JP2001278637A - Low reflection glass article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single layer low reflection film which has low reflection coefficient, strong film strength with excellent abrasion resistance and moreover easy to remove the dirt. SOLUTION: The low reflection glass article formed on the glass substrate with the low reflection glass film composed of silica particles and binder is characterized in that the low reflection glass film contains the silica particles and the binder in a wt. ratio of 60:40-95:5 respectively, and the low reflection glass film is formed by coating the glass substrate with coating liquid which is prepared by mixing the raw material particles composed of at least one of non-aggregation silica grains with average grain diameter of 40-1000 nm and chain aggregation silica particles with an average primary diameter of 10-100 nm, with a hydrolyzable metal compound, water and solvent, then hydrolyze the hydrolyzable metal compound in the presence of the raw material particles, and thereafter heat treating is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to low-reflection glass articles such as glass windows for vehicles, architectural windows, show windows, displays, glass substrates for solar cells, glass plates for solar water heaters, and optical glass parts. is there.

[0002]

2. Description of the Related Art To reduce the visible light reflectance of a glass substrate,
It is widely known that the reflection is reduced by providing a film on a glass substrate. Laminate two or more layers on a glass plate,
As a method of realizing low reflection by utilizing the interference effect of light, for example, Japanese Patent Application Laid-Open No. 4-357134 discloses a method in which at least one surface of a transparent glass substrate is placed on the first surface from the glass surface side.
As a first layer, a thin film layer having a refractive index of n1 = 1.8 to 1.9 and a film thickness of 700 to 900 angstroms is coated. Then, a second layer having a refractive index of n2 = 1.
A thin film layer having a thickness of 4 to 1.5 and a thickness of 1100 to 1300 angstroms is coated and laminated. A reflection-reducing glass for vehicles having a two-layer film structure, wherein the reflectance of visible light on the thin-film-coated laminated surface is reduced by 4.5 to 6.5% is disclosed.
Japanese Patent Application Laid-Open No. 4-357135 proposes a glass provided with a low-reflection film composed of a three-layer film.

On the other hand, a method of reducing reflection by providing a single layer film on glass is disclosed in, for example, JP-A-63-1931.
The 01 discloses, on the surface of the glass body, Si was added in SiO ₂ fine particles (OR) ₄ (R is an alkyl group) and dried after coating an alcohol solution of, SiO ₂ fine particles and which on the body surface There is disclosed an antireflection film formed by depositing a SiO ₂ thin film for covering the substrate.

Japanese Patent Application Laid-Open No. Sho 62-17044 discloses that
A metal alcoholate such as tetraethoxysilane is mixed with colloidal silica having a particle size of 100 nm at a ratio of 1 mole of metal alcoholate to 1 mole of colloidal silica, and a mixed solution dissolved in an organic solvent such as alcohol is hydrolyzed. An antireflection film is disclosed in which a sol solution that has been partially condensed is coated on the surface of an optical element and then heat-treated.

Japanese Patent Application Laid-Open No. H11-292568 discloses a low visible light reflection coated with a low reflection film having a thickness of 110 to 250 nm containing fine silica particles in chain and 5 to 30% by weight of silica based on the fine particles. Glass is disclosed.

[0006] These low-reflection films formed of one low-refractive-index layer are disclosed in Optical Engineering Vol. 21 No. 6, (1982) Page.
As described in No. 1039, it is known that the wavelength dependence of reflectance is small due to the small dependence of the reflectance on the incident angle and the small wavelength dependence of the reflectance.

[0007]

The method of applying a coating film composed of two or more layers of a film to a glass substrate is a method capable of reliably reducing visible light, but satisfies interference conditions. As described above, the film thickness must be strictly defined, and the number of coating times must be two or more. Further, since the reflectance of the film having two or more layers is more dependent on the incident angle, the reflectance is not necessarily low except at the designed incident angle. In this respect, when a low-reflection film composed of a single layer having a low refractive index is applied to a glass substrate, the wavelength band of low reflection is wider as described above.

The antireflection films disclosed in the above-mentioned JP-A-62-17044 and JP-A-63-193101 do not provide sufficient antireflection performance. Further, the visible light low-reflection glass disclosed in Japanese Patent Application Laid-Open No. 11-292568 is a single-layer low-reflection film that achieves a low reflectance, but is evaluated such that the surface is rubbed as in a reciprocating wear test. However, there is a problem that the film strength is insufficient in a more severe abrasion resistance test such as a Tehber wear test. In addition, when oil stains adhere, there is a problem that the stains cannot be removed by wiping with a dry cloth or a compress and the reflectance increases.

The present invention is a single-layer, low-reflection film for visible light or infrared light which has a low reflectance, a high film strength satisfying a wear resistance test and the like, and is excellent in stain removal. The purpose is to provide.

[0010]

According to the present invention, there is provided a low-reflection glass article having a low-reflection film comprising silica fine particles and a binder formed on a glass substrate, wherein the low-reflection film comprises the silica fine particles and the binder in a weight ratio. 60: 40-
95: 5, and the low reflection film comprises: (1) at least one of non-aggregated silica fine particles having an average particle diameter of 40 to 1000 nm and chain-like aggregated silica fine particles having an average primary particle diameter of 10 to 100 nm. And (2) a hydrolyzable metal compound, (3) water and (4) a solvent, and hydrolyzing the hydrolyzable metal compound in the presence of the raw material fine particles. A low-reflection glass article characterized by being formed by coating the coated glass substrate on the glass substrate and performing a heat treatment.

The silica fine particles used in the present invention may be prepared by any method. For example, silica fine particles synthesized by reacting silicon alkoxide by a sol-gel method under a basic catalyst such as ammonia or sodium silicate may be used as a raw material. Colloidal silica, fumed silica synthesized in the gas phase, and the like. The structure of the obtained low-reflection film greatly changes depending on the particle size of the silica fine particles. If the particle size of the silica fine particles is too small, the size of the pores generated between the particles in the low reflection film becomes small, and the capillary force increases,
The adhered dirt becomes difficult to remove, and moisture and organic substances in the air gradually enter the pores, so that the reflectance increases with time. In addition, since the upper limit of the amount of the binder used for bonding the silica fine particles to each other and the silica fine particles and the glass substrate is set as described below, if the particle size of the silica fine particles is too small, the surface area of the fine particles is relatively large. As a result, the amount of the binder that reacts with the surface becomes insufficient, and as a result, the adhesion of the film becomes weak. On the other hand, if the silica fine particle diameter (primary particle diameter) is too small, the roughness of the surface of the formed film or the porosity inside the film (the film volume of the space between the silica fine particles where the binder is not buried). ) And the apparent refractive index increases. Therefore, (1) in order to easily remove dirt from the low reflection film, (2) to increase the film strength, and (3) to change the apparent refractive index by the refractive index ( In order to lower the value so as to be close to the square root value (about 1.22) of about 1.5), silica fine particles (refractive index of about 1.4) were used.
5) The average primary particle diameter is desirably 40 nm or more, and more desirably 50 nm or more. On the other hand, if the particle size of the silica fine particles is too large, the scattering of light becomes severe, and the adhesion to the glass substrate becomes weak. Applications where transparency is required, that is, applications where a low haze ratio, for example, a haze ratio of 1% or less, is desired, for example, vehicles,
In architectural windows, the average particle size of the silica fine particles is preferably 500 nm or less, more preferably 300 nm or less. The most preferred average particle size of the silica fine particles is 50 to 200 nm, and most preferably 70 to 160 nm.

On the other hand, in an application that does not require transparency and does not require very high film strength, for example, in a glass substrate for a solar cell, it is important to increase the transmittance by lowering the reflectance. Further, in order to increase the efficiency of absorbing sunlight in the silicon film provided close to the glass substrate, it is advantageous to increase the optical path length of sunlight incident on the silicon film in the silicon film. Light passing through the low-reflection film can be divided into straight transmitted light and diffuse transmitted light, and the haze ratio increases as the amount of diffuse transmitted light with respect to the amount of straight transmitted light increases. In comparison with a low-reflection film having the same total light transmittance (therefore, the same reflectance), the length of the optical path can be increased by increasing the amount of diffusely transmitted light in the light after passing through the low-reflection film. , That is, a low reflection film having a large haze ratio, for example, a low reflection film having a haze ratio of 10 to 80%. For the low reflection film having a large haze ratio, it is preferable to use silica fine particles having an average particle diameter of 100 nm to 1000 nm.

The average particle size of silica fine particles as raw material fine particles is actually measured by a transmission electron microscope of 10,000 to 50,000 times in a planar field of view. In this case, the diameter (average value of the major axis and the minor axis) of each primary particle) is actually measured, and defined as a number average value d of the number of fine particles (n = 100) according to the following equation. Therefore, this measured value is different from the particle diameter according to the BET method indicated by colloidal silica or the like. The sphericity of the silica fine particles is represented by a value obtained by averaging 100 ratios of the major axis length and the minor axis length of each fine particle. The standard deviation of the particle size, which represents the particle size distribution of the particles, is determined from the above diameter by the following formulas 2 and 3. In each equation, n = 100.

(Equation 1)

(Equation 2)

## EQU3 ## Standard deviation = (d + σ) / d (3)

When the sphericity of the silica fine particles is 1.0 to 1.2, a low-reflection film having a high degree of filling of the fine particles is formed, and the mechanical strength of the film is increased. More preferable sphericity is 1.0 to 1.1. In addition, when silica fine particles having a uniform particle diameter are used, the gap between the fine particles can be increased, so that the apparent refractive index of the film decreases and the reflectance can be lowered. Therefore, the standard deviation of the particle size representing the particle size distribution of the silica fine particles is preferably from 1.0 to 1.5, more preferably from 1.0 to 1.3, still more preferably from 1.0 to 1.1. is there.

As non-agglomerated silica fine particles having an average particle size of 40 to 1000 nm, commercially available products such as "Snowtex OL", "Snowtex YL" and "Snowtex ZL" manufactured by Nissan Chemical Co., Ltd. and "Sea Hostar" manufactured by Nippon Shokubai KE-
W10 "," Seahoster KE-W20 "," Seahoster KE-W30 "," Seahoster KE-W50 ",
"Sea Hoster KE-E70", "Sea Hoster KE-
E90 "and the like are preferable. As the silica fine particles, a silica fine particle dispersion liquid dispersed in a solvent is preferable because it is easy to handle. Examples of the dispersion medium include water, alcohols, cellosolves, and glycols, and silica fine particle dispersions dispersed in these dispersion media are commercially available. Further, silica fine powder may be used by dispersing it in these dispersion media.

When a plurality of fine particles are aggregated to form aggregated fine particles (secondary fine particles), the average particle size of the individual fine particles (primary fine particles) constituting the aggregated fine particles is defined as the average primary particle size. In the case of an aggregate of fine particles that are aggregated in a chain shape or a branched chain in which the fine particles are not branched (chain-like aggregated fine particles), the film becomes bulky because each fine particle is fixed while maintaining the aggregated state during film formation. The value of the roughness of the surface of the formed film and the porosity inside the film are larger than those of the non-agglomerated silica fine particles having the same average particle size as the average primary particle size of the chain aggregated fine particles. . Therefore, as the chain-like aggregated silica fine particles, those having an average primary particle size of less than 40 nm may be used.
Chain aggregated silica fine particles having an average primary particle diameter d of m are used. The chain aggregated silica fine particles have a particle size of 60 to 500.
It preferably has an average length (L) of nm and a ratio of the average length to the average primary particle size (L / d) of 3-20. Examples of the chain-like aggregated silica fine particles include “Snowtex OUP” and “Snowtex U” manufactured by Nissan Chemical Industries, Ltd.
P ".

The preparation of a coating solution for forming a low-reflection film is carried out by hydrolyzing a hydrolyzable metal compound in the presence of silica fine particles, whereby the mechanical strength of the resulting film is significantly improved. improves. In the case of the present invention in which the metal compound is hydrolyzed in the presence of silica fine particles, the condensation reaction between the product generated by the hydrolysis and the silanol present on the surface of the fine particles occurs almost simultaneously with the hydrolysis. The reactivity of the surface of the fine particles is improved by the condensation reaction with the binder component, and (2) the surface of the silica fine particles is coated with the binder as the condensation reaction further proceeds. It is used effectively to improve the performance. On the other hand, when the metal compound is hydrolyzed in the absence of fine particles, the binder component is polymerized by a condensation reaction between the hydrolysis products. When a coating solution is prepared by mixing the polymerized binder component and silica fine particles, (1) the condensation reaction between the binder component and the silica fine particles hardly occurs, so that the reactivity of the fine particle surface is poor. And (2) the surface of the silica fine particles is hardly coated with the binder. Therefore, when trying to increase the adhesion between glass and silica fine particles in the same manner as the former,
Requires more binder components.

Colloidal silica (average particle diameter 50 nm, "Snowtex OL" manufactured by Nissan Chemical Co., Ltd.) and tetraethoxysilane hydrolyzed in advance are mixed at a solid content ratio of 80: 2.
0, and a film B prepared using a coating solution prepared by further mixing a hydrolysis catalyst, water, and a solvent.
(Comparative Example), the above-mentioned colloidal silica and tetraethoxysilane were mixed at a solid content ratio of 80:20, respectively, and a hydrolysis catalyst, water, and a solvent were further mixed. The film A (the present invention) prepared using a coating solution prepared by hydrolyzing tetraethoxysilane in the presence of silica was compared with an electron microscope (SEM) photograph enlarged 100,000 times. The end faces (broken surfaces) of the films A and B are 3
SEM photographs viewed obliquely from above by 0 degrees are shown in FIGS. 1 and 2, respectively. Each of the two films is a film in which silica fine particles are laminated on a glass substrate. Note that 1
One white point is arranged, and the distance between the white points at both ends indicates 300 nm.

In FIG. 2 (film B), it is possible to confirm the presence of a film-like deposit having a considerable thickness covering the surface of several silica fine particles arranged next to the film surface. Since this film-like deposit is considered to be a binder component derived from tetraethoxysilane, in FIG. 2 (film B), the amount of binder that should work effectively for adhesion between the fine particles and between the fine particles and the substrate is as follows.
It appears to be reduced due to the above film deposits.
If the amount of tetraethoxysilane is increased to increase the amount of binder that must work effectively for adhesion,
The voids between the fine particles and the voids between the fine particles and the substrate surface are reduced, the apparent refractive index of the film is increased, and it is difficult to lower the reflectance.

In FIG. 1 (film A), such film-like deposits are hardly visible or exist, and all of the binder components uniformly cover the surface of each silica fine particle. It is presumed to be working effectively for adhesion between the substrate and the substrate. When the method for preparing the film A is performed, the content of the binder component can be reduced while maintaining the film strength, and the apparent refractive index of the film can be reduced. As a result, the film strength can be maintained and the reflectance of the film can be reduced. Can be achieved at the same time. According to the method of the film A, the same film strength can be obtained even when the amount of the binder is reduced by half, as compared with the case of the film B using a coating solution in which silica particles are mixed with a binder which has been hydrolyzed in advance. Here, the criterion of the film strength is JIS-R3212,
And in a Taber abrasion test specified in JIS-R3221, using a CS-10F rotating foil, 1000 rotations (JIS-R3222) or 500 rotations under a load of 500 g.
This was determined from the result of measuring the presence or absence of the film remaining at 200 rotations (JIS-R3221) with a g load and the haze ratio before and after the Taber abrasion test.

The binder in the present invention comprises a metal oxide, and at least one metal oxide selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide and tantalum oxide is preferably used. . The weight ratio between the silica fine particles forming the low reflection film and the binder is in the range of 60:40 to 95: 5.
If the amount of the binder is larger than this range, the fine particles are buried in the binder and the roughness value of the fine particles or the porosity in the film becomes small, so that the antireflection effect becomes small. If the amount of the binder is smaller than this, the adhesion between the fine particles and the glass substrate and between the fine particles is reduced, and the mechanical strength of the film is reduced. Considering the balance between the reflectance and the film strength, the weight ratio of the silica fine particles to the binder is more preferably 65:35 to 85:15. The binder is preferably coated on the entire surface of the silica fine particles, and the coating thickness is preferably 1 to 100 nm and 2 to 9% of the average particle size of the silica fine particles.

As the hydrolyzable metal compound serving as a binder raw material, metal alkoxides of Si, Al, Ti, Zr, and Ta are preferable from the viewpoint of the strength and chemical stability of the film. Among these metal alkoxides, silicon tetraalkoxide, aluminum trialkoxide, titanium tetraalkoxide and zirconium tetraalkoxide, particularly methoxide, ethoxide, propoxide and butoxide are preferably used. In particular, in a film in which the content of the binder component is large, the refractive index of the binder component affects the reflectance, so that a silicon alkoxide having a small refractive index, particularly silicon tetraalkoxide or an oligomer thereof is most preferable. Also,
As the binder component, a mixture of a plurality of these metal alkoxides may be used. Other than metal alkoxides, there is no limitation as long as a reaction product of M (OH) _n can be obtained by hydrolysis. For example, metal halides,
Metal compounds having an isocyanate group, an acyloxy group, an aminoxy group and the like are exemplified. Further, for example, a compound represented by R ¹ _n M (OR ² ) _4-n which is a kind of silicon alkoxide (M is a silicon atom, R ¹ is an alkyl group, an amino group, an epoxy group, a phenyl group, a methacryloxy group, etc. An organic functional group, R ² is, for example, an alkyl group and n is an integer of 1 to 3) can also be used as a binder raw material. R ¹ _n M above
When the compound represented by (OR ² ) _4-n is used, an organic residue remains on the gel film after coating. The small pore size increases the capillary force, making it difficult to remove the adhered dirt, causing problems such as dirt and water entering the micropores and causing a change in reflectance over time, and also causes a problem with the film. The compound represented by R ¹ _nM (OR ² ) _4-n is preferably not used in a large amount because the strength is also weakened. Within

The haze ratio of a glass article coated with a low-reflection film is the sum of the haze ratio of the glass substrate itself and the haze ratio of the low-reflection film. A small glass plate having a haze ratio of 0.1% or less, for example, is used. Therefore, the haze ratio of the low reflection glass article of the present invention is substantially equal to the haze ratio of the low reflection film. It is preferable that the haze ratio of the low reflection film is adjusted to an optimum range that varies depending on the application. For example, in an automobile window, a low haze ratio is preferable from the viewpoint of safety, and the haze ratio of the low reflection glass article is 1% or less.
More preferably, it is 0.5% or less.

On the other hand, in a glass plate for a solar cell, in order to make effective use of the energy of sunlight, a film of polycrystalline silicon, single crystal silicon, amorphous silicon or the like provided in close proximity to the glass plate is subjected to multiple reflection. If the optical path length is increased, the incident light can be used efficiently, so that the conversion efficiency is improved. For this purpose, as described above, a low-reflection film having a large amount of diffused transmitted light, that is, a low-reflection film having a large haze ratio is best.

A glass plate for a solar cell that reduces the reflectance and diffuses and transmits light is effective in increasing the total light transmittance (total transmittance of the linearly transmitted light and the diffusely transmitted light) and increasing the optical path length in silicon. The effect is remarkable when the haze ratio is 10% or more. When the haze ratio exceeds 80%, the effect of lowering the reflectance (increase of the transmittance) is almost eliminated. Therefore, the glass plate for a solar cell of the present invention is 10 to 80%
It is preferable to have a haze ratio of However, the haze ratio exceeds 80% when an increase in the amount of diffused light is desired rather than a high total light transmittance or when appearance such as reduction of specular reflection light (prevention of reflection image reflection) is important. You may. When a large film strength is required, the haze ratio of the glass plate for a solar cell is a standard of 30% or less. As a method for achieving both the antireflection performance and the light diffusion / transmission property, two types of fine particles having different average particle sizes, that is, (1) an average particle size of 40, are used as the non-aggregated silica fine particles used in the coating liquid for a low reflection film. 70-95% by weight of first non-agglomerated silica microparticles of -200 nm, and (2) 200
second non-agglomerated silica fine particles having an average particle diameter of not less than 3000 nm and not more than 3000 nm and at least 100 nm larger than the average particle diameter of the first non-agglomerated silica fine particles.
0% by weight may be used. In the low reflection film obtained by using the non-agglomerated silica fine particles, the occupied area of the fine particles having an average particle size of 40 nm to 200 nm as viewed from above the film is 30 to 90%, and the average particle size is 200 nm to 200 nm.
The occupied area of the 3000 nm fine particles is 50% or less, more preferably 1% or more and 30% or less. Here, the occupied area refers to an area occupied and occupied by fine particles per unit area of the film when the glass surface is viewed from the vertical direction. When the fine particles are overlapped, the occupied area is obtained from the area of the uppermost fine particles. Not all surface portions on the substrate need be occupied by particulates. The former portion occupied by the fine particles provides antireflection performance, and the latter portion occupies the fine particle scattered light. In this way, the haze can be increased up to 30% while keeping the reflectance low.

When non-agglomerated fine particles having a uniform particle size are arranged in a row on a glass substrate, the relationship between the particle size of the fine particles and the haze ratio is shown assuming that the content of the fine particles is 80% by weight and the binder amount is 20% by weight. The haze ratio is about 10% for a film formed of fine particles having a particle size of only 200 nm, about 20% for only 300 nm, about 55% for only 500 nm, and 70% for fine particles having a particle size of 700 nm. Particle size 900
In the case of fine particles of nm or more, the haze ratio exceeds 70%.

The lower the reflection effect, the higher the safety for automobiles, and the more energy available for the solar cell substrate, the lower the reflectance is preferable, and the reflectance from the film surface is 2%. %, More preferably 1% or less, further preferably 0.7% or less.

The structure of the low-reflection film is such that the silica fine particles having a surface coated with a binder (hereinafter sometimes simply referred to as fine particles) have a shape such that they cover almost the entire surface of the glass substrate. Best for reducing reflectivity. When fine particles of exactly the same particle size are closely packed and spread over a glass substrate, the area occupied by the fine particles as viewed from above is theoretically about 90%. In the low reflection film in which only one layer of fine particles is formed, the occupied area is preferably 50% or more, more preferably 70% or more, for obtaining low reflection performance. If the occupied area is less than 50%, since the surface of the glass substrate is exposed, the reflection due to the difference in the refractive index between the glass and the air appears strongly, so that the reflection cannot be reduced. The structure may be a low-reflection film in which the fine particles are arranged only on the upper surface of the glass, or a structure in which the fine particles are stacked in multiple stages. In either a single layer or a multi-layered structure, pores corresponding to the diameter of the fine particles are formed in the gap between the glass substrate and the fine particles or in the gap between the fine particles, and the pores reduce the apparent refractive index. It is effective for Observing the film with an electron microscope from directly above the film, the fine particles lined up in a plane on the outermost surface of the film, and located below the uppermost fine particles,
The total number of fine particles that can be observed even slightly from the gap between the fine particles on the outermost surface is 1 μm × when non-agglomerated silica fine particles having an average particle size of 40 to 500 nm are used as raw material fine particles.
It is preferable that 30 to 3000 particles are present in a 1 μm square area, and these fine particles have an average particle size of 40 to 500 nm. The total number is more preferably 100 or more and 1
000 or less. In addition, 100 to 100
When non-agglomerated silica fine particles having an average particle size of 1000 nm are used, the total number of the fine particles is 10 μm × 10 μm.
The number of particles is preferably 10 to 50,000 in the square area of m, and these fine particles preferably have an average particle diameter of 100 to 1000 nm. The total number is more preferably 20 or more and 25,000 or less. The density of the fine particles depends on the size of the fine particles. The larger the fine particle diameter, the smaller the number, and the smaller the fine particle diameter, the larger the number. Rather than the fine particles being carried alone on the glass substrate, a structure in which the fine particles exist densely and come into contact with each other via a binder to increase the film strength is desirable. For example, when the average particle size of the fine particles is Dnm, the number of fine particles observed by an electron microscope from directly above a 10 μm × 10 μm square film is 5,000.
It is preferably from 000 / D ^{2 to} 10,000,000 / D ² .

The average thickness of the low reflection film of the present invention is defined below. A photograph is prepared by observing the cross section of the film at a magnification of 50,000 with an electron microscope. Electron micrograph 10
cm (substantially 2 μm), arbitrarily selected, twelve places in order from the largest convex part of the film, and heights from the base surface of ten tenth convex parts from third to twelfth counted from the largest. Is the average thickness. If 12 convex portions cannot be selected because the diameter of the fine particles to be used is large or fine particles are sparse, the magnification of the electron microscope can be sequentially reduced from 50,000 times to select 12 convex portions. Thus, the average thickness is determined by the above method. A film having an average thickness in the range of 90 nm or more and 180 nm or less reduces the reflectance in the visible light region most. The value of the physical thickness d defined by the optical thickness (nd) is smaller than the average thickness, and the physical thickness d corresponding to the average thickness of 90 to 180 nm is 80 to 140 nm. This is glass /
This is because the interference condition of the reflected light between the film interface and the film / air interface is satisfied. This interference condition is 2n-1 of the thickness described above.
Therefore, even if the thickness is three times or more, the reflectance is reduced, but the strength of the film is undesirably reduced.

On the other hand, visible light (400 to 780 nm) and infrared light (780 nm)
Considering a region extending over both of the low-reflection films, the average thickness of the low-reflection film is preferably 90 nm or more and 350 nm or less. This is because the physical thickness d is 80 nm or more.
It corresponds to 300 nm.

Particularly, in a windshield for an automobile,
Since the mounting angle (the inclination angle from the vertical plane) is about 60 degrees, a film design according to the method of use is required.
The surface reflectance (excluding back reflection) of soda lime glass with a refractive index of 1.52 is 4.2% at an incident angle of 12 degrees, but an incident angle of 60 degrees, which is a windshield attached to an automobile. , Which corresponds to the incident angle of incident light from the horizontal direction, reaches 9% or more. A low-reflection film composed of fine particles and a binder is approximated as a single-layer film having an average refractive index including voids, but the interference between the reflected light at the glass-low-reflection film interface and the reflected light at the low-reflection film-air interface. By utilizing the action to shift the optical path difference between the reflected lights by half a wavelength, low reflection performance is realized. When the angle of incidence on the glass with the low reflection film is increased, the optical path difference moves in the direction of decreasing, so that it is necessary to increase the optical thickness (nd) of the low reflection film compared to the reflection at normal incidence. . In order to reduce the reflectance at 60 degrees incidence, it is preferable to design the optical thickness to be about 140 nm to 250 nm. The surface reflectance at an incident angle of 60 degrees largely depends on the apparent refractive index and optical thickness of the low reflection film, but is 6%.
Or less, preferably 5% or less, more preferably 4% or less.

In the present invention, the coating liquid for the low reflection film is prepared by mixing silica fine particles, a hydrolyzable metal compound, a hydrolysis catalyst, water and a solvent.
Hydrolyze. For example, the reaction is performed by stirring at room temperature for 1 hour to 24 hours, or at a temperature higher than room temperature, for example, 40 ° C.
The reaction can be carried out by stirring at 80 ° C. for 10 to 50 minutes. The obtained coating liquid may be subsequently diluted with an appropriate solvent according to the coating method.

As the hydrolysis catalyst, an acid catalyst is most effective, and examples thereof include mineral acids such as hydrochloric acid and nitric acid, and acetic acid. In the case of an acid catalyst, the condensation polymerization rate is lower than that of a hydrolysis reaction of a hydrolyzable metal compound such as a metal alkoxide, and the hydrolysis reaction product M (OH) _n
Is generated in a large amount, which is effective because it effectively acts as a binder. With a basic catalyst, the condensation polymerization rate is higher than the rate of the hydrolysis reaction, so the metal alkoxide is used as a reaction product in the form of fine particles or used to grow the particle size of the silica particles originally present, As a result, the effect of the metal alkoxide as a binder is reduced. The content of the catalyst is preferably 0.001 to 4 in a molar ratio to the metal compound serving as the binder.

The amount of water required for the hydrolysis of the metal compound is preferably 0.1 to 100 in a molar ratio to the metal compound. When the amount of water added is less than 0.1 in molar ratio, the promotion of hydrolysis of the metal compound is not sufficient, and
If it is more than 0, the stability of the liquid tends to decrease, which is not preferable.

When the above-mentioned chloro group-containing compound is used as the metal compound, it is not always necessary to add a catalyst. The chloro group-containing compound can undergo a hydrolysis reaction without a catalyst. However, it does not matter if an acid is additionally added.

The solvent may be basically any solvent as long as it substantially dissolves the metal compound, but may be any of alcohols such as methanol, ethanol, propanol and butanol, cellosolves such as ethyl cellosolve, butyl cellosolve and propyl cellosolve, and ethylene. Glycols such as glycol, propylene glycol and hexylene glycol are most preferred. If the concentration of the metal compound dissolved in the solvent is too high, the amount of the silica fine particles to be dispersed also depends on the concentration, but it is not possible to generate a sufficient space between the fine particles in the film. And preferably a concentration of 1 to 20% by weight.
Then, in the coating solution, the amount of the silica fine particles and the amount of the metal compound (metal oxides such as SiO ₂ , Al ₂ O ₃ ,
The proportion of each conversion) on _{TiO 2, ZrO 2, Ta 2} O 5 , in weight ratio, 60: 40-95: 5, and more preferably 65: 35 to 85: a 15.

The preferred raw material mixing ratio of the coating liquid in the present invention is as shown in Table 1 below.

[0038]

[Table 1] 金属 Hydrolyzable metal compounds (in terms of metal oxides) 100 parts by weight, raw material fine particles comprising at least one of non-agglomerated silica fine particles having an average particle diameter of 40 to 1000 nm and chain aggregated silica fine particles having an average primary particle diameter of 10 to 100 nm, 150 to 1900 parts by weight, water 50 to 10,000 parts by weight Acid catalyst 0 to 200 parts by weight, preferably 0.01 to 200 parts by weight, solvent 1000 to 500,000 parts by weight ─────────

The coating solution is applied to a glass substrate and heated to cause a dehydration-condensation reaction of the hydrolyzate of the metal compound and vaporization / burning of volatile components to form a low-reflection film on the glass substrate. .

The coating method is not particularly limited as long as a known technique can be used. Examples of the method include a method using an apparatus such as a spin coater, a roll coater, a spray coater, a curtain coater, a dipping and pulling method (dip coating method), and a flowing method. Various printing methods such as a coating method (flow coating method) and screen printing, gravure printing, and curved surface printing are used. Glycols are effective solvents especially in coating methods that require a high boiling point solvent, such as flexographic printing and gravure printing, for unknown reasons, but glycols suppress aggregation of fine particles and haze. This is a convenient solvent for producing a low-reflection film having a low density. The weight ratio of glycol contained in the coating liquid is preferably 5% or more and 80% or less.

Depending on the glass substrate, it may not be possible to apply the coating solution uniformly by repelling the coating solution.
This can be improved by cleaning or modifying the surface of the substrate. As a method of cleaning or surface modification, alcohol, acetone, degreasing cleaning with an organic solvent such as hexane, cleaning with an alkali or acid, a method of polishing the surface with an abrasive,
Examples include ultrasonic cleaning, ultraviolet irradiation treatment, ultraviolet ozone treatment, and plasma treatment.

The heat treatment after coating is an effective method for increasing the adhesion between the film composed of the silica fine particles and the binder and the glass substrate. The processing temperature is 200 ° C. or higher, preferably 400 ° C. or higher, and more preferably 600 ° C. or higher and 1800 ° C. or lower at the highest temperature. At a temperature of 200 ° C. or higher, the solvent component of the coating liquid evaporates, the gelation of the film proceeds, and an adhesive force is generated. Further, at 400 ° C. or higher, the organic components remaining in the film are almost completely eliminated by combustion. 600 ° C
Above, the condensation reaction of the remaining unreacted silanol groups and the hydrolyzable groups of the hydrolyzate of the metal compound is almost completed, and the film is densified, and the film strength is further improved. Heating time is 5
Seconds to 5 hours are preferred, and 30 seconds to 1 hour are more preferred.

The low reflection film of the present invention is formed on one or both surfaces of a glass substrate. Both surfaces of the glass plate are air,
When the film is used facing a medium having a refractive index close to 1 such as gas, a higher antireflection effect can be obtained by forming this film on both surfaces of the glass substrate. However, when one surface of the glass substrate is used to face a medium having a refractive index close to the refractive index of the glass substrate, for example, two glass plates are bonded between the two via a transparent resin layer such as polyvinyl butyral. In the laminated glass, the visible light reflection at the interface between the glass plate and the transparent resin layer can be neglected, so that the low reflection film is not formed on the surface of the glass plate facing the transparent resin layer. It is sufficient to form it only on the outer surface of the glass plate.

When the low-reflection glass article of the present invention is used, for example, for automobiles, the glass plate coated with the low-reflection film may be further coated with a water-repellent coating or an anti-fog coating on its surface. it can. By coating with a water-repellent film, water-repellent performance can be obtained, and when dirt adheres, the dirt-removing property can be further improved. The water repellency obtained by coating the water repellent film on the low reflection film of the present invention shows superior water repellency as compared with a case where an untreated glass plate surface is treated with the same water repellent. In addition, by coating the antifogging film, antifogging performance can be obtained, and when dirt adheres, the dirt removability can be improved. Glass plate (Laminated glass plate may be used)
Both surfaces may be coated with a low-reflection film, and a water-repellent film may be coated thereon.A low-reflection film may be coated on one surface of the glass plate, and both the low-reflection film and the untreated glass surface, or a combination thereof. A water-repellent coating may be coated on one of them.

Similarly, both surfaces of a glass plate (which may be a laminated glass plate) may be coated with a low-reflection film, and an antifogging film may be coated thereon, or one side of a glass plate (which may be a laminated glass plate). The surface may be coated with a low-reflection film, and the anti-fogging film may be coated on both or one of the low-reflection film and the untreated glass surface.

Further, both surfaces of a glass plate (which may be a laminated glass plate) are coated with a low-reflection film, the surface of one of the films (inside the vehicle, the indoor side) is coated with an anti-fog coating, and the other surface is coated. It is preferable that a water-repellent coating is coated on the surface of the layer film (outside of the car, outside), and a low-reflection film is formed only on one surface (inside of the car, indoor) of a glass plate (or a laminated glass plate). And the surface of the film is coated with an anti-fogging film, and the other surface of the glass substrate (outside the car, outside)
It is preferable that a water-repellent film is coated thereon. Even if the anti-fogging film and the water repellent film are coated on the low reflection film, the reflectance is hardly changed and the low reflectance is maintained.

As the transparent glass substrate in the present invention,
A transparent glass article having a refractive index of 1.47 to 1.53, such as a soda-lime silicate glass, a borosilicate glass, or an aluminosilicate glass;
A glass plate colored green, bronze, or the like, or a glass plate having a performance of blocking ultraviolet rays, heat rays, or the like, or a glass material having a shape other than the plate shape having the various compositions, coloring, and blocking performance. A transparent glass substrate or the like may be used, and a glass plate having a thickness of 0.2 mm to 5.0 mm, a visible light transmittance Ya of 70% or more, and a haze ratio of 0.1% or less is preferably used. When used for a glass plate for a solar cell such as a front glass plate for a solar cell panel or a glass plate for a solar cell substrate, the thickness is 0.2 mm to 5.0 m.
In m, a glass plate substrate having a visible light transmittance Ya of 85% or more, particularly preferably 90% or more, and a haze ratio of 0.1% or less is preferably used.

The low-reflection glass article of the present invention can be used for automobiles, which are particularly required to have transparency / visibility and prevention of reflection of reflected images in vehicles.
Window glass for vehicles such as railways; front windows for architectural windows, show windows, image display devices, or optical glass parts; front glass plates for solar water heaters; front glass plates for solar cell panels; glass plates for solar cell substrates Such as a glass plate for a solar cell.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below, but the present invention is not limited thereto. In the following Examples and Comparative Examples, the optical characteristics were JI
The reflectance and the reflection color tone were measured by S-R3106 as described below, and the surface roughness, abrasion resistance and stain resistance were measured as described below.

Film surface reflectance 1: The reflectance when standard light A specified in JIS-Z8720 is incident from the film surface side at an incident angle of 12 degrees is measured according to JIS R 3106, and The reflectance does not include the reflection on the back surface. The term “reflectance” or “film surface reflectance” simply refers to this film surface reflectance 1. Film surface reflectance 2: The reflectance when the light is incident from the film surface side at an incident angle of 12 degrees is measured, and is the reflectance including the reflection on the back surface of the glass. Total light transmittance and haze ratio: Total light transmittance using an integrating sphere type light transmittance measuring device (“HGM-2DP”, manufactured by Suga Test Instruments Co., Ltd., using a C light source, light incident from the film surface side). And the haze (haze rate) are measured in accordance with JIS K7105-1981.
It was measured by the haze measurement method described in (Test Method for Optical Properties of Plastics). Reflection color tone (a, b): A C light source is used to make the light incident on the film surface at an incident angle of 12 degrees, and the reflection color of the reflection light including the reflection light on the back surface of the glass is measured according to JIS Z 8729 and obtained by the color coordinates of the hunter. Value. Taber abrasion 1: According to the provisions of JIS-R3221,
Using a rotating foil of CS-10F, the presence or absence of the film after 200 rotations with a load of 500 g was examined. When the film was left on the entire surface, it was evaluated as 、, when it was partially left, it was evaluated as △, and when there was no film, ×. The increase in haze after Taber abrasion is shown in parentheses.
(“[Haze rate (%) after Taber abrasion test] − [haze rate (%) before Taber abrasion test]]” is shown. Taber abrasion 2: The same as Taber abrasion 1 except that the condition was evaluated after 1000 rotations with a load of 500 g. Robustness: Dry flannel cloth traverse tester (“HEIDON-18” manufactured by Shinto Kagaku Co., Ltd., 10 with a load of 500 g / cm ²⁾
(00 reciprocations) was evaluated by the haze ratio and total light transmittance before and after the test. Note that the above Taber abrasion 1, Taber abrasion 2, and robustness are all measures for evaluating the abrasion resistance of the film, and the most severe abrasion test is Taber abrasion 2, followed by Taber abrasion 1. , In the order of robustness. Taber abrasion 1 and Taber abrasion 2 are suitable for evaluation of abrasion resistance when used, for example, as windows for automobiles and buildings, and the robustness is suitable for evaluation of abrasion resistance of a glass plate for a solar cell. Surface roughness (Ra): The surface roughness Ra was measured with an atomic force microscope (AFM, Seiko Denshi “SPI3700”) in a measurement range of 2 μm × 2 μm. Stain removal: Fingerprints were applied by pressing the thumbs of the hands against the glass-coated surface, and breath was wiped off with tissue paper. Exhalation was again performed to observe the remaining state of the fingerprint, and it was determined whether or not the reflectance changed before and after fingerprinting and wiping with tissue paper as follows. Judgment ：: Fingerprint shape is not visible, reflectance does not change before and after wiping △: Fingerprint shape is visible, but reflectance does not change before and after wiping ×: Fingerprint shape is visible and reflectance changes before and after wiping

Example 1 Silica fine particle dispersion (average particle diameter 50 nm, standard deviation of particle diameter 1.4, average value of ratio of long axis length to short axis length 1.1, solid content 20%, Nissan) While stirring 40 g of chemical “Snowtex OL”, 52.1 g of ethyl cellosolve, 1 g of concentrated hydrochloric acid, and 6.9 g of tetraethoxysilane were sequentially added thereto, and the mixture was stirred for 120 minutes and left to react for 12 hours. Was. 4 g of this sol was diluted with 6 g of ethyl cellosolve to prepare a coating solution having a solid content of 4%.

A 3.4 mm thick float glass substrate having a soda-lime silicate glass composition and colored green (refractive index = 1.52, visible light transmittance Ya = 81.3%, total light transmittance = 81) 0.1%, solar radiation transmittance Tg = 60.8%,
UV transmittance Tuv (iso) = 26.9%, visible light reflectance 7.4%, transmission color L of Hunter color system L = 90.7, a = −
4.5, b = 0.8, reflection color L = 27.3, a = -1.
3, b = -0.4) on one surface by spin coating using the above coating solution, and further placed in an electric furnace at 700 ° C. for 2 minutes to obtain an average film thickness of 128 nm.
The low reflection glass plate coated with the low reflection film was obtained. The maximum temperature reached by heating in the electric furnace was 630 ° C. A photograph of an electron microscope (magnified 100,000 times) in which the end surface (broken surface) of the film of the obtained glass plate with a film is viewed obliquely upward by 30 degrees from the film plane direction is the same as that in FIG. 1 described above.

Example 2 The average thickness of the film in Example 1 was set to 1
The same procedure was performed except that the thickness was changed to 05 nm. The average film thickness was adjusted so as to satisfy the condition that the visible light reflectance was minimized. The average film thickness of the following Examples 3 to 5 and Comparative Examples 1 to 7 was similarly adjusted.

Example 3 Silica fine particle dispersion (average particle diameter 70 nm, standard deviation of particle diameter 1.3, average value of ratio of major axis length to minor axis length 1.1, solid content 40%, Nissan) With stirring 21.3 g of chemical "Snowtex YL", 21.3 g of water, 51.3 g of ethyl cellosolve, 1 g of concentrated hydrochloric acid, and 5.2 g of tetraethoxysilane were sequentially added thereto and reacted for about 4 hours. Ethyl cellosolve 6 is added to 4 g of this sol.
g was added to obtain a coating solution. A glass substrate having the same composition as the substrate used in Example 1 and having a thickness of 2.0 mm (visible light transmittance Ya = 85.3%, total light transmittance = 85.4%,
Solar transmittance Tg = 71.0%, UV transmittance Tuviso =
61.6%, visible light reflectance 7.6%, transmission color a = −2.9, b = 0.4, reflection color a = −0.
1, b = -0.8) and subjected to the same heat treatment as in Example 1. The average thickness of the obtained film was 123 nm. End face (fracture surface) of the obtained glass plate with film
FIG. 3 shows a photograph of an electron microscope (magnified 100,000 times) in which the portion was viewed obliquely upward by 30 degrees from the film plane direction.

Example 4 Silica Fine Particle Dispersion (Average Particle Size: 110 nm, Standard Deviation of Particle Size: 1.1, Average of Ratio of Long Axis Length to Short Axis Length: 1.03, Solid Content: 15%, Japan 40.3 g of ethanol, 8.7 g of tetraethoxysilane, and 1.0 g of concentrated nitric acid were sequentially added to 50.0 g of a catalyst “Seahoster KE-W10” while stirring, and reacted for 3 hours. The solid content was adjusted to 3%, and the film was formed by spin coating to form an uncolored transparent (clear) float glass substrate having a soda-lime silicate glass composition and a thickness of 2.8 mm (refractive index = 1.52, visible light transmittance Ya). = 89.9%, total light transmittance = 89.7%, solar transmittance Tg = 84.3
%, UV transmittance Tuviso = 61.3%, visible light reflectance 8.0%, transmission color L of Hunter color system L = 94.9, a = −
1.0, b = 0.2, reflection color L = 28.3, a = -0.
4, b = -0.6). The coated glass was placed in an electric furnace heated to 500 ° C. for 30 minutes to perform a heat treatment. The average thickness of the obtained film is 163n.
m. FIG. 4 shows a photograph of an electron microscope (enlarged 100,000 times) in which the end surface (fracture surface) of the film of the obtained glass plate with a film is viewed obliquely upward by 30 degrees from the film plane direction.

Example 5 Chain-Aggregated Silica Fine Particle Dispersion (Average Primary Particle Size 25 nm, Average Length 100 nm, Solid Content 15%, Nissan Chemical's “Snowtex OUP”) 5
3.3 g, ethanol 38.8 g, 3 mol / L hydrochloric acid 1
g, and 6.9 g of tetraethoxysilane were mixed and reacted for 12 hours to prepare a coating solution. The same glass substrate as in Example 1 was spin-coated on one surface using the above-mentioned coating solution, and further placed in an electric furnace at 600 ° C. for 10 minutes to form a low-reflection film having an average film thickness of 120 nm. A reflective glass plate was obtained. The maximum temperature reached by heating in the electric furnace was 590 ° C.

In Examples 1 to 5, the form of the silica fine particles (discrimination between non-agglomerated fine particles and chain-like agglomerated fine particles, and when two types of fine particles are mixed is referred to as “mixing”), Certain average particle size (however, the average primary particle size for chain-like agglomerated silica particles), binder content (% by weight), silica fine particle content (% by weight), final film thickness (average film thickness), coating liquid In the preparation of
The presence or absence of hydrolysis of silicon alkoxide in the presence of silica fine particles (the presence or absence of “hydrolysis in the presence of silica fine particles”).
The number of fine particles (fine particle density) on the film surface with a square area of 1 μm, and the type of glass substrate (color and thickness (mm))
And the film surface reflectivity 1 of the obtained low reflection glass plate,
Table 2 shows the evaluation results of the film surface reflectance 2, haze ratio (%), reflection color tone a / b, Taber abrasion 1, Taber abrasion 2, surface roughness Ra (nm), and stain removal. The value of the reflected light saturation [(a ² + b ² ) ^1/2 ] calculated from the reflected color tone was 4 or less in each of the examples.

[0058]

[Table 2] ─────────────────────────────────── Example 1 Example 2 Example 3 Example 4 Example 5 ─────────────────────────────────── Silica fine particles Non-aggregation Same as left Same as left Same as left Chain aggregation Average Particle size 50 nm 50 nm 70 nm 110 nm 25 nm binder amount 20% 20% 15% 25% 20% silica fine particle amount 80% 80% 85% 75% 80% average thickness 128 nm 105 nm 123 nm 163 nm 120 nm hydrolysis in the presence of yes yes yes yes yes fine particles Density 800 pieces 750 pieces 500 pieces 180 pieces 2700 pieces (1 μm square) Substrate (color, thickness mm) Clean 3.4 Clean 3.4 Clean 2.0 Clear 2.8 Clean 3.4 −−−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−− Film reflectance 1 1.3% 0.9% 0.6% 0.3% 0.4% Film reflectance 2 4.7% 4.3% 4.0% 4.3% 3.6% Haze ゛Rate (%) 0.1 0.2 0.1 0.2 0.1 Reflected color tone a / b -1.3 / -3.5 -1.2 / -1.1 -1.0 / -1.9 -1.5 / 2.1 -1.1 / -1.4 The wear of the taper 1 ○ (1.3) ○ (1.2) ○ (1.0) ○ (1.3) ○ (1.9) The wear of the taper 2 ○ (1.8) ○ (1.6) ○ (1.5) ○ (1.5) ○ (2.4) Ra (nm) 10.1 7.8 12.5 19.6 5.8 Stain removal ○ ○ ○ ○ ○ ────────────────── ─────────────────

In the low reflection glasses of Examples 1 to 5, the film surface reflectance, particularly the film surface reflectance 1 (reflectance not including back surface reflection) is as small as 0.3 to 1.3%, and It can be seen from Table 3 that the haze ratio is as small as 0.1 to 0.2 and excellent in transparency, and also excellent in abrasion resistance and stain removal.

After producing the low reflection glasses of Examples 1 to 5,
When the reflectance and the reflection color tone were measured after being left outdoors for a period of one month, there was no change in the measured values before and after being left outdoors, and it was found that each of the examples had excellent durability.

Polycrystalline solar cell (three modules of 57 mm × 28 mm connected in series. Characteristic values Pmax (W) = 0.57, Voc (V) = 1.7,
Isc (mA) = 450 AM1.5, 100 mW / cm ² , 25 ° C.) Used as the front cover glass in Example 4 with the low-reflection glass (low-reflection film on the outside) obtained in Example 4. Using a glass substrate before coating with a low-reflection film, the current value generated in fine weather was measured and compared. The former current value was 397 mA, and the latter current value was 387 mA, and the conversion efficiency of the low-reflection glass was increased by about 3%.

A water-repellent film was coated on the low reflection film obtained in Example 4 as follows. CF ₃ (CF ₂ ) ₇
1 g of (CH ₂ ) ₂ Si (OCH ₃ ) ₃ (heptadecafluorodecyltrimethoxysilane, manufactured by Toshiba Silicone) is dissolved in 98 g of ethanol, and 1.0 g of 0.1 N hydrochloric acid is further dissolved.
The mixture was stirred for 1 hour to obtain a water-repellent agent.

After applying 3 ml of the above-mentioned water-repellent treatment agent to a cotton cloth and applying it to the surface of the low-reflection film of the above-mentioned low-reflection glass plate, the excessively adhered water-repellent treatment agent is wiped off with a new cotton cloth, and the water-repellent agent is removed. A water-treated glass was obtained.

The water-repellent glass was measured for a water droplet weight of 2 using a contact angle meter (CA-DT, manufactured by Kyowa Interface Science).
The static water contact angle was measured as mg. The value of the contact angle is about 125 degrees, which is much larger than the value of the contact angle of about 105 degrees obtained by performing the water-repellent treatment on the untreated glass plate surface in the same manner as described above. It was found to have excellent water repellency. The anti-reflection performance and conversion efficiency of the low-reflection glass subjected to the water-repellent treatment were excellent.

The contact angles of water were measured for all the film surfaces of Examples 1 to 5 using a contact angle meter (CA-DT, manufactured by Kyowa Interface Science) with a water droplet weight of 2 mg. Degrees or less, and showed excellent hydrophilicity.

Next, examples (Examples 6 to 10) relating to application to a glass plate for a solar cell will be described. Example 6 First silica fine particle dispersion (average particle diameter 50
32.0 g of a second silica fine particle dispersion (average particle diameter 300 nm, standard deviation of particle diameter 1.1, major axis length and short length) A mixture of 8.0 g of an average shaft length ratio of 1.02, solid content of 20%, and Nippon Shokubai's "Seahoster KE-W30" at a solid content ratio of 4: 1 was mixed and dispersed in silica fine particles (average). (The particle diameter is 50 nm, which is almost equal to the average particle diameter of the first silica fine particles). To this, 52.6 g of ethanol, 0.5 g of 3 mol / L hydrochloric acid and 6.9 g of tetraethoxysilane were further added and reacted for 12 hours to prepare a coating solution. Non-colored transparent (clear) float glass substrate having a soda-lime silicate glass composition and having a thickness of 4.0 mm (visible light transmittance Ya = 88.5%), total light transmittance = 88.5%, solar radiation transmittance Tg = 79.6
%, UV transmittance Tuviso = 52.0%, visible light reflectance 7.7%, transmission color L of Hunter color system = 94.3, a =
-1.7, b = 0.2, reflection color L = 27.8, a =-
0.5, b = -0.6), the above coating solution is applied by a spin coating method, and further kept in an electric furnace at 500 ° C. for 10 minutes to obtain a low reflection having a haze ratio of 5.1%. A low-reflection glass plate coated with a film (average thickness 250 nm) was obtained.

Example 7 Silica Fine Particle Dispersion (Average Particle Size: 550 nm, Standard Deviation of Particle Size: 1.1, Average of Ratio of Long Axis Length to Short Axis Length: 1.02, Solid Content: 20%, Japan While stirring 40 g of "KE-W50" manufactured by Catalyst, 52.1 g of ethyl cellosolve, 1 g of concentrated hydrochloric acid, and 6.9 g of tetraethoxysilane were sequentially added thereto, and reacted with stirring for 240 minutes to obtain a sol. 3 g of this sol was diluted with 3 g of ethyl cellosolve and 4 g of hexylene glycol,
A coating solution having a solid content of 3% by weight was prepared.

A film was formed on one surface of a float glass substrate having the same composition and thickness as in Example 4 by spin coating using the above coating solution, and further placed in an electric furnace at 700 ° C. for 2 minutes to obtain a haze ratio of 51.7%. A low-reflection glass plate coated with a low-reflection film having an average thickness of 560 nm was obtained. The maximum temperature reached by heating in the electric furnace was 630 ° C.

Example 8 Silica Fine Particle Dispersion (Average Particle Size: 740 nm, Standard Deviation of Particle Size: 1.1, Average Ratio of Long Axis Length to Short Axis Length: 1.02, Solid Content: 20%, Japan While stirring 40 g of "KE-E70" manufactured by Catalyst, 52.1 g of ethyl cellosolve, 1 g of concentrated hydrochloric acid and 6.9 g of tetraethoxysilane were sequentially added thereto, and the mixture was reacted with stirring for 240 minutes. Hexylene glycol 4
g was added and diluted to prepare a coating solution having a solid content of 6%. A film was formed by spin coating on one surface of a float glass substrate having the same composition and thickness as in Example 7, and
Haze rate is 6 by placing in an electric furnace at 700 ° C for 2 minutes.
A low-reflection glass plate coated with a low-reflection film (average thickness 750 nm) having 9.5% was obtained.

Example 9 Silica fine particle dispersion (average particle diameter 300 nm, solid content 20%, "KE"
-W30 "), while stirring, 352.1 g of ethyl cellosolve (52.1 g), concentrated hydrochloric acid (1 g), and tetraethoxysilane (10.4 g) were sequentially added, and the mixture was reacted with stirring for 300 minutes. Hexylene glycol (4 g) was added to and diluted with 3 g of the sol to prepare a coating solution having a solid content of 3%. A film was formed on one surface of a float glass substrate having the same composition and thickness as in Example 7 by spin coating.
A haze ratio of 1 was obtained by placing the furnace in a 00 ° C electric furnace for 2 minutes.
A low-reflection glass plate coated with a low-reflection film (average thickness: 320 nm) having 8.2% was obtained.

Example 10 16 g of the hydrolyzate containing fine particles (average particle diameter 110 nm) used in Example 4 and the hydrolyzate containing fine particles used in Example 7 (average particle diameter of 550 n)
m) 24 g, ethyl cellosolve 20 g, and hexylene glycol 40 g were mixed to prepare a coating solution. The above-mentioned coating solution was applied to the surface of the same glass substrate as used in Example 6 by a gravure coating method, and further kept in an electric furnace at 500 ° C. for 10 minutes, whereby a low reflection film having a haze ratio of 27.2% was obtained. (Average film thickness 570n
A low reflection glass plate coated with m) was obtained.

The reflectance of the low reflection glass of Examples 6 to 10,
The reflection color tone did not change even when measured again after two months, and all the measured values were within the error range of the measuring instrument.

In the above Examples 6 to 10, the form of the silica fine particles (discrimination between non-aggregated fine particles and chain-like aggregated fine particles, and when two types of fine particles are mixed, the notation of “mixing”);
The size of silica fine particles (average particle size), the content of binder in the film (% by weight), the content of silica fine particles (% by weight), the final film thickness (average film thickness), the presence of the silica fine particles in the preparation of the coating solution The presence or absence of hydrolysis of the silicon alkoxide (the presence or absence of “hydrolysis in the presence”), observing the film with an electron microscope from the top of the film, and measuring the film area of 100 square μm (10
μm × 10 μm), the type of substrate glass plate (color and thickness (mm)), and film surface reflectivities 1 and 2 of the obtained low reflection glass plate.
Reflection color a / b, dirt removal, initial haze ratio (%), initial total light transmittance (%), and fastness test (500 g)
Table 3 shows the evaluation results of the haze ratio (%) and the total light transmittance (%) after 1000 reciprocations under a load of / cm ² . The value of the reflected light saturation calculated from the reflected color tone [(a ² + b ² ) ^1/2 ]
Was 4 or less in all Examples. From the description in Table 3, in Examples 6 to 8 and 10, the obtained low reflection glass plate has a higher total light transmittance than the total light transmittance of the glass substrate. It can be seen that the obtained low reflection glass plate has a total light transmittance substantially equal to the total light transmittance of the glass plate substrate. Example 6
The low-reflection glass having a high haze ratio of 10 to 10 is not very suitable as a window glass for automobiles and buildings, but can be suitably used as a glass plate for a solar cell substrate and a glass plate for a solar water heater.

[0074]

[Table 3] ─────────────────────────────────── Example 6 Example 7 Example 8 Example 9 Example 10 ─────────────────────────────────── Silica fine particles Non-agglomerated / mixed Non-agglomerated Same as left Same as left Non Aggregation / mixing Average particle size 50 nm 550 nm 740 nm 300 nm 160 nmBinder amount 20% 20% 20% 30% 22% Silica fine particle amount 80% 80% 80% 70% 78% Average film thickness 250 nm 560 nm 750 nm 320 nm 570 nm Yes Yes Yes Fine particle density 650 100 30 300 6500 (10 μm square) Substrate (color, thickness mm) Clear 4.0 Clear 2.8 Clear 2.8 Clear 2.8 Clear 4.0 ----------------------------- −−−−−−−−−−−−−−−−−−−−−− Film reflectance 1 0.5% 0.2% 0.2% 0.3% 0.2% Film reflectance 2 4.3% 2.6% 2.9% 3.9% 3.4 % Reflective color a / b -1.9 / 0 1.0 / -1.3 -0.3 / 0.8 -0.8 / -0.8 -0.1 / 0.9 Stain removal ○ ○ ○ ○ ○ Initial haze rate (%) 5.1 51.7 69.5 18.2 27.1 Initial total light transmittance 91.5 91.2 90.5 89.5 91.4 After fastness test Haze rate (%) 5.3 52.6 70.8 19.0 28.5 Total light transmittance (%) 91.4 91.3 90.7 89.5 91.2 ───────────────────────────────────

In Examples 6 to 10, the changes in the film surface reflectances 1, 2 and the reflection color tone before and after the robustness test were within the measurement error range of the spectrophotometer, and it could be determined that there was no optical thickness change. Was. After the fastness test, the haze increased slightly, but the total light transmittance hardly changed.Therefore, there was no decrease in diffuse transmitted light caused by light scattering by the fine particles. It can be seen that they are in close contact.

[Comparative Example 1] 45 g of ethanol, 8.67 g of tetraethoxysilane, and 1 g of concentrated hydrochloric acid were added to 12.5 g of a silica fine particle dispersion (average particle size: 50 nm, solid content: 20%, the above-mentioned "Snowtex OL" manufactured by Nissan Chemical Industries, Ltd.). Are sequentially added,
The mixture was stirred for 24 hours to cause a hydrolysis reaction. The mixture was further diluted with ethyl cellosolve to prepare a coating liquid (containing silica fine particles and ethyl silicate at a weight ratio of 4: 1 in terms of silica, respectively).

Comparative Example 2 Tetramethoxysilane
26.8 g of ethanol 36.8 g, 3 mol / L hydrochloric acid 7.2
g were mixed and reacted for 12 hours to hydrolyze tetramethoxysilane. A coating liquid was prepared by mixing 160 g of a chain-like aggregated silica fine particle dispersion (average primary particle size: 25 nm, solid content: 15%, “Snowtex-OUP” manufactured by Nissan Chemical Co., Ltd.) and the above hydrolyzed liquid.

[Comparative Example 3] 21 g of tetraethoxysilane
While stirring, 29 g of ethyl cellosolve and 10 g of 1 mol / L hydrochloric acid were added and reacted for 12 hours. This reaction solution
3.3 g of a silica fine particle dispersion (average particle size 50 nm, solid content 20%, "Snowtex O" manufactured by Nissan Chemical Co., Ltd.
L ")) at a rate of 3.3 g and diluted with ethyl cellosolve to prepare a coating solution.

[Comparative Example 4] 74.53 g of ethanol, 3.47 g of tetraethoxysilane and 2 g of concentrated hydrochloric acid were added to 20 g of a silica fine particle dispersion (average particle size: 30 nm, solid content: 20%, “Snowtex O” manufactured by Nissan Chemical Industries, Ltd.). Add sequentially, 18
The mixture was stirred for a time to cause a hydrolysis reaction. The mixture was further diluted with ethyl cellosolve to prepare a coating liquid (containing silica fine particles and ethyl silicate at a weight ratio of 4: 1 in terms of silica, respectively).

Comparative Example 5 20 g of silica fine particle dispersion (average particle size: 30 nm, solid content: 20%, “Snowtex O” manufactured by Nissan Chemical Industries, Ltd.) was added to 70 g of ethanol, and a hydrolytic condensation polymerization solution of ethyl silicate (trade name: HAS-10, manufactured by Colcoat Co., Ltd., SiO ₂ content 10% by weight) 10 g
Were sequentially added to form a coating liquid (containing silica fine particles and ethyl silicate at a weight ratio of 4: 1 in terms of silica, respectively).

Comparative Example 6 Tetramethoxysilane 8.4
g, 53.8 g of ethanol, 4.5 g of 3 mol / L hydrochloric acid
Were mixed to obtain a hydrolysis solution reacted for 24 hours. Further, a silica fine particle dispersion (average particle size 50 nm, solid content 2
0%, "Snowtex-OL" manufactured by Nissan Chemical Co., Ltd.)
33.3 g was added, and ethyl cellosolve was further added to dilute it to obtain a coating solution.

Comparative Example 7 Tetramethoxysilane was added to 33.3 g of a silica fine particle dispersion (average particle size: 30 nm, solid content: 20%, “Snowtex-O” manufactured by Nissan Chemical Industries, Ltd.).
4 g, ethanol 57.3 g, 3 mol / L hydrochloric acid 1.0
g were mixed and reacted for 12 hours to hydrolyze tetramethoxysilane to prepare a coating solution. Using this, the same glass substrate (green coloration,
(Thickness: 3.4 mm), applied, dried and heat-treated in the same manner as in Example 1 to obtain glass plates having a silica uneven film having a thickness of 125 nm formed on each surface.

Using the coating liquids prepared in Comparative Examples 1 to 7, the heat treatment for 10 minutes in an electric furnace at 600 ° C. was performed in place of the heat treatment for 2 minutes in an electric furnace at 700 ° C. in Example 1. Using the same glass substrate (green coloring, 3.4 mm thickness) as used in Example 1 except that the coating was performed and heat-treated in the same manner as in Example 1, silica having the thickness shown in Tables 4 and 5 was used. A glass coated with a membrane was obtained. Tables 4 and 5 show the evaluation results of the obtained glass plates. In the column of "fine particle density" in the table, "not determined" means that the fine particles are buried in the binder and the number of fine particles cannot be counted.

From the description in Table 4, the following can be understood for each comparative example. In Comparative Example 1 in which the binder amount exceeds 40%, the film surface reflectance is high. In Comparative Examples 2 and 5 in which the average particle diameter of the non-agglomerated silica fine particles is less than 40 nm and "hydrolysis in the presence of the silica fine particles" is not performed, the abrasion resistance and stain removal properties are inferior. In Comparative Example 3 in which “hydrolysis in the presence of silica fine particles” was not performed, the film surface reflectance was high and the abrasion resistance was poor. In Comparative Example 4 in which the average particle size of the non-agglomerated silica fine particles is less than 40 nm, the film surface reflectance, particularly the film surface reflectance 1 not including the back surface reflection, is high and the stain removal property is poor. Comparative Example 6 in which the amount of binder exceeds 40% and "hydrolysis in the presence of silica fine particles" is not performed
Is inferior in wear resistance. In Comparative Example 7 in which the average particle diameter of the non-agglomerated silica fine particles is less than 40 nm and the amount of the binder exceeds 40%, the film surface reflectance is high.

[0085]

Table 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4微粒子 Silica fine particles Non-aggregated Chain-like aggregate Non-aggregated Same as on the left Average particle size 50 nm 25 nm 50 nm 30 nm % 20% 33% 20% Silica Fine particle amount 50% 80% 67% 80% Average film thickness 125 110nm 120nm 110nm Hydrolysis Yes No No Yes Fine particle density 850 2800 650 2500 (1μm square) Substrate (color , Thickness mm) Clean 3.4 Clean 3.4 Clean 3.4 Clean 3.4 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Surface reflectance 1 (%) 2.4 0.5 1.9 1.9 Film surface reflectivity 2 (%) 5.8 3.8 5.3 5.3 Haze ゛ ratio (%) 0.1 5.1 0.4 0.1 a / b -1.2 / -1.0 -1.5 / -0.5 -1.4 / -0.1 -1.1 / -1.0 taper wear 1 ○ (1.5) × × ○ (1.2) taper wear 2 ○ (1.6) × × (1.4) stain removal properties ○ × ○ △ ────────────────────────────────

[0086]

Table 5 Comparative Example 5 Comparative Example 6 Comparative Example 7微粒子 Silica fine particles Non-aggregated Same as on the left Same as on the left Average particle size 30 nm 50 nm 30 nm binder amount 20% 67% 67% silica particle amount 80% 33% 33% average film Thickness 110nm 130nm 120nm Hydrolysis No No Yes Fine particle density 2300 800 Indeterminable Substrate (color, thickness mm) Clean 3.4 Clean 3.4 Clean 3.4 --- --- --- --- --- --- --- --- --- −−−−−−−− Reflectance of film surface 1 (%) 1.9 1.6 3.3 Reflectance of film surface 2 (%) 5.4 4.9 6.7 Haze ゛ ratio (%) 0.1 0.2 0.1 a / b -1.2 / 0.1 -1.4 / -0.6 -1.1 / -1.0 Abrasion 1 × × ○ (1.2) Abrasion 2 × × ○ (1.4) Stain removal × ○ ○ ───────────────────── ───────

Comparative Example 8 One side surface of a float glass substrate having the same composition and thickness as used in Example 4 was # 1
A ground glass whose surface was roughened by rubbing with # 00 abrasive sand was prepared. The haze ratio and the total light transmittance of this ground glass were measured by a haze meter. Haze rate is 82.6%
And the total light transmittance was 75.4%. The mechanical strength of the ground glass was reduced to about 40% of the strength of the original glass.

Comparative Example 9 A ground glass was prepared in the same manner as in Comparative Example 6, except that # 1000 abrasive sand was used in place of # 100 abrasive sand in Comparative Example 6, and the haze ratio and the total light transmittance were obtained. Was measured. The haze ratio was 81.4% and the total light transmittance was 83.0%. The mechanical strength of the ground glass was reduced to about 50% of the strength of the original glass.

[0089]

According to the present invention, a coating solution obtained by hydrolyzing a metal compound hydrolyzable in the presence of silica fine particles is used, and relatively large silica fine particles are used. By using the fine particles and the binder in a specific ratio, a remarkably low reflectance and a high film strength can be obtained, the dirt removal property is improved, and the reflectance does not change with time.

Further, according to the present invention, even when the glass substrate is heated to a temperature higher than the softening point, no warpage of the glass due to shrinkage of the film occurs. This is mainly because the silica fine particles having almost no shrinkage constitute the film, so that the bonding between the film and the glass is reduced and the contact between the particles is also reduced. In particular, in the film obtained by co-hydrolysis, the binder concentration is high on the surface of the silica fine particles, and the binder does not form a film on the surface of the glass substrate, so that it is considered that the shrinkage of the binder does not easily act on the glass. Therefore, for example, even in the case of forming into a curved surface shape such as glass for automobiles, the same processing as glass having no film can be performed, and the manufacturing cost can be reduced. In addition, even in applications such as solar cell substrates and architectural windows, glass flatness can be maintained even when high heat treatment is performed to improve film strength, which is preferable.

Further, according to the present invention, since the outermost surface of the low-reflection glass is made uneven, the hydrophilicity of silicon dioxide is improved, and the glass surface is less likely to be fogged by attached water vapor. Even if water drops adhere, the contact angle is small,
As it has a very hydrophilic surface, dirt such as dust can be easily washed away. Since water droplets do not easily remain, it has an antifouling property in which dirt such as water marks does not easily occur on the surface.

Further, the single-layer low-reflection film according to the present invention comprises:
Compared with multilayer films, not only the manufacturing cost is reduced, but also in the reflection performance, the reflectance is low in a wide wavelength range,
There is an advantage that the rise of the reflectance with respect to the incident angle is small and the saturation of the reflected light is small. Such performance is particularly useful for windows for automobiles and glass sheets for solar cells. In addition, since the decrease in reflection increases the transmittance, it is suitable for a solar cell glass that converts light into other energy, and has a total light transmittance equal to or higher than the total light transmittance of the glass substrate used. Low-reflective glass articles having a total light transmittance of at least 88%.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing the structure of a low reflection film according to one embodiment of the present invention.

FIG. 2 is an electron micrograph showing the structure of a low reflection film of a comparative example.

FIG. 3 is an electron micrograph showing the structure of a low reflection film according to another embodiment of the present invention.

FIG. 4 is an electron micrograph showing the structure of a low reflection film according to another embodiment of the present invention.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Tetsuro Kawahara 3-5-11 Doshomachi, Chuo-ku, Osaka Japan F-term in Sheet Glass Co., Ltd. (Reference) 4G059 AA01 AC04 EA05 EB07 EB09 FA05

Claims (29)

[Claims] 1. A low-reflection glass article having a low-reflection film comprising silica fine particles and a binder formed on a glass substrate, wherein the low-reflection film has a weight ratio of the silica fine particles and the binder of 60:40 to 95: 5. And the low-reflection film has (1) an average particle size of 40
Raw material fine particles comprising at least one of non-aggregated silica fine particles having a mean primary particle diameter of 10 to 100 nm, (2) a hydrolyzable metal compound, (3) water, and (4) a solvent. And coating the coating solution prepared by hydrolyzing the hydrolyzable metal compound in the presence of the raw material fine particles on the glass substrate, followed by heat treatment. A low reflection glass article characterized by the following. 2. The hydrolyzable metal compound is at least one metal alkoxide selected from the group consisting of silicon alkoxide, aluminum alkoxide, titanium alkoxide, zirconium alkoxide and tantalum alkoxide, and the binder is a metal of the metal compound. The low reflection glass article according to claim 1, which is an oxide of: 3. The low reflection glass article according to claim 1, wherein the low reflection film contains silica fine particles and a binder in a weight ratio of 65:35 to 85:15, respectively. 4. The low reflection light according to claim 1, wherein the non-agglomerated silica fine particles in the coating liquid have a ratio of the major axis length to the minor axis length of 1.0 to 1.2. Glass articles. 5. The low reflection glass article according to claim 1, wherein the non-agglomerated silica fine particles in the coating liquid have a primary particle size standard deviation of 1.0 to 1.5. 6. The low-reflection glass article according to claim 1, wherein the raw material fine particles consist only of the non-agglomerated silica fine particles having an average particle size of 40 to 500 nm. 7. The raw material fine particles have a thickness of 100 to 1000 nm.
The low-reflection glass article according to any one of claims 1 to 5, comprising only the non-agglomerated silica fine particles having an average particle size of: 8. The raw material fine particles are composed of only the non-agglomerated silica fine particles, and the non-agglomerated silica fine particles are
(1) 70 to 95% by weight of first non-agglomerated silica fine particles having an average particle diameter of 40 to 200 nm, and (2) 200 nm
The second non-agglomerated silica fine particles having a mean particle size of not more than 3000 nm and not more than 3000 nm and at least 100 nm larger than the average particle size of the first non-agglomerated silica fine particles, comprising 5 to 30% by weight. 2. The low reflection glass article according to claim 1. 9. The low reflection film is 1 μm × 1 μm when viewed from above the film.
In a 1 μm square, fine particles have 30 to
3000 particles are present side by side.
The low-reflection glass article according to claim 6, having an average particle size of ~ 500 nm. 10. The low reflection film has a thickness of 10 μm when viewed from above the film.
Fine particles are 10 to 50,000 in a square of m × 10 μm.
The low-reflection glass article according to claim 7, wherein the fine particles have an average particle diameter of 100 to 1000 nm, which are present side by side on the surface of the film. 11. The low reflection film has a thickness of 10 μm when viewed from above the film.
Fine particles having an average particle diameter Dnm of 40 to 1000 nm are placed on the surface of the film in a square of mx10 μm.
The low reflection glass article according to claim 6, wherein 0 / D ^{2 to} 10,000,000 / D ² are present side by side. 12. The low reflection film according to claim 1, wherein one fine particle is present or two to five fine particles are stacked in the thickness direction when viewed from a cross section in the thickness direction of the film.
The low-reflection glass article according to any one of claims 1 to 7. 13. The low-reflection glass article according to claim 8, wherein the low-reflection film has a surface occupied area of 50% or less of fine particles derived from the second non-agglomerated silica fine particles when viewed from above the film. 14. The binder has a thickness of 1 to 100 nm and a thickness of 2 to 9% of an average particle size of the silica fine particles,
The entire surface of the silica fine particles is coated.
14. The low reflection glass article according to any one of 13). 15. The low reflection film has a thickness of 90 nm or more and 350 n or more.
15. Any one of claims 1 to 14 having an average thickness of not more than m.
Item 6. The low reflection glass article according to item 1. 16. The low reflection film has a thickness of 90 nm or more and 180 n or more.
15. Any one of claims 1 to 14 having an average thickness of not more than m.
Item 6. The low reflection glass article according to item 1. 17. The low-reflection glass article according to claim 1, wherein the heat treatment is performed so that the maximum temperature of the glass substrate coated with the coating liquid is 200 ° C. or higher. 18. The low reflection glass according to claim 1, wherein the low reflection film has a surface average roughness (Ra) of 3 to 50 nm as measured by an AFM (atomic force microscope). Goods. 19. The glass substrate has a plate shape, and the low-reflection film has a standard light A defined by JIS-Z8720.
To the plate-like glass substrate at an incident angle of 12 degrees from the low-reflection film surface side, and a film surface reflectance of 2% or less expressed as a film surface reflectance not including the reflected light on the back surface of the plate-like glass substrate. Claims 1 to 6, 9, 11, 12, and 14 to having surface reflectance.
19. The low-reflection glass article according to any one of 18. 20. The glass substrate according to claim 1, wherein the low-reflection glass article has a haze ratio of 30% or less.
20. The low-reflection glass article according to any one of items 19 to 19. 21. The glass substrate according to claim 1, wherein the glass substrate has a haze ratio of 1% or less.
The low reflection glass article according to any one of 6, 9, 11, 12, and 14 to 19. 22. The glass substrate, wherein the glass substrate is plate-like and the low-reflection glass article has a total light transmittance equal to or higher than the total light transmittance of the glass substrate;
The low-reflection glass article according to any one of claims 1 to 5, which has a haze ratio of 90%. 23. The low-reflection glass article according to any one of claims 1 to 6, 9, 11, 12, 12, 14 to 19, and 21, wherein the low-reflection glass article is a vehicle window. 24. The low-reflection glass article is an architectural window, a show window, a display glass plate, or an optical glass part.
22. The low reflection glass article according to any one of 19 and 21. 25. The low reflection glass article is a glass plate for a solar cell or a glass plate for a solar water heater.
21. The low-reflection glass article according to any one of Items to 5, 7, 8, 10 to 18, and 20. 26. A low-reflection glass article having a low-reflection film comprising silica fine particles and a binder formed on a float glass plate having a total light transmittance of 85% or more and a soda lime silicate glass composition. The silica fine particles and the binder are in a weight ratio of 65: 35-9.
5: 5 respectively, and the binder is coated on the surface of the silica fine particles in a film thickness of 1 to 100 nm, and is equal to or less than the total light transmittance of the glass substrate. A low-reflection glass article for a solar cell or a solar water heater, having a high total light transmittance. (1) Non-agglomerated silica fine particles having an average particle size of 40 to 1000 nm and an average primary particle size of 10 to 100
(2) a hydrolyzable metal compound, (3) water, and (4) a solvent, the raw material particles and the metal compound, and the metal compound is a metal. In terms of oxide, the weight ratio is 60:
Covering the glass substrate with a coating solution prepared by mixing and hydrolyzing the metal compound in the presence of the raw material fine particles so as to contain them in a ratio of 40 to 95: 5, respectively, and heating the glass substrate. A method of producing a coated glass article characterized by: 28. The coated glass article according to claim 27, wherein the hydrolyzable metal compound contains at least one metal alkoxide selected from the group consisting of silicon alkoxide, aluminum alkoxide, titanium alkoxide, zirconium alkoxide and tantalum alkoxide. How to make. 29. The coating liquid includes 100 parts by weight of the metal compound (in terms of metal oxide), 150 to 1900 parts by weight of the raw material particles, 0 to 200 parts by weight of the catalyst, 50 to 10000 parts by weight of water, and the solvent. 100
The method for producing a coated glass article according to claim 27 or 28, having a raw material mixing ratio of 0 to 500,000 parts by weight.