JP2009063033A - Heat insulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat insulator improved in production efficiency and superior in heat insulating performance by using an adsorbent capable of adsorbing gas such as oxygen. <P>SOLUTION: The heat insulator 1 has a core material 4 composed of an inorganic fiber aggregate in which the adsorbent 2 is embedded, and covered by a shell material 3 composed of two laminate films. The shell material 3 is internally depressurized and sealed. The adsorbent 2 that seals a gas adsorbing material in a bag material having permeability is used. The gas adsorbing material is obtained by stirring cellulose in an aqueous sodium hydroxide solution, separating and drying solids, baking the solids at 673K under nitrogen gas stream, and performing vacuum heating treatment. The heat insulator 1 superior in production efficiency and heat insulating performance can be obtained by discharging gas in the shell material 3 using a vacuum pump to a certain degree of a vacuum, and adsorbing the remaining gas in the shell material 3 by the adsorbing material 2 and obtaining a predetermined degree of a vacuum. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat insulator that can be used as a heat insulator such as a refrigerator, a heat insulating container, a vending machine, an electric water heater, a heat storage container, an automobile, a railway vehicle, and a house.

  In recent years, energy saving is strongly desired from the viewpoint of preventing global warming, and energy saving is an urgent issue for household appliances. In particular, a heat insulation material having excellent heat insulation performance is required from the viewpoint of efficiently using heat in a heat insulation and cold insulation device.

  As general heat insulating materials, fiber materials such as glass wool and foams such as urethane foam are used. However, in order to improve the heat insulation performance of these heat insulating materials, it is necessary to increase the thickness of the heat insulating material, and there is a limit to the space that can be filled with the heat insulating material, so when space saving and effective use of the space are necessary It cannot be applied.

  Therefore, a vacuum heat insulator has been proposed as a high performance heat insulating material. This is a heat insulator in which a core material serving as a spacer is inserted into a jacket material having a gas barrier property and the inside is sealed under reduced pressure.

  By increasing the degree of vacuum inside the vacuum heat insulating body, high performance heat insulating performance can be obtained, but the gases existing inside the vacuum heat insulating body are roughly divided into the following three types. One is the gas that cannot be evacuated at the time of vacuum insulator fabrication, and the other is the gas generated from the core material and the jacket material after being vacuum-sealed (adsorbed on the core material and the jacket material) The other one is gas that passes through the jacket material and enters from the outside.

  In order to adsorb these gases, a method of filling a vacuum heat insulating material with an adsorbent has been devised.

  For example, there exists what adsorb | sucks the carbon dioxide and water | moisture content in a vacuum heat insulating body with the silica alumina etc. which are general purpose adsorption materials (for example, refer patent document 1).

  Moreover, there exists what adsorb | sucks the oxygen in a plastic container using a barium getter (for example, refer patent document 2). Among the gases to be adsorbed by the adsorbent in the vacuum heat insulating body, nitrogen and oxygen are examples of gases that are difficult to adsorb under reduced pressure, anhydrous content or low moisture. However, oxygen can be adsorbed by the Ba alloy, and the degree of vacuum inside the plastic container is maintained.

  Moreover, there exist some which consist of iron powder, an oxidation promoter, a filler, and a water | moisture-content donor as an oxygen absorber (for example, refer patent document 3).

This is an oxygen absorbent that is used for maintaining quality of foods, pharmaceuticals, etc., and moisture is required for oxygen absorption.
JP-A-61-103090 Japanese Patent Laid-Open No. 5-146672 Japanese Patent No. 3252866

  However, in the conventional configuration described in Patent Document 1, a gas such as oxygen that enters the heat insulating body cannot be adsorbed.

  Further, in the above-described conventional configuration described in Patent Document 2, it is necessary to melt the alloy under Ar reduced pressure for production, and the energy required for producing the material increases. Moreover, since it is an alloy, a weight increases, As a result, a product weight may become large.

  In addition, the conventional technique described in Patent Document 3 requires moisture for oxygen absorption, and cannot be used in an atmosphere that dislikes a small amount of moisture.

  This invention solves the said conventional subject, and it aims at providing the heat insulating body excellent in heat insulation performance and productivity by obtaining the adsorbent which can adsorb | suck oxygen etc.

  In order to achieve the above object, the heat insulator of the present invention is a heat insulator including at least a jacket material and an adsorbent capable of adsorbing a gas in the jacket material, wherein the adsorbent is at least It contains a substance obtained by carbonizing cellulose containing an alkali metal.

  Thereby, the cellulose can adsorb oxygen. Further, since it can be partially burned at a relatively low temperature, which is carbonization, the energy required for production is relatively small. Furthermore, an organic material derived from a natural product called cellulose may be used, and an environmentally friendly adsorbent can be obtained. Furthermore, it can be set as a comparatively lightweight adsorbent.

  By using such an adsorbent for the heat insulator, a gas such as oxygen in the heat insulator can be adsorbed, and productivity and heat insulation performance can be improved.

  That is, for example, the insulation can be efficiently produced by evacuating the outer cover material with a vacuum pump to a degree of vacuum that can be easily reached industrially, and then adsorbing the remaining gas with the adsorbent. Further, such a production method is particularly efficient for a heat insulator that has a large exhaust resistance and is difficult to be evacuated.

  In addition, it is possible to adsorb the gas or the like that has passed through the jacket material and entered from the outside over time, so that the reliability over time is improved.

  In another heat insulator of the present invention, the outer cover material is sealed under reduced pressure, and a container enclosing the adsorbent in the outer cover material and an opening member for opening the container are provided. It is characterized by having.

  By adopting such a configuration, a vacuum pump is used to evacuate to a predetermined degree of vacuum, and then the container in which the adsorbent is sealed is opened with the opening member, so that the main vacuum can be used in a necessary vacuum region. The performance of the adsorbent of the invention can be exhibited, and a heat insulator with high production efficiency and reliability can be obtained.

  The heat insulator of the present invention can adsorb a gas such as oxygen in the heat insulator and improve heat insulation performance. That is, it is possible to adsorb a gas or the like that has passed through the jacket material and enters from the outside with the lapse of time, thereby improving the reliability over time.

  Further, for example, a heat insulator with high production efficiency can be obtained by a method such as evacuating with a vacuum pump until a certain degree of vacuum, and then adsorbing residual gas with the adsorbent of the present invention to obtain a predetermined degree of vacuum. Can do it.

  The invention of the heat insulator according to claim 1 is a heat insulator including at least a jacket material and an adsorbent capable of adsorbing a gas in the jacket material, wherein the adsorbent includes at least an alkali metal. It contains the substance which carbonized the containing cellulose.

  As the alkali metal in the present invention, sodium and potassium are preferable. Carbonization of cellulose containing alkali metal is preferably partially carbonized, which is performed at a temperature of 773 K or less, and further performed under an inert gas atmosphere such as nitrogen or argon or under vacuum. It is desirable to use

  In addition, the substance obtained by carbonizing cellulose containing an alkali metal (gas adsorbing substance) preferably adsorbs at least oxygen, and can adsorb at least oxygen at 25 ° C. normal pressure or reduced pressure. Moreover, you may adsorb | suck gas other than oxygen. The gas adsorbed in addition to oxygen is not particularly specified.

  In the present invention, the method for measuring the adsorption amount is not particularly specified, and any known method such as an adsorption capacity method or a gravimetric method can be used as long as at least oxygen adsorption can be confirmed.

  In addition, the term “adsorption” as used herein includes absorption into the inside or sorption in addition to adsorption on the surface.

  Further, the adsorbent in the present invention can be adsorbed at normal temperature or lower, particularly in a low pressure region, at room temperature or in an atmosphere of about 80 ° C. or lower. Needless to say, adsorption in a region above normal pressure, or low or high temperature is also possible.

  Further, the usage form of the adsorbent may be a method of use such as powder, compression molding, pelletization, sheet form, thin film form, or accommodation in a separate container, but is not particularly specified.

  Further, as the jacket material, a container made of metal, plastic, glass or the like, or a plastic film, a laminate bag made of a laminate film having a metal, an inorganic substance, an oxide, carbon deposited on a plastic, a metal foil, or the like, or those Can be used.

  It is also possible to have a core material made of a porous body inside the jacket material.

  The core material made of a porous material is not particularly specified such as fiber, powder, foamed resin, thin film laminate, or a mixture thereof.

  In addition, such a heat insulating body creates a vacuum heat insulating space by inserting an adsorbent into the outer cover material, evacuating the outer cover material, and then sealing the outer cover material. Maintain the degree of vacuum in the coating material, or evacuate the coating material to a level that is industrially easy to reach, then seal the coating material, and remove the remaining gas in the coating material at that time By adsorbing with the adsorbent, it works like a two-stage pressure reduction, or the adsorbent is sealed in a separate container and the outer cover is evacuated to a predetermined pressure, and then the adsorbent is covered by some method. By making it possible to communicate with the inside of the material, it is possible to act like a two-stage decompression while keeping the adsorbent more highly active, but the usage method is not particularly specified.

  In addition to the adsorbent, an adsorbent capable of adsorbing moisture can be used in combination with the adsorbent.

  Examples of the adsorbent capable of adsorbing moisture include calcium oxide, magnesium oxide, strontium oxide, barium oxide, zeolite, silica gel, unsaturated fatty acid, iron and iron compound, but are not particularly specified. Multiple use is also possible.

  When using an adsorbent capable of adsorbing moisture together with a gas adsorbing substance, these are separately or mixed in the space in the jacket material, and are arranged as a powder or a molded body, or a breathable container, etc. It is conceivable to use these separately or mixed and enclosed, but it is not particularly specified.

  Further, the invention of the heat insulator according to claim 2 is the container according to claim 1, wherein the outer jacket material is hermetically sealed under reduced pressure, and the adsorbent is enclosed in the outer jacket material. And an opening member for opening the container.

  Here, the container may be a bag material, and the main component is preferably made of plastic in view of ease of opening and gas barrier performance. The plastic may be a single layer film or a multilayer film. Also, metal foil, metal, inorganic, or organic vapor-deposited products can be used.

  The opening member is not particularly specified as long as it can open the container, but for example, a protrusion is placed adjacent to the container so that a through-hole can be provided in the container made of a plastic film enclosing the adsorbent. When the external force is applied, a through hole can be formed in the container in the protrusion. Also, although the material is not specified, plastic or metal materials can be used.

  Alternatively, it can be opened by a switch based on magnetic force or temperature, but is not particularly specified.

  By evacuating the inside of the jacket material to a predetermined pressure by evacuation by a vacuum pump, and then opening the container in which the adsorbent is sealed by the opening member, the adsorbent can be used in a more effective pressure region.

  Moreover, as a usage method of the heat insulator, an inner box and an outer box are provided, the heat insulator is disposed in a space formed by the outer box and the inner box, and the space other than the heat insulator is filled with the foam heat insulator It can also be used as a box.

  The heat insulator can also be used for refrigeration equipment, cooling / heating equipment, cold storage vehicles, refrigerators using electronic cooling, and the like. It also refers to cold / hot equipment that uses hot and cold heat up to higher temperatures, such as vending machines. Moreover, the apparatus which does not require motive power, such as a gas apparatus, a thermal storage / cold storage container, or a cooler box, is also included.

  Furthermore, it can also be used in a higher temperature region for heat insulation / heat storage / heat insulation, such as a heat insulation / heat storage exterior material of a personal computer, a jar pot, a rice cooker, or an automobile engine.

  Furthermore, it can be used not only as a heat insulator but also as a structure requiring decompression or removal of oxygen or the like. For example, it can be used as a display that maintains a reduced pressure state or dislikes a specific component, for example, PDP, SED, organic EL, CRT and the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing a heat insulator in Embodiment 1 of the present invention.

  As shown in FIG. 1, the heat insulator 1 includes an adsorbent 2, a jacket material 3, and a core material 4, and the core material 4 in which the adsorbent 2 is embedded is covered with two jacket materials 3. The inside of the jacket material 3 is depressurized, and the jacket materials 3 on the outer periphery of the core material 4 are joined and sealed.

  Moreover, in this Embodiment, the laminated material which consists of a heat-fusion layer, a gas barrier layer, and a surface protective layer is used as the jacket material 3 in order from the inside, and the inorganic fiber aggregate is used as the core material 4.

  2, 3 and 4 are schematic cross-sectional views showing the adsorbent 2 of FIG.

  In Example 1, the adsorbent 2 shown in FIG. 2, the adsorbent 2A shown in FIG. 3 in Example 2, and the adsorbent 2B shown in FIG. 4 in Example 3 are used.

  2, 3, and 4, reference numeral 5 denotes a gas adsorbing substance that constitutes the adsorbent 2. 2, a reference numeral 6 indicates a bag material that houses the gas-adsorbing substance 5, and in FIGS. 3 and 4, a reference numeral 7 indicates a moisture-adsorbing material. They are stored together in the container 8, and the moisture adsorbing material 7 is located closer to the opening of the container 8 than the gas adsorbing substance 5.

  In the present embodiment (Examples 1 to 3), after stirring cellulose in an aqueous sodium hydroxide solution, the solid is separated and dried, fired at 673 K in a nitrogen stream, and further subjected to vacuum heat treatment. As a result, a gas adsorbing substance 5 was obtained. Further, it was confirmed that the oxygen adsorption amount of the gas adsorbing substance 5 was adsorbed from the vacuum part to the normal pressure part by the volume method.

  Moreover, when the intrusion gas component into the jacket material 3 was evaluated by an acceleration test, it was confirmed that the oxygen component accounted for 40 to 50%.

  The evaluation results of gas adsorption in the heat insulator 1 in which the kind of the adsorbent 2 is changed are shown in Examples 1 to 3. In each evaluation, the inside of the jacket material 3 in which the adsorbent 2 was allowed to stand was evacuated to about 50 Pa and sealed, and then the pressure change in the jacket material 3 was observed.

  Further, in Example 1 to Example 3, the heat insulator 1 was left for a predetermined time, and the adsorbent 2 in the jacket material 3 was taken out so as not to come into contact with the outside air. The adsorbent 2 was left in a closed system in an oxygen atmosphere, and the remaining capacity for oxygen adsorption of each adsorbent 2 was evaluated by observing the pressure change in the system.

Example 1
In Example 1, as the adsorbent 2, as shown in FIG. 2, a gas-absorbing substance 5 enclosed in a breathable bag 6 was used.

  By arranging the adsorbent 2 in the jacket material 3, the pressure change in the jacket material 3 takes about 2 hours to increase to a predetermined pressure as compared to the case without the adsorbent 2. The reliability over time of the heat insulation performance can be improved.

(Example 2)
In Example 2, as the adsorbent 2A, as shown in FIG. 3, the gas adsorbing substance 5 is put in the bottom of the container 8 having the upper surface as an opening, and the upper surface of the gas adsorbing substance 5 is adsorbed with water composed of calcium oxide. What was covered with the material 7 and compression-molded was used.

  After the adsorbent 2A is disposed in the outer jacket material 3, the pressure change in the outer jacket material 3 is about twice as long as the time required for the pressure to rise to a predetermined pressure compared to the case without the adsorbent 2B. Thus, it is possible to improve the reliability of the heat insulation performance over time.

  Moreover, when the residual capacity with respect to oxygen adsorption of the gas adsorbing substance 5 in the adsorbent 2A was evaluated after elapse of a predetermined time, it was confirmed that oxygen was adsorbed as compared with Example 1. This is because the surroundings are covered with the moisture adsorbing material 7 and the container 8 as compared with Example 1, and moisture and the like are adsorbed by the moisture adsorbing material 7, so that the load on the gas adsorbing substance 5 is reduced. It is done.

(Example 3)
In Example 3, as the adsorbent 2B, as shown in FIG. 4, the periphery of the compression-adsorbed gas adsorbing substance 5 was further covered with a moisture adsorbent 7 made of calcium oxide and compression-molded.

  After the adsorbing material 2B is disposed in the outer covering material 3, the pressure change in the outer covering material 3 is about twice as long as the time required to rise to a predetermined pressure as compared with the case without the adsorbing material 2B. Thus, it is possible to improve the reliability of the heat insulation performance over time.

  Moreover, when the residual capacity with respect to oxygen adsorption of the gas adsorbing substance 5 in the adsorbent 2B was evaluated after a predetermined time, it was confirmed that oxygen was adsorbed as compared with Example 1. This is thought to be because the load on the gas adsorbing substance 5 was reduced because the surroundings were covered with the moisture adsorbing material 7 as compared with Example 1, and moisture and the like were adsorbed by the moisture adsorbing material 7.

(Embodiment 2)
FIG. 5 is a schematic cross-sectional view showing a heat insulator in Embodiment 2 of the present invention.

  As shown in FIG. 5, the heat insulator 9 includes an adsorbent 2 </ b> C, a jacket material 3, a core material 4, and an opening member 10, and includes two core materials 4 in which the adsorbent 2 and the opening member 10 are embedded. The outer cover material 3 is covered and the inside of the outer cover material 3 is decompressed, and the outer cover materials 3 on the outer peripheral portion of the core material 4 are joined and sealed.

  In addition, the jacket material 3, the core material 4, and the gas adsorbing substance 5 are the same as those used in the first embodiment. Further, as the adsorbent 2C, a gas adsorbing substance 5 is vacuum-sealed in a non-breathable bag material (container) 11 is used.

  The opening member 10 is made of plastic, and one surface is convex and the other surface is concave, and the external surface pushing the convex surface is not applied, and the concave surface of the concave surface has a height equal to or slightly higher than the depth of the recess. The protrusion has a low height, and when an external force that pushes the convex surface is applied, the unevenness of the opening member 10 is reduced, and the height of the protrusion is deformable so as to be higher than the depth of the recess. When the adsorbing material 2C is arranged on a certain concave surface side and the convex surface is pushed with a force of about atmospheric pressure, the protruding portion of the opening member 10 comes into contact with the bag material 11 of the adsorbing material 2C, and eventually the bag material 11 to penetrate.

  The core material 4, the adsorbing material 2 </ b> C, and the unsealing member 10 are placed in the outer covering material 3, and the convex surface of the unsealing member 10 contacts the outer covering material 3, and the concave surface with the protruding portion of the opening member 10 is the adsorbing material After being inserted so as to be in contact with 2C, it is installed in a chamber connected to a vacuum pump, and the inside of the jacket 3 is decompressed and sealed by reducing the pressure in the chamber to 10 Pa with the vacuum pump. Got. Further, when the heat insulating body 9 is taken out from the chamber, the heat insulating body 9 is compressed to the atmosphere, an external force is applied to the opening member 10, a through hole is formed in the bag material 11, and the function of the gas adsorbing substance 5 of the adsorbing material 2C is expressed. .

  Compared with the heat insulator of the first embodiment, it is evacuated to a low pressure by a vacuum pump, and then the function of the gas adsorbing substance 5 of the adsorbent 2C is expressed. The application amount of the adsorptive substance 5 could be reduced.

  As described above, the heat insulator according to the present invention can improve the production efficiency and the heat insulation performance by making it possible to adsorb the gas in the heat insulator, and in particular, oxygen among them. It is capable of exhibiting performance, and can be applied to all types of heat insulation applications, such as hot / cold equipment such as refrigerators and refrigerators, and physical objects to be protected from heat and cold.

Schematic sectional view showing a heat insulator in Embodiment 1 of the present invention. Schematic sectional view showing Example 1 of the adsorbent used for the heat insulator of the same embodiment Schematic sectional view showing Example 2 of the adsorbent used for the heat insulator of the same embodiment Schematic sectional view showing Example 3 of the adsorbent used for the heat insulator of the same embodiment Schematic sectional view showing a heat insulator in Embodiment 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal insulator 2 Adsorbent material 3 Cover material 4 Core material 5 Gas-adsorbing substance 6 Bag material (container)
7 Moisture-absorbing material 8 Container 9 Heat insulator 10 Opening member 11 Bag material (container)

Claims (2)

  A heat insulator including at least an outer cover material and an adsorbent capable of adsorbing a gas in the outer cover material, wherein the adsorbent includes a substance obtained by carbonizing cellulose containing at least an alkali metal. And insulation.   The inside of the jacket material is sealed under reduced pressure, and has a container enclosing the adsorbent in the jacket material and an opening member for opening the container. Insulation.