Vacuum insulation and refrigerators

Abstract

The present invention provides a vacuum insulation material that can suppress the deterioration of insulation performance caused by organic gases derived from the outer packaging material, and a refrigerator equipped with the same. [Solution] The vacuum insulation material 100 comprises an outer packaging material 101 having gas barrier properties, a core material 102 filled inside the outer packaging material 101, and an adsorbent 103 contained inside the outer packaging material 101, wherein the adsorbent 103 has a specific surface area of ​​500 m² 2 The material is mesoporous with well-developed mesopores having a density of 1 / g or more and a diameter of 2 nm or more and less than 50 nm, and contains a gas adsorbent capable of adsorbing organic gases originating from the outer packaging material 101 (e.g., decane, dodecane, tetradecane, hexadecane, octadecane, eicosane, etc. released by the heat-sealed layer of the outer packaging material 101). The refrigerator is equipped with a vacuum insulation material 100.

Description

[Technical Field]

[0001] The present invention relates to a vacuum insulation material containing an adsorbent, and a refrigerator equipped therewith. [Background technology]

[0002] In recent years, from the perspective of reducing carbon dioxide emissions and conserving energy, there has been a demand for reducing power consumption not only in commercial electrical appliances but also in household ones. For example, the power consumption of refrigerators can be reduced by improving the insulation between the inside and outside of the refrigerator. Therefore, there is a need for further improvements in the insulation performance of insulation materials used in refrigeration and freezing equipment such as refrigerators, as well as in refrigerated trucks.

[0003] Generally, a refrigerator comprises an inner box made of resin that forms the internal space, and an outer box made of metal plates or the like that forms the casing. Panel-shaped vacuum insulation material is incorporated into the gap between the inner box and the outer box. By placing the vacuum insulation material in the gap between the inner box and the outer box and filling the surrounding area with urethane foam, an insulating wall is formed in which the vacuum insulation material is embedded in the foamed insulation material.

[0004] Vacuum insulation is manufactured by housing a core material inside an outer casing and then evacuating the inside of the casing. The outer casing has gas barrier properties and functions as an outer shell that blocks the intrusion of outside air and maintains the internal vacuum. The core material functions as a skeleton that maintains its shape and structure against pressure from atmospheric pressure. The inside of the outer casing is evacuated to approximately 1 to 100 Pa. The core material, with its high thermal resistance, provides a minimum level of insulation performance over a long period of time.

[0005] Conventionally, vacuum insulation materials have been developed in which an adsorbent is sealed inside the outer packaging. Generally, a multilayer film with a gas barrier layer that prevents the permeation of oxygen, water vapor, etc. is used as the outer packaging material. When vacuum insulation materials are used for a long period of time, gases from the outside penetrate into the inside, worsening the vacuum level inside and reducing the insulation performance. To suppress this deterioration of the vacuum level, an adsorbent is sealed inside the outer packaging material to adsorb the gas inside.

[0006] Adsorbents include chemical getters, which chemically adsorb gas molecules through chemical reactions, and physical getters, which physically adsorb gas molecules through intermolecular forces. Examples of chemical getters include calcium oxide, iron powder, and alloy-based getters. Examples of physical getters include zeolites, silica gel, and activated carbon. Oxygen and moisture from the air, as well as chlorofluorocarbons (CFCs) used as foaming agents and carbon dioxide released by urethane, are immobilized by the adsorbent sealed inside the outer packaging material.

[0007] Patent Document 1 describes a vacuum insulation material in which a moisture-adsorbing substance is added to the insulation material.

[0008] Patent Document 2 describes an insulating wall for a refrigerator or the like, in which an adsorbent such as activated carbon or molecular sieve is placed on the inner side of the low-temperature side of the vacuum insulating panel. It is said that the adsorbent such as activated carbon or molecular sieve can effectively adsorb fluorocarbon gases that permeate into the vacuum insulating panel.

[0009] Patent Document 3 describes a vacuum insulation material in which metal powder is added to an insulating material filled in a plastic laminate film container. As the metal powder, iron powder, copper powder, brass powder, aluminum powder, etc. are used to remove oxygen.

[0010] Patent Document 4 describes a panel-shaped thermal insulation structure comprising a vacuum insulation material and a foamed insulation material. The outer covering material of the vacuum insulation material comprises a gas barrier layer and an outer layer located outside the gas barrier layer. In this thermal insulation structure, a moisture adsorbent is dispersed in at least one of the outer layer and the foamed insulation material.

[0011] Patent Document 5 describes an insulating material comprising a gas adsorbent containing silver ion exchange zeolite and a chemical moisture adsorbent. The chemical moisture adsorbent is said to adsorb and remove moisture that cannot be removed by industrial vacuum evacuation processes and moisture generated internally. The silver ion exchange zeolite is said to adsorb and immobilize nitrogen that cannot be removed by industrial vacuum evacuation processes and nitrogen that penetrates over time. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Unexamined Patent Publication No. Sho 59-225275 [Patent Document 2] Japanese Unexamined Patent Publication No. Sho 61-024961 [Patent Document 3] Japanese Unexamined Patent Publication No. Sho 63-105392 [Patent Document 4] Japanese Unexamined Patent Publication No. 2021-036155 [Patent Document 5] Japanese Unexamined Patent Publication No. 2006-167572 [Summary of the Invention] [Problems to be Solved by the Invention]

[0013] As an outer wrapping material for vacuum insulation materials, laminate films sealed by heat fusion are widely used. This type of outer wrapping material is formed as a multilayer film in which a gas barrier layer and a heat fusion layer are laminated. The heat fusion layer is formed of low-density polyethylene or the like. The outer wrapping material is sealed by stacking the heat fusion layers so that they face each other, then melting the heat fusion layers and integrating the outer edge portions with each other. The sealed outer wrapping material is in a state where the heat fusion layer is positioned on the innermost surface.

[0014] The present inventors have confirmed through various tests and studies that in a vacuum insulation material whose outer wrapping material is sealed by heat fusion, the heat fusion layer releases organic gas, and the accumulation of organic gas inside the outer wrapping material reduces the heat insulation performance. Hydrocarbons having 10 to 20 carbon atoms were mainly detected as the organic gas. It is expected that such a decrease in heat insulation performance due to organic gas becomes more likely to become more apparent as the degree of vacuum of the vacuum insulation material is improved for higher performance.

[0015] As described in Patent Documents 1 to 5, conventional vacuum insulation materials contain adsorbents that adsorb low molecular weight substances such as oxygen and moisture. However, even if such adsorbents can adsorb sub-nm low molecular weight substances, they cannot efficiently adsorb organic gases with larger molecular sizes. Therefore, in vacuum insulation materials sealed by heat fusion, a problem arises in that the insulation performance of the vacuum insulation material is reduced by organic gases originating from the outer packaging material.

[0016] Therefore, the present invention aims to provide a vacuum insulation material that can suppress the deterioration of insulation performance due to organic gases derived from the outer packaging material, and a refrigerator equipped with the same. [Means for solving the problem]

[0017] In other words, to solve the above problem, the vacuum insulation material according to the present invention comprises an outer packaging material having gas barrier properties, a core material filled inside the outer packaging material, and an adsorbent contained inside the outer packaging material, wherein the adsorbent has a specific surface area of ​​500 m² 2 The material is a mesoporous material with a density of 1 / g or more and well-developed mesopores with a diameter of 2 nm or more and less than 50 nm, and contains a gas adsorbent capable of adsorbing organic gases derived from the outer packaging material.

[0018] Furthermore, the refrigerator according to the present invention is a refrigerator equipped with a vacuum insulation material, the vacuum insulation material comprising an outer packaging material having gas barrier properties, a core material filled inside the outer packaging material, and an adsorbent contained inside the outer packaging material, wherein the adsorbent has a specific surface area of ​​500 m² 2 The material is a mesoporous material with a density of 1 / g or more and well-developed mesopores with a diameter of 2 nm or more and less than 50 nm, and contains a gas adsorbent capable of adsorbing organic gases derived from the outer packaging material. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a vacuum insulation material that can suppress the deterioration of insulation performance due to organic gases derived from the outer packaging material, and a refrigerator equipped with the same. [Brief explanation of the drawing]

[0020] [Figure 1] This is a cross-sectional view showing the structure of a vacuum insulation material according to an embodiment of the present invention. [Figure 2] A cross-sectional view showing the structure of the outer packaging material for a vacuum insulation material according to an embodiment of the present invention. [Figure 3] This is a front view of a refrigerator according to an embodiment of the present invention. [Figure 4] This is a cross-sectional view of a refrigerator according to an embodiment of the present invention. [Modes for carrying out the invention]

[0021] The following describes a vacuum insulation material according to one embodiment of the present invention, and a refrigerator equipped therewith. In the following figures, common components are denoted by the same reference numerals, and redundant explanations are omitted. In this specification, "~" means a numerical range that includes the numbers before and after it as the lower and upper limits.

[0022] Figure 1 is a cross-sectional view showing the structure of a vacuum insulation material according to an embodiment of the present invention. Figure 2 is a cross-sectional view showing the structure of the outer packaging material of a vacuum insulation material according to an embodiment of the present invention. Figure 1 schematically shows the structure of a flat vacuum insulation panel, which is an example of a vacuum insulation material. Figure 2 schematically shows the cross-sectional structure of the outer packaging material of the vacuum insulation material. In Figure 2, the upper side is the exterior side of the vacuum insulation material, and the lower side is the interior side of the vacuum insulation material.

[0023] As shown in Figure 1, the vacuum insulation material 100 according to this embodiment comprises a gas barrier outer packaging material 101, a core material 102 filled inside the outer packaging material 101, and an adsorbent 103 housed inside the outer packaging material 101. In Figure 1, the adsorbent 103 is housed inside the outer packaging material 101 in a packaged body. The packaged body is embedded parallel to the vacuum insulation panel on the central side of the core material 102.

[0024] The outer packaging material 101 is a component that creates a highly insulated vacuum space inside by evacuating its interior. The outer packaging material 101 functions as an outer shell that blocks the intrusion of outside air and maintains the internal vacuum. The outer packaging material 101 is formed from a multilayer film with gas barrier properties that can be heat-sealed. The outer packaging material 101 contains a core material 102 and an adsorbent 103 inside, and after the interior is reduced to a high degree of vacuum, it is sealed by heat fusion.

[0025] As shown in Figure 2, the outer packaging material 101 is formed by laminating, in this order, a base material 111 that supports and protects the multilayer structure, a gas barrier layer 112 that functions as a gas barrier to prevent the permeation of gases such as oxygen and water vapor, and a heat-sealable layer 113 that is heat-sealed when the outer packaging material 101 is sealed. On the inner surface side of the outer packaging material 101, the heat-sealable layer 113 is positioned in contact with the vacuum space in which the core material 102 is housed.

[0026] Examples of materials for the base material 111 include polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, and ethylene-vinyl acetate copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as polyamide 66 and polyamide 6; polystyrene, polycarbonate, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacrylonitrile, polyvinyl fluoride, polyvinyl chloride, polyvinylidene chloride, (meth)acrylic resin, and cellulose resin.

[0027] The base material 111 may be a biaxially oriented film, a uniaxially oriented film, or an unoriented film. From the viewpoint of ensuring the strength and rigidity of the outer packaging material 101, it is preferable to use a biaxially oriented film as the base material 111. As for the material of the base material 111, biaxially oriented polypropylene or polyethylene terephthalate are preferred due to their high rigidity and heat resistance.

[0028] The gas barrier layer 112 can be made of inorganic materials or resins with high gas barrier properties. The gas barrier layer 112 may consist of a resin layer formed from a resin with high gas barrier properties or a base resin, or an inorganic layer formed from inorganic materials. The inorganic layer can be formed by physical vapor deposition (PVD) methods such as vacuum deposition or sputtering, chemical vapor deposition (CVD) methods such as inductively coupled plasma or atmospheric pressure plasma, or by lamination of metal foil.

[0029] Materials for the inorganic layer include aluminum oxide, silicon oxide, magnesium oxide, indium oxide, aluminum, lead, copper, silver, and gold. Materials for the resin layer include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, (meth)acrylic acid-vinyl alcohol copolymer, poly(meth)acrylic acid, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyester, and polyamide.

[0030] The gas barrier layer 112 is preferably formed by laminating a resin film on which an inorganic layer has been formed by vapor deposition with a resin film on which a resin layer with high gas barrier properties has been formed. With such a structure, high gas barrier properties can be obtained from the vapor-deposited layer, and the gas barrier properties can be reinforced by the resin layer. Pinholes that occur in the vapor-deposited layer and their effects can be suppressed by the resin layer, while the decrease in the gas barrier properties of the resin layer due to moisture absorption can be suppressed by the vapor-deposited layer.

[0031] The material for the heat-sealing layer 113 has a density of 0.910 g / cm³. 3 More than 0.930g / cm 3 Linear or branched low-density polyethylene with a density of less than 0.930 g / cm³ 3 More than 0.942g / cm 3 Medium-density polyethylene with a density of less than 0.942 g / cm³ 3 Examples of high-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polymethylpentene, etc., are mentioned above.

[0032] As the material for the heat-sealable layer 113, polyethylene is preferred, low-density polyethylene is more preferred, and linear low-density polyethylene is even more preferred, due to its ability to be heat-sealed at low temperatures, its high peel resistance, and the enhanced effect of encapsulating organic gas adsorbents.

[0033] The outer packaging material 101 can be provided in any suitable multilayer structure, as long as it includes a gas barrier layer 112 and a heat-sealable layer 113. For example, a base layer for adhering the gas barrier layer 112 and a crystalline resin layer in which crystalline polymers are oriented may be formed on the substrate 111. Examples of crystalline polymers include polyether ether ketone, polyphenylene sulfide, and polybutylene terephthalate. In addition, an adhesive layer may be formed to bond the layers together.

[0034] The outer packaging material 101 may comprise a single gas barrier layer 112, or it may comprise multiple gas barrier layers 112. The multiple gas barrier layers 112 may be formed from the same material or from different materials.

[0035] The core material 102 is a component that is filled inside the outer packaging material 101 and maintains the vacuum space created by the vacuum pump inside the outer packaging material 101. The core material 102 functions as a framework that maintains the shape and structure of the vacuum insulation material against pressurization such as atmospheric pressure. In order to suppress heat transfer by itself, the core material 102 is formed with a low filling density using a material with low thermal conductivity.

[0036] The core material 102 can be formed from any suitable material, provided that it has low thermal conductivity, sufficient strength to maintain the thickness of the outer packaging material 101 after vacuuming, and releases little gas. The core material 102 may be formed from a porous material, or from an aggregate of fibers or particles that can maintain space around it. From the viewpoint of maintaining its shape, the core material 102 may be pressure-molded into a board or web shape, bound with a binder, or packaged in a packaging body.

[0037] Examples of materials for the core material 102 include inorganic fibers such as glass wool, rock wool, silica fibers, and alumina fibers; inorganic particles such as silica, diatomaceous earth, perlite, clay, talc, kaolin, and calcium carbonate; resin fibers such as cellulose, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyester, polyamide, and (meth)acrylic resin; resin nonwoven fabrics and resin particles; foamed resins such as polyethylene, polypropylene, and polystyrene; and aerogels such as silica, alumina, and carbon.

[0038] The adsorbent 103 is contained inside the outer packaging material 101 and adsorbs gases inside the outer packaging material 101. The adsorbent 103 immobilizes gases that have entered the outer packaging material 101 from the outside or released from the outer packaging material 101 through physical and chemical adsorption. By sealing the adsorbent 103 inside the outer packaging material 101, the decrease in the vacuum level inside the outer packaging material 101 over time is suppressed.

[0039] The vacuum insulation material 100 can be manufactured, for example, by overlapping two film-like outer packaging materials 101, heat-sealing three sides to form a bag, housing a core material 102 and an adsorbent 103 inside the outer packaging material 101, and then, under a vacuum atmosphere, evacuating the inside of the outer packaging material 101 before heat-sealing the remaining side. The sealing of the outer packaging material 101 is performed by overlapping the outer packaging material 101 so that the heat-sealing layers 113 formed on the inner surface of the outer packaging material 101 face each other.

[0040] When sealing the outer packaging material 101, the outer packaging materials 101 are overlapped, and the heat-sealing layers 113 formed on the inner surface of the outer packaging material 101 are brought into close contact. Then, the outer edges of the outer packaging material 101 are heated to a temperature above the melting point of the heat-sealing layers 113. When the heat-sealing layers 113 are melted using a heat sealing device or the like and the outer edges are integrated, the outer packaging material 101 is sealed by heat fusion. Typically, the vacuum insulation material 100 is incorporated into the product after the outer edges of the outer packaging material 101 are folded towards the center.

[0041] Generally, when vacuum insulation material is installed in refrigerators and the like, it is incorporated into the gap between the inner box that forms the internal space and the outer box that forms the enclosure. Vacuum insulation material is formed, for example, as a plate-shaped vacuum insulation panel with a thickness of 10 to 20 mm. By laminating the vacuum insulation material to the inner surface of the outer box and inserting the inner box inside the outer box to join them, an insulated box body is assembled in which the vacuum insulation material is incorporated into the gap between the inner box and the outer box.

[0042] The gap between the inner and outer boxes of the insulated box is filled with foamed insulation material. After inserting vacuum insulation material into the gap, the raw material liquid for the foamed insulation material is injected into the gap and foamed, forming the foamed insulation material around the vacuum insulation material. Through this process, an insulated wall is formed in which the vacuum insulation material is embedded in the foamed insulation material. Rigid polyurethane foam is used as the foamed insulation material.

[0043] Vacuum insulation materials are subjected to atmospheric pressure and the foaming pressure during the foaming process after being evacuated. They are also exposed to oxygen and water vapor in the atmosphere, as well as foaming gases such as carbon dioxide produced during the foaming process. Furthermore, they are affected by heat due to the heat generated by the foaming reaction. Therefore, in order to ensure the insulation performance required for products such as refrigerators over a long period of time, vacuum insulation materials require high gas barrier properties, low thermal conductivity, and resistance to thermal effects.

[0044] Generally, the permeation of gas from the outside to the inside of a vacuum insulation material cannot be completely prevented, even when using an outer packaging material with gas barrier properties. Furthermore, during the manufacturing of vacuum insulation materials, gas may be mixed into the outer packaging material before sealing. Conventionally, adsorbents have been sealed inside the outer packaging material to capture such gases. By adsorbing the gas inside the outer packaging material with the adsorbent, the deterioration of the vacuum level inside the outer packaging material can be suppressed.

[0045] Gases that degrade the vacuum degree of vacuum insulation materials include oxygen, water vapor, carbon dioxide, nitrogen, etc. in air that enter through pinholes formed in the outer packaging material, gaps in heat-sealed parts, etc., and foaming gases such as carbon dioxide released during foam molding of foamed insulation materials. There are also moisture adsorbed by the outer packaging material and core material before the production of the vacuum insulation material, unreacted raw material substances and by-products generated during the production of the outer packaging material and core material, and low-molecular-weight organic substances that scatter and are adsorbed to the outer packaging material and core material.

[0046] In order to maintain the vacuum degree of a vacuum insulation material, it is important to prevent the influence of not only gas that has intruded into the interior from the outside of the vacuum insulation material, but also gas generated inside the vacuum insulation material. The present inventors have confirmed through various tests and studies that in a vacuum insulation material whose outer packaging material is sealed by heat fusion, the heat fusion layer located on the inner surface side of the outer packaging material releases organic gas, and the accumulation of organic gas inside the outer packaging material reduces the heat insulation performance of the vacuum insulation material. As the organic gas, hydrocarbons having 10 to 20 carbon atoms were mainly detected at a high concentration.

[0047] Generally, the heat fusion layer is formed on the inner surface side of the outer packaging material from a thermoplastic resin such as low-density polyethylene or polypropylene. During synthesis of the material forming the heat fusion layer, by-products such as hydrocarbon oligomers with low carbon numbers may be generated. Such organic gas is released from the heat fusion layer into the interior of the outer packaging material after the production of the vacuum insulation material. When such organic gas is released into the interior of the outer packaging material, a problem arises in that the heat insulation performance of the vacuum insulation material decreases.

[0048] Examples of the organic gas released from the heat fusion layer include hydrocarbons having 10 to 20 carbon atoms, such as decane (C 10 H 22 ), dodecane (C 12 H 26 ), tetradecane (C 14 H 30 ), hexadecane (C 16 H 34 ), octadecane (C 18 H 38 ), icosane (C 20 H 42These include oligomers formed by the polymerization of ethylene monomers such as ) and oligomers formed by the polymerization of propylene monomers.

[0049] Hydrocarbons with 10 to 20 carbon atoms tend to be produced in larger quantities as by-products during the synthesis of materials that form heat-sealed layers compared to hydrocarbons with 21 or more carbon atoms. Furthermore, hydrocarbons with 10 to 20 carbon atoms tend to be less prone to volatilization during the synthesis of materials that form heat-sealed layers and during the formation of heat-sealed layers, compared to hydrocarbons with 9 or fewer carbon atoms.

[0050] Hydrocarbons with 10 to 20 carbon atoms tend to remain in the heat-sealed layer, and after the manufacturing of vacuum insulation material, they are easily released from the heat-sealed layer into the interior of the outer packaging material. When vacuum insulation material is used for a long period of time, such organic gases accumulate inside the outer packaging material, and the insulation performance of the vacuum insulation material deteriorates over time. It is expected that the deterioration of insulation performance due to organic gases will become more apparent as the vacuum level of the vacuum insulation material improves due to the development of high-performance vacuum insulation material.

[0051] Therefore, in the vacuum insulation material 100 according to this embodiment, at least an organic gas adsorbent capable of adsorbing organic gases originating from the heat-sealed layer 113 of the outer packaging material 101 is used as the adsorbent 103 for adsorbing gases inside the outer packaging material 101. The organic gas adsorbent used is a mesoporous adsorbent with well-developed mesopores having a diameter of 2 nm or more and less than 50 nm, and capable of adsorbing hydrocarbons having 10 to 20 carbon atoms.

[0052] As the adsorbent 103, only an organic gas adsorbent capable of adsorbing organic gases may be enclosed, or a combination of an organic gas adsorbent capable of adsorbing organic gases and a low molecular weight gas adsorbent capable of adsorbing low molecular weight gases other than organic gases may be enclosed. Examples of low molecular weight gases are gaseous low molecular weights with molecular sizes smaller than hydrocarbons having 10 to 20 carbon atoms, such as oxygen, water vapor, carbon dioxide, nitrogen, chlorofluorocarbons (CFCs), and volatile organic substances having 9 or fewer carbon atoms.

[0053] The adsorbent 103 may be dispersed inside the outer packaging material 101, enclosed in a gas-permeable packaging body, enclosed as a component of the core material 102, or enclosed fixed to the core material 102 or carrier. As the packaging body, a net-like or non-woven fabric bag with ventilation holes, or a bag or laminate pack made of a gas-permeable film can be used.

[0054] The organic gas adsorbent and the low molecular weight gas adsorbent may be mixed together and sealed, or sealed separately without mixing. In a gas-permeable packaging, the organic gas adsorbent and the low molecular weight gas adsorbent may be packaged together or individually. The core material 102 may contain the organic gas adsorbent and the low molecular weight gas adsorbent mixed together and immobilized, or they may be incorporated or immobilized individually.

[0055] As organic gas adsorbents, carbon materials such as activated carbon, mesoporous carbon, and carbon black, as well as organic-inorganic hybrid aerogels such as zeolites, molecular sieves, mesoporous silica, and organopolysiloxanes in which polysiloxane chains and organic chains are covalently bonded, can be used.

[0056] As an organic gas adsorbent, carbon materials are preferable, and activated carbon is more preferable. With carbon materials, many nonpolar adsorption sites can be obtained on the surface of the material and inside the pores. Therefore, nonpolar hydrocarbons originating from the outer packaging material 101 can be adsorbed efficiently and in large quantities. With activated carbon, a certain degree of pore size distribution can be obtained at low cost, so various organic gases originating from the outer packaging material 101 can be adsorbed efficiently while suppressing costs.

[0057] Activated carbon can be in powder, granular, spherical, or fibrous form, as well as molded or granulated form. Materials for activated carbon include wood, bamboo, sawdust, pulp, coconut shells, bagasse, coal, coke, and coal pitch.

[0058] As for the method of activating activated carbon, a physical activation method using oxidizing gases such as water vapor or air may be used, as long as well-developed mesopores can be obtained, or a chemical activation method using chemicals such as zinc chloride, magnesium chloride, calcium chloride, phosphoric acid, sulfuric acid, or alkali may be used.

[0059] As mesoporous carbon, any type synthesized by physical activation, chemical activation, template method, mixing method, sol-gel method, etc. may be used. Physical activation and chemical activation can be carried out, for example, by using a porous carbon material with well-developed micropores as a raw material and expanding the micropores into mesopores using an oxidizing gas or chemical agent.

[0060] The molding method involves synthesizing carbon using a mesoporous material such as mesoporous silica as a mold, and then removing the mold. The mixing method involves mixing a precursor resin with a pyrolytic resin that will become pologen, and then synthesizing carbon and pyrolytic resin by heat treatment. The sol-gel method involves synthesizing an organic gel by a sol-gel reaction, and then carbonizing the organic gel.

[0061] As the low molecular weight gas adsorbent, either a physical adsorbent or a chemical adsorbent or absorbent may be used. Examples of low molecular weight gas adsorbents include zeolites, molecular sieves, silica gel, activated alumina, silica alumina, silica magnesia, calcium oxide, magnesium oxide, barium oxide, magnesium chloride, calcium chloride, calcium sulfate, magnesium sulfate, zirconium alloy, magnesium alloy, iron powder, acid clay, activated clay, and metal-organic frameworks (MOFs).

[0062] As a low-molecular-weight gas adsorbent, it is preferable to use at least calcium oxide. Calcium oxide reacts with water to produce calcium hydroxide. Therefore, water vapor can be fixed by chemical absorption, which is less prone to desorption. In addition, acidic gases such as carbon dioxide can be fixed by calcium hydroxide.

[0063] The types of molecules that can be adsorbed and the adsorption performance of organic gas adsorbents such as activated carbon vary greatly depending on the specific surface area and pore size. Since the inside of the outer packaging material 101 is evacuated, the organic gas adsorbent needs to exhibit adsorption performance in a high-vacuum space. For this reason, it is preferable to use an organic gas adsorbent that has well-developed mesopores and a high adsorption rate of hydrocarbons with 10 to 20 carbon atoms in an atmosphere with a vacuum of 1 to 10 Pa.

[0064] The adsorption rate of hydrocarbons with 10 to 20 carbon atoms by the organic gas adsorbent is preferably 1.0 × 10 in an atmosphere with a vacuum of 1 to 10 Pa. -10 mol / (min·g) or more, more preferably 2.0 × 10⁻⁶ -10 mol / (min·g) or more, more preferably 4.0 × 10 -10 mol / (min·g) or more, more preferably 6.0 × 10 -10 mol / (min·g) or more, more preferably 8.0 × 10 -10 The concentration is mol / (min·g) or higher.

[0065] The greater the adsorption rate of hydrocarbons with 10 to 20 carbon atoms, the more quickly organic gases released from the heat-sealed layer 113 can be adsorbed. Because the adsorption equilibrium can be shifted towards the adsorption side, it becomes possible to maintain a high degree of vacuum inside the outer packaging material 101. Therefore, the thermal insulation performance of the vacuum insulation material 100 can be improved compared to conventional materials. Note that the adsorption rate of hydrocarbons with 10 to 20 carbon atoms is typically at most 10.0 × 10⁻⁶. -10 It is less than or equal to mol / (min·g).

[0066] Organic gas adsorbents preferably have a mesoporous structure with well-developed mesopores. The molecular size of hydrocarbons with 10 to 20 carbon atoms is approximately 1.3 to 2.5 nm. Well-developed mesopores ensure sufficient adsorption sites and specific surface area for hydrocarbons with 10 to 20 carbon atoms, allowing for efficient and large-scale adsorption at a high adsorption rate. Furthermore, hydrocarbons with 10 to 20 carbon atoms can be selectively adsorbed even in spaces where low molecular weight molecules are present. Since the adsorption capacity is less easily depleted, hydrocarbon adsorption can be continued for a longer period of time.

[0067] In this specification, "well-developed mesopores" means that the volume ratio of mesopores per 100% of the total pore volume is the largest among the volume ratios of micropores, mesopores, and macropores. The pores of the adsorbent are composed of micropores, mesopores, and macropores. Micropores are defined as pores with a diameter of 2 nm or less. Mesopores are defined as pores with a diameter greater than 2 nm but less than 50 nm. Macropores are defined as pores with a diameter of 50 nm or more. However, for the purpose of calculating volume ratios, pores with a diameter of 50 nm or more and 100 nm or less shall be treated as macropores.

[0068] The volume ratio of mesopores per 100% of the total pore volume of the organic gas adsorbent is preferably more than 50% by volume, more preferably 55% or more by volume, even more preferably 60% or more by volume, even more preferably 65% ​​or more by volume, even more preferably 70% or more by volume, even more preferably 75% or more by volume, and even more preferably 80% or more by volume. The larger the volume ratio of mesopores, the more efficiently and in larger quantities hydrocarbons with 10 to 20 carbon atoms can be adsorbed at a high adsorption rate.

[0069] The volume fraction of micropores per 100% of the total volume of pores in the organic gas adsorbent is preferably less than 50% by volume, more preferably less than 40% by volume, even more preferably less than 30% by volume, even more preferably less than 20% by volume, and even more preferably less than 10% by volume. The smaller the volume fraction of micropores, the more selectively hydrocarbons with 10 to 20 carbon atoms can be adsorbed. However, when the organic gas adsorbent adsorbs low molecules along with the organic gas, the volume fraction of micropores may be 10% or more by volume, 20% or more by volume, 30% or more by volume, or 40% or more by volume.

[0070] The macropore volume ratio per 100% of the total pore volume of the organic gas adsorbent is preferably less than 50% by volume, more preferably less than 40% by volume, even more preferably less than 30% by volume, even more preferably less than 20% by volume, and even more preferably less than 10% by volume. The smaller the macropore volume ratio, the more efficiently and in larger quantities hydrocarbons with 10 to 20 carbon atoms can be adsorbed.

[0071] The organic gas adsorbent preferably has well-developed mesopores with a diameter of more than 2 nm and less than 40 nm, more preferably with well-developed mesopores with a diameter of more than 2 nm and less than 30 nm, even more preferably with well-developed mesopores with a diameter of more than 2 nm and less than 20 nm, and even more preferably with well-developed mesopores with a diameter of more than 2 nm and less than 10 nm.

[0072] The smaller the diameter of the well-developed mesopores, the more selectively hydrocarbons with 10 to 20 carbon atoms can be adsorbed. Furthermore, by securing adsorption sites and specific surface area for hydrocarbons with 10 to 20 carbon atoms, large amounts of these hydrocarbons can be adsorbed. In this specification, "well-developed mesopores with a diameter within a predetermined range" means that the volume ratio of mesopores within that range per 100% of the total volume of mesopores exceeds 50% by volume.

[0073] The specific surface area of ​​the organic gas adsorbent is preferably 500 m². 2 / g or more, more preferably 700m2 / g or more, more preferably 900m 2 / g or more, more preferably 1100m 2 / g or more, more preferably 1400m 2 It is 1 / g or more. Also, for example, 3000m 2 Less than / g, or 2500m 2 Less than / g, or 2000m 2 It is less than / g. The larger the specific surface area, the more gas can be adsorbed. However, if the specific surface area is too large, it becomes difficult to obtain well-developed mesopores.

[0074] In the initial state after the vacuum insulation material 100 has been evacuated from the inside of the outer packaging material 101 and before it is installed in the product and used, the internal pressure of the outer packaging material 101 is preferably 100 Pa or less, more preferably 10 Pa or less, even more preferably 5 Pa or less, and still more preferably 1 Pa or less. The higher the vacuum level and the lower the internal pressure inside the outer packaging material 101, the higher the insulation performance that can be obtained. Because an organic gas adsorbent is sealed inside, even when the vacuum level is increased to a high level, a significant decrease in insulation performance due to organic gases can be suppressed.

[0075] In Figure 1, the adsorbent 103 is embedded in the core material 102 near the center of the outer packaging material 101. However, the organic gas adsorbent may be placed closer to the center of the outer packaging material 101, or closer to the outside of the outer packaging material 101. The organic gas adsorbent may be embedded towards the center of the core material 102, or it may be placed so as to be in contact with the inner surface of the outer packaging material 101. Placing it closer to the center allows for more efficient collection of organic gases released from the outer packaging material 101. On the other hand, placing it closer to the outside makes it easier to fix it to the inner surface of the outer packaging material 101.

[0076] According to the vacuum insulation material 100 described above, the adsorbent 103 used to adsorb gas inside the outer packaging material 101 is a mesoporous organic gas adsorbent with well-developed mesopores that can adsorb hydrocarbons with 10 to 20 carbon atoms. Therefore, even if the heat-sealed layer 113 releases organic gas, the organic gas released inside the outer packaging material 101 is adsorbed and fixed by the organic gas adsorbent. The accumulation and diffusion of organic gas as a gas inside the outer packaging material 101 is suppressed. Thus, a vacuum insulation material can be provided that can suppress the deterioration of insulation performance due to organic gas originating from the outer packaging material.

[0077] In particular, with the vacuum insulation material 100 described above, organic gases that were not immobilized with conventional adsorbents are immobilized, making it possible to achieve a higher degree of vacuum than before and thus a lower thermal conductivity than before. Furthermore, since the organic gas adsorbent can be used in combination with a low molecular weight adsorbent, the adsorption capacity is less likely to be depleted compared to when only a low molecular weight adsorbent is used. Therefore, the deterioration of the insulation performance of the vacuum insulation material is suppressed over a long period of time, and it is possible to sustainably exhibit higher insulation performance than before.

[0078] Figure 3 is a front view of a refrigerator according to an embodiment of the present invention. Figure 4 is a cross-sectional view of a refrigerator according to an embodiment of the present invention. Figure 4 corresponds to the cross-sectional view by line II in Figure 3. Figures 3 and 4 show an example of a refrigerator equipped with a vacuum insulation material. The vacuum insulation material 100 containing an organic gas adsorbent can be provided as an insulating wall of the refrigerator.

[0079] As shown in Figures 3 and 4, the refrigerator 1 comprises an insulated box 1a, which is an insulated box that separates the outside from the inside of the refrigerator, and insulated doors 2a, 2b, 3a, 4a, 5a, and 6a that open and close the opening of the insulated box 1a.

[0080] The interior of the insulated box 1a is divided into multiple storage compartments. In Figures 3 and 4, the refrigerator 1 is equipped with a refrigerator compartment 2, an ice-making compartment 3, an upper freezer compartment 4, a lower freezer compartment 5, and a vegetable compartment 6, arranged in this order from top to bottom. The ice-making compartment 3 and the upper freezer compartment 4 are positioned side by side between the refrigerator compartment 2 and the lower freezer compartment 5.

[0081] Refrigerator compartment 2 is equipped with refrigerator doors 2a and 2b at the front. Ice maker compartment 3 is equipped with an ice maker door 3a at the front. Upper freezer compartment 4 is equipped with an upper freezer door 4a at the front. Lower freezer compartment 5 is equipped with a lower freezer door 5a at the front. Vegetable compartment 6 is equipped with a vegetable compartment door 6a at the front.

[0082] The refrigerator doors 2a and 2b are double-opening insulated doors that rotate to open and close independently on the left and right sides. The refrigerator doors 2a and 2b are attached to the upper and lower front ends of the left and right sides of the insulated box body 1a via hinges. The upper hinges are covered by a hinge cover 16. Inside the hinge cover 16, an outside air temperature sensor for detecting the outside air temperature and an outside air humidity sensor for detecting the outside air humidity are installed.

[0083] The ice-making compartment door 3a, the upper freezer compartment door 4a, the lower freezer compartment door 5a, and the vegetable compartment door 6a are retractable insulated doors, designed to be retractable along with the containers forming each storage compartment. The upper freezer compartment 4 houses the upper freezer compartment container 4b. The lower freezer compartment 5 houses the lower freezer compartment container 5b. The vegetable compartment 6 houses the vegetable compartment container 6b. The ice-making compartment 3 houses the ice-making compartment container.

[0084] Refrigerated compartment 2 is a storage room where the internal temperature is cooled to a refrigerated temperature range of 0°C or higher, for example, to an average of around 2-4°C. Multiple door pockets 33 capable of storing items are provided on the inside of the refrigerated compartment doors 2a and 2b. Multiple shelves 34 capable of placing items are provided in refrigerated compartment 2. An internal storage compartment 35 is formed in the lower part of refrigerated compartment 2. The internal storage compartment 35 is a space where cold air is not blown in, maintaining a low temperature and suppressing drying.

[0085] The ice-making compartment 3 is a space for ice making and storage where the internal temperature is below 0°C, for example, cooled to an average of around -20°C. The upper freezer compartment 4 and the lower freezer compartment 5 are storage compartments where the internal temperature is below 0°C, for example, cooled to an average of around -20°C. The vegetable compartment door 6 is a storage compartment where the internal temperature is above 0°C, for example, cooled to an average of around 6°C.

[0086] The refrigerator compartment 2, the ice-making compartment 3, and the upper freezer compartment 4 are separated by an insulated partition wall 28. The ice-making compartment 3 and the upper freezer compartment 4 are separated from the lower freezer compartment 5 by an insulated partition wall 29. The lower freezer compartment 5 and the vegetable compartment 6 are separated by an insulated partition wall 30.

[0087] Furthermore, an insulating partition wall is provided on the front side between the ice-making compartment door 3a and the upper freezer compartment door 4a to prevent leakage of cold air and intrusion of outside air. These insulating partition walls are made of styrene foam, rigid polyurethane foam, or the like. These insulating partition walls are provided to be, for example, 30 to 50 mm thick.

[0088] As shown in Figure 4, a machine room 39 is provided on the rear side of the vegetable compartment 6. The machine room 39 houses a compressor 20 and an evaporation tray 32. The compressor 20 is connected to a radiator (not shown), a first cooler 14a, and a second cooler 14b via refrigerant piping. The refrigerant circuit is formed by the compressor 20, an external radiator and radiating piping that function as a condenser, the first cooler 14a and the second cooler 14b that function as evaporators, a capillary tube for refrigeration and freezing that functions as a pressure reducer, and the refrigerant piping that connects these components.

[0089] In the refrigerant circuit, the refrigeration cycle is carried out by the circulation of refrigerant and heat exchange. In the refrigerant circuit, the refrigerant is compressed by the compressor 20, condensed by the radiator, depressurized by the pressure reducer, and evaporated by the evaporator, and cold air is generated by the first cooler 14a and the second cooler 14b. The flow of refrigerant to the first cooler 14a and the second cooler 14b is switched between each other by a three-way valve. The cold air generated by the first cooler 14a and the second cooler 14b is blown to each storage chamber for refrigeration or freezing.

[0090] A first cooler compartment 8a is formed on the rear side of the lower freezer compartment 5. A first cooler 14a is installed in the first cooler compartment 8a. The first cooler 14a is a freezer cooler that generates cold air to cool the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6.

[0091] A first fan 9a is installed above the first cooler 14a in the first cooler compartment 8a. The first fan 9a is a fan that blows the cold air generated by the first cooler 14a to the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6.

[0092] The lower freezer compartment 5 and the first cooler compartment 8a are separated by a partition member 26a. A first freezer compartment outlet 12a is formed at the top of the partition member 26a so as to open to the top of the lower freezer compartment 5. The first freezer compartment outlet 12a connects the first cooler compartment 8a and the lower freezer compartment 5 via the first fan 9a and the air passage 11a above the first cooler compartment 8a.

[0093] The upper freezer compartment 4 and the air passage 11a above the first cooler compartment 8a are separated by a partition member 26b. A second freezer compartment outlet 12b is formed at the top of the partition member 26b so as to open to the top of the upper freezer compartment 4. The second freezer compartment outlet 12b connects the first cooler compartment 8a and the upper freezer compartment 4 via the first fan 9a and the air passage 11a above the first cooler compartment 8a.

[0094] The first cooler chamber 8a and the vegetable compartment 6 are connected via air passages and dampers (not shown). A freezer return port 13a is formed at the bottom of the partition member 26a of the lower freezer compartment 5, opening to the bottom of the lower freezer compartment 5. The freezer return port 13a connects the lower freezer compartment 5 and the first cooler chamber 8a.

[0095] The cold air generated by the first cooler 14a is discharged from the first cooler chamber 8a through the first freezer chamber outlet 12a to the lower freezer chamber 5. It is also discharged from the first cooler chamber 8a through the second freezer chamber outlet 12b to the upper freezer chamber 4. Furthermore, it is discharged to the vegetable compartment 6 through air passages and dampers (not shown). Finally, it returns to the first cooler chamber 8a from the lower freezer chamber 5, upper freezer chamber 4, and vegetable compartment 6 through the freezer chamber return port 13a, where it is re-cooled by the first cooler 14a.

[0096] A heater 21 is installed at the bottom of the first cooler chamber 8a. The heater 21 is for heating the first cooler 14a. A first drain 23a is provided at the bottom of the first cooler chamber 8a. A first drain port 24a opens at the bottom of the first drain 23a. A first drain pipe 25a is connected to the first drain port 24a. The first drain pipe 25a communicates with the ceiling above the evaporator tray 32 in the machine room 39.

[0097] When frost forms on the first cooler 14a, the first cooler 14a is heated by the heater 21 to remove the frost. The water droplets generated during defrosting are collected in the first gutter 23a and discharged into the first drain port 24a. They then flow through the first drain pipe 25a to the machine room 39 and are collected in the evaporation tray 32 installed in the machine room 39. The water droplets collected in the evaporation tray 32 are heated by exhaust heat, etc., and removed by evaporation.

[0098] A second cooler compartment 8b is formed on the rear side of the refrigerator compartment 2. A second cooler 14b is installed in the second cooler compartment 8b. The second cooler 14b is a refrigerating cooler that generates cold air to cool the refrigerator compartment 2.

[0099] A second fan 9b is installed above the second cooler 14b in the second cooler room 8b. The second fan 9b is a fan that blows the cold air generated by the second cooler 14b into the refrigerator room 2.

[0100] The refrigerator compartment 2 and the second cooler compartment 8b are separated by a partition member 26c. In the middle of the partition member 26c, a first refrigerator compartment outlet 12c is formed so as to open between the shelves 34 of the refrigerator compartment 2. The first refrigerator compartment outlet 12c connects the second cooler compartment 8b and the refrigerator compartment 2 via an air passage 11b above the second cooler compartment 8b.

[0101] A second refrigerator compartment outlet 12d is formed at the top of the partition member 26c so as to open to the top of the refrigerator compartment 2. The second refrigerator compartment outlet 12d connects the second cooler compartment 8b and the refrigerator compartment 2 via an air passage 11b located above the second cooler compartment 8b.

[0102] A refrigerator compartment return opening 13b is formed at the lower part of the partition member 26c so as to open to the lower part of the refrigerator compartment 2. The refrigerator compartment return opening 13b connects the refrigerator compartment 2 and the second cooler compartment 8b.

[0103] The cold air generated by the second cooler 14b is discharged from the second cooler chamber 8b through the first refrigerator chamber outlet 12c to the middle section of the refrigerator chamber 2. It is also discharged from the second cooler chamber 8b through the second refrigerator chamber outlet 12d to the upper part of the refrigerator chamber 2. Finally, it returns from the refrigerator chamber 2 to the second cooler chamber 8b through the refrigerator chamber return outlet 13b and is re-cooled by the second cooler 14b.

[0104] A second drainpipe 23b is provided at the bottom of the second cooler room 8b. A second drain outlet (not shown) is open at the bottom of the second drainpipe 23b. A second drain pipe (not shown) is connected to the second drain outlet. The second drain pipe communicates with the ceiling above the evaporator tray 32 in the machine room 39.

[0105] When frost forms on the second cooler 14b, the second cooler 14b is heated by the air circulating in the refrigerator compartment 2 and defrosted. The water droplets generated during defrosting are collected in the second drain 23b and discharged to the second drain outlet. They then flow through the second drain pipe to the machine room 39 and are collected in the evaporation tray 32 installed in the machine room 39. The water droplets collected in the evaporation tray 32 are heated by exhaust heat, etc., and removed by evaporation.

[0106] A control board 31 is built into the upper part of the insulated box 1a. The control board 31 is equipped with a CPU, memory such as ROM and RAM, and interface circuits. An outside air temperature sensor, an outside air humidity sensor, a refrigerator compartment temperature sensor, a freezer compartment temperature sensor, a vegetable compartment temperature sensor, a cooler temperature sensor, a door sensor, and the like are connected to the control board 31 via wiring.

[0107] The control board 31 controls the compressor 20, the first fan 9a, the second fan 9b, the damper, etc., based on the detection results from the sensors and the settings of the control unit 18. The control unit 18 is located on the inner wall of the refrigerator compartment 2. The control unit 18 allows the user to adjust the temperature of each storage compartment and to issue instructions for additional functions. Additional functions include a rapid freezing function that performs rapid freezing in the upper freezer compartment 4 and the lower freezer compartment 5.

[0108] As shown in Figure 4, the insulated box 1a is formed by an inner box 1b that forms the internal space and an outer box 1c that forms the enclosure. The inner box 1b is formed as a resin molded product by molding or the like. The outer box 1c is formed from a metal plate or the like. The outer box 1c is formed, for example, by joining together a top plate and left and right side plates made by bending a steel plate into a gate shape, a back plate made of steel plate, and a bottom plate made of steel plate.

[0109] Vacuum insulation material or foamed insulation material is provided in the gaps between the inner box 1b and the outer box 1c, and in the gaps inside the insulated doors 2a, 2b, 3a, 4a, 5a, and 6a to insulate the inside from the outside of the storage compartment. By using vacuum insulation material, which has a lower thermal conductivity than foamed insulation material, high insulation performance is ensured while maintaining the volume of the storage compartment. As the vacuum insulation material, the aforementioned vacuum insulation material 100 containing an organic gas adsorbent can be used. As the foamed insulation material, rigid polyurethane foam or the like can be used.

[0110] In Figure 4, the vacuum insulation material 100 containing the organic gas adsorbent is installed in the gaps between the inner box 1b and the outer box 1c that form the insulated box 1a, specifically in the gaps on the top surface of the insulated box 1a, the gaps on the bottom surface of the insulated box 1a, the gaps on the left and right sides of the insulated box 1a, and the gaps on the rear surface of the insulated box 1a. The vacuum insulation material 100 is positioned to cover almost the entire top surface of the refrigerator compartment 2, the bottom surface of the vegetable compartment 6, and the sides and rear surfaces of the refrigerator compartment 2, the ice-making compartment 3, the upper freezer compartment 4, the lower freezer compartment 5, and the vegetable compartment 6.

[0111] Furthermore, in Figure 4, the vacuum insulation material 100 containing the organic gas adsorbent is installed in the voids inside the lower freezer door 5a and the vegetable compartment door 6a. The vacuum insulation material 100 is positioned to cover almost the entire front surface of the lower freezer compartment 5 and the front surface of the vegetable compartment 6. The foamed insulation material is filled into the voids around the vacuum insulation material 100 and into other voids where the vacuum insulation material 100 is not installed.

[0112] The vacuum insulation material 100 containing the organic gas adsorbent can be installed in one or more locations in the refrigerator 1, specifically in the gap between the inner box 1b and the outer box 1c of the insulated box 1a, and in the gap inside the insulated door. Preferably, the vacuum insulation material 100 containing the organic gas adsorbent is installed in one or more locations in the gap between the inner box 1b and the outer box 1c, specifically in the gap on the top surface of the insulated box 1a, the gap on the bottom surface of the insulated box 1a, the gaps on the left and right sides of the insulated box 1a, and the gap on the rear surface of the insulated box 1a. More preferably, the vacuum insulation material 100 is installed in the gaps across the entire surface of the insulated box 1a.

[0113] Furthermore, the vacuum insulation material 100 containing the organic gas adsorbent can be installed in one or more of the voids inside the insulated doors, specifically in the voids inside the refrigerator doors 2a and 2b, the ice maker door 3a, the upper freezer door 4a, the lower freezer door 5a, and the vegetable compartment door 6a. It is preferable that the vacuum insulation material 100 be installed in at least the void inside the lower freezer door 5a.

[0114] Furthermore, the vacuum insulation material 100 containing the organic gas adsorbent may be installed in one or more of the voids inside the insulating partition walls that separate storage compartments, for example, the void inside the insulating partition wall 28 installed between the refrigerator compartment 2 and the ice-making compartment 3 and the upper freezer compartment 4, the void inside the insulating partition wall 29 installed between the ice-making compartment 3 and the upper freezer compartment 4 and the lower freezer compartment 5, and the void inside the insulating partition wall 30 installed between the lower freezer compartment 5 and the vegetable compartment 6. It is preferable that the vacuum insulation material 100 be installed in at least the void inside the insulating partition wall 28.

[0115] The vacuum insulation material 100 containing the organic gas adsorbent may be placed in the gap between the inner box 1b and the outer box 1c, either closer to the inner box 1b (the lower temperature side) or closer to the outer box 1c (the higher temperature side). Placing the vacuum insulation material 100 closer to the inner box 1b allows it to be placed at a lower temperature, thus more efficiently capturing organic gases released from the outer packaging material 101. On the other hand, placing the vacuum insulation material 100 closer to the outer box 1c allows it to be fixed to the inner surface of the outer box 1c, making it easier to incorporate into the gap.

[0116] According to the refrigerator 1 described above, since it is equipped with a vacuum insulation material containing an organic gas adsorbent, the deterioration of insulation performance due to organic gases originating from the outer packaging material can be suppressed. Organic gases that were not immobilized with conventional adsorbents that adsorb low molecular weight gases are immobilized, making it possible to achieve a higher degree of vacuum and lower thermal conductivity than before. Therefore, it is possible to provide a refrigerator that consumes less power and is more energy-efficient than conventional refrigerators. In addition, since the organic gas adsorbent can be used in combination with a low molecular weight adsorbent, a higher degree of vacuum can be maintained. Thus, it is possible to provide a refrigerator in which the insulation performance of the vacuum insulation material is maintained over a long period of time. Because high insulation performance is obtained with a vacuum insulation material containing an organic gas adsorbent, it becomes possible to reduce the gap between the inner box and the outer box, which is advantageous for increasing the volume of the storage compartment and reducing the volume occupied by the insulated box body.

[0117] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are included as long as they do not depart from the technical scope. For example, the embodiments described above are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace some of the configurations of one embodiment with other configurations, or to add other configurations to the configuration of one embodiment. It is also possible to add other configurations, delete configurations, or substitute configurations for some of the configurations of one embodiment.

[0118] For example, in the refrigerator 1 shown in Figures 3 and 4, the lower freezer compartment 5 and vegetable compartment 6 can be provided as switchable compartments that can switch between a refrigeration temperature range of 1 to 6°C and a freezing temperature range of -20 to -18°C. Control to make the upper side a refrigerator compartment and the lower side a freezer compartment, or control to make the upper side a freezer compartment and the lower side a refrigerator compartment, or control to make the upper and lower sides the same temperature range is possible by controlling dampers, etc. In such cases, it is preferable to install an insulating wall 30 in which a vacuum insulating material 100 containing an organic gas adsorbent is embedded in a foamed insulating material.

[0119] Furthermore, the refrigerator 1 shown in Figures 3 and 4 is equipped with a refrigerator compartment 2, an ice-making compartment 3, an upper freezer compartment 4, a lower freezer compartment 5, and a vegetable compartment 6 as storage compartments, but the number, arrangement, and function of the storage compartments are not particularly limited. Also, the number, arrangement, and opening / closing method of each insulated door, the arrangement of the cooling mechanism for the storage compartments and the equipment related to the operation of the refrigerator, and the structure of the air passages for cooling the storage compartments are not particularly limited.

[0120] Furthermore, although the vacuum insulation material 100 containing the aforementioned organic gas adsorbent is installed in a household refrigerator 1, it may also be installed in other equipment, vehicles, buildings, etc. Examples of other equipment include commercial refrigerators, household freezers, commercial freezers, refrigerators, coolers, refrigerated display cases, refrigerated display cases, warmers, water heaters, insulated containers for logistics, cooler boxes, vending machines, etc. Examples of vehicles include refrigerated trucks and refrigerated freight trains. [Examples]

[0121] The present invention will be specifically described below with reference to examples, but the technical scope of the present invention is not limited thereto.

[0122] First, the adsorption performance of the adsorbents for organic gases was evaluated. Four types of activated carbon A to D, each with a different pore size distribution, were used as adsorbents. The adsorption rates of these adsorbents for organic gases in a vacuum were measured using a gas chromatography-mass spectrometer (GC / MS). The organic gases used were a mixture of hydrocarbons released from a heat-sealed layer made of low-density polyethylene. The results of the adsorption performance evaluation are shown in Table 1.

[0123] [Table 1]

[0124] In Table 1, the specific surface area is the value measured by the BET method. The pore volume fraction represents the ratio of the volume of micropores, mesopores, and macropores per 100% of the total pore volume of each adsorbent. The organic gas adsorption rate represents the time change in the amount of hydrocarbon mixture adsorbed per unit mass of the adsorbent at 25°C and a vacuum of 1 to 10 Pa. The pore volume fraction was measured using a specific surface area / pore distribution analyzer. The adsorption isotherm of nitrogen gas was determined by the gas adsorption method, and the pore volume and pore radius were analyzed based on the amount of adsorption to calculate each pore volume fraction.

[0125] As shown in Table 1, activated carbon A and activated carbon B had a mesoporous structure with well-developed mesopores, as the volume ratio of mesopores per 100% of the total pore volume was larger than that of micropores and macropores. Furthermore, they were confirmed to have a certain degree of specific surface area. Therefore, a high adsorption rate was obtained for organic gases released from the heat-sealed layer, even in a high-vacuum atmosphere.

[0126] On the other hand, activated carbon C had a microporous structure with a large micropore volume ratio per 100% of the total pore volume, compared to mesopores and macropores. Therefore, it was confirmed to have a certain level of specific surface area, but the adsorption rate of organic gases was low. Activated carbon D had a large macropore volume ratio per 100% of the total pore volume, and mesopores and micropores were not well developed, resulting in a small specific surface area and an organic gas adsorption rate below the detection limit.

[0127] Next, organic gases released from the heat-sealed layer were collected from inside the outer packaging of the vacuum insulation material and qualitatively analyzed using a gas chromatography-mass spectrometer (GC / MS). Table 2 shows representative organic gases released at high concentrations from the heat-sealed layer formed of low-density polyethylene. In Table 2, the molecular weight, melting point, and boiling point are literature values ​​for each organic gas. The boiling point is the value at atmospheric pressure.

[0128] [Table 2]

[0129] As shown in Table 2, from the heat-sealed layer formed of low-density polyethylene, decane (C) 10 H 22 ), Dodecane (C 12 H 26 ), tetradecane (C 14 H 30 ), hexadecane (C 16 H 34 ), Octadecan (C 18 H 38 ), Eikosan (C 20 H 42 Hydrocarbons, which are oligomers formed by the polymerization of ethylene monomers such as ), were detected. Only trace amounts of hydrocarbons with 9 or fewer carbon atoms, and hydrocarbons with 21 or more carbon atoms, were detected.

[0130] The hydrocarbons released from the heat-sealed layer formed of low-density polyethylene all have melting points below 40°C and are unlikely to solidify at room temperature. Furthermore, although their boiling points are high at atmospheric pressure, they are likely to exist as gases at vacuum levels of 1-10 Pa. Therefore, immobilizing these hydrocarbons by adsorbing them onto an adsorbent is considered effective in improving the thermal insulation performance of vacuum insulation materials.

[0131] Simulations based on molecular dynamics calculated the molecular sizes of these hydrocarbons in a vacuum, and the molecular chain lengths were calculated to be 1.3–2.5 nm. The molecular size of decane was 1.3 nm, and the molecular size of eicosane was 2.5 nm. Therefore, it is highly likely that conventional adsorbents used in vacuum insulation materials to adsorb low molecular weight substances such as oxygen and water vapor cannot efficiently adsorb organic gases released from the heat-sealed layer.

[0132] [Example 1] As Example 1, a vacuum insulation material containing activated carbon was prepared, and the insulation performance of the vacuum insulation material was evaluated. The activated carbon used had a specific surface area of ​​800 m². 2 Activated carbon A was used, with a volume fraction of 10% for micropores, 70% for mesopores, and 20% for macropores.

[0133] First, the adsorption performance of activated carbon A was evaluated. A gas barrier outer packaging material, with a heat-sealed layer made of low-density polyethylene, was placed in a vacuum chamber with adjustable vacuum levels. Inside the outer packaging material, 5 g of calcium oxide and 10 g of activated carbon A were placed.

[0134] Then, the chamber was evacuated to 0.5 Pa, and the valve was closed to seal the chamber. Subsequently, the time change of the pressure inside the chamber was measured over time using a vacuum gauge at 25°C. Based on the time change of pressure, the adsorption rate by activated carbon A was determined to be 1.0 × 10⁻⁶. -10 The value was mol / (min·g).

[0135] Next, a vacuum insulation material containing activated carbon A was prepared. Glass wool was cut to a length of 250 mm x width of 250 mm x thickness of approximately 50 mm and packaged in an outer packaging material with a heat-sealable layer made of low-density polyethylene. 10 g of calcium oxide and 10 g of activated carbon A were placed inside the outer packaging material. After vacuuming the inside of the outer packaging material, the outer packaging material was heat-sealed to create a sealed vacuum insulation material.

[0136] Next, the thermal insulation performance of the vacuum insulation material containing activated carbon A was evaluated. The initial thermal conductivity immediately after the fabrication of the vacuum insulation material and the thermal conductivity after the degradation test were measured using a thermal conductivity measuring device HC-070 (manufactured by Eiko Seiki Co., Ltd.). The degradation test was performed by placing the vacuum insulation material in a constant temperature bath adjusted to 70°C. The thermal conductivity after the degradation test was measured at 30 and 90 days. The measurement results of the thermal conductivity are shown in Table 3.

[0137] [Example 2] As Example 2, a vacuum insulation material containing activated carbon was prepared, and the insulation performance of the vacuum insulation material was evaluated. The activated carbon used had a specific surface area of ​​1000 m². 2 Activated carbon B was used, with a density of / g and a micropore volume fraction of 30%, a mesopore volume fraction of 60%, and a macropore volume fraction of 10%. The preparation of the vacuum insulation material and the evaluation of its insulation performance were carried out in the same manner as in Example 1, except that the type of activated carbon was changed. The results of the thermal conductivity measurement are shown in Table 3.

[0138] [Comparative Example 1] As Comparative Example 1, a vacuum insulation material containing activated carbon was prepared, and its insulation performance was evaluated. The activated carbon used had a specific surface area of ​​3000 m². 2 Activated carbon C was used, with a volume fraction of 95% for micropores, 4% for mesopores, and 1% for macropores. The preparation of the vacuum insulation material and evaluation of its insulation performance were carried out in the same manner as in Example 1, except that the type of activated carbon was changed. The measurement results of the thermal conductivity are shown in Table 3.

[0139] [Comparative Example 2] As Comparative Example 2, a vacuum insulation material without activated carbon was prepared, and its thermal insulation performance was evaluated. The preparation of the vacuum insulation material and the evaluation of its thermal insulation performance were carried out in the same manner as in Example 1, except that activated carbon was not used. The results of the thermal conductivity measurement are shown in Table 3.

[0140] [Table 3]

[0141] As shown in Table 3, Examples 1 and 2 exhibited lower initial thermal conductivity compared to Comparative Examples 1 and 2. Furthermore, the degradation rate of thermal conductivity after degradation tests relative to the initial thermal conductivity was significantly suppressed at 30 and 90 days. Organic gases released from the heat-sealed layer of the outer packaging material have larger molecular sizes compared to oxygen, water vapor, carbon dioxide, etc. Therefore, it is thought that adsorbents with well-developed micropores, such as Comparative Example 1, and adsorbents with fewer pores and a small specific surface area, such as Comparative Example 2, were unable to efficiently adsorb organic gases. It is thought that micropores and macropores have fewer adsorption sites capable of immobilizing hydrocarbons with 10 to 20 carbon atoms.

[0142] In contrast, in adsorbents with well-developed mesopores, such as those in Example 1 and Example 2, hydrocarbons with 10 to 20 carbon atoms can be adsorbed into the mesopores. Since a sufficiently large specific surface area is secured, it is thought that organic gases released from the heat-sealed layer of the outer packaging material are efficiently and abundantly adsorbed. Because the immobilization of organic gases by the adsorbent maintains a high degree of vacuum inside the outer packaging material, it can be said that higher thermal insulation performance than conventional methods can be sustained. [Explanation of Symbols]

[0143] 1. Refrigerator 1a Insulated box 1b Inner box 1c Outer box 2. Refrigerator compartment 3. Ice maker 4. Upper freezer compartment 5. Lower freezer compartment 6. Vegetable compartment 9a First Fan 9b Second Fan 14a 1st cooler 14b 2nd cooler 20 Compressors 28. Insulated partition wall 29. Insulated partition wall 30 Insulated partition wall 31 Control board 100 Vacuum Insulation Material 101 Outer packaging material 102 Core material 103 Adsorbent 111 Base material 112 Gas barrier layer 113 Heat-sealed layer

Claims

1. The device comprises an outer packaging material having gas barrier properties, a core material filled inside the outer packaging material, and an adsorbent contained inside the outer packaging material, wherein the adsorbent has a specific surface area of ​​500 m². ２ A vacuum insulation material having a density of 1 / g or more, being mesoporous with well-developed mesopores having a diameter of 2 nm or more and less than 50 nm, and containing a gas adsorbent capable of adsorbing organic gases originating from the outer packaging material.

2. A vacuum insulation material according to claim 1, The gas adsorbent is a vacuum insulation material in which the volume ratio of mesopores per 100 volume percent of the total pore volume is the largest among the volume ratio of micropores with a diameter of 2 nm or less, the volume ratio of mesopores with a diameter of 2 nm or more and less than 50 nm, and the volume ratio of macropores with a diameter of 50 nm or more and 100 nm or less.

3. A vacuum insulation material according to claim 1, A vacuum insulation material in which the gas adsorbent is formed from a carbon material.

4. A vacuum insulation material according to claim 1, The gas adsorbent is a vacuum insulating material that adsorbs hydrocarbons having 10 to 20 carbon atoms.

5. A vacuum insulation material according to claim 1, The gas adsorbent has an adsorption rate of hydrocarbons of 1.0 × 10⁻¹⁰ at a vacuum level of 1 Pa to 10 Pa. －１０ Vacuum insulation material with a concentration of mol / (min·g) or higher.

6. A vacuum insulation material according to claim 1, The aforementioned outer packaging material is a vacuum insulation material having a multilayer structure comprising a gas barrier layer that suppresses gas permeation and a heat-sealable layer that is heat-sealed when the outer packaging material is sealed.

7. A vacuum insulation material according to claim 6, A vacuum insulation material in which the heat-sealed layer is formed of polyethylene.

8. A vacuum insulation material according to claim 7, The gas adsorbent is a vacuum insulation material that adsorbs one or more of the following gases released by the heat-sealed layer: decane, dodecane, tetradecane, hexadecane, octadecane, and eicosane.

9. A refrigerator equipped with vacuum insulation, The vacuum insulation material comprises an outer packaging material having gas barrier properties, a core material filled inside the outer packaging material, and an adsorbent contained inside the outer packaging material, wherein the adsorbent has a specific surface area of ​​500 m². ２ A refrigerator comprising a gas adsorbent capable of adsorbing organic gases originating from the outer packaging material, having a density of 1 / g or more, and being mesoporous with well-developed mesopores having a diameter of 2 nm or more and less than 50 nm.

10. A refrigerator according to claim 9, The refrigerator comprises an insulated box that separates the outside from the inside, and an insulated door that opens and closes the opening of the insulated box. The vacuum insulation material is installed in one or more of the following locations in the refrigerator: the void on the top surface of the insulated box, the void on the bottom surface of the insulated box, the voids on the left and right sides of the insulated box, the void on the rear surface of the insulated box, and the void inside the insulated door.

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