Vacuum insulation and refrigerators

Abstract

To provide a vacuum heat insulation material that can suppress intrusion of a gas from an external packing material of a vacuum heat insulation material and suppress deterioration in heat insulation performance by maintaining a degree of vacuum of the vacuum heat insulation material.SOLUTION: A vacuum heat insulation material 1 in the present invention includes: a core material 2; a gas adsorbent 3; and an external packing material 5 for encapsulating the core material 2 and the gas adsorbent 3 while reducing pressure. The external packing material 5 includes a polymer crystal. The polymer crystal is oriented in an inner surface direction of the external packing material 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vacuum insulation material and a refrigerator. [Background technology]

[0002] In recent years, from the viewpoint of reducing CO2 and saving energy, there is a demand for low power consumption in home appliances as well. For example, in refrigerators and refrigerated vehicles, improvement of insulation performance is required to achieve low power consumption. To improve insulation performance, vacuum insulation material is provided between the thin metal plate and the resin molded product that constitutes the wall surface of the refrigerator or refrigerated vehicle that needs to be insulated.

[0003] A vacuum insulation material comprises an outer packaging material (gas barrier film) that has the outer shell function of blocking the intrusion of outside air and maintaining an internal vacuum, and a core material inside the outer packaging material that has the function of retaining its shape mainly against atmospheric pressure and maintaining its initial insulating properties for a long period of time. Generally, a polymer film and a thin metal film layer are used in combination for the outer shell of the outer packaging material to block or suppress the intrusion of gas from the outside and maintain the internal vacuum to ensure insulating performance, but it is also important to prevent deterioration of the vacuum due to gas permeating from outside the outer packaging material, which is the main cause of deterioration over time due to long-term use.

[0004] Patent Document 1 describes a configuration in which a gas barrier layer 4 constituting a gas barrier laminate film 1 has an inorganic filler region 4a and a binder region 4b arranged adjacent to each other, the inorganic filler region 4a contains more inorganic filler components than the binder region 4b, and the binder region 4b contains more binder components than the inorganic filler region 4a. According to Patent Document 1, in the portion where the inorganic filler region 4a and the binder region 4b are adjacent to each other, the first layer 3 and the second layer 5 are bonded by the binder component of the binder region 4b, so that peeling between the first layer 3 and the second layer 5 is prevented in the portion overlapping with the inorganic filler region 4a. As a result, it is described that good gas barrier properties are obtained by the inorganic filler component, and even if the adhesiveness of the inorganic filler region 4a to the first layer 3 and the second layer 5 is low, peeling between the first layer 3 and the second layer 5 can be prevented, and a decrease in gas barrier properties can be prevented. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-138358 A Summary of the Invention [Problem to be solved by the invention]

[0006] During long-term use of refrigerators, etc., the degree of vacuum inside the vacuum insulation material may decrease due to gas permeating from the outside of the packaging material that constitutes the vacuum insulation material. In order to further improve the insulation performance of the vacuum insulation material, it is necessary to suppress the intrusion of this gas.

[0007] In the above-mentioned Patent Document 1, a layer made of an inorganic filler component and a binder component is provided as a gas barrier layer, but the inorganic filler-rich inorganic filler region 4a has reduced flexibility and is weak against bending, and there is a risk that the inorganic filler will break and the gas barrier properties will be reduced. Also, the binder-rich binder region 4b is strong against bending, but the inorganic filler is reduced, so there is a risk that the gas barrier properties will be insufficient.

[0008] In view of the above circumstances, the present invention aims to provide a vacuum insulation material that can prevent gas from entering through the outer packaging material of the vacuum insulation material, maintain the vacuum degree of the vacuum insulation material, and prevent deterioration of the insulation performance. [Means for solving the problem]

[0009] In order to solve the above problems, one aspect of the present invention is a core material, a gas adsorbent, and a gas adsorbent and a gas adsorbent. Arrival and an outer packaging material for sealing the agent under reduced pressure, 、 The polymer crystals are included, and the polymer crystals are an outer packaging material. The direction perpendicular to the direction of the permeating gas when the gas permeates through the Oriented in the in-plane direction The outer packaging material is a laminate in which a first layer constituting the outermost layer, a metal vapor deposition layer, a second layer, and a third layer are laminated in this order, the first layer being an olefin-based film or a polyester-based film, the second layer being polyether ether ketone or polyphenylene sulfide, the third layer being unoriented polypropylene or linear low-density polyethylene, and the metal vapor deposition layer being an aluminum vapor deposition layer. This is a vacuum insulation material characterized by the above.

[0010] Another aspect of the present invention for solving the above problem is a refrigerator including the vacuum insulation material of the present invention.

[0011] More specific configurations of the present invention are described in the claims. Effect of the Invention

[0012] According to the present invention, a vacuum insulation material can be provided that can suppress the intrusion of gas from the outer packaging material of the vacuum insulation material, maintain the degree of vacuum of the vacuum insulation material, and suppress deterioration of the insulation performance.

[0013] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a vacuum insulation material according to the present invention. [Diagram 2] Cross section of line AA in Figure 1 [Diagram 3] FIG. 1 is a schematic diagram showing an example of a refrigerator to which the vacuum insulation material of the present invention is applied; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the vacuum insulation material of the present invention will be described in detail. In this specification, "to" is used to mean that the numerical values ​​before and after it are the lower limit and upper limit. In the numerical ranges described in stages in this specification, the lower limit or upper limit described in one numerical range may be replaced with the lower limit or upper limit described in another stage. The lower limit or upper limit of the numerical range described in this specification may be replaced with a value shown in the examples.

[0016] Each member described in this specification may use a material selected from the group of materials constituting each member, either alone or in combination. Furthermore, each member or material described in this specification may be composed only of the materials described in this specification, or may contain other materials not described in this specification within the scope of not impairing the effects of the present invention.

[0017] The vacuum insulation material of the present invention is used, for example, in a vacuum insulation panel of a refrigerator together with urethane foam that constitutes the box of the refrigerator. A typical vacuum insulation panel is a plate with a thickness of 10 to 20 mm, and is used in a state where it is incorporated into the wall of the box of the refrigerator. After inserting an inner box into an outer box to which the vacuum insulation material is attached and combining them, a raw material mixture of urethane foam is injected and foam-molded to form an insulation wall.

[0018] Vacuum insulation panels are exposed to atmospheric pressure, the foaming pressure of urethane foam, and also to the atmosphere and the foaming gas atmosphere of urethane foam, and are also heated by heat generated during foaming of urethane foam. In order to ensure and maintain the required insulation performance, it is important to suppress the amount of heat transmitted through the substances that make up the core material, as well as to prevent deterioration of the degree of vacuum due to permeation gas from the outside of the outer packaging material and gas generated inside, which are the main causes of deterioration over time. Gases that cause deterioration of the degree of vacuum include air and water vapor that invade from the outside over time through pinholes in the metal thin film layer of the outer packaging material, gases generated from the constituent materials of urethane, water adsorbed by various constituent materials, unreacted raw materials, carbon dioxide gas as a by-product, and evaporation of various low-molecular-weight organic substances.

[0019] In the present invention, the above-mentioned outer packaging material is used which can suppress the gas permeating from the outside of the outer packaging material and can maintain the degree of vacuum of the vacuum insulation material. The configuration of the vacuum insulation material of the present invention will be described in detail below.

[0020] [Vacuum insulation material] Fig. 1 is a schematic cross-sectional view showing an example of a vacuum insulation material of the present invention. As shown in Fig. 1, the vacuum insulation material 1 of the present invention includes a core material 2, a gas adsorbent 3, and an outer packaging material 5 that seals the core material 2 and the gas adsorbent 3 under reduced pressure.

[0021] The core material 2 is a structure for maintaining the structure of the vacuum insulation material 1, and the core material 2 is wrapped in an outer packaging material 5 having gas barrier properties, and after the inside is evacuated, the outer packaging material 5 is heat-pressed to seal while maintaining the internal vacuum. It is preferable to use a material for the core material 2 that has the strength to maintain the thickness of the vacuum insulation material 1 even after the inside of the vacuum insulation material 1 is evacuated and has a small amount of degassing components. Examples of such materials include, but are not limited to, glass wool, resin nonwoven fabric, inorganic oxide porous particles, and resin porous particles.

[0022] The gas adsorbent 3 is a substance for adsorbing moisture that penetrates from the outside of the vacuum insulation material 1 or is generated from an internal member. Materials for the adsorbent 3 are preferably inorganic porous bodies such as silica gel, zeolite, and molecular sieve, and metal oxides such as aluminum oxide, calcium oxide, and magnesium oxide powder, but are not limited to these as long as they are capable of absorbing moisture.

[0023] The core material 2 and the gas adsorbent 3 are wrapped in an outer packaging material 5 having gas barrier properties, and after the inside is evacuated, the outer packaging material is heat-pressed to maintain the internal vacuum.

[0024] Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. As shown in Fig. 2, the outer packaging material 5 is a laminate in which a first layer 6, a metal vapor deposition layer 8, a second layer 7, and a third layer 9 are laminated in this order, and has a structure that prevents the intrusion of a permeable gas 4 into the vacuum insulation material 1 from the outside.

[0025] In the vacuum insulation material of the present invention, the outer packaging material 5 has polymer crystals 10, and the polymer crystals 10 are oriented in the in-plane direction of the outer packaging material 5. As shown in Fig. 2, the polymer crystals 10 are oriented in a direction perpendicular to the permeation direction (the direction of the arrow in Fig. 2) of the permeating gas 4 entering from outside the vacuum insulation material 1. With this configuration, the polymer crystals 10 can prevent the permeation of gas into the vacuum insulation material 1.

[0026] The degree of orientation of the polymer crystals 10 is preferably 1.5 or more and 5 or less. If the degree of orientation of the polymer crystals 10 is 1.5 or more, sufficient gas barrier properties can be ensured. Furthermore, if the degree of orientation of the polymer crystals 10 is greater than 5, the crystals become rigid and lose flexibility, which may reduce mechanical strength, so it is preferable to set the degree of orientation to 5 or less. The method for evaluating the orientation will be described in detail in the examples below.

[0027] It is preferable that the polymer crystal 10 is highly crystalline. The higher the crystallinity, the higher the gas barrier property. As with the degree of orientation, low crystallinity reduces the gas barrier property, while too high crystallinity reduces the flexibility of the packaging material and reduces its strength. Furthermore, in consideration of application to refrigerators, it is preferable that the polymer crystal 10 is made of a material with high resistance to cold and heat shocks.

[0028] As materials that satisfy the above-mentioned orientation degree, crystallinity, and thermal shock resistance, polyether ether ketone, polyphenylene sulfide, and polybutylene terephthalate are preferred.

[0029] The vacuum insulation material 1 of the present invention can achieve high gas barrier properties by orienting the polymer crystals 10 of the packaging material 5 in the in-plane direction of the packaging material. If inorganic crystals are used instead of the polymer crystals 10, flexibility is lost and mechanical strength is reduced. By using the polymer crystals 10, which are more flexible than inorganic crystals, it is possible to increase the gas barrier properties while maintaining sufficient mechanical strength even when the film thickness is increased.

[0030] The first layer 6 constituting the outermost layer of the packaging material 5 is preferably made of a polymer film that physically protects the metal deposition layer 8 disposed on the inside and has low gas solubility. Preferred materials for such a film include olefin-based films such as oriented polypropylene and polyester-based films such as polyethylene terephthalate.

[0031] The metal deposition layer 8 is preferably an aluminum-deposited polyethylene terephthalate film, but is not limited thereto.

[0032] The third layer 9 must function as a heat-sealing layer and must be a film that generates little gas when melted. Non-oriented polypropylene, linear low density polyethylene, and the like are preferred, but not limited to these.

[0033] [refrigerator] Fig. 3 is a schematic diagram showing an example of a refrigerator to which the vacuum insulation material of the present invention is applied. As shown in Fig. 3, refrigerator 11 of the present invention is configured by applying the vacuum insulation material 1 of the present invention to a vacuum insulation panel that constitutes the door of refrigerator 11. By using the above-mentioned vacuum insulation material 1 of the present invention, refrigerator 11 of the present invention can suppress permeation gas from outside the outer packaging material and maintain the degree of vacuum of the vacuum insulation material, thereby realizing low power consumption for a long period of time. EXAMPLES

[0034] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0035] [Preparation and evaluation of vacuum insulation materials of Examples 1 to 3 and Comparative Example 1] [Example 1] The packaging material of Example 1 was produced as follows, and a vacuum insulation material was produced using this, and the water vapor transmission rate, thermal conductivity, and degree of orientation were evaluated.

[0036] <Production of outer packaging material 5 of Example 1> An outer packaging material 5 having the configuration shown in Fig. 2 was produced. An oriented polypropylene film was used as the first layer 6, a polyethylene terephthalate film on which aluminum had been previously deposited was used as the metal deposition layer 8, a biaxially oriented highly crystalline polyether ether ketone film was used as the second layer 7, and a linear low-density polyethylene film was used as the third layer, and these were laminated using a urethane adhesive to obtain the outer packaging material 5.

[0037] <Evaluation of water vapor permeability of outer packaging material 5> The outer packaging material 5 having the above-mentioned structure was cut into a size of 12 cm x 12 cm, and three sides were heat-pressed. After about 10 g of calcium oxide, which is a desiccant, was added, the opening was heat-pressed and sealed. This was placed in a thermo-hygrostat at 40°C and 90% RH for a predetermined period of time, and the change in weight was measured, and the moisture permeation rate (g / m 2 / day) was calculated.

[0038] <Production of vacuum insulation material> A piece of glass wool was cut to 30 cm x 30 cm to serve as the core material 2, and wrapped in the above-mentioned outer packaging material 5. 10 g of calcium oxide and the above-mentioned adsorbent sheet were placed inside as the gas adsorbent 3. After creating a vacuum inside, the material was heat-sealed to produce the vacuum insulation material 1 of Example 1.

[0039] <Insulation evaluation> The thermal conductivity of the vacuum insulation material was measured immediately after production using a thermal conductivity measuring device using the GHP method manufactured by NETXSCH Co., Ltd. The results are shown in Table 1 below.

[0040] <Deterioration test> The vacuum insulation material thus produced was placed in a thermostatic chamber at 70° C., and the thermal conductivity was measured after 30 days and after 90 days. The results are shown in Table 1 below.

[0041] <Evaluation of the degree of orientation> A sample was cut out from the above-mentioned outer packaging film, embedded in epoxy resin, and the cross section of the film was processed with a microtome. Using this sample, the degree of orientation was evaluated by microscopic laser Raman spectroscopy. Specifically, the sample was set with the in-plane direction of the film at 0° and 90° to the polarization angle, and measurements were taken for each. The peak intensity derived from the C=O stretching band of each polyether ether ketone was measured as I 0° and I 90 ° and the orientation parameter is I 0° / I 90° The degree of orientation is also shown in Table 1. The apparatus and measurement conditions used for the laser Raman spectroscopy are as follows. Equipment: Laser Raman microscope (nanophoton) Conditions: Objective lens: x100 Beam diameter: 1μm Excitation wavelength: 532 nm

[0042] [Example 2] In Example 2, an outer packaging material 5 was manufactured in the same manner as in Example 1, except that biaxially oriented polyphenylene sulfide was used instead of the highly crystalline polyether ether ketone in the second layer 7 of the outer packaging material 5, and the water vapor permeability was evaluated. Also, as in Example 1, glass wool and calcium oxide were wrapped in the outer packaging material 5, the inside was evacuated, and then heat-sealed to produce a vacuum insulation material 1, and the thermal conductivity was measured initially and after a deterioration test. The results are shown in Table 1 below. Note that, when evaluating the degree of orientation, the peak due to the phenyl ring-S stretching band (1080 cm -1 The peak intensity around

[0043] [Example 3] In Example 3, the outer packaging material 5 was manufactured in the same manner as in Example 1, except that biaxially oriented polybutylene terephthalate was used instead of the highly crystalline polyether ether ketone of the second layer 7 of the outer packaging material 5, and the water vapor permeability was evaluated. In addition, the vacuum insulation material 1 was manufactured by wrapping it with glass wool and calcium oxide in the same manner as in Example 1, evacuating the inside, and then heat sealing it, and the thermal conductivity was measured at the initial stage and after the deterioration test. The results are shown in Table 1 below. In addition, when evaluating the degree of orientation, the peak intensity of the peak derived from the C=O stretch band was used.

[0044] [Comparative Example 1] In Comparative Example 1, the outer packaging material 5 was produced in the same manner as in Example 1, except that a biaxially oriented polyethylene-vinyl alcohol copolymer film was used instead of the highly crystalline polyether ether ketone of the second layer 7 of the outer packaging material 5. The water vapor permeability of the outer packaging material 5 was evaluated. Also, in the same manner as in Example 1, the material was wrapped in glass wool and calcium oxide, the inside was evacuated, and then heat-sealed to produce a vacuum insulation material 1, and the thermal conductivity was measured at the initial stage and after the deterioration test. The results are shown in Table 1 below.

[0045] [Table 1]

[0046] <Result> As shown in Table 1, the packaging materials of Examples 1 to 3 have water vapor transmission rates two orders of magnitude lower than the packaging material of Comparative Example 1, and are therefore extremely effective at preventing gas transmission. Also, it is clear that the increase in thermal conductivity (deterioration rate) of the vacuum insulation materials equipped with the packaging materials of Examples 1 to 3 can be significantly suppressed compared to that of the vacuum insulation materials using the ethylene-vinyl alcohol copolymer of Comparative Example 1.

[0047] As described above, it has been shown that the present invention can provide a vacuum insulation material that can suppress the intrusion of gas from outside the outer packaging material of the vacuum insulation material, maintain the vacuum degree of the vacuum insulation material, and suppress deterioration of the insulation performance.

[0048] The present invention is not limited to the above-mentioned embodiment, but includes various modified examples. For example, the above-mentioned embodiment has been described in detail to easily explain the present invention, and is not necessarily limited to those including all of the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Also, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0049] 1...vacuum insulation material, 2...core material, 3...gas adsorbent, 4...permeable gas, 5...outer packaging material, 6...first layer, 7...second layer, 8...metal vapor deposition layer, 9...third layer, 10...polymer crystal, 11...refrigerator.

Claims

1. A core material, a gas adsorbent, and an outer packaging material that seals the core material and the gas adsorbent under reduced pressure, The outer packaging material contains polymer crystals, The polymer crystals are oriented in an in-plane direction that is a direction perpendicular to the permeation direction of the permeating gas when the permeating gas permeates the outer packaging material, The outer packaging material is a laminate in which a first layer constituting an outermost layer, a metal vapor deposition layer, a second layer, and a third layer are laminated in this order, the first layer is an olefin-based film or a polyester-based film; the second layer is polyetheretherketone or polyphenylene sulfide; the third layer is unoriented polypropylene or linear low density polyethylene; A vacuum insulation material, characterized in that the metal vapor deposition layer is an aluminum vapor deposition layer.

2. 2. The vacuum insulation material according to claim 1, wherein the polymer crystals have a degree of crystal orientation of 1.5 or more.

3. 3. The vacuum insulation material according to claim 1, wherein the polymer crystals are polyether ether ketone.

4. 3. The vacuum insulation material according to claim 1, wherein the polymer crystals are polyphenylene sulfide.

5. 3. The vacuum insulation material according to claim 1, wherein the polymer crystals are polybutylene terephthalate.

6. A refrigerator comprising the vacuum insulation material according to claim 1 or 2.

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