JPH11333966A - Highly moistureproof laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminate for packaging having transparency capable of discriminating content, keeping excellent high moistureproofness and capable of being burnt as waste. SOLUTION: In a laminate wherein a plurality of vapor deposition films 26, 27 obtained by providing vapor deposition films 31, 32 of metal oxide on base material films 21, 22 and a heat sealant layer 60 are laminated, at least one hygroscopic film 11 is inserted into the gap between the vapor deposition films.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly moisture-proof laminate formed from a plastic film, and more particularly, to a multilayer laminate comprising a plurality of films provided with metal oxide vapor-deposited films and having excellent transparency and high moisture-proof properties. Belong to the body.

[0002]

2. Description of the Related Art When the contents of a sealed package do not like a very small amount of moisture, for example, freeze-dried foods that discolor even due to the absorption of a very small amount of moisture, or backlights for displays of pharmaceuticals or audio equipment. A packaging material such as electroluminescence to be used is required to have a very high level of moisture-proof protection and transparency so that the contents can be identified. In order to simply provide the moisture resistance of the entire laminate, the solution can be substantially solved by including a metal foil such as aluminum having high moisture resistance as one element of the layer structure of the laminate. However, the use of the metal foil not only cannot identify the contents, but also has a lower temperature than the temperature at the time of filling and packaging the contents, or a very small amount of permeated moisture, such as when transporting by aircraft. When exposed under extremely low temperature conditions, there is a problem in that dew forms and the released water causes deterioration of the contents. To remove such dew moisture, silica gel, calcium oxide, calcium chloride, and aluminum chloride are also included as a method of enclosing a desiccant, but the desiccant causes contamination and deterioration of the contents. There was a problem.

[0003] As a transparent moisture-proof film, a film on which a metal oxide is deposited is used, but the required moisture-proof property cannot be satisfied, and the moisture-proof property cannot be maintained due to insufficient flexibility of the deposited film. There was a problem. Further, a laminate containing a film of a fluorine compound resin as a transparent high moisture-proof film has been used satisfactorily as a function. However, waste treatment, especially air pollution, which is different from chlorine compounds when incinerated may be a problem.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a laminate for packaging which has transparency so that the contents can be identified, maintains excellent high moisture proofness, and can easily treat waste by burning or the like. The task is to do so.

[0005]

In order to solve the above problems,
In the highly moisture-proof laminate of the present invention, at least two or more vapor-deposited films in which a metal oxide vapor-deposited film is formed on a base film are provided, and a heat sealant layer (hereinafter, referred to as an HS layer) is attached. A highly moisture-resistant laminate in which at least one moisture-absorbing film is inserted between layers of the vapor-deposited film. The moisture-absorbing film is a highly moisture-proof laminate formed of a polyamide.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A highly moisture-proof laminate of the present invention is shown in FIG.
As shown in FIG. 5, a plurality of vapor-deposited films 26 and 27 having metal oxide vapor-deposited films 31 and 32 provided on at least substrate films 21 and 22, respectively, and an HS layer 60 are laminated. 26 and 27, at least one moisture-absorbing film 11
The highly moisture-resistant laminate 100 is inserted and adhered through the second member 52. The moisture-absorbing film 11 is a highly moisture-proof laminate 100 made of polyamide.

[0007] The base film on which the deposited film of the present invention is provided comprises:
The film can be selected from films having excellent thermal stability, high dimensional accuracy, and no hindrance to the compounding process with other films when depositing a metal oxide. For example, a stretched or non-stretched film such as a polyester, polypropylene, or aromatic polyamide film, particularly a stretched polyethylene terephthalate film can be preferably used.

The metal oxide which forms a transparent vapor-deposited film by imparting moisture resistance to the substrate film includes aluminum oxide, tin oxide, indium oxide, and silicon oxide (hereinafter referred to as SiO _x ), and is preferably used. It is made of SiO _x . The formation of the deposited film can be selected from any of the conventionally applied vacuum deposition methods (physical vapor deposition, chemical vapor deposition) and sputtering.

The moisture-absorbing film to be inserted into the laminate of the present invention may be a stretched or unstretched film such as 6-nylon, 66-nylon, ethylene / vinyl acetate copolymer, polyvinyl alcohol or the like, or a base material such as cellophane or cellulose acetate. Some films have higher hygroscopicity than material film.

[0010] The highly moisture-proof laminate of the present invention is obtained by laminating a vapor-deposited film, a moisture-absorbing film and a vapor-deposited film,
The layers are stacked. For the lamination, a method such as dry lamination, which is a usual plastic film lamination method, or sandwich lamination using a hot-melt resin as an adhesive resin layer can be applied. Preferably, dry lamination (including lacquer lamination using a reaction-curable adhesive dissolved in a solvent and non-solami without solvent) that prevents thermal deterioration of the deposited film is used.

The material constituting the HS layer can be composed of a film mainly composed of polyethylene or polypropylene. For example, low-density polyethylene, linear polyethylene, medium-high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic ester copolymer, ionomer, etc., polypropylene, propylene and ethylene And other films. The lamination of the HS layer and the vapor-deposited film is performed by sandwich lamination using a hot-melt resin as an adhesive resin layer by providing a dry lamination or a primer layer of the vapor-deposited film and the resin obtained by forming the resin of the HS layer into a film. To form a high moisture-proof laminate.

The HS layer is formed by laminating a vapor-deposited film as described above. The HS layer is formed by laminating a heat-sealing resin film prepared in a separate process, and also by extruding a heat-sealing resin through a primer layer. Can also be formed. Further, by replacing the HS layer with an easily-openable one, the HS layer can be used as a highly moisture-proof lid material for a molded container or the like.

The following is presumed as the reason why the package heat-sealed and sealed with the HS layer using the laminate thus constructed has high moisture-proof property. That is, since the vapor-deposited film of the metal oxide formed on the laminate has excellent moisture-proof properties, the amount of water vapor that permeates the vapor-deposited film from the outside of the package is essentially small. Water vapor that permeates the vapor-deposited film is held in a state of being absorbed by the moisture-absorbing film and hardly permeates into the inside of the package. Even if the moisture retained in the moisture-absorbing film is in a supersaturated state, the vapor permeated between the moisture-absorbing film and the HS layer prevents the permeation of water vapor into the inside of the package. Therefore, it can be presumed that a laminate and a package having high moisture-proof properties as a whole and having higher moisture-proof properties than a laminate composed of two layers of a mere vapor-deposited film can be provided.

When the water vapor transmission rate of the vapor deposition film 27 located on the surface of the package shown in FIG. 1 was made larger than the water vapor transmission rate of the vapor deposition film 26 provided on the HS layer side, water was temporarily absorbed by the moisture absorbing film. It is conceivable that when the package is placed in a dry atmosphere, the water vaporizes outside the package and does not permeate into the package.

According to the present invention, as shown in FIG. 2, vapor-deposited films 26, 27
And 28 are composed of three layers and the HS layer 60, and the moisture-proof films 11 and 12 are provided between the vapor-deposited films via the adhesive layers 51, 52, 53 and 54. Can be configured.

An ultra-high moisture proof structure in which four layers of vapor-deposited films are used and a part corresponding to the vapor-deposited film 27 shown in FIG. 2 is laminated with the vapor-deposited films 27 and 28 via an adhesive layer 54 as shown in FIG. The highly moisture-proof laminate 102 comprising the two-layer vapor-deposited film 20 can also be constituted. In this configuration example, the vapor transmission rate of the vapor deposition film 29 located on the surface of the package is larger than that of the two-layer vapor deposition film 20 provided in the middle.
Then, the moisture transmitted through the vapor deposition film 29 on the surface of the laminate (package) is captured and held by the moisture absorbing film 12. Then, the passage of moisture that cannot be retained to the HS layer side is prevented by the two-layer deposited film 20. Further, the moisture absorbing film 11 provided between the two-layer deposited film 20 and the HS layer 60 side
To prevent moisture permeation on the HS layer side.

Hereinafter, the present invention will be described in more detail with reference to examples. The lamination of the examples and the comparative examples was all performed by ordinary dry lamination using a two-component curable urethane-based adhesive.

(Embodiment 1) As shown in FIG.
A polyester film (substrate film 22) of the 2μm coating a polyester isocyanate adhesive layer 53 on the side of the deposited film 32 of the deposited film 27 provided with a vapor-deposited film 32 of SiO _x, oriented nylon film having a thickness of 15 [mu] m ( And a moisture absorbing film 11). Further, the stretched nylon film 11 is coated with an adhesive layer 52 using the adhesive, and a 12 μm-thick polyester film (base film 21) is provided with a SiO _x deposited film 31 on the side of the deposited film 31 of the deposited film 26. And were laminated. Then, the polyester film 21 and a linear polyethylene (HS layer 60) having a thickness of 40 μm were similarly laminated to prepare a highly moisture-proof laminate 100 of Example 1.

(Embodiment 2) As shown in FIG.
An unstretched nylon film (moisture-absorbing film 11) having a thickness of 100 μm was laminated on the side of the vapor deposition film 32 of the vapor deposition film 27 in which a SiO _x vapor deposition film 32 was provided on a 2 μm polyester film (base film 22). Further, the unstretched nylon film 11 and the side of the vapor-deposited film 31 of the vapor-deposited film 26 in which a 12-μm-thick polyester film (base film 21) was provided with the vapor-deposited film 31 of SiO _x were laminated. And the polyester film 21 and the thickness of 40 μm
Was laminated with the linear polyethylene (HS layer 60) of Example 2 to prepare a highly moisture-proof laminate 100 of Example 2. In addition, the laminating method was performed according to Example 1.

(Comparative Example 1) Although not shown, the thickness 12
a deposition film vapor deposited film provided with vapor-deposited film of SiO _x on polyester film [mu] m, by laminating a vapor deposition film vapor deposited film provided with vapor-deposited film of SiO _x on a polyester film having a thickness of 12 [mu] m. Next, a stretched nylon film having a thickness of 15 μm and a linear polyethylene (HS layer) having a thickness of 40 μm are laminated, and a two-layer vapor-deposited film is laminated with the moisture-proof laminate of Comparative Example 1 provided with the stretched nylon film and the HS layer. Created body. In addition, the laminating method was performed according to Example 1.

[0021] (Comparative Example 2) Although not shown, a stretched nylon film was laminated with a vapor deposited film provided with vapor-deposited film of SiO _x 2 layers of polyester film having a thickness of 12 [mu] m. Further, the moisture-proof laminate of Comparative Example 2 in which a linear polyethylene (HS layer) having a thickness of 40 μm was laminated on the polyester film side of the above-mentioned vapor-deposited film, and the composition position of the stretched nylon layer was reversed from Comparative Example 1. It was created. In addition, the laminating method was performed according to Example 1.

(Comparative Example 3) Although not shown, the thickness 12
A deposited film of a deposited film in which a SiO _x deposited film was provided on a μm polyester film and a stretched nylon film having a thickness of 15 μm were laminated. Furthermore, a linear polyethylene (HS layer) having a thickness of 40 μm and the side of the stretched nylon film
Were laminated to produce a moisture-proof laminate of Comparative Example 3.

Each of the samples of the above Examples and Comparative Examples was subjected to JIS in a sheet state without processing and in a state including a cross part bent in quadruple with the HS layer in the middle.
Table 1 shows the results of the measured moisture permeability based on the K7129A method.

[0024]

[Table 1] └──────┴──────┴──────┘

[0025]

Since the present invention is configured as described above in detail, the present invention has the following effects. The moisture-absorbing film located inside the highly moisture-proof laminate adsorbs and retains a very small amount of moisture that has passed through the vapor-deposited film, and transmits moisture into the package with the vapor-deposited film provided on the HS layer side. Therefore, the laminate as a whole can have very high moisture-proof properties.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a basic configuration of a highly moisture-proof laminate.

FIG. 2 is a schematic cross-sectional view showing another configuration of the high moisture-proof laminate.

FIG. 3 is a schematic cross-sectional view showing another configuration of the high moisture-proof laminate.

[Explanation of symbols]

 11, 12 Moisture absorbing film 20 Two-layer deposited film 21, 22, 23, 24 Base film 26, 27, 28, 29 Deposited film 31, 32, 33, 34 Deposited film 51, 52, 53, 54, 55, 56 Adhesion Agent layer 60 HS layer 100, 101, 102 High moisture-proof laminate

Claims (2)

[Claims] 1. A laminate comprising a base film provided with at least two vapor-deposited films each having a metal oxide vapor-deposited film formed thereon, and further laminated with a heat sealant layer, wherein at least one layer is provided between the vapor-deposited films. A highly moisture-resistant laminate having the above moisture-absorbing film inserted therein. 2. The highly moisture-proof laminate according to claim 1, wherein the moisture-absorbing film is made of a polyamide film.