JP2009286685A - Double-glazed glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide double-glazed glass which has such a laminated structure that a flat plate-like transparent porous body is held between two glass sheets in which the improvement of both of heat insulating property and visible light transmissivity required for double-glazed glass is expected and which has enhanced fracture resistance to deformation by external pressure. <P>SOLUTION: The transparent porous body 3 has a compression limit strain larger than the tensile limit strain, and a compression strain is previously imparted to the transparent porous body 3. Specifically, a first compression strain is previously imparted to the transparent porous body 3 in a thickness direction by pressure added to the transparent porous body 3 in the thickness direction from the two glass sheets 2, and the transparent porous body 3 is held by the two glass sheets 2 in a state that expansion of the transparent porous body 3 in a direction parallel to the surface of the glass sheet 2 is suppressed. Thereby, a second compression strain is previously imparted to the transparent porous body 3 in the direction parallel to the surface of the glass sheet 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multilayer glass, and more particularly to a multilayer glass having a laminated structure in which a flat transparent porous body that transmits visible light is sandwiched between two sheet glasses.

When the walls, floors, ceilings, etc. of buildings such as houses and buildings are highly insulated, rock wool with a thickness of about 100 to 200 mm is applied to the walls, ceilings, etc. It has a heat insulation performance of about 0.2 to 0.5 W / (m ² · K). On the other hand, even if the glass part of the window is a high-performance multi-layer insulation glass (typical air layer thickness 60 mm), the thermal conductivity is 1.6 to 3.0 W / (m ² · K), which is about one digit. Because it is so large, more than half of the heat that goes in and out, except for ventilation, passes through the glass part of the window. Therefore, increasing the heat shielding property of the glass part is very important for achieving high heat insulation and energy saving.

  In general, the double-layer heat insulating glass forms a sealed air layer in a range in which air convection hardly occurs between two sheet glasses to form a heat insulating layer. In order to increase the thermal insulation of the multilayer insulation glass, there is a multilayer insulation glass in which a sealed air layer is filled with argon gas having a lower thermal conductivity than air or a vacuum multilayer glass in which the sealed air layer is evacuated (for example, , See Patent Documents 1 to 3 below). In addition, since it is difficult to produce a large-area double-layer insulation glass because it is necessary to ensure the airtightness of the sealed air layer by sealing with argon gas or evacuating, sealing is performed for the purpose of reducing the amount of air in the sealed air layer. There is a multilayer heat insulating glass in which an aerosol in which silica fine particles are connected in a chain shape is enclosed in an air layer to achieve high heat insulation (for example, see Patent Document 4 below). In addition, there is a multi-layer glass in which a transparent porous heat insulating layer such as silica airgel is provided in a hollow layer between two plate glasses (see, for example, Patent Document 5 below).

JP 11-199277 A Japanese Patent Laid-Open No. 11-092181 Japanese Patent Application Laid-Open No. 11-079795 Japanese Patent Laid-Open No. 11-071141 JP 2006-282465 A International Publication No. 2005/110919 Pamphlet Kazuyoshi Kanamori, et al. "New Transparent Methylsilsesquioxane Aerogels and Xerogels with Improved Mechanical Properties", Advanced Metals, 2007, 19, p. 1589-1593 “Physical Properties: Silica Aerogels”, [online], Lawrence Berkeley National Laboratory, [Search April 4, 2008], Internet <URL: http://eande.lbl.gov/ECS/aerogels/sa-physicals/sa-physicals html>

  However, the conventional vacuum double-glazed glass has a complicated structure in which many supporting members are inserted between the two glass sheets to support the atmospheric pressure applied to the sealed air layer from the outside between the two glass sheets. Weight increase is inevitable because the structure of the part needs to be robust.

  In addition, in multi-layer insulation glass in which aerosol is sealed in a sealed air layer, many voids larger than the particle size remain between the particles, and air convection is not effectively suppressed. Although it can be achieved, a dramatic improvement in thermal insulation performance cannot be expected. Moreover, since incident light is scattered by the space | gap which exists between particle | grains, there exists a problem that the visible light transmittance | permeability of a heat insulation layer falls.

  In addition, in the case of double-layer glass in which a transparent porous heat insulating layer such as silica aerogel is provided in the hollow layer between two plate glasses, in order to ensure the visible light transmittance of the transparent porous heat insulating layer, the refractive index change Since the scattering suddenly increases when the period of the light becomes about 1/5 to 1/10 of the wavelength of the light, the central pore diameter is several nm to 100 nm, and there are no through holes, gaps, or joints having a larger pore diameter than the pores. A flat porous body is desirable. Whether the transparent porous heat insulation layer of the multilayer glass disclosed in Patent Document 5 is a flat porous body is not clear from the disclosure. In addition, if there are many gaps and joints in the flat porous body, light is irregularly reflected at the portions, so that the transparency is impaired and the gaps and joints can be easily visually observed, which causes a problem in appearance. Therefore, by using a flat transparent porous body with only pores, both the heat insulating properties and the visible light transmittance required for the multi-layer glass compared to the multi-layer heat insulating glass in which the aerosol is sealed in the sealed air layer. Expected to improve performance.

  Here, as a general property of ceramics and glass materials, there is a problem that the tensile limit strain is extremely small compared to the compression limit strain. The reason why these materials are easily broken by tensile strain is that when tensile stress is applied, stress concentrates on small scratches (initial cracks) on the surface, and the stress concentration factor increases with the progress of cracks, resulting in rapid failure. This is thought to be due to progress. On the other hand, since the stress concentration mechanism does not work in the case of compressive strain, there is no problem that it is easily broken by the compressive strain. Therefore, since a transparent porous body such as silica airgel is a kind of ceramics or glass material, it has a characteristic that it is easily broken by tensile strain. For this reason, when a transparent porous body such as silica airgel is used for a double-glazed glass, when the glass surface is curved by an external pressure such as strong wind, the transparent porous body is also curved in the same manner as the glass surface, and along the curved surface. Tensile strain occurs. A transparent porous body such as silica airgel easily cracks due to tensile strain exceeding the tensile limit strain, and light is irregularly reflected on the crack surface, so that visible light transmission and transparency are impaired. Therefore, if a transparent porous body such as silica airgel can be easily broken against a tensile stress, a multilayer glass having high heat insulation and visible light transmission can be provided.

  The present invention has been made in view of the above-mentioned problems, and the object thereof is between two sheet glasses that are expected to improve both the heat insulating properties and the visible light transmission performance required for a double-layer glass. An object of the present invention is to provide a double-glazed glass having a laminated structure in which a flat transparent porous body is sandwiched, and having enhanced fracture resistance against deformation caused by external pressure.

  The multilayer glass according to the present invention for achieving the above object is a multilayer glass having a laminated structure in which a flat transparent porous body that transmits visible light is sandwiched between two sheet glasses, The first feature is that the porous body has a compression limit strain larger than the tensile limit strain, and a compressive strain is applied to the transparent porous body in advance.

  According to the multilayer glass of the first feature, since the compression limit strain of the transparent porous body is large, even if the compression strain due to the deformation is added to the compression strain applied in advance due to the deformation due to the external pressure, the compression limit strain is generated. The transparent porous body is not destroyed by the synthetic compression strain as long as it is below. On the other hand, the tensile limit strain of the transparent porous material is smaller than the compression limit strain. However, in the composite strain in which the tensile strain generated by the preliminarily applied compressive strain and deformation is offset, the tensile strain is greatly reduced or the compression strain is reduced. Therefore, it is possible to prevent the transparent porous body from being destroyed by the tensile strain generated by the deformation by adjusting the compression strain to be applied in advance and setting the synthetic strain to be equal to or lower than the tensile limit strain. It becomes possible.

  As a result of the above, as with ceramics and glass materials, it has the property of being easily broken by tensile strain, but silica aerogel, methylated silica xerogel, etc. that exhibit excellent properties in both visible light transmission and thermal insulation properties It becomes possible to use an inorganic or organic-inorganic hybrid amorphous gel or other transparent porous material having similar characteristics as a transparent porous material of a multi-layer glass, mechanical strength characteristics, visible light permeability, and A multilayer glass excellent in heat insulation can be provided.

  In this specification, compression strain, tensile strain, compression limit strain, and tensile limit strain are defined and used as follows. The compressive strain is represented by a ratio (ΔL / L) obtained by dividing the change in length (ΔL) due to compression in the direction of compressive stress by the length (L) of the object before compression, and the tensile strain is the direction of tensile stress. Is expressed by a ratio (ΔL / L) obtained by dividing the change in length (ΔL) due to pulling by the length (L) of the object before pulling. The compressive strain is equivalent to a negative tensile strain, and the compressive strain and the tensile strain have a relationship in which signs are reversed. The compression limit strain is a limit compression strain that causes an object to break, and the tensile limit strain is a limit strain that causes an object to break.

  Further, the multilayer glass having the first characteristic has a compressive strain that is greater than or equal to a maximum tensile strain predicted to be generated in the transparent porous body due to deformation caused by an external pressure applied to the two plate glasses. A second feature is that a compressive strain is applied in advance to the transparent porous body so as to be applied in the direction of strain.

  According to the multilayer glass of the second feature, the compressive strain applied in advance in the direction of the tensile strain that is predicted to be generated in the transparent porous body by deformation due to external pressure is equal to or greater than the predicted maximum value of the tensile strain. Even if a tensile strain within the maximum position occurs, it is avoided that the tensile strain is generated in the direction of the tensile strain. Therefore, the tensile strain generated by the deformation is no matter how small the tensile limit strain of the transparent porous body is. This makes it possible to prevent the transparent porous body from being destroyed.

  Furthermore, the multi-layer glass of the first or second feature is the above-mentioned transparent porous body with respect to the transparent porous body by pressure applied in the thickness direction of the transparent porous body from the two plate glasses to the transparent porous body. In a state in which the first compressive strain is applied in the thickness direction in advance and the transparent porous body is prevented from expanding in a direction parallel to the surfaces of the two sheet glasses, the transparent porous body is the two sheet glasses. As a third feature, the second compressive strain is preliminarily applied to the transparent porous body in a direction parallel to the surfaces of the two sheet glasses.

  According to the multilayer glass of the third feature, the first compressive strain in the thickness direction with respect to the transparent porous body by the pressure applied in the thickness direction of the transparent porous body, the direction parallel to the surfaces of the two plate glasses The second compression strain can be applied in advance. That is, the transparent porous body is preliminarily imparted with compressive strain in all directions. When a strong pressure such as strong wind is applied from one outer surface of the two glass sheets of the multilayer glass, the two glass sheets are deformed to bend toward the other side. Due to this deformation, the same curvature is generated in the transparent porous body, and tensile strain is generated in the direction parallel to the surfaces of the two glass sheets along the curved surface. Therefore, since the compressive strain previously applied in the direction parallel to the surfaces of the two glass sheets cancels out the tensile strain generated along the curved surface, the fracture resistance due to the tensile strain is improved. In addition, since the compressive strain is preliminarily applied to the transparent porous body in all directions, the fracture resistance is also improved in the same manner as described above against tensile strain generated in a direction other than the direction parallel to the surfaces of the two sheet glasses. Will be.

  Furthermore, the multilayer glass of the third feature is obtained by tightening the two plate glasses in the thickness direction of the transparent porous body by a window frame sandwiching the two plate glasses in the thickness direction of the transparent porous body. Alternatively, by reducing the gas phase in the transparent porous body, the first compressive strain is preliminarily applied to the transparent porous body by the atmospheric pressure applied from both sides of the two plate glasses, and the transparent porous body A fourth feature is that the second compressive strain is preliminarily applied to the transparent porous body by preventing the body from expanding in a direction parallel to the surfaces of the two plate glasses. To do.

  According to the multilayer glass of the fourth feature, the first and second compressive strains can be specifically applied to the transparent porous body in advance, so that the action of the multilayer glass of the third feature is performed. An effect can be produced reliably.

  Further, the multilayer glass having the third or fourth feature has a compression limit strain inherent to the transparent porous body of greater than 3.5%, the first compression strain of 3.5% or more, and the transparent porous glass. The fifth feature is that the compression strain is less than the compression limit inherent in the body.

  According to the multilayer glass of the fifth feature, for example, assuming use of methylated silica xerogel or silica airgel as the transparent porous body, the Poisson's ratio as a material of these transparent porous bodies is about 0.2. Therefore, the second compression strain is 0.7% or more and less than 0.2 times the compression limit strain in the direction parallel to the surfaces of the two sheet glasses. Since the limit deformation of window glass for buildings is designed to have a radius of curvature of about 5 m, it is assumed that the maximum dimension of the plate glass is 2 m, and the distance between both ends of the maximum dimension of the plate glass is restricted to a length of 2 m. When the limit deformation curve occurs, the 2 m long plate glass stretches to about 2.0136 m, and a tensile strain of about 0.68% occurs. Here, in the case where the plate glass and the transparent porous body are brought into contact with each other with frictional force, and the two are completely in contact with each other and do not move relatively, the plate glass is oriented in a direction parallel to the glass surface with respect to the transparent porous plate. As with the case, a tensile strain of about 0.68% is generated. Accordingly, the tensile strain within the above assumption is offset by the second compressive strain and does not appear as tensile strain, so that the transparent porous body is prevented from being broken due to cracks or the like exceeding the tensile limit strain.

  On the other hand, when the plate glass and the transparent porous body are not in contact with each other with frictional force, the strain generated in the transparent porous body due to the limit deformation curve of the window glass for buildings is generated only due to the curvature of the transparent porous body. For this reason, tensile strain occurs on the convex side of the curved surface, and compressive strain occurs on the concave side. When the thickness of the transparent porous body is about 10 mm, the maximum tensile strain generated in the direction parallel to the surfaces of the two plate glasses is about 0.1% with respect to the curvature having a curvature radius of 5 m. Therefore, since the tensile strain is greatly relieved compared with the case where the plate glass and the transparent porous body are brought into contact with each other with a frictional force, the tensile strain within the above assumption is offset by the second compression strain and does not appear as a tensile strain. Further, it is possible to prevent the transparent porous body from cracking and breaking beyond the tensile limit strain.

  Furthermore, the multilayer glass having any one of the above characteristics is characterized in that the transparent porous body is an inorganic or organic-inorganic hybrid amorphous gel. In the multi-layer glass having the sixth feature, it is particularly preferable that the transparent porous body contains silicon and oxygen in a skeleton structure, and further, the transparent porous body is a methylated silica xerogel. preferable.

  According to the double-glazed glass of the sixth feature, a flat transparent porous body having visible light permeability and heat insulation can be realized. By applying a compressive strain in advance using the transparent porous body, In addition, it is possible to realize a multi-layer glass having both visible light transparency, transparency, and heat insulation properties, which have enhanced fracture resistance against deformation caused by external pressure. In particular, methylated silica xerogel is a homogeneous transparent porous body having only pores with a central pore diameter of several nanometers to about 60 nm, and is ideal as an intermediate layer of a multilayer glass having both visible light permeability and heat insulation properties. Material. For example, a methylated xerogel with a thickness of 10 mm, which has been produced with great care, has a visible light transmittance of 80% or more and a haze ratio of 2% or less, sufficient optical properties as a normal double-layer glass for buildings, and a thermal conductivity of 10 mW. It has a low value of less than / mK. In addition, since methylated silica xerogel has been found to be able to realize a very large compression limit strain of 80% or more, the opening area of the multi-layer glass becomes large, and the tensile strength expected to be generated in the transparent porous body by deformation is expected. Even if the maximum value of the strain is further increased, a sufficiently large compression strain that can cope with the maximum value can be applied in advance.

  An embodiment of a multilayer glass according to the present invention will be described with reference to the drawings.

<First Embodiment>
As shown in FIG. 1, the multilayer glass 1 according to the first embodiment of the present invention includes two plate glasses 2, a flat transparent porous body 3 sandwiched between two plate glasses 2, a stopper 4, and The window frame 5 is provided. FIG. 1 is a cross-sectional view showing a schematic structure of the multi-layer glass 1 in a cross section perpendicular to the surfaces of the two plate glasses 2. In the following description, for the sake of easy understanding of the description, the thickness direction of the transparent porous body 3 (that is, the stacking direction of the two plate glasses 2 and the transparent porous body 3) is referred to as the Z direction. The long side direction of the plate glass 2 parallel to the surface and the direction orthogonal to the Z direction is referred to as the X direction, and the short side direction of the plate glass 2 parallel to the surface of the plate glass 2 and the direction orthogonal to both the Z and X directions is the Y direction. Called. Therefore, the cross-sectional view of FIG. 1 shows an XZ cross section parallel to the Z direction and the X direction, or a YZ cross section parallel to the Z direction and the Y direction.

  In the present embodiment, the transparent porous body 3 uses a methylated silica xerogel having only pores having a central pore diameter of about several nm to 60 nm. The methylated silica xerogel has only pores having a central pore diameter of several nanometers to 60 nm, and has a visible light transmittance of 80% or more and a haze ratio of 2% or less at a thickness of about 10 mm. What has sufficient optical characteristics as a layer glass and a low thermal insulation characteristic of 10 mW / mK or less is also obtained. However, the transparent porous body 3 is not limited to the above numerical examples in terms of optical characteristics and heat insulation characteristics, and those having appropriate characteristics can be used depending on the specifications of the multilayer glass 1 as a product.

  Methylated silica xerogel is an organic-inorganic hybrid amorphous gel having a structure in which a methyl group is fixed to a skeleton structure having silicon and oxygen. Xerogel is academically a “gel from which a solvent has been removed” and is defined by a broad concept that does not depend on a drying method for removing the solvent. On the other hand, an airgel is defined as a low density gel using supercritical drying as a drying method. Therefore, in this specification, since the term xerogel is used as a broad concept including aerogel, methylated silica xerogel includes methylated silica aerogel. The methylated silica xerogel including the methylated silica aerogel is produced using, for example, a known production method disclosed in Patent Document 6 or Non-Patent Document 1. Even if a drying method other than supercritical drying such as evaporation drying is used as the drying method used for the methylated silica xerogel, visible light transmittance and mechanical strength characteristics similar to those of the methylated silica airgel are obtained. In this embodiment, these methylated silica xerogels are used. As an example of the mechanical strength characteristics of methylated silica xerogel, FIG. 2 of Non-Patent Document 1 discloses a characteristic curve showing the relationship between compressive stress and compressive strain. A characteristic of about 60% to 80% is assumed. Incidentally, the tensile strength and tensile limit strain of methylated silica xerogel have the disadvantage that they are extremely low like conventional silica airgel and the like.

  As described above, the methylated silica xerogel used in the present embodiment is assumed to be produced using a known production method disclosed in Patent Document 6 or Non-Patent Document 1, Since the porosity (porosity) is assumed to be about 80 to 90%, the Young's modulus is about four orders of magnitude lower than that of high-density silica (for example, plate glass 2) as in the conventional silica airgel and the like. It becomes. As shown in FIG. 2 of Non-Patent Document 1, methylated silica xerogel has a nonlinear compressive stress / compressive strain characteristic, but exhibits a substantially linear characteristic within a range of about 0 to 30% compressive strain. In this case, the Young's modulus is approximately the same as that of a conventional silica airgel or the like. The physical properties of the conventional silica airgel are disclosed in the URL of Non-Patent Document 2 above.

  The vertical and horizontal dimensions and thicknesses of the plate glass 2 and the transparent porous body 3 may be selected appropriately depending on the specifications of the multi-layer glass 1 as a product, similarly to the optical characteristics and the heat insulation characteristics.

  When the transparent porous body 3 is clamped and compressed from both sides by two sheet glasses 2 in the thickness direction (Z direction), the stopper 4 is in a direction parallel to the surface of the sheet glass 2 (X and Y directions). ) To prevent stretching. The material of the stopper 4 is preferably a material having a Young's modulus sufficiently larger than that of the transparent porous body 3 because it is necessary to suppress the expansion of the transparent porous body 3 in the X and Y directions. For example, synthetic resin, glass, wood Metal, etc. can be used.

  The stopper 4 is fixed to the inner side surface 2a on one side of the two sheet glasses 2 at the outer peripheral portion of the end surface facing the X and Y directions of the transparent porous body 3, and the inner side on the other side of the two sheet glasses 2 It protrudes toward the side surface 2b. A concave portion 4 a for interposing a gasket 6 such as an O-ring is formed at the tip of the stopper 4 facing the inner side surface 2 b of the other side glass plate 2, and the inner side surface 2 b of the other side glass plate 2 and the stopper 4 A gasket 6 is provided between the tip portion.

  When the transparent porous body 3 is clamped and compressed from both sides by the two glass sheets 2, if there is no stopper 4, it is directed in the X and Y directions (that is, in all directions parallel to the surface of the glass sheet 2). Although it extends, the stopper 4 prevents the extension. As a result, the transparent porous body 3 is multiplied by the compressive strain SCz due to tightening from the two glass sheets 2 in the Z direction, and the compressive strain SCz in the Z direction is multiplied by the Poisson ratio of the transparent porous body 3 in the X and Y directions. Compression distortion SCxy will occur. That is, compressive stress is generated in the transparent porous body 3 in all directions. Note that the Poisson's ratio of methylated silica xerogel is 0.2 or 0.12 (partial sample) depending on the details of the manufacturing method, referring to the experimental results of Non-Patent Document 1.

The window frame 5 is for fixing the space | interval of the 2 sheet glass 2 of the state which clamped the transparent porous body 3 from both sides, and Z direction outer side surface 2c, 2d of the outer peripheral part of each sheet glass 2 is set to Z direction. The structure is sandwiched. Therefore, in the multilayer glass 1 in the state shown in FIG. 1, the transparent porous body 3 is preliminarily imparted with compressive strain in all directions. The material of the window frame 5 is preferably a material having a Young's modulus sufficiently larger than that of the transparent porous body 3 because it is necessary to fix the compressive strain in the Z direction of the transparent porous body 3, for example, synthetic resin, glass, wood, metal, etc. Various materials can be used, but in the case of using a material having a large difference in coefficient of thermal expansion from that of the plate glass 2 such as metal, in advance, an appropriate compressive strain is ensured after thermal expansion or thermal contraction. It is necessary to apply a large compression strain. However, even in the case of an aluminum material, since the thermal expansion coefficient of aluminum is 0.23 × 10 ⁻⁴ / K, even if the ambient temperature changes by 50 ° C. from the design temperature, the variation in compressive strain is about 0.1%. There is no need to apply excessive compression strain.

  Next, a method for assembling the multilayer glass 1 shown in FIG. 1 will be briefly described with reference to FIG. 2 (a) and 2 (b) are views showing the cross-sectional structure of the multilayer glass 1 before and after applying compressive strain to the transparent porous body 3 in the same cross section as FIG. As shown in FIG. 2 (a), one of the two glass plates 2 is fixed, and pressure F is applied to the other side from the Z direction outer side (upper side in the figure) to push the transparent porous body 3 in the Z direction. . As a result, as shown in FIG. 2 (b), when the transparent porous body 3 having a thickness T before compression strain is changed to a thickness (T−ΔT), the transparent porous body 3 is tightened from both sides. The window frame 5 is fitted from the outside in the X and Y directions to the outer periphery of the two sheet glasses 2 in the state of being sandwiched, and the Z direction outer surfaces 2c and 2d of the outer periphery of each sheet glass 2 are sandwiched in the Z direction. The thickness (T−ΔT) is fixed. Here, there is a large difference in Young's modulus between the plate glass 2 and the transparent porous body 3, and the Young's modulus of the transparent porous body 3 is about four orders of magnitude smaller than that of the plate glass 2, so only the outer periphery of the plate glass 2 is fixed by the window frame 5. Thus, the entire surface of the transparent porous body 3 can be tightened in the Z direction. As described above, the transparent porous body 3 is preliminarily provided with the compressive strain SCz (corresponding to the first compressive strain) in the Z direction and the compressive strain SCxy (corresponding to the second compressive strain) in the X and Y directions. become.

  In the case shown in FIG. 2, the compressive strain SCz in the Z direction is given by the following equation (1). In addition, if the expansions ΔLx, ΔLy in the X and Y directions are not suppressed by the stopper 4 due to the compression strain SCz in the Z direction, the relationship between the expansions ΔLx, ΔLy, the compression strain SCz, and the Poisson ratio Rp is assumed to be Rp. The following formula 2 is obtained. Here, Lx and Ly are the lengths of the transparent porous body 3 in the X and Y directions before compression.

(Equation 1)
SCz = ΔT / T
(Equation 2)
Rp = (ΔL / L) / (ΔT / T)
ΔL / L = ΔLx / Lx = ΔLy / Ly

  Therefore, the compression distortion SCxy generated in the X and Y directions is approximately given by the following formula 3 when ΔL / L is small.

(Equation 3)
SCxy = ΔL / (ΔL + L) ≈ΔL / L = Rp · SCz

  Next, the magnitude | size of the compressive strain previously provided to the transparent porous body 3 of the multilayer glass 1 shown in FIG. 1 is demonstrated. Here, the following is assumed as the mechanical performance required for the multilayer glass 1. That is, when the length of the plate glass 2 in the X direction is 2 m, the tensile strain generated in the transparent porous body 3 when the curvature with a curvature radius of 5 m is generated by the external pressure is offset by the compression strain applied in advance, It is a requirement that the transparent porous body 3 does not break due to tensile strain.

  When the position of the window frame 5 of the multilayer glass 1 in the X and Y directions is fixed, and both ends of the plate glass 2 in the X and Y directions are fixed to the window frame 5, the distance between both ends of the plate glass 2 in the X direction is Restrained to 2m. In this state, when the plate glass 2 is curved with a curvature radius of 5 m, the length of the plate glass 2 along the curved surface extends to about 2.0136 m as schematically shown in FIG. That is, about 0.68% tensile strain is generated in the glass plate 2 along the curved surface. Similarly, the transparent porous body 3 sandwiched between two plate glasses 2 is also curved with a curvature radius of 5 m.

  When the movement of the transparent porous body 3 is completely restrained by the inner side surfaces 2a, 2b of the plate glass 2 by the frictional force between the inner side surfaces 2a, 2b of the plate glass 2 and the transparent porous body 3, the transparent porous body 3 The same tensile strain as that of the plate glass 2 occurs along the curved surface of the plate glass 2. That is, a tensile strain STx of about 0.68% is generated in the curved X direction. The tensile strain STy corresponding to the length of the glass sheet 2 in the Y direction is also generated in the curved Y direction. However, since the length in the Y direction is shorter than the length in the X direction, the tensile strain STy is the tensile strain. It is smaller than STx.

  In the present embodiment, in order to cancel the tensile strains STx and STy with the compression strain SCxy previously applied in the X and Y directions, the compression strain SCxy is set to a value equal to or greater than the tensile strains STx and STy, for example, 0.7%. . Here, assuming a case where the Poisson's ratio Rp is 0.2, the compression strain SCz to be applied in advance in the Z direction is 3.5% from the above equation (3). The methylated silica xerogel used in the present embodiment has a very large compression limit strain of 80% as described above, and therefore does not break at a compression strain SCz of 3.5%. Here, even if the compression strain SCz previously applied in the Z direction changes by 0.1% due to thermal expansion or contraction, the compression strain SCxy previously applied in the X and Y directions only changes by 0.02%. This is sufficient for a tensile strain STx of about 0.68%.

  When there is no frictional force between the inner side surfaces 2a, 2b of the plate glass 2 and the transparent porous body 3, and the movement of the transparent porous body 3 is not restrained by the inner side surfaces 2a, 2b of the plate glass 2, it occurs in the curved transparent porous body. Since the strain is not constrained from the inner side surfaces 2a and 2b of the plate glass 2, it becomes tensile strain on the convex portion side of the curved surface and compressive strain on the concave portion side. When the thickness of the transparent porous body 3 is about 10 mm, the maximum tensile strain generated in the direction parallel to the surfaces of the two sheet glasses 2 is about 0.1% with respect to the curvature having a curvature radius of 5 m. The tensile strain is a small value compared to the tensile strain STx (0.68%) when the movement of the transparent porous body 3 is completely restrained by the inner side surfaces 2a and 2b of the plate glass 2. Actually, the contact state between the inner side surfaces 2a and 2b of the plate glass 2 and the transparent porous body 3 is such that the movement of the transparent porous body 3 is completely restricted by the inner side surfaces 2a and 2b of the plate glass 2. 3 is in a state where it is not constrained by the inner side surfaces 2a and 2b of the plate glass 2 or in an intermediate state thereof, the movement of the transparent porous body 3 is the maximum tensile strain to be predicted. It is sufficient to assume a case where the inner surfaces 2a and 2b are completely restrained.

  If the length of the glass sheet 2 in the X and Y directions is longer than 2 m, it is necessary to increase the compression strain SCz to be applied in advance in the Z direction according to the length. Moreover, if the length of the plate glass 2 in the X and Y directions is shorter than 2 m, the compressive strain SCz to be applied in advance in the Z direction can be reduced according to the length. However, when the length of the plate glass 2 in the X and Y directions is shortened, the movement of the transparent porous body 3 is parallel to the surfaces of the two plate glasses 2 in a state where the movement of the transparent porous body 3 is not constrained by the inner side surfaces 2a and 2b of the plate glass 2. The maximum tensile strain that is generated may be greater than the tensile strains STx and STy when the movement of the transparent porous body 3 is completely restrained by the inner side surfaces 2a and 2b of the plate glass 2, so whichever is greater Will be treated as the maximum expected tensile strain.

Second Embodiment
Next, the multi-layer glass 7 according to the second embodiment of the present invention will be described. As shown in FIG. 4, the multilayer glass 7 according to the second embodiment of the present invention includes two sheet glasses 2, a flat transparent porous body 3 sandwiched between the two sheet glasses 2, a stopper 4, and a spacer. A member 8, a sealing material 9, and a window frame 5 are provided. FIG. 4 is a cross-sectional view showing a schematic structure of the multilayer glass 1 in a cross section (XZ cross section or YZ cross section) perpendicular to the surfaces of the two sheet glasses 2. In FIG. 4, portions common to the multi-layer glass 1 according to the first embodiment of FIG.

  The difference between the multilayer glass 7 according to the second embodiment and the multilayer glass 1 according to the first embodiment is that an assembly method of the multilayer glass 7 and compression applied in advance in the Z direction to the transparent porous body 3. The strain SCz is applied and the spacer member 8 and the sealing material 9 are provided, and these differences are related to each other. Since the two glass sheets 2, the stopper 4, and the window frame 5 are the same as the multi-layer glass 1 according to the first embodiment, the overlapping description is omitted.

  The spacer member 8 is provided between the two sheet glasses 2 between the stopper 4 and the window frame 5, and is hermetically sealed between the inner surfaces 2 a and 2 b of the two sheet glasses 2 and the spacer member 8. A stop material 9 is provided. In order to hermetically seal the internal space surrounded by the two plate glasses 2 and the spacer member 8 by the spacer member 8 and the sealing material 9, the spacer member 8 needs to be an airtight material, for example, synthetic resin, Glass, metal, etc. can be used. The sealing material 9 may be appropriately selected from materials that can be hermetically sealed between the inner side surfaces 2a and 2b of the two glass sheets 2 and the spacer member 8, for example, resin adhesion such as glass frit and epoxy resin. Sealants, butyl rubber, etc. can be used.

  Next, a method for assembling the multilayer glass 7 shown in FIG. 4 will be briefly described with reference to FIG. FIGS. 5A and 5B are views showing the cross-sectional structures of the multilayer glass 7 before and after applying compressive strain to the transparent porous body 3 before attaching the window frame 5 in the same cross section as FIG. . As shown in FIG. 5A, the internal space surrounded by the two glass sheets 2 and the spacer member 8 is evacuated to decompress the gas phase portion of the transparent porous body 3. The transparent porous body 3 is pushed in the Z direction by applying a pressure F from both sides of the two glass sheets 2 due to the difference between the internal pressure of the gas phase portion and the atmospheric pressure outside the two glass sheets 2. As a result, as shown in FIG. 2 (b), when the transparent porous body 3 having the thickness T before the compression strain is changed to the thickness (T−ΔT), the sealing material 9 is cured, The internal space surrounded by the two plate glasses 2 and the spacer member 8 is hermetically sealed. Thereby, the application state of the pressure F is maintained. Subsequently, the window frame 5 is fitted from the outside in the X and Y directions to the outer periphery of the two sheet glasses 2 in a state where the transparent porous body 3 is tightened from both sides at atmospheric pressure, and the Z direction outer side surface of each outer periphery of each sheet glass 2 By sandwiching 2c and 2d in the Z direction and fixing the thickness (T-ΔT) of the transparent porous body 3, a multilayer glass 7 shown in FIG. 4 is obtained.

  As in the case of the first embodiment, the multilayer glass 7 assembled by the above assembling method is subjected to the compressive strain SCz (the first compressive strain is given to the transparent porous body 3 by Equation 1 in the Z direction). Is equivalent to the compression strain SCxy (corresponding to the second compression strain) given by Equation 3 in the X and Y directions.

  The degree of vacuum in the internal space surrounded by the two plate glasses 2 and the spacer member 8 may be set so that the pressure F is balanced with the compressive stress Fc to which the compressive strain SCz given by Equation 1 is applied. The compressive stress Fc is derived from the characteristics between the compressive strain SCz and the compressive stress Fc of the transparent porous body 3 to be used. Moreover, since atmospheric pressure fluctuates according to weather conditions, the gas phase portion of the transparent porous body 3 may be depressurized in anticipation that the pressure F decreases due to a decrease in atmospheric pressure. Assuming the same requirements as in the case of the first embodiment as the mechanical performance required for the multi-layer glass 1, the above-described method is used to apply a compressive strain SCz of 3.5% or more in the Z direction in advance. A degree of vacuum of about 0.5 ata (≈0.049 MPaA) is sufficient.

Hereinafter, another embodiment will be described.
<1> In the first and second embodiments described above, the stopper 4 includes two sheet glasses 2 at the outer peripheral portion of the end surface facing the X and Y directions of the transparent porous body 3 as shown in FIGS. 1 and 4. A structure having a gasket 6 between the inner side surface 2b of the glass sheet 2 and the tip of the stopper 4, which is fixed to the inner side surface 2a of the two glass sheets 2 and protrudes toward the inner side surface 2b of the other side of the two glass sheets 2. However, the structure of the stopper 4 is not limited to the structure shown in FIGS.

  If the stopper 4 has a structure capable of suppressing expansion in the X and Y directions when the transparent porous body 3 is applied with a compressive strain SCz in the Z direction, the purpose thereof is achieved. Is not necessarily required. For example, when the movement of the transparent porous body 3 is completely restrained by the inner side surfaces 2a and 2b of the plate glass 2 by the frictional force between the inner side surfaces 2a and 2b of the plate glass 2 and the transparent porous body 3, FIG. The member of the stopper 4 as shown in FIG. 4 is unnecessary. Further, when the frictional force between the inner side surfaces 2a, 2b of the plate glass 2 and the transparent porous body 3 is too small to function as a stopper, for example, as shown in FIG. 6, the inner side surfaces 2a, 2b of the plate glass 2 The outer peripheral portions of the inner side surfaces 2a and 2b may be processed into rough surfaces (arrows S) so as to increase the frictional force between the transparent porous body 3 and the transparent porous body 3. Furthermore, by aligning the end portions of the two plate glasses 2 and the transparent porous body 3, the window frame 5 can also be used as a stopper after the compression strain SCz is applied.

  Further, in the stopper shown in FIGS. 1 and 4, if it is not necessary to hermetically seal the gas phase portion of the transparent porous body 3 surrounded by the two glass sheets 2 and the stopper 4, the gasket 6 may not be provided. Absent.

  <2> In the second embodiment, the stopper 4 and the spacer member 8 are both provided. However, the spacer member 8 and the sealing material 9 are not provided, and the front end portion of the stopper 4 and the plate glass 2 on the other side. The gasket 6 may be hermetically sealed only with the gasket 6 provided between the inner side surfaces 2b. Furthermore, instead of the gasket 6, a sealing material 9 is provided so that the sealing material 9 between the front end portion of the stopper 4 and the inner side surface 2 b of the other plate glass 2 is cured after the compression strain SCz is applied. It doesn't matter.

  <3> In the above embodiment, as a method of applying the pressure F for preliminarily applying the compressive strain SCz in the Z direction to the transparent porous body 3, a method of tightening two plate glasses 2 in the Z direction by the window frame 5 (first Embodiment) and a method in which the gas phase portion of the transparent porous body 3 is depressurized and the two plate glasses 2 are tightened in the Z direction by the difference between the internal pressure of the gas phase portion and the atmospheric pressure outside the two plate glasses 2 ( Although the second embodiment has been described, it is also a preferred embodiment to combine the fastening methods of the first and second embodiments. That is, when the fastening methods of the first and second embodiments are combined, the initial fastening state can be maintained by the window frame 5 even if the atmospheric pressure decreases after the two glass sheets 2 are fastened in the Z direction.

  <4> In the second embodiment, the gas phase portion of the transparent porous body 3 is depressurized to about 0.5 ata, but it may be further depressurized to improve heat insulation. In this case, the compression strain SCz in the Z direction further increases, but there is no problem as long as it is below the compression limit strain. In the second embodiment, since the methylated silica xerogel having a compressive strength of about 10 MPa is used for the transparent porous body 3, the pressure F applied in the Z direction even when the gas phase portion of the transparent porous body 3 is in a high vacuum state. No problem at all because it is at most atmospheric pressure.

  <5> In the first and second embodiments, it is assumed that the transparent porous body 3 uses a methylated silica xerogel having a compressive strength of about 10 MPa and a compression limit strain of about 60% to 80%. However, the transparent porous body 3 is not limited to methylated silica xerogel. A transparent porous material having a compression limit strain smaller than that of methylated silica xerogel may be used as long as the compression strain SCz applied in the Z direction in advance according to the specifications of the multilayer glass 1 as a product is less than the compression limit strain. I do not care.

  For example, when the length of the plate glass 2 in the X direction is 1 m, the length of the plate glass 2 along the curved surface when the curvature of the curvature radius is 5 m is generated by the external pressure is extended to about 1.0017 m. In other words, the plate glass 2 is subjected to a tensile strain of about 0.17% along the curved surface in the X direction. Therefore, the transparent porous body 3 has a tensile strain STx of about 0.17% that is the same as that of the plate glass 2 along the curved surface of the plate glass 2. In the transparent porous body 3 having a Poisson's ratio Rp of 0.2, the compressive strain SCz applied in advance in the Z direction may be 0.85% or more. Therefore, it can be seen that even the transparent porous body 3 having a compression limit strain of about 1% can be used. Conventional silica aerogels (inorganic amorphous gels having a skeleton structure composed of silicon and oxygen) have a compression limit strain of about 1%. Therefore, if the length of the plate glass 2 in the X and Y directions is about 1 m. The transparent porous body 3 can be used.

  Even if the transparent porous body 3 has a compression limit strain of about 1%, there is no frictional force between the inner side surfaces 2a, 2b of the plate glass 2 and the transparent porous body 3, and the movement of the transparent porous body 3 is caused by the movement of the plate glass 2. If the inner side surfaces 2a and 2b are not restrained, the tensile strains STx and STy generated in the X and Y directions in the curved state with respect to the transparent porous body 3 are greatly reduced as described above. Even when the length in the direction is about 2 m, since the tensile strains STx and STy are about 0.1%, in the transparent porous body 3 having a Poisson's ratio Rp of 0.2, the compressive strain SCz applied in advance in the Z direction is 0.5% or more is good. Therefore, it can be seen that even a transparent porous body 3 having a compression limit strain of about 1% like a conventional silica airgel can be used. Further, even when a frictional force is generated between the inner side surfaces 2a, 2b of the plate glass 2 and the transparent porous body 3, the contact surface between the inner side surfaces 2a, 2b of the plate glass 2 of the transparent porous body 3 is made of an organic polymer or the like. By carrying out the process of reducing the frictional force by coating with, it becomes possible to substantially increase the compression limit strain of the transparent porous body 3.

  Further, the material of the transparent porous body 3 is not limited to the skeleton structure having silicon and oxygen. For example, an airgel that does not absorb light, such as titania or alumina, can be used as a material for the transparent porous body 3 in principle.

  <6> In the first and second embodiments described above, the compressive strain SCxy preliminarily applied to the transparent porous body 3 in the curved X and Y directions is predicted to occur in the curved X and Y directions. Although the case where a value equal to or greater than the maximum value of the tensile strains STx and STy has been described, even if the compression strain SCxy is less than the tensile strains STx and STy, the tensile strain generated after canceling out the compression strain SCxy is a tensile strain. Less than the limit strain is sufficient. Therefore, even if the compressive strain SCxy previously applied in the X and Y directions in the curved state is not applied with a value greater than the maximum value of the tensile strains STx and STy expected to occur in the X and Y directions in the curved state, If the tensile limit strain of the porous body 3 can be accurately grasped, the transparent porous body 3 can be prevented from being broken by the tensile strain caused by deformation such as bending due to external pressure by the principle of the present invention.

  <7> In the first and second embodiments, the gas phase component of the transparent porous body 3 is not particularly specified. However, it is also preferable to use a rare gas other than air or the like as the gas phase component. Air is usually contained in the gas phase portion of the transparent porous body 3. However, since nitrogen, oxygen, and water, which are the main components of air, are polyatomic molecules, they have vibration and rotation energy in addition to the kinetic energy of the whole molecule, and have high thermal conductivity. Therefore, by using a rare gas as the gas phase component of the transparent porous body 3, heat conduction due to the gas phase component of the transparent porous body 3 can be reduced, and the heat insulation performance can be improved. The gas phase component of the transparent porous body 3 is preferably a rare gas such as Ar (argon) having a molecular weight as large as possible.

  In the first embodiment, when a rare gas is used as the gas phase component of the transparent porous body 3, it is necessary to hermetically seal regardless of whether or not the gas phase portion of the transparent porous body 3 is decompressed. Therefore, in the structure shown in FIG. 1, it is preferable to provide a gasket 6 between the inner side surface 2 b of the other glass plate 2 and the tip of the stopper 4.

  The highly heat insulating double glazing according to the present invention can be used as double glazing provided on the wall of a building such as a house or a building.

Sectional drawing which shows typically the schematic structure in 1st Embodiment of the multilayer glass concerning this invention Sectional drawing which shows typically the cross-sectional structure of the multilayer glass before and after the compressive strain provision with respect to the transparent porous body of the multilayer glass shown in FIG. The figure explaining the tensile distortion which arises in the plate glass of the multilayer glass shown in FIG. Sectional drawing which shows typically the schematic structure in 2nd Embodiment of the multilayer glass concerning this invention Sectional drawing which shows typically the cross-sectional structure before attaching the window frame of the multilayer glass before and after the compressive strain provision with respect to the transparent porous body of the multilayer glass shown in FIG. Sectional drawing which shows typically schematic structure in other embodiment which does not provide the stopper member of the multilayer glass which concerns on this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 7: Multi-layer glass 2: Plate glass 2a, 2b: Inner side surface 2c, 2d of plate glass Outer peripheral part of plate glass 3: Transparent porous body 4: Stopper 4a: Recessed portion of stopper 5: Window frame 6: Gasket 8: Spacer member 9: Sealing material F: Pressure for pre-applying compressive strain in the Z direction S: Rough surface

Claims (9)

A multi-layer glass having a laminated structure in which a flat transparent porous body that transmits visible light is sandwiched between two plate glasses,
The transparent porous body has a compression limit strain larger than a tensile limit strain,
A multilayer glass characterized in that a compressive strain is applied in advance to the transparent porous body.   The transparent porous material is applied so that a compressive strain equal to or greater than the maximum tensile strain expected to be generated in the transparent porous body due to deformation due to external pressure applied to the two plate glasses is applied in the direction of the predicted tensile strain. 2. The multilayer glass according to claim 1, wherein a compression strain is applied to the body in advance. By the pressure applied to the transparent porous body in the thickness direction of the transparent porous body from the two plate glasses, a first compressive strain is previously applied to the transparent porous body in the thickness direction,
The transparent porous body is sandwiched between the two plate glasses in a state in which the transparent porous body is prevented from expanding in a direction parallel to the surfaces of the two plate glasses. 3. The multilayer glass according to claim 1, wherein a second compressive strain is applied in advance in a direction parallel to the surfaces of the two sheet glasses. By tightening the two plate glasses in the thickness direction of the transparent porous body by a window frame sandwiching the two plate glasses in the thickness direction of the transparent porous body, the first compression is performed on the transparent porous body. Distortion is applied in advance,
The second compressive strain is preliminarily applied to the transparent porous body by preventing the transparent porous body from expanding in a direction parallel to the surfaces of the two plate glasses. The multilayer glass according to claim 3. By depressurizing the gas phase in the transparent porous body, the first compressive strain is preliminarily applied to the transparent porous body by the atmospheric pressure applied from both sides of the two sheet glasses,
The second compressive strain is preliminarily applied to the transparent porous body by preventing the transparent porous body from expanding in a direction parallel to the surfaces of the two plate glasses. The multilayer glass according to claim 3. The compression limit strain inherent to the transparent porous body is greater than 3.5%,
6. The multilayer glass according to claim 3, wherein the first compression strain is 3.5% or more and less than the compression limit strain inherent to the transparent porous body.   The multilayer glass according to any one of claims 1 to 6, wherein the transparent porous body is an inorganic or organic-inorganic hybrid amorphous gel.   The multilayer glass according to claim 7, wherein the transparent porous body contains silicon and oxygen in a skeleton structure. The multilayer glass according to claim 8, wherein the transparent porous body is a methylated silica xerogel.

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