TWI659177B - Vacuum insulation material, insulation box and manufacturing method of vacuum insulation material - Google Patents

Abstract

The vacuum insulation material of the present invention comprises: a core material composed of a fiber assembly and maintaining a vacuum space, a hydroxide, and an outer covering material covering the core material and the hydroxide; wherein the inside of the outer covering material is decompressed and then sealed; The weight of the hydroxide is 0.01 times or more the weight of the core material. In addition, a method for manufacturing a vacuum insulation material includes a step of forming a sealed body by covering and sealing a core material, an oxide, and a first adsorbent that adsorbs moisture in a vacuum space with an outer cover; A step of performing a heat treatment; and a step of decompressing and sealing the inside of the outer casing of the sealing body.

Description

Vacuum insulation material, insulation box and manufacturing method of vacuum insulation material

The present invention relates to a method for manufacturing a vacuum insulation material, a heat insulation box, and a vacuum insulation material for use as a heat insulation material such as a refrigerator.

Such a conventional vacuum insulation material has a structure in which a core material is covered with an outer cover material, an adsorbent that absorbs moisture or gas, and the inside of the outer cover material is decompressed to close to a vacuum and sealed (for example, refer to Patent Document 1). As for such a vacuum insulation material, a decrease in the internal vacuum degree of the outer cover material is associated with a decrease in the heat insulation performance. Therefore, in the vacuum insulation material of Patent Document 1, the core material is dried in a drying furnace before being inserted into the outer casing, and the inside of the outer casing is decompressed and sealed to reduce the moisture released from the core material. , And increase the internal vacuum of the outer material, and suppress the reduction of thermal insulation performance.

[Advanced technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-286050

Patent Document 1 describes that the core material is dried before the core material is inserted into the outer cover 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. Because the relative humidity in the drying oven will vary according to the season The amount of water removed from the core material also changes due to changes in weather and weather. Therefore, after the inside of the outer casing that has been inserted into the core material is decompressed and sealed, the amount of water released from the core material out of the outer casing also changes. As a result, the degree of vacuum inside the outer packaging material changes according to the season, weather, and the like, which causes a problem that the thermal insulation performance of the vacuum insulation material becomes large.

The present invention has been made to solve the problems as described above, and an object thereof is to provide a vacuum insulation material, a heat insulation box, and a method for manufacturing a vacuum insulation material with little variation in heat insulation performance.

The vacuum insulation material of the present invention comprises: a core material composed of a fiber assembly and maintaining a vacuum space, a hydroxide, and an outer covering material covering the core material and the hydroxide; wherein the inside of the outer covering material is decompressed and then sealed; The weight of the hydroxide is 0.01 times or more the weight of the core material.

The thermal insulation box of the present invention includes the vacuum insulation material described above.

In addition, the method for manufacturing a vacuum insulation material according to the present invention includes a step of forming a sealed body by covering and sealing a core material, an oxide, and a first adsorbent that adsorbs moisture in a vacuum space with an outer covering material. A step of applying heat treatment to the sealing body; and a step of decompressing and sealing the inside of the outer material of the sealing body.

According to the present invention, since the hydroxide weight in the outer casing is 0.01 times or more the weight of the core material, it is possible to provide a vacuum insulation material and a heat insulation box with little variation in heat insulation performance. In addition, since the core material is subjected to heat treatment after being coated with an outer material, it does not depend on the relative humidity of the heat treatment furnace, and the core material can be realized. If the material is uniform and dry, a method for manufacturing a vacuum insulation material with little change in insulation performance can be provided.

1‧‧‧Vacuum insulation material

2‧‧‧ core material

3‧‧‧ adsorbent

4‧‧‧ hydroxide

5‧‧‧ Outsourcing

100‧‧‧ Adiabatic Box

110‧‧‧Inner box

110a‧‧‧outer wall surface

120‧‧‧ Outer Box

120a‧‧‧Inner wall surface

130‧‧‧ foamed urethane insulation

Fig. 1 is a sectional view showing a schematic configuration of a vacuum heat insulating material according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the vacuum insulation material according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a schematic configuration of a vacuum heat insulating material with an adsorbent 3 added in step S21 in the manufacturing steps of FIG. 2.

FIG. 4 is a graph showing the relationship between the thermal conductivity and the weight ratio of calcium hydroxide to the weight of the core material in the vacuum insulation material according to the first embodiment of the present invention under the conditions of Example 3. FIG.

Fig. 5 is a sectional view showing a schematic configuration of an insulation box according to a second embodiment of the present invention.

Embodiment 1.

The vacuum heat insulating material and its manufacturing method according to the first embodiment of the present invention will be described.

Fig. 1 is a sectional view showing a schematic configuration of a vacuum heat insulating material according to a first embodiment of the present invention. In addition, in all the following drawings including FIG. 1, the dimensional relationships and shapes of related constituent members may be different from the actual situation. The specific dimensions of each component should be clearly judged after taking into account the following description.

As shown in FIG. 1, the vacuum insulation material 1 includes a core material 2, an adsorbent 3, a hydroxide 4, and an outer cover material 5 covering the core material. The interior space of the exterior material 5 Sealing is performed under reduced pressure to a vacuum of about 1 Pa to 3 Pa. The vacuum heat insulating material 1 has a substantially rectangular and flat plate shape as a whole.

The core material 2 is used for the purpose of maintaining a vacuum space. The core material 2 is a fiber aggregate such as glass wool. In addition, the fiber assembly system constituting the core material 2 may be one subjected to heat and pressure molding, may be sealed using an inner packaging material, or may be bonded using a bonding agent.

The adsorbent 3 adsorbs gas or moisture inside the vacuum insulation material 1. The adsorbent 3 is used for the purpose of adsorbing the gas or moisture inside the vacuum insulation material 1 and maintaining the vacuum degree inside the vacuum insulation material 1. By maintaining the internal vacuum degree of the vacuum insulation material 1, the increase in thermal conductivity can be suppressed, and the decrease in thermal insulation performance can be suppressed. As the adsorbent 3, for example, calcium oxide (CaO) is used. The adsorbent 3 may be silica gel or zeolite, or a combination of these.

The outer cover material 5 is an outer cover material 5 used for a conventional vacuum insulation material, and forms a laminated film having a multilayer structure. This multilayer structure has, for example, a laminated layer in order from the core material 2 side: a polyethylene layer, an aluminum-evaporated ethylene-vinyl alcohol layer, an aluminum-evaporated polyethylene terephthalate layer, and an outermost layer laminated with a nylon layer. The construction. In addition, the outer cover material 5 is not limited to the above-mentioned structure, and instead of aluminum vapor deposition, aluminum oxide vapor deposition or silicon dioxide vapor deposition may be used instead. The outer cover material 5 is sufficient as long as it has gas barrier properties.

The hydroxide 4 retains the moisture released from the core material 2 by the heat treatment described later. The weight of the hydroxide 4 is 0.01 times or more the weight of the adsorbent 3 and the core material 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, the manufacturing of the vacuum insulation material 1 according to the first embodiment Manufacturing steps are explained.

FIG. 2 is a manufacturing process diagram of the vacuum heat insulating material according to the first embodiment of the present invention.

In the manufacturing process of the vacuum insulation material 1 of the first embodiment, first, the core material 2, the adsorbent 3, and the oxide are covered and sealed with an outer cover material 5 (step S11) to form a sealed body. The oxide is, for example, calcium oxide. Then, the sealing body is subjected to a heat treatment (step S12). The conditions of the heat treatment are, for example, 100 ° C. for 2 hours. The conditions for the heat treatment may be any conditions as long as moisture is released from the core material 2.

By this heat treatment, it is convenient to use the water released from the core material 2 to chemically react with the oxide to generate hydroxide 4. That is, the water released from the core material 2 is held by the hydroxide 4. The produced hydroxide 4 is, for example, calcium hydroxide.

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

In addition, although the adsorbent 3 is covered with the outer cover material 5 in step S11, between step S13 and step S14, you may further include the step of adding the adsorbent 3 into the outer cover material 5 (step S21). The state configuration in which the adsorbent 3 is further added is shown in Fig. 3 below.

FIG. 3 is a cross-sectional view showing a schematic configuration of a vacuum insulation material in which the adsorbent is added in step S21 in the manufacturing step shown in FIG. 2.

As shown in FIG. 3, when the adsorbent 3a is added in addition to the adsorbent 3, the adsorbent 3a may be disposed in a region other than the region where the hydroxide 4 is disposed. area. If the additional adsorbent 3a is disposed in a region other than the hydroxide 4, the device will not be bulky and the outer cover material 5 can be prevented from being damaged externally. 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, the core material 2 is subjected to heat treatment after being covered with the outer material 5. Therefore, the core material 2 can be dried uniformly without depending on the relative humidity of the heat treatment furnace. Therefore, in step S14, the amount of water released from the core material 2 after the pressure reduction and sealing step inside the outer cover material 5 does not change depending on the season and weather. As a result, the variation in the degree of vacuum inside the outer cover 5 of each vacuum insulation material 1 is reduced, and the variation in the thermal conductivity (that is, the insulation performance) of the vacuum insulation material 1 is reduced.

Next, a vacuum insulation material 1 according to the first embodiment was produced, and the comparison between Examples 1 to 3 and Comparative Examples 1 to 3 was performed. The comparison results are described below.

<Example 1>

In Example 1, a change in the thermal conductivity of the vacuum insulation material 1 was investigated. The samples and various conditions of Example 1 are as follows (1) to (5):

(1) Core material 2: 5kg glass wool

(2) Outer material 5: Multi-layer structure laminated film composed of a polyethylene layer, an aluminum-evaporated ethylene-vinyl alcohol layer, an aluminum-evaporated polyethylene terephthalate layer, and an outermost nylon layer

(3) Adsorbent 3: 100g calcium oxide

(4) Heat treatment: 100 ° C, 2 hours

(5) Decompression treatment: vacuum degree reduced to about 1Pa ~ 3Pa

Make 10 according to the above conditions and according to the manufacturing steps shown in FIG. 2 Sheet vacuum insulation material 1. In addition, step S11 shown in FIG. 2 is a step of covering and sealing the core material 2, the adsorbent 3, and the oxide with the outer covering material 5. However, because the adsorbent 3 is the calcium oxide described in (3) above, the adsorbent 3 is Is an oxide. Therefore, as a result, step S11 is a step of covering and sealing the core material 2 and the oxide of (3) with the outer cover material 5. In addition, the "adsorbent addition" step of step S21 is not performed. Then, after measuring the thermal conductivity of the vacuum insulation material 1, the vacuum insulation material 1 was unsealed, and the weight of calcium hydroxide belonging to the hydroxide 4 was measured.

Comparative Example 1 has the same samples and various conditions as those in (1) to (5) of Example 1. On the other hand, in Comparative Example 1, after the core material 2 was covered with the outer cover material 5, the heat treatment (4) described above was performed in an unsealed state. Next, the adsorbent 3 is placed inside the outer cover 5 and the inside of the outer cover 5 is sealed.

According to the conditions of Comparative Example 1 described above, 10 pieces of vacuum insulation material 1 were produced. After performing the measurement of the thermal conductivity of the vacuum insulation material 1, the vacuum insulation material 1 was unsealed, and the weight of calcium hydroxide belonging to the hydroxide 4 was measured.

Table 1 shows the comparison results of the average value of thermal conductivity, standard deviation, and the weight of calcium hydroxide of 10 vacuum insulation materials 1 made according to various conditions in Example 1 and Comparative Example 1.

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

In contrast, the average value of the thermal conductivity of the vacuum insulation material 1 of Example 1 was 1.8 mW / (m · K), which was lower than that of Comparative Example 1. That is, the thermal insulation performance of Example 1 is higher than that of Comparative Example 1. The standard deviation is 0.1 mW / (m · K), which is smaller than that of Comparative Example 1. That is, the variation in the thermal conductivity of Example 1 is smaller than that of Comparative Example 1.

The weight of calcium hydroxide in Example 1 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 the above (1) to (5) of Example 1. The difference between the embodiment 2 and the embodiment 1 is that the above-mentioned embodiment 1 does not perform the "adsorbent addition" step of step S21, but the embodiment 2 does. Then, on the basis of the conditions of Example 2, 10 pieces of vacuum insulation material 1 were produced. After performing the measurement of the thermal conductivity of the vacuum insulation material 1, the vacuum insulation material 1 was opened and the weight of calcium hydroxide was measured.

The samples used in Comparative Example 2 also had the same samples and various conditions as those in the above (1) to (5) of Example 1. On the other hand, in Comparative Example 2, the core material 2 and the adsorbent 3 were covered with an outer cover material 5 and then the above-mentioned (5) heat treatment was performed in an unsealed state. Next, an adsorbent 3a is additionally disposed, and the inside of the outer cover 5 is sealed under reduced pressure.

Based on the conditions of this Comparative Example 2, 10 pieces of vacuum insulation materials were produced. After performing the measurement of the thermal conductivity of the vacuum insulation material, the vacuum insulation material was unsealed, and the weight of calcium hydroxide was measured.

Table 2 shows the comparison results of the average thermal conductivity, standard deviation, and weight of calcium hydroxide of 10 vacuum insulation materials made in Example 1 and Comparative Example 1 under various conditions.

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

In contrast, the average value of the thermal conductivity of the vacuum insulation material 1 of Example 2 was 1.7 mW / (m · K), which was lower than that of Comparative Example 1. That is, the thermal insulation performance of Example 2 is higher than that of Comparative Example 2. The standard deviation is 0.1 mW / (m · K), which is smaller than that of Comparative Example 2. That is, the variation in the thermal conductivity of Example 2 is smaller than that of Comparative Example 2.

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

<Example 3>

Example 3 has the same conditions as those of (1), (2), (4), and (5) of Example 1. Next, the adsorbent 3 is made of calcium oxide, and 10 pieces of vacuum insulation material 1 are produced in accordance with the manufacturing steps shown in FIG. 2 using each amount of calcium oxide by increasing the amount of calcium oxide from 10 g to 100 g from 10 g. That is, 10 pieces of vacuum insulation material 1 are made according to the composition using 10 g of calcium oxide as the adsorbent 3, and 10 pieces of vacuum insulation material 1 are made according to the composition using 20 g of calcium oxide as the adsorbent 3. In addition, the "adsorbent addition" step of step S21 shown in FIG. 2 is not performed. Then, after measuring the thermal conductivity of each of the vacuum insulation materials produced as described above, the vacuum insulation material 1 was opened, and the weight of calcium hydroxide belonging to the hydroxide 4 was measured. Then, for each vacuum insulation material 1, the "thermal conductivity" and "calcium hydroxide with respect to the core" The relationship between the weight ratio of the material weight and the weight ratio was plotted, and the results are shown in FIG. 4.

FIG. 4 is a graph showing the relationship between the thermal conductivity and the weight ratio of calcium hydroxide to the weight of the core material under the conditions shown in Example 3 of the vacuum insulation material according to Embodiment 1 of the present invention. In FIG. 4, the weight ratio [times] of the horizontal axis calcium hydroxide to the weight of the core material, and the thermal conductivity of the vertical axis [mW / (m · K)]. Moreover, in FIG. 4, the drawing points are arranged in the longitudinal direction to form the drawing points belonging to the same amount of calcium oxide, and from the left, the drawing points in the case of 10g, 20g, ‧‧, 100g.

As shown in FIG. 4, a vacuum insulation material having a calcium hydroxide weight of 0.01 times or more the weight of the core material has less variation in thermal conductivity and thermal insulation performance. However, the weight of calcium hydroxide is 0.01 times or more of the weight of the core material 2, which appears only when the calcium oxide of the adsorbent 3 reaches 50 g or more.

Generally, the moisture retained by the core material 2 before the heat treatment is 0.005 times the maximum weight of the core material. The mass per molecule of calcium hydroxide is about 4 times the mass per molecule of water. Therefore, if the weight of calcium hydroxide multiplied by "0.005" and "4" is more than 0.01 times the weight of the core material, it means that almost all the water released from the core material 2 is retained by the calcium hydroxide. In other words, the vacuum insulation material 1 whose calcium hydroxide weighs 0.01 times or more the weight of the core material 2 can be said that the amount of water released from the core material 2 does not change after the inside of the outer material 5 is decompressed and sealed. Therefore, by decompressing and sealing the inside of the outer casing 5, the amount of water released from the core material 2 remains unchanged, and the vacuum insulation material 1 with less variation in the degree of internal vacuum and less variation in thermal insulation performance of the outer casing 5 can be obtained.

Here, if reference is made to the above Example 1, the weight of calcium hydroxide is 0.021 times the weight of the core material 2, and Example 2 is 0.024 times, both of which are within the range of 0.01 times or more, and a vacuum with little change in thermal insulation performance can be obtained. Thermal insulation material 1.

The lower limit value of the weight ratio of calcium hydroxide to the weight of the core material is 0.01 times or more, and the upper limit value is 0.1 times. The reason why the upper limit is set to 0.1 times is as follows. That is, if it is more than 0.1 times, the thermal insulation performance is reduced, and the cost is increased, which is not in accordance with industrial implementation.

Embodiment 2.

Fig. 5 is a cross-sectional view showing a schematic configuration of an insulation box according to a second embodiment of the present invention.

As shown in FIG. 5, the heat insulation box 100 requires high heat insulation performance, and is used as a housing such as a refrigerator. The heat insulation box 100 includes: an inner box 110 and an outer box 120. In the space between the inner box 110 and the outer box 120, the vacuum insulation material 1 described in Embodiment 1 is arranged, and heat insulation is performed between the inner box 110 and the outer box 120. The vacuum insulation material 1 is disposed at, for example, a position in close contact with the outer wall surface 110 a of the inner box 110, and is disposed at a position where the inner box 110 and the outer box 120 can be thermally insulated. Further, in the space between the inner box 110 and the outer box 120, a portion other than the vacuum heat insulating material 1 is filled with the foamed urethane heat insulating material 130.

In this way, the vacuum insulation material 1 having a small thermal conductivity variation is installed in the insulation box 100. This can reduce variations in the thermal insulation performance of the thermal insulation box 100. A refrigerator including the heat insulation box 100 can also reduce power consumption.

In addition, the vacuum thermal insulation material 1 has higher thermal insulation performance than the foamed urethane thermal insulation material 130 and the like. Therefore, the thermal insulation box 100 can obtain higher thermal insulation performance than the thermal insulation box 100 using only the foamed urethane thermal insulation material 130. In addition, here, the structure in which the foamed urethane insulation material 130 is filled in the space between the inner box 110 and the outer box 120 is illustrated. However, the vacuum insulation material 1 has a higher height than the foamed urethane insulation material 130 and the like. Thermal insulation Yes, the foamed urethane insulation material 130 may be omitted.

In the above description, the vacuum insulation material 1 is in close contact with the outer wall surface 110 a of the inner box 110, but the vacuum insulation material 1 may be in close contact with the inner wall surface 120 a of the outer box 120. In addition, by using a spacer or the like, the vacuum insulation material 1 is arranged in a space between the inner box 110 and the outer box 120 such that the inner box 110 and the outer box 120 are not in close contact with each other.

In addition, in the above description, the same parts as those of the thermal insulation box 100 used in a general refrigerator or the like are omitted from illustration and description.

In addition, the vacuum insulation material of the present invention is not limited to the above-mentioned embodiments, and various changes can be made. The above-mentioned embodiments and modified examples can be implemented in combination with each other.

In addition, the above-mentioned Embodiment 2 is a configuration example of a heat insulation box of a refrigerator including a cold and heat source (not shown), and the vacuum insulation material 1 is used, but the present invention is not limited to this. The vacuum insulation material 1 can also be used in, for example, a heat insulation box of a heat insulation storehouse including a warm heat source, and a heat insulation box (for example, a storage cabinet) that does not include a cold heat source and a warm heat source. In addition, the vacuum insulation material 1 is not only used in a heat insulation box, but can also be used as a heat insulation member such as an air conditioner, an air conditioner for a car, a hot water machine, or a warm device. The shape of the vacuum insulation material 1 is not limited to a predetermined shape that cannot be deformed, and may be a shape that can be deformed freely. In the case of using the vacuum heat-insulating material 1 having a freely deformable shape, the heat-insulating bag or the heat-insulating container including the outer bag and the inner bag is used.

Claims (8)

A vacuum insulation material includes: a core material, which is composed of fiber aggregates and maintains a vacuum space; hydroxide; and an outer covering material, which is covered with the core material and hydroxide; wherein the inside of the outer covering material is decompressed Resealed; the weight of the hydroxide is more than 0.01 times the weight of the core material. For example, the vacuum insulation material according to the scope of patent application No. 1 wherein the above-mentioned hydroxide is calcium hydroxide. For example, the vacuum insulation material of the first or second scope of the patent application, wherein the outer cover material is further coated with an adsorbent that adsorbs moisture. For example, the vacuum insulation material in the scope of the patent application No. 3, wherein the adsorbent is calcium oxide. For example, the vacuum insulation material according to the first or second application scope of the patent, wherein the above-mentioned fiber collection system is glass wool. A thermal insulation box comprises a vacuum thermal insulation material according to any one of claims 1 to 5. A method for manufacturing a vacuum insulation material, comprising the steps of: covering and sealing a core material, an oxide, and a first adsorbent that adsorbs moisture in a vacuum space with an outer cover to form a sealed body; and forming the seal. A step of subjecting the sealed body to a heat treatment after the body; and a step of decompressing and sealing the inside of the outer cover material of the sealed body after the heat treatment. For example, the method for manufacturing a vacuum thermal insulation material according to claim 7 includes a step of adding a second adsorbent to the inside of the outer cover between the heat treatment step and the pressure reduction and sealing step.