JPH0694352A - Insulated box and refrigerator using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] In a heat-insulated box body that uses water-foamed rigid polyurethane foam that is foamed by carbon dioxide generated by the reaction of isocyanate with water as a foaming agent, the deterioration of heat insulation performance over time is significantly improved. To do. [Structure] The entire surface of the inner box 3 in contact with the hard polyurethane foam is a polyacrylonitrile resin film, a vinylidene chloride resin film as a carbon dioxide gas barrier film 5, a laminated film of these two or other resins, metal vapor deposition or metal foil lamination. At least one of the films is formed into a bag shape and covered, and a rigid polyurethane foam 4 that is water-foamed using water as the foaming agent is filled to form the heat-insulating box 1. [Effect] It is possible to prevent the carbon dioxide gas in the water-foamed rigid polyurethane foam from permeating the inner box and being replaced with air, and to realize a highly reliable non-Freon heat-insulating box body in which the heat insulating performance does not deteriorate with time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulation box body such as a refrigerator filled with water-foamed rigid polyurethane foam, and particularly to a heat insulation box suitable for preventing deterioration of heat insulation performance due to permeation of carbon dioxide gas in the water-foamed rigid polyurethane foam. Regarding the body

[0002]

2. Description of the Related Art As is well known, in a heat insulating box such as a refrigerator, a space formed by combining an outer box made of a metal case and an inner box made of a plastic molding is filled with a rigid polyurethane foam having closed cells. It is a heat insulating box.
The inner box of such a heat-insulating box is generally made of acrylonitrile-butadiene-styrene resin (hereinafter referred to as ABS resin), which has good compatibility with rigid polyurethane foam.
When molding rigid polyurethane foam, trichloromonofluoromethane (hereinafter referred to as CFC-11), which has a low boiling point and a low thermal conductivity of gas at room temperature, is used as a foaming agent, and is vaporized and expanded by the heat generated during molding to produce CFC- 11 Gas is contained in foam. As a result, the CFC-11 gas has excellent heat insulation performance, and since the CFC-11 gas does not easily pass through the ABS resin, the heat insulation box body does not deteriorate with time.

[0003] Examples of those related to this type of heat insulation box body include JP-A-58-153074.

[0004]

In the above-mentioned prior art, CFC-11, which has been commonly used as a foaming agent, is one of persistent CFCs (abbreviation of Chloro Fluoro Carbon) and is commonly called CFC. However, when this kind of CFC is released into the atmosphere, it is said that ozone layer depletion in the stratosphere and rise in surface temperature due to the greenhouse effect have caused a global environmental pollution problem in recent years, and the production and consumption of these CFCs are currently increasing. Is regulated and will not be usable anymore.
For this reason, various rigid polyurethane foams using alternative products have been investigated. Among them, water-foamed rigid polyurethane foams that use water as the blowing agent and are foamed by carbon dioxide gas generated by the reaction of water and isocyanate are noted. Has been done.

However, when a conventional water-foamed rigid polyurethane foam is used to form a heat-insulating box, carbon dioxide gas in the foam permeates the ABS resin and is replaced with air over time, resulting in deterioration of heat-insulating performance. was there. That is, the permeability of carbon dioxide in the foam is about 10 ² compared to CFC-11.
Remarkably high.

Therefore, an object of the present invention is to solve the above-mentioned problems, and a non-CFC having an improved box structure which does not cause deterioration of heat insulating performance with time even if a water-foamed rigid polyurethane foam is used. To provide a heat insulating box.

[0007]

The above object is a heat-insulating box body filled with water-foamed rigid polyurethane foam containing water as a foaming agent between an outer box and an inner box, wherein the water in the inner box is This can be achieved by forming a heat insulating box body in which the surface in contact with the foamed rigid polyurethane foam is covered with a carbon dioxide gas barrier film in a bag shape. The carbon dioxide gas barrier film may be a film having a property of preventing carbon dioxide gas, which is trapped as closed cells during foaming in water-foamed rigid polyurethane foam, from permeating the foam wall surface and diffusing to the outside.

Preferred carbon dioxide gas barrier films having such properties are, for example, polyacrylonitrile resin film, vinylidene chloride resin film, laminate film of polyacrylonitrile resin and vinylidene chloride resin or these and other resins, metal vapor deposition or At least one selected from the group consisting of metal foil laminate films can be mentioned. These films are satisfactory as carbon dioxide gas barrier films and have good compatibility with the resin forming the inner box, and moreover, this film is a barrier for preventing the inner box from being subjected to chemical attack such as cracking due to rigid polyurethane foam. It also has the action of.

Further, instead of covering the surface of the inner box contacting the rigid polyurethane foam with the carbon dioxide gas barrier film, the surface of the inner box is subjected to a surface coating treatment with a resin constituting the carbon dioxide gas barrier film, The carbon dioxide barrier film may be formed directly on the surface of the inner box.

A typical use of such a heat insulating box is various refrigerators for storing foods, but it can also be widely applied to various storage boxes that require heat insulation such as medicines.

[0011]

A carbon dioxide barrier film such as the above polyacrylonitrile resin film, vinylidene chloride resin film, polyacrylonitrile resin and vinylidene chloride resin film or a laminate film of these and other resins, and metal vapor deposition or a metal foil laminate film, Since the permeation of carbon dioxide gas is extremely low, the carbon dioxide gas in the water-foamed rigid polyurethane foam can be prevented by forming these films into bags and covering the entire inner box, or by forming these films directly on the surface of the inner box. It acts to prevent air from entering through the box,
Almost no deterioration of heat insulation performance occurs. Further, by covering the entire inner box with each of the above-mentioned films, the inner box material itself is not subjected to chemical attack by the hard polyurethane foam, and therefore inexpensive styrene resin or the like can be used.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a heat insulating box is applied to a refrigerator casing will be described below as an embodiment of the present invention with reference to the drawings. FIG. 1 is a partially cutaway perspective view of the heat insulating box, and FIG. 2 is a cross sectional view of FIG. As shown in the figure, a rigid polyurethane foam 4 is filled between an outer box 2 made of a metal case and an inner box 3 made of a plastic molded body to form a heat insulating box body 1
Is formed. In the present embodiment, as shown in FIG. 2, the entire surface of the inner box 3 (made of styrene resin) in contact with the hard polyurethane foam is used as the carbon dioxide gas barrier film 5 as a polyacrylonitrile resin film having a thickness of 30 μm or a thickness of 30 μm. A vinylidene chloride resin film, a metal-deposited laminated film, or a metal foil laminated film is processed and covered in a bag shape, respectively, and a water-foamed rigid polyurethane foam 4 in which water is used as the foaming agent is filled and the heat insulating box 1 ( (Including the door).

In this way, in this embodiment, carbon dioxide gas in the water-foamed rigid polyurethane foam 4 does not permeate the inner box 3 and is replaced by air, and deterioration of the heat insulating performance with time can be prevented. It should be noted that the polyacrylonitrile resin film and the vinylidene chloride resin film do not have sufficient carbon dioxide gas barrier properties when the thickness is too thin, and therefore 20 μm or more is preferable for practical use.

The same effect can be obtained by forming this film directly on the surface of the inner box instead of covering the entire surface of the inner box which is in contact with the rigid polyurethane foam 4 with the bag-shaped carbon dioxide gas barrier film 5. To be Further, in this embodiment, only water-foamed rigid polyurethane foam is used as the heat insulating material, but it goes without saying that the same effect can be obtained by using a well-known vacuum heat insulating material in combination.

[0015]

As described above, according to the present invention, the intended purpose can be achieved. That is, there is provided a highly reliable non-Freon insulation box body which is a heat insulation box body formed by filling a water-foamed rigid polyurethane foam in which all of the foaming agents are filled with water, and in which the heat insulation performance does not deteriorate with time. Can be provided.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a heat insulating box according to an embodiment of the present invention.

2 is a cross-sectional view of FIG.

[Explanation of symbols]

1 ... Insulation box, 2 ... Outer box, 3 ... Inner box, 4 ... Water-foamed rigid polyurethane foam, 5 ... Carbon dioxide gas barrier film.

Claims (4)

[Claims] 1. A heat-insulating box body obtained by filling a water-foamed rigid polyurethane foam using water as a foaming agent between an outer box and an inner box, wherein a surface of the inner box which is in contact with the water-foamed rigid polyurethane foam is A heat-insulating box body covered with a carbon dioxide gas barrier film in a bag shape. 2. A heat-insulating box body obtained by filling a water-foamed rigid polyurethane foam using water as a foaming agent between an outer box and an inner box, wherein the surface of the inner box which is in contact with the water-foamed rigid polyurethane foam is An insulating box body covered with a carbon dioxide gas barrier film. 3. A carbon dioxide gas barrier film, a polyacrylonitrile resin film, a vinylidene chloride resin film, a polyacrylonitrile resin and vinylidene chloride resin, or a laminate film of these and other resins,
The heat-insulating box body according to claim 1 or 2, which is composed of at least one film selected from the group consisting of metal vapor deposition or metal foil laminated film. 4. A refrigerator comprising a heat insulating box according to claim 1 as a housing.