JPS62147275A - Manufacture of 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 and freezers.

BACKGROUND OF THE INVENTION In recent years, attention has been paid to the use of heat insulating bodies with reduced internal pressure in order to improve the heat insulating performance of heat insulating boxes. FIG. 4 shows a conventional heat insulator. The configuration of the conventional example will be explained below with reference to FIG. 4.

In the figure, 1 is a heat insulator, 2 is a breathable inner bag, and 3 is a powder such as perlite filled in the inner bag 2. Reference numeral 4 denotes a bag-shaped container made of a metal-plastic laminate film or the like made of a laminated structure of an aluminum vapor-deposited polyester film and a polyethylene film, and an inner bag 2 filled with powder 3 is inserted into the container 4 to open the interior.
After the pressure is reduced to approximately mHy, the opening of the container 4 is sealed by heat fusion to form the heat insulator 1.

Problems to be Solved by the Invention However, in the conventional example, the thermal conductivity of the heat insulating body 1 is O,OO61al/rnh'C, and it has an excellent heat insulating performance that is 2 to 3 times that of polyurethane foam heat insulating material. As shown,
As a result of the powder 3 being densely packed by atmospheric compression, it has a density of 0.26 to 0.0, which is 10 times the density of polyurethane foam insulation.
30y/cr! It was extremely heavy. For this reason, there have been disadvantages such as making it difficult to transport products using the heat insulating body 1 and not being able to use it in small portable heat insulating boxes.

The present invention eliminates the drawbacks of the above-mentioned conventional examples, and aims to reduce the weight of the heat insulator without impairing its heat insulation performance.

Means to Solve the Problems In order to solve the above-mentioned problems, the present invention uses organic polyisocyanate, polyol, catalyst 9 blowing agent, and cell communication agent as raw materials, and after foaming and curing, a skin formed on the outer surface. The core material of the heat insulator is made of hard urethane foam with the remaining parts removed.

Effect: With the above configuration, the cell membrane is broken during the foaming process, and after the foaming and curing, the skin part of the cell where the resin film of the cell is thick and is difficult to break even with a cell communication agent is removed, and the open cell ratio is reduced to 10.
0% hard urethane foam as the core material, covered with a container made of metal-plastic laminate film,
In order to reduce the internal pressure, the internal pressure of the insulator can be uniformly reduced to a predetermined pressure, and since there are no closed cell parts, the initial insulating performance is maintained without any increase in internal pressure over a long period of time.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4.

In the figure, 5 is a hard urethane foam block which was foamed in an open tunnel jig e using a urethane high-pressure foaming machine using the raw materials and blended parts shown in Table 1, and then cured.

Table 1 In Table 1, the polyol is a polyether polyol having a hydroxyl value of 440 to KOH/y obtained by addition polymerizing propylene oxide using an aromatic diamine as an initiator. The foam stabilizer is silicone surfactant F- manufactured by Shin-Etsu Chemical ■.
317, the blowing agent is Freon R-11 manufactured by Showa Denko ■. The catalyst was dimethylethanolamine, and the bubble communication agent was calcium stearate manufactured by NOF ■. The organic polyin 7-anate is a polyin 7-anate having an amine equivalent of 150 obtained by reacting toluylene diinocyanate with trimethylpropane and diethylene glycol.

These raw materials were combined and foamed to obtain a hard urethane foam block 6.

Thereafter, a hard urethane foam board 8 was cut into a predetermined size except for the high-density skin part 7 formed on the outer surface of the hard urethane foam block 6, and a high-density skin part 7 formed on the outer surface of the hard urethane foam block 6 was cut as a comparative example. A hard urethane foam board 9 with a skin was produced, with the skin portion 7 remaining. The respective densities and open cell ratios are shown in Table 2. Then, each was heated at 120'C for about 2 hours to evaporate the adsorbed water, etc.
It is covered with a bag-shaped container 4 made of a metal-plastic laminate film with a laminate structure of an aluminum-deposited polyester film and a polyethylene film, and the inside is covered with a 0.
05 Reduce the pressure with ff1llH, d, seal and insulate 1o
I got it. The initial thermal conductivity of the obtained heat insulator 1o immediately after sealing and the thermal conductivity after 30 days are also shown in the table. Thermal conductivity was measured using K-Mattc manufactured by Shinku Riko ■ at an average temperature of 24°C.

Table 2 As is clear from Table 2, in the case of the skinned hard urethane foam plate 9 having the skin portion 7, since the skin portion 7 is not completely open-celled, it does not have excellent thermal conductivity immediately after vacuum sealing. It has been found that even if there is, gases such as chlorofluorocarbon gas, carbon dioxide gas, and air contained in the closed cells diffuse over time, increasing the internal pressure of the heat insulator 1o and deteriorating the thermal conductivity. On the other hand, it was found that the hard urethane foam board 8 excluding the skin portion γ had a uniform open cell structure and exhibited excellent thermal conductivity both initially and after aging. Regarding the formation of open cells in the skin part 7, since the resin film of the cells is thick, the foam-breaking agent makes the film thickness uneven and does not break the cells.
It is thought that closed cells are left behind, but the details of this mechanism have not yet been elucidated. As described above, by removing the skin portion 7, the heat insulating performance of the heat insulator 10 does not deteriorate over a long period of time, contributing to quality assurance.

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

Organic polyisocyanates, polyols, catalysts.

Foam Stabilizer 1 The foaming agent and the cell communication agent are used as raw materials, and the hard urethane 7 ohm obtained by mixing and foaming, and then removing the skin portion formed on the outer surface, has closed cells with an open cell ratio of 100%. Since it has a cell structure with no gas, it is covered with a container made of metal-plastic laminate film, and when the inside is depressurized, there is no closed cell that contains gas, so even if the insulation is left for a long time, no gas will be released from the closed cell. There is no gas diffusion and no pressure rise occurs. Therefore, the heat insulating performance of the heat insulator does not deteriorate, and quality stability is ensured.

[Brief explanation of drawings]

Fig. 1 is an external perspective view of a hard urethane foam block according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of the hard urethane foam block showing the cutout position of the hard urethane foam board, and Fig. 3 is a cross-section of the same heat insulator. FIG. 4 is a sectional view of a heat insulator in a comparative example, and FIG. 6 is a sectional view of a heat insulator in a conventional example. 4...Container, 7...Skin part, 8...
...Hard urethane foam, 10...Insulator.

Claims (1)

[Claims] Organic polyisocyanates, polyols, catalysts, foam stabilizers,
A foaming agent and a cell communication agent are used as raw materials, and after mixing, foaming and curing, the skin portion formed on the outer surface is removed, and a rigid urethane foam with an open cell structure is obtained as a core material, and this is used as a metal-plastic material. A method for producing a heat insulator that is covered with a container made of laminate film and sealed by reducing the pressure inside.