JPH07118370A - Fine pyrrole polymer particle and production thereof - Google Patents

Abstract

PURPOSE:To obtain the fine polymer particles having a small average particle diameter, a narrow particle size distribution, and high conductivity by reacting a pyrrole compound with a water-soluble polymer having an amide bond and an oxidizing agent without using an organic solvent. CONSTITUTION:A mixture consisting of a pyrrole compound (a) represented by the formula (wherein R<1> and R<2> each independently is H, an alkyl, an alkoxy, an aryl, an aryloxy, amino, an alkylamino, or an arylamino and R<3> is H, an alkyl, or an aryl) and having no substituents at the 2- and 5-positions of the pyrrole ring, a water-soluble polymer (b) having an amide bond and a mol.wt. of 5,000-3,000,000, and as a polymerization catalyst at least one oxidizing agent (c) selected from inorganic acids and metallic Lewis acids is added to an aqueous solvent in an amount of 0.2-10wt.% based on the solvent, the amount of the ingredient (b) being 5-45 pts.wt. per 100 pts.wt. the ingredient (a) and that of the ingredient (c) being 0.5-10mol per/mol of the ingredient (a). The reactants are then reacted at -10 to 70 deg.C with stirring to obtain the particles having an average particle diameter of 0.2-10mum and a geometrical standard deviation of 1.1-1.6.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to fine particles of a pyrrole polymer which is an organic conductive polymer.

[0002]

2. Description of the Related Art Polyacetylene, polyparaphenylene, polyaniline, polypyrrole and the like are known as conductive polymers. These electrically conductive polymers are obtained in the form of powder, granules, lumps, or films, and their application to antistatic materials, electromagnetic wave shielding materials, and various electronic elements is being studied as they are or after molding depending on the application. Among these conductive polymers, polypyrrole is characterized by excellent stability in air and easy handling,
Research is ongoing. For example, it is known that when pyrrole is polymerized in water using ferric chloride as a catalyst, a black powdery polypyrrole having chlorine anion contained as a dopant and having conductivity is obtained. (Synthetic
Metals, 20 (1987) 365-371). But,
This product is a powder of several tens to 100 μm and is an aggregate of polypyrrole particles. Therefore, the molding process is difficult, the density of the molded product is small, and the electrical characteristics are insufficient.

A method is known in which the polymerization of pyrrole is carried out in a mixed solvent of water and an organic solvent compatible with water, using a specific oxidant as a catalyst. (JP-A-60-223854,
JP-A-63-69823). Since these use a mixed solvent of water and an organic solvent as a polymerization solvent, there are problems in recovering the organic solvent and treating wastewater. Further, there is a problem that polypyrrole becomes a mixture with another polymer or an inorganic compound used in the polymerization reaction. Further, a method of polymerizing pyrrole with ferric chloride in the presence of a water-soluble polymer, and adding an alkali after the polymerization to oxidize iron ions (JP-A-3-
100043) had a problem that iron oxide was mixed with polypyrrole.

Japanese Unexamined Patent Publication (Kokai) No. 3-730 discloses a method for producing an aqueous polypyrrole dispersion by oxidative polymerization of pyrrole in the presence of cellulose, polyvinylpyrrolidone or the like. This aqueous dispersion is used as it is by coating it on a base material as a paint, and the diameter of fine particles of the obtained pyrrole polymer is as small as 60 to 150 nm. Therefore, from the polymer mixture, the reduced oxidant,
It was difficult to wash and remove the by-produced acid and impurities such as unreacted oxidizing agent and monomer by an industrially easy method such as filtration and centrifugation. The amount of dextran or polyvinylpyrrolidone used is as large as 50 parts by weight based on 100 monomers of the polymer. For this reason, the one coated and dried as it was had insufficient conductivity.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for producing pyrrole polymer fine particles having a small average particle diameter, a uniform particle diameter, and high electric conductivity, without using an organic solvent. It is a thing.

[0006]

That is, the present invention has an average particle size of 0.2 to 10 μm and a geometric standard deviation of 1.1.
The present invention provides pyrrole polymer fine particles having a particle size of 1.6. In the present invention, 100 parts by weight of a pyrrole compound, 5 to 45 parts by weight of an amide bond-containing water-soluble polymer and an oxidizing agent as a polymerization catalyst are reacted in an aqueous solvent.
The average particle size is 0.2 to 10 μm, and the geometric standard deviation is 1.
The present invention provides a method for producing fine particles of a pyrrole-based polymer, which is characterized by having a particle size of 1 to 1.6. In particular, the present invention is
It is preferable to add the oxidant aqueous solution at once to the aqueous solution in which the pyrrole compound and the amide bond-containing water-soluble polymer are dissolved, and to react them.

The pyrroles used in the present invention have the general formula: (R ¹ ) (R ² ) C ₅ H ₂ N (R ³ ) (1) (wherein R ¹ and R ² are the same or different) And differently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, an alkylamino group or an arylamino group, and R ³ represents a hydrogen atom, an alkyl group or an aryl group. Compounds that can be mentioned. Among the pyrrole-based compounds represented by the general formula (1), a pyrrole-based compound having no substituent at the 2,5 position of the pyrrole ring skeleton structure is preferable.

More specifically, R ¹ and R ² are a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group,
n-butyl group, isobutyl group, sec-butyl group, te
rt-butyl group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, phenyl group, toluyl group, naphthyl group, phenoxy group, methylphenoxy group, naphthoxy group, amino group, dimethylamino group , A diethylamino group, an phenylamino group, a diphenylamino group, a methylphenylamino group, a phenylbutylamino group, R ³ is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,
It represents an isobutyl group, a sec-butyl group, a tert-butyl group, a phenyl group, a toluyl group, and a naphthyl group.

As the pyrrole compound, specifically,
Pyrrole, N-methylpyrrole, N-ethylpyrrole,
N-phenylpyrrole, N-naphthylpyrrole, N-methyl-3methylpyrrole, N-methyl-3ethylpyrrole, N-phenyl-3methylpyrrole, N-phenyl-3ethylpyrrole, 3-methylpyrrole, 3- Ethylpyrrole, 3-n-propylpyrrole, 3-iso-propylpyrrole, 3-n-butylpyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-n-propoxypyrrole, 3-n-butoxypyrrole, 3- Phenylpyrrole, 3-toluylpyrrole, 3-naphthylpyrrole, 3-phenoxypyrrole, 3-methylphenoxypyrrole, 3-naphthoxythiophene, 3-aminopyrrole, 3-dimethylaminopyrrole, 3-diethylaminopyrrole, 3-diphenylamino Pyrrole, 3-methylphenylaminopyr Lumpur, etc. and mixtures thereof 3-phenyl naphthyl amino pyrrole and the like. Of these, pyrrole is particularly preferable. A small amount of a monomer that can be polymerized under the polymerization conditions of the present invention, for example, aniline, may be mixed with the pyrrole-based compound and copolymerized.

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

Further, oxides such as manganese dioxide and lead dioxide, peroxo acids 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. . Further, these oxidizing agents can be used in combination with an inorganic acid such as sulfuric acid, hydrochloric acid or nitric acid or an organic acid such as alkylbenzene sulfonic acid or alkylnaphthalene sulfonic acid.

It is also possible to use a mixture of two or more of these oxidizing agents. Of these, metal compounds are preferable, and ferric salts are particularly preferable. The amount of the oxidizing agent used is 0.5 to 10 mol, preferably 1 to 5 mol, per 1 mol of the pyrrole compound. As the amide bond-containing polymer used in the present invention, polyvinylpyrrolidone, vinylpyrrolidone copolymer containing 50% or more of vinylpyrrolidone, poly-2-oxazoline, poly-2-methyl-
2-oxazoline, poly-2-ethyl 2-oxazoline and the like can be mentioned. Of these, polyvinylpyrrolidone is particularly preferable because it has good dispersion stability.

The amide bond-containing polymer may have a molecular weight of 5,000 to 3,000,000. Preferably used is 20,000 to 2,000,000. When the molecular weight is below this range, the particle size distribution of the obtained pyrrole polymer is large, which is not preferable. Further, if it exceeds this range, the solubility in water becomes poor.

The amount of the amide bond-containing polymer used is 5 to 45 parts by weight, preferably 7 to 30 parts by weight, based on 100 parts of the pyrrole compound. If it is less than 5 parts by weight, the effect of controlling the particle size is small, and if it is more than 45 parts by weight, the particle size of the polymer becomes small. The reaction is usually carried out using water as a solvent, but in some cases, a small amount of a water-soluble organic solvent may be added to carry out the reaction. The concentration of the pyrrole compound used in the reaction is usually 0.2 to 10% by weight, preferably 0.5 to 5% by weight, based on the aqueous solvent.

The reaction is usually carried out by mixing an aqueous solution of a polymer containing an amide bond with a pyrrole compound dissolved therein and an aqueous solution of an oxidant. When the aqueous solution in which the amide bond-containing polymer and the pyrrole compound are dissolved and the aqueous solution of the oxidizing agent are mixed, it is preferable to add the latter to the former while sufficiently stirring the former. In particular, it is preferable to add the latter to the former all at once with vigorous stirring. The reverse addition is not preferable because the particle size distribution becomes large. When the oxidizing agent aqueous solution is gradually added to the reaction system, the resulting polymer has a large particle size distribution, which is not preferable. The reaction temperature is -10 to 70 ° C, preferably 0 to 40
℃.

After the reaction, the reaction mixture is purified by washing with water containing a dispersion stabilizer as washing water and filtering or centrifuging. An aqueous solution of polyvinylpyrrolidone is usually used as the dispersion stabilizer. The reaction mixture after the reaction and the dispersion liquid re-dispersed with an aqueous solution of polyvinylpyrrolidone after purification are both stable. The pyrrole polymer particles thus obtained have an average particle diameter of 0.2 to 10 μm, preferably 0.2.
5 to 2 μm, more preferably 0.3 to 1 μm, and its geometric standard deviation is 1.1 to 1.6, preferably 1.2 to 1.
5, more preferably 1.2 to 1.4.

The geometric standard deviation (σg) used in the present invention is
The diameter corresponding to the cumulative probability of the number distribution of 50%: d ₅₀ % (called the number median diameter. In the present invention, this value was used as the average particle diameter), and the diameter corresponding to the cumulative probability of 84%: d ₈₄ %. At this time, σg = d ₈₄ % / d ₅₀ %. (See William C. Hines, Kazuya Hayakawa, Aerosol Technology, 1985, Inoue Shoin, pages 85-89).

The pyrrole polymer fine particles of the present invention can be used as a conductive powder as it is or as a mixture with rubber or plastic. Further, it can be used as an aqueous dispersion as it is or as a mixture with a latex or emulsion which is an aqueous dispersion of a polymer substance. In addition, the aqueous dispersion is made of plastic, rubber, paper,
Conductivity can be imparted by forming a coating film on the surface of cloth, film, metal or the like, and it can be used in a wide range requiring conductivity.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 20 g of purified water was put in a glass container and the molecular weight was 40,000.
Add 0.050 g of polyvinylpyrrolidone powder of 0,
Dissolve. After adding 0.24 g of pyrrole and stirring to dissolve it, 2.34 g of ferric chloride hexahydrate was added to purified water 5
The solution dissolved in g was added at once, and the mixture was polymerized at 20 ° C. for 3 hours while stirring vigorously. After the polymerization, a part of the reaction liquid was dissolved in a small amount of polyvinylpyrrolidone, and 50 ml of water was used.
In addition, the particle size and the number distribution of the produced polypyrrole were measured using a laser diffraction particle size distribution analyzer (SALD-1100 manufactured by Shimadzu Corporation). The average particle diameter (the median number diameter was used as the average particle diameter) was 0.43 μm,
The geometric standard deviation (σg) was 1.32. The reaction mixture was washed and purified by centrifugation, and then vacuum dried at 50 ° C. for 8 hours to obtain a pyrrole polymer in an amount of 0.26 g.

Example 2 The procedure of Example 1 was repeated except that 0.021 g of polyvinylpyrrolidone having a molecular weight of 1.2 million was used. The average particle size of the produced pyrrole polymer is 0.3.
6 μm, geometric standard deviation of 1.25, polymer yield of 0.
It was 26 g.

Example 3 21 g of purified water was placed in a glass container and the molecular weight was 40,000.
Add 0.045 g of 0 polyvinylpyrrolidone powder,
Dissolved. Pyrrole (0.24 g) was added, and the mixture was stirred and dissolved, and then ferric sulfate hydrate (Fe ₂ (SO ₄ ) ₃ 8.3H ₂ O) 4.
A solution prepared by dissolving 0 g in 8 g of purified water was added at once and polymerized at 20 ° C. for 3 hours while stirring vigorously. The obtained polypyrrole had an average particle size of 0.37 μm, a geometric standard deviation of 1.32, and a polypyrrole yield of 0.28 g.

Example 4 21 g of purified water was placed in a glass container and the molecular weight was 40,000.
Add 0.060 g of 0 polyvinylpyrrolidone powder,
Dissolve. After adding 0.24 g of pyrrole and stirring to dissolve it, a solution of 4 g of ferric nitrate nonahydrate dissolved in 4 g of purified water was added all at once and stirred for 20 minutes.
Polymerization was carried out at ℃ for 3 hours. The obtained pyrrole polymer had an average particle size of 0.38 μm, a geometric standard deviation of 1.30, and a polymer yield of 0.26 g.

Example 5 In a glass container, 168 g of purified water and 0.36 g of polyvinylpyrrolidone powder having a molecular weight of 40,000 were added and dissolved. After adding 1.92 g of pyrrole and stirring to dissolve it, 32 g of the same ferric sulfate hydrate as in Example 1 was added to purified water 3
A solution dissolved in 2 g was added at once, and the reaction was carried out at 20 ° C. for 3 hours with vigorous stirring. The purified polypyrrole had an average particle size of 0.45 μm and a geometric standard deviation of 1.22. A part of this reaction solution was taken, allowed to stand at room temperature for 1 month and then measured again. As a result, the average particle size was 0.44 μm and the geometric standard deviation was 1.24.

A portion of the reaction solution was taken and used as a cleaning solution in an amount of 0.18% of polyvinylpyrrolidone having a molecular weight of 40,000.
It was centrifuged using an aqueous solution. The first separated liquid obtained by centrifuging the reaction liquid was yellow and transparent and had a PH of 1 or less.
After centrifugation 4 times, the separated liquid became clear and PH was 3
Became 4. Precipitation 0.18% molecular weight 40,000
After being redispersed in an aqueous solution of polyvinylpyrrolidone of about the same concentration as at the time of polymerization, the particle size was measured, and as a result, the average particle size was 0.42 μm and the geometric standard deviation was 1.33. After leaving this dispersion at room temperature for 1 month, the particle size was measured again,
The average particle size was 0.46 μm, and the geometric standard deviation was 1.30.

Example 6 The reaction solution of Example 5 was put into a filter and filtered under pressure using a 0.2 μm membrane filter. As a result, the filtrate was yellow and transparent and PH was 1 or less. There wasn't. The polymer on the filter paper was washed with an aqueous solution of 0.18% polyvinylpyrrolidone and filtered under pressure. Do this operation 3
As a result of repeating the process repeatedly, the polymer did not flow out, the filtrate was colorless and transparent, and its PH was 3 to 4. The polymer was again dispersed in a 0.18% polyvinylpyrrolidone aqueous solution to prepare a dispersion, and the particle size distribution thereof was measured. The average particle size was 0.50 μm, and the geometric standard deviation was 1.26.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that 0.12 g of polyvinylpyrrolidone was used in Example 1. The average particle size of the obtained polypyrrole was 0.1 μm or less. Comparative Example 2 In Example 2, 0.015 g of polyvinylpyrrolidone
Polymerization was performed in the same manner as in Example 2 except that was used. The average particle size of the obtained polypyrrole was 30 μm or more.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 3 except that 0.12 g of polyvinylpyrrolidone was used. The average particle size of the obtained polypyrrole was 0.1 μm or less.

Comparative Example 4 Polymerization was carried out in the same manner as in Example 3 except that 0.12 g of polyvinylpyrrolidone was used in Example 4. The average particle size of the obtained polypyrrole was 0.1 μm or less.

Comparative Example 5 In Example 1, pyrrole was added to an aqueous solution containing polyvinylpyrrolidone and ferric chloride for polymerization. The obtained polypyrrole had an average particle size of 0.67 μm and a geometric standard deviation of 1.97.

Comparative Example 6 An experiment was conducted in exactly the same manner as in Example 3, except that the aqueous ferric sulfate solution was added dropwise over 2 minutes instead of being added all at once in Example 3. The produced polypyrrole had an average particle size of 0.33 μm and a geometric standard deviation of 1.88.

[0031]

According to the present invention, by polymerizing a pyrrole-based compound in an aqueous solution of an amide bond-containing water-soluble polymer, the average particle size is easily treated such as filtration in the range of 0.2 to 1
Since the particle size distribution is 0 μm and the particle size distribution is relatively narrow, it is possible to obtain organic conductive fine particles suitable as a coating material or a conductive filler.

Claims (2)

[Claims] 1. Pyrrole polymer fine particles having an average particle size of 0.2 to 10 μm and a geometric standard deviation of 1.1 to 1.6. 2. 100 parts by weight of a pyrrole compound, 5 to 45 parts by weight of an amide bond-containing water-soluble polymer, and an oxidizing agent as a polymerization catalyst are reacted in an aqueous solvent to give an average particle size of 0.2 to 10 μm and its geometry. Standard deviation is 1.1 to 1.6
And a method for producing fine particles of a pyrrole polymer.