JPWO2019021359A1 - Vacuum insulation material, insulation box, and method of manufacturing vacuum insulation material - Google Patents

Abstract

The vacuum heat insulating material includes a core material that holds a vacuum space, a hydroxide, and an outer packaging material that covers the core material and the hydroxide. The weight of the object is at least 0.01 times the weight of the core material. Further, the method for manufacturing a vacuum heat insulating material, a core material for holding a vacuum space, an oxide, a step of forming a sealed body by covering and sealing with an outer packaging material, a step of heat treatment of the sealed body, Decompressing and sealing the inside of the outer packaging material of the sealed body.

Description

  TECHNICAL FIELD The present invention relates to a vacuum heat insulating material, a heat insulating box, and a method for manufacturing a vacuum heat insulating material used as a heat insulating material of a refrigerator or the like.

  This kind of conventional vacuum heat insulating material has a configuration in which a core material and an adsorbent that adsorbs moisture or gas are covered with an outer packaging material, and the inside of the outer packaging material is hermetically sealed by reducing the pressure to near vacuum (for example, Patent Document 1). In such a vacuum heat insulating material, a decrease in the degree of vacuum inside the outer packaging material leads to a decrease in heat insulation performance. For this reason, in the vacuum heat insulating material of Patent Document 1, the core material is previously dried in a drying furnace before being inserted into the outer packaging material, so that the inside of the outer packaging material is decompressed and sealed, and then moisture released from the core material is reduced. , The degree of vacuum inside the outer packaging material is increased, and a decrease in heat insulation performance is suppressed.

JP 2004-286050 A

  In Patent Literature 1, drying is performed before the core material is inserted into the outer package material. However, the amount of water removed from the core material by drying in the drying furnace depends on the relative humidity in the drying furnace. Since the relative humidity in the drying furnace changes depending on the season, weather, and the like, the amount of water removed from the core also changes. Therefore, the amount of moisture released from the core material into the outer packaging material after the interior of the outer packaging material into which the core material has been inserted is reduced in pressure and fluctuated. As a result, there is a problem that the degree of vacuum inside the outer packaging material varies depending on the season, weather, and the like, and the thermal insulation performance of the vacuum thermal insulation material varies greatly.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a vacuum heat insulating material, a heat insulating box, and a method of manufacturing a vacuum heat insulating material with less variation in heat insulating performance.

  The vacuum heat insulating material according to the present invention includes a core material that holds a vacuum space, a hydroxide, and an outer packaging material that covers the core material and the hydroxide, and the interior of the outer packaging material is hermetically sealed by being decompressed. The weight of the hydroxide is at least 0.01 times the weight of the core material.

  Further, a heat insulating box according to the present invention includes the above vacuum heat insulating material.

  In addition, the method for manufacturing a vacuum heat insulating material according to the present invention includes a step of forming a sealed body by covering a core material for holding a vacuum space and an oxide with an outer packaging material to form a sealed body; And a step of sealing the inside of the outer packaging material by reducing the pressure.

  According to the present invention, since the weight of the hydroxide in the outer packaging material is 0.01 times or more the weight of the core material, it is possible to obtain a vacuum heat insulating material and a heat insulating box with less variation in heat insulating performance. In addition, since the core material is covered with the outer packaging material and then heat-treated, the core material can be dried uniformly without depending on the relative humidity of the heat treatment furnace, and the vacuum insulation material has less variation in heat insulation performance. Can be provided.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a vacuum heat insulating material according to Embodiment 1 of the present invention. It is a manufacturing process figure of the vacuum heat insulating material concerning Embodiment 1 of this invention. FIG. 3 is a cross-sectional view illustrating a schematic configuration of a vacuum heat insulating material to which an adsorbent 3 has been added in step S21 of the manufacturing process in FIG. 2. FIG. 4 is a diagram showing a relationship between the thermal conductivity and the weight ratio of calcium hydroxide to the core material weight under the conditions of Example 3 in the vacuum heat insulating material according to Embodiment 1 of the present invention. It is sectional drawing which shows schematic structure of the heat insulation box which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
A vacuum heat insulating material according to Embodiment 1 of the present invention and a method of manufacturing the same will be described.

FIG. 1 is a sectional view showing a schematic configuration of the vacuum heat insulating material according to Embodiment 1 of the present invention. In the following drawings including FIG. 1, the dimensional relationships, shapes, and the like of the respective components may be different from actual ones. Specific dimensions and the like of each component should be determined in consideration of the following description.
As shown in FIG. 1, the vacuum heat insulating material 1 includes a core material 2, an adsorbent 3, a hydroxide 4, and an outer packaging material 5 covering these. The internal space of the outer packaging material 5 is sealed in a state where the degree of vacuum is reduced to about 1 Pa to 3 Pa. The vacuum heat insulating material 1 has a substantially rectangular flat plate shape as a whole.

  The core material 2 is used for the purpose of maintaining a vacuum space. As the core material 2, a fiber aggregate such as glass wool is used. Further, the fiber aggregate constituting the core material 2 may be formed by heating and pressing, may be hermetically sealed by using an encapsulating material, or may be bonded by a binder.

  The adsorbent 3 adsorbs gas or moisture inside the vacuum heat insulating material 1. The adsorbent 3 is used for adsorbing gas or moisture inside the vacuum heat insulating material 1 to maintain the degree of vacuum inside the vacuum heat insulating material 1. By maintaining the degree of vacuum inside the vacuum heat insulating material 1, it is possible to suppress an increase in thermal conductivity, that is, a decrease in heat insulation performance. As the adsorbent 3, for example, calcium oxide (CaO) is used. The adsorbent 3 may be silica gel or zeolite, or a combination thereof.

  The outer wrapping material 5 is an outer wrapping material 5 used for an existing vacuum heat insulating material, and is a laminated film having a multilayer structure. This multilayer structure has, for example, a structure in which a polyethylene layer, an aluminum-deposited ethylene-vinyl alcohol layer, an aluminum-deposited polyethylene terephthalate layer, and a nylon layer are laminated on the outermost layer in order from the core material 2 side. In addition, the outer packaging material 5 is not limited to the above configuration, and instead of aluminum deposition, alumina deposition or silica deposition may be used. The outer packaging material 5 only needs to have gas barrier properties.

The hydroxide 4 holds moisture released from the core material 2 by a heat treatment described later. The weight of the hydroxide 4 is at least 0.01 times the weight of the adsorbent 3 and the core 2. As the hydroxide 4, for example, calcium hydroxide (Ca (OH) ₂ ) is used. The hydroxide 4 may be magnesium hydroxide or aluminum hydroxide, or a combination thereof.

  Next, a manufacturing process of the vacuum heat insulating material 1 according to the first embodiment will be described.

FIG. 2 is a manufacturing process diagram of the vacuum heat insulating material according to Embodiment 1 of the present invention.
In the manufacturing process of the vacuum heat insulating material 1 according to the first embodiment, first, the core material 2, the adsorbent 3, and the oxide are covered with the outer packaging material 5 and sealed (step S11) to form a sealed body. The oxide is, for example, calcium oxide. Then, the sealed body is subjected to a heat treatment (step S12). The condition of the heat treatment is, for example, 100 ° C. for 2 hours. The condition of the heat treatment may be a condition under which moisture is released from the core material 2.

  By this heat treatment, the hydroxide 4 is generated by a chemical reaction between the water released from the core material 2 and the oxide. That is, the water released from the core 2 is retained by the hydroxide 4. The generated hydroxide 4 is, for example, calcium hydroxide.

  Next, a part of the outer packaging material 5 is opened (step S13). Then, the inside of the outer packaging material 5 in a partially opened state is reduced in pressure and sealed (step S14). That is, the inside of the outer packaging material 5 is reduced in pressure to a degree of vacuum of about 1 Pa to 3 Pa, and the opened portion is sealed by heat sealing or the like under the reduced pressure.

  Although the adsorbent 3 is covered with the outer packaging material 5 in step S11, a step of adding the adsorbent 3 into the outer packaging material 5 (step S21) may be provided between step S13 and step S14. Good. FIG. 3 shows a configuration in which the adsorbent 3 is further added.

FIG. 3 is a cross-sectional view illustrating a schematic configuration of a vacuum heat insulating material to which an adsorbent has been added in step S21 of the manufacturing process in FIG.
As shown in FIG. 3, when the adsorbent 3 a is added separately from the adsorbent 3, the adsorbent 3 a can be arranged in a region different from the region where the hydroxide 4 is arranged. By arranging the additional adsorbent 3a in a different region from the hydroxide 4, the outer packaging material 5 can be prevented from being bulky and being damaged from the inside. Note that the adsorbent 3 corresponds to the first adsorbent of the present invention, and the adsorbent 3a corresponds to the second adsorbent of the present invention.

  In the above steps, heat treatment is performed after the core material 2 is covered with the outer packaging material 5. Therefore, uniform drying of the core material 2 can be realized without depending on the relative humidity of the heat treatment furnace. Therefore, after the step of reducing the pressure inside the outer packaging material 5 in step S14, the amount of water released from the core material 2 does not vary depending on the season and weather. As a result, variations in the degree of vacuum inside the outer packaging material 5 in the individual vacuum heat insulating materials 1 are reduced, and variations in the thermal conductivity of the vacuum heat insulating material 1, that is, the heat insulating performance are reduced.

  Next, the vacuum heat insulating material 1 of the first embodiment was manufactured, and Examples 1 to 3 were compared with Comparative Examples 1 to 3. Hereinafter, the comparison result will be described.

<Example 1>
In Example 1, variations in the thermal conductivity of the vacuum heat insulating material 1 were examined. The samples and various conditions in Example 1 are as follows (1) to (5).
(1) Core material 2: Glass wool weighing 5 kg (2) Outer packaging material 5: Multilayer laminate in which a polyethylene layer, an aluminum-deposited ethylene-vinyl alcohol layer, an aluminum-deposited polyethylene terephthalate layer, and a nylon layer are laminated on the outermost layer Film (3) adsorbent 3: 100 g of calcium oxide (4) Heat treatment: 100 ° C. for 2 hours (5) Decompression treatment: Reduced pressure from 1 Pa to about 3 Pa

  Under the above conditions, ten vacuum heat insulating materials 1 were manufactured in the manufacturing process shown in FIG. Step S11 in FIG. 2 is a step in which the core material 2, the adsorbent 3, and the oxide are covered with the outer packaging material 5 and sealed, and the adsorbent 3 uses the calcium oxide (3). Therefore, it is an oxide. Therefore, after all, in step S11, the core material 2 and the oxide of (3) above are covered with the outer packaging material 5 and sealed. Further, the step of “adding an adsorbent” in step S21 is not performed. Then, after measuring the thermal conductivity of the vacuum heat insulating material 1, the vacuum heat insulating material 1 was opened, and the weight of calcium hydroxide as the hydroxide 4 was measured.

  Comparative Example 1 has the same samples and various conditions as those in (1) to (5) of Example 1. Then, in Comparative Example 1, after the core material 2 is covered with the outer packaging material 5, the heat treatment (4) is performed in an unsealed state. Next, the adsorbent 3 is arranged inside the outer packaging material 5 and the inside of the outer packaging material 5 is sealed.

  Ten vacuum heat insulating materials 1 were manufactured under the conditions of Comparative Example 1 described above. After the thermal conductivity of the vacuum heat insulating material 1 was measured, the vacuum heat insulating material 1 was opened, and the weight of calcium hydroxide as the hydroxide 4 was measured.

  Table 1 shows the results of comparing the average value, the standard deviation, and the weight of calcium hydroxide of the thermal conductivity of the ten vacuum heat insulating materials 1 manufactured under the respective conditions of Example 1 and Comparative Example 1. It is.

  As shown in Table 1, in Comparative Example 1, the average value of the thermal conductivity of the vacuum heat insulating material was 1.9 mW / (m · K), and the standard deviation was 0.3 mW / (m · K). Was. The weight of calcium hydroxide was 0.8 g, which was 0.00016 times the weight of the core material.

  On the other hand, in Example 1, the average value of the thermal conductivity of the vacuum heat insulating material 1 was 1.8 mW / (m · K), which was lower than Comparative Example 1. That is, Example 1 has higher heat insulation performance than Comparative Example 1. The standard deviation is 0.1 mW / (m · K), which is smaller than Comparative Example 1. That is, Example 1 has less variation in thermal conductivity than Comparative Example 1.

  In Example 1, the weight of calcium hydroxide was 106.8 g, which was 0.021 times the weight of the core material.

<Example 2>
Example 2 has the same samples and various conditions as those in (1) to (5) of Example 1. The difference between the second embodiment and the first embodiment is that, in the first embodiment, the “addition of adsorbent” step of step S21 is not performed, whereas the second embodiment is performed. Then, under the conditions of Example 2, ten vacuum heat insulating materials 1 were produced. After measuring the thermal conductivity of the vacuum heat insulating material 1, the vacuum heat insulating material 1 was opened and the weight of calcium hydroxide was measured.

  The sample used in Comparative Example 2 also has the same samples and various conditions as in (1) to (5) of Example 1. Then, in Comparative Example 2, the core material 2 and the adsorbent 3 were covered with the outer packaging material 5, and the heat treatment (5) was performed in an unsealed state. Next, the adsorbent 3a was additionally arranged, and the inside of the outer packaging material 5 was sealed under reduced pressure.

  Under the conditions of Comparative Example 2, ten vacuum heat insulating materials were produced. After measuring the thermal conductivity of the vacuum heat insulating material, the vacuum heat insulating material was opened and the weight of calcium hydroxide was measured.

  Table 2 shows the results of comparing the average value, the standard deviation, and the weight of calcium hydroxide of the thermal conductivity of the ten vacuum heat insulating materials produced under the respective conditions of Example 1 and Comparative Example 1. is there.

  As shown in Table 2, in Comparative Example 2, the average value of the vacuum heat insulating material was 1.8 mW / (m · K), and the standard deviation was 0.2 mW / (m · K). The weight of calcium hydroxide was 15.2 g, which was 0.0030 times the weight of the core material.

  On the other hand, in Example 2, the average value of the thermal conductivity of the vacuum heat insulating material 1 was 1.7 mW / (m · K), which was lower than the comparative example. That is, Example 2 has higher heat insulation performance than Comparative Example 2. Further, the standard deviation is 0.1 mW / (m · K), which is smaller than Comparative Example 2. That is, Example 2 has less variation in thermal conductivity than Comparative Example 2.

  In Example 2, the weight of calcium hydroxide was 120.4 g, which was 0.024 times the weight of the core material.

<Example 3>
In the third embodiment, the conditions (1), (2), (4) and (5) of the first embodiment are the same. Then, the adsorbent 3 was made of calcium oxide, and the amount of calcium oxide was increased by 10 g from 10 g to 100 g, and 10 pieces of the vacuum heat insulating material 1 were produced in the manufacturing process shown in FIG. In other words, ten vacuum heat insulating materials 1 are produced using the adsorbent 3 of 10 g of calcium oxide, and ten vacuum heat insulating materials 1 are produced using the adsorbent 3 of 20 g of calcium oxide. In addition, the process of “addition of adsorbent” in step S21 of FIG. 2 is not performed. Then, after measuring the thermal conductivity of each of the vacuum heat insulating materials produced as described above, the vacuum heat insulating material 1 was opened, and the weight of calcium hydroxide as the hydroxide 4 was measured. FIG. 4 plots the relationship between “thermal conductivity” and “weight ratio of calcium hydroxide to core material weight” for each vacuum heat insulating material 1.

  FIG. 4 is a diagram showing the relationship between the thermal conductivity and the weight ratio of calcium hydroxide to the core material weight under the conditions of Example 3 in the vacuum heat insulating material according to Embodiment 1 of the present invention. In FIG. 4, the horizontal axis represents the weight ratio of calcium hydroxide to the weight of the core material [times], and the vertical axis represents the thermal conductivity [mW / (m · K)]. In FIG. 4, clusters of plot points roughly aligned in the vertical direction are plot points when calcium oxide is the same amount, and are plot points when 10 g, 20 g,... ing.

  As shown in FIG. 4, a vacuum heat insulating material in which the weight of calcium hydroxide is 0.01 times or more the weight of the core material 2 has a small variation in thermal conductivity and a small variation in heat insulating performance. The weight of the calcium hydroxide becomes 0.01 times or more the weight of the core material 2 when the amount of the calcium oxide as the adsorbent 3 is 50 g or more.

  Generally, the water content held by the core material 2 before the heat treatment is at most 0.005 times the weight of the core material. The mass per molecule of calcium hydroxide is about four times the mass per molecule of water. Therefore, if the weight of the calcium hydroxide is 0.01 times or more of the weight of the core material obtained by integrating “0.005” and “4”, almost all of the water released from the core material 2 becomes hydroxylated. It will be held by calcium. That is, the vacuum heat insulating material 1 in which the weight of the calcium hydroxide is 0.01 times or more the weight of the core material 2 is the amount of water released from the core material 2 after the inside of the outer packaging material 5 is sealed under reduced pressure. Does not fluctuate. Then, since the amount of moisture released from the core material 2 after the inside of the outer packaging material 5 is sealed under reduced pressure does not fluctuate, there is little variation in the degree of vacuum inside the outer packaging material 5 and little variation in heat insulation performance. 1 can be obtained.

  Here, referring to Example 1 described above, the weight of the calcium hydroxide is 0.021 times the weight of the core material 2, and the weight of the calcium hydroxide in Example 2 is 0.024 times, which is 0.01 times or more. The vacuum heat insulating material 1 which is included in the range and has little variation in the heat insulating performance is obtained.

  The lower limit of the weight ratio of calcium hydroxide to the weight of the core material is 0.01 times or more as described above, but the upper limit is 0.1 times. The upper limit is set to 0.1 times for the following reason. That is, if it is larger than 0.1 times, the heat insulation performance is reduced, and the cost is increased, so that it cannot be industrially implemented.

Embodiment 2 FIG.
FIG. 5 is a cross-sectional view illustrating a schematic configuration of the heat insulating box according to Embodiment 2 of the present invention.
As shown in FIG. 5, the heat insulating box 100 is used as a housing of a refrigerator or the like that requires high heat insulating performance. The heat insulation box 100 has an inner box 110 and an outer box 120. The vacuum heat insulating material 1 described in the first embodiment is arranged in the space between the inner box 110 and the outer box 120, and performs heat insulation between the inner box 110 and the outer box 120. The position where the vacuum heat insulating material 1 is disposed is, for example, a position that is in close contact with the outer wall surface 110a of the inner box 110, and is disposed at a position where heat insulation can be performed between the inner box 110 and the outer box 120. Then, in the space between the inner box 110 and the outer box 120, portions other than the vacuum heat insulating material 1 are filled with urethane foam heat insulating material.

  As described above, the heat insulating box 100 is provided with the vacuum heat insulating material 1 having a small variation in thermal conductivity. Thereby, variation in the heat insulating performance of the heat insulating box 100 can be reduced. In a refrigerator or the like provided with the heat insulating box 100, power consumption is reduced.

  Further, the vacuum heat insulating material 1 has higher heat insulating performance than the urethane foam heat insulating material 130 and the like. For this reason, the heat insulating box 100 can obtain higher heat insulating performance than the heat insulating box 100 using only the urethane foam heat insulating material 130. Here, the configuration in which the space between the inner box 110 and the outer box 120 is filled with the urethane foam insulating material 130 is shown, but the vacuum heat insulating material 1 has higher heat insulation than the urethane foam heat insulating material 130 and the like. The urethane foam insulation 130 may be omitted because of its performance.

  Further, in the above description, the vacuum heat insulating material 1 is in close contact with the outer wall surface 110a of the inner box 110, but the vacuum heat insulating material 1 may be in close contact with the inner wall surface 120a of the outer box 120. Further, by using a spacer or the like, the vacuum heat insulating material 1 may be arranged in the space between the inner box 110 and the outer box 120 so as not to be in close contact with both the inner box 110 and the outer box 120.

  In the above description, illustration and description of parts equivalent to those of the heat insulating box 100 used for a general refrigerator or the like are omitted.

  Further, the vacuum heat insulating material according to the present invention is not limited to the above-described embodiment, but can be variously modified. The above-described embodiments and modified examples can be implemented in combination with each other.

  Further, in the above-described second embodiment, the configuration in which the vacuum heat insulating material 1 is used in the heat insulating box of the refrigerator provided with a cold heat source (not shown) has been described as an example, but the present invention is not limited to this. The vacuum heat insulating material 1 can also be used in a heat insulating box of a warm storage provided with a heat source, a heat insulating box without a cold heat source and a heat source, for example, a cooler box or the like. Further, the vacuum heat insulating material 1 may be used not only as a heat insulating box but also as a heat insulating member of a cooling device or a heating device such as an air conditioner, a vehicle air conditioner, and a water heater. Further, the shape of the vacuum heat insulating material 1 is not limited to a predetermined shape that cannot be deformed, and may be a shape that can be deformed. As a material using the vacuum heat insulating material 1 having a deformable shape, for example, a heat insulating bag or a heat insulating container having an outer bag and an inner bag is applicable.

  DESCRIPTION OF SYMBOLS 1 Vacuum insulation material, 2 core materials, 3 adsorbents, 4 hydroxides, 5 outer packaging materials, 100 heat insulation boxes, 110 inner boxes, 110a outer wall surfaces, 120 outer boxes, 120a inner wall surfaces, 130 urethane foam insulation materials.

Claims (10)

A core material for holding a vacuum space,
Hydroxide,
An outer packaging material for covering the core material and the hydroxide,
The inside of the outer packaging material is decompressed and sealed,
A vacuum heat insulating material, wherein the weight of the hydroxide is at least 0.01 times the weight of the core material.   2. The vacuum heat insulating material according to claim 1, wherein the hydroxide is calcium hydroxide.   The vacuum heat insulating material according to claim 1 or 2, wherein the outer packaging material is further coated with an adsorbent that adsorbs moisture.   The vacuum heat insulating material according to claim 3, wherein the adsorbent is calcium oxide.   The vacuum heat insulator according to any one of claims 1 to 4, wherein the core material is a fiber aggregate.   The vacuum heat insulating material according to claim 5, wherein the fiber aggregate is glass wool.   An insulating box provided with the vacuum insulating material according to claim 1. A step of forming a sealed body by covering and sealing the core material holding the vacuum space and the oxide with an outer package material,
Heat-treating the sealed body,
And decompressing and sealing the inside of the outer packaging material of the sealed body.   9. The method of manufacturing a vacuum heat insulating material according to claim 8, wherein in the step of forming the sealed body, a first adsorbent for adsorbing moisture is further covered with the outer packaging material and sealed.   The production of a vacuum heat insulating material according to claim 8 or 9, further comprising a step of adding a second adsorbent to the inside of the outer packaging material between the step of heating and the step of sealing under reduced pressure. Method.

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