JPS60203432A - Manufacture of transparent conductive film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a transparent conductive film used for transparent polarization for liquid crystals, in which a metal conductive film mainly composed of indium oxide is provided on a polymer.

Conventionally, transparent conductive films are mainly based on polyester films, and are used for transparent electrodes in electroluminescent displays and electrochromic displays, surface heating elements such as defrosters and transparent heaters, surface switches such as touch panels, infrared reflective films, and transparent 7 lexiple circuits. Although it is widely used for plates, etc., its application to liquid crystal display elements is also being considered recently. This is because the device can be made thinner by using a film-like electrode tf, and it is easy to handle in the production process and can be processed by punching.

It has the characteristics of being able to be produced continuously from film-like materials.

The transparent conductive film is made by vacuum deposition method on the sieve molecular film.
It is manufactured by completely forming a conductive film using an ion blasting method or a sputtering method. W oxide containing indium as a main component is often used as the conductive film, but since high transparency is required in addition to high conductivity, the film thickness is often made thin. For this reason, it lacks mechanical strength and also has problems with chemical resistance. In order to prevent wire breakage due to scratches in the transparent conductive film manufacturing process, scratch resistance is required (Note) and cracks caused by the alkaline cyst-removal liquid used to form thin wire circuits can cause wire breakage. Since alkaline performance is required, these measures are necessary.

Conventionally, the two properties of scratch resistance and alkali resistance have been improved by providing an undercoat layer and a topcoat layer. Sufficient performance cannot be obtained with either the undercoat layer or the topcoat layer alone, and it is necessary to perform both. However, this is not preferable because it complicates the manufacturing process and increases costs. Furthermore, regarding the top coat, is it coated on a fragile inorganic thin film? We are facing a technically difficult problem.

As a result of intensive study on this point, the inventors of the present invention found that using a thermosetting resin as an undercoat material, a transparent conductive film was prepared in a low cured state in advance. It has been found that when the transparent conductive film is formed and then reheated, the curing reaction is completed with the transparent conductive film partially or completely embedded in the undercoat. In such a state, the transparent conductive film is embedded and fixed in the undercoat resin, resulting in stable transparent conductivity with excellent processability such as scratch resistance and alkali resistance that could not be obtained with conventional manufacturing methods. It becomes a sexual film. The manufacturing method will be described in detail below.

As the undercoat material, a thermosetting resin that has adhesive properties with the base film is used. In this case, it is preferable to use a material that can be cured not only by heat but also by ultraviolet irradiation, radiation irradiation, etc. This is because the base film is coated and pre-cured, and the process time can be shortened by performing full ultraviolet curing at this stage. The precuring at this stage has two purposes: to facilitate handling in the following work steps, and to avoid gas release in vacuum during formation of the conductive film.

That is, when a plastic substrate is used, the conductive film is formed by vacuum evaporation, ion blasting, or sputtering. These are all physical film forming methods performed in a vacuum, and gas released from the substrate often has a negative effect on film quality. However, if the precuring reaction progresses too much at this stage, the transparent conductive film will not be embedded even if heated after the conductive film is formed, and a transparent conductive film with the desired performance cannot be manufactured. The extent to which pre-curing is carried out varies greatly depending on the reaction rate, glass transition temperature, volatile component ratio, etc. of the undercoat material, and although it cannot be generalized, if the curing reaction rate exceeds 70%, the desired transparency It is not possible to produce a conductive film using any thermosetting resin undercoat material. Furthermore, if the curing reaction rate of the pre-curing is 80% or less, the formation of a transparent conductive film is significantly hindered. It is desirable that the curing reaction rate of the pre-curing is 50 to 70%.

Here, the curing reaction rate is the unreacted monomer detected by solvent extraction, W1, raw material WO, and undercoating materials such as acrylic resin, melamine resin, phenol resin, epoxy resin, etc., and sP4 curing type. Resin can be used. However, the hardness when fully cured is JIS
It must have a pencil hardness of 2H to 5H according to K-5400. If it is less than 2H, the scratch resistance will be poor, and if it is more than 5H, stress will be applied to the conductive film during curing of the undercoat material, resulting in high resistance.

Does the base plastic film have a higher heat resistance than the reaction temperature of the undercoat material? It is necessary to have it.

A conductive layer is formed on the plastic substrate coated with the above-mentioned undercoating material by vacuum evaporation, ion blasting or sputtering, followed by heating and post-hardening.

Examples of the present invention will be shown below.

Example 1 A polyether sulfon film gold having a thickness of 100 μm was used as a base material. This film was coated with an acrylic resin that is cured by heat and ultraviolet light as a coating resin to a thickness of 5 μm, and pre-cured to a curing reaction rate of 60 inches.

This resin has excellent workability because it cures quickly with ultraviolet light. This acrylic resin had a pencil hardness of 4H when completely cured.

After undercoating in this manner, a conductive film was entirely formed by the snot tuttering method. The conditions were to use a magnetron type sputtering device and to use oxygen at 1.5 vo 1.
By introducing argon into the system, the adhesion rate was 180 people/
I went with fnin.

The film thickness was set at 450 people. This was completely heated and the curing reaction was completed. The transparent conductive film thus obtained had a sheet resistance of 2800 and a visible light transmittance of 82%. Abrasion resistance was evaluated by rubbing the sample several times with gauze that had been applied with a load. The alkali resistance was evaluated by immersing the sample in 10% sodium hydroxide for 5 minutes.

No matter which test was conducted, there was almost no change in resistance value and the results were good. In addition, all of the following studies were conducted as a comparative example.

Comparative Example 1 A conductive film was formed under the same conditions as in Example without undercoating a 100 μm polyether sulfone film. In this case, the resistance value was 600Ω, which resulted in poor scratch resistance and alkali resistance.

Comparative Example 2 A transparent conductive film was produced using the same resin as in Example 1 as the coating w resin, but with a curing reaction rate of 90% by pre-curing, under the same conditions as in the Example. In this case, the scratch resistance and alkali resistance were poor and it was unsuccessful.

Comparative Example 8 When completely cured as coating resin, pencil hardness is 7
A transparent conductive film was produced using an acrylic resin having a temperature of up to H under the same conditions as in the example. In this case, the sheet resistance was 2000Ω.

Comparative Example 4 In the case of completely curing FC as a coating resin, a transparent conductive film was prepared under the same conditions as Example 1 using an acrylic resin with lead g and hardness IH. Created.

In this case, the scratch resistance was poor.

The above results are summarized in Table 1, and as is clear from Table 1, it can be seen that the non-examples had a better ft% than the transparent conductive films produced under other conditions.

Claims (1)

[Claims] (1) The molecular film is coated on one or both sides with a thermosetting resin that can be cured by heat, ultraviolet rays, or radiation, and the coated resin is precured to a total curing reaction rate of 80 to 70%, and then indium is cured. After forming a metal oxide layer containing as the main component by vacuum evaporation, ion blating or sputtering, it is heated to form a gold IR compound layer in the coating layer. Partial or complete embedding and curing reaction? Terminating t%
A method for producing a transparent conductive film.