JP6273917B2 - Thiophene copolymer and aqueous solution thereof, and thiophene monomer composition and production method thereof - Google Patents

Description

  The present invention relates to a thiophene copolymer, an aqueous solution thereof, a thiophene monomer composition that is a raw material thereof, and a method for producing the same.

  Polymers having π-conjugated double bonds represented by polyacetylene, polythiophene, polyaniline, polypyrrole, etc. are known to become conductors (conductive polymers) by doping with acceptors and donors. Applications to solid electrolytes, conductive paints, electrochromic elements, transparent electrodes, transparent conductive films, chemical sensors, actuators, etc. are being studied. Conventionally, conductive polymers are insoluble and infusible and thus have a problem in molding processability, and it has been necessary to use a polar organic solvent (for example, an amide solvent) having a large environmental load in order to be dissolved. Therefore, there has been a demand for a water-soluble conductive polymer that can be easily molded and dissolved in water with a small environmental load.

  In recent years, PEDOT: PSS, which is a conductive polymer obtained by polymerizing 3,4-ethylenedioxythiophene (EDOT) in the presence of a water-soluble polymer dopant such as polystyrene sulfonic acid (PSS), has been reported (for example, , See Patent Document 1).

  According to Patent Document 1, the polyanion is incorporated as a dopant and water dispersant, so that it becomes water-soluble and the molding processability is improved. However, since the conductive polymer described in Patent Document 1 contains a large amount of a low-conductivity polymer part that is not involved in doping, it has low conductivity and a large excess of sulfo groups, which There are problems such as low water resistance and equipment corrosion due to strong acidity.

  On the other hand, as an alternative method for obtaining a water-soluble conductive polymer, a substituent (for example, a sulfo group, a sulfonate group, etc.) having water solubility and a doping action is covalently bonded directly or via a spacer to a polymer molecular chain. It is proposed to polymerize the compound introduced in step 1 into a water-soluble self-doped conductive polymer excellent in molding processability. For example, poly (4- (2 , 3-Dihydrothieno [3,4-b] [1,4] dioxin-2-ylmethoxy) -1-butanesulfonic acid) (PEDT-S) is reported to exhibit a conductivity of about 10-30 S / cm. (For example, refer to Patent Document 2, Non-Patent Documents 1 and 2).

  However, with the recent high integration of semiconductors, there has been a demand for finer pattern formation, and therefore a polymer having higher conductivity (antistatic ability) has been demanded.

  For this reason, the applicant of the present invention can impart good moldability without adding other components that do not contribute to improvement of conductivity due to water solubilization, have good water solubility and high conductivity, and still have an aqueous solution. In this case, a patent application has already been filed for a self-doped water-soluble conductive polymer having a sufficiently small polymer particle size (see, for example, Patent Document 3). The thiophene monomer for synthesizing this polymer is a sultone compound branched with thieno [3,4-b] -1,4-dioxin-2-methanol according to a known method (for example, see Non-Patent Document 1). Can be easily synthesized.

  However, 2-hydroxymethyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin-5,7-dicarboxylic acid dialkyl ester is an important intermediate for synthesizing this thiophene monomer Is produced, for example, by a method of reacting 3,4-dihydroxythiophene-2,5-dicarboxylic acid ester with epibromohydrin to cyclize the ether, in which case the cyclization product 3 -Hydroxy-3,4-dihydro-2H-thieno [3,4-b] [1,4] dioxepin-6,8-dicarboxylic acid dialkyl ester has a problem of about 30% by-product (for example, , See Patent Document 4).

  Thus, for example, 2-hydroxymethyl-2,3-dihydro-thieno [3,4-b] [1,4] dioxin-5,7-dicarboxylic acid dialkyl ester and 3-hydroxy-3,4-dihydro- 3-Hydroxy-3,4-dihydro-2H by acetylating 2H-thieno [3,4-b] [1,4] dioxepin-6,8-dicarboxylic acid dialkyl ester together and recrystallizing. -It is necessary to purify the target product by removing the acetylated form of thieno [3,4-b] [1,4] dioxepin-6,8-dicarboxylic acid dialkyl ester (see, for example, Patent Document 5), The industrial production method is complicated and accompanied by a significant yield reduction of the target product.

Japanese Patent No. 2636968 Japanese Patent No. 4974095 International Patent Publication No. 2014/007299 US Pat. No. 5,11327 Japanese Patent No. 4049744

Chemisty Materials, 21, 1815-1821 (2009) Advanced Materials, 23 (38), 4403-4408 (2011)

The present invention has been made in view of the above-described background art, and its purpose is as follows.
(1) To provide a novel thiophene monomer composition obtained by an industrial production method, and (2) To provide a novel water-soluble thiophene copolymer having high conductivity,
It is.

  As a result of intensive studies to solve the above problems, the present inventors have obtained the thiophene monomer composition of the present invention by an industrial production method and derived from the thiophene monomer composition of the present invention. The inventors have found that a thiophene copolymer has high conductivity and excellent water solubility, and have completed the present invention.

  That is, this invention relates to the thiophene copolymer as shown below, its aqueous solution, the thiophene monomer composition which is the raw material, and its manufacturing method.

  [1] A thiophene copolymer comprising a structural unit (A) having an ethylenedioxy ring and a structural unit (B) having a propylenedioxy ring, wherein the structural unit (A) is represented by the following formula (1). The structural unit and at least one selected from the group consisting of the structural unit represented by the following formula (2), and the structural unit (B) represented by the following formula (3) and the following formula A thiophene copolymer, which is at least one selected from the group consisting of structural units represented by (4).

[In said formula (1)-(4), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. M represents a hydrogen atom, an alkali metal selected from the group consisting of Li, Na and K, NH (R ¹ ) ₃ or HNC ₅ H ₅ . Each R ¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. ]
[2] The thiophene copolymer according to the above [1], wherein the thiophene copolymer has a weight average molecular weight in the range of 1,000 to 1,000,000 in terms of polystyrene sulfonic acid.

  [3] The above-mentioned [1], wherein the ratio (molar ratio) of the structural unit represented by the formula (1) to the structural unit represented by the formula (2) is at least 70/30. Or the thiophene copolymer as described in [2].

  [4] A thiophene monomer composition comprising a thiophene compound represented by the following formula (5) and a thiophene compound represented by the following formula (6).

[In said formula (5), (6), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. M represents a hydrogen atom, an alkali metal selected from the group consisting of Li, Na and K, NH (R ¹ ) ₃ or HNC ₅ H ₅ . Each R ¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. ]
[5] The above [4], wherein the ratio (molar ratio) of the thiophene compound represented by the above formula (5) to the thiophene compound represented by the above formula (6) is at least 70/30. The thiophene monomer composition described in 1.

  [6] Any of [1] to [3] above, wherein the thiophene monomer composition according to [4] or [5] is polymerized in water or an alcohol solvent in the presence of an oxidizing agent. A method for producing the thiophene copolymer described in 1.

  [7] A thiophene compound represented by the following formula (6).

[In said formula (6), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. M represents a hydrogen atom, an alkali metal selected from the group consisting of Li, Na and K, NH (R ¹ ) ₃ or HNC ₅ H ₅ . Each R ¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. ]
[8] A compound represented by the following formula (7) and a compound represented by the following formula (8) and a compound represented by the following formula (9) are mixed with MH (M is Li, Na or K). In the above [4], the method for producing a thiophene monomer composition, wherein M represents Li, Na, or K.

[In said Formula (9), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. ]
[9] The ratio of the compound represented by the formula (7) to the compound represented by the formula (8) (molar ratio) is at least 70/30. Manufacturing method.

  [10] A water-soluble conductive polymer aqueous solution comprising an aqueous solution of the thiophene copolymer according to any one of [1] to [3].

  [11] A method for producing a conductive coating, comprising applying the aqueous solution according to [10] to a substrate and drying.

  ADVANTAGE OF THE INVENTION According to this invention, the novel thiophene copolymer which has favorable electroconductivity and water solubility sufficient for a shaping | molding process, and the thiophene monomer composition which is the raw material can be provided.

  The thiophene copolymer of the present invention is described in Patent Document 2 in that it has a thiophene portion having a substituent at the α-position of a sulfo group and a 3,4-propylenethiophene portion, and is a copolymer thereof. Unlike PEDT-S, which has a higher conductivity than PEDT-S, it is extremely useful in the industry.

  In addition, the thiophene monomer composition of the present invention is obtained by an industrial production method and can eliminate complicated isolation and purification at the time of monomer synthesis, so that time reduction and yield improvement are expected, and the economic effect is great.

  Hereinafter, the present invention will be described in detail.

The thiophene copolymer of the present invention comprises a structural unit (A) having an ethylenedioxy ring and a structural unit (B) having a propylene dioxy ring,
The structural unit (A) is at least one selected from the group consisting of the structural unit represented by the above formula (1) and the structural unit represented by the above formula (2), and the structural unit (B) is the above It is at least one selected from the group consisting of a structural unit represented by formula (3) and a structural unit represented by formula (4) above;
Is the feature.

  The structural units represented by the above formulas (3) and (4) represent doping states of the structural units represented by the above formulas (1) and (2), respectively.

The dopant causing the insulator-metal transition by doping is divided into an acceptor and a donor. The former enters near the polymer chain of the conductive polymer by doping and takes π electrons from the conjugated system of the main chain. As a result, since positive charges (holes, holes) are injected onto the main chain, it is also called a p-type dopant. Specifically, halogens (Br ₂ , I ₂ , Cl ₂ ), Lewis acid (BF ₃ , PF ₅ , AsF ₅ ), protonic acid (H ₂ SO ₄ , HCl, CF ₃ SO ₃ H), transition metal Examples include halide (FeCl ₃ ), organic substance (TCNQ), and the like.

  The latter is also referred to as an n-type dopant because it gives electrons to the conjugated system of the main chain, which moves in the conjugated system of the main chain. Specific examples include alkali metals (Li, Na, K, Cs), alkylammonium ions, and the like.

  The dopant in the present invention is a sulfo group or a sulfonate group that is covalently bonded in the polymer molecule, and is a p-type dopant. Such a polymer that exhibits conductivity without externally adding a dopant is called a self-doped polymer.

  In said formula (1)-(4), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom.

  The chain or branched alkyl group having 1 to 6 carbon atoms is not particularly limited. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec- Examples include a butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a cyclopentyl group, an n-hexyl group, a 2-ethylbutyl group, a cyclohexyl group, and an n-octyl group.

In the above formulas (1) to (4), M represents an alkali metal selected from the group consisting of a hydrogen atom, Li, Na and K, NH (R ¹ ) ₃ or HNC ₅ H ₅ . At that time, R ¹ is each independently represent a hydrogen atom, or an optionally substituted alkyl group having 1 to 6 carbon atoms. Specific examples of the substituent R ¹ include the same as the above-described substituent R, and more preferably a hydrogen atom or a methyl group. In addition, as the substituent in the case where R ¹ is an alkyl group having a substituent, for example, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, an aryl group having 1 to 20 carbon atoms, a hydroxy group, an amino group, A carboxyl group etc. can be mentioned, More preferably, it is an alkyl group which has hydroxy groups, such as 2-hydroxyethyl group, 3-hydroxypropyl group, 2-hydroxypropyl group, and 2,3-dihydroxypropyl group.

  The thiophene copolymer of the present invention may be a random, block, or alternating copolymer.

  The weight average molecular weight of the thiophene copolymer of the present invention is usually in the range of 1,000 to 1,000,000, preferably in the range of 1,000 to 500,000 in terms of polystyrene sulfonic acid. From the viewpoint of viscosity and water solubility, the range of 1,000 to 100,000 is preferable.

  In the thiophene copolymer of the present invention, the ratio of the structural unit (A) having an ethylenedioxy ring to the structural unit (B) having a propylenedioxythiophene ring [structural unit (A) / structural unit (B)] ( (Molar ratio) is at least 70/30, and is preferably 80/20 or more from the viewpoint of the conductivity of the polymer. More preferably, it is 90/10 or more. Here, the molar ratio is obtained as a ratio of peak areas by gas chromatography or a ratio of peak areas of NMR spectrum.

  The thiophene monomer composition of this invention contains the thiophene compound represented by the said Formula (5), and the thiophene compound represented by the said Formula (6).

  The thiophene monomer represented by the above formula (5) is not particularly limited. For example, 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl ) Sodium methoxy] -1-methyl-1-propanesulfonate, 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-ethyl-1 Sodium propanesulfonate, sodium 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-propyl-1-propanesulfonate, 3- [ (2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-butyl-1-propanesulfonate sodium, 3-[(2,3-dihydrothieno [3, 4-b [1,4] dioxin-2-yl) methoxy] -1-pentyl-1-propanesulfonate sodium, 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2- Yl) methoxy] -1-hexyl-1-propanesulfonate, 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-isopropyl- Sodium 1-propanesulfonate, 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-isobutyl-1-propanesulfonate sodium, 3- [(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-isopentyl-1-propanesulfonate sodium, 3-[(2,3-di Drothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-fluoro-1-propanesulfonate sodium, 3-[(2,3-dihydrothieno [3,4-b] [ 1,4] dioxin-2-yl) methoxy] -1-methyl-1-propanesulfonate potassium, 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl ) Methoxy] -1-methyl-1-propanesulfonic acid, 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-methyl-1- Examples include ammonium propanesulfonate, tri [ammonium 3-[(2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methoxy] -1-methyl-1-propanesulfonate, and the like. .

  The thiophene monomer represented by the above formula (6) is not particularly limited. For example, 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) Sodium 1-methyl-1-propanesulfonate, sodium 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) -1-ethyl-1-propanesulfonate, 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) -1-propyl-1-propanesulfonate sodium, 3- (2,3-dihydrothieno [3,4] -B] [1,4] dioxepin-3-yloxy) -1-butyl-1-propanesulfonic acid sodium, 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxi Pin-3-yloxy) -1-pentyl-1-propanesulfonic acid sodium, 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) -1-hexyl-1 Sodium propanesulfonate, sodium 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) -1-isopropyl-1-propanesulfonate, 3- (2,3 -Dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) -1-isobutyl-1-propanesulfonate sodium, 3- (2,3-dihydrothieno [3,4-b] [1, 4] Sodium dioxepin-3-yloxy) -1-isopentyl-1-propanesulfonate, 3- (2,3-dihydrothieno [3,4-b] [1,4] di Xepin-3-yloxy) -1-methyl-1-propanesulfonic acid, 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) -1-methyl-1- Examples include ammonium propanesulfonate, triethylammonium 3- (2,3-dihydrothieno [3,4-b] [1,4] dioxepin-3-yloxy) -1-methyl-1-propanesulfonate, and the like.

  As a raw material composition of the thiophene copolymer of the present invention, the ratio (molar ratio) of the thiophene compound represented by the above formula (5) to the thiophene compound represented by the above formula (6) is determined by gas chromatography. The ratio of the peak area is at least 70/30, and is preferably 80/20 or more from the viewpoint of the conductivity of the polymer. More preferably, it is 90/10 or more. Here, the molar ratio is obtained as a ratio of peak areas by gas chromatography or a ratio of peak areas of NMR spectrum.

  The thiophene monomer composition of the present invention can be synthesized as follows.

  For example, as described in US Pat. No. 5,11327 (Patent Document 4), the intermediate (7) is obtained by reacting 3,4-dihydroxythiophene-2,5-dicarboxylic acid dimethyl ester with epihalohydrin. And about 70/30 of the intermediate (8).

  Further, as described in Electrochemical Communications, volume 2, pages 72-76 (2000), it is also possible to synthesize by double Williamson reaction with 2,3-dibromo-1-propanol instead of epihalohydrin. Subsequently, (2,3-dihydrothieno [3,4-b] [1,4] dioxin-2-yl) methanol (7) and (3,4-dihydrothieno [3] in all three steps via hydrolysis and decarboxylation. 3,4-b] [1,4] dioxepin) -3-ol (8) can be synthesized.

  Then, for example, with reference to Journal of Electroanalytical Chemistry, 443, 217-226 (1998), the target composition can be synthesized by reacting with the sultone compound (9).

  (First step)

  (Second step)

  (Third process)

  (Fourth process)

  The ratio of the thiophene monomer represented by the above formula (5) and the thiophene monomer represented by the above formula (6) is represented by the intermediate compound represented by the following formula (7) and the following formula (8). Depending on the mixing ratio of the intermediate compound. As a raw material composition of the thiophene monomer composition of the present invention, the ratio (molar ratio) of the intermediate compound represented by the above formula (7) to the intermediate compound represented by the above formula (8) is at least 70. From the viewpoint of the conductivity of the polymer, 80/20 or more is preferable. More preferably, it is 90/10 or more. Further, the upper limit of the molar ratio is preferably as close as possible to 100/0. By purifying by column chromatography, 99.75 / 0.25, further 99.9 / 0.1, The intermediate compound represented by the above formula (8) may be reduced. Here, the molar ratio is obtained as a ratio of peak areas by gas chromatography or a ratio of peak areas of NMR spectrum.

  Furthermore, if necessary, the thiophene monomer represented by the following formula (5) and the thiophene monomer represented by the following formula (6) can be derived into a sulfonic acid in which M is a hydrogen atom by acid treatment. . Furthermore, an ammonium salt can be obtained by amine treatment of this sulfonic acid.

  The thiophene copolymer of the present invention can be produced, for example, by polymerizing the thiophene monomer composition of the present invention in water or an alcohol solvent in the presence of an oxidizing agent.

  The solvent used in the polymerization reaction is water or an alcohol solvent. Although it does not specifically limit as water, For example, a pure water is mentioned, Distilled water and ion-exchange water may be sufficient. The alcohol solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, propanol, and butanol. These alcohol solvents may be used alone or in combination with water. Of these solvents, water or methanol is preferable, and water is more preferable. In addition, the solvent may be replaced with an inert gas such as degassed or nitrogen.

  The amount of the solvent used in the present polymerization reaction is an amount that dissolves the thiophene monomer composition of the present invention, and is not particularly limited, but is 0.1 to 0.1% relative to the charged amount of the thiophene monomer composition of the present invention. The range of 100 times by weight is preferable, and the range of 1 to 20 times by weight is more preferable.

  The oxidizing agent used in the polymerization reaction is one that promotes oxidative polymerization by oxidative dehydrogenation reaction, and is not particularly limited. For example, persulfuric acid, iron salt (III), hydrogen peroxide, hydrogen peroxide, Manganates, dichromates, cerium (IV) sulfate, oxygen and the like can be mentioned. You may use these individually or in mixture of 2 or more types.

  Specific examples of the persulfuric acid include persulfuric acid, ammonium persulfate, sodium persulfate, and potassium persulfate.

Specific examples of the iron salt (III) include FeCl ₃ , Fe ₂ (SO ₄ ) ₃ , iron perchlorate, iron (III) para-toluenesulfonate, and the like. These may use anhydrides or hydrates.

  Specific examples of permanganate include sodium permanganate, potassium permanganate, and magnesium permanganate.

  Specific examples of the dichromate include ammonium dichromate and potassium dichromate.

Among these oxidizing agents, FeCl ₃ , Fe ₂ (SO ₄ ) ₃ , or a combined system of persulfate and iron salt (III) is particularly preferable.

  The amount of the oxidizing agent used in the polymerization reaction is not particularly limited, but is 0.05 with respect to the charged mole number of the mixture of thiophene monomers represented by the above formula (5) and the above formula (6). ~ 50 times mole. More preferably, it is 0.1-10 times mole. More preferably, it is 0.1-5 times mole.

  When the oxidizing agent used in the polymerization reaction is, for example, an iron salt (III) single system, the iron salt (III) is equal to or greater than the mole of the charged thiophene monomer used as a raw material, and is based on the solvent. The polymerization is preferably performed so that the iron concentration is 10% by weight or more. From the viewpoint of doping necessary for developing better conductivity, the iron concentration relative to the solvent is more preferably 20% by weight or more. The “iron concentration” here is a value represented by iron salt / (iron salt + water) × 100 (% by weight), and the iron salt is calculated as an anhydride.

  Further, when the oxidizing agent used in the present polymerization reaction is, for example, a combined system of persulfate and iron salt (III), the persulfate with respect to the number of moles of charged thiophene monomer used as a raw material. Is in the range of 0.5 to 20 times mol, and the iron salt (III) is preferably in the range of 0.01 to 10 times mol, and the persulfate is in the range of 1.5 to 10 times mol. Further, the iron salt (III) is more preferably in the range of 0.05 to 5 times mol.

  In this polymerization reaction, the pressure may be normal pressure, reduced pressure, or increased pressure.

  The reaction atmosphere of the polymerization reaction may be in the air or in an inert gas such as nitrogen or argon. More preferably, it is in an inert gas.

  The reaction temperature of the main polymerization reaction is a temperature at which the thiophene monomer composition of the present invention can be oxidatively polymerized, and is not particularly limited. For example, a range of −10 ° C. to 150 ° C. is preferable, and 0 ° C. to 100 ° C. A range is more preferred. More preferably, it is the range of 5 to 50 degreeC.

  The reaction time of the main polymerization reaction is, for example, a time during which oxidative polymerization of the thiophene monomer composition of the present invention proceeds sufficiently, and is not particularly limited, but is preferably in the range of 0.5 to 200 hours, A range of ˜80 hours is more preferable.

  The reaction method of the present polymerization reaction is not particularly limited. For example, the thiophene monomer composition of the present invention may be made into an aqueous solution, and an oxidizing agent may be dropped slowly or slowly at the same time. The aqueous solution of the thiophene monomer of the present invention may be dropped at once or slowly into the solid or aqueous solution. Moreover, when using 2 or more types of oxidizing agents, you may add each oxidizing agent sequentially.

  The purification method of the thiophene copolymer of the present invention obtained by the main polymerization reaction is not particularly limited. For example, solvent washing, reprecipitation, centrifugal sedimentation, ultrafiltration, dialysis, ion exchange resin treatment, etc. Is mentioned. Each may be performed alone or in combination.

  A typical isolation and purification method of the thiophene copolymer of the present invention is as follows, for example.

  First, the polymer aqueous solution after the polymerization reaction is added to a poor solvent such as acetone to precipitate the polymer, and then the polymer obtained by filtration under reduced pressure is washed with the poor solvent until the filtrate becomes colorless and transparent. After the organic solvent is distilled off by drying, it is treated with a cation exchange resin and converted to an H-type polymer. Examples of the treatment method include a method in which an aqueous solution of the obtained Na salt type polymer is passed through a column filled with a cation exchange resin, a body feed method in which the cation exchange resin is added to the aqueous solution, and the like. In this case, it is preferable to remove the cation exchange resin with a filter paper after the treatment. The aqueous solution thus obtained is subsequently subjected to desalting and removal of unreacted components by ultrafiltration, whereby a desired aqueous conductive polymer solution can be obtained. Further, in the case of obtaining as a solid, the water is subsequently concentrated and distilled off, added to a poor solvent such as acetone and precipitated, and the solid obtained by filtration under reduced pressure is thoroughly washed with the poor solvent and dried under reduced pressure to form an H type. A polymer solid is obtained.

  Furthermore, when forming a salt with various amines, for example, an amine salt type polymer can be easily prepared by adding a stock solution of various amines or an aqueous solution thereof or a solution diluted with an appropriate solvent to an aqueous solution of an H salt type polymer. Can be converted to For example, when treated with aqueous ammonia, the reaction solution is roughly concentrated, the aqueous solution is added to a poor solvent such as acetone to cause polymer precipitation, and then the solid obtained by vacuum filtration is washed with the poor solvent, Ammonium salt type polymer is obtained by drying under reduced pressure.

  In each step of the post-polymerization treatment, centrifugal sedimentation and homogenization treatment may be performed as necessary.

  Although the preparation method of water-soluble conductive polymer aqueous solution is not specifically limited, It is achieved by mixing and dissolving with water at room temperature or under heating (preferably 100 ° C. or less). At that time, a general mixing and dissolving operation using a stirrer chip or a stirring blade can be used. As other methods, ultrasonic irradiation, homogenization treatment (for example, use of a mechanical homogenizer, an ultrasonic homogenizer, a high-pressure homogenizer, etc.) May be performed. In the case of homogenizing treatment, it is preferable to carry out the treatment while cooling in order to prevent thermal degradation of the polymer.

  Next, a water-soluble conductive polymer aqueous solution composed of an aqueous solution of the thiophene copolymer of the present invention will be described.

  The concentration of the thiophene copolymer of the present invention in the water-soluble conductive polymer aqueous solution is not particularly limited, but is usually 50% by weight or less, preferably 20% by weight or less, more preferably 10% from the viewpoint of viscosity. % Or less.

  By making the thiophene copolymer of the present invention into an aqueous solution, it becomes easy to mold into various applications as a water-soluble conductive polymer aqueous solution.

A conductive film can be produced using the thiophene copolymer of the present invention. For example, a conductive film can be easily obtained by applying the above water-soluble conductive polymer aqueous solution to a substrate and drying. Examples of the substrate include glass, plastic, polyester, polyacrylate, polycarbonate, resist substrate, and the like. Examples of the coating method include a casting method, a dipping method, a barcode method, a roll coating method, a gravure coating method, a flexographic printing method, a spray coating method, and an inkjet printing method. It not particularly limited as film ^thickness, but preferably in the range of 10 -2 ~10 ² μm. Although it does not specifically limit as surface resistance value of the coating film obtained, The thing of the range of 1-10 < ⁹ > ohm / square is preferable.

  In the present invention, water solubility sufficient for molding for various uses means that the particle diameter (D50) measured with a particle size distribution analyzer is 10% by weight or less of a polymer aqueous solution prepared at room temperature or under heating. The water solubility is such that it is 20 nm or less and passes through a 0.05 μm filter.

  Moreover, in this invention, favorable electroconductivity means the electroconductivity whose electrical conductivity (electrical conductivity) in a film state is 30 S / cm or more.

  Examples of the polythiophene and thiophene monomer of the present invention are shown below, but the present invention is not construed as being limited to these examples. The analytical instruments and measurement methods used in this example are listed below.

[NMR measurement]
Apparatus: VARIAN, Gemini-200.

[UV-Vis-NIR analysis]
Apparatus: manufactured by SHIMADZU, UV-3100.

[GPC measurement]
Equipment: manufactured by Tosoh Corporation
Column: α-6000 + α-3000,
Detector: UV-8020.
[Surface resistivity measurement]
Apparatus: Loresta GP MCP-T600 manufactured by Mitsubishi Chemical Corporation.

[Film thickness measurement]
Apparatus: DEKTAK XT manufactured by BRUKER.

[Particle size measurement]
Apparatus: Nikkiso Co., Ltd. Microtrac Nanotrac UPA-UT151.

[Viscosity measurement]
Complete viscometer / BROOKFIELD VISCOMETER DV-1 Prime.

Synthesis Example 1 Synthesis of a mixture of the compound represented by the above formula (7) / the compound represented by the above formula (8) = 95/5.
<First Step: Synthesis of Composition of Compound Represented by Formula (10) and Compound Represented by Formula (11)>
Under a nitrogen atmosphere, 92.8 g (399.6 mmol) of 3,4-dihydroxythiophene-2,5-dicarboxylic acid dimethyl ester was added to a 5-liter three-necked flask equipped with a stirrer, a thermometer, and a condenser. , 3-dibromopropanol 200.9 g (921.9 mmol), potassium carbonate 110.6 g (800.1 mmol), and dimethyl sulfoxide 909.3 g were charged, and heating and stirring were continued at 80 ° C. for 24 hours. After completion of the reaction, the obtained reaction solution was concentrated, diluted with a dichloromethane-methanol mixture, the precipitated salt was filtered, and the solvent was replaced with 650.1 g of ethanol while re-concentrating to obtain 877.4 g of a black-brown slurry solution. Got. As a result of analyzing the slurry solution by gas chromatography, the production ratio (molar ratio) of the thiophene compound (10) having an ethylenedioxy ring to the thiophene compound (11) having a propylenedioxy ring is a peak by gas chromatography. The area ratio was 95/5, and the combined quantitative yield by the internal standard method was 84.2%.

<Second Step: Synthesis of Composition of Compound Represented by Formula (12) and Compound Represented by Formula (13)>
In a 2 liter three-necked flask equipped with a stirrer, a thermometer, and a condenser tube, obtained in the first step under a nitrogen atmosphere: 45.7 g of the composition of the compound (10) and the compound (11) When 58.4 g (1.4 mol) of 96% sodium hydroxide was dissolved in 974.5 g of water and added to 438.7 g of an ethanol slurry containing (158.6 mmol), the mixture was heated and refluxed for 2 hours. The peaks of compound (10) and compound (11) disappeared by HPLC analysis. After completion of the reaction, the obtained reaction solution was concentrated, diluted with 193.0 g of water, cooled to 3 ° C., 321.2 g (3.1 mol) of 35% hydrochloric acid was added, and the mixture was stirred for 2 hours. The precipitate crystallized out. The precipitate was filtered, washed with water and dried to obtain a composition of compound (12) and compound (13) as 35.1 g of a light brown solid. The combined isolation yield of both was 80.2% (134.9 mmol).

<Third Step: Synthesis of Composition of Compound Represented by Formula (7) and Compound Represented by Formula (8)>
In a 1 liter three-necked flask equipped with a stirrer, a thermometer, and a condenser tube, 34.0 g (130) of the composition of the compound (12) and the compound (13) obtained in the second step under a nitrogen atmosphere. 0.7 mmol) and 66,8 g of N, N-dimethylformamide were added with 2.1 g (26.2 mmol) of copper (II) oxide, the temperature was raised, and heating and stirring were continued for 16 hours. After completion of the reaction, the obtained reaction solution was concentrated, dissolved in 750 ml of ethyl acetate, and then filtered. The obtained filtrate was washed with 4.1 g (39.1 mmol) of 35% hydrochloric acid and 20 ml of saturated brine, further washed with 350 ml and 25 ml of saturated brine, concentrated, treated with silica gel at the origin, and re-concentrated. 20.5 g of a transparent pale orange solid was obtained. As a result of analyzing the pale orange solid by gas chromatography, the peaks of the compound (7) and the compound (8) as the target compounds were confirmed. The production ratio (molar ratio) of compound (7) to compound (8) was 95/5 as the ratio of the peak area by gas chromatography. As a result of the quantification, the combined content was 19.4 g (112.5 mmol, yield 86.1%). As a result, the overall yield from the first step to the third step was 58.1%.

Synthesis Example 2
A 95/5 composition of Compound (7) and Compound (8) obtained in Synthesis Example 1 was purified by column chromatography with an eluent of toluene / ethyl acetate (4/1), and Compound (11) and Compound ( 12) 99.75 / 0.25 mixture was obtained.

Example 1 Synthesis of thiophene monomer composition [compound represented by the following formula (14) / compound represented by the following formula (15) = composition of 95/5]
In a nitrogen atmosphere, 60% sodium hydride (5.71 g, 142.7 mmol) and toluene (425 ml) were charged into a 1 L separable flask, and then the composition of compound (7) and compound (8) obtained in Synthesis Example 1 above. 20.0 g (115.1 mmol) was dissolved in 199 g of toluene and added. Thereafter, the reaction solution was heated to the reflux temperature and stirred at the same temperature for 1 hour. Thereafter, a mixed solution composed of 16.50 g (115.1 mmol) of 2,4-butane sultone and 109 g of toluene was dropped, and the mixture was stirred at the same temperature for 2 hours. After cooling, 293 mL of acetone was added to the resulting reaction solution and stirred overnight. Subsequently, the reaction solution was added to 1.4 L of acetone and stirred under cooling. By filtering and vacuum-drying the crystallized powder, the thiophene monomer composition (A) which is a composition of the target compound represented by the following formula (14) and the compound represented by the following formula (15) Was obtained as 19.5 g of a pale yellow powder (yield 51%). From NMR, it was confirmed to be the target product. The ratio (molar ratio) of the compound represented by the following formula (14) to the compound represented by the following formula (15), determined from the proton ratio (δ6.5 ppm / 6.7 ppm) of NMR analysis, was 95. / 5.

¹ H-NMR (D ₂ O, 3- (Trimethylsilyl) propionic-2,2,3,3-d4 acid sodium salt) δ (ppm); 6.73 (s, proton of thiophene ring of the following formula (14) , 0.1H), 6.52 (s, proton of the thiophene ring of the following formula (13), 1.9H), 4.43-4.26 (m, 2H), 4.15-4.05 (m , 1H), 3.77-3.68 (m, 4H), 3.05-2.97 (m, 1H), 2.34-2.17 (m, 1H), 1.79-1.64. (M, 1H), 1.32 (d, 3H).

Example 2 Synthesis of a copolymer aqueous solution of the thiophene monomer composition (95/5) obtained in Example 1.
To a 1 L separable flask, 19.00 g (57.5 mmol) of a thiophene monomer composition synthesized according to Example 1 and 285 g of water were added. After dissolution, 5.60 g (34.5 mmol) of anhydrous iron (III) chloride was added at room temperature and stirred for 20 minutes. Thereafter, a mixed solution consisting of 27.39 g (115.0 mmol) of sodium persulfate and 190 g was added dropwise while maintaining the reaction solution temperature at 30 ° C. or lower. After stirring at room temperature for 3 hours, the reaction solution was dropped into 1.6 kg of acetone to precipitate a black Na-type polymer. The polymer was filtered and vacuum dried to obtain 25.3 g of a crude polymer.

  Next, 1.3 kg of an aqueous solution prepared by adding water to this crude polymer to make a 2 wt% solution was passed through a column packed with 670 ml of a cation exchange resin [Lewatit MonoPlus S100 (H type), manufactured by LANXESS) (space). Speed = 0.8) to obtain 2.1 kg of an H-type polymer aqueous solution. Further, by purifying the polymer aqueous solution by cross-flow ultrafiltration (filter = Vivaflow 200, fractional molecular weight = 10,000, permeation rate = 16), the structural unit (A) having an ethylenedioxy ring and A thiophene copolymer comprising a structural unit (B) having a propylenedioxy ring, wherein the structural unit (A) is a structural unit represented by the following formula (16) and a structure represented by the following formula (17): And at least one selected from the group consisting of units, and the structural unit (B) is at least selected from the group consisting of a structural unit represented by the following formula (18) and a structural unit represented by the following formula (19): 1.4 kg of a dark blue aqueous solution of a kind of thiophene copolymer was synthesized. Subsequently, the aqueous polymer solution was concentrated to a solid content of 2% to obtain 693 g (yield 72%).

  The surface resistance, film thickness, and conductivity of a film obtained by casting the obtained aqueous polymer solution on an alkali-free glass plate (25 mm square) were 69Ω / □, 3.0 μm, and 48 S / cm, respectively. This value was about twice as high as the conductivity of PEDT-S. Further, the particle size (D50) of the polymer in a 2.0 wt% aqueous solution was 1.1 nm, and the viscosity was 9.6 mPa · s (20 ° C.).

Example 3 Synthesis of thiophene monomer composition [mixture of the above general formula (13) / the above general formula (14) = 99.75 / 0.25]
Except for using the 99.75 / 0.25 composition of Compound (7) and Compound (8) obtained according to Synthesis Example 2, the procedure was performed in accordance with Example 1, and the target compound (13) and A 99.75 / 0.25 composition with compound (14) was obtained.

Example 4 Synthesis of an aqueous copolymer solution of the thiophene monomer composition (99.75 / 0.25) obtained in Example 3.
The same procedure as in Example 2 was performed except that the thiophene monomer obtained in Example 3 was used. The surface resistance, film thickness, and conductivity of the film obtained by casting the obtained aqueous polymer solution on an alkali-free glass plate (25 mm square) were 68Ω / □, 1.4 μm, and 105 S / cm, respectively. This value was about three times higher than the conductivity of PEDT-S. Further, the particle size (D50) of the polymer in the 2.0 wt% aqueous solution was 1.1 nm, and the viscosity was 15.4 mPa · s (20 ° C.).

Comparative Example 1 Synthesis of a polymer containing a structure represented by the following formula (21) or the following formula (22).
Chemistry Materials, 21, 1815-1821 (2009) or Advanced Materials, 23 (38), 4403-4408 (2011) were synthesized according to the following scheme.

(1A) Synthesis of compound (20).
In a 100 mL eggplant flask, the compound represented by the above formula (8) is N.I. 1.83 g of D (Not-detected) compound (7), 45 mL of toluene, and 0.32 g (13.2 mmol) of 60% NaH were charged and reacted for 1 hour under reflux conditions. 1.46 g (10.7 mmol) of 1,4-butane sultone dissolved in 12 mL of toluene was added dropwise under reflux. After further aging for 2 hours, the mixture was cooled to room temperature and added to 200 mL of acetone to precipitate a jelly-like solid. After filtration through filter paper, drying under reduced pressure gave 2.0 g of the target compound (20) as a light brown solid (yield 56%).

  (1B) Synthesis of a polymer containing the structural unit represented by the above formula (21) or the above formula (22).

A 50 mL Schlenk tube was charged with 0.378 g (1.15 mmol) of the compound (20) obtained above and 5.7 mL of water to obtain an aqueous monomer solution. A mixed solution consisting of 0.113 g (0.70 mmol) of FeCl _3, 0.554 g (2.33 mmol) of sodium persulfate and 3.8 ml of water was sequentially added thereto and stirred at room temperature for 3 hours.

  The obtained polymerization solution was poured into 76 ml of acetone to precipitate a polymer. The obtained slurry was subjected to centrifugal sedimentation (3000 rpm) to obtain 0.74 g of a black solid. Subsequently, after adding water to a black solid to prepare a 1% aqueous solution, 8.0 g of a cation exchange resin [Lewatit MonoPlus S100 (H type), manufactured by LANXESS) was added and stirred for 3 hours to prepare an H type polymer solution. Obtained. The ion exchange resin was removed by filtration, and the resulting mother liquor was further subjected to dialysis treatment (dialysis membrane: Spectrum Laboratories, Spectra / Por MWCO = 3500) to remove inorganic salts. The aqueous solution containing the purified H-type polymer was concentrated to 4.3 g, and the obtained residue was poured into 80 ml of acetone to precipitate a polymer. The obtained slurry was subjected to centrifugal sedimentation (3000 pm) to obtain 0.188 g of an H-type polymer (yield = 49%).

  The conductivity of a film obtained by preparing a 0.5 wt% aqueous solution of the obtained polymer and casting it on an alkali-free glass plate was 22 S / cm. The particle size (D50) of the polymer in the 0.5 wt% aqueous solution was below the detection limit (0.8 nm).

  The thiophene monomer composition of the present invention can be used, for example, as a monomer for conductive polymer polythiophenes used for applications such as antistatic materials, solid electrolytes of solid electrolytic capacitors, solar cells, organic EL, capacitors, chemical sensors and the like. In particular, since the thiophene monomer composition of the present invention has a sulfo group having water solubility and a role as an intramolecular dopant, the resulting polymer is expected to be a water-soluble self-doping conductive polymer. Is done.

  The thiophene copolymer of the present invention can be applied to, for example, antistatic agents, capacitor solid electrolytes, conductive paints, electrochromic elements, transparent electrodes, transparent conductive films, chemical sensors, and actuators. In particular, since it is water-soluble, damage to the fat-soluble resist is small, and peeling cleaning is easy. Therefore, it is expected to be used as an antistatic film forming material for suppressing resist charging during electron beam lithography. . In addition, since the polymer particle diameter is very small when an aqueous solution is used, for example, it is considered that the aluminum solid electrolytic capacitor has good permeability to the etched aluminum foil that has been subjected to chemical conversion treatment. The area is improved, and the performance of the capacitor is expected to be improved, such as increasing the capacitance and lowering the ESR.

Claims (10)

A thiophene copolymer comprising a structural unit (A) having an ethylenedioxy ring and a structural unit (B) having a propylenedioxy ring, wherein the structural unit (A) is represented by the following formula (1) The structural unit is at least one selected from the group consisting of a unit and a structural unit represented by the following formula (2), and the structural unit (B) is a structural unit represented by the following formula (3) and the following formula (4): A thiophene copolymer, which is at least one selected from the group consisting of structural units represented by:

[In said formula (1)-(4), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. M represents a hydrogen atom, an alkali metal selected from the group consisting of Li, Na and K, NH (R ¹ ) ₃ or HNC ₅ H ₅ . Each R ¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. ] The thiophene copolymer according to claim 1, wherein the thiophene copolymer has a weight average molecular weight in the range of 1,000 to 1,000,000 in terms of polystyrene sulfonic acid. A thiophene monomer composition comprising a thiophene compound represented by the following formula (5) and a thiophene compound represented by the following formula (6).

[In said formula (5), (6), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. M represents a hydrogen atom, an alkali metal selected from the group consisting of Li, Na and K, NH (R ¹ ) ₃ or HNC ₅ H ₅ . Each R ¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. ] The thiophene according to claim 3 , wherein a ratio (molar ratio) of the thiophene compound represented by the formula (5) to the thiophene compound represented by the formula (6) is at least 70/30. Monomer composition. The thiophene copolymer composition according to claim 1 or 2 , wherein the thiophene monomer composition according to claim 3 or 4 is polymerized in water or an alcohol solvent in the presence of an oxidizing agent. Manufacturing method. The thiophene compound represented by following formula (6).

[In said formula (6), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. M represents a hydrogen atom, an alkali metal selected from the group consisting of Li, Na and K, NH (R ¹ ) ₃ or HNC ₅ H ₅ . Each R ¹ independently represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. ] A compound represented by the following formula (7) and a compound represented by the following formula (8) and a compound represented by the following formula (9) are MH (M represents Li, Na or K). The method for producing a thiophene monomer composition according to claim 3, wherein M represents Li, Na, or K.

[In said Formula (9), R represents a C1-C6 linear, branched alkyl group, or a fluorine atom. ] The production method according to claim 7 , wherein a ratio (molar ratio) of the compound represented by the formula (7) to the compound represented by the formula (8) is at least 70/30. A water-soluble conductive polymer aqueous solution comprising an aqueous solution of the thiophene copolymer according to claim 1 or 2 . A method for producing a conductive film, wherein the aqueous solution according to claim 9 is applied to a substrate and dried.