Electrically conductive yarn

Abstract

A yarn that is electrically conductive, that can be elongated considerably, at least briefly, without loss of conductivity, and that exhibits improved elongation properties.

Description

[0001] This application is a continuation-in-part of International Application No. PCT / DE2003 / 003059, filed Sep. 15, 2003, which claims priority to German Patent Application DE 102 42 785.2 filed Sep. 14, 2002 and German Patent Application DE 103 05 872.9 filed Feb. 13, 2003.FIELD OF THE INVENTIONS [0002] The present invention relates to elastic, electrically conductive yarns, their use and methods for their manufacture. BACKGROUND OF THE INVENTIONS [0003] Several methods are known for manufacturing electrically conductive yarns. For example, metal wires, wire mesh or metallized yarns have long been incorporated directly in fabrics to dissipate electrostatic charge. These fabrics are often difficult to produce on a loom and, due to the exposed wires, bear little optical resemblance to textiles and / or feel metallic to the touch. [0004] Furthermore, methods for manufacturing so-called staple yarns are known. Essentially, they involve spinning short textile fibers together with short a...

AI Technical Summary

Benefits of technology

[0019] According to a preferred embodiment of the present invention, the restoring force of the thread 4 increases disproportionately above a certain tensile load. The reason for this disproportionate rise in the restoring force lies in the binding thread 4. That is to say, above a certain tensile load, said binding thread can no longer give way to this load by spreading its helical form to a smaller number of turns per unit of length of the core thread 2, but rather allows a further extension only through an elongation in the longitudinal direction. The transition from an expansion of the helical structure to an effective extension of the binding thread itself in its lengthwise direction leads to a strong rise in the restoring force, preventing a further elongation of the yarn. This disproportionate increase in the restoring force occurs at a tensile load at which the electrically conductive thread has not yet broken. The yarn 1 is thus still conductive.

[0020] The scope of the extensibility of the binding thread 4 depends primarily on the material properties and the number of turns of the binding thread 4 around the core thread 2. Greater extensibility is generally achieved through a greater number of turns. In addition, a higher elongation at break of the material leads to increased extensibility.

[0027] Following elongation, the yarns according to the present invention should, due to the rubber elastic properties of the core thread, recontract to at least almost the original length. According to a preferred embodiment of the present invention, following an elastic elongation by at least 15% in the lengthwise direction, the electrically conductive yarn exhibits a maximum permanent elongation of 5% without loss of its electrical conductivity. Particularly preferably, following an elastic elongation by at least 30% in the lengthwise direction, the electrically conductive yarn exhibits a maximum permanent elongation of 5% without loss of its electrical conductivity.

[0031] Although, in principle, numerous metals and alloys, which may additionally be coated, anodized or etched, are suitable as conductive threads, copper wires, silver-coated copper wires and stainless steel wires are particularly preferred due to technical and economic factors. The use of coated or lacquered wire types improves the corrosion resistance and washability of the yarns according to the present invention. Not only are such yarns easily washable, but what is more, they even withstand dry-cleaning.

Problems solved by technology

These fabrics are often difficult to produce on a loom and, due to the exposed wires, bear little optical resemblance to textiles and / or feel metallic to the touch.

Such yarns are comparatively rigid and thus unusable for textile applications.

However, such yarns are not particularly extensible.

These yarns, too, do not exhibit good extensibility.

None of the above-described yarns can be appreciably elastically extended without loss of electrical conductivity, since the conductive threads either break or deform plastically.

None of these materials possesses rubber elastic properties.

The last-described yarns also cannot withstand elongations by more than 10% without a break or at least without loss of conductivity.

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