JPS62246690A - Heat insulator - 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 Field of Industrial Application The present invention relates to a heat insulator for use in refrigerators, freezers, frozen prefabricated products, and the like.

BACKGROUND OF THE INVENTION In recent years, attempts have been made to use heat insulating bodies with reduced internal pressure in order to improve the heat insulating performance of heat insulating boxes.

The core material of this insulator is powder made of perlite,
Honeycomb and foam are used. For example, referring to FIG. 4, 1 is a heat insulator, a hard urethane foam 2 having open cells is covered with a container 3 made of an airtight thin film, and the inside is depressurized to 0.001 mHy.
It's sealed.

Problems to be Solved by the Invention However, with the above configuration, it is difficult to uniformly reduce the pressure inside the hard urethane foam 2 in a short time, and it is necessary to exhaust the gas such as the blowing agent that swells inside the resin skeleton. It is possible that it cannot be done. For this reason, even if the initial thermal conductivity is excellent, the internal pressure of the insulator 1 will increase over time due to gases such as fluorocarbon gas and 002 that gradually diffuse from the resin skeleton, and the thermal conductivity will increase. be.

For example, 30 cm x 30 on x 2 cm
(A hard urethane foam with a volume of 1800 (! 11!) was dried at 120 to 140 degrees Celsius, which is close to the heat-resistant temperature, for about an hour, and the gas that swelled in the skeleton was collected and analyzed 3... It is known that about 20 to 40 m remains.It is expected that this will diffuse into the inside of the heat insulator 1 while experiencing diffusion resistance of the bubble membrane and resin skeleton.Also, according to experiments, it will take a long time to reach pressure equilibrium. Approximately 30 days at room temperature, 12
Even in an atmosphere of 0 to 140'C, 1 to 2 days of aging was required. It is thought that the swelling gas increases the internal pressure and deteriorates the thermal conductivity in the long term.

In order to prevent this, it will be necessary to maintain the heat insulator 1 at a temperature of at least 120 to 140°C and continue to evacuate it with a vacuum pump for one day or more. That is, by this operation, the gas remaining in the resin skeleton can be exhausted and the pressure can be reduced to a predetermined pressure. However, in production, this operation can only produce one exhaust system per day, and mass production is extremely difficult.

In view of the above-mentioned problems, the present invention aims to improve productivity by reducing the pressure to a predetermined pressure in a short time, maintain the insulation performance of the heat insulator over a long period of time, and ensure quality reliability. .

Means for Solving the Problems In order to solve the above problems, the present invention provides a plurality of rigid urethane foam plates made by mixing and foaming an organic polyisocyanate, a polyol, a catalyst 2 blowing agent, and a cell communication agent;
Between the plurality of hard urethane foam plates, a core material made of a material such as soft foam having a compressive strength of at least 1 to 9/C11 or less and having an air permeable spacer interposed therebetween is used. A core material made of a material such as a soft foam having a compressive strength of at least I Ky/cA or less and having an air permeable spacer interposed between a plurality of hard urethane foam plates having air bubbles is covered with a container made of a metal-plastic laminate film. Since the inside pressure is reduced, the inside of the heat insulator can be uniformly reduced to a predetermined pressure in a short time by exhausting air from the spacer.

To Embodiment 5 - Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 4 is a hard urethane foam plate obtained by cutting hard urethane foam into thin plates of 5 to 10 pieces, which was foamed and cured in a urethane high-pressure foaming machine using the raw materials and blended parts shown in the table below.

In the above table, the polyol is a polyether polyol having a hydroxyl value of 442 qKcH/p obtained by addition polymerizing propylene oxide using aromatic diamide as an initiator. The foam stabilizer was silicone surfactant F-318 manufactured by Shin-Etsu Chemical Co., Ltd., and the foaming agent was Freon R-11 manufactured by Showa Denko KK. The catalyst is dibutyltin dilaurate. The bubble communication agent is calcium stearate manufactured by NOF Corporation. Organic polyincyanate is a polyisocyanate with an amine equivalent of 150 obtained by reacting toluylene diisocyanate, trimethylpropane, and diethylene glycol. A hard urethane made by blending these raw materials in the indicated proportions and foaming with a urethane high-pressure foaming machine. / form 6
After cutting into thin plates of ~10 wL, it is heated at 140° C. for about 1 hour to evaporate adsorbed moisture and exhaust gas that swells in the resin skeleton. A soft foam 5 of 0.6 to 1111 is interposed between such hard urethane foam plates 4,
Container 6 made of metal-plastic laminate film
The soft 7 ohm 5 contracts to about 0.11 J& by reducing the pressure inside to o, otsnHy, and the heat insulating body 7 is obtained.

In this way, by cutting the hard urethane foam into thin plates, the gas that swells inside the resin skeleton can be efficiently exhausted even during drying, and by interposing the soft foam, it is possible to vacuum pack a heat insulator of the same thickness. It is possible to uniformly reduce the pressure to a predetermined pressure in a much shorter time than it would otherwise take.

In one embodiment of the present invention, two layers of hard urethane foam boards are used, but as shown in Figure 3, it is possible to use three or more layers stacked together, reducing the drying time and exhaust time. It can be further shortened.

As described above, by using a core material in which a spacer made of soft foam is interposed between hard urethane foam plates, it is possible to uniformly reduce the pressure inside the insulation to a predetermined pressure in a short time, and the pressure can be reduced over time. It is also possible to maintain insulation performance over a long period of time without generating gas.

[Brief explanation of drawings]

FIG. 1 is an external perspective view of a hard urethane foam according to an embodiment of the present invention, FIGS. 2 and 3 are sectional views of the same heat insulating body, and FIG. 4 is a sectional view of a conventional heat insulating body. 4...Hard urethane foam board, 5...
Soft foam, 6...container, 7...insulator. . Name of agent: Patent attorney Toshio Nakao and 1 other person - ~ Shiro Shiro 1
! Kasou So

Claims (1)

[Claims] Organic polyisocyanates, polyols, catalysts, foam stabilizers,
A compressive strength of at least 1 is interposed between a plurality of rigid urethane foam plates having an open cell structure formed by mixing a foaming agent and a cell communication agent, and the rigid urethane foam plates.
A metal-plastic laminate film that covers a core material made of a breathable spacer made of a flexible foam made of a material of Kg/cm^2 or less and the hard urethane foam board and the spacer, and can seal the inside under reduced pressure. A heat insulator consisting of a container.