JPH0323825B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat insulating material pack used for heat insulating walls of heat insulating boxes such as refrigerators, freezers, and storage cases.

Structure of the conventional example and its problems FIGS. 1 to 3 show a conventional heat insulating material pack. The configuration of this conventional example will be explained below with reference to FIGS. 1 to 3.

In the figure, 1 is a vacuum insulation pack;
A breathable inner bag 2 is filled with a filler material 3, and the inner bag 2 is covered with a container 4 made of a laminate film, and the inside pressure is reduced to 0.01 Torr.
The filler 3 is a closed cell powder 3a such as expanded perlite, or a pulverized powder 3 such as expanded perlite.
Powder such as b was used. In the case of a closed cell powder 3a, the powder is a hollow spherical closed cell as shown in FIG. 2, and a gas 5 such as air or water vapor is encapsulated in a hollow portion 6 of the powder. In addition, in the case of the pulverized powder as the powder 3, it has a flaky or acicular shape as shown in FIG.

However, in such a product, if the insulation material pack 1 is obtained by vacuum packaging using closed cell powder 3a such as expanded perlite as the filler 3 in a vacuum container (not shown), the pressure difference between the inside and outside causes As a result, the heat insulating material pack 1 is compressed.

However, only the atmospheric pressure difference is applied to the wall of the closed cell powder 3a, and the closed cell powder 3a inside the insulation pack 1
It is difficult for all the bubbles to break, and the gas 5 contained in the hollow part 6 cannot be sufficiently degassed during vacuum degassing, and after vacuum packaging, the closed cell powder 3a is compressed due to the atmospheric pressure difference. It ruptures, generates foam-broken powder, and gas 5 fills the insulation material pack 1, causing the degree of vacuum in the insulation material pack 1 to decrease over time.
The drawback was that the thermal conductivity decreased only to about 0.010 Kcal/mh°C. In addition, in the case of pulverized powder 3b such as expanded pearlite as the filler 3, there is no deterioration in the degree of vacuum due to bubble breakage because there are no closed cells.
A low thermal conductivity of 0.0055 Kcal/mh°C can be obtained, but the density of the insulation pack 1 is 0.2 to 0.3.
It is heavy in terms of weight (g/cc), and its use as a heat insulating material has drawbacks such as workability and structural reinforcement.

OBJECTS OF THE INVENTION The present invention eliminates the drawbacks of the above-mentioned conventional examples, and aims to provide a heat insulating material pack that is lightweight and has excellent heat insulation properties.

Composition of the Invention In order to achieve the above object, the present invention vacuum-packs a powder having closed cells, then breaks the foam to produce a spherical-shaped broken powder, and vacuum-packages the powder again. It has both the light weight of closed cell powder and the good heat insulation performance of pulverized powder.

DESCRIPTION OF THE EMBODIMENTS The configuration of an embodiment of the present invention will be described below with reference to FIG. 4, or the same components as those of the prior art will be given the same reference numerals and detailed explanation thereof will be omitted.

In the figure, reference numeral 7 denotes a heat insulating material pack, which includes a filling 9 made of a spherical-shaped foamed pearlite broken powder 8, a breathable inner bag 2 containing the filling, and a plastic laminate film wrapped around the outer periphery of the filling 9. It is formed by a closed container 4 consisting of.

In manufacturing the heat insulating material pack 7, first, closed cell powder 3a such as expanded perlite is filled into the inner bag 2 and sealed, and then one end is opened and placed in the container 4, and the inside is filled with 1×10 ^- One end of the container 4 is heat-sealed while maintaining a vacuum level of about ² Torr. Then, the container 4 is vacuum-sealed under atmospheric pressure and left to stand, and the container 4 is compressed due to the pressure difference with the atmospheric pressure, thereby straining the closed-cell powder 3a such as expanded perlite.

As a result, the pressure difference between the pressure of the gas 5 in the closed-cell powder 3a and the reduced pressure of the heat insulating material pack 7 causes the closed-cell powder 3a to be locally fractured at 8 as shown in FIG.
The foam-breaking powder 3a' is provided with the following. In addition,
At this time, the foamed powder 8 of the foamed pearlite that has been broken is not flaky or acicular like when it is mechanically pulverized, but maintains a shape close to a spherical shape 9 as shown in FIG. 5. Next, one end of the container 4 is opened, vacuum deaerated to 1×10 ^-2 Torr again, and one end of the container 4 is heat-sealed to obtain a vacuum heat insulating material pack 7.

In the heat insulating material pack 7 manufactured in this manner, the foamed perlite foam-broken powder 3a' which is the filler is not a closed cell and maintains a shape close to the spherical shape 9. Therefore, even after vacuum packaging, there is no gas and the initial degree of vacuum is maintained, resulting in a low thermal conductivity of 0.0060 Kcal/mh℃ and a lightweight density of about 0.12 to 0.22 g/cc. be. In addition, since the particle size is larger than when using pulverized powder 3b such as foamed perlite, there is no need to use a fine-mesh inner bag 2, improving air permeability, shortening the vacuuming time, and improving the manufacturing process. It is possible to rationalize this.

Effects of the Invention The present invention has the above-described configuration, and the following effects can be obtained.

(a) A closed-cell powder such as expanded pearlite is vacuum-packaged to produce a broken-cell powder that is broken while maintaining its spherical shape, and this broken-cell powder is vacuum-packaged. In addition to achieving a weight reduction close to the density of the reduced-pressure heat insulating material pack obtained using this method, the poor thermal conductivity due to the diffusion of residual gas in the hollow portion of the closed cell, which was a drawback in this case, is improved.

(b) Since the particle size of broken powder is larger than that of pulverized powder, open-mesh bags can be used, which improves air permeability and shortens the vacuum degassing time, streamlining the manufacturing process.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional heat insulating material pack, Fig. 2 is a perspective view showing an example of the filler material shown in Fig. 1, and Fig.
The figure is a perspective view showing another embodiment of the filler shown in FIG.
FIG. 4 is a sectional view showing one embodiment of the present invention, and FIG. 5 is a perspective view of the filler shown in FIG. 4. 4... Container, 8... Broken powder, 10... Fractured surface,
11...Spherical shape.

Claims (1)

[Claims] 1 Powder with closed cells such as expanded perlite is packaged under reduced pressure to produce a spherical and broken foam powder, and this broken foam powder is covered with a container made of a laminate film such as metal foil and plastics, and the inside is sealed. Insulation pack with reduced pressure.