JPS608399B2 - insulation board - Google Patents

Description

[Detailed description of the invention] The present invention relates to a powder vacuum insulation board.

Conventionally, glass-woven rock wire, foamed polyurethane, and the like have been used as insulation boards for heat and cold insulation. Glass fiber and rock wool have good heat resistance, but their thermal conductivity is 0.
03 to 0.05 kcal/wh°C, and the heat insulation effect is not very good. In addition, foamed resins such as foamed polyurethane and foamed polystyrene are commonly used as low-temperature cold insulation materials for refrigerators and the like. It is not easy to improve the insulation properties further than this.The same is true for expanded polystyrene.Furthermore, as a cold insulation board for liquefied petroleum gas tanks and liquid nitrogen tanks, it is difficult to improve the insulation properties further. A powder vacuum insulation board is known in which the gaps are vacuum-filled with foamed perlite powder with an average particle size of 100 to 300 mA. 0.01Ton to obtain insulation effect
A higher vacuum is required, and it is not easy to achieve this degree of vacuum industrially. The evacuation capacity of a large Kinney-type single-stage oil rotary vacuum pump commonly used in industry decreases in evacuation speed as the degree of vacuum increases. For example, in a commercially available oil rotary pump, the pumping speed suddenly decreases from around 0.05 Ton. In this way to. It takes a considerable amount of time to achieve a degree of vacuum of 0.1 ton, which is disadvantageous from an industrial standpoint. The present invention relates to a powder vacuum insulation board that eliminates the above drawbacks, does not require a high vacuum, can be easily manufactured at an industrially easy degree of vacuum of about 0.1 to ITom, and has a high thermal conductivity. is 0.01kc
The purpose of this is to provide an inexpensive heat insulating board that is smaller than al/h°C and has an excellent heat insulating effect. It is characterized by being filled with pulverized powder.

One of the features of the present invention is the use of pulverized foamed pearlite powder with an average particle size of 50 microns or less. Generally, the thermal conductivity when powder is filled in a container kept in vacuum varies depending on the degree of vacuum, but foamed perlite, which is known for powder vacuum insulation, has a hollow spherical shell shape. The average particle size is about 100 to 150 French, and when this powder is used, the thermal conductivity of Iton under vacuum is about 0.0 water cal'hoC at 2400.
On the other hand, as a result of various studies, we found that by destroying the hollow spherical shell state and using pulverized foamed pearlite powder with an average particle size of 50 Buddhas or less, the thermal conductivity under the vacuum of ITorr could be reduced to 0.01 kcal. It has been discovered that the heat insulating properties are improved by reducing the temperature to /skin h°C or lower. In the present invention, the pulverized powder of expanded pearlite is defined as ``a hollow spherical expanded pearlite obtained by crushing naturally occurring pearlite or obsidian to a certain particle size, rapidly heating and expanding it, and then finely pulverizing the expanded pearlite. It is possible to use a powder having an average particle size of 50 or less and having a chemical composition of 70% to 80% Si0 and 10% to 20% Si203 as the main component.

The shape of the crushed expanded pearlite powder obtained in this way is a flake shape similar to the fragments obtained by breaking the shell of a chicken egg, and when the powder is aggregated, the contact area of the flake powder is very small. , the cage becomes high due to an increase in porosity, etc., and has the effect of providing excellent heat insulation properties even at a relatively low degree of vacuum.

FIG. 1 shows a comparison of representative shapes of a known foamed perlite powder A for powder vacuum insulation and a pulverized foamed perlite powder B of the present invention.

Foamed/f-light pulverized powder with an average particle size of 50 degrees or less is
Since the bulk specific gravity is 4.0, it is difficult to fill the container tightly.

On the other hand, when a deformable film-like plastic container is used, when the inside of the container is sealed in a vacuum state, the pressure difference between the inside and outside of the vacuum container causes the film to be strongly attracted toward the inside, making it tightly adhered. do. As a result, the packing density of the powder increases, which has the effect of increasing mechanical strength. There are no particular restrictions on the material for film-like plastic containers, but examples include single-layer or laminate films of polyethylene, polypropylene, nylon to polyester, polyvinyl alcohol, polyvinyl chloride, polyethylene copolymers, aluminum vapor-deposited films, and "A laminate film of the above film and aluminum foil can be used.

FIG. 2 is a sectional view showing the basic structure of an embodiment of the heat insulating material of the present invention.

In FIG. 2, 1 is a foamed perlite pulverized powder, 2 is a film-like plastic container, and the space inside the container 2 is maintained at a vacuum of 0.1 to Iton.

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 Darinatech.
The thermal conductivity at a temperature difference between 13° C. and 35° C. was measured by a method based on TM-C518.

Example 1 The average particle diameter as shown in Table 1 is
Pulverized foamed perlite powders A, B, C, and D with loAm of 3 mm, loAm, 15 μm, and 40 μm, and known expanded perlite powder E of 300 μm, each with an average particle size of 110 μm.
, F were filled into kraft paper bags, and then placed into a three-layer laminate film bag made of polyester, polyvinyl alcohol, and polyethylene, and then placed in a vacuum container equipped with a heat sealing device (inner volume 50) After placing the film bag inside the oil rotary pump (exhaust capacity)
500 som/min) to increase the pressure inside the vacuum vessel to o. o5Ton, o. ITom, o. 3rorr,
It was evacuated to a vacuum of 5Ton, 1 orr, 30Tom and 76 orr.

At this time, the inside of the film bag filled with expanded perlite powder will have the same degree of vacuum as the inside of the vacuum container.In this way,
While the vacuum container and the inside of the film bag filled with powder were maintained in a vacuum, the open portion of the film bag was pressed and heated using a heat sealing device to seal the film bag. Next, outside air is introduced into the vacuum container to bring it to atmospheric pressure (760 Torr).
After returning to the room temperature, the film bag filled with expanded perlite powder was taken out to obtain powder vacuum insulation boards each having a width of 28 degrees, a length of 28 arcs, and a thickness of 3 skins. It was confirmed that the obtained film bag of each powder vacuum insulation board was strongly attracted to the powder filled inside and adhered tightly to the powder, and the vacuum sealing was complete.

The time required to make the inside of the container a vacuum of ITorr, 0.1 Tom, and 0.05 Tom is 19 seconds, respectively.
It was 39 seconds and 60 current sand. The results of measuring the thermal conductivity, thermal conductivity after 10 days, specific gravity, etc. of each obtained powder vacuum insulation board are shown in Table 2 and Figure 3. Powder vacuum insulation board using pearlite pulverized powder (sample numbers A, B, C)
, D), the heat conductivity at the vacuum degree of ITom is 0.
It is clear that the thermal conductivity decreases as the average particle size of the powder decreases, and the heat insulation effect is excellent.

On the other hand, when using ordinary, well-known foamed perlite powder for vacuum insulation (sample numbers E, *F), the degree of vacuum must be 0.05 or less in order to reduce the thermal conductivity to 0.01 kcal/whoC or less. I know what I need to do. Table 1 Table 2 Example 2 Average particle size: 3 mounds of foamed/glazed crushed powder (Example 1)
Fill a breathable cloth bag with the powder type A) used in
polyester, polypropylene, polyvinylidene chloride,
Each sample was placed in a multilayer laminate film bag made of aluminum foil, aluminum vapor-deposited film, etc., and a powder vacuum insulation board with a width of 28 cm, a height of 28 cm, and a thickness of 3 cm was manufactured using the same method as in Example 1. .

The appearance of the obtained powder vacuum insulation boards was such that the film bag was strongly attracted to the internally filled powder, was in close contact with the pulverized powder, and was completely vacuum-sealed.

Table 3 shows the manufacturing process conditions and properties of the obtained heat insulating plates for each case. As is clear from Table 3, the thermal conductivities were all below 0.01 kcaVmHC, indicating good heat insulation properties, and when the thermal conductivities were measured after 10 days, ``No significant change over time was observed. It was confirmed that the vacuum seal was complete.

In addition, the specific gravity of the obtained heat insulating board was 0.35 to 0.36 ta'
Compared to the specific gravity of 0.065 ta's before vacuum sealing, it is compressed and packed quite densely.

As explained above, the present invention provides a heat insulating board in which a container kept in vacuum is filled with pulverized foamed perlite powder having an average particle size of 50 μm or less, and does not require high vacuum. "The thermal conductivity of the kite at a vacuum level of Iton, which is easy to obtain industrially, is 0.01 kcaV h.

It is industrially valuable because it is smaller than C and has an excellent heat insulating effect, and because it is made of a film-like plastic container, it has the effect of providing strong mechanical strength.

[Brief explanation of the drawing]

Figure 1A is a typical shape diagram of a known foamed perlite powder for powder vacuum insulation; Figure 1B is a typical shape diagram of the foamed perlite pulverized powder of the present invention; Figure 2 is the basic shape of the heat insulation board of the present invention. Fig. 3 is a curve diagram showing the relationship between the degree of vacuum and the thermal conductivity of the heat insulating board according to the example of the present invention.・・・・・・Container. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A heat insulating board in which a container maintained in vacuum is filled with pulverized foamed perlite powder having an average particle size of 50 μm or less. 2. The heat insulating plate according to claim 1, wherein the degree of vacuum is 0.1 to 1 Torr. 3. The heat insulating plate according to claim 1, wherein the container kept in vacuum is a film-like plastic container.