HEATING ELEMENT, AND HEATABLE PANE COMPRISING A HEATING ELEMENT

• US 20100059494A1
• Filed: 01/10/2008
• Published: 03/11/2010
• Est. Priority Date: 01/26/2007
• Status: Active Grant

• Current Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Original Assignee: Tesa SE (maxingvest GmbH & Co. KGaA)
• Inventors: Prenzel, Alexander, Lühmann, Bernd, Keite-Telgenbüscher, Klaus
• Granted Patent: US 9,332,593 B2
• Time in Patent Office: Days
• US Class Current: 219/201
• CPC Class Codes: H05B 2203/013 Heaters using resistive films or coatings
• CPC Class Codes: H05B 2214/04 Heating means manufactured by using nanotechnology
• CPC Class Codes: H05B 3/12 characterised by the composition or nature of the conductive material
• CPC Class Codes: H05B 3/86 the heating conductors being embedded in the transparent or reflecting material H05B3/845 takes precedence

Abstract

A heating element including a current conductor through which electric power is conducted and electricity converted into heat by a voltage drop across an ohmic resistor. The heating element is a planar or a strip-shaped structure and is provided with at least one support layer and an adhesive layer, while the current conductor is designed as an additional, current-conducting layer which is arranged between the support layer and the adhesive layer. The support layer, the current-conducting layer, and the adhesive layer are transparent.

Claims

1. A heating element having a current conductor for conducting electrical current, wherein, as a result of a drop in voltage at an ohmic resistor, the current is converted into heat,

wherein the heating element is a planar structure in form of a tape having at least one backing layer and an adhesive layer,

the current conductor is formed as a current-conducting layer,

the current-conducting layer is disposed between the backing layer and the adhesive layer, and

the backing layer, the current-conducting layer, and the adhesive layer are transparent.

2. The heating element of claim 1, wherein the current-conducting layer is designed such that at least 90% of the current flowing overall through the heating element flows through the current-conducting layer.

3. The heating element of claim 1, wherein the current-conducting layer comprises carbon nanotubes.

4. The heating element of claim 1, wherein the heating element has regions with different heating power.

5. The heating element of claim 3 wherein the carbon nanotubes are embedded in a transparent matrix.

6. The heating element of claim 5, wherein the transparent matrix has a polymeric binder,

7. The heating element of claim 6, wherein the monomers for preparing the matrix material are selected such that the resulting polymers are used as pressure-sensitive adhesives at room temperature or higher temperatures.

8. The heating element of claim 5, wherein the matrix material is a pressure-sensitive acrylate adhesive.

9. The heating element of claim 8, wherein two surface regions are provided for introduction of current into the current-conducting layer and

wherein in the surface regions there is either no adhesive layer disposed on the current-conducting layer and/or there is a different kind of electrically conductive layer disposed, said layer having an electrical conductivity which is at least 10 times higher than that of the current-conducting layer.

10. The heating element of claim 8, wherein two further transparent layers are disposed above and below the current-conducting layer, and are likewise electrically conductive, said layers having an electrical conductivity which is at least 10 times higher than that of the current-conducting layer.

11. The heating element of claim 3, wherein the carbon nanotubes have an average length of at least 10

12. The heating element of claim 3, wherein the carbon nanotubes have an average outer diameter of less than 40 nm.

13. The heating element of claim 3, wherein the carbon nanotubes have an average ratio of length to outer diameter of at least 250.

14. The heating element of claim 3, wherein the surface of the carbon nanotubes is chemically modified.

15. The heating element of claim 3, wherein the carbon nanotubes are single-walled carbon nanotubes.

16. The heating element of claim 3, wherein the carbon nanotubes are multi-walled carbon nanotubes.

17. The heating element of claim 3, wherein more than one of the carbon nanotubes within the current-conducting layer are oriented in a preferential direction.

18. The heating element of claim 3, wherein the current-conducting layer, in addition to the carbon nanotubes, has further conductive components, preferably intrinsically conductive polymers.

19. The heating element of claim 1, wherein the adhesive layer is designed as a self-adhesive layer.

20. The heating element of claim 19, wherein the self-adhesive is an acrylate adhesive.

21. The heating element of claim 19, wherein the self-adhesive is a styrene block copolymer adhesive.

22. The heating element of claim 19, wherein the self-adhesive has a transparency of greater than 70%, preferably greater than 80%, more preferably greater than 90%.

23. The heating element of claim 1, wherein the layer which substantially conducts the current has a transparency of not more than 80%.

24. A heatable pane with a heating element, wherein

the heating element is designed in accordance with claim 1.

25. The heatable pane of claim 24, wherein the pane is composed of mineral glass or plastic glass.

26. The heating element of claim 1, wherein the current-conducting layer is designed such that at least 95% of the current flowing overall through the heating element flows through the current-conducting layer.

27. The heating element of claim 1, wherein the current-conducting layer is designed such that at least 98% of the current flowing overall through the heating element flows through the current-conducting layer.

28. The heating element of claim 4, wherein the heating element has regions with different heating power, in that the current-conducing layer has a regionally different concentration of carbon nanotubes and/or a regionally different thickness.

29. The heating element of claim 6, wherein the polymeric binder is converted into the current-conducting layer from a solution or dispersion in one or more organic solvents or in water.

30. The heating element of claim 18, wherein the current-conducting layer comprises conductive components.

31. The heating element of claim 30, wherein the conductive components are intrinsically conductive polymers.

32. The heating element of claim 22, wherein the transparency is greater than 80%, more preferably greater than 90%.

33. The heating element of claim 22, wherein the transparency is greater than 90%.

34. The heatable pane of claim 25, wherein mineral glass or plastic glass is Plexiglas.