JPS6361590B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a heat insulator for the body and door of a refrigerator.

Generally, the main body and door of a refrigerator are made by injecting raw material for foamed resin insulation material (hereinafter referred to as foaming raw material) into a cavity of a hollow casing made of a metal plate or a synthetic resin plate and causing it to foam.

However, in order to enhance the heat insulation effect, the thickness of the foamed resin layer must be increased, which increases the external size compared to the internal capacity of the refrigerator, resulting in design constraints and installation space problems.

It is known that if a vacuum layer is formed within the foamed resin material, a sufficient heat insulating effect can be obtained even if the wall thickness is thin, and a refrigerator with a large capacity compared to its external size can be manufactured. However, a technique for foaming a foaming raw material in a cavity and forming a hollow vacuum layer within the foamed resin material thus formed has not yet been established.

As one step closer to a heat insulator having a hollow vacuum layer, as shown in FIG. 4, a thin bag 5 is filled with inorganic foam powder 52, and a heat insulating member 53 kept in a vacuum state is suspended in the cavity. Insulating foam material 6 supported by and foamed within the cavity
There is a heat insulating body surrounding the heat insulating member 53 (Utility Model Application No. 119187/1987).

However, the above-mentioned heat insulator requires time and effort to fill the bag with foam powder, and heat transfer occurs due to contact between the inner surface of the bag and the foam powder, and contact between foam powders, so it is difficult to ideally form a hollow vacuum layer within the wall. There was a gap between us.

〔the purpose〕

An object of the present invention is to provide a heat insulating body that forms a vacuum layer without a filler in a foamed resin material and has an excellent heat insulating effect even if the wall thickness is thin.

〔composition〕

The raw material for the foamed heat insulating material is foamed on the outside of the bag 5 which is placed in the cavity and expanded by filling with compressed fluid, and the outside of the bag is covered with a foamed resin material 6, and the foamed resin material 6 is applied to the surface of the bag 5. The foamed resin material is solidified in the foamed resin material, and then the fluid inside the bag 5 is discharged to maintain the bag 5 in a vacuum state, thereby forming a hollow vacuum layer within the foamed resin material.

[Action and effect]

When foaming the foaming raw material, the bag is filled with fluid, so the bag is not crushed by the foaming pressure.

In addition, after foaming is completed, the foam material adheres to the bag surface and solidifies, supporting the bag's shape, so the fluid inside the bag can be drained and the inside of the bag can be created as a vacuum chamber, and even if it is thin, it has a heat insulation effect. An extremely excellent heat insulating body is formed, and the weight of the heat insulating body can be reduced.

The present invention will be specifically described below based on embodiments shown in the drawings.

Although FIG. 1 shows a refrigerator door 1 manufactured by the method of the present invention, the present invention is not limited thereto, and can be applied to the manufacture of a refrigerator body 12, a heat insulating body such as a heat insulating panel for construction, etc.

The refrigerator door 1 has a foamed resin material 6 wrapped in a hollow casing formed by a front plate 2, a back plate 3, and an outer peripheral end plate 4, and inside the foamed resin material 6 is a flat plate in the direction of the plate surface of the door. A hollow vacuum layer 9 slightly smaller than the surface is formed.

A packing 11 is attached to the outer periphery of the back side of the door,
A shelf portion 31 is resin-molded on the back plate 3.

Next, the manufacturing method of the above door will be explained.

First, the back plate 3 is fitted into the lower mold 81 of the split mold 8, and the foaming raw material 90 is injected from above the back plate 3. The foaming raw material in the example is a mixture of two liquids: isocyanate and polyol.

Next, the end plate 4 is assembled around the outer periphery of the top plate 2.
A hollow flat bag 5 is suspended and supported on the inner surface of the bag 5 by a stay 7, and a member 10 with a stay 7 attached to the lower surface of the bag 5 is placed over the back plate 3, and the lower stay 7 is attached to the inner surface of the back plate 3. , and the back plate 3 and the member 10
A cavity is formed between the two.

The bag 5 is made of aluminum foil or a thin stainless steel plate with a thickness of 30 to 50 μm, and is slightly smaller in area than the top plate 2, and the space thickness 91 is about 2 cm.

The outer peripheral surface of the bag 5 is roughened or coated with a resin coating layer that has excellent adhesion to the foaming raw material.

A fluid inflow pipe 51 is protruded from one end of the bag 5, and when the member 10 including the bag 5 is placed on the back plate 3 as described above, the inflow pipe 51 is inserted into the mold 8 from the cutout 81a of the lower mold 81. Connect to the hose H for supplying and discharging pressurized air.

The stay 7 has circular abutment plates 72, 72 protruding from both ends of a short shaft 71, and is adhesively fixed to the inner surface of the top plate 2 and the bag 5.

The height of the stay 7 is approximately 1.5 cm.

Next, pressurized air is supplied into the bag 5 from the hose H. The pressure of the pressurized air may be such that the bag 5 is not crushed by the pressure of foaming the foaming raw material 90 in the cavity.

During the above operation, the foaming raw material 90 continues to foam within the cavity, and the foam material 6 covers the outer periphery of the bag 5.
Since the outer surface of the bag 5 is roughened or coated with a resin coating layer, the bonding force between the foamed resin material and the bag is increased, and the foamed resin material and the bag are firmly integrated.

Foaming is completed in 4 to 5 minutes after injection of the foaming raw material,
Foams approximately 30 times more.

Next, before or after removing the completed door from the mold 8, the air inside the bag 5 is removed to create a vacuum state, and the tube 51
The remaining length is cut off and the flow path to the bag 5 is closed.

As mentioned above, the heat insulating material 6 and the bag 5 are firmly connected together, and the heat insulating material 6 is also adhesively bonded to the top plate 2 and the back plate 3, so even if the air in the bag 5 is evacuated, the bag will remain intact. 5 will never be destroyed.

Through the above steps, a refrigerator door having an extremely excellent heat insulating effect and having a vacuum hollow layer in the heat insulating resin layer is completed.

In carrying out the present invention, the fluid to be filled in the bag 5 is not limited to air, and other gases or liquids may be used, and the present invention is not limited to the above configuration, and the fluid filled in the bag 5 is not limited to air. Of course, various modifications are possible within the technical scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a refrigerator door, FIGS. 2 and 3 are explanatory views of the process order, and FIG. 4 is a sectional view of a conventional example. 5...Bug, 6...Foamed resin material, 9...Hollow.

Claims (1)

[Claims] 1. A raw material for a foamed heat insulating material is foamed on the outside of a bag 5 which is disposed in a cavity and expanded by being filled with compressed fluid, and the outside of the bag is covered with a foamed resin material 6, and the foamed resin is A heat insulator characterized by solidifying the material 6 on the surface of the inflatable bag 5, then draining the fluid inside the bag 5 to maintain the bag 5 in a vacuum state, and forming a hollow vacuum layer 9 within the foamed resin material. manufacturing method. 2. The method for manufacturing a heat insulator according to claim 1, wherein the fluid is air. 3. The bag is made of a thin metal plate such as aluminum foil or stainless steel plate.
A method for producing a heat insulating body according to item 1 or 2. 4. The method for manufacturing a heat insulating body according to any one of claims 1 to 3, wherein the heat insulating body is a door of a refrigerator. 5. The method for manufacturing a heat insulator according to any one of claims 1 to 3, wherein the heat insulator is a main body of a refrigerator.