JPS63113286A - Vacuum heat-insulating panel - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a vacuum insulation panel that is easy to manufacture, is lightweight, and has good compression resistance and shape retention.

(Prior Art and its Problems) Conventionally, inorganic materials such as glass fiber and perlite, and organic materials such as foamed polyurethane and foamed polystyrene have been known as materials having a heat insulating effect.

Rigid polyurethane foam is generally used as a low-temperature insulation material, and it alone has a value of 0.015Kcal/+, h,
Although a thermal conductivity of C has been achieved, it is not easy to further improve the insulation performance.Also, double-walled materials are being used as cold insulation materials for cryogenic temperatures such as liquefied nitrogen containers and freezers. Vacuum insulation is generally used by filling the gap between containers with powder such as perlite or fibrous substances such as glass wool, silica alumina wool, and silica wool, and evacuating to a high vacuum of 0.01 Torr or less. It requires a thick and strong container that can withstand vacuum, which increases the weight.It also has disadvantages such as requiring a large volume of space for insulation.

As a countermeasure, we use plastic film laminated with metal foil such as aluminum or stainless steel.
A lightweight flat insulation panel is made by vacuum packaging powders such as perlite and silica powder and insulation materials such as glass wool using an exterior material made of a plastic film with a high barrier property against gas permeation with a thin film layer of the metal mentioned above. , which are then put together to make boxes and used for insulation purposes in freezers, etc.

However, although the use of an exterior material made of plastic film has the advantage of being lightweight, when powders and fibers are vacuum packaged by heat sealing in a vacuum, the powders and fibers may fly off or adhere to the heat seal area. In order to avoid heat-sealing failures, it took time and effort to fill powder, etc. into a breathable inner bag made of paper or cloth, then put it into an outer bag made of plastic film, and then vacuum package it.

In addition, since the powder or fiber heat insulating material 2 is compressed by vacuum pressure, the bulk density decreases, resulting in a tightly packed state.
As shown in the figure, wrinkles 3 are formed on the surface of the exterior material 1 of the vacuum insulation panel, which makes it difficult to assemble the panels and makes it difficult to install it in the insulation space inside the refrigerator.

Furthermore, it is difficult to produce panels with uniform thickness and fixed dimensions using fluid materials such as powder.

[Purpose of the invention]

In light of the above-mentioned current situation, the present invention provides vacuum packaging that can withstand compressive stress caused by vacuum, has a smooth surface, can retain its shape as determined in dimensions such as thickness, does not require an inner bag, and uses an exterior material made of plastic film. The purpose of the present invention is to provide a lightweight vacuum insulation panel that is easy to carry out, and to provide a insulation panel with a curved surface that matches the shape of a low-temperature container or the like.

[Summary of the invention]

The present invention uses silica tiles made from silica fibers that are porous and can withstand vacuum compressive stress as a heat insulating material, and the tiles are formed into square plate-shaped or disc-shaped rings with fixed dimensions to provide barrier properties against gas permeation. 0.01 in an exterior material consisting of a plastic laminated film bag with a high
This is a vacuum insulation panel obtained by heat sealing and vacuum packaging under a pressure of Torr or less.

Specifically, the specific gravity obtained by sintering silica fiber is 0.
．． 1 to 0.5, a silica tile molded body with a porosity of 80% or more, or a composite material molded body containing the same, with the inside of the pores of the insulation material kept in a vacuum, and vacuum packaged with an exterior material. It is an insulated panel.

An example of the method for manufacturing the silica tile used in the present invention will be described below.

When boric anhydride and alkali are added to silica (quartz) to lower the melting point and melted, and blown with air, it becomes 1 to 3 μ-
fibers are produced. This fiber is treated with acid to elute boric acid and alkali.

The voids after elution are eliminated by burning the fiber. It is preferable that the silica fiber contains 99.7% or more of silicon dioxide from the viewpoint of heat insulation. It is made by mixing colloidal silica with silica fiber and sintering it at 1316°C for 4 hours. In the case of tiles with a specific gravity of 0.14 manufactured by this method, the porosity is 90% or more.

Increasing the porosity and decreasing the specific gravity will reduce the strength of the tile and increase heat transfer by radiation, while decreasing the porosity and increasing the specific gravity will increase solid heat conduction.
It is desirable to use tiles of 0.5 in the present invention.

Furthermore, a composite molded body containing silica tiles is one in which an outer body having a space in the center is created using the aforementioned silica tiles, and the space of the outer body is filled with a powder heat insulating material such as silica powder or perlite powder. To make a heat insulating panel, it can be vacuum packaged in the same way as the silica tile described above.

[Effect]

Using silica tiles eliminates the need to use inner bags during vacuum packaging and creates panels with consistent dimensions that do not compress the insulation or wrinkle the surface of the insulation panel due to vacuum stress.

〔Example〕

A vacuum insulation panel produced by the method of the present invention will be described below with reference to the drawings, but this is merely an example and does not limit the present invention.

<Example 1> FIG. 1 shows an example of a vacuum insulation panel obtained by vacuum packaging silica tiles with an exterior material made of plastic film. 11 is an exterior material consisting of 3N: surface protection N/gas barrier layer/heat sealing layer, and the surface protection layer is
Polyethylene terephthalate film (thickness 12μ+i) with stainless steel sputtered on one side.
The gas barrier layer is a vinylidene chloride-vinyl chloride copolymer film (Saran HB manufactured by Dow Chemical Co., Ltd., [SA2
5 μm) + heat seal layer is polypropylene (thickness 6
Each layer was laminated using a dry lamination method using urethane-based adhesive side. This exterior material 11 has a flat plate shape (20ea x 20cm x 1ell
) A bag 12 is made according to the dimensions of the silica tile 15 made by molding the silica tile 15, and a dried silica tile 15 with a specific gravity of 0.14 and a porosity of 95% is placed in the bag 12. OL T
Heat sealing was performed under a pressure of orr or less and vacuum packaging was performed to obtain a heat insulating panel.

This panel has a smooth surface and a uniform thickness (10±0.51
Thermal conductivity when using silica powder with fi) is 0.005
It is better than Kcal/m,h,'C (10±2■■), and the thermal conductivity is about 0.004Kcal/m,h,'C, which is comparable to that when using silica powder.

<Example 2> Silica tiles 15 formed into a fan-shaped cross section as shown in Fig. 2 are combined and glued together as shown in Fig. 3 to form a cylindrical shape, which is then used as an exterior material (not shown) made of plastic film.
Vacuum packaging can be used to create insulation panels for tubular containers. The film used had the same three-layer structure as in Example 1,
Instead of sputtering stainless steel for the surface protection layer and gas barrier layer, aluminum was deposited to a thickness of about 400 λ.

The thermal conductivity of the above insulation panel is 0.005 Kcal/m
,h.

It was ℃.

<Example 3> A member 14 made of the same silica tile as in Example 1 and having a recess I7 surrounded by a peripheral wall 16 on one side as shown in FIG.
A composite material molded body consisting of a plate-like member 18 that covers the recess 17 and in which the recess 17 is filled with perlite powder 19 having a particle size of 20 to 40 μ is placed in a bag made of the exterior material used in Example 2, A vacuum insulation panel was obtained by heat sealing under a pressure of 0.01 Torr or less.

The thickness of the bottom wall and the thickness of the peripheral wall of the member (12) used for the composite molded body are both 7 fins, the height of the peripheral wall is 15 mm, and the center part of one plate-like member is 7 fins. The periphery of the crane was 5 cranes thick. And the outer circumference size is 20x20m@
It was formed into a square.

The thermal conductivity of this insulation panel is 0.005 Kcal/a
+, h.

It was ℃.

〔Effect of the invention〕

To obtain a vacuum insulation panel that is smooth and has constant dimensions such as thickness without wrinkles on the surface of the insulation panel because silica tiles are used as the insulation material so that vacuum packaging does not take much time and can withstand the compressive stress caused by vacuum. was completed.

As a result, the panels can be easily assembled and installed in narrow spaces inside refrigerators.

In addition, vacuum insulation panels of various shapes can be obtained by forming the silica tiles not only into flat shapes but also into curved shapes and by combining them.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing one embodiment of the present invention of a heat insulating panel made of vacuum-packed silica tiles, and FIG. 2 is an explanatory view of another embodiment of a silica tile in the shape of a cylinder divided into three parts. Fig. 3 is an explanatory diagram of a heat insulating material made by combining the molded bodies of Fig. 2 into a cylinder, Part 4 is a sectional view of a heat insulating panel of another example, and Fig. 5 is a sectional view of a conventional heat insulating panel. It is. 11... Exterior material 12... Bag 15... Silica tile patent applicant Toppan Printing Co., Ltd. Representative Kazuo Suzuki Figure 1 Figure 4 Figure 5

Claims (2)

[Claims] (1) Specific gravity 0.1-0 obtained by sintering silica fiber
．． 5. Maintaining a vacuum inside the pores of a heat insulating material made of either a silica tile molded body with a porosity of 80% or more or a composite molded body using this as a matrix, and covering this with an exterior material, A vacuum insulation panel characterized by being vacuum packed. (2) The vacuum according to claim 1, wherein the exterior material is either a plastic film laminated with a metal foil having a high heat reflectance such as aluminum or stainless steel, or a plastic film provided with a thin film layer of the metal. insulation panel.