JPH0810112B2 - Insulation - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat insulator used for a refrigerator, a frozen prefab, or the like.

2. Description of the Related Art In recent years, attention has been paid to the use of a heat insulating body whose inside pressure is reduced in order to improve the heat insulating performance of the heat insulating box. Figure 6 shows
1 shows a conventional insulation. The configuration of the conventional example will be described below with reference to FIG.

In the figure, reference numeral 1 is a heat insulator, in which a breathable inner bag 4 filled with perlite powder 3 is inserted into a metal-plastic slaminate film container made of an aluminum vapor-deposited polyester film and a polyethylene film, and the inside is 0.1 mmHg. It is made by decompressing to a certain degree and sealing it. The density of the heat insulator 1 is 0.25 to 0.30 g / cm ³ , and the thermal conductivity is 0.0
It was 07 kcal / mh ° C.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention Since such a heat insulator 1 uses perlite powder 3 which is an inorganic material as a core material, glass wool, hard urethane foam or phenol foam generally industrially used as a heat insulating material. The density is 5 to 10 times that of
There is a problem in workability in using the heat insulator 1 for various heat insulating applications.

In view of the above problems, the present invention is industrially easy to handle
The purpose is to have excellent heat insulation performance at a reduced pressure of about 0.1 to 0.01 mmHg and to achieve weight reduction.

Means for Solving the Problems In order to solve the above problems, the present invention provides a heat insulator in which a rigid urethane foam plate having an open cell structure is covered with a container made of a metal-plastic slaminate film to reduce the pressure inside and to close the inside. In the above, the rigid urethane foam plate is cut so as to have a cell skeleton extending in the foaming direction when the rigid urethane foam is formed, and is overlapped in a laterally long direction substantially perpendicular to the heat transfer direction.

Action With the above configuration, the rigid urethane foam plate is cut so as to have a cell skeleton extending in the foaming direction when the rigid urethane foam is formed, and the cell skeleton is substantially perpendicular to the heat transfer direction and overlaps in a horizontal direction. The orientation is laterally long with respect to the heat direction, the heat transfer distance becomes the longest, and as a result, the heat transfer resistance increases.

Example Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 5.

In the figure, reference numeral 5 is a rigid urethane foam having an open-cell structure which is foamed and cured by a urethane foaming machine using the raw materials and the number of orientation parts shown in the table. Foaming is 25 cm x 25 cm x 25 cm
After aging at room temperature, the plate was cut into a plate shape with a thickness of 2 cm in parallel with the foaming direction to obtain 12 hard urethane foam plates 6 after aging at room temperature. As a comparative example, a hard urethane foam plate 7 cut perpendicular to the foaming direction was also obtained.

In the table, the polyol is a polyether polyol having a hydroxyl value of 442 mgKOH / g obtained by addition-polymerizing propylene oxide with an aromatic diamine as an initiator. The foaming agent is a silicone surfactant F-33 manufactured by Shin-Etsu Chemical Co., Ltd.
5. The blowing agent is Freon R-11 manufactured by Showa Denko KK.
The catalyst is dimethylethanolamine, and the air bubble communication agent is
This is calcium stearate manufactured by Nippon Oil & Fats Co., Ltd. The organic polyisocyanate is a prepolymer polyisocyanate with an amine equivalent weight of 150. The density of the rigid urethane foam plates 6 and 7 foamed from these raw materials was 40 to 45 kg / m ³ , and the open cell ratio was 100%.

Then, the mixture is heated at 120 ° C. for about 2 hours to evaporate the adsorbed moisture, and is covered with a container 2 made of a metal-plastic s laminated film having a laminated structure of an aluminum vapor-deposited polyester film and a polyethylene film.
The pressure is reduced to mmHg and sealed to obtain a heat insulator 8. The obtained heat insulator 8 has a thermal conductivity of 0.0060 when the hard urethane foam plate 6 formed by cutting in parallel with the foaming direction is used as the core material.
~ 0.0066kcal / mh ° C, and the one using the hard urethane foam plate 7 cut perpendicular to the foaming direction as the core material is 0.00
It was 85 to 0.0098 kcal / mh ° C.

Thus, the hard urethane foam plate 6 obtained by cutting the rigid urethane foam 5 having an open-cell structure in parallel to the foaming direction uses the hard urethane foam plate 7 obtained by cutting it vertically as the core material. From this, it was found that the heat insulation performance was about 1.5 times better. This is due to the shape of the cell skeleton. That is, since the cell skeleton of the rigid urethane foam 5 extends and is oriented along the foaming direction (arrow A in the figure), in the case of the rigid urethane foam plate 6, the cell structure is different from the heat transfer direction (arrow B in the figure). Has a horizontally long cell skeleton, and conversely, the hard urethane foam plate 7 has a cell skeleton that is vertically long with respect to the heat transfer direction. Among the heat transfer, the conductive heat transfer conducted through the bubble skeleton has a longer length of the conductive heat transfer flowing through the bubble skeleton in the rigid urethane foam 6 in which the bubble skeletons overlap in the lateral direction, and as a result, the heat transfer resistance is increased. It is large and the heat insulation performance is good. Therefore, it is possible to provide an excellent heat insulating material which is lightweight and industrially easy to handle at a reduced pressure of 0.1 to 0.01 mmHg.

Effects of the Invention As is apparent from the above description, the present invention provides the following effects.

The rigid urethane foam plate having an open-cell structure obtained by cutting in parallel with the foaming direction has a cell skeleton that is long in the heat transfer direction. As a result, the heat transfer length of solid heat conduction through the bubble skeleton is increased, the heat transfer resistance is increased, and the solid heat conductivity is small. And a heat insulator made by covering this hard urethane foam plate with a container made of metal-plastic slaminate film and decompressing the inside to seal it as a heat insulating material that retains excellent heat insulating performance and is lightweight and has good workability. It can be used.

[Brief description of drawings]

FIG. 1 is an external perspective view of a rigid urethane foam according to an embodiment of the present invention when foaming is completed, and FIG. 2 is an external perspective view of a rigid urethane foam plate obtained by cutting the rigid urethane foam parallel to the foaming direction. FIG. 4 is a cross-sectional view of a heat insulating body having the rigid urethane foam plate as a core material, FIG. 4 is an external perspective view of the rigid urethane foam plate obtained by cutting the rigid urethane foam perpendicularly to the foaming direction, and FIG. 5 is a rigid urethane foam. FIG. 6 is a cross-sectional view of a heat insulator having a plate as a core material, and FIG. 6 is a cross-sectional view of a conventional heat insulator. 2 ... Container, 6 ... Hard urethane foam plate, 8 ... Heat insulator.

Claims (1)

[Claims] 1. A heat insulator in which a rigid urethane foam plate having an open-cell structure is covered with a container made of a metal-plastic slaminate film to reduce the pressure inside and to be sealed, wherein the rigid urethane foam plate is foamed when the rigid urethane foam is formed. Cut to have a bubble skeleton extending in the direction,
A heat insulator characterized in that the skeletons of the cells are substantially perpendicular to the heat transfer direction and are horizontally long.