Sealing material and multilayer glass panel using the same

Abstract

The present invention provides a sealing material and a multilayer glass panel using the same. A multilayer glass panel with high reliability and a sealing material for achieving the same are provided. A sealing material, comprising: a lead-free low-melting glass particle containing vanadium oxide and tellurium oxide, a low-thermal expansion filler particle, and a glass bead as solid components, the volume content of the glass bead in the solid components being 10% or more and 35% or less, the volume content of the lead-free low-melting glass particle in the solid components being greater than the volume content of the low-thermal expansion filler in the solid components.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201880076212.4, filed on November 1, 2018, entitled “Sealing Material and Multilayer Glass Panel Using the Same”. TECHNICAL FIELD

[0002] The present application relates to a sealing material and a multilayer glass panel using the same. BACKGROUND

[0003] In recent years, window glasses that have significantly higher thermal insulation than conventional multilayer glass windows are required. In order to achieve this, high thermal insulation resulting from high vacuumization of the inside of the multilayer glass window is required. In addition, in order to be widely popularized worldwide, development needs to be conducted while sufficiently considering the manufacturing cost of the multilayer glass window and the like.

[0004] If high vacuumization of the inside of the panel of the multilayer glass window is to be achieved, the number of spacers for securing the internal space of the panel needs to be increased. The spacers are generally made of a cylindrical metal. However, the thermal conductivity of the metal is high, and thus, when the number of spacers is large, a contradictory problem that even if the degree of vacuum is increased, the thermal insulation decreases can occur.

[0005] It is also considered to use a ceramic or glass having lower thermal conductivity than the metal as the spacer. However, the ceramic and the glass are harder than the metal. Thus, it is possible that the panel glass is scratched and the vacuum thermal insulation multilayer glass panel is broken.

[0006] The thermal conductivity of the resin is low, and thus, it is effective to apply the resin to the spacer instead of the metal, the ceramic, and the glass. However, on the other hand, the heat resistance of the resin is lower than that of the metal, the ceramic, and the glass, and thus, hermetic sealing needs to be performed at a low temperature below the heat resistance temperature thereof. Thus, in the case where the resin is used for the spacer, it is difficult to apply the conventional lead-based low-melting-point glass and bismuth-based low-melting-point glass, which have a high sealing temperature.

[0007] Further, in order to prevent breakage, safety, crime prevention, and the like caused by high vacuumization, for the panel glass, a strengthened glass that is not easily broken and on which a forced air cooling strengthening treatment or the like is applied is required. The strengthened glass achieves high strength by forming a compressive strengthened layer on the surface. However, the strengthened layer of the conventional lead-based low-melting-point glass and bismuth-based low-melting-point glass is slowly reduced at a heating temperature of about 320°C or higher and disappears at about 400°C or higher. Thus, in the case of the conventional lead-based low-melting-point glass and bismuth-based low-melting-point glass, which have a sealing temperature of 400°C or higher, it is difficult to apply the strengthened glass to the panel glass.

[0008] As described above, in order to achieve high vacuumization of the inside of the panel and high thermal insulation of the panel in the vacuum thermal insulation multilayer glass panel, low-temperature sealing becomes very important.

[0009] In Patent Literature 1, a lead-free low-melting glass composition containing, when the components are expressed in oxides, 10 to 60 mass% of Ag20, 5 to 65 mass% of V205, 15 to 50 mass% of Te02, the total content of Ag20, V205, and Te02 being 75 mass% or more and less than 100 mass%, and the remainder containing one or more of P205, BaO, K20, W03, Fe203, Mn02, Sb203, and ZnO in more than 0 mass% and 25 mass% or less is disclosed. The softening point of the Ag20-V205-Te02-based lead-free low-melting glass is in the temperature range of 268 to 320°C, and the glass softens and flows at a significantly lower temperature than conventional lead-based or bismuth-based low-melting glasses.

[0010] In Patent Literature 2, a glass adhesive material containing a vanadium-based (V205-P205-based) low-melting glass (vanadium-phosphoric acid glass) and filler particles, which can be applied as an adhesive material for a glass panel of a flat panel display device and which does not lose transparency in a sealing process and can achieve high bonding strength, is disclosed. The glass adhesive material further contains 0.1 to 1.0% by volume of glass beads. Among them, the glass beads function as a skeletal material for attaching two panel glasses at equal intervals.

[0011] Prior Art Documents

[0012] Patent Literature

[0013] Patent Literature 1: Japanese Patent Application Publication No. 2013-32255

[0014] Patent Literature 2: Japanese Patent Application Publication No. 2007-320822 SUMMARY

[0015] PROBLEMS TO BE SOLVED BY THE INVENTION

[0016] The glass composition disclosed in Patent Literature 1 can perform airtight sealing at a low temperature of 320°C or lower. However, along with the lowering of the sealing temperature, there is a tendency that the mechanical strength of the sealed portion decreases. Therefore, there is room for improvement in the reliability of the sealed portion.

[0017] The vanadium-phosphoric acid glass disclosed in Patent Literature 2 has a softening point of about 400°C and a flow point of about 450 to 500°C, and thus research on the improvement of the mechanical strength of the sealed portion in association with the lowering of the sealing temperature is insufficient.

[0018] An object of the present application is to provide a multilayer glass panel with high reliability and a sealing material for achieving the same.

[0019] MEANS FOR SOLVING THE PROBLEMS

[0020] The sealing material of the present application contains: a lead-free low-melting glass particle containing vanadium oxide and tellurium oxide, a low-thermal expansion filler particle, and a glass bead as solid components, the volume content of the glass bead in the solid components being 10% or more and 35% or less, and the volume content of the lead-free low-melting glass particle in the solid components being greater than the volume content of the low-thermal expansion filler in the solid components.

[0021] Effects of Invention

[0022] According to the present application, a multilayer glass panel with high reliability and a sealing material for realizing the same can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1A A schematic perspective view of a representative vacuum-insulated multilayer glass panel.

[0024] Figure 1B A cross-sectional view of a vacuum-insulated multilayer glass panel and an enlarged cross-sectional view of a sealing portion thereof. Figure 1A

[0025] Figure 2 An enlarged cross-sectional view of a sealing portion of a vacuum-insulated multilayer glass panel according to an embodiment.

[0026] Figure 3A A schematic perspective view of a sealing material paste application process as part of a manufacturing method of a vacuum-insulated multilayer glass panel according to an embodiment.

[0027] Figure 3B An enlarged cross-sectional view of a peripheral portion of a vacuum-insulated multilayer glass panel. Figure 3A

[0028] Figure 4A A schematic perspective view of a heat radiation reflection film and spacer formation process as part of a manufacturing method of a vacuum-insulated multilayer glass panel according to an embodiment.

[0029] Figure 4B A schematic cross-sectional view of Figure 4A

[0030] A schematic cross-sectional view of a state in which two glass substrates are laminated as part of a manufacturing method of a vacuum-insulated multilayer glass panel according to an embodiment. Figure 5A

[0031] A schematic cross-sectional view of a state in which two glass substrates are fixed as part of a manufacturing method of a vacuum-insulated multilayer glass panel according to an embodiment. Figure 5B

[0032] Figure 6A ​​​A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0033] Figure 6B A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure. Figure 6A

[0034] Figure 7A A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0035] Figure 7B A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure. Figure 7A

[0036] A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure. Figure 8A

[0037] Figure 8B A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0038] Figure 9 A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0039] Figure 10A A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0040] Figure 10B A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure. Figure 10A

[0041] A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure. Figure 11A Figure 10B A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0042] Figure 11B Figure 11A A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0043] Figure 12 A schematic cross-sectional view showing a part of the manufacturing method of the vacuum heat-insulating multilayer glass panel according to an embodiment, which is a part of a process of reducing the internal space of the vacuum multilayer glass panel in pressure.

[0044] Figure 13 ​​​​A graph showing the relationship between the improvement rate of the bonding strength of the bonded body simulating the sealing portion of the vacuum heat-insulation multilayer glass panel and the volume content of the spherical glass beads in the solid component of the sealing material paste.

[0045] Figure 14 A graph showing the relationship between the improvement rate of the bonding strength of the bonded body simulating the sealing portion of the vacuum heat-insulation multilayer glass panel and the average particle diameter (D 50 ) of the spherical glass beads in the solid component of the sealing material paste.

[0046] Figure 15 A schematic cross-sectional view showing the outline of the reliability test device for the vacuum heat-insulation multilayer glass panel. DETAILED DESCRIPTION

[0047] Hereinafter, the embodiments of the present application will be described using the drawings. However, the present application is not limited to the embodiments listed here, and appropriate combinations, modifications can be made within the scope of the gist.

[0048] (Vacuum heat-insulation multilayer glass panel)

[0049] A vacuum heat-insulation multilayer glass panel (also simply referred to as "multilayer glass panel") applied to a window glass for a building or the like has an internal space between two glass substrates via a plurality of spacers. The internal space is in a vacuum state, and further, in order to maintain the vacuum state for a long time, the peripheral edge portions of the two glass substrates are hermetically sealed. For the hermetic sealing of the peripheral edge portions, a sealing material containing a low-melting glass and low-thermal expansion filler particles is applied, and the hermetic sealing portion becomes a state in which the low-thermal expansion filler is dispersed in the low-melting glass. In addition, in the vacuum heat-insulation multilayer glass panel, the distance between the two glass substrates (i.e., the height of the spacer, the thickness of the hermetic sealing portion) is generally in the range of 100 to 300 μm.

[0050] Figure 1A A schematic perspective view showing a representative vacuum heat-insulation multilayer glass panel.

[0051] Figure 1B A cross-sectional view corresponding to Figure 1A , showing the hermetic sealing portion thereof in enlargement.

[0052] In Figure 1A , the vacuum heat-insulation multilayer glass panel has a first glass substrate 1 and a second glass substrate 2, and a spacer 3 and a sealing portion 4 interposed therebetween. The sealing portion 4 is provided at the peripheral edge portions of the first glass substrate 1 and the second glass substrate 2.

[0053] In addition, as Figure 1BAs shown, an internal space 5 is formed by a region surrounded by the first glass substrate 1, the second glass substrate 2, and the sealing portion 4. The inner surface of the second glass substrate 2 is provided with a heat radiation reflection film 6. A plurality of spacers 3 are arranged to support the first glass substrate 1 and the second glass substrate 2 in such a manner that the distance between the first glass substrate 1 and the second glass substrate 2 becomes a prescribed value. In general, it is desirable to make this distance constant.

[0054] In the vacuum heat-insulating multi-layer glass panel, for the first glass substrate 1 and the second glass substrate 2, a soda-lime glass substrate having a coefficient of thermal expansion in the range of (80 to 90) x 10 -7 / °C is generally used.

[0055] As shown in an enlarged view of Figure 1B , the sealing portion 4 contains a low-melting glass 7 and low-thermal-expansion filler particles 8. The low-thermal-expansion filler particles 8 are dispersed in the low-melting glass 7. With the sealing portion 4, the vacuum state of the internal space 5 is achieved and maintained for a long period of time. The low-thermal-expansion filler particles 8 are mixed in order to adapt the coefficient of thermal expansion of the sealing portion 4 to the coefficients of thermal expansion of the first glass substrate 1 and the second glass substrate 2.

[0056] The heat radiation reflection film 6 is useful in the case where the vacuum heat-insulating multi-layer glass panel is applied to a building window glass, and is generally used.

[0057] In such a vacuum heat-insulating multi-layer glass panel, the sealing temperature is roughly determined by the softening flow characteristics brought about by the heating temperature of the low-melting glass 7 used in the sealing portion 4. That is, the lower the softening point of the low-melting glass 7 used, the lower the sealing temperature can be made. However, on the other hand, the lower the softening point of the low-melting glass 7 used, the more the mechanical strength tends to decrease. In addition, in this case, the coefficient of thermal expansion tends to increase. In order to cope with this, it is necessary to increase the volume content of the low-thermal-expansion filler particles 8 contained in the sealing portion 4.

[0058] Figure 2 A cross section of the sealing portion of a representative vacuum heat-insulating multi-layer glass panel to which an embodiment relates is shown on an enlarged scale.

[0059] Figure 2 The point of difference from the enlarged view of Figure 1B is that spherical glass beads 9 are also dispersed in the low-melting glass 7.

[0060] The low-melting glass 7 (lead-free low-melting glass) contains vanadium oxide (V2O5) and tellurium oxide (TeO2). With this composition, it is possible to make the sealing temperature less than 400°C.

[0061] The volume content of the glass beads 9 is 10% or more and 35% or less. The volume content of the low-melting glass 7 is greater than the volume content of the low-thermal-expansion filler particles 8.

[0062] By setting the volume content ratio of the glass beads 9 as described above, it is possible to prevent the mechanical strength from being impaired by aggregation in the sealing portion 4, and to improve the mechanical strength. Thus, it is possible to ensure the reliability of the vacuum multilayer glass panel. When the volume content ratio of the glass beads 9 is less than 10%, the improvement in the mechanical strength is hardly observed, on the other hand, when it exceeds 35%, the sealing portion 4 is easily peeled off from the interface of the first glass substrate 1 and the second glass substrate 2. Note that the volume content ratio of the glass beads 9 is more preferably 20% or more and 30% or less.

[0063] Further, in the case where the low-melting-point glass 7 contains silver oxide (Ag20), it is possible to make the sealing temperature less than 320°C. Thus, the spacer 3 can use a resin having low thermal conductivity. Further, it is possible to apply a strengthened glass subjected to air-cooling strengthening treatment or chemical strengthening treatment to the first glass substrate 1 and the second glass substrate 2. In addition, by lowering the sealing temperature, it is possible to improve the mass productivity of the vacuum multilayer glass panel, and to reduce the investment in mass production equipment, which contributes to the reduction in manufacturing cost.

[0064] As for the size of the glass beads 9, it is necessary that the maximum diameter thereof is equal to or less than the interval between the first glass substrate 1 and the second glass substrate 2. In addition, it is preferable that the average diameter (D 50 ) thereof is equal to or more than half of the interval. Here, the average diameter (D 50 ) is the median diameter, also called "average particle diameter". The average particle diameter (D 50 ) of the glass beads 9 can be measured, for example, by using a laser diffraction / scattering type particle size distribution measuring device after fractionation with a sieve.

[0065] The glass beads 9 are preferably the same or similar glass system as the first glass substrate 1 and the second glass substrate 2. This is because the thermal expansion characteristics are the same or close, and thus it is possible to stably improve the mechanical strength of the sealing portion.

[0066] Specifically, it is preferable to use glass beads of soda-lime glass (Si02-Na20-CaO-based glass), borosilicate glass (Si02-B203-Na20-based glass), quartz glass (Si02), or the like.

[0067] Note that in the present specification, glass beads are defined as glass in a substantially spherical shape. Also, in the vacuum heat-insulating multilayer glass panel, the low-thermal expansion filler particles 8 are introduced in order to make the thermal expansion of the sealing portion 4 fit the thermal expansion of the first glass substrate 1 and the second glass substrate 2, but when the volume content of the low-melting glass 7 is equal to or greater than the volume content of the low-thermal expansion filler particles 8, the softening flowability of the low-melting glass 7 at the time of heat sealing decreases, and it becomes difficult to perform airtight sealing. Therefore, it is necessary to make the volume content of the low-melting glass 7 greater than the volume content of the low-thermal expansion filler particles 8. More preferably, it is effective to set the volume content of the low-melting glass 7 to 35% or greater. Also, the volume content of the low-melting glass 7 is preferably 72% or less.

[0068] In the case where the low-melting glass 7 further contains any one or more of an oxide (WO3), barium oxide (BaO), potassium oxide (K2O), and phosphorus oxide (P2O5) as a glass component, it is possible to make vitrification at the time of glass production easy. With such a composition, it is possible to reduce the tendency of crystallization of the produced low-melting glass 7. When the tendency of crystallization of the low-melting glass 7 is great, there is a problem that crystallization occurs at the time of heat sealing, good softening flow characteristics are not obtained, and the sealing portion 4 does not have high airtightness.

[0069] Also, it is effective to further contain any one or more of aluminum oxide (Al2O3), iron oxide (Fe2O3), yttrium oxide (Y2O3), and lanthanum oxide (La2O3) as a glass component. These components are effective in preventing or significantly suppressing crystallization even in small amounts. Thereby, a sealing portion 4 having high airtightness is obtained.

[0070] The low-thermal expansion filler particles 8 can use, for example, particles formed of zirconium tungsten phosphate (Zr2(WO4)(PO4)2), quartz glass, β-eucryptite, or cordierite.

[0071] Among these, zirconium tungsten phosphate is effective. Zirconium tungsten phosphate has a large negative thermal expansion, and the coefficient of thermal expansion is -40 x 10 -7 / °C. Furthermore, the low-thermal expansion filler particles 8 have good wettability and adhesion with the low-melting glass 7 described above, and therefore, a large effect of low-thermal expansion and easiness in making the thermal expansion of the sealing portion 4 fit the thermal expansion of the glass substrate are obtained. The average particle diameter (D 50 ) of the low-thermal expansion filler is preferably 3 μm or greater and 20 μm or less. By being 3 μm or greater and 20 μm or less, it is possible to suppress the generation of cracks at the interface, and it is possible to obtain the effect of adjustment of the coefficient of thermal expansion. Note that the average particle diameter (D 50 ) of the low-thermal expansion filler can be measured using a laser diffraction / scattering type particle size distribution measuring device.

[0072] In particular, when a lead-free low-melting glass containing vanadium oxide (V2O5), tellurium oxide (TeO2), and silver oxide (Ag2O) is used for the sealing portion, the sealing temperature can be lowered, and thus the spacer 3 described above can use a resin having low thermal conductivity. As specific resins, polyimide resin, polyamide resin, fluorine resin, epoxy resin, phenoxy resin, and silicone resin can be given.

[0073] Generally, a resin is softer than metal, ceramic, and glass, and thus, when used for the spacer 3, the first glass substrate 1 and the second glass substrate 2 are not scratched and broken. In addition, when hardness is required for the spacer 3, glass particles or ceramic particles can be dispersed in the resin as a filler material.

[0074] The vacuum heat-insulating multilayer glass panel according to the present embodiment is excellent in heat-insulating properties, mass productivity, and reliability, and thus is effective particularly for use in architectural window glass. Furthermore, it is easy to spread widely to the world's residential, architectural, and other fields. Thus, it is possible to reduce CO2 emissions by reducing energy usage, and contribute to countermeasures against global warming. In addition, the vacuum heat-insulating multilayer glass panel can be applied not only to architectural window glass but also to, for example, vehicle window glass, commercial refrigerators, doors of freezing chambers, and other places and products requiring heat-insulating properties.

[0075] (Sealing material paste)

[0076] Figure 2 The sealing portion 4 of the vacuum heat-insulating multilayer glass panel illustrated is generally formed using a sealing material paste. The sealing material paste contains particles of a low-melting glass 7 containing vanadium oxide (V2O5) and tellurium oxide (TeO2), low-thermal expansion filler particles 8, glass beads 9, a binder resin, and a solvent.

[0077] Note that, in the present specification, of the constituent elements of these sealing material pastes, the solid components are described as the three of the low-melting glass 7, the low-thermal expansion filler particles 8, and the glass beads 9. This is because the binder resin and the solvent are vaporized at the time of drying and firing, and are not substantially contained in the completed sealing portion 4.

[0078] In addition, regarding the volume content ratio among the solid components, the sum of the true volumes of the constituent elements of the above three solid components is taken as a reference (denominator) to calculate. This is because it is considered that the sealing portion 4 does not substantially contain voids. In the present specification, in the description of the "volume content ratio" related to "solid components", even if simply described as "volume content ratio", it means "volume content ratio among the solid components". The volume content ratio is a content ratio based on volume, and the unit is vol%. Note that, in the present specification, vol% is sometimes simply expressed as "%".

[0079] The volume content ratio of the glass beads 9 in the solid component is 10% or more and 35% or less. Further, it is desirable that the volume content ratio of the particles of the low-melting glass 7 in the solid component be greater than the volume content ratio of the low-thermal expansion filler particles 8 in the solid component.

[0080] Further, in terms of the size of the glass beads 9 in the solid component, the average diameter (D 50 ) of the glass beads 9 is preferably 50 μm or more and 200 μm or less, in consideration of the thickness of the interval (i.e., the height of the spacer 3, the sealing portion 4) between the first glass substrate 1 and the second glass substrate 2 of the vacuum heat-insulating multi-layer glass panel. This is because, generally, the thickness of the interval (i.e., the height of the spacer 3, the sealing portion 4) between the first glass substrate 1 and the second glass substrate 2 of the vacuum heat-insulating multi-layer glass panel is usually in the range of 100 to 300 μm.

[0081] The volume content ratio of the glass beads 9 in the solid component is 10% or more and 35% or less. Further, it is desirable that the volume content ratio of the particles of the low-melting glass 7 in the solid component be greater than the volume content ratio of the low-thermal expansion filler particles 8 in the solid component.

[0082] As the binder resin included in the sealing material paste, in consideration of the influence on the softening flowability, crystallization, etc. of the above-described low-melting glass 7, any one or more of ethyl cellulose, nitrocellulose, and aliphatic polycarbonate is preferable. Further, in terms of the solvent, likewise in consideration of the influence on the low-melting glass 7, any one or more of butyl carbitol acetate, a terpene-based solvent, and propylene carbonate is preferable.

[0083] By applying the above-described sealing material paste to the sealing portion 4 of the vacuum heat-insulating multi-layer glass panel, it is possible to lower the sealing temperature, and also to obtain high airtightness and sealing strength. Further, since the spacer 3 can be applied with resin, and the first glass substrate 1 and the second glass substrate 2 can be applied with strengthened glass, it is possible to improve the heat-insulating property, mass productivity, and reliability of the vacuum heat-insulating multi-layer glass panel.

[0084] (Method for manufacturing vacuum heat-insulating multi-layer glass panel)

[0085] Using Figures 3A-7B An exhaust pipe method, which is one example of a series of manufacturing methods for a representative vacuum multi-layer glass panel, will be described.

[0086] Figure 3A A sectional view of a part of the sealing material paste is shown.

[0087] Figure 3B A sectional view of a part of the sealing material paste is shown. Figure 3A A sectional view of a part of the sealing material paste is shown.

[0088] Figure 4 is a perspective view showing the state in which a thermal radiation reflective film and spacers are formed.

[0089] Figure 4B for Figure 4A Cross-sectional view.

[0090] Figure 5A A cross-sectional view showing the state of the two glass substrates combined.

[0091] Figure 5B A cross-sectional view showing the state in which the two glass substrates are fixed.

[0092] Figure 6A A cross-sectional view showing the process of depressurizing the internal space of a vacuum multilayer glass panel.

[0093] Figure 6B for Figure 6A A partially enlarged cross-sectional view.

[0094] Figure 7A A cross-sectional view showing the state in which the internal space of a vacuum multilayer glass panel is sealed.

[0095] Figure 7B for Figure 7A A partially enlarged cross-sectional view.

[0096] Figure 8A A coordinate graph showing the temperature distribution during the process of removing the adhesive resin from the sealant paste.

[0097] Figure 8B A coordinate graph showing the temperature distribution when the sealing part is heated during the process of depressurizing the internal space of a vacuum multilayer glass panel.

[0098] First, such as Figure 3A As shown, a sealant paste 13 is applied to the periphery of the first glass substrate 1, which has vent holes 10 and vent pipes 11, using a dispenser 12. Then, it is dried on a hot plate at about 150°C for 30 minutes to evaporate and remove the solvent from the sealant paste 13.

[0099] Subsequently, according to Figure 8A The temperature distribution shown decomposes and removes the adhesive resin of the sealant paste. Subsequently, the sealant 14 is fired onto the first glass substrate 1 by softening and flowing the low-melting-point glass 7 particles contained in the sealant paste 13.

[0100] Regarding its firing conditions, such as Figure 8A As shown, the heating and cooling rates in the atmosphere are set to 2°C / minute. During the heating process, the yield point M of the low-melting-point glass 7 is measured. g and softening point T sThe adhesive resin is temporarily maintained at a certain temperature T1 for about 30 minutes to decompose and remove it. Afterwards, the temperature is raised again to a temperature higher than the softening point T. s A certain temperature T2, which is 20 to 40°C higher, is maintained for about 30 minutes, thereby forming a sealing material 14 at the periphery of the first glass substrate 1.

[0101] After the aforementioned process, the sealant paste 13 is transformed into sealant 14.

[0102] On the other hand, in the second glass substrate 2, such as Figure 4A and Figure 4B As shown, a thermal radiation reflective film 6 is formed on a single surface using a vapor deposition method. Then, a plurality of spacers 3 are attached to the surface of the thermal radiation reflective film 6.

[0103] Next, as Figure 5A As shown, the first glass substrate 1 and the second glass substrate 2, fabricated in the above process, are aligned and overlapped (fitted). Then, as... Figure 5B As shown, it is fixed with heat-resistant clips 15, etc.

[0104] Take it as Figure 6A As shown, an electric heater 17 is installed inside the vacuum exhaust furnace 16, and the exhaust pipe 11 is connected to the vacuum pump 18.

[0105] With Figure 8B The sealing temperature distribution shown is achieved by first heating at atmospheric pressure to the yield point M of the low-melting-point glass 7 contained in the sealing material 14. g and softening point T s Maintain a constant temperature T3 for approximately 30 minutes. Afterward, while... Figure 6A and Figure 6B The exhaust port 10 and exhaust pipe 11 shown exhaust the internal space 5 while heating it to a temperature lower than the softening point T. s A temperature T4 that is 10 to 30°C higher. As a result, a sealing part 4 is formed at the periphery using sealing material 14, while the internal space 5 is made into a vacuum state.

[0106] Next, as Figure 7A and 7B As shown, by burning off the exhaust pipe 11 with an electric heater 17 during or after cooling, the vacuum state of the internal space 5 can be maintained.

[0107] As described above, vacuum-insulated multi-layered glass panels are manufactured.

[0108] Example

[0109] Hereinafter, the present application is further explained in detail based on specific examples. However, the present application is not limited to the examples set forth herein, including variations thereof.

[0110] In order to produce the vacuum insulated multilayer glass panel of the present application, first, 42 kinds of lead-free low melting point glasses for producing a paste of a sealing material thereof were trial-produced.

[0111] Table 1 shows the composition and properties of the trial-produced lead-free low melting point glasses.

[0112] Table 1

[0113]

[0114] These lead-free low melting point glasses G-01 to G-42 take into account the environmental and safety problems of substantially containing no harmful lead or the like.

[0115] As the glass raw materials, the powders of V2O5 manufactured by Shin-Etsu Chemical, TeO2 manufactured by High Purity Chemical Laboratory, Ag2O manufactured by Nippon Light Metal, WO3 manufactured by High Purity Chemical Laboratory, BaCO3 manufactured by High Purity Chemical Laboratory, K2CO3 manufactured by High Purity Chemical Laboratory, P2O5 manufactured by High Purity Chemical Laboratory, Al2O3 manufactured by High Purity Chemical Laboratory, Fe2O3 manufactured by High Purity Chemical Laboratory, Y2O3 manufactured by High Purity Chemical Laboratory, La2O3 manufactured by High Purity Chemical Laboratory, and ZnO manufactured by High Purity Chemical Laboratory were used.

[0116] The glass raw materials were weighed, mixed, and combined in a manner so as to total about 200 to 300 g, and were charged into a platinum crucible or a quartz crucible. This was set in a glass melting furnace (electric furnace), and was heated to 750 to 950°C at a temperature increase rate of about 10°C / min, and was stirred with an alumina rod for 1 hour in order to make the molten liquid in the crucible uniform. Thereafter, the crucible was taken out of the glass melting furnace, and the molten liquid in the crucible was caused to flow into a stainless steel plate, and the lead-free low melting point glasses G-01 to 42 shown in Table 1 were respectively produced.

[0117] For the V2O5-TeO2-based lead-free low melting point glasses G-01 to G-09, a platinum crucible was used, and for the V2O5-TeO2-Ag2O-based lead-free low melting point glasses G-10 to G-42, a quartz crucible was used. In addition, G-01 to G-09 were melted at 950°C, G-10 to G-19 were melted at 850°C, and G-20 to G-42 were melted at 750°C.

[0118] The density, the characteristic temperature, and the coefficient of thermal expansion of the respectively trial-produced lead-free low melting point glasses G-01 to G-42 were measured. As for the characteristic temperature, differential thermal analysis (DTA) of glass powder was performed. Here, in order to clearly show the characteristic points of the DTA curve peculiar to the glass, a macrocell was used.

[0119] Figure 9 An example of a DTA curve of a representative glass is shown.

[0120] In Figure 9 , the onset temperature of the first endothermic peak is the glass transition point T g , the endothermic peak temperature is the yield point M g , and the second endothermic peak temperature is the softening point T s . Generally, these characteristic temperatures are determined by the tangent method. Each characteristic temperature is defined by the viscosity of the glass, T g is the temperature corresponding to a viscosity of 1012 13.3 , M g is the temperature corresponding to a viscosity of 1010 11.0 , and T s is the temperature corresponding to a viscosity of 1010 7.65 .

[0121] Next, the trial-produced lead-free low-melting glasses G-01 to G-42 were pulverized to an average particle diameter (D 50 ) of about 1 to 3 μm using a jet mill, and used in the sealing material paste. Note that the average particle diameter (D 50 ) of the lead-free low-melting glass was measured using a laser diffraction / scattering type particle size distribution measuring device LA-950V2 manufactured by Otsuka Electronics Co., Ltd.

[0122] Table 2 and Table 3 show the low-thermal expansion filler particles and the spherical glass beads used in the sealing material paste of the present application.

[0123] The low-thermal expansion filler particles were used in a particle diameter (D 50 ) of 5 to 15 μm. The average particle diameter (D 50 ) was measured using a laser diffraction / scattering type particle size distribution measuring device LA-950V2 manufactured by Otsuka Electronics Co., Ltd. The spherical glass beads were classified using a sieve to obtain the desired size range. The average diameter (D 50 ) was measured using a laser diffraction / scattering type particle size distribution measuring device LA-950V2 manufactured by Otsuka Electronics Co., Ltd.

[0124] Table 2

[0125] Table 2 Density and thermal expansion coefficient of low-thermal expansion filler particles

[0126]

[0127] Table 3

[0128] Table 3 Density and thermal expansion coefficient of spherical glass beads

[0129]

[0130] A sealing material paste was produced using the particles of the lead-free low-melting glass of Table 1, the low-thermal expansion filler of Table 2, the spherical glass beads of Table 3, a resin binder, and a solvent.

[0131] As the binder resin, ethyl cellulose or nitrocellulose was used when the lead-free low-melting glass G-01 to G-09 was used, and an aliphatic polycarbonate was used when the lead-free low-melting glass G-10 to G-42 was used. As the solvent, butyl carbitol acetate was used when the lead-free low-melting glass G-01 to G-09 was used, and both propylene carbonate and a terpene-based solvent were used when the lead-free low-melting glass G-10 to G-42 was used.

[0132] [Example 1]

[0133] In this example, a bonded body that simulated the sealing portion of the vacuum insulated multilayer glass of the present application was produced using the sealing material paste of the present application, and the reliability of the bonded portion thereof was evaluated. Specifically, two glass substrates were bonded using the sealing material paste of the present application, and the bonding strength of the bonded body thereof was evaluated using a shear stress. As a comparative example, a sealing material paste that did not contain spherical glass beads was used, and the effectiveness of the glass beads was confirmed based on this.

[0134] The production method of the bonded body in this example is shown in Figures 10A-11B .

[0135] Figure 10A A schematic perspective view showing the state in which the sealing material paste and the spacer are disposed on the glass substrate as part of the production method of the bonded body that simulates the sealing portion of the vacuum insulated multilayer glass panel.

[0136] Figure 10B A schematic perspective view showing the process of overlapping another glass substrate on the glass substrate of Figure 10A .

[0137] Figure 11A A schematic cross-sectional view showing the process of pressing the two glass substrates after the process of Figure 10B .

[0138] Figure 11B A schematic cross-sectional view showing the state at the end of the process of Figure 11A .

[0139] As the glass substrates 101, 102, a very general soda-lime glass having a thickness of 5 mm was used. As the glass substrate 101, a square size of 20 x 20 mm was used, and as the glass substrate 102, a square size of 10 x 10 mm was used.

[0140] First, as shown in Figure 10AAs shown, the sealing material paste 13 is applied to the top surface of the glass substrate 101 to a diameter of 5 mm and a thickness of about 500 to 600 μm. Further, four spacers 3 having a height of 220 μm are provided. After drying at 150°C for 30 minutes, the glass substrate 102 is attached as shown. Figure 10B As shown, the glass substrate 102 is attached.

[0141] Then, as shown, the glass substrate 102 is attached while applying a load of 3 N from above the glass substrate 102. The joining is performed with the temperature distribution shown. Figure 11A As shown, the glass substrate 102 is attached while applying a load of 3 N from above the glass substrate 102. The joining is performed with the temperature distribution shown. Figure 8A As shown, the glass substrate 102 is attached while applying a load of 3 N from above the glass substrate 102. The joining is performed with the temperature distribution shown. Figure 11B As shown, the glass substrate 102 is attached while applying a load of 3 N from above the glass substrate 102. The joining is performed with the temperature distribution shown.

[0142] Figure 12 The configuration of a device for measuring the joining strength of the joined body obtained by the production method described above is shown.

[0143] As shown in the figure, the joined body composed of the glass substrates 101 and 102 and the sealing material 14 and the spacers 3 interposed therebetween is fixed to a joined body fixing jig 52. Then, an external force is applied to the glass substrate 102 in the lateral direction using a shearing jig 51. At this time, the lower end portion of the shearing jig 51 is positioned at a position 500 μm from the top surface of the glass substrate 101. Further, the moving speed of the shearing jig 51 is set to 34 μm / sec.

[0144] The joining strength of each of the joined bodies obtained by the production method described above is measured under the conditions described above, and the average value (average joining strength) is calculated. By comparing the average values, the advantages of the sealing material paste are evaluated.

[0145] In the case of the sealing material paste used in this embodiment, as the solid component, the lead-free low-melting glass G-01 to G-42 shown in Table 1, the low-thermal expansion filler particles F-01 shown in Table 2, and the spherical glass beads B-14 shown in Table 3 are contained. The volume content of the lead-free low-melting glass G-01 to G-42 and the low-thermal expansion filler particles F-01 in the solid component is determined taking into account the thermal expansion of the soda-lime glass used in the glass substrates 101 and 102. Further, the volume content of the spherical glass beads B-14 in the solid component is set to 20 to 30 vol%. Thus, the joined bodies of each of the five examples are produced one by one, and the average joining strength is calculated.

[0146] Table 4 shows the volume content of the solid component of the sealing material paste, the joining conditions thereof, and the joining strength improvement rate of the joined bodies produced.

[0147] It should be noted that the bond strength improvement rate of joints A-01 to A-42 is based on the case where the solid composition does not contain spherical glass beads B-14. That is, the value is calculated by subtracting the average bond strength of the comparative examples from the average bond strength of the joints of the embodiments as the numerator, using the average bond strength of the comparative examples as the denominator. In the case of the comparative examples, i.e., without spherical glass beads B-14, all joints exhibit an average bond strength of approximately 10 to 20 MPa using a shear stress gauge. Furthermore, within this range, the softening point T is used to measure the average bond strength. s The higher the lead-free, low-melting-point glass, the greater its tendency to become larger.

[0148] Table 4

[0149]

[0150] As can be seen from this table, for the joints A-01 to A-42 of the embodiments containing spherical glass beads B-14, the average joint strength is improved compared to the comparative examples.

[0151] When observing the fracture sites of the comparative example joints, it was found that in almost all joints, the following was observed: Figure 12 The sealant 14 is shown as being broken in a state where it is divided vertically, i.e., broken approximately at the center of the 220 μm joint thickness. In contrast, when observing the damaged portions of joints A-01 to A-42 in embodiments containing spherical glass beads B-14, it was confirmed that in all joints, the propagation of cracks in the sealant 14 was suppressed due to the presence of the spherical glass beads B-14. This is believed to be the reason for the increased joint strength.

[0152] Therefore, it can be seen that incorporating spherical glass beads into sealing materials or their pastes is effective in improving the strength, i.e., the reliability, of the joint. Clearly, this can be effectively applied to the airtight sealing of vacuum-insulated multilayer glass at low temperatures.

[0153] [Example 2]

[0154] In this embodiment, the effect of the volume content of spherical glass beads in the solid component of the sealant paste on the bond strength was prepared in the same manner as in Example 1. Figure 11B The bonding bodies were investigated by evaluating their average bonding strength. A sealant paste was prepared using lead-free low-melting-point glass (G-08, G-10, G-25, G-36, and G-42 from Table 1), low thermal expansion filler particles (F-01 from Table 2), spherical glass beads (B-14 from Table 3).

[0155] Note that, as with Example 1, the ratio of the volume content of the low-melting lead-free glass G-08, G-10, G-25, G-36, and G-42, and the low-thermal expansion filler particles F-01 was set to a constant after taking into account the thermal expansion of the glass substrates 101 and 102, and the volume content of the spherical glass beads B-14 was changed. The low-melting lead-free glass G-25, G-36, and G-42 have a larger coefficient of thermal expansion than G-08 and G-10, and therefore, in order to match the thermal expansion of the glass substrates 101 and 102, it was necessary to decrease the volume content of the low-melting lead-free glass and, in addition, increase the volume content of the low-thermal expansion filler particles.

[0156] Figure 13 A graph showing the relationship between the increase rate of the bonding strength of the bonded body and the volume content of the spherical glass beads B-14 in the solid component of the sealing material paste.

[0157] As shown in this graph, regardless of which low-melting lead-free glass was used, when the volume content of the spherical glass beads B-14 was less than 10 vol%, almost no effect of increasing the bonding strength was confirmed. When the volume content of the glass beads was 10 to 20 vol%, the bonding strength increased as the volume content increased, and had a maximum value in the range of 20 to 30 vol%. When it exceeded 30 vol%, the bonding strength decreased. Note that even when it exceeded 30 vol%, the increase rate of the bonding strength was positive up to 35 vol%, and the bonding strength was higher than when the spherical glass beads B-14 were not contained.

[0158] In terms of the bonding strength at 40 vol%, when the low-melting lead-free glass G-08 or G-10 was used, it was almost the same as when the spherical glass beads B-14 were not contained, and when the low-melting lead-free glass G-25, G-36, and G-42 was used, it was lower than when the spherical glass beads B-14 were not contained. In addition, even when it exceeded 40 vol%, the bonding strength decreased. This is believed to be because the volume content of the low-melting lead-free glass was not sufficient when bonding between the glass substrates 101 and 102 and the spherical glass beads. In addition, for this reason, it is believed that the volume content of the low-melting lead-free glass was smaller when G-25, G-36, or G-42 was used than when G-08 or G-10 was used, and when the volume content of the spherical glass beads B-14 exceeded 35 vol%, the decrease rate of the bonding strength was large. It is believed that the volume content of the low-melting lead-free glass in the solid component of the sealing material paste needs to be at least 35 vol% or more.

[0159] As above, in the sealing material paste, the volume content ratio of the glass beads is preferably 10 to 35 vol%, and particularly effective is 20 to 30 vol%. In addition, the volume content ratio of the lead-free low-melting glass is preferably 35 vol% or more. In addition, it is easy to presume that this result is effectively reflected when applied to low-temperature airtight sealing of a vacuum insulation multilayer glass panel.

[0160] Further, in the present embodiment, regarding F-02 to F-04 other than the low-thermal expansion filler particles F-01 of Table 2, the same joint body as above was produced, and evaluation and discussion were performed.

[0161] As shown in Table 2, the low-thermal expansion filler particles F-01 and F-03 have a large negative coefficient of thermal expansion. In addition, the low-thermal expansion fillers F-02 and F-04 have a coefficient of thermal expansion close to zero. In general, the smaller the coefficient of thermal expansion of the low-thermal expansion filler particles, the easier it is to match the coefficient of thermal expansion of the glass substrates 101, 102. Moreover, in such a case, it is effective to increase the volume content ratio of the lead-free low-melting glass. In this regard, in Table 2, F-03 having the smallest coefficient of thermal expansion is the most effective low-thermal expansion filler particle.

[0162] However, when F-03 is compared with the low-thermal expansion filler particles F-01, the wettability with all of the lead-free low-melting glasses G-01 to G-42 of the V2O5-TeO2 system and the V2O5-TeO2-Ag2O system shown in Table 1 is insufficient, and thus it is difficult to obtain a dense joint. In addition, it is difficult to obtain a desired low coefficient of thermal expansion. Therefore, even if spherical glass beads are introduced, it is difficult to obtain the effect of improving the joint strength as expected.

[0163] Research was also performed on the low-thermal expansion filler particles F-04, and as a result, the coefficient of thermal expansion was not as small as that of the low-thermal expansion filler particles F-03, but the same result was obtained. In the case of using the low-thermal expansion filler particles F-03, F-04, it is considered that surface treatment for improving the wettability with the V2O5-TeO2 system lead-free low-melting glass and the V2O5-TeO2-Ag2O system lead-free low-melting glass shown in Table 1 needs to be performed on the surface of the filler particles.

[0164] The low-thermal expansion filler particles F-02 have good wettability with the V2O5-TeO2 system lead-free low-melting glass and the V2O5-TeO2-Ag2O system lead-free low-melting glass compared with the low-thermal expansion filler particles F-03, F-04. However, the coefficient of thermal expansion of F-02 as low-thermal expansion filler particles is not that small.

[0165] When using V2O5-TeO2-Ag2O series lead-free low-melting-point glass with a very high coefficient of thermal expansion as a sealing material paste, the use of low-thermal-expansion filler particles with a negative coefficient of thermal expansion, F-01, is effective among the low-thermal-expansion filler particles shown in Table 2. Clearly, this result can also be effectively applied to the low-temperature hermetically tight sealing of vacuum-insulated multilayer glass panels.

[0166] [Example 3]

[0167] In this embodiment, regarding the average particle size (D) of the spherical glass beads in the solid component of the sealant paste... 50 The effect on the bond strength is similar to that in Example 1, and is fabricated as follows: Figure 11B The average joint strength of the joint shown was evaluated. However, as... Figure 11B The spacer 3 shown is made of metal with a height of 250 μm. In addition, the coating thickness of the sealing material paste 13 is increased to more than 600 μm.

[0168] As lead-free low-melting-point glasses, G-07, G-12, G-24, G-34, and G-39 from Table 1 were used as low-thermal-expansion filler particles, F-01 from Table 2 was used as spherical glass beads, and B-11 to B-15 from Table 3 were used to prepare a sealing material paste. It should be noted that the volume content ratio of lead-free low-melting-point glasses G-07, G-12, G-24, G-34, and G-39 to low-thermal-expansion filler particles F-01 was the same as in Example 1, determined after considering the thermal expansion of glass substrates 101 and 102.

[0169] The spherical glass beads B-11 to B-15, as shown in Table 3, are all made of soda-lime glass from the same raw material as the glass substrates 101 and 102. Regarding their average particle size (D... 50 For example, B-11 has a diameter of 46 μm, B-12 has a diameter of 88 μm, B-13 has a diameter of 125 μm, B-14 has a diameter of 143 μm, and B-15 has a diameter of 184 μm. The height of spacer 3, 250 μm, is taken into account the maximum particle size of the spherical glass beads, specifically the average particle size (D). 50 The maximum particle size of B-15 is determined by the largest particle size. In addition, the volume content of spherical glass beads B-11 to B-15 is set to 30% by volume when using lead-free low melting point glass G-07 or G-24, 25% by volume when using G-12, and 20% by volume when using G-34 or G-39.

[0170] Figure 14 To illustrate the increase in joint strength of the joint compared to the average particle size (D) of the spherical glass beads contained in the sealant paste. 50The graph shows the relationship between the volumetric and non-volume components of the glass beads. The areas within square brackets [] represent the volumetric content of the spherical glass beads.

[0171] When using all lead-free low-melting-point glass, the average particle size (D) of the spherical glass beads is... 50 When the diameter is less than 100 μm, the effect on improving the bonding strength is small. On the other hand, in D... 50 With a thickness of 125 μm, a significant improvement in bonding strength is achieved.

[0172] When observing the fracture site of the conglomerate, the average particle size (D) of the spherical glass beads... 50 When the size is less than 100 μm, almost all of them exhibit the following characteristics: Figure 12 The sealing material 14 shown is in a state of damage from top to bottom, that is, damage occurs approximately from the center of the 250 μm bonding thickness. The average particle size (D) of the spherical glass beads... 50 When the thickness of the joint is more than half of 250 μm, exceeding 125 μm, it is confirmed that the propagation of cracks in the sealing material 14 is suppressed due to the spherical glass beads.

[0173] As can be seen from the above, to improve the bonding strength of the joint, the average particle size (D) of the spherical glass beads is increased. 50 A thickness of more than half the joint thickness is effective. Furthermore, it is easy to infer that this result will be effectively reflected in the cryogenic hermetic sealing of vacuum-insulated multilayer glass panels. In vacuum-insulated multilayer glass panels, the spacing between the two glass substrates (i.e., the height of the spacer and the thickness of the seal) is typically in the range of 100–300 μm; therefore, the average diameter (D) of the spherical glass beads is also relevant. 50 A value between 50μm and 200μm is suitable.

[0174] [Example 4]

[0175] In this embodiment, the effect of different raw materials for the spherical glass beads in the solid component of the sealant paste on the bonding strength was handled in the same manner as in Example 1. Figure 11B The average bond strength of the joint was evaluated.

[0176] As the lead-free low-melting glass, G-05, G-17, G-33 and G-40 of Table 1 were used, as the low-thermal expansion filler particles, F-01 of Table 2 was used, and as the spherical glass beads, B-14, B-21 and B-31 of Table 3 were used, a sealing material paste was prepared. The spherical glass beads B-14, B-21 and B-31 were different in raw material as shown in Table 3, but were classified using the same sieve to have a size of 75 μm or more and less than 212 μm. The raw material of each of the spherical glass beads was, B-14 was soda-lime glass, B-21 was borosilicate glass, and B-31 was quartz glass. Thus, even if the range of particle diameter was the same, the physical values such as density and coefficient of thermal expansion were different, because the raw materials were different. The coefficient of thermal expansion of the spherical glass beads was different, and therefore, in this embodiment, the volume content of each solid component in the sealing material paste was determined in consideration of the thermal expansion of the glass substrates 101 and 102.

[0177] Table 5 shows the volume content of the solid components of the sealing material paste, the bonding conditions thereof and the bonding strength improvement rate of the bonded body prepared. Note that the bonding strength improvement rate of the bonded bodies A-05a to A-05c, A-17a to A-17c, A-33a to A-33c and A-40a to A-40c is a value based on the average bonding strength of the bonded body prepared using a sealing material paste containing the lead-free low-melting glass G-05, G-17, G-33 or G-40 and the low-thermal expansion filler particles F-01, which is a comparative example in which the spherical glass beads are not contained as the solid component. The volume contents of the lead-free low-melting glass and the low-thermal expansion filler particles were determined in consideration of the thermal expansion of the soda-lime glass used for the glass substrates 101 and 102.

[0178] Table 5

[0179]

[0180] In all of the bonded bodies A-05a to A-05c, A-17a to A-17c, A-33a to A-33c and A-40a to A-40c, the effect of the content of the spherical glass beads B-14 made of soda-lime glass was the largest in terms of the improvement of the bonding strength, when the type of the lead-free low-melting glass was the same. The spherical glass beads B-21 made of borosilicate glass had the next largest effect.

[0181] In terms of the content of the spherical glass beads B-31 made of quartz glass, in the bonded bodies A-5c and A-17c, the effect of the improvement of the strength was hardly confirmed, and in the bonded bodies A-33c and A-40c, the result was that the bonding strength was rather decreased.

[0182] To investigate the reason, the bonding portion cross section of the bonded body before the bonding strength test was observed using an electron microscope. As a result, it was found that a crack had been generated in the lead-free low melting point glass in the vicinity of the interface of the quartz glass spherical glass beads B-31 after bonding. It is considered that this is because the thermal expansion of the quartz glass spherical glass beads B-31 is very small, and the difference in thermal expansion from the lead-free low melting point glass is very large, and thus a crack is generated.

[0183] In the case where the particle diameter is very small like the low thermal expansion filler particles, the generation of such a crack was not confirmed. From this, it is understood that when the spherical glass beads are introduced, the thermal expansion of not only the glass substrates 101, 102 as the bonded material but also the difference in thermal expansion from the spherical glass beads must be considered.

[0184] According to the above, the spherical glass beads in the sealing material paste are the same glass-based raw material as the glass substrates 101, 102, and this is most effective for the bonding strength improvement of the bonded body. Next, it is understood that the effect of bonding strength improvement is also obtained in similar glass-based raw materials. This is based on the matching (integration) of the thermal expansion of the glass substrates 101, 102 and the spherical glass beads. It also has the following result: it is suggested that the coefficient of thermal expansion of the spherical glass beads in the sealing material paste is effective within the range of ± 15 x 10 -7 / °C with respect to the coefficient of thermal expansion of the glass substrates 101, 102. Obviously, the results of the present embodiment can be effectively applied to the low-temperature airtight sealing of the vacuum thermal insulation multilayer glass.

[0185] [Embodiment 5]

[0186] In the present embodiment, based on the discussion results of the above Embodiments 1 to 4, a vacuum thermal insulation multilayer glass panel shown in FIG. 1 was produced using the sealing material paste containing the lead-free low melting point glass of Table 1, the low thermal expansion filler particles of Table 2, and the spherical glass beads of Table 3. Figure 1A The present invention relates to the vacuum thermal insulation multilayer glass panel shown in FIG. 1, and the thermal insulation and reliability thereof were evaluated. In addition, as a comparative example, a sealing material paste not containing the spherical glass beads of Table 3 was used, and a vacuum thermal insulation multilayer glass panel shown in FIG. 1 was produced in the same manner as above, and the thermal insulation and reliability thereof were evaluated. The comparative example was used for comparison with the vacuum thermal insulation multilayer glass panel of the present embodiment. Note that both the present embodiment and the comparative example were produced in accordance with the manufacturing method of the vacuum thermal insulation multilayer glass panel shown in FIG. 2 and the temperature distribution shown in FIG. 3. Figures 3A-7B Figure 8A and 8B The vacuum thermal insulation multilayer glass panel was produced in accordance with the manufacturing method of the vacuum thermal insulation multilayer glass panel shown in FIG. 2 and the temperature distribution shown in FIG. 3.

[0187] ​In the vacuum heat-insulating multilayer glass panel of the present embodiment and its comparative example, a soda-lime glass substrate of 300 x 300 x 3 mm in size was used for the first glass substrate 1 and the second glass substrate 2, and a metal spacer (stainless steel) of 200 μm in height and 500 μm in outer diameter was used for the spacer 3. The sealing material paste used in the present embodiment contained, as solid components, the lead-free low-melting glass G-08 of Table 1, the low-thermal expansion filler particles F-01 of Table 2, and the spherical glass beads B-13 of Table 3. The respective volume contents in the solid components were 48:27:25 (vol%).

[0188] In addition, the sealing material paste used in the comparative example contained, as solid components, the lead-free low-melting glass G-08 of Table 1 and the low-thermal expansion filler particles F-01 of Table 2. The respective volume contents in the solid components were 64:36 (vol%).

[0189] As for the heat-insulating properties of the vacuum heat-insulating multilayer glass panels produced in the present embodiment and its comparative example, the heat transfer coefficients were all about 0.7 W / m 2 • K, which is good.

[0190] Figure 15 A test device for evaluating the reliability of a vacuum heat-insulating multilayer glass panel is shown.

[0191] The test device shown in the figure has a configuration in which a vacuum heat-insulating multilayer glass panel is disposed in a fluororesin container 19 (formed of PTFE: polytetrafluoroethylene, etc.) of a quadrangular shape via a silicone rubber gasket 20, and a test can be performed. A hot air blower and a cold air blower are provided outside the fluororesin container 19. Two kinds of air at largely different temperatures can be fed into the fluororesin container 19 via a fluororesin tube 21 (formed of PTFE, etc.) of φ 10 mm from either of these. The temperature of the air can be switched using an automatic on-off valve.

[0192] As for the vacuum heat-insulating multilayer glass panels produced in the present embodiment and its comparative example, 80°C hot air and -50°C cold air were alternately blown at a flow rate of 30 L / min for 15 minutes. The case where the hot air and the cold air were blown once each was taken as one cycle, and this was repeated 1000 times. Then, after 1000 times, the heat transfer coefficient was measured, and the like, and the damage state of the sealing portion was evaluated.

[0193] After the above cycle, in the vacuum heat-insulating multilayer glass panel of the comparative example, the sealing portion did not appear to be damaged in appearance, but leaked somewhere, and the heat-insulating properties were completely lost. In the vacuum heat-insulating multilayer glass panel of the present embodiment, the initial heat-insulating properties were maintained, and it was confirmed that the sealing portion was not damaged. It was thus found that the introduction of the spherical glass beads into the sealing portion was effective.

[0194] [Example 6]

[0195] In this example, instead of the lead-free low-melting glass G-08 of Table 1 in the solid component of Example 5, the lead-free low-melting glass G-12 of Table 1 was used. The other constituent elements of the solid component were the low-thermal expansion filler particles F-01 of Table 2 and the spherical glass beads B-13 of Table 3. Using the sealing material paste containing these solid components, a vacuum heat-insulating multilayer glass panel was produced as shown in FIG. 1. Figure 1A The vacuum heat-insulating multilayer glass panel shown was evaluated for heat-insulating properties and reliability. In addition, as a comparative example, a sealing material paste using the solid components of this example except for the spherical glass beads of Table 3 was used to produce a vacuum heat-insulating multilayer glass panel as shown in FIG. 1. Figure 1A The vacuum heat-insulating multilayer glass panel shown was evaluated for heat-insulating properties and reliability. The comparative example was used for comparison with the vacuum heat-insulating multilayer glass panel of this example.

[0196] In addition, the vacuum heat-insulating multilayer glass panel of this example and the comparative example thereof differed from Example 5 in that a spacer 3 of a polyimide resin having a height of 200 μm and an outer diameter of 500 μm was used in this example. In the spacer 3 of the comparative example, as in Example 5, a spacer of the same shape made of metal (stainless steel) was used.

[0197] The volume content ratio of the lead-free low-melting glass G-12, the low-thermal expansion filler particles F-01, and the spherical glass beads B-13 in the solid component of the sealing material paste used in this example was 46:29:25 (vol%). In addition, in the sealing material paste used in the comparative example, the volume content ratio of the lead-free low-melting glass G-12 and the low-thermal expansion filler particles F-01 in the solid component was 61:39 (vol%). The comparative example had the same content ratio of the lead-free low-melting glass G-12 and the low-thermal expansion filler particles F-01 as this example.

[0198] As for the heat-insulating properties of the vacuum heat-insulating multilayer glass panel produced in this example and the comparative example thereof, the heat transfer coefficient of the comparative example was about 0.7 W / m 2 K, while in this example, it was about 0.5 W / m 2 K. That is, the vacuum heat-insulating multilayer glass panel of this example showed superior heat-insulating properties compared to the vacuum heat-insulating multilayer glass panel of the comparative example. This is believed to be because a resin having a thermal conductivity significantly lower than metal was used for the spacer 3.

[0199] The reliability of the vacuum heat-insulating multilayer glass panel produced in this example and the comparative example thereof was evaluated as in Example 5.

[0200] After the same cycle as in Example 5, in the vacuum insulated multilayer glass panel of the comparative example, the seal portion did not look broken in appearance, but a leak occurred, and the heat insulation property was greatly deteriorated. In the vacuum insulated multilayer glass panel of the present example, the initial heat insulation property was maintained, and it was confirmed that the seal portion was not broken. It was thus found that the introduction of the spherical glass beads into the seal portion was effective. In addition, the effectiveness of the spacer made of resin was confirmed.

[0201] [Example 7]

[0202] In the present example, instead of the lead-free low-melting glass G-08 of Table 1 and the spherical glass beads B-13 of Table 3 in the solid component of Example 5, the lead-free low-melting glass G-24 of Table 1 and the spherical glass beads B-12 of Table 3 were used. The other constituent elements of the solid component were the low-thermal expansion filler particles F-01 of Table 2. Using the seal material paste containing these solid components, a vacuum insulated multilayer glass panel as shown in the drawing was produced. Figure 1A The vacuum insulated multilayer glass panel of the present example was evaluated in terms of heat insulation property and reliability. In addition, as a comparative example, a vacuum insulated multilayer glass panel was produced using a seal material paste of the solid component of the present example except for the spherical glass beads of Table 3. Figure 1A The vacuum insulated multilayer glass panel of the present example was evaluated in terms of heat insulation property and reliability. The comparative example was used for comparison with the vacuum insulated multilayer glass panel of the present example.

[0203] In addition, the vacuum insulated multilayer glass panel of the present example and the comparative example thereof was different from Example 5 in that air-cooled strengthened soda-lime glass substrates were used for the first glass substrate 1 and the second glass substrate 2, and a spacer made of polyamide resin having a height of 150 μm and an outer diameter of 300 μm was used for the spacer 3 of the present example. In the comparative example, a spacer made of metal (stainless steel) having the same shape as in the present example was used for the spacer 3.

[0204] The volume content ratio of the lead-free low-melting glass G-24, the low-thermal expansion filler particles F-01, and the spherical glass beads B-12 in the solid component of the seal material paste used in the present example was 46:34:20 (vol%). In addition, in the seal material paste used in the comparative example, the volume content ratio of the lead-free low-melting glass G-24 and the low-thermal expansion filler particles F-01 in the solid component was 57:43 (vol%). The comparative example had the same content ratio of the lead-free low-melting glass G-12 and the low-thermal expansion filler particles F-01 as in the present example.

[0205] In terms of the heat insulation property of the vacuum insulated multilayer glass panel produced in the present example and the comparative example thereof, the heat transfer coefficient of the comparative example was about 0.8 W / m 2 , and in the present example, it was 0.6 W / m 2• K or less. That is, the vacuum multilayer glass panel of the present embodiment showed excellent heat insulation compared to the vacuum multilayer glass panel of the comparative example. This is considered to be due to the use of a resin having a thermal conductivity significantly lower than that of metal for the spacer 3.

[0206] The reliability of the vacuum multilayer glass panel of the present embodiment and its comparative example was evaluated in the same manner as in Example 5.

[0207] After the same cycle as in Example 5, in the vacuum multilayer glass panel of the comparative example, a peeled portion was confirmed in the appearance of the sealing portion, and the heat insulation was significantly deteriorated. In the vacuum multilayer glass panel of the present embodiment, on the other hand, the initial heat insulation was maintained, and it was confirmed that the sealing portion was not damaged. It was thus ascertained that the introduction of the spherical glass beads into the sealing portion was effective. In addition, the effectiveness of the resin-made spacer was confirmed. Furthermore, it was known that the air-cooled strengthened glass could be effectively applied to the glass substrate.

[0208] [Example 8]

[0209] In the present embodiment, instead of the lead-free low-melting glass G-08 of Table 1 and the spherical glass beads B-13 of Table 3 in the solid component of Example 5, the lead-free low-melting glass G-25 of Table 1 and the spherical glass beads B-15 of Table 3 were used. The other constituent elements of the solid component were the low-thermal expansion filler particles F-01 of Table 2. Using a sealing material paste containing these solid components, a vacuum multilayer glass panel was produced in the same manner as in Example 5. Figure 1A The vacuum multilayer glass panel of the present embodiment was evaluated in terms of heat insulation and reliability. In addition, as a comparative example, a vacuum multilayer glass panel was produced using a sealing material paste of the solid component of the present embodiment except for the spherical glass beads of Table 3. Figure 1A The vacuum multilayer glass panel of the present embodiment was evaluated in terms of heat insulation and reliability. The comparative example was used for comparison with the vacuum multilayer glass panel of the present embodiment.

[0210] In addition, the vacuum multilayer glass panel of the present embodiment and its comparative example differed from Example 5 in that a chemically strengthened soda-lime glass substrate was used for the first glass substrate 1 and the second glass substrate 2, and a spacer made of a fluororesin containing ceramic particles having a height of 250 μm and an outer diameter of 500 μm was used for the spacer 3 of the present embodiment. Here, the ceramic particles were AI2O3 particles. In order to prevent the resin-made spacer from being deformed at the time of airtight sealing, the ceramic particles were dispersed in the resin-made spacer. In the spacer 3 of the comparative example, a spacer made of metal (stainless steel) having the same shape as in the present embodiment was used.

[0211] The volume content ratio of the lead-free low-melting glass G-25, the low-thermal expansion filler particles F-01, and the spherical glass beads B-15 in the solid components of the sealing material paste used in this example was 40:30:30 (vol%). In addition, in the sealing material paste used in the comparative example, the volume content ratio of the lead-free low-melting glass G-25 and the low-thermal expansion filler particles F-01 in the solid components was 57:43 (vol%). The comparative example had the same content ratio of the lead-free low-melting glass G-25 and the low-thermal expansion filler particles F-01 as this example.

[0212] As for the heat insulation property of the vacuum insulated multilayer glass panel produced in this example and the comparative example thereof, the heat transfer coefficient of the comparative example was 0.7 W / m 2 K or so, while in this example, it was 0.4 W / m 2 K or so. That is, the vacuum insulated multilayer glass panel of this example showed superior heat insulation property compared to the vacuum insulated multilayer glass panel of the comparative example. This is considered to be due to the use of resin having a thermal conductivity significantly lower than that of metal for the spacer 3.

[0213] In the vacuum insulated multilayer glass panel of the comparative example, several peeled parts were confirmed in the sealing portion in terms of appearance, and the heat insulation property was greatly deteriorated. In the vacuum insulated multilayer glass panel of this example, the initial heat insulation property was maintained, and it was confirmed that the sealing portion was not damaged. It was thus ascertained that the introduction of the spherical glass beads into the sealing portion was effective. In addition, the effectiveness of the resin-made spacer in which ceramic particles were dispersed was confirmed. Furthermore, it was known that chemically strengthened glass could be effectively applied to the glass substrate.

[0214] [Example 9]

[0215] In this example, instead of the lead-free low-melting glass G-08 of Table 1 in the solid components of Example 5, the lead-free low-melting glass G-22 of Table 1 was used. The other components of the solid components were the low-thermal expansion filler particles F-01 of Table 2 and the spherical glass beads B-13 of Table 3. Using a sealing material paste containing these solid components, two kinds of Figure 1A The vacuum insulated multilayer glass panel of the present application shown was evaluated for its heat insulation property and reliability. In addition, as a comparative example, a sealing material paste in which the solid components of this example 5 were used except for the spherical glass beads of Table 3 was used to produce Figure 1A The vacuum insulated multilayer glass panel of the present application shown was evaluated for its heat insulation property and reliability. In addition, as a comparative example, a sealing material paste in which the solid components of this example 5 were used except for the spherical glass beads of Table 3 was used to produce

[0216] Further, the vacuum heat-insulating multilayer glass panel of the present embodiment and its comparative example differ from Embodiment 5 in that two kinds of spacers 3, an epoxy resin spacer containing glass particles having a height of 200 μm and an outer diameter of 500 μm and a phenoxy resin spacer containing glass particles having a height of 200 μm and an outer diameter of 500 μm, are used in the present embodiment. Here, the glass particles are SiO2particles. In order to prevent the resin spacer from deforming at the time of airtight sealing, the glass particles are dispersed in the resin spacer. In the comparative example, a metal spacer (stainless steel) having the same shape as the present embodiment is used for the spacer 3.

[0217] The volume content ratio of the lead-free low-melting glass G-22, the low-thermal expansion filler particles F-01, and the spherical glass beads B-13 in the solid components of the sealing material paste used in the present embodiment is 42:38:20 (vol%). In addition, in the sealing material paste used in the comparative example, the volume content ratio of the lead-free low-melting glass G-22 and the low-thermal expansion filler particles F-01 in the solid components is 53:47 (vol%). The comparative example has the same content ratio of the lead-free low-melting glass G-22 and the low-thermal expansion filler particles F-01 as the present embodiment.

[0218] As for the heat-insulating properties of the vacuum heat-insulating multilayer glass panel produced in the present embodiment and its comparative example, the comparative example has a heat transfer coefficient of about 0.8 W / m 2 K, while the present embodiment has both about 0.5 W / m 2 K. That is, the vacuum heat-insulating multilayer glass panel of the present embodiment exhibits superior heat-insulating properties compared to the vacuum heat-insulating multilayer glass panel of the comparative example. This is considered to be because the resin having a thermal conductivity significantly lower than that of metal is used for the spacer 3.

[0219] In the vacuum heat-insulating multilayer glass panel of the comparative example, several peeling sites are confirmed in the appearance of the sealing portion, and the heat-insulating properties are greatly deteriorated. In the vacuum heat-insulating multilayer glass panel of the present embodiment, the initial heat-insulating properties are maintained, and it is confirmed that the sealing portion is not damaged. It is thus ascertained that the introduction of the spherical glass beads into the sealing portion is effective. In addition, the effectiveness of the resin spacer containing glass particles is confirmed.

[0220] [Embodiment 10]

[0221] In the present embodiment, instead of the lead-free low-melting glass G-08 of Table 1 in the solid components of Embodiment 5, the lead-free low-melting glass G-42 of Table 1 is used. The other components of the solid components are the low-thermal expansion filler particles F-01 of Table 2 and the spherical glass beads B-13 of Table 3. Using a sealing material paste containing these solid components, a vacuum heat-insulating multilayer glass panel is produced. Figure 1AThe present application relates to a vacuum heat-insulating multilayer glass panel, and its heat-insulating property and reliability were evaluated. In addition, as comparative examples, vacuum heat-insulating multilayer glass panels were produced using sealing material pastes in which the solid components of the present embodiment were changed to those of the comparative examples, except for the spherical glass beads of Table 3. Figure 1A Figure 1A The vacuum heat-insulating multilayer glass panel was evaluated for its heat-insulating property and reliability. The comparative examples were used for comparison with the vacuum heat-insulating multilayer glass panel of the present embodiment.

[0222] In addition, the vacuum heat-insulating multilayer glass panel of the present embodiment and its comparative examples differed from that of Example 5 in that air-cooled strengthened soda-lime glass substrates were used for the first glass substrate 1 and the second glass substrate 2, and a spacer made of silicone resin containing glass particles having a height of 200 μm and an outer diameter of 500 μm was used for the spacer 3 of the present embodiment. Here, the glass particles were SiO2particles. In order to prevent the resin spacer from deforming at the time of airtight sealing, the glass particles were dispersed in the resin spacer. In the spacer 3 of the comparative examples, a spacer made of metal (stainless steel) having the same shape as that of the present embodiment was used.

[0223] The volume content ratio of the lead-free low-melting glass G-42, the low-thermal expansion filler particles F-01, and the spherical glass beads B-13 in the solid components of the sealing material paste used in the present embodiment was 43:32:25 (vol%). In addition, in the sealing material paste used in the comparative examples, the volume content ratio of the lead-free low-melting glass G-42 and the low-thermal expansion filler particles F-01 in the solid components was 57:43 (vol%). The comparative examples had the same content ratio of the lead-free low-melting glass G-42 and the low-thermal expansion filler particles F-01 as the present embodiment.

[0224] As for the heat-insulating property of the vacuum heat-insulating multilayer glass panel produced in the present embodiment and its comparative examples, the heat transfer coefficient of the comparative examples was 0.7 W / m 2 ·K or so, while in the present embodiment, both were 0.4 W / m 2 ·K or so. That is, the vacuum heat-insulating multilayer glass panel of the present embodiment showed superior heat-insulating property compared to the vacuum heat-insulating multilayer glass panel of the comparative examples. This is believed to be because a resin having a thermal conductivity significantly lower than that of metal was used for the spacer 3.

[0225] In the vacuum heat-insulating multilayer glass panel of the comparative examples, a peeling site was confirmed in the appearance of the sealing portion, and the heat-insulating property was greatly deteriorated. In the vacuum heat-insulating multilayer glass panel of the present embodiment, the initial heat-insulating property was maintained, and it was confirmed that the sealing portion was not damaged. It was thus ascertained that the introduction of the spherical glass beads into the sealing portion was effective. In addition, the effectiveness of the resin spacer in which glass particles were dispersed was confirmed. Furthermore, it was known that air-cooled strengthened glass could be effectively applied to glass substrates.

[0226] According to the above Embodiments 1 to 10, the vacuum heat-insulating multi-pane glass panel of the present application can achieve an airtight seal at low temperatures, and thus is excellent in mass productivity. Moreover, a resin having low thermal conductivity can be used as the spacer, and thus the heat-insulating property is also excellent. Furthermore, since the bonding strength of the sealing portion can be improved, the reliability is also excellent. These mass productivity, heat-insulating property, and reliability can be achieved by using the sealing material paste of the present application.

[0227] Therefore, the vacuum heat-insulating multi-pane glass panel of the present application to which the sealing material paste of the present application is applied can be widely spread to the global housing and building fields and the like, and can contribute greatly to coping with global warming by reducing the amount of CO2 emission through reduction in the amount of energy use.

[0228] Explanation of Reference Signs

[0229] 1: first glass substrate, 2: second glass substrate, 3: spacer, 4: sealing portion, 5: internal space, 6: heat radiation reflection film, 7: low-melting glass, 8: low-thermal expansion filler particles, 9: glass beads, 10: exhaust hole, 11: exhaust pipe, 12: dispenser, 13: sealing material paste, 14: sealing material, 15: heat-resistant clamp, 16: vacuum exhaust furnace, 17: electric heater, 18: vacuum pump, 19: fluorine resin container, 20: silicone rubber gasket, 21: fluorine resin tube, 51: shear clamp, 52: bonded body fixing clamp, 101, 102: glass substrate.

Claims

1. A sealing material comprising: a lead-free low-melting glass particle containing vanadium oxide and tellurium oxide, a low-thermal expansion filler particle, and a glass bead as solid components, a volume content ratio of the glass bead in the solid components is 10% or more and 35% or less, a volume content ratio of the lead-free low-melting glass particle in the solid components is greater than a volume content ratio of the low-thermal expansion filler particle in the solid components, The average diameter D of the glass beads is 50 μm or more and 200 μm or less. 50 50 μm or more and 200 μm or less, the low-thermal expansion filler particle is formed of zirconium tungstate phosphate, the glass bead is formed of soda-lime glass or borosilicate glass, a volume content ratio of the lead-free low-melting glass particle in the solid components is 35% or more and 72% or less.

2. The sealing material of claim 1, wherein, a volume content ratio of the glass bead in the solid components is 20% or more and 30% or less.

3. The sealing material of claim 1 or 2, wherein, the lead-free low-melting glass particle further contains silver oxide.

4. The sealing material of claim 1 or 2, wherein, the lead-free low-melting glass particle further contains one or more of tungsten oxide, barium oxide, potassium oxide, and phosphorus oxide.

5. The sealing material of claim 1 or 2, wherein, the lead-free low-melting glass particle further contains one or more of aluminum oxide, iron oxide, yttrium oxide, and lanthanum oxide.

6. The sealing material according to claim 1 or 2, further comprising a solvent and a binder resin.

7. The sealing material of claim 6, wherein, the binder resin contains one or more of ethyl cellulose, nitrocellulose, and aliphatic polycarbonate.

8. The sealing material of claim 6, wherein, the solvent contains one or more of butyl carbitol acetate, a terpene-based solvent, and propylene carbonate.

9. The encapsulant of claim 1 or 2, wherein, The average particle diameter D of the low thermal expansion filler particles is preferably 3 μm or more and 20 μm or less. 50 is 3 μm or more and 20 μm or less.

10. A multi-layer glass panel comprising: a first glass substrate, a second glass substrate disposed in opposition to the first glass substrate with a prescribed interval, a spacer sandwiched between the first glass substrate and the second glass substrate and maintaining the interval, and a sealing portion sandwiched between the first glass substrate and the second glass substrate; having an internal space surrounded by the first glass substrate, the second glass substrate, and the sealing portion, the spacer being disposed in the internal space, the sealing portion contains the sealing material according to any one of claims 1 to 9.

11. The multi-layer glass panel of claim 10, wherein, The maximum diameter of the glass beads is below the pitch, the average diameter D of the glass beads is 50 more than half of the pitch.

12. The multi-layer glass panel of claim 10 or 11, wherein, a coefficient of thermal expansion of the glass beads is within ±15 x 10 -7 / °C of a coefficient of thermal expansion of the first glass substrate or the second glass substrate.

13. The multi-layer glass panel of claim 10 or 11, wherein, the spacer contains a resin.

14. The multi-layer glass panel of claim 13, wherein, the resin contains one or more of a polyimide resin, a polyamide resin, a fluororesin, an epoxy resin, a phenoxy resin, and a silicone resin.

15. The multi-layer glass panel of claim 13, wherein, the spacer contains a glass particle or a ceramic particle.

16. The multi-layer glass panel of claim 10 or 11, wherein, the first glass substrate or the second glass substrate is formed of a strengthened glass subjected to air-cooling strengthening treatment or chemical strengthening treatment.

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