JPH0816577B2 - Insulated 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 a rigid urethane foam, which is a typical foamed heat insulating material, various kinds of materials such as polyether polyol and isocyanate used as the main raw materials, a foam stabilizer, a catalyst, and a foaming agent used as the auxiliary raw material can be obtained from the viewpoint of raw materials. Improvement efforts are being made. In such an approach, in order to reduce the thermal conductivity of the rigid urethane foam, it is important to improve the gas thermal conductivity of the gas component in the bubbles. In particular, trichlorofluoromethane (hereinafter referred to as R- It was essential to fill the foam cells with R-11 gas.

However, it is possible to avoid the phenomenon that the moisture contained in the raw material system reacts with the isocyanate due to the residual moisture in the urethane foam raw material or the 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. There wasn't. The gas thermal conductivity of R-11 is 0.0067 Kcal / mhr ° C, whereas the gas thermal conductivity of carbon dioxide is 0.0125 Kcal / mhr ° C.
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. The description of JP-B-53-36297 is characterized in that carbon dioxide gas generated from coffee beans filled in a closed container is adsorbed and removed by the molecular sieves enclosed in the 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. In the case of a rigid 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. Explaining in FIG. 3, reference numeral 1 is a heat-insulating box, which is composed of an outer box 2 made of an iron plate, a plastic inner box 3, and a rigid urethane foam 4 integrally foamed between the outer box 2 and the inner box 3. ing. 5 is molecular sieves (Toyo Soda 9F) filled in a breathable bag 6,
It is arranged in advance between the outer box 2 and the inner box 3 and integrally foamed.

In such a structure, there is a phenomenon that carbon dioxide gas contained in the bubbles is blocked by the bubble film of the rigid urethane foam 4 which is a closed cell, the diffusion speed is slow, and it does not easily reach the molecular sieves 5. It was For this reason,
During the period from the manufacture of the heat insulating box 1 to the actual use, the carbon dioxide gas could not be completely adsorbed, so that the thermal conductivity of the rigid urethane foam 4 could not be sufficiently improved and the heat insulating performance of the heat insulating box 1 could not be improved. .

In view of the above problems, it is an object of the present invention to adsorb and remove carbon dioxide gas contained in a rigid urethane foam in a short time, improve the thermal conductivity of the rigid urethane foam, and improve the heat insulation performance.

Means for Solving the Problems In order to solve the above problems, the present invention provides an insulating box body filled with hard urethane foam between an inner box containing a carbon dioxide adsorbent and a molded body and an outer box. To form.

Action With the above configuration, carbon dioxide gas contained in the rigid urethane foam moves in the thickness direction of the heat insulating wall and is easily adsorbed by the carbon dioxide gas adsorbent impregnated in the inner box. In this case, the rate of movement of the carbon dioxide gas is determined by the passage of the heat insulating wall of the hard urethane foam, but the movement distance is short in the wall thickness direction, so that the carbon dioxide gas can move in a short time. Therefore, carbon dioxide gas existing in the rigid urethane foam can be easily removed by the adsorbent.

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

7 is 5 wt% calcium hydroxide as a carbon dioxide adsorbent
% Is an ABS inner box. Inner box 7 and outer box 2
The spaces are integrally foamed to form the heat insulating box 1.

The heat-insulating box 1 obtained was dismantled immediately after foaming, and 4
When dismantled after a week, the thermal conductivity of the rigid urethane foam 4 has decreased from 0.0134 Kcal / mhr ° C to 0.0122 Kcal / mhr ° C, indicating that the heat insulation performance of the heat insulation box 1 has improved by about 10%. understood. The thermal conductivity was measured at an average temperature of 24 ° C. using K-Matic manufactured by Vacuum Riko Co., Ltd.

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 residual water in the rigid urethane foam raw material or the moisture due to moisture absorption during integral foaming reacts with the isocyanate, which is the curing agent, and carbon dioxide gas generated in the inner box does not remain in the rigid urethane foam 4. It is shown that it was adsorbed by the calcium hydroxide and removed. During the adsorption process, the carbon dioxide gas in the hard urethane foam 4 diffuses and moves in the thickness direction of the heat insulating wall to reach the calcium hydroxide impregnated in the inner box 7, so that the adsorption speed is high. In particular, the diffusion movement of the three layers of the rigid urethane foam, which is a closed-cell body having an adsorption rate that is rate-determining, is short in distance, so that it can be moved and removed in a short time.

EFFECTS OF THE INVENTION As described above, since the inner box and the outer box containing the carbon dioxide adsorbent are molded integrally with the rigid urethane foam to form the heat-insulating box body, it is generated and remains in the rigid urethane foam. Carbon dioxide can be easily removed by adsorption. As a result, the gas thermal conductivity in the bubbles is reduced, the thermal conductivity of the rigid urethane foam is improved, and a heat insulating box having excellent heat insulating performance can be provided.

[Brief description of drawings]

FIG. 1 is an external perspective view of a heat insulating box according to an embodiment of the present invention,
FIG. 2 is a cross-sectional view of the same heat-insulating box, and FIG. 3 is a cross-sectional view of a conventional heat-insulating box. 1 ... Insulation box, 2 ... Outer box, 4 ... Hard urethane foam, 7 ... Inner box.

Claims (2)

[Claims] 1. A molded inner box containing a carbon dioxide gas adsorbent,
A heat-insulating box body consisting of an outer box and a hard urethane foam filled between both boxes. 2. A zeolite as the carbon dioxide adsorbent,
The heat insulating box according to claim 1, which uses an adsorbent such as activated carbon, metal oxide, or metal hydroxide.