JPH0446208B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat insulating wall used for refrigerator doors, etc., in which a foamed heat insulating material is foamed and filled between a pair of exterior panels, and a method for manufacturing the same.

Configuration of the conventional example and its problems The configuration of the conventional example will be explained with reference to FIGS. 1 to 5.

In the figure, reference numeral 1 indicates insulation of a refrigerator door, which is formed from a door panel 2 serving as an exterior plate, a foamed insulation material 5 made of hard urethane foam that is injected and foamed into a space formed by an inner door 3 and a sash 4 surrounding the outer periphery of the door panel 2. It's a wall. Further, a gasket 6 is inserted and fixed to the outer periphery of the inner door 3 before raw materials such as hard urethane foam are injected.

Reference numeral 7 denotes an injection port provided at the bottom of the sac 4 (lower side in Figure 1).The injection port is placed upward as shown in Figure 2, and the hard urethane foam insulation material raw material is supplied from the foaming machine head 8. Injected. At this time, the hard urethane foam insulation material raw material from the lower part becomes a foam fluid and starts foaming while repeating foaming and polymerization reactions. (Situation shown in Figure 3) Furthermore, as the foaming rate and polymerization reaction progress over time, the rigid urethane foam fluid becomes highly viscous. As a result, the flow resistance between the door panel 2 and the exterior plate of the inner door 3 becomes large, and the tip 9 of the foam fluid causes turbulent flow, causing the gas pool 10 to flow toward the inner surface (urethane foam side) of the exterior plate of the door panel 2 and the inner door 3. (Situation shown in Figure 4).

Since this gas reservoir 10 replaces the fluorocarbon gas contained in the hard urethane foam, the pressure decreases due to the liquefaction of the gas at low temperatures, which not only deforms the exterior panels of the door panel 2 and inner door 3 but also significantly reduces the insulation performance. This was becoming a very big problem. Conventionally, as a solution to this problem, the door panel 2 and inner door 3 near the final filling part of the foam insulation material such as hard urethane foam
This was done by attaching a sheet with a ventilation layer, such as soft urethane foam, to the inner surface of the exterior plate using an adhesive, or by providing gas vent holes at appropriate locations. However, if this method is used,
This method not only requires a large number of parts and expensive materials, but also has the drawbacks of being difficult to work with.

OBJECTS OF THE INVENTION The present invention aims to improve the above-mentioned drawbacks, and aims to eliminate gas pockets and reliably prevent deformation at low temperatures and deterioration of heat insulation performance.

Composition of the Invention In order to achieve this object, the present invention interposes a lightweight powder between the injection of the foamed insulation material raw material and the completion of the filling, and traps this lightweight powder in the gas reservoir during filling and foaming. By doing so, the purpose is achieved.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 6 to 8.
The description will be made with reference to the drawings, but structures that are the same as those of the prior art will be given the same numbers and detailed descriptions thereof will be omitted.

11 is a lightweight powder such as pulverized material of expanded styrene beads or hard urethane foam. This lightweight powder 11 is formed by injecting a hard urethane foam insulation material raw material from a foaming machine head 8 through an injection port 7, and then scattering an appropriate amount onto the foam fluid through the same injection port 7.

Next, the foam filling process in such a state is shown in Figure 6~
This will be explained with reference to FIG. That is, the hard urethane foam insulation material raw material is injected into the foaming machine head 8 through the injection port 7, and then the lightweight powder 11 is spread (as shown in FIG. 6). Then, the hard urethane foam insulation material raw material becomes a foam fluid, and filling starts while proceeding with foaming and polymerization reactions. At this time, the lightweight powder 12 sprinkled on the foam fluid is lighter than the density of the foam fluid, so it does not interfere with the foaming/polymerization reaction and foaming. Furthermore, as the foaming and polymerization reactions progress over time, the rigid urethane foam fluid becomes highly viscous. As a result, the flow resistance between the door panel 2 and the exterior plate of the inner door 3 increases, and the flow progresses while causing turbulence (the state shown in FIG. 7). However, the tip 9 of the foam fluid and the door panel 2
The lightweight powder 11 that has been sprinkled on the foam fluid is a fine powder with a high degree of freedom, so it naturally falls into the gas pocket 10 formed between the outer panel of the inner door 3 and the outside plate of the inner door 3. Then, it is filled. The foaming/polymerization reaction further progresses, and filling is completed (state shown in FIG. 8).

In this way, after injecting the hard urethane foam insulation material raw material, by interposing the lightweight powder 11, the lightweight powder 11 is placed in the gas pockets formed on the urethane side of the exterior panels of the door panel 2 and the inner door 3.
1 is filled, it is possible to prevent the formation of a cavity in the gas pocket as in the conventional case. Therefore, unlike the conventional example, the fluorocarbon gas liquefies during cooling, the pressure inside the cavity decreases, and the door panel and the exterior plate of the inner door are not deformed, and the heat insulation performance can be maintained. It is also easy to work with, can handle gas pockets that occur in uncertain locations, and can provide a heat insulating wall with stable quality.

Effects of the Invention As is clear from the above explanation, since the gas reservoir of the heat insulating wall of the present invention is filled with lightweight powder, even if the fluorocarbon gas in the gas reservoir becomes liquefied during cooling and a vacuum state is created, the exterior This prevents deterioration in heat insulation performance without deforming the plate.

In addition, after injecting the foam insulation material raw material, simply scattering the lightweight powder from the same injection port will deal with the gas pockets that form in the uncertain areas, and the lightweight powder will be reliably filled into the gas pockets, making it very easy to use. You can get insulated walls of stable quality. Furthermore, the hard urethane foam pulverized material can be used as a lightweight powder to recycle the hard urethane foam that is no longer needed, resulting in effective use of resources.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a conventional heat insulating wall as a refrigerator door, Fig. 2 is a longitudinal sectional view of a conventional heat insulating wall before filling with hard urethane foam, and Figs.
Fig. 5 is a longitudinal cross-sectional process diagram of a heat insulating wall showing the conventional hard urethane foam filling process; Fig. 6 is a longitudinal cross-sectional view of the heat insulating wall showing the feeding state of lightweight powder according to an embodiment of the present invention; A vertical cross-sectional view of a heat insulating wall showing how lightweight powder naturally falls when a gas pocket is generated.
FIG. 8 is a longitudinal sectional view of the insulation wall after filling is completed. 2, 3...Exterior board, 5...Foam insulation material, 7...
Inlet, 10...Gas reservoir, 11...Lightweight powder.

Claims (1)

[Claims] 1. A thermal insulation consisting of a pair of exterior plates held at a predetermined interval, a foam insulation plate filled between the exterior plates, and a lightweight powder located in a gas pocket in the foam insulation material. wall. 2. A method for manufacturing a heat insulating wall, in which a foamed insulation material is injected between a pair of exterior plates held at a predetermined interval, and is filled between the pair of exterior plates through a foaming/polymerization reaction. A method for manufacturing a heat insulating wall by filling a lightweight powder between the time of injection of raw material and the end of filling.