JPH0451584B2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> By doping the aniline polymer,
The resulting conductive polymer has high conductivity and also has good stability. Furthermore, the conductivity of conductive polymers obtained from aniline polymers can be controlled over a wide range by controlling the amount of dopant. Therefore, by utilizing these properties, various applications such as various sensors, EMI materials, and antistatic materials can be considered.

In addition to high conductivity, the conductive polymer has redox properties that allow reversible doping and dedoping, and since it can be obtained in powder form, it has a large surface area. It is useful as a secondary battery and various electrode materials that take advantage of its properties.

<Prior art> Methods for producing aniline polymers include oxidative polymerization using aniline itself in the presence of a chemical oxidizing agent and water as a solvent, and electrolytic oxidative polymerization in the presence of water or an organic solvent with an appropriate acid or electrolyte. Examples include a method of depositing on an anode plate.

Regarding the structure of aniline polymer containing hydrochloric acid,
The following structure was proposed at ICSM'86 by the present inventors, A.G. Matsuku Diarmid et al.

As can be seen from this structure, the aniline polymer has a polyionic structure, is insoluble and infusible, and has extremely poor formability. When considering the application of the polymer, it is preferable to use molding methods such as melt molding and coating. Conductive polymers are generally rigid and therefore often have extremely poor solubility. Therefore, several methods have been attempted to dissolve conductive polymers.

As a method for dissolving conductive polymers, as shown by the present inventors in Japanese Patent Publication No. 59-053300,
A method has been proposed in which a triazole polymer is dissolved in a solvent consisting of iodine as a dopant and acetone as a solvent, or a solution consisting of ferric chloride as a dopant and nitromethane as a solvent. However, the aniline polymer of the present invention and this triazole polymer are significantly different in structure and properties. Furthermore, as shown in US Pat. No. 4,452,727, it is known that polyphenylene sulfide is dissolved in a solution consisting of AsF ₅ as a dopant and AsF ₃ as a solvent. This case is also a special combination and cannot be said to apply to the present invention, and furthermore, AsF ₅ is a highly toxic solvent and poses many problems in terms of handling.

In order to solubilize the aniline polymer, a long-chain alkyl group was introduced into the aromatic nucleus in JP-A-61-
Proposed in No. 204266. However, although the solubility is improved by introducing a long-chain alkyl group, the electrical conductivity, which is the original objective of the conductive polymer, is significantly reduced, which poses a serious problem from the viewpoint of practical application. As a result of intensive study on a method for improving moldability by dissolving a polymer obtained from the simplest aniline itself, the present inventors discovered that an aniline polymer can be dissolved in an inert polar organic solvent containing a specific amount of Lewis acid. The present invention was completed based on this discovery.

<Structure of the present invention> The present invention involves applying a Lewis acid to an aniline polymer.
A conductive resin solution composition characterized in that the polymer is dissolved in an inert polar organic solvent containing 100% by weight or more.

Hereinafter, specific contents of the present invention will be explained in detail.

The aniline polymer of the present invention can be easily obtained by using a chemical oxidizing agent in the presence of aniline and an inorganic and/or organic acid, or by carrying out electrolytic oxidation polymerization in the presence of aniline and an inorganic and/or organic acid.

Moreover, according to this method, anions coexisting in the reaction system are simultaneously incorporated into the resulting polymer as a dopant, so that high conductivity is developed even without doping with an electron-accepting compound.

Specific examples of the inorganic or organic acids used in this case include the following.

Hydrochloric acid, sulfuric acid, hydroborofluoric acid, hydrobromic acid,
Hydroiodic acid, perchloric acid, phosphoric acid, acetic acid, oxalic acid, trifluoromethanesulfonic acid, nonafluorobutanesulfonic acid, methanesulfonic acid, octanesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid or alkali salts thereof compound, ammonium salt compound is used. It is not necessarily limited to this.

A known chemical oxidizing agent may be used. Specific examples include persulfate compounds such as ammonium persulfate and potassium persulfate, and dichromic acid compounds such as potassium dichromate.

Electrolytic oxidative polymerization is carried out at constant potential or constant current, and platinum plates, glassy carbon plates, palladium plates, etc. are preferably used as anode materials.

As a solvent for chemical oxidation or electrolytic oxidation polymerization,
Although water is mainly used, organic solvents such as acetonitrile and propylene carbonate are also used. In addition, in order to use an organic solvent as a solvent, the above-mentioned inorganic or organic acid is used in the form of a salt.

The obtained aniline polymer is insoluble and infusible no matter which method is used to polymerize it. The product obtained by polymerization is the so-called acid addition type. A form obtained by neutralizing this product with an alkali or the like can also be used in the present invention. This polymer can be dissolved by using an inert polar organic solvent containing 100% by weight or more of Lewis acid based on the polymer. When a neutralized polymer is dissolved in a solution containing this Lewis acid, doping occurs at the same time and it exhibits high electrical conductivity.

Examples of Lewis acids used in the present invention include FeCl ₃ , SbCl ₅ , SbF ₅ , ZrCl ₄ , TaF ₅ , BF ₃ ,
Examples include BCl ₃ , WCl ₅ , SnCl ₄ and the like. Preferably, Group 3 metal anhydrous chlorides such as FeCl ₃ and AlCl ₃ are used.

Examples of the solvent include organic nitro compounds such as nitromethane, nitropropane, and nitrobenzene, which are often used as solvents for Friedel-Crafts reactions, and halogen compounds such as thionyl chloride. Among these, nitromethane is preferably used.

The Lewis acid is preferably used in an amount of 0.01% to 50% by weight based on the solvent. By mixing the polymer into a solution containing these Lewis acids and stirring, the desired conductive resin solution composition can be easily obtained. The solubility of the polymer in the solution varies depending on the type and concentration of Lewis acid and the type of solvent, but if the Lewis acid is 100% by weight or more based on the polymer,
The solution composition can be obtained by using preferably 150% by weight or more, more preferably 200% by weight or more. When the Lewis acid content is less than 100% by weight, doping occurs but dissolution does not occur. At this time, add 0.1g of polymer to 1 liter of solvent.
Approximately 200g can be dissolved. These are initially non-uniform, but by stirring they become a homogeneous solution or a highly viscous pasty solution. A film-like molded body can be obtained by applying these solutions by a casting or coating method and removing the solvent. On the other hand, excess Lewis acid can be extracted and removed by using a solvent that dissolves it.

The present invention will be explained in detail with reference to Examples below. However, the present invention is not limited to this. Here, parts refer to parts by weight.

Polymerization Example 1 93 parts of aniline was dissolved in 8000 parts of a 2.25N hydrochloric acid aqueous solution. A solution of 342 parts of ammonium persulfate dissolved in 1000 ml of water was added to this solution while stirring.
The mixture was added dropwise at 5°C over 1 hour. Subsequently, the mixture was stirred at the same temperature for 4 hours, and the resulting dark green precipitate was filtered, washed with water and acetonitrile, and dried at 50°C to obtain 105 parts of a hydrochloric acid addition type aniline polymer. This material was molded into a disk shape, and its electrical conductivity was measured by the four-terminal method to find it to be 17 S/cm.

100 parts of a hydrochloric acid addition type aniline polymer was suspended in 5000 parts of a 2N aqueous sodium hydroxide solution and heated under reflux for 10 hours. After filtering the obtained precipitate, wash it with a large amount of water for 10 minutes.
The mixture was boiled for several hours, washed, filtered, washed with water, and dried to obtain a dehydrochloric acid type aniline polymer. The conductivity of a molded product was 10 ^-10 S/cm or less, and it was an insulator.

Example 1 4 parts of anhydrous ferric chloride was dissolved in 100 parts of nitromethane, and 1 part of the hydrochloric acid addition type aniline polymer powder obtained in Polymerization Example 1 was added thereto. A clear solution was obtained after stirring for 8 hours at room temperature. When this was concentrated to 1/10, it became a highly viscous solution. When this material was casted with a doctor blade to remove the solvent, a self-supporting conductive film could be obtained. The electrical conductivity of this product was 16 S/cm, which was the same as that of molded powder before melting.

Example 2 4 parts of anhydrous ferric chloride was dissolved in 100 parts of nitromethane, and 1 part of the neutralized aniline polymer powder obtained in Polymerization Example 1 was added thereto. A clear solution was obtained after stirring for 8 hours at room temperature. When this was concentrated to 1/10, it became a highly viscous solution. Doctor this thing.
By casting with a blade and removing the solvent, a self-supporting conductive film could be obtained. The conductivity of this material was 18 S/cm, and doping occurred simultaneously with dissolution, resulting in high conductivity. The electrical conductivity was at the same level as the hydrochloric acid addition type aniline polymer shown in Polymerization Example 1.

Example 3 3 parts of anhydrous ferric chloride was dissolved in 100 parts of nitromethane, and 1 part of p-toluenesulfone-added aniline polymer powder was added thereto. A clear solution was obtained after stirring for 8 hours at room temperature. When this was concentrated to 1/5, it became a highly viscous solution. When this material was casted with a doctor blade to remove the solvent, a self-supporting conductive film could be obtained. The electrical conductivity of this product was 6 S/cm, which was the same as that of the powder molded before melting.

Example 4 5 parts of anhydrous aluminum chloride in 100 parts of nitromethane
1 part of p-toluenesulfone-added aniline polymer powder was added to the solution. A clear solution was obtained after stirring for 8 hours at room temperature.

Comparative Example 1 1 part of anhydrous ferric chloride was dissolved in 100 parts of nitromethane, and 2 parts of the hydrochloric acid addition type aniline polymer powder obtained in Polymerization Example 1 was added thereto. Even after stirring at room temperature for 24 hours, a homogeneous solution was not obtained.

Comparative Example 2 1 part of anhydrous ferric chloride was dissolved in 100 parts of nitromethane, and 3 parts of the neutralized aniline polymer powder obtained in Polymerization Example 1 was added thereto. Even after stirring at room temperature for 24 hours, a homogeneous solution was not obtained.

Claims (1)

[Claims] 1 100% of metal anhydride chloride for aniline polymer
A conductive resin solution composition characterized in that the polymer is dissolved in an inert nitro compound organic solvent containing at least % by weight. 2. The conductive resin solution composition according to claim 1, wherein the anhydrous metal chloride is anhydrous ferric chloride. 3. The conductive resin solution composition according to any one of claims 1 to 2, wherein the nitro compound is nitromethane.