JPH06101243B2 - Method for manufacturing composite conductive film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a method for producing a conductive film, and more specifically, by using an organic solvent for reacting and forming a conductive polymer as a resin solvent as it is, The present invention relates to a method for producing a composite conductive film in which a conductive polymer is uniformly dispersed.

[Conventional technology]

Metal powder such as gold and silver, conductive filler such as graphite and carbon black is kneaded into synthetic resin, or mixed with resin varnish to form a film as a solution to make electrically insulating polymer conductive. The composite conductive film is well known, and this composite conductive film is widely used for applications such as electrode / circuit materials and antistatic. Further, by bringing a heterocyclic compound, for example, pyrrole, into contact with a polymer film containing a polymerization catalyst such as an oxidizing agent in a gas phase, polypyrrole is generated on the surface and inside of the resin, and a film having high conductivity is obtained. It is also known. (JP-A-61
It is also known that conductive polypyrrole is generated on the surface and inside of the resin by coating polyvinyl chloride or the like on the electrode and electrolytically oxidatively polymerizing a pyrrole solution containing an electrolyte. . (Refer to JP-A-60-105532) [Problems to be solved by the invention] However, in the conventional conductive filler composite type conductive film, it is difficult to miniaturize the conductive filler and uniformly disperse it in the resin. There is a problem that the film thickness cannot be made too thin. Even in a complex system using a conductive polymer, the gas phase polymerization method requires a large closed system device to make the film conductive, and there is a problem that the reaction takes too long. In the polymerization method, the reaction is initially performed through an electrically insulating film, so a thick film cannot be obtained, and since the film is peeled from the electrode after the reaction, a thin film cannot be used in terms of mechanical strength. There is.

The present invention has been made in view of such circumstances, and its main purpose is to use an organic solvent as a place for reacting a conductive polymer having conductivity, as a solvent for continuously dissolving and dispersing a resin. Then, the reaction of forming a conductive polymer in a unit of seconds to minutes is caused, and before the reaction polymer is precipitated / aggregated, it is uniformly dispersed in the dissolved / dispersed resin, and as a varnish. It is another object of the present invention to provide a method for producing a conductive film in the form of a continuous film or a pattern by obtaining the same.

[Means for solving problems]

That is, the present invention is to prepare a solution of an oxidative polymerization catalyst, which itself acts as a dopant, in an organic solvent while stirring at a low temperature of 0 ° C. or lower, while polymerizing a monomer expressing conductivity to 1 mol of the oxidative polymerization catalyst On the other hand, after adding and introducing 0.2 to 1 mol to produce a conductive polymer, the solution has a solubility in the organic solvent while being stirred at a temperature not lower than room temperature and not higher than the boiling point of the organic solvent. Then, a resin having film forming ability is added and mixed to obtain a conductive polymer dispersed resin solution. Then, after coating or casting the solution on a substrate, the organic solvent was dried and removed to form a film, and the film was washed to remove the unreacted oxidative polymerization catalyst.

As the polymer having conductivity in the present invention, a polymer which is stable in a conductive state (oxidized / polymerized state) is preferable, and it is necessary to be capable of electroless polymerization. As the monomer that polymerizes to exhibit conductivity, a heterocyclic compound such as pyrrole, or a derivative thereof, aniline, or one or more compounds of an aniline derivative is preferable.

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 their derivatives, such as , N-alkylaniline, N-dialkylaniline, halogenated aniline, dihalogenated aniline, halogenated-N-alkylaniline, halogenated-
Examples thereof include N-dialkylaniline, dihalogenated-N-acetylaniline, phenylenediamine and its substituted N-alkylphenylenediamine, NN'-dialkylphenylenediamine, NN'-dialkylphenylenediamine, and one of the above compounds or Two or more kinds can be used in combination.

The polymerization catalyst itself acts as a dopant after the reaction, and includes ferric chloride, cupric chloride, molybdenum chloride,
Metal salts such as ruthenium chloride, metal oxides such as lead dioxide, peroxo salts such as potassium persulfate and ammonium persulfate, quinones such as benzoquinone, diazonium salts such as benzenediazonium chloride, potassium ferricyanide, hexachloroplatinum (IV) acid, etc. However, ferric chloride, particularly anhydrous ferric chloride, is most preferable from the viewpoint of solubility in an organic solvent as a reaction field and solvent for dissolving resin, and conductivity obtained.

The organic solvent used in the present invention is preferably diethyl ether, acetonitrile, ethyl acetate, or nitromethane, and examples of usable organic solvents include xylene, benzene, hexane, carbon tetrachloride, and tetrahydrofuran. In addition, these organic solvents
Water may be mixed within the range of not more than 10%, but using water itself as a solvent defines a low temperature reaction of 0 ° C. or lower in the present invention, and defines the physical properties of the finally obtained film. It is not preferable because of physical properties such as water resistance of the resin.

The conductive polymer dispersed in the resin is carried out as a solution electroless reaction in an organic solvent, but the reaction is completed quickly in a few seconds to a few minutes. The conductivity of the resulting polymer changes depending on the type of polymerization catalyst as a dopant and the type of organic solvent, but in order to form a more regular molecular structure and a long conjugated system, for the purpose of preventing side reactions, It is necessary to carry out the reaction at a lower temperature, and it is desirable to set the temperature to a low temperature of 0 ° C. or lower, including that the polymerization reaction is an exothermic reaction.

A conductive polymer is produced by introducing the above-mentioned monomer in a solution form or as a gas into an organic solvent solution in which a polymerization catalyst is dissolved in advance. The conductivity is good.

Although the reaction becomes faster as the amount of the oxidation polymerization catalyst increases, the obtained conductivity tends to deteriorate, but when the amount exceeds a certain amount, the conductivity does not change so much. Further, the reaction proceeds in the same manner even when 10 mol or more of the oxidative polymerization catalyst is used with respect to 1 mol of the monomer, but when it is combined with the resin later, unreacted catalyst remains in the film even if washed. This remains a cause of deterioration of the composite conductive film over time (conductivity deteriorates with time).

Therefore, 0.2 to 1 mol of the monomer is added and introduced with respect to 1 mol of the oxidation polymerization catalyst.

The polymer produced is fine particles of 0.5 μ or less, but usually has a specific gravity of often more than 1, and in order to avoid precipitation / aggregation and improve reaction efficiency, in the present invention, the above steps are continuously performed. It is important to stir.

Next, in the step of adding the resin to the organic solvent dispersion liquid containing the conductive polymer, first, the entire solution is heated to room temperature or higher, and a resin having a film-forming ability dissolved in the same solvent in advance is added. By mixing and stirring, a resin solution in which the conductive polymer is uniformly dispersed is obtained. It is not particularly limited to add an additive such as silica or a coupling agent to the solution in order to adjust the viscosity of the solution or to improve the physical properties of the obtained film.

The resin used in the resin solution is not particularly limited as long as it has solubility in the organic solvent and has film-forming ability, and polyester-based, polyamide-based, polyvinyl chloride, polyvinyl acetate, butyral, vinyl chloride. − Vinyl acetate,
Various resins may be used alone or in combination depending on the application of the final film such as acrylic resin. If desired, a curing agent such as isocyanate may be used in combination for crosslinking.

The obtained resin solution is coated or cast on a substrate such as a synthetic resin film or a metal foil by a known method, and then the organic solvent is dried and removed to form a film, and the film is formed from the substrate as necessary. By peeling or as it is, the film is washed with a solvent such as water and alcohol which dissolves the catalyst but does not dissolve the resin, in particular, the unreacted oxidative polymerization catalyst remaining on the film surface is removed to produce a composite conductive film. Was done.

[Action]

In the present invention, the conductive polymer is produced in an organic solvent in a short time, and the resin is directly added to and mixed with the organic solvent in which the produced conductive polymer is dispersed.・ The process of re-addition and mixing is omitted,
In addition, the conductive polymer particles are aggregated as they are generated.
Since it is uniformly mixed with the resin when it does not precipitate, it is possible to produce an excellent composite conductive film having excellent dispersibility of the conductive polymer in the resin and stable conductivity when formed into a film.

〔Example〕

As an oxidative polymerization catalyst, 16.2 g (0.1 mol) of anhydrous ferric chloride FeCl ₃ was dissolved in 300 ml of a solvent of ethyl acetate / diethyl ether = 9/1. As the container, a glass container with a stirrer of 1 is used. While maintaining and stirring this solution at −5 ° C., 5 ml (0.07 mol) of pyrrole (C ₄ H ₅ N) as a monomer was added thereto and reacted. The reaction occurs immediately after adding pyrrole,
The solution turned brown. After continuing stirring at -5 ° C for 10 minutes, warm the whole container to 30 ° C, add 400 ml of 25% solution of linear polyester resin dissolved in ethyl acetate to this, and stir for another 20 minutes to remove brown tea. A resin solution that was slightly dark in color was obtained.

This resin solution was added to a biaxially stretched polyester film (thickness
25 μ) was gravure coated with a 150-60 μ gravure plate, and the solvent was dried off to obtain a single-sided conductive film.
The thickness of the coated composite conductive film layer was 2.4μ.

This composite film was immersed in methanol / water = 3/7 solvent, washed, and dried to finally obtain a composite conductive film. The physical properties are described below.

Conductivity-Surface resistance value 3.2 × 10 ³ Ω / □ Light transmittance-41% at 550mm Heat sealability Face-face 180 ℃ -1sec 0.82kg / 15mm Face-Al ^9μ / PET ^12μ 180 ℃ -1sec 1.13kg / 15mm * The electric conductivity of the polymer before addition of the resin was 7 Ω ^-1 cm ^-1 as pressed powder.

〔The invention's effect〕

As described in detail above, according to the present invention, a composite conductive film having a wide range of physical properties can be obtained very easily.

Further, according to the present invention, a resin solution containing a conductive polymer can be easily obtained using a reaction kettle or the like that has been frequently used in the chemical industry, and roll coating, by controlling the concentration and liquid viscosity of the resin, Gravure coat, screen printing,
Not only can a composite conductive film be obtained by various methods such as blade coating, but a film in which a conductive polymer of fine particles is uniformly dispersed, which has been difficult with conventional carbon black or the like, can be obtained. Further, the unreacted oxidative polymerization catalyst is removed by washing by limiting the ratio of the oxidative polymerization catalyst and the monomer used for the polymerization, so that the deterioration with time hardly occurs when the conductivity is deteriorated.
As a result, the strength of the film is less deteriorated, and a composite conductive film having a light-transmitting property can be obtained by changing the ratio of the resin and the polymer, which is a very great commercial advantage.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01B 5/14 Z

Claims (1)

[Claims] 1. An oxidative polymerization catalyst, which itself acts as a dopant, is dissolved in an organic solvent, and then the solution is stirred at a low temperature of 0.degree. After introducing 0.2 to 1 mol with respect to 1 mol to generate a conductive polymer, while stirring the solution at room temperature or higher and the boiling point of the organic solvent or lower,
A resin having solubility in an organic solvent and having film-forming ability is added and mixed to prepare a conductive polymer-dispersed resin solution, which is coated or cast on a substrate, and then the organic solvent is dried and removed. A method for producing a composite conductive film, which comprises removing the unreacted oxidative polymerization catalyst by forming the film into a film and then washing the film.