JPH06286043A - Laminate - Google Patents

Abstract

PURPOSE:To provide a laminate having not only moisture impermeability, air impermeability and transparency but also excellent ultraviolet blocking properties and conductivity. CONSTITUTION:A first metal oxide layer 2 with a thickness of 50-150nm composed of magnesium oxide, silicon oxide or aluminum oxide, a zinc oxide layer 3 with a thickness of 50-200nm and a second metal oxide layer with a thickness of 50-200nm are successively laminated on at least the single surface of a base film 1 having transparency. The zinc oxide layer has the blocking properties of ultraviolet rays with a wavelength of 400nm or less but, since it is easily deteriorated by oxygen, the zinc oxide layer is provided between the first and second metal oxide layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate used for producing packaging materials and the like. Furthermore, it is moisture-permeable, air-permeable, highly transparent in the visible light range, and
The present invention relates to a laminate having a conductivity that shields wavelengths in the ultraviolet region of m or less.

[0002]

2. Description of the Related Art In recent years, as a packaging material having both moisture resistance and air resistance, a laminate having a transparent substrate film and a metal oxide thin film such as silicon oxide, aluminum oxide or magnesium oxide on one surface thereof. A packaging material for making bags has been developed and put into practical use.

This is because silicon oxide is used in place of an opaque metal thin film layer such as an aluminum foil layer or an aluminum vapor-deposited layer that a laminate used for a conventional packaging material having both moisture permeation resistance and air permeation resistance has. By providing a transparent metal oxide thin film of aluminum oxide, magnesium oxide, or the like, in addition to the above-mentioned characteristics, the contents can be confirmed and transparency can be imparted.

However, since the laminated body provided with the transparent metal oxide thin film has almost no ultraviolet ray shielding function, the contents may be deteriorated by the ultraviolet rays. Therefore, an ultraviolet absorber made of metal or metal oxide
It is conceivable that the ultraviolet absorber is mixed with the base material film in the laminate or coated on the surface of the laminate to impart the ultraviolet blocking property, but the ultraviolet absorber is a colored one, and a large ultraviolet blocking property should be obtained. When the mixing amount or the coating amount is increased, the light transmittance of the laminated body (packaging material) in the visible region decreases.

On the other hand, since the metal oxide thin film does not have conductivity, if the content is a lightweight dielectric material, it may be difficult to take out the content from the packaging material due to the generation of static electricity. Therefore, it is conceivable that a conductivity-imparting agent composed of a metal or a metal oxide is mixed into the base material film in the laminate, or the surface of the laminate is coated to impart an ultraviolet blocking property. The imparting agent is also colored, and the light transmittance in the visible region of the laminate (packaging material) decreases as the amount of mixture or the amount of coat increases in order to obtain high conductivity.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the conventional laminated body,
It is an object of the invention to provide a laminate having moisture resistance, air resistance, and transparency, as well as excellent ultraviolet ray blocking property and conductivity.

[0007]

The invention according to claim 1 is
50n on at least one side of a transparent base film
a first metal oxide layer having a thickness of m to 150 nm;
A zinc oxide layer having a thickness of 50 nm to 200 nm and 5
It is a laminated body characterized by sequentially laminating a second metal oxide layer having a thickness of 0 nm to 200 nm.

The invention according to claim 2 is based on the invention according to claim 1, wherein a transparent resin layer having heat sealability is further provided on the second metal oxide layer. Is.

The present invention will be described in detail below. The transparent substrate film according to the present invention includes polyethylene terephthalate (PET), biaxially oriented polypropylene (OPP), biaxially oriented nylon (ONy), etc., which are used for usual packaging materials and the like. It has smoothness, mechanical strength, and dimensional stability. An additive may be added in order to maintain the adhesiveness with the thin film formed on the substrate film. The thickness is about 6 μm to 300 μm, and 12 μm to 50 μm is preferable for a packaging material. When appropriate, physical treatment such as corona treatment, low-temperature plasma treatment, ion bombardment treatment, or ozone treatment, or chemical treatment such as chemicals may be performed.

The first metal oxide layer according to the present invention is
This layer is formed by using a metal oxide such as magnesium oxide, silicon oxide, or aluminum oxide as a thin film forming material, and using a vacuum thin film forming method such as a PVD method such as a vacuum evaporation method, a sputtering method, an ion plating method or a CVD method. . Among the metal oxides, magnesium oxide is preferable from the viewpoint of productivity and transparency.

The thickness of the first metal oxide layer is 50.
It is preferably from nm to 150 nm. That is, 50
If the thickness is less than or equal to nm, moisture resistance from the base film side
If the air resistance is insufficient, and if it is 150 nm or more, it takes time to form a thin film and the flexibility is impaired, and cracks due to internal stress occur in the thin film, and moisture resistance and air resistance are likely to deteriorate.

The zinc oxide layer according to the present invention means PVD such as vacuum deposition method, sputtering method, ion plating method, etc., using zinc oxide as a thin film forming material on at least one surface of the above-mentioned transparent base material film. Method or a layer provided by a vacuum thin film forming method such as a CVD method.

Other conductive metal oxides include metal-doped tin oxide and indium-tin oxide, but tin oxide is slightly colored, and indium-tin oxide is Indium, which is a raw material, has a drawback that it is expensive, and is not suitable for a laminated body.

The method for forming the zinc oxide layer will be described in detail below.
Zinc oxide can be formed into a thin film by a normal vacuum vapor deposition method, but if it is left as it is, it becomes a thin film having metallic luster, and the light transmittance in the visible region may decrease. It is preferable to use a reactive vapor deposition method in which a plasma space generated by pressure is passed to deposit on a substrate.

Further, in order to improve the conductivity of the zinc oxide layer, it is effective to use a metal such as aluminum as a dopant for zinc oxide. In other words, with zinc oxide alone, when exposed to high temperatures in various atmospheres, the adsorbed oxygen trapped in zinc oxide becomes chemisorbed in the thin film due to the increase in temperature even in vacuum, resulting in a resistance value. However, the use of a metal as a dopant can prevent this. However, if a dopant is contained, the optical absorption edge will be shifted to the lower wavelength side, so addition of a large amount is not preferable.

The thickness of the zinc oxide layer is 50 nm to 2
00 nm. When the film thickness of the zinc oxide layer is 50 nm or less, the ultraviolet ray shielding ability is insufficient and the electric resistance value is large (several MΩ / □ or more). On the other hand, the film thickness is 200n
When it is m or more, cracks are likely to occur in the film due to internal stress, and as a result, moisture permeation resistance and air permeation resistance may be deteriorated. Further, the conductivity of the zinc oxide layer having the above-mentioned film thickness is good in the state of excess zinc.

Prior to the formation of the metal oxide layer, a transparent resin made of a transparent reducer such as urethane, polyvinylidene chloride or polyester may be provided as a protective layer on the zinc oxide layer in a thickness of 1 μm to 2 μm.

The zinc oxide layer is a substance whose performance is significantly deteriorated by the adsorption of moisture or oxygen in the air. Since it is difficult to use it as the outermost layer, a metal oxide layer is further provided. .

The second metal oxide layer according to the present invention is
A thin film forming material similar to that of the first metal oxide layer, and a layer provided by a similar vacuum thin film forming method.

The thickness of the second metal oxide layer is preferably 50 nm to 200 nm because it forms the outermost surface. That is, when the thickness is 50 nm or less, the moisture and air resistance is insufficient, and conversely, when the thickness is 200 nm or more, the flexibility is impaired and cracks due to internal stress occur in the thin film, and the moisture and air resistance is reduced. It will deteriorate.

The laminate produced by the above method may be laminated with a transparent resin layer having a heat-sealing property, if necessary. The laminating method may be either a dry laminating method or an extrusion laminating method. It is sufficient that the thickness of this layer is approximately 20 μm to 100 μm.

[0022]

The laminated body according to the present invention has a zinc oxide layer in its layer structure. Zinc oxide is a semiconductor with an intrinsic lattice defect and its energy gap is about 3.2 eV.
Is. Therefore, it has a property of blocking ultraviolet rays having a wavelength of 400 nm or less. However, when zinc oxide alone is coated as a thin film on a substrate film having transparency, when zinc oxide itself is exposed to high temperatures in various atmospheres, even when it is vacuumed, The trapped adsorbed oxygen becomes chemisorbed in the thin film due to the rise in temperature, and the resistance value increases.

Therefore, a zinc oxide layer is further provided between the first metal oxide layer and the second metal oxide layer made of at least one of magnesium oxide, silicon oxide and aluminum oxide. As mentioned above, zinc oxide is extremely sensitive to moisture and oxygen in the air by itself, and in order to maintain its properties, oxides such as magnesium oxide, silicon oxide, and aluminum oxide shield the layer in contact with the atmosphere. It can be inferred that the property can be retained.

Further, if a transparent resin layer having heat sealability is further provided on the metal oxide layer, heat sealability can be imparted to the laminate.

[0025]

EXAMPLES Next, the present invention will be specifically described with reference to experimental examples.

[Experimental Examples 1 to 4] As shown in FIG. 1, as a transparent base material film, a polyethylene terephthalate (Teijin GS) base material having a thickness of 50 μm was used.
A first metal oxide layer made of a magnesium oxide thin film having a thickness of 100 and 200 nm (referred to as Experimental Examples 1, 2, 3, and 4) was sequentially formed by a reactive vacuum deposition method.

More specifically, after evacuation to 1 × 10 ⁻⁶ Torr or less in a vacuum apparatus in which a base material film and magnesium oxide powder are set at predetermined positions in advance, magnesium oxide is heated and evaporated by an electron gun. Let 1
A magnesium oxide thin film (first metal oxide layer) was formed at a film forming rate of 00 nm / min.

Various measurements were performed on the laminate thus prepared. Oxygen transmission rate is 10
/ 50A (manufactured by Modern Control) at 20 ° C,
Under 100% RH conditions, the water vapor transmission rate was 40 ° C, 9 ° C using Permatran W6 (made by Modern Control).
It was measured under the condition of 0% RH. The results are shown in Table 1.

[0029]

[Table 1]

Note: Those marked with * in the comprehensive evaluation column are
After the environment resistance test, oxygen permeability and water vapor permeability are 50%
It has risen (deteriorated) above.

[0031] In addition, the overall evaluation, the oxygen transmission rate of just created is 1.5g / m ² / 24h or less, the water vapor transmission rate of 3cc
/ M ² / 24h to or less, 40 ° C., after environmental testing left in 90% RH storage atmosphere for 10 days, the oxygen permeability, deterioration of the water vapor transmission rate (increase) of the following items 50% ○, and more than that.

The light transmittance was measured with a double beam spectrophotometer UV-3100 (manufactured by Shimadzu Corporation) using air as a reference. The light transmittances in Experimental Examples 1 to 5 were almost the same as those in the case of the base film alone. The results are shown in Figure 5a. It can be seen from FIG. 5 that the laminates of Experimental Examples 1 to 5 have no effect of blocking ultraviolet rays having a wavelength of 400 nm or less.

Further, the resistance value was measured by the DC four-terminal method, but in any experimental example, the resistance value was very large (10 ¹⁰ Ω / □ or more), and the charge could not be removed.

Experimental Examples 5-9 As shown in FIG. 3 (FIG. 2 for Example 5), a 100 nm first metal oxide layer and a 100 nm first metal oxide layer were formed on the same substrate film as in Experimental Examples 1 to 4. 50 nm
Zinc oxide layer of 0, 50, 100, 200, 300n
A second metal oxide layer made of a magnesium oxide thin film having a thickness of m (Experimental Examples 5, 6, 7, 8, and 9) was sequentially formed by a reactive vacuum deposition method.

More specifically, after evacuation to 1 × 10 ⁻⁶ Torr or less in the vacuum device in which the base material film and the powders of magnesium oxide and zinc oxide are set at predetermined positions in advance, the magnesium oxide is irradiated with an electron gun. Was evaporated by heating to form a magnesium oxide thin film (first metal oxide layer) at a film forming rate of 100 nm / min. Next, the zinc oxide powder was heated and evaporated with an electron gun, and a conductive zinc oxide layer having a thickness of 50 nm was formed under the same film forming conditions as the first metal oxide layer. In that case, oxygen gas 6 × 10
^-4 Torr was introduced, and oxygen plasma (500 W) was generated by high frequency (13.56 MHz) discharge. further,
Magnesium oxide was heated and evaporated by an electron gun on the formed zinc oxide layer to form a magnesium oxide thin film (second metal oxide layer) at a film forming rate of 100 nm / min.

With respect to the laminated body thus produced,
Evaluation was performed in the same manner as in Experimental Examples 1 to 4. Table 1 shows the oxygen transmission rate and the water vapor transmission rate. In addition, the light transmittance is shown in FIG.
Shown in. From FIG. 5, the laminated bodies of Experimental Examples 5 to 9 have 400 nm.
It can be seen that the following ultraviolet rays have an effect of blocking about 60% (transmitting about 40%). Furthermore, the resistance value is several KΩ / □
It was below, and the charge could be removed. In Experimental Example 9, both the oxygen permeability and the water vapor permeability increased by 80% after the environment resistance test.

[Experimental Examples 10 to 14] A magnesium oxide thin film was formed on the same substrate film as in Experimental Examples 1 to 4.
A first metal oxide layer of 00 nm, a zinc oxide layer of 100 nm, and a magnesium oxide thin film having a thickness of 0, 50, 100, 200, 300 nm (Experimental Examples 10, 11, 12, 13, 14 respectively) The second metal oxide layer made of was sequentially formed by the same reactive vacuum deposition method as in Experimental Examples 5 to 9.

With respect to the laminated body thus prepared,
Evaluation was performed in the same manner as in Experimental Examples 1 to 4. Table 1 shows the oxygen transmission rate and the water vapor transmission rate. In addition, the light transmittance is shown in FIG.
Shown in. From FIG. 5, the laminates of Experimental Examples 10 to 14 are 400
Approximately 85% of ultraviolet rays of nm or less is blocked (about 15% is transmitted)
It turns out that there is an effect. Furthermore, the resistance value is several hundred Ω.
/ Square or less, and the charge could be removed. In addition,
In Experimental Example 14, both the oxygen permeability and the water vapor permeability increased by 75% after the environment resistance test.

[Experimental Examples 15 to 19] A magnesium oxide thin film was formed on the same base film as in Experimental Examples 1 to 4.
A first metal oxide layer having a thickness of 00 nm, a zinc oxide layer having a thickness of 200 nm, and a magnesium oxide thin film having a thickness of 0, 50, 100, 200, and 300 nm (Experimental Examples 15, 16, 17, 18, and 19, respectively). The second metal oxide layer made of was sequentially formed by the same reactive vacuum deposition method as in Experimental Examples 5 to 9.

With respect to the laminated body thus prepared,
Evaluation was performed in the same manner as in Experimental Examples 1 to 4. Table 1 shows the oxygen transmission rate and the water vapor transmission rate. In addition, the light transmittance is shown in FIG.
Shown in. From FIG. 5, the laminates of Experimental Examples 15 to 19 are 400
Approximately 85% of ultraviolet rays of nm or less is blocked (about 15% is transmitted)
It turns out that there is an effect. Furthermore, the resistance value is several hundred Ω.
/ Square or less, and the charge could be removed. In addition,
In Experimental Example 19, both the oxygen permeability and the water vapor permeability increased by 90% after the environment resistance test.

[Experimental Examples 20 to 24] 1 consisting of a magnesium oxide thin film on the same base film as in Experimental Examples 1 to 4
A first metal oxide layer having a thickness of 00 nm, a zinc oxide layer having a thickness of 300 nm, and a magnesium oxide thin film having a thickness of 0, 50, 100, 200, and 300 nm (Experimental Examples 20, 21, 22, 23, and 24, respectively). The second metal oxide layer made of was sequentially formed by the same reactive vacuum deposition method as in Experimental Examples 6 to 10.

With respect to the laminated body thus prepared,
Evaluation was performed in the same manner as in Experimental Examples 1 to 4. Table 1 shows the oxygen transmission rate and the water vapor transmission rate. In addition, the light transmittance is shown in FIG.
Shown in. From FIG. 5, the laminates of Experimental Examples 20 to 24 are 400
Approximately 85% of ultraviolet rays of nm or less is blocked (about 15% is transmitted)
It turns out that there is an effect. Furthermore, the resistance value is several hundred Ω.
/ Square or less, and the charge could be removed. In addition,
In Experimental Examples 20 to 24, both the oxygen permeability and the water vapor permeability increased by 80 to 100% after the environment resistance test.

[Experimental Examples 25 to 27] As shown in FIG. 4, unstretched polypropylene (CPP) 60 μm (Showlex Aroma U made by Showa Denko) was two-component cured on the laminates prepared in Experimental Examples 7, 12, and 17. A transparent resin layer was provided by laminating by dry lamination using a type urethane adhesive.

With respect to the laminated body thus prepared,
Evaluation was performed in the same manner as in Experimental Examples 1 to 4. Table 2 shows the oxygen transmission rate and the water vapor transmission rate. In addition, the light transmittance is shown in FIG.
Shown in. From FIG. 5, the laminates of Experimental Examples 25 to 27 are 400
Approximately 85% of ultraviolet rays of nm or less is blocked (about 15% is transmitted)
It turns out that there is an effect.

[0045]

[Table 2]

The water vapor transmission rate and the oxygen transmission rate of the obtained laminate were higher than the results of Experimental Examples 7, 12, and 17.

[0047]

The laminate according to the present invention has magnesium oxide on at least one side of a transparent base film.
Since the first metal oxide layer made of at least one of silicon oxide and aluminum oxide, the zinc oxide layer, and the second metal oxide layer are sequentially laminated, when used as a packaging material, the contents of It is possible to confirm, and it is needless to say that it is possible to obtain moisture-proof and air-proof property.Although it has the ability to shield ultraviolet rays, there is no danger of migration of the ultraviolet absorber to the contents or protrusion to the surface of the packaging material. Due to the conductivity, it is possible to prevent the contents from being attached to the inner wall due to the charging of the packaging material.

Further, the laminate according to the present invention can be used as an ultraviolet ray shielding film by providing a transparent adhesive layer on one side thereof and adhering it to the glass of a building.

[0049]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a laminated body according to an experimental example of the present invention.

FIG. 2 is a cross-sectional view of a laminated body according to an experimental example of the present invention.

FIG. 3 is a cross-sectional view of a laminated body according to an experimental example of the present invention.

FIG. 4 is a cross-sectional view of a laminated body according to an experimental example of the present invention.

FIG. 5 is a graph showing light transmittance.

[Explanation of symbols]

 1 Base Film 2 First Metal Oxide Layer 3 Zinc Oxide Layer 4 Second Metal Oxide Layer 5 Transparent Resin Layer

Claims (2)

[Claims] 1. A first metal oxide layer having a thickness of 50 nm to 150 nm on at least one side of a transparent substrate film, a zinc oxide layer having a thickness of 50 nm to 200 nm, and a layer of 50 nm to 200 nm. A laminated body, in which a second metal oxide layer having a thickness is sequentially laminated. 2. The laminate according to claim 1, further comprising a transparent resin layer having heat sealability provided on the second metal oxide layer.