JPH0877833A - Plastic forming body and its manufacture - Google Patents

Abstract

PURPOSE: To improve antistatic and electromagnetic shielding effects by forming a transparent conductive film consisting of Zn0 film. to which Ga is added, on the surface of a plastic base body. CONSTITUTION: A target 5 formed by a sintering body of ZnO to which Ga of 0.5 to 20mol.% is added to the sum of the metal atoms of Ga and Zn and a plastic base body 4 are arranged in a vacuum tank 1 opposed to each other. After inert gas is introduced from a gas introduction port 2 into the vacuum tank 1, DC voltage is applied from a DC power supply 6 to the target 5 so that a transparent conductive film is formed on the base body 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molded product having a film or sheet-like plastic surface coated with a transparent conductive film to impart effects such as antistatic property and electromagnetic shielding, and a method for producing the same.

[0002]

2. Description of the Related Art Up to now, various methods have been proposed or put into practical use as a method for imparting conductivity to a plastic molding for the purpose of preventing static electricity. For example, a method of mixing a conductive material such as metal or carbon with the plastic itself, a method of adhering it by a wet process, or a method of coating the surface of the plastic with a conductive substance by a dry process such as in vacuum. To be

In a method of mixing a filler of a conductive substance such as metal or carbon with plastic and molding it into a film or sheet, transparency is often lost.
There are restrictions on the properties of the resulting plastic, making it difficult to use except for special purposes.

Further, in the wet treatment, steps such as drying are essential and the number of steps is large and a large amount of water is required.
There are problems such as large variations in thickness and characteristics of the film to be formed.

On the other hand, the dry process is considered to be a method capable of solving these problems, and many reports have been made to date. A method of coating a metal film on the surface of plastic by a method such as vapor deposition has already been put into practical use, but the plastic obtained by this method can only obtain a metallic tone and loses transparency. A method (Japanese Patent Publication No. 60-45586) of controlling the thickness of a metal film to be coated to a thin film thickness of 25 nm or less so as to ensure a sufficient light transmittance has been proposed, but such an ultrathin film has scratch resistance, There is concern about the problem of durability due to corrosion such as oxidation.

As a method that does not impair the color tone of the underlying layer, a method of coating a transparent conductive oxide film of In, Sn or the like is known. These are processes in which a metal is used as a target when forming by sputtering or the like, oxygen is used as a gas for sputtering, and a reaction is utilized, but in this case, it is difficult to control the reaction, and the optical and electrical properties depend on the degree of oxidation. It is easy to change the nature further,
There is a problem that the forming speed is very low.

Recently, a method of forming a transparent conductive film using an oxide target such as ITO has been known.
1) The crystallinity of the formed film is poor and good conductivity cannot be obtained at a low temperature that does not deteriorate the plastic of the substrate. 2)
Since the mechanical strength of the target is low, the limit of input power is low. 3) Since it is necessary to introduce a small amount of oxygen gas, it is difficult to control, and oxygen plasma damages the plastic substrate, etc. There's a problem.

As a method of improving this point, a facing target type magnetron sputtering has been proposed (JP-A-5-307914).

However, this method has a problem that the apparatus becomes complicated and lacks versatility. That is, an industrial production method of a transparent conductive film-coated plastic molded product by a dry method, which is excellent in productivity and processing cost, has not been established.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transparent conductive film-covered plastic molded product which can be industrially produced and which has good conductivity even at a low temperature without deteriorating the plastic of the substrate. Another object of the present invention is to provide a transparent conductive film-coated plastic molded product that can be formed without the need for oxygen gas.

[0011]

The present invention provides a plastic molded article in which a transparent conductive film is coated on the surface of a plastic substrate, wherein the transparent conductive film is ZnO to which Ga is added.
Provided is a plastic molding characterized by being a film and a method for producing the same.

In the conventional ITO film or the like, it is necessary to heat the substrate in order to obtain a good quality film, but the transparent conductive film of the present invention can produce a good quality transparent conductive film having high crystallinity even at room temperature. The device can be simplified and damage to the plastic of the substrate due to heating can be avoided.

The film formation rate is sufficiently higher than that of the oxidation reaction sputtering of a metal target as well as the sputtering of an oxide target such as ITO. Since the target is conductive, direct current sputtering can be performed and coating on a large substrate is possible. It is possible, and if the substrate is a film with a thickness of 300 μm or less, it can be applied to a roll-to-roll system having a width of 3 m or more, and a great improvement in productivity can be expected.

The transparent conductive film of the present invention can be formed in an oxygen-free atmosphere. For example, a target film can be formed by sputtering a Ga-added ZnO oxide target only with an inert gas. Therefore, since there is no reaction gas such as oxygen gas, there is no problem of reaction control, and stable film formation with various characteristics can be achieved. In addition, there is an advantage that damage such as discoloration and deterioration of the plastic of the substrate due to the oxygen gas turned into plasma can be suppressed.

As a method for forming the transparent conductive film on the plastic molded body, various coating methods can be selected. In order to fully exert the function provided by the present invention,
It is preferable to use a sputtering method by using a ZnO sintered body to which Ga is added as a target. This is because the adhesion of the transparent conductive film to the plastic surface is higher than that of other forming methods such as vacuum deposition.

The Ga-doped ZnO film of the present invention not only exhibits equivalent performance in terms of conductivity, transmittance, etc. as compared with the conventionally known ITO film, but also changes the Ga addition amount. Can control the conductivity.

From the viewpoint of conductivity and internal stress of the film, the content ratio of Ga in the transparent conductive film is preferably 0.5 atom% or more and 20 atom% or less with respect to the total of metal atoms of Ga and Zn.

As described above, it is possible to avoid damage to the plastic of the substrate due to the reaction gas, heating of the substrate, etc.
As the base plastic, polyvinyl chloride, polyethylene, polystyrene, polypropylene, polyester, polycarbonate, polyethylene terephthalate,
Various general-purpose plastics such as polyamide and acrylic resin, and various plastics such as fluorine series and silicone series are applicable.

In addition, sufficient adhesion can be obtained without any pretreatment for improving adhesion to plastic. Therefore, when etching is performed in the next step, since the base film is unnecessary in the plastic molded body of the present invention,
High etching rate and good productivity.

Since the Ga-doped ZnO film coated on the plastic molded body of the present invention is a conductive film, it has a shielding effect against light, heat and electromagnetic waves and an antistatic effect, and is a ceramic film. , Scratch resistance, heat resistance, corrosion resistance, weather resistance, and airtightness can be expected. That is, it is possible to add characteristics that the base plastic does not have. Further, since it is transparent, the transparency of the plastic of the base material is not lost, or the design of the dye, pattern, etc. applied to the plastic, or the color of the plastic itself can be utilized. Therefore, wide applications such as the following a) to h) are possible.

A) various transparent plastic sheets and films that utilize antistatic properties to prevent generation of static electricity and adhesion of dirt, b) various plastic substrates for electronic devices on which transparent electrodes are formed, and c) flexible transparent surface Heater, d) Cover film for anti-dirt and anti-static of interior wall material, floor material, and ceiling material, e) Inner wall for preventing malfunction of electronic products such as computers using electromagnetic shielding property, window material and electronic product packaging material, f ) Interior materials for automobiles, etc. that utilize non-combustibility, flame retardancy, heat resistance, g) Agricultural and outdoor house materials with heat ray reflection and UV blocking effects, h) Decorations that have an iris color that utilizes light interference effects Film.

Since the transparent conductive film-coated plastic molded product of the present invention can obtain a transparent conductive film having stable characteristics at a sufficient formation rate by sputtering an oxide target, it is possible to shorten the process, reduce the production cost, etc. Improvement of industrial productivity can be expected.

[0023]

EXAMPLE FIG. 1 shows an example of a sputtering apparatus used for producing the transparent conductive film-coated plastic of the present invention. In FIG. 1, the vacuum chamber 1 is provided with a gas inlet 2 for introducing gas into the vacuum chamber and an exhaust port 3 for exhausting gas from the vacuum chamber. A DC power supply 6 is connected to the target 5 and is insulated from the vacuum chamber 1. The plastic substrate 4 on which the coating is formed is movable so as to face the target 5. Various methods can be used for installing the plastic substrate 4 depending on its shape. In the case of a film, a roll-to-roll method is also possible, which is particularly effective in a mass production machine.

In the following examples, Examples 1 to 3 are Examples and Example 4
6 are comparative examples.

[0025] [Example 1-3] to the vacuum chamber of the sputtering apparatus described in FIG. 1, the plastic substrate 4 made of a polyester (thickness 0.1 mm) was set so as to face the target 5, 1 × 10 ^-5 Exhausted to Torr. As targets, various targets shown in Table 1 were used. The target addition amount of Ga shown in the table is Ga
And Zn are the amounts with respect to the total of metal atoms. Next, argon gas was introduced through the gas inlet 2 under the conditions shown in Table 1,
A target 5 having a diameter of 6 inches was subjected to DC magnetron sputtering to obtain about 100 on the plastic substrate 4 at room temperature.
nm transparent conductive film was formed. The composition of the obtained transparent conductive film was almost the same as the composition of the target used. In addition, the amount of O ₂ in the table indicates the volume% of oxygen in the sputtering gas. The results are shown in Table 1.

[Examples 4 to 6] The target used in Example 1 was replaced with Sn, ITO and Al-added ZnO as shown in Table 2, and a film was formed under the conditions of Table 2. IT shown in the table
The addition amount of Sn of the O target is an amount with respect to the total of metal atoms of Sn and In, and the addition amount of Al of the Al-added ZnO target is an amount with respect to the total of metal atoms of Al and Zn. In addition, in Example 4 and Example 5, when the film was directly formed on the plastic substrate, film peeling occurred. Therefore, SiO ₂ was formed to a thickness of 20 nm as a base film. Table 2 shows the results.

In Example 4, the resistance was high, the film formation rate was slow, the substrate was damaged, etc. In Example 5, the film formation rate was low, and the oxygen partial pressure control was required. In Example 6, the resistance was high. It was confirmed that the film formation rate was slow, but in Examples 1 to 3, there was no such problem.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

As described above, according to the present invention, by covering the surface of the plastic molded body with the transparent conductive film of ZnO containing Ga, the transparency, color, design, etc. of the plastic of the substrate can be improved. Antistatic property without damage,
It is possible to add characteristics not found in plastics of the substrate, such as prevention of adhesion of dirt, blocking of light, heat and electromagnetic waves, water repellency, heat resistance, corrosion resistance, weather resistance and airtightness.

Further, in the present invention, since a reaction gas such as oxygen gas is not required and heating of the substrate is not required, the apparatus can be simplified and stable forming conditions desirable for production can be obtained.

Further, since the formation speed thereof is sufficiently high as compared with the existing transparent conductive film, the productivity can be greatly improved. In addition, since the target is conductive, it can be sputtered by a DC power supply and can be used to process large substrates. From the above points, according to the present invention, problems such as the productivity of the prior art of the transparent conductive film-covered plastic molded product and the plastic applicable range can be solved, and industrial production can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an apparatus for carrying out the present invention.

[Explanation of symbols]

 1: Vacuum tank 2: Gas introduction port 3: Gas exhaust port 4: Plastic substrate 5: Target 6: DC power supply

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display H05K 9/00 W

Claims (5)

[Claims] 1. A plastic molded body in which a transparent conductive film is coated on the surface of a plastic substrate, wherein the transparent conductive film is a ZnO film to which Ga is added. 2. The content ratio of Ga in the transparent conductive film is 0.5 atom% with respect to the total of metal atoms of Ga and Zn.
The plastic molded body according to claim 1, wherein the content is 20 atomic% or less. 3. A method for producing a plastic molded body in which a transparent conductive film is coated on the surface of a plastic substrate, wherein the transparent conductive film is a Ga-added ZnO film and is formed in an oxygen-free atmosphere. A method for producing a plastic molded body, comprising: 4. A method for producing a plastic molded body in which a transparent conductive film is coated on the surface of a plastic substrate, wherein the transparent conductive film is formed by a sputtering method using a ZnO sintered body to which Ga is added. A method for producing a plastic molded body, comprising: 5. The content ratio of Ga in the transparent conductive film is 0.5 atom% with respect to the total of metal atoms of Ga and Zn.
It is 12 atomic% or less, and the method for producing a plastic molded body according to claim 3 or 4, wherein