Conductive textile yarn, thread or strand

Abstract

The invention relates to conductive textile yarns, threads, or strands for textile-technological structure production, in particular for electronic textiles with active and / or passive electronic components, wherein the yarn, thread, or strand has an electrically insulating sheath or coating around its core. According to the invention, the sheath or coating has thermally meltable properties and, while maintaining its high resistance, is provided with a homogeneous doping of conductive microparticles, wherein a local, time-controlled application of temperature and pressure to the sheath or coating allows for the creation of a localized, electrically conductive access point to the core.

Description

[0001] The invention relates to a conductive textile yarn, thread or strand for textile-technological structure production, in particular for electronic textiles or textiles provided with electronic components with active and / or passive electronic components, wherein the yarn, thread or strand has an electrically insulating sheath or coating around its core, according to the preamble of claim 1.

[0002] The invention further relates to a circuit carrier with a plurality of conductive textile yarns, threads or strands for forming a complex textile structure and to a method for producing conductive textile yarns, threads or strands for further processing into textile structures.

[0003] From WO 18176121 A1, a contact sensor element is already known which contains a low-density material based on conductive microparticles.

[0004] These conductive microparticles have an initial conductivity when no compression process takes place.

[0005] The conductivity changes when compression is applied.

[0006] According to the patent family WO 22044913 A1, coated particles are part of the state of the art, wherein the conductive particles are coated with an insulating layer.

[0007] This insulating layer can be melted through thermocompression bonding. This exposes a metallic surface of the corresponding conductive particle, thus achieving electrical conductivity throughout the entire structure or layer.

[0008] US Patent No. 8,679,621 B discloses an electrical conductor that can be repaired in the event of damage. A conductive liquid is embedded in the conductor. If a crack or other mechanical damage releases the conductive particles, they can largely restore the overall conductivity.

[0009] US Pat. No. 4,624,798 A discloses a conductive microparticle mass embedded in a matrix of electrically non-conductive materials. When such a rubber-like material is compressed, the conductive particles touch each other, and the composite material becomes an electrical conductor.

[0010] Textile electronic circuits based on conductive fibers are already known. Circuits based on flexible, foil-based circuit carriers are coated with insulating varnishes to protect them against environmental influences, especially against moisture penetration.

[0011] Such coatings can, in principle, also be applied to flat textile circuit boards. However, the breathability and flexibility of the actual circuit board, and thus the advantage over traditional flexible substrates, are lost. According to the current state of the art, contacting passive or active electronic components requires removing the insulation from the conductor tracks integrated into the textile. In addition, contacting agents such as solder pastes or conductive adhesives must be applied, which increases the overall labor and thus the costs of manufacturing such circuit boards and their applications.

[0012] In addition, corrosion occurs at the stripped areas, which, over the long term, impairs or calls into question the desired electrical properties.

[0013] From the above, it is therefore an object of the invention to provide further developed textile yarns, threads or strands for textile-technological structure production, with the aid of which even complex circuit carriers can be realized in a cost-reducing and simple manner and wherein the circuit-technically necessary connection of individual conductor tracks within the structure or the contacting to assembly components can be carried out without stripping measures, wherein the created electrical contacts or connections remain stable over the long term.

[0014] The object of the invention is achieved by a conductive textile yarn, thread or strand according to the combination of features according to claim 1, by a circuit carrier with a plurality of conductive textile yarns, threads or strands according to the present invention and by a method for producing conductive textile yarns, threads or strands for further processing into textile structures.

[0015] It is therefore assumed that a conductive textile yarn, thread or strand is used to create a textile-technological structure.

[0016] These textile yarns, threads, or strands are intended to be used in particular for electronic textiles with active and / or passive electronic components, i.e., they are or can be used in so-called smart textiles. Conductive threads are already known, for example, under the applicant's brand name Elitex.

[0017] Active components include, for example, circuits, light-emitting diodes, transistors or other optoelectronic components.

[0018] Passive components include resistors, capacitors, inductors, but also connectors, switches, buttons or similar devices.

[0019] The conductive textile yarn, thread or strand according to the invention has an electrically insulating sheath or coating formed around the core.

[0020] According to the invention, the sheath or coating can now be thermally melted and provided with a homogeneous doping of conductive microparticles while maintaining its high resistance.

[0021] By applying local, time-controlled temperature and pressure to the casing or coating, a point-like, electrically conductive access to the core can now be created.

[0022] For example, such a measure can achieve a permanent electrical and mechanical connection at the intersection of two threads without the need to remove the insulation sheath at the node or connection point mechanically or by other suitable methods.

[0023] A coating doped with conductive microparticles is used for the conductive thread materials, whereby the coating melts after thermal pressure loading and thus creates contact between conductive threads or yarns or strands with each other or with the aforementioned components.

[0024] For electrical contacting, a low concentration of conductive microparticles of only about 60 particles / mm 2 is sufficient, which corresponds to a particle concentration of 1-5 mass% depending on the selected metallic microparticles.

[0025] With advantageously low particle concentrations and the use of particles that are as round as possible, these lie in the coating without touching each other.

[0026] Electrical surface resistances of conductive particles in the coating present in the aforementioned concentration range are therefore in the gigaohm range.

[0027] The coating layer thickness is preferably in the range of 100 to 300 µm. In addition to the protective effect of the coating due to the base materials, particularly polymer-based ones, corrosion inhibitors may also be present or embedded in the coating material.

[0028] Generally, base polymers such as thermoplastic, thermally processable, or thermally vulnerable polyurethane or copolyester are used for the coating. These base polymers are mixed with conductive microparticles, such as round, silver-coated aluminum particles.

[0029] According to the invention, there is further provided a circuit carrier with a plurality of conductive textile yarns, threads or strands which have been further developed in the manner described above, wherein these are incorporated into a complex textile structure, in particular into so-called smart textiles.

[0030] At intersections of conductor tracks or at contact points to electronic components, contact points are then formed in the circuit carrier by means of a time-controlled pressure / temperature process.

[0031] The process according to the invention for producing conductive textile yarns, threads or strands for further processing into textile structures is based on the following steps.

[0032] First, conductive textile threads, yarns or strands are provided in a known manner.

[0033] This is followed by the production of a thread coating compound with a base polymer loaded with conductive microparticles.

[0034] The loading ranges from 1 to 5 mass%. The microparticle load is homogenized for even distribution in the base polymer.

[0035] The thread coating compound is then used to coat or enclose the respective conductive textile threads, yarns or strands in such a way that the insulating effect of the coating is maintained.

[0036] For quality assurance purposes, the appropriately treated thread is tested for defects in the core or sheath, with subsequent release of the resulting precursor product for the construction of textile circuit or wiring carriers.

[0037] The invention will be explained in more detail using an embodiment and a figure.

[0038] Here, Fig. 1a a principle cross-sectional view through a textile-processable electrical conductor with a covering which has conductive particles and which has an insulating effect, and Fig. 1b a view similar to that according to Fig. 1a , however, an electrical contact has been established with the conductive core, the contact being achieved by a pressure-temperature treatment process as a result of which the conductive microparticles touch each other and establish the conductive connection, but without there being or having to be direct contact between the conductor core and the external contact.

[0039] According to the exemplary embodiment, a conductive textile yarn, thread or strand 1 is assumed, which represents the core of the yarn or thread 1 provided with an insulating sheath 2.

[0040] The insulation coating 2 consists of a base polymer and has a homogeneous doping of conductive microparticles 3.

[0041] The doping of the coating mass with conductive microparticles 3 is carried out homogeneously with a possible uniform distribution of the microparticles 3, so that the high resistance and insulating effect of the coating is fundamentally maintained.

[0042] The surface resistance of the sheath in the state according to Figur 1a is in the range ≥ 1 megaohm.

[0043] The dimensions of the microparticles 3 are in the range of 5-60 µm, with a surface area of ​​10-20 particles per 0.25 mm 2< being envisaged.

[0044] This means that approximately 1-5 mass% of conductive particles are present in the coating.

[0045] If the formation of an electrical connection between the yarn 1 or the conductive core to an external contact 4 is required, a locally limited pressure-temperature-time treatment process takes place, symbolized by the arrow and the abbreviations p and T.

[0046] Upon completion of this pressure-temperature treatment, the number of microparticles 3 in the contacting or connecting area increases, with the result that the conductive microparticles 3 create current paths and thus a connection between the external contact 4 and the yarn 1.

[0047] The remaining insulation sheath 2 outside the contact area retains its high resistance and thus its insulating effect.

[0048] If the conductive textile yarn or thread according to the invention is processed using textile technology and a coating with conductive microparticles is used in such a way that the coating has anisotropic conductive properties, a textile structure can be produced without any short circuits.

[0049] Only by the action of a pressure in the range of e.g. 1-2 bar with simultaneous temperature influence in the range of e.g. 110-170° on the sheath, the electrical contacts between the external contact 4 and the conductive core of the yarn 1 or between two threads at a thread crossing are formed.

[0050] The external contact 4 also represents, for example, a connection leg or a connection surface of an electronic component.

Claims

1. Conductive textile yarn, thread or strand for textile-technological structure production, in particular for electronic textiles with active and / or passive electronic components, wherein the yarn, thread or strand has an electrically insulating sheath (2) or coating around its core (1), characterized in that the sheath or coating (2) is thermally meltable and, while maintaining its high resistance, has a homogeneous doping of conductive microparticles (3), wherein a point-like, electrically conductive access to the core (1) can be formed by local, time-controlled temperature and pressure action on the sheath or coating (2).

2. Conductive textile yarn, thread or strand according to claim 1, characterized in that the surface resistance of the sheath or coating (2) is in the range of ≥ 1 megaohm.

3. Conductive textile yarn, thread or strand according to claim 1 or 2, characterized in thatthe microparticles (3) have dimensions in the range of 5-60 µm, with a number of 10-20 particles per 0.25 mm 2 is intended.

4. Conductive textile yarn, thread or strand according to one of the preceding claims, characterized in that the thickness of the coating or cladding is in the range of 100-300 µm.

5. Conductive textile yarn, thread or strand according to one of the preceding claims, characterized in that the coating or casing (2) contains 1-5 mass% of conductive microparticles (3).

6. Conductive textile yarn, thread or strand according to one of the preceding claims, characterized in that the sheath or coating (2) of the core (1) contains corrosion inhibitors.

7. Conductive textile yarn, thread or strand according to one of the preceding claims, characterized in that the coating or casing (2) is polymer-based.

8. Circuit carrier with a plurality of conductive textile yarns, threads or strands according to at least one of the preceding claims, characterized in that which is incorporated into complex textile structures.

9. Circuit carrier according to claim 8, characterized in that At intersections of conductor tracks, contact points to the respective thread core are formed by means of a time-controlled pressure-temperature treatment process.

10. A process for producing conductive textile yarns, threads or strands for further processing into textile structures, comprising the following steps: - Providing the conductive textile starting thread, yarn or strand; - Producing a thread coating compound with a base polymer which is mixed or loaded with conductive microparticles in the range of 1-5 mass% and homogenizing the microparticle distribution in the base polymer; - Coating or encasing the conductive textile thread, yarn or strand with the thread coating compound in such a way that the insulating effect of the sheath or coating is retained; - Testing the thread, yarn or strand for defects in the core or the sheath or coating; and - Releasing the resulting intermediate product for the construction of textile circuit or wiring carriers.

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