Method for manufacturing a dielectric for capacitors and method for manufacturing capacitors and capacitors

Abstract

Method for producing a dielectric for a capacitor, method for producing a capacitor and capacitor The present application relates to a method for producing a dielectric for a capacitor, a method for producing a capacitor, and a capacitor. The method includes the production of a polymer chain from a monomer by polymerization. In this method, some repeat units in the polymer chain are functionalized with a reactive group. The reactive groups are branched from each polymer chain. Furthermore, the reactive groups are suitable for reacting with a linker molecule. The reactive groups are thus suitable for forming a covalent bond with the linker molecule. As a further method step, linker molecules are added to the polymer chain, each linker molecule having at least two chemical connection points, each of which is suitable for forming a covalent bond with a reactive group. Finally, cross-linking of the polymer chain is achieved by reaction of the linker molecules having two reactive groups.

Description

Detailed description of the invention

[0001] This invention relates to a device, a method for manufacturing a dielectric for a capacitor, a method for manufacturing a capacitor, and a capacitor.

[0002] Polymer dielectrics or polymer-containing dielectrics are used in a wide range of power electronics applications, particularly in passive components such as electrical capacitors. Due to increasingly stringent operating environment requirements, for example, the higher integration density of applications, polymers are required to withstand operating temperatures above 150°C. Furthermore, dielectric properties need to be continuously improved, but they also need to be precisely tunable to meet specific technical requirements.

[0003] In the field of organic field-effect transistors, polyacrylate-containing copolymers were proposed as gate insulators in Non-Patent Document 1 below. In particular, it is disclosed that the material can be crosslinked using reactive side groups that directly crosslink one polymer main chain with another. Advantageous dielectric strength was reported.

[0004] [Non-Patent Literature 1] Wentao Xu, Shi-Woo Rhee, Hysteresis-free organic field-effect transistors with high dielectric strength cross-linked polyacrylate copolymer as a gate insulator, Organic Electronics, Vol. 11, Vol. 5, 2010, pp. 836-845, ISSN 1566-1199

[0005] The present invention can at least partially solve the above-mentioned problems. In particular, it can achieve a flexible and adaptable system. Specifically, the problem can at least partially be solved by the subject matter of claim 1. Further objects or preferred embodiments can be found in further claims.

[0006] According to a first aspect, a method for manufacturing a dielectric for capacitors is disclosed. The method includes the step of preparing polymer chains having reactive groups branching from each polymer chain. The reactive groups are suitable for forming covalent bonds with linker molecules. In a further method step, linker molecules are added to the polymer chains, each linker molecule having at least two chemical linkages, each of which is suitable for forming covalent bonds with a reactive group. Finally, crosslinking is performed between or within polymer chains by reaction or covalent bonding between the linker molecules and the two reactive groups.

[0007] In this method, it is preferable that the preparation of the polymer chain is the first step. Subsequently, it is preferable that the linker molecule is added. It is even more preferable that the crosslinking is performed after the two steps described above.

[0008] Polymer chains may be understood here and below as the polymer backbone of a polymer material. As emphasized by the term “polymer backbone,” polymer chains are preferably structurally distinct from crosslinking and branching within or between polymer chains. Polymer chains are preferably significantly longer than such structures. Such polymer chains generally have repeating units. Polymer chains are preferably formed from monomers by polymerization. Monomers are preferably organic molecules. This can be part of the steps to prepare the polymer chain. Monomers are preferably molecules, and more preferably organic molecules. Structural units within the polymer chain resulting from monomers after polymerization are sometimes called repeating units. However, it should be noted that the term repeating units does not imply that periodicity must exist in the polymer chain. Periodicity is often absent, especially in copolymers or terpolymers formed from different monomers. The order or arrangement of interrelated repeating units within the polymer chain is not generally limited. Preferably, it follows a normal distribution. This can be obtained, for example, when a mixture of monomers is polymerized together, which may not be technically complex and is therefore preferable. It should also be noted that the term "repeating unit" does not exclude periodicity, either locally or throughout the entire polymer chain. For example, homopolymers exhibit periodicity. Block copolymers or block terpolymers can also be used. These can, for example, exhibit periodicity within the block.

[0009] It is preferable that the reactive groups are each located on the repeating unit. One or more reactive groups can be covalently bonded to the repeating unit as, for example, one or more functional groups. Therefore, it is possible to refer to a repeating unit having reactive groups.

[0010] A crosslinked material having or made of crosslinked polymer chains can be called a crosslinked polymer or a crosslinked polymer material.

[0011] Polymer chains can have branching. In particular, reactive groups branching from the polymer backbone exhibit a preferred type of branching. It is even more preferable that the branched groups are shorter in length compared to the polymer chain. Branched groups preferably have 100 atoms or less, and more preferably 20 atoms or less.

[0012] A small percentage of cross-connections may already exist between or within polymer chains before cross-linking, which can be created, for example, by the initial polymerization reaction. However, such a degree of cross-linking is preferably lower than that mediated by reactive groups and linker molecules. Preferably, the percentage of polymer chains already cross-linked before cross-linking is such that the polymer chains remain soluble in a solvent, preferably an organic solvent, before cross-linking. Preferably, the percentage of such cross-connections between polymer chains is, for example, 1% or less relative to the number of repeating units in the polymer chain. This can promote solubility.

[0013] Reactive groups are understood as functional groups on a polymer chain that can form covalent bonds through chemical reactions with linker molecules.

[0014] In principle, at least two reactive groups can react with the linker molecule during crosslinking. In this way, two polymer chains can be covalently bonded or linked to each other. Similarly, regions of one chain can also be linked together. The latter is particularly common in the case of long, for example, folded polymer chains. It is preferable that multiple covalent bonds are formed during crosslinking. In particular, it is preferable that multiple reactions occur during crosslinking, and in each of these, a linker molecule having at least two reactive groups forms a covalent bond.

[0015] According to the method described above, it is preferable that at least some repeating units in the polymer chain are functionalized with reactive groups. Functionalization can be carried out at the monomer, i.e., before polymerization, or at the repeating units in the polymer chain, i.e., after polymerization. In principle, it is also possible that all repeating units in the polymer chain are functionalized with reactive groups. In some cases, copolymers or terpolymers are preferred in which some repeating units are not functionalized with reactive groups in addition to repeating units functionalized with reactive groups. "Repeating units not functionalized with reactive groups," or similarly, "monomers not functionalized with reactive groups," can be called "repeating units without reactive groups" or "monomers without reactive groups." In some cases, non-covalent reactive groups, i.e., reactive groups remaining in the crosslinked polymer, may be hygroscopic or react with moisture or water molecules. This can alter the material properties and thus adversely affect the moisture resistance or humidity stability of the dielectric. Therefore, the proportion of repeating units without reactive groups or repeating units preferably having hydrophobic or nonpolar groups can be used as a means to improve the moisture resistance of the dielectric.

[0016] In principle, according to the present invention, two or more reactive groups may be arranged in a repeating unit having reactive groups. In such cases, it is particularly preferable that the directions of the reactive groups branching from the main chain are different. For example, such groups may be arranged on opposite sides of the polymer chain. However, it is particularly preferable that each repeating unit having reactive groups has only one reactive group. This is preferable because the linkage points can be distributed more evenly across the polymer chain than when a small number of repeating units have a large number of reactive groups. In this way, highly aggregated junctions can be avoided. In this way, a more uniform polymer material can be obtained.

[0017] A first control option for the overall degree of crosslinking (absolute degree of crosslinking) of the dielectric can be obtained through the proportion of reactive groups in the entire polymer chain, or through the proportion of repeating units having one reactive group.

[0018] Another way to control the overall degree of crosslinking is by adding linker molecules. The maximum possible absolute degree of crosslinking for one or more polymer chains can be defined by the number of reactive groups. The degree of crosslinking can be set by the amount of linker molecules, as long as there is enough linker molecule to react with or covalently bond with all the reactive groups present, even in large quantities.

[0019] The relative degree of crosslinking can be defined here. The relative degree of crosslinking is the proportion of reactive groups that are covalently bonded to or will covalently bonded to the linker molecule. In other words, the relative degree of crosslinking is the ratio of the number of reactive groups covalently bonded to the linker molecule to the total number of reactive groups present before the crosslinking step. As an alternative to the total number of reactive groups present before the crosslinking step, the sum of the number of reactive groups that are not covalently bonded to the linker molecule after crosslinking and the number of reactive groups that are covalently bonded to the linker molecule can be used as the denominator of the formula. Furthermore, the absolute degree of crosslinking can be defined. The absolute degree of crosslinking is the proportion of crosslinks per repeating unit of the polymer chain. It should be noted that repeating units functionalized with several reactive groups may result in several crosslinks. Therefore, in this case, two or more crosslinks per repeating unit may be included in the absolute degree of crosslinking.

[0020] The linking points on the linker molecule are preferably functional groups on the linker molecule that are suitable for forming a covalent bond with at least one reactive group. The formation of such a bond is sometimes referred to as a crosslinking reaction in relation to the method. In principle, single or multiple bonds can be formed. Multiple bonds are also included as only one bond in the degree of crosslinking defined above.

[0021] The linking points of a linker molecule are preferably spatially separated from each other. For example, two linking points can bond to two different atoms of the linker molecule. In principle, a linking point can form covalent bonds with multiple reactive groups. It should be noted that such multiple linkages are included in the absolute degree of bridging along with the number of covalent bonds formed.

[0022] The inventors of the present invention have discovered that the temperature stability of polymer dielectrics can be set through relative and absolute crosslinking. Therefore, polymer dielectrics produced by the method according to the present invention can have high temperature stability. In particular, this temperature stability can enable the dielectric to be used at temperatures above 150°C. Furthermore, it has been recognized that the temperature stability of the dissipation rate and the level of relative permittivity, also known as dielectric constant, can be influenced or regulated through relative and absolute crosslinking. Dielectrics with a relative permittivity of 3.0 or higher can be obtained.

[0023] For example, if the reactive groups involved in a crosslinking reaction are converted into a more temperature-stable analog by the crosslinking reaction, a degree of absolute crosslinking that is too low can result in poor temperature stability, so simple and precise adjustment of both degrees of crosslinking is important here. However, if the degree of absolute crosslinking is too high, the dielectric or dielectric polymer material may become brittle, meaning it cannot withstand mechanical stress well.

[0024] Since two components, namely a polymer having a reactive group and a linker molecule, are involved in the crosslinking method according to the present invention, this can be called a two-component system. Adjusting the absolute degree of crosslinking can be performed more precisely and more easily in the large-scale overall method using two components than in a one-component system. In a one-component system, for example, only one reactive group is provided on the polymer and directly crosslinks with another reactive group or polymer chain. Consequently, the method according to the present invention, being a two-component system, may have the advantage of higher fault tolerance in individual method steps than the method described in Non-Patent Document 1, which describes a one-component system. For example, the method according to the present invention has broad fault tolerance with respect to the proportion of reactive groups or the proportion of repeating units functionalized with reactive groups. The final degree of crosslinking can be precisely adjusted by the amount of linker molecule added, which can be done without significant technical effort. The basic properties of the dielectric can be clearly defined by the selection of monomers, and these properties can be fine-tuned by the selection of linker molecules.

[0025] Furthermore, the inventors of the present invention recognize that the dielectric properties of a material may be influenced or regulated by the selection of reactive groups and linker molecules, or by the resulting bridging covalent units. In particular, the inventors recognize that the relative permittivity may increase as the relative and absolute degree of bridging increases.

[0026] As described above, some of the reactive groups may remain unreacted. The inventors of the present invention have found that the reacted reactive groups and the unreacted reactive groups have different effects on the dielectric properties of the dielectric. In particular, the reacted reactive groups, i.e., the establishment of crosslinking, can improve the temperature stability and the loss factor. The relative permittivity can be increased by using the remaining unreacted reactive groups. Therefore, the inventors of the present invention recognize that in many cases, it may be more advantageous to leave a proportion of unreacted reactive groups in the dielectric in order to adjust the dielectric properties of the material, particularly to increase the relative permittivity. This has the advantage that the same type of functional group can be used on the polymer chain to generate crosslinking, where the exact proportion of the reacted and unreacted groups is set via the linker molecule and can also define the dielectric properties. In this way, it is possible to avoid complex functionalization with different functional groups, some of which are involved in setting the crosslinking and others in setting the dielectric properties. According to such a method, it is preferable that the proportion of unreacted linker molecules is low, preferably zero, within the technically feasible range.

[0027] According to a preferred embodiment, the proportion of repeating units containing reactive groups relative to all repeating units is 20% to 100%.

[0028] The relative and absolute degrees of crosslinking can be advantageously adjusted via the above-mentioned proportion of repeating units in the polymer chain having reactive groups in order to ensure sufficient temperature stability and to adjust the dielectric properties. The proportion defined above is particularly preferred when only one such group is bonded to the repeating unit having a reactive group. The proportion of repeating units having reactive groups is particularly preferably 40% and 70%. Here, the above-mentioned effects are particularly remarkable.

[0029] In a further preferred embodiment, the proportion of reactive groups covalently bonded to or becoming covalently bonded to the linker molecule may be 25% to 99%. Therefore, the relative degree of crosslinking may be 25% to 99%. It has been found that this relative degree of crosslinking can be advantageous for both dielectric properties and temperature stability. In particular, it has been found that the proportion of repeating units having the reactive groups defined above, together with the relative degree of crosslinking disclosed herein, facilitates the achievement of temperature stability above 150°C.

[0030] To improve stability and dielectric properties at high temperatures, a relative crosslinking degree of 70% to 99% is particularly preferable. A relative crosslinking degree of 95% to 99% is even more preferable. The technical effects are particularly significant when the range is preferred or even more preferred.

[0031] Furthermore, the absolute degree of crosslinking, i.e., the ratio of covalent compounds per total number of repeating units, is preferably set to 5% to 99%. More preferably, the absolute degree of crosslinking is 18% to 60%. Even more preferably, the absolute degree of crosslinking is 40% to 60%. This allows the above-mentioned goals to be achieved even better. This range is particularly preferred when there is only one such group in the repeating unit having a reactive group.

[0032] This method is preferable in which at least a portion of the repeating units having reactive groups are acrylate repeating units or acrylate-based repeating units. Preferably, the reactive groups can be bonded to the acrylate repeating units or acrylate-based repeating units via ester bonds using acrylate functional groups, or similarly via amide bonds.

[0033] It is preferable that the polymer chain is formed of acrylate monomers. Polymerization converts the acrylate monomers into acrylate repeating units in the polymer chain. A preferred method here is radical polymerization.

[0034] Reactive groups can be bonded via ester bonds. Therefore, monomers, or repeating units having reactive groups, may include acrylate monomers or acrylate repeating units. More preferably, all repeating units having reactive groups are acrylate repeating units.

[0035] The inventors of the present invention have found that polymer chains or copolymer chains containing acrylate repeating units are particularly well-suited for functionalization using reactive groups because they can be easily chemically bonded via ester bonds.

[0036] In a preferred embodiment, the reactive group comprises an epoxide, where the linker molecule comprises a functional group suitable for reacting with the epoxide. Particularly and preferably, the functional group can be selected from carboxylic acids, amines, alcohols, and anhydrides.

[0037] Preferably, the epoxy is the terminal group. In other words, it is preferable that the epoxy oxygen crosslinks the terminal carbon atom with an adjacent carbon atom. This has the advantage that the epoxy group is easily sterically approached and contributes to an efficient crosslinking reaction. For example, the epoxy may be a glycidyl group. It is preferable that the glycidyl group be introduced into the polymer chain in the form of a glycidyl methacrylate monomer as a homopolymer or copolymer. The glycidyl methacrylate repeating unit can be used in the polymerized polymer chain.

[0038] Crosslinking can be easily achieved by reacting the epoxide with the aforementioned groups. In this case, "easily" specifically means that a stoichiometrically complete crosslinking reaction can be achieved by gentle heating between 30°C and 150°C. The absolute and relative degree of crosslinking can therefore be precisely controlled.

[0039] When using epoxides as reactive groups, the values ​​given above are particularly preferred for the proportion of monomers or repeating units having reactive groups, and for the relative degree of crosslinking.

[0040] In principle, two-component crosslinking can also be carried out in the so-called grafting-from form. This is particularly possible in relation to the use of epoxides. In particular, reactive groups on polymer chains can be used to link two chains together through a reaction that can usually function as a polymerization reaction. In particular, some small molecules can form oligomeric or polymeric structures starting from one reactive group toward another reactive group on another polymer chain. Alternatively, compounds within the chain can be generated by the same type of reaction. For example, terminal epoxide groups can react with epoxide monomers such as ethylene oxide, propylene oxide, or epoxybutane after cationic initiation.

[0041] According to another preferred embodiment, crosslinking, i.e., the formation of at least several covalent bonds between the reactive group and the linking point, N 1 or S N It can occur via two reactions, or such reactions may be involved.

[0042] S N 1 or S N The term "2-reaction" is used here to encompass all reactions, and in particular, to include reactions of carboxylic acid halides that proceed according to an addition-elimination mechanism in which a leaving group is involved and a nucleophile can attack the carbon atom from which the leaving group has left or which will leave during the process.

[0043] Preferably, the reactive group has a leaving group. The linker molecule preferably contains a nucleophilic site or a nucleophilic functional group as a linking point.

[0044] Examples of leaving groups include halogens on carbon atoms, but also oxygen atoms in epoxides. For example, amines or alcohols can act as nucleophiles. Alternatively, carboxylic acid halides can also be used. This is particularly preferred in the field of grafting-from reactions.

[0045] In a more preferred embodiment, Markovnikov addition or inverse Markovnikov addition may be involved in the bridging. Inverse Markovnikov addition is preferred.

[0046] A particularly preferred example of reverse Markovnikov addition is the thiol-enclick reaction of a carbon-carbon double bond between a thiol and an alkene, forming a thioether. In the case of the thiol-enclick reaction, it is preferable that the reactive group is a thiol and the linker molecule has a carbon-carbon double bond as a linking site, or that the linker molecule has a thiol group as a linking site and the carbon-carbon double bond represents the reactive group.

[0047] In principle, numerous different reactive groups and linker molecules can be used for the methods according to the present invention, and they can also coexist in situ. In principle, linker molecules can also have chemically different linking points. This is even preferable in some cases and can be used to adjust dielectric properties. However, it is preferable that all linking points can form covalent bonds with all reactive groups present in situ under similar or identical reaction conditions. This means that various conditions for crosslinking in the method can be avoided and the method can be made technically simple. Furthermore, it is even more preferable that only a single type of reactive group is present in situ and only a single type of linking point is attached. This is preferable to avoid unexpected side reactions and to keep the composition simple in particular. For example, epoxides can be used as reactive groups. It is also possible that only epoxides are used. Epoxides can also be part of different functional groups. Thus, it is possible that only a single type of linking point is present in situ, for example, exclusively amines, or instead exclusively carboxylic acids, may be present as linking points. However, the linker molecules may be different.

[0048] As explained above, even with a simple system using only one type of reactive group and one type of linker molecule, the degree of crosslinking, dielectric properties, and temperature stability can be well controlled.

[0049] In a preferred embodiment, the method includes a step of depositing or reaction extrusion from a solution.

[0050] Therefore, in this procedure, the dielectric can be formed by deposition from a solution or using deposition from a solution, or by reactive extrusion or using reactive extrusion.

[0051] The method according to the present invention is highly flexible and can therefore be applied to or adapted to both of these separation methods.

[0052] Deposition from a solution can be performed before crosslinking. For example, a solution containing polymer chains and linker molecules can be deposited onto a substrate or a first electrode. Crosslinking can be performed after deposition.

[0053] It is generally preferable that the dielectric material be formed as a layer, that is, as a dielectric layer.

[0054] In particular, homopolymers or copolymers having acrylate repeating units are preferred in order to enable the production of dielectrics using both deposition from solution and reaction extrusion. Here, copolymers are especially preferred.

[0055] This can be seen as an advantage over the commonly used biaxially oriented polypropylene BOPP, which is typically manufactured solely through calendering.

[0056] In a more preferred embodiment of this method, the polymer chain is a copolymer comprising acrylate repeating units and repeating units having nonpolar or unsaturated hydrocarbon groups. The proportion of acrylate repeating units is preferably 20 to 80%. More preferably, the proportion of acrylate repeating units in the corresponding copolymer may be 40 to 60%. Even more preferably, such a proportion may be 45 to 55%.

[0057] In copolymers, acrylate repeating units have the advantages described above. Water absorption can be reduced or moisture resistance can be improved through the proportion of repeating units having nonpolar or unsaturated hydrocarbon groups.

[0058] In a further preferred embodiment, crosslinking can be carried out by annealing at a temperature suitable for inducing the crosslinking reaction. Furthermore, it is preferable that the temperature is suitable for the crosslinking reaction to occur up to 99% of the components selected from the reactive groups and linker molecules that are present in a low proportion with respect to the reaction equivalent.

[0059] In other words, in relation to a complete reaction, either the proportion of reactive groups or the proportion of linker molecules is present in a small amount. Preferably, the proportion of linker molecules is present in a smaller amount. The annealing temperature must be suitable for producing at least a 99% complete reaction in relation to the small number of components. More preferably, the annealing temperature is suitable for producing a stoichiometrically complete reaction within the range that is technically feasible.

[0060] Cross-linking involving the formation of covalent bonds is technically possible with minimal effort through annealing.

[0061] In a further embodiment, a method for manufacturing a capacitor is disclosed. The method for manufacturing a capacitor includes the step of manufacturing a dielectric according to the method described above. Furthermore, the method includes the step of creating a dielectric layer using or from a dielectric. Furthermore, electrodes are mounted on one side of the layer. Electrodes may also be mounted on both sides of the layer. A technically functional capacitor has two electrodes, but only one of them needs to be in direct contact with the dielectric layer.

[0062] In many embodiments, it is preferable that both electrodes are in direct contact with the dielectric layer. In this case, it is often preferable that the first electrode sandwiches the dielectric layer.

[0063] Preferably, the dielectric is formed as a dielectric layer, for example, using the method described above.

[0064] A method for capacitors and a capacitor manufactured using the same have the same advantages as described above with respect to a method for manufacturing a dielectric for capacitors.

[0065] Attaching electrodes to one side of the dielectric layer may preferably mean that the electrodes are applied directly to the layer.

[0066] Preferably, the entire dielectric consists solely of a crosslinked polymer material, with the exception of technically unavoidable impurities such as radical starters or similar residues.

[0067] In a further preferred embodiment, a capacitor is provided. Preferably, the dielectric layer of the capacitor can be produced by the method described above. Even more preferably, the capacitor can be manufactured by the method described above.

[0068] A capacitor has at least one electrode located in a dielectric layer. Alternatively, two electrodes may be located on both sides of the dielectric layer. The dielectric layer has a polymer material in which polymer main chains are covalently linked to each other or to themselves via crosslinking linker molecules.

[0069] Since the capacitor is preferably manufactured using the method described above, the polymer backbone is preferably defined in a crosslinked polymer material having or comprising repeating units formed from monomers as constituent elements. The polymer backbone preferably has side groups branching from the polymer backbone, which form crosslinks to another polymer backbone or to another point on the same polymer backbone. The branching side groups preferably include at least one reacted reactive group, a reacted linker molecule bonded thereto, and further reactive groups located at different sites on the reacted linker molecule. Particularly preferably, here the linker molecule corresponds to the linker molecule described above. Furthermore, the functional groups to which the linker molecule in the polymer material is bonded are preferably the reactive groups described above.

[0070] Preferably, the capacitor according to the present invention may also have unreacted reactive groups in addition to the reacted reactive groups. This has the advantages described above.

[0071] In a preferred embodiment, the proportion of repeating units covalently bonded to the linker molecule is between 5% and 99%. This is the absolute degree of crosslinking as defined above.

[0072] The absolute degree of crosslinking is preferably 18% to 60%, and more preferably 40% to 60%.

[0073] Within the absolute degree of bridging within the range described above, good temperature stability can be achieved, enabling the capacitor to operate at temperatures above 150°C.

[0074] In a preferred embodiment, the polymer backbone comprises acrylate repeating units covalently bonded to a linker molecule, or functional groups suitable for such bonding are bonded to the acrylate repeating units via ester bonds.

[0075] Therefore, the polymer chain may be a homopolymer or copolymer containing acrylate repeating units.

[0076] Functional groups suitable for crosslinking preferably include both reacted and unreacted reactive groups. As described above, the acrylate repeating unit has the advantage that the ester group enables the bonding of functional groups suitable for crosslinking, i.e., reactive groups in the sense of the method described above.

[0077] In a further preferred embodiment, the ratio of repeating units covalently linked to the linker molecule via functional groups to the total of these repeating units and repeating units having functional groups suitable for covalent linkage to the linker molecule is 25% to 99%.

[0078] As explained above, this can correspond to a relative degree of crosslinking when each repeating unit having a reactive group has only one such group. This results in the advantages described above. These advantages are particularly evident when acrylate repeating units having reactive groups or linking functional groups are included.

[0079] In a further preferred embodiment, the covalent compound or the covalently linked functional group is selected from ether crosslinks, ester crosslinks, amine crosslinks, amide crosslinks, and thioether crosslinks.

[0080] These covalently bonded bridges preferably correspond to the covalent bonds formed by the method described above. This brings about corresponding advantages.

[0081] In another preferred embodiment, the capacitor is a multilayer component. This multilayer component includes a number of electrodes stacked alternately with dielectric layers. These electrodes are preferably in contact via external electrodes. The stacking direction can be defined in the multilayer component. The layers of the multilayer component are preferably arranged perpendicular to the stacking direction.

[0082] It is preferable that multilayer components can be used as so-called SMD components (surface mount devices).

[0083] In another preferred embodiment, the capacitor is a wound-type capacitor. Preferably, the wound-type capacitor has only two first electrodes with a dielectric layer sandwiched between them. This sandwich-like structure is wound to form a capacitor roll.

[0084] In a further embodiment, the use of the above-described materials in dielectrics is also described. Furthermore, the use of dielectrics in capacitors is also described. In this case, the dielectric has the above-described characteristics or is manufactured using the above-described method.

[0085] The present invention will be described in more detail below with reference to the figures. The figures include representations of both chemical reactions and components. In particular, the components are not shown to scale. The size of the components may be distorted. Lengths or length ratios cannot be determined from the drawings. [Brief explanation of the drawing]

[0086] [Figure 1] This is a diagram showing a capacitor. [Figure 2] This diagram schematically illustrates various common crosslinking patterns in polymers. [Figure 3] This figure shows the general formula of an acrylate monomer. [Figure 4] This figure shows a typical representation of copolymers containing acrylate repeating units. [Figure 5] This is a diagram showing radical polymerization. [Figure 6] This diagram shows a side reaction of radical polymerization. [Figure 7] This is a diagram showing the first crosslinking reaction. [Figure 8] This figure shows the second crosslinking reaction. [Figure 9] This diagram schematically illustrates the third crosslinking reaction. [Figure 10] This diagram schematically illustrates the fourth crosslinking reaction. [Figure 11] This diagram schematically illustrates the fifth crosslinking reaction. [Figure 12]This diagram schematically illustrates the sixth crosslinking reaction. [Figure 13] This diagram schematically illustrates the seventh crosslinking reaction. [Figure 14] This is a diagram showing the process for manufacturing a capacitor. [Figure 15] This is a diagram showing the first thermogravimetric analysis. [Figure 16] This is a diagram showing the second thermogravimetric analysis. [Figure 17] This figure shows the dependence of the loss coefficient on the degree of bridging. [Figure 18] This figure shows the dependence of the dielectric constant on the degree of bridging. [Figure 19] This figure shows the breakdown voltage distribution of the system according to the present invention. [Figure 20] This figure shows a first example of a multilayer capacitor. [Figure 21] This figure shows a second example of a multilayer capacitor. [Figure 22] This figure shows a third example of a multilayer capacitor. [Figure 23] This figure shows a fourth example of a multilayer capacitor. [Figure 24] This is a diagram showing a cross-sectional view of a wound-type capacitor. [Modes for carrying out the invention]

[0087] Figure 1 shows a schematic diagram of a simple capacitor 1, which may be, for example, a plate capacitor. Capacitor 1 has a first electrode 3 and a second electrode 4. A dielectric layer 2 is located between the first electrode 3 and the second electrode 4. The dielectric layer 2 has a dielectric, or a polymer dielectric made of a polymer material manufactured according to the method of the present invention. The polymer material may, for example, be included in a layer in the dielectric 2, or this layer may consist of a polymer material (neither shown). Furthermore, the material of the dielectric layer 2 may include a mixed material of the polymer material according to the present invention and other polymers. Preferably, the dielectric layer 2 consists only of the crosslinked polymer material according to the present invention. Here, "consists only of" means that it contains only the material according to the present invention, but technically unavoidable impurities such as solvent residues or radical initiators may also be included in the material. Preferably, the proportion of technically unavoidable impurities is less than 1%.

[0088] Figure 2 shows schematic sketches of three possible polymer states. The image on the left shows an uncrosslinked, branched polymer chain.

[0089] Here, "branched" means that the functional group shown here as a gray oval is branched from the polymer chain or polymer back chain. The polymer back chain does not have crosslinking, nor does it have crosslinking to other polymer chains or within itself.

[0090] The central image shows a polymer chain similar to the image on the left, but here, individual links are also formed via reactive groups, as indicated by the bonding dots. For the purposes of this invention, the bonding dots connecting the ellipses represent linker molecules.

[0091] The image on the right shows a strong degree of crosslinking, indicating that linkage occurs via branched functional groups or reactive groups.

[0092] Figure 3 shows a typical acrylate structure, which is a preferred monomer for the method according to the present invention. The structure shown in Figure 3 has two types of groups, R1 and R2. Furthermore, this structure has a carbon-carbon double bond. Polymerization can occur via the carbon-carbon double bond through the radical chain reaction shown below.

[0093] Group R1 can be any group. In particular, it is preferable that group R1 is a hydrogen or methyl group. Alternatively, one of the following groups may be present in group R1, or R1 may consist of one of the following groups: alkyl group, alkaryl group, heteroalkyl group, heteroaryl group, alkenyl group, halogen or halide, amino group, amide group, carboxylic acid group, ester group, hydroxyl group, ether group, imide group, thiol group, and thioether group.

[0094] Group R2 may have multiple groups. Preferably, the reactive groups are located on group R2 via ester bonds.

[0095] As shown below, it is particularly preferable that the glycidyl group represents group R2. The glycidyl group has a terminal epoxy group. However, in principle, any type of group having an epoxide can be used as group R2. A terminal epoxy group is particularly preferred.

[0096] Linking can occur via epoxy groups, but it can also occur via grafting-from type reactions, or via other suitable groups. In particular, polymerization-type reactions can be used here, which begin with a reactive group of a polymer chain, then form oligomeric or polymeric side chains, which then bond to another polymer chain or another point on the first polymer chain, thus ending the reaction. This reaction is achieved via small molecules that can be called grafting-from monomers. Grafting-from monomers form grafting-from repeating units between two reactive groups. In particular, grafting-from monomers can be selected from ethylene oxide, propylene oxide, or 1,2-epoxybutane.

[0097] Alternatively, residue R2 may contain a halide.

[0098] Furthermore, the entire oxygen R2 motif (O-R2) can be replaced with a halide, thereby allowing the carboxylic acid halide to form a reactive group.

[0099] As a further alternative, the thiol group can be positioned in the polymer chain as or via the functional group R2. As another further alternative, the carbon-carbon double bond can be positioned as a reactive group via the functional group R2. For example, the carbon-carbon double bond may be a terminal double bond.

[0100] Figure 4 shows a copolymer chain. The copolymer chain has an acrylate repeating unit as the first repeating unit, and it is preferable that the acrylate repeating unit is formed from the acrylate monomer shown in Figure 3. The copolymer further contains C as the second repeating unit of the copolymer. The acrylate repeating unit or X can, in principle, be combined in any form of copolymer, such as a block copolymer. In practice, it may be preferable that the repeating units of the copolymer are randomly distributed along the chain. Alternatively, the copolymer may have repeating units arranged periodically. This can be formed, for example, by polymerizing a dimer of a monomer or other pre-formed units. In addition to the example of acrylate-containing copolymers, these concepts can be similarly applied to all kinds of copolymers or terpolymers.

[0101] The acrylate repeating units in Figure 4 can sometimes be seen as placeholders for other monomers.

[0102] X can preferably be selected from linear, branched, or cyclic polysiloxanes, polyolefins, or heteroatom polyolefins. These can also be optionally functionalized with alkaryl groups, alkenyl groups, halogen groups, amino groups, nitrile groups, nitro groups, alcohols, carboxylic acid groups, carboxylic acid ester groups, or thio groups. Acrylate repeating units having nonpolar groups are also particularly preferred for X. Therefore, the polymer or polymer chain is preferably a copolymer of glycidyl methacrylate and acrylate repeating units having nonpolar groups.

[0103] Figure 5 shows an example of a radical chain reaction. The example in Figure 5 illustrates a polymerization reaction in which acrylate monomers are polymerized according to Figure 3. However, this scheme is similarly applicable to any hypothetical radical polymerization.

[0104] Radical initiators, such as organic peroxides, split into two radicals via thermal or photochemical reactions. The organic peroxide can then attack the carbon-carbon double bond of a monomer, such as an acrylate monomer. This then forms another radical, and a chain reaction can continue. The chain reaction is terminated by a termination reaction. Radical polymerization can result in a normally distributed polymer chain length, which can be determined by the average chain length or molecular weight. Furthermore, radical polymerization results in a statistically distributed set of repeating units within the polymer chain for copolymer formation.

[0105] Block copolymers or block terpolymers do not have a statistical distribution of repeating units.

[0106] In the case of the acrylate-containing copolymer according to the present invention, for example, an average mass of 32 kDa (32 kilodaltons if written out in full) can be achieved.

[0107] It is preferable that the polymer chain has only short branches consisting of functional groups branching from the main chain. Branching of the polymer chain, i.e., branching of the polymer main chain, is undesirable.

[0108] As shown in Figure 6, a radical chain reaction can, under certain circumstances, result in two linked or crosslinked polymer chains as a side reaction. According to the present invention, it is preferable that the proportion of the corresponding crosslinking reaction or the proportion of the crosslinked polymer main chain is low. In particular, it is preferable that the degree of crosslinking achieved in this manner is significantly lower than the degree of crosslinking achieved via the crosslinking reaction described later. A degree of crosslinking of less than 1% is preferred, which allows for solubility in organic solvents.

[0109] Figure 7 shows a first example of a crosslinking reaction. This can be considered an example of any crosslinking that occurs using an epoxide (terminal epoxide) as a reactive group and a carboxylic acid-containing linker molecule. Succinic acid is shown here as an example of a carboxylic acid-containing linker molecule, or more particularly as an example of a difunctional carboxylic acid (dicarboxylic acid). Alternatively, and more preferably, oxalic acid, valonic acid, or adipic acid can also be used. The carboxylic acid group or the single-bonded oxygen therein can act as a linking point here. In the case of the linker molecules described above, it is preferable that the linking point is located at the point of the molecule that is furthest away from each other.

[0110] In this reaction, the single-bonded oxygen of the acid group attacks the terminal carbon of the epoxy group using its free pair electrode as a nucleophile. A proton moves to the previously attached epoxy oxygen, forming an ester bond. Alternatively, the acid group can be deprotonated first, and the resulting carboxylate group can attack as a nucleophile.

[0111] It is preferable that the structure formed from the repeating units, linker molecules, and reactive groups can be identified within the polymer chain. After the completion of the crosslinking reaction in which the polymer chain is linked to the linker molecules via two reactive groups, in this example, the original monomers of the polymer, as well as the reactive groups and linker molecules, can be identified even in their reacted forms. While not essential, it is preferable that this be generalized to each reaction according to the present invention.

[0112] The second partial reaction of crosslinking begins with the product of the first partial reaction, and the second carboxylic acid attacks the epoxy group again in a similar manner. This forms a crosslink between two polymer chains, or similarly, within two parts of one polymer chain.

[0113] Figure 8 shows the second reaction or reactants of the second crosslinking reaction that forms the polymer network. Polyglycidyl methacrylate is again shown as representative of all epoxy-functionalized acrylates. The linker molecule shown here is isophorone diamine, which is representative of amine-based linker molecules. Alternatively, and equally preferably, for example, p-xylylenediamine, 1,5-diamino-2-methylpentane, ethylenediamine, and hexamethylenediamine can be used as linker molecules. Alternatively, one of the amine groups can be replaced with an alcohol group. Examples of these may be ethanolamine, diethanolamine, N-benzylethanolamine, 2-amino-2-methylpropionic acid, and 2-aminocyclopentanol.

[0114] According to the reaction mechanism shown in Figure 8, the primary amine acts as a linking site and can attack the terminal carbon of the epoxy group as a nucleophile. This results in crosslinking. In this example, two or more reactive groups can react with the primary amine acting as a linking site. In this example, two adjacent epoxy groups on the polymer chain can each react with an amino group to form a tertiary amine. For this to occur, the reactive groups must be sufficiently close together on the polymer chain. In copolymers with repeating units that do not have reactive groups, this reaction can be suppressed if the repeating units with reactive groups are sufficiently far apart. In such cases, the reaction can only result in the formation of a secondary amine.

[0115] Therefore, the primary amino group in this example is an example of a linkage site that can react with two or more reactive groups.

[0116] Alternatively, a molecule having an alcohol group or a secondary amine as a linking point can be used as the linking molecule.

[0117] Figure 9 shows a third example of the crosslinking reaction. Polyglycidyl methacrylate is again shown as representative of all epoxy-functionalized acrylates. Here, maleic anhydride is shown as an example of a linker molecule. Alternative anhydrides can be selected from, for example, the carboxylic acid anhydrides, phthalic anhydrides, and methylated phthalic anhydrides described in Figure 7.

[0118] Figure 10 shows an example of the fourth crosslinking reaction. The reactants shown are a polyacrylate derivative having a carboxylic acid chloride and isophorone diamine as a linker molecule. The acid chloride group is a reactive group that reacts with the primary amine group of isophorone diamine to form an amide. Alternatively, other suitable leaving groups, such as other halogen-functionalized functional groups, can also be used.

[0119] Isophorone diamines are representative of bifunctional amines as linker molecules. Alternatively, and more preferably, ethylenediamine or hexamethylenediamine can be used, but triamines can also be used. Alternatively, one of the amino groups can be replaced with an alcohol group. Examples of such molecules are ethanolamine, diethanolamine, or 2-aminocyclopentanol.

[0120] The two amino groups of isophoronediamine represent (bifunctional) linkages that attack the acid chloride group.

[0121] Figure 11 shows the fifth crosslinking reaction. The reactants shown are a polyacrylate derivative having a carboxylic acid chloride and ethylene glycol as the linker molecule. Substitutes described in Figure 10 can be used instead of the reactive groups shown. Alternatively, for example, 1,4-butanediol, propylene-1,3-diol, pentaerythritol, or xylitol can be used as the linker molecule. The alcohol group acts as a linking point. The acyl chloride group is a reactive group that reacts with the alcohol group to form an ester.

[0122] Figure 12 shows a sixth example of a crosslinking reaction. The polymer has an amide bond as the point of connection between the side group and the reactive group, where the reactive group is a terminal thiol group.

[0123] A diene containing two carbon-carbon double bonds (alkenyl groups) is used as a linker molecule. The alkenyl groups act as linking points. The thiol group can attack the double bond of an alkene or diaryne by reverse Markovnikov addition, which can occur radically and be initiated thermally or photochemically, or, in this particular case, by a thiol-enclick reaction, thereby forming a thioether.

[0124] Thermal initiators that can be used for this purpose include N,N-azobisisobutyronitrile, dibenzoyl peroxide, dicumyl peroxide, or potassium persulfate. For example, benzoin or ethyl (2,4,6-trimethylbenzoyl)phenyl phosphine can be used as photochemical initiators.

[0125] Examples of unsaturated alkenes that can be used as linker molecules include 1,3-pentadiene, 1,4-pentadiene, isoprene, 2,4-hexadiene, hexa-1,3,5-triene, and 1,3-butadiene.

[0126] Figure 13 shows a seventh example of a crosslinking reaction. Here, the polymer has a double bond as the reactive group. In this example, this is bonded via a carbon-carbon bond rather than via a heteroatom to the chain. Ethylene glycol bis(3-mercaptopropionate) is shown here as the linker molecule for the thiol-enclick reaction as an example of reverse Markovnikov addition. Alternatively, glycol di(3-mercaptopropionate), glycol dimercaptoacetate, trimethylolpropane tri(3-mercaptopropionate), or pentaerythritol tetra(3-mercaptopropionate) can also be used.

[0127] Figure 14 shows a schematic diagram of the capacitor manufacturing method.

[0128] First, electrodes are formed according to step A. In principle, any suitable metal sheet or metal film can be used as an electrode. However, preferably, the electrodes are applied to a substrate. Plastic films such as polyimide films or glass or semiconductor wafers can be used as substrates. A metal layer can be applied to these using an appropriate method. Preferably, the method of physical vapor deposition (PVD) is used here. Examples of PVD are sputtering or thermal evaporation. The first electrode can consist of a single material such as aluminum or silver. Alternatively, multilayer electrodes such as chromium / aluminum, chromium / silver, chromium / nickel / aluminum, or chromium / nickel / silver can be used. The thickness of the electrode layers is on the order of tens of nanometers and has a thickness adapted to each design.

[0129] Next, the dielectric is applied according to step B. In principle, reaction extrusion or deposition from solution can be used for dielectric fabrication. In the method described herein, deposition from solution is preferred. In particular, the polymer solution can be applied via slot die coating, spray coating, or stencil printing. The polymer solution contains polymer chains that are uncrosslinked or very slightly crosslinked. The polymer chains are produced by polymerization of monomers prior to deposition. The polymer chains can be homopolymers or copolymers, each of which contains repeating units having reactive groups. The reactive groups can be bonded to the monomers by functionalization before polymerization or to the repeating units after polymerization. Furthermore, the polymer solution contains a solvent to maintain the polymer in solution. In the case of poly(glycidyl methacrylate) or the corresponding copolymer according to the present invention, ethyl acetate, ethyl lactate, or chloroform can preferably be used as the solvent. The polymer solution can have a polymer concentration of 20 to 500 mg / ml. Further additives may be included. Furthermore, a specified proportion of linker molecules is added to the polymer solution. The amount of linker molecules is determined by the proportion of reactive groups and the degree of crosslinking achieved. The linker molecule has at least two linkage points suitable for reacting with the reactive group. Furthermore, crosslinking of the polymer chain is performed in step B. Depending on the system, crosslinking of the polymer chain is performed in different ways. Thermal crosslinking by annealing at 30-150°C is preferred.

[0130] Next, a second electrode can be applied in step C using the PVD method. In principle, the second electrode can be manufactured or deposited from the same material as the first electrode. To manufacture the capacitor shown in Figure 1, only steps A, B, and C are performed. If there is a possible substrate, it can be removed after step C. Therefore, for a wound capacitor, steps A, B, and C can be performed.

[0131] In the case of multilayer capacitors shown in Figures 21-24 and described later, steps A, B, C, and subsequent repeating step B are repeated any number of times to form layers. In particular, in the case of multilayer capacitors, a protective varnish or other protective device or barrier layer may then be applied in an optional step D. This is preferably made of a temperature-stable, inert, hydrophobic hydrocarbon such as parylene or a fluorine-based hydrocarbon (EFTE, PTFE, or equivalent). This can be applied using a vapor deposition method or a solvent-based coating method, such as spray coating or screen printing. The barrier layer is not applied to the surfaces where the internal electrodes or electrodes of the multilayer component are exposed. In the final step E, side contacts or external electrodes are applied to the surfaces where each (internal) electrode is exposed. These may be made of brass, copper, and tin or aluminum or silver. Other suitable conductive materials, preferably metallic materials, may also be used for this purpose.

[0132] In the case of multilayer capacitors, the electrodes that act as internal electrodes can be structured.

[0133] Alternatively, the dielectric layer can be manufactured by depositing the layer from a solution onto a substrate provided with a suitable release agent, rather than applying it directly to the electrodes. After the crosslinking step, which can be performed as described above, a film can be produced, which can then be further processed into a multilayer capacitor or a wound capacitor.

[0134] Alternative methods for producing the film include calendering or reactive extrusion. In particular, reactive components, namely polymer chains and linker molecules having reactive groups, can be mixed together using a twin-screw extruder, and these can react with each other simultaneously. A film can then be formed from the crosslinked reactive material by calendering. This method is preferred for the manufacture of wound capacitors and "stacked" capacitors manufactured by winding. The film or layer thus produced can then be metallized on both sides to produce the first electrode.

[0135] Capacitors manufactured using the method according to the present invention have an operating temperature exceeding 150°C.

[0136] Figure 15 shows the thermogravimetric analysis of pure poly(glycidyl methacrylate). This exhibits relative and absolute crosslinking degrees exceeding 25%, with each repeating unit having exactly one reactive group. The thermogravimetric analysis was performed in air using a heating rate of 10 Kelvin per minute. As the thermogravimetric analysis shows, there is almost no mass loss below 240°C. Mass loss exceeding 5% can only be observed above 240°C. A sharp decrease in actual mass can also only be observed above 250°C. Therefore, the corresponding material according to the present invention is suitable for use at temperatures above 150°C. The corresponding material according to the present invention is also suitable for use in components connected by soldering. This material can easily withstand the normal conditions of soldering.

[0137] Figure 16 shows the thermogravimetric analysis of copolymers having repeating units of glycidyl methacrylate and butyl methacrylate, where the proportion of glycidyl methacrylate was 20% and the proportion of butyl methacrylate was 80%. The relative degree of crosslinking, i.e., the proportion of crosslinked glycidyl groups, was also 25%. Other conditions were consistent with those of the thermogravimetric analysis in Figure 15.

[0138] The copolymer exhibits slightly lower temperature stability compared to the homopolymer in Figure 15, but this makes it suitable for use at temperatures above 150°C. This slight decrease in temperature stability is due to the lower absolute or mass-related degree of crosslinking compared to the homopolymer in Figure 15, resulting from the proportion of butyl methacrylate repeating units.

[0139] However, this copolymer has the advantage of being more resistant to water due to the reduced glycidyl methacrylate content. The butyl groups in the butyl methacrylate repeating units are hydrophobic and can therefore counteract the water-reactive properties of the remaining glycidyl groups.

[0140] Figure 17 shows two graphs of the temperature behavior of the loss coefficient tanδ.

[0141] In the upper presentation or graph of Figure 17, the frequency-dependent loss coefficient tanδ was measured as a function of frequency at a temperature of 130°C. In the presentation at 130°C, the curve for the uncrosslinked polymer (VG0%) is shown in comparison to the curve for the polymer with a relative degree of crosslinking greater than 70% (VG>70%). The uncrosslinked polymer (VG0%) is consistent with the polymer used in the present invention, except that no crosslinking was performed.

[0142] Thus, the loss coefficient at 130°C for non-crosslinked polymers (VG0%) shows a strong frequency dependence. In contrast, the dissipation rate at 130°C for polymers with a relative crosslinking degree greater than 70% (VG>70%) is 10 3 ~10 6 It remains almost constant at a value of 0.02 across the frequency range of Hz.

[0143] Similar behavior can be observed at 150°C for polymers with a relative crosslinking degree exceeding 70% (VG>70%). At a temperature of 180°C (not shown), a similar, almost constant graph curve is again obtained for polymers with a relative crosslinking degree exceeding 70% (VG>70%), where the loss factor is approximately 0.04 higher.

[0144] Figure 17 shows that the degree of crosslinking can significantly contribute to temperature stability and a reduction in the loss coefficient.

[0145] Figure 18 shows the frequency dependence of the dielectric constant of two dielectric layers at a temperature of 150°C. The upper curve shows the behavior of a polymer (VG > 70%, GA > 70%) with a relative degree of crosslinking exceeding 70% and a glycidyl methacrylate content exceeding 70%. The relative degree of crosslinking of this polymer (VG > 70%, GA > 70%) was 95%. The glycidyl methacrylate content was 100%. The lower curve shows the behavior of a polymer (VG < 70%, GA < 70%) with a relative degree of crosslinking less than 70% and a glycidyl methacrylate content less than 70%. The relative degree of crosslinking of this polymer (VG < 70%, GA < 70%) was 45%. The proportion of glycidyl methacrylate was 五十%. In both cases, these are polymers according to the present invention. Thus, in both cases, the dielectric constant far exceeds 3 and is almost constant over the entire frequency range from 10 3 ~10 6 Hz. However, it can be observed that a higher relative degree of crosslinking and a higher glycidyl methacrylate content result in an increase in the dielectric constant ε r .

[0146] Therefore, it can be shown that by using the polymer according to the present invention, a constant dielectric constant exceeding 3 or even exceeding 4 can be achieved over a wide frequency range.

[0147] This tendency can also be recognized from the examples in Table 1.

[0148] Table 1 shows the values of the loss factor tanδ and the dielectric constant ε r of polymers with different compositions and relative degrees of crosslinking at different frequencies and different temperatures. "rel.Crosslinking" refers to the relative degree of crosslinking. "Glycidyl" refers to the glycidyl methacrylate content. "Non-polar group" refers to the proportion of repeating units containing non-polar groups.

[0149] It should be noted that the "五十%" in the translation of item should be corrected according to the correct content in the original text. Also, some tags like 3 , 6 , etc. are likely specific identifiers in a particular context and may not have a direct semantic translation but are preserved as required.In particular, Table 1 shows three different copolymer compositions containing polyacrylates having glycidyl groups and nonpolar groups in different compositions. Here, it can be seen that all of these molecules exhibit both favorable loss coefficients and favorable dielectric constants over a wide frequency range. However, the dielectric constant is particularly high in highly crosslinked systems, while the loss coefficient or the stability of the loss coefficient can be improved in less crosslinked systems.

[0150] [Table 1]

[0151] Therefore, within the scope of the present invention, materials can be tailor-made according to technically relevant specifications, having a particularly good relative permittivity of approximately 5 or a material that is as constant as possible with respect to the loss coefficient. It should be noted that the corresponding other properties remain sufficient, even in extreme cases.

[0152] Figure 19 shows a statistical evaluation of the breakdown voltage of a system with a glycidyl methacrylate content of 50% and a relative degree of crosslinking of 95%. Other monomers have nonpolar groups. Measurements were performed on a metal foil coated with a dielectric layer approximately 3 μm thick. The metal foil served as the first electrode. The second electrode was fabricated by sputtering. Measurements were performed using a voltage ramp of 20 kV per minute and a maximum current of approximately 10 mA. It was shown that voltage breakdown could only be achieved well above 250 V. Furthermore, a breakdown voltage stability of 500 V could be achieved in the majority of tests.

[0153] Figure 20 shows a schematic cross-section of a first exemplary embodiment of the multilayer capacitor 1. The multilayer capacitor 1 has multiple electrodes 3 stacked alternately with electrode 4. Both electrodes are planar electrodes. The dielectric layer 2 conceptually corresponds to the dielectric layer 2 from the exemplary embodiment of the simple capacitor shown in Figure 1 and is located between the first electrode 3 and the second electrode 4, i.e., between two adjacent electrodes in each case.

[0154] The first electrode 3 and the second electrode 4 have the characteristics of internal electrodes. The first external contact 5 and the second external contact 6 are located on opposite sides of the multilayer capacitor, with the first external contact electrically connecting to the first electrode 3 and the second external contact electrically connecting to the second electrode 4.

[0155] The capacitor formed in this manner can become a surface-mount device (SMD), which is very suitable for soldering due to its temperature-stable dielectric layer 2.

[0156] To allow the multilayer capacitor 1 to be used more advantageously as an SMD component, the external contacts 5 and 6 may have a clamp-type structure (not shown). Thus, the external contacts 5 and 6 may extend to a small extent along the stacking direction of the side surface used as the top or bottom surface of the structure.

[0157] Capacitor 1 may be, for example, cubic and consist of a total of 1000 repeating units. The repeating units of a multilayer capacitor should not be confused with the repeating units of polymer chains. The number of repeating units may be greater. Each repeating unit consists of a first electrode 3, a dielectric layer 2, an optional second electrode 4, and a further dielectric layer 2. Capacitor 1 may have a length of 3-4 mm, a width of 2-3 mm, and a height of 1-2 mm. Individual dielectric layers may have a thickness of 500 nm to 5 μm. A preferred thickness is 500 nm to 2 μm. The internal electrodes may have a thickness of 10-50 nm, preferably 20 nm.

[0158] Figure 21 shows a second exemplary embodiment of a multilayer capacitor. The capacitor in Figure 21 largely corresponds to the capacitor shown in Figure 20 and described above. However, in the example shown in Figure 21, the original substrate used in the method, which is here labeled as substrate 7, is still present in the component. In the example shown in Figure 21, substrate 7 is insulating. It may be, for example, a glass substrate, a semiconductor wafer, or a flexible substrate such as a polyimide film or release tape.

[0159] Figure 22 shows a schematic cross-section of a third exemplary embodiment of the multilayer capacitor 1. The exemplary embodiment shown in Figure 22 is very similar to the example shown in Figure 21. However, here the substrate 7 is a metallic conductive substrate, made of, for example, aluminum, copper, or a similar material. The substrate 7 exists here, for example, as foil. Due to its conductive properties, it is not necessary to apply a conductive layer to the substrate as the first electrode 3. The substrate itself can function as a substitute for one of the first electrodes 3. The dielectric layer can be applied directly to the substrate, or to the substrate as a substitute electrode. The above method can be adapted depending on the situation. Here, it should be noted that care must be taken to ensure that the second external contact 5 does not electrically contact the substrate 7, since it is preferable that the substrate extends across the entire width and length of the capacitor.

[0160] Figure 23 shows a fifth example of the multilayer capacitor 1. This corresponds to the example shown in Figure 20, but each of the external contacts 5 and 6 also has wirings 8 and 9 that allow for through-hole mounting on a circuit board or in the application. The capacitor shown in Figure 23 is therefore a through-hole capacitor. Wirings 8 and 9 create electrical contact, and preferably mechanical contact, with the coupling point in the application. Wirings 8 and 9 can be coupled to the capacitor 1 or the external contacts 5 and 6 by any method, such as bonding.

[0161] Figure 24 shows a schematic cross-section of an example of a wound capacitor 1. In its basic structure, the wound capacitor is similar to the first example shown in Figure 1. The dielectric layer 2 is sandwiched between the first electrode 3 and the second electrode 4. Correspondingly, a relatively thin, planar sandwich-like structure is wound to form the wound capacitor. The preferred layer thickness of the wound capacitor having a dielectric layer according to the present invention is in the range of 1 μm to 10 μm. A preferred layer thickness is 2 μm to 5 μm.

[0162] [Explanation of symbols] 1 Capacitor 2 Dielectric layers 3. First electrode 4. Second electrode 5. First external contact 6. Second external contact 7 circuit boards 8. First wiring 9. Second wiring

Claims

1. A method for manufacturing a capacitor (1), comprising the steps of manufacturing a dielectric layer (2) on a first electrode (3) and attaching a second electrode (4) on the dielectric layer (2), wherein the step of manufacturing the dielectric layer (2) is as follows: The polymer chains are branched from each other and have reactive groups suitable for forming covalent bonds with linker molecules. Adding linker molecules to a polymer chain, wherein each linker molecule has at least two chemical linkage points, and each chemical linkage point is capable of forming a covalent bond with a reactive group; The polymer chain is crosslinked by covalent bonding between at least two reactive groups and a linker molecule, wherein the proportion of reactive groups covalently bonded to the linker molecule is 70% to 99%. Methods that include...

2. The method according to claim 1, wherein the proportion of repeating units having a reactive group relative to all repeating units is 20% to 100%.

3. The method according to claim 1, wherein at least a portion of the repeating units having a reactive group is an acrylate repeating unit, and in the acrylate repeating unit, the reactive group is bonded in the form of an ester bond via the carboxylate group of the acrylate repeating unit.

4. The method according to claim 1, wherein the reactive group comprises an epoxide, and the linker molecule comprises a functional group selected from carboxylic acids, amines, alcohols, and anhydrides.

5. S Ｎ 1 or S Ｎ The method according to claim 1, wherein a reaction or addition / desorption mechanism is involved in crosslinking.

6. The method according to claim 1, wherein Markovnikov addition or inverse Markovnikov addition is involved in the bridging.

7. The method according to claim 1, comprising the step of depositing or reaction extrusion from a solution.

8. The method according to claim 1, wherein the polymer chain is a copolymer comprising acrylate repeating units and repeating units having nonpolar groups, the nonpolar groups are selected from unsaturated or aromatic groups, and the proportion of acrylate repeating units is 20 to 80%.

9. The method according to claim 1, wherein the crosslinking is carried out by annealing at a temperature suitable for causing a crosslinking reaction to more than 99% of a component selected from reactive groups and linker molecules present in small proportions of the reaction equivalent.

10. The method according to claim 1, wherein the proportion of repeating units having a reactive group relative to all repeating units is 40% to 70%.

11. The method according to claim 1, wherein the proportion of reactive groups covalently bonded to the linker molecule is 95% to 99%.

12. A capacitor (1) having two electrodes (3, 4) in contact with one surface and the other surface of a dielectric layer (2), The dielectric layer (2) has a polymer material in which the polymer main chain or different parts of the polymer main chain are covalently linked to each other via crosslinking linker molecules. Capacitor (1), wherein the proportion of repeating units covalently linked to the linker molecule via functional groups is 70% to 99% of the total of these repeating units and repeating units having functional groups suitable for covalent linkage to the linker molecule.

13. The capacitor (1) according to claim 12, wherein the proportion of repeating units in which linker molecules are covalently bonded is 5% to 99%.

14. The capacitor (1) according to claim 12, wherein the polymer main chain comprises acrylate repeating units covalently bonded to a linker molecule, or functional groups suitable for such bonding are bonded in the form of ester bonds via the carboxylate groups of each acrylate repeating unit.

15. The capacitor (1) according to claim 12, wherein the covalent compound is selected from ether crosslinking, ester crosslinking, amine crosslinking, amide crosslinking, and thioether crosslinking.

16. The capacitor (1) according to claim 12, wherein electrodes (3, 4) are stacked alternately with a dielectric layer (2), and the electrodes (3, 4) are in contact via external contacts (5, 6).

17. The capacitor (1) according to claim 12, wherein the proportion of repeating units in which linker molecules are covalently bonded is 40% to 70%.

18. The capacitor (1) according to claim 12, wherein the proportion of repeating units covalently linked to the linker molecule via functional groups is 95% to 99% of the total of these repeating units and repeating units having functional groups suitable for covalent linkage to the linker molecule.

19. A wound-type capacitor having a first electrode (3) and a dielectric layer (2), The dielectric layer (2) has a polymer material in which the polymer main chain or different parts of the polymer main chain are covalently linked to each other via crosslinking linker molecules. The proportion of repeating units covalently linked to the linker molecule via functional groups is 70% to 99% of the total of these repeating units and repeating units having functional groups suitable for covalent linkage to the linker molecule. A wound capacitor in which the dielectric layer (2) and the first electrode (3) are wound together to form a capacitor roll.

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