Vacuum heat insulating panel and device comprising the same

Abstract

To provide a vacuum heat insulating panel with high heat insulation.SOLUTION: A vacuum heat insulating panel of the present invention comprises a core material formed from a plurality of laminated films, and an outer packaging material that encapsulates the core material under reduced pressure. The film has projections and recesses on an opposite surface to an adjacent other film, and allows gas to accumulate in cavities formed by the projections and recesses. Alternatively, the film has a cavity formed by separating a portion of the opposite surface from the adjacent other film, and allows the gas to accumulate in the cavity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vacuum insulation panel and an apparatus equipped with the same. [Background technology]

[0002] Multilayer insulation materials such as MLI (Multilayer Insulation) are known, which have a multilayer structure consisting of multiple insulation sheets and spacer sheets interposed between them. The insulation sheets block heat radiation, while the spacer sheets prevent contact between the insulation sheets and suppress heat transfer, thereby achieving high insulation effectiveness. For example, Patent Document 1 discloses that, while it is known to alternately stack these two types of sheets, an uneven stacking structure is used in which fewer spacers and more Al sheets are stacked on the high-temperature side, and fewer Al sheets and more spacers are stacked on the low-temperature side, thereby improving insulation effectiveness. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-151181 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a heat insulating structure having a laminated structure different from the non-uniform laminated structure described in Patent Document 1. [Means for solving the problem]

[0005] The vacuum insulation material of the present invention comprises a core material including laminated insulation sheets and an outer packaging material that seals the core material under reduced pressure, and is characterized in that the core material does not have a spacer sheet with a higher porosity than the insulation sheet, or has spacer sheets in less than half the number of layers of the core material. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 2 is a partial cross-sectional view of the core material of the first embodiment. [Figure 2] Graph illustrating the heat insulating performance of core materials of Examples and Comparative Examples. [Figure 3] A graph showing the vertical axis of the graph in Figure 2 on a linear scale. [Figure 4A] Partial cross-section of a vacuum insulation panel with uncompressed core. [Figure 4B] Partial cross-section of a vacuum insulation panel using compressed core material. [Figure 5] FIG. 10 is a partial cross-sectional view of another embodiment of a core material. [Figure 6] FIG. 10 is an enlarged cross-sectional view of two adjacent films in another embodiment of the core material. [Figure 7] Photograph of the surface of a film that has been subjected to transfer processing in a core material of another embodiment. [Figure 8] FIG. 10 is an enlarged cross-sectional view of two adjacent films in another embodiment of the core material. [Figure 9] Partial cross-sectional view of a vacuum insulation panel. [Figure 10] Partial cross-sectional view of a vacuum insulation panel. [Figure 11] FIG. 1 is a front view of a refrigerator as an example of equipment equipped with a vacuum insulation panel. [Figure 12] A cross-sectional view of FIG. 11 in the direction A. [Figure 13] Enlarged view of area B in Figure 12. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, when a numerical range is expressed as "A to B," it means "not less than A and not more than B."

[0008] Overview The core material according to an embodiment of the present invention comprises multiple insulating sheets, each coated with a metal coating as a radiation shield, laminated on the surface of a film, such as PET (polyethylene terephthalate), which acts as a base material to enhance sheet strength. The coating is made of a metal, such as aluminum, that reflects electromagnetic waves in the thickness direction of the insulating sheet and is formed by a method such as vapor deposition. If a spacer sheet with a mesh structure, such as a nonwoven fabric, with lower solid-state thermal conductivity than the radiation shield is interposed between the two insulating sheets, the contact between the insulating sheets reduces solid-state heat transfer in the thickness direction of the core material, increasing the thermal resistance along the heat transfer path. Meanwhile, when the thickness dimension of the core material is limited, the number of sheets that can be stacked is reduced. Therefore, the inventors of the present invention conducted extensive research into the configurations of insulating sheets and spacer sheets that would enhance the insulating properties of the core material within the limited core thickness dimension.

[0009] First Embodiment FIG. 1 is a partial cross-sectional view of a core material 106 according to the first embodiment. As shown in FIG. 1, the core material 106 has a portion in which a plurality of heat insulating sheets 103, each having a coating 102 applied to the surface of a film 101, are laminated in the thickness direction. The coating 102 is a metal such as aluminum formed by vapor deposition, and is preferably made of a material with a lower emissivity than the film 101. The film 101 is a resin film such as PET, PP (polypropylene), or PE (polyethylene) formed into a film shape by a known method such as extrusion molding or solution casting. Here, PET (polyethylene terephthalate) is used as the film 101, which is stronger than the coating 102 and can make the heat insulating sheet 103 less likely to tear. The film 101 is not essential, and may have a porous structure such as a fiber sheet or filter paper as long as it can make the heat insulating sheet 103 less likely to tear.

[0010] Figure 2 is a graph showing the equivalent thermal conductivity (vertical axis) of the core material 106 versus the pressure (horizontal axis) inside a vacuum chamber when the core materials of the examples and comparative examples are placed in a reduced-pressure environment created inside the vacuum chamber. As shown in the figure, the dimension is [mW / m·k], and the thickness of the core material 106 is the value per unit length. Figure 3 shows the vertical axis of the graph in Figure 2 on a linear scale.

[0011] To measure the equivalent thermal conductivity, a GHP 456 Titan manufactured by NETZSCH, Germany, was used as a thermal conductivity measuring instrument.

[0012] <Non-compression conditions for core 106> The core material 106 was placed in the space inside the vacuum chamber so that the thickness direction was vertical, and the measurement was performed with the measurement surfaces of the thermal conductivity measuring instrument in contact with the top and bottom of the core material 106. The measurement was performed with a compressive load equivalent to the mass of the measurement surface of the thermal conductivity measuring instrument applied to the core material 106. In other words, the core material 106 was subjected to almost no load, which is referred to as a non-compression condition.

[0013] FIG. 4A is a partial cross-sectional view of a vacuum insulation panel 10 containing an uncompressed core material 106. The core material 106 is housed in an outer case 109 made of resin or metal and connected to the inside and outside of the case. This is then housed in a flexible, bag-like outer packaging material 105 made of a gas barrier film. When this is placed in a vacuum chamber and a vacuum is drawn, the interior of the outer packaging material 105 and the outer case 109 are depressurized. The outer packaging material 105 shrinks as the pressure is reduced and adheres tightly to the outer case 109, but the outer case 109 is hard and strong enough to withstand deformation or destruction even when subjected to atmospheric pressure. The opening of the outer packaging material 105 is sealed, for example, with a heat seal 107. The vacuum insulation panel 10 can be produced in this manner. While FIG. 4A depicts the outer packaging material 105 and outer case 109 as being spaced apart, in reality, the outer packaging material 105 shrinks as the pressure is reduced and adheres tightly to the outer case 109.

[0014] Example 1 The core material 106 in Example 1 was made by laminating 400 layers of heat insulating sheets 103, each of which had an aluminum coating 102 vapor-deposited on the surface of a PET film 101. The average thickness of each heat insulating sheet 103 was approximately 12 micrometers. The horizontal axis represents the air pressure inside the vacuum chamber, and the equivalent thermal conductivity was measured while changing the air pressure inside the vacuum chamber. The plots "●" are connected by a solid line. Each plot represents the acquired data value.

[0015] (Comparative Example 1) A core material consisting of 100 layers of nonwoven fabric, each about 5 micrometers thick, was used as Comparative Example 1. The thermal conductivity versus the amount of pressure reduction is plotted and shown by a dashed line connected by "■".

[0016] (Comparative Example 2) As Comparative Example 2, the thermal conductivity of a core material made by alternately stacking 100 layers of a nonwoven fabric similar to that of Comparative Example 1 and a sheet 103 made under the same conditions as in Example 1 is shown by a dotted line connected by a plot "▲".

[0017] <Compression conditions for heartwood> The core material was placed in a flexible, bag-shaped outer packaging material with gas barrier properties, and the pressure inside the outer packaging material was reduced before sealing. The core material was subjected to an atmospheric pressure load as the outer packaging material contracted, and this state is called the compressed condition. The decompressed outer packaging material was placed under atmospheric pressure, and measurements were taken with the measuring surface of the thermal conductivity measuring instrument in contact with the outer packaging material, as in the non-compressed condition. The horizontal axis represents the atmospheric pressure inside the outer packaging material.

[0018] FIG. 4B is a partial cross-sectional view of a vacuum insulation panel 20 containing a core material 106 under compressed conditions. The core material 106 is directly housed in a flexible, bag-like outer packaging material 105 made of a gas barrier film. When this is placed in a vacuum chamber and a vacuum is drawn, the outer packaging material 105 shrinks as the pressure decreases, adhering to the core material 106. The opening of the outer packaging material 105 is sealed, for example, with a heat seal 107. In this manner, the vacuum insulation panel 20 can be produced. Although the outer packaging material 105 and the core material 106 are depicted as being spaced apart in FIG. 4B, in reality, the outer packaging material 105 shrinks as the pressure decreases, adhering to the core material 106. The core material 106 is compressed under a load equivalent to atmospheric pressure.

[0019] (Example 1-1) The core material 106 used in Example 1 was placed in an outer packaging material 105 and the pressure inside was reduced. Since it is difficult to change the pressure inside the outer packaging material 105 after sealing, only one plot was obtained, which is indicated by "○" in Figure 2.

[0020] (Comparative Example 1-1) The core material used in Comparative Example 1 was prepared in the same manner as in Example 1-1. Again, only one plot was obtained, which is indicated by "□" in FIG.

[0021] (Comparative Example 1-2) The core material used in Comparative Example 2 was prepared in the same manner as in Example 1-1. Again, only one plot was obtained, which is indicated by "△" in FIG.

[0022] It should be noted that the acquired pressure values ​​(values ​​on the horizontal axis) do not match between Example 1-1 and Comparative Examples 1-1 and 1-2.

[0023] <Results for heartwood under non-compression conditions> [Thermal Conductivity] From Figure 2, when comparing the thermal conductivity of each example in a reduced pressure environment of 1 Pa or more and 10 Pa or less, core material 106 of Example 1 has the lowest thermal conductivity and has excellent insulating performance per unit thickness, followed by the core materials of Comparative Example 2 and Comparative Example 1.

[0024] From the results of Example 1 and Comparative Examples 1 and 2, from the viewpoint of thermal conductivity, it is preferable that the core material under non-compressed conditions has a higher proportion of insulating sheet 103, and it is preferable to use more insulating sheet 103 than, for example, to use one layer of insulating sheet 103 and one layer of spacer sheet alternately stacked in approximately equal numbers.

[0025] It is most preferable for the insulation sheets 103 to cover 100% of the core material 106, but spacer sheets can also be used in amounts less than half the number of layers of the core material 106. For example, 2, 3, 4 or more layers of insulation sheets can be stacked alternately with fewer spacer sheets, for example, 1, 2, 3 layers. Preferably, there is only one spacer sheet per layer. The insulation sheets 103 can cover, for example, 80% or more, 90% or more, or 100% of the number of layers of the core material 106.

[0026] Even if a portion of the spacer sheet is optionally included in the core material 106, it is preferable that the insulating sheet 103 be disposed in a majority on both sides in the thickness direction. That is, the ratio of the number of insulating sheet 103 layers to the total number of layers of the core material (number of insulating sheet 103 layers + number of spacer sheet layers) is more than 50% on both sides in the thickness direction of the core material, preferably 80% or more, more preferably 90% or more, and most preferably 100%. If the core material is configured so that one side has a higher proportion of insulating sheet 103 and the other side has a lower proportion, it is preferable that one side faces the higher temperature side and the other side faces the lower temperature side. This is because consideration must be given to the orientation of the core material, which may result in assembly errors.

[0027] The results for the core material in an uncompressed condition are expected to reproduce the trends in the thermal insulation performance of the vacuum insulation panel 10.

[0028] [Sensitivity to vacuum] Fig. 3 shows the graph shown in Fig. 2 with the vertical axis in a linear scale. The plots for Example 1, Comparative Example 1, and Comparative Example 2 are the same data as in Fig. 3.

[0029] The change in equivalent thermal conductivity relative to the change in pressure inside the vacuum chamber indicates the sensitivity of the insulation to the degree of vacuum. A lower sensitivity is preferable because it increases resistance to performance degradation due to gas intrusion into the vacuum insulation panel 10 and gas generation from the core material.

[0030] In Figure 3, an increase in pressure, shown on the horizontal axis, means a decrease in the degree of vacuum, and an increase in equivalent thermal conductivity, shown on the vertical axis, means a decrease in thermal insulation. Comparing the individual Examples and Comparative Examples, core material 106 of Example 1 has the smallest slope, i.e., the smallest sensitivity. This is followed by Comparative Example 1 and Comparative Example 2, in that order, with the highest sensitivity.

[0031] The sensitivity of the core material decreases as the porosity (volume of voids relative to the total volume) of the core material decreases. The film-like insulating sheet 103 used in Example 1 and Comparative Examples 1 and 2 has a lower porosity than the mesh-like spacer sheet used in Comparative Examples 1 and 2. Therefore, the porosity of the core material is lowest in Example 1, which consists only of insulating sheet 103, followed by Comparative Example 2, in which half the spacer sheets are used, and Comparative Example 1, in which the entire spacer sheet is used. In other words, from the perspective of sensitivity, it is preferable to have more layers of insulating sheet 103.

[0032] <Results for core wood under compression conditions> [Thermal Conductivity] Although direct comparison is not possible because the internal pressures (horizontal axis values) obtained for Example 1-1, Comparative Examples 1-1, and 1-2 are not consistent, the equivalent thermal conductivity increases with increasing internal pressure. Therefore, the insulating performance of Comparative Example 1-1, which has the lowest equivalent thermal conductivity despite the highest internal pressure, is the best, followed by Comparative Example 1-2 and Example 1-1. Thus, for the core material under compressed conditions, Comparative Example 1-1, which uses spacer sheets in all layers, is the best, and Example 1-1, which uses insulating sheets 103 in all layers, is the worst. It is estimated that the results for the core material under compressed conditions reproduce the thermal conductivity trends of the vacuum insulation panel 20.

[0033] The thermal conductivity of the core material is affected by the number of layers, not the thickness of each layer, such as the insulating sheet 103. Therefore, if the thickness of each layer of the insulating sheet 103 can be reduced to about one-third or less in the future, the thermal conductivity of Example 1-1 is expected to be superior to that of Comparative Example 1-1, which uses only a spacer sheet.

[0034] [Sensitivity to vacuum] As mentioned above, the sensitivity is determined by the porosity of the core material. Although the porosity is not necessarily constant throughout the range of internal pressure changes, it is safe to assume that the porosity of the mesh-like spacer sheet will never be lower than that of the film-like insulation sheet 103, which has a very low porosity to begin with, within the range of internal pressures of the core material used in vacuum insulation panels.

[0035] For this reason, from the viewpoint of the performance stability of the core material under both compressed and uncompressed conditions, it is preferable for the core material to be made up of a majority, preferably all, of insulating sheets 103 (even if spacer sheets are optionally included in the core material). From the viewpoint of eliminating the need to consider the orientation of the core material, it is preferable for the insulating sheets 103 to make up a majority on both sides in the thickness direction. In other words, the ratio of the number of insulating sheets 103 to the total number of layers of the core material (number of insulating sheets 103 layers + number of spacer sheets and other sheets) is more than 50% on both sides in the thickness direction of the core material, preferably 80% or more, more preferably 90% or more, and most preferably 100%. For example, suppose the core material is made up of 200 layers of sheets. In this case, the 100 layers on one side and the 100 layers on the other side each contain 51 or more layers (more than 50%) of insulating sheet 103, preferably 80 or more layers (80% or more), more preferably 90 or more layers (90% or more), and most preferably 100 layers (100%).

[0036] Furthermore, from the viewpoint of eliminating the need to consider the installation direction, it is even more preferable if the content of the insulating sheet is roughly uniform on both sides in the thickness direction. For example, the difference in the number of insulating sheet 103 layers between one side and the other side in the thickness direction of the core material can be 20% or less, preferably 10% or less, of the total number of layers. For example, in the above-mentioned core material consisting of 200 layers, if one side in the thickness direction has 100 insulating sheet 103 layers and the other side has 80 insulating sheet 103 layers, the difference in the number of layers is |100-80| / 200=10%.

[0037] <Reason for the different results under non-compressed and compressed heartwood conditions> Although the principle behind these results is not entirely clear, investigation suggests that solid-state heat transfer may have been suppressed more than expected when the core material 106 was kept uncompressed, as in Example 1. When the core material 106 is created by continuously stacking the insulating sheets 103, macroscopic irregularities due to the bending of each insulating sheet 103 and microscopic irregularities due to surface roughness are generated between adjacent insulating sheets 103, and it is understood that these irregularities create gaps. These gaps reduce the contact area between adjacent insulating sheets 103, suppressing solid-state heat conduction, and therefore low thermal conductivity may be maintained even when no spacer sheet is used to prevent contact between the insulating sheets 103.

[0038] On the other hand, the situation may have been different under the compression conditions of the core material. As the compressive load on the core material 106 increased, the contact area between adjacent sheets increased, which may have increased solid-state heat transfer and increased the influence of solid-state heat conduction. The influence of solid-state heat transfer became greater than that of radiative heat transfer, and it is possible that having more spacer sheets rather than insulating sheets 103 resulted in lower thermal conductivity and better insulating performance.

[0039] However, in terms of sensitivity, a larger amount of low-porosity insulating sheet 103 provides a more favorable result, so using the core material of Example 1-1 can still contribute to the stability of the insulating performance. In terms of insulating performance, if the thickness of each layer of insulating sheet 103 can be reduced and the number of layers can be increased, as described above, excellent results can be expected. This will be discussed below.

[0040] <Study on changing the thickness of each layer of the heat insulating sheet 103> The following explains how, by reducing the thickness of the insulating sheet 103 of the core 106 of the vacuum insulation panel 10 of Example 1-1 to one-third and tripling the number of layers, and thereby maintaining the thickness of the core 106 to form a vacuum insulation panel 20, it is possible to obtain low thermal conductivity, or in other words, high insulation performance, even under core compression conditions.

[0041] The thermal conductivity k [mW / m k] at a heat flow Q [W] is given by the following (Equation 1):

[0042]

number

[0043] Here, A is the area of ​​the insulation material [m^2], ΔT is the temperature difference between the two sides of the insulation material [K], and t is the thickness of the insulation material [m]. The PET film used as the film 101 for the insulation sheet 103 of the vacuum insulation panel 20 in Example 1-1 is easier to make thinner than mesh-like spacer sheets such as nonwoven fabrics, which require a certain degree of woven or tangled structure. If the thickness of the insulation sheet 103 in Example 1 is reduced to one-third while maintaining the total thickness t of the core material 106, the number of layers of the insulation sheet 103 can be tripled. When the number of layers is tripled, the thermal resistance triples and the heat flow Q becomes one-third, so the thermal conductivity k shown in (Equation 1) becomes one-third.

[0044] 2 is 4.2 mW / m·k, so it is estimated that by reducing the thickness of the insulating sheet 103 to one-third and increasing the number of layers by three times, the thermal conductivity k will be one-third, or 1.4 mW / m·k.The thermal conductivity of the vacuum insulation panel 20 of comparative example 1-2 is 2.1 mW / m·k, so it can be confirmed that the insulating performance of example 1-1 is higher than that of the vacuum insulation panel 20 using a core material consisting only of laminated spacer sheets 104.

[0045] <Other components of core wood 106> The heat insulating sheets 103 have low gas permeability so that gas molecules remaining between adjacent heat insulating sheets 103 in a reduced pressure environment do not move back and forth in the thickness direction of the core material 106. For example, a material with a gas permeability of 10,000 L / (m^2-s) or less can be used for the heat insulating sheets 103. A spacer sheet can have a higher gas permeability.

[0046] The core material 106, which has low gas permeability, also has the effect of reducing gas heat transfer. Gas heat transfer occurs when gas molecules remaining between adjacent insulation sheets 103 in a reduced pressure environment move back and forth between the insulation sheets 103. Gas flow can be divided into a molecular flow state and a viscous flow state depending on the mean free path M [m] of the gas molecules, which is calculated using the following formula, and the length of the space in which the gas molecules exist. The mean free path M [m] at an internal pressure P [Pa] is given by the following formula (2):

[0047]

number

[0048] Here, k is the Boltzmann constant (= 1.381 × 10-23 [J / K]), T is the absolute temperature [K], and d is the molecular diameter [m]. In the case of air, the mean free path can be calculated using a molecular diameter of d = 0.376 × 10-9 [m]. When the mean free path of gas molecules is smaller than the characteristic dimension of the space (thickness of the gap between layers, i.e., the compartment), the system is in a viscous flow state, i.e., collisions between gas molecules dominate the energy (heat) exchange phenomenon of the system. In a viscous flow state, the thermal conductivity of the gas is independent of pressure. Conversely, when the mean free path of gas molecules is larger than the characteristic dimension of the compartment, the system is in a molecular flow state, i.e., collisions between gas molecules and compartments dominate the heat exchange phenomenon of the system. In a molecular flow state, the thermal conductivity of the gas is proportional to the pressure, and the lower the pressure, the lower the thermal conductivity (higher the thermal insulation). For this reason, in this embodiment, the dimension in the thickness direction of the core material between adjacent insulating sheets 103 is made smaller than the mean free path of gas molecules, thereby maintaining a molecular flow state. By placing the core material in a reduced-pressure environment under these dimensions, the thermal conductivity is significantly reduced (thermal insulation is significantly improved) compared to a simple air layer. For example, when the vacuum level is 10 Pa, the mean free path of molecules is approximately 600 micrometers when the gas is atmospheric air and the temperature is 20°C, so making the dimension between sheets 103 less than 600 micrometers leads to a reduction in thermal conductivity. Further reducing the pressure in such a space can significantly reduce gas heat transfer, which contributes to the insulating properties of the core material.

[0049] (Promoting the creation of space) FIG. 5 is a partial cross-sectional view showing a core 306 of another embodiment, and FIG. 6 is an enlarged cross-sectional view of two adjacent films 301 in the core 306. The configuration of this embodiment can be configured identically to that of embodiment 1, except for the following points. A coating 302 is formed by vapor deposition on the opposing surfaces of two adjacent heat insulating sheets 303, and many minute irregularities 305 are formed on the surface of the coating 302. Methods for forming the irregularities include mechanical processes (in addition to vapor deposition, etc., as described here) such as transfer printing, graining, blasting, and embossing. FIG. 5 is a photograph of the film surface after transfer printing. As shown in FIG. 7, it can be seen that irregularities 305 are formed on the surface of the film 301. As a result, when the films 301 are stacked, adhesion between the opposing surfaces is reduced, making it easier for air pockets 304 to form.

[0050] It is also possible to apply the unevenness forming treatment to only one of the two adjacent sheets 303. Figure 8 is an enlarged cross-sectional view of two adjacent films 301 in the core material 306. In Figure 8, the upper film 301 has not been subjected to the unevenness forming treatment, while the lower film 301 has been. Even in this case, the unevenness 305 can be used to suppress adhesion between the opposing surfaces. Furthermore, since the unevenness forming treatment is not applied, the cost of producing the core material 306 can be reduced.

[0051] <Vacuum insulation panel 10, 20> FIG. 9 is a partial cross-sectional view of a vacuum insulation panel 10, 20 containing a core material (referred to as core material 406) according to one of the embodiments. The figure shows an outer case 402 containing the core material 406. That is, the vacuum insulation panel 10 (vacuum insulation panel) is depicted as having an uncompressed core material 406, but this is not limited thereto. The vacuum insulation panel 10 includes an outer packaging material 405 (gas barrier film) containing the outer case 402. The inside of the bag-shaped outer packaging material 405 is reduced in pressure to 10 Pa or less, and then a heat seal 407 is formed to hermetically seal the outer packaging material 405, thereby obtaining the vacuum insulation panel 10. The pressure inside the outer packaging material 405 may be, for example, 1 Pa or more, from the viewpoint of mass production.

[0052] Since pressure close to atmospheric pressure is applied from the outside to outer case 402, it must be strong enough to withstand the pressure, and resin or metal can be used. The inside of outer case 402 (the side that houses core material 406) is connected to the outside (the side where outer packaging material 405 is located), and the inside is also in a vacuum state.

[0053] The vacuum insulation panels 10, 20 have holes 408 extending in the thickness direction of the core material 406, for example, approximately in the center when viewed in the thickness direction of the core material 406. Adsorbent 409 is disposed in the holes 408, and the holes 408 are provided in the outermost layer of the core material 406 (i.e., one or both ends in the thickness direction). This makes it possible to adsorb gases that penetrate from outside the outer packaging material 405 due to aging or other reasons, and the insulating performance of the vacuum insulation panel 10 can be maintained for a long period of time.

[0054] 10 is a partial cross-sectional view of another embodiment in which an adsorbent 409 is housed inside a core material 406. The holes 4080 are confined to the interior and do not reach the outermost layer of the core material 406. If the adsorbent 409 were placed between sheets of the core material 406, the volume of the adsorbent 409 would increase the thickness of the core material 406 in some areas, which could cause the core material 406 to lose its flatness and ultimately reduce the flatness of the vacuum insulation panel 10. For this reason, by providing holes 408, 4080 that extend in the thickness direction, the thickness of the core material 406 can be maintained even when the adsorbent 409 is housed therein.

[0055] The adsorbent 409 may not be disposed in the holes 408, 4080, but may be sandwiched and dispersed between the sheets constituting the core material 406. When the core material 406 is made of a film with low gas permeability as in Example 1, it is desirable to dispose the adsorbent 409 in different regions between the sheets.

[0056] <Devices equipped with vacuum insulation panels 10 and 20> Vacuum insulation panels 10, 20 can be installed in various devices that require thermal insulation, such as refrigerators and hot water storage tanks for water heaters. Fig. 11 is a front view of refrigerator 200, and Fig. 12 is a cross-sectional view from direction A in Fig. 11. Refrigerator 200 has a metal outer box 201 and an inner box 202 that is made of, for example, resin. Vacuum insulation panels 10, 20 are arranged between outer box 201 and inner box 202.

[0057] The vacuum insulation panel 10 can be disposed between the outer box 201 and the inner box 202 on the top, back, bottom, and sides of the refrigerator 200. Although not shown, the vacuum insulation panel 10 may be disposed on an insulating door that can be opened and closed at the front opening of the refrigerator 200.

[0058] When vacuum insulation panels 10, 20 are installed horizontally, the lower part of core material 406 arranged in the reduced pressure space is compressed in the thickness direction by its own weight. On the other hand, when vacuum insulation panels 10, 20 are installed vertically, core material 406 is not compressed in the thickness direction by its own weight. Therefore, when vacuum insulation panels 10, 20 are installed vertically, the contact area between core material 406 and the sheet is reduced due to compression by its own weight, which is thought to improve insulation performance. Therefore, by making the total area of ​​vacuum insulation panels 10, 20 installed approximately vertically, which provides high insulation performance, larger than the total area of ​​vacuum insulation panels 10, 20 installed approximately horizontally, a refrigerator 200 can be obtained that is highly effective relative to the cost of parts.

[0059] FIG. 13 is an enlarged cross-sectional view of region B in FIG. 12. Surface 2010 of outer box 201 and surface 2020 of inner box 202 of refrigerator 200 have minute irregularities. Vacuum insulation panel 10 is bonded to the surface of outer box 201 and / or inner box 202 with adhesive 203. Adhesive 203 is a foam adhesive that foams when mixed with an inert gas such as nitrogen gas, such as Foammelt (registered trademark). If outer box 201 or inner box 202 is made of a hard material such as resin or metal, the surface may have irregularities. These irregularities can create gaps between vacuum insulation panel 10, 20 and surface 2010 or 2020, potentially causing condensation. Using a foam adhesive as adhesive 203 can fill the gaps and bond the panels together, thereby suppressing condensation.

[0060] Although the vacuum insulation panels 10, 20 are described as being installed substantially horizontally in the refrigerator 200, they can be similarly bonded when installed substantially vertically or at an angle. It is not necessary to bond both sides of the vacuum insulation panels 10, 20; only one side may be bonded. While the present embodiment describes an example in which the vacuum insulation panels 10, 20 are bonded to the outer box 201 and / or inner box 202, the same method can be applied to other components of the refrigerator 200. [Explanation of symbols]

[0061] 10, 20... Vacuum insulation panel, 101, 301... Film, 102, 302... Coating, 103, 303... Heat insulating sheet, 304... Air pocket (void), 106, 306, 406... Core material, 402... Outer case, 405... Outer packaging material, 409... Adsorbent, 200... Refrigerator, 201... Outer box, 202... Inner box

Claims

1. a core material including a laminated insulation sheet; and an outer wrapping material that seals the core material under reduced pressure, The core material does not have a spacer sheet having a porosity higher than that of the heat insulating sheet, or has the spacer sheets in less than half the number of layers of the core material. A vacuum insulation panel characterized by:

2. The heat insulating sheet is formed into a film shape, The spacer sheet is formed in a mesh shape.

2. The vacuum insulation panel according to claim 1.

3. 3. The vacuum insulation panel according to claim 2, wherein the heat insulating sheet is a resin film having a gas permeability of 10,000 L / (m^2-s) or less.

4. The heat insulating sheet accounts for the majority of the number of layers in both one half and the other half of the core material in the thickness direction.

2. The vacuum insulation panel according to claim 1.

5. The difference in the number of layers of the heat insulating sheet between one half and the other half in the thickness direction of the core material is 20% or less of the total number of layers of the core material.

5. The vacuum insulation panel according to claim 4.

6. The heat insulating sheet has a textured surface on one or both sides thereof.

2. The vacuum insulation panel according to claim 1.

7. The vacuum insulation panel is The outer case is disposed between the core material and the outer material and has a communication between the inside and outside.

2. The vacuum insulation panel according to claim 1.

8. The core has at least one hole extending in the thickness direction thereof, The pores contain an adsorbent.

7. The vacuum insulation panel according to claim 1, wherein the vacuum insulation panel is a heat insulating panel.

9. The hole extends from one end of the core material in the thickness direction to the other end.

9. The vacuum insulation panel according to claim 8.

10. An appliance comprising the vacuum insulation panel according to any one of claims 1 to 4, The device comprises: A plurality of the vacuum insulation panels is provided, The area of ​​the vacuum insulation panels installed in the equipment that are installed substantially vertically is larger than the area of ​​the vacuum insulation panels installed substantially horizontally. A device characterized by:

11. An appliance comprising the vacuum insulation panel according to any one of claims 1 to 7, The device includes a member having an uneven surface, The vacuum insulation panel and the member are bonded together with a foam adhesive. A device characterized by:

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