JPH06192819A - Gas-barrier polymer film and its production - Google Patents

Abstract

PURPOSE:To improve the gas-barrier property and to improve the adhesion of a substrate to a thin film by forming a silicon oxide thin film on a transparent polymer-film substrate and specifying the steam permeability of the film and the peel strength of the thin film. CONSTITUTION:A thin film of SiOx (where 1.3<=x<=1.8) is formed in 200-1000A thickness on the substrate of a transparent film such as a polyacrylic film by high-frequency magnetron sputtering. In this case, the steam permeability of the film is controlled to <=1g/m<2>/day and the peel strength of the silicon oxide thin film to >=100g/cm by controlling the gaseous argon pressure, cathode magnetic flux density and supply power density in sputtering. Consequently, a gas-barrier polymer film is obtained with the adhesion of the silicon oxide thin film to the substrate improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas barrier film, a gas barrier polymer film suitably used as a substrate for a transparent conductive film of an electroluminescence element or a liquid crystal display element, and a method for producing the same. Specifically, it is a gas barrier polymer film having an excellent gas barrier property in which a silicon oxide film is formed on a polymer film substrate, in which the silicon oxide thin film has a strong adhesive force to the polymer film substrate. TECHNICAL FIELD The present invention relates to a polymer film and a method for manufacturing the same.

[0002]

2. Description of the Related Art A film in which a silicon oxide thin film is formed on a transparent polymer film substrate is used as a packaging material because it has a gas barrier property. Further, it is used for thin display devices such as electroluminescence devices and liquid crystal display devices. Is used as a substrate. When the transparent polymer film having this silicon oxide thin film is used as a substrate for a display element, a transparent thin film having conductivity is usually further deposited on the above silicon oxide thin film to form a transparent electrode. As a material for forming the transparent electrode, indium oxide containing 10% by weight of tin oxide is most often used in terms of conductivity, easiness of etching and the like.

Generally, as a material of the substrate used for the polymer having the above-mentioned silicon oxide thin film, polyarylate (P
AR), polyethylene terephthalate (PET), polycarbonate (PC), polyether sulfone (PE)
S), polysulfone, cellulose triacetate (T
AC) and transparent silicon oxide SiO _y
(1 <y <2) is formed.

This silicon oxide thin film is often formed by a vapor deposition method when the film is used as a packaging material and a sputtering method when it is used as a display element substrate. However, a gas barrier polymer film having a sufficient gas barrier property and a sufficiently strong adhesion of the silicon oxide thin film to the polymer film substrate has not been obtained.

If the transparent polymer film having the silicon oxide thin film formed thereon has insufficient gas barrier properties against water vapor and oxygen, particularly when it is used as a substrate for a display element, it may be affected by the permeated water vapor and oxygen, for example. Zinc sulfide forming the light emitting layer of the electroluminescent element and the liquid crystal of the liquid crystal display element are deteriorated.

If the adhesion of the silicon oxide thin film to the substrate is insufficient, for example, when a gas barrier polymer film is used as a substrate for a liquid crystal display device, a resist, for example, is used during the manufacturing process of the device. In the patterning process after coating, the alkali cleaning process, the polyimide alignment film baking process, etc., the transparent conductive film is separated from the polymer film substrate together with the silicon oxide thin film.

[0007]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and an object thereof is to provide a gas having a transparent polymer film substrate and a silicon oxide thin film formed thereon. It is an object of the present invention to provide a gas barrier polymer film having excellent gas barrier properties and good adhesion between the substrate and the thin film, and a method for producing the same.

[0008]

The gas barrier polymer film of the present invention comprises a transparent polymer film substrate, S
Thickness of iO _x (1.3 ≦ x ≦ 1.8) 200 to 10
A film having a silicon oxide thin film of 00 angstrom formed, wherein the water vapor permeability of the gas barrier polymer film is 1 g / m ² / day or less, and the silicon oxide thin film is peeled from the polymer film substrate. Strength is 100
It is g / cm or more, and thereby the above object is achieved.

The method for producing a gas barrier polymer film of the present invention comprises a polymer film substrate on which SiO _x (1.3 ≦ x ≦) is formed by a high frequency magnetron sputtering method.
A method for producing a gas barrier polymer film including a step of forming a silicon oxide thin film according to 1.8), wherein an argon gas pressure in the high frequency magnetron sputtering method is 0.5 to 5 mTorr, and a cathode magnetic flux density is 2.
00-400 gauss, input power density 1-4 W / cm ²
The above-mentioned object is achieved by carrying out under the conditions of.

Examples of the transparent polymer film substrate used for the gas barrier polymer film of the present invention include polyarylate (PAR), polyethylene terephthalate (PET), polycarbonate (PC), polyether sulfone (PES), poly Sulfone, polyamide,
A film or sheet made of cellulose triacetate (TAC) or the like having a good surface smoothness is mentioned, and a polyarylate film or sheet is particularly preferably used because it is also excellent in heat resistance. The thickness of the substrate is
It is preferably about 20 μm to 1 mm, more preferably 7
It is about 5 to 125 μm. Further, a film having a transparency shown by a light transmittance described later is preferably 85% or more, more preferably 90% or more.

The polymer film substrate is obtained by molding the above material into a film by an extrusion method, a casting method or the like. In particular, when molding using the casting method,
It is preferable because the substrate has excellent surface smoothness and a substrate suitable for optical use can be obtained.

The silicon oxide thin film formed on the polymer film substrate is a thin film made of SiO _x (1.3 ≦ x ≦ 1.8). When x exceeds 1.8, the gas barrier property of the obtained gas barrier polymer film is inferior.
If it is less than 3, the transparency is poor. The thickness of this silicon oxide thin film is 200 to 1000 angstroms. Thickness is 2
If it is less than 00 Å, the gas barrier property of the obtained gas barrier polymer film is inferior, and if it exceeds 1000 Å, cracks are likely to occur in the silicon oxide thin film.

The silicon oxide thin film is formed on the polymer film substrate, preferably by the following sputtering method. If the surface of the substrate is cleaned by a dry process such as argon discharge treatment before sputtering, the adhesion between the silicon oxide thin film and the substrate can be further improved.

As the sputtering method, a high frequency sputtering method is used. Particularly, the high frequency magnetron sputtering method is preferably used.

As the target, a sintered target of SiO _x (1.3 ≦ x ≦ 1.8) having the same composition ratio x as the desired silicon oxide thin film formed on the polymer film substrate is used. A silicon oxide thin film having a composition ratio x can be obtained.

As the cathode magnet, a ferrite magnet,
Rare earth magnets such as Sm-Co alloy magnets and Nd-Fe alloy magnets are used, and the use of ferrite magnets is preferable because a film excellent in adhesion of silicon oxide can be obtained.

The cathode magnetic flux density, that is, the magnetic flux density on the target surface is 200 to 400 gauss. If the magnetic flux density is less than 200 Gauss, stable magnetron discharge cannot be performed, and thus the rate at which silicon oxide is deposited on the polymer film substrate becomes slow. If the magnetic flux density exceeds 400 gausses, sufficient adhesion of the obtained silicon oxide thin film to the polymer film substrate cannot be obtained.

Argon gas is used as the discharge gas, and the argon gas pressure is 0.5 to 5 mTorr. When the argon gas pressure is less than 0.5 mTorr, the discharge is not stable, and when it exceeds 5 mTorr, the gas barrier property of the obtained gas barrier polymer film is poor.

The input power density is 1 to 4 W / cm ² .
Here, the input power density refers to the input power per unit area of the target. The higher the input power density, the faster the film formation speed of the obtained silicon oxide thin film and the stronger the adhesion to the polymer film substrate. However, if the input power density exceeds 4 W / cm ² , the cooling of the target will not catch up. However, the target cracks, which is not preferable.

The temperature of the polymer film substrate is appropriately selected from room temperature to the heat resistant temperature of the film, and is generally about 15
It is about 0 ° C or lower. The influence of the difference in substrate temperature on the gas barrier property of the produced gas barrier polymer film and the adhesive force between the polymer film substrate and the silicon oxide thin film is relatively small.

Thus, a silicon oxide thin film made of SiO _x (1.3 ≦ x ≦ 1.8) is formed on the transparent polymer film substrate. By appropriately controlling the conditions for forming the thin film, a thin film having a thickness of 200 to 1000 angstroms, a predetermined water vapor transmission rate, and high adhesion is formed on the substrate. The gas barrier polymer film of the present invention thus obtained has excellent gas barrier properties. The gas barrier property is evaluated by the water vapor transmission rate described later, and the water vapor transmission rate at 40 ° C. is 1 g / m ² / day or less. This film also exhibits excellent gas barrier properties against oxygen, has an oxygen gas permeability of 5 ml / m ² / day or less, and easily obtains a gas barrier polymer film of about 1 ml / m ² / day. be able to. Since the gas barrier polymer film of the present invention has the silicon oxide thin film, it has excellent resistance to organic chemicals that dissolve the polymer film substrate.

Further, the gas barrier polymer film of the present invention has a strong adhesion of the silicon oxide thin film to the polymer film substrate. The adhesion of the silicon oxide thin film to the polymer film substrate is determined by the 90-degree peeling method JIS-C-2 described later.
The peel strength according to 107 is 100 g / cm or more, and it is easy to obtain a gas barrier polymer film having a peel strength of about 300 g / cm. According to the present invention, a gas barrier polymer film having good adhesion of the silicon oxide thin film to the polymer film substrate is thus obtained.

By forming a transparent conductive film on at least a part of the silicon oxide thin film of the film having the silicon oxide thin film, a transparent conductive film having an excellent gas barrier property can be obtained. Examples of the transparent conductive film include indium oxide containing 10% or less of tin oxide. As a method of forming the transparent conductive film, a direct current sputtering method can be mentioned, and it can be formed subsequent to the formation of the silicon oxide thin film. This sputtering is performed under the conditions that stress strain does not occur in the silicon oxide thin film and does not affect the adhesion of the silicon oxide thin film to the substrate, the argon gas pressure is 3 to 7 mTorr, and the target input power density is 1
It can be performed under the condition of W / cm ² .

The gas barrier polymer film on which the transparent conductive film is formed has a large adhesive force between the silicon oxide thin film and the polymer film substrate. Therefore, even when it is used as a substrate of a liquid crystal cell, the silicon oxide thin film cracks. Does not occur or peels off from the polymer film substrate.

The film of the present invention has an excellent gas barrier property, and since the silicon oxide thin film is difficult to peel off from the substrate, a film having a conductive thin film is suitable for various kinds of packaging requiring the gas barrier property. It can be suitably used for a transparent electrode in a luminescence device, a liquid crystal display device, etc. and other uses.

[0026]

The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these.

Example 1 A polymer film was produced as follows by using a high frequency magnetron sputtering method. In the high frequency magnetron sputtering machine used, the substrate holder facing the target had a structure in which it was water-cooled from the back surface, and the distance between the substrate holder and the target was 7 cm. A 75 μm thick polyarylate transparent film (hereinafter referred to as a polyarylate substrate) was used as the polymer film substrate, and a 6-inch diameter sintered target made of SiO _1.5 was used as the target. A ferrite magnet is used as the cathode magnet,
The cathode magnetic flux density on the target surface was set to 250 gauss.

First, the polyarylate substrate was fixed on the substrate holder, and the pressure in the sputtering chamber was 2 × 1.
It was evacuated to 0 ^-6 Torr, and then argon was introduced as a discharge gas to 1 mTorr. A high-frequency power of 500 W was applied so that the applied power density was 2.7 W / cm ^2, and sputtering was performed for 1 minute to form a silicon oxide thin film with a thickness of 300 Å on the polyarylate substrate, thereby forming a gas barrier property. A polymer film was obtained.
The gas barrier polymer film thus obtained was evaluated by the following tests. The results are shown in Table 1.

Peel strength: Evaluated by the 90 degree peeling method based on JIS-C-2107. As shown in Figure 1,
The polymer film substrate 2 on which the silicon oxide thin film 1 is formed is cut into strips having a width w of 1 cm, and two strips of the same type are made so that the silicon oxide thin films 1 and 1 are inside each other and the epoxy resin 3 is used. Glued After the completion of the adhesion, one of the strips of the polymer film substrate 2 was peeled off in the direction of 90 degrees with respect to the adhesion surface as indicated by the arrow in the figure, and the pulling force at that time was taken as the peel strength. The unit is g / cm. Water vapor transmission rate: The water vapor transmission rate at 40 ° C. was measured by the moisture permeation test method (cup method) of the moisture-proof packaging material of JIS-Z-0208. Light transmittance: The light transmittance at a wavelength of 550 nm was measured by absorptiometry.

(Examples 2 to 4) A gas barrier polymer film was prepared in the same manner as in Example 1 except that the input power density was set to the value shown in Table 1 and in the same manner as in Example 1. evaluated. The results are shown in Table 1.

Comparative Examples 1 and 2 The same procedure as in Example 1 was carried out except that the input power density was set to the value shown in Table 1. However, in Comparative Example 1, target cracking occurred and the silicon oxide thin film could not be formed. The gas barrier polymer film of Comparative Example 2 was evaluated in the same manner as in Example 1.
The results are shown in Table 1.

[0032]

[Table 1]

Comparative Examples 3 and 4 Sm as a cathode magnet
-Using a Co alloy magnet, the magnetic flux density on the target is 50
A gas-barrier polymer film was produced in the same manner as in Example 1 except that it was 0 Gauss, and was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0034]

[Table 2]

Example 5 Indium oxide containing 10% SnO ₂ was used as a target, and the argon gas pressure was 5%.
DC sputtering was performed under the conditions of mTorr and DC input power density of 1 W / cm ² , and a thickness of 10 was formed on the silicon oxide thin film of the gas barrier polymer film obtained in Example 1.
A transparent conductive film of indium oxide having a thickness of 00 angstrom was formed to obtain a transparent conductive film with a gas barrier film base.
The sheet resistance of the obtained transparent conductive film was 35 Ω / □. With respect to this transparent conductive film with a gas barrier film foundation, the peel strength of the silicon oxide thin film from the polymer film substrate was measured in the same manner as in Example 1, and as a result, 150 g.
/ Cm, indicating strong adhesion.

[0036]

According to the present invention, it is possible to provide a gas barrier polymer film having a silicon oxide film formed on a polymer film substrate, excellent gas barrier properties, and good transparency. . In this gas barrier polymer film, the adhesion between the silicon oxide thin film and the polymer film substrate is strong, and cracks do not occur in the manufacturing process and the processing process.

The gas barrier polymer film of the present invention is preferably used as a substrate for an electroluminescence element or a liquid crystal display element, and a conductive film in which a conductive thin film is formed on a silicon oxide thin film is used as a packaging material. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a peeled state of a substrate in a peel strength test for evaluating the adhesion between a polymer film substrate and a silicon oxide thin film.

[Explanation of symbols]

 1 Silicon oxide thin film 2 Polymer film substrate 3 Epoxy resin layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Saiki 4-6-1 Hojocho, Toyonaka City, Osaka Prefecture Rene Toyonaka 121

Claims (4)

[Claims] 1. A transparent polymer film substrate on which SiO _{x is formed.}
A gas barrier polymer film having a silicon oxide thin film of (1.3 ≦ x ≦ 1.8) and a thickness of 200 to 1000 angstrom, wherein the water vapor permeability of the gas barrier polymer film is 1 g. / M ² / day or less,
A polymer film having gas barrier properties, wherein the peel strength of the silicon oxide thin film from the polymer film substrate is 100 g / cm or more. 2. At least a part of the silicon oxide thin film,
The gas barrier polymer film according to claim 1, wherein a transparent conductive film is formed. 3. The gas barrier polymer film according to claim 1, wherein the polymer film substrate is made of polyarylate. 4. SiO _x (1.3 ≦ x ≦) on a polymer film substrate by a high frequency magnetron sputtering method.
A method for producing a gas barrier polymer film comprising the step of forming a silicon oxide thin film according to 1.8), wherein the argon gas pressure in the high frequency magnetron sputtering method is 0.5 to 5 mTorr, and the cathode magnetic flux density is 200. ~ 400 gauss, input power density 1-4 W / cm ²
A method for producing a gas barrier polymer film, which is carried out under the conditions of.