JP2016142366A - Vacuum heat insulation material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure showing a superior heat insulation characteristic even if a corner part is formed by bending a vacuum heat insulation material.SOLUTION: There are provided a core material 2 that is non-organic fibrous aggregate and an outer covering material. The outer covering material has an outer-most resin layer 6 and a radiation preventive layer 5 inside the resin layer. The radiation preventive layer 5 has corrugated shapes in the longitudinal direction. A crest height or a valley depth of one corrugation is set to be 0.9 times to 4 times of a corrugation width, resulting in that even if the vacuum heat insulation material is bent to form a corner part, the film of an outer shell material is extended. The radiation preventive layer 5 having a radiation effect with a small ductility can assure the radiation preventive effect since the crest or valley of the corrugated structure becomes low and extends toward a direction of external force and it is possible to form the corner part without reducing the reliability in operation.SELECTED DRAWING: Figure 3

Description

  The present invention 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, and are mostly applied to products such as refrigerators as they are because of their manufacturing method and reliability. . 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.

  Examples of application of the vacuum heat insulating material include a fiber disposed at a right angle to the heat insulating direction to suppress heat conduction (for example, refer to Patent Document 1), or a metal foil or metal vapor deposition film having an excellent radiant heat shielding effect. (For example, see Patent Document 2), a plate-like substance such as mica having an excellent shielding effect against radiant heat, integrated with a core material such as a glass mat and a resin and laminated in a plane (for example, see Patent Document 3) )

  Among these, the vacuum heat insulating material of Patent Document 3 is a composite material in which a slurry liquid in which a plate-like substance such as mica having excellent radiation heat shielding effect is dispersed is uniformly dispersed on a glass mat, and the plate-like substances are laminated in both directions. Formed with.

  Moreover, the site | part which should be insulated is not necessarily plane shape.

  Specifically, if there are corners, protrusions or steps in the heat insulation part, the vacuum heat insulation can be bent, drilled, etc., or the shape of the exterior material can be molded in advance to achieve vacuum insulation. A method for matching the shape of the material with the shape of the heat insulating 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 surfaces of the outer shell material are compressed using a mold having a convex portion, and the inside of the outer shell material is vacuumed. There is one that forms a recess on the surface by exhausting (see, for example, Patent Document 4). In addition, the inside of the film container filled with a heat insulating material is decompressed, and a plate-like vacuum heat insulating material produced by sealing by heat sealing is put into a vacuum container and molded by a mold, and this is held. (For example, refer to Patent Document 5).

JP-A-60-208696 JP 62-013979 A 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 at the discontinuous portions derived from these finite lengths and radiation increases. 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.

  In the case of applying a vacuum heat insulating material to a product having a corner, 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 that said it would be a thing. 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.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a vacuum heat insulating material that has excellent heat insulating properties and can easily form highly reliable corners.

  In order to achieve the above object, the vacuum heat insulating material of the present invention comprises a core material that is an inorganic fibrous aggregate, and a jacket material. The jacket material is a resin layer in contact with the core material, and radiation on the outside thereof. The radiation prevention layer has a wave shape in the longitudinal direction, and the height of the peak of one wave or the depth of the valley is 0.9 to 4 times the width of the wave. is there.

  Even if the vacuum insulation material is bent to provide corners, the outer shell film is stretched, and the radiation prevention layer with a small ductility radiation effect reduces the peaks and valleys of the wavy structure. Therefore, the corner portion can be formed without deteriorating the reliability.

  As described above, according to the vacuum heat insulating material of the present application, 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.

Sectional drawing of the vacuum heat insulating material in Embodiment 1 of this invention The enlarged view of the process of providing a wavy shape to the radiation prevention layer in Embodiment 1 of this invention The cross-sectional enlarged view of the jacket material of the vacuum heat insulating material in Embodiment 1 of this invention The conceptual diagram of the process of bending the vacuum heat insulating material in Embodiment 1 of this invention with a metal mold | die. Cross-sectional conceptual diagram bent at a right angle of the vacuum heat insulating material in Embodiment 1 of the present invention Schematic diagram of elongation of resin layer and deformation of radiation prevention layer in Embodiment 1 of the present invention The cross-sectional enlarged view of the jacket material after the bending process of the vacuum heat insulating material in Embodiment 1 of this invention The cross-sectional enlarged view of the jacket material of the vacuum heat insulating material in Embodiment 2 of this invention The enlarged view of the jacket material of the vacuum heat insulating material in Embodiment 3 of this invention

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

(Embodiment 1)
FIG. 1 is a cross-sectional view of a vacuum heat insulating material according to Embodiment 1 of the present invention. In FIG. 1, 1 is a vacuum heat insulating material, 2 is a core material, and 3 is a jacket material. The core material 2 is glass wool.

  FIG. 2 is an enlarged view of a step of imparting a wave shape to the radiation preventing layer 5. In FIG. 2, 4 is an inner resin layer in contact with the core material 2, and 5 is a radiation preventing layer.

  As shown in FIG. 2 (a), the radiation prevention layer 5, which is a foil strip, is provided on the upper part of the resin layer 4 in a state before having a wave shape.

  Next, as shown in FIG. 2B, when the gear 7 having a predetermined shape is rotated in the laminate of the resin layer 4 and the radiation prevention layer 5 and moved while being pushed, as shown in FIG. The wave shape remains. At this time, when the plurality of radiation prevention layers 5 overlap each other at the joint of the radiation prevention layer 5, the corrugated shape may be formed as it is. Further, after the wave shape is formed, the resin layer may be formed by coating or the like.

  FIG. 3 is an enlarged cross-sectional view of the jacket material 3, and 6 is a laminated structure of the outermost resin layer.

  The radiation preventing layer 5 is an aluminum foil (plate thickness is 0.1 mm) and has a wave shape with a height H and a width W. 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 the vacuum heat insulating material 1, since the degree of vacuum 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. Conductive heat transfer may be achieved by reducing the contact area between the core material 2 and the jacket material 3 or arranging a resin material having poor thermal conductivity on the contact surface with the core material 2. As for radiant heat transfer, heat transfer from the higher temperature side can be prevented by providing a substance that shields electromagnetic waves halfway.

  For this reason, the aluminum foil is installed as the radiation preventing layer 5 on the outer side of the inner resin layer 4. Aluminum is a metal with excellent ductility and workability. In a substance, there is a thickness called absorption length. For near-infrared with a wavelength of 1 μm and far-infrared with a wavelength of 10 μm, aluminum has a thickness of 15 nm or more, and even nickel having the deepest absorption length among other practical metal materials has a thickness of 40 nm or more and hardly transmits electromagnetic waves. .

  The radiation preventing layer 5 may be any metal other than aluminum or any other material having a radiation preventing function. The outermost resin layer 6 serves to prevent heat conduction from the outside air and to fix the radiation prevention layer 5.

  FIG. 4 is a conceptual diagram of a process of bending with a mold in order to apply the vacuum heat insulating material 1 to a corner portion of a product. The vacuum heat insulating material 1 is installed on the female mold 8, and the male mold 9 is pushed down and bent.

  FIG. 5 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 T is a plate thickness of the vacuum heat insulating material.

  Here, it is assumed that the vacuum heat insulating material 1 having a plate thickness T practically the maximum of 20 mm is bent at a right angle with a practically smallest bending radius R5 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. Further, if the plate thickness T 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 layer 4 and the resin layer 6, the material must be capable of further elongation.

  If the elongation is up to about 3 times, it can be handled by polyamide, fluororesin or vinyl chloride resin, and if it is up to 8 times, it can be handled by polypropylene or polyethylene having an elongation of 800%. When the corner is an arc, the elongation caused by the difference between the inner diameter and the outer diameter does not damage the resin layers 4 and 6 up to 7 times the bending radius R. Even if it can be bent, the resin layer 6 of the jacket 3 is torn and the vacuum property cannot be maintained.

  About the radiation prevention layer 5, a wavy shape will be extended corresponding to the expansion | extension of the resin layers 4 and 6. FIG.

  FIG. 6 is a schematic diagram showing the relationship between the elongation of the resin layer and the deformation of the radiation preventing layer. FIG. 6A shows a state before the resin layer is stretched, and FIG. 6B shows a state after the resin layer is stretched.

  The radiation prevention layer 5 is a straight line, and the wave is a triangle having a side length L. When double expansion occurs in the resin layers 4 and 6, half of the wave width W extends twice. That is, if the relationship of L> (W / 2) × 2 is satisfied, the radiation preventing layer 5 is not torn off by the elongation of the resin layer 4 or the resin layer 6.

When this relationship is satisfied, in the state of FIG. 6A before the elongation occurs, the wave height H> square root (L ² − (W / 2) ² ) = 0. 87W. That is, if the wave height H is 0.9 times or more the width W, the radiation prevention layer 5 will not break even if it is doubled. When the wave shape is convex upward or downward, the length of L becomes longer, so there is more room for breakage.

The same relationship as the mountain can be applied to the valley. If the elongation is less than twice, the height H may be less than 0.9 times the width W. Similarly, when the maximum elongation of 8 times occurs for the resin layer, if the relationship of L> (W / 2) × 8 is satisfied, the wave height H> square root (L ² − (W / 2) ² ) = 4.0W. That is, if the height H is set to 4 times the width W or more, the radiation preventing layer 5 does not break even if the elongation is 8 times. However, if the height H is increased, the jacket material 3 becomes thicker.

  FIG. 7 is an enlarged cross-sectional view of the jacket material 3 stretched by bending. The resin layer 4 and the resin layer 6 become thinner due to elongation, the height of the wavy peaks and the depth of the valleys of the radiation preventing layer 5 become smaller, and become linear when fully stretched. In the present embodiment, the radiation preventing layer 5 is made of an aluminum foil, but may be made of another metal or an aluminum vapor deposition film.

(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.

  In FIG. 8, 10 and 11 are resin layers, and 12 is a radiation preventing layer. 8 differs from FIG. 2 in that the wave-like structure of the radiation preventing layer 12 is limited to a part. If the place where the vacuum heat insulating material 1 is subjected to bending is known, if the corrugated portion of the radiation preventing layer 12 is applied to that place, the radiation preventing layer 12 will not be stretched and broken by bending. Moreover, since the full length of the expensive radiation prevention layer 12 becomes short, there also exists an advantage that the usage-amount decreases.

(Embodiment 3)
FIG. 9 is an enlarged view of the jacket material of the vacuum heat insulating material according to the third embodiment of the present invention.

  9A shows a state when the radiation preventing layer 13 is viewed from above, and FIG. 9B is an enlarged view of the cross-sectional direction of the line MN in the top view of FIG. 9A. It is.

  In FIG. 9, the difference from the first and second embodiments is that the wavy peaks 14 and valleys 15 are formed in a lattice pattern in the plane, and the resin layers 16 and 17 are formed vertically.

  By forming a wave-like structure in the plane of the radiation preventing layer 13, the radiation preventing layer 13 is not broken not only by one-dimensional bending but also by two-dimensional bending such as the apex of the housing. In FIG. 9, the wave peaks and valleys are equally spaced and the smoothing portions 18 are present, but the peaks and valleys may be non-equally spaced or the smoothing portions 18 may not be present.

  The vacuum heat insulating material of the present invention has good heat insulating properties because the radiation preventing effect does not decrease, and can easily form highly reliable corners, and can be applied to heat insulating wall applications such as buildings. .

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2 Core material 3 Cover material 4 Resin layer 5 Radiation prevention layer 6 Resin layer 7 Gear 8 Female type 9 Male type 12 Radiation prevention layer 13 Radiation prevention layer 14 Mountain 15 Valley 16 Resin layer 18 Smooth part

Claims (6)

A vacuum heat insulating material including a core material including an inorganic fibrous aggregate, and a covering material that covers at least one surface of the core material, the inside of which is sealed under reduced pressure,
The jacket material includes a resin layer disposed in contact with the core material, and a radiation prevention layer on the outside of the resin layer, and the radiation prevention layer has a wave shape in the longitudinal direction. The height of the mountain or the depth of the valley is 0.9 to 4 times the width of the wave,
Vacuum insulation material characterized by The vacuum heat insulating material according to claim 1, wherein the resin layer is smooth. 3. The vacuum heat insulating material according to claim 1, wherein peaks or valleys of the radiation preventing layer are present in a lattice shape within a surface of the outer jacket material. The vacuum heat insulating material according to any one of claims 1 to 3, wherein the resin layer is a material capable of elongation of 200% or more. The vacuum heat 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 is aluminum.

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