JP6634040B2 - Vacuum insulation material, method for manufacturing vacuum insulation material, and refrigerator - Google Patents

Description

  The present invention relates to a vacuum heat insulating material, a method for manufacturing the same, and a refrigerator provided with the vacuum heat insulating material.

2. Description of the Related Art As a social initiative to prevent global warming, energy saving has been promoted in various fields in order to reduce carbon dioxide (CO ₂ ) emissions. In recent years, electric appliances, particularly refrigerators, which are home appliances related to cooling and heating, have become mainstream with improved heat insulation performance from the viewpoint of reducing power consumption. For that purpose, a structure that has high heat insulation properties and does not allow the cold heat inside the refrigerator to escape to the outside of the refrigerator is essential.

  In general, a refrigerator includes a heat insulating box which is a refrigerator main body, and a storage room door which opens and closes a front opening of a storage room provided in the heat insulating box. In order to prevent the cold heat inside the refrigerator from escaping to the outside of the refrigerator, the heat insulating performance of the heat insulating box and the storage room door may be improved. In many cases, a vacuum heat insulating material and rigid urethane foam are arranged inside a heat insulating box or a storage room door to improve heat insulating performance. For example, a flat vacuum heat insulating material is attached to the inner surface of the outer box or the inner box of the heat insulating box, and rigid urethane foam is filled between the outer box and the inner box to suppress the transfer of cold heat. Further, for example, a flat vacuum heat insulating material is attached to the inside of the outer plate of the storage room door, and hard urethane foam is filled between the outer plate and the inner plate to suppress the transfer of cold heat.

  In recent years, research and development aimed at improving the heat insulating performance of vacuum heat insulating materials have been vigorously pursued. And such a vacuum heat insulating material is described in Patent Document 1, for example.

Patent Literature 1 includes a core material made of a glass fiber laminate in which glass fibers are laminated in a thickness direction, and an outer packaging material having a gas barrier property for covering the core material. A hermetically sealed vacuum insulation is described.
The core material of the vacuum heat insulating material is at a temperature at which the glass fiber starts to slightly deform under its own weight, or at a temperature at which the glass fiber can be deformed by a vertical load during pressing. Is molded under pressure at a temperature at which the cross-sectional shape of the glass fiber does not change significantly, and the glass fiber is stretched by thermal deformation.
Further, in this vacuum heat insulating material, some of the glass fibers are not tied to each other but are entangled between the fibers to maintain the shape.
Patent Literature 1 describes that the above-described configuration significantly improves the heat insulating performance of a vacuum heat insulating material.

Japanese Patent No. 3580315

  The raw cotton of the core material used for the vacuum heat insulating material described in Patent Document 1 is inserted into the outer packaging material (packaging body) because only a part of the glass fiber is entangled between the fibers to keep the shape. In doing so, there is a problem that glass fibers (inorganic fibers) are crushed and dimensional accuracy is deteriorated.

  In addition, as described above, in the vacuum heat insulating material described in Patent Document 1, only a part of glass fibers is entangled between fibers to keep the shape. When the package is torn or a part of the package is cut at the time of vacuum packaging, there is a problem in that the rate at which the thickness or shape returns to the original size (restoration rate) is high.

  The present invention has been made in view of the above circumstances, and has as its object to provide a vacuum heat insulating material having high dimensional accuracy and a low restoration rate, a method of manufacturing the same, and a refrigerator including the vacuum heat insulating material.

A vacuum heat insulating material according to the present invention that has solved the above-mentioned problem is a core material which is an aggregate of inorganic fibers, and a fusion layer formed by fusing at least a part of the inorganic fibers is formed on a surface of the aggregate. If, while enclosing the core material, inside have a, a packaging body is kept in a vacuum state, the thickness of the fusion layer is 0.1mm or more 2mm or less, in the thickness direction of the inorganic fibers The temperature after pressing at the intermediate position is lower than the strain point, the thickness of the inorganic fiber before pressing is 120 mm or more, and the thickness of the inorganic fiber immediately after pressing and the thickness of the inorganic fiber three days after pressing are represented by Δ (3 The restoration rate calculated by (thickness after day / thickness immediately after pressing) -1} × 100 is 25% or less .

The manufacturing method of the vacuum heat insulating material according to the present invention, the core material which is an aggregate of inorganic fibers is pressed at a temperature higher than the strain point of the inorganic fibers, at least a part of the inorganic fibers on the surface of the aggregate. A fusion layer forming step of forming a fusion layer that has been fused, a vacuum sealing step of enclosing the core material having the fusion layer formed therein in a package, and sealing the inside of the package while reducing the pressure inside the package; It has a, as well as the thickness of the bonding layer and 0.1mm or 2mm or less in the bonding layer forming step, the temperature after pressing the middle position in the thickness direction of the inorganic fibers lower than the strain point Then, the thickness of the inorganic fiber before pressing in the fusion layer forming step is 120 mm or more, and the thickness of the inorganic fiber immediately after pressing and the thickness of three days after pressing are represented by Δ (after three days) Thickness / thickness immediately after pressing) -1 x 100 Based index is a 25% or less.

The refrigerator according to the present invention is an aggregate of inorganic fibers, and includes a core having a fusion layer formed by fusing at least a part of the inorganic fibers on a surface of the aggregate, and including the core. And a package having an interior kept in a decompressed state, and a vacuum insulation material having an inner box formed by an outer box and an inner box, and a storage chamber formed in the insulation box. The inside of a storage room door formed by an outer plate and an inner plate that opens and closes, and the inside of a partition hot wall that partitions rooms having different storage temperature zones, and the fusion layer 0.1 mm or more and 2 mm or less, the temperature after pressing at an intermediate position in the thickness direction of the inorganic fiber is lower than the strain point, and the thickness of the inorganic fiber before pressing is 120 mm or more, and the pressing of the inorganic fiber is performed. From the thickness immediately after and the thickness three days after pressing, (3 days after the thickness / press immediately thickness) -1} recovery rate calculated in × 100 is present as 25% or less.

  According to the present invention, it is possible to provide a vacuum heat insulating material having high dimensional accuracy and a low restoration rate, a vacuum heat insulating material, a method for manufacturing the same, and a refrigerator provided with the vacuum heat insulating material.

It is an outline sectional view explaining the composition of the vacuum heat insulating material concerning this embodiment. It is a scanning electron microscope image which shows an example of an inorganic fiber. The magnification is 500 times, and the scale bar at the lower center in the figure represents 50 μm. It is a front view explaining the composition of the refrigerator concerning this embodiment. FIG. 4 is a sectional view taken along line AA of FIG. 3. It is a graph which shows the restoration | restoring amount of the thickness of a core material at the time of pressing for 10 minutes at each press temperature. It is a scanning electron microscope image of the inorganic fiber pressed at each press temperature. The magnification of the scanning electron microscope image is 200 times in the left column, and 1000 to 2000 times in the middle and right columns.

  Hereinafter, a mode (embodiment) for implementing a vacuum heat insulating material, a method for manufacturing a vacuum heat insulating material, and a refrigerator according to the present invention will be described in detail with reference to the drawings as appropriate.

[Vacuum insulation]
FIG. 1 is a schematic sectional view illustrating the configuration of the vacuum heat insulating material according to the present embodiment.
As shown in FIG. 1, the vacuum heat insulating material 1 has a core material 2 and a package 3.
(Core material)
The core material 2 is an aggregate of inorganic fibers, and a fusion layer 2a formed by fusing at least a part of the inorganic fibers is formed on the surface of the aggregate.
As the inorganic fiber, glass fiber, ceramic fiber, rock wool, or the like can be used, but is not limited thereto.
The aggregate of inorganic fibers refers to raw cotton integrally formed by intertwining innumerable inorganic fibers manufactured by an arbitrary manufacturing method. The shape of the raw cotton is preferably, for example, a sheet having a predetermined thickness, but is not limited thereto. For the aggregate of inorganic fibers, only one of the raw cottons may be used, or a plurality of the raw cottons may be used for convenience of the manufacturing method. That is, as described above, in the case of a sheet-like raw cotton, it may be a single layer or a plurality of layers.

  As the inorganic fibers, for example, those having an average fiber diameter of 2 to 6 μm can be suitably used, but those having an average fiber diameter outside this range can be used without any problem. Such an inorganic fiber can be obtained, for example, by a centrifugal method.

As described above, the fusion layer 2a is obtained by fusing at least a part of the inorganic fibers to the surface of the aggregate. That is, the fusion layer 2a is formed by fusing at least a part of the inorganic fibers under predetermined conditions, as described in a method of manufacturing the vacuum heat insulating material 1 described later. The hardness can be made harder than the inside of the core material 2. Therefore, since the vacuum heat insulating material 1 can maintain its shape firmly by having the fusion layer 2a, the dimensional accuracy can be increased when the vacuum heat insulating material 1 is formed. Moreover, the vacuum heat insulating material 1 can lower the restoration rate even when the inorganic fibers are exposed from the package 3.
The fusion layer 2a has only to have the desired effect of providing the vacuum heat insulating material 1 with high dimensional accuracy and low restoration rate, and is obtained by fusing all the regions corresponding to the fusion layer 2a. Need not be.

  The thickness of the fusion layer 2a is preferably 2 mm or less, more preferably 1 mm or less. When the thickness of the fusion layer 2a is in this range, the desired effect of providing the vacuum heat insulating material 1 having excellent heat insulating performance, high dimensional accuracy, and low restoration rate can be reliably achieved. It is more preferable that the thickness of the fusion layer 2a be 0.1 mm or more from the viewpoint of more reliably achieving the expected effect. The thickness of the fusion layer 2a can be arbitrarily adjusted by appropriately controlling the type and thickness of the inorganic fiber and the conditions of the fusion layer forming step in the method for manufacturing the vacuum heat insulating material 1 described below. Since the thickness of the fusion layer 2a can vary depending on the type of the inorganic fiber used and the like, it is preferable to confirm the conditions of the fusion layer forming step by performing a test or the like in advance.

  The fusion layer 2a is preferably in a state where the density of the inorganic fibers is high. As described above, when the density of the inorganic fibers to be fused is increased, the hardness of the surface of the core material 2 can be further increased (hardened). The density of the inorganic fibers of the fusion layer 2a can be increased by performing pressing under predetermined conditions (temperature and time) in a fusion layer forming step in a method for manufacturing the vacuum heat insulating material 1 described below.

Here, FIG. 2 is a scanning electron microscope image (SEM image) showing an example of the inorganic fiber.
As shown in FIG. 2, it is preferable that needle-like crystals 2c are formed on the surface of the inorganic fibers 2b. In this way, the inorganic fibers 2b can be prevented from sticking to each other, so that the heat conduction due to the adhesion between the inorganic fibers 2b can be suppressed.
It is preferable that the size of the needle-like crystal 2c formed on the surface of the inorganic fiber 2b be smaller than the diameter of the inorganic fiber 2b to lower the thermal conductivity.
The needle-like crystal 2c is formed of sulfur. Since the thermal conductivity of sulfur is lower than that of the inorganic fibers 2b, the thermal conductivity of the vacuum heat insulating material 1 can be further reduced.
The needle-like crystals 2c can be formed by using sulfuric acid as a dispersant when the inorganic fibers 2b are formed into a sheet by a wet papermaking method.

(Package)
The package 3 contains the core material 2 and maintains the inside in a reduced pressure state (a so-called vacuum state). That is, the package 3 forms an exterior of the vacuum heat insulating material 1.
As the package 3, a laminate film having gas barrier properties and capable of being thermally welded can be suitably used. As the laminate film, a film having a four-layer structure of a surface protective layer, a first gas barrier layer, a second gas barrier layer, and a heat welding layer can be suitably used.

The surface protective layer has a role of a protective material, and it is preferable to use a resin film having low hygroscopicity.
The first gas barrier layer is provided with a metal deposition layer on a resin film, the second gas barrier layer is provided with a metal deposition layer on a resin film having high oxygen barrier properties, and the first gas barrier layer and the second gas barrier layer are opposed to each other. It is preferable to use a material that is adhered to.
It is preferable to use a resin film having low hygroscopicity for the heat-welding layer as well as the surface protective layer.

  Specifically, it is preferable to use a resin film such as a biaxially-stretched polypropylene, polyamide, or polyethylene terephthalate as the surface protective layer. The first gas barrier layer is preferably a biaxially stretched polyethylene terephthalate film with aluminum deposition. As the second gas barrier layer, it is preferable to use a biaxially stretched ethylene vinyl alcohol copolymer resin film with aluminum deposition, a biaxially stretched polyvinyl alcohol resin film with aluminum deposition, or an aluminum foil. It is preferable to use an unstretched resin film such as polyethylene or polypropylene for the heat welding layer.

Since the vacuum heat insulating material 1 has the above-mentioned fusion layer 2a on the surface of the core material 2 and can keep the shape firmly, the core material 2 can be directly and easily attached to the package 3 having gas barrier properties. Can be included. Therefore, the vacuum heat insulating material 1 does not require the inner bag which has been used for enclosing the core material in the outer bag having gas barrier properties. Therefore, the vacuum heat insulating material 1 can reduce the cost of the operation of packing the core material in the inner bag and the cost of the inner bag, and can reduce the cost.
In the present embodiment, an inner bag may be used as necessary for the purpose of reinforcing the package 3, facilitating the handling of the core material 2, or storing the core material 2.

  The vacuum heat insulating material 1 may contain a gas adsorbent 2d such as synthetic zeolite, activated carbon, activated alumina, or silica gel inside the package 3 or in the core material 2. The gas adsorbent 2d may be present locally inside the package 3 or in the core material 2, or may be present in a dispersed state.

(Action / Effect)
As described above, the vacuum heat insulating material 1 according to the present embodiment has the above-described fusion layer 2a on the surface of a core material 2 which is an aggregate of inorganic fibers, as shown in FIG. Therefore, the vacuum heat insulating material 1 can maintain its shape firmly by having the fusion layer 2a, so that the dimensional accuracy can be increased when the vacuum heat insulating material 1 is formed. For example, since the vacuum heat insulating material 1 has the fusion layer 2a, when the end surface of the core material 1 is cut before enclosing in the package 3 or before evacuation in a vacuum sealing step described later, , The cutting accuracy can be improved. In addition, since the vacuum heat insulating material 1 has the above-described fusion layer 2a, the restoration rate can be reduced even when the inorganic fibers are exposed from the package 3.

  Furthermore, according to the vacuum heat insulating material 1, the thickness of the core material 2 can be kept thin because it has the fusion layer 2a. Therefore, the vacuum heat insulating material 1 can reduce the size of the package 3 and can reduce the cost.

[Manufacturing method of vacuum insulation material]
Next, a method for manufacturing the vacuum heat insulating material according to the present embodiment will be described.
In the description of the method for manufacturing a vacuum heat insulating material according to the present embodiment, the same reference numerals are given to components common to the above-described vacuum heat insulating material 1 according to the present embodiment, and detailed description thereof will be omitted.

  The method for manufacturing a vacuum heat insulating material according to the present embodiment includes a fusion layer forming step and a vacuum sealing step, and these steps are performed in this order.

(Fusing layer forming step)
In the fusion layer forming step, the core material 2 which is an aggregate of inorganic fibers is pressed at a temperature higher than the strain point of the inorganic fibers to form the fusion layer 2a on the surface of the aggregate (core material 2). It is a process. The “strain point” means a temperature at which the inorganic fiber starts to be distorted. In other words, if it is lower than this, it means the temperature at which the distortion of the inorganic fiber does not occur. That is, the strain point refers to a temperature at which the viscous flow of the inorganic fiber cannot practically occur. In the fusion layer forming step, by pressing at a temperature higher than the strain point of the inorganic fibers, at least a part of the inorganic fibers is melted, and the inorganic fibers can be fused to each other. Therefore, the core material 2 that has undergone this fusion layer forming step can maintain its shape firmly as described above.

  In the fusion layer forming step, since the pressing is performed at a temperature higher than the strain point of the inorganic fibers, the fusion is performed while compressing the surface of the core material 2 toward the inside of the core material 2. Therefore, the fusion layer 2a often has a state in which the density of the inorganic fibers is high. As described above, since the inorganic fibers are fused with a high density, the hardness of the surface of the core material 2 can be further increased.

The fusion layer forming step can be performed by using a mold (not shown) that has a predetermined mold and can be heated.
The heating temperature of the mold may be appropriately set according to the strain point of the inorganic fibers forming the fusion layer 2a. In the present embodiment, since the temperature higher than the strain point of the inorganic fibers is preferably 500 ° C. or higher, the heating temperature of the mold is preferably set to be higher. However, since the strain point of the inorganic fiber may be lower than 500 ° C., when such an inorganic fiber is used, the heating temperature of the mold can be appropriately changed according to the strain point of the inorganic fiber. For example, the heating temperature of the mold can be set in the range of 500 to 600 ° C. Note that the higher the heating temperature, the larger the welded portion at the fiber tip, so it is more preferable that the temperature be in the range of 500 to 550 ° C.
The heating time by the mold can be, for example, 10 to 20 minutes, but is not limited to this range as long as the fusion layer 2a can be formed. The molding load of the mold can be, for example, 0.05 to 0.5 MPa, but is not limited to this range.

  The above-mentioned strain point is determined, for example, by a method defined in the text of JIS R 3103-2: 2001 (a method of measuring a cooling point and a strain point of glass by a fiber stretching method) or annex 1 of the standard. It can be measured by a prescribed method (a method of measuring a cooling point and a strain point by a beam bending method).

(Vacuum sealing process)
The vacuum sealing step is a step of enclosing the core material 2 on which the fusion layer 2a is formed in the package 3 and sealing the package 3 while keeping the inside of the package 3 under reduced pressure. When the core material 2 is included in the package 3, the end surface of the core material 2 can be cut as necessary. At this time, as described above, since the core material 2 has the fusion layer 2a, cutting accuracy can be improved.

  The vacuum sealing step can be performed by using a vacuum chamber (not shown) to which the package 3 can be thermally welded. That is, the core material 2 is wrapped in the package 3 and placed in a vacuum chamber with a predetermined portion of the package 3 opened. Then, the pressure inside the vacuum chamber is reduced to a degree of vacuum of 1.0 Pa or less, and the inside of the vacuum chamber is evacuated. Next, a predetermined opening of the package 3 is sealed by heat welding in the vacuum chamber as it is. Thereafter, the inside of the vacuum chamber is returned to the atmospheric pressure, and the vacuum heat insulating material 1 is taken out of the vacuum chamber. Thus, the vacuum heat insulating material 1 according to the present embodiment is completed.

(Action / Effect)
According to the method for manufacturing a vacuum heat insulating material according to the present embodiment described above, the method includes the step of forming a fusion layer and the step of vacuum sealing. Therefore, the core material 2 is an aggregate of inorganic fibers, and a fusion layer 2a in which at least a part of the inorganic fibers is fused is formed on the surface of the aggregate. The vacuum heat insulating material 1 having the package 3 kept in a reduced pressure state can be manufactured. Since the vacuum heat insulating material 1 manufactured in this manner has the above-mentioned fusion layer 2a, the shape thereof can be firmly maintained. Therefore, the dimensional accuracy of the vacuum heat insulating material 1 can be increased when the vacuum heat insulating material 1 is formed. In addition, since the vacuum heat insulating material 1 has the above-described fusion layer 2a, the restoration rate can be reduced even when the inorganic fibers are exposed from the package 3. Furthermore, since the restoration rate of the vacuum heat insulating material 1 is low, a dimensional change at the time of evacuation (at the time of opening to the atmosphere) in the vacuum sealing step can be reduced. Therefore, this also contributes to increasing the dimensional accuracy of the vacuum heat insulating material 1.

[refrigerator]
Next, a refrigerator according to the present embodiment will be described with reference to FIGS.
FIG. 3 is a schematic sectional view illustrating the configuration of the refrigerator according to the present embodiment. FIG. 4 is a sectional view taken along line AA of FIG.
In the description of the refrigerator according to the present embodiment, the same reference numerals are given to the same components as those of the vacuum heat insulating material according to the present embodiment and the method of manufacturing the same, and detailed description thereof will be omitted.

  As shown in FIG. 4, the refrigerator 10 has storage rooms such as a refrigerator room 11, an ice storage room 12a, an upper freezing room 12b, a freezing room 13, and a vegetable room 14 from the top. As shown in FIG. 3, the front opening of each storage compartment is configured to be openable and closable by a door, and the refrigerator compartment doors 16a, 16b, the ice storage compartment door 17a, and the upper freezer compartment that rotate from above on the hinge 15 and the like. A door 17b, a lower freezer compartment door 18, and a vegetable compartment door 19 are arranged. Except for the refrigerator compartment doors 16a and 16b, all are drawer-type doors, and the ice storage compartment door 17a, the upper freezing compartment door 17b, the lower freezing compartment door 18, and the vegetable compartment door 19 pull out the respective doors when the doors are pulled out. In this configuration, the container to be configured is pulled out together with the door.

  The storage compartment side surface of the ice storage compartment door 17a, the upper freezing compartment door 17b, the lower freezing compartment door 18, and the vegetable compartment door 19 is provided with a packing 20 in which a permanent magnet is buried inside in order to hermetically seal with the main body of the refrigerator 10. I have. The packing 20 is mounted near the outer periphery of the storage compartment side of the ice storage compartment door 17a, the upper freezing compartment door 17b, the lower freezing compartment door 18, and the vegetable compartment door 19.

  In addition, a partitioning hot wall 21 is arranged to partition and insulate the refrigerator compartment 11 from the ice making compartment 12a and the upper freezing compartment 12b. The partitioning hot wall 21 is a heat insulating wall having a thickness of about 30 to 50 mm, and includes a vacuum heat insulating material 1 (1a) according to the present embodiment together with a heat insulating material 32 such as styrofoam or foamed heat insulating material (hard urethane foam). Made in combination.

  Because the control temperature zone is the same between the ice making room 12a and the upper freezing room 12b, and the lower freezing room 13, a partition member 22 having a receiving surface of the packing 20 is provided instead of a partition and a partition heat insulating wall for heat insulation. ing.

  A partitioning hot wall 23 is arranged to partition and insulate between the lower freezing compartment 13 and the vegetable compartment 14. The partitioning hot wall 23 is a heat insulating wall having a thickness of about 30 to 50 mm similarly to the partitioning hot wall 21, and a vacuum according to the present embodiment, together with a heat insulating material 32 such as a styrofoam or a foamed heat insulating material (hard urethane foam). It is made by combining the heat insulating material 1 (1b).

That is, the refrigerator 10 basically includes the vacuum heat insulating material 1 (1a, 1b) inside a partitioning hot wall that partitions rooms (storage rooms) having different storage temperature zones such as refrigeration and freezing.
In the refrigerator 10, the vacuum heat insulating material 1 (1c, 1d, 1e) is provided in the inside 24b of the heat insulating box 24 formed by the outer box 25 and the inner box 26.
Further, the refrigerator 10 has a storage room door (refrigeration room doors 16a, 16b) in which the vacuum heat insulating material 1 (1f) is formed by an outer plate 10a and an inner plate 10b which open and close a storage room formed in the heat insulating box 24. , An ice making room door 17a, an upper freezing room door 17b, a lower freezing room door 18, and a vegetable room door 19).
In addition, the refrigerator 10 can obtain excellent heat insulating properties by including at least one of the vacuum heat insulating materials 1 (1a to 1f) described in the above-described embodiment. It is preferable to have all of them from the viewpoint of obtaining.
The refrigerator 10 can arbitrarily insulate the respective storage rooms in the heat insulating box 24 from the outside by adopting the above-described embodiment.

Specifically, in a space between the outer box 25 and the inner box 26 (the inside 24b of the heat insulating box 24), the vacuum heat insulating materials 1 (1c, 1d, 1e) are arranged, and the vacuum heat insulating materials 1c, 1d are arranged. 1e are filled with a heat insulating material 24a such as rigid urethane foam. The vacuum heat insulating material 1c is arranged on the top side of the heat insulating box 24, the vacuum heat insulating material 1d is arranged on the back side of the heat insulating box 24, and the vacuum heat insulating material 1e is arranged on the bottom side of the heat insulating box 24. .
In addition, vacuum insulation materials 1f are arranged in the interior 10c of the storage room door formed by the outer plate 10a and the inner plate 10b that open and close each storage room formed in the heat insulating box 24, and insulate the outside from the outside. I have.

  The storage compartments of the refrigerator compartment 11, the ice making compartment 12a, the upper freezer compartment 12b, the lower freezer compartment 13, and the vegetable compartment 14 are respectively formed from above in the heat insulating box 24 constituting the main body of the refrigerator 10. However, the arrangement of each storage room is not particularly limited to this. The refrigerator doors 16a and 16b, the ice making door 17a, the upper freezing compartment door 17b, the lower freezing compartment door 18, and the vegetable compartment door 19 are also particularly limited in terms of opening / closing by rotation, opening / closing by drawer, and the number of door divisions. is not.

  Further, a cooler is provided on the back side of the lower freezing compartment 13 to cool each of the refrigerator compartment 11, the ice making compartment 12a, the upper freezing compartment 12b, the lower freezing compartment 13, and the vegetable compartment 14 of the refrigerator 10 to a predetermined temperature. 28 are provided. In the cooler 28, a compressor 29 and a condenser 30 and a capillary tube (not shown) are connected to form a refrigeration cycle.

  Above the cooler 28, a blower 31 for circulating the cool air cooled by the cooler 28 in the refrigerator and maintaining a predetermined low temperature is provided.

  A storage recess 34 for storing an electric component 33 such as a board for controlling the operation of the refrigerator 10 and a power supply board is formed in a rear portion of a top surface of the heat insulating box 24. Is provided.

  The height of the cover 35 is arranged so as to be substantially the same as the top surface of the outer box 25 in consideration of the appearance design and securing the internal volume. Although not particularly limited, when the height of the cover 35 is higher than the top surface of the outer box, it is desirable that the height be within 10 mm.

  Along with this, the storage concave portion 34 is arranged in the heat insulating material 24a side so as to be recessed only in the space for storing the electric component 33, so that the internal volume is necessarily sacrificed in order to secure the heat insulating thickness. Conversely, if the inner volume is made larger, the thickness of the heat insulating material 24a between the storage recess 34 and the inner box 26 becomes thinner, and the heat insulation performance is reduced. Therefore, as shown in FIG. It is preferable to arrange the vacuum heat insulating material 1c in the heat insulating material 24a to secure and enhance the heat insulating performance.

  In the present embodiment, the vacuum heat insulating material 1 c is formed into a substantially Z shape so as to straddle the case (not shown) of the interior lamp provided on the upper part (the ceiling part) of the inner box 26 and the electric component 33. I have. The cover 35 is made of a steel plate in consideration of heat resistance. Further, since the compressor 29 and the condenser 30 arranged at the lower rear part of the heat insulating box 24 are components that generate a large amount of heat, a projection surface to the inner box 26 side to prevent heat from entering the inside of the refrigerator. Is provided with a vacuum heat insulating material 1e.

(Action / Effect)
The refrigerator 10 according to the present embodiment described above includes the inside 24b of the heat insulating box 24 formed by the outer box 25 and the inner box 26, and the outer plate 10a that opens and closes the storage room formed in the heat insulating box 24. The vacuum according to the present embodiment described above is provided in at least one of the inside 10c of the storage room door formed by the inner plate 10b and the inside of the partitioning hot wall separating the rooms (storage rooms) having different storage temperature zones. A heat insulating material 1 is provided. Since the vacuum heat insulating material 1 has the fusion layer 2a, not only the dimensional accuracy is high and the restoration rate is low, but also the thickness of the core material 2 can be kept thin. Therefore, the size of the package 3 for packaging the vacuum heat insulating material 1 can be reduced, and the inner bag is not required, so that the cost of the refrigerator 10 including the same can be reduced. Further, in the refrigerator 10, even when the vacuum heat insulating material 1 is exposed due to the breakage of the package 3 or the like, since the restoration rate of the inorganic fibers is low, phenomena such as deformation of the inner box 26 hardly occur. In addition, the handling, processing and storage of inorganic fibers can be facilitated.

Next, the effect of the vacuum heat insulating material was confirmed by an example, and will be described below.
An inorganic fiber (B ₂ O ₃ less than 5%, strain point 498 ° C.) having a width of 300 mm, a length of 570 mm and a height of about 150 mm (basis weight 4200 g / m ² ) was prepared. The height is a target value, and the actual height of the inorganic fibers used in the test is as shown in “Initial thickness” in Table 1.
Then, as shown in Table 1 and FIG. 5, pressing (forming pressure: 0.1 MPa) was performed at a temperature of 400 to 600 ° C. for 10 minutes, respectively. FIG. 5 is a graph showing the amount of restoration of the thickness of the core material when pressed at each pressing temperature for 10 minutes.

The thickness of each inorganic fiber before pressing (initial thickness), the thickness immediately after pressing, and the thickness three days after pressing were measured. These are described as “initial thickness”, “immediately after pressing”, and “after 3 days” in Table 1 and FIG. 5, respectively. Note that the restoration rate can be calculated from the amount of increase from the thickness immediately after pressing to the thickness three days later from the following equation (1).
Restoration rate (%) = {(thickness after 3 days / thickness immediately after pressing) −1} × 100 Formula (1)

As shown in Table 1 and FIG. 5, by pressing at 400 ° C. or 480 ° C. for 10 minutes, the thickness immediately after pressing can be reduced, but when left (after 3 days), the thickness of the core material is greatly restored. It was confirmed that it would.
By pressing at 500 ° C. or more × 10 minutes or more, it was confirmed that the thickness of the core material could be reduced and the restoration amount (restoration rate) was small. In particular, it was confirmed that when the pressing temperature was 520 ° C. or higher, the restoration amount (restoration rate) became smaller.

  Scanning electron microscope images of those processed at 400 ° C. × 10 minutes, 480 ° C. × 10 minutes, 500 ° C. × 10 minutes, and 600 ° C. × 10 minutes were taken from those shown in Table 1. In addition, a scanning electron microscope image of the sample processed at 480 ° C. × 5 minutes (equivalent to the example of Patent Document 1) was taken. The image is shown in FIG.

  As shown in FIGS. 6B to 6E, in the inorganic fibers used this time, when pressed at a temperature of 480 ° C. or lower, it was confirmed that the inorganic fibers adhered to each other by heat during spinning were intact. That is, in these cases, since the pressing temperature was low and the strain point of the inorganic fibers did not reach, it was confirmed that the inorganic fibers adhered to each other were not peeled off by the heat during spinning. Further, since the pressing temperature was lower than the strain point, the inorganic fibers did not fuse with each other, and a fused layer could not be formed. For this reason, as described above, the thickness immediately after pressing can be reduced, but it is considered that the thickness of the core material has been largely restored when left (after 3 days).

On the other hand, as shown in F and G in FIG. 6, when pressed at a temperature of 500 ° C. or more, it was confirmed that the fibers adhered to each other were peeled off by the heat during spinning. That is, in these cases, since the pressing temperature was high and the strain point of the inorganic fibers was reached, it was confirmed that the inorganic fibers adhered to each other were peeled off by the heat during spinning. In addition, when the inorganic fibers attached to each other are peeled off by the heat during spinning, a space is formed in the inorganic fibers, so that heat conduction due to the close contact between the inorganic fibers can be suppressed. In addition, since the pressing temperature was equal to or higher than the strain point, at least a part of the inorganic fibers was fused (see H in FIG. 6), and a fused layer was formed. It was confirmed that these inorganic fibers had a fused layer formed and their shapes were firmly maintained. Therefore, it is considered that the dimensional accuracy can be increased in the case of forming a vacuum heat insulating material or the like. Further, it was confirmed that the vacuum heat insulating material using the inorganic fiber (core material) can reduce the restoration rate even when the inorganic fiber is exposed from the package.
In addition, as shown in Table 1, since the temperature (center temperature after pressing) of the inorganic fiber at the substantially middle position in the thickness direction was lower than the strain point in all the examples, the inside of the core material was fused. I didn't. In this manner, when the core material is not fused to the inside, the porosity is high, so that a higher heat insulating property can be obtained.

  From these results, by pressing the aggregate of inorganic fibers at or above the strain point of the inorganic fibers, it is possible to obtain a core material having a fusion layer formed on the surface, and enclose this in a package. It was found that a vacuum heat insulating material was obtained by keeping the inside in a reduced pressure state (vacuum state). Further, it has been found that this vacuum heat insulating material can be applied to a refrigerator as well as a known vacuum heat insulating material.

  As described above, the vacuum heat insulating material, the method for manufacturing the vacuum heat insulating material, and the refrigerator according to the present invention have been described in detail with the embodiments. However, the present invention is not limited to the above embodiments, and includes various modifications. . For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described above. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment. Further, for a part of the configuration of each embodiment, it is possible to add, delete, or replace another configuration.

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2 Core material 2a Fused layer 2b Inorganic fiber 2c Needle-shaped crystal 3 Package 10 Refrigerator 24 Insulated box 25 Outer box 26 Inner box 10a Outer plate 10b Inner plate

Claims (6)

A core material which is an aggregate of inorganic fibers, and a fusion layer formed by fusing at least a part of the inorganic fibers to the surface of the aggregate,
Together enclosing the core member, the interior is closed and a packaging body is kept in a reduced pressure state,
The thickness of the fusion layer is 0.1 mm or more and 2 mm or less,
The temperature after pressing at the intermediate position in the thickness direction of the inorganic fiber is lower than the strain point,
The thickness of the inorganic fiber before pressing is 120 mm or more,
From the thickness of the inorganic fiber immediately after pressing and the thickness three days after pressing, the restoration rate calculated by {(thickness after three days / thickness immediately after pressing) -1} × 100 is 25% or less.
Vacuum heat insulating material, characterized in that it. Oite to claim 1,
A vacuum heat insulating material, wherein needle-like crystals are formed on the surface of the inorganic fiber. In claim 2 ,
The vacuum heat insulating material, wherein the needle-like crystals contain sulfur. A core material that is an aggregate of inorganic fibers is pressed at a temperature higher than the strain point of the inorganic fibers to form a fusion layer in which at least a portion of the inorganic fibers is fused to the surface of the aggregate. A layer forming step;
The fusion adhesive layer of the formed core material is contained in the packaging body, have a, a vacuum sealing step of sealing with the inside of the package in a reduced pressure state,
In the fusing layer forming step, while the thickness of the fusing layer is 0.1 mm or more and 2 mm or less, the temperature after pressing at the intermediate position in the thickness direction of the inorganic fiber is lower than the strain point,
The thickness of the inorganic fibers before pressing in the fusion layer forming step is 120 mm or more,
From the thickness of the inorganic fiber immediately after pressing and the thickness three days after pressing, the restoration rate calculated by {(thickness after three days / thickness immediately after pressing) -1} × 100 is 25% or less. A method for producing a vacuum heat insulating material, comprising: In claim 4 ,
A method for producing a vacuum heat insulating material, wherein a temperature higher than a strain point of the inorganic fiber in the fusion layer forming step is 500 ° C. or more. A core material in which a fusion layer formed by fusing at least a part of the inorganic fiber to the surface of the aggregation is formed of an inorganic fiber, and the core material is included therein, and the inside thereof is in a reduced pressure state. A vacuum heat insulating material having a package held in the inside of a heat insulating box formed by an outer box and an inner box, and an outer plate for opening and closing a storage room formed in the heat insulating box. Provided in at least one of the inside of the storage room door formed by the plate and the inside of the partitioning heat wall that partitions the rooms having different storage temperature zones ,
The thickness of the fusion layer is 0.1 mm or more and 2 mm or less,
The temperature after pressing at the intermediate position in the thickness direction of the inorganic fiber is lower than the strain point,
The thickness of the inorganic fiber before pressing is 120 mm or more,
From the thickness of the inorganic fiber immediately after pressing and the thickness three days after pressing, the restoration rate calculated by {(thickness after three days / thickness immediately after pressing) -1} × 100 is 25% or less.
Refrigerator characterized by Der Rukoto.