JP4701882B2 - Vacuum insulation - Google Patents

Description

  The present invention relates to a vacuum heat insulating material and a method for manufacturing a vacuum heat insulating material.

  In order to maintain the heat insulation performance of the vacuum insulation material over a long period of time, the use of a film with excellent gas barrier properties as the jacket material prevents gas from entering from the outside and maintains the degree of vacuum inside the vacuum insulation material. There is a need. For this reason, conventionally, a film including a metal foil or a laminated film including a vapor deposition film has been widely used as the covering material.

  However, even if the barrier property of the film surface is strengthened, the end surface is in a state where a heat-welded layer having a high gas permeability is exposed, and thus measures against gas intrusion from the end surface are necessary.

  Thus, there is a vacuum heat insulating material provided with a thin strip portion in which a part of the heat-welded layer is thinned at a sealing portion of the jacket material (for example, see Patent Document 1).

  FIG. 9 is a cross-sectional view of a conventional vacuum heat insulating material described in Patent Document 1. As shown in FIG. 9, in the vacuum heat insulating material 1, a part of the heat welding layer 3 of the sealing portion of the outer covering material 2 is thin. This thin strip portion 4 is formed by applying particularly strong pressure to the sealing portion of the jacket material 2, and is formed so as to surround the entire circumference of the jacket material 2.

  In the conventional structure, the gas penetration resistance is increased by the thin strip portion 4, and the heat insulation performance can be exhibited over a long period of time by suppressing the gas penetration into the inside.

  Further, there is a vacuum heat insulating material whose end face is covered with a metal film (see, for example, Patent Document 2).

  FIG. 10 is a cross-sectional view of a conventional vacuum heat insulating material described in Patent Document 2. As shown in FIG. 10, the vacuum heat insulating material 5 has an end surface covered with another metal film 6 and has a configuration in which the entire circumference of the vacuum heat insulating material 5 is surrounded by a metal material.

  In the conventional configuration, the metal film 6 on the end face suppresses gas intrusion, so that the vacuum can be maintained for a long time.

  Moreover, there is a method for manufacturing a vacuum heat insulating material whose end face is covered with one film of the jacket material (see, for example, Patent Document 3).

  FIG. 11 is a cross-sectional view of a conventional vacuum heat insulating material described in patent literature. As shown in FIG. 11, the vacuum heat insulating material 7 has a configuration in which an end surface is covered with one film 8. This means that one film 8 is sized to protrude beyond the other film 9, and the protruding portion is folded back along the other film 9 and folded on the other film 9, and then the folded portion is sealed. It is obtained by.

In the conventional configuration, since the heat-welded layer formed on the inner surface is not exposed to the outside by setting the heat-welded layer on the end face to two or more layers, the decrease in the degree of vacuum inside can be suppressed and the heat insulation performance can be maintained. .
Japanese Utility Model Publication No. 62-141190 Japanese Patent Laid-Open No. 61-240084 JP 2000-104889 A

  However, in the said patent document 1, in order to form the thin strip part 4, a film (cover material 2) is heated, applying a very strong force again to the part once welded. For this reason, there existed a subject that deterioration of the film (cover material 2) by a heat | fever occurred.

  Moreover, in the said patent document 2, since another material (metal film 6) for covering an end surface is needed, material cost will UP. Moreover, since the metal film 6 at the end becomes a thermal bridge, there is a problem that the heat insulating performance is deteriorated.

  Moreover, in the said patent document 3, since the process of folding and a process of sealing is needed while material cost increases, manufacturing cost will also increase. In addition, since the heat-welded layer is the outermost layer of the film, there are problems such as easy sticking to the seal bar and reduced manufacturing efficiency.

  This invention solves the said subject, and suppresses the gas penetration | invasion from an end surface, and aims at maintaining the heat insulation performance of a vacuum heat insulating material over this by this.

In order to achieve the above-mentioned object, the present invention comprises at least a core material and a jacket material comprising a laminate film having a heat-welding layer as an innermost layer and covering the core material, and the inside of the jacket material is decompressed. A sealed vacuum heat insulating material, wherein at least three sides of the outer cover material are formed by a heat seal weld and an ultrasonic seal weld, and the ultrasonic seal weld is the heat seal. It is a vacuum heat insulating material which has the part where the said heat welding layer was relatively thinned in the welding part by the said ultrasonic seal in the outer peripheral side rather than the welding part by. When using an ultrasonic seal, the heat-welded layer can be heated efficiently, so the film is more than the external heating method, which produces a temperature gradient such that the outermost layer of the jacket material typified by heat seal has the highest temperature. Damage to other layers is small. In addition, the ultrasonic seal is more suitable than other internal heating methods because it can easily form a concavo-convex shape in the welded portion by selecting the tip shape of the horn. In addition, ultrasonic seals can be used to dissolve most resins as long as they are thermoplastic resins.
Since there are many types of resins that can be deposited and can be welded compared to other internal heating systems, the range of materials for the thermal welding layer is wide. In addition, the ultrasonic seal generates vibration by ultrasonic waves and is welded by frictional heat at the film interface, so it is possible to remove interstitial materials such as core material adhering to the film interface by this vibration and to weld firmly. Is possible. In addition, since the heat-welded layer has a relatively thinned portion at the welded portion by ultrasonic sealing, the gas penetration resistance can be suppressed because the gas penetration resistance is increased. Moreover, even if the heat-welded layer is thinned, the engagement between the films becomes strong due to the uneven shape, so that the sealing strength can be ensured. Moreover, since the welding part by ultrasonic sealing was provided in the outer peripheral side rather than the welding part by heat sealing, the load to the film by thickness reduction can be reduced. Further, in the case of an ultrasonic seal, vibration is more easily transmitted on the outer side, so that welding is easy and removal of foreign matters is easy. As a result, heat insulation performance is maintained over a long period of time.

In another aspect of the present invention , there is provided a vacuum heat insulating material comprising at least a core material and a covering material made of a laminate film and covering the core material, wherein the inside of the covering material is sealed under reduced pressure. The welded part of at least three sides of the material is formed by a welded part by heat sealing and a welded part by high frequency seal, and the welded part by the high frequency seal is on the outer peripheral side than the welded part by the heat seal, and the jacket material The outermost layer resin is a vacuum heat insulating material covering the end face of the jacket material. When using a high-frequency seal, the desired resin layer can be efficiently heated. Therefore, the film is more than the external heating method that produces a temperature gradient such that the outermost layer of the jacket material represented by heat seal has the highest temperature. Damage to other layers is small. Moreover, since the welding part by a high frequency seal was provided in the outer peripheral side rather than the welding part by heat sealing, the load to a film can be reduced. Since the end surface of the outer cover material can be covered with the outermost resin layer of the outer cover material by high-frequency sealing, gas intrusion from the end surface is suppressed. By these, heat insulation performance can be maintained over a long period of time.

  Since the vacuum heat insulating material of the present invention suppresses gas intrusion from the end face, the heat insulating performance can be maintained over a long period of time.

The invention of the vacuum heat insulating material according to claim 1 is composed of at least a core material and an outer cover material that is made of a laminate film having a heat-welding layer as an innermost layer and covers the core material. A vacuum heat insulating material sealed under reduced pressure, wherein a welded portion of at least three sides of the outer cover material is formed by a welded portion by heat sealing and a welded portion by ultrasonic sealing , and the welded portion by ultrasonic sealing is the heat It is located on the outer peripheral side of the welded portion by the seal, and has a portion where the heat-welded layer is relatively thinned at the welded portion by the ultrasonic seal .

Here, heat sealing, an external heating method resulting in temperature gradient as the outermost layer is the highest temperature of the enveloping member, ultrasonic sealing, the temperature gradient as the welding surface of the covering material is the highest temperature an internal heating method resulting in.

The ultrasonic seal is a system in which ultrasonic waves are converted into vibrations, heat is generated by friction at the film interface, and welding is performed by this heat .

Therefore, if an ultrasonic seal is used, the heat-welded layer can be efficiently heated. Therefore, compared to an external heating method that generates a temperature gradient such that the outermost layer of the jacket material typified by heat seal becomes the highest temperature. Damage to other layers of the film is small. Since the weld layer can be thinned and the cross-sectional area can be reduced by ultrasonic sealing , gas intrusion from the end face is suppressed, and heat insulation performance can be maintained over a long period of time.

In addition, the welding part by ultrasonic sealing may or may not be adjacent to the welding part of the heat seal . Ru can shorten the length of the more and more fins to the adjacent (portions consisting only of having no envelope material insulation performance).

  Among the internal heating methods, the ultrasonic seal can easily form a concave-convex shape in the welded part or a bellows-like welded part by selecting the tip shape of the horn. It is more suitable than the method.

In addition, for the heat welding layer in the present invention, it is necessary to select a resin that can be welded by both heat sealing and ultrasonic sealing. However, if the ultrasonic sealing is a thermoplastic resin, most resins can be welded. Since there are many types of resin that can be welded compared to other internal heating methods, the range of materials for the heat-welded layer is wide.

  In addition, the ultrasonic seal generates vibration by ultrasonic waves and is welded by frictional heat at the film interface, so it is possible to remove interstitial materials such as core material adhering to the film interface by this vibration and to weld firmly. Is possible.

By providing a portion where the heat-welded layer is relatively thinned at the welded portion by ultrasonic sealing , the gas intrusion resistance is increased, so that gas intrusion can be suppressed. Moreover, even if the heat-welded layer is thinned, the engagement between the films becomes strong due to the uneven shape, so that the sealing strength can be ensured.

Although welding by ultrasonic sealing causes less damage to the film than welding by heat sealing , the load on the film due to thinning is not zero. Therefore, providing on the outer side of the welded part by heat sealing can reduce the load on the film due to thinning.

Further, in the case of an ultrasonic seal, vibration is more easily transmitted on the outer side, so that welding is easy and removal of foreign matters is easy.

The invention of the vacuum heat insulating material according to claim 2 is a vacuum heat insulating material comprising at least a core material and a jacket material made of a laminate film and covering the core material, wherein the inside of the jacket material is sealed under reduced pressure. The at least three sides of the jacket material are formed by a heat seal weld and a high frequency seal weld, and the high frequency seal weld is on the outer peripheral side of the heat seal weld. The outermost layer resin of the jacket material covers the end surface of the jacket material .

Here, the high-frequency seal is an internal heating method in which a temperature gradient is generated such that the interface of a desired resin becomes the highest temperature. In addition, the high frequency seal is a system in which a dielectric is placed in a high frequency electric field and molecules are vibrated to generate heat by friction between adjacent molecules, and this heat is used for welding, and welding other than the heat welding layer is also possible. .

When using a high-frequency seal, the desired resin layer can be efficiently heated. Therefore, the film is more than the external heating method that produces a temperature gradient such that the outermost layer of the jacket material represented by heat seal has the highest temperature. Damage to other layers is small. Moreover, since the welding part by a high frequency seal was provided in the outer peripheral side rather than the welding part by heat sealing, the load to a film can be reduced. Since the end surface of the outer cover material can be covered with the outermost resin of the outer cover material by high-frequency sealing, gas intrusion from the end surface is suppressed, and heat insulation performance can be maintained over a long period of time.

In addition, the weld part by a high frequency seal may or may not be adjacent to the weld part of the heat seal. Adjacent ones can reduce the length of the fins (the portion consisting only of the jacket material having no heat insulating performance).

  The details of the present invention will be further described below.

  The laminate structure of the jacket material of the present invention is not particularly specified. For example, the innermost heat-welding layer includes low-density polyethylene, linear low-density polyethylene (hereinafter abbreviated as LL), high-density polyethylene, unstretched polypropylene, polyacrylonitrile, unstretched polyethylene terephthalate, unstretched nylon, unstretched. An ethylene-polyvinyl alcohol copolymer resin or the like can be used and is not particularly specified. Further, an adsorbent may be contained in the heat welding layer.

  Moreover, in order to suppress gas intrusion from the outside, a metal foil, a vapor deposition film, a coating film, a vapor deposition coating film, or the like can be used. The metal foil is not particularly specified such as aluminum, stainless steel, iron or a mixture thereof. In addition, the material of the plastic film used as a base material for vapor deposition and coating is polyethylene terephthalate (hereinafter abbreviated as PET), ethylene-vinyl alcohol copolymer resin (hereinafter abbreviated as EVOH), polyethylene naphthalate (hereinafter abbreviated as PEN), Nylon, stretched polypropylene (hereinafter abbreviated as OPP), polyamide, polyimide and the like are not particularly specified.

  Further, the material for vapor deposition is not particularly specified such as aluminum, cobalt, nickel, zinc, copper, silver, silica, alumina, diamond-like carbon, and a mixture thereof. Further, the coating material is not particularly specified such as polyvinyl alcohol, polyacrylic acid resin or a mixture thereof. In addition, the stacking order of vapor deposition and coating in the vapor deposition coating film is not particularly specified.

  Further, it is possible to further provide a film on the outer layer or the intermediate layer for the purpose of improving pinhole resistance and abrasion resistance, imparting flame retardancy, and further improving barrier properties.

  Here, the film provided in the outer layer or the intermediate layer is not particularly specified for the type and the number of laminated layers such as nylon, ethylene / tetrafluoroethylene copolymer resin, PET, PEN, OPP, EVOH and the like. Moreover, a vapor deposition film and a coating film may be sufficient.

  The bag shape of the jacket material is not particularly specified, such as a four-side sealed bag, a gusset bag, a three-side sealed bag, a pillow bag, or a center tape seal bag.

  The core material is not particularly specified as long as it has a high porosity such as fiber, powder, foamed resin, porous body, and thin film laminate. For example, glass wool, glass fiber, alumina fiber, silica alumina fiber, silica fiber, rock wool, silicon carbide fiber, etc. can be used in the fiber system, silica, perlite, carbon black in the powder system, urethane foam, phenol in the foamed resin Foam, styrene foam, etc. can be used. Moreover, it is also possible to use these mixtures and a molded object.

  When the initial heat insulating performance is required, it is preferable to use a fiber in which fibers are laminated perpendicularly to the heat transfer direction or a molded body thereof, and when the time-insulating thermal performance is required, a powder or a powder molded body may be used.

  In order to further improve the initial heat insulation performance and the temporal heat insulation performance of the vacuum heat insulating material, it is possible to use a moisture adsorbent or a gas adsorbent. The type of adsorbent to be used is not particularly specified, and calcium oxide, magnesium oxide, barium oxide, zeolite, silica gel, hydrotalcite, etc. can be used. You may use it in combination. In order to improve the handleability, these adsorbents may be used in a bag having air permeability.

  The manufacturing method of the vacuum heat insulating material is not particularly specified, and it may be obtained by making a bag from the laminate film and then inserting the core into the jacket material and reducing the pressure inside to seal it. Alternatively, the core material and the jacket material may be installed in the vacuum chamber, and the portion containing the core material may be heat-welded in a state where the jacket material is along the core material.

  Here, in the case of the latter production method, since deterioration of the film due to heat applied to the entire surface of the outer cover material is considered, the resin used other than the heat welding layer with respect to the melting point of the resin used for the heat welding layer It is desirable to set the melting point of the material to be higher by 40 ° C.

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

(Embodiment 1)
FIG. 1 is a cross-sectional view of a vacuum heat insulating material according to Embodiment 1 of the present invention. In FIG. 1, the vacuum heat insulating material 10 is comprised from the jacket material 11, the core material 12, and the adsorption agent 13, and the welding part of the four sides of a jacket material is the heat welding part 14 by an external heating system, and internal heating. It consists of the heat welding part 15 by a system.

  First, the manufacturing method of the vacuum heat insulating material 10 is demonstrated.

  First, the two sides of the laminate film cut into the same size rectangle are faced to each other and the three sides are heat-sealed to produce the bag-shaped outer covering material 11.

  Next, the core material 12 and the adsorbent 13 which have been dried for about 1 hour in a drying furnace at 140 ° C. are inserted from the opening of the jacket material 11. This is installed in a chamber, the inside is decompressed to 10 Pa or less, and then the opening is heat sealed. Furthermore, under normal pressure, the vacuum heat insulating material 10 is obtained by ultrasonically sealing all four sides so as to be adjacent to the outside of the heat-sealed welded portion.

  The welded part by ultrasonic sealing has an uneven shape, and the width of the welded part by heat sealing and the width of the welded part by ultrasonic sealing are 10 mm, respectively.

  Next, the configuration of the vacuum heat insulating material 10 will be described.

  The jacket material 11 was made of two different laminated films. One of the outer cover materials 11 has a configuration in which the heat-welding layer is LL, the outer side is aluminum foil, the outer side is PET, and the outermost layer is nylon. The other is a structure in which the thermal weld layer is LL, EVOH having a vapor deposition layer on the outside, PET having the vapor deposition layer on the outside, and nylon being provided on the outermost layer, and the vapor deposition layers are laminated so as to face each other. Yes. The core material 12 is a molded body made of glass fiber, and the adsorbent 13 is calcium oxide.

  The outer surface of the welded portion 14 welded by heat sealing is welded by ultrasonic sealing, so that the heat-welded layer on the end face can be made thin, so that the cross-sectional area of the end face is reduced and the gas penetration resistance is increased. The penetration was suppressed and the heat insulation performance of the vacuum heat insulating material 10 was maintained.

  For this reason, even if the core material 12 is a fiber-type core material which is not excellent in pressure dependence, heat insulation performance can be maintained. Furthermore, since the ultrasonic sealing was performed under normal pressure, the capital investment cost could be reduced.

  In this embodiment, the four sides are finally ultrasonically sealed. However, even when the vacuum heat insulating material 10 is manufactured after the three sides are ultrasonically sealed when the bag is manufactured by heat-sealing the three sides. Good.

  Moreover, in this Embodiment, although the welding part 14 by heat sealing and the welding part 15 by ultrasonic sealing are adjacent, it does not need to be adjacent.

  Further, in the present embodiment, the concave and convex shape is provided in the welded portion 15 by ultrasonic sealing, but a configuration in which a concave and convex shape is not provided as shown in FIGS. 2 and 3 may be partially thinned.

  In the present embodiment, heat sealing is performed as the external heating method and ultrasonic sealing is performed as the internal heating method. However, the same effect can be obtained by combining other external heating methods and internal heating methods.

(Embodiment 2)
FIG. 4 is a cross-sectional view of the vacuum heat insulating material in Embodiment 2 of the present invention. In FIG. 4, the vacuum heat insulating material 16 is composed of a jacket material 17, a core material 18, and an adsorbent 19, and the welded portions on the four sides of the jacket material are a heat welded portion 20 and an internal heating method by an external heating method. It consists of the heat welding part 21 by.

  First, the manufacturing method of the vacuum heat insulating material 16 is demonstrated.

  First, two sheets of laminate film cut into a rectangle of the same size are faced to each other and the three sides are heat-sealed to produce a bag-shaped outer covering material 17.

  Next, the core material 18 and the adsorbent 19 which have been dried for about 1 hour in a drying furnace at 140 ° C. are inserted from the opening of the jacket material 17. This is installed in a chamber, the inside is decompressed to 10 Pa or less, and then the opening is heat sealed.

  Furthermore, under normal pressure, the vacuum heat insulating material 16 is obtained by ultrasonically sealing all four sides so as to be adjacent to the outside of the heat-sealed welded portion. In addition, the welding part 21 by ultrasonic sealing has a bellows shape, and the width of the welding part 20 by heat sealing and the width of the welding part 21 by ultrasonic sealing are each 10 mm.

  Next, the configuration of the vacuum heat insulating material 10 will be described. The configuration of the jacket material 17, the core material 18, and the adsorbent 19 are the same as those in the first embodiment.

  By welding the outside of the welded portion 20 welded by heat sealing in a bellows shape by ultrasonic sealing, the gas intrusion path can be lengthened, so that gas intrusion can be suppressed and the heat insulating performance of the vacuum heat insulating material 16 can be maintained. For this reason, even if the core material 18 is a fiber-type core material which is not excellent in pressure dependence, heat insulation performance can be maintained. Furthermore, since the ultrasonic sealing was performed under normal pressure, the capital investment cost could be reduced.

  In this embodiment, the four sides are finally ultrasonically sealed. However, even when the vacuum heat insulating material 16 is produced after the three sides are ultrasonically sealed when the bag is produced by heat-sealing the three sides. Good.

  Further, in the present embodiment, the welded portion 20 by heat sealing and the welded portion 21 by ultrasonic sealing are adjacent to each other, but may not be adjacent.

  In the present embodiment, heat sealing is performed as the external heating method and ultrasonic sealing is performed as the internal heating method. However, the same effect can be obtained by combining other external heating methods and internal heating methods.

(Example 1)
In Embodiment 1, ultrasonic sealing was performed so as to be adjacent to both the inside and the outside of the welded portion 14 by heat sealing (see FIG. 5). The width of the welded portion 14 by heat sealing is 10 mm, and the width of the welded portion 15 by ultrasonic sealing is 5 mm both inside and outside.

(Example 2)
In Embodiment 1, ultrasonic sealing was performed so as to be adjacent to the inner peripheral side of the welded portion 14 by heat sealing (see FIG. 6). The width of the welded portion 14 by heat sealing is 10 mm, and the width of the welded portion 15 by ultrasonic sealing is 10 mm.

(Example 3)
In Embodiment 1, high frequency sealing was performed instead of ultrasonic sealing, and the outermost nylon layer was welded (see FIG. 7).

  In any of Examples 1 to 3, since the gas intrusion was suppressed as compared with the case of only welding by the external heating method, the heat insulation performance with time was improved.

  Comparing the first embodiment with the first and second embodiments, the first embodiment has the best thermal insulation performance even though the total weld area is the same. This was the order of Example 2. While the first embodiment performs ultrasonic sealing only on the outer side of the welded portion 14 by heat sealing, it is performed on both sides in Example 1 and only on the inner peripheral side in Example 2. Therefore, when sealing by the internal heating method is performed on the inner peripheral side of the welded portion by the external heating method, it is considered that a load is applied to the film due to thinning, but the gas barrier property is affected.

  In Example 3, the outermost layer of nylon was welded with a high frequency seal, and the end portion was covered with nylon, thereby suppressing gas intrusion from the end face. When the outermost nylon is welded by the external heating method aiming at the same structure as this, since heat of 250 ° C. or more is applied to the jacket material 11, deterioration of other films is inevitable. However, since the nylon layer can be efficiently heated in the high frequency seal, the influence on other films can be reduced as much as possible.

(Comparative Example 1)
In Embodiment 1, heat sealing was performed twice instead of ultrasonic sealing (see FIG. 8). The second heat seal was performed on the same part as the first heat seal. In the second seal, both the temperature and the pressure were increased compared to the first because the thickness of the heat-welded layer was reduced. In addition, the width of the welding part 14 by two times of heat sealing is 20 mm in total.

  Since the film was deteriorated due to high heat and high pressure due to repeated heat sealing, the improvement effect due to thinning of the heat-welded layer could not be obtained.

  As mentioned above, since the vacuum heat insulating material concerning this invention is excellent in the gas barrier property of a jacket material, it can maintain heat insulation performance over a long period of time. For this reason, if it uses it for cold insulation 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. Further, the present invention is not limited to heat insulation and cold equipment, but can also be applied to office equipment such as notebook computers, copiers, printers, projectors, and applications that require cold preservation such as container boxes and cooler boxes. Furthermore, it can be used as a building material, and can be applied to uses such as cold protection equipment and bedding.

Sectional drawing of the vacuum heat insulating material in Embodiment 1 of this invention Sectional drawing which shows the modification of the vacuum heat insulating material in the embodiment Sectional drawing which shows another modification of the vacuum heat insulating material in the embodiment Sectional drawing of the vacuum heat insulating material in Embodiment 2 of this invention Sectional drawing of the vacuum heat insulating material in Example 1 of Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material in Example 2 of Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material in Example 3 of Embodiment 1 of this invention Sectional drawing of the vacuum heat insulating material in the comparative example 1 Cross section of conventional vacuum insulation Cross section of another conventional vacuum insulation Sectional view of yet another conventional vacuum insulation

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vacuum heat insulating material 11 Cover material 12 Core material 14 Thermal welding part by external heating method 15 Thermal welding part by internal heating method 16 Vacuum heat insulating material 17 Cover material 18 Core material 20 Thermal welding part by external heating method 21 Internal heating method Heat welded part

Claims (2)

A vacuum heat insulating material comprising at least a core material and a jacket material made of a laminate film having a heat-welding layer as an innermost layer and covering the core material, wherein the outer shell material is sealed under reduced pressure, A welded portion of at least three sides of the material is formed by a welded portion by heat sealing and a welded portion by ultrasonic sealing , and the welded portion by ultrasonic sealing is on the outer peripheral side than the welded portion by heat sealing, The vacuum heat insulating material which has the part by which the said heat welding layer was relatively thinned in the welding part by a sound wave seal . A vacuum heat insulating material comprising at least a core material and a covering material made of a laminate film and covering the core material, the inside of the covering material being sealed under reduced pressure, and a welded portion on at least three sides of the covering material Is formed by a welded part by heat sealing and a welded part by high-frequency seal , the welded part by the high-frequency seal is located on the outer peripheral side of the welded part by the heat seal, and the outermost layer resin of the jacket material is the outer Vacuum insulation material covering the end face of the workpiece .

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