JPH0794950B2 - Insulation box - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating box used in a refrigerator / freezer or the like.

2. Description of the Related Art In recent years, from the viewpoint of energy saving, it has been strongly desired to reduce the thermal conductivity of the foamed heat insulating material and improve the heat insulating property.
Therefore, in the production of rigid urethane foam, which is a typical foam insulation material, various improvements have been made from the raw material side, by removing the polyether polyol and isocyanate used as the main raw materials, the foam stabilizer, the catalyst, and the foaming agent used as the auxiliary raw materials. Efforts are being made. In order to reduce the thermal conductivity of the rigid urethane foam particularly in such an approach, it is important to improve the gas thermal conductivity of the gas component in the bubbles. In particular, trichlorofluoromethane (hereinafter R-11) is used as a foaming agent. It was essential to fill the foam cells with R-11 gas.

However, avoid the phenomenon that the moisture contained in the raw material system reacts with the isocyanate due to residual moisture in the urethane foam raw material or moisture absorption at the time of injecting it into the heat insulation box, and the generated carbon dioxide gas is contained in the foam bubbles. I couldn't. The gas thermal conductivity of R-11 is 0.0067kcal / mhr ℃
On the other hand, the gas thermal conductivity of carbon dioxide is 0.0125 kcal
The presence of carbon dioxide gas was a major problem in improving the thermal conductivity of the foam and the thermal conductivity of the foam.

Conventionally, for the removal of carbon dioxide gas generated from the system, for example, a method disclosed in Japanese Utility Model Publication No. Sho 53-36297 has been proposed. This Japanese Utility Model Publication No. 53-36297 is characterized in that carbon dioxide gas generated from coffee beans filled in a closed container is adsorbed and removed by molecular sieves enclosed in the closed container.

Problems to be Solved by the Invention However, for coffee beans having a filling space, such as coffee beans, there is no problem because the generated carbon dioxide gas moves through the voids and is adsorbed by the carbon dioxide gas adsorbent molecular sieves. However, in the case of a hard urethane foam, even if a carbon dioxide gas adsorbent is embedded, since the bubbles are closed cells, the movement of carbon dioxide gas is slow and there is a problem that the carbon dioxide gas cannot be adsorbed during the period from the production to the actual use. Referring to FIG. 4, reference numeral 1 is a heat-insulating box, which is an outer box 2 made of an iron plate, an inner box 3 made of plastic, and an outer box 2.
Rigid urethane foam 4 integrally foamed between the inner box 3 and
It consists of 5 is a molecular sieve (9F made by Toyo Soda Co., Ltd.) filled in a breathable bag 6, which is previously disposed between the outer box 2 and the inner box 3 and integrally foamed.

In such a configuration, the carbon dioxide gas contained in the bubbles is blocked by the bubble film of the rigid urethane foam 4 which is a closed cell, and there is no pressure difference between the bubble film and the molecular sieves 5, so that the diffusion rate is However, there was a phenomenon that it did not reach the molecular sieves 5 slowly and easily.

There is also a phenomenon that air having a high gas thermal conductivity, which stays in the particles of the molecular sieves 5 and between the particles, enters into the bubbles of the rigid urethane foam 4 which is negative pressure due to the adsorption of carbon dioxide gas. Therefore, the heat conductivity of the rigid urethane foam 4 could not be sufficiently improved because the carbon dioxide gas could not be completely adsorbed during the period from the production of the heat insulating box 1 to the actual use thereof.

In view of the above problems, the present invention aims at adsorbing and removing carbon dioxide gas contained in a rigid urethane foam in a short time, improving the thermal conductivity of the rigid urethane foam, and improving the heat insulating performance of a heat insulating box. And

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a jacket made of a plastic film in which a carbon dioxide adsorbent is dissolved or swollen by a Freon-based compound which is a foaming agent of a rigid urethane foam. The packaged package is arranged between an inner box and an outer box to form a heat insulating box body integrally foamed with hard urethane foam.

Action With the above configuration, the jacket of the vacuum package filled with the carbon dioxide adsorbent is subjected to a chemical action such as dissolution or swelling by the fluorocarbon gas in the bubbles of the rigid urethane foam, and the crack or pinhole is generated in the jacket. Etc. occur. Only from this point, the adsorption action of the carbon dioxide adsorbent begins. Thus, the carbon dioxide gas contained in the rigid urethane foam is easily adsorbed. In this case, the rate of movement of the carbon dioxide gas is determined by the passage of the heat insulating wall of the rigid urethane foam, but since the inside of the package of the carbon dioxide gas adsorbent has a negative pressure, it can be moved in a short time. Further, since the adsorbent is vacuum-packaged and does not contain air, the heat insulating performance of the rigid urethane foam is not deteriorated by releasing air or the like instead of adsorbing carbon dioxide gas.

Examples Hereinafter, the heat insulating box body of the present invention will be described with reference to Examples with reference to FIGS.
It will be described with reference to the drawings. It should be noted that the same components as those of the related art are denoted by the same reference numerals and the description thereof will be omitted.

Reference numeral 7 is a packaging body in which synthetic zeolite as the carbon dioxide adsorbent 8 is vacuum-packaged, and the jacket 9 of the packaging body is a biaxially stretched polystyrene film.

The packaging body 7 is fixed to the back surface of the inner box 3 with an adhesive tape or the like,
A space between the inner box and the outer box 2 is integrally foamed with a hard urethane foam 4 having CFC 11 as a foaming agent to form a heat-insulating box body 1.

The thermal conductivity of the rigid urethane foam decreased from 0.0135 kcal / mhr ° C to 0.0120 kcal / mhr ° C in the heat-insulated box 1 that was dismantled immediately after foaming and that dismantled after 4 weeks. It was found that the heat insulation performance of the box body 1 was improved by about 10%. The thermal conductivity is based on Vacuum Riko Co., Ltd.
It measured using K-MATIC at the average temperature of 24 degreeC.

As described above, it was found that the heat insulating box 1 of the present invention exhibits excellent heat insulating performance. This is because the carbon dioxide gas generated by the residual moisture in the raw material of the rigid urethane foam or the moisture due to the moisture absorption at the time of integral foaming reacting with the isocyanate as the curing agent is filled in the package 7 without remaining in the rigid urethane foam 4. The carbon dioxide gas adsorbent 8 thus adsorbed and removed. During the adsorption process, carbon dioxide gas in the rigid urethane foam 4 is subjected to chemical attack by the foaming agent in the rigid urethane foam and is filled in the package 7 having a negative pressure through the cracks / pinholes formed in the outer cover 9. Since it reaches the carbon dioxide adsorbent 8, its adsorption speed is high. Especially, since the carbon dioxide adsorbent 8 is vacuum-packed,
The carbon dioxide adsorption rate is remarkably high, and the carbon dioxide adsorption does not release a gas having high thermal conductivity such as air.

Although synthetic zeolite is used as the carbon dioxide adsorbent 8 in the examples, metal oxide, metal hydroxide,
Activated carbon, silica gel, etc. are also possible. Although a biaxially stretched polystyrene film is used as the jacket 9, an unstretched polystyrene sheet, a methyl methacrylate sheet or the like may be used. Furthermore, the entire surface of the jacket 9 does not have to be a plastic film that is chemically attacked by a foaming agent, and if there is a surface that does not face the rigid urethane foam,
In that respect, a material inert to the foaming agent can be applied.

EFFECTS OF THE INVENTION As described above, a vacuum package in which a carbon dioxide adsorbent is covered with an outer cover made of a plastic film that dissolves or swells in a fluorocarbon foaming agent is disposed between an inner box and an outer box, and a hard urethane Since the foam is integrally foamed to form a heat-insulating box, the carbon dioxide gas remaining in the rigid urethane foam is negatively affected by cracks and pinholes on the outer cover caused by the chemical attack of the fluorocarbon foaming agent. Since it is adsorbed by the carbon dioxide adsorbent in the package, which is the pressure, its adsorption speed is extremely fast. Also, since gas such as air and water is not released from the carbon dioxide adsorbent, it is not contained in the air bubbles of the rigid urethane foam. As a result, only the gas component of the foaming agent is left, and as a result, the thermal conductivity of the gas in the bubbles is reduced and the thermal conductivity of the rigid urethane foam is improved, providing a heat insulating box with excellent heat insulation performance. It is.

Further, since the inside of the vacuum package is kept in a vacuum unless the outer cover is damaged by contact with the freon-based foaming agent, the carbon dioxide adsorbent does not adsorb air, moisture, etc. . Therefore, even if the rigid urethane foam is placed between the inner box and the outer box and left unfoamed, the heat insulation box body can be provided with extremely good workability without lowering the adsorption performance of the carbon dioxide gas adsorbent. is there.

[Brief description of drawings]

1 is an external perspective view of a heat insulating box body according to an embodiment of the present invention, FIG. 2 is a sectional view of the heat insulating box body, FIG. 3 is an enlarged sectional view of FIG. 2, and FIG. It is sectional drawing of a heat insulation box. 1 ... Insulation box, 2 ... Outer box, 3 ... Inner box, 4 ... Hard urethane foam, 7 ... Package.

Claims (1)

[Claims] 1. A carbon dioxide adsorbent, an outer cover made of a plastic film that dissolves or swells in a fluorocarbon foaming agent, an inner box, an outer box, and a rigid urethane foam filled between the boxes. A heat insulating box body in which a package body in which a carbon dioxide gas adsorbent is vacuum-packaged with the outer cover is arranged between the inner box and the outer box.