Method for preparing functionalized polythiophenes

Abstract

A method is provided for producing a liquid composition comprising a functionalized π-conjugated polythiophene. The functionalized π-conjugated polythiophene has the general formula (I): 1 and R 1 is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms, and A is an organic residue having an anionic functional group), and the liquid composition comprises a repeating unit of the formula (wherein R is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms, and A is an organic residue having an anionic functional group), and can be obtained by a step of adjusting the pH value of the liquid phase to a value in the range of 2.5 to 10 by adding a base; a liquid composition comprising a functionalized π-conjugated polythiophene, which is characterized by a certain weight loss at a given minimum temperature after drying; a method for preparing a laminate in which these liquid compositions are used for forming a conductive layer; a laminate obtainable by this method; and the use of the liquid composition for preparing a conductive layer in an electronic device. TIFF2026041860000012.tif14128

Description

[Technical Field]

[0001] The present invention relates to a method for producing a liquid composition comprising a functionalized π-conjugated polythiophene, to a liquid composition obtainable by this method, to a liquid composition comprising a functionalized π-conjugated polythiophene, which liquid composition is characterized by a certain weight loss at a given minimum temperature after drying, to a method for preparing layered bodies in which these liquid compositions are used for the formation of a conductive layer, to a laminate obtainable by this method, and to the use of the liquid composition for the preparation of a conductive layer in an electronic device.

[0002] Commercially available electrolytic capacitors are typically constructed from a porous metal electrode, an oxide layer on the metal surface that functions as a dielectric, a typically solid electrically conductive material introduced into the porous structure, an external electrode (contact), such as a silver layer, additional electrical contacts, and a seal. A frequently used electrolytic capacitor is the tantalum electrolytic capacitor, in which the anode electrode is made of the valve metal tantalum, on which a uniform dielectric layer of tantalum pentoxide is formed by anodization (also called "forming"). A liquid or solid electrolyte forms the cathode of the capacitor. Aluminum capacitors are even more commonly used, in which the anode electrode is made of the valve metal aluminum, on which a uniform, electrically insulating aluminum oxide layer is formed as a dielectric by anodization. Again, a liquid or solid electrolyte forms the cathode of the capacitor. Aluminum capacitors are typically constructed as wound or stacked capacitors.

[0003] Due to their high electrical conductivity, π-conjugated polymers are particularly suitable as solid electrolytes in the aforementioned capacitors. π-conjugated polymers are also called conductive polymers or synthetic metals. Because polymers offer advantages over metals in terms of processability, weight, and targeted adjustment of properties through chemical modification, π-conjugated polymers are becoming increasingly economically important. Examples of known π-conjugated polymers are polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene, and poly(p-phenylene-vinylene). A particularly important polythiophene used industrially is poly(3,4-ethylenedioxythiophene) (PEDOT), due to its very high electrical conductivity in its oxidized form.

[0004] Solid electrolytes based on conductive polymers can be applied to oxide layers in various ways. For example, EP 0 340 512 A describes the preparation of a solid electrolyte from 3,4-ethylenedioxythiophene and its use in electrolytic capacitors. According to the teachings of this publication, 3,4-ethylenedioxythiophene is polymerized in situ on the oxide layer. In addition to in situ polymerization, methods for preparing solid electrolytes in capacitors are also known in the prior art, in which a dispersion containing already polymerized thiophene and a polyanion as counterion, such as the prior art PEDOT / PSS dispersion (PEDOT = poly(3,4-ethylenedioxythiophene, PSS = polystyrene sulfonate), is applied to the oxide layer, and the dispersant is then removed by evaporation. Such a method for preparing solid electrolytic capacitors is disclosed, for example, in DE 10 2005 043 828 A.

[0005] However, PEDOT / PSS dispersions are characterized by the drawback of containing a significant amount of PSS as a non-conductive inactive material. Furthermore, the presence of PSS can result in PEDOT / PSS particles in the dispersion being too large to reliably penetrate the smaller pores of porous metal electrodes. Finally, the maximum solids content of PEDOT / PSS dispersions is often limited to values ​​of approximately 3 wt%. To overcome these drawbacks, liquid compositions containing PEDOT derivatives that do not feature the drawbacks of known PEDOT / PSS dispersions have been prepared. Polythiophenes functionalized with sulfonate groups were first developed. The sulfonate groups allow these polythiophenes to self-dope and do not require counterions such as PSS. For example, European Patent Application Publication No. 1122274(A1) discloses the preparation of functionalized π-conjugated polymers such as poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid) (PEDOT-S) by oxidative polymerization of the corresponding monomer 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid (EDOT-S). However, the conductivity of the conductive layers prepared with the polymer solutions obtained in EP 1 122 274 A1 is usually too low to allow these polymer solutions to be used, for example, for preparing solid electrolyte layers in solid electrolytic capacitors. Functionalized π-conjugated polymers such as PEDOT-S with significantly increased conductivity and methods for their preparation are disclosed in WO 2016 / 102129 A1.

[0006] Conductive polymers used to produce conductive layers in electronic components, such as solid electrolyte layers in capacitors, should be characterized not only by a sufficiently high electrical conductivity but also by a high thermal stability, since high thermal stresses occur, for example, during the soldering of capacitors or in the subsequent use of the electronic components, for example in the automotive industry.

[0007] It was therefore an object of the present invention to overcome the drawbacks of the prior art in the field of π-conjugated polymers.

[0008] In particular, it was an object of the present invention to provide a composition comprising a π-conjugated conductive polymer, preferably a water-soluble or water-dispersible π-conjugated conductive polymer, characterized in that it not only exhibits a higher electrical conductivity compared to corresponding compositions known from the prior art, but also exhibits an increased thermal stability of the π-conjugated conductive polymer. The term "thermal stability" as used herein preferably characterizes the ability of the conductive polymer to withstand weight loss as a result of thermal decomposition.

[0009] It was also an object of the present invention to provide a composition comprising a π-conjugated conductive polymer, preferably a water-soluble or water-dispersible π-conjugated conductive polymer, which, when used for the formation of a solid electrolyte layer in a capacitor, leads to advantageous properties of the capacitor, in particular increased thermal stability, compared to capacitors in which the solid electrolyte layer has been prepared using corresponding compositions known from the prior art.

[0010] A contribution to solving at least one of the above-mentioned objects is provided by the subject matter of the independent claims which form a category, and the dependent claims which depend therefrom represent preferred embodiments of the invention, the subject matter of which likewise contributes to solving at least one of the above-mentioned objects.

[0011] |1a| A contribution to solving at least one of the objects according to the present invention is a method 1 for producing a liquid composition comprising a functionalized π-conjugated polythiophene, comprising: i) providing a liquid phase comprising a functionalized π-conjugated polythiophene dissolved or dispersed in a solvent, the functionalized π-conjugated polythiophene having the general formula (I): [ka] (In the formula, X and Y are the same or different and are O, S, or NR 1 and R 1 is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms, A is an organic residue having an anionic functional group, providing a liquid phase, the liquid phase having a pH value of less than 2.5, preferably less than 2.0; ii) adjusting the pH value of the liquid phase provided in process step i) to a value in the range from 2.5 to 10, preferably in the range from 3 to 8, by adding a base.

[0012] |2a| In a preferred embodiment of method 1 according to the present invention, in general formula (I), X and Y are O, A is -(CR 2 2) m -CR 2 R 3 -(CR 2 2) n - (In the formula, residue R 2 are, independently of each other, hydrogen or -(CH2) s -Z-(CR 4 2) p -SO3 - M + and R 3 is -(CH2) s -Z-(CR 4 ) p -SO3 - M + and Z is O, S or -CH2-; R 4is hydrogen or an alkyl group, M + is a cation, m and n are the same or different and are integers of 0 to 3; s is an integer from 0 to 10, and p is an integer from 1 to 18.

[0013] "Residue R 2 are, independently of each other, hydrogen or -(CH2) s -Z-(CR 4 2) p -SO3 - M + The term "is" refers to the fact that at a given carbon atom, both residues R 2 can be hydrogen or both residues R 2 -(CH2) s -Z-(CR 4 2) p -SO3 - M + or one residue R 2 can be hydrogen and one residue R 2 -(CH2) s -Z-(CR 4 2) p -SO3 - M + Furthermore, in a given functionalized π-conjugated polythiophene, the residue -(CH2) s -Z-(CR 4 2) p -SO3 - M + does not necessarily have to be the same.

[0014] This preferred embodiment is a second embodiment of the method 1 according to the invention, which is preferably subordinate to the first embodiment.

[0015] |3a| In a further preferred embodiment of method 1 according to the present invention, in general formula (I), X and Y are O, A is -(CH2) s -CR 2 R 3-(CH2) n - (In the formula, R 2 is hydrogen, R 3 is -(CH2)-O-(CH2) p -SO3 - M + and M + is an inorganic cation, preferably Na + or K + and n is 0 or 1, s is 0 or 1, p is 4 or 5).

[0016] This preferred embodiment is a third embodiment of the method 1 according to the invention and is preferably subordinate to the second embodiment.

[0017] |4a| In a further preferred embodiment of method 1 according to the present invention, in general formula (I), X and Y are O, A is -(CH2) s -CR 2 R 3 -(CH2) n - (In the formula, R 2 is hydrogen, R 3 is -(CH2) s -O-CH2-CH2-CHR 4 -SO3 - M + and M + is an inorganic cation, preferably Na + or K + and R 4 is CH3 or CH2CH3, preferably CH3, n is 0 or 1, s is 0 or 1, p is 4 or 5).

[0018] This preferred embodiment is a fourth embodiment of the method 1 according to the invention and is preferably subordinate to the second embodiment.

[0019] |5a| In a further preferred embodiment of Method 1 according to the present invention, the π-conjugated polythiophene is poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid) or a salt thereof, poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-2-butanesulfonic acid) or a salt thereof, or a mixture of these polymers. This preferred embodiment is a fifth embodiment of Method 1 according to the present invention, and preferably depends from any one of the first to fourth embodiments.

[0020] |6a| In a further preferred embodiment of Method 1 according to the invention, the solvent is selected from the group consisting of water, aliphatic alcohols such as methanol, ethanol, isopropanol and butanol, diacetone alcohol, ethylene glycol and glycerol, aliphatic ketones such as acetone and methyl ethyl ketone, aliphatic nitrites such as acetonitrile, glycol ethers such as polyethylene glycol methyl ether, and mixtures of at least two of these solvents, in particular mixtures of water and water-miscible solvents, with water being most preferred as the solvent. This preferred embodiment is a sixth embodiment of Method 1 according to the invention, preferably subordinate to any one of the first to fifth embodiments.

[0021] |7a| In a further preferred embodiment of method 1 according to the invention, the base is an inorganic base, such as an alkali metal hydroxide or alkaline earth metal hydroxide, more preferably an inorganic base selected from the group consisting of ammonia, lithium hydroxide, lithium oxide, sodium hydroxide, sodium oxide, potassium hydroxide, potassium oxide, calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, barium hydroxide, barium oxide, lithium silicate, sodium silicate, potassium silicate, lithium borate, sodium borate, potassium borate, lithium carbonate, sodium carbonate, potassium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, trisodium phosphate, and a mixture of at least two of these bases. This preferred embodiment is a seventh embodiment of method 1 according to the invention, which is preferably subordinate to any one of the first to sixth embodiments.

[0022] In a further preferred embodiment of method 1 according to the invention, the base is an alkali metal hydroxide, preferably an alkali metal hydroxide selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide and a mixture of at least two of these bases. This preferred embodiment is an eighth embodiment of method 1 according to the invention, which is preferably subordinate to the seventh embodiment.

[0023] In a further preferred embodiment of the method 1 according to the invention, the liquid phase provided in method step i) comprises the functionalized π-conjugated polythiophene in an amount in the range of 0.1 to 25% by weight, preferably in the range of 0.25 to 10% by weight, most preferably in the range of 0.5 to 4% by weight, in each case based on the total weight of the liquid phase. This preferred embodiment is a ninth embodiment of the method 1 according to the invention, which is preferably dependent on any one of the first to eighth embodiments.

[0024] |10a| In a further preferred embodiment of the method 1 according to the invention, the functionalized π-conjugated polythiophene in the liquid phase provided in method step i) has a weight average molecular weight M of at least 6, preferably at least 8, more preferably at least 10, more preferably at least 12, more preferably at least 14, more preferably at least 16, more preferably at least 18, more preferably at least 20. w Molar average molecular weight M n Ratio to (M w / M n This preferred embodiment is a tenth embodiment of the method 1 according to the present invention, and preferably depends on any one of the first to ninth embodiments.

[0025] |11a| In a further preferred embodiment of the method 1 according to the invention, the functionalized π-conjugated polythiophene in the liquid phase provided in method step i) has a weight average molecular weight M of at least 50 000 g / mol, preferably at least 75 000 g / mol, more preferably at least 100 000 g / mol, most preferably at least 125 000 g / mol. w This preferred embodiment is an eleventh embodiment of the method 1 according to the invention, which is preferably dependent on the tenth embodiment.

[0026] |12a| In a further preferred embodiment of the method 1 according to the invention, the functionalized π-conjugated polythiophene in the liquid phase provided in method step i) has a weight average molecular weight M in the range of 125000 g / mol to 240000 g / mol, preferably in the range of 125000 g / mol to 210000 g / mol. w This preferred embodiment is the twelfth embodiment of the method 1 according to the invention, and is preferably dependent on the tenth or eleventh embodiment.

[0027] |13a| In a further preferred embodiment of the method 1 according to the invention, the functionalized π-conjugated polythiophene in the liquid phase provided in method step i) has a molar average molecular weight M of less than 25000 g / mol, preferably less than 20000 g / mol, more preferably less than 15000 g / mol. nThis preferred embodiment is a thirteenth embodiment of the method 1 according to the present invention, and preferably depends on any one of the tenth to twelfth embodiments.

[0028] |14a| In a further preferred embodiment of the method 1 according to the invention, the preparation of the liquid phase in method step i) comprises: ia) a) General formula (I) [ka] wherein X, Y and A are defined as above; and b) an oxidizing agent; c) providing a liquid reaction mixture comprising a solvent; ib) a process step of oxidatively polymerizing the thiophene monomer of general formula (I) in the liquid reaction mixture obtained in process step ia) to obtain a liquid phase comprising a functionalized π-conjugated polythiophene; ic) optionally, the process step of purifying the liquid phase obtained in process step ib), preferably by ionic filtration.

[0029] This preferred embodiment is a fourteenth embodiment of the method 1 according to the present invention, and is preferably dependent on any one of the first to thirteenth embodiments.

[0030] |15a| In a preferred embodiment of the fourteenth embodiment of method 1 according to the invention, the pH of the liquid reaction mixture provided in method step ia) is adjusted to a value below 2.5 using an organic or inorganic acid, preferably an acid selected from the group consisting of formic acid, acetic acid, lactic acid, propionic acid, citric acid, malic acid, fumaric acid, sulfuric acid, sulfonic acid, nitric acid, phosphonic acid, phosphoric acid, or a mixture of at least two of these acids, the use of sulfuric acid being particularly preferred. This preferred embodiment is a fifteenth embodiment of method 1 according to the invention, which is preferably subordinate to the fourteenth embodiment.

[0031] In a further preferred embodiment of the fourteenth embodiment of the method 1 according to the invention, the oxidative polymerization in method step ib) is carried out under an inert gas atmosphere of nitrogen, argon, carbon dioxide or a mixture thereof. This preferred embodiment is the sixteenth embodiment of the method 1 according to the invention, which is preferably dependent on the fourteenth or fifteenth embodiment.

[0032] In a further preferred embodiment of the fourteenth embodiment of the method 1 according to the invention, the oxidative polymerization in method step ib) is carried out under a pressure equal to or greater than the vapor pressure of the liquid reaction mixture during the polymerization reaction in method step ib). This preferred embodiment is the seventeenth embodiment of the method 1 according to the invention, which is preferably dependent on any one of the fourteenth to sixteenth embodiments.

[0033] In a further preferred embodiment of the 14th embodiment of the method 1 according to the invention, the oxidative polymerization in method step ib) is carried out under reduced pressure of 0.8 bar or less. This preferred embodiment is the 18th embodiment of the method 1 according to the invention, which is preferably dependent on any one of the 14th to 17th embodiments.

[0034] In a further preferred embodiment of the 14th embodiment of the method 1 according to the invention, the liquid phase obtained in process step ib) is purified in a further process step ic). This preferred embodiment is the 19th embodiment of the method 1 according to the invention, which is preferably dependent on any one of the 14th to 18th embodiments.

[0035] In a further preferred embodiment of the fourteenth embodiment of the method 1 according to the invention, purification in method step ic) is achieved by filtration and / or by treatment with an ion exchanger. This preferred embodiment is the twentieth embodiment of the method 1 according to the invention, which is preferably subordinate to the nineteenth embodiment.

[0036] In a further preferred embodiment of the method 1 according to the invention, the liquid phase provided in method step i) comprises further additives, preferably selected from the group consisting of surface-active substances, adhesion promoters, additives that increase the conductivity, organic binders or a mixture of at least two of these further additives. This preferred embodiment is a 21st embodiment of the method 1 according to the invention, which is preferably dependent on any one of the 1st to 20th embodiments.

[0037] |1b| A contribution to solving at least one of the objects according to the invention is also made by a first embodiment of a liquid composition 1 comprising a functionalized π-conjugated polythiophene, which can be obtained by a method 1 according to the invention, preferably by a method 1 according to any one of the first to twentieth embodiments.

[0038] |2b| In a preferred embodiment of liquid composition 1 according to the present invention, the composition obtained after drying liquid composition 1 at a temperature of 100°C and a pressure of 50 mbar for 16 hours is a composition obtained by subjecting liquid composition 1 to the following conditions (A) to (E): (A) a weight loss of 10 wt. % based on the total weight of the dried liquid composition at a temperature of 300° C. or greater, preferably 310° C. or greater, and even more preferably 320° C. or greater, as measured by thermogravimetric analysis; (B) a weight loss of 20 wt. % based on the total weight of the dried liquid composition at a temperature of 330° C. or greater, preferably 335° C. or greater, and even more preferably 340° C. or greater, as measured by thermogravimetric analysis; (C) a weight loss of 30 wt. % based on the total weight of the dried liquid composition at a temperature of 345°C or greater, preferably 350°C or greater, and even more preferably 355°C or greater, as measured by thermogravimetric analysis; (D) There is no peak in the differential plot between 250°C and 270°C. (E) At least one of the following conditions is satisfied: the ratio of the derivative at 261°C to the derivative at the second peak is 0.1 or less, preferably 0.08 or less, and more preferably 0.07 or less.

[0039] This preferred embodiment is a second embodiment of the liquid composition 1 according to the invention and is preferably dependent on the first embodiment. In this context, it is particularly preferred that the dried liquid composition 1 fulfills the following conditions or combinations of conditions: A, B, C, D, E, AB, AC, AD, AE, BC, BD, BE, CD, CE, DE, ABC, ABD, ABE, ACD, ACE, ADE, BCD, BCE, BDE, CDE, ABCD, ABCE, ABDE, ACDE, BCDE and ABCDE.

[0040] In a further preferred embodiment of liquid composition 1 according to the present invention, the conductive layer produced by the liquid composition has a conductivity of more than 25 S / cm. This preferred embodiment is a third embodiment of liquid composition 1 according to the present invention, and is preferably dependent on the first or second embodiment.

[0041] In a further preferred embodiment of liquid composition 1 according to the present invention, the liquid composition comprises a further additive, preferably selected from the group consisting of a surface-active substance, an adhesion promoter, an additive that increases the conductivity, an organic binder, or a mixture of at least two of these further additives. This preferred embodiment is a fourth embodiment of liquid composition 1 according to the present invention, and is preferably dependent on any one of the first to third embodiments.

[0042] |1c| A contribution to solving at least one of the objects according to the present invention is a liquid composition 2 having a pH value in the range of 2.5 to 10, preferably in the range of 3 to 8, and comprising a functionalized π-conjugated polythiophene dissolved or dispersed in a solvent, wherein the polythiophene has the general formula (I): [ka] (In the formula, X and Y are the same or different and are O, S, or NR 1 and R 1 is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms, A is an organic residue having an anionic functional group, The composition obtained after drying Liquid Composition 2 at a temperature of 100°C and a pressure of 50 mbar for 16 hours was subjected to the following conditions (A) to (E): (A) a weight loss of 10 wt. % based on the total weight of the dried liquid composition at a temperature of 300° C. or greater, preferably 310° C. or greater, and even more preferably 320° C. or greater, as measured by thermogravimetric analysis; (B) a weight loss of 20 wt. % based on the total weight of the dried liquid composition at a temperature of 330° C. or greater, preferably 335° C. or greater, and even more preferably 340° C. or greater, as measured by thermogravimetric analysis; (C) a weight loss of 30 wt. % based on the total weight of the dried liquid composition at a temperature of 345°C or greater, preferably 350°C or greater, and even more preferably 355°C or greater, as measured by thermogravimetric analysis; (D) There is no peak in the differential plot between 250°C and 270°C. (E) The ratio of the derivative at 261°C to the derivative at the second peak is 0.1 or less, preferably 0.08 or less, and more preferably 0.07 or less, according to the first embodiment of liquid composition 2.

[0043] In this context, it is particularly preferred that the dried liquid composition 2 fulfills the following conditions or combinations of conditions: A, B, C, D, E, AB, AC, AD, AE, BC, BD, BE, CD, CE, DE, ABC, ABD, ABE, ACD, ACE, ADE, BCD, BCE, BDE, CDE, ABCD, ABCE, ABDE, ACDE, BCDE and ABCDE.

[0044] |2c| In a preferred embodiment of the liquid composition 2 according to the present invention, in the general formula (I), X and Y are O, A is -(CR 2 2) m -CR 2 R 3 -(CR 2 2) n - (In the formula, residue R 2 are, independently of each other, hydrogen or -(CH2) s -Z-(CR 4 2) p -SO3 - M + and R 3 is -(CH2) s -Z-(CR 4 ) p -SO3 - M + and Z is O, S or -CH2-; R 4 is hydrogen or an alkyl group, M + is a cation, m and n are the same or different and are integers of 0 to 3; s is an integer from 0 to 10, and p is an integer from 1 to 18.

[0045] This preferred embodiment is a second embodiment of the liquid composition 2 according to the invention and is preferably subordinate to the first embodiment.

[0046] |3c| In a further preferred embodiment of the liquid composition 2 according to the present invention, in the general formula (I), X and Y are O, A is -(CH2) s -CR 2 R 3 -(CH2) n - (In the formula, R 2 is hydrogen, R 3 is -(CH2)-O-(CH2) p -SO3 - M + and M + is an inorganic cation, preferably Na + or K + and n is 0 or 1, s is 0 or 1, p is 4 or 5).

[0047] This preferred embodiment is a third embodiment of the liquid composition 2 according to the invention and is preferably subordinate to the second embodiment.

[0048] |4c| In a further preferred embodiment of the liquid composition 2 according to the present invention, in the general formula (I), X and Y are O, A is -(CH2) s -CR 2 R 3 -(CH2) n - (In the formula, R 2 is hydrogen, R 3 is -(CH2) s -O-CH2-CH2-CHR 4 -SO3 - M + and M + is an inorganic cation, preferably Na + or K + and R 4 is CH3 or CH2CH3, preferably CH3, n is 0 or 1, s is 0 or 1, p is 4 or 5).

[0049] This preferred embodiment is the fourth embodiment of liquid composition 2 according to the invention and is preferably subordinate to the second embodiment.

[0050] |5c| In a further preferred embodiment of liquid composition 2 according to the present invention, the π-conjugated polythiophene is poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid) or a salt thereof, poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-2-butanesulfonic acid) or a salt thereof, or a mixture of these polymers. This preferred embodiment is a fifth embodiment of liquid composition 2 according to the present invention, and preferably depends on any one of the first to fourth embodiments.

[0051] |6c| In a further preferred embodiment of liquid composition 2 according to the present invention, the solvent is selected from the group consisting of water, aliphatic alcohols such as methanol, ethanol, isopropanol and butanol, diacetone alcohol, ethylene glycol and glycerol, aliphatic ketones such as acetone and methyl ethyl ketone, aliphatic nitrites such as acetonitrile, glycol ethers such as polyethylene glycol methyl ether, and mixtures of at least two of these solvents, in particular mixtures of water and water-miscible solvents, with water being the most preferred solvent. This preferred embodiment is a sixth embodiment of liquid composition 2 according to the present invention, and preferably depends on any one of the first to fifth embodiments.

[0052] In a further preferred embodiment of liquid composition 2 according to the present invention, the liquid composition comprises the functionalized π-conjugated polythiophene in an amount in the range of 0.1 to 25% by weight, preferably in the range of 0.25 to 10% by weight, and most preferably in the range of 0.5 to 4% by weight, in each case based on the total weight of liquid composition 2. This preferred embodiment is the seventh embodiment of liquid composition 2 according to the present invention, which preferably depends from any one of the first to sixth embodiments.

[0053] |8c| In a further preferred embodiment of the liquid composition 2 according to the present invention, the functionalized π-conjugated polythiophene is present in the form of particles, and the particle size distribution of these particles is i) a range of 1 to 100 nm, preferably a range of 1 to 80 nm, more preferably a range of 1 to 60 nm, and most preferably a range of 5 to 40 nm; 50 value (weight average particle size), and ii) 3.5 × d 50 Less than 3 × d 50 less than 2 × d 50 Less than d 90 It is characterized by value.

[0054] This preferred embodiment is an eighth embodiment of the liquid composition 2 according to the present invention, and preferably depends from any one of the first to seventh embodiments.

[0055] |9c| In a further preferred embodiment of the liquid composition 2 according to the present invention, the functionalized π-conjugated polythiophene in the liquid composition has a weight average molecular weight M of at least 6, preferably at least 8, more preferably at least 10, more preferably at least 12, more preferably at least 14, more preferably at least 16, more preferably at least 18, more preferably at least 20. w Molar average molecular weight M n Ratio to (M w / M n This preferred embodiment is a ninth embodiment of the liquid composition 2 according to the present invention, and preferably depends from any one of the first to eighth embodiments.

[0056] |10c| In a further preferred embodiment of the liquid composition 2 according to the present invention, the functionalized π-conjugated polythiophene in the liquid composition has a weight average molecular weight M of at least 50,000 g / mol, preferably at least 75,000 g / mol, more preferably at least 100,000 g / mol, and most preferably at least 125,000 g / mol. w This preferred embodiment is the tenth embodiment of liquid composition 2 according to the invention, and is preferably dependent on the ninth embodiment.

[0057] |11c| In a further preferred embodiment of the liquid composition 2 according to the present invention, the functionalized π-conjugated polythiophene in the liquid composition has a weight average molecular weight M in the range of 125,000 g / mol to 240,000 g / mol, preferably in the range of 125,000 g / mol to 210,000 g / mol. w This preferred embodiment is an eleventh embodiment of liquid composition 2 according to the invention, and is preferably dependent on the ninth or tenth embodiment.

[0058] |12c| In a further preferred embodiment of the liquid composition 2 according to the present invention, the functionalized π-conjugated polythiophene in the liquid composition has a molar average molecular weight M of less than 25000 g / mol, preferably less than 20000 g / mol, more preferably less than 15000 g / mol. n This preferred embodiment is a twelfth embodiment of liquid composition 2 according to the present invention, and preferably depends from any one of the ninth to eleventh embodiments.

[0059] In a further preferred embodiment of liquid composition 2 according to the present invention, a conductive layer produced by the liquid composition has a conductivity of more than 25 S / cm. This preferred embodiment is a thirteenth embodiment of liquid composition 2 according to the present invention, and is preferably dependent on any one of the first to twelfth embodiments.

[0060] In a further preferred embodiment of liquid composition 2 according to the present invention, the liquid composition comprises a further additive, preferably selected from the group consisting of a surface-active substance, an adhesion promoter, an additive that increases the conductivity, an organic binder, or a mixture of at least two of these further additives. This preferred embodiment is a 14th embodiment of liquid composition 2 according to the present invention, which is preferably dependent on any one of the 1st to 13th embodiments.

[0061] |1d| A contribution to solving at least one of the objects according to the invention is a method 2 for the preparation of a laminate, comprising: I) the method steps of providing a substrate; II) a method step of applying liquid composition 1 or liquid composition 2 according to the present invention, preferably liquid composition 1 according to any one of the first to fourth embodiments of liquid composition 1 or liquid composition 2 according to any one of the first to fourteenth embodiments of liquid composition 2, to at least a part of at least one surface of a substrate; III) optionally, the method step of at least partially removing the solvent to form a conductive layer covering at least a portion of at least one surface of the substrate.

[0062] In a preferred embodiment of the method 2 according to the invention, the substrate is an electrode body of an electrode material, and the dielectric at least partially covers one surface of this electrode material in the form of an anode body. This preferred embodiment is a second embodiment of the method 2 according to the invention, which is preferably dependent on the first embodiment.

[0063] |1e| A contribution to solving at least one of the objects according to the invention is also made by a laminate which can be obtained by the method 2 according to the invention, preferably by the method 2 according to the first or second embodiment.

[0064] |1f| A contribution to solving at least one of the objects according to the present invention is also made by the use of liquid composition 1 or liquid composition 2 according to the present invention, preferably liquid composition 1 according to any one of the first to fourth embodiments of liquid composition 1 or liquid composition 2 according to any one of the first to fourteenth embodiments of liquid composition 2, for the preparation of a conductive layer in an electronic device.

[0065] In a preferred embodiment of the use according to the present invention, the electronic device is selected from photoconductive cells, photoresistors, photoswitches, phototransistors, phototubes, IR detectors, photovoltaic devices, solar cells, coating materials for memory storage devices, field effect resistive devices, antistatic films, biosensors, electrochromic devices, electrolytic capacitors, energy storage devices, touch panels and electromagnetic shields. This preferred embodiment is a second embodiment of the use according to the present invention, which is preferably dependent on the first embodiment.

[0066] In a further preferred embodiment of the use according to the invention, the conductive layer is a solid electrolyte layer in a polymer electrolytic capacitor or a hybrid electrolytic capacitor. This preferred embodiment is a third embodiment of the use according to the invention, which is preferably dependent on the first or second embodiment.

[0067] Method 1 according to the present invention A contribution to solving these objectives is a method 1 for producing a liquid composition comprising a functionalized π-conjugated polythiophene, comprising: i) providing a liquid phase comprising a functionalized π-conjugated polythiophene dissolved or dispersed in a solvent, the functionalized π-conjugated polythiophene having the general formula (I): [ka] (In the formula, X and Y are the same or different and are O, S, or NR 1 and R 1 is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms, A is an organic residue having an anionic functional group, providing a liquid phase, the liquid phase having a pH value of less than 2.5, preferably less than 2.0; ii) adjusting the pH value of the liquid phase provided in process step i) to a value in the range of 2.5 to 10, preferably in the range of 3 to 8, by adding a base.

[0068] It has surprisingly been discovered that by adjusting the pH value of a liquid composition comprising a functionalized π-conjugated polythiophene (e.g., PEDOT-S) having a pH of less than 2.5 to a value in the range of 2.5 to 10 by the addition of a base, preferably an alkali metal hydroxide, a functionalized π-conjugated polythiophene characterized by significantly increased thermal stability is obtained.

[0069] In the functionalized π-conjugated polythiophene contained in the liquid phase prepared in process step i) (or contained in the liquid composition according to the invention), the repeating units of general formula (I) are represented by the following formula (I′): [ka] where an asterisk (*) indicates a bond to an adjacent repeat unit. Preferably, the functionalized π-conjugated polythiophene has positive charges along the polymer chain (not shown in formula (I')), and these positive charges are at least partially counterbalanced by anionic functional groups in the organic residue A.

[0070] In process step i) of method 1 according to the invention, a liquid phase is provided which comprises a functionalized π-conjugated polythiophene dissolved or dispersed in a solvent. Preferably, process step i) comprises: ia) a) General formula (I) [ka] wherein X, Y and A are defined as above; and b) an oxidizing agent; c) providing a liquid reaction mixture comprising: ib) a substep of oxidatively polymerizing the thiophene monomer of general formula (I) in the liquid reaction mixture obtained in process step ia) to obtain a liquid phase comprising a functionalized π-conjugated polythiophene; ic) optionally a sub-step of purifying the liquid phase obtained in process step ib), preferably by ionic filtration.

[0071] Among the preferred functionalized π-conjugated polythiophenes used in the methods and liquid compositions according to the present invention are poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid) or a salt thereof, and therefore, one preferred thiophene monomer a) is 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid. A further preferred functionalized π-conjugated polythiophene used in the methods and liquid compositions according to the present invention is poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-2-butanesulfonic acid) or a salt thereof, and therefore, a further preferred thiophene monomer a) is 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-2-butanesulfonic acid.

[0072] The oxidation reaction carried out in process step ib) can be catalyzed by a chemical oxidant, by electrochemical oxidation or by a combination of both methods. In the case of electrochemical oxidation, an electrode serves as the oxidant b).

[0073] Suitable oxidizing agents b) used as chemical oxidizing agents include salts of heavy metals, preferably iron salts, more preferably FeCl3, and iron(III) salts of aromatic and aliphatic sulfonic acids, HO, KCrO, peroxodisulfate salts, such as KSO, NaSO, KMnO, alkali metal perborates, and alkali metal or ammonium persulfates, or mixtures of these oxidizing substances. Heavy metal salts, peroxodisulfate salts, or mixtures thereof are particularly preferred. Further suitable oxidizing substances are described, for example, in Handbook of Conducting Polymers (Ed. Skotheim, TA), Marcel Dekker: New York, 1986, Vol. 1, pages 46-57. Particularly preferred oxidizing agents b) are peroxodisulfate salts, in particular K2S2O8, Na2S2O8, iron salts, in particular iron(III) chloride, or mixtures of peroxodisulfate salts with at least one further compound that catalyzes the cleavage of peroxodisulfate, for example mixtures of peroxodisulfate salts with iron salts. According to a particularly preferred embodiment of the process according to the invention, the oxidizing agent is a mixture of Fe2(SO4)3 and Na2S2O8.

[0074] Suitable solvents c) that can be used in the method 1 according to the present invention are those selected from the group consisting of water, water-miscible solvents, in particular aliphatic alcohols such as methanol, ethanol, isopropanol and butanol, diacetone alcohol, ethylene glycol and glycerol, aliphatic ketones such as acetone and methyl ethyl ketone, aliphatic nitrites such as acetonitrile, glycol ethers such as polyethylene glycol methyl ether, or mixtures of at least two of these solvents, in particular mixtures of water and water-miscible solvents. However, the most preferred solvent is water. Thus, in the case of 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid or 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-2-butanesulfonic acid as the thiophene monomer a), the method 1 according to the present invention allows the preparation of an aqueous solution containing a functionalized π-conjugated polythiophene.

[0075] The concentration of the thiophene monomer a) in the liquid reaction mixture provided in process step ia) is preferably in the range of 0.1 to 40% by weight, preferably in the range of 5 to 15% by weight.

[0076] There are various ways to prepare the liquid reaction mixture provided in process step ia). Thiophene monomer a) can be dissolved or dispersed in solvent c) followed by the addition of oxidizing agent b) (the oxidizing agent can also be dissolved or dispersed separately in the solvent), or oxidizing agent b) can be dissolved or dispersed first in solvent c) followed by the addition of thiophene monomer a) (the thiophene monomer can also be dissolved or dispersed separately in the solvent). When using two or more oxidizing agents, such as a mixture of Fe2(SO4)3 and Na2S2O8, it is further possible to first mix one of these components with thiophene monomer a) and solvent c) and then add the second oxidizing agent last.

[0077] Irrespective of the manner in which the liquid reaction mixture is prepared in process step ia), it is particularly preferred to reduce the oxygen content in the components used to prepare the liquid reaction mixture to such an extent that the oxygen content in the liquid reaction mixture is less than 1,000 ppm, more preferably less than 500 ppm, more preferably less than 100 ppm, more preferably less than 10 ppm, more preferably less than 1 ppm, more preferably less than 0.5 ppm, and most preferably less than 0.25 ppm, in each case based on the total weight of the liquid reaction mixture. According to a particularly preferred embodiment of process 1 according to the invention, the components used to prepare the liquid reaction mixture are completely free of oxygen (i.e. the oxygen content is 0 ppm).

[0078] Reduction of oxygen content can be achieved, for example, by stirring the components used to prepare the liquid reaction mixture under reduced pressure, by using ultrasound, or by degassing the components using an inert gas such as N, argon, CO or mixtures thereof, or by a combination of the above approaches.

[0079] The polymerization reaction in process step ib) is preferably carried out at a temperature in the range of from -20°C to 200°C, preferably in the range of from 0°C to 100°C, for a period of preferably from 1 to 48 hours, more preferably from 5 to 20 hours.

[0080] After the polymerization reaction is complete, the liquid phase comprising the functionalized π-conjugated polymer, preferably an aqueous solution comprising the functionalized π-conjugated polymer, can be further purified, for example by filtration, in particular by ultrafiltration, and / or by treatment with ion exchangers, in particular anion and cation exchangers, in a further process step ic). It is also possible to add further additives, as described below in connection with method 2 according to the invention.

[0081] Furthermore, since the functionalized π-conjugated polythiophene obtained after polymerization in process step ib) is usually present in the form of particles, the particle size distribution of the functionalized π-conjugated polythiophene in the liquid phase obtained in process step ib) or of the functionalized π-conjugated polythiophene in the liquid phase after further purification obtained in process step ic) can be adjusted by treating the liquid phase with ultrasound, with an energy input preferably of 10 to 1000 watts per liter (W / l), more preferably 20 to 500 W / l, and an ultrasound frequency preferably of 20 to 200 kHz; by treating the liquid phase with high-pressure homogenization, with a pressure of more than 100 bar, preferably more than 500 bar, and most preferably more than 1500 bar, preferably applied multiple times; or by treating the liquid phase with heat, which preferably comprises treating the liquid phase at a temperature in the range of 40 to 100° C., preferably in the range of 50 to 95° C., for a period of 5 minutes to 100 hours, preferably 1 to 10 hours, more preferably 2 to 8 hours.

[0082] Method 1 according to the invention is characterized in that the liquid phase provided in method step i) has a pH of less than 2.5. Such a pH can be obtained, for example, by adjusting the pH of the liquid reaction mixture provided in method ia) to a value less than 2.5, preferably less than 2.0, more preferably less than 1.5, the pH being measured at a temperature of 20°C.

[0083] Adjusting the pH to a value less than 2.5 is preferably achieved using an inorganic or organic acid, preferably a substantially chloride-free organic or inorganic acid. Suitable organic acids include carboxylic acids such as formic acid, acetic acid, lactic acid, propionic acid, citric acid, malic acid, fumaric acid, or mixtures thereof. Suitable inorganic acids are, in particular, sulfuric acid, sulfonic acid, nitric acid, phosphonic acid, phosphoric acid, or mixtures thereof. According to a particularly preferred embodiment of the method of the present invention, sulfuric acid is used to adjust the pH.

[0084] It is also advantageous according to particularly preferred embodiments of the process 1 according to the invention that the oxygen content of the liquid reaction mixture provided in process step ia) is less than 1,000 ppm, preferably less than 500 ppm, more preferably less than 100 ppm, more preferably less than 10 ppm, more preferably less than 1 ppm, more preferably less than 0.5 ppm and most preferably less than 0.25 ppm, in each case based on the total weight of the liquid reaction mixture. According to particularly preferred embodiments of the process 1 according to the invention, the oxygen content of the liquid reaction mixture provided in process step ia) is completely free of oxygen (i.e. the oxygen content is 0 ppm).

[0085] There are different approaches to adjusting the oxygen content in the liquid reaction mixture provided in process step ia) and to maintaining this low oxygen content during the polymerization reaction in process step ib).

[0086] According to one approach, the liquid reaction mixture provided in process step ia) (or the liquid components used to prepare the liquid reaction mixture) can be degassed by introducing an inert gas, such as N, argon, CO or mixtures thereof, into the liquid phase provided in process step ia) to reduce the initial oxygen content in the liquid phase. Alternatively, the liquid reaction mixture provided in process step ia) (or the liquid components used to prepare the liquid reaction mixture) can be subjected to a treatment with reduced pressure, or with ultrasound, or a combination of reduced pressure and ultrasound, in order to reduce the initial oxygen content, for example by stirring the liquid reaction mixture while applying a vacuum.

[0087] In order to ensure that a low oxygen content is maintained during the polymerization reaction in process step ib), it may be advantageous to carry out the polymerization reaction under an inert gas atmosphere, preferably under N, CO, argon or a mixture of at least two of these inert gases, and it may also be advantageous to carry out the oxidative polymerization in process step ib) under a pressure equal to or greater than the vapor pressure of the liquid reaction mixture during the polymerization reaction in process step ib). Preferably, the oxidative polymerization in process step ib) is carried out under a pressure that is at least 0.1 mbar, more preferably at least 0.5 mbar, and most preferably at least 1 mbar higher than the vapor pressure of the liquid reaction mixture during the polymerization reaction in process step ib). In order to ensure that a low oxygen content is maintained during the polymerization reaction in process step ib), it is also possible to carry out the oxidative polymerization in process step ib) under reduced pressure, preferably at a pressure of 0.8 bar or less, most preferably at a pressure of 0.5 bar or less.

[0088] In process step ii) of process 1 according to the invention, the pH value of the liquid phase provided in process step i) is adjusted to a value in the range from 2.5 to 10, preferably in the range from 3 to 8, by addition of a base, the pH again being measured at a temperature of 20°C.

[0089] In this context, it is particularly preferred that the base is an inorganic base, such as an alkali metal hydroxide or alkaline earth metal hydroxide, more preferably an inorganic base selected from the group consisting of ammonia, lithium hydroxide, lithium oxide, sodium hydroxide, sodium oxide, potassium hydroxide, potassium oxide, calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, barium hydroxide, barium oxide, lithium silicate, sodium silicate, potassium silicate, lithium borate, sodium borate, potassium borate, lithium carbonate, sodium carbonate, potassium carbonate, lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, trisodium phosphate and mixtures of at least two of these bases, with alkali metal hydroxides, in particular alkali metal hydroxides selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide and mixtures of at least two of these bases, being most preferred as bases for adjusting the pH in process step ii).

[0090] Method 2 according to the present invention A contribution to the achievement of the above-mentioned object also relates to a method 2 for the preparation of a laminate, comprising: I) the method steps of providing a substrate; II) a method step of applying liquid composition 1 or liquid composition 2 according to the present invention, preferably liquid composition 1 according to any one of the first to fifth embodiments of liquid composition 1 or liquid composition 2 according to any one of the first to fifteenth embodiments of liquid composition 2, to at least a part of at least one surface of a substrate; III) optionally, the method step of at least partially removing the solvent to form a conductive layer covering at least a portion of at least one surface of the substrate.

[0091] According to a particularly preferred embodiment of the method 2 according to the invention, the substrate is an electrode body of an electrode material, and the dielectric at least partially covers one surface of this electrode material in the form of an anode body. Thus, in such an embodiment, method step II) comprises: I) a method step of preparing an electrode body of an electrode material, wherein a dielectric material at least partially covers one surface of this electrode material under formation of an anode body; II) introducing liquid composition 1 or 2 according to the present invention, preferably liquid composition 1 according to any one of the first to fourth embodiments of liquid composition 1 or liquid composition 2 according to any one of the first to fourteenth embodiments of liquid composition 2, into at least a part of the electrode body.

[0092] In method step I), an electrode body of electrode material (a dielectric at least partially covers one surface of this electrode material to form the anode body) is first provided.

[0093] In principle, the electrode body can be produced by pressing a high-surface-area valve metal powder and sintering it to obtain a porous electrode body. Preferably, an electrical contact wire of a valve metal, such as tantalum, is also conventionally pressed into the electrode body. The electrode body is then coated with a dielectric, i.e., oxide layer, for example, by electrochemical oxidation. Alternatively, a metal foil can be etched and coated with a dielectric by electrochemical oxidation to obtain an anode foil with a porous region. In a wound capacitor, the anode foil and cathode foil with a porous region that form the electrode body are separated by a separator and wound together.

[0094] In the context of the present invention, valve metals should be understood to mean metals whose oxide layers do not allow current to flow equally in both directions. When a voltage is applied to the anode, the oxide layer of the valve metal blocks the current, while when a voltage is applied to the cathode, a large amount of current is generated, which may destroy the oxide layer. Valve metals include Be, Mg, Al, Ge, Si, Sn, Sb, Bi, Ti, Zr, Hf, V, Nb, Ta, and W, as well as alloys or compounds of at least one of these metals with other elements. The most well-known representative examples of valve metals are Al, Ta, and Nb. Compounds with electrical properties equivalent to valve metals have metallic conductivity, can be oxidized, and have oxide layers with the above-mentioned properties. For example, NbO has metallic conductivity, but is generally not considered a valve metal. However, since an oxidized NbO layer has typical properties of a valve metal oxide layer, NbO or alloys or compounds of NbO with other elements are typical examples of compounds with electrical properties equivalent to valve metals. Tantalum, aluminum electrode materials and electrode materials based on niobium or niobium oxide are preferred. Tantalum and aluminum are very particularly preferred as electrode materials.

[0095] To produce an electrode body, which often has porous regions, the valve metal can be sintered, for example, in powder form, to obtain a typically porous electrode body, or the porous structure can be imprinted onto the metal body, the latter being done, for example, by etching a foil.

[0096] For convenience, a body having a porous region will also be referred to as porous hereinafter. Thus, for example, an electrode body having a porous region will also be referred to as a porous electrode body. On the other hand, a porous body may have multiple channels extending throughout it and thus be sponge-like. This is often the case when tantalum is used to construct a capacitor. Furthermore, it is possible for only the surface to have pores, with the region below the surface pores being a solid structure. This situation is often observed when aluminum is used to construct a capacitor. Preferably, the electrode body is porous.

[0097] The electrode body thus produced, often porous, is then oxidized to form a dielectric by applying a voltage in a suitable electrolyte, such as, for example, aqueous phosphoric acid or ammonium adipate. The level of this formation voltage varies depending on the thickness of the oxide layer to be achieved or the subsequent operating voltage of the capacitor. Preferred formation voltages are in the range of 1 to 1000 V, particularly preferably in the range of 2 to 500 V, and very particularly preferably in the range of 1 to 300 V. According to a first specific embodiment of the method for producing a capacitor, the formation voltage is in the range of 1 to 20 V, and according to a second specific embodiment of the method for producing a capacitor, the formation voltage is in the range of 30 to 100 V.

[0098] The porous electrode bodies used as a rule preferably have a porosity of 10 to 90%, preferably 30 to 80%, particularly preferably 50 to 80% and an average pore diameter of 10 to 10,000 nm, preferably 20 to 5,000 nm, particularly preferably 50 to 3,000 nm.

[0099] According to a specific embodiment of Method 2 of the present invention, the electrolytic capacitor produced is an aluminum-wound capacitor. In this case, a porous aluminum foil is anodized as the electrode material, and an aluminum oxide coating is formed as the dielectric. The aluminum foil (anode foil) thus obtained is then provided with contact wires and wound with a further, optionally porous, aluminum foil (cathode foil) also provided with contact wires, and these two foils are separated from each other by one or more separators, for example, based on cellulose or preferably synthetic paper. After winding, the anode body thus obtained is fixed, for example, with adhesive tape. The separator can be carbonized by heating in an oven. The method and manner of producing the anode body for this aluminum-wound capacitor are well known in the prior art and are described, for example, in U.S. Pat. No. 7,497,879 (B2).

[0100] According to a further particular embodiment of method 2 according to the invention, the electrolytic capacitors produced are aluminum stack capacitors or tantalum electrolytic capacitors ("tantalum elco"), in particular tantalum electrolytic capacitors with a polymer outer layer such as those described in DE 10 2009 007 594 (A).

[0101] In method step II) of method 2 according to the present invention, liquid composition 1 or 2 according to the present invention is introduced into at least a portion of the anode body. In this connection, it should be noted that before introducing liquid composition 1 or 2 into at least a portion of the anode body, other compositions for forming an electrically conductive layer, such as a PEDOT / PSS dispersion, may be introduced into the anode body. Therefore, it is not necessarily necessary to apply liquid composition 1 or 2 directly to at least a portion of the dielectric layer of the anode body.

[0102] Liquid composition 1 or 2 is introduced into the porous region by known methods, such as impregnation, immersion, injection, dripping, spraying, atomizing, knife coating, brushing, or printing, such as inkjet, screen, or tampon printing. Preferably, the introduction is carried out by immersing the anode body in the liquid composition, thereby impregnating the anode body with the liquid composition. Immersion in or impregnation with the liquid composition is preferably carried out for a period ranging from 1 second to 120 minutes, particularly preferably from 5 seconds to 60 minutes, and most preferably from 10 seconds to 15 minutes. Introduction of the liquid composition into the anode body can be promoted, for example, by increasing or decreasing pressure, vibration, ultrasound, or heat.

[0103] The liquid composition 1 or 2 used in process step II) may contain, besides the remainder of the functionalized π-conjugated polymer a), the solvent c) and, optionally, the reduced form of the oxidizing agent b), further additives, such as surface-active substances, for example anionic surfactants, such as alkylbenzenesulfonic acids and salts, paraffin sulfonates, alcohol sulfonates, ether sulfonates, sulfosuccinates, phosphate esters, alkyl ether carboxylic acids or carboxylates, cationic surfactants, such as quaternary alkylammonium salts, nonionic surfactants, such as linear alcohol ethoxylates, oxoalcohol ethoxylates, alkylphenol ethoxylates or alkylpolyglucosides, in particular Dynol® and Zonyl®. (registered trademark), or adhesion promoters, such as organofunctional silanes or hydrolysates thereof, for example, 3-glycidoxypropyltrialkoxysilane, 3-amino-propyl-triethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane or octyltriethoxysilane, crosslinking agents, for example, melamine compounds, masked isocyanates, functional silanes (for example, tetraethoxysilane, alkoxysilane hydrolysates, for example, those based on tetraethoxysilane, epoxy silanes, for example, 3-glycidoxypropyltrialkoxysilane), polyurethane, polyacrylate or polyolefin dispersions.

[0104] Preferably, the liquid composition 1 or 2 used in process step II) comprises further additives which optionally increase the electrical conductivity, such as compounds containing an ether group, such as tetrahydrofuran, compounds containing a lactone group, such as γ-butyrolactone, γ-valerolactone, compounds containing an amide or lactam group, such as caprolactam, N-methylcaprolactam, N,N-dimethylacetamide, N-methylacetamide, N,N-dimethylformamide (DMF), N-methylformamide, N-methylformanilide, N-methyl Examples of suitable saccharides include pyrrolidone (N-methylpyrrolidone, NMP), N-octylpyrrolidone, pyrrolidone, etc.; sulfones and sulfoxides, such as sulfolane (tetramethylene sulfone), dimethylsulphoxide (DMSO), etc.; sugars or sugar derivatives, such as sucrose, glucose, fructose, lactose, etc.; sugar alcohols, such as sorbitol, mannitol, etc.; furan derivatives, such as 2-furancarboxylic acid, 3-furancarboxylic acid, etc.; glycerol, diglycerol, triglycerol, or tetraglycerol.

[0105] The liquid composition 1 or 2 used in process step II) may further comprise, as further additives, one or more organic binders that are soluble in organic solvents, as described in WO 2009 / 141209 A1, page 12, lines 16-34.

[0106] However, in this context it is particularly preferred that after the above-mentioned further additives have been added to the liquid composition, in process step ii) of process 1 according to the invention the pH value is adjusted to a value in the range from 2.5 to 10 by addition of a base.

[0107] The viscosity of the liquid composition 1 or 2 used in step II) of the method is 0.01 to 1,000 mPa×s (at 20°C and 100°C), depending on the application method. -1(measured with a rheometer at a shear rate of 100 Hz). Preferably, the viscosity is 1 to 500 mPa×s, particularly preferably 1 to 250 mPa×s. In the case of the production of aluminum wound capacitors, the viscosity is very particularly preferably in the range of 1 to 200 mPa×s, while in the case of the production of tantalum electrolytic capacitors or aluminum stacked capacitors, the viscosity is very particularly preferably in the range of 1 to 50 mPa×s. Viscosity adjustment can be achieved, for example, by adding suitable rheology modifiers as further additives.

[0108] The solids content of the liquid composition 1 or 2 used in process step II) is preferably in the range of 0.01 to 20% by weight, particularly preferably in the range of 0.1 to 15% by weight, and most preferably in the range of 0.25 to 10% by weight, based in each case on the total weight of the liquid composition. The solids content of the liquid composition is determined by drying the liquid composition at a temperature high enough to remove the solvent c).

[0109] According to a particularly preferred embodiment of method 2 according to the invention, liquid composition 1 or 2 introduced into the capacitor body not only comprises a functionalized π-conjugated polymer, but also (in addition to this self-doped conductive polymer) a hetero-doped conductive polymer, preferably PEDOT / PSS as disclosed in WO 2014 / 048562 A2. The disclosure of WO 2014 / 048562 A2 regarding the combined use of a self-doped polymer such as PEDOT-S with a hetero-doped polymer such as PEDOT / PSS for the formation of a solid electrolyte is incorporated herein by reference and forms part of the disclosure of the present application.

[0110] As mentioned above, after the anode body has been impregnated with the liquid composition 1 or 2 according to the invention, it is advantageous to at least partially remove the solvent c) contained in the liquid composition in a subsequent method step III) to form a solid electrolyte which completely or partially covers the dielectric and thus the capacitor body. In this connection, it is preferred that the coverage of the dielectric with the solid electrolyte is at least 10%, particularly preferably at least 25%, most preferably at least 50%, which coverage can be measured by measuring the capacitance of the capacitor in the dry and wet state at 120 Hz, as described in DE 10 2005 043 828 (A).

[0111] The removal or hardening is preferably carried out by removing the electrode body from the liquid composition and drying, preferably at temperatures in the range from 20°C to 260°C, particularly preferably in the range from 50°C to 220°C, most preferably in the range from 80°C to 200°C. Of course, it is also possible to at least partially remove the solvent c) by freeze-drying. Method steps II) and III) can also be repeated once or in this manner several times in succession in order to adapt the thickness of the layer of solid electrolyte deposited on the dielectric or the degree of filling of the electrolyte in the electrode body to specific requirements.

[0112] After the capacitor bodies are produced in this way, they can be further modified by methods and manners known to those skilled in the art. In the case of tantalum electrolytic capacitors, the capacitor body can be covered with a polymer outer layer, for example, as described in German Patent Application Publication No. 102004022674(A) or German Patent Application Publication No. 102009007594(A), and / or with a graphite layer and a silver layer as known from German Patent Application Publication No. 102005043828(A). In the case of aluminum-wound capacitors according to the teachings of U.S. Pat. No. 7,497,879(B2), the capacitor body is assembled into an aluminum beaker with a sealing glass and mechanically tightly closed by crimping. The capacitor can then be aged to eliminate defects in the dielectric in a known manner.

[0113] The invention will now be explained in more detail using non-limiting figures and examples. [Brief explanation of the drawings]

[0114] [Figure 1] 1 is a cross-sectional view of a portion of a capacitor obtainable by a method according to the invention for producing a capacitor. It has an electrode body 1, typically made of a porous electrode material 2, such as aluminum or tantalum. A thin layer of dielectric 3 is formed on the surface 4 of the electrode material 2, thereby forming a still porous anode body 5 comprising the electrode body 1 of the electrode material 2 and the dielectric 3. The dielectric 3 is optionally followed by further layers, and then by a layer 6 of a solid electrolyte (e.g., prepared using the liquid composition 1 or 2 according to the invention), thereby forming a capacitor body 7 comprising the electrode body 1 of the electrode material 2, the dielectric 3, and the solid electrolyte 6. [Figure 2] The top plot is a TGA plot showing weight loss versus temperature for samples #1-#7, and the bottom plot shows the derivative of the weight versus time scan. [Figure 3] The top plot is a TGA plot showing weight loss versus temperature for samples #4, #8, #9 and #10. The bottom plot shows the derivative of the weight versus time scan. [Figure 4] The top plot is a TGA plot showing weight loss versus temperature for samples #5, #11, #12 and #13. The bottom plot shows the derivative of the weight versus time scan.

[0115] Test Method Equivalent series resistance (ESR) The equivalent series resistance (unit: mΩ) was measured by an LCR meter (Agilent 4284A) at 20° C. and 100 kHz. For each capacitor experiment, at least five capacitors were prepared and the average ESR value was measured.

[0116] thermal stability Thermal stability is measured by thermogravimetric analysis (TGA).

[0117] TGA of solid samples is carried out using a Mettler Toledo TGA / DSC 2 LF / 1100. Approximately 10 g of the target polymer dispersion is dried in a beaker with a diameter of at least 3 cm in a vacuum oven at 50 mbar and 100°C for 16 hours to remove all solvent. Approximately 15 mg of solid conductive polymer is introduced into a measuring vial, which is then placed in the instrument's support.

[0118] First, the sample is heated from room temperature to 100°C. Then, the sample is held at 100°C for 30 minutes under N2 to dry the sample. Subsequently, the sample is heated in a second heating scan from 100°C to 600°C at a constant heating rate of 5 K / min without exposing the sample to air. The weight of the sample is monitored simultaneously while heating.

[0119] The weight loss of the sample monitored over time is converted into a plot of weight loss versus temperature. The data is normalized to 100 wt% at 100°C. The derivative of the data is then calculated by forming the ratio of the differential change in mass in wt% versus time.

[0120] conductivity A cleaned glass substrate was placed on a spin coater, and 10 mL of the liquid composition according to the present invention was distributed over the substrate. The remaining solution was then shaken off by rotating the plate. The thus-coated substrate was then dried on a hot plate at 130°C for 15 minutes. The layer thickness was then measured using a layer thickness measuring device (Tencor, Alphastep 500). The electrical conductivity was measured by depositing a 2.5 cm long Ag electrode at a distance of 10 mm through a shadow mask. To obtain the specific electrical resistivity, the surface resistance measured with an electrometer (Keithly 614) was multiplied by the layer thickness. The electrical conductivity is the reciprocal of the specific electrical resistivity.

[0121] average Unless otherwise stated, the average corresponds to the arithmetic mean value. [Example]

[0122] Example 1 (Preparation of PEDOT-S Dispersion) A stainless steel 3 L jacketed tank is equipped with a mechanical stirrer, a vent valve (on the top lid), a closable material inlet, and a thermometer.

[0123] Ingredient A 2000 g of deionized water, 16.0 g of 10 wt% aqueous iron (III) sulfate solution, 5.7 g of sulfuric acid (95 wt%), and 100 g of EDOT-S sodium salt (0.29 mol) were introduced into the tank. The stirrer was operated at 50 rpm, the temperature was adjusted to 20 °C, and the internal pressure was reduced to 100 hPa. The pressure in the tank was then increased to atmospheric pressure, and then further reduced to 25 hPa to expel oxygen.

[0124] Component B In a separate glass beaker, 78.5 g of sodium peroxodisulfate was dissolved in 200 mL of water, and nitrogen was bubbled through the solution with stirring for 30 minutes until the oxygen content was less than 0.25 mg / L.

[0125] Component B was then sucked into the tank. The material inlet was then closed, and the internal pressure of the tank was adjusted to 25 hPa using a vacuum pump. The initial pH of the reaction solution was 1.9, and the reaction continued under this reduced pressure for 19 hours. After the reaction was completed, the reaction mixture was filled up to a volume of 10 L by adding deionized water, and then treated by ultrafiltration (Pall Microza SLP 1053, cutoff 10,000 g / mol), thereby removing 8 L of water. This procedure was repeated six times to remove inorganic salts.

[0126] The composition thus obtained was characterized by a conductivity of 72 S / cm and a solids content of 1.22 wt. %. The composition was further concentrated by ultrafiltration until the solids content reached 2.4 wt. %. The PEDOT-S dispersion thus obtained is hereinafter referred to as "Sample #1."

[0127] Example 2 (pH adjustment with NaOH, Samples #2 to #7, #21 to #25) Approximately 50 mL of sample #1 is placed in a 100 mL beaker. A 10 wt% aqueous solution of NaOH is prepared and added dropwise to sample #1 while stirring until the solution reaches the desired pH. The pH of the solution is monitored with a pH meter (Model 766 Calimatic, Knick) as the base is added.

[0128] Example 3 (pH adjustment with LiOH, sample #8) Prepared as in Example 2, except that the pH was adjusted by adding 10 wt % LiOH aqueous solution.

[0129] Example 4 (pH adjustment with KOH, Samples #9 and #11) Prepared in the same manner as in Example 2, except that the pH was adjusted by adding 10 wt % aqueous KOH solution.

[0130] Example 5 (pH adjustment with NH4OH, Samples #10 and #12) Prepared as in Example 2, except that the pH was adjusted by adding 10 wt% aqueous NH4OH solution.

[0131] Example 6 (Adjusting pH with DMAH, Sample #13) Prepared in the same manner as in Example 2, except that the pH was adjusted by adding a 10% by weight aqueous solution of dimethylaminoethanol (DMAE).

[0132] The TGA diagrams for samples #1-#13 are outlined in Figures 2, 3, and 4, each showing weight loss versus temperature in the top diagram and the derivative of the weight versus time scan in the bottom diagram.

[0133] Table 1, in columns 5-8, lists the temperatures corresponding to 100%, 90%, 80%, and 70% sample weights extracted from the weight versus temperature data in Figures 2-4. The peak locations of the first peak at about 261°C and the second peak at about 345°C, where identifiable, are extracted from the derivative plots in Figures 2-4. [Table 1] 1) T1 = temperature at the first peak 2) DV1 = Differential value at 261°C 3) T2 = temperature at the second peak 4) DV2 = differential value at the second peak

[0134] Example 7 (Preparation of Capacitor) Tantalum powder with a specific capacity of 30,000 CV / g was pressed into a pellet together with a tantalum wire and sintered to form a porous anode body with dimensions of 1.4 mm × 2.8 mm × 3.9 mm. Five of these porous electrode bodies were anodized in a phosphoric acid electrolyte at 60 V to form a dielectric and obtain the anode body.

[0135] The anode body of sample #3 was immersed for 1 minute, and then dried at 120°C for 10 minutes.

[0136] The anode body was then immersed in a PEDOT:PSS dispersion (Clevios K Nano LV, Heraeus) for 1 minute, followed by drying at 120° C. for 10 minutes. The immersion and drying process was repeated nine more times.

[0137] The anode body was then immersed in a crosslinker solution (Clevios K Primer W5, Heraeus) and dried for 10 minutes at 120° C., and then immersed in a PEDOT:PSS dispersion (Clevios K V2 HV, Heraeus) and dried for 10 minutes at 120° C. This sequence of immersion in the crosslinker and PEDOT:PSS dispersion and drying was repeated two more times.

[0138] Finally, the anode body was covered with a graphite layer and then with a silver layer, thus obtaining a finished capacitor.

[0139] The average ESR was measured before and after the capacitors were exposed to 125°C for 100 hours. The relative increase in ESR was calculated as follows: Relative ESR Increase = [ESR (after exposure to 125°C) - ESR (before exposure to 125°C)] / ESR (before exposure to 125°C). The relative ESR increase values ​​(%) are shown in Table 2.

[0140] Example 8 A capacitor was prepared in the same manner as in Example 7, except that sample #4 was used instead of sample #3.

[0141] Example 9 A capacitor was prepared in the same manner as in Example 7, except that sample #5 was used instead of sample #3.

[0142] Example 10 A capacitor was prepared in the same manner as in Example 7, except that sample #6 was used instead of sample #3.

[0143] Example 11 A capacitor was prepared in the same manner as in Example 7, except that sample #8 was used instead of sample #3.

[0144] Example 12 A capacitor was prepared in the same manner as in Example 7, except that sample #11 was used instead of sample #3.

[0145] Example 13 A capacitor was prepared in the same manner as in Example 7, except that sample #12 was used instead of sample #4.

[0146] Example 14 A capacitor was prepared in the same manner as in Example 7, except that Sample #1 was used instead of Sample #3. [Table 2]

Claims

1. 1. A method for producing a liquid composition comprising a functionalized π-conjugated polythiophene, comprising: i) providing a liquid phase comprising a functionalized π-conjugated polythiophene dissolved or dispersed in a solvent, the functionalized π-conjugated polythiophene having the general formula (I): 【Chemistry 1】 (In the formula, X and Y are the same or different and are O, S, or NR １ and R １ is hydrogen or an aliphatic or aromatic residue having 1 to 18 carbon atoms, A is an organic residue having an anionic functional group, providing a liquid phase, the liquid phase having a pH value of less than 2.5; ii) adjusting the pH value of the liquid phase provided in process step i) to a value in the range of 2.5 to 10 by addition of a base.

2. said providing of said liquid phase in process step i) ia) a) General formula (I) 【Chemistry 2】 wherein X, Y and A are as defined in claim 1; and b) an oxidizing agent; and c) providing a liquid reaction mixture comprising a solvent; ib) a process step of oxidatively polymerizing said thiophene monomer of general formula (I) in said liquid reaction mixture obtained in process step ia) to obtain a liquid phase comprising a functionalized π-conjugated polythiophene; ic) optionally purifying the liquid phase obtained in process step ib), preferably by ionic filtration.

3. In general formula (I), X and Y are O; Aは、-(CR ２ ２ ) ｍ -CR ２ R ３ -(CR ２ ２ ) ｎ - (In the formula, residue R ２ are, independently of each other, hydrogen or -(CH ２ ) ｓ -Z-(CR ４ ２ ) ｐ -SO ３ － M ＋ and R ３ is -(CH ２ ) ｓ -Z-(CR ４ ) ｐ -SO ３ － M ＋ and Z is O, S or —CH ２ - and R ４ is hydrogen or an alkyl group, M ＋ is a cation, m and n are the same or different and are integers from 0 to 3; s is an integer from 0 to 10; The method according to claim 1 or 2, wherein p is an integer from 1 to 18.

4. In general formula (I), X and Y are O; A is -(CH ２ ) ｓ -CR ２ R ３ - (CH ２ ) ｎ - (In the formula, R ２ is hydrogen, R ３ is -(CH ２ )—O—(CH ２ ) ｐ -SO ３ － M ＋ and M ＋ is an inorganic cation, preferably Na ＋ or K ＋ and n is 0 or 1; s is 0 or 1; The method of claim 3, wherein p is 4 or 5.

5. In general formula (I), X and Y are O; A is -(CH ２ ) ｓ -CR ２ R ３ - (CH ２ ) ｎ - (In the formula, R ２ is hydrogen, R ３ is -(CH ２ ) ｓ -O-CH ２ -CH ２ -CHR ４ -SO ３ － M ＋ and M ＋ is an inorganic cation, preferably Na ＋ or K ＋ and R ４ is CH ３ or CH ２ CH ３ , preferably CH ３ and n is 0 or 1; s is 0 or 1; The method of claim 3, wherein p is 4 or 5.

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

7. The method according to any one of claims 1 to 6, wherein the base is an inorganic base.

8. 8. The method of claim 7, wherein the inorganic base is an alkali metal hydroxide.

9. A liquid composition comprising a functionalized π-conjugated polythiophene obtainable by the method according to any one of claims 1 to 8.

10. A liquid composition having a pH value in the range of 2.5 to 10 and comprising a functionalized π-conjugated polythiophene dissolved or dispersed in a solvent, said polythiophene having the general formula (I): 【Transformation 3】 wherein X, Y and A are as defined in claims 1 to 5, and the composition obtained after drying the liquid composition at a temperature of 100°C and a pressure of 50 mbar for 16 hours satisfies the following conditions (A) to (E): (A) a weight loss of 10 wt. % based on the total weight of the dried liquid composition at a temperature of 300° C. or greater, as measured by thermogravimetric analysis; (B) a weight loss of 20 wt. % based on the total weight of the dried liquid composition at a temperature of 330° C. or greater, as measured by thermogravimetric analysis; (C) a weight loss of 30 wt. % based on the total weight of the dried liquid composition at a temperature of 345°C or greater, as measured by thermogravimetric analysis; (D) There is no peak in the differential plot between 250°C and 270°C. (E) The ratio of the derivative at 261°C to the derivative at the second peak is 0.1 or less.

11. 1. A method for the preparation of a laminate, comprising: I) the method step of providing a substrate; II) a method step of applying a liquid composition according to claim 9 or 10 to at least a part of at least one surface of said substrate; III) optionally, the method step of at least partially removing said solvent to form a conductive layer covering at least a portion of at least one surface of said substrate.

12. 12. The method according to claim 11, wherein the substrate is an electrode body (1) of an electrode material (2), and a dielectric (3) at least partially covers one surface (4) of the electrode material (2) under the formation of an anode body (5).

13. 11. Use of the liquid composition according to claim 9 or 10 for the preparation of a conductive layer in an electronic device.

14. 14. The use according to claim 13, wherein the electronic device is selected from a photoconductive cell, a photoresistor, a photoswitch, a phototransistor, a phototube, an IR detector, a photovoltaic device, a solar cell, a coating material for a memory storage device, a field effect resistive device, an antistatic film, a biosensor, an electrochromic device, an electrolytic capacitor, an energy storage device, a touch panel and an electromagnetic shield.

15. 15. The use according to claim 13 or 14, wherein the conductive layer is a solid electrolyte layer in a polymer electrolytic capacitor or a hybrid electrolytic capacitor.

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