JP2007211884A - Vacuum thermal insulation box body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability, and to improve productivity, in a vacuum thermal insulation box body having a double wall structure. <P>SOLUTION: This vacuum thermal insulation box body 1 has a vacuum thermal insulation structure by reducing pressure of a space 7, by arranging a core material 6 in the space 7 between an outer box 3 and an inner box 5. The vacuum thermal insulation box body 1 is characterized by arranging a gas adsorbing material 8 of setting a volume change within 50% before and after pressure reduction in the core material 6 and capable of adsorbing at least nitrogen. Thus, even if the box body 1 is compressed by atmospheric compression by pressure reduction, since the volume change in the core material 6 is small, deformation of the box body 1 can also be restrained, and the reliability is improved in restraining deformation and a crack. Gas remaining inside the box body 1 can also be adsorbed by the gas adsorbing material 8 capable of adsorbing the nitrogen, and production efficiency can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vacuum heat insulation box that can be used as a vacuum heat insulator for a refrigerator, a heat insulation container, a vending machine, an electric water heater, a vehicle, a house, or the like that requires heat insulation.

  In recent years, energy saving is desired because of the importance of preventing global warming, which is a global environmental problem, and energy saving is also promoted for consumer devices. In refrigerators, etc., heat entry is cut off and the operating rate of the refrigeration system is lowered, contributing to energy saving. In the heat-reserving liquid storage container that is built into the circulation system of an automobile engine, the heated and cooled water is kept warm and effectively used. By doing so, the combustion efficiency from the initial stage of engine operation can be secured. From the above viewpoint, the heat insulation performance improvement of the heat insulation box is calculated | required.

  In the case where heat conduction is performed through the presence of air, there is a mean free path of gas as a physical property affecting the heat insulation performance. The mean free path of a gas is the distance traveled until one of the molecules that make up the air collides with another molecule. If the void formed is larger than the mean free path, the molecules in the gap Collide and heat conduction by gas occurs, so that the thermal conductivity increases.

  The heat insulation principle of a vacuum heat insulator is to eliminate as much air as possible to transfer heat and reduce heat conduction by gas. On the other hand, when the void is smaller than the mean free path, the thermal conductivity is small. This is because there is almost no heat conduction due to air collision.

  As a means for solving such a problem, there is a vacuum heat insulating body constituted by a core material that holds a space and a jacket material that blocks the space and outside air. In general, powder materials, fiber materials, continuous foams, etc. are used as the core material, but in recent years, the demand for vacuum insulators has been diversified, and higher performance vacuum insulators. Is required.

  For example, a vacuum insulation panel manufacturing method, which is one of the vacuum insulation materials, covers a core material having a continuous structure such as rigid urethane foam made of open cells with a gas-barrier metal-plastic laminate film or the like, and vacuums the inside. After exhausting, it is packed into a panel (see Patent Document 1). When this is used for a heat-insulating box such as a refrigerator, it has a double structure in which it is attached to the inner surface of the box container material and foamed with urethane foam.

  In addition, a reservoir tank that is built into the circulation system of an automobile engine and keeps cooling water uses a metal vacuum double container as a heat insulating structure, and the cooling water is heated while being circulated as the engine operates. Is introduced into the main body of the heat insulating container through the partition wall, and after the engine stops, the temperature rising cooling water stagnating in the container is kept warm, and at the next engine start, the temperature rising cooling water is supplied to ensure combustion efficiency (patent) Reference 2).

In addition, in order to ensure heat insulation performance at a low degree of vacuum, the heat insulation space is filled with a heat insulating material such as fine particulate silica, and in order to increase the mechanical strength of the container, a support is provided between the inner container and the outer container. The provided vacuum heat insulation container is also proposed (refer to patent documents 3).
JP-A-7-293785 JP-A-10-71840 Japanese Patent Laid-Open No. 2001-128860

  In the configuration using the vacuum heat insulation panel of Patent Document 1, when trying to obtain a heat insulation box or container, a plurality of vacuum heat insulation panels can be used to form a cube or the like, but the curved surface, unevenness Molding is difficult. In addition, it is possible to improve the atypicality by using a small vacuum insulation panel, but it requires a lot of man-hours and becomes complicated, and there is no insulation between the vacuum insulation panel and the vacuum insulation panel, so that the insulation performance Is inferior, and by using a large number of sheets, the area increases and the heat insulation performance decreases.

  Moreover, in the structure of patent document 2, since it is comprised with the metal, there exists a problem that the heat leak through a metal material is large and the weight also becomes heavy. In addition, when the plate thickness is reduced in order to reduce the weight, the strength is reduced, so that there is a problem that the shape is limited to a shape capable of maintaining the strength, such as a cylindrical shape.

  Moreover, in the structure of patent document 3, although the intensity | strength is reinforced with the support body, a support body part does not have heat insulation, and heat leakage increases through a support body and heat insulation performance falls, so that there are many support bodies. Further, if the number of supports is small, the strength of the portion without the support decreases, distortion occurs, and if the state continues for a long time, cracks and breakage occur in the worst case. On the other hand, when the jacket material is made thicker, the thickness increases, so that the amount of heat leak increases and the space of the wall material increases, resulting in poor volumetric efficiency. Furthermore, since the support body is provided in the heat insulation space, it is considered that when exhausting by the vacuum pump at the time of manufacturing the heat insulation body, the exhaust resistance increases and the production efficiency deteriorates.

  An object of the present invention is a vacuum heat insulation box body that can have various shapes, and obtains a vacuum heat insulation box body that has less deformation of the container against atmospheric compression, that is, less cracking and the like, and has excellent heat insulation performance reliability. That is. Furthermore, it is obtaining the vacuum heat insulation box excellent in production efficiency.

  In order to achieve the above object, the vacuum heat insulating box of the present invention comprises an outer box and an inner box made of at least a gas barrier material, and a core material that is vacuum-sealed in a space constituted by the outer box and the inner box. A vacuum heat insulation box having a vacuum heat insulation structure comprising: a volume change rate before and after decompression of the core material of 50% or less, and a portion capable of ventilating at least a gas adsorbent capable of adsorbing nitrogen with the space It is characterized by being arranged in the above.

  Since the volume change rate of the core material is within 50%, even if the box body is compressed by atmospheric compression, the volume change of the core material is small, so that deformation and cracks of the box body can be suppressed, thereby causing the outside air to flow in. It is possible to suppress the deterioration of the heat insulation performance caused by. In particular, if the material constituting the box is thin and the strength is weak, the effect is high, and the box material can be made thin, so that the volumetric efficiency is also improved.

  Further, since the volume change of the core material is small, it is considered that the box material and the core material are in close contact with each other when the space between the inner box and the outer box is evacuated during the manufacture of the vacuum heat insulation box. . Therefore, the exhaust resistance between the box body and the core material is large, and it is necessary to evacuate for a long time in order to obtain a degree of vacuum only by exhausting with a general mechanical vacuum pump.

  Therefore, by providing a gas adsorbent capable of adsorbing at least nitrogen as in the present invention, it can be efficiently manufactured even in a vacuum heat insulating box with a small volume change of the core material. Furthermore, since the gas which invades from the outside with time can be adsorbed, it is possible to obtain a vacuum heat insulation box having excellent reliability. In particular, when at least a resin is used, since the gas entering from the outside increases, the effect is improved.

  Nitrogen is a gas having a triple bond and low activity, and it is difficult to adsorb with a general-purpose gas adsorbent.

  The gas adsorbent according to the present invention, characterized in that it has at least Li, a transition metal that does not form an intermetallic compound with Li, and the enthalpy of mixing of the two metals is greater than 0, and at least Li By using a gas adsorbent characterized by having a solid substance having a hardness of 5 or more at 25 ° C., nitrogen can be adsorbed at normal pressure or reduced pressure.

  According to the present invention, since the volume change of the core material is small even when the box is compressed by atmospheric compression, deformation and cracks of the box can be suppressed, and a highly reliable heat insulating box can be obtained, and nitrogen can be obtained. By using an adsorbing material capable of adsorbing, a vacuum heat insulating box body excellent in productivity can be obtained even if the heat insulating box body has a small volume change of the core material and poor exhaust efficiency.

  The invention of the vacuum heat insulation box according to claim 1 includes an outer box and an inner box made of at least a gas barrier material, and a core material that is vacuum-sealed in a space formed by the outer box and the inner box. A vacuum heat insulation box having a vacuum heat insulation structure, wherein the core material has a volume change rate before and after depressurization of 50% or less, and at least a gas adsorbent capable of adsorbing nitrogen is disposed in the space and a portion that can be vented. It is characterized by providing.

  Here, the volume change rate of the core material means, for example, a core material that has been compressed in the atmosphere by reducing the pressure when the core material is sealed in a bag having a high gas barrier property such as a laminate film bag, and the core before the pressure is reduced. It is the rate of change of the core material volume that has decreased with respect to the material volume. At this time, for example, the volume of the core material taken out from the vacuum heat insulating box is measured, and then the volume of the vacuum heat insulating material in which the same core material is inserted, decompressed and sealed in the plastic laminate film is measured, and the volume change rate is 50. % Or less may be used.

  According to the present invention, since the volume change rate is 50% or less, even if the box is compressed by atmospheric compression, the volume change of the core material is small, so that deformation of the box can also be suppressed, and deformation and cracking can be prevented. Reliability can be improved by the suppression. In particular, if the material constituting the box is thin and the strength is weak, the effect is high, and the box material can be made thin, so that the volumetric efficiency is also improved.

  In addition, the smaller the volume deformation rate, the thinner the outer box and inner box can be made, and even materials with inferior extensibility and strength can be used, resulting in space saving and material reduction effects. In order to maintain long-term reliability, the volume change rate is desirably 20% or less.

  In order to prevent surface deformation almost completely and make the appearance more beautiful, the volume change rate is more preferably 5% or less.

  On the other hand, if the volume change rate is larger than 50%, if the box body is greatly deformed, the appearance is remarkably impaired, and cracks, dents, distortion, etc. occur in the outer box and the inner box, and the outside air flows in. Insulation effect may be lost. Deterioration of cracks and the like is not limited to those occurring at the time of decompression, but also includes the phenomenon that deformation and cracks occur due to stress applied for a long period of time.

  It is possible to increase the strength by increasing the thickness of the inner box and outer box materials, but the volume efficiency is reduced and the cost is increased. Furthermore, since the cross-sectional areas of the inner box and outer box materials increase, the amount of heat that flows from the inner box and outer box materials increases, and the heat insulation performance also decreases.

  The material of the outer box and the inner box is not particularly specified, and a resin material, a metal material, an inorganic material, or a mixed material thereof can be used.

  Conventionally, in order to suppress the intrusion gas from the outside and improve the reliability of the heat insulation performance of the heat insulation box, a high gas barrier material is required for the outer box or the inner box. Intrusion gas can be adsorbed by a gas adsorbent capable of adsorbing at least nitrogen, and is not particularly specified, and general-purpose resins can also be used.

Further, when it is desired to suppress the amount of adsorption used due to cost or the like, the outer box or the inner box has an air permeability, nitrogen permeability, or oxygen permeability at 30 ° C. of 100 [cm ³ / m ² · day · atm. ], More preferably 10 [cm ³ / m ² · day · atm] or less. When the air permeability exceeds 100 [cm ³ / m ² · day · atm], the amount of air entering from the outside increases, and even if it is supported by air adsorption by the adsorbent, the necessary amount of adsorbent increases and adsorption The solid thermal conductivity of the material may increase and the heat insulation performance may decrease.

  Also, the molding method is not limited, but blow molding, injection molding, vacuum molding, and pressure molding are most easily molded, and any molding method may be used. Moreover, you may combine these shaping | molding methods.

  The core material is not particularly limited as to the material system, and is not particularly limited to organic or inorganic fibers, powder, solidified powder, foamed resin, and the like.

  For example, in the case of a core material using fibers, inorganic fibers such as glass wool, glass fibers, alumina fibers, silica alumina fibers, silica fibers, rock wool, silicon carbide fibers, natural fibers such as cotton, synthetic fibers such as polyester and nylon, etc. Known materials such as organic fibers can be used.

  In order to use the fiber, there are methods such as compression or heat compression of the fiber, compression or heat compression using water or a binder, needling, spunlace, and papermaking.

  On the other hand, in the core material using powder, inorganic powder such as silica, pearlite and carbon black, organic powder such as synthetic resin powder, or a mixture thereof is filled as it is or filled into a breathable bag. Or solidifying with a fiber binder or an inorganic or organic liquid binder. In the foamed resin, urethane foam, phenol foam, styrene foam, or the like can be used.

The gas adsorbent capable of adsorbing at least nitrogen preferably adsorbs nitrogen of 1 cm ³ / g or more, more preferably 3 cm ³ / g or more, more preferably 5 cm ³ / g or more at normal pressure or reduced pressure. It is also desirable to adsorb oxygen, moisture, carbon dioxide and the like. Further, it is desirable to adsorb these at 100 ° C. or less, more preferably at room temperature.

  The gas adsorbent is not particularly specified for physical adsorption, chemical adsorption, adsorption, absorption, sorption, occlusion, and the like.

  Further, the gas adsorbent can be used as a powder or a molded body, but is not particularly specified. In addition, the molded gas adsorbent can be used in the form of compression molding, tableting, pelletizing, etc., or the powder in a separate container and the powder in the container compressed Further, the gas adsorbent may be covered with another gas adsorbent.

  As for the method of using the gas adsorbent, the vacuum heat insulation box is evacuated in a state where the vacuum heat insulation box and the container containing the gas adsorbent can be vented, and then the vacuum heat insulation box is sealed. By creating a vacuum heat insulation space and maintaining the degree of vacuum in the structure with a gas adsorbent, or evacuating the structure to a level that is industrially easy to reach, then sealing the structure, By adsorbing the gas in the remaining structure with a gas adsorbent, it works like a two-stage decompression, or the gas adsorbent is sealed in a separate container and the heat insulating body is evacuated to a predetermined pressure, By allowing the gas adsorbent to communicate with the structure in some way, it is possible to work like a two-stage pressure reduction while keeping the gas adsorbent more highly active. What to specify No.

  Also, the adsorbent placement locations may be placed at one location, or at multiple locations to further improve production efficiency.

  Further, it is possible to remove the gas adsorbent during recycling or the like.

  The invention of the vacuum heat insulation box according to claim 2 is characterized in that the core material in the invention according to claim 1 has a three-dimensional shape.

  For example, when injecting into a space such as a powder material, if the space has a complicated shape, unevenness occurs in the unfilled portion and packing density, resulting in uneven performance and volume change rate, and heat insulation performance and volume change rate. There is a risk of variation. However, since the core material has a three-dimensional shape, the non-filled portion and filling density unevenness can be eliminated, and the core material can be filled with high dimensional accuracy, and has uniform heat insulation performance and volume change rate. Can do.

  In addition, even for core materials that are difficult to fill after box molding, such as inorganic fiber materials, it is possible to sandwich the core material between the outer box and the inner box by simplifying the construction method. Can be achieved.

  The invention of the vacuum heat insulation box according to claim 3 is characterized in that the three-dimensional core material in the invention according to claim 2 is divided into at least two.

  By dividing the three-dimensional core material into two or more, even if it has a complicated shape and is difficult to form by a single molding, it can be easily produced.

  Further, in a material having thermal conductivity anisotropy such as a fiber material, it is important to align the core material direction in a direction in which the heat insulation performance is improved.

  The invention of the vacuum heat insulation box according to claim 4 is characterized in that the gas barrier material of the outer box or the inner box according to any one of claims 1 to 3 is a resin material and a metal foil. It is characterized by being multi-layered.

  Metal foil has a higher gas barrier property than a resin material having a high gas barrier property, and can greatly increase the gas barrier property of the resin material, as well as increase the load on equipment and processes, such as vapor deposition and plating. However, it is possible to easily form multiple layers at the time of molding like insert molding. Furthermore, by using the foil, it is possible to minimize heat leakage due to the wraparound of the outer box and the inner box.

  In addition, the resin barrier alone may cause the gas barrier properties to decrease as the temperature increases.On the other hand, the heat leak increases and the heat insulation performance decreases with the metal material alone. In addition to improving gas barrier properties, heat leak can also be reduced and applied.

  Further, the gas barrier property becomes better as the area that is multilayered with the metal foil is larger.

  Further, the metal foil is less dependent on temperature and humidity, and can have better gas barrier properties against environmental changes.

  Further, the metal foil does not need to be a single metal, and a multilayer film with a resin material such as a laminate film may be used in order to improve adhesion and handling. Moreover, even if it is the vapor deposition film which vapor-deposited the metal on the resin material, since the same effect is acquired, there is no problem.

  Moreover, you may provide the surface protective layer for prevention of a pinhole etc. on the surface of metal foil and a metal vapor deposition film as a multilayer film. As the surface protective layer, a polyethylene terephthalate film, a stretched product of polypropylene film or the like can be used, and if a nylon film or the like is further provided on the outer side, flexibility is improved.

  In addition, if the metal becomes too thick, heat leaks through the metal foil, so 1 mm or less is desirable. Further, if it is too thin, it may be broken at the time of molding, and pinholes are also easily formed.

  The metal foil may be made of any material such as aluminum, stainless steel, iron and copper, but aluminum foil is most desirable from the viewpoint of workability and cost.

  In addition, it is preferable to cover the entire surface of the metal foil. For example, the metal foil is not wrinkled and is not easily damaged, and a corner portion or the like is not covered. . Therefore, by forming a multilayer with the gas barrier material, it is possible to reinforce the gas barrier property of the portion that cannot be covered with the metal foil and maintain the heat insulating property of the vacuum heat insulating box for a long period of time.

  In addition, metal foil is usually placed on the mold side and insert molding or in-mold molding is performed. If a three-dimensional core material using a material with a small volume reduction rate is used, the metal foil is attached to the core material side. It becomes possible to install, and the degree of freedom of molding of the resin material is remarkably improved. Furthermore, since the volume reduction rate of the core material is as small as 50% or less, even if the box and the core material are deformed by atmospheric compression, the portion where the metal foil is damaged is remarkably small, and the gas barrier property can be secured.

  In addition, a film obtained by vapor-depositing a metal material on a resin material has a low degree of crystallinity unlike metal foil, and thus can be easily stretched and a better multilayer material can be formed.

  Further, a gas barrier property may be improved by forming a vapor deposition film of an inorganic oxide such as silica or alumina on the resin material.

  Further, as a resin material, ethylene-vinyl alcohol copolymer, polyacrylonitrile, nylon 6, nylon 66, nylon 12, polybutylene terephthalate, polybutylene naphthalate, polyethylene terephthalate, polyethylene naphthalate, polyvinylidene fluoride, polyvinylidene chloride, It is preferable to use at least one from the group consisting of ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, polyimide, polycarbonate, polyacetate, polystyrene, ABS, polypropylene, polyethylene, polyphenylene resin, Absent.

  Furthermore, it becomes possible to reduce the multilayered portion with the metal foil, for example, it is possible to maintain an equivalent gas barrier property even in a vacuum heat insulating box with a complicated shape that is difficult to multilayer the metal foil, Freedom formation can be improved.

  Further, even if the thickness of the resin material is reduced, it is possible to have the same gas barrier property, and space saving can be achieved.

  The invention of the vacuum heat insulation box according to claim 5 is characterized in that the gas adsorbent capable of adsorbing nitrogen in the invention according to any one of claims 1 to 4 is at least between Li, Li and metal. It has a transition metal that does not form a compound, and the enthalpy of mixing of the two metals is greater than zero.

  It is a metal that does not form an intermetallic compound with each other, and a metal having an enthalpy of mixing of the two kinds of metals that is greater than 0 and that normally has no interaction, is included in the metal. It is possible to improve the activity of the metal. Accordingly, the reactivity between the metal and the gas is improved and the gas adsorption activity is increased.

  Examples of transition metals having a mixed enthalpy greater than 0 with Li include Co, Cr, Cu, Fe, Hf, Mn, Mo, Nb, Ni, Ta, Ti, V, W, Y, and Zr.

  Moreover, it is desirable that Li and at least a part of the transition metal are compatible.

  That at least a part is compatible means a state in which at least a part cannot physically separate two kinds of substances. For example, a state in which a part of the boundary surface between two kinds of substances is mixed with each other at the atomic level is not limited to this.

  By mixing at least a part between Li and the transition metal so as to cause compatibility, the repulsive force between the metals can be further increased, and the activity of the metal contained therein can be improved. Therefore, the reactivity with the gas is improved and the gas adsorption activity is increased.

  The invention of the vacuum heat insulation box according to claim 6 is characterized in that the gas adsorbent capable of adsorbing nitrogen in the invention according to any one of claims 1 to 4 has at least Li and a hardness at 25 ° C. It is characterized by having a solid substance which is 5 or more.

  While the hardness of Li is 0.6, it is possible to regenerate the active surface by scraping the Li surface by coexisting a solid substance with a hardness of 5 or more and grinding Li and the substance. And Li can be subdivided. Therefore, nitrogen can be adsorbed at room temperature by increasing the specific surface area of Li and activating it.

Further, it is preferable to use a substance having a density of 5 g / cm ³ or less, so that the density increase is small even when combined with Li having a density of 0.53 g / cm ³ , for example, when the gas adsorbent is incorporated into a product. There is little increase in weight.

Examples of the solid substance having a hardness of 5 or more include Si, B, c-C, SiO ₂ , SiC, c-BN, Al ₂ O ₃ , MgO and the like.

  Moreover, it is desirable that Li and at least a part of the solid substance are compatible.

  That at least a part is compatible means a state in which at least a part cannot physically separate two kinds of substances. For example, a state in which a part of the boundary surface between two kinds of substances is mixed with each other at the atomic level is not limited to this.

  Invention of the vacuum heat insulation box of Claim 7 manufactured that the gas adsorbent which can adsorb | suck the said nitrogen in the invention of Claim 5 or 6 was included at least by the mixing process by mechanical alloying. Features.

  By mechanical alloying, the effect of the above compatibility can be effectively obtained. In addition, Li and the transition metal, or Li and the solid substance can be ground and mixed with high energy, the effect of scraping Li by the solid is increased, and the Li new surface exposure and fragmentation effects are increased. Further, since the solid substance is also cut and subdivided, it becomes more effective for subdividing Li.

  In addition, mechanical energy is accumulated in Li or the solid substance by mechanical alloying, and the energy possessed after mechanical alloying is higher than the energy possessed at the starting point, and it is considered that the energy is further increased.

  Further, in order to produce a highly active gas adsorbent, it is preferable to perform mechanical alloying in an inert gas, for example, in an atmosphere of Ar, He, or the like, or under vacuum.

  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 an external view of a vacuum heat insulation box according to Embodiment 1 of the present invention, and FIG. 2 is a schematic view of a vacuum heat insulation box according to Embodiment 1. FIG. 3 is a longitudinal sectional view of the vacuum heat insulation box in the first embodiment.

  A vacuum heat insulation box 1 having a hot water storage structure in which hot water or water is stored inside has an inlet 2 for storing water or the like in the upper part, and an outer box 3 on the outside to reduce the heat insulation space. There is an exhaust port 4 for this purpose.

  In the schematic diagram of FIG. 2, the inner box 5 having the inlet 2 has a three-dimensional shape, the core material 6 divided, the outer box 3 divided further outside, and the exhaust port for exhausting the heat insulation space to the outer box 3. It is composed of four.

  The outer box 3 is cut in half when integrally molded, and is used as it is when divided and molded. Solidified into the same three-dimensional shape as the space between the inner box 5 and the outer box 3, and further divided core material 6 and the inner box 5 are inserted into the inside, and the neck of the inlet 2 of the outer box 3 and the inner box 5. Each part is welded. Thereafter, the outer box 3 cut in half is welded at the cut portion and sealed, and then the pressure is reduced from the exhaust port 4 to produce a vacuum heat insulating box.

  In order to insert the core material 6 into the inner box 5, it is easier to insert the core material 6 into two or more parts. Further, the more complicated the shape is, the easier it is to form the box by dividing and inserting it. If the joint between the core material and the core material is in close contact, the heat insulation performance and the strength of the box body are not greatly affected.

  The outer box 3 may be welded by welding the end surfaces. However, if the flange portion is formed in advance, the outer box 3 can be welded easily.

The welding method is not particularly limited, but vibration welding, ultrasonic welding, laser welding, IRAM, DSI, welding, hot melt, electromagnetic induction, hot air welding, impulse welding, hot air welding, near red welding, diffusion bonding Etc. are used. A combination of these may also be used.
In the longitudinal sectional view of FIG. 3, the vacuum heat insulating box 1 is composed of an outer box 3 and an inner box 5, and a heat insulating space 7 exists between the outer box 3 and the inner box 5. The inside of the heat insulation space is filled with the core material 6 and has a gas adsorbent 8 and a moisture adsorbent 9.

  The heat insulating space 7 is exhausted from the exhaust port 4 to become a decompressed space, and then sealed by sealing the exhaust port 4.

  The gas adsorbing material adsorbs the gas entering from the material constituting the box, the adsorbing gas remaining inside, etc., and can ensure long-term reliability.

  As the gas adsorbent, an adsorbent capable of adsorbing oxygen, nitrogen, water, carbon dioxide, hydrogen and the like can be used alone or in combination.

  The core material 6 has a volume reduction rate of 50% or less indicating the ratio of the volume before decompression due to atmospheric compression under reduced pressure, and the vacuum heat insulating box 1 is made of the core material even if the heat insulating space 7 is decompressed. Since it does not deform beyond volume reduction, the load on the inner and outer box materials is reduced, so that cracks, cracks and deformation due to atmospheric compression are unlikely to occur, and a vacuum heat insulating box with high box strength and high reliability Can be configured. In particular, when the inner box and outer box materials have lower rigidity than atmospheric compression, or when the material thickness is thin, the effect is great. In addition, fatigue failure occurs due to stress applied over the long term, and the inner box and outer box materials deteriorate due to the external environment and the rigidity decreases, causing cracks and cracks. If it is 50% or less, it will not be deformed more than the volume reduction of the core material.

Example 1
The inner box is a multilayer material made of polypropylene having a thickness of 1 mm and an ethylene-vinyl alcohol copolymer (EVOH) having a thickness of 100 μm. The polypropylene is on the inside, and molding is performed by blow molding. Polypropylene and EVOH are bonded with a bonding material (10 μm). The outer box is a multi-layer material consisting of high density polyethylene with a thickness of 1 mm and EVOH with a thickness of 100 μm. The high density polyethylene is on the outside. Like the inner box, the outer box is made by blow molding. 10 μm). The outer box formed by blow molding is cut in half, and a core material solidified into the same three-dimensional shape as the space between the inner box and the outer box is inserted. The core material is prepared by press-molding glass fibers having an average fiber diameter of 5 μm at 500 ° C., adjusting the density to 250 kg / m ³ , and dividing the glass fiber into two parts. Then, the inner box is inserted inside, and further a gas adsorbent and a moisture adsorbent are inserted.

  The gas adsorbent was a powder obtained by mechanically alloying Li and Fe in an Ar atmosphere, and the moisture adsorbent was calcium oxide.

  As an evaluation of the amount of nitrogen adsorbed by this gas adsorbent, the gas adsorbent was enclosed in a test tube with a cock in an Ar atmosphere, then the inside of the test tube was taken out from the Ar atmosphere, evacuated from the cock, and filled with nitrogen. When the nitrogen adsorption amount of the gas adsorbent was read from the decrease in the nitrogen pressure, it was 5 cc / g.

  The outer box and the inner box are welded at the neck portion of the injection port, and the outer box cut in half is welded at the cut portion, sealed, and then depressurized from the exhaust port to produce a vacuum heat insulation box.

  The core material produced under the same conditions as the inserted core material, or the core material used in the vacuum heat insulation box was taken out and measured in volume, then placed in a laminate film and the volume after reduced pressure was measured. It was 3.3%. The produced vacuum heat insulation box body was better than Comparative Example 1 without any noticeable change in appearance. Further, the thermal conductivity is 0.0030 W / mK, which is higher than that of Comparative Example 1 and has high heat insulation performance.

  Further, to reach a thermal conductivity of 0.0030 W / mK, 30 minutes was required only with the vacuum pump as in Comparative Example 2, but the gas adsorbent was evacuated with a vacuum pump for 3 minutes and then left to stand. The thermal conductivity could be reached just by placing.

  Moreover, although the vacuum heat insulation box was left to stand at 40 degreeC for 3 months, the change of the external appearance and performance was not seen compared with the comparative example 1 again. Further, the heat insulation performance after 3 months at 40 ° C. was measured, but no deterioration was observed.

(Example 2)
The inner box is a multilayer material made of ABS resin having a thickness of 0.3 mm and an ethylene-vinyl alcohol copolymer (EVOH) having a thickness of 100 μm. The ABS is on the inside, and molding is performed by blow molding. Further, the ABS resin and EVOH are bonded with a bonding material (10 μm). The outer box is a multilayer material consisting of high density polyethylene with a thickness of 1 mm and EVOH with a thickness of 100 μm. The high density polyethylene is on the outside and is produced by double injection molding. The high density polyethylene has a bonding material with EVOH. It is mixed. When molding by injection molding, the core material is molded in half and solidified into the same three-dimensional shape as the space between the inner box and the outer box. In addition, a flange portion is provided to facilitate the joining. The core material is prepared by mixing 10 wt% carbon black and 10 wt% glass fiber having an average fiber diameter of 5 μm with dry silica and dry silica having an average primary particle diameter of 7 nm, and press-molding them into a space shape. The density was solidified to 260 kg / m ³ . In addition, it is divided into four parts of a side surface, a bottom surface, and a top surface so that it can be inserted, and is molded and inserted. Then, the inner box is inserted inside, and further a gas adsorbent and a moisture adsorbent are inserted.

As the gas adsorbent, a powder obtained by mechanically alloying Li and Al ₂ O ₃ in an Ar atmosphere was used, and as the moisture adsorbent, calcium oxide was used.

  The outer box and the inner box are welded at the neck portion of the injection port, and the outer box cut in half is welded at the cut portion, sealed, and then depressurized from the exhaust port to produce a vacuum heat insulation box.

  As a result of measuring the volume of the core material produced under the same conditions as the inserted core material, and then measuring the volume after depressurization, the volume reduction rate was 8.5%. The produced vacuum heat insulation box body was better than Comparative Example 1 without any noticeable change in appearance. In addition, the thermal conductivity is 0.0045 W / mK, which is higher than that of Comparative Example 1.

  In addition, it took 30 minutes with a vacuum pump alone to reach a thermal conductivity of 0.0045 W / mK. However, with the gas adsorbent, it was evacuated with a vacuum pump for 3 minutes and then left as it was. I was able to reach the rate.

  Moreover, although it was left to stand at 40 degreeC for 3 months, the change of an external appearance and a performance was not seen compared with the comparative example 1 too. Further, the heat insulation performance after 3 months at 40 ° C. was measured, but no deterioration was observed.

(Example 3)
The inner box is a multilayer material made of ABS resin having a thickness of 0.3 mm and an ethylene-vinyl alcohol copolymer (EVOH) having a thickness of 100 μm. The ABS resin is on the inside, and molding is performed by blow molding. Further, the ABS resin and EVOH are bonded with a bonding material (10 μm). The outer box is a multilayer material consisting of high density polyethylene with a thickness of 1 mm and EVOH with a thickness of 100 μm. The high density polyethylene is on the outside and is produced by double injection molding. The high density polyethylene has a bonding material with EVOH. It is mixed. When molding by injection molding, mold in half and insert the inner box. In addition, a flange portion is provided to facilitate the joining. Then, the inner box is inserted inside, and further a gas adsorbent and a moisture adsorbent are inserted.

  The gas adsorbent was a powder obtained by mechanically alloying Li and MgO in an Ar atmosphere, and the moisture adsorbent was calcium oxide.

The outer box and inner box are welded at the neck portion of the inlet, and the outer box cut in half is welded at the cut portion and sealed. Thereafter, a powdery core material is sealed from the exhaust port. The core material used was a mixture of dry silica having an average primary particle diameter of 25 nm and 5 wt% carbon black with respect to dry silica. From the space volume and the amount enclosed, the density was 150 kg / m ³ . Thereafter, the pressure is reduced from the exhaust port to produce a vacuum heat insulation box.

  The gas adsorbent is sealed in a bag in an Ar atmosphere, and after the space between the outer box and the inner box is depressurized, the bag enclosing the gas adsorbent is opened so that the space can be vented. did.

  The inserted core material was put into a laminate film, the volume after depressurization was measured, and the volume before depressurization was calculated from the encapsulation density. As a result of calculation, the volume reduction rate was 25%. This is thought to be because the core material could not be fully enclosed because the powder with a high gas phase rate was enclosed from the narrow mouth, but the produced vacuum heat insulation box had no noticeable change in appearance and compared with Comparative Example 1. It was good. Further, the thermal conductivity is 0.0050 W / mK, which is higher than that of Comparative Example 1.

  In addition, it took 30 minutes with a vacuum pump alone to reach a thermal conductivity of 0.0050 W / mK. However, with the gas adsorbent, it was evacuated with a vacuum pump for 3 minutes and then left as it was. I was able to reach the rate.

  Moreover, although it was left to stand at 40 degreeC for 3 months, the change of an external appearance and performance was not seen and it was favorable compared with the comparative example 1. Further, the heat insulation performance after 3 months at 40 ° C. was measured, but no deterioration was observed.

(Embodiment 2)
FIG. 4 is a longitudinal sectional view of the vacuum heat insulation box in the second embodiment of the present invention.

  In the longitudinal sectional view of FIG. 4, the vacuum heat insulating box 10 is composed of an outer box 11 and an inner box 12, and a heat insulating space 7 exists between the outer box 11 and the inner box 12. Metal foil 13 is insert-molded inside the outer box 11 and outside the inner box 12. The inside of the heat insulating space 7 is filled with a core material 14 and has a gas adsorbing material 8. The heat insulating space 7 is exhausted from the exhaust port 4 to become a decompressed space, and then the exhaust port 4 is sealed to form a sealed space.

Example 4
The inner box is a multilayer material having a structure in which two 100 mm thick ethylene-vinyl alcohol copolymers (EVOH) are sandwiched between two 0.5 mm thick polypropylenes, and molding is performed by blow molding. Polypropylene and EVOH are bonded with a bonding material (10 μm). A metal foil made of a multilayer material of nylon (10 μm), aluminum foil (20 μm) and polypropylene (7 μm) is placed on the flat surface of the inner surface of the mold at the time of blow molding and integrated into the inner box at the same time as molding. Perform insert molding. The metal foils nylon and aluminum, and aluminum and polypropylene are joined together by a joining material (5 μm). In addition, the metal foil joins the polypropylene side to the inner box.

  The outer box is a multilayer material made of high-density polyethylene having a thickness of 1 mm and an ethylene-vinyl alcohol copolymer (EVOH) having a thickness of 100 μm, and is manufactured by dividing by double injection molding. Polyethylene is mixed with a bonding material to improve adhesion with EVOH. The metal foil is a multilayer material of nylon (10 μm), aluminum foil (20 μm), and polyethylene (7 μm), and is placed on the mold flat part at the time of injection molding and insert molded. The metal foils nylon and aluminum, and aluminum and polyethylene are joined together by a joining material (5 μm). Further, the metal foil joins the polyethylene side to the outer box. The outer box is preliminarily molded into two parts so that the inner box and the core material can be inserted and joined, and a flange is provided at the joint.

  Moreover, the coverage with the metal foil was 80% of the total surface area.

And the core material solidified in the same three-dimensional shape as the space between an inner box and an outer box is inserted. The core material is a glass fiber having an average fiber diameter of 7 μm, a water glass aqueous solution is applied as a binder, dried, pressure-molded at 500 ° C., adjusted to a density of 270 kg / m ³ , and divided into two parts and inserted. . Water glass is 3 wt% with respect to glass fiber. Then, the inner box is inserted inside, and further a gas adsorbent and a moisture adsorbent are inserted.

  The gas adsorbent used was a powder obtained by mechanically alloying Li and MgO in an Ar atmosphere. The outer box and inner box are welded at the neck portion of the inlet, the outer box is welded with a flange, sealed, and then depressurized from the exhaust port to produce a vacuum heat insulating box.

  As a result of measuring the volume of the core material produced under the same conditions as the inserted core material, and then measuring the volume after decompression, the volume reduction rate was 2.7%. The produced vacuum heat insulation box body was better than Comparative Example 1 without any noticeable change in appearance. Further, the thermal conductivity is 0.0035 W / mK, and it has higher heat insulation performance than Comparative Example 1.

  In addition, it took 30 minutes with a vacuum pump alone to reach a thermal conductivity of 0.0035 W / mK. However, with the gas adsorbent, it was evacuated with a vacuum pump for 3 minutes and then left as it was. I was able to reach the rate.

  Moreover, although it was left to stand at 40 degreeC for 3 months, the change of an external appearance and performance was not seen. Furthermore, the heat insulation performance after 6 months at 40 ° C. was measured, but no deterioration was observed.

(Embodiment 3)
FIG. 5 is a longitudinal sectional view of the vacuum heat insulation box according to the third embodiment of the present invention.

  In the longitudinal cross-sectional view of FIG. 5, the vacuum heat insulating box 15 includes an outer box 16 and an inner box 17, and a heat insulating space 7 exists between the outer box 16 and the inner box 17. A resin sheet having a metal vapor deposition film 18 is inserted inside the outer box 16 and outside the inner box 17. The inside of the heat insulation space 7 is filled with a core material 19 and has a gas adsorbent 8 and a moisture adsorber 9. The heat insulating space 7 is exhausted from the exhaust port 4 to become a decompressed space, and then the exhaust port 4 is sealed to form a sealed space.

(Example 5)
The inner box is a multilayer material made of 100 μm thick ethylene-vinyl alcohol copolymer (EVOH) having a 1.0 mm thick polypropylene and a 1 μm thick aluminum deposited film, and the molding is performed by blow molding. Polypropylene and EVOH are bonded with a bonding material (10 μm).

  The outer box is a multi-layered material consisting of 100μm thick ethylene-vinyl alcohol copolymer (EVOH) with 1mm thick high density polyethylene and 1μm thick aluminum vapor deposited film, divided into half by double injection molding. Make it. Polyethylene is mixed with a bonding material to improve adhesion with EVOH. And EVOH which has aluminum vapor deposition is installed in a metal mold | die flat part at the time of injection molding, and insert molding is carried out. EVOH joins the EVOH side with high density polyethylene. The outer box is preliminarily molded into two parts so that the inner box and the core material can be inserted and joined, and a flange is provided at the joint.

  Moreover, the coverage with the aluminum vapor deposition film was 80% of the total surface area.

And the core material solidified in the same three-dimensional shape as the space between an inner box and an outer box is inserted. The core material is prepared by press-molding glass fibers having an average fiber diameter of 5 μm at 500 ° C., adjusting the density to 250 kg / m ³ , and dividing the glass fiber into two parts. Then, the inner box is inserted inside, and further a gas adsorbent and a moisture adsorbent are inserted.

  As the gas adsorbing material, a powder obtained by compression-molding a powder obtained by mechanically alloying Li and MgO in an Ar atmosphere, and coating the periphery with calcium oxide as a moisture adsorbing material was used.

  The outer box and inner box are welded at the neck portion of the inlet, the outer box is welded with a flange, sealed, and then depressurized from the exhaust port to produce a vacuum heat insulating box.

  As a result of measuring the volume of the core material produced under the same conditions as the inserted core material, and then measuring the volume after depressurization, the volume reduction rate was 3.4%. The produced vacuum heat insulation box body was better than Comparative Example 1 without any noticeable change in appearance. Further, the thermal conductivity is 0.0030 W / mK, and it has high heat insulation performance.

  In addition, to reach a thermal conductivity of 0.0030 W / mK, 30 minutes was required only with the vacuum pump. However, with the gas adsorbent, the heat conduction was performed by simply evacuating with a vacuum pump for 3 minutes and then leaving it alone. I was able to reach the rate.

  Moreover, although it was left to stand at 40 degreeC for 3 months, the change of an external appearance and performance was not seen. Furthermore, the heat insulation performance after 6 months at 40 ° C. was measured, but no deterioration was observed.

(Embodiment 4)
FIG. 6 shows a heat storage type warming device for an automobile according to Embodiment 4 of the present invention.

  In FIG. 6, the regenerative warming device 20 is a circulation path in which the cooling water heated by the engine 22 is cooled by the radiator 23 through the cooling water circuit 21 and returned to the engine 22 again. In addition, when the cooling water at the time of starting the engine is not warmed, the thermostat 24 is fully closed, and the cooling water circulates through the bypass passage 25 without passing through the radiator 23 having a heat radiation action, and the temperature of the cooling water is increased. Speed up. Further, during continuous running of the automobile, the cooling water warmed in the cooling water circuit 21 flows from the switching inlet pipe 27 into a vacuum heat insulating container 29 called a heat storage tank, and is kept warm. Thereafter, when the engine is started, the flow control valve 26 is caused to flow out from the switching outlet pipe 28 to the cooling water circuit and mixed with the cooling water to accelerate the temperature rise of the cooling water. Therefore, it is possible to improve the fuel efficiency of the vehicle when starting the engine.

  The vacuum heat insulating box described in Example 4 was used as a heat storage tank. Thereby, the fuel consumption of the vehicle at the time of engine starting can be improved.

  In addition, the conventional thermos has a structure in which a vacuum heat insulating space is provided between the metallic inner container and the outer container, and there are restrictions on the shape in terms of strength, and a simple shape such as a cylindrical shape is common. is there. However, the vacuum heat insulation container of the present invention has a high degree of freedom in molding and can form a heat storage tank with a complicated shape, so that the vehicle space can be used efficiently, heat leak is small, heat insulation performance is excellent, and long-term reliability is achieved. And heat retention efficiency is improved.

  Moreover, it is desirable that the inner surface of the inner box of the vacuum heat insulating box used for the heat storage type warming device is a water resistant resin. By covering the inner surface of the inner box with a water-resistant resin, it is possible to prevent moisture from penetrating even when the cooling water is kept warm in the tank, and to improve durability.

  The water-resistant resin is not limited as long as it is water-resistant, but polypropylene, polyester resin, and fluorine resin are particularly excellent in water resistance and are inexpensive because they are general-purpose resins.

(Embodiment 5)
FIG. 7 is a longitudinal sectional view of a vacuum heat insulating box applied to the refrigerator in Embodiment 5 of the present invention.

  The refrigerator 30 has a vacuum heat insulating box structure, and includes an inner box 31 constituting the inside of the refrigerator and an outer box 32 constituting the outer wall, and a heat insulating layer 33 exists between the inner box 31 and the outer box 32. The outer box 32 is made of a PCM steel plate, and the inner box 31 is made of an ABS resin obtained by insert-molding an aluminum foil, and the aluminum foil is on the heat insulating layer side. The inside of the heat insulation layer 33 is filled with a core material 34 and has a gas adsorbent 35 and a moisture adsorbent 36. 37 is an exhaust port, 38 is a machine room, and 39 is a compressor. Isobutane is used as the refrigerant.

(Example 7)
The core material is made of glass fibers having an average fiber diameter of 5 μm, coated with a 3 wt% sodium silicate solution as a binder, dried in a solvent while pressing at 450 ° C. into the shape of the heat insulating layer, and solidified.

  The inner box is a multilayer material in which 3 mm thick ABS resin and 20 μm thick ethylene-vinyl alcohol copolymer (EVOH) are insert-molded with aluminum foil (10 μm). To do.

  The outer box is a 1 mm thick PCM steel plate and is formed by press molding. The core material is inserted between the outer box and the inner box, and the outer box and the inner box are joined at the contact portion.

  The heat insulating layer is depressurized from the exhaust port by a vacuum pump outside the refrigerator, and when the degree of vacuum reaches about 700 Pa, the exhaust port part is sealed, and if left standing, the degree of vacuum is reduced to about 15 Pa by the gas adsorbent. .

  Further, since the volume change rate of the core material is as small as 1%, a vacuum insulated box refrigerator having high reliability without dents and distortions is formed.

  Next, the comparative example with respect to the vacuum heat insulation box of this invention is shown.

(Comparative Example 1)
The inner box is a multilayer material made of polypropylene having a thickness of 1 mm and an ethylene-vinyl alcohol copolymer (EVOH) having a thickness of 100 μm. The polypropylene is on the inside, and molding is performed by blow molding. Polypropylene and EVOH are bonded with a bonding material (10 μm). The outer box is a multi-layer material consisting of high density polyethylene with a thickness of 1 mm and EVOH with a thickness of 100 μm. The high density polyethylene is on the outside. Like the inner box, the outer box is made by blow molding. 10 μm). The outer box formed by blow molding is cut in half, and a core material is inserted between the inner box and the outer box. As the core material, glass fibers having an average fiber diameter of 5 μm are inserted. The outer box and the inner box are welded at the neck portion of the injection port, and the outer box cut in half is welded at the cut portion, sealed, and then depressurized from the exhaust port to produce a vacuum heat insulation box.

  As a result of measuring the volume of the core material produced under the same conditions as the inserted core material, and then putting it in a laminate film and measuring the volume after decompression, the volume reduction rate was 56%. The produced vacuum heat insulation box was greatly deformed, and the thermal conductivity was 0.0125 W / mK.

  In addition, cracks occurred when left at 40 ° C. for 1 month.

(Comparative Example 2)
The inner box, outer box, and core were the same as in Example 1, and a vacuum heat insulating box was produced without using a gas adsorbent. The evacuation time of 30 minutes was required for the thermal conductivity to reach 0.0030 W / mK. In addition, the heat insulation performance after 6 months at 40 ° C. was deteriorated.

  As described above, the vacuum heat insulation box according to the present invention can reduce the load applied to the box by decompression, can constitute a vacuum heat insulation box excellent in long-term reliability and appearance, and can exhibit excellent heat insulation performance. Is. Furthermore, it is excellent in production efficiency. It can be applied to various heat insulation applications such as thermal storage equipment for automobiles, heating / cooling equipment such as refrigerators and refrigerators, and physical objects to be protected from heat and cold.

External view of the vacuum heat insulation box in Embodiment 1 of this invention The schematic diagram of the vacuum heat insulation box in Embodiment 1 of this invention The longitudinal cross-sectional view of the vacuum heat insulation box in Embodiment 1 of this invention The longitudinal cross-sectional view of the vacuum heat insulation box in Embodiment 2 of this invention The longitudinal cross-sectional view of the vacuum heat insulation box in Embodiment 3 of this invention The block diagram of the thermal storage type warming device of the motor vehicle using the vacuum heat insulation box in Embodiment 4 of this invention The longitudinal cross-sectional view of the refrigerator which applied the vacuum heat insulation box in Embodiment 5 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulation box 3 Outer box 5 Inner box 6 Core material 7 Heat insulation space 8 Gas adsorption material 9 Moisture adsorption material 10 Vacuum heat insulation box 11 Outer box 12 Inner box 13 Metal foil 14 Core material 15 Vacuum heat insulation box 16 Outer box 17 Inner box 18 Metal vapor deposition film 19 Core material 29 Vacuum insulation container 30 Refrigerator 31 Inner box 32 Outer box 33 Heat insulation layer 34 Core material 35 Gas adsorbent material 36 Moisture adsorbent material

Claims (7)

  A vacuum heat insulation box having a vacuum heat insulation structure comprising at least an outer box and an inner box made of a gas barrier material, and a core material sealed under reduced pressure in a space constituted by the outer box and the inner box, A vacuum heat insulating box having a volume change rate before and after decompression of a core material of 50% or less and a gas adsorbent capable of adsorbing at least nitrogen in the space and a portion that can be vented.   The vacuum heat insulating box according to claim 1, wherein the core material has a three-dimensional shape.   The vacuum heat insulation box according to claim 2, wherein the three-dimensional core material is divided into at least two.   The vacuum heat insulating box according to any one of claims 1 to 3, wherein the gas barrier material of the outer box or the inner box is a multilayered resin material and metal foil. .   The gas adsorbent capable of adsorbing nitrogen has at least Li and a transition metal that does not form an intermetallic compound with Li, and the enthalpy of mixing of the two metals is greater than zero. The vacuum heat insulation box as described in any one of 1-4.   The vacuum heat insulating box according to any one of claims 1 to 4, wherein the gas adsorbent capable of adsorbing nitrogen has at least Li and a solid substance having a hardness of 5 or more at 25 ° C. .   The vacuum heat insulating box according to claim 5 or 6, wherein the gas adsorbent capable of adsorbing nitrogen is manufactured by including at least a mixing step by mechanical alloying.

Images