EP1413660A1 - Knitwear - Google Patents

Abstract

A pre-set proportion of the picks (2a,2b) forming the weft consists of conductive yarns and the knitted structure consists of nonconductive material. It can comprise stay yarns (3), which are formed at least in part out of a conductive material. Independent claims are made for applications of the material in curtains, mosquito nets or protective work clothing.

Description

The invention relates to a knitted fabric according to the preamble of claim 1.

In addition to woven goods and knitted fabrics, knitted fabrics represent a widespread form of manufacturing textiles. The knitted fabrics are usually produced using warp knitting machines or Raschel machines with weft insertion.

Such knitted fabrics consist of a vertical knitted structure with a horizontal weft insertion. The vertical knitted structure consists of a mesh structure and, if necessary, standing threads incorporated into it.

Knitted fabrics produced in this way are used in numerous applications. An essential area of application is the production of curtains. Due to the structural properties of the knitted fabrics, such curtains can be made transparent and still be largely non-slip.

The invention has for its object to provide knitted fabrics of the type mentioned, which are expanded in terms of their functionality.

The features of claim 1 are provided to achieve this object. Advantageous embodiments and expedient developments of the invention are described in the subclaims.

The invention relates to a knitted fabric with a vertical knitted structure and a horizontal weft insertion, the knitted structure and / or the weft insertion having conductive threads.

The conductive threads in the knitted fabric provide an efficient shielding effect against electromagnetic fields. Protection against electrostatic charges is also achieved.

This enables the knitted fabrics according to the invention to be used in numerous technical applications in which rooms are generally to be protected against the penetration of electromagnetic fields.

Through a sufficiently dense arrangement of the conductive threads, shielding surfaces can be formed with the knitted fabric according to the invention, which shield electromagnetic waves even at higher frequencies. Examples of this are waves emitted by cell phones or the like in the microwave range. The cut-off frequency of the frequencies that can be shielded is essentially predetermined by the grid spacing of adjacent conductive threads in the knitted fabric. The knitted fabric is only permeable to electromagnetic waves whose wavelengths are smaller than the spacing between adjacent conductive threads. Grid structures with grids in the range of 1-10 mm are preferably used.

Furthermore, the knitted fabric according to the invention forms a contactable structure. This means that the knitted fabric can be grounded, so that shielding against low-frequency electromagnetic fields is also possible.

The structure of the knitted fabric according to the invention is advantageously designed such that at least part of the weft insertion and / or part of the standing threads forming the knitted structure is formed by conductive threads, while the knitted structure of the knitted fabric consists of non-conductive material.

The main advantage of the knitted fabric formed in this way is that an efficient electromagnetic shielding effect is obtained with a small proportion of conductive threads.

In the event that only the weft insertion or only the standing threads are at least partially formed from conductive threads, the conductive threads form a linear structure of essentially parallel running conductive elements.

In a particularly advantageous embodiment, both the weft insertion and the standing threads of the knitted fabric according to the invention consist at least partially of conductive threads. In this case, a two-dimensionally networked structure of conductive elements within the knitted fabric is obtained, by means of which a particularly efficient shielding effect against electromagnetic fields is obtained.

In principle, the mesh structure could also be formed from conductive threads, which would result in a particularly close-meshed structure of the conductive threads. However, this would lead to a considerable increase in the manufacturing costs of the knitted fabric.

An essential advantage of the invention is the provision of transparent knitted fabrics with an electromagnetic shielding effect. By means of a suitable specification of the mesh structure, it is possible to form transparent knitted fabrics which, due to conductive threads in the weft insertion and / or in the standing thread structure, have an efficient electromagnetic shielding effect with little use of conductive threads. In addition, this structure gives the knitted fabric a high resistance to sliding.

Such transparent knitted fabrics are particularly suitable for the production of curtains or canopies, mosquito nets and the like.

Furthermore, the knitted fabrics can also be used for the production of work clothing, for example a transparent face protection.

The conductive threads for producing the knitted fabric according to the invention can generally be designed as metallic threads. Non-metallic conductive threads, such as carbon threads, can also be used.

Particularly advantageously, the conductive threads consist of a core yarn which has a core spun by sheath fibers, the core consisting of a metal-coated thread and the sheath fibers being formed by non-conductive fibers. The metal-coated threads can be designed as polyamide threads, polypropylene threads and the like.

A major advantage of this core yarn is that the electrically conductive component as part of the core lies inside the core yarn and is completely enclosed by the sheath fiber.

On the one hand, this protects the metal layer of the soul through the outer sheath fiber. In particular, abrasion of the metal layer on the polyamide threads of the core is avoided.

Furthermore, the surface properties of the core yarn can be specifically specified by the selection of the sheath fibers consisting of non-conductive fibers. It is advantageous that the sheath fibers completely enclose the metal layers of the core, so that the metal layers do not influence the surface properties of the core yarn.

It is essential that, despite the protective effect of the sheath fibers, they do not impair the conductivity of the core of the core yarn.

Figur 1:

Schematische Darstellung eines Ausführungsbeispiels des leitfähige Fäden aufweisenden erfindungsgemäßen Gewirks.

Figur 2:

Schematische Darstellung eines als Coregarn ausgebildeten leitfähigen Fadens für das Gewirk gemäß Figur 1.

The invention is explained below with reference to the drawings. Show it:

Figure 1:

Schematic representation of an embodiment of the knitted fabric according to the invention having conductive threads.

Figure 2:

Schematic representation of a conductive thread designed as a core yarn for the knitted fabric according to FIG. 1.

FIG. 1 shows an embodiment of the knitted fabric 1 according to the invention. The knitted fabric 1 is produced in the present case by means of a Raschel machine with weft insertion. In principle, knitted fabrics 1 of this type can also be produced by means of warp knitting machines with weft insertion.

The knitted fabric 1 according to FIG. 1 has a vertical knitted fabric structure with a horizontal weft insertion. The weft insertion consists of an arrangement of weft threads 2a, 2b. In the present case, the knitted structure consists of a stitch structure with standing threads 3. The standing threads 3 are typically worked into the knitted structure by means of a base bar (laying rail).

In the present case, the mesh structure consists of non-conductive materials. In general, the mesh structure can consist of natural fibers, synthetic fibers or mixtures thereof. The mesh structure can be formed from continuous fibers, staple fibers or mixtures thereof.

In the embodiment shown in Figure 1, the mesh structure of polyester threads 4 is formed. As can be seen from FIG. 1, the knitted structure is designed such that two polyester threads 4 each follow a vertical thread 3 running in the vertical direction. The standing threads 3 run in a wave form in the vertical direction along the knitted fabric 1.

The guidance of the standing threads 3 can be varied if necessary. A substantially straight or right-angled meandering guidance of the standing threads 3 is also possible.

The polyester threads 4 essentially also run in the vertical direction of the knitted fabric 1, but to form the stitch structure they also have segments which run almost horizontally, so that these are connected to the standing threads 3 form a networked structure. As can be seen from FIG. 1, the polyester threads 4 in the region of the uppermost weft thread 2a run essentially parallel to it and cross a standing thread 3. In the region of the second weft thread 2b, the polyester threads 4 run back in a substantially horizontal direction, again crossing the standing thread 3 and then continue in the vertical direction.

According to the invention, the standing threads 3 consist of conductive threads and thus form a conductive structure running in the vertical direction of the knitted fabric 1 for shielding from electromagnetic fields.

In principle, such a one-dimensional conductive structure is sufficient to achieve an electromagnetic shielding effect. In the present case, the shielding effect is increased in that some of the weft threads 2a also consist of conductive threads, so that a two-dimensionally cross-linked, conductive structure is obtained.

The knitted fabric 1 shown in FIG. 1 has a 1 full / 3 empty weft insertion. In FIG. 1 the needle positions 5 can be seen, at which the polyester threads 4 are gripped by means of needles (not shown) to form the stitch structure. As can be seen from FIG. 1, in every linear arrangement of the needle positions 5 running in the vertical direction, every fourth needle position 5 is covered with a weft thread 2a, 2b, followed by three free needle positions 5.

Every second weft thread 2a is designed as a conductive thread, while the remaining weft threads 2b consist of non-conductive material. In the present case, these weft threads 2b, like the mesh structure, consist of polyester threads 4.

In this way, a conductive network structure is obtained, which ensures efficient shielding of electromagnetic fields. The gap sizes this network structure are advantageously adapted to the wavelengths of the electromagnetic fields to be shielded. The upper limit frequency of the shielding fields is determined by the gap size.

The network structure can be predefined in a simple manner by the type of weft insertion, in principle a full weft insertion is also possible. The present embodiment with the 1 full / 3 empty weft insertion is particularly suitable for the production of transparent knitted fabrics 1, which are used, for example, for the production of curtains, bed canopies, mosquito nets or work clothes. With a predetermined type of weft insertion, the network structure can be predetermined by the proportion of conductive weft threads 2a and non-conductive weft threads 2b. Furthermore, the conductive network structure can be predetermined by the arrangement of the standing threads 3.

The conductive threads can generally be formed from differently structured metallic or metal-containing threads. Silver or copper, tin, nickel or gold are suitable as metals for forming the conductive threads.

Furthermore, the conductive threads can at least partially consist of non-metallic conductive substances, such as carbon.

In a particularly advantageous embodiment, the conductive threads are formed by core yarns 6. The structure of such a core yarn 6 is shown in FIG. 2.

The core yarn 6 consists of a core and the sheath fibers 7 surrounding it. The core is spun by the sheath fibers 7, known spinning processes of all kinds being able to be used for this purpose.

The core of the core yarn 6 consists of a polyamide thread 8, which are covered with a metal layer 9. The polyamide threads 8 of the soul can from monofilament or multiple fibers. Alternatively, the core can also consist of a polypropylene thread.

The metal layer 9 is preferably applied homogeneously on the entire surface of the polyamide thread 8. To apply the metal layer 9 to the polyamide layer, electrochemical and wet-chemical methods are used particularly advantageously in the field of electroplating. In an expedient embodiment, 8 so-called primers are first applied to the polyamide threads. This layer essentially forms an adhesion layer, on which metal clusters are finally deposited to form the metal layer 9. Alternatively, the deposition can also be carried out electrochemically by separating metal ions from an electrolyte liquid.

The thickness of the metal layers 9 on the polyamide threads 8 is preferably chosen so that the core of the core yarn 6 has a proportion of metal which is in the range of 10-15 percent by weight.

In principle, noble metals and base metals such as gold, copper, tin or nickel can be used as metals for the coating of the polyamide threads 8.

The metal layer 9 of the core of the core yarn 6 is particularly preferably made of silver, with ultra-pure silver being particularly advantageously used for the coating.

The thus formed metal-coated and thus electrically conductive core of the core yarn 6 is coated with the non-metallic sheath fibers 7. These sheath fibers 7 can be chosen freely, and in particular the sheath fibers 7 can be selected independently of the material properties of the core of the core yarn 6.

The sheath fibers 7 can generally consist of natural fibers, synthetic fibers or mixtures thereof. Examples of natural fibers are wool, cotton, animal hair, cashmere or mixtures of such natural fibers.

In particular, fibers made of polyester or acrylic can be used as synthetic fibers.

In general, the sheath fibers 7 can also consist of hollow fibers, these consisting in particular of acrylic.

A major advantage of this core yarn 6 is that, in addition to high conductivity values, it also has high elasticity. The high elasticity is obtained in particular through the use of the polyamide threads 8 for the core of the core yarn 6. This elasticity is retained when coating with the respective metal. It is particularly advantageous if the metal in question has a high ductility, which is particularly high for silver.

Correspondingly, the core yarns 6 have high elongation at break and a high recess, whereby elongations of the core yarn 6 are possible up to 20%.

In the event that the core of core yarn 6 has a metal layer 9 consisting of silver or copper, core yarn 6 also has antiseptic properties.

• Rolf Schumacher, 72336 Balingen, DE
• Mark Ziegele, 79801 Hohentengen, DE
• Oliver Sting, 72406 Bisingen, DE

While the formation of the core of the core yarn 6 specifies the conductivity of the core yarn 6 and in particular also determines other properties such as the antiseptic effect and elastic properties, the surface properties of the core yarn 6 are predetermined by the jacket fibers 7.

• Rolf Schumacher, 72336 Balingen, DE
• Mark Ziegele, 79801 Hohentengen, DE
• Oliver Sting, 72406 Bisingen, DE

LIST OF REFERENCE NUMBERS

(1)

knitted

(2a, 2b)

weft

(3)

filler thread

(4)

polyester thread

(5)

needle position

(6)

core yarn

(7)

clad fiber

(8th)

polyamide thread

(9)

metal layer

Claims (17)

Knitted fabric with a vertical knitted structure and a horizontal weft insertion, characterized in that the knitted structure and / or the weft insertion has conductive threads. Knitted fabric according to claim 1, characterized in that a predetermined proportion of the weft threads (2a) forming the weft insertion is formed by conductive threads. Knitted fabric according to one of claims 1 or 2, characterized in that the knitted structure has a mesh structure which is formed from non-conductive material. Knitted fabric according to one of claims 1-3, characterized in that the knitted structure has standing threads (3) which are at least partially formed by conductive threads. Knitted fabric according to one of claims 1-4, characterized in that the conductive threads consist at least partially of metal. Knitted fabric according to claim 5, characterized in that silver, copper, tin, nickel or gold can be used as metals. Knitted fabric according to one of claims 1-4, characterized in that the conductive threads at least partially consist of non-metallic materials, in particular carbon. Knitted fabric according to one of Claims 1-6, characterized in that the conductive threads are formed as core yarns (6) with a core spun by sheath fibers (7), the core consisting of metal-coated threads, and the sheath fibers (7) not metallic fibers are formed. Knitted fabric according to claim 8, characterized in that the core consists of metal-coated polyamide threads (8). Knitted fabric according to one of claims 8 or 9, characterized in that the core has a metal content of 10-15 percent by weight. Knitted fabric according to claims 8-10, characterized in that the sheath fibers (7) consist of natural fibers, synthetic fibers or mixtures thereof. Knitted fabric according to one of claims 1-11, characterized in that its non-conductive components consist of natural fibers, synthetic fibers or mixtures thereof. Knitted fabric according to claim 12, characterized in that its non-conductive components are formed by continuous yarns, staple fibers or mixtures thereof. Textile surface consisting of a knitted fabric (1) according to one of claims 1-13. Textile surface according to claim 14, characterized in that it is transparent. Use of textile surfaces according to one of claims 14 or 15 for the production of curtains. Use of textile surfaces according to one of claims 14 or 15 for the manufacture of bed canopies, mosquito nets or protective work clothing.

Images