Patent Description:
Unexamined <CIT> discloses a heat insulating box in which an inside of the heat insulating box is exhausted and evacuated to be a vacuum heat insulating material. Unexamined <CIT> discloses a vacuum heat insulating material in which a moisture adsorbent or a gas adsorbent that adsorbs invading moisture or air is further installed in advance in an outer packaging material made of a resin material having low gas permeability in order to secure heat insulation performance over a long period of time.

<CIT> relates to a gas-adsorbing device which is provided with a packaging bag having a gas barrier property and flexibility, a gas adsorbent vacuum sealed inside the packaging bag, and a porous member disposed adjacent to the gas adsorbent in a planar state inside the packaging bag. This device is used for diverse evacuated insulating materials.

The present disclosure provides a vacuum heat insulator capable of maintaining high heat insulation performance for a long period of time by avoiding deactivation of a gas adsorbent and maximizing adsorption capability of the gas adsorbent, and a heat insulating container and a heat insulating wall using the vacuum heat insulator.

A vacuum heat insulator according to the present disclosure includes an outer packaging material including a resin sheet, and a core material and a gas adsorption device each contained in the outer packaging material. The gas adsorption device includes a vacuum sealed container containing a gas adsorbing substance that adsorbs a gas, an opening pin that opens the vacuum sealed container by a physical load from an outside, and a load-bearing spacer that suppresses displacement of the opening pin to less than or equal to a predetermined amount.

In recent years, from the viewpoint of prevention of global warming, improvement of energy saving is strongly desired, and improvement of energy saving is an urgent problem also in household electrical appliances. In particular, in heat-retaining and cold-keeping devices such as refrigerators, freezers, and vending machines, a heat insulating material having excellent heat insulation performance is required from the viewpoint of efficiently using heat.

As a general heat insulating material, a material selected from a fiber material such as glass wool and a foam such as urethane foam is used. In order to improve the heat insulation performance of these heat insulating materials, it is necessary to increase a thickness of each of the heat insulating materials. However, in a case where a space to be filled with the heat insulating material is limited, for example, in a case where space saving is required or in a case where effective use of the space is required, it is difficult to apply the general heat insulating material described above.

Therefore, a vacuum heat insulating material has been proposed as a high-performance heat insulating material. The vacuum heat insulating material is a heat insulator in which a core material having a role of a spacer is inserted into an outer packaging material having a gas barrier property, and the inside is sealed by being depressurized.

This vacuum heat insulating material has heat insulation performance about <NUM> times that of urethane foam, and has excellent characteristics that sufficient heat insulation performance can be obtained even when the thickness is reduced.

Accordingly, the vacuum heat insulating material attracts attention as an effective means for improving energy saving property by improving heat insulation performance while satisfying customer's demand for increasing an internal volume of a heat insulating box.

For example, in a refrigerator, in a heat insulating box constituting a refrigerator body, a heat insulating space between an inner box and an outer box is filled with urethane foam by foaming. Then, a vacuum heat insulating material is additionally installed in the heat insulating space to enhance the heat insulating property. This increases the internal volume of the heat insulating box.

Generally, a heat insulating space of a heat insulating box such as a refrigerator has a complicated shape. On the other hand, since it is generally difficult to perform processing that follows a complicated shape, particularly processing in a thickness direction, the vacuum heat insulating material is provided in a flat plate shape. For this reason, there is a limit to improvement of an area that can be covered by the vacuum heat insulating material, in other words, a ratio of the area of the vacuum heat insulating material to a total heat transfer area of the heat insulating box.

Therefore, for example, a technique has been proposed in which a heat insulating space of a heat insulating box is filled with open-cell urethane from an air feeding inlet port for blow molding of the heat insulating box and the open-cell urethane is foamed, and then the inside of the heat insulating box is exhausted and evacuated by a vacuum evacuation device connected to the air feeding inlet port, thereby forming the heat insulating box itself as a vacuum heat insulating material (See, for example, <CIT>).

Similarly to <CIT>, the present applicant has also proposed a technique in which a heat insulating space of a heat insulating box to be a refrigerator body is filled with open-cell urethane and the open-cell urethane is foamed, and then vacuuming is performed to make the heat insulating box itself a vacuum heat insulating material.

For the heat insulating space having a complicated shape, a vacuum heat insulator suitable for the complicated shape can be obtained as follows. That is, for each of the inner box and the outer box, an outer packaging material molded in accordance with a desired heat insulating space is produced by blow molding or vacuum molding a resin. Then, a core material obtained by foaming a resin such as open-cell urethane forming the heat insulating space itself is covered with an outer packaging material, and the inside is vacuum-sealed.

The heat insulator thus obtained in the heat insulating space having a complicated shape has higher overall heat insulation performance than a conventional heat insulator including a planar vacuum heat insulating material and urethane foam for filling gaps between the vacuum heat insulating material, and the inner box and the outer box. Therefore, it is possible to produce an effect of reducing the thickness of the heat insulating material to increase the internal volume or an effect of reducing the appearance, and an effect of reducing the weight.

As described above, the vacuum heat insulator formed by vacuum-sealing open-cell urethane as the core material and the resin molding material as the outer packaging material can vacuum-insulate the entire area of the heat insulating space even when the vacuum heat insulator has a complicated external appearance like a heat insulating box. Accordingly, by using such a vacuum heat insulator in, for example, a refrigerator, the thickness of the heat insulating box itself can be reduced, and the internal capacity (storage space) can be further increased.

Further, such a vacuum heat insulator is not complicated in shape, but can be applied to applications in which heat insulating properties are strongly expected, for example, an LNG storage tank for storing an ultra-low temperature substance such as liquefied natural gas (LNG), or a panel for a heat insulating container such as a tank of an LNG transport tanker. This makes it possible to effectively suppress intrusion of heat into the heat insulating container while reducing a wall thickness of the heat insulating container. Therefore, in the case of the LNG tank, the generation of a boil-off gas (BOG) can be effectively reduced, and a natural vaporization rate (boil-off rate, BOR) of LNG can be reduced.

In such a vacuum heat insulator, in order to secure heat insulation performance over a long period of time, a resin material having low gas permeability is used as an outer packaging material, and a moisture adsorbent or a gas adsorbent that adsorbs invading moisture or air is installed in the vacuum heat insulator in advance (See, for example, <CIT>).

When the gas adsorbent is exposed to an atmospheric pressure before evacuation, the gas adsorbent is immediately deactivated because of its very high adsorption rate, and after evacuation, the gas adsorbent is brought into a state of hardly adsorbing any more gas. For this reason, conventionally, the gas adsorbent is sealed in a vacuum sealed container in advance, and the container of the gas adsorbent is opened by some method from the outside after a state in which there is almost no residual gas around the gas adsorbent after evacuation. As a result, the gas adsorbent exhibits its original adsorption capability.

That is, the container of the gas adsorbent should not be already opened when the container is to be opened, or should not be unopened when the container is to be opened. In the former case, it is considered that the gas adsorbent is already deactivated when it is desired to open the container of the gas adsorbent, and in the latter case, the performance of the gas adsorbent cannot be exhibited at all. In either case, regardless of the initial performance, a degree of vacuum cannot be maintained for a long period of time, and there is a problem that the heat insulation performance of the vacuum heat insulating material cannot be maintained.

The inventors have found that there is a problem as described above, and have come to constitute the subject matter of the present disclosure in order to solve the problem.

The present disclosure provides a vacuum heat insulator capable of maximizing adsorption capability of a gas adsorbent and maintaining high heat insulation performance over a long period of time, and a heat insulating container and a heat insulating wall using the vacuum heat insulator.

Exemplary embodiments will be described in detail below with reference to the drawings. However, an unnecessarily detailed description will be omitted in some cases. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted.

Note that the accompanying drawings and the following description are provided to help those skilled in the art to fully understand the present disclosure and are not intended to limit the subject matter recited in the claims.

A first exemplary embodiment will be described below with reference to <FIG>. <FIG> is a sectional view of refrigerator <NUM> including vacuum heat insulator <NUM> according to the first exemplary embodiment. <FIG> is a perspective view of refrigerator door <NUM> to which vacuum heat insulator <NUM> is applied. <FIG> is a sectional view taken along line IIIA-IIIA in <FIG>. <FIG> is a sectional view taken along line IIIB-IIIB of <FIG>. <FIG> is a sectional view of vacuum heat insulator <NUM>. <FIG> is a sectional view taken along line IVB-IVB in <FIG>. <FIG> illustrates a sectional view and a top view of vacuum sealed container <NUM> included in gas adsorption device <NUM> included in vacuum heat insulator <NUM>. <FIG> illustrates a sectional view and a top view of gas adsorption device <NUM>. <FIG> is a diagram illustrating a configuration of an opening pin of gas adsorption device <NUM>. <FIG> is a flowchart illustrating a method of manufacturing refrigerator door <NUM> including vacuum heat insulator <NUM>.

Hereinafter, vacuum heat insulator <NUM> according to the present exemplary embodiment will be described with reference to an example applied to refrigerator door <NUM>.

In <FIG>, refrigerator <NUM> includes refrigerator door <NUM>. A foamed heat insulating material (not illustrated) is filled between outer box <NUM> and inner box <NUM> of refrigerator <NUM> to form heat insulating box <NUM>. Inside heat insulating box <NUM>, freezing chamber <NUM> and refrigerating chamber <NUM> partitioned by partitioning body <NUM> are disposed.

Compressor <NUM> is disposed in machine chamber <NUM> in an upper part of heat insulating box <NUM>, and evaporation pan <NUM> is disposed in lower machine chamber <NUM>. Evaporator <NUM> is disposed in cooling chamber <NUM> formed on a back surface of freezing chamber <NUM>.

Freezing chamber <NUM> and cooling chamber <NUM> are partitioned by cooling chamber wall body <NUM>. Refrigerator door <NUM> is disposed in each of front opening parts 7a of heat insulating box <NUM> corresponding to freezing chamber <NUM> and refrigerating chamber <NUM>.

As illustrated in <FIG>, refrigerator door <NUM> includes outer plate <NUM>, outside exterior appearance component <NUM>, inner plate <NUM>, and inside exterior appearance component <NUM>. Gas barrier layer <NUM> against oxygen and the like is formed inside outer plate <NUM>. Outside exterior appearance component <NUM> is disposed on a surface of outer plate <NUM> and is made of a glass plate, a metal plate, or the like. Gas barrier layer <NUM> against oxygen and the like is formed inside inner plate <NUM>. Inside exterior appearance component <NUM> is disposed on a surface of inner plate <NUM>, and is made of ABS resin or the like. Refrigerator door <NUM> includes open-cell urethane foam <NUM> (a core material of the vacuum heat insulator) filled in a heat insulating space between outer plate <NUM> and inner plate <NUM>. Here, outer plate <NUM> and inner plate <NUM> correspond to outer packaging material <NUM>.

Note that outer packaging material <NUM> wraps an outer surface of open-cell urethane foam <NUM> (the core material of the vacuum heat insulator).

Specifically, vacuum heat insulator <NUM> according to the present exemplary embodiment includes core material (open-cell urethane foam <NUM>) that serves as a spacer, and outer packaging material <NUM> having a gas barrier property. Vacuum heat insulator <NUM> is configured such that the core material is inserted into outer packaging material <NUM>, an inside of the vacuum heat insulator is depressurized through exhaust port <NUM> provided in a part of inner plate <NUM>, and the vacuum heat insulator is sealed using sealing material <NUM>. An outer periphery of each of outer plate <NUM> and inner plate <NUM> is bonded and sealed by thermal welding layer <NUM>.

Further, as illustrated in <FIG>, outside exterior appearance component <NUM> and inside exterior appearance component <NUM> are bonded to vacuum heat insulator <NUM> according to the present exemplary embodiment with an adhesive or the like to complete refrigerator door <NUM>.

Note that <FIG> illustrate a state before outside exterior appearance component <NUM> and inside exterior appearance component <NUM> of refrigerator door <NUM> are bonded to each other, that is, vacuum heat insulator <NUM> according to the present exemplary embodiment.

Next, a method of manufacturing refrigerator door <NUM> including vacuum heat insulator <NUM> according to the first exemplary embodiment will be described.

In <FIG>, outer plate <NUM> and inner plate <NUM> are made of a resin sheet having a high oxygen gas barrier property and a high water vapor gas barrier property. Outer plate <NUM> and inner plate <NUM> mainly need to be configured to suppress permeation of air and water vapor.

For example, a multilayer sheet in which an ethylene-vinyl alcohol copolymer resin (EVOH), which is a material having low oxygen permeability, is sandwiched between polypropylene, polyethylene, or the like, which is a material having low water vapor permeability, is prepared by an extrusion molding machine or the like in order to improve moldability (step <NUM>). Then, the multilayer sheet prepared in step <NUM> is molded into a shape conforming to the shape of a part where heat insulation is required by vacuum molding, pressure molding, blow molding, or the like (step <NUM>).

Note that a similar effect can be obtained by using polyvinyl alcohol (PVA) instead of EVOH. Inner plate <NUM> is provided with exhaust port <NUM> to which a welding mechanism (not illustrated) is connected, and inner plate <NUM> is sealed with sealing material <NUM> having at least a metal foil having a high oxygen gas barrier property.

When outer plate <NUM> is a complete plane, a resin laminate film containing a metal layer of aluminum, stainless steel, or the like is often used. This is because, by using a film, the thickness can be set to less than or equal to <NUM>, uniform heating is facilitated at the time of heat welding described later, and highly reliable vacuum heat insulator <NUM> can be obtained. However, when outer plate <NUM> is not a flat surface from the viewpoint of designability and the like, a resin sheet having a thickness of <NUM> or more is used similarly to inner plate <NUM>.

Open-cell urethane foam <NUM> is molded by injecting a urethane liquid into a metal mold (not illustrated) having a shape of a heat insulating space between outer plate <NUM> and inner plate <NUM>, and foaming and releasing the urethane liquid (step <NUM>, step <NUM>).

A method of manufacturing refrigerator door <NUM> will be described below with reference to <FIG>.

Next, a gas adsorbent that adsorbs various gases and gas adsorption device <NUM> (described later) are installed in box-shaped inner plate <NUM> together with open-cell urethane foam <NUM>.

Then, a molded article of open-cell urethane foam <NUM> is housed in inner plate <NUM> and covered with outer plate <NUM> (step <NUM>). Heat and pressure are applied to an outer peripheral part where inner plate <NUM> and outer plate <NUM> are in contact with each other, and inner plate <NUM> and outer plate <NUM> are thermally welded (step <NUM>).

At this time, as illustrated in <FIG> or <FIG>, when the adhesive layer (thermal welding layer <NUM>) between outer plate <NUM> and inner plate <NUM> is a polypropylene layer, the polypropylene resins are thermally welded.

As the gas adsorbent, gas adsorbent <NUM> that selectively adsorbs air or moisture adsorbent <NUM> that adsorbs moisture is known. This gas adsorbent adsorbs a remaining gas that cannot be exhausted by evacuation or a trace amount of gas that has permeated through inner plate <NUM> or outer plate <NUM> having a high gas barrier property in a long period of time, so that a degree of vacuum can be maintained for a long period of time.

As illustrated in <FIG>, gas adsorption device <NUM> includes vacuum sealed container <NUM>, opening pin <NUM>, and load-bearing spacer <NUM>. Vacuum sealed container <NUM> contains gas adsorbing substance <NUM> including zeolite or the like that adsorbs various gases. Opening pin <NUM> opens vacuum sealed container <NUM> by a physical load from the outside. Load-bearing spacer <NUM> suppresses displacement of opening pin <NUM> to less than or equal to a predetermined amount.

For example, as illustrated in <FIG>, opening pin <NUM> includes pin part <NUM> that opens vacuum sealed container <NUM>, spring part <NUM> that biases pin part <NUM> outward, and pin support part <NUM>. Pin support part <NUM> supports pin part <NUM> and has a function as a coupling part that couples pin part <NUM> and spring part <NUM>.

Returning to <FIG>, next, outer shapes of inner plate <NUM> and outer plate <NUM> that have been thermally welded are cut into predetermined shapes (step <NUM>).

Vacuum heat insulator <NUM> including inner plate <NUM> and outer plate <NUM> that are thermally welded is evacuated for a predetermined time through exhaust port <NUM> by a vacuum evacuation device (not illustrated) (step <NUM>). Then, exhaust port <NUM> is welded and sealed by ultrasonic welding or the like using sealing material <NUM> (step <NUM>). Accordingly, vacuum heat insulator <NUM> can be obtained.

In order to shorten the exhaust time and improve the productivity, it is desirable that a vent hole (not illustrated) of open-cell urethane foam <NUM> (core material) is connected to exhaust port <NUM>. Note that sealing material <NUM> includes an adhesive layer, a metal foil, and a heat-resistant protective layer (not illustrated) in this order from the one closest to exhaust port <NUM>.

The adhesive layer is disposed inside the metal foil. A melting point of the adhesive layer is less than or equal to <NUM>. The heat-resistant protective layer is disposed outside the metal foil. The heat-resistant protective layer is a heat-resistant layer having a melting point of higher than or equal to <NUM>.

Note that in the present exemplary embodiment, exhaust port <NUM> is substantially circular, and a hole diameter of exhaust port <NUM> is more than or equal to <NUM>.

Vacuum heat insulator <NUM> is aged at about <NUM> to <NUM> for several hours to several days after sealing of exhaust port <NUM> (step <NUM>). As a result, residual moisture in vacuum heat insulator <NUM> is adsorbed by moisture adsorbent <NUM>. Thereafter, as illustrated in <FIG>, gas adsorption device <NUM> including vacuum sealed container <NUM> in which gas adsorbing substance <NUM> is enclosed and opening pin <NUM> is pushed by physically applying a load through outer plate <NUM>, so that vacuum sealed container <NUM> is opened by opening pin <NUM> (step <NUM>). As a result, gas adsorbing substance <NUM> is exposed to a sealed space of vacuum heat insulator <NUM>, and it is possible to adsorb the residual gas excluding moisture and the gas entering from the outside through outer plate <NUM> or inner plate <NUM> over a subsequent long period. After step <NUM>, inside exterior appearance component <NUM> and outside exterior appearance component <NUM> are bonded to obtained vacuum heat insulator <NUM>, respectively (step <NUM>, step <NUM>), to complete refrigerator door <NUM>.

In gas adsorption device <NUM> of vacuum heat insulator <NUM> configured as described above in the present exemplary embodiment, load-bearing spacer <NUM> is provided between pin support part <NUM> that supports pin part <NUM> of opening pin <NUM> and vacuum sealed container <NUM> that contains gas adsorbing substance <NUM>. As a result, it is possible to prevent outer plate <NUM> from pushing opening pin <NUM> of gas adsorption device <NUM> and opening vacuum sealed container <NUM> due to a compressive stress applied to outer plate <NUM> by the atmospheric pressure after the step of evacuating vacuum heat insulator <NUM> shown in step <NUM>.

Load-bearing spacer <NUM> is provided for the purpose of preventing pin part <NUM> from approaching a distance less than or equal to a distance to vacuum sealed container <NUM> in which gas adsorbing substance <NUM> is sealed. Thus, load-bearing spacer <NUM> does not need to be located between vacuum sealed container <NUM> and pin part <NUM>, and may be located between vacuum sealed container <NUM> and pin support part <NUM>. A material used for load-bearing spacer <NUM> may be the same material as open-cell urethane foam <NUM> selected for the purpose of withstanding a compressive stress caused by atmospheric pressure.

In the opening step of vacuum sealed container <NUM> shown in step <NUM>, a load stronger than atmospheric compression, for example, a load of about <NUM> KPa is slowly applied to an immediate upper part of opening pin <NUM>. As a result, load-bearing spacer <NUM> is also compressed, and vacuum sealed container <NUM> in which gas adsorbing substance <NUM> is sealed is eventually opened by pin part <NUM>.

As described above, in the present exemplary embodiment, vacuum heat insulator <NUM> includes outer packaging material <NUM>, open-cell urethane foam <NUM> (core material), and gas adsorption device <NUM>. Outer packaging material <NUM> is made of a resin sheet (not illustrated). Open-cell urethane foam <NUM> is enclosed in outer packaging material <NUM>.

Gas adsorption device <NUM> includes vacuum sealed container <NUM>, opening pin <NUM>, and load-bearing spacer <NUM>. Vacuum sealed container <NUM> contains gas adsorbing substance <NUM> that adsorbs various gases. Opening pin <NUM> opens vacuum sealed container <NUM> by a physical load from the outside. Load-bearing spacer <NUM> suppresses displacement of opening pin <NUM> to less than or equal to a predetermined amount.

By providing load-bearing spacer <NUM> so that opening pin <NUM> does not approach vacuum sealed container <NUM> constituting gas adsorption device <NUM> by a distance or less due to a compressive stress by atmospheric pressure, it is possible to avoid opening of vacuum sealed container <NUM> during evacuation and before vacuum sealing. Therefore, it is possible to avoid that gas adsorbing substance <NUM> adsorbs a large amount of residual gas during evacuation and before vacuum sealing and the subsequent adsorption capability is impaired, so that the performance of vacuum heat insulator <NUM> can be maintained.

Further, after all the residual moisture is adsorbed by moisture adsorbent <NUM> after the vacuum sealing, vacuum sealed container <NUM> of gas adsorption device <NUM> is reliably opened by opening pin <NUM>, so that the degree of vacuum and the heat insulation performance of refrigerator door <NUM> can be maintained for a long period of time. Accordingly, refrigerator door <NUM> having high reliability can be provided.

Note that opening pin <NUM> includes pin part <NUM> that opens vacuum sealed container <NUM>, spring part <NUM>, and pin support part <NUM> (coupling part) that couples pin part <NUM> and spring part <NUM>. Since pin support part <NUM> of opening pin <NUM> is supported by load-bearing spacer <NUM>, it is possible to prevent outer plate <NUM> from pushing opening pin <NUM> of gas adsorption device <NUM> and opening vacuum sealed container <NUM> by the compressive stress applied to outer plate <NUM> due to the atmospheric pressure after the step of evacuating vacuum heat insulator <NUM>. Further, by pressing outer packaging material <NUM> from the surface of outer packaging material <NUM>, a force pressed from the surface of outer packaging material <NUM> is received by pin support part <NUM> when vacuum sealed container <NUM> of gas adsorption device <NUM> is opened by opening pin <NUM>. Therefore, pin part <NUM> can reliably open vacuum sealed container <NUM>.

Load-bearing spacer <NUM> is provided for the purpose of preventing pin part <NUM> from approaching vacuum sealed container <NUM> of gas adsorption device <NUM> by a certain distance or less. Therefore, load-bearing spacer <NUM> does not need to be between vacuum sealed container <NUM> and pin part <NUM>, and may be between vacuum sealed container <NUM> and pin support part <NUM>. Thus, when it is desired to open vacuum sealed container <NUM>, pin part <NUM> can be opened without being disturbed by load-bearing spacer <NUM>. Accordingly, vacuum degree and heat insulation performance of refrigerator door <NUM> can be maintained for a long period of time, whereby vacuum heat insulator <NUM> having high reliability can be provided.

Note that load-bearing spacer <NUM> needs to withstand atmospheric compression. Therefore, it is desirable that load-bearing spacer <NUM> has a compressive strength of <NUM> kPa or more at <NUM>% strain.

Note that load-bearing spacer <NUM> itself is also exposed to the vacuum space for a long period of time. Therefore, load-bearing spacer <NUM> is desirably made of a material that emits less gas. When open-cell urethane foam <NUM> used as the core material of vacuum heat insulator <NUM>, for example, is used as the material of load-bearing spacer <NUM>, evacuation is performed by vacuum evacuation similarly to the core material, and the residual gas is adsorbed by gas adsorbing substance <NUM>.

Note that vacuum heat insulator <NUM> according to the present exemplary embodiment is used as a heat insulating wall (not illustrated) used for an inner wall or an outer wall of a refrigeration device (not illustrated) or a refrigerator (not illustrated). Accordingly, it is possible to provide a heat insulating wall which is inexpensive and can maintain heat insulation performance for a long period of time. In addition, energy saving of the device can be enhanced.

A second exemplary embodiment will be described below with reference to <FIG>. <FIG> illustrates a perspective view and a component development perspective view of heat insulating container <NUM> according to the second exemplary embodiment. <FIG> is a sectional view of heat insulating container <NUM>. <FIG> is a sectional view taken along line VIIB-VIIB of <FIG>. <FIG> is a flowchart illustrating a method of manufacturing heat insulating container <NUM>.

In <FIG>, <FIG>, heat insulating container <NUM> according to the present exemplary embodiment includes outer box 27b, inner box 26b, and open-cell urethane foam 5b (core material) filling a heat insulating space between outer box 27b and inner box 26b. Gas barrier layer 31b against oxygen or the like is formed inside outer box 27b and inner box 26b. Here, outer box 27b and inner box 26b correspond to outer packaging material <NUM>.

Similarly to the configuration described in the first exemplary embodiment, in heat insulating container <NUM> serving as the vacuum heat insulator also in the present exemplary embodiment, the inside of outer packaging material <NUM> is decompressed through exhaust port 16b, and exhaust port 16b is sealed using sealing material 17b. Outer box 27b and inner box 26b are bonded and sealed by thermal welding layer 32b on the outer peripheries of outer box 27b and inner box 26b.

When the heat insulating space between outer box 27b and inner box 26b is filled with open-cell urethane foam 5b, air adsorbent 42b that selectively adsorbs air, moisture adsorbent 41b that adsorbs moisture, and gas adsorption device <NUM> described in the first exemplary embodiment are placed in the heat insulating space. The basic configuration of the vacuum heat insulator of heat insulating container <NUM> according to the present exemplary embodiment is similar to the configuration of the vacuum heat insulator according to the first exemplary embodiment so as to achieve effects similar to the effects described in the first exemplary embodiment.

<FIG> is a flowchart illustrating a method of manufacturing heat insulating container <NUM> in the present second exemplary embodiment. The basic manufacturing flow is the same as in steps <NUM> to <NUM> of the first exemplary embodiment.

In the case of heat insulating container <NUM>, neither outer box 27b nor inner box 26b has a planar shape. For this reason, a resin sheet having a thickness of <NUM> or more is used for both outer box 27b and inner box 26b.

In <FIG>, in the opening step of the gas adsorption device <NUM>, it is necessary to push opening pin <NUM> (see <FIG>) through a sheet thicker than that in first exemplary embodiment. Therefore, a load larger than that in the first exemplary embodiment, for example, a load of <NUM> MPa or more is slowly applied. As a result, load-bearing spacer <NUM> is also compressed, and vacuum sealed container <NUM> (see <FIG>) of gas adsorption device <NUM> is eventually opened by pin part <NUM> (see <FIG>).

In the present exemplary embodiment, inner plate <NUM> in the first exemplary embodiment corresponds to inner box 26b, and outer plate <NUM> corresponds to outer box 27b. By forming inner box 26b and outer box 27b into a box shape, it is possible to provide heat insulating container <NUM> that is inexpensive and can maintain high heat insulation performance over a long period of time.

Note that, in the vacuum heat insulators according to the first and second exemplary embodiments, gas adsorption device <NUM> is used for the purpose of maintaining the heat insulation performance of the vacuum heat insulating material with high reliability over a long period of time.

Gas adsorption device <NUM> is installed for the purpose of adsorbing a residual gas represented by nitrogen and oxygen and a gas represented by nitrogen and oxygen entering from the outside at a predetermined entry amount after sealing at a predetermined adsorption rate with respect to the vacuum heat insulating material vacuum-sealed after evacuation is performed for a predetermined time, and maintaining the vacuum heat insulating material at a predetermined equilibrium pressure.

A main factor of lowering the adsorption capability of gas adsorbent <NUM> is that gas adsorbent <NUM> already adsorbs the gas around gas adsorbent <NUM> before evacuation or during evacuation. In this case, an adsorption amount by gas adsorbent <NUM> does not reach an amount to be adsorbed originally.

Note that, as for moisture contained in the residual gas and the entering gas from the outside, originally, inexpensive moisture adsorbent <NUM> should be installed in the same space, and all of the moisture should be adsorbed by moisture adsorbent <NUM>, and the remaining nitrogen, oxygen gas, and the like should be adsorbed by gas adsorbent <NUM>. However, since gas adsorbent <NUM> adsorbs moisture, there is a case where gas adsorbent <NUM> cannot adsorb the gas to be originally adsorbed accordingly.

The present disclosure solves both of the above two problems. Specifically, the zeolite as gas adsorbing substance <NUM> is sealed in vacuum sealed container <NUM> until the vacuum heat insulating material is vacuum sealed after evacuation. Thereafter, the residual moisture is completely adsorbed by moisture adsorbent <NUM> for a predetermined time or under a temperature condition. Thereafter, vacuum sealed container <NUM> is opened by opening pin <NUM> or the like integrated with vacuum sealed container <NUM> of gas adsorbing substance <NUM> by a force physically applied from the outside. This makes it possible to adsorb gases other than surrounding moisture.

In this manner, the pressure is kept constant over a long period of time, so that the heat insulation performance of the vacuum heat insulating material can be reliably maintained over a long period of time.

Claim 1:
A vacuum heat insulator (<NUM>) comprising:
an outer packaging material (<NUM>) including a resin sheet; and
a core material (<NUM>) and a gas adsorption device (<NUM>) each contained in the outer packaging material (<NUM>),
wherein the gas adsorption device (<NUM>) includes
a gas adsorbing substance (<NUM>) that adsorbs a gas,
a vacuum sealed container (<NUM>) that contains the gas adsorbing substance (<NUM>),
an opening pin (<NUM>) that opens the vacuum sealed container (<NUM>) by a physical load from an outside of the vacuum sealed container (<NUM>),
characterized by
a load-bearing spacer (<NUM>) that suppresses displacement of the opening pin (<NUM>) to less than or equal to a predetermined amount.