Conductive polymer-containing liquid, conductive film, and method for producing the same

Abstract

To provide a conductive film having suppressed temporal conductivity lowering with time in air and having excellent conductivity, a method for easily manufacturing the same, as well as, a conductive polymer-containing liquid used in the manufacturing method.SOLUTION: A conductive polymer-containing liquid contains: a conductive composite containing a π-conjugated conductive polymer and a polyanion; water; a low-boiling organic solvent with a boiling point of less than 150°C; a high-boiling point solvent with a boiling point of 150°C or more; an emulsion resin; an antioxidant; and a curing agent having an aziridinyl group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a conductive polymer-containing liquid, a conductive film, and a method for producing the same. [Background technology]

[0002] A π-conjugated conductive polymer whose main chain is composed of a π-conjugated system forms a conductive complex by doping with a polyanion having an anionic group, and becomes dispersible in water. A conductive film having a conductive layer can be produced by applying a conductive polymer-containing liquid (sometimes called a conductive polymer dispersion) containing the conductive complex to a film substrate or the like. However, a conductive layer containing the conductive complex has a problem in that its conductivity decreases over time when exposed to the atmosphere. To alleviate this problem, a method of incorporating a specific compound into the conductive layer has been disclosed (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-143202 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need for a new additive that can replace the specific antioxidant described in Patent Document 1 and that suppresses the decrease in conductivity over time due to exposure to the atmosphere.

[0005] The present invention provides a conductive film that exhibits good conductivity and is inhibited from decreasing in conductivity over time in the atmosphere, a method for easily producing the same, and a conductive polymer-containing liquid to be used in the production method. [Means for solving the problem]

[0006] [1] A conductive polymer-containing liquid containing a conductive complex containing a π-conjugated conductive polymer and a polyanion, water, a low-boiling organic solvent having a boiling point of less than 150°C, a high-boiling solvent having a boiling point of 150°C or more, an emulsion resin, an antioxidant, and a curing agent having an aziridinyl group. [2] The conductive polymer-containing liquid according to [1], wherein the curing agent has two or more aziridinyl groups in the molecule. [3] The conductive polymer-containing liquid according to [1] or [2], wherein the curing agent has one or more of the formula (f1) described below in the molecule. [4] The conductive polymer-containing liquid according to any one of [1] to [3], wherein the curing agent is a compound represented by the formula (1) described below. [5] The conductive polymer-containing liquid according to any one of [1] to [4], wherein the emulsion resin is a polyester having a sulfo group in the molecule. [6] The conductive polymer-containing liquid according to [5], wherein the polyester has a polyethylene naphthalate skeleton. [7] The conductive polymer-containing liquid according to any one of [1] to [6], wherein the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene) or the polyanion is polystyrene sulfonic acid. [8] The conductive polymer-containing liquid according to any one of [1] to [7], wherein the content of the curing agent is 10 parts by mass or more and 300 parts by mass or less when the total content of the π-conjugated conductive polymer and the polyanion is 100 parts by mass. [9] A conductive film comprising a film substrate and a conductive layer formed on at least a portion of the surface of the film substrate, the conductive layer being a cured product of the conductive polymer-containing liquid according to any one of [1] to [8].

[10] A method for producing a conductive film, comprising a step of applying the conductive polymer-containing liquid according to any one of [1] to [8] to at least a part of the surface of a film substrate. [Effects of the Invention]

[0007] According to the conductive polymer-containing liquid of the present invention and the method for producing a conductive film using the same, a decrease in conductivity over time in the atmosphere is suppressed, and a conductive film having a conductive layer with good conductivity can be easily produced. Furthermore, the conductive layer of the conductive film according to the present invention also has excellent solvent resistance.

[0008] This invention is believed to contribute to SDG Goal 12, "Responsible Consumption and Production."

[0009] In this specification and claims, the lower and upper limits of numerical ranges indicated with "to" are included in the numerical range. DETAILED DESCRIPTION OF THE INVENTION

[0010] ≪Conductive polymer-containing liquid≫ The conductive polymer-containing liquid of the first aspect of the present invention contains a conductive composite containing a π-conjugated conductive polymer and a polyanion, water, a low-boiling organic solvent having a boiling point of less than 150°C, a high-boiling solvent having a boiling point of 150°C or higher, an emulsified resin, an antioxidant, and a curing agent having an aziridinyl group. In the conductive polymer-containing liquid of the present invention, the conductive complex may be in a dispersed state or a dissolved state.

[0011] [Conductive composite] The conductive composite in this embodiment contains a π-conjugated conductive polymer and a polyanion. The polyanion in the conductive composite dopes the π-conjugated conductive polymer to form a conductive composite having conductivity.

[0012] (π-conjugated conductive polymer) The π-conjugated conductive polymer may be an organic polymer whose main chain is composed of a π-conjugated system, and examples thereof include polypyrrole-based conductive polymers, polythiophene-based conductive polymers, polyacetylene-based conductive polymers, polyphenylene-based conductive polymers, polyphenylene vinylene-based conductive polymers, polyaniline-based conductive polymers, polyacene-based conductive polymers, polythiophene vinylene-based conductive polymers, and copolymers thereof. From the viewpoint of stability in air, polypyrrole-based conductive polymers, polythiophenes, and polyaniline-based conductive polymers are preferred, and from the viewpoint of transparency, polythiophene-based conductive polymers are more preferred.

[0013] Polythiophene-based conductive polymers include polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly(3-bromothiophene), poly(3-chlorothiophene), and poly(3-iodothiophene). thiophene), poly(3-cyanothiophene), poly(3-phenylthiophene), poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly(3-heptyloxythiophene), poly(3-octyloxythiophene), poly(3-decyloxythiophene), poly(3-dodecyloxythiophene) oxythiophene), poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene), poly(3,4-dimethoxythiophene), poly(3,4-diethoxythiophene), poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene), poly(3,4-dihexyloxythiophene), poly(3,4-diheptyloxythiophene), poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene), poly(3,4-di dodecyloxythiophene), poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butylenedioxythiophene), poly(3-methyl-4-methoxythiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), and poly(3-methyl-4-carboxybutylthiophene). Examples of polypyrrole-based conductive polymers include polypyrrole, poly(N-methylpyrrole), poly(3-methylpyrrole), poly(3-ethylpyrrole), poly(3-n-propylpyrrole), poly(3-butylpyrrole), poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3-dodecylpyrrole), poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole), poly(3-carboxypyrrole), poly(3-methyl-4-carboxypyrrole), poly(3-methyl-4-carboxyethylpyrrole), poly(3-methyl-4-carboxybutylpyrrole), poly(3-hydroxypyrrole), poly(3-methoxypyrrole), poly(3-ethoxypyrrole), poly(3-butoxypyrrole), poly(3-hexyloxypyrrole), and poly(3-methyl-4-hexyloxypyrrole). Examples of polyaniline-based conductive polymers include polyaniline, poly(2-methylaniline), poly(3-isobutylaniline), poly(2-anilinesulfonic acid), and poly(3-anilinesulfonic acid). Among these π-conjugated conductive polymers, poly(3,4-ethylenedioxythiophene) is particularly preferable in terms of conductivity, transparency, and heat resistance. The conductive composite may contain one type of π-conjugated conductive polymer, or two or more types of polymers.

[0014] (polyanion) A polyanion is a polymer having two or more monomer units with an anionic group in the molecule. The anionic group of this polyanion functions as a dopant for a π-conjugated conductive polymer, improving the conductivity of the π-conjugated conductive polymer. The anionic group of the polyanion is preferably a sulfo group or a carboxy group. Specific examples of such polyanions include polymers having sulfo groups, such as polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacrylic acid esters having sulfo groups, polymethacrylic acid esters having sulfo groups (for example, poly(4-sulfobutyl methacrylate, polysulfoethyl methacrylate, polymethacryloyloxybenzenesulfonic acid), poly(2-acrylamido-2-methylpropanesulfonic acid), and polyisoprene sulfonic acid; and polymers having carboxy groups, such as polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacrylic acid, polymethacrylic acid, poly(2-acrylamido-2-methylpropanecarboxylic acid), and polyisoprene carboxylic acid. The polyanion may be a homopolymer formed by polymerizing a single monomer, or a copolymer formed by polymerizing two or more types of monomers. Among these polyanions, polymers having sulfo groups are preferred, and polystyrene sulfonic acid is more preferred, since they can further increase the conductivity. The polyanions may be used alone or in combination of two or more. The mass-average molecular weight of the polyanion is preferably 20,000 to 1,000,000, more preferably 100,000 to 500,000. The mass-average molecular weight is the average molecular weight based on mass measured using gel permeation chromatography and calculated in terms of polystyrene.

[0015] The content of the polyanion in the conductive composite is preferably in the range of 1 part by mass to 1,000 parts by mass, more preferably 10 parts by mass to 700 parts by mass, and even more preferably 100 parts by mass to 500 parts by mass, per 100 parts by mass of the π-conjugated conductive polymer. If the content of the polyanion is equal to or greater than the lower limit, the doping effect on the π-conjugated conductive polymer tends to be stronger, resulting in higher conductivity. On the other hand, if the content of the polyanion is equal to or less than the upper limit, the π-conjugated conductive polymer can be sufficiently contained, thereby ensuring sufficient conductivity.

[0016] In the polyanion in the conductive composite, not all of the anionic groups are doped into the π-conjugated conductive polymer, and there are excess anionic groups that are not involved in the doping. These excess anionic groups are hydrophilic groups, and the dispersibility of the conductive composite with no anionic group modification is high in aqueous dispersion media but low in organic solvents.

[0017] (Conductive complex content) From the viewpoint of enhancing dispersibility, the content of the conductive complex relative to the total mass of the conductive polymer-containing liquid of this embodiment is, for example, preferably 0.001 mass % or more and 0.5 mass % or less, more preferably 0.005 mass % or more and 0.2 mass % or less, and even more preferably 0.01 mass % or more and 0.1 mass % or less.

[0018] [Hardening agent] The curing agent of this embodiment has an aziridinyl group. Here, the aziridinyl group refers to a monovalent group obtained by removing the proton bonded to the nitrogen atom of aziridine. The aziridinyl group is highly reactive and can undergo ring opening to bond with a carboxyl group or a sulfo group. Although the detailed mechanism is not yet clear, the inclusion of this curing agent improves the atmospheric exposure resistance of the conductive layer, which is the cured product of the conductive polymer-containing liquid of this embodiment.

[0019] The curing agent of this embodiment preferably has two or more aziridinyl groups in the molecule, which allows the curing agent to function as a crosslinking agent. The curing agent of this embodiment preferably has one or more functional groups (f1) represented by the following formula (f1) in the molecule.

[0020] [ka]

[0021] The functional group (f1) is a monovalent group in which one amino group of urea is replaced with an aziridinyl group and one proton of the other amino group is removed. The functional group (f1) has low reactivity with carboxyl groups and sulfo groups, making it easier to handle the conductive polymer-containing liquid containing the curing agent.

[0022] The curing agent of this embodiment is preferably a compound (1) represented by the following formula (1). Because the molecule has two benzene rings, the molecular structure is relatively rigid. This increases the structural strength of the conductive layer, which is the cured product of the conductive polymer-containing liquid of this embodiment, and improves its scratch resistance.

[0023] [ka]

[0024] The content of the curing agent contained in the conductive polymer-containing liquid of this embodiment is preferably 10 parts by mass or more and 1,000 parts by mass or less, more preferably 15 parts by mass or more and 500 parts by mass or less, even more preferably 20 parts by mass or more and 300 parts by mass or less, and particularly preferably 25 parts by mass or more and 200 parts by mass or less, relative to 100 parts by mass of the conductive composite (i.e., relative to a total of 100 parts by mass of the π-conjugated conductive polymer and the polyanion). When the content of compound (1) is within the above range, the resistance to atmospheric exposure and the solvent resistance can be further improved without significantly impairing the conductivity of the conductive layer.

[0025] The content of the curing agent contained in the conductive polymer-containing liquid of this embodiment is preferably 2 parts by mass or more and 100 parts by mass or less, more preferably 4 parts by mass or more and 60 parts by mass or less, even more preferably 7 parts by mass or more and 30 parts by mass or less, and particularly preferably 9 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the emulsion resin described below. When the content of compound (1) is within the above range, the resistance to exposure to the atmosphere and the solvent resistance of the conductive layer can be further improved.

[0026] (water) The conductive polymer-containing liquid of this embodiment contains water. Water can disperse or dissolve the conductive composite, so it can be called a dispersion medium or a solvent. In this specification, the term "dispersion" may be used without distinguishing between dispersion and dissolution, and the term "dispersion medium" may be used without distinguishing between a dispersion medium and a solvent.

[0027] The content of water relative to the total mass of water and the low-boiling point solvent contained in the conductive polymer-containing liquid of this embodiment is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less. When the content is at least as large as the lower limit of the above range, the dispersibility of the conductive composite can be improved. When the content is equal to or less than the upper limit of the above range, the dispersibility of the curing agent can be improved.

[0028] The water content relative to the total mass of the conductive polymer-containing liquid of this embodiment is preferably 20% by mass to 80% by mass, more preferably 30% by mass to 70% by mass, and even more preferably 40% by mass to 60% by mass. When the content is at least as large as the lower limit of the above range, the dispersibility of the conductive composite can be improved. When the content is equal to or less than the upper limit of the above range, there is more room for adding components other than the conductive composite.

[0029] (low boiling point solvent) The low-boiling point solvent of this embodiment is an organic solvent having a boiling point of less than 150° C. at 1 atmosphere (101,325 Pascals). The boiling point is preferably 30° C. or higher and 100° C. or lower. By including a low-boiling point solvent, the dispersibility of the curing agent can be improved. The conductive polymer-containing liquid of this embodiment may contain one type of low-boiling point solvent, or two or more types of low-boiling point solvents.

[0030] The low-boiling point solvent may be a water-soluble organic solvent, a water-insoluble organic solvent, or a mixed solvent of a water-soluble organic solvent and a water-insoluble organic solvent, but is preferably a water-soluble organic solvent from the viewpoint of preventing phase separation of the conductive polymer-containing liquid of this embodiment. Here, the water-soluble organic solvent is an organic solvent that dissolves in an amount of 1 g or more in 100 g of water at 20°C, and the water-insoluble organic solvent is an organic solvent that dissolves in an amount of less than 1 g in 100 g of water at 20°C.

[0031] Examples of the water-soluble organic solvent include alcohol-based solvents, ether-based solvents, and ketone-based solvents. Examples of alcohol-based solvents include methanol, ethanol, 1-propanol, 2-propanol (isopropanol), 2-methyl-2-propanol (tert-butyl alcohol), 1-butanol, and 2-butanol. Examples of the ether solvent include diethyl ether and dimethyl ether. Examples of ketone solvents include diethyl ketone, methyl propyl ketone, methyl butyl ketone, methyl ethyl ketone, and acetone. The water-soluble organic solvents may be used alone or in combination of two or more. The water-soluble organic solvent is preferably an alcohol-based solvent or a ketone-based solvent, as this improves the coating properties of the conductive polymer-containing liquid on the film substrate.

[0032] Examples of the non-water-soluble organic solvent include hydrocarbon solvents, etc. Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents. Examples of the aliphatic hydrocarbon solvent include hexane, cyclohexane, pentane, heptane, and octane. Examples of aromatic hydrocarbon solvents include benzene, toluene, and xylene.

[0033] The content of the low-boiling point solvent relative to the total mass of water and the low-boiling point solvent contained in the conductive polymer-containing liquid of this embodiment is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less. When the content is at least as large as the lower limit of the above range, the dispersibility of the curing agent can be improved. When the content is equal to or less than the upper limit of the above range, the dispersibility of the conductive composite can be improved.

[0034] The content of the low boiling point solvent relative to the total mass of the conductive polymer-containing liquid of this embodiment is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less. When the content is at least as large as the lower limit of the above range, the dispersibility of the curing agent can be improved. When the content is equal to or less than the upper limit of the above range, the dispersibility of the conductive composite can be improved.

[0035] (High boiling point solvent) The high-boiling point solvent of this embodiment is an organic solvent having a boiling point of 150° C. or higher at 1 atmosphere (101,325 Pascals). Its boiling point is preferably 250° C. or lower. By including a high-boiling point solvent, effects such as improved conductivity can be obtained. The conductive polymer-containing liquid of this embodiment may contain one type of high-boiling point solvent, or two or more types of high-boiling point solvents.

[0036] Examples of high-boiling point solvents include water-soluble organic solvents and water-insoluble organic solvents, where the definitions of water-soluble organic solvents and water-insoluble organic solvents are the same as those described above.

[0037] Examples of high-boiling water-soluble organic solvents include alcohol-based solvents, ether-based solvents, ketone-based solvents, nitrogen-atom-containing solvents, and sulfur-atom-containing solvents. Examples of alcohol-based solvents include polyhydric alcohols such as ethylene glycol (boiling point 198°C), 1,2-propanediol (also known as propylene glycol, boiling point 188°C), 1,3-propanediol (boiling point 214°C), 1,2-butanediol (boiling point 194°C), 1,3-butanediol (boiling point 207°C), 1,4-butanediol (boiling point 228°C), dipropylene glycol (boiling point 232°C, mixture of isomers), and diethylene glycol (boiling point 245°C). Examples of ether solvents include diethylene glycol dimethyl ether (boiling point 162°C) and diethylene glycol diethyl ether (boiling point 188°C). Examples of ketone solvents include methyl amyl ketone (boiling point 151°C) and diacetone alcohol (boiling point 168°C). Examples of nitrogen atom-containing solvents include N-methylpyrrolidone (boiling point 202°C), N-methylacetamide (boiling point 206°C), dimethylacetamide (boiling point 165°C), and N,N-dimethylformamide (boiling point 153°C). An example of the sulfur atom-containing solvent is dimethyl sulfoxide (boiling point: 189° C.).

[0038] Examples of the high-boiling point water-insoluble organic solvent include hydrocarbon solvents, etc. Examples of the hydrocarbon solvent include aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents. Examples of the aliphatic hydrocarbon solvent include nonane (boiling point 151° C.), decane (boiling point 174° C.), and dodecane (boiling point 216° C.). Examples of aromatic hydrocarbon solvents include propylbenzene (boiling point 159°C) and isopropylbenzene (boiling point 152°C).

[0039] Among the above examples, alcohol-based high-boiling point solvents are preferred because they provide a greater effect of improving conductivity. Among alcohol-based high-boiling point solvents, ethylene glycol (boiling point 198°C), 1,2-propanediol (boiling point 188°C), 1,3-propanediol (boiling point 214°C), and dimethyl sulfoxide (boiling point 189°C) are preferred because of their excellent effects in improving conductivity, and ethylene glycol, 1,2-propanediol, and 1,3-propanediol are more preferred.

[0040] The content of the high-boiling point solvent relative to 100 parts by mass of the conductive composite contained in the conductive polymer-containing liquid of this embodiment is preferably 100 parts by mass or more and 8000 parts by mass or less, more preferably 1000 parts by mass or more and 5000 parts by mass or less, and even more preferably 2000 parts by mass or more and 4000 parts by mass or less. Within this range, the conductivity of the formed conductive layer is further improved.

[0041] The content of the high-boiling point solvent relative to the total mass of the conductive polymer-containing liquid in this embodiment is preferably 0.1% by mass to 10% by mass, more preferably 0.3% by mass to 5% by mass, and even more preferably 0.6% by mass to 2% by mass. Within this range, the conductivity of the formed conductive layer is further improved.

[0042] The ratio of the high-boiling solvent to the low-boiling solvent in the conductive polymer-containing liquid of this embodiment is preferably such that the total mass of the high-boiling solvents (M1) is less than the total mass of the low-boiling solvents (M2). The M2 / M1 ratio is preferably 10 to 100, more preferably 30 to 80, and even more preferably 50 to 70. When the ratio is within the above range, the conductivity of the conductive layer formed can be further increased.

[0043] (emulsion resin) The emulsion resin of this embodiment is a resin that can be emulsified in water. Here, "emulsified" refers to an emulsified state in which an oil-based emulsion resin is stably dispersed in a dispersion medium containing water. The emulsion resin can function as a binder component that maintains the structural strength and holds other components in the conductive layer formed after curing the conductive polymer-containing liquid of this embodiment. The emulsion resin may be used alone or in combination of two or more kinds.

[0044] Specific examples of emulsion resins include polyester resins, polyurethane resins, polyimide resins, melamine resins, and acrylic resins (acrylic compounds), which are emulsified with an emulsifier. Among these, polyester emulsions are preferred because they increase the strength of the coating film formed by applying the conductive polymer-containing liquid to a film substrate. In particular, when applying the conductive polymer-containing liquid to a polyester film substrate, polyester emulsions are preferred because they increase the adhesion of the coating film to the film substrate.

[0045] Since the emulsion resin can be crosslinked by the curing agent, it preferably has an acid group such as a carboxy group or a sulfo group. Furthermore, since the emulsion resin has an acid group, it can be emulsified or dispersed in water without the coexistence of another emulsifier or with a small amount of another emulsifier. The acid group may form a salt with a cation such as a sodium ion or a potassium ion.

[0046] The main chain of the emulsion resin preferably has a polyethylene naphthalate skeleton. The naphthalene ring provides a rigid molecular structure. This increases the structural strength of the conductive layer, which is a cured product of the conductive polymer-containing liquid of this embodiment, and improves its abrasion resistance.

[0047] The weight average molecular weight of the emulsion resin is preferably from 5,000 to 100,000, more preferably from 10,000 to 70,000, and even more preferably from 20,000 to 40,000. When the content is at least the lower limit of the above range, the function as a binder component is more easily exhibited. When the content is equal to or less than the upper limit of the above range, the dispersibility of the emulsion resin in the conductive polymer-containing liquid is further improved. Here, the weight average molecular weight of the emulsion resin is measured using gel permeation chromatography and is the average molecular weight based on mass calculated in terms of polystyrene.

[0048] The total content of emulsion resins contained in the conductive polymer-containing liquid of this embodiment is preferably 200 parts by mass or more and 3000 parts by mass or less, more preferably 500 parts by mass or more and 2000 parts by mass or less, and even more preferably 800 parts by mass or more and 1500 parts by mass or less, per 100 parts by mass of the conductive composite (i.e., per 100 parts by mass of the π-conjugated conductive polymer and polyanion in total). When the content of the emulsion resin is within the above range, the resistance to exposure to the atmosphere and the solvent resistance of the conductive layer can be further improved.

[0049] (antioxidant) The conductive polymer-containing liquid of this embodiment contains an antioxidant, which has the function of preventing oxidative degradation of the conductive composite. Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, sugars, etc. One type of antioxidant may be used alone, or two or more types may be used in combination. Among the antioxidants, gallic acid (gallic acid) or gallic acid esters, which are phenolic antioxidants, are preferred. Examples of gallic acid esters include methyl gallate and ethyl gallate. Gallic acid and gallic acid esters exhibit high antioxidant performance and also have the effect of improving electrical conductivity.

[0050] The content of the antioxidant in the conductive polymer-containing liquid of this embodiment is preferably 1 part by mass or more and 1,000 parts by mass or less, more preferably 10 parts by mass or more and 500 parts by mass or less, and even more preferably 30 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the conductive composite (i.e., relative to a total of 100 parts by mass of the π-conjugated conductive polymer and polyanion). When the content of the antioxidant is at least the lower limit of the above range, the resistance of the conductive layer to exposure to the atmosphere can be further improved, and when it is at most the upper limit, the decrease in conductivity due to the relatively small amount of the conductive complex can be suppressed.

[0051] (Other additives) The conductive polymer-containing liquid may contain other additives. The additives are not particularly limited as long as they can achieve the effects of the present invention, and examples thereof include surfactants, inorganic conductive agents, antifoaming agents, coupling agents, antioxidants, and ultraviolet absorbers. However, the additives are other than the above-mentioned π-conjugated conductive polymer, polyanion, dispersion medium, compound (1), binder component, and conductivity-enhancing agent. The surfactant may be a nonionic, anionic, or cationic surfactant, with the nonionic surfactant being preferred from the standpoint of storage stability. A polymer surfactant such as polyvinylpyrrolidone may also be added. Examples of inorganic conductive agents include metal ions, conductive carbon, etc. Metal ions can be generated by dissolving a metal salt in water. Examples of the antifoaming agent include silicone resin, polydimethylsiloxane, and silicone oil. Examples of the coupling agent include silane coupling agents having an epoxy group, a vinyl group, or an amino group. Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, oxanilide-based ultraviolet absorbers, hindered amine-based ultraviolet absorbers, and benzoate-based ultraviolet absorbers.

[0052] When the conductive polymer-containing liquid of this embodiment contains other additives, the content ratio thereof is determined appropriately depending on the type of additive, but can be, for example, in the range of 0.001 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the conductive composite.

[0053] <Method of manufacturing conductive polymer-containing liquid> The conductive polymer-containing liquid of the first embodiment can be produced, for example, by the following method. First, a conductive polymer aqueous dispersion in which a π-conjugated conductive polymer and a polyanion are dispersed in water is mixed with a pre-emulsified emulsion resin, an antioxidant, a high-boiling point solvent, and water as needed to obtain a base material. Next, water and a low-boiling point solvent are mixed with the base material as needed, and finally a curing agent is added to obtain the desired conductive polymer-containing liquid.

[0054] A conductive polymer aqueous dispersion is a liquid agent in which a conductive complex is dispersed in water, and can be obtained by a known method. Specifically, for example, it can be obtained by adding a monomer constituting a π-conjugated conductive polymer to an aqueous dispersion of a polyanion and then oxidatively polymerizing the monomer. It can also be purchased as a commercial product.

[0055] <Conductive laminates and conductive films> A second aspect of the present invention is a conductive laminate comprising a substrate and a conductive layer formed on at least a portion of the surface of the substrate, the conductive layer being a cured layer of the conductive polymer-containing liquid of the first aspect. By using a film substrate as the substrate, a conductive film can be obtained.

[0056] [Conductive layer] The conductive layer may be formed over the entire surface of the substrate or over only a portion of the surface. In a conductive film, it is preferable that a conductive layer of substantially uniform thickness is formed over substantially the entire surface of one or the other of the film substrate. When a conductive layer is formed over only a portion of the surface of the substrate, the conductive layer may be, for example, a fine conductive pattern such as a circuit or electrode, or may be simply a roughly divided area where a conductive layer is provided and an area where a conductive layer is not provided exist on the same surface.

[0057] The average thickness of the conductive layer is, for example, preferably 10 nm or more and 100 μm or less, more preferably 20 nm or more and 50 μm or less, and even more preferably 30 nm or more and 30 μm or less. When the average thickness of the conductive layer is equal to or greater than the lower limit, high conductivity can be exhibited, and when the average thickness is equal to or less than the upper limit, the adhesiveness of the conductive layer to the substrate is further improved. The average thickness of the conductive layer is determined by measuring the thickness at 10 randomly selected locations and averaging the measured values.

[0058] [Base material] The substrate may be made of an insulating material or a conductive material. The shape of the substrate is not particularly limited, and examples thereof include a shape mainly having a flat surface, such as a film or a substrate. Examples of insulating materials include glass, synthetic resin, and ceramics. Examples of conductive materials include metals, conductive metal oxides, and carbon.

[0059] (Film substrate) When a film substrate is used as the substrate, the conductive laminate becomes a conductive film. Examples of the film substrate include plastic films made of synthetic resins, such as ethylene-methyl methacrylate copolymer resin, ethylene-vinyl acetate copolymer resin, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacrylate, polycarbonate, polyvinylidene fluoride, polyarylate, styrene-based elastomers, polyester-based elastomers, polyethersulfone, polyetherimide, polyetheretherketone, polyphenylene sulfide, polyimide, cellulose triacetate, and cellulose acetate propionate. From the viewpoint of improving the adhesion between the film substrate and the conductive layer, the synthetic resin for the film substrate is preferably a polyester resin, and among these, polyethylene terephthalate is preferred.

[0060] The synthetic resin for the film substrate may be amorphous or crystalline. The film substrate may be unstretched or stretched. The film substrate may be subjected to a surface treatment such as corona discharge treatment, plasma treatment, or flame treatment in order to further improve the adhesion of the conductive layer.

[0061] The average thickness of the film substrate is preferably 5 μm or more and 500 μm or less, and more preferably 20 μm or more and 200 μm or less. When the average thickness of the film substrate is equal to or more than the lower limit, the film is less likely to break, and when the average thickness is equal to or less than the upper limit, the film can have sufficient flexibility. The average thickness of the film substrate is determined by measuring the thickness at 10 randomly selected locations and averaging the measured values.

[0062] (glass substrate) Examples of the glass substrate include an alkali-free glass substrate, a soda-lime glass substrate, a borosilicate glass substrate, and a quartz glass substrate. If the substrate contains an alkali component, the conductivity of the conductive layer tends to decrease. Therefore, among the glass substrates, an alkali-free glass is preferred. Here, alkali-free glass refers to a glass composition having an alkali component content of 0.1% by mass or less relative to the total mass of the glass composition.

[0063] The average thickness of the glass substrate is preferably 100 μm or more and 3000 μm or less, and more preferably 100 μm or more and 1000 μm or less. When the average thickness of the glass substrate is equal to or more than the lower limit, the glass substrate is less likely to break, and when the average thickness is equal to or less than the upper limit, the conductive laminate can be made thinner. The average thickness of the glass substrate is determined by measuring the thickness at 10 randomly selected locations and averaging the measured values.

[0064] As a measure of good conductivity of the conductive layer of this embodiment, for example, 1×10 5 Ω / □ or more 1×10 8 It is preferable that the surface resistance is Ω / □ or less, and 1×10 5 Ω / □ or more 1×10 7 It is more preferable that the surface resistance is Ω / □ or less.

[0065] <Method for manufacturing conductive laminate and method for manufacturing conductive film> A third aspect of the present invention is a method for producing a conductive laminate, comprising a step of applying the conductive polymer-containing liquid of the first aspect to at least a part of the surface of a substrate. By using a film substrate as the substrate, a conductive film can be produced.

[0066] The explanation of the substrate is the same as that given above, so a duplicate explanation will be omitted here.

[0067] Examples of a method for applying (coating) the conductive polymer-containing liquid to any surface of a substrate include a method using a coater such as a gravure coater, roll coater, curtain flow coater, spin coater, bar coater, reverse coater, kiss coater, fountain coater, rod coater, air doctor coater, knife coater, blade coater, cast coater, or screen coater; a method using a sprayer such as an air spray, airless spray, or rotor dampening; and an immersion method such as dipping.

[0068] The amount of conductive polymer-containing liquid to be applied to the substrate is not particularly limited, but taking into consideration the need for uniform and even application, conductivity, and film strength, it is recommended to apply a solid content of 0.01 g / m 2 More than 10.0g / m 2 The following ranges are preferred:

[0069] The conductive layer can be formed by drying the coating film made of the conductive polymer-containing liquid applied onto the substrate to remove at least a portion of the dispersion medium and then curing the coating film. Methods for drying the coating film include heat drying, vacuum drying, etc. Heat drying can be performed using, for example, hot air heating or infrared heating. When heat drying is applied, the heating temperature is appropriately set depending on the dispersion medium used, but is usually within the range of 50°C to 200°C. Here, the heating temperature is the temperature set in the drying device. A suitable drying time within the above heating temperature range is preferably 0.5 minutes to 30 minutes, more preferably 1 minute to 15 minutes. After drying, UV irradiation may be carried out to cure the binder component contained in the coating film.

[0070] The conductive layer may be formed over the entire surface of the substrate or over only a portion of the surface. In a conductive film, it is preferable that a conductive layer of substantially uniform thickness is formed over substantially the entire surface of one or the other of the film substrate. When a conductive layer is formed over only a portion of the surface of the substrate, the conductive layer may be, for example, a fine conductive pattern such as a circuit or electrode, or may be simply a roughly divided area where a conductive layer is provided and an area where a conductive layer is not provided exist on the same surface.

[0071] The explanation of the average thickness of the conductive layer is the same as that given above, so a duplicate explanation will be omitted here. [Example]

[0072] (Production Example 1) Production of polystyrene sulfonic acid 206 g of sodium styrenesulfonate was dissolved in 1000 ml of ion-exchanged water, and while stirring at 80°C, 1.14 g of an oxidizing agent solution of ammonium persulfate, which had been dissolved in 10 ml of water in advance, was added dropwise over 20 minutes, and the solution was stirred for 12 hours. To the resulting sodium polystyrene sulfonate-containing solution, 1000 ml of sulfuric acid diluted to 10% by mass was added, and approximately 1000 ml of the solvent from the resulting polystyrene sulfonic acid-containing solution was removed by ultrafiltration. Next, 2000 ml of ion-exchanged water was added to the remaining solution, and approximately 2000 ml of the solvent was removed by ultrafiltration, and the polystyrene sulfonic acid was washed with water. This water washing procedure was repeated three times. The water in the resulting solution was removed under reduced pressure to obtain a colorless solid polystyrene sulfonate (PSS). The weight-average molecular weight of this PSS was measured using a high-performance liquid chromatography system equipped with a gel filtration chromatography column and pullulan (manufactured by Showa Denko K.K.) as a standard substance, and was found to be 300,000.

[0073] (Production Example 2) Production of PEDOT-PSS aqueous dispersion A solution prepared by dissolving 14.2 g of 3,4-ethylenedioxythiophene and 44.0 g of polystyrene sulfonic acid obtained in Production Example 1 in 2000 ml of ion-exchanged water was mixed at 20°C. The resulting mixed solution was kept at 20°C and, while stirring, an oxidation catalyst solution of 29.64 g of ammonium persulfate and 8.0 g of ferric sulfate dissolved in 200 ml of ion-exchanged water was slowly added, followed by stirring for 3 hours to allow the reaction to proceed. To the resulting reaction solution, 2000 ml of ion-exchanged water was added, and about 2000 ml of the solvent was removed by ultrafiltration. This procedure was repeated three times. Next, 200 ml of 10% diluted sulfuric acid and 2000 ml of ion-exchanged water were added to the resulting solution, and approximately 2000 ml of the solvent was removed by ultrafiltration. 2000 ml of ion-exchanged water was added to the remaining liquid, and approximately 2000 ml of the solvent was removed by ultrafiltration. This procedure was repeated three times. 2000 ml of ion-exchanged water was added to the resulting solution, and approximately 2000 ml of solvent was removed by ultrafiltration. This procedure was repeated five times to obtain a polystyrene sulfonate-doped poly(3,4-ethylenedioxythiophene) aqueous dispersion (PEDOT-PSS aqueous dispersion) with a solids concentration (non-volatile component concentration) of 1.2% by mass and a PEDOT:PSS ratio of 1:3 by mass.

[0074] (Production Example 3) Production of a Conductive Polymer-Containing Liquid To 40 g of the PEDOT-PSS aqueous dispersion produced in Production Example 2, 20 g of Plascoat Z-690 (manufactured by GOO Chemical Industry Co., Ltd.; a sulfo group-containing polyester having an emulsified polyethylene naphthalate skeleton) was added, and 0.3 g of methyl gallate as an antioxidant, 15 g of propylene glycol as a high-boiling point solvent, and 24.7 g of ion-exchanged water were further mixed, resulting in conductive polymer-containing liquid A.

[0075] [Example 1] 100 g of the conductive polymer-containing liquid A obtained in Production Example 3 was mixed with 900 g of water and 1,000 g of isopropanol, and then 0.5 g of Chemitite DZ-22E (manufactured by Nippon Shokubai Co., Ltd.; emulsion type, solid content 29 to 33 mass %, active ingredient 24 to 26 mass %), which is a curing agent having an aziridinyl group and is represented by the above formula (1), was added to obtain the desired conductive polymer-containing liquid.

[0076] [Example 2] A conductive polymer-containing liquid was obtained in the same manner as in Example 1, except that the amount of Chemitite DZ-22E added was changed to 1.0 g.

[0077] [Example 3] A conductive polymer-containing liquid was obtained in the same manner as in Example 1, except that the amount of Chemitite DZ-22E added was changed to 2.0 g.

[0078] [Example 4] A conductive polymer-containing liquid was obtained in the same manner as in Example 1, except that the amount of Chemitite DZ-22E added was changed to 3.0 g.

[0079] [Comparative Example 1] A conductive polymer-containing liquid was obtained in the same manner as in Example 1, except that Chemitite DZ-22E was not added.

[0080] <Atmospheric exposure assessment> The conductive polymer-containing liquid obtained in each example was applied to a PET film (Lumirror T60, manufactured by Toray Industries, Inc.) using a #4 bar coater, and dried at 120°C for 1 minute to obtain a conductive film with a conductive layer formed on the surface. For each conductive film, the surface resistance (initial surface resistance) R0 was measured within one hour after production, and the surface resistance (surface resistance after atmospheric exposure) R1 was measured after leaving the surface of the conductive layer exposed to air adjusted to a temperature of 25°C and humidity of 50% (hereinafter referred to as atmospheric exposure state) for 7 days (unit: Ω / □: ohms per square). A resistivity meter (Hiresta manufactured by Mitsubishi Chemical Analytech Co., Ltd.) was used for the measurements, and the applied voltage was 10 V. The measurement results are shown in Table 1. In the table, "1.E+07" means "1.0 x 10 7 " and so on.

[0081] The smaller the surface resistance value (unit: Ω / □) in each measurement result, the higher the conductivity. Also, the smaller the rate of change (the ratio of surface resistance values ​​expressed as R1 / R0), the more successfully the decrease in conductivity over time after manufacturing was suppressed. The results in Table 1 show that the conductive films of Examples 1 to 4, compared to Comparative Example 1, showed less decrease in conductivity over time from immediately after production to 7 days. Examples 3 and 4 are reference examples.

[0082] [Table 1]

[0083] <Solvent resistance evaluation> The conductive polymer-containing liquid obtained in each example was applied to a PET film (Lumirror T60, manufactured by Toray Industries, Inc.) using a #4 bar coater, and dried at 120°C for 1 minute to obtain a conductive film with a conductive layer formed on the surface. The surface resistance value (surface resistance value before treatment) R0 of each conductive film was measured within one hour after preparation, and then the film was soaked in various solvents at 10 g / cm 2 The surface resistance value (surface resistance value after treatment) R3 of the area rubbed with a load of 1.0×10 was measured. The measurement results are shown in Tables 2 and 3. In the tables, "1.E+07" means "1.0×10 7 " and so on.

[0084] The smaller the surface resistance value (unit: Ω / □) in each measurement result, the higher the conductivity. Also, the smaller the rate of change (the ratio of surface resistance values ​​expressed as R3 / R0), the higher the solvent resistance of the conductive layer. The results in Tables 2 and 3 show that the conductive films of Examples 1 and 2 have higher solvent resistance than Comparative Example 1. This is thought to be because in the conductive layers of Examples 1 and 2, the curing agent having an aziridinyl group crosslinked other polymers, making the conductive layers stronger.

[0085] [Table 2]

[0086] [Table 3]

Claims

1. The present invention relates to a curing agent containing a conductive composite including a π-conjugated conductive polymer and a polyanion, water, a low-boiling organic solvent having a boiling point of less than 150°C, a high-boiling solvent having a boiling point of 150°C or more, an emulsion resin having a sulfo group in the molecule, an antioxidant, and a curing agent having two or more groups represented by formula (f1) in the molecule, the content of the emulsion resin is 200 parts by mass or more and 3,000 parts by mass or less when the total content of the π-conjugated conductive polymer and the polyanion is 100 parts by mass, The conductive polymer-containing liquid has a content of the curing agent of 2 parts by mass or more and 9 parts by mass or less relative to 100 parts by mass of the emulsion resin. 【Chemistry 1】

2. The conductive polymer-containing liquid according to claim 1 , wherein the curing agent is a compound represented by formula (1): 【Chemistry 2】

3. 2. The conductive polymer-containing liquid according to claim 1, wherein the emulsion resin is a polyester having a sulfo group in the molecule.

4. The conductive polymer-containing liquid according to claim 3 , wherein the polyester has a polyethylene naphthalate skeleton.

5. 2. The conductive polymer-containing liquid according to claim 1, wherein the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene), or the polyanion is polystyrene sulfonic acid.

6. 2. The conductive polymer-containing liquid according to claim 1, wherein the content of the curing agent is 10 parts by mass or more and 300 parts by mass or less when the total content of the π-conjugated conductive polymer and the polyanion is 100 parts by mass.

7. A film substrate and a conductive layer formed on at least a portion of the surface of the film substrate, A conductive film, wherein the conductive layer is a cured product of the conductive polymer-containing liquid according to any one of claims 1 to 6.

8. A method for producing a conductive film, comprising a step of applying the conductive polymer-containing liquid according to any one of claims 1 to 6 to at least a part of a surface of a film substrate.

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