JP7087462B2 - Laminates and vacuum heat insulating materials - Google Patents

Description

The present invention relates to a laminated body, and this laminated body is suitable as, for example, an exterior film of a vacuum heat insulating material.

The vacuum heat insulating material is applied to, for example, a refrigerator, a low temperature container, an outer wall material of a house, or the like to block heat conduction inside and outside the vacuum heat insulating material. As the vacuum heat insulating material having excellent heat insulating performance, the core material 2 is sealed in the laminated body 1 which is an exterior film, the inside is evacuated, and the laminated body 1 which is an exterior film is heat-sealed. The vacuum heat insulating material A is known (see FIG. 2).

The laminated body 1 which is the exterior film needs to have excellent gas barrier properties in order to prevent the intrusion of gas from the outside and keep the inside in a vacuum state for a long period of time. Therefore, there is known a laminated body 1 which is an exterior film having a high gas barrier property by using two gas barrier layers (Patent Document 1). The two gas barrier layers are, for example, one of the gas barrier layers is a vapor-filmed film on which an inorganic substance such as alumina is vapor-deposited, and the other gas barrier layer is a thin-film film on which a metal such as aluminum is vapor-deposited.

The laminated body 1 which is the exterior film is excellent in gas barrier property and can maintain gas barrier property even if the heat seal portion is bent.

However, for example, when applied to a refrigerator or the like, it is necessary to form a groove in the vacuum heat insulating material, and since the vacuum heat insulating material is bent by this groove, the vacuum heat insulating material needs to be deformed along the groove. However, since the exterior film of the conventional vacuum heat insulating material is partially stretched by this bending, the gas barrier property may be lowered and the heat insulating performance of the vacuum heat insulating material may be lowered.

JP-A-2015-3427

Therefore, an object of the present invention is to provide a laminate that can be used as an exterior film whose gas barrier property does not deteriorate even when the vacuum heat insulating material is deformed.

That is, the invention according to claim 1 is a laminate in which a base film, a first gas barrier layer, a second gas barrier layer, and a sealant layer are laminated in this order.
The first gas barrier layer is a thin-film film having an inorganic or metal thin-film film.
The second gas barrier layer is an ethylene-vinyl alcohol copolymer film.
The layers are joined to each other via an acrylic pressure-sensitive adhesive layer .
The acrylic pressure-sensitive adhesive layer is a laminate characterized in that the acrylic pressure-sensitive adhesive main agent and a cross-linking agent for cross-linking the acrylic pressure-sensitive adhesive are cross-linked by reacting with each other .

Next, the invention according to claim 2 is a vacuum heat insulating material characterized in that the laminate according to claim 1 is used as an exterior film and the core material is sealed with the exterior film.

Since the laminate of the present invention has two gas barrier layers as in the prior art, it is excellent in gas barrier property, and moreover, the gas barrier property can be maintained even if the heat-sealed portion is bent.

By the way, acrylic adhesives have a low Young's modulus and are highly flexible. In the laminate of the present invention, each layer of the base film, the first gas barrier layer, the second gas barrier layer and the sealant layer is bonded via the acrylic pressure-sensitive adhesive layer, and the first gas barrier layer and the second are bonded. Since all of the gas barrier layers in the above are sandwiched between the acrylic pressure-sensitive adhesive layers, the acrylic pressure-sensitive adhesive acts as a cushioning material between each layer even when this laminate is stretched to prevent damage to the gas barrier layer. do. Even when the vacuum heat insulating material in which the core material is sealed using the laminate of the present invention as an exterior film is bent and deformed, the gas barrier layer is not damaged, the gas barrier property is maintained, and the heat insulating material of the vacuum heat insulating material is heat-insulated. It is possible to maintain the performance.

FIG. 1 is a cross-sectional explanatory view showing a specific example of the laminated body of the present invention. FIG. 2 relates to an example of the vacuum heat insulating material, FIG. 2A is a perspective explanatory view thereof, and FIG. 2B is a cross-sectional explanatory view thereof.

Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional explanatory view showing a specific example of the laminated body of the present invention. As can be seen from this figure, the laminated body 1 is formed by laminating the base film 11, the first gas barrier layer 12, the second gas barrier layer 13, and the sealant layer 14 in this order, and the layers 11 and 12 are formed. , 13 and 14 are bonded to each other via acrylic pressure-sensitive adhesive layers a1, a2 and a3. That is, the base material 11 and the first gas barrier layer 12 are bonded via the acrylic pressure-sensitive adhesive layer a1, and the first gas barrier layer 12 and the second gas barrier layer 13 have an acrylic pressure-sensitive adhesive layer a2. It is joined through. Further, the second gas barrier layer 13 and the sealant layer 14 are joined via an acrylic pressure-sensitive adhesive layer a3. As described above, both the first gas barrier layer and the second gas barrier layer are sandwiched between the acrylic pressure-sensitive adhesive layers.

Any resin film can be used as the base film 11. It may be a film having a single layer structure, or it may be a laminated film having a multilayer structure in which a plurality of resin films are laminated. Further, a non-stretched film, a uniaxially stretched film, or a biaxially stretched film may be used, and a uniaxially stretched film or a biaxially stretched film can be preferably used because of its excellent dimensional stability. The thickness thereof may be, for example, 3 to 200 μm.

Examples of the resin film that can be used for the base film 11 include a polyester-based resin film, a polyamide-based resin film, a polyolefin-based resin film, and a vinyl alcohol-based resin film. Examples of the polyester-based resin film include films such as polyethylene terephthalate, polyethylene naphthalate, polyethylene-2,6-naphthalate, and polybutylene terephthalate. Examples of the polyamide-based resin film include films such as nylon-6, nylon-66, and nylon-12. Further, as the polyolefin-based resin film, a film such as polyethylene or polypropylene can be exemplified. Examples of the vinyl alcohol-based resin film include films such as polyvinyl alcohol and an ethylene-vinyl alcohol copolymer.

Both the first gas barrier layer 12 and the second gas barrier layer 13 have a function of preventing gas from entering the inside of the vacuum heat insulating material. A metal foil such as an aluminum foil may be used, but the metal foil has a high thermal conductivity, and heat is transferred to the inside and outside of the vacuum heat insulating material through the metal foil, and as a result, the heat insulating performance may be deteriorated. Therefore, it is desirable that both the first gas barrier layer 12 and the second gas barrier layer 13 are made of a thin-film film having a thin-film film of an inorganic substance or a metal. A vapor-deposited film having an inorganic vapor-film-deposited film is desirable. It is also possible to use an ethylene-vinyl alcohol copolymer film as the first gas barrier layer 12 or the second gas barrier layer 13.

A vapor-deposited film having an inorganic-deposited film (inorganic-deposited film) is a film in which a thin film of an inorganic substance such as a metal oxide is formed on the vapor-filmed substrate. As the metal oxide, silicon oxide, aluminum oxide (alumina) and the like can be used. Such a thin film of metal oxide can be formed by, for example, a vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or a CVD method. As the vapor deposition base material of the inorganic vapor deposition film, a polyamide film, a polyethylene terephthalate film, a polyvinyl chloride film, an ethylene-vinyl alcohol copolymer film and the like can be used.

Further, a vapor-deposited film having a metal-deposited film (metal-deposited film) is a film in which a thin metal film is formed on the vapor-deposited base material. Aluminum can be used as this metal. Further, the thin film can be formed by the vapor phase growth method. As the vapor-deposited base material of the metal vapor-deposited film, a polyamide film, a polyethylene terephthalate film, a polyvinyl chloride film, an ethylene-vinyl alcohol copolymer film and the like can be used as in the vapor-deposited base material of the inorganic vapor-deposited film.

It is desirable to use a polyethylene terephthalate film as the vapor deposition base material of the inorganic vapor deposition film and to use an ethylene-vinyl alcohol copolymer film as the vapor deposition base material of the metal vapor deposition film. In this case, it is possible to improve the water resistance and the oxygen barrier property over a long period of time.

The first gas barrier layer 12 and the second gas barrier layer 13 may be made of the same type of thin-film vapor film, or may be made of different types of thin-film film. For example, both the first gas barrier layer 12 and the second gas barrier layer 13 can be made of an inorganic thin-film film, or both of them can be made of a metal-deposited film. It is also possible that the first gas barrier layer 12 is made of an inorganic thin-film film, while the second gas barrier layer 13 is made of a metal-deposited film. Of course, the first gas barrier layer 12 may be made of a metal-deposited film, and the second gas barrier layer 13 may be made of an inorganic-deposited film.

Next, various polyethylene-based resins, polypropylene, and the like can be used for the sealant layer 14. In particular, it is preferable to use a linear low-density polyethylene film having a density of 0.935 g / cm ³ or less. The thickness is preferably 30 to 80 μm. If the density is higher than 0.935 g / cm ³ , for example, the density is as high as 0.94 g / cm ³ , the bending resistance is deteriorated, which is not preferable.

As described above, each of these layers 11, 12, 13, 14 is an acrylic pressure-sensitive adhesive layer a1,
It is necessary to join via a2 and a3. As the acrylic pressure-sensitive adhesive layers a1, a2, and a3, an organic solvent type acrylic pressure-sensitive adhesive can be preferably used. Of these, a two-component acrylic pressure-sensitive adhesive containing an acrylic pressure-sensitive adhesive main agent and a cross-linking agent that crosslinks the acrylic pressure-sensitive adhesive is preferable. For example, Oliveine BPS5296 manufactured by Toyochem Co., Ltd. is used as the main agent of the acrylic pressure-sensitive adhesive, and Oliveine BXX4773 manufactured by Toyochem Co., Ltd. is used as a cross-linking agent. It is possible to form the acrylic pressure-sensitive adhesive layers a1, a2, and a3. The acrylic pressure-sensitive adhesive layers a1, a2, and a3 can be applied and formed by a dry lamination method.

By joining the layers 11, 12, 13, and 14 via the acrylic pressure-sensitive adhesive layers a1, a2, and a3, it is possible to manufacture the laminated body 1 in which the gas aria property does not deteriorate even when stretched.

As explained over and over again, this laminate 1 is suitable as an exterior film for a vacuum heat insulating material. That is, a bag is made using this laminated body 1, the core material 2 is stored from the opening thereof, and then the opening is heat-sealed and sealed while vacuum sucking the inside of the bag to insulate the vacuum. The material A can be manufactured. As the core material 2, inorganic fibers such as glass fibers and organic fibers such as polystyrene fibers can be used. Further, a board made by solidifying powder or a foamed resin can also be used. Further, powder such as foamed pearlite may be used.

The vacuum heat insulating material A thus obtained is excellent in heat insulating performance. Moreover, the exterior film maintains high gas barrier properties even when it is bent and partially stretched. For example, when the vacuum heat insulating material A is applied to a refrigerator or the like, it is necessary to make a groove in the vacuum heat insulating material, and since the vacuum heat insulating material is bent by this groove, the vacuum heat insulating material is deformed along this bending, and the exterior film is formed. It is stretched by about 6%. Since high gas barrier properties are maintained even when stretched by 6% in this way, it is possible to maintain excellent heat insulating performance.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

In addition, these Examples and Comparative Examples can be classified into two types. First, Examples 1 and Comparative Example 1 use an inorganic thin-film film on which an inorganic thin-film film is formed as the first gas barrier layer 12. Next, there are Example 2 and Comparative Example 2 in which a metal-deposited film on which a metal-deposited film is formed is used as the first gas barrier layer 12. Therefore, Example 1 and Comparative Example 1 using these inorganic vapor-film-deposited films and Example 2 and Comparative Example 2 using the metal-deposited film will be described separately.

The base film 11, the second gas barrier layer 13, and the sealant layer 14 used in Examples 1 and 2 and Comparative Examples 1 and 2 below are as follows, respectively, and these are Examples 1 and 2, respectively. And are common to Comparative Examples 1 and 2.

That is, first, as the base film 11, a polyamide film having a thickness of 25 μm (Bonil RX manufactured by Kohjin Film and Chemicals Co., Ltd.) was used.

As the second gas barrier layer 13, an ethylene-vinyl alcohol copolymer film (TM-XL manufactured by Kuraray Co., Ltd.) having a thickness of 15 μm was used.

The sealant layer 14 is a linear low-density polyethylene film (N601 manufactured by Aicello Corporation) having a thickness of 50 μm.

(Example 1)
In this example, as the first gas barrier layer 12, an inorganic thin-film film in which an inorganic thin-film film was formed on a biaxially stretched polyester film having a thickness of 12 μm was used.

Further, as an adhesive for joining the layers 1, 12, 13, and 14, a two-component acrylic pressure-sensitive adhesive containing an acrylic pressure-sensitive adhesive main agent and a cross-linking agent for cross-linking the acrylic pressure-sensitive adhesive was used. The main agent of the acrylic pressure-sensitive adhesive is Oliveine BPS5296 manufactured by Toyochem Co., Ltd., and the cross-linking agent is Oliveine BXX4773 manufactured by Toyochem Co., Ltd. These main agents and cross-linking agents were mixed and applied by a dry lamination method, and then the main agent and the cross-linking agent were reacted with each other to cross-link to form acrylic pressure-sensitive adhesive layers a1, a2, and a3.

(Comparative Example 1)
The first gas barrier layer 12 used in this example is the same as the inorganic vapor-filmed film of Example 1. In this example, as the adhesive for joining the layers 1, 12, 13, and 14, a two-component ester adhesive consisting of an ester-based laminate adhesive main agent and a cross-linking agent for cross-linking the ester-based laminate adhesive was used. The main agent of the ester-based laminated adhesive is TM570 manufactured by Toyo Morton Co., Ltd., and the cross-linking agent is CAT10L manufactured by Toyo Morton Co., Ltd. Then, as in Example 1, these main agents and the cross-linking agent are mixed, applied by the dry lamination method, and then the main agent and the cross-linking agent are reacted with each other to cross-link to form an ester-based pressure-sensitive adhesive layer. Then, each layer 1, 12, 13, 14 was joined.

(Evaluation of Example 1 and Comparative Example 1)
The laminates obtained in Example 1 and Comparative Example 1 were stretched by 6% and evaluated by measuring the oxygen permeability before and after the stretching. The oxygen permeability was measured by the MOCON method under the conditions of a temperature of 30 ° C. and a relative humidity of 70%. The results are shown in Table 1.

As can be seen from this result, when an acrylic pressure-sensitive adhesive is used as the adhesive for joining the layers 1, 12, 13, and 14 (Example 1), when other adhesives are used (Comparative Example 1). ), The deterioration of the gas barrier property when stretched is significantly less. Therefore, for example, it can be understood that the vacuum heat insulating material using this laminated body as an exterior film maintains excellent heat insulating performance even when it is bent and deformed.

(Example 2)
In this example, as the first gas barrier layer 12, a metal-deposited film obtained by forming a metal-aluminum-deposited film on a biaxially stretched polyester film having a thickness of 12 μm was used. The adhesive for joining the layers 1, 12, 13, and 14 is the same two-component acrylic pressure-sensitive adhesive as in Example 1.

(Comparative Example 2)
The first gas barrier layer 12 used in this example is the same as the metal-deposited film of Example 2. The adhesive is the same as the two-component ester adhesive of Comparative Example 1.

(Evaluation of Example 2 and Comparative Example 2)
The laminates obtained in Example 2 and Comparative Example 2 were evaluated by measuring the oxygen permeability before and after 6% stretching. As described above, the oxygen permeability was measured by the MOCON method under the conditions of a temperature of 30 ° C. and a relative humidity of 70%. The results are shown in Table 2.

From this result, even when a metal-deposited film is used as the first gas barrier layer 12,
When an acrylic pressure-sensitive adhesive is used as the adhesive for joining the layers 1, 12, 13, and 14 (Example 2), the stretch is compared with the case where other adhesives are used (Comparative Example 2). It can be seen that there is little deterioration in the gas barrier property when this is done.

In addition, in order to be able to understand by comparing Example 1 and Example 2, the person who used the inorganic vapor-deposited film as the first gas barrier layer 12 (Example 1) used the metal-deposited film (Example 1). Compared to 2), the deterioration of gas barrier property when stretched is significantly less.

1: Laminated body 11: Base film 12: First gas barrier layer 13: Second gas barrier layer 14: Sealant layer a1 to a3: Acrylic adhesive layer

Claims (2)

In a laminated body in which a base film, a first gas barrier layer, a second gas barrier layer, and a sealant layer are laminated in this order,
The first gas barrier layer is a thin-film film having an inorganic or metal thin-film film.
The second gas barrier layer is an ethylene-vinyl alcohol copolymer film.
The layers are joined to each other via an acrylic pressure-sensitive adhesive layer .
The acrylic pressure-sensitive adhesive layer is a laminate characterized in that the acrylic pressure-sensitive adhesive main agent and a cross-linking agent for cross-linking the acrylic pressure-sensitive adhesive layer are reacted with each other and cross-linked . A vacuum heat insulating material, wherein the laminate according to claim 1 is used as an exterior film, and the core material is sealed with the exterior film.

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