Process for manufacturing a layer composition

Abstract

The present invention relates to a process for manufacturing a layer composition (9), comprising the following process steps: a) providing a substrate (10) having a substrate surface (11); b) forming a stable conductive polymer layer (12) on at least a part of the substrate surface (11), the formation of the stable conductive polymer layer (12) comprising the following process steps: b1) forming a conductive polymer layer (13) comprising a conductive polymer on at least a part of the substrate surface (11); b2) applying a liquid stabilizer phase comprising at least one stabilizer (7) and at least one solvent or dispersant to the conductive polymer layer (13) obtained in process step b1) for the formation of the stabilizer layer (14), wherein the at least one stabilizer (7) is a flavonoid. The present invention also relates to a layer composition and to the use of the layer composition.

Description

[0001] The present invention generally relates to a process for manufacturing a layer composition, such as by treating a conductive polymer with a stabilizer, a layer composition, and the use of such a layer composition.

[0002] Conductive polymers from the polypyrrole, polyaniline, and polythiophene classes are known from the literature. In particular, poly(3,4-alkylenedioxythiophene) dispersions have recently gained technical importance, as they can be used, for example, for manufacturing conductive or antistatic coatings (see, for example, EP 440 957 A1). However, in practice, it has been found that the conductivity of coatings from such dispersions is not always sufficiently stable for practical applications at higher temperatures.

[0003] EP 1 798 259 A1 and WO 2008 / 055834 A1 describe that the thermal stability of the conductivity of coatings containing polythiophene dispersions can be increased if, for example, derivatives of gallic acid (3,4,5-trihydroxybenzoic acid) are added. However, the addition of these stabilizers generally causes the dispersions used to become unstable. In addition, these stabilizers cannot be added to the reactive mixture of monomers and oxidants used for manufacturing conductive coatings, as these stabilizers interfere with the oxidative polymerization, for example, by complexing with the oxidant.

[0004] Therefore, there is still a need for processes for manufacturing conductive layers and layer compositions containing these from conductive polymers with improved temperature stability.

[0005] One of the main application areas of conductive layer compositions containing conductive polymers is solid electrolyte capacitors.

[0006] Commercially available electrolyte capacitors generally consist of a porous metal electrode, an oxide layer on the metal surface, a conductive material (usually solid) introduced into the porous structure, an external electrode (contact) such as, for example, a silver layer, and additional electrical contacts and encapsulations. Frequently used electrolyte capacitors are tantalum electrolyte capacitors, the anode electrode of which is made of the valve metal tantalum, on which a uniform tantalum pentoxide dielectric layer has been formed by anodic oxidation (also known as "forming"). A liquid or solid electrolyte forms the cathode of the capacitor. In addition, aluminum capacitors are often used, the anode electrode of which is made of the valve metal aluminum, on which a uniform electrically insulating aluminum oxide layer has been formed by anodic oxidation as the dielectric. Here, in addition, a liquid electrolyte or a solid electrolyte forms the cathode of the capacitor. Aluminum capacitors are generally constructed as wound capacitors or stacked capacitors.

[0007] π-conjugated polymers are particularly suitable as solid electrolytes in the above-mentioned capacitors due to their high electrical conductivity. π-conjugated polymers are also known as conducting polymers or synthetic metals. Their economic importance is increasing because polymers are superior to metals in terms of processability, weight, and the targeted adjustment of properties through chemical modification. Examples of known π-conjugated polymers are polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene, and poly(p-phenylene-vinylene). A particularly important polythiophene used technically is poly(3,4-ethylenedioxythiophene) (PEDOT) because it has a very high electrical conductivity in its oxidized form.

[0008] Solid electrolytes based on conducting polymers can be applied to the oxide layer in various ways and manners. For example, EP0 340 512 A1 describes the preparation of a solid electrolyte from 3,4-ethylenedioxythiophene and its use in an electrolyte capacitor. According to the teaching of this disclosure, 3,4-ethylenedioxythiophene is polymerized in situ onto the oxide layer.

[0009] On the other hand, DE-A-10 2005 043828 describes a process for manufacturing a solid electrolyte in a capacitor, in which a dispersion containing already polymerized thiophene (for example, a PEDOT / PSS dispersion known from the prior art) is applied to the oxide layer, and then the dispersant is removed by evaporation. In this context, WO 2012 / 041507 A1 discloses a process for manufacturing a layer composition, in which a stabilizer layer is applied to a conducting polymer layer preferably based on PEDOT / PSS, and in which the stabilizer is an aromatic compound having at least two OH groups. The preferred stabilizer used in WO 2012 / 041507 A1 is tannic acid.

[0010] Generally, the object of the present invention is to eliminate or at least mitigate the disadvantages arising from the prior art.

[0011] Furthermore, an object of the present invention is to provide layer compositions that can be easily manufactured and exhibit good properties in capacitors and other applications, such as antistatic layer compositions. In addition, a process for manufacturing these layer compositions is provided, which can be easily used commercially, especially in the above-mentioned applications.

[0012] Another object is to improve the thermal stability of such layer compositions, preferably under high temperature and high humidity conditions, and especially as polymer solid electrolyte capacitors.

[0013] Furthermore, an object according to the present invention is to provide a layer composition which, in particular as a capacitor, exhibits advantageous properties such as an as low as possible increased equivalent series resistance (ESR) and also an as low as possible increased dissipation factor, while having an as constant as possible capacitance during exposure to heat or heat and humidity. In the case of a layer, an as low as possible increase in surface resistance is to be achieved when treated with heat or heat and humidity.

[0014] The contribution to achieving at least one of the above objects is made by a process for manufacturing a layer composition, which process comprises the following process steps:

[0015] a) providing a substrate having a substrate surface;

[0016] b) forming a stable conductive polymer layer on at least a part of the substrate surface, the formation of the stable conductive polymer layer comprising the following process steps:

[0017] b1) forming a conductive polymer layer comprising a conductive polymer on at least a part of the substrate surface;

[0018] b2) applying a liquid stabilizer phase comprising at least one stabilizer and at least one solvent or dispersant to the conductive polymer layer obtained in process step b1) for the formation of the stabilizer layer, wherein the at least one stabilizer is a flavonoid.

[0019] It has been found completely surprisingly that using a stabilizer selected from the group consisting of flavonoids, gallic acid or mixtures thereof in the form of a stabilizer layer applied to the layer of the conductive polymer (especially in a capacitor) leads to a significant improvement in the thermal stability of the layer or the capacitor.

[0020] Herein, the conductive layer is understood to also refer, inter alia, to those layers which already have a low electrical conductivity and are usually also referred to as antistatic layers. Generally, the electrical conductivity of the layers means that these layers have a conductivity preferably in the range from 1 μS / cm to 10,000 S / cm.

[0021] First, a substrate is provided in process step a) of the process according to the invention. The substrate can be made of, for example, paper, polymer, glass or ceramic. For optical applications, the substrate is preferably transparent or light-transmissive. The transparent substrate can be made of glass, ultra-thin glass (flexible glass) or plastic. Particularly suitable plastics are: polycarbonate, polyester such as, for example, PET and PEN (polyethylene terephthalate or polyethylene naphthalate), copolycarbonate, polysulfone, polyethersulfone (PES), polyimide, polyethylene, polypropylene or cyclic polyolefin or cyclic olefin copolymer (COC), hydrogenated styrene polymer or hydrogenated styrene copolymer. Rigid or flexible substrates can be used.

[0022] In certain embodiments of this use, such as in capacitors, it is preferred that the substrate comprises an electrode body of electrode material, the surface of which is at least partially covered by a dielectric. In the present invention, the electrode body coated with a dielectric is referred to as an anode body. In addition to the electrode and the dielectric, the anode body may also have additional layers. The surface of the anode body (usually the dielectric, which may optionally also have additional layers) is the substrate surface in the context of the present invention.

[0023] In principle, the electrode body can be prepared by pressing a high-surface-area valve metal powder and sintering it to obtain a mostly porous electrode body. The electrical contact wires of preferably valve metals (such as tantalum for example) are usually also pressed into the electrode body. Then, the electrode body is coated with a dielectric (i.e., an oxide layer), for example by electrochemical oxidation. Alternatively, a metal foil can also be etched and coated with a dielectric by electrochemical oxidation in order to obtain an anode foil with porous regions. In a wound capacitor, the anode foil with porous regions (which forms the electrode body) and the cathode foil are separated by a separator and wound.

[0024] In the context of the present invention, valve metals should be understood to mean those metals whose oxide layer does not allow current to flow evenly in both directions. In the case of applying a voltage to the anode, the oxide layer of the valve metal blocks the current, while in the case of applying a voltage to the cathode, a large current appears, which can damage 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 best-known representatives of valve metals are Al, Ta, and Nb. Compounds having electrical properties comparable to those of valve metals are those having metallic conductivity, which can be oxidized and whose oxide layer has the above properties. For example, NbO has metallic conductivity but is generally not regarded as a valve metal. However, the layer of oxidized NbO has the typical properties of a valve metal oxide layer, such that NbO or alloys or compounds of NbO with other elements are typical examples of such compounds having electrical properties comparable to those of valve metals. Electrode materials having tantalum, aluminum, and those based on niobium or niobium oxide are preferred. Tantalum is particularly preferred as an electrode material.

[0025] To manufacture an electrode body that often has porous regions, the valve metal can be sintered in powder form, for example, to obtain a substantially porous electrode body, or a porous structure can be imprinted onto a metal body. The latter can be carried out, for example, by etching a foil.

[0026] For the sake of simplicity, a body having a porous region is also referred to hereinafter as porous. Thus, for example, an electrode body having a porous region is also referred to as a porous electrode body. In one aspect, the porous body can be penetrated by a plurality of channels and is thus sponge-like. This is often the case if tantalum is used in the construction of a capacitor. Additionally, only the surface can have pores and the subsequent region below the surface pores is structurally solid. This is often observed if aluminum is used in the capacitor construction.

[0027] Then, by applying a voltage, the generally porous electrode body thus produced is oxidized, for example in a suitable electrolyte (such as an aqueous solution of phosphoric acid or ammonium adipate), to form a dielectric. The level of this forming voltage depends on the oxide layer thickness to be achieved or the subsequent operating voltage of the capacitor. The preferred forming voltage is in the range from 1 V to 1000 V, particularly preferably in the range from 5 V to 200 V, even more particularly preferably in the range from 10 V to 100 V and most preferably in the range from 20 V to 70 V.

[0028] The generally employed porous electrode body preferably has a porosity of 10% to 90%, preferably 30% to 80%, particularly preferably 50% to 80%, and an average pore diameter of 10 nm to 10,000 nm, preferably 50 nm to 5,000 nm, particularly preferably 100 nm to 3,000 nm.

[0029] If the layer composition according to the invention is an aluminum wound capacitor or part of such an aluminum wound capacitor, the anode body is provided as a substrate as follows: In process step a), a porous aluminum foil is formed anodically as the electrode material, thereby forming an aluminum oxide coating as the dielectric. Then the aluminum foil thus obtained (anode foil) is provided with contact lines and is also wound with a further aluminum foil (cathode foil) provided with contact lines, the two foils being spaced apart from each other by one or more separator papers based on, for example, cellulose or preferably based on synthetic paper. After being wound, the anode body thus obtained is fixed, for example, by an adhesive tape. The one or more separator papers can be carbonized by heating in an oven. This method and manner of manufacturing the anode body of an aluminum wound capacitor are well known from the prior art and are described, for example, in US 7,497,879 B2.

[0030] In process step b) of the process according to the invention, then a stable conductive polymer layer comprising a conductive polymer is formed on at least a part of the substrate surface, and the formation of this stable conductive polymer layer comprises the following process steps:

[0031] b1) forming a conductive polymer layer comprising a conductive polymer on at least a part of the substrate surface;

[0032] b2) Applying a liquid stabilizer phase comprising at least one stabilizer and at least one solvent or dispersant to the conductive polymer layer obtained in process step b1) for forming a stabilizer layer, wherein the at least one stabilizer is gallic acid, flavonoid or a mixture thereof.

[0033] To form a conductive polymer layer comprising a conductive polymer in process step b1), a solution or dispersion of a conductive polymer precursor (hereinafter referred to as precursor), a solution of a conductive polymer or a dispersion comprising conductive polymer particles (preferably with a dispersant) is applied to a substrate. If the anode body is used as the substrate, the precursor, solution or dispersion is introduced into the porous region of the anode body. Generally, a dispersion containing conductive polymer particles can be used. However, according to a specific embodiment of the process of the present invention, in process step b), a stable conductive layer comprising a conductive polymer is formed in situ on at least a part of the substrate surface.

[0034] The above solution or dispersion is applied to the substrate surface by known processes such as dipping, dip coating, casting, drop coating, spraying, fog coating, knife coating, brush coating or printing (e.g., inkjet printing, screen printing or pad printing). For the anode body, the application is preferably carried out by immersing the anode body provided in process step a) into the solution or dispersion and thus impregnating it with the solution or dispersion. The immersion or impregnation is preferably carried out for a period in the range of 1 second to 120 minutes, particularly preferably in the range of 10 seconds to 60 minutes, and most preferably in the range of 30 seconds to 15 minutes. The introduction of the solution or dispersion into the anode body can be promoted, for example, by increasing or decreasing the pressure, vibration, ultrasound or heat. These conditions are also preferred for other layer compositions.

[0035] The content of the stabilizer in the solution or dispersion comprising the conductive polymer or precursor is preferably less than 0.2% by weight, particularly preferably less than 0.1% by weight, and very particularly preferably less than 0.01% by weight, in each case based on the total weight of the solution or dispersion. The solution or dispersion is extremely preferably free of stabilizers. The stabilizer in the solution or dispersion easily causes an undesired reduction in the storage stability of the solution or dispersion containing the conductive polymer or conductive polymer precursor.

[0036] The application of the precursor, solution or dispersion can be carried out directly on the substrate or using an adhesion promoter (e.g., a silane such as an organofunctional silane or its hydrolysis product, e.g., 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane or octyltriethoxysilane) and / or one or more other functional layers.

[0037] If the anode body is used as the substrate, due to the application, the solution or dispersion preferably covers the pores of the porous region quite sparingly. Instead, the surface of the cavities of the pores is at least partially coated with the dispersion. The particles present in the dispersion thus not only form a layer covering the openings of the pores; at least part and usually all regions of the pore surface are also covered with a layer of the particles of the dispersion, thereby introducing these particles into the anode body.

[0038] The corresponding monomers are understood, for example, as precursors for the preparation of conductive polymers. Mixtures of various precursors can also be used. Suitable monomer precursors are, for example, optionally substituted thiophenes, pyrroles or anilines, preferably optionally substituted thiophenes, particularly preferably optionally substituted 3,4-alkylenedioxythiophenes.

[0039] The term "polymer" as used in the context of the present invention includes all compounds having more than one identical or different repeating units in the context of the present invention.

[0040] "Conductive polymer" should be understood here in particular to mean a class of compounds of π-conjugated polymers which have electrical conductivity after oxidation or reduction. Preferably, a conductive polymer is understood to mean those π-conjugated polymers which have a conductivity of about at least 0.1 S cm -1 after oxidation.

[0041] The conductive polymer preferably contains at least one polythiophene, polypyrrole or polyaniline, which are optionally substituted. Particularly preferably, the conductive polymer contains at least one polythiophene. Preferred polythiophenes are those having repeating units of general formula (I), general formula (II), general formula (III) or polythiophenes containing a combination of these repeating units:

[0042]

[0043] where

[0044] A is an optionally substituted C 1 -C 5 -alkylidene group,

[0045] R is independently H, a straight-chain or branched optionally substituted C 1 -C 18 -alkyl group, an optionally substituted C 5 -C 12 -cycloalkyl group, an optionally substituted C 6 -C 14 -aryl group, an optionally substituted C 7 -C 18 -aralkyl group, an optionally substituted C 1 -C 4-hydroxyalkyl group or hydroxy group,

[0046] x is an integer from 0 to 8, and

[0047] where multiple R groups are bonded to A, they may be the same or different.

[0048] The general formulas (I) and (II) are to be understood such that the x substituents R can be bonded to the alkylene group A.

[0049] Particularly preferred polythiophenes have repeating units of the general formula (I) or (II) or repeating units of the general formulas (I) and (II), where A is an optionally substituted C 2 -C 3 -alkylene group and x is 0 or 1. A very particularly preferred polythiophene is poly(3,4-ethylenedioxythiophene) (PEDOT), which is optionally substituted with poly(4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxacyclohexen-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxacyclohexen-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S) or poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxacyclohexen-2-yl)methoxy]butane-2-sulfonic acid).

[0050] In the context of the present invention, the prefix "poly" is to be understood as meaning that in the polymer or polythiophene there are more than one identical or different repeating units. The polythiophene contains a total of n repeating units of general formula (I), or general formula (II), or general formula (III), or general formula (I) and (II), or general formula (I) and (III), or general formula (II) and (III), or general formula (I), (II) and (III), where n is an integer from 2 to 2000, preferably from 2 to 100. The repeating units of general formula (I) or general formula (II) or general formula (III), or the repeating units of general formula (I) and (II), or the repeating units of general formula (I) and (III), or the repeating units of general formula (II) and (III), or the repeating units of general formula (I), (II) and (III) may each be the same or different in the polythiophene. Preferred polythiophenes have in each case the same repeating units of general formula (I) or general formula (II) or general formula (III), or in each case the same repeating units of general formula (I) and (II), or general formula (I) and (III), or general formula (II) and (III), or in each case the same repeating units of general formula (I), (II) and (III). Particularly preferred polythiophenes have in each case the same repeating units of general formula (I) or general formula (II), or in each case the same repeating units of general formula (I) and (II). At the end groups, the polythiophenes preferably each carry H.

[0051] In the context of the present invention, C 1 -C 5 -alkylene group A is preferably methylene, ethylene, n-propylene, n-butylene or n-pentylene. C 1 -C 18 -alkyl R is preferably a straight-chain or branched C 1 -C 18 -alkyl group, such as methyl, ethyl, n-propyl or isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 1,1-dimethylpropyl, 1,2-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 -C 12 -cycloalkyl group R is, for example, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclodecyl, C 6 -C 14 -aryl R is, for example, phenyl or naphthyl, and C 7 -C 18- The aralkyl group R is, for example, benzyl, o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 3,4-xylyl, 3,5-xylyl or mesityl. The above listing is used to illustrate the present invention by way of example and should not be considered exclusive.

[0052] In the context of the present invention, any additional substituents of the A group and / or the R group include many organic groups such as alkyl, cycloalkyl, aryl, aralkyl, alkoxy, halogen, ether, thioether, disulfide, sulfoxide, sulfone, sulfonate ester, amino, aldehyde, ketone, carboxylate ester, carboxylic acid, carbonate, carboxylate, cyano, alkylsilane and alkoxysilyl groups, and also formamide groups.

[0053] The polythiophenes can be uncharged or cationic. In a preferred embodiment, they are cationic, and "cationic" only refers to the charge remaining on the main polythiophene chain. Depending on the substituents on the R group, the polythiophenes can carry positive and negative charges within the structural unit. In this case, the positive charge is on the polythiophene main chain, and the negative charge (if present) is on the R group substituted with a sulfonate or carboxylate group. The positive charge on the polythiophene main chain can be partially or completely saturated by anionic groups that may be present on the R group. Overall, the polythiophenes in these cases can be cationic, uncharged or even anionic. However, in the context of the present invention, all are considered cationic polythiophenes because the positive charge on the polythiophene main chain is crucial. The positive charge is not shown in the formula because its exact number and position cannot be clearly represented. However, the number of positive charges is at least 1 and at most n, where n is the total number of all repeating units (identical or different) within the polythiophene.

[0054] The positive charge of the polythiophene can be balanced by an R group substituted with a sulfonate or carboxylate and thus negatively charged (so-called "self-doped polythiophene") or a counterion (so-called "externally doped polythiophene").

[0055] According to the polythiophene that can be used to form the conductive polymer layer in process step b1), a first preferred embodiment for forming the solid electrolyte layer in a capacitor, the polythiophene is a self-doped polythiophene, and the self-doped polythiophene preferably contains at least 50%, still more preferably at least 75%, still more preferably at least 95%, and most preferably 100% of the repeating units of formula (IV)

[0056]

[0057] where

[0058] X, Y are the same or different and represent O, S, N-R1 ,

[0059] Z represents an organic residue with at least one anionic substituent, preferably -SO3-M + group, where M + represents a cation, such as Li + , Na + , K + or NH 4 + , where Z preferably represents -(CH 2 ) m -CR 2 R 3 -(CH 2 ) n– ,

[0060] R 1 represents aryl, C 1 -C 18 -alkyl or hydrogen,

[0061] R 2 represents hydrogen, -(CH 2 ) S -O-(CR 4 2 ) p -SO 3 - M + or -(CH 2 ) p -SO 3 - M + ,

[0062] R 3 represents -(CH 2 ) S– O-(CR 4 2 ) p -SO 3 - M + or -(CH 2 ) p -SO 3 - M + ,

[0063] M + represents a cation,

[0064] m, n are the same or different and represent integers from 0 to 3,

[0065] R 4 represents hydrogen or C 1- C10 an alkyl group, preferably a methyl group,

[0066] s represents an integer from 0 to 10, and

[0067] p represents an integer from 1 to 18.

[0068] In this context, the above percentage numbers are intended to represent the numerical content of the units of formula (IV) in the total number of monomer units of the self-doped conductive polymer.

[0069] Suitable cations M + are, for example, H + 、Li + 、Na + 、K + 、Rb + 、Cs + and NH 4 + . Particularly suitable cations are Na + and K + .

[0070] Particularly preferred monomers of formula (IV) are monomers in which

[0071] X, Y represent O,

[0072] Z represents -(CH 2 ) m -CR 2 R 3 -(CH 2 ) n -,

[0073] R 2 represents hydrogen or -(CH 2 ) s -O-(CH 2 ) p -SO 3 - M + 、-(CH 2 ) p -SO 3 - M + or -(CH 2 ) s -O-(CH 2 ) p -CHR 4 -SO 3 - M + ,

[0074] R 3 represents -(CH2 ) s -O-(CH 2 ) p -SO 3 - M + 、-(CH 2 ) p -SO 3 - M + or -(CH 2 ) s -O-(CH 2 ) p -CHR 4 -SO 3 - M + ,

[0075] M + represents a cation,

[0076] m and n are the same or different and represent an integer from 0 to 3,

[0077] R 4 represents hydrogen, a methyl group or an ethyl group;

[0078] s represents an integer from 0 to 10, and

[0079] p represents an integer of 1 to 18.

[0080] Very particularly preferred monomers of the formula (IV) are monomers in which

[0081] X, Y represents O,

[0082] Z represents -(CH 2 )-CR 2 R 3 -(CH 2 ) n -,

[0083] R 2 represents hydrogen,

[0084] R 3 Indicates -(CH 2 ) s -O-(CH 2 ) p -SO 3 - M + 、-(CH 2 ) p -SO 3 - M + or -(CH2 ) s -O-(CH 2 ) p -CH(CH 3 )-SO 3 - M + or -(CH 2 ) s -O-(CH 2 ) p -CH(CH 2 CH 3 )-SO 3 - M + ,

[0085] M + represents Na + or K + ,

[0086] n represents 0 or 1,

[0087] s represents 0 or 1, and

[0088] p represents 2, 3, 4 or 5.

[0089] Suitable examples of self-doped polymers are disclosed in WO-A-2014 / 048562 and US-A-2015 / 0337061. Specific examples of very particularly preferred self-doped conductive polymers include poly(4-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]propane-1-sulfonic acid), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-1-sulfonic acid) (PEDOT-S), poly(4-[(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)methoxy]butane-2-sulfonic acid) or mixtures thereof.

[0090] According to a second preferred embodiment of the polythiophene which can be used for forming a conductive polymer layer in process step b1), preferably for forming a solid electrolyte layer in a capacitor, the polythiophene is an externally doped polythiophene which preferably contains monomeric or polymeric counterions to balance the positive charges, which are also referred to hereinafter as polyanions.

[0091] If a solution or dispersion containing a conductive polymer is used to form a conductive polymer layer, polymer anions are preferred over monomer anions because they contribute to film formation and result in a thermally more stable conductive film due to their size. The polymer anions herein can be, for example, anions of polymeric carboxylic acids (such as polyacrylic acid, polymethacrylic acid or polymaleic acid) or polymeric sulfonic acids (such as polystyrene sulfonic acid and polyvinyl sulfonic acid). These polycarboxylic acids and sulfonic acids can also be copolymers of ethylenically carboxylic acids and ethylenically sulfonic acids with other polymerizable monomers (such as acrylates and styrene).

[0092] Preferred polymeric anions in the conjugated polymer b) are anions of polymeric carboxylic acids or sulfonic acids. Particularly preferred polymeric anions are anions of polystyrene sulfonic acid (PSS) or its derivatives.

[0093] The molecular weight of the polyacid providing the polyanion is preferably from 1,000 to 2,000,000, more preferably from 2,000 to 500,000. The polyacid or its alkali metal salts are commercially available, for example polystyrene sulfonic acid and polyacrylic acid, or can be prepared by known processes (see, for example, Houben Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Volume E 20, Makromolekulare Stoffe [Macromolecular Substances], Part 2, (1987), page 1141 et seq.).

[0094] The polymer anion and the conductive polymer can be present in dispersion a), in particular in a weight ratio of 0.5:1 to 50:1, preferably 1:1 to 30:1, more preferably 1.5:1 to 10:1 in dispersion a). The weight of the conductive polymer here corresponds to the initial weight of the monomers used, assuming complete conversion in the polymerization.

[0095] The monomer anions used are, for example, those of C 1 -C 20 -alkanesulfonic acids, such as those of methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid or higher alkanesulfonic acids (such as dodecanesulfonic acid), those of aliphatic perfluorosulfonic acids (such as trifluoromethanesulfonic acid, perfluorobutanesulfonic acid or perfluorooctanesulfonic acid), those of aliphatic C 1 -C 20 -carboxylic acids (such as 2-ethylhexyl carboxylic acid), those of aliphatic perfluorocarboxylic acids (such as trifluoroacetic acid or perfluorooctanoic acid) and optionally C 1 -C 20Those of aromatic sulfonic acids substituted by -alkyl groups (such as benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid or dodecylbenzenesulfonic acid), and those of cycloalkanesulfonic acids (such as camphorsulfonic acid) or tetrafluoroborates, hexafluorophosphates, perchlorates, hexafluoroantimonates, hexafluoroarsenates or hexafluoroantimonates. Preferred monomeric anions are the anions of p-toluenesulfonic acid, methanesulfonic acid or camphorsulfonic acid.

[0096] A very particularly preferred specific example of an externally doped conductive polymer is the complex of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid (PEDOT / PSS).

[0097] To form the solid electrolyte layer, a solution or dispersion containing a conductive polymer such as a PEDOT / PSS-dispersion or a PEDOT-S-solution can be introduced into the electrode body, and then at least part of the solvent or dispersant used to form the solid electrolyte layer is removed. This step can be repeated several times until a solid electrolyte layer of the desired thickness is obtained. In addition, the solid electrolyte layer can also be formed by polymerizing monomers for preparing a conductive polymer such as 3,4-ethylenedioxythiophene in the electrode body in a so-called in-situ polymerization process. It can also be advantageous to use a combination of an externally doped polythiophene (such as PEDOT / PSS) and a self-doped polythiophene (such as PEDOT-S) to form the solid electrolyte layer, as disclosed, for example, in WO-A-2014 / 048562.

[0098] When used in the layer composition for a capacitor, the particles of the solution or dispersion containing the conductive polymer, in particular the particles of the conductive polymer, preferably have a specific conductivity greater than 100 S / cm. In this context, the specific conductivity of the particles is the specific conductivity of the film in the dry state, which is formed from the particles when the solution or dispersion is dried. Preferably, a solution or dispersion is used in which the specific conductivity of the particles is greater than 150 S / cm, particularly preferably greater than 250 S / cm, very particularly preferably greater than 400 S / cm, and extremely particularly preferably greater than 750 S / cm. In some cases, particles with a maximum specific conductivity of 5,000 S / cm are also used.

[0099] In a specific variant of the process according to the invention, the diameter d50 of the particles in the solution or dispersion, in particular the particles of the conductive polymer, is in the range from 1 nm to 100 nm, preferably in the range from 1 nm to less than 70 nm, preferably in the range from 1 nm to 50 nm, particularly preferably in the range from 1 nm to 40 nm, and more particularly preferably in the range from 5 nm to 30 nm. The diameter of the particles is determined by ultracentrifugation measurement. In a preferred variant of the process according to the invention, the d of the diameter distribution of the particles in the solution or dispersion, in particular the particles of the conductive polymer 90The value is preferably less than 150 nm, particularly preferably less than 100 nm, and very particularly preferably less than 50 nm. In a preferred variant of the process according to the invention, the d10 value of the particle size distribution of the particles in the solution or dispersion, in particular the particles of the conductive polymer, is greater than 1 nm, particularly preferably greater than 3 nm, and very particularly preferably greater than 5 nm.

[0100] The particle size of the particles in the dispersion, in particular the particulate conductive polymer, can be reduced, for example, by means of a high-pressure homogenizer. In order to amplify the effect, the operation can also be repeated. In particular, a pressure between 100 bar and 2,000 bar has proven to be advantageous for significantly reducing the particle size. It is also possible to prepare a polythiophene / polyanion complex and subsequently disperse or redisperse it in one or more solvents.

[0101] The solution or dispersion preferably has the purity with respect to metals and transition metals as described on page 6, lines 10 - 29 of the specification WO 2010 / 003874 A2. The great advantage of the low concentration of metals in the dispersion is that when used in capacitors, the dielectric is not damaged during the formation of the solid electrolyte and during the subsequent operation of the capacitor.

[0102] The solution or dispersion of the conductive polymer contains one or more solvents or dispersants. Preferred solvents or dispersants are water, organic solvents, or a mixture of organic solvents and water. Solvents or dispersants that may be mentioned are, for example, the following solvents: aliphatic alcohols such as methanol, ethanol, isopropanol, 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 acetonitrile; aliphatic sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane; aliphatic carboxylic acid amides such as N-methylacetamide, dimethylacetamide, and dimethylformamide; aliphatic and araliphatic ethers such as diethyl ether and anisole. In addition, water or a mixture of water and the above organic solvents can also be used as a solvent or dispersant.

[0103] Preferred solvents and dispersants containing the conductive polymer are water or other protic solvents such as alcohols, for example methanol, ethanol, isopropanol, and butanol, and mixtures of water and these alcohols. Water is a particularly preferred solvent and dispersant.

[0104] In addition, the solution or dispersion containing the conductive polymer may contain additional components, such as surface active substances, for example ionic and non-ionic surfactants, or adhesion promoters, such as for example organofunctional silanes or their hydrolysis products, for example 3-glycidoxypropyltrialkoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane or octyltriethoxysilane; crosslinking agents, such as melamine compounds, blocked isocyanates, functional silanes (for example, tetraethoxysilane), alkoxysilane hydrolysis products (for example, alkoxysilane hydrolysis products based on tetraethoxysilane), epoxy silanes (such as 3-glycidoxypropyltrialkoxysilane-polyurethane), polyacrylates or polyolefin dispersions.

[0105] Preferably, the solution or dispersion containing the conductive polymer contains additional additives that increase the conductivity, such as for example compounds containing an ether group, such as for example 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-methylpyrrolidone (NMP), N-octylpyrrolidone, pyrrolidone; sulfones and sulfoxides, such as for example sulfolane (tetramethylene sulfone), dimethyl sulfoxide (DMSO); sugars or sugar derivatives, such as for example sucrose, glucose, fructose, lactose; sugar alcohols, such as for example sorbitol, mannitol; furan derivatives, such as for example 2-furoic acid, 3-furoic acid; and / or diols or polyols, such as for example ethylene glycol, glycerol, diethylene glycol and triethylene glycol, diglycerol and polyglycerol. Ethylene glycol, dimethyl sulfoxide or polyglycerol are particularly preferably used as additives to increase the conductivity.

[0106] In addition, the solution or dispersion containing the conductive polymer may contain one or more organic binders soluble in organic solvents, as described in WO 2009 / 141209 A1, page 12, lines 16-34. The pH value of the solution or dispersion may be from 1 to 14, and a pH value of from 1 to 8 is preferred. When used in a capacitor, a dispersion with a pH of 2.5 to 8 is preferably used for corrosion-sensitive dielectrics, such as for example alumina or niobium oxide, so that the dielectric is not damaged.

[0107] To adjust the pH, for example, a base or an acid can be added to a solution or dispersion comprising a conductive polymer as described in WO2010 / 003874 A2, page 4, lines 13 - 32. Additives that do not impair the film formation of the dispersion and do not volatilize at higher temperatures (e.g., at the soldering temperature), but remain within the solid electrolyte under these conditions, such as, for example, the bases 2 - dimethylaminoethanol, 2,2'-iminodiethanol or 2,2',2”-nitrilotriethanol and the acid polystyrenesulfonic acid, are preferred.

[0108] The viscosity of the solution or dispersion comprising the conductive polymer can be between 0.1 mPa s and 1,000 mPa s (measured with a rheometer at 20 °C and a shear rate of 100 s-1), depending on the application method. Preferably, the viscosity is from 1 mPa s to 200 mPa s, particularly preferably between 10 mPa s and 150 mPa s, and very particularly preferably from 10 mPa s to 100 mPa s.

[0109] The solids content of the solution or dispersion used in process step b1) is preferably in the range from 1 wt% to 30 wt%, particularly preferably in the range from 1 wt% to 20 wt%, and most particularly preferably in the range from 1 wt% to 10 wt%, in each case based on the total weight of the dispersion. The solids content is determined by drying the dispersion at a temperature high enough to remove the dispersant, but without decomposing the solids thereby.

[0110] After applying the above - mentioned solution or dispersion to the substrate surface, the solvent or dispersion is at least partially removed to form a conductive polymer layer. The at least partial removal is preferably achieved by drying the substrate coated with the conductive polymer solution or dispersion at a temperature in the range from 20 °C to 200 °C, particularly preferably in the range from 50 °C to 175 °C, and most preferably in the range from 80 °C to 150 °C.

[0111] In addition to the above method, the conductive polymer layer in process step b1) can also be prepared in situ on the substrate surface, i.e., by polymerizing a conductive polymer precursor such as an EDOT monomer on the substrate surface. For this purpose, the corresponding monomer and an oxidizing agent are preferably applied to the substrate together or successively. All metal salts known to those skilled in the art that are suitable for the oxidative polymerization of thiophene, aniline or pyrrole can be used as the oxidizing agent. Metal - free oxidizing agents are also suitable, such as inorganic or organic peroxides.

[0112] Suitable metal salts are metal salts of main group or subgroup metals in the periodic table, the latter also being referred to hereinafter as transition metal salts. Suitable transition metal salts are, in particular, inorganic or organic acids or inorganic acids of transition metals containing organic groups such as, for example, salts with iron(III), copper(II), chromium(VI), cerium(IV), manganese(IV), manganese(VII) and ruthenium(III). Preferred transition metal salts are those of iron(III). Very particularly preferred is iron(III) p-toluenesulfonate, iron(III) o-toluenesulfonate or a mixture of iron(III) p-toluenesulfonate and iron(III) o-toluenesulfonate as the metal salt.

[0113] In the case of a capacitor, at least partial removal of the solvent or dispersant leads to the formation of a solid electrolyte layer as the polymer layer prepared in process step b1), which polymer layer completely or partially covers the dielectric. In this context, it is preferred that the coverage of the dielectric by the solid electrolyte is preferably at least 50%, particularly preferably at least 70%, and most preferably at least 80%, which can be determined by measuring the capacitance of the capacitor in the dry and wet states at 120 Hz, as described in DE-A-102005 043 828.

[0114] In process step b1), the application of the solution or dispersion containing the conductive polymer and subsequent removal of at least part of the solvent or dispersant can also be repeated once or several times in order to adapt in this way the thickness of the solid electrolyte layer deposited on the dielectric or the degree of filling of the electrolyte in the anode body to specific requirements.

[0115] In process step b2) of the process according to the invention, a liquid stabilizer phase containing at least one stabilizer and at least one solvent or dispersant is applied to the conductive polymer layer obtained in process step b1) for forming the stabilizer layer, where the at least one stabilizer is gallic acid, a flavonoid or a mixture thereof.

[0116] In a particularly preferred embodiment of the process according to the invention, the stabilizer is a flavonoid. Flavonoids in the sense of the present invention preferably contain a 15-carbon skeleton, which consists of two phenyl rings linked by a 3-carbon linking chain. They are thus also described as C6-C3-C6 compounds. Depending on the chemical structure, degree of oxidation and unsaturation of the linking chain (C3), flavonoids can be divided into different groups. Preferably, such as flavanols, dihydroflavonols, chalcones, anthocyanins, flavonols, aurones, flavones, flavanones and isoflavones.

[0117] Suitable flavonoids that can be used as stabilizers in the process according to the invention include catechin, gallocatechin, epicatechin, taxifolin, isoliquiritigenin, xanthohumol, cyanidin, delphinidin, malvidin, pelargonidin, peonidin, petunidin, morin, quercetin, kaempferol, myricetin, fisetin, aureusidin, luteolin, apigenin, hesperetin, naringenin, eriodictyol, genistein, daidzein and licoricidin, chrysin, galangin, robinetin, gossypetin, among which dihydroflavonols or flavanones are particularly preferably used.

[0118] In a particularly preferred embodiment of the process according to the invention, the flavonoid is selected from the group consisting of dihydroflavonols, flavanones and mixtures thereof, even more preferably the stabilizer is a flavanone, even more preferably the flavanone is selected from the group consisting of hesperetin, naringenin, eriodictyol and mixtures thereof, and most preferably the stabilizer is naringenin (as an enantiomeric mixture (CAS 67604-48-2) or in the form of the pure (S)- or (R)-enantiomer, preferably in the form of the (S)-enantiomer (CAS 480-41-1)):

[0119]

[0120] In a further particularly preferred embodiment of the process according to the invention, the stabilizer is gallic acid.

[0121] In process step b2), the liquid stabilizer phase can be applied to the conductive polymer layer obtained in process step b1) by known processes such as dipping, dip coating, pouring, drop coating, spraying, mist coating, knife coating, brush coating or printing (e.g., inkjet printing, screen printing or pad printing). If used for a capacitor, the application is preferably carried out by immersing the anode body provided in process step b1) into the liquid stabilizer phase and thus impregnating it with the stabilizer. The immersion or impregnation with the stabilizer phase is preferably carried out for a period in the range of 1 second to 120 minutes, particularly preferably in the range of 10 seconds to 60 minutes, and most preferably in the range of 30 seconds to 15 minutes. The application of the liquid stabilizer phase containing the stabilizer to the capacitor body can be facilitated, for example, by increasing or decreasing the pressure, vibration, ultrasound or heat.

[0122] It also depends on the solvent or dispersant used in the liquid stabilizer phase. It is preferred to use the solvents and dispersants included in the above paragraphs for the conductive polymer. This also applies to the liquids mentioned here as preferred. Therefore, it is preferred that the liquid stabilizer phase in process step b2) contains water, ether alcohol or alcohol or mixtures thereof. Generally, the stabilizer and the solvent or dispersant are different from each other.

[0123] All solvents and dispersants known to those skilled in the art can be used as the solvent or dispersant in process step b2), in which the corresponding stabilizer can be dissolved or dispersed, preferably dissolved, and the capacitor body can be impregnated therewith. According to the invention, it is particularly preferred to use water, ether alcohols or alcohols or mixtures thereof as the liquid phase.

[0124] The concentration of the stabilizer in the liquid stabilizer phase used in process step b2) is generally in the range of 0.01% to 99% by weight, preferably in the range of 0.1% to 50% by weight, particularly preferably in the range of 1% to 25% by weight, and most preferably in the range of 2% to 10% by weight, in each case based on the liquid stabilizer phase.

[0125] The liquid stabilizer phase used in process step b2) preferably contains less than 0.5% by weight, preferably less than 0.1% by weight, particularly preferably less than 0.01% by weight and very particularly preferably 0% by weight of conductive polymer, in each case based on the weight of the stabilizer phase. The presence of conductive polymer in the liquid stabilizer phase reduces its storage stability.

[0126] In the process according to the invention, it is preferred that after applying the stabilizer phase in process step b2), at least part of the solvent or dispersant is removed in a further process step b3). Here, it is preferred to remove the solvent or dispersant to an extent of at least 70% by weight, preferably at least 90% by weight, particularly preferably at least 98% by weight, in each case based on the amount of solvent or dispersant employed in process step b2). The solvent or dispersant is generally also almost completely removed. For example, in the case of a capacitor, this removal is preferably carried out by removing the capacitor body comprising the polymer layer from the liquid stabilizer phase and drying it. The drying is preferably carried out at a temperature in the range from 20 °C to 200 °C, particularly preferably in the range from 50 °C to 175 °C, and most preferably in the range from 75 °C to 150 °C for a period in the range from 1 minute to 120 minutes, particularly preferably in the range from 5 minutes to 90 minutes, and most preferably in the range from 10 minutes to 60 minutes. These conditions are also preferred for other layer compositions.

[0127] After forming a stable conductive layer in process step b) of the process according to the invention, the electrolyte capacitor can be completed in a manner known to those skilled in the art. In the case of a tantalum electrolyte capacitor, the capacitor body can be covered, for example, with a graphite layer and a silver layer as known from DE-A-10 2005 043 828, while in the case of an aluminum wound capacitor according to the teachings of US 7,497,879 B2, the capacitor body is incorporated into an aluminum beaker, provided with a sealing inspection glass or rubber, and firmly mechanically closed by crimping. The capacitor can then be aged in a known manner to free it from defects in the dielectric.

[0128] Another contribution to achieving at least one of the objects of the invention is made by the layer composition obtainable by the process according to the invention.

[0129] Another contribution to achieving at least one of the objects of the invention is also made by the layer composition which comprises

[0130] S1. a substrate having a substrate surface;

[0131] S2. a stable conductive polymer layer located after the substrate surface, wherein the stable conductive polymer layer comprises:

[0132] S2a. a conductive polymer layer located after the substrate surface and comprising a conductive polymer, preferably polythiophene;

[0133] S2b. a stabilizer layer located after the conductive polymer layer and comprising at least one stabilizer, wherein the at least one stabilizer is gallic acid, flavonoid or a mixture thereof, preferably flavonoid, more preferably the flavonoid is selected from the group consisting of dihydroflavonol, flavanone and mixtures thereof, even more preferably flavanone, even more preferably the flavanone is selected from the group consisting of hesperetin, naringenin, eriodictyol and mixtures thereof, and most preferably naringenin.

[0134] Herein and generally, regions and in particular layers can follow one another directly or can also be spaced apart by additional layers. In addition, it should be noted that the above statements herein also apply to the layer composition. Preferably, the layer composition is a capacitor. Among them, the polymer layer is located on the anode body.

[0135] The preferred conductive polymers and preferred stabilizers are those conductive polymers and stabilizers which have been described as preferred embodiments in connection with the process for manufacturing the layer composition according to the invention.

[0136] The layer composition according to the invention is particularly suitable for use as an electronic component, in particular as a conductive or antistatic device, as a transparent heating device, as an optional transparent electrode, as a hole injection or hole conducting layer in an organic light emitting diode, for via contacts in circuit boards or as a solid electrolyte in an electrolytic capacitor. They can advantageously be transparent.

[0137] The layer composition according to the invention can be used as an electronic component, for example also on films, on the packaging of electronic components, for decorative films for plastics and for coating screens. In addition, they can also be used as a cathode material in a capacitor, as a transparent electrode in a display, for example as an alternative to an indium tin oxide electrode, or as an electrical conductor in a polymer electronic device. Further possible uses are sensors, batteries, solar cells, electrochromic windows (smart windows) and displays, and corrosion protection.

[0138] The layer composition according to the invention is preferably used in a capacitor. Such capacitors are preferably employed in electronic circuits, for example as filter capacitors or decoupling capacitors. Preferred are such electronic circuits, for example, in a computer (desktop computer, laptop, server); in computer peripherals (such as, for example, PC cards); in portable electronic devices (such as, for example, mobile phones, digital cameras or entertainment electronic devices); in entertainment electronic devices, such as, for example, in CD / DVD players and computer game consoles; in navigation systems; in telecommunications devices; in household appliances; in medical technology, for example in medical technology for defibrillators; in power supplies, such as power supplies based on renewable energy; or in automotive electronics, such as, for example, automotive electronics for hybrid or electric vehicles.

[0139] The invention will now be explained in more detail with reference to the non-limiting drawings and examples.

[0140] Figure 1It is a schematic cross-section of a part of a capacitor as an example of a layer composition according to the present invention. It has an electrode body 1 usually made of a porous electrode material 2 such as tantalum. On the electrode surface 4 of the electrode material 2, a dielectric 3 is formed as a thin layer such that the anode body remains porous and includes the electrode body 1 of the electrode material 2, and the dielectric 3 is formed, and in the context of the layer composition according to the present invention, it can be regarded as a substrate, and the surface of the anode body 4 represents the substrate surface 11 according to the present invention. After the dielectric 3 (optionally after another layer) is a layer of solid electrolyte 5 (for example, a solid electrolyte of PEDOT / PSS particles, an in-situ fabricated PEDOT layer, or a combination thereof), thereby forming a capacitor body 6 including the electrode body 1 of the electrode material 2, the dielectric 3, and the solid electrolyte 5. After the solid electrolyte 5 is a layer 14 of a stabilizer 7, preferably a layer of naringenin, and the solid electrolyte layer 5 and the stabilizer layer 14 together form a stable conductive layer 12. For example, the stabilizer 7 can be introduced into the capacitor body 6 such that it completely or partially fills the pores 8.

[0141] Figure 2 The structure of the layer composition 9 according to the present invention, such as an antistatic film, is shown in a more general form. On a substrate 10, in the case where the antistatic film is usually a PE, PP, or PET layer, there is a conductive polymer layer 13 containing a conductive polymer on its substrate surface 11. On the conductive polymer layer 13, a stabilizer layer 14 having a stabilizer 7, preferably a layer containing naringenin, is formed. The conductive polymer layer 13 and the stabilizer layer 14 together form a stable conductive polymer layer 12.

[0142] Measurement method :

[0143] Surface resistance :

[0144] The surface resistance (SR) of the coating was measured by a four-point measurement method (four-point probe, Mitsubishi Chemical Analytech, Loresta-AX MCP-T370) and expressed in ohms per square. The average value of the surface resistance was obtained by measuring at three different points on the same sample.

[0145] Solid content :

[0146] To determine the solid content, 5 g of the dispersion was dried at 100 °C for 14 hours, and the solid content was determined by the weight difference.

[0147] Capacitance and dissipation factor (DF) :

[0148] The capacitance (in microfarads) and DF (in %) were measured at 20 °C and 120 Hz using an LCR meter (Agilent 4263B).

[0149] Equivalent series resistance (ESR) :

[0150] The ESR (in milliohms) was measured at 20 °C and 100 kHz using an LCR meter (Agilent 4263B).

[0151] Average value :

[0152] Unless otherwise specified herein, the average value is the arithmetic mean. Examples

[0153] Example 1 : Preparation of the stabilizer solution

[0154] 5 g of the corresponding stabilizer (listed in Table 1) and 95 g of ethanol were vigorously mixed in a glass beaker using a stirrer.

[0155] Stabilizer Stabilizer solution 1 Tannic acid Stabilizer solution 2 Propyl gallate Stabilizer solution 3 Naringenin Stabilizer solution 4 Gallic acid Stabilizer solution 5 Myricetin Stabilizer solution 6 Quercetin Stabilizer solution 7 (+)-Taxifolin Stabilizer solution 8 (S)-Hesperetin Stabilizer solution 9 Eriodictyol

[0156] Table 1: Stabilizer solution

[0157] Example 2 : Preparation of the layer by in-situ polymerization on a glass substrate

[0158] A solution was prepared consisting of 1 part by weight of 3,4-ethylenedioxythiophene (CLEVIOS TM M V2, Heraeus Deutschland GmbH & Co. KG) and 10 parts by weight of a 60 wt% ethanol solution of iron(III) p-toluenesulfonate (CLEVIOS TM C-E 60 High Fe, Heraeus Deutschland GmbH & Co. KG) and 5 parts by weight of ethanol.

[0159] This solution was used to coat glass substrates. The glass substrates (5 cm × 20 cm) were immersed in the solution for 1 minute using a dip coater. Thereafter, they were dried at 125 °C for 60 minutes. Subsequently, they were washed with deionized water, then with ethanol, and then continuously immersed in ethanol 3 times, each time for 10 minutes. Finally, they were dried at room temperature for 15 minutes, followed by drying at 125 °C for 60 minutes.

[0160] Then each of the coated glass substrates was immersed in the stabilizer solution of Example 1 for 10 minutes, and thereafter dried at room temperature for 15 minutes, followed by drying at 125 °C for 15 minutes.

[0161] Example 3: Evaluation of Stabilizers

[0162] Then, the coated glass substrates prepared according to Example 2 were subjected to a storage test. The different storage conditions applied were as follows: (A) 85°C, 85% relative humidity; (B) 105°C; (C) 125°C. The storage conditions and storage times applied to each example are listed in Table 2.

[0163] The increase in surface resistance after storage, i.e., the ratio of the surface resistance after storage to the surface resistance before storage (= increase in surface resistance after storage), is listed in Table 2.

[0164] Stabilizer solution Storage conditions Storage time [h] Increase in surface resistance after storage Example 3-1 3 A 164 3 Comparative example 3-1 None A 164 65 Example 3-2 3 A 215 6 Comparative example 3-2 1 A 215 58 Example 3-3 3 C 576 1.5 Comparative example 3-3 None C 576 780 Comparative example 3-4 1 C 576 10 Comparative example 3-5 2 C 576 18 Example 3-4 4 A 145 13 Comparative example 3-6 None A 145 50 Example 3-5 3 C 141 1.4 Example 3-6 4 C 141 2.4 Comparative example 3-7 None C 141 29 Example 3-7 3 B 1,000 1.2 Example 3-8 7 B 1,000 8 Example 3-9 8 B 1,000 3 Example 3-10 9 B 1,000 5 Example 3-11 6 B 1,000 14 Example 3-12 5 B 1,000 13 Comparative example 3-8 None B 1,000 43

[0165] Table 2: Evaluation of Stabilizers

[0166] Example 4 : Preparation of Tantalum Anodes

[0167] Tantalum powder with a specific capacitance of 30,000 μF V / g was pressed into pellets combined with tantalum wires and sintered to form electrode bodies 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 to 60 V to form a dielectric.

[0168] Example 5: Preparation of PEDOT / PSS Dispersion

[0169] A 2 L glass reactor equipped with a stirrer and a thermometer was initially charged with 868 g of deionized water. 330 g of an aqueous solution of polystyrene sulfonic acid with an average molecular weight (weight-average Mw) of 70,000 g / mol and a solids content of 3.8 wt%. The reaction temperature was maintained between 20°C and 25°C. 5.1 g of 3,4-ethylenedioxythiophene was added under stirring. The solution was stirred for 30 minutes. Subsequently, 0.03 g of iron(III) sulfate and 9.5 g of sodium persulfate were added, and the solution was stirred for another 24 hours. After the reaction was completed, 100 ml of a strong acidic cation exchanger (Lewatit S100; Lanxess AG) and 250 ml of a weak basic anion exchanger (Lewatit MP62; Lanxess AG) were added to remove inorganic salts. The solution was stirred for another 2 hours. The ion exchangers were filtered out.

[0170] The PEDOT / PSS dispersion was homogenized ten times at a pressure of 700 bar using a high-pressure homogenizer. Subsequently, the dispersion was concentrated to a solids content of 2.5%, and then homogenized five times at a pressure of 1,500 bar using a high-pressure homogenizer.

[0171] Subsequently, the dispersion was diluted to a solids content of 1.04% and 96 g of the diluted dispersion was mixed with 4 g of dimethyl sulfoxide (DMSO) and stirred vigorously.

[0172] Example 6 : Preparation of PEDOT / PSS Dispersion for Polymer Outer Layer

[0173] A 5L glass reactor equipped with a stirrer and a thermometer was initially charged with 1736 g of deionized water. 660 g of an aqueous solution of polystyrene sulfonic acid with an average molecular weight (weight-average Mw) of 70,000 g / mol and a solids content of 3.8 wt%. The reaction temperature was maintained between 20 °C and 25 °C. 10.2 g of 3,4-ethylenedioxythiophene was added under stirring. The solution was stirred for 30 minutes. Subsequently, 0.06 g of iron(III) sulfate and 19 g of sodium persulfate were added, and the solution was stirred for another 24 hours. After the reaction was completed, 200 ml of a strong acidic cation exchanger (Lewatit S100; Lanxess AG) and 500 ml of a weak basic anion exchanger (Lewatit MP62; Lanxess AG) were added to remove inorganic salts, and the solution was stirred for another 2 hours. The ion exchangers were filtered out. Subsequently, the dispersion was concentrated to a solids content of 1.5%.

[0174] In a beaker equipped with a stirrer, 160 g of this concentrated dispersion, 28 g of deionized water, 6 g of sulfonated polyester (Eastek 1100; solids content 30%; average molecular weight 10,000 g / mol to 15,000 g / mol; Eastman), 8 g of dimethyl sulfoxide, 1 g of 3-glycidoxypropyltrimethoxysilane (Silquest A-187; OSi Specialities), and 0.4 g of wetting agent (Dynol 604; Air Products) were vigorously mixed for 1 hour.

[0175] Example 7 : Preparation of Crosslinking Agent Solution

[0176] 4.0 g of p-toluenesulfonic acid monohydrate, 1.7 g of 1,10-diaminodecane, and 95.5 g of water were vigorously mixed in a glass beaker equipped with a stirrer.

[0177] Example 8 : Preparation of Capacitor with Chemically In-Situ Coated Tantalum Anode

[0178] Prepare a solution consisting of 1 wt% of 3,4-ethylenedioxythiophene (CLEVIOS TM M V2; Heraeus Deutschland GmbH & Co. KG) and 20 wt% of a 40 wt% iron(III) p-toluenesulfonate ethanol solution (CLEVIOS TM C-E; Heraeus Deutschland GmbH & Co. KG).

[0179] This solution is used to impregnate the tantalum anodes of Example 4. The tantalum anodes are immersed in this solution and then exposed to 95% relative atmospheric humidity at room temperature (20 °C) for 30 minutes. Thereafter, they are heat-treated in a drying oven at 50 °C for 15 minutes and at 150 °C for 15 minutes. Then the tantalum anodes are washed in a 2 wt% aqueous solution of p-toluenesulfonic acid for 30 minutes. The tantalum anodes are reformed in a 0.25 wt% aqueous solution of p-toluenesulfonic acid for 30 minutes and then rinsed and dried in distilled water. The above impregnation, drying, temperature treatment, and reformation are repeated four more times. Then the tantalum anodes are immersed in the stabilizer solution of Example 1 for 10 minutes and then dried at room temperature for 15 minutes, followed by drying at 120 °C for 15 minutes.

[0180] Subsequently, it is impregnated into the solution from Example 7 for 1 minute, and then dried at 120 °C for 10 minutes. Thereafter, it is impregnated into the dispersion from Example 6 for 1 minute, and then dried at 120 °C for 10 minutes. Subsequently, it is impregnated into the solution from Example 7 for 1 minute, and then dried at 120 °C for 10 minutes. Thereafter, it is impregnated into the dispersion from Example 6 for 1 minute, and then dried at 120 °C for 10 minutes. Subsequently, it is impregnated into the solution from Example 7 for 1 minute, and then dried at 120 °C for 10 minutes. Thereafter, it is impregnated into the dispersion from Example 6 for 1 minute, and then dried at 120 °C for 10 minutes.

[0181] Then the tantalum anodes are coated with graphite and subsequently coated with a silver layer, and then the tantalum anodes thereby become tantalum capacitors.

[0182] Then the tantalum capacitors are subjected to a storage test (150 °C). The increase in ESR after storage, i.e., the ratio of ESR after storage to ESR before storage, is listed in Table 3.

[0183]

[0184]

[0185] Table 3: Evaluation of Tantalum Capacitors

[0186] Example 9: Preparation of Capacitors with Polymer Dispersions

[0187] The tantalum anodes from Example 4 are impregnated in the dispersion from Example 5 for 1 minute. Then dried at 120 °C for 10 minutes. This sequence of impregnation and drying is carried out nine more times.

[0188] Then the tantalum anodes are immersed in the stabilizer solution of Example 1 for 10 minutes and then dried at room temperature for 15 minutes, followed by drying at 120 °C for 15 minutes.

[0189] Subsequently, it was immersed in the solution from Example 7 for 1 minute, and then dried at 120 °C for 10 minutes. Thereafter, it was immersed in the dispersion from Example 6 for 1 minute, and then dried at 120 °C for 10 minutes. Subsequently, it was immersed in the solution from Example 7 for 1 minute, and then dried at 120 °C for 10 minutes. Thereafter, it was immersed in the dispersion from Example 6 for 1 minute, and then dried at 120 °C for 10 minutes. Subsequently, it was immersed in the solution from Example 7 for 1 minute, and then dried at 120 °C for 10 minutes. Thereafter, it was immersed in the dispersion from Example 6 for 1 minute, and then dried at 120 °C for 10 minutes.

[0190] Then the tantalum anode was coated with graphite and subsequently coated with a silver layer, and then the tantalum anode became a tantalum capacitor.

[0191] Then the tantalum capacitor was subjected to a storage test (85 °C, 85% relative humidity). The increase in ESR after storage, i.e., the ratio of ESR after storage to ESR before storage, is listed in Table 4.

[0192] Stabilizer solution Storage time [h] Increase in ESR after storage Example 9-1 3 182 0.9 Comparative example 9-1 None 182 1.1 Comparative example 9-2 2 182 2.2

[0193] Table 4: Evaluation of tantalum capacitors

[0194] List of reference numerals

[0195] 1 Electrode body

[0196] 2 Electrode material

[0197] 3 Dielectric

[0198] 4 Electrode surface of the anode body

[0199] 5 Solid electrolyte

[0200] 6 Capacitor body

[0201] 7 Stabilizer

[0202] 8 Pores

[0203] 9 Layer composition

[0204] 10 Substrate

[0205] 11 Substrate surface

[0206] 12 Stable conductive polymer layer

[0207] 13 Conductive polymer layer

[0208] 14 Stabilizer layer

Claims

1. A method for manufacturing a layer composition (9), comprising the following method steps: a) Providing a substrate (10) having a substrate surface (11); b) Forming a stable conductive polymer layer (12) on at least a part of the substrate surface (11), the formation of the stable conductive polymer layer (12) comprising the following method steps: b1) Forming a conductive polymer layer (13) containing a conductive polymer on at least a part of the substrate surface (11), wherein the conductive polymer comprises polythiophene; b2) Applying a liquid stabilizer phase containing at least one stabilizer (7) and at least one solvent or dispersant to the conductive polymer layer (13) obtained in method step b1) for the formation of the stabilizer layer (14), wherein the at least one stabilizer (7) is a flavonoid selected from the group consisting of dihydroflavonols, flavanones, and mixtures thereof.

2. The method according to claim 1, wherein in method step b), the conductive polymer layer (13) is formed in situ on the substrate surface (11).

3. The method according to claim 1 or 2, wherein after applying the liquid stabilizer phase in method step b2), at least part of the solvent or dispersant is removed in a further method step b3).

4. The method according to claim 1 or 2, wherein the stabilizer (7) is a flavanone.

5. The method according to claim 4, wherein the stabilizer (7) is naringenin.

6. The method according to claim 1 or 2, wherein the substrate (11) comprises an electrode body (1) of electrode material (2), and a dielectric (3) at least partially covers the surface (4) of this electrode material (2).

7. A layer composition (9) obtainable by the method according to claim 1 or 2.

8. A layer composition (9), comprising S1. A substrate (10) having a substrate surface (11); S2. A stable conductive polymer layer (12) located after the substrate surface (11), wherein the stable conductive polymer layer (12) comprises: S2a. A conductive polymer layer (13) located after the substrate surface (11) and containing a conductive polymer, wherein the conductive polymer comprises polythiophene; S2b. A stabilizer layer (14) located after the conductive polymer layer (13) and containing at least one stabilizer (7), wherein the at least one stabilizer (7) is a flavonoid selected from the group consisting of dihydroflavonols, flavanones, and mixtures thereof.

9. The layer composition (9) according to claim 8, wherein the stabilizer (7) is a flavanone.

10. The layer composition (9) according to claim 9, wherein the stabilizer (7) is naringenin.

11. Use of the layer composition (9) according to any one of claims 7 to 10 as a conductive or antistatic device.

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