TW201938373A - Vacuum heat-insulation material and heat-insulating box - Google Patents

Abstract

A vacuum heat-insulation material which comprises a core material for maintaining a vacuum space, an adsorbent for adsorbing moisture, and an encasing material that covers the core material and the adsorbent, the encasing material having been hermetically sealed so that the inside thereof is in a depressurized state, wherein the encasing material is configured of a surface-protective layer, a gas-barrier layer comprising at least two kinds of gas-barrier films, and a fusion-bonding layer, the at least two kinds of gas-barrier films having a difference therebetween in shrinkage through heating at 100 DEG C for 2 hours or longer of 2% or less.

Description

Vacuum insulation material and insulation box

The invention relates to a vacuum insulation material and a heat insulation box with a gas barrier layer in an outer cover.

In the past, it has been known that a vacuum insulation material formed by covering a core material for maintaining a vacuum space and an adsorbent for adsorbing water vapor with two outer covering materials and vacuum-sealing the inside of the outer covering material is used as a partition for a refrigerator or the like. Vacuum insulation for hot materials.

The outer cover material is composed of a surface protective layer, a gas barrier layer, and a heat-welded layer. The inside of the vacuum insulation material is maintained by the outer material, thereby reducing the thermal conductivity of the vacuum insulation material.

Patent Document 1 discloses a technique in which two inorganic vapor-deposited films constituting a gas barrier layer are brought into contact with each other and overlap with each other, as a known technique. In addition, Patent Document 2 discloses a technique of using a biaxially-stretched ethylene / vinyl alcohol film for a vacuum insulation material having a dry heat shrinkage ratio of 2% or less in the width direction and the length direction of the film.

Prior technical literature Patent literature:
Patent Document 1: Japanese Patent Application Publication No. 2012-219955 Patent Document 2: Japanese Patent Application Publication No. 2005-1240

Invent the problem to be solved

In the vacuum insulation material, the degree of vacuum is reduced due to the intrusion of water vapor into the interior, and the thermal conductivity is increased, resulting in low thermal insulation performance. The path of the water vapor intruding into the vacuum heat insulating material may be a path from the surface of the outer cover and a path of a heat-sealed layer formed by fusing two outer covers.

In the technique of Patent Document 1, the inorganic vapor-deposited layers of the gas barrier film are overlapped to prevent unevenness in vapor deposition and to suppress the intrusion of water vapor. Here, the vacuum heat insulating material is manufactured through a heating and drying step. Therefore, when the gas barrier film is shrunk and evaporation damage occurs, it is not possible to maintain the vacuum state inside the vacuum heat insulating material for a long period of time, and it is impossible to suppress an increase in thermal conductivity.

In addition, in the technology of Patent Document 2, the difference between the shrinkage ratios in the width direction and the length direction of each gas barrier film is limited to suppress deformation during vapor deposition. However, if the difference in the shrinkage ratio of the vacuum insulation material after the heat-drying step shrinks is large, evaporation damage may occur. In this case, it is also impossible to maintain the vacuum state inside the vacuum heat insulating material for a long period of time, and it is not possible to suppress an increase in thermal conductivity.

The present invention aims to solve the above-mentioned problems, and an object thereof is to provide a vacuum heat insulating material and a heat insulating box. After the drying step by heating during manufacture, the gas barrier properties of the outer material are not reduced, and the heat insulating performance can be maintained for a long time.
Problem solving

The vacuum insulation material of the present invention is a vacuum insulation material obtained by decompressing and sealing the inside of the outer casing, and includes: a core material for maintaining a vacuum space; an adsorbent for adsorbing moisture; coating the core material and the adsorption The outer covering material is composed of a surface protective layer, a gas barrier layer containing at least two kinds of gas barrier films, and a heat-sealing layer. When the at least two kinds of gas barrier films are heated at 100 ° C, For 2 hours or more, the difference in shrinkage of the at least two types of gas barrier films is within 2%.

The heat insulation box of the present invention is provided with the vacuum insulation material described above.
Invention effect

According to the vacuum insulation material and the heat insulation box according to the present invention, when the at least two types of gas barrier films are heated at 100 ° C. for more than 2 hours, the difference between the shrinkage ratios of the at least two types of gas barrier films is within 2%. . Thereby, after the drying step by heating at the time of manufacturing, the difference in the amount of shrinkage in at least two types of gas barrier films does not have an excessively large difference, and evaporation damage and the like can be suppressed. Therefore, even after the drying step by heating during manufacturing, the gas barrier properties of the outer cover material are not reduced, and the heat insulation performance can be maintained for a long period of time.

Hereinafter, embodiments of the present invention will be described based on the drawings. Moreover, in each figure, the same symbol is assigned to the same or equivalent, and this is the same throughout the specification. In the drawing of the cross-sectional view, hatching is appropriately omitted based on visibility. The forms of the constituent elements shown throughout the specification are merely examples, and are not limited to these descriptions.

Embodiment 1.
＜ Construction of vacuum insulation material ＞
FIG. 1 is a sectional view showing a schematic configuration of a vacuum heat insulating material 1 according to the first embodiment of the present invention. In addition, in the following drawings including FIG. 1, the dimensional relationship, shape, etc. of each constituent member may be different from the actual thing. The specific dimensions and the like of each constituent material should be determined after referring to the following description.

As shown in FIG. 1, the vacuum heat insulating material 1 is a heat insulating material which realizes a low thermal conductivity by making the inside thereof a vacuum. The vacuum heat insulating material 1 has a substantially rectangular flat plate shape as a whole. The vacuum insulation material 1 includes a core material 2, an adsorbent 3, and an outer cover material 4.

The core material 2 maintains a vacuum space. The adsorbent 3 adsorbs at least moisture. The cover material 4 covers the core material 2 and the adsorbent 3.

The vacuum space in the interior sealed by the outer cover 4 is reduced in pressure from the opening, and the opening is fused by heat sealing or the like, so that the inside of the outer cover 4 is reduced in pressure and sealed.

<Configuration of Core Material 2>
The purpose of using the core material 2 is to maintain a vacuum space. A fiber assembly such as glass wool is generally used as the core material 2. In addition, the fiber assembly constituting the core material 2 may be a product that is heat-pressed, a product that is sealed with an inner packaging material, and a product that is bonded by a binder.

<Configuration of Adsorbent 3>
The adsorbent 3 adsorbs water vapor inside the vacuum heat insulating material 1 and suppresses an increase in the heat transfer rate by maintaining the degree of vacuum. As the adsorbent 3, calcium oxide was used. Calcium oxide is also abbreviated as CaO.

<Configuration of Outer Material 4>
The cover material 4 is composed of two laminated films having a multilayer structure of a surface protective layer 41, a gas barrier layer 42, and a heat-welded layer 43. In the outer cover material 4, the heat-welded layers 43 are fused to each other, are joined at the sealing portion 43 a, and cover the core material 2 and the adsorbent 3. At this time, the outer material 4 is:
The sealing portion 43a is fused while being decompressed to a degree of vacuum of about 1 to 3 Pa (Pa), and the inside thereof is decompressed and sealed.

In addition, the outer cover material 4 may be such that each heat-welded layer 43 has a different thickness. As the outer cover material 4 covering the core material 2 and the adsorbent 3, two outer cover materials 4 may be used, and one outer cover material 4 may be folded. As long as the core material 2 and the adsorbent 3 can be sealed under reduced pressure, the number of the outer material 4 is not limited.

<Configuration of Surface Protection Layer 41>
The film thickness of the surface protective layer 41 is 25 μm or the like. The material of the surface protective layer 41 may be a plastic resin having a melting point of 150 ° C. or higher and good scratch resistance. For example, stretched polyamide such as stretched nylon, polyethylene terephthalate, stretched polypropylene, or the like can be used. Stretched nylon is also referred to as ONY. Polyethylene terephthalate is also simply referred to as PET. Elongated polypropylene is also referred to as OPP.

<Configuration of Gas Barrier Layer 42>
The gas barrier layer 42 is made of a thermoplastic resin having good barrier properties against water vapor and air. For example, two gas barrier films having a thickness of 12 μm are laminated to form the gas barrier layer 42. The gas barrier layer 42 may be a gas barrier film including at least two types. That is, the gas barrier layer 42 may not only be formed by laminating two gas barrier films of two types, but also may be formed by laminating two or more gas barrier films of three or more types.

The material of the gas barrier layer 42 can be: inorganic vapor-deposited polyethylene terephthalate, inorganic vapor-deposited ethylene / vinyl alcohol, or the above-mentioned difference in shrinkage when heated at 100 ° C. for 2 hours is 2 Combination of two kinds of gas barrier films within%. In addition, the gas barrier layer 42 is such that the surfaces of the two gas barrier films on which the inorganic vapor deposition has been applied are relatively adhered to each other. In addition, when the gas barrier layer 42 is composed of three or more gas barrier films, inorganic vapor deposition may be performed on the surface of the gas barrier film sandwiched between the surfaces so that the surfaces on which the inorganic vapor deposition has been applied are relatively mutually paste. The inorganic material vapor-deposited on the thermoplastic resin is not limited to aluminum, and may be aluminum oxide, silicon dioxide, or a combination thereof. Ethylene / vinyl alcohol is also simply referred to as EVOH.

The shrinkage was calculated from the dimensional change after cutting each gas barrier film to a side length of 250 mm square and drying it at 100 ° C for 2 hours. In addition, the shrinkage rate is a fixed value even if the size changes in each gas barrier film.

<Configuration of Thermal Welding Layer 43>
The film thickness of the heat-welded layer 43 is 30 μm or the like. As the material of the heat-welding layer 43, a thermoplastic resin or the like having a melting point of 150 ° C. or less is selected. However, the material of the thermal fusion bonding layer 43 is not particularly specified. For example, a low-density polyethylene or a lock-like low-density polyethylene is used as the heat-welded layer 43. The heat-welded layer 43 is more preferably a high-density polyethylene or an unstretched polypropylene having a high elastic modulus and excellent water vapor blocking properties. Low density polyethylene is also simply referred to as LDPE. The straight-locking low-density polyethylene is also referred to as LLDPE for short. High density polyethylene is also referred to as HDPE. Unstretched polypropylene is also simply referred to as CPP. In addition, in the following description, the abbreviation mentioned above is enclosed in parentheses.

The laminated film described above is the vacuum insulation material 1 before vacuum suction. At least three sides are heat-sealed, and even if it is heated and dried at 100 ° C for more than 2 hours, the gas barrier films 42 are formed. The difference in shrinkage is preferably within 2%.

<Manufacturing steps of vacuum insulation material 1>
In the manufacturing process of the vacuum heat insulating material 1, first, the core material 2 is covered with the outer cover material 4 which consists of the multilayer structure of the surface protection layer 41, the gas barrier layer 42, and the heat-welding layer 43. Then, the core material 2 and the outer cover material 4 are dried. The core material 2 covered with the cover material 4 is subjected to a heat treatment at 100 ° C. for 2 hours or more to remove water from the core material 2 and the cover material 4. At this time, the difference in shrinkage after heat treatment in at least two or more gas barrier films forming the gas barrier layer 42 is within 2%. Thereby, the occurrence of cracks in the inorganic vapor deposition surface can be suppressed, and the heat insulation performance can be maintained for a long time without reducing the gas barrier properties.

Next, the adsorbent 3 is arranged between the core material 2 and the outer cover material 4. Thereafter, the inside of the outer cover 4 is decompressed to a degree of vacuum of about 1 to 3 Pa, and the openings of the outer cover 4 are fused by heat sealing or the like in this reduced pressure state to decompress the inside of the outer cover 4. seal.

The vacuum heat insulating material 1 obtained through the above steps is that among the at least two types of gas barrier films on which the inorganic vapor-deposited surfaces constituting the gas barrier layer 42 are relatively adhered to each other, the difference in shrinkage after heat treatment is within 2%. Thereby, it is possible to suppress the occurrence of cracks in the inorganic vapor deposition layer, and to maintain a state in which the degree of vacuum in the vacuum insulation material 1 is maintained for a long period of time, and the amount of increase in thermal conductivity is suppressed.

<Comparison of Examples and Comparative Examples>
The vacuum heat insulating material 1 according to the first embodiment was produced and compared with the comparative example for the examples. The comparison results are described below.

Example 1.
In Example 1, aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) and silicon dioxide vapor-deposited stretched nylon (ONY) were used as two gas-barrier layers 42 of the gas-barrier layer 42 constituting the outer cover 4 of the vacuum insulation material 1. membrane. Then, the relationship between the water vapor transmission rate of the outer cover material 4 caused by the difference between the shrinkage ratios of the silicon dioxide vapor-deposited stretched nylon (ONY) and aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) and the vacuum insulation material 1 The relationship between the increase in thermal conductivity.

As the surface protective layer 41 of the outer cover 4, a stretched nylon (ONY) having a film thickness of 25 μm was used. As the gas barrier layer 42, a silicon dioxide vapor-deposited stretched nylon (ONY) having a film thickness of 12 μm and an aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) having a film thickness of 12 μm were used. As the heat-welded layer 43, a non-stretched polypropylene (CPP) having a film thickness of 30 μm was used. The core material 2 of the vacuum insulation material 1 is made of glass wool.

A laminated film formed by laminating the surface protective layer 41, the gas barrier layer 42, and the heat-welded layer 43 of the above specifications as the outer cover material 4 and covering the core material 2 with the outer cover material 4 to produce a vacuum insulation material 1.

Regarding the water vapor transmission rate, the water vapor transmission rate under the condition of 40 ° C and 90% RH, which is a laminated film of the packaging material 4 which has been dried at 100 ° C for 2 hours or more, was investigated. In addition, GTR-1000XAMD manufactured by GTR TEC was used for the measurement.

In addition, regarding the amount of increase in thermal conductivity, the thermal conductivity of the vacuum insulation material 1 immediately after manufacture and the thermal conductivity of the vacuum insulation material 1 after it was stored for 30 days in an environment with a temperature of 30 ° C and a relative humidity of 60% were investigated. Calculate the difference as the increase.

In the sample of Example 1, the difference between the shrinkage ratio of aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) and aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) having a thickness of 12 μm on the gas barrier layer 42 was less than 2%. The vacuum insulation material 1 of 12 μm silicon dioxide vapor-deposited stretched nylon (ONY).

The sample used in Comparative Example 1 was a gas barrier layer 42 of the outer cover material 4 of the vacuum insulation material 1 with a difference of 2.2% and 2.3% from the shrinkage ratio of aluminum vapor-deposited ethylene / vinyl alcohol (EVOH). Silicon dioxide vapor-deposited stretched nylon (ONY) with a thickness of 12 μm. Other configurations, conditions, and the like are the same as those of the sample of Example 1.

FIG. 2 is a graph showing the results of comparing the increase amounts of the thermal conductivity of the vacuum insulation material 1 in the samples of Example 1 and Comparative Example 1 of Embodiment 1 of the present invention. FIG. 3 is a graph showing the relationship between the difference between the water vapor transmission rate and the shrinkage rate of the outer cover material in Example 1 and Comparative Example 1 in Embodiment 1 of the present invention.

As shown in FIG. 2 and FIG. 3, the shrinkage ratio of each gas barrier film after heating and drying at 100 ° C. for 2 hours shows the results described below. The aluminum-evaporated ethylene / vinyl alcohol film had a shrinkage of 2.6%. The silicon dioxide vapor-deposited stretched nylon film of the sample of Example 1 had shrinkage ratios of 1.2% and 0.8%. The silica-evaporated stretched nylon film of the sample of Comparative Example 1 had shrinkage ratios of 0.4% and 0.2%.

In addition, the sample of Example 1 had a water vapor permeability of a laminated film having a silicon dioxide vapor-deposited stretched nylon film and an aluminum vapor-deposited ethylene / vinyl alcohol film on the gas barrier layer 42 of 2.4 mg / (m ² ‧day) And 2.5 mg / (m ² ‧day). The sample of Comparative Example 1 had a laminated film having a silicon dioxide vapor-deposited stretched nylon film and an aluminum-evaporated ethylene / vinyl alcohol film on the gas barrier layer 42. The water vapor permeability was 7.7 mg / (m ² ‧day) and 9.6 mg / (m ² ‧day).

From the above results, it can be seen that when the difference between the shrinkage ratios of the silicon dioxide-evaporated stretched nylon film and the aluminum-evaporated ethylene / vinyl alcohol film exceeds 2%, the water vapor permeability tends to increase sharply. That is, as shown in FIG. 3, a graph with the difference in shrinkage ratio as the horizontal axis and water vapor permeability as the vertical axis is used. In FIG. 3, the water vapor transmission rate of 2.4 mg / (m ² ‧day) of the sample in Example 1 of FIG. 2 is plotted as a. The water vapor transmission rate of 2.5 mg / (m ² ‧day) of the sample in Example 1 is plotted as b. The water vapor transmission rate of 7.7 mg / (m ² ‧day) of the sample in Comparative Example 1 is plotted as c. The water vapor transmission rate of 9.6 mg / (m ² ‧day) of the sample in Comparative Example 1 is plotted as d. The points a to d are connected to compare the difference with the shrinkage rate. As a result, if the difference between the shrinkage ratios is 2%, the inflection point is estimated, and from the inflection point, the water vapor permeability is maintained at a gentle and small state where the difference between the shrinkage ratios is within 2%. under. On the other hand, when the difference in the shrinkage ratio from the vicinity of the inflection point where the difference in the shrinkage ratio is 2% exceeds 2%, the water vapor transmission rate rapidly increases. Therefore, it can be seen that the turning point where the difference in shrinkage is 2% is of critical significance.

As shown in FIG. 2, the thermal conductivity of the vacuum insulation material 1 of Example 1 and Comparative Example 1 immediately after fabrication was 1.8 mW / (m · K). After being stored for 30 days in an environment with a temperature of 30 ° C and a relative humidity of 60%, the increase in the thermal conductivity of the vacuum insulation material 1 of Example 1 was 0.6 mW / (m‧K) and 0.7 mW / (m‧K). . The thermal conductivity of the vacuum insulation material 1 of Comparative Example 1 was 1.1 mW / (m‧K) and 1.2 mW / (m‧K) after being stored for 30 days in an environment of a temperature of 30 ° C and a relative humidity of 60%.

From the above results, it can be seen that when the difference between the shrinkage ratios of the silicon dioxide-evaporated stretched nylon film and the aluminum-evaporated ethylene / vinyl alcohol film exceeds 2%, the amount of increase in thermal conductivity tends to increase sharply.

As described above, taking Example 1 as an example, silicon dioxide vapor-deposited stretched nylon (with a difference of less than 2% from the shrinkage of aluminum and ethylene-vinyl alcohol (EVOH) after heating and drying at 100 ° C for 2 hours was used. ONY), good results can be obtained. That is, after the heating and drying step, high gas barrier properties can be maintained, and a low increase in heat transfer rate can be maintained for a long time.

Example 2.
In Example 2, aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) and silicon dioxide vapor-deposited polyparaphenylene diene were used as two gas-barrier films constituting the gas-barrier layer 42 of the outer cover 4 of the vacuum insulation material 1. Ethylene formate (PET). Furthermore, for Example 2, a comparison was made between the water vapor transmission rate of the packaging material 4 other than the sample of Example 1 and the increase in the thermal conductivity of the vacuum insulation material 1.

A 25 μm-thick stretched nylon (ONY) was used as the surface protective layer 41 of the outer cover 4. 12 μm thick silicon dioxide vapor-deposited polyethylene terephthalate (PET) and 12 μm thick aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) were used as the gas barrier. Layer 42. As the heat-welded layer 43, a non-stretched polypropylene (CPP) having a film thickness of 30 μm was used. The core material 2 of the vacuum heat insulating material 1 is made of glass wool.

A laminated film formed by laminating the surface protective layer 41, the gas barrier layer 42, and the heat-welded layer 43 of the above specifications as the outer cover material 4 and covering the core material 2 with the outer cover material 4 to produce a vacuum insulation material 1.

Regarding the amount of increase in the thermal conductivity, the thermal conductivity of the vacuum insulation material 1 immediately after it was manufactured and the thermal conductivity of the vacuum insulation material 1 after being stored for 30 days in an environment with a temperature of 30 ° C and a relative humidity of 60% were calculated and calculated. The difference is taken as the increase.

In the sample of Example 2, the difference between the shrinkage ratio of aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) and aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) having a thickness of 12 μm on the gas barrier layer 42 was less than 2%. A vacuum insulation material 1 of 12 μm thick silicon dioxide vapor-deposited polyethylene terephthalate (PET).

FIG. 4 is a graph showing a result of comparing the amount of increase in the thermal conductivity of the vacuum heat insulating material in the sample of Example 2 of Embodiment 1 of the present invention.

As shown in FIG. 4, the shrinkage ratio of each gas barrier film after being heated and dried at 100 ° C. for 2 hours showed the results described below. The aluminum-evaporated ethylene / vinyl alcohol film had a shrinkage of 2.6%. The shrinkage ratio of the silicon dioxide vapor-deposited polyethylene terephthalate film of the sample of Example 2 was 1.4%. The sample of Example 2 had a laminated film of silicon dioxide vapor-deposited polyethylene terephthalate film and aluminum vapor-deposited ethylene / vinyl alcohol film on the gas barrier layer 42 of 2.2 mg / (m ² ‧day). The thermal conductivity of the vacuum insulation material 1 of Example 2 immediately after fabrication was 1.8 mW / (m · K). After being stored for 30 days in an environment with a temperature of 30 ° C. and a relative humidity of 60%, the increase in the thermal conductivity of the vacuum insulation material 1 of Example 2 was 0.5 mW / (m · K).

Compared with Example 1 of FIG. 2, in Example 2, a polyethylene terephthalate film having a water vapor transmission rate lower than that of stretched nylon was used for the substrate. As a result, in Example 2, the gas barrier property higher than that in Example 1 can be maintained, and the amount of increase in the heat transfer rate can be maintained for a long time.

Example 3.
In Example 3, aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) and alumina vapor-deposited polyethylene terephthalate were used as two gas-barrier films constituting the gas-barrier layer 42 of the outer cover 4 of the vacuum insulation material 1. Diester (PET). In Example 3, a comparison was made between the water vapor permeability of the packaging material 4 other than the sample of Example 2 and the amount of increase in the thermal conductivity of the vacuum insulation material 1.

A 25 μm-thick stretched nylon (ONY) was used as the surface protective layer 41 of the outer cover 4. 12 μm alumina vapor-deposited polyethylene terephthalate (PET) and 12 μm aluminum-evaporated ethylene / vinyl alcohol (EVOH) were used as the gas barrier layer. 42. As the heat-welded layer 43, a non-stretched polypropylene (CPP) having a film thickness of 30 μm was used. The vacuum insulation material 1 is composed of glass wool and its core material 2.

A laminated film formed by laminating the surface protection layer 41, the gas barrier layer 42, and the heat-welded layer 43 of the above specifications as the outer cover material 4 and covering the core material 2 with the outer cover material 4 to produce a vacuum insulation material 1.

Regarding the increase in the thermal conductivity, the thermal conductivity of the vacuum insulation material 1 immediately after the manufacturing number and the thermal conductivity of the vacuum insulation material 1 after being stored for 30 days in an environment with a temperature of 30 ° C and a relative humidity of 60% were calculated and calculated. The difference is taken as the increase.

In the sample of Example 3, an aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) having a film thickness of 12 μm on the gas barrier layer 42 was used, and the difference between the shrinkage ratio and the aluminum vapor-deposited ethylene / vinyl alcohol (EVOH) was less than 2%. A vacuum insulation material 1 having a thickness of 12 μm and alumina vapor-deposited polyethylene terephthalate (PET).

FIG. 5 is a graph showing a result of comparing the increase amount of the thermal conductivity of the vacuum heat insulating material in the sample of Example 3 of Embodiment 1 of the present invention.

As shown in FIG. 5, the shrinkage rate of each gas barrier film after heating and drying at 100 ° C. for 2 hours exhibits the results described below. The aluminum-evaporated ethylene / vinyl alcohol film had a shrinkage of 2.6%. The alumina vapor-deposited polyethylene terephthalate film of the sample of Example 3 had a shrinkage of 1.2%. The sample of Example 3 has a vapor-permeability of 1.9 mg / (m ^{2) of} a laminated film having an aluminum oxide vapor-deposited polyethylene terephthalate film and an aluminum vapor-deposited ethylene / vinyl alcohol film on the gas barrier layer 42. ‧Day). The thermal conductivity of the vacuum insulation material 1 of Example 3 immediately after fabrication was 1.8 mW / (m · K). The amount of increase in the thermal conductivity of the vacuum insulation material 1 of Example 3 after being stored for 30 days in an environment of an air temperature of 30 ° C. and a relative humidity of 60% was 0.3 mW / (m · K).

Compared with Example 2 of FIG. 4, in Example 3, alumina was vapor-deposited using a vapor transmission rate lower than that of silicon dioxide. As a result, in Example 3, the gas barrier property higher than that in Example 2 can be maintained, and the increase amount of the heat transfer rate can be kept low for a long period of time.

<Effect of Embodiment 1>
According to the first embodiment, the vacuum heat insulating material 1 includes a core material 2 that holds a vacuum space. The vacuum heat insulating material 1 is provided with the adsorbent 3 which adsorbs moisture. The vacuum heat insulating material 1 includes an outer covering material 4 covering a core material 2 and an adsorbent 3. The vacuum heat insulating material 1 is configured to reduce the pressure inside the outer covering material 4 and seal it. The cover material 4 is composed of a surface protective layer 41, a gas barrier layer 42 including at least two types of gas barrier films, and a thermal fusion bonding layer 43. The at least two types of gas barrier films are such that, when heated at 100 ° C. for 2 hours or more, the difference in shrinkage of the at least two types of gas barrier films is within 2%.

According to this configuration, after the drying step by heating at the time of manufacturing, there is no significant difference in the difference in the amount of shrinkage in at least two types of gas barrier films. That is, the inorganic vapor deposition in the gas barrier layer 42 is less likely to undergo vapor deposition damage or the like after the drying step by heating during manufacturing, and the gas barrier properties are not reduced. Therefore, the degree of vacuum inside the vacuum heat insulating material 1 can be maintained, and an increase in the heat transfer rate can be suppressed. Therefore, even after the drying step by heating during manufacturing, the gas barrier properties of the outer cover 4 are not reduced, and the heat insulation performance can be maintained for a long period of time.

According to the first embodiment, the gas barrier layer 42 is a surface on which at least two types of gas barrier films are subjected to inorganic vapor deposition and are relatively adhered to each other.

According to this configuration, after the drying step by heating during manufacturing, the inorganic vapor deposition which is relatively adhered to the surface of the gas barrier layer 42 is unlikely to cause vapor deposition damage, and the gas barrier properties are not reduced. Therefore, it is possible to maintain the degree of vacuum inside the vacuum heat insulating material 1 and suppress an increase in the heat transfer rate.

According to Embodiment 1, the gas barrier layer 42 is composed of ethylene / vinyl alcohol (EVOH) to which inorganic vapor deposition is applied and stretched nylon (ONY) to which inorganic vapor deposition is applied.

According to this configuration, the difference in shrinkage ratio between the two types of gas barrier films is reduced after the drying step by heating during manufacturing. Thereby, the inorganic vapor deposition on the gas barrier layer 42 is less likely to be damaged by vapor deposition, and the gas barrier properties are not reduced. Therefore, it is possible to maintain the degree of vacuum inside the vacuum heat insulating material 1 and suppress an increase in the heat transfer rate.

According to Embodiment 1, the gas barrier layer 42 is composed of ethylene / vinyl alcohol (EVOH) subjected to inorganic vapor deposition and polyethylene terephthalate (PET) subjected to inorganic vapor deposition.

According to this structure, after the drying step by heating at the time of manufacture, the difference in the shrinkage ratio between the two types of gas barrier films becomes small. Thereby, the inorganic vapor deposition of the gas barrier layer 42 is less prone to vapor deposition damage, and the gas barrier properties are not reduced. Therefore, it is possible to maintain the degree of vacuum inside the vacuum heat insulating material 1 and suppress an increase in the heat transfer rate.

According to Embodiment 1, the material to be inorganic-deposited is aluminum, alumina, silicon dioxide, or a combination thereof.

According to this configuration, after the drying step by heating at the time of production, evaporation damage is less likely to occur in inorganic deposition.

Embodiment 2.
FIG. 6 is a sectional view showing a schematic configuration of a heat insulation box 100 according to Embodiment 2 of the present invention. The heat insulation box 100 is, for example, a refrigerator or a freezer, in which long-term heat insulation performance is sought.

As shown in FIG. 6, 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 heat insulating material 1 described in Embodiment 1 is arranged. The vacuum heat insulating material 1 performs heat insulation between the inner case 110 and the outer case 120. The position where the vacuum heat insulating material 1 is arranged is, for example, a position in close contact with the outer wall surface of the inner box 110. The vacuum heat insulating material 1 may be disposed at a position where heat can be insulated between the inner box 110 and the outer box 120.

As described above, the heat insulation box 100 is provided with the vacuum heat insulation material 1 having a low thermal conductivity. Thereby, the thermal conductivity between the inner case 110 and the outer case 120 is maintained in a low state. Therefore, the high heat insulation performance of the heat insulation box 100 can be maintained for a long period of time. Furthermore, reduction in power consumption is achieved in refrigerators, freezers, and the like provided with the heat insulation box 100.

Compared with the polyurethane foam insulation material 130 and the like, the vacuum insulation material 1 has higher heat insulation performance. Therefore, the heat insulation box 100 can obtain higher heat insulation performance than the heat insulation box using only the polyurethane foam heat insulation material 130. In addition, the space between the inner box 110 and the outer box 120 may be filled with a urethane foam heat insulating material 130 in a portion other than the place where the vacuum heat insulating material 1 is disposed.

In the above description, the vacuum heat insulating material 1 of the heat insulating box 100 is in close contact with the outer wall surface of the inner box 110. However, the vacuum heat insulating material 1 may be in close contact with the inner wall surface of the outer box 120. The vacuum insulation material 1 may be disposed in a space between the inner box 110 and the outer box 120 by using a gasket or the like, and is not in close contact with either the inner box 110 or the outer box 120.

It should be noted that in the above description, illustrations and descriptions of portions that are the same as the heat insulation boxes used in general refrigerators and the like are omitted.

<Effect of Embodiment 2>
According to the second embodiment, the heat insulation box 100 includes the above-mentioned vacuum heat insulation material 1.

According to this configuration, in the heat insulation box 100 provided with the vacuum insulation material 1 described above, even in the vacuum insulation material 1, even after the drying step by heating during manufacture, the gas barrier properties of the outer cover material 4 are not improved. It will decrease and maintain its heat insulation performance for a long time.

＜ Others ＞
In addition, the vacuum insulation material 1 of the present invention is not limited to the above-mentioned embodiment and can be variously modified, and the above-mentioned embodiment or embodiment may be implemented in combination with each other.

For example, in the above-mentioned example, the drying system of the core material 2 and the outer cover material 4 in the manufacturing step is heat-treated at 100 ° C. for 2 hours. However, the temperature and time of the heat treatment are not limited to this, as long as it is a temperature and time capable of removing moisture from the core material 2 and the outer cover material 4.

The core material 2 and the outer cover material 4 are dried in a state where the core material 2 is covered with the outer cover material 4. However, after drying the core material 2 and the outer cover material 4 separately, the core material 2 may be covered with the outer cover material 4.

In the manufacturing process of the vacuum insulation material 1 of the first embodiment, the core material 2 and the outer cover material 4 are dried, and then the adsorbent 3 is arranged between the core material 2 and the outer cover material 4. However, the adsorbent 3 may be arranged before the core material 2 and the outer cover material 4 are dried.

In addition, in the above-mentioned second embodiment, the configuration in which the vacuum heat insulation material 1 is used in the heat insulation box 100 of a refrigerator having a cold and heat source is taken as an example. However, the present invention is not limited to this. The vacuum heat insulation material 1 can also be used in a heat insulation box of a heat insulation storehouse with a warm heat source, or a heat insulation box (ie, a cold insulation box) without a cool heat source and a warm heat source. In addition, the vacuum heat insulating material 1 is not only used for the heat insulation box 100, but also can be used as a heat insulation member of hot and cold equipment, such as an air-conditioning apparatus, a vehicle air conditioner, and a water heater. In addition, the shape of the vacuum heat insulating material 1 can also be used for a heat insulation bag, a heat insulation container, etc. which have an outer bag and an inner bag which can be deformed freely instead of a predetermined shape.

1‧‧‧Vacuum insulation material

2‧‧‧ core material

3‧‧‧ adsorbent

4‧‧‧ Outsourcing

41‧‧‧surface protection layer

42‧‧‧Gas barrier

43‧‧‧Heat Welding Layer

43a‧‧‧Seal Section

100‧‧‧ Insulation Box

110‧‧‧Inner box

120‧‧‧ Outer Box

130‧‧‧Polyurethane foam insulation material

[FIG. 1] A cross-sectional view showing a schematic configuration of a vacuum heat insulating material according to Embodiment 1 of the present invention.

[Fig. 2] A graph showing the results of comparing the amount of increase in the thermal conductivity of the vacuum insulation material in the samples of Example 1 and Comparative Example 1 of Embodiment 1 of the present invention.

FIG. 3 is a graph showing the relationship between the difference in water vapor transmission rate and shrinkage of the outer cover material in Example 1 and Comparative Example 1 in Embodiment 1 of the present invention.

FIG. 4 is a graph showing a result of comparing the increase in the thermal conductivity of the vacuum insulation material in the sample of Example 2 of Embodiment 1 of the present invention.

FIG. 5 is a graph showing a result of comparing the increase amount of the thermal conductivity of the vacuum heat insulating material in the sample of Example 3 of Embodiment 1 of the present invention.

6 A cross-sectional view showing a schematic configuration of a heat insulation box according to a second embodiment of the present invention.

Claims (6)

A vacuum insulation material includes: Core material to maintain vacuum space; Adsorbent for adsorbing moisture; An outer covering material covering the core material and the adsorbent; The vacuum insulation material is a vacuum insulation material obtained by decompressing and sealing the inside of the outer casing, The outer cover material is composed of a surface protective layer, a gas barrier layer containing at least two types of gas barrier films, and a heat-welded layer. When the at least two types of gas barrier films are heated at 100 ° C. for 2 hours or more, the difference in shrinkage of the at least two types of gas barrier films is within 2%. According to the vacuum heat insulation material described in the first item of the patent application scope, the gas barrier layer makes the surfaces of the at least two types of gas barrier films on which the inorganic vapor deposition has been applied relatively adhere to each other. According to the vacuum insulation material described in item 1 or 2 of the patent application scope, the gas barrier layer is composed of inorganic vapor-deposited ethylene / vinyl alcohol (EVOH) and inorganic vapor-deposited stretch nylon ( ONY). According to the vacuum insulation material described in the first or second scope of the patent application, the gas barrier layer is composed of inorganic vapor-deposited ethylene / vinyl alcohol (EVOH) and inorganic vapor-deposited polyparaphenylene. Made of ethylene formate (PET). According to the vacuum heat insulation material described in the second item of the patent application scope, the inorganic material to be inorganic-deposited is aluminum, aluminum oxide, silicon dioxide, or a combination thereof. A heat insulation box provided with the vacuum heat insulation material as described in the 1st or 2nd patent application range.