DE10242785A1 - Electrically conductive yarn has a stretch core filament, with an electrically conductive and a bonding filament wound around it to restrict the core stretch - Google Patents

Abstract

The electrically conductive yarn has a stretch core filament, with an electrically conductive filament wound around it together with a non-conductive bonding filament of natural or synthetic fibers. The bonding filament limits the stretch of the elastic core. The core, of a natural rubber or synthetic elastic material, has a stretch to break of at least 50% and preferably at least 100% and especially at least 200%. The conductive filament is a metal wire, or a synthetic fiber filament or multi-filament yarn with a metal cladding.

Description

field of use

The present invention relates to elastic, electrically conductive Yarns, processes for their manufacture, fabrics made therefrom and applications. Preferred areas of application of the yarns according to the invention and tissue lie in the data transmission and the power supply of electrical or electronic components. Can also yarns according to the invention or products made of electromagnetic shielding Fields or to derive static charges.

background

There are some methods of making electrical conductive Yarns known. To discharge electrostatic charge for a long time metal wires or wire mesh or metallized yarn worked directly into the fabric. These fabrics are often problematic to manufacture on the loom and they feature due to the exposed wires over a only limited textile optics and l or a metallic handle.

Methods for producing so-called staple yarns are also known. Essentially short textile fibers are spun into a yarn together with short and very fine metal fibers. Depending on the metal content, these yarns have more or less textile or metallic properties. Stacking yarns with good electrical conductivity have a metallic look and feel. Methods are also known in which centrally guided metal wires are wrapped in single or double textiles. Since it is essentially the wire that determines the tensile strength in these yarns, relatively thick wires with diameters greater than 0.1 mm are usually used. Such yarns are relatively stiff and therefore unusable for numerous textile applications. In EP 0250260 B1 describes how thin wires can be used in the core of a wound yarn by wrapping parallel wire and textile thread. In this arrangement, the central textile thread ensures tear resistance, while the thin wire running in parallel ensures the electrical conductivity of the yarn. Such yarns are not particularly stretchy.

In CH 690686 A5 describes the production of a composite yarn from a textile fuse and monofilament metal thread. During the yarn spinning process on a ring spinning machine, the fuse is fed a coated metal wire centrally. In the thermal treatment following the spinning process, the melting coating glues the central wire to the spun textile covering. Such yarns are not particularly stretchy.

None of the yarns described above can to a significant extent without loss of electrical conductivity be stretched elastically because the conductive threads either tear or deform plastically.

In the scriptures US 4776160 . US 5881547 and US 5927060 yarns are described in which electrically conductive threads are wound around centrally arranged yarns. In principle, this arrangement enables a certain stretching of the entire yarn unit without a priori causing an ineversible stretching or breaking of the conductive wrap. US 5881547 teaches the manufacture of a highly tear-resistant, electrically conductive yarn for use in fencing clothing. Due to the large diameter of the stainless steel wires used, these yarns are very stiff in the range between 0.6 mm and 1.2 mm, hardly stretchable and in no way elastic. As well in US 4776160 , as well as in US 5927060 the necessity of using flexible and stretchable core threads for the production of conductive yarns with good textile properties is shown. In US 4776160 it is assumed that the preferred elongation at break of the core thread is 10% to 15%. The minimum elongation at break is only 3%. None of the in US 4776160 The core yarns mentioned have rubber-elastic properties. This in US 5927060 described yarn can withstand an elongation of about 5% without changing the electrical conductivity. The textile core thread used there has no rubber-elastic properties. In addition, the weak winding with only 200 to 600 turns per meter allows only a small amount of stretch under the given conditions until the wrapping wire breaks.

The yarns described last don't have any rubber-elastic properties. Even if they have low stretches survive in the range of 3% to 5% without loss of electrical conductivity can, this leaves clear residual strains. Stretches by more than 10% can the yarns described last also not without demolition or at least Survive without loss of conductivity.

An object of the invention is Providing yarns that are electrically conductive and that are without loss this property can be significantly stretched at least for a short time can. After stretching, the yarns according to the invention should become more elastic due to the elasticity Properties at least approximately back to the original Pull length together.

Another object of the invention is the readiness the provision of yarns that are essentially free of internal torsional stresses and can therefore be processed without any problems.

Another object of the invention is the provision of washable or chemical cleaning resistant yarns and fabrics.

Another object of the invention is the provision of self-protecting against excessive stretching Yarns and fabrics.

Another object of the invention is the provision of electrically conductive materials similar to one Ribbon cable, or a spatially resolvable two-dimensional Matrix different electrical signals without any significant mutual Ability to transport influence side by side. Another object of the invention is the provision of electromagnetic shielding yarns and tissues.

Another object of the invention is the provision of antistatic yarns and fabrics.

Another object of the invention is the provision of processes for the production of the yarns according to the invention.

With the yarns according to the invention are composite yarns with an elastic core and one electrically conductive sheathing.

The elastic core thread or threads are for the elastic properties of the entire yarn unit. The market offers a variety of rubber elastic threads out of that for suitable material can be selected for the respective application can. This includes among other things natural and synthetic rubbers, the different polyester and polyether elastane types, modified polyesters, post-crosslinked Thermoplastics etc. These materials can be used for the application suitable forms are used. Some variants are exemplary called: monofilament, multifilament, segmented types and textured types. If necessary, you can also several threads parallel or twisted in the core. They can be of the same type or different threads can be used side by side.

The elastic core of the composite yarn is equipped with at least one electrically conductive wrap. The thread used must be wound around the core in such a way that an elongation of the entire yarn unit by 15% no plastic deformation or causing a break causes mechanical stress on the winding thread. The elastic Core can be used several times with conductive Wound around threads his. This conductive Can wrap also be applied in different winding directions and if necessary be separated from one another by intermediate layers. Corresponding the application of the yarn according to the invention is the thread select from the class of electrically conductive materials. Next Other materials are particularly suitable for metallic wires, wire threads or -braids, conductive coated synthetic fibers, staple yarns with metal content and conductive filled Synthetic fibers. The winding threads can be simple or multiple, mixed or mixed.

Monofilament used for winding metal wires are for numerous embodiments of the invention, especially in one Thickness range between 0.01 mm and 0.1 mm suitable. Although in principle numerous metals and alloys that are additionally coated or pickled could be, for the production of yarns according to the invention with wire, because of technical and economic factors Copper wires, silver-coated copper wires and stainless steel wires particularly preferred.

In addition to monofilament metal wires multifilament stainless steel yarns are excellent for manufacturing the yarns according to the invention. Typically, the thickness of a single stainless steel filament moves in the range between 0.002 mm and 0.02 mm. The number of included Individual filaments are between 10 and 200.

• – Elektrische Isolierung (nach außen, nach innen oder zwischen mehreren leitfähigen Schichten)
• – Mechanischer Abriebschutz
• – Verbesserung der Verarbeitbarkeit des Garns auf schnell laufenden Maschinen
• – Farbe, Glanz, Optik
• – Griff, Haptik
• – Überdehnschutz
• – Reißfestigkeit
• – Ausgleich der inneren Torsionsspannung des Garn nach Umwindung in einer Richtung

The use of silver-coated synthetic yarns for electrically conductive wrapping around the elastic core is suitable for numerous applications. The market offers both monofilament and multifilament yarns. With multifilament yarns as a wrap, higher surface coverage of the core can be achieved with the same yarn diameter compared to monofilament fibers. Depending on the application, this can be an advantage or a disadvantage. In addition to the electrically conductive wrap, the yarn can include an electrically non-conductive wrap. Such a winding can perform various functions. To illustrate the possible tasks of such a yarn component, an incomplete list should be given here:

• - Electrical insulation (outside, inside or between several conductive layers)
• - Mechanical abrasion protection
• - Improving the processability of the yarn on high-speed machines
• - color, gloss, look
• - Handle, feel
• - Over-stretch protection
• - tear resistance
• - Compensation of the internal torsional tension of the yarn after winding in one direction

For numerous applications, a yarn structure with an internal one is suitable elastic core, inner winding with conductive thread and in the opposite direction more detailed textile outer wrapping. The outer wrapping is preferred in this way in such a way that in the event of a strong stretch before the internal conductive Winding completely is excited. So can the outer winding slow down a stretch before the conductive wrap is damaged.

Further preferred embodiments of the Yarns according to the invention include the use of multifilament yarns for non-conductive winding. When winding around a core, multifilament yarns preferably lie flat on the core, so that they have a significantly higher surface coverage than the monofilament with the same outer diameter.

Depending on the application for the described non-conductive winding all possible threads are suitable. vicarious for the potential Examples include: nylon, polyester, viscose, Polyamide, linen, wool, silk, cotton, polypropylene, kevlar in the different embodiments as well as mixed yarns of all kinds.

The production of the yarns according to the invention can be done in different ways. In this document it is preferred methods of classic yarn winding described in more detail. The central elastic thread is warped on a drafting system. The warped elastic core thread is made by a rotating hollow spindle guided. The bobbin with the winding thread sits on the hollow spindle. The Wrapping thread is from the evenly pulled elastic Core thread taken, so that the winding thread in the form of a spiral is wound around the core thread. The warped core thread relaxes after winding again, the individual windings lie essentially denser than during of winding. Rubber-elastic yarns can be compared to inelastic ones Yarns with high warpage are produced, which are otherwise identical Production conditions through the described relaxation of the yarn leads to significantly tighter windings after winding. elastic Yarns can can be wound more closely with the above-mentioned method than non-elastic ones. Simply wound yarns are usually not free of internal torsional stress, i.e. that they twist into themselves when unwinding from the spool. To produce a balanced yarn, it is simply wrapped Wound around the yarn again. The second winding takes place in the opposite direction to the first turn.

Examples

To illustrate the invention in the following examples for the production and processing of yarns according to the invention listed. At this point it should be explicit it should be noted that the invention is not to the specified Examples limited should be.

Example 1:

An elastic thread made of Lycra 163C (Du Pont de Nemours GmbH, Du Pont Strasse 1, D-61352, Bad Homburg) with 1880 dtex is stretched on a yarn winding machine. The pre-stretched Lycra thread is passed through a hollow spindle. This Hollow spindle carries a conical thread spindle, of which a 0.041 mm thick, hard silver-plated one Copper wire is pulled through the lycra thread. Just with Wire wrapped lycra is passed through a second hollow spindle. This Hollow spindle carries a commercial one Multifilament polyamide yarn made of PA66 with 78 dtex and 34 individual filaments. The PA66 yarn runs in opposite directions wrapped around the core as a wire. The machine parameters are like this selected, that a balanced yarn is created that is as free as possible from internal torsional stresses is. The outer PA66 Yarn is wound around the core 3200 times per meter of yarn; the inner Wire is wound around the core 3600 times per meter of yarn. The inside Wire is close Completely from the outside PA66 yarn covered so that the yarn has a textile look and feel features. The yarn has excellent electric conductivity. With a stretch of approx. 250%, the restoring force of the yarn is reduced full Elongation of the PA66 yarn disproportionately stronger. At about 300% elongation, the yarn loses due to broken wire its electrical conductivity.

Example 2:

The elastic, electrically conductive composite yarn from example 1 is used as a weft on a standard weaving machine. The warp beam consists of 0.3 mm thick, simply twisted cotton threads, which are combined in groups of 8 threads. When weaving, a firm fabric is created which has excellent electrical conductivity in the weft direction and does not conduct the electrical current in the direction of the warp thread. These electrical properties are retained even after stretching by more than 120% in the weft direction. If the poles of a DC voltage source are connected at a distance of 6 mm in the warp thread direction, this voltage can be used at a distance of one meter in the weft thread direction to operate an electrical consumer, such as a light-emitting diode. The fabric can be stretched in the weft direction without affecting the power supply to the light emitting diode.

Example 3:

The elastic, electrically conductive composite yarn from example 1 is used as a weft on a standard weaving machine. The warp beam consists of an electrically conductive, but not rubber-elastic composite yarn. To produce the warp thread, a commercially available polyester yarn with 100 dtex and 36 individual filaments with an inner winding made of 0.041 mm thick, silver-plated copper wire and an outer winding made of commercially available polyamide yarn (PA66) is included 78 dtex and 34 single filaments equipped. Weaving creates a strong fabric that has excellent electrical conductivity in the weft direction and an independent electrical conductivity in the direction of the warp thread. These electrical properties are retained even after stretching by more than 120% in the weft direction. This fabric, which can be produced inexpensively, can be used with a corresponding electronic control as a matrix for spatially resolving signal acquisition or for operating a spatially resolving output unit, such as a screen.

Example 4:

An elastic thread made of Lycra 163C (Du Pont de Nemours GmbH, Du Pont Straße 1, D-61352, Bad Homburg) with 1880 dtex is stretched on a yarn winding machine. The pre-stretched Lycra thread is passed through a hollow spindle. This Hollow spindle carries a conical thread spindle, one of which is coated with silver Polyamide thread with 30 denier and 18 individual filaments (X-static, Life SRL, I-25015 Desenzano, Italy) by the Lycrafaden becomes. The Lycra simply wrapped with the silver-coated fiber is guided through a second hollow spindle. This hollow spindle carries a commercially available Multifilament polyamide yarn made of PA66 with 33 dtex and 10 individual filaments. The PA66 yarn runs in opposite directions wrapped around the core as a silver-coated fiber. The machine parameters are selected so that a balanced yarn is created that is as free as possible from internal torsional stresses is. The outer PA66 Yarn is wound around the core 3200 times per meter of yarn; the silver-coated Thread is wound around the core 3600 times per meter of yarn. The inside silver coated thread is not completely from the outside PA66 yarn covered. The yarn has excellent electric conductivity. With a stretch of approx. 250%, the restoring force of the yarn is reduced full extension of the PA66 yarn disproportionately stronger. at tear about 320% elongation those enveloping the Lycra Yarns.

Example 5:

The elastic, electrically conductive composite yarn from example 4 is used as a weft on a standard weaving machine. The warp beam consists of an electrically conductive, but not rubber-elastic composite yarn. To produce the warp thread, a commercially available polyester yarn with 100 dtex and 36 individual filaments with an inner winding is made from a silver-coated polyamide thread with 30 denier and 18 individual filaments (X-static, Life SRL, 1-25015 Desenzano, Italy) and an outer winding commercial polyamide yarn (PA66) with 33 dtex and 10 single filaments. Weaving creates a strong fabric that has excellent electrical conductivity. Due to the incomplete insulation of the silver-coated wraps in both the warp and weft threads, all electrically conductive yarns in the fabric are in electrical contact with one another. This direction-independent electrical conductivity is retained even after stretching by more than 100% in the weft direction. Such a fabric has excellent shielding properties against electromagnetic radiation in the 1 to 2000 MHz range.

Claims (14)

Electrically conductive yarn, consisting of at least one elastic core thread and at least one electrically conductive thread wound around the core, characterized in that the yarn can be stretched by at least 15% in length without loss of electrical conductivity and that the yarn after an elongation of 15% has a maximum residual elongation of 5%. Electrically conductive Yarn according to claim 1, characterized in that for the manufacture of the Yarns used elastic core thread with an elongation at break of more has more than 60% and a residual elongation after an elongation of 30% less than 5%. Electrically conductive Yarn according to the claims 1 or 2, characterized in that the one used for winding electrically conductive Thread a monofilament metal wire with a diameter between 0.01 mm and 0.1 mm. Electrically conductive Yarn according to the claims 1 or 2, characterized in that the one used for winding electrically conductive Thread is a metallic coated synthetic fiber, being next to monofilament silver-coated fibers silver-coated multifilament yarns are preferably used. Electrically conductive Yarn according to the claims 1 or 2, characterized in that the one used for winding electrically conductive Thread is a metallic multifilament yarn, preferably stainless steel fibers be used. Electrically conductive Yarn according to one of the preceding claims, characterized in that at least one electrically non-conductive thread is used for winding becomes. Electrically conductive yarn according to claim 6, characterized in that the electrically conductively wrapped elastic core is wound on the outside with an electrically non-conductive yarn, the outer wrapping preferably being designed in such a way that it limits the extensibility of the entire yarn unit before the inner electrically conductive wrapping breaks. Electrically conductive Yarn according to one of the preceding claims, characterized in that the electrically conductive Thread at least 1000 times per meter of yarn around the elastic core is wrapped. Process for making any of the foregoing claims mentioned yarn comprehensively - the mechanical warping of the elastic core thread on a drafting system - the leadership of the warped core thread through an electrically conductive thread load-bearing and around the longitudinal axis rotating hollow spindle. A method according to claim 9, characterized in that the warped and already simple with an electrically conductive thread wrapped core thread by an electrically non-conductive thread load-bearing and around the longitudinal axis rotating second hollow spindle is guided, this second hollow spindle opposite rotates to the first hollow spindle. Fabric comprising one of those mentioned in the above claims Yarn. Use of one of those mentioned in the above claims Yarn for transmission of electrical signals, with which both analog and digital Signals are meant. Use of one of those mentioned in the above claims Yarns or products made therefrom for supplying electrical or electronic units with electrical current. Use of one of those mentioned in the above claims Yarns or products made therefrom for shielding electromagnetic Fields or to derive static charges.