EP1614122A1

EP1614122A1 - Specific oxidation agents for producing conductive polymers

Info

Publication number: EP1614122A1
Application number: EP04722174A
Authority: EP
Inventors: Udo Merker; Stephan Kirchmeyer; Klaus Wussow
Original assignee: HC Starck GmbH
Current assignee: Heraeus Deutschland GmbH and Co KG
Priority date: 2003-04-02
Filing date: 2004-03-20
Publication date: 2006-01-11
Also published as: RU2005133623A; KR101174515B1; JP4538448B2; US20060180797A1; JP2006522182A; US7972534B2; RU2370838C2; KR20050117580A; RU2370838C9; MXPA05010361A; WO2004088672A1

Abstract

The invention relates to a method for producing specific oxidation agents, which, when mixed with precursors for the production of conductive polymers, exhibit a long processing time during the polymerisation process. The invention also relates to oxidation agents that are obtained by said method, to mixtures containing specific (retarding) oxidation agents of this type and to their use for producing solid electrolyte capacitors and conductive layers. The oxidation agents are produced by treating a metal salt of an organic acid or an inorganic acid comprising organic groups with an ion exchanger.

Description

Retarding oxidizing agents for the production of conductive polymers

The invention relates to a process for the production of special oxidizing agents which, in mixtures with precursors for the production of conductive polymers, have a high processing time during the polymerization, oxidizing agents obtainable by this process, mixtures containing such special (retarding) oxidizing agents and their use for the production of solid electrolytic capacitors and conductive layers.

The compound class of the ^ conjugated polymers has been the subject of numerous publications in the past decades. They are also called conductive polymers or synthetic. Referred to metals.

Conductive polymers are becoming increasingly important economically, as opposed to polymers

Metal advantages in terms of processability, weight and the targeted adjustment of

, Have properties through chemical modification. Examples of known 7τ-conjugated

Polymers are polypyrroles, polythiophenes, polyanilines, polyacetylenes, polyphenylenes and poly (p-phenylen-yinylenes). Layers of conductive polymers are used in a variety of technical ways. An overview of is in L. Groenendaal, F. Jonas, D. Freitag, H. Pielartzik & J. R. Reynolds, Adv. Mater. 12 (2000) 4SI - 494.

The production of conductive polymers takes place chemically oxidatively or electrochemically from precursors for the production of conductive polymers such as optionally substituted thiophenes, pyrroles and anilines and their respective optionally oligomeric derivatives. In particular, chemical oxidative polymerization is widespread because it is technically easy to implement on a variety of substrates. For this purpose, the precursors for the production of conductive polymers are polymerized using an oxidizing agent. The polymerization is so fast that ^{• the} precursors for the production of conductive polymers and the oxidizing agent usually have to be applied to the substrate one after the other. With this sequential application, however, the problem arises that stoichiometric relationships between the precursors for the production of conductive polymers and the oxidizing agent can be set only with great difficulty. As a result, the reaction to the polymer is incomplete, the precursors are used only incompletely, and the quality of the conductive layer and its conductivity are reduced.

In addition, the number of necessary process steps is multiplied by the sequential application, so that sequential processes are associated with significantly higher process costs. There is therefore a desire to use precursors for the production of conductive polymers and the oxidizing agent together and in precisely defined mixtures. Mixtures of oxidizing agents and precursors for the production of conductive polymers only have sufficiently low reaction rates at low temperatures to be able to be used in industrially usable processes. For example, in US 5 455 • 736 diluted mixture of pyrrole and oxidizing agent are cooled to low temperatures in order to slow down the polymerization sufficiently. On the one hand, the use of low temperatures is technically very complex, on the other hand, the solubility of the oxidizing agent is limited at low temperatures and the viscosity of the. Solution increases sharply with falling temperature. There is also the disadvantage that the low temperature causes moisture from the ambient air to enter the cooled solutions and the quality of the conductive polymers produced from these solutions is adversely affected.

EP-A 339 340 describes the chemically oxidative polymerization of 3,4-disubstituted thiophenes. With a suitable choice of the oxidizing agent, these thiophenes can also be processed into conductive layers in solution in the presence of the oxidizing agent. However, the reaction starts after a few minutes.

EP-A 615 256 describes that the addition of a non-volatile base such as imidazole can slow down the polymerization in mixtures of oxidizing agent and precursors for the production of conductive polymers. This allows the polymerization to be suppressed for a few hours. However, the additive remains in the conductive layer and can interfere with the function of the layer there. ^'

In US 6 001 281 the polymerization is slowed down by using two solvents with different boiling points. The more volatile solvent is chosen so that it weakly complexes the Fe (lJJ) used as the oxidizing agent and thus slows down the reaction. However, the solvent with the higher boiling point does not complex the Fe (IH). For the polymerization, the more volatile boiling agent is first evaporated, whereupon the reaction proceeds accelerated. This method has the major disadvantage that the reactive solution has to be diluted heavily with another solvent. Furthermore, the. solvents used such as tetrahydrofuran are not desired industrially.

There is therefore still a need for oxidizing agents which can be used together with precursors for the production of conductive polymers at temperatures which are technically easy to handle, the polymerization being suppressed for a sufficiently long time for industrial applications without having to carry out complex further process steps to prevent it. Therefore, the object was to find suitable oxidizing agent for the chemically oxidative polymerisation of precursors for producing conductive polymers and to produce, which suppress the polymerization sufficiently long and with which conductive ^layers' - can be prepared - for example, solid electrolyte capacitors, or other applications.

Another task was to find suitable oxidizing agents which are also stable in storage.

Surprisingly, it has now been found that oxidizing agents which have been produced by treating a metal salt of an organic acid or inorganic acid having organic residues with an ion exchanger meet these requirements.

The present invention therefore relates to a process for the production of an oxidizing agent for the production of conductive polymers, characterized in that a metal salt of an organic acid or inorganic acid having organic residues is treated with an ion exchanger.

In the invention, in general or within preferred ranges, radical definitions, parameters and explanations can set out below, with each other so there ^'combined between the respective ranges and preferred ranges in any way.

Inorganic or organic ion exchangers can be used as ion exchangers, but organic ion exchangers are preferred,

Inorganic anion exchangers are, for example, zeolites, montmorillonites, attapulgites, bentonites and other aluminosilicates, or else acid salts of polyvalent metal ions such as zirconium phosphate, titanium tungstate, nickel hexacyanoferrate (II).

Organic anion exchangers are, for example, polycondensates, e.g. from phenol and formaldehyde, or polymers, e.g. obtainable by copolymerization from styrene, acrylates or methacrylates and divinylbenzene, which were subsequently functionalized accordingly. However, other appropriately functionalized macromolecules, for example those of natural origin such as celluloses, dextrans and aragoses, can also be used.

The preceding enumeration serves as an example and is not to be interpreted as a limitation. The ion exchangers can be used in the use forms known to those skilled in the art, for example in the form of pearls, as granules, as powder resins, in ground form, incorporated into fabrics or fibers, as papers, layers or other bodies, in the form of ion exchange membranes, as liquid organic ion exchangers or optionally also used as a magnetic ion exchanger. The ion exchangers can be macroporous, microporous or gel-like. Macroporous ion exchangers are preferably used.

Anion exchangers are preferably used as ion exchangers. Anion exchangers have functional basic groups bonded to the ion exchanger, such as primary, secondary or tertiary amine groups or quaternary ammonium groups. Depending on the type and combination of the functional groups, the basicity of the ion exchangers can vary. For example, contain strongly basic ion exchangers usually quaternary ammonium groups, while weakly basic ^'ion exchangers often less basic primary, secondary and / or tertiary amine groups bear. However, any mixed forms are known between strong and weakly basic ion exchangers. Weakly basic anion exchangers are preferred in the sense of the invention. These can, for example, carry primary, secondary and / or tertiary amine groups, if appropriate together with quaternary ammonium groups. Such weakly basic ion exchangers with predominantly or exclusively tertiary amine groups as functional groups are particularly preferred.

Ion exchangers and their preparation are known to the person skilled in the art and are described in the relevant specialist literature, for example in Ullmann's Encyclopedia of Industrial Chemistry (Verlag Chemie, Weinheim), Volume 13, 4th Edition, pp. 281-308. However, all ion exchangers which can be prepared by newer methods and which have the properties listed above are also suitable for carrying out the process according to the invention.

Examples of suitable ion exchangers are like them, Leverkusen are sold functionalized with tertiary amines macroporous polymers of styrene and divinylbenzene, for example, under the trade name Lewatit ^® from Bayer AG.

The ion exchangers can be used in the process according to the invention without prior treatment. However, it is also possible to treat the ion exchangers with acids such as sulfuric acid or with bases such as sodium hydroxide or potassium hydroxide solution, for example in order to regenerate them before use. The ion exchangers used according to the invention can also be subjected to such a regeneration if their capacity has been exhausted to the extent that they are loaded to such an extent that they are not sufficiently interchangeable for the implementation of the method according to the invention. show more. In this way, ion exchangers can be recycled for use in the process according to the invention.

The metal salts are preferably treated with the ion exchanger in the presence of one or more solvents. Treatment can be continuous or discontinuous e.g. by mixing, stirring or shaking and subsequent separation, in a particular embodiment the treatment is carried out continuously. For this, e.g. a solution of the metal salt passed over a column containing the ion exchanger. Metal salt, solvents and ion exchangers can also be brought together in one container and stored there for a time of, for example, one minute to 72 hours. Then the ion exchanger can e.g. be separated from the oxidizing agent via a filter, a membrane or a centrifuge.

Depending on the solvent used and the temperature resistance of the ion exchanger used, the process according to the invention can be carried out at temperatures of, for example, -20 ° C. to 120 ° C. Preference is given to temperatures which permit simple and inexpensive industrial implementation, for example temperatures from 10 to 40 ° C., particularly preferably room temperature.

The amount of ion exchanger added depends on its capacity and the contact time of the metal salt and ion exchanger. If necessary, it can be determined by preliminary tests. The amount of ion exchanger is expediently chosen so that the resulting oxidizing agents according to the invention lead to a sufficiently low polymerization rate. Too small amounts of ion exchanger can lead to exhaustion of the ion exchanger before the metal salt has been adequately treated; too short a contact time can lead to incomplete treatment of the metal salt despite sufficient capacity of the ion exchanger. With too high capacities and or long contact times at the ion exchanger, an oxidizing agent can be produced which almost completely suppresses the polymerization at suitable process temperatures. The suitable amount of added ion exchanger can, if necessary, be determined by preliminary tests.

The ion exchangers used can be water-containing or water-free. In the context of the invention, in particular, water-containing means a water content of 1% by weight and more. In preferred embodiments, commercially available ion exchangers with a commercially available water content of, for example, 30 to 70% by weight are used. The water content of the ion exchanger can optionally be reduced before the treatment of the metal salt, for example by rinsing with a solvent or drying. This is particularly advantageous if a solution of an oxidizing agent with a low water content is desired. It has surprisingly been found that solutions of oxidizing agents according to the invention with a low water content are stable in storage under customary storage or transport conditions. Typical storage and transport conditions are understood to mean, for example, ambient pressure and ambient temperatures during transport and storage. In particular, the ambient temperatures can vary depending on the geographic location and the time of year and can usually be up to 30 ° C, for example. However, temperatures of up to 50 ° C or higher can also be reached.

In further preferred embodiments of the present invention, ion exchangers with such a low water content are therefore used that the solution of the oxidizing agent according to the invention after treatment with the ion exchanger has a water content of 0 to 10% by weight, preferably 0 to 5% by weight. %, particularly preferably from 0 to 2 wt .-%, each based on the total weight of the solution. For this purpose, the water content of ion exchangers with a high water content can be e.g. be reduced by gradually or continuously rinsing with an anhydrous solvent or by thermal drying or vacuum drying. The same solvent in which the oxidizing agent is dissolved is preferably used as the solvent for rinsing. However, other, for example less expensive, solvents can also be used. When using ion exchangers with a higher water content, the oxidants according to the invention can also be subsequently reduced in their water content after treatment with the ion exchanger, for example by drying and then dissolving them. an anhydrous solvent or by using dehydrating agents such as molecular sieves.

Such solutions of the oxidants according to the invention with a low water content have been found to be stable under normal storage and transport conditions, i.e. they show no precipitations for a period of up to several months. Solutions of oxidizing agents according to the invention with an increased water content, on the other hand, show, under the same conditions over time, i.e. under certain circumstances precipitations can occur after just a few hours or days. However, the latter solutions of oxidizing agents according to the invention can be cooled to temperatures of 10 ° C. or lower, preferably 6 ° C. or lower, in order to increase the storage stability.

The advantage of the solutions of the oxidants according to the invention with a low water content compared to solutions of the oxidants according to the invention with a higher water content is consequently that transport and / or storage do not require separate cooling. The solutions of the oxidizing agents according to the invention preferably contain 1 to 80% by weight, particularly preferably 10 to 60% by weight, very particularly preferably 15 to 50% by weight of the oxidizing agent according to the invention.

All metal salts known to the person skilled in the art and suitable for the oxidative polymerization of thiophenes, anilines or pyrroles as oxidizing agents can be used as metal salts.

Suitable metal salts are metal salts of main or subgroup metals, the latter also referred to below as transition metal salts, of the Periodic Table of the Elements according to Mendeleev. Transition metal salts are preferred. Suitable transition metal salts are in particular salts of an inorganic or organic acid or inorganic acid having organic residues of transition metals, such as iron (III), copper (IT), chromium (VI), cerium (), manganese () ₅ manganese ( VrJ), ruthenium (m) and zinc (II).

Preferred transition metal salts are those of iron (Jjr). Iron (IU) salts are often inexpensive, readily available and can be handled easily, such as the iron (IH) salts of inorganic acids, such as iron (II [) halide (eg FeCl ₃ ) or iron (IIt ) Salts of other inorganic acids, such as Fe (C10) ₃ or Fe ₂ (S0 ₄ ) ₃ , and the iron (TII) salts of organic acids and organic residues containing organic residues.

Examples of iron (IU) salts of organic residues containing inorganic acids are, for example, the iron (iπ) salts of the sulfuric acid semiesters of C 1 -C 20 -laols, e.g. called the iron (TIι) salt of lauryl sulfate.

Particularly preferred transition metal salts are those of an organic acid, in particular iron (ILT) salts of organic acids.

Examples of iron (JiI) ~ salts of organic acids which may be mentioned are: the iron (πi) salts of C 1 -C 2 -alkanesulfonic acids, such as methane, ethane, propane, butane or higher sulfonic acids such as dodecanesulfonic acid, of aliphatic perfluorosulfonic acids , such as trifluoromethanesulfonic acid, perfluorobutanesulfonic acid or perfluorooctanesulfonic acid, from aliphatic C; _[ -C20-Cafbonic acids such as 2-ethylhexylcarboxylic acid, of aliphatic perfluorocarboxylic acids such as trifluoroacetic acid or perfluorooctanoic acid, and of aromatic sulfonic acids optionally substituted by C 1 -C 2 -alkyl groups such as benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid or Dodecylbenzenesulfonic acid and cycloalkanesulfonic acids such as Ca phersulfonic acid. Any mixtures of these aforementioned iron (JJI) salts of organic acids can also be used.

The use of the iron (iπ) salts of organic acids and the inorganic acids containing organic residues has the great advantage that they do not have a corrosive effect.

Particularly preferred metal salts are iron (m) p-toluenesulfonate, iron (ITJ) -toluenesulfonate or a mixture of iron (πi) -p-toluenesulfonate and iron (lU) -o-toluenesulfonate.

Further suitable metal salts are peroxo compounds such as peroxodisulfates (persulfates), in particular ammonium and alkali peroxodisulfates, such as sodium and potassium peroxodisulfate, or alkali perborates and transition metal oxides, such as e.g. Manganese dioxide (manganese (IV) oxide) or cerium (IV) oxide.

The following are especially mentioned as solvents which are inert under the reaction conditions: aliphatic alcohols such as methanol, ethanol, i-propanol and butanol; aliphatic ketones such as acetone and methyl ethyl ketone; aliphatic carboxylic acid esters such as ethyl acetate and butyl acetate; aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane, heptane and cyclohexane; Chlorinated hydrocarbons such as dichloromethane and dichloroethane; aliphatic nitriles such as acetone-irile, aliphatic sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane; aliphatic carboxamides such as methylacetamide, dimefhylacetamide and dimethylformamide; aliphatic and araliphatic ethers such as diethyl ether and anisole. Furthermore, water or mixtures of water with the aforementioned organic solvents can also be used as the solvent. Solvents from the above-mentioned selection which enter into a reaction which is disadvantageous for the process according to the invention with the ion exchanger are only added after the treatment with the ion exchanger - either after the previous solvent has been removed beforehand or in addition to the latter.

One or more alcohol (s), water or a mixture of one or more alcohol (s) and water are preferably used as the solvent or solvents. Butanol, ethanol and methanol are particularly preferred among the alcohols.

The oxidizing agent produced according to the invention can be separated from the solvent after treatment with the ion exchanger and, if appropriate, can be dissolved again in the same or different solvent from the selection listed above.

The invention furthermore relates to oxidizing agents or solutions of oxidizing agents obtainable by the process according to the invention described above. All apply here Preferred ranges that apply to the process according to the invention, individually and in any combination, also for the oxidizing agents or their solutions obtainable by this process. The invention preferably relates to oxidizing agents or solutions of oxidizing agents prepared by the process according to the invention described above.

In comparison to oxidizing agents not treated with ion exchangers, the oxidizing agents according to the invention slow down or delay the polymerization - at the same concentration and the same reaction temperature - in reactive mixtures of precursors for the production of conductive polymers and oxidizing agents according to the invention. They are therefore also called retarding oxidizing agents in the following.

The reaction rate in the reactive mixtures and thus also the delaying or slowing effect can. moreover, if necessary, be further reduced by dilution and / or cooling.

Furthermore, more conductive layers can be produced from the oxidizing agents according to the invention than from oxidizing agents not treated with ion exchangers.

The retarding (retarding or slowing down) effect of the oxidizing agents according to the invention can be observed in a simple manner, for example, purely optically. To determine the retarding effect, it is possible, for example, to measure the time in which the first polymer particles are formed, which is visible to the eye. The time until visible formation of polymer particles in the reactive mixtures is preferably longer than one hour, particularly preferably longer than 10 hours and very particularly preferably longer than 20 hours.

The invention therefore relates to the use of the oxidizing agents obtainable by the process according to the invention as retarding oxidizing agents in the oxidative polymerization of precursors for the production of conductive polymers.

For the purposes of the invention, the term polymers encompasses all compounds with more than one. Repeating unit.

Conductive polymers are understood here to mean the class of compounds of 7r-conjugated polymers which have an electrical conductivity after oxidation or reduction. For the purposes of the invention, π-conjugated polymers are preferably understood to be conductive polymers which have electrical conductivity after oxidation. Examples include his optionally substituted polythiophenes, polypyrroles and polyanilines. Preferred conductive polymers for the purposes of the invention are optionally substituted polythiophenes, in particular optionally substituted poly (3,4-ethylenedioxythiophenes). Corresponding monomers or their derivatives are accordingly understood as precursors for the production of conductive polymers, hereinafter also referred to as precursors. Mixtures of different precursors can also be used. Suitable monomeric precursors are, for example, optionally substituted thiophenes, pyrroles or anilines, preferably optionally substituted thiophenes, particularly preferably optionally substituted 3,4-alkylenedioxythiophenes.

As the substituted 3,4-alkylenedioxythiophenes include the compounds of the general ^■ formula (I) called

wherein

A represents an optionally substituted C ₁ -C ₅ alkylene radical, preferably an optionally substituted C ₂ -C ₃ alkylene radical,

^• R is a linear or branched, optionally substituted Ci-Cis-alkyl radical, preferably linear or branched, optionally substituted Cι _Cι-4 alkyl, optionally substituted C ₅ -Cι ₂ cycloalkyl, optionally substituted C ₆ -C _I - Aryl radical, optionally substituted C ₇ -C ₈ aralkyl radical, optionally substituted C 1 -C ₄ hydroxyalkyl radical, preferably optionally substituted C ₁ -C ₂ hydroxyalkyl radical, or a hydroxyl radical, '

x represents an integer from 0 to 8, preferably from 0 to 6, particularly preferably 0 or 1,

in the event that a plurality of radicals R are bonded to A, these may be the same or different.

The general formula (I) is to be understood such that the substituent R can be bonded to the alkylene radical A x times.

Very particularly preferred monomeric precursors are optionally substituted 3,4-ethylenedioxythiophenes. Examples of substituted 3,4-ethylenedioxythiophenes are the compounds of the general formula (Ia)

wherein R and x have the meaning given for the general formula (I).

For the purposes of the invention, derivatives of these monomeric precursors are understood to mean, for example, dimers or trimers of these monomeric precursors. They are also higher molecular weight derivatives, i.e. Tetramers, pentamers etc. of the monomeric precursors are possible as derivatives.

Examples of derivatives of substituted 3,4-alkylenedioxythiophenes are the compounds of the general formula (H)

in which ■

n represents an integer from 2 to 20, preferably 2 to 6, particularly preferably 2 or 3,

U.N

A, R and x have the meaning given for the general formula (I).

The derivatives can be constructed from the same or different monomer units and can be used in pure form and in a mixture with one another and / or with the monomeric precursors. Oxidized or reduced forms of these precursors are also included in the sense of the invention by the term “precursors”, provided that the same conductive polymers are formed in their polymerization as in the precursors listed above.

The substituents mentioned for the general formula (I) for R are suitable as substituents for the precursors, in particular for the thiophenes, preferably for the 3,4-alkylenedioxythiophenes. In the context of the invention, C 1 -C ₅ -alkylene radicals A are methylene, ethylene, n-propylene, n-butylene or n-pentylene. C ₈ in the context of the invention represents linear or branched C ₈ alkyl radicals such as methyl, ethyl, n- or isopropyl, n-, iso-, sec- or tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, l, l-dimethylpropyl, ^' l, 2-dimethylpropyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, 2 -Ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl, C ₅ -Cι ₂ cycloalkyl for C ₅ -Ci ₂ cycloalkyl radicals such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclodecyl, C ₆ -C aryl for C ₆ -C ₄ aryl radicals such as phenyl, o-, m-, p-tolyl, 2,3-, 2,4 -, 2,5-, 2,6-, 3,4-, 3,5-xylyl, mesityl or naphthyl, and C ₇ -C ₈ aralkyl for C ₇ - C ₁₈ aralkyl radicals such as benzyl. The preceding list serves to explain the invention by way of example and is not to be regarded as conclusive.

Numerous organic groups come into consideration as possible substituents for the radicals R, for example alkyl, cycloalkyl, aryl, halogen, hydroxyl, ether, thiqether, disulfide, sulfoxide, sulfonic acid, sulfonate, amino , Aldehyde, keto, carboxylic acid ester, carbonate, carboxylate, cyano, alkylsilane and alkoxysilane groups and carboxylamide groups.

Processes for the preparation of the monomeric precursors for the production of conductive polymers and their derivatives are known to the person skilled in the art and are described, for example, in L. Groenendaal, F. Jonas, D. Freitag, H. Pielartzik & J. R. Reynolds, Adv. Mater. 12 (2000) 481-494 and the literature cited therein.

The advantage of applying the oxidizing agent and precursors together for the production of conductive polymers at technically easy-to-use temperatures is that the number of process steps is significantly reduced. In addition, a defined stoichiometric ratio between the reactants can be set in this way. For example, it is possible to convert the precursors into the polymer in high proportions, possibly even up to almost 100%.

Furthermore, the solutions or mixtures of the oxidizing agents and the precursors obtainable according to the invention are particularly suitable for producing conductive layers on the surface of porous or smooth substrates. Because the oxidizing agents and the precursors are uniformly distributed in the mixtures, the polymerization also produces homogeneous, ie dense - in the sense of non-porous or not very porous - polymer layers. In the case of sequential application of oxidizing agent and precursors, porous polymer layers arise due to local excess or deficit of oxidizing agent and precursors. The conductive layers obtainable from the mixtures according to the invention are therefore distinguished by a particular homogeneity and high conductivity. Furthermore, the solutions or mixtures according to the invention are accessible for processing for a significantly longer time than those which contain oxidizing agents which have not been treated with an ion exchanger. This makes it possible for the first time to use these mixtures or solutions in continuous, industrial manufacturing processes.

The invention also relates to mixtures comprising precursors for the production of conductive polymers and one or more oxidizing agents according to the invention and optionally one or more solvents, characterized in that the formation of polymers in the mixtures is delayed compared to untreated oxidizing agents.

The above-mentioned preferred ranges, definitions and examples for precursors, oxidizing agents and solvents according to the invention apply analogously here.

The mixtures according to the invention can be homogeneous or heterogeneous and single or multi-phase. The mixtures according to the invention are preferably solutions.

The oxidizing agents and precursors for the production of conductive polymers can be mixed together as a solid and / or liquid. However, one or more solvents are preferably added to the mixtures. Suitable solvents are above all the solvents already listed above. It is also possible to produce the mixtures directly on the surface to be coated, for example on an oxide layer of a metal or on a substrate surface. For this purpose, oxidizing agents and precursors for the production of conductive polymers are added in succession, preferably in the form of solutions, to the surface to be coated. The mixture is then created by mixing the individual components, i.e. Oxidizing agents and precursors, on the surface to be coated or, if appropriate, after partial or complete evaporation of the solvents by diffusion at the oxidizing agent interface to precursors.

The mixtures according to the invention can contain water. This water can, for example, originate from the oxidizing agent according to the invention or its solution and / or can be added subsequently to the mixtures according to the invention. The addition of water can increase the delay in the formation of polymers in the mixtures according to the invention, ie the pot life. Additional water is preferably added when using oxidizing agents according to the invention or their solutions with a low water content. 1 to 100% by weight, particularly preferably 1 to 60% by weight, very particularly preferably 1 to 40% by weight, of water, based on the weight of the oxidizing agent according to the invention, are preferably added. The conductive polymers produced with the oxidizing agents according to the invention can be neutral or cationic, but they are preferably cationic. Here, "cationic" refers only to the charges which are located on the main polymer chain. These positive charges must be saturated by counterions which, in the special embodiments in which the repeating units are substituted by anionic groups such as, for example, sulfonate or carboxylate groups The positive charges of the main polymer chain can be partially or completely saturated by the covalently bound anionic groups. In the event that there are more covalently bound anionic groups than positive charges, a negative total charge of the polymer can also result However, these are also considered cationic polymers in the context of the invention, since the positive charges on the polymer main chain

■ are decisive. The positive charges are generally not shown in formulas because their exact number and position cannot be determined correctly. The number of positive

However, charges are at least 1 and at most p, where p is the total number of all repetition units contained - identical or different - in the polymer.

To compensate for the positive charge, unless this is already done by optionally covalently bound sulfonate or carboxylate-substituted and thus negatively charged residues, the conductive polymers require anions as counterions.

Counterions can therefore be added to the mixtures. These can be monomeric or polymeric anions, the latter hereinafter referred to as polyanions.

The anions of polymeric carboxylic acids, such as polyacrylic acids, polymethacrylic acid or polymalefic acids, or the anions of polymeric sulfonic acids, such as polystyrene sulfonic acids and polyvinyl sulfonic acids, are preferably used as polyanions. These polycarbonic and sulfonic acids can also be copolymers of vinylcarbonic and vinylsulfonic acids with other polymerizable monomers, such as acrylic acid esters and styrene.

The anion of the polystyrene sulfonic acid is particularly preferred as the counter ion.

The molecular weight of the polyacids providing the polyanions is preferably 1,000 to 2,000,000, particularly preferably 2,000 to 500,000. The polyacids or their alkali metal salts are commercially available, for example polystyrene sulfonic acids and polyacrylic acids, or else can be prepared by known processes (see, for example, Houben Weyl , Methods of Organic Chemistry, Vol. E 20 Macromolecular Substances, Part 2, (1987), p. 1141 u.fi). The monomeric anions such as those used by Cι-C20 alkane sulfonic acids, such as methane, ethane, propane, butane or higher sulfonic acids such as dodecane, of aliphatic perfluorosulfonic acids, such as trifluoromethanesulfonic acid, perfluorobutane sulfonic ^■ or perfluorooctane sulfonic acid, of aliphatic Ci -C20 carboxylic acids such as 2-ethylhexyl carboxylic acid, of aliphatic perfluorocarboxylic acids such as trifluoroacetic acid or perfluoro-octanoic acid, and of aromatic sulfonic acids optionally substituted by Cτ -C20 alkyl groups such as benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid or dodecylbenzenesulfonic acid and cycloalkanesulfonic acids such as camphorsulfonic acid or tetrafluoroborate, hexafluorophosphate, perchlorate, hexafluoroantimonate, hexafluoroarsenate or hexachloroantimonate.

The anions of p-toluenesulfonic acid, methanesulfonic acid or camphorsulfonic acid are preferred. ^•

The counterions are added to the mixtures, for example in the form of their alkali salts or as free acids.

The anions present in the oxidizing agent used preferably serve as counterions, so that the addition of additional counterions is not absolutely necessary.

The mixtures according to the invention can also contain other components such as one or more organic binders which are soluble in organic solvents, such as polyvinyl acetate, polycarbonate, polyvinyl butyrate, polyacrylic acid esters, polymethacrylic acid esters, polystyrene, polyacrylonitrile, polyvinyl chloride, polybutadiene, polyisoprene, polyethers, polyesters, silicones, pyrrole / Acrylic acid ester, vinyl acetate / acrylic acid ester and ethylene / vinyl acetate copolymers or water-soluble binders such as polyvinyl alcohols, crosslinking agents such as polyurethanes or polyurethane dispersions, polyacrylates, polyolefin dispersions, epoxysilanes such as 3-glycidoxypropyltrialkoxysilane, and additives such as, for example surfactants are added. Furthermore, alkoxysilane hydrolysates e.g. based on tetraethoxysilane to increase the scratch resistance of coatings.

For the oxidative polymerization of the precursors for the production of conductive polymers, 2.25 equivalents of oxidizing agents are theoretically required per mole of thiophene (see, for example, J. Polym. Sc. Part A Polymer Chemistry Vol. 26, p. 1287 (1988)). However, lower or higher equivalents of oxidizing agent can also be used. The mixtures preferably contain 1 to 30% by weight of the precursors for the production of conductive polymers and 0 to 50% by weight of binders, crosslinking agents and / or additives, both weight percentages based on the total weight of the mixture.

The polymerization rate in mixtures containing precursors for the production of conductive polymers and at least one oxidizing agent is determined in addition to the concentration of the starting materials by the reaction constants of the polymerization. The reaction constants k have a temperature dependency, which is given by:

k = υ * e -EaIRT

where v is the frequency factor, E _{a is} the activation energy in J / mol, R is the gas constant 8.3145 JK'mol ^"1 and T is the temperature in Kelvin.

The activation energy is a temperature and concentration independent parameter for the reaction rate. A high activation energy leads to slower reactions and thus longer pot lives of the mixtures.

The present invention furthermore relates to mixtures comprising precursors for the production of conductive polymers and at least one oxidizing agent, characterized in that the polymerization of the precursors has an activation energy of 75 kJ / mol or greater, preferably 85 kJ / mol or greater, particularly preferably 95 kJ / has mol or greater. Activation energies that are too high can have the disadvantage that the polymerization only starts at very high temperatures, which is disadvantageous for the production of conductive polymers. The activation energy is therefore preferably less than 200 kJ / mol, particularly preferably less than 150 kJ / mol and very particularly preferably less than 130 kJ / mol.

To. To determine the activation energy, it is necessary to experimentally determine the concentration profile of starting materials (precursors, oxidizing agents) and products. If a model that describes the kinetics of the individual reaction sub-steps is adapted to the concentration curve at different reaction temperatures, the reaction constants are obtained for different temperatures. The activation energy of the reaction can then be determined from the temperature dependence of the reaction constant k using the above formula.

The determination of activation energies and the implementation of the kinetic measurements are known to the person skilled in the art and are, for example, in "Kinetics of homogeneous multistep reactions" by FG Helfferich, published by RG Compton and G. Hancock as volume 38 in the series "Comprehensive Chemical Kinetices", ( Elsevier, Amsterdam 2001). Example 11 describes how the activation energies of the polymerization in , Mixtures containing 3,4-ethylenediόxythioρhen as precursors and iron (JH) -ρ-toluenesulfonate as oxidizing agent were determined.

The mixtures according to the invention can furthermore contain solvents, counterions, binders and / or crosslinking agents.

The above-mentioned preferred ranges, definitions and examples for precursors, counterions, binders, crosslinking agents and solvents apply analogously here.

A metal salt of an organic acid or inorganic acid having organic radicals is preferably suitable as the oxidizing agent.

All such metal salts known for the oxidative polymerization of thiophenes, anilines or pyrroles as suitable oxidizing agents can be used as such metal salts. ^•

Suitable metal salts are metal salts of main or subgroup metals, the latter also referred to below as transition metal salts, of the Periodic Table of the Elements according to Mendeleev. Transition metal salts are preferred. Suitable transition metal salts are in particular salts of an inorganic or organic acid or inorganic acid having organic residues of transition metals, such as iron (JJI), copper (H), chromium (VI), ^' . Cerium (IV), Manganese (IV), Manganese (VJI), Rumeniurn (III) and Zinc (7J).

Preferred transition metal salts are those of iron (IH). Iron (m) salts are often inexpensive, readily available and easy to handle, such as the iron (πT salts of inorganic acids, such as iron (iπ) halogenide (eg FeCl ₃ ) or iron (IH) salts of others inorganic acids, such as Fe (C10 ₄ ) ₃ or Fe ₂ (S0 ₄ ) ₃ , and the iron (IH) salts of organic acids and inorganic acids containing organic residues.

As iron (πi) salts containing organic residues of inorganic acids, for example the iron (IH) salts of the sulfuric acid semiesters of C 1 -C 2 -alkanols, for example the iron (IH) salt of ^" lauryl sulfate.

Particularly preferred transition metal salts are those of an organic acid, in particular iron (in) salts of organic acids.

Examples of iron (TlI) salts of organic acids are: the iron (LTt) salts of

Cι -C2o alkane sulfonic acids, such as methane, ethane, propane, butane or higher sulfonic acids such as dodecane sulfonic acid, of aliphatic perfluorosulfonic acids, such as trifluoromethane sulfonic acid, perfluorobutane sulfonic acid or perfiuorooctane sulfonic acid, of aliphatic C -C20 carboxylic acids such as 2-ethylhexylcarboxylic acid, of aliphatic perfluorocarboxylic acids such as trifluoroacetic acid or perfluorooctanoic acid, and of aromatic sulfonic acids optionally substituted by C20 -C20 alkyl groups such as benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid or Dodecylbenzenesulfonic acid and cycloalkanesulfonic acids such as camphorsulfonic acid.

Any mixtures of these aforementioned iron (ITJ) salts of organic acids can also be used.

The use of the iron (ITI) salts of organic acids and the inorganic acids containing organic residues has the great advantage that they are not corrosive.

Iron (ILt) -p-toluenesulfonate, iron (iπ) -o-toluenesulfonate or a mixture of iron (πi) -p-toluenesulfonate and iron (rfi) -o-toluenesulfonate are very particularly preferred as metal salts. ,

In preferred embodiments, the mixtures according to the invention contain an oxidizing agent obtainable according to the method according to the invention described above.

In further preferred embodiments, the mixtures according to the invention contain optionally substituted thiophenes, pyrroles, anilines or their derivatives as precursors for the preparation of conductive polymers. Optionally substituted 3,4-ethylenedioxythiophenes or their derivatives are particularly preferred, very particularly preferably 3,4-ethylenedioxythiophene.

In further preferred embodiments, the mixtures according to the invention contain as. Oxidizing agent is an iron (III) salt, preferably iron (IJJ) -p-toluenesulfonate, iron (πT) -o-toluenesulfonate or a mixture of iron (ITI) -p-toluenesulfonate and iron (rJT) -o-toluenesulfonate ,

In further preferred embodiments, water, preferably 1 to 100% by weight, particularly preferably 1 to 60% by weight, very particularly preferably 1 to 40% by weight of water, based on the weight of the oxidizing agent, is added to the mixtures according to the invention ,

The mixtures according to the invention can also be formed in situ by, for example, dipping sequentially in an oxidizing agent, optionally in the form of a solution, and precursors, optionally in the form of a solution, depending on the particular surface

Dipping process can optionally be followed by drying. The mixtures then arise for example by interfacial diffusion or by mixing different liquids on the surface. These mixtures are also to be regarded as mixtures according to the invention within the scope of the invention.

The mixtures according to the invention can be used to produce electrolytic capacitors. In principle, an electrolytic capacitor is produced by first oxidatively oxidizing a metal, for example by electrochemical oxidation, with a dielectric, ie. H. an oxide layer is coated. A conductive polymer which forms the solid electrolyte is then chemically deposited on the dielectric by means of oxidative polymerization, according to the invention using one of the mixtures described above. A coating with other highly conductive layers, such as graphite and silver, serves to dissipate the current. Finally, the capacitor body is coactivated and encapsulated.

In the process according to the invention, the “oxidizable metal” preferably forms an anode body with a large surface, for example in the form of a porous sintered body or a roughened foil. In the following, this is also referred to briefly as an anode body.

According to the invention, the solid electrolyte made of conductive polymer is produced on the anode body covered with an oxide layer by oxidative polymerization of the mixtures described above, by applying these mixtures, preferably in the form of solutions, to the oxide layer of the anode body and the oxidative polymerization, depending on the activity of the one used Oxidizing agent, optionally by heating the coating to the end.

The present invention therefore also relates to a process for producing an electrolytic capacitor, characterized in that the mixtures according to the invention are applied, if appropriate in the form of solutions, to an oxide layer of a metal and are chemically oxidative at temperatures from -10 ° C. to 250 ° C. to the corresponding ones Polymers are polymerized.

The present invention furthermore relates to a process for producing an electrolytic capacitor, characterized in that precursors for the production of conductive polymers and the oxidizing agents obtainable according to the invention are applied in succession, optionally in the form of solutions, to an oxide layer of a metal and chemically oxidatively at temperatures of -10 ° C to 250 ° C to be polymerized to the corresponding polymers. The application can be carried out directly or using an adhesion promoter, for example a silane, and / or another functional layer on the oxide layer of the anode body.

Depending on the oxidizing agent used and the desired reaction time, the oxidative chemical polymerization of the precursors for the production of conductive polymers is generally carried out at temperatures from -10 ° C. to 250 ° C., preferably at temperatures from 0 ° C. to 200 ° C.

Like the mixtures according to the invention, counterions can also be added to the solutions. Suitable counterions are those listed above for the mixtures according to the invention.

The anions of the monomeric alkane or cycloalkane sulfonic acids or aromatic sulfonic acids are particularly preferred for use in the electrolytic capacitors according to the invention, since solutions containing them are more suitable for penetrating into the porous anode material and thus a larger contact area can be formed between the anode material and the solid electrolyte.

In addition, the anions of the oxidizing agent used, which may be present, can preferably serve as counterions for use in the electrolytic capacitors according to the invention, so that addition of additional counterions is not absolutely necessary.

Like the mixtures according to the invention, the solutions can additionally contain one or more binders, crosslinking agents and / or additives. Suitable binders, crosslinking agents and / or additives are those listed above for the mixtures according to the invention.

Those already listed above are suitable as precursors for the production of conductive polymers.

The mixtures according to the invention are produced by known processes, e.g. applied to the oxide layer of the anode body by impregnation, pouring, dripping, spraying, spraying, knife coating, brushing or printing.

The solvent, if used, can be removed after the mixtures have been applied by simple evaporation at room temperature. To achieve higher processing speeds, however, it is more advantageous to remove the solvents at elevated temperatures, for example at temperatures from 20 to 300 ° C., preferably 40 to 250 ° C. A thermal aftertreatment can be carried out immediately with the removal of the solution medium connected or can also be carried out at an interval from the completion of the coating.

The duration of the heat treatment is 5 seconds to several hours, depending on the type of polymer used for the coating. Temperature profiles with different temperatures and residence times can also be used for the thermal treatment.

The heat treatment can e.g. in such a way that the coated anode bodies are moved at such a speed through a heating chamber at the desired temperature so that the desired residence time is achieved at the selected temperature, or with a heating plate at the desired temperature for the desired residence time brings in contact. Furthermore, the heat treatment can be carried out, for example, in one or more heating ovens. different temperatures take place.

After the removal of the solvents (drying) and optionally after the thermal aftertreatment, it may be advantageous to wash out the excess oxidizing agent and residual salts from the coating with a suitable solvent, preferably water or alcohols. Residual salts are to be understood here as the salts of the reduced form of the oxidizing agent and, if appropriate, other salts present.

Depending on the type of anode body, it can be advantageous to impregnate the anode body with the mixtures a further number of times, preferably after washing, in order to achieve thicker polymer layers.

After the polymerization and preferably during or after washing, it can be advantageous to electrochemically simulate the oxide film in order to repair any defects in the oxide film and thereby reduce the residual current in the finished capacitor (reforming).

Furthermore, a method is preferably characterized in that the oxidizable metal is a valve metal or a compound with comparable properties.

Within the scope of the invention, valve metal is to be understood as those metals whose oxide layers do not allow the current to flow in both directions equally: With an anodically applied voltage, the oxide layers of the valve metals block the current flow, while with cathodically applied voltage large currents occur which destroy the oxide layer can. The valve metals include Be, Mg, Al, Ge, Si, Sn, Sb, Bi, Ti, Zr, Hf, V, Nb, Ta and W and an alloy or combination of at least one of these metals with other elements. The best known representatives of valve metals are AI, Ta and Nb. Connections with comparable Properties are those with metallic conductivity, which can be oxidized and whose oxide layers have the properties described above. For example, NbO has metallic conductivity, but is generally not considered a valve metal. However, layers of oxidized NbO have the typical properties of valve metal oxide layers, so that NbO or an alloy or compound of NbO with other elements are typical examples of such compounds with comparable properties.

Accordingly, the term “oxidizable metal” means not only metals but also an alloy or compound of a metal with other elements, provided that they have metallic conductivity and are oxidizable.

Accordingly, the present invention particularly preferably relates to a method, characterized in that the valve metal or the compound ^' with comparable properties is tantalum, niobium, aluminum, titanium, zirconium, hafnium, vanadium, an alloy or compound of at least one of these Metals with other elements, NbO or an alloy or compound of NbO with other elements.

In the process according to the invention, the “oxidizable metal” preferably forms an anode body with a large surface, for example in the form of a porous sintered body or a roughened foil.

However, the method according to the invention is not only suitable for the production of electrolytic capacitors, but also for the production of conductive layers for other applications.

According to the invention, the layers are produced by a process which delivers the conductive layers by oxidative polymerization of the mixtures according to the invention.

The present invention therefore also relates to a process for the production of electrically conductive layers, characterized in that the mixtures according to the invention, preferably in the form of solutions, are applied to a base and chemically conductive polymers on this base at temperatures of from -10 ° C. to 250 ° C, preferably at temperatures from 0 ° C to 200 ° C, polymerized.

The present invention furthermore also relates to a process for the production of conductive layers, characterized in that precursors for the production of conductive polymers and oxidizing agents obtainable according to the invention are applied in succession, optionally in the form of solutions, to a base and chemically oxidatively on this base at temperatures of - 10 ° C to 250 ° C to be polymerized to the corresponding conductive polymers. Exemplary and preferred reaction conditions, molar ratios, percentages by weight, solvents, oxidizing agents, precursors for the production of conductive polymers and the variants or particularities described in connection with these in carrying out the oxidative polymerization correspond to those already described above for the production of the electrolytic capacitors.

For flat substrates, in addition to the application methods described for capacitors, spin-coating of the mixtures or solutions is particularly suitable (spin coating).

Like the mixtures according to the invention, counterions can also be added to the solutions. Suitable counterions are those listed above for the mixtures according to the invention, wherein the polyanions can lead to improved film formation properties for the formation of polymer films and are therefore preferred.

The electrically conductive layers produced according to the invention can be washed with suitable solvents after the polymerization and, if appropriate, after drying, as described for the electrolytic capacitors, in order to prevent excess oxidation. remove medium and residual salts.

The base can be, for example, glass, vapor glass (flexible glass) or plastics.

Particularly suitable plastics are: polycarbonates, polyesters such as e.g. PET and PEN (polyethylene terephthalate or polyethylene naphthenate), copolycarbonates, polysulfone, polyether sulfone, polyimide, polyethylene, polypropylene or cyclic polyolefins or cyclic olefin copolymers (COC), hydrogenated styrene polymers or hydrogenated styrene copolymers.

Suitable polymer substrates can be, for example, films such as polyester films, PES films from Surnitomo or polycarbonate films from Bayer AG (Makrofol®).

The conductive layers produced according to the invention can remain on the base or be detached from it.

Depending on the application, the polythiophene layers have a thickness of 1 nm to 100 μm, preferably 10 nm to 10 μm, particularly preferably 50 nm to 1 μm. The layers produced according to the invention are outstandingly suitable for use as an antistatic coating, as transparent heating, as optionally transparent electrodes, as hole-injecting or hole-conducting layers in organic light-emitting diodes, for through-contacting printed circuit boards or as solid electrolyte in electrolytic capacitors. They can advantageously be transparent.

As antistatic coatings, they can be used, for example, on films, packaging of electronic components, for finishing plastic films and for screen coating. Furthermore, they can be used as cathode materials in capacitors, as transparent electrodes, for example in displays, for example as a replacement for jxidium tin oxide electrodes, or as electrical conductors in polymer electronics. Other applications include sensors, batteries, solar cells, electrochromic windows (smart windows) and ^'displays and the corrosion protection.

The present invention furthermore relates to the use of the oxidizing agents according to the invention or produced by the method according to the invention and of the mixtures according to the invention for the production of conductive layers and electrolytic capacitors.

The examples listed below should not be interpreted as a limitation.

Examples

Example 1:

a) Preparation of a solution of an oxidizing agent according to the invention

In a volume measuring vessel two volume parts of a 40 wt .-% solution of iron (ιJJ) were separately -p-toluenesulfonate in ethanol and one part by volume of the weakly basic, macroporous anion exchanger Lewatit MP 62 ^® (Bayer AG) were measured. The solid anion exchanger was dimensioned using a simple bed (the volume parts of the solid anion exchanger in the following examples were also measured in this way). The measured volumes of ethanolic solution of iron (iπ) -p-toluenesulfonate and of anion exchanger were then mixed in a closed container for 24 hours with a shaker. The anion exchanger was then filtered off.

b) Preparation of a mixture of oxidizing agent and precursors according to the invention

1 part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of the solution prepared as described under a) of the oxidizing agent according to the invention were mixed with stirring and the resulting mixture in a refrigerator at about 6 ° C storage. At regular intervals, a thin solution film of the mixture according to the invention was shined through with a lamp and examined for solid particles by eye. The time between the preparation of the mixture and the time at which the first particles became visible was defined as the pot life.

The pot life was 24 hours.

Example 2:

Of a 40 wt .-% solution of iron (ILT) -p-toluenesulfonate in ethanol analogously to Example 1, various amounts were added to anion exchangers and then determines the ^"pot life in mixtures with 3,4-Ethγlendioxythiophen.

a) Preparation of solutions of oxidizing agents according to the invention

Thereto was added a 40 wt .-% ethanolic solution of iron (LT [) - p-toluenesulfonate in the volume ratio 9: 3 1: 1 and 2: 1 with the weakly basic anion exchanger Lewatit macroporous ^® MP 62 (Bayer AG), respectively mixed with a shaker for 7 hours, and then the anion exchanger was filtered off. b) Preparation of mixtures according to the invention from oxidizing agent and precursors

A mixture was prepared consisting of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of the solutions of the oxidizing agents of the invention prepared as described under a) and the respective mixture in a refrigerator at about 6 ° C stored. The pot life was determined as in Example 1.

c) Preparation of a non-inventive comparison mixture from oxidizing agent and precursors not treated with an ion exchanger

As a comparison, a mixture of one part by weight of 3,4-Ethγlendioxythiophen (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight was not prepared with an ion exchanger-treated 40 wt .-% hydrochloric efhanolischer solution of iron (ITJ) -p-toluenesulfonate, this stored at approx. 6 ° C and also examined according to the above procedure (reference).

The following measured values resulted:

The mixtures according to the invention have a significantly longer pot life than the mixture with iron (ILT) -p-toluenesulfonate which has not been treated with an ion exchanger.

Example 3:

To determine the conductivity of polymer films which were produced from the mixtures according to the invention, films were spun on from the mixtures and then polymerized.

a> Preparation of a solution of an oxidizing agent according to the Invention

1 (Bayer AG) with the weakly basic, macroporous anion exchanger Lewatit ^® MP 62 and mixed: by analogy with Example 1, a 40 wt .-% strength butanolic solution of iron (ILT) -p-toluene sulfonate in a ratio of 2 was let the mixture rest for 64 h. The anion exchanger was then filtered off. b) Preparation of an inventive mixture of oxidizing agent and precursors as well as a conductive coating ^■

It -was a mixture consisting of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of as prepared under a) above prepared solution of the oxidizing agent according to the invention and a portion of this mixture on a glass slide (26 mm * 26 mm * l mm) by means of a spin coater (Chemat Technology KW-4A) at 2000 rpm for 5 seconds. The sample was dried at 20 ° C. for 60 min and then washed with methanol in a glass dish for 15 min. The sample was then dried at 50 ° C. for 15 minutes and the surface resistance was then determined using a four-point measurement with a Keithley 199 multimeter. The layer thickness was determined using a Tencor Alpha Step 500 Surface Profiler. The specific conductivity was determined from the surface resistance and layer thickness. The rest of the mixture was stored in a refrigerator at approx. 6 ° C. and the pot life was determined there, as described in Example 1.

c) Production of a comparative mixture according to the invention from oxidizing agent and precursors not treated with an ion exchanger

As a comparison, a mixture of one part by weight of 3,4-Ethylendioxyfhiophen (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight was not prepared with an ion exchanger-treated 40 wt .-% hydrochloric butanolic solution of iron (IU) -p-toluenesulfonate, this stored at 6 ° C and also examined according to the above methods (reference).

The following measured values resulted:

The mixture according to the invention has a significantly longer pot life than the mixture with an oxidizing agent not treated with an ion exchanger. At the same time, the conductivity of the layer is significantly greater and the surface resistance is significantly lower than for the sample which was produced from the reference mixture. Example 4:

The pot life of a mixture according to the invention was determined in comparison with a mixture of metal salt not treated with an ion exchanger and with added base.

a) 'Preparation of a solution of an oxidizing agent according to the Invention

For this purpose, analogous to Example 1, a 40 wt .-% strength butanolic solution of iron (III) -p-toluene sulfonate in a volume ratio of 2: 1 with the weakly basic anion exchanger Lewatit MP 62 macroporous ^® (Bayer AG), and the mixture left for 64 h. The anion exchanger was then filtered off.

b) Production of a mixture according to the invention of oxidizing agent and precursors

There was a mixture consisting of a part by weight of 3,4-ethylenedioxythiophene

(BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of the as described under a)

• Made solution of the oxidizing agent according to the invention. The mixture was stored in a refrigerator at approx. 6 ° C. and the pot life was determined there, as described in Example 1.

c) Preparation of a non-inventive comparison mixture from not with one

Ion exchanger treated oxidant and precursors

As a comparison, a mixture of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) 20 parts by weight is not treated with an ion exchanger 40 wt .-% hydrochloric butanolic solution of iron (ILI) -p-toluenesulfonate and 0.75 Ge - parts of imidazole produced, stored at 6 ° C and also examined according to the above methods (reference).

The following pot lives resulted:

Polymer films could be produced from both of the above mixtures by applying the mixture to a glass plate and drying at 60 ° C. For reference mixtures with larger additives imidazole However, no polymer films could provide more manufacturing ^• even at temperatures of 150 ° C.

The mixture according to the invention has a significantly longer pot life than the mixture with an oxidizing agent not treated with an ion exchanger and addition of the base imidazole.

Example 5:

The pot life of a mixture according to the invention which contains two differently produced oxidizing agents according to the invention was determined.

a) Preparation of two solutions of oxidizing agent according to the invention

For this purpose, analogous to Example 1, a 40 wt .-% ethanolic solution of iron (ITJ) -p-toluene-sulfonate in the volume ratio 1: 1 with the weakly basic anion exchanger Lewatit MP 62 macroporous ^® (Bayer AG) for 7 hours with mixed with a shaker, and then the anion exchanger was filtered off (solution 1).

A second solution was prepared analogously by using a 40 wt .-% ethanolic solution of iron (ITI) -p-toluenesulfonate in the volume ratio 2: basic 1 slightly with that anion exchanger Lewatit macroporous ^® MP 62 (Bayer AG) for 7 hours with mixed with a shaker, and then the anion exchanger was filtered off (solution 2).

b) • Production of a mixture according to the invention of oxidizing agent and precursors

A mixture according to the invention consisting of one part by weight of 3,4-ethylenedioxy thiophene (BAYTRON ^® M, HC Starck GmbH), 10 parts by weight of solution 1 and 10 parts by weight of solution 2 was prepared, and the mixture in a refrigerator at about 6 ° C stored. The pot life was determined analogously to Example 1.

The pot life was 96 hours.

As this example shows, the pot life can also be adjusted by mixing differently prepared oxidizing agents according to the invention.

Example 6:

The pot life of a mixture according to the invention was determined when stored at low temperature.

a) Preparation of a solution of an oxidizing agent according to the invention

For this purpose, analogous to Example 1, a 40 wt .-% ethanolic solution of iron (III) -p-toluene sulfonate in a volume ratio of 2: 1 with the weakly basic anion exchanger Lewatit MP 62 macroporous ^® (Bayer AG) for 7 hours with mixed with a shaker, and then the anion exchanger was filtered off.

A mixture consisting of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of the solution of the oxidizing agent of the invention prepared as described under a) was prepared, and the mixture in a freezer about -15 ° C stored. The mixture remained liquid at this temperature. The pot life was determined as in Example 1.

c) ^'the preparation of a comparative mixture of the invention from non-■ not ion-exchanged with a oxidizer and precursors

As a comparison, a mixture of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight was not prepared with an ion exchanger-treated 40 wt .-% ethanolic solution of iron (JJI) -p-toluenesulfonate, this stored at -15 ° C and also examined according to the above methods (reference).

The following measured values were obtained (the corresponding pot lives for storage at 6 ° C. from Example 2 are also listed as a comparison):

As the comparison of the pot lives at different storage temperatures shows, the pot life can be significantly increased by cooling to low temperatures both for the mixture according to the invention and for the reference. However, the mixtures according to the invention also have, at low temperatures, much longer pot lives than mixtures which do not contain iron (] Tf) -p-toluenesulfonate treated with an ion exchanger.

Example 7:

The pot lives of mixtures according to the invention which contain oxidizing agents according to the invention, which were prepared with different anion exchangers, were determined.

a) Preparation of solutions of the oxidizing agent according to the Invention

For this purpose, analogous to Example 1, a 40 wt .-% strength butanolic solution of iron (III) -p-toluene sulfonate in a volume ratio of 2: 1 with the weakly basic anion exchanger Lewatit MP 62 macroporous ^® (Bayer AG), and the mixture left for 24 hours. The anion exchanger was then filtered off. Analog -were invention .Oxidationsmittel by treating the iron (ILT) -p-toluenesulfonate solution with the medium basic, anion exchanger Lewatit MP 64 macroporous ^® (Bayer AG) or the strongly basic macroporous anion exchanger Lewatit ^® MP 600 WS (Bayer AG) manufactured.

b) Preparation of the mixtures according to the invention from oxidizing agent and precursors

A mixture consisting of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of the solution of the oxidizing agent of the invention prepared as described under a) was prepared, and the mixture in a refrigerator at about 6 ° C stored. The pot life was determined as in Example 1.

Analog were mixtures with the ^® by the same treatment with the mitt Elba rectangular, macroporous anion exchanger Lewatit MP 64 (Bayer AG) or the. strongly basic, macroporous anion exchanger Lewatit ^® MP 600 WS (Bayer AG) prepared as described under a), stored at 6 ° C and the samples also analyzed analogously.

As a comparison, a mixture of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight was not with an ion exchanger treated 40 wt .-% butanolic solution of iron (IH) p-toluenesulfonate prepared, stored at 6 ° C and also examined according to the above methods (reference).

The following measured values resulted:

Example 8:

A solution of an oxidizing agent according to the invention with a low water content and high storage stability was prepared.

a) Preparation of a solution of an oxidizing agent according to the invention with a low water content

To this was added 1 1 of weak base, macroporous anion exchanger Lewatit MP 62 ^® (Bayer AG) with 2 1 of absolute ethanol and stirred for 6 hours. The exchange resin was then separated off via a sieve and conditioned three more times as described.

Then, analogously to Example 1, a 40% by weight ethanolic solution of iron (m) - p-toluenesulfonate in a volume ratio of 2: 1 (based on the volume of the ion exchanger before the treatment with ethanol) was used with the weakly basic, macroporous anion exchanger Lewatit ^® MP 62 (Bayer AG) mixed for 7 hours with a shaker, and then the anion exchanger was filtered off.

b) Preparation of a solution of an oxidizing agent according to the invention without pretreating the ion exchanger

Analogously to Example 1, a 40 wt .-% ethanolic solution of iron (H [) - p-toluene sulfonate in a ratio of 2: basic 1 slightly with that anion exchanger Lewatit macroporous ^® MP 62 (Bayer AG) for 7 hours with mixed with a shaker, and then the anion exchanger was filtered off.

The solution of the oxidizing agent according to the invention after preparation a) had a water content of 1.1% by weight, based on the total weight of the solution, and the solution showed no precipitation after three months' storage at room temperature (20 ° C.). The solution of the oxidizing agent according to the invention after preparation b) had a water content of 12.8% by weight, based on the total weight of the solution. The solution showed precipitations after one week when stored at room temperature, and precipitated after two months when stored at about 6 ° C. in the refrigerator.

Example 9:

The pot life of a mixture according to the invention containing an oxidizing agent according to the invention with a low water content was determined.

a) Preparation of a mixture of oxidizing agent and precursors according to the invention

A mixture was prepared consisting of one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of the solution of the oxidizing agent according to the invention prepared as described in Example 8a). The mixture was stored in a refrigerator at approx. 6 ° C. and the pot life was determined there, as described in Example 1.

b) Production of a mixture according to the invention from oxidizing agent and precursors with the addition of water

A mixture was prepared consisting of one part by weight 3,4-Ethylendioxyfhiophen (BAYTRON ^® M, HC Starck GmbH), 20 parts by weight of the solution of the oxidizing agent according to the invention prepared as described in Example 8a) and 2 parts of water. The mixture was stored in a refrigerator at approx. 6 ° C. and the pot life was determined there, as described in Example 1.

The mixture according to the invention from a) had a pot life of 2.5 hours, the mixture from b) according to the invention had a pot life of 30 hours.

Example 10:

Production of capacitors using the oxidizing agent according to the Invention

Tantalum powder with a specific capacity of 50,000 μFV / g was pressed into pellets and sintered to form a porous, cylindrical body measuring 2.5 mm in diameter and 1.9 mm in height. The pellets (anodes) were anodized to 30 V in a phosphoric acid electrolyte. ^• A 40 wt .-% ethanolic solution of iron (ITI) -p-toluenesulfonate was added to Example 1 in the volume ratio 2 analog: 1 basic weakly to the anion exchangers Lewatit macroporous ^® MP 62 (Bayer AG) were mixed for 7 hours with a shaker , and then the anion exchanger was filtered off.

A mixture consisting of the oxidizing agent prepared according to the invention from one part by weight 3,4-ethylenedioxythiophene (BAYTRON ^® M, HC Starck GmbH) and 20 parts by weight of the solution prepared as described under a).

The mixture according to the invention was used to impregnate the anode pellets. The anode pellets were soaked in this mixture and then dried for 15 min at room temperature, 15 min at 50 ° C and 15 min at 150 ° C. After the heat treatment, the mixture in the pellets was polymerized. The pellets were then washed in methanol for 30 minutes. The impregnation and washing described was carried out two more times. Finally, the pellets were coated with a graphite and a silver layer.

The same procedure was carried out on the same mixture according to the invention on new pellets after the mixture was 24 hours old and had been stored at 6 ° C. during this time.

After the mixture of the invention was 72 hours old and had been stored at 6 ° C. during this time, it was filtered and the process was carried out again on new pellets.

The capacitors had the following electrical values:

The capacitance was determined at 120 Hz and the equivalent series resistance at 100 kHz using an LCR meter (Agilent 4284A). There are no significant differences in the electrical values. Example ll:

Determination of the activation energy of mixtures according to the invention and mixtures not according to the invention

The following describes how the activation energies of the polymerization were determined in mixtures containing 3,4-ethylenedioxyfhiophene as precursors and iron (IIT) -p-toluenesulfonate as the oxidizing agent. Here, a comparison was made between mixtures with untreated iron (iπ) -p-toluenesulfonate and ^'inventively treated with ion exchangers iron (iπ) - p-toluenesulfonate was carried out.

Kinetic model for the polymerization of 3,4-ethylenedioxythiophene with EisendTD-p-toluene sulfonate

The reaction of 3,4-ethylenedioxythiophene (EDT) with iron (JJI) p-toluenesulfonate was followed using the EDT, Fe (m) and Fe (II) concentrations in solutions of the reactive mixture. Since the product poly- (3,4-ethylenedioxythiophene) is insoluble and precipitates out of the solution, its course of concentration cannot be followed directly.

To determine the course of the concentration, reactive mixtures of EDT and alcoholic solutions of Fe (m) -p-toluenesulfonate were prepared and the mixture was stored in temperature-controlled, sealed containers with stirring. A sample was taken at regular intervals and the EDT, Fe (ITI) and Fe (IT) content determined. The EDT concentration was determined by HPLC (high performance liquid chromatography). Iron (II) and iron (πr) concentrations were determined photometrically.

The reaction scheme for the oxidative polymerization of EDT with iron (ITi) -p-toluenesulfonate to form conductive poly (3,4-ethylenedipxythiophene) is shown in FIG. 1.

Figure 1: Reaction scheme for the oxidative polymerization of EDT with iron (ITI) -p-toluenesulfonate to conductive poly- (3 _; 4-ethylenedioxythiophene).

This reaction can be described by the following partial reaction steps:

^π monomer oxidation

^{? "} θ ⁼ ^ 0 ^C EDT ^C f _e "'^""^"" - ^' 01 ^C H * ^C EDT 'p _e ^m

koi describes an acceleration of the reaction due to the acid released during the oxidation.

^Q end group oxidation

+ ^C polymer ^C Fe "

kπ describes an acceleration of the reaction due to the acid released during the oxidation.

^■ Chain growth through radical (cation) combination and deprotonation

r ¹ - κ ^l ~ c radical

polymer oxidation

^{'' k} D ^C _F p _ee a ^m V "'Repeating units oxidation sites

"-D ~ ' ^C -D ^C F fJ _e "' ^C. oxidation sites

repeat

The experimentally determined reaction constants for the oxidative polymerization of EDT with iron (J I) -p-toluenesulfonate to oxidized poly-3,4-ethylenedioxythiophene at 30 ° C. are shown in the following table.

The rate-determining reaction step is the monomer oxidation (ko).

With the help of the constants from the table above, the concentration profiles of EDT, Fe (πi) and Fe (H) can be described very well for different initial concentrations. Figure 2 shows an example of a comparison between the experimental process and the model simulation.

Figure 2: Comparison of experimental data of the concentration profile of EDT (■ square), Fe (πi) (f diamond) and Fe (LT) (A triangle) at 30 ° C with model simulation (solid lines).

Determination of the activation energy for the polymerization of 3,4-ethylenedioxythiophene with untreated iron (LTr) -n-tothiosulfonate

To determine the activation energy, the concentration curve was determined at different temperatures (10 ° C, 20 ° C, 30 ° C, 40 ° C, 50 ° C) and the rate-determining one Reaction constant ko adjusted in each case. From the Arrhenius plot (see FIG. 3), the activation energy was found to be 67 kJ / mol and the frequency factor was 5.2 * 10 ¹⁰ mol ^ h ^"1 .

Figure 3: Arrhenius plot of the velocity coefficient o (symbols φ: experimental data, line: simulation).

Determination of the activation energy for the polymerization of 3,4-ethylenedioxymiophene in mixtures according to the invention

A mixture according to the invention, consisting of 6.3 parts by weight of 3,4-ethylenedioxy thiophene (BAYTRON ^® M, HC Starck GmbH), 85.2 parts by weight of the solution prepared as described under Example 8a) of the oxidation agent of the invention and 8.5 parts by weight Water.

The reaction rate for the polymerization with the oxidizing agent according to the invention is significantly lower than the corresponding reactions with untreated oxidizing agent. FIG. 4 shows the concentration profile of EDT in the mixture according to the invention in comparison to the simulation with the reaction constants for the untreated oxidizing agent.

Figure 4: Experimentally determined monomer concentration curve (symbols ♦) for the polymerisation of EDT in mixtures according to the invention at 20 ° C. in comparison to simulations (solid line) with the model constant developed for the untreated oxidizing agent.

In order to adapt the existing model to the experimental data, the kinetic parameters for the oxidation steps 7c ₀ , k ₀ _, k, k _{n were} scaled with the same factor. This took into account the slower rate of the oxidation steps. All other parameters were left unchanged. FIG. 5 shows that the experimental concentration curves can be described very well using the model.

Figure 5: Experimental concentration profiles of EDT, Fe (III) and Fe (U) (symbols) at 20 ° C and associated simulations (lines).

To determine the activation energy, the concentration curve was determined at different temperatures (20 ° C, 30 ° C, 45 ° C) and the rate-determining reaction constant o was adjusted in each case. The Arrhenius evaluation is shown in FIG. 6. An activation energy of 100 kJ / mol is obtained. The frequency factor is 2.4-10 ¹⁴ l'mor'h ^"1 . Figure 6: Arrhenius evaluation of the speed coefficient ko for the monomer oxidation (symbols: experimental values, line: simulation).

Due to the higher activation energy, the polymerization in the mixture according to the invention is significantly slower than in mixtures with untreated oxidizing agent.

Claims

Patentansprflche

1. A process for the preparation of an oxidizing agent for the production of conductive polymers, characterized in that a metal salt of an organic acid or inorganic acid having organic residues is treated with an ion exchanger.

2. A method for producing an oxidizing agent according to claim 1, characterized in that an anion exchanger is used as the ion exchanger.

3. A method for producing an oxidizing agent according to claim 1 or 2, characterized in that a weakly basic anion exchanger is used as the ion exchanger.

4. A method for producing an oxidizing agent according to at least one of claims 1 to 3, characterized in that the metal salt is a transition metal salt.

5. A process for producing an oxidizing agent according to claim 4, characterized in that - the transition metal salt is an iron (m) salt.

6. A method for producing an oxidizing agent according to at least one of claims 1 to 5, characterized in that the rest of the organic acid is a residue of a sulfonic acid.

7. A method for producing an oxidizing agent according to at least one of claims 1 to 6, characterized in that it is the transition metal salt

Fe (IU) -p-toluenesulfonate, Fe (III) -o-toluenesulfonate or a mixture of Fe (JJf) -p-toluenesulfonate and ^• Fe (IIJ) -o-toluenesulfonate is.

8. A method for producing an oxidizing agent according to at least one of claims 1 to 7, characterized in that the method is carried out in the presence of one or more solvents.

9. A method for producing an oxidizing agent according to at least one of claims 1 to 8, characterized in that one or more alcohol (s), water or a mixture of one or more alcohol (s) and water are used as the solvent or solvents.

10. A method for producing an oxidizing agent according to at least one of claims 1 to 9, characterized in that the alcohol or alcohols is butanol, ethanol or methanol.

11. A method for producing an oxidizing agent according to at least one of claims 1 to 10, characterized in that the oxidizing agent is separated from the solvent after treatment with the ion exchanger and, if appropriate, is dissolved again in the same or different solvent.

12. Oxidizing agent obtainable by a process according to at least one of claims 1 to 11.

13. Oxidizing agent according to claim 12, ^' characterized in that it is in solution and the solution has a water content of 0 to 10 wt .-% based on the total weight of the solution.

14. Use of the oxidizing agent according to claim 12 or 13 as a retarding oxi. dation agent in the oxidative polymerization of precursors for the production of conductive polymers.

15. Mixture containing precursors for the production of conductive polymers and one or more oxidizing agents according to claim 12 or 13 and optionally one or more solvents, characterized in that the formation of polymers in the mixture is delayed.

16. Mixture according to claim 15, characterized in that optionally substituted 3,4-ethylenedioxythiophene or • its derivatives are used as precursors for the production of conductive polymers.

17. Mixture according to claim 15 or 16, characterized in that it contains water.

18. Mixture according to at least one of claims 15 to 17, characterized in that it contains counterions.

19. Mixture according to at least one of claims 15 to 18, characterized in that it contains one or more binders, crosslinking agents and / or additives.

20. Mixture containing precursors for the production of conductive polymers and at least one oxidizing agent, characterized in that the polymerization of the precursors has an activation energy of 75 kJ / mol or greater.

21. Mixture according to claim 20, characterized in that it contains optionally substituted 3,4-ethylenedioxythiophene or its derivatives as precursors for the production of conductive polymers.

22. Mixture according to claim 20 or 21, characterized in that it contains a transition metal salt, preferably an iron (IH) salt, as the oxidizing agent.

23. A method for producing an electrolytic capacitor, characterized in that a mixture according to at least one of claims 15 to 22, optionally in the form of solutions, is applied to an oxide layer of a metal and chemically oxidatively at temperatures of from -10 ° C to 250 ° C to the corresponding Polymers are polymerized.

.

24. Procedure. for the production of an electrolytic capacitor, characterized in that

Precursors for the production of conductive polymers and oxidizing agents according to claim

12 or 13, one after the other, optionally in the form of solutions, are applied to an oxide layer of a metal and are chemically oxidatively polymerized at temperatures from -10 ° C. to 250 ° C. to give the corresponding polymers.

25. The method according to claim 23 or 24, characterized in that the oxidizable metal is a valve metal or a compound with comparable properties.

26. The method according to at least one of claims 23 to 25, characterized in that the valve metal or the compound with comparable properties is tantalum, niobium, aluminum, titanium, zirconium, hafnium, vanadium, an alloy or compound of at least one of these Metals with other elements, NbO or an alloy or compound of NbO with other elements

27., Method for producing conductive layers, characterized in that a mixture according to at least one of claims 15 to 22, optionally in the form of

Solutions are applied to a base and polymerized on this base chemically oxidatively at temperatures from -10 ° C to 250 ° C to the corresponding conductive polymers.

28. Process for the production of conductive layers, characterized in that precursors for the production of conductive polymers and oxidizing agents according to claim 12 or 13 are applied in succession, optionally in the form of solutions, and be polymerized on this base chemically oxidatively at temperatures from -10 ° C to 250 ° C to the corresponding conductive polymers.

29. The method according to claim 23 and 28, characterized in that counterions are added to the solutions.

30. The method according to at least one of claims 23 to 29, characterized in that optionally substituted thiophenes, pyrroles, anilines or their derivatives are used as precursors for the production of conductive polymers.

31. The method according to claim 30, characterized in that optionally substituted alkylene-3,4-dioxythiopenes or their derivatives are used as optionally substituted thiophenes or their derivatives.

32. The method according to claim 31, characterized in that 3,4-ethylenedioxythiophene is used as optionally substituted alkylene-3,4-dioxythiophene.

33. The method according to at least one of claims 23 to 32, characterized in that the solutions additionally contain one or more binders, crosslinking agents and / or additives.

34. The method according to at least one of claims 23 to 33, characterized in that the counterions are anions of monomeric or polymeric alkane or cycloalkanesulfonic acids or aromatic sulfonic acids.

35. The method according to at least one of claims 23 to 34, characterized in that the layer containing the polymers (electrolyte layer) after the polymerization and

, optionally after drying with suitable solvents to remove excess oxidizing agent and residual salts.

36. Use of the oxidizing agent according to claim 12 or 13 for the production of conductive layers or electrolytic capacitors.

37. Use of the mixture according to at least one of claims 15 to 22 for the production of conductive layers or electrolytic capacitors.