JPS58136434A - Heat-insulating structure and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention relates to a vacuum insulation board such as a heat/cold insulation material.

Traditionally, glass fiber has been used as an insulation board for keeping heat and cold.

Asbestos, calcium silicate molded plate 1 foamed polyurethane, foamed polystyrene, etc. are used. Glass fibers and calcium silicate molded plates have good heat resistance, but their thermal conductivity is 0.03 to 0.06 θ/mb+:, and their insulation effect is not very good.

Foamed plastics such as foamed polyurethane and foamed polystyrene are commonly used as low-temperature cold insulation materials for refrigerators, etc. In the case of foamed polyurethane, the thermal conductivity at 24°C reaches 0.015 Kd/m h °C. It is not easy to improve the above heat insulation properties. Furthermore, containers for low-temperature liquefied gases that store liquid oxygen, liquid nitrogen, etc. are composed of double tanks, and powder vacuum insulation is known in which the calibration is vacuum-filled with foamed perlite powder. 0.01 to obtain insulation effect
A vacuum higher than Torr is required, and obtaining this degree of vacuum requires a long vacuum treatment operation, which is not easy to achieve industrially.

The present invention does not require a high vacuum, can be easily manufactured at an industrially easy vacuum level of about 0.1 to 1 Torr, has a thermal conductivity of less than 0.014 mh °C, and has an excellent heat insulation effect. The purpose is to provide a heat insulating board that is lightweight and has good productivity, and its feature is that a plastic molded body with an open pore structure is filled in a vacuum-maintained container.

In the present invention, foamed polyvinyl chloride, foamed polyurethane,
Moldings having open cells such as foamed polyethylene, foamed polypropylene, foamed polystyrene, foamed phenol, and foamed urea 9 foamed epoxy can be used, and it is more desirable to use a foamed material with a porosity of 96 inches or more. Generally, the bulk density of such plastic foam molded products is o, o6y.
It has the advantage of being smaller than /d and extremely lightweight. By filling a plastic molded body with open cells into a container kept in a vacuum, the gas in the voids inside the molded body is degassed and becomes a vacuum, and the heat is absorbed by the convection and heat transfer of the gas. As a result of the decrease in the conductive component, the apparent thermal conductivity decreases, which has the effect of improving the heat insulation performance.

Furthermore, since most of the volume of such molded bodies is void, material costs are low, and molded bodies with complex shapes can be formed using normal plastic foam molding and cutting methods. It has excellent productivity effects.

Another feature of the present invention is that the heat insulating structure is characterized in that a plastic molded article having an open pore structure is filled into a heat-sealable film-like container, and then heat-sealed under vacuum to seal the container. It is a method of manufacturing the body.

When filling and sealing a plastic molded article with a continuous pore structure into a vacuum container, it is necessary to fill the container with the plastic molded article, evacuate the inside of the container, and then seal the opening of the container. As this opening becomes larger, it becomes more difficult to seal it. Particularly in the case of a thick metal container that can withstand vacuum loads, the vacuum sealing method is complicated, resulting in poor productivity. In this regard, when a film-like plastic container that can be heat-sealed and sealed is used, the opening of the film-like plastic container can be easily sealed by heat-sealing the opening of the film-like plastic container in a vacuum container.

In general, film-like plastic films have a softer surface hardness than inorganic molded products such as calcium silicate plates, so when vacuum packaging inorganic foam molded products with film, the film may be scratched and vacuum leaks. However, since the surface hardness of the plastic molded article of the present invention is almost the same as that of a film-shaped plastic container, there is no chance of the film-shaped container being damaged or torn. It has excellent quality and reliability.

There are no particular restrictions on the material for the film-like plastic container, but examples include single-layer or laminate films such as polyethylene, polypropylene, nylon, polyester, polyvinyl alcohol, polyvinylidene chloride, metal-deposited films, and combinations of the above-mentioned films and metal foil. A laminate film etc. can be used.

The present invention will be explained in more detail below with reference to Examples.

In this example, the thermal conductivity was measured using a K-Matic thermal conductivity measuring device manufactured by Dynatic Co., Ltd.
The thermal conductivity at a temperature difference between 13° C. and 35° C. was measured using a method based on M-(+s1s).

Example 1 As shown in FIG. 1, a foamed polyvinyl chloride plate with a specific gravity of o, o6y/cr/l and a continuous porosity of 96 cm was used as a plastic molded body 1 having a continuous pore structure, and this was heat-sealed. A laminate film bag with a thickness of 160 μm made of stretched polypropylene, polyvinyl alcohol, and polyethylene is placed as a possible film-like container 2, and this is placed in a vacuum container equipped with a heat sealing device.
The pressure inside the vacuum container was set to 0.01 and 0.0, respectively. O5, 0
,1,0,5,1.

5.10. Evacuated to a vacuum of 30 and 760 Torr. At this time, the inside of the film bag filled with the foamed polyvinyl chloride board has the same degree of vacuum as the inside of the vacuum container. With the vacuum container and the inside of the film bag filled with foamed polyvinyl chloride board kept at the same vacuum, the open opening of the film bag is heat-pressed using a heat sealing device to seal the film. Seal the bag. Next, after introducing outside air into the vacuum container and returning it to atmospheric pressure (760 Torr), the film bags filled with foamed polyvinyl chloride plates were taken out and each of A vacuum insulation board was obtained.

The obtained film bag of each vacuum insulation board was strongly attracted to the foamed polyvinyl chloride board inside, and the vacuum seal was perfect.

In addition, the results of measuring the thermal conductivity of each vacuum insulation board, the thermal conductivity after 10 days, etc. are shown in Table 1 and Figure 2, and the thermal conductivity at a vacuum degree of I Torr is 0. 01/i=4/mh°C or less, and it is clear that the heat insulation effect is excellent.

(Left below) 9P In contrast to this, a vacuum insulation board was prototyped using the same method as above using a calcium silicate board, which is a molded body of inorganic material with continuous pores, and the results are shown in Table 1 and Figure 2. As shown in G,
In order to make the thermal conductivity less than 0.01-mh°C, it is necessary to make the degree of vacuum less than 0.06 Torr.

Example 2 Specific gravity o, oa! ? //crI, 160μ thick foamed polyurethane with continuous porosity of 100%, made of aluminum-deposited polyester, polyvinyl alcohol, and polypropylene
Place it in a laminated bag with a size of
Vacuum insulation plates of 8 cIrL and thickness 3 (1 m) with different degrees of vacuum were obtained.

The results of measuring the thermal conductivity of each obtained vacuum insulation board and the thermal conductivity after 10 days are shown in Table 1 and Figure 2 B. The thermal conductivity at a vacuum degree of 1'rorr is It is 0.01 Wmh°C or less, and it is clear that the heat insulation effect is excellent.

As explained above, the present invention uses 10
- It is a heat insulating structure in which a container is filled with a plastic molded body having a continuous pore structure, and after the plastic molded body having a continuous pore structure is filled into a film-like container that can be heat-sealed, it is placed under vacuum. The heat-sealing structure is manufactured by heat fusion and sealing, and the thermal conductivity is 0.01 Wm.
Vacuum insulation board with excellent insulation effect below h℃ can be manufactured at industrially easy 0.1 to 1 Torr without requiring high vacuum.
It can be manufactured with a degree of vacuum, and the specific gravity is 0.0.
It is possible to use a foamed plastic molded product with a rating of 5 f/cdt or less, which makes it very lightweight, requires very little raw material, has a resource saving effect, and is inexpensive. Furthermore, molded bodies with complex shapes can be easily formed. Furthermore, it has the advantage that it does not damage film-like plastic containers that are relatively soft and easily scratched, and that it is possible to obtain a vacuum heat insulating board that has a long empty storage life.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a vacuum insulation structure according to an embodiment of the present invention;
Figure 2 is a graph showing the relationship between the degree of vacuum and thermal conductivity of the same heat insulating structure.
C shows the characteristics when a foamed polyurethane molded body is used, and C shows the characteristics when a calcium silicate molded body is used as a comparative example. 1...Plastic molded body, 2...River/container.

Claims (2)

[Claims] (1) A heat insulating structure in which a container kept in vacuum is filled with a plastic molded body having an open pore structure. (2) After filling a plastic molded article with an open pore structure into a film-like plastic container that can be heat-sealed,
A method for manufacturing heat insulating structures that is sealed by heat fusion under vacuum.