glass body

Abstract

To provide a glass body that functions as a semi-transparent mirror and can prevent fogging.SOLUTION: A glass body according to the present invention comprises: a glass plate that has a first surface and a second surface on the opposite side of the first surface; a semi-transmissive reflection film that is arranged on the first surface of the glass plate; and anti-fogging means that is arranged on one of the semi-transmissive reflection film and the second surface of the glass plate.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a glass body.

Background Art

[0002] Patent Document 1 discloses a glass body called a so-called half mirror. This glass body is formed by laminating a coating layer containing an inorganic oxide on a glass plate, and the visible light transmittance and visible light reflectance are adjusted. That is, when looking at the glass body from one side, an image is reflected like a mirror, while the light from the image on the other side of the glass body is transmitted and can be seen from the one side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above-mentioned half mirror is used in various applications, and its applications are also expanding. For example, it can be considered to be used as a glass body that partitions the outdoors and the indoors. In this case, there is a possibility that fogging may occur on the surface of the glass body due to the temperature difference between the outdoors and the indoors, and the suppression and removal thereof become problems. The present invention has been made to solve the above problems, and an object thereof is to provide a glass body that can function as a half mirror and suppress fogging.

Means for Solving the Problems

[0005] Item 1. A glass plate having a first surface and a second surface opposite to the first surface, ) A semi-transmissive reflection film disposed on the first surface of the glass plate, An anti-fogging means disposed on at least one of the semi-transmissive reflection film or the second surface of the glass plate, A glass body equipped with these features.

[0006] Item 2. The anti-fog means comprises an anti-fog film, The glass body according to item 1, wherein the anti-fogging film is provided on the second surface of the glass plate.

[0007] Item 3. The glass body according to Item 2, wherein the surface roughness Ra of the semi-transparent reflective film is 15 nm or less.

[0008] Item 4. The glass plate is float glass, The glass body according to item 3, wherein the concentration of tin oxide on the first surface is lower than the concentration of tin oxide on the second surface.

[0009] Item 5. The anti-fog means comprises an anti-fog film, The glass body according to item 1, wherein the anti-fogging film is provided on the semi-transparent reflective film.

[0010] Item 6. The glass body according to Item 5, wherein the semi-transparent reflective film is formed by laminating a plurality of layers, and the difference in refractive index between the anti-fogging film and the outermost layer of the semi-transparent reflective film adjacent to the anti-fogging film is 0.1 or less.

[0011] Item 7. The glass body according to Item 6, wherein the refractive index of the anti-fogging film is 1.6 or less.

[0012] Item 8. The difference in optical film thickness of the anti-fogging film is 150 nm or more. The glass body according to any one of items 5 to 7, wherein the thickness of the anti-fogging film is 10 μm or more.

[0013] Item 9. The anti-fogging means is, The aforementioned anti-fogging film, A film substrate having a thickness of 10 μm or more that supports the anti-fogging film, The film substrate is provided with an adhesive layer located on the side opposite to the anti-fogging film, for fixing the film substrate to the semi-transparent reflective film. A glass body according to item 5 or 6, comprising:

[0014] Item 10. The glass body according to any one of Items 1 to 9, having a haze ratio of 2% or less.

[0015] Item 11. The glass body according to any one of Items 1 to 10, wherein the antifogging means includes an antifogging film containing a water-absorbing resin.

[0016] Item 12. The glass body according to Item 11, wherein the thickness of the antifogging film is 5 μm or more.

[0017] Item 13. The glass body according to any one of Items 1 to 12, having a visible light transmittance of 20% or more and​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ Item 20. The anti-fog means comprises an anti-fog film, The glass body according to item 19, wherein the anti-fogging film is provided on the semi-transparent reflective film.

[0025] Item 21. The anti-fog means comprises an anti-fog film, The glass body according to any one of claims 1 to 20, wherein the surface of the anti-fogging film is subjected to a water-repellent treatment.

[0026] Item 22. The glass body according to Item 21, wherein the water contact angle of the surface of the anti-fogging film is 70° or more.

[0027] Item 23. The anti-fogging means is disposed on the semi-transparent reflective film and on the second surface of the glass plate, according to any one of items 1 to 9.

[0028] Item 24. The glass body according to any one of items 1 to 23, further comprising a light-shielding film formed on at least one of the anti-fogging means and the semi-transparent reflective film. [Effects of the Invention]

[0029] According to the present invention, it is possible to suppress fogging while functioning as a half-mirror. [Brief explanation of the drawing]

[0030] [Figure 1] This is a plan view showing one embodiment of a glass body according to the present invention. [Figure 2] This is a cross-sectional view along line AA in Figure 1. [Figure 3] Figure 1 is a plan view showing an example of an environment in which the glass material is used. [Figure 4] This is a cross-sectional view showing another example of a glass body according to the present invention. [Figure 5] This is a plan view showing another example of a glass body according to the present invention. [Figure 6] Figure 5 is a cross-sectional view along line BB. [Modes for carrying out the invention]

[0031] Hereinafter, an embodiment of the glass body according to the present invention will be described with reference to the drawings. Figure 1 is a plan view of the glass body, Figure 2 is a cross-sectional view of line AA in Figure 1, and Figure 3 is a plan view showing an example of an environment in which this glass body is used.

[0032] <1. Overview of the Vitrelle> As shown in Figures 1 and 2, the glass body 10 comprises a glass plate 1 having two main surfaces, a first surface 11 and a second surface 12, a semi-transparent reflective film 2 laminated on the first surface 11, and an anti-fog film 3 laminated on the second surface 12. The semi-transparent reflective film 2 adjusts the visible light transmittance and visible light reflectance of the glass body 10, so the glass body 10 constitutes a so-called half-mirror. For example, as shown in Figure 3, if a first area 61 and a second area 62 are formed with the glass body 10 in between, light from a first image 51 located in the first area 61 is reflected by the surface of the glass body 10, so the first image 51 is projected onto the glass body 10. On the other hand, light from a second image 52 located in the second area 62 is transmitted through the glass body 10, so the second image 52 in the second area 62 can be seen from the first area 61. These will be explained in detail below.

[0033] <1-1. Glass plate> The glass plate 1 is not particularly limited, and any known glass plate can be used. For example, various glass plates such as float glass, heat-absorbing glass, clear glass, green glass, UV green glass, and soda-lime glass can be used. The thickness of the glass plate 1 is not particularly limited, but is preferably 0.5 to 10 mm, and more preferably 0.7 to 8 mm. The thickness of the glass plate 1 affects the visible light transmittance and visible light reflectance mentioned above, and can therefore be appropriately changed according to the required reflectance and transmittance.

[0034] Here, we will explain the case where glass plate 1 is float glass. Float glass is manufactured by the float process. It is well known that float glass is a glass plate in which the concentration of tin oxide differs on its two main surfaces, due to its manufacturing method. In other words, in the float process, a flat glass plate is manufactured by pouring molten glass onto the surface of molten tin. At this time, a tin oxide-containing layer exists on the surface of the glass plate that is in contact with the molten tin. In a glass plate, the surface in which this tin oxide-containing layer exists is generally called the bottom surface, and the opposite surface that was not in contact with the tin is called the top surface. As will be described later, the tin oxide content on the bottom surface is greater than the tin oxide content on the top surface. Here, the tin oxide content is the maximum concentration of tin oxide converted to tin dioxide in the range from the surface of the glass to a depth of 10 μm. Specifically, this can be determined, for example, based on values ​​measured by a Wavelength Dispersive X-ray Detector (WDX) attached to an Electron Probe Micro Analyzer (EPMA). The tin oxide content on the bottom surface is preferably 1 to 10% by mass, and the tin oxide content on the top surface is preferably 1% or less, and more preferably 0.3% or less.

[0035] When such float glass is used as the glass plate 1, a semi-transparent reflective film 2 can be laminated on the top surface and an anti-fogging film 3 can be laminated on the bottom surface.

[0036] Furthermore, the surface roughness Ra of the glass plate 1 is preferably 10 nm or less. This is because if the surface roughness is high, the haze rate will increase, which may cause clouding.

[0037] <1-2. Semi-transparent reflective film> As shown in Figure 2, the semi-transparent reflective film 2, as an example, has a first layer 21 laminated on a glass plate 1 and a second layer 22 laminated on the first layer 21. However, additional layers such as a third layer and a fourth layer can be provided as needed. When a metal reflective layer made of metal or a metalloid is used as a layer constituting the semi-transparent reflective film 2, one or more units consisting of two layers, in which a low refractive index layer or a high refractive index layer is laminated directly on the metal reflective layer, or one or more units in which a low refractive index layer and a high refractive index layer are laminated in that order on the metal reflective layer can be laminated. When a metal reflective layer is not used, one or more units in which a low refractive index layer and a high refractive index layer are laminated in that order on the high refractive index layer can be laminated. The refractive index of the high refractive index layer is preferably 1.6 or higher, and more preferably 1.8 or higher. The refractive index of the low refractive index layer is lower than this, for example, preferably 1.6 or lower, and more preferably 1.5 or lower. Furthermore, high-refractive-index layers and low-refractive-index layers can also be formed by laminating one or more materials, provided that the refractive index requirements are met.

[0038] Next, the materials of each layer of the semi-transparent reflective film 2 will be described. Each layer constituting the semi-transparent reflective film 2 can be formed by a layer made of a metal or metalloid and a layer made of an inorganic metal oxide, for example, silicon (Si), SUS or another suitable metal or metalloid, silicon dioxide (SiO2), tin oxide (SnO2), titanium dioxide (TiO2), or another suitable inorganic metal oxide, which can be appropriately selected to satisfy the range of refractive indices described above. For example, the refractive indices of silicon, silicon dioxide, tin oxide, titanium dioxide, SUS, Ag, Al, Cr, Mo, and Ti are approximately 4.4, 1.4, 1.8, 2.2, 2.4, 0.14, 1.4, 2.4, 3.6, and 2.7, respectively. The layer configuration of the semi-transparent reflective film 2 is not particularly limited, but for example, it can be as follows. Additives can also be appropriately doped to adjust the electrical resistance of each layer. In addition, Ag, Al, Cr, Ti, or Mo can be used instead of Si in the first layer of Examples 2 and 3. [Table 1]

[0039] In Examples 1 and 3, SiO2 can be provided as an underlayer between the first layer 21 and the glass plate 1. Furthermore, using SUS can improve the visible light absorption rate. When the visible light absorption rate is improved, the sum of the visible light reflectance and visible light transmittance decreases, making it easier to adjust the visible light reflectance and visible light transmittance.

[0040] When a semi-transparent reflective film 2 is formed using an inorganic metal oxide containing the above-described metal or metalloid, the color tone does not change significantly when the semi-transparent reflective film 2 is viewed from a wide angle, making it suitable as an optical cover glass.

[0041] The thickness (physical thickness) of the semi-transparent reflective film 2 is preferably 3 to 300 nm, and more preferably 5 to 250 nm. If the thickness of the semi-transparent reflective film 2 is less than 10 nm, it becomes difficult to control the thickness, resulting in poor productivity. On the other hand, if it exceeds 300 nm, the cost may increase, surface irregularities may become more pronounced, and the haze rate may increase, resulting in an unattractive appearance. Furthermore, the thickness of each layer constituting the semi-transparent reflective film 2 can be appropriately adjusted so that the thickness of the semi-transparent reflective film 2 falls within the above-mentioned range, and is not particularly limited. For example, in Example 2 above, a semi-transparent reflective film can be formed with the first layer at 18 nm, the second layer at 85 nm, and the third layer at 65 nm. In Example 4 above, the silicon thickness can be approximately 18 nm, and the silicon dioxide thickness at approximately 30 nm. In addition, the titanium dioxide thickness in Examples 1 and 3 can be approximately 6 nm, and the SUS thickness in Example 5 can be approximately 8 nm.

[0042] Furthermore, in Example 2, a low-refractive-index material can be laminated in the second layer and a high-refractive-index material in the third layer to enhance the reflection in the first layer. For example, as described above, if the first layer is 18 nm, the second layer is 85 nm, and the third layer is 65 nm, and the optical thickness of the semi-transparent reflective film is set to 135 nm ± 20 nm, the optical thickness becomes λ / 4 for the wavelength of incident light λ (center wavelength: 550 nm), thus strengthening the reflection at the interface between the first and second layers. In this way, materials other than those shown in Example 2 may be used as long as the thickness and refractive index of each layer can be adjusted.

[0043] The visible light transmittance of the glass body 10 provided with the semi-transparent reflective film 2 is preferably 20% to 70%, more preferably 35% to 60%, and particularly preferably 35% to 50%. Since visible light transmittance and visible light reflectance generally have a trade-off relationship, for example, it is preferable that the visible light reflectance and visible light transmittance of the glass body 10 are of equivalent value. However, it is also possible to make either the visible light transmittance or the visible light reflectance greater, and this can be appropriately adjusted according to the required performance of the glass body. For example, it is possible to adjust it so that the visible light reflectance is higher than the visible light transmittance. On the other hand, as a half mirror, the visible light reflectance of the semi-transparent reflective film 2 is preferably 30% to 80%, and more preferably 40% to 70%.

[0044] The visible light transmittance and visible light reflectance of such a glass body 10 can be adjusted by changing the material and film thickness of the semi-transparent reflective film 2, and the material and thickness of the glass plate 1.

[0045] Furthermore, a change in the color of the glass body 10 may be undesirable. Therefore, in the L*, a*, b* color system, the reflected color tone from the semi-transparent reflective film 2 side is preferably within ±15 for both a* and b*, more preferably ±12 or less, and particularly preferably ±7 or less. These a* and b* can be adjusted by changing the material and film thickness constituting the semi-transparent reflective film 2, and the material and thickness of the glass plate 1, similar to the visible light transmittance and visible light reflectance. If a* and b* are within ±15, the reflected light of the image can be displayed correctly. Generally, if a* and b* are between 3.2 and 6.5, it is said that this is the "range in which they can be treated as the same color at the impression level." Furthermore, generally, if a* and b* are 3.2 or less, it is said that this is a color tone level that is hardly noticeable in color separation comparisons.

[0046] The optical properties of the semi-transparent reflective film of Example 4 above are shown below. The first layer of silicon had a thickness of 18 nm, and the silicon dioxide layer had a thickness of 30 nm. Visible light transmittance and visible light reflectance were measured using a spectrophotometer (Hitachi U4100). L*, a*, and b* were calculated according to JIS Z8781. The light source was D65. The results are as follows. [Table 2]

[0047] Based on the optical properties described above, the color tones a* and b* in reflection are 6.5 or less. Furthermore, the color tone b* in transmission is larger. Therefore, the color tone of reflection is more neutral than that of transmission.

[0048] Furthermore, it is preferable that the thermal conductivity of the semi-transparent reflective film 2 is greater than that of the glass plate 1. This allows for a smaller temperature difference within the surface compared to the glass plate 1, thereby preventing localized condensation. Since the thermal conductivity of the glass plate 1 is 0.55 to 1.00 [W / m·K], it is preferable that the thermal conductivity of the semi-transparent reflective film 2 is greater than this, specifically 1.2 to 200 [W / m·K].

[0049] Furthermore, the surface roughness Ra of the semi-transparent reflective film 2 is preferably 15 nm or less, and more preferably 10 nm or less. This is because if the surface roughness is large, the haze rate will increase, which may cause clouding. Note that the surface roughness Ra of the semi-transparent reflective film 2 refers to the surface roughness Ra when no other layers are laminated on the semi-transparent reflective film 2 and the surface roughness Ra of the semi-transparent reflective film 2 can be measured directly.

[0050] <1-3. Method for forming semi-transparent reflective films> Next, the method for forming the semi-transparent reflective film 2 will be described. The method for forming the semi-transparent reflective film 2 is not particularly limited, but for example, so-called physical vapor deposition methods such as sputtering and vacuum deposition, spraying, or chemical vapor deposition (CVD) can be employed. In particular, when employing the CVD method, it is preferable to employ the online CVD method. The online CVD method is a type of chemical vapor deposition in which, in the float glass manufacturing process, a material for the semi-transparent reflective film is supplied from a coater onto the top surface of a glass ribbon at a temperature of 615°C or higher on a molten tin bath, and the semi-transparent reflective film 2 is formed by a thermal decomposition oxidation reaction.

[0051] To deposit each layer of the semi-transparent reflective film 2, one material can be supplied from one coater. However, if the thickness of the layers is large, one layer can be deposited using two or more coaters. For example, in Example 4 above, if the silicon thickness is 18 nm and the silicon dioxide thickness is 30 nm, the semi-transparent reflective film 2 can be deposited by preparing the first to third coaters, supplying silicon with the first coater, and supplying silicon dioxide with the second and third coaters.

[0052] The SUS mentioned above is deposited by sputtering, not by CVD. Furthermore, sputtering is preferable for depositing thin films.

[0053] <1-4. Anti-fog coating> The anti-fog film 3 is not particularly limited as long as it provides an anti-fog effect on the glass plate 1, and any known type can be used. Generally, anti-fog films 3 include hydrophilic types that form a water film on the surface of water vapor, water-absorbing types that absorb water vapor, water-repellent and water-absorbing types that make it difficult for water droplets to condense on the surface, and water-repellent types that repel water droplets that form from water vapor, and any type of anti-fog film can be applied. Below, as an example, an example of a water-repellent and water-absorbing type anti-fog film will be described. [Organic-inorganic composite anti-fogging film] The organic-inorganic composite anti-fogging film is a single-layer or multi-layer film formed on the surface of a glass plate 1. The organic-inorganic composite anti-fogging film contains at least a water-absorbing resin, water-repellent groups, and a metal oxide component. The anti-fogging film 3 may further contain other functional components as needed. The water-absorbing resin can be any type of resin that can absorb and retain water. The water-repellent groups can be supplied to the anti-fogging film 3 from a metal compound having water-repellent groups (water-repellent group-containing metal compound). The metal oxide component can be supplied to the anti-fogging film 3 from a water-repellent group-containing metal compound, other metal compounds, metal oxide fine particles, etc. The following describes each component.

[0054] (Water absorbent resin) There are no particular restrictions on the water-absorbing resin, and examples include polyethylene glycol, polyether resins, polyurethane resins, starch resins, cellulose resins, acrylic resins, epoxy resins, polyester polyols, hydroxyalkylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetal resin, and polyvinyl acetate. Of these, hydroxyalkylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetal resin, polyvinyl acetate, epoxy resins, and polyurethane resins are preferred, more preferred are polyvinyl acetal resin, epoxy resins, and polyurethane resins, and particularly preferred is polyvinyl acetal resin.

[0055] Polyvinyl acetal resin can be obtained by condensing polyvinyl alcohol with an aldehyde to form an acetal. The acetalization of polyvinyl alcohol can be carried out using known methods such as precipitation using an aqueous medium in the presence of an acid catalyst, or dissolution using a solvent such as alcohol. Acetalization can also be carried out in parallel with the saponification of polyvinyl acetate. The degree of acetalization is preferably 2-40 mol%, more preferably 3-30 mol%, particularly 5-20 mol%, and in some cases 5-15 mol%. For example, the degree of acetalization can be expressed as follows: 13 It can be measured based on 1C nuclear magnetic resonance spectroscopy. Polyvinyl acetal resins with an acetalization degree within the above range are suitable for forming organic-inorganic composite anti-fogging films with good water absorption and water resistance.

[0056] The average degree of polymerization of polyvinyl alcohol is preferably 200 to 4500, and more preferably 500 to 4500. A high average degree of polymerization is advantageous for forming an organic-inorganic composite anti-fogging film with good water absorption and water resistance, but if the average degree of polymerization is too high, the viscosity of the solution may become too high, which may hinder film formation. The degree of saponification of polyvinyl alcohol is preferably 75 to 99.8 mol%.

[0057] Examples of aldehydes to be condensed with polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butyraldehyde, hexylcarbaldehyde, octylcarbaldehyde, and decylcarbaldehyde. Other examples include benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, and other alkyl-substituted benzaldehydes; chlorobenzaldehyde and other halogen-substituted benzaldehydes; substituted benzaldehydes in which hydrogen atoms are substituted by functional groups other than alkyl groups such as hydroxyl, alkoxy, amino, and cyano groups; and aromatic aldehydes such as naphthaldehyde and anthraldehyde, which are condensed aromatic ring aldehydes. Aromatic aldehydes with strong hydrophobicity are advantageous in forming organic-inorganic composite anti-fogging films with a low degree of acetalization and excellent water resistance. The use of aromatic aldehydes is also advantageous in forming highly absorbent films while retaining a large number of hydroxyl groups. It is preferable that the polyvinyl acetal resin contains an acetal structure derived from an aromatic aldehyde, particularly benzaldehyde.

[0058] Examples of epoxy resins include glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidylamine epoxy resins, and cyclic aliphatic epoxy resins. Of these, cyclic aliphatic epoxy resins are preferred.

[0059] Examples of polyurethane resins include those composed of polyisocyanate and polyol. Acrylic polyols and polyoxyalkylene polyols are preferred as polyols.

[0060] The organic-inorganic composite anti-fogging film mainly consists of a water-absorbing resin. In this invention, "main component" means the component with the highest mass content. The weight-based water-absorbing resin content of the organic-inorganic composite anti-fogging film is preferably 50% by weight or more, more preferably 60% by weight or more, particularly preferably 65% ​​by weight or more, and 95% by weight or less, more preferably 90% by weight or less, from the viewpoint of film hardness, water absorption, and anti-fogging properties.

[0061] (Water-repellent group) To fully obtain the above-mentioned effects of the water-repellent group, it is preferable to use a water-repellent group with high water repellency. Preferred water-repellent groups are at least one selected from (1) a chain or cyclic alkyl group having 3 to 30 carbon atoms, and (2) a chain or cyclic alkyl group having 1 to 30 carbon atoms in which at least some of the hydrogen atoms are substituted with fluorine atoms (hereinafter sometimes referred to as "fluorine-substituted alkyl group").

[0062] Regarding (1) and (2), the linear or cyclic alkyl group is preferably a linear alkyl group. The linear alkyl group may be a branched alkyl group, but a linear alkyl group is preferred. Alkyl groups with more than 30 carbon atoms may cause the anti-fogging film 3 to become cloudy. From the viewpoint of balancing the anti-fogging properties, strength, and appearance of the film, the number of carbon atoms in the alkyl group is preferably 20 or less, and more preferably 6 to 14. Particularly preferred alkyl groups are linear alkyl groups with 6 to 14 carbon atoms, especially 6 to 12 carbon atoms, for example, n-hexyl group (6 carbon atoms), n-decyl group (10 carbon atoms), and n-dodecyl group (12 carbon atoms). Regarding (2), the fluorine-substituted alkyl group may be a group in which only some of the hydrogen atoms of a linear or cyclic alkyl group are substituted with fluorine atoms, or it may be a group in which all of the hydrogen atoms of a linear or cyclic alkyl group are substituted with fluorine atoms, for example, a linear perfluoroalkyl group. Because fluorine-substituted alkyl groups have high water repellency, a sufficient effect can be obtained by adding a small amount. However, if the fluorine-substituted alkyl group is present in excessively high concentrations, it may separate from other components in the coating solution used to form the film.

[0063] (Hydrolyzable metal compounds with water-repellent groups) In order to incorporate water-repellent groups into the anti-fogging film 3, it is preferable to add a metal compound having water-repellent groups (water-repellent group-containing metal compound), particularly a metal compound having water-repellent groups and hydrolyzable functional groups or halogen atoms (water-repellent group-containing hydrolyzable metal compound), or its hydrolysate, to the coating solution for forming the film. In other words, the water-repellent groups may be derived from the water-repellent group-containing hydrolyzable metal compound. As the water-repellent group-containing hydrolyzable metal compound, the water-repellent group-containing hydrolyzable silicon compound shown in the following formula (I) is preferred. R m SiY 4-m (I) Here, R is a water-repellent group, i.e., a chain or cyclic alkyl group having 1 to 30 carbon atoms in which at least some of the hydrogen atoms may be substituted with fluorine atoms; Y is a hydrolyzable functional group or halogen atom; and m is an integer from 1 to 3. The hydrolyzable functional group is, for example, at least one selected from alkoxy groups, acetoxy groups, alkenyloxy groups, and amino groups, preferably an alkoxy group, particularly an alkoxy group having 1 to 4 carbon atoms. An alkenyloxy group is, for example, an isopropenoxy group. The halogen atom is preferably chlorine. The functional groups exemplified here can also be used as "hydrolyzable functional groups" as described later. m is preferably 1 to 2.

[0064] When the compound represented by formula (I) undergoes complete hydrolysis and polycondensation, it yields the component represented by the following formula (II). R m SiO (4-m) / 2 (II) Here, R and m are as described above. After hydrolysis and polycondensation, the compound represented by formula (II) actually forms a network structure in the anti-fogging film 3 in which silicon atoms are bonded to each other via oxygen atoms.

[0065] Thus, the compound represented by formula (I) undergoes hydrolysis or partial hydrolysis, and at least a portion of it undergoes polycondensation to form a network structure of siloxane bonds (Si-O-Si) in which silicon atoms and oxygen atoms are alternately linked and spread three-dimensionally. Hydrophobic groups R are attached to the silicon atoms included in this network structure. In other words, the hydrophobic groups R are fixed to the siloxane bond network structure via R-Si bonds. This structure is advantageous for uniformly dispersing the hydrophobic groups R in the film. The network structure may also contain silica components supplied from silicon compounds other than the hydrophobic silicon compound containing hydrolyzable silicon compounds represented by formula (I) (e.g., tetraalkoxysilane, silane coupling agent). When a silicon compound having hydrolyzable functional groups or halogen atoms but lacking hydrophobic groups (hydrophobic silicon compound without hydrophobic groups) is blended with a hydrophobic silicon compound containing hydrolyzable silicon compounds in a coating solution for forming an anti-fogging film 3, a network structure of siloxane bonds containing silicon atoms bonded to hydrophobic groups and silicon atoms not bonded to hydrophobic groups can be formed. With this structure, it becomes easy to independently adjust the content of water-repellent groups and metal oxide components in the anti-fogging film.

[0066] The water-repellent groups improve anti-fogging performance by increasing the permeability of water vapor on the surface of the anti-fogging film 3 containing the water-absorbing resin. Since water absorption and water repellency are mutually exclusive functions, water-absorbing and water-repellent materials have traditionally been applied to separate layers. However, the water-repellent groups eliminate the uneven distribution of water near the surface of the anti-fogging film, extending the time until condensation occurs and improving the anti-fogging properties of the single-layer anti-fogging film. The following explains these effects.

[0067] Water vapor that penetrates the anti-fogging film 3 containing a water-absorbent resin forms hydrogen bonds with the hydroxyl groups of the water-absorbent resin and is retained in the form of bound water. As the amount increases, the water vapor progresses from bound water to semi-bound water and finally to free water held in the voids within the anti-fogging film. In the anti-fogging film 3, water-repellent groups hinder the formation of hydrogen bonds and facilitate the dissociation of formed hydrogen bonds. If the water-absorbent resin content is the same, there is no difference in the number of hydrogen-bonding hydroxyl groups in the film, but water-repellent groups reduce the rate of hydrogen bond formation. Therefore, in the anti-fogging film 3 containing water-repellent groups, moisture will ultimately be retained in the film in one of the above forms, but it can diffuse as water vapor to the bottom of the film before being retained. Also, once retained, water dissociates relatively easily and can easily move to the bottom of the film in the form of water vapor. As a result, the distribution of moisture retention in the thickness direction of the film is relatively uniform from near the surface to the bottom of the film. In other words, by effectively utilizing the entire thickness of the anti-fog film and absorbing water supplied to the film surface, water droplets are less likely to condense on the surface, resulting in improved anti-fog properties. Furthermore, because water droplets are less likely to condense on the surface, the moisture-absorbing anti-fog film 3 has the characteristic of being less likely to freeze even at low temperatures.

[0068] On the other hand, in the anti-fogging film 3, which does not contain water-repellent groups, water vapor that penetrates the film is very easily retained in the form of bound water, semi-bound water, or free water. Therefore, the penetrated water vapor tends to be retained near the surface of the film. As a result, the amount of moisture in the film is extremely high near the surface and decreases rapidly as it moves towards the bottom of the film. In other words, although the bottom of the film can still absorb water, the moisture near the surface of the film becomes saturated and condenses into water droplets, resulting in limited anti-fogging properties.

[0069] When water-repellent groups are introduced into an anti-fogging film using a hydrolyzable silicon compound containing water-repellent groups (see formula (I)), a strong siloxane bond (Si-O-Si) network structure is formed. The formation of this network structure is advantageous not only in terms of abrasion resistance but also in terms of improving hardness, water resistance, and other properties.

[0070] The water-repellent group should be added in such an amount that the water contact angle on the surface of the anti-fog film 3 is 70 degrees or more, preferably 80 degrees or more, and more preferably 90 degrees or more. The water contact angle should be determined by dropping 4 mg of water droplets onto the surface of the film and using that value. In particular, when using methyl or ethyl groups, which have somewhat weak water repellency, as the water-repellent group, it is preferable to incorporate an amount of the water-repellent group into the anti-fog film 3 such that the water contact angle falls within the above range. There is no particular upper limit to this water droplet contact angle, but for example, it should be 150 degrees or less, 120 degrees or less, or even 100 degrees or less. It is preferable to uniformly include the water-repellent group in the anti-fog film 3 so that the water contact angle falls within the above range across all areas of the surface of the anti-fog film 3.

[0071] Furthermore, the surface of the anti-fog film 3 can also be made water-repellent. This suppresses the penetration of alkaline components into the anti-fog film 3 and protects the surface of the glass plate 1 from alkaline components.

[0072] The anti-fogging film 3 preferably contains water-repellent groups in an amount of 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and 10 parts by mass or less, preferably 5 parts by mass or less, per 100 parts by mass of the water-absorbing resin.

[0073] (Inorganic oxides) The inorganic oxide is, for example, an oxide of at least one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce, and Sn, and includes at least an oxide of Si (silica). The organic-inorganic composite anti-fogging film preferably contains inorganic oxide in an amount of 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, even more preferably 0.2 parts by weight or more, particularly preferably 1 part by weight or more, most preferably 5 parts by weight or more, possibly 10 parts by weight or more, if necessary 20 parts by weight or more, also preferably 50 parts by weight or less, more preferably 45 parts by weight or less, even more preferably 40 parts by weight or less, particularly preferably 35 parts by weight or less, most preferably 33 parts by weight or less, and possibly 30 parts by weight or less, per 100 parts by weight of the water-absorbing resin. The inorganic oxide is a necessary component to ensure the strength of the organic-inorganic composite anti-fogging film, especially its abrasion resistance, but if its content is high, the anti-fogging properties of the organic-inorganic composite anti-fogging film will decrease.

[0074] (Inorganic oxide fine particles) The organic-inorganic composite anti-fogging film may further contain inorganic oxide fine particles as at least a portion of the inorganic oxide. The inorganic oxide constituting the inorganic oxide fine particles is, for example, an oxide of at least one element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce, and Sn, and is preferably silica fine particles. Silica fine particles can be introduced into the organic-inorganic composite anti-fogging film by adding colloidal silica, for example. Inorganic oxide fine particles have excellent ability to transmit stress applied to the organic-inorganic composite anti-fogging film to the article supporting the organic-inorganic composite anti-fogging film, and also have high hardness. Therefore, the addition of inorganic oxide fine particles is advantageous from the viewpoint of improving the wear resistance of the organic-inorganic composite anti-fogging film. In addition, when inorganic oxide fine particles are added to the organic-inorganic composite anti-fogging film, fine voids are formed in the areas where the fine particles are in contact with or close to the film, and water vapor is more easily taken into the film through these voids. For this reason, the addition of inorganic oxide fine particles may also have an advantageous effect on improving anti-fogging properties. Inorganic oxide fine particles can be supplied to an organic-inorganic composite anti-fogging film by adding pre-formed inorganic oxide fine particles to a coating solution for forming an organic-inorganic composite anti-fogging film.

[0075] If the average particle size of inorganic oxide fine particles is too large, the organic-inorganic composite anti-fogging film may become cloudy, and if it is too small, it will aggregate and become difficult to disperse uniformly. From this viewpoint, the average particle size of inorganic oxide fine particles is preferably 1 to 20 nm, more preferably 5 to 20 nm. Here, the average particle size of inorganic oxide fine particles is described in terms of primary particle state. Furthermore, the average particle size of inorganic oxide fine particles is determined by measuring the particle size of 50 arbitrarily selected fine particles by observation using a scanning electron microscope and adopting the average value. If the content of inorganic oxide fine particles is too high, the water absorption capacity of the entire organic-inorganic composite anti-fogging film will decrease, and the organic-inorganic composite anti-fogging film may become cloudy. The inorganic oxide fine particles should preferably be added in an amount of 0 to 50 parts by weight, more preferably 2 to 30 parts by weight, even more preferably 5 to 25 parts by weight, and particularly preferably 10 to 20 parts by weight, per 100 parts by weight of the water-absorbing resin.

[0076] (Hydrolyzable metal compounds that do not have water-repellent groups) The anti-fogging film may contain a metal oxide component derived from a hydrolyzable metal compound that does not have a water-repellent group (hydrolyzable compound without a water-repellent group). A preferred hydrolyzable metal compound without a water-repellent group is a hydrolyzable silicon compound that does not have a water-repellent group. A hydrolyzable silicon compound without a water-repellent group is, for example, at least one silicon compound selected from silicon alkoxides, chlorosilanes, acetoxysilanes, alkenyloxysilanes, and aminosilanes (provided that it does not have a water-repellent group), with silicon alkoxides without a water-repellent group being preferred. Isopropenoxysilane can be given as an example of an alkenyloxysilane.

[0077] Hydrolyzable silicon compounds that do not have a water-repellent group may be compounds shown in the following formula (III). SiY4(III) As described above, Y is a hydrolyzable functional group, preferably at least one selected from an alkoxy group, an acetoxy group, an alkenyloxy group, an amino group, and a halogen atom.

[0078] Hydrolyzable metal compounds that do not contain water-repellent groups undergo hydrolysis or partial hydrolysis, and at least a portion of them undergo polycondensation to supply a metal oxide component in which metal atoms and oxygen atoms are bonded. This component firmly bonds the metal oxide fine particles to the water-absorbing resin and can contribute to improving the abrasion resistance, hardness, water resistance, etc. of the anti-fogging film. The amount of metal oxide component derived from hydrolyzable metal compounds that do not have water-repellent groups is preferably in the range of 0 to 40 parts by mass, preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, particularly preferably 3 to 10 parts by mass, and possibly 4 to 12 parts by mass, per 100 parts by mass of water-absorbing resin.

[0079] A preferred example of a hydrolyzable silicon compound that does not have a water-repellent group is a tetraalkoxysilane, more specifically a tetraalkoxysilane having an alkoxy group with 1 to 4 carbon atoms. A tetraalkoxysilane is, for example, at least one selected from tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, and tetra-tert-butoxysilane.

[0080] If the content of metal oxide (silica) components derived from tetraalkoxysilane is excessive, the anti-fogging properties of the anti-fogging film may decrease. This is partly because the flexibility of the anti-fogging film decreases, limiting the swelling and contraction of the film due to moisture absorption and release. The metal oxide components derived from tetraalkoxysilane should be added in the range of 0 to 30 parts by mass, preferably 1 to 20 parts by mass, and more preferably 3 to 10 parts by mass, per 100 parts by mass of the water-absorbing resin.

[0081] Another preferred example of a hydrolyzable silicon compound that does not have a water-repellent group is a silane coupling agent. A silane coupling agent is a silicon compound having different reactive functional groups. Preferably, some of the reactive functional groups are hydrolyzable functional groups. A silane coupling agent is, for example, a silicon compound having an epoxy group and / or an amino group and a hydrolyzable functional group. Examples of preferred silane coupling agents include glycidyloxyalkyltrialkoxysilanes and aminoalkyltrialkoxysilanes. In these silane coupling agents, it is preferable that the alkylene group directly bonded to the silicon atom has 1 to 3 carbon atoms. Although glycidyloxyalkyl groups and aminoalkyl groups contain an alkylene group, they are not water-repellent overall because they contain a hydrophilic functional group (epoxy group, amino group).

[0082] Silane coupling agents firmly bond organic components such as water-absorbing resins with inorganic components such as metal oxide fine particles, contributing to improvements in the abrasion resistance, hardness, and water resistance of the anti-fogging film 3. However, if the content of metal oxide (silica) components derived from the silane coupling agent becomes excessive, the anti-fogging properties of the anti-fogging film 3 will decrease, and in some cases, the anti-fogging film 3 may become cloudy. The metal oxide components derived from the silane coupling agent should be added in an amount of 0 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2 parts by mass, per 100 parts by mass of water-absorbing resin.

[0083] (Crosslinked structure) The anti-fog film 3 may contain a crosslinked structure derived from a crosslinking agent, preferably at least one crosslinking agent selected from organoboron compounds, organotitanium compounds, and organozirconium compounds. The introduction of the crosslinked structure improves the abrasion resistance, scratch resistance, and water resistance of the anti-fog film 3. From another perspective, the introduction of the crosslinked structure facilitates the improvement of the durability of the anti-fog film 3 without reducing its anti-fog performance.

[0084] When a crosslinked structure derived from a crosslinking agent is introduced into an anti-fogging film 3 in which the metal oxide component is silica, the anti-fogging film may contain, along with silicon, metal atoms other than silicon, preferably boron, titanium, or zirconium.

[0085] The type of crosslinking agent is not particularly limited, as long as it can crosslink the absorbent resin used. Here, only organotitanium compounds are given as examples. Organotitanium compounds are, for example, at least one selected from titanium alkoxides, titanium chelates, and titanium acylates. Examples of titanium alkoxides include titanium tetraisopropoxide, titanium tetra-n-butoxide, and titanium tetraoctoxide. Examples of titanium chelates include titanium acetylacetonate, titanium acetate acetate, titanium octylene glycol, titanium triethanolamine, and titanium lactate. Titanium lactate may also be an ammonium salt (titanium lactate ammonium). Examples of titanium acylates include titanium stearate. Preferred organotitanium compounds are titanium chelates, particularly titanium lactate.

[0086] When the water-absorbent resin is polyvinyl acetal, the preferred crosslinking agent is an organotitanium compound, particularly titanium lactate.

[0087] (Other optional components) Other additives may be added to the anti-fogging film 3. Examples of additives include glycols such as glycerin and ethylene glycol, which have the function of improving anti-fogging properties. Additives may also include surfactants, leveling agents, UV absorbers, colorants, defoamers, preservatives, etc.

[0088] (base layer) The anti-fog film 3 can be laminated directly onto the glass plate 1, or a base layer can be formed on the glass plate 1, and the anti-fog film 3 can be laminated on top of that. By laminating the anti-fog film 3 onto the glass plate 1 via a base layer in this way, the anti-fog film 3 can be made less likely to peel off. For example, a silane coupling agent can be used for the base layer.

[0089] [film thickness] The thickness of the organic-inorganic composite anti-fog film can be adjusted as appropriate according to the required anti-fog properties and other factors. The thickness of the organic-inorganic composite anti-fog film is preferably 2 to 15 μm, more preferably 2 to 12 μm, and even more preferably 3 to 10 μm. If the thickness of the anti-fog film 3 is 2 μm or more, a sufficient anti-fog effect can be obtained. On the other hand, if the anti-fog film 3 is too thick, the reflected image may be distorted due to uneven film thickness. Also, since the anti-fog film 3 is formed from a resin material as described above and has a birefringence, if it is too thick, the image may become blurred.

[0090] Furthermore, the thickness of the anti-fog film 3 can also be determined from a different perspective than those described above. Since the anti-fog film 3 is in close contact with the glass plate 1, for example, a thickness of 5 μm or more of the anti-fog film 3 is preferable because it can prevent fragments from scattering when the glass plate 1 breaks. From this perspective, a thickness of 10 μm or more of the anti-fog film 3 is even more preferable. In addition, it is preferable that the difference in optical film thickness of the anti-fog film 3 is 150 nm or more. The difference in optical film thickness is calculated by multiplying the difference between the minimum and maximum film thickness when observing the anti-fog film 3 by the refractive index of the anti-fog film.

[0091] <1-5. Relationship between anti-fog coating and interference fringes> The inventors have made the following findings regarding interference fringes that may occur in the glass body 10 when the anti-fogging film 3 is formed. (1) When interference fringes occur, for example, in the case of a semi-transparent reflective film 2 with a visible light reflectance of 30% or more, the interference fringes become clearer due to its high reflectance.

[0092] (2) When an anti-fogging film 3 is formed on a semi-transparent reflective film 2, interference fringes become more visible when the difference in optical film thickness of the anti-fogging film 3 is 150 nm or more, because the phase shift due to the difference in optical film thickness is large.

[0093] (3) By making the thickness of the anti-fog film 3 10 μm or more, the regularity of the wavefront of the visible light incident on the anti-fog film 3 becomes unclear or disappears when it reaches the interface of the anti-fog film 3 on the opposite side of the incident surface, thereby making the interference fringes caused by variations in the thickness of the anti-fog film 3 unclear or disappear. This is for the following reasons.

[0094] First, the light incident on the glass body 10 is generally incoherent light, such as natural light or lamp light. However, incoherent light does not have a uniform wavefront. When the optical path length is short, the wavefront of the light at the incident surface shows regularity, and interference fringes are produced. On the other hand, when the optical path length is long, the regularity of the wavefront observed at the incident surface becomes difficult to discern, and when it exceeds the coherence distance, the regularity of the wavefront observed at the incident surface disappears. Therefore, when the optical path length is long, the regularity of the wavefront of the reflected light becomes difficult to discern, and the interference fringes with the light reflected at the incident surface become unclear. Furthermore, when the optical path length exceeds the coherence distance, the interference fringes disappear.

[0095] <1-6. Method for forming anti-fogging film> Next, the method for forming the anti-fogging film 3 will be described. The method for forming the anti-fogging film 3 is not particularly limited, but for example, the organic-inorganic composite anti-fogging film 3 described above can be formed by applying a coating solution for forming the organic-inorganic composite anti-fogging film onto a glass plate 1 such as a transparent substrate, and then drying the applied coating solution. Known materials and methods can be used for the solvent used to prepare the coating solution and the method for applying the coating solution. At this time, it is preferable to maintain the relative humidity of the atmosphere at less than 40%, and more preferably at 30% or less. Maintaining a low relative humidity prevents the organic-inorganic composite anti-fogging film from excessively absorbing moisture from the atmosphere. If a large amount of moisture is absorbed from the atmosphere, the water that enters the matrix of the organic-inorganic composite anti-fogging film and remains there may reduce the strength of the film.

[0096] The drying process for the coating solution preferably includes an air-drying process and a heat-drying process. The air-drying process is preferably carried out by exposing the coating solution to an atmosphere where the relative humidity is maintained at less than 40%, and even less than 30%. The air-drying process can be carried out as a non-heating process, in other words, at room temperature. If the coating solution contains a hydrolyzable silicon compound, in the heat-drying process, a dehydration reaction involving silanol groups contained in the hydrolysates of the silicon compound and hydroxyl groups present on the article proceeds, and a matrix structure (a network of Si-O bonds) consisting of silicon atoms and oxygen atoms develops. The air-drying process can be carried out for about 10 minutes, for example.

[0097] To avoid the decomposition of organic materials such as water-absorbing resins, the temperature applied in the heating and drying process should not be excessively high. An appropriate heating temperature in this case is 300°C or lower, for example, 100-200°C. Specifically, three steps can be performed. For example, the material is baked at approximately 120°C for about 5 minutes, dried at approximately 80°C and 90% humidity for about 2 hours, and then baked again at approximately 120°C for about 30 minutes. In this way, the formation of the anti-fogging film 3 is completed.

[0098] <1-7. Haze rate of the vitreous body> Although the glass body 10 is a half-mirror, it can be used as a cover for an article. Therefore, it is preferable that the haze rate of the glass body 10 is low so that the article can be seen through the glass body 10. For example, the haze rate of the glass body 10 is preferably 2.0% or less, and more preferably 1.5% or less.

[0099] For measuring the haze rate, for example, an integrating sphere type light transmittance meter (HGM-2DP, manufactured by Suga Test Instruments Co., Ltd., using a C light source, with light incident from the film surface side) can be used. Measurements can be taken from either the semi-transparent reflective film 2 or the anti-fogging film 3.

[0100] <2. Features> The glass body 10 according to this embodiment can achieve the following effects. (1) The glass body 10 according to this embodiment has a semi-transparent reflective film 2 with adjusted visible light reflectance and visible light transmittance, and can therefore be used as a half mirror. In addition, because it has an anti-fogging film 3, fogging of the glass plate 1 can be suppressed.

[0101] (2) In this embodiment, a semi-transparent reflective film is laminated on the first surface 11 of the glass plate 1 and an anti-fogging film 3 is laminated on the second surface 12, which has the following advantages.

[0102] (2-1) For example, if an anti-fogging film 3 is laminated on a semi-transparent reflective film 2, interference fringes may occur depending on the light source. However, if the semi-transparent reflective film 2 and the anti-fogging film 3 are laminated on each surface 11, 12 of the glass plate 1, the occurrence of interference fringes can be suppressed.

[0103] (2-2) When the glass plate 1 is float glass, the precipitation of alkaline components contained in the glass plate 1 is suppressed on the bottom surface, which has a high tin oxide content. Therefore, when the anti-fog film 3 is laminated on the bottom surface of the glass plate 1, deterioration such as whitening of the anti-fog film 3 due to alkaline components can be suppressed. In particular, if the anti-fog film 3 is an organic-inorganic composite anti-fog film, it is prone to deterioration by alkaline components. For this reason, it is advantageous to laminate the anti-fog film 3 on the bottom surface of the glass plate 1. On the other hand, the top surface of the glass plate 1 has a low tin oxide content, so alkaline components are more likely to precipitate on it compared to the bottom surface. However, since the semi-transparent reflective film 2 is formed of inorganic metal oxides, it is less affected by alkaline components and deterioration is suppressed.

[0104] (2-3) Laminating the anti-fog film 3 onto the glass plate 1 results in better adhesion than laminating the anti-fog film 3 onto the semi-transparent reflective film 2. This is because the glass plate 1 and the anti-fog film 3 adhere to each other through silanol bonds.

[0105] (3) As described above, if the surface roughness Ra of the semi-transparent reflective film 2 or the glass plate 1 is small, the haze ratio can be reduced. However, if the surface roughness Ra is small, water droplets are more likely to adhere during condensation, which may cause fogging. Therefore, in this embodiment, an anti-fog film 3 is laminated on the second surface 12 of the glass plate 1 to suppress fogging on the second surface 12 of the glass plate 1, which is prone to water droplet adhesion. Note that if the surface roughness Ra is large, a water film is more easily formed during condensation, which increases the surface area of ​​the water, making it easier to evaporate and less likely to fog up.

[0106] The orientation of the glass body 10 is not particularly limited, but it is preferable to orient the anti-fog film 3 toward the side where fogging is more likely to occur, for example, the side with a higher temperature.

[0107] <3. Variant> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. The following modifications can be combined as appropriate.

[0108] <3-1> In the above embodiment, the anti-fog film 3 was laminated on the second surface 12 of the glass plate 1, but for example, as shown in Figure 4, the anti-fog film 3 can also be laminated on the semi-transparent reflective film 2. This provides the following effects. (1) If the thermal conductivity of the semi-transparent reflective film 2 is greater than that of the glass plate 1, then, for example, if the glass plate 1 side of the glass body 10 is cooled, heat from the semi-transparent reflective film 2 side will be more easily transferred to the semi-transparent reflective film 2, making fogging more likely. Therefore, by laminating an anti-fogging film 3 on the semi-transparent reflective film 2, such fogging can be suppressed.

[0109] (2) For example, if the outermost layer of the semi-transparent reflective film 2 is SiO2, then because SiO2 has low alkali resistance, if the semi-transparent reflective film is cleaned with an alkaline detergent, the SiO2 may deteriorate due to the alkaline components. Therefore, covering the SiO2 with the anti-fog film 3 can protect the SiO2 from alkaline components. In particular, if the surface of the anti-fog film 3 is made water-repellent, the penetration of alkaline components into the anti-fog film 3 can be suppressed, and the SiO2 can be further protected.

[0110] (3) Since the anti-fog film 3 does not come into direct contact with the glass plate 1, alkaline components precipitated from the glass plate 1 come into contact with the anti-fog film 3, preventing the anti-fog film 3 from deteriorating, such as whitening.

[0111] Furthermore, when the anti-fog film 3 is laminated on the semi-transparent reflective film 2, interference fringes may easily occur as described above. In this case, it is preferable to reduce the difference in refractive index between the anti-fog film 3 and the semi-transparent reflective film 2. Specifically, it is preferable that the difference in refractive index be 0.1 or less. Reducing the difference in refractive index suppresses reflection at the interface between the anti-fog film 3 and the semi-transparent reflective film 2, thereby suppressing interference. Also, a smaller difference in refractive index reduces the amplitude of light, making interference fringes less visible. Moreover, if the refractive index of the anti-fog film 3 is 1.6 or less, interference fringes can be further suppressed.

[0112] <3-2> The anti-fog film 3 can also be laminated on both the semi-transparent reflective film 2 and the second surface 12 of the glass plate 1.

[0113] <3-3> In the above embodiment, the anti-fog film 3 was directly laminated onto the second surface 12 of the glass plate 1, but an anti-fog sheet can also be attached. The anti-fog sheet comprises a sheet-shaped transparent film substrate, the anti-fog layer laminated on one surface of the film substrate, and a transparent adhesive layer laminated on the other surface of the film substrate. The anti-fog sheet can then be fixed to the glass plate 1 by fixing the adhesive layer to the second surface 12 of the glass plate 1.

[0114] The film substrate can be formed from a transparent resin sheet, such as polyethylene or polyethylene terephthalate. The thickness of the film substrate can be, for example, 10 to 100 μm, and more preferably 75 to 100 μm. When the thickness of the film substrate is 10 μm or more, the generation of interference fringes between the semi-transparent reflective film 2 and the anti-fogging film 3 can be suppressed. The adhesive layer can be formed from, for example, an acrylic or silicone adhesive. Such an anti-fogging sheet can also be attached to the semi-transparent reflective film 2. In this case, since the film substrate has sufficient thickness, interference fringes can be suppressed.

[0115] <3-3> A light-shielding film can also be formed on the anti-fog film 3. For example, as shown in Figures 5 and 6, a light-shielding film 4 can be formed along the periphery of the glass body 10, but the shape of the light-shielding film 4 is not particularly limited and can be formed appropriately in the area where light shielding is to be performed. The material constituting the light-shielding film 4 is not particularly limited as long as it has light-shielding properties, but for example, dark-colored inks such as black, brown, gray, and dark blue can be laminated on the anti-fog film 3 by printing. As a specific material, the light-shielding film 4 can be made of resins such as urethane resin, epoxy resin, acrylic resin, or polyethylene resin mixed with a pigment. The thickness of the light-shielding film 3 is not particularly limited, but for example, it can be 30 to 100 μm. In addition, a dark-colored film can be attached to the anti-fog film 3 as a light-shielding film. Note that light shielding means, for example, that the visible light transmittance is 20% or less.

[0116] However, in order to suppress the visibility of the inner edge of the light-shielding film 4, that is, the boundary between the light-shielding film 4 and the area where the light-shielding film 4 is not laminated, the light-shielding film 4 can be made warm in color, etc., by adjusting the pigment, rather than being a dark color. For example, the color of the light-shielding film 4 can be set to a chromaticity a* of -10 to 50, a chromaticity b* of -10 to 50, and a chromaticity L* of 10 to 100 in the L*, a*, b* color system (CIE standard). A chromaticity a* is preferably 0 to 30, and more preferably 5 to 20. A chromaticity b* is preferably 0 to 30, and more preferably 5 to 20. Also, a chromaticity L* is preferably 10 to 50, and more preferably 10 to 30. This makes it possible to suppress the visibility of the boundary of the light-shielding film 4 when viewed from the second area 62 side.

[0117] In the above explanation, an example was shown in which the light-shielding film 4 was formed on the anti-fog film 3, but it can also be formed on the semi-transparent reflective film 2 in the same manner. Alternatively, the light-shielding film 4 can be formed on both the anti-fog film 3 and the semi-transparent reflective film 2.

[0118] <3-4> The shape of the glass plate 1 is not particularly limited, and various shapes are possible. Furthermore, the semi-transparent reflective film 2 and the anti-fogging film 3 do not need to be formed over the entire surface of the glass plate 1, but only on the necessary area of ​​the glass plate 1. [Explanation of Symbols]

[0119] 1 glass plate 2 Transflective film 3. Anti-fog coating 4. Light-shielding film

Claims

1. A glass plate having a first surface and a second surface opposite to the first surface, A semi-transparent reflective film disposed on the first surface of the glass plate, An anti-fogging means arranged on the second surface of the glass plate, Equipped with, The glass plate is float glass, The concentration of tin oxide on the first surface is lower than the concentration of tin oxide on the second surface. The anti-fogging means comprises an anti-fogging film, the anti-fogging film is provided on the second surface of the glass plate, The semi-transparent reflective film is formed by stacking multiple layers, and at least one of the multiple layers is made of an inorganic metal oxide. The anti-fogging film comprises at least a water-absorbing resin and a metal oxide component derived from a hydrolyzable metal compound having a water-repellent group. Half-mirror.

2. A glass plate having a first surface and a second surface opposite to the first surface, A semi-transparent reflective film disposed on the first surface of the glass plate, An anti-fogging means arranged on the second surface of the glass plate, Equipped with, The glass plate is float glass, The concentration of tin oxide on the first surface is lower than the concentration of tin oxide on the second surface. The anti-fogging means comprises an anti-fogging film, the anti-fogging film is provided on the second surface of the glass plate, The semi-transparent reflective film is formed by stacking multiple layers, and at least one of the multiple layers is made of an inorganic metal oxide. The anti-fogging film comprises at least metal oxide fine particles, a water-absorbing resin, and a metal oxide component derived from a hydrolyzable metal compound that does not have a water-repellent group. Half-mirror.

3. The half mirror according to claim 1 or 2, wherein the surface roughness Ra of the semi-transparent reflective film is 15 nm or less.

4. The half mirror according to claim 1, wherein the anti-fogging film is provided on the semi-transparent reflective film.

5. The half mirror according to claim 4, wherein the difference in refractive index between the anti-fog film and the outermost layer of the semi-transparent reflective film adjacent to the anti-fog film is 0.1 or less.

6. The half mirror according to claim 5, wherein the refractive index of the anti-fogging film is 1.6 or less.

7. The difference in optical film thickness of the aforementioned anti-fogging film is 150 nm or more. The half mirror according to any one of claims 4 to 6, wherein the thickness of the anti-fogging film is 10 μm or more.

8. The aforementioned anti-fogging means is The aforementioned anti-fogging film, A film substrate having a thickness of 10 μm or more that supports the anti-fogging film, The film substrate is provided with an adhesive layer located on the side opposite to the anti-fogging film, for fixing the film substrate to the semi-transparent reflective film. A half mirror according to any one of claims 4 to 7, comprising:

9. A half-mirror according to any one of claims 1 to 8, wherein the haze rate is 2% or less.

10. The half mirror according to any one of claims 1 to 9, wherein the thickness of the anti-fogging film is 5 μm or more.

11. A half mirror according to any one of claims 1 to 10, wherein the visible light transmittance is 20% or more and 70% or less.

12. The reflected color tone from the semi-transparent reflective film side is such that, in the L*a*b* color system, the value of a* is between -15 and 15. The half mirror according to any one of claims 1 to 11, wherein the reflected color tone from the semi-transparent reflective film side is such that, in the L*a*b* color system, the value of b* is between -15 and 15.

13. The half mirror according to any one of claims 1 to 12, wherein the thermal conductivity of the semi-transparent reflective film is greater than that of the glass plate.

14. The half-mirror according to any one of claims 1 to 13, wherein at least one of the plurality of layers is a metallic reflective layer formed of a metal or a metalloid.

15. The half mirror according to claim 14, wherein the metal reflective layer is mainly composed of at least one of Si, Ag, Al, Cr, Ti, and Mo.

16. The half-mirror according to claim 14 or 15, wherein the outermost layer of the semi-transparent reflective film has a refractive index of 1.5 or less in the visible light region.

17. The main component of the outermost layer is SiO 2 The half mirror according to claim 16.

18. The half mirror according to claim 17, wherein the anti-fogging film is provided on the semi-transparent reflective film.

19. The half mirror according to any one of claims 1 to 18, wherein the surface of the anti-fogging film is treated with a water-repellent coating.

20. The half mirror according to claim 19, wherein the water contact angle of the surface of the anti-fog film is 70° or more.

21. The anti-fogging film is disposed on the semi-transparent reflective film and on the second surface of the glass plate, as described in any one of claims 1 to 20.

22. The half mirror according to any one of claims 1 to 21, further comprising a light-shielding film formed on at least one of the anti-fog film and the semi-transparent reflective film.

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