JPH11292957A - Method for producing conductive fine particles - Google Patents

Abstract

(57) [Problem] To provide a method for producing conductive fine particles having various particle diameters, which have good conductivity and are stable with respect to environmental changes. SOLUTION: embedded image (Wherein R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or Represents an arylamino group or a substituent having a molecular weight of 100 or more substituted with an arylamino group, and X represents an NH group, a sulfur atom or an oxygen atom. (Wherein R ₃ and R ₄ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or Represents an arylamino group, and X represents an NH group, a sulfur atom or an oxygen atom).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing organic conductive fine particles.

[0002]

2. Description of the Related Art As conductive polymers, polyacetylene, polyparaphenylene, polyaniline, polypyrrole and the like are known. These conductive polymers can be obtained in the form of powder, granules, lump, or film, and their application to antistatic materials, electromagnetic wave shielding materials, and various electronic devices is being studied as it is or according to its use. Among these conductive polymers, polypyrrole is characterized by its excellent stability in air and easy handling, and is being studied.

For example, it has been known that, when pyrrole is polymerized in water with ferric chloride as a catalyst, conductive black polypyrrole containing chlorine anions as a dopant is obtained (Synthetic M).
et al., 20 (1987) 365-371). However, this product is a powder of several tens to 100 μm or so, and is an aggregate of polypyrrole particles. For this reason, molding was difficult, the density of the product was low, and the electrical characteristics were insufficient. JP-A-3-730 discloses the polymerization of pyrrole in the presence of an amphoteric polymer, a cationic polymer, a cationic surfactant, an anionic surfactant, a nonionic surfactant, an amphoteric surfactant and the like. To produce a polypyrrole-based aqueous dispersion. Since ionic substances, surfactants, and the like are mixed in the polypyrrole particles obtained by this method, the conductivity changes due to environmental fluctuations during use after production, and there is a problem in stability. JP-A-63-
193926 discloses a method of polymerizing pyrrole in an aqueous solution of polyvinyl alcohol as a dispersant. In this method, since polyvinyl alcohol remains in the molded body at the time of use, there are problems such as a decrease in conductivity and a change in conductivity in accordance with environmental changes. JP-A-7-118370 describes that polypyrrole particles having an average particle size of 0.2 to 10 μm and a narrow particle size distribution can be obtained by polymerizing pyrrole in an aqueous solution of an amide bond-containing polymer. There is.
However, the conductivity of the polypyrrole particles obtained by this method is low, which is inconvenient for use as a low-resistance conductive material. Langmuir, 1995, 11, 422
Nos. 2 to 4224 describe a method for synthesizing polypyrrole colloid particles using a thiophene-containing polymer as a stabilizer. In this method, particles having a uniform particle size can be produced, but there is a problem that it is difficult to synthesize a stabilizer and to control the particle size.

[0004] As another method, a method of electrochemically oxidizing polymerization (electrolytic polymerization) is known. In this method, since polypyrrole is formed on the anode in the form of a film, the size of the product is restricted by the size of the electrode, and furthermore, there is an inconvenience that expensive equipment is required and expensive.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing conductive fine particles of various particle diameters, which have good conductivity and are stable against environmental changes.

[0006]

That is, the present invention provides:

[0007]

Embedded image (Wherein R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or Represents an arylamino group or a substituent having a molecular weight of 100 or more substituted with an arylamino group, and X represents an NH group, a sulfur atom or an oxygen atom.

[0008]

Embedded image (Wherein R ₃ and R ₄ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or X represents an NH group, a sulfur atom or an oxygen atom.) The present invention provides a method for producing conductive fine particles, which comprises oxidatively polymerizing a conductive monomer represented by the formula:

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The compound used for producing the desired conductive fine particles has the general formula (I)

[0010]

Embedded image (R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom,
A hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or an arylamino group or a substituent having a molecular weight of 100 or more substituted with Express. X represents an NH group, a sulfur atom or an oxygen atom. ). Specifically, R ₁ and R ₂ represent a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group,
n-butyl group, sec-butyl group, tert-butyl group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, phenyl group, toluyl group, naphthyl group, phenoxy group, methylphenoxy group ,
A naphthoxy group, an amino group, a dimethylamino group, a diethylamino group, a phenylamino group, a diphenylamino group, a methylphenylamino group, a phenylbutylamino group, or a substituent having a molecular weight of 100 or more substituted with any of these.

More preferably, _one of R ₁ and R ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group,
In an amino group, an alkylamino group, a heterocyclic group or an arylamino group, the molecular weight is 100 or less, and the other is

[0012]

Embedded image —CH ₂ O— (CH ₂ CH ₂ O) _n —R ₅ n =
An integer of 5 to 100,000 is preferred. Here, R ₅ represents a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxy group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or an arylamino group. X is preferably a sulfur atom, that is, a thiophene derivative.

In the above formula, when n is less than 5, the particle size distribution of the obtained conductive fine particles becomes broad or massive, and n
If it exceeds 100,000, the solubility in a solvent becomes poor, which is not preferable. Although it is affected by the solvent, temperature and the like in the reaction, if n is approximately 10,000 or less, the average particle diameter of the obtained conductive fine particles is 200 nm or less, and n is 1 or less.
If it is between 0000 and 50,000, the average particle size of the obtained conductive fine particles will be 100 nm to 500 nm, and the particle size of the obtained conductive fine particles will increase as n increases. Preferably, n is from 50 to 100,000.

The amount of the compound (I) to be used is 10 to 500 parts by weight, preferably 20 to 400 parts by weight, based on 100 parts by weight of the conductive monomer (II). If the amount is less than 10 parts by weight, the effect of controlling the particle size is small, and if it is more than 500 parts by weight, no particularly advantageous effect is obtained, which is disadvantageous in cost.

The conductive monomers used in the present invention are represented by the general formula (II):

[0016]

Embedded image (Wherein R ₃ and R ₄ are each independently a hydrogen atom,
Represents a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or an arylamino group. X represents an NH group, a sulfur atom or an oxygen atom. ). Specifically, R ₃ and R ₄ are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, methoxy, ethoxy, n-propoxy. ,
Isopropoxy group, n-butoxy group, phenyl group, toluyl group, naphthyl group, phenoxy group, methylphenoxy group, naphthoxy group, amino group, dimethylamino group, diethylamino group, phenylamino group, diphenylamino group, methylphenylamino group Represents a phenylbutylamino group.

In the present invention, X in the general formula (II) is NH
The group, ie the pyrrole derivative, is preferred. Specifically, pyrrole, 3-methylpyrrole, 3,4-dimethylpyrrole, 3-ethylpyrrole, 3,4-diethylpyrrole, 3-n-propylpyrrole, 3-iso-propylpyrrole, 3-n-butyl Pyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-n-propoxypyrrole, 3-n-butoxypyrrole, 3-phenylpyrrole, 3-toluylpyrrole, 3-naphthylpyrrole, 3-phenoxypyrrole, 3-methylphenoxy Pyrrole, 3-naphthoxypyrrole, 3-aminopyrrole, 3-dimethylaminopyrrole, 3-diethylaminopyrrole, 3-diphenylaminopyrrole, 3-methylphenylaminopyrrole, 3-phenylnaphthinoaminopyrrole, and mixtures thereof. No. Of these, pyrrole is particularly preferred.

The oxidizing agent used in the present invention includes:
Inorganic acids, metal compounds and the like are effective, and specific examples of inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, chlorosulfonic acid and the like. As the metal compound, a compound known as a Lewis acid is preferably used, and aluminum, tin, titanium, zirconium, chromium, manganese, iron, copper, molybdenum, tungsten, ruthenium, palladium, metal chlorides such as platinum, inorganic and Specific examples include organic sulfates and sulfonates, nitrates, and acetylacetate compounds.

Oxides such as manganese dioxide and lead dioxide; peroxoacids such as ammonium persulfate, potassium persulfate and hydrogen peroxide; halogens such as iodine and bromine; organic compounds such as benzoquinone and diazonium salts can also be used. .

These oxidizing agents can be used in combination with inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as alkylbenzenesulfonic acid and alkylnaphthalenesulfonic acid. These oxidizing agents can be used as a mixture of two or more kinds. Of these, metal compounds are preferred, and ferric salts are particularly preferred. The amount of oxidizer used is
It is 0.5 to 10 mol, preferably 1 to 5 mol, per 1 mol of the conductive monomer.

In the present invention, a dispersant or the like may be used during the polymerization reaction. The preferred dispersant is not particularly limited, but specifically, polyvinyl alcohol, polyethylene oxide, polyacrylamide, sodium polyacrylate, polyvinylpyrrolidone, polycaprolactam, methyl methacrylate, vinyl acetate, celluloses, maleic acid resin, diene-based polymer Coalescing, acrylic polymers, melamine resins, urea resins, polyurethane resins, polymethyl methacrylates, unsaturated polyester resins, polyvinyl butyral, alkyd resins, and other high molecular resins or various surfactants. Used in combination of more than one species. The amount of these dispersants used is 1 to 500 parts by weight per 100 parts by weight of the conductive monomer,
Preferably it is 2 to 400 parts by weight. If it is less than 1 part by weight, the dispersing effect is small, and if it is more than 500 parts by weight, no particularly advantageous effect is obtained, which is disadvantageous in cost.

The concentration of the conductive monomer used in the reaction is usually 0.2 to 15% by weight, preferably 0.1% by weight, based on the solvent.
5 to 10% by weight.

The reaction is usually carried out by mixing a compound represented by the general formula (I), a monomer represented by the general formula (II), and an oxidizing agent in a solvent. Specifically, there are the following two types. 1. The monomer (II) is allowed to act after the oxidizing agent and the compound (I) coexist. 2. The oxidizing agent is allowed to act after coexistence of the monomer (II) and the compound (I).

The solvent used in the reaction may be any solvent, for example, water, alcoholic solvents such as methanol and ethanol,
Common organic solvents such as tetrahydrofuran, dioxane, benzene, toluene, dichloromethane and the like can be used. Preferably, it is water or a mixed solvent of water and a solvent soluble in water. The reaction temperature is from -30C to 70C, preferably from -10C to 50C. The reaction time is related to the reaction temperature, but is usually 0.5 to 200 hours, preferably 1 to 100 hours.

The reaction product is a dark brown to black solvent dispersion. The conductive polymer dispersion of the present invention may be purified and used by dialysis, ultrafiltration, filtration, centrifugation or the like.
Further, when used as a conductive polymer material of solid fine particles, the purified dispersion may be dried.

The conductive polymer dispersion of the present invention may be used after being coated by a known method such as dip coating, roller coating, bar coating, spin coating, curtain coating, etc. It may be used by impregnating it with the like. The conductive polymer material of the present invention can be used as it is as a conductive powder or mixed with a resin.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 A 300 ml flask was charged with 70 ml of purified water and 30 ml of methanol, and 0.5 g of a thiophene derivative having the following structure and 10 g of ferric chloride hexahydrate were prepared.
Was added and dissolved.

[0029]

Embedded image

Next, 1 g of pyrrole was added while stirring,
The mixture was stirred for 24 hours (reaction temperature: 10 ° C.).

<Example 2> 100 ml of purified water was placed in a 300 ml flask, and a thiophene derivative having the following structure was prepared.
4 g and 10 g of ferric chloride hexahydrate were added and dissolved.

[0032]

Embedded image

Next, 1 g of pyrrole was added with stirring,
The mixture was stirred for 24 hours (reaction temperature: 20 ° C.).

<Example 3> In Example 2, except that n of the thiophene derivative was changed from 8-9 to 12-13.
All were reacted under the same conditions.

Example 4 A reaction was carried out in the same manner as in Example 2 except that pyrrole was changed to 3-methylpyrrole.

<Example 5> In Example 2, except that 1.0 g of a thiophene derivative having an n of about 23000 to 46000 (molecular weight of 1,000,000 to 2,000,000) was used.
All were reacted in the same manner.

<Example 6> In Example 2, except that 1.0 g of a thiophene derivative having an n of about 46,000 to 69000 (molecular weight of 2,000,000 to 3,000,000) was used.
All were reacted in the same manner.

<Example 7> In Example 2, except that 1.0 g of a thiophene derivative having n of about 69000 to 92000 (molecular weight of 3,000,000 to 4,000,000) was used.
All were reacted in the same manner.

Example 8 The reaction was carried out in the same manner as in Example 2 except that the thiophene derivative was changed to 1.0 g of a pyrrole derivative having the following structure.

[0040]

Embedded image

Example 9 The reaction was carried out in the same manner as in Example 2 except that the thiophene derivative was changed to 1.2 g of a furan derivative having the following structure.

[0042]

Embedded image

Example 10 A 300 ml flask was charged with 100 ml of acetonitrile, and 0.6 g of the thiophene derivative of Example 6, 10 g of ferric chloride hexahydrate, and 0.5 g of polyvinylpyrrolidone as a dispersant were added and dissolved. Was. Next, 1 g of thiophene was added with stirring, followed by stirring for 24 hours (reaction temperature: 25 ° C.).

Example 11 A 300 ml flask was charged with 100 ml of acetonitrile, and 0.5 g of the pyrrole derivative of Example 8 and 10 g of ferric chloride hexahydrate were added and dissolved. Then add 1 g of thiophene with stirring,
The mixture was stirred for 24 hours (reaction temperature: 25 ° C.).

Comparative Example 1 The reaction was carried out in the same manner as in Example 1 except that no thiophene derivative was used.

Comparative Example 2 The reaction was carried out in the same manner as in Example 4 except that PEO-3 (polyethylene oxide, molecular weight: 600,000 to 1.1 million, manufactured by Sumitomo Seika Co., Ltd.) was used instead of the thiophene derivative. .

<Comparative Example 3> In Example 4, GL-03 (polyvinyl alcohol having a polymerization degree of 300, manufactured by Nippon Synthetic Chemical Co., Ltd.) was used instead of the thiophene derivative.
All were reacted in the same manner.

(Evaluation) The obtained various particle dispersions were settled by centrifugation, and washing by removing the supernatant was repeated three times. Further, vacuum drying was performed at 30 ° C. to obtain a black fine powder. This fine powder was observed with an electron microscope, and the average particle size was measured.

Further, after finely pulverizing the fine powder sufficiently in a mortar, about 0.1 g is put into a molding machine having a diameter of 1 cm, and
Pressure was applied at a pressure of 00 kg to produce a disc-shaped pellet. The pellet is measured with a 4-probe resistivity meter: LORESTA SP
The volume resistivity (Ω · cm) was measured with (manufactured by Mitsubishi Chemical Corporation). After the volume resistivity was measured, the pellets were used.
After being left for 30 days in an environment of 5 ° C. and 80%, the volume resistivity was measured in the same manner. Table 1 shows the results.

[0050]

[Table 1]

[0051]

According to the present invention, it is possible to obtain a conductive fine particle polymer which has good conductivity and is stable with respect to environmental changes. Also, since the particle size can be controlled, particles can be easily prepared according to the application such as an electronic element to be used.

Claims (2)

[Claims] [Claim 1] (Wherein R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or Represents an arylamino group or a substituent having a molecular weight of 100 or more substituted with an arylamino group, and X represents an NH group, a sulfur atom or an oxygen atom. (Wherein R ₃ and R ₄ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or X represents an NH group, a sulfur atom or an oxygen atom.) A method for producing conductive fine particles, comprising oxidatively polymerizing a conductive monomer represented by the formula: 2. In the formula (I), one of R ₁ and R ₂ is a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group, an alkoxyl group, an aryl group, an allyloxy group, an amino group, an alkyl group. amino group, and a molecular weight of 100 or less in a heterocyclic group or an arylamino group, the other is, embedded image _{-CH 2 O- (CH 2 CH 2} O) n -R 5 n =
An integer of _{5 to} 100,000 (R ₅ is a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group,
Represents a cyano group, an alkyl group, an alkoxy group, an aryl group, an allyloxy group, an amino group, an alkylamino group, a heterocyclic group or an arylamino group. The method according to claim 1, wherein X is a thiophene derivative represented by a sulfur atom.