JPH0272294A - Heat insulating structure - Google Patents

Abstract

PURPOSE:To shorten the exhaust time so as to enable mass production to be attained by sheathing a foaming material of open cell structure with a vessel of metal and plastic laminated film and reducing a pressure in the inside to close it. CONSTITUTION:A foaming material of open cell structure, obtained by additionally compounding 10 to 30% polyether polyore with an aromatic amine compound serving as the initiator for benzylic ether type phenol resin further by mixing a catalyst, bubble arranging agent, foaming agent and a foam communication agent, is externally coated with a vessel 5 formed by a metal and a plastic laminated film, and reducing a pressure in the inside of the vessel to close it, a heat insulating structure 6 is obtained. Thus because a core member is formed by fine foam framework, it is coated with the vessel 5 formed by the metal-plastic laminated film, when a pressure in the inside is reduced, excellent heat insulating performance is obtained even by a pressure of about 0.1 to 0.01mmHg easy to handle industrially, and mass production efficiency is substantially improved by shortening the exhaust time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat insulator used in refrigerators, frozen prefabricated products, and the like.

BACKGROUND OF THE INVENTION FIG. 3 shows a conventional heat insulator. The configuration of the conventional example will be explained below with reference to FIG.

In recent years, attention has been paid to the use of a heat insulating body with a reduced internal pressure in order to improve the heat insulation performance of the heat insulating box. As the core material of this heat insulating body, powder such as perlite, honeycomb, foam, etc. are used. For example, JP-A-57-1338
As shown in No. 7.0, a proposal has been made to use a hard urethane foam having open cells as a core material. This Japanese Patent Application Laid-Open No. 57-133870 is explained with reference to FIG. 3. In the figure, 1 is a heat insulating structure, in which a hard urethane foam 2 having open cells is covered with a container 3 made of an airtight thin film, and the interior thereof is The pressure was reduced to 0.001 Hqi and the container was sealed. The hard urethane foam 2 has a cell skeleton diameter of 300 to 10
It is characterized by the fact that a commercially available general material with a diameter of about 0.00 μm is vacuum degassed under high temperature and high humidity to burst the bubbles and obtain open cells.

Problems to be Solved by the Invention In such a heat insulating structure 1, since the bubble skeleton diameter of the rigid urethane foam 2 is 300 to 1000 μm, the thermal conductivity of the gas will decrease unless the pressure is 0.001 rmHg or less. It is not small enough, and excellent heat insulation properties cannot be obtained. Basically, the thermal conductivity of a gas decreases rapidly when the wall pressure II of the gas layer (in this configuration, the bubble skeleton diameter) becomes shorter than the mean free path of the gas, but as the wall distance increases, Lower pressures are required to obtain the same gas thermal conductivity. As a general formula, gas thermal conductivity (KL
i) is expressed by the following equation (1).

Kq=A-p-V-CrCLl-d/(Lf+d))-
=-(1) formula % formula %) Lf: mean free path Cr: constant volume specific heat ['d/to'j°C
]d: distance between walls Cm) Therefore, in the conventional example, the bubble skeleton diameter is 300 to 10
00 μm, a pressure of 10 mmHg or less, which is difficult to handle industrially, is required, which poses problems such as requiring large-scale equipment and long evacuation time in mass production. Furthermore, in the pressure range below 10-" rranHg, it is easily affected by the amount of gas released from the material, and in the case of this organic composition that tends to contain low molecular weight monomer components, there is a problem that the evacuation time is particularly long, making it difficult to mass-produce. It was inefficient.

In view of the above-mentioned problems, the present invention aims to shorten the evacuation time and enable mass production by obtaining excellent heat insulation performance in a low vacuum range that is industrially easy to handle.

Means to Solve the Problems The present invention involves adding 10 to 30 units of polyether polyol using an aromatic amine compound as an initiator to a benzylic ether type phenol resin, and further adding a catalyst, a foam stabilizer, and a blowing agent. A foam with an open cell structure obtained by mixing the foam with a cell communication agent is covered with a container made of metal or plastic laminate film, and the inside is depressurized.
It is sealed to provide insulation.

Function The present invention has the above-mentioned structure, and since the core material has a fine cell skeleton,
This core material is covered with a container made of metal-plastic laminate film, and when the inside is depressurized, 0.1 to 0,
01 +I! Excellent heat insulation performance can be obtained even at an industrially easy-to-handle pressure of about IIIHg, and mass production efficiency can be greatly improved by shortening the evacuation time.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, 4 is a hard phenol urethane foam that was foamed in a high-pressure urethane foaming machine using the raw materials shown in the table, cured, aged at room temperature, and then cut into a predetermined size.

In the table, phenol resin A is a benzylic ether type phenol resin synthesized from phenol and formaldehyde, and has a hydroxyl value of s vo 1!1iKOH/9. Polyol A is a polyether polyol obtained by addition polymerizing Po using aromatic amine as an initiator, and has a hydroxyl value of 460 ■KOH/litre. Foam stabilizer is Shin-Etsu Chemical■
The foaming agent was Flon R-11 manufactured by Showa Denko Corporation, the catalyst A was methylmorpholine, and the cell communication agent was calcium stearate manufactured by Nippon Oil & Fats Corporation. The organic polyisocyanate was crude M-DI (amine equivalent: 136) manufactured by Nippon Polyurethane.

Various combinations of these raw materials were foamed 1, some of which were used as examples for cups 1 and 2, and as comparative examples, No%A and B.
expressed. The density, open cell ratio, cell skeleton diameter, and compressive strength of the obtained hard phenolic urethane foam 4 are also shown in the table. Thereafter, the obtained hard phenolic urethane foam 4 was heated at 150°C for about 2 hours to evaporate the adsorbed moisture and swelling gas, and then covered with a container 6 made of aluminum-deposited polyester film, and the inside was heated at 0.0, 0.1, 1 mrHq. The pressure was reduced to 100%, and the mixture was sealed to obtain a heat insulator e. The evacuation time at this time was 6 minutes and 2 minutes for Examples A1 and 2, respectively, and 6 minutes and 2 minutes for Comparative Examples mA and B, respectively. The thermal conductivity of the obtained heat insulator e immediately after sealing is also shown in the table. The thermal conductivity was measured using K-Matic manufactured by Shinku Riko ■ at an average temperature of 24°C.

As is clear from the table, 10 to 30% of polyol A using an aromatic amine compound as an initiator is added to phenol resin A, and a catalyst, foam stabilizer 1 blowing agent, and cell communication agent are mixed. Obtained hard phenolic urethane 7
It was found that Ohm 4 had a finer cell skeleton and higher strength.

This is thought to be due to factors such as the compatibility of raw materials and the viscosity increase characteristic leading to resin curing, and the degree of crosslinking on strength, but the details of this process have not yet been elucidated. not present.

By using the hard phenolic urethane 4 with this fine cell skeleton as the core material of the heat insulator 6, the gas heat conduction in the heat insulator e is reduced to the same level as that of one with a larger cell structure even at high pressure. It exhibits excellent heat insulation performance at 0.1 to 0.01 rmHg, which is industrially easy to handle. As a result, since the evacuation time is short, mass production is easy, and pressure can be obtained with a simple evacuation device, which greatly contributes to productivity. In addition, since it can withstand atmospheric compression and will not deform or collapse in terms of strength, stable quality can be obtained.

It should be noted that if the bubble skeleton is made finer, the exhaust resistance increases and the exhaust time required to reduce the pressure to a predetermined pressure becomes longer, but in the 0.01 maHg range, there is no effect.
Furthermore, an influence appears at 0,001tpynHg where the molecular flow region dominates. Therefore, there is no problem with productivity by using a pressure of 0.1 to 0.01 msHg, which provides sufficient heat insulation performance even when miniaturized.

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

Obtained by adding and blending 10 to 30% of a polyether polyol using an aromatic amine compound as an initiator to a benzylic ether type phenol resin, and further mixing a catalyst, a foam stabilizer, a blowing agent, and a cell communication agent. Since open-cell foam has an extremely fine cell skeleton, it can be easily handled industrially by covering it with a container made of metal or plastic laminate film and reducing the internal pressure.
,01 Even at a pressure of +aHg, the heat conduction of the gas is sufficiently reduced, excellent heat insulation properties are obtained, and mass production is possible in a short time and with easy exhaust equipment, contributing to a significant improvement in productivity. .

In addition, the strength is improved by adding polyether polyol, and there is no deformation or collapse due to atmospheric compression, contributing to stable quality.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a hard phenolic urethane foam according to an embodiment of the present invention, FIG. 2 is a sectional view of the same heat insulating body, and FIG. 3 is a sectional view of a conventional heat insulating structure. 4...Hard 'fl phenolic urethane foam,
5...Container, 6...Insulator.

Claims (1)

[Claims] A polyether polyol using an aromatic amine compound as an initiator is added in an amount of 10 to 30% to a benzylic ether type phenol resin, and a catalyst, a foam stabilizer,
A heat insulator in which a foam with an open cell structure obtained by mixing a foaming agent and a cell communication agent is covered with a container made of metal or plastic laminate film, and the inside is sealed by reducing the pressure.