阅读说明：本技术 导电性高分子组合物及导电性高分子溶液的稳定保存方法 (Conductive polymer composition and method for stably storing conductive polymer solution ) 是由 菅原笃 小西淳 于 2020-05-14 设计创作，主要内容包括：本发明涉及不受冬季、暑期等的气温变化影响,长期保存中的分散稳定性高的导电性高分子组合物和导电性高分子溶液的稳定保存方法。一种导电性高分子组合物,其特征在于,至少包含重均分子量在5000以上且100万以下的范围的N-乙烯基羧酸酰胺聚合物、导电性高分子、和溶剂。一种导电性高分子溶液的稳定保存方法,将N-乙烯基羧酸酰胺聚合物的重均分子量在5000以上且100万以下的范围的N-乙烯基羧酸酰胺聚合物添加于导电性高分子溶液。(The present invention relates to a conductive polymer composition having high dispersion stability during long-term storage regardless of changes in temperature in winter, summer, and the like, and a method for stably storing a conductive polymer solution. A conductive polymer composition characterized by comprising at least an N-vinylcarboxylic acid amide polymer having a weight average molecular weight in the range of 5000 to 100 ten thousand, a conductive polymer, and a solvent. A method for stably storing a conductive polymer solution, wherein an N-vinylcarboxylic acid amide polymer having a weight average molecular weight of 5000 to 100 ten thousand of that of the N-vinylcarboxylic acid amide polymer is added to the conductive polymer solution.)

1. A conductive polymer composition characterized by comprising at least an N-vinylcarboxylic acid amide polymer having a weight average molecular weight in the range of 5000 to 100 ten thousand, a conductive polymer, and a solvent.

2. The conductive polymer composition according to claim 1, wherein the solid content of the N-vinylcarboxylic acid amide polymer is 10 to 200 parts by mass, based on 100 parts by mass of the solid content of the conductive polymer.

3. The conductive polymer composition according to claim 1 or 2, wherein a solid content concentration of the N-vinylcarboxylic acid amide polymer in the conductive polymer composition is 0.3 mass% or more and 10 mass% or less.

4. The electroconductive polymer composition according to any one of claims 1 to 3, wherein the N-vinylcarboxylic acid amide polymer is an N-vinylacetamide polymer.

5. The conductive polymer composition according to any one of claims 1 to 4, wherein the conductive polymer is poly (3, 4-ethylenedioxythiophene) doped with poly (4-styrenesulfonic acid), and hereinafter, is represented by PEDOT-PSS.

6. The electroconductive polymer composition according to any one of claims 1 to 5, wherein the solvent is water.

7. The conductive polymer composition according to any one of claims 1 to 6, wherein the viscosity of the conductive polymer composition at 20 ℃ is 10 mPas or more and 400 mPas or less.

8. The conductive polymer composition according to any one of claims 1 to 7, wherein a sulfur concentration in the solid content of the N-vinylcarboxylic acid amide polymer is 3000 mass ppm or less.

9. The conductive polymer composition according to any one of claims 1 to 8, wherein the N-vinylcarboxylic acid amide polymer is produced by polymerizing N-vinylcarboxylic acid amide in the presence of a chain transfer agent containing no sulfur atom or without using a chain transfer agent.

10. A method for stably storing a conductive polymer solution, wherein an N-vinylcarboxylic acid amide polymer having a weight average molecular weight of 5000 to 100 ten thousand of that of the N-vinylcarboxylic acid amide polymer is added to the conductive polymer solution.

11. The method for stably storing a conductive polymer solution according to claim 10, wherein the conductive polymer solution contains at least PEDOT-PSS and water.

12. The method for stably storing a conductive polymer solution according to claim 10 or 11, wherein the N-vinylcarboxylic acid amide polymer is an N-vinylacetamide polymer.

13. The method for stably storing a conductive polymer solution according to any one of claims 10 to 12, wherein the N-vinylcarboxylic acid amide polymer is produced by polymerizing N-vinylcarboxylic acid amide in the presence of a chain transfer agent containing no sulfur atom or without using a chain transfer agent.

14. The method for stably storing a conductive polymer solution according to any one of claims 10 to 13, wherein a sulfur concentration in a solid content of the N-vinylcarboxylic acid amide polymer is 3000 ppm by mass or less.

Technical Field

The present invention relates to a conductive polymer composition having high storage stability, and more particularly, to a conductive polymer composition having high dispersion stability during long-term storage without being affected by changes in temperature such as winter and summer seasons, and a method for stably storing a conductive polymer solution.

Background

Conductive polymers are widely used for electrolytes of solid electrolytic capacitors, antistatic materials such as optical films, organic ELs, hole injection layers of solar cells, transparent electrodes, actuators, sensors, thermoelectric conversion elements, and the like.

As such a conductive polymer, the present applicant has proposed a conductive polymer composite comprising a self-doping type conductive polymer having a bronsted acid group in the molecule and an N-vinylcarboxylic acid amide-based polymer in patent document 1 listed below, and has proposed an electrochromic device in which the self-doping type conductive polymer and the N-vinylcarboxylic acid amide-based polymer are interposed as an electrolyte between a pair of electrodes at least one of which is transparent.

The present applicant has proposed, in patent document 2, an electrically conductive composition containing an aqueous solvent-soluble electrically conductive polymer having a pi-electron conjugated system and exhibiting electrical conductivity by an electron conductivity mechanism, and an aqueous solvent-soluble resin. In patent document 2, a material containing poly (5-sulfoisothianaphthene-1, 3-diyl) as an aqueous solvent-soluble conductive polymer and polyvinyl acetamide as an aqueous solvent-soluble resin was evaluated as an example.

Among the conductive polymers, poly (3, 4-ethylenedioxythiophene) (hereinafter also referred to as PEDOT-PSS) doped with poly (4-styrenesulfonic acid) is one of the most commonly used conductive polymers because it has good conductivity and high light transmittance when used as a thin film.

Patent document 3 below discloses a conductive composition comprising PEDOT-PSS, which is a conductive polymer, and poly-N-vinylacetamide (PNVA). Patent document 3 discloses PEDOT-PSS prepared by adding a sulfuric acid-based oxidizing agent, 3, 4-Ethylenedioxythiophene (EDOT) as a polymerizable monomer, and polystyrene sulfonic acid as a dopant to a PNVA aqueous solution to perform a polymerization reaction of EDOT. PNVA is added to improve the adhesion between PEDOT/PSS particles and the adhesion to a substrate.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 10-239715

Patent document 2: japanese patent laid-open publication No. 2006-77229

Patent document 3: japanese laid-open patent publication No. 2012-153867

Non-patent document

Non-patent document 1: "PEDOT/PSS conductive particle characteristics におよぼす additive (effect of additive on conductive characteristics of PEDOT/PSS)" avionics report, No.35, p.1-9, No.3, No. 2013, month 3

Disclosure of Invention

Problems to be solved by the invention

The conductive polymer exists in a dispersed state in the solvent, but the retention of the dispersed state is not permanent. For example, PEDOT-PSS is dispersed in hydrophilic PSS as a hydrophobic polymer (non-patent document 1). However, most PEDOT-PSS products are stored at 2-8 ℃ as specified by manufacturers and stores. In addition, the shelf life (shelf life) under such conditions is often 12 months after production, and a problem is that a change in performance is likely to occur depending on the storage conditions and the storage period.

Specifically, it is known that the PSS cannot maintain the initial dispersed state for a long period of time because the PSS starts to form a cubic structure when intermolecular forces between PSS act.

It is found that the initial dispersed state is largely collapsed particularly when the polymer is cooled to be frozen and thawed during storage in a cold region or when the molecular motion is activated by heating or the like.

In addition, in the process of the above dispersion disintegration or the formation of the tertiary structure by PSS, there is a high possibility that the PSS as an insulating layer becomes the outermost layer by confining PEDOT to the inside or the like, and there is a fear from the viewpoint of maintaining the conductivity.

In addition, in patent document 3, since an oxidizing agent containing a sulfur component such as a sulfate or persulfate is used in the presence of PNVA in the polymerization of EDOT, a large amount of sulfur is contained in the composition, and PNVA used in the polymerization has a high viscosity and a high molecular weight. Further, in patent document 3, GE191-000, which is a product of the present applicant, is used as PNVA, and a 1 mass% aqueous solution thereof has a viscosity as high as 500mPa · s, and a weight average molecular weight of 400 ten thousand, and is derived from a chain transfer agent, and PNVA contains an undesirable sulfur component in a semiconductor. Therefore, the conductive composition described in patent document 3 using such PNVA has a problem that it is difficult to use the composition in a semiconductor and the composition has a high viscosity and is difficult to use as a dispersant.

Means for solving the problems

Under such circumstances, the present inventors have conducted intensive studies and as a result, found that the molecular weight of the N-vinylcarboxylic acid amide polymer greatly affects the long-term storage stability of the electroconductive polymer composition. Further, the present inventors have found that the storage stability is remarkably improved by adding a specific N-vinylcarboxylic acid amide polymer to a conductive polymer composition, and have completed the present invention.

That is, the present invention is configured as follows.

[1] A conductive polymer composition characterized by comprising at least an N-vinylcarboxylic acid amide polymer having a weight average molecular weight in the range of 5000 to 100 ten thousand, a conductive polymer, and a solvent.

[2] The conductive polymer composition according to [1], wherein the solid content of the N-vinylcarboxylic acid amide polymer is 10 to 200 parts by mass, based on 100 parts by mass of the solid content of the conductive polymer.

[3] The conductive polymer composition according to [1] or [2], wherein a solid content concentration of the N-vinylcarboxylic acid amide polymer in the conductive polymer composition is 0.3 mass% or more and 10 mass% or less.

[4] The electroconductive polymer composition according to any one of [1] to [3], wherein the N-vinylcarboxylic acid amide polymer is an N-vinylacetamide polymer.

[5] The conductive polymer composition according to [1] to [4], characterized in that the conductive polymer is poly (3, 4-ethylenedioxythiophene) (hereinafter, PEDOT-PSS) doped with poly (4-styrenesulfonic acid).

[6] The conductive polymer composition according to any one of [1] to [5], wherein the solvent is water.

[7] The conductive polymer composition according to [1] to [6], characterized in that the viscosity of the conductive polymer composition at 20 ℃ is 10 mPas to 400 mPas.

[8] The conductive polymer composition according to any one of [1] to [7], wherein the sulfur concentration in the solid content of the N-vinylcarboxylic acid amide polymer is 3000 ppm by mass or less.

[9] The conductive polymer composition according to any one of [1] to [8], wherein the N-vinylcarboxylic acid amide polymer is produced by polymerizing N-vinylcarboxylic acid amide in the presence of a chain transfer agent containing no sulfur atom or without using a chain transfer agent.

[10] A method for stably storing a conductive polymer solution, wherein an N-vinylcarboxylic acid amide polymer having a weight average molecular weight of 5000 to 100 ten thousand of that of the N-vinylcarboxylic acid amide polymer is added to the conductive polymer solution.

[11] The method for stably storing a conductive polymer solution according to [10], wherein the conductive polymer solution contains at least PEDOT-PSS and water.

[12] The method for stably storing a conductive polymer solution according to [10] or [11], wherein the N-vinylcarboxylic acid amide polymer is an N-vinylacetamide polymer.

[13] The method for stably storing a conductive polymer solution according to any one of [10] to [12], wherein the N-vinylcarboxylic acid amide polymer is produced by polymerizing N-vinylcarboxylic acid amide in the presence of a chain transfer agent containing no sulfur atom or without using a chain transfer agent.

[14] The method for stably storing a conductive polymer solution according to any one of [10] to [13], wherein the sulfur concentration in the solid content of the N-vinylcarboxylic acid amide polymer is 3000 ppm by mass or less.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, storage stability is significantly improved by adding a specific N-vinylcarboxylic acid amide polymer to a conductive polymer solution.

The present inventors have examined that the addition of an N-vinylcarboxylic acid amide polymer used in the present invention to PEDOT-PSS, for example, can reduce the intermolecular force between PEDOT and PSS or the intermolecular force between a complex of PSS and PEDOT, thereby preventing triple-order structuring of PSS alone. It is noted that PEDOT-PSS is known to form high order structures, which contribute to the cohesiveness.

Furthermore, the dispersibility of PEDOT in water can be ensured or improved by the amphiphilicity of the N-vinylcarboxylic acid amide polymer, and further, the long-term conductive performance can be maintained. In addition, although the PEDOT-PSS solution is strongly acidic for stability, PNVA, which has excellent acid resistance, does not change even in such a strongly acidic solution, and is further excellent in heat resistance, and therefore, the effect can be continuously exhibited even when heated during the molding of the conductive polymer film.

Since the sulfur atom has a high possibility of affecting the movement of electrons, in the present invention, if an N-vinylcarboxylic acid amide polymer having a sulfur content reduced to a predetermined range is used, the high conductivity can be maintained more stably.

Actually, other materials may be discolored in the acceleration test in the N-vinylcarboxylic acid amide polymer polymerized using a chain transfer agent containing an SH group or the N-vinylcarboxylic acid amide polymer containing a large amount of sulfur atoms.

The N-vinylcarboxylic acid amide polymer of the present invention can improve the affinity for a glass substrate, a metal, or the like when forming a conductive polymer film while maintaining sufficient wettability.

Further, the N-vinylcarboxylic acid amide polymer itself has excellent transparency, and therefore, can be applied to applications requiring transparency, and further, an antistatic effect can be expected.

Drawings

Fig. 1 shows the particle size distribution of the conductive polymer composition after the freezing and heating tests evaluated in example 1.

Fig. 2 shows the particle size distribution of the conductive polymer composition after the freezing and heating tests evaluated in comparative example 1.

Detailed Description

The present invention will be described in detail below. The compositions of the present invention are of course not limited to them.

The conductive polymer composition of the present invention contains at least an N-vinylcarboxylic acid amide polymer, a conductive polymer, and a solvent.

< N-vinylcarboxylic acid amide Polymer >

The N-vinylcarboxylic acid amide polymer of the present invention is obtained by polymerizing an N-vinylcarboxylic acid amide monomer represented by the formula (1).

(in the general formula (1), R¹Is any 1 selected from hydrogen atoms and alkyl groups with 1-6 carbon atoms. R²Represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. R¹Can be reacted with NR²Forming a ring structure. )

Specific examples of the N-vinylcarboxylic acid amide include N-vinylformamide, N-vinylacetamide, N-vinylpropionamide, N-vinylbenzamide, N-vinyl-N-methylformamide, N-vinyl-N-ethylformamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, and N-vinylpyrrolidone. Among these, N-vinylacetamide is particularly preferable in view of the balance between hydrophilicity and hydrophobicity of the polymer. The N-vinylcarboxylic acid amides may be used singly or in combination of two or more.

The N-vinylcarboxylic acid amide polymer is preferably a homopolymer of only N-vinylcarboxylic acid amide. On the other hand, the monomer copolymerizable with the N-vinylcarboxylic acid amide (hereinafter, sometimes referred to as "other monomer") may be contained in addition to the N-vinylcarboxylic acid amide. The other monomer is at least 1 monomer selected from unsaturated carboxylic acid monomers, salts of unsaturated carboxylic acid monomers, unsaturated carboxylic acid ester monomers, vinyl ester monomers and unsaturated nitrile monomers. Among them, (meth) acrylic acid and salts thereof are more preferable, and sodium acrylate is still more preferable. In the present specification, "(meth) acrylic" refers to acrylic acid and methacrylic acid.

N-vinyl carboxylic acid amide polymer if the structural unit derived from N-vinyl carboxylic acid amide is 1.00, the ratio of the number of moles of the other structural units derived from N-vinyl acetamide is preferably less than 0.250, so that water solubility can be obtained. The ratio of the number of moles of the structural unit in the N-vinylacetamide copolymer is more preferably 0.150 or less, and still more preferably 0.

In polymerizing the N-vinylcarboxylic acid amide monomer, a polymerization initiator may be used. As the polymerization initiator, those generally used for radical polymerization of vinyl compounds can be used without limitation. Examples thereof include redox polymerization initiators, azo compound polymerization initiators, and peroxide polymerization initiators.

These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The redox polymerization initiator is not particularly limited as long as it is a method of adding a peroxide and a reducing agent, but is preferably a substance containing no sulfur atom because of coloring or the like. The peroxide is a compound having a bond of oxygen atoms, and is preferably a derivative of hydrogen peroxide such as sodium peroxide/barium peroxide. The reducing agent is preferably a reducing agent containing a 2-valent iron ion, an amine, a hydrogen peroxide-ferrous chloride-based reducing agent, or the like, and more preferably a substance containing no sulfur atom.

Examples of the peroxide-based polymerization initiator include organic peroxides such as sodium, potassium and ammonium persulfates, benzoyl peroxide, lauroyl peroxide, hexanoyl peroxide, t-butyl peroctoate (t- ブチルパーオクトエイト), and diacetyl peroxide.

Examples of the azo compound-based polymerization initiator include 2,2 ' -azobis (2-methylbutyronitrile), 2 ' -azobis (2, 4-dimethylvaleronitrile), dimethyl 2,2 ' -azobis (isobutyrate), dimethyl 2,2 ' -azobis (2-methylbutyrate) and dimethyl 2,2 ' -azobis (2, 4-dimethylpentanoate), azo compounds such as 2,2 '-azobis (2-amidinopropane) dihydrochloride, 2' -azobis [ N- (2-carboxyethyl) -2-methylpropionamidine ] N hydrate, 2 '-azobis [2- [ N- (2-carboxyethyl) amidino ] propane } N hydrate, and dimethyl 2, 2' -azobis (2-methylpropionate).

Among the above polymerization initiators, a water-soluble polymerization initiator is preferable because water is preferably used as the solvent. Furthermore, in consideration of the influence of the residue on the polymer, it is most preferable to use 2, 2' -azobis [ N- (carboxyethyl) -2-methylpropionamidine ] tetrahydrate (trade name: Fuji フィルム and azo compound polymerization initiator VA-057 made by Kyowa Kayaku Co., Ltd.) containing no halogen.

The polymerization initiator is preferably used by dissolving in water such as ion-exchanged water.

These radical polymerization initiators can be used in combination, and polymerization can be performed even when a redox polymerization initiator and a water-soluble azo compound polymerization initiator are used in combination. As the redox polymerization initiator, a hydrogen peroxide derivative and an amine are preferably used, and as the water-soluble azo compound polymerization initiator, 2' -azobis (2-amidinopropane) dihydrochloride is more preferably used.

The amount of the radical polymerization initiator used is preferably 0.05 to 8.0 parts by mass, more preferably 0.5 to 6.0 parts by mass, and still more preferably 1.0 to 4.0 parts by mass, in the case of the azo compound-based polymerization initiator, relative to 100 parts by mass of the total amount of all monomers. In the case of the redox polymerization initiator, it is preferably 0.001 part by mass or more and 0.03 part by mass or less, more preferably 0.003 part by mass or more and 0.01 part by mass or less, and still more preferably 0.004 part by mass or more and 0.009 part by mass or less, relative to 100 parts by mass of the total amount of all monomers. If the amount of the radical polymerization initiator used is within the above range, both the polymerization rate and the molecular weight of the copolymer are easily suitable.

In the polymerization of the N-vinylcarboxylic acid amide monomer, the molecular weight can be adjusted by using a chain transfer agent. The chain transfer agent is not particularly limited as long as it is soluble in the monomer or solvent, and examples thereof include alkyl mercaptans such as dodecyl mercaptan and heptyl mercaptan, water-soluble mercaptans having a polar group such as 3-mercaptopropionic acid (BMPA), and oily radical inhibitors such as α -styrene dimer. In addition, secondary alcohols such as isopropyl alcohol; phosphorous acid, hypophosphorous acid and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), carbon tetrachloride, and the like.

When polymerizing an N-vinylcarboxylic acid amide polymer having a low molecular weight and a low viscosity, it is preferable not to use a chain transfer agent, but when used, it is preferable to use a substance that does not contain a sulfur atom such as thiol. It is considered that the sulfur atom in the chain transfer agent affects the electron transfer of the conductive polymer. In order to reduce the sulfur concentration, it is preferable not to use sulfurous acid, sulfite, or the like, which is used as a polymerization initiator or a chain transfer agent and has high water solubility. If sulfur atoms are contained, they may cause coloring or the like, and may impair dispersibility for long-term storage.

On the other hand, even when a chain transfer agent or a polymerization initiator containing a sulfur component is used, it can be used in consideration of the concentration of sulfur atoms as described later. In this case, thiol compounds such as 2-hydroxyethylthiol, 3-mercaptopropionic acid, dodecylthiol, thioacetic acid, and 3-mercapto-1, 2-propanediol are preferable.

The concentration of the sulfur atom in the N-vinylcarboxylic acid amide polymer is preferably 0 to 6000 mass ppm, more preferably 0 to 3000 mass ppm, and still more preferably 0 to 500 mass ppm, based on the total amount of all monomers.

Since the aqueous solution containing the N-vinylcarboxylic acid amide polymer has a high refractive index and is stable under redox conditions, it is less likely to undergo changes due to changes in heating and changes over time even when mixed with a conductive polymer, and as a result, transparency can be maintained.

In order not to thicken the conductive polymer composition, the weight average molecular weight of the N-vinylcarboxylic acid amide polymer is 5000 to 100 ten thousand, preferably 1 to 50 ten thousand, more preferably 2 to 30 ten thousand, and still more preferably 3 to 10 ten thousand.

The viscosity of a 5 mass% aqueous solution of the N-vinylcarboxylic acid amide polymer at 20 ℃ is 10 mPas or more and 5000 mPas or less, more preferably 20 mPas or more and 2000 mPas or less, and still more preferably 30 mPas or more and 100 mPas or less. When the viscosity is 10 mPas or more, a molecular weight necessary for dispersibility can be obtained, which is preferable. It is preferable that the viscosity is 2000 mPas or less since the viscosity is not increased, and the dispersion stability can be imparted without changing the liquid properties of PEDOT-PSS.

When the N-vinylcarboxylic acid amide polymer contains water as a solvent, the pH of the conductive polymer is usually in the range of 4 to 10.

When the N-vinylcarboxylic acid amide contains a solvent, the solid content concentration of the N-vinylcarboxylic acid amide is preferably 1 mass% or more and 40 mass% or less, more preferably 2 mass% or more and 20 mass% or less, and still more preferably 3 mass% or more and 12 mass% or less. When the content of the N-vinylcarboxylic acid amide polymer is 1 mass% or more and 40 mass%, handling of the conductive polymer composition becomes easy, which is preferable.

< conductive Polymer >

As the conductive polymer, a combination of an anion-doped conductive polymer and a dopant is preferable.

The anion-doped conductive polymer is preferably selected from the group consisting of: polyacetylene, aromatic conjugated system: poly (p-phenylene), mixed conjugated poly (p-1, 4-phenylenevinylene), heterocyclic conjugated polypyrrole, polythiophene, heteroatom-containing conjugated: polyaniline, multi-chain conjugated system: polyacene (a hypothetical molecule), and the like. Among them, poly (3, 4-ethylenedioxythiophene) (hereinafter also referred to as PEDOT) is particularly preferable.

The dopant may be one having an electron donating and receiving function, but preferably in order to maintain the conductivity of the coating film, a dopant having a sulfonic acid group is suitable, and preferably at least 1 selected from the group consisting of polystyrenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, 1, 5-anthraquinone disulfonic acid, 2, 6-anthraquinone disulfonic acid, anthraquinone sulfonic acid, 4-hydroxybenzenesulfonic acid, methanesulfonic acid, nitrobenzenesulfonic acid, and the like. Among them, poly (4-styrenesulfonic acid) (hereinafter, also referred to as PSS) is particularly preferable.

Among these, the combination of poly (3, 4-ethylenedioxythiophene) (hereinafter also referred to as PEDOT-PSS) doped with poly (4-styrenesulfonic acid) is most preferable.

The relationship between the conductive polymer and the N-vinylcarboxylic acid amide polymer is such that the solid content of the N-vinylcarboxylic acid amide polymer is preferably 10 parts by mass or more and 200 parts by mass or less, more preferably 20 parts by mass or more and 140 parts by mass or less, and still more preferably 30 parts by mass or more and 70 parts by mass or less, when the solid content of the conductive polymer is 100 parts by mass.

When the amount is contained in such a ratio, the change with time of the conductive polymer can be sufficiently suppressed, which is preferable.

< solvent >

The solvent used in the conductive polymer composition of the present invention is preferably a polar solvent such as water or alcohol, and particularly preferably water. Among them, water is particularly preferable from the viewpoint of dispersibility of the conductive polymer and the N-vinylcarboxylic acid amide polymer.

< composition >

The composition of the conductive polymer composition is preferably such that the solid content composed of the N-vinylcarboxylic acid amide polymer and the conductive polymer is in the range of preferably 0.1 to 30.0% by mass, more preferably 0.5 to 20.0% by mass, and still more preferably 1.0 to 5.0% by mass, based on 100% by mass of the total composition.

The amount of the N-vinylcarboxylic acid amide polymer in the solid content is preferably 10 to 80% by mass, more preferably 20 to 60% by mass, and still more preferably 30 to 40% by mass in the solid content.

The solid content concentration of the N-vinylcarboxylic acid amide polymer in the electroconductive polymer composition is preferably 0.3% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, and further preferably 0.7% by mass or more and 3% by mass or less.

When the amount is contained in such a ratio, the change with time of the conductive polymer can be sufficiently suppressed, and the viscosity of the conductive polymer composition does not increase, which is preferable.

The N-vinylcarboxylic acid amide polymer alone has an effect of stabilizing dispersion of the conductive polymer, and in this case, it can be used in the form of a solution or a dispersion obtained by dissolving it in a solvent.

The viscosity of the conductive polymer composition is preferably 10 to 400mPa · s, more preferably 20 to 300mPa · s, and still more preferably 30 to 200mPa · s. When the viscosity is 10 mPas or more, a polymer having a molecular weight necessary for dispersibility is contained. When the viscosity is 400 mPas or less, the viscosity is preferably not increased, and thus dispersion stability can be imparted without changing the liquid properties of PEDOT-PSS.

The conductive polymer to be added is not particularly limited, and the above-mentioned substances are exemplified, and PEDOT and PSS are preferable.

According to the present invention, a method for stably storing a conductive polymer solution can also be provided by adding the N-vinylcarboxylic acid amide polymer or the conductive polymer dispersion stabilizer containing the same to the conductive polymer solution.

Examples

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

< concentration of solid component >

The solid content concentration was calculated as follows.

About 3.0g of a sample (N-vinylcarboxylic acid amide polymer, or electroconductive polymer composition) was placed on an aluminum cup, spread smoothly and uniformly at the bottom of the aluminum cup with a spatula, dried by heating at 140 ℃ for 90 minutes using a thermobalance (PM 460, manufactured by メトラー & トレド Co., Ltd.), and measured for the mass after cooling, and the solid content concentration using the following formula.

Solid content concentration (mass%) < 100 × (M3-M1) ÷ (M2-M1)

M1: aluminum cup quality (g)

M2: sample mass before drying + aluminum cup mass (g)

M3: sample quality after drying + aluminum cup quality (g)

< viscosity >

When the viscosity of the aqueous solution of the N-vinylcarboxylic acid amide polymer was measured, the N-vinylcarboxylic acid amide polymer was charged into a 300ml beaker and diluted with ion-exchanged water so that the solid content concentration became 5 mass%. In addition, when the viscosity of the conductive polymer composition is measured, the measurement is performed without dilution. The mixture was left to stand in a thermostatic bath at 20 ℃ for 12 hours or more, and the bubbles in the mixture were completely eliminated. Then, the temperature was adjusted to 20 ℃ in a constant temperature water bath, a beaker was placed, the temperature of the test piece was confirmed to be 20. + -. 0.5 ℃ by a thermometer, and the viscosity was measured under the following conditions using a type B viscometer as shown in JIS K-7117-1-1999. The viscosity after 10 minutes was recorded from the viscometer setting.

Viscometer: DVE (Brookfield) viscometer type HA

A rotor: no.6 rotor

Rotating speed: 50rpm

Temperature: 20 deg.C

< particle diameter >

Using laser lightThe median particle diameter based on the volume distribution (hereinafter, also referred to as "d" in some cases) was measured using a diffraction/scattering type particle diameter distribution measuring apparatus, particle mini LA-350 manufactured by horiba, Ltd₅₀) Volume average diameter on volume distribution basis.

< determination of the Absolute molecular weight of a Standard N-vinylacetamide Polymer for the preparation of a GPC calibration Curve >

The N-vinylacetamide homopolymers of the respective molecular weight bands were dissolved in the eluent, and the mixture was allowed to stand for 20 hours. The solid content concentration in the solution was 0.05 mass%.

This was filtered through a 0.45 μm membrane filter, and the absolute molecular weight at the peak position was measured from the filtrate by using GPC-MALS (Multi Angle light Scattering Detector).

GPC: shodex (registered trademark) SYSTEM21 available from Showa Denko K.K

Column: shodex (registered trademark) LB-80 available from Showa Denko K.K.

Column temperature: 40 deg.C

Eluent: 0.1mol/L NaH₂PO₄+0.1mol/L Na₂HPO₄

Flow rate: 0.64mL/min

Sample introduction amount: 100 μ L

MALS detector: model ワイアットテクノロジーコーポレーション DAWN (registered trademark) DSP

Laser wavelength: 633nm

The multi-angle fitting method comprises the following steps: berry method

< weight average molecular weight >

The N-vinylacetamide polymer was diluted with distilled water so that the solid content concentration became 0.1 mass%, and the weight average molecular weight Mw was measured by GPC (gel permeation chromatography) under the following conditions.

In the present measurement, a calibration curve prepared from the results of measuring the absolute molecular weight of the N-vinylacetamide polymer in each molecular weight band using a multiangle light scattering detector was used as the weight average molecular weight.

Detector (RI): SHODEX (registered trademark) RI-201H manufactured by SHOWA DENKO K.K

A pump: LC-20AD manufactured by Shimadzu corporation

Column oven: SHODEX (registered trademark) AO-30C manufactured by SHOWA DENKO K.K

An analysis device: SIC 480II Deta Station manufactured by システムインスツルメンツ K.K

Column: SHODEX (registered trademark) SB806(2 root) manufactured by SHOWA AND ELECTRICAL CO

Eluent: distilled water/2-propanol 8/2 (mass ratio)

Flow rate: 0.7ml/min

< suction filtration test >

10ml of the conductive polymer composition was filtered under reduced pressure using a membrane filter having a pore size of 0.45 μm and a funnel, and the number of aggregates obtained on the filter paper was visually measured.

< color change >

The change in color of the conductive polymer composition before and after the storage stability test was visually confirmed.

Production example 1

A 5-neck 1L separable flask was equipped with a nitrogen inlet, a stirrer, 2 solvent dropping devices, and a thermometer, and 250g of ion-exchanged water adjusted to pH 7.0 with triethanolamine was put into the separable flask. The solution was stirred while being replaced with nitrogen, and stirred at 99 ℃ for 120 minutes. 107g of N-vinylacetamide (manufactured by Showa Denko K.K.) and 140g of ion-exchanged water adjusted to pH 7.0 with triethanolamine were added to a solvent dropping device and dissolved. In another solvent dropping apparatus, 3.2g of 2, 2' -azobis [ N- (carboxyethyl) -2-methylpropionamidine ] tetrahydrate (hereinafter, VA-057) (manufactured by fuji フィルム and pure chinese japan) as a polymerization initiator was dispersed in 40g of ion-exchanged water adjusted to pH 7.0 with triethanolamine. The separable flask was maintained at 99 ℃ and the above-mentioned solution and dispersion were dropped into the separable flask from 2 solvent dropping apparatuses by using a pump over 2 hours, respectively. After the completion of the addition, the mixture was held for 15 minutes, and then 35g of ion-exchanged water adjusted to pH 7.0 with triethanolamine was dispersed in VA-0570.5 g, and the mixture was added dropwise from the solvent dropping apparatus over 5 minutes. The amount of the polymerization initiator was 3.4% by mass based on the monomer. After 45 minutes, 488g of ion-exchanged water adjusted to pH 7.0 with triethanolamine was added and cooled, and the mixture was held at 50 ℃ for 1 hour, and then a sample was taken to confirm that the residual N-vinyl acetamide monomer concentration was 1,000 mass ppm or less, and the reaction was completed. The weight average molecular weight of the N-vinylcarboxylic acid amide polymer was 80,000, and the viscosity of an aqueous solution having a solid content concentration of 5% by mass was 80 mPaS.

Production example 2

The procedure of preparation example 1 was repeated except that 107g of N-vinylacetamide (available from Showa Denko K.K.) and 140g of ion-exchanged water adjusted to pH 7.0 with triethanolamine were added, and 1.6g of 3-mercapto-1, 2-propanediol (available from Asahi chemical industries Co., Ltd.) was added as a chain transfer agent. The weight-average molecular weight of the N-vinylcarboxylic acid amide polymer was 59,000, and the viscosity of an aqueous solution having a solid content concentration of 5% by mass was 78 mPaS. The sulfur concentration in the solid content of the N-vinylcarboxylic acid amide polymer was 4500 mass ppm.

[ example 1]

In a 50ml beaker, 2.0g of the aqueous solution of N-vinylacetamide polymer produced in production example 1 was added to 20g of a solution obtained by diluting 4.0 mass% dispersion of PEDOT-PSS with ion-exchanged water by 2 times by mass, and stirred with a magnetic stirrer (400rpm) for 5 minutes to obtain an electroconductive polymer composition.

[ example 2]

The procedure of example 1 was repeated except that the sulfur-containing N-vinylacetamide polymer produced in production example 2 was used as the N-vinylacetamide polymer.

Comparative example 1

The procedure of example 1 was repeated except that 2.0g of water was added instead of the aqueous solution of N-vinylacetamide polymer. The viscosity of water was 20.1mPa · S.

Comparative example 2

The procedure of example 1 was repeated except for using 11g of an N-vinylpyrrolidone polymer (weight-average molecular weight: 40000, viscosity of an aqueous solution having a solid content of 5% by mass: 56.6 mPaS) dissolved in 99g of ion-exchanged water in place of the aqueous solution of the N-vinylacetamide polymer.

Comparative example 3

The procedure of example 1 was repeated except that 11g of powdery N-vinylacetamide polymer (GE 191-000, available from Showa Denko K.K.) was dissolved in 99g of ion-exchanged water as the N-vinylacetamide polymer.

[ example 3]

In a 50ml beaker, 2.0g of the aqueous solution of N-vinylacetamide polymer produced in production example 1 was added to 25g of a solution obtained by diluting 4.0 mass% dispersion of PEDOT-PSS with ion-exchanged water by 2 times, and stirred with a magnetic stirrer (400rpm) for 5 minutes to obtain an electroconductive polymer composition.

[ example 4]

In a 50ml beaker, 1.0g of the aqueous solution of N-vinylacetamide polymer produced in production example 1 was added to 25g of a solution obtained by diluting 4.0 mass% dispersion of PEDOT-PSS with ion-exchanged water by 2 times by mass, and stirred with a magnetic stirrer (400rpm) for 5 minutes to obtain an electroconductive polymer composition.

Comparative example 4

The procedure of example 3 was repeated except that 1.0g of water was added instead of the aqueous solution of N-vinylacetamide polymer.

[ example 5]

In a 50ml beaker, 25g of PEDOT-PSS4.0 mass% dispersion and 1.0g of the aqueous solution of N-vinylacetamide polymer produced in production example 1 were added, and stirred with a magnetic stirrer (400rpm) for 5 minutes to obtain a conductive polymer composition.

Comparative example 5

The procedure of example 5 was repeated except that 1.0g of water was added instead of the aqueous solution of N-vinylacetamide polymer.

The reagents used were as follows.

PEDOT-PSS: シグマアルドリッチジャパン contract Co., Ltd., 3.0-4.0% aqueous solution, high conductivity grade

N-vinyl pyrrolidone polymer: k30 (weight average molecular weight 40000), manufactured by Tokyo Kabushiki Kaisha

N-vinylacetamide polymer (powder): GE191-000, a product of Showa Denko K.K

< evaluation of storage stability >

Storage stability was evaluated for examples 1 and 2 and comparative examples 1 and 2. The N-vinylacetamide of comparative example 3 was not suitable because of its high viscosity, and was not evaluated.

10g of the prepared conductive polymer composition was put into a 20ml glass test tube with a cap and sealed, to prepare a sample treated under the following treatment conditions.

i) Freezing at-15 deg.C for 6Hr

The sample was frozen by keeping the environment at-15 ℃ for 6 hours in a freezer (Japanese フリーザー (strain) KD-3142) and then the sample temperature was adjusted to 30 ℃ over 2 hours.

ii) heating at 80 ℃ for 48Hr

For the other samples, an environment of 80 ℃ was maintained for 48 hours by using an autoclave (ヤマト science, strain DN-41), and then the temperature of the sample was made 30 ℃ over 2 hours.

iii) heating at 97 ℃ X72 Hr

Further, for other samples, an environment of 97 ℃ was maintained for 72 hours by using an autoclave (ヤマト science, strain, DN-41), and then the temperature of the sample was made 30 ℃ over 2 hours.

Heating and freezing were performed as an accelerated test.

The respective samples were subjected to particle size measurement, suction filtration test, and visual observation to confirm discoloration.

The number of aggregates was 0, 1 to 3 were Δ,4 or more were x, no discoloration was a circle, slight discoloration was a triangle, significant discoloration was a x, 2 were all determined as circle, circle Δ and Δ were determined as Δ, and the other were determined as x.

With respect to examples 3 to 5 and comparative examples 4 and 5, a storage stability test was conducted for a longer period of time than in examples 1 and 2 and comparative examples 1 and 2, and evaluation was conducted by viscosity change and particle size measurement.

10g of the conductive polymer composition prepared in examples 3 to 5 and comparative examples 4 and 5 was put into a 20ml glass test tube with a cap and sealed, to prepare a sample treated under the following treatment conditions. The temperatures shown in tables 2 and 3 were maintained for the times shown in tables 2 and 3 by using an autoclave (ヤマト science, Inc., DN-41), and the sample temperature was set to 30 ℃ over 2 hours.

The results are shown in tables 1 to 3, respectively.

[ Table 1]

The particle size distribution of the conductive polymer composition after the freezing and heating test of example 1 is shown in fig. 1, and further the particle size distribution of the conductive polymer composition after the freezing and heating test of comparative example 1 is shown in fig. 2.

In example 1, no discoloration, a small number of aggregates, and a small particle size were observed and used.

In example 2, the color turned blue, suggesting that the dispersed state of the conductive polymer was changed due to the presence of the sulfur compound derived from the chain transfer agent, but the conductive polymer had a small particle diameter and a small number of aggregates, and could be used.

As is clear from table 1 and fig. 1 and 2, in comparative example 1 and comparative example 2 in which PNVA was not added, the particle size was larger than that in example 1, and aggregation proceeded.

In addition, it was found that in comparative examples 1 and 2, aggregates were more in comparison with example 1.

In comparative example 2, the color turned blue, suggesting that the aggregation state also changed. It is suggested that for the N-vinylpyrrolidone polymer, the polymer changes due to the acidic state of the conductive polymer.

In comparative example 3, a conductive polymer composition containing 1 mass% of an N-vinylcarboxylic acid amide polymer was produced under the same conditions as in patent document 3, but the viscosity was as high as 500mPa · s, and handling as a conductive polymer composition such as transfer was difficult.

[ Table 2]

In comparative example 4 in which PNVA was not added, it was confirmed that the particle size was larger than those in examples 3 and 4, and aggregation proceeded.

[ Table 3]

In example 5 and comparative example 5, in which the concentration of PEDOT-PSS was higher than that in the other examples/comparative examples, an increase in viscosity due to the deterioration test was confirmed. Presumably the intermolecular interaction of PEDOT-PSS.

However, in comparative example 5 in which PNVA was not added, it was confirmed that the particle size was larger than that in example 5, and aggregation proceeded.