JP2776582B2 - Foam insulation - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam insulation material used for refrigerators, freezers, and the like.

2. Description of the Related Art In recent years, from the viewpoint of energy saving, there has been a need to reduce the thermal conductivity of foam insulation and improve heat insulation, and at the same time, to reduce the amount of CFC used as a foaming agent, and to reduce ozone depletion due to the influence of CFC. It is an extremely important theme to contribute to the improvement of environmental problems such as global warming.

For this reason, in the production of rigid urethane foam, which is a typical foam insulation material, various improvements have been made to polyols and organic polyisocyanates used as main raw materials, and foam stabilizers, catalysts, and foaming agents used as auxiliary materials. It has been done. Basically, in order to reduce the thermal conductivity of the rigid urethane foam, it is important to improve the gas thermal conductivity of the gas component in the gas bubbles. In particular, trichlorofluoromethane (hereinafter referred to as R-11) as a blowing agent ) Has been considered as an effective means to fill the R-11 gas and the foam bubbles. However, on the other hand, carbon dioxide gas obtained by the reaction between organic polyisocyanate and water can be used as a part of the blowing agent in order to reduce the amount of fluorocarbon used from the viewpoint of fluorocarbon pollution. However, in such a configuration, since the carbon dioxide gas remains in the cells of the foamed heat insulating material, the heat insulating performance of the foamed heat insulating material is low.

As an approach for solving such a problem, for example, a method of removing an impurity gas component with an adsorbent has been proposed as disclosed in JP-A-57-49628. That is, the adsorbent composed of zeolite or the like is preliminarily mixed into the raw material, and the carbon dioxide gas generated at the time of foaming is adsorbed and removed by the adsorbent. It has become.

Problems to be Solved by the Invention When considering the mechanism of purifying CFCs in gas in bubbles in JP-A-57-49628, first, a carbon dioxide adsorbent made of zeolite or the like is more than adsorbing carbon dioxide. Since water is preferentially adsorbed, in the reaction between water, which is a main carbon dioxide gas generating factor, and isocyanate, the water is immediately adsorbed to the adsorbent when the raw materials are mixed, and the generation of carbon dioxide gas itself does not occur. That is, even if the organic polyisocyanate to which the carbon dioxide adsorbent made of zeolite or the like is added in advance and the polyol component added with water is instantaneously mixed and foamed, at the time of the foaming start, the moisture already consists of zeolite or the like. It is adsorbed and dehydrated by a carbon dioxide adsorbent, and foaming is performed in the same form as freon alone foaming. Furthermore, the carbodiimide reaction generates a small amount of carbon dioxide in the polymerization process during foaming, but such gas is easily adsorbed, so that the gas inside the bubbles is purified and excellent heat removal performance is obtained. Can be

Therefore, JP-A-57-49628 discloses that the main C
The gas in the bubbles can be purified into Freon gas by removing the cause of O ₂ generation and removing a small amount of CO ₂ generated by the carbodiimide reaction, thereby improving the heat insulation performance.
However, in using carbon dioxide as a foaming gas, the amount of carbon dioxide generated is limited to a very small amount in the carbodiimide reaction, and as a result, there has been a problem that it is difficult to reduce the amount of fluorocarbon used. Therefore, the point of utilizing carbon dioxide gas as a foaming gas and the problem of purifying the chlorofluorocarbon in the gas within the gas bubbles, that is, reducing the amount of chlorofluorocarbon to solve the chlorofluorocarbon problem and achieving high heat insulation are both disclosed in Japanese Patent Application Laid-Open No. 57-49628.
However, the establishment of this technology is a major issue. The present invention has been made in view of the above circumstances, and provides a foamed heat insulating material that solves environmental problems such as ozone layer destruction without deteriorating the thermal conductivity of the foamed heat insulating material.

Means for Solving the Problems In order to solve the above problems, the present invention provides an isocyanate component obtained by adding and adsorbing an adsorbent composed of powdered activated carbon surface-treated with silicone; A premix component mixed with a foaming agent is mixed to obtain a thermally cut foam.

Action With the above configuration, the activated carbon powder surface-treated with silicone is inert to water, has no dehydration adsorption, and does not inhibit the reaction between water and the organic polyisocyanate. As a result, at the time of foaming, carbon dioxide gas obtained by the reaction between the organic polyisocyanate and water can be used, and the amount of the chlorofluorocarbon foaming agent can be reduced. Then, after foaming, carbon dioxide gas is adsorbed and removed by the hydrophobized powdered activated carbon, and the gas in the bubbles is purified into Freon gas. By such an operation, both reduction of the amount of chlorofluorocarbon used and improvement of the thermal conductivity are achieved, and it is possible to solve the environmental problems and the energy-saving conventionally contradictory technical problems.

Furthermore, the hydrophobicized powdered activated carbon dispersed in the foam insulation absorbs infrared rays of the heat transfer components and exchanges them for conduction heat transfer, resulting in an increase in thermal resistance. Contributes to the improvement of the heat insulation performance. Therefore, it is possible to provide an advantage that works more efficiently with respect to both the environmental problem and energy saving.

EXAMPLES Hereinafter, the foamed heat insulating material of the present invention will be described with reference to examples.

 The raw material formulation of one example is shown in the table.

Polyether A is an aromatic amine polyether having a hydroxyl value of 460 mg KOH / g, and foam stabilizer A is F-33 manufactured by Shin-Etsu Chemical Co., Ltd.
5. Catalyst A is Kaolyzer No. 1 manufactured by Kao Corporation, and the blowing agent is pure water and chlorofluorocarbon-11. Each raw material is mixed in a predetermined number of parts to constitute a premix component.

On the other hand, the isocyanate component is composed of organic polyisocyanate A composed of crude MDI having an amine equivalent of 135 and hydrophobized powdered activated carbon. The hydrophobized powdered activated carbon is prepared by adding 3 parts by weight of Shin-Etsu Chemical Co., Ltd. silicone KF-99 to 100 parts by weight of Morsibon 4A (powder activated carbon) Takeda Pharmaceutical Co., Ltd., and stirring and mixing at 100 ° C. while heating. A sample in which a silicone film was formed on the surface of the activated carbon powder was used.

The premix component thus prepared and the isocyanate component were mixed in a predetermined number of parts to obtain a foamed heat insulating material. The reactivity, density, thermal conductivity and bubble gas composition of the foamed heat insulating material at this time are shown in the table.

In addition, at the same time, as a comparative example, the case where no hydrophobized powdered activated carbon was added and the case where conventional powdered activated carbon Morsiebon 4A manufactured by Takeda Pharmaceutical Co., Ltd. was added are also shown in the table (Comparative Examples A and B).

As described above, it was found that the foamed heat insulating material of the present invention showed almost no carbon dioxide gas in the air bubbles, was filled with Freon gas, exhibited excellent heat insulating performance, and could reduce the amount of Freon used.
This is because hydrophobized powdered activated carbon is inactive in the adsorption reaction with water and does not hinder the reaction between organic polyisocyanate and water. This indicates that carbon dioxide was absorbed. Although the surface condition of the hydrophobized powdered activated carbon is unknown, a coating of a silicone resin is formed on the surface of the zeolite powder and serves as a barrier layer to the adsorbed gas. As a result, at least the time required for the reaction between water and isocyanate (about 10 (Seconds) is inert to water, and at the same time, has a characteristic of adsorbing carbon dioxide gas, which has a low adsorption speed but no practical problem. As a result, carbon dioxide gas generated by the reaction between water and isocyanate can be effectively used as a foaming gas, and can be reduced to a predetermined density even with a small amount of chlorofluorocarbon. In order to adsorb the powdered activated carbon, the carbon dioxide gas is finally removed, and the carbon dioxide gas is purified to CFC gas. As a result, the thermal conductivity of the gas is improved, and the thermal conductivity of the foam insulation becomes excellent.

In addition, the activated carbon hydrophobized powder dispersed in the foam insulation absorbs infrared rays from the heat transfer component of the heat transfer component and converts it into conductive heat transfer, resulting in an increase in thermal resistance. This contributes to the improvement of heat insulation performance.

As described above, the foamed heat insulating material of the present invention can reduce the amount of use of Freon-11, which is a main cause of environmental problems such as ozone layer destruction, and contribute to energy saving through excellent heat insulating performance. It can be realized and provided.

In the comparative example, when no hydrophobic powdered activated carbon was added, thermal conductivity was poor because a large amount of carbon dioxide gas was present as bubble gas, and when powdered activated carbon was added, water was instantaneously adsorbed and removed. As a result, there is no generation of carbon dioxide,
The density is high, and it can be predicted that the amount of CFC used will increase if foaming to the same volume. However, since the bubbles are purified by Freon gas, the thermal conductivity becomes excellent.

Effect of the Invention As described above, the present invention is to mix and stir a premix component comprising a polyether, a foam stabilizer, a catalyst, water and a fluorocarbon blowing agent, and an isocyanate component comprising a hydrophobized powdered activated carbon and an organic polyisocyanate, Since it is produced as a foamed heat insulating material, the carbon dioxide gas generated by the reaction between water and the organic polyisocyanate is effectively used as a foaming gas to reduce the amount of the chlorofluorocarbon foaming agent used. It is possible to adsorb and remove the carbon dioxide gas generated and remaining over time. Further, the activated carbon hydrophobized powder dispersed in the foamed heat insulating material absorbs infrared rays with respect to the radiant heat transfer among the heat transfer components and converts the heat into conductive heat transfer. To increase. As a result, gas heat conduction and radiation heat transfer in the bubbles are reduced, the thermal conductivity of the foamed heat insulating material is improved, and a foamed heat insulating material having excellent heat insulating performance can be provided. That is, it can contribute to solving the problem of chlorofluorocarbon pollution as well as energy saving.

Claims (1)

(57) [Claims] 1. A premix component comprising a polyether, a foam stabilizer, a catalyst, water, and a CFC blowing agent, and an isocyanate component comprising an organic polyisocyanate and a hydrophobized powder activated carbon surface-treated with silicone are mixed and stirred to form foam. Foam insulation.