JP5206922B2 - Polypyrrole fine particle dispersion - Google Patents

Description

  The present invention relates to a dispersion liquid comprising polypyrrole fine particles nano-dispersed in a medium containing a low-volatile organic solvent as a main component.

  A method for producing polypyrrole fine particles comprising pyrrole and / or a pyrrole derivative nano-dispersed in an organic solvent is disclosed in JP-A-2005-314538. Here, the organic solvent, water, an anionic surfactant, A method for producing finely divided polypyrrole fine particles nano-dispersed in an organic solvent by adding a monomer of pyrrole and / or a pyrrole derivative to an O / W type emulsion obtained by mixing and stirring the pyrrole and oxidatively polymerizing the monomer Has been.

The organic solvent used in the dispersion of the polypyrrole fine particles produced by this production method has been limited to some aromatic hydrocarbon solvents such as toluene, xylene and benzene. When a coating layer of 100 nm is formed using a dispersion of polypyrrole fine particles using these solvents as a coating material, the conductivity is reduced only to about 10 ⁸ Ω, and the adhesion to the substrate is improved. For the purpose, when a binder is added to the paint, the formed coating layer has a problem that the resistance value is remarkably increased.
JP 2005-314538 A

  An object of the present invention is to provide a polypyrrole fine particle dispersion that can solve the problems of the conventional polypyrrole fine particle dispersion disclosed in, for example, JP-A-2005-314538.

  As a result of intensive studies to solve the above problems, the present inventors have found that some highly volatile aromatic hydrocarbon solvents such as toluene, xylene, benzene and the like are not mainly dispersions but low volatile organic compounds. When a coating liquid layer is formed by using the dispersion liquid as a coating material when the composition ratio of the low-volatile organic solvent is 80% or more, the dispersion liquid is mainly composed of a solvent. The layer has excellent conductivity (shows a low resistance value), the change in conductivity with time is extremely small, and the use of a binder does not significantly increase the resistance value, thus completing the present invention. It was.

That is, the present invention
1. A dispersion in which polypyrrole fine particles are dispersed in an organic medium,
The organic medium is composed of one kind or two or more kinds of organic solvents that do not cause layer separation, and at least one kind of low-volatile organic solvent having a volatilization rate of 10 or less when the volatilization rate of butyl acetate is 100. A dispersion containing 80% or more of
2. The organic medium contains at least one organic solvent having a solubility in water of 1% or less. The described dispersion,
3. The organic medium has at least one highly volatile organic solvent having a solubility in water of 1% or less and a volatilization rate greater than 10 when the volatilization rate of butyl acetate is 100. 1 characterized by the above. Or 2. The described dispersion,
4). The organic medium does not contain a highly volatile organic solvent having a volatilization rate higher than 10 when the volatilization rate of butyl acetate is 100. Or 2. 4. The dispersion described The low-volatile organic solvent is a terpentine organic solvent. Or 4. A dispersion according to any one of
6). The average particle size of the pyrrole fine particles is in the range of 10 to 100 nm. Or 5. A dispersion according to any one of
It is about.

  When the dispersion in which the polypyrrole fine particles are dispersed in the organic medium of the present invention contains at least one low-volatile organic solvent in an amount of 80% or more, when the coating layer is formed using the dispersion as a paint, The formed coating layer has excellent conductivity (shows a low resistance value), extremely little change in conductivity over time, and excellent effect that the resistance value does not increase remarkably even when a binder is used. Play.

The reason why the excellent effect as described above is exerted by using a dispersion containing at least 80% of at least one low-volatile organic solvent is considered as follows.
When a coating layer is formed using a dispersion of polypyrrole fine particles mainly composed of an aromatic hydrocarbon solvent such as toluene, xylene, benzene, etc., as the aromatic hydrocarbon solvent is highly volatile. As shown in FIG. 1, the polypyrrole fine particles 3 are uniformly dispersed in the coating layer 2 formed on the substrate 1.
On the other hand, when the coating layer is formed using a dispersion of polypyrrole fine particles mainly composed of a low-volatile organic solvent as a coating material, the low-volatile organic solvent is low-volatile, so it is difficult to volatilize, Therefore, since a certain amount of time is required until the film is formed, as shown in FIG. 2, the polypyrrole fine particles 3 having a small specific gravity are many in the upper half of the coating layer 2 formed on the substrate 1. (In the case of using a dispersion containing 80% or more of at least one low-volatile organic solvent, specifically, a structure in which 60% or more of polypyrrole is present in the upper half of the coating layer 2) ).

In this way, many polypyrrole fine particles 3 are present in the upper half of the coating layer 2, that is, many polypyrrole fine particles 3 are present near the surface of the coating layer 2. It improves (that is, the resistance value of the film surface decreases), and the polypyrrole fine particles 3 existing on the bonding surface of the substrate 1 and the coating layer 2 are reduced, so that the bonding between the substrate 1 and the coating layer 2 is performed. Will be improved.
In particular, when a binder is added for the purpose of improving the adhesion to the substrate, a large amount of the polypyrrole fine particles 3 are present in the upper half of the coating layer 2, so that a large amount of the binder is present in the lower half of the coating layer 2. As a result, in addition to further improving the adhesiveness with the base material, the conductivity is hardly lowered. And it becomes possible to increase the quantity of the binder added by this, and can further improve the coating-film intensity | strength and transparency improvement.

As described above, the coating layer formed by using the polypyrrole fine particle dispersion of the present invention reduces the resistance value of the film surface due to the presence of many polypyrrole fine particles 3 near the surface thereof. A lower resistance value can be achieved as compared with the amount of the fine particles 3, so that excellent conductivity can be maintained even with a small amount of polypyrrole fine particles.
Moreover, the coating layer formed using the polypyrrole fine particle dispersion of the present invention has a very small change in conductivity over time.
Furthermore, the polypyrrole fine particle dispersion of the present invention is a result of using a low volatile organic solvent, resulting in a highly volatile organic solvent such as an inkjet method, a spray method, or a printing method (for example, aromatics such as toluene, xylene, benzene). It is possible to form a film by a coating method that was impossible when a dispersion of polypyrrole fine particles mainly containing a hydrocarbon solvent was used.

The present invention will be described in more detail.
The dispersion in which polypyrrole fine particles are dispersed in the organic medium of the present invention is composed of one or more organic solvents in which the organic medium does not cause layer separation, and the volatilization rate of butyl acetate is 1
It is a dispersion characterized by containing 80% or more of at least one kind of low-volatile organic solvent with a volatilization rate of 10 or less.

The polypyrrole fine particles used in the present invention can be produced, for example, by the production method shown below.
(1) A monomer of pyrrole and / or a pyrrole derivative is added to an O / W type emulsion obtained by mixing and stirring an organic solvent, water, and an anionic surfactant, and the monomer is oxidatively polymerized. Manufacturing method.
(2) Polymerization is initiated in an aqueous medium containing an amount of pyrrole and / or a pyrrole derivative, an anionic surfactant and / or a nonionic surfactant, and an oxidizing agent that can be solubilized in the aqueous medium, and the polymerization rate of polypyrrole The manufacturing method by adding an organic solvent to this polymerization system at the time when becomes 10 to 60% and further proceeding the polymerization.
The manufacturing conditions and operations of the manufacturing methods (1) and (2) will be described below.

Manufacturing method (1)
Examples of pyrrole and / or pyrrole derivative monomers that can be used in the production method (1) include pyrrole, N-methylpyrrole, N-ethylpyrrole, N-phenylpyrrole, N-naphthylpyrrole, and N-methyl-3-methylpyrrole. N-methyl-3-ethylpyrrole, N-phenyl-3-methylpyrrole, N-phenyl-3-ethylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-butylpyrrole, 3-methoxypyrrole, 3-ethoxypyrrole, 3-n-propoxypyrrole, 3-n-butoxypyrrole, 3-phenylpyrrole, 3-toluylpyrrole, 3-naphthylpyrrole, 3-phenoxypyrrole, 3-methylphenoxypyrrole, 3-aminopyrrole, 3-dimethylaminopyrrole, 3-diethylaminopyrrole, - diphenylamino pyrrole, 3-methylphenylamino pyrrole, 3-phenyl naphthyl amino pyrrole, and the like. Particularly preferred is pyrrole.

Various anionic surfactants used in the production method (1) can be used, but those having a plurality of hydrophobic ends (for example, those having a branched structure in a hydrophobic group or those having a plurality of hydrophobic groups). Is preferred. By using such an anionic surfactant having a plurality of hydrophobic ends, stable micelles can be formed.
Among anionic surfactants having multiple hydrophobic ends, di-2-ethylhexyl sodium sulfosuccinate (4 hydrophobic ends), di-2-ethyloctyl sodium sulfosuccinate (4 hydrophobic ends) and branched type Alkyl benzene sulfonate (two hydrophobic ends) can be preferably used.

  The amount of the anionic surfactant in the reaction system is preferably less than 0.2 mol, more preferably 0.05 mol to 0.15 mol, relative to 1 mol of the monomer of pyrrole and / or a pyrrole derivative. If the amount is less than 0.05 mol, the yield and the dispersion stability are lowered. On the other hand, if the amount is 0.2 mol or more, the resulting conductive fine particles may have a conductivity humidity dependency.

  In the production method (1), the organic solvent forming the organic phase of the emulsion has a solubility in water of 1% or less, and the volatilization rate when the volatilization rate of butyl acetate is 100 is high. Volatile organic solvent. Specifically, it is an aromatic hydrocarbon solvent such as toluene, xylene and benzene, but the highly volatile organic solvent can be used alone or as a mixture of two or more.

The ratio of the organic phase to the aqueous phase in the emulsion is preferably 75% by volume or more in the aqueous phase. When the water phase is 20% by volume or less, the amount of pyrrole monomer dissolved is reduced and the production efficiency is deteriorated.

  Examples of the oxidizing agent used in the production method (1) include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and chlorosulfonic acid, organic acids such as alkylbenzenesulfonic acid and alkylnaphthalenesulfonic acid, potassium persulfate and ammonium persulfate. And peroxides such as hydrogen peroxide can be used. These may be used alone or in combination of two or more. Polypyrrole can be polymerized even with a Lewis acid such as ferric chloride, but the produced particles may aggregate and the polypyrrole may not be finely dispersed. Particularly preferred oxidizing agents are persulfates such as ammonium persulfate.

  The amount of the oxidizing agent in the reaction system is preferably 0.1 mol or more and 0.8 mol or less, more preferably 0.2 to 0.6 mol with respect to 1 mol of pyrrole and / or pyrrole derivative monomer. . If the amount is less than 0.1 mol, the degree of polymerization of the monomer decreases, making it difficult to separate and collect the conductive fine particles. On the other hand, if the amount is 0.8 mol or more, the polypyrrole aggregates to increase the particle size of the conductive fine particles. Stability and transparency of the coating deteriorate.

The production method (1) is performed by, for example, the following steps:
(A) a step of preparing an emulsion by mixing and stirring an anionic surfactant, an organic solvent and water;
(B) a step of dispersing a monomer of pyrrole and / or a pyrrole derivative in an emulsion, (c) a step of oxidative polymerization of the monomer to cause polyanol to contact and adsorb on an anionic surfactant,
(D) A step of separating the organic phase and collecting the conductive fine particles.

  Each of the above steps can be performed using means known to those skilled in the art. For example, the mixing and stirring performed at the time of preparing the emulsion is not particularly limited. For example, a magnetic stirrer, a stirrer, a homogenizer, or the like can be selected as appropriate. The polymerization temperature is 0 to 25 ° C, preferably 20 ° C or less. If the polymerization temperature exceeds 25 ° C., side reactions occur, which is not preferable.

Manufacturing method (2)
Examples of pyrrole and / or pyrrole derivatives that can be used in the production method (2) include pyrrole, N-methylpyrrole, N-ethylpyrrole, N-phenylpyrrole, N-naphthylpyrrole, N-methyl-3-methylpyrrole, N -Methyl-3-ethylpyrrole, N-phenyl-3-methylpyrrole, N-phenyl-3-ethylpyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-butylpyrrole, 3-methoxypyrrole, 3- Ethoxypyrrole, 3-n-propoxypyrrole, 3-n-butoxypyrrole, 3-phenylpyrrole, 3-toluylpyrrole, 3-naphthylpyrrole, 3-phenoxypyrrole, 3-methylphenoxypyrrole, 3-aminopyrrole, 3- Dimethylaminopyrrole, 3-diethylaminopyrrole, 3-diphe Le aminopyrrole, 3-methylphenylamino pyrrole, 3-phenyl naphthyl amino pyrrole, and the like. Particularly preferred is pyrrole.

The amount of pyrrole and / or pyrrole derivative that can be solubilized in an aqueous medium is 80 g / L or less, particularly preferably 20 g / L to 1 g / L, relative to water.
When an amount of pyrrole and / or a pyrrole derivative that cannot be solubilized in an aqueous medium is added (a pyrrole and / or pyrrole derivative having a saturation concentration or more), a massive polypyrrole is generated immediately after the start of polymerization, and the desired fine particles are obtained. I can't. On the other hand, when the monomer of pyrrole and / or pyrrole derivative is 1 g / L or less, the polymerization reaction is extremely slow, and it takes a long time to obtain desired fine particles.

As the anionic surfactant that can be used in the production method (2), a commonly used anionic surfactant can be used, and it is not particularly limited, but one having a plurality of hydrophobic ends (for example, hydrophobic) Those having a branched structure in the group and those having a plurality of hydrophobic groups are preferred. By using such an anionic surfactant having a plurality of hydrophobic ends, stable micelles can be formed, and separation of the aqueous phase and the organic solvent phase after polymerization is easy. Conductive fine particles dispersed in are easily available. Among anionic surfactants having multiple hydrophobic ends, di-2-ethylhexyl sulfosuccinate (4 hydrophobic ends), di-2-octyl sodium sulfosuccinate (4 hydrophobic ends) and branched alkylbenzene sulfone Acid salts (two hydrophobic ends) can be preferably used.
Moreover, said anionic surfactant can be used individually or in mixture of 2 or more types.

Nonionic surfactants that can be used in the production method (2) include, for example, polyoxyethylene alkyl ethers, alkyl glucosides, fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxy Examples include ethylene fatty acid esters, fatty acid alkanolamides, and polyoxyethylene alkylphenyl ethers.
Said nonionic surfactant can be used individually or in mixture of 2 or more types.

  The amount of the anionic surfactant and / or nonionic surfactant used is preferably less than 0.2 mol, more preferably 0.05 mol to 0.15 mol, relative to 1 mol of the monomer of pyrrole and / or a pyrrole derivative. If the amount is less than 0.05 mol, the yield and the dispersion stability are lowered. On the other hand, if the amount is 0.2 mol or more, the resulting conductive fine particles may have a conductivity humidity dependency.

  Examples of the oxidizing agent used in the production method (2) include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and chlorosulfonic acid, organic acids such as alkylbenzenesulfonic acid and alkylnaphthalenesulfonic acid, potassium persulfate and ammonium persulfate. And peroxides such as hydrogen peroxide can be used. These may be used alone or in combination of two or more. Polypyrrole can be polymerized even with a Lewis acid such as ferric chloride, but the produced particles may aggregate and the polypyrrole may not be finely dispersed. Particularly preferred oxidizing agents are persulfates such as ammonium persulfate.

  The amount of the oxidizing agent to be used is preferably 0.1 mol or more and 0.8 mol or less, more preferably 0.2 to 0.6 mol, with respect to 1 mol of pyrrole and / or pyrrole derivative monomer. If the amount is less than 0.1 mol, the degree of polymerization of the monomer decreases, making it difficult to separate and collect the conductive fine particles. On the other hand, if the amount is 0.8 mol or more, the polypyrrole aggregates to increase the particle size of the conductive fine particles. Stability deteriorates.

The aqueous medium used in the production method (2) is basically water, and if desired, a dopant or the like can be added for the purpose of improving the conductivity of the formed polypyrrole fine particles and reducing the change with time of the conductivity. .
The amount of the aqueous medium to be used is an amount capable of solubilizing the pyrrole and / or pyrrole derivative to be used, that is, an amount such that the concentration of pyrrole and / or pyrrole derivative is 80 g / L or less as defined above. Particularly preferred is an amount of 20 g / L to 1 g / L.

As described above, in the production method (2), a dopant can be added.
In the polymerization in the O / W type emulsion described in JP-A-2005-314538, a dopant is not used, and therefore the conductivity of the obtained polypyrrole is not necessarily high, and changes with time are not observed. It was easy to receive.
In the production method (2), by adding a predetermined dopant to the aqueous medium, it may be possible to improve the conductivity and reduce the change with time.
The kind of the dopant when the dopant is used in the production method (2) is not particularly limited as long as it is soluble in the monomer of pyrrole and / or pyrrole derivative, and generally a polymer of pyrrole and / or pyrrole derivative is used. An acceptor dopant suitably used for the conductive fine particles can be used as appropriate. Typical examples thereof include polystyrene sulfonic acid, paratoluene sulfonic acid, methane sulfonic acid, trifluoromethane sulfonic acid, and anthraquinone sulfonic acid. Sulfonic acids such as benzenesulfonic acid, naphthalenesulfonic acid, sulfosalicylic acid, dodecylbenzenesulfonic acid and allylsulfonic acid, halogens such as perchloric acid, chlorine and bromine, Lewis acid and protonic acid. These may be in the acid form or in the salt form. Preferred from the viewpoint of solubility in monomers, tetrabutylammonium perchlorate, tetraethylammonium perchlorate, tetrabutylammonium tetrafluoroborate, tetrabutylammonium trifluoromethanesulfonate, tetrabutylammonium trifluorosulfonimide, dodecylbenzene Examples thereof include sulfonic acid and p-toluenesulfonic acid.

  When the dopant is used, the dopant is preferably used in an amount of 0.01 to 0.3 molecule of dopant per pyrrole polymer unit unit to be generated. When the amount is 0.01 molecule or less, the amount of dopant necessary to form a sufficient conductive path is insufficient, and it is difficult to obtain high conductivity. On the other hand, addition of 0.3 molecule or more does not improve the doping rate, so the addition of 0.3 molecule or more dopant is not economically preferable. Here, the pyrrole polymer unit unit refers to a repeating portion corresponding to one molecule of a pyrrole polymer monomer obtained by polymerizing a pyrrole monomer.

In the production method (2), after initiating polymerization in an aqueous medium containing an amount of pyrrole and / or a pyrrole derivative, an anionic surfactant and / or a nonionic surfactant, and an oxidizing agent that can be solubilized in the aqueous medium, An organic solvent is added when the polymerization rate of polypyrrole reaches 10 to 60%. More preferably, the organic solvent is added when the polymerization rate of the polypyrrole reaches 20 to 50%. When the organic solvent is added when the polymerization rate is less than 10%, the conjugated double bond of polypyrrole is not sufficiently grown, so that predetermined conductivity cannot be obtained. Further, the subsequent polymerization becomes extremely slow, and the separation of water and the organic solvent becomes extremely poor. On the contrary, when the organic solvent is added when the polymerization rate exceeds 60%, the size of the polypyrrole particles transferred to the organic solvent becomes large particles of several hundred nm or more, and the dispersion stability is also poor.
The polymerization rate can be easily calculated from the ratio of the initially added monomer amount and the residual monomer amount by measuring the residual monomer using gas chromatography.

The presence of a certain amount of residual monomer (unreacted monomer) in the reaction system is considered important in order not to make the particle size of the polypyrrole too large and to cause aggregation of the polypyrrole particles. Therefore, it is considered that when the polymerization rate is improved and the amount of the residual monomer is decreased, the particle size of the polypyrrole is suddenly increased and the polypyrrole particles are aggregated.
That is, in order not to make the particle size of polypyrrole too large and to cause aggregation of polypyrrole particles, the amount of residual monomer (unreacted monomer) in the reaction system is 40 to 90 of the amount of monomer initially added. It can be said that it is important to add an organic solvent at the time when% remains.
Similarly, the size of the fine particles dispersed in the aqueous medium at the time of adding the organic solvent is also extremely important. A graph showing the relationship between the polymerization rate (%) of polypyrrole in an aqueous medium and the average particle size (nm) of the resulting polypyrrole is shown in FIG. 3, from which the polymerization rate of polypyrrole exceeds a certain value. It can be seen that the average particle size of polypyrrole increases rapidly. Therefore, for example, even when an organic solvent is added when the average particle size of polypyrrole exceeds 100 nm, the size of the polypyrrole particles transferred to the organic solvent tends to be large particles of several hundred nm or more as a result. Dispersion stability tends to be poor.
Therefore, it is preferable to add the organic solvent when the particle size of the polypyrrole is 100 nm or less.
In addition, the average particle diameter of polypyrrole can be easily measured by a laser Doppler method.

The organic solvent to be added is not particularly limited as long as it is an organic solvent having a solubility in water of 1% or less. At least one high volatility in which the volatilization rate when the volatilization rate of butyl acetate is 100 is greater than 10. A low-volatile organic solvent or a mixture of the high-volatile organic solvent and the low-volatile organic solvent with a volatilization rate of 10 or less when the volatilization rate of the volatile organic solvent and butyl acetate is 100 Examples of the highly volatile organic solvent include aliphatic esters such as butyl acetate, aromatic solvents such as toluene, ketones such as methyl ethyl ketone, cyclic saturated hydrocarbons such as cyclohexane, and n-octane. Chain saturated hydrocarbons, chain saturated alcohols such as n-octanol, aromatic esters such as methyl benzoate, aliphatic ethers such as diethyl ether Examples of the low volatile organic solvent include mineral spirit, isoparaffin, turpentine oil, limonene of orange oil, P-menthane, α-pinene, β-pinene, terpinolene, isobornyl acetate, Examples include terpentine solvents such as terpinyl acetate, terpineol, α-terpineol, and dihydroterpineol, with terpentine solvents being preferred.
Moreover, limonene is preferable in that it is naturally derived and environmentally friendly.
The amount of the organic solvent to be used is preferably 5 to 40% (v / v), particularly preferably 10 to 25% (v / v) by volume with respect to the amount of water used in the polymerization reaction.
If it is less than 5% (v / v), the particle density becomes high and the dispersibility becomes poor, resulting in aggregation. When it exceeds 40% (v / v), the particle density becomes relatively low, so the repulsive force between the particles becomes small and dispersion cannot be maintained.

The method for producing the polypyrrole fine particles is performed, for example, in the following steps:
(A) a step of adding an anionic surfactant and / or a nonionic surfactant, a monomer of pyrrole and / or a pyrrole derivative and optionally a dopant to water and mixing and stirring;
(B) adding an oxidizing agent to start oxidative polymerization;
(C) adding an organic solvent when the polymerization rate becomes 10 to 60%,
(D) a step of mixing and stirring to further advance the polymerization reaction;
(E) A step of separating the organic phase and collecting polypyrrole fine particles nano-dispersed in the organic solvent layer.

  Each of the above steps can be performed using means known to those skilled in the art. For example, the mixing and stirring is not particularly limited. For example, a magnetic stirrer, a stirrer, a homogenizer, and the like can be selected as appropriate. The polymerization temperature is 0 to 25 ° C, preferably 20 ° C or less. If the polymerization temperature exceeds 25 ° C., side reactions occur, which is not preferable.

The polypyrrole fine particles nano-dispersed in the organic solvent layer obtained by the above production method (1) or the polypyrrole fine particles nano-dispersed in the organic solvent layer obtained by the above production method (2) are used as they are or as necessary. After being concentrated, the organic solvent is diluted with a low-volatile solvent that does not cause layer separation (the volatilization rate is 10 or less when the volatilization rate of butyl acetate is 100), and contains 80% or more of a low-volatile organic solvent. A dispersion in which polypyrrole fine particles are dispersed in the medium is obtained.
By the above operation, the dispersion liquid in which the polypyrrole fine particles are dispersed in the organic medium of the present invention is composed of one or more organic solvents that do not cause layer separation, and the volatilization rate of butyl acetate. 80% or more of at least one low-volatile organic solvent having a volatilization rate of 10 or less with respect to 100, and the organic medium comprises at least one organic solvent having a solubility in water of 1% or less. It becomes a dispersion liquid containing.
The polypyrrole fine particles nano-dispersed in the organic solvent layer obtained by the above production method (1) have at least one highly volatile organic solvent having a solubility in water of 1% or less (the volatile rate of butyl acetate is 100%). In which the volatilization rate is greater than 10), and the polypyrrole fine particles nanodispersed in the organic solvent layer obtained by the production method (2) have a solubility in water of 1% or less. At least one highly volatile organic solvent (the volatilization rate is greater than 10 when the volatilization rate of butyl acetate is 100), at least one low volatility solvent (butyl acetate) having a solubility of 1% or less The volatilization rate is 10 or less with a volatilization rate of 100), or nano-dispersed in a mixture of a highly volatile organic solvent and a low volatile organic solvent having a solubility of 1% or less Is polypyrrole particles.

The low-volatile organic solvent used for dilution (the volatilization rate when the volatilization rate of butyl acetate is set to 100 is 10 or less) is a low-volatility organic solvent that does not cause layer separation. 1% or less or 1% or more can be used, for example, a terpentine organic solvent, specifically mineral spirit isoparaffin terpine oil, limonene of orange oil, P-menthane, α-pinene, β-pinene, terpinolene, isobornyl acetate, terpinyl acetate, terpineol, α-terpineol, dihydroterpineol or cyclohexanol, methyl carbitol, butyl cellosolve, propylene carbonate and the like can be mentioned.
The low-volatile organic solvent can be used alone or as a mixture of two or more.

The solid content concentration of the polypyrrole fine particles in the diluted dispersion is 0.2 to 10.0%, preferably 0.5 to 6.0%, more preferably 1.0 to 4.0%. It is a range.
There are many highly volatile organic solvents before dilution, so the solid content concentration of the polypyrrole fine particles becomes too low when diluted with a low volatile solvent and the content of the low volatile organic solvent is 80% or more. In advance, the highly volatile organic solvent is distilled off to some extent and concentrated to adjust the solid content concentration of the polypyrrole fine particles so as not to become too low.

The dispersion liquid in which polypyrrole fine particles are dispersed in the organic medium of the present invention prepared as described above can be used for a conductive paint. The conductive coating material comprises polypyrrole fine particles dispersed in an organic medium, and a resin such as a dispersion stabilizer, a thickener, and a binder can be added as required for the purpose of application and application.
Examples of the binder include polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly (N-vinylcarbazole), hydrocarbon resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, acetic acid. Examples thereof include vinyl, ABS resin, polyurethane resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin, and silicon resin.
The amount of the binder used is 0.2 to 10 parts by mass with respect to 1 part by mass of the polypyrrole fine particles.

  Moreover, an electroconductive thin film can be obtained by apply | coating said electroconductive coating material to a base material, and making it dry. At this time, a thin film in which 60% or more of the polypyrrole fine particles are present in the upper half is formed. The object to be applied is not particularly limited, but it is necessary to select it so as not to be damaged by the organic solvent contained in the conductive paint. Also, the coating method is not particularly limited, and printing or coating can be performed using, for example, a gravure printing machine, an inkjet printing machine, dipping, a spin coater, a roll coater, or the like.

  In addition, the dispersion liquid in which the polypyrrole fine particles are dispersed in the organic medium of the present invention is not limited to the conductive paint. It can be preferably applied to various uses such as materials.

  The following examples illustrate the invention in more detail. However, the examples are for illustrating the present invention and are not intended to limit the present invention in any way.

Example 1
Dissolve 8 mmol of di-2-ethylhexyl sodium sulfosuccinate (anionic surfactant: Perex OT-P) in 900 mL of ion-exchanged water, add 100 mmol of pyrrole monomer, stir for 30 minutes, and then 50 mL (corresponding to 50 mmol) of 1M aqueous ammonium persulfate solution For 1 hour (polymerization rate 50%, average particle diameter 78 nm). Next, 50 mL of limonene was added and stirred for 4 hours. After completion of the stirring, the organic phase was recovered, washed several times with ion-exchanged water, and black polypyrrole fine particles (average particle size 85 nm) having a solid content of 10% were obtained in a state dispersed in limonene. Methyl carbitol was added to this dispersion, and the solid content concentration of the fine particles was diluted to 1%. This was designated as Solution 1.

Example 2
8 mmol of di-2-ethylhexyl sodium sulfosuccinate was dissolved in 100 mL of toluene, and further 800 mL of ion-exchanged water was added and stirred until emulsification was maintained at 20 ° C. To the obtained emulsion, 100 mmol of pyrrole monomer was added and stirred for 30 minutes, and then 100 mL of a 1M aqueous ammonium persulfate solution (corresponding to 100 mmol) was added in small portions and stirred for 4 hours. After the completion of stirring, the organic phase was recovered, washed several times with ion exchange water, and dispersed in toluene to obtain black polypyrrole fine particles (average particle size 85 nm) having a solid content of 5%. Methyl carbitol was added to this dispersion, and the solid content concentration of the fine particles was diluted to 1%. This was designated as Solution 2.

Example 3
0.5 parts by mass of Super Becamine J-820 (Dainippon Ink Chemical), a melamine binder, is added to Solution 1 with respect to 1 part by mass of polypyrrole solids, so that the solids concentration becomes 1% with methyl carbitol. Dilute to This was designated as Solution 3.

Example 4
Add 2 parts by mass of Super Becamine J-820 (Dainippon Ink Chemical), a melamine binder, to 1 part by mass of polypyrrole solids in Solution 1 and dilute with methyl carbitol to a solids concentration of 1%. did. This was designated as Solution 4.

Example 5
Add 0.5 parts by mass of Superbeccamin J-820 (Dainippon Ink Chemical Co., Ltd.), a melamine binder, to 1 part by mass of polypyrrole solids to solution 2, so that the solids concentration becomes 1% with methyl carbitol. Dilute to This was designated as Solution 5.

Example 6
Add 2 parts by mass of Super Becamine J-820 (Dainippon Ink Chemical Co., Ltd.), a melamine binder, to Solution 2 with respect to 1 part by mass of polypyrrole solids, and dilute with methyl carbitol to a solids concentration of 1%. did. This was designated as Solution 6.

Comparative Example 1
Dissolve 8 mmol of di-2-ethylhexyl sodium sulfosuccinate (anionic surfactant: Perex OT-P) in 900 mL of ion-exchanged water, add 100 mmol of pyrrole monomer, stir for 30 minutes, and then 50 mL (corresponding to 50 mmol) of 1M aqueous ammonium persulfate solution For 1 hour (polymerization rate 50%, average particle diameter 78 nm). Next, 50 mL of toluene was added and stirred for 4 hours. After completion of the stirring, the organic phase was recovered, washed several times with ion-exchanged water, and black polypyrrole fine particles (average particle size 85 nm) having a solid content of 10% were obtained in a state dispersed in toluene. Isopropanol was added to this dispersion, and the solid content concentration of the fine particles was diluted to 1%. This was designated as Solution 7.

Comparative Example 2
8 mmol of di-2-ethylhexyl sodium sulfosuccinate was dissolved in 100 mL of toluene, and further 800 mL of ion-exchanged water was added and stirred until emulsification was maintained at 20 ° C. To the obtained emulsion, 100 mmol of pyrrole monomer was added and stirred for 30 minutes, and then 100 mL of a 1M aqueous ammonium persulfate solution (corresponding to 100 mmol) was added in small portions and stirred for 4 hours. After the completion of stirring, the organic phase was recovered, washed several times with ion exchange water, and dispersed in toluene to obtain black polypyrrole fine particles (average particle size 85 nm) having a solid content of 5%. Isopropanol was added to this dispersion, and the solid content concentration of the fine particles was diluted to 1%. This was designated as Solution 8.

Comparative Example 3
Dissolve 8 mmol of di-2-ethylhexyl sodium sulfosuccinate (anionic surfactant: Perex OT-P) in 900 mL of ion-exchanged water, add 100 mmol of pyrrole monomer, stir for 30 minutes, and then 50 mL (corresponding to 50 mmol) of 1M aqueous ammonium persulfate solution For 1 hour (polymerization rate 50%, average particle diameter 78 nm). Next, 150 mL of toluene was added and stirred for 4 hours. After completion of the stirring, the organic phase was recovered, washed several times with ion exchange water, and dispersed in toluene to obtain black polypyrrole fine particles (average particle size 85 nm) having a solid content of 3.3%. Methyl carbitol was added to this dispersion, and the solid content concentration of the fine particles was diluted to 1%. This was designated as Solution 9.

Comparative Example 4
0.1 parts by mass of Super Becamine J-820 (Dainippon Ink Chemical), which is a melamine binder, is added to Solution 7 with respect to 1 part by mass of polypyrrole solids, and diluted with isopropanol so that the solids concentration becomes 1%. did. This was designated as Solution 10.

Comparative Example 5
To solution 7, 2 parts by mass of Super Becamine J-820 (Dainippon Ink Chemical Co., Ltd.), which is a melamine binder, was added to 1 part by mass of polypyrrole solids, and diluted with isopropanol so that the solids concentration was 1%. This was designated as Solution 11.

Comparative Example 6
0.1 parts by mass of Superbecamine J-820 (Dainippon Ink Chemical), a melamine binder, is added to Solution 8 with respect to 1 part by mass of polypyrrole solids, and diluted with isopropanol so that the solids concentration becomes 1%. did. This was designated as Solution 12.

Comparative Example 7
To Solution 8, 2 parts by mass of Super Becamine J-820 (Dainippon Ink Chemical Co., Ltd.), which is a melamine binder, was added to 1 part by mass of polypyrrole solid content, and diluted with isopropanol so that the solid content concentration became 1%. This was designated as Solution 13.

Comparative Example 8
Add 2 parts by mass of Super Becamine J-820 (Dainippon Ink Chemical Co., Ltd.), a melamine-based binder, to Solution 9 with respect to 1 part by mass of polypyrrole solids, and dilute with methyl carbitol to a solids concentration of 1%. did. This was designated as Solution 14.

Test example 1
The above solutions 1 to 14 were applied to a 100 μm PET film with a bar coater # 8 and dried at 140 ° C. for 10 minutes to obtain a coating film having a thickness of 100 nm. The initial resistance value, resistance value change with time, adhesion (only when a binder was used) and total light transmittance of this coating film were measured. The results are shown in Table 1.

The measurement was performed by the following method.
(Average particle size (nm))
The measurement was performed by a laser Doppler method using Nanotrac UPA150 manufactured by Microtrac.
(Polymerization rate (%))
The residual monomer was measured using a gas chromatograph and calculated from the ratio between the added amount and the residual monomer.
(Reducing fine particle abundance ratio (upper layer / lower layer))
The coating film was cut into a width of 60 nm using an ultramicrotome (Leica Co., Ltd .: Ultracut S), and a cross section was photographed with a transmission electron microscope (JEOL Ltd .: JEM-1200 EXM). The area ratio between the particle part and the binder part was determined from the obtained image. In addition, the value which calculated the average value after creating 10 samples and measuring it similarly was used.
(Initial resistance (Ω))
The resistance value of the conductive coating film was measured with an MCP-HT450 type high resistivity meter manufactured by Mitsubishi Chemical Corporation.
(Total light transmittance (%))
Measurement was performed using a haze meter in accordance with JIS K7105.

Further, resistance value change with time and adhesion (only when a binder was used) were evaluated according to the following criteria.
(Resistance value change with time)
Time taken for the resistance value to increase by one digit ◎: 3 months or more ○: 2 months or more △: 1 month or more and 2 months or less ×: 1 month or less (adhesion)
Based on the JIS H8504 tape test method, 100 2 mm square strips were prepared with a cutter, and then a peeling test was performed by a tape test.
○: No peeling ×: 90% or more peeling Note that each description in the table means the following.
Polymerization method: (1) and (2) mean a polymerization method according to production method (1) and production method (2), respectively.
Polymerization rate: Polymerization rate (%) of polypyrrole before adding the organic solvent in the case of employing the polymerization method (2) (Examples 1, 3, 4, Comparative Examples 1, 3, 4, 5, 8).
Average particle diameter before addition: average particle diameter of polypyrrole before adding the organic solvent when the polymerization method (2) is employed (Examples 1, 3, 4, Comparative Examples 1, 3, 4, 5, 8) ( nm).
Average particle size after reaction: The average particle size of polypyrrole after recovery of the organic phase (nm).
Organic solvent: When the polymerization method (1) is adopted, the type of the organic solvent added before the polymerization is shown, and when the polymerization method (2) is adopted, the type of the solvent added during the polymerization is shown.
Diluent: The type of low volatility organic solvent used for dilution.
Low volatile solvent content: content (%) of low volatile organic solvent in the final dispersion.
Binder amount: The amount (part by mass) of the binder used relative to 1 part by mass of the polypyrrole solid content.
Table 1

As shown in Examples 1 and 2, a dispersion prepared using any of polypyrrole produced by employing polymerization method (2) (Example 1) or polymerization method (1) (Example 2), If the content of the low volatile organic solvent is 80% or more, it shows that a low initial resistance value is exhibited, the resistance value is little changed with time, and a coating film showing a high total light transmittance is obtained. However, at this time, the polypyrrole fine particle abundance ratio in the upper layer / lower layer of the coating film was 65/35, and many polypyrrole fine particles were present in the upper layer.
In Example 3 (in which the amount of binder added is 0.5 parts by mass) and Example 4 (in which the amount of binder added is 2 parts by mass), in which Example 1 (in which polymerization method (2) is employed) is added, a binder is used. In addition to the excellent effects shown, it showed high adhesion, and the total light transmittance was improved as compared with Example 1. At this time, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was As in Example 1, it was 65/35.
In Example 2 (in which the polymerization method (1) is employed), a binder is added in Example 5 (binder addition amount 0.5 parts by mass) and Example 6 (binder addition amount 2 parts by mass). In addition to the excellent effects shown, it showed high adhesion, and the total light transmittance was improved as compared with Example 2. At this time, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was As in Example 1, it was 65/35.
In Comparative Example 1 in which a highly volatile organic solvent (isopropanol) was used instead of the low volatile organic solvent (methyl carbitol) used as the dilution solvent in Example 1, the initial resistance value was low, but the resistance value was low. The change with time became larger. In this case, the polypyrrole fine particle abundance ratio in the upper layer / lower layer of the coating film was 50/50, and the polypyrrole fine particles were uniformly present in the upper layer and the lower layer, unlike Example 1.
In Comparative Example 2 in which a highly volatile organic solvent (isopropanol) was used instead of the low volatile organic solvent (methyl carbitol) used as the diluting solvent in Example 2, the initial resistance value was low, but the resistance value was low. The change with time became larger. In this case, the polypyrrole fine particle abundance ratio in the upper layer / lower layer of the coating film was 50/50, and the polypyrrole fine particles were uniformly present in the upper layer and the lower layer, unlike Example 2.
In Comparative Example 3 in which the amount of the low-volatile organic solvent (methyl carbitol) used as the dilution solvent in Example 1 was reduced to 70% in which the content of the low-volatile organic solvent was less than 80%, Although the resistance value was low, the change with time of the resistance value was somewhat larger. In this case, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was 55/45, but there was a tendency that a large amount of polypyrrole fine particles existed in the upper layer, but it was insufficient.
In Comparative Example 4 in which a binder is added to Comparative Example 1 (binder addition amount: 0.1 parts by mass), the binder amount of about 0.1 parts by mass does not show improvement in adhesion and improvement in total light transmittance. It has been shown. In this case, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was 50/50 as in Comparative Example 1.
In Comparative Example 5 in which a binder is added to Comparative Example 1 (2 parts by mass of binder added), high adhesiveness is exhibited, and the total light transmittance is improved as compared with Comparative Example 1, and the resistance value changes with time. However, the change with time of the resistance value was still inferior to that of Example 1. In this case, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was 50/50 as in Comparative Example 1.
In Comparative Example 6 in which a binder is added to Comparative Example 2 (binder addition amount: 0.1 parts by mass), the binder amount of about 0.1 parts by mass does not show improvement in adhesion and improvement in total light transmittance. It has been shown. In this case, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was 50/50 as in Comparative Example 2.
In Comparative Example 7 in which a binder is added to Comparative Example 2 (2 parts by mass of binder added), high adhesion is exhibited, and the total light transmittance is improved as compared with Comparative Example 2, and the resistance value changes with time. However, the change over time in the resistance value was still inferior to that in Example 2. In this case, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was 50/50 as in Comparative Example 2.
In Comparative Example 8 in which a binder is added to Comparative Example 3 (binder addition amount 2 parts by mass), high adhesiveness is exhibited, and the total light transmittance is improved as compared with Comparative Example 3, and the resistance value changes with time. However, the change over time in the resistance value was still inferior to that in Example 2. In this case, the abundance ratio of the polypyrrole fine particles in the upper layer / lower layer of the coating film was 55/45 as in Comparative Example 3.

It is the figure which modeled the transmission electron micrograph of the cross-sectional view of the coating film formed using the dispersion liquid of the polypyrrole fine particle which has a highly volatile organic solvent as a main component. It is the figure which modeled the transmission electron micrograph of the cross-sectional view of the coating film formed using the dispersion liquid of the polypyrrole fine particle which has a low-volatile organic solvent as a main component. It is a graph which shows the relationship between the polymerization rate (%) of the polypyrrole in an aqueous medium, and the average particle diameter (nm) of the polypyrrole obtained at that time.

Explanation of symbols

1: Base film 2: Coating layer 3: Polypyrrole fine particles

Claims (4)

A dispersion in which polypyrrole fine particles are dispersed in an organic medium,
The organic medium is composed of one kind or two or more kinds of organic solvents that do not cause layer separation, and mineral spirits isoparaffin, turpentine oil, limonene, P-menthane, α-pinene, β-pinene, terpinolene, isobornyl. 80% or more of at least one low-volatile organic solvent selected from the group consisting of acetate, terpinyl acetate, terpineol, α-terpineol, dihydroterpineol, cyclohexanol, methyl carbitol, butyl cellosolve and propylene carbonate A dispersion characterized by that. The organic medium has a solubility in water of 1% or less and is selected from the group consisting of butyl acetate, toluene, methyl ethyl ketone, cyclohexane, n-octane, n-octanol, isopropanol, methyl benzoate and diethyl ether. dispersion according to claim 1, characterized in that it comprises at least one highly volatile organic solvent. The organic medium does not contain a highly volatile organic solvent selected from the group consisting of butyl acetate, toluene, methyl ethyl ketone, cyclohexane, n-octane, n-octanol, isopropanol, methyl benzoate and diethyl ether. The dispersion according to claim 1 . The dispersion liquid according to any one of claims 1 to 3 , wherein an average particle size of the pyrrole fine particles is in a range of 10 to 100 nm.

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