JP2008249003A - Vacuum insulation panel and equipment provided with the same - Google Patents

Abstract

【Task】
Provided are a vacuum heat insulating panel that has high heat insulating performance and can be used at a high temperature, and an apparatus including the heat insulating panel.
[Solution]
This is a vacuum insulation panel that consists of a jacket material made of metal foil such as stainless steel foil, a core material made of glass wool inorganic fiber and containing no binder, and a getter agent that adsorbs gas. The vacuum sealing is characterized in that it is made of glass provided in the form of a frame edge at the peripheral edge of the jacket material. Moreover, this invention is an apparatus which has heat insulation boxes, such as a refrigerator using the high temperature heat generating body and the said vacuum heat insulation panel, and a cooking peter.
[Selection] Figure 1

Description

  The present invention relates to a vacuum thermal insulation panel that shields thermal effects. Moreover, it is related with the heat insulation box which consists of a high temperature part heat generating body and a vacuum heat insulation panel, and an apparatus using the same.

  In recent years, from the viewpoint of global warming, energy reduction such as power consumption is desired for various products including home appliances. For example, if the amount of power consumed by the refrigerator is constant, the energy consumed can be reduced by improving the heat insulation performance of the heat insulating material involved in the efficiency of the cooling compressor and the amount of heat leakage.

  Vacuum insulation panels can be used in refrigerators, freezers, etc., because their thermal conductivity can be reduced compared to insulation materials such as polyurethane foam. The structure of the vacuum heat insulating panel is such that a core material serving as a core material and a getter agent that adsorbs outgas are placed in an outer cover material, and the inside is decompressed. As the covering material, an inexpensive organic film is used by adhering to the entire surface of the gas barrier layer with an adhesive by a laminating method. For example, a gas barrier layer is known in which an aluminum thin foil, an aluminum vapor deposition film, an eval film, a polyester film, etc. are bonded together and a nylon film is attached to a protective layer. A polyethylene film or a polypropylene film is used for the welding layer for sealing the jacket material.

  The application of a vacuum heat insulation panel is also desired around a heating element that is hotter than a refrigerator, such as a microwave oven, a heating cooker, a thermostatic bath, a copying machine, a laser printer, and a car. In order to improve the heat resistance of the vacuum heat insulating material for application to a high temperature part, it is necessary to increase the heat resistance of the jacket material and the heat resistance of the bonding part. For example, a heat insulating panel used for a microwave oven, a cooking heater, or the like needs to have a heat resistance of at least 250 ° C. or higher.

As a jacket material for high temperature, there is a laminate film for retort food. The heat resistance temperature of the laminate film using propylene homopolymer (CPP) for the weld layer is about 120 ° C. In order to further improve heat resistance, there is a method of welding an aluminum laminate thin foil with a metal. In JP 2005-300005 (Patent Document 1), a metal container made of a stainless sheet having a thickness of 30 to 100 μm and a metal plate that closes the upper surface opening of the metal container are welded or brazed. A vacuum insulation panel having a gas barrier container sealed and bonded is described. In the heat insulation panel, a foam foam-filled polyurethane foam, a glass wool mat used as a core material, housed in a container, and the inside is evacuated is used. Moreover, attaching the heat insulation panel to the heat insulation space of a refrigerator is described.

  In addition, Japanese Patent Application Laid-Open No. 2004-363221 (Patent Document 2) describes a method for vacuum-sealing the peripheral portion of a container or panel that uses a hollow portion in a vacuum. When sealing the peripheral edge, the sealing material is sandwiched between the opposing airtight surface materials, and the adhesive material pool is formed by extending the airtight surface material on the outside air side of the sealing material. An adhesive is applied to the contact portion between the hermetic face material and the sealing material of the part and joined together to prevent outside air from leaking into the vacuum part. In joining the periphery of the hermetic face material of the vacuum body, a sealing material is arranged between the hermetic face materials, and an adhesive material reservoir is provided between the air side or the airtight face material and the sealing material, and the adhesive material is applied. Have.

Japanese Patent Laid-Open No. 6-169850 (Patent Document 3) discloses a metal vacuum double container such as a portable thermos, a pot, and a jar. A metal inner and outer container is joined to form a double container, and one of the inner container and the outer container has an exhaust port, and the softening temperature is 200 to 600 ° C. in the vicinity of the exhaust port. The manufacturing method of the metal vacuum double container which arrange | positions the sealing material which becomes and softens a sealing material and seals the exhaust port of a double container is described. Examples of the low-temperature molten glass include B ₂ O ₃ —PbO, B ₂ O ₃ —ZnO, PbO—B ₂ O ₃ —ZnO—SiO ₂ , and PbO—B ₂ O ₃ —Al ₂ O ₃ —SiO _2. , PbO—B ₂ O ₃ —SiO ₂ system, PbO—
A B ₂ O ₃ —BaO—SiO ₂ system is used.

JP 2005-300005 A JP 2004-363221 A JP-A-6-169850

  When the metal foil of the jacket material becomes thicker, the thermal conductivity becomes very high. Therefore, it is preferable to use a thin foil of about 300 μm. However, there is a problem that the larger the heat insulation panel made of thin foil, the more easily defects such as cracks and pinholes are generated by welding. With current sizes (eg 200 × 1500 mm), it is very difficult to manufacture vacuum insulation panels using welded joints.

  The heat insulation panel described in Patent Document 1 forms a container by joining metal films by welding or brazing. However, joining by welding is suitable for producing a metal having a large metal thickness and a small shape, such as a metal double container such as a thermos. In welding, it is necessary to maintain parallelism during welding, and it is difficult to create a panel having a large shape by welding. Also, cracks and pinholes are likely to occur when the metal thickness is as thin as 500 μm or less due to stress concentration due to the removal of organic substances during welding and bending and impact during welding joining. For example, when a vacuum panel having a size suitable for a current refrigerator (for example, 200 × 1500 mm) is made of a thin metal foil, the metal used for the plate-like vacuum heat insulation panel is thin and has a large shape. Therefore, it is difficult to weld and bond the outer periphery of the vacuum heat insulating panel. In addition, in joining by brazing, since the brazing tends to be in a point-like sealed state, the vacuum degree may deteriorate with the passage of time when the temperature becomes high at 250 to 300 ° C., which guarantees heat resistance. Have difficulty. Therefore, it is difficult to produce a vacuum vessel by welding or brazing in a vacuum heat insulating panel having a large shape and using a thin metal thin film.

  In Patent Document 2, an adhesive material such as a plastic sealing material is used for sealing. Therefore, when the temperature is raised to 250 to 300 ° C., the degree of vacuum deteriorates with the lapse of time due to the generation of outgas, and the heat insulation performance is lowered, so there is a problem in obtaining a vacuum heat insulation panel intended for use under high temperature conditions. is there.

  In Patent Document 3, lead-based glass containing PbO is used. The use of lead is problematic due to environmental problems and the health of workers. Moreover, it is difficult to use a cylindrical heat insulating container by bonding, and a plate-like vacuum heat insulating panel is required.

  Accordingly, an object of the present invention is to provide a plate-like vacuum heat insulating panel having a high heat insulating effect, which generates less outgas even under high temperature use (250 to 300 ° C.) and is easy to manufacture.

  The feature of the present invention that solves the problem of the present application resides in a vacuum heat insulating panel using a glass adhesive as a bonding layer. The vacuum heat insulation panel of the present invention comprises an inorganic fiber core material formed into a plate shape, a getter agent that adsorbs gas and maintains the degree of vacuum inside, and a jacket material made of a metal foil. The peripheral portion of the substrate has a bonding layer that hermetically seals after enclosing the core material and the getter agent. The hermetically sealed jacket material is sealed under reduced pressure to form a plate-like heat insulation panel.

  The bonding layer is preferably formed in a frame shape on the peripheral edge of the metal foil to be welded. Compared with the case where the entire surface is provided with a bonding layer, the number of members used is reduced, and the cost can be reduced.

  Further, a glass material having a low gas permeability is used for the bonding layer. In particular, it is preferable to use a bismuth-containing low-melting glass not containing lead and having a thermal expansion coefficient of 10 ppm or more as the bonding layer. The bonding layer is preferably formed using a glass frit for sealing. Glass frit refers to glass flakes, glass powder and the like obtained by pulverizing a glass material.

  A bonding layer can be formed by applying a manufacturing method in which glass frit is mixed with a liquid to form a paste and thermocompression bonding is performed by screen printing or a roll coater.

  The metal foil is preferably a stainless steel foil. Compared to the most frequently used aluminum foil, the thermal conductivity can be lowered. The stainless steel foil has a coefficient of thermal expansion of 12 ppm or less, and a ferrite type is more preferable. The thickness of the stainless steel foil is preferably 50 to 500 μm. According to the present invention, it is possible to use a metal foil that is slightly thicker than before.

  Laminate films are often used in combination with aluminum foil, and stainless steel foil may be similarly laminated. In addition, by using a stainless steel foil without a laminate film, the manufacturing process can be reduced and the cost can be reduced.

  The core material is preferably glass wool having an average fiber diameter of 3 to 5 μm. This is because the thermal conductivity increases as the fiber diameter increases, and the handling becomes inconvenient when the fiber diameter is small. The core material does not include a binder such as a binder. This is to prevent outgassing from the binder and increase the thermal conductivity.

  Another aspect of the present invention is a heat insulating box using the vacuum heat insulating panel of the present invention. In a thermostatic bath, a microwave oven, an IH cooking heater, etc., in particular, a device or a heat generating part of 250 to 300 ° C. is provided inside the device. Power consumption can be reduced by using the vacuum heat insulation panel of the present invention around the heat generating part to cut off the heat effect.

  According to the said structure, the vacuum heat insulation panel which can be used at high temperature is realizable. Furthermore, it is possible to provide a vacuum heat insulating panel with little deterioration in heat insulating properties of the vacuum heat insulating panel even after use under high temperature conditions.

  Furthermore, energy consumption can be reduced by employ | adopting the vacuum heat insulation panel of this invention for the various products which have a high temperature part.

  The vacuum heat insulation panel of this invention is demonstrated with reference to FIG.

  Fig.1 (a) is a figure which shows the cross-sectional schematic diagram of the plate-shaped vacuum heat insulation panel of this invention. The vacuum heat insulation panel 5 covers the core material 3 of the inorganic fiber material that does not contain the binder and the getter agent 4 with the jacket material 1 made of a metal thin foil, and the peripheral portion is framed with the glass bonding layer 2. The inside is reduced in pressure and the inside is sealed. FIG. 1B is a perspective view of a bonding layer forming portion in which a frame-shaped bonding layer 2 is formed on the jacket material 1 made of metal foil.

  The glass bonding layer of the present invention is configured in a frame shape, and preferably has a thickness of about 10 to 30 mm and a thickness of about 10 to 100 μm. By forming a glass bonding layer having excellent oxygen permeability only in the bonding layer, it is possible to prevent various gases from passing and suppress outgas. It can also be used at high temperatures. Furthermore, the cost of the vacuum heat insulation panel can be reduced. Between the glass bonding layer and the jacket material, a layer for other purposes such as a layer for improving the bondability and a layer for increasing the strength of the jacket material may be provided in advance.

As the glass bonding layer, glass having a low oxygen permeability is used. The oxygen permeability is a permeation index such as H ₂ O, CO ₂ , O ₂ gas. The glass bonding layer has excellent bonding strength and suppresses the generation of outgas. Therefore, even when used at a high temperature, the heat insulating property is hardly deteriorated and the heat resistance is also improved. Note that gas permeation can be prevented by using glass having low oxygen permeability only for the bonding layer. In addition, the glass bonding layer has little deterioration in thermal conductivity over time. The glass bonding layer is preferably made of glass containing bismuth or phosphorus containing glass having a melting point of 400 to 500 ° C.

  Since these glasses are substantially free of lead, they have little environmental impact. By using a glass having a relatively low melting point, bonding is possible even at a low temperature of about 450 ° C. Note that the glass bonding layer can be formed using glass frit. In addition, the bonding layer of the present invention has excellent bonding strength even under a high temperature environment, and the thermal conductivity hardly deteriorates with time. Therefore, the durability of the vacuum heat insulation panel is improved.

  As the glass bonding layer, it is preferable to use glass having a thermal expansion coefficient of 10 ppm or more. Moreover, it is preferable that the metal outer packaging material is an outer packaging material using a metal having a coefficient of thermal expansion of 12 ppm or less. By combining the thermal expansion coefficient of the metal foil with the thermal expansion coefficient of the glass weld layer, the adhesive strength is improved. Moreover, there is little deterioration of the degree of vacuum at high temperature. In particular, the metal jacket material is preferably a ferritic stainless steel foil. Ferritic stainless steel has a coefficient of thermal expansion of 10.8 ppm and is compatible with glass, so the adhesion can be improved.

  The method for producing the bonding layer is not particularly limited, and can be appropriately performed using a coating film or the like. In particular, it is preferable to use a glass frit in a paste form with a resin or the like. The glass paste can be formed into a coating film by screen printing, roll coater or the like.

  The core material is made of an inorganic fiber material, and glass wool having an average fiber diameter of 3 to 5 μm is preferable. Thermal conductivity and cost vary greatly depending on the average fiber diameter of glass wool. In the case of the above fiber diameter, the heat flow path becomes zigzag, and the thermal resistance can be increased and the thermal conductivity can be lowered other than the contact resistance. Glass wool having a large average fiber diameter is preferable because of its low cost. Moreover, it is easy to handle the thickness of the core material and easy to handle. Further, glass wool having a small average fiber diameter is preferable because the fibers are less likely to be arranged in the same direction and the contact thermal resistance is large, so that the thermal conductivity is low. By using a core material whose fiber diameter falls within this range, the thermal conductivity can be lowered while suppressing the cost, and the deterioration of the thermal conductivity with time is small even when used at a high temperature. The inorganic fiber material preferably does not contain a binder. The reason why outgas is generated from the binder is that it is necessary to increase the amount of getter agent in order to maintain the thermal conductivity.

  The getter agent has a function of adsorbing the internal gas and keeping the thermal conductivity low, and needs to be sealed together with the core material in the jacket material. By providing the getter agent, the heat insulation effect is enhanced and the reliability of the vacuum heat insulation panel is enhanced. As the getter agent, gas adsorbent of dawsonite, hydrotalcite, metal hydroxide, etc. as necessary, or molecular sieves, silica gel, calcium oxide, zeolite, activated carbon, potassium hydroxide, sodium hydroxide, lithium hydroxide, etc. Any one of these moisture adsorbents or a mixture thereof is used.

  When the metal jacket material is thick, it is possible to increase the strength against piercing and tearing and to reduce the cost. The jacket material is particularly preferably stainless steel. In view of thermal conductivity, strength, and handleability, the thickness of stainless steel is preferably 50 to 500 μm.

  As the metal jacket material, a single layer or a plurality of layers of metal foil is used. In addition to stainless steel, iron, nickel, tin, titanium, carbon steel, etc. can be used. These metals are characterized by a small amount of heat flowing through the metal, and may be used in combination with the stainless steel. Moreover, you may use together metal vapor deposition films, such as aluminum, cobalt, nickel, and zinc. In the vacuum heat insulation panel of the present invention, a metal foil that is slightly thicker than the conventional one can be used.

  FIG. 2A shows the structure of a conventional vacuum heat insulation panel, and FIG. 2B is a schematic cross-sectional view of the vacuum heat insulation panel in which the welded portion is enlarged. FIG. 2A shows a vacuum heat insulation panel configured to cover the inorganic fiber core material 3 and the getter agent 4 with a jacket material 7, adhere the jacket material with a weld portion 9, and seal the inside under reduced pressure. The jacket material is made of a laminate layer of a polyethylene terephthalate film 8-1, a nylon film 8-2, and an aluminum foil 8-3.

  According to the configuration of the present invention, since a high-price heat-resistant film is not laminated on the entire surface unlike a conventional jacket material, the price can be reduced.

  Further, in the joining of the present invention, there is no problem of thinning like metal welding, and the size of the vacuum heat insulating panel is not a problem. That is, the necessity for maintaining parallelism during welding is reduced. Furthermore, stress is concentrated by bending or impact during welding, and the occurrence of cracks and pinholes in the metal foil is reduced, making it easy to produce a vacuum heat insulation panel.

  The vacuum heat insulation panel of the present invention can be appropriately used for a part requiring heat insulation such as home appliances. In particular, it can be suitably used for an oven, a range, a cooking heater, a hot water heater or the like that needs to keep a high temperature part, and a thing that needs to separate a high temperature part and a low temperature part. Examples of home appliances include refrigerators, air conditioner outdoor units, and other vehicles such as railways, medical inspection equipment, and thermostatic containers. The present invention is not limited to a high temperature of 250 to 300 ° C., and is preferable because it has excellent durability and can maintain heat insulation even when used under normal heating conditions of 250 ° C. or less.

  Next, the apparatus which inserted the vacuum heat insulation panel of this invention is demonstrated with reference to drawings. The heat insulation box body that maintains the temperature state of the heat-retained part of the present invention is provided around the heat-retained part heated at 250 to 300 ° C. and the heat-retained part, and covers the heat-retained part to maintain the temperature state. It is a heat insulation box which has the heat insulation member of this, Comprising: The said heat insulation member is the above-mentioned vacuum heat insulation panel, It is characterized by the above-mentioned. Even if it is a vacuum heat insulation panel used under a high temperature condition, the temperature-retained part becomes high temperature, and there is little decrease in heat insulation properties, and the energy consumption of the heat-retained part is reduced. Examples of application of the heat insulation box include a thermostatic bath, a microwave oven, and an IH cooking heater. With the above-described configuration of the present invention, an energy-saving device with low power consumption can be provided.

  FIG. 3 is a schematic cross-sectional view of a thermostatic chamber using the vacuum heat insulating panel 5. This is an example in which a vacuum heat insulation panel is used around the door 10 and the space 12 in the thermostatic chamber. The thermostatic bath is a device that keeps the inside of the chamber constituted by the main body and the door portion at a predetermined temperature with a heating element. In the example described in FIG. 3, it has a partition plate for appropriately partitioning the interior, and a vacuum heat insulation panel is built in the door and the main body portion. By insulating the outside air and the internal space with the vacuum heat insulating panel, the load on the heating element can be reduced.

  FIG. 4 is a schematic cross-sectional view of the microwave oven. This is an example in which the vacuum heat insulation panel 5 of the present invention is used for the main body part that forms the door 14 and the internal space 13 of the microwave oven. The microwave oven is a device that heats and cooks food or the like in a cabinet composed of a main body portion and a door portion. In the example described in FIG. 4, the vacuum heat insulation panel 5 of the present invention is used in the box constituting the main body and a part of the door. By insulating the outside air and the interior space with the vacuum heat insulating panel, it is possible to reduce the load on the heating element and shorten the cooking time, thereby reducing power consumption. In the case where there is no need to visually recognize the inside from the door during cooking, the vacuum heat insulation panel of the present invention can be disposed on the entire door, and the heat insulation can be further improved.

  FIG. 5 is a schematic sectional view of the IH cooking heater. This is an example in which the vacuum heat insulation panel 5 of the present invention is used in the periphery of the grill of the IH cooking heater. The IH cooking heater is heated using electromagnetic induction, and a current flows through the induction heater 16 to generate a line of magnetic force, and an eddy current generated by placing a cooking utensil such as a pot in the line of magnetic force It is the apparatus which cooks using the heat_generation | fever by the electrical resistance at the time of flowing through. Moreover, it is an apparatus which cooks food etc. by overheating by sending an electric current through the heater installed in the grill. The example described in FIG. 5 is an example in which the vacuum heat insulation panel 5 of the present invention is used in the periphery of the grill. By insulating the grill peripheral portion, the load on the heater can be reduced. Further, since the control circuit arranged on the side of the grill may be damaged by heat, conventionally, a sufficient space must be provided from the grill and disposed, and the capacity in the grill is limited. In the present invention, by disposing the vacuum heat insulating panel, it is possible to insulate in a small space compared to the conventional case, and the capacity in the grill can be increased.

  Hereinafter, the vacuum heat insulation panel of the present invention will be described in more detail by way of examples.

  The plate-shaped vacuum heat insulation panel was produced by the following steps.

First, two ferritic stainless steel foils (steel type: SUS430) are used for the metal foil jacket material.
(Size: 500 mm × 500 mm, plate thickness: 0.05 mm, coefficient of thermal expansion: 10.4 ppm), one was used as a metal foil plate as it was, and the other was used as a case formed into a dish shape by drawing. .

Thereafter, a bismuth glass (thermal expansion coefficient: 10.1 ppm) frit was mixed with a frit of a bismuth glass on the stainless steel foil plate side to form a paste, and a width of 10 mm and a thickness of 50 μm were applied by screen printing. Then, it was made to dry at 120 degreeC with a thermostat, and the organic substance in a paste was removed at 350 degreeC using the electric furnace. Bismuth glass is Bi ₂ O ₃ , B ₂ O ₃ , ZnO,
A glass mainly composed of SiO ₂ or the like and having a coefficient of thermal expansion and a melting point adjusted by the ratio of the above components was used.

  Put a core material (size: 400mm x 400mm x 20mm) made of glass wool with an average fiber diameter of 3µm in a stainless steel foil case formed in a dish shape. The chamber was evacuated until the internal pressure of the chamber became 1.3 Pa. After evacuation, the upper stainless steel foil plate was pushed by a pressurizing mechanism provided in the chamber and brought into close contact with the lower stainless steel foil dish case. At the same time, the portion coated with the glass frit was heated at 500 ° C. for 1 hour. Heating was performed using a heater at a heating rate of 10 ° C./min. Then, it cooled to 300 degreeC at 1 degree-C / min, and cooled naturally after that.

  The thermal conductivity of the vacuum heat insulation panel (thickness: about 8 mm) thus obtained was measured at 20 ° C. using AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. As a result, the thermal conductivity was 6.0 mW / m · K. Furthermore, after the plate-shaped vacuum heat insulation panel thus prepared was left in a thermostatic bath at 300 ° C. for 30 days, the thermal conductivity was measured again. As a result, it was 6.3 mW / m · K. Moreover, about the joining part of stainless steel foil and glass, it was in the state which was joined very firmly by combining the thermal expansion coefficient of both, and was a problem practically.

  From this, the vacuum thermal insulation panel of the present invention maintains its thermal conductivity without deterioration even at a very high temperature of 300 ° C., and reduces heat leakage by applying it to various devices having high-temperature parts. As a result, energy saving can be expected.

The thickness of the stainless steel foil of Example 1 is 0.1 mm, and the average fiber diameter of glass wool is 5
A vacuum heat insulation panel was similarly prepared by changing to μm. The resulting vacuum insulation panel had a thickness of about 8 mm. As a result of measuring the thermal conductivity, it was 6.5 mW / m · K. Furthermore, as a result of being left in a constant temperature bath at 250 ° C. for 30 days, the thermal conductivity after the test showed 6.9 mW / m · K. The joint between the stainless steel foil and the glass was in a state of no practical problem.

  The stainless steel foil of Example 1 was changed to the ferritic stainless steel foil of steel type SUS405, and the vacuum heat insulation panel was similarly produced. The ferritic stainless steel foil used has a plate thickness of 0.2 mm and a thermal expansion coefficient of 10.8 ppm. The average fiber diameter of glass wool was 4 μm, and the core material size was 400 mm × 400 mm × 25 mm. The thickness of the obtained vacuum heat insulation panel was about 10 mm. As a result of measuring the thermal conductivity, it was 6.4 mW / m · K. Furthermore, as a result of being left in a constant temperature bath at 250 ° C. for 30 days, the thermal conductivity after the test showed 6.8 mW / m · K. The joint between the stainless steel foil and the glass was in a state of no practical problem.

The stainless steel foil of Example 1 was changed to the ferritic stainless steel foil of steel type SUS405, and the vacuum heat insulation panel was similarly produced. The stainless steel foil used has a plate thickness of 0.5 mm and a thermal expansion coefficient of 10.8 ppm. The average fiber diameter of glass wool is 3 μm and the core material size is 400.
It was set to mm × 400 mm × 15 mm. The obtained vacuum insulation panel had a thickness of about 6 mm. It was 6.2 mW / m · K as a result of measuring thermal conductivity. Furthermore, as a result of being left in a thermostatic bath at 300 ° C. for 30 days, the thermal conductivity after the test showed 6.5 mW / m · K. The joint between the stainless steel foil and the glass frit was in a state of no practical problem.

A vacuum heat insulating panel was prepared in the same manner by replacing the ferrite stainless steel foil of Example 1 with a ferrite stainless steel foil having a thickness of 0.3 mm. As the glass adhesive layer, phosphorus-based glass (thermal expansion coefficient: 10.9 ppm) containing P ₂ O ₅ , SnO, and ZnO as main components was used. The average fiber diameter of the glass wool was 3 μm, and the core material size was 400 mm × 400 mm × 18 mm. The obtained vacuum insulation panel had a thickness of about 6 mm. As a result of measuring the thermal conductivity, it was 6.4 mW / m · K. Furthermore, as a result of being left in a thermostatic bath at 300 ° C. for 30 days, the thermal conductivity after the test showed 6.9 mW / m · K. The joint between the stainless steel foil and the glass frit was in a state of no practical problem.

The ferritic stainless steel foil of Example 1 was replaced with an austenitic stainless steel foil (steel type:
In the same manner, a vacuum heat insulation panel was prepared instead of SUS304. The used stainless steel foil has a thickness of 0.05 mm and a coefficient of thermal expansion of 17.3 ppm. As the adhesive layer, a glass frit paste having a thermal expansion coefficient of 8.5 ppm was used. The average fiber diameter of glass wool was 3 μm, and the core material size was 400 mm × 400 mm × 25 mm. The thickness of the obtained vacuum heat insulation panel was about 10 mm. As a result of measuring the thermal conductivity, it was 7.2 mW / m · K.

  Furthermore, as a result of leaving it for 30 days in a 300 degreeC thermostat, the heat conductivity after a test showed 9.8 mW / m * K.

  The vacuum heat insulation panel of this example is less likely to generate outgas from the adhesive layer as in Examples 1 to 5, and the production method is easy and preferable. However, after the heat resistance test, the heat conductivity is obtained but the heat conductivity is obtained. Was deteriorated.

  Although the vacuum heat insulation panel of the present example showed higher heat resistance than the conventional example, the strength of the joint between the stainless steel foil and the glass frit was weak, and handling was necessary. It seems that this result was obtained because the coefficients of thermal expansion of the two did not match.

The ferritic stainless steel foil of Example 1 was replaced with an austenitic stainless steel foil (steel type:
In the same manner, a vacuum heat insulation panel was prepared instead of SUS304. The stainless steel foil used has a plate thickness of 0.3 mm and a coefficient of thermal expansion of 17.3 ppm. As the adhesive layer, a glass frit paste having a coefficient of thermal expansion of 10.5 ppm was used. The average fiber diameter of glass wool was 6 μm, and the core material size was 400 mm × 400 mm × 25 mm. The thickness of the obtained vacuum heat insulation panel was about 10 mm. As a result of measuring the thermal conductivity, it was 9.1 mW / m · K. further,
As a result of leaving it in a thermostatic bath at 300 ° C. for 30 days, the thermal conductivity after the test showed 11.5 mW / m · K. The vacuum heat insulation panel of this example has less outgassing from the adhesive layer as in Examples 1 to 5, and the production method is easy and preferable. However, after the heat test, the heat insulation is obtained. Was deteriorated.

For this reason, the vacuum heat insulation panel of the present example showed higher heat resistance than the conventional example, but the strength of the joined portion of the stainless steel foil and the glass frit was weak, and handling was required. It seems that this result was obtained because the coefficients of thermal expansion of the two did not match.
[Comparative Example 1]

  The comparative example is an example in which a vacuum heat insulation panel was created using an organic film laminate as a jacket material and a polypropylene homopolymer as a weld layer.

  Glass wool having an average fiber diameter of 3 μm was used as a core material, and heated at 180 ° C. for 1 hour to remove moisture.

  The jacket material is filled with glass wool as a core material and a getter agent for gas adsorption, evacuated for 10 minutes with a rotary pump of the vacuum packaging machine and 10 minutes with a diffusion pump, and the internal pressure of the vacuum insulation panel is set to 1.3 Pa. The part was sealed with heat seal. The thermal conductivity of the obtained vacuum heat insulation panel (thickness: about 8 mm) was measured at 20 ° C. using an AUTO-Λ manufactured by Eihiro Seiki Co., Ltd. As a result, the initial thermal conductivity was 4.9 mW / m · K. Met. When left at 300 ° C. for 30 days, the welded portion was destroyed and it was difficult to measure the thermal conductivity. Therefore, when the polypropylene homopolymer is used as the weld layer, although the initial thermal conductivity is small, the heat resistance is as low as about 150 ° C., and it is difficult to use the vacuum heat insulating panel under high temperature conditions.

  Table 1 shows the results obtained from the above Examples and Comparative Examples.

  According to the present invention, by using a metal foil as a jacket material and a glass bonding layer at the joint, a vacuum heat insulating panel capable of supporting plate-like high temperature conditions having excellent thermal conductivity characteristics. Can provide. In addition, it is possible to suppress deterioration of the thermal conductivity characteristics with time, increase the strength of piercing and tearing, and reduce costs.

  Furthermore, by providing this vacuum heat insulation panel, a thermostat, a microwave oven, and an IH cooking heater can be used as devices with low power consumption.

The cross-sectional schematic diagram of the vacuum heat insulation panel of this invention. The cross-sectional schematic diagram of the conventional vacuum heat insulation panel. The thermostat provided with the vacuum heat insulation panel of the present invention. The microwave oven provided with the vacuum heat insulation panel of this invention. IH cooking heater provided with the vacuum heat insulation panel of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal outer packaging material 2 Joining layer 3 Inorganic fiber 4 Getter agent 5 Vacuum heat insulation panel 6 of this invention Conventional vacuum heat insulation panel 7 Cover material 8-1 Polyethylene terephthalate film 8-2 Nylon film 8-3 Aluminum foil 9 Welding part DESCRIPTION OF SYMBOLS 10 Constant temperature chamber door 11 Partition plate 12 Temperature chamber interior space 13 Range space 14 Range door 15 Top plate 16 Induction heater 17 Grill door 18 Grill glass 19 Grill handle 20 Control circuit 21, 22, 23 Heating element

Claims (11)

  An inorganic fiber core material; a getter agent; a jacket material made of a metal foil covering the core material and the getter agent; and a bonding layer that hermetically seals a peripheral edge of the jacket material, and the jacket material The vacuum heat insulation panel which decompressed the inside of this, Comprising: The said joining layer is the glass formed in the frame shape in the said jacket material, The vacuum heat insulation panel characterized by the above-mentioned.   2. The vacuum heat insulation panel according to claim 1, wherein the bonding layer has a glass thermal expansion coefficient of 10 ppm or more.   2. The vacuum heat insulation panel according to claim 1, wherein the bonding layer is made of glass containing bismuth having a melting point of 400 to 500 [deg.] C. and substantially free of lead.   2. The vacuum heat insulation panel according to claim 1, wherein the jacket material is made of a metal having a coefficient of thermal expansion of 12 ppm or less.   2. The vacuum heat insulation panel according to claim 1, wherein the metal outer packaging material is a ferritic stainless steel foil.   2. The vacuum heat insulation panel according to claim 1, wherein the core material is glass wool having an average fiber diameter of 3 to 5 [mu] m. A heat insulating box having a heat retaining part that generates 250 to 300 ° C. and a heat insulating member provided around the heat retaining part,
The heat insulating member has an inorganic fiber core material, a getter agent, a jacket material made of a metal foil covering the core material and the getter agent, and a bonding layer that hermetically seals a peripheral portion of the jacket material. A heat insulating box comprising a vacuum heat insulating panel in which the inside of the jacket material is decompressed, and the bonding layer is a glass formed in a frame shape on the jacket material.   The heat insulating box according to claim 7, wherein the bonding layer is made of glass having a coefficient of thermal expansion of 10 ppm or more, and the jacket material is a stainless steel foil having a coefficient of thermal expansion of 12 ppm or less. Insulated box.   A thermostat having a heating element, a main body that forms a space maintained at a predetermined temperature by the heating element, a door attached to the main body, and a partition plate that partitions the space as appropriate. At least the door part and the main body part incorporate a vacuum heat insulation panel, and the vacuum heat insulation panel comprises an inorganic fiber core material, a getter agent, and an outer layer made of a metal foil covering the core material and the getter agent. A glass having a bonding layer that hermetically seals a peripheral portion of the covering material and the covering material, the inside of the covering material is decompressed, and the bonding layer is formed in a frame shape on the covering material A thermostat characterized by being   An oven that has a heating element, a main body that forms a space heated to a predetermined temperature by the heating element, and a door that is attached to the main body, and that cooks food stored in the space. A vacuum heat insulating panel is built in at least a part of the door part and at least a part of the main body part, and the vacuum heat insulating panel includes an inorganic fiber core material, a getter agent, A jacket material made of a metal foil covering a core material and a getter agent, and a bonding layer that hermetically seals a peripheral portion of the jacket material, the interior of the jacket material is decompressed, and the bonding layer is A microwave oven characterized by being glass formed in a frame shape on the jacket material. An IH cooking heater having an induction heater unit for heating a cooking utensil using electromagnetic induction, a control circuit unit for controlling the induction heater, and a grill unit having a heating element,
A vacuum heat insulation panel is disposed between the grill part and the control part, and the vacuum heat insulation panel comprises an inorganic fiber core material, a getter agent, and a metal foil covering the core material and the getter agent. A glass having a bonding layer that hermetically seals a peripheral portion of the covering material and the covering material, the inside of the covering material is decompressed, and the bonding layer is formed in a frame shape on the covering material IH cooking heater characterized by being.

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