JP5198167B2 - Vacuum insulation box - Google Patents

Description

  The present invention relates to a vacuum heat insulating box that can be used as a heat insulating material such as a refrigerator, a heat insulating cold jacket material, a vending machine, an electric water heater, a vehicle, etc.

  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.

  For example, in a heat-reserving liquid storage container incorporated in the circulation system of an automobile engine, combustion efficiency from the initial stage of engine operation can be secured by keeping warm and effective use of heated and cooled water. In addition, in a heat retaining container such as a jar pot, it contributes to energy saving by increasing the heat retaining performance. In cold storage applications such as refrigerators and vending machines, it will contribute to energy conservation by blocking heat entry and lowering the operating rate of the refrigeration system. From the above viewpoint, a high-performance heat insulating material is required.

  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, vacuum heat insulating materials have been proposed as high performance heat insulating materials.

  A vacuum heat insulating material is a heat insulating material in which a foamed resin, fiber material, inorganic powder, etc. is used as a core material and is put in a jacket material, and the heat conductivity of gas is remarkably lowered by keeping the inside of the heat insulating material in a vacuum. In order to maintain the heat insulation performance over a long period of time, it is necessary to keep the inside of the heat insulating material in a vacuum.

  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 that affects 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 Since they collide with each other and heat conduction by gas occurs, the heat conductivity increases.

  The heat insulation principle of the vacuum heat insulating material is to eliminate heat conducting air as much as possible and reduce heat conduction by gas.

  Therefore, in order to maintain the performance of the vacuum insulator for a long period of time, the initial internal pressure needs to be lower. However, it is difficult to achieve a high vacuum at an industrial level, and the degree of vacuum that can be achieved practically is up to about 13 Pa.

  On the other hand, when the type of the core material is different, the air gap distance is changed, and even when the internal pressure is the same, the number of collisions between the gases is changed and the heat conduction is different. The smaller the gap distance, the smaller the number of collisions between the gases even at the same internal pressure, and the smaller the heat conduction by the gas. That is, as the core material having a smaller air gap distance is used, even if the internal pressure increases due to some influence, the increase in thermal conductivity due to the heat conduction of the gas is less and the heat insulation performance is less decreased.

  Since the heat insulation performance of the whole vacuum heat insulating material is also due to heat conduction by a solid such as a core material, the heat insulation performance is not necessarily superior as the gap distance is generally small, but can be properly used depending on the purpose.

  The principle and configuration of the vacuum heat insulating box is the same as the vacuum heat insulating material, but in general, the vacuum heat insulating material inserts the core material into the gas permeable outer covering material and seals it by reducing the inside. The outer jacket material is brought into close contact with the shape of the core member serving as a spacer by atmospheric compression. If the shape of the core material is complicated due to unevenness or bending, it becomes difficult to insert the core material into the outer cover material. It is difficult to follow and seal under reduced pressure.

  If molding does not follow, there is no point in giving shape to the core material, wrinkles on the outer cover material, floating without adhering to the core material, local stress is easily applied to the outer cover material, and the core The portion not in close contact with the material is easily damaged by a slight external force. Therefore, a general vacuum heat insulating material has a flat plate shape.

  However, it has followability to gentle unevenness and bending, and it can be bent or deformed after it is made into a flat plate shape. Arise.

  Therefore, the jacket material is molded into the required irregularities, bends and shapes in advance, the core material is inserted into a gas-permeable low-permeability box with strength that does not cause significant deformation by atmospheric compression, and sealed under reduced pressure Is distinguished from a vacuum heat insulating material to form a vacuum heat insulating box. If it is this method, the vacuum heat insulating material (vacuum heat insulation box) which has the unevenness | corrugation and bending more complex than a vacuum heat insulating material, and a box shape can be produced.

  In addition, it is called a vacuum heat insulation box, but it is not necessarily a box shape, the jacket material has a strength that does not greatly deform due to atmospheric compression, and has a hollow double wall structure. What is necessary is just a characteristic, and a magnitude | size and a shape do not ask | require. For example, a pipe shape, a shape having irregularities on a flat plate, a bottle shape, and a spherical shape are also included.

  By increasing the degree of vacuum inside the vacuum heat insulation box, high performance heat insulation performance can be obtained, but the gas existing inside the vacuum heat insulation box is roughly divided into the following three types. One is the gas that cannot be evacuated when the vacuum heat insulation box is manufactured, and the other is the gas generated from the core material and the jacket material after being vacuum-sealed (adsorbed to the core material and the jacket material). The remaining gas is a gas that enters from the outside through the jacket material, and the other one is a reaction gas generated by the reaction of unreacted components of the core material.

  As a factor that increases the internal pressure of the vacuum heat insulation box, in the long run, when the box is made of resin material, the vacuum heat insulation box is transmitted through the box part and the thermally welded resin layer. When a gas such as air or water vapor gradually enters the body from the outside, there is a problem that the degree of vacuum decreases and the heat insulation performance deteriorates. In the case of a metallic box, there is a possibility that air components may intrude through poor welding or pinholes, and heat insulation performance may deteriorate.

  In addition, since the vacuum heat insulation box has a three-dimensional shape, it is generally difficult to completely fill the hollow double wall with a fibrous core material having low solid thermal conductivity and high heat insulation performance. Filling. In addition, when using a powdery core material whose heat insulation performance is slightly inferior to the fibrous core material, filling is possible, but it is not easy to fill the powder core material to the required density, and after filling, There is a problem that exhaust resistance is high, and it is necessary for a long time to evacuate, and sufficient decompression cannot be performed.

  As a technique for maintaining the vacuum degree of the vacuum heat insulating box, for example, there is Patent Document 1. In patent document 1, in a vacuum heat insulation box formed by filling a foam heat insulating material between an outer box and an inner box of a refrigerator or the like, an open cell rigid polyurethane foam is used for the foam heat insulating material, and a heat insulating wall is used for the outer box. A vacuum indicator and an open / close valve communicating with the inside are provided, and vacuum degassing is performed via the open / close valve.

  In the above configuration, the degree of vacuum inside can be monitored by a vacuum indicator that communicates with the inside of the heat insulation wall, so even if the degree of vacuum deteriorates due to gas that has entered from the outside or gas that has remained inside, the vacuum deaeration is performed via the open / close valve. By doing so, the initial heat insulation performance can be recovered.

Moreover, as a method of enclosing powder between the double walls of a hollow double wall box, for example, there is Patent Document 2. In Patent Document 2, fine particles are forcibly introduced and filled with air. At the same time, the inside of the container is depressurized from an inlet different from the sealing inlet so that the container is not deformed by the press-fitted air and is easily pressed. Further, the pressure reducing port is made of metal mesh or nonwoven fabric so that the powder does not leak. The sealing pressure is 2-8 kg / cm2G. In Patent Document 2, vacuum insulation box is not used, but a powder insulation method can also be applied to a vacuum insulation box, and after enclosure, if the pressure is reduced and sealed, a vacuum insulation box is obtained.
Japanese Patent Laid-Open No. 7-148752 Japanese Patent Laid-Open No. 2-269681

  However, in the conventional configuration described in Patent Document 1, in the vacuum heat insulating box, the gas entering from the outside and the gas generated from the inside are reduced again through the valve, but the inside of the box is reduced from the opening / closing valve. For this purpose, the exhaust resistance is large and it takes a very long time to reduce the pressure.

  Further, in Patent Document 1, open-celled rigid polyurethane foam is used as a core material. However, in open-celled rigid polyurethane foam, a large amount of gas is generated from the core material itself as the core material, and there is an air gap distance as the powder. Because of its large size, it is relatively inferior in heat insulation performance compared to a fibrous core, etc., and furthermore, if it is a powder such as silica powder having a finer particle size with a small gap distance, The exhaust resistance is further increased, and the pressure cannot be easily reduced, and a considerable time is required for the pressure reduction process.

  In addition, the technology of making rigid polyurethane foam into open cells is difficult, and when urethane resin is foamed in a container, a skin layer is generated on the wall surface, so the bubble communication rate inevitably decreases and the cell rate increases ( Usually, it is difficult to increase the degree of vacuum. A method of encapsulating the urethane resin powder is also conceivable, but the encapsulation process in the box becomes difficult.

  Further, in the above-described conventional configuration described in Patent Document 2, a fine powder having a small air gap distance and a small mean free path and a relatively excellent heat insulation performance has a large exhaust resistance even when pressed together with air, so that the exhaust resistance is large. The air does not escape easily, and it takes a long time to fill with a density sufficient to withstand atmospheric compression by decompression, and the container may be deformed. Further, even if the remaining air is deaerated, there is a problem that exhaust resistance is large and time is required.

  An object of the present invention is to solve the above-mentioned conventional problems, and to provide a vacuum heat insulating box having high performance and long-term reliability, further improving productivity, and excellent in dimensional stability.

  In order to achieve the above object, the vacuum heat insulating box of the present invention has a core made of a gas permeable material covering material in a space formed by an outer box and an inner box each made of a gas permeable material. It has a vacuum double wall structure having a vacuum heat insulating material formed by sealing the material under reduced pressure and a urethane foam resin, and the space being sealed under reduced pressure.

  The reason why air or water vapor enters the space between the inner box and the outer box of the vacuum heat insulation box of the present invention and the internal pressure of the space rises is a pressure difference due to atmospheric pressure between the outside air and the space. Therefore, when the vacuum heat insulation box is made of a resin material, it passes through the box part and the thermally welded resin layer, and in the case of a metallic box, it is very slowly due to poor welding or pinholes. Air component enters. In addition, air, water, unreacted material, and the like adsorbed on the material such as the box and the core material are volatilized by depressurizing, and the internal pressure is increased.

  On the other hand, the vacuum heat insulating material installed in the space passes from the heat-welded layer if it is sealed with a laminate film, from the resin layer if it is welded with resin, from a poor weld or pinhole if metal material is welded, Air, water vapor, etc. enter the vacuum insulation.

  However, by reducing the pressure in the space, the pressure difference with the vacuum heat insulating material is reduced, the gas penetration rate into the vacuum heat insulating material is reduced, and the long-term reliability of the vacuum heat insulating material can be improved. The long-term reliability of the box can be increased.

  Furthermore, since the vacuum heat insulating material itself has high heat insulating performance, the heat insulating performance of the vacuum heat insulating box is also increased.

  Moreover, although a vacuum heat insulating material is scarce in atypical property, it can be installed in the plane part of a box, and can also be installed in some curved parts and bending places. By foaming the foamed urethane resin in the space where the vacuum heat insulating material is not installed, it is possible to fill every corner of the box, and heat insulation of the box can be ensured.

  In addition, since the foamed urethane resin is usually not connected but has a closed cell rate of about 5 to 15%, even if the pressure is reduced, it is difficult to reach a vacuum degree of 13 Pa like a vacuum heat insulating material. Since the gas component flows out from the air and the internal pressure gradually increases slightly, it is difficult to obtain the heat insulation performance equivalent to the vacuum heat insulating material, but the pressure value is very small compared to the outside air. Therefore, the amount of outside air entering the vacuum heat insulating material becomes very small, and the long-term reliability of the vacuum heat insulating box can be ensured.

  In addition, the foamed urethane resin can be filled by injecting the raw material mixture, and the procedure of press-fitting powder is unnecessary, and the process can be shortened.

  Moreover, the urethane foam resin itself is an excellent heat insulating material, and it becomes a further excellent heat insulating material by compounding.

  Moreover, since the vacuum heat insulating material exists in the space, the vacuum heat insulating material is already compressed by the atmospheric pressure, so even if the space inside the vacuum heat insulating box is depressurized, It is effective as a spacer and becomes a vacuum heat insulating box body with excellent dimensional stability. In addition, vacuum heat insulating material is placed on the flat surface due to its characteristics, but the flattened portion is the most deformable part in atmospheric compression by decompression, which contributes to both heat insulation performance improvement and dimensional stability improvement. It is possible.

  The vacuum insulation material, which has high performance but its heat insulation performance decreases with increasing internal pressure, and is difficult to apply to a deformed body, is used in combination with urethane foam resin in the hollow double wall space of the vacuum heat insulation box. By reducing the pressure of the wall space, the vacuum insulation box with high performance, high reliability, high dimensional stability, and improved productivity is realized by taking advantage of both the vacuum insulation material and urethane foam resin. Can be provided.

The invention of the vacuum heat insulation box according to claim 1 of the present invention has a urethane resin inside a space formed by an outer box and an inner box made of a gas-impermeable material, and the space is sealed under reduced pressure. A vacuum heat insulating box, wherein the vacuum heat insulating box is formed by vacuum-sealing a core material inside the space of the vacuum heat insulating box that is sealed under reduced pressure, and further inside a jacket material of a gas permeable material. By providing, it has a vacuum double wall structure.

  The reason why air or water vapor enters the space between the inner box and the outer box of the vacuum heat insulation box of the present invention and the internal pressure of the space rises is a pressure difference due to atmospheric pressure between the outside air and the space. Therefore, when the vacuum heat insulation box is made of a resin material, it passes through the box part and the thermally welded resin layer, and in the case of a metallic box, it is very slowly due to poor welding or pinholes. Air component enters. In addition, air, water, unreacted material, and the like adsorbed on the material such as the box and the core material are volatilized by depressurizing, and the internal pressure is increased.

  On the other hand, the vacuum heat insulating material installed in the space passes from the heat-welded layer if it is sealed with a laminate film, from the resin layer if it is welded with resin, from a poor weld or pinhole if metal material is welded, Air, water vapor, etc. enter the vacuum insulation.

  However, by reducing the pressure in the space, the pressure difference with the vacuum heat insulating material is reduced, the gas penetration rate into the vacuum heat insulating material is reduced, and the long-term reliability of the vacuum heat insulating material can be improved. The long-term reliability of the box can be increased.

  Furthermore, since the vacuum heat insulating material itself has high heat insulating performance, the heat insulating performance of the vacuum heat insulating box is also increased.

  Moreover, although a vacuum heat insulating material is scarce in atypical property, it can be installed in the plane part of a box, and can also be installed in some curved parts and bending places. By foaming the foamed urethane resin in the space where the vacuum heat insulating material is not installed, it is possible to fill every corner of the box, and heat insulation of the box can be ensured.

  In addition, since the foamed urethane resin is usually not connected but has a closed cell rate of about 5 to 15%, even if the pressure is reduced, it is difficult to reach a vacuum degree of 13 Pa like a vacuum heat insulating material. Since the gas component flows out from the air and the internal pressure gradually increases slightly, it is difficult to obtain the heat insulation performance equivalent to the vacuum heat insulating material, but the pressure value is very small compared to the outside air. Therefore, the amount of outside air entering the vacuum heat insulating material becomes very small, and the long-term reliability of the vacuum heat insulating box can be ensured.

  In addition, the foamed urethane resin can be filled by injecting the raw material mixture, and the procedure of press-fitting powder is unnecessary, and the process can be shortened.

  Moreover, the urethane foam resin itself is an excellent heat insulating material, and it becomes a further excellent heat insulating material by compounding.

  Moreover, since the vacuum heat insulating material exists in the space, the vacuum heat insulating material is already compressed by the atmospheric pressure, so even if the space inside the vacuum heat insulating box is depressurized, It is effective as a spacer and becomes a vacuum heat insulating box body with excellent dimensional stability. In addition, vacuum heat insulating material is placed on the flat surface due to its characteristics, but the flattened portion is the most deformable part in atmospheric compression by decompression, which contributes to both heat insulation performance improvement and dimensional stability improvement. It is possible.

  The gas permeable material preferably has a gas permeability of 104 [cm 3 · 20 μm / m 2 · day · atm] or less, more preferably 1 [cm 3 · 20 μm / m 2 · day · atm] or less. It will be.

  Further, the gas-impermeable material of the vacuum heat insulation box includes metal materials such as stainless steel and iron, glass materials, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon, polyvinyl alcohol, crystals A gas-impermeable resin such as crystalline polyethylene terephthalate and crystalline syndiotactic polystyrene is preferred.

  Further, by forming a film made of metal, SiO2, Al2O3, and diamond-like carbon on the resin material, it is possible to impart further gas permeability and improve reliability.

  In addition, the resin material can be improved in reliability by insert molding a metal foil laminate film such as an AL foil laminate film or an AL vapor deposition laminate film.

  Furthermore, it is preferable to use a laminate film obtained by laminating a metal foil such as aluminum on a resin film as the gas permeable material of the vacuum heat insulating material. Metal foil has very high gas permeability and high reliability. Moreover, the barrier property which was excellent also in the vapor deposition layer instead of foil is produced.

  Further, even when vapor deposition of an inorganic material such as SiO 2, Al 2 O 3, and diamond-like carbon is used instead of metal, it has high gas permeability. Also, as with the gas-impermeable material of vacuum insulation box, metal materials such as stainless steel and iron, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon, polyvinyl alcohol, crystalline polyethylene terephthalate Alternatively, a gas permeable resin such as crystalline syndiotactic polystyrene may be used. Further, by forming a film made of metal, SiO2, Al2O3, and diamond-like carbon on the resin material, it is possible to impart further gas permeability and improve reliability.

  In addition, when a laminate film is used as a gas-impermeable material for vacuum insulation, if polyethylene is used for the heat-welded layer, polyethylene can be welded at a relatively low temperature, making it easier to weld by additional heating and lower cost. A vacuum insulation box can be provided.

  In addition, when the outermost layer of the laminate film has a protective layer, by providing a material for surface protection in the outermost layer, more reliable scratch resistance and piercing resistance can be exhibited, and pinholes and the like can be exhibited. The vacuum heat insulating material which has the effect | action which suppresses generation | occurrence | production and has long-term reliability can be provided. Among them, polyethylene terephthalate is an inexpensive material, and the vacuum heat insulating box of the present invention can be provided at a lower cost.

  Moreover, although it does not limit as a core material of a vacuum heat insulating material, a fibrous core material and a powder core material are preferable. The fiber core material has excellent heat insulation performance as its feature, and the powder core material has slightly lower heat insulation performance than the fiber core material, but the decrease rate of the heat insulation performance with respect to pressure increase is small, and long-term reliability is excellent.

  Although the fiber core material is not limited, glass fiber, glass fiber, alumina fiber, silica alumina fiber, silica fiber, rock wool, silicon carbide fiber, etc. are preferable. Especially, glass fiber is inexpensive and high performance vacuum heat insulating material. Most desirable for forming. The glass fiber is preferably in the range of 1 μm to 20 μm, more preferably 2 μm to 10 μm with rigidity as a core material, and more preferable in terms of productivity and thermal conductivity.

  Further, although the powder core material is not limited, the inorganic powder material is preferable because it originally retains the powder and generates less gas (outgas) from the powder during decompression.

  Furthermore, the powder core material is preferably dry silica having an average primary particle diameter of 100 nm or less. As the core material, the powder material in which the air gap distance is shorter is more excellent in pressure dependency, and therefore is superior to the fiber material in order to obtain long-term reliability. In addition, the solid thermal conductivity is low, and a silica-based material is excellent as a core material for a vacuum heat insulating material as a powder core material. Moreover, since the average primary particle diameter is 100 nm or less, the particle size is excellent in that the heat insulation performance with respect to the internal pressure is small, and such silica powder corresponds to dry silica produced by a dry method.

  Moreover, heat insulation performance improves rather than the vacuum heat insulating material which used only dry silica powder by mixing 1-30 wt% of carbon black with dry silica.

  As powders added to dry silica to improve heat insulation performance, for example, carbon black and titanium oxide are known to work as radiation prevention materials at high temperatures, but the addition of carbon black greatly improves heat insulation performance at low temperatures. It can be seen. Although this reason is not certain, it is considered that solid heat conduction is reduced by some action of silica powder and carbon black.

  The addition amount of the powdery carbon material is preferably 1 to 30 wt%. This is because if the addition amount is too small, there is no effect of improving the heat insulation performance, and if it is too large, the heat insulation performance becomes dependent on the powdered carbon material and the heat insulation performance deteriorates, or gas generation increases under reduced pressure. This is because the heat insulation performance deteriorates.

  Further, as a composite of a fibrous core material and a powder core material, a glass fiber material is mixed in the dry silica, the glass fiber material has an average fiber diameter of 10 μm or less, and the content in the core material is 0. It is 5-40 wt%, and what was shape | molded by pressing is preferable.

  Although dry silica has excellent performance as a core material for a vacuum heat insulating material, it is difficult to handle because of its low density, and it is necessary to seal it once in a nonwoven fabric for filling, which increases costs and the number of processes. Therefore, solidifying and encapsulating dry silica is excellent in the process.

  As a solidification means, a general silica powder and a fiber material are mixed and stirred, and even if pressure-molded, it does not become a molded body. However, dry silica having an average primary particle size of 100 nm or less and a fiber material are mixed and added. A compact can be formed by pressure molding. This may be due to the fact that powders with small particle diameters cause intermolecular forces to act and the powders adhere to each other, or because they are dry, the surface functional groups are few and the mutual repulsion is so small that the powders are likely to adhere to each other. Therefore, in order to produce a molded body by a molding method such as pressurization, it is necessary to use dry silica having an average primary particle diameter of 100 nm or less and a fiber material.

  Further, by making the glass fiber material have an average fiber diameter of 10 μm or less, the specific surface area is increased because the fiber diameter of the glass fiber is small, that is, the surface energy is increased, and the glass powder is easily combined with the powder. Since it is a combination with good affinity, it is considered that it is easy to adhere to each other or due to their interaction. Therefore, when producing a molded body by a molding method such as pressure, a glass having an average fiber diameter of 10 μm or less By using a fiber material, a stronger molded body can be produced.

  Further, by using dry silica having a very fine particle diameter and a glass fiber material having a small fiber diameter, a molded body having almost no dusting can be obtained. This is because, as described above, the intermolecular force between powders having a small particle diameter, adhesion between powders due to a small number of surface functional groups, good affinity between silica and glass fibers, large surface energy of thin fiber materials, etc. Can be considered.

  In addition, a strong molded body can be obtained by the above combination, and a molded body having flexibility can be obtained because it has elasticity.

  The reason for this is considered to be that, since fibers having an average fiber diameter of 10 μm or less are used, flexural elasticity is improved and flexibility can be obtained.

  The fiber addition amount is 0.5 to 40 wt% because if the addition amount is too small, the shape of the molded body cannot be maintained, and if it is too much, the heat insulation performance becomes dependent on the fiber and the heat insulation performance is deteriorated. .

  Further, the jacket material of the vacuum heat insulating material has a heat welding layer, the heat sealing layer is heat welded, and the vacuum heat insulating material is sealed, and the heat welding layer is formed along the core material. It is preferable that heat welding is performed up to the core material.

  When the heat-welded layer is heat-welded along the core material to the core material, the sealing performance is improved, and the portion without the core material (fin portion) between the jacket materials is cut to the core material. The area occupied by the vacuum heat insulating material can be improved, and the performance of the vacuum heat insulating box can be improved.

  The invention of a vacuum heat insulation box according to claim 2 is the invention according to claim 1, wherein the core material of the vacuum heat insulation material is a fibrous core material having orientation, and the transmission of the vacuum heat insulation box body. The vacuum heat insulating material is arranged so that the orientation direction of the fibrous core material is substantially perpendicular to the heat direction.

  The fibrous core material is oriented in a direction perpendicular to the pressurizing direction when the fiber oriented in a random direction is pressed in one direction. Usually, in order to adjust the density, a molded body is formed by adding a binder or pressurizing while heating. Since the fibrous core material undergoes solid heat conduction in the fiber direction, the solid heat conduction is likely to be transmitted in a direction parallel to the orientation direction by pressurization or the like. On the other hand, in the direction perpendicular to the orientation direction, the fibers are in point contact and the solid heat conduction is greatly reduced. Therefore, the heat insulation performance is higher in the direction perpendicular to the orientation direction. Therefore, effective heat insulation performance can be expressed by installing the vacuum heat insulating material in a direction substantially perpendicular to the orientation direction of the fibrous core material with respect to the heat transfer direction of the vacuum heat insulating box.

  Actually, making the orientation direction of the fibrous core material completely perpendicular to the heat transfer direction of the vacuum heat insulation box means that the heat transfer direction is not uniform and the fibrous core material is perfectly oriented. Since it is difficult because it is not, for example, the direction is substantially vertical, and the substantially vertical direction may be within an angle of 70 to 110 degrees with respect to the main heat transfer direction.

  The invention of a vacuum heat insulation box according to claim 3 is the invention according to claim 1 or claim 2, further comprising a gas adsorbing material for adsorbing the gas in the vacuum heat insulating material in the vacuum heat insulating material. It is characterized by this.

  By providing a gas adsorbent for adsorbing the gas in the vacuum heat insulating material in the vacuum heat insulating material, the vacuum heat insulating material absorbs the gas entering from the heat-welded layer from the foamed urethane resin with a slight internal pressure difference. The heat insulation performance can be maintained, and long-term reliability can be further enhanced.

  Furthermore, even if the vacuum insulation box is broken for some reason, the vacuum insulation remains high performance, but the amount of air intrusion from the heat-welded layer increases and the pressure difference increases. Therefore, the reliability is lowered. However, by installing the gas adsorbing material in contact with the fibrous core material in the vacuum heat insulating material, it is possible to suppress an increase in internal pressure and maintain the reliability of the heat insulating performance.

  The gas adsorbent is not particularly limited, and the adsorption mechanism may be any of physical adsorption, chemical adsorption, occlusion, and sorption, but a substance that acts as a non-evaporable getter is good.

  Specifically, it is a physical adsorbent such as synthetic zeolite, activated carbon, activated alumina, silica gel, dosonite, hydrotalcite.

  As the chemical adsorbent, oxides of alkali metals and alkaline earth metals, hydroxides of alkali metals and alkaline earth metals, etc. can be used. In particular, lithium oxide, lithium hydroxide, calcium oxide, calcium hydroxide, Magnesium oxide, magnesium hydroxide, barium oxide, and barium hydroxide are effective.

  In addition, calcium sulfate, magnesium sulfate, sodium sulfate, sodium carbonate, potassium carbonate, calcium chloride, lithium carbonate, unsaturated fatty acid, iron compound and the like also act effectively.

  In addition, it is more effective to apply a getter material obtained by singly or alloying materials such as barium, magnesium, calcium, strontium, titanium, zirconium, vanadium, and lithium.

  Furthermore, in order to adsorb and remove at least nitrogen, oxygen, moisture, and carbon dioxide, the getter material can be applied in various mixtures.

  ZSM-5 type zeolite in which the gas adsorbent is subjected to copper ion exchange is most preferable as the air adsorbent. Copper ion exchanged ZSM-5 type zeolite has higher air adsorption per unit weight at room temperature than other zeolites and metal adsorbents, and can absorb a large amount of air in a small amount. Space can be made.

  The invention of a vacuum heat insulation box according to claim 4 is the invention according to any one of claims 1 to 3, wherein a gas adsorbent for adsorbing a gas in the space in the space is provided. It is characterized by comprising.

  By providing a gas adsorbing material for adsorbing the gas in the space in the space, an increase in internal pressure due to the gas volatilized from the single foam of the urethane foam resin is suppressed, and gas entering the vacuum heat insulating material is also suppressed. High performance can be maintained, and the reliability of the entire vacuum heat insulation box can be maintained.

  The gas adsorbing material installed in the urethane foam resin is not particularly limited, and any gas adsorbing material that can be applied to the invention according to claim 3 may be used.

  However, in the case of urethane foam resin, it is preferable to change the main gas adsorbent depending on the foaming conditions. For example, when water is used as the foaming agent, a moisture adsorbent is used as the main gas adsorbent.

  When supercritical carbon dioxide or supercritical nitrogen is used as the foaming means, a carbon dioxide adsorbent and a nitrogen adsorbent may be used as the main gas adsorbent, respectively.

  Moreover, it is good to use a hydrocarbon adsorbent etc. for an unfoamed component.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the same components as those of the above-described embodiments will be denoted by the same reference numerals, and detailed description thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
1 is a cross-sectional view of a vacuum heat insulating box in Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of a vacuum heat insulating material installed in the space of the vacuum heat insulating box in Embodiment 1 of the present invention. .

  In FIG. 1, a vacuum heat insulation box 1 having a vacuum double-wall structure is formed by an outer box 2 and an inner box 3 made of a gas permeable material, and an outer box 2 and an inner box 3, respectively, and sealed under reduced pressure. The space 6 includes a vacuum heat insulating material 4, a foamed urethane resin 5, and a gas adsorbing material 7 for a vacuum heat insulating box.

  First, in the space 6 formed by the outer box 2 and the inner box 3, the vacuum heat insulating material 4, the foamed urethane resin 5, and the gas adsorbing material 7 for the vacuum heat insulating box are installed, and the outer box 2 and the inner box 3 are joined. By sealing the space 6, the air in the space 6 is exhausted from the exhaust port 8 provided in the outer box 2 and communicating the space 6 and the external space, and after decompression, the exhaust port 8 is sealed, The vacuum heat insulation box 1 is comprised. The inner box 3 has an opening 9 for taking in and out hot water and cold water. Moreover, the vacuum heat insulating material 4 equips the inside with the gas adsorbent 10 for vacuum heat insulating materials.

  In FIG. 2, a vacuum heat insulating material 4 is an outer cover material 11 made of two gas-impermeable materials, and includes a fibrous core material 12 formed by press-molding short glass fibers and a gas adsorbing material 10 for vacuum heat insulating material. Covering, installing the gas adsorbent 10 for vacuum heat insulating material so as to contact the fibrous core material 12, and reducing the pressure inside, and heat-welding the opposing heat-welded layer 12 of the jacket material 11 to maintain the vacuum Yes.

  The fibrous core material 12 of the vacuum heat insulating material 4 has orientation, and the vacuum heat insulating material 4 is arranged so that the orientation direction of the fibrous core material 12 is substantially perpendicular to the heat transfer direction of the vacuum heat insulating box 1. It is.

  Next, the manufacturing method of the vacuum heat insulation box 1 is demonstrated. The inner box 2 and the outer box 3 were formed by injection molding using crystalline syndiotactic polystyrene. The inner box 2 and the outer box 3 are injection-molded using molds that differ only in the upper surface, with the direction in which the opening 9 is located at the top. The opening 9 is formed on the upper surface of the inner box 2 by injection molding. After molding, each part is subjected to electroless plating to improve gas permeability. The electroless plating is Cu 3 μm / Ni 5 μm, and the welded portion is prevented from being plated with a masking tape.

  Next, the upper surface portion of the inner box 2 and the main body are heat-welded to form the inner box 2. Next, the vacuum heat insulating material 4 is bonded to the surface of the inner box 2 with an epoxy resin. At this time, since heat insulation such as hot water or a cold insulation material such as ice water enters the space connected by the opening 9 of the inner box 2, the inner box 2 is regarded as a heat source, and the orientation of the fibrous core material 12 is Affix it so that it is almost perpendicular to the heat transfer direction from the heat source.

  Next, the inner box 2 to which the vacuum heat insulating material 4 is attached is installed in the main body of the outer box 3, and simultaneously, the gas adsorbing material 7 for the vacuum heat insulating box body is also installed in the gap portion. As the gas adsorbent 7 for vacuum heat insulating box, a composite of calcium oxide that adsorbs moisture and ZSM-5 type zeolite substituted with Cu that adsorbs oxygen and nitrogen was used.

  Calcium oxide is put into a non-woven fabric for easy handling, Cu-substituted ZSM-5 type zeolite is sealed, and it is inactivated by adsorbing ambient air components during installation by making it a device that softens and opens by heating. To prevent you from doing. And the upper surface part of the outer case 3 is match | combined and heat welding is carried out. The welded portion is the outer periphery and the peripheral portion of the exhaust port 8 and the opening 9.

  And the liquid which mixed the polyol which is the raw material of the foaming urethane resin 5, isocyanate, and a foaming agent (cyclopentane) from the exhaust port 8 is inject | poured. Since the liquid is injected and foamed, the foamed urethane resin 5 spreads through the space 6 to every corner. At this time, the exhaust port 8 is sealed so that only the gas escapes, so that the urethane foam resin 5 does not overflow from the exhaust port 8. Further, the inner box 2 and the outer box 3 have a strength that does not deform due to foaming pressure, or are fixed with a jig as necessary, or are subjected to air pressure or water pressure to prevent deformation.

  After the core material is sealed, the space 6 is decompressed from the exhaust port 8, and the exhaust port 8 is pinched and sealed while the pressure is reduced, thereby completing the vacuum heat insulation box 1. After completion, by heating the vacuum heat insulation box 1 at 100 ° C., the gas adsorbent 7 for vacuum heat insulation box is opened, and air component adsorption ability is expressed.

  Next, the manufacturing method of the vacuum heat insulating material 4 is demonstrated. Glass fiber is used for the fibrous core material 12, and a glass fiber assembly having an average fiber diameter of 3.5 μm is heated in a pressurized state, and a board-like one having a density of about 200 kg / m 3 is maintained. Use. The average fiber diameter is evaluated based on an average value obtained by measuring N = 50 with a microscope. The average fiber diameter is preferably in the range of 1 μm to 20 μm, and 2 μm to 10 μm has rigidity as a core material, and productivity and heat More preferable in terms of conductivity.

  Then, after drying the fibrous core material 12 in a drying furnace at 140 ° C. for 30 minutes, the three sides of the laminate film are sealed with the heat-welding layer 13 by heat-welding and formed into a bag shape, and moisture is adsorbed on the jacket material 11. Insert the gas adsorbent 10 for vacuum heat insulating material, which is a composite of calcium oxide sealed in a nonwoven fabric that is a material, and a ZSM-5 type zeolite that is vacuum-sealed with a Cu-substituted ZSM-5 type zeolite in a laminate film that is an oxygen / nitrogen adsorbent, In the decompression chamber, the pressure is reduced so that the inside of the jacket material 11 becomes 10 Pa or less, and the opening is hermetically sealed by thermally welding the heat welding layer 13. At this time, when hermetically sealed, the vacuum heat insulating material 4 is compressed to the atmosphere, and using the force of the atmospheric compression, the laminate film containing the oxygen / nitrogen adsorbent is pierced with a needle-shaped material and opened. The gas adsorbing ability is manifested after sealing and sealing.

  At this time, the covering material 11 is a polyethylene terephthalate film (12 μm) as a surface protective layer, an aluminum foil (6 μm) having poor gas permeability as an intermediate layer, and a linear low density polyethylene film (50 μm) as a heat welding layer 13. ). After sealing, the density of the fibrous core material 12 slightly increases due to atmospheric compression.

  The density of the fibrous core material 12 made of glass fiber after sealing in terms of heat insulation performance and handleability is more preferably in the range of 210 to 280 kg / m 3, and the density is 240 kg / m 3. Here, the core material is formed without using the binder, but the core material may be formed at a lower temperature using the binder.

  If the surface property does not matter, the glass fiber aggregate may be hermetically sealed as it is. In that case, since the number of manufacturing steps is reduced, productivity is improved.

  The thermal conductivity of the vacuum heat insulating material 4 thus formed was measured with an auto lambda manufactured by Eihiro Seiki. As a result, the thermal conductivity was 0.0011 to 0.0017 W / mK at an average temperature of 24 ° C., and had a heat insulation performance 10 times or more that of a general-purpose hard urethane foam.

  When hot water of 95 ° C. is poured from the opening 9 of the vacuum heat insulating box 1 produced as described above, and the opening 9 is closed and left for 12 hours, the hot water temperature is 78 ° C. and has good heat retention characteristics. Moreover, even if the same evaluation was repeated 30 times, no difference was observed in the heat retention characteristics.

  Next, a mechanism for increasing the internal pressure of the vacuum heat insulating box 1 will be described.

  Air or water vapor from outside air enters the vacuum heat insulating box 1 through the material of the outer box 2 or the inner box 3 or the welding / welding location. Moreover, it is contained in the air component adsorbed to the constituent material of the outer box 2, the inner box 3, and the vacuum heat insulating material 4 originally present in the space 6, the unreacted component of the foamed urethane resin 5, the foaming agent, and the raw material. There are initial residual components such as air components and moisture. The initial residual component is removed to some extent by the reduced pressure, but the gas component in the closed cell of the foamed urethane resin 5 cannot be completely removed by the reduced pressure in a short time. Then, air and water vapor existing in the space 6 enter the vacuum heat insulating material 4 through the heat welding layer 13. Here, factors affecting the amount of air and water vapor intrusion affect the pressure difference between the outside and inside, the length and area of the heat-welded layer connecting the outside and inside, the type of gas, temperature, humidity, etc. If the manufacturing process is the same, the influence by the pressure difference between the outside and the inside is great.

  The pressure difference between the space 6 in the vacuum heat insulating box 1 and the outside air is close to 1 atm including the influence of the remaining components, and the air component is in the space 6 according to the gas permeability of the outer box 2 and the inner box 3. However, the amount is very small and increases or decreases depending on conditions such as space volume, gas permeability, temperature, initial residual amount, closed cell rate, etc. The internal pressure of the vacuum heat insulating material 4 is low, the air pressure that penetrates into the vacuum heat insulating material 4 through the thermal welding layer 13 is further minute, and the heat insulating performance of the vacuum heat insulating material 4 is Almost no degradation and long-term reliability.

  The ratio of the vacuum heat insulating material 4 and the urethane foam resin 5 in the vacuum heat insulating box 1 is not particularly limited, but the heat insulating performance is improved when the ratio of the vacuum heat insulating material 4 is larger.

  Further, in order to fill the urethane foam resin 5 to every corner, it is necessary to communicate with the places where the urethane foam resin 5 is filled.

  In addition, the vacuum heat insulating box 1 normally compresses the outer box 2 and the inner box 3 by the atmospheric pressure by decompressing the space 6 from the exhaust port 8. If the outer box 2 and the inner box 3 do not have enough strength to withstand atmospheric pressure, or if the space 6 does not have a core material having compressive strength that can withstand atmospheric pressure, the outer box 2 or the inner box 3 is deformed. Although depending on the degree of deformation, the heat insulation performance may be reduced or cracks may occur due to a decrease in the thickness of the heat insulation layer, and the outside air may enter the space 6. However, the vacuum heat insulating material 4 is compressed to the atmosphere from the beginning, and even if the space 6 is depressurized, the vacuum heat insulating material 4 is not deformed from the initial thickness, and the vacuum heat insulating material 4 is installed in the space 6 as a spacer. Also effective. When a metal or resin is used as a spacer, it causes heat leak, but the vacuum heat insulating material 4 has excellent heat insulating performance, and there is no problem of heat leak.

  Further, it is preferable that the vacuum heat insulating material 4 has the same thickness as the space 6 because the deformation is small and the heat insulating performance is excellent.

  In practice, the orientation direction of the fibrous core material 12 is completely perpendicular to the heat transfer direction of the vacuum heat insulation box 1 because the heat transfer direction is not uniform and the fibrous core material 12 is completely Therefore, the vertical direction may be within a range of 70 to 110 degrees with respect to the main heat transfer direction.

  Moreover, since the vacuum heat insulating material 4 is inserted into the space 6 of the vacuum heat insulating box 1 as a core material, the amount of the urethane foam resin 5 enclosed is less than that enclosed in the entire space. Less time is required and productivity can be improved.

  In addition, it is desirable that the moisture adsorbing material be provided with the ability to suppress an increase in internal pressure by removing moisture adsorbed on each constituent material and further by adsorbing water vapor entering from outside air. Moreover, since an installation place exhibits the most effect by installing so that it may touch each of the vacuum heat insulating material 4 and the urethane foam resin 5, it is preferable. If a moisture adsorbent is installed only on the fibrous core material 12, even if water vapor enters the space 6 for some reason, such as the outer box 2 or the inner box 3 being damaged, a vacuum heat insulating material is passed through the heat-welded layer 13. Since the water vapor entering the inside 4 is adsorbed, the heat insulating performance of the vacuum heat insulating material 4 can be maintained, and the reliability can be maintained. Moreover, if a water | moisture-content adsorption material is installed so that it may contact | connect only the foaming urethane resin 5, the internal pressure rise in the space 6 can be suppressed by adsorb | sucking the water vapor which penetrates in the space 6, and reliability can be maintained.

  Although the type of moisture adsorbent is not particularly limited, specifically, as the physical adsorbent, synthetic zeolite, activated carbon, activated alumina, silica gel, dosonite, hydrotalcite, metal complex, etc. are desirable, As adsorbents, oxides of alkali metals and alkaline earth metals, hydroxides of alkali metals and alkaline earth metals, etc. can be used, and in particular, lithium oxide, lithium hydroxide, calcium oxide, calcium hydroxide, oxidation Magnesium, magnesium hydroxide, barium oxide and barium hydroxide are effective. Calcium chloride and phosphorus pentoxide are also effective.

  In addition, the oxygen / nitrogen air component adsorbent can suppress the increase in internal pressure by adsorbing the air component remaining without being fully depressurized and the air component entering from the outside air. Improves.

  Moreover, since the installation place of an air component adsorption material touches each of the vacuum heat insulating material 4 and the foaming urethane resin 5 and exhibits the most effect, it is preferable. If an air component adsorbent is installed only on the fibrous core material 12, even if an air component enters the space 6 due to some reason, such as the outer box 2 or the inner box 3 being damaged, a vacuum is passed through the heat-welded layer 13. Since the air component which penetrates into the heat insulating material 4 is adsorbed, the heat insulating performance of the vacuum heat insulating material 4 can be maintained, and the reliability can be maintained. In addition, when the air component adsorbing material is installed so as to be in contact with only the urethane foam resin 5, it is possible to suppress the increase in internal pressure in the space 6 by adsorbing the air component entering the space 6 and maintain reliability. .

  Moreover, as an air component adsorbent, the adsorption mechanism may be any of physical adsorption, chemical adsorption, occlusion, and sorption, but a substance that acts as a non-evaporable getter is good.

  Specifically, it is a physical adsorbent such as synthetic zeolite, activated carbon, activated alumina, silica gel, dosonite, hydrotalcite.

  As the chemical adsorbent, oxides of alkali metals and alkaline earth metals, hydroxides of alkali metals and alkaline earth metals, etc. can be used. In particular, lithium oxide, lithium hydroxide, calcium oxide, calcium hydroxide, Magnesium oxide, magnesium hydroxide, barium oxide, and barium hydroxide are effective.

  In addition, calcium sulfate, magnesium sulfate, sodium sulfate, sodium carbonate, potassium carbonate, calcium chloride, lithium carbonate, unsaturated fatty acid, iron compound and the like also act effectively.

  Moreover, if it is for adsorbing carbon dioxide, an alkaline compound such as sodium hydroxide or potassium hydroxide is preferred.

  In addition, it is more effective to apply a getter material obtained by singly or alloying materials such as barium, magnesium, calcium, strontium, titanium, zirconium, vanadium, and lithium.

  Furthermore, in order to adsorb and remove at least nitrogen, oxygen, moisture, and carbon dioxide, the getter material can be applied in various mixtures.

  However, ZSM-5 type zeolite with exchanged copper ions has a higher gas adsorption amount per unit weight at room temperature than other zeolites and metal adsorbents, and adsorbs a large amount of air with a small amount of gas adsorbents. Even a low vacuum of about 10 Pa, which exhibits heat insulation performance as a vacuum heat insulating material, exhibits its adsorption ability, and also adsorbs nitrogen that is difficult to adsorb with nonpolar molecules having a large binding energy of about 940 kJ / mol. This is the most preferable gas adsorbent 7 because it is possible, has high performance and is effective, and can save space.

  In addition, air component adsorbents include not only air components but also materials that adsorb water vapor. Preferably, air component adsorbents are structured to wrap air component adsorbents in moisture adsorbents, or pass through moisture adsorbents. It is more preferable to adopt a structure in which the air component and water vapor reach, because the adsorption capacity of the air component adsorbent can be maintained for a long time.

  As the covering material 11, an AL foil laminated film and an AL vapor-deposited laminated film are preferable because they have excellent gas permeability, and even if a metal foil other than AL is used, the effect does not change. Further, a film material on which an inorganic material such as silica, diamond-like carbon, or alumina is deposited and coated may be used.

Moreover, although the gas permeability is inferior to that of metal foil or inorganic material coating, it may be a gas permeability resin such as ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon, polyvinyl alcohol, More preferably, an inorganic material such as silica, diamond-like carbon, or alumina is vapor deposited and coated to improve gas permeability.
Further, a metal material such as stainless steel may be used for the jacket material and welded.

  Moreover, when polyethylene is used for the heat welding layer 13, since polyethylene can be welded at a relatively low temperature, welding by additional heating is easy, and the vacuum heat insulating material 4 can be provided at a lower cost.

  Further, a protective layer made of polyethylene terephthalate may be provided on the outermost layer of the jacket material 11. By disposing a material for the purpose of surface protection in the outermost layer of the jacket material 11 in this way, it has a function of suppressing the occurrence of pinholes by exhibiting more reliable scratch resistance and puncture resistance. And the vacuum heat insulating material 4 which has long-term reliability can be provided, and also the vacuum heat insulation box 1 which has long-term reliability can be provided. Also. Polyethylene terephthalate is an inexpensive material and can provide the vacuum heat insulating material 4 at a lower cost.

  As the fibrous core material 12, short glass fibers are suitable as a general-purpose industrial material. More preferably, the fiber assembly is composed of a laminate of short glass fiber webs, and the webs are joined by the minimum amount of fiber entanglement that can maintain the integrity of the laminate, and are uniformly laminated in the thickness direction. Is preferred.

  The fiber diameter is not particularly specified, but finer fiber diameter can provide better heat insulation performance. However, from the viewpoint of economy, it is desirable to use one having an average fiber diameter of 3 to 5 μm.

  Moreover, as a gas poorly permeable material which comprises the outer box 2 and the inner box 3, metal materials, such as stainless steel and iron, and glass material are preferable. Since a glass material is easily broken, a metal material is more preferable.

  In addition, when using a resin material whose solid thermal conductivity is smaller than that of metal and can improve heat insulation performance, and which has a small specific gravity and can be reduced in weight, an ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, MX nylon It is preferable to use a gas permeable resin such as polyvinyl alcohol, crystalline polyethylene terephthalate, or crystalline syndiotactic polystyrene.

  Furthermore, in order to improve the low gas permeability, vapor deposition / coating of resin with insert molding of AL foil laminate film and AL vapor deposition laminate film, and inorganic materials such as silica, diamond-like carbon and alumina on the surface Is more preferable in order to improve reliability.

  In addition, the fibrous core material is not limited, and glass fiber, glass fiber, alumina fiber, silica alumina fiber, silica fiber, rock wool, silicon carbide fiber, etc. are preferable. In particular, glass fiber is inexpensive and has high performance vacuum insulation. Most desirable for forming the material. The glass fiber is preferably in the range of 1 μm to 20 μm, more preferably 2 μm to 10 μm with rigidity as a core material, and more preferable in terms of productivity and thermal conductivity.

  Further, although the powder core material is not limited, the inorganic powder material is preferable because it originally retains the powder and generates less gas (outgas) from the powder during decompression.

  In the first embodiment, the fiber core material 12 is used as the core material of the vacuum heat insulating material 4. However, the fiber core material need not be limited to a fiber core material, and may be a powder core material.

  Further, although the powder core material is not limited, the inorganic powder material is preferable because it originally retains the powder and generates less gas (outgas) from the powder during decompression.

  Furthermore, the powder core material is preferably dry silica having an average primary particle diameter of 100 nm or less. As the core material, the powder material in which the air gap distance is shorter is more excellent in pressure dependency, and therefore is superior to the fiber material in order to obtain long-term reliability. In addition, the solid thermal conductivity is low, and a silica-based material is excellent as a core material for a vacuum heat insulating material as a powder core material. Moreover, since the average primary particle diameter is 100 nm or less, the particle size is excellent in that the heat insulation performance with respect to the internal pressure is small, and such silica powder corresponds to dry silica produced by a dry method.

  Moreover, heat insulation performance improves rather than the vacuum heat insulating material which used only dry silica powder by mixing 1-30 wt% of carbon black with dry silica.

  As powders added to dry silica to improve heat insulation performance, for example, carbon black and titanium oxide are known to work as radiation prevention materials at high temperatures, but the addition of carbon black greatly improves heat insulation performance at low temperatures. It can be seen. Although this reason is not certain, it is considered that solid heat conduction is reduced by some action of silica powder and carbon black.

  The addition amount of the powdery carbon material is preferably 1 to 30 wt%. This is because if the addition amount is too small, there is no effect of improving the heat insulation performance, and if it is too large, the heat insulation performance becomes dependent on the powdered carbon material and the heat insulation performance deteriorates, or gas generation increases under reduced pressure. This is because the heat insulation performance deteriorates.

  Further, as a composite of a fibrous core material and a powder core material, a glass fiber material is mixed in the dry silica, the glass fiber material has an average fiber diameter of 10 μm or less, and the content in the core material is 0. It is 5-40 wt%, and what was shape | molded by pressing is preferable.

  Although dry silica has excellent performance as a core material for a vacuum heat insulating material, it is difficult to handle because of its low density, and it is necessary to seal it once in a nonwoven fabric for filling, which increases costs and the number of processes. Therefore, solidifying and encapsulating dry silica is excellent in the process.

  As a solidification means, a general silica powder and a fiber material are mixed and stirred, and even if pressure-molded, it does not become a molded body. However, dry silica having an average primary particle size of 100 nm or less and a fiber material are mixed and added. A compact can be formed by pressure molding. This may be due to the fact that powders with small particle diameters cause intermolecular forces to act and the powders adhere to each other, or because they are dry, the surface functional groups are few and the mutual repulsion is so small that the powders are likely to adhere to each other. Therefore, in order to produce a molded body by a molding method such as pressurization, it is necessary to use dry silica having an average primary particle diameter of 100 nm or less and a fiber material.

  Further, by making the glass fiber material have an average fiber diameter of 10 μm or less, the specific surface area is increased because the fiber diameter of the glass fiber is small, that is, the surface energy is increased, and the glass powder is easily combined with the powder. Since it is a combination with good affinity, it is considered that it is easy to adhere to each other or due to their interaction. Therefore, when producing a molded body by a molding method such as pressure, a glass having an average fiber diameter of 10 μm or less By using a fiber material, a stronger molded body can be produced.

  Further, by using dry silica having a very fine particle diameter and a glass fiber material having a small fiber diameter, a molded body having almost no dusting can be obtained. This is because, as described above, the intermolecular force between powders having a small particle diameter, adhesion between powders due to a small number of surface functional groups, good affinity between silica and glass fibers, large surface energy of thin fiber materials, etc. Can be considered.

  In addition, a strong molded body can be obtained by the above combination, and a molded body having flexibility can be obtained because it has elasticity.

  The reason for this is considered to be that, since fibers having an average fiber diameter of 10 μm or less are used, flexural elasticity is improved and flexibility can be obtained.

  The fiber addition amount is 0.5 to 40 wt% because if the addition amount is too small, the shape of the molded body cannot be maintained, and if it is too much, the heat insulation performance becomes dependent on the fiber and the heat insulation performance is deteriorated. .

(Embodiment 2)
FIG. 3 is a cross-sectional view of the vacuum heat insulating material installed in the space of the vacuum heat insulating box according to Embodiment 2 of the present invention. In addition, the thing of the same name and effect | action as Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits description.

  In FIG. 3, in the vacuum heat insulating material 4, the heat welding layer 14 is heat welded along the fibrous core material 12, and the upper and lower heat welding layers 14 are integrated up to the fibrous core material 12. In addition, the thickness of the heat welding layer 14 is kept constant.

  Next, a manufacturing method for performing heat welding along the fibrous core material 12 will be described. When the vacuum heat insulating material 4 produced in the same manner as in the first embodiment is left in a constant temperature furnace at 130 ° C., which is higher than the temperature at which the heat welding layer 14 is welded, for about 10 minutes, the entire vacuum heat insulating material 4 is pressurized by atmospheric compression. Therefore, the entire vacuum heat insulating material 4 is heat-welded and heat-welded up to the fibrous core material 12.

  Since the heat-welded layer 14 is welded up to the fibrous core material 12, the range of the heat-welded layer 14 can be widened to improve the sealing performance, and the outer peripheral edge can be cut to the near vicinity. , The bulkiness is reduced, the urethane foam resin 5 is easily filled, and the area ratio of the high-performance vacuum heat insulating material 4 to the space 6 can be increased by reducing the outer peripheral end portion. Can be achieved. In addition, since the vacuum heat insulating material 4 is included in the space 6, the outer peripheral edge is cut out to the near end, the width of the heat-welded layer 14 becomes narrow, and air components easily enter the inside of the vacuum heat insulating material 4. Even if it becomes conditions, since the space 6 is a decompression space, it has sufficient reliability.

  The vacuum heat insulation box concerning this invention can maintain heat insulation performance over a long period of time. For this reason, if it uses it for cold storage apparatuses, such as a refrigerator, and thermal insulation apparatuses, such as an electric water heater, a rice cooker, a thermal insulation cooker, and a hot water heater, it will show the energy-saving effect excellent over the long term. Also, it can be applied to uses such as container boxes and cooler boxes that require cold storage.

  Also, it can be applied to any heat insulation applications such as thermal equipment such as heat pump thermal insulation tanks and physical objects to be protected from heat and cold by using the same technology to improve the efficiency of heat storage warming devices for automobiles.

Sectional drawing of the vacuum heat insulation box in Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material installed in the space of the vacuum heat insulation box in Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material installed in the space of the vacuum heat insulation box in Embodiment 2 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating box 2 Outer box 3 Inner box 4 Vacuum heat insulating material 5 Urethane foam resin 6 Space 7 Gas adsorbent for vacuum heat insulating box 10 Gas adsorbent for vacuum heat insulating material 11 Cover material 12 Fibrous core material

Claims (4)

A vacuum heat insulation box having a urethane foam resin inside a space formed by an outer box and an inner box made of a gas-impermeable material and having the space sealed under reduced pressure , wherein the vacuum heat insulation box is vacuum-sealed. The vacuum heat insulation box which has a vacuum double wall structure by providing the vacuum heat insulating material which carries out the pressure reduction sealing of the core material in the inside of the jacket material of a gas poorly permeable material further in the inside of the said space . The core material of the vacuum heat insulating material is a fibrous core material having orientation, and the vacuum is such that the orientation direction of the fibrous core material is substantially perpendicular to the heat transfer direction of the vacuum heat insulating box. The heat insulation box according to claim 1, wherein a heat insulating material is disposed. The vacuum heat insulating box according to claim 1 or 2, further comprising a gas adsorbing material for adsorbing the gas in the vacuum heat insulating material to the vacuum heat insulating material. The vacuum heat insulation box according to any one of claims 1 to 3, further comprising a gas adsorbent for adsorbing the gas in the space in the space.