EP2806709B1 - Electrically conducting surface - Google Patents

Description

The invention relates to an electrically conductive sheet according to the preamble of claim 1. In particular, as a heated surfaces such as seat heaters include electrically conductive fabrics nowadays in many motor vehicles to the standard equipment.

In addition to electrical heating systems that are not in a solid composite with the overlying decorative and seat of z. As textile material, leather or synthetic leather are also directly heatable decorative materials used, which have an integrated electric heating function.

In addition to the application as heating, such elements can of course also be used as sensors, switches, antennas, etc.

In all cases, however, it is necessary to produce an electrical contact to a voltage source. In particular, when high currents must be transported as in the case of a heating function, the accuracy of the contact comes between lead electrodes and the electrically heatable sheet material a crucial importance, over the entire useful life of the heater.

To realize the contacting of heating elements a variety of ways have been proposed and realized.

For example, contacts are known which include sewing the contact electrodes to the heating elements. This is eg in WO 02/052899 A1 described. Here we disclose a surface heating with a heating layer of a flexible, conductive plastic, which is applied to a likewise flexible carrier made of eg fabric, non-woven or non-woven fabric. In this case, the contact ends of power supply wires are sewn or glued to the heating layer, may consist of silver or copper wires and be completely surrounded by the electrically conductive plastic.

It is also proposed here to introduce the electrical connection electrodes already in the textile support surface for the heating layer. This has the disadvantage that the position of the contact electrodes can not be varied. Also, all contacting methods involving stitching of the terminal electrodes have the disadvantage that they are only suitable for decorative materials, such as those used in automotive interiors or other seating, when the visible seam on the surface as a desired decorative or design element can be used. However, this is desirable only in the rarest cases.

This type of contacting also has the disadvantage that the intimacy of the contact determines the contact resistance. If the seam is not performed firmly enough or the seams loosen due to damage or thread fatigue, sufficient conductivity is no longer present in the contact area and the heating effect of the fabric is weakened or lost.

In particular, under dynamic and climatic loads over a long period, as is the case for example in the seating area of an automobile, the durability of a seat heating can not be guaranteed.

The stitching also has the disadvantage that locally under the seam, a high pressure with a low contact resistance arises, whereas between the seams or seams a lower pressure with a much higher contact resistance, since the electrode is pressed less strongly against the conductive coating , This results in an unevenness of the electrical contact resistance along the electrode, so that this also has an effect on the homogeneity of the heating power of the textile fabric.

In the DE 10 2007 042 644 A1 describes the contacting of surface area as a band running electrodes to an electrically conductive, flexible sheet by means of one or more seams. Again, the above-mentioned disadvantages occur.

The GB 1,069,592 discloses an electrical heating element, wherein a flexible textile material coated with an electrically conductive material is described. The electrically conductive coating material may be a polymer material with soot particles. The electrodes are sewn so that there is a secure contact with the conductive coating. Here, however, the disadvantages described above can be expected as well.

Also known is the bonding of contact electrodes. Although the bonding of contact electrodes with conductive plastics allows any positioning of the contact electrodes, but the adhesive proposed in the application, for example, with a high proportion of graphite are less flexible and hardly dynamic loadable. Other commercially available electrical contact adhesives are usually based on highly crosslinking polymers such as epoxy resins, which indeed allow an intimate electrical connection, but can not withstand dynamic loads due to the chemical crosslinking.

Furthermore, an electrical contact by crimping, riveting or clamping (as in the PCT / EP / 2010/058213 described) realize. In these methods, the contact point is, for example, artificial leathers visible on the opposite decorative surface.

The DE 4233118 proposes to avoid high contact resistance between an electrically conductive tissue and the contact wires before an intimate connection to the contact wires by weaving into the tissue, so that a plurality of individual contact points results. However, the transition of the fed via the woven contact wires current into the electrically conductive surface is not homogeneous due to the large number of contact points. In addition, the position of the connection electrodes is determined by weaving the contact wires.

In principle not visible on the surface are also contacts which include a soldering of the connection electrodes on the electrically conductive sheet. So that beats DE 202005010011 U1 to reinforce, electrically conductive, coated fabrics in the connection area targeted by a metallic layer in order to establish a stable solder joint there.

Such solder joints have, as well as the bonding of the terminal electrodes with a commercially available bonding adhesive, which is cured by crosslinking, the disadvantage that the resulting compound in good design of the contact is indeed intimately, but can hardly withstand durable flexible loads due to the rigidity ,

The conductive contacting adhesives described above generally contain as electrically conductive filler metal particles z. Based on silver, copper or nickel such as Master Bond EP76M, Delo Dualbond IC 343 from Delo Industrial Adhesives, Loctite 3880 from Henkel. Such adhesives are usually cured by cross-linking.

Glued band-shaped electrodes are also known, but they do not solve the problem of permanently flexible contact per se, since the known adhesives with which the band electrodes are fixed on the conductive surface are not permanently flexible as described above.

Such band electrodes are used for example in the EP 0 057 284 A2 disclosed. Described are electrical control contacts made of metallized textile fabrics in ribbon form, which can be connected to surface heating by attaching, gluing or sewing.

US 2008/0010815 A1 discloses an electrically conductive sheet according to the preamble of main claim 1.

EP 2 457 944 A1 discloses a polymer blend comprising three-dimensionally branched conductive dendritic particles.

For the invention therefore had the task of a flexible and stretchable electrically conductive flexible sheet, which is used as surface or decorative surface material to contact with electrical leads without high contact resistance and without the visible surface of the sheet is visually impaired by the contact. In addition, the object of the contacting against stresses, such as may occur in the automotive interior to make insensitive, so for example insensitive to hydrolysis susceptibility, insensitive to heat loads up to 120 ° C, and insensitive to dynamic loads such as occur on a seat , Furthermore, the object was to provide a contact in which occur even at high currents and over a longer period of time no irregularities in the contact resistance to the electrically conductive surface, especially not after prolonged heat and / or moisture or prolonged dynamic loads. Such irregularities are manifested in particular when high currents flow through local heating ("hot spots"), which can lead to the burning or interruption of the electrical line.

In addition, during the contacting, the use of solvents and the application of high temperatures, which could damage the carrier substrate of the electrically conductive coating, should be avoided.

Furthermore, the object was to implement a contacting method that allows any positioning of the contact electrodes on the electrically conductive surface.

This object is achieved by the features of the main claim. Further advantageous embodiments are disclosed in the subclaims.

In this case, the conductive connection between the electrode and the layer of conductive plastic material by an electrically conductive, curable polymeric paste having three-dimensionally branched conductive particles, preferably dendritic particles, wherein the electrode conductive filaments, so preferably wires, fibers, wires or strands , wherein the filaments are arranged and spaced relative to each other and the viscosity of the paste is formed so that the paste surrounds or penetrates the electrode embedding and / or enclosing the filaments and curing or bonded to the layer of conductive plastic material.

Dendritic here means "present in the form of dendrites", whereby the term "dendrite" is again derived from the Greek word "dendron" for tree. Dendrites are therefore tree-shaped to moss-shaped structures (see also Römpp-ChemieLexikon Online, Version 3.9, 201 0).

It has surprisingly been found that the use of this per se known electrically curable, curable polymeric paste as an electrode penetrating and the latter in the form of a polymer matrix in the medium einbindendes medium a uniform, highly resilient, also applicable for seat heaters permanently flexible and resistant contact with a corresponding layer of electrically conductive plastic material, as was previously unknown in the prior art.

An advantageous development is that the layer of electrically conductive plastic material identifies conductive filaments, preferably conductive textiles with metal threads or metal-coated threads or carbon fibers.

An inventive design is that the layer of electrically conductive plastic material semiconductor or metal particles or filled with semiconductors or metal fillers, such as micro glass beads, hollow glass microspheres, glass fibers, copper powder, copper dendrites, copper platelets, etc., or mixtures thereof. These additions increase the conductivity without impeding the required penetration into the electrode and penetration of the electrode during application.

A further advantageous embodiment is that the electrically conductive paste is not crosslinked or is added only in a small proportion of less than wt. 2% with a crosslinker. This facilitates application to or impregnation of the electrode prior to curing, and the electrode construction or structure is fully integrated into the resulting matrix.

A further advantageous embodiment consists in that the planar electrode is provided with a heat-activatable thermoplastic polymer adhesive. This achieves the advantage that the planar electrode prefixed on the electrically conductive substrate and thus the conductive paste can be applied safely.

The flexible and stretchable electrically conductive layer on the film, the textile or artificial leather, to which the electrodes are connected with the compound according to the invention includes, for example, conductive textiles with metal threads or wires, metal-coated threads, filaments covered with metal filaments, metal filaments, Carbon fibers, carbon filaments or even partially or fully printed, coated textiles or films. Such films are typically coated with conductive polymers that are either intrinsically conductive, such as PEDOT-PSS, or the electrically conductive particles, such as carbon black, CNTs, graphene, carbon fibers, semiconductor or metal particles. Such films can also be mixed with semiconductors or metal Have fillers such as micro glass beads, hollow glass microspheres, glass fibers, copper powder, copper dendrites, copper platelets, etc. or be occupied with mixtures thereof. Also, such films may be formed as metallic, metallized or laminated with metal foil or other conductive material films.

Through the use of ribbon-shaped connection electrodes, wherein the conductive strands, wires or fibers in the number and cross-section according to DIN VDE 0100, Part 520 are designed so that the currents flowing in the later application can be easily absorbed without heating, can achieve a safe power supply.

Due to the nature of the invention, the terminal electrodes can be positioned almost arbitrarily on the electrically conductive surface. Preferably but not absolutely necessary is a parallel arrangement of the electrodes. The intimate connection of the band-shaped preferably extensible electrode to the electrically conductive surface occurs only by impregnation of the textile electrode with an electrically conductive polymeric paste and the subsequent drying.

As stated, it can be advantageous for the connection electrodes to contain a heat-activatable thermoplastic polymer adhesive so that they can be prefixed to the electrically conductive base.

• 345 g einer wässrigen aliphatischen Polyester-Polyurethandispersion mit 50 % Festkörpergehalt werden unter Rühren mit einem Dissolver bei 800 Umdrehungen/Minute homogen gemischt mit
  1. i. 6 g eines assoziativ wirksamen Verdickers,
  2. ii. 258,75 g von feinteiligen Füllstoffpartikel mit dendritischer Form auf Basis von oberflächlich mit Silber beschichtetem Kupfer, und
  3. iii. 86,25 g von feinteiligen Partikeln mit sphärischer oder länglicher Gestalt
  4. iv. 5 g eines Isocyanatvernetzers auf Basis von trimeren Hexamethylendiisocyanat mit 21,8 % Gehalt an freien Isocyanatgruppen Optional zur Einstellung der Viskosität werden im genannten Beispiel 215 g destilliertes Wasser zusätzlich zugegeben,
• wobei folgende Rohstoffe verwendet werden:
  1. i. als dendritische Leitfahigkeitspartikel: silberbeschichtete Kupferpartikel mit dendritischer Gestalt mit einem durchschnittlichen Partikeldurchmesser von 35 um und einem Silbergehalt von 18 %,

als feinteilige sphärische Partikel: silberbeschichtete Glashohlkugeln mit einem durchschnittlichen Partikeldurchmesser von 44 µm und einem , Silbergehalt von 33 %.All of these advantages can be enhanced when an electrically conductive, curable polymeric paste is used to impregnate an electrode and bond it to an electrically conductive plastic material made as follows:

• 345 g of an aqueous aliphatic polyester-polyurethane dispersion with 50% solids content are homogeneously mixed with stirring with a dissolver at 800 revolutions / minute
  1. i. 6 g of an associative thickener,
  2. ii. 258.75 g of finely divided filler particles with dendritic form based on superficially silver-coated copper, and
  3. iii. 86.25 g of finely divided particles of spherical or oblong shape
  4. iv. 5 g of an isocyanate crosslinker based on trimeric hexamethylene diisocyanate having a content of free isocyanate groups of 21.8% Optionally, in order to adjust the viscosity, 215 g of distilled water are additionally added in the abovementioned example,
• the following raw materials are used:
  1. i. as dendritic conductivity particles: silver-coated copper particles of dendritic form having an average particle diameter of 35 μm and a silver content of 18%,

as finely divided spherical particles: silver-coated glass hollow spheres with an average particle diameter of 44 μm and a, silver content of 33%.

Reference recipe 1:

1000 g of Impranil DLU (Bayer Material Science, 60% solids content) are processed to a homogeneous paste with conductivity black 150 g of Ensaco 250 G (Timcal) using a paddle stirrer

Reference recipe 2:

Delo-Dualbond IC 343 from Delo Industrie Klebstoffe (silver-filled thermosetting Adhesive)

Reference recipe 3:

Loctite 3880 from Henkel (silver-filled thermosetting epoxy adhesive)

Polymer Paste Example Formulation 1:

• 345 g einer wässrigen aliphatischen Polyester-Polyurethandispersion (mit 50 % Festkörpergehalt) werden mit 6 g eines assoziativ wirksamen Verdickers, 258,75 g von feinteiligen Füllstoffpartikel mit dendritischer Form auf Basis von oberflächlich mit Silber beschichtetem Kupfer und 86,25 g von feinteiligen Partikeln mit sphärischer oder länglicher Gestalt und 5 g eines Isocyanatvernetzers auf Basis von trimeren Hexamethylendiisocyanat mit 21,8 % Gehalt an freien Isocyanatgruppen werden unter Rühren mit einem Dissolver bei 800 Umdrehungen/Minute homogen vermischt. Optional zur Einstellung der Viskosität werden im genannten Beispiel 215 g destilliertes Wasser zusätzlich zugegeben.

The preparation of the coating composition can be described as follows:

• 345 g of an aqueous aliphatic polyester polyurethane dispersion (with 50% solids content) with 6 g of an associative thickener, 258.75 g of finely divided filler particles with dendritic form based on superficially silver-coated copper and 86.25 g of finely divided particles spherical or oblong shape and 5 g of an isocyanate crosslinker based on trimeric hexamethylene diisocyanate with 21.8% content of free isocyanate groups are homogeneously mixed with stirring with a dissolver at 800 revolutions / minute. Optionally, in order to adjust the viscosity, 215 g of distilled water are additionally added in the abovementioned example.

• Dendritische Leitfahigkeitspartikel: silberbeschichtete Kupferpartikel mit dendritischer Gestalt (durchschnittlicher Partikeldurchmesser = 35 um, Silbergehalt 18 %) = Conduct-O-Fil, SC500P18, Fa. Potters Industries Inc.
• silberbeschichtete Glashohlkugeln (durchschnittlicher Partikeldurchmesser = 44 um, Silbergehalt 33 %) = Conduct-O-Fil, SH230S33, Fa. Potters Industries Inc.

The following raw materials are used:

• Dendritic conductivity particles: silver-coated copper particles of dendritic shape (average particle diameter = 35 μm, silver content 18%) = Conduct-O-Fil, SC500P18, Potters Industries Inc.
• silver-coated glass bubbles (average particle diameter = 44 μm, silver content 33%) = Conduct-O-Fil, SH230S33, from Potters Industries Inc.

The following Table 1 shows the advantages of the polymer paste on the basis of the comparison of the known reference recipes 1 to 3 for electrical contacting compared to an example recipe. For contacting, the contact band Art. 3750 from A.Mohr was used in all cases.

For this purpose, a synthetic leather based on polyurethane was used with a polyester fabric carrier, which partially on the textile side in a grid-like arrangement with a electrically conductive coating is provided, which can be used when applying an electrical voltage as resistance heating. DIN A 5 samples of this material were used, which are each provided with the contact bands on both longitudinal sides.

For this purpose, the contact bands, which are provided with a hotmelt adhesive, were prefixed with an iron and subsequently impregnated with the conductive pastes over the entire electrode length by means of a pipette, so that ideally an intimate electrically conductive connection between electrode bands and the resistance heating arises.

The conductive paste (adhesive) was then thermally cured in an oven at 80 ° C.

To test the patterns under current load, a DC voltage of 6 volts was applied. Table 1: Application properties of conductive adhesives unsupported After hydrolysis storage (7 days at 70 ° C and 95-100% humidity) After 200 h heat storage (at 120 °) Viscosity [mPas] Adhesive curing temperature [° C] Heating the contact bands at 6 V Temperature of the resistance heating after 10 min 6 volts Heating the contact bands at 6 V Heating of the contact bands at 6 V Reference recipe 1 > 200000 80 (4 minutes) significant warming 46 ° C significant warming significant warming and hotspots Reference recipe 2 30000 80 (30 min) no warming 46 ° C no warming no warming 100 (10 minutes) Reference recipe 3 50000-150000 125 (10 minutes) no warming 47 ° C no warming no warming 175 (3 min) example recipe 1000 - 10000 80 (4 minutes) no warming 48 ° C no warming no warming

Shown here are only solvent-free electrically conductive adhesive systems, as the use of solvents in such applications is undesirable under toxicological and occupational hygiene aspects.

The relatively high processing viscosities of the reference adhesive systems of 30,000 -> 200,000 mPAs mean that impregnation of the conductive textile tapes is not ideally possible because the adhesive is difficult to penetrate the textile structure and does not completely cover the conductive strands or cables become. In addition, air is trapped during the drying process, which leads to non-conductive areas in the contact area and increases the risk of hotspots, since the current transfer from the contact strip to the electrically conductive heating surface no longer takes place in a homogeneous manner.

Furthermore, it can be seen that a combination of low adhesive curing temperature and short curing time of the adhesive is ensured only by the reference formulation 1 and the example formulation. Such a combination is necessary to protect the heating substrate, which may be in particular a synthetic leather, and at the same time represent an economical contacting process.

In order to avoid hotspots and to ensure a current transport from the contact strips to the electrically conductive surface with a low contact resistance, the impregnation must be very homogeneous and resistant to prolonged heat load (in this case storage of the sample for 200 h at 120 ° C) or prolonged exposure to moist heat (here storage of the sample at 70 ° C and 95-100% humidity over 7 days). Although this is true in the case of the reference recipes 2 and 3 and in the example recipe but not in the case of the highly viscous reference formula 1.

The combination of freedom from solvents, low viscosity, short curing time at comparatively low temperatures, homogeneous and aging-resistant contacting can only be represented by the use of the example formulation.

Table 2 demonstrates another advantage of the polymer paste. For this purpose, a conductivity band (contact band Art. 3750 from A.Mohr) was glued centrally in longitudinal direction onto the electrically conductive surface of a test specimen (50 × 100 mm) using the 3 reference and the example recipe. The contacting takes place as in the manner described above. Thereafter, the test specimens were tested in a De Mattia tester (DIN 53522) and assessed after 10000 flexes. Table 2: Contact between electrode tape and electrically conductive surface (visual assessment) according to De Mattia test (DIN 53522) 10000 cycles Electrode condition at the clamping Electrode condition at the kink site Reference recipe 1 Breakage of all strands Strands partially broken Reference recipe 2 Breakage of all strands Strands partially broken Reference recipe 3 Breakage of all strands Strands partially broken Inventive sample formulation Strands undamaged Strands undamaged

It is noticeable that after the test, in particular at the sharp kink points of the sample clamping on samples with the reference formulations, all conductive strands are completely broken, whereas the strands on the sample with the example formulation after the test are undamaged. Even with the less sharp creases in the center of the sample, this difference is visible, though not in such a pronounced way.

• Vorteilhafterweise wird ein Basispolymer auf wässriger Basis (Polyurethan- oder Acrylat-Dispersion) oder eine lösungsmittelfreie Polyurethan High-Solid-Rezeptur eingesetzt. Es können aber auch andere flüssige oder pastöse Systeme wie PVC-Plastisole oder in Lösungsmittel gelöste Polymere eingesetzt werden. Auch der Einsatz von Thermoplasten im geschmolzenen Zustand ist möglich.
• Vorteilhafterweise sind die leitfähigen dreidimensional verzweigten dendritischen Leitfähigkeitspartikel mit Edelmetall (Silber) beschichtete Kupferdendrite. Verwendet werden können auch mit Nickel beschichtete Kupferdendrite.
• Vorteilhafterweise werden als elektrische Anschlusselektroden dehnfähige textile Bandelektroden mit integrierten metallischen Litzen (wie von der Fa. A.Mohr) verwendet. Es können aber auch Anschlusseelektroden auf Basis von Kohlefasern, auf Basis von Kohlefasern in Verbindung mit anderen metallischen Kabel und Litzen, auf Basis von metallischen Litzen, Kabeln oder Bändern oder auf Basis anderer textiler Leiterbahnen, Gewebe, Kordeln etc., die elektrisch leitfähige Fadenmaterialien, Kabel oder Litzen enthalten, verwendet werden.
• Vorteilhafterweise wird die Viskosität der elektrisch leitfähigen Kontaktierungspaste in einem Viskositätsbereich von 500 - 20000 mPas eingestellt, um insbesondere bei textilen Leitfähigkeitsbändern eine optimale Imprägnierung und Ummantelung der leitfähigen Adern zu erreichen. Insbesondere dann, wenn die Elektroden auf der leitfähigen Kontaktpaste nur aufliegen und/oder nur teilweise einsinken sollen, können auch höhere Viskositäten vorteilhaft sein.

As a result, in particular the advantageous behavior under dynamic loads when used on flexible substrates such as a synthetic leather is demonstrated.

• Advantageously, a base polymer based on water (polyurethane or acrylate dispersion) or a solvent-free polyurethane high-solid formulation is used. However, it is also possible to use other liquid or pasty systems, such as PVC plastisols or polymers dissolved in solvents. The use of thermoplastics in the molten state is possible.
• Advantageously, the conductive three-dimensionally branched dendritic conductivity particles are noble metal (silver) coated copper dendrites. It is also possible to use nickel-coated copper dendrites.
• Advantageously, stretchable textile belt electrodes with integrated metallic strands (such as from A.Mohr) are used as electrical connection electrodes. However, it is also possible to use connection electrodes based on carbon fibers, based on carbon fibers in conjunction with other metallic cables and strands, on the basis of metallic strands, cables or tapes or on the basis of other textile conductors, fabrics, cords, etc., the electrically conductive thread materials, Cables or strands are used.
• Advantageously, the viscosity of the electrically conductive contacting paste is adjusted in a viscosity range of 500-20000 mPas, in order to achieve optimal impregnation and sheathing of the conductive wires, in particular in the case of textile conductivity bands. In particular, when the electrodes only rest on the conductive contact paste and / or only partially sink in, higher viscosities may also be advantageous.

• Durch die Verwendung der flexiblen leitfähigen Elektrodenbändern zusammen mit der beschriebenen Leitfähigkeitspaste können flexible und auch dehnfähige elektrisch leitfähige Flächengebilde elektrisch kontaktiert werden, ohne dass auch bei hohen Strömen, wie sie beispielsweise bei Sitzheizungsanwendungen fließen, hohe Übergangswiderstände zwischen Elektroden und elektrisch leitfähiger Fläche auftreten.
• Auf der der elektrisch leitfähigen Fläche gegenüberliegenden Seite der Folie/des Flächengebildes sind die Positionen der Elektroden nicht sichtbar. So ist diese Methode insbesondere auch für elektrisch leitfähige Flächengebilde geeignet, die eine sichtbare (Dekor-)Oberfläche enthalten, deren Eindruck nicht durch die Sichtbarkeit der Elektrodenanschlüsse gestört werden soll.
• Die beschriebene Art der Kontaktierung ist widerstandsfähig gegen dynamische Belastungen und gegen Alterungs- und Klimaeinflüsse (Hydrolyseunempfindlichkeit)
• Der Übergangswiderstand zwischen den Anschlusselektroden und der elektrisch leitfähigen Fläche bleibt auch beim Fließen hoher Ströme über lange Zeit insbesondere auch nach Wärmebelastung und nach Hydrolyselagerung so niedrig, dass keine lokalen Erwärmungen ("hot spots") auftreten.
• Es können nicht nur die vorteilhaften textilen Elektrodenbänder zur Kontaktierung verwendet werden, sondern auch alle anderen denkbaren elektrisch leitfähigen Kontaktelektroden wie Kabel und Litzen auf Basis von Metallen (beispielsweise Kupfer, Silber, Edelstahl, verzinntes, versilbertes oder vergoldetes Kupfer), auf Basis von elektrisch leitfähigen Fäden (beispielsweise galvanisierte oder mit Metallfäden umgebene textile Fasern oder Kohlefasern), auf Basis von Metallbändern oder metallisierten bandförmigen Folien oder auf Basis von Elektroden, die elektrisch leitfähige Polymere enthalten.
• Die Kontaktierung kann bei Temperaturen < 100°C durchgeführt werden, ohne dass die beschriebene Kleberzusammensetzung wie bei anderen Klebersystemen üblich bei deutlich höheren Temperaturen ausgehärtet werden muss. Die Methode ist somit besonders schonend für das zu kontaktierende Substrat und die Anschlusselektroden.
• Gesundheitsschädliche und umweltgefährdende Lösungsmittel können bei der Kontaktierung vermieden werden, indem insbesondere als Basis für die leitfähige Paste eine wässrige (Polyurethan)-Dispersion oder eine Polyurethan High-Solid-Rezeptur verwendet wird.
• Die Anschlusselektroden können gemäß der beschriebenen Methode beliebig auf der elektrisch leitfähigen Fläche positioniert werden. Eine vorherige Festlegung beispielsweise durch aufgedruckte Positionen mit leitfähigem Lack oder ein flächig mit leitfähigem Material abgedeckter Untergrund auf der leitfähigen Fläche sind somit nicht notwendig.

• Bei Verwendung von wässrigen Dispersionen kann die Viskosität der elektrisch leitfähigen Paste durch Zugabe von Wasser und/oder Verdickern in einem sehr großen Rahmen je nach gewünschter Applikation variiert werden.
• Die Lösung kann sowohl für Anwendungen mit hohen Strömen wie Sitzheizungen als auch mit niedrigen Strömen wie Sensoranwendungen verwendet werden.
• Die Lösung ist insbesondere auch für elektrisch leitfähige Flächengebilde geeignet, die nicht vollständig flächig leitend sind, wie beispielsweise Flächengebilde, die mit einem elektrisch leitfähigen Druck versehen sind, der die nicht leitende Fläche nur partiell abdeckt oder für nichtleitende textile Flächengebilde, die elektrisch leitfähige Gebilde enthalten.

Advantages of the invention are therefore summarized once again in particular in the following manner:

• By using the flexible conductive electrode strips together with the conductivity paste described, flexible and also extensible electrically conductive structures can be electrically contacted without high contact resistances between the electrodes and the electrically conductive surface even at high currents, such as those used in seat heating applications.
• On the opposite side of the electrically conductive surface of the film / sheet, the positions of the electrodes are not visible. Thus, this method is particularly suitable for electrically conductive fabrics that contain a visible (decorative) surface, the impression should not be disturbed by the visibility of the electrode terminals.
• The type of contacting described is resistant to dynamic loads and to aging and climatic influences (hydrolysis insensitivity)
• The contact resistance between the terminal electrodes and the electrically conductive surface remains so low even when flowing high currents for a long time, especially after heat load and after storage of hydrolysis, that no local heating ("hot spots") occur.
• Not only the advantageous textile electrode tapes for contacting can be used, but also all other conceivable electrically conductive contact electrodes such as cables and strands based on metals (for example copper, silver, stainless steel, tin-plated, silver-plated or gold-plated copper), based on electrically conductive Threads (for example galvanized or metal fibers surrounded by textile fibers or carbon fibers), based on metal strips or metallized band-shaped films or on the basis of electrodes containing electrically conductive polymers.
• The contacting can be carried out at temperatures <100 ° C, without the adhesive composition described as usual in other adhesive systems must be cured at significantly higher temperatures. The method is therefore particularly gentle on the substrate to be contacted and the connection electrodes.
• Harmful and environmentally hazardous solvents can be avoided during the contacting, in particular by using an aqueous (polyurethane) dispersion or a polyurethane high-solids formulation as the basis for the conductive paste.
• The connection electrodes can be arbitrarily positioned on the electrically conductive surface according to the described method. A prior determination For example, by printed positions with conductive paint or a surface covered with conductive material substrate on the conductive surface are therefore not necessary.

• When using aqueous dispersions, the viscosity of the electrically conductive paste can be varied by adding water and / or thickeners in a very large range depending on the desired application.
• The solution can be used for both high current applications such as seat heaters and low currents such as sensor applications.
• The solution is particularly suitable for electrically conductive fabrics that are not completely planar conductive, such as sheets, which are provided with an electrically conductive pressure that covers the non-conductive surface only partially or for non-conductive textile fabrics containing electrically conductive structures ,

Incidentally, the described solution can be used for contacting on flexible as well as on rigid electrically conductive substrates.

• Verwendung zur Kontaktierung bzw. Verklebung von elektronischen Bauteilen wie LEDs, Transistoren, RFID-Chips, Kondensatoren, ICs, Mikroprozessoren etc.
• Verwendung zur Kontaktierung in Photovoltaikanwendungen
• Verwendung zur Kontaktierung für flexible und starre Displays und touch screens
• Verwendung zur Kontaktierung in starren oder flexiblen OLED-Anwendungen
• Verwendung zur Kontaktierung von Sensoren, Diagnosegeräten oder Messfühlern auf flexiblen oder starren Untergründen
• Verwendung zur Kontaktierung jeglicher Art von Heiz- und Kühlanwendungen auf elektrischer Basis wie elektrische Widerstandsheizungen oder Kühlelemente mit Peltierelementen (im Bau-, Wohn- und Industriebereich, In Bekleidungsanwendungen, in Sitz- und Liegemöbeln, in Sportgeräten etc.)
• Verwendung für Kontaktierungsanwendungen in starren und flexiblen Batterien
• Verwendung zur Kontaktierung in elektromagnetischen Anwendungen
• Verwendung zur flexiblen Kontaktierung von beweglichen elektrisch leitfähigen oder elektronischen Komponenten.

So further following applications are conceivable:

• Use for contacting or bonding of electronic components such as LEDs, transistors, RFID chips, capacitors, ICs, microprocessors, etc.
• Use for contacting in photovoltaic applications
• Use for contacting for flexible and rigid displays and touch screens
• Use for contacting in rigid or flexible OLED applications
• Use for contacting sensors, diagnostic devices or probes on flexible or rigid surfaces
• Use for contacting any kind of electrical heating and cooling applications such as electrical resistance heaters or cooling elements with Peltier elements (in the construction, residential and industrial sectors, in clothing applications, in sitting and lying furniture, in sports equipment, etc.)
• Use for contacting applications in rigid and flexible batteries
• Use for contacting in electromagnetic applications
• Use for flexible contacting of moving electrically conductive or electronic components.

Fig. 1

eine erfindungsgemäße Verbindung schematisch

Fig. 2

einen Querschnitt des Aufbaus der in Fig. 1 gezeigten erfindungsgemäßen Verbindung

Fig. 3

einen Querschnitt einer erfindungsgemäßen Verbindung mit einem textilen Elektrodenband

Fig. 4

einen Querschnitt einer erfindungsgemäßen Verbindung mit einer bandförmigen flachen Elektrode

Reference to an embodiment, the invention will be explained in more detail. Show it

Fig. 1

a compound of the invention schematically

Fig. 2

a cross section of the structure of in Fig. 1 shown compound of the invention

Fig. 3

a cross section of a compound of the invention with a textile electrode tape

Fig. 4

a cross section of a compound according to the invention with a ribbon-shaped flat electrode

The Fig. 1 schematically shows an electrically conductive sheet 1 in the form of a film or a flexible artificial leather, which is connected according to the invention with multi-core electrode strips. The flexible synthetic leather or the film is printed on the back with an electrically conductive pattern 2 in rhombic structure, ie with a grid-shaped arrangement of conductive tracks or strips. The electrically conductive sheet 1 or the film is provided with two parallel textile-based electrodes 3 each having a plurality of conductive wires, wherein the wires of the electrodes are impregnated with the electrically conductive paste and connected to the grid structure, so that the electrically conductive wires completely from the electrically conductive paste are sheathed.

Fig. 2 schematically shows a cross section of the structure of in Fig. 1 It can be clearly seen here that the electrically conductive sheet 1 or film shown here consists of a decorative layer 4, an intermediate layer 5, and structured with a grain, visible from the outside and a textile layer / carrier layer 6.

The textile layer 6 is provided on the back with an electrically conductive pressure, namely the in Fig. 1 illustrated electrically conductive pattern 2 in diamond structure, ie with a grid-shaped arrangement of conductive tracks, whereby the textile layer 6 is only partially covered.

A textile contact band with electrically conductive wires, here formed as metal filaments 7, is so impregnated with an electrically conductive paste 8, that the metal filaments 7 completely encased by the paste 8 and the paste 8 with the on the back of the textile layer 6 and thus On the back of the electrically conductive sheet 1 printed circuit traces of the pattern 2 are conductively connected.

In this case, the conductive paste contains the dendritic conductivity particles according to the invention, which ensures the subsequent flexibility of the electrode connections.

Further possible embodiments of the solution according to the invention are illustrated by the drawings 3 and 4.

In particular, when the conductive paste is to be used mainly for electrical contacting of the electrode strips by gluing, it may be advantageous to set the viscosity of the paste higher, so that the conductive wires of a textile electrode tape 9 or a flat electrode 10 flat only partially sink in the conductive paste. Other cables, strands or electrically conductive threads or fibers can be glued so. By adjusting the viscosity of the electrically conductive paste, the degree of sinking of the terminal electrodes from the contact to the complete sinking into the paste can be controlled.

The electrode bands of the Fig. 3 are glued with the inventive electrically conductive paste only so that they are only partially enclosed by this and otherwise rest only on the conductive paste.

The electrode bands in the Fig. 4 are glued with the electrically conductive paste according to the invention only so that they rest only on the conductive paste and are only partially sunken in it, whereby they are at least partially surrounded by the paste.

LIST OF REFERENCE NUMBERS (Part of the description)

1. 1) electrically conductive sheet
2. 2) conductive plastic material as a printed electrically conductive pattern
3. 3) electrode
4. 4) decorative layer
5. 5) intermediate layer
6. 6) Textile layer / carrier layer
7. 7) metal filament
8. 8) Electrically conductive, curable polymeric paste
9. 9) Textile electrode band
10. 10) Ribbon-shaped flat electrode

Claims (4)

1. Electrically conductive sheet material, comprising an electrically conductive plastics material and electrodes in electrical contact with the plastics material, and comprising a current feed line, designed as surface material and/or decorative material, wherein the conductivity of the sheet material is provided at least partly by a layer of electrically conductive plastics material (2), which is bonded on the reverse side to the sheet material, the layer of electrically conductive plastics material (2) having semiconductor particles or metal particles, or fillers bearing semiconductors or metal, and the current feed line is designed as an electrode (3) which is sheetlike or of flat tape form, where the conductive contacting between the electrode (3) and the layer of conductive plastics material (2) is effected by an electrically conductive, curable polymeric paste (8), the electrode (3) having conductive filaments (7), the filaments (7) being at a distance from and disposed relative to one another, and the viscosity of the paste (8) being designed, in such a way that the paste (8) surrounds or penetrates the electrode (3), with embedding and/or inclusion of the filaments (7), and in curing joins the electrode (3) to the layer of conductive plastics material (2), characterized in that the layer of electrically conductive plastics material (2) covers the sheet material on the reverse side partially in gridlike or netlike disposition, and in that the electrically conductive curable polymeric paste (8) has three-dimensionally branched, conductive particles of dendritic design.
2. Electrically conductive sheet material according to Claim 1, wherein the layer of electrically conductive plastics material (2) exhibits conductive filaments, preferably conductive textiles with metal threads or metal-coated threads or carbon fibres.
3. Electrically conductive sheet material according to either of Claims 1 and 2, wherein the electrically conductive paste (8) is uncrosslinked or is admixed with a crosslinker only to a small extent of less than 2% by weight.
4. Electrically conductive sheet material according to any of Claims 1 to 3, wherein the sheetlike electrode (3) is provided with a thermoplastic polymer adhesive which can be reactivated by heat.

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