JPH01131288A - Electrically conductive coating - Google Patents

Abstract

PURPOSE:To obtain the title coating having high electrical conductivity, capable of forming thin coating film, also easy to form transparent coating film, suitable for use in the filters for VDT, by dissolving a specific electrically conductive polymer in a solvent. CONSTITUTION:The objective coating can be obtained by dissolving (A) an electrically conductive polymer with an electrical conductivity of >=10<-6>S/cm<2> (pref. >=10<-3>S/cm<2>) (pref. polyaniline or its derivative) in (B) a solvent such as N,N'-dimethylformamide or N-methyl-2-pyrrolidone. In order to enhancing the processibility and durability of said coating, a thermoplastic resin such as polyester or polystyrene, thermosetting resin such as epoxy or urethane resin, or semisynthetic polymer such as cellulose acetate or nitrocellulose may be incorporated in said coating.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to electrostatic shielding, antistatic, transparent conductive films,
6 Regarding conductive paints suitably used for producing electrochromic elements, VDT (visual display terminal) filters, etc. Problems to be solved by conventional techniques and inventions Conventionally used conductive paints are: Most materials were made by dispersing conductive fine powder such as carbon or graphite or metal fine powder such as silver or nickel in a polymer binder together with a solvent. However, in these conductive paints, conductive fine powders come into contact with each other to impart conductivity, or
Alternatively, since it is necessary to be close to within several people, it is necessary to increase the amount of conductive fine powder blended in order to increase the conductivity. In addition, conductivity changes due to differences in the dispersion state of the conductive fine powder and differences in the surface condition after forming the molded product, and it is necessary to increase the thickness of the coating film in order to obtain appropriate conductivity. It had drawbacks such as difficulty in becoming transparent and conductive.

The present invention was made in view of the above circumstances, and it is possible to reduce the thickness of a conductive paint film after molding, and it is also possible to form a transparent paint film that has high conductivity. The purpose is to provide an easy conductive paint.

In order to achieve the above object, the inventors of the present invention have carried out extensive research and have found that it is 10-6 S/cm or more, preferably 10-3
By dissolving a conductive substance having a conductivity of 8/am or more, such as polyaniline or its derivatives, in a solvent, and further dissolving other film-forming polymer substances in the solvent as necessary, conductivity with excellent properties can be obtained. It was discovered that a polyester paint can be obtained. That is, the coating film obtained with this conductive paint is
having high conductivity based on the film of the conductive substance,
Even when a very thin coating film is formed, it maintains good conductivity, and when used in combination with other film-forming polymer substances, the processability and durability are further improved. Spin Co-1 is applied to various coated objects such as metals, polymer films, etc.
It is also possible to form a coating film by a method, etc., and therefore, the present invention was realized based on the finding that the coating material of the present invention can be advantageously used for forming a conductive coating film.

The present invention will be explained in more detail below.

The conductive paint according to the present invention is made by dissolving a conductive polymer substance in a solvent.
-'S/an or more and any material can be used as long as it is soluble in a suitable solvent.

Specifically, polyaniline and derivatives thereof, polypyrrole and polythiophene which have been made solubilized by introducing an alkyl group, etc. are preferably used. Among these, highly stable polyaniline and its derivatives are preferred, and polyaniline is particularly preferred.

In this case, polyaniline or its derivatives are prepared by mixing aniline or its derivatives with platinum, gold, carbon, etc. in an acidic solution.
An electrolytic polymerization method in which polyaniline or its derivatives are obtained by electrolytic oxidation using an anode made of stainless steel or the like, and a method in which aniline or its derivatives are oxidized in an acidic solution with an oxidizing agent such as iron chloride or ammonium persulfate 11 to produce polyaniline or its derivatives. Those obtained by any of the chemical oxidative polymerization methods (catalytic polymerization methods) for obtaining derivatives can be suitably used. In the present invention, the derivatives of polyaniline include: [In the formula, R1 to R0 are each a hydrogen atom, an aryl group, an alkyl group, No, NlI2. CF3° represents the same or different groups selected from aryl groups or alkyl groups. ] etc.

Here, when polyaniline or its derivatives are obtained by electrolytic oxidation polymerization, acids such as hydrofluoric acid, hydrochloric acid, nitric acid, perchloric acid, fluoroboric acid, sulfuric acid, acetic acid, phosphoric acid, etc., especially hydrochloric acid, borofluoric acid, etc. Using hydrohydric acid, the aniline concentration is usually 0.01 to 5 mol/Q, more preferably 0.5 to 3 mol/Q, and the acid concentration is 0.02 to 10 mol/Q, more preferably 1 to 6 mol/Q. 1:) using an electrolytic solution having the composition Q is suitable.

When polyaniline or its derivatives are obtained by a chemical oxidative polymerization method, 0.01 to 5 mol/Q, more preferably 0.01 to 5 mol/Q, more preferably 0.01 to 5 mol/Q, is added to a polymer solution having the same composition as the electrolytic solution used in the electrolytic oxidative polymerization method. The one to which 5 to 3 mol/Ω of oxidizing agent is added is preferably used. As the type of oxidizing agent, known oxidizing agents such as ferric chloride, ammonium persulfate, potassium dichlorate, and potassium permanganate are used, and ferric chloride and ammonium persulfate are particularly preferably used.

The conductive polymer such as polyaniline thus obtained can be used without being dedoped, and can be dissolved in a solvent to form a conductive paint. As for the type of solvent, any solvent that dissolves the conductive polymer may be used, but for example, in the case of polyaniline or its derivatives, N,N'-dimethylformamide, N-methyl-2-pyrrolidone, etc. are preferably used. .

Furthermore, in order to improve processability, durability, etc., other film-forming polymers may be dissolved or mixed in the conductive paint of the present invention. In this case, the polymer may be any polymer that dissolves in the above solvent, including thermoplastic resins such as polyester, polystyrene, polycarbonate, polyvinyl chloride, and acrylic resins; curable resins such as epoxy and urethane; Alternatively, it may be a biologically derived polymer such as cellulose acetate or cellulose 21-helocellulose, or a derivative thereof. Note that two or more types of these polymers may be mixed. In this case, the mixing ratio of the conductive polymer and the film-forming polymer is 100 parts by volume of polyaniline or its derivative.
1 to 600 is preferable.

It should be noted that pigments and the like may be further blended into the coating material of the present invention.

The conductive paint thus obtained is applied onto an object to be coated, such as glass, metal, or polymer film, and the solvent is removed at room temperature or under heating. In this case, the painting method is
The coating method, dip method, spray method, spin code method, screen printing method, etc. are used, but when obtaining a conductive polymer thin film with a thickness of about 1 Lop or less, the spin code method is used.
When obtaining a thick film of 0.04 or more, screen printing is preferably used.

As mentioned above, the conductive paint of the present invention is made by dissolving a conductive polymer such as polyaniline or its derivatives in a solvent. According to the coating method using this paint, a conductive polymer thin film is formed. It is also suitable as a method for obtaining it easily. That is, conductive polymer thin films have conventionally been obtained on electrode substrates by electrolytic polymerization, or by direct chemical oxidative polymerization on substrates, but with the use of the conductive paint of the present invention, Not only on electrode substrates, but also on glass, metal,
Since it is possible to form a thin film of conductive polymer with a uniform purity of 0.14 or less on a substrate such as a polymer film, it is possible to form a thin film of conductive polymer with a uniform purity of 0.14 or less. Using a conductive paint made of a conductive polymer provides a simple method for manufacturing an electrochromic element drive section.

Furthermore, since the present invention can form a transparent coating film and also has characteristics such as conductivity, it is suitable for use as a conductive paint for producing filters for VDT (visual display terminal). The range of applications is very wide.

Effects of the Invention As explained above, if the conductive paint of the present invention in which a conductive polymer such as polyaniline or its derivative is dissolved in a solvent is used, it can be applied to coating methods, dip methods, spray methods, spin code methods, screen methods, etc. A conductive polymer coating film with good adhesion to the object to be coated can be easily formed on any material using methods such as printing, and it is also possible to reduce the thickness of the coating film, making it highly cost-effective. A conductive polymer film having conductivity can be obtained.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples and comparative examples, but the present invention is not limited to the following examples.

〔Example〕

In an acidic aqueous solution containing 1 mol/Q of aniline and 2 mol/Q of fluoroboric acid, stainless steel or steel was used as an anode.
(SUS316), a punched metal made of SUS316 was used as the cathode, and polyaniline was deposited on the anode by electrolytic polymerization.

After the polymerization was completed, the obtained polyaniline was washed with ion-exchanged water. Drying was carried out at 30°C until the weight became constant.

The obtained polyaniline sheet was cut into small pieces along with the electrodes, dissolved in 100-N,N'-dimethylformamide, filtered, and concentrated to obtain a polyaniline conductive paint (polyaniline concentration: 4.6% by weight).

0.5 d of the obtained conductive paint was spin-coded onto a polyethylene terephthalate film at a rotational speed of 300 rpm and dried at room temperature. The thickness of the coated polyaniline thin film was 0.1%, and the sheet resistance was 5×10 sΩ/hole. Moreover, the light transmittance at 500 r+m was 90%.

[Comparative example]

A commercially available conductive carbon paste was diluted 10 times with acetone, 0.5- was spin-coded onto a polyethylene terephthalate film at a rotational speed of 300 rpm, and dried at room temperature. The thickness of the coated conductive layer was 0.1p, and the sheet resistance was I x 10''07 or more.The light transmittance at 500 nm was 10%.

Applicant: Brideston Co., Ltd. Agent: Patent Attorney Takashi Kojima

Claims (1)

[Scope of Claims] 1. A conductive paint characterized by dissolving a conductive polymer substance having a conductivity of 10^-^6S/cm or more in a solvent. 2. The conductive paint according to claim 1, wherein the conductive polymer material is polyaniline or a derivative thereof.