JPH04187758A - Production of transparent conductive-surface polymeric film - Google Patents

Abstract

PURPOSE:To easily obtain a conductive-surface polymeric film having excellent conductivity and transparency by converting the metal layer formed on the polymeric film surface into a sulfide layer. CONSTITUTION:A metal is deposited on the surface of a polymeric film to form a thin-film layer excellent in adhesion, which is then treated with gaseous hydrogen sulfide. Consequently, the metal is converted into its sulfide without the adhesion and homogeneity being damaged, and a polymeric film having excellent transparency and surface conductivity is obtained. Since the thickness of the deposited metal is freely controlled by this method, the resistance of the sulfide thin film layer is freely changed, and a conductive-surface polymeric film having desired performance is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to an improvement in a method for producing a transparent surface-conductive polymer film. More specifically, the present invention is applicable to, for example, antistatic equipment, electronic materials, electromagnetic shielding materials,
The present invention relates to a method for manufacturing a transparent surface conductive polymer film having a transparent and conductive metal sulfide layer, which is useful as a polymer electrode.

Background of the Invention In recent years, conductive polymer films have attracted attention as new functional materials, as they can be used for antistatic equipment, electronic materials, electromagnetic shielding materials, polymer electrodes, etc.
In particular, transparent surface-conductive polymer films are endowed with conductivity without sacrificing the inherent desirable properties of polymer films, such as being lightweight, inexpensive, and having excellent formability and stability. It is widely used as a flexible transparent conductive film in LCO electrodes, touch spring solar cells, etc.

Examples of such transparent surface-conductive polymer films include those in which indium oxide (hereinafter abbreviated as ITO) is deposited on the surface of a polymer film to form a conductive thin film layer, and ultra-fine conductive films on polycarbonate films. Some are known in which metal wires are semi-embedded, and others in which copper sulfide is deposited on the surface of a polymer film to form a conductive thin film layer.

The above-mentioned polymer film with ITO deposited on its surface is a typical transparent surface conductive polymer film, and many types have been known so far, such as LCO electrodes and solar cell electrodes. It is widely used. By the way, in a surface conductive polymer film in which a metal is deposited on the surface of the polymer film, in order to impart transparency, it is necessary to reduce the thickness of the metal thin film. It is inevitable that performance will deteriorate. Although the ITO deposited surface conductive polymer film has excellent transparency, it has drawbacks such as a surface resistance of about 100 Ω/'day, poor conductivity, and expensive metal indium. ing.

Furthermore, a polycarbonate film in which ultrafine metal wires are semi-embedded has transparency and is used for electrodes in touch panels, etc., but there is a limit to improving resolution.

On the other hand, in polymer films with copper sulfide deposited on the surface, the copper sulfide is stable and is an excellent conductor with a conductivity that is one to two orders of magnitude lower than that of metal steel, and is also transparent. Therefore, it is preferable.

To deposit copper sulfide on the surface of a polymer membrane, the polymer membrane is usually immersed in a mixed aqueous solution of a copper compound and a reducing sulfur compound and heated to generate copper sulfide. However, although such a wet method yields a polymer film with relatively good surface conductivity, the copper sulfide thin film layer formed is thin and the surface resistance is about 5Ω/mouth. is the limit, and it has been difficult to further improve the conductivity. Further, when metal sulfides are deposited on the surface of a polymer film by such a wet method, there arises a problem that the metal sulfides that can be deposited with good adhesion to the surface of the polymer of the base material are limited.

On the other hand, it is easily possible to deposit metal on the surface of a polymer film using known methods, but depending on its thickness, the resulting metal thin film layer may have excellent conductivity but poor transparency, or vice versa. Even if the film has excellent transparency, the conductivity may be insufficient, making it difficult to obtain a fully satisfactory transparent surface conductive polymer film.

Problems to be Solved by the Invention The present invention has been made with the object of providing a surface conductive polymer film having good conductivity and transparency by a simple method.

Means to Solve the Problem The inventors of the present invention have conducted intensive research to develop a transparent surface-conductive polymer film with desirable properties.The inventors first deposited a metal on the surface of the polymer film to improve its adhesion. After forming a homogeneous thin film layer with excellent transparency, by treating it with hydrogen sulfide gas, the metal is converted to sulfide without damaging the adhesion or homogeneity of the thin film layer, resulting in excellent transparency. It was discovered that a polymer film having surface conductivity could be obtained, and the present invention was completed based on this knowledge.

That is, the present invention provides a transparent surface-conductive polymer characterized in that a metal layer is formed on the surface of a polymer membrane, and then this is treated with hydrogen sulfide gas to convert the metal layer into a sulfide layer. A method for manufacturing a membrane is provided.

The present invention will be explained in detail below.

There are no particular restrictions on the material of the polymer membrane used in the method of the present invention, and any material can be selected from those conventionally used for surface conductive polymer membranes. Further, the thickness of the polymer membrane is usually 5 to 500 μm.
selected within the range of m.

In the method of the present invention, it is desirable to activate the surface of the polymer film by subjecting it to plasma etching treatment or sputter etching treatment using plasma in advance before forming the metal layer on the surface of the polymer film. This treatment further improves the adhesion of the formed thin film layer. In particular, it is advantageous to carry out a sputter etching treatment using plasma.

This plasma treatment method is not particularly limited, and methods conventionally used for plastic surface treatment, such as high frequency plasma treatment and microwave plasma treatment, can be used, but high frequency plasma treatment is particularly preferred.

As the high-frequency plasma device, a parallel plate type device is preferable, and its output direction, reaction pressure, and reaction time vary depending on the device conditions, such as electrode area, distance between electrodes, exhaust capacity, etc., and cannot be determined generally. , the polymer base material is placed in an inert gas atmosphere such as argon, and 1
Under a pressure of about 0 to 100 mm Torr, the output too
The sputter etching process is performed by generating plasma using a high frequency of -1000 W and a frequency of about 10 to 100 MHz. There is no particular restriction on the treatment time, but about 10 to 60 minutes is sufficient.

Next, a desired metal layer is formed by depositing a metal, for example, on the surface of the polymer film whose surface has been activated by sputter etching using plasma. Any metal can be used as long as it can react with hydrogen and convert into a transparent and conductive sulfide, and metals such as copper, silver, zinc, iron, nickel, cobalt, and cadmium are suitable, although there are no particular limitations. Of course, metals other than these can also be selected as appropriate depending on the purpose.

There are no particular limitations on the method of forming these metal layers on the surface of the polymer film, and known methods such as vacuum evaporation and sputtering can be used.

In the present invention, a thin film layer made of a homogeneous metal with excellent adhesion is thus formed on the surface of the polymer membrane, and then treated with hydrogen sulfide gas to convert the metal into sulfide. .

There is no limit to the concentration of the hydrogen sulfide gas used in this treatment, but from the viewpoint of ease of handling, it is preferable to dilute it with an inert gas such as nitrogen or argon. About 10% by volume is used.

Regarding the processing temperature, the upper limit depends on the heat resistance temperature of the base polymer, but it is usually selected in the range of room temperature to 150°C, and the processing time depends on the processing temperature.
Although it cannot be determined generally, several tens of minutes to several hours is usually sufficient. Further, although there are no particular restrictions on the pressure, the treatment is usually performed under atmospheric pressure.

In this way, the metal layer is converted to sulfide, and a polymer film with excellent surface conductivity and transparency is obtained.

Effects of the Invention According to the method of the present invention, a homogeneous metal layer with excellent adhesion is first formed on the surface of a polymer film, and then a hydrogen sulfide gas treatment is performed in the gas phase to convert it into a thin film layer made of sulfide. By doing so, it is possible to easily obtain a surface conductive polymer film having a homogeneous thin film layer with excellent surface conductivity and transparency, and good adhesion.

In addition, according to the method of the present invention, the thickness of the thin film layer made of deposited metal can be freely controlled, so the resistance of the thin film layer made of sulfide obtained can be freely changed, and the performance can be adjusted according to the purpose. A surface conductive polymer film can be provided.

The transparent surface conductive polymer film obtained by the method of the present invention can be used, for example, in antistatic equipment, electronic materials, electromagnetic shielding materials, etc.
Suitable for use in polymer electrodes, etc.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 A polyethylene terephthalate film with a film thickness of about 50 μm was heated at a pressure of 20 m in an argon gas atmosphere using a high-frequency plasma device with an electrode area of 50 cm and a distance between the electrodes of 8 cm.
High frequency plasma sputter etching treatment was performed for 20 minutes under the conditions of Torr, output of 600 W, and frequency of 13.56 MHz. The appearance of the t=pretreated film thus obtained was almost the same as the original film.

Next, the T-pretreated film obtained in this way was set on the substrate side of an ordinary high-frequency sputtering device, using pure metallic copper as the target and argon as the sputtering gas, and the reaction conditions were pressure and pressure. Q, 1 Torr, output 20
It was set to 0W. When sputtering was performed for 2.5 minutes with argon flowing at 5 mQ/min, metallic copper was deposited on the surface of the polyethylene terephthalate film to a thickness of about 0.0 mm.
A homogeneous thin film layer of 8 μm was formed. This thin film layer had excellent adhesion and did not peel off even in a scorch tape peel test. Hereinafter, this film will be referred to as a copper deposited film.

Next, this copper deposited film was placed in a flask, and after purging with 10% by volume hydrogen sulfide gas diluted with nitrogen, the flask was immersed in an oil bath and treated at 150° C. for 1 hour. After the reaction was completed, the film turned transparent green.

xPS of the thin film on the film surface treated in this way
Analysis revealed that the main component was divalent copper sulfide. In addition, the surface resistance of this film is approximately 20/
The visible light transmittance is approximately 20% in the 550 nm region.
Met. By the way, visible light did not pass through the copper deposited film at all.

Comparative Example 1 When the copper deposited film obtained in Example 1 was immersed in an aqueous solution of polyammonium sulfide, which is a reducible sulfur compound, only the metal surface became black and no change to copper sulfide was observed.

Example 2 The experiment was carried out in the same manner as in Example 1, except that the hydrogen sulfide gas treatment time was changed to 6 hours.

The surface resistance of the obtained film was about 1Ω/mouth, and xPS analysis revealed that the main component of the formed thin film was divalent copper sulfide.

Comparative Example 2 When the copper deposited film obtained in Example 1 was immersed in a 0.1 mol/Q aqueous solution of sodium thiosulfate, which is a reducing sulfur compound, and heated to 80°C, the same result as in Comparative Example 1 was obtained. , the film turned black and the thin film formed on the film peeled off easily.

Example 3 A test was carried out in the same manner as in Example 1 except that pure nickel was used as the metal. The obtained nickel sulfide thin film layer was dark yellow and transparent, and as a result of xPS analysis, it had a composition close to Ni52.

The surface resistance of this film was 350Ω/hole, and the light transmittance was about 10% in the 600 nm region.

Comparative Example 3 In Example 3, when a polyammonium sulfide aqueous solution was used instead of hydrogen sulfide gas, the surface only became black and no conversion to 2.7K sulfide was observed.

Claims (1)

[Scope of Claims] 1. A transparent surface conductive high film characterized by forming a metal layer on the surface of a polymer film, and then treating this with hydrogen sulfide gas to convert the metal layer into a sulfide layer. Method for manufacturing molecular membranes. 2. The method for producing a transparent surface-conductive polymer film according to claim 1, wherein the surface of the polymer film used is activated by sputter etching.