JP6048852B2 - Vacuum insulation - Google Patents

Description

  The present disclosure relates to a vacuum heat insulating material used for a refrigerator, a cold car, and the like.

  A conventional vacuum heat insulating material is manufactured by covering a core material made of glass wool or the like with a jacket material made of a gas barrier film and sealing the inside under reduced pressure. Most of these vacuum heat insulating materials have a flat plate shape with a thickness of 3 mm to 20 mm for the convenience of manufacturing method and reliability, and are mostly applied to products such as refrigerators in the shape. . In addition, in order to improve the heat insulation characteristics of the vacuum heat insulating material, in order to suppress heat conduction and radiation, a material that does not easily transfer heat is used as the constituent material, the contact area between the materials is reduced, heat transfer It is important to control the surface direction perpendicular to the heat insulation direction.

  As an application example of the vacuum heat insulating material, a metal foil or a metal vapor deposition film excellent in the shielding effect of radiant heat, such as one in which fibers are arranged at right angles to the heat insulating direction to suppress the heat conduction amount (for example, see Patent Document 1). An embedded material (for example, see Patent Document 2), a plate-like substance such as mica that has an excellent shielding effect against radiant heat, and an integrated material such as a glass mat and a resin and laminated in a plane (for example, Patent Document) 3). In Patent Document 3, a slurry liquid in which a plate-like substance such as mica having an excellent radiant heat shielding effect is dispersed is uniformly dispersed on a glass mat to form a composite material in which the plate-like substances are laminated in the surface direction.

  Moreover, the site | part which should be insulated is not necessarily plane shape. If there are corners, protrusions or steps in the heat insulation part, the vacuum heat insulating material can be insulated by bending or punching the vacuum heat insulating material, or by shaping the exterior material in advance. A method of corresponding to the shape of a part is known. As a molding method, a powdery or granular filling is stored in a bag-like outer shell material, and the upper and lower portions of the outer shell material are compressed using a mold having a convex portion, and the inside of the outer shell material is evacuated. Vacuum the plate-shaped vacuum insulation material that is formed by reducing the pressure inside the film container filled with the heat insulating material and sealing it by heat sealing (for example, see Patent Document 4). There is one that is molded with a mold in a state where the pressure is reduced in a container, and is returned to normal pressure while being held (see, for example, Patent Document 5).

JP-A-60-208696 Japanese Patent Laid-Open No. 62-13979 Japanese Patent Laid-Open No. 10-238938 JP 61-168772 A Japanese Patent Laid-Open No. 63-163764

  However, if a metal foil or a metal vapor deposition film is simply embedded, electromagnetic waves leak and radiation increases at these discontinuous portions derived from these finite lengths. When the resin in which the plate-like substance is laminated is integrated with the core material, the conduction heat transfer becomes large, and the heat insulating properties are deteriorated. Further, the part to be insulated may have a corner. When applying a vacuum heat insulating material to a product having corners, the conventional molding method configuration requires a large apparatus because a molding die is installed in a vacuum chamber or the molding die itself is a vacuum exhaust device. There was a problem. Further, there has been a problem that the film of the outer shell material and the plate-like substance having a radiation effect are stretched at the time of molding and the reliability of the vacuum heat insulating material is lowered.

  An object of the present disclosure is to provide a vacuum heat insulating material that has a good heat insulating property and can easily form a highly reliable corner.

The vacuum heat insulating material according to the present disclosure includes a core material including an inorganic fibrous aggregate;
A jacket material covering at least one surface of the core material;
A vacuum heat insulating material whose inside is sealed under reduced pressure,
The jacket material is
The outermost resin layer,
A radiation preventing layer inside the resin layer;
The radiation prevention layer has, in part, an overlapping portion in which at least two layers of radiation prevention layers are laminated.

  Even if the vacuum insulation material is bent to provide corners, the outer shell film is stretched, and the plate-like material having a small ductility and radiation effect slips between the two layers without fail. Since they overlap, the radiation prevention effect can be secured. In addition, corners can be formed without reducing reliability.

  As described above, according to the vacuum heat insulating material of the present disclosure, it is possible to provide a vacuum heat insulating material that can easily form corner portions with good heat insulating characteristics and high reliability because the radiation preventing effect does not decrease.

3 is a cross-sectional view of the vacuum heat insulating material according to Embodiment 1. FIG. 3 is an enlarged cross-sectional view of a jacket material of the vacuum heat insulating material according to Embodiment 1. FIG. FIG. 3 is a plan view of FIG. 2. It is a cross-sectional enlarged view of the jacket material of the vacuum heat insulating material of a modification. It is a conceptual diagram of the process of bending the vacuum heat insulating material which concerns on Embodiment 1 with a metal mold | die. 1 is a conceptual cross-sectional view in which a vacuum heat insulating material according to Embodiment 1 is bent at a right angle. It is an enlarged view of the jacket material after bending the vacuum heat insulating material which concerns on Embodiment 1. FIG. 6 is an enlarged cross-sectional view of a jacket material of a vacuum heat insulating material according to Embodiment 2. FIG. It is a top view of FIG. FIG. 6 is an enlarged cross-sectional view of a jacket material of a vacuum heat insulating material according to a third embodiment. FIG. 5 is a schematic diagram when an electromagnetic wave incident on the resin layer 10 at an incident angle θ that does not totally reflect is repeatedly reflected between the upper and lower radiation prevention layers 5 and incident on the resin layer 9. It is an enlarged view of the jacket material after the bending process of the vacuum heat insulating material which concerns on Embodiment 3. FIG. It is a cross-sectional enlarged view of the jacket material of the vacuum heat insulating material which concerns on Embodiment 4. FIG. FIG. 14 is a plan view of FIG. 13. It is an enlarged view of the jacket material after the bending process of the vacuum heat insulating material which concerns on Embodiment 4. FIG.

The vacuum heat insulating material according to the first aspect includes a core material including an inorganic fibrous aggregate,
A jacket material covering at least one surface of the core material;
A vacuum heat insulating material whose inside is sealed under reduced pressure,
The jacket material is
The outermost resin layer,
A radiation preventing layer inside the resin layer;
The radiation prevention layer has, in part, an overlapping portion in which at least two layers of radiation prevention layers are laminated.

  In the vacuum heat insulating material according to the second aspect, in the first aspect, the overlapping portion may have a space between the overlapping radiation prevention layers.

  The vacuum heat insulating material according to a third aspect is the above first or second aspect, wherein the radiation preventing layer is a thin plate, and the length of the overlapping portion is between the laminated radiation preventing layers. It may be tan15 ° × (resin layer thickness) × (20− (the number of laminated resin layers + 1)) or more with respect to the thickness of the installed resin layer.

  The vacuum heat insulating material according to a fourth aspect is any one of the first to third aspects, wherein the vacuum heat insulating material has a corner, and the thickness of the vacuum heat insulating material is the bending of the corner. It may be 4 times or less of the radius.

  In the vacuum heat insulating material according to the fifth aspect, in the fourth aspect, the outermost resin layer of the jacket material may be made of a material capable of elongation of 200% or more.

  In the vacuum heat insulating material according to a sixth aspect, in any one of the first to fifth aspects, the radiation prevention layer may include a metal layer, and the thickness of the metal layer may be 40 nm or more.

  In the vacuum heat insulating material according to a seventh aspect, in the sixth aspect, the metal layer of the radiation preventing layer may be made of aluminum.

The vacuum heat insulating material according to an eighth aspect is any one of the first to seventh aspects, wherein the radiation preventing layer is
A first radiation preventing layer having a through hole;
A second radiation preventing layer that covers the through hole and forms an annular overlapping portion that is laminated with the first radiation preventing layer around the through hole;
May be included.

  Hereinafter, a vacuum heat insulating material according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a vacuum heat insulating material according to Embodiment 1 of the present invention. As shown in FIG. 1, the vacuum heat insulating material 1 includes a core material 2 and a jacket material 3 that covers the core material 2. The vacuum heat insulating material 1 is sealed under reduced pressure. The jacket material 3 is provided so as to cover both surfaces of the core material 2.
In addition, the vacuum sealing of the vacuum heat insulating material 1 should just be pressure-reduced rather than atmospheric pressure. Also, the sealing does not require strict airtightness.

  Below, the structural member which comprises this vacuum heat insulating material 1 is demonstrated.

<Core>
The core material 2 should just be an inorganic fibrous aggregate. As the core material 2, for example, glass wool, rock wool, carbon fiber, ceramic fiber, or the like can be used. In addition, the said description is an illustration and is not limited to these. Moreover, when using for a corner | angular part, what consists of the material which can be bent at the time of formation of a corner | angular part is preferable.

<Coating material>
FIG. 2 is an enlarged cross-sectional view of the jacket material 3. FIG. 3 is a plan view of FIG. The jacket material 3 has a laminated structure of an inner resin layer 4, radiation prevention layers 5-1 and 5-2, and an outermost resin layer 6. The radiation preventing layers 5-1 and 5-2 are partially overlapped at the end portions to form an overlapping portion A.
FIG. 4 is an enlarged cross-sectional view of the jacket 3 of the vacuum heat insulating material according to the modification. In this modification, the end portion 18 of the radiation preventing layer 5-1 is a tapered end portion that is tapered on the front end side, but is not limited thereto. For example, the end 18 may have a triangular shape, a wedge shape, or the like. As a result, it is possible to improve slippage during deformation of the overlapping portion A1 where the radiation preventing layer 5-1 and the radiation preventing layer 5-2 overlap.

<Radiation prevention material>
The radiation prevention layers 5-1 and 5-2 may be any layer that does not transmit electromagnetic waves and shields them. For example, an aluminum foil (plate thickness of 0.1 mm) may be used. The radiation preventing layers 5-1 and 5-2 are not limited to the aluminum foil but may be an aluminum vapor deposition film or the like. Further, any metal other than aluminum or a material having a radiation preventing function may be used. The radiation preventing layers 5-1 and 5-2 have an overlapping portion A in which two layers of the radiation preventing layers 5-1 and 5-2 (for example, aluminum foil) are overlapped over a length A range. In the overlapping part A, there is almost no gap between the radiation preventing layers 5-1 and 5-2, and therefore even if there is a slight overlapping part, the passage of electromagnetic waves that cause radiation in the thickness direction does not occur. The heat transfer mechanism in the body is roughly classified into conduction heat transfer, gas heat transfer, convection heat transfer, radiation heat transfer, and combinations thereof. In this vacuum heat insulating material 1, since the internal vacuum degree is sufficiently high, the effects of convection and gas heat transfer can be almost ignored, and only conduction heat transfer and radiation heat transfer are provided. For conduction heat transfer, if the contact area between the core material 2 and the jacket material 3 is reduced, or if a resin material having poor thermal conductivity is disposed on the contact surface with the core material 3, the effect of conduction heat transfer is reduced. Can be ignored. As for radiant heat transfer, heat transfer from the higher temperature side can be prevented by providing a substance that shields electromagnetic waves halfway. Therefore, the aluminum foil is installed on the outer side of the inner resin layer 4 as the radiation preventing layers 5-1 and 5-2. The radiation preventing layer 5-1 and the radiation preventing layer 5-2 are disposed so that the respective end portions thereof are overlapped. Aluminum is a metal excellent in ductility and workability. In general, a substance is called an absorption length, and there is a thickness that does not pass electromagnetic waves at a depth greater than that. The absorption length may be, for example, a thickness at which the electromagnetic wave intensity is attenuated to 1 / e ² or less. With respect to near-infrared rays having a wavelength of 1 μm and far-infrared rays having a wavelength of 10 μm, aluminum does not transmit electromagnetic waves if the thickness is 15 nm or more, and nickel having the deepest absorption length among other practical metal materials has a thickness of 40 nm or more. Therefore, the two radiation prevention layers 5-1 and 5-2 are overlapped so that the electromagnetic waves do not pass through the radiation prevention layer 5-1 or the discontinuous portion at the end of the radiation prevention layer 5-2. Part A is formed. In addition, as shown in the top view of FIG. 3, although the duplication part A has the shape enclosed by the straight line of each edge part of the radiation prevention layers 5-1, 5-2, it is not restricted to this. For example, when the end portions of the radiation preventing layers 5-1 and 5-2 are curved, the overlapping portion A may have a shape surrounded by a curve.

  As shown in FIG. 2, in this overlapping portion A, there is a slight space 17. If the space 17 exists, the heat transfer property of this portion is deteriorated, and the effect of the heat insulating property is increased. On the other hand, in the modified example of FIG. 4, the space 17 of the overlapping portion A1 is reduced, but the sliding at the time of deformation is improved as described above. The radiation preventing layers 5-1 and 5-2 are not limited to aluminum, but may be any metal other than aluminum or a material having a radiation preventing function. The inner resin layer 4 may have a role of fixing the radiation preventing layer 5-1. The inner resin layer 4 may not fix the radiation preventing layer 5-2. On the other hand, the outermost resin layer 6 may have a role of preventing heat conduction from the outside air and fixing the radiation prevention layer 5-2. The outermost resin layer 6 may not fix the radiation preventing layer 5-1. Alternatively, either one or both of the radiation preventing layers 5-1 and 5-2 may not be fixed to both the resin layers 4 and 6. Since at least one of the radiation preventing layers 5-1 and 5-2 is not fixed to at least one of the resin layers 4 and 6, slipping during deformation is easily performed while holding the overlapping portion A. Note that the radiation prevention layers 5-1 and 5-2 and the resin layers 4 and 6 may be fixed by, for example, an adhesive or thermocompression bonding.

<Resin layer>
The jacket material 3 includes an inner resin layer 4 and an outermost resin layer 6. The resin layers 4 and 6 are preferably made of a material that can be stretched at the time of forming corners described later. As the resin layers 4 and 6, for example, polyamide, fluorine resin, or vinyl chloride resin can be used. Polyamide, fluororesin and vinyl chloride resin can be used for applications where the elongation is up to about 3 times. Further, as the resin layers 4 and 6, polypropylene and polyethylene can be used. Polypropylene and polyethylene can be used for applications having an elongation of up to about 8 times. The inner resin layer 4 and the outermost resin layer 6 may be made of different materials.

  FIG. 5 is a conceptual diagram of a process of bending with a mold in order to apply the vacuum heat insulating material 1 to the corner of the product. For example, the vacuum heat insulating material 1 may be installed on the female die 7, the male die 8 may be pushed down to bend the vacuum heat insulating material 1, and the corner may be formed along the concave portion of the female die 7. In addition, the method of forming a corner | angular part in the vacuum heat insulating material 1 is not restricted to the method of using the said metal mold | die.

  FIG. 6 is a conceptual cross-sectional view of the vacuum heat insulating material 1 bent at a right angle, where R is a bending radius and W is the thickness of the vacuum heat insulating material 1. Here, it is assumed that the vacuum heat insulating material 1 having a plate thickness W practically the maximum of 20 mm is bent at a right angle with a practically smallest bending radius R 5 mm. By this processing, the elongation of the outer peripheral side 3a of the jacket material is five times that of the inner side 3b of the jacket material. If the plate thickness W is 5 mm, the elongation on the outer peripheral side 3a of the jacket material is twice that of the inner side 3b of the jacket material. At this time, since 200% elongation occurs in the resin layers 4 and 6, the resin layers 4 and 6 must be made of a material capable of further elongation. If the elongation is up to about 3 times, polyamide, fluororesin or vinyl chloride resin can be used, and up to 8 times can be handled by polypropylene or polyethylene. In the case where the corner is an arc, the resin layers 4 and 6 are not damaged until the elongation resulting from the difference between the inner diameter and the outer diameter is 7 times the plate thickness W. However, if elongation beyond this is given, even if the core material 2 can be bent, the resin layer 6 of the jacket material 3 is torn and the vacuum property cannot be maintained. Therefore, when applying a load to the vacuum heat insulating material 1, it is preferable to apply a load according to the material.

  FIG. 7 is an enlarged view of the outer cover material 3 after bending in the case of FIG. 6, and A2 is the overlapping length of the radiation preventing layers 5-1, 5-2. Compared to the elongation of the resin layers 4 and 6 constituting the outer covering material 3, the radiation preventing layer 5 has a ductility of aluminum and the elongation is 50% or less at the maximum. Therefore, in order to absorb the large elongation of the resin layers 4 and 6, in FIG. 2 before bending, the elongation is the sum of the bending radius R 5 mm and the plate thickness W 20 mm of the vacuum heat insulating material 1 (R + W). The length of a quarter circle is 39.25 mm. If, for example, 50 mm is set as the overlapping length A larger than the calculated elongation, and the overlapping portion is included in the bent portion, the overlapping length A2 is secured in FIG. 7 after bending. The radiation preventing layers 5-1 and 5-2 do not become discontinuous as a radiation surface. For this reason, heat insulation is not reduced. Further, it is desirable that the overlapping portion is slippery if it is lubricated by surface treatment or the like.

(Embodiment 2)
FIG. 8 is an enlarged cross-sectional view of the outer cover material of the vacuum heat insulating material according to the second embodiment of the present invention. FIG. 9 is a plan view of FIG. In FIG. 8, the same components as those in FIG. The vacuum insulation material shown in FIG. 8 is a discontinuous portion in which the hole 19 penetrating the annular first radiation prevention layer 5-1 is a circular discontinuity as compared with the vacuum insulation material shown in FIG. There are some differences. The annular second radiation preventing layer 5-2 covers the hole 19 of the first radiation preventing layer 5-1, and the first radiation preventing layer 5-1 around the hole 19 and the second radiation. The difference is that an annular overlapping portion B is formed on which the prevention layer 5-2 is laminated.
When the corner portion (corner portion) or the like is three-dimensionally covered with the jacket material, the circular hole 19 of the first radiation preventing material 5-1 can correspond to the corner portion. Since the annular overlapping portion B is provided around the hole 19, the radiation preventing materials 5-1 and 5-2 do not become discontinuous even when a slight deviation occurs around the corner portion. Is not reduced. The overlapping portion B is preferably slippery if it is lubricated by surface treatment or the like.

(Embodiment 3)
FIG. 10 is an enlarged cross-sectional view of the envelope material of the vacuum heat insulating material according to Embodiment 3 of the present invention. In FIG. 10, the resin layers 9, 11 and the like correspond to the resin layers 4, 6 and the like in FIG. The same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. 10 is not only the outermost resin layer 11 and the radiation prevention layer 5, but also two sheets constituting an overlapping portion. The difference is that a resin layer 10 is provided between the radiation preventing layers 5-1 and 5-2. A3 is the overlapping length of the radiation preventing layer 5. The electromagnetic waves that have entered the jacket material 3 are diffusely reflected inside. If the incident angle θ of the electromagnetic wave indicated by the arrow is larger than the critical angle causing total reflection, the electromagnetic wave does not enter the vacuum heat insulating material from the outside of the jacket material 3. The condition of total reflection is given by sin θ> sin (critical angle) = 1 / (refractive index). The refractive index of the resin is 1.53 for the largest acrylic resin, and it is sufficient to see 1.6. The critical angle at a refractive index of 1.6 is 38.7 degrees.

Next, a case where the incident angle is not totally reflected will be described. That is, when the incident angle is smaller than 38.7 °, the electromagnetic wave enters the resin layer 10 from the resin layer 11 without being totally reflected. Thereafter, reflection is repeated between the upper and lower radiation prevention layers 5-1 and 5-2 and enters the resin layer 9 to reach the core material 2.
FIG. 11 is a schematic diagram when an electromagnetic wave incident on the resin layer 10 at an incident angle θ that does not totally reflect is repeatedly reflected between the upper and lower radiation prevention layers 5-1 and 5-2 and then enters the resin layer 9. is there. In FIG. 11, the light is incident on the resin layer 9 with five reflections. However, the number of reflections is for convenience of illustration, and as will be described later, the incident angle θ and the resin layer thickness D are as follows. The number of reflections varies depending on the length A3 of the overlapping portion.

Therefore, the required overlapping portion length A3 is examined. The electromagnetic wave intensity considered that the incident electromagnetic wave is sufficiently attenuated is approximately 1 / e ² = 0.135 when the original electromagnetic wave intensity is 1. When the incident angle θ is 5 °, the transmittance is 0.94. For this reason, in order for an electromagnetic wave having an electromagnetic wave intensity of 1 to pass through the resin layer 9 from the resin layer 11 at an incident angle of 5 ° to reach the electromagnetic wave intensity of 0.135, it is necessary to pass through the interface of the resin layer 32 times by reflection. is there. The 32 reflections include the interface between the atmosphere and the resin layer 11, the interface between the resin layer 11 and the resin layer 10, the interface between the resin layer 10 and the radiation prevention layer 5-1, and the resin layer 9 and the core material 2 side. Loss at the time of four transmissions. Therefore, the number of reflections (32-4) excluding the four losses is required. The overlap length A3 required for this is determined from tan 5 ° × thickness D × (32-4) times, and is 2.5 times the thickness D. Similarly, when the incident angle is 10 °, the transmissivity is 0.92, so that the overlap length A3 is 3.5 times the thickness D after 24 passes through the interface. When the incident angle is 15 °, the transmittance is 0.9, so that the overlap length A3 is 4.3 times the thickness D after passing through the interface 20 times. In the case of an incident angle of 20 °, the transmittance is 0.85, so that the overlap length A3 is 3.3 times the thickness D after passing through the interface 13 times. When the incident angle is 25 °, the transmittance is 0.75, so that the overlap length A3 is 1.4 times the thickness D after passing through the interface seven times. When the incident angle is 30 °, the transmittance is 0.62, and thus the overlap length A3 is 0.6 times the thickness D after passing through the interface five times. As described above, the necessary overlap length A3 increases from an incident angle of 5 ° to an incident angle of 15 °, and becomes 4.3 times the thickness D when the incident angle is 15 °. Thereafter, when the incident angle exceeds 15 °, the necessary overlap length A3 decreases, and at the incident angle of 30 °, the required overlap length A3 becomes 0.6 times the thickness D. Therefore, as the necessary overlap length A3, if the thickness D is set to 4.5 times or more of the thickness D that can correspond to the incident angle of 15 °, the intensity of the radiated electromagnetic wave passing from the atmosphere into the core material 2 is set. It can be made sufficiently small. In addition, since a similar loss occurs in the radiated electromagnetic wave that passes through the outer jacket material on the opposite side from the core material 2 and exits into the atmosphere, the electromagnetic wave intensity is 0.02 times or less that when it first enters from the atmosphere. Get smaller.

  FIG. 12 is an enlarged view of the jacket material 3 after bending, and A4 is the overlapping length of the radiation preventing layers 5-1, 5-2. By extending the intermediate resin layer 10, the upper and lower radiation prevention layers 5-1 and 5-2 are smoothly moved. As described in the first embodiment, if an overlapping portion is included in the bent portion, the radiation preventing layers 5-1 and 5-2 after the bending step do not become discontinuous as a radiation surface. It does not deteriorate the sex. Since the extension of the radiation preventing layers 5-1 and 5-2 is smaller than the extension of the resin layer, the overlap length A4 is shorter than the overlap length A3 of FIG.

(Embodiment 4)
FIG. 13 is an enlarged cross-sectional view of the jacket material of the vacuum heat insulating material according to the third embodiment. FIG. 14 is a plan view of FIG. In FIG. 13, the resin layers 12, 15 and the like correspond to the resin layers 4 and 6 and the like in FIG. 2, and correspond to the resin layers 9 and 11 and the like in FIG. Further, the radiation preventing layers 16-1, 16-2, 16-3 and the like correspond to the radiation preventing layers 5-1, 5-2 and the like in FIGS. Therefore, detailed description of these corresponding components is omitted. 13 is not only the outermost resin layer 15 and one radiation prevention layer 16-3, but also three layers of radiation, as compared with the vacuum insulation material shown in FIG. The resin layers 13 and 14 are provided between the prevention layers 16-1, 16-2, and 16-3 and the radiation prevention layers 16-1, 16-2, and 16-3, respectively, and the resin layer 12 is provided on the outside thereof. Is different. That is, the radiation prevention layers 16-1, 16-2, and 16-3 are multilayered from two layers to three layers, and the resin layers 13 and 14 are disposed between the radiation prevention layers 16-1, 16-2, and 16-3, respectively. Provided. Further, the radiation preventing layers 16-1, 16-2, 16-3 are provided with slits 20 extending in a direction perpendicular to the bending direction (a direction perpendicular to the paper surface) to form discontinuous portions. To do. Even if the radiation prevention layers 16-1, 16-2, and 16-3 are discontinuous, when viewed in the plate thickness direction, the radiation prevention layers 16-1, 16-2, and 16-3 are arranged so as to ensure an overlapping length A5 in which a plurality of radiation prevention layers overlap. Yes. If such an arrangement is an aluminum foil, strip-shaped aluminum foils may be arranged at an appropriate interval during production. Moreover, what is necessary is just to adjust the shape of vapor deposition in a vapor deposition film.

  The necessary overlapping length A5 in the plate surface direction of the radiation preventing layers 16-1, 16-2, 16-3 is the maximum near the incident angle of 15 ° as shown in the description with reference to FIG. As the number of resin layers increases by one, the number of resin layer interfaces increases by one. Therefore, the minimum overlap length A5 is tan 15 ° × thickness D × (20 as a general formula when the thickness D is a constant value. The overlap length represented by − (n + 1)) may be ensured. Here, n is the number of laminated resin layers. That is, by providing three or more radiation prevention layers 16-1, 16-2, and 16-3, the number of resin layers provided between the radiation prevention layers increases. An electromagnetic wave incident on the resin layer 14 between the two radiation prevention layers 16-2 and 16-3 from the upper resin layer 15 is reflected between the two radiation prevention layers 16-2 and 16-3. After repeating the above, the light enters the resin layer 13 on the lower layer side, repeats the same reflection, and further enters the resin layer 12 on the lower layer side. Therefore, by increasing the number of resin layers provided between the radiation preventing layers 16-1, 16-2, 16-3, the required radiation preventing layers 16-1, 16-2, 16-3 There is an advantage that the overlap length A5 is shortened. In the present embodiment, since n is four layers, the required overlap length A5 is 4.0 times the thickness D.

FIG. 15 is an enlarged view of the jacket material 3 after bending. As the resin between the intermediate resin layers 13 and 14 and the radiation preventing layers 16-1, 16-2, 16-3 stretches, the three layers of radiation preventing layers 16-1, 16-2, 16-3 move. It is done smoothly. Therefore, in this vacuum heat insulating material, unlike the vacuum heat insulating materials according to the first and second embodiments, the radiation preventing layers 16-1 and 16-2 after bending in a wide range without performing bending processing aiming at the overlapping portion. 16-3 does not become discontinuous as a radiating surface, so that the heat insulation is not lowered.
In FIG. 15, the resin layers 13, 14, and 15 and the radiation prevention layers 16-1, 16-2, and 16-3 are each three layers, but are not limited to three layers, and may be further multilayered.

  The vacuum heat insulating material of the present disclosure has good heat insulating properties, does not deteriorate the radiation prevention effect, and can easily form a highly reliable corner, and therefore can be applied to uses of heat insulating walls such as buildings.

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2 Core material 3 Cover material 4 Inner resin layer 5, 5-1, 5-2 Radiation prevention layer 6 Outermost resin layer 7 Female type 8 Male type 9 Resin layer 10 Resin layer 11 Resin layer 12 Resin layer 13 Resin layer 14 Resin layer 15 Resin layers 16-1, 16-2, 16-3 Radiation prevention layer 17 Space 18 Tapered end 19 Hole 20 Slit

Claims (7)

A core material containing an inorganic fibrous aggregate;
A jacket material covering at least one surface of the core material;
A vacuum heat insulating material whose inside is sealed under reduced pressure,
The jacket material is
The outermost resin layer,
A radiation preventing layer inside the resin layer;
The radiation prevention layer has, in part, an overlapping portion in which at least two layers of radiation prevention layers are laminated ,
The radiation prevention layer has a thin plate shape, and the length of the overlapping portion is tan 15 ° × (resin layer thickness) with respect to the thickness of the resin layer disposed between the laminated radiation prevention layers. The vacuum heat insulating material which is more than x (20- (number of laminated resin layers + 1)) .   The vacuum heat insulating material according to claim 1, wherein the overlapping portion has a space between the overlapping radiation prevention layers. The said vacuum heat insulating material has a corner | angular part, The plate | board thickness of the said vacuum heat insulating material is 20 mm or less, The vacuum heat insulating material of Claim 1 or 2 . The vacuum heat insulating material according to claim 3 , wherein the outermost resin layer of the jacket material is made of a material capable of elongation of 200% or more. The vacuum radiation insulating material according to any one of claims 1 to 4 , wherein the radiation prevention layer includes a metal layer, and the thickness of the metal layer is 40 nm or more. The vacuum heat insulating material according to claim 5 , wherein the metal layer of the radiation preventing layer is made of aluminum. The radiation prevention layer is
A first radiation preventing layer having a through hole;
A second radiation preventing layer that covers the through hole and forms an annular overlapping portion that is laminated with the first radiation preventing layer around the through hole;
The vacuum heat insulating material as described in any one of Claim 1 to 6 containing this.

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