JP2012077864A - Vacuum heat insulation material and heat insulation box using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of heat insulation performance caused by deterioration of the degree of vacuum due to desorption of adsorbed moisture.SOLUTION: In a vacuum heat insulation material 5 whose inside is vacuumized by sealing a core material 1 with a gas barrier external packing material 2, a laminate film 4 forming the external packing material is composed of a heat deposited layer 8, a gas barrier layer 7, and a scratch-prevention layer 11, the gas barrier layer is formed from a plastic film composed of an ethylene vinyl alcohol copolymer resin, and to one side thereof, aluminum evaporation, alumina evaporation, or silica evaporation is applied, a surface applied with the evaporation is arranged on the heat deposition layer side, and the scratch prevention layer is formed from a plastic film, and to one side thereof, aluminum evaporation, alumina evaporation or silica evaporation is applied, and a surface applied with the evaporation is arranged on the gas barrier layer side.

Description

  The present invention relates to a vacuum heat insulating material and a heat insulating box using the vacuum heat insulating material, and more particularly to a vacuum heat insulating material and a heat insulating box suitable for use in a refrigeration apparatus.

  Conventionally, urethane foam has been used as a heat insulating material used in a heat insulating box such as a refrigerator. However, in recent years, vacuum heat insulating material has better heat insulating performance than urethane foam due to market demand for energy saving and space saving and large capacity. The form which embeds in urethane foam and uses together has come to be used. Such a vacuum heat insulating material is used not only for a refrigerator but also for a heat insulating box of a cooling device such as a heat storage, a vehicle air conditioner, and a water heater.

  The vacuum heat insulating material is made of powder, foam, in an outer packaging material in which two plastic laminate films using aluminum foil for the gas barrier layer (same as the air barrier layer) are stacked and the peripheral part is thermally welded into a bag shape. A fiber body or the like is inserted as a core material, and the inside is maintained at a vacuum level of several Pa or less.

  As described above, the outer packaging material of the vacuum heat insulating material mainly uses aluminum foil for the gas barrier layer. However, although aluminum foil is excellent in gas barrier properties, it has a drawback that heat insulation performance is lowered due to heat wrapping called heat bridge. Therefore, at present, outer packaging materials using a vapor deposition film obtained by vapor deposition on one side of a plastic film are mainly used. For example, a plastic film made of an ethylene vinyl alcohol copolymer resin with excellent gas barrier properties is used for the gas barrier layer, and aluminum deposition is performed on one side of the plastic film, and the surface on which the aluminum deposition is performed is disposed on the heat welding layer side. What has been proposed has been proposed (see, for example, Patent Document 1).

JP-A-10-122477 (Claim 1, FIG. 2)

  However, if one side of a plastic film made of an ethylene vinyl alcohol copolymer resin is subjected to aluminum vapor deposition and the aluminum vapor deposited surface is arranged on the heat-welded layer side, ethylene vinyl alcohol Since the copolymer resin is hydrophilic, it swells by adsorbing moisture from the surface on the side of the non-deposited heat-deposited layer, causing the vapor deposition layer to peel off, resulting in poor heat insulation performance.

  Such a problem can be solved if a vapor deposition layer can be formed on both sides of a plastic film made of an ethylene vinyl alcohol copolymer resin, but is technically difficult to manufacture.

  The technical problem of the present invention is to make it possible to suppress the deterioration of the heat insulation performance due to the deterioration of the degree of vacuum due to the desorption of adsorbed moisture.

  The vacuum heat insulating material according to the present invention has the following configuration. That is, in a vacuum heat insulating material in which the core material is sealed with a gas barrier outer packaging material and the inside is evacuated, the outer packaging material is formed by laminating two laminated films formed by laminating a plurality of plastic films. In which the laminate film is composed of a heat-welded layer, a gas barrier layer, and an anti-scratch layer, and the gas barrier layer is an ethylene vinyl alcohol copolymer resin. The aluminum film, the alumina vapor deposition, or the silica vapor deposition is performed on one side of the plastic film constituted by: the surface on which the vapor deposition is performed is arranged on the heat welding layer side, and the scratch preventing layer is , One side of the plastic film is subjected to aluminum vapor deposition, alumina vapor deposition, or silica vapor deposition, and the surface on which the vapor deposition is performed on the gas barrier layer side It is obtained by location.

  In the vacuum heat insulating material according to the present invention, since the plastic film composed of the ethylene vinyl alcohol copolymer resin is sandwiched between the vapor deposition layers from both sides, the ethylene vinyl alcohol is difficult to absorb moisture, In addition, the heat insulation performance improves over time.

It is a perspective view which shows the vacuum heat insulating material which concerns on embodiment of this invention. It is a disassembled perspective view which shows the vacuum heat insulating material which concerns on embodiment of this invention. It is sectional drawing which expands and shows the heat welding part of the outer packaging material of the vacuum heat insulating material which concerns on embodiment of this invention. It is detailed sectional drawing which expands and shows the laminated structure of the laminated film of the outer packaging material of the vacuum heat insulating material which concerns on embodiment of this invention. It is detail sectional drawing which expands and shows the laminated structure of the laminated film of the outer packaging material of a comparative example. It is detail sectional drawing which expands and shows the laminated structure of the laminated film of the outer packaging material of a comparative example. It is a figure which shows the heat conductivity measurement result of the vacuum heat insulating material which concerns on embodiment of this invention compared with a comparative example. It is a longitudinal cross-sectional view which shows the heat insulation box using the vacuum heat insulating material of this invention.

The present invention will be described below with reference to illustrated embodiments.
FIG. 1 is a perspective view showing a vacuum heat insulating material according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view.

  As shown in FIGS. 1 and 2, the vacuum heat insulating material 5 of the present embodiment includes an outer packaging material 2 having air barrier properties, and a core material 1 and a gas adsorbent 3 enclosed in the outer packaging material 2. The inside of the outer packaging material 2 is depressurized to a predetermined degree of vacuum.

  The core material 1 uses polyethylene terephthalate resin fibers having an average fiber diameter of 13 μm, and the dimensions are adjusted to those of the conventional desired core material.

  The outer packaging material 2 is formed by laminating a plurality of laminated films 4 formed by laminating a plurality of plastic films as shown in FIG. 1 to FIG. The heat welding layer 8, the gas barrier layer 7, and the scratch preventing layer 11 are configured.

  The heat welding layer 8 is formed of a 50 μm thick plastic film made of a low density polyethylene resin.

  The gas barrier layer 7 is formed of a plastic film having a thickness of 15 μm made of an ethylene vinyl alcohol copolymer resin having a vapor deposition layer 7a on which one side is vapor-deposited. It is arranged in.

  The damage prevention layer 11 is formed of a first damage prevention layer 9 and a second damage prevention layer 6. Of these, the first scratch-preventing layer 9 located on the side adjacent to the gas barrier layer 7 is formed of a 12 μm thick plastic film made of polyethylene terephthalate resin having a vapor-deposited layer 9a on one side of which is vapor-deposited alumina. The vapor-deposited surface is disposed on the gas barrier layer side. Moreover, the 2nd damage prevention layer 6 located in the anti-gas barrier layer side is formed with the 15-micrometer-thick plastic film comprised with a stretched nylon.

  That is, the laminate film 4 includes two plastic films having a vapor deposition layer, and the direction of each vapor deposition layer is a plastic film made of ethylene vinyl alcohol copolymer resin of the gas barrier layer 7 as shown in FIG. The plastic films are formed so as to be directly sandwiched, and the plastic films are bonded to each other by an adhesive 10 by dry lamination.

  As described above, the vacuum heat insulating material 5 of the present embodiment is configured so that the plastic film made of the ethylene vinyl alcohol copolymer resin that becomes the gas barrier layer 7 is directly sandwiched between the vapor deposition layers from both sides. Ethylene vinyl alcohol is difficult to absorb moisture, and heat insulation performance is improved both initially and over time.

  Here, the plastic film made of polyethylene terephthalate resin has been subjected to alumina deposition, and the plastic film made of ethylene vinyl alcohol copolymer resin has been described as an example of aluminum film, The type of vapor deposition may be any of aluminum vapor deposition, alumina vapor deposition, silica vapor deposition and the like.

  Further, as long as a plastic film composed of an ethylene vinyl alcohol copolymer resin is directly sandwiched between vapor deposition layers, vapor deposition may be provided on other layers. That is, a film made of a plastic material other than polyethylene terephthalate resin can be used as the first scratch-preventing layer 9 located on the side adjacent to the gas barrier layer 7. Furthermore, the number of plastic films constituting the laminate film is four here, but it may be any number of layers.

  In addition, as Comparative Example 1 of a laminate film having a four-layer structure, as shown in FIG. 5, a plastic film vapor-deposited layer (alumina vapor-deposited) 9 a composed of polyethylene terephthalate resin is used as a plastic film composed of ethylene-vinyl alcohol copolymer resin. A plastic film vapor-deposited layer (aluminum vapor-deposited) 7a composed of an ethylene vinyl alcohol copolymer resin was directed toward the polyethylene terephthalate resin side.

  Further, as Comparative Example 2 of a laminate film having a four-layer structure, a plastic film deposition layer (alumina deposition) 9a composed of polyethylene terephthalate resin is directed toward the plastic film composed of stretched nylon as shown in FIG. A plastic film vapor-deposited layer (aluminum vapor-deposited) 7a composed of a vinyl alcohol copolymer resin was directed to the plastic film side composed of a low-density polyethylene resin.

  Then, the outer packaging material 2 is prepared using each of the laminate films formed as described above, the core material 1 is inserted into each outer packaging material 2 together with the adsorbent 3, and the vacuum packaging machine is used to The vacuum heat insulating material 5 was formed by sealing after holding at 0.0 Pa or less for a certain time.

  The core material 1 is not limited to polyethylene terephthalate resin fibers, but is a foamed continuous foam, a powder material such as silica or pearlite, calcium silicate, or the like, glass, polyethylene, polystyrene, polypropylene, polylactic acid, or the like, Etc. may be used.

  The adsorbent 3 used here is calcium oxide that can absorb the moisture of the organic fiber aggregate of the polyethylene terephthalate resin that is the core material 1, but even if a gas adsorbent such as synthetic zeolite or molecular sieves is used. Good.

  The heat insulation performance of the vacuum heat insulating material 5 using this outer packaging material was evaluated by thermal conductivity. The thermal conductivity was measured with a thermal conductivity measuring machine manufactured by Eihiro Seiki Co., Ltd. The results are shown in FIG.

  As is apparent from FIG. 7, the initial performance (after 1 day at room temperature) was good in Example 1 and Comparative Example 2 and had equivalent performance, but deteriorated with time (50 ° C., 80% RH, 6 days later). When it sees, it turned out that only Example 1 is good.

  Comparative Example 1 was bad because a hydrophilic material such as an ethylene vinyl alcohol copolymer resin was used, and the thermal conductivity deteriorated due to the deterioration of the degree of vacuum due to the desorption of adsorbed moisture. Conceivable.

  Comparative Example 2 was bad because there was a vapor deposition layer between the gas barrier layer composed of ethylene vinyl alcohol copolymer resin and the heat-welded layer, so there was no mixing of adsorbed moisture, and there was no problem in the initial performance. However, it is considered that the moisture that has entered from the outside with the passage of time is mixed and expanded, and the aluminum deposition is broken.

  As in Example 1, a vacuum film having better heat insulation properties at the beginning and over time can be obtained by directly sandwiching a plastic film made of an ethylene vinyl alcohol copolymer resin with a vapor deposition layer. Insulation could be formed.

  In addition, as resin used for the 2nd damage prevention layer 6 of the surface side of the outer packaging material 2, it is not limited to nylon resin, Polyethylene terephthalate resin, polypropylene resin, polyvinyl chloride, etc. can be used. Therefore, the scratch-preventing layer 11 may be formed only of a plastic film made of polyethylene terephthalate resin having a vapor-deposited layer 9a subjected to alumina vapor deposition on one surface.

  Moreover, as resin used for the heat welding layer 8, it is not limited to a low density polyethylene resin, A high density polyethylene resin and a polyacrylonitrile resin are also employable.

  FIG. 8 is a longitudinal sectional view showing a heat insulating box 30 using the vacuum heat insulating material 5 of the present embodiment.

  The heat insulation box 30 includes an outer box 31 and an inner box 32 disposed inside the outer box 31. The vacuum heat insulating material 5 is disposed between the outer box 31 and the inner box 32, and the outer box 31 and the vacuum heat insulating material 5 and between the inner box 32 and the vacuum heat insulating material 5 are filled with a heat insulating material 33 made of urethane foam, and the vacuum heat insulating material 5 is placed in the urethane foam. It is buried and used together. A spacer 34 is disposed between the outer box 31 and the vacuum heat insulating material 5 to secure the flow path when the vacuum heat insulating material 5 is positioned and the heat insulating material 33 is filled.

  The heat insulation box 30 using the vacuum heat insulating material 5 of the present embodiment is held at the middle position of the wall thickness of the vacuum heat insulating material 5 by the spacer 34, and the vacuum heat insulating material 5 is completely insulated in the urethane foam. Both the outer box 31 of the material 5 and the vacuum heat insulating material 5 and between the inner box 32 and the vacuum heat insulating material 5 are filled with urethane foam.

  Thus, by using the vacuum heat insulating material 5 of the present embodiment having a low thermal conductivity and high heat insulating performance for the heat insulating box 30, the heat insulating box 30 having better heat insulating properties at the beginning and over time can be obtained. Obtainable.

  Here, the heat insulating box 30 in which both sides of the vacuum heat insulating material 5 are filled with urethane foam so that the vacuum heat insulating material 5 is completely embedded in the urethane foam is described as an example. Instead, for example, the urethane foam may be filled in a state in which the vacuum heat insulating material 5 is pressed against the inner wall of the outer box 31 or the inner box 32. In this case, the same effect can be obtained.

  DESCRIPTION OF SYMBOLS 1 Core material, 2 Outer packaging material, 3 Gas adsorbent, 4 Laminate film, 5 Vacuum heat insulating material, 6 2nd damage prevention layer, 7 Gas barrier layer, 7a, 9a Evaporation layer, 8 Thermal welding layer, 9 1st damage Prevention layer, 10 Adhesive, 11 Damage prevention layer, 30 Heat insulation box, 31 Outer box, 32 Inner box, 33 Heat insulation material, 34 Spacer.

Claims (5)

In a vacuum heat insulating material in which the core material is sealed with a gas barrier outer packaging material and the inside is evacuated,
The outer packaging material is a laminated film in which a plurality of plastic films are laminated, and the peripheral portion is thermally welded into a bag shape,
The laminate film is composed of a heat-welded layer, a gas barrier layer, and an anti-scratch layer,
The gas barrier layer is obtained by performing aluminum vapor deposition, alumina vapor deposition, or silica vapor deposition on one side of a plastic film composed of an ethylene vinyl alcohol copolymer resin, and the surface on which the vapor deposition is performed is on the heat welding layer side Are arranged in
The scratch-preventing layer is one that has been subjected to aluminum vapor deposition, alumina vapor deposition, or silica vapor deposition on one side of the plastic film, and the surface on which the vapor deposition has been performed is disposed on the gas barrier layer side.
Vacuum insulation characterized by that.   2. The vacuum heat insulating material according to claim 1, wherein the scratch-preventing layer is composed of a plurality of plastic films, and the vapor deposition is performed on a plastic film located on a side adjacent to the gas barrier layer.   A heat insulation comprising an outer box and an inner box arranged inside the outer box, wherein the vacuum heat insulating material according to claim 1 or 2 is arranged between the outer box and the inner box. box.   The heat insulation box according to claim 3, wherein a heat insulation material is filled in both or either of the outer box and the vacuum heat insulation material and between the inner box and the vacuum heat insulation material. .   5. The heat insulation according to claim 4, wherein a spacer is provided between the outer box and the vacuum heat insulating material for positioning the vacuum heat insulating material and securing a flow path when filling the heat insulating material. box.

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