Cord and Pneumatic Vehicle Tire

Abstract

A cord (1) for use in an elastomer product, preferably in a pneumatic tire, comprising a reinforcement system (2) which is made of an electrically nonconductive material and which is sheathed by an electrically conductive layer (5).

Located on the electrically conductive layer (5), covering same, there is a further, electrically insulating layer (6).

Claims

1.-11. (canceled)

12. A cord for use in an elastomer product, the cord comprising a reinforcement core which is made of an electrically nonconductive material, wherein the reinforcement core is covered by an electrically conductive layer, wherein disposed upon the electrically conductive layer is an electrically insulating layer, and wherein the electrically conductive layer comprises electrically conductive particles selected from the group consisting of carbon black particles, graphite powder or carbon nanotubes.

13. The cord as claimed in claim 12 comprising a plurality of electrically conductive layers and a plurality of electrically insulating layers, in alternating sequence, wherein the outermost layer is an electrically insulating layer.

14. The cord as claimed in claim 12, wherein the electrically insulating layer is substantially free from electrically conductive particles.

15. The cord as claimed in claim 12, wherein the electrically insulating layer comprises electrically nonconductive particles.

16. The cord as claimed in claim 12, wherein at least one of the electrically insulating layer and electrically conductive layer is based on an elastomer-containing solution or suspension.

17. The cord as claimed in claim 16, wherein the electrically conductive layer is based on an elastomer-containing solution or suspension, and wherein the elastomer-containing solution or suspension comprises from 10% by weight to 70% by weight of the electrically conductive particles.

18. The cord as claimed in claim 16, wherein the electrically insulating layer is based on an elastomer-containing solution or suspension, and wherein the elastomer-containing solution or suspension comprises from 10% by weight to 70% by weight of electrically nonconductive fillers.

19. The cord as claimed in claim 12, as comprised in an elastomer product, and wherein the elastomer product comprises at least one of such cords

20. A cord for use in an elastomer product, the cord comprising a reinforcement core which is made of an electrically nonconductive material, wherein the reinforcement core is covered by an electrically conductive layer, wherein disposed upon the electrically conductive layer is an electrically insulating layer, and wherein the electrically insulating layer comprises electrically nonconductive particles.

21. The cord as claimed in claim 20 comprising a plurality of electrically conductive layers and a plurality of electrically insulating layers, in alternating sequence, wherein the outermost layer is an electrically insulating layer.

22. The cord as claimed in claim 20, wherein the electrically conductive layer comprises electrically conductive particles selected from the group consisting of carbon black particles, graphite powder or carbon nanotubes.

23. The cord as claimed in claim 20, wherein the electrically insulating layer is substantially free from electrically conductive particles.

24. The cord as claimed in claim 20, wherein at least one of the electrically insulating layer and electrically conductive layer is based on an elastomer-containing solution or suspension.

25. The cord as claimed in claim 24, wherein the electrically conductive layer is based on an elastomer-containing solution or suspension, and wherein the elastomer-containing solution or suspension comprises from 10% by weight to 70% by weight of the electrically conductive particles.

26. The cord as claimed in claim 24, wherein the electrically insulating layer is based on an elastomer-containing solution or suspension, and wherein the elastomer-containing solution or suspension comprises from 10% by weight to 70% by weight of electrically nonconductive fillers.

27. The cord as claimed in claim 20, as comprised in an elastomer product, and wherein the elastomer product comprises at least one of such cords

28. A cord for use in an pneumatic tire, the cord comprising a reinforcement core which is made of an electrically nonconductive material, wherein the reinforcement core is covered by an electrically conductive layer, and wherein disposed upon the electrically conductive layer is an electrically insulating layer.

29. The cord as claimed in claim 28, wherein the cord is included in a radial carcass of the pneumatic tire.

30. The cord as claimed in claim 28, wherein the electrically conductive layer comprises electrically conductive particles selected from the group consisting of carbon black particles, graphite powder or carbon nanotubes.

31. The cord as claimed in claim 28, wherein the electrically insulating layer comprises electrically nonconductive particles.

Description

[0017] The invention will now be explained in more detail with reference to a diagram of an inventive example.

[0018] FIG. 1 shows a cross section through an embodiment of an electrically conductive cord.

[0019] FIG. 1 shows a cross section through an electrically conductive cord 1 consisting of an externally coated reinforcement core 2. The reinforcement core 2 can be a monofilament, a yarn or a cord consisting of a plurality of yarns. FIG. 1 shows a yarn made of a large number of filaments 3. The reinforcement core 2 consists of non-metallic textile material, for example rayon, polyester, polyamide or aramid, and is therefore electrically nonconductive. The reinforcement core 2 can also consist of various non-metallic materials.

[0020] The cord 1 has a multilayer coating 4, which has two layers in the embodiment shown in FIG. 1. The layer 5 located directly on the reinforcement core 2 is electrically conductive, and can consist of carbon black, graphite powder or carbon nanotubes or of an elastomer-containing material which by way of example is based on a latex or on a suspension which comprises another elastomer and which comprises electrically conductive particles which ensure that the layer 5 is electrically conductive, an example being carbon black particles, graphite powder or carbon nanotubes. The layer 5 can by way of example be produced by using a conventional adhesion promoter which comprises carbon black particles and which is sufficiently liquid to permit use of dipcoating to coat the reinforcement core 2. It is possible by way of example to use an RFL dip (resorcinol-formaldehyde latex dip) incorporating carbon black particles, in particular N339 particles or N121 particles. The proportion of electrically conductive particles in the suspension is from 10% by weight to 70% by weight, and particularly preferably from 30% by weight to 50% by weight. The proportion of the dried layer 5 in the cord 1 is from 7% by weight to 20% by weight, preferably about 10% by weight. Sheathing the external side of the electrically conductive layer 5 which surrounds the reinforcement core 2 there is another layer 6, which however is electrically insulating. The electrically insulating layer 6 is by way of example likewise applied by dipcoating to the layer 5. The electrically insulating layer 6 is in particular based on an elastomer-containing solution or suspension, for example a latex solution which preferably no electrically conductive particles, or a suspension in which the concentration of electrically conductive particles, for example carbon black particles, is so small as not to cause any electrical conductivity. Production of the electrically insulating layer 6 can likewise be based on a conventional adhesion promoter liquid, for example an RFL dip. A preferred embodiment uses an elastomer-containing suspension which is by way of example likewise based on latex and which, in particular in order to improve the mechanical properties of the layer 6, comprises electrically nonconductive fillers, in particular fine-particle silica. The proportion of electrically nonconductive fillers in the suspension is from 10% by weight to 70% by weight, preferably from 30% by weight to 50% by weight. The proportion of the dried layer 6 in the cord 1 is from 7% by weight to 20% by weight, preferably about 10% by weight.

[0021] The electrically insulating exterior layer 6 permits arrangement of a plurality of cords 1, which are electrically conductive by virtue of the layer 5, alongside one another while these have no electrical effect on one another and on contact do not generate short circuits, in particular in a conductive rubber matrix. Cords 1 coated in the invention can therefore also be arranged so as to cross one another. It is particularly advantageous to use the cords 1 as electrically conductive elements for providing contact to electrical elements, sensors and actuators in rubber products, in particular in pneumatic tires.

[0022] In another embodiment of the invention, another electrically conductive layer, similar to the layer 5, can be applied on the exterior layer 6, and a second electrically insulating layer, similar to the layer 6, can be applied thereto. It is thus possible to apply a plurality of electrically conductive and electrically insulating layers in alternation, so that the cord comprises a plurality of separate electrically conductive passageways.

LIST OF REFERENCE NUMERALS

[0023] 1 . . . Cord

[0024] 2 . . . Reinforcement core

[0025] 3 . . . Filament

[0026] 4 . . . Coating

[0027] 5 . . . Layer

[0028] 6 . . . Layer