JPS6135268B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a molded product having transparent conductivity, and more specifically, the present invention relates to a method for producing a molded product having transparent conductivity, and more specifically, a coating film of a metal or low metal oxide on the molded product is coated in a normal pressure gas phase containing oxygen. The present invention relates to a method for producing a molded product having a transparent conductive film by contacting with an oxygen atmosphere activated by a discharge reaction to oxidize the product.

Conventionally, methods for oxidizing metal or low metal oxide coatings include, for example, heating oxidation in a gas phase, liquid phase oxidation using an oxidizing agent, glow discharge oxidation, or arc discharge oxidation.

Among these oxidation methods, the thermal oxidation method is effective when using a molded polymer as a substrate. It has been difficult to form a transparent conductive film of metal oxide on a substrate without impairing its flatness. In addition, liquid phase oxidation using an oxidizing agent and anodic oxidation can oxidize at room temperature, and a transparent conductive film made of metal oxide can be formed even on the surface of a polymer molded product with low heat resistance.
On the other hand, it has been difficult to prevent part of the metal coating from eluting into the solution. Glow discharge oxidation requires special vacuum equipment and is not necessarily an industrially advantageous method, and arc discharge oxidation is carried out at very high temperatures (3000-6000).

The inventors of the present invention have discovered that the above-mentioned coating film can be easily oxidized, that a molded product with low heat resistance can be used as a substrate, and that the oxide film is uniform.
As a result of intensive research on oxidation methods for electrokinetic coatings, we have found that a method of oxidation using an atmosphere activated by silent discharge or corona discharge in a normal pressure gas phase containing oxygen satisfies the above requirements. heading,
This has led to the present invention.

That is, the present invention provides a method for producing a molded product having a transparent conductive film by oxidizing a metal or metal low oxide coating film coated on the surface of the molded product, in which the oxidation is carried out in an atmospheric pressure gas phase containing oxygen. This is a method for producing a molded article having a transparent conductive film, characterized in that the process is carried out by bringing the coating film into contact with an oxygen atmosphere activated by an electric discharge therein.

As the molded product base material used in the present invention, any of organic polymer molded products, inorganic molded products, and composite molded products thereof can be used.

Examples of organic polymer molded products include polyethylene terephthalate resin, polyethylene naphthalate resin, acrylic resin, ABS resin, styrene resin, polyacetal resin, polyethylene resin,
Thermoplastic resins such as polypropylene resins, epoxy resins, diallyl phthalate resins, silicone resins,
Examples include thermosetting resins such as unsaturated polyester resins, phenolic resins, and urea resins. Moreover, these may be used alone or in a mixture of two or more.

Examples of the inorganic molded product include glass materials such as soda glass, borosilicate glass, and silicate glass, ceramics such as alumina, magnesia, zirconia, and silica, as well as metal oxides and various compound semiconductors.

Polymer molded products are lighter than inorganic molded products, and have excellent processability such as punching and cutting, flexibility, impact resistance, and dielectric properties. The shape of this molded product can be arbitrary, and examples include a sheet shape and a film shape, but a film shape has the advantage that it can be rolled up and produced continuously. Among these, polyethylene terephthalate film is particularly excellent in heat resistance, transparency, and electrical properties. In order to take full advantage of these excellent properties, the film thickness is preferably 6 to 500 μm, particularly preferably 12 μm.
~125μ.

The coating films on the surfaces of these substrates are formed from metals or metal-reducing oxides. Examples of metals include tin, indium, titanium, and zirconium, which may be used singly or in combination of two or more types, and as metal low oxides, one or more of these metals may be used. can give. Among these, from the viewpoint of transparency, conductivity, and ease of oxidation treatment of the coating film, low oxide of indium (In _x O _y (however, 0.5<Y/X<1.5)] or low oxide of indium/tin is recommended. In _x Sn _z O _y (however, the relationship between x and y is the same as above, and z is z>O) is particularly preferable.

Methods for providing the metals and low oxides of metals on the molded substrate include vacuum evaporation, cathode sputtering, plasma spraying, vapor phase plating, chemical plating, electroplating, and chemical coating. Although any method or a combination thereof is possible, vacuum evaporation method and cathode sputtering method are particularly suitable from the viewpoint of uniformity of the formed coating film, ease of manufacture, and ability to coat nonconductor molded objects. . At this time, the coating thickness of the metal or metal oxide mentioned above is determined in relation to the conductivity and translucency of the transparent conductive film, the time required for oxidation treatment, etc., and is not uniform, but the upper limit is the coating thickness. From the standpoint of adhesion and uniformity between the layer and the base material of the molded product, it is approximately 3000 Å, and from the viewpoint of ease of oxidation it is less than 2000 Å, and from the viewpoint of the transparency of the resulting film.
The thickness is preferably 1500 Å or less. On the other hand, the lower limit of the film thickness cannot be determined uniquely depending on the use of the resulting transparent conductive film, but for example, 30 Å is sufficient for preventing static electricity.

In the method of the present invention, an oxygen atmosphere is activated by a discharge reaction in a normal pressure gas phase containing oxygen, and the above-mentioned coating (on the molded product) is oxidized by contact with this atmosphere. However, this discharge is silent discharge and corona discharge. This 2
Seed type discharges, unlike other types of discharges such as glow discharges and arc discharges, are self-sustaining discharges before sparking due to partial breakdown. In addition, other types of discharge and corona discharge do not require low pressure (around 1 Torr) like glow discharge, and do not require high temperatures (3000 to 6000〓) like arc discharge, and can be used at room temperature. It is characterized by being carried out near normal pressure. Therefore, the discharge in the method of the present invention does not require a special vacuum device such as a glow discharge, and the structure of the device is not complicated, and there is an advantage that a large area of coating can be easily and continuously treated.

In general, the distinction between silent discharge and corona discharge is not necessarily clear, but silent discharge is caused by the induction between two electrodes.
This refers to the discharge phenomenon that occurs in the gap when a high voltage is applied to a light stream through an electric body, and the ozone generation efficiency is superior to that of ordinary corona discharge, making it particularly suitable for the method of the present invention. Active chemical species such as ozone are generated by performing silent discharge or corona discharge in a normal pressure gas phase containing oxygen. When an atmosphere containing this active chemical species comes into contact with a molded product coated with a film of, for example, indium metal or its low oxide, an oxidation reaction of the coating film proceeds rapidly, resulting in a molded product with a homogeneous transparent conductive film. Things can be manufactured easily.

Since the oxidation method in the method of the present invention can be carried out at a temperature around room temperature, a polymer having relatively low heat resistance can be used as the base material of the molded product. Furthermore, in the method of the present invention, the molded product and/or the activated oxygen atmosphere may be appropriately heated, thereby shortening the oxidation time. The preferred range of this heating temperature varies depending on the heat resistance of the molded product base material and is not uniform.
For example, when the base material is polyethylene terephthalate, the temperature is preferably 200°C or less.

When performing discharge oxidation in the method of the present invention, if the coating film is oxidized near the discharge electrode, the layer near the top of the film where oxidation has progressed excessively and the conductivity has significantly decreased may be removed by etching. can. By this etching, a transparent conductive film having good conductivity can be obtained. Note that the gap in the vicinity of the electrode varies depending on the shape of the electrode and the applied voltage. For example, when the applied voltage is several KV, the distance is within 5 cm from the electrode, and when the applied voltage is around 20 KV, the distance is within 5 cm from the electrode.
Preferably within 15cm.

According to the method of the present invention, it is possible to continuously produce a molded product having a uniform conductive film, and the obtained products can be used, for example, in electrophotography, antistatic materials, surface light emitters, etc.
It has a wide range of uses, including solid-state displays, optical memories, photoelectric conversion elements, optical communications and information processing, and solar energy utilization materials.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts in the examples are parts by weight.

Example 1 A mixture of 93 parts of indium oxide and 7 parts of tin oxide was vacuum-deposited onto a polyethylene terephthalate film having a thickness of 75 μm. The obtained vapor deposited film is indium.
Low oxide of tin, film thickness 250 Å, surface resistance 60
It is a black conductive film with a transmittance of 50% for light at KΩ/□ and 600 nm. Oxygen gas was activated using an ozone generator type 0-1-2 (manufactured by Nippon Ozone Co., Ltd.) at 160°C (ozone concentration in oxygen gas: 1.6% by weight).
When the film was flowed for 30 minutes over the black conductive film that had been heated to 300 nm, a transparent conductive film with a surface resistance of 5 KΩ/□ and a transmittance of 600 nm light of 86% was obtained. On the other hand, when the same amount of oxygen gas without any activation was flowed for 30 minutes over a similar black conductive film heated to 160℃, the resulting transparent conductive film had a surface resistance of 12KΩ/□. , the light transmittance at 600 nm was 71%, and the transparency was considerably poorer than that in the case where oxygen gas was not activated.

Example 2 A mixture of 92 parts of indium oxide and 8 parts of tin oxide was vacuum-deposited onto a polyethylene terephthalate film having a thickness of 75 μm. The obtained vapor deposited film is a black conductive film made of a low oxide of indium and tin, having a thickness of 300 Å, a surface resistance of 50 KΩ/□, and a transmittance of 600 nm light of 45%.

The film was placed on a roller-shaped corona discharge electrode heated to 150° C., and corona discharge was performed for 40 minutes by applying 10 KV to oxidize the indium low oxide layer and simultaneously remove the top layer.

The obtained film has a light transmittance of 86% (600n
m) The surface resistance was 75KΩ/□, and the thickness of the oxide layer was 220Å.

Example 3 When a vapor-deposited film similar to that used in Example 2 heated to 150°C was brought into contact with an active atmosphere 10 cm away from a corona discharge electrode to which 10 KV was applied for 45 minutes, the surface had a light transmittance of 85% (600 nm). resistance is 100K
A film of Ω/□ was obtained. The thickness of the oxide layer is
It was 300Å.

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Claims (1)

[Claims] 1. When producing a molded product having a transparent conductive film of a metal or metal low oxide coated on the surface of the molded product, the oxidation can be carried out by silent discharge in a normal pressure gas phase containing oxygen or A method for producing a molded article having a transparent conductive film, characterized in that the method is carried out by bringing the coating film into contact with an oxygen atmosphere activated by corona discharge. 2. The coating film is a film formed from one or more metals and/or low oxides of metals selected from the group consisting of tin, indium, titanium, zirconium metals, and low oxides of these metals. A method for producing a molded article having a transparent conductive film according to claim 1. 3. The method for producing a molded article having a transparent conductive film according to claim 1, wherein the transparent conductive film is indium oxide or a film of indium oxide and tin oxide.