JPH0611247A - Heat insulating body and heat insulating wall - Google Patents

Abstract

PURPOSE:To maintain and ensure an excellent heat insulating capability for a long period of time by improving the capability of a carbon dioxide adsorbing substance of the adsorbent for a heat insulating body of which the inside is decompressed and sealed. CONSTITUTION:A heat insulating body 5 of which the inside is decompressed and sealed is provided by making a hard polyurethane foam with an open cell structure as a core, and covering an adsorbent 6 which contains at least an alumina compound with carbonic ions in the molecular structure as an adsorbing substance, by a covering material 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulator used for a refrigerator, a freezing prefab, etc., and a heat insulating wall using the heat insulator.

[0002]

2. Description of the Related Art Recently, in order to improve the heat insulating performance of a heat insulating box, attention has been paid to the use of a heat insulating body having a reduced pressure inside. As this heat insulator, for example, Japanese Patent Laid-Open No. 63-1728.
As disclosed in Japanese Patent Laid-Open No. 78, there is proposed a one in which a rigid urethane foam having open cells is used as a core material and is vacuum-sealed together with an adsorbent containing various adsorbents.

This Japanese Patent Application Laid-Open No. 63-172878 will be described with reference to FIG. 3. In the figure, reference numeral 1 is a heat insulator, and a hard urethane foam 2 having open cells is covered with a metal-plastic film 3 to form an adsorbent. 4 and the inside are decompressed and sealed. The adsorbent 4 is composed of activated carbon as an organic gas adsorbing substance, metal hydroxide as a carbon dioxide adsorbing substance, and metal chloride as a moisture adsorbing substance.

[0004]

However, in the heat insulator 1 as described above, the rigid urethane foam having the open cells as the core material is the carbonic acid produced by the reaction of the raw material isocyanate with the moisture. Since a trace amount of gas is contained in the urethane resin, it has been a basic problem that the heat insulating performance is deteriorated due to the increase of the internal pressure by diffusing into the inside of the heat insulator over time. Therefore, it is necessary to add a carbon dioxide adsorbing substance, but when a metal hydroxide is used as the carbon dioxide adsorbing substance, as in the above-mentioned JP-A-63-172878, water is generated in the reaction with carbon dioxide. As a result, it was necessary to newly add a water adsorbing substance, which was a big problem in terms of efficiency and reliability. Further, synthetic zeolite containing silica-alumina as a component is a typical adsorbent as a carbon dioxide adsorbing substance.
As described in Japanese Patent No. 72878, there is a problem in that carbon dioxide adsorption is not sufficiently exhibited in a coexisting gas system of carbon dioxide and moisture because adsorption activity with moisture is preferentially performed due to its high adsorption activity with moisture. there were. Therefore, there has been a problem to apply a carbon dioxide adsorbing substance that is not easily affected by other coexisting gases and that does not release a new gas by an adsorption reaction.

In view of the above problems, the present invention is not limited to adsorbing a small amount of carbon dioxide gas generated from an internal constituent material or invading from the outside in a heat insulating body having a vacuum sealed inside. That is, it is an object of the present invention to prevent the rise of internal pressure by applying an adsorbent that does not generate a new gas due to a secondary reaction with carbon dioxide, and to provide a heat insulator with no deterioration in heat insulating performance. .

[0006]

In order to solve the above-mentioned problems, the present invention is directed to an adsorption containing a core material made of a rigid urethane foam having an open-cell structure and an alumina compound having at least carbonate ion in the molecular structure as an adsorbent. The body and the body are covered with a covering material, and the inside is vacuum-sealed to obtain a heat insulator.

A core material made of an inorganic porous material such as pearlite powder, and at least the adsorbent material as defined in claim 1
An adsorbent containing an alumina compound having a carbonate ion in the molecular structure as described above is covered with a jacket material and a heat-insulating body whose inside is decompressed and sealed is embedded in a hard urethane foam heat-insulating material to obtain a heat-insulating wall. It is a thing.

[0008]

With the above structure, the carbon dioxide gas generated over time from the rigid urethane foam having the open cell structure as the core material is efficiently adsorbed and removed by the carbon dioxide gas adsorbing material composed of the alumina compound having carbonate ions in its molecular structure. It Also,
Even with a heat insulator that uses an inorganic porous material such as pearlite powder as a core material that does not generate internally, the carbon dioxide gas that invades through the outer covering material when embedded in a hard urethane foam heat insulating material has carbonate ions in its molecular structure. It is easily adsorbed on the carbon dioxide adsorbing substance composed of an alumina compound. Of course, the same effect can be obtained when a heat insulating body having a core material made of hard urethane foam having an open cell structure is embedded in the hard urethane foam heat insulating material.

Since an alumina compound having a carbonate ion in its molecular structure has a high selective adsorption capacity for carbon dioxide gas and little influence of water, it adheres to a rigid urethane foam having an open cell structure or an inorganic porous material. Even when the trace amount of water is present as a gas in the heat insulator, the carbon dioxide gas can be efficiently adsorbed, and another gas is not generated and generated during the adsorption. Therefore, the addition amount of the moisture adsorbing substance can be significantly reduced, the internal pressure of the heat insulating body does not rise, and the initial excellent heat insulating performance can be obtained for a long period of time.

[0010]

EXAMPLES A method for manufacturing a heat insulating body of the present invention will be described below with reference to FIGS. It should be noted that the same components as those of the conventional one are designated by the same reference numerals and the description thereof will be omitted.

Reference numeral 5 is a heat insulator, and a hard urethane foam 2 having an open-cell structure having a width and depth of 30 cm and a height of 2 cm and an adsorbent 6 are covered with a jacket material 3 made of a metal-plastic film. , The inside is vacuum sealed. Adsorbent 6
Adds activated carbon as an organic gas adsorbing substance, an alumina compound having a carbonate ion in the molecular structure as shown in Chemical formula 1 as a carbon dioxide adsorbing substance, and calcium chloride as a moisture adsorbing substance.

[0012]

[Chemical 1]

The adsorbent 6 is filled in a bag 7 made of non-woven paper in advance. Table 1 shows the initial thermal conductivity of the heat insulator 5 when the adsorbent 6 is applied and the thermal conductivity after 30 days have elapsed.

[0014]

[Table 1]

Reference numeral 8 is a heat insulating wall composed of a heat insulating body 9 and a hard urethane foam heat insulating material 10. The heat insulator 9 is made of pearlite powder 11 as a core material, is covered with the adsorbent 6 by the jacket material 3, and is hermetically sealed under reduced pressure. Table 2 shows the initial thermal conductivity of the heat insulating wall 8 when the heat insulator 9 is used and the heat conductivity after 30 days have passed.

[0016]

[Table 2]

As a comparative example, when calcium hydroxide is used as a carbon dioxide gas adsorbing material and the amount of calcium chloride added as a water adsorbing material is changed, the initial thermal conductivity of the heat insulator 5 and the thermal conductivity after 30 days have passed. Rate, and the initial thermal conductivity of the heat insulator 1 when a carbon dioxide gas adsorbing substance is not used and after 30 days, further as a carbon dioxide gas adsorbing substance (Chemical formula 2)
The initial thermal conductivity and the thermal conductivity after 30 days of aging are shown in Table 1 when an alumina compound having no such carbonate ion in the molecular structure is used.

[0018]

[Chemical 2]

Further, as a comparative example, initial heat conduction of the heat insulating wall 8 in which the heat insulating body 9 is embedded when an alumina compound such as (Chemical Formula 2) which does not contain carbonate ion in the molecular structure is used as the carbon dioxide adsorbing substance. The rate and the thermal conductivity after 30 days are also shown in (Table 2).

When an alumina compound having a carbonate ion in its molecular structure is used as a carbon dioxide gas adsorbing substance as described above, the carbon dioxide gas generated from the core material of the heat insulator 5 is adsorbed and removed by the selective carbon dioxide gas adsorbing power. Therefore, there is little deterioration of heat insulation performance due to the increase of internal pressure, and it is possible to maintain and secure the quality for a long time. Further, when calcium hydroxide is used as the carbon dioxide gas adsorbing substance as in the comparative example, a large amount of calcium chloride, which is the water adsorbing substance, must be added to remove the water produced by the reaction, which is problematic in terms of efficiency. Is.

Similarly, a heat insulating body 9 having a core material of pearlite powder 11 is used as a heat insulating wall 8 made of a hard urethane foam heat insulating material 10.
When buried in, the carbon dioxide gas that invades through the jacket material 3 is adsorbed and removed by the alumina compound having a carbonate ion in its molecular structure by the selective carbon dioxide gas adsorption force inside the heat insulator 9. There is little deterioration of heat insulation performance due to the increase of pressure, and it is possible to maintain and secure quality for a long time.

It should be noted that the mechanism has not been clarified as to whether the adsorption force of carbon dioxide gas is increased when the carbonate compound is included in the molecular structure of the alumina compound, but the presence of carbonate ion increases the affinity with carbon dioxide gas. It is considered that the adsorption of the crystals into the micropores is facilitated.

[0023]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a core material made of a rigid urethane foam having an open-cell structure and an adsorbent containing an alumina compound having at least carbonate ion in the molecular structure as an adsorbent material are used as a jacket material. Since it is a heat-insulating body that is enveloped in and sealed inside under reduced pressure, the alumina compound that has carbonate ions in its molecular structure selectively adsorbs the carbon dioxide gas generated inside to prevent the rise of internal pressure, and thus the heat insulation performance. It is possible to maintain and secure for a long time.

Further, a core material made of an inorganic porous material such as pearlite powder and an adsorbent containing an alumina compound having at least carbonate ions in its molecular structure as an adsorbent are coated with a jacket material to reduce the pressure inside. Even if the carbon dioxide gas present in the rigid urethane foam insulation enters the inside of the insulation through the jacket material, the sealed insulation is embedded in the rigid urethane foam insulation to form the heat insulation wall. An alumina compound having carbonate ions in its molecular structure is selectively adsorbed to prevent an increase in internal pressure, so that it is possible to maintain and secure the heat insulating performance for a long period of time.

As described above, since the heat insulating performance of the heat insulating body and the heat insulating wall can be maintained for a long period of time, it is possible to contribute to energy saving.

[Brief description of drawings]

FIG. 1 is a sectional view of a heat insulator according to an embodiment of the present invention.

FIG. 2 is a sectional view of a heat insulating wall according to an embodiment of the present invention.

FIG. 3 is a sectional view of a conventional heat insulator.

[Explanation of symbols]

 2 Rigid urethane foam having an open cell structure 3 Outer coating material 5 Heat insulating material 6 Adsorbent material 8 Heat insulating wall 9 Heat insulating material 10 Hard urethane foam heat insulating material 11 Perlite powder

Claims (2)

[Claims] 1. A core material made of a rigid urethane foam having an open-cell structure and an adsorbent containing an alumina compound having at least carbonate ions in its molecular structure as an adsorbent are covered with a covering material, and the inside is vacuum-sealed. Insulation. 2. A core material made of an inorganic porous material such as pearlite powder, and an adsorbent containing an alumina compound having at least carbonate ions in its molecular structure as an adsorbent are covered with a jacket material, and the inside pressure is reduced. A heat insulation wall in which a sealed heat insulator is embedded in a rigid urethane foam insulation material.