JPS6050592B2 - Conductive laminated film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester film having a transparent conductive coating.

More specifically, both sides of the polyester film are coated with a first layer made of a hardened curable polymer,
The present invention further relates to a conductive laminated film in which a transparent and conductive second layer is formed on one or both sides of the film.

Such conductive laminated films include a so-called transparent conductive film in which the base material itself is transparent, and a so-called transparent conductive film in which the base material itself is not transparent, but a transparent and conductive film is formed on it, and the base material is colored or printed. figures drawn by the means of
There are conductive laminated films with visible patterns, letters, etc.

Conventionally, as a transparent conductive material, for example, "Nesa Glass", which is a film of tin oxide formed on a heat-resistant material such as glass or quartz using a vapor phase decomposition method, has been mainly used.
If the substrate is glass, it is not flexible.

Therefore, it has disadvantages such as not being able to be produced continuously, not having good processing properties such as punching and cutting, low impact resistance, being heavy, and having poor dielectric properties, and it cannot be rolled up like magnetic tape or photographic film. This made it difficult to use it as an information recording medium. Most of these drawbacks can be overcome by using a polymer film as the support for the transparent conductive coating, but polymer materials generally do not have good heat resistance, so methods that can be applied to polymer materials are limited. Many of them are vacuum evaporation, reactive evaporation, ion blating,
Vacuum-based methods such as sputtering have been mainly used. A polyester film is preferably used as the base material of the conductive laminated film produced by this method from the viewpoints of dimensional stability and mechanical strength, especially from the viewpoint of heat resistance. The following types of conductive laminated films based on polyester films are known.

(1) Gold, silver, parallax on polyester film
A conductive laminated film made of a thin film of metal such as dium or aluminum. (2) On the polyester film,
A conductive laminated film made of a thin film of metal compounds whose main ingredients are copper iodide, indium oxide, tin oxide, titanium oxide, cadmium oxide, etc.

(3) A conductive laminated film according to (1) or (2) above, in which a layer mainly for the purpose of improving adhesiveness is provided between the polyester film and the transparent conductive layer.

These conductive laminated films are used for various purposes depending on their properties, especially transparency and conductivity. When used in applications that require the use of a film, low molecular weight substances, especially oligomers, are generated from the film, impairing its transparency, making it impossible to use the film at all or limiting its range of use. It had An example of the former occurs when a transparent electrode is incorporated into each element, such as a solid-state light emitting element, a photoelectric conversion element, or an EL display. The process of forming these elements requires a high temperature process, and oligomers are generated from the polyester film at such high temperatures, impairing its transparency.
An oligomer removal step was necessary. Examples of the latter include windshields of cars and airplanes, signal lights,
It is sometimes used to prevent condensation and freezing in frozen showcases, etc., and as a surface heating element for thermoplastic coatings. In such applications, since the conductive film is passed through and its heat generating effect is utilized, the generation of oligomers is unavoidable, and since the film is used repeatedly, it has been impossible to remove the oligomers. The present inventor has proposed that by forming a curable polymer layer on both sides of a polyester film, and forming a transparent conductive film on both sides or one side thereof, this drawback of the conventional method can be overcome by the cured curable polymer layer. discovered that a conductive laminated film with excellent heat resistance could be obtained.
This has led to the present invention. That is, the present invention provides a laminated film in which a transparent and conductive layer 2 is formed on at least one side of a polyester film, and the layer 2 is a layer 1 of a curable polymer formed and cured on both sides of the polyester film. This is a conductive laminated film characterized in that it is formed with at least one layer 1 interposed therebetween. Examples of the polyester film in the present invention include polyethylene terephthalate, polyethylene naphthalate,
Films made of polybutylene terephthalate are commonly used.

These films are made by melt extrusion, calendering, casting, etc., and in addition to polyester, curing catalysts, adhesion promoters, wettability improvers, stabilizers, antioxidants, and lubricants are added as necessary. It is acceptable even if additives such as thickeners, pigments, etc. are mixed in. Furthermore, it may be a composite film laminated with one or more other polymeric films, a copolymerized polyester, or a blended film with other polymers. Further, a polyester film subjected to stretching processing, particularly biaxial stretching processing, is particularly preferable because it has excellent mechanical properties, thermal properties, optical properties, and dimensional stability. In addition, it is also possible to perform physical and chemical surface modification treatments such as corona treatment, matting treatment, steam treatment, and alkali treatment, or to provide a surface modification layer, if necessary. Further, figures, characters, patterns, etc. may be drawn on the surface. The curable polymer used in the present invention can be heat cured, ultraviolet cured, β
Polymers that are cured or crosslinked by radiation curing, such as rays or gamma rays, include xylene resins, melamine resins, sulfonamide resins, alkyd resins, epoxy resins, unsaturated polyester resins, and organometallic compounds, among others. Organometallic compounds containing metals such as silicon, titanium, and aluminum are particularly preferred for the film targeted by the present invention.

Examples of such polymers include metal halides having the general formula MnXm (where M is a metal, X is a halogen, and M and n are positive integers), which easily decomposes and hardens by heating. to form a polymer film. Examples of metal halides include Ticl4, A
Examples include lcl3, Zrcl4, and Incl4.
Also used is a metal alkyl ester represented by the general formula MlOrnRn (where M is a metal, R is an alkyl group, and 1, m, and n are positive integers). Furthermore, silicon-containing organometallic compounds represented by the following general formula are particularly preferred. [However, in the formula, R1 is -0-11s1I<' [R5 and R6 are hydrogen or an alkyl group having 1 to 4 carbon atoms] or an alkylol compound thereof, a polyamino group, and 1CH, -Cl9bevY2 is an alkyl group having 1 to 12 carbon atoms; R3 and R4 are alkyl groups having 1 to 4 carbon atoms; X and y are integers of 1 to 12: W
, z is an integer of 0 to 2, z is an integer of 1 to 3, and satisfies w+z=3] Furthermore, the general formula RnSjXm (where R is methyl, ethyl, propyl, butyl, vinyl, phenyl, methacryloxy, methacryloxypropyl) Organic groups such as;
X is a halogen group, alkoxy group or acyl group; N, m
There is a prepolymer obtained by hydrolyzing one or more kinds of compounds represented by the formula (each is an integer of 0 to 4 and satisfies n+m=4).

The thermosetting polymer may be used alone or mixed with two or more types of thermosetting polymers as necessary, and may also be added with a curing catalyst, adhesion promoter, wettability improver, plasticizer, stabilizer, etc. as necessary. The composition can be prepared by dissolving the composition in a solvent together with additives such as an antioxidant, a lubricant, an antifoaming agent, a thickener, and a pigment. The curable polymer coating formed on the polyester film may be a single layer or a multilayer.

It may also be a blend of two or more types of curable polymers. The layers of the polymer coating may be the same on both sides or may be of different types. The thickness of the polymer layer is not particularly limited, but is preferably in the range of 0.01μ to 10μ. If it is less than 0.01μ, a continuous film will not be formed, and the generation of oligomers cannot be prevented, which is not preferable.

Moreover, if the thickness exceeds 10 μm, the flexibility of the polyester film may be lost or cracks may appear on the surface, which is not preferable. Generally known methods are used to form the curable polymer layer.

For example, depending on its shape and properties, it can be coated on a polyester film by a coating method using a known coating machine such as a doctor knife, percoater, gravure roll coater, curtain coater, knife coater, spinner, etc., a spray method, or a dipping method. applied. The applied curable polymer layer needs to be dried and cured, but these steps may be performed before, simultaneously with, or after the formation of the transparent conductive film. When this step is carried out by thermosetting, it is necessary to cure at a temperature below the heat resistance temperature of the polyester film and the curable polymer. As long as the temperature is below this temperature, if the polymer layer is applied to both sides of the polyester film, the curing time can be long enough, but if it is applied to only one side,
It is preferable to shorten the curing time or lower the curing temperature to prevent the formation of oligomers in the polyester film. Examples of transparent and conductive layers formed on the curable polymer layer include thin films of metals such as gold, silver, palladium, and aluminum, copper iodide, indium oxide, tin oxide, titanium oxide, and cadmium oxide. Examples include a thin film of a metal compound whose main component is, or a laminated thin film made of a combination of two or more of these.

Further, any figure or letter L may be formed. Means for forming these thin films include methods of evaporating the substance in a vacuum such as vacuum evaporation, ion blasting, and sputtering, vapor phase plating, chemical plating, electroplating, coating, plasma spraying, or a combination of these methods. and so on. Among these methods, the uniformity of the formed film,
From the viewpoint of ease of production, the most excellent method is to evaporate the substance in vacuum. After forming this layer, further physical, chemical, or mechanical treatments may be performed. There is no particular limit to the thickness of the transparent and conductive thin film, but if the thin film is made of metal, it is preferably in the range of several tens to hundreds of layers, particularly 500 Å or less in terms of transparency, and 500 Å or less in terms of conductivity. 40A or more is preferable. If the thin film is made of a transparent and conductive metal compound, there is no upper limit, but if it is too thick, the flexibility of the polyester film will be impaired.
It is preferably 10μ or less, particularly 1μ or more. Moreover, if it is less than 40 A, a continuous film will not be formed and it will not have conductivity, which is not preferable. As described above, the conductive laminated film of the present invention uses a polyester film with a layer of cured or crosslinked curable polymer formed on both sides, and therefore is formed by crosslinking the layer of curable polymer. The network structure prevents the generation of oligomers etc. from the polyester film, so it does not generate low molecular substances, especially oligomers, even at high temperatures, so it can be used even under temperature conditions where it would not be possible to use it due to the generation of oligomers.

Transparent conductive laminated films include those that utilize the interaction between light and electric fields, such as solid-state light emitting devices, photoelectric conversion devices, facsimile recording media, EL displays, and liquid crystal displays: slide films, microfilms, etc. Used as a substrate for electrophotography. It is also used as a base material for windshields of automobiles, airplanes, and other vehicles, traffic lights, heating elements for preventing dew condensation and freezing, thermoplastic recording, photochromic memory, amorphous semiconductor memory, etc. Furthermore, it goes without saying that it can be used for antistatic purposes in meter windows, cathode ray tubes, work mats, etc., for quick starts in fluorescent lamps, and as selective light transmission films. Since the conductive laminated film of the present invention has curable polymer layers on both sides of the polyester film, it has excellent air permeability, moisture permeability, scratch resistance, etc. The present invention will be explained below with reference to Examples.

Example 1 A silica sol solution of an alcoholic solvent containing ethyl silicate as a main component (manufactured by Nippon Colcoat Chemical Co., Ltd., HAS-2) was applied to both sides of biaxially stretched polyethylene terephthalate with a thickness of 75 μm.
) was applied using a gravure coater and cured at 180°C for 5 minutes.

The resulting organopolysiloxane layer had a thickness of about 1000A. Using this film as a base material, thin films of gold, silver, palladium, and aluminum were vacuum-deposited on one side of the film to prepare a conductive laminated film. The properties of the obtained film are shown in Table 1. These films were heated to 170℃,
Although it was heat-treated for one turn, no oligomer was generated at all.

In addition, these films were heated with electricity to 15Watt nod.
However, no oligomer was generated at all.

Furthermore, on these conductive laminated films, a thermosetting acrylic resin in which an electroluminescent material mainly composed of ZnS was dispersed was coated to a thickness of 40 μm and baked at 150°C for 1 hour, but no oligomers were generated. I didn't. On top of this layer,
A thermosetting acrylic resin in which barium titanate was dispersed was applied to a thickness of 20 μm and cured by baking at 170° C., but no oligomers were generated at all. This film could be further laminated with an aluminum electrode and used as an EL light emitting device. Example 2 A 5% normal hexane solution of tetrabutyl tanate was applied to both sides of a 75μ thick biaxially stretched polyester film using a percoater, and then heated at 120°C.
It was heat cured for 5 minutes at a temperature of .

This titanium oxide polymer layer had a thickness of 180A.
Using this film as a base material, a metal thin film layer of gold, silver, palladium, and aluminum was formed by vacuum evaporation method in exactly the same manner as in Example 1, and heat treatment and heating experiments were performed, but no oligomers were generated. . Furthermore, a transparent conductive film containing indium oxide as a main component was formed to a thickness of 1200 Å on the film, which had polymer layers of titanium oxide formed on both sides.

Even when this conductive laminated film was exposed to a temperature of 180° C. for 24 hours under biaxial tension, no oligomers were generated. Example 3 On the polyester film on which the thermosetting polymer layer of Example 1 and Example 2 had been formed, a film mainly composed of a low oxide of indium metal was formed to a thickness of 350 Å by vacuum deposition.

This film was heat-treated at 180° C. for 1 hour under biaxial tension to obtain a conductive laminated film having a surface resistance of 400Ω and an Icltl transmittance of 89%. A conductive laminated film was produced using the same method using a polyester film as a base material, but the resulting film was cloudy due to the generation of oligomers. Furthermore, the adhesion to the transparent conductive coating was also extremely poor. Moreover, even when the former conductive laminated film was subjected to the same heat treatment and electrical heating as in Example 1, no oligomer was generated at all. Comparative Example 1 A thin film of gold, silver, and aluminum was formed on a biaxially stretched polyester film having a thickness of 75p in the same manner as in Example 1 to obtain a conductive laminated film.

When this conductive laminated film was left at a temperature of 170° C. for 1 hour, oligomers were generated and the transparency was significantly impaired. Furthermore, an EL light emitting device was formed using this conductive laminated film as a base material in the same manner as in Example 1, but oligomers were generated during baking hardening of the thermosetting acrylic resin.

[Brief explanation of the drawing]

Figure 1 shows a film with transparent conductivity on only one side, and Figure 2 shows a film with transparent conductivity on both sides.

Claims (1)

[Claims] 1. A conductive laminated film in which a transparent conductive layer 2 is formed on at least one side of a polyester film,
A conductive laminated film characterized in that the layer 2 is formed through at least one layer 1 of a curable polymer layer 1 formed and cured on both sides of a polyester film. 2. The conductive laminate film according to claim 1, wherein the curable polymer is a polymer composed of an organometallic compound containing metal atoms.