JP5380313B2 - Vacuum heat insulating material and refrigerator using the same - Google Patents

Description

  The present invention relates to a vacuum heat insulating material and a refrigerator to which the vacuum heat insulating material is applied.

  In recent electric products, particularly household appliances related to cold heat, vacuum insulation is used to improve heat insulation performance from the viewpoint of reducing power consumption.

  Conventional examples of the vacuum heat insulating material include those described in Patent Document 1 and Patent Document 2. Patent Document 1 describes a glass wool that is a glass fiber as a core material, covered with a gas barrier outer covering material, and the inside is in a reduced pressure state. In addition, the core material is formed by press-pressing at a high temperature at which the glass fiber starts to be thermally deformed so as to have a constant thickness.

  Patent Document 2 describes a sheet-like fiber aggregate containing 50% by weight or more of a polyester fiber having a fiber thickness of 1 to 6 denier in consideration of recyclability as a core material.

Japanese Patent Laid-Open No. 2005-220954 JP 2006-29505 A

  However, in the configuration described in Patent Document 1, the amount of heat energy consumed in the manufacturing process of the core material is enormous, and there are problems in terms of cost performance and environmental considerations.

  Moreover, in the structure of patent document 2, the sheet-like process was given by the needle punch method, and as a result of having bundled polyester fiber, heat conduction became easy and the subject that heat insulation performance was inferior occurred.

  That is, it is difficult for conventional vacuum heat insulating materials to satisfy both energy consumption, productivity, and heat insulating performance at the time of manufacture, and both have advantages and disadvantages.

  Accordingly, in view of the above problems, the present invention provides a vacuum heat insulating material that suppresses energy consumption during the manufacture of a vacuum heat insulating material, has a low environmental load, has excellent heat insulating performance and productivity, and a refrigerator using the same. It is.

In order to achieve the above object, a vacuum heat insulating material of the present invention comprises a core material containing organic fibers and a jacket material that houses the core material, and the vacuum heat insulating material that seals the inside of the jacket material under reduced pressure. The organic fiber contains an organic peroxide additive as an additive for improving fluidity.

  The additive is added in an amount of 0.2 wt% to 1.8 wt%.

  The organic peroxide additive is bis (tertiary butyldioxyisopropyl) benzene.

Moreover, the organic fibers is characterized in that it is a polystyrene resin fibers.

Further, the refrigerator of the present invention comprises an outer box forming a box, an inner box provided inside the outer box, and a vacuum heat insulating material provided between the outer box and the inner box. In the refrigerator having, the vacuum heat insulating material includes a core material containing an organic fiber and a jacket material containing the core material, and the inside of the jacket material is sealed under reduced pressure, and the organic fiber is fluid. It is characterized by containing an organic peroxide additive as an additive for improving the viscosity.

  ADVANTAGE OF THE INVENTION According to this invention, the energy consumption at the time of vacuum heat insulating material manufacture is suppressed, an environmental load is small, and the vacuum heat insulating material excellent in heat insulation performance and productivity, and a refrigerator using this can be provided.

Sectional drawing of the conventional vacuum heat insulating material. Sectional drawing which shows the use condition of the vacuum heat insulating material regarding embodiment of this invention. The front view of the refrigerator regarding embodiment of this invention. AA sectional drawing of FIG. The parameter table | surface of the prior art example of this invention, an Example, and a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a conventional vacuum heat insulating material. FIG. 2 is a cross-sectional view showing a usage state of the vacuum heat insulating material according to the embodiment of the present invention. FIG. 3 is a front view of the refrigerator according to the embodiment of the present invention. 4 is a cross-sectional view taken along the line AA in FIG.

(Conventional example)
First, a conventional example will be described with reference to FIG. The vacuum heat insulating material 101 includes an outer covering material 102, an inner bag 103, a core material 104, and an adsorbent (not shown).

  The outer covering material 102 is a laminated film composed of four layers: a surface layer, a moisture-proof layer, a gas barrier layer, and a heat welding layer. Specifically, the surface layer is a polypropylene film having low hygroscopicity. For the moisture-proof layer, an aluminum vapor deposition layer is provided on a polyethylene terephthalate film. The gas barrier layer is provided by depositing an aluminum vapor deposition layer on an ethylene vinyl alcohol copolymer film so as to face the aluminum vapor deposition layer of the moisture-proof layer. The heat-welded layer uses a highly versatile linear low density polyethylene film. Each layer is bonded by a dry laminating method through a two-component curable urethane adhesive.

  For the inner bag 103, a heat-weldable polyethylene film is used. As the adsorbent, a physical adsorption type synthetic zeolite is used.

  As the core material 104, a fiber assembly in which polystyrene resin is fiberized is used. At this time, the melt flow rate (MFR) of the polystyrene resin is 3 g / 10 min.

  The fiber aggregate is obtained by melting a polystyrene resin at 290 ° C. and fiberizing it by a melt blown method, and has an average fiber diameter of 11 to 15 μm. Further, the flexural modulus at this time is 3300 MPa.

  In this configuration, after the dried core material 104 is covered with the inner bag 103, it is compressed into a sealed state, and after inserting it into the outer cover material 102, one end of the inner bag 104 is opened to release the seal. To set in a vacuum packaging machine. Thereafter, the pressure is reduced from atmospheric pressure to a vacuum degree of 2.2 Pa at a stretch, and after holding for a certain period of time at a vacuum degree of 2.2 Pa or less, the jacket material 53 is sealed. The value obtained by measuring the thermal conductivity of the vacuum heat insulating material thus obtained with a thermal conductivity measuring device Auto λHC-074 manufactured by Eihiro Seiki Co., Ltd. is defined as 100. The thermal conductivity will be described later in comparison with the following examples.

  The conventional example and the following Examples 1 to 6 and the comparative example are collectively shown in FIG.

Example 1
Next, Example 1 will be described with reference to FIG. The vacuum heat insulating material 50 includes an outer jacket material 53, an inner bag 54, a core material 51, and an adsorbent (not shown).

  The outer covering material 53 is not particularly limited as long as it has gas barrier properties. In Example 1, the outer covering material 53 is a laminate film composed of four layers of a surface layer, a moisture barrier layer, a gas barrier layer, and a heat welding layer.

  Specifically, the surface layer is a polypropylene film having low hygroscopicity. In addition, you may use a polyamide film, a polyethylene terephthalate film, etc. which are excellent in the puncture strength for a surface layer.

  For the moisture-proof layer, an aluminum vapor deposition layer is provided on a polyethylene terephthalate film. The gas barrier layer is provided by depositing an aluminum vapor deposition layer on an ethylene vinyl alcohol copolymer film so as to face the aluminum vapor deposition layer of the moisture-proof layer.

  The heat-welded layer uses a highly versatile linear low density polyethylene film. The heat-welding layer is not particularly limited, and any heat-welding film such as high-density polyethylene, polypropylene, or polybutylene terephthalate may be used.

  The laminate structure of the jacket material 53 is not particularly limited to the four-layer structure as long as it has the above-described characteristics, and may be five layers or three layers.

  Each layer is bonded by a dry laminating method via a two-component curable urethane adhesive, but the adhesive and the bonding method are not particularly limited thereto.

  The inner bag 54 uses a polyethylene film that can be heat-welded in the first embodiment. As the adsorbent, a physical adsorption type synthetic zeolite is used.

  The inner bag 54 and the adsorbent are not limited to these. The inner bag 54 may be a polypropylene film, a polyethylene terephthalate film, a polybutylene terephthalate film, or the like that has a low hygroscopic property and can be thermally welded and has a small outgas.

  If the adsorbent adsorbs moisture or gas, a physical adsorption type such as synthetic zeolite or silica gel having a different pore diameter, or a chemical reaction type adsorption type such as calcium oxide, calcium chloride, or strontium oxide may be used. it can.

  For the core material 51, 0.2% by weight of polystyrene resin is added to the polystyrene resin, which is an organic peroxide, bis (tertiary-butyldioxyisopropyl) benzene (trade name: Bisbreak C, manufactured by Kayaku Akzo). Then, fiberized fiber aggregates are used. An organic peroxide is a material for improving fluidity. The MFR (melt flow rate) of the polystyrene resin at this time is 6 g / 10 min.

  The fiber aggregate of the core material 51 is obtained by blending 0.2% by weight of an organic peroxide additive in polystyrene resin and thoroughly stirring with a tumbler, melting it at 290 ° C. with an extruder, The fiber diameter is 9 to 10 μm on average. Further, the flexural modulus at this time was 3280 MPa.

  As for the blended organic peroxide, in addition to bis (tertiary-butyldioxyisopropyl) benzene, benzoyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) ) Hexane, 1,1'-di-t-butylperoxy-3,3,5-trimethylenecyclohexane, 1,3-di- (t-butylperoxy) -diisopropylbenzene and the like.

  Of course, virgin materials can be used for polystyrene resins, but recycled materials recovered from waste home appliances and other used products can also be used. As the recycled material, a material that is preferably selected and washed after coarse pulverization is preferably in the form of pellets or finely pulverized to about 5 mm or less, but is not particularly limited thereto. Moreover, about the structure of a polystyrene resin, the thing of a syndiotactic structure and an isotactic structure can also be used.

  With this configuration, the core material 51 is sufficiently dried at 70 to 90 ° C., covered with the inner bag 54, compressed to be sealed, inserted into the outer jacket material 53, and then one end of the inner bag is opened. Release the seal and set it in the vacuum packaging machine. Thereafter, the pressure is reduced from atmospheric pressure to a vacuum degree of 2.2 Pa at a stretch, and after holding for a certain period of time at a vacuum degree of 2.2 Pa or less, the jacket material 53 is sealed.

  In addition, although the sealing release method of the inner bag 54 is performed by a cutter, a squeeze or the like, it is not particularly specified. As a result, when the thermal conductivity of the obtained vacuum heat insulating material was measured with a thermal conductivity measuring device Auto λHC-074 manufactured by Eihiro Seiki Co., Ltd., the ratio compared with the previous example was 98, and the heat insulating performance was improved. ing.

(Example 2)
Next, the difference between Example 2 and Example 1 is that the blending amount of the organic peroxide added to the polystyrene resin is 0.5% by weight, and the fiberized fiber assembly is used as the core material 51. is there. The rest is the same as in the first embodiment.

  In addition, the melt flow rate (MFR) of polystyrene resin is 8 g / 10min, and the fiber diameter produced by the melt blown method is an average of 8-10 micrometers. Further, the flexural modulus at this time is 3250 MPa.

  With this configuration, the fiber aggregate of the core material 51 is sufficiently dried at 70 to 90 ° C. After covering this fiber assembly with the inner bag 54, one end is compressed to be in a sealed state, inserted into the jacket material 53, and then the inner bag 54 is unsealed and set in a vacuum packaging machine. The reason for releasing the sealing of the inner bag 54 is to depressurize the inside of the inner bag 54. After that, the pressure is reduced from atmospheric pressure to a vacuum degree of 2.2 Pa at a stroke, and after holding for a certain period of time at a vacuum degree of 2.2 Pa or less, the jacket material 53 is sealed. The heat conductivity of the vacuum heat insulating material obtained by this becomes 97 by the ratio compared with the previous prior art example, and heat insulation performance improves further.

(Example 3)
Next, Example 3 is different from Examples 1 and 2 in that the compounding amount of the organic peroxide added to the polystyrene resin is 0.8% by weight, and the fiberized fiber assembly is used as the core material 51. Is a point. The rest is the same as in the first embodiment.

  In addition, the MFR of polystyrene resin is 10 g / 10 min, and the fiber diameter produced by the melt blown method is 7-9 μm on average. Further, the flexural modulus at this time is 3200 MPa.

  The heat conductivity of the vacuum heat insulating material obtained with this configuration is 95 in comparison with the previous conventional example, and the heat insulating performance is further improved.

Example 4
Next, Example 4 differs from Examples 1 to 3 in that the compounding amount of the organic peroxide added to the polystyrene resin is 1.0% by weight, and the fiberized fiber assembly is used as the core material 51. Is a point. The rest is the same as in the first embodiment.

  The MFR of the polystyrene resin is 12 g / 10 min, and the fiber diameter produced by the melt blown method is 7-9 μm on average. Further, the flexural modulus at this time is 3160 MPa.

  The heat conductivity of the vacuum heat insulating material obtained by this structure is 96 in a ratio compared with the previous conventional example.

(Example 5)
Next, Example 5 differs from Examples 1 to 4 in that the blending amount of the organic peroxide added to the polystyrene resin is 1.5% by weight, and the fiberized fiber assembly is used as the core material 51. Is a point. The rest is the same as in the first embodiment.

  In addition, the MFR of polystyrene resin is 13 g / 10 min, and the fiber diameter produced by the melt blown method is 6 to 8 μm on average. Further, the flexural modulus at this time is 3090 MPa.

  The thermal conductivity of the vacuum heat insulating material obtained with this configuration is 97 in a ratio compared to the previous conventional example.

(Example 6)
Next, with respect to Example 6, the difference from Examples 1 to 5 is that the compounding amount of the organic peroxide added to the polystyrene resin is 1.8% by weight, and the fiberized fiber assembly is used as the core material 51. Is a point. The rest is the same as in the first embodiment.

  In addition, the MFR of polystyrene resin is 13 g / 10 min, and the fiber diameter produced by the melt blown method is 6 to 8 μm on average. Further, the flexural modulus at this time is 3060 MPa.

  The heat conductivity of the vacuum heat insulating material obtained by this structure is 98 in a ratio compared with the previous conventional example.

(Comparative example)
Next, with respect to the comparative example, the difference from Examples 1 to 6 is that the blending amount of the organic peroxide added to the polystyrene resin is 2.0% by weight, and the fiberized fiber aggregate is used as the core material 51. It is.

  The MFR of polystyrene resin is 13 g / 10 min, and the fiber diameter produced by the melt blown method is 8 to 10 μm on average. Moreover, the bending elastic modulus at this time is 2950 MPa.

  The thermal conductivity of the vacuum heat insulating material obtained with this configuration is 101 in comparison with the previous conventional example, and the heat insulating performance is the same as that of the conventional example.

(Example 7)
Next, the Example which applied the vacuum heat insulating material in any one of Examples 1-6 to the refrigerator is demonstrated. 3 and 4, the refrigerator 1 includes a refrigerator room 2, an ice making room 3 a, an upper freezer room 3 b, a lower freezer room 4, and a vegetable room 5 from the top. The front opening of each storage room is provided with a closing door.

  At the front opening of the refrigerator compartment 2, rotary refrigerator compartment doors 6a and 6b that rotate around the hinge 10 and the like are provided. Except for the refrigerator compartment doors 6a and 6b, all are drawer type doors, and an ice making compartment door 7a, an upper freezer compartment door 7b, a lower freezer compartment door 8 and a vegetable compartment door 9 are provided so as to be freely drawn out. When these drawer doors are pulled out, the storage containers in the respective storage chambers are pulled out together. Moreover, the packing 11 for closely_contact | adhering and closing with the front opening of each store room is provided in the indoor side outer periphery of each door.

  In addition, a heat insulating partition 12 is disposed to partition and insulate between the refrigerator compartment 2, the ice making chamber 3a, and the upper freezer compartment 3b. The heat insulating partition 12 is a heat insulating wall having a thickness of about 30 to 50 mm, and is configured by using a single material or a combination of a plurality of heat insulating materials such as styrofoam, foam heat insulating material (urethane foam), and vacuum heat insulating material.

  Since the temperature zones are the same between the ice making chamber 3a and the upper freezing chamber 3b and the lower freezing chamber 4, a partition member 13 having a packing 11 receiving surface is provided instead of a partition heat insulating wall for partition heat insulation.

  Between the lower freezer compartment 4 and the vegetable compartment 5, a heat insulating partition 14 is provided to insulate the compartment, and in the same manner as the heat insulating partition 12, a heat insulating wall of about 30 to 50 mm is made of styrofoam or foam heat insulating material (urethane). Foam), vacuum heat insulating material, and the like. Thus, the heat insulation partitions 12 and 14 are installed in the partition between the storage rooms in which temperature zones differ.

  In addition, although the storage room of the refrigerator compartment 2, the ice-making room 3a, the upper stage freezer room 3b, the lower stage freezer room 4, and the vegetable room 5 is divided and formed in the box 20, respectively, about arrangement | positioning of each store room Is not particularly limited to this. Further, the refrigerator doors 6a and 6b, the ice making door 7a, the upper freezer door 7b, the lower freezer door 8, and the vegetable door 9 are also particularly limited in terms of opening and closing by rotation, opening and closing by drawers, and the number of divided doors. is not.

  The box 20 includes an outer box 21 and an inner box 22, and a heat insulating part is provided in a space formed by the outer box 21 and the inner box 22 to insulate each storage chamber in the box 20 from the outside. Yes. A vacuum heat insulating material 50 is disposed on either the outer box 21 side or the inner box 22 side, and a space other than the vacuum heat insulating material 50 is filled with a foam heat insulating material 23 such as rigid urethane foam.

  In addition, in order to cool each storage room of the refrigerator 1 to a predetermined temperature, a cooler 28 is provided on the back side of the lower freezing room 4, and this cooler 28, a compressor 30, a condenser 30a, illustrated in the figure. A refrigeration cycle is configured by connecting a capillary tube that does not. Above the cooler 28, a blower 27 that circulates the cool air cooled by the cooler 28 into each storage chamber and maintains a predetermined low temperature is disposed.

  In addition, an interior lamp 45 having a case 45a protruding toward the heat insulating material 23 is disposed on a part of the top surface of the inner box 22, and the storage space is brightly illuminated when the refrigerator doors 6a and 6b are opened, Visibility is improved. The interior lamp 45 is not particularly limited, such as a light bulb, a fluorescent lamp, an LED, or a xenon lamp.

  Moreover, since the thickness of the heat insulating material 23 between the case 45a and the outer box 21 becomes thin by arrangement | positioning of the interior lamp 45, the vacuum heat insulating material 50a is arrange | positioned and the heat insulation performance is ensured. The interior light 45 is not particularly defined to be disposed at the illustrated position, and may be the side surface or the back wall of the refrigerator compartment 2.

  Moreover, the recessed part 40 for accommodating electrical components 41, such as a board | substrate for controlling the driving | operation of the refrigerator 1, and a power supply board, is formed in the top surface rear part of the box 20. As shown in FIG. A cover 42 that covers the electrical component 41 is provided.

  The cover 42 is arranged so that the height of the cover 42 is substantially the same as the top surface of the outer box 21 in consideration of design properties and securing the internal volume. Although it does not specifically limit, when the height of the cover 42 protrudes from the top | upper surface of the outer case 21, it is desirable to set it in the range within 10 mm. Along with this, the recess 40 is disposed in a depressed state by the space for housing the electrical component 41 on the heat insulating material 23 side. Therefore, the internal volume is inevitably sacrificed in order to ensure the heat insulation thickness. If the internal volume is increased, the thickness of the heat insulating material 23 between the recess 40 and the inner box 22 will be reduced. For this reason, the vacuum heat insulating material 50 is arrange | positioned in the surface at the side of the heat insulating material 23 of the recessed part 40, and the heat insulation performance is ensured.

  In this embodiment, the vacuum heat insulating material 50 is a single vacuum heat insulating material 50 formed in a substantially Z shape so as to straddle the case 45a of the interior lamp 45 and the electrical component 41. The cover 42 is made of a steel plate in consideration of fire resistance.

  In addition, since the compressor 30 and the condenser 31 arranged at the lower back of the box 20 are components that generate a large amount of heat, the projection surface on the inner box 22 side is used to prevent heat from entering each storage chamber. A vacuum heat insulating material 50 is disposed.

  In addition, in order to increase the covering area of the vacuum heat insulating material 50, it is possible to form a three-dimensional shape integrally formed from the bottom surface of the inner box 22 to between the compressor 30 and the cooler 28. In addition, about the shape of the vacuum heat insulating material 50 located between the compressor 30 and the cooler 28, the notch for escaping the drain pipe which is not shown in figure is provided. The presence or absence of a notch or its shape is not particularly limited.

The vacuum heat insulating material 50 in this embodiment is any one of the first to sixth embodiments, in which the core material 51 has a thickness of 10 mm and the density of the fiber assembly is set to about 250 (kg / m ³ ). To do. By disposing the vacuum heat insulating material 50 on the top surface portion, it is possible to reduce the heat intrusion into the cabinet by the electric component 41 and the heat radiating pipe 60, further improve the heat dissipation characteristics of the heat radiating pipe 60, By arrangement | positioning, the penetration | invasion into the warehouse of the heat | fever which generate | occur | produces from the compressor 30 and the condenser 31 can be suppressed. Therefore, the heat insulation performance can be improved without increasing the wall thickness.

  The vacuum heat insulating material according to each embodiment of the present invention described above can provide an environmentally friendly vacuum heat insulating material with improved productivity and reduced energy consumption in the manufacturing process.

  In order to improve the performance of the vacuum heat insulating material, it is preferable that the resin fibers constituting the core material have high rigidity. Therefore, even if it is the same general-purpose resin, the heat insulation performance (thermal conductivity) when used as the core material of vacuum heat insulating material is higher than that when glass wool is used as the core material in the rigidity of resins such as polypropylene and polyethylene terephthalate. It was inferior. Highly rigid resins generally have a high molecular weight and therefore have poor fluidity (for example, melt flow rate). When a resin having poor fluidity is used, the resin discharge amount decreases in the resin melt extrusion with an extruder and the spinning process with the melt blown method, and thus the productivity tends to decrease. However, since the fluidity is correlated with the molecular weight of the resin, it is difficult to significantly improve the physical properties without improving the resin. Therefore, in order to solve this problem, a means to lower the molecular weight and lower the fluidity is effective. By adding a peroxide additive to break the terminal molecular chain, the molecular weight is lowered and the fluidity is improved. Is. As the molecular weight decreases, the rigidity tends to decrease, and the fluidity and rigidity are in a trade-off relationship. For this reason, there exists the optimal compounding quantity of a peroxide additive, and it implement | achieves by said each Example.

  Further, by improving the resin fluidity, the stretchability at the time of spinning is also improved, so that ultrafine fibers can be formed. By reducing the diameter of the fiber, the porosity inside the vacuum heat insulating material is improved, so that the thermal conductivity is generally reduced and the heat insulating performance is improved.

  In addition, recycled materials can be used for polystyrene resins, which not only saves energy in the raw material manufacturing process, but also greatly contributes to resource saving, and can greatly reduce the environmental burden.

  In addition, the heat insulation performance can be improved by applying the vacuum heat insulating material of the present embodiment to a high temperature bath, a thermostatic bath, etc., in general cooling equipment, houses / buildings, vehicles such as automobiles and trains, etc. in addition to the refrigerator. it can.

  Moreover, the refrigerator which concerns on embodiment of this invention can reduce environmental impact in the whole life cycle of a product by using the vacuum heat insulating material of each embodiment.

  In addition, by using a resin fiber material as a part of the core material, it is possible to greatly reduce the electrical and thermal energy consumed in the vacuum heat insulating material and the manufacturing process of the material. Furthermore, conventionally, the vacuum heat insulating material using the resin fiber material as the core material was inferior to the glass wool core material in heat insulation performance, but according to each embodiment of the present invention, the vacuum heat insulating material of the glass wool core material. Insulation performance equivalent to or better than Furthermore, since the recycled resin collected from waste home appliances can be used as the resin material, a highly recyclable vacuum heat insulating material and refrigerator can be provided.

DESCRIPTION OF SYMBOLS 1 Refrigerator 12, 14 Heat insulation partition 20 Box 21 Outer box 22 Inner box 23 Heat insulating material 33 Foam polystyrene 40 Recess 41 Electrical component 42 Cover 45 Interior light 45a Case 50 Vacuum heat insulating material 51 Core material 53 Outer material 54 Inner bag

Claims (5)

In a vacuum heat insulating material comprising a core material containing organic fibers, and a jacket material containing the core material, and sealing the inside of the jacket material under reduced pressure,
The said organic fiber contains an organic peroxide additive as an additive which improves fluidity | liquidity, The vacuum heat insulating material characterized by the above-mentioned.   The vacuum heat insulating material according to claim 1, wherein the additive is added in an amount of 0.2 wt% to 1.8 wt%.   3. The vacuum heat insulating material according to claim 1, wherein the organic peroxide additive is bis (tertiary butyldioxyisopropyl) benzene. The organic fibers are vacuum heat insulating material according to any one of claims 1 to 3, wherein the polystyrene resin fibers. In a refrigerator having an outer box that forms a box, an inner box provided inside the outer box, and a vacuum heat insulating material provided between the outer box and the inner box,
The vacuum heat insulating material includes a core material containing an organic fiber and a jacket material containing the core material, and the inside of the jacket material is sealed under reduced pressure, and the organic fiber is added to improve fluidity. A refrigerator comprising an organic peroxide additive as an agent.

Images