JP7703873B2 - Method for producing organic solvent-type polythiophene-based conductive polymer liquid composition, and liquid composition obtained by said method - Google Patents

Description

The present invention relates to a method for producing an organic solvent-type polythiophene-based conductive polymer liquid composition, and a liquid composition obtained by the method.

Polythiophenes have been studied in a wide range of fields, including solid electrolytic capacitors, antistatic agents, hole injection agents for solar cells, and transparent electrodes, due to their high electrical conductivity. Polythiophene-based conductive materials are generally classified into aqueous dispersions in which a water-soluble acidic polymer such as polystyrene sulfonic acid or polyvinyl sulfonic acid is used as an external dopant, and aqueous solutions containing self-doped conductive polymers that do not require an external dopant. A representative example of the former is PEDOT:PSS, a conductive polymer obtained by polymerizing 3,4-ethylenedioxythiophene (EDOT) in the presence of polystyrene sulfonic acid (PSS), and an example of the latter is polythiophenes substituted with linear or branched alkylene sulfonic acids such as 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonic acid polymers (Patent Document 1), both of which have electrical conductivity of several hundred S/cm or more.

On the other hand, there are few reports on highly conductive polythiophenes that disperse or dissolve in highly polar solvents. For example, Luebben et al. have reported a block copolymer of PEDOT and polyethylene glycol with toluenesulfonato groups or perchlorate as an external dopant (Non-Patent Document 1). This block copolymer can be dispersed in polar organic solvents such as propylene carbonate and nitromethane, and its conductivity is 10 ⁻⁴ S/cm to 1 S/cm. Non-Patent Document 2 reports a quaternary ammonium salt compound of poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid) (PEDOT-S), which is a self-doped conductive polymer. This compound can be dispersed in a mixture of methanol and chloroform, and its conductivity is 0.4 S/cm to 0.8 S/cm.

An organic solvent-based polythiophene-based conductive polymer liquid composition has also been reported in Patent Document 2, but the manufacturing method for this composition is difficult to implement industrially because it requires long-term ultrasonic irradiation.

International Publication WO2014/007299 Brochure JP 2019-210356 A

Polymeric Materials: Science & Engineering, 2004, Vol. 91, p. 979 Scientific Reports, 2015, Vol. 5, 11242

The present invention has been made in consideration of the above-mentioned background art, and its object is to provide a method for producing an organic solvent-type polythiophene-based conductive polymer liquid composition that is industrially feasible.

As a result of intensive research, the inventors discovered that the manufacturing method described below can solve the above problems, and thus completed the present invention.

That is, the present invention resides in the following [1] to [11].
[1] At least one of the following general formulas (1) and (2):

{In the above general formulas (1) and (2), R ¹ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. ^{M 1} represents an ammonium ion represented by [NH(R ² )(R ³ ) ₂ ] ⁺ , or a quaternary ammonium cation represented by [N(R ² )(R ³ ) ₃ ] ⁺ . R ² represents an alkyl group having 7 to 20 carbon atoms, or an alkyl group having a substituent and a total of 7 to 20 carbon atoms. Each R ³ independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having a substituent and a total of 1 to 20 carbon atoms. m represents an integer of 1 to 6.}
A method for producing a conductive polymer liquid composition, comprising mixing a solid of polythiophene containing a structural unit represented by the following formula:
[2] The method for producing the conductive polymer liquid composition according to [1], characterized in that water is mixed so that the content of water in the obtained conductive polymer liquid composition is 3 to 40 wt %.
[3] The method according to [1], wherein m is 2 or 3.
[4] The method according to [1], wherein R ¹ is a methyl group.
[5] The method according to [1], wherein the highly polar organic solvent is one or a mixed solvent of two or more selected from the group consisting of alcohol solvents, ketone solvents, ether solvents, ester solvents, glycol solvents, glycol ester solvents, glycol ether solvents, glyme solvents, amide solvents, and sulfur-containing solvents.
[6] At least one of the following general formulas (1) and (2):

{In the above general formulas (1) and (2), R ¹ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. ^{M 1} represents an ammonium ion represented by [NH(R ² )(R ³ ) ₂ ] ⁺ , or a quaternary ammonium cation represented by [N(R ² )(R ³ ) ₃ ] ⁺ . R ² represents an alkyl group having 7 to 20 carbon atoms, or an alkyl group having a substituent and a total of 7 to 20 carbon atoms. Each R ³ independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having a substituent and a total of 1 to 20 carbon atoms. m represents an integer of 1 to 6.}
A conductive polymer liquid composition comprising a polythiophene having a structural unit represented by the following formula:
[7] The conductive polymer liquid composition according to [6], wherein m is 2 or 3.
[8] The conductive polymer liquid composition according to [6], wherein R ¹ is a methyl group.
[9] The conductive polymer liquid composition according to [6], wherein the highly polar organic solvent is one solvent or a mixed solvent of two or more solvents selected from the group consisting of alcohol solvents, ketone solvents, ether solvents, ester solvents, glycol solvents, glycol ester solvents, glycol ether solvents, glyme solvents, amide solvents, and sulfur-containing solvents.
[10] The conductive polymer liquid composition according to [6], characterized in that the water content is 5 to 30% by weight.
[11] The conductive polymer liquid composition according to [6], wherein the liquid composition is a liquid composition comprising the polythiophene, the highly polar organic solvent, and the water.

The manufacturing method of the present invention makes it possible to industrially produce organic solvent-type polythiophene-based conductive polymer liquid compositions, which have previously been difficult to produce industrially.

The organic solvent-type polythiophene-based conductive polymer liquid composition of the present invention, which is characterized by containing a small amount of water, can be prepared at a higher concentration than a liquid composition that does not contain any water. Therefore, it has the effect of providing excellent film-forming properties without impairing conductivity or operability.

The present invention is described in detail below.

As described above, the present invention relates to a method for producing a conductive polymer liquid composition, which is characterized by mixing a solid polythiophene containing at least structural units represented by the general formulas (1) and (2) above, a highly polar organic solvent, and water, and to a conductive polymer liquid composition obtained by the method.

The polythiophene of the present invention is a polythiophene containing structural units represented by the structural units represented by the above general formulas (1) and (2).

The structural unit represented by the above general formula (2) represents the doped state of the structural unit represented by the above general formula (1), and the doped state is expressed by the sulfo group or sulfonate group in the structural unit represented by the above general formula (1) acting as a p-type dopant.

In the above general formula (1) or (2), R ¹ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom.

The above-mentioned alkyl group having 1 to 6 carbon atoms is not particularly limited, but examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a cyclopentyl group, an n-hexyl group, a 2-ethylbutyl group, and a cyclohexyl group.

The above halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.

Of these, the substituent ^R1 is preferably a hydrogen atom, a methyl group, an ethyl group, a fluorine atom, a chlorine atom, or a bromine atom, more preferably a hydrogen atom, a methyl group, or a fluorine atom, and more preferably a methyl group, from the viewpoint of film-forming properties.

M ¹ represents an ammonium ion represented by [NH(R ² )(R ³ ) ₂ ] ⁺ or a quaternary ammonium cation represented by [N(R ² )(R ³ ) ₃ ] ⁺ .

The ammonium ion refers to an amine compound represented by [N(R ² )(R ³ ) ₂ ] to which a hydron (H ⁺ ) is added to become a cationic species (conjugate acid), and the amine compound reacts with a sulfonic acid group to form a conjugate acid, thereby becoming the ammonium ion.

The quaternary ammonium cation ([N( ^R2 )( ^R3 ) ₃ ] ⁺ ) refers to a cationic species (conjugate acid) formed by eliminating the anion represented by ^M3 from a quaternary ammonium cation compound represented by [N( ^R2 )( ^R3 ) ₃ ] ^{+ M3} . The quaternary ammonium cation compound reacts with a sulfonic acid group to eliminate the anion represented by ^M3 , forming a quaternary ammonium cation.

The substituent ^R2 represents an alkyl group having 7 to 20 carbon atoms, or an alkyl group having a substituent and a total of 7 to 20 carbon atoms.

The alkyl group having 7 to 20 carbon atoms is not particularly limited, but examples thereof include n-heptyl, methylhexyl, n-octyl, methylhexyl, ethylhexyl, n-nonyl, n-decyl, ethyloctyl, butylhexyl, n-undecyl, n-dodecyl, n-hexadecyl, n-heptadecyl, octylnonyl, n-octadecyl, n-nonadecyl, n-icosyl, and octyldodecane groups.

Examples of the alkyl group having a total of 7 to 20 carbon atoms and having the above-mentioned substituent include an alkyl group having a total of 7 to 20 carbon atoms and having a halogen atom, an amino group, or a hydroxy group, and specific examples include an 8-hydroxyoctyl group or a 9-aminononyl group.

Of these, from the viewpoint of availability, the substituent ^R2 is preferably an n-heptyl group, a methylhexyl group, an n-octyl group, a 2-ethylhexyl group, a methylheptyl group, an n-nonyl group, an n-decyl group, or an n-dodecyl group.

The substituents ^R3 each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having a substituent and a total of 1 to 20 carbon atoms.

The alkyl group having 1 to 20 carbon atoms is not particularly limited, but examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, n-hexyl, 2-ethylbutyl, cyclohexyl, n-heptyl, methylhexyl, n-octyl, methylheptyl, ethylhexyl, n-nonyl, n-decyl, ethyloctyl, butylhexyl, n-undecyl, n-dodecyl, n-hexadecyl, n-heptadecyl, octylnonyl, n-octadecyl, n-nonadecyl, n-icosyl, and octyldodecane.

Examples of the alkyl group having a total of 1 to 20 carbon atoms and having the above-mentioned substituent include an alkyl group having a total of 7 to 20 carbon atoms and having a halogen atom, an amino group, or a hydroxy group, and specific examples include a trifluoromethyl group, a 2-hydroxyethyl group, an 8-hydroxyoctyl group, and a 9-aminononyl group.

Of these, the substituents ^R3 are preferably each independently a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, a 2-ethylbutyl group, an n-heptyl group, a methylhexyl group, an n-octyl group, a 2-ethylhexyl group, a methylheptyl group, an n-nonyl group, an n-decyl group, or an n-dodecyl group.

The amine compound represented by [N(R ² )(R ³ ) ₂ ] is not particularly limited, and examples thereof include n-heptylamine, di-n-heptylamine, tri-n-heptylamine, n-octylamine, di-n-octylamine, n-(2-ethylhexyl)amine, di-n-(2-ethylhexyl)amine, tri-n-(2-ethylhexyl)amine, tri-n-octylamine, N-methyl-di-n-octylamine, n-nonylamine, di-n-nonylamine, tri-n-nonylamine, n-decylamine, di-n-decylamine, tri-n-decylamine, n-dodecylamine, di-n-dodecylamine, tri-n-dodecylamine, n-hexadecylamine, di-n-hexadecylamine, tri-n-hexadecylamine, N,N-dimethyl-n-heptylamine, N,N-dimethyl-n-octylamine, N,N-dimethyl-n-nonylamine, N,N-dimethyl-n-decylamine, N,N-dimethyl-n-dodecylamine, N,N-dimethyl-n-hexadecylamine, N,N-dimethyl-n-octadecylamine, N,N-dimethyl-n-icosylamine, N,N-diethyl-n-heptylamine, N,N-diethyl-n-octylamine, N,N-diethyl-n-nonylamine, N,N-diethyl-n-decylamine, N,N-dimethyl-n-diicosylamine, N,N-diethyl-n-heptylamine, N,N-diethyl-n-octylamine, N,N-diethyl-n-nonylamine, N,N-diethyl-n-decylamine, N,N-diethyl n-dodecylamine, N,N-diethyl-n-hexadecylamine, N,N-diethyl-n-octadecylamine, N,N-diethyl-n-icosylamine, N-methylhexylamine, 2-octylamine, N,N-dimethyl-2-ethylhexane-1-amine, N,N-diisopropyl-2-ethylhexane-1-amine, 6-methyl-1-heptylamine, di(6-methyl-1-heptyl)amine, tris(6-methyl-1-heptyl)amine, 2-ethylhexylamine, di(2-ethylhexyl)amine, tris(2-ethylhexyl)amine, methyloctylamine, methylnonylamine, methyldodecylamine, methylhexadecylamine, methyloctadecylamine, ethyl Examples of the amine include heptylamine, ethyloctylamine, ethylnonylamine, ethyldodecylamine, ethylhexadecylamine, ethyloctadecylamine, 7-hydroxyheptylamine, 8-hydroxyoctylamine, 9-hydroxynonylamine, 10-hydroxydecylamine, 12-hydroxydodecylamine, 16-hydroxyhexadecylamine, 18-hydroxyoctadecylamine, 20-hydroxyicosylamine, 7-aminoheptylamine, 8-aminooctylamine, 9-aminononylamine, 10-aminodecylamine, 12-aminododecylamine, 16-aminohexadecylamine, 18-aminooctadecylamine, and 20-aminoicosylamine.

The ammonium ion represented by the above [NH(R ² )(R ³ ) ₂ ] ⁺ is not particularly limited, and examples thereof include n-heptylammonium, di-n-heptylammonium, tri-n-heptylammonium, n-octylammonium, di-n-octylammonium, n-(2-ethylhexyl)ammonium, di-n-(2-ethylhexyl)ammonium, tri-n-(2-ethylhexyl)ammonium, tri-n-octylammonium, N-methyl-di-n-octylammonium, n-nonylammonium, di-n-nonylammonium, tri-n-nonylammonium, n-decylammonium, di-n-decylammonium, tri-n-decylammonium, n-dodecylammonium, di-n-dodecylammonium, tri-n-dodecylammonium, n-hexadecylammonium, di-n-hexadecylammonium, tri-n-hexadecylammonium, decyl ammonium, n-octadecyl ammonium, di-n-octadecyl ammonium, tri-n-octadecyl ammonium, n-icosyl ammonium, di-n-icosyl ammonium, tri-n-icosyl ammonium, N,N-dimethyl-n-heptyl ammonium, N,N-dimethyl-n-octyl ammonium, N,N-dimethyl-n-nonyl ammonium, N,N-dimethyl-n-decyl ammonium, N,N-dimethyl-n-dodecyl ammonium, N,N-dimethyl-n-hexadecyl ammonium, N,N-dimethyl-n-octadecyl ammonium, N,N-dimethyl-n-icosyl ammonium, N,N-diethyl-n-heptyl ammonium, N,N-diethyl-n-octyl ammonium, N,N-diethyl-n-nonyl ammonium, N,N-diethyl-n-decyl ammonium, N,N-diethyl n-dodecylammonium, N,N-diethyl-n-hexadecylammonium, N,N-diethyl-n-octadecylammonium, N,N-diethyl-n-icosylammonium, N-methylhexylammonium, 2-octylammonium, N,N-dimethyl-2-ethylhexane-1-ammonium, N,N-diisopropyl-2-ethylhexane-1-ammonium, 6-methyl-1-heptylammonium, di(6-methyl-1-heptyl)ammonium, tris(6-methyl-1-heptyl)ammonium, 2-ethylhexylammonium, di(2-ethylhexyl)ammonium, tris(2-ethylhexyl)ammonium, methyloctylammonium, methylnonylammonium, methyldodecylammonium, methylhexadecylammonium, methyloctadecylammonium, ethylheptyl Examples of the ammonium salt include ammonium, ethyloctylammonium, ethylnonylammonium, ethyldodecylammonium, ethylhexadecylammonium, ethyloctadecylammonium, 7-hydroxyheptylammonium, 8-hydroxyoctylammonium, 9-hydroxynonylammonium, 10-hydroxydecylammonium, 12-hydroxydodecylammonium, 16-hydroxyhexadecylammonium, 18-hydroxyoctadecylammonium, 20-hydroxyicosylammonium, 7-aminoheptylammonium, 8-aminooctylammonium, 9-aminononylammonium, 10-aminodecylammonium, 12-aminododecylammonium, 16-aminohexadecylammonium, 18-aminooctadecylammonium, and 20-aminoicosylammonium.

The quaternary ammonium cation represented by [N(R ² )(R ³ ) ₃ ] ⁺ is not particularly limited, but examples thereof include tetraheptylammonium cation, tetraoctylammonium cation, tetranonylammonium cation, tetradecylammonium cation, tetradodecylammonium cation, tetrahexadecylammonium cation, tetraoctadecylammonium cation, tetraicosylammonium cation, and tetraethylhexylammonium cation.

The quaternary ammonium cation represented by [N(R ² )(R ³ ) ₃ ] ⁺ is produced by reacting a quaternary ammonium cation compound represented by [N(R ² )(R ³ ) ₃ ] ⁺ M ³ with a polythiophene containing structural units represented by the structural units represented by the general formulas (1) and (2) above.

The anion represented by ^M3 above is not particularly limited, but examples thereof include a chloride ion, a bromide ion, an iodide ion, a hydroxide ion, an acetate ion, a trifluoroacetate ion, a benzoate ion, a methanesulfonate ion, a trifluoromethanesulfonate ion, a benzenesulfonate ion, and a paratoluenesulfonate ion.

The quaternary ammonium cation compound represented by the above-mentioned [N(R ² )(R ³ ) ₃ ] ⁺ M ³ is not particularly limited, and examples thereof include tetramethylammonium chloride, tetraethylammonium chloride, tetra-normal-propylammonium chloride, tetra-normal-butylammonium chloride, tetra-normal-hexylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetra-normal-propylammonium bromide, tetra-normal-butylammonium bromide, tetra-normal-hexylammonium bromide, tetramethylammonium iodide, tetraethylammonium iodide, tetra-normal-propylammonium iodide, tetra-normal-butylammonium iodide, tetra-normal-hexylammonium iodide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra-normal-propylammonium hydroxide, tetra-normal-butylammonium hydroxide, and tetra-normal-hexylammonium hydroxide.

In the above general formula (1) or (2), m represents an integer of 1 to 6, preferably an integer of 1 to 4, and more preferably an integer of 2 to 3.

The polymer serving as the raw material for the polythiophene of the present invention can be produced by reacting a polythiophene containing at least structural units represented by the following general formulas (3) and (4) with an amine compound represented by [N(R ² )(R ³ ) ₂ ] or ^a quaternary ammonium cation compound represented by [N(R ² )(R 3 ) ₃ ] ⁺ M ^3. After the reaction, it is preferable to combine, as necessary, operations such as solvent washing, reprecipitation, centrifugal sedimentation, ultrafiltration, dialysis, and ion exchange resin treatment.

[In the above general formulas (3) and (4), ^R1 represents an alkyl group having 1 to 6 carbon atoms or a halogen atom. m represents an integer of 1 to 6. ^M2 represents a hydrogen ion or an alkali metal ion.]
In the above general formula (3), ^M2 represents a hydrogen ion or an alkali metal ion.

The alkali metal ion is preferably, for example, a Li ion, a Na ion, or a K ion.

The polythiophene represented by the above general formula (3) or (4) is not particularly limited, but specifically includes 4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-butanesulfonic acid polymer, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonic acid polymer, polymer, sodium 4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-butanesulfonate polymer, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonate polymer, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonate polymer, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-ethyl-1-propanesulfonic acid sodium polymer, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-propyl-1-propanesulfonic acid sodium polymer, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-butyl-1-propanesulfonic acid sodium Polymer, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-pentyl-1-propanesulfonate polymer, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-hexyl-1-propanesulfonate polymer, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-hexyl-1-propanesulfonate polymer, oxin-2-yl)methoxy]-1-isopropyl-1-propanesulfonic acid sodium polymer, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isobutyl-1-propanesulfonic acid sodium polymer, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isopentyl-1-propanesulfonic acid sodium polymer Sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-fluoro-1-propanesulfonate polymer, potassium 4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-butanesulfonate polymer, potassium 3-[(2,3-dihydrothieno[3,4-b ]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonic acid potassium polymer, 4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-butanesulfonic acid ammonium polymer, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonic acid ammonium polymer, 4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-butanesulfonic acid triethylammonium polymer, or 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonic acid triethylammonium polymer.

To reiterate, the present invention relates to a method for producing a conductive polymer liquid composition, which is characterized by mixing a solid polythiophene containing at least structural units represented by the general formulas (1) and (2) described above, a highly polar organic solvent, and water.

The polythiophene is characterized as being solid as described above, but the solid state is not particularly limited and may be, for example, crystalline, granular, blocky, powdery, gel-like, paste-like, glassy, or any other solid state.

The highly polar organic solvent refers to a solvent that is highly compatible with water, and does not include organic solvents that have little solubility in water at room temperature (solubility less than 1% by weight). There are no particular limitations on such highly polar organic solvents, but for example, highly polar organic solvents that have a solubility in water at room temperature of 1% by weight or more and a Rohrschneider polarity parameter of 3.9 or more are preferred.

The highly polar organic solvent is not particularly limited, but examples thereof include alcohol solvents (e.g., methanol, ethanol, normal propyl alcohol, isopropyl alcohol, normal butanol, isobutanol, tertiary butanol, etc.), ketone solvents (acetone, methyl ethyl ketone, methyl propyl ketone, diacetone alcohol, cyclohexanone, etc.), ether solvents (methyl cellosolve, ethyl cellosolve, butyl cellosolve, 1,4-dioxane, etc.), ester solvents (methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, etc.), glycol solvents (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, etc.), glycol ester solvents (ethylene glycol monoethyl ether, acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, etc.), glycol ether solvents (methyl carbitol, ethyl carbitol, butyl carbitol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, etc.), glyme solvents (monoglyme, diglyme, triglyme, ethylglyme, ethyl diglyme, butyl diglyme, tetraglyme, etc.), amide solvents (N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylimidazolidinone, hexamethylphosphoric acid triamide, etc.), or sulfur-containing solvents (dimethyl sulfoxide, sulfolane, etc.).

These highly polar organic solvents may be used alone or in combination of two or more types of highly polar organic solvents.

As described above, the method for producing a conductive polymer liquid composition of the present invention is characterized by mixing a solid polythiophene containing at least structural units represented by the general formulas (1) and (2), a highly polar organic solvent, and water. In this production method, the amount of the solid polythiophene added is preferably 0.1 to 25% by weight of the entire composition produced, more preferably 0.1 to 15% by weight of the entire composition, and even more preferably 0.1 to 10% by weight of the entire composition.

In addition, in the production method of the present invention, the amount of the highly polar organic solvent added is preferably 60 to 97% by weight of the entire composition produced, more preferably 70 to 96% by weight of the entire composition, and even more preferably 80 to 95% by weight of the entire composition.

In addition, in the manufacturing method of the present invention, the amount of water added is preferably 3 to 40% by weight of the entire composition to be manufactured, more preferably 4 to 30% by weight of the entire composition, and even more preferably 5 to 20% by weight of the entire composition.

As described above, the method for producing a conductive polymer liquid composition of the present invention is characterized by mixing a solid polythiophene containing at least structural units represented by the general formulas (1) and (2) with a highly polar organic solvent and water. The method of mixing is not particularly limited, but examples include stirring and mixing with a stirrer tip, general stirring and mixing with a stirring blade, and stirring and mixing by homogenization treatment (for example, using a mechanical homogenizer, high-pressure homogenizer, etc.).

The mixing can be performed at an appropriate temperature, and is not particularly limited. For example, the mixing can be performed at a temperature in the range of 10 to 80°C, preferably 15 to 60°C, and more preferably 20 to 50°C.

The mixing is preferably carried out after oxygen degassing. The method for oxygen degassing is not particularly limited, but examples include reduced pressure treatment and nitrogen bubbling.

The stirring time is not particularly limited, but is preferably in the range of 1 minute to 12 hours, and more preferably in the range of 1 minute to 6 hours.

By carrying out such a mixing operation, a conductive polymer liquid composition of the present invention is obtained, which contains a polythiophene containing at least structural units represented by the above general formulas (1) and (2), a highly polar organic solvent, and water, and is characterized in that the content of the polythiophene is 0.1 to 25% by weight, the content of the highly polar organic solvent is 50 to 97% by weight, and the content of the water is 3 to 40% by weight.

The definition and preferred range of the polythiophene or highly polar organic solvent in the conductive polymer liquid composition of the present invention are as described above.

The conductive polymer liquid composition of the present invention is characterized in that the content of polythiophene is 0.1 to 25% by weight of the entire composition, but in terms of excellent film-forming properties, it is preferably 0.1 to 15% by weight of the entire composition, and more preferably 0.1 to 10% by weight of the entire composition.

In the conductive polymer liquid composition of the present invention, the content of the highly polar organic solvent is 50 to 97% by weight of the entire composition, but in terms of excellent film-forming properties, it is preferably 60 to 96% by weight of the entire composition, and more preferably 50 to 95% by weight of the entire composition.

The conductive polymer liquid composition of the present invention is characterized in that the water content is 3 to 40% by weight of the entire composition, but in terms of excellent film-forming properties, it is preferably 4 to 30% by weight of the entire composition, and more preferably 5 to 20% by weight of the entire composition.

The polythiophene in the liquid composition of the present invention is formed of fine particles having a particle diameter (D50) of about several nm to several hundred nm when measured by dynamic light scattering. Such fine particles are transparent in the visible light range, and appear to be dissolved in the solvent. In reality, the fine particles are dissolved or dispersed in the solvent, and in this application, this state is referred to as a "dissolved or dispersed" state.

The polythiophene of the present invention or a liquid composition containing the polythiophene is expected to be used in applications such as capacitors, touch sensors, antistatic agents, organic thin-film solar cells, organic electroluminescence (EL), and electrodes. The liquid composition containing the polythiophene of the present invention may contain additives such as known surfactants, lubricants, and/or binders depending on the application.

The surfactant is not particularly limited, but examples thereof include polymeric nonionic surfactants, amphoteric surfactants, fluorine-based surfactants, silicone-based surfactants, and acetylene glycol-based surfactants. More specifically, examples of polymeric nonionic surfactants include polyvinylpyrrolidone and copolymers of polyvinylpyrrolidone, but are not particularly limited. The average molecular weight of polyvinylpyrrolidone is preferably 1,000 to 2,000,000, and more preferably 10,000 to 1,500,000. The copolymer of polyvinylpyrrolidone is not particularly limited, but is preferably one having both hydrophilic and hydrophobic parts in the polymer chain, and examples thereof include copolymers in which polyvinylpyrrolidone is grafted to polyvinyl alcohol, [vinylpyrrolidone-vinyl acetate] block copolymers, [vinylpyrrolidone-methyl methacrylate] copolymers, [vinylpyrrolidone-normal butyl methacrylate] copolymers, and [vinylpyrrolidone-acrylamide] copolymers.

The amphoteric surfactant is not particularly limited, but examples thereof include betaine-type amphoteric surfactants. The betaine-type amphoteric surfactant is not particularly limited, but examples thereof include alkyl dimethyl betaine, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, etc.

The fluorosurfactant is preferably one having a perfluoroalkyl group, and examples thereof include, but are not limited to, perfluoroalkanes, perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, and perfluoroalkyl ethylene oxide adducts.

The silicone surfactant is not particularly limited, but examples thereof include polyether-modified polydimethylsiloxane, polyetherester-modified polydimethylsiloxane, hydroxyl group-containing polyether-modified polydimethylsiloxane, acrylic group-containing polyether-modified polydimethylsiloxane, acrylic group-containing polyester-modified polydimethylsiloxane, perfluoropolyether-modified polydimethylsiloxane, perfluoropolyester-modified polydimethylsiloxane, and silicone-modified acrylic compounds.

Fluorosurfactants and silicone surfactants are effective as leveling agents to improve the flatness of coating films.

The lubricants mentioned above refer to lubricants (lubricants for plastics, lubricants for resins) that are generally used as resin additives, and examples of such lubricants include those that have the effect of reducing friction between the plastic and the molding machine and between the plastic particles during plastic molding. The lubricants in question include those that act as external lubricants and those that are effective for internal lubrication, and in the present invention, either one may be used alone, or both may be used. Examples of lubricants that may be used include, but are not limited to, hydrocarbon-based lubricants (paraffin wax, synthetic polyethylene, liquid paraffin), fatty acid-based lubricants (stearic acid, behenic acid, 12-hydroxystearic acid), higher alcohol-based lubricants (stearyl alcohol), fatty acid amide-based lubricants (stearic acid amide, oleic acid amide, erucic acid amide, methylene bisstearic acid amide, ethylene bisstearic acid amide), ester-based lubricants (glycerin monostearate, glycerin monooleate, butyl stearate), etc.

The binder resin is not particularly limited, but examples thereof include acrylic resin, polyurethane resin, polymethyl methacrylate resin, styrene butadiene resin, vinyl acetate resin, polyamide resin, phenol resin, epoxy resin, melamine resin, thermosetting polyimide, nitrocellulose or other cellulose resin, polyvinyl alcohol resin, polystyrene sulfonic acid resin, polyvinylpyrrolidone resin, and polyester resin.

The conductive polymer liquid composition of the present invention can be applied to a support to form a coating film, which can then be dried to produce a conductive polymer film. This production method can produce a support coated with a conductive polymer film (hereinafter, the support and the conductive polymer film are collectively referred to as a "coated article").
The support is not particularly limited as long as the liquid composition of the present invention can be applied thereto, and examples thereof include polymeric substrates and inorganic substrates. The polymeric substrate is not particularly limited, and examples thereof include resins, nonwoven fabrics, and paper. The resins include polyethylene, polypropylene, polyethylene terephthalate, polyacrylate, and polycarbonate. The nonwoven fabric may be, for example, either natural fibers or synthetic fibers. The paper may be one mainly composed of general cellulose. The inorganic substrate is not particularly limited, and examples thereof include glass, glass fiber, ceramics, aluminum oxide, and tantalum oxide.

The method for applying the conductive polymer liquid composition is not particularly limited, but examples include casting, dipping, bar coating, dispenser, roll coating, gravure coating, flexographic printing, spray coating, spin coating, and inkjet methods. Spin coating is preferred.

The drying temperature for the coating film is not particularly limited as long as it is a temperature at which a uniform conductive polymer film is obtained and is equal to or lower than the heat resistance temperature of the substrate, but is in the range of room temperature to 300°C, preferably in the range of room temperature to 250°C, and more preferably in the range of room temperature to 200°C.

The drying atmosphere may be air, an inert gas, a vacuum, or a reduced pressure. From the viewpoint of preventing deterioration of the polymer film, an inert gas such as nitrogen or argon is preferable.

Photograph showing the dissolved or dispersed state of polythiophene P1 in Example 1. Photograph taken in Reference Example 1 in which polythiophene P1 was not completely dissolved or dispersed.

The following examples are given, but the present invention should not be construed as being limited to these examples. Analytical instruments and measurement methods used in the examples are listed below.
[Solubility/dispersibility evaluation]
The conductive polymer liquid compositions produced in the following examples were further evaluated based on the presence or absence of precipitation after stirring with a rotor at room temperature for 10 minutes. Dissolution or dispersion refers to a state in which no sediment is present, and precipitation refers to a state in which sediment is present.
[Surface resistivity measurement]
Apparatus: Mitsubishi Chemical Loresta GP MCP-T600.
[Film thickness measurement]
Apparatus: DEKTAK XT manufactured by BRUKER.
[Conductivity measurement of self-doped conductive polymer]
2 ml of the conductive polymer liquid composition of the present invention was cast onto a 50 mm square alkali-free glass plate and heated on a hot plate at 200° C. for 60 minutes to obtain a conductive polymer film. The thickness was calculated from the film thickness and surface resistance value according to the following formula.

Electrical conductivity [S/cm] = 10 ⁴ / (Surface resistivity [Ω/□] x Film thickness [μm])
Example 1
When 0.1 g of polythiophene obtained based on JP 2019-210356 A [polythiophene consisting of structural units of general formulae (1) and (2) (wherein R ¹ = methyl group, M ¹ = dioctylammonium, m = 2; hereinafter abbreviated as P1)] was added to 9.9 g of a mixed liquid consisting of 90% by weight of ethyl acetate (highly polar organic solvent) and 10% by weight of water and stirred at 20°C for 30 minutes using a magnetic stirrer, polythiophene P1 was dissolved or dispersed, and a conductive polymer liquid composition was obtained. The concentration of the polythiophene in the obtained composition was 1.0% by weight.

The electrical conductivity of the conductive polymer liquid composition obtained in this example was 326 S/cm.

Examples 2 to 11
Mixing was carried out under the same conditions as in Example 1, except that 9.9 g of a mixture consisting of 90 wt % of a highly polar organic solvent and 10 wt % of water shown in Table 1 was used instead of 9.9 g of the mixture consisting of 90 wt % of ethyl acetate as a highly polar organic solvent and 10 wt % of water in Example 1.

In either case, polythiophene P1 was dissolved or dispersed in the mixed liquid, and the conductive polymer liquid composition of the present invention was obtained. The conductivity measurement results of each conductive polymer liquid composition are shown in Table 1.

Example 12
The same procedure as in Example 1 was repeated, except that polythiophene P2 [a polythiophene consisting of structural units represented by the general formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = trioctylammonium, and m = 2)] was used instead of polythiophene P1.

Polythiophene P2 was dissolved or dispersed, and the conductive polymer liquid composition of the present invention was obtained. The conductivity measurement results of the obtained conductive polymer liquid composition are shown in Table 1.

Examples 13 to 15
Mixing was carried out under the same conditions as in Example 12, except that 9.9 g of a mixture consisting of 90 wt % of a highly polar organic solvent and 10 wt % of water shown in Table 1 was used instead of 9.9 g of a mixture consisting of 90 wt % of ethyl acetate and 10 wt % of water, which are highly polar organic solvents.

In either case, polythiophene P2 was dissolved or dispersed in the mixed liquid, and the conductive polymer liquid composition of the present invention was obtained. The results of measuring the electrical conductivity of the obtained conductive polymer liquid composition are shown in Table 1.

Example 16
The same procedures as in Example 1 were carried out except that polythiophene P3 [a polythiophene consisting of structural units of the general formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = di(2-ethylhexyl)ammonium, and m = 2)] was used instead of polythiophene P1 in Example 1.

Polythiophene P3 was dissolved or dispersed, and the conductive polymer liquid composition of the present invention was obtained. The conductivity measurement results of the obtained conductive polymer liquid composition are shown in Table 1.

Examples 17 to 19
Mixing was carried out under the same conditions as in Example 16, except that 9.9 g of a mixture consisting of 90 wt % of a highly polar organic solvent and 10 wt % of water shown in Table 1 was used instead of 9.9 g of the mixture consisting of 90 wt % of ethyl acetate and 10 wt % of water, which are highly polar organic solvents.

In either case, polythiophene P3 was dissolved or dispersed in the mixed liquid, and the conductive polymer liquid composition of the present invention was obtained. The results of measuring the conductivity of the obtained conductive polymer liquid composition are shown in Table 1.

Example 20
The same procedure as in Example 1 was repeated, except that polythiophene P4 [a polythiophene consisting of structural units represented by the general formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = decylammonium, and m = 2)] was used instead of polythiophene P1.

Polythiophene P4 was dissolved or dispersed, and the conductive polymer liquid composition of the present invention was obtained. The conductivity measurement results of the obtained conductive polymer liquid composition are shown in Table 1.

Examples 21 to 23
Mixing was carried out under the same conditions as in Example 20, except that 9.9 g of a mixture consisting of 90 wt % of a highly polar organic solvent and 10 wt % of water shown in Table 1 was used instead of 9.9 g of a mixture consisting of 90 wt % of ethyl acetate and 10 wt % of water, which are highly polar organic solvents.

In either case, polythiophene P4 was dissolved or dispersed in the mixed liquid, and the conductive polymer liquid composition of the present invention was obtained. The results of measuring the conductivity of the obtained conductive polymer liquid composition are shown in Table 1.

Reference example 1
When 0.1 g of polythiophene P1 was added to 9.9 g of ethyl acetate and stirred at 20° C. for 30 minutes, polythiophene P1 was not completely dissolved or dispersed, and some of polythiophene P1 precipitated in the solution. The polythiophene concentration in the solution composition obtained by filtering the insoluble matter was 0.1% by weight.

As described above, according to the present invention, it is possible to produce a high-concentration organic solvent-based conductive polymer solution using an organic solvent, which has been difficult to obtain a high-concentration conductive polymer solution using conventional methods. By using the technology of the present invention, it is possible to provide a high-concentration organic solvent-based conductive polymer composition. The higher the concentration of the conductive polymer, the thicker the conductive polymer film that can be obtained in one film formation operation. Therefore, by using the composition of the present invention, it is possible to reduce the number of recoatings required to obtain the desired film thickness, which is expected to simplify the film formation process and improve work efficiency.

The manufacturing method of the present invention provides a method for industrially producing an organic solvent-based conductive polymer liquid composition.

The organic solvent-based conductive polymer liquid composition of the present invention can be used as an antistatic agent, solid electrolyte for capacitors, antistatic film, solid electrolyte for solid electrolytic capacitors, separator for wound aluminum electrolytic capacitor, etc. It can also be expected to be applied to organic thin-film solar cells, organic electroluminescence, electrochromic elements, transparent electrodes, transparent conductive films, thermoelectric conversion materials, chemical sensors, actuators, electromagnetic wave shielding materials, conductive paints, conductive inks, etc.

Claims (8)

At least the following general formulas (1) and (2)
{In the above general formulas (1) and (2), R ¹ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. ^{M 1} represents an ammonium ion represented by [NH(R ² )(R ³ ) ₂ ] ⁺ , or a quaternary ammonium cation represented by [N(R ² )(R ³ ) ₃ ] ⁺ . R ² represents an alkyl group having 7 to 20 carbon atoms, or an alkyl group having a substituent and a total of 7 to 20 carbon atoms. Each R ³ independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having a substituent and a total of 1 to 20 carbon atoms. m represents an integer of 1 to 6.}
and water, wherein the content of the polythiophene in the obtained conductive polymer liquid composition is 0.1 to 25% by weight, the content of the solvent or the mixed solvent is 50 to 97% by weight, and the content of the water is 3 to 40% by weight (however, the content of the solvent or the mixed solvent does not include a composition in which the total content of the polythiophene, the solvent or the mixed solvent, and the water exceeds 100% by weight) . The method according to claim 1, wherein m is 2 or 3. The method according to claim 1 , wherein R ¹ is a methyl group. At least the following general formulas (1) and (2)
{In the above general formulas (1) and (2), R ¹ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. ^{M 1} represents an ammonium ion represented by [NH(R ² )(R ³ ) ₂ ] ⁺ , or a quaternary ammonium cation represented by [N(R ² )(R ³ ) ₃ ] ⁺ . R ² represents an alkyl group having 7 to 20 carbon atoms, or an alkyl group having a substituent and a total of 7 to 20 carbon atoms. Each R ³ independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having a substituent and a total of 1 to 20 carbon atoms. m represents an integer of 1 to 6.}
a conductive polymer liquid composition comprising a polythiophene having a structural unit represented by the formula: one solvent or a mixed solvent of two or more solvents selected from the group consisting of alcohol solvents, ketone solvents, ether solvents, ester solvents, glycol solvents, glycol ester solvents, glycol ether solvents, glyme solvents, amide solvents, and sulfur-containing solvents, and water, wherein the content of the polythiophene is 0.1 to 25% by weight, the content of the solvent or mixed solvent is 50 to 97% by weight, and the content of the water is 3 to 40% by weight (however, the content of the solvent or mixed solvent does not include a composition in which the total content of the polythiophene, the solvent or mixed solvent, and the water exceeds 100% by weight) . The conductive polymer liquid composition according to claim 4, wherein m is 2 or 3. The conductive polymer liquid composition according to claim 4 , wherein R ¹ is a methyl group. The conductive polymer liquid composition according to claim 4, characterized in that the water content is 5 to 30% by weight. 5. The conductive polymer liquid composition according to claim 4, wherein the liquid composition comprises the polythiophene, the solvent or mixed solvent , and water.