stability can be obtained.

Further, a part of the dissolved elements other than silicon, alkali metal ions, or the like may be removed by bringing the dispersion liquid from which the elements have been removed into contact with at least one of a cation exchange resin and an anion exchange resin. Further, by heating and cleaning, the silica-based particle dispersion can be efficiently cleaned.

By cleaning the silica-based particle dispersion in this manner, the passage can be effectively reducedThe content of alkali metal or the like as an impurity in "particles having voids inside a shell containing silica" obtained by heat-treating silica-based particles. The content of these is based on the content of the above-mentioned impurities of the "particles having voids inside the shell containing silica". For example, when expressed as oxides, the alkali metal-containing element in the silica-based particles after washing is relative to SiO ₂ 500ppm or less, respectively.

If the respective contents of impurities in the silica-based particles before the cleaning are within the above-mentioned impurity ranges of the particles, the cleaning in this step is not particularly required.

In this way, the dispersion of silica-based particles having a small content of alkali metal or the like is heated to 200 to 800 ℃ at a heating rate of 0.3 to 3.0 ℃/min. After heating, the dispersion is cooled at a rate of 0.04-2.0 ℃/min to a temperature of at least 100 ℃.

In this embodiment, the dispersion of silica-based particles is heated to precipitate a thermally dissociable silicon component on the silica-based particles. Further, the dispersion of silica-based particles is cooled to deposit and immobilize the thermally dissociable silicon component on the silica-based particles. By doing so, "particles having voids inside the shell containing silica" are produced.

Such a silica-containing shell is dense, and thus the inside thereof is kept in a gas phase or a liquid phase having a low refractive index. Therefore, the particles themselves become dense and low refractive index particles.

Here, if the temperature rise rate is less than 0.3 ℃/min, the time to rise to the target temperature is excessively used, and the production efficiency is not good. If the temperature rise rate is faster than 3.0 ℃/min, dissolution of the silicon component in the particles occurs rapidly. Therefore, densification of the particles may not be achieved. The temperature rising rate is preferably 0.5 to 2.5 ℃/min, more preferably 0.8 to 2.2 ℃/min.

Then, if the temperature of the heating is less than 200 ℃, the precipitation of the silicon component in the particles may become insufficient. Even if the temperature exceeds 800 ℃, it is difficult to further increase precipitation in particles, and the manufacturing cost may increase. The dispersion of silica particles may be cooled after the dispersion of silica particles is heated to a target temperature. However, in order to stably produce "particles having voids inside a shell containing silica", it is preferable to maintain the temperature of the dispersion of the silica-based particles after heating for 30 minutes or more. The temperature for heating is preferably 360 to 750 ℃, more preferably 400 to 750 ℃.

Then, if the cooling rate is less than 0.04 ℃/min, the manufacturing cost may increase. If the cooling rate is higher than 2.0 ℃/min, the silicon component may be deposited on the silica-based particles, but densification of the particles may not be achieved. The cooling rate is preferably 0.08 to 1.8 ℃/min, more preferably 0.12 to 1.5 ℃/min.

The temperature of the cooling is less than 100 ℃. In order to facilitate the treatment, the temperature of the dispersion of silica particles may be lowered to normal temperature. However, as described later, when the temperature of the silica-based particle dispersion is raised again, if the temperature is lowered too much during the temperature lowering, a lot of time may be required for the temperature lowering and the temperature raising, or additional energy may be required. When the temperature of the cooling is lower than 100 ℃, the cooling may be performed at an increased speed without being limited to the above-described range of the cooling speed.

In the fourth step, the above-described heating and cooling operations (processes) are preferably repeated a plurality of times. By repeating this operation, the dissolution and deposition of the silicon component are also repeated. Accordingly, a more dense and lower refractive index "particle having a cavity inside a shell containing silica" can be obtained. The conditions for repeating the operation may be the same each time, or the temperature rising rate or temperature may be changed.

The coating material for forming a coating film obtained by using the thus obtained "particles having voids inside a silica-containing shell" has improved stability, film coating properties, and the like. In addition, when such particles are used for a film or the like, it is difficult for a substance having a high refractive index such as a matrix forming component to enter the inside of the particle shell. Thus, a transparent film having a low refractive index can be obtained. In addition, the film has excellent adhesion to a substrate, high hardness and strength.

In the present embodiment, it is preferable that a silica source having a small impurity content is added to the silica-based particle dispersion liquid after the third step, that is, between the third step and the fourth step. The silica source is, for example, a silica sol, a silicic acid solution or an organosilicon compound. By adding the silica source before the hydrothermal treatment in the fourth step, it is possible to obtain "particles having voids inside the silica-containing shell" which are more densified, have a low refractive index, and have high hardness and strength.

The addition of the silica source is performed in order to more positively dissolve and deposit the silicon component in the fourth step. Therefore, the silica source added is preferably fine. For example, when a silica sol is used as the silica source, the average particle diameter is preferably substantially less than 30nm, although the average particle diameter is based on the average particle diameter of silica-based particles. In the case where the silica source to be used is an organosilicon compound, the organosilicon compound represented by the formula (2) in the first step may be used. When an organosilicon compound having n of 0 in the formula (2) is used, a partial hydrolysate of the organosilicon compound is preferably used. The silica sources may be used alone or in combination.

In this way, in the present embodiment, it is preferable that at least one of the organosilicon compound represented by the formula (2) and the partial hydrolysate thereof is added to the silica-based particle dispersion liquid between the third step and the fourth step.

The silica source is preferably SiO as the silica source per 100 parts by mass of the silica-based particles ₂ 1 to 200 parts by mass as a solid component. Here, if the amount of the silica source is less than 1 part by mass, the effect of addition thereof cannot be sufficiently obtained. Even if the amount of the silica source is more than 200 parts by mass, densification of the particles is not further improved. And due to the refractive index of the particles Rising, there is a possibility that particles having a desired refractive index cannot be obtained. The amount of the silica source is more preferably 5 to 100 parts by mass, still more preferably 20 to 55 parts by mass.

In the case of adding these silica sources, the operation of increasing and decreasing the temperature is also preferably repeated a plurality of times as described above. From the viewpoint of forming a coating layer and densification of particles, it is preferable to add the silica source before heating.

The silica sources may be added only once before the temperature is raised, or may be added at each repetition of the operations of raising and lowering the temperature. Alternatively, the addition of these silica sources may be performed intermittently.

In the present embodiment, it is preferable that the particles are surface-treated by adding an organosilicon compound after the fourth step.

As the organosilicon compound to be added, an organosilicon compound having n of 1 to 3 represented by the formula (2) in the first step is preferably used. Here, when an organosilicon compound having n of 0 is used, a partial hydrolysate of the organosilicon compound is preferably used.

In the surface treatment of the particles, an alcohol dispersion of the particles is prepared, and a predetermined amount of an organosilicon compound represented by formula (2) and water are added to the dispersion. Thus, the surface treatment of the particles is performed by hydrolyzing the organosilicon compound. In the hydrolysis, an acid or a base is used as a catalyst for hydrolysis, as necessary.

Preferably, the organosilicon compound is used as R with respect to 100 parts by mass of the particles _n -SiO _(4-n)/2 0.1 to 100 parts by mass and is present as a solid component. If the particles are surface-treated with an organosilicon compound, the compatibility of the particles with the matrix-forming component can be improved.

Here, if the amount of the organosilicon compound is less than 0.1 parts by mass, the effect of addition thereof cannot be sufficiently obtained. On the contrary, the dispersibility of the particles may become insufficient, and the resulting transparent coating film may have haze defects. Even if the amount of the organosilicon compound is more than 100 parts by mass, the dispersibility of the particles cannot be further improved. Furthermore, since the sites (sites) to be bonded to the matrix are increased, there is a possibility that the adhesion of the particles to the substrate becomes insufficient. The amount of the organosilicon compound is more preferably about 2 to 80 parts by mass, and still more preferably 3 to 50 parts by mass.

[ coating liquid for Forming transparent film ]

The particles described above can be used in a coating liquid for forming a transparent coating film. That is, the coating liquid contains particles, a matrix-forming component, and an organic solvent. The coating liquid may contain, in addition to these, additives such as a polymerization initiator, a leveling agent, and a surfactant. Next, the main components contained in the coating liquid will be described.

The concentration of the particles in the coating liquid is preferably 5 to 95% by mass based on the total amount of the particles contained in the coating liquid and the solid components such as the matrix-forming component. If the concentration of the particles is less than 5 mass%, the refractive index of the coating film may not be sufficiently lowered. Conversely, if the concentration of the particles is more than 95 mass%, cracks may occur in the coating film; the adhesiveness of the coating film to the substrate may become insufficient; and may cause deterioration in hardness, strength, transparency, haze, and the like. The concentration of the particles is more preferably 10 to 85 mass%, and still more preferably 20 to 70 mass%.

As the matrix-forming ingredient, an organic resin matrix-forming ingredient is suitable. Examples of the matrix-forming component include ultraviolet curable resins, thermosetting resins, and thermoplastic resins.

Examples of the ultraviolet curable resin include (meth) acrylic resins, γ -aminoacetoxy resins, urethane resins, and vinyl resins. Examples of the thermosetting resin include urethane resins, melamine resins, silicone resins, butyral resins, reactive silicone resins, phenolic resins, epoxy resins, unsaturated polyester resins, and thermosetting acrylic resins. Examples of the thermoplastic resin include polyester resins, polycarbonate resins, polyamide resins, polyphenylene ether resins, thermoplastic acrylic resins, chlorinated vinyl resins, fluorine resins, vinyl acetate resins, and silicone rubbers. These resins may be 2 or more kinds of copolymers or modified products, or may be used in combination. In addition, these resins may be emulsion resins, water-soluble resins, or hydrophilic resins.

The components forming these resins are preferably monomers or oligomers in terms of dispersibility of the particles and easiness of the coating film.

The concentration of the matrix-forming ingredient in the coating liquid is preferably 5 to 95% by mass based on the total amount of the solid components such as the particles and the matrix-forming ingredient contained in the coating liquid. When the concentration of the matrix-forming component is less than 5 mass%, filming is difficult. In addition, even if a film is obtained, cracks may occur in the film; the adhesion of the coating film to the substrate may also become insufficient; and the hardness, strength, transparency, haze, etc. may be deteriorated. Conversely, if the concentration of the matrix-forming component is more than 95 mass%, the amount of particles is small, and therefore the refractive index may not be sufficiently lowered. The concentration of the matrix-forming component is more preferably 15 to 90% by mass, still more preferably 30 to 80% by mass.

As the organic solvent, a solvent capable of uniformly dispersing particles and dissolving or dispersing an additive such as a matrix forming component and a polymerization initiator is used. Among them, hydrophilic solvents and polar solvents are preferable. Examples of the hydrophilic solvent include alcohols, esters, glycols, and ethers. Examples of the polar solvent include esters and ketones.

Examples of the alcohols include methanol, ethanol, propanol, 2-propanol, butanol, diacetone alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol.

Examples of the esters include methyl acetate, ethyl acetate, isopropyl acetate, propyl acetate, isobutyl acetate, butyl acetate, isoamyl acetate, amyl acetate, 3-methoxybutyl acetate, 2-ethylbutyl acetate, cyclohexyl acetate, and ethylene glycol monoacetate.

Examples of the diols include ethylene glycol and hexylene glycol.

Examples of the ethers include 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, propylene glycol monoethyl ether, and propylene glycol monomethyl ether acetate.

Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, butyl methyl ketone, cyclohexanone, methylcyclohexanone, dipropyl ketone, methyl amyl ketone, and diisobutyl ketone.

As the polar solvent, dimethyl carbonate, toluene, and the like are additionally included.

These may be used alone or in combination of 2 or more.

As the additive, any additive that has been conventionally used for forming an antireflection film can be used. For example, a polymerization initiator, a leveling agent, or the like is used to promote polymerization of the matrix-forming component and improve film formability.

Examples of the polymerization initiator include bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide, bis (2, 6-dimethoxybenzoyl) 2, 4-trimethyl-pentylphosphine oxide, 2-hydroxymethyl-2-methylphenyl-propan-1-one, 2-dimethoxy-1, 2-diphenylethan-1-one, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropane-1-one.

Examples of the leveling agent include an acrylic leveling agent, a silicone leveling agent, and an acrylic silicone leveling agent. As these leveling agents, those having a fluorine group are preferably used.

The concentration of these additives in the coating liquid is calculated as the solid content during film formation, and for convenience, the additives are calculated as the matrix-forming component and calculated as the matrix after film formation.

The concentration of the solid content of the coating liquid (the ratio of the solid content of the particles to the solid content of the matrix-forming component to the coating liquid) is preferably 0.1 to 60 mass%. If the solid content concentration of the coating liquid is less than 0.1 mass%, it becomes difficult to apply the coating material because the concentration stability of the coating material is low. Therefore, it may be difficult to obtain a uniform coating. In addition, the haze and the appearance are deteriorated, and thus productivity and manufacturing reliability may be lowered. In contrast, if the solid content concentration of the coating liquid is higher than 60 mass%, there is a possibility that the stability of the coating liquid may be deteriorated. In addition, since the viscosity of the coating liquid increases, there is a possibility that the coating property may decrease. Further, the haze of the coating film may be high, the surface roughness may be high, and the strength may be insufficient. The solid content concentration of the coating liquid is more preferably 1 to 50 mass%.

[ method for producing transparent coated substrate ]

The substrate with a transparent coating film comprises a substrate and a transparent coating film formed on the substrate. In the production of a substrate with a transparent coating, the transparent coating is formed on the substrate using the coating liquid described above.

Specifically, after the coating liquid is applied to the substrate, drying and ultraviolet irradiation are performed, whereby a transparent film is formed on the substrate. The method of applying the coating liquid is not particularly limited as long as it is a method capable of forming a transparent coating film on a substrate. As a coating method of the coating liquid, a well-known method can be employed. Examples of the known method include a spray coating method, a spin coating method, a roll coating method, a bar coating method, a slit coating printing method, a gravure printing method, and a micro gravure printing method. In drying, for example, the solvent is evaporated and removed by heating the substrate to a temperature of 50 to 150 ℃. Thereafter, ultraviolet rays are irradiated to the base material to promote polymerization of the resin component, thereby realizing hardness of the coating film. The transparent coating is mainly composed of a matrix (resin) component and particles.

Thus, a transparent film-coated substrate having a transparent film formed on the substrate was produced. The transparent coating contains particles and a matrix. In the transparent film, the ratio of the particles in the coating liquid to the solid content of the matrix-forming component becomes the ratio of the particle component to the matrix in the film as it is. As described above, the additive remaining as a solid component among the additives in the coating liquid is counted as a matrix.

The thickness of the transparent coating is preferably 80 to 350nm. If the film thickness is less than 80nm, the strength and scratch resistance of the film may become insufficient. In addition, since the film is too thin, sufficient antireflection performance cannot be obtained. In contrast, if the film thickness is thicker than 350nm, cracks tend to occur in the film, and thus the strength of the film may become insufficient. In addition, since the film is too thick, there is a case where the reflection preventing performance is lowered. In addition, when the shrinkage is very large, there is a possibility that cracks may occur. The film thickness is more preferably 85 to 220nm, still more preferably 90 to 110nm.

The refractive index of the transparent film is preferably 1.10 to 1.45.

It is difficult to obtain a transparent coating having a refractive index of less than 1.10. If the refractive index exceeds 1.45, the refractive index of the base material or the refractive index of another film formed as a lower layer of the transparent film formed as needed may be different, but the reflection preventing performance may be insufficient.

The refractive index of the transparent coating film of the present embodiment was measured by ellipsometry (EMS-1 manufactured by ULVAC Co.). The refractive index of the transparent coating is more preferably 1.15 to 1.35.

The light transmittance of the base material with the transparent coating is preferably 85.0% or more. If the light transmittance is less than 85.0%, there is a possibility that the sharpness of the image becomes insufficient in a display device or the like. The light transmittance is more preferably 90.0% or more.

The haze of the transparent film-coated substrate is preferably 3% or less, more preferably 0.3% or less.

The reflectance of the transparent film-coated substrate is preferably 2.0% or less, more preferably 1.2% or less.

The strength (scratch resistance) of the transparent coating film was increased by a load of 1kg/cm ² The steel wool #0000 was slipped over a transparent film for evaluation. Preferably, no streak is observed on the film surface at a time point when the number of sliding times is at least 100, more preferably no streak is observed at a time point when the number of sliding times is 500, and even more preferably no streak is observed at a time point when the number of sliding times is 1000.

The pencil hardness of the transparent coating is preferably 2H or more. When the pencil hardness is less than 2H, the hardness is insufficient as an antireflection film. The pencil hardness is more preferably 3H or more, and still more preferably 4H or more.

The substrate may be any of the well-known substrates. For example, transparent resin substrates such as polycarbonate, acrylic resin, polyethylene terephthalate (PET), triacetyl cellulose (TAC), polymethyl methacrylate resin (PMMA), and Cyclic Olefin Polymer (COP) are preferable. The adhesion between these substrates and the transparent film formed from the coating liquid is excellent. Therefore, by using these base materials, a base material with a transparent coating film excellent in hardness, strength, and the like can be obtained. Thus, it is particularly suitable for use with thin substrates. The thickness of the base material is not particularly limited, but is preferably 10 to 100. Mu.m, more preferably 20 to 80. Mu.m.

Further, a substrate with a coating film in which another coating film is formed on such a substrate may be used. Examples of the other coating film include a primer film, a hard coat film, a high refractive index film, and a conductive film, which are conventionally known.

Hereinafter, examples of the present invention will be described. Here, particles surface-treated with an organosilicon compound are exemplified.

Example 1

< production of particle (P1) having voids inside a silica-containing outer shell >

50g of an aqueous dispersion of seed particles (USBB-120, manufactured by Nisshakugaku chemical Co., ltd., average particle diameter 25nm, solid content concentration 20% by mass, al in the solid content) ₂ O ₃ Content 27 mass%) of pure water was added thereto at 9950g. Thereafter, 1 mass% sodium hydroxide was added to the dispersion, and the pH of the dispersion was adjusted to 11.0. Thereafter, the dispersion was heated to 98℃and SiO was added to the dispersion ₂ 1.87kg of an aqueous sodium silicate solution having a concentration of 1.5 mass% as Al ₂ O ₃ 1.87kg of an aqueous sodium aluminate solution having a concentration of 0.5% by mass. Thereafter, the dispersion was washed by centrifugal sedimentation. Thus, a dispersion of the composite oxide particles (a-1) was obtained. The composite oxide particles (a-1) had an average particle diameter of 44nm.

The dispersion of the composite oxide particles (a-1) was heated to 98℃and SiO was added to the dispersion ₂ 6.31kg of an aqueous sodium silicate solution having a concentration of 1.5 mass% as Al ₂ O ₃ 2.10kg of an aqueous sodium aluminate solution having a concentration of 0.5% by mass. Thereafter, the dispersion was washed with an ultrafiltration membrane to a solid content concentration of 13 mass%. Thereafter, the dispersion was filtered by a capsule filter having a pore size of 1. Mu.m. Thus, a dispersion of the composite oxide particles (b-1) was obtained. The composite oxide particles (b-1) had an average particle diameter of 58nm.

1125g of pure water was added to 500g of the dispersion of the composite oxide particles (b-1). Further, concentrated hydrochloric acid (concentration: 35.5 mass%) was added dropwise to the dispersion so that the pH of the dispersion became 1.0. The dispersion was washed by adding 10L of aqueous hydrochloric acid solution having a pH of 3 and 5L of pure water to the dispersion and separating the dissolved aluminum salt using an ultrafiltration membrane. Thus, a dispersion of silica-based particles (C-1) having a concentration of 5% by mass was obtained.

Next, 12.8g of a silica sol (CATALOID SI-550 manufactured by Nitro catalyst Co., ltd., average particle diameter of 5nm, solid content concentration of 20 mass%, na) as a silica source was added to 100g of the dispersion of the silica particles (C-1) ₂ O concentration 0.8 mass%) was thoroughly stirred. Thereafter, the pH of the dispersion was adjusted to 10.8 by adding ammonia water. The dispersion was warmed from 25 ℃ to 360 ℃ over 335 minutes and held for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 420 minutes. Thereafter, the dispersion was again warmed from 25℃to 360℃over 335 minutes and maintained for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 420 minutes. Thereafter, the same operation was performed again (total 3 times). Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, particles having voids inside the silica-containing shell are obtainedAn aqueous dispersion of the seed (P1). The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P1) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P1) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P1), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with methyl isobutyl ketone (MIBK) using an evaporator. Thus, a MIBK dispersion of particles (P1) having a solid content of 20% by mass was obtained.

The production conditions of the particles (P1) are shown in table 1. The properties of the particles (P1) measured by the following methods are shown in table 2 (the same applies to the examples and comparative examples).

The physical properties of the particles (P1) were measured by image analysis. Specifically, first, the MIBK dispersion of the particles (P1) was diluted to 0.01 mass% with methanol, and then dried on a collodion film of a copper wire (copper cell) for an electron microscope. Then, photographs were taken of the above samples at a magnification of 100 ten thousand times by a field emission transmission electron microscope (HF 5000, manufactured by hitachi high technology, ltd.). For any 1000 particles in the obtained photograph projection images (SEM images, TEM images), measurement was performed by the following methods (1) to (5).

(1) Average particle diameter (D)

The area of the particle (P1) was obtained by image processing of SEM images. From this area, the equivalent circle diameter was obtained. The average value of the equivalent circle diameters was used as the average particle diameter of the particles.

(2) Diameter of cavity

From the TEM photograph, the area of the cavity inside the shell of the particle (P1) was obtained. From this area, the equivalent circle diameter was obtained, and the equivalent circle diameter was used as the cavity diameter. In addition, the average value of the cavity diameter is defined as D _O 。

(3) Particle shape

The ratio of the short diameter to the long diameter of the particle (P1) was obtained from the SEM image. Here, if the average value of the ratio (long diameter/short diameter) is less than 1.2, the particle shape is determined to be spherical.

(4) Proportion of particles with one hollow shape

From the TEM photograph, the ratio of the short diameter to the long diameter of the hollow inside the shell of the particle (P1) was obtained. Here, if the average value of the ratio (long diameter/short diameter) is less than 1.2, the particle shape is determined to be spherical. The number of voids in the particles was measured, and the ratio was determined.

(5) By N ₂ Pore volume of adsorption method

The MIBK dispersion of particles (P1) was dried at 105℃using an evaporator. 1g of the powder was collected by a sample tube, and the nitrogen gas was adsorbed onto the powder by a nitrogen adsorption apparatus (BELSORP-miniII (manufactured by MicrotracBEL Co., ltd.), to measure the pore volume.

(6) Refractive index of particles (n _a )

The MIBK dispersion of the particles (P1) was collected in an evaporator, and the dispersion medium was evaporated. The evaporated product was then dried at 120 ℃ to a powder. Two or three drops of a standard refractive liquid having a known refractive index were dropped onto a glass plate, and the above powder was mixed therewith. This was done using various standard refractive fluids. The refractive index of the standard refractive liquid when the mixed liquid becomes transparent was used as the refractive index of the silica-based hollow particles.

(7) Shell refractive index of particle (n _s )

The average particle diameter (D) of the particles obtained by the above method and the average value (D) of the cavity diameter inside the shell were used _O ) And refractive index (n) _a ) The shell refractive index (n) of the particles was obtained by the following formula _s )。

[ math figure 2]

D is the average particle diameter of the particles, D ₀ Is the average of the diameters of the voids inside the shell,

n _a is the refractive index of the particle, n _p Is the refractive index of the cavity

(8) Carbon content

The MIBK dispersion of the particles (P1) was dried at 120℃and calcined at 400 ℃. The calcined product was measured by using a carbon-sulfur analyzer (EMIA-320V manufactured by HORIBA), to obtain the carbon content in the particles (P1).

(9) By means of ²⁹ Q of Si-NMR ₁ 、Q ₂ 、Q ₃ 、Q ₄ And the ratio thereof

The MIBK dispersion of particles (P1) was placed in a dedicated glass cell. To this dispersion was added 5 mass% of tetramethylsilane as a reference substance. Then, the dispersion was measured by an NMR apparatus (JNM-EX 270 type manufactured by Nippon electronics Co., ltd.) and analysis software Excalibur manufactured by Nippon electronics Co., ltd.). More specifically, the Single pulse non-decoupling method is used for ²⁹ Area of peak appearing at chemical shift of-78 to-88 ppm (Q) ₁ ) Area of peak appearing at chemical shift of-88 to-98 ppm (Q ₂ ) Area of peak appearing at chemical shift of-98 to-108 ppm (Q ₃ ) And the area (Q) of the peak appearing at a chemical shift of-108 to-117 ppm ₄ ) The ratio (Q ₁ /Σq), ratio (Q ₂ /Σq) and ratio (Q ₃ /Q ₄ )。

(10) Alkali metal and other element content

The alkali metal content, fe, ti, zn, pd, ag, mn, co, mo, sn, al and Zr content, cu, ni and Cr content, and U and TH content in the particles (P1) were measured as follows. First, the particles are dissolved in hydrofluoric acid, the hydrofluoric acid is removed by heating, and then pure water is added as necessary, thereby obtaining a solution. The content was measured by measuring the obtained solution using an ICP inductively coupled plasma atomic emission spectrometry mass spectrometer (for example, ICPM-8500 manufactured by shimadzu corporation).

(11) Silica content

The MIBK dispersion of particles (P1) was dried at 120℃for 12 hours. Using a fluorescent X-ray analyzer (Hitachi High-Tech, co., ltd.)The dried product was measured by EA600VX, science, to obtain Silica (SiO) ₂ ) Is contained in the composition.

< production of coating liquid (1) for Forming anti-reflection transparent coating >

The MIBK dispersion of the particles (P1) was diluted so that the solid content concentration became 5 mass%. A coating liquid (1) for forming a transparent coating film was prepared by sufficiently mixing 50g of the diluted dispersion, 1.67g of an acrylic resin (HITALOID 1007, hitachi chemical Co., ltd.) and 52.6g of a 1/1 (mass ratio) mixed solvent of isopropyl alcohol and n-butyl alcohol. The coating liquids for forming the transparent coating are shown in table 3 (the same applies to the examples and comparative examples below).

< production of substrate (1) with anti-reflection transparent coating >

A hard coat paint (ELCOM HP-1004 manufactured by Nisshaku catalyst Co., ltd.) was applied to a TAC film (FT-PB 80UL-M manufactured by PANAC Co., ltd.) by a bar coating method (# 18), and the film was dried at 80℃for 120 seconds. Thereafter, by irradiation of 300mJ/cm ² The hard coat film is produced by curing the hard coat film coating material by ultraviolet rays. The film thickness of the hard coat film was 8. Mu.m.

Next, the coating liquid (1) for forming the transparent coating film for preventing reflection was coated on the TAC film on which the hard coating film was formed by the bar coating method (# 4), and dried at 80 ℃ for 120 seconds. Thereafter, at N ₂ Irradiation under atmosphere 600mJ/cm ² The coating liquid (1) is cured to produce the substrate (1) with the anti-reflection transparent coating.

The following items were measured on a substrate (1) with an antireflection transparent coating. The measurement results are shown in table 3 (the same applies to the examples and comparative examples below).

(12) Film thickness, refractive index, and reflectance

The film thickness, film refractive index and reflectance of light having a wavelength of 550nm of the base material (1) having the antireflection transparent film were measured using an ellipsometer (EMS-1, ULVAC Co.).

(13) Total light transmittance, haze

The total light transmittance and haze of the substrate (1) with the antireflection transparent coating were measured using a haze meter (manufactured by Suga tester).

(14) Adhesion properties

The surface of the base material (1) having the antireflection transparent coating was formed with 11 parallel scratches at a pitch of 1mm in the longitudinal and transverse directions by a knife, and 100 squares were produced. A cellophane tape was attached to the surface formed with the square shape. Next, the number of squares remaining without peeling the film when peeling the cellophane tape was classified into the following 3 grades, whereby the adhesiveness was evaluated.

The number of remaining squares is 90 or more: excellent (L.) Excellent

The number of residual squares is 85 to 89: o (circle)

The number of remaining squares is 84 or less: and (V)

(15) Determination of scratch resistance

At a load of 1500g/cm ² The #0000 steel wool was slid 100 times over the surface of the film. The surface of the film was visually observed, and the scratch resistance was evaluated according to the following criteria.

Evaluation reference:

no streak was seen: excellent (L.) Excellent

Only a small number of streaks were seen: o (circle)

A large number of streaks were seen: and (V)

The whole surface is ground: x-shaped glass tube

(16) Hardness of pencil

The pencil hardness was measured according to JIS K5400 by using a pencil hardness tester. That is, the pencil was set on the surface of the transparent coating so as to form an angle of 45 degrees. The pencil was pulled at a constant speed while applying a load to the pencil with a predetermined weight, and whether or not the surface of the transparent film had scratches was observed.

Example 2

< production of particles (P2) having voids inside a silica-containing outer shell >

To an aqueous dispersion of seed particles (USBB-120, manufactured by Nisshakugaku Kagaku Co., ltd., average particle diameter of 25nm, solid content concentration of 20 mass%, al in the solid content) ₂ O ₃ Content 27 mass%) 750g pure water 29250g was added. Which is a kind ofAfter that, 1 mass% sodium hydroxide was added to the dispersion, and the pH of the dispersion was adjusted to 11.0. Thereafter, the dispersion was heated to 98℃and SiO was added to the dispersion ₂ 5.83kg of an aqueous sodium silicate solution having a concentration of 1.5 mass% as Al ₂ O ₃ 5.83kg of an aqueous sodium aluminate solution having a concentration of 0.5% by mass. Thereafter, the dispersion was washed by centrifugal sedimentation. Thus, a dispersion of the composite oxide particles (a-2) was obtained. At this time, the average particle diameter of the composite oxide particles (a-2) was 225nm.

The dispersion of the composite oxide particles (a-2) was heated to 98℃and added as SiO ₂ 2.21kg of an aqueous sodium silicate solution having a concentration of 1.5 mass% as Al ₂ O ₃ 0.74kg of an aqueous sodium aluminate solution having a concentration of 0.5 mass%. Thereafter, the dispersion was washed with an ultrafiltration membrane to a solid content concentration of 13 mass%. Thereafter, the dispersion was filtered through a capsule filter having a sieve size of 1. Mu.m. Thus, a dispersion of the composite oxide particles (b-2) was obtained. The composite oxide particles (b-2) had an average particle diameter of 240nm.

1125g of pure water was added to 500g of the dispersion of the composite oxide particles (b-2). Concentrated hydrochloric acid (concentration: 35.5 mass%) was added dropwise to the dispersion so that the pH of the dispersion became 1.0. The dissolved aluminum salt was separated by an ultrafiltration membrane while adding 10L of an aqueous hydrochloric acid solution having a pH of 3 and 5L of pure water to the dispersion, and the dispersion was washed. Thus, a dispersion of silica-based particles (C-2) having a concentration of 5% by mass was obtained.

Next, 2.5g of a silica sol (CATALOID SI-50, manufactured by Nitro catalyst Co., ltd., average particle diameter 25nm, solid content concentration 48 mass%, na) as a silica source was added to 100g of the dispersion of silica particles (C-2) ₂ O concentration 0.5 mass%) was thoroughly stirred. Thereafter, the pH of the dispersion was adjusted to 10.5 by adding ammonia water. The dispersion was warmed from 25 ℃ to 360 ℃ over 335 minutes and held for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 420 minutes. Thereafter, the dispersion was again warmed from 25℃to 360℃over 335 minutes and maintained for 24 hours. Thereafter, the dispersion was cooled for 420 minutesBut to 25 ℃. Thereafter, the same operation was performed again (total 3 times). Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P2) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P2) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P2) having a solid content of 20 mass% was prepared.

Next, 2g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P2), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P2) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (2) for Forming anti-reflection transparent coating film and substrate (2) having the coating film)

An antireflective transparent coating forming coating liquid (2) and a antireflective transparent coating-carrying substrate (2) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (P2) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Example 3

< production of particle (P3) having voids inside a silica-containing outer shell >

To an aqueous dispersion of seed particles (CATALOID SI-550, manufactured by Nisshajitsui Co., ltd., average particle diameter of 5nm, siO) ₂ Concentration 20 mass%) 3000g of pure water 17000g was added. Thereafter, 1 mass% sodium hydroxide was added to the dispersion, and the pH of the dispersion was adjusted to 10.0. Thereafter, the dispersion was heated to 80℃and S was added to the dispersion iO ₂ 1369g of sodium silicate aqueous solution having a concentration of 1.5 mass% as Al ₂ O ₃ 1369g of an aqueous sodium aluminate solution having a concentration of 0.5% by mass. Thereafter, the dispersion was washed by centrifugal sedimentation. Thus, a dispersion of the composite oxide particles (a-3) was obtained. At this time, the average particle diameter of the composite oxide particles (a-3) was 19nm.

The dispersion of the composite oxide particles (a-3) was heated to 85℃and added as SiO ₂ 2820g of sodium silicate aqueous solution having a concentration of 1.5 mass% as Al ₂ O ₃ 940g of sodium aluminate aqueous solution with a concentration of 0.5 mass percent. Thereafter, the dispersion was washed with an ultrafiltration membrane to a solid content concentration of 13 mass%. Thereafter, the dispersion was filtered through a capsule filter having a sieve size of 1. Mu.m. Thus, a dispersion of the composite oxide particles (b-3) was obtained. The composite oxide particles (b-3) had an average particle diameter of 22nm.

1125g of pure water was added to 500g of the dispersion of the composite oxide particles (b-3). Concentrated hydrochloric acid (concentration: 35.5 mass%) was added dropwise to the dispersion so that the pH of the dispersion became 1.0. The dissolved aluminum salt was separated by an ultrafiltration membrane while adding 10L of an aqueous hydrochloric acid solution having a pH of 3 and 5L of pure water to the dispersion, and the dispersion was washed. Thus, a dispersion of silica-based particles (C-3) having a concentration of 5% by mass was obtained.

Next, 52.5g of a silicic acid Solution (SiO) as a silica source was added to 100g of a dispersion of silica-based particles (C-3) ₂ 4.0 mass% of Na ₂ O concentration 12 ppm), and stirring was carried out thoroughly. Thereafter, the pH of the dispersion was adjusted to 9.5 by adding ammonia water. The dispersion was warmed from 25 ℃ to 360 ℃ over 335 minutes and held for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 420 minutes. Thereafter, the dispersion was again warmed from 25℃to 360℃over 335 minutes and maintained for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 420 minutes. Thereafter, the same operation was performed again (total 3 times). Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Next, anion exchange resin (DIAION S manufactured by Mitsubishi chemical Co., ltd.) was usedA20A) 200g, ion exchange was carried out for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P3) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P3) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P3) having a solid content of 20 mass% was prepared.

Next, 10g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P3), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P3) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (3) for Forming anti-reflection transparent coating film and substrate (3) having the coating film)

An anti-reflection transparent coating forming coating liquid (3) and a base material (3) having an anti-reflection transparent coating were produced in the same manner as in example 1 except that an acrylic resin (HITALOID 1007, hitachi chemical co.) was used in place of the MIBK dispersion of the particles (P3) and a 1/1 (mass ratio) mixed solvent of isopropyl alcohol and n-butyl alcohol was used in an amount of 1.07 g.

Example 4

< production of particles (P4) having voids inside a silica-containing outer shell >

To 1000g of a dispersion of silica-based particles (C-1), 128g of a silica sol (CATALOID SI-550 manufactured by Nissk catalyst chemical Co., ltd., average particle diameter of 5nm, solid content concentration of 20% by mass, na) was added ₂ O concentration 0.8 mass%) was thoroughly stirred. Subsequently, this dispersion was subjected to ion exchange for 1 hour using 200g of a cation exchange resin (DIAION SK1B manufactured by mitsubishi chemical corporation).

Then, the pH of the dispersion was adjusted to 10.0 by adding ammonia water. The dispersion was dried at 110℃for 6 hours to obtain a powder. The powder was warmed from 25 ℃ to 750 ℃ over 258 minutes and held for 5 hours. Thereafter, the powder was cooled to 50 ℃ over 375 minutes.

Thereafter, 500g of water was added to 50g of the powder, and then a 1% aqueous NaOH solution was added so that the pH became 10.2. Thereafter, zrO of 0.02mm was used ₂ And (3) carrying out dispersion treatment on the medium by using a bead mill.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P4) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P4) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P4) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P4), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P4) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (4) for Forming anti-reflection transparent coating film and substrate (4) having the coating film)

An antireflective transparent coating forming coating liquid (4) and a antireflective transparent coating-carrying substrate (4) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (P4) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Example 5

< production of particles (P5) having voids inside a silica-containing outer shell >

To 1000g of a dispersion of silica-based particles (C-1), 62.5g of a silica sol (CATALOID SI-550 manufactured by Nissk catalyst chemical Co., ltd., average particle diameter of 5nm, solid content concentration of 20% by mass, na) was added ₂ O concentration 0.8 mass%) was thoroughly stirred.

Then, the pH of the dispersion was adjusted to 10.5 by adding ammonia water. The dispersion was warmed from 25 ℃ to 200 ℃ over 583 minutes and held for 24 hours. Thereafter, the dispersion was cooled to 25℃over 4400 minutes. This operation was repeated 2 times.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P5) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P5) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P5) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P5), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P5) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (5) for Forming anti-reflection transparent coating film and substrate (5) with the coating film)

An antireflective transparent coating forming coating liquid (5) and a antireflective transparent coating-carrying substrate (5) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (P5) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Example 6

< production of particles (P6) having voids inside a silica-containing outer shell >

1000g of ethanol and 50g of aqueous ammonia were added to 1000g of the dispersion of silica particles (C-1), and the liquid temperature was adjusted to 35 ℃. 88.5g of tetraethoxysilane as a silica source was added to the dispersion, and the mixture was sufficiently stirred. Thereafter, the solvent was replaced with water using an ultrafiltration membrane.

Then, the pH of the dispersion was adjusted to 10.5 by adding ammonia water. The dispersion was warmed from 25 ℃ to 360 ℃ over 335 minutes and held for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 419 minutes. This operation was repeated 3 times.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P6) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P6) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P6) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P6), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P6) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (6) for Forming anti-reflection transparent coating film and substrate (6) having the coating film)

An antireflective transparent coating forming coating liquid (6) and a antireflective transparent coating-carrying substrate (6) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (P6) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Example 7

< production of particles (P7) having voids inside a silica-containing outer shell >

To 1000g of the dispersion of silica-based particles (C-1), aqueous ammonia was added to adjust the pH of the dispersion to 10.5. Thereafter, the dispersion was dried at 110℃for 6 hours, thereby obtaining a powder. The powder was warmed from 25 ℃ to 360 ℃ over 335 minutes and held for 24 hours. Thereafter, the powder was cooled to 25 ℃ over 420 minutes. This operation was repeated 3 times.

Thereafter, 500g of water was added to 50g of the powder, and then a 1% aqueous NaOH solution was added so that the pH became 10.2. Thereafter, zrO of 0.02mm was used ₂ The medium was subjected to dispersion treatment by a bead mill.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P7) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P7) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P7) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P7), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P7) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (7) for Forming anti-reflection transparent coating film and substrate (7) with the coating film)

An antireflective transparent coating forming coating liquid (7) and a antireflective transparent coating-carrying substrate (7) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (P7) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Example 8

< production of particles (P8) having voids inside a silica-containing outer shell >

To 1000g of a dispersion of silica particles (C-1), 128g of a high purity silica sol (LNA-2000 manufactured by Nippon catalyst chemical Co., ltd., average particle diameter of 23nm, solid content concentration of 12.6% by mass) as a silica source was added, and the mixture was sufficiently stirred.

Then, the pH of the dispersion was adjusted to 10.8 by adding ammonia water. The dispersion was dried at 110℃for 6 hours, thereby obtaining a powder. The powder was warmed from 25 ℃ to 360 ℃ over 335 minutes and held for 24 hours. Thereafter, the powder was cooled to 25 ℃ over 420 minutes. This operation was repeated 3 times.

Thereafter, ion exchange was performed with 400g of a cation exchange resin (DIAION SK1B manufactured by Mitsubishi chemical corporation) for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P8) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P8) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P8) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P8), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P8) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (8) for Forming anti-reflection transparent coating film and substrate (8) having the coating film)

An antireflective transparent coating forming coating liquid (8) and a antireflective transparent coating-carrying substrate (8) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (P8) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Example 9

< production of particle (P9) having voids inside a silica-containing outer shell >

Thereafter, the pH of the dispersion was adjusted to 10.8 by adding ammonia water. Thereafter, the dispersion was dried at 110℃for 6 hours, thereby obtaining a powder. The powder was warmed from 25 ℃ to 600 ℃ over 575 minutes and held for 5 hours. Thereafter, the powder was cooled to 50 ℃ over 550 minutes. This operation was repeated 3 times.

Thereafter, 500g of water was added to 50g of the powder, and then a 1% aqueous NaOH solution was added so that the pH became 10.0. Thereafter, zrO of 0.02mm was used ₂ The medium was subjected to dispersion treatment by a bead mill.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (P9) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (P9) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (P9) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (P9), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (P9) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (9) for Forming anti-reflection transparent coating film and substrate (9) having the coating film)

An antireflective transparent coating forming coating liquid (9) and a antireflective transparent coating-carrying substrate (9) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (P9) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Comparative example 1

< production of particles (R1) having voids inside a silica-containing outer shell >

Then, the pH of the dispersion was adjusted to 10.5 by adding ammonia water. The dispersion was warmed from 25 ℃ to 150 ℃ over 25 minutes and held for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 42 minutes.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (R1) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (R1) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (R1) having a solid content of 20% by mass was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (R1), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (R1) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (R1) for Forming anti-reflection transparent coating film and substrate (R1) having the coating film)

An anti-reflection transparent coating forming paint (R1) and a base material (R1) with an anti-reflection transparent coating were produced in the same manner as in example 1 except that the MIBK dispersion of the particles (R1) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Comparative example 2

< production of particles (R2) having voids inside a silica-containing outer shell >

1000g of ethanol and 50g of aqueous ammonia were added to 1000g of the dispersion of silica particles (C-1), and the liquid temperature was adjusted to 35 ℃. To this liquid, 57.9g of methyltrimethoxysilane as a silica source was added and stirred well. Thereafter, the solvent was replaced with water using an ultrafiltration membrane.

Then, the pH of the dispersion was adjusted to 10.5 by adding ammonia water. Thereafter, the dispersion was warmed from 25℃to 360℃over 335 minutes and maintained for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 419 minutes. This operation was repeated 3 times.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (R2) having voids inside the shell containing silica was obtained. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (R2) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (R2) having a solid content of 20 mass% was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (R2), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (R2) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (R2) for Forming anti-reflection transparent coating film and substrate (R2) having the coating film)

An antireflective transparent coating forming coating liquid (R2) and a antireflective transparent coating-carrying substrate (R2) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (R2) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

Comparative example 3

< production of particles (R3) having voids inside a silica-containing outer shell >

To 1000g of a dispersion of silica-based particles (C-1), 62.5g of silica particles (CATALOID SI-550 manufactured by Nissk catalyst chemical Co., ltd., average particle diameter of 5nm, solid content concentration of 20% by mass, na) as a silica source was added ₂ O concentration 08 mass%) was thoroughly stirred.

Next, 10.6g of a 10% aqueous NaOH solution was added to adjust the pH of the dispersion to 10.5. Thereafter, the dispersion was warmed from 25℃to 360℃over 335 minutes and maintained for 24 hours. Thereafter, the dispersion was cooled to 25 ℃ over 419 minutes. This operation was repeated 3 times.

Thereafter, 400g of cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was used to conduct ion exchange for 3 hours. Then, ion exchange was performed with 200g of an anion exchange resin (DIAION SA20A manufactured by Mitsubishi chemical corporation) for 3 hours. Thereafter, 200g of a cation exchange resin (DIAION SK1B, manufactured by Mitsubishi chemical corporation) was further used, and ion exchange was performed at 80℃for 3 hours, thereby performing washing. Thus, an aqueous dispersion of particles (R2) having voids inside the shell containing silica was obtained. However, the particles have a shape in which holes are formed in the shell and the hollow inside the shell is not closed by the shell. The solid content concentration of the dispersion was 20 mass%.

The solvent of the aqueous dispersion of the particles (R3) was replaced with methanol using an ultrafiltration membrane. Thus, a methanol dispersion of particles (R3) having a solid content of 20% by mass was prepared.

Next, 6g of 3-methacryloxypropyl trimethoxysilane (KBM-503 manufactured by Xinyue chemical Co., ltd.) was added to 100g of the methanol dispersion of the particles (R3), and the mixture was subjected to a heat treatment at 50℃for 6 hours. Thereafter, the solvent was replaced with MIBK using an evaporator. Thus, a MIBK dispersion of particles (R3) having a solid content of 20% by mass was obtained.

< preparation of coating liquid (R3) for Forming anti-reflection transparent coating film and substrate (R3) having the coating film)

An antireflective transparent coating forming coating liquid (R3) and a antireflective transparent coating-carrying substrate (R3) were produced in the same manner as in example 1, except that the MIBK dispersion of the particles (R3) was used instead of the MIBK dispersion of the particles (P1), and each characteristic was evaluated.

TABLE 1

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TABLE 2

TABLE 3

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Claims

1. A particle having a cavity inside a shell containing silica, characterized in that,

the average particle diameter D of the particles is 20-250 nm,

the diameter of the cavity is 0.5-0.9 times of the diameter of the particle,

Utilization of the particles N ₂ The pore volume of the adsorption method is less than 1.0cm ³ /g，

Refractive index n of the particles _a Is 1.08 to 1.34 percent,

the carbon content of the particles is 3.0 mass% or less,

the refractive index n of the shell is obtained by the following formula _S Is more than 1.38 of the total weight of the composite material,

[ mathematics 1]

n _a is the refractive index of the particles, n _p Is the refractive index of the cavity and is the refractive index of the cavity,

for the particles ²⁹ Area Q of peaks occurring at chemical shifts of-78 to-88 ppm in Si-NMR spectroscopy ₁ Area Q of peak appearing at chemical shift of-88 to-98 ppm ₂ In the chemical shift of-98-Area Q of peak at 108ppm ₃ Area Q of peak appearing at chemical shift of-108 to-117 ppm ₄ Ratio, i.e. Q ₁ /(Q ₁ +Q ₂ +Q ₃ +Q ₄ ) Essentially 0, ratio, Q ₂ /(Q ₁ +Q ₂ +Q ₃ +Q ₄ ) Substantially 0, and a ratio of Q ₃ /Q ₄ 0.01 to 0.7.

2. The particle of claim 1, wherein the particles are,

refractive index n of the shell of the particle _S 1.38 to 1.47.

3. The particle of claim 1, wherein the particles are,

in terms of the respective contents of the elements belonging to alkali metals of the particles, when the elements are expressed by oxides, relative to SiO ₂ Is 1ppm or less.

4. The particle of claim 1, wherein the particles are,

The particles have a content of Fe, ti, zn, pd, ag, mn, co, mo, sn, al and Zr of less than 0.1ppm, a content of Cu, ni and Cr of less than 1ppb, and a content of U and Th of less than 0.3ppb, respectively.

5. A coating liquid for forming a transparent coating film, characterized in that,

comprising the particles of claim 1, a matrix-forming ingredient, and an organic solvent.

6. A substrate with a transparent coating, comprising:

a substrate; and

a transparent coating film formed on the substrate, comprising the particles of claim 1 and a matrix.

7. A method for producing particles having voids inside a silica-containing shell, comprising:

a first step of, when the oxide of silicon is expressed as SiO ₂ Representing an oxide of an inorganic element other than the silicon which is alkali-soluble as MO _x In such a way that the molar ratio, MO _x /SiO ₂ A step of adding a solution containing a compound of silicon and an aqueous solution of a compound of the inorganic element to an alkaline aqueous solution at the same time so as to be 0.01 to 2, thereby preparing a dispersion of composite oxide particles a;

a second step, followed by the first step, of bringing the molar ratio, MO _x /SiO ₂ Adding an aqueous solution of a compound containing silicon and a compound of an inorganic element other than the alkali-soluble silicon to the dispersion of the composite oxide particles a at a molar ratio smaller than that of the first step, thereby preparing a dispersion of composite oxide particles b;

A third step of adding an acid to the dispersion of the composite oxide particles b to remove at least a part of elements other than silicon constituting the composite oxide particles b, thereby preparing a dispersion of silica-based particles; and

and a fourth step of heating the dispersion of silica particles to 360-750 ℃ at a heating rate of 0.3-3.0 ℃/min, and then cooling the dispersion at a cooling rate of 0.04-2.0 ℃/min to a temperature of less than 100 ℃.

8. The method for producing particles according to claim 7, wherein,

the fourth step includes repeating the heating and the cooling of the silica-based particle dispersion liquid a plurality of times.

9. The method for producing particles according to claim 7, wherein,

the step of adding at least one of an organosilicon compound represented by the following formula (2) and a partial hydrolysate thereof to the dispersion of silica-based particles is included between the third step and the fourth step,

R _n -SiX _4-n (2)

wherein R is an unsubstituted or substituted hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different from each other, and as a substituent, there are epoxy group, alkoxy group, (meth) acryloyloxy group, mercapto group, halogen atom, amino group and phenylamino group, X is an alkoxy group having 1 to 4 carbon atoms, hydroxyl group, halogen atom or hydrogen atom, and n is an integer of 0 to 3.