Heat insulation wall and heat insulation container

Abstract

To provide a heat insulation wall that can achieve both strength and heat insulation performance.SOLUTION: A heat insulation wall 20 comprises: a core material 30 made of urethane foam comprising a plurality of cells 40; and an outer cover material 21 comprising an internal space housing the core material 30, and in which the internal space is depressurized. The core material 30 comprises: a skin layer 36 including a surface 31 in contact with the outer cover material 21; and an inner layer located at a position more distant from the outer cover material than the skin layer 36, and including the plurality of cells. The plurality of cells 40 included in the inner layer comprise first cells 41 opened in the surface 31 through the skin layer 36, and second cells 42 not opened in the surface 31.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to insulating walls and insulating containers. [Background technology]

[0002] A conventionally known example of a heat-insulating wall is the heat-insulating box described in Patent Document 1. This heat-insulating box is described as being formed by filling the hollow part of a case with urethane foam and evacuating the hollow part to create a vacuum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-119771 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the hollow part of the case is filled with urethane foam as in the case of the heat-insulating box of Patent Document 1, an airtight skin layer is formed on the surface of the urethane foam that contacts the inner surface of the case. Since the urethane foam is covered by this skin layer, the inside of the urethane foam cannot be made into a vacuum even if the inside of the hollow part is evacuated, and the heat insulation of the heat-insulating box cannot be improved. In addition, the heat-insulating box contains many air bubbles in the urethane foam, so it is easily deformed due to the air bubbles.

[0005] The present disclosure has been made to solve such problems, and has an object to provide an insulating wall and an insulating container that can achieve both thermal insulation properties and strength. [Means for solving the problem]

[0006] An insulating wall according to one embodiment of the present disclosure comprises a core material made of urethane foam having a plurality of cells, and an outer covering material having an internal space to accommodate the core material, the internal space being reduced in pressure, the core material having a skin layer including a surface that contacts the outer covering material, and an inner layer located farther from the outer covering material than the skin layer and including a plurality of the cells, the plurality of cells included in the inner layer having a first cell that opens to the surface through the skin layer, and a second cell that does not open to the surface.

[0007] According to this configuration, the cells of the core material communicate with the outside of the core material through the first cells that open to the surface. By venting the cells of the core material to the outside through these first cells, the heat insulating properties of the insulating wall can be improved. In addition, the skin layer covering the second cells is stretched, so that the strength required to suppress deformation of the insulating wall can be ensured. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide an insulating wall and an insulating container that are capable of achieving both strength and thermal insulation properties. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of an insulating container having an insulating wall according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing the core and skin of the insulating wall of FIG. [Diagram 3] FIG. 3 is a perspective view showing the core material of FIG. [Figure 4] FIG. 4 is a cross-sectional view of the insulating wall of FIG. [Diagram 5] Figure 5(a) is a scanning electron microscope (SEM) image of the core material taken by cutting the first layer at a cross section perpendicular to the thickness direction and photographing the skin layer with an SEM. Figure 5(b) is a SEM image of the core material taken by cutting the skin layer and the first layer at a cross section parallel to the thickness direction and photographing the skin layer and the first layer with an SEM. [Figure 6]Figure 6(a) is an enlarged image of the area enclosed by the dotted line frame in the SEM image of Figure 5(b). Figure 6(b) is an enlarged image of the area enclosed by the dotted line frame in the SEM image of Figure 6(a). [Figure 7] 7(a) and 7(b) are SEM images of the core material, in which planar partition walls having communicating holes are photographed using a scanning electron microscope. [Figure 8] FIG. 8 is an SEM image of the core material taken with a scanning electron microscope after cutting the skin layer, the first layer, and the second layer in a cross section parallel to the thickness direction. [Figure 9] Fig. 9(a) is a perspective view showing a schematic diagram of a flattened cell having a flattened ellipsoid shape, and Fig. 9(b) is a cross-sectional view of the third cell shown in Fig. 9(a) cut along the minor axis, the first major axis, and the second major axis. [Figure 10] FIG. 10 is a diagram that illustrates the relationship between the minor axis of the third cell in FIG. 9(a) and the thickness direction of the core material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding elements are denoted by the same reference numerals throughout the drawings.

[0011] The insulated container 10 according to the present disclosure is, for example, box-shaped with an open top surface 11, and has an inner surface 15, an outer surface 16, and a container space 14 which is an internal space. The inner surface 15 surrounds the periphery of the container space 14, and the outer surface 16 surrounds the periphery of the inner surface 15. The upper surface 11 is connected to the outer periphery of the inner surface 15 and the outer periphery of the outer surface 16.

[0012] The insulated container 10 includes an insulating wall 20. In the example of FIG. 1, the insulating wall 20 has the same shape and size as the insulated container 10, and the insulated container 10 is formed by one insulating wall 20. In this case, the insulating wall 20 is synonymous with the insulated container 10. The shape of the insulating wall 20 and the number of insulating walls 20 forming the insulated container 10 are not limited to this. For example, the insulating wall 20 may be in the shape of a flat plate. In this case, the insulated container 10 may be formed by a plurality of insulating walls 20 (for example, five).

[0013] As shown in the example of FIG. 2, the insulating wall 20 includes a core material 30 made of urethane foam having cells 40 (FIG. 4), and an outer cover material 21 having an insulating space 22, which is an internal space for accommodating the core material 30, and in which the insulating space 22 is decompressed. The core material 30 is a porous body containing a large number of cells 40 (FIG. 4), and serves as the skeleton of the insulating wall 20. The cells 40 are air bubbles (small spaces) formed by foaming in the urethane. For example, the core material 30 is made of urethane resin and is a hard urethane foam. Details of the core material 30 will be described later.

[0014] The outer covering material 21 has gas barrier properties and maintains the pressure in the heat-insulating space 22 lower than atmospheric pressure. For example, the outer covering material 21 may be a laminate film including a heat-weldable thermoplastic resin layer, an air barrier layer such as an ethylene-vinyl alcohol copolymer or a polyvinyl alcohol polymer, and a water vapor barrier layer such as polypropylene. The outer covering material 21 may also be a laminate film having a metal foil or a resin film on which a metal is vapor-deposited as a gas barrier layer.

[0015] The outer covering material 21 accommodates the core material 30 in its insulating space 22, and covers and seals the surface 31 of the core material 30. Note that in addition to the core material 30, a gas adsorbent may be accommodated in the insulating space 22 of the outer covering material 21. The gas adsorbent adsorbs gases such as water vapor and air that remain in or enter the insulating space 22 of the outer covering material 21. This makes it possible to maintain the pressure in the insulating space 22 of the outer covering material 21 low.

[0016] <Insulated wall manufacturing method> 2, the insulating wall 20 has a core material 30 and an outer covering material 21, and the outer covering material 21 has an inner member 23 and an outer member 24. The inner member 23 and the outer member 24 each have a box shape with an open top, and are provided with flange portions 23a, 24a surrounding the periphery of the opening. The inner member 23 and the outer member 24 are each formed into a predetermined shape by vacuum forming, pressure forming, blow molding, or the like.

[0017] Furthermore, the mold for the core material 30 is heated to a predetermined temperature higher than room temperature (e.g., 20°C±15°C), e.g., 50°C or higher, and the urethane liquid is poured into the heated mold. The urethane liquid contains a compound having a hydroxyl group such as polyol, polyisocyanate, and a chemical foaming agent such as water. Note that the urethane liquid may further contain a physical foaming agent such as hydrofluoroolefin when control of the filling property and reaction temperature is required.

[0018] In the mold, the polyol and polyisocyanate in the urethane liquid undergo a polymerization reaction, and the heat generated by this polymerization reaction heats the blowing agent, causing it to foam, forming multiple cells 40 in the urethane. The urethane foam thus formed is then released from the mold, and a box-shaped core material 30 with an open top is formed. The surface 31 of this core material 30 is the surface that was in contact with the mold.

[0019] Then, the core material 30 is accommodated in the outer member 24, and the inner member 23 is accommodated in the core material 30. As a result, the core material 30 is accommodated in the insulating space 22 between the outer member 24 and the inner member 23, and the flange portion 23a of the inner member 23 overlaps on the flange portion 24a of the outer member 24. The flange portion 24a and the flange portion 23a are welded together, and the insulating space 22 is evacuated from an opening provided in either the inner member 23 or the outer member 24. As a result, the insulating space 22 is depressurized, and the inner member 23 and the outer member 24 are in close contact with the surface 31 of the core material 30. Then, the opening is sealed with a sealant to seal the outer covering material 21. As a result, the insulating wall 20 in which the pressure in the insulating space 22 is lower than atmospheric pressure is manufactured. In this case, the inner member 23 forms the inner surface 15 (FIG. 1) of the insulating wall 20, and the outer member 24 forms the outer surface 16 (FIG. 1) of the insulating wall 20.

[0020] <Core material> As shown in the example of FIG. 3, the core material 30 of the heat insulating wall 20 is box-shaped with an open top and has five flat surfaces 32 and corners 33. Of the five flat surfaces 32, four flat surfaces 32 form the side surfaces of a cylinder whose top and bottom surfaces are open, and the remaining flat surface 32 covers the opening on the bottom surface. In such a box-shaped core material 30, the corners 33 are provided linearly at positions where two flat surfaces 32 are connected. For example, the corners 33 are provided at the connection parts between the flat surface 32 forming the bottom surface and the flat surface 32 forming the side surface. In addition, the corners 33 are provided at the connection parts of the flat surfaces 32 forming each of the two side surfaces.

[0021] 4, the core material 30 has a skin layer 36 and an inner layer 38. The outer surface of the skin layer 36 faces and contacts the outer covering material 21, forming a surface 31 of the core material 30. The surface 31 is flat and extends in a direction perpendicular to the thickness direction.

[0022] The inner layer 38 is located farther from the outer covering material 21 than the skin layer 36 in the thickness direction perpendicular to the surface 31. A plurality of cells 40 are dispersed in the inner layer 38 in the thickness direction and the perpendicular direction. The skin layer 36 is provided between the cells 40 of the inner layer 38 and the outside of the core material 30, and covers the cells 40.

[0023] In the inner layer 38, planar partition walls 34 made of resin are provided between two adjacent cells 40. Columnar partition walls 35 made of resin are provided between three or more adjacent cells 40. The planar partition walls 34 have a film shape, and the dimensions of the planar partition walls 34 between the cells 40 are smaller than the dimensions of the columnar partition walls 35 between the cells 40, and are, for example, 2 μm or more and 20 μm or less. The cells 40 are in communication with each other via communication holes 43.

[0024] <Skin layer> As shown in the examples of Figures 4 and 5(a), the skin layer 36 spreads in the perpendicular direction and covers the multiple cells 40 distributed in the perpendicular direction. Also, as shown in the examples of Figures 4 and 5(b), the skin layer 36 covers the cells 40 closest to the surface 31 among the multiple cells 40 distributed in the thickness direction. The thickness L1 of the skin layer 36 is 20 µm or less, for example, 2 µm or more and 20 µm or less.

[0025] As shown in the examples of Figures 4 and 5(a), the cells 40 covered by the skin layer 36 include a first cell 41 and a second cell 42. This second cell 42 does not have a through hole 46 penetrating the skin layer 36, and does not open to the surface 31 of the core material 30. Therefore, communication between the second cell 42 and the outside of the core material 30 is blocked by the skin layer 36, and the second cell 42 is covered by the skin layer 36. The skin layer 36 braces itself, ensuring the strength required to suppress deformation of the insulating wall 20.

[0026] The first cells 41 have through holes 46 penetrating the skin layer 36. The first cells 41 open to the surface 31 of the core material 30 through the through holes 46, and communicate with the outside of the core material 30 via the through holes 46.

[0027] Each of the first cell 41 and the second cell 42 communicates with the other cells 40 through the communication holes 43. In addition, the cells 40 other than the first cell 41 and the second cell 42 also communicate with the other cells 40 through the communication holes 43. Therefore, all or almost all of the cells 40 in the core material 30 communicate with each other through the communication holes 43. Furthermore, the first cell 41 of the cells 40 communicates with the outside of the core material 30 through the through holes 46. Therefore, all or almost all of the cells 40 in the core material 30 form an open cell structure that communicates with the outside of the core material 30 through the communication holes 43 and the through holes 46. Therefore, the heat insulating property of the insulating wall 20 can be improved by evacuating the inside of the core material 30 to reduce the pressure. In this way, the first cell 41 and the second cell 42 can achieve both heat insulating property and strength of the insulating wall 20.

[0028] In addition, in the heat insulating wall 20, as shown in FIG. 3, a plurality of flat portions 32 are connected at the corner portion 33 of the core material 30, and the plurality of flat portions 32 support each other, so that the strength of the corner portion 33 is greater than the strength of the flat portion 32. Therefore, the ratio of the number of the first cells 41 to the total number of the first cells 41 and the second cells 42 included in the unit volume of the corner portion 33 may be greater than the ratio of the number of the first cells 41 to the total number of the first cells 41 and the second cells 42 included in the unit volume of the flat portion 32. In this way, by providing a large number of the first cells 41 at the corner portion 33 where strength is structurally ensured, the exhaust efficiency is improved, and the heat insulating property of the heat insulating wall 20 can be improved. Therefore, the heat insulating property and strength of the heat insulating wall 20 can be achieved at the same time.

[0029] On the other hand, in the insulating wall 20, the ratio of the number of the second cells 42 to the total number of the first cells 41 and the second cells 42 included in a unit volume of the flat portion 32 may be greater than the ratio of the number of the second cells 42 to the total number of the first cells 41 and the second cells 42 included in a unit volume of the corner portion 33. Since a large number of the second cells 42 are provided in this flat portion 32, the skin layer 36 is taut, and the strength to suppress deformation of the insulating wall 20 can be ensured.

[0030] <Through hole, communication hole> The through holes 46 and the communicating holes 43 are formed, for example, by the following methods. In the first method, as shown in the example of FIG. 7(a), the stress of the cells 40 causes holes to form or tears in the planar partition walls 34. This forms the communicating holes 43 that penetrate the planar partition walls 34 between the cells 40. Similarly to the communicating holes 43, the through holes 46 are also formed so as to penetrate the skin layer 36 between the cells 40 and the outside of the core material 30 by causing holes to form or tears in the skin layer 36 due to the stress of the cells 40.

[0031] In the second method, as shown in the example of Fig. 7(b), a mixture of polyols with different compositions is used as a compound having a hydroxyl group in a urethane liquid during the production of the core material 30. In this case, molecular level distortion occurs due to the difference in composition of the multiple polyols, and this distortion damages the planar partition walls 34, forming communicating holes 43 that penetrate the planar partition walls 34. Similarly to the communicating holes 43, the skin layer 36 is damaged by molecular level distortion, and the through holes 46 are also formed so as to penetrate the skin layer 36.

[0032] In the third method, through holes 46 are formed in corners 33 of core material 30. That is, as shown in the example of Fig. 3, corners 33 of core material 30 made of urethane foam released from a mold have parting lines along which the mold is divided, and burrs 37 may be formed on surface 31 of core material 30 along these parting lines. In this case, when burrs 37 are scraped off with a file or the like, skin layer 36 constituting surface 31 of core material 30 is damaged, and through holes 46 penetrating skin layer 36 are formed, as shown in the example of Fig. 4.

[0033] In this way, the through holes 46 and the communicating holes 43 are formed in the core material 30 by one or more methods. The cells 40 in the core material 30 communicate with the outside of the core material 30 by the through holes 46 and the communicating holes 43. Therefore, the air in the cells 40 is exhausted to the outside of the core material 30 through the through holes 46 and the communicating holes 43, thereby reducing the pressure inside the core material 30, reducing heat conduction by the air, and improving the thermal insulation of the insulating wall 20.

[0034] Furthermore, for example, by heating the mold during the manufacture of the core material 30, the thickness of the planar partition walls 34 of the skin layer 36 is reduced. Therefore, the stress of the cells 40, the strain at the molecular level, and the scraping off of the burrs 37 make it easier to form the through holes 46 in the skin layer 36. Therefore, it is not necessary to add particles for forming the through holes 46 to the urethane liquid, and there is no need for a process of adding the particles, no equipment with high durability for the particles, and no increase in viscosity due to the particles. Therefore, it is possible to improve the thermal insulation of the insulating wall 20 while suppressing the increase in cost due to the addition of particles.

[0035] <1st layer> 4 and 8, the inner layer 38 has a first layer 38a. The first layer 38a is disposed farther from the outer covering material 21 than the skin layer 36 in the thickness direction, and is laminated on the skin layer 36. The thickness L2 of the first layer 38a in the thickness direction is 5 mm or less.

[0036] The cells 40 in the first layer 38a include flattened cells 44 that are in the shape of a flattened ellipsoid. The flattened cells 44 have a flattened ellipsoid shape in which the dimension in the thickness direction is smaller than the dimension in the perpendicular direction. As shown in the example of Fig. 9(a) and Fig. 9(b), the flattened cells 44 have three axes, a minor axis, a first major axis, and a second major axis. The minor axis, the first major axis, and the second major axis are mutually perpendicular. The flattened cells 44 have a shape of a body of revolution with the minor axis as the axis of rotation.

[0037] In the flat cell 44, the dimension M0 along the minor axis is shorter than the dimension M1 along the first major axis and the dimension M2 along the second major axis. In addition, in the flat cell 44, the dimension M1 along the first major axis and the dimension M2 along the second major axis are equal to each other or approximately equal to each other. Therefore, the cross section of the flat cell 44 perpendicular to the minor axis has a circular or approximately circular shape. The cross section of the flat cell 44 with respect to the first major axis has an elliptical or approximately elliptical shape. The cross section of the flat cell 44 with respect to the second major axis has an elliptical or approximately elliptical shape.

[0038] 10, the angle θ1 between the thickness direction of the core material 30 and the short axis of the flat cell 44 is smaller than the angle θ2 between the orthogonal direction of the core material 30 and the short axis of the flat cell 44. For this reason, the flat cells 44 are arranged in the first layer 38a of the core material 30 such that the dimension N0 in the thickness direction of the core material 30 is smaller than the dimension N1 in the orthogonal direction. This increases the number of flat cells 44 in the thickness direction, which lengthens the heat transfer path of the insulating wall 20 in the thickness direction, thereby improving the thermal insulation of the insulating wall 20.

[0039] For example, by heating the mold during the manufacture of the core material 30, the dimension of the flat cells 44 in the orthogonal direction becomes larger than the dimension in the thickness direction. As a result, the planar partitions 34 between the flat cells 44 adjacent to each other in the orthogonal direction are broken, and the communication holes 43 through which the flat cells 44 communicate with each other are easily formed. Therefore, at least one of the number and the area of ​​the communication holes 43 is increased by the flat cells 44. In addition, some or all of the flat cells 44 in the core material 30 communicate with the outside of the core material 30 through other cells 40, through holes 46, communication holes 43, etc. Therefore, the efficiency of exhausting from the cells 40 of the core material 30 to the outside of the core material 30 is good, and the heat insulation of the insulating wall 20 can be improved.

[0040] In addition, the flat cells 44 cause the thermal conductivity of the insulating wall 20 to be smaller in the thickness direction than in the orthogonal direction. Therefore, the amount of heat transferred per unit time and unit area in the insulating wall 20 is smaller in the thickness direction than in the orthogonal direction. This keeps the amount of heat transferred from the outside of the insulating container 10 through the insulating wall 20 to the internal container space 14 small, and the heat retention time in the container space 14 can be extended.

[0041] Furthermore, the thermal conductivity of the insulating wall 20 is greater in the orthogonal direction than in the thickness direction. Therefore, for example, when the container space 14 of the insulated container 10 is cooled by a coolant, the temperature is uniformed in the orthogonal direction of the coolant and the insulating wall 20. This makes it possible to prolong the uniform cooling effect of the cold insulation material and to uniformize the temperature of the container space 14 of the insulated container 10.

[0042] Furthermore, the cells 40 in the first layer 38a may have spherical cells 45, in addition to the flat cells 44 forming an oblate ellipsoid shape. Some or all of the spherical cells 45 in the core material 30 are in communication with the outside of the core material 30 via other cells 40, through holes 46, communication holes 43, etc.

[0043] In the first layer 38a, the flat cells 44 are more easily deformed and more easily broken than the spherical cells 45, so that the average number of communicating holes 43 that connect the flat cells 44 to the other cells 40 is greater than the average number of communicating holes 43 that connect the spherical cells 45 to the other cells 40. The average number of communicating holes 43 for the flat cells 44 is the quotient obtained by summing up the number of communicating holes 43 that connect each flat cell 44 to the other cells 40 for a predetermined number of flat cells 44 (2 or more), divided by the predetermined number of flat cells 44. The average number of communicating holes 43 that connect the spherical cells 45 to the other cells is the quotient obtained by summing up the number of communicating holes 43 that connect each spherical cell 45 to the other cells 40 for a predetermined number of spherical cells 45 (2 or more), divided by the predetermined number of spherical cells 45. In this way, the flattened cells 44 increase the number of communicating holes 43 in the core material 30, improving the efficiency of exhaust from the cells 40 of the core material 30 to the outside of the core material 30, and the thermal insulation properties of the insulating wall 20 can be improved.

[0044] In the first layer 38a, the flat cells 44 are more easily deformed and more easily broken than the spherical cells 45, so that the average area of ​​the communication holes 43 through which the flat cells 44 communicate with the other cells 40 is larger than the average area of ​​the communication holes 43 through which the spherical cells 45 communicate with the other cells 40. The average area of ​​the communication holes 43 through which the flat cells 44 communicate with the other cells 40 is the quotient obtained by dividing the total area of ​​the communication holes 43 through which each flat cell 44 communicates with the other cells 40 for a predetermined number of flat cells 44 (2 or more) by the predetermined number of flat cells 44. The average area of ​​the communication holes 43 through which the spherical cells 45 communicate with the other cells 40 is the quotient obtained by dividing the total area of ​​the communication holes 43 through which each spherical cell 45 communicates with the other cells 40 for a predetermined number of spherical cells 45 (2 or more) by the predetermined number of spherical cells 45. In this way, the flat cells 44 increase the area of ​​the communicating holes 43 in the core material 30, improving the efficiency of exhaust from the cells 40 of the core material 30 to the outside of the core material 30, and improving the insulating properties of the insulating wall 20.

[0045] <2nd layer> The inner layer 38 has a second layer 38b. The second layer 38b is disposed farther from the skin layer 36 in the thickness direction than the first layer 38a, and is laminated on the first layer 38a. That is, in the core material 30, the skin layer 36, the first layer 38a, and the second layer 38b are laminated in this order in the thickness direction. The cells 40 of the second layer 38b have spherical cells 45. The volume of each cell 40 in the second layer 38b is larger than the volume of each cell 40 in the first layer 38a. In this way, since the cells 40 of the second layer 38b are large in size but spherical, the insulating wall 20 can achieve both thermal insulation and strength.

[0046] The cells 40 in the first layer 38a may include spherical cells 45 in addition to the flat cells 44, and the cells 40 in the second layer 38b may include flat cells 44 in addition to the spherical cells 45. In this case, the first layer 38a may be a region of the inner layer 38 in which the number of flat cells 44 per unit volume is equal to or greater than the number of spherical cells 45, and the second layer 38b may be a region of the inner layer 38 in which the number of spherical cells 45 per unit volume is equal to or greater than the number of flat cells 44. Also, the boundary between the first layer 38a and the second layer 38b in the inner layer 38 does not have to be clearly distinguishable.

[0047] (Other embodiments) (Additional Note) The above description of the embodiments discloses the following techniques. The first technology is an insulating wall comprising a core material made of urethane foam having a plurality of cells, and an outer covering material having an internal space for accommodating the core material, the internal space being reduced in pressure, the core material having a skin layer including a surface that contacts the outer covering material, and an inner layer that is positioned farther from the outer covering material than the skin layer and includes a plurality of the cells, the plurality of cells included in the inner layer having first cells that open to the surface through the skin layer, and second cells that do not open to the surface.

[0048] According to this configuration, the cells of the core material communicate with the outside of the core material through the first cells that open to the surface. By venting the cells of the core material to the outside through these first cells, the heat insulating properties of the insulating wall can be improved. In addition, the skin layer covering the second cells is stretched, so that the strength required to suppress deformation of the insulating wall can be ensured.

[0049] The second technology is the heat insulating wall according to the first technology, in which the thickness of the skin layer is 20 μm or less. With this configuration, since the thickness of the skin layer is thin, the first cell can penetrate the skin layer and open to the surface by the stress of the cell, for example, without using particles for penetrating the skin layer.

[0050] A third technology is an insulating wall described in the first or second technology, in which the inner layer of the core material has a first layer laminated to the skin layer in a thickness direction perpendicular to the surface, and the cells of the first layer include flattened cells having an oblate ellipsoid shape whose dimension in the thickness direction is smaller than the dimension in an orthogonal direction perpendicular to the thickness direction.

[0051] According to this configuration, in the case of the flattened cells forming an oblate ellipsoid shape and the spherical cells having the same volume, more flattened cells are arranged in the thickness direction than the spherical cells, which makes the heat transfer path in the thickness direction longer and improves the heat insulation of the insulating wall.

[0052] A fourth technology is the insulation wall according to the third technology, in which the thickness of the first layer is 5 mm or less. Since the compressive strength in the insulation thickness direction of the flattened cells forming the ellipsoidal shape of the first layer is lower than that of the spherical cell shape, this configuration makes it possible to maintain the strength of the entire insulation wall.

[0053] A fifth technology is an insulating wall described in the third or fourth technology, in which the cells of the first layer include, in addition to the flat cells, spherical cells that have a spherical shape, and the average area of ​​the communicating holes through which the flat cells communicate with the other cells is larger than the average area of ​​the communicating holes through which the spherical cells communicate with the other cells.

[0054] According to this configuration, the core material includes flat cells with a large average area of ​​communicating holes, which improves the efficiency of exhaust from the cells of the core material and improves the thermal insulation of the insulating wall. Also, the core material includes spherical cells with a small average area of ​​communicating holes, which ensures the strength to suppress deformation of the insulating wall.

[0055] A sixth technology is the insulating wall according to any one of the third to fifth technologies, in which the cells of the first layer include spherical cells having a spherical shape in addition to the flat cells, and the average number of communication holes connecting the flat cells to the other cells is greater than the average number of communication holes connecting the spherical cells to the other cells. According to this configuration, the core material includes flat cells with a large number of communication holes, which improves exhaust efficiency from the cells of the core material and can improve the thermal insulation of the insulating wall.

[0056] A seventh technology is the heat insulating wall according to any one of the third to sixth technologies, in which the inner layer of the core material has a second layer disposed farther from the skin layer in the thickness direction than the first layer and laminated on the first layer, and the cells of the second layer include spherical cells having a spherical shape. With this configuration, the spherical cells can ensure strength to suppress deformation of the heat insulating wall.

[0057] An eighth technology is a thermally insulated container having the thermally insulated wall according to any one of the first to seventh technologies. According to this configuration, the thermally insulated container can achieve both thermal insulation and strength by using the thermally insulated wall that has improved thermal insulation and strength.

[0058] A ninth technology is an insulated container described in the eighth technology, in which the core material has a plurality of planar portions and a corner portion to which a plurality of the planar portions are connected, and the ratio of the number of the second cells to the total number of the first cells and the second cells included in a unit volume of the planar portions is greater than the ratio of the number of the second cells to the total number of the first cells and the second cells included in a unit volume of the corner portion.

[0059] According to this configuration, the structure in which multiple flat sections are connected at the corners ensures the strength to suppress deformation of the insulated container, and the many first cells increase the exhaust efficiency and improve the insulation. Also, at the flat sections, the skin layers of the many second cells ensure the strength to suppress deformation of the insulated container.

[0060] In addition, all the above-mentioned embodiments may be combined with each other as long as they do not exclude each other. In addition, many improvements and other embodiments of the present disclosure will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as an example only, and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. The details of the structure and / or function may be substantially changed without departing from the spirit of the present disclosure. [Industrial Applicability]

[0061] The insulating wall and the insulating container of the present disclosure can be applied to an insulating wall and an insulating container that can achieve both strength and insulating properties. [Explanation of symbols]

[0062] 10: Insulated container 20: Insulated wall 21: Outer cover material 30: Core material 31 :Surface 32: Flat part 33: Corner 36: Skin layer 38: Inner layer 38a: 1st layer 38b: 2nd layer 40: Cell 41: First cell 42: Second cell 43:Communication hole 44: Flat cell 45: Spherical cell 46:Through hole

Claims

1. A core material made of a urethane foam having a plurality of cells; an outer covering material having an internal space for accommodating the core material, the internal space being decompressed; the core material has a skin layer including a surface in contact with the outer covering material, and an inner layer located farther from the outer covering material than the skin layer and including a plurality of the cells; The plurality of cells included in the inner layer include first cells that open to the surface through the skin layer, and second cells that do not open to the surface. Insulated walls.

2. The thickness of the skin layer is 20 μm or less.

2. The insulating wall of claim 1.

3. The inner layer of the core material has a first layer laminated on the skin layer in a thickness direction perpendicular to the surface, The cells of the first layer include flattened cells each having an oblate ellipsoid shape whose dimension in the thickness direction is smaller than its dimension in a direction perpendicular to the thickness direction.

2. The insulating wall of claim 1.

4. The thickness of the first layer is 5 mm or less.

4. An insulating wall according to claim 3.

5. The cells of the first layer include spherical cells having a spherical shape in addition to the flat cells, an average area of ​​communicating holes through which the flat cells communicate with the other cells is larger than an average area of ​​communicating holes through which the spherical cells communicate with the other cells; 4. An insulating wall according to claim 3.

6. The cells of the first layer include spherical cells having a spherical shape in addition to the flat cells, an average number of communicating holes between the flat cells and the other cells is greater than an average number of communicating holes between the spherical cells and the other cells; 4. An insulating wall according to claim 3.

7. the inner layer of the core material has a second layer disposed farther from the skin layer in the thickness direction than the first layer and laminated on the first layer; The cells of the second layer include spherical cells having a spherical shape.

4. An insulating wall according to claim 3.

8. A heat insulating wall according to any one of claims 1 to 7. Insulated container.

9. The core material has a plurality of planar portions and corner portions to which the planar portions are connected, a ratio of the number of the second cells to a total number of the first cells and the second cells included in a unit volume of the planar portion is greater than a ratio of the number of the second cells to a total number of the first cells and the second cells included in a unit volume of the corner portion. The insulated container according to claim 8.

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