CZ28603U1 - Sewing thread for integration of electronic elements into fabrics - Google Patents

Description

Technical field

The technical solution relates to the sewing thread, in particular for the integration of electronic elements into smart fabrics and smart garments.

Background Art

Prior art electrically conductive sewing threads are not suitable for use in smart fabrics and smart garments, i.e., fabrics and garments, which are intended to interfere with electronic components or to create customized functional electronic elements (e.g., sensors, antennas, etc.). Especially because of el. resistance and fineness of the sewing thread. According to the information obtained, there are conductive sewing threads for technical purposes such as antistatic sewing, special filter clothing and the like. The fineness of these threads is about 90 tex, with the need for the sewing thread fineness to 55 tex for application to smart garments. Some companies offer sewing threads for sewing antistatic clothing. In this case, their el. the resistance ranges from 10 ⁵ to 10 ⁷ Q / m. For the needs of smart textiles and smart clothing, it is required that el. the resistance of the sewing threads allowing electrical connection of the electronic function blocks does not exceed 10 ² Ω / m.

The main requirement for conductive thread in terms of electrical properties is to achieve the highest electrical conductivity. For the practical use of conductive threads designed for conducting electric current and for transmitting signals, the value of electrical resistance should be a maximum of Ω per 1 meter of thread to minimize voltage drops. For special sensor applications such as temperature measurement or for heating element construction, the electrical resistance value can range from hundreds to tens of kΩ per 1 m of thread. Other required electrical parameters include a maximum current carrying capacity which should be at least hundreds of mA for a single conductive yarn.

In addition, the sewing threads are subjected to various types of stresses, not acting alone but in different combinations, during and during the bonding process:

During the bonding process, mechanical stress (bending, abrasion, thrust) occurs, thermal stress (in the thread friction in the needle tab, friction between the thread and the machine parts), impact stress (when changing the sewing speed and direction, these stresses are combined and their effects are multiplied), During mechanical and thermal stress, especially during wear and maintenance.

Therefore, the following qualities must be ensured for the threads in the required quality: strength, impact strength, loop strength, fineness and ductility corresponding to the sewn material, stability of twists, loopiness, abrasion resistance, bending stiffness, deformation properties, shrinkage, surface smoothness sewing thread, uniformity, heat resistance, sewing ability of threads (number of thread breaks per unit of time, time to break of sewing thread). It is also necessary to take into account the behavior of the threads during processing, wearing and maintenance (processing and performance). In terms of utility properties, the durability of the seam thread, the durability (color, shape) in use and maintenance, the aesthetic appearance, the tensile strength, the elasticity, the abrasion resistance, the comparable shrinkage with the sewn material are monitored.

Above mentioned properties, during the bonding process, the resistance of the thread to abrasion is of particular importance. The thread passes through the working mechanisms of the sewing machine (the brake, the wires), the needle of the needle and it abrasions. As a result, the surface of the thread is broken and may break. The greatest strain then occurs in the handle of the machine sewing needle, where the thread is reciprocating (one place on the sewing thread passes through the needle of the needle up to 40x). In the case of synthetic fiber yarns, a portion of the fibers are deposited in the loop of the needle due to melting. This restricts the passage of the yarn and breaks.

The conductive fibers known so far can be divided into the following categories:

Carbon Additive Fibers: These fibers have a conductivity of 10 ^-5 to 10 S.cm ^-1 , depending on the carbon content. The main applications are products for antistatic purposes, their textile processing characteristics are good. Of course, pure carbon fibers exhibit better conductivity, e.g., greater

-1 EN 28603 Ul than 10 ² S cm ^-1, but are much more difficult to process. In any case, the above electrical properties are not sufficient in terms of the required electrical properties for their use in smart fabrics and smart garments. The specific property of any carbon-containing fiber is its black color, which may be disadvantageous in many applications.

Fibers coated with metal salts: Copper sulfide is an example. These compounds have a relatively low conductivity of 10 ^-6 to 10 ^-1 S.cm ^-1 , so that the resulting fibers are suitable where low el. resistance. Their main advantage is that they can be easily processed with conventional textile technology.

Metal Fibers: According to the findings of the professional press, the group of metal filaments includes both fibers made of pure metal and metallized fibers. They are supplied in the form of continuous filaments or staple fibers for textile processing. They produce yarns, fabrics, knits. The staple can be mixed with, for example, cotton or polyester.

In general, metal fibers (steel, brass, silver) have the highest conductivity. On the other hand, due to their metallic nature, they exhibit several processing problems. They are fragile, with a tendency to abrade machinery and difficult to mix with other fibers due to their high specific density. Last but not least, they have a metallic touch.

Metal fiber based fabrics are used to make protective clothing that has excellent antistatic properties. Their use in the protection against electromagnetic radiation has recently become more important. There is a growing awareness of the potential dangers associated with human exposure to electromagnetic radiation. Its effect on organic tissues, especially in the microwave range (GHz), has been known before, but only nowadays the exposure limits begin to regulate, for example DIN VDE 6848.

The application of conductive textiles in this area covers the range from conductive networks for video terminals to conductive seals designed to shield microwave electromagnetic radiation sources and thereby protect the operator from unwanted long-term exposure to such radiation. Such environments are found in the military (radar operators), hospitals (both patients and computed tomography operators), universities and research centers (nuclear magnetic resonance (NMR) operators) and communications technologies (power transmitter maintenance). Smart clothing is another application for metal fibers. These garments are already being used by athletes, rescuers, the military and workers in various industries. One of the prerequisites for progress in this area is to master the new technologies for processing metal fibers and conductive polymers.

Metallised fibers have recently appeared on the market. The metal coating of these fibers is achieved in three different ways:

Physical Procedure: Vacuum deposition (steamed) aluminum is generally used. This solution is relatively inexpensive and the resulting fibers achieve a high conductivity of 10 to 10 ⁴ S.cm ^-1 depending on the metal deposited. Due to the low adhesion between the metal and the substrate fibers, they exhibit very poor workability, low wear and maintenance resistance.

Electroplating: This procedure is applicable only to carbon and graphite fibers because it requires a conductive substrate. The fibers thus coated have a high conductivity > 10 ⁴ S.cm ^-1 . They are mainly used for the preparation of composite fibers for strengthening in aerospace applications. Due to its high price and difficult workability, the textile industry uses them only marginally.

Chemical Plating: This process is very flexible because it is suitable for almost any substrate fiber. Its main advantage is that it allows the fibers to obtain a high conductivity of 10 ² to 10 ⁴ S.cm ^-1 without significantly altering other substrate properties such as density, flexibility, feel. Due to these characteristics, the metallized fibers can be easily processed by conventional textile technology.

The essence of the technical solution

The above-mentioned drawbacks of the prior art are eliminated by electrically conductive sewing thread, in particular for integrating electronic elements into smart fabrics and smart garments, which according to this

The invention comprises at least one metal fiber having a diameter of 0.01 to 0.05 mm and at least one polymeric fiber having a fineness of 4 to 18 tex.

Preferably, said metal fibers have a diameter of 0.02 to 0.03 mm and are silver-plated copper, brass or bronze.

Also preferably, the polymeric fiber is polyester rayon, or polyamide or viscose rayon, and has a fineness of 5.5 to 13.5 tex.

The sewing thread has a fineness of 30 to 60 tex, with a polymer fiber content of 30 to 60% and a metal fiber content of 20 to 70%.

In addition, such a sewing thread may comprise a yarn made of polyester staple and fibers having a polyamide core and a silver sheath.

The basic requirements for sewing threads that are intended for the aforementioned applications are low electrical resistance, good processing and utility properties, including health (do not cause allergic reactions or skin irritation by direct contact).

Based on the required electrical parameters of the conductive motif, it is possible to define the electrical resistance of the sewing thread in a defined manner during the manufacturing process. In case the thread is used to produce temperature sensor elements, an el. resistance ranging from 1 to 10 kQ per 1 m of its length. At the same time, conductive threads made for temperature sensor elements exhibit a temperature coefficient of response (TKR) in the range of 900 to 1400 ppm / ° C. It reaches el. Resistance range from 5 to 80 Ω / m thread. The maximum current carrying capacity of the threads ranges from 500 mA to 800 mA according to its type.

The object of the utility model application is therefore a conductive hybrid sewing thread based on a composition of ultra fine metal fibers, continuous chemical fibers and optionally conductive yarns.

The fineness of the conductive yarns is preferably 15-20 tex.

Production technology may include the following sub-operations:

1. First twist on an annular bouncing machine:

In this operation, the curled material is given a "S" twist. The sweeping and twisting is performed at 600 to 900/1 m - as required and specific conditions. In this operation, multiple input components are simultaneously:

- one or more high strength polyester filament yarns of, for example, 55 dtex, 74 dtex or 138 dtex,

-One or more special ultra-fine metal fibers

and optionally conductive spun yarn.

In some cases, it may be necessary to move the material to a suitable coil shape prior to first twisting, or to spread it over a plurality of coils.

These operations affect other follow-up work. The problem is the process of unwinding the ultra-fine metal fiber from the countershaft where there is a risk that a tear may occur due to its low strength. In addition, some metal fibers exhibit loopiness which causes it to break or unwind loops into the thread.

2. Second twist on an annular bouncing machine:

In this operation, the sewing thread is twisted in the "Z" direction. In order to obtain the final thread, after the first operation it is necessary to classify the next skam: 2x, 3x or 4x yarn from the first twist. The number of twists granted is 400 to 900/1 m - as required and specific conditions. If necessary, steam fixation, e.g., 80 ° C, is included; 30 minutes; 0,1 MPa.

-3GB 28603 U1

3. Rewind to the desired format, such as rolls, cones or king coils.

If necessary, the preparation is carried out, so that the sewing threads are applied to the sewing threads to improve the sliding properties during sewing and to reduce the friction between the conductive part of the sewing machine and the thread. Most often, a silicone-paraffin emulsion is used for this purpose. If a greater percentage of the composition of the yarn is needed on the yarn, the yarn can be wound over several times.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail by way of example and drawings, wherein in Fig. 1 a fabric with a textrode of a sewing thread according to the present invention and Fig. 2 is a fabric with temperature sensor elements of a sewing thread according to the present invention.

Description of exemplary embodiments

The manufacturing technology of a special electrically conductive hybrid sewing thread enables the production of sewing threads of varying number of elementary ultra fine metal fibers. For specific needs, it is possible to produce a hybrid sewing thread composed of ultra-fine metal fibers, polyester filament and spun yarn spun, for example, from conductive chemical fiber SilveR.STAT® and polyester staple fibers. SilveR.STAT® is a fiber with a polyamide core and a silver sheath manufactured by R.STAT SAS.

Example 1

Sewing thread 50% polyester filament + 50% ultra fine metal filament.

First twist - 600 or 820 S twists: two high-strength polyester fibers PESh (polyester filament) of 74 dtex + three metal filaments of 0.02 mm diameter silver plated copper, which have electrical resistance: min. 51.69 [Ω / m], nominal 54.41 [Ω / m] and max 57.13 [Ω / m].

Second twist (490 or 550 of twists): two yarns obtained from the first twist are gathered.

Resulting sewing thread parameters: fineness: 32 tex, dry dry strength: 33.22 cN / tex, dry ductility: 13.76%, electrical resistance: 9.5 ± 0.5 [Ω / m]

Example 2

Sewing thread with 32% polyester filament thread, 36% ultra-fine endless metal filament (6 elemental ultra-fine metal filaments), 32% yarn with 60% SilveR.STAT® + 40% polyester staple fiber 18 tex.

First twist (600 S twists): one high-strength polyester PESh 13.5 tex + one yarn of SilveR.STAT® and polyester staple + three silver-plated copper fibers 0.02 mm in diameter, with electrical resistance: min. 51.69 [Ω / m], nominal 54.41 [Ω / m] and max 57.13 [Ω / m]

Second twist (600 S twists): one high-strength polyester fiber PESh 135 dtex + three silver-plated copper fibers 0.02 mm in diameter, with electrical resistance: min. 51.69 [Ω / m], nominal 54.41 [Ω / m] and max 57.13 [Ω / m]

Third Twist (490 of Twists): One yarn obtained from the first twist and one yarn from the second twist are cut.

The resulting sewing thread parameters: fineness: 44 tex; relative dry strength: 25.7 cN / tex, dry ductility: 14.0%, electrical resistance: 10.4 ± 0.5 [Ω / m]

Example 3

Sewing thread of 31% polyester filament, 69% ultra fine filament, 6 threads of ultra fine metal fibers.

-4CZ 28603 Ul

First twist (820 S twists): one high-strength polyester fiber PESh of 55 dtex + two metal fibers of 0.03 mm in diameter made of brass that have electrical resistance: min. 53.76 [Ω / m], nominal 56.59 [Ω / m] and max 59.42 [Ω / m].

Second Twist (456 From Twists): Three yarns obtained from the first twist are gathered.

Resulting sewing thread parameters: fineness: 54 tex, dry dry strength: 22.76 cN / tex, dry ductility: 10.77%, electrical resistance: 9.8 ± 0.5 [Ω / m].

Example 4

Sewing thread with 42% polyester filament thread, 23% ultra-fine endless metal filament (2 elemental ultra-fine filament metal threads), 35% yarn with composition: SilveR.STAT® 60% / 40% polyester staple, softness 18 tex.

First twist (820 S twists): two PESh 55 dtex polyester fibers + one 0.03 mm brass metal fiber with electrical resistance: min. 53.76 [Ω / m], nominal 56.59 [Ω / m] and max 59.42 [Ω / m],

Second twist (556 of twists): two yarns obtained by first twisting + one yarn of SilveR.STAT® and polyester twine.

Resulting sewing thread parameters: fineness 54 tex, relative dry strength 35.26 cN / tex, dry ductility 12.85%, electrical resistance: 29.2 ± 0.5 [Ω / m].

Alternatively, instead of two 55 dtex polyester fibers, one high-density 110 dtex PESh polyester fiber can always be used in the first fold.

In particular, metal fibers of brass, bronze or copper with a silver shell can be used in particular.

The electrically conductive hybrid sewing thread according to the present invention meets the requirements in terms of electrical properties and sewing capabilities required for their use in the field of smart fabrics and smart garments. This conductive sewing thread can be used in both the top and bottom sewing processes. It is suitable for sewing on standard sewing machines as well as on special embroidery machines such as Tajima. On embroidery machines, this thread can be used to produce fully functional conductive motifs for sensor applications as well as custom sensor elements (such as temperature or humidity sensors), textile electrodes (textrody), and conductive bonding structures. For example, in Fig. 1, a fabric with a sewn-on electrode (textrode) from the sewing thread of Example 1 is shown, and Fig. 2 is a fabric with temperature sensor elements of a sewing thread.

It will be appreciated that in the drawings, only examples of possible shapes of sewn textrods or sensor elements are shown, and that various possible integrated patterns can be made with the sewing threads of the present invention.

The advantage of sewing threads according to the present invention is that they have a low electrical resistance (generally up to 10 k k / m, in some cases up to 100Ω / m) and good utility properties, including health, do not cause allergic reactions or skin irritation. For some types of yarn, the change in electrical resistance depends on the ambient temperature expressed by the temperature coefficient of resistance of 900 to 1400 ppm / ° C. Although a number of exemplary embodiments have been described, it will be appreciated that one skilled in the art will readily find other possible alternatives to these embodiments. Therefore, the scope of the invention is not limited to these exemplary embodiments, but rather is defined by the definition of the appended Claims.

Claims (14)

PROTECTION REQUIREMENTS 1. Sewing thread, in particular for the integration of electronic components into smart textiles and smart clothing or for the integration of temperature sensors into textiles, characterized in that it comprises at least One metal fiber having a diameter of 0.01 to 0.05 mm and at least one polymer fiber having a fineness of 4 to 18 tex, which are jumped together. Sewing thread according to claim 1, characterized in that said at least one metal thread has a diameter of 0.02 to 0.03 mm. Sewing thread according to claim 1 or 2, characterized in that the at least one metal thread is made of stainless steel or silver-plated copper, or brass or bronze. Sewing thread according to any one of the preceding claims, characterized in that the at least one polymer fiber is polyester filament yarn or polyamide filament yarn or viscose rayon. Sewing thread according to any one of the preceding claims, characterized in that said at least one polymer fiber has a fineness of 5.5 to 13.5 tex. Sewing thread according to any one of the preceding claims, characterized in that the fineness is 30 to 60 tex. Sewing thread according to any one of the preceding claims, characterized in that the polymer fiber content is 30 to 60% and the metal fiber content is 20 to 70%. Sewing thread according to any one of the preceding claims, characterized in that it comprises a pair of yarns twisted together, each comprising one polyester fiber and three silver-plated copper fibers. The sewing thread of any one of claims 1 to 7, further comprising a yarn formed of a polyester staple and a fiber having a polyamide core and a silver sheath. Sewing thread according to claim 9, characterized in that the content of said yarn in the sewing thread is 25 to 50%, in particular 30 to 35%. Sewing thread according to any one of claims 1 to 7, characterized in that it comprises a pair of twisted yarns, the first comprising three metal fibers and one silver-coated polyamide fiber and the second comprising three metal fibers and one or two polyester fibers. Sewing thread according to any one of claims 1 to 7, characterized in that it comprises a triple yarn which is mutually interwoven, each comprising two metal fibers and one or two polyester fibers. Sewing thread according to any one of the preceding claims, characterized in that the polymer fiber is a monofilament or a smooth or bulky multifilament. A sewing thread according to any one of claims 1 to 7, characterized in that it consists of a pair of yarns twisted together, each consisting of one to two polyester fibers and one to three metallic fibers of silver-plated copper or brass.