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 technology structure production, in particular for electronic textiles or textiles equipped with electronic components with active and / or passive electronic components, wherein the yarn, thread or strand has an electrically insulating covering 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 known which contains a low density material based on conductive microparticles.

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

[0005] The conductivity changes when compression is performed.

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

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

[0008] US Patent 8679621 B discloses an electrical conductor that can be repaired if damaged. A conductive fluid is embedded within the conductor. If a crack or other mechanical damage releases the conductive particles, they can largely restore the overall conductivity.

[0009] US patent 4624798 A describes a conductive microparticle mass embedded in a matrix of electrically non-conductive materials. When such a rubber-like material is compressed, the conductive particles come into contact and the composite material becomes an electrical conductor.

[0010] EP 3 251 473 B1 describes the application of pressure and heat to enable a mechanical connection between a textile fabric, electrically conductive threads and electrical contacts.

[0011] Textile electronic circuits based on conductive fibers are already known. Circuits based on flexible, film-based circuit carriers are coated with insulating varnishes to protect them against environmental influences, especially against the ingress of moisture.

[0012] In principle, such coatings can also be applied to flat textile circuit carriers. However, the breathability and flexibility of the actual circuit carrier, and thus the advantage over conventional flexible substrates, are lost. According to the current state of the art, contacting passive or active electronic components requires removing the insulation from the conductive traces integrated into the textile. Furthermore, auxiliary materials such as solder paste or conductive adhesive must be applied for contacting, which increases the overall labor and therefore the costs of manufacturing such circuit carriers and their applications.

[0013] Furthermore, corrosion occurs at the exposed areas, which, in the long term, deteriorates or calls into question the desired electrical properties.

[0014] Based on the above, the object of the invention is therefore to provide further developed textile yarns, threads or strands for textile-technological structure production, with the help of which 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, whereby the created electrical contacts or connections remain stable over a long period of time.

[0015] The problem of the invention is solved 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.

[0016] It is therefore assumed that a conductive textile yarn, thread or strand is used for textile-technological structure generation.

[0017] These textile yarns, threads, or strands are intended for use in particular in electronic textiles with active and / or passive electronic components, i.e., they are to be used or can be used in so-called smart textiles. Conductive threads, for example, are already known to the applicant under the brand name Elitex.

[0018] Active components include, for example, circuits, light-emitting diodes, transistors, or other optoelectronic components.

[0019] Passive components include resistors, capacitors, inductors, but also connectors, switches, pushbuttons or similar devices.

[0020] The conductive textile yarn, thread or strand according to the invention has an electrically insulating covering or coating formed around the core.

[0021] According to the invention, the coating or covering is thermally meltable and, while maintaining its high resistance, is provided with a homogeneous doping of conductive microparticles.

[0022] 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.

[0023] For example, such a measure can create a permanent electrical and mechanical connection at the intersection of two threads without the need to remove the insulation covering mechanically or by other suitable methods at the node or connection point beforehand.

[0024] A coating doped with conductive microparticles is used for the conductive thread materials, whereby the coating melts after thermal pressure stress and thus establishes contact between conductive threads or yarns or strands among themselves or with the aforementioned components.

[0025] For electrical contacting, a low concentration of conductive microparticles of only about 60 particles / mm² is sufficient, which corresponds to a particle concentration of 1-5 mass-% depending on the selected metallic microparticles.

[0026] 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.

[0027] The electrical surface resistances of conductive particles present in the coating within the aforementioned concentration range are therefore in the gigaohm range.

[0028] The coating 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, which are particularly polymer-based, corrosion inhibitors may also be present or embedded in the coating material.

[0029] In principle, base polymers such as thermoplastic, thermally processable, or thermally fragile polyurethane or copolyester are used for the coating. These base polymers are mixed with conductive microparticles, for example, round, silver-coated aluminum particles.

[0030] According to the invention, a circuit carrier is further comprised of 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.

[0031] At intersections of conductor tracks or at contact points with electronic components, contact points are then formed in the circuit carrier by means of a time-controlled pressure / temperature process.

[0032] The inventive method for producing conductive textile yarns, threads or strands for further processing into textile structures starts with the following steps.

[0033] First, conductive textile threads, yarns or strands are provided, as is known in the first place.

[0034] This is followed by the production of a thread coating compound with a base polymer loaded with conductive microparticles.

[0035] The loading is in the range of 1 to 5% by mass. The microparticle loading is homogenized to ensure uniform distribution within the base polymer.

[0036] The thread coating compound is then used to coat or wrap the conductive textile threads, yarns or strands in question, in such a way that the insulating effect of the wrapping is maintained.

[0037] For quality assurance, the appropriately equipped thread is tested for defects in the core or sheath, followed by the release of the resulting pre-product for the construction of textile circuit or wiring carriers.

[0038] The invention will be explained in more detail with reference to an exemplary embodiment and a figure. Here they show

[0039] Fig. 1a shows a principle cross-sectional view through a textile-processable electrical conductor with a coating which has conductive particles and which has an insulating effect, and Fig. 1a shows a representation similar to that according to Fig. 1a , however, an electrical contact with the conductive core was established, the contact being achieved by a pressure-temperature treatment process in which the conductive microparticles touch each other and establish the conductive connection, without, however, there being or needing to be direct contact between the conductor core and the external contact.

[0040] According to the exemplary embodiment, a conductive textile yarn, thread or strand 1 is assumed, which forms the core of the yarn or thread 1 provided with an insulating covering 2.

[0041] The insulation coating 2 consists of a base polymer and has a homogeneous doping of conductive microparticles 3.

[0042] 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.

[0043] The surface resistance of the enclosing in the state according to Figur 1a is in the range ≥ 1 megaohm.

[0044] The dimensions of the microparticles 3 are in the range of 5-60 µm, with an area of ​​10-20 particles per 0.25 mm²< provided.

[0045] This means that approximately 1-5% by mass of conductive particles are present in the coating.

[0046] 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 representation and the abbreviations p and T.

[0047] The execution of this pressure-temperature treatment leads to an increase in the number of microparticles 3 in the contacting or connection area, with the result that the conductive microparticles 3 create current paths and thus a connection between the external contact 4 and the yarn 1.

[0048] The remaining insulation covering 2 outside the contact area retains its high resistance and thus its insulating effect.

[0049] If the conductive textile yarn or thread according to the invention is processed using textile technology and a covering with conductive microparticles is used in such a way that the covering has anisotropic conductive properties, a textile structure can be created without any short circuits.

[0050] Only when a pressure in the range of, for example, 1-2 bar is applied to the covering, combined with a temperature in the range of, for example, 110-170°, do the electrical contacts form between the outer contact 4 and the conductive core of the yarn 1, or between two threads at a thread intersection.

[0051] The external contact 4, for example, also represents a connecting leg or a connecting surface of an electronic component.

Claims

1. Conductive textile yarn, thread, or strand for textile-technology structure formation, 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 (1), characterized in that the sheath or coating (2) is thermally fusible and, while retaining its high resistance, has a homogeneous loading of conductive microparticles (3), whereby a point-specific electrically conductive access to the core (1) can be formed by local, time-controlled application of temperature and pressure to 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 that the microparticles (3) have dimensions in the range of 5-60 µm, a number of 10-20 particles per 0.25 mm2 being provided.

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

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

6. Conductive textile yarn, thread, or strand according to any 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 any one of the preceding claims, characterized in that the sheath or coating (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 it is incorporated into complex textile structures.

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

10. Method 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 composition with a base polymer loaded with conductive microparticles in an amount of 1-5 wt.% and homogenizing the distribution of the microparticles in the base polymer; • coating or sheathing the conductive textile thread, yarn, or strand with the thread coating composition such that the insulating effect of the sheath or coating is retained; • inspecting the thread, yarn, or strand for defects in the core or the sheath or coating; and • releasing the obtained intermediate product for constructing textile circuit or wiring carriers.

Images