JPH08323912A - Transparent conductive laminated film - Google Patents

Abstract

PURPOSE: To obtain a good liquid crystal display element not damaging gas barrier properties even under a high humidity atmosphere. CONSTITUTION: An org. resin gas barrier layer is laminated on the single surface of a polyether sulfone film through an adhesive layer and a layer composed of an epoxy thermosetting resin or an acrylic ultraviolet curable resin is further formed thereon as a protective coating layer and a layer composed of an acrylic ultraviolet curable resin is provided on the other single layer of the PES film as an undercoat layer and, further, a transparent conductive layer based on indium oxide is provided thereon to form a transparent conductive plastic film. In this plastic film, the gas barrier layer is formed by laminating two or more layers respectively composed of a polyvinyl alcohol resin and an ethylene/vinyl alcohol copolymer with ethylene content of 20-50mol% and the outermost layer of the org. resin gas barrier layer is composed of an ethylene/vinyl alcohol copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to films for electronic devices such as EL devices and LCD devices, and more particularly to an electrode substrate for manufacturing a liquid crystal cell.

[0002]

2. Description of the Related Art As transparent conductors, those having tin oxide or indium oxide films formed on a glass substrate have been known for a long time, and are now widely used for electrodes of various liquid crystal displays and transparent surface heating elements. Has been done. On the other hand, the transparent conductive film replaces the conventional glass substrate with a polymer film and is thin, lightweight, flexible without cracks, has good workability, and has a large area. Therefore, it is particularly promising as an electrode material for liquid crystals. In Japanese Patent Laid-Open No. 61-86252, an anchor coat layer using a urethane resin is provided on one surface of a PES film, and a polyvinyl alcohol resin is laminated as a gas barrier layer, and a thermosetting resin or a protective coating is used as a protective coat. A transparent laminated conductive film for liquid crystal in which an ultraviolet curable resin is formed, an acrylic ultraviolet curable resin is provided on the other side of the PES film, and a conductive layer containing indium oxide as a main component is further provided thereon. Is disclosed.

When the above-mentioned film substrate is used for liquid crystal applications, it must have a function of preventing the permeation of air from the film side. When air permeates, air bubbles are generated in the liquid crystal, which is a fatal obstacle in appearance. Therefore, in order to make a glass substrate into a polymer film, it cannot be used for liquid crystal applications unless air permeation is prevented. Here, a base film capable of trapping air may be used as the prevention method, but the birefringence which is the most preferable condition when used for liquid crystal or the like is within 40 degrees in terms of phase difference and the photoelastic constant is 2.0 mm. / Kg or less, PES is an amorphous polymer in order to satisfy high heat resistance
It cannot be achieved without a film. However, the air permeability of these amorphous polymer films is generally large,
It is difficult to prevent liquid crystal deterioration, and a gas barrier layer is required on this base film. As the organic substance layer having the best gas barrier property, there are polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer, cellulose type, polyacrylonitrile type, polyvinylidene chloride type, polyamide type resin, etc. A polyvinyl alcohol resin having high strength and a high functional group concentration is most preferable. However, since the polyvinyl alcohol resin is highly hydrophilic, water adheres to it under high humidity to break hydrogen bonds, impair the airtightness of the structure, and drastically lower the gas barrier property. Also, if a resin other than polyvinyl alcohol is used, it is necessary to increase the film thickness considerably.
Problems such as curling due to internal stress and heat resistance occur.

[0004]

Under the circumstances described above, the present invention provides a transparent conductive material in which deterioration of gas barrier property under high humidity is improved by laminating a polyvinyl alcohol resin and an ethylene-vinyl alcohol copolymer. It is intended to provide a laminated film.

[0005]

According to the present invention, an organic resin gas barrier layer (3) is laminated on at least one surface of a polyether sulfone film (hereinafter abbreviated as PES film) (1) via an adhesive layer (2). Further, an epoxy thermosetting resin or an acrylic UV curable resin is formed as the protective coat layer (4), and the acrylic UV curable resin is provided as an undercoat layer (5) on the other side of the PES film, Furthermore, a transparent conductive layer containing indium oxide as a main component (6)
A transparent conductive plastic film provided with, wherein the gas barrier layer comprises two or more layers of a polyvinyl alcohol resin (3a) and an ethylene-vinyl alcohol copolymer (3b) having an ethylene content of 20 to 50 mol%. A transparent conductive laminated film characterized by being laminated, and the outermost layer of the organic resin gas barrier layer (3) being an ethylene-vinyl alcohol copolymer (3b).

The PES film (1) of the present invention serves as a base material for a transparent conductive film and has a mechanical strength,
This film must be used in terms of optical characteristics and heat resistance. The thickness of the film is 50 to 300 μm,
It is preferably 75 to 125 μm. The adhesive layer (2) is obtained by applying a resin varnish and drying to remove the solvent. At this time, the resin system is preferably a resin system having film-forming properties after removing the solvent, that is, a varnish to which a solid resin is added, from the viewpoint of uniform coating, and specifically, a urethane resin can be mentioned, and a polyester type and a polyether type can be mentioned. However, the polyester type is generally preferable from the viewpoint of heat resistance and adhesiveness. As a method for forming the adhesive layer on the substrate, there are a gravure coating method, a reverse roll coating method, a kiss roll coating method and the like, and any method can be cured within 5 minutes in consideration of industrial production. Is desirable.

The gas barrier layer (3) has been carefully studied with a focus on obtaining a sufficient gas barrier property under high humidity, heat resistance, and curling characteristics, and as a result, a polyvinyl alcohol resin and a chemical structural property have been obtained. It was found that good results were obtained by using an ethylene-vinyl alcohol copolymer having a small humidity dependence similar to that of the above. In this case, the ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 50% is used. In terms of the layer structure, the polyvinyl alcohol resin layer is laminated with an ethylene-vinyl alcohol copolymer layer having a lower hygroscopic property than this layer, whereby the gas barrier layer is less likely to be affected by humidity. . The gas barrier layer is preferably formed by the same method as that of the adhesive layer (2). It should be noted that this formed film must also be substantially transparent and optically isotropic. The thickness of the barrier layer is not particularly limited, but from the viewpoint of performance, if the thickness is too thin, the performance as a barrier coat cannot be expected, and therefore 1
A thickness of μm or more is necessary. On the other hand, if the thickness exceeds 20 μm on one surface, the stress is strong and problems such as curling occur.

Next, the protective coating layer (4) to be laminated on the above gas barrier layer has the ability to withstand the etching treatment of the conductive film.
Further, the drying and curing temperature is 170 ° C. or lower, which is the discoloration start temperature of the polyvinyl alcohol resin, and it is necessary that the transparency and solvent resistance are excellent. As long as the above conditions are satisfied, either an organic substance or an inorganic substance may be used, but it is preferable to coat the organic substance at low cost, and specific examples thereof include an epoxy thermosetting resin and an acrylic ultraviolet curing resin. The protective coat layer is also preferably formed by the same method as in the case of the adhesive layer (2). It should be noted that this formed film must also be substantially transparent and optically isotropic.

Next, before forming a coating film containing indium oxide as a main component as a conductive layer, an undercoat layer is formed on the PES film for the purpose of improving scratch resistance, alkali resistance and the like.
Provide (5). The reason for this is that the transparent conductive film is formed by forming a conductive film on the polymer film by a vacuum deposition method, an ion plating method or a sputtering method, and the conductive film is an oxide containing indium as a main component. In many cases, the film thickness is made thin because high transparency is required in addition to conductivity. This is because scratch resistance for preventing disconnection due to scratches and durability against alkali treatment in the pattern processing step are required in the processing step of the transparent conductive film. Specifically, an acrylic ultraviolet curable resin is most desirable, and the method for forming the layer is preferably the same as that for the adhesive layer (2).

Finally, a transparent conductive layer (6) is formed on the coating. The transparent conductive layer is a thin film of a metal oxide, such as indium oxide, tin oxide, cadmium oxide, etc., and it is particularly preferable to form a thin film of indium oxide containing 5 to 10% by weight of tin oxide. These film thicknesses can be appropriately selected within the range of 50 to 2000Å. These thin films are formed by a known means such as a sputtering method or an ion plating method. Thus, a transparent conductive film was obtained which had no deterioration in gas barrier property even under high humidity.

[0011]

【Example】

<< Example 1 >> FIG. 2 is a schematic view of a transparent conductive film of the present invention, and shows a state in which a transparent conductive layer (6) is provided. The PES film (1) as a base material is formed by a melt extrusion method. The thickness is 100 μm, the retardation value is 10 nm or less, and the visible light transmittance is 90%. A urethane resin [Takenate A-3, Takeda Pharmaceutical Co., Ltd.] was uniformly applied to one side of the substrate (1) to a thickness of 2 μm by a roll coater method. Polyvinyl alcohol resin [Kuraray Poval # 117] (Co., Ltd.) was coated on the adhesive layer to a thickness of 3 μm, and an ethylene-vinyl alcohol copolymer was further coated thereon to a thickness of 12 μm. Then, an epoxy resin [bisphenol A type epoxy resin with polythiol as a curing agent] was applied thereon to a thickness of 3 μm as a protective coat. Further, as an undercoat of the conductive layer, an epoxy acrylate resin [Showa Polymer Co., Ltd. Lipoxy VR-60] is used.
Was coated on the other PES film surface to a thickness of 3 μm. The physical properties of the substrate obtained here are shown in FIG. And
Further, a transparent conductive laminated film was prepared in which indium oxide was provided in a thickness of 250 Å by a sputtering method.

Comparative Example 1 The same operation as in Example 1 was carried out except that the gas barrier layer provided on the adhesive layer was formed of polyvinyl alcohol resin to a thickness of 15 μm. << Comparative Example 2 >> In Example 1, the gas barrier layer provided on the adhesive layer was made of ethylene-vinyl alcohol copolymer.
The same operation was carried out except that a polyvinyl alcohol resin was applied to a thickness of 2 μm and a polyvinyl alcohol resin was formed thereon to a thickness of 3 μm.

[0013]

EFFECT OF THE INVENTION The transparent conductive laminated film obtained by using this can obtain a good liquid crystal display device without impairing the gas barrier property even in a high humidity atmosphere.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between relative humidity and oxygen permeation amount in Example 1 and each comparative example.

FIG. 2 is a cross-sectional view of a transparent conductive film of the present invention, showing a state in which a transparent conductive layer (6) is laminated.

[Explanation of symbols]

 1 PES film 2 Adhesive layer 3 Gas barrier layer 3a Polyvinyl alcohol resin 3b Ethylene-polyvinyl alcohol copolymer 4 Protective coat layer 5 Undercoat layer 6 Transparent conductive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08J 7/04 CEZ C08J 7/04 CEZP C08L 29/04 LDM C08L 29/04 LDM LGW LGW 81/06 LRF 81/06 LRF G02F 1/1333 500 G02F 1/1333 500 H01B 5/14 H01B 5/14 A

Claims (1)

[Claims] 1. An organic resin gas barrier layer (3) is laminated on one surface of a polyether sulfone film (1) via an adhesive layer (2), and an epoxy thermosetting resin is further used as a protective coat layer (4). Or form an acrylic UV curable resin,
A transparent conductive plastic film in which an acrylic UV curable resin is provided as an undercoat layer (5) on the other side of the PES film, and a transparent conductive layer (6) containing indium oxide as a main component is further provided. The gas barrier layer comprises an organic resin gas barrier layer in which two or more layers of the polyvinyl alcohol resin (3a) and the ethylene-vinyl alcohol copolymer (3b) having an ethylene content of 20 to 50 mol% are laminated.
The outermost layer of (3) is the ethylene-vinyl alcohol copolymer (3
b) A transparent conductive laminated film characterized in that