JPH0611801B2 - Conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a conductive film using heterocyclic compounds.

[Prior art and its problems]

It has been well known for a long time that heterocyclic compounds are polymerized with an oxidizing agent to obtain an insoluble and infusible polymer. For example, when pyrrole produces a polymer such as pyrrole black or pyrrole red with an inorganic acid, iron chloride, benzoquinone, hydrogen peroxide, etc.
In Heterocyclic Chemistry (Advances in
Heterocylic Chemistry) 15:67 (1973).

Similarly, furan, thiophene, other heterocyclic compounds, or substituted derivative thereof are also polymers.

On the other hand, it is also known that a film-like polymer such as pyrrole, furan, or thiophene can be obtained by electrolytic polymerization in the presence of an appropriate organic electrolyte. For example, see Chemical Communication, page 635. (1
979), Japan Journal of Applied
Physics (Japan Journal of Applied Physics) 21
Volume (1982), Polymer Preprint Japan (Po
Lymer Preprints Japan) Volume 33 (1984) and many other reports.

Since all of these reports are electrolytic polymerization methods, it is difficult to increase the area of the film-shaped product (film).
Since the adhesion between the electrode substrate and the product is poor and only a thin film can be obtained, there are problems such as lack of mechanical strength and uniformity.

In order to solve these problems, it is being gradually improved from both aspects of the device and the method.

Recently, by contacting a polymer compound substrate containing a polymerization catalyst with a heterocyclic compound, the substrate surface, and
It is disclosed in JP-A-61-51 that a conductive polymer is formed inside.
No. 026, Japanese Patent Application Laid-Open No. 61-111336, Japanese Patent Application Laid-Open No. 61-157522.

In the above publication, the polymerization catalyst used for producing the conductive film is hydrochloric acid, an inorganic acid such as nitric acid, a halide of a transition metal, a sulfate, a nitrate, a peroxo salt,
It is described that any one of a peracid, a persalt, a quinone, a diazonium salt, a halogen and the like is used.

[Problems to be solved]

However, it cannot be said that all of the above-mentioned polymerization catalysts are excellent in terms of strength of oxidizing power for obtaining a conductive film, easiness of handling in production, cost and the like. In addition, various properties of the obtained conductive film, particularly conductivity and transparency (light transmittance), may be considerably lowered depending on the type of catalyst used. There were cases where it was not possible.

On the other hand, stability over time, which is one of the biggest problems of the conductive film, that is, the conductivity and the transparency greatly change with time, has been largely affected by the type of catalyst used. .

Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide a conductive film which has both conductivity and transparency and is stable over time.

[Means for solving problems]

In order to explain the above-mentioned problems, the present invention has conducted various studies on polymerization catalysts, and as a result, a polymerization catalyst for obtaining a conductive film excellent in conductivity and transparency (light transmittance) stability over time. The problem was solved by using an iron salt, particularly ferric perchlorate, or ferric bromide.

In order to produce the conductive film of the present invention, a polymerization catalyst is mixed with a polymer resin by a suitable method, a polymer resin containing this polymerization catalyst is formed into a film, and at least one side of a single film or a base film is formed. Then, a gravure coat, a blade coat, and a roll coat method are applied to form a composite film. A conductive film can be easily obtained by bringing this composite film into contact with the heterocyclic compound in a gas phase or a liquid phase.

Examples of the polymer resin used in the present invention include natural polymer compounds such as cellulose, starch, casein and natural rubber, semi-synthetic polymer compounds such as methyl cellulose, hydroxyethyl cellulose and carboxyethyl cellulose, polyvinyl alcohol, polyvinyl acetate, polycarbonate, polyvinyl butyral. , Polyacrylate, polymethacrylate, polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl chloride,
Polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene cyanide,
Organic synthetic polymers such as polybutadiene, polyisoprene, polyether, polyester, polyamide, silicone, polyvinylpyrrolidone, polyacrylamide, and polyethylene glycol, and derivatives thereof, which may be composed of one or two or more, may interact with the polymerization catalyst. Any one may be used as long as it has excellent action and does not cause denaturation such as aggregation and gelation.

As a method of mixing the polymerization catalyst with the polymer resin, a solvent (containing a mixed solvent) capable of dissolving both the oxidizing agent and the polymer resin may be used, and the mixture may be mixed, and the polymerization catalyst and the polymer resin may be compatible with each other. It does not matter even if it is made into an emulsion state by using a solvent that does not have a solvent. The film forming method may be any of the above-mentioned methods such as calendering, inflation, T-type soybean method, and solution casting, in which a polymer resin containing an oxidant is heated by melting the resin by heating. However, the solution casting method is preferred because it may soften, and therefore the polymerization catalyst may be deteriorated, modified, decomposed, and the catalytic activity may be lost.

Further, a composite film may be obtained by coating a polymer resin containing a polymerization catalyst on the base material made of the above polymer resin by gravure, roll, blade coating or the like.

The present invention, when mixed and dissolved with a binder resin, examines aggregation, gelation of the resin, solubility of an oxidizing agent, etc., and among iron-based and copper-based salts, particularly strong oxidizing power, perchlorine. The target conductive film was obtained by using either ferric acid or ferric bromide. Here, even if a conductive film is produced using a polymerization catalyst having a large oxidizing ability, the changes in conductivity and transparency with time are extremely large. It is considered that this is related to the interaction between the polymer composed of the heterocyclic compounds, the anion component of the polymerization catalyst used, and the interaction with the residual catalyst.

Heterocyclic compounds include pyrroles and substituted pyrroles such as N-alkylpyrroles, N-arylpyrroles, monoalkylpyrroles substituted at the 3-position and monohalogenated pyrroles and dialkylpyrroles substituted at the 3- and 4-positions. And dihalogenated pyrroles, thiophenes, substituted thiophenes such as monoalkylthiophenes and monohalogenated thiophenes substituted at the 3-position, dialkylthiophenes and dihalogenated thiophenes substituted at the 3- and 4-positions, anilines and derivatives thereof, such as , N-alkylaniline, N-dialkylaniline, halogenated aniline, dihalogenated aniline, halogenated-N-alkylaniline, halogenated-
N-dialkylaniline, dihalogenated-N-acetylaniline, phenylenediamine and its substituted N-alkylphenylenediamine, N.I. N-dialkylphenylenediamine, N.I. Examples thereof include N'-dialkylphenylenediamine, and one or more of the above compounds can be used in combination. It is preferable to use pyrrole from the viewpoint of stability. As a method for contacting the heterocyclic compound and the polymer resin containing the polymerization catalyst, the heterocyclic compound vapor or the vapor in which an inert gas coexists is exposed to the polymer resin containing the polymerization catalyst. Alternatively, the resin may be dipped in a solvent in which heterocyclic compounds are dissolved, but the conductivity and transparency of the resulting conductive film are not required, and the dry process does not require post-treatment such as washing and drying. From the viewpoint of the process, the gas phase state is preferable.

[Work]

As described above, the present invention is a result of examining various types of polymerization catalysts,
By using ferric perchlorate or ferric bromide, there is no interaction with the anion component of the polymerization catalyst or residual catalyst, and a conductive film with excellent stability over time can be obtained. It was

Example 1 Polyester film 12 μm thick (Toray, P-11) One side was coated with a catalyst-containing binder resin ^* by blade coating to obtain a composite film. This composite film
It was left for 5 minutes in a 0.032 m ³ reaction chamber consisting of a pyrrole / air mixed atmosphere at 25 ° C. The absolute amount of pyrrole concentration in this reaction chamber was unknown.

* Binder resin containing catalyst [Example 2] A conductive film was produced under the same conditions as in Example 1 except that the catalyst-containing binder resin had the following composition.

[Comparative Examples 1 to 8] Polymerization was carried out under the same conditions as in Example-1, and the second chloride was used as a catalyst.
Iron, cupric chloride, ferric sulfate, cupric sulfate, cupric sulfate
The conductive films produced using iron, cupric sulfate, cupric bromide and cupric perchlorate were designated as Comparative Examples 1 to 8. The surface resistance values and light transmittances of the conductive films obtained from the above Examples 1 and 2 and Comparative Examples 1 to 8 are shown in Table 1 below.

As is clear from the results, in Examples 1 and 2 and Comparative Examples 1, 2 and 7, the surface resistance was 10 ³ to 10 ⁴ Ω / □, and better conductivity was obtained than the others. With respect to these films for which good results were obtained, the conductive light transmittance after one month was measured. The results are shown in Table-2.

As is clear from Table 2, the films of Examples 1 and 2 have a surface resistance and a light transmittance which are much smaller than those of the others and maintain the physical properties immediately after the production of the conductive film. ing.

[Effect]

INDUSTRIAL APPLICABILITY As described above, the present invention is a powdery salt, and by using either ferric perchlorate or ferric bromide, which is easy to handle in production, as a polymerization catalyst, it is extremely stable as never before. In addition, it is possible to obtain a conductive film excellent in conductivity and temporal stability of light transmittance, and it becomes easy to use a conductive film using a heterocyclic compound.

Claims (2)

[Claims] 1. A polymer film, which is made electrically conductive by bringing a polymer resin containing a polymerization catalyst into contact with a heterocyclic compound, as a polymerization catalyst, ferric perchlorate, ferric bromide, etc. A conductive film characterized by using one of iron. 2. The heterocyclic compounds are pyrrole, thiophene, furan, aniline, and alkyl-substituted compounds thereof,
The conductive film according to claim 1), which is one or two or more compounds selected from induction charges.