JPH0858848A - Laminate - Google Patents

Abstract

(57) [Summary] To achieve this object, a magnesium oxide thin film layer of 30 to 300 nm and a two-component curing type adhesive layer are sequentially laminated on a substrate made of transparent plastic, and further, transparent plastic Provided is a laminate comprising a transparent barrier film having a metal oxide thin film layer of 10 to 200 nm laminated on a substrate. [Effect] It has flexibility and can prevent barrier deterioration due to cracks during post-processing such as slitting and bag making.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a gas barrier laminate used in the field of packaging foods, pharmaceuticals and the like.

[0002]

2. Description of the Related Art Recently, in the field of packaging materials, environmental protection has been an unavoidable problem. From the image of packaging material = trash, people are calling for easy incineration, avoiding excessive packaging, and recycling. A metal foil laminate film which is widely used as a gas barrier packaging material due to its high barrier property tends to be avoided because the residue after incineration becomes a problem. Further, the metal vapor deposition film cannot be distinguished from the metal foil laminate film at first glance, so that the demand for the transparent barrier film is increasing steadily.

A film in which a metal oxide thin film layer is provided on a transparent plastic substrate has transparency and barrier properties which cannot be achieved by a metal vapor deposition film.

In particular, a film using magnesium oxide as a metal oxide has a high oxygen barrier and a high water vapor barrier and is an effective barrier film.

However, since a thin film of magnesium oxide is weak against physical impact such as fir tree and lacks flexibility, cracks are formed in the film during post-processing such as slitter and bag making, and the barrier property is deteriorated. Have a point. For this reason, the handling of the film requires careful attention and hinders its versatility.

Further, since magnesium oxide is carbonized by moisture, when the storage atmosphere of the magnesium oxide thin film layer is high in humidity, water vapor penetrates with time from cracks such as cracks caused by fissures, carbonizes, and ages. The barrier deterioration phenomenon may occur due to.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and prevents barrier deterioration caused by the occurrence of cracks in post-processing such as slitters and bags, and protects against high humidity. It is an object of the present invention to provide a barrier laminate which is easy to handle and does not deteriorate with time even during storage.

[0008]

In order to achieve this object, 30 to 300 n are formed on a substrate made of transparent plastic.
m magnesium oxide thin film layer and two-component curing type adhesive layer are sequentially laminated, and further 10 to 2 on the transparent plastic substrate.
Provided is a laminate comprising a transparent barrier film having a metal oxide thin film layer of 00 nm laminated thereon.

Further, the metal oxide includes silicon oxide, aluminum oxide, tin oxide and calcium oxide.

Further, after a printing layer is laminated on one outer surface of the laminate having the structure of claim 1 or between the magnesium oxide thin film layer and the two-component curing adhesive layer of the laminate, a transparent primer layer is laminated, Alternatively, it is provided between the two-component curing type adhesive layer and the transparent barrier film. However, this is a more preferable form if it is applied to the laminated body of claim 2.

The present invention will be described in more detail by way of examples. Drawings 1-10 are sectional views of a layered product concerning the present invention.

Example 1 A biaxially stretched polyethylene terephthalate film (12 μm) was used as the plastic substrate 1 shown in FIG. 1, and a magnesium oxide thin film layer 2 (50) was used.
(nm) is laminated by an electron beam heating vapor deposition method, a urethane two-component curable adhesive layer 3 is further sandwiched, and a silicon oxide thin film layer 4 (on one side of a biaxially stretched polyethylene terephthalate film used as a transparent plastic substrate 5 ( (40 nm) was laminated by a resistance heating method, and a barrier film was laminated as a prototype with silicon oxide facing the adhesive layer side.

Example 2 A biaxially stretched polyethylene terephthalate film (12 μm) was used as the plastic substrate 1 shown in FIG. 2, and a magnesium oxide thin film layer 2 (50) was used.
of the silicon oxide thin film layer 4 on one side of the biaxially stretched polyethylene terephthalate film.
A prototype was prepared in which a barrier film obtained by laminating (40 nm) by a resistance heating method was laminated with a plastic substrate facing the adhesive layer side.

The plastic substrates 1 and 5 used in the present invention are those used as usual packaging materials for polyolefins, polyesters, polyamides, polyvinyl chlorides, polyimides, etc., or copolymers of these polymers. Although not limited thereto, a base material having transparency as a transparent barrier film is desirable. In particular, a biaxially stretched polyethylene terephthalate film is preferably used.

The thickness of the plastic film is 3 to 2
In the range of 00 μm, a thickness of 6 to 100 μm is desirable.
Further, there is no problem in containing additives and stabilizers (antistatic agent, ultraviolet absorber, plasticizer, lubricant, etc.). Further, there is no problem even if the film is subjected to surface treatment (corona treatment, plasma treatment, etc.).

Further, the magnesium oxide thin film 2 will be described. The magnesium oxide thin film is substantially magnesium oxide, and there is no problem even if it contains about 2 to 5% of impurities.

As a method for forming the magnesium oxide thin film layer, known methods such as a vacuum vapor deposition method, a sputtering method and an ion plating method can be used. Preferably a vacuum deposition method,
An electron beam heating method is particularly desirable.

The thickness of the magnesium oxide thin film is 30 to 3
00 nm is desirable, and if it is 30 nm or less, there is a problem in the continuity of the film, and if it is 300 nm or more, cracks easily occur in the film or flexibility decreases, so that it is preferably 45 to
It is 100 nm.

The two-component curable adhesive layer 3 will be described.
The two-component curing adhesive refers to a polyurethane two-component curing adhesive and is most commonly used for laminating plastic films by dry lamination. When the main agent composed of a polyol having a hydroxyl group terminal and the curing agent composed of a polyisocyanate are urethane-bonded, the reaction is cured.

Polyols include polyether type and polyester type. Since the polyether type polyol has an ether group or a methylene group, it is suitable for wetting.
It excels in low-temperature properties and hydrolysis resistance, but has a weak cohesive force and is inferior to polyester-based polyols in terms of adhesion to metals.
Since the polyester-based polyol is a combination of a dicarboxylic acid and a glycol component, it can have various performances such as control of molecular weight. However, since the ester group has poor hydrolysis resistance, those having a side chain or an aromatic ring that generally causes steric hindrance are used. These increase the Tg and cohesive strength of the adhesive and also increase the adhesive strength to the metal. In the laminate of the present invention, it is desirable to use a main component composed of a polyester polyol in terms of adhesion to metal.

The curing agent includes aromatic type such as tolylene diisocyanate and diphenylmethane diisocyanate and aliphatic type such as hexamethylene diisocyanate, isophorone diisocyanate and xylylene diisocyanate.
It is common to use an aromatic type for general applications such as snack packaging, and an aliphatic type for boiling and retort applications.

The metal oxide thin film layer 4 will be described. The metal oxide thin film layer is provided for the purpose of preventing the barrier deterioration caused by the lack of flexibility of the plastic film formed by forming the magnesium oxide thin film layer on the transparent plastic substrate. It is a metal oxide having gas barrier properties such as aluminum oxide, tin oxide, and calcium oxide and having transparency. The plastic film on which the magnesium oxide thin film layer is formed is a slitter, post-processing such as bag making, cracks are introduced into the magnesium oxide thin film layer, and water vapor penetrates with time from here,
Magnesium oxide is carbonated and the barrier deteriorates. By laminating a film having a metal oxide thin film layer, it is possible to prevent water vapor from entering a crack generated by post-processing, and consequently prevent barrier deterioration. Silicon oxide is preferable in terms of excellent gas barrier property and flexibility, but it is not particularly limited.

The film thickness of the metal oxide thin film layer varies depending on the type of metal oxide, but is preferably 10 to 200 nm, and if it is 10 nm or less, there is a problem in the continuity of the film.
If the thickness is 200 nm or more, cracks may easily occur in the film,
Since flexibility decreases, it is preferably 40 to 150 nm.
Is desirable.

As a method for forming the metal oxide thin film layer, known methods such as a vacuum vapor deposition method, a sputtering method and an ion plating method can be used. Preferably, it is a vacuum deposition method.

Continuing on, referring to FIGS.
10 will be described in detail.

Example 3 A trial construction was made in which the printed layer 6 was provided on the plastic substrate 5 which was the outermost layer of the laminate of Example 1. (See Drawing 3.)

<Embodiment 4> A trial construction was made in which the printed layer 6 was provided between the adhesive layer 3 and the silicon oxide thin film layer 4 of the laminate of Example 1. (See Drawing 4)

<Embodiment 5> The magnesium oxide thin film layer 2 of the laminate of Example 1 has a thickness of 100 nm, and the metal oxide thin film layer 4 is made of aluminum oxide instead of silicon oxide having a thickness of 50 nm by an electron beam heating method. It was deposited by. Further, a trial construction was made in which a printing layer 6 was provided between the adhesive layer 3 and the aluminum oxide thin film layer 4, and a primer layer 7 was provided between the magnesium oxide thin film layer 2 and the adhesive layer 3.
(See Drawing 5)

<Example 6> The thickness of the magnesium oxide thin film layer 2 of the laminated body of Example 1 was 100 nm, and tin oxide was 50 nm instead of silicon oxide as the metal oxide thin film layer 4.
Was deposited by the electron beam heating method. Further, a primer layer 7 is provided between the magnesium oxide thin film layer 2 and the adhesive layer 3,
A prototype in which the printing layer 6 was sequentially provided was manufactured. (See Drawing 6)

<Embodiment 7> A trial construction was made in which the printed layer 6 was provided on the silicon oxide thin film layer 4 which was the outermost layer of the laminate of Example 2. (See Drawing 7.)

<Embodiment 8> A trial construction was made in which the printed layer 6 was provided between the adhesive layer 3 and the plastic base material layer 5 of the laminate of Example 2. (See Drawing 8)

Example 9 In place of silicon oxide as the metal oxide thin film layer 4 of the laminated body of Example 2, tin oxide is used in an amount of 500.
It was vapor-deposited at a thickness of A by an electron beam heating method. Further, a trial construction was made in which a printed layer 6 was provided between the adhesive layer 3 and the tin oxide thin film layer 4, and a primer layer 7 was provided between the magnesium oxide thin film layer 2 and the adhesive layer 3. (See Drawing 9)

<Example 10> The magnesium oxide thin film layer 2 of the laminated body of Example 2 had a thickness of 90 nm, and the metal oxide thin film layer 4 was aluminum oxide instead of silicon oxide having a thickness of 50 nm and was subjected to an electron beam heating method. It was deposited by. Furthermore, a trial construction was made in which a primer layer 7 and a printing layer 6 were sequentially provided between the magnesium oxide thin film layer 2 and the adhesive layer 3.
(See Drawing 10)

The transparent primer layer 5 according to the present invention is provided between the magnesium oxide thin film layer and the two-component curing type adhesive layer, and is a machine for forming the magnesium oxide thin film layer when providing a printing layer or laminating. The purpose is to prevent barrier deterioration due to physical impact.

The resin used as the primer is polyvinyl chloride type, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral type, polymethylmethacrylic type, polyurethane type, polyether type, polyester type, polyamide type, nitrocellulose type, cellulose. It is a thermoplastic resin such as a derivative resin or a thermosetting resin such as a melamine resin or a urea resin, and is not particularly limited. It is also possible to mix a curing agent and the like to form a coating film having a high degree of crosslinking. The coating method is not particularly limited, but a gravure coating method of diluting with a solvent and coating is preferable in terms of simplicity. As the resin, a polyester-based resin is preferable because it has excellent wettability with magnesium oxide and gravure coating characteristics.

The ink used for the printing layer is a urethane type ink,
A mixture of a binder resin such as an acrylic resin, a nitrocellulose resin, a rubber resin, or a vinyl chloride resin with a pigment, a plasticizer, a drying agent, and a stabilizer is generally used. The present invention is not particularly limited to ink. The printing method includes an offset method, a gravure method, and a silk screen method, and is not particularly limited.

Comparative Example 1 A magnesium oxide thin film layer having a thickness of 50 nm was formed on one surface of a biaxially stretched polyester film having a thickness of 12 μm by an electron beam heating method.

Comparative Example 2 A silicon oxide thin film layer having a thickness of 40 nm was formed on one side of a biaxially stretched polyester film having a thickness of 12 μm by a resistance heating method.

Comparative Example 3 A magnesium oxide thin film layer having a thickness of 50 nm was formed on one surface of a biaxially stretched polyester film having a thickness of 12 μm by an electron beam heating method, and a urethane type two-component curable adhesive layer, a biaxially stretched polyester film were prepared. Films (12 μm) were sequentially laminated.

If necessary, a heat-sealable thermoplastic resin layer may be laminated on the laminated body laminated as described above,
It is also possible to stack a plurality of resins via an adhesive layer and use them.

[0041]

The barrier laminate of the present invention is a barrier in which a magnesium oxide thin film layer, a two-component curing adhesive layer, and a metal oxide thin film layer on a transparent plastic substrate are provided on one surface of a transparent plastic substrate. Since the flexible films are sequentially laminated, it has flexibility and can prevent barrier deterioration due to cracks during post-processing such as slitting and bag making.

[0042]

EXAMPLES The above examples were tested. <Test 1> The laminates of Examples 1, 2, 3, 4, 7, 8 and Comparative Examples 1, 2, 3 were observed 10 times with Gelbo Flex, and the oxygen permeability before and after the observation was measured.

<Test 2> Examples 1, 2, 3, 4, 7,
An unstretched polypropylene film (30 μm) was laminated on one surface of each of the laminates of Example 8 and Comparative Examples 1, 2, and 3 by a dry lamination method with a urethane two-component curing adhesive. The water vapor permeability of this laminate was measured with Permatran (manufactured by mocon). The measurement condition is 40 ° C.-90% RH.

A pouch with a four-sided seal was prepared using these laminates, about 15 g of calcium chloride was filled as the contents, and the pouch was stored for 1 month in an atmosphere of 40 ° C.-90% RH, and the weight change with time. Was measured. The water vapor permeability (g / m ² · day) was calculated from the area of this pouch.

<Test Results> The test results are summarized in Table 1.

[0046]

[Table 1]

[0047]

In the barrier laminate of the present invention, a magnesium oxide thin film layer, a two-component curable adhesive layer, and a metal oxide thin film layer on a transparent plastic substrate are provided on one side of a transparent plastic substrate. Since the barrier films are sequentially laminated, the transparent barrier packaging material has excellent flexibility and can withstand complicated handling during post-processing such as slitting and bag making, and is versatile.

[0048]

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing another embodiment of the present invention.

FIG. 4 is a schematic sectional view showing another embodiment of the present invention.

FIG. 5 is a schematic sectional view showing another embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing another embodiment of the present invention.

FIG. 7 is a schematic sectional view showing another embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view showing another embodiment of the present invention.

FIG. 9 is a schematic sectional view showing another embodiment of the present invention.

FIG. 10 is a schematic sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1,5-Transparent plastic substrate 2-Magnesium oxide thin film layer 3-Adhesive layer 4-Metal oxide thin film layer 6-Printing layer 7-Primer layer

Claims (5)

[Claims] 1. From 30 to 30 on a substrate made of transparent plastic.
A magnesium oxide thin film layer having a thickness of 300 nm and a two-component curing adhesive layer are sequentially laminated, and a transparent barrier film having a metal oxide thin film layer having a thickness of 10 to 200 nm laminated on a transparent plastic substrate is further laminated. A laminated body. 2. The laminate according to claim 1, wherein the metal oxide thin film layer is silicon oxide, aluminum oxide, tin oxide or calcium oxide. 3. A laminate according to claim 1, wherein a printing layer is provided on one outer surface of the laminate according to claim 1. 4. The laminate according to claim 1, wherein a transparent primer layer and a printing layer are sequentially laminated between the magnesium oxide thin film layer and the two-component curable adhesive layer. 5. The laminate according to claim 1, wherein a printing layer is provided between the two-component curable adhesive layer and the transparent barrier film.