JP2017003183A - Heat insulation box body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator which includes a vacuum heat insulation panel and a foam insulation material in a heat insulation space of a cabinet, makes a cavity, which is not filled with the foam insulation material, less likely to occur, and achieves excellent manufacturability.SOLUTION: A heat insulation box body includes: an inner box 3 having a left side surface 3a, a right side surface 3b, an upper surface 3c, a bottom surface 3d, and a back surface 3e; an outer box which is provided at the outer side of the inner box 3 and forms a heat insulation space with the inner box 3; and a foam insulation material provided in the heat insulation space. Gas drainage holes 3e-1, which discharge a gas when the heat insulation space is filled with the foam insulation material, are provided on at least one of the left side surface 3a, the right side surface 3b, the upper surface 3c, the bottom surface 3d, and the back surface 3e of the inner box 3. Air permeable sheets 32a, 32b, 34 are bonded to heat insulation space sides of surfaces of the inner box 3 which do not have the gas drainage holes 3e-1.SELECTED DRAWING: Figure 3

Description

  Embodiment of this invention is related with a heat insulation box.

  Conventionally, a heat insulating box such as a refrigerator is configured by filling a heat insulating space formed between an outer box and an inner box with a foam heat insulating material, and a storage space is formed therein. In such a heat insulation box, the wall thickness that partitions the storage space by replacing a part of the foam insulation filled between the outer box and the inner box with a vacuum insulation better in insulation performance than the foam insulation. However, there is a problem that the rigidity is lowered as the wall thickness of the heat insulating box is reduced. In response to this, various measures have been taken, such as adopting highly rigid vacuum heat insulating materials, mixing glass fibers in foam heat insulating materials, and installing reinforcing plates in each part of the outer box. Yes.

JP 2008-101791 A

  The problem to be solved by the present invention is to provide a heat insulating box that can solve the decrease in rigidity of the inner box due to the thinning of the wall.

  The heat insulation box of this embodiment includes an inner box having a left side surface, a right side surface, an upper surface, a bottom surface, and a back surface, and an outer box that is provided outside the inner box and forms a heat insulation space between the inner box and the inner box. And a foam heat insulating material provided in the heat insulating space, and a gas that exhausts gas when filling the foam heat insulating material on at least one of the left side surface, the right side surface, the top surface, the bottom surface, and the back surface of the inner box It is a heat insulation box provided with a vent hole, and a breathable sheet is stuck on the heat insulation space side of the surface of the inner box that does not have the gas vent hole.

It is sectional drawing of the heat insulation box which concerns on one Embodiment of this invention. It is AA sectional drawing of FIG. It is the perspective view which looked at the inner box from the back. It is a disassembled perspective view of a heat insulation box. It is a figure which shows the spreading state of the foaming undiluted | stock solution of a foam heat insulating material.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The heat insulation box 1 according to the present embodiment has a box shape that opens to the front surface provided with a left side wall, a right side wall, a ceiling wall, a bottom wall, and a back wall, and cools a storage room partitioned inside the box. A door that closes the front opening together with the refrigeration cycle is provided to constitute a refrigerator.

  The heat insulation box 1 forms a heat insulating space 4 between an outer box 2 made of steel plate and an inner box 3 made of synthetic resin, and a foam heat insulating material 20 such as urethane foam or a vacuum heat insulating panel 22 is formed in the heat insulating space 4. Is provided. A plurality of storage rooms are provided inside the inner box 3. Specifically, as shown in FIG. 1, a refrigeration room 6 and a vegetable room 7 are provided in order from the top, and an ice making room is provided below the storage room 6. 8 and a small freezer compartment 9 are provided side by side, and a freezer compartment 10 is provided below them.

  The refrigerator compartment 6 and the vegetable compartment 7 are both storage compartments cooled to a refrigeration temperature zone (for example, 1 to 4 ° C.), and the space between them is partitioned up and down by a partition plate 11 made of synthetic resin. .

  Below the vegetable compartment 7 is partitioned by a heat insulating partition wall 12 provided with a heat insulating material inside, and a refrigerated space cooled to a refrigeration temperature zone (for example, −10 to −20 ° C.) is formed. This freezing space is partitioned vertically by a partition plate 13, and the upper space is further divided into left and right by a partition plate 14 to provide an ice making chamber 8 and a small freezing chamber 9, and a freezing chamber 10 is provided below the partition plate 13. It has been.

  The outer box 2 constituting the outer shell of the heat insulating box 1 has a box shape opened to the front surface having the left side surface 2a, the right side surface 2b, the top surface 2c, the bottom surface 2d and the back surface 2e. The left side surface 2a, the right side surface 2b, and the top surface 2c are formed by bending a single long steel plate into a substantially U shape. The bottom surface 2d and the back surface 2e are members in which steel plates provided separately from the left side surface 2a, the right side surface 2b, and the top surface 2c are formed into a predetermined shape. The bottom surface 2d is a compression that forms part of the refrigeration cycle. A step 2d-1 is formed to form a machine room 15 in which a machine and a condenser are accommodated (see FIGS. 4 and 5).

  As shown in FIG. 2, flange portions 2a-1 and 2b-1 projecting inward in the width direction are formed at the front end portions of the left side surface 2a and the right side surface 2b, and the rear ends of the left side surface 2a and the right side surface 2b. The part is formed with flanges 2a-2 and 2b-2 which are directed forward. Furthermore, flange portions 2e-1 and 2e-2 that are inserted and engaged with the flange portions 2a-2 and 2b-2 of the left side surface 2a and the right side surface 2b are formed at the left and right ends of the back surface 2e.

  On the heat insulation space 4 side of the left side surface 2a, right side surface 2b, top surface 2c, bottom surface 2d and back surface 2e of the outer box 2, a flat vacuum heat insulation panel 22 is formed with an adhesive such as a thermoplastic adhesive (hot melt). The vacuum heat insulation panel 22 is arrange | positioned in the heat insulation space 4 formed by sticking and the inner box 3 by this.

  Further, as shown in FIGS. 2 and 4, injection holes 16 for injecting the foaming stock solution P of the foam heat insulating material 20 into the heat insulating space 4 are formed in the left and right sides of the back surface 2 e as shown in FIGS. 2 and 4. Has been.

  The inner box 3 is formed by molding a synthetic resin material with a vacuum molding machine. The left side surface 3a and the right side surface 3b are respectively opposed to the left side surface 2a, the right side surface 2b, the top surface 2c, the bottom surface 2d, and the back surface 2e of the outer box 2. A box shape is formed in the front surface having the top surface 3c, the bottom surface 3d, and the back surface 3e, and the heat insulating space 4 is formed between the outer box 2 and the outer surface 2.

  The heat insulating space 4 formed by the outer box 2 and the inner box 3 is provided with a vacuum heat insulating panel 22 affixed to the outer box 2. A refrigerant pipe (not shown) such as a heat radiating pipe is provided. In the present embodiment, a foam heat insulating material 20 is provided between the vacuum heat insulating panel 22 affixed to the outer box 2 and the left side surface 3a, right side surface 3b, top surface 3c, bottom surface 3d and back surface 3e of the inner box 3. The outer box 2 and the inner box 3 are integrated by the foam heat insulating material 20.

  A bead 17 is provided on the left side surface 3a and the right side surface 3b of the inner box 3 so as to project into the storage chambers 6, 7, 8, 9, and 10. As shown in FIG. 1, the bead 17 has a ridge shape extending in the front-rear direction provided at a position where the left and right side surfaces 3a and 3b face each other, and supports a shelf plate and a drawer container (not shown).

  At the front end portions of the left side surface 3a and the right side surface 3b of the inner box 3, flange portions 3a-1, which are inserted and engaged with the flange portions 2a-1, 2b-1 of the left side surface 2a and the right side surface 2b of the outer case 2, 3b-1 is formed.

  On the back surface 3 e of the inner box 3, a partition portion 3 f that forms the heat insulating partition wall 12 protrudes toward the front opening of the inner box 3. As shown in FIG. 3, the partition portion 3f opens on the left side surface 3a, the right side surface 3b, and the back surface 3e of the inner box 3, and is formed between the outer box 2 and the inner box 3 through this opening. The heat insulating space 4 communicates with the inside of the heat insulating partition wall 12.

  Further, the back surface 3e of the inner box 3 is provided with a gas vent hole 3e-1 penetrating from the storage chamber to the heat insulation space, and when the heat insulation space 4 is filled with the foam heat insulating material 20, the air in the heat insulation space 4 is discharged. The gas is discharged to the outside through the vent hole 3e-1. In this example, a plurality of gas vent holes 3e-1 are provided in the left and right sides of the back surface 3e of the inner box 3 at intervals in the vertical direction. In the present embodiment, the vent hole 3e-1 is provided on the back surface 3e of the inner box 3, and is not provided on the left side surface 3a, the right side surface 3b, the top surface 3c, and the bottom surface 3d.

  On the bottom surface 3d of the inner box 3, a step portion 3d-1 for forming the machine room 15 corresponding to the step portion 2d-1 of the bottom surface 2d of the outer box 2 is formed.

  Further, the left side surface 3a, the right side surface 3b, the top surface 3c, and the bottom surface 3d of the inner box 3 are provided with concave grooves 18a and 18b that are recessed from the heat insulating space 4 into the storage chambers 6, 7, 8, 9, and 10, respectively. ing. The concave grooves 18a and 18b provided on the left side surface 3a and the right side surface 3b are provided linearly along the vertical direction, and the concave grooves 18a and 18b provided on the top surface 3c and the bottom surface 3d are linear along the horizontal direction. In this example, the ends of the concave grooves 18a and 18b provided on the adjacent surfaces of the inner box 3 are connected, and the concave grooves 18a and 18b are connected to the left side surface 3a, the top surface 3c, and the right side surface. 3b and the bottom surface 3d are provided in a row so as to go around. The concave grooves 18a and 18b provided around the left side surface 3a, the top surface 3c, the right side surface 3b, and the bottom surface 3d of the inner box 3 are spaced in the front-rear direction at the front and rear portions of the inner box 3. A plurality may be provided with a gap.

  As shown in FIGS. 2 and 3, the inner box 3 has a belt-like breathable sheet on the heat insulating space 4 side of the back surface 3e so as to cover the gas vent hole 3e-1 provided on the back surface 3e from the outside. 30 are attached to the left and right sides of the back surface 3e of the inner box 3 one by one. The breathable sheet 30 is provided along the vertical direction across the partition portion 3f that opens from the upper end to the lower end of the rear surface 3e, and is provided with a plurality of gas vent holes 3e-1 provided at intervals in the vertical direction. Is covered with one breathable sheet 30.

  In addition to the breathable sheet 30 covering the gas vent hole 3e-1, a plurality of breathable sheets 32a, 32b, 34, and 36 are attached to the heat insulating space 4 side of the inner box 3.

  Specifically, the air permeable sheets 32 a, 32 b, and 34 are belt-like air permeable sheets attached to the surface of the inner box 3 where the gas vent holes 3 e-1 are not provided, and constitute the inner box 3. It is provided over a plurality of surfaces.

  The breathable sheets 32a and 32b are affixed to the bottom surfaces of the concave grooves 18a and 18b provided in the inner box 3, and are provided on the left side surface 3a, the top surface 3c, the right side surface 3b, and the bottom surface 3d of the inner box 3. . In addition, in this embodiment, although the partition part 3f and the bead 17 which open to the heat insulation space 4 side of the left side surface 3a and the right side surface 3b of the inner box 3 are formed, the air permeable sheets 32a and 32b are the partition part 3f. Or the bead 17 and is provided so as to circulate without breaking the left side surface 3a, the top surface 3c, the right side surface 3b, and the bottom surface 3d of the inner box 3.

  As shown in FIG. 2, the thickness of the air permeable sheets 32a and 32b provided in the concave grooves 18a and 18b is larger than the depth of the groove 18 and the air permeable sheets 32a and 32b provided in the concave grooves 18a and 18b. Protrudes from the left side surface 3a, the top surface 3c, the right side surface 3b, and the bottom surface 3d to the heat insulating space 4 side.

  The breathable sheet 34 is a breathable sheet attached to the left and right side surfaces 3a, 3b of the inner box 3, and extends from the front portion of the inner box 3 to the rear and is provided in the recessed grooves 18a, 18b. Crosses 32a and 32b. As described above, since the air permeable sheets 32a and 32b provided in the concave grooves 18a and 18b protrude from the left and right side surfaces 3a and 3b to the heat insulating space 4 side, the air permeable sheets 34 extending along the front-rear direction are recessed. It overlaps in the contact state in the location which cross | intersects the air permeable sheets 32a and 32b provided in the grooves 18a and 18b. The rear end portion of the breathable sheet 34 is bent inward in the width direction at the rear ends of the left and right side surfaces 3a and 3b, extends to the side portion of the back surface 3e, and extends in the vertical direction to cover the gas vent hole 3e-1. Crossing 30 and overlapping in contact. A plurality of such air-permeable sheets 34 are provided at intervals in the vertical direction, and are provided in a lattice pattern with the air-permeable sheets 30 extending in the vertical direction on the left and right side surfaces 3 a and 3 b of the inner box 3. .

  The breathable sheet 36 is a belt-shaped breathable sheet affixed to the back surface 3e of the inner box 3. The two breathable sheets 36 are affixed in a diagonal line connecting diagonally opposite corners of the back surface 3e. It intersects at approximately the center and overlaps in contact.

  The breathable sheets 30, 32a, 32b, 34, and 36 affixed to the heat insulating space 4 side of the inner box 3 are not particularly limited as long as they are flexible sheet materials having breathability. A foam sheet of urethane foam or rubber, or a fiber sheet such as a nonwoven fabric or a woven fabric can be used. The thickness of the air permeable sheets 30, 32 a, 32 b, 34, 36 is such that the foaming stock solution P injected into the heat insulating space 4 can penetrate into the air permeable sheets 30, 32 a, 32 b, 34, 36. preferable.

  Further, the thickness of each of the breathable sheets 30, 32a, 32b, 34, and 36 affixed to the inner box 3 may be the same, but in the present embodiment, the thickness of the breathable sheets 32a and 32b is Different from the breathable sheets 30, 34, 36. Specifically, the breathable sheet 32a provided in the concave groove 18a is provided with the largest thickness, and the breathable sheet 32b provided in the concave groove 18b is provided in the concave groove 18a. The air-permeable sheet 30, 34, 36 provided on the back surface 3 e of the inner box 3 is provided with the thinnest wall, and is attached to a position away from the gas vent hole 3 e-1. Is provided thicker than the breathable sheet adjacent to the gas vent 3e-1.

  Here, as an example of the thickness of the breathable sheets 30, 32a, 32b, 34, and 36, when the breathable sheets 30, 32a, 32b, 34, and 36 use a sheet material made of open cell urethane foam, The thickness of the air permeable sheet 32a provided in the groove 18a is 10 mm, the thickness of the air permeable sheet 32b provided in the recessed groove 18b is 7 mm, and the air permeable sheets 30, 34 provided on the back surface 3e of the inner box 3; The thickness of 36 can be provided at 5 mm.

  Next, the manufacturing method of the heat insulation box 1 of the said structure is demonstrated based on FIG.4 and FIG.5.

  First, the vacuum heat insulating panel 22 is bonded to the heat insulating space 4 side of the left side surface 2a, right side surface 2b, top surface 2c, bottom surface 2d and back surface 2e of the outer box 2 with an adhesive such as double-sided adhesive tape or hot melt.

  Further, the breathable sheets 30, 32a, 32b, 34, and 36 are attached to the above-described predetermined positions on the heat insulating space 4 side of the inner box 3 with an adhesive such as a double-sided adhesive tape.

  Next, as shown in FIG. 4, a breathable sheet 30, 32 a, 32 b, 34, 36 is affixed to the inside of the left side surface 2 a, the right side surface 2 b and the top surface 2 c of the outer box 2 provided with the vacuum heat insulation panel 22. The box 3 is arranged, and the flange portions 3a-1a and 3b-1a of the left side surface 3a and the right side surface 3b of the inner box 3 are connected to the flange portions 2a-1 and 2b-1 of the left side surface 2a and the right side surface 2b of the outer case 2. To be inserted and engaged.

  And in the heat insulation space 4 formed between the outer box 2 and the inner box 3, it was provided in the heat insulation box 1 or the refrigerant pipe such as a heat radiation pipe constituting the refrigeration cycle in a place where the vacuum heat insulation panel 22 does not exist. After arranging the lead wires extending from the electrical components, the bottom surface 2d of the outer box 2 is attached to the left side surface 2a and the right side surface 2b of the outer case 2, and the back surface 2e of the outer case 2 is further connected to the left side surface 2a, the right side surface 2b, Attach to the bottom 2d.

  Then, as shown in FIG. 5, with a foaming jig (not shown) fitted in the inner box 3 with the front openings of the outer box 2 and the inner box 3 facing downward, The injection nozzle 24 is inserted into the provided injection hole 16, and the foaming stock solution P of the foam insulation 20 discharged from the injection nozzle 24 is injected into the heat insulation space 4 through the injection hole 16.

  After the foaming stock solution P injected into the heat insulating space 4 from the injection hole 16 is received by the flange portions 2a-1, 2b-1, 3a-1, 3b-1 of the front opening portions of the outer box 2 and the inner box 3. The inside of the left side wall, the right side wall, the ceiling wall, and the bottom wall of the heat insulation box 1 is expanded by foaming, and the inside of the heat insulation box 1 is filled from the front side to the rear side. It goes around and flows into the back wall of the heat insulation box 1 and fills the back wall. At the time of filling with the foam heat insulating material 20, the foaming stock solution P is immersed in the air permeable sheets 30, 32 a, 32 b, 34, 36 attached to the heat insulating space 4 side of the inner box 3, and the air permeable sheets 30, 32a, 32b, 34, and 36 are impregnated and hardened to form a strong resin layer having a high density.

  And when the foam insulation 20 is filled in the whole heat insulation space 4, the heat insulation box body in which the vacuum insulation panel 22 fixed to the heat insulation space 4 side of the outer box 2 is bonded and fixed to the inner box 3 by the foam insulation 20 1 is obtained.

  In the heat insulation box 1 of this embodiment as described above, not only the back surface 3e of the inner box 3 where the gas vent holes 3e-1 are provided, but also the surfaces 3a, 3b where the gas vent holes 3e-1 are not provided. Since the air permeable sheets 32a, 32b, and 34 are also affixed to 3c and 3d, these air permeable sheets 32a, 32b, and 34 are also impregnated and cured by the foam heat insulating material 20, and the entire inner box 3 can be reinforced. The rigidity of the box 1 can be improved.

  In the present embodiment, the breathable sheet 34 extending in the front-rear direction intersects with the breathable sheet 32 and the breathable sheet 30 extending in the up-down direction, or the breathable sheet 36 is pasted diagonally to the back surface 3e. Since the air-permeable sheet is provided so as to overlap a part of another air-permeable sheet, the overlapping air-permeable sheets are impregnated and cured by the foam heat insulating material 20. Thus, the inner box 3 can be reinforced while supporting each other, and the rigidity of the inner box 3 can be improved.

  In the present embodiment, since the breathable sheets 34 and 36 are provided over a plurality of surfaces of the inner box 3, the breathable sheet impregnated and hardened by the foam heat insulating material 20 is arranged three-dimensionally to twist the inner box 3. The distortion between the surfaces can be suppressed, and the rigidity of the inner box 3 can be further improved.

  In the present embodiment, the breathable sheet 34 is affixed to the inner box 3 so as to straddle the beads 17 provided on the left side surface 3 a and the right side surface 3 b of the inner box 3, and the breathable sheet 34 is located at the position of the bead 17. It is not necessary to cut and stick to the inner box 3 and the workability is excellent.

  In the present embodiment, since the air permeable sheet 34 is provided in the concave grooves 18a and 18b provided in the inner box 3, the inner box 3 can be reinforced by the concave grooves 18a and 18b, and the ventilation to the inner box 3 can be performed. Positioning of the adhesive sheet 34 is facilitated.

  Moreover, in this embodiment, the air permeable sheet 32a provided in the concave groove 18a is provided with the largest thickness, and the air permeable sheet 32b provided in the concave groove 18b is provided in the concave groove 18a. The breathable sheets 30, 34, and 36 provided on the back surface of the inner box 3 are thinner than the sheet 32 a, and the thickness of the breathable sheet varies depending on the position to be attached to the inner box 3. ing. Since the foaming stock solution P injected from the injection hole 16 of the outer box 2 is foamed and filled in order from the front side to the back side of the heat insulating space 4, foaming starts in the breathable sheet 32a provided in the concave groove 18a. It is located in the front part of the heat insulating space 4 to be filled immediately after, and the foaming pressure of the foaming stock solution P is relatively high, and the foaming stock solution P is easily impregnated into the breathable sheet 32a, but is provided on the back surface 3e of the inner box 3. Since the air-permeable sheets 30, 34, and 36 are positioned at the end of foam filling, the foaming pressure of the foaming stock solution P is relatively low, and the foaming stock solution P is difficult to be impregnated into the air-permeable sheets 30, 34, and 36.

  Therefore, by providing a thick air-permeable sheet 32a provided in the concave groove 18a, a strong and thick resin layer is provided in the heat insulating space 4 to increase the reinforcing performance on the front side of the inner box 3, and the inner box If the breathable sheets 30, 34, and 36 affixed to the back surface 3e of No. 3 are thick, the foaming stock solution P may not penetrate into the deep portion of the breathable sheet and the breathable sheet may not be impregnated and cured. Thus, by providing a thinner air-permeable sheet attached to a position where the foaming pressure of the foaming stock solution P is lower in the heat insulating space 4, all the air-permeable sheets attached to the inner box 3 can be reliably impregnated and cured.

  In the above-described embodiment, the belt-like breathable sheets 30, 32 a, 32 b, 34, and 36 are attached to the inner box 3, and the breathable sheets 30, 32 a, 32 b, 34, and 36 are provided on a part of the inner box 3. As described above, a breathable sheet may be provided on the entire surface of the inner box 3 on the heat insulating space 4 side, whereby the entire inner box 3 can be reinforced with a breathable sheet impregnated and cured with the foaming stock solution P. The rigidity of the body 1 can be improved.

  As mentioned above, although embodiment of this invention was described, these embodiment was shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 1 ... Thermal insulation box body, 2 ... Outer box, 3 ... Inner box, 3e-1 ... Gas vent hole, 3f ... Partition part, 4 ... Thermal insulation space, 15 ... Machine room, 17 ... Bead, 18a ... Concave groove, 18b ... Groove, 20 ... Foam insulation, 30 ... Breathable sheet, 32a ... Breathable sheet, 32b ... Breathable sheet, 34 ... Breathable sheet, 36 ... Breathable sheet, P ... Foam stock solution

Claims (8)

An inner box having a left side surface, a right side surface, a top surface, a bottom surface, and a back surface;
An outer box provided outside the inner box and forming a heat insulating space with the inner box;
A foam heat insulating material provided in the heat insulating space,
A heat-insulating box body provided with a gas vent hole for discharging gas when filling with the foam heat insulating material on at least one of the left and right side surfaces, the top surface, the bottom surface, and the back surface of the inner box,
The heat insulation box which the air permeable sheet is affixed on the heat insulation space side of the surface which does not have the said vent hole of the said inner box. An inner box having a left side surface, a right side surface, a top surface, a bottom surface, and a back surface;
An outer box provided outside the inner box and forming a heat insulating space with the inner box;
A heat insulating box provided with a foam heat insulating material provided in the heat insulating space,
A plurality of breathable sheets affixed to the heat insulating space side of the inner box,
The heat insulating box body in which at least one of the plurality of breathable sheets overlaps a part of the other breathable sheet.   The heat-insulating box according to claim 2, wherein the breathable sheet affixed across a plurality of surfaces of the inner box overlaps with a part of another breathable sheet. The inner box includes a bead that protrudes toward the storage space and extends linearly,
The heat insulation box of any one of Claims 1-3 in which the said air permeable sheet is provided so that the said bead may be straddled. The inner box includes a recessed groove recessed on the storage space side,
The heat insulating box according to any one of claims 1 to 4, wherein the breathable sheet is provided in the concave groove.   The heat insulating box body according to any one of claims 1 to 5, wherein a plurality of types of the breathable sheets having different thicknesses are attached to the heat insulating space side of the inner box.   The heat insulation box body of any one of Claims 1-6 by which the said air permeable sheet is stuck so that the heat insulation space side whole surface of the said inner box may be covered.   The heat insulating box according to any one of claims 1 to 7, wherein the breathable sheet is made of urethane foam having an open cell structure.

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