Sealing material and double glazing panel

Abstract

This sealing material includes: lead-free, low-melting-point glass particles containing a vanadium oxide and a tellurium oxide; and low thermal expansion filler particles having a thermal expansion coefficient lower than that of said glass particles. The low thermal expansion filler particles include fine powder filler particles having an average particle diameter of less than 3 μm or spherical filler particles having an average particle diameter of 10 μm or more.

Description

Sealing materials and double-glazed glass panels

[0001] This invention relates to sealing materials and multi-layer glass panels.

[0002] In recent years, there has been a growing demand for window glass with significantly higher thermal insulation than conventional double-glazed windows. Achieving this requires high thermal insulation through a high vacuum inside the double-glazed window. Furthermore, in order to widely implement this technology globally, development must proceed with careful consideration of manufacturing costs and other factors.

[0003] Achieving a high vacuum in double-glazed windows requires hermetically sealing the two glass panels. Historically, lead-based glass and bismuth-based glass, which can be sealed at temperatures above 450°C, have been used as sealing materials.

[0004] Furthermore, window panes have a tendency to easily crack if temperature differences occur within the panel, so it was necessary to slowly raise and lower the temperature during sealing to prevent temperature distribution. Therefore, sealing at high temperatures of 450°C or higher increased energy costs and yield, leading to higher manufacturing costs.

[0005] Furthermore, depending on the region and building, there is a requirement for the use of tempered glass, which is more resistant to breakage, such as glass that has undergone air-cooling strengthening treatment, to prevent damage due to high vacuum and for security purposes. Tempered glass achieves high strength by forming a compression strengthening layer on its surface. However, the strengthening layer in conventional lead-based low-melting-point glass and bismuth-based low-melting-point glass gradually decreases at heating temperatures above approximately 320°C and disappears at temperatures above approximately 400°C. For this reason, it is difficult to apply tempered glass to panel glass using conventional lead-based low-melting-point glass and bismuth-based low-melting-point glass, which have sealing temperatures above 400°C.

[0006] As described above, lowering the sealing temperature is extremely important for achieving a high vacuum inside a multi-layer glass panel and reducing the cost of the panel.

[0007] Patent Document 1 states that when the components are expressed as oxides, the amount of Ag is 10 to 60% by mass. ２ O and 5-65% by mass of V ２ O ５ and 15-50 mass% TeO２ containing Ag ２ O and V ２ O ５ and TeO ２ The total content of them is 75% by mass or more and less than 100% by mass, and the balance is P ２ O ５ , BaO, K ２ O, WO ３ , Fe ２ O ３ , MnO ２ , Sb ２ O ３ , and ZnO in an amount of more than 0% and 25% by mass or less is disclosed. This Ag ２ O-V ２ O ５ -TeO ２ -based lead-free low melting point glass has a softening point in the temperature range of 268 to 320 °C and softens and flows at a significantly lower temperature than conventional lead-based or bismuth-based low melting point glasses.

[0008] Patent Document 2 discloses a glass sealing material applicable as a sealing material for a glass panel of a flat display device, having no devitrification in the sealing process, and obtaining a high bonding strength, which is a vanadium-based (V ２ O ５ -P ２ O ５ -based) low melting point glass (vanadium phosphate glass) and filler particles. This glass sealing material further contains 0.1 to 1.0% by volume of glass beads. Here, the glass beads function as an aggregate for attaching two panel glasses at equal intervals.

[0009] Japanese Unexamined Patent Application Publication No. 2013-3225 and Japanese Unexamined Patent Application Publication No. 2007-320822

[0010] In the lead-free low melting point glass composition described in Patent Document 1, although it can soften and flow at a significantly lower temperature than conventional lead-based or bismuth-based low melting point glasses, the strength of the glass becomes weaker as the temperature decreases, and there is a risk that sufficient bonding strength cannot be obtained as a multi-layer glass panel.

[0011] When firmly bonding glass substrates using a glass-containing encapsulant, it is necessary to increase the softening and fluidity of the glass-containing encapsulant to thoroughly wet the glass substrate. To increase the softening and fluidity of the glass-containing encapsulant, one can either raise the bonding temperature to lower the viscosity of the glass, or reduce the amount of filler used to adjust the coefficient of thermal expansion to make it more fluid. However, if the softening viscosity of the glass-containing encapsulant is reduced, residual air bubbles in the encapsulant may expand under vacuum, potentially leading to bubble growth. Also, if the amount of filler is reduced, the difference in the coefficient of thermal expansion between the substrate glass and the encapsulant may increase, potentially making bonding more difficult.

[0012] Alternatively, when joining glass substrates using a glass-containing sealing material, there is a problem in that air bubbles remaining in the sealing material expand due to vacuuming, making them more prone to growth.

[0013] One embodiment of the present disclosure aims to provide a sealing material that can be sealed at a low temperature of 400°C or below and that can suppress foaming, as well as a multilayer glass panel formed using this sealing material. Another embodiment of the present disclosure aims to provide a sealing material that can be sealed at a low temperature of 400°C or below and that can improve softening and fluidity, as well as a multilayer glass panel formed using this sealing material.

[0014] The following embodiments are specific means for solving the above problems: <1> A sealing material comprising lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide, and low thermal expansion filler particles with a lower coefficient of thermal expansion than the lead-free low-melting-point glass particles, wherein the low thermal expansion filler particles include fine filler particles with an average particle diameter of less than 3 μm. <2> A sealing material comprising lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide, and low thermal expansion filler particles with a lower coefficient of thermal expansion than the lead-free low-melting-point glass particles, wherein the low thermal expansion filler particles include spherical filler particles with an average particle diameter of 10 μm or more. <3> The BET specific surface area of ​​the spherical filler particles is 0.60 m². ２ The sealing material according to <2>, wherein the amount is less than or equal to / g. <4> The sealing material according to <2>, wherein the sphericity of the spherical filler particles is 0.90 to 1. <5> The BET specific surface area of ​​the fine filler particles is 2.0 m².２ The sealing material according to <1>, which is greater than / g. <6> The sealing material according to any one of <1> to <5>, wherein the low thermal expansion filler particles include filler particles having a negative coefficient of thermal expansion. <7> The sealing material according to any one of <1> to <6>, wherein the low thermal expansion filler particles include zirconium tungstate phosphate. <8> The sealing material according to any one of <1> to <7>, which does not include glass beads. <9> The sealing material according to any one of <1> to <8>, which further includes a solvent and a binder resin. <10> A multilayer glass panel comprising: a first glass substrate; a second glass substrate arranged opposite the first glass substrate at a predetermined distance; a spacer sandwiched between the first glass substrate and the second glass substrate to maintain the distance; 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 arranged in the internal space, and the sealing portion containing the sealing material described in any one of <1> to <9>.

[0015] According to one embodiment of the present disclosure, it is possible to provide a sealing material that can be sealed at a low temperature of 400°C or less and that can suppress foaming, as well as a multilayer glass panel formed using this sealing material. According to another embodiment of the present disclosure, it is possible to provide a sealing material that can be sealed at a low temperature of 400°C or less and that can improve softening and fluidity, as well as a multilayer glass panel formed using this sealing material.

[0016] This is a schematic perspective view of the double-glazed glass panel of the present disclosure. This is a cross-sectional view of line A-A in Figure 1A and an enlarged cross-sectional view of the sealing material thereof. This is a schematic perspective view of the configuration during the manufacturing process of the double-glazed glass panel. This is an enlarged cross-sectional view of the peripheral edge of the double-glazed glass panel in Figure 3A. This is a schematic perspective view of the configuration during the manufacturing process of the double-glazed glass panel. This is a cross-sectional view of Figure 4A. This is a schematic cross-sectional view of the configuration during the manufacturing process of the double-glazed glass panel. This is a cross-sectional view of the process following Figure 5A. This is a cross-sectional view of the process following Figure 5B. This is an enlarged cross-sectional view of the area near the sealing material in Figure 6A. This is a cross-sectional view of the process following Figure 6A. This is an enlarged cross-sectional view of the area near the sealing material in Figure 7A. This is a graph showing the temperature profile of the heat treatment in the process of removing the binder resin of the paste-like sealing material. This is a graph showing the temperature profile when heating the sealing material in the process of reducing the internal space of the double-glazed glass panel. This is a DTA curve for a typical glass composition.

[0017] The embodiments for carrying out the present invention will be described in detail below. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including elemental steps, etc.) are not essential unless they are clearly essential in principle, as specifically stated. The same applies to numerical values ​​and their ranges, and do not limit the present invention. In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, as long as the purpose of the process is achieved. In this disclosure, numerical ranges indicated using "~" include the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding substance. If a composition contains multiple substances corresponding to each component, the content or amount of each component means the total content or amount of those multiple substances present in the composition, unless otherwise specified. In this disclosure, each component may contain multiple types of particles. If a composition contains multiple types of particles corresponding to each component, the particle size of each component means the value for a mixture of those multiple particles present in the composition, unless otherwise specified. In this disclosure, the term "layer" includes cases where the layer is formed throughout the entire region when the region in which the layer exists is observed, as well as cases where it is formed only on a part of the region. In this disclosure, "vacuum" means a state of reduced pressure below atmospheric pressure. In this disclosure, "gas capture material" means at least CO2 under vacuum conditions ２ This refers to materials that can capture them.

[0018] (First Embodiment) <Sealing Material> The sealing material according to the first embodiment of the present disclosure comprises lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide, and low thermal expansion filler particles having a lower coefficient of thermal expansion than the lead-free low-melting-point glass particles, wherein the low thermal expansion filler particles include fine filler particles having an average particle diameter of less than 3 μm.

[0019] The sealing material of this disclosure is, for example, a material used in forming vacuum-insulated double-glazed glass panels (also simply referred to as "double-glazed glass panels") applied to building materials such as window glass. For example, the sealing material may be used when forming an internal space between two substrates such as glass substrates via a plurality of spacers, and when hermetically sealing the periphery of the two substrates in order to maintain a vacuum state in the internal space for a long period of time.

[0020] The sealing material of this disclosure contains lead-free low-melting-point glass particles. This is because it does not use lead, which is a prohibited substance under the RoHS (Restriction of Hazardous Substances) Directive and a substance subject to the REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) Regulation. In this disclosure, "low-melting-point glass" means glass with a softening point of 400°C or less. Hereinafter, "low-melting-point glass" may be read as "glass".

[0021] The sealing material according to the first embodiment includes lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide. These lead-free low-melting-point glass particles have a low softening point, enabling hermetic sealing at low temperatures, for example, below 400°C.

[0022] The sealing material according to the first embodiment further contains low thermal expansion filler particles with a lower coefficient of thermal expansion than lead-free low-melting-point glass particles, and the low thermal expansion filler particles include fine filler particles with an average particle diameter of less than 3 μm. By using fine filler particles, foaming can be suppressed. The reason for this is presumed to be as follows. However, the sealing material of this disclosure is not limited to the following presumption. The growth of bubbles in the sealing material is suppressed because the fine filler particles are distributed with high uniformity within the sealing material.

[0023] (Second Embodiment) <Sealing Material> The sealing material according to the second embodiment of the present disclosure comprises lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide, and low thermal expansion filler particles having a lower coefficient of thermal expansion than the lead-free low-melting-point glass particles, wherein the low thermal expansion filler particles include spherical filler particles having an average particle diameter of 10 μm or more.

[0024] The sealing material according to the second embodiment further contains low thermal expansion filler particles, which have a lower coefficient of thermal expansion than the lead-free low-melting-point glass particles, along with the aforementioned lead-free low-melting-point glass particles, and the low thermal expansion filler particles include spherical filler particles with an average particle diameter of 10 μm or more. By using spherical filler particles, it is possible to improve softening and fluidity. The reason for this is presumed to be as follows. Note that the sealing material of this disclosure is not limited to the following presumed reason. Spherical filler particles have a small specific surface area, and the amount of lead-free low-melting-point glass particles that can move in order to flow increases, so softening and fluidity tends to improve.

[0025] The sealing material of the second embodiment exhibits excellent softening and flow properties, enabling bonding at lower temperatures under a given bonding pressure. By increasing softening and flow properties, bonding strength can also be ensured even when bonding at low temperatures. Furthermore, even when the sealing temperature is increased and the viscosity of the sealing material is reduced, bubble growth in the sealed area formed using the sealing material is suppressed. In addition, while it is desirable to perform sealing at low temperatures to suppress foaming, using the aforementioned sealing material makes it possible to suppress foaming even when sealing at higher temperatures, thereby widening the temperature margin during sealing.

[0026] The components included in the sealing material according to the first embodiment of this disclosure and the sealing material according to the second embodiment of this disclosure will be described below. Each of the following components may be applied to the sealing material according to the first embodiment or to the sealing material according to the second embodiment.

[0027] [Lead-free low-melting-point glass particles] The sealing material of this disclosure comprises lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide.

[0028] Furthermore, lead-free low-melting-point glass particles contain silver oxide (Ag). ２It is preferable that the material contains O). Lead-free low-melting-point glass particles containing silver oxide along with vanadium oxide and tellurium oxide have an even lower softening point. Therefore, hermetically sealed at lower temperatures, for example, sealing at temperatures below 320°C is possible. Lowering the sealing temperature has the advantage of shortening the manufacturing cycle and reducing the investment cost of introducing mass production equipment, which is useful for multi-layer glass panels and the like where rapid heating and cooling are difficult, thus enabling cheaper production. On the other hand, in terms of increasing the fluidity of the sealing material, it is preferable to perform sealing at relatively high temperatures, and by using the sealing material of this disclosure, bubble growth can be suppressed even during high-temperature sealing. When manufacturing multi-layer glass panels with a large sealing area, it is preferable to use a sealing material containing spherical filler particles and fine powder filler particles as low thermal expansion filler particles.

[0029] The total content of vanadium oxide and tellurium oxide in the sealing material may be 50 mol% to 80 mol% relative to the total amount of lead-free low-melting-point glass particles. Furthermore, if the lead-free low-melting-point glass particles also contain silver oxide, the total content of vanadium oxide, tellurium oxide, and silver oxide in the sealing material is preferably 70 mol% or more, and more preferably 80 mol% to 98 mol%, relative to the total amount of lead-free low-melting-point glass particles.

[0030] The vanadium oxide content is preferably 15 mol% to 45 mol% relative to the total amount of lead-free low-melting-point glass particles. If the lead-free low-melting-point glass particles contain tellurium oxide, the tellurium oxide content is preferably 15 mol% to 45 mol% relative to the total amount of lead-free low-melting-point glass particles. If the lead-free low-melting-point glass particles contain silver oxide, the silver oxide content is preferably 10 mol% to 50 mol% relative to the total amount of lead-free low-melting-point glass particles. If the lead-free low-melting-point glass particles contain vanadium oxide and tellurium oxide, the tellurium oxide content is preferably 1 to 2 times the molar ratio of vanadium oxide, and if the lead-free low-melting-point glass particles contain vanadium oxide, tellurium oxide, and silver oxide, the silver oxide content is preferably 2 times or less the molar ratio of vanadium oxide.

[0031] Lead-free low-melting-point glass particles are Li ２ O, K ２O, BaO, WO ３ MoO ３ and P ２ O ５ The lead-free low-melting-point glass particles may contain at least one oxide component selected from the group consisting of (hereinafter also referred to as "oxide component 1"). When lead-free low-melting-point glass particles contain oxide component 1, the content of oxide component 1 may be 30 mol% or less, or 20 mol% or less, relative to the total amount of lead-free low-melting-point glass particles.

[0032] Lead-free low-melting-point glass particles are made of Fe ２ O ３ Al ２ O ３ Ga ２ O ３ In ２ O ３ , Y ２ O ３ La ２ O ３ , CEO ２ Er ２ O ３ and Yb ２ O ３ The lead-free low-melting-point glass particles may contain at least one oxide component selected from the group consisting of (hereinafter also referred to as "oxide component 2"). When lead-free low-melting-point glass particles contain oxide component 2, the content of oxide component 2 may be 5 mol% or less, or 0.1 mol% to 3 mol%.

[0033] The content of lead-free low-melting-point glass particles in the sealing material is preferably 40% by volume or more. Furthermore, the lead-free low-melting-point glass particles do not need to maintain an amorphous state after sealing and may crystallize.

[0034] [Low Thermal Expansion Filler Particles] The sealing material of this disclosure contains low thermal expansion filler particles with a lower coefficient of thermal expansion than lead-free low-melting-point glass particles. In the first embodiment, it contains fine filler particles (hereinafter also simply referred to as "fine filler particles") having an average particle diameter of less than 3 μm. In the second embodiment, the low thermal expansion filler particles contain spherical filler particles (hereinafter also simply referred to as "spherical filler particles") having an average particle diameter of 10 μm or more. The sealing material of this disclosure may contain only fine filler particles and spherical filler particles, or it may contain both.

[0035] As low thermal expansion filler particles, those having a negative coefficient of thermal expansion are preferred. By including low thermal expansion filler particles, when manufacturing a double-layered glass panel, the difference in thermal expansion between the first glass substrate, the sealing portion, and the second glass substrate can be reduced, and a sealing portion with higher bonding strength can be obtained. As low thermal expansion filler particles having a negative coefficient of thermal expansion, zirconium tungstate (Zr ２ (WO ４ ) (PO ４ ) ２ ), β-eucryptite (LiAlSiO ４ ) are some examples. Among these low thermal expansion filler particles, zirconium tungstate (Zr ２ (WO ４ ) (PO ４ ) ２ ) is preferred. Zirconium tungstate phosphate has a large negative thermal expansion coefficient of -40 × 10⁻⁶. －７ The temperature is / °C. Furthermore, zirconium tungstate phosphate has good wettability with lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide. From the viewpoint of achieving both airtightness and bonding strength, the content of low thermal expansion filler particles in the sealing material is preferably 10% to 50% by volume.

[0036] The average particle diameter of the spherical filler particles is 10 μm or more, and may be between 12 μm and 30 μm, or between 15 μm and 25 μm. In this disclosure, the average particle diameter of the spherical filler particles can be determined by observing the particles using a scanning electron microscope, calculating the equivalent circle diameter (average of the major and minor axes) for 50 particles with a particle diameter of 5 μm or more, and taking the arithmetic mean of these values.

[0037] The average particle size of the fine filler particles is less than 3 μm, and may be between 0.1 μm and 2.5 μm, or between 0.5 μm and 2.0 μm. In this disclosure, the average particle size of the fine filler particles can be determined by observing the particles using a scanning electron microscope, calculating the equivalent circle diameter (average of the major and minor axes) for 50 particles with a particle size of less than 5 μm, and taking the arithmetic mean of these values.

[0038] The spherical filler particles and fine filler particles contained in the low thermal expansion filler particles may be filler particles of the same material or filler particles of different materials.

[0039] The BET specific surface area of ​​spherical filler particles is 0.60 m². ２ It may be less than or equal to / g, and 0.50m ２ It may be less than or equal to / g, and 0.40m ２ The amount may be less than or equal to / g. The lower limit of the BET specific surface area of ​​the spherical filler particles is not particularly limited, for example, 0.10 m². ２ It may be greater than or equal to / g. In this disclosure, the BET specific surface area can be determined using the BET method from the adsorption isotherm obtained from nitrogen adsorption measurements at 77K.

[0040] The sphericity of the spherical filler particles may be between 0.90 and 1, or between 0.92 and 0.99. In this disclosure, sphericity means [(diameter of a circle equal to the projected area of ​​the particle) / (diameter of the smallest circle circumscribing the projected image of the particle)]. For example, sphericity is calculated by observing an image magnified 1000 times with a scanning electron microscope, selecting 10 particles arbitrarily, measuring the sphericity of each particle using the method described above, and taking the arithmetic mean value. Note that sphericity can be determined using commercially available image analysis software.

[0041] The BET specific surface area of ​​the fine filler particles is 1.5 m². ２ It may be 1.8 m or more ２ It may be 2.0 m or more ２ It may be more than / g. There is no particular upper limit to the BET specific surface area of ​​the fine filler particles, for example, 5.0 m². ２ It may be less than / g.

[0042] When the sealing material of this disclosure contains both spherical filler particles and fine filler particles, the volume ratio of spherical filler particles to fine filler particles (spherical filler particles: fine filler particles) is preferably 30:70 to 90:10, more preferably 40:60 to 85:15, even more preferably 50:50 to 80:20, and particularly preferably 60:40 to 75:25.

[0043] Furthermore, the sealing material may contain metal particles or the like in addition to lead-free low-melting-point glass particles and low-thermal-expansion filler particles. The sealing material may also contain a binder resin or a solvent, and may be a paste-like material obtained by mixing these materials with a solvent. Alternatively, this paste-like material may be applied to both sides of a ribbon-shaped foil, dried, and then calcined to produce a material which can be used as the sealing material.

[0044] The binder resin is preferably one or more of ethylcellulose, nitrocellulose, and aliphatic polycarbonate. The solvent is preferably one or more of butylcarbitol acetate, terpene solvents, and propylene carbonate.

[0045] The metal particles are preferably low-melting-point metals with a melting point of 300°C or lower. Examples of low-melting-point metals include tin and tin-based alloys. Examples of tin-based alloys include alloys containing at least one selected from the group consisting of silver, copper, zinc, and antimony. When the sealing material contains metal particles, the metal particle content in the sealing material is preferably 10% to 70% by volume from the viewpoint of thermal insulation and bonding strength.

[0046] The sealing material may or may not contain glass beads. If the sealing material contains glass beads, the volume content of glass beads in the solid content may be 10% or more and 35% or less, less than 10%, or 5% or less.

[0047] The glass beads are preferably made of the same or similar glass material as the first and second glass substrates. This is because having the same or similar thermal expansion characteristics makes it possible to stably improve the mechanical strength of the sealing portion. Specifically, glass beads such as soda-lime glass, borosilicate glass, and quartz glass are preferred.

[0048] In this disclosure, "glass beads" are defined as substantially spherical glass. In addition, in a multilayer glass panel, low thermal expansion filler particles 9 are introduced to match the thermal expansion of the glass-containing sealing material 4 with the thermal expansion of the first glass substrate 1 and the second glass substrate 2.

[0049] <Multilayer Glass Panel> The multilayer glass panel of the present disclosure comprises a first glass substrate, a second glass substrate arranged opposite the first glass substrate at a predetermined distance, a spacer sandwiched between the first glass substrate and the second glass substrate to maintain the distance, 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 arranged in the internal space, and the sealing portion including a sealing material according to the first embodiment of the present disclosure or a sealing material according to the second embodiment of the present disclosure.

[0050] (First glass substrate and second glass substrate) The multilayer glass panel of the present disclosure comprises a first glass substrate and a second glass substrate arranged to face the first glass substrate at a predetermined distance apart. The first glass substrate and the second glass substrate are arranged to face each other at a predetermined distance apart by inserting a spacer between them.

[0051] Examples of the first and second glass substrates include float glass, patterned glass, frosted glass, tempered glass, wired glass, and re-wound glass, each independently. The first and second glass substrates may be made of the same material or different materials. These glasses may be air-cooled or chemically strengthened. By using tempered glass that has been air-cooled or chemically strengthened, for example, the number of spacers provided between the pair of substrates can be reduced. When spacers made of a material with high thermal conductivity are used, reducing the number of spacers improves heat insulation. As the first and second glass substrates, soda-lime glass is preferred because it is inexpensive. For example, glass with a thermal expansion coefficient of (80-90) × 10 －７ Soda-lime glass substrates in the temperature range of / °C are commonly used.

[0052] (Spacer) The multilayer glass panel of this disclosure includes a spacer that is sandwiched between a first glass substrate and a second glass substrate to maintain the gap between them. The spacer is located in the internal space enclosed by the first glass substrate, the second glass substrate, and the sealing portion. The material of the spacer is not particularly limited as long as it has lower hardness than the pair of first and second glass substrates and has appropriate compressive strength. Examples include glass, metal, alloy, steel, ceramics, and plastic. From the viewpoint of the heat insulation properties of the vacuum insulation member, it is preferable to use a material with low thermal conductivity. Specific resins include polyimide resin, polyamide resin, fluororesin, epoxy resin, phenoxy resin, and silicone resin.

[0053] The shape of the spacer is not particularly limited and can be cylindrical, spherical, linear, or mesh-shaped, for example. The size of the spacer can be selected according to the area of ​​the first and second glass substrates, the distance between the surfaces of the first and second glass substrates, etc.

[0054] (Sealing portion) The multilayer glass panel of this disclosure includes a sealing portion sandwiched between a first glass substrate and a second glass substrate. The sealing portion is preferably provided on the peripheral edges of the first glass substrate and the second glass substrate, thereby suitably forming an internal space surrounded by the first glass substrate, the second glass substrate and the sealing portion.

[0055] For example, the sealing portion is formed by applying the aforementioned sealing material to at least one of the first glass substrate and the second glass substrate, stacking the first glass substrate and the second glass substrate with the applied sealing material in between, and then heating the sealing material to a temperature near or above its softening point to hermetically seal the gap.

[0056] The multilayer glass panel of this disclosure may include components other than the first glass substrate, the second glass substrate, the spacer, and the sealing portion.

[0057] (Gas trapping material) For example, a gas trapping material may be placed in the internal space. Due to thermal decomposition of binder resin that may be contained in the sealing part, long-term use of the double-layered glass panel, etc., gas may be released from the sealing material that seals the glass substrate and the opposing glass substrate. This may reduce the vacuum level in the internal space and reduce the thermal insulation performance. By installing a gas trapping material in the internal space, the released gas is trapped, and thermal insulation performance can be suitably maintained.

[0058] Specific examples of the multi-layer glass panel and its manufacturing method described herein will be explained below with reference to the drawings, but the present invention is not limited thereto. Furthermore, the sizes of the components in each figure are conceptual, and the relative relationships of the sizes of the components are not limited thereto.

[0059] Figure 1 is a schematic perspective view of the multilayer glass panel of the present disclosure, and Figure 2 is a cross-sectional view taken along line A-A in Figure 1 and an enlarged cross-sectional view of the sealing portion thereof. As shown in Figures 1 and 2, the multilayer glass panel 100 comprises a first glass substrate 1, a second glass substrate 2 arranged opposite the first glass substrate 1 with a space between them, a sealing portion 4 provided on the periphery of the internal space 5 formed between the first glass substrate 1 and the second glass substrate 2, and a gas trapping material 7 arranged in the internal space 5. The internal space 5 formed by the first glass substrate 1, the second glass substrate 2 and the sealing portion 4 is in a vacuum state.

[0060] A heat-reflective film 6 having a heat-shielding function is arranged on the surface of the second glass substrate 2 facing the internal space 5. The heat-reflective film 6 is useful when the double-glazed glass panel 100 is applied to window glass for building materials. Also, as shown in the enlarged view of Figure 2, the sealing portion 4 includes low-melting-point glass 8 and low-thermal-expansion filler particles 9. Examples of low-thermal-expansion filler particles 9 include fine filler particles with an average particle diameter of less than 3 μm, or spherical filler particles with an average particle diameter of 10 μm or more. The low-thermal-expansion filler particles 9 are dispersed in the low-melting-point glass 8.

[0061] Next, the manufacturing method of the multi-layer glass panel of this disclosure will be described. The following description will explain an example of vacuum sealing of the glass substrate using the so-called "exhaust pipe method".

[0062] Figure 3A is a schematic perspective view of the configuration during the manufacturing process of a double-glazed glass panel, and Figure 3B is an enlarged cross-sectional view of the peripheral edge of the double-glazed glass panel shown in Figure 3A. First, as shown in Figure 3A, a paste-like sealing material 16 is applied to the peripheral edge of the first glass substrate 1, which is provided with exhaust holes 13 and exhaust pipes 14, using a dispenser 15. Then, the applied sealing material is dried on a hot plate at approximately 150°C for 30 minutes to evaporate and remove the solvent from the paste-like sealing material 16.

[0063] Figure 8A is a graph showing the temperature profile of the heat treatment in the process of removing the binder resin from the paste-like sealing material. After the process shown in Figure 3A, the binder resin contained in the paste-like sealing material 16 is decomposed and removed according to the temperature profile shown in Figure 8A. Subsequently, the sealing material 17 is formed on the first glass substrate 1 by firing to soften and flow the low-melting-point glass 8 particles contained in the paste-like sealing material 16.

[0064] The firing conditions are as shown in Figure 8A, with heating and cooling rates of 2°C / min in air. During the heating process, the refractory point M of the low-melting-point glass 8 is... ｇ and softening point T ｓ A constant temperature T between １ The binder resin is then broken down and removed by holding it for about 30 minutes. After that, the temperature is raised again until the softening point T is reached. ｓ A constant temperature T that is 20°C to 40°C higher ２ By holding it in place for about 30 minutes, the sealing material 17 is formed on the peripheral edge of the first glass substrate 1.

[0065] Here, we will explain the characteristic temperature of low-melting-point glass. Figure 9 shows the DTA (Differential Thermal Analysis) curve of a typical glass composition. Generally, the DTA of glass is calculated using glass particles with a particle size of several tens of micrometers, and high-purity alumina (α-Al) is used as a standard sample. ２ O ３ The measurement is performed using particles at a heating rate of 5°C / min in air. As shown in Figure 9, the transition point T is defined as the starting temperature of the first endothermic peak or the temperature at which the glass transitions to a supercooled liquid. ｇ The point at which the endothermic peak temperature or the point at which the expansion of the glass stops is called the bending point M. ｇ The second endothermic peak temperature or the temperature at which softening begins is called the softening point T. ｓ The temperature at which glass becomes a sintered body is called the sintering point T. ｓｉｎｔ The pour point T is the temperature at which glass begins to melt. ｆ , the working point T is set to a temperature suitable for molding molten glass. ｗ The starting temperature of the exothermic peak due to crystallization is the crystallization start temperature T. ｃｒｙ The characteristic temperatures for each temperature are determined by the tangent method.

[0066] Also, T ｇ , M ｇ and T ｓ and other characteristic temperatures are defined by the viscosity of the glass. T ｇ is 10 １３．３ poise, M ｇ is 10 １１．０ poise, T ｓ is 10 ７．６５ poise, T ｓｉｎｔ is 10 ６ poise, T ｆ is 10 ５ poise, T ｗ is 10 ４ poise, which is the temperature corresponding to.

[0067] Through the above process, the paste-like sealing material 16 changes into the sealing material 17.

[0068] FIG. 4A is a schematic perspective view of the structure during the manufacturing process of the multilayer glass panel. FIG. 4B is a cross-sectional view of FIG. 4A. As shown in FIGS. 4A and 4B, a heat ray reflecting film 6 is formed on the entire single surface of the second glass substrate 2 by vapor deposition. Then, a large number of spacers 3 are provided on the surface of the heat ray reflecting film 6.

[0069] FIG. 5A is a schematic cross-sectional view of the structure during the manufacturing process of the multilayer glass panel, and FIG. 5B is a cross-sectional view of the process following FIG. 5A. As shown in FIG. 5A, the first glass substrate 1 and the second glass substrate 2 manufactured in the above process are aligned so as to face each other. Then, as shown in FIG. 5B, they are fixed with a heat-resistant clip 18 or the like. This is installed inside the vacuum evacuation furnace 19 as shown in FIG. 6A, an electric heater 20 is attached to the exhaust pipe 14, and the exhaust pipe 14 is connected to a vacuum pump 21.

[0070] FIG. 6A is a cross-sectional view of the process following FIG. 5B, and FIG. 6B is an enlarged cross-sectional view near the sealing material of FIG. 6A. FIG. 8B is a graph showing the temperature profile when heating the sealing material in the process of reducing the pressure in the internal space of the multilayer glass panel. As shown in FIG. 8B, first, at atmospheric pressure, the yield point M ｇ and the softening point T ｓ of the low melting point glass 8 contained in the sealing material 17, and a constant temperature T ３Heat to the softening point T and hold for about 30 minutes. Then, while exhausting the internal space 5 through the exhaust holes 13 and exhaust pipe 14 shown in Figures 6A and 6B, ｓ A temperature 10°C to 30°C higher T ４ Heat until the temperature is reached. This forms a sealing portion 4 on the periphery with the sealing material 17 and creates a vacuum in the internal space 5.

[0071] Figure 7A is a cross-sectional view of the process following Figure 6A, and Figure 7B is an enlarged cross-sectional view of the area near the sealing material in Figure 7A. As shown in Figures 7A and 7B, the exhaust pipe 14 is burned off by the electric heater 20 during or after cooling, thereby maintaining the vacuum state in the internal space 5. In this manner, the double-glazed glass panel is manufactured.

[0072] The above disclosure will be described in more detail below based on examples, but the above disclosure is not limited to the following examples.

[0073] <Examples 1-11> [Preparation of sealing material] A paste-like sealing material was prepared using lead-free low-melting-point glass particles, low-thermal-expansion filler particles, a binder resin, and a solvent. Table 1 shows the proportion of lead-free low-melting-point glass particles in the lead-free low-melting-point glass particles and low-thermal-expansion filler particles. Details of each component are as follows: (Lead-free low-melting-point glass particles) Vanadium oxide (V) ２ O ５ Glass particles (T) containing ｇ = 255℃, M ｇ (=270°C) (Low thermal expansion filler particles) Average particle diameter 19 μm, BET specific surface area 0.3 m² ２ Spherical filler particles (material: zirconium tungstate phosphate) with a density of / g, and an average particle diameter of 1.4 μm and a BET specific surface area of ​​2.3 m². ２ The mixture with fine filler particles (material: zirconium tungstate phosphate) at a concentration of / g, and the mixing ratio are as shown in Table 1. (Binder resin) Aliphatic polycarbonate (Solvent) Propylene carbonate

[0074] <Reference Example 1> [Preparation of Sealing Material] The sealing material was prepared in the same manner as in the example, except that the crushed filler particles shown below were used as the low thermal expansion filler particles. (Crushed Filler Particles) Average particle diameter of 15 μm, BET specific surface area of ​​0.8 m² ２ Crushed filler particles (material: zirconium tungstate phosphate) at a concentration of / g

[0075] The softening fluidity, bonding strength, and foaming properties of the prepared sealing material were evaluated as follows. The results are shown in Table 1.

[0076] [Softening Flowability] Softening flowability was evaluated by performing a button flow test. Specifically, lead-free low-melting-point glass particles and low-thermal-expansion filler particles were mixed in the ratios shown in Table 1. 1 g of the mixture was weighed out and a compacted body was prepared using a 10 mmφ die. The compacted body was placed on soda-lime glass and heated at 360°C for 20 minutes. Softening flowability was evaluated by the diameter (mm) after these treatments. The evaluation criteria for softening flowability are as follows: -Evaluation Criteria- A: Softening flowability is greater than that of Reference Example 1. B: Softening flowability is about the same as that of Reference Example 1. C: Softening flowability is lower than that of Reference Example 1. D: No softening flow.

[0077] [Bonding Strength] Two 20mm x 50mm x 3mm blue glass plates were used as substrates for bonding the sealing material. On one substrate, an amount of sealing material was applied such that the diameter of the frit after bonding would be approximately 14mm and the thickness approximately 200μm, and the solvent was heated and dried. Then, the other substrate was placed on top in a cross shape, and the bond was obtained by heating at 350°C for 20 minutes to obtain a bond strength test specimen. With the upper substrate supported from below at two points near the cross intersection, a load was applied from above to two points near the cross intersection of the lower substrate to break the bond. The bond strength (MPa) was calculated from the strength at break (N) and the bond diameter (mm), and the bond strength was evaluated. The evaluation criteria for bond strength are as follows: -Evaluation Criteria- A: Bond strength is greater than that of Reference Example 1. B: Bond strength is about the same as that of Reference Example 1. C: Bond strength is lower than that of Reference Example 1.

[0078] [Foaming] The degree of foaming of the sealing material was evaluated by performing a vacuum foaming test according to the following procedure. The sealing material was applied to a glass substrate, the solvent was heated and dried, and a spacer was placed. Then, the bonding-side glass substrate with a vacuum exhaust hole was placed on top, and vacuum evacuation was performed while heating at 350°C for 20 minutes. After cooling to room temperature, the vacuum evacuation was stopped to obtain an observation laminate. The observation laminate was observed by shining transmitted light on it, and the foaming of the sealing material was evaluated according to the following criteria. -Evaluation Criteria- A: The number of bubbles with a diameter of 100 μm or more in the region within 1 mm and 10 mm in length from the vacuum-side edge of the sealing material is 3 or less. B: The number of bubbles with a diameter of 100 μm or more in the region within 1 mm and 10 mm in length from the vacuum-side edge of the sealing material is 4 to 10. C: The number of bubbles with a diameter of 100 μm or more in the region within 1 mm and 10 mm in length from the vacuum-side edge of the sealing material is 11 or more.

[0079]

[0080] In each example using spherical fillers, a level of softening and fluidity equivalent to or better than that of Reference Example 1 was achieved, and it was possible to further improve softening and fluidity by increasing the amount of spherical fillers. In each example using fine powder fillers, a level of foam suppression equivalent to or better than that of Reference Example 1 was achieved, and foam suppression could be more effectively achieved by increasing the amount of fine powder fillers. Furthermore, in each example, it was confirmed that bonding strength with glass could be ensured at temperatures below 400°C, and that sealing was possible at low temperatures below 400°C.

[0081] The disclosure of Japanese Patent Application No. 2024-160351 is incorporated in its entirety by reference. All documents, patent applications, and technical standards in this disclosure are incorporated by reference to the same extent as if each individual document, patent application, and technical standard had been specifically and individually noted as being incorporated by reference.

[0082] 1...First glass substrate, 2...Second glass substrate, 3...Spacer, 4...Sealing part, 5...Internal space, 6...Heat ray reflective film, 7...Gas capture material, 8...Low melting point glass, 9...Low thermal expansion filler particles, 13...Exhaust hole, 14...Exhaust pipe, 15...Dispenser, 16...Paste-like sealing material, 17...Sealing material, 18...Heat-resistant clip, 19...Vacuum exhaust furnace, 20...Electric heater, 21...Vacuum pump, 100...Double-glazed glass panel

Claims

1. A sealing material comprising lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide, and low thermal expansion filler particles having a lower coefficient of thermal expansion than the lead-free low-melting-point glass particles, wherein the low thermal expansion filler particles include fine powder filler particles with an average particle diameter of less than 3 μm.

2. A sealing material comprising lead-free low-melting-point glass particles containing vanadium oxide and tellurium oxide, and low thermal expansion filler particles having a lower coefficient of thermal expansion than the lead-free low-melting-point glass particles, wherein the low thermal expansion filler particles include spherical filler particles having an average particle diameter of 10 μm or more.

3. The BET specific surface area of ​​the spherical filler particles is 0.60 m². ２ The sealing material according to claim 2, wherein the amount is less than or equal to / g.

4. The sealing material according to claim 2, wherein the sphericity of the spherical filler particles is 0.90 to 1.

5. The BET specific surface area of ​​the fine filler particles is 2.0 m². ２ The sealing material according to claim 1, which is greater than / g.

6. The sealing material according to claim 1 or claim 2, wherein the low thermal expansion filler particles include filler particles having a negative coefficient of thermal expansion.

7. The sealing material according to claim 1 or claim 2, wherein the low thermal expansion filler particles include zirconium tungstate phosphate.

8. The sealing material according to claim 1, which does not contain glass beads.

9. The sealing material according to any one of claims 1 to 5 and 8, further comprising a solvent and a binder resin.

10. A multilayer glass panel comprising: a first glass substrate; a second glass substrate disposed opposite the first glass substrate at a predetermined distance; a spacer sandwiched between the first glass substrate and the second glass substrate to maintain the distance; 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, and the sealing portion containing the sealing material described in any one of claims 1 to 5 and claim 8.

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