JP7669756B2 - Composition consisting of polythiophene and organic solvent, and use thereof - Google Patents

Description

The present invention relates to a composition comprising a polythiophene that is dispersible or soluble in an organic solvent and an organic solvent, and uses thereof.

Since polythiophene-based self-doped conductive polymers have high conductivity, they are being studied in a wide range of fields, such as solid electrolytic capacitors, antistatic agents, hole injection agents for solar cells, and transparent electrodes. Examples of using organic solvent solutions as solvents for polythiophene-based self-doped conductive polymer solutions in these applications have been reported (e.g., Patent Document 1).

JP 2019-210356 A

When attempts were made to form a film with a thickness in the order of microns using an organic solvent solution of a conductive polymer specifically disclosed in Patent Document 1, it was found that cracks and mottled patterns were likely to occur, making it difficult to form a film with a good yield.

As a result of extensive research, the inventors discovered that by using the composition shown below, it is possible to produce micron-sized films that are less susceptible to cracking or mottling with good yield, and thus completed the present invention.

That is, the present invention resides in the following [1] to [8].
[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 organic 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 solvent (A) having a standard boiling point of 30 to 150°C, and a solvent (B) having a standard boiling point of 150 to 300°C, wherein the content of the polythiophene is 0.01 to 25% by weight, the content of the solvent (A) having a standard boiling point of 30 to 150°C is 50 to 99% by weight, and the content of the solvent (B) having a standard boiling point of 150 to 300°C is 0.5 to 30% by weight.
[2] The composition according to [1], wherein m is 2 or 3.
[3] The composition according to [1], wherein R ¹ is a methyl group.
[4] The composition according to [1], wherein the solvent (A) having a normal boiling point of 30 to 150° C. is one single solvent or a mixed solvent of two or more selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, tert-butyl alcohol, 1-methoxy-2-propanol, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, chlorobenzene, and ethyl acetate.
[5] The composition according to [1], wherein the solvent (B) having a normal boiling point of 150 to 300° C. is one single solvent or a mixed solvent of two or more selected from the group consisting of 1,3-butanediol, 1,4-butanediol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monobutyl ether, ethylene glycol mono-tert-butyl ether, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, γ-butyrolactone, cyclohexanone, dimethylsulfoxide, and glycerin.
[6] A method for producing a conductive polymer film, comprising: applying a conductive polymer composition containing the composition according to [1] onto a support; heating the composition to 40° C. or higher to mainly evaporate the solvent (A); and then increasing the heating temperature to evaporate the solvent (B).

The present invention makes it possible to produce highly conductive coating films at the micron level that are free of cracks and spots with good yield.

When the polythiophene is heated to form a film, the solvents with different boiling points are evaporated in at least two stepwise stages, which acts to suppress segregation and rapid solidification of the polythiophene, and it is presumed that the above-mentioned effects are realized based on this action.

The present invention is described in detail below.

The present invention is a composition comprising a polythiophene containing at least structural units represented by the above general formulas (1) and (2), a solvent (A) having a standard boiling point of 30 to 150°C, and a solvent (B) having a standard boiling point of 150 to 300°C, characterized in that the content of the polythiophene is 0.01 to 25% by weight, the content of the solvent (A) having a standard boiling point of 30 to 150°C is 50 to 99% by weight, and the content of the solvent (B) having a standard boiling point of 150 to 300°C is 0.5 to 30% by weight.

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 alkyl group having 1 to 6 carbon atoms (an alkyl group having 3 to 6 carbon atoms may be linear or branched) 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 halogen atom may be a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or the like.

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.

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

The organic ammonium ion represented by the formula [NH( ^R2 )( ^R3 ) ₂ ] ⁺ is an organic amine compound represented by the formula [N( ^R2 )( ^R3 ) ₂ ] to which a hydron (H ⁺ ) is added to form a cationic species (conjugate acid). The organic amine compound represented by the formula [N( ^R2 )( ^R3 ) ₂ ] reacts with a sulfonic acid group to form an organic ammonium ion (conjugate acid) represented by the formula [NH( ^R2 )( ^R3 ) ₂ ] ⁺ .

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.

Examples of alkyl groups having 7 to 20 carbon atoms (which may be linear or branched) include, but are not limited to, 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 substituted alkyl groups having a total of 7 to 20 carbon atoms (which may be linear or branched) include alkyl groups having a total of 7 to 20 carbon atoms (which may be linear or branched) that have a halogen atom, an amino group, or a hydroxy group, and specific examples include an 8-hydroxyoctyl group and 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 methylheptyl group, a 2-ethylhexyl 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 (an alkyl group having 3 to 20 carbon atoms may be linear or branched), or an alkyl group having a total of 1 to 20 carbon atoms and a substituent (an alkyl group having 3 to 20 carbon atoms may be linear or branched).

Examples of alkyl groups having 1 to 20 carbon atoms (alkyl groups having 3 to 20 carbon atoms may be linear or branched) include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, n- Examples include hexyl group, 2-ethylbutyl group, cyclohexyl group, n-heptyl group, methylhexyl group, n-octyl group, methylheptyl group, ethylhexyl group, n-nonyl group, n-decyl group, ethyloctyl group, butylhexyl group, n-undecyl group, n-dodecyl group, n-hexadecyl group, n-heptadecyl group, octylnonyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, and octyldodecane group.

Examples of substituted alkyl groups having 1 to 20 carbon atoms (alkyl groups having 3 to 20 carbon atoms may be either linear or branched) include alkyl groups having a total of 1 to 20 carbon atoms and having a halogen atom, amino group, or hydroxyl group (alkyl groups having 3 to 20 carbon atoms may be either linear or branched), and specific examples include trifluoromethyl, 2-hydroxyethyl, 8-hydroxyoctyl, and 9-aminononyl groups.

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 methylheptyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, or an n-dodecyl group.

The organic 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, 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-octadecylamine, di-n-octadecylamine, tri-n-octadecylamine, amine, n-icosylamine, di-n-icosylamine, tri-n-icosylamine, 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-diethyl-n-dodecylamine, N,N-diethyl-n-hexadecane 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, ethylheptylamine, ethyloctylamine ethylamine, 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 organic 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, 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, n-octadecylammonium, di-n-octadecylammonium, 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-dodecyl ammonium, N,N-diethyl-n-hexadecyl ammonium n-ethylhexylammonium, 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, ethylheptylammonium, ethyloctylammonium ammonium, 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, or 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 above ^M3 represents an anion, and examples thereof include, but are not limited to, a hydroxyl ion, a chloride ion, a bromide ion, an iodide ion, an acetate ion, a sulfonate ion, a methylsulfonate ion, a benzenesulfonate ion, and a toluenesulfonate 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 the organic amine compound represented by ^{the above-mentioned [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 a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. ^M2 represents a hydrogen ion or an alkali metal ion. m represents an integer of 1 to 6.]
The alkyl group having 1 to 6 carbon atoms (an alkyl group having 3 to 6 carbon atoms may be linear or branched) is not particularly limited, and 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 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, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-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 pansulfonate 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.

The solvent (A) having a standard boiling point of 30 to 150°C is not particularly limited, but examples thereof include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, tert-butyl alcohol, benzene, toluene, xylene, acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, 1,4-dioxane, methyl acetate, ethyl acetate, butyl acetate, methyl lactate, 1-methoxy-2-propanol, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, chloroform, dichloromethane, 1,2-dichloroethane, chlorobenzene, tetrahydrofuran, and water.

These solvents may be used alone or in combination of two or more.

The solvent (A) having a standard boiling point of 30 to 150°C is preferably one single solvent or two or more mixed solvents selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, tert-butyl alcohol, 1-methoxy-2-propanol, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, chlorobenzene, and ethyl acetate, in terms of excellent film-forming properties, and more preferably one single solvent or two or more mixed solvents selected from the group consisting of methanol, ethanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, 1-methoxy-2-propanol, methyl ethyl ketone, methyl isobutyl ketone, and ethyl acetate.

The solvent (B) having a standard boiling point of 150 to 300°C is not particularly limited, but examples thereof include 1,3-butanediol, 1,4-butanediol, 2-ethylhexanol, benzyl alcohol, diisobutyl ketone, diacetone alcohol, cyclohexanone, butyl cellosolve, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, methyl carbitol, ethyl carbitol, butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monohexyl ether, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylimidazolidinone, hexamethylphosphoric triamide, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and glycerin.

These solvents may be used alone or in combination of two or more.

Regarding the solvent (B) having a standard boiling point of 150 to 300°C, in terms of excellent film-forming properties, the following are recommended: 1,3-butanediol, 1,4-butanediol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monobutyl ether, ethylene glycol mono-tert-butyl ether, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, γ-butyrolactone, cyclohexanone, It is preferable that the solvent is a single solvent or a mixed solvent of two or more selected from the group consisting of dimethyl sulfoxide and glycerin, and it is more preferable that the solvent is a single solvent or a mixed solvent of two or more selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monobutyl ether, ethylene glycol mono-tert-butyl ether, ethylene glycol monohexyl ether, dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidone, dimethyl sulfoxide, and glycerin.

The composition of the present invention is
The content of the polythiophene is 0.01 to 25% by weight, the content of the solvent (A) having a standard boiling point of 30 to 150° C. is 50 to 99% by weight, and the content of the solvent (B) having a standard boiling point of 150 to 300° C. is 0.5 to 30% by weight. The present invention is characterized in that the ...
It is preferable that the content of the polythiophene is 0.01 to 15% by weight, the content of the solvent (A) having a standard boiling point of 30 to 150° C. is 60 to 99% by weight, and the content of the solvent (B) having a standard boiling point of 150 to 300° C. is 0.5 to 25% by weight,
More preferably, the content of the polythiophene is 0.01 to 10% by weight, the content of the solvent (A) having a standard boiling point of 30 to 150° C. is 70 to 99% by weight, and the content of the solvent (B) having a standard boiling point of 150 to 300° C. is 0.5 to 20% by weight;
It is more preferable that the content of the polythiophene is 0.01 to 5% by weight, the content of the solvent (A) having a normal boiling point of 30 to 150° C. is 80 to 99% by weight, and the content of the solvent (B) having a normal boiling point of 150 to 300° C. is 0.5 to 15% by weight.

The composition of the present invention can be produced by mixing the polythiophene, the solvent (A) having a standard boiling point of 30 to 150°C, and the solvent (B) having a standard boiling point of 150 to 300°C.

When mixing the composition of the present invention, in addition to general mixing and dissolving operations using stirrer tips, stirring blades, etc., ultrasonic irradiation or homogenization treatment (e.g., use of a mechanical homogenizer, ultrasonic homogenizer, high-pressure homogenizer, etc.) may be performed.

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 mixing 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.

The composition of the present invention can be applied to a support, then heated to 40°C or higher to evaporate mainly the solvent (A), and then the heating temperature is increased to evaporate mainly the solvent (B), thereby producing a conductive polymer film with a good thickness at the micron level.

The support is not particularly limited as long as it is one to which the composition of the present invention can be applied, and examples thereof include polymeric substrates and inorganic substrates. More specifically, examples thereof include thermoplastic resins, nonwoven fabrics, and paper. Examples of thermoplastic resins include polyethylene, polypropylene, polyethylene terephthalate, polyacrylate, and polycarbonate. Examples of nonwoven fabrics may be either natural fibers or synthetic fibers. Examples of paper may be those mainly composed of general cellulose. Examples of other inorganic substrates are not particularly limited, and examples thereof include glass, glass fibers, ceramics, aluminum oxide, and tantalum oxide.

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

The temperature at which the solvent (A) is primarily evaporated is preferably in the range of 40°C to 150°C, more preferably in the range of 80°C to 140°C, and even more preferably in the range of 100°C to 130°C, in order to produce a conductive polymer film of higher quality.

The heat treatment time for mainly evaporating the solvent (A) is not particularly limited, but is preferably in the range of 5 to 120 minutes, more preferably 15 to 90 minutes, in order to produce a conductive polymer film of higher quality.

The temperature at which the solvent (B) is primarily evaporated is preferably in the range of 120°C to 300°C, more preferably in the range of 140°C to 260°C, and even more preferably in the range of 160°C to 240°C, in order to produce a conductive polymer film of higher quality.

The heat treatment time for mainly evaporating the solvent (B) is not particularly limited, but is preferably in the range of 5 to 240 minutes, more preferably in the range of 15 to 180 minutes, in order to produce a conductive polymer film of higher quality.

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.

When forming a film from the composition of the present invention, additives can be added to the composition as appropriate. The additives are not particularly limited, but examples thereof include polyhydric alcohol compounds, surfactants, binder resins, crosslinking agents, lubricants, etc.

The polyhydric alcohol compound is not particularly limited, but examples thereof include erythritol, sorbitol, mannitol, xylitol, and arabitol. Of these, sorbitol is preferred.

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.

The polymeric nonionic surfactant is not particularly limited, but examples thereof include polyvinylpyrrolidone and copolymers of polyvinylpyrrolidone. 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. For example, 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 can be mentioned.

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.

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, and polyvinyl alcohol resin.

The crosslinking agent is not particularly limited, but examples thereof include aminopropyltrimethoxysilane, epoxypropyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, propyltriethoxysilane, aminopropyltriethoxysilane, epoxypropyltriethoxysilane, and 3-glycidyloxypropyltriethoxysilane. Of these, 3-glycidyloxypropyltrimethoxysilane and 3-glycidyloxypropyltriethoxysilane are preferred in terms of excellent film-forming properties.

The lubricant mentioned above refers 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 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 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), silicone oil, and silicone powder.

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

Photograph showing the state of a polythiophene film formed in Example 1 using a composition consisting of polythiophene, a solvent (A) having a normal boiling point of 30 to 150° C., and a solvent (B) having a normal boiling point of 150 to 300° C. Photograph showing the state of a polythiophene film formed in Reference Example 1 using a composition consisting of polythiophene and a solvent (A) having a boiling point of 30 to 150° C.

The following examples are given, but the present invention should not be construed as being limited to these examples. Measurement methods used in the examples are listed below.
[Film formation method]
A film was obtained by casting 2 ml of the composition shown in the following Examples on a 50 mm square non-alkali glass plate and heating it at 120° C. for 30 minutes and at 200° C. for 60 minutes. Regarding the film-forming property, a state in which no cracks were observed by visual inspection was designated as "good film-forming property".
[Film thickness measurement]
Apparatus: DEKTAK XT manufactured by BRUKER.

Example 1
0.1 g of a solid polythiophene [polythiophene consisting of structural units of the above formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = dioctylammonium, m = 2; hereinafter abbreviated as P1)] obtained based on JP 2019-210356 A was added to 9.9 g of a mixed solution consisting of 90% by weight of 1-butanol and 10% by weight of ethylene glycol, and the mixture was stirred at 20°C for 30 minutes to obtain a composition of the present invention. After that, a film was formed under the conditions of the above-mentioned film formation method, and a conductive polymer film with good film formability was obtained.

Examples 2 to 17
A composition of the present invention was obtained by mixing and stirring under the same conditions as in Example 1, except that 9.9 g of a mixed solution having the composition shown in Table 1 was used instead of 9.9 g of a mixed solution consisting of 90% by weight of 1-butanol and 10% by weight of ethylene glycol in Example 1, and a film formation test was performed. In each case, a conductive polymer film with good film formability was obtained.

Example 18
The same conditions as in Example 1 were used except that 0.1 g of a solid polythiophene P2 [a polythiophene consisting of structural units of the above formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = trioctylammonium, m = 2)] was used instead of 0.1 g of a solid polythiophene P1 in Example 1. When a film was formed by the above film formation method, a polythiophene film with good film formability was obtained.

Examples 19 to 34
A composition of the present invention was obtained by mixing and stirring under the same conditions as in Example 19, except that 9.9 g of a mixture having the composition shown in Table 2 was used instead of 9.9 g of a mixture consisting of 90% by weight of 1-butanol and 10% by weight of ethylene glycol in Example 18, and a film formation test was performed. In each case, a conductive polymer film with good film formability was obtained.

Example 35
The same conditions as in Example 1 were used except that 0.1 g of a solid polythiophene P3 [a polythiophene consisting of structural units of the above formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = di(2-ethylhexyl)ammonium, m = 2)] was used instead of 0.1 g of a solid polythiophene P1 in Example 1. When a film was formed by the above film formation method, a conductive polymer film with good film formability was obtained.

Examples 36 to 51
A composition of the present invention was obtained by mixing and stirring under the same conditions as in Example 35, except that 9.9 g of a mixed solution having the composition shown in Table 3 was used instead of 9.9 g of a mixed solution consisting of 90% by weight of 1-butanol and 10% by weight of ethylene glycol in Example 35, and a film formation test was performed. In each case, a conductive polymer film with good film formability was obtained.

Example 52
The same conditions as in Example 1 were used except that 0.1 g of a solid polythiophene P4 [a polythiophene consisting of structural units of the above formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = decylammonium, and m = 2)] was used instead of 0.1 g of a solid polythiophene P1 in Example 1. When a film was formed by the above film formation method, a conductive polymer film with good film formability was obtained.

Examples 53 to 68
A composition of the present invention was obtained by mixing and stirring under the same conditions as in Example 52, except that 9.9 g of a mixed solution having the composition shown in Table 4 was used instead of 9.9 g of a mixed solution consisting of 90% by weight of 1-butanol and 10% by weight of ethylene glycol in Example 52, and a film formation test was performed. In each case, a conductive polymer film with good film formability was obtained.

Comparative Example 1
0.1 g of a solid polythiophene P1 [polythiophene consisting of structural units of the above formulas (1) and (2) (wherein R ¹ = methyl group, M ¹ = dioctylammonium, m = 2)] was added to 9.9 g of 1-butanol and stirred at 20° C. for 30 minutes to obtain a composition. When a film was then formed by the above-mentioned film formation method, a conductive polymer film with cracks was obtained.

The composition of the present invention, which is composed of the above polythiophene, a solvent (A) having a boiling point of 30 to 150°C, and a solvent (B) having a boiling point of 150 to 300°C, has good film-forming properties and can be used as an antistatic agent, a solid electrolyte for capacitors, as well as an antistatic film, a solid electrolyte for solid electrolytic capacitors, and a separator for wound-type aluminum electrolytic capacitors. In addition, it can be expected to be used in organic thin-film solar cells, organic electroluminescence, electrochromic elements, transparent electrodes, transparent conductive films, thermoelectric conversion materials, chemical sensors, actuators, electromagnetic shielding materials, conductive paints, conductive inks, etc.

Claims (6)

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 organic 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 a solvent (A) having a standard boiling point of 30 to 150° C. [However, the solvent of the solvent (A) does not include water. and a solvent (B) having a standard boiling point of 150 to 300°C, wherein the content of the polythiophene is 0.01 to 25% by weight, the content of the solvent (A) having a standard boiling point of 30 to 150°C is 50 to 99% by weight, and the content of the solvent (B) having a standard boiling point of 150 to 300°C is 0.5 to 30% by weight. The composition of claim 1, wherein m is 2 or 3. The composition of claim 1 , wherein R ¹ is a methyl group. The composition according to claim 1, wherein the solvent (A) having a standard boiling point of 30 to 150°C is one single solvent or a mixed solvent of two or more selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, tert-butyl alcohol, 1-methoxy-2-propanol, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, chlorobenzene, and ethyl acetate. The composition according to claim 1, wherein the solvent (B) having a standard boiling point of 150 to 300°C is one single solvent or a mixed solvent of two or more selected from the group consisting of 1,3-butanediol, 1,4-butanediol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, ethylene glycol monobutyl ether, ethylene glycol mono-tert-butyl ether, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, γ-butyrolactone, cyclohexanone, dimethylsulfoxide, and glycerin. A method for producing a conductive polymer film, comprising: applying a conductive polymer composition containing the composition according to claim 1 onto a support; heating the composition to 40°C or higher to mainly evaporate the solvent (A); and then increasing the heating temperature to evaporate the solvent (B).