WO2023026670A1

WO2023026670A1 - Antireflective glass

Info

Publication number: WO2023026670A1
Application number: PCT/JP2022/025359
Authority: WO
Inventors: 翔一横山; 翔一石川
Original assignee: フクビ化学工業株式会社
Priority date: 2021-08-23
Filing date: 2022-06-24
Publication date: 2023-03-02
Also published as: CN117425632A; JPWO2023026670A1; TW202313511A

Abstract

Provided is an antireflective glass comprising a glass substrate, an antireflective film and a protective layer in this order, in which the antireflective film is composed of a medium-to-small refractive index layer having a refractive index of 1.36 to 1.45 and a thickness of 150 to 210 nm, a medium refractive index layer having a refractive index of 1.56 to 1.79 and a thickness of 90 to 140 nm, a large refractive index layer having a refractive index of 1.75 to 1.87 and a thickness of 30 to 50 nm, and a small refractive index layer having a refractive index of 1.27 to 1.35 and a thickness of 70 to 75 nm in this order when observed from the glass substrate side, the refractive index of the large refractive index layer is larger than that of the medium refractive index layer, the protective layer has a refractive index of 1.43 to 1.48 and a thickness of 20 to 30 nm, each of the large refractive index layer, the small refractive index layer and the protective layer contains (A) an aluminum salt hydrate, the luminous average reflectance of each surface is 0.6% or less at a wavelength of 380 to 780 nm, and the luminous average transmittance of each surface is 98% or more at a wavelength of 380 to 780 nm. The antireflective glass has high antireflective performance and excellent alkali resistance, and can be used suitably for the production of an antireflective hardened glass.

Description

anti-reflection glass

The present invention relates to antireflection glass imparted with a high degree of antireflection performance, which is suitably used for manufacturing antireflection tempered glass.

Tempered glass with enhanced glass strength is widely used for applications such as window glass in automobiles and houses, but recently it has been used in various applications such as full-face protective panels for capacitive touch panels, digital cameras, and mobile phones. It is also used for applications such as mobile device displays.
Tempered glass for the latter use has a small and complicated shape, and requires shape processing such as cutting, edge processing, and drilling. However, since it is difficult to process these shapes after tempering, tempering treatment has been performed after preliminarily processing the glass substrate into the final product shape.

As methods for strengthening glass, physical strengthening by rapid cooling and chemical strengthening by ion exchange are known. The physical strengthening method is intended for glass having a thickness of several mm or more, and is not effective for thin glass substrates. Therefore, the chemical strengthening method is generally adopted for thin glasses such as the protective panels and displays.

Chemical strengthening by ion exchange is performed by replacing metal ions with a small ionic radius (eg sodium ions) contained in the glass with metal ions with a larger ionic radius (eg potassium ions). That is, by substituting metal ions having a smaller ionic radius with metal ions having a larger ionic radius, a compressive stress layer is formed on the glass surface.
As a result, in order to break this glass, in addition to the force to break the bonds between molecules, the force to remove the compressive stress on the surface is required, and the strength is significantly improved compared to ordinary glass. .

By the way, even tempered glass strengthened by chemical treatment by ion exchange may be required to have an antireflection function and other functions. requested.
In order to impart an antireflection function, an antireflection film with a low refractive index may be formed on the glass surface. Methods for forming such an antireflection film are roughly classified into a vapor deposition method and a sol-gel method.
Because the vapor deposition method requires extremely expensive equipment, it is not widely used industrially. Currently, a coating liquid containing fine particles is applied and heat-treated to form an anti-reflection film that gels. The sol-gel method is predominant due to its low production cost and high yield.
As an antireflection film formed by such a sol-gel method, for example, one containing a hydrolytic condensate of a silicon compound, a metal chelate compound, and silica particles with a low refractive index is known (see Patent Document 1). .

Forming an antireflection film on the surface of tempered glass obtained by chemical treatment had a major problem that had to be solved.
In the past, after forming an antireflection film, potassium ions could not permeate the inside of the glass, making it impossible to strengthen the glass. . In this case, the advantage of the sol-gel method, which is capable of processing a large area, is completely lost, resulting in a marked drop in productivity.

In order to solve the above problems, a method of chemically strengthening the glass after forming an antireflection film has been proposed.
One is a method of strengthening glass by ion exchange using the interstitial spaces (hereinafter referred to as voids) between the particles of the inorganic fine particles contained in the antireflection film formed on the surface (Patent Reference 2). However, this method has the problem that it is difficult to control the voids that allow ion exchange.
To solve the above problem, a method has been proposed in which hollow particles having a space inside are used and ion exchange is performed through the internal space instead of using the gaps between particles (Patent Document 3). Since this method uses particles having a predetermined spatial volume in advance, it was easier to set conditions for ion exchange than the above-described void method. On the other hand, however, there are not many hollow inorganic particles and industrial production methods are limited, so the types of inorganic particles that can be used are limited.

By the way, in order to improve the antireflection performance of the antireflection film, a multi-layer antireflection film has been developed in which a high refractive index layer and a medium refractive index layer are provided in addition to the low refractive index layer.
Zirconium oxide particles and titanium oxide particles having a higher refractive index than silica particles must be blended in these high refractive index layers and medium refractive index layers in order to develop a predetermined refractive index. However, since it is difficult to obtain hollow particles of these high refractive index particles, ion exchange using the internal space of the particles cannot be performed. It was difficult to strengthen the glass by ion exchange through multiple refractive index layers after the formation of the protective film.
The inventors of the present application have previously studied and proposed a method for producing antireflection tempered glass having such a multi-layered antireflection film (Patent Document 4).

Japanese Patent Application Laid-Open No. 2002-221602 JP-A-2002-234754 JP 2011-88765 A JP 2017-178634 A

The inventors of the present application faced the following problems in the process of developing antireflection tempered glass.
The purpose of tempered glass is to remove organic and inorganic substances adhering to the surface of the glass in order to improve the adhesion between the tempered glass and the anti-reflection film. An alkaline cleaning step is required to prevent loss (burning prevention). Furthermore, alkali cleaning is performed for various purposes such as removing impurities adhered during tempering of the glass.
Specifically, discoloration includes blue discoloration, which is a phenomenon of lack of alkali ions on the glass surface due to moisture erosion in the air, and a phenomenon in which carbonic acid compounds are generated by dry concentration of moisture containing alkali ions on the glass surface and carbon dioxide gas. There is white discoloration. Once these scorching occurs, it is a phenomenon that is difficult to repair unless the surface is physically polished.
However, by carrying out the alkali cleaning, the antireflection film formed on the glass surface is damaged, becomes mottled and becomes uneven, or the film thickness is reduced, and the desired antireflection performance is not exhibited, or There was a problem that the color changed and the product value was lost.

The inventors of the present application have investigated the cause of deterioration of the antireflection film due to washing with alkali, and found that the presence of aluminum salt hydrate in the antireflection film develops alkali resistance and prevents deterioration of the antireflection film. The discovery led to the completion of the present invention.
That is, according to the present invention, an antireflection glass comprising a glass substrate, an antireflection film and a protective layer in this order,
The antireflection film, from the glass substrate side,
a medium-to-low refractive index layer having a refractive index of 1.36 to 1.45 and a layer thickness of 150 to 210 nm;
a medium refractive index layer having a refractive index of 1.56 to 1.79 and a layer thickness of 90 to 140 nm;
a high refractive index layer having a refractive index of 1.75 to 1.87 and a layer thickness of 30 to 50 nm;
A low refractive index layer having a refractive index of 1.27 to 1.35 and a layer thickness of 70 to 75 nm.
The protective layer has a refractive index of 1.43 to 1.48 and a layer thickness of 20 to 30 nm,
The high refractive index layer, the low refractive index layer and the protective layer contain (A) an aluminum salt hydrate,
The above antireflection glass is characterized by having an average luminous reflectance of 0.6% or less on both surfaces at a wavelength of 380 to 780 nm and an average luminous transmittance of 98% or more at a wavelength of 380 to 780 nm.

In the antireflection glass invention,
1) the medium-low refractive index layer and the medium-low refractive index layer further contain (A) an aluminum salt hydrate;
2) With respect to 100 parts by mass of a binder component in which the protective layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R _n —Si(OR ¹ ) _4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, ^R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 3 to 25 parts by mass of an aluminum salt hydrate and (C) a cured product of a protective layer composition containing 1 to 20 parts by mass of a metal chelate compound;
3) With respect to 100 parts by mass of a binder component in which the low refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R _n —Si(OR ¹ ) _4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, ^R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 3 to 25 parts by mass of aluminum salt hydrate, (C) 1 to 20 parts by mass of metal chelate compound, and (D) 25 to 90 parts by mass of silica particles. consisting of
4) With respect to 100 parts by mass of a binder component in which the high refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R _n —Si(OR ¹ ) _4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, ^R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 1 to 15 parts by mass of aluminum salt hydrate, and (E) 40 to 130 parts by mass of metal oxide particles.
5) With respect to 100 parts by mass of a binder component in which the medium refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R _n —Si(OR ¹ ) _4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, ^R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 1 to 15 parts by mass of aluminum salt hydrate, and (E) 40 to 130 parts by mass of metal oxide particles.
6) With respect to 100 parts by mass of a binder component in which the medium-to-low refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R _n —Si(OR ¹ ) _4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, ^R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 3 to 25 parts by mass of aluminum salt hydrate, (C) 1 to 20 parts by mass of a metal chelate compound, and (D) 25 to 90 parts by mass of silica particles. consisting of a cured product;
7) the glass substrate is alkali aluminosilicate glass;
8) It is preferable that the antireflection glass is alkali-resistant antireflection glass for chemical strengthening.
The mass part of the silica particles in each layer is either one of the solid silica particles and the hollow silica particles, or the total value. Further, the parts by mass of the metal oxide particles in each layer may be the value of parts by mass of one type of metal oxide particles, or the total value of parts by mass of two or more different types of metal oxide particles. good.

Furthermore, antireflection strengthening characterized by including a step of chemically strengthening the antireflection glass in an ion-exchange metal salt melt, and a step of alkali washing before or after the chemical treatment step. An invention is provided that features a method of making glass.

The antireflection glass provided by the present invention is preferably used for manufacturing antireflection tempered glass with high antireflection performance. Specifically, after forming an antireflection film on the surface of a glass substrate, it is possible to strengthen the glass by washing with alkali and batch tempering treatment, and it is useful for industrial production of high-quality antireflection tempered glass that is smooth and has excellent transparency.
Glass strengthening by chemical treatment makes it possible to strengthen by a batch treatment using internal cavities such as hollow silica particles or interstitial spaces between oxide particles. Furthermore, since the antireflection glass has excellent alkali resistance, the antireflection performance deteriorates due to nonuniformity of the antireflection film and reduction in the film thickness even after the alkali cleaning process necessary for smoothing the glass surface and preventing burning. can be prevented.
As a result, a high-quality anti-reflection tempered glass product having high anti-reflection performance, excellent smoothness and no deterioration in transparency can be produced with extremely high productivity and at low cost. The obtained antireflection tempered glass has a multi-layered antireflection film, and therefore has a low reflectance and excellent antireflection performance against light of a wide range of wavelengths.
Such antireflection tempered glass products are suitably used for products with thin glass substrates, such as front protective panels for capacitive touch panels, and displays for various mobile devices such as digital cameras and mobile phones.

<Anti-reflection glass>
The antireflection glass of the present invention basically comprises a glass substrate, an antireflection film and a protective layer, which are laminated in this order.
The antireflection film, from the glass substrate side,
a medium-to-low refractive index layer having a refractive index of 1.36 to 1.45 and a layer thickness of 150 to 210 nm;
a medium refractive index layer having a refractive index of 1.56 to 1.79 and a layer thickness of 90 to 140 nm;
a high refractive index layer having a refractive index of 1.75 to 1.87 and a layer thickness of 30 to 50 nm;
A low refractive index layer having a refractive index of 1.27 to 1.35 and a layer thickness of 70 to 75 nm is formed in this order, and the refractive index of the high refractive index layer is set higher than that of the medium refractive index layer. be.
The protective layer has a refractive index of 1.43-1.48 and a layer thickness of 20-30 nm.
The antireflection glass is characterized by an average luminous reflectance of 0.6% or less on both surfaces at a wavelength of 380 to 780 nm and an average luminous transmittance of 98% or more at a wavelength of 380 to 780 nm.
The greatest feature of the present invention is that the high refractive index layer, the low refractive index layer and the protective layer contain (A) an aluminum salt hydrate. By including (A) aluminum salt hydrate in these layers, the antireflection glass exhibits alkali resistance, and deterioration and damage of the antireflection film can be prevented. In order to impart alkali resistance, (A) aluminum salt hydrate should be present in at least the high refractive index layer, the low refractive index layer and the protective layer, and further the medium refractive index layer and the medium low refractive index layer. If it is also present, it is preferable because the alkali resistance is remarkably improved.

<Glass substrate>
The glass substrate is not particularly limited as long as it has a composition that can be strengthened by chemical treatment, but glass containing alkali metal ions or alkaline earth metal ions with a smaller ionic radius is suitable.
Specifically, soda-lime silicate glass, alkali aluminosilicate glass, alkali borosilicate glass, etc., may be mentioned. Among these, those containing sodium ions are preferable, and contain 5% by weight or more of sodium ions. Glass is most preferred.
Alkali aluminosilicate glasses are preferably used because of their high substitution of potassium ions, resulting in deeper reinforcing layers, and their high transparency.
The thickness of the glass substrate is usually 2 mm to 0.2 mm. If it exceeds 2 mm, the strength of the tempered glass may be insufficient, and it is not suitable for chemical strengthening by the ion exchange method. The area of the substrate is not particularly limited, and is arbitrarily determined according to the size of the final product and the limitations of the manufacturing process.

<Anti-reflection film>
An anti-reflection film is usually laminated on the glass substrate. Alternatively, an antistatic layer, a silica particle layer, a primer layer, or a smoke layer may be provided between any of the following adjacent refractive index layers.
The antireflection film in the present invention is a multilayer antireflection film composed of four refractive index layers having the following properties.
Medium-low refractive index layer: refractive index of 1.36 to 1.45, layer thickness of 150 to 210
nm
Medium refractive index layer: a refractive index of 1.56 to 1.79 and a layer thickness of 90 to 140 nm
High refractive index layer: a refractive index of 1.75 to 1.87 and a layer thickness of 30 to 50 nm
Low refractive index layer: a refractive index of 1.27 to 1.35 and a layer thickness of 70 to 75 nm
The refractive index of the high refractive index layer is set higher than that of the medium refractive index layer.
The four refractive index layers are arranged in the order from the glass substrate side: medium-low refractive index layer, medium refractive index layer, high refractive index layer, and low refractive index layer.
By using the four-layer antireflection film, the average luminous reflectance on both sides of the antireflection glass and antireflection tempered glass at a wavelength of 380 to 780 nm is 0.6% or less, and the average luminous transmission at a wavelength of 380 to 780 nm. When the ratio becomes 98% or more, a high-performance antireflection product can be obtained.
The values of the average luminous reflectance and the average luminous transmittance are values before the glass is tempered, but they are maintained and expressed after the glass is tempered.

<Medium-low refractive index layer>
This is the refractive index layer positioned at the bottom layer (on the side of the glass substrate) of the antireflection film. It is usually laminated on a glass substrate.
The medium-to-low refractive index layer has a refractive index of 1.36 to 1.45 and a layer thickness of 150 to 210 nm. Preferably, the refractive index is between 1.38 and 1.43 and the layer thickness is between 170 and 205 nm.

Since the medium-to-low refractive index layer needs to be strengthened by chemical treatment after the formation of the antireflection film and the protective layer, a solution of the medium-to-low refractive index layer composition containing the following components is prepared, and the solution is coated. , drying, and heating.
(B) With respect to 100 parts by mass of a binder component composed of an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof (hereinafter referred to as "alkoxysilane compound, etc."),
R _n —Si(OR ¹ ) _4-n (1)
(wherein R is an alkyl group, an alkenyl group or an alkoxyalkyl group,
R ¹ is an alkyl group, an alkoxyalkyl group, an acyloxy group or a halogen atom, and n is an integer of 1 or 2)
(A) 3 to 25 parts by mass of aluminum salt hydrate,
(C) 1 to 20 parts by mass of a metal chelate compound, and (D) 25 to 90 parts by mass of silica particles. (A) the aluminum salt hydrate may be excluded from the composition.

[Alkoxysilane compound or its hydrolyzate]
It is a component that serves as a binder for forming a dense, high-strength film that has good adhesion to a glass substrate, and is represented by the above formula (1).
In the formula, R is an alkyl group, alkenyl group or alkoxyalkyl group.
The number of carbon atoms in the alkyl group is preferably 1-9, more preferably 1-5. Examples of alkyl groups include methyl, ethyl, trimethyl, propyl, butyl, tetramethyl, pentyl, and hexyl groups.
The number of carbon atoms in the alkenyl group is preferably 1-9, more preferably 1-5. Alkenyl groups include ethenyl, propenyl, butenyl, pennyl, and hexenyl groups.
The number of carbon atoms in the alkoxyalkyl group is preferably 1-9, more preferably 1-5. The alkoxy group of the alkoxyalkyl group includes a methoxy group, an ethoxy group, a propoxy group and the like. Examples of the alkyl group of the alkoxyalkyl group include methyl group, ethyl group, trimethyl group, propyl group, butyl group, tetramethyl group, pentyl group and hexyl group.
In the formula, ^R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom.
Alkyl groups and alkoxyalkyl groups are the same as those of R.
The number of carbon atoms in the acyloxy group is preferably 1-9, more preferably 1-5. The acyloxy group includes an acetyloxy group, a benzoyloxy group and the like.
Halogen atoms include fluorine, chlorine, bromine, and iodine.

[Aluminum salt hydrate]
In order for the antireflection glass of the present invention to exhibit alkali resistance, the aluminum salt hydrate should be present in the low refractive index layer and the high refractive index layer located above the protective layer and the reflective film (on the viewing side). is required. Furthermore, an aspect in which the aluminum salt hydrate is present in the medium refractive index layer and the medium low refractive index layer positioned below the reflective film (on the side of the glass substrate) is preferable because the alkali resistance is extremely high.
An aluminum salt hydrate is a hydrated compound in which water molecules are added to an aluminum salt in the form of water of crystallization or coordination water. If it is not a hydrate, it may aggregate or sediment during mixing due to poor affinity with other components. In particular, in the case of an anhydride salt having hygroscopic properties, the medium-to-low refractive index composition solution described later reacts with moisture in the air during coating, making it difficult to form a medium-to-low refractive index layer. . In addition, other metal salt hydrates exhibit poor alkali resistance. Aluminum salt hydrates are used for the same reason in other refractive index layers.
Aluminum is a metal that can be coordinated with the binder component, and is presumed to exhibit alkali resistance because aluminum oxide, which is resistant to alkali attack, is formed in the refractive index layer.
Aluminum salt hydrates typically include aluminum chloride trihydrate, aluminum chloride hexahydrate, aluminum bromide hexahydrate, aluminum nitrate hexahydrate, aluminum nitrate nonahydrate, aluminum hydroxide trihydrate, Aluminum acetate n-hydrate, aluminum sulfate n-hydrate and the like can be mentioned, and aluminum chloride trihydrate and aluminum chloride hexahydrate are particularly preferred from the standpoint of developing alkali resistance and scratch resistance.
When aluminum salt hydrate is contained in the medium-to-low refractive index layer, the content is 3 to 25 parts by mass with respect to 100 parts by mass of the alkoxysilane compound or the like. If it is less than 3 parts by mass, the effect is not obtained. If it exceeds 25 parts by mass, the bonding strength of the alkoxysilane compound and the like and the hardness of the medium-to-low refractive index layer are lowered, which is not preferable.

[Metal chelate compound]
It is a component that functions as a cross-linking agent and makes the formed refractive index layer more dense.
The metal chelate compound (C) is a compound in which a chelating agent, typically a bidentate ligand, is coordinated to a metal such as titanium, zirconium or aluminum.
Specifically, triethoxy mono (acetylacetonate) titanium, diethoxy bis (acetylacetonate) titanium, monoethoxy tris (acetylacetonate) titanium, tetrakis (acetylacetonate) titanium, triethoxy mono (ethylacetonate) Acetate) titanium, diethoxy bis(ethylacetoacetate) titanium, monoethoxy tris(ethylacetoacetate) titanium, mono(acetylacetonate) tris(ethylacetoacetate) titanium, bis(acetylacetonate) bis(ethylacetoacetate) titanium ) titanium chelate compounds such as titanium, tris(acetylacetonate)mono(ethylacetoacetate)titanium;
Triethoxy mono(acetylacetonate) zirconium, diethoxy bis(acetylacetonate) zirconium, monoethoxy tris(acetylacetonate) zirconium, tetrakis(acetylacetonate) zirconium, triethoxy mono(ethylacetoacetate) zirconium, diethoxy・Bis(ethylacetoacetate) zirconium, monoethoxy tris(ethylacetoacetate) zirconium, tetrakis(ethylacetoacetate) zirconium, mono(acetylacetonate) tris(ethylacetoacetate) zirconium, bis(acetylacetonate) bis( zirconium chelate compounds such as ethylacetoacetate)zirconium, tris(acetylacetonate)mono(ethylacetoacetate)zirconium;
Diethoxy mono (acetylacetonate) aluminum, monoethoxy bis (acetylacetonate) aluminum, di-i-propoxy mono (acetylacetonate) aluminum, monoethoxy bis (ethylacetoacetate) aluminum, diethoxy mono ( and aluminum chelate compounds such as ethylacetoacetate)aluminum and tris(acetylacetonate)aluminum.
The metal chelate compound is used in an amount of 1 to 20 parts by weight, preferably 3 to 15 parts by weight, per 100 parts by weight of the alkoxysilane compound (B). If it exceeds 20 parts by mass, the metal chelate compound tends to precipitate in the medium-to-low refractive index layer, resulting in deterioration of antireflection performance and poor appearance. If the amount is less than 1 part by mass, the strength and hardness of the medium-to-low refractive index layer tend to decrease.

[Silica particles]
In the medium to low refractive index layer of the present invention, silica particles are used to control the refractive index to 1.36-1.45. As the silica particles, the following two types of silica particles, solid silica particles and hollow silica particles, are used.
Solid silica particles are typically composed mainly of silicon dioxide, have a density of 1.9 or more, an average particle size of 5 to 500 nm, and a refractive index of 1.44 to 1.5. These are particles that do not have cavities inside. In the present invention, the average particle size refers to the particle size when the cumulative volume is 50% in the particle size distribution measured by the laser diffraction/scattering method.
Hollow silica particles are particles made of silicon dioxide having cavities inside, and are usually fine hollow particles having a particle size of 5 to 150 nm and an outer shell layer having a thickness of about 1 to 15 nm. Ion exchange is performed using the internal cavity, and it is also a component for forming a layer with a refractive index of 1.36 to 1.45 and exhibiting excellent antireflection performance. Therefore, it is preferable to select hollow silica particles having a refractive index in the range of 1.20 to 1.38.
The hollow silica particles are known, for example, from Japanese Patent Application Laid-Open No. 2001-233611. should be obtained and used.
The silica particles are 25 to 90 parts by mass, preferably 25 to 60 parts by mass of the solid silica particles and 0 to 30 parts by mass of the hollow silica particles, based on 100 parts by mass of the (B) alkoxysilane compound, etc. Considering changes in the refractive index due to thermal history, the refractive index balance between the medium refractive index layer and the high refractive index layer, etc., the material is appropriately selected and used so as to satisfy the predetermined refractive index. In particular, inclusion of solid silica particles is preferable from the viewpoint of suppressing shrinkage of the alkoxysilane compound or the like due to thermal history.

[Medium-low refractive index layer-forming solution]
Each of the above components constituting the medium-low refractive index layer is dissolved in the following organic solvent for the purpose of viscosity adjustment and easy coating in addition to optional components as necessary to form the medium-low refractive index layer. It is used as a solution for forming a layer. In order to promote hydrolysis and condensation of the alkoxysilane compound and the like, an appropriate amount of an aqueous acid solution such as an aqueous hydrochloric acid solution can be added to the solution.
Representative organic solvents include alcohol solvents such as methanol, ethanol, isopropanol, ethyl cellosolve, and ethylene glycol; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone and methyl ethyl ketone; Aromatic solvents are used. Alcoholic solvents are particularly preferred. When a commercially available silica particle dispersion is used, the dispersion medium is inevitably mixed into the medium-to-low refractive index layer-forming solution. The dispersion medium in the solution and the separately blended organic solvent are removed in the subsequent drying and heat-curing steps.
The amount of the organic solvent to be used may be such that the viscosity of the forming solution does not cause sagging, etc., and is within a range suitable for coating. Generally, the organic solvent should be used in such an amount that the total solids concentration is 0.1 to 20% by weight of the total weight. The amount of organic solvent is a value including the amount of dispersion medium such as silica particles.

[Formation of medium-low refractive index layer]
The medium-to-low refractive index layer-forming solution is applied onto the glass substrate, dried, and then cured by heating to form the medium-to-low refractive index layer. However, the heat-curing step by heating can be performed collectively after coating and drying the medium refractive index layer, high refractive index layer and low refractive index layer described later in the same manner. is preferable from the viewpoint of adhesion of Furthermore, it is particularly preferable to heat and cure all layers of the antireflection film and the protective layer at once after applying and drying the protective layer in the same manner.
The coating method is not particularly limited, and methods such as dip coating, roll coating, die coating, flow coating, and spraying are employed, but the dip coating method is preferable from the viewpoint of appearance quality and layer thickness control. .
Drying is usually carried out in the atmosphere at a temperature of 70 to 100° C. for 0.25 to 1 hour. Heating for thermosetting is usually carried out at 300 to 500° C. in the atmosphere for 0.5 to 2 hours.

<Medium refractive index layer>
It is a refractive index layer laminated on the medium-to-low refractive index layer (visual field side).
The medium refractive index layer has a refractive index of 1.56 to 1.79 and a layer thickness of 90 to 140 nm. Preferably, the refractive index is between 1.58 and 1.76 and the layer thickness is between 95 and 135 nm.

Since the medium refractive index layer needs to be glass-strengthened by chemical treatment after the formation of the antireflection film and the protective layer, a solution of the medium refractive index layer composition containing the following components is prepared, and the solution is coated and dried. , is preferably formed by heating.
(B) With respect to 100 parts by mass of a binder component composed of an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof (hereinafter referred to as "alkoxysilane compound, etc."),
R _n —Si(OR ¹ ) _4-n (1)
(wherein R is an alkyl group, an alkenyl group or an alkoxyalkyl group, ^R1 is an alkyl group, an alkoxyalkyl group, an acyloxy group or a halogen atom, and n is an integer of 1 or 2)
(A) 1 to 15 parts by mass of aluminum salt hydrate, and (E) 40 to 130 parts by mass of metal oxide particles, when (A) aluminum salt hydrate is not contained in the medium refractive index layer (A) the aluminum salt hydrate may be excluded from the composition.

[Alkoxysilane compound or its hydrolyzate]
It is a compound represented by the formula (1) and is as described in the section of the medium-low refractive index layer. An alkoxysilane compound or the like used for forming a medium-to-low refractive index layer can be similarly used for the same purpose.

[Aluminum salt hydrate]
In the present invention, the aluminum salt hydrate, which is a component that contributes to the development of alkali resistance, is preferably present in the medium refractive index layer as well as in the medium low refractive index layer. The aluminum salt hydrates used to form the medium and low refractive index layers can be used as well.
When aluminum salt hydrate is contained in the medium refractive index layer, it is contained in an amount of 1 to 15 parts by mass based on 100 parts by mass of the alkoxysilane compound and the like. If it is less than 1 part by mass, the effect is not obtained. If it exceeds 15 parts by mass, it is not preferable because it becomes difficult to form a layer due to a tendency to react with moisture in the air during coating.

[Metal oxide particles]
Metal oxide particles are blended in the medium refractive index layer in order to control the refractive index to the predetermined value.
As metal oxide particles, those having a refractive index of 1.50 or more can be used. For example, the group consisting of titanium oxide, zirconium oxide, niobium pentoxide, antimony-doped tin oxide (ATO), indium-tin oxide (ITO), phosphorus-doped tin oxide (PTO), fluorine-doped tin oxide (FTO) and antimony pentoxide. more chosen.
At least one kind of oxide particles is preferred.
Specifically, as the metal oxide particles, zirconium oxide particles (refractive index = 2.40), zirconium oxide and other oxides such as silicon oxide are combined at the molecular level to adjust the refractive index. Zirconium metal oxide particles, titanium oxide particles (refractive index = 2.71), composite titanium metal oxide in which the refractive index is adjusted by combining titanium oxide with other oxides such as silicon oxide and zirconium oxide at the molecular level particles are used. A desired refractive index is adjusted by appropriately combining these metal oxide particles. Such particles are known per se and commercially available.
The average particle size of the metal oxide particles is preferably 1-100 nm, more preferably 1-70 nm. The refractive index of the metal oxide particles is preferably 1.70-2.80, more preferably 1.90-2.50.
The content of the metal oxide particles in the medium refractive index layer composition is 40 to 130 parts by mass, preferably 40 to 90 parts by mass of zirconium oxide particles and 0 parts by mass of titanium oxide particles, based on 100 parts by mass of the alkoxysilane compound and the like. It is appropriately selected from the range of up to 40 parts by mass so as to satisfy the predetermined refractive index in consideration of changes in the refractive index due to thermal history. In particular, inclusion of zirconium oxide particles is preferable from the viewpoint of suppressing shrinkage of the alkoxysilane compound due to thermal history.

[Medium refractive index layer forming solution]
Each of the components constituting the medium-low refractive index layer is dissolved in an optional component such as an acid aqueous solution, if necessary, and the organic solvent to form a solution for forming a medium-refractive index layer.

[Formation of Middle Refractive Index Layer]
The medium refractive index layer-forming solution is applied onto the medium-low refractive index layer, dried, and then cured by heating to form the medium refractive index layer.
The coating method, drying conditions, heating conditions, etc. conform to the method for forming the medium-to-low refractive index layer. Similarly, the thermosetting step by heating may be performed collectively after the application and drying of the four layers constituting the antireflection film, or further after the application and drying of the protective layer. is preferable from the viewpoint of

<High refractive index layer>
It is a refractive index layer laminated on the medium refractive index layer (viewing side) and has a higher refractive index than the medium refractive index layer.
The high refractive index layer has a refractive index of 1.75 to 1.87 and a layer thickness of 30 to 50 nm. Preferably, the refractive index is 1.77-1.85 and the layer thickness is 35-45 nm

Since the high refractive index layer needs to be strengthened by chemical treatment after forming the antireflection film and the protective layer, a solution of a high refractive index layer composition containing the following components is prepared, the solution is coated, and dried. , is preferably formed by heating.
(B) With respect to 100 parts by mass of a binder component composed of an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof (hereinafter referred to as "alkoxysilane compound, etc."),
R _n —Si(OR ¹ ) _4-n (1)
(wherein R is an alkyl group, an alkenyl group or an alkoxyalkyl group, ^R1 is an alkyl group, an alkoxyalkyl group, an acyloxy group or a halogen atom, and n is an integer of 1 or 2)
(A) 1 to 15 parts by mass of aluminum salt hydrate, and (E) 40 to 130 parts by mass of metal oxide particles. The presence of aluminum salt hydrate is required.

[Aluminum salt hydrate]
The aluminum salt hydrate, which is a component that contributes to the development of alkali resistance in the present invention and must be present in the high refractive index layer as well as the low refractive index layer and the protective layer. As the aluminum salt hydrate used for forming the medium-to-low refractive index layer can be used as well.
The content of the aluminum salt hydrate in the high refractive index layer is 1 to 15 parts by mass with respect to 100 parts by mass of the alkoxysilane compound and the like. If it is less than 1 part by mass, the effect is not obtained. If it exceeds 15 parts by mass, it is not preferable because it becomes difficult to form a layer due to a tendency to react with moisture in the air during coating.

[Metal oxide particles]
Metal oxide particles are blended in the high refractive index layer in order to control the refractive index to the predetermined value.
As the metal oxide particles, the metal particles used for forming the medium refractive index layer are similarly used.
The content of the metal oxide particles in the high refractive index layer composition is 40 to 130 parts by mass, preferably 0 to 40 parts by mass of the zirconium oxide particles and 40 parts by mass of the titanium oxide particles, based on 100 parts by mass of the alkoxysilane compound and the like. It is appropriately selected from the range of up to 90 parts by mass so as to satisfy the predetermined refractive index in consideration of changes in the refractive index due to thermal history. In particular, it is preferable to contain titanium oxide particles in order to achieve a high refractive index.

[Solution for forming high refractive index layer]
Each of the above components constituting the high refractive index layer is dissolved in an optional component such as an acid aqueous solution, if necessary, and the organic solvent to obtain a solution for forming a high refractive index layer.

[Formation of high refractive index layer]
The high refractive index layer-forming solution is applied onto the medium refractive index layer, dried, and then cured by heating to form a high refractive index layer.
The coating method, drying conditions, heating conditions, etc. conform to the method for forming the medium-to-low refractive index layer. Similarly, the thermosetting step by heating may be performed collectively after the application and drying of the four layers constituting the antireflection film, or further after the application and drying of the protective layer. is preferable from the viewpoint of

<Low refractive index layer>
It is a refractive index layer located on the outermost layer (visual field side) of the antireflection film, and is the layer that contributes most to the antireflection performance.
The low refractive index layer has a refractive index of 1.27 to 1.35 and a layer thickness of 70 to 75 nm. Preferably, the refractive index is between 1.28 and 1.32 and the layer thickness is between 71 and 74 nm.

Since the low refractive index layer needs to be glass-strengthened by chemical treatment after forming the antireflection film and the protective layer, prepare a solution of a low refractive index layer composition containing the following components, coat the solution, and dry it. , is preferably formed by heating.
(B) With respect to 100 parts by mass of a binder component composed of an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof (hereinafter referred to as "alkoxysilane compound, etc."),
R _n —Si(OR ¹ ) _4-n (1)
(wherein R is an alkyl group, an alkenyl group or an alkoxyalkyl group, ^R1 is an alkyl group, an alkoxyalkyl group, an acyloxy group or a halogen atom, and n is an integer of 1 or 2)
(A) 3 to 25 parts by mass of aluminum salt hydrate,
(C) 1 to 20 parts by mass of a metal chelate compound, and (D) 25 to 90 parts by mass of silica particles. The existence of things is necessary.

[Aluminum salt hydrate]
The aluminum salt hydrate, which is a component that contributes to the development of alkali resistance in the present invention and must be present in the low refractive index layer together with the high refractive index layer and the protective layer. As the aluminum salt hydrate used for forming the medium-to-low refractive index layer can be used as well.
The content of the aluminum salt hydrate in the low refractive index layer is 3 to 25 parts by mass with respect to 100 parts by mass of the alkoxysilane compound and the like. If it is less than 3 parts by mass, the effect is not obtained. If it exceeds 25 parts by mass, the bonding strength of the alkoxysilane compound and the like and the hardness of the low refractive index layer are lowered, which is not preferable.

[Metal chelate compound]
A metal chelate used for forming the medium-to-low refractive index layer can be used without any limitation for the same purpose.
The metal chelate compound is used in an amount of 1 to 20 parts by weight, preferably 3 to 18 parts by weight, per 100 parts by weight of the alkoxysilane compound (B). If it exceeds 20 parts by mass, the metal chelate compound tends to precipitate in the low refractive index layer and cause poor appearance. If the amount is less than 1 part by mass, the strength and hardness of the low refractive index layer tend to decrease.

[Silica particles]
Silica particles used for forming the medium-to-low refractive index layer can be used without any limitation for the same purpose.
The silica particles are 25 to 90 parts by mass, preferably 0 to 30 parts by mass of the solid silica particles and 25 to 60 parts by mass of the hollow silica particles, based on 100 parts by mass of the (B) alkoxysilane compound, etc. Considering changes in the refractive index due to heat history, the low refractive index layer is appropriately selected and used so as to satisfy the predetermined refractive index. In particular, inclusion of hollow silica particles is preferable in that a low refractive index can be achieved and high antireflection performance can be achieved.

[Solution for Forming Low Refractive Index Layer]
Each of the above components constituting the low refractive index layer is dissolved in an optional component such as an acid aqueous solution, if necessary, and the organic solvent to form a low refractive index layer forming solution.

[Formation of low refractive index layer]
The low refractive index layer-forming solution is applied onto the high refractive index layer, dried, and then cured by heating to form the low refractive index layer.
The coating method, drying conditions, heating conditions, etc. conform to the method for forming the medium-to-low refractive index layer. Similarly, the thermosetting step by heating may be performed collectively after the application and drying of the four layers constituting the antireflection film, or further after the application and drying of the protective layer. is preferable from the viewpoint of

<Protective layer>
A protective layer is placed on the antireflection film (on the viewing side) to prevent the antireflection film from being damaged by external impacts such as scratches, and also to prevent damage due to ion collisions to the antireflection film during chemical strengthening. be provided.
The protective layer has a refractive index of 1.43 to 1.48 and a layer thickness of 20 to 30 nm. Preferably, the refractive index is between 1.44 and 1.46 and the layer thickness is between 20 and 25 nm.

Since the protective layer needs to be strengthened by chemical treatment after forming the antireflection film and the protective layer, a solution of a protective layer composition containing the following components is prepared, and the solution is coated, dried, and heated. It is preferred to form
(B) With respect to 100 parts by mass of a binder component composed of an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof (hereinafter referred to as "alkoxysilane compound, etc."),
R _n —Si(OR ¹ ) _4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, ^R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 3 to 25 parts by mass of aluminum salt hydrate, and (C) 1 to 20 parts by mass of metal chelate compound In order for the antireflective glass of the present invention to exhibit alkali resistance, the protective layer contains (A) aluminum salt hydrate. The existence of things is necessary.

[Aluminum salt hydrate]
The aluminum salt hydrate, which is a component that contributes to the development of alkali resistance in the present invention and must be present in the protective layer as well as in the low refractive index layer and the high refractive index layer. As the aluminum salt hydrate used for forming the medium-to-low refractive index layer can be used as well.
In the protective layer, the content of the aluminum salt hydrate is 3 to 25 parts by mass with respect to 100 parts by mass of the alkoxysilane compound and the like. If it is less than 3 parts by mass, the effect is not obtained. If the amount exceeds 25 parts by mass, the bonding strength of the alkoxysilane compound and the like and the hardness of the protective layer are lowered, which is not preferable.

[Metal chelate compound]
A metal chelate used for forming the medium-to-low refractive index layer can be used without any limitation for the same purpose.
The metal chelate compound is used in an amount of 1 to 20 parts by weight, preferably 3 to 18 parts by weight, per 100 parts by weight of the alkoxysilane compound (B). If it exceeds 20 parts by mass, the metal chelate compound tends to precipitate in the protective layer and cause poor appearance. If the amount is less than 1 part by mass, the strength and hardness of the protective layer are lowered, and the chemical strengthening treatment of the glass substrate tends to be insufficient.

[Solution for Forming Protective Layer]
Each of the above components constituting the protective layer is dissolved in an optional component such as an acid aqueous solution, if necessary, and the above organic solvent to form a protective layer forming solution.

[Formation of protective layer]
The protective layer-forming solution is coated on the low refractive index layer, dried, and then cured by heating to form a protective layer.
The coating method, drying conditions, heating conditions, etc. conform to the method for forming the medium-to-low refractive index layer. From the viewpoint of productivity and the properties of the obtained antireflection film, the heat curing step by heating is preferably carried out collectively after the application and drying of the four layers constituting the antireflection film, followed by the application and drying of the protective layer.

<Glass strengthening by chemical treatment>
The antireflection glass of the present invention is glass-strengthened by chemical treatment. By selecting the compositional components of each of the four layers constituting the antireflection film, as described above, the internal spaces of the particles and the interstitial spaces between the particles are simultaneously used for ion exchange to strengthen the glass.
As a chemical treatment method, a conventionally known method is employed. Typically, an unstrengthened antireflection glass is brought into contact with a metal salt melt of a potassium salt such as potassium nitrate at a temperature in the range of 390° C. to 450° C. for 3 to 16 hours to convert sodium ions having a small ionic radius into ions. A high-strength tempered glass is obtained by replacing potassium ions with large radii.

<Alkaline cleaning>
In the pre-process or post-process of the glass strengthening process, for the purpose of removing organic and inorganic substances adhering to the glass surface, the purpose of preventing the glass from becoming frosted and losing transparency (preventing burning), and other reasons, Alkaline cleaning is performed.
Alkaline cleaning is commercially available as an alkaline cleaning solution with a pH of about 12 to 13, which is obtained by dissolving a strong alkaline compound such as sodium hydroxide or potassium hydroxide, or a surfactant in an alcohol solvent or water. The cleaning solution is appropriately diluted with water or the like according to the conditions.
Alkaline cleaning is usually carried out at room temperature to 55° C. for about 0.1 to 0.5 hours, and then washed with water or an organic solvent to wash off the alkaline cleaning solution.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. Also, not all combinations of features described in the embodiments are essential for the solution of the present invention.
Various components, abbreviations, and test methods used in the following examples and comparative examples are as follows.

(A) Aluminum salt hydrate AlCl _3.6H ₂ O: Aluminum chloride hexahydrate Al(NO ₃ ) 3.9H ₂ O: Aluminum nitrate nonahydrate (B) Alkoxysilane compounds, etc. TEOS: Tetraethoxysilane ₍ C) Metal chelate compound AlTA: Tris (acetylacetonate) aluminum (D) silica particles Hollow silica particles Average particle size: 40 nm, refractive index: 1.25, solid content 20% by weight,
Dispersion solvent: IPA
Solid silica particles Average particle size: 7 nm, refractive index: 1.45, solid content 20% by weight,
Dispersion solvent: IPA
(E) Metal oxide particles Zirconium oxide particles Average particle size: 61.9 nm, refractive index: 2.40, solid content: 30% by weight,
Dispersion solvent: Methanol Titanium oxide particles:
Average particle size: 108.8 nm, refractive index: 2.71, solid content: 15% by weight,
Dispersion solvent: Methanol (organic solvent)
IPA: isopropyl alcohol Ethacol: ethyl alcohol/isopropyl alcohol mixture NPA: normal propyl alcohol SBAC: s-butyl acetate (hydrolysis catalyst)
HCl: 0.05N hydrochloric acid (glass substrate)
Soda lime silicate glass (50 mm x 88 mm x 1.1 mm)
(other metal salt hydrates)
Ni(NO ₃ ) 2.6H ₂ O: Nickel nitrate hexahydrate Co(NO ₃ ) _2.6H ₂ O: _Cobalt nitrate hexahydrate

[Refractive index of each refractive index layer]
Each refractive index layer-forming solution was coated on a glass substrate to a thickness of 100 nm and cured to form each refractive index layer or protective layer. The reflectance of each layer was measured using a "spectrophotometer V-650" manufactured by JASCO Corporation to calculate the refractive index.

[Double-sided luminous average reflectance]
The average luminous reflectance of both surfaces (hereinafter also referred to as average luminous reflectance) was measured by the following method.
Measured at 380 nm to 780 nm using "UV-visible spectrophotometer V-650" manufactured by JASCO Corporation, and calculated by multiplying the weight coefficient based on JIS Z 8722. The object to be measured is an antireflection glass in which an antireflection film and a protective film are formed on both sides of a glass substrate. It should be noted that these measured values are the values of the antireflection glass before tempering the glass, but it was confirmed that these values after tempering the glass hardly changed.

[Average luminous transmittance]
The visual average transmittance was measured by the following method. Measured at 380 nm to 780 nm using "UV-visible spectrophotometer V-650" manufactured by JASCO Corporation, and calculated by multiplying the weight coefficient based on JIS Z 8722. It should be noted that these measured values are the values of the antireflection glass before tempering the glass, but it was confirmed that these values after tempering the glass hardly changed.

[Alkali resistance of antireflection film]
In order to examine the alkali resistance of the antireflection film due to alkali washing, the change in color of the antireflection glass plate before and after alkali washing was observed with the naked eye and evaluated according to the following criteria. The base anti-reflective glass (uncured) color is clear and colorless. The evaluation was performed on the antireflection tempered glass after tempering. “Before tempering” means the alkali resistance when the glass is washed with alkali before tempering, and “after tempering” means the alkali resistance when the glass is tempered and then washed with alkali. indicates that the antireflection film is not optically altered by alkali washing. "X" indicates that the antireflection film was clearly peeled off.
◎: No change ○: Color slightly changed (slightly colored)
△: Color changed (became darker)
×: film peeling occurred

[Glass strength; compression stress value measurement]
Using "FSM-6000LE" manufactured by Orihara Seisakusho Co., Ltd., the surface stress CS (MPa) and stress layer depth DOL (μm) due to the refractive index difference (due to ion substitution) of the chemically strengthened glass surface were measured. Higher CS and DOL values indicate greater reinforcement. If the DOL value is about 10 μm, it functions sufficiently as a tempered glass.

[Preparation of medium-low refractive index layer-forming solution]
The components shown in Tables 1 and 2 were mixed in the amounts shown in the same tables to prepare medium-to-low refractive index layer-forming solutions (ML-1 to ML-9).
ML-6 is a solution containing no (A) aluminum salt hydrate, and ML-8 and 9 are solutions containing metal salt hydrates other than aluminum.

[Preparation of medium refractive index layer forming solution]
The components shown in Tables 3 and 4 were mixed in the amounts shown in the same tables to prepare medium refractive index layer-forming solutions (M-1 to M-7).
M-4 is a solution containing no (A) aluminum salt hydrate, and M-6 and 7 are solutions containing metal salt hydrates other than aluminum.

[Preparation of Solution for Forming High Refractive Index Layer]
The components shown in Tables 5 and 6 were mixed in the amounts shown in the same tables to prepare high refractive index layer-forming solutions (H-1 to H-9).
H-6 is a solution containing no (A) aluminum salt hydrate, and H-8 and 9 are solutions containing metal salt hydrates other than aluminum.

[Preparation of Solution for Forming Low Refractive Index Layer]
The components shown in Tables 7 and 8 were mixed in the amounts shown in the same tables to prepare low refractive index layer forming solutions (L-1 to L-9).
L-6 is a solution containing no (A) aluminum salt hydrate, and L-8 and 9 are solutions containing metal salt hydrates other than aluminum.

[Preparation of Protective Layer Forming Solution]
Components shown in Table 9 were mixed in the amounts shown in the same table to prepare protective layer forming solutions (Co-1 to Co-5).
Co-2 is a solution containing no (A) aluminum salt hydrate, and Co-4 and 5 are solutions containing metal salt hydrates other than aluminum.

Example 1
The aluminosilicate glass (glass substrate) is dipped in a solution for forming a medium-low refractive index layer (ML-6) and then dried at 100° C. for 15 minutes to form an uncured medium-low refractive index layer having a layer thickness of 197 nm. It was formed on a glass substrate. It is thought that the medium-to-low refractive index layer is in an insufficiently cured state due to drying under the above conditions, and the following layers are the same. In addition, the layer thickness was adjusted by the pulling speed from the dipped medium-low refractive index layer forming solution. The same applies to each of the following layers.
Next, the glass substrate is dipped in the medium refractive index layer forming solution (M-4), dried at 100 ° C. for 15 minutes, and an uncured medium refractive index layer having a layer thickness of 109 nm is formed. formed on the layer.
Next, the glass substrate is dipped in the solution for forming a high refractive index layer (H-1), dried at 100° C. for 15 minutes, and an uncured high refractive index layer having a layer thickness of 36 nm is formed into an uncured medium refractive index layer. formed above.
Next, the glass substrate is dipped in the low refractive index layer forming solution (L-1), dried at 100 ° C. for 15 minutes, and an uncured low refractive index layer having a layer thickness of 75 nm is replaced with an uncured high refractive index layer. formed above.
Next, the glass substrate was dipped in the protective layer forming solution (Co-1) and dried at 100° C. for 15 minutes to form an uncured protective layer having a layer thickness of 25 nm on the uncured low refractive index layer. .
The glass substrate laminated with the uncured antireflection film and the protective layer was heated at 500° C. for 30 minutes for thermal curing to prepare the antireflection glass of the present invention. The average luminous reflectance and the average luminous transmittance of both surfaces of the obtained antireflection glass were measured according to the method described above, and are shown in Table 10 together with the layer thickness and refractive index of each layer.
Further, the antireflection glass was washed with alkali and strengthened by the following two methods.
On the other hand, the antireflection glass was first immersed in a diluted solution obtained by diluting "Semi-clean MG; pH = 12.4" manufactured by Yokohama Yushi Kogyo Co., Ltd. by 5 wt% with water at 40°C for 10 minutes under ultrasonic waves. Alkaline cleaning was performed, and then the cleaning liquid was washed away with warm water and IPA. Then, the glass was immersed in a potassium nitrate melt at 410° C. for 3 hours for chemical strengthening treatment to obtain an antireflection tempered glass. The other glass was first subjected to chemical strengthening treatment under the same conditions, and then washed with an alkali under the same conditions to obtain an antireflection tempered glass.
The glass strength and the alkali resistance of the antireflection film after alkali washing of the above two types of antireflection tempered glasses were measured according to the methods described above. The results are shown in Table 10.

Examples 2-9
Two types of antireflection tempered glass were produced in the same manner as in Example 1, except that each refractive index layer forming solution and protective layer forming solution were used in the combinations shown in Table 10.
Table 10 shows the average luminous reflectance and average luminous transmittance of both sides of the antireflection tempered glass, the layer thickness and refractive index of each layer, the glass strength of the antireflection tempered glass, and the alkali resistance of the antireflection film. .
The antireflection tempered glasses (Examples 2 to 6 and 8) containing aluminum chloride hexahydrate in all layers of the antireflection film and protective layer exhibit sufficient glass strength and excellent alkali resistance. When aluminum chloride hexahydrate does not exist in the medium-low refractive index layer and the medium refractive index layer (Example 1), when aluminum chloride hexahydrate does not exist in the medium refractive index layer (Example 7), the antireflection film and When aluminum nitrate nonahydrate was contained in all layers of the protective layer (Example 9), although the color changed slightly, sufficient alkali resistance was exhibited.

Comparative Examples 1-10
Two types of antireflection tempered glass were produced in the same manner as in Example 1, except that each refractive index layer forming solution and protective layer forming solution were used in the combinations shown in Table 11.
Table 11 shows the average luminous reflectance and average luminous transmittance of both sides of the antireflection glass, the layer thickness and refractive index of each layer, the glass strength of the antireflection tempered glass, and the alkali resistance of the antireflection film. rice field.
Comparative Example 1 is a case where no aluminum salt hydrate is present in the entire antireflection film and protective layer, and the alkali resistance is extremely poor. Comparative Example 2 is a case where no aluminum salt hydrate is present in the high refractive index layer, the medium refractive index layer and the medium low refractive index layer, and the alkali resistance is extremely poor.
Comparative Example 3 is a case where no aluminum salt hydrate is present in the low refractive index layer, the medium refractive index layer, and the medium low refractive index layer, and the alkali resistance is poor. Comparative Example 4 is a case in which no aluminum salt hydrate is present in the protective layer, the medium refractive index layer, and the medium to low refractive index layer, and the alkali resistance is poor.
Comparative Examples 5 and 6 are cases where the layer thickness of the refractive index layer does not satisfy the range of the present invention, and the alkali resistance is good, but the optical properties of the average luminous reflectance and the average luminous transmittance are inferior.
Comparative Examples 7 and 8 are cases where the refractive index of the refractive index layer does not satisfy the range of the present invention, and the alkali resistance is good, but the optical properties of the average luminous reflectance and the average luminous transmittance are inferior.
Comparative Examples 9 and 10 are cases where metal salt hydrates other than aluminum salt hydrates are used for all layers of the antireflection film and the protective layer, and the alkali resistance is extremely poor.

Claims

An antireflection glass comprising a glass substrate, an antireflection film and a protective layer in this order,
The antireflection film, from the glass substrate side,
a medium-to-low refractive index layer having a refractive index of 1.36 to 1.45 and a layer thickness of 150 to 210 nm;
a medium refractive index layer having a refractive index of 1.56 to 1.79 and a layer thickness of 90 to 140 nm;
a high refractive index layer having a refractive index of 1.75 to 1.87 and a layer thickness of 30 to 50 nm;
A low refractive index layer having a refractive index of 1.27 to 1.35 and a layer thickness of 70 to 75 nm.
The protective layer has a refractive index of 1.43 to 1.48 and a layer thickness of 20 to 30 nm,
The high refractive index layer, the low refractive index layer and the protective layer contain (A) an aluminum salt hydrate,
The antireflection glass having an average luminous reflectance of 0.6% or less on both surfaces at a wavelength of 380 to 780 nm and an average luminous transmittance of 98% or more at a wavelength of 380 to 780 nm.
The antireflection glass according to claim 1, wherein the medium-low refractive index layer and the medium refractive index layer further contain (A) an aluminum salt hydrate.
With respect to 100 parts by mass of a binder component in which the protective layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R n —Si(OR 1 ) 4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
2. The protective layer composition according to claim 1, comprising a cured product of a protective layer composition containing (A) 3 to 25 parts by mass of an aluminum salt hydrate and (C) 1 to 20 parts by mass of a metal chelate compound. Anti-reflective glass.
With respect to 100 parts by mass of a binder component in which the low refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R n —Si(OR 1 ) 4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 3 to 25 parts by mass of aluminum salt hydrate, (C) 1 to 20 parts by mass of metal chelate compound, and (D) 25 to 90 parts by mass of silica particles. The antireflection glass according to claim 1, characterized by comprising:
With respect to 100 parts by mass of a binder component in which the high refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R n —Si(OR 1 ) 4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(1) It comprises a cured product of a high refractive index layer composition containing (A) 1 to 15 parts by mass of aluminum salt hydrate and (E) 40 to 130 parts by mass of metal oxide particles. The anti-reflection glass described in .
With respect to 100 parts by mass of a binder component in which the medium refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R n —Si(OR 1 ) 4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 1 to 15 parts by mass of aluminum salt hydrate, and (E) 40 to 130 parts by mass of metal oxide particles. The anti-reflection glass described in .
With respect to 100 parts by mass of a binder component in which the medium-to-low refractive index layer is (B) an alkoxysilane compound represented by the following formula (1) or a hydrolyzate thereof,
R n —Si(OR 1 ) 4-n (1)
(Wherein, R is an alkyl group, alkenyl group or alkoxyalkyl group, R1 is an alkyl group, alkoxyalkyl group, acyloxy group or halogen atom, and n is an integer of 1 or 2.)
(A) 3 to 25 parts by mass of aluminum salt hydrate, (C) 1 to 20 parts by mass of a metal chelate compound, and (D) 25 to 90 parts by mass of silica particles. 3. The antireflection glass according to claim 2, which is made of a cured product.
The antireflection glass according to claim 1 or 2, wherein the glass substrate is alkali aluminosilicate glass.
The antireflection glass according to claim 1 or 2, wherein the antireflection glass is alkali-resistant antireflection glass for chemical strengthening.
The antireflection glass according to claim 1 or 2 is subjected to a chemical strengthening treatment in an ion-exchange metal salt melt, and a step of alkali cleaning before or after the chemical treatment. A method for producing antireflection tempered glass.