WO2022101000A1

WO2022101000A1 - Functional textile, method for forming a functional textile, and use of a functional textile

Info

Publication number: WO2022101000A1
Application number: PCT/EP2021/079637
Authority: WO
Inventors: Stefan Müller; Joachim Weis
Original assignee: Müller Textil GmbH
Priority date: 2020-11-11
Filing date: 2021-10-26
Publication date: 2022-05-19
Also published as: DE102020129775B3; KR20230113323A; CN116457516A; JP2023548222A

Abstract

The invention relates to a functional textile having: a base textile; a plurality of metal functional conductors (6) provided with insulation (5a); and at least one first metal connecting conductor (7) provided with insulation (5b), wherein the functional conductors (6) are connected to the first connecting conductor (7) at contact points (9) which are mutually spaced along the first connecting conductor (7). According to the invention, the insulation (5a) of the functional conductors (6) and the insulation (5b) of the first connecting conductor (7) are at least partially displaced and/or removed at the contact points (9), and the functional conductors (6) and the first connecting conductor (7) are connected via an integral metal-to-metal bond at the contact points (9). The invention also relates to a method for forming the functional textile and to a use of the functional textile.

Description

Functional textile, method for forming a functional textile and use of a functional textile

Description:

The invention relates to a functional textile with a base textile, with a plurality of metallic functional conductors provided with insulation and with at least one metallic first connecting conductor provided with insulation, the functional conductors being connected to the connecting conductor at contact points spaced apart from one another along the first connecting conductor.

The present invention relates to a functional textile with conductive properties, it being possible for such a functional textile to be used advantageously for heating purposes. It is known, for example, to use functional textiles to heat seat surfaces, backrests or interior trim parts in motor vehicles.

Within the scope of the invention, the functional textile comprises a base textile, which is usually formed from threads, in particular from plastic threads, with the metallic functional conductors provided with insulation also being held by the base textile.

Within the scope of the invention, fundamentally different textiles with a uniform structure can be considered. Corresponding textiles with a regular or essentially regular structure can be produced, for example, by warp-knitting, knitting or weaving. In principle, however, the base textile can also be formed from a fleece (nonwoven), in which case individual threads or fibers are then randomly arranged, laid down and aligned to a certain extent. Within the scope of the invention, the base textile can in particular also be a spacer textile. According to their general structure, spacer textiles comprise a first flat textile layer, a second flat textile layer spaced apart therefrom and usually arranged parallel, and spacer threads connecting the textile layers to one another.

Spacer fabrics can be used to form heating textiles. Spacer fabrics are characterized by a low basis weight, a comparatively open and air-permeable structure and elastic properties in the thickness direction. In the case of spacer fabrics with a first planar knitted layer, a second planar knitted layer and spacer threads connecting the knitted layers, the heating conductors are then incorporated into the structure of the corresponding knitted layer, which is usually formed from plastic threads.

A functional textile in the form of a knitted spacer section is known from DE 10 2006 038 612 A1, with non-insulated heating conductors being incorporated into a flat knitted layer and touching one another. Such a configuration forms a flat, conductive structure that can be contacted by two lateral, knitted-in connection conductors. Since all conductor threads form a common electrically conductive structure with a large number of contact points, point-to-point contact is generally sufficient. However, under certain circumstances, locally uneven or insufficient heating can also occur in practice.

DE 10 2018 111 893 A1 describes a heating textile for the transfer of heat, wherein electrically conductive fiber strands are present and wherein the contacting of the fiber strands is also provided by touching contact by means of mesh-like connections. With regard to a long-term function, however, many known heating textiles with non-insulated heating conductors are in need of improvement. In this context, it is also common for functional textiles and in particular heating textiles for use in motor vehicles to be subjected to extremely demanding tests in advance, with mechanical loads being applied, among other things, and the functional textiles also being brought into contact with foreign substances such as conductive and/or oxidizing liquids . In the case of non-insulated heating conductors, failure can result, for example, from corrosion and oxidation.

In order to avoid the disadvantages described with easy-to-contact, non-insulated systems, different approaches have been pursued. Even if corrosion-resistant nickel-copper alloys are used for the heating conductors, the stability is still limited.

According to DE 10 2015 114 778 A1, it is proposed in this connection to provide filaments with a conductive coating, in particular made of silver, as a result of which the tendency to corrosion is at least reduced. However, the costs associated with the production of such a spacer fabric are comparatively high. This applies in particular if the available conductive cross section of the comparatively thin coating is taken as a basis. Durability also needs improvement. It should be noted that a thin coating of metal and especially silver is not very stretchable compared to a filament made of plastic as the core, so that if the entire thread is stretched during production or use, cracks or microcracks can occur in the metallic coating . In the case of a polyamide that is preferred in combination with silver as the material for the filaments, there is then also the problem of swelling when exposed to moisture, which results in more extensive damage.

A generic functional textile in the form of a knitted spacer section is known from DE 10 2009 013 250 B3, with generic insulated systems and alternatively non-insulated systems being described with regard to the heating conductors as functional conductors and connection conductors. In the case of bare functional conductors and a bare connection conductor, reliable contact can be achieved using an electrically conductive adhesive. Furthermore, welding can also take place in that a correspondingly high current flow and the resistance at the contact points result in melting, so that an integral metal-to-metal connection can be formed.

DE 102018 111 893 A1 discloses a textile carrier material for forming a heating element, the contacting also taking place by means of an adhesive, namely a hot-melt adhesive. Mesh threads are also provided for fixing heating conductors to stranded contact conductors.

If, on the other hand, according to the generic configuration, the functional conductors and the at least first connecting conductor are provided with insulation, the insulation can be melted to such an extent that the functional conductors and the first connecting conductor are electrically conductively connected in touching contact. However, with regard to long-term loads or the material tests mentioned above, such designs of the functional textile are also in need of improvement.

Generic functional textiles in the form of spacer fabrics are also known from DE 10 2019 103 934 B3 and DE 10 2019 103 935 A1. In the case of the heating inserts described in the form of a knitted spacer section, a plurality of heating conductors running essentially in a first direction are arranged approximately parallel to one another, with a contact can take place. The specific type of contacting is not specified.

A fabric with conductive functional conductors is known from EP 1 137 322 B1. The conductors, which are preferably formed from carbon fibers, are provided with an insulating coating layer. The functional conductors made of carbon fiber can be brought into touching contact by melting the cladding layer.

In order to avoid the problem of complex contacting, according to DE 10 2009 010 415 A1 a single electrically conductive resistance wire is laid in a meandering pattern in a base textile in the form of a knitted spacer fabric. The production is extremely complex. The arrangement between the knitted layers results in a certain insulation in both directions.

On the other hand, when the functional threads are integrated into one of the knitted layers, it is particularly advantageous that the heating takes place mainly on the corresponding knitted layer, while on the opposite side a certain thermal insulation is already achieved through the spacing by means of the spacer threads and the air layer thus provided between the knitted layers. When heating interiors, for example in motor vehicles, the knitted layer provided with the functional conductors is then expediently aligned in the direction of the interior, so that the opposite heat losses in the direction of the body or the outer skin of such a motor vehicle are minimized.

DE 4 239 068 C2 discloses a spacer fabric with a plurality of heating conductors and two connecting conductors spaced apart from one another. The heating conductors and the connecting conductors can have insulation that is interrupted at the mutual connection points. The exact type of connection is not described.

The present invention is based on the object of specifying a generic functional textile, in particular for heating purposes, which has good functional properties and is particularly robust and resistant. Furthermore, a method for forming the functional textile and a preferred use of the functional textile are also to be specified.

The subject of the invention and the solution to the problem are a functional textile according to patent claim 1, a method for forming a functional textile according to patent claim 13 and the use of a functional textile according to patent claim 19.

Based on a functional textile of the generic type, the invention first provides that the insulation of the functional conductors and the insulation of the first connecting conductor are at least partially displaced and/or removed at the contact points and that the functional conductors and the first connecting conductor at the contact points are replaced by a materially bonded metal-metal connection are connected.

With the cohesive metal-to-metal connection, the metal structure of the respective functional lead merges into the metal structure of the first connection lead at each contact point, in contrast to a merely adjacent contact. The corresponding functional conductors and the first connection conductor are therefore connected directly to one another, at least partially, by soldering or welding, so that the materially bonded metal-to-metal connection alone has a certain strength.

The metal-to-metal connection ensures a low electrical resistance of the contact points. At least up to a certain load limit, the cohesive metal-to-metal connection remains mechanical influences unchanged and can also absorb tensile forces to a certain extent. Relative movements that can lead to contact resistance, electrically induced corrosion or other impairments are thus reliably avoided. The integral metal-to-metal connection is also largely protected against external influences.

In order to produce the material-locking metal-to-metal connection described, in particular using pressure and temperature, the insulation of the functional conductors and the insulation of the first connection conductor are at least partially displaced and/or removed at the contact points. A preferred method, with which such a functional textile can be formed in an advantageous manner, is described below.

According to a preferred development of the invention, it is provided that an insulating material is applied separately to the contact points. This separately applied insulation material can compensate for the fact that the insulation of the functional conductors and the insulation of the first connection conductor at the contact points are at least partially displaced and/or removed. The separately applied insulation material also ensures electrical insulation at the contact points, so that a completely insulated system can be provided overall. Electrochemical corrosion or other impairments are thus largely ruled out, even under the influence of foreign substances. This also results in the advantage that an effective protective layer is provided by the insulation of the functional conductors and the first connection conductor on the one hand and the separately applied insulation material on the other hand.

In addition, the insulation material applied separately to the contact points also provides mechanical reinforcement with certain mechanically balancing properties. In the contact points, the combination nation of the cohesive metal-metal connection on the one hand and the separately applied insulation material on the other hand achieves a particularly high strength and resistance in total, which significantly exceeds the strength alone of the metal-metal connection or alone the strength of a separately applied insulation material.

As also explained below, the insulation of the functional conductors, the insulation of the first connection conductor and the separately applied insulation material are usually formed from a plastic, with different types of plastic being considered. The insulation material that is applied separately usually differs in terms of material from the insulation of the functional conductors and the insulation of the first connection conductor. Accordingly, the different materials on the functional textile itself can be easily analyzed and, if necessary, differentiated.

The functional conductors are intended in particular for heating purposes, although the present invention is not restricted to this. In addition or as an alternative, functional leaders can also be provided, for example, in connection with sensors, occupancy detection or the like.

In the various applications, it is usually provided that the functional conductors have a significantly smaller line cross section and correspondingly a significantly greater resistance in comparison to the first connection conductor. Correspondingly, the functional conductors can preferably each be formed by a comparatively thin wire, in which case the insulation can then be provided, for example, in the form of a lacquer layer. Corresponding enameled wires are available with different metallic materials, in different thicknesses and with different coatings. As will also be described in more detail below, the insulation based on polymers and in particular in the form of an insulating varnish also results in advantages in the production of the functional textile if the functional conductors are incorporated into the base textile. If the functional conductors are processed in a weaving, knitting or knitting process on appropriate textile machines, for example, the plastic-based insulating varnish results in less friction and less wear compared to a bare, uninsulated metal wire.

The insulating varnish can be formed, for example, on the basis of polyurethane, with corresponding varnishes often curing duroplastically.

As already described above, the first connection conductor expediently has a larger line cross section. In this context, according to a preferred embodiment of the invention, it is provided that the first connection conductor is formed by metal strands, in particular copper strands. The stranded copper wire is essentially formed from copper or a copper alloy. The first connection conductor can have a coating of thermoplastic material as insulation, which is extruded onto the metal wire, particularly in the case of an embodiment made of metal wire. When thermoplastic material is extruded on, there is the advantage that the metal strand is sheathed. However, the gaps between the individual wires of the stranded wire are not or only partially filled. In principle, however, the insulation of the first connection conductor can also be formed by a different type of coating, for example by immersion in liquid thermoplastic material or a hardening duroplastic material.

With regard to the processing and handling of the first connection conductor as well as the resilience, as a thermoplastic material as an insulating tion of the first connection conductor preferably a thermoplastic elastomer (TPE) is provided. In principle, all types of thermoplastic elastomers can be used, preference being given to thermoplastic elastomers based on polyester or copolyester (TPE-E).

As also described below in connection with the method for forming the functional textile, the insulating material is usually applied in liquid form to the contact points. In addition to a molten application of thermoplastic material, the separate insulation material can also be applied at room temperature and then harden, depending on the composition. The curing or setting is then expediently effected by activation, in particular by UV light. In this context, it is also possible to set an insulation material that is initially applied in liquid form within a few seconds, for example in about four seconds, by irradiating it with UV light. The functional textile can then be removed quickly and further processed or stored in a particularly advantageous manner. This also results in the advantage that a high level of strength is already provided at the contact points due to the cohesive metal-to-metal connection on the one hand and the insulating material applied on the other.

If, according to the preferred variant described above, the liquid applied insulation material sets by activation, two chemical components can also be brought together (2-component insulation materials and adhesives), with a correspondingly accelerated setting also being achieved by initial contact with air and/or humidity can be achieved.

According to a preferred embodiment of the invention, the functional conductors can be connected in parallel to the first connecting conductor will. Furthermore, for example, two functional conductors assigned to one another can be connected in series as a group, it being possible for a number of groups formed in this way to be connected in parallel with one another. In principle, other electrical interconnections can also be considered.

The functional conductors can essentially run along a first direction, with the first connecting conductor running at an angle thereto along a second direction. For the course essentially along the first direction, the functional ladders do not have to run straight and parallel to one another. As is known in principle, the individual functional ladders can also run in a wave form or in a zigzag. In addition, adjacent functional ladders can also be at a greater or lesser distance from one another, at least in some areas if they run in a non-parallel manner. Appropriate measures can be used to create contours of the functional textile that deviate from a rectangular shape for specific purposes, for example, and/or to cut out individual areas with functional conductors.

It is preferably provided that the individual functional conductors do not intersect, even if this is harmless per se due to the insulation.

With regard to a possible arrangement of the functional conductors, reference is made to DE 10 2019 103 934 B3, which relates to a knitted spacer section with functional conductors in the form of heating conductors. Possible variations with regard to the arrangement of heating conductors are shown, for example, in FIGS. 4A to 4E and FIG.

In order to contact the functional ladder usually adjacent to an edge of the functional textile with the first connection conductor, this runs at an angle to the individual functional ladders, so that at the crossing points Contact points are formed. Provision can be made here for the second direction to run at a right angle or approximately at a right angle to the first direction. In principle, depending on the cut of the material or the intended use, it can also be expedient if the first connection conductor runs at an angle deviating from a right angle. The first direction and the second direction can then enclose an angle of between 60° and 90°, for example.

In principle, it is also possible for the first connection conductor not to run in a straight line and for example to be arranged along an arc. An extended shape adaptation can take place for certain application purposes through a corresponding course, in which case, however, an increased production effort cannot be ruled out.

According to a preferred development of the invention, it is provided that the functional conductors are connected between the first connecting conductor and a second connecting conductor, the second connecting conductor being arranged at a distance from the first connecting conductor along the first direction. In the context of such an embodiment, the two connection conductors then form an incoming and outgoing line for the functional conductor. When used in a direct current system, in particular in a motor vehicle, one of the two connection conductors can then expediently be assigned to a ground for the entire electrical system.

If, according to a preferred embodiment, a second connection conductor is provided, then all the features and possible variations described in connection with the first connection conductor also apply to the second connection conductor. As already explained at the outset, different types of base textile can be provided within the scope of the invention. The base textile can be formed, for example, in a weaving, knitting or warp-knitting process, but alternatively nonwovens with a certain statistical placement of threads and fibers can also be considered. Basic textiles formed in a weaving, knitting or knitting process can be formed both as a simple textile layer or preferably as a spacer textile with a first flat textile layer, a second flat textile layer and spacer threads connecting the two textile layers.

Regardless of the specific design of the base fabric, it is advantageous with regard to the formation of the functional fabric if the individual functional conductors are led out of a surface of the base fabric in the area of the contact points or lie on the base fabric. The first connection conductor can then be inserted there between the base textile and the functional conductors, the contact points then being produced on the corresponding side of the base textile. Alternatively, it is also possible to cut the base textile before the contact points are produced in such a way that the base textile is removed in the area of the contact points to be formed. Even then, however, it is preferred if the functional conductors are led out of the assigned surface and are thus exposed after a cut.

According to a particularly preferred embodiment of the invention, the base textile is formed by a spacer fabric with a first flat knitted layer, a second flat knitted layer and spacer threads connecting the knitted layers, with the functional conductors being arranged in the first knitted layer. If the base textile is formed by a fleece or a woven fabric, the functional ladder can be introduced into the base textile in a straight line or possibly also in a zigzag.

In the case of a knitted or crocheted fabric, the functional ladder can in principle also form loops like the threads of the base textile, which are usually made of plastic. However, it is preferably provided that the functional ladders are integrated into the base textile without the formation of a stitch. A zigzag configuration, for example, is expedient in this context, as is known in principle from the publications DE 10 2009 013 250 B3, DE 4 239 068 C2, DE 10 2019 103 934 B3 and DE 102019 103 935 A1.

The functional ladder can have a diameter of between 25 μm and 200 μm, for example, particularly preferably between 40 μm and 100 μm. In particular for use for heating purposes, the electrical resistance of the functional conductors can be between 1 Ω (ohm)/m and 280 Ω/m (ohms per meter), preferably between 5 Ω/m and 70 Ω/m.

The diameter specified above refers to the usual circular shape of the wire. In principle, metal wires can also be used whose cross-section is not circular. The cross-sectional area then suitably corresponds to the area of a circular wire with the diameter specified above.

The first connection conductor and, if provided, the second connection conductor have a larger line cross section and can particularly preferably be formed from metal strands, in particular copper strands. The stranded copper wire is essentially formed from copper or a copper alloy. With regard to good conductivity and good processability, the functional conductors and/or the first connecting conductor or the optionally provided second connecting conductor can be formed from copper wire or copper strands, with the copper strands in turn consisting of several copper wires. With copper or a copper alloy as the material for the functional conductors and/or the connection conductors, an additional metallic coating can also be expedient. For example, copper wire can be tinned, in particular hot-dip tinned. The advantage then arises that the tin coating with a typical thickness of about 1 μm to 2 μm protects the underlying copper or the underlying copper alloy better and the material-to-material metal-metal contact provided according to the invention can also be formed more easily . Irrespective of whether they are formed from essentially pure copper or a copper alloy, the corresponding wires or strands are referred to as copper wires or copper strands within the scope of the invention.

In order to create the material-to-material metal-metal contact, the usually significantly different line cross-sections of the functional conductors on the one hand and the first connection conductor or the optionally provided second connection conductor and the resulting different heat conduction must also be taken into account. First of all, it makes sense if the first connection conductor and possibly the second connection conductor are arranged between the functional conductors led out of the base textile and the base textile. Viewed from the outside, the functional conductors then lie above the first connecting conductor or the second connecting conductor, so that a suitable connection can be formed there more easily.

Due to the different size and heat conduction, it can be difficult to create the contact points. Preliminary tests have shown that creating a reliable connection using ultra- sonic welding or laser welding is at least not readily possible.

Against this background, the invention also relates to a method for forming a functional textile which, in particular, has the features described above. Of course, the method described below can also be further specified by the features described above.

According to the method for forming the functional textile, a base textile is provided with a plurality of metallic functional conductors integrated into it and provided with insulation, with at least one metallic connecting conductor provided with insulation being arranged in such a way that it crosses the functional conductors at crossing points, with the Formation of contact points by merely local effects of pressure and temperature, the insulation of the respective functional conductor and the insulation of the connection conductor are at least partially displaced and/or removed, and the respective functional conductor and the connection conductor are connected by a material-locking metal-to-metal connection and where the formed contact points, a separate insulating material is applied.

The contact points are preferably formed one after the other using a thermal welding tool, which can also be referred to as a thermode. Corresponding welding tools are known from the field of electronics.

The control of the individual crossing points to form the contact points can be done manually, computer-aided or fully automatically. If the process is carried out manually, optical aids such as microscopes, magnifying glasses or cameras can be used. Cameras can too be used for a computer-assisted or fully automatic process with a corresponding electronic control.

According to a particularly preferred embodiment of the invention, when using the thermal welding tool, it is provided that the welding tool is heated in a pulsed manner to form the contact points, with the insulation of the associated functional conductor and the connecting conductor being at least partially displaced and/or removed in each case with a first heat pulse and wherein the respective functional lead and the connection lead are then cohesively connected, in particular soldered or welded, with a second heat pulse. Such a two-part method allows the steps, which are different per se in terms of their requirements, to be optimized separately.

The welding tool expediently has a tip which is optimized in terms of its size for the formation of the contact points. The effective area of the tip is expediently so large that the welding tool can be positioned at the crossing points without excessive effort and can sufficiently heat the respective functional lead and the connecting lead that is usually underneath. On the other hand, the effective area should not be too large with regard to process speed, energy efficiency and material protection. The effective area at the tip of the welding tool can be, for example, between 0.1 mm ² and 8 mm ² , in particular between 0.3 mm ² and 3 mm ² .

As already explained above, the insulation material that is provided separately is preferably applied in liquid form to the contact points formed and is bonded by activation. With regard to the formation of the contact points through the local effect of pressure and temperature, a suitable base or counter surface must be provided, especially with spacer textiles, especially if the effect of pressure and temperature takes place by means of the thermal welding tool described above. In addition, the base textile should also be protected from excessive heat exposure.

Against this background, according to a preferred development of the method, it is provided that the functional conductors are led out of the base textile at the contact points, in particular in the form of a spacer fabric, with the first connecting conductor being arranged between the functional conductors and the base textile and then between the connecting conductor and a protective strip is temporarily placed between the base textile to form the contact points. The protective strip can be formed from a temperature-resistant plastic, for example, which is removed again after the contact points have been produced.

Alternatively, however, it is also possible for the base textile to be trimmed before the contact points are produced in such a way that the functional conductors are exposed in the corresponding area.

Finally, the invention also relates to the use of the functional textile described above for heating, in particular the interior of a motor vehicle. It is preferably used with the proviso that the functional textile has between 8 and 40, in particular between 12 and 26 functional conductors as heating conductors which, for example—as explained above—can be connected individually or in pairs in groups in an electrical parallel circuit. The number of 8 to 40 heating conductors is useful for many applications such as the formation of door panels, seats or dashboards, the invention however, is not limited to the specified number. For certain applications, such as heated steering wheels or large roof liners, fewer or more heating conductors can also be provided.

It is particularly preferably provided that a decorative layer is arranged on the base textile, with the functional conductors being arranged on a side of the base textile facing the decorative layer. The decorative layer can be, for example, leather, imitation leather, a film or an upholstery fabric.

If, according to a preferred embodiment of the invention, the base textile is formed by a spacer fabric with a first flat knitted layer, a second flat knitted layer and spacer threads in between, the functional conductors can then be arranged, for example, in the first knitted layer, with the decorative layer then also adjoining the first knitted layer . The decorative layer facing the interior of a motor vehicle, for example, can then be heated very quickly by the functional conductors directly below it with a corresponding current flow, with a good thermal insulating effect being achieved in the opposite direction due to the spacing by means of the spacer threads and the air layer thus provided between the knitted fabric layers .

If, for example, a door lining is equipped with the functional textile for heating purposes, heat is released very quickly to the interior of the motor vehicle, while the heat losses to the outside, for example through a vehicle door, can be limited. Alternatively, the functional textile can also be used in other areas of a motor vehicle, for example in seat surfaces, armrests, dashboards, steering wheels or the like.

It must also be taken into account that with increasing electromobility in corresponding vehicles, the waste heat from a combustion engine cannot be used. Against this background, it is also advantageous if the occupants of a motor vehicle are given a pleasant feeling of warmth by contact heat or radiant heat, without the entire interior having to be excessively heated.

The invention is explained below by way of example with reference to figures.

Show it:

1 is a perspective view of a spacer fabric for the formation of a functional textile Is according to the invention,

FIG. 2 shows the spacer fabric according to FIG. 1 in a plan view,

3 shows the spacer fabric shown in FIGS. 1 and 2 with an additional connection conductor,

4 shows an arrangement for forming the functional textile,

5a to 5d process steps for forming the functional textile.

1 and FIG. 2 show a knitted spacer fabric from which individual knitted spacer sections 1 can be separated. From the individual distance As described in detail below, functional textiles according to the invention are then formed from knitted sections 1 .

The knitted spacer sections 1 have, as usual, a first knitted layer 2 and a second knitted layer 3 which have wales running along a production direction P and rows of stitches running along a transverse direction Q. The knitted fabric layers 2, 3 are connected by spacer threads 4. The structure described corresponds to the usual configuration of a spacer fabric. Except for the functional conductors 6 with insulation 5a described below and connecting conductors 7 with insulation 5b, the spacer fabric is made of plastic threads, in particular based on polyester, with the plastic threads forming a base textile in the sense of the present invention. The functional conductors 6 provided with the insulation 5a are provided in the exemplary embodiment in particular as heating conductors and extend essentially along the production direction P. The functional conductors 6 run in a zigzag in the first knitted fabric layer 2, with the functional conductors 6 themselves not forming any loops and accordingly only inserted into the first layer 2 of knitted fabric. Accordingly, the functional ladder 6 can be arranged easily and with little wear at high positioning speeds.

With regard to the production of the illustrated spacer fabric section, the insulation 5a of the functional conductors 6, which is formed, for example, from an insulating varnish based on polyurethane, is also advantageous.

The functional ladder 6 can be arranged in the first knitted fabric layer 2 according to DE 10 2019 103 934 B3, to which reference is made to the corresponding technical explanations. In order to enable the simplest possible contacting of the functional conductors 6 , the functional conductors 6 are led out of the first knitted fabric layer 2 at connection areas 8 and lie there initially on the first knitted fabric layer 2 .

According to FIG. 3, the connection conductor 7 provided with the insulation 5b is then inserted between the functional conductor 6 and the first knitted fabric layer 2, with a functional textile intended in particular for heating purposes usually having two connection conductors 7. For the purpose of a simple representation, however, the measures provided within the scope of the invention are described below with only one connection conductor 7, with a second connection conductor 7 of the functional textile then being contacted in the same way.

In order to form a base for the production of contact points 9 by pressure and temperature, a protective strip 10 is temporarily placed between the connection conductor 7 shown in FIG. After the formation of the contact points 9, the protective strip 10, which is formed, for example, from a temperature-resistant plastic, is removed again.

Fig. 4 shows an arrangement for forming the contact points 9, with a thermal welding tool 11, which is also referred to as a thermode, applying pressure and temperature locally at the crossing points of the functional conductor 6 with the connecting conductor 7, whereby the insulation 5a of the respective functional conductor 6 and the insulation 5b of the connecting conductor 7 are at least partially displaced and/or removed, and the respective functional conductor 6 and the connecting conductor 7 are connected by an integral metal-to-metal connection. As shown below in connection with FIGS. 5a to 5d, the action of pressure and temperature by means of the welding tool 11 preferably takes place through pulsed heating.

According to FIG. 4, the welding tool 11 has a tip 12, the effective area of the tip 12 being between 0.1 mm ² and 8 mm ² , in particular between 0.3 mm ² and 3 mm ² .

FIG. 5a shows, corresponding to FIG. 3, a sectional representation of one of the functional conductors 6 and the connecting conductor 7 underneath it, with the protective strip 10 being arranged below the connecting conductor 7. FIG. The first knitted fabric layer 2 extends under the protective strip 10.

According to FIG. 5b, only the insulation 5a of the functional lead and the insulation 5b of the connecting lead 7 are initially displaced and/or removed with a first heat pulse, with the functional lead 6 and the connecting lead 7 then merely lying against one another.

According to FIG. 5c, the respective functional conductor 6 and the connecting conductor 7 are connected to one another in a materially bonded manner using a second heat pulse.

According to FIG. 5d, a separate insulating material 13 is applied separately as a liquid to the contact points 9 formed in this way and is preferably bonded by activation, in particular by UV light. Complete electrical insulation then results, with particularly good strength and resilience being achieved by the hardened insulation material 13 on the one hand and the integral metal-to-metal connection between the connection conductor 7 and the functional conductors 6 .

As shown in FIG. 4, the contact points 9 spaced apart from one another along the connecting conductor 7 are formed successively in the manner described, it being possible for the contact points 9 to be generated manually, with computer assistance or fully automatically.

Claims

Patent Claims:

1. Functional textile with a base textile, with several metallic functional conductors (6) provided with insulation (5a) and with at least one metallic first connection conductor (7) provided with insulation (5b), the functional conductors (6) being attached along the first connection conductor (7) spaced contact points (9) are connected to the first connection conductor (7), d a r c h g e k e n n z e c h n e t that at the contact points (9) the insulation (5a) of the functional conductor (6) and the insulation (5b) of the first connection conductor ( 7) are at least partially displaced and/or removed and that the functional conductor (6) and the first connection conductor (7) are connected at the contact points (9) by a material-locking metal-to-metal connection.

2. Functional textile according to claim 1, characterized in that an insulation material (13) is applied separately to the contact points (9).

3. Functional textile according to claim 2, characterized in that the insulating material (13) differs materially from the insulation (5a) of the functional conductor (6) and the insulation (5b) of the first connection conductor (7).

4. Functional textile according to one of Claims 1 to 3, characterized in that the functional conductors (6) essentially run along a first direction, with the first connection conductor (7) running at an angle thereto along a second direction.

5. Functional textile according to claim 4, characterized in that the functional conductors (6) are connected between the first connecting conductor (7) and a second connecting conductor, the second connecting conductor being arranged at a distance from the first connecting conductor (7) along the first direction .

6. Functional textile according to one of Claims 1 to 5, characterized in that the base textile is a knitted spacer fabric with a first flat knitted fabric layer (2), a second flat knitted fabric layer (3) and spacer threads (4) connecting the knitted fabric layers, with the functional conductors (6 ) are arranged at least in sections in the first knitted fabric layer (2).

7. Functional textile according to claim 6, characterized in that the functional ladder (6) are integrated into the base textile without stitch formation.

8. Functional textile according to one of claims 1 to 7, characterized in that the insulation (5a) of the functional conductor (6) is formed by an insulating varnish.

9. Functional textile according to one of claims 1 to 8, characterized in that the first connection conductor (7) is formed by metal strands, which has a coating of thermoplastic material as insulation (5b).

10. Functional textile according to one of claims 1 to 9, characterized in that the first connecting conductor (7) is arranged on the base textile, the functional conductors (6) being led out of the base textile in the region of the first connecting conductor (7).

11. Functional textile according to one of claims 1 to 10, characterized in that the functional conductors (6) and/or the first connection conductor (7) are essentially made of copper or a copper alloy, in particular tinned copper wire.

12. A method for forming a functional textile, in particular according to one of claims 1 to 11, a. the base textile being provided with a plurality of metallic functional conductors (6) bound into it and provided with insulation (5a) b. at least one metallic connection conductor (7) provided with insulation (5b) being arranged in such a way that it crosses the functional conductors (6) at crossing points c. wherein the insulation (5a) of the respective functional conductor (6) and the insulation (5b) of the connection conductor (7) are at least partially displaced and/or removed at the crossing points to form contact points (9) by only local exposure to pressure and temperature, and the respective functional lead (6) and the connection lead (7) are connected by a material-locking metal-to-metal connection and d. a separate insulating material (13) being applied to the contact points formed.

13. The method according to claim 12, wherein the contact points (9) are successively formed with a thermal welding tool (11).

14. The method according to claim 13, wherein the welding tool (11) for the formation of the contact points (9) is heated in a pulsed manner, with the insulation (5a) of the associated functional conductor (6) and the insulation (5b) of the connecting conductor each being heated with a first heat pulse (7) at least partially displaced

and/or removed and with the respective functional lead (6) and the connection lead (7) being cohesively connected with a second heat pulse.

15. The method according to claim 13 or 14, wherein the welding tool (11) has a tip (12) with an area of between 0.1 mm ² and 8 mm ² , in particular between 0.3 mm ² and 3 mm ² .

16. The method according to any one of claims 12 to 15, wherein the separate insulating material (13) is applied in liquid form to the formed contact points (9) and is bound by activation.

17. The method according to any one of claims 12 to 16, wherein the functional conductors (6) are led out of the base textile at the contact points (9), the first connecting conductor (7) being arranged between the functional conductors (6) and the base textile and wherein between a protective strip (10) is temporarily interposed between the first connection conductor (7) and the base textile to form the contact points (9).

18. Use of a functional textile according to one of claims 1 to 11 for heating, in particular the interior of a motor vehicle.

19. Use according to claim 18, with the proviso that a decorative layer is arranged on the base textile, wherein the functional conductors (6) are arranged on a side of the base textile facing the decorative layer.