JPS61272139A - Heat-insulating film and heat-insulating panel - 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] [Industrial application field] The present invention relates to a heat insulating film and a heat insulating panel.

More specifically, the present invention relates to a heat insulating panel used for walls of electrical appliances such as refrigerators and frozen warehouses, and a heat insulating film used for this heat insulating panel.

[Conventional examples and their problems]

Traditionally, glass fiber has been used as a material with insulation effects.

Inorganic materials such as asbestos and perlite, and organic materials such as foamed polyurethane and foamed polystyrene are known. In addition, rigid polyurethane foam is generally used as a low-temperature insulation material, and it alone has 0, o 15 kcal'
Thermal conductivity h'-/mh'C has been achieved, but it is not easy to further improve the heat insulation performance.

Furthermore, as a cold insulating material for extremely low temperatures such as i-nitrogen containers and refrigerators, a powder vacuum insulation method is known in which the gaps in a double-walled container are filled with foamed perlite and the like is evacuated to a high vacuum. 075 kca! In order to obtain a thermal conductivity of /mh °C or less, it is necessary to evacuate the internal pressure to a high vacuum of 0.01 torr or less. Applying such a high vacuum to a container involves technical and economic problems, requiring an ultra-high-performance vacuum pump and special equipment that completely prevents air leaks.

Therefore, in recent years, in order to solve the above problem, aluminum (A, 6) is used for plastic films.
Packaging materials such as 1-foamed perlite laminated with i or AA vapor-deposited are used, which are sealed and packaged under high vacuum. At this time, the plastic film serves to seal the packaging materials together, and the A[foil and A[vapor-deposited layer] reflect radiant heat and are used to maintain a high vacuum inside for a long period of time.

However, laminate films that have undergone A-6 foil or vapor deposition have a high thermal conductivity of the film itself,
To obtain a heat insulating material with the desired thermal conductivity, 0.0
It was necessary to maintain a high vacuum of 1 torr or less, and as mentioned above, very advanced technology was required.

[Purpose of the invention]

An object of the present invention is to provide a heat insulating panel that does not require a high vacuum of 0.01 torr or less and has a lower thermal conductivity, and a heat insulating film for use in this heat insulating panel.

[Summary of the invention]

In order to achieve this object, the present invention has a thermal conductivity of 100
A heat insulating film made of a plastic film provided with a thin layer of metal or alloy of kcal/mh・°C or less,
To provide a heat insulating panel characterized in that a lightweight, porous inorganic powder such as 1-foamed perlite is sealed and packaged under vacuum using this heat insulating film.

[Detailed description of the invention]

Examples of the plastic film according to the present invention include general-purpose films such as biaxially oriented polypropylene, nylon 5 polycarbonate, and polyester.

A polyester film is preferable from the viewpoint of surface smoothness.

The metal or alloy has a thermal conductivity of 100 kcal/m
The temperature is below h・℃. Table 1 shows the thermal conductivity of various metals or alloys. In Table 1, each metal is indicated by the corresponding element symbol, and 5us18-8 means stainless steel.

Clothing-1 This metal or alloy is formed into a thin film by using a plastic film such as the above-mentioned polyester as a base film, and using a method such as vapor deposition or sputtering on the base film. For example, nickel and chromium can be formed into a thin film by a vaporization method using electron beam heating, and stainless steel and titanium can be formed into a thin film by a sputtering method using magnetron heating. Regarding the film thickness, it is desirable that the film thickness is between 10Oi and 1AOO.L.

At 100X or less, the film thickness becomes too thin, making it difficult to obtain a metallic luster (transparent), which is disadvantageous in terms of reflecting radiant heat. There is no problem with h''-, since the proportion of metal on the film increases,
It is directly affected by the thermal conductivity of the metal itself, and the thermal conductivity of the laminate film itself becomes worse. Furthermore, if the film thickness exceeds 1[]00A, there is a risk that cracks will occur in the metal layer itself and the gas barrier properties will deteriorate.

Next, the thermal conductivity of the film provided with the metal thin film layer having low thermal conductivity will be explained.

The film used for measurement was a 25μ polyester film.
This is a thick one with a thin layer of aluminum, nickel, chromium, titanium, or stainless steel.

The thin thickness was 400A for all metals.

The measurement method was an unsteady method in accordance with ASTM D 2326 or JIS R2618.

The measuring device used was Showa Denko's Shotherm QTM thermal conductivity.

Table 2 shows the measurement results of the thermal conductivity of the polyester film provided with each metal thin film layer.

Table 2 As shown in the above table, it can be seen that the films formed with thin film layers of Ni, Cr, SuS, and Ti have extremely low thermal conductivity compared to the A2 vapor-deposited film.

To manufacture an FFR thermal panel using this heat insulating film, first, another film that will become a sealant layer is laminated on the thin film layer surface of this heat insulating film.

Using the obtained laminated film, a lightweight, porous inorganic powder such as foamed bar light is hermetically packaged under vacuum. In addition to expanded perlite, activated carbon, calcium silicate, etc. can be used as the inorganic powder.

For example, as can be seen from the examples below, sxi.

torr is sufficient.

〔Example〕

A 25μ thick polyester film is used as the base film, on which a thin film layer of various metals or alloys is formed, and on top of this a 60μ thick linear low density polyethylene (UB manufactured by Tama Poly ■) is used as a sealant layer. -1) were laminated by a dry lamination method.

The metals or alloys used are as follows, and the thickness of each is 400A.

Invention 1: Nickel Invention 2: Chrome QMei 3: Stainless steel Invention 4: Titanium Prior art 5: Aluminum Using these films, the pressure was reduced to an appropriate degree of vacuum. The foamed perlite, which had been previously heat-dried at 15[]'C in an atmosphere, was sealed and packaged. The thermal conductivity of the obtained insulation panel is shown in Table 3 below.

As shown in the table above, when conventional A2 vapor-deposited products are vacuum packed,
To obtain a thermal conductivity of 0.01 kcal/mh℃,
However, a vacuum level of 10 torr was required.

When using the heat insulating film of the present invention, 5×1°tor
Thermal conductivity as a heat insulating material is 0.01 kca at a vacuum degree of r.
l/mh'C or less could be obtained.

The measurement was carried out using the steady method, and the measuring device was a Showa Denko Shot.
herm RTM thermal conductivity was used.

〔Effect of the invention〕

As mentioned above, a heat insulating material using the heat insulating film of the present invention is:
There is no need to create a high vacuum, which is technically difficult, as in the past.
Low thermal conductivity can be obtained, which is very advantageous for producing insulation materials.

Claims (1)

[Scope of Claims] 1) A heat insulating film made of a plastic film provided with a thin layer of metal or alloy having a thermal conductivity of 100 kcal/mh·°C or less. 2) The heat insulating film according to claim 1, wherein the thin film layer of metal or alloy has a thickness of 100 to 1000 angstroms. 3) With a plastic film provided with a thin layer of metal or alloy with a thermal conductivity of 100 kcal/mh・℃ or less,
A heat insulating panel characterized by a lightweight, porous inorganic powder such as expanded perlite that is sealed and packaged under vacuum. 4) The heat insulating panel according to claim 3, wherein the thin film layer of metal or alloy has a thickness of 100 to 1000 angstroms.